Evaluation of ethanol as a fuel for gas turbines

In this paper, the results of the evaluation of using ethanol in a GE 61B gas turbine are presented. For better understanding, combustion analysis for natural gas was performed as a comparison point, calculating fuel and air requirements at the entrance and exit of the combustion chamber, obtaining the principal emissions for both fuels at different temperatures and relationships air-fuel. Using design data taken from the manufacturer website, the four main processes of a complete Joule-Brayton cycle were calculated. In that way, the results were used as a thermodynamic basis in this work. Focus on the combustion turbine, setting the temperature at the entrance of the combustion chamber and varying the temperature at turbine inlet. Afterward, using the temperatures resulted by the calculations, stoichiometric air-fuel ratio and mole fractions were found. Finally, varying air-fuel ratio at diverse mixtures, there were obtained the emissions for both fuels. As results, there were obtained the fuel requirements for natural gas and ethanol, finding that for ethanol, due to its lower calorific value, the amount of fuel is higher in order to obtain the required temperature. In terms of emissions, there was no convincing evidence that ethanol represents a minor emission source than natural gas; therefore, it could be a good substitute of natural gas in those countries were ethanol is produced.