| As a member of MFI-type zeolite membrane, silicalite-1 zeolite membrane exhibits some unique advanges compared with the common zeolite membranes, such as the straight, circular (0.51 nm×0.56 nm) pores running perpendicular to sinusoidal, elliptical (0.51 nm×0.54 nm) pores system, more stable framework structure without Al elemrnt. All these good thermal, chemical and structural stabilities as well as the hydrophobic surface property enable it applicable at high temperature under harsh conditions.In this work, the preparation technology for silicalite-1 zeolite membrane was studied in-depth and some modified synthesis methods were designed to enchance the properties of zeolite membrane; zeolite-carbon composite membranes were also synthesized to explore high H2 selective membranes; finally, the silicalite-1 zeolite membrane wih good H2 permeation performance was used as membrane reactor to promote the conversion of dehydrogenation of ethybenzen to styrene. And some conclusios can be found as follows:(1) A novel method called counter diffusion method was designed to synthesize silicalite-1 zeolite membrane. In this method the silicon source and template (which were mixted together to give a common synthesis solution) were prepared separatel, and in the next step they were applied from two sides of the support. Using this method, when the silicon and template precursors were 1SiO2:0.135Na2O:100H2O:4C2H5OH and 1.5TPABr:100H2O, the silicalite-1 membrane has better morphology structure and gas permeation, such as at room temperature it has H2 permeance of 7.29×10-7 mol·m-2·s-1·Pa-1 and H2/SF6 ideal selectivity factors was 103, respectively, higher than the Knudsen value. In this work template was restricted in limited space and its availability was enhanced remarkably.(2) Composite seeding technology was developed for the low cost alumina supports. In this method large zeolite crystals were coated on the support first and then small seeds were coated on the pro-modified support to give a well seeded support. Restricted growth method was developed to prepare silicalite-1 membranes and some parameters were investigated, such as the water/Si, template type, crystallization temperature, et al. Results showed silicalite-1 membrane can be synthesized under high water/Si ratio such as 1200. When water/Si=800, TPAOH as template, crystallization temperature 443 K, the silicalite-1 zeolite membrane has H2 permeance of 1.23×10-6 mol·m-2·s-1·Pa-1 andαH2/SF6 of 134.(3) Microwave heating replaced the conventinonal heating to synthesize silicalite-1 zeolite membrane. With microwave heating in-situ crystallization can not prepare continuous zeolite membrane, even the crystallization temperature was 423 K and crystallization time was 3 h. While using the secondary growth method well-intergown silicalite-1 membranes were synthesized. Crystallization temperature, time and molar ratios of synthesis solution have significant effects on silicalite-1 membranes. When the synthesis solution has molar composition of 1TEOS:0.3TPAOH:80H2O, at 393 K,423 K and 453 K the growth rates of zeolite layer were about 0.83μm/h,1.2μm/h and 2.16μm/h. Under optimized conditions the silicalite-1 membrane has H2 permeance of higher than 2×10-6 mol·m-2·s-1·Pa-1 andαH2/SF6 higher than 160.(4) Some parameters for the preparation of zeolite-carbon composite membranes were investigated systematically, including the concentration of resin, the content and particle size of zeolite crystals, coating times and carbonation temperature programming profile. When the concentration of resin was 40%, the content and size of zeolite were 1.5wt% and 200 nm, respectively, the coating time is twice, the as-prepared composite membrane was smooth, dense and uniform without obvious defects, and the thickness was about 4μm。At room temperature it has H2 permeance of 1.16×10-7mol·m-2·s-1·Pa-1,αH2/N2 andαH2/CH4 of 181 and 227, respectively. At 973 K, its H2 permeance was up to 2.3×10-7mol·m-2·s-1·Pa-1, andαH2/CH4 up to 45.(5) Using thermodynamic data the conversations of ethylbenzene at different temperature, water/ethylbenzene feed ratio and H2 removal content were calculated for the reaction of dehydrogation of eythenbenzen to styrene, which proved the feasibility of membrane reactor for this reaction. The influence of reaction temperature, water/eythenbenzen feed ratio and vacuum degree of permeate side was investigated. The results showed as the increase of reaction temperature and water/eythenbenzen feed ratio the conversations of the two reactors were increased, moreover the conversation in membrane reactor was higher than that in the fixed-bed reactor. In the vacuum degree range of 0.02-0.1MPa in permeate side, the conversations exhibited a maximal value. When water/ethylbenzene was 14:1, space velocity was 0.5 h-1 and vacuum degree was 0.06 MPa at 893 K, the conversation in membrane reactor was about 80.7%, higher than that in fixed-bed reactor by 13%, moreover the selectivity of styrene was about 95%.
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