OPERATION AND MODELING OF A PILOT-SCALE FLUIDIZED BED COAL GASIFIER (KENTUCKY, NEW MEXICO, NORTH CAROLINA, TEXAS, PEAT, LIGNITE)

A devolatilized Kentucky bituminous coal, a New Mexico subbituminous coal, a North Carolina peat, and a Texas lignite were gasified with steam and oxygen in a pilot-scale fluidized bed reactor. The reactor was operated at pressures of 570-840 kPa (80-120 psia), molar H(,2)O/C feed ratios of 0.6 to 1.9, and average bed temperatures of 795-1010(DEGREES)C (1460-1850(DEGREES)F). The coal feed rate ranged from 14 to 33 kg/hr (30-73 lb/hr). All reactor effluent streams were measured and analyzed, enabling performance of mass and energy balances and identification of potentially hazardous species.; Two main reactor models were developed to simulate the gasification reactor--a simple well-mixed model, and a two-phase bubbling bed model. The simple model assumes instantaneous devolatilization and combustion, and steam/carbon gasification and water gas shift reaction in a single perfectly mixed stage. The two-phase model takes the hydrodynamics of a fluidized bed into consideration, as it assumes the fluidized bed to consist of an incipiently fluidized emulsion phase and a solids-free bubble phase.; Both models were used to correlate data for the gasification of the Kentucky char and the New Mexico coal. In general, the agreement between model predictions and experimentally measured variables was excellent.