Oxy-Fuel Firing Technology for Power Generation

In order to generate pure streams of CO₂ suitable for sequestration/storage, various routes are possible, involving either precombustion strategies such as the use of gasification technology combined with shift reactors to produce H₂ or alternatively post-combustion strategies such as CO₂ scrubbing with, for example, amine-based carriers. One of the more direct approaches is to carry out the combustion in pure or nearly pure oxygen-oxy-fuel combustion to produce primarily CO₂ and H₂O in the combustion gases, resulting in almost complete CO₂ capture. Until recently, the primary avenue for deploying this technology was with conventional pulverized fuel-fired boilers, and there is already one large demonstration plant operating in Europe with more being planned in the future. However, more recently oxy-fired fluidized bed combustion (FBC) has also become increasingly important as a potential technology, offering as it does fuel flexibility and the possibility of firing local or indigenous fuels, including biomass in a CO₂-neutral manner. Both oxy-fuel combustion technologies have been examined here, considering factors such as their economics and potential for improvement, as well as challenges to the technology, including the need to generate CO₂ streams of suitable purity for pipeline transport to available sequestration sites. Finally, the emission issues for both classes of the technology are discussed.