Hydrogen molecular sieve, preparation method thereof and application in preparing propylene from methyl alcohol

Abstract

The invention provides a hydrogen molecular sieve, a preparation method thereof and application in preparing propylene from methyl alcohol. According to the preparation method, a silicon source and an aluminum source serve as raw materials, under the combined action of a dual-template and a structure-directing agent and by means of hydrothermal crystallization achieved through a crystallization regulator, a molecular sieve crystal is obtained, and then the hydrogen molecular sieve is obtained through roasting and exchange. The hydrogen molecular sieve prepared through the preparation method serves as a catalyst for preparing propylene from methyl alcohol through conversion, the propylene selectivity can reach 47.4%, the total aromatic selectivity is lower than 2%, and the service life of the catalyst reaches 2100 h. Compared with a method using ZSM-5 as a catalyst, the propylene selectivity is increased by about 10-28.5%, and the service life is prolonged to 1.9-2.5 times that of ZSM-5.

Description

technical field [0001] The invention relates to the technical field of functional materials, in particular to a hydrogen-type molecular sieve, its preparation method and its application in methanol to propylene. Background technique [0002] Olefins, especially light olefins (C 2-4 =), is an important chemical raw material to meet industrial production and people's life. Ethylene and propylene produce industrial products such as polyethylene and polypropylene through polymerization; ethylene, propylene and butene can also be oxidized to produce fine chemicals such as acetaldehyde, acrylic acid, acrolein and butenedioic anhydride. So far, low-carbon olefins are mainly obtained through steam cracking of light hydrocarbons and naphtha, and these routes rely too much on petroleum. Today's oil prices are soaring and oil resources are increasingly scarce. The world's major oil companies are vigorously developing processes for the production of low-carbon olefins using non-oil re...

AI Technical Summary

Problems solved by technology

[0005] The skeleton of ZSM-5 hydrogen-type molecular sieve is composed of two crossed ten-membered ring channel systems. The straight cylindrical ten-membered ring channel is elliptical, and the major axis is Minor axis is The other is the "Z"-shaped transverse ten-membered ring channel, the cross-section is close to a circle, and the pore diameter is The moderate pore size and three-dimensional pore structure of ZSM-5 hydrogen molecular sieve are conducive to the diffusion of MTP reactants and product molecules, and are not conducive to the formation of carbon deposits. It has the advantage of long life in the MTP reaction. However, its disadvantage is that ethylene in the target product The selectivity of propylene and propylene is not ideal, and the selectivity of aromatics in its product is relatively high

In contrast, SAPO-34 forms a larger ellipsoidal cage at the intersection of the internal pores of the hydrogen-type molecular sieve, and the size of the cage is Each cage communicates with other cages through a total of 6 eight-membered rings on the side to form a three-dimensional intersecting channel. The size of the orifice is the eight-membered ring, and the aperture is SAPO-34 exhibits a strong shape-selective effect on low-carbon hydrocarbon molecules. In the MTO reaction, the selectivity of ethylene and propylene is high, but its disadvantages are fast coking deactivation and short life

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