Cement Energy and Environment

Correcti w! ft-fea.Hlres Extending the hopper baffles to a level where the collected material itself can prov ide a material seal, to plug the gas fl ow through the hopper, successfully arrested the sneakage. The enhanced utilisation of the ESP and the tota l el imination of gas sneakage through hopper improved the ESP performance. Conclusion The case study reported brings out how the three problems, namely, rapping cyc les, gas distribution and sneakage of gas through hopper were successfully tackled by the plant in consultation with M/s Precipcare, Pune. The fact that poor ESP performance may be due to multiple reasons producing similar results makes the assessment complex . It establishes in particu lar, that ESP performance can be maximised and stack emissions drastical ly brought down through corTective measures worked out after thorough operational audit by experienced ESP experts. Unlike convent ional measures like addition ofcollection area in the fonn of series or parallel precipitator, these necessitate neither major capital investment nor an excessive downtime. • MULTI-PRONGEDENVIRONMENTAL INITIATIVES BYVASAVADATTACEMENT P.K. Goyenka & B.L. Saini, Vasavadatta Cement ABSTRACT D ollmving the series ofmeasures worked out and implemented by Vasavadatta Cement to improve its energy ..I.."" efficiency and environmental performance (Cement, Energy and Environment, April 2000), the current article focusses on the plant's all-round efforts purely on the environmental front. These straddle the whole range -from conventional fugitive dust suppression and noise abatement measures through those of material conservation like utilisation of waste derived fuels, and fly ash - to ecological preservation by large scale t {~!forestation. Together, these measures have impressively enhanced the plant's credentials of environmental friendliness. Introduction Environmental improvement has been a continuing mis sion with Vasavadatta Cement, a mission distinguished by a holistic approach to and a cal ibrated emphasis on the operationa l and the technolog ical aspects, apart from material conservation and ecological balance. The current article gives a brief account of all the measures the plant has devised and implemented with success. Technological Measures Use of wa~·te oil as kiln fuel Waste oil is among the well known waste derived fuels (WDF) used in cement industry, the other ones being used tyres, rubber, paper, paper waste, waste wood, paper sludge, sewage. Besides being a sound waste management in itself, this reduces the consumpti on of non-renewable foss il fuels, such as coal and cuts down C0 2 evolution from the burning ofcoal. The following facts will explain how the cement rotary kiln is technically the best incinerator for such wastes. The combustion process witlr tlte waste fuel- While the fl ash po int of wastes varies from 226°C to 286°C, the material temperature inside the kiln is close to 1500°C and the gas temperature around 2000°C. The rotary ki ln accepts all types of sol id and liquid wastes with heat values between 550 and 8300 kcal/kg. The organic constituents in the wastes are destroyed by the high temperature, the long residence time and the oxidis ing conditions inside the kiln, while the inorganic ones combine with the raw materials partly replacing the latter. In a cement kiln, the combustion gases get intimately mixed with large quantities ofalkaline process material, and the polluting ones are removed by the process material. Nearly 90 ·per cent of S0 2 is thus removed as a result ofwhich hardly I0 per cent ofwhat 5