Concept of hydrogen fired gas turbine cycle with exhaust gas recirculation: Assessment of combustion and emissions performance. (June 2015)

• Record Type: Journal Article
• Authors: Ditaranto, Mario; Li, Hailong; Løvås, Terese
• Is Part Of: International journal of greenhouse gas control. Volume 37(2015:Jun.)
• Page Start: 377
• Page End: 383
• Publication Date: 2015-06
• Subjects: Exhaust gas recirculation (EGR) -- Pre-combustion CO2 capture -- IGCC -- Hydrogen gas turbine -- NOx; Greenhouse gases -- Environmental aspects -- Periodicals; Air -- Purification -- Technological innovations -- Periodicals; Gaz à effet de serre -- Périodiques; Gaz à effet de serre -- Réduction -- Périodiques; Air -- Purification -- Technological innovations; Greenhouse gases -- Environmental aspects; Periodicals; 363.73874605
• DOI: 10.1016/j.ijggc.2015.04.004
• Languages: English
• ISSNs: 1750-5836

Abstract

Graphical abstract: Highlights: Applying EGR to a H2 -fired gas turbine inherently limits NOx formation. High EGR rates can be achieved with hydrogen rich fuels without impeding stability. Nitrogen dilution of H2 fuels and consequent efficiency penalty can be avoided. Pre-combustion CO2 capture and IGCC power plants can benefit from the EGR concept. Abstract: A novel gas turbine cycle concept applicable to power plants with pre-combustion CO2 capture or integrated gasification combined cycle (IGCC) is presented. These power plants use a hydrogen rich fuel with high reactive combustion properties which makes fuel dilution necessary to achieve low NOx emissions. The proposed novel gas turbine arrangement is set up as to avoid both fuel dilution and its consequent efficiency penalty, and breakthrough in low NOx combustion technology. In this concept, a high exhaust gas recirculation (EGR) rate is applied in order to generate an oxygen depleted working fluid entering the combustor, enough to reduce the high reactivity of hydrogen rich fuels. As a result, the combustion temperature in this environment is inherently limited, thus, keeping NOx formation rate low. A first order assessment of the combustion characteristics under such gas turbine operating conditions is made in the light of a numerical analysis of stability and NOx emissions potential. Both diffusion and premixed types combustor are considered according to the selected EGR rate. It is first shown that the flame stability could be maintained at EGR rates well above the maximum EGR limit found in conventional natural gas fired gas turbines. The study further shows that at these high EGR rates, considerable reductions in NOx emissions can be expected. The conclusion of this first order analysis is that there is a true potential in reducing the efficiency penalty induced by diluting the fuel in power plants with pre-combustion CO2 capture.