Patent DE-102008024674-A1 (DE)
Title: Exhaust gas-fuel reformer-fuel cells combination for stop-start cycles in motor vehicles, comprises reformer-reactor, shift reactor, turbine wheel of radially acting fresh-air loader, auxiliary heating tube, and thermal insulator
Inventor: WEBER ERHARD
IPC: C01B3/02
Filed: 2008-05-21
Abstract: The exhaust gas-fuel reformer-fuel cells combination comprises a reformer-reactor (3), a shift reactor, a turbine wheel of a radially acting fresh-air loader, whose radial turbine blades are raised with the turbine wheel outwardly and/or inwardly on a common rotor, inserted into a combustion engine-exhaust gas or in reformer reactor and/or shift reactor-remaining gas stream, an auxiliary heating tube inserted by loading fuel or air for heating the combustion engine of the exhaust gas (1) before the reformer reactor and fuel cell combination, and a thermal insulator. The exhaust gas-fuel reformer-fuel cells combination comprises a reformer-reactor (3), a shift reactor, a turbine wheel of a radially acting fresh-air loader, whose radial turbine blades are raised with the turbine wheel outwardly and/or inwardly on a common rotor, inserted into a combustion engine-exhaust gas or in reformer reactor and/or shift reactor-remaining gas stream, an auxiliary heating tube inserted by loading fuel or air for heating the combustion engine of the exhaust gas (1) before the reformer reactor and fuel cell combination, and a thermal insulator provided around the reformer reactor, fuel cell (10) and the shift reactor. The thermal energy contained in the exhaust gas is used for heating the reactor (RR) of the reformer and the fuel cell (BZ) at respective operating temperatures. A pre-heated hydrocarbon-containing fuel gas is added as buffer gas and transport gas to the exhaust gas and endothermally reacts to hydrogen (H 2), carbon monoxide (CO) and carbon dioxide (CO 2) with the water steam H 2Og contained or additionally added in the exhaust gas under the use of the thermal energy delivered in the exhaust gas and recycled by the fuel cell and the remaining chemical energy of the exhaust gas. The reaction gas such as H 2, CO and CO 2is supplied directly or only H 2to the fuel cell of cathodic or anodic atmospheric oxygen over a hydrogen separator. The cylindrical entire-fuel cell is composed of segmented solid oxide individual-fuel cells, which consist of an internal carrier layer, a cathode layer, an electrolyte layer and an anode layer, where all the layers are sintered with one another in series. The solid oxide individual-fuel cells are individually arranged in pairs or triples part shells on cylinder, which are densely sintered to two separated biconcentric helix windings. The interior of the exhaust gas fuel tube of the reactor is equipped with deviating sections (33) and is opened to the cathodic inner helix winding over a radial slit opening, where the cathodic inner helix winding is formed together as reactor. The other anodic helix winding of the cylinder front side is densely sintered with an air supply pipe. The cathodic helix winding ends in a sintered pipe for the reception of the heated fuel remaining gases, which is fed back into the interior of the reactor tube over an exhaust gas inlet orifice, which is formed as jet pump. The anodic helix winding ends in a residual air of delivery pipe, which is sintered to gas-tight ceramic layer of the fuel cell. The center curvature of the cylinders part shells and the thicknesses of the fuel cell layers and the carrier layer are selected, so that the expansions of the layers with different temperatures compensate themselves over their lengths. The individual fuel cell is again segmented part shell webs in cylinder. The webs are separated by a peripheral joint, in which the layer converges the electrolyte or the electrolyte is replaced by a thin gas-tight ceramic insulating layer with expansion coefficient. The individual fuel cells overlap or interlock the part shells at the joints, are gas-tightly sintered with an insulated ceramic web with expansion coefficient and are connected in series by a nickel flag. The fuel cell with integrated reactor consists of rectangular surfaces superimposed on each other in the form of a double-helix made of two polygon-coils, in whose center the reactor internal tube and the air supply pipe are enclosed. The elongated fuel cell rectangular surfaces are subdivided into narrower single fuel cell segment with expansion joints. The reformer gas is supplied to the shift reactor after the reformer reactor for completely converting the carbon monoxide by additionally admixing evaporated and preheated water steam to carbon dioxide under further production of hydrogen. The hydrogen developed in the reformer and shift reactors is separated from the reformer gas and the shift gas by a hydrogen permeable separating device and then supplied over a conveying pump of the fuel cell. Only the shift reactor contains the hydrogen separating device and the separated hydrogen gas of the solid oxide fuel cell head is supplied to the combustion gas or cathodically supplied as combustion gas to a medium-temperature additional-fuel cell. The hydrogen separating device consists of coiled tubes, which is made of porous ceramic and are vaporized with a palladium-silver layer on an internal wall. The coil is arranged in an inner chamber of the shift reactor and/or the reformer-reactor. For converting the remaining portions of carbon monoxide, hydrogen and if necessary sulfur oxide and nitrous oxide in the remaining gas of the fuel cell to carbon dioxide, water and innoxious sulfur and nitrogen compounds, a catalyst in a pipe of a heat exchanger (19) is introduced on a porous ceramic carrier in an inner area of the reformer reactor or in an exhaust discharge. An independent claim is included for a device for an exhaust gas-fuel reformer-fuel cells combination.