Dry gas recovery system and dry gas recovery method for refinery plant

Abstract

The invention discloses a dry gas recovery system and method for a refinery plant. The system comprises a compressor, an absorption tower, a stripping tower, an expansion machine-cold box system and a liquefying cooler, wherein the compressor is connected with the absorption tower; the bottom of the absorption tower is connected with the stripping tower; the bottom of the stripping tower is connected with the upper part of the absorption tower; the top of the stripping tower is connected with the liquefying cooler; the top part of the absorption tower is connected with the expansion machine-cold box system; the expansion machine-cold box system comprises a cold box, an expansion machine, a supercharger and a flash tank; the top part of the absorption tower is connected with the cold box; the cold box is sequentially connected with the expansion machine and the flash tank; and the top part of the flash tank is connected with the cold box, and is connected with the supercharger. The method comprises the steps of compressing, cooling, absorbing, stripping and liquefying dry gas of the refinery plant to obtain carbon 2-enriched products. The method has the advantages of few equipment, low energy consumption, simple flow and high recovery rate, and the product is easy to store and transport.

Description

technical field [0001] The invention relates to the field of dry gas treatment in refineries, and more specifically, to a dry gas recovery system and a dry gas recovery method. Background technique [0002] Refinery dry gas mainly comes from the secondary processing of crude oil, such as catalytic cracking, thermal cracking, delayed coking, hydrocracking, etc. Generally, the content of ethylene in catalytic dry gas is relatively high, while the content of ethane in coking dry gas is relatively high, about 15% to 25%. In addition, refinery dry gas also contains alkenes such as propylene, propane and butane. At present, most refineries in my country still burn the refinery dry gas as fuel gas, which has low utilization value and causes great waste of resources and environmental pollution. [0003] Ethane is an ideal raw material for cracking, and a considerable part of it is converted into ethylene during steam cracking. If the ethane in the refinery dry gas is recovered and...

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Problems solved by technology

[0011] In order to solve the problems of large investment, high energy consumption, and limited process applicability in the existing refinery dry gas recycling process in the prior art, the present invention provides a refinery dry gas recovery system and a dry gas recovery method

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