以电厂循环水为热泵低温热源的联产供热系统的冷端优化

Optimization of Cold End System of CHP with WSHP Using Circulating Water of Power Plant

以电厂循环水为热泵低温热源的热电联产供热系统是利用以电为动力的压缩式热泵或者以抽汽驱动的吸收式热泵从电厂循环水中吸热,供热热量主要来自于循环水,其冷端调节同时影响发电收益和供热收益。以采用压缩式热泵的供热系统获得最大经济净收益为目标,对这种联产供热方式的冷端系统进行了研究,分析了冷端调节对系统收益的影响,建立了各个环节的数学模型并提出了求解算法。最后以某600MW机组和热泵组成的联产供热系统为研究对象,应用建立的数学模型对200万到800万m2之间的4个供热面积分别进行了计算,得出最佳入口温度持续增大,最佳循环倍率随着供热面积的增加先增大后减小直到调节范围的最小值,且冷端系统参数取最优时,系统的总收益总是小于热泵收益,实际运行时要在保证凝汽器真空不小于最低值的前提下,尽量选择接近理论最优值的循环倍率和入口温度。

The CHP heating system,which takes the power plant circulating water as the low temperature heat source of heat pump,makes use of the compressing heat pump with electricity-driven or absorbing heat pump with absorption steam to absorb energy from the circulating water.The electrical and thermal income will be impacted simultaneously by the adjustment of cold end.In the view of maximum economic net income,the cold end system optimization is conducted for this CHP system.The mathematical model for every segment of the system are established and solved.At last,based on a certain 600MW unit and compressing heat pump,the system optimization for four heating area between 2,000,000 to 8,000,000 square meter is carried on.It＇s concluded that the best inlet temperature always rise,the calculation ratio increase firstly and decrease to the minimum and the best overall income is less than the heat pump income.In the practical operation,the best parameters should be most closed to the theoretical optimum under the situation that the condenser vacuum is not less than the minimum value.