A catalyst for catalytic cracking to prepare alkenes and a preparing method thereof

Abstract

A catalyst for naphtha catalytic cracking to prepare ethylene and propylene is disclosed. Based on the weight content of the catalyst, the catalyst comprises 40-90% of an MFI molecular sieve subjected to metal isomorphous substitution, 0.1-2.5% of a rare earth metal oxide and 0.2-2.0% of heteropoly acid. In the molecular sieve, Al in the molecular sieve is all or partially substituted by a metal, and the substituting metal is one or more selected from magnesium, calcium, zinc, gallium, and the like. A preparing method of the catalyst includes (1) substituting all or a part of the Al in the ZSM-5 molecular sieve by the selected substituting metal to prepare the ZSM-5 molecular sieve subjected to metal isomorphous substitution, (2) selecting a proper adhesive, pulping a proper amount of the heteropoly acid, a proper amount of the adhesive and the ZSM-5 molecular sieve subjected to metal isomorphous substitution in the step (1) to prepare a suspension, drying the suspension and then performing strip extrusion and molding, and (3) performing loading of the rare earth metal oxide through a hot-carrier dipping method, and drying the product after dipping to obtain the final catalyst. The catalyst has advantages of high alkene yields, low reaction temperatures, good catalyst stability, and the like.

Description

technical field [0001] The invention relates to a catalyst for producing olefins by catalytic cracking and a preparation method thereof, in particular to a catalyst for producing ethylene and propylene by catalytic cracking of naphtha, a preparation method and application thereof. Background technique [0002] Since the beginning of the new century, the world’s demand for petrochemical raw materials and petrochemical products will continue to grow, and the demand for ethylene and propylene, which are the basic petrochemical raw materials, will continue to grow. However, the production capacity of conventional steam pyrolysis technology cannot meet the rapidly growing demand for propylene. Furnace steam pyrolysis is a process that consumes a lot of energy, and the process conditions are harsh. Compared with steam thermal cracking, the reaction temperature of naphtha catalytic cracking is about 50-200°C lower than that of steam thermal cracking. Therefore, it consumes less ene...

AI Technical Summary

Problems solved by technology

[0007] Aiming at the shortcomings of existing naphtha catalytic cracking to produce ethylene propylene, such as low yield, high reaction temperature, and easy deactivation of the catalyst, the present invention provides a catalyst for producing ethylene propylene by naphtha catalytic cracking and a preparation method thereof