Three-tower device and method for recycling ethylene and ethane from dry gas through oil absorption

Abstract

The invention relates to a three-tower device and method for recycling ethylene and ethane from dry gas through oil absorption. The method comprises the following steps: pressurizing and cooling the dry gas through a compressor, mixing the dry gas with rich liquid from an absorption tower and desorbed gas from a desorption tower, enabling the mixture to enter a heat exchanger for cooling so as to enable the temperature of the mixture to reach absorbent temperature; enabling the mixture to enter a flash drum for single flash, and enabling a gas phase used as a gas phase feeding material of the absorption tower to enter from the tower bottom; enabling a liquid phase used as a feeding material of the desorption tower to enter from the tower top; refining products at the bottom of the desorption tower through a rectifying tower so as to obtain the products of ethylene and ethane; enabling the products at the bottom of the rectifying tower to be supplemented and cooled, and then returned to the rectifying tower top to be used as an absorbent. An intercondenser is arranged in the absorption tower, so that heat generated can be absorbed timely. According to the invention, the contents of methane and other light components are adjusted through the desorption tower, the content of the methane is 0.05% lower than that of the ethylene and polymer grade ethylene can be obtained directly from an ethylene tower. The method provided by the invention is suitable for separating and recycling C2 component from catalytic cracking dry gas and has the high potential of replacing a deep-cooling method.

Description

technical field [0001] The present invention relates to catalytic cracking dry gas separation process, especially relates to oil absorption process to recover ethylene, ethane equipment and method, its main feature is that the product can directly enter the deethanizer tower to obtain polymer grade ethylene. belongs to chemical technology. Background technique [0002] Catalytic cracking dry gas is a large amount of gas produced in the process of petroleum refining, and its main components include hydrogen, nitrogen, oxygen, methane, ethylene, ethane, etc. In most cases, due to the lack of dry gas recovery means, the dry gas is directly burned as fuel gas. This is a great waste of valuable gases represented by ethylene and ethane. At the same time, with the continuous development of catalytic cracking processes that produce more olefins, the amount of dry gas and its ethylene content are increasing. Therefore, it is very important to recover dry gas, especially the ethyle...

AI Technical Summary

Problems solved by technology

The methane content in the products obtained by the current absorption method is relatively high, and the product gas needs to be separated into the pyrolysis gas cryogenic separation system to obtain polymer grade ethylene, which greatly limits the application range of the absorption method

For companies without cryogenic demethanizers, the investment to obtain polymer grade ethylene becomes very large

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