Ingénierie et gestion industrielles

Simulation of the Effects of Turbine Exhaust Recirculation on the Composition of Flue Gas for a CO₂ Capture Unit

Abstract

Ahmed Mohamed Al Menhali, Abdulla Ali AL Marzooqi, Abdul Rahman Saleh Alameri, Abdulla Mohamed Al Ameri and Zin Eddine Dadach

For an effective CO₂ absorption by amines, the flue gas should contain at least 10% (mol.) of CO₂. Moreover, in order to avoid technical problems related to the oxidative degradation of amines, the flue gas should also contain less than 5% (mol.) of O₂. This paper presents preliminary calculations and simulation of the effects of Flue gas recirculation (FGR) ratios and excess air (EA) on the temperature and the concentration of CO₂ and O₂ in the exhaust gas of a natural-gas fired turbine. The results of the methodology utilized (preliminary calculations and simulation) indicate that, for a gas turbine that limits the temperature of the exhaust gas leaving the combustor at 1035°C, an excess air (EA) of 200% and a Flue Gas Recirculation (FGR) ratio of 0.65 are needed to fit the requirements of an effective absorption process by amines. For a turbine that allows temperatures as high as 1480°C, the operating parameters (EA=100% and FGR ratio of 0.4) will be selected.