Burner for a gas combustor and a method of operating the burner thereof

Abstract

A burner for a gas combustor and a method of operating the burner are disclosed. The burner includes a front surface area divided into a plurality of subareas and inlets arranged on the front surface area such that each subarea is encircled by at least four inlets and such that during operation of the burner, a gas recirculation in the combustor is facilitated corresponding to each subarea.

Description

FIELD OF INVENTION[0001]The present invention relates to a gas combustor burner particularly arrangement of inlets in the burner which supplies combustible gas to the combustor and its operation for fuel staging.BACKGROUND OF INVENTION[0002]Gas turbines are used to convert heat energy to mechanical energy, for example in power plants. Gas turbines have combustion chambers in which a fuel is burned with air. The combustion chambers of gas turbine plants are supplied with liquid and / or gaseous fuel using burner consisting of one or more nozzle or inlets. The burner can also be used to carry air required for the combustion. For the optimal operation of the gas compressors, stable flames should be formed in the combustion chamber during combustion. Common techniques for flame stabilization include the formation of small eddies or recirculation zones in the combustion chamber. The temperature in the recirculation zone needs to be above a threshold especially at lower load conditions to s...

AI Technical Summary

Benefits of technology

[0006]The underlying idea here is to provide gas recirculation inside a combustor by providing and operating inlets in at least one subarea which is smaller than that of front surface area of the burner. By operating the inlets encircling the subarea a gas recirculation or gas recirculations, if more than one subarea are operated, is formed which can maintain the sustainable temperature for the combustion. The number of subareas operated is based on the load of the gas turbine which can also be directly mapped to the combustor load. Operating the inlets in a subarea or subareas also enables staging the supply of combustible gas to the combustor for combustion. The combustion resulting in the creating of gas recirculation which is hot thereby resulting in maintaining the required temperature throughout the entire load range. By operating a single smaller subarea at lower loads, the combustion associated with that subarea can be sustained. This combustion creates hot recirculation which also provides stability to flames in the combustor provided for the combustion. As the load increases other subareas can be made operational to supply the combustible gas to the combustor. Practically, at least four inlets are required to realize a gas recirculation in a subarea. The staging of the combustible gas referred in the invention should also be interpreted as the staging of the fuel since the inlets are generally supplied continuous by air in industrial operations.

[0015]In another alternative embodiment, said burner operates on pre-mixed jet flames. Combustion systems based on pre-mixed jet flames offer special advantages over for example, swirl stabilized systems from the thermo-acoustic point of view, owing to the distributed heat release zones and the absence of swirl induced vortices. By appropriately selecting the jet impulse, small scale eddy structures can be created which dissipate the acoustically induced fluctuations of heat release, thereby suppressing the pressure pulsations which are typical for swirl stabilized flames.

Problems solved by technology

A flame will be inherently unstable if the energy release from the combustion is insufficient to raise the temperature to a level at which combustion is self sustaining under conditions of heat loss including radiation to and from the flame and under hot gas recirculation.

The ability to keep a sustainable temperature to maintain combustion at different loads especially at lower loads and simultaneously achieve emission targets is a great challenge in gas turbine operations.

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