Abstract
A new burner configuration for a compact fuel-cell reformer with a high-temperature air combustion concept was numerically studied. The burner was designed for a 40 $Nm^3/hr$ hydrogen-generated reformer using natural gas-steam reforming method. In order to satisfy the primary requirements for designing a reformer burner (uniform distribution of temperature along the fuel processor walls and minimum heat losses from the reformer), the features of the present burner configuration included 1) a self-regenerative burner for an exhaust-gas-recirculation to apply for the high-temperature air combustion concept, and 2) an annular-type shield for protecting direct contact of flame with the processor walls. For the injection velocities of the recirculated gas of 0.6-2.4 m/s, the recirculated gas temperature of 1000 K, and the recirculated oxygen mole fraction of 4%, the temperature distributions along the processor walls were found uniform within 100 K variation. Thus, the present burner configuration satisfied the requirement for reducing temperature gradients along the processor walls, and consequently demonstrated that the high-temperature air combustion concept could be applied to the practical fuel reformers for use of fuel cells. The uniformity of temperature distribution is enhanced as the amount of the recirculated gas increases.
