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常压下异丙醇与水形成共沸物,应用精馏法生产工艺能耗较大,本文采用自制的PVA/PVDF复合膜蒸汽渗透分离异丙醇(IPA)-水混合溶液,并应用响应面法确定最优的操作条件。首先,制备了理论交联度为8%的马来酸酐交联的PVA/PVDF复合膜:然后根据Box-Behnken中心组合实验设计原理,以膜的渗透通量和选择性为响应值,操作温度、IPA入膜浓度、膜渗透侧压力3个操作条件为影响因素进行实验:最后对实验结果进行响应面分析,得到了优化的操作条件并通过实验进行验证。综合考虑膜的渗透通量和选择性这2个响应值,求得实验所采用的PVA/PVDF复合膜在蒸汽渗透分离IPA水体系中的最优操作条件是:操作温度为95℃,IPA入膜浓度为82.5 wt.%,膜渗透侧压力为1 kPa,此时的渗透通量和选择性分别达到了1.57 kg/(m~2·h)和38.90。在此最佳操作条件下对模型预测值进行实验验证,膜的渗透通量和选择性的预测值与实验值的相对误差分别为5.7%和9.2%。
Under normal pressure, isopropanol and water form azeotrope. The rectification process consumes a lot of energy. In this paper, the isopropanol (IPA) -water mixed solution is vapor-separated by self-made PVA / PVDF composite membrane. Surface method to determine the optimal operating conditions. First, a crosslinked PVA / PVDF composite membrane with a theoretical crosslinking degree of 8% was prepared. Based on the Box-Behnken central composite experimental design principle, the permeation flux and selectivity of the membrane were used as the response values. The operating temperature , The concentration of IPA into the membrane and the pressure on the permeate side of the membrane were used as the influencing factors. Finally, the response surface analysis of the experimental results was carried out, and the optimized operating conditions were obtained and verified through experiments. Considering the permeation fluxes and selectivity of the membranes, the optimum operating conditions of the PVA / PVDF composite membranes used in the experiment were obtained: the operating temperature was 95 ℃, the concentration of IPA into The membrane concentration was 82.5 wt.% And the membrane permeate side pressure was 1 kPa. The permeate flux and selectivity reached 1.57 kg / (m ~ 2 · h) and 38.90 at this time. Under the optimal operating conditions, the model predictive value was experimentally verified. The relative errors between the permeate flux and selectivity of the membrane and the experimental values were 5.7% and 9.2%, respectively.