Evaluation of a pre-combustion capture cycle based on hydrogen fired gas turbine with exhaust gas recirculation (EGR)

Abstract

Pre-combustion capture technology is a promising route to power generation with CO2 free emissions, by transforming the fossil hydrocarbon fuel into a hydrogen rich fuel with near zero Carbon containing species. This gaseous fuel also allows to use a high efficiency gas turbine into a coal based power plant. The gas turbine combustor however has to meet the challenge of high temperature flame responsible for unacceptable NOx emissions, and a highly reacting fuel impeding the use of conventional dry low NOx combustion technologies. The actual solution to this problem is to dilute the hydrogen fuel with up to 50% Nitrogen. This paper presents a concept where the exhaust gas of the gas turbine is recirculated (EGR) such as to deplete the air of oxygen to produce a low temperature combustion with undiluted hydrogen fuel while flame stability is still ensured by the highly reactive properties of hydrogen. The study compares the concept with a cycle using Selective Catalytic Reduction for NOx control.