操作参数对中空纤维NaA分子筛膜渗透汽化性能影响的实验与模拟

Experimental and Simulation Studies of Operation Parameter Effects on Pervaporation of Hollow Fiber Supported NaA Membranes

采用串联传质阻力模型探讨乙醇/水混合组分在中空纤维Na A分子筛膜内的渗透行为,其中混合组分在Na A分子筛膜层的渗透行为采用普遍化Maxwell-Stefan方程进行描述,而混合组分在中空纤维支撑体层的渗透行为则采用努森、黏性流混合扩散模型进行描述。通过该模型考察了进料温度、水含量等操作参数对中空纤维Na A分子筛膜乙醇脱水渗透性能的影响。结果表明,模拟计算结果与实验结果吻合较好,水通量随着温度与进料水含量的增加而增大,而渗透侧压强的影响与之相反。高水含量下水的吸附量趋于饱和使得水通量随水含量的变化较小;渗透侧压强高于1 k Pa时,水组分在膜层与支撑层中间侧压强增加明显。

A series-resistance mass transfer model was used to study pervaporation （PV） permeation of ethanol/water mixtures through hollow fiber supported NaA membranes. The permeation of the mixture through the zeolite membrane layer was described by a generalized Maxwell-Stefan equation, while the permeation of the mixture through the hollow fiber support was described by a combined Knudsen diffusion and viscous flow model. Effects of feed temperature and water content on PV performance were extensively investigated. The results show that the simulation results are in agreement with the experimental results. The water flux increases with the increase of operating temperature and feed water content, but it decreases with the increase of operating pressure at permeate side. The water adsorption on the membrane side is saturated under high feed water contents, which results in little variation of water flux as a function of feed water content. When the permeate pressure is above 1 kPa, water pressure increases notably at the interface between the zeolite and support layers.