Gas turbine engine configurations for power generation cycles having CO 2 sequestration

Abstract

Abstract

Atmospheric CO₂ is believed to cause over 60 per cent of the present ‘greenhouse gas’ global warming effect; its concentration is increasing, due partly to the growth in power production plants that burn hydrocarbon fuels. Gas turbines burning natural gas are used increasingly in new power producing plant. Sequestering the CO₂ from the entire exhaust of a gas turbine requires large, expensive plant. Some alternative options for eliminating CO₂ emissions are explored herein. Only the engine implications are examined in detail. One option is to burn hydrogen-rich fuel that is carbon-free; manufacture of such fuels must include sequestration of any CO₂. Another option is to use closed-cycle plants fuelled by hydrocarbons, having CO₂ as the working fluid, with exhaust sequestration of CO₂. Sequestration in this case needs much smaller plant because only a small fraction of the exhaust is processed. Both options have already been explored for single-shaft, synchronous engines. This paper presents a study of possible free power turbine engines. The engine hardware changes needed when switching from natural gas to hydrogen-rich fuel are mainly the combustor and the control system, for both configurations. The hardware and performance changes from switching from air to a CO₂-rich working fluid are, for both configurations. considerable.