中空纤维致密膜基吸收CO2传质过程

研究了硅橡胶/聚砜中空纤维致密膜基吸收CO2的传质机理,考察了吸收剂种类(NaOH,MEA,DEA和TEA)、NaOH浓度、吸收剂流速、吸收剂压力和气相压力对CO2传质通量及传质速率的影响.其中,用2×103mol/m3NaOH作吸收剂时,聚合物膜传质为控制步骤,其传质效率与膜自然渗透相近.

Mass Transfer Process of CO2 Absorption Through Non-porous Hollow Fibre Contactor

A non-porous hollow fiber contactor containing silicone rubber-polysulphone hollow fiber composite membranes is used for the absorption of CO2.The effects of various absorbents,liquid volumetric velocity,liquid pressure,concentration of NaOH solution and gas pressure on the efficiency of CO2 absorption are investigated.The experiment results indicate that the chemical absorption has a higher absorption efficiency than the physical absorption does and the membrane resistance controls the mass transfer accompanied by chemical absorption.Furthermore,when 2×103 mol/m3 NaOH solution is employed as the Absorbent,the overall mass transfer coefficient(5.21×10-6 mol·m-2·s-1·kPa-1) almost reaches the value of permeation without absorption(5.85×10-6 mol·m-2·s-1·kPa-1),and non-porous hollow fiber contactor has a higher selectivity for the existence of liquid film.Finally,the smooth mass transfer process shows that non-porous hollow fiber composite membrane eliminates bubbling and weeping in the liquid phase,which are frequently encountered in microporous hollow fiber contactor.Therefore,non-porous hollow fiber contactor used in this experiment has a potential for using as a gas-liquid contactor.