Desulfurization / tar removal for gasifier and biogasifier effluents with mixed rare earth oxides

Document Type

Conference Proceeding

Publication Date

12-1-2008

Abstract

Current materials for high temperature H2S removal from gasifier effluents are Zn- and Ca-based sorbents. These work at temperatures less than typical gasifier (especially biogasifier) effluent temperatures. We are examining sorbents based on Ce/La/M (M = transition metal) oxides and Ce/La/RE (RE = a rare earth) oxide. Reduced Ce/La oxides adsorb H2S at temperatures of 600°C and above, and are regenerable in O2 mixtures. But addition of group VII-VIII transition metals to Ce/LaOx increases the sulfur removal capacity significantly. Addition of oxides such as ZrO 2 or a third rare earth oxide increases surface area, sintering resistance of CeOx/La2O3 at high temperatures, and sulfur capacity. These sorbents can be regenerated at temperatures near the operating conditions of gasifiers. They can also be used as tar cracking catalysts for tars formed in the gasifier. The results of some characterization tests, including H2S adsorption / TPD, are presented.

Publication Source (Journal or Book title)

AIChE Annual Meeting, Conference Proceedings

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