Combustion system and operation method thereof

Comprises a burner 19 for burning pulverized coal in a combustion gas obtained by mixing the exhaust gas and the oxygen-rich gas burning pulverized coal burner 19 includes a fuel nozzle 25 for burning the pulverized coal supplied is entrained in a carrier gas, comprising a combustion gas nozzle 27 for supplying additional combustion gases 26 to the fuel nozzle 25, the combustion gas nozzle 29 for supplying the combustion gases 28, 30 on the outside of the fuel nozzle 25, fuel nozzles 25, oxygen-enriched into the exhaust gas conveying gas produced by adding gas is supplied, the combustion gas nozzle 29 and the combustion gas nozzle 27, the combustion gas produced by the addition of oxygen rich gas is supplied to the exhaust gas, the supply amount and the oxygen concentration in the carrier gas, the supply amount and the oxygen concentration of the additional combustion gas 26, a supply amount and the oxygen concentration of the combustion gases 28, 30, adjustably formed.