Fluidized bed combustion in high concentrations of O2 and CO2

Combustion using oxygen instead of air is a method under development in order to get high concentration of CO2 in flue gases to enable more efficient captire and further storage of CO2. High concentrations of O2 and CO2 have also other advantages; fuel power will rice, furnace dimensions will be smaller and faster load changes are possible. The greatest effects of CO2 and H2O in the operation are due to higher specific heats compared to nitrogen. In large boilers they contribute to the gas radiation. In addition, high CO2 and H2O concentrations promote internal gasification of particles to some extent especially due to higher particle temperature when O2 concentration is high. Fluidized bed combustion in high concentrations of O2 and CO2 is studied by measurements and modelling in bench and pilot scale fluidized bed reactors. Fuel reactivities obtained from the bench and pilot scale experiments can be applied to 1D and 3D CFD models to simulate the conditions in a large boiler. In addition, influences of different variables to the high oxygen combustion concept in CFB are studued.