Thermal analysis for the evaporation concentrating process with high boiling point elevation based exhaust waste heat recovery

Abstract

In order to reduce energy consumption of the solution evaporation concentrating process with high boiling point elevation (BPE), a novel cogeneration system is proposed to integrate the solution evaporation concentrating and power generation processes using the exhaust waste heat as heat source. Through compared with the conventional three-effect and mechanical vapor recompression evaporation processes, influences from the key operation parameters, including the evaporation temperature and BPE of the solution on overall thermal performance of the proposed system have been investigated. The results showed the overall thermal performance of the three schemes became worse with the rise of the BPE, but the proposed cogeneration system showed prominent thermal performance when dealing solutions with high BPE compared to those of the conventional three-effect and MVR evaporating processes. Moreover, through harmonizing the vacuum evaporation concentrating process and net power output, the optimal evaporating temperatures to achieve the maximal energy saving potential are obtained under different BPE working conditions for the proposed cogeneration system.