Relook at energy conservation in Cement Factory

A cement factory is big Energy guzzler. Each component of the processing plant is equally critical. Small reduction in energy consumption can yield big commercial and environmental benefits. Some of the aspects to ponder upon are: Fuel:

Due to frequent variations in the quality of coal, inadequate supplies and transportation bottlenecks go for substitute fuels like, lignite, rice-husk, petroleum coke etc. Use alternate fuels such as natural gas and pet coke. Use industrial and agricultural combustible wastes as supplementary fuel.

Power Supply:

For uninterrupted power supply have your own captive power plant.

Operational Measures:

Use improved insulating bricks/blocks in kiln and preheaters. Rationalise compressed air utilisation. Use energy efficient equipment High efficiency fans Improved Ball Mill internals Carry out Heat and gas balance Recover waste heat of preheater and use for co-generation of power. Increase utilization of waste products generated by other industries(substitution like use of fly ash and petroleum coke, the by-products of thermal power and refinery industry respectively) Install fly ash handling & feeding system. Reduce energy consumption in manufacturing at each stage & monitor energy performance of the plant. Prevent idle running of equipment by providing interlocking arrangement and operating with PLC system. Generate daily report on idle running of equipment, also in terms of monetary losses. Eliminate ingress of false air into the kiln, cooler, coal mill, cement mill and raw mill circuits by plugging leaks. Optimise raw mix Use low ash coal Adopt preventive maintenance approach Repair steam leaks Reinforce heat insulation Establish efficient management information system for identifying various important parameters for efficient operation of the equipment and taking timely remedial measures. Regularly monitor and calibrate flow meters. Minimize waste by installing efficient dust collector equipment. Modify the equipment to recover heat from the preheater and cooler in the process of cement making and effective use of industrial waste. Use exhaust gas from kiln to dry raw material and coal etc. Carry out energy audits. Before improving a process, activities of good housekeeping and equipment improvement should be applied to promote energy conservation. Avoid extra fine grinding of product to prevent wastage of power since it does not enhance long term strength.

Air Compressor:

Reduce compressed air pressure from 8 Kg/Cm2 to 7.0 Kg/Cm2 where ever possible to conserve energy, when required pressure at usage point is 6.0 Kg/Cm2 Stop use of compressed air for floor cleaning. Check for compressed air leakage and arrest it. Switch off one compressor if requirement can be met by balance operating compressors.

DG Sets Operation and Maintenance

Improve SFC of the DG sets DG sets flue gas temperature is more than 4500C install waste heat recovery boilers on DG sets to generate additional power & pre heat fuel oil Improve specific electricity generation by loading in excess of 60% and up to 80%

Motors:

Replace under loaded / overloaded motors with proper size motors. Replace the motors with energy efficiency motors. Prevent idle operation of the motors

Transformer

If possible switch off one transformer running under loaded in parallel. Maintain all transformers at a loading of 70 to 80 % of rated capacity to minimise loss component (no load losses). Try to have separate transformer for lighting where voltage can be kept low.

Power Factor :

Improve power factor by regular checking of current of all the capacitors and their timely replacement. Install Automatic power factor correction device to have power factor of 0.99 to 1.00

Lighting :

Replace 40W Tube light by slim 28W Tube light and electromagnetic choke with electronic choke. Replace 400 Watt Mercury Vapour lamps with 250 Watt sodium vapour lamps or 250 W metal halide lamps. Replace 250 Watt Mercury Vapour lamps with 150 Watt sodium vapour lamps or 150 W metal halide lamps. Provide more transparent sheet instead of asbestos sheets to use natural light. Install energy saver for reducing the lighting load. Prevent unnecessary lighting of the electric lamps. Rationalise lighting in identified areas i.e. remove excess lighting in identified areas. Also relocate lighting, if necessary.