Cement and Energy

Efficiency of fans plays a major role in energy conservation. In a typical cement plant, fans consume about 40% of the total electrical energy (Fig.l ). * Main machinery, conveying equipment and auxiliary drive.f. Fig.l Typical power consumption in a cement plant The balance 60% is consumed by mam machinery, conveying equipment and auxiliary drives. A systematic study to identify the low efficiency fans and replace them with a high efficiency fan (efficiency ~ 80%) provides a good potential for energy saving. Under the 'Indo-US Motor Challenge Programme 1996' , Energy Management Centre (EMC) entrusted Holtec Consulting Private Limjted (Holtec) to carry out the ''Showcase demonstration project on energy saving through fan efficiency improvement in cement industry". Under this project, fan efficiency measurements on five major process fans were carried out m two identified cement plants . The details and operating efficiency levels in the fans in one of them are Fan description Raw mill ESP fan Preheater fan Pre calciner fan Cement mill fan Coal mill fan tabulated below: Capacity. of the plant 4500 tpd clinker Type of process Dry Main features of the plant • Raw grinding- Vertical roller mill • Kiln- Five-stage preheater with precalciner • Coal grinding-Vertical roller mill • Cement grinding - Ball mills Installed Absorbed Operating Expected Expected Power Power Fan Power Power Efficiency Saving Saving kW kW % kW kWh/t clinker 5000 3404 66.16 588.89 3.141 1200 686 86.31 0.00 0.000 2400 1679 75.43 95.91 0.5 12 500 380 57.48 106.97 0.571 1200 702 83.41 0.00 0.000 Total Saving 4.224 Double inlet mill gas fan 3