Low-grade heavy oil catalytic conversion process for increasing yield of low-carbon olefins and diesel oil

Abstract

The invention relates to a low-grade heavy oil catalytic conversion process for increasing the yield of low-carbon olefins and diesel oil. The process comprises the following steps: (1) preheated low-grade heavy oil, namely raw oil, enters a zone I of a riser and is in high-temperature short-contact-time high-agent-oil ratio contact with a catalytic cracking catalyst, so as to be subjected to catalytic cracking reaction, and generated oil and gas enter a fractionating tower; (2) a top outlet material of the fractionating tower is a mixture of dry gas, liquefied gas and gasoline, a middle-part outlet material of the fractionating tower is diesel oil, a lower-part outlet material of the fractionating tower is catalyzing wax oil which is relatively difficult to crack, a bottom outlet material of the fractionating tower is oil slurry, the catalyzing wax oil enters a zone II of the riser, and the oil slurry enters a vacuum distillation tower; (3) an upper-part outlet material of the vacuum distillation tower enters the zone II of the riser and is subjected to reaction again, a middle-part outlet material of the vacuum distillation tower enters a hydrogenation device for hydrogenation, and oil slurry at the bottom of the vacuum distillation tower is subjected to treatment by an oil slurry filter and then enters a delayed coking device; (4) a low-carbon-residue easily-cracked material from the hydrogenation device enters the zone I of the riser and is subjected to reaction again. The process has the characteristics that the service life of the catalyst is prolonged, the yield of dry gases and coke is lowered, and meanwhile, the yield of low-carbon olefins and diesel oil is increased.

Description

technical field [0001] The invention relates to a catalytic conversion process for heavy oil, more specifically, to a catalytic conversion process for low-quality heavy oil that improves the yield of low-carbon olefins and diesel oil. Background technique [0002] Petroleum resources are becoming increasingly heavy and inferior, which is mainly manifested in the increase in density and viscosity of crude oil, and the content of heavy metals, sulfur, colloids and asphaltenes is getting higher and higher. Therefore, after atmospheric distillation and vacuum distillation The residual oil also presents an increasingly heavy trend. How to obtain more and better products from inferior heavy oil, such as gasoline, diesel, and low-carbon olefins, and maximize its economic utilization value has been a key issue that researchers have studied for a long time. [0003] Catalytic cracking unit is an important means of secondary processing of petroleum, and occupies a pivotal position in...

AI Technical Summary

Problems solved by technology

[0009] CN101755036 discloses a catalytic cracking process for high diesel yield and / or high propylene yield with low aromatic compound content, which is mainly based on basic materials and few large-pore zeolites or even no large-pore zeolites The catalytic composition achieves high diesel yield and / or high propylene yield, and the separated bottom product fraction is directly hydrogenated without passing through the vacuum fractionation tower, which will increase the load on the hydrogenation unit and reduce the diesel yield

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