Abstract: A pulverized solid fuel is injected into a shaft furnace by being entrained in a stream of pressurized air, the resulting fuel-air mixture subsequently being further mixed with heated air being delivered to the furnace via a tuyere. The air used to entrain the pulverized fuel is diverted from the cold air supply to a mixing station, which is used to control the temperature of the hot air supplied to the furnace via the tuyere, and this diverted air is pressurized prior to the pulverized material entrainment.
Abstract: A furnace in which fuel, such as pulverized coal, is burned, with the fuel and air being introduced into the furnace through tangential burners located in each of the four corners thereof and being directed tangentially to an imaginary circle in the center of the furnace. The invention will be described with pulverized coal, but is not limited to coal. Combustion gases from downstream of the furnace are recirculated back to the furnace, and are also introduced into the furnace from the four corners, in a tangential manner. The coal is introduced along with primary air to be directed at the smallest of a series of concentric imaginary circles; the recirculated gases are directed tangentially at a somewhat larger imaginary circle; and the secondary air is directed tangentially at a still larger imaginary circle.
Abstract: A coal feed system for use in a fluidized bed combustor in which a grate is supported in a housing and is adapted to support a bed of particulate material including a combustible fuel. Air is passed through the grate and into the bed to fluidize the particulate material. The particulate fuel material is separated externally of the bed into a relatively coarse material and a relatively fine material. The fine material is agglomerated and it, along with the coarse material, is passed to a distributor which distributes the material onto selected areas extending across the upper surface of the bed.
Abstract: A flash smelting burner is provided which consists of an assembly of feed pipes for solids and gas, which discharge into a mixing tunnel, the feed pipes being concentric at the point of discharge so that gas is fed into the mixing tunnel from an annular opening between the feed pipes, the solids feed pipe having a bend therein and being provided with apertures which enable a small proportion of the gas stream to enter the solids feed pipe at the bent region thereof.
Abstract: An improved fuel-air admission assembly incorporating a split coal bucket which permits a pulverized coal-fired furnace to be operated at low loads without the use of auxiliary fuel to provide stabilization. The split coal bucket comprises an upper and a lower coal nozzle pivotally mounted to the coal delivery pipe, the upper and lower coal nozzles being independently tiltable. When the furnace is operating at low loads, the primary air and pulverized coal stream discharging from the coal delivery pipe is split into a first and a second coal-air stream and independently directed into the furnace by tilting at least one of the nozzles away from the longitudinal axis of the coal delivery pipe, thereby establishing an ignition stabilizing pocket in the locally low pressure zone created between the spread apart coal-air streams.
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: Pulverized coal is ignited, to furnish energy for warm-up or low load operation of a coal burning furnace, by a technique which does not require the combustion of significant quantities of liquid or gaseous fuels. The direct ignition of pulverized coal in accordance with the present invention contemplates the delivery of a dense phase coal/air stream to an ignition zone where it receives ignition energy and the thus ignited mixture is thereafter contained in a recirculation region until the flame becomes self-sustaining.
Abstract: A method of direct ignition of pulverized coal to furnish energy for warm-up or low load operation of a coal burning furnace comprises forming a fuel stream consisting of a mixture of pulverized coal and air, the fuel stream having an air to coal ratio and/or a flow velocity which fluctuates. The fluctuating fluid stream is introduced into a combustion area where the coal is ignited by an energy source. The fluctuation of the air to coal ratio and/or the fluctuation of the flow speed provide for the air to coal ratio and/or the flow speed to be swept through a range of values which includes the optimum conditions for ignition.
Abstract: A tangentially fired pulverized coal furnace in which the means for introducing fuel and air from the corners operate as independent firing systems at low ratings and contribute to the fireball at higher ratings. The coal flow through a nozzle is deflected radially outwardly at low ratings and allowed to continue essentially straight at high ratings. A surrounding secondary air flow is concentrated at the coal stream and may be varied from a swirling action at low ratings to a parallel flow action at high ratings.
Abstract: Apparatus and methods are provided for reducing solid combustible particles by heat and abrasion to a condition in which they can be burned completely and without the production of objectionable solid particulates in the exhaust gases. Solid combustible particles are carried into an outer chamber of the device by a low pressure transport air stream, with additional air at high pressure and high velocity being introduced into the same chamber in a relation driving the solid particles rapidly and circularly within the outer chamber and about an inner chamber of the device. Impingement of the particles against one another and/or the walls of the outer chamber during such swirling motion, supplemented by partial oxidation of the combustibles, raises the temperature of the particles and comminutes or reduces their sizes to form a very highly combustible flowable aerosol mass which will burst into flame when contacted by a stream of secondary combustion air.