A method for separating diesel fraction from light raw oil

Abstract

The invention belongs to the field of petroleum processing, and especially relates to a method used for separating diesel oil cut fractions from light raw oil. According to the method, light raw oil rich in diesel oil cut fractions is mixed with high temperature reaction oil gas directly; an obtained mixture is delivered into a main fractionating tower desuperheating section, and separation of diesel oil cut fractions and wax oil cut fractions is realized under the effect of surplus heat; diesel oil cut fractions are delivered into a product tank via a main fractionating tower diesel oil outlet; wax oil cut fractions are delivered back into a lift pipe via a recycle oil outlet, so that catalytic cracking of the diesel oil cut fractions is avoided, dry gas and coke yield is reduced, the ratio of conversion of hydrocarbon molecules into aromatic hydrocarbon molecules in diesel oil is reduced, the quality of catalytic diesel products is improved. Catalytic processing capacity is reduced, and coke yield is reduced, so that device energy consumption is reduced, and the method is suitable for old device modification and new device design.

Description

technical field [0001] The invention belongs to the field of petroleum processing, and in particular relates to a process method for separating light raw material oil by using a main fractionation tower of a catalytic cracking unit to remove the superheating section so as to avoid repeated processing of the diesel fraction. Background technique [0002] Catalytic cracking is an important secondary processing device for crude oil. It converts heavy distillate oil into liquefied gas, gasoline, diesel, etc. under the action of catalysts through reactions such as decomposition, isomerization, hydrogen transfer, aromatization, and condensation. Light distillate oil, and a certain amount of dry gas, oil slurry and coke are produced by-product. The 10% point of the distillation range of the heavy feedstock oil is higher than 350°C, the 10% point of the distillation range of the light feedstock oil is lower than 340°C, and the 30% point of the distillation range of the light feedsto...

AI Technical Summary

Problems solved by technology

[0005] In order to solve the problem that in the feed of the riser reactor of the existing catalytic cracking unit, part of the diesel fraction contained in the light feedstock oil is forced to undergo catalytic cracking reaction, which not only increases the processing capacity of the unit, but also increases the yield of coke and dry gas and deteriorates the quality of diesel oil Due to the disadvantages of the main fractionation tower of the catalytic cracking unit, a process for separating light feedstock oil from the superheated section and avoiding repeated processing of the diesel fraction is proposed.

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