Preliminary calculations on post combustion carbon capture from gas turbines with flue gas recycle

Carbon capture is getting increased attention recently due to the fact that it seems to be the only answer to decrease emissions. Gas turbines exhaust have 3-5 % concentration of CO₂ which is very low to be captured by an amine carbon capture plant effectively. The amine based plants are most effective at around 10 - 15% CO₂ in the flue gas. In order to increase the concentration of CO₂ in the exhaust of the gas turbine, part of the exhaust gas needs to be recycled back to the air inlet. On reaching the concentration of CO₂ around 10% it can be fed to the amine capture plant for effective carbon capture. A 100 kWe (plus 150 kW hot water) CHP gas turbine Turbec T100 is installed at the Low Carbon Combustion Centre of the University of Sheffield. The turbine set up will be modified to make it CO₂ capture ready. The exhaust gases obtained will be piped to amine capture plant for testing capture efficiency. Preliminary calculations have been done and presented in this paper. The thermodynamic properties of CO ₂are different from nitrogen and will have an effect on compressor, combustor and turbine performance. Preliminary calculations of recycle ratios and other performance based parameters have been presented in this paper. This paper also covers the aspects of turbine set up machinery which needs to be modified and what kind of modifications may be needed.