Patent ID: 8789479

Claim:
An oxygen mixer for an oxygen combustion boiler wherein circulating exhaust gas is heated by a preheater and mixed gas resulting from mixture of oxygen with said circulating exhaust gas is guided to a boiler furnace through a combustion gas duct with bends, said oxygen mixer comprising: an oxygen injection nozzle arranged at an upstream one of the bends in said combustion gas duct closest to the preheater, said oxygen injection nozzle having a plurality of injection ports for injecting the oxygen into the circulating exhaust gas, wherein said oxygen injection nozzle is passed from above into the combustion gas duct, wherein all the injection ports of said oxygen injection nozzle are opened at positions clear of any eddy produced by the circulating exhaust gas due to the bends of the combustion gas duct, and wherein a tip injection port is arranged on a downstream end of the oxygen injection nozzle to inject minute particles intruded in the oxygen injection nozzle outside of the oxygen injection nozzle.