An industrial gas turbine combustor has been developed which is capable of operating over the gas turbine load range on a variety of coal-derived low Btu gases as well as No. 2 distillate fuel. At gas turbine cycle conditions using simulated coal-derived low Btu gas, CO emissions and combustor blowout characteristics are comparable to those obtained with current product line combustors burning No. 2 distillate. The results of laboratory single burner combustion tests with simulated low Btu gases, ranging in heating value from 809 to 1369 kcal/NM3 (91–154 Btu/scf), are described. Parametric studies were also conducted in which the moisture content of the fuel (at constant volumetric lower heating value) and heating value were varied. The results of these tests are compared with those obtained with a conventional constant cross-sectional area combustor and those of other investigators.

General Electric Company is developing and testing low heating value fuel gas turbine combustors for use in integrated gasification combined cycle power generation systems. This paper presents the results of a series of combustion tests conducted at the pilot scale coal gasification and high temperature desulfurization system located at GE Corporate Research and Development in Schenectady, New York. Tests were performed in a modified GE MS6000 combustor liner operating at a pressure of 10 bar and over a wide load range (combustor exit temperatures from 760 to 1400°C). The primary objective of these tests was to compare and contrast the performance (emissions, flame stability, and combustor liner temperatures) of six different low heating value fuel nozzle designs, representing three distinct nozzle concepts. With 2200 to 4600 ppmv NH3 in the fuel, the conversion of fuel NH3 to NOx was roughly independent of fuel nozzle type, and ranged from about 70% at low combustor exit temperatures to about 20% at high combustor exit temperatures. For all of the fuel nozzles, CO emissions were typically less than 5 ppmv (on a dry, 15% O2 basis) at combustor exit temperatures greater than 980°C. Significant differences in CO emissions were observed at lower combustor exit temperatures. Some differences in liner temperatures and flame stability were also observed with the different nozzles. In general, nozzles which produced lower CO emissions and greater flame stability had higher fuel swirl angles and resulted in higher combustor liner temperatures. The nozzle with the best overall performance (consisting of concentric axial air and fuel swirlers and an air cooled mixing cup) has been selected for use at a commercial site.

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The advent of higher fuel prices and operational costs associated with energy production have had a profound impact on the application of the gas turbine as a prime mover. This paper describes an extensive program carried out by the General Electric Company to demonstrate the ability of both the heavy-duty and aircraft-derivative gas turbines to operate satisfactorily while burning a wide range of lower heating value fuels, typical of industrial process or gas conditioning plants. Analytical predictions of flammability limit changes due to fuel composition variations, and combustion inlet air temperature effects are compared with small scale atmospheric burner tests. Finally, full scale single burner and sector test results are presented which demonstrate the capability of present generation combustion systems to operate on lower heating value fuels.