Oxyfuel boiler system and method of controlling the same

摘要

The oxyfuel boiler system comprises: an oxygen generator 10; a coal mill 11; a burner 12 to burn pulverized coal; an after-gas port 13 to which oxygen generated at the oxygen generator 10 is supplied; a boiler 1 provided with the burner 12 and the after-gas port 13 on its wall; a flue 20 introducing combustion exhaust gas from the boiler 1 to the outside; a recirculation gas supply pipe 14 having an exhaust gas tapping port 22 in the midway of the flue 20 and supplying recirculation exhaust gas to the coal mill 11, the burner 12, and the after gas port 13; and an oxygen supply pipe 16 supplying oxygen from the oxygen generator 10 to the burner 12 and the after-gas port 13, wherein the exhaust gas tapping port 22 is disposed downstream of a dry dust-removing apparatus 4 arranged in the flue 20, and there is provided an oxygen controlling apparatus 25 for making a concentration of oxygen to be supplied to the after-gas port 13 lower than that of oxygen to be supplied to the burner 12.