Abstract: Method and apparatus for controlling the distribution of secondary air (30) between at least two fuel burners (14,16) in a multiple fuel combustor (16). Total chemical energies of the individual fuel streams (44,60) are determined and compared (64,66) with the total combustor chemical energy input (62) for controlling biasing means (32,34). The determination of at least one individual fuel total chemical energy content (60) may optionally include a prompt neutron activation type analyzer (48) for on-line measurement of specific fuel chemical energy (59).

Abstract: A method and apparatus for the operation of a stoker-fired boiler having a boiler arranged coaxially adjacent to a stoker chamber. The cross-sectional area of the connection between the stoker and the boiler is constricted, preferably in the range of one-third to one-fourth of the cross-sectional area of the stoker chamber, so that the flammable gases flowing from the stoker to the boiler are accelerated and generate a reduced pressure at the constricted connection. Tertiary air is introduced at the circumference of the constricted connection at an increased pressure, to thereby induce more complete combustion of the gases. The area of flow flares out as the gas enters the boiler. In the preferred arrangement, guide means control the introduction of the tertiary air through an annular gap at the constricted connection The stoker also preferably includes rings of nozzles arranged at selected angles to introduce secondary air into the stoker chamber.

Abstract: A continuous process for the combustion of solid fuels under conditions such that flue gas is essentially free of particulates and oxides of sulfur and nitrogen. Fuel is charged as an aqueous slurry and additional water condensed from the flue gas may be recycled to the pressurized combustion zone. Combustion is promoted both by water vapor and alkali added with the fuel slurry, while the alkali serves also to neutralize and remove sulfur in completely oxidized, or sulfate, form. Heat of combustion raises the temperature of the reactants above the critical temperature of water, forming a hot fluid from which useful heat is transferred. Under the pressure of the system, heat recovery results in condensation of water, retaining and slurry product ash and providing recycle water, which helps to control reaction temperature as well as to promote the combustion.

Abstract: A cross fire stoker adapted to burn a difficultly ignited fuel is disclosed, together with a method of operating the stoker. The stoker is adapted to burn such fuel in a furnace not having large front or rear arches and includes a horizontal traveling grate within the furnace which is adapted to convey a bed of solid carbonaceous fuel from a charging zone, through an ignition zone, through a firing zone, and to an ash discharging zone. A suction fan is provided at the initial windbox to downdraft an oxygen-containing fuel to the bed at an ignition zone closely adjacent said charging zone. The remainder of the bed is subjected to updrafting for firing the bed to reduce it to ash.

Abstract: In order to burn a fuel of low ignition properties and low contents of volatile gases in steam generators: the combustion air is introduced in three batches at three successive places into the firebox. Preferably, the primary air is introduced at a temperature of at least about 500.degree., preferably between 500.degree. and 600.degree. C. so as to effect a pregasification of the fuel. The secondary air is then introduced at a temperature of about 350.degree. to 400.degree. C. to start the combustion of the pregasified fuel and the tertiary air is finally introduced at a temperature of only about 250.degree. to 300.degree. C. in order to complete the combustion. This temperature differentiation of heat ranges then will permit to withdraw theash as a dry discharge.

Abstract: A reactor wherein a biomass is moved progressively downwardly along the upwardly facing side of an inclined grate supported with an enclosure comprising a retort, the rear and front walls of which provide, in conjunction with the grate, a plenum chamber at the downwardly facing side of the grate and a mixing chamber at the upwardly facing side of the grate, the said structure providing for converting the biomass by a process of destructive distillation to CO and ash characterized in that the grate is maintained at a temperature below the fusion temperature of the ash to prevent slagging of the ash by the expedient of supplying an excess of primary air to the plenum chamber at the lower end of the grate so that it flows upwardly along the downwardly facing side thereof, the surplus discharged at the top, providing the grate with a plurality of relatively small openings distributed throughout its length and breadth and providing fins at the downwardly facing side of the grate perpendicular to the plane of the u