Method and apparatus for high temperature heating, melting, refining and superheating of materials, such as steel scrap, metals, ceramics or glass. The invention provides an economizing method of hydrocarbon fluid fuel combustion in an ongoing flame in a liquid cooled combustion chamber by separately supplying streams of fuel and at least two oxidizing gases wherein a first oxidizing gas reacts with the fuel, and a second oxidizing gas is directed about the flame core to further react with the fuel, while controlling the flow of the fuel, the oxidizing gases and cooling liquid to provide the required heat input, combustion product chemistry, temperature, velocity, emissivity and combustion block temperature. Also disclosed are burners for carrying out the invention.

Variable heat generating method and apparatus

A burner (10) and method is disclosed in which a first oxidizing gas (14) containing a high oxygen concentration is injected as a stream into the central zone of a combustion tunnel (12), and part of the fuel (18) is injected (19) into said central pyrolysis zone to mix with said first oxidizing gas to create a highly luminous, high temperature flame core containing microparticles of carbon of the proper size for maximum luminosity and high temperature, and a relatively small amount of hydrocarbon radicals. In addition, the remaining part of the fuel is injected (20) in a plurallity of streams about said flame core to mix with a second oxidizing gas (15) containing a lower oxygen concentration than the first oxidizing gas and injecting said second oxidizing mixture about said flame core and said remaining fuel flow to mix with said remaining fuel flow. This creates a plurality of fuel lean flames which are directed toward said luminous flame core to form a final flame pattern having high temperature, high luminosity and low NOx content.

Method and apparatus for generating highly luminous flame

A method comprising injecting a primary fuel and air into a furnace to burn the fuel and form a first-stage combustion zone, the fuel being diluted with surrounding combustion gas and the air being supplied at a rate in excess of the stoichiometric rate required for the combustion of the fuel, and injecting a secondary fuel into the furnace around or downstream of the first-stage zone at a range approximately equal to the stoichiometric rate required for the consumption of the excess oxygen resulting from the combustion in the first-stage zone the fuel being diluted with surrounding combustion gas and to form a second-stage combustion zone around or downstream of the first-stage zone.

Multi-stage combustion method for inhibiting formation of nitrogen oxides

A burner/injector for providing a localized impingement flame or multiple flames for scrap heating and melting through use of a fluid fuel and at least one oxygen rich oxidizing gas. The burner/injector includes a liquid-cooled combustor for generating an impinging flame directed toward a scrap pile and a structure for injecting a controllable amount of a solid carbonaceous fuel and a controllable flow of high velocity oxidizing gas into space that has been previously occupied by the impinging flame. The burner/injector may be equipped to inject a solid slag forming materials and/or slag deoxidizing materials, and/or to inject an additional oxidizing gas for burning a small portion of preheated scrap, post-combustion of CO and iron-carbon melt refining. The burner/injector may be arranged as a simple liquid-cooled combustor permanently mounted through the furnace wall or roof, and may be equipped with single or multiple channels for injection of solid material and high velocity oxidizing gas. Separate injecting lances for high velocity oxidizing gas and/or solid carbonaceous fuel may be mounted on the furnace. Both the lances and the combustors may be equipped with a nozzles for additional injection of the additional oxidizing gas.

Apparatus for electric steelmaking

A combustor includes an end cap having upstream and downstream surfaces and a cap shield surrounding the upstream and downstream surfaces. First and second sets of premixer tubes extend from the upstream surface through the downstream surface. A first fuel conduit supplies fuel to the first set of premixer tubes. A casing circumferentially surrounds the cap shield to define an annular passage, and a second fuel conduit supplies fuel through the annular passage to the second set of premixer tubes. A method for supplying fuel to a combustor includes flowing a working fluid through first and second sets of premixer tubes, flowing a first fuel into the first set of premixer tubes, and flowing a second fuel through an annular passage surrounding the end cap and into the second set of premixer tubes.

Combustor and method for supplying fuel to a combustor

In the operation of a burner using gaseous fuel the production of nitrogen oxides is limited and controlled by providing successive stages of combustion and by holding down the temperature of combustion. This is accomplished by introducing the fuel in two streams of unequal volume and comprising respectively more and less than the stoichiometric percentage of air, igniting the streams in sequence, thus effecting first and second stages of combustion, and mixing and consuming the excess fuel and air of said streams respectively, thus effecting a third stage of combustion.

G Schwedersky

Papers

Burner and method of operating it to control the production of nitrogen oxides