Abstract: A steam generator has a heat exchange chamber with an upstream end and a downstream end. The steam generator further has a burner that injects primary reactants, including fuel and combustion air, into the chamber at the upstream end. A first branch of a once-through water line is located within the chamber downstream of the burner. A second branch of the once-through water line is connected in parallel with the first branch, and is located within the chamber downstream of the first branch. A fuel injector is arranged to inject staged fuel into the chamber at a staged location downstream of the first branch of the once-through water line.

Abstract: A method includes the steps of operating a regenerative burner in cycles, including a firing cycle in which fuel and combustion air are discharged from the burner into a process chamber, and a nonfiring cycle in which a quantity of gas is withdrawn from the process chamber through a regenerative bed associated with the burner. The method further includes steps of detecting and responding to a temperature that differs from a predetermined temperature at a location in the process chamber. In a first step of responding to the detected temperature, a flue damper system is operated to vary a flow of gas within the process chamber relative to the location of the detected temperature. A second step of responding to the detected temperature reduces the quantity of gas to be withdrawn from the process chamber through the regenerative bed in a subsequent nonfiring cycle.

Abstract: A stack of copper plates is placed in a melting chamber having a closed roof of refractory material. The stack is placed in a tilted orientation leaning against a side wall of the melting chamber, with lower edges of the copper plates resting on an inclined hearth surface. A door to the melting chamber is closed to block the infiltration of oxygen. A burner is fired into the melting chamber to heat the closed roof of refractory material, and the stack of copper plates is melted under the influence of combustion products from the burner and heat radiated from the closed roof. Molten copper is drained downward from the bottom edge of the inclined hearth surface to avoid immersing the copper plates in a molten bath.

Abstract: A NOx suppression apparatus is configured for use with a burner that injects fuel into a stream of process air flowing into and through a rotary kiln. The apparatus comprises a premix injection system that forms a premix of fuel gas and air, and injects the premix into the stream of process air upstream of the burner port. This enables premix products of combustion to suppress the production of NOx by vitiating a combustion air portion of the process air before the combustion air portion combusts with fuel injected from the burner port.

Abstract: An indurating furnace has a heating station and an air passage leading to the heating station. A draft of preheated recirculation air is driven through the passage toward the heating station, and is mixed with fuel gas to form a combustible mixture of preheated recirculation air and fuel gas that ignites in the passage. This is accomplished by injecting the fuel gas into the passage in a stream that does not form a combustible mixture with the preheated recirculation air before entering the passage.

Abstract: A method includes the steps of operating a regenerative burner in cycles, including a firing cycle in which fuel and combustion air are discharged from the burner into a process chamber, and a nonfiring cycle in which a quantity of gas is withdrawn from the process chamber through a regenerative bed associated with the burner. The method further includes steps of detecting and responding to a temperature that differs from a predetermined temperature at a location in the process chamber. In a first step of responding to the detected temperature, a flue damper system is operated to vary a flow of gas within the process chamber relative to the location of the detected temperature. A second step of responding to the detected temperature reduces the quantity of gas to be withdrawn from the process chamber through the regenerative bed in a subsequent nonfiring cycle.

Abstract: An indurating furnace has a heating station and an air passage leading to the heating station. A draft of preheated recirculation air is driven through the passage toward the heating station, and is mixed with fuel gas to form a combustible mixture of preheated recirculation air and fuel gas that ignites in the passage. This is accomplished by injecting the fuel gas into the passage in a stream that does not form a combustible mixture with the preheated recirculation air before entering the passage.

Abstract: An apparatus includes a furnace structure defining a combustion zone, and a tube that discharges fuel-oxidant premix into the combustion zone through an outlet from the tube. A reactant supply system provides the tube with unmixed fuel and oxidant for forming the premix. A flashback control means inhibits or extinguishes flashback in the tube.

Abstract: A stack of copper plates is placed in a melting chamber having a closed roof of refractory material. The stack is placed in a tilted orientation leaning against a side wall of the melting chamber, with lower edges of the copper plates resting on an inclined hearth surface. A door to the melting chamber is closed to block the infiltration of oxygen. A burner is fired into the melting chamber to heat the closed roof of refractory material, and the stack of copper plates is melted under the influence of combustion products from the burner and heat radiated from the closed roof. Molten copper is drained downward from the bottom edge of the inclined hearth surface to avoid immersing the copper plates in a molten bath.

Abstract: Hot products of combustion are provided beside an outer surface of a load to be heated, and are given a non-uniform temperature profile in a control direction extending across the outer surface of the load. The non-uniform temperature profile of the hot products of combustion is varied within a range that is predetermined relative to the distance that the outer surface of the load extends in the control direction, whereby the load can be given a predetermined temperature profile in the control direction.

Abstract: A method of firing a burner into a furnace process chamber supplies the burner with fuel and combustion air at a ratio that provides a level of excess air. The method includes the steps of reducing the flow rate of combustion air, and maintaining the level of excess air when the flow rate of combustion air is being reduced. Other steps include withdrawing exhaust gas from the process chamber, and supplying the burner with the exhaust gas at an increasing flow rate when the flow rate of combustion air is being reduced.

Abstract: A submerged combustion vaporizer may include a premix burner with multiple integral mixers for forming premix and discharging the premix into the duct system that communicates the burner with the sparger tubes. The SCV may further include a NOx suppression system that injects a staged fuel stream into the exhaust in the duct system, and/or a NOx suppression system that mixes water with the premix.

Abstract: A burner has a port facing into a combustion chamber along an axis. A secondary fuel injector structure has secondary fuel injection ports that face into the combustion chamber at locations spaced radially outward from the burner port. A tertiary fuel injector structure has tertiary fuel injection ports that face into the combustion chamber in directions perpendicular to the axis at locations spaced axially downstream from the secondary fuel injection ports.

Abstract: A burner fires into a radiant tube to provide a downstream flow of combustion products within the radiant tube. Staged fuel is injected upstream into the radiant tube. A recirculation conduit inside the radiant tube receives the staged fuel along with combustion products that are inspirated into the recirculation conduit by the staged fuel. The recirculation conduit has an outlet for discharging a mixture of the inspirated combustion products and staged fuel into the downstream flow of combustion products.

Abstract: A burner has a port facing into a combustion chamber along an axis. A secondary fuel injector structure has secondary fuel injection ports that face into the combustion chamber at locations spaced radially outward from the burner port. A tertiary fuel injector structure has tertiary fuel injection ports that face into the combustion chamber in directions perpendicular to the axis at locations spaced axially downstream from the secondary fuel injection ports.

Abstract: A burner has a port facing into a combustion chamber along an axis. A secondary fuel injector structure has secondary fuel injection ports that face into the combustion chamber at locations spaced radially outward from the burner port. A tertiary fuel injector structure has tertiary fuel injection ports that face into the combustion chamber in directions perpendicular to the axis at locations spaced axially downstream from the secondary fuel injection ports.

Abstract: A submerged combustion vaporizer may include a premix burner with multiple integral mixers for forming premix and discharging the premix into the duct system that communicates the burner with the sparger tubes. The SCV may further include a NOx suppression system that injects a staged fuel stream into the exhaust in the duct system, and/or a NOx suppression system that mixes water with the premix.

Abstract: An apparatus for melting a metal load includes a furnace having a melting chamber with a hearth and a molten metal outlet. The apparatus further includes non-regenerative burners that are operative to fire into the melting chamber, and regenerative burners that also are operative to fire into the melting chamber. The method includes the steps of firing non-regenerative burners into the chamber to provide heat for melting the load, and also firing regenerative burners into the chamber to provide heat for melting the load.

Abstract: Hot products of combustion are provided beside an outer surface of a load to be heated, and are given a non-uniform temperature profile in a control direction extending across the outer surface of the load. The non-uniform temperature profile of the hot products of combustion is varied within a range that is predetermined relative to the distance that the outer surface of the load extends in the control direction, whereby the load can be given a predetermined temperature profile in the control direction.

Abstract: An apparatus for melting a metal load includes a furnace having a melting chamber with a hearth and a molten metal outlet. The apparatus further includes non-regenerative burners that are operative to fire into the melting chamber, and regenerative burners that also are operative to fire into the melting chamber. The method includes the steps of firing non-regenerative burners into the chamber to provide heat for melting the load, and also firing regenerative burners into the chamber to provide heat for melting the load.