Patent ID: 8899970

Claim:
A burner device ( 2 ) for an industrial furnace ( 1 ) comprising: a channel ( 3 ) for fuel, a channel ( 4 ) for a first oxidant, the channel ( 4 ) for the first oxidant being i) separate from the channel ( 3 ) for the fuel, and ii) outside of the channel ( 3 ) for the fuel, an outlet ( 9 ) for flue gases, a control device ( 10 ), and a heat buffer ( 7 ), wherein, said control device ( 10 ) is arranged to cause the first oxidant and the flue gases alternatingly to be led through the heat buffer ( 7 ), a separate lancing device ( 6 ) located in the channel ( 4 ) for the first oxidant, the lancing device ( 6 ), under control of said control device ( 10 ), supplying a second oxidant to the burner device ( 2 ) at a location inside the channel ( 4 ) for the first oxidant, the second oxidant being comprised of at least 80 percentage by weight oxygen, the lancing device ( 6 ) providing for the amount of second oxidant supplied to the burner device ( 2 ) to be varied during operation of the burner device and providing an ejector effect in the channel ( 4 ) for the first oxidant, wherein the lancing of the second oxidant is supplied in the channel ( 4 ) for the first oxidant but not in the channel ( 3 ) for the fuel, and the control device ( 10 ) controls an amount of the lanced secondary oxidant over time, so that different amounts of the lanced secondary oxidant are respectively provided during corresponding different heating stages of the furnace, the lancing device ( 6 ) is arranged, under control of said control device ( 10 ), to supply the second oxidant at a velocity which is at least sonic velocity such that the control device ( 10 ) controls the lancing of the second oxidant to provide high-velocity lancing at least at sonic velocity and the ejector effect, the lancing device ( 6 ) is arranged, under control of said control device ( 10 ), to supply the second oxidant through the same channel ( 4 ) as the first oxidant, the second oxidant is supplied, under control of said control device ( 10 ), downstream of the heat buffer ( 7 ) in relation to a gas flow direction towards the burner device ( 2 ), such that the lancing of the second oxidant is performed downstream of the heat buffer, and the burner device, under control of said control device ( 10 ), provides batchwise heating.