本文選題：分子篩膜　切入點：滲透汽化　出處：《華東理工大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：為了實現(xiàn)乙酸乙酯粗產(chǎn)物中二元、三元共沸體系的低能耗高效分離,采用雙晶種熱浸漬法在大孔α-Al_2O_3陶瓷管外表面合成了均勻致密的A型分子篩膜,并考察其對乙酸乙酯-水及乙酸乙酯-乙醇-水體系的分離效果,揭示了 A型分子篩膜的合成條件對膜結(jié)構(gòu)的調(diào)控作用以及膜結(jié)構(gòu)對分離性能的影響機制。首先采用水熱法合成了與α-Al_2O_3陶瓷管表面孔隙相當(dāng)?shù)牧郊s為2.0 μm的A型分子篩晶種L,用于修飾填補載體表面缺陷;并合成了粒徑約為0.4 μm的A型分子篩晶種S,用于導(dǎo)向合成均勻致密的A型分子篩膜。通過優(yōu)選涂晶條件、母液配比、晶化時間、晶化次數(shù)等合成工藝條件調(diào)控A型分子篩膜的結(jié)構(gòu)和性能。在優(yōu)化的涂晶條件下,控制母液摩爾配比為n(Al_2O_3):n(SiO2):n(Na_2O):n(H_2O)=1:5:50:1000,在晶化溫度70℃、晶化時間6h的條件下可以合成結(jié)構(gòu)規(guī)整、表面致密、結(jié)晶度高的厚度約為10 μm的A型分子篩膜。采用合成的A型分子篩膜對乙酸乙酯-水體系進行滲透汽化分離,考察了進料流率、操作溫度對水的滲透通量及分離因子的影響,揭示了膜結(jié)構(gòu)對分離性能的影響機制。在操作溫度為110℃條件下,乙酸乙酯中水含量為3%時,滲透液水含量為99.68%,分離因子約為10000,滲透通量為1.72 kg/(m~2·h)。循環(huán)后滲余液中水含量可降至0.02%,達到乙酸乙酯優(yōu)等品的國標(biāo)要求,此時滲透液水含量為99.23%,分離因子可達210000。隨著分子篩膜厚度的增加,滲透通量降低,分離因子增加。合成的高結(jié)晶度A型分子篩膜對乙酸乙酯-水體系具有優(yōu)異的分離性能。與乙酸乙酯分子相比,乙醇分子因動力學(xué)直徑小而更易通過A型分子篩膜,分離難度增加。合成A型分子篩膜對乙酸乙酯-乙醇-水三元共沸體系也具有較好的脫水分離性能,滲透通量為1.97 kg/(m~2·h),分離因子大于8500。
[Abstract]:In order to realize the separation of binary and ternary azeotropic system from ethyl acetate, a homogeneous and compact zeolite A membrane was synthesized on the outer surface of macroporous 偽 -Al _ 2O _ 3 ceramic tube by bimorph seed hot impregnation method. The separation efficiency of ethyl acetate water and ethyl acetate ethanol water system was also investigated. The effects of synthesis conditions on membrane structure and the mechanism of membrane structure affecting separation performance were revealed. Firstly, A with a diameter of about 2.0 渭 m equivalent to 偽 -Al _ 2O _ 3 ceramic tube surface porosity was synthesized by hydrothermal method. Type A zeolite seed L, which is used to modify and fill the surface defects of the carrier. A molecular sieve type A seed, about 0.4 渭 m in diameter, was synthesized, which was used to guide the synthesis of homogeneous and dense zeolite A membrane. The optimized coating conditions, the ratio of mother liquor and the crystallization time were used. The structure and properties of type A molecular sieve membranes were regulated by crystallization times and other synthetic conditions. Under the optimized coating conditions, under the optimized coating conditions, the structure and surface density could be synthesized by controlling the molar ratio of nnAl2O3: n / SiO _ 2: n / N _ 2O _ 2: s / N / N _ 2O / H _ 2O 1: 5: 50 / 1000 under the conditions of crystallization temperature 70 鈩，

本文編號：1647807