Abstract: A method and apparatus for combustion of a solid carbonaceous material in which the solid carbonaceous material is preheated and at least a portion thereof pyrolyzed on a stoker grate disposed in the lower portion of a combustion chamber to produce pyrolysis products. Overfire oxidant is then introduced into the combustion chamber above the stoker grate to ensure complete combustion of combustibles in the products of combustion generated by combustion of the solid carbonaceous material and the pyrolysis products. Preheating and pyrolysis of the solid carbonaceous material is carried out by the introduction of a pyrolysis agent directly into the bed of solid carbonaceous material.

Abstract: A multi-stage heating apparatus having a first stage combustion chamber, a second stage combustion chamber, a primary porous matrix chamber disposed between the first and second stage combustion chambers, a secondary porous matrix chamber, heat exchanger tubes for transfer of heat from the combustion products to a working fluid, a recirculation device for recirculating combustion products in the first and second stage combustion chambers to the root of flames therein. A mixture of fuel and primary oxidant is introduced into the first stage combustion chamber, and the products of combustion therein are conveyed to the porous matrix chamber disposed between the first and second stage combustion chambers. After undergoing intensive heat transfer in the porous matrix chamber, the cooler products of combustion flow into the second stage combustion chamber forming additional products of combustion.

Abstract: A method and apparatus for low-NOx combustion of a pulverized solid fuel in which combustion products from a partial oxidation combustor are mixed with a pulverized solid fuel, thereby preheating the pulverized solid fuel and resulting in devolatilization of at least a portion of the pulverized solid fuel. The preheated pulverized solid fuel and the devolatilization products are then burned in a burner firing directly into a combustion chamber.

Abstract: A process and apparatus for combustion in which a combustible material is introduced into a combustion chamber and oxidant is supplied to the combustion chamber. The combustible material is burned, and forming a primary combustion zone. A mixture of flue gases and flyash having an organic content is injected into the combustion chamber downstream of the primary combustion zone to create an oxygen-deficient reburn zone, thereby lowering the temperature of combustion, reducing the NO.sub.x content of the flue gases, and reducing the potential for NO.sub.x formation in a tertiary oxidizing combustion zone disposed downstream of the oxygen-deficient reburn zone.

Abstract: A process for combustion of a combustible material in which a primary combustible material is introduced into a combustion chamber having an upstream region and a downstream region, and ignited, forming a primary combustion zone. A secondary combustible material is partially combusted in a partial combustor, forming partial combustion products which are then injected into the combustion chamber downstream of the primary combustion zone, forming an oxygen deficient zone downstream of the primary combustion zone.