Abstract: A power plant with efficient emission control and high turbine inlet temperatures is disclosed. The power plant includes a combustor for the combustion of carbonaceous sulfur-bearing fuel. The combustion of this fuel produces a hot gas with SO.sub.x and NO.sub.x contaminants. This gas is conveyed to a refractory heat exchanger where some of the heat from the gas is transferred to a pressurized air stream. The gas is then conveyed to a fluidized bed reactor. The fluidized bed reactor includes a central chamber with a fluidized bed positioned at the base of the chamber. Heat exchangers are positioned within the fluidized bed. These heat exchangers preheat the pressurized air stream which is then conveyed to the refractory heat exchanger and later conveyed to a turbine assembly. The fluidized bed reactor also includes circulating particulate matter, such as CaO. Ammonia may also be injected into the fluidized bed reactor. When operating at a temperature of at least 1,500.degree. F.

Abstract: A method of controlling the solids circulation between a downflow reactor and an entrained bed reactor is disclosed wherein at least some of the solids are transferred from the downflow reactor to a crossflow fluidized bed through a first seal leg, wherein the crossflow fluidized bed has a baffle separating the crossflow fluidized bed into two zones. Then the solids are transferred from the crossflow fluidized bed to the entrained bed reactor, and the solids are transferred from the entrained bed reactor to the downflow reactor through a second seal leg. The solids circulation rate is controlled by adjusting the rate of fluidizing gas entering the crossflow fluidized bed.

Abstract: A carbonaceous material, such as coal, is gasified in a vertically elongated reaction vessel having a lower portion, an upper portion, and a re-entrainment zone which is located above the upper portion. The effective diameter of the upper portion of the vessel is larger than that of the lower portion of the vessel and the re-entrainment zone. A gasification agent is passed upwardly through the vessel at a rate sufficient to entrain the coal and fluidize a heat-transfer material in the lower portion of the vessel. The gasification agent reacts with the coal to form a hot char and a gaseous product, with the necessary heat being supplied by the heat-transfer material. In this process, the heat-transfer material substantially flows downwardly in the reaction vessel, in a fluidized state or an unfluidized state through the upper portion of the vessel and in a fluidized state through the lower portion of the vessel.