Preparation Of Co/Silicalite-1 Monolithic Catalysts For Fischer-Tropsch Synthesis

The classical granular catalysts possess many drawbacks, such as high pressure drop and unnegligible concentration and temperature gradients, but the monolithic catalysts can just make up for those disadvantages. Because of the advantages, such as excellent ductility, higher thermal conductivity, greater thermal, corrosion and mechanical shock resistance, the metallic substrate has displayed a great potential in some three-phase reaction systems. Now, the metallic substrate is widely used in field of environmental protection as gas processing of automobile exhaust and industrial emissions, and also is applied in petroleum chemical industry, but many processes are still in researching stage.Discovered by German scientists in 1923, F-T synthesis has been industrialized for several decades, but it is still a popular research topic both at home and abroad. Because of significantly exothermal, catalyst beds are often local overheating in the F-T process, which lead to low selectivity for products, the catalysts carbon deposition, even block of catalyst beds. Application of the monolithic catalysts can solve the above problems, which is researched both in home and abroad. But in the catalyst preparation, these researches all followed the classical granular catalysts preparation methods, then washcoated on the metallic substrate. So, the falling of unstable coating may also result these problems.In this paper, monolithic catalysts have been synthesized on the stainless steel pieces and spiral pieces by in-situ hydrothermal synthesis, electrochemical deposition and incipient wetness methods. Compared with direct coating, the coating synthesized by in-situ hydrothermal synthesis is continuous and compact. It is not only strengthen the mass and heat transfer on the catalyst surface, but also more soundly. At last, the new-style Co/Silicalite-1 monolithic catalysts with certain shape stainless steel supports for F-T synthesis were prepared, in addition, the catalytic performance were evaluated. The results show that the catalysts exhibited lower CH4 selectivity, especially the yield of gasoline and diesel was 97.41%.This paper includes the following aspects:Firstly, Silicalite-1 zeolite membranes were synthesis on stainless steel pieces. Effects of removal of template, different electro-deposition density and electro-deposition time on cobalt electro-deposition; effects of different electro-deposition time on Silicalite-1 zeolite membranes; effects of different impregnation processes on the loading of active component were studied.Secondly, the stainless steel was amplified 20 times and rolled into spiral as support, the Co/Silicalite-1 monolithic catalysts for F-T synthesis were prepared by in situ hydrothermal synthesis, electrochemical deposition and incipient wetness. In addition, each of the steps were compared with the single chips'and optimized.Finally, with stainless steel spiral pieces as support, the Co/Silicalite-1 monolithic catalysts for F-T synthesis were prepared by in situ hydrothermal synthesis, electrochemical deposition and incipient wetness. Moreover, the reaction performance was evaluated.