Waste heat recovery power generation systems for cement production process

Cement production process is highly energy intensive with approximately 3GJ to 4GJ energy consumption per ton of cement produced. Also energy costs are responsible for 25% of total production costs while 75% of primary energy usage is thermal energy. However, the process is characterized by significant amount of heat loss mainly by the flue gases and the air stream used for cooling down the clinker. Waste heat is generated by fuel combustion process or chemical reactions, and then dumped into the environment even though it could still be reused for some useful and economic purposes. Reducing the amount of wasted heat as well as reusing it has been a matter of great concern for the past couple of decades. A heat recovery system could increase the efficiency of the cement plant as well as reducing the amount of CO₂ emissions to the environment and by lowering the temperature of the exhaust gases. This paper is an introduction to Waste Heat Recovery Generation (WHRG) systems, their operations and feasibility for cement production process also a review of four common power generation cycles, steam Rankine cycle, organic Rankine Cycle, Kalina cycle and super critical CO₂ cycle.