Evaluation of Sorbents for High Temperature In Situ Desulfurization of Biomass-Derived Syngas

In a preparative study, the use of different sorbent materials for in situ desulfurization of biomass derived synthesis gas is evaluated. Results of phase equilibrium calculations using FactSage version 6.4 for the H2S equilibrium concentration with a variation of different parameters are compared to values for the residual H2S content found in literature. The focus is strictly set on a high temperature, high steam application for biomass-derived syngas conditions. Possible synergistic effects between different sorbent components and deviations from simulated results are discussed subsequently. The use of copper-based sorbent material turns out to be promising due to a predicted positive impact of high steam conditions for sorption equilibria. Results for the implementation of a CaO–BaO mixed phase sorbent are confirmed, qualifying this material combination as a promising candidate for in situ application. Equilibrium calculations predict a desulfurization of syngas to a sulfur level of 2.1 ppmv H2S at a steam content of about 40 vol % and 820 °C which is sufficient for further catalytic gas processing applications.