Fuel reformer device

Abstract

The present invention is directed to a fuel reformer device that produces a hydrogen rich gas from a hydrocarbon and steam. The steam reforming reaction that produces the hydrogen rich gas from the hydrocarbon and steam is endothermic. A known technique supplies heat required for the steam reforming reaction by an exothermic oxidation reaction proceeding in parallel with the steam reforming reaction. This known technique may, however, cause an excessive temperature rise in an area of the vigorous oxidation reaction in the fuel reformer device. A reformer unitincluding a Cu—Zn catalyst receives a supply of a crude fuel gas containing the air flown through a second fuel supply conduit. The crude fuel gas is subjected to the steam reforming reaction and the oxidation reaction proceeding inside the reformer unit. A resulting hydrogen rich gaseous fuel is discharged to a third fuel supply conduit. The reformer unitincludes an upper stream reaction unitand a lower stream reaction unit. Both the reaction unitsandhave honeycomb structures, wherein the total sectional area of the flow path in the upper stream reaction unitis made smaller than the total sectional area of the flow path in the lower stream reaction unit. This arrangement causes the gas flowing through the reformer unitto have the higher flow velocity on the upstream side than on the downstream side. The higher flow velocity on the upstream side extends the area of the vigorous oxidation reaction to the lower stream portion and enables the heat generated on the upstream side to be effectively transmitted to the lower stream portion. This arrangement thus effectively prevents an excessive temperature rise on the upstream side.