Cement Plant Cogeneration Opportunities

Rapid escalation of energy costs during the seventies requires a serious investigation of ways to reduce the industrial energy bill which has more than doubled in many states since 1977. Cogeneration offers one way of improving the efficiency of energy utilization for the cement industry. During the forties and fifties, it was common practice in the cement industry to recover the waste heat from kilns to generate electric power. With the advent of central power plants and availability of cheaper power, most of these units were phased out. The energy costs, however, have escalated considerably in the past decade and are now subject to uncertainty with respect to future price and supply. Several engineering studies aimed at evaluating the technical and economic feasibility of cogeneration for cement plants in California were recently conducted. Both steam and organic rankine cycle concepts were considered. The capital requirements and operating and maintenance cost were estimated, and discounted cash flow analyses were performed to determine potential project feasibility. The results of these studies are presented, and cogeneration opportunities are discussed. A discussion of the operating experience at an existing cement plant cogeneration project is also included.