Effect of fuel composition of LNG on the performances and operating characteristics of a gas turbine cycle

The effect of natural gas compositions on the thermodynamic performance characteristics of the single-shaft gas turbine cycle is analyzed in this study. The fuel characteristics are signified by H/C ratio and heating value, then the system are analyzed, and the full off-design analysis is performed by using TIT, TET, and power control. As the heating value of natural gas decreases, power output increases due to the increased mass flow passing through the turbine for all control methods. Additionally, regardless of the control method, the compressor surge margin is reduced and the turbine blade temperature is raised, making the gas turbine operation extremely vulnerable. Most parameters are sensitively affected by the HC ratio of fuel with TIT control. When the power control is used, gas turbine efficiency is reduced due to the increased operation of the compressor. The results are expressed by polynomial equations relative to each design value. In terms of the performance curves of the gas turbine cycle, the trends of most parameters accord with high H/C ratio and low heating value.