Embodiments of the present invention include high-temperature staged recirculating burners and radiant tube burner assemblies that provide high efficiency, low NOx and CO emissions, and uniform temperature characteristics. One such staged recirculating burner includes a combustion tube having inside and outside helical fins forming opposing spiral pathways for combustion gases and products of combustion, a combustion nozzle coupled to the combustion tube, a gas tube running axially into the combustion tube, and a staging gas nozzle coupled to the gas tube, where the staging gas nozzle includes radial exit holes into the combustion tube and an axial gas staging tube extending into the combustion nozzle to stage combustion.

A combustion method in which heated flue gas heats a regenerator through which a mixture of fuel and flue gas is then passed to undergo endothermic reactions that produce syngas which is fed into a furnace together with a motive gas stream.

A combustion method in which heated flue gas heats a regenerator through which a mixture of fuel and flue gas is then passed to undergo endothermic reactions that produce syngas which is fed into a furnace together with a motive gas stream.

The invention is directed to a method for reducing NOx emission from an industrial process furnace comprising a firebox containing a burner and a tube, which method comprises subjecting an oxidant gas and/or a fuel gas (1) to humidification, thereby obtaining a humidified gas; and pre-heating the humidified gas with an external waste heat stream (20) before feeding the gas to the burner.

The invention is directed to a method for reducing NOx emission from an industrial process furnace comprising a firebox containing a burner and a tube, which method comprises subjecting an oxidant gas and/or a fuel gas (1) to humidification, thereby obtaining a humidified gas; and pre-heating the humidified gas with an external waste heat stream (20) before feeding the gas to the burner.

The disclosure relates to a melting furnace, for example a two-chamber furnace, for the recovery of aluminum from aluminum scrap. This has a scrap chamber (2), with a dry hearth (6), the surface of which provided for receiving aluminum scrap is arranged above the surface of an aluminum melt (7) located in the scrap chamber (2) during operation of the melting furnace (1), and a heating chamber (3), which has at least one burner (9) for fuel firing, the heating chamber (3) and the scrap chamber (2) being separated from one another by a partition wall (11), the partition wall (11) having at least one opening (12) for recirculation of the aluminum melt (7) between the heating chamber (3) and the scrap chamber (2). Further, a refractory lining of the surface of the dry hearth (6) and/or a refractory lining of the inner wall of the scrap chamber (2) in the region of the dry hearth (6) have channels (18) which can be acted upon by hot gas and are designed to absorb heat from the hot gas and to release it to the aluminum scrap located on the surface of the dry hearth (6) for its thermal pretreatment.

The disclosure relates to a melting furnace, for example a two-chamber furnace, for the recovery of aluminum from aluminum scrap. This has a scrap chamber (2), with a dry hearth (6), the surface of which provided for receiving aluminum scrap is arranged above the surface of an aluminum melt (7) located in the scrap chamber (2) during operation of the melting furnace (1), and a heating chamber (3), which has at least one burner (9) for fuel firing, the heating chamber (3) and the scrap chamber (2) being separated from one another by a partition wall (11), the partition wall (11) having at least one opening (12) for recirculation of the aluminum melt (7) between the heating chamber (3) and the scrap chamber (2). Further, a refractory lining of the surface of the dry hearth (6) and/or a refractory lining of the inner wall of the scrap chamber (2) in the region of the dry hearth (6) have channels (18) which can be acted upon by hot gas and are designed to absorb heat from the hot gas and to release it to the aluminum scrap located on the surface of the dry hearth (6) for its thermal pretreatment.

A radiative recuperator preheats oxidant and/or fuel for combustion at one or more burners of a furnace. The recuperator includes a duct, at least portions of which comprise a material having a thermal conductivity of greater than 1 W/(m.Math.K), preferably greater than 3 W/(m.Math.K), that receives hot flue gas produced by the burner(s). The duct radiatively transfers heat to oxidant or fuel (for preheating) flowing through one or more metallic pipes disposed in between the duct and an insulating wall.

A radiative recuperator preheats oxidant and/or fuel for combustion at one or more burners of a furnace. The recuperator includes a duct, at least portions of which comprise a material having a thermal conductivity of greater than 1 W/(m.Math.K), preferably greater than 3 W/(m.Math.K), that receives hot flue gas produced by the burner(s). The duct radiatively transfers heat to oxidant or fuel (for preheating) flowing through one or more metallic pipes disposed in between the duct and an insulating wall.

Furnace operation includes consecutive cycles of a heating step, a stopping step and a restarting step. The fuel and/or the oxidizing agent is preheated upstream of the furnace by indirect exchange with the discharged fumes through a medium passing through a chamber. A first wall separates the fumes from the medium in the chamber. The fuel and/or oxidizing agent is separated from the medium in the chamber by second wall. During restarting, the medium's flow rate Dm is regulated to limit the heating rate of the first wall until it reaches the operational temperature at an end thereof.