本文選題：小孔沸石分子篩膜　切入點：大孔載體　出處：《大連理工大學》2015年博士論文　論文類型：學位論文

【摘要】：在微孔材料中,小孔沸石分子篩(如：SAPO-34、AlPO-34及DD3R)由于具有較小的孔徑和良好的熱力學、化學及結構穩(wěn)定性,被廣泛認為是理想的氣體分離膜材料,尤其對小分子氣體具有較好的滲透分離作用。然而多數(shù)小孔沸石分子篩成膜困難,為使其在載體表面成核均勻、獲取較高的分離選擇性,通常將其制備于表面平均孔徑較小的載體上,這不但極大提升了制膜成本,也使氣體滲透通量大幅度降低,不利于工業(yè)化進程的推進。本文以廉價的大孔α-Al2O3為載體,制定不同的制膜策略,構建高性能小孔沸石分子篩膜,主要工作如下： (1)為修飾大孔載體表面缺陷,提高載體與晶種層之間的結合力,從而在廉價大孔載體上制備出高性能的SAPO-34分子篩膜,提出蒸汽輔助轉(zhuǎn)化涂晶方法,將含有晶種的干凝膠漿料涂覆于大孔載體表面,經(jīng)過蒸汽轉(zhuǎn)化作用使凝膠層晶化成晶種層,并系統(tǒng)考察了摻雜晶種尺寸及干凝膠漿料涂覆次數(shù)對SAPO-34分子篩膜的影響。研究發(fā)現(xiàn),當涂覆2次含500nm晶種的干凝膠漿料時制得的晶種層薄而連續(xù),在此基礎上制備的SAPO-34分子篩膜顯示了良好的氣體分子篩分作用,其中H2通量高達6.96×10-6mol·m-2s-1Pa01, H2對CH4、C3H8及i-C4H10的理想選擇性分別為14.8、26.5及53.0。 (2)為簡化SAPO-34分子篩膜的制膜工藝,有效利用有機模板劑,提出晶種誘導干凝膠轉(zhuǎn)化法。通過優(yōu)化制膜條件,分別考察了涂覆干凝膠的濃度、凝膠中摻雜晶種的尺寸及蒸汽相組成對成膜的影響,從而得到高質(zhì)量的SAPO-34分子篩膜,對該膜進行氣體滲透性能表征,H2通量為7.04×10-6mol·m-2s-1Pa-1, H2/C3H8和H2/i-C4H10理想選擇性可達25.4及50.6。探討了該方法的成膜機理,當蒸汽相中含有模板劑時,其與干凝膠中的模板劑共同作用,有利于凝膠層中晶核的生成,進而有效填補了晶間缺陷。 (3)為提高大孔載體表面晶體成核密度,制備出連續(xù)且孿生性較好的AlPO-34分子篩膜,采用綠色可循環(huán)的離子液體作為溶劑,利用二次生長法,在無模板劑N-甲基咪唑(N-MIm)的條件下分別對HF含量、晶種層的種類及水的含量等條件進行考察。在適量水及晶種層的共同作用下,制備得到了高質(zhì)量的AlPO-34分子篩膜,并取得了較好的氣體滲透性能,H2通量為9.74×10-8mol·m-2s-1Pa1, H2/CO2、H2/CH4、H2/C3H8以及H2/i-C4H10理想選擇性分別為7.49、14.6、39.3及65.8,優(yōu)于離子熱下制備的其它分子篩膜。 (4)為縮短Si-DD3R分子篩的誘導期,利用微波輔助法,在氟離子及乙二胺(EDA)的雙助劑作用下,可得到含晶核的前軀體,經(jīng)干凝膠轉(zhuǎn)化后制備了尺寸約為30nm的Si-DD3R分子篩,合成時間由25天縮短至4天。利用前軀體中晶核的誘導作用,經(jīng)球磨晶種誘導干凝膠轉(zhuǎn)化涂晶法,提高載體表面成核點,考察了干凝膠轉(zhuǎn)化時間對晶種層及膜層的影響,其中轉(zhuǎn)化3天后的晶種層可誘導出連續(xù)且結晶度較高的膜層,H2/i-C4H10理想選擇性為43.8。為進一步提高膜的性能,提出二次修補法,以Si-DD3R的缺陷膜為基底膜,進行打磨處理,使大量晶核暴露出來,增加載體表面成核密度。優(yōu)化二次生長條件,在較高合成凝膠濃度下所制得的Si-DD3R分子篩膜具有良好的滲透分離性能,H2通量為7.35×10-8mol·m-2s-1Pa-1,H2對CH4、C3H8及i-C4H10理想選擇性分別達到8.77、29.2及57.4。對其進行溫度依存性測試,并與SAPO-34及AlPO-34分子篩膜對比,Si-DD3R分子篩膜在較苛刻的條件下依然可以保持較高的分離性能,展示了小孔分子篩膜在一些實際分離中的潛在應用價值。
[Abstract]:In microporous materials, pore zeolite molecular sieve (such as: SAPO-34, AlPO-34 and DD3R) as with a smaller pore size and good thermal, chemical and structural stability, is widely regarded as the ideal gas separation membrane materials, especially for small molecular gas has good separation effect. However, the majority of penetration into the hole zeolite molecular sieve in order to make the film difficult, on the surface of the carrier nucleation uniformity, obtain higher selectivity, usually the preparation of carrier on the surface of average pore size smaller, which not only greatly enhance the preparation cost, the gas permeation flux is greatly reduced, is not conducive to the advancement of industrialization. In this paper, macroporous alpha -Al2O3 cheap as the carrier, making films of different strategies, construct high performance pore zeolite membrane, the main work is as follows:
(1) for the modified macroporous carrier surface defects, improve the binding force between the carrier and the seed layer, thus producing high performance SAPO-34 molecular sieve membrane in inexpensive macroporous support system, put forward the steam assisted conversion coating method, containing seed dry gel slurry is coated on the surface of the macroporous carrier, after the effect of steam reforming of gel layer crystallization into the seed layer, and investigated the effect of doping the crystal size and dry gel coating times on SAPO-34 zeolite membrane. The study found that the coating containing 2 500nm seed seed dry gel slurry prepared thin and continuous, SAPO-34 molecule on the basis of preparation of zeolite membranes showed good gas molecular sieving effect, the H2 flux is 6.96 * 10-6mol, m-2s-1Pa01, H2 on CH4, C3H8 and i-C4H10 ideal selectivity were 14.8,26.5 and 53.0.
(2) to simplify the membrane preparation process of SAPO-34 molecular sieve membrane, the effective use of organic template, the seed induced by the dry gel conversion method. Through the optimization of preparation conditions were investigated, the concentration of gel coating dry gel size and vapor doping seed phase composition on the influence of the film, so as to get the SAPO-34 zeolite membrane with high quality, gas permeability characterization of the membrane flux is 7.04 * 10-6mol, H2, m-2s-1Pa-1, H2/C3H8 and H2/i-C4H10 and 50.6. ideal selectivity up to 25.4 of the film forming mechanism of the method, when the vapor phase contains the template, the template interaction with dry gel, is conducive to the gel layer MICROTEK nuclear generation, thus effectively fill the intergranular defects.
(3) to improve the nucleation density of crystal macroporous carrier surface prepared by continuous and twin well AlPO-34 molecular sieve membrane, using ionic liquid as solvent green can be recycled two times, using the method of growth, in the absence of template N- methyl imidazole (N-MIm) conditions respectively for HF content of to investigate the seed layer type and water content. In the interaction of water and seed layer, prepare AlPO-34 zeolite membrane with high quality, and achieved good gas permeability, H2 flux is 9.74 * 10-8mol, m-2s-1Pa1, H2/CO2, H2/CH4, H2/C3H8 and H2/i-C4H10 ideal selectivity were 7.49,14.6,39.3 and 65.8, better than the ion thermal for other molecular sieve membrane preparation.
(4) for the induction period of Si-DD3R molecular sieve, using microwave assisted method in fluorine ion and ethylenediamine (EDA) of the two additives, can be obtained with the nucleation precursor by dry gel conversion after preparation of the size of Si-DD3R 30nm molecular sieve, the synthesis time is shortened from 25 days to 4 days. Using the induction effect of the precursor of MICROTEK core seed induced by ball milling, dry gel conversion coating method, improve the nucleation point on the surface of the carrier, the dry gel conversion time of seed layer and coating effects, including 3 days of the seed layer can induce the crystallization degree is high and continuous film the H2/i-C4H10 ideal selectivity for 43.8. to further improve the performance of the membrane, the two repair method, basement membrane to membrane Si-DD3R defects, grinding processing, so that a large number of nuclei exposed, increase the nucleation density of the surface of the carrier. The two optimal growth conditions in the synthesis of high concentration gel Si-DD3R molecular sieve prepared under membrane has good separation performance, H2 flux is 7.35 * 10-8mol, m-2s-1Pa-1, H2 on CH4, C3H8 and i-C4H10 were respectively 8.77,29.2 and 57.4. ideal selectivity of the temperature dependence of the test, and sieve membrane compared with SAPO-34 and AlPO-34 molecules, Si-DD3R molecular sieve membrane in more demanding the conditions can still maintain a high separation performance, showing the small molecular sieve membrane separation in some practical application value.

【學位授予單位】：大連理工大學
【學位級別】：博士
【學位授予年份】：2015
【分類號】：TQ051.893

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