Refinery mixed dry gas recovery system and recovery method

Abstract

The invention discloses a refinery mixed dry gas recovery system and a recovery method. The system comprises an absorption tower, a desorption tower, a rough separation tower, a purification device, a gasoline absorption tower and a gasoline desorption tower, wherein a compressor is connected with a heat exchanger and then is connected with the absorption tower, the top of the absorption tower is connected with the gasoline absorption tower, and the bottom of the absorption tower is connected with the desorption tower; the top of the desorption tower is connected with the purification device and then is connected with the rough separation tower, the bottom of the gasoline absorption tower is connected with the gasoline desorption tower, the top of the gasoline desorption tower is connected with the upper part of the absorption tower, and the bottom of the gasoline desorption tower is connected with the upper part of the gasoline absorption tower. According to the recovery system, a C2 component is recovered from dry gas through one set of absorption-desorption, a tower top gas phase of the desorption tower enters the rough separation tower, and an entrained absorbent is recovered through another set of absorption-desorption; ethylene-rich gas is recovered from the tower top of the rough separation tower and is delivered to an ethylene unit demethanizer, and ethane-rich gas is recovered from a reactor of the rough separation tower and is delivered to an ethylene unit cracking furnace. According to the recovery method disclosed by the invention, the flow is simple, the recovery rate is high, saturated hydrocarbons and unsaturated hydrocarbons are treated separately, and the operation of an ethylene unit is hardly affected.

Description

technical field [0001] The invention relates to the field of dry gas treatment, and more specifically relates to a refinery dry gas recovery system and 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. 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] Generally, the content of ethylene in catalytic dry gas is high, which belongs to unsaturated dry gas. Saturated dry gas usually comes from PSA desorption gas, light hydrocarbon dry gas, hydrogenation dry gas, reforming dry gas, etc. Ethane and propane in saturated dry gas The content is relatively high, while the content of ethylene and propylene is very low. Therefore, the composition and application of enriched gas after recovery of...

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Problems solved by technology

[0014] In order to solve the problems of how to centrally recover and utilize saturated dry gas and unsaturated dry gas, as well as existing processes such as large investment, high energy consumption, low recovery rate, and limited process applicability, the invention provides a refinery mixing Dry gas recovery system and method

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