A catalyst for catalytic cracking to prepare olefins, a preparing method thereof and applications of the catalyst

Abstract

A catalyst for catalytic cracking to prepare olefins, a preparing method thereof and applications of the catalyst are disclosed. The catalyst includes, by weight, 5-30% of an alkaline earth metal-modified MFI molecular sieve and 0.1-3% of heteropoly acid, with the balance being SiO2, wherein the weight of the alkaline earth metal is 0.5-2% of the weight of the MFI molecular sieve. The preparing method includes (1) weighing a proper amount of the heteropoly acid, dissolving the heteropoly acid into water and fully stirring the solution, (2) adding a proper amount of an ethanol solvent and a proper amount of a silicon-containing precursor into the solution obtained in the step (1), fully stirring the solution, and adjusting the pH value of the solution to be 1-7, (3) adding the alkaline earth metal-modified MFI molecular sieve into the solution in the step (2), fully stirring the solution at a constant temperature, then adding an ionic liquid, and continuously stirring the solution until the solution is converted into sol, and then performing room-temperature ageing to obtain gel, and (4) drying the gel in the step (3) until the weight is constant and grinding the dried gel to obtain the catalyst for catalytic cracking. The catalyst has advantages of a high olefin yield, 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 its preparation method and application, in particular to a catalyst for producing ethylene and propylene by catalytic cracking of naphtha and its preparation method and application. 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℃ lower than the standard cracking reaction. Therefore, it consumes le...

AI Technical Summary

Problems solved by technology

[0007] The above-mentioned catalysts generally have one or more deficiencies such as high cost, low olefin yield, high reaction temperature, too fast catalyst deactivation, and poor stability.