Thomas B. Gibbons takes a look at the Conventional Rankine Cycle’s application in the cement sector
>The first major waste heat recovery (WHR) system in a cement plant was the 15 MW unit installed by Kawasaki Heavy Industries for Taiheiyo Cement in 1982. This was a conventional Rankine Cycle using heat from both the kiln and the clinker cooler. As the benefits became generally recognised within the industry, WHR units, the vast majority of which involved the conventional Rankine Cycle, were installed to provide up to about 30% of the power requirements of the plant. The main sources of waste heat were the exhaust from both the preheater and the clinker cooler and, in some of the developing countries where power outages are not unusual, the WHR system may be the only source of reliable power available to the plant operator.
Improvement in the overall efficiency of cement manufacture has resulted in lower exhaust gas temperatures and this development has provided opportunities for alternative technologies, notably the Organic Rankine Cycle (ORC) and the Kalina Cycle, which are more effective in recovering waste heat from lower temperature gases.<
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