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T型沸石膜的放大制备及应用研究

发布时间:2019-01-09 11:44
【摘要】:渗透蒸发是一种高效节能的膜分离技术,尤其对于有机物中少量水的脱除或恒沸物体系及近沸物体系分离,与传统精馏、吸附、萃取等分离技术相比优势明显。强亲水性的NaA沸石膜在有机物脱水方面表现出优异的渗透蒸发性能,已经被市场化应用,但其弱的耐酸性限制了其应用范围。T型沸石膜亲水性稍弱于NaA沸石膜,但耐酸性较好,在一定强度酸性环境中具有良好的渗透蒸发性能,探索高性能T型沸石膜的成熟制备工艺,进而工业化应用具有重要意义。本文面向T型沸石膜的实际应用,以多孔粗糙的廉价氧化铝管为载体,制备了高性能T型沸石膜,进行了实验室规模放大制备,探究了其在有机物脱水方面渗透蒸发性能,主要工作内容如下:(1)以模板剂配方1 SiO2:0.055Al2O3:0.23Na2O:0.0825K2O:xTMAOH:11.68H2O(x=0.045或0.1)水热合成了2gm和0.4μm两种尺寸的结晶度高、粒径分布均匀的T型沸石分子筛;采用大小品种匹配-变温热浸渍法在粗糙的大孔廉价载体表面引入高质量晶种层,在摩尔配比为1 SiO2:0.055Al2O3:0.23Na2O:0.08K2O:30H2O的凝胶体系中水热法合成T型沸石膜,考察了晶化温度和晶化时间对膜的形貌及性能的影响,结果表明:晶化温度150℃晶化4h为较理想的合成条件,合成的T型沸石膜在75℃分离90wt.%异丙醇/10wt.%水,渗透通量为2.84 kg-m-2.h-1,分离系数为1766。(2)理想条件合成的T型沸石膜对各种90wt.%有机溶剂/10wt.%水体系具有良好的渗透蒸发分离性能;酸浸泡试验表明高浓度的酸对T型沸石膜有较强腐蚀作用;对pH=4的90wt.%异丙醇/10wt.%水体系进行长时间(120h)渗透蒸发测试表明渗透通量大于1.00kg.m-2.h-1,分离系数变化不大,说明T性沸石膜具有一定耐酸稳定性。(3)基于长为80cm的载体管进行了T型沸石膜放大制备,从晶化时间、晶化温度及晶化方式等进行条件优化,表明晶化温度为170℃晶化时间为6h旋转晶化为最佳成膜条件,放大制备的T型沸石膜渗透通量大于1.50 kg·m-2.h-1,分离系数大于10000;T型沸石膜渗透蒸发中试测试结果表明操作条件(进料温度、进料流量、进料组成)对膜的渗透蒸发性能均有不同程度的影响,高温连续渗透蒸发将异丙醇料液含水量由10%降至0.5%,平均渗透通量为1.90 kg·m-2·h-1,分离系数大于3000。
[Abstract]:Osmotic evaporation is an efficient and energy saving membrane separation technology, especially for the removal of a small amount of water from organic matter or the separation of azeotrope system and near-boiling system, which is superior to the traditional separation techniques such as distillation, adsorption, extraction and so on. The strong hydrophilic NaA zeolite membrane has shown excellent pervaporation performance in organic dehydration and has been marketed, but its weak acid resistance limits its application scope. The hydrophilicity of T-type zeolite membrane is slightly weaker than that of NaA zeolite membrane. But the acid resistance is good, and it has good pervaporation performance in a certain strong acidic environment. It is of great significance to explore the mature preparation process of high performance T-type zeolite membrane and then to apply it to industry. For the practical application of T zeolite membrane, high performance T zeolite membrane was prepared with porous and rough cheap alumina tube as the carrier. The laboratory scale was enlarged to investigate its pervaporation performance in the dehydration of organic matter. The main contents are as follows: (1) 2gm and 0.4 渭 m were synthesized by hydrothermal synthesis of 2gm and 0.4 渭 m with the template formulation 1 SiO2:0.055Al2O3:0.23Na2O:0.0825K2O:xTMAOH:11.68H2O (x0. 045 or 0. 1). T-type zeolite with uniform particle size distribution; T zeolite membrane was synthesized by hydrothermal method in gel system with 1 SiO2:0.055Al2O3:0.23Na2O:0.08K2O:30H2O molar ratio by introducing high quality seed layer on the rough surface of macroporous cheap carrier by varietal matching and variable temperature hot impregnation. The effects of crystallization temperature and crystallization time on the morphology and properties of the films were investigated. The results showed that crystallization temperature at 150 鈩,

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