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

U-I : 3 MTPA Cement

Commissioned : 1997

U-II : 3.5 MTPA Cement

Commissioned : Jan’2011

PRISM

CEMENT

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,

bnsingh@prismcement.com

• Mr. N. P. Singhai, Jt. G M (E&I), Prism Cement Ltd,

npsinghai@prismcement.com