利用烟气多段换热和烟-水直接接触换热技术,开发适用于天然气燃气装置的低品位烟气余热回收系统,并设计了一套全凝烟气余热驱动吸收式热泵系统。通过能流分析和变设计工况分析,对系统进行工艺流程及设计参数的优化和夹点分析优化。结果表明,优化后系统的COP和供热水温度均高于一般单效吸收式热泵系统,尤其燃气-蒸汽联合循环余热锅炉的烟气余热回收,实现热电联产,供热成本低于一般的燃气供热电站。但实际应用中,驱动热源的热能不足的问题尚未得到有效解决,通过分析热泵节能运行模型特点,并联运行吸收热泵能提高系统整体性能,而采用电能和热能互补驱动的热功复合驱动热泵,有望解决系统驱动热源不足的问题。

A low-grade flue gas waste heat recovery system suitable for natural gas plant was developed by using the technology of flue gas multi-stage heat exchange and smok-water direct contact heat exchange, and a fully condensing flue gas waste heat driven absorption heat pump system was designed. Through energy flow analysis and variable design condition analysis, the process flow, design parameters and pinch point analysis of the system are optimized. The results show that the COP and available hot water temperature of the optimized design parameters are higher than that of the general single-effect absorption heat pump system, and the recovery rate of COP and flue gas waste heat is increased by 7.9% and 14.3%, respectively. The optimum recovery rate of solution heat exchanger is about 82%. Among them, the flue gas waste heat recovery of gas-steam combined cycle waste heat boiler can realize cogeneration, and the heating cost is lower than that of ordinary gas heating power stations. However, in practical applications, the problem of insufficient heat energy of the driving heat source has not been effectively solved. Through analyzing the characteristics of the energy-saving operation model of the heat pump, the results show that the parallel operation of the absorption heat pump can improve the overall performance of the system, and the use of electric energy and thermal energy complementary drive heat pump is expected to solve the problem of insufficient driving heat source of the system.