膜反应器催化技术及膜催化材料的进展与展望

本文着重介绍近年来催化功能高分子膜和多孔金属或合金膜、多孔(金属)陶瓷复合膜、多孔玻璃复合膜、金属负载型复合膜与分子筛膜等选择性渗透无机膜材料的开发研究新进展及其在催化领域中的应用;列举几种典型的催化膜反应器的应用实例;指出膜反应器催化技术与膜材料的发展动向及应用前景;并对加强膜催化高技术领域的科学研究提出几点建议。     

酶膜生物反应器应用及展望

酶膜生物反应器是一种新型的、有发展前途的生物反应器，它在进行生物催化的同时，也在进行产物的分离、浓缩及催化剂的回收。介绍了酶膜反应器的概念、研究近况、特有的优点及问题。对酶膜反应器的不同分类方式及应用研究进行了综述，并加以展望。     

聚合物膜催化接触器研究进展

对聚合物膜催化接触器的特点、所用催化膜材料及其制备方法进行归纳总结。与传统催化反应器相比,聚合物膜催化接触器具有结构紧凑,工艺及操作流程简单,催化活性、反应速率及转化率高等特点。所用聚合物膜材料分子主链和侧链具有丰富的功能基团,以便引入活性纳米粒子或基团,得到高活性的催化膜。聚合物催化膜制备方法主要有杂化法、浸渍法及化学接枝法。扩散过程为聚合物膜接触器催化反应过程的控制步骤,整个过程包括内扩散和外扩散两个步骤。文中最后提出聚合物膜催化接触器应用中存在的问题,即催化效率和使用寿命有待进一步提高;新型聚合物催化膜材料亟需开发,膜污染和催化膜失活问题亟待解决;膜催化反应动力学模型的建立和研究等关键性、基础性问题还需要更加深入地研究。     

陶瓷微滤膜的制备技术与应用

综述了陶瓷微滤膜的国内外研究发展现状，介绍了一些陶瓷微滤膜的制备方法及其在膜法制乳、水处理、催化膜反应器及气体分离等领域中的应用，并对其应用前景进行了展望。     

sol-gel法制备微孔SiO2分离膜的研究进展

微孔SiO2分离膜在气体分离、催化、膜反应器等领域有着巨大的应用潜力。本文首先简要介绍了获得微孔的两种途径，然后重点对sol—gel法制备微孔SiO2分离膜的研究进展进行综述。     

氧泵型催化膜反应器中甲烷氧化偶联反应(Ⅱ)——动力学研究

在1％Sr/La_2O_3-Bi_2O_3-Ag-YSZ氧泵型催化膜反应器中,进行了甲烷氧化偶联反应动力学研究,提出了反应途径及机理,并建立了速率方程。结果表明,在该氧泵型催化膜反应器中,甲烷氧化偶联反应满足Rideal-Rdox机理。采用固体电解质电位测定技术进行了内扩散影响的考察。     

丙烷脱氢制丙烯技术研究

介绍了催化脱氢、氧化脱氢、膜反应器脱氢等几种丙烷脱氢制丙烯技术，综述了丙烷催化脱氢制丙烯催化剂的研究现状，虽然丙烷催化脱氢生产丙烯已实现了工业化，但其催化剂的性能需进一步提高；对丙烷氧化脱氢制丙烯反应催化剂的研究现状及膜反应器在丙烷脱氢反应上所具有的优越性进行了描述，认为研发具有高稳定性和高透氢性能的氢分离膜，将有望能大幅度提高丙烯的收率。     

国外膜催化剂的研究与应用

对当前国外膜催化技术(包括膜催化剂和膜反应器)的研究和应用作了全面的评述。着重考察了无机膜(各种金属膜和合金膜、陶瓷膜、各种氧化物膜、玻璃膜以及复合膜等)的催化作用,分加氢、脱氢、共轭反应、氧化还原、C_1-化学中的膜催化等进行了综述。分析了苏联、日本和美国等国家发展膜催化技术的作法,对我国开展膜催化研究提出了建议。     

微孔无机膜反应器研究

主要介绍了无机膜在化学反应中的应用－－膜反应器研究，对膜反应器的特点、类型、应用、影响因素以及与其它反应器的比较进行了评述，并对其应用前景进行了展望。     

太阳能光催化反应器的研究进展

为促进太阳能光催化反应器的研究和开发,从反应器中催化剂的存在形态、反应器的聚光形式以及应用3个方面对太阳能光催化反应器的研究现状进行了系统的综述,对催化剂悬浮型和固定膜型反应器以及聚光型和非聚光型反应器进行了比较,并分析了反应器在实际废水处理或者大批量处理中应用的可行性。     

Catalytic wet oxidation of phenol using membrane reactors: A comparative study with slurry-type reactors

The wet air oxidation of phenol over cerium mixed oxides has been carried in autoclave slurry-type reactor and also in a contactor type membrane reactor to assist about the benefits provided by the employment of the mesoporous top layer of a ceramic tubular membrane as catalyst (Ce mixed oxides) support. The effect of mixed oxide composition and use of Pt as dopant onto the phenol removal rate and selectivity towards mineralization have been studied on both types of reactor. For slurry-type reactors, two different autoclave reactors were used: one mechanically stirred highly pressurized, and the other magnetically stirred containing a porous stainless steel membrane as gas diffuser in an attempt to attain higher gas–liquid interfacial area. The performances of these reactors have been compared under similar reaction conditions (i.e. catalyst loading/liquid volume, temperature, phenol concentration) although the way in which reactants are fed to the reaction vessel (different among each other configuration) is clearly affecting the CWO phenol degradation route. From the catalytic systems studied, Pt doped Ce–Zr mixed oxides exhibit the best reaction performance in spite of the achieved phenol conversion levels are below 50%. For autoclave reactors, the gas feeding to the liquid volume by a membrane diffuser has almost no effect on phenol removal for the reaction conditions tested; whereas the catalytic membrane contactor type reactor clearly outperform autoclave reactor provided with membrane diffuser.     

陶瓷膜连续反应器的设计与工程应用

膜反应器是结合膜技术和反应器,将反应和分离两个单元操作耦合成为一个单元过程的系统,可简化流程、节约成本、提高产品质量并减少环境污染。本文就陶瓷膜连续反应器运行过程中存在的膜与反应过程优化、超细颗粒吸附、膜污染等关键问题作了阐述,并以重要的沉淀反应与非均相催化反应为对象,介绍了连续膜反应器的设计及工程应用进展。     

Vapor phase dehydrogenation of methanol to methyl formate in the catalytic membrane reactor with Cu/SiO2/ ceramic composite membrane

The Cu/SiO₂/ceramic composite membrane was prepared on the SiO₂/ceramic mesoporous membrane by an ion exchange method, and vapor phase dehydrogenation of methanol to methyl formate in the catalytic membrane reactor was investigated. It showed much better performance in the catalytic membrane reactor than that in the fixed-bed reactor under the same reaction conditions. At 240 °C, 57.3% conversion of methanol and 50.0% yield of methyl formate were achieved in the catalytic membrane reactor and only 43.1% conversion of methanol and 36.9% yield of methyl formate were achieved in the fixed-bed reactor.     

催化剂对酯化反应渗透汽化膜稳定性的影响

比较了酯化反应耦合渗透汽化膜反应器中不同的催化剂体系及其含量对ＰＰＶＡ／ＰＡＮ复合膜稳定性的影响。试验结果表明,固体超强酸催化剂体系对复合膜的稳定性没有影响。活性层酯化度为３．３％及６．２％的复合膜具有良好的稳定性。能够适合于酯化反应耦合渗透汽化过程研究及应用。     

丙烷脱氢制丙烯技术研究

介绍了几种丙烷脱氢制丙烯技术：催化脱氢、氧化脱氢、膜反应器脱氢。综述了丙烷催化脱氢制丙烯催化剂的研究现状，虽然丙烷催化脱氢生产丙烯虽已实现了工业化，但其催化剂的性能需进一步提高；综述了丙烷氧化脱氢制丙烯反应催化剂的研究现状及膜反应器在丙烷脱氢反应上所具有的优越性，认为研发具有高稳定性和高透氢性能的氢分离膜，将有望能大幅度提高丙烯的收率。     

MODELING AND SIMULATION OF A NONISOTHERMAL CATALYTIC MEMBRANE REACTOR

A two-dimensional nonisothermal mathematical model has been developed to simulate a tube-and-shell configuration, catalytic membrane reactor. The three-layer membrane consists of an inert large-pore support, an o₂ semipermeable dense perovskite layer and a porous catalytic layer. The model is applied to the simulation of the partial oxidation or methane to syngas (oxyreforming). The membrane reactor simultaneously supplies oxygen to the catalytic reaction along the reactor length, and separates oxygen from the air feed, using a dense perovskite layer which is a mixed conductor, thus allowing rapid oxygen permeation without the use of an external circuit. Two configurations of catalytic membrane reactors are simulated, for both bench-scale and industrial-scale conditions. Comparisons are made to the conventional fixed-bed reactor, and to membrane reactors which are isothermal, adiabatic or wall-cooled. The simulation results imply that the temperature rise in exothermic partial oxidation reactions may be mitigated substantially by the use of a dense membrane reactor,     

Catalytic membrane structure influence on the pressure effects in an interfacial contactor catalytic membrane reactor applied to wet air oxidation

This paper deals with the influence of catalytic membrane structure on the way the gas pressure affects the efficiency of a catalytic membrane reactor (CMR). The CMR is an interfacial contactor, used for wet air oxidation, formic acid solution and air being fed separately from both sides of the catalytic membrane. The gas overpressure can shift the gas–liquid interface into the membrane wall, closer to the catalytic zone, and therefore greatly increase the reaction rate. It has been confirmed that this was not an oxygen partial pressure effect. When compared to a conventional slurry reactor, the contactor CMR showed a reaction rate more than three times higher.     

Simulations of the effect of hydrodynamic conditions and properties of membranes on the catalytic performance of a fluidized-bed membrane reactor for partial oxidation of methane

In a fluidized-bed membrane reactor the selectivity of separation can be controlled by influencing the hydrodynamics of the fluidized bed. In this reactor type, with the mass transport limitation between bubbles and the emulsion phase, even with the non-selective membranes, high selectivity of separation can be achieved. This opens the possibility for applications of membrane reactors for reaction systems for which selective membranes do not exist, e.g. when Knudsen-type membranes or form-selective separation can not be applied. This paper is aimed at explaining the interaction between the selectivity of separation and the hydrodynamics of the fluidized bed by means of simulations that were performed for a fluidized-bed membrane reactor for catalytic partial oxidation of methane.     

Nitrobenzene liquid-phase hydrogenation in a membrane reactor

This work presents the potentialities of a catalytic membrane reactor in a gas-liquid-solid reaction. A catalytic membrane has been prepared via well-controlled platinum deposition within the porous framework of a γ-Al₂O₃ mesoporous membrane. The hydrogenation of nitrobenzene to aniline has been performed using the catalytic membrane as an active gas-liquid contactor. Some operating parameters controlling the membrane reactor performance have been explored and compared with the behaviour of conventional reactors.