Method for separating refinery catalytic dry gas by adopting oil absorption

Abstract

The invention discloses a method for separating refinery catalytic dry gas by adopting oil absorption. The method comprises the following steps: using a C4 fraction as an absorbent, keeping the absorption temperature at 5 to 15 DEG C, and recycling the refrigeration capacity by adopting an expander and a cold box. Through the method of the invention, the recovery rates of olefin and alkane are greatly improved, and meanwhile, the circulating quantity and the loss quantity of the absorbent are reduced, the energy consumption is reduced, and the problems of large investment and high energy consumption in the existing traditional process for recycling the olefin and the alkane from refinery dry gas are solved.

Description

A method for separating refinery catalytic dry gas by oil absorption technical field The invention relates to a method for separating catalytic dry gas of a refinery, in particular to a method for separating and recovering olefins and alkanes in the catalytic dry gas of a refinery by absorbing carbon four fractions. Background technique Catalytic dry gas in refinery comes from catalytic cracking process. Usually, the content of ethylene in the dry gas is about 12-20 mol%, the content of ethane is about 15-24 mol%, and it also contains alkenes and alkanes such as propylene, propane and butane. At present, catalytic dry gas in refineries is mainly burned as fuel, and its utilization value is low. If the olefins and alkanes in the catalytic dry gas are recovered and sent to the ethylene plant as the raw material for ethylene production, a large amount of cracked raw material oil can be saved, the cost of ethylene production can be greatly reduced, and the enterprise can obtai...

AI Technical Summary

Problems solved by technology

In order to solve the problems of large investment and high energy consumption in the existing technology for recovering ethylene and propylene from refinery dry gas, the present invention proposes a highly efficient method for separating refinery catalytic dry gas by using the oil absorption method. The four fractions are used as absorbent to recover ethylene and propylene, keep the absorption temperature above 5 degrees, use expander and cold box to recover cooling capacity, no ethylene refrigerator is needed, and investment and energy consumption are reduced

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