Absorption and hydration coupling device and method for separating ethylene and ethane in catalytic cracking dry gas or ethylene pyrolysis gas

Abstract

The invention provides an absorption and hydration coupling device and a method for separating ethylene and ethane in catalytic cracking dry gas or ethylene pyrolysis gas. The method is divided into two processes: the catalytic dry gas or the ethylene pyrolysis gas enters an absorption separation process; a high-purity C2 product is obtained through absorption, desorption and absorbent regeneration; C2 lean gas at the top of an absorption tower enters a hydration separation process; and then C2 gas recovered in hydration separation and virgin gas are merged and return to the absorption separation process. The absorption separation process and the hydrate separation process are combined; the advantages that the separation efficiency of an absorption method in a high concentration area is high, and the separation efficiency of a hydration separation method in a low concentration area is high are exerted; the solvent amount required by the absorption process is reduced; the defects that the hydration separation purity is not high and the separation efficiency is low are avoided; the purity of the obtained C2 product can reach 99.6%; and the C2 product can directly enter an ethylene tower. The method is suitable for separating the recovered C2 from the catalytic cracking dry gas or the ethylene pyrolysis gas, and is hopeful for substituting a cryogenic separation technology.

Description

Technical field [0001] The invention relates to a combined device and method for separating and recovering ethylene and ethane in catalytic dry gas or ethylene cracking gas by combining an absorption separation process and a hydration separation process, and belongs to chemical technology. Background technique [0002] As the core of oil refining technology, catalytic cracking plays an important role in the deep processing of crude oil, and it is also one of the biggest benefit devices of oil refining enterprises. The liquefied gas produced by the catalytic cracking unit is recycled through the gas separation unit to recover propylene, which has also brought very good benefits to many oil refineries. However, the dry gas, which is a by-product of the catalytic device, has not been paid much attention to at present and is usually used as a fuel. However, the catalytic dry gas contains higher value-added ethylene, if it can be properly recovered, it will be another bright spot for...

AI Technical Summary

Problems solved by technology

The traditional absorption separation method achieves separation through the difference in the distribution coefficient of the gas in the gas-liquid two-phase, but in practical applications, when the concentration of C2 in the gas phase is low, due to the influence of the equilibrium relationship, it is necessary to use a large amount of absorbent, so low concentration Separation doesn't make sense

Images