PRISM CEMENT LTD. CEMENT WORKS
MANKAHARI, SATNA
ENERGY EFFICIENCY : A GIZMO
MK JHA
BN SINGH
NP SINGHAI
P R I S M C E M E N T
PRISM CEMENT Energy Conservation
call of Time, World
and
Forthcoming Generations
For Sustainability of Quality Life. Presentation recites success story at Prism Cement Ltd, wherein
turn around at energy front happened due to able guidance and
zeal to excel, without much of investment.
SECTION UNIT-I UNIT-II
Clinkerisation 6000 TPD (Guaranteed) 7200 TPD (Guaranteed)
7200 TPD (Potential) 8000 TPD (Potential)
Cement Grinding 3.0 MTPA (PPC) 3.6 MTPA (PPC)
Plant Capacity
Core Equipment Capacity
SECTION UNIT-I
Lime stone Crusher 1200 TPH
Raw Mills 275 TPH x 2 nos.
Kiln 6000 TPD / 7200 TPD
Coal mill 65 TPH
Cement Mills 180 TPH x 2 nos.
Packers 120 TPH x 6 nos. 240 TPH x 5 nos
275 TPH x 2 nos
74 TPH
7200 TPD / 8000 TPD
300 TPH x 2 nos
750 TPH x 2 nos
UNIT-II
PRISM CEMENT
PRISM CEMENT
PURSUIT TO ENERGY EFFICIENCY
PAT is an activity that encourages conservation through rewards.
We created energy forum to comply with PAT requirements.
Baseline SEC as 783 kCal/kg of equivalent product.
Target SEC as 749 kCal/kg of equivalent product.
Arrived at way forward suiting plant condition, on following Base:
•preventing losses
•adopting innovative methods of operation,
•re-visiting the equipment design & specifications with respect to operational
needs
•modifying the equipment to fit in operation point.
•Process optimisation,
•Intensive monitoring to avoid idling,
•effective use of industrial waste materials,
•alternate sources of cheaper electricity,
•grass-root level involvement through awareness campaigns
PRISM CEMENT
We planned a systematic energy audit arrived at a job list based approach,
as described below:
Sl Job Description
Expected
Saving
kW/Hr.
Achieved
Saving
kW/Hr.
Remarks
JOB LIST FOR UNIT-I
1 Identify the list of under loaded motors ( <
50% loading). 35 37.5
2 Identify the motor having poor power factor. 35 21
3 Study of process fans efficiency and plan for
retrofit 917 110
U-I Cooler ESP
Fan being
changed, rest
planned in
phased manner
during this FY
4 Study for optimisation of bag filters purging
sequence and time 30 15.5
5 Compressor monitoring with CCR 50 65
6 Proposal of bag filter fan VFD in Unit-I 10 12.5
7 VFD requirement in P&V system to control
the fan speed 87 55
8 PID loops optimisation & new PID 40 70
PRISM CEMENT
Sl Job Description
Expected
Saving
kW/Hr.
Achieved
Saving
kW/Hr.
Remarks
9 Cooling tower fan optimisation with temp
control 10 11
10 Idle running of Unit-1 (Crusher -U1) 250 By 2 Shift
operation
under
implementation
11
Scope of power less exhaust fan, LED light &
control switch scheme in plant and building
(U-1)
50 45
12 Power saving of changing booster pump from
37 kW to 18 kW and others saving scope in DG 5 6
13 Solar lighting system for guest house, ADM.
building, CCR and school building. 18 15
14 Welding transformer auto on/off system for
saving the power. 20 22
15 Day light/ optimisation by switching off lights 28 35
16 Water pump VFD required to control the
pressure (U-1 pump house) 20 15
17 Transparent sheet on workshop/DG/BC
galleries 10 8
18 Energy saving in lighting by concept of
separate transformer scheme for lighting 100 23 under evaluation
PRISM CEMENT
Sl Job Description
Expected
Saving
kW/Hr.
Achieved
Saving
kW/Hr.
Remarks
19 Rewind motor efficiency check and
replacement with suitable one. 25 15
20
Concept of permanent magnet in place of
mag. Separator. Potential of saving to be
calculated
75 35 being procured
21 Power saving by providing starvation switch
to prevent idle run in unit 1. 25 27
22 Power saving in exhaust fan by new
interlocking provided in cement mill section 2 5
23 Power saving in cement mill section by
introducing software interlocking for 25 15
24 Optimisation of lighting load in Packing plant
and cement mill unit 1 26.52 74
25
Power saving in crusher area Unit 1 by new
software interlocking provided for aux. drive
running time after stop of HT drive.
40 45
26 Bag House U1 - Power saving scope through
V/F Drive 120
proposal being
finalised
PRISM CEMENT
Sl Job Description
Expected
Saving
kW/Hr.
Achieved
Saving
kW/Hr.
Remarks
JOB LIST FOR UNIT-II
27 Power saving by PID loops optimisation and
implementation in U-II 450 215
28 RABH dust transport through bulker 31 scheme under
implementation
29 Plant lighting optimisation by providing on-off
controls at accessible locations in U-II 27.4 47
30 Bag filter rotary airlock modification to
prevent idle run 2.9 4
31 Cooling tower fan VFD 25 23
32 Air conditioner optimisation in cement mill
and RABH load centres 33.25 35
33 Bag filter fan VFD in crusher 54.9 57
34 Idle run avoiding in crusher aux 285 225
35 Crusher 2 shift operation 200 being planned for
execution
36 Welding machine optimisation 28.2 21
37 Compressors run hour control through DCS 50 45
PRISM CEMENT
Sl Job Description
Expected
Saving
kW/Hr.
Achieved
Saving
kW/Hr.
Remarks
38 Kiln shell cooling fan automation with temp 90 75
39 Energy saving by Solar water Heater in G.
House 30 25
40 Provision of false sealing at RABH L/C 27 25
41 VFD in coal firing blowers in U2 18 21
42 VFD in reverse air fan in RABH SYSTEM 70.93 being procured
Apart from above, described next are few major initiatives, which paved
way for mechanism to reap out the advantages:
PRISM CEMENT
Adopting EnMS ISO 50001 :
One amongst pioneers in Indian cement industry to adopt prestigious
EnMS ISO:50001 system.
It orchestrated entire organisation towards movement.
Structured steps of monitoring and awareness sourced novel ideas for
implementation, which yielded coveted results.
Distribution Transformers Load Rationalisation:
Re-visiting loading pattern on distribution and power transformers of
entire network suggested enough scope for rationalisation.
06 transformers switched off in entire plant, which helped in reducing
losses ~ 35 kWh * 24 = 840 units/day.
Planned schedule to switch on in a month time to avoid any degradation.
PRISM CEMENT
Utilities Load Optimisation:
Re-view of plant area illumination as per Lux level and provision of on-
off switches at accessible points. BC galleries, loading platforms and
desolate equipment areas yielded maximum saving opportunities.
Intense monitoring of compressors' utilisation & run-hours through
DCS, equipment cooling and process water consumption, optimisation of
HVAC with false ceiling provisions, use of VFD in P&V systems.
Daylight utilisation wherever possible, use of transparent sheets in
warehouses and workshops.
LED lights replacing conventional ones for area & offices, Solar lights.
Power less exhaust fans, switching off welding machines when not is
use.
Optimisation of auxiliary power consumption in DG House.
PRISM CEMENT
69
7,7
01
50
8,3
05
55
5,5
28
46
5,8
37
0
100000
200000
300000
400000
500000
600000
700000
800000
Jan-15 Feb-15 Mar-15 Apr-15
Utilities Consumption (kWh)
Improvement due to actions taken in utilities consumption:
PRISM CEMENT Opportunity in Motors Efficiency:
Identification of under loaded motors and arranging suitable
replacement from available stock. Benefit ~ 37.5 kW.
Replacement of Cooler ESP Fan SRIM motor (SPRS driven, limitation
of operation above 70% rpm) with DC motor, which helped operation
of fan below 50% rpm as per process requirement.
Power factor improvement at motors' side.
Process Optimisation:
Plenty of scope was identified and worked out at different fronts for
process optimisation to reduce specific power consumption. These are
mentioned in above list.
Resulted reduction in Sp. Power Consumption ~ 1.5 kWh/T of cement.
PRISM CEMENT
Time of Day Tariff (TOD) Utilisation:
As per applicable MPERC tariff structure
Peak hour surcharge - 5% surcharge Off peak rebate - 15% rebate
Stopping equipment during peak hour and maximizing
equipment run during off- peak hours results in reduced bills.
Calculations and experience indicate ~ 03-04 paisa/kWh on total
day wise energy bills reduction, if plant operational requirement
is met with production plan.
Implemented the practice with participation of cross functional
team. SOP prepared and circulated to all for awareness and
controls.
Actual monetary benefit ranges ~ Rs. 9 to 10 lac/month,
depending upon capacity utilisation of plant.
PRISM CEMENT
Month Savings due to TOD tariff
utilisation (Rs.)
Remarks
January 3,53,592 Experiment started
February 10,54,302
March 11,05,545
April 5,04,841 One plant under shut
down
Plan reduced MD of U-II to ~36 MVA from 40 MVA, and for U-I
28.9 MVA from 32 MVA.
Also helped to improve predictive maintenance and improve upon
MTBF and MTTR.
RESULT
PRISM CEMENT
Staggered Run of Equipment to Reduce Maximum Demand:
Improvement in MTBF/MTTR helped to improve Overall
Equipment Efficiency (OEE).
This improvement invoked thought of staggered run of equipment
as production requirement were now being met by even reduced run
factor.
Analysis of the process capabilities w.r.t. required production plan
allowed staggered running of all sections except Kiln.
PRISM CEMENT
Contract Demand Reduction:
Staggered run of sections, TOD tariff utilisation tends to reduce overall
LF, which can affect unit rate, unless MD and CD of plant are in tandem.
Energy efficiency measures, coupled with equipment efficiency
improvement and process optimisation, created opportunity to reduce the
Contract Demand (CD) of both Units.
In U-I we could restrict the Contract Demand from 32 to 30 MVA and
in U-II it was done from 40 MVA to 37 MVA.
Reducing the CD not only improves upon Load Factor, but
also has impact on the fixed cost, demand side reduction on
load and overall GHG emissions.
PRISM CEMENT
31.0
30.1
29.4
29.8
28.5
29
29.5
30
30.5
31
31.5
Jan-15 Feb-15 Mar-15 Apr-15
U-I : Max Demand MVA
40.8 40.16 39.6
19.61
11.24
20.37 20.36
31.51 30.79 32.46
31.41
34.18 34.18 31.84 31.63
28.97 28.12 30.03 30.71
33.97 33.97 34.512 33.38 33.14
31.92
29.27
26.44
30.72
33.96 33.2 34.14
31.53
0
5
10
15
20
25
30
35
40
45
Maximum Demand
PLANT
SHUTDOWN
U-II : Max Demand (MVA)
PRISM CEMENT Optimisation of shutdown power:
- Switched OFF 7 Nos of Distribution transformers out of 10
and one Power transformer out of 02.
- Compressors running reduced by on demand run, as
compressed air required for Girth Gear Lubrication system of
Kiln Aux. only while brick lining.
- Bag House fan power reduced by lowering the minimum
speed limit from 110 to 50 RPM for shutdown period.
- RABH dust transport circuit switched OFF immediately after
plant shutdown.
- PA Fan switched OFF and smaller size Emergency air fan
taken into operation for cooling.
PRISM CEMENT
POST IMPLEMENTATION - RESULTS
Measures taken showed up astonishing results. Few of them:
- Clinkerisation power ~ 48 kWh/t of clinker,
frequently touches even 45.5 kWh/t.
- Cement grinding power ~ 24.2 kWh/t of cement,
often comes as even 21.5 kWh/t.
- Sp. Power Consumption ~ 63.5 kWh/t of cement,
comes as low as 55.4 kWh/t of cement.
PRISM CEMENT
PAT SUCCESS
BEE had given a tough target to achieve w.r.t. baseline study
for PAT Cycle-I.
Apparently extremely difficult to achieve the target, as
projects, which PCL had intended & declared for execution,
failed to realise due to unexpected failures & constraints.
Estimated penalty due to non-achievement was looming
around Rs. 15 crore.
PRISM CEMENT
Implemented measures suggest issuance of E-Certs equivalent to ~ Rs 4cr.
instead of penalty ~ Rs. 15 cr ! Data submitted to BEE for review.
This turn around happened for out of box measures implementation.
783
749
737
710
720
730
740
750
760
770
780
790
Baseline Target Achieved
SEC : kCal/kg of equivalent product
PCL marched ahead with above explained energy saving measures
and firm determination. Turnaround happened!
Appointed Accredited Empanelled Energy Auditor TERI conducted
M&V audit during May'15 and came up with following results:
PRISM CEMENT
FORTHCOMING MEASURES
- Process Fans Retrofitting: Study indicates that scope of ~ 900 kW
saving is there with payback of < 1 year.
-Small Projects on Process Optimisation: Areas have been identified
for further load reduction to the tune of ~ 1.3 MW (both Units
combined). These are under implementation & observation stage.
-Cheaper Power purchase through Open Access: In quest of cheaper
power, we have applied to our discom for allowing us power purchase
through Open Access mechanism. Through IEX we can get cheaper
power as & when available. Other feasibility of group captive mode is
under evaluation, which may benefit us intensively.
PRISM CEMENT
FORTHCOMING MEASURES
-Power generation from Waste Heat Recovery System: Plant has
potential to generate power ~ 14 MW through WHRS. It is under
evaluation and expect to implement in coming FY.
-Unit -I Clinker Cooler Upgradation: Upgradation of U-I clinker
cooler has not only potential to save ~ 2 kWh/T of clinker, but also can
result benefit of ~25 kCal/kg of clinker. It is under evaluation for
implementation.
PRISM CEMENT
WRAP UP
Effective guidance and will full execution reaped out the
benefits!
Coming out of blues, once again PCL is on the path of being
NUMERO UNO of Indian Cement Industry, in all respects.
With implemented measures, continuous monitoring &
analysis, corrections to meet desired results and forthcoming
projects, we are sure to achieve < 55 kWh/t of cement on
consistent basis.
Truly said...
" One Unit Saved = Two Units Generated".
THANKS
For further information, please contact:
• Mr. B N Singh, Sr. G M (Tech), Prism Cement Ltd,
• Mr. N. P. Singhai, Jt. G M (E&I), Prism Cement Ltd,