The Study Of Methanol To Propylene Catalysts And Preliminary Exploration Of Preparation

Methanol to propylene catalyst is a kind of solid catalyst which make the advantage of acidity of molecular sieve and selectivity of special hole structure to produce propylene from methyl alcohol. The manufacturing process mainly include two parts:the first is the synthesis and preparation of ZSM-5 molecular sieve; the second is the molding of the catalyst. Therefore, the first step is the analysis on the morphology and structure of the good the methanol to propylene catalysts purchasable in the market, followed by synthesis and preparation of ZSM-5 molecular sieve and production of the catalyst.The result of analysis of catalyst for commercial indicate that:(l)The particles of the compressive strength of catalyst for commercial use does not drop significantly after the reaction, which meets the requirement of production. (2)It can be also confirmed that the main component is ZSM-5 molecular sieve, with four elements Si, Al, O and C. After the reaction, the grains change from nanoscale to spheroidal particle of one micrometer. At the same time, the proportion of Al drops due to the fact that overheating saturation and vapour treatment cause the dealumination of molecular sieve.The synthesis experiment of ZSM-5 molecular sieve explores two ways of synthesizing ZSM-5 molecular sieve, namely with and without template and discusses the influence the conditions have on crystallinity and the form of products. The research finds that:(1) When PH is between 10 and 11, it is easier to lead to hydro-thermal synthesis of ZSM-5 molecular sieve. (2)As silicon source, TEOS contributes to crystallinity of products, which increase with the time. However, after the crystallinity is sufficient, the crystallinity decreases with time. (3)during the ageing process, adding stirring condition contributes to crystallinity of products. (4)Synthesis without template process needs more nucleation time and crystallinity time and best time of ageing time is 24 hours, exceeding which does not contribute to crystallinity. (5)The the primary particle of product synthesis without template is coffin cube, while the synthesizes with template is long prismatic type. (6)Product synthesis without template finds examples that irregular types, like gel filtrate change into regular types, as well as two different types of primary particles.The research conducts processing experiment of catalyst, which discusses the influence that the type and density of acid have on compressive strength and particle density of the catalyst. The result indicate that:(1)The particle density according to the acid used can be ranked as followed:nitric acid> phosphoric acid mixed with nitric acid> citric acid.(2)The compressive strength according to the acid type can be ranked:nitric acid> phosphoric acid mixed with nitric acid> citric acid. Besides, the compressive strength of samples of nitric acid phosphoric acid increases with density of acid.