BEST PRACTICES TOWARDS ENERGY

EFFECIENCY

UltraTech Cement Limited.

(Unit -Kotputli Cement Works)

Best Practices towards Energy

Efficiency

1. Selected Vertical Mills installed at Raw Mill, Cement Mills & Coal mill

instead of Ball Mills, looking to energy efficiency. 2. Selected High recuperation Efficiency Hydraulic Cooler instead of

Mechanical Cooler, which is having 72% Efficiency, whereas Mechanical Cooler is having 60-65%.

3. Adopted High Efficient Screw Compressor instead of reciprocating compressor.

4. Adopted CFBC boiler even at small capacity of 2X102TPH because of its efficiency compared to AFBC boiler i.e. (having efficiency of 85% instead of AFBC boiler efficiency 81-82%).

5. All Major Process Fans are with Medium Voltage 6.6KV, 36 Pulse VFD (8 No’s).

6. All other Cooler Fans with Low Voltage (690 V) 12 Pulse VFD.

Best Practices towards Energy

Efficiency

7. Having Intelligent MCC (ABB-MNSIS) with the facility of monitoring of power, even for a smallest motor.

8. Adopted intermediate voltage of 690V for motor rating between 200-1000KW to reduce rated current and hence I2r losses.

9. Adopted 11KV instead of 6.6KV medium system which reduced distribution losses at MV system.

10. Started 100% Petcoke Firing in Kiln since Nov’14. 11. Installed 100KWp solar power plant to promote green energy. 12. Replacing conventional lightings with LED lightings in phased manner. 13. Installed movement cum occupancy sensor for reduction of lighting running

hours. 14. TPP bed ash usage in raw mix . 15. Provided baffle plate (guide plate) inside twin cyclone top duct which is going to

down comer duct.

Best Practices towards Energy

Efficiency

16. To reduce the power consumption and increase the mill stability through Cement mills hydraulic line modification.

17. Hydraulic cooler lane DP optimization with cooler lane CPM. 18. Reduction in LOI at Boiler for increasing Boiler efficiency 19. Reduction in Heat rate by inter connection of both TG condensate Lines 20. Smart Air Flow Controller in Air network for Power saving in Compressors

Objective:

Medium Voltage Drives

for all major process fans

Background:

1. Reduction in overall power consumption for cement manufacturing. 2. Constant process parameters for stable operation by close loop speed control.

In cement manufacturing Fuel/power cost is very significant (55-60% of total cost). Hence over all cost can be optimized by optimizing flow and speed of process fans like PH fans, BH fans, Cement Mill Fans etc. Fan power is directly proportional to cube time of its speed, hence by optimizing the speed of drives by close loop speed control with process parameters, a significant amount of power can be saved.

Medium Voltage Drives

for all major process fans

Activities:

Installation of 8 Nos MV Drives in all process Fans since project stage and also controlling the process parameters in close loop auto control of drive speed. Additionally, KCW is also having 690 V Drives for all cooler fans.

Benefits:

• Less power consumption due to wide speed control

• Less maintenance as compare to slip ring motor + SPRS.

• Low Harmonics

• Almost unity Power Factor (Better efficiency of electrical system).

Slip Power Recovery System

for Raw Mill Fans

Raw Mill Fan 2 Nos Motors of 3400 KW each, when run in GRR at between 87% to

90% speed and there are losses of power across the GRR (Around 200 to 250

KW), are recovered through SPRS.

Objective:

HT Bus (Grid)

( (

Feedback Transformer

HT Isolator HT Breaker *

Rotor Resistance

& Starter

Panel*

PWM

Rotor Converter

LRS / GRR

CONTACTOR SPRS

CONTACTOR

M Motor *

(

SPRS

ISOLATOR

PWM

Source Converter

ROTOR

TRANSFORMER

Slip Power Recovery System

for Raw Mill Fans

Installation of SPRS to recover power loss in slip

SPRS will increase in stability of process, as it will operating in close loop and

no effect of change in grid frequency and mill stability will improve

Total power saving approx. 245.3 KW for each fan at 90% operating speed of

fan.

Activities:

Benefits:

Replacement of MH street Lights

by LED lights in Township

• Low Power Consumption (90 W instead of 150W)

• Higher Burning Life (>1,00,000 Hrs in LED and 10,000 Hrs in MH Lamps)

• Low Maintenance Cost.

• Low Start / Restrike Time (almost zero in LED and 2-4 minutes in MH Lamps)

• Lumen Maintenance – at the end of Life LED gives 90% output, whereas in MH Lamps it reduces upto 60%

Benefits:

• 2X102TPH Boilers selected as per load requirement.

• In this range earlier AFBC Boilers were installed in group units.

• CFBC Boilers considered in Place of AFBC because of its higher efficiency as a new technology (having efficiency of 85% instead of AFBC boiler efficiency 81-82%)..

CFBC Boiler for Captive Power Plant

Objective:

100 kwP Solar Power Plant (Colony Side)

Promotion of green energy

Solar Power of 100 KWp Mono crystal type cells (437 cells of 230 Wp) technology supplied by M/s Tata BP Solar Ltd.

Rs. 117.19 Lacs

Approx 1,40,000 KWh/Year to be generated.

Subsidy of Rs. 57 lacs from MNRE (Govt of India)

Objective:

Activities:

Benefits:

Investment:

Power saving in Compressed air system

Power saving in Compressed air by installing compressed air controller.

Rs. 16.59 Lacs

Objective:

Investment:

Movement Sensor at Toilets

High Pressure drop across the top bend portion High sp. power consumption of Preheater fans

Provided baffle plate inside twin cyclone

top duct going to down comer duct

Before After

∆P 45 mmWg ∆P 25 mmWg

Issues:

Provided baffle plate inside twin cyclone

top duct going to down comer duct

Installation of baffle plates (750*800*12 mm) at twin cyclone top duct

which is going to down comer duct.

Four plates in a duct at 90 degree angle.

Fan motor power saved of 681.49 MWh/annum

Annual savings for Rs. 26.0 Lac/annum

Payback time calculated as 0.1 months

Activities:

Benefits:

Hydraulic disturbances due to separate hydraulic system for each roller

To reduce the power consumption,

increase Cement mill stability

through hydraulic line modification

common HSLM

Three separate HSLM

Issues:

Installation of a common HSLM unit for all the 3 master Rollers & soon after this

implementation, pressure deviation became nil between all rollers

Due to Mill stability improvement

Mill output increased by 5 TPH

Mill Vibration reduced from average 7.8 to 5.5mm/sec

Reduce water consumption by average 40KL/day

Total potential saving of Rs123.8 Lac/annum

Power saving of 3240 Mwh/annum

Activities:

Benefits:

To reduce the power consumption,

increase Cement mill stability

through hydraulic line modification

High power drawn by reclaimer harrow drive and Pivot point failure. Load of harrow drive at peak was 70 amp. Material scrapping not proper

Power saving through reclaimer

harrow drive modification

Before After

Issues:

Replacement of spike rods by 150 mm flat leading to uniform extraction of

material.

Load of harrow drive reduced drastically from 70 amps (Peak) to 45 A (Peak)

Annual savings for Rs. 3.7 Lac/annum

Activities:

Benefits:

Power saving through reclaimer

harrow drive modification

Issues: Excess transport air consumption resulting into higher mill sp. Power

consumption

Optimization of air slide blowers

in cement transport

Approach: Interconnection of air blower lines to make common for all blowers delivery 04 nos. of blowers out of 08 stopped under air optimization process

Results : Total 30 kw/hr energy saved resulting into Rs. 12.6 Lac / anum savings Zero investment project

Bag House

To Cement

Silos

Issues:

High pressure drop along excess length of kiln coal conveying line High power drawn by conveying blower due to pressure loss to deliver coal at

firing point

Power saving through kiln coal

conveying line modification

Approach: Conveying line layout changed to reduce 18 mtr. of pipe length Results : Total 09 kw/hr power saved in blower resulting into Rs. 3.6 Lac/anum Payback period calculated as months

Coriolis feeder

160 kw blower

9 mtr.

Ejector line modification at TPP

Opportunity : At the time of Project Ejector motive steam lines were erected as per design with 3 inch dia from PRDS to Ejector for both the Units separately, after commissioning of the plant we were facing problem of Low steam temperature at Ejector inlet i.e. 250 Deg C without de superheating at PRDS while design pressure temperature is 11Ata and 350 Deg C

Approach: A brain storming session has organized with TPP all team members and various suggestions have come. In those suggestions team has taken decision for implementation of one suggestion i.e. 6 Inch dia headed from PRDS to near ejectors then 3 inch line to individual ejectors. New 6 inch header erected and connected with existing PRDS and ejectors Results: •We have got desired temperature i.e. 350 Deg C and also started de superheating. •Ejector efficiency increased and vacuum increases by 0.02 kg/cm2 •Saving of 10 Kcal/kwh achieved i.e. Saving of Rs. 26.30 Lacs/annum

Opportunity:

In Boiler feed Pump we have installed VFD since starting and set point of discharge pressure to VFD is giving manually

Approach:

Looking to the variable load demand One logic made for auto set point to VFD from

Boiler drum pressure.

Results:

Reduction in Power- 40Kwh/day/pump

Saving of Rs. 22.80 Lacs/Annum

Auto set point of BFP with

Drum Pressure - TPP

THE JOURNEY CONTINUES…

UltraTech