A high capacity manganese-based sorbent for regenerative high temperature desulfurization with direct sulfur production conceptual process application to coal gas cleaning

A high capacity, monolith or particle shaped, regenerable sorbent has been developed for the desulfurization of a dry type coal gas. It consists of crystalline MnAl2O4, a small amount of disperse MnO, and an amorphous Mn-Al-O phase. Elemental sulfur is the only observed regeneration product during regeneration with SO2. The sorbent can be used in the temperature range between 673 and 1273 K but the optimum capacity is utilized between 1100 and 1200 K. For regeneration with SO2 the regeneration temperature should be >873 K to avoid sulfate formation. The sulfur uptake capacity is high and amounts up to 20 wt.% S and the sorbent performance appears to be stable during at least 110 sulfiding and regeneration cycles at 1123 K. For temperatures above HOOK thermodynamic calculations are in accordance with the observed (solid) phases after sulfiding and regeneration, indicating the predictive potential for high temperatures. The performance of the surface sites that play an important role during desulfurization can, however, not be predicted. The regenerative removal of H2S, COS, HCl and HF can possibly take place simultaneously with the same sorbent. A new conceptual process configuration for high temperature coal gas cleaning and sorbent regeneration is proposed. Compared to other processes, less heat exchange equipment is required and no Claus unit is necessary to convert the regeneration product to sulfur. (C) 2003 Elsevier B.V. All rights reserved.