不同温差发电循环流程系统的热经济分析

THERMAL ECONOMIC ANALYSIS OF THERMOELECTRIC GENERATION SYSTEM WITH DIFFERENT CYCLE FLOW

采用模拟的方法,对朗肯循环、卡琳娜循环和上原循环建模,在不同热源温度环境下,分析不同循环流程热效率η和平准化度电成本CLCOE的差异;同时,通过对循环蒸发温度和透平入口压力进行分析,探究其在不同循环流程中对热经济性能的影响。研究结果表明,卡琳娜循环在各热源温度下均有较高的热效率,但经济指标表现不佳;低温热源环境,纯氨工质朗肯循环在同等条件下CLCOE最低,在设计时,朗肯循环应选用饱和蒸汽状态,尽可能增加透平入口压力,减小蒸发过热度;高温热源环境,上原循环CLCOE最低,卡琳娜循环和上原循环CLCOE极小值与热效率极大值对应的透平入口压力存在偏差,按最小CLCOE标准可获得更高的发电量和更低的设备成本。因此,在流程设计时,需考虑不同循环在各热源环境中的热经济性能。

This study utilized simulation method,through the modeling of Rankine cycle,Kalinacycle and Uehara cycle,the differences in thermal efficiency(η)and leveled cost of energy(CLCOE)between different cycle processes were analyzed under different heat source temperature conditions. Meanwhile,the effects of evaporation temperature and turbine inlet pressure on thermal-economic performance in different cycle systems were also explored. The results show that Kalina cycle has highest thermal efficiency in each temperature condition of heat source,but its economic performance is poor. In low temperature heat source,the CLCOEof Rankine cycle with pure ammonia working fluid is the lowest under the same conditions. In design,Rankine cycle should choose saturated steam state,as far as possible to increase the turbine inlet pressure and reduce the evaporation superheat. Instead,in high temperature heat source,the CLCOEof Uehara cycle is the lowest. Moreover,there is a deviation of the turbine inlet pressure corresponding to the minimum CLCOE and the maximum thermal efficiency of Kalina cycle and Uehara cycle. Designed according to the minimum CLCOEprinciple at this point,more power generation and less equipment cost can be obtained. Therefore,thermal-economic performance of different cycles under different heat source temperature conditions should be considered in cycle flow design.