WO2014117953A1

WO2014117953A1 - Reformer unit for a fuel cell system

Info

Publication number: WO2014117953A1
Application number: PCT/EP2014/000291
Authority: WO
Inventors: Michael Reissig; Juergen Rechberger; Arthur Kliment
Original assignee: Avl List Gmbh
Priority date: 2013-02-04
Filing date: 2014-02-04
Publication date: 2014-08-07
Also published as: AT513931A1; DE112014000673A5; AT513931B1

Abstract

The invention relates to a reformer unit (1), in particular for a fuel cell system (2), having a burner (3) which comprises a combustion chamber (4), and a reformer (5) which is arranged at least in part in the combustion chamber (4), and a first conduit (6) which supplies the reformer (5) with process gas, which comprises in particular recirculated anode off-gas and hydrocarbons. According to the invention, the reformer (5) comprises a manifold (7) into which the first conduit (6) opens out.

Description

Reformer unit for fuel cell system

The invention relates to a reformer unit, in particular for a fuel cell system, with a burner, which has a combustion chamber, a reformer, which at least partially in the

Combustion chamber is arranged and a first line, the

Reformer with process gas, which in particular recirculated

Anode exhaust gas and hydrocarbons has supplied.

Such a reformer unit can, for example, in a

Energy generating unit are used with a fuel cell, which with hydrocarbons and not with pure

Be operated hydrogen. Such fuel cell systems form a compact and efficient energy source, in particular for

Provision of electrical and / or thermal energy.

In particular, in trucks, which - as for example in the US - travel long distances, on which the driver lives in the cab of the trucks, electrical energy during the downtime, z. B. during the breaks of the truck or during the sleep of the truck driver needed. The energy is used to power the truck in the truck (such as a heater),

Multimedia technology (such as radio, TV and

associated receivers) as well as to provide light.

So far, the energy required for this purpose is generated by the so-called "idling." That is, during the life of the truck running its engine, either constantly or at certain intervals, idle to produce the required energy via the alternator State of the art even small

Internal combustion engines that drive a generator and in addition are aboard such a truck, solely for generating energy during the life of the truck, are arranged.

The efficiency of such systems in relation to the generated

Electrical energy is low, since in the conversion process of the diesel engine in the internal combustion naturally a high energy loss caused by generation of heat in the combustion process and by friction in the mechanical movement of the shaft.

The low efficiency is not only energy

wastes, but also large quantities of

Emissions that pollute the environment. Furthermore, running internal combustion engines in standing or powered by external power source vehicles represent a significant source of noise. Finally, the "idling" also causes high costs, since unnecessarily much fuel is consumed and the

Operating hours of trucks may be unnecessarily increased.

From the prior art power generation units are known which generate electrical energy by means of a fuel cell. The efficiency of fuel cells is much cheaper than that of internal combustion engines, as the chemical

Reaction energy of a continuously supplied fuel and an oxidizing agent is converted directly into electrical energy, without energy losses caused by a coupling

Combustion engine / generator or detour via a mechanical movement arise.

However, fuel cells require pure hydrogen,

Methanol, formic acid, methane or the like as a fuel.

Long-chain hydrocarbons, such as diesel or gasoline, that are readily available in a truck can not be directly processed by the common fuel cell types.

In order not to have to carry any separate fuel in the vehicles, are in the art systems with reformers

described with which hydrocarbons initially to from Fuel cell processable process gases reformed and only then be processed by a fuel cell. However, these systems require a lot of energy to reform the hydrocarbons, which in turn reduces the efficiency of the system.

In order to increase the efficiency of such a system for generating energy, DE 10 2007 039 594 A1 therefore discloses on the one hand, the reformer and other elements that are necessary for reforming, and to arrange a fuel cell stack in a compact design in a common external insulation. Furthermore, this document proposes to recycle anode exhaust gas into the reformer in order to utilize the heat energy contained in the exhaust gas and to use the chemical substances contained therein for reforming. The reformer is this purpose in a cylindrical combustion chamber of a

Flame burner arranged to heat the reformer in the starting phase. By applying the reformer wall with hot gas, this is heated and the reformer is a homogeneous

Temperature distribution, which is an efficient reforming

guaranteed.

The present invention has for its object to provide a reformer unit with such a reformer, which is compact, universally applicable and energy-efficient.

This object is achieved by a reformer unit according to claim 1. Advantageous embodiments of the invention are claimed in the dependent claims.

A burner according to the invention is a device for

Execution of a combustion, i. a redox reaction that proceeds with the release of energy in the form of heat and light, ie exothermic.

A combustion chamber in the context of the invention is used for combustion and / or mixing of fuel and oxidant.

A reform in the sense of the patent is any kind of

Reforming or reforming for the production of a synthesis gas, which contains at least hydrogen, in particular

Steam reforming or reforming. A reformer is accordingly an apparatus for reforming.

A manifold according to the invention is a part of the housing of the reformer. The manifold serves, in particular, to conduct a process gas to a reforming catalyst, to mix it and / or to distribute it homogeneously over the surface of a reforming catalyst. Preferably, the manifold is designed as a connection piece and can be referred to as distributor or process gas distributor.

A fuel cell according to the invention is a galvanic cell, which converts the chemical reaction energy of a continuously supplied fuel and an oxidizing agent into electrical energy. In order to obtain a higher voltage, usually several cells are connected in series to a stack (engl., For 'stack').

Upstream within the meaning of the invention, in the flow direction of a fluid, in particular a process gas, above

arranged. Downstream according to the invention accordingly arranged below.

A flow direction in the context of the invention is the

predominant direction of movement of a fluid resulting from the superposition of the various components of motion of the fluid

Molecules of the fluid results.

A longitudinal axis in the sense of the invention is that axis of a

Body corresponding to the direction of its greatest extent and / or its axis of symmetry. A central longitudinal axis is

Accordingly, the longitudinal axis in the center of a body. Purely by way of example, this corresponds to a cylinder of

Symmetry axis.

Deflection means in the sense of the invention are means for interrupting or swirling a fluid flow. An overlap in the sense of the invention is a projection in a defined direction.

A flow volume is the volume which is available to a fluid as it flows through a device.

A process temperature in the sense of the invention is the temperature which in a device when executing a respective

Subprocess is achieved in normal operation.

Isolation in the sense of the invention is any type of

Thermal insulation to reduce the passage of heat energy.

Adiabatic in the sense of the invention means that in the overall process of the power generation unit, both exothermic and endothermic reactions take place in parallel, so that the overall process in the

Substantially independent of external heat input and a large part, in particular more than 25%, preferably more than 30%, most preferably more than 40%, in the supplied

Hydrocarbon-containing energy is converted into electrical energy.

In particular, the reformer unit according to the invention has a

Manifold, in which a first line with process gas for the reformer opens. By the manifold in the reformer of the reformer unit according to the invention a better mixing of the fuel and the carrier gas, which form the process gas, achieved before it is converted by a reforming catalyst in reformate. Furthermore, by the upstream of the manifold a homogeneous distribution of the introduced at an upstream surface of the manifold process gas to a

downstream arranged inflow surface of the reforming catalyst achieved.

In an advantageous embodiment of the reformer unit, the at least one outer surface of the manifold is spaced from the respective opposite surface of the combustion chamber. By the spacing of the outer surface of the manifold of the

Surfaces of the combustion chamber is on the one hand ensures optimum flow around the reformer with combusted in the combustion chamber fuel gas and the exhaust gases. This allows the reformer in one

Starting phase of a fuel cell system quickly on

Operating temperature to be brought. Furthermore, a spacing to the surfaces of the combustion chamber ensures that the reformer or the manifold of the reformer is optimally thermally insulated on all sides.

In a further advantageous embodiment, the

Reformer unit to a starting burner, the exhaust gas is inserted into the burner.

The starting burner provides during the starting phase of the

Fuel cell system for accelerated reaching the

Operating temperatur .

In a further advantageous embodiment of the reformer unit, a flame tube of the starting burner protrudes into the combustion chamber.

By projecting the flame tube into the combustion chamber, the hot exhaust gas of the starting burner can be aimed at the reformer during the starting phase. Anode exhaust gas and / or cathode exhaust air of the fuel cell of a fuel cell system, which during the start-up phase does not yet have the temperatures required to bring about the reforming, however, are forced into the outer regions of the combustion chamber, where they essentially come into contact with the walls of the combustion chamber, but not with the manifold and / or other surfaces of the reformer.

In the combustion chamber, in particular in the outer regions, a thorough mixing of all gases takes place, which at the beginning of the heating phase has the advantage that the hot exhaust gas of the starting burner is first cooled and the material, which is not yet on

Operating temperature is not too high stress. As time goes by, the gases that come from the fuel cell stack heat up and have less and less cooling effect. In a further advantageous embodiment of the reformer unit of the reformer, the burner and / or the starting burner are arranged in such a way that a central longitudinal axis of the reformer, a central longitudinal axis of the burner and / or a central longitudinal axis of the starting burner aligned substantially parallel and in particular identical are.

If the central longitudinal axes of the reformer and the burner are aligned in parallel, this allows a particularly compact arrangement of the two components and thus also a compact

Execution of the reformer unit. If the central longitudinal axes are even coaxial, the isolation of the reformer against the environment will continue to be optimized. Is also the central longitudinal axis of the

Flame tube coaxially aligned, the reformer is optimally flows around during the start phase of the exhaust gases of the starting burner, thereby enabling a speedy achievement of the operating temperature of the reformer.

In a further advantageous embodiment of the reformer unit are between the flame tube and the reformer deflection

arranged.

Such baffles cause turbulence of the exhaust stream from the starting burner, so that the manifold or other walls of the reformer are heated excessively uniformly and not an upstream surface of the reformer.

In a further advantageous embodiment of the reformer unit, the manifold of the reformer at least partially on the shape of a cone or a truncated cone.

The conical or truncated cone shape further leads to a

optimized flow around the reformer with fuel gas or exhaust gas from the starting burner. In addition, the reformer is optimally flown inside with educt gas or reformer process gas.

In a further advantageous embodiment of the reformer unit, an angle between the flow direction of the first Line and a central longitudinal axis of the reformer on a

Entry point into the reformer substantially 45 ° to 135 °, preferably 70 ° to 110 °, more preferably 80 ° to 100 °, and most preferably 90 °.

By adjusting the angle, an optimal turbulence of the process gas in the manifold of the reformer can be achieved.

In a further advantageous embodiment, a tangent to the flow direction of the first line divides at one

Entry into the reformer a stretch between one

central longitudinal axis of the manifold and the at least one

lateral surface, which is arranged substantially perpendicular to the tangent and the central longitudinal axis of the manifold, in

Ratio 4: 1, preferably 3: 1, more preferably 2: 1,

more preferably 1: 1, more preferably 1: 2, even more preferably 1: 3, and most preferably 1: 4, or substantially intersects the central longitudinal axis of the manifold.

Also, by varying the flow direction of the process gas from the first conduit with respect to a direction perpendicular to the central longitudinal axis of the reformer direction optimal mixing and uniform flow of the reforming catalyst can be achieved.

In a further advantageous embodiment, a second line supplies the burner with air, in particular cathode exhaust air, and a third line supplies the burner with fuel gas, in particular substantially anode exhaust gas, wherein the third line opens downstream of the second line in the combustion chamber or the third

Line in the second line, which opens into the combustion chamber, opens.

By arranging the third conduit, which introduces the anode exhaust gas into the burner, downstream of the second conduit, which introduces the cathode exhaust air, both gas streams are ideally mixed. Alternatively, the third line may also be previously in the second line, whereby the fuel of the burner with the Oxidizing agent or the air is already mixed before the gases are introduced into the combustion chamber.

In a further advantageous embodiment, the angle between each of the flow direction of the second conduit and / or the third conduit and a central longitudinal axis of the burner at an entry point into the burner is substantially 45 ° to 135 °, preferably 70 ° to 110 °, more preferably 80 ° to 100 °, and most preferably 90 °.

By varying the flow direction of the process gas from the second and / or third line with respect to a direction perpendicular to the central longitudinal axis of the burner direction optimal mixing and uniform flow of the burner catalyst can be achieved.

In a further advantageous embodiment of the reformer unit, the burner has a burner catalyst which is arranged in a thermally conductive manner around the reformer and / or the reformer has a reforming catalyst.

Due to the thermally conductive arrangement of the burner catalyst on a surface of the reformer optimal transfer of thermal energy from the burner in the reformer, especially during the startup phase is achieved. As a result, on the one hand, the heat transfer between the oxidation catalyst and the

Reformer catalyst and on the other hand, the temperature profiles (axial and radial) are homogenized in the reforming catalyst and / or in the burner catalyst. The improved heat dissipation prevents particularly hot zones (hot spots) in the two catalysts. This is particularly advantageous for heating the reforming catalyst. By additionally directly welding the substrates of the burner catalyst and the reforming catalyst to the outer wall of the reformer, sealing means, such as a sealing mat, can be dispensed with, which additionally hinder the heat exchange. In a further advantageous embodiment of the reformer unit, a substrate of the burner catalyst carries the reformer.

As a result, no further fixing means for the reformer need to be provided.

In a further advantageous embodiment of the reformer unit, the reforming catalyst overlaps with the burner catalyst in the axial direction a quarter, preferably one third, more preferably three quarters and most preferably completely or the overlap of the reformer is variable.

The overlap of the burner catalyst and the

Reformer catalyst controls significantly the thermal conduction between the burner and the reformer.

In a further advantageous embodiment of the reformer unit, the ratio of the flow volume of the

Reforming catalyst to the flow volume of the

Burner catalyst substantially 1: 1, preferably 1: 1.5,

more preferably 1: 2, more preferably 1: 3, and most preferably 1: 3.7.

The burner catalyst is then in relation to the

Reformer catalyst sized large enough, so that in the case of the maximum possible power, in particular a load shedding, no damage to the system caused by overheating.

In a further advantageous embodiment of the reformer unit, the burner is at least partially disposed in an exhaust gas chamber and preferably has a central longitudinal axis, which is coaxial with the central longitudinal axis of the combustion chamber and / or the Manifolds.

The arrangement of the reformer unit in the exhaust chamber allows further isolation from the environment.

The reformer unit preferably comes in one

Power generation unit with a fuel cell, a so-called fuel row system, in particular for a vehicle used.

Such a power generation unit has the advantage that

Hydrocarbons, which are already present in many vehicles in the form of diesel or gasoline, to operate a

Fuel cell can be used.

However, the reformer unit according to the invention is not limited to use in vehicles, but can also be used in purely stationary applications such as cogeneration plants in buildings.

Further advantages, features and applications of the

The present invention will become apparent from the following

Description in connection with the figures.

FIG. 1 is a partially schematic process picture of a

Fuel cell system with an inventive

Reformer unit.

Figure 2 shows a partially schematic cross section of

Fuel cell system with a first embodiment of a reformer unit according to the invention.

FIG. 3 shows a partially schematic, perspective cross-section of the first embodiment of the invention

Reformer unit.

FIG. 4 shows a partially schematic, perspective cross section of a second embodiment of the reformer unit according to the invention.

FIG. 5 shows a partially schematic, perspective cross section of a third embodiment of the reformer unit according to the invention. Figure 6 shows a schematic representation of the geometric

Arrangement of two elements of the reformer unit according to the invention to each other, in particular the first line and the

Reformer manifolds.

FIG. 7 shows a partially schematic cross section through the second embodiment of the reformer unit according to FIG. 4.

The functional principle of the reformer unit 1 according to the invention is explained as follows in an application in a fuel cell system 2 or a power generation unit with a fuel cell on the basis of the process picture according to FIG.

About the fuel port 32 are preferably on the

Hydrocarbon pumps 35a and 35b hydrocarbons, preferably diesel, pumped into the fuel cell system 2. In the starting phase, this pumping process preferably takes place via the

Hydrocarbon pump 35 b, whereby the starting burner 11 with

Hydrocarbon is supplied. Furthermore, with the air blower 29 via the air connection 33, the fuel cell system. 2

preferably supplied with air, which is preferably filtered.

Air and the hydrocarbons are preferably in the

Start burner 11 heated and ignited. This heats the

Start burner 11, the combustion chamber 4 of the preferably arranged around the reformer 5 burner 3 and the reformer. 5

The exhaust gas of the starting burner 11, which flows out of the combustion chamber 4 of the burner 3, is preferably passed through a heat exchanger 28 to the exhaust port 34, which is preferably an exhaust. Air is heated in the heat exchanger 28 and subsequently flows to the cathode K of the fuel cell stack 22a, 22b.

Now, preferably, air is conveyed to the recirculation fan 30 in the reformer 5, where this by the exhaust gas of the

Start burner 11 is heated and then by a preferably present first distributor plate 20 and a preferably existing second distributor plate 27 to the anode A of the

Fuel cell stack 22a, 22b is passed.

Further, the gas flows into the evaporator 26. At this time, hydrocarbons are also pumped via the hydrocarbon pump 35a to the evaporator, which evaporate through the heated anode exhaust gas in the evaporator 26. This gas mixture is preferably mixed with air in the recirculation blower 30 to reformer process gas, the educt gas, and introduced into the reformer 5 via a first line 6 through the combustion chamber 4, in which the process gas is further heated. The reformer 5 is now preferably heated by the starting burner 11 so far that a reforming of the reformer process gas to hydrogen and by-products, the product gas, takes place.

This reformate is in turn passed via the distributor plate 27 to the anode of the fuel cell 2, where now the conversion of substantially hydrogen and oxygen to water and

electrical energy takes place. The electrical energy will

preferably via the electrical connection 36 to a

Consumers derived. During the implementation, heat energy is released.

The heated cathode exhaust air is passed into the combustion chamber 4 of the burner 3. A portion of the heated anode exhaust gas is preferably returned to the evaporator 26. Another part of the

Anode exhaust gas is passed into the combustion chamber 4 of the burner 3.

In the combustion chamber 4, this anode exhaust gas is mixed with the cathode exhaust air and preferably reacted by means of a catalyst in an exothermic reaction. The hereby released

Heat energy is used to heat the reformer 5. The starting burner 11 may preferably now be turned off. The endothermic reaction in the reformer 5 or a preferably present

Reformer catalyst 21 is heated solely by the heat of the exothermic reaction in the fuel cell stack 22a, 22b and the exotherm Reaction in the burner 3 is activated, so that the overall process in the power generation unit is substantially adiabatic.

The reformer unit 1 of the illustrated in the process picture

Fuel cell system 2 preferably has the burner 3 with the combustion chamber 4, the reformer 5 with the Manifold 7, the

Evaporator 26 and / or an exhaust chamber 23 (not shown in Figure 1) on. In the reformer unit 1 are thus in the

Essentially the facilities for conversion of

Hydrocarbons in process gas for the fuel cell 2

drawn together .

Preferably, the starting burner 11 with flame tube 12th

at least partially part of the reformer unit 1.

Optionally, preferably a bypass line (not shown) may be provided from the starting burner 11 directly into the heat exchanger 28. As a result, more thermal power can be provided regardless of the required electrical power. This is

particularly advantageous in those applications in which the fuel cell stack 22a, 22b extremely cold temperatures

is exposed and / or the vehicle much heat for heating or cooling of the interior is required.

Fig. 2 shows the structure of an embodiment of a

Fuel cell system 2 with an inventive

Reformer unit 1 by a plane containing the central longitudinal axis ZF of the flame tube 12 (Strichpunktet), central longitudinal axis ZB of the burner 3 (dotted) and central longitudinal axis ZR of the reformer 5 (dashed).

In the upper part, the fuel cell system 2 has primarily facilities that serve for media supply, for interrupting the media supply or regulation of the media supply and / or for the preparation of the media. Exemplary of this are the

Air blower 29, various valves and / or the

Hydrocarbon pumps 35a, 35b. Preferably is also a

Heat exchanger 28 is present, which heats the intake air, before being supplied to the cathode K of the fuel cell stacks 22a, 22b.

The reformer unit 1 is arranged in the center of the fuel cell system 2. This essentially comprises the means for reforming or converting the hydrocarbons into reformate or process gas for the fuel cell stack 22a, 22b.

According to the embodiment shown in FIG. 2, the reformer is preferably arranged in the combustion chamber 4 of the burner 3. The burner 3 is in turn preferably arranged in an exhaust gas chamber 23, in which the exhaust gas of the burner 3 and / or the exhaust gas of the starting burner 11 is conducted to the heat exchanger 28. The start burner 11 is used in particular to the

To supply the fuel cell system with heat in the starting phase. This is preferably connected via the flame tube 12 to the burner 3, which preferably projects into the combustion chamber 4 of the burner 3 in.

Furthermore, in the exhaust chamber 23, preferably, the evaporator 26 is arranged, which hydrocarbons in the of the

Fuel cell 2 recirculated anode exhaust gas evaporates before it is introduced into the reformer 5. The starting burner 11 and / or the burner 3 serve to heat the reformer 5. The exhaust gas chamber 23 in turn heats the outer wall of the burner 3 or additionally insulates the burner from the environment.

In addition, it may be preferable to provide insulation around the reformer unit 1, which additionally insulates it. The

Exhaust gas chamber 23 simultaneously provides heat energy for vaporization of the hydrocarbons in evaporator 26.

The reformate or process gas for the anode A and the air for the cathode K of the two fuel cell stacks 22a, 22b of this

Embodiment are from the reformer unit 1 on the

Distributor plates 20, 27 passed to the respective terminals.

The cathode exhaust air and the anode exhaust from the

Fuel cell stacks 22a, 22b are preferably via the Distributor plate 20, 27 connected to the respective terminals of the reformer unit. The reformer 5 preferably has a reforming catalyst 21 and the burner 3 has a burner catalytic converter 19.

In the illustrated embodiment, the combustion chamber 4 and the exhaust chamber 23 is bounded by a wall 10b, which is at the same time a fixing plate. Preferably, these extend only to the wall and have another, separate

Boundary wall on. In another embodiment, the walls of the combustion chamber 4 and / or the exhaust chamber 23 may also be arranged at a distance from a fixing plate.

In the lower part of FIG. 2, the fuel cell system (2) of the illustrated embodiment has two fuel cell stacks 22a, 22b. The fixation of these two fuel cell stacks 22a, 22b and / or the distribution of the process gas and the other media or removal of the cathode exhaust air and the anode exhaust gas is preferably carried out via the second distributor plate 27, which is connected to the distributor plate 20 to communicate in a fluid-communicating manner.

Preferably, however, it is also possible to use a fuel cell with a single stack or a fuel cell with more than two stacks.

The fuel cell stacks 22a, 22b are preferably made of SOFC fuel cells, but others may be

Fuel cell types are used, such. Alkaline fuel cells, polymer electrolyte fuel cells, direct methanol fuel cells, formic acid fuel cells,

Phosphoric acid fuel cells, molten carbonate fuel cells, direct carbon fuel cells and / or magnesium air fuel cells or a combination thereof.

The fuel cell system 2 for power generation is preferably surrounded by insulation, which is not shown in FIG. A first embodiment of the reformer unit 1 according to the invention will now be described with reference to FIG. In this

Embodiment, both the reformer 5, the burner 3 and the starting burner 11 with its flame tube 12 have a cylindrical shape. The respective central longitudinal axes ZR, ZB, ZF of the three components lie in this embodiment on each other or are coaxial. This leads to a concentric arrangement of the three components.

Of course, each of the three components may have a shape other than the cylindrical shape and the three components may

preferably also be arranged differently than with identical central longitudinal axes ZR, ZB, ZF.

In the starting phase is via the fuel line 25th

Hydrocarbon introduced into the starting burner 11. There, the hydrocarbons are heated by means of at least one glow plug, mixed with air and then burned. The hot exhaust gas of the starting burner 11 leaves it via the flame tube 12 and heats the combustion chamber 4 of the burner 3.

Due to the concentric arrangement of the starting burner 11 and the reformer 5 is an upstream surface 8 of the

Reformers flows directly from the exhaust gas jet of the starting burner 11 and thereby heated. As shown, the manifold 7 of the reformer 5 on this upstream surface 8 is preferably in the shape of a truncated cone or a cone to the exhaust gas flow from the starting burner 11 to the

Burner catalyst 19 evenly distribute, which the

Reformer 5 preferably surrounds. In the burner catalyst 19 unreacted hydrocarbons can be post-combusted and / or harmful exhaust gas substances are converted. After leaving the burner catalytic converter 19, the exhaust gas flow preferably flows via exhaust gas openings 37 into the exhaust gas chamber 23 (not in FIG. 3)

shown), which preferably surrounds the burner 3.

Preferably, the reformer 5 consists essentially of two

Sections: The manifold 7 with the upstream surface 8 and at least one lateral surface 9 forms a hollow body, in which via the first conduit 6, a process gas is introduced, which is to be reformed. An upstream surface 8 and a lateral surface 9 can in this case also the respective

Designate component of an inclined surface to both directions.

In the illustration shown in Figure 3, this extends

Cavity substantially from the upstream surface 8 to the surface of a preferably present

Reformer catalyst 20 (not shown here). The second

Section of the reformer 5 is essentially of this

Reforming catalyst 20 is formed. In the reforming catalyst 20, the catalytic reforming takes place. On the side facing away from the Manifold 7 leaves the reformed process gas, the

so-called reformate, the reformer 5 preferably on the

distributor plate 27 to the anode A of the fuel cell stack 22a, 22b.

The mixing of the process gas in the manifold 7 and the

Homogeneity of the current flow of the surface of the reforming catalyst 20 depends largely on the geometry of the arrangement of the first conduit 6, which leads the process gas in the reformer 5, and the manifold 7 from.

As shown in Figure 6, this geometry is on the one hand on the solid angle α between a flow direction SR and the

parallel flow direction SR 'of a line 6; 15; 16 and a central longitudinal axis ZR; For example, the respective body 4; 7, in which the respective process gas is introduced defined. By varying this solid angle, the currents or turbulences in the respective body 4; 7 are affected.

Furthermore, this geometry is over a second solid angle in a plane perpendicular to the respective central longitudinal axis ZR; For example, lies, defined. In a cylindrical body 4; 7, as shown in Fig. 6, this solid angle ß at a Entry point 14; 17; 18 are determined. FIG. 7 shows such a solid angle with respect to the flow direction SR2 of the second line 15. It has been found to be particularly advantageous to choose the solid angle β in a range of about 90 ° to 130 °, preferably between 100 ° and 120 ° and on

most preferred in a range around 113.6 °.

For bodies 4; 7 with another geometry is such a determination at the entry point 14; 17; 18 but not appropriate. Therefore, in the context of the present invention, the ratio Sa: Sb is given as a parameter in which the flow direction SR or a tangent to this flow direction SR at the entry point 14; 17; 18 divides a distance S, which on the one hand between the central longitudinal axis ZR; For example, the respective body and a lateral surface of the body and which extends substantially perpendicular to the flow direction SR and / or a tangent to this flow direction SR at the entry point 14; 17; 18 and the central longitudinal axis ZR; For example, it is arranged.

With respect to the angle α1 between the flow direction SRI of the first conduit 6 and the central longitudinal axis ZR of the reformer 5, it has been found that an angular range of 45 ° to 135 ° is advantageous for good mixing and homogenous flow of the reforming catalyst 20 through the process gas. In preferred embodiments, this angle 70 ° to 110 °, still

more preferably 80 ° to 100 °, and most preferably 90 °.

With respect to the ratio of the sections Sla; Slb of the distance Sl between the central longitudinal axis ZR and the at least one lateral surface 9 of the reformer 5, it has been found that a ratio of Sla to Slb 4: 1, preferably 3: 1, more preferably 2: 1, even more preferably 1: 1, even more preferably 1: 2, more preferably 1: 3, and most preferably 1: 4, for a good one

Mixing and homogeneous flow of the reforming catalyst 21 through the process gas is. In the first embodiment shown in Figure 3, the air via the starting burner air supply 24 in Substantially tangential, ie Sla >> Slb, introduced to the surface in the manifold 7.

Another favorable embodiment variant is that the flow direction SRI of the first line 6 intersects the longitudinal axis ZR of the reformer 5 or, in the case of a cylindrical reformer 5 or manifold 7, corresponds to the flow direction SRI of the tangent to the manifold 7 in the direction of rotation, as is pure

by way of example in the embodiment shown in Figure 3 is the case.

Similar to the defined introduction of the process gas from the first conduit 6 into the reformer 5 or the reformer manifold 7, controlled introduction of the process gases into the burner 3 is also advantageous for thorough mixing and uniform distribution of the gas to be converted to the burner catalyst 19.

About different geometries of the second conduit 15, which supplies the burner with air, in particular cathode exhaust air, and via a change in the geometry of the third conduit 16, which supplies the burner with fuel gas, in particular anode exhaust, with respect to the central longitudinal axis ZB of the burner 4, an optimization of the combustion can also be achieved. Again, it has been found that similar angles a.2 and / or a3 and / or

Ratios of the sections S2a, S2b; S3a, S3b of the S2, S3 routes, such as those providing good results with respect to the reformer. As shown in relation to the first embodiment in Figure 3, both air, in particular the cathode exhaust air, as well as the

Anode exhaust gas substantially tangential to the surface of

Combustion chamber 4, i. S2a >> S2b and S3a >> S3b, above the respective ones

Line 15, 16 introduced into the combustion chamber 4.

The substrate of the burner catalyst 19 is preferably made

Metal. Such substrates have a significantly higher

Thermal conductivity over conventional ceramic substrates. Also, the substrate of the reforming catalyst 21 may be made of metal. Preferably, however, this is made of ceramic. For one thing is such a substrate is more favorable than a metal substrate and good thermal conductivity is less important in this reforming catalyst 21. On the other hand, the ceramic substrate has a better sulfur compatibility and can be used at process temperatures of up to 1000 ° C, which can be significant in extreme operating conditions of the reformer unit 1.

The outer shell of the reformer 5 is preferably also made of metal and is preferably connected to the substrate of

Burner catalyst 19 and / or with the substrate of the

Reformed catalyst 21 welded. As a result, the reformer 5 preferably on the one hand in the combustion chamber 4 of the burner. 3

fixed. However, other types of attachment are possible, for example with a press fit or an additional swelling mat. Preferably, the reformer 5 is fixed at other locations.

On the other hand results from the welding a much better heat transfer between the reforming catalyst 21 and the burner catalyst 19. This is particularly advantageous for

Heating up the reforming catalyst.

Another advantage is that improved by the

Thermal conductivity of the temperature profile (axial and radial) of the reformer and burner catalyst can be homogenized.

As a result, particularly hot zones (hot spots) can be prevented in the two catalysts.

In addition, by directly welding the burner substrate or the substrates to the outer wall of the reformer 5, a

Sealing mat between the burner 3 and the reformer 5 accounts, which is more of a hindrance to the heat exchange.

Another possibility for optimizing the reforming process in the reformer 5 is provided by the arrangement of the

Burner catalyst 19 and the reforming catalyst 21 to each other.

By varying the overlap of the two catalysts 19, 21 in the direction of the central longitudinal axes ZR, ZB, the

Heat transfer and thus the reaction rates in the Reformer catalyst 21 and / or the burner catalyst 19 are influenced.

The degree of overlap may be fixed to a quarter, preferably to one third, more preferably to three quarters and most preferably to a complete overlap of the

Reforming catalyst 21 may be set by the burner catalyst. Preferably, however, the degree of overlap is variable and changeable during operation of the fuel cell system to adjust the heat exchange to the respective modes of operation.

Furthermore, the ratio of the flow volume of the reforming catalyst 21 to the flow volume of the

Burner catalyst 19 can be ensured that the

Burner catalyst 21 is designed to burn the reformate in the event of a sudden load shedding without causing irreversible damage to the fuel cell system. The ratio is substantially 1: 1, preferably 1: 1.5, more preferably 1: 2, even more preferably 1: 3, and most preferably 1: 3.7. Purely by way of example, that of the reforming catalyst 21 in the illustrated

Embodiment, a volume of 95,000ccm, the burner catalyst 21 of 358,000ccm on.

With reference to FIG 4, a second embodiment of

The reformer unit according to the invention in a partially schematic, perspective cross-sectional view of the reformer unit 1

shown. The embodiments of the first embodiment and second embodiment are freely combinable, so that further embodiments may arise.

In essence, the operation principle of the reformer unit 1 of the second embodiment is identical to that of the first embodiment

Embodiment. Also in this embodiment, the flame tube 12 of the starting burner 11, the reformer 5 and the Reformermanifold 7 and the combustion chamber 4 of the burner 3 are cylindrical and more preferably concentric with coaxial centric

Longitudinal axes ZR, ZB, ZF arranged. As for this Shown embodiment, the air over the

Start burner air supply 24 substantially tangential to the

Surface of the starting burner in a mixture forming space of the starting burner 11 introduced. Preferably, the air supply but also perpendicular to the surface for e'ine particularly good

Mixing be introduced into the mixture formation space.

A difference from the first embodiment is that the surface 10 b of the combustion chamber is formed or reinforced by a fixing plate used in the fuel cell system 2 for

Fixation of various devices is used. Another difference is that the flame tube 12 of the starting burner 11 projects further into the combustion chamber 4 of the burner 3.

Preferably, however, the flame tube can also be flush on the surface 10b of the combustion chamber 4 with the surface 10b of the combustion chamber 4

be completed and do not protrude into the combustion chamber 4 at all.

Furthermore, the process gas via the first line 6 as long as possible in the burner chamber 4 is performed in order to transfer the heat energy present in the burner 3 also on this gas

or this process gas towards the environment

isolate.

Also in this embodiment, the reforming catalyst 21 is not shown.

Another difference to the first embodiment in this embodiment is that the third line 16, which directs anode exhaust gas into the burner, preferably not directly into the combustion chamber 4 but in the second line 15 opens, which air, preferably cathode exhaust air, into the burner chamber 4 leads. This allows an even better mixing of the

Anodenabgases with the cathode exhaust air for a better combustion in the burner 3. It is also possible conversely that the third line 16 opens into the second line 15 before it then opens into the combustion chamber. The flow direction SR2 of the gas mixture of cathode exhaust air and anode exhaust gas is directed directly to the central longitudinal axis ZB of the burner 3 in this embodiment. At the shown

preferably cylindrical combustion chamber 4 is the

Flow direction SR2 then perpendicular to the surface of the combustion chamber 4. Preferably, however, the gas mixture occurs with a

Flow direction SR2 in the burner 3, which forms an angle in a range around 113.6 ° to a tangent to the surface of the burner 3, as shown in Figure 7.

The embodiment illustrated in FIG. 5 in a partially schematic perspective cross-sectional view is shown in FIG

Essentially identical to the second embodiment of the

Reformer unit. Also the embodiments of this third

Embodiment can be combined with the embodiments of the first and second embodiments in any way.

In essence, this embodiment differs from the second embodiment in that between the flame tube 12 of the burner 11 and the upstream surface 8 of the burner

Manifolds 7 of the burner 5 deflection means 13, are provided.

The deflection means 13 are held in position by a fixing means 31 in the combustion chamber 4 of the burner 3. Preferably, the deflection means 13 is a metal sheet, which is preferably formed as a ball cap, as shown in Figure 5. However, in other embodiments, the deflection means 13 may be formed as any other two- or three-dimensional structure, such as a plate or as a pyramid and / or consist of other refractory materials.

Further preferably, the deflection means 13 recesses, through which a fluid, in particular the exhaust gas of the starting burner 11 can flow. These recesses are preferably, as shown in Figure 5, formed as holes.

The deflection means 13 serve to ensure that the outer walls of the manifold 7, in particular the upstream surface 8 and the at least one lateral surface 9, be heated evenly. The deflection means does not cause overheating in this area and the exhaust gas is distributed homogeneously over the burner catalyst 19.

List of reference numbers:

Reformer unit 1

Fuel cell system 2

Burner 3

Combustion chamber 4

Reformer 5

first line 6

Manifold 7

Located upstream

Surface of the manifold 8

Side surface of the manifold 9

Wall of the combustion chamber 10a, 10b

Starting burner 11

Flame tube 12

Deflection means 13

Entry point 14, 17, 18

Second line 15

Third line 16

Burner catalyst 19

First distributor plate 20

Reforming catalyst 21

Fuel cell stack 22a, 22b

Exhaust gas chambers 23

Starting burner air supply 24

Fuel line 25

Evaporator 26

Second distributor plate 27

Heat exchanger 28

Air blower 29 Recirculation fan 30

Fixing agent 31

Fuel connection 32

Air connection 33

Exhaust port 34

Hydrocarbon pump 35a

Electrical connection 36

Exhaust opening 37

Claims

P a t e n t a n s p r u c h e

Reformer unit (1), especially for one

Fuel cell system

(2), with a burner

(3), which has a combustion chamber (4), and a reformer (5), which is at least partially in the

Combustion chamber (4) is arranged and a first line (6) which supplies the reformer (5) with process gas, which in particular recirculated anode exhaust gas and

Has hydrocarbons, characterized in that the reformer (5) has a manifold (7) into which the first line (6) opens.

Reformer unit (1) according to claim 1, wherein at least one outer surface (8, 9) of the manifold (7) is spaced apart from a respective opposite surface (10a, 10b) of the

Combustion chamber (4) is arranged.

Reformer unit (1) according to claim 1 or 2, wherein the

Reformer unit further has a starting burner (11) which is connected to the combustion chamber

(4), in particular via a flame tube (12), is connected and preferably projects substantially into it.

A reformer unit (1) according to claim 3, further comprising a bypass line for the exhaust gas of the starting burner

Heat exchanger 28 has.

Reformer unit (1) according to claim 3 or 4, wherein the reformer (5), the burner (3) and / or the starting burner (11) are arranged in such a way that a central longitudinal axis (ZR) of the reformer

(5), a central longitudinal axis (ZB) of the burner (4) and/or a central longitudinal axis (ZF) of the starting burner (11) is aligned substantially parallel and in particular coaxial.

6. Reformer unit (1) according to one of the preceding claims, wherein deflection means (13) are arranged between a flame tube (12) and the reformer (5).

7. Reformer unit (1) according to one of the preceding claims, wherein the manifold at least partially has the shape of a cone or a truncated cone.

8. Reformer unit (1) according to one of the preceding claims, wherein the angle (al) between the flow direction (SRI) of the first line (6) and a central longitudinal axis (ZR) of the reformer (5) at an entry point (14) in the Reformer (5) is essentially 45° to 135°, preferably 70° to 110°, more preferably 80° to 100° and most preferably 90°.

9. Reformer unit (1) according to one of the preceding claims, wherein a tangent to the flow direction (SRI) of the first line (6) at an entry point (14) into the reformer (5) forms a distance (Sl) between a central longitudinal axis (ZR ) of the manifold (7) and the at least one lateral surface (9), which is arranged essentially perpendicular to the tangent and the central longitudinal axis (ZR) of the manifold (7), in a ratio (Sla:Slb) 4:1, preferred 3:1, particularly preferably 2:1, more preferably 1:1, even more preferably 1:2, even more preferably 1:3 and most preferably 1:4 divides or substantially intersects the central longitudinal axis (ZR) of the manifold (7).

10. Reformer unit (1) according to one of the preceding claims, wherein a second line (15) supplies the burner (3) with air, in particular cathode exhaust air, and a third line (16) supplies the burner (3) with fuel gas, in particular in

Essentially anode exhaust gas, supplied and the third

Line (16) opens into the combustion chamber (4) downstream of the second line (15) or the third line (16) opens into the second line (15), which opens into the combustion chamber (4).

11. Reformer unit (1) according to one of the preceding claims, wherein the angle (α2, 3) between each

Flow direction (SR2, SR3) of the second line (15) and/or the third line (16) and a central longitudinal axis (ZB) of the burner (3) at an entry point (17,18) into the burner (3) essentially 45 ° to 135°, preferably 70° to 110°, more preferably 80° to 100° and most preferably 90°.

12. Reformer unit (1) according to claim 11, wherein a tangent to the flow direction (SR2, SR3) of the second line (15) and / or the third line (16) at an entry point (17, 18) into the reformer is a distance ( S2, S3) between a central longitudinal axis (ZB) of the burner (3) and the at least one lateral surface (10a, 10b), which is arranged essentially perpendicular to the tangent and the central longitudinal axis (ZB) of the burner (3), in a ratio of 4:1, preferably 3:1, particularly preferably 2:1, more preferably 1:1, still

more preferably 1:2, even more preferably 1:3 and most preferably 1:4 or essentially passes through the central longitudinal axis (ZB) of the burner (3).

13. Reformer unit (1) according to one of the preceding claims, wherein the burner (3) has a burner catalyst (19) which is arranged in a thermally conductive manner around the reformer (5) and / or the reformer (5) has a reformer catalyst (21) having .

14. Reformer unit (1) according to claim 13, wherein a substrate (20) of the burner catalytic converter (19) carries the reformer (5).

15. Reformer unit (1) according to claim 13 or 14, wherein the reformer catalyst (21) with the burner catalyst (19) in the axial direction (ZR; ZB) is a quarter, preferably a third, particularly preferably three quarters and most preferably completely overlapped or where the overlap

is variable.

Reformer unit (1) according to one of claims 13 to 15, wherein the ratio of the flow volume of the

Reformer catalyst (21) to the flow volume of the burner catalyst (19) is essentially 1:1, preferably 1:1.5, more preferably 1:2, even more preferably 1:3 and most preferably 1:3.7.

Reformer unit (1) according to one of the preceding claims, wherein the manifold (7) is at least partially arranged in the combustion chamber (4).