Re-sizing of a natural gas fired two-shaft gas turbine for low calorific gas operation
Gas turbine systems are predominantly designed to be fuelled with gaseous fuels within a limited Wobbe index range (typically HHV=45-55 MJ/Nm3 or 1200-1480 Btu/scf). When low calorific fuel gases are fired, the engine will be forced to operate outside its design envelope. The added mass flow will typically raise the cycle pressure ratio and in two-shaft designs also raise the gas generator shaft s