两级地源热泵用于天然气调压发电工艺的性能分析

Performance Analysis of Two-stage Ground Source Heat Pump used in Natural Gas Pressure Regulation Power Generation Process

本文提出了一种涡轮与两级地源热泵相耦合的新型天然气调压工艺,通过Matlab构建了系统热力学模型并借助Aspen/plus和实验数据予以验证,分析了降压和预热过程的碳排放核算方法,探究了涡轮膨胀比和热泵压缩比的最优分配策略,并结合实际案例评估了系统的经济性与环保性。结果表明:R123为热泵最优工质;热泵循环由单级升为双级后,新工艺年均(火用)效率为0.43,提升10.88%,加热效率为2.89,提升15.91%,全年净发电量3.67 GW·h,提升11.6%;相比于节流阀调压工艺,新工艺全年减少CO_(2)排放0.24万t,减少预热成本4.7万元,同时产生经济效益146.94万元。

In this paper,a new natural gas pressure regulation process coupled with a turbine and a two stage ground source heat pump was proposed.The thermodynamics model was built by Matlab,and then verified by Aspen/plus and experiment data.The carbon emission accounting method of the depressurization and preheating process was analyzed,and the optimal allocation strategy of turbine expansion ratio and heat pump compression ratio was explored.The economy and environmental protection of the system were evaluated by an actual case.The results show that R123 is the optimal working medium of heat pump;when heat pump cycle upgrades from single stage to two-stage,annual average exergy efficiency of new process is 0.43,increased by 10.88%;heating efficiency is 2.89,increased by 15.91%;annual net power generation is 3.67 GWh,increased by 11.6%;compared with the pressure regulation process of throttle valve,the new process can reduce CO_(2)emission of 2.4 thousand tons,reducing the preheating cost of 47000 yuan,meanwhile generating economic benefits of 1.4694 million yuan.