Method for use of modified molecular sieve catalyst in catalytic cracking of propane

Abstract

Belonging to the technical field of catalysts, the invention relates to a method for use of a modified molecular sieve catalyst in catalytic cracking of propane. The method is characterized by subjecting a molecular sieve to a full negative pressure degassing purification treatment, and then loading a gold precursor onto a molecular sieve carrier by a negative pressure deposition-precipitation technique, thus obtaining a uniform and highly disperse granule loaded nanogold catalyst. The molecular sieve refers to a high-silicon zeolite molecular sieve. Preparation of the loaded gold catalyst through the deposition-precipitation technique under a negative pressure condition is in favor of purifying the inner and outer surfaces of the molecular sieve and pore channels, so that Au can be easy to enter the pore channels of the molecular sieve and high dispersion can be achieved. The method provided in the invention can make propane undergo dehydrogenation to produce olefin under the difunctional actions of the metal and the carrier. The olefin can acquire protons at an acid site to form carbonium ions, which then undergo polymerization cracking to generate corresponding olefin.

Description

technical field [0001] The invention belongs to the technical field of catalysts, and relates to a method for catalytically cracking propane with a modified molecular sieve catalyst. Background technique [0002] Propane comes from oilfield liquefied gas, and can also come from secondary processing of petroleum. Propane can be used as raw material for steam cracking and dehydrogenation. In the steam process, propane is dehydrogenated to propylene through a free radical reaction. The dehydrogenation reaction of propane includes catalytic oxidative dehydrogenation and catalytic dehydrogenation. The products in the oxidative dehydrogenation process are complex and difficult to separate, the yield of olefins is low, and deep oxidation is prone to occur. At present, the catalytic dehydrogenation processes that have been industrialized include Oleflex process and Catofin process. The catalyst systems are Pt-based and Cr-based respectively. Their common disadvantage is that they ...

AI Technical Summary

Problems solved by technology

When ZSM-5 is used as a carrier, only supported gold catalysts with gold particles of 40-50nm can be obtained, and Au / ZSM-5 catalysts with smaller particles cannot be obtained