Abstract: Carbon monoxide contained in reformate gas is removed by a preferential oxidation reaction in a catalyst, two preferential oxidation reactors (20A, 20B) being disposed in series. Valves (7, 8) supply air containing oxygen as an oxidizing agent individually to these preferential oxidation reactors (20A, 20B). Temperature sensors (9, 10) detect the catalyst temperatures of the preferential oxidation reactors (20A, 20B), and a controller (5), by adjusting the flow rate of the valves (7, 8) based on the detected temperatures, maximizes the carbon monoxide removal performance of the preferential oxidation reactors (20A, 20B), while preventing excessive catalyst temperature rise.

Abstract: A fuel cell stack (1) comprises a reactive gas passage (115, 1c, 116, 1a) and a water passage (117, 1b) substantially parallel thereto, and a reactive gas is humidified by water permeating from the water passage (117, 1b) through a porous member (112a, 112c). The pressure reduction amounts in the reactive gas passage (115, 1c, 116, 1a) and the water passage (117, 1b) are respectively calculated based on the power generation load of the stack (1). From the pressure reduction amounts in the water passage (117, 1b) and the reactive gas passage (115, 1c, 116, 1a), the pressure of the reactive gas supplied to the reactive gas passage (115, 1c, 116, 1a) is controlled such that the difference in pressure between the reactive gas passage (115, 1c, 116, 1a) and the water passage (117, 1b) is within a predetermined range, whereby the reactive gas is humidified in a desirable state.

Abstract: A reaction state at an upstream portion of the catalyst unit in which a partial oxidation reaction occurs is detected by a first reaction state detector, and a reforming reaction state in the whole of the catalyst unit composed of a catalyst for promoting a steam reforming reaction and a catalyst for promoting a partial oxidation reaction is detected by a second reaction state detector. Based on a reaction state detected by the second reaction state detector, a first corrector corrects feed amounts of raw fuel gas and oxidation gas, which are supplied to the catalyst unit, and a second corrector corrects a feed amount of the oxidation gas supplied to the catalyst unit and/or a feed timing thereof, based on the reaction state detected by the first reaction state detector.

Abstract: Carbon monoxide contained in reformate gas is removed by a preferential oxidation reaction in a catalyst, two preferential oxidation reactors (20A, 20B) being disposed in series. Valves (7, 8) supply air containing oxygen as an oxidizing agent individually to these preferential oxidation reactors (20A, 20B). Temperature sensors (9, 10) detect the catalyst temperatures of the preferential oxidation reactors (20A, 20B), and a controller (5), by adjusting the flow rate of the valves (7, 8) based on the detected temperatures, maximizes the carbon monoxide removal performance of the preferential oxidation reactors (20A, 20B), while preventing excessive catalyst temperature rise.

Abstract: A reaction state at an upstream portion of the catalyst unit in which a partial oxidation reaction occurs is detected by a first reaction state detector, and a reforming reaction state in the whole of the catalyst unit composed of a catalyst for promoting a steam reforming reaction and a catalyst for promoting a partial oxidation reaction is detected by a second reaction state detector. Based on a reaction state detected by the second reaction state detector, a first corrector corrects feed amounts of raw fuel gas and oxidation gas, which are supplied to the catalyst unit, and a second corrector corrects a feed amount of the oxidation gas supplied to the catalyst unit and/or a feed timing thereof based on the reaction state detected by the first reaction state detector.