Bio-syngas and Natural Gas Blended Fuel for Gas Turbines: A Computational Study

Abstract

Combined-cycle power plants (CCPPs) are crucial for the energy transition due to their ability to quickly adjust power output, compensating for renewable energy fluctuations. However, CCPPs face challenges such as limited natural gas and residual greenhouse gas emissions. Bio-syngas, an eco-friendly alternative from various sources, is emerging as a viable substitute. This study used computational fluid dynamics (CFD) simulations to the combustion performance and emissions of gas turbine combustion chambers with bio-syngas and natural gas mixtures. Three types of syngas and four syngas proportions were evaluated. Results show that increasing syngas proportion reduces combustion efficiency. The most notable decrease is observed in syngas 1, where the combustion efficiency drops from 99.21% to 97.56%. The flame structure shifts to the chamber center at lower syngas proportions and to the sides at higher proportions due to changes in mass flow rate. Lower syngas proportions enhance outlet uniformity, while higher proportions the pattern factor, potentially becoming unsafe for turbine entry. Emissions analysis indicates that higher syngas proportions increase CO2 and CO per heat input, while lower combustion temperatures reduce NOx production. The study concludes that existing turbines can use up to 20% syngas without modifications; beyond this, combustion chamber adjustments are needed.