EFFECT OF PRESSURE ON EMISSION CHARACTERISTICS IN LEG-FUELED 1500-DEGREES-C-CLASS GAS-TURBINE

Developing integrated coal gasification combined cycle (IGCC) systems ensures cost-effective and environmentally sound options for supplying future power generation needs. In order to enhance thermal efficiency of IGCC and to reduce NOx emission, a 1500 degrees C-class gas turbin e combustor for IGCC was designed, tested, and the performance of the combustor was evaluated under pressurized conditions. The designed com bustor had the following three characteristics: (1) in order to assure the stable stalled at the entrance of the combustor; (2) to reduce fu el NOx emission that was combustion burning low-Btu gas (LBG), an auxi liary combustion chamber was in-produced from the ammonia (NH3) in the fuel, the rich-lean combustion method was introduced; and (3) to comp ensate for the declined cooling-air associated with the higher tempera ture of the gas turbine, the tested combustor was equipped with a dual -structure transition piece so that the cooling air in the transition piece can be recycled to cool down the combustor liner wall. As a resu lt of combustor tests, it is confirmed that CO emission is less than 2 0 ppm, the conversion rate of NH3 which contains about 1000 ppm in the coal gasified fuel to NOx shows 40 percent or below, and the liner wa ll temperature remained below almost 850 degrees C under high pressure (1.4 MPa), rated load condition.