A reaction rate of a zinc titanate sorbent with H₂S for scale-up design was obtained from a simplified semi-batch fluidized reaction model and experimental data from a hot gas desulfurization fluidized bed reactor at high pressure condition. The global reaction rate from a fluidized bed reactor of 7.5 cm inside diameter was 1,276 cm³ gas/gmole H₂S/sec, which is 5 times smaller than that from TGA. The global reaction rate can be used in the design for the scale-up because the reaction rate includes the effects in fluidized bed such as bubble charateristics, mass transfer, entrainments, and solid mixing etc. Sensitivity of parameters on a fluidized reactor performance was analyzed with the simplified model.