Cement Energy and Environment

ENERGY CONSERVATION AT SHRIRAM CEMENT WORKS Introduction S hriram Cement Works (SCW), established in the year 1987, is situated at Kota, Rajasthan. It is a wet process plant of 680 TPD capacity commjssioned for converting hydrated lime sludge Ca(OH) 2 into cement. The lime sludge is a residual product generated by the calci um carbide plant at its sister concem Shri ram Fertilisers & Chemicals, Kota. Envirorunentally sound disposal and management of the lime sludge posed a challenge. This challenge was converted inLo an opportunity through conversion of the waste into a useful product like cement even though the process is less energy effi cient. Besides the twin objective of preventi ng pollution and co nserving natural resources , SCW was committed to reducing the cost of production. Since energy accounts for approx imately 60 per cent of the total direct cost of cement production, the plant directed its efforts on energy reduction. \lultipronged approach Through a multipronged methodology comprising a series of well planned modifications, strict monitoring/control and education of the employees at aUlevels, SCW has achieved impressive gains in energy efficiency over the past few years. A ce ll for measuring and monitoring performance of equipment is in operation. Through periodic interaction wit h the various departments, it identifi es areas for improvement and helps imp lement the necessa ry ameliorative measures. The present article highlights the modifications made and the measures adopted with their respective contribution to energy reduction. Tables I and 2 respectively ummarise the savings achieved in electrical and thermal energy consumption. The decli ning trends in power and coal consumption from 199 1-92 are depicted respectively in Figures I and 2. Table 1 Department-wise saving in electrical energy consumption S.No. Modification/measure introduced Raw Mill and Raw Materials Handling Area I. Closed circuiting of raw mill by installing DSM screens II. Conversion of 3-chamber mill to 2-chamber mill iii. Installation of tertiary cmsher for reducing input size of limestone to raw mill and optimisation of grinding media charge iv. Replacement of DSM slurry pumps by gravity flow V. Modification in structure of slurry mixers vi. Installation of soft starters on reclaimer and stacker VII. Use of slurry thinner to improve flowability of slurry 4 Approx. reduction in specific power consumption kWh/ton of cement 2.0 3.0 0.2 0.2 - 3.0 Remarks Raw mill throughput increased from 43TPH in 1991-92 to 60 TPH in L998-99 as a result of these modifications and close monitoring of mill performance