Method for producing low-carbon olefin

Abstract

The invention discloses a production method for low carbon alkene. The catalytic cracking catalyst is risen by a pre-lift medium and then is reacted with raw material in a reactor, product obtained and spent catalyst obtained after the reaction are drawn from the reactor to be separated, the separated spent catalyst is made a burning regeneration and returns to the reactor for repeated use, the separated reaction product is fractionated, then the low carbon alkene, the gasoline, the diesel, the heavy oil and other low molecular saturated hydrocarbons are obtained. The invention is characterized in that: the change range of the density of the catalyst in the reactor is between +-1 and 20 percent, the change range of gas velocity of a non-catalyst hollow tower is between +-1 and 18 percent.With the method provided by the invention, the oil gas speed and the catalyst density in the reactor have small changes, the fluidized state is relatively steady, the mass transfer speed and the temperature are evenly distributed in the reactor, so the method provided by the invention has high heavy raw material conversion rate, improves the yield and the selectivity of the low carbon alkene, anddecreases the yield of the dry gas.

Description

technical field [0001] The invention relates to a method for catalytic conversion of hydrocarbon oil in the absence of hydrogen, more specifically, a method for catalytic cracking conversion of heavy raw materials into low-carbon olefins rich in propylene and ethylene. Background technique [0002] In the process of fluidized catalytic cracking or fluidized catalytic cracking, the high-temperature regenerated catalyst contacts and reacts with raw oil. The main products are gasoline and diesel, and a part of liquefied gas, dry gas, oil slurry and coke are also produced. The coke is deposited on the spent catalyst and enters the regenerator together with the spent catalyst to be burnt to restore activity, and the regenerated catalyst whose activity has been restored enters the reactor for recycling. [0003] In recent years, the demand for low-carbon olefin chemical raw materials represented by ethylene and propylene has grown rapidly, and more and more catalytic cracking or c...

AI Technical Summary

Problems solved by technology

[0011] The above-mentioned prior art supplements part of the regenerated catalyst during the reaction process of the riser reactor in an effort to improve the shortcomings of the traditional riser reactor due to the large changes in oil gas velocity and catalyst density, and the corresponding large changes in the fluidization state in the reactor, but still Unable to guarantee a relatively stable fluidized state, mass transfer rate and uniform temperature distribution

Images