Woody Biomass Cogeneration with Hot Air Turbine: Application to a Wood Pellet Production Unit in Algeria

In this paper, the performance of a hot air turbine operating in an industrial combined heat and power (CHP) cogeneration is investigated, electrical and thermal energy supplied are intended for a pellet production unit. This unit is powered by Eucalyptus residue at 50% moisture content recovered from a forest located in El Taref, north-east of Algeria. The results show that when the air temperature at the boiler inlet Te exceeds 100 degree C, an excess air ratio, alpha, above 90% is required to maintain the flame temperature below 1200 K. Based on this, the parameters were set to alpha = 80% and Te = 100 degree C, resulting in a flame temperature of 1192K. The turbine inlet temperature T3, which must remain below the flame temperature, was fixed at 1140K. Once these conditions were established, the compression ratio maximizing the overall efficiency was determined to be around 8, yielding a cogeneration efficiency of 53%, with an electrical efficiency of 20% and a thermal efficiency of 33%.