Process for the manufacture of an attrition resistant sorbent used for gas desulfurization

This process of manufacture results in an attrition resistant sorbent for use in gas desulfurization processes. In the process of desulfurization of coal gases, mixed metal oxides have been used to remove hydrogen sulfide (H S) in the temperature range of 370 to 650° C. (700 to 1200° F.). Although the reactivities of zinc titanates and other zinc based sorbents are acceptable in this temperature range, the physical and mechanical integrity of the sorbents needs to be improved so that the sorbents can be used over repetitive cycles of sulfur absorption and sorbent regeneration. For moving-bed reactor configurations, the mixed metal sorbents are prepared from powders which are extruded into pellets and calcined to achieve a balance point of desired reactivity and pellet strength as measured by attrition and crush strength tests. Unfortunately, this balance between reactivity and pellet strength is difficult to achieve and many highly reactive pellets become mechanically weak and fall apart after several cycles due to repetitive phase transformations that occur during repeated cycles of absorption and regeneration. During sulfur removal, zinc-based oxides become zinc sulfide as shown in Equation 1. This process produces a sorbent for use in desulfurization of coal gas. A zinc titanate compound and a metal oxide are mixed by milling the compounds in an aqueous medium, the resulting mixture is dried and then calcined, crushed, sleved and formed into pellets for use in a moving-bed reactor. Metal oxides suitable for use as an additive in this process include: magnesium oxide, magnesium oxide plus molybdenum oxide, calcium oxide, yttrium oxide, hafnium oxide, zirconium oxide, cupric oxide, and tin oxide. The resulting sorbent has a percentage of the original zinc or titanium ions substituted for the oxide metal of the chosen additive.