Micro Gas Turbine Operation with Biomass Producer Gas and Mixtures of Biomass Producer Gas and Natural Gas

摘要

We report the performance of a commercial recuperated micro gas turbine on biomass producer gas and mixtures of biomass producer gas with natural gas. The biomass producer gas, obtained by gasification at 850 ℃ with air at atmospheric pressure, contains about 7% H_2,17% CO, 15% CO_2,4% CH_4, 2% other hydrocarbons, 2% H_2O, and a balance of N_2 and Ar from air. It has a net heating value of about 6 MJ/(N m~3). The micro gas turbine delivers full power (30 kW_e) on gas mixtures with a net heating value of at least 15 MJ/(N m~3). For gas of lower heating value, the maximum fuel gas flow allowed by the fuel control unit limits the attainable power. At reduced power, the lower limit for stable operation is a net heating value of about 8 MJ/(N m~3). The gross efficiency of the micro gas turbine depends on the output power but not on the gas heating value, within our estimated measurement accuracy of about 2%. Above 70% of full power, NO emission is 5 times lower than that allowed by Dutch or German legislation, and CO emission is 40 times lower. Emissions of CO, unburned hydrocarbons, and NO are over 200 times, 15 times, and 3 times lower than those of a gas engine of similar size, operating on the same biomass producer gas. At partial load below 70% of full power, the micro gas turbine burner switches to a different operating mode that produces higher CO and NO levels. The CO emission remains far below that of the gas engine but exceeds the German limit during operation on the producer gas mixtures. The NO emission becomes similar to the emission of the gas engine and close to the legal limits.