Research on catalytic cracking process with low green coke and high yield of low carbon olefins

The catalytic cracking process with high reaction severity for high production of light olefins leads to the problem of excessive coke yield due to high conversion rate.The concept of optimizing the properties of the catalytic cracking feedstock ,the molecular structure of the feedstock oil and the effective space constraints of the catalyst pores are proposed.Therefore, the research idea of catalytic cracking process with low green coke and high low carbon olefin yield is formed.The test results show that: for the hydrogenated heavy oil which is not suitable for the production of low-carbon olefins.Removal of resin and asphaltenes from hydrogenated heavy oil by combined solvent deasphalting and catalytic cracking technology.Deasphalted oil is used as the feedstock for catalytic cracking, and the coke yield is greatly reduced.For the Daqing wax oil with high saturated hydrocarbon content, the space confinement effectiveness of the mesoporous MFI molecular sieve channels (TCC-1 catalyst) and Daqing wax oil molecules is obviously better than that of the macroporous Y molecular sieve (MMC-2 catalyst).Coke yield decreased by 28.9% and olefin product yield increased by 6.3%.When using hydrogenated wax oil with high aromatic hydrocarbon content, as the content of polycyclic aromatic hydrocarbons in the reactant increases, the condensation reaction of polycyclic aromatic hydrocarbons on the mesoporous MFI molecular sieve is also difficult to effectively inhibit.These research results provide a deeper theoretical understanding for the further development of medium pore molecular sieve heavy oil catalytic cracking technology with low green coke, low energy consumption and high olefin products.

It provides a more reliable theoretical basis for the development of refining transformation and development technology.