Evaporator and fuel cell arrangement

Abstract

The invention relates to an evaporator (V) comprising an evaporator body (3) surrounded by an evaporator housing (5) having an inlet (1) for supply of liquid into the evaporator housing (5) and an outlet (6) for discharge of vapour generated, wherein the evaporator body (3) comprises a multitude of plates (7) arranged flat one on top of another, wherein there is a liquid distributor (2) for distributing the liquid between the multitude of plates (7) arranged between the inlet (1) and the evaporator body (3), wherein each of the plates (7) comprises, on a first surface, a liquid distributor structure (10) with distributor conduits (20, 21, 22), an evaporator area (11) and a gas collection structure (12). The invention further relates to a corresponding fuel cell arrangement.

Claims

1. An evaporator comprising an evaporator body surrounded by an evaporator housing having an inlet for supply of liquid into the evaporator housing and an outlet for discharge of vapour generated, wherein the evaporator body is structurally separate from the evaporator housing, wherein the evaporator body comprises a multitude of solid closed plates arranged flat, one solid closed plate on top of another solid closed plate, wherein there is a liquid distributor for distributing the liquid between the multitude of solid closed plates, wherein the liquid distributor is arranged between the inlet and the evaporator body, wherein each of the solid closed plates comprises, on a first surface, a liquid distributor structure with distributor conduits, an evaporator area and a gas collection structure, wherein the liquid distributor structure comprises a distributor feed which branches into at least two first distributor conduits; and wherein at least some of the solid closed plates have heating channels on a face opposite the first surface of the solid closed plate, said heating channels having fluid connection via a further inlet and a further outlet provided in the evaporator housing.

2. The evaporator according to claim 1, wherein the liquid distributor structure is in one-piece form together with the solid closed plate of the multitude of plates.

3. The evaporator according to claim 1, wherein the liquid distributor structure opens into the evaporator area.

4. The evaporator according to claim 1, wherein the evaporator area takes the form of a depression or elevation in the solid closed plate.

5. The evaporator according to claim 1, wherein the evaporator area comprises a structured region with a raised and/or depressed pattern.

6. The evaporator according to claim 5, wherein the pattern is a herringbone pattern.

7. The evaporator according to claim 1, wherein the evaporator area comprises grooves which have deflection sites or channels which have deflection sites and run in a direction pointing away from the liquid distributor structure.

8. The evaporator according to claim 7, wherein the channels run in the form of a wave.

9. The evaporator according to claim 1, wherein the gas collection structure comprises at least two gas collection conduits which are combined, and/or a curved outlet channel.

10. The evaporator according to claim 1, wherein at least some of the solid closed plates are flat on a second face opposite the first surface.

11. The evaporator according to claim 1, wherein two adjacent solid closed plates are stacked flush one on top of another.

12. The evaporator according to claim 11, wherein edges of the liquid distributor structure, the evaporator area and the gas collection structure form a seal with a solid closed plate arranged adjacent thereto.

13. A fuel cell arrangement comprising at least one evaporator according to claim 1, a reformer (R), a PrOx reactor (P) and a fuel cell (B).

14. A method of producing power in a fuel cell comprising processing a propylene glycol/water mixture through the fuel cell arrangement of claim 13.

Description

(1) The invention is elucidated hereinafter with reference to drawings. The drawings show:

(2) FIG. 1 a schematic drawing of an evaporator of the invention in cross section,

(3) FIG. 2 a first configuration of an evaporator plate of an evaporator of the invention,

(4) FIG. 3 a cross section through the evaporator plate according to FIG. 2 along the line III-III′,

(5) FIG. 4 a cross section through the evaporator plate according to FIG. 2 along the line IV-IV′,

(6) FIG. 5 a cross section through the evaporator plate according to FIG. 2 along the line V-V,

(7) FIG. 6 a second configuration of an evaporator plate,

(8) FIG. 7 a detail enlargement of the evaporator plate according to FIG. 6,

(9) FIG. 8 a cross section through the evaporator plate according to FIG. 7, and

(10) FIG. 9 a fuel cell arrangement according to the invention.

(11) FIG. 1 shows an evaporator V having an inlet 1, an evaporator housing 5 and an outlet 6. A liquid distributor 2 is connected between the inlet 1 and an evaporator body 3, with which a liquid is distributed between plates 7. The liquid distributor 2 in this working example takes the form of a cavity 8. However, the liquid distributor 2, in an alternative configuration, may also comprise a treelike liquid distributor structure. The plates 7 are arranged flat one on top of another, such that the stack of the plates 7 is apparent in FIG. 1.

(12) FIG. 2 shows a configuration of a plate 7. The plate 7 comprises a liquid distributor structure 10. The liquid distributor structure 10 has a distributor feed 20 which divides into first distributor conduits 21, especially two first distributor conduits 21. The first distributor conduit 21 may further divide into second distributor conduits 22 and subsequently into third distributor conduits 23. The first 21, second 22 and third distributor conduits 23 form a treelike structure, such that the cross section, for example, of a first distributor conduit 21 is equal to the sum total of the second distributor conduits 22 that branch off therefrom. Such a liquid distributor structure 10 results in application of the liquid to an evaporator area 11 at a uniform pressure and a uniform rate.

(13) The evaporator area 11 is an essentially rectangular area. In a middle region, a pattern 13 is formed on the evaporator area 11 in a direction from the liquid distributor structure 10 to the gas collection structure 12. The evaporator area 11 takes the form of a depression in the plate 7. The pattern 13 is a raised structure, for example a herringbone pattern. The herringbone pattern prevents the liquid from flowing to the gas collection structure 12 without deflection by the liquid distributor structure 10. The pattern 13 forms an open structure, such that blockage of individual channels on the evaporator area 11 is efficiently prevented.

(14) The gas collection structure 12 includes two gas collection conduits 30. There are further structural elements present in the gas collection conduits 30 that take the form of stubs 32. The gas collection conduits 30 collect the gas and open into an outlet channel 31. The outlet channel 31 appropriately has a deflection, such that the gas generated, the vapour, is discharged on one side of the plate 7.

(15) FIG. 3 shows a cross section of the plate 7 according to FIG. 2 along the section line III-III′. The cross-sectional view cuts through four second distributor conduits 22. The second distributor conduits 22 each have the same depth and each have the same width.

(16) FIG. 4 shows a cross section of the plate 7 according to FIG. 2 along the section line IV-IV′. This clearly shows the recessed evaporator area 11 with the pattern 13 protruding above it. The grooves generated by the pattern 13 all have the same depth. The elevations of the pattern 13 are thus at the same level as the unstructured edge of the plate 7. It is thus possible for two plates 7 lying one on top of another to be sealed, especially towards the edge, and simultaneously to be supported on one another by virtue of the elevations in the pattern 13.

(17) FIG. 5 shows a cross section through the gas collection structure 12. The stub 32 arranged in the gas collection conduit 30 and an edge of the plate 7 have the same height.

(18) FIG. 6 shows a further configuration of a plate 7. In a departure from the first execution according to FIG. 2, the plate 7 has a pattern 13 in the form of wavy channels 14. One dimension of the channels 14 is in the region of width about 1 mm with a smaller depth. The wavy channels 14 extend solely within a middle region of the evaporator area 11.

(19) A section of such channels 14 is shown in top view in FIG. 7 and in cross section in FIG. 8. The channels 14 have the same depth.

(20) FIG. 9 shows a fuel cell arrangement. The fuel cell arrangement is a series connection of an evaporator V, followed by a reformer R, a water-gas shift reactor W, a PrOx reactor P and a fuel cell B. The evaporator V is an evaporator according to the preceding working examples. By virtue of the series connection of the reactors, the fuel evaporated in the evaporator V, especially a propylene glycol/water mixture, is processed such that it can be used for generation of power in the fuel cell B. The fuel cell B in this working example has a power of 5 kW.

LIST OF REFERENCE NUMERALS

(21) 1 inlet 2 liquid distributor 3 evaporator body 5 evaporator housing 6 outlet 7 plate 8 cavity 10 liquid distributor structure 11 evaporator area 12 gas collection structure 13 pattern 14 channel 20 distributor feed 21 first distributor conduit 22 second distributor conduit 23 third distributor conduit 30 gas collection conduit 31 outlet channel 32 stub B fuel cell P PrOx reactor R reformer V evaporator W water-gas shift reactor