300 Btu gas combustor development program. Phase I. Final report, August 1979

Abstract

Industrial turbines fired on medium heating value (MHV) gas (nominally 300 Btu/scf) synthesized from coal offer an attractive alternative means of producing electrical power in the future. Peak flame temperatures resulting from combustion of this MHV gas in conventional diffusion flame combustors may be comparable to those of natural gas, yielding undesirably high concentrations of NO/sub x/. The purpose of this program was to demonstrate a MHV gas turbine combustor capable of meeting Environmental Protection Agency (EPA) NO/sub x/ requirements without water injection. Program objectives were to design, fabricate, and test three MHV combustor configurations and to demonstrate NO/sub x/ emissions concentrations of 15 ppmv (dry basis) or less at a burner inlet pressure of 1.27 atms. The program goal of 15 ppmv corresponds to approximately 55 ppmv at engine pressures. Current EPA requirements are 75 ppmv. Design of the combustors was based on a lean-premix concept. By premixing fuel and air in lean proportions prior to combustion, flame temperatures, and thus NO/sub x/ formation, were controlled. Tests were conducted in a single-can combustor rig at simulated engine conditions ranging from 40 to 125% of engine baseload (74 MW). Measured data included inlet and exit temperatures, pressures, and emissions of more » NO/sub x/, CO, CO/sub 2/, O/sub 2/ and total (unburned) hydrocarbons. A conventional diffusion flame burner fired on natural gas was also tested to obtain baseline data. NO/sub x/ data were corrected to standard conditions as per EPA requirements for inlet pressure, percent O/sub 2/, and specific humidity. Rig data were analyzed to obtain performance parameters of combustion efficiency, burner pressure loss, and exit temperature pattern factor. Results show that all three combustors meet the NO/sub x/ goal, with corrected concentrations of 12 ppmv or less over the range of test conditions. « less