Molecular sieve catalyst for preparing propylene from methanol/dimethyl ether and preparation method thereof

Abstract

The invention relates to a molecular sieve catalyst for preparing propylene from methanol / dimethyl ether and a preparation method thereof. The molecular sieve catalyst is prepared from the following raw materials in molar ratio and ZSM-5 molecular sieve crystal powder serving as a guiding agent: YO2 / X2O3 is equal to 80 to 1,500, H2O / YO2 is equal to 4 to 80, M2O / YO2 is equal to 0.01 to 0.5, and R / YO2 is equal to 0.2 to 5.0, wherein Y is a tetravalent element; and X is a tervalent cation; and M is an alkali metal. A template agent R is straight-key CH3-(CH2)n-NH2 or NH2-CH2-(CH2)n-CH2-NH2, wherein n is an integer of 1 to 6; and the template agent is ethamine, ethylene dimine or n-butylamine. The molecular sieve catalyst is a porous crystalline material (an NDF molecular sieve) with an MFI structure; the weak acid content is more than the strong acid content; the catalyst prepared by using the molecular sieve as a parent substance runs for 600 hours in a small-scale reaction of preparing propylene by using methanol / dimethyl ether, wherein the propene selectivity is 48 to 53 percent and P / E is equal to 6 to 8. The preparation method is suitable for industrial mass production, guarantees the performance of the catalyst, is eco-friendly in production, and generates little sewage which is easy to be treated.

Description

Technical field: [0001] The present invention relates to the preparation of catalysts, in particular to a molecular sieve catalyst and preparation method for methanol / dimethyl ether to produce propylene, in particular to a parent molecular sieve (referred to as For: NDF molecular sieve) synthesis and application. Background technique: [0002] As an important petrochemical raw material, the demand for propylene has increased significantly. In the world, especially in today's rapid economic development in my country, the production of propylene is far from meeting the needs of consumption. At present, propylene is mainly derived from the by-products of petroleum refining or ethylene engineering. This is far from meeting the needs of economic development. At present, in the production of the petroleum industry, every effort is made to increase the output of propylene, but with the gradual depletion of petroleum reserves and the rise of petroleum prices, it is very urgent to...

AI Technical Summary

Problems solved by technology

Many domestic patents use the method of metal modification and dealumination of molecular sieves, but in large-scale production, it will cause corrosion of equipment and produce a large amount of acidic sewage, which will cause environmental pollution.

There are also patents that use expensive silicon sources, expensive quaternary ammonium salts, and quaternary ammonium bases as guiding agents, and add organic additives to synthesize ZSM-5 molecular sieves, which will produce a large amount of organic sewage during the production process. In sewage treatment It will cost a lot of money, which also needs to be further solved

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