Abstract: Provided are a method and an apparatus of controlling exhaust gas in an oxyfuel combustion boiler which can attain stable combustion of the boiler while an amount of unburned combustibles and a NOx density in exhaust gas are maintained in their allowable ranges. A rate of supply of directly supplied oxygen to burners 6 to a total amount of oxygen produced by an air separation unit 18 is regulated in an operating range where the NOx density in the exhaust gas is below a NOx limit value and the amount of unburned combustibles in the exhaust gas is blow an unburned combustible limit value to thereby attain stable combustion of the oxyfuel combustion boiler.

Abstract: A method and an apparatus of controlling combustion in an oxyfuel combustion boiler are provided which ensure a sufficient furnace heat absorption through prevention of lowering of flame temperature, enabling oxyfuel combustion operations to be performed in a stable manner. A boiler-brought-in oxygen density which is an oxygen density for a total amount of gases introduced into a coal burning boiler is calculated and a flow rate of total recirculating gases is controlled such that the boiler-brought-in oxygen density falls within a predetermined range.

Abstract: Provided are a method and an apparatus of controlling an oxygen supply in an oxyfuel combustion boiler capable of attaining stable oxyfuel combustion even when properties of coal are changed. A boiler-brought-in oxygen density is obtained when coal with a fuel ratio measured by fuel measuring means 39 is burned stably with oxygen in a boiler 4 so that a relationship between the fuel ratio and/or carbon content of the coal and the boiler-brought-in oxygen density is obtained and inputted in advance into the controller. When the coal is changed to the new kind of coal, a total amount of gases recirculated is regulated such that a boiler-brought-in oxygen density becomes accordance with a fuel ratio and/or a carbon content which is measured in advance for the new kind of coal.

Abstract: Provided are fuel feed means 3, an air separation unit 6 air feed means 7, a combustion furnace 11 with a burner 9 for combustion, an exhaust gas line 14 for leading an exhaust gas from the combustion furnace 11 to outside of the combustion furnace 11, exhaust gas treatment means 20a and 20b included in the exhaust gas line 14, and a recirculation line 15 for circulating a portion of the exhaust gas at least exhaust gas treatment means 20a and 20b for recirculation of a portion of the exhaust gas at least dust-removed by the exhaust gas treatment means 20a and 20b to the burner. Further provided are exhaust gas capture means 18 for taking out carbon dioxide gas from a remaining non-recirculating exhaust gas, and carbon dioxide gas feed means 33, 40 and 46 for introducing carbon dioxide gas to equipments 10, 20a and 20b of the oxyfuel combustion boiler facility.

Abstract: An apparatus of controlling oxygen supply for a boiler having wind boxes 2a and 2b arranged on left and right of a boiler body 1 is configured to control supply balance of oxygen by adjusting oxygen supply opening degrees of the left and right oxygen distribution dampers 15a and 15b in accordance with a oxygen supply flow rate and left and right actually measured oxygen concentrations when controlling the oxygen supply amounts and to control the exhaust gas flow rates by correcting an exhaust gas flow rate set value corresponding to a boiler load demand in accordance with an oxygen concentration set value corresponding to a boiler load demand, left and right actually measured exhaust gas flow rates and left and right actually measured oxygen concentrations and adjusting left and right exhaust gas introduction opening degrees of the left and right exhaust gas introduction dampers 8a and 8b when controlling the exhaust gas flow rates.