An ALSTOM Vision of Future CFB Technology Based Power Plant Concepts

ALSTOM is actively working to develop circulating fluidized bed (CFB) based technologies to continue to reduce costs and mitigate CO₂. Advanced ALSTOM concepts include “the oxygen-fired CFB,” which uses pure oxygen plus recirculated flue gas (mainly CO₂) as a combustion medium, resulting in a flue gas stream with a high CO₂ concentration. Consequently, CO₂ can be separated from the flue gas stream relatively easily. As such, this technology is geared toward CO₂ mitigation. Another advancement, “the circulating moving bed (CMB^TM)” system, uses a novel heat exchanger design that heats the energy cycle working fluid to the high temperature levels required for advanced power generation systems. The CMB^TM combustion system is also an enabling technology for hydrogen production and CO₂ capture from combustion systems utilizing innovative chemical looping gasification and syngas decarbonization. Chemical looping is another development path towards CO₂ mitigation. In ALSTOM’s processes, oxygen (from air) is transported by a solid oxygen carrier for combustion or gasification of the fuel. CO₂ is captured in a separate chemical loop in the gasification process. The process can be used to produce nearly pure CO₂ and steam for a Rankine cycle; or synthesis gas or hydrogen with CO₂ capture for IGCC’s, fuel cells, or industrial use. This paper will discuss ALSTOM’s latest work and the technical and economic implications of these advanced CFB-based systems. These advanced power generation units can be built from proven fluid bed design features and systems and the same processes supporting current-state technology enable rational development of future-state power generation and CO₂ capture.