An oxygen transport reactor for boiler furnaces and gas turbine combustors that utilizes a liquid fuel that is oxidized as a gaseous fuel in a membrane reactor. A liquid fuel is introduced by vaporizing the fuel inside a porous pipe surrounded by an annulus reaction zone which is surrounded by an annulus air zone. An oxygen transport membrane separates the annulus reaction zone containing the porous vaporized fuel and sweeping CO2 from the air feed side zone. Oxygen is transported from the outer annulus through the membrane to the annulus reaction zone containing the vaporized fuel and sweeping CO2. Fuel is first cracked to very small droplets in the intake fuel atomizer utilizing part of the intake CO2 then completely vaporized inside the porous pipe utilizing the heat coming from the surrounding reaction zone. The oxygen transport reactor is applicable for carbon free boiler furnaces and gas turbine combustors which utilize oxygen transport reactors for combined oxygen separation and combustion.