A detailed comparison between agglomerated pellets of limestone and commercial-grade plaster of Paris was conducted to test the reactivity of the pellets with H2S over three cycles of sulfidation and regeneration. After multicycle testing with 1 vol % H2S at 880 °C, it was determined that the higher surface area exhibited by the plaster of Paris pellets provided a consistently higher reactivity than the limestone pellets. The effects of pore-forming additives on agglomerated limestone pellets was tested with starch, graphite, and poly(vinyl alcohol) (PVA). The results indicated that the PVA−limestone pellets exhibited a higher capacity for sulfur than plain limestone pellets over multiple cycles. A comparison between pellets made of two different grades of plaster of Paris, limestone, calcium carbonate, dolomite, and hydrated dolomite over three cycles of sulfidation and regeneration provided results indicating that plaster of Paris and hydrated dolomite exhibited the best reactivity and thermal stability. The plaster of Paris and hydrated dolomite also exhibited a capacity for H2S over eight cycles of sulfidation and regeneration that proved promising for possible application in IGCC systems.