一种双级耦合膜法烟气余热回收系统的仿真研究  

Simulation Study of a Two-stage Membrane Coupled Flue Gas Waste Heat Recovery System

作　　者：杨波[1] 袁卫星[1] 侯佳琪 郑天启 YANG Bo;YUAN Weixin;HOU Jiaqi;ZHENG Tianqi(Department of Man-machine-environment Engineering,Beihang University,Beijing 100191,China)

机构地区：[1]北京航空航天大学人机与环境工程系,北京100191

出　　处：《工程热物理学报》2022年第5期1345-1350,共6页Journal of Engineering Thermophysics

基　　金：国家自然科学基金(No.51876002)。

摘　　要：天然气是实现清洁供热的一种有效途径,但目前我国仍面临天然气短缺的问题。因此,通过深度回收天然气燃烧产物—烟气的余热资源以提高天然气热值的利用效率,对于缓解能源紧张问题有着积极意义。本文提出一种双级耦合膜法烟气余热回收系统,利用两个膜全热换热器梯级回收燃气锅炉烟气的全热余热,一方面可以降低燃烧温度,从而减少氮氧化物的排放,另一方面可以提高锅炉排烟湿度,从而为烟气-水膜全热换热器的全热换热提高传质势差,并带动整个系统余热回收能力的提升。本文首先对膜全热传热器的传热传质过程进行数学建模和数值仿真,进而对整个系统进行能效分析。结果显示,系统的全热回收效率最高能达到0.874,而系统的低位热值效率能达到1.090。Natural gas is an effective way to the clean heating. However, the lack of natural gas is still serious in China nowadays. By recovering the flue gas waste heat, the caloric utilization efficiency of natural gas can be improved much, which will help to relieve the energy crisis. This study proposes a two-stage coupled membrane-based flue gas waste heat recovery system, in which two membrane total heat exchangers achieve the cascade heat recovery of the gas boiler exhaust. On one hand, the combustion temperature is lowered and therefore the emission of nitrogen oxides is reduced;on the other hand, with the boiler exhaust humidity elevated, the mass transfer potential difference driving the total heat transfer process of the flue-gas-to-water membrane total heat exchanger is enlarged,as well as the overall recovery capacity of the entire system. This study establishes the mathematic model for the heat and mass transfer of the membrane total heat exchangers, takes the numerical simulation, and conducts the system performance analysis. The simulation results show that the total heat recovery efficiency can reach 0.874 at highest and meanwhile the system efficiency based on net caloric value can reach 1.090.

关 键 词：天然气 烟气 余热回收 膜 全热换热 

分 类 号：TK115[动力工程及工程热物理—热能工程]