Optimizing the bio/natural gas ratio in a dual-fuel gas turbine (DFGT) through energy-economic, environmental, and renewability analyses

Today, considerable attention is given to the use of biofuels due to decreasing fossil fuels and increasing environmental problems. Biogas is a type of biofuels that is renewable in nature and also contains less amount of carbon than most fossil fuels. However, due to the high cost of investment on biogas plants, as well as the unstable and unreliable nature of its production, optimal design of a reliable and cost-effective system for biofuel generation is essential for different nature and constituents of biofuels. In this study, a dual-fuel gas turbine, in which a mixture of biogas and natural gas is the combustion fuel, is presented. The proposed system was analyzed based on the energy-economic, environmental, and renewability analyses. Moreover, scores of these parameters that varied within a range from 0 to 1 were defined. Indeed, raising the biogas-to-natural gas ratio (BNR) enhanced scores associated with renewability, CH4, and NOx emissions, whereas it decreased the score of fuel cost, CO, and CO2 emissions. Then, for making a quantitative comparison between various BNRs, a ranking function was presented based on energy-economic, environmental, and renewability analyses. Finally, considering the maximum value of the ranking function, the BNR was optimized at 0.31.