The objectives of the project were to investigate coal-char gasification reactions with CO/sub 2/, H/sub 2/O and other gases, to examine fluid dynamics of char present in a fluidized bed, and to develop a computer model of the fluid-bed gasification which can incorporate such information. To these ends a unique high pressure/temperature thermogravimetric analysis instrument, a pressurized 30 cm-dia. fluid bed, and a high-temperature 13 cm fluid bed were constructed. Coal pyrolysis and char reactions were examined at temperatures to 1600/sup 0/C and pressure to 28 atm. Extent of pyrolysis was shown to depend on particle size and pressure, and in three stages on temperature. Char properties were determined, including diffusion coefficients of CO/sub 2/ in char and surface areas. Char reactivity does not strongly depend on pressure in the range 1 to 28 atm. Diffusion limits are strongly present above 1000/sup 0/C. Inhibition by CO and H/sub 2/ increase rapidly with pressure. Elutriation of particles in a hot bed can be determined from low-temperature results if compared at the same value of excess fluid velocity above minimum fluidization. Bubble size and numbers change slightly with pressure. Fluid bed gasification can be modeled successfully, and a basic model is presented here.