High-temperature high-pressure sulfur removal is considered to be one of the key steps in the hot gas cleanup train of an integrated gasification combined cycle (IGCC) process. Regenerable mixed metal oxide sorbents such as zinc titanates are prime candidates for this purpose. As part of sulfur removal process development, Carbona Corp. is developing fluidized bed reactor models for scale-up. In the first part of this work, the parameters for the unreacted shrinking core and overlapping grain models were determined to describe the rate of zinc titanate in H2S capture. A method using these sorbent particle conversion models for fluidized bed application is presented in this paper. Both models show a reasonably good fit to the high-pressure fluidized bed sulfidation test data, with the same order of magnitude parameters as obtained in the previously reported solid conversion rate tests.