Project Report

On

“An Overview of the Fluidised

Catalytic Cracking Petroleum

Complex”

Undertaken at

Guru Gobind Singh Refinery, HMEL, Bathinda

June-July, 2013

Submitted to: Submitted by:Shobhan Mehta Amit Khosla Head Training, GGSR Dr. S.S.B.U.I.C.E.T HMEL, Bathinda Panjab University, Chandigarh

CERTIFICATE

This is to certify that Mr Amit Khosla, a student of Dr. S.S.B.U.I.C.E.T, Panjab University, Chandigarh pursuing B.E. Chemical Engineering with M.B.A has successfully completed his industrial training project during the period 03/06/2013 to 12/07/2013 at the Guru Gobind Singh refinery, Bathinda. His behaviour and conduct was good and he maintained punctuality during the industrial training. I wish him success in all his future endeavours.

A certificate may kindly be issued to him regarding the same.

Shobhan Mehta Head Training, GGSR

HMEL, Bathinda

Acknowledgement

I am indebted to HMEL management for providing me an opportunity to work on the

project “An Overview of the Fluidised Catalytic Cracking Petroleum Complex”

at the GGSR, Bathinda.

I would like to express my deep sense of gratitude to Shri Ravi Yadav, HR Manager,

HMEL for providing me such a privileged opportunity to work at the Guru Gobind

Singh Refinery.

I also acknowledge my profound gratitude to Shri Shobhan Mehta, Head, Training,

GGSR, for providing me every kind of technical assistance, valuable counselling,

support and co-operation during the entire course of this project.

I am also thankful to the HR dept., especially Ms. Navjeet Gill and Mr. Vikas Mehta

Assistant Managers at HPCL Mittal Energy Limited, GGSR, Bathinda for their help

and cooperation during the stay at GGSR.

Lastly, I would also like to acknowledge the efforts of the staff at the refinery and the

training department and other trainees who directly or indirectly helped me during

this industrial training for successfully completing my project and making it a grand

success.

Amit Khosla

Table of Contents

ABSTRACT.......................................................................................................................................1

About HMEL.............................................................................................................................2

HMEL Core Values.................................................................................................................3

Corporate Social Responsibility............................................................................................3

Guru Gobind Singh Refinery.............................................................................................6

Products & Services...............................................................................................................7

Fluidised Catalytic Cracking Petrochemical Complex.........................................15

FEED......................................................................................................................................17

REACTOR COLUMN...........................................................................................................17

CATALYST............................................................................................................................19

REGENERATION COLUMN...............................................................................................19

MAIN FRACTIONATOR.......................................................................................................20

GAS CONCENTRATION (GASCON)................................................................................22

PROPYLENE RECOVERY UNIT (PRU).........................................................................23

CONCLUSION........................................................................................................................25

REFERENCES.......................................................................................................................25

Table of Figures

Figure 1: Indian Oil Industry Structure……………………………………………2

Figure 2: GURU GOBIND SINGH REFINERY CONFIGURATION…………….14

Figure 3: Feed and Products of FCCPC…………………………………………16

Figure 4: Position of FCCPC in the Refinery……………………………………16

Figure 5: Flow Chart of the Conversion Section……………………………….17

Figure 6: Schematic Showing the Catalyst in Action…………………………19

Figure 7: Schematic Showing the Convertor Section……………..................20

Figure 8: Salient Features of the Equipment Employed in FCCPC………...22

Figure 9: Schematic of the MF & Gas Plant……………………………………..23

Figure 10: Schematic of the Propylene Recovery Unit (PRU)……………….24

ABSTRACT

HPCL-Mittal Energy Limited (HMEL) is a joint venture between Hindustan

Petroleum Corporation Limited (HPCL) and Mittal Energy Investment Pte Ltd,

Singapore - a Lakshmi N Mittal Group Company. The land mark public-private

partnership company has built the 9 MMTPA Guru Gobind Singh Refinery (GGSR).

The refinery since its operation has commenced has been operating the many units

among which the Fluidised Catalytic Cracking Petroleum Complex (FCCPC) is

considered the most economically essential unit. The production of this plant is 2.22

MMTPA, which includes the petroleum product Propylene. The unit employed at

GGSR is a Deep Catalytic Cracking unit, which is slightly different from Fluidised

catalytic cracking unit in terms of the yield and complexity. The major products of

FCCPC include Propylene which goes to Propylene Recovery Unit (PRU), Light

Cracked Naphtha (LCN) and Mild Cracked Naphtha (MCN), which are used to

gasoline blending in MS block. The Objective of this Project Report has been to

briefly describe the important sub-units of FFCPC at GGSR and their functioning.

1

About HMEL HPCL-Mittal Energy Limited (HMEL) is a joint venture between Hindustan Petroleum

Corporation Limited (HPCL) and Mittal Energy Investment Pte Ltd, Singapore - a

Lakshmi N Mittal Group Company. Both the JV partners hold a stake of 49% each in

the company, the rest 2% is held by financial institutions. The land mark public-

private partnership company has built the 9 MMTPA Guru Gobind Singh Refinery.

The refinery is located at village Phullokhari in Bathinda district of Punjab. It has a

pipeline of length approx. 1014 km from Mundra to Bathinda and a Single Point

Mooring (SPM) buoy capable of handling Very Large Crude Carriers (VLCC) for

crude imports at Mundra, a Crude Oil Terminal (COT) approximately six kms away

from the seashore at Mundra, Gujarat and a captive power plant of 165 MW for the

refinery’s power and steam requirements.

The enormity of the Guru Gobind Singh Refinery project makes it the single largest

investment at any location in Punjab. It is the first oil and gas project to be set up in

the state. The refinery will produce petroleum products complying with Euro IV

emission norms.

The refinery is a zero bottom plant, with a Nelson Complexity Index of 10.7.

Figure 1: Indian Oil Industry Structure

2

HMEL Core Values

HMEL is governed by six core Values. These values are of highest priority for the

organisation and deeply held driving forces. 

The six HMEL Core Values are:

Safety First

Achieve Targets and Meet Deadlines

High Ethical Standards

Respect for People

Continuous Improvement and Learning

Teamwork

Corporate Social Responsibility

Corporate Social Responsibility forms an integral part of HMEL.  HMEL recognizes

their responsibility towards the society in which they operate. It is an active and

involved part of our community. HMEL is committed to being a good corporate

citizen and contributing to the well-being of the region and the province in which it

operates. HMEL has undertaken several large and small projects aimed at the

development of community in and around Project sites.

Education

HMEL strongly believes that education will have a positive impact on our country’s

readiness for a promising future.

Making a beginning, HMEL has partnered with ‘Pratham’, a leading NGO in the field

of Primary education to provide elementary education to the children of labourer

deployed in construction of Refinery. Two types of classes have been initiated under

this partnership viz  Balwadi – for children aged between three and five and Learn to

Read ( L2R) for children above five years of age. Recently school uniforms were

distributed to the students of Pratham.

For ensuring continuation of education to under privileged children, three evening

Schools which were at the verge of closing due to lack of funds have been adopted

by HMEL in Bathinda City. These schools are managed by Red Cross Society and

are located near slum area.

3

Skill Building and Employment

In an effort towards providing the local youth of Punjab with employment opportunity

and giving them a meaningful direction for growth and development, HMEL in

association with Construction Industry Development Council (CIDC) an autonomous

body under the Planning Commission of the Government of India has sponsored the

Construction Skills Training Centre at village Phulokhari. This centre is providing

training to the youth of adjoining villages of the project site in technical skills required

for refinery construction like masonry, bar bender and shuttering carpentry. Youth is

being selected by the help of District Administration.

In addition to this, HMEL with National Academy of Construction (NAC), Hyderabad

is also providing training in welding to candidates from the adjoining villages of the

site. Furthermore to generate employment opportunities for youths, on successful

completion of the training the trainees are being deployed for various civil jobs with

different contractors working at the Project site.

Health, Community and Environment

HMEL believes in collaborating with people in the community they operate and

dedicate to raising standards of health & overall well-being and work towards

continually conserving & strengthening of Environment. They are engaged in various

health, hygiene, community development and environment conservation initiatives

such as:-

Health

Conducting periodic health check-up including Pulse Polio immunization,

vaccinations etc. for various labour colonies in and around the refinery site.

Eye camps being organized for labourer's families and people from nearby

villages in Refinery and Pipeline sites. Provisioning for free spectacles for those

with poor eye sight.

Immunization camps being organized with the help of Health Department for

labourer's children and pregnant women at Refinery site.

Supporting running of De-addiction centre – Bathinda, managed by Red Cross

Society of India, through financial contribution. Material donations for furnishing

provided to de- addiction centre – Mansa.

4

Weekly OPDs and routine check-up of labourers at Refinery and their family

members.

24 x 7 Working of Health Centre - Doctors, Paramedical Staff and Ambulance

service made available round the clock at Health Centre at Refinery (Ramsara

Gate) and contact nos. of Doctor & Ambulance is displayed in each labour colony.

Providing infrastructure support to local hospitals near the Refinery. For up-

gradation of Government Hospital at village Raman near refinery site, medical

equipment like Computerized ECG Machine, Boyles Apparatus, ventilator, cardiac

monitor etc. and other facilities have been provided.

Awareness camp on HIV aids conducted at Refinery site for drivers with support

of the Punjab Government’s Health Department.

Hygiene

Regular fumigation for pest control, fogging for mosquito control and spraying &

cleaning of garbage being done at labour colonies at Refinery site.

Cleaning of drinking water reservoirs at village Raman near Refinery site.

Community development

RO Plant of 6000 litres/ hour installed for providing RO treated water to labour

colonies near Refinery site.

Installing water coolers in nearby villages of Refinery site.

Aiding schools of nearby villages by providing school bags, pencil boxes, note

books, uniform, shoes etc. Donated furniture to Government Primary school at

Pipeline site, Dhansa.

RO System and Water Coolers installed in five Elementary Schools of different

villages near Refinery for ensuring clean portable water for children.

Supporting various charities and community organizations to make a positive

contribution to the society.

Environment

Trees planted on raw water channel land strip and approach road strip of GGSR

with the support of Forest Department.

Widening and strengthening of roads in the vicinity of refinery done in partnership

with Government of Punjab. Approximately 25 kms of road strengthened and

5

widened via three roads including Talwandi Saboo to Raman road, Raman-

Talwandi road to Kanakwal road and Raman to Ramsara Road.

Care is being taken to ensure minimal disturbance to ground flora including small

shrubs during pipeline laying activity.

Committed to help in regeneration of vegetation and stabilization of disturbed

sand dunes and wherever possible to restore the plantation damaged during

pipeline construction by re-plantation/vegetation of local special breeds.

Guru Gobind Singh Refinery HMEL operates the 9 MMTPA Guru Gobind Singh Refinery located at Bathinda. The

state-of-the-art refinery is a zero bottoms, energy efficient, environment- friendly,

high distillate yielding complex refinery that will be producing clean fuels and

polypropylene by processing heavy, sour and acidic crudes.

Fifth biggest refinery in India. Contributes to increasing refining capacity of India

from 62 million tonnes to 213 million tonnes

With an investment of over $4 billion, it is the largest company in the state of

Punjab in India

This refinery is the single largest investment at any location in Punjab and is the

first Oil and Gas industry in the state

Among the highest yields of propylene, the feedstock for polypropylene, almost

twice that of earlier processes

Plant-floor' to 'Top-floor' Integration to create an 'Instrumented, Interconnected

and Intelligent' enterprise

One of the highest Nelson Complexity Indices in the region with the ability to

process Heavier and Sour crudes

World Class Technologies deployed to maximise efficiency in operations

High Quality products that are geared to meet present and future environment

protection norms

Synergies with HPCL's existing Marketing Network in Northern India

Self-sufficient Captive Power Plant (CPP) with a gross capacity of 165 MW

The refinery incorporates the latest technologies enabling it to excel the current

specifications available in the country. The refinery configuration has been

developed after extensive linear programming, keeping the domestic and regional

6

requirements in mind, the latest cost effective technologies available for generating

required fuel specifications, and future changes. The present configuration translates

into one of the highest Nelson Indexes* for the refinery amongst all the refineries in

the country.

The Refinery has transformed the socio- economic landscape of the region to a large

extent.

The crude is carried upon VLCC (very large crude carrier), which is then carried

onshore to Mundra COT (crude oil terminal) through 48” 17km pipeline SPM (single

point mooring) from where it is transported to bathinda in 28” and 30” diameter 1012

km long pipeline.

Products & Services

'High Ethical Standards’ and ‘Respect for People’ are two of the important Core

Values imbibed at HMEL. HMEL conducts all aspects of its business with a

commitment to integrity, high ethical standards and good Corporate Governance

practices. HMEL Team is committed to maintaining a customer focussed approach in

designing and implementing our business processes, well supported by our Core

Values.

HMEL will produce the following Petroleum & Petrochemical products:-

Liquid Products

The following facilities are being developed at the Refinery to supply the liquid

products:

3 Full-rake Rail Sidings

Road loading facilities for MS, SKO, HSD, Naphtha, MTO, Hexane & ATF

Pipeline transfer of the products to local marketing terminal, HPCL Bathinda

terminal and to Bahadurgarh terminal on HPCL cross country product pipeline.

LPG Transfer to HPCL bottling plant.

All Liquid products will be marketed by the JV partner M/s. Hindustan Petroleum

Corporation Ltd. Any enquiries regarding the Liquid products may be directly

addressed to the respective HPCL Offices.

Liquid Products:  

Motor Spirit (MS), High Spirit Diesel (HSD), Supreme Kerosene Oil (SKO), Aviation

Turbine Fuel (ATF), Liquefied Petroleum Gas (LPG), Mineral Turpentine Oil (MTO),

Naphtha, Hexane.

7

Solid Products: Polypropylene, Pet Coke and Sulphur.

Polypropylene Unit

As part of the Refinery project, HMEL is setting up a Polypropylene Unit (PPU),

utilising Novolen® Gas-phase polypropylene process, with a production capacity of

4,40,000 MT/annum of Homo-Polymer Polypropylene. HMEL shall be producing

entire range of PP Homo-Polymers, to service the demand of customers from all

application segments. HMEL’s PP Unit is integrated with its world class Refinery,

ensuring feedstock safety at all times. In addition to the World class technology,

HMEL is implementing Best industry practices, in all aspects of our businesses. It

are setting up a state of the art R&D and testing facility, to ensure continuous

improvement in our product and to support application development initiatives for

customers. Polypropylene is one of the fastest growing polymers, with worldwide

growth forecast at 5-6% annually in the near foreseeable future. It is expected to

grow at twice the rate of growth of the GDP. 

Higher growth of PP can be attributed to the ability of Polypropylene to replace the

conventional materials (such as paper, wood, glass, metal etc.) and some other

polymers, by demonstrating equal or better properties and at a lower cost. It is the

lightest of the widely used thermoplastics with specific gravity of less than one. It has

no taste or odour and is non-toxic. Polypropylene is the most versatile of all

thermoplastic polymers, with following characteristics:-

Lowest density of all major thermoplastic polymers, which makes it a preferred

material on overall economics, and being light weight.

Excellent chemical resistance for packaging applications such as cosmetics,

medical use, caps and closures.

Good stiffness makes it suitable for applications like furniture, containers and

thin-wall packaging.

High transparency, for high transparency film applications.

Good impact strength makes it suitable for technical applications, such as in

automotive and appliances applications.

Good heat resistance makes it suitable for hot & cold water piping applications.

Low water absorption makes it suitable for hygiene and geo-textile applications.

8

Good moisture barrier makes it suitable for packaging of hygroscopic & food

products.

Good Stretchability for high tenacity fibres, nonwovens and tape yarns, and

biaxally oriented film for flexible packaging, adhesive tape and lamination.

Lummus Novolen Technology GmbH (Novolen) is a leader in polypropylene

technology, with worldwide licensed capacity in excess of 7 million metric tons.

Novolen is a wholly owned subsidiary of Lummus Technology, Germany, a CB&I

Company.

Novolen licenses the Novolen® gas-phase process for the production of

polypropylene resins. This highly flexible process is reliable, versatile and

environmentally friendly.

HMEL is utilising Novolen® gas-phase polypropylene process using Ziegler-Natta

catalysts for the production of a full range of commodity and performance products

that meet the requirements of even the most demanding applications. Novolen’s

unique Versatile Reactor Concept (VRC) utilizes two vertical, mechanically stirred

beds, gas-phase reactors, with which it is possible to achieve the broadest product

capability. Homopolymers can be manufactured either in a single reactor or in

parallel operation of two reactors depending on the requirement. Small reactor

volumes allow rapid grade changes to meet diverse customer requirements.

Special characteristics available through Novolen Technology are:

Bimodal grades for High Line Speed BoPP films

Low melt flow grades for pipes

High Crystalanity Grades

High MFR Controlled Rheology Grades

Exceptional lot-to-lot and within-lot Uniformity.

High Stiffness grade capability

Solvent-free gas-phase process, low fish eyes for film applications

Low odour and taste

High Speed Spinning Application grades

Pet Coke

Petroleum coke (Pet coke) is a carbonaceous solid derived from oil refinery

Delayed Coker Unit.

9

HMEL is in process of setting up a 9 million tonne per annum refinery at Bathinda,

Punjab. In this refinery about 9 lakh tonnes per annum of High Sulphur Pet Coke will

also be generated.

BIS Specifications

BIS specification of pet coke as per IS: 8502-1994 is given below:

Particular Value

Moisture (% mass, max) 8-12

Total Sulphur, % mass, max 4.5-7.5

Ash, % mass, max 0.2-0.3

Volatile Matter, %mass, max 8-11

Fixed Carbon, % mass, min 87.93-91.01

Gross Calorific Value, (GCV) Kcal/kg7,800-8000

Major Characteristics

Petroleum coke is the solid residue remaining after the distillation of petroleum

materials. It is a carbonaceous solid derived from oil refinery Delayed Coker Unit.

High Carbon Content: Its high carbon content makes it an excellent heat energy

source.

High calorific Value: Pet coke has high calorific value, ranging from 7000 to 8500

Kcal/kg, which makes it an economic fuel as compared to the alternate fuel coal.

Low volatile Matter: Low volatile matter makes it a slow burning fuel so it requires

high ignition temperature.

High Sulphur Content: It has high Sulphur content, which necessitates the

deployment of SOx capture or removal system to reduce SO2 emissions. However,

Pet coke is ideal for burning in lime kilns, where the sulphur combines with various

salts of calcium to form sulphates, thus limiting the SO2 emission.

Low Ash Content: Pet coke has extremely low ash content, which eliminates the

need to handle and dispose high quantity of ash associated with combustion of

Indian coal having 15-35% ash.

Hard Grove Index: Pet coke has low Hard Groove Index, which makes it relatively

harder material to grind and pulverise.

10

Comparison of Indian Coal, Imported Coal & Pet coke

A comparison of specification of C grade Indian non-coking coal used by cement

industry, coal imported from Indonesia and pet coke to be produced by HMEL is

shown below

Parameter Average Values

‘C Grade’

Indian Coal

Coal Imported

from Indonesia

Pet coke to be

produced by

HMEL

GCV (Kcal/kg) 4940 6400 8200

Sulphur, (% mass, max) 0.8 1.00 7.5

Ash Content, (% mass, max) 32 4.5 NIL

Volatile Matter, (% mass,

max)27 41 10

Moisture Content (%mass,

max)4 16 10

Metallic Impurities Absent Absent Present (Ni & V)

Non-Metallic Impurity Present Absent Absnt

Hard Grove Index (HGI) - - 30-40

Size in mm (Max.) - - 100

SULPHUR

Introduction 

HMEL is in process of setting up a 9 MMTPA refinery at Bathinda, Punjab. In this

refinery about 2 lakh tonnes per annum of Sulpur will also be generated, in powder

and lumps form. Sulphur is a non-metallic chemical. In its native form, it is a bright

yellow crystalline solid. In nature, it can be found as the pure element and as sulfide

and sulfate minerals. It is an essential element for life and is found in two amino

acids: cysteine and methionine.

BIS Specifications

11

The guidance values of assay and impurities as per BIS Standard IS:6655-1972, are

as below

Characteristics Percentage by Mass

Assay (dry basis) 99

Colour Bright whitish yellow

Ash 0.25

Carbon 0.1 to 1.0

Table 1: Various Refinery Units & Licensors

Table 2: Refining Capacity

12

Units Licensors Brief Description

CDU / VDU/ NSU

EILSeparates valuable Product s / Distillates Like LPG, Naphtha, SKO, AGO, VGO

NHT, CCR, Isomerization [MS Block]

AXENSProduce Treated Naphtha and high octane gasoline components

DHDT AXENS Produce ULSD (Ultra Low Sulphur Diesel)

VGO-HDT AXENS Produce Low Sulphur VGO (feed for FCC)

FCC-PC, PRU & FCC-NSU

Stone & Webster

Produce LPG, Gasoline, LCO

LPG/FG/Naphtha Treaters

EIL Produce On Spec LPG and Naphtha

Delayed Coker Unit

LUMMUS Tech INC.

Converts low value residue into Valuable Products like LPG, naphtha, diesel, and petroleum coke.

Polypropylene Unit

ABB NovoleneCatalytic conversion of Propylene to Polypropylene

Sulphur BlockHRUHGUATF Merox

EIL/ProsernatEILHTAS(for HGU)UOP

- Recovery of sulphur from sour water- Hexane Recovery Unit

- Hydrogen Generation unit- - Sweetening process to remove

Mercaptans & Sulphur for producing ATF

Process Units Capacity MMTPA Licensor

CDU /VDU 9 /5.3 Open Art – EIL

NHT/ ISOM/ CCR Unit 0.94/0.322/0.50 Axens

Diesel Hydrotreater 4.2 Axens

VGO Hydrotreater 3.0 Axens

FCC- PC 2.22 Stone & Webster

Delayed Coker 3.0 Lummus

Hydrogen Generation Unit 2*0.044 HTAS

Sulphur Unit 2*300 TPD Prosernat

Polypropylene Unit 0.44 Novolene

SR LPG /Cracked LPGTreating

0.24/0.096 EIL

Fuel Gas Treating 0.46 Open Art – EIL

ATF Merox 0.5 UOP

Hexane Recovery Unit 0.02 EIL

Sour Water Stripping I & II 2.35/0.832 Open Art – EIL

Amine Regeneration I & II 2.7/2.7 Open Art – EIL

Utilities & Offsite facilities Open Art – EIL

13

Figure 2: GURU GOBIND SINGH REFINERY CONFIGURATION

14

Fluidised Catalytic Cracking Petrochemical Complex The first catalytic cracker was built in 1936 in U.S.A by Houdry. He had fixed a bed

of catalytic pellets made from natural treated clay. The process was batch wise and

a series of reactors were employed. The process has its inherent disadvantages of

being discontinuous and cumbersome and moreover each reactor was subjected to

reducing and oxidizing conditions in quick succession.

The advantages of the continuous process led to the idea of a moving bed of

catalyst. The thermofor and houndriflow catalytic cracking processes followed

wherein the pelleted catalyst was continuously withdrawn from the reactor by a

mechanical conveyor or a gas pressure which carried the catalyst to the regenerator

and brought it back to the reactor by similar means. Heat liberated from the coke

burning was gainfully utilized in heating and cracking the oil feed in the reactor,

however mechanical means employed put a limit on the amount of catalyst that

could be circulated which in turn meant less heat removed from regenerator.

The more radical development was made by Shell, Standard Oil, Kellog, Texas Co.

& UOP in early 1940 who devised a plant in which catalyst used was in form of a

finely divided powder. This type of catalyst could be kept in a fluid state by blowing

air, gas or steam through it and so the name “Fluid Catalytic Cracking Unit”.

Moreover by controlling the particle size of catalyst and velocity of gas, moving

through it a bed can be formed which although in violent agitation has some of the

properties of a static quantity of liquid.

The unit functioning at GGSR is a Deep Catalytic Cracking (DCC) unit, which is FCC

with higher operating Severity & higher lighter Yield.  Heavy fractions of crude oil

which cannot be further distilled to get useful products are subject to cracking to

extract the useful products.It is widely used to convert the high-boiling, high-

molecular weight hydrocarbon fractions of petroleum crude oils to more valuable

gasoline, olefinic gases and other products. Cracking of petroleum hydrocarbons

was originally done by thermal cracking, which has been almost completely replaced

by catalytic cracking because it produces more gasoline with a higher octane rating.

It also produces by-products gases that are more olefinic, and hence more valuable,

than those produced by thermal cracking. The most important by product from

FCCPC is Propylene. FCCPC consists of two units: DCC and PRU. The capacity of

15

FCCPC plant is 2.22 MMTPA and the PRU plant is 0.44 MMTPA. The DCC

technology is provided by SHAW Stone & Webster's and this is the first DCC in

India. FCCPC is the most profitable plant for any refinery today making it an

essential part of the heart of the refinery.

Figure 3: Feed and Products of FCCPC

Figure 4: Position of FCCPC in the Refinery

16

The Converter Section includes,

Reactor/Regenerator System

Main Air Blower and Air Heater System

Flue Gas Handling System

Catalyst Handling System

Figure 5: Flow Chart of the Conversion Section

FEED

The feed for FCCPC is HOT VGO HDT and HCGO from VDU/CDU and DCU and

COLD VGO from the VGO HDT storage tanks. The feed is first preheated in a heat

exchanger before reaching the reactor column. Conradson Carbon Residue (CCR)

indicates the coke forming tendency of the feed. High CCR levels result in higher

regenerator temperatures. We also prefer the feed contain more of paraffins than

aromatics as this increases the difficulty of cracking thereby requiring higher reactor

temperatures.

REACTOR COLUMN

The Reactor column consists of two parts: The Riser Column and the Secondary

Column. The Riser column is fitted with six nozzles (3 for LCN, 3 for C4) for the feed

inlet. Inside the riser column the feed comes in contact with the catalyst ZEOLITE

from the Regenerated Catalyst Supply Valve (RCSV) where the reaction happens

very fast. This is an endothermic reaction for which the reactor overhead

17

temperature (ROT) is maintained at 565 oC and 0.8 kg/m2 pressure. There is also an

inlet for MP steam in the reactor column to carry the reactants as well as the

products to the secondary column and atomises the feed. The riser steam also

reduces the hydrogen transfer reaction which would otherwise convert the propylene

to propane and reduce the economic viability of the FCCPC significantly.

As the reaction mixture reaches the secondary column, the catalyst hit the

mushroom bed and falls down into the Spent Catalyst Supply Valve (SCSV) and

flows to the regeneration column. The mushroom bed consists of large number of

molecular sieves to separate the overhead products from the catalyst. The overhead

products go to the cyclone which separates any remaining traces of the catalyst and

the overhead vapour is then sent to the main fractionator.

Primary Cracking Reactions:

Secondary Cracking Reactions

18

CATALYST

The catalyst used is a Silica-Alumina catalyst which is made by exchanging the H+

ion with Sodium, forming a zeolite. In this form the catalyst is somewhat inactive and

by replacing it with a rare earth ion, several tetrahedral can be linked together.

Charge separation occurs on the catalyst and the acid sites (formed by ionization of

H+) are no longer blanketed.

The catalyst consists of a matrix and a zeolite. The matric contains binder, active

alumina, clay and special additives. The binder holds the catalyst together. The

zeolite portion is a molecular sieve with a crystalline silica-alumina in which

aluminium and silicon are tied together by oxygen atoms in a truncated arrangement

called the Sodalite Units.

Figure 6: Schematic Showing the Catalyst in Action

REGENERATION COLUMN

The Regeneration column is where the catalyst activity is regenerated to be used in

the reactor column. The spent catalyst from the reactor column contains coke,

nitrogen, sulphur as well other impurities which act as catalytic poison. The nitrogen

compounds in the FCC feed also deactivate the catalyst activity resulting in higher

coke and dry gas (fuel gas) make. Inside the regeneration column, the spent catalyst

comes in contact with air from the main air blower (MAB). As soon as it comes in

contact the coke reacts with the oxygen to form CO and CO2. The waste overhead

consisting of CO, CO2, NOx, SOx from is then passed from cyclone and then heated

and treated and used later for steam generation. The Flue gas is sent through a

19

silencer to the stack or can be used to generate some more steam or to power

expansion turbines to compress the regenerator air and generate electric power. The

reaction in the regeneration column is exothermic thereby increasing the increasing

the temperature of the regenerated catalyst to 710 oC. The pressure in the column is

1.12 kg/m2 and consists of 18 cyclone separators. In case the conversion of coke

doesn’t raise the temperature of the catalyst to the desired levels, the slurry recycle

from the main fractionator to the reactor can be used to elevate the heat of the

reaction by providing more coke production.

Figure 7: Schematic Showing the Convertor Section

MAIN FRACTIONATOR

The effluent vapours from the reactor must be condensed and fractionated into the

desired products. The main column performs both of these operations yielding net

gas and un-stabilized gasoline as net-overhead products, light cycle oil (LCO) as net

side cut products. Heavy Cycle Oil (HCO) is also drawn as a side cut and circulated

for heat exchange but no net HCO product is produced. The column is designed to

handle the superheated reactor effluent vapours and large quantity of vapours which

rises through the column.

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Reactor vapours at approximately 500 oC enter the bottom the main column below

the disc and donut trays. The disc and donut trays are used because large vapours

load in the bottom section of the column. The superheated vapours must be cooled

below 365 oC before fractionation can commence. Coke can form in the column

bottoms if the bottom material has too great a residence time at a high bottom

temperature. A quench stream of cooled bottom material returning below the disc

and donut trays is used to keep the bottom temperature below 365 oC cracking

temperature to prevent coking.

Desupersaturated vapour rise from main column bottom into the cooled heavy

cycle oil section. This section contains two valve type trays and an accumulation

tray. The cooled HCO circulating stream, returns through a distributor, condenses

the HCO fraction from rising vapours. The liquid is collected on HCO accumulation

tray from which it is withdrawn for pumped flow controlled circulating heat exchange

streams.

Uncondensed vapours from heavy cycle oil section rise to light cycle oil

section. The cooled cycle oil circulating stream returns through a distributor and

condenses the light cycle oil material from hot rising vapour. The refluxing liquid

collection accumulator LCO tray from where it is withdraw for pumped flow controlled

circulating stream. Liquid from accumulator also flows to the top tray of the light cycle

oil stripper. Stripped vapours return to main column above LCO accumulator tray

and rise with lighter vapours to naphtha section.

The remaining uncondensed gasoline range vapours, light hydrocarbon gases

and water vapour pass through top trays into the overhead system where gasoline

and water are condensed by main column overhead condenser and collected in the

main column overhead receiver. Condensed gasoline is pumped from overhead

receiver on temperature control to top of the main column above tray. This

maintains desired endpoint of final stabilized gasoline product. The gasoline and

separated water are individually pumped on level control. From overhead receiver,

uncondensed light gases flow to Gas Concentration (GASCON) unit on pressure

control.

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Figure 8: Salient Features of Some of the Equipment Employed in FCCPC

GAS CONCENTRATION (GASCON)

The function of the Gas concentration unit is to separate lean gas, stabilized

gasoline and Wet gases obtained from main fractionator overhead drum. The

overhead gases from fractionator reflux drum are sent to Wet gas Compressor. The

gases are compressed in stage 1 and cooled to knock condensate. The condensate

is routed to HP receiver. The compressor gases from stage 1are further compressed

in stage 2 of wet gas compressor. The compressed gases are sent to HP receiver.

The gases from HP receiver are sent to primary absorber where LPG component is

absorbed by un-stabilized naphtha and stabilized naphtha stream. The gases

coming from primary stripper are then sent to sponge absorber where LCO is used

to absorb additional LPG component.

The liquid streams from primary absorber and HP receiver are sent to a

stripper to strip out any fuel gas components. The stripper bottom is sent to

debutanizer column where LPG is recovered as top product and FCC gasoline is

obtained as bottom product.

While LPG is given amine and caustic treatment before sending off-plot, gasoline

is given caustic treatment before routing to storage tanks. Naphtha from Debutanizer

bottom is sent to the Naphtha Splitter, where LCN, MCN and HCN are separated.

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LPG from top of Debutanizer, after caustic treatment is sent to Depropanizer to

separate C3 from C4. C3 from top of Depropanizer (C3- & C3=) is sent to the PRU

section, while C4 is sent as LPG.

Figure 9: Schematic of the MF & Gas Plant

PROPYLENE RECOVERY UNIT (PRU)In this section, there is no chemical reaction involved. The C3 Splitter unit recovers

the polymer grade propylene from the feed by fractionation. The energy requirement

for the fractionation operation is mostly met by integrating the cooling demand in the

MF & Gas with heat requirement in the C3 Splitter reboilers through Hot Water Belt

(HWB) circulation loop. Remaining heat requirement is met by LP steam. The C3

(C3- & C3=) stream from Depropanizer is first sent through Dryer to remove water

and RSH-COS removal bed. These are fixed bed reactors. The C3 stream is then

subjected to fractionation, i.e., the C3 stripper and Rectifier columns. The propane

C3- from Stripper bottom is routed to the LPG product stream. Propylene recovered

is sent to Arsine removal bed and then sent out as product.

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Figure 10: Schematic of the Propylene Recovery Unit (PRU)

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CONCLUSIONFluidised Catalytic Cracking Petroleum Complex is a continuous running unit of Guru

Gobind Singh Refinery (GGSR), Bathinda. In recent years, it has gained importance

due to the production of petrochemical products and their economic demand.

As of 2006, FCC units were in operation at 400 petroleum refineries worldwide and

about one-third of the crude oil refined in those refineries is processed in an FCC to

produce high-octane gasoline and fuel oils. At GGSR, its yearly output is 2.22

MMTPA. The design capabilities being offered by Lummus Technology and Indimax

Technology with continuously improving upon the performance of this unit has made

FCC an increasing competitive piece of technology.

It is still in its adolescent stage of operation at GGSR but the task of continuously

operating it at its maximum capacity is going to benefit HMEL for many more years

to come.

REFERENCES

WEBSITES www.hmel.in http://en.wikipedia.org/wiki/Fluid_catalytic_cracking http://resources.schoolscience.co.uk/Exxonmobil/infobank/4/flash/cracking.htm

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