Abstract: Air heated outside the calcining zone of a shaft kiln is passed through raw material in a hopper mounted above the kiln in order to preheat the raw material. In one embodiment the preheating air is heated by an excess air burner which communicates with the hopper. In another embodiment, the hot calcined material is cooled by forcing cool air through it and the heated air is utilized as preheating air by directing it through a by-pass conduit which connects the cooling zone of the kiln with an extension of the hopper. In neither embodiment does the preheating air constitute combustion supporting air.

Abstract: In apparatus and method for treating granular product within a cylindrical chamber as the product, by the force of gravity, falls through a plurality of regions maintained at varying temperature and pressure. Structure formed by at least a pair of collectors is connected tangentially to a housing surrounding the regions to withdraw gas from and reintroduce gas to the cylindrical chamber. Particularly gas is withdrawn from a lower region, treated by heating and dilution with flue gases prior to reintroduction. Movement of gas is provided by a ventilator which serves to draw fresh air into the cylindrical chamber from the vicinity of the lower region. The flow of gas, the temperature of the gas, and the pressure within the regions result in granular product first moving counter to the flow of gas, then with the flow of gas, and then counter to the flow of gas. The granular product is heated, maintained at a heated temperature, and cooled within these flows.

Abstract: Either sulphur-containing raw materials or sulphur-containing fuels may be used in the calcination of mineral raw materials in a calcining furnace, with significant desulphurization of the calcined material being achieved if, on the one hand, cooling air introduced into the cooling zone of the furnace is removed at the upper end of the cooling zone thereof through exhaust ducts and if, on the other hand, the flue gases are free of oxygen and have a carbon monoxide content of 1 to 5% by volume. In order to obtain this composition of the flue gases, the combustion process can either be performed in the calcining zone of the calcining shaft of the furnace with a deficiency of air or a gaseous, liquid or solid fuel can be supplied by means of fuel tubes located at a transfer duct between the furnace shafts.

Abstract: A vertical shaft furnace for continuously melting metal materials, such as scrap, copper cathode pieces and the like is disclosed. The furnace comprises an elongated cylindrical melting chamber having an opening in the upper portion thereof for intermittently gravity-charging the furnace with metal pieces, which form a descending metal column in the melting chamber. A plurality of plasma arc generators is mounted in the sidewalls of the melting chamber extending inwardly thereof in a downwardly inclined attitude. The plasma arc torches are arranged in upper and lower vertically spaced planes for respectively preheating and melting the metal charged to the furnace. Protective refractory shrouds are provided which extend inwardly from the inside wall of the melting chamber and at least partly surround the plasma arc torches to substantially prevent damage to the torches by the descending or dropped metal charge.

Abstract: Coking of liquid fuel supplied through a fuel lance in a calcining furnace is prevented by surrounding a fuel tube in the fuel lance with a tubular jacket forming an annular gap between the jacket and the fuel tube for supplying a cooling medium through the lance. The jacket may be additionally provided with insulation which can be protected from damage caused by downwardly traveling bulk material by the additional provision of a protective tube.

Abstract: Finely-divided grain products in general and grain dust in particular are useful fuels which are advantageously employed in the drying of harvested grain to a moisture content suitable for storage and/or further processing. A grain dryer designed for such fuels provides for preheating and predrying fuel prior to feeding it to a burner.

Abstract: This invention relates to a kiln of a compact upright configuration which is constructed so as to successively preheat, heat, and then cool aggregate in a continuous operation while avoiding wasteful loss of heat from the walls of the kiln or in the effluent gases. In the apparatus of this invention there is provided an upright hollow housing having an air inlet opening in a lower portion thereof and an air outlet opening in an upper portion thereof. A fan is communicatively connected to the housing for causing outside air to enter the air inlet opening and flow upwardly through the housing. A fuel burner is provided in the housing for combusting a fuel and thereby heating the air flowing upwardly within the housing.

Abstract: This invention deals with a method of burning crushed or lump-sized combustible material, such as limestone, dolomite, magnesite or a similar material, in an annular shaft kiln having an annular outer shaft and an inner shaft, where the annular and the inner shafts are alternatively charged with fresh air and combustion gases, or are connected with the exhaust gas system. Furthermore, the invention deals with an annular shaft kiln for carrying out this method, which has a shaft insert that is open at the top, whereby the combustion material is selectively fed into the annular shaft formed around the shaft insert, or into the inner shaft which is formed inside the shaft insert. In a first operating position, the inner shaft adjacent its upper end is connected with the exhaust gas system, and combustion gas and combustion air are fed into the outer annular shaft.

Abstract: A furnace is disclosed for the heat treatment of mainly lumpy to fine grained material. The furnace is either a shaft furnace or a rotary furnace for the calcination or sintering of limestone, dolomite or magnesite. The calcination material passes through a preheating zone, a calcination zone and a cooling zone. The calcination zone has a gas feed and gas withdrawal device. A calcination device is provided in the calcination zone to which is connected a gas conveying device for the production of a hot gas circulation. The hot gas circulation device is situated between the gas withdrawal device and the calcination device and is provided as a conveying blower subjected to a cooling liquid.

Abstract: A coal slagging gasifier and method of operating such gasifier are improved by providing an improved slag removal orifice. The orifice is located centrally within the hearth of a gasifier of the type in which hot burner gases are directed up through the orifice to retain the slag in molten condition on the hearth and in which the slag is periodically discharged through the slag removal orifice. The slag removal orifice is formed as a substantially vertical passageway through the removable slag tap member which comprises a solid cast mass of high thermal conductivity metal having an integrally formed metal tube for circulating liquid coolant through the cast mass. The upper tundish surface of the slag tap member slopes downwardly and inwardly and merges with the slag removal orifice.

Abstract: In a device for raising the temperature of a plurality of solids which utilizes a heating chamber having at least one hot flue gas inlet and one or more solids inlet apertures to supply concurrent flows of solids and hot flue gas to a heating chamber, and, which utilizes at least one disengager to deflect the heated solids and prevent the solids from being exhausted from the heating chamber along with the hot flue gas, means are provided for coaxially mounting at least one hot flue gas outlet downstream of and displaced from at least one of the solids inlet apertures. Additionally, an individual disengager is associated with each hot flue gas outlet, each disengager being coaxially aligned with and positioned intermediate its associated hot flue gas outlet and a corresponding solids inlet aperture. Each individual disengager is positioned within a direct flow path of solids from a single solids inlet aperture, to prevent thermal stressing of the individual disengager.

Abstract: A removable annular hearth member, shaped to fit over the slag outlet member of a slagging gasifier, comprises a cast body of high thermal conductivity having integral liquid coolant passageways, the central openings of the annular hearth member and slag outlet member being arranged in vertical alignment for the discharge of slag, and the lower portion of the hearth member opening having a lip or beak extending downwardly so as to form a sealed joint with the slag outlet opening whereby in operation of the gasifier to prevent preparation of molten slag therebetween.

Abstract: The regenerating apparatus or furnace has gas burners mounted thereon to deliver combustion gas tangentially to a header and thence to distributing ports arranged circumferentially around and internally of a columnar bed of carbon being regenerated to provide uniform temperature distribution across the bed. In an alternate construction, the columnar bed is annular, headers are provided exteriorly and interiorly of the bed, and distribution ports conduct the combustion gas through the inner and outer walls defining the annular bed.

Abstract: A pilot flame to be positioned close to the charge opening of a cupola which uses carbon monoxide as a fuel in the presence of a fresh supply of combustion air, such carbon monoxide being drawn off from a position on the cupola where the temperature is above the self-ignition temperature of the carbon monoxide. Air preheated to a temperature above the self-ignition temperature of carbon monoxide may also be supplied.

Abstract: A removable annular hearth member, shaped to fit over the slag outlet of a slagging gasifier, comprises a cast body of high thermal conductivity having integral coolant passageways, said passageways being formed by shaping a metal tube into a coil having an inlet and an outlet, and casting metal to the desired shape around the coil such that the inlet and outlet communicate exteriorly of the cast body.

Abstract: A process and apparatus for burning limestone to produce calcined lime in which limestone is burned continuously in a vertical kiln provided with a plurality of fuel injectors which permit pulsed introduction of fuel so as to ensure a lamellar flow of fuel through the kiln and a controlled release of heat.

Abstract: A method of independently adjusting the fuel mixture composition and heating rate for a multiburner shaft furnace for the melting of metal, particularly copper and its alloys, fed in lump form to the shaft furnace, in which the burners are supplied with air and fuel gas and the heating rate is adjusted by controlling the pressure of one of the components of the fuel mixture (air or gas) in the manifold for supplying this component to a group of burners. The other fuel mixture component has its pressure controlled in its manifold by a single controller constituted by a pressure ratio controller.

Abstract: Reasons of ecology, health and prevention of corrosion require firing methods and furnaces with which the contents of soot and uncombustible gases such as carbon monoxide, hydrogen, hydrocarbons as well as nitrogen oxides and sulfur trioxides do not excess certain levels. This is obtained by a firing method in which a fuel is decomposed with deficient amounts of primary combustion air to combustible gases. Such gases are combusted by the admixture of secondary and tertiary combustion air amounts whereby a flame is obtained which is extended in space and time and, thus, the temperature of which does not rise above moderate values such as 1400.degree. C. Prior to being exhausted, the combustion gases are thoroughly mixed so as to obtain perfect combustion of possibly subsisting combustible substances. Exhausting takes place with heat withdrawal so that cool and pure combustion gases enter the ambiency.

Abstract: Reasons of ecology, health and prevention of corrosion require firing methods and furnaces with which the contents of soot and uncombustible gases such as carbon monoxide, hydrogen, hydrocarbons as well as nitrogen oxides and sulfur trioxides do not excess certain levels. This is obtained by a firing method in which a fuel is decomposed with deficient amounts of primary combustion air to combustible gases. Such gases are combusted by the admixture of secondary and tertiary combustion air amounts whereby a flame is obtained which is extended in space and time and, thus, the temperature of which does not rise above moderate values such as 1400.degree. centigrade. Prior to being exhausted, the combustion gases are thoroughly mixed so as to obtain perfect combustion of possibly subsisting combustible substances. Exhausting takes place with heat withdrawal so that cool and pure combustion gases enter the ambiency.

Abstract: A process and apparatus for burning limestone to produce calcined lime in which limestone is burned continuously in a vertical kiln provided with a plurality of fuel injectors which permit pulsed introduction of fuel so as to ensure a lamellar flow of fuel through the kiln and a controlled release of heat.

Abstract: The device and method of the invention embodies a shaft furnace containing no constrictions in the cross section of the shaft furnace that would unfavorably affect the movement characteristics in the filling. The arrangement of the pipes of the burning system in rings composed of closed arcuate pipe segments, adapted to the shape of the shaft furnace cross section and the provision of such pipes with a multiplicity of discharge openings for the fuel and the air of combustion which are uniformly distributed in intimate proximity to each other of horizontal rows of air and fuel pipes over the furnace periphery.According to the invention it is also feasible to arrange, in dependency on the furnace height and the material to be heat-treated, several pairs of ring pipe lines for fuel and air of combustion, either directly on top of each other in close proximity or in different combustion planes.

Abstract: In vertical continuous furnace calcining of lime, dolomite, magnesite, or the like, part of the air which is introduced at the lower end of the furnace chamber is drawn off in the area of the cooling zone within the chamber and is then reintroduced in encompassing relation into the material column in the firing zone within the furnace chamber and which is located immediately above the cooling zone, the remainder of the air flowing up through the column of material being treated in the chamber. Cleaning of the withdrawn cooling air and addition of fresh air are provided for.