Abstract: The stack gas from a shaft furnace in which iron ore is directly reduced is cooled and filtered and then subjected to steam so as to convert its carbon monoxide into carbon dioxide and water. The carbon dioxide and water are then scrubbed out of this stack gas so as to leave virtually pure hydrogen which is heated to a temperature between 400.degree. and 600.degree. C and added to the output of an oxygen reactor that transforms coal and oxygen into a synthetic gas having a carbon-monoxide/hydrogen volume ratio of at least 1.5:1. The addition of this hydrogen to the output of the reactor lowers the volume ratio to 1:1 at most so that this mixture can be reintroduced into the shaft furnace at a temperature of around 1000.degree. C as a reducing gas.

Abstract: In a shaft furnace for the direct reduction of iron ore in which hot reducing gas is introduced at the bottom of the furnace and removed from the top of the furnace, means for recirculating at least a portion of the furnace exhaust gas are provided along with means for introducing fresh gas into the recirculated gas stream and means to heat the gas stream introduced into the furnace. The improvement comprises providing means for desulfurizing the fresh gas stream prior to its joining the recycled exhaust gas and providing for dust removal, sulfur and CO removal in the recycled gas stream prior to its joining the fresh gas stream.

Abstract: Device for removing carbonizable residues includes a closed furnace heatable to low-level carbonization temperature, the furnace having an outlet for carbonization gases formed therein, means for burning off carbonization gases from carbonizable residues and utilizing the heat of combustion therefrom for heating the furnace, the means comprising a burner and a combustion chamber connected to the burner and forming part of a hot gas circulatory system, the hot gas circulatory system also including a container wherein the furnace is disposed so as to be heatable by hot gas circulating through the hot gas circulatory system, a carbonization gas return line connecting the furnace and the combustion chamber for returning to the combustion chamber carbonization gases formed in the furnace, and an inert gas line communicating with the interior of the furnace for supplying inert gas thereto.

Abstract: A reverberatory furnace which has an external passage for recycling hot exhaust gases from the furnace chamber back to the main burner port, means for introducing additional air or oxygen into the recycling passage, and a main burner which supplies fuel plus up to 50 percent of the air or oxygen required for total combustion into the furnace chamber so that the air or oxygen added to the recycling passage is thereby preheated by the exhaust gases and mixes with the fuel-rich mixture from the burner to provide complete combustion of the exhaust gases while simultaneously reducing the cost of the fuel requirement because of the preheating effect of the exhaust gases on the additional supply of air or oxygen.

Abstract: A method of extending the useful life of a catalyst employed in the endothermic catalytic reforming of gaseous hydrocarbons in which a substantial portion of the sulfur contained in such gaseous hydrocarbons is removed by contacting them with an aqueous solution of a water soluble metallic salt having a free metallic ion which forms an insoluble precipitate with sulfur. A preferred salt is zinc chromate.

Abstract: A method of producing metallic iron pellets in a generally vertical furnace in which a gravitational flow of particulate material is reduced in a reducing zone by a countercurrent flow of a reducing gas containing a reductant, the spent reducing gas is removed and cooled and a portion is introduced as a cooling gas in a cooling zone near the bottom of the furnace while a second portion is employed as a fuel to heat a catalyst through which a gaseous hydrocarbon and steam are passed to form a reducing gas mixture for introduction into the furnace, and a portion of the cooling gas is upgraded in reducing potential and introduced to the reducing zone as reducing gas. Apparatus is also provided for carrying out the method.

Abstract: A method and apparatus for the recovery of gases issuing from a metallurgical refining furnace or converter, in which said gases are drawn off through a hood disposed above the outlet of the furnace and are entered as a gas column into a combustion chamber from which the burnt gases are drawn off by a main blower while air is simultaneously drawn from a space around the furnace adjacent to the inlet of said hood by means of an auxiliary blower and is forced into said combustion chamber to burn combustible components of said gases therewithin, the invention further including withdrawing a fraction of said combustible gases by sucking them from said gas column within the combustion chamber substantially before they are mixed with burnt combustion products generated within said combustion chamber to send said withdrawn fraction to utilization means which are external to said combustion chamber, and the invention further including the control of the rates of flow of the gases through various conduits in the syste

Abstract: Apparatus for direct reduction of iron ore containing sulfur comprises a shaft type reduction furnace with means for withdrawing two separate streams of spent reducing gas. One stream, being substantially free of sulfur is recycled through a catalytic reformer to produce fresh reducing gas. The other stream containing sulfur, is connected to process equipment such as a burner where sulfur is not of consequence.

Abstract: A process and apparatus for the gaseous reduction of sized iron ores wherein a steam-hydrocarbon fluid mixture, having a steam:carbon molar ratio ranging from 0.9:1 to 1.8:1, is catalytically reformed to produce a reducing gas mixture containing about 85% to 98% by volume carbon monoxide plus hydrogen, with a hydrogen:carbon monoxide volume ratio of at least 2:1. The reducing gas is transferred directly at elevated temperatures to a shaft furnace for reduction of ores therein, and the spent reducing gas is cleaned, cooled and dried, for use as fuel and/or cooling the reduced ores.

Abstract: A high efficiency aluminum scrap melting system is provided in which a portion of the hot combustion gases employed to melt the aluminum in a hearth is recycled through scrap-receiving preheat compartments to preheat scrap and volatilize contaminants as the scrap is fed to the hearth, the remainder of the hot combustion gases leaving the hearth as hot exhaust gases being optionally employed through a recuperator to preheat air which is fed to a combustion burner system used to burn hydrocarbon fuel and provide heat for the overall system. Energy available in the contaminants also supplements the energy supply to the system.

Abstract: The invention covers methods and apparatus for controlled flue gas combustion during operation of a closed electric arc reduction furnace to produce metals and metal alloys while feeding a burden to the furnace chamber. The furnace chamber is closed by means of a flue gas hood of reduced height, complete with electrode conduits, gas exhaust pipes and charge devices. The flue gas hood is provided with one or more controlled recycled combustion gas and air supplies, through which combustion air and recycled gas enters the furnace chamber at spaced points thereover for maintaining a reduced temperature level adjacent the hood ceiling surface. The quantities introduced depend upon the prevailing temperature and/or gas analysis of the flue gas in the furnace chamber.

Abstract: Apparatus for producing protective reducer gas, for use in plant having main and auxiliary burners for burning liquid or gaseous fuels, and designed either for heating purposes or for ore reduction processes. The apparatus includes a common cooling chamber into which the hot waste gases from the main and/or auxiliary burners can be fed selectively, the auxiliary burner being located immediately above the chamber with a combustion pipe extending downwards into the cooling chamber. Cooling water is injected directly into the upper part of the cooling chamber and withdrawn from the lower end. The waste gases from the main burner are admitted through a pipe terminating between the levels of two outlets in a side wall of the cooling chamber, the lower one having a valve closure, to control the level of the cooling water and so form a water seal for the waste gas inlet. The protective gas outlet is in the upper part of the cooling chamber.

Abstract: In a method for melting a material in a vertical shaft furnace having an upper portion, a lower combustion zone portion and an intermediate post-burning portion, said upper and lower portions being separated by a restriction and wherein coke is burned and the material melted in said lower combustion zone by introducing a blast of air close to the bottom of the lower combustion zone to produce combustion gases containing CO and/or H.sub.