The report gives results of gasifying four fuels--a devolatilized Kentucky bituminous coal, a New Mexico subbituminous coal, a North Carolina peat, and a Texas lignite--with steam and oxygen in a pilot-scale fluidized-bed reactor. Experimental results were used to provide an evaluation of mathematical models developed for the gasifier. A simple three-stage gasifier model and a two-phase bubbling-bed model were developed. Model options include allowance for a jetting region at the gas inlet of the bed and elutriation of fines. Gasification reactions in both models are described by Johnson kinetics. The models were applied to the gasification of the devolatilized Kentucky bituminous coal and the New Mexico subbituminous coal. Parameter optimizations were performed with each model for each feedstock. The main difference in the optimal values was in char reactivity, for which that of the New Mexico coal was roughly an order of magnitude greater than that for the Kentucky char. Using the optimal values, the models were applied to all experimental runs with these two coals. The resulting model predictions and experimental results showed reasonably good agreement in all cases.