气液交叉流变温变湿脱除工业废气PM_(2.5)

Industrial Waste Gas PM_(2.5) Removal by Variable Temperature and Humidity of Gas-Liquid Cross-Flow Array

利用工业废气与废水之间的传热传质推动力,构建以扩散泳机理为主脱除PM_(2.5)的气液交叉流阵列(GLCA)。废水在重力作用下分布到垂直布置的导流线阵列表面形成降膜流动液柱群,含尘含湿废气横掠液膜柱群传热传质,带动PM_(2.5)朝水蒸气冷凝的气液界面定向移动(扩散泳),从而使每个液膜柱均成为独立的颗粒脱除单元。建模并求解得到单元效率计算方法,逐排计算GLCA随温湿度变化而变的单元效率,从而建立GLCA液膜柱群颗粒脱除累积效率模型。24 (列)×100 (排)交叉流阵列实验结果表明实验值与模型预测值较为吻合,揭示了GLCA气液传质推动力是PM_(2.5)脱除效率的控制性因素。据此设计了变温变湿GLCA串联组合,利用废热源使废气周期性升温增湿恢复传质推动力,提高脱除PM_(2.5)总效率。模型结果表明:饱和废气温度60℃、气体Re数为72. 6条件下,经过总排数1160的变温变湿GLCA串联组合,PM_(2.5)脱除效率可达90%以上。

Using the heat and mass transfer driving force between industrial waste gas and wastewater,the gas-liquid cross-flow array( GLCA) focuses on diffusiophoresis mechanism to remove PM_(2. 5). The wastewater is distributed by gravity to the surface of the vertically arranged flow guiding array to form a falling film flowing liquid column group. The dusty and wet exhaust gas crosses the liquid film column group to transfer heat and mass,and drives PM_(2. 5) directional movement( diffusiophoresis) towards the gas-liquid interface where water vapor condenses,thus making each liquid film column become an independent particle removal unit. The calculation method of unit efficiency is obtained by modeling and solving,and the unit efficiency of GLCA changing with temperature and humidity is calculated row by row,and the cumulative efficiency model of GLCA liquid film column group particle removal is established. The results of 24( column) × 100( row) cross-flow array experiments show that the experimental values are in good agreement with the predicted values of the model,revealing that the GLCA gas-liquid mass transfer driving force is the controlling factor of PM_(2. 5) removal efficiency. According to this,the series combination of variable temperature and humidity GLCA array is designed. The waste heat source is used to periodically heat up and humidify the exhaust gas to restore the mass transfer driving force and improve the total efficiency of removing PM_(2. 5). The model results show that under the condition of saturated exhaust gas temperature of 60 °C and gas Re number of 72. 6, after the series combination of variable temperature and humidity GLCA array with a total number of rows of1160,the removal efficiency of PM_(2. 5) can reach more than 90%.