An oxy-fuel combustion boiler for high concentration of carbon dioxide is provided to prevent the condensation of water in re-circulated exhaust gas and to prevent the damage of an exhaust gas recirculation duct and a burner and combustion troubles due to condensed water by make re-circulated exhaust gas re-supplied to a boiler exchange heat with exhaust gas discharged from a boiler and raising the temperature of exhaust gas above the saturation temperature of water. An oxy-fuel combustion boiler for high concentration of carbon dioxide comprises a boiler(10) burning fuel and an oxidizer to heat water and discharging exhaust gas to an exhaust pipe(12), a liquid oxygen tank(40) supplying liquid oxygen, an atmospheric liquid oxygen converter(50) connected with the liquid oxygen tank to supply heat to liquid oxygen by air in the atmosphere and to evaporate the liquid oxygen, a CO2 liquefier(30) liquefying high-concentration carbon dioxide among exhaust gas discharged from the boiler, a fuel economizer(20) making the high-temperature exhaust gas discharged from the boiler exchange heat with the water supplied to the boiler, a re-circulated exhaust gas heater(90) getting a supply of a portion of the exhaust gas discharged from the boiler to the re-circulated exhaust gas along a recirculation pipe branched from an exhaust pipe by a ventilator and exchanging heat with the high-temperature exhaust gas discharged from the boiler to heat the re-circulated exhaust gas, and a mixer(60) getting a supply of the re-circulated exhaust gas heat-exchanged in the re-circulated exhaust gas heater and the oxygen evaporated in the liquid oxygen converter and mixing to be used as an oxidizer.
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