摘要
天然气锅炉排烟温度较高,烟气中含有较多的水蒸气潜热,具有显著的热量回收价值,目前常采用新型工质电动热泵回收天然气烟气余热加热热网回水,助力“双碳”目标的实现。为提升电动热泵的循环性能系数,研究不同工况下新型工质电动热泵适配混合工质的性能,对机组运行中R134a+R245fa,R152a+R245fa,R227ea+R245fa,R134a+R142b,R152a+R142b,R227ea+R142b共6种混合工质的循环性能进行计算分析。针对锅炉房实际运行参数,对比冷凝器热水进出口温度为50/65℃,蒸发器冷水进出口温度为40/35℃及40/30℃工况下各混合工质的热力学性能,得出在该工况下R134a+R245fa(摩尔分数比为0.41∶0.59)为较佳工质。采用所筛选工质对烟气余热回收排烟温度进行优化,分析了不同排烟温度的经济性,对比余热回收收益及电动热泵运行成本,揭示了烟气余热回收最优化温度变化规律,指导余热回收系统设计与应用。
Since the flue gas emitted from natural gas boilers is of high temperature and contains high latent heat of steam,it is worthy to be reused.To pursuit the"dual carbon"target,the waste heat in natural gas boiler flue gas is recovered by electric heat pumps with new working fluids to rise the return water temperature.In order to improve the coefficient of performance of electric heat pumps,their performances under different working conditions are studied.Six types of mixed working fluids,R134a+R245fa,R152a+R245fa,R227ea+R245fa,R134a+R142b,R152a+R142b and R227ea+R142b,show different cycling properties.Under the actual operating condition of a boiler room,the thermodynamic properties of different mixed working fluids are compared when the inlet and outlet hot water temperatures of the condenser are 50/65℃,and the inlet and outlet cold water temperatures of the evaporator are 40/35℃or 40/30℃.The conclusion is that the optimal working fluid under this working condition is the mixture of R134a and R245fa whose mole fractions are 0.41 and 0.59.The benefits of the waste heat recovery system and the costs of the heat pump with the optimized flue gas temperature and selected working fluid are analysed,and the variation law of the economy of waste flue gas recovery with flue gas temperature is obtained.The analysis is beneficial for the future design of waste heat recovery systems.
作者
孙健
秦宇
王寅武
吴可欣
戈志华
SUN Jian;QIN Yu;WANG Yinwu;WU Kexin;GE Zhihua(Institute of Zero Carbon Energy Building Technology,School of Energy,Power and Mechanical Engineering,North China Electric Power University,Beijing 102206,China)
出处
《综合智慧能源》
CAS
2023年第4期19-25,共7页
Integrated Intelligent Energy
基金
国家重点研发计划项目(2019YFE0104900)
国家自然科学基金项目(52090062)
中央高校基本科研业务费专项资金资助项目(2020MS009)。
关键词
“双碳”目标
天然气锅炉
排烟温度
余热回收
电动热泵
混合工质
dual carbon target
natural gas boiler
exhaust gas temperature
waste heat recovery
electric heat pump
mixed working fluid