利用低温烟气余热的吸收-压缩复合热泵系统  

Absorption-compression Heat Pump System for Recovering Heat in Low-temperature Flue Gas

作　　者：姜迎春[1,2] 韩巍[1,2] 

机构地区：[1]中国科学院工程热物理研究所,北京100190 [2]中国科学院大学,北京100049

出　　处：《工程热物理学报》2017年第6期1150-1156,共7页Journal of Engineering Thermophysics

基　　金：国家自然科学基金(No.51576191);国家重点基础研究发展计划(973)(No.2013CB228302)

摘　　要：针对工业过程中大量低温烟气直接排放带来的能源浪费和热污染问题,本文提出一种吸收-压缩复合热泵系统,回收200℃以下的低温烟气余热,制备0.5 MPa工艺蒸汽。该系统将热压缩和机械压缩有机结合,利用烟气高温段余热驱动热压缩过程,替代了部分机械压缩耗功,烟气低温段余热用于氨液在蒸发器的气化,氨气在吸收器中被稀氨水吸收,放出的热量用于生产工艺蒸汽。建立了系统热力学模型,模拟了系统设计工况的热力性能,每100 kW低温烟气,仅需耗电4.81 kW,便可制得25.33 kW高温热量(高于152℃)。进一步研究了发生压力、浓溶液质量分数,精馏塔塔顶温度对系统性能的影响,为系统热力性能优化提供了理论依据。本研究为利用低温工业余热制备工艺蒸汽提供了一种新方法。Since large amount of low-temperature flue gas is rejected to environment in industry, there is strong need to reduce thermal pollution and increase energy efficiency. This paper proposed an absorption-compression heat pump system to recover sensible heat of exhausted flue gas with temperature below 200℃, and produce process steam at 0.5 MPa. This system combines thermal compression and mechanical compression. The high-temperature portion of heat drives the thermal compression process, which can achieve high pressure ratio with lower power consumption by substi- tuting electricity with heat. The low-temperature portion of heat is used to evaporate liquid ammonia and the ammonia vapor is absorbed by the weak ammonia-water solution to release high-temperature heat and generate steam. The system model was developed and the thermodynamic performance was also evaluated. When 4.81 kW of power and 100 kW of heat were input the system, the system can produce 25.33 kW of high-temperature heat at 152℃. Moreover, parametric analysis was conducted, focusing on the generation pressure, the concentration of ammonia-water solution and the vapor temperature at the outlet of rectifier, which will provide theory support for the optimization system performance. This work may provide a new approach to recover low-temperature surplus heat to generate process steam.

关 键 词：热泵 低温烟气 吸收-压缩式热泵 热力学分析 

分 类 号：TK123[动力工程及工程热物理—工程热物理]