ABSTRACT
A 0.5 MWth pulverized fuel combustion facility was modified and retrofitted for operation under oxyfuel conditions within the EU project ENCAP. The facility was tested towards safe handling and continuous operation, and optimised towards minimum air in-leakage. Combustion tests were performed with Lausitz lignite under both air and oxyfuel conditions including (wet) flue-gas recirculation. This paper describes experience made when operating the facility continuously under oxyfuel conditions with a global O₂ concentration in the combustion chamber of 27% on dry basis and under re-circulating conditions. The CO₂ share in the flue-gas was enriched to levels above 90 vol.-%dry with O₂, excess concentrations of 4–5 vol.-%dry. Switching from once-through combustion to re-circulation mode was tested and CO2 enrichment history was investigated. Fuel characterisation regarding behaviour of gas emissions and correlation with air and oxyfuel conditions was performed.