Cement and Energy

modernisation of one of the kilns was launched, which resulted in a remarkable improvement in the production and productivity of the plant. Despite several inherent constraints like low capacity and highly inefficient equipment compared to present day machinery, several major and minor modific~tions in plant equipment and operating practice have been meticulously planned and are being implemented on a continuous basis to improve conservation of energy utilising the in-house expertise built up over the years. engineered to produce 5 lac tonnes of cement per annum. A massive modernisation programme was launched during 1987-88 to improve the operational efficiency and enhance productivity, with the result the power– consumption-per-tonne-of-cement could be brought down from 143 units/tonne in 1986-87 (before modernisation) to 129 units/tonne over a period of7 years. In addition to this, several major modifications in the plant were also carried out, in house, on a continuous basis from 1993-94 onwards as a result of which the power consumption could be further brought down from 129 units/tonne of cement to 112 units/tonne of cement at the end of 1997- 98. Similarly, the fuel consumption could be brought down from 304 kg/tonne of clinker before modernisation to 195 kg/tonne of clinker at the end of 1997-98. The details of the modernisation carried out and the results achieved are summarised in Table l and depicted in Figure I. These efforts by our team on a continuous basis indeed resulted 111 the plant winning the National Award for best improvement in thermal efficiency for 1994-95. Modernisation and Major Modifications The plant comprising 4 kilns was initially designed and Table 1 Modifications to Plant and their Results S.No. Date Details of modifications Results achieved I. Nov.'87 Modernisation of Kiln - 3 to enhance capacity Reduction in power consumption by from 600 TPD to 1500 TPD by incorporating : 14.00 kWh/t of cement and - Additional stream of 4-stage suspension reduction in beat consumption by preheater with pre- calciner. 177 kcallkg clinker. - Pyrojet burner for fuel efficiency improvement. - Replacement of pneumatic system of transportation by bucket elevators and belt conveyors in raw mill, cement mill and kiln feed system. (Due to the above modernisation, 2 small kilns could be totally stopped). 2. Dec.'94 Installation of one 15 TPH capacity vertical coal Reduction in specific consumption mill for coal pulverisation in place of 3 small ball by 13 kWh/tonne of coal i.e. 3.2 mills. kWh/tonne of cement. ' ~ _l. Feb. '95 Installation of higher capacity raw mill in place of Reduction in specific power 2 low capacity raw mills. consumption by 5 kWh/tonne of cement. 4. Dec.' 95 Conversion of one of the low capacity raw mills Reduction in specific consumption into slag drier utilising kiln exit g(lses to Improve by 0.5 kWh/tonne of cement. the efficiency of cement grinding. 5. Oct. '96 Bifurcation of cement mills fot simultaneous Improved efficiency of cement grinding of 43 Grade OPC and portland slag grinding and reduction in specific cement. power consumption by 6.6 kWh/tonne of cement. 6. Jan. ' 97 Commissioning of slip power recovery system in Reduction in specific power both the preheater waste-gas fans. consumption by 1.8 kWh/tonne of cement. 7. Mar. ' 97 Installation of boltless lining for one of the cement Ensured continuous operation of the mills. mill and contributed to reduction in power consumption. 2