Abstract: A gas-fired burner incorporating an air driven jet pump for mixing air, fuel, and recirculated flue gas is disclosed. The burner is configured for the staged introduction of combustion air to provide a fuel-rich combustion zone and a fuel-lean combustion zone. The burner achieves reduced NO.sub.x emission levels in high temperature applications which use preheated combustion air.

Abstract: Gas-solids transport and heat exchange techniques are disclosed wherein solid particulate material is circulated in a "figure 8" or a circular flow path for selective contact and/or direct heat exchange with gaseous media. The particulate material is introduced into streams of gaseous media at spaced locations in the flow path and subsequently separated from the gaseous streams following contact and/or heat exchange therewith. The gaseous streams are maintained separate from one another by loose packed bed columns of particulate material formed in the flow path and used to introduce the particulate material into the gaseous streams. The flow rate of the particulate material is regulated by the controlled biasing of particulate material from each of the columns thereof directly into the gaseous streams, and the particulate material is circulated solely through the use of the gaseous media and the force of gravity.

Abstract: A process for melting a ferrous burden comprising scrap iron, scrap steel, pig iron, direct reduced iron or mixtures thereof without the use of coke is provided. Air or enriched air as a primary oxidant is preheated and together with fuel is combusted to form a reducing atmosphere in a shaft furnace or forehearth which melts the ferrous burden in the melting zone of the shaft furnace. The reducing atmosphere leaving the melting zone of the shaft furnace is further combusted with a secondary oxidant in the preheating zone of the shaft furnace. The top gas from the preheating zone of the shaft furnace is combusted with a tertiary oxidant to provide a heated flue gas to preheat the primary oxidant. Optionally, the heat remaining in the flue gas after preheating the primary oxidant may be recovered in a waste heat recovery device.

Abstract: A recuperative burner having a recirculating conduit to direct flue gas to the combustion chamber with the air and fuel, and a compact recuperative stack with a recuperative flue gas conduit and an air passage in which air separated from the flue gas by the recuperative flue gas conduit is preheated before supplying it to the combustion chamber.

Abstract: Gas-solids transport and heat exchange techniques are disclosed wherein solid particulate material is circulated in a "figure 8" or a circular flow path for selective contact and/or direct heat exchange with gaseous media. The particulate material is introduced into streams of gaseous media at spaced locations in the flow path and subsequently separated from the gaseous streams following contact and/or heat exchange therewith. The gaseous streams are maintained separate from one another by loose packed bed columns of particulate material formed in the flow path and used to introduce the particulate material into the gaseous streams. The flow rate of the particulate material is regulated by the controlled biasing of particulate material from each of the columns thereof directly into the gaseous streams, and the particulate material is circulated solely through the use of the gaseous media and the force of gravity.

Abstract: A improved burner for metallurgical furnaces capable of utilizing gaseous or liquid fuels and air, enriched air or oxygen as an oxidant and adapted to accommodate rich fuel/oxidant mixtures is disclosed. The burner is capable of producing high temperatures and a reducing and non-decarburizing atmosphere without causing carbonization or other fouling of the burner or related furnace and without damaging the burner.

Abstract: A process and apparatus for the production of intermediate hot metal suitable for further refining into steel is disclosed.The basic process includes the steps of heating a charge of ore in a reducing furnace having a reducing atmosphere therein comprising a mixture of reconditioned and recycled top gas from the reducing furnace and off-gas rich in hydrogen and carbon monoxide produced by a cupola melting unit to reduce the ore to iron, partially carburizing the reduced iron in the reducing furnace with carbon-containing off-gas produced by the cupola melting unit, and melting the reduced and carburized iron together with scrap, slag forming additives and fluxes in a cupola melting unit having a reducing atmosphere therein produced by the combustion of a rich fuel/oxidant mixture to form a molten slag and molten iron suitable for the further refining to produce steel.

Abstract: A burner for burning a vaporizable liquid fuel, comprising a suction chamber, a combustion chamber, an air inlet to the suction chamber, a vaporizing chamber, a first passage interconnecting the combustion chamber with the vaporizing chamber, a second passage interconnecting the vaporizing chamber with the suction chamber, a liquid fuel inlet atomizer connected to the vaporizing chamber, and a vortex generator at the interface of the fuel inlet atomizer, first passage, and vaporizing chamber, the generator swirling hot combustion gases from the first passage into a vortex, into which vortex the fuel inlet atomizer directs atomized liquid fuel, the first passage, vortex generator, vaporizing chamber, and second passage together defining a recirculation path, the path having sufficient width to maintain blue-flame combustion, whereby the fuel will be vaporized by hot combustion gases as it passes through the vortex generator and the vaporizing chamber, the air inlet creating a suction which draws hot combustion