Design and operation assessment of an oxyfuel fluidized bed combustor

Oxyfuel combustion is a promising alternative for CO2 capture. While this has been proven in pulverized fuel (PF) burners, research in fluidized bed (FB) reactors is still scarce. Our work aims to increase the knowledge about this technology. To this purpose, a 95 kWth FB oxyfuel combustion test rig has been erected. Its main characteristics are described in this paper, giving detailed information on the subsystems: the FB reactor, the fuel and oxidant supplies, and ancillaries. Plant flexibility is emphasized. It allows to operate under different CO2/O2 ratios, and to recycle CO2 from the flue gases. Both the processes design and monitoring are supported by simulations that have been validated against experimental data, regarding fluid dynamics, combustion, and heat transfer. Finally, the performance of the facility has been tested both with coal alone and blended with biomass. CO2 concentrations over 90% (dry basis) in the flue gases have been obtained. Comparison of air and oxygen combustion tests and operational recommendations are discussed, confirming the feasibility of the FB oxyfuel technology for CO2 capture purposes.