Performance analysis of the micro gas turbine Turbec T100 with a new FLOX-combustion system for low calorific fuels

Abstract

This paper presents the first combustion system, which has been designed for the use of biomass derived product gases in micro gas turbines. The operating performance of the combustion system and of the micro gas turbine Turbec T100 was analyzed experimentally with synthetically mixed fuel compositions. Reliable start-up procedures and steady-state operation were observed. The Turbec T100 reached an electrical power output of 50 to 100kWel with a lower heating value of 5.0MJ/kg. Compared to natural gas, the electrical power output was noticeably higher at constant turbine speeds. Therefore, operation was limited by the power electronic at low speeds, while a second limitation was compressor surging at high speeds. To avoid surging, the turbine outlet temperature had to be reduced at turbine speeds between 64,400rpm and its maximum of 70,000rpm. The pressure losses across the FLOX-combustion chamber remained below 4%, which corresponds to a reduction of 30% compared to the Turbec combustion chamber fired with natural gas. Low pollutant emissions, i.e. CO<30ppm, NOx<6ppm and unburnt hydrocarbons <1ppm, were obtained over the whole operating range. Further optimization potential of the Turbec T100 was analyzed numerically. Neglecting compressor surging and the limitations of the power electronic, the numerical simulations predicted a maximum power output of 137kWel. The ability of the micro gas turbine to run with low calorific fuels is demonstrated and optimization potential is specified.