热耦合渗透蒸馏分离酸洗废水中HCl的传质研究

采用膜蒸馏分离废水中的HCl时常伴生着水蒸气的传质,影响HCl的分离效果。为抑制水的传质,文章考虑采用热耦合渗透蒸馏,建立了利用实验结果计算总传质系数和选择性分离系数的方程,分析了HCl-H2O体系气液平衡关系及跨膜传质推动力。研究结果表明,升高料液温度或增大料液流速均能提高HCl的总传质系数,但却降低了选择性分离系数;废水为盐酸和硫酸混合液时,能够抑制水蒸气的传质,且硫酸浓度越大,抑制作用越明显,能够同时提高总传质系数和选择性分离系数;废水中含有氯盐时,同离子效应和离子的水化作用产生的盐析效应能够抑制水蒸气的传质,提高选择性分离系数。

Separating HCl by Membrane Distillation and Osmotic Distillation in Acid-washing Wastewater

When HCl is separated from wastewater by method of membrane distillation,it is always accompanied with the mass transfer of H2O,which affect the separation effect of HCl.In order to inhibit the mass transfer of H2O,coupled membrane distillation and osmotic distillation was taken into account,and the equation of total mass transfer coefficient and selectivity coefficient calculated by the experimental results was established,gas-liquid balance relationship and mass transfer driving force in HCl-H2O system were analyzed.Results indicated that total mass transfer coefficient of HCl could increase by rising the feed temperature or velocity,but lowered the selectivity coefficient.When wastewater contained HCl coupled with H2SO4,mass transfer of H2O could be inhibited,and higher concentration of H2SO4 was,more obvious inhibitory action had,and could also increase total transfer coefficient and selectivity coefficient.When wastewater contained chloride,common-ion effect and salting-out effect derived from hydration-ion can inhibit the mass transfer of H2O and enhance the selectivity coefficient.