摘要
通过对比和分析不同温度、不同时间下垃圾填埋场中膜浓缩液蒸发的挥发特性和挥发性有机物的种类,研究了在其蒸发过程中的有机物挥发情况,并基于此设计了直接利用高温烟气先间壁换热再直接换热的一体化蒸发装置,通过对高温烟气温度、浸没深度、蒸发时间的优化,最终实现了烟气热能的高效利用和常压下的减压蒸发效果。结果表明:随着温度的升高,尾气中高沸点、长碳链的挥发性有机物的种类和挥发量增多。挥发性有机物主要为烷烃类,100℃以后,苯系物和醇酯类物质增加明显;温度为80℃,蒸发0.5h和1h,低分子量有机物大量释放,高沸点物质挥发较少;400℃、450℃、500℃、550℃温度下高温烟气蒸发时,液相蒸发温度在85℃左右,与尾气温差保持在5～6℃,传热传质快,且挥发性有机物的种类与直接蒸发结论基本一致,提高了在较低温蒸发状态下热能的高效利用。同时,该尾气经活性炭吸附处理后,剩余挥发性有机物少,效果明显。
By comparing and analyzing the volatilization characteristics and types of volatile organic compounds in the evaporation of membrane concentrate in landfill at different temperatures and time, the volatilization of organic compounds in the evaporation process was studied. An integrated evaporation device, which utilizes the high-temperature flue gas first-wall heat exchange and then direct heat exchange, was designed. Through the optimization of the temperature, immersion depth and evaporation time of the high-temperature flue gas, the efficient use of flue gas thermal energy and the decompression evaporation under normal pressure are finally realized. The results indicated that the species and the concentration of volatile organic compounds with high boiling points and long carbon chains increased with the increase of evaporation temperature. It was noteworthy that the volatile organic compounds were mainly alkanes. When the temperature exceeded 100℃, the concentration of benzene series and alcohol lipids increased significantly. When the temperature was close to 80℃ and the evaporation time was 0.5 h or 1 h, organic compounds with low molecular weight were significantly released, however, the organic compounds with high boiling points existed in few. When the evaporation temperature at 400-550℃, the liquid evaporation temperature reached to 85℃, the difference between liquid evaporation temperature and tail gas temperature is maintained at 5-6 C. Under the above conditions, the heat and mass transfer was fast and the species of volatile organic compounds were basically consistent with the conclusion of direct evaporation. Meanwhile, the utility of heat energy in the evaporation process at lower temperature was enhanced and the volatile organic compounds were effectively removed after being adsorbed on activated carbon.
作者
夏珺
蔡一地
张俊丰
黄妍
XIA Jun;CAI Yidi;ZHANG Junfeng;HUANG Yan(College of Environment and Resources, Xiangtan University, Xiangtan 411105, Hunan, China)
出处
《化工进展》
EI
CAS
CSCD
北大核心
2019年第5期2485-2490,共6页
Chemical Industry and Engineering Progress
基金
湖南省科技重大专项(2015sk1002)
关键词
垃圾渗滤液
膜浓缩液
蒸发
挥发性有机物
反应器
传热
landfill leachate
membrane concentrate
evaporation
VOCs
reactors
heat transfer
