Catalytic cracking process for poor oil

Abstract

A low-quality oil catalytic cracking process is characterized in that light diesel produced from the low-quality oil by catalytic cracking is partially or entirely reprocessed to correspondingly reduce the feed amount of fresh materials. As a result, the yield of light diesel is reduced greatly or even reduced to zero relevant to fresh catalytic material; the yields of liquefied gas and gasoline are improved greatly and the propylene yield is improved correspondingly; and the slurry oil can be partially reprocessed so that the light oil yield is improved greatly in comparison with the process for withdrawing all of the slurry oil. Since the yield of catalytic cracked diesel with low cetane number is reduced greatly, qualified commodity diesel can be prepared from straight-run diesel more easily by refinery plant.

Description

technical field [0001] The invention belongs to the technical field of catalytic cracking technology in petroleum processing, and in particular relates to a processing technology for obtaining high value-added products through catalytic cracking with inferior oil products as raw materials. Background technique [0002] The world's demand for oil is increasing, and catalytic cracking processing of inferior raw materials is an inevitable problem. As far as our country is concerned, due to insufficient supply of crude oil, the catalytic cracking units of some refineries use imported fuel oil as raw material for catalytic cracking, such as Russia's M100 fuel oil. Fuel heavy oil has very low hydrogen content, super high metal content such as Ni, V, Fe, Na, high content of polycyclic aromatic hydrocarbons, high S and N content, high density, high carbon residue value, and is difficult to crack. When using a catalytic cracking unit to process inferior raw materials, due to the dif...

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Problems solved by technology

When using a catalytic cracking unit to process inferior raw materials, due to the difficult cracking of raw materials, the cracking unit has to throw out a large amount of oil slurry, and the amount of thrown out is as high as 10-15%; the total yield of liquid products (liquefied petroleum gas, gasoline, diesel oil) is 75% %; the aromatic content of catalytic diesel oil is about 70%, the specific gravity is 0.9-0.92, the cetane number is lower than 20, the oxidation safety and light safety are very poor, after conventional hydrofining, the problem of light stability can be solved, but the specific gravity If it cannot be lowered, the cetane number will hardly increase; in order to maintain the micro-reaction activity of the catalyst at about 60, the unit oil consumption per ton of the catalyst should be above 2.5kg

As far as the refinery processing this kind of inferior oil is concerned, due to the poor quality of catalytic diesel oil, it is very difficult to blend commercial diesel oil that meets the national standard with straight-run diesel oil; it is not beneficial to sell some of them as non-standard oil. Cost-effective

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