Effective reclamation of vent gas in ethylbenzene dehydrogenation by coupling multi-stage circle absorption and membrane units

CATEGORY: DEHYDROGENATION
Effective reclamation of vent gas in ethylbenzene dehydrogenation by coupling multi-stage circle absorption and membrane units

Type	Journal Article
Author	Xuehua Ruan
Author	Lijuan Wang
URL	http://www.sciencedirect.com/science/article/pii/S1383586616305901
Volume	168
Pages	265-274
Publication	Separation and Purification Technology
Date	August 10, 2016
Abstract	Ethylbenzene catalytic dehydrogenation produces large amounts of hydrogen. Its vent gas is attractive with hydrogen content higher than 75 mol%. However, styrene remaining in the vent gas is highly active to polymerize into oligomers, the gradual accumulation of which is harmful to hydrogen separation equipment. Authors describe an integral separation process including absorption and membrane units to overcome this challenge. They propose an absorption unit running with fresh ethylbenzene as the absorbent to remove styrene, the residual content of which is reduced to less than 10 ppm. The generation and accumulation of styrene oligomers is restrained to protect hydrogen separation equipment. In addition, the custom-designed absorption tower with a multi-stage cycle structure is used to improve styrene content in the used ethylbenzene at tower bottom, in order to reduce styrene recovery expense.