Economic Benefit Evaluation of Waste Heat Recovery in Coal-fired CHP System Based on Exergoeconomic Analysis

Abstract As one of the main energy-saving measures and an important part of the power industry, CHP (combined heat and power) has achieved rapid development in recent years, which have the advantages of low heat loss, flexible operation mode, and cascade utilization of energy compared with heating boilers and traditional power plants. However, there is a lack of reasonable evaluation of CHP systems, due to the difference in energy quality of heat and electricity. It is urgent to establish considerable and reasonable evaluation indexes of CHP systems. In addition, in the actual operation of CHP plant, a large amount of waste heat is released into the environment, and there is still room for further improvement in the waste heat utilization. In this paper, an exergoeconomic analysis model of CHP system with circulating fluidized bed boiler is established, and the economic benefits of waste heat recovery in CHP systems are studied. After the application of waste heat recovery, the system exergy efficiency increased from 32.94% to 34.14%. The unit exergoeconomic cost of electricity and process steam did not change much, but the unit exergoeconomic cost of heating decreased by 17.1%, which indicates the economic benefits of waste heat recovery.