DE202021103801U1 - Gas treatment device - Google Patents

Abstract

Gas treatment device for use with at least two fuel cells, the gas treatment device having a housing with a base plate for mounting the fuel cells on the base plate, the base plate having inlet openings and outlet openings for the passage of cathode gas and anode gas of the fuel cells,
and wherein transition elements in the form of a first and a second half-shell are arranged below the base plate, wherein the first half-shell covers outlet openings for anode and cathode gas for collecting used anode and cathode gas, and wherein the second half-shell covers inlet openings for anode gas for distribution and supply of fresh anode gas to the anode gas inlet openings in the base plate,
and a heat exchanger unit being accommodated in the housing for recovering heat from used anode and cathode gas and for preheating fresh anode gas and fresh cathode gas.

Description

The invention relates to the field of gas treatment devices, in particular to gas treatment devices in conjunction with fuel cells.

Fuel cells, particularly high temperature fuel cells such as solid oxide fuel cells (SOFC), are typically used with gas treatment devices such as heat exchangers. This enables an optimized operation of the fuel cells, as well as an optimized energy balance of the system. However, there is often a problem between the number of components required or desired and the space available. For example, in US 7,771,884 B2 a distribution unit for the anode and cathode gas of two solid oxide fuel cells integrated directly into a connection plate of the fuel cells. However, this document does not refer in detail to a gas treatment device connected to the fuel cells and the pressure losses that occur when such a system is reduced in size.

There is therefore a need to provide a gas treatment device which has a compact design and at the same time enables high energy efficiency. In particular, there is a need to provide a gas treatment device in which a pressure loss due to the downsizing of the device is at least partially compensated for by a special construction of distributor elements.

The invention relates to a gas treatment device for use with at least two fuel cells, which are generally used in the form of fuel cell stacks. The device is preferably designed for use with two fuel cell stacks, but can very easily be expanded for use with three, four or more fuel cell stacks, as described further below.

The gas treatment device has a housing with a base plate for mounting the fuel cells on the base plate. The base plate has inlet openings and outlet openings for the passage of cathode gas and anode gas of the fuel cells. Transition elements in the form of a first and a second half-shell are arranged below the base plate. The first half-shell covers, preferably all, outlet openings for anode and cathode gas for collecting used anode and cathode gas. The second half-shell covers, preferably all, inlet openings for anode gas for distributing and supplying fresh anode gas to the inlet openings for anode gas in the base plate. A heat exchanger unit is accommodated in the housing for recovering heat from used anode and cathode gas and for preheating fresh anode gas and fresh cathode gas.

The two half-shells enable gas to flow as freely as possible from and to the feedthroughs in the base plate and thus to the fuel cells and to gas treatment components, such as the heat exchanger unit, but also reformers or catalytic burners, which are preferably used in the device. The width of the half-shells enables a transition with little pressure loss and an improvement in the evenness of gas flows compared to pipes or elbows. In addition, half-shells have a very flat structure, so that a parallel arrangement of the half-shells to the base plate forms space-saving transition elements, so-called interfaces or distributors. The fuel cells can be connected directly to the heat exchanger unit via the transition elements. However, there are preferably further gas treatment components which, when the gas treatment device is in use, are interposed between the fuel cell and the heat exchanger unit and are also accommodated in the housing. Such further gas treatment components are, for example, reformers and catalytic burners, as mentioned above.

The housing preferably has two catalytic burners, which are preferably arranged parallel to one another. The catalytic burners are connected at their respective inlet ends to outlet openings in the first half-shell and at their respective outlet ends are connected to the heat exchanger unit via a common collecting element. The first half-shell preferably has two outlet openings, which outlet openings are arranged at a distance from one another in lateral regions of the first half-shell.

The common collecting element is preferably a half-shell construction. Two half-shells are attached to each other. The common collecting element is preferably arranged in such a way that one half-shell essentially forms a closing transverse side in the housing, while the opposite half-shell has the connection openings for the catalytic burners. The collecting element is preferably connected directly to the heat exchanger unit with a wide outlet opening.

The housing preferably has a reformer. The reformer is connected at its inlet end to the heat exchanger unit and at its outlet end to the second half-shell. A fuel is used in the reformer, preferably Natural gas, converted into hydrogen, which hydrogen is then converted into electricity and heat in downstream fuel cells.

The fuel is preheated in the heat exchanger unit for optimal efficiency for reforming the fuel in the reformer.

The gas treatment device preferably has a heat exchanger unit with two heat exchangers arranged in series. The first of the two heat exchangers is provided for heating reformer gas, that is to say fuel that can be converted into hydrogen in the reformer. The downstream second heat exchanger is provided for heating fresh cathode gas.

With the provision of two heat exchangers, one heat exchanger can be optimized for its function: a first heat exchanger arranged upstream for heating smaller amounts of reformer gas, which are, however, preferably strongly heated, and a second heat exchanger arranged downstream for preheating larger amounts of cathode gas , typically ambient air.

The first heat exchanger can be dimensioned correspondingly smaller, since smaller amounts of gas are treated therein. The second heat exchanger is preferably dimensioned larger in order to be able to preheat larger quantities of fresh cathode gas.

The second heat exchanger preferably has a collecting element for heated cathode gas. At one end, the collecting element preferably extends essentially over an entire width of the second heat exchanger. At its second end, the collecting element is connected to inlet openings for cathode gas in the base plate via separate line sections.

Since anode gas is used in smaller quantities, a plurality of small inlet and outlet openings for anode gas, for example two per fuel cell, are preferably provided in the base plate. Since cathode gas, that is to say oxidation gas, is used in larger quantities, one large inlet opening and one large outlet opening are preferably provided for each fuel cell. In a preferred embodiment, the base plate thus has four large through openings for cathode gas and eight smaller through openings for anode gas. The base plate can have further through openings for further elements. For example, the base plate has a passage opening for exhaust gas.

A collecting element which is connected to a heat exchanger preferably has two half-shells attached to one another. The same advantages apply to the collecting element as to individual half-shells: a transition to or from the heat exchanger and other components of the gas treatment device with little pressure loss and an improvement in the evenness of the flow compared to pipes or elbows. In addition, the collecting element allows the functional division of the two heat exchangers, regardless of how many fuel cells are used together with the gas treatment device. The respective half-shells of the transition element or the collecting elements can be provided with the respective number of outlet openings, for example with more than two catalytic burners, or with more than two inlet openings, for example in the collecting element between the burner and the heat exchanger.

Since preferably only one of the two half-shells of a collecting element is provided with the separate inlet or outlet openings, only one half-shell of a collecting element has to be adapted to the use of the gas treatment device with more than two fuel cells, or more so two catalytic burners.

The catalytic burners are preferably arranged parallel to one another and preferably parallel to and above the heat exchanger unit. The catalytic burners are preferably arranged below the first and second half-shells. The collecting elements preferably run perpendicular to the burners and the heat exchanger unit. A very compact device can be produced with the collecting elements made from half-shells between the components of the gas treatment device. The compactness of the device is relevant not only with regard to the space available or not, but also with regard to costs and energy efficiency.

A smaller housing has a smaller surface via which heat is radiated into the environment, which heat is thus lost for the system and energy generation. In addition, cavities in a housing are usually filled with thermally insulating material. Smaller and fewer cavities require correspondingly smaller amounts of thermally insulating material, so that material costs can be saved.

Preferably, cavities in the housing of the gas treatment device are filled with thermally insulating material. The thermally insulating material can be any suitable thermally insulating material, preferably a microporous one thermally insulating material. A thermally insulating material is preferably a thermally insulating powder, for example a microporous powder with low thermal conductivity. This enables the insulation material to be well distributed even in small spaces and areas in the housing that are difficult to access. A thermally insulating material preferably has a specific thermal conductivity of less than 0.07 W / K * m.

The thermal insulating material, as well as the materials of components and transition elements used in the gas treatment device, are preferably resistant to high temperatures. They preferably have a temperature resistance of at least 750 degrees Celsius or 950 degrees Celsius.

When the gas treatment device is in use and in certain embodiments, at least two fuel cells, in particular high-temperature fuel cells, are attached to the base plate. A high temperature fuel cell is preferably a solid oxide fuel cell (SOFC).

Preferably the two or more fuel cells are identical fuel cells. Fuel cells or fuel cell stacks are preferably arranged symmetrically on the base plate.

Preferably the two or more catalytic burners are identical catalytic burners. Catalytic burners are preferably arranged symmetrically in the housing.

The gas treatment device preferably has the same number of catalytic burners as fuel cells are or can be attached to the base plate. The catalytic burners are preferably all arranged parallel to one another, and preferably directly next to one another or one above the other in the housing.

In preferred embodiments of the gas treatment device, used anode and cathode gas from all fuel cells used with the device is treated in a first heat exchanger and reformer gas is heated for all fuel cells. In a second heat exchanger, cathode gas is heated for all fuel cells used with the device. This allows a functional separation for the heat exchangers regardless of the number of fuel cells with which the gas treatment device is used. It is also possible to expand the gas treatment device for use with more than two fuel cells, essentially without changing the heat exchanger unit.

Half-shells used in the device or elements made from half-shells enable a very uniform and, as far as possible, unobstructed flow of gas. In addition, diameters and curvatures in pipes or transitions are preferably used in the device and its components, which diameters are preferably large and which curvatures preferably have no angles of curvature smaller than 90 degrees.

• 1 eine Ansicht auf eine Gasbehandlungsvorrichtung;
• 2 eine Ansicht auf ein bevorzugtes Innenleben einer Gasbehandlungsvorrichtung gemäss 1;
• 3 katalytische Brenner und Wärmetauscher der Vorrichtung aus 2;
• 4 die Vorwärmeinheit von Kathodengas gemäss 2;
• 5 eine Variante der Gasbehandlungsvorrichtung mit Zusatzeinheit als Umwälz-Wärmetauscher.

In the following, the invention is explained in more detail on the basis of examples of figures. It shows:

• 1 a view of a gas treatment device;
• 2 a view of a preferred inner workings of a gas treatment device according to 1 ;
• 3 catalytic burners and heat exchangers of the device 2 ;
• 4th the preheating unit of cathode gas according to 2 ;
• 5 a variant of the gas treatment device with an additional unit as a circulating heat exchanger.

In the figures, the same reference symbols are used for the same elements.

1 shows an external view of the gas treatment device 1 , which in a cuboid housing 10 is housed. The case 10 , preferably made of metal or high-temperature-resistant material, has an upper base plate 11th , four side walls 12th and a base plate 13th on. Two high temperature fuel cells, preferably SOFS, can be placed on the base plate 11th attached (not shown).

The base plate 11th has several through openings. In particular, it has four cathode openings 20, 21 and eight smaller anode openings 22, 23. The through openings are regular in the base plate 11th arranged distributed.

The one on the base plate 11th Cathode and anode openings 21, 23 drawn on the right in the figure are for the passage of cathode gas and anode gas into the two on the base plate 11th attached fuel cells or their cathodes and anodes. Examples of inside diameters of anode openings are 8mm to 15mm. Examples of inner diameters for cathode openings are 15mm to 35mm.

The one on the base plate 11th Cathode and anode openings 20, 22 drawn on the left in the figure are for carrying out used Cathode gas and anode gas from the two on the base plate 11th attached fuel cells or their cathodes and anodes to the components of the gas treatment device.

The base plate 11th has an exhaust port 25th for introducing an exhaust pipe 6th on. There is also an additional unit 7th on the base plate 11th appropriate. The additional unit can be, for example, an additional heating module for heating up the heat exchangers 41, 42 during a cold start. However, it can also be a circulating heat exchanger, as in 5 is described in more detail.

A side opening 29 in a side wall 12th is for supplying cooling gas to the catalytic burners 40 intended.

In 2 is the inner workings of the gas treatment device without a housing 10 shown. The two half-shells 50, 51 are close to the bottom of the base plate 11th appropriate. The first half-shell 50 covers the cathode and anode outlet openings 20, 22. The second half-shell 51 covers the anode inlet openings 23 .

Two on the side of the first half-shell 50 introduced openings 501 are via two short pieces of pipe 54 to one catalytic burner each 40 connected. The two catalytic burners 40 are arranged parallel to each other. They have a common, centrally located cooling inlet 400 on. This is used to supply preferably cold air, such as ambient air, to the burner if required 40 to cool and avoid damage due to thermal overheating.

A downstream end of the catalytic burners 40 each opens into a collecting element 60 , as in 3 is easy to see. The collecting element 60 consists of two half-shells and collects one in the catalytic burners 40 oxidized, reacted and, due to the exothermic reactions in the burners, further heated exhaust gas and leads this to a first heat exchange 41 . The collecting element 60 has for this purpose a single large outlet opening which connects to an inlet opening 411 in the first heat exchanger 41 connected. The inlet opening 411 extends essentially over the entire width of the first heat exchanger 41 what in 4th is easy to see.

In the first heat exchanger 41 the heated exhaust gas is used to preheat fuel. The preheated fuel enters the reformer attached to the first heat exchanger 43 . In it, fuel, preferably natural gas, is converted into hydrogen. Hydrogen is required to produce energy in the fuel cells. The one in the reformer 43 The reactions taking place are endothermic, so that the reduced gas cools down in the reformer.

The reformer 43 , a substantially tubular component, is attached to a central reformer port 510 in the second half-shell 51 connected. In the half-shell 51 the hydrogen gas mixture required for the fuel cells is adjusted to the width of the base plate 11th and evenly on the anode inlet openings 23 distributed.

As in 3 clearly visible is the first heat exchanger 41 over a connection 410 with a second heat exchanger 42 connected. After the exhaust gas in the first heat exchanger 41 Has given off heat to the fuel, the cooled but still warm exhaust gas is passed through the connection 410 into the second heat exchanger 42 guided. In the second heat exchanger 42 , which is made slightly larger than the first heat exchanger 41 , the residual heat in the exhaust gas is used to preheat cathode gas, an oxidizing gas, typically ambient air.

The heated cathode gas is via another collecting element 61 , which in turn is made of two half-shells, at the outlet 420 the second heat exchanger collected. Due to the narrow and wide design of the collecting element 61 , heated cathode gas can flow from bottom to top between the burners with practically no obstacles 40 be passed through and through the device. The collecting element 61 has at its upper end of one half-shell two connection openings and connection pipes attached to them 52 on. The ends 520 of the connecting pipes running parallel to each other 52 are with the cathode inlet ports 21 in the base plate 11th connected.

The exhaust gas in the first heat exchanger 41 for preheating fuel gas and in the second heat exchanger 42 Was used to preheat the oxidizing gas is now connected to an outlet opening 421 in the second heat exchanger 42 attached exhaust pipe 6th , released to the environment.

5 shows the gas treatment device with an additional unit 7th in the form of a circulating heat exchanger. Part of the anode gas flow is from the half-shell 50 branched off before the anode gas flow into the catalytic burner 40 is initiated. The branched off anode gas stream flows through the circulation heat exchanger and is connected by means of a connecting pipe 71 passed into the first heat exchanger 41. The additional unit 7th thus acts as a cooler for the branched anode gas flow.

The device shown and described is very symmetrical, especially what the arrangement and configuration of the individual components of the device is concerned. This is particularly advantageous in the manufacture of the components, but also in relation to the most homogeneous and uniform gas flow possible in and through the device and its components.

In the embodiment of the device shown in the figures, the device is designed for use with two fuel cells or fuel cell stacks, in particular high-temperature fuel cells, arranged next to one another and operated in parallel. However, the device can easily be adapted for use with more than two fuel cells. This can be done in that essentially only the base plate (enlarge, larger number of through openings) and the half-shells (enlarge) or cathode / anode connections are adapted. Preferably, however, a separate catalytic burner is also assigned to each fuel cell, so that a collecting element is also provided with a higher number of connections for the higher number of burners. However, in an unchanged arrangement, the heat exchanger unit can also be used for a larger number of fuel cells.

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• US 7771884 B2 [0002]

Claims (12)

Gas treatment device for use with at least two fuel cells, the gas treatment device having a housing with a base plate for mounting the fuel cells on the base plate, the base plate having inlet openings and outlet openings for the passage of cathode gas and anode gas of the fuel cells, and wherein transition elements in the form of a first and a second half-shell are arranged below the base plate, wherein the first half-shell covers outlet openings for anode and cathode gas for collecting used anode and cathode gas, and wherein the second half-shell covers inlet openings for anode gas for distribution and supply of fresh anode gas to the anode gas inlet openings in the base plate, and a heat exchanger unit being accommodated in the housing for recovering heat from used anode and cathode gas and for preheating fresh anode gas and fresh cathode gas. Gas treatment device according to Claim 1 wherein the housing has two catalytic burners which are connected at their respective inlet ends to outlet openings in the first half-shell and at their respective outlet ends are connected to the heat exchanger unit via a common collecting element. Gas treatment device according to one of the preceding claims, wherein the housing has a reformer which is connected at its inlet end to the heat exchanger unit and at its outlet end to the second half-shell. Gas treatment device according to one of the preceding claims, wherein the heat exchanger unit has two heat exchangers arranged in series, wherein the first of the two heat exchangers is provided for heating reformer gas, and wherein the downstream second heat exchanger is provided for heating fresh cathode gas. Gas treatment device according to Claim 4 , wherein the second heat exchanger has a collecting element for heated cathode gas, which collecting element extends at one end essentially over the entire width of the second heat exchanger and at its second end is connected to inlet openings for cathode gas in the base plate via separate line sections. Gas treatment device according to Claim 2 or 5 , wherein a collecting unit has two half-shells attached to one another, only one of the two half-shells having at least two separate inlet or outlet openings. Gas treatment device according to one of the preceding claims, if applicable, wherein the catalytic burners are arranged parallel to and above the heat exchanger unit, and wherein the catalytic burners are arranged below the first and second half-shells. Gas treatment device according to one of the preceding claims, wherein cavities in the housing are filled with thermally insulating material. Gas treatment device according to Claim 8 wherein the thermally insulating material is a microporous powder with low thermal conductivity. Gas treatment device according to one of the preceding claims, wherein at least two fuel cells, in particular two high-temperature fuel cells, are attached to the base plate. Gas treatment device according to Claim 10 An equal number of catalytic burners are arranged parallel to one another in the housing as fuel cells are mounted on the base plate. Gas treatment device according to one of the Claims 10 until 11th , wherein a first heat exchanger treats spent anode and cathode gas for all fuel cells and heats reformer gas for all fuel cells, and a second heat exchanger heats cathode gas for all fuel cells.

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