冷凝换热与协同脱硫性能实验分析

Experimental analysis of condensation heat transfer and synergistic desulfurization

锅炉排烟中含有大量水蒸气,直接排放不仅会造成资源和能源的浪费,还会形成白烟,造成视觉污染和局部雾霾,采用凝结换热技术可有效回收排烟余热,并协同脱除部分污染物。本文设计并搭建了天然气燃烧热态实验台,对烟气横向冲刷水平光管的凝结传热特性展开实验研究,分析对比了过量空气系数、给水温度对凝结换热强弱的影响,拟合出2205不锈钢/PTFE两种换热器的水蒸气冷凝率量纲为1准则关联式。此外,基于搭建的SO_(3)/H_(2)SO_(4)雾化蒸发冷凝实验系统,进一步研究分析了不同工况下烟气中SO_(3)/H_(2)SO_(4)的冷凝脱除规律。实验结果表明,2205冷凝换热器冷凝率为19.53%~85.57%,最大凝结换热系数为250.68W/(m^(2)·K);氟塑料冷凝换热器冷凝率为4.92%~42.04%,最大凝结换热系数为131.09W/(m^(2)·K)。同时,SO_(3)/H_(2)SO_(4)气体冷凝脱除率随着给水温度的升高而增大,随着SO_(3)/H_(2)SO_(4)气体浓度的增大而减小,但一定时间内的H_(2)SO_(4)绝对冷凝量在增加,SO_(3)/H_(2)SO_(4)最大冷凝脱除率达到18%以上。

Exhaust from oil-fired and gas-fired boilers contains a large amount of water vapor,and direct emissions will not only result in the waste of resources and energy,but also the formation of white smoke,causing visual pollution and partial haze.Condensation heat transfer technology can effectively recover the waste heat of the exhaust gas and synergistically remove some pollutants.A hot-state experiment for natural gas combustion was designed.It was built to research on the characteristics of condensation heat transfer and decontamination for two heat exchangers with horizontal tubes.The influence of the excess air coefficient and the feed water temperature on the condensation heat transfer was analyzed,and two non dimensional correlation formulae for the water vapor condensation ratio of 2205 stainless steel/PTFE heat exchangers were fitted.In addition,based on the established SO_(3)/H_(2)SO_(4)atomization evaporation experimental system,the condensation removal rule of SO_(3)/H_(2)SO_(4)under different working conditions was further analyzed.The results showed that the condensation rate of 2205 heat exchanger was 19.53%-85.57%,and the maximum condensation heat transfer coefficient was 250.68W/(m^(2)·K).The condensation rate of fluorine plastic heat exchanger was 4.92%-42.04%,and the maximum condensation heat transfer coefficient was 131.09W/(m^(2)·K).At the same time,the condensation removal rate of SO_(3)/H_(2)SO_(4)increased with the increase of the water supply temperature,and decreased with the increase of the concentration of SO_(3)/H_(2)SO_(4).However,the absolute condensation amount of H_(2)SO_(4)increased within a certain period of time,and the maximum condensation removal rate of SO_(3)/H_(2)SO_(4)reached more than 18%.