Method for removing impurities in catalytic dry gas

Abstract

The invention discloses a method for removing impurities in catalytic dry gas, the method comprises five steps of dry gas pretreatment, cold oil absorption, desorption, cold separation and reduction, after the dry gas is subjected to deacidification treatment and secondary compression, the temperature and pressure of dry gas pretreatment are controlled, acidic substances, smoke and dust in the catalytic dry gas are removed, and the volume of the dry gas is compressed; light hydrocarbon is absorbed and recovered by cold oil, C2, C3 and other components are separated by cold separation, and unabsorbed components mainly comprising methane are recovered by reduction and deoxidation, so that the recovery of crude ethylene and crude methane is achieved; oxidizing gas existing in the dry gas is removed through the reduction step, methane with higher concentration is obtained, and stable storage conditions are provided for the methane.

Description

technical field [0001] The present application relates to the field of process recovery, in particular to a method for removing impurities from catalytic dry gas. Background technique [0002] Catalytic cracking and catalytic cracking are important petroleum processing processes. The waste gas (catalytic cracking dry gas and catalytic cracking dry gas, etc., collectively referred to as catalytic dry gas) produced by these processes exceeds 5.5 million tons / year, of which about 1 million tons of ethylene are contained. / year, in addition to H 2 ,CH 4 ,C 2 H 6 ,C 3 H 6 ,CO,CO 2 ,H 2 O and H 2 S and other components. Due to the shortage of pure ethylene resources, there are many studies on the recovery and direct conversion of ethylene, and there are also a few studies on hydrogen recovery. [0003] In fact, the typical composition in the catalytic dry gas is shown in Table 1 below. The volume fraction of hydrogen is too large, but the mass fraction is very low, which...

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Problems solved by technology

[0003] In fact, the typical composition of catalytic dry gas is shown in Table 1 below. The volume fraction of hydrogen is too large, but the mass fraction is very low, which brings unnecessary space and time costs to the recovery of catalytic dry gas. In addition, people often Ignoring the high content of methane components in the catalytic dry gas, directly discharging or removing them, resulting in a waste of resources, polluting the environment, and leading to the aggravation of the greenhouse effect, and the full utilization of the catalytic dry gas cannot be achieved.

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