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

Abstract

The invention relates to a low-grade heavy oil catalytic conversion process for increasing the yield of low-carbon olefins and gasoline. The process comprises the following steps: (1) low-grade heavy oil, namely raw oil, enters a first reaction zone (zone I) of a two-section riser, 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, a bottom outlet material of the fractionating tower is oil slurry, the catalyzing wax oil and the diesel oil enter a second reaction zone (zone II) of the two-section riser together, and the oil slurry enters a vacuum distillation tower; (3) a lower-carbon-residue light-distillate material of an upper-part outlet of the vacuum distillation tower and a higher-carbon-residue heavy-distillate material of a middle-part outlet of the vacuum distillation tower enter a hydrogenation device together, and ultrahigh-carbon-residue oil slurry at the bottom of the vacuum distillation tower 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 gasoline 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 gasoline. 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 e...

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Problems solved by technology

[0008] The above-mentioned patent uses a combined hydrogenation and catalytic cracking process or a two-stage catalytic cracking process to treat the oil slurry at the bottom of the catalytic cracking fractionation tower, which can increase the yield of gasoline or diesel oil or light olefins to a certain extent. But it does not have the effect of simultaneously increasing the yield of gasoline and low-carbon olefins

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