Reducing energy consumption of a raw mill in cement industry

Abstract

Several grinding methods are available in cement industry depending upon the material to be ground. In cement production process, about 26% of the total electrical power is used in grinding the raw materials. During grinding process, the energy obtained from the rotary burner is consumed. In this study, the first and second law analysis of a raw mill is performed and certain measures are implemented in an existing raw mill in a cement factory in order to reduce the amount of energy consumption in grinding process. The first and second law efficiencies of the raw mill are determined to be 61.5% and 16.4%, respectively. The effects of ambient air temperature and moisture content of raw materials on the performance of the raw mill are investigated. The data collected over a 12-month period indicate that first and second law efficiencies of the raw mill increase as the ambient temperature increase and the moisture content of the raw materials decrease. The specific energy consumption for farine production is determined to be 24.75 kWh/ton farine. The use of an external hot gas supply provides 6.7% reduction in energy consumption corresponding to a saving of 1.66 kWh per ton of farine production.