A device for removing propylene in dry gas and a method for removing propylene in dry gas

Abstract

The invention provides a method for removing propylene in dry gas. The method includes steps of washing the catalytic dry gas by a water wash tower; pressurizing the catalytic dry gas by the aid of a dry gas compressor; buffering the catalytic dry gas by a buffer tank and absorbing the catalytic dry gas by absorbents in a propylene absorption tower to obtain tower top purified dry gas and absorption tower bottom liquid; treating the absorption tower bottom liquid by the aid of an ethylene removal tower to obtain ethylene-rich dry gas and ethylene removal tower bottom liquid; treating the ethylene removal tower bottom liquid by the aid of a propylene removal tower to obtain propylene-rich dry gas. The absorbents comprise benzene and diethylbenzene. The method has the advantages that steps of washing, pressurizing, buffering, absorbing and the like are carried out on the catalytic dry gas, accordingly, the dry gas at an ultimate outlet is low in propylene content, and the propylene can be deeply removed; the ethylene-rich dry gas and the propylene-rich dry gas can be obtained by the aid of the method and further can be applied to downstream production.

Description

technical field [0001] The invention relates to the field of environmental technology, in particular to a device for removing propylene in dry gas and a method for removing propylene in dry gas. Background technique [0002] The content of propylene in raw dry gas is mostly above 0.7%, and the presence of high content of propylene will seriously affect the selectivity of the alkylation reaction and the service life of the catalyst. [0003] At present, most refineries use a device that absorbs C3 and above in dry gas twice, specifically: the naphtha extracted from the fractionation tower is used as an absorbent, and then diesel oil is used as a reabsorbent to absorb the naphtha carried in the dry gas components. The main scheme used is: crude gasoline enters the first absorption tower to absorb propylene and above components in the dry gas component, a large amount of crude gasoline is carried in the gas phase at the top of the tower, and the gas phase at the top of the tow...

AI Technical Summary

Problems solved by technology

At the same time, the absorption effect of this method is greatly affected by the absorbent components, and the general effect after absorption is not good, resulting in the inclusion of propylene in the dry gas

Consequences: 1. High value-added chemical products with high propylene number, high price, mixed in dry gas, and serious waste; currently, stable gasoline is used as absorbent and diesel oil is used as reabsorbent, due to the existence of absorbent itself and absorbed substances The overlapping of components leads to the content of C3 and above in the dry gas after absorption is more than 1.5%, especially the high value-added components in the dry gas: the content of propylene is more than 0.5%, which not only causes the waste of overlapping components, And it also affects the use of subsequent dry gas

2. The existence of propylene and the above components in dry gas affects the reuse of dry gas, such as dry gas production of ethylbenzene, dry gas separation, etc.

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