CHC410
Internship Project Report
Submitted by
Lavanya Kumar Jain
2007CH10069, Student
Chemical Engineering Department, IIT Delhi, New Delhi, India
Phone: +91 9953181003; Email: [email protected]
Faculty Supervisor
Anurag S. Rathore
Associate Professor
Chemical Engineering Department, IIT Delhi, New Delhi, India
Phone: +91-9650770650; Email: [email protected]
Indian Institute of Technology Delhi Trident Complex, Raikot Road, Hauz Khas, New Delhi Barnala, Punjab,
India-110016 India-148101 http://www.iitd.ac.in Tel: +91-161-5039999, Fax: +91-161-5038800
http://www.tridentindia.com
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INTERNSHIP SUMMARY
Name of the Company: Abhishek Industries Ltd (Trident Group)
Internship period: 17th
May – 16th
July 2010
No. of days: 52
Location: Dhaula complex, Barnala, Punjab
Department: Production
Unit: Paper (PPR)
Project Supervisor: Mr. Sumit Jindal, FLE, Recovery 2, PPR
Abhishek Industries Limited
Phone: +91 9878997774; Email: [email protected]
Project Title: Reduction of chemical losses in Recovery
ABSTRACT
The project at Abhishek Industries is concerned to analysing ORE and identifying sources of soda loss
in the whole process and suggesting measures to reduce soda loss. The streams carrying alkali are
studied and all the possible exit points for alkali are identified. The major sources of loss are
individually studied and various measures are suggested to increase their performance and reduce
soda loss. Experiments are conducted at several occasions to analyze the affects of suggested
measure.
The method of ORE calculation is also corrected and automation is suggested at several points for
better control of process. ORE is calculated based on individual losses from soda loss sources.
Summary of the Report:
1. IDENTIFICATION OF ALKALI EXIT POINTS: Recovery 2 plant and Pulp mill are rigorously
analyzed and all the possible exit points of alkali from the system are identified. Process flow
diagram for each unit is provided.
2. FMEA ON ALKALI EXIT POINTS: Results are derived from FMEA and a final list of prominent
alkali loss points is made based on Perito hypothesis.
3. WBL SAMPLING TO STUDY VARIATION IN COMPOSITION: WBL samples are analysed at
frequent intervals to study variation in actual WBL composition to value used for ORE
calculation. Error in SRE and ORE values due to above variation is calculated.
4. COMPOSITE SAMPLING AND AUTOMATION: Collection tank design for composite sampling is
proposed. Advantages of Automation and suppliers of online analyzers are provided.
5. MUD FILTER ORE LOSS: ORE loss from mud filter is calculated from lime consumption and %
composition data of mud cake. Loss from Grifts and stones is also calculated.
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6. MUD FILTER PROCESS PARAMETER ANALYSIS: Process parameters that affect performance of
mud filter are identified and analyzed. Experiments are done to test vat solid composition,
homogeneity in vat mixture. Impact of displacement washing on alkali content in mud cake is
discussed.
7. CAUSTICIZING CONTROL MODELS: 3 causticizing control models, including Advanced control
are discussed to maintain consistent causticizing efficiency and avoid excess lime addition.
8. PULP MILL SODA CARRYOVER ORE LOSS: From production data and Soda as kg/MT TTA as
Na2O, total soda loss and loss in ORE is calculated.
9. PULP MILL PRODUCTION VERSUS SODA CARRYOVER LOSSES: Soda carryover with production
for SFL and WFL are plotted and the trend is analysed.
10. WASHER EFFICIENCY FOR SFL AND WFL: Project in SFL and WFL to reduce soda loss are
discussed.
11. TOTAL WASHABLE ALKALI AS SODA CARRYOVER IN WFL: Elemental analysis of filtrate of
thoroughly washed pulp is done to calculate total washable alkali of total alkali as soda
carryover in WFL.
12. PULP MILL REJECT ORE LOSSES: Total soda loss and total washable soda loss calculations are
done for reject streams in SFL and WFL. ORE loss through reject stream is calculated using
these data.
13. REJECT STREAM WASHING SOLUTIONS: Reject streams in SFL and WFL are thoroughly studied
with sufficient flow diagrams. Solutions are suggested to reduce soda loss through reject.
14. ESP PROCESS PARAMETER ANALYSIS: Various process parameters are identified and analysed
that affect the performance of ESP.
15. COLLECTION EFFICIENCY CALCULATION: Ash collection rate from ESP is calculated from AMT
density sampling at specific intervals of time. Inlet gas flowrates are noted during the sampling
period. With other parameters constant collection efficiency is calculated for the ESP.
16. DUST COMPOSTION: ESP dust composition and Chlorine Enrichment Factor (CEF) and
Potassium Enrichment Factor (PEF) are calculated.
17. POTASSIUM AND CHLORIDE PURGING: The problem of high content of chlorides and
potassium in the system is discussed. Methods for their removal and systems based on Ash
Leaching are provided.
18. ORE LOSS DATA: Tentative % Loss in ORE from all the loss points is presented. ORE based on
individual losses is calculated.
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INDEX
Contents Page Number
Internship Summary 2
Abstract 2
Abhishek Industries 6
1. Introduction 11
1.1. Paper making process 11
1.2. Paper plant at Abhishek Industries 11
1.3. Recovery units 12
1.4. ORE 16
2. Objective 17
3. Project Plan 17
4. Alkali Exit Points 18
4.1. Recovery 2 17
4.2. SFL 24
4.3. WFL 26
4.4. Significant permanent loss points 26
5. WBL Sampling 30
5.1. ORE fluctuations 30
5.2. WBL sampling 32
5.3. Composite sampling 36
5.4. Automation 38
6. Mud Filter 39
6.1. Lime Mud ClariDisc system 39
6.2. Mud Filter ORE loss 40
6.3. Process parameter testing 41
6.4. Causticizing control models 48
7. Pulp mill soda carryover 49
7.1. Pulp mill soda carryover ORE loss 49
7.2. Pulp mill production versus soda carryover losses 50
7.3. Washer efficiency for SFL and WFL 54
8. Pulp mill Reject 56
8.1. Pulp mill Reject ORE losses 56
8.2. Reject stream washing 59
9. ESP 63
9.1. BHEL ESP system 64
9.2. Process parameters 65
9.3. Collection Efficiency 70
9.4. Dust Composition 74
9.5. Potassium and Chloride Purging 75
9.6. ESP ORE Loss 77
10. ORE Loss data 78
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11. Future Work 79
12. References 80
List of Experiments 81
List of Tables 81
List of Figures 82
Appendix A (Data Tables) 84
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ABHISHEK INDUSTRIES
Trident Group commenced its operations in 1985 with Single Super Phosphate (capacity 66000
tonnes per annum) & Sulphuric Acid (capacity 33000 tonnes per annum). Since then, the business of
the group witnessed a wide range of diversification and expansions and today, Trident Group is a Rs.
25 billion global conglomerate with an employee headcount of more than 10,000, and providing
indirect employment to 20,000 people. Therefore, Trident is a pioneer at implementing sound
Corporate Governance as the basic management principle.
Abhishek Industries Limited (AIL) is the flagship company of the Trident Group and deals in Yarns,
Towels, Papers, and Chemicals & Energy. The company is among the top 5 global terry towel giants
of the world. It is one of the world's largest agro-based paper manufacturers and one of the largest
yarn producers in India. Abhishek Industries has 3 plants located at Dhaula (Punjab), Sangheda
(Punjab) and Budhni (Madhya Pradesh).
At present the company is having following manufacturing facilities:
• Yarns 12592 spindles
• Yarn Processing 6825 tonnes/ day
• Open end Yarn 1920 rotors
• Terry Towels 268 looms
• Writing & Printing Papers 400 tonnes/ day
• Sulfuric Acid 100000 tonnes/ annum
In brief,
Leadership: Mr. Rajinder Gupta, CEO and MD
Ownership: Public limited company with Public shareholding 36.52 %, and Foreign shareholding
6.32 %.
Total Assets: Rs. 25 billion
CAGR: 30%
Employees: Over 10,00 (Indirect employment to 20000 people)
Exports: 47% of Net Sales across 65 countries
Financial Performance, (Rs. millions)
PERIOD ENDED MAR 2009 MAR 2010
NO. OF MONTHS 12 12
GROSS TURNOVER 15456 19768
NET SALES 13981 18034
EXPORTS 6862 8392
GROSS PROFIT (PBIDT) 2605 3560
NET PROFIT AFTER TAX (530) 565
NET WORTH 4463 5028
FIXED ASSETS (GROSS BLOCK) 21032 23388
CURRENT ASSETS (NET) 2365 5285
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MUSKAAN, SHAAN, SGA
Several employee engagement initiatives including Total Quality Assurance (TQA), Kaizen
(MUSKAAN), SHAAN, Small Group Activity (SGA) etc have been taken up for creating a quality driven
culture through the involvement of ground level employees. These initiatives focused on building
awareness and developing skills in Kaizen, 5 S, etc.
MUSKAAN
MUSKAAN is company’s own nomenclature for KAIZEN. This initiative has been undertaken so as to
ensure that members in the Organization undertake small improvements of permanent nature in
their own work area and department. The focus of the initiative is to help reduce strain and extra
effort, improve quality and reduce inconsistencies and any wasteful activity. The Organization is now
moving towards Phase II and the focus is towards facilitating innovation, creativity and process
improvements.
SHAAN
Like Muskaan, SHAAN is company’s own nomenclature for 5 S. The program has been initiated to
harness the benefits of increased efficiency due to reduced time in looking for tools and equipment,
improved quality, work standardization, reduced changeover time, and improved safety, reduced
space requirements & storage costs, reduced machine down time and simplified work environment,
etc. Regular trainings are being imparted to our members on the same.
SGA
Small Group Activities have been undertaken by members for improving the process capability in all
the production and support processes and to make the processes more efficient.
ABHISHEK YARN, TEXTILES, PAPER, SAP, COGEN, UTILITY
ABHISHEK YARNS
The Yarn Division of the company manufactures both Combed and Carded yarn in addition to
polyester cotton and PVA yarn. Besides catering to the captive consumption by Home Textiles
Division, the Yarn Division has developed a significant presence in the export market with its quality
products.
Currently, AIL has 125,952 spindles operating at almost 100% capacity producing value added yarns
such as yarn made from Egyptian cotton, PVA fiber and Bamboo fiber. Also, AIL has upgraded its
existing spinning facilities through automation and increasing the value adding processes.
Abhishek Yarns supplies the processed yarns to the following mills: Arvind Mills; Elegant Overseas;
Kapoor Industries; Abhitex Industry; Chemitax, Belgium; SPL Industries; Aashima Industries and Alok
Industries.
ABHISHEK TEXTILES
The Home Textiles Business of the company is the prime source of Export Earnings and International
Recognition to the company. AIL supplies its Toweling products to world’s biggest and most reputed
companies and retail chain stores like Wal*Mart, Luxury Linens, JC Penney, Target, BBB, Chris
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Madden, TJ Maxx, Franco and Sears. Among the top 20 retailers of the world, AIL has business
relationship with at least 11 of them. The company has a significant presence in the mid and high
segment of the Terry Towel market, with an impressive product profile. Currently, the division
operates with an installed capacity of 268 looms of towels and 6825 TPA of processed yarn. Ultra-
modern German, Swiss and Italian technology has been adopted in order to provide consumers the
products that they cherish.
ABHISHEK PAPER
The Paper Division of Trident was commissioned in 1992 and presently the production capacity is
400 TPD. The focus is on manufacturing Writing and Printing grades of paper for different segments.
The unit specializes in using Wheat Straw, an Agro residue as its prime raw material, thus facilitating
an eco-friendly environment and maintaining the ecology of the place.
Applications:
a. Calendar & Diary Printing
b. Business & Computer Stationery
c. Multicolor High End Printing & Publishing
d. Base paper for coated papers
e. Novels publication
f. High Speed Photocopying
g. Laser & Inkjet Printing
h. Multipurpose Office Use Paper
At Abhishek Industries there are two pulp units, Pulp 1 for producing pulp from wood i.e. wood fiber
line (WFL) and Pulp 2 for producing pulp using wheat straw i.e. straw fiber line(SFL). The SFL unit is
the biggest pulp producing unit in the world that utilizes wheat straw as a raw material.
SAP (SULFURIC ACID PLANT)
Sulfuric acid is produced from sulfur, oxygen and water via the conventional contact process (DCDA)
In the first step, sulfur is burned to produce sulfur dioxide.
S (s) + O2 (g) → SO2 (g)
This is then oxidized to sulfur trioxide using oxygen in the presence of a vanadium (V) oxide catalyst.
2 SO2 (g) + O2 (g) → 2 SO3 (g) (in presence of V2O5)
The sulfur trioxide is absorbed into 97-98% H2SO4 to form oleum (H2S2O7), also known as fuming
sulfuric acid. The oleum is then diluted with water to form concentrated sulfuric acid.
H2SO4 (l) + SO3 → H2S2O7 (l)
H2S2O7 (l) + H2O (l) → 2 H2SO4 (l)
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The production of SAP is 100000 tonnes/ annum
Figure 1. Sulfuric Acid Plant (SAP) at Abhishek Industries, Dhaula complex
COGEN
The units of Abhisehk Industries meet their own energy demands. There are 5 COGEN units with 2
large units of 20 MW each and 3 units of combined capacity of 9.34 MW. The total power generation
capacity is 49.34 MW. The requirement is 40 MW. Steam is the main product of these units and is
converted to different temperature and pressure conditions depending on requirements.
Figure 2. COGEN-1, a 20 MW unit at Abhishek Industries, Dhaula complex
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UTILITY
There is waste water treatment plant and effluent treatment plant in the Dhaula industrial campus.
It reduces BOD and COD of streams and protects environment. Also, a demineralised water plant
supplies demineralised water to all the units.
Figure 3. Demineralised water plant at Abhishek Industries at Dhaula complex
In brief,
BUSINESS UNIT CAPACITY PRODUCTION
(2010)
REVENUE
(Rs. millions)
Abhishek Home Textiles (AHT)
1998 374 looms 29,152 tonnes 8,482.5
Abhishek Yarn
1992
224,448 spindles and
1,920 rotors 48,115 tonnes 6,187.0
Abhishek Paper
2002 175,000 tpa 123,629 tonnes
4,951.8 Abhishek Chemicals
1985 1,00,000 tpa 84,038 tonnes
COGEN Power 50 MW 328,534 Mwh units
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1. INTRODUCTION
1.1. PAPER MAKING PROCESS
Paper making process involves pulping of the raw material. Pulping can be carried out through
chemical pulping or mechanical pulping. For chemical pulping there could be various processes, viz.
Kraft process, sulphite process and soda pulping. Sulfite pulping is carried out between pH 1.5 and 5,
depending on the counterion to sulfite (bisulfite) and the ratio of base to sulfurous acid. The pulp is
in contact with the pulping chemicals for 4 to 14 hours and at temperatures ranging from 130 to 160
°C.1 In the Soda-AQ process, anthraquinone (AQ) may be used as a pulping additive to decrease the
carbohydrate degradation. The soda process gives pulp with lower tear strength than other chemical
pulping processes.2
Kraft process is the most common applied process and entails treatment of raw fiber with a mixture
of sodium hydroxide and sodium sulfide, known as white liquor, that break the bonds that link lignin
to the cellulose. Cooking produces black liquor that contains lignin fragments, carbohydrates from
the breakdown of hemicellulose, sodium carbonate, sodium sulfate and other inorganic salts. A
Recovery plant process black liquor and produces White liquor to be reused in the digester for
cooking.
Figure 1.1. Paper making process
1.2. PAPER PLANT AT ABHISHEK INDUSTRIES
The paper plant at Abhishek Industries is based on Kraft Process. The capacity of paper plant is 400
MT/day. However, current production is 420 MT/day. The raw material used for making paper is a
mixture of wheat straw and wood chips in ratio of approximately 70:30. By using the wheat straw as
1 http://en.wikipedia.org/wiki/Sulfite_process
2 http://en.wikipedia.org/wiki/Soda_pulping
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raw material, Abhishek industries has saved thousands of trees for being used to make paper, but
using wheat straw has its own disadvantages in purity and paper quality. It also faces problem of
limited research on plant processes.
A paper plant basically consists of a Pulp Mill, Paper Machine and Finishing section and utility as
Recovery. At Abhishek Industries there are 2 pulp mills, SFL and WFL. Straw Fiber Line (SFL)
processes wheat straw and produces pulp, with present production around 230 tonnes of bleached
pulp per day. Wood Fiber Line (WFL) processes wood chips and produces pulp, with present
production around 100 tonnes of bleached pulp per day. There are 2 paper machines, Paper
Machine 1 and Paper Machine 2. There are 2 Recovery Units, Recovery 1 and Recovery 2.
Figure 1.2. Paper making flowchart3
1.3. RECOVERY UNITS
The first step of chemical recovery is the evaporation process, which increases the concentration of
solids from approximately 15 percent to more than 60 percent. The concentrated slurry contains
approximately 50 percent organic solids and 6 percent total sulfur in the form of sodium sulfate
3 Mckean W. and Jacobs R. S. (1997) Wheat Straw as a Paper Fiber Source
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(Na2SO4) and sodium thiosulfate (Na2S2O3) and is placed into a recovery boiler. The organic solids are
burned for energy while the inorganic process chemicals, also known as smelt, flow through the
floor of the recovery boiler to be recausticized.4
Quick Lime
To Energy
Lime Mud
Figure 1.3. Chemical Recovery Cycle
At Abhishek Industries, Recovery 1 has a capacity of around 130 tonnes of dry solids fired per day
and Recovery 2 has a capacity of 400 tonnes of dry solids fired per day.
1.3.1. MULTIPLE EFFECT EVAPORATORS
Figure 1.4. Multiple effect evaporators
4 M. Brongers, A. J. Mierzwa. Pulp and Paper
Raw Material
[Wheat Straw/ Wood Chips]
Pulping
Weak Black Liquor
(WBL)
[10-12 % Solids]
White Liquor
Evaporator
Heavy Black
Liquor (HBL)
Combustion
[Recovery Boiler] Green Liquor
Causticizer Lime
Kiln
Limestone Makeup
Steam
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The first step in recovering the chemicals from the black liquor is evaporation. This removes excess
water from the black liquor and maximizes the fuel value for the recovery furnace.
1.3.2. RECOVERY BOILER
Figure 1.5. Recovery Boiler Process flow
Figure 1.6. Recovery Boiler
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A recovery boiler consists of heat transfer surfaces made of steel tube; furnace-1, superheaters-2,
boiler generating bank-3 and economizers-4. The steam drum-5 design is of single-drum type. The
air and black liquor are introduced through primary and secondary air ports-6, liquor guns-7 and
tertiary air ports-8. The combustion residue, smelt exits through smelt spouts-9 to the dissolving
tank-10.
1.3.3. RECAUSTICIZING PLANT
Figure 1.7. Recausticizing Process flow
Recausticizing is the process used to transform the inorganic smelt recovered from the recovery
boiler into white liquor so that the chemicals may be recycled. The recycled inorganic chemicals are
discharged as molten smelt from the recovery boiler and then dissolved using water to form green
liquor. Any unwanted substances are precipitated out. Lime is then added to the clarified green
liquor to produce sodium hydroxide (NaOH) from the remaining sodium carbonate (Na2CO3). The
resulting solution (white liquor) contains sodium hydroxide, sodium sulfide (Na2S), and a solid phase
of calcium carbonate (lime mud). Before the white liquor is recycled back to the digester, the white
liquor is clarified further to remove the lime mud.5
The main necessities for Soda Recovery Plant are:
a. Maintaining required Chemical Oxygen Demand (COD) and Biochemical Oxygen Demand
(BOD) levels as per Environmental regulations.
COD of inlet liquor to recovery plant is in lakhs, while regulations are 300 for COD and 30 for
BOD.
b. Recovery of caustic soda (NaOH) that results in cost benefits.
c. Energy production as steam by burning organic material in black liquor, lignin.
5 M. Brongers, A. J. Mierzwa. Pulp and Paper
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1.4. OVERALL RECOVERY EFFICIENCY
As the purpose of a Soda Recovery unit is to recover caustic soda from Black liquor, it calculates the
total efficiency of caustic soda recovered through a generalized term as Overall Recovery Efficiency
(ORE) which incorporates caustic soda losses both at pulp mills and in recovery units.
ORE = SRE X PME
Soda Recover Efficiency,
SRE = (WL supply to Pulp mill) ± (Recovery stock difference)
WBL Received
Pulp Mill Efficiency,
PME = (WBL received by recovery) ± (WBL stock difference of Pulp mill)
(WL supply to Pulp mill) + (Purchased caustic) ± (WL stock difference of PM)
1.4.1. ORE CALCULATIONS
Basis: TTA as Na2O
A WL used in cooking in SFL and WFL
B OS of WBL+WL in SFL and WFL
C OS of WBL+SCBL+GL+WWL+WL in Rec-1
D OS of WBL+HBL+GL+WWL+WL in Rec-2
E CS of WBL+WL in SFL and WFL
F CS of WBL+SCBL+GL+WWL+WL in Rec-1
G CS of WBL+HBL+GL+WWL+WL in Rec-2
J Purchased caustic used in cooking in SFL and WFL
P = B + C + D
Q = E + F + G
R = A + [J x 31/40]
Loss % = ���� ��∗�����
� � ∗ 100
ORE % = 100 – Loss %
The present ORE varies between 94-95 % on a general basis for the paper plant at Abhishek
Industries.
Glossary:
Total Titrable Alkali (TTA):
Na2CO3, NaOH, Na2S
Total Active Alkali (TAA):
NaOH, Na2S
OS: Opening Stock
CS: Closing Stock
WL: White Liquor
WBL: Weak Black Liquor
SCBL: Semi-Conc. Black
Liquor
HBL: Heavy Black Liquor
GL: Green Liquor
WWL: Weak White Liquor
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2. OBJECTIVE
The objective of the project is to identify the potential sources of soda loss in the whole stream
including both pulp mill and recovery units and present some solutions for further increment in ORE.
3. PROJECT PLAN
17.05.10 -
25.05.10
• Induction programme
26.05.10 -
03.06.10
• WBL Sampling
04.06.10 -
15.06.10
• Mud Filter
16.06.10 -
24.06.10
• Pulp mill soda carryover
25.06.10 -
01.07.10
• Pulp mill Reject
02.07.10 -
08.07.10
• ESP
09.07.10 -
12.07.10
• ORE Loss data
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4. ALKALI EXIT POINTS
4.1. RECOVERY 2
Rotary Lime Kiln
Steam, 460 °C, 64 kg/cm2
Figure 4.1. Process Flow Diagram of Recovery 2
4.1.1. EVAPORATOR
Before WBL is sent to evaporation it is filtered to remove fibers (cellulose) that has come along it. It
is necessary to remove it else it will scale the evaporator. These fibers are recycled and some
amount is thrown away with some amount of Black liquor. Before feeding into evaporator WL is
added to WBL to reduce the viscosity and fraction.
LP steam is preferred in evaporators. First it’s difficult to deal with very high pressures. More
importantly latent heat, λ of steam decreases with increasing temperature or high pressure. It is
advisable to feed the steam at saturation temperature as retention time of steam in evaporator is
less and latent heat transfer is more effective.
Effects 1(A, B, C) and 2(A, B, C) have high pressure, while rest work in vacuum. Inlet temperature and
pressure of steam is 140 °C, 2.5 kg/cm2. Pressure in the last effect is 0.14 kg/cm2. It is feed backward
system of evaporator. The concentration in outlet of 3rd effect is 25% solids. Concentration in inlet of
7th effect was 10% solids. In 2nd effect concentration rises to 36% solids. In 1st effect it rises to 65-
67% solids. As there is significant change in concentration in first 2 effects there is considerable rise
in viscosity. Thus, first 2 effects are divided into 3 separate bodies. Same steam is fed in 3 bodies of
an effect, while flow of Black liquor is continuous and simultaneous. First body is called wash, second
as intermediate and third as product. Vapors from each effect sent to condenser. It contains same
amount of soda.
WBL from pulp mill
WBL Storage Tank
Evaporator, 7 effects
and 11 bodies
[10% to 65%, 170T/hr]
HBL Storage Tank
[65-67% solids]
Recovery Boiler
[Total heat transfer
area = 7283 m2]
Smelt Dissolving
tank, Green liquor
[97-102 GPL Na2O
TTA]
Causticizing
[110 MT/day] Lime Mud
WL Storage Tank
Pulp Mill
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LP Steam
Thrown Out
Washing
Figure 4.2. Evaporator Process Flow Diagram
The identified exit points of soda for permanent losses are:
a. Vibratory Screens reject
b. Vapors to Condensers
c. Washing/Scaling
d. Tank overflows
e. Seepages and Pump leakages
Figure 4.3. 7 effect-11 body Evaporator at Recovery 2 at Abhishek Industries, Dhaula complex
Black liquor
[11-12% solids]
Vibratory
Screens [5 Nos]
Fibres BL Pit
WBL Storage
Tank [3 Nos]
WWL
(to reduce
viscosity)
Evaporator
[7 effects]
Vapor to
condenser
[40 ppm] BL Pit
HBL Storage Tank
[65-67% solids] Boiler
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Figure 4.4. Condensers at Recovery 2 at Abhishek Industries, Dhaula complex
4.1.2. RECOVERY BOILER
The Recovery boiler has 3 main parts:
a. Black liquor burning and Green liquor collection
b. Flue gas flow and heat transfer
c. Demineralised and deaerated water flow and heat transfer
4.1.2.1. Black liquor firing
HBL from storage tank is preheated to reach a desired temperature of 120 °C in an indirect heater. If
indirect heater is not able to heat it, direct heater is used. The liquor stream distributes into 6
nozzles. With pressurized steam, BL is sprayed in furnace from these 6 nozzles. Initially fuel oil is
used by its own component, lignin. Green liquor falls at the bottom and is collected in Main
Dissolving Tank (MDT). It is highly concentrated and very hot at temperature of around 1000 °C.
Precautions are taken in dissolving GL. As it’s very hot direct addition of water will convert it into
steam and explode. Thus, hot water/steam jets hit the fine stream of GL falling and dilute it. Instead
of using hot water, WWL from Mud Washer 1 is used to dilute to GL that helps to maintain desired
concentration.
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MDT has outlet for vapors. The soda carryover is very limited as WWL is sprinkled at 2 points in
exiting vapors that settles solid particles in the stream.
4.1.2.2. Flue gas flow
Air is pumped in furnace at 3 levels, viz. Primary, Secondary and Tertiary. ID fan sucks the air from
furnace and pushes it through chimney. Flue gas generated on burning lignin travels through
superheaters, boiler bank and then economizer. It passes through ESP and exits from chimney top.
4.1.2.3. Water and steam system
Demineralised water is pumped in deaeration tank. The water is then pumped in economizer, then
to boiler bank and then to superheaters to produce to produce high pressure superheated steam,
which is sent to power boiler. The water from deaeration tank is passed through economizer and not
through superheaters as flue gas has enough heat to provide latent heat to water, which if otherwise
had been passed through superheaters would have extracted heat from high temperature flu gas.
Thus, final temperature of the steam would be less and exit temperature of the flue gas would be
high.
Steam
120 °C
Hot Water
Flue Gas
Steam
DM water
Chimney
Soot Blower
Figure 4.5. Recovery Boiler Process Flow Diagram
HBL Storage Tank
[65-67% solids] Indirect
heater
Direct
heater
Furnace
[6 firing guns]
3 air pumps
(Pri-Sec-Ter)
Main
dissolving tank
MDT Outlet
GL Storage
Tank
Pri - Sec -Ter
Superheaters Boiler
Bank
Economiser – 1, 2
ESP De-aeration
Tank
Stem Drum
Power
Boiler
[HP
steam,
460 °C, 63
bars]
Ash Mixing Tank
WWL
Fuel
Oil
WWL
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The identified exit points of soda for permanent losses are:
a. Flue gas carryover [ESP]
b. MDT Outlet
c. Dregs washer [Recovery 1]
d. Washing/Scaling
e. Tank overflows
f. Seepages and pump leakages
4.1.3. RECAUSTICIZING PLANT
Raw material to this unit is Green Liquor. The GL feed contains sodium carbonate in large proportion
and some amount of sodium hydroxide and sulfide. The basic reaction that occurs in a Lime slaker is:
Ca(OH)2 + Na2CO3 ↔ 2 NaOH + CaCO3
85% of equilibrium concentration is achieved in slakers. The rest is achieved in causticizers that
provide retention time for completion of reaction.
Rakes installed in clarifier and mud washers are bottleneck in the process. To prevent rake failure
automatic rake lifting mechanism is put where rakes lift automatically on reaching certain limit
loads. Rakes do not disturb the settling of suspended limestone and silica particles in clarifier and
mud washer as it rotates at speed of 7 rev/min. Its purpose is to prevent deposition at the bottom
and maintain continuous flow underflow concentrated with solids. The vacuum based rotating disk
mud filters remove calcium carbonate as mud cake. It is fed to lime kiln to produce lime. Lime kiln is
not functional at present as cost of furnace oil fed to lime kiln is higher than purchased lime. Lime
kiln is 76m long and 4m wide huge rotary kiln.
Figure 4.6. Rotary lime kiln
23 | P a g e
Agitator
Rake Steam Agitator
White liquor
clarifier
Overflow Steam Rake Overflow
Underflow Lime Mud [25 GPL as TTA as Na2O]
Washer 1
Overflow Hot Water
Underflow Rake
To Pulp Mill [5 GPL as TTA as Na2O]
LMW 2 Hot Water
Underflow
Hot Water
Overflow
Thrown Out
Limestone Lime to Lime bin
Furnace Oil
Figure 4.7. Recausticizing Process Flow Diagram
The identified exit points of soda for permanent losses are:
a. Sludge/Mud cake carryover
b. Grits and stones carryover
c. Washing/Scaling
d. Tank overflows
e. Seepages and leakages
Recovery Boiler
GL Storage
Tank [32-34%
TTA as Na2O]
GL
Heater
Slaker Rake
Classifier
Lime (Lime bin)
Grits
[Stones &
Silica]
Causticizer (4)
[100°C, each gives retention
time of 27-30 min]
WL Storage
Tank [95 GPL
TTA as Na2O]
Weak White Liquor
Storage Tank
[25 GPL as TTA as Na2O]
MDT
Lime Mud
Storage Tank
Mud Filter
(Vacuum disk filters)
[Pr = 550mmHg]
Sludge Cake
Lime Kiln
24 | P a g e
4.2. STRAW FIBER LINE (SFL)
Figure 4.8. Wet Washing in SFL
Figure 4.9. Digester in SFL
25 | P a g e
Figure 4.10. Pulp washing in SFL
Brownstock washing is a counterflow washing system with pulp and liquor stream flowing in
opposite direction. The nomenclature of washer is based on pulp flow.
The amount of water used for pulp washing is constrained at both lower and upper ends:
a. For Recovery, more water for washing implies more load on evaporator and thus higher
steam consumption. Thus, Recovery would like to reduce water content.
b. For pulp mill, more water for washing implies better washing or more soda recovery. Thus,
pulp mill would prefer high water usage.
Soda carryover in pulp has 2 major disadvantages for pulp mill:
a. Reduced paper quality, i.e. Brightness.
b. Increased use of chemicals in bleaching and further processes in paper making.
The identified exit points of soda for permanent losses are:
a. Soda carryover with pulp
b. Reject from HD cleaner
c. Reject from Delta Knotter through Vibratory Screen 1
d. Reject from Delta Screen through Vibratory Screen 2
e. Reject from Centricleaner
26 | P a g e
f. Carryover with Blow Tank vapors
g. Washing/Scaling
h. Tank overflows
i. Seepages and Leakages
Figure 4.11. Digester Feed Belt in SFL at Abhishek Industries, Dhuala complex
4.3. WOOD FIBER LINE (WFL)
The process stream for WFL is almost similar with slight modifications. WFL has 3 Batch digesters as
compared to continuous digesters in SFL. There are 5 simultaneous washers and no press. The
different in the reject streams is discussed in details later.
The identified exit points of soda for permanent losses are:
a. Soda carryover with pulp
b. Reject from Vibratory Screen
c. Reject from Pressure Screen through centricleaner and vibratory screen
d. Carryover with Blow Tank vapors
e. Washing/Scaling
f. Tank overflows
g. Seepages and Leakages
4.4. SIGNIFICANT PERMANENT LOSS POINTS
On discussion with experts, as well as workers employed in the company and on the basis of general
information derived from case studies of paper plants around the globe, significant permanent loss
points are identified as follows:
a. Mud cake carryover
b. Flue gas carryover
c. Reject streams in Pulp mill
d. Grifts and stones
e. Soda carryover with pulp
f. Carryover with Blow Tank vapors
27 | P a g e
To confirm the identified loss points, FMEA (Failure Mode Effectiveness Analysis) statistical analysis
was performed.
Experiment: FMEA on identified exit points of soda for permanent losses
Objective: To identify the significant permanent loss points
Survey Format:
FMEA on identified exit points of soda for permanent losses
Cause
No. Cause Severity Occurrence Detection RPN No.
C1 Soda carryover with pulp
C2 Mud cake carryover
C3 Reject streams in Pulp mills
C4 Flue gas carryover [ESP]
C5 Carryover with Blow Tank
vapors
C6 MDT Outlet
C7 Dregs washer [Recovery 1]
C8 Grifts and stones
C9 Seepages and Leakages at WFL
C10 Vibratory Screens reject in
Evaporator
C11 Washing/Scaling at WFL
C12 Washing/Scaling in
Recausticizing
C13 Vapors to Condensers
C14 Washing/Scaling in Evaporator
C15 Seepages and Pump leakages
in Evaporator
C16 Seepages and Pump leakages
in SFL
C17 Tank overflows in WFL
C18 Tank overflows in Evaporator
C19 Washing/Scaling in Recovery
Boiler
C20 Tank overflows in Recovery
Boiler
C21 Seepages and Pump leakages
in Recovery Boiler
C22 Tank overflows in
Recausticizing
C23 Seepages and Pump leakages
in Reausticizing
C24 Washing/Scaling at SFL
C25 Tank overflows in SFL
*Fill with 1, 3 or 9
28
| P
ag
e
Ob
serv
ati
on
ta
ble
an
d R
esu
lts:
F
ME
A o
n id
en
tifi
ed
exi
t p
oin
ts o
f so
da
fo
r p
erm
an
en
t lo
sse
s
Ca
use
No
. C
au
se
P1
P
2
P3
P
4
P5
P
6
P7
P
8
P9
R
PN
No
.
Act
ua
l
%
Cu
mu
lati
ve
%
C1
So
da
ca
rryo
ver
wit
h
pu
lp
72
9
72
9
72
9
72
9
72
9
72
9
72
9
72
9
72
9
72
9
24
.95
15
2
4.9
51
5
C2
M
ud
ca
ke c
arr
yove
r 7
29
2
43
7
29
7
29
7
29
2
43
7
29
7
29
7
29
6
21
2
1.2
55
4
6.2
06
5
C3
R
eje
ct s
tre
am
s in
Pu
lp
mill
s
24
3
72
9
72
9
81
7
29
7
29
2
43
7
29
7
29
5
49
1
8.7
90
6
64
.99
71
C4
Fl
ue
ga
s ca
rryo
ver
[ESP
] 2
43
7
29
8
1
72
9
81
7
29
7
29
7
29
7
29
5
31
1
8.1
74
6
83
.17
17
C5
C
arr
yove
r w
ith
Blo
w
Ta
nk
vap
ors
8
1
24
3
24
3
27
8
1
27
2
7
81
8
1
99
3
.38
84
8
86
.56
02
C6
M
DT
Ou
tle
t 8
1
9
81
2
43
2
43
8
1
27
2
7
3
88
.33
33
3
.02
33
9
89
.58
36
C7
D
reg
s w
ash
er
[Re
cove
ry 1
] 2
43
8
1
81
9
8
1
9
3
9
27
6
0.3
33
3
2.0
65
03
9
1.6
48
6
C8
G
rift
s a
nd
sto
ne
s 8
1
27
2
7
81
8
1
81
3
3
9
4
3.6
66
7
1.4
94
58
9
3.1
43
2
C9
Se
ep
ag
es
an
d
Lea
kag
es
at
WFL
9
8
1
9
9
24
3
3
9
3
3
41
1
.40
33
1
94
.54
65
C1
0
Vib
rato
ry S
cre
en
s
reje
ct in
Eva
po
rato
r 8
1
81
2
7
9
81
3
9
3
9
3
3.6
66
7
1.1
52
31
9
5.6
98
8
C1
1
Wa
shin
g/S
cali
ng
at
WFL
9
2
7
9
27
8
1
27
9
9
2
7
25
0
.85
56
8
96
.55
45
C1
2
Wa
shin
g/S
cali
ng
in
Re
cau
stic
izin
g 8
1
3
81
3
1
9
2
7
9
3
24
.11
11
0
.82
52
5
97
.37
97
C1
3
Va
po
rs t
o C
on
de
nse
rs
27
1
2
7
9
1
27
8
1
27
9
2
3.2
22
2
0.7
94
83
9
8.1
74
6
29
| P
ag
e
C1
4
Wa
shin
g/S
cali
ng
in
Eva
po
rato
r 2
7
27
9
2
7
27
9
2
7
3
3
17
.66
67
0
.60
46
8
98
.77
92
C1
5
See
pa
ge
s a
nd
Pu
mp
lea
kage
s in
Eva
po
rato
r
27
3
3
2
7
9
9
27
3
3
1
2.3
33
3
0.4
22
13
9
9.2
01
4
C1
6
See
pa
ge
s a
nd
Pu
mp
lea
kage
s in
SFL
3
9
3
1
2
7
3
9
9
3
7.4
44
44
0
.25
48
9
9.4
56
2
C1
7
Ta
nk
ove
rflo
ws
in
WFL
9
1
9
3
3
9
3
3
1
4
.55
55
6
0.1
55
92
9
9.6
12
1
C1
8
Ta
nk
ove
rflo
ws
in
Eva
po
rato
r 1
3
1
9
1
1
9
1
3
3
.22
22
2
0.1
10
29
9
9.7
22
4
C1
9
Wa
shin
g/S
cali
ng
in
Re
cove
ry B
oil
er
1
9
1
1
1
3
1
1
1
2.1
11
11
0
.07
22
6
99
.79
46
C2
0
Ta
nk
ove
rflo
ws
in
Re
cove
ry B
oil
er
1
1
1
1
1
1
1
1
1
1
0.0
34
23
9
9.8
28
9
C2
1
See
pa
ge
s a
nd
Pu
mp
lea
kage
s in
Re
cove
ry
Bo
ile
r
1
1
1
1
1
1
1
1
1
1
0.0
34
23
9
9.8
63
1
C2
2
Ta
nk
ove
rflo
ws
in
Re
cau
stic
izin
g 1
1
1
1
1
1
1
1
1
1
0
.03
42
3
99
.89
73
C2
3
See
pa
ge
s a
nd
Pu
mp
lea
kage
s in
Re
au
stic
izin
g
1
1
1
1
1
1
1
1
1
1
0.0
34
23
9
9.9
31
5
C2
4
Wa
shin
g/S
cali
ng
at
SFL
1
1
1
1
1
1
1
1
1
1
0.0
34
23
9
9.9
65
8
C2
5
Ta
nk
ove
rflo
ws
in S
FL
1
1
1
1
1
1
1
1
1
1
0.0
34
23
1
00
10
0
30 | P a g e
Conclusion:
The finally identified significant permanent loss points based on Perito hypothesis are as follows:
a. Mud cake carryover
b. Flue gas carryover [ESP]
c. Reject streams in Pulp mill
d. Soda carryover with pulp
Experiment 4.1. FMEA on identified exit points of soda for permanent losses
5. WBL SAMPLING
5.1. ORE FLUCTUATIONS
SRE and PME fluctuate between 80 to 120 on per day basis and thus, ORE fluctuates. With
approximately steady process, the losses are also steady. Thus, fluctuations in SRE, PME and ORE
values should be low. The reasons identified are:
a. Measurement error of WBL GPL: There is high variability in WBL GPL values. Sampling
followed is Grab sampling which doesn’t normalize these variations.
b. Increase or decrease in processed liquor: When more liquor is processed losses associated
with processing are higher, thus ORE decreases. Increase in processing liquor can be
associated with decrease in stock. Thus, when stock increases, ORE increase and vice versa.
The process streams are sampled once per shift for GPL TTA as Na2O. These values when multiplied
with the stock volumes give stock data as TTA as Na2O. The same data is used for ORE calculation.
0
20
40
60
80
100
120
0
100
200
300
400
500
600
700
800
1 2 3 4 5 6 7 8 9 1011121314151617181920212223242526
Average RPN Np.
Cumulative %
31 | P a g e
The GPL values fluctuate drastically during a shift. Thus, even small errors in measurement get
magnified when multiplied with stock values and produce incorrect SRE, PME and ORE values.
Period PME SRE ORE
Feb-09 102.69 89.58 91.99
Mar-09 96.41 93.87 90.50
Apr-09 94.93 98.55 93.55
May-09 95.33 97.86 93.29
Jun-09 98.88 94.99 93.93
Jul-09 98.64 94.53 93.24
Aug-09 108.11 85.91 92.88
Sep-09 103.6 90.62 93.88
Oct-09 101.39 93.98 95.29
Dec-09 103.04 90.5 93.25
Jan-10 103.89 91.44 95.00
Feb-10 103.26 92.29 95.30
Mar-10 97.22 97.22 94.52
Apr-10 94.77 101.29 95.99
May-10 92.49 102.42 94.73
Jun-10 88.42 106.68 94.33
Average 98.94 95.10 93.85
Coeffici
ent of
Determi
nation
0.08 0.233 0.564
Table 5.1. PME, SRE and ORE over Time
Figure 5.3. ORE versus Time plot
The low coefficient of determination, R2 values signify high unexplained variations in SRE, PME and
ORE values.
y = -0.0092x + 466.33
R² = 0.0802
0
20
40
60
80
100
120
Dec-08 Mar-09 Jul-09 Oct-09 Jan-10 May-10 Aug-10
PME
PME
Linear (PME)
y = 0.0164x - 560.5
R² = 0.2338
0
20
40
60
80
100
120
Dec-08 Mar-09 Jul-09 Oct-09 Jan-10 May-10 Aug-10
SRE
sre
Linear (sre)
y = 0.0065x - 167.26
R² = 0.5649
90.00
91.00
92.00
93.00
94.00
95.00
96.00
97.00
Dec-08 Mar-09 Jul-09 Oct-09 Jan-10 May-10 Aug-10
ORE
ORE
Linear (ORE)
Figure 5.1. PME versus Time plot
Figure 5.2. SRE versus Time plot
32 | P a g e
5.2. WBL SAMPLING
For Soda recovery unit, the minimum GPL concentration is for incoming WBL, and thus highest
volume. Also the GPL values of incoming WBL stream fluctuates heavily. Discrete sampling neglects
these fluctuations and is based on assumption of uniform flow. Under failure of such assumption,
the error is further highly magnified due to huge volumes. WBL GPL measurement was identified to
be the bottleneck in SRE and thus ORE calculation.
More frequent WBL samples were taken and analyzed with generally accepted GPL for a day to
measure the variation in total WBL TTA and thus, variation in actual ORE to calculated ORE.
Experiment: Frequent sampling of WBL from SFL and WFL for measuring TTA & RAA as
Na2O and %solids for 2 days
Objective: To study variation in WBL TTA, RAA and % solids. Analyzing effect of error in
WBL GPL value on ORE
Observation table and Results:
For WFL:
Day 1: 26th May 2010
(Na2O GPL)
Time Sample Stream % Solids RAA Factor
600 1 WFL 17.02 6 2.5
900 2 WFL 16.56 7.3 2
1030 3 WFL 16.9 7.94 1.5
1200 4 WFL 16.18 7.62 2
1400 5 WFL 15.24 7 2.5
1630 6 WFL 12.2 5.39 5.5
2200 7 WFL 15.86 7.3 8
AVG 15.2275 6.762292
STD DEV 1.55111 0.848317
Avg selected for a
day GPL 16.04 6.766667
Error (Positive)
0.8125 0.004375
Avg Stock m3
1350 1350
Total Error MT 1.096875 0.005906
With Composite sampling the error is zero
Avg for Pulp Mill 13 6
Error (Positive)
-2.2275 -0.76229
Total Error (g)
-
3007125
-
1029094
33 | P a g e
Day 2: 27th May 2010
(Na2O GPL)
Time Sample Stream % Solids RAA TTA Factor
600 1 WFL 15.8 6.6 31.7 2.5
830 2 WFL 17.57 8.25 41.98 2
1030 3 WFL 14.4 7.93 36.39 1.5
1200 4 WFL 15.7 7.61 36.81 2
1400 5 WFL 14.5 6.6 31.7 2.5
1630 6 WFL 15.07 8.56 38.75 5.5
2200 7 WFL 15.48 6.6 34.4 8
AVG
15.44229 7.353958 35.79125
STD DEV
0.986578 0.784098 3.457622
Avg selected for
a day GPL 15.26 6.6 32.6
Error (Positive)
-0.18229 -0.75396 -3.19125
Avg Stock m3
1350 1350 1350
Total Error MT
-0.24609 -1.01784 -4.30819
With Composite sampling the error is zero
Avg for Pulp
Mill 13.07 6 34.67
Error (Positive)
-2.37229 -1.35396 -1.12125
Total Error (g)
-
3202594
-
1827844
-
1513688
R² = 0.4123
R² = 0.0053
0
2
4
6
8
10
12
14
16
18
20
0 2 4 6 8
% Solids
RAA
Linear (RAA)
Linear (RAA)
34 | P a g e
For SFL:
Day 1: 26th May 2010
(Na2O GPL)
Time Sample Stream % Solids RAA Factor
600 1 SFL 11.37 7 3
900 2 SFL 11.32 7.3 1.5
1030 3 SFL 10.92 7.61 1.5
1200 4 SFL 10.81 6.98 2
1400 5 SFL 10.63 7.6 2.5
1630 6 SFL 11.18 6.66 5.5
2200 7 SFL 11.45 7.6 8
AVG 11.19813 7.239792
STD DEV 0.291906 0.350651
Avg selected for
a day GPL 11.15 7.4
Error (Positive)
-0.04812 0.160208
Avg Stock m3
3300 3300
Total Error MT -0.15881 0.528688
With Composite sampling the error is zero
R² = 0.1801
R² = 0.0042
R² = 0.004
0
5
10
15
20
25
30
35
40
45
0 2 4 6 8
% Solids
RAA
TTA
Linear (% Solids)
Linear (RAA)
Linear (TTA)
R² = 0.0066
R² = 0.0108
0
2
4
6
8
10
12
14
0 2 4 6 8
% Solids
RAA
Linear (% Solids)
Linear (RAA)
35 | P a g e
Day 2: 27th May 2010
(Na2O GPL)
Time Sample Stream % Solids RAA TTA
600 1 SFL 11.43 7 23.1
830 2 SFL 11.4 7.61 25.14
1030 3 SFL 11.06 7.3 22.75
1200 4 SFL 10.92 6.98 22
1400 5 SFL 10.29 7.3 23.1
1630 6 SFL 10.8 7.61 22.94
2200 7 SFL 12.03 7.7 24.3
AVG 11.29938 7.459583 23.47729
STD DEV 0.512186 0.275402 0.97089
Avg selected for
a day GPL 11.25 7.333333 23.5
Error (Positive)
-0.04937 -0.12625 0.022708
Avg Stock m3
3300 3300 3300
Total Error MT -0.16294 -0.41663 0.074937
With Composite sampling the error is zero
*While calculating Average GPL, weighted average is taken with weights equal to
time gap between present and next sample.
Calculation:
Considering for 27th
May, total error in Na2O TTA = -4.308 (WFL) + 0.075 (SFL) MT
= -4.233 MT
����� � ! "#$#%&#' = (3300 ∗ 23.477 + 1350 ∗ 35.791 11000 = 125.792 2�
Thus, % error in WBL received = 3.365 %
�ℎ45, % #""�" %7 89: $��$4���%�7 = �; �125.792< − ; �121.559<� �125.792 ∗ 100 = 3.5 %
R² = 0.0006
R² = 0.3019
R² = 0.0011
0
5
10
15
20
25
30
0 2 4 6 8
% Solids
RAA
TTA
Linear (% Solids)
Linear (% Solids)
Linear (RAA)
Linear (TTA)
36 | P a g e
Individual errors in WFL and SFL streams are:
SFL = 8.92 %
WFL = 0.1 %
Assuming PME as 97 %, the error in ORE = 3.4 %
Conclusion:
Very low R2 values imply the high variability in WBL streams TTA, RAA and % solids value.
Also, the analysis of error in sampling results 3.5 % in SRE and 3.4 % error in ORE. Thus, it is
immediate requirement to adopt some other sampling method for correct calculation of SRE,
PME and ORE and avoid per day fluctuations.
Experiment 5.1. Frequent sampling of WBL from SFL and WFL
5.3. COMPOSITE SAMPLING
There are different kinds of sampling methods:
a. Grab Sampling / Discrete Sampling
Advantage: Gives values of specific types of unstable parameters; No infrastructure cost
Disadvantage: For highly varying values results can be very misleading due to huge errors;
Human intervention
b. Grab and composite sampling
Advantage: Higher precision in sampling; No infrastructure cost
Disadvantage: High labor hours are required; Human intervention
c. Composite sampling
Advantage: High precision in sampling; No human intervention
Disadvantage: Moderate infrastructure cost; Issues of tank fouling
d. Automation/online analyzer
Advantage: High precision in sampling; Discrete values available instantly; Better process control
Disadvantage: High infrastructure cost
Grab sampling is presently followed by QC lab to analyze the samples. It has advantage that it gives
values of specific types of unstable parameters like temperature at a given moment of time. But as
experimental results have shown it gives large errors as fluctuations are large.
In composite sampling sample is collected continuously with constant flow rate in a collection tank
through sampling pipe. After every shift the liquor collected in sampling tank can be analyzed and
average value can be noted down.
37 | P a g e
The following design of the collection tank is proposed:
Agitator
Figure 5.4. Proposed collection tank design for WBL composite sampling
After every shift sample is collected and the tank is emptied in BL pit. It is then washed with hot
water to prevent fouling.
Advantage and disadvantage: It has a limitation that composite liquor will be cooler than current
measurement temperature i.e. 70 °C. Thus, new basis needs to be chosen. However, it has
advantage that error in measurement will be negligible. Also the tank is designed keeping in mind
the fouling problem.
Significant design parameters:
a. Hot water washing: To remove fouling due to deposition of WBL solids on cooling of WBL in
the tank, hot water washing needs to be done for few moments after draining the tank.
b. Valve head: it provides liquid for point temperature measurement.
c. Agitators: With time WBL cools and solids start settling, thus, agitation helps in maintaining
uniformity of the sample. In case, tank volume is reduced due to fouling then hot incoming
liquor will float at top and may exit from overflow without mixing, thus, agitation helps in
proper mixing.
d. Composite sampling point: It is provided at an intermediate point where concentration can
be assumed equal to general volume concentration.
e. Temperature measurement device: It helps to record temperature of inlet stream.
f. Discrete sampling point: Discrete samples can be taken, when required.
g. Overflow outlet: In case of overflow or if due to fouling inside tank volume is reduced, the
liquor flows to drain through overflow outlet.
SFL/WFL
receive
Discrete Sampling Point
Overflow
outlet
Valve head
Temp. measurement device
Hot
Water
Sampling
Point
Drain
38 | P a g e
5.4. AUTOMATION
Online analyzers can be installed at WBL stream pipes that give value of TTA, RAA, temperature etc
almost instantly.
It gives value of measured variable almost instantly and can exactly measure the total amount of
incoming black liquor as TTA. There are negligible errors and there is no human intervention.
It is suggested to have a service tank where both SFL and WFL streams mix in desired proportion.
Online analyzer measures the stream composition and helps to maintain desired flow rates to attain
desired ratio. If streams are uniform the recovery process can be standardized easily and attainable
performance can be reached. Also, operators can operate processes more uniformly as incoming
stream composition is uniform.
A list of suppliers for online Analyzers is prepared:
a. Duralyzer-NIR [Canmark]
b. Process NIR Analyzer [MODCON]
c. kajaaniALKALi Alkali analyzer [Metso]
d. Process Analytical systems
e. Online TCC/TC Analyzer [AppliTOC]
f. In-line Process Refractometer [Liquids Solids Control, Inc]
A standard of minimum deviation in WBL measurements should be targeted.
39 | P a g e
6. MUD FILTER
Figure 6.1. Lime mud filter flowsheet
6.1. LIME MUD CLARIDISC SYSTEM
Figure 6.2. Vacuum disk filter sketch Figure 6.3. Vacuum disk filter in operation
ClariDisc system consists of 3 meter diameter filter discs consisting of 18 separate sectors each
mounted on the central barrel. The sectors are made of 316L stainless steel perforated plate and
dressed with an underbag to improve liquor flow and an outer shrunk on filter bag of special
polypropylene material.
The outer layer of the cake is scrapped off the filter disc with a scrapper; the inner layer of lime mud
is retained on the filter discs to act as a filtration precoat. HiPac system breaks the precoat and helps
in its removal to prevent cake hardening.
40 | P a g e
6.2. MUD FILTER ORE LOSS
The total amount of mud cake produces is not known, but the % composition of it is known. By using
lime consumption data and % composition of mud cake, total quick lime produced can be calculated,
The Mud cake sampling is done on composite basis to minimize the errors. Lime consumption data is
taken from shift in-charge of both the units. The soda loss from Mud filters is calculated based on
these data.
Recausticizing reaction:
CaO + H2O → Ca(OH)2 [74] + Na2CO3 → CaCO3 [100] + 2 NaOH
In reaction between Ca(OH)2 and Na2CO3, Ca(OH)2 is the limiting reagent. Thus, the whole CaO that
converts to Ca(OH)2 can be assumed to convert to CaCO3.
As the concentration of impurities in mud cake is very low, the dry solids in mud cake can be
assumed to be 100% limestone.
CaO → CaCO3
Initial A 0
Final yX/100 (A – yX/100) * (100/56)
X = mass of dry solids
y = % CaO in dry mud
Now, (A – yX/100) * (100/56) = X; Thus, X can be calculated
And if z = % TTA as Na2O, Total TTA as Na2O = Zx/100
Data table 6.1, 6.2, 6.3, and 6.4 in Appendix A
The combined loss from Recovery 1 and Recovery 2 of the total soda loss through MUD CAKE in
MUD FILTER is 7.232 %.
The corresponding loss in ORE from Recovery 1 and Recovery 2 through MUD CAKE in MUD FILTER
is 0.677 %.
The combined loss from Recovery 1 and Recovery 2 of the total soda loss through GRIFTS and
STONES is 0.269 %.
The corresponding loss in ORE from Recovery 1 and Recovery 2 through GRIFTS and STONES is
0.035 %.
The combined loss from Recovery 1 and Recovery 2 of the total soda loss through MUD CAKE in
MUD FILTER and GRIFTS and STONES is 7.232 %.
The corresponding loss in ORE from Recovery 1 and Recovery 2 through MUD CAKE in MUD FILTER
and GRIFTS and STONES is 0.677 %.
A standard of 0.3% TTA as Na2O and 1% Ca(OH)2 by weight in Mud cake should be sought.
41 | P a g e
6.3. PROCESS PARAMETER TESTING
Based on information collected through journals and case studies and on discussion with experts, a
few process parameters that could affect the performance of mud filter were analyzed. The
parameters are:
a. Vacuum
b. Precoat mud cake thickness
c. Vat solid composition
d. Vat solid concentration
e. % Moisture content
f. Homogeneity in vat mixture
g. Temperature
h. Disc RPM [Retention time]
i. Pre-Scrapper washing [Displacement washing]
j. Proper disc cleaning/Disc maintenance
6.3.1. VACUUM
For proper process the pressure should be close to 550 mmHg vacuum. The vacuum is manually
controlled through vacuum pump. The pressure kept is 530-560 mmHg, which is ideal requirement.
6.3.2. PRECOAT MUD CAKE THICKNESS
Less thickness would imply better effective pressure and better moisture control. The operation is
done with mud cake thickness of 10 mm approximately. The designed value is 12 mm.
6.3.3. VAT SOLID COMPOSITION
Vat solid sampling is done to quantify the % TTA as Na2O, % CaO and % Moisture in the mud cake.
The results are discussed later. Minimum % TTA, % CaO and % Moisture are desirable.
6.3.4. VAT SOLID CONCENTRATION
In ideal condition, the vat solid concentration should be 15-18% solids. There are 3 points of dilution
of feed from Mud Washer 2. First, a hot water stream dilutes the feed to 1.12-1.13 kgpl; this is
maintained by an autovalve. Second, the hot water from HiPac system, used to scrap mud cake from
filter, dilutes vat. Third, to maintain vat level hot water dozers are placed at bottom, however, they
rarely open. Vat solid concentration sampling is done and results are discussed later.
6.3.5. % MOISTURE CONTENT
Lower the moisture implies lower the dissolved alkali content in a sample of mud cake. The %
moisture in mud filter in recovery 1 is around 50, while in recovery 2 is 45. It is considerably high and
should be reduced to 35-40%. Moisture content could be reduced by lowering disc RPM or lowering
cake thickness
42 | P a g e
6.3.6. HOMOGENEITY IN VAT MIXTURE
As pressure is uniform across disc, homogeneity of vat solution is important for uniform functioning
of disc. Vat homogeneity sampling is done and results are discussed later.
6.3.7. TEMPERATURE
Ideally, vat temperature should be 72-75 °C. Temperature results are discussed later.
6.3.8. DISC RPM
Disc RPM is kept at 85%. It could be decreased to provide sufficient time for moisture absorbance.
6.3.9. DISPLACEMENT WASHING
The rising side of the disc should be washed with hot water to facilitate displacement washing and
thus reduction content in the mud cake. Samples are taken at different flow rates of washing; results
are discussed later.
6.3.10. PROPER FILTER DISC CLEANING
As silica content is high in vat, around 8% as compared to wood based plants as 3%, choking of pores
is more frequent. Cleaning is done with hot water once in every shift. Once in every 2 or 3 weeks
cleaning is done though acid.
Experiment: Mud cake (from Mud filter of recovery 2) sampling to test % Moisture, % TTA
as Na2O and % Ca(OH)2. Grits tested for % TTA as Na2O and % Ca(OH)2.
Objective: To analyze variation in mud cake composition that could adversely affect
mud filter performance. Also, to confirm the values of % TTA for ORE
calculations
Observation table:
Time Sample W1 W2 W3 Co
de
%
Moist
ure
% TTA as Na2O % Ca(OH)2
Dry
wt m
%
TTA
Dry
wt p %
Units Hours g G g % g %
930 1MC 47.87 65.7 57.57 W 45.6 11.03 1.7 0.44 4.38 6.7 5.27
1100 2MC 49.02 71.21 61.62 5 43.21 8.32 1.4 0.45 3.79 4.5 3.84
1500 3MC 48.32 70.4 60.15 M 46.42 9.58 1.5 0.44 4.92 4.1 2.85
930 1G 49.01 103.89 93.28 N 23.97
0.32
2.02
1100 2G 50.14 69.18 65.14 E 21.22 0.93 3.2
1500 3G 47.28 71.28 65.65 3 23.47 0.91 3.4
43 | P a g e
Conclusion:
`The % TTA is around 0.45, approximately same as generally reported by QC laboratory.
However, % Ca(OH)2 value is highly different and highly varying as well. The excess presence
of lime decreases cake porosity and thus higher amount of alkali is retained in mud cake.
The inefficient process of lime addition in slaker results in highly varying concentrations of
lime in the liquor that adversely affects the performance of the Mud filter. Causticizing
control models are discussed later.
Experiment 6.1. Mud cake sampling from Mud filter of Recovery 2
Experiment: Vat and Mud sampling to test for % Solids, Twaddell, GPL TTA as Na2O, %
Ca(OH)2 and Temperature at different zones in vat and mud filter
Objective: To analyze vat solid concentration, homogeneity in vat and mud cake and
temperature of vat
Theory:
The vat samples were taken at 3 different zones from vat to check for homogeneity. Zone A is
deadzone with little turbulence, zone B is central volume, and zone C is highly turbulent just
above feed inlet.
AP BP
A C
Disk
Vat B
INLET
44 | P a g e
Observation table and Results:
Vat Homogeneity Sampling
Time Sample % Solid Twaddell TTA
(Na2O GPL)
Ca(OH)2
(%)
Temp
(°C)
Avg %
Solid
1045 A1 12.42 18 1.84 3.23
65 13.83 1045 B1 15.69 24 2.27 2.15
1045 C1 13.4 19 1.97 2.55
STD DEV 12.12 15.80 10.88 20.65
1300 A2 19.57 24 2.46 1.61
65 26.57 1300 B2 29.34 26 2.4 1.42
1300 C2 30.81 22 2.4 1.42
STD DEV 22.99 8.3 1.43 7.39
1600 A3 23.36 27 2.21 2.02
64 21.68 1600 B3 21.05 26 2.77 1.55
1600 C3 20.64 27 2.58 1.9
STD DEV 6.76 2.16 11.30 13.39 31.04
Mud Cake Homogeneity
Time Sample % Moisture TTA, % Na2O
1045 AP1 41.88 0.347
1045 BP1 42.73 0.357
STD DEV 1.42 2.00
1300 AP2 46.7 0.483
1300 BP2 49.96 0.447
STD DEV 4.76 5.47
0
10
20
30
40
0 2 4
Sample 1
Sample 2
Sample 3
% Solid
0
1
2
3
4
0 2 4
Sample 1
Sample 2
Sample 3
% Ca(OH)2
0
0.5
1
1.5
2
2.5
3
0 2 4
Sample 1
Sample 2
Sample 3
TTA (GPL)
45 | P a g e
Conclusion:
a. The % Solid variation is huge. It should remain between 15-20 % for proper moisture
absorbance.
The last 2 observations were taken with autovalve maintaining density of 1.135 kgpl,
and first observation was taken with 1.12 kgpl.
Density (solid phase) of limestone = 2.25 gcm-3
; thus, K = 1.8
Thus, for 1.135 kgpl, %Solid = 21.41 % & for 1.12 kgpl, % Solid = 19.28 %
b. There is contrasting difference in concentrations at different zones in vat and mud cake.
The difference in vat concentration result in non-uniform mud cake formation on mud
filter and thus, performance of the filter suffers. However, the deviations are minimized
over mud cake as disk passes through huge volumes. The %Standard Deviations are
calculated that give standard deviation over average of that quantity. A proper agitation
system needs to be installed to maintain homogeneity and reduce alkali loss. Such
system is installed in Drum filter of Recovery 1.
c. The temperature of vat solution is 65 °C, but it should be 72-75 °C.
The feed to the Mud filter is received from LMS tank, which is dozed by hot water to
maintain required density. LMS tank has supply of steam from power boiler (Pr. 4.55
atm and temp. 150 °C). With complete opening of steam valve the temperature inside
LMS tank is 70 °C, thus it cannot be further increased. There is no steam line in Mud
filter. The hot water is received from evaporator at approximately 67-70 °C. The reason
of loss in temperature from LMS to vat is due to presence of no insulation of feedline to
Mud filter. By providing insulation temperature can be kept at around 70 °C.
41.8842.73
46.7
49.96
40
42
44
46
48
50
52
0 1 2 3
Sample 1
Sample 2
0.347 0.357
0.4830.447
0
0.1
0.2
0.3
0.4
0.5
0.6
0 1 2 3
Sample 1
Sample 2
> = ? @@ − 1A @ = '#75%�B �C 5��%' Dℎ�5#
Glossary:
Twaddell: It helps to measure density instantly. To convert °Tw to kg/l or gcm-3
, remove the
decimal and 1 before it. Multiply the rest with 2. E.g. 1.12 kg/l = 24 °Tw.
% Solid
and Density: 8 % 8��%' = > �E�FE � G = '#75%�B, HI
J
Experiment 6.2. Vat and Mud sampling to test homogeneity from Mud filter of Recovery 2
46 | P a g e
A washer system is installed in the mud filter that is used to clean the disk. The same washer can be
used with less flowrate during process for displacement washing. The experiment was conducted
with different flowrates of washing.
Experiment: Calculation of % TTA as Na2O at different flowrates of washing
Objective: To analyze effect of displacement washing on Mud cake at different
flowrates of washing
Observation table and Results:
Day 1
Sample Flowrate
(%)
%
Moisture
TTA
(NA2O
%)
%
Reduction
Cumulative
% Reduction
A1 0 50.63 0.543
A2 20 48.97 0.34 37.39 37.38
Day 2
Sample Flowrate
(%)
%
Moisture
TTA
(NA2O
%)
%
Reduction
Cumulative
% Reduction
B1 0 48.58 0.796
B2 10 48.76 0.442 44.47 44.472
B3 20 48.54 0.478 39.94 -8.14
B4 30 48.41 0.486 38.94 -1.67
B5 40 48.28 0.423 46.85 12.96
Day 3
Sample Flowrate
(%)
%
Moisture
TTA
(Na2O %
)
%
Reduction
Cumulative
% Reduction
C1 1 43.52 0.61
C2 10 43.71 0.51 16.39 16.39
C3 20 45.76 0.55 9.83 -7.84
C4 30 46.78 0.5 18.03 9.09
C5 40 47.4 0.56 8.19 -12
47 | P a g e
*Composite sampling is done to minimize variation due to non-homogeneity.
Conclusion:
There is considerable reduction in alkali content on displacement washing. However, the
curve is not linearly decreasing as assumed; thus, there is no considerable difference on
increasing the flowrate. There is no major difference in % Moisture content of mud cake on
washing, thus, most of the water reabsorbed by mud cake is extracted back with filtrate.
The effects of displacement washing can be increased by increasing the porosity of the cake.
Lime mud cake has very less porosity and thus, displacement washing is not much effective.
Considerable decrease in moisture content on displacement washing can be achieved by
using Filter Aids. Principle types of Filter Aids include Diatomaceous Earth (DE), Perlite,
cellulose and Rice hull ash. Each type has its own characteristics, advantage and
disadvantages. NALCO supplies filter aids for mud washing in lime mud filters with a product
code NALCO 7560. It is a surfactant based filter aid, which is currently used by BILT and ITC.
The feed is very small as 200g/T i.e. 0.02% by wt. Thus, there is no increase in impurity of
mud cake. Also it evaporates at 800 °C and thus, will not stick on walls of lime kiln, if
operated.
Experiment 6.3. Displacement washing in mud filter of Recovery 2
48.58
48.76
48.54
48.41
48.2848.2
48.4
48.6
48.8
0 20 40 60
% Moisture - B
% Moisture
0.796
0.442 0.478 0.4860.423
0
0.2
0.4
0.6
0.8
1
0 20 40 60
% TTA Na2O - B
% TTA
0.610.51 0.55
0.50.56
0
0.2
0.4
0.6
0.8
0 20 40 60
% TTA Na2O - C
% TTA
43.5243.71
45.76
46.7847.4
43
44
45
46
47
48
0 20 40 60
% Moisture - C
% Moisture
48 | P a g e
6.4. CAUSTICIZING CONTROL MODELS
In the slaker the amount of lime to be added depends upon causticizing efficiency required and feed
TTA (as Na2O). Presently, the operator measure the °Tw in inlet GL and keeping the °Tw difference to
a certain value depending upon GL TTA in slaker outlet, adds lime. The lime addition is manually
controlled and temperature variation provides information to operator when to stop adding further
lime.
GL TTA °Tw difference
92-93 8
85-86 9-10
The objective is to maintain TAA above 80. But causticizing efficiency is compromised and this leads
to excess lime addition in the system.
6.4.1. CAUSTICIZING EFFICIENCY
TTA is measured in lab once in 2 hours (as done presently). TTA and density (Twaddell) are used to
calculate a conversion factor for converting TTA values into density (Twaddell) and vice versa. The
conversion factor is calculated form results in the previous 8 or 24 hours. Now, based on Goodwin’s
curve the degree of causticizing is decided. The sulfidity can be taken as 5% (based on general
observation).
TTA (Na2O GPL) 80 85 90 95 100 105
CE% 89 88 87 87 86 85
The NaOH (GPL Na2O) can be related to continuous temperature difference measurement and
density (Twaddell) measurement, verified by titration results.
6.4.2. GREEN LIQUOR CONTROL AND CAUSTICIZING CONTROL
In this model the incoming GL is made uniform by WWL dozing. The TTA is maintained at around 85
GPL as Na2O. The corresponding CE% is 88 and NaOH GPL as Na2O is 70. Particular lime feeding rate
can be noted based on temperature and density. Uniform lime feeding needs to be done.
6.4.3. ADVANCED CAUSTICIZING CONTROL WITH KAJAANI ALKALI
In causticizing control there are 2 different control loops, GL TTA control and WL CE% control. GL
TTA control stabilizes the TTA value of GL flowing to the slaker. WL CE% control stabilizes the
causticizing degree of produced white liquor. The CE% of lime milk is used as a short feedback signal
to the dT controller.
Recovery 2 doesn’t have a proper lime feeding system and it’s presently manually controlled. In
order to switch on to advanced control, the feeding system needs to be automated as well.
Metso Kajaani Causticizing Control and Kajaani Alkali Analyzers are 2 such causticizing control
models supplied by Metso.
49 | P a g e
7. PULP MILL SODA CARRYOVER
7.1. PULP MILL SODA CARRYOVER ORE LOSS
Data table 7.1, 7.2 and 7.3 in Appendix A
The loss through SODA CARRYOVER WITH PULP in SFL from total soda losses is 36.75 %.
The loss through SODA CARRYOVER WITH PULP in WFL from total soda losses is 32.84 %.
The corresponding loss in ORE in SFL as SODA CARRYOVER WITH PULP is 4.975 %.
The corresponding loss in ORE in WFL as SODA CARRYOVER WITH PULP is 5.427 %.
The combined loss through SODA CARRYOVER WITH PULP in SFL and WFL from total soda losses is
69.59 %.
The corresponding loss in ORE in SFL and WFL as SODA CARRYOVER WITH PULP is 5.108 %.
The losses from Soda carryover with pulp in SFL and WFL lines are huge and solutions must be
sought for reduction in these losses. The solutions are discussed later in this section
A standard of 8-10 kg/MT of TTA as Na2O as soda carryover with pulp in both SFL and WFL
individually needs to be targeted.
50 | P a g e
7.2. PULP MILL PRODUCTION VERSUS SODA CARRYOVER LOSSES
Soda carryover as kg/MT TTA as Na2O for WFL is very high. It is suggested that as the WFL production
has increased, Soda carryover as kg/MT has also increased manifold. Soda carryover versus
Production curves are plotted for SFL and WFL and their relationship is studied.
Data table 7.4 and 7.5 in Appendix A
For WFL,
Figure 7.1. Production versus Time in WFL
Figure 7.2. Soda carryover as kg/MT of unbleached pulp versus Time in WFL
y = 0.5626x - 21966
0
200
400
600
800
1000
03-Dec 22-Jan 13-Mar 02-May 21-Jun
Production
Production
Linear (Production)
y = 0.0859x - 3437.6
0
5
10
15
20
25
30
03-Dec 22-Jan 13-Mar 02-May 21-Jun
Soda carryover
Soda carryover as kg/MT
Linear (Soda carryover as
kg/MT)
51 | P a g e
Figure 7.3. Production and Soda carryover versus Time in WFL
Figure 7.4. Soda carryover versus Production in WFL
y = 0.5626x - 21966
y = 0.0859x - 3437.6
0
5
10
15
20
25
30
0
100
200
300
400
500
600
700
800
900
03-Dec 22-Jan 13-Mar 02-May 21-Jun
Weekly Production
Soda Carryover as
kg/MT
Linear (Weekly
Production)
Production and Soda Carryover
y = 0.0301x - 2.0499
R² = 0.1547
0
5
10
15
20
25
30
35
40
45
50
500 550 600 650 700 750 800
Soda Loss vs Production
% Soda Loss vs Production
Linear (% Soda Loss vs
Production)
52 | P a g e
For SFL,
Figure 7.4. Production versus Time in SFL
Figure 7.5. Soda carryover as kg/MT of unbleached pulp versus Time in SFL
y = 1.2705x - 49723
0
200
400
600
800
1000
1200
1400
1600
1800
03-Dec 22-Jan 13-Mar 02-May 21-Jun
Production
Production
Linear (Production)
y = -0.0013x + 68.687
0
5
10
15
20
25
30
35
40
03-Dec 22-Jan 13-Mar 02-May 21-Jun
Soda carryover
Soda carryover as kg/MT
53 | P a g e
Figure 7.6. Production and Soda carryover versus Time in SFL
Figure 7.8. Soda carryover versus Production in SFL
A standard of constant soda carryover with production is targeted.
y = 1.2705x - 49723
y = -0.0013x + 68.6870
5
10
15
20
25
30
35
0
200
400
600
800
1000
1200
1400
1600
1800
03-Dec 22-Jan 13-Mar 02-May 21-Jun
Production
Soda Carryover as kg/MT
Linear (Production)
Production and Soda Carryover
y = -0.0009x + 17.369
0
5
10
15
20
25
30
35
40
500 700 900 1100 1300 1500 1700 1900
Soda Loss vs Production
% Soda Loss vs Production
Linear (% Soda Loss vs
Production)
54 | P a g e
Observation (WFL):
The production has risen over last few months but soda loss as kg/MT has also risen very swiftly over
the same period.
Observation (SFL):
There has been an increase in production, but the soda loss has remained constant over the same
period.
Conclusion:
As soda loss as kg/MT is rising with production, it shows the maximum capable load of washers has
been reached. Further increase in production affects the washer performance. It is necessary that
steps should be taken to improve the efficiency of washers to make them capable of handling the
increased load. Else, new washers need to installed in the process line to reduce the load on
individual washers.
On the other hand, for SFL, the operation is within the maximum capable load of washers and even
an increase in production doesn’t affect the washers’ performance.
7.3. WASHER EFFICIENCY FOR SFL AND WFL
Figure 7.9. Brown Stock Washer
55 | P a g e
Presently, Soda carryover as kg/MT of unbleached pulp TTA as Na2O for SFL is around 15 and for WFL
is around 24. It is necessary to further reduce the soda loss as it contributes approximately 70% to
the total soda loss in the system. Various steps can be taken to reduce soda loss from washers.
Presently 2 projects are going on, one in each, in SFL and WFL to reduce soda loss by increasing the
efficiency of washers. Solutions given in WFL are maintaining proper vat concentration, proper
nozzle (for displacement washing) flow rate, maintenance of nozzles and proper vacuum. In SFL, the
project is focused on increasing the vacuum in the washers, which are inefficient presently.
7.3.1. TOTAL WASHABLE ALKALI AS SODA CARRYOVER IN WFL
It was suggested that the increase in loss in WFL is due to increase in bound soda loss and it cannot
be retrieved. Elemental analysis of washed pulp is conducted to calculate washable alkali in the
sample. Thus, % of bound alkali to total alkali is calculated.
Experiment: Elemental analysis of filtrate of thoroughly washed pulp from final washer in
WFL to calculate total washable alkali as kg/MT of dry unbleached pulp TTA
as Na2O.
Objective: To calculate total washable alkali in a sample of pulp from final washer
Observation table and Results:
Sample Wet
Wt
Dry
Wt
Vol. of
Solution Density
Wt. of
solution Na TWA
PPM g as
Na2O
kg/MT TTA
as Na2O
g g ml g/ml g
TWA1 10.701 1.626 1000 0.9758 975.48 15.8 0.0154 0.0208 14.79
Total soda carryover as kg/MT TTA as Na2O for same sample is 24.19 and % Moisture is 84.8.
Thus, % washable alkali = 62.87 of total soda carryover in unbleached pulp.
Conclusion: A large percentage of total soda carryover in unbleached pulp is washable
and can be retrieved.
Experiment 7.1. Analysis of total washable alkali in washed pulp in WFL
56 | P a g e
8. PULP MILL REJECT
8.1. PULP MILL REJECT ORE LOSSES
8.1.1. TOTAL SODA LOSS CALCULATIONS
To calculate soda losses from pulp mill reject the amount of reject and its composition is required to
be known.
There are 3 reject streams in SFL. The total reject is 1.2 % of unbleached pulp. The ratio of reject
from these exit streams is:
Screen 1 (Thick mesh) : Sand Box : Screen 2 (Thin) = 0.35 : 0.15 : 0.50
There are 2 reject streams in WFL. The total reject is 1 % of unbleached pulp. The ratio of reject from
these exit streams is:
Vibratory Screen (Thick) : Pressure Screen (Thin) = 0.42 : 0.58
Samples were collected from the reject streams in SFL and WFL respectively with weights from
different streams in the ratio of their reject ratio.
Experiment: Reject stream analysis for TTA as Na2O in kg/MT of dry sample rejected
Objective: To calculate TTA as Na2O in kg/MT for ORE loss calculation
Observation table and Results:
For SFL,
Sample % Moisture TTA (as Na2O in kg/MT)
Wet wt Dry wt m TTA
% g g ml kg/MT
D11 82.29 11.988
6.8 49.2
D12 82.77 11.405 7.2 56.27
D21 80.72
1.381
52.79
D22 81.31 3.221 52.76
For WFL,
Sample % Moisture TTA (as Na2O in kg/MT)
Wet wt Dry wt m TTA
% g g ml kg/MT
D11 68.71 8.32
13.56 80.06
D12 63.02 7.97 16.10 83.95
D21 64.10
4.597
52.79
D22 68.21 2.068 52.76
TTA as Na2O in kg/MT for SFL is 52.76 and for WFL is 81.82.
Experiment 8.1. Reject stream analysis for TTA in WFL and SFL
57 | P a g e
8.1.2. TOTAL WASHABLE SODA LOSS CALCULATIONS
Experiment: Elemental analysis of filtrate of thoroughly washed pulp from reject streams
to calculate total washable alkali as kg/MT of dry unbleached pulp TTA as
Na2O.
Objective: To calculate total washable alkali in a sample of pulp from reject stream
Observation table and Results:
A B C D H I E F G
Sampl
e
Wet
wt
Sol.
Density
Sol.
Wt
Dry
wt Na
Na as
Na2CO3
Na as
Na2O
%
Moist
TWA as
Na2O
TWA
avg
Unit g g/ml g g PPM g g g % kg/MT kg/MT
Form
ula
100
0*B
H*
(C/10
^6)
I*(53/2
3)
I*(31
/23)
[1-
(D+E)
/A]*1
00
[F/(E+D)
]*1000
S Thick
1 9.096 0.966 966 1.042
117.
6 0.114 0.262 0.153 85.65 117.440
50.990 S Thin
1 20.026 0.952 952 5.429
120.
4 0.115 0.264 0.154 71.57 27.136
WThic
k 1 11.079 0.97 970 2.404 238 0.231 0.532 0.311 73.5 105.981
55.3 W Thin
1 7.676 0.968 968 1.922 28.9 0.028 0.064 0.038 74.13 18.981
S Thick
2 10.616 0.963 963 1.112
178.
6 0.172 0.396 0.232 82.73 153.690
50.82 S Thin
2 8.381 0.978 978 2.213 46.3 0.045 0.104 0.061 76.32 26.337
WThic
k 2 9.612 0.979 979 2.118
178.
1 0.174 0.402 0.235 68.28 93.265
57.28 W Thin
2 14.781 0.959 959 2.927 52.6 0.050 0.116 0.068 69.71 22.345
*For average TWA, the weights are taken as equal to reject ratio.
Conclusion:
Assuming the total soda content same as for previously done sampling, % Soda as washable with
respect to total soda are:
SFL: 96.54%
WFL: 68.96%
58 | P a g e
Thus, a large fraction of soda rejected in the reject stream can be retrieved by hot water washing.
Assuming that we can retrieve 50% of washable alkali content, then we soda washable in SFL is
24.45 kg/MT and in WFL 28.145 kg/MT.
Thus, % alkali retrieved of total alkali content is:
SFL: 48.27%
WFL: 34.48%
Average pulp loss through reject in MT (from June 1 to June 17):
SFL: 2.369 MT
WFL: 1.399 MT
Thus, % Alkali that can be retrieved,
= (48.27 ∗ 2.369 + 34.48 ∗ 1.399 12.369 + 1.399
= 43.15 %
Thus, Reduction in ORE,
= (0.4315) * 0.201
= 0.087 %
Or, New ORE loss,
= 0.114 %
Experiment 8.2. Analysis of total washable alkali in pulp from reject stream in WFL and SFL
Based on above data, ORE losses are calculated for Reject stream in SFL and WFL.
Data table 8.1 and 8.2 in Appendix A
The total soda loss as SODA CARRYOVER WITH REJECT in SFL and WFL from total soda losses is 2.81
%.
The corresponding total soda loss in ORE as SODA CARRYOVER WITH REJCT in SFL and WFL is 0.201
%.
The total washable soda loss as SODA CARRYOVER WITH REJECT in SFL and WFL from total soda
losses is 2.34 %.
The corresponding total washable soda loss in ORE as SODA CARRYOVER WITH REJCT in SFL and
WFL is 0.167 %.
A standard of reduction of loss in ORE from Reject to 0.1 % should be set.
59 | P a g e
8.2. REJECT STREAM WASHING
The reject streams in SFL and WFL are thoroughly studied and measures are suggested to decrease
soda loss. To reduce washable soda loss in reject stream principle solutions are hot water alkali
washing and pressure drying for reduction in moisture content.
The devices related to reject stream in SFL line are HD (High density) Cleaner, Delta Knotter, Delta
Screen, Opti Screen, Centricleaner and Vibratory Screen. The devices related to reject stream in WFL
line are Vibratory Screen, Pressure Screen and Centricleaner.
For SFL,
Pulp + liquor
Liquor for dilution Reject
[Sand]
Accept
Liquor for dilution Accept
Liquor for washing Reject
Accept Reject [Wood chips, uncooked waste]
Figure 8.1. HD Cleaner, Delta Knotter and Vibratory Screen in SFL
HD Cleaner is a centrifugation based filtering device similar to cyclone separator but for liquids. High
density sand is settled at bottom and accept comes from top. In the system as there is no pressure
drying moisture content is very high in reject and thus soda content is high. Also, concentrated
liquor of Filtrate tank 1 is used which has highest BL content of all Filtrate tanks.
Delta Knotter has pressure screens. High pressure difference in inlet and outlet pushes material
through the screen. Again, washing is done with liquor from Filtrate tank 1.
Vibratory Screen [Delta Knotter stream] receives reject from Delta Knotter, where vibratory action
filters the pulp. The reject falling down is washed with liquor from Filtrate tank 1 that increases
moisture and alkali content of the reject.
Blow tank
HD Cleaner Filtrate tank 1
[Conc. WBL]
Delta Knotter
Sand Box
(Mixed with Reject
from Centricleaner and
thrown out)
Vibratory Screen
[Thick mesh]
Thrown
out
Washer 1 & 2
Accept tank
Blow tank
60 | P a g e
Figure 8.2. HD cleaner Figure 8.3. Delta Knotter Figure 8.4. Vibratory Screen
Accept
Liquor for dilution Accept
Liquor for dilution Reject
Liquor for dilution Accept [Sand] Reject
Reject
Liquor for washing Accept
Reject [Shives]
Figure 8.5. Delta Screen, Opti Screen, Centricleaner and Vibratory Screen in SFL
Delta Screen and Opti Screen are similar to Delta Knotter but the screens are thin. Also, a pressure
plug, moved by a rotor pushes material through screen. The outlet is dry but the moisture content is
increased on washing at Vibratory Screen.
Centricleaner is based on principle same as cyclone separator. In the 4 units, pulp and paper flow
counter wise.
Press 1
Low Consistency Tank
Delta Screen
Filtrate tank 3 Opti Screen
Centricleaner
[Pri-Sec-Ter-Quar]
Delta Thickener
Sand Box LC tank
Vibratory Screen
[Thin mesh] Dump tank
Thrown
out
61 | P a g e
For WFL,
Liquor for washing Accept
Reject [Uncooked waste]
Figure 8.6. Vibratory Screen in WFL
The alkali content in reject from vibratory screen is very high as there is no washing or pressure
drying.
Figure 8.7. Centricleaner Figure 8.8. Delta Screen Figure 8.9. Pressure Screen
Liquor for washing Accept
Reject
Reject
[Shives]
Figure 8.10. Pressure Screen, Centricleaner and Vibratory Screen in WFL
Blow tank
Vibratory Screen Filtrate tank 1
[Conc. WBL]
Thrown
out
Washer 1
Washer 3
Pressure Screen Filtrate tank 4 Washer 4
Dilution tank Centricleaner
[Pri-Sec-Ter-Quar]
Vibratory Screen Thrown
out
62 | P a g e
Solutions suggested to reduce alkali loss from reject stream are:
a. Hot water header for washing
Instead of using liquor for washing the pulp in Vibratory Screens and especially liquor from Filtrate
tank 1, a common hot water header can be made that takes its feed from hot water tank used to
wash pulp in final washer or press. To avoid increase in hot water consumption and black liquor
dilution, the Accept can be fed back to the hot water tank.
Hot Water Hot water for washing
Header
Accept
Figure 8.11. Hot water header for washing
b. Parallel cleaning in Centricleaner
Presently, flow in centricleaner bodies is anti-parallel. The liquor in the first stage gets highly
concentrated. To incorporate soda washing in the process, a system of parallel flow of liquor into the
different bodies can be provided.
c. Pressure filter dryer
A pressure filter dryer can be installed common to both SFL and WFL. In these dryers, the reject
streams are first washed with hot water. They are then dried by applying pressure. Thus maximum
washable alkali can be extracted.
The required size of such dryers is less considering the load. Thus, the capital cost is not too high.
Further, depending upon the extent of alkali washing, best suitable size can be selected. Some of the
suppliers of such filters are:
a. 3Di Equipment Ltd
b. Dhananjaya Global Business Solutions
c. GEA Barr-Rosin Inc.
d. Aeroglide Corporation
e. MET-CHEM Inc.
f. Bhagwati Machines India Pvt Ltd
g. Arjun Technologies (I) Ltd
Hot water tank
Vibratory Screen
[Thin mesh]
Vibratory Screen
[Thick mesh] Sand Box
63 | P a g e
9. ESP – ELECTROSTATIC PRECIPITATOR
ESP PHOTO!!
Figure 9.1. ESP
Electrostatic precipitator (ESP) essentially consists of 2 sets of electrodes, viz. collecting electrodes
and emitting (discharge) electrodes. These two electrodes are arranged in alternate rows. A
unidirectional high voltage from a rectifier is applied between these 2 electrodes, connecting its
negative polarity to the emitting electrodes and the positive polarity to the collecting electrodes
which are earthed.
Because of physical configuration field in the neighborhood of the emitting electrode is very high.
The dust laden flue gas from boiler passes between rows of collecting and discharge electrodes. The
gas molecules which are normally neutral are ionized due to the presence of high electric field. The
positive charges of the ions created travel towards the discharge electrodes and the negative
charges (ions and electron) towards the collecting electrodes.
On the way to the collecting electrode, the negative charges get attached to the dust particles. Thus
the dust particles are electrically charged. In the presence of high electric field between emitting and
collecting electrodes the charged dust particle experience a force which causes the particles to move
towards the collecting electrodes and finally get deposited on them.
A minor portion of dust particles which have acquired positive charges get deposited on the emitting
electrodes also. Periodically these particles are dislodged from the electrodes by rapping the
electrodes. The particles then fall into the bottom from where they are removed by the ash deposal
system.
64 | P a g e
Various parts of the precipitator are:
a. Precipitator chamber
b. Discharge system
c. Collecting system
d. Gas distribution system
e. Dust conveying system
f. Flue gas valve
g. Rectifier-Transformers
9.1. BHEL ESP SYSTEM
Design Parameter Design Value Unit
Gas Flow rate 31.45 m3/s
Inlet Temperature 170 °C
Inlet dust concentration 16 g/Nm3
Outlet dust concentration 75 mg/Nm3
ESP efficiency 99.53 %
No. of fields in series 3 Units
Press. drop across precipitator 25 mmWC
Gas velocity (inside ESP) 0.66 m/s
Treatment time 14.65 s
No. of collecting electrode in a
row in a field 8 Units
No. of rows of CEs per field 25 for field 1 and 21 for field 2
and 3 Units
Specific collection area 97.68 s/m
Table 9.1. BHEL ESP Design Conditions
65 | P a g e
9.2. PROCESS PARAMETERS
The parameters are divided as constant and variable parameters based on the scope of variation in
their values in the installed ESP at Recovery unit in Abhishek Industries.
Constrained/constant parameters are:
a. Aspect ratio; Height, length and spacing of collection plate i.e. crossection area of ESP
b. Diameter of entering particles
c. Gas uniformity/Gas distribution
d. No. and type of discharge electrodes and collection plates
e. Sneakage
f. Particulate size distribution
Variable parameters are:
a. Gas flow rate; Treatment time; Velocity
b. Temperature
c. Moisture
d. Gas composition [Flue gas conditioning]
e. Gas viscosity
f. ESP ash composition
g. Peak Voltage; Spark rate; Energization
h. Pressure drop
i. Resistivity
j. Re-entrainment
k. Specific Collection Area
l. Inlet dust load
m. Effectiveness of dust removal system
Many of the above mentioned parameters are inter-related. All the parameters can be reduced to 5
basic variables:
a. Collection Efficiency
Theoretical collection efficiency is given by Matts-Ohnfeldt equation6,
6 Rose, H. E., and A. J. Wood. An Introduction to Electrostatic Precipitation in Theory and Practice
66 | P a g e
Or,
Certain values like particle size distribution and gas viscosity could not be calculated, thus,
theoretical collection efficiency could not be calculated.
Practical collection efficiency is calculated from inlet dust concentration and outlet dust
concentration of an ESP under process.
Practical Collection Efficiency,
= MNJOP QRSP TUNTONPVWPXUN�YRPJOP QRSP TUNTONPVWPXUNMNJOP QRSP TUNTONPVWPXUN *100
Practical Collection Efficiency calculations are done and results are discussed later.
b. Resistivity
Resistivity, which is a characteristic of particles in an electric field, is a measure of a particle's
resistance to transferring charge (both accepting and giving up charges). Resistivity is a function of a
particle's chemical composition as well as flue gas operating conditions such as temperature and
moisture. Particles can have high, moderate (normal), or low resistivity7.
7 Rose, H. E., and A. J. Wood. An Introduction to Electrostatic Precipitation in Theory and Practice
67 | P a g e
Table 9.2. ESP characteristics with Resistivity; Source: Adapted from U.S. EPA 1985
Fly ash from Recovery boilers tends to have a good resistivity. The reason for this good resistivity
comes from the chemistry of the process. Typical alumina (Al2O3) and silica (SiO2) content (which are
poor electrical conductors) is high. Also since combustion is commonly done with a wet fuel in a
mass type firing mode, it typically generates a higher level of conductive carbon in the ash. Lastly,
the surface moisture of the fuel and inherent hydrogen in cellulose, cause the flue gas to have
appreciable moisture (typically 15-25%). This flue gas moisture tends to give some "surface
conditioning", or a conductive liquid film to the particulate. These factors result in "good" resistivity
for ESP ash8.
Resistivity measurements could not be done in laboratories of the company. The company can send
sample for resistivity to some other labs which will provide important information on flue gas
characteristics. Also, the reason of ash build up on ESP and frequent conveyor failures can be high
resistivity of ESP ash that means high cohesivity. Thus, the correct reason for current problems in
ESP can be known.
8 Prakash H. Dhargalkar, Jose Astolphi, Jr. Advancements in air pollution control for pulp and paper industry
68 | P a g e
c. Specific Collection Area (SCA)
The specific collection area (SCA) is defined as the ratio of collection surface area to the gas flow rate
into the collector.
Most conservative designs call for an SCA of 20 to 25 m2 per 1000 m3/h to achieve collection
efficiency of more than 99.5%.
Total collection area in Recovery 1 = 3276.8 m2 [(48*8*0.4*8) + 2*(40*8*0.4*8)]
d. Aspect Ratio
Aspect ratio relates the length of an ESP to its height and is an important factor in reducing rapping
loss (dust re-entrainment).
Aspect ratios for ESPs range from 0.5 to 2.0. However, for high-efficiency ESPs (those having
collection efficiencies of > 99%), the aspect ratio should be greater than 1.0 (usually 1.0 to 1.5).
For Recovery 1,
Length of each plate = 0.4 m
No. of plates in each field = 8
Thus, total length of plates in each field = 3.2 m
No. of fields = 3
Thus, total length of plates = 9.6 m
Thus, Effective length = 9.6 m
Effective height = 8 m
Thus, AR = 9.6/8 = 1.2
e. Corona Power
The corona power is the power that energizes the discharge electrodes and thus creates the strong
electric field. A strong electric field is needed for achieving high collection efficiency of dust particles.
69 | P a g e
The following values are recorded for Recovery 1 and 2:
For Recovery 1,
Field Peak Voltage
(Supplied) [kV]
Average Voltage
[kV] Current [mA]
Corona Power,
Pc [kW]
1 65 50 80 4
2 65 50 100 5
Table 9.3. Corona power of ESP of Recovery 1
*The values are taken normal performance; ESP at Recovery 1 is producing less corona power most
of the time
For Recovery 2,
Field Peak Voltage
(Supplied) [kV]
Average Voltage
[kV] Current [mA]
Corona Power,
Pc [kW]
1 65 62 53 3.286
2 95.5 83.6 154 12.874
3 55 45 250 11.250
Table 9.4. Corona power of ESP of Recovery 2
For Recovery 1, total Pc = 9.00 kW
For Recovery 2, total Pc = 27.41 kW
The corona power generated in Recovery 1 and Recovery 2 at normal conditions is close to ideal
values. However, as mentioned ESP of Recovery 1 often produces reduced Corona power and thus
its performance is adversely affected.
f. Dust dislodging system
Dust build up on collection plate reduces corona power of the field and sometimes lead to back
corona, further reducing electric field strength.
With the installment of Alstom controller for rapping, dust dislodging is highly improved. The
problem of inefficient performance of ESP and frequent failures of conveyor belt was supposed to be
due to rapping problems.
70 | P a g e
9.3. Collection Efficiency
Practical Collection Efficiency,
= MNJOP QRSP TUNTONPVWPXUN�YRPJOP QRSP TUNTONPVWPXUNMNJOP QRSP TUNTONPVWPXUN *100
The outlet dust concentration is taken from flue gas analyzer. For inlet dust concentration, an
experiment is performed on Ash mixing tank.
Experiment: For Recovery 2, density of AMT is noted at different time intervals with ESP
ash falling rate as the only variable and rest as constants. Gas flowrates are
noted down for different sampling periods.
Objective: To calculate rate of ash collected in ESP through sampling AMT density. With
known gas flowrate practical collection efficiency is calculated.
Procedure:
To calculate inlet dust concentration, two parameters can be evaluated – ash collection rate
and inlet gas flow rate. The ratio of Ash collection rate to Inlet gas flow rate when added
with outlet dust concentration will give Inlet dust concentration.
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To calculate ash collection rate AMT density sampling is done. The outlet flow to MDT from
AMT was closed and the level in the tank is made to rise to 65% as displayed on DCS. WWL
and hot water inlet supply is then closed to maintain the volume constant during sampling
period. Density of AMT sample was taken at an interval of 15 minutes.
The solids fired in the boiler remained constant during the experiment. The soot blowing was
switched off to prevent ash from superheaters, boiler bank and economizer from falling into
the tank. The system is assumed to be in steady state with no excess ash falling and no ash
building on collection plate. Multiple samples are taken to determine average ash collection
rate as there is variability in ash falling rate depending upon rapper frequency. We assume
that all the ash falling is collected and is falling from ESP only during the experiment.
Constants during the experiment are time interval, tank level, MDT outlet flow = 0, Hot water
inlet flow = 0, WWL inlet flow = 0, firing rate, % solids in BL, soot blower = off. Variables
during the experiment are Gas flow rate and ESP ash quantity.
71 | P a g e
Gas flowrates and their temperatures are taken are taken from DCS. Collection efficiency is
calculated after processing these values in appropriate units.
Observation table and Results:
Tank Volume = 10 m3
Tank Level = 63.5 %
Thus, Volume of tank filled = 6.35 m3
ρ
(kg/m3) 0.75 0.8 1.2
Temp
(°C) 200 160 30
Pressure = 1 bar
Firing rate = 26 TPH
Solids firing rate = 17.5 TPH
Amount of water = 8.5 TPH
Vapor generation rate = 3.11
(m3/s)
Symbol A B
Sample Time
Temp. at
density
calculation
Twaddell Density ∆ρ ESP Ash
collected
Weight Volume Ρ (/15
min)
Unit Hours °C g ml kg/m3 kg/m3 kg
Formula A*6.35
1 1445 39 15 53.138 50 1062.76
2 1500 40 16 53.29 50 1065.8 3.04 19.304
3 1515 41 17 53.558 50 1071.16 5.36 34.036
4 1530 40 18 53.724 50 1074.48 3.32 21.082
5 1545 40 19 54.01 50 1080.2 5.72 36.322
72
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29
5
30
.63
54
03
43
Conclusion:
The collection efficiency is close to designed value of 99.53. But to meet environmental
norms outlet dust concentration, must be 75 mg/Nm3. Thus, required CE = 99.676.
When the amount of liquor burned is increased to 27 TPH or 28 TPH, it is believed that outlet
dust concentration increases significantly. Thus, it can be deduced that maximum capable
load of ESP is reached at firing rate of 26 TPH. It can be concluded that maximum collection
efficiency of ESP is 99.50, under these conditions. To get 75 mg/Nm3
outlet dust
concentration inlet dust concentration should be 15 g/Nm3.
Thus, either process conditions can be varied like moisture or dust composition or inlet dust
load can be reduced to reduce outlet dust concentration. A multi-cyclone or other mechanical
dust collector is used to reduce the inlet dust load.
Specific Collection Area calculation:
Total collection area = 3276.8 m2
Gas flow rate = 17.424 Nm3/s
Inlet temperature = 180 °C
Outlet temperature = 160 °C
Gas flow rate (@170 °C) = 26.344 m3/s
Thus, SCA = 124.38 m2/m3s-1
For 1000 m3/hr, CA = 34.55 m2
For 99.5 % above efficiencies conservative SCA is 20-25 m2 for 1000 m3/hr. The SCA in
operation is sufficiently above the ideal value.
A standard of outlet dust concentration equal to 75 mg/Nm3 in ESPs of both the units is targeted.
Experiment 9.1. Calculation of Practical Collection Efficiency
74 | P a g e
Figure 9.2. Dust collection systems
9.4. DUST COMPOSITION
To understand dust characteristics, dust composition is very important.
Quantity Unit Value As Base Group
Moisture % by weight 0.31
Loss on Ignition % by weight 24.8
Carbonates as Na2CO3 % by weight 28 15.85
Sulfates as Na2SO4 % by weight 27.9 18.86
Chlorides as NaCl % by weight 33.1 20.09
Acid insoluble % by weight 0.42
Water insoluble % by weight 0.19
Table 9.5. ESP dust composition
Elemental analysis of ESP is also done to determine the amount of Na and K in the ash.
Experiment: Elemental analysis of ESP ash to determine Na and K
Objective: To determine % of Na and K in ESP ash
Observation table and Results:
Sample Wt of sol.
(g)
PPM Wt in g % Wt
Na K Na K
1 10002 39.8 67.8 0.398 0.678 23.044 - Na
2 6251.88 76.3 108.8 0.477 0.68 35.765 – K
Conclusion:
Based on above data and various journals, articles and discussions, the final composition of
ESP ash is concluded to be:
75 | P a g e
Quantity Units Value
Na2SO4 mole 0.098
K2SO4 mole 0.098
NaCl mole 0.283
KCl mole 0.283
Na2CO3 mole 0.198
K2CO3 mole 0.066
The presence of K and Cl expressed as ratios:
Chloride Enrichment Factor (CEF),
Cl/(Na + K) mole % = 29.525
For wood based paper plants, the general CEF value is 1.5-2.5 %.
Potassium Enrichment Factor, (PEF),
K/(K + Na) mole % = 47.835
For wood based paper plants, the general PEF value is 1.2-2 %.
Experiment 9.2. ESP Dust elemental analysis
To increase the collection efficiency of ESP, treating K and Cl can help.
9.5. POTASSIUM & CHLORIDES PURGING
The chloride and potassium content in the ESP dust are very large. The presence of these elements
adversely affects ESP and Recovery Boiler. High content of Chlorides and Potassium causes
corrosion, cracking and fouling in Recovery boilers and causes ESP problems in form of inlet corona
suppression and build ups on the ESP internals.
Also, it is important to note that at low chloride concentrations, potassium has very little effect on
sticky deposit temperature. On the other hand, when the chloride mole % [Cl/(Na+K)] exceeds 10%,
potassium has a significant effect on lowering the sticky temperature.9
9 Moyer S., Wiggins D., Blair M.A. and Hiner L.A. (2000). Liquor Cycle Chloride Control Restores Recovery Boiler
Availability
Figure 9.3. Effect of Chloride and Potassium on Sticky Deposit Temperature (TSTK)
76 | P a g e
The sticky temperature is the temperature that results in a sticky deposit with 15% liquid phase
(TSTK).
Of the various sources of potassium and chlorides in the system the important ones are10:
a. Bound to wheat straw or wood
b. Makeup caustic
c. Make up lime
d. Fresh water
The 2 major points that can be interfered for reduction of potassium and chlorides are:
a. Wet washing
By adapting to rigorous wet washing and using hot water with minimum reuse of water, potassium
and chloride content can be reduced. Potassium and chlorides easily dissolve in water and can be
removed at the potential source.
b. Purging precipitator dust
The potassium and chlorine content is highest in precipitator dust. Thus purging precipitator dust
and treating it is one important method of potassium and chlorides removal.
Various methods for potassium and chlorides removal through precipitator dust purging are:
a. Ash Purging
By purging some amount of ESP ash highly concentrated with potassium and chlorides, a
proper balance can be maintained. It is practiced at Alabama River Pulp and Alabama Pine
Pulp of 1200 and 1600 TPD capacity. It has disadvantage that alkali is also lost with ash and
needs to be covered by makeup caustic.
b. Ash leaching
It is the most popular method where ash and water are mixed in a slurry. Most of the alkali
remains solid while most of the potassium and chlorine dissolve. By centrifuge liquid fraction
is separated from solid fraction, where liquid fraction is sent to waste water treatment and
alkali is returned to liquor cycle.
c. Electrodialysis using a bipolar membrane
d. Specific crystallization processes
Sodium sulfate and carbonate crystals are selectively removed from a concentrated filtrate
stream containing potassium and chlorine. It is used in Champion International
Corporation’s bleach filtrate recycle process in Canton, North Carolina.
Systems based on Ash Leaching:
a. AshLeach [Metso Power]
b. ARC [Andritz]
CEF in the range of 1.5 – 2.5 % and PEF in the range of 1.2 – 2 % are targeted.
10
Michael A., Craig J., A. Mark and Douglas W. An overview of various strategies for balancing saltcake,
chloride and potassium levels in an ECF kraft mill
77 | P a g e
9.6. ESP ORE LOSS
For Recovery 2
Outlet gas concentration = 120 mg/Nm3
Inlet dust concentration = 23.166 g/Nm3
Gas Flow Rate = 17.424 Nm3/s
Thus,
Outlet SPM flow rate = 2.091 g/s or 0.181 MT/day
With ESP shutdown,
Outlet SPM flow rate = 403.64 g/s
% Weight of Na as Na2O = 31.06
Thus,
Outlet Na flow rate = 0.0561 MT of Na as Na2O/day
Thus,
Outlet Na flow rate = 10.83 MT of Na as Na2O/day
Outlet Na flow rate (considering 2 hour ESP shut down) = 0.954 MT of Na as Na2O/day
For Recovery 1
Inlet dust concentration = 23 g/Nm3 (Considering similar performance as Recovery 2 boiler)
With 80% collection efficiency, outlet dust concentration = 4.6 g/Nm3
Gas flow rate = 5.5 Nm3/s
Thus, Outlet SPM flow rate = 25.3 g/s or 2.186 MT/day
Thus, Outlet Na flow rate = 0.6789 MT of Na as Na2O/day
Data table 9.6 in Appendix A
The soda loss in Recovery 2 through Flue gas carryover of total soda losses is 11.48 %.
The corresponding loss in ORE in Recovery 2 through Flue gas carryover is 0.817 %.
The soda loss in ORE in Recovery 1 through Flue gas carryover is 8.15 %.
The corresponding loss in ORE in Recovery 1 through Flue gas carryover is 0.580 %.
The combined soda loss in ORE in Recovery 1 and Recovery 2 through Flue gas carryover is 19.63 %.
The corresponding loss in ORE in Recovery 1 and Recovery 2 through Flue gas carryover is 1.397 %
A standard of 75 mg/Nm3 of outlet dust concentration is targeted for Recovery 1 and Recovery 2.
Also identified performance parameters must be in desired range.
78 | P a g e
10. ORE LOSS DATA
Mud Filter,
Grifts and
Stones
Flue gas
carryover [ESP]
Soda Carryover
with Pulp
Screen Losses
in Pulp mill Total
% Loss of Total
soda loss 7.50 19.63 69.59 2.81 99.53
% Loss in ORE 0.712 1.397 5.108 0.201 7.418
Table 10.2. % Loss from significant loss points
99.53 % of the total soda losses are explained by these 4 major loss points. Steps to reduce soda
losses from these points and set targets are discussed in the report before.
% Loss (ORE)
Recovery I & II SFL and WFL
Date Mud
Filter
Grifts
and
Stones
Dregs
Washer
Flue gas
carryov
er [ESP]
Condenser,
Vibro
Screen, &
MDT
Outlet
Seepage
&
Overflow
Soda
Carryover
with Pulp
Screen
Losses
in Pulp
mill
Seepage
&
Overflow
01-Jun -
17-Jun 0.677 0.035 0 1.397 0.05 0 5.108 0.201 0
Table 10.3. % Net Loss in ORE from individual loss points
ORE based on individual losses is 92.532 %.
Data table 10.1 in Appendix A
The average ORE based on stock (June 1st – June 17th 2010) is 94.000 %.
If the suggestions are implemented and standards are met, ORE can be increased to 97-97.5 %.
While the ORE from stock has come out to be 94 %, in general the ORE on average basis is
approximately 94.5 %. However ORE based on individual losses has come significantly higher than
that based on stock. The reason of difference in ORE based on stock and ORE based on individual
losses could be:
a. Screen losses are calculated based on limited number of sampling and could be lower than
estimated.
b. Due to very high soda carryover through pulp in WFL, ORE could have been affected.
79 | P a g e
11. FUTURE WORK
a. A rigorous study can be done by quantifying loss data from every possible major soda loss
source.
b. WBL sampling should be done for few weeks and results should be analyzed.
c. Quotations for online analyzers can be invited from suppliers and the economic viability of
the change can be analyzed.
d. Samples should be analyzed while displacement washing for weeks and results should be
tabulated to see any benefits.
e. Mud cake sampling can be done with Filter Aids and benefits can be noted.
f. Causticizing control models can be studied for better lime control.
g. Proper steps should be taken to reduce soda loss in pulp carryover.
h. % Charging (White liquor charged per tonne of fibres cooked in the digester) could be
plotted against the soda carryover as kg/MT and production. A relative study can be done
whether higher production has resulted in increased charging and thus, increased soda loss.
i. Pulp mill reject should be treated with hot water and moisture should be reduced. Samples
should be analyzed to observe any benefits.
j. ESP process parameters like resistivity and theoretical collection efficiency should be
evaluated through an external lab for better understanding of performance limitations.
k. The amount of Potassium and Chlorine needs to be reduced through proper steps.
In brief,
First, Check Technical and Economic viability for
a. Composite sampling or Automation in WBL testing
b. Automation in lime slaking
c. Filter Aid use in Mud filter
d. Pulp mill reject washing
e. Potassium and Chlorides purging
With the proposed benefits if technical and economical viability is found then,
Perform rigorous sampling for a month to validate observations in
a. WBL TTA
b. Mud cake displacement washing
c. ESP collection efficiency
d. ESP Dust composition
80 | P a g e
12. REFERENCES
Dalmon J. (1980). Electrostatic precipitators for large power station boile,
Dalmon J. and Tidy D. (1972). A comparison of chemical additives as aids to the electrostatic
precipitation of fly ash
Johnson M. (1996). The effect of humidity on the performance of electrostatic precipitators at
Tarong Power Station
Harker J.R. and Pimkarkar P.M. (1988). The effect of additives on the electrostatic precipitation
of flu ash
Tran H.N. Kraft Recovery Boiler Plugging and Prevention
Jaye P. H. History of Alabama River Pulp Company and The Claiborne Mill Complex
Unified Air Toxics, (August 2000). www.epa.gov/ttn/uatw/pulp/pulppg.html
Moyer S., Wiggins D., Blair M.A. and Hiner L.A. (2000). Liquor Cycle Chloride Control Restores
Recovery Boiler Availability
Mckean W. and Jacobs R. S. (1997). Wheat Straw as a Paper Fiber Source
M. Brongers, A. J. Mierzwa. Pulp and Paper
American Forest & Paper Association (AF&PA). (October 1999). www.afandpa.com
Michael A., Craig J., A. Mark and Douglas W. An overview of various strategies for balancing saltcake,
chloride and potassium levels in an ECF kraft mill
Uschan R.M. and Trick L.C. (Sept. 1994). Corrosion Control Needs of the Pulp and Paper Industry
Rose, H. E., and A. J. Wood. An Introduction to Electrostatic Precipitation in Theory and Practice
U.S. EPA 1985
Pirita Mikkanen. Fly ash particle formation in Kraft Boilers
Hein A.G and Gibson D. Skewed Gas Flow Technology Improves Precipitator Performance
Prakash H. Dhargalkar, Jose Astolphi, Jr. Advancements in air pollution control for pulp and paper
Industry
Ibach, S. Conversion to high solids firing
Kraft Recovery Boilers, TAPPI Press
ESP Design Parameters and Their Effects on Collection Efficiency, Lesson 3
Gallaer C. A. (1983). Electrostatic Precipitator Reference Manual. Electric Power Research Institute
Coal and Ash Testing and Predictive Analyses, Neundorfer, Inc.
Chandra A., Sanjeev Kumar, Subodh Kumar and Sharma P.K. Investigations on Fly Ash Resistivity:
Development of Empirical Relations Based on Experimental Measurement
Thomas e. Sulpizio. Advances in filter aid and precoat Filtration technology. Presentation at the
American filtration & separations society
Rees, R. H. and Cain, C. W. (1990). Let Diatomite Enhance Your Filtration
Environmental, Health, and Safety Guidelines Pulp and Paper Mills
Arpalahti.O., White liquor preparation, Paper Making Science and Technology
81 | P a g e
LIST OF EXPERIMENTS
Experiment 4.1. FMEA on identified exit points of soda for permanent losses [Page 27]
Experiment 5.1. Frequent sampling of WBL from SFL and WFL [Page 32]
Experiment 6.1. Mud cake sampling from Mud filter of Recovery 2 [Page 42]
Experiment 6.2. Vat and Mud sampling to test homogeneity from Mud filter of Recovery 2 [Page 43]
Experiment 6.3. Displacement washing in mud filter of Recovery 2 [Page 46]
Experiment 7.1. Analysis of total washable alkali in washed pulp in WFL [Page 55]
Experiment 8.1. Reject stream analysis for TTA in WFL and SFL [Page 56]
Experiment 8.2. Analysis of total washable alkali in pulp from reject stream in WFL and SFL [Page 57]
Experiment 9.1. Calculation of Practical Collection Efficiency [Page 70]
Experiment 9.2. ESP Dust elemental analysis [Page 74]
LIST OF TABLES
Table 5.1. PME, SRE and ORE over Time [Page 31]
Table 6.1. Loss through Mud filter for Recovery 1 and 2 [Page 84]
Table 6.2. Loss through Mud filter for Recovery 1 and 2 combined [Page 85]
Table 6.3. Loss through Grifts and stones for Recovery 1 and 2 [Page 86]
Table 6.4. Combined loss through Mud filter and Grifts and stones for Recovery 1 and 2 [Page 87]
Table 7.1. Soda carryover with pulp in SFL [Page 88]
Table 7.2. Soda carryover with pulp in WFL [Page 90]
Table 7.3. Combined soda carryover with pulp in SFL and WFL [Page 92]
Table 7.4. WFL production and total soda loss [Page 94]
Table 7.5. SFL production and total soda loss [Page 98]
Table 8.1. Soda loss from Screens as Reject in WFL and SFL [Page 101]
Table 8.2. Combined soda loss from Screens as Reject in WFL and SFL [Page 104]
Table 9.1. BHEL ESP Design Conditions [Page 64]
Table 9.2. ESP characteristics with Resistivity [Page 67]
Table 9.3. Corona power of ESP of Recovery 1 [Page 69]
Table 9.4. Corona power of ESP of Recovery 2 [Page 69]
Table 9.5. ESP dust composition [Page 75]
Table 9.6. ESP ORE Loss [Page 106]
Table 10.1. Average ORE based on stock [Page 108]
Table 10.2. % Loss from significant loss points [Page 31]
Table 10.3. %Loss in ORE from individual loss points [Page 31]
82 | P a g e
LIST OF FIGURES
Figure 1. Sulfuric Acid Plant (SAP) at Abhishek Industries, Dhaula complex [Page 9]
Figure 2. COGEN-1, a 20 MW unit at Abhishek Industries, Dhaula complex [Page 9]
Figure 3. Demineralised water plant at Abhishek Industries at Dhaula complex [Page 10]
Figure 1.1. Paper making process [Page 11]
Figure 1.2. Paper making flowchart [Page 12]
Figure 1.3. Chemical Recovery Cycle [Page 13]
Figure 1.4. Multiple effect evaporators [Page 13]
Figure 1.5. Recovery Boiler Process flow [Page 14]
Figure 1.6. Recovery Boiler [Page 14]
Figure 1.7. Recausticizing Process flow [Page 15]
Figure 4.1. Process Flow Diagram of Recovery 2 [Page 18]
Figure 4.2. Evaporator Process Flow Diagram [Page 19]
Figure 4.3. 7 effect/11 body Evap. at Recovery2 at Abhishek Industries, Dhaula complex [Page 19]
Figure 4.4. Condensers at Recovery 2 at Abhishek Industries, Dhaula complex [Page 20]
Figure 4.5. Recovery Boiler Process Flow Diagram [Page 20]
Figure 4.6. Rotary lime kiln [Page 21]
Figure 4.7. Recausticizing Process Flow Diagram [Page 23]
Figure 4.8. Wet Washing in SFL [Page 24]
Figure 4.9. Digester in SFL [Page 24]
Figure 4.10. Pulp washing in SFL [Page 25]
Figure 4.11. Digester Feed Belt in SFL at Abhishek Industries, Dhuala complex [Page 26]
Figure 5.1. PME versus Time plot [Page 31]
Figure 5.2. SRE versus Time plot [Page 31]
Figure 5.3. ORE versus Time plot [Page 31]
Figure 5.4. Proposed collection tank design for WBL composite sampling [Page 37]
Figure 6.1. Lime mud filter flowsheet [Page 39]
Figure 6.2. Vacuum disk filter sketch [Page 39]
Figure 6.3. Vacuum disk filter in operation [Page 39]
Figure 7.1. Production versus Time in WFL [Page 50]
Figure 7.2. Soda carryover as kg/MT of unbleached pulp versus Time in WFL [Page 50]
Figure 7.3. Production and Soda carryover versus Time in WFL [Page 51]
Figure 7.4. Soda carryover versus Production in WFL [Page 51]
Figure 7.5. Production versus Time in SFL [Page 52]
83 | P a g e
Figure 7.6. Soda carryover as kg/MT of unbleached pulp versus Time in SFL [Page 52]
Figure 7.6. Production and Soda carryover versus Time in SFL [Page 53]
Figure 7.8. Soda carryover versus Production in SFL [Page 53]
Figure 7.9. Brown Stock Washer [Page 54]
Figure 8.1. HD Cleaner, Delta Knotter and Vibratory Screen in SFL [Page 59]
Figure 8.2. HD cleaner [Page 60]
Figure 8.3. Delta Knotter [Page 60]
Figure 8.4. Vibratory Screen [Page 60]
Figure 8.5. Delta Screen, Opti Screen, Centricleaner and Vibratory Screen in SFL [Page 60]
Figure 8.6. Vibratory Screen in WFL [Page 61]
Figure 8.7. Centricleaner [Page 61]
Figure 8.8. Delta Screen [Page 61]
Figure 8.9. Pressure Screen [Page 61]
Figure 8.10. Pressure Screen, Centricleaner and Vibratory Screen in WFL [Page 61]
Figure 8.11. Hot water header for washing [Page 62]
Figure 9.1. ESP [Page 63]
Figure 9.2. Dust collection systems [Page 74]
Figure 9.3. Effect of Chloride and Potassium on Sticky Deposit Temperature (TSTK) [Page 75]
AP
PE
ND
IX A
Ta
ble
6.1
. Lo
ss t
hro
ug
h M
ud
fil
ter
for
Re
cove
ry 1
an
d 2
Loss
th
rou
gh
Mu
d F
ilte
r
Re
cove
ry I
Re
cove
ry I
I
Da
te
Sh
ift
To
tal
Loss
(MT
)
WL
Co
nsu
me
d
(TT
A N
a2O
MT
)
Lim
e
con
sum
pti
on
(MT
)
%
Ca
(OH
) 2
in M
ud
Ca
ke
Ca
CO
3
Pro
du
cti
on
(M
T)
% S
od
a
(TT
A
Na
2O
)
To
tal
So
da
lo
ss
(Na
2O
MT
)
Lim
e
con
sum
pti
on
(MT
)
%
Ca
(OH
) 2
in M
ud
Ca
ke
Ca
CO
3
Pro
du
ctio
n
(MT
)
% S
od
a
(TT
A
Na
2O
)
To
tal
So
da
lo
ss
(Na
2O
MT
)
01
-Ju
n
C
1.4
89
46
.83
20
5
11
2
.1
19
.10
00
5
0.4
4
0.0
84
04
02
2
8
1.4
4
9.0
70
32
0
.48
0
.23
55
37
5
01
-Ju
n
A
48
.43
45
1
1
2
19
.12
52
2
0.4
5
0.0
86
06
35
2
6
1.5
4
5.5
04
86
0
.46
0
.20
93
22
3
01
-Ju
n
B
37
.62
21
1
1
2
19
.12
52
2
0.4
5
0.0
86
06
35
2
6
1.5
4
5.5
04
86
0
.45
0
.20
47
71
9
02
-Ju
n
C
13
.64
1
44
.39
64
3
11
.5
1.9
2
0.0
20
93
0
.45
0
.09
00
94
2
27
1
.4
47
.31
78
1
0.4
6
0.2
17
66
19
02
-Ju
n
A
46
.40
72
9
2
1
5.6
47
91
0
.5
0.0
78
23
95
2
7
1.5
4
7.2
55
04
0
.45
0
.21
26
47
7
02
-Ju
n
B
38
.41
44
1
1
2
19
.12
52
2
0.4
6
0.0
87
97
6
27
1
.5
47
.25
50
4
0.4
4
0.2
07
92
22
03
-Ju
n
C
10
.12
3
35
.28
46
7
10
1
.9
17
.40
95
0
.45
0
.07
83
42
8
29
1
.5
50
.75
54
2
0.4
5
0.2
28
39
94
03
-Ju
n
A
38
.22
76
2
11
1
.7
19
.20
11
2
0.4
5
0.0
86
40
5
23
1
.3
40
.36
13
6
0.4
4
0.1
77
59
03
-Ju
n
B
42
.49
79
4
11
1
.8
19
.17
57
5
0.4
5
0.0
86
29
09
2
3
1.3
4
0.3
61
36
0
.46
0
.18
56
62
3
04
-Ju
n
C
4.3
94
39
.73
04
4
11
1
.9
19
.15
04
5
0.4
5
0.0
86
17
7
31
1
.4
54
.32
78
5
0.4
6
0.2
49
90
81
04
-Ju
n
A
30
.30
21
6
10
0
1
7.8
57
14
0
0
2
2
1.5
3
8.5
04
11
0
.44
0
.16
94
18
1
04
-Ju
n
B
27
.88
12
1
1
1.8
1
9.1
75
75
0
.43
0
.08
24
55
7
22
1
.2
38
.65
79
3
0.4
3
0.1
66
22
91
05
-Ju
n
C
17
.85
6
40
.97
62
8
10
1
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17
.40
95
0
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0
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66
01
8
23
1
.3
40
.36
13
6
0.4
4
0.1
77
59
05
-Ju
n
A
40
.44
38
6
11
2
1
9.1
25
22
0
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0
.08
79
76
1
5
1.5
2
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52
8
0.4
5
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18
13
76
05
-Ju
n
B
41
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21
2
11
2
1
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25
22
0
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0
.08
79
76
4
1
.3
7.0
19
36
8
0.4
5
0.0
31
58
72
06
-Ju
n
C
22
.41
9
44
.54
12
6
11
1
.9
19
.15
04
5
0.4
5
0.0
86
17
7
29
1
.4
50
.82
28
3
0.4
4
0.2
23
62
04
06
-Ju
n
A
41
.74
74
7
11
1
.9
19
.15
04
5
0.4
6
0.0
88
09
21
2
8
1.4
4
9.0
70
32
0
.45
0
.22
08
16
4
06
-Ju
n
B
49
.50
07
8
12
1
.9
20
.89
14
0
.45
0
.09
40
11
3
30
1
.4
52
.57
53
4
0.4
6
0.2
41
84
66
07
-Ju
n
C
22
.62
5
45
.65
22
8
11
1
.8
19
.17
57
5
0.4
4
0.0
84
37
33
2
9
1.5
5
0.7
55
42
0
.46
0
.23
34
74
9
07
-Ju
n
A
40
.76
67
2
10
1
.9
17
.40
95
0
.45
0
.07
83
42
8
25
1
.5
43
.75
46
7
0.4
5
0.1
96
89
6
07
-Ju
n
B
41
.49
19
4
11
1
.9
19
.15
04
5
0.4
5
0.0
86
17
7
24
1
.5
42
.00
44
8
0.4
5
0.1
89
02
02
85
| P
ag
e
Ta
ble
6.2
. Lo
ss t
hro
ug
h M
ud
fil
ter
for
Re
cove
ry 1
an
d 2
co
mb
ine
d
Loss
th
rou
gh
Mu
d F
ilte
r
Co
mb
ine
d
Da
te
Sh
ift
To
tal
Loss
(MT
)
WL
Co
nsu
me
d
(TT
A N
a2O
MT
)
To
tal
So
da
lo
ss
(Na
2O
MT
)
% L
oss
th
rou
gh
Mu
d f
ilte
r o
f
To
tal
loss
Ge
ne
ral
Loss
%
(%)
% L
oss
(OR
E)
Av
g %
Loss
(OR
E)
01
-Ju
n
C
1.4
89
46
.83
20
5
0.9
05
79
9
60
.83
27
03
34
7.2
32
0.6
82
39
1
0.6
77
01
-Ju
n
A
48
.43
45
0
.60
98
67
01
-Ju
n
B
37
.62
21
0
.77
30
44
02
-Ju
n
C
13
.64
1
44
.39
64
3
0.8
94
54
15
6
.55
77
41
65
3
0.6
93
2
02
-Ju
n
A
46
.40
72
0
.62
68
15
02
-Ju
n
B
38
.41
44
0
.77
02
79
03
-Ju
n
C
10
.12
3
35
.28
46
7
0.8
42
69
04
8
.32
45
12
12
7
0.8
69
33
5
03
-Ju
n
A
38
.22
76
2
0.6
90
58
7
03
-Ju
n
B
42
.49
79
4
0.6
39
92
1
04
-Ju
n
C
4.3
94
39
.73
04
4
0.7
54
18
81
1
7.1
64
04
40
2
0.8
45
91
3
04
-Ju
n
A
30
.30
21
6
0.5
59
09
6
04
-Ju
n
B
27
.88
12
0
.89
19
45
05
-Ju
n
C
17
.85
6
40
.97
62
8
0.5
79
86
86
3
.24
74
72
10
3
0.6
20
33
9
05
-Ju
n
A
40
.44
38
6
0.5
09
62
9
05
-Ju
n
B
41
.22
21
2
0.2
90
04
6
06
-Ju
n
C
22
.41
9
44
.54
12
6
0.9
54
56
39
4
.25
78
34
31
4
0.6
95
52
9
06
-Ju
n
A
41
.74
74
7
0.7
39
94
5
06
-Ju
n
B
49
.50
07
8
0.6
78
49
07
-Ju
n
C
22
.62
5
45
.65
22
8
0.8
68
28
42
3
.83
77
20
43
4
0.6
96
23
7
07
-Ju
n
A
40
.76
67
2
0.6
75
15
6
07
-Ju
n
B
41
.49
19
4
0.6
63
25
5
86
| P
ag
e
Ta
ble
6.3
. Lo
ss t
hro
ug
h G
rift
s a
nd
sto
ne
s fo
r R
eco
ve
ry 1
an
d 2
Gri
fts
an
d S
ton
es
Re
cove
ry I
Re
cove
ry I
I C
om
bin
ed
Da
te
Sh
ift
To
tal
Loss
(MT
)
WL
Co
nsu
me
d
(TT
A N
a2
O
MT
)
To
tal
Loss
(MT
Ca
CO
3)
% S
od
a
(TT
A
Na
2O
)
To
tal
So
da
loss
(Na
2O
)
To
tal
Loss
(MT
Ca
CO
3)
% S
od
a
(TT
A
Na
2O
)
To
tal
So
da
loss
(Na
2O
)
To
tal
So
da
loss
(Na
2O
)
Ge
ne
ral
Loss
%
(%)
% L
oss
(OR
E)
Av
g %
Loss
(OR
E)
01
-Ju
n
C
1.4
89
46
.83
20
5
2.5
0
.5
0.0
12
5
6
0.5
0
.03
0
.04
25
0.2
69
0.0
32
0.0
35
01
-Ju
n
A
48
.43
45
01
-Ju
n
B
37
.62
21
02
-Ju
n
C
13
.64
1
44
.39
64
3
2.5
0
.5
0.0
12
5
6
0.5
0
.03
0
.04
25
0
.03
3
02
-Ju
n
A
46
.40
72
02
-Ju
n
B
38
.41
44
03
-Ju
n
C
10
.12
3
35
.28
46
7
2.5
0
.5
0.0
12
5
6
0.5
0
.03
0
.04
25
0
.03
7
03
-Ju
n
A
38
.22
76
2
03
-Ju
n
B
42
.49
79
4
04
-Ju
n
C
4.3
94
39
.73
04
4
2.5
0
.5
0.0
12
5
6
0.5
0
.03
0
.04
25
0
.04
3
04
-Ju
n
A
30
.30
21
6
04
-Ju
n
B
27
.88
12
05
-Ju
n
C
17
.85
6
40
.97
62
8
2.5
0
.5
0.0
12
5
6
0.5
0
.03
0
.04
25
0
.03
5
05
-Ju
n
A
40
.44
38
6
05
-Ju
n
B
41
.22
21
2
06
-Ju
n
C
22
.41
9
44
.54
12
6
2.5
0
.5
0.0
12
5
6
0.5
0
.03
0
.04
25
0
.03
1
06
-Ju
n
A
41
.74
74
7
06
-Ju
n
B
49
.50
07
8
07
-Ju
n
C
22
.62
5
45
.65
22
8
2.5
0
.5
0.0
12
5
6
0.5
0
.03
0
.04
25
0
.03
3
07
-Ju
n
A
40
.76
67
2
07
-Ju
n
B
41
.49
19
4
87
| P
ag
e
Ta
ble
6.4
. C
om
bin
ed
loss
th
rou
gh
Mu
d f
ilte
r a
nd
Gri
fts
an
d s
ton
es
for
Re
cove
ry 1
an
d 2
Mu
d F
ilte
r a
nd
Gri
fts
Co
mb
ine
d
Da
te
Sh
ift
To
tal
Loss
(MT
)
WL
Co
nsu
me
d
(TT
A N
a2
O
MT
)
Ge
ne
ral
Loss
% (
%)
Av
g %
Loss
(OR
E)
01
-Ju
n
C
1.4
89
46
.83
20
5
7.5
01
0
.71
2
01
-Ju
n
A
48
.43
45
01
-Ju
n
B
37
.62
21
02
-Ju
n
C
13
.64
1
44
.39
64
3
02
-Ju
n
A
46
.40
72
02
-Ju
n
B
38
.41
44
03
-Ju
n
C
10
.12
3
35
.28
46
7
03
-Ju
n
A
38
.22
76
2
03
-Ju
n
B
42
.49
79
4
04
-Ju
n
C
4.3
94
39
.73
04
4
04
-Ju
n
A
30
.30
21
6
04
-Ju
n
B
27
.88
12
05
-Ju
n
C
17
.85
6
40
.97
62
8
05
-Ju
n
A
40
.44
38
6
05
-Ju
n
B
41
.22
21
2
06
-Ju
n
C
22
.41
9
44
.54
12
6
06
-Ju
n
A
41
.74
74
7
06
-Ju
n
B
49
.50
07
8
07
-Ju
n
C
22
.62
5
45
.65
22
8
07
-Ju
n
A
40
.76
67
2
07
-Ju
n
B
41
.49
19
4
88
| P
ag
e
S
od
a C
arr
yo
ve
r
S
FL
Da
te
Sh
ift
To
tal
Loss
(MT
)
% S
od
a
(TT
A N
a2
O,
Kg
/MT
)
Pu
lp
Pro
du
ctio
n
(MT
)
So
da
Loss
(MT
)
To
tal
So
da
Loss
(MT
)
% L
oss
in
So
da
Ca
rry
ov
er
%
Ge
ne
ral
Loss
(To
tal
Loss
)
WL
Co
nsu
me
d
(TT
A
Na
2O
MT
)
% L
oss
(SF
L P
ME
)
Av
g %
Loss
(S
FL
PM
E)
RE
SU
LT
3
6.7
5
4.9
75
01
-Ju
n
C
1.4
89
14
.53
94
36
6
86
1
.25
03
92
3.7
66
08
1
25
2.9
26
85
36
.75
24
.98
70
5
5.0
04
15
84
4.9
75
01
-Ju
n
A
13
.92
81
69
8
8.8
8
1.2
37
93
6
26
.15
45
4
.73
31
65
1
01
-Ju
n
B
15
.10
70
42
3
84
.58
1
.27
77
54
2
1.1
95
1
6.0
28
53
32
02
-Ju
n
C
13
.64
1
14
.36
47
88
7
81
.9
1.1
76
47
6
3.5
54
53
7
26
.05
77
47
27
.47
34
3
4.2
82
23
27
02
-Ju
n
A
15
.06
33
80
3
83
.51
1
.25
79
43
2
4.6
94
2
5.0
94
08
24
02
-Ju
n
B
12
.92
39
43
7
86
.67
1
.12
01
18
2
2.0
27
4
5.0
85
11
31
03
-Ju
n
C
10
.12
3
12
.4
74
.47
0
.92
34
28
2.8
93
57
5
28
.58
41
64
18
.66
86
7
4.9
46
40
49
03
-Ju
n
A
11
.48
30
98
6
80
.47
0
.92
40
45
2
1.3
23
62
4
.33
34
33
7
03
-Ju
n
B
11
.83
23
94
4
88
.41
1
.04
61
02
2
5.7
83
94
4
.05
71
84
4
04
-Ju
n
C
4.3
94
12
.79
29
57
7
84
.07
1
.07
55
04
2.5
00
15
9
56
.89
93
89
22
.63
64
4
4.7
51
20
63
04
-Ju
n
A
11
.87
60
56
3
53
.11
0
.63
07
37
1
3.4
11
16
4
.70
30
78
3
04
-Ju
n
B
12
.92
39
43
7
61
.43
0
.79
39
18
1
6.7
26
2
4.7
46
55
25
05
-Ju
n
C
17
.85
6
13
.01
12
67
6
87
.88
1
.14
34
3
3.5
35
51
6
19
.80
01
56
24
.22
72
8
4.7
19
59
79
05
-Ju
n
A
12
.83
66
19
7
89
.12
1
.14
4
23
.63
28
6
4.8
40
71
56
05
-Ju
n
B
14
.49
57
74
6
86
.1
1.2
48
08
6
24
.60
91
2
5.0
71
64
09
06
-Ju
n
C
22
.41
9
14
.88
87
32
4
86
.67
1
.29
04
06
3.7
22
96
2
16
.60
62
82
28
.35
82
6
4.5
50
37
24
06
-Ju
n
A
13
.27
32
39
4
86
.99
1
.15
46
39
2
4.5
50
47
4
.70
31
24
2
06
-Ju
n
B
14
.58
30
98
6
87
.63
1
.27
79
17
2
7.3
52
78
4
.67
19
81
9
07
-Ju
n
C
22
.62
5
12
.74
92
95
8
85
.69
1
.09
24
87
3.4
62
85
1
5.3
05
41
5
23
.20
92
8
4.7
07
11
35
07
-Ju
n
A
13
.70
98
59
2
90
.27
1
.23
75
89
2
4.2
11
72
5
.11
15
28
6
07
-Ju
n
B
14
.27
74
64
8
79
.34
1
.13
27
74
2
4.6
29
94
4
.59
91
75
1
Ta
ble
7.1
. So
da
ca
rryo
ver
wit
h p
ulp
in S
FL
89
| P
ag
e
08
-Ju
n
C
2.4
68
14
.53
94
36
6
72
.83
1
.05
89
07
3.0
78
79
2
12
4.7
48
46
19
.58
1
5.4
07
82
99
08
-Ju
n
A
12
.92
39
43
7
78
.92
1
.01
99
58
2
0.1
57
45
5
.05
99
53
7
08
-Ju
n
B
12
.74
92
95
8
78
.43
0
.99
99
27
2
3.1
92
16
4
.31
14
88
3
09
-Ju
n
C
-6.8
34
14
.36
47
88
7
80
.92
1
.16
23
99
3.5
94
01
9
-52
.59
02
7
24
.95
65
4
.65
76
99
2
09
-Ju
n
A
14
.71
40
84
5
83
.67
1
.23
11
27
2
1.4
46
08
5
.74
05
71
09
-Ju
n
B
13
.44
78
87
3
89
.27
1
.20
04
93
2
4.2
89
79
4
.94
23
76
6
10
-Ju
n
C
-9.6
61
12
.48
73
23
9
86
.2
1.0
76
40
7
3.1
85
91
-3
2.9
77
02
23
.60
83
2
4.5
59
44
06
10
-Ju
n
A
12
.83
66
19
7
83
.6
1.0
73
14
1
26
.16
10
4
4.1
02
05
94
10
-Ju
n
B
14
.45
21
12
7
71
.71
1
.03
63
61
1
6.7
44
19
6
.18
93
76
7
11
-Ju
n
C
1.1
08
11
.70
14
08
5
71
.33
0
.83
46
61
1.6
35
41
9
14
7.6
01
03
22
.67
49
6
3.6
80
98
32
11
-Ju
n
A
14
.58
30
98
6
54
.91
0
.80
07
58
3
.83
4
20
.88
57
05
11
-Ju
n
B
0
0
0
0
0
12
-Ju
n
C
3.3
8
12
.13
80
28
2
20
.14
0
.24
44
6
2.4
65
11
1
72
.93
22
86
12
.61
41
6
1.9
37
97
99
12
-Ju
n
A
13
.44
78
87
3
80
.18
1
.07
82
52
2
3.4
65
52
4
.59
50
46
7
12
-Ju
n
B
15
.01
97
18
3
76
.06
1
.14
24
2
2.0
56
3
5.1
79
47
15
13
-Ju
n
C
16
.98
15
.45
63
38
9
0.5
1
1.3
98
95
3
3.1
48
55
6
18
.54
27
35
23
.26
86
6
.01
21
93
1
13
-Ju
n
A
12
.88
02
81
7
79
.84
1
.02
83
62
1
9.4
31
72
5
.29
21
80
5
13
-Ju
n
B
12
.13
80
28
2
59
.42
0
.72
12
42
1
9.5
24
12
3
.69
41
05
7
14
-Ju
n
C
-2.0
8
13
.18
59
15
5
81
.11
1
.06
95
1
2.9
17
10
3
-14
0.2
45
4
19
.67
25
6
5.4
36
55
53
14
-Ju
n
A
13
.18
59
15
5
55
.84
0
.73
63
02
1
9.1
51
82
3
.84
45
51
2
14
-Ju
n
B
13
.01
12
67
6
85
.41
1
.11
12
92
2
4.8
80
68
4
.46
64
87
1
15
-Ju
n
C
6.9
3
12
.57
46
47
9
90
.58
1
.13
90
12
3.3
02
85
2
47
.66
01
99
25
.84
47
4
.40
71
38
15
-Ju
n
A
12
.31
26
76
1
89
.33
1
.09
98
91
2
6.9
91
69
4
.07
49
25
8
15
-Ju
n
B
12
.18
16
90
1
87
.34
1
.06
39
49
2
1.5
01
6
4.9
48
23
09
16
-Ju
n
C
11
.62
13
.97
18
31
8
9.1
3
1.2
45
30
9
3.3
63
75
1
28
.94
79
4
23
.28
48
5
.34
81
64
16
-Ju
n
A
12
.74
92
95
8
88
.88
1
.13
31
57
2
4.9
87
96
4
.53
48
13
6
16
-Ju
n
B
11
.91
97
18
3
82
.66
0
.98
52
84
2
3.3
70
9
4.2
15
85
78
17
-Ju
n
C
5.1
7
15
.10
70
42
3
96
.57
1
.45
88
87
3.7
70
25
9
72
.92
57
12
26
.84
22
5
.43
50
50
3
17
-Ju
n
A
12
.83
66
19
7
94
.53
1
.21
34
46
2
5.4
36
88
4
.77
04
18
6
17
-Ju
n
B
11
.65
77
46
5
94
.18
1
.09
79
27
2
0.9
21
22
5
.24
79
08
9
90
| P
ag
e
S
od
a C
arr
yo
ve
r
W
FL
Da
te
Sh
ift
To
tal
Loss
(MT
)
% S
od
a
(TT
A N
a2
O,
Kg
/MT
)
Pu
lp
Pro
du
ctio
n
(MT
)
So
da
Loss
(MT
)
To
tal
So
da
Loss
(MT
)
% L
oss
in
So
da
Ca
rry
ov
er
%
Ge
ne
ral
Loss
(To
tal
Loss
)
WL
Co
nsu
me
d
(TT
A
Na
2O
MT
)
% L
oss
(SF
L P
ME
)
Av
g %
Loss
(S
FL
PM
E)
RE
SU
LT
3
2.8
4
5.4
27
01
-Ju
n
C
1.4
89
23
.92
67
60
6
49
.26
7
1.1
78
8
3.2
98
06
4
22
1.4
95
21
32
.84
21
.84
5
5.3
96
19
92
5.4
27
01
-Ju
n
A
24
.49
43
66
2
51
.17
9
1.2
53
59
7
22
.28
5
.62
65
58
2
01
-Ju
n
B
23
.88
30
98
6
36
.24
6
0.8
65
66
7
16
.42
7
5.2
69
78
02
02
-Ju
n
C
13
.64
1
21
.78
73
23
9
32
.69
8
0.7
12
40
2
2.8
92
85
6
21
.20
70
67
16
.92
3
4.2
09
66
68
02
-Ju
n
A
23
.40
28
16
9
52
.18
7
1.2
21
32
3
21
.71
3
5.6
24
84
6
02
-Ju
n
B
24
.66
90
14
1
38
.88
0
.95
91
31
1
6.3
87
5
.85
30
01
03
-Ju
n
C
10
.12
3
22
.44
22
53
5
40
.08
1
0.8
99
50
8
2.4
75
64
1
24
.45
56
08
16
.61
6
5.4
13
50
48
03
-Ju
n
A
23
.05
35
21
1
34
.20
7
0.7
88
59
2
16
.90
4
4.6
65
11
95
03
-Ju
n
B
22
.70
42
25
4
34
.68
7
0.7
87
54
1
16
.71
4
4.7
11
86
71
04
-Ju
n
C
4.3
94
25
.89
15
49
3
38
.20
3
0.9
89
13
5
2.4
86
50
6
56
.58
86
75
17
.09
4
5.7
86
44
47
04
-Ju
n
A
23
.05
35
21
1
40
.12
4
0.9
24
99
9
16
.89
1
5.4
76
28
61
04
-Ju
n
B
23
.31
54
93
2
4.5
49
0
.57
23
72
1
1.1
55
5
.13
10
80
6
05
-Ju
n
C
17
.85
6
22
.00
56
33
8
36
.53
3
0.8
03
93
2
2.8
72
25
2
16
.08
56
41
16
.74
9
4.7
99
87
95
05
-Ju
n
A
23
.88
30
98
6
49
.34
1
1.1
78
41
6
16
.81
1
7.0
09
79
1
05
-Ju
n
B
23
.14
08
45
1
38
.45
6
0.8
89
90
4
16
.61
3
5.3
56
67
45
06
-Ju
n
C
22
.41
9
24
.58
16
90
1
36
.86
2
0.9
06
13
2.9
77
92
5
13
.28
30
41
16
.18
3
5.5
99
27
25
06
-Ju
n
A
23
.62
11
26
8
37
.18
7
0.8
78
39
9
17
.19
7
5.1
07
86
09
06
-Ju
n
B
23
.35
91
54
9
51
.08
9
1.1
93
39
6
22
.14
8
5.3
88
27
82
07
-Ju
n
C
22
.62
5
26
.28
45
07
3
9.5
59
1
.03
97
89
3.2
07
57
8
14
.17
71
42
22
.44
3
4.6
33
02
06
07
-Ju
n
A
24
.49
43
66
2
38
.91
0
.95
30
76
1
6.5
55
5
.75
70
26
8
07
-Ju
n
B
23
.92
67
60
6
50
.76
8
1.2
14
71
4
16
.86
2
7.2
03
85
35
08
-Ju
n
C
2.4
68
2
2.8
78
87
32
2
2.0
59
0
.50
46
85
2
.46
33
71
9
9.8
12
43
3
11
.35
4
4.4
44
99
79
Ta
ble
7.2
. So
da
ca
rryo
ver
wit
h p
ulp
in W
FL
91
| P
ag
e
08
-Ju
n
A
23
.35
91
54
9
39
.50
6
0.9
22
82
7
16
.88
6
5.4
65
04
07
08
-Ju
n
B
25
.80
42
25
4
40
.14
3
1.0
35
85
9
16
.77
7
6.1
74
28
04
09
-Ju
n
C
-6.8
34
25
.41
12
67
6
39
.67
6
1.0
08
21
7
3.0
42
04
4
-
44
.51
33
82
16
.59
2
6.0
76
52
76
09
-Ju
n
A
23
.31
54
93
4
8.2
94
1
.12
59
98
2
2.1
03
5
.09
43
23
9
09
-Ju
n
B
23
.66
47
88
7
38
.36
2
0.9
07
82
9
16
.38
2
5.5
41
62
27
10
-Ju
n
C
-9.6
61
24
.58
16
90
1
36
.85
3
0.9
05
90
9
3.3
71
56
9
-
34
.89
87
53
21
.88
6
4.1
39
21
7
10
-Ju
n
A
24
.05
77
46
5
50
.46
1
.21
39
54
1
7.0
8
7.1
07
45
84
10
-Ju
n
B
24
.8
50
.47
2
1.2
51
70
6
21
.76
7
5.7
50
47
37
11
-Ju
n
C
1.1
08
24
.97
46
47
9
32
.74
2
0.8
17
72
2.6
67
95
2
24
0.7
89
9
17
.01
4
.80
72
89
4
11
-Ju
n
A
22
.39
85
91
5
51
.61
3
1.1
56
05
9
22
.17
7
5.2
12
87
15
11
-Ju
n
B
25
.49
85
91
5
27
.22
4
0.6
94
17
4
11
.01
4
6.3
02
64
81
12
-Ju
n
C
3.3
8
23
.66
47
88
7
49
.72
6
1.1
76
75
5
2.7
45
69
7
81
.23
36
26
16
.33
9
7.2
02
12
55
12
-Ju
n
A
23
.05
35
21
1
36
.71
1
0.8
46
31
8
16
.86
2
5.0
19
08
32
12
-Ju
n
B
20
.91
40
84
5
34
.55
2
0.7
22
62
3
21
.85
7
3.3
06
14
2
13
-Ju
n
C
16
.98
23
.14
08
45
1
23
.53
1
0.5
44
52
7
2.0
13
11
1
1.8
55
77
2
11
.49
4
4.7
37
49
11
13
-Ju
n
A
25
.67
32
39
4
20
.93
4
0.5
37
44
4
10
.73
5
.00
87
94
13
-Ju
n
B
22
.74
78
87
3
40
.93
3
0.9
31
13
9
17
.00
3
5.4
76
32
34
14
-Ju
n
C
-2.0
8
24
.14
50
70
4
54
.33
1
1.3
11
82
6
3.2
04
60
1
-
15
4.0
67
37
16
.71
8
7.8
46
78
68
14
-Ju
n
A
25
.41
12
67
6
36
.45
6
0.9
26
39
3
16
.43
3
5.6
37
39
53
14
-Ju
n
B
22
.66
05
63
4
42
.64
6
0.9
66
38
2
22
.4
4.3
14
20
71
15
-Ju
n
C
6.9
3
20
.17
18
31
4
6.7
67
0
.94
33
76
3.1
11
31
7
44
.89
63
54
21
.70
6
4.3
46
15
32
15
-Ju
n
A
25
.23
66
19
7
51
.02
1
1.2
87
59
8
22
.04
9
5.8
39
70
96
15
-Ju
n
B
23
.40
28
16
9
37
.61
7
0.8
80
34
4
16
.57
2
5.3
12
23
61
16
-Ju
n
C
11
.62
22
.52
95
77
5
44
.16
0
.99
49
06
2.8
13
58
1
24
.21
32
63
21
.89
5
4.5
43
98
79
16
-Ju
n
A
21
.35
07
04
2
50
.64
8
1.0
81
37
2
2.2
66
4
.85
65
99
6
16
-Ju
n
B
19
.38
59
15
5
38
.03
3
0.7
37
30
5
16
.62
1
4.4
35
98
17
17
-Ju
n
C
5.1
7
21
.56
90
14
1
24
.75
6
0.5
33
96
3
2.7
53
34
2
53
.25
61
33
19
.35
3
2.7
59
06
84
17
-Ju
n
A
22
.18
02
81
7
46
.78
6
1.0
37
72
7
23
.43
9
4.4
27
35
04
17
-Ju
n
B
23
.70
84
50
7
49
.84
1
1.1
81
65
3
10
.21
2
11
.57
12
19
92
| P
ag
e
S
od
a C
arr
yo
ve
r
C
om
bin
ed
Da
te
Sh
ift
To
tal
Loss
(MT
)
To
tal
So
da
Loss
(MT
)
% L
oss
in
So
da
Ca
rry
ov
er
%
Ge
ne
ral
Loss
%
Loss
(OR
E)
Av
g %
Loss
(OR
E)
RE
SU
LT
69
.59
5.1
08
01
-Ju
n
C
1.4
89
7
.06
41
45
4
74
.42
20
6
69
.59
5.1
9
5.1
08
01
-Ju
n
A
5.1
4
01
-Ju
n
B
5.7
0
02
-Ju
n
C
13
.64
1
6.4
47
39
3
47
.26
48
14
4.2
5
02
-Ju
n
A
5.3
4
02
-Ju
n
B
5.4
1
03
-Ju
n
C
10
.12
3
5.3
69
21
6
53
.03
97
72
5.1
7
03
-Ju
n
A
4.4
8
03
-Ju
n
B
4.3
1
04
-Ju
n
C
4.3
94
4
.98
66
66
1
13
.48
80
6
5.2
0
04
-Ju
n
A
5.1
3
04
-Ju
n
B
4.9
0
05
-Ju
n
C
17
.85
6
6.4
07
76
8
35
.88
57
98
4.7
5
05
-Ju
n
A
5.7
4
05
-Ju
n
B
5.1
9
06
-Ju
n
C
22
.41
9
6.7
00
88
7
29
.88
93
23
4.9
3
06
-Ju
n
A
4.8
7
06
-Ju
n
B
4.9
9
07
-Ju
n
C
22
.62
5
6.6
70
42
9
29
.48
25
57
4.6
7
07
-Ju
n
A
5.3
7
07
-Ju
n
B
5.6
6
08
-Ju
n
C
2.4
68
5
.54
21
63
2
24
.56
09
5
.05
08
-Ju
n
A
5.2
4
Ta
ble
7.3
. C
om
bin
ed
so
da
ca
rryo
ver
wit
h p
ulp
in S
FL a
nd
WFL
93
| P
ag
e
08
-Ju
n
B
5.0
9
09
-Ju
n
C
-6.8
34
6
.63
60
64
-9
7.1
03
65
5.2
2
09
-Ju
n
A
5.4
1
09
-Ju
n
B
5.1
8
10
-Ju
n
C
-9.6
61
6
.55
74
78
-6
7.8
75
77
4.3
6
10
-Ju
n
A
5.2
9
10
-Ju
n
B
5.9
4
11
-Ju
n
C
1.1
08
4
.30
33
71
3
88
.39
09
3
4.1
6
11
-Ju
n
A
7.5
2
11
-Ju
n
B
6.3
0
12
-Ju
n
C
3.3
8
5.2
10
80
8
15
4.1
65
91
4.9
1
12
-Ju
n
A
4.7
7
12
-Ju
n
B
4.2
5
13
-Ju
n
C
16
.98
5
.16
16
67
3
0.3
98
50
7
5.5
9
13
-Ju
n
A
5.1
9
13
-Ju
n
B
4.5
2
14
-Ju
n
C
-2.0
8
6.1
21
70
5
-29
4.3
12
7
6.5
4
14
-Ju
n
A
4.6
7
14
-Ju
n
B
4.3
9
15
-Ju
n
C
6.9
3
6.4
14
16
9
92
.55
65
53
4.3
8
15
-Ju
n
A
4.8
7
15
-Ju
n
B
5.1
1
16
-Ju
n
C
11
.62
6
.17
73
32
5
3.1
61
20
3
4.9
6
16
-Ju
n
A
4.6
9
16
-Ju
n
B
4.3
1
17
-Ju
n
C
5.1
7
6.5
23
60
1
12
6.1
81
84
4.3
1
17
-Ju
n
A
4.6
1
17
-Ju
n
B
7.3
2
Table 7.4. WFL production and total soda loss
WFL Period Production Soda Loss
Bleached
Pulp
(MT)
Weekly
Bleached
Production
Unbleached
Pulp (MT)
% Soda
(TTA
Na2O,
Kg/MT)
Soda Loss
(Weekly
basis MT)
01-Jan 81.11
532.956667
102.63
10.69718 7.1959951 02-Jan 85.71 99.23
03-Jan 61.59 86.44
04-Jan 88.6
648.62
88.72
10.60986 7.1888162
05-Jan 94.91 87.95
06-Jan 89 103.89
07-Jan 98.32 94.74
08-Jan 89.61 97.06
09-Jan 92.47 106.75
10-Jan 95.71 98.45
11-Jan 58.43
625.64
76.42
11.70141 8.2131016
12-Jan 92.3 96.79
13-Jan 98.13 115.43
14-Jan 96.14 102.42
15-Jan 87.55 99.28
16-Jan 97.42 113.05
17-Jan 95.67 98.5
18-Jan 94.53
657.45
112.23
14.62676 10.813418
19-Jan 97.33 100.44
20-Jan 90.21 109.23
21-Jan 95.77 110.11
22-Jan 92.38 90.94
23-Jan 96.56 94.29
24-Jan 90.67 122.05
25-Jan 80.33
637.33
108.46
11.30845 8.2252016
26-Jan 97.85 91.72
27-Jan 98.25 103.17
28-Jan 90.52 111.08
29-Jan 93.43 119.31
30-Jan 79.55 90.39
31-Jan 97.4 103.22
01-Feb 105.27
724.14
107.97
12.31268 9.9831177
02-Feb 106.83 127.9
03-Feb 105.45 109.46
04-Feb 106.24 120.15
05-Feb 92.04 99.57
06-Feb 105.13 123.91
07-Feb 103.18 121.84
08-Feb 100.65
596.93
111.63
15.1507 9.778416 09-Feb 96.73 105.47
10-Feb 42.99 28.24
11-Feb 39.84 64.06
95 | P a g e
12-Feb 105.2 107.69
13-Feb 105.33 114.13
14-Feb 106.19 114.19
15-Feb 103.11
706.83
116.56
17.55211 12.194506
16-Feb 92.4 104.67
17-Feb 90.01 108.41
18-Feb 105.68 107.92
19-Feb 106.32 42.64
20-Feb 106.75 120.11
21-Feb 102.56 94.45
22-Feb 83.72
708.29
111.02
22.79155 18.524743
23-Feb 98.37 131.3
24-Feb 103.83 112.87
25-Feb 94.26 105.23
26-Feb 108.73 115.22
27-Feb 110.31 113.96
28-Feb 109.07 123.19
01-Mar 109.48
754.42
121.25
18.9493 15.669931
02-Mar 110.65 116.04
03-Mar 92.54 108.33
04-Mar 111 126.83
05-Mar 109.36 128.31
06-Mar 110.59 118.77
07-Mar 110.8 107.41
08-Mar 108.13
665.29
110.65
19.34225 14.758139
09-Mar 70.74 84.59
10-Mar 91.16 110.28
11-Mar 107.62 121.58
12-Mar 87.57 107.8
13-Mar 102.06 109.9
14-Mar 98.01 118.2
15-Mar 114.4
753.03
118.61
18.20704 15.051762
16-Mar 106.32 112.63
17-Mar 112.28 118.45
18-Mar 101.94 133.76
19-Mar 96.44 106.16
20-Mar 112.47 115.07
21-Mar 109.18 122.02
22-Mar 104.05
733.89
105.81
18.42535 14.658289
23-Mar 109.73 121.33
24-Mar 112.95 120.9
25-Mar 100.11 122.24
26-Mar 108.14 112.06
27-Mar 106.21 112.61
28-Mar 92.7 100.6
29-Mar 95.53
619.73
115.04
19.42958 13.468195
30-Mar 79.76 94.62
31-Mar 52.31 71.82
01-Apr 98.02 74.91
02-Apr 83.34 99.6
96 | P a g e
03-Apr 100.5 117.66
04-Apr 110.27 119.53
05-Apr 76.3
728.38
91.28
20.7831 16.495961
06-Apr 110.1 128.84
07-Apr 110.02 106.25
08-Apr 110.73 121.03
09-Apr 110.81 129.43
10-Apr 104.47 121.57
11-Apr 105.95 95.32
12-Apr 90.2
682.72
108.52
21.48169 16.342411
13-Apr 102.45 114.53
14-Apr 103.83 121.37
15-Apr 84.99 103.43
16-Apr 103.18 94.44
17-Apr 99.26 108.28
18-Apr 98.81 110.19
19-Apr 100.04
616.88
109.16
23.75211 16.740964
20-Apr 90.35 107.38
21-Apr 99.37 106.41
22-Apr 98.04 108.93
23-Apr 91.17 109.3
24-Apr 77.29 97.88
25-Apr 60.62 65.76
26-Apr 83.82
644.18
95.34
24.97465 17.526209
27-Apr 96.58 105.71
28-Apr 101.17 111.61
29-Apr 70.5 83.49
30-Apr 96.34 110.99
01-May 94.98 97.23
02-May 100.79 97.39
03-May 100.15
711.36
109.28
22.57324 17.758367
04-May 100.49 110.16
05-May 103.13 109.58
06-May 103.26 122.74
07-May 103.67 106.09
08-May 96 114.87
09-May 104.66 113.98
10-May 104.13
762.86
119.7
19.95352 17.341805
11-May 105.23 105.92
12-May 102 155.33
13-May 112.35 113.03
14-May 114.04 135.51
15-May 112.58 118.09
16-May 112.53 121.53
17-May 106.11
677.4
120.6
21.39437 16.610158
18-May 60.55 74.83
19-May 104.61 115.98
20-May 98.5 104.95
21-May 92.66 122.96
22-May 108.66 108.84
97 | P a g e
23-May 106.31 128.22
24-May 68.06
668.77
101.92
23.27183 17.395461
25-May 86.78 73.13
26-May 111.82 103.35
27-May 114.36 126.26
28-May 74.82 88.14
29-May 110.89 130.71
30-May 102.04 123.98
31-May 110.02 770.14 112.24 23.5338 18.490038
98 | P a g e
Table 7.4. SFL production and total soda loss
SFL Period Production Soda Loss
Bleached
Pulp
(MT)
Weekly
Bleached
Production
Unbleached
Pulp (MT)
Weekly
Unbleached
Pulp (MT)
% Soda
(TTA
Na2O,
Kg/MT)
Soda Loss
(Weekly
basis MT)
01-Jan 210.9
1128.26
267.36
1508.243333 17.94507 27.065533 02-Jan 161.76 218.92
03-Jan 110.88 160.11
04-Jan 190.81
1364.54
134.03
1395.77 14.88873 20.781246
05-Jan 195.73 198.33
06-Jan 173.98 234.3
07-Jan 124.68 127.86
08-Jan 255.84 268.38
09-Jan 203.76 213.35
10-Jan 219.74 219.52
11-Jan 175.76
1446.65
165.62
1469.37 17.3338 25.46977
12-Jan 226.86 240.51
13-Jan 198.93 193.95
14-Jan 226.01 244.67
15-Jan 241.11 239.17
16-Jan 150.85 177.26
17-Jan 227.13 208.19
18-Jan 217.41
1532.29
231.07
1583.97 17.11549 27.110427
19-Jan 234.27 209.28
20-Jan 204.78 232.66
21-Jan 207.34 215.89
22-Jan 225.1 227.42
23-Jan 216.96 219.44
24-Jan 226.43 248.21
25-Jan 135.45
1368.06
228.4
1532.89 14.80141 22.688931
26-Jan 170.71 206.68
27-Jan 211.03 199.6
28-Jan 200.98 236.3
29-Jan 183.38 189.29
30-Jan 226.45 222.03
31-Jan 240.06 250.59
01-Feb 202.779
1374.019
237.27
1418.87 15.10704 21.434929
02-Feb 211.93 204.82
03-Feb 198.86 237.81
04-Feb 190.08 196.68
05-Feb 169.13 173.78
06-Feb 179.18 142.06
07-Feb 222.06 226.45
08-Feb 205.01
1151.77
212.54
1220.48 15.41268 18.810863 09-Feb 205.91 203.57
10-Feb 57.1 96.44
11-Feb 81.83 52.83
99 | P a g e
12-Feb 192.16 208.4
13-Feb 194.78 210.22
14-Feb 214.98 236.48
15-Feb 145.29
1322.98
198.25
1444.47 18.6 26.867142
16-Feb 189.83 162.34
17-Feb 165.1 198.59
18-Feb 196.56 176.79
19-Feb 193.63 258.11
20-Feb 220.43 234.16
21-Feb 212.14 216.23
22-Feb 205.08
1473.11
196.82
1641.5 15.67465 25.729935
23-Feb 233.91 211.89
24-Feb 205.41 223.29
25-Feb 223.68 249.81
26-Feb 177.19 279.19
27-Feb 225.35 231.51
28-Feb 202.49 248.99
01-Mar 186.42
1535.62
218.26
1651.4 14.40845 23.794115
02-Mar 220.63 235.87
03-Mar 227.64 244.09
04-Mar 230.68 231.93
05-Mar 240.33 241.53
06-Mar 232.86 231.83
07-Mar 197.06 247.89
08-Mar 179.58
1220.72
180.96
1441.13 15.76197 22.71505
09-Mar 215.88 195.55
10-Mar 216.81 296.68
11-Mar 215.2 262.92
12-Mar 85.61 86.6
13-Mar 125.51 151.98
14-Mar 182.13 266.44
15-Mar 224.06
1424.72
230
1619.24 16.32958 26.441505
16-Mar 168.05 230.41
17-Mar 181.68 224.24
18-Mar 180.98 228.82
19-Mar 271.06 237.96
20-Mar 221.41 253.84
21-Mar 177.48 213.97
22-Mar 198.61
1479.99
223.67
1570.94 16.94085 26.613051
23-Mar 223.51 211
24-Mar 268.87 272.71
25-Mar 204.16 216.14
26-Mar 204.65 226.19
27-Mar 218.66 241.23
28-Mar 161.53 180
29-Mar 303.02
1481.47
341.12
1662.56 14.93239 24.826002
30-Mar 99.52 135.44
31-Mar 211.08 247.62
01-Apr 208.3 186.76
02-Apr 221.63 251.49
100 | P a g e
03-Apr 225.83 267.71
04-Apr 212.09 232.42
05-Apr 175
1455.96
230.41
1714.69 13.3169 22.834358
06-Apr 223.82 257.37
07-Apr 227.31 258.7
08-Apr 210.9 244.38
09-Apr 228.28 263.2
10-Apr 190.29 220.63
11-Apr 200.36 240
12-Apr 230.92
1479.51
240
1568.35 16.02394 25.131152
13-Apr 177.93 200.59
14-Apr 211.74 216.3
15-Apr 231.06 253
16-Apr 221.66 228.21
17-Apr 170.44 174.36
18-Apr 235.76 255.89
19-Apr 163.16
1340.79
190.61
1508.17 16.15493 24.36438
20-Apr 147.35 158.05
21-Apr 206.49 242.1
22-Apr 200.81 213.52
23-Apr 197.49 239.43
24-Apr 210.53 229.05
25-Apr 214.96 235.41
26-Apr 225.53
1490.34
239.62
1678.42 16.19859 27.18804
27-Apr 98.84 124.72
28-Apr 213.6 243.13
29-Apr 236.3 257.99
30-Apr 239.23 272.63
01-May 244.69 268
02-May 232.15 272.33
03-May 171.13
1589.17
185.68
1782.65 16.80986 29.966095
04-May 241.09 271.98
05-May 227.04 252.06
06-May 226.18 247.94
07-May 242.45 278.68
08-May 238.14 271.53
09-May 243.14 274.78
10-May 220.75
1677.12
230.59
1893.33 17.72676 33.562608
11-May 238.63 277.73
12-May 240.56 276.94
13-May 245.45 269.35
14-May 245 276.22
15-May 245.93 277.99
16-May 240.8 284.51
17-May 205.36
1449.36
248.82
1657.66 17.72676 29.384942
18-May 224 225.06
19-May 205 230.97
20-May 193 227.64
21-May 204 216.8
22-May 222 258.59
101 | P a g e
23-May 196 249.78
24-May 46
1292.02
73.6
1460.52 16.7662 24.487366
25-May 210.01 222.13
26-May 224.01 172.54
27-May 208 331.46
28-May 169 172.18
29-May 210 241.17
30-May 225 247.44
31-May 222 1554 255.97 1791.79 13.70986 24.565189
Ta
ble
8.1
. So
da
loss
fro
m S
cre
en
s a
s R
eje
ct in
WFL
an
d S
FL
Scr
ee
n L
oss
SF
L W
FL
Da
te
Sh
ift
To
tal
Loss
(MT
)
TT
A
(Na
2C
O3
)
% T
ota
l
So
da
(T
TA
Na
2O
,
Kg
/MT
)
%
Wa
sha
ble
So
da
lo
ss
Ma
ss o
f
Pu
lp
(MT
)
To
tal
So
da
Loss
(MT
)
To
tal
Wa
sha
ble
So
da
Lo
ss
(MT
)
% T
ota
l
So
da
(T
TA
Na
2O
,
Kg
/MT
)
%
Wa
sha
ble
So
da
lo
ss
Ma
ss o
f
Pu
lp
(MT
)
To
tal
So
da
Loss
(MT
)
To
tal
Wa
sha
ble
So
da
Lo
ss
(MT
)
RE
SU
LT
01
-Ju
n
C
1.4
89
33
.3
52
.76
5
0.9
2
.59
46
0
.13
68
91
0
.13
20
65
1
81
.82
5
6.2
9
1.3
66
92
0
.11
18
41
0
.07
69
43
9
01
-Ju
n
A
31
.9
01
-Ju
n
B
34
.6
02
-Ju
n
C
13
.64
1
32
.9
52
.76
5
0.9
2
.52
08
0
.13
29
97
0
.12
83
08
7
81
.82
5
6.2
9
1.2
37
65
0
.10
12
65
0
.06
96
67
3
02
-Ju
n
A
34
.5
02
-Ju
n
B
29
.6
03
-Ju
n
C
10
.12
3
28
.4
52
.76
5
0.9
2
.43
35
0
.12
83
91
0
.12
38
65
2
81
.82
5
6.2
9
1.0
89
75
0
.08
91
63
0
.06
13
42
0
3-J
un
A
2
6.3
03
-Ju
n
B
27
.1
04
-Ju
n
C
4.3
94
29
.3
52
.76
5
0.9
1
.98
61
0
.10
47
87
0
.10
10
92
5
81
.82
5
6.2
9
1.0
28
76
0
.08
41
73
0
.05
79
08
9
04
-Ju
n
A
27
.2
04
-Ju
n
B
29
.6
05
-Ju
n
C
17
.85
6
29
.8
52
.76
5
0.9
2
.63
1
0.1
38
81
2
0.1
33
91
79
8
1.8
2
56
.29
1
.49
19
6
0.1
22
07
2
0.0
83
98
24
0
5-J
un
A
2
9.4
05
-Ju
n
B
33
.2
06
-Ju
n
C
22
.41
9
34
.1
52
.76
5
0.9
2
.61
29
0
.13
78
57
0
.13
29
96
6
81
.82
5
6.2
9
1.5
01
65
6
0.1
22
86
5
0.0
84
52
82
0
6-J
un
A
3
0.4
06
-Ju
n
B
33
.4
07
-Ju
n
C
22
.62
5
29
.2
52
.76
5
0.9
2
.55
3
0.1
34
69
6
0.1
29
94
77
8
1.8
2
56
.29
1
.55
08
44
0
.12
68
9
0.0
87
29
7
07
-Ju
n
A
31
.4
07
-Ju
n
B
32
.7
08
-Ju
n
C
2.4
68
3
3.3
5
2.7
6
50
.9
2.3
01
8
0.1
21
44
3
0.1
17
16
16
8
1.8
2
56
.29
1
.22
04
96
0
.09
98
61
0
.06
87
01
7
10
3 |
Pa
ge
08
-Ju
n
A
29
.6
08
-Ju
n
B
29
.2
09
-Ju
n
C
-6.8
34
32
.9
52
.76
5
0.9
2
.53
86
0
.13
39
37
0
.12
92
14
7
81
.82
5
6.2
9
1.5
15
98
4
0.1
24
03
8
0.0
85
33
47
0
9-J
un
A
3
3.7
09
-Ju
n
B
30
.8
10
-Ju
n
C
-9.6
61
28
.6
52
.76
5
0.9
2
.41
51
0
.12
74
21
0
.12
29
28
6
81
.82
5
6.2
9
1.6
53
42
0
.13
52
83
0
.09
30
71
1
0-J
un
A
2
9.4
10
-Ju
n
B
33
.1
11
-Ju
n
C
1.1
08
26
.8
52
.76
5
0.9
1
.26
24
0
.06
66
04
0
.06
42
56
2
81
.82
5
6.2
9
1.3
38
94
8
0.1
09
55
3
0.0
75
36
94
1
1-J
un
A
3
3.4
11
-Ju
n
B
0
12
-Ju
n
C
3.3
8
27
.8
52
.76
5
0.9
1
.76
38
0
.09
30
58
0
.08
97
77
4
81
.82
5
6.2
9
1.4
51
86
8
0.1
18
79
2
0.0
81
72
56
1
2-J
un
A
3
0.8
12
-Ju
n
B
34
.4
13
-Ju
n
C
16
.98
35
.4
52
.76
5
0.9
2
.29
77
0
.12
12
27
0
.11
69
52
9
81
.82
5
6.2
9
1.0
24
77
6
0.0
83
84
7
0.0
57
68
46
1
3-J
un
A
2
9.5
13
-Ju
n
B
27
.8
14
-Ju
n
C
-2.0
8
30
.2
52
.76
5
0.9
2
.22
36
0
.11
73
17
0
.11
31
81
2
81
.82
5
6.2
9
1.6
01
19
6
0.1
31
01
0
.09
01
31
3
14
-Ju
n
A
30
.2
14
-Ju
n
B
29
.8
15
-Ju
n
C
6.9
3
28
.8
52
.76
5
0.9
2
.67
25
0
.14
10
01
0
.13
60
30
3
81
.82
5
6.2
9
1.6
24
86
0
.13
29
46
0
.09
14
63
4
15
-Ju
n
A
28
.2
15
-Ju
n
B
27
.9
16
-Ju
n
C
11
.62
32
52
.76
5
0.9
2
.60
67
0
.13
75
29
0
.13
26
81
8
1.8
2
56
.29
1
.59
40
92
0
.13
04
29
0
.08
97
31
4
16
-Ju
n
A
29
.2
16
-Ju
n
B
27
.3
17
-Ju
n
C
5.1
7
34
.6
52
.76
5
0.9
2
.85
28
0
.15
05
14
0
.14
52
07
5
81
.82
5
6.2
9
1.4
56
59
6
0.1
19
17
9
0.0
81
99
18
1
7-J
un
A
2
9.4
17
-Ju
n
B
26
.7
10
4 |
Pa
ge
Ta
ble
8.2
. C
om
bin
ed
so
da
loss
fro
m S
cre
en
s a
s R
eje
ct in
WFL
an
d S
FL
Scr
ee
n L
oss
Co
mb
ine
d
Da
te
Sh
ift
To
tal
Loss
(MT
)
TT
A
(Na
2
CO
3)
To
tal
So
da
Loss
(MT
)
To
tal
Wa
sha
ble
So
da
Lo
ss
(MT
)
% T
ota
l
Loss
in
Scr
ee
n
%
Wa
sha
ble
Loss
in
Scr
ee
n
%
Ge
ne
ral
To
tal
So
da
Loss
%
Ge
ne
ral
Wa
sha
b
le S
od
a
Loss
% L
oss
for
To
tal
So
da
(OR
E)
Av
g %
Loss
fo
r
To
tal
So
da
(OR
E)
% L
oss
fo
r
Wa
sha
ble
So
da
(OR
E)
Av
g %
Loss
fo
r
Wa
sha
ble
So
da
(OR
E)
RE
SU
LT
2
.81
2
.34
0.2
01
0.1
67
01
-Ju
n
C
1.4
89
33
.3
0.2
48
73
2
0.2
09
00
91
1
6.7
04
67
1
4.0
36
87
49
2.8
09
2
.34
0
0.1
87
17
4
0.2
01
0.1
57
28
14
0.1
67
01
-Ju
n
A
31
.9
01
-Ju
n
B
34
.6
02
-Ju
n
C
13
.64
1
32
.9
0.2
34
26
2
0.1
97
97
6
1.7
17
33
7
1.4
51
33
08
3
0.1
81
29
2
0.1
53
21
08
0
2-J
un
A
3
4.5
02
-Ju
n
B
29
.6
03
-Ju
n
C
10
.12
3
28
.4
0.2
17
55
5
0.1
85
20
72
2
.14
91
14
1
.82
95
68
09
0
.18
75
31
0
.15
96
47
3
03
-Ju
n
A
26
.3
03
-Ju
n
B
27
.1
04
-Ju
n
C
4.3
94
29
.3
0.1
88
96
0
.15
90
01
4
4.3
00
40
5
3.6
18
60
24
2
0.1
92
98
6
0.1
62
38
92
0
4-J
un
A
2
7.2
04
-Ju
n
B
29
.6
05
-Ju
n
C
17
.85
6
29
.8
0.2
60
88
4
0.2
17
90
03
1
.46
10
42
1
.22
03
19
94
0
.21
27
19
0
.17
76
71
5
05
-Ju
n
A
29
.4
05
-Ju
n
B
33
.2
06
-Ju
n
C
22
.41
9
34
.1
0.2
60
72
2
0.2
17
52
48
1
.16
29
52
0
.97
02
69
98
0
.19
20
05
0
.16
01
92
7
06
-Ju
n
A
30
.4
06
-Ju
n
B
33
.4
07
-Ju
n
C
22
.62
5
29
.2
0.2
61
58
6
0.2
17
24
47
1
.15
61
83
0
.96
01
97
61
0
.20
45
07
0
.16
98
40
6
07
-Ju
n
A
31
.4
10
5 |
Pa
ge
07
-Ju
n
B
32
.7
08
-Ju
n
C
2.4
68
33
.3
0.2
21
30
4
0.1
85
86
33
8
.96
69
35
7
.53
09
29
49
0
.20
50
11
0
.17
21
79
2
08
-Ju
n
A
29
.6
08
-Ju
n
B
29
.2
09
-Ju
n
C
-6.8
34
32
.9
0.2
57
97
4
0.2
14
54
95
-3
.77
48
7
-3.1
39
44
22
0
.20
51
17
0
.17
05
89
6
09
-Ju
n
A
33
.7
09
-Ju
n
B
30
.8
10
-Ju
n
C
-9.6
61
28
.6
0.2
62
70
4
0.2
15
99
96
-2
.71
92
2
-2.2
35
78
93
0
.20
64
52
0
.16
97
48
9
10
-Ju
n
A
29
.4
10
-Ju
n
B
33
.1
11
-Ju
n
C
1.1
08
26
.8
0.1
76
15
7
0.1
39
62
55
1
5.8
98
64
1
2.6
01
58
33
0
.22
96
4
0.1
82
01
75
1
1-J
un
A
3
3.4
11
-Ju
n
B
0
12
-Ju
n
C
3.3
8
27
.8
0.2
11
85
0
.17
15
03
1
6.2
67
74
9
5.0
74
05
53
2
0.1
87
15
7
0.1
51
51
25
1
2-J
un
A
3
0.8
12
-Ju
n
B
34
.4
13
-Ju
n
C
16
.98
35
.4
0.2
05
07
4
0.1
74
63
76
1
.20
77
37
1
.02
84
89
82
0
.20
21
4
0.1
72
13
91
1
3-J
un
A
2
9.5
13
-Ju
n
B
27
.8
14
-Ju
n
C
-2.0
8
30
.2
0.2
48
32
7
0.2
03
31
26
-1
1.9
38
8
-9.7
74
64
24
0
.20
82
3
0.1
70
48
41
1
4-J
un
A
3
0.2
14
-Ju
n
B
29
.8
15
-Ju
n
C
6.9
3
28
.8
0.2
73
94
7
0.2
27
49
36
3
.95
30
61
3
.28
27
36
21
0
.20
34
29
0
.16
89
33
1
5-J
un
A
2
8.2
15
-Ju
n
B
27
.9
16
-Ju
n
C
11
.62
32
0.2
67
95
8
0.2
22
41
25
2
.30
60
08
1
.91
40
48
78
0
.20
23
46
0
.16
79
52
7
16
-Ju
n
A
29
.2
16
-Ju
n
B
27
.3
17
-Ju
n
C
5.1
7
34
.6
0.2
69
69
2
0.2
27
19
93
5
.21
64
88
4
.39
45
70
77
0
.21
36
95
0
.18
00
25
1
7-J
un
A
2
9.4
17
-Ju
n
B
26
.7
Ta
ble
9.6
. E
SP O
RE
Lo
ss
Re
cov
ery
2
Re
cov
ery
1
To
tal
W
FL
SFL
Da
te
Sh
ift
To
tal
Loss
(MT
)
WL
Co
nsu
me
d
(TT
A N
a2
O
MT
)
WL
Co
nsu
me
d
(TT
A N
a2
O
MT
)
% L
oss
(OR
E)
Av
g %
Loss
(OR
E)
% L
oss
thro
ug
h
ES
P
%
Ge
ne
ral
Loss
tho
ug
h
ES
P
% L
oss
(OR
E)
Av
g %
Loss
(OR
E)
% L
oss
thro
ug
h
ES
P
%
Ge
ne
ral
Loss
tho
ug
h
ES
P
Av
g %
Loss
(OR
E)
%
Ge
ne
ral
Loss
tho
ug
h
ES
P
RE
SU
LT
0
.81
7
1
1.4
8
0
.58
0
8
.15
1
.39
7
19
.63
01
-Ju
n
C
1.4
9
21
.8
25
.0
0.7
2
0.8
2
64
.08
11
.48
0.5
1
0.5
8
45
.53
8.1
5
1.4
0
19
.63
01
-Ju
n
A
22
.3
26
.2
01
-Ju
n
B
16
.4
21
.2
02
-Ju
n
C
13
.64
16
.9
27
.5
0.7
4
6.9
9
0.5
2
4.9
7
02
-Ju
n
A
21
.7
24
.7
02
-Ju
n
B
16
.4
22
.0
03
-Ju
n
C
10
.12
16
.6
18
.7
0.8
2
9.4
3
0.5
8
6.7
0
03
-Ju
n
A
16
.9
21
.3
03
-Ju
n
B
16
.7
25
.8
04
-Ju
n
C
4.3
9
17
.1
22
.6
0.9
7
21
.71
0
.69
1
5.4
3
04
-Ju
n
A
16
.9
13
.4
04
-Ju
n
B
11
.2
16
.7
05
-Ju
n
C
17
.86
16
.7
24
.2
0.7
8
5.3
4
0.5
5
3.8
0
05
-Ju
n
A
16
.8
23
.6
05
-Ju
n
B
16
.6
24
.6
06
-Ju
n
C
22
.42
16
.2
28
.4
0.7
0
4.2
6
0.5
0
3.0
2
06
-Ju
n
A
17
.2
24
.6
06
-Ju
n
B
22
.1
27
.4
07
-Ju
n
C
22
.63
22
.4
23
.2
0.7
5
4.2
2
0.5
3
3.0
0
07
-Ju
n
A
16
.6
24
.2
07
-Ju
n
B
16
.9
24
.6
10
7 |
Pa
ge
08
-Ju
n
C
2.4
7
11
.4
19
.6
0.8
8
38
.66
0
.63
2
7.4
7
08
-Ju
n
A
16
.9
20
.2
08
-Ju
n
B
16
.8
23
.2
09
-Ju
n
C
-6.8
3
16
.6
25
.0
0.7
6
-13
.96
0
.54
-9
.92
09
-Ju
n
A
22
.1
21
.4
09
-Ju
n
B
16
.4
24
.3
10
-Ju
n
C
-9.6
6
21
.9
23
.6
0.7
5
-9.8
8
0.5
3
-7.0
2
10
-Ju
n
A
17
.1
26
.2
10
-Ju
n
B
21
.8
16
.7
11
-Ju
n
C
1.1
1
17
.0
22
.7
1.2
4
86
.11
0
.88
6
1.1
9
11
-Ju
n
A
22
.2
3.8
11
-Ju
n
B
11
.0
0.0
12
-Ju
n
C
3.3
8
16
.3
12
.6
0.8
4
28
.23
0
.60
2
0.0
6
12
-Ju
n
A
16
.9
23
.5
12
-Ju
n
B
21
.9
22
.1
13
-Ju
n
C
16
.98
11
.5
23
.3
0.9
4
5.6
2
0.6
7
3.9
9
13
-Ju
n
A
10
.7
19
.4
13
-Ju
n
B
17
.0
19
.5
14
-Ju
n
C
-2.0
8
16
.7
19
.7
0.8
0
-45
.87
0
.57
-3
2.6
0
14
-Ju
n
A
16
.4
19
.2
14
-Ju
n
B
22
.4
24
.9
15
-Ju
n
C
6.9
3
21
.7
25
.8
0.7
1
13
.77
0
.50
9
.78
15
-Ju
n
A
22
.0
27
.0
15
-Ju
n
B
16
.6
21
.5
16
-Ju
n
C
11
.62
21
.9
23
.3
0.7
2
8.2
1
0.5
1
5.8
3
16
-Ju
n
A
22
.3
25
.0
16
-Ju
n
B
16
.6
23
.4
17
-Ju
n
C
5.1
7
19
.4
26
.8
0.7
6
18
.45
0
.54
1
3.1
1
17
-Ju
n
A
23
.4
25
.4
17
-Ju
n
B
10
.2
20
.9
Table 10.1. Average ORE based on stock
SFL WFL
Date Shift
Total
Loss
(MT)
WL
Consumed
(TTA
Na2O MT)
WL
Consumed
(TTA
Na2O MT)
Total WL
Consumed % Loss ORE
Average
ORE
01-Jun C
1.489
24.98705 21.845 46.83205
1.1205 98.88 94.0003
01-Jun A 26.1545 22.28 48.4345
01-Jun B 21.1951 16.427 37.6221
02-Jun C
13.641
27.47343 16.923 44.39643
10.557 89.443 02-Jun A 24.6942 21.713 46.4072
02-Jun B 22.0274 16.387 38.4144
03-Jun C
10.123
18.66867 16.616 35.28467
8.726 91.274 03-Jun A 21.32362 16.904 38.22762
03-Jun B 25.78394 16.714 42.49794
04-Jun C
4.394
22.63644 17.094 39.73044
4.4876 95.512 04-Jun A 13.41116 16.891 30.30216
04-Jun B 16.7262 11.155 27.8812
05-Jun C
17.856
24.22728 16.749 40.97628
14.559 85.441 05-Jun A 23.63286 16.811 40.44386
05-Jun B 24.60912 16.613 41.22212
06-Jun C
22.419
28.35826 16.183 44.54126
16.51 83.49 06-Jun A 24.55047 17.197 41.74747
06-Jun B 27.35278 22.148 49.50078
07-Jun C
22.625
23.20928 22.443 45.65228
17.688 82.312 07-Jun A 24.21172 16.555 40.76672
07-Jun B 24.62994 16.862 41.49194
08-Jun C
2.468
19.581 11.354 30.935
2.2863 97.714 08-Jun A 20.15745 16.886 37.04345
08-Jun B 23.19216 16.777 39.96916
09-Jun C
-6.834
24.9565 16.592 41.5485
-5.434 105.43 09-Jun A 21.44608 22.103 43.54908
09-Jun B 24.28979 16.382 40.67179
10-Jun C
-9.661
23.60832 21.886 45.49432
-7.592 107.59 10-Jun A 26.16104 17.08 43.24104
10-Jun B 16.74419 21.767 38.51119
11-Jun C
1.108
22.67496 17.01 39.68496
1.4444 98.556 11-Jun A 3.834 22.177 26.011
11-Jun B 0 11.014 11.014
12-Jun C
3.38
12.61416 16.339 28.95316
2.986 97.014 12-Jun A 23.46552 16.862 40.32752
12-Jun B 22.0563 21.857 43.9133
13-Jun C
16.98
23.2686 11.494 34.7626
16.737 83.263 13-Jun A 19.43172 10.73 30.16172
13-Jun B 19.52412 17.003 36.52712
14-Jun C -2.08 19.67256 16.718 36.39056 -1.744 101.74
109 | P a g e
14-Jun A 19.15182 16.433 35.58482
14-Jun B 24.88068 22.4 47.28068
15-Jun C
6.93
25.8447 21.706 47.5507
5.1461 94.854 15-Jun A 26.99169 22.049 49.04069
15-Jun B 21.5016 16.572 38.0736
16-Jun C
11.62
23.2848 21.895 45.1798
8.7747 91.225 16-Jun A 24.98796 22.266 47.25396
16-Jun B 23.3709 16.621 39.9919
17-Jun C
5.17
26.8422 19.353 46.1952
4.0965 95.903 17-Jun A 25.43688 23.439 48.87588
17-Jun B 20.92122 10.212 31.13322
