Low Calorific Fule Combustor For Gas Turbine

A can combustor for burning fuels with low calorific values, the combustor comprising:

• a generally cylindrical housing having an interior, a longitudinal axis, an annular inlet for receiving compressed air at one open longitudinal housing end with the other longitudinal housing end being closed;
• a generally cylindrical combustor liner coaxially disposed in the housing interior, the liner and the housing defining a generally annular flow passage for the compressed air received through the housing inlet, an interior of the liner defining a combustion zone adjacent the closed housing end and a dilution zone distant the closed housing end, the combustion zone including a recirculation region for primary combustion and an intermediate region for secondary combustion, wherein the recirculation region is more proximal to the closed housing end than the intermediate region;
• a fuel nozzle assembly including a fuel nozzle disposed at the closed end,
• an impingement cooling sleeve disposed in the compressed air passage surrounding the liner portion defining the combustion zone, the sleeve having a plurality of orifices sized and configured to impingement cool an outer surface of the liner portion with essentially all of the compressed air received at the housing inlet passing through the sleeve;
• a plurality of swirl vanes circumferentially disposed in the liner and configured to introduce a first portion of the compressed air from a region downstream of the impingement cooling sleeve into the recirculation region of the combustion zone in a swirling flow pattern;
• a plurality of intermediate holes circumferentially disposed in the liner and configured to introduce a second portion of the compressed air from the region downstream of the impingement cooling sleeve into the intermediate region of the combustion zone,
• a plurality of dilution openings circumferentially disposed in the liner and configured to introduce a third portion of the compressed air from the region downstream of the impingement cooling sleeve into the dilution zone,
• wherein an injection part of the remainder portion of the compressed air from the region downstream of the impingement cooling screen is channeled through the fuel nozzle assembly for mixing with the low calorific fuel to form a fuel spray which is injected into the combustion zone through the nozzle;
• wherein a primary combustion process occurring in the recirculation region of the combustion zone is stabilized by the first portion of compressed air introduced by the swirl vanes in a swirling flow pattern, and
• wherein a secondary combustion process occurring in the intermediate region of the combustion zone is effected by the second portion of the compressed air introduced to the intermediate region of the combustion zone through the intermediate holes downstream recirculation region.