Biomass Combustion with in Situ CO2 Capture by CaO. II. Experimental Results

Experiments to test the concept of biomass combustion with in situ CO2 capture by CaO have been conducted in a 30 kW interconnected fluidized-bed test facility. The CO2 capture efficiency in a combustor-carbonator reactor was measured over a range of operating conditions, using three biomass feeds (olive pits, saw dust, and pellets). Overall CO2 capture efficiencies higher than 80% were achieved with sufficiently high solids circulation rates of CaO and solids inventories in the combustor-carbonator. Emissions of CO and CH4 were detected during the experiments, possibly because of pulse feeding and/or an inappropriate air/fuel mixture. The application of a simple reactor model for combining biomass combustion and CO2 capture allows an effectiveness factor of 0.74 to be derived for all of the experiments. This could be valuable for scaling-up purposes.