Premixing burner and method for operating a premixing burner

Abstract

A method for operating a premixing burner is provided. The premixing burner includes a premixing zone. An air mass flow and fuel may be injected into the premixing zone, and a potential hot gas backflow area may form. A fluid containing no fuel is injected downstream from the fuel injection into the premixing zone in order that a hot gas backflow area does not form. A premixing burner including a premixing zone is also provided.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This application is the US National Stage of International Application No. PCT / EP2008 / 059658, filed Jul. 23, 2008 and claims the benefit thereof. The International Application claims the benefits of European Patent Office application No. 07014820.0 EP filed Jul. 27, 2007. All of the applications are incorporated by reference herein in their entirety.FIELD OF INVENTION[0002]The present invention relates to a premixing burner, especially a syngas premixing burner, and to a method for operating a premixing burner.BACKGROUND OF INVENTION[0003]Premixing burners typically comprise a premixing zone in which air and fuel are mixed before the mixture is directed into a combustion chamber. The mixture burns in said chamber, with a hot gas under increased pressure being generated. The hot gas is transferred on to the turbine. The primary consideration when operating premixing burners is to keep nitrous oxide emissions low and to avoid a flame blowba...

AI Technical Summary

Benefits of technology

[0014]In respect of nitrous oxide minimization the addition of inert mass flows as a thinning medium into the air mass flow or the fuel mass flow (quenching) is usual. The use of the leaner premix technology makes it possible to reduce the quantity of the quenching medium employed, which enhances the economy of the plant. However the lack of inerting then means that the fuel is highly reactive.

[0015]The object of the present invention is to provide an advantageous method for operating a premixing burner in which the formation of hot gas flowback regions is avoided. A further object of the present invention is to provide an advantageous premixing burner.

[0018]By the local injection of for example cold air into the trail or flowback regions, the formation of said regions within the premixing zone of the burner is largely prevented. And least the fuel in these regions is quenched and cooled off to the extent that no reaction or no ignition of the fuel-air mixture within the premixing zone of the burner can occur. This makes a secure premixing operation of the burner possible.

[0024]The local injection of a fluid into the potential hot gas flowback region largely avoids the formation of the hot gas flowback region within the premixing zone of the burner. At the least however the hot gas in the hot gas flowback region is quenched and cooled off such that no reaction in the form of an ignition of the air-gas mixture within the premixing zone of the burner can occur. This prevents flame blowbacks and reduces the nitrous oxide formation, but also allows a secure premixing operation of the burner.

[0026]The injection nozzles can be located on the cone side and / or on the hub side of the premixing zone. Advantageously the fuel nozzles are arranged in one or more rows lying behind one another downstream of the air swirl generator. This makes a graduated fuel injection possible. Furthermore the fuel nozzles and / or the openings can be located in the air swirl generator, preferably in at least one swirler vane.

Problems solved by technology

However the lack of inerting then means that the fuel is highly reactive.

Images