KR100723142B1 - A micro reformer having catalyst filters in microchannels - Google Patents

Abstract

A reformer having a catalytic filter in a microchannel is provided to achieve miniaturization of a fuel cell.

The present invention, the substrate of a certain size; A channel formed on the substrate; A catalyst filter formed at an inlet side and an outlet side of the channel; A particulate catalyst packed in the channel; And a cover for covering the channel; to provide a reformer having a catalyst filter in a microchannel through which fuel gas passes through the catalyst in the channel to reform.

According to the present invention, a catalyst filter is formed on the inlet side and the outlet side of the reforming subchannel, and the catalyst can be uniformly filled in the microchannel of the reforming portion, thereby increasing the reaction table area of the fuel gas and the catalyst, thereby improving the efficiency of the reforming. The effect can be obtained. In addition, it has a compact structure and can achieve a high efficiency reforming effect using the filling catalysts, thereby achieving the effect of miniaturizing the fuel cell and increasing the power output density.

Fuel Cells, Micro Channels, Catalytic Filters, Reformers, Particle Catalysts

Description

A reformer having a catalyst filter in microchannels {A Micro Reformer Having Catalyst Filters in Microchannels}

1 is a cross-sectional view showing a thin reformer according to the prior art.

A) to h) of FIG. 2 is a process flow diagram showing a step-by-step process for producing a thin reformer according to the prior art.

3 is a cross-sectional view showing a catalyst coated thin reformer according to the prior art.

4 is an exploded perspective view showing a reformer having a catalytic filter in a microchannel according to the present invention.

5 is a cross-sectional view of a reformer having a catalytic filter in a microchannel according to the present invention.

6 is a plan view showing the structure of a catalyst filter in a reformer having a catalyst filter in a microchannel according to the present invention.

         a) a plan view with one row of projections

         b) a plan view with two rows of projections;

Figure 7 a) to d) is a process flow chart showing a state in which the catalyst is filled in the reformer having a catalyst filter in the microchannel according to the present invention.

8 is a photograph showing a catalyst filter provided in the reformer according to the present invention.

        a) a photograph before the catalyst charge,

        b) is a photograph after catalyst filling.

       <Description of the symbols for the main parts of the drawings>

1 ..... Reformer according to a preferred embodiment of the present invention

10 .... Substrate 20 .... Fuel Inlet

30 .... evaporation part 32 .... defoaming means

36,48 .... heating means 40 .... reforming part

42 .... Euro 44 .... Bulkhead

46 .... particulate catalyst 50 .... catalytic filter

52 .... turning 54 .... gap

60 .... Hydrogen exhaust section 100 .... Cover

110 ... fuel inlet 120 .... hydrogen outlet

130 ... Catalyst inlet 140 .... Syringe for catalyst injection

350 .... conventional reformer 352 .... evaporation chamber

354 .... Joint 356 .... Heater

358 .... Fuel injection means 360 .... Mixture of alcohol and water

362 .... Micro Channel 364. ... Reforming Catalyst

400 .... Silicon Wafer 402 .... Thin Film Heater

404 ... electrode layer 406 ... insulating film

410 .... Euro 412 .... Catalyst layer

The present invention relates to a reformer used in a fuel cell, and more particularly, to efficiently and uniformly fill a fuel reforming catalyst therein to improve reforming effect, and to increase the reaction surface area of fuel gas and catalyst, thereby improving high efficiency. The present invention relates to a reformer having a catalytic filter in a microchannel improved to achieve an effect and to be compact, thereby miniaturizing a fuel cell.

Recently, the use of portable small electronic devices such as mobile phones, PDAs, digital cameras, notebook PCs, etc. is increasing. In particular, as DMB broadcasting for mobile phones is started, the performance of power supply is required in portable small terminals. Lithium ion secondary batteries, which are currently used in general, have a capacity to watch DMB broadcasts for 2 hours, and although performance is being improved, expectations for a small fuel cell are increasing as a fundamental solution.

The small fuel cell can be implemented by direct methanol, which directly supplies methanol to the fuel electrode, and reformed hydrogen fuel cell (RHFC), which extracts hydrogen from methanol and injects the fuel into the fuel electrode. As the PEM (Polymer Electrode Membrane) method, hydrogen is used as fuel. Therefore, it has advantages in high output, power capacity that can be realized per unit volume, and no reactants other than water, but it also has disadvantages in miniaturization because a reformer must be added to the system.

As such, in order to obtain a high power output density of the fuel cell, a reformer for making the fuel gas into a gaseous fuel such as hydrogen gas is essential. Such a reformer includes an evaporation unit for vaporizing an aqueous methanol solution, and a reforming unit for converting methanol, which is a fuel, into hydrogen through a catalytic reaction at a temperature of 250 ° C. to 290 ° C.

This reformer is an endothermic reaction proceeds in the reforming unit, the reaction efficiency is good to maintain the temperature of the portion between 250 ℃ to 290 ℃.

A conventional reformer is the reformer 350 of Japanese Patent Laid-Open No. 2003-048701 as shown in FIG. As shown in FIG. 1, the conventional small reformer 350 is provided with a cavity 354 in the evaporation chamber 352 and a heater 356 for evaporation in the cavity 354. The cavity 354 is provided with a fuel injection means 358, which injects a mixture 360 of methyl alcohol and water as fuel into the cavity 354. The fuel mixture liquid 360 injected as described above is heated and evaporated by the evaporation heater 356.

As described above, the gas obtained by vaporizing the mixed solution 360 flows into the microchannel 362 and is reformed into hydrogen and carbon dioxide by the reforming catalyst 364 coated in the microchannel 362.

2 shows a process for coating the reforming catalyst in the microchannel of such a reformer.

Such a process has a dip-coating method, which is representative of the method, in order to first form a thin film heater 402 and an electrode layer 404, as shown in Figure 2a). Ta-Si-ON is formed for the heater, and these layers are formed on the silicon wafer 400 by sputtering Au for the electrode.

As shown in FIG. 2B), patterns are formed in the thin film heater 402 and the electrode layer 404 by photolithography. An insulating film 406 is then formed as shown in Fig. 2C, and a photoresist is formed on the opposite side of the silicon wafer 400 by photolithography.

Also, as shown in FIG. 2D), a flow path 410 is formed on the back surface of the silicon wafer 400 through sandblasting, and these silicon wafers 400 are shown in FIG. 2E. Cut into pieces.

Next, a Cu / ZnO / Al ₂ O ₃ catalyst layer 412 is coated on the flow path 410 as shown in FIG. 2F). In this process, a dry-film photoresist 414 is placed on a portion other than the flow path 410 for selective catalyst coating in the flow path 410. In addition, an Al ₂ O ₃ boehmite layer is formed on the flow path using a dip coating method. This is to increase the adhesion between the catalyst and the flow path wall.

Next, the Al ₂ O ₃ Boehmite layer is dried at 100 ° C., and then Cu / ZnO / Al ₂ O ₃ catalyst layer 412 is secondly formed as shown in FIG. 2G by dip coating. After the coating is completed as described above, it is completed as shown in Fig. 2h by anodic bonding with the pyrex glass substrate 420.

3 shows the reformer thus completed.

However, such conventional reformers have an inefficient problem in the process of reforming fuel gas. The reason for this is that the reforming action is performed while the fuel gas passes through the reforming passages 362 and 410. However, in the conventional reformer as described above, the catalyst layer 364 and 412 having a limited fuel gas area. This is because the reaction rate of the fuel gas is lowered, thereby lowering the conversion rate of the fuel gas into hydrogen.

As a solution to solve such a problem, a method of filling the catalyst in the flow path of the reforming unit may be proposed. In this way, when the catalyst is filled in the flow path of the reforming unit, the reaction surface area is increased, and the hydrogen conversion rate of methanol is greatly increased. In addition, it has been reported that the drive temperature of the reforming unit can be significantly lowered to 195 ~ 210 ℃.

However, conventional catalyst filling reformers have separate filters (not shown) for confining the catalyst materials therein, and such separate filters are not suitable for small or thin reformers with microchannels. It was to have.

The present invention is to solve the above conventional problems, the object of which is to uniformly fill the catalyst in the microchannel of the reforming unit to increase the reaction surface area of the fuel gas and the catalyst to obtain a high efficiency reforming effect The present invention provides a reformer having a catalytic filter in a microchannel.

In addition, the present invention provides a reformer having a catalytic filter in a microchannel capable of achieving a high efficiency reforming effect while achieving a compact structure and miniaturizing a fuel cell and increasing power output density.

In addition, the present invention is to provide a reformer having a catalytic filter in the micro-channel that can be made very simple, the manufacturing cost can be significantly reduced accordingly.

In order to achieve the above object, the present invention provides a reformer for use in a fuel cell,

Board;

A channel formed on the substrate;

A catalyst filter formed to hold a catalyst in the channel;

A particulate catalyst packed in the channel; And

A cover covering the channel;
The cover includes a fuel inlet for providing liquid fuel to the fuel inlet side; A hydrogen outlet for discharging hydrogen generated by reforming the fuel gas to the outside; And a catalyst inlet for filling particulate reforming catalyst in the reforming unit, thereby providing a reformer having a catalyst filter in the microchannel, wherein the fuel gas passes through the catalyst in the channel to reform the catalyst. .

And the present invention preferably provides a reformer having a catalyst filter in the micro-channel, characterized in that the catalyst filter comprises a plurality of protrusions protruding from the substrate and the gap formed therebetween.

The present invention also preferably provides a reformer with a catalytic filter in the microchannel, wherein the protrusions protrude in a row from the substrate, the height of which corresponds to the depth of the channel.

And the present invention preferably provides a reformer having a catalytic filter in the micro-channel, characterized in that the projections protrude in a plurality of rows from the substrate, the gap between adjacent rows are offset from each other.

delete

And the present invention preferably provides a reformer having a catalyst filter in the micro-channel, characterized in that the catalyst filter comprises a plurality of protrusions protruding from the cover and the gap formed therebetween.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

The reformer 1 according to the preferred embodiment of the present invention has a substrate 10 having a channel formed therein, as shown in FIG. 4. The substrate 10 may be made of silicon, metal, glass, ceramic, heat-resistant plastic, and the like, and various concave channels and partition walls are formed on one surface of the substrate 10 by using a MEMS (Micro Electro Mechanical Systems) process. It is formed.

Therefore, the fuel introduction portion 20, the evaporation portion 30, and the reforming portion 40 are disposed in the concave channel formed on one side of the substrate 10.

As shown in FIGS. 4 and 7, the fuel introduction unit 20 for introducing fuel into the channel of the substrate 10 is formed at one side of the substrate 10, and the fuel introduction unit 20 is provided. ) Is a fuel inlet 110 is formed in the cover 100 which is covered on the upper portion of the substrate 10 to supply methanol as a liquid fuel in the channel to supply liquid fuel.

Subsequently, the evaporation unit 30 is formed to be connected to the fuel introduction unit 20 to heat the liquid fuel and vaporize it into a gaseous state. The evaporation unit 30 is to vaporize the fuel in the liquid state so that the reforming reaction is satisfactorily achieved, and is located in the fuel introduction unit 20 in succession.

The evaporation unit 30 is provided with a heating means 36 as a heat source as a portion of the fuel, that is, an aqueous methanol solution is converted from a liquid to a gas, the heating means 36 is shown in FIG. An electrical resistance circuit is formed in a pattern on the lower surface of the substrate 10 to heat the evaporation portion 30 on the upper side through the substrate 10.

In addition, the present invention includes a bubble removing means 32 to impart a flow resistance to the fuel in the liquid state in the evaporation unit 30 to remove bubbles and vaporize.

The bubble removing means 32 is composed of a plurality of protrusions in the form of islands, and these protrusions are made to suppress the internal pressure increase by blocking the channel of the bubbles of fuel generated when gas is converted from the liquid.

Such protrusions have a structure in which a plurality of protrusions protrude throughout the evaporation unit 30 so as to be quickly extinguished when bubbles are generated in the evaporation unit 30, and if the evaporation unit 30 is formed in a channel form, the evaporation is performed. In the case where bubbles are generated at the corners of the part 30, the pressure may not be easily removed only by the inflow pressure of the fuel gas to be pushed behind. However, if the bubble removing means 32 in the evaporator 30 in the form of a projection, bubbles generated between the projections can be easily removed by the projections while moving freely.

In addition, in the present invention, a reforming portion 40 is formed on the downstream side of the evaporation portion 30 to form a flow passage 42 through which the fuel passes in the substrate 10 and to reform the fuel into hydrogen gas through an endothermic reaction. do. The reforming part 40 is disposed on the other side of the substrate 10 and formed on the downstream side of the evaporation part 30, and the flow path 42 is connected to the evaporation part 30 through an outlet. In addition, the flow passage 42 of the reforming portion 40 is partitioned by a plurality of partitions 44.

Accordingly, the flow passage 42 of the reforming portion 40 is formed in the entire area of the evaporation portion 30, and the particulate catalyst for reforming fuel gas into hydrogen gas in the flow passage 42 of the reforming portion 40. (46) is filled structure.

In the reforming unit 40, the fuel is converted into hydrogen-rich reforming gas by a catalytic reaction. As the particulate catalyst 46 of the reforming unit 40, Cu / ZnO or Cu / ZnO / Al ₂ O ₃ The catalyst 46 is held in the space in the reforming section 40 by catalyst filters 50 formed to hold the catalyst 46 in the flow passage 42. The catalyst filter 50 may be preferably formed at the inlet side and the outlet side of the flow passage 42.

In this way, the catalyst 46 is reformed to hydrogen by allowing fuel gas to flow between the particles in the flow passage 42 of the reforming section 40.

As shown in FIG. 6, the catalyst filters 50 provided in the reforming unit 40 may include particles of the catalyst 46 as an evaporation unit 30 in front of the reforming unit 40, or the reforming unit 40. It may be formed in a large size that does not escape to the hydrogen discharge portion 60 side of the rear side.

That is, the catalyst filter 50 includes a plurality of protrusions 52 protruding from the substrate 10 and gaps 54 formed therebetween, and the gap 54 is larger than the particle size of the catalyst 46. It is formed small, preferably the gap 54 is 10 ~ 35㎛, the diameter of the catalyst 46 particles is 50 ~ 200㎛.

When the gap 54 is formed to be smaller than 10 μm, the flow resistance of the fuel gas may be increased to reduce the processing capacity excessively. When the gap 54 is larger than 35 μm, the gap 54 may be broken and separated from the catalyst 46 particles. The fine particles are excessively discharged to the evaporation unit 30 and the hydrogen discharge unit 60 side is undesirable.

The protrusions 52 may have a size of about 100 μm × 100 μm, and the protrusions 52 of the catalytic filter 50 preferably protrude in a line from the substrate 10, and the height of the protrusions 52 may be increased. The structure corresponds to the depth of 42. By such a configuration, the catalyst 46 particles can be stably held in the reforming section 40.

Also, the projections 52 of the catalytic filter 50 protrude as a plurality of rows from the substrate 10, as shown in FIG. 6B, and the gaps 54 between adjacent rows are offset from each other. ) Is made of a structure. Through such a structure, the outflow of the catalyst 46 particles from the reforming unit 40 can be more stably prevented.

Meanwhile, the reforming unit 40 reforms a hydrocarbon-based fuel such as methanol to hydrogen gas through a reaction of the catalyst 46 accompanying an endothermic reaction, and a heat source required in this process is formed on the lower side of the substrate 10. Through the heating means 48. The heating means 48 of the reforming portion 40 has an electrical resistance circuit formed in a pattern on the lower surface of the substrate 10 to heat the reforming portion 40 on its upper side through the substrate 10. In addition, the heating unit 36 of the evaporator 30 may be formed in a single electrical resistance circuit pattern.

As shown in FIG. 5, the heating means 48 of the reforming part 40 is formed on the lower surface of the substrate 10 to change the temperature of the reforming part 40 through the substrate 10 to a predetermined temperature, Preferably maintained at a temperature between 250-290 ° C.

In addition, the present invention includes a cover 100 covering a channel of the substrate 10. The cover 100 is made of the same material as the substrate 10 or pyrex glass, and is bonded to the substrate 10 to form the evaporation portion 30 and the modified portions 40 therein. do.

The cover 100 is provided with a fuel inlet 110 for providing liquid fuel to the fuel inlet 20 side, and has a hydrogen outlet 120 for discharging the hydrogen generated by the reformed fuel gas to the outside. In addition, the catalyst injection hole 130 for filling the reforming catalyst 46 of the particulate form in the reforming portion 40 is formed.

In addition, such a cover 100 preferably forms a concave space or channel so as to correspond to the space or channel of the evaporation unit 30 and the reforming unit 40 so that the substrate 10 and the cover 100 are formed therein. The space or channel size to be formed can be made larger.

The reformer 1 according to the present invention configured as described above has an evaporation unit 30 and a reforming unit 40 formed therein, as shown in FIG. 7, and has an inlet side and an outlet side of the reforming unit 40. In the state where the catalyst filters 50 are formed, the particles of the catalyst 46 are filled in the internal flow passage 42 of the reforming unit 40.

In this case, the catalyst 46 particles are made through the catalyst inlet 130 provided in the cover 100, and the catalyst inlet 130 using the syringe 140 containing the catalyst 46 particles mixed in water. ) And the catalyst 46 particles are filled with water, and the catalyst 46 particles are filled together with water in the flow path 42 in the reforming portion 40, and the water is reformed through the catalyst filter 50. As shown in FIG. 8, only the particles of the catalyst 46 remain filled in the internal space of the reforming unit 40.

As such, the catalyst 46 particles are dried in the state where they are filled in the reforming unit 40, and then the catalyst inlet 130 is blocked to complete the reformer 1 of the present invention.

In the reformer 1 according to the present invention configured as described above, the fuel in the liquid state enters into the fuel inlet 20 of the substrate 10 through the fuel inlet 110 of the cover 100, and is arranged successively. Introduced into the evaporation unit 30.

The fuel gas thus introduced is vaporized at a temperature necessary for the reforming operation in the evaporator 30, that is, a temperature between 250-290 ° C.

Therefore, the evaporation unit 30 is converted from the liquid to the gas, and in the middle, the bubble removing means 32 make a protruding protrusion like an island to effectively remove the bubbles appearing when the liquid is converted to gas to evaporate. It is possible to prevent the pressure increase in the unit 30 and to increase the heat transfer efficiency.

Then, the vaporized fuel gas is introduced into the reforming portion 40 formed on the downstream side of the evaporation portion 30, and is evaporated through the catalyst filter 50 provided at the inlet side of the reforming portion 40. It is introduced into the reforming unit 40 side from the unit 30, undergoes a catalytic reaction accompanied by an endothermic reaction in the reforming unit 40, and is reformed with hydrogen gas at a temperature between 250-290 ° C in this process.

In addition, the reformed hydrogen gas flows toward the hydrogen discharge unit 60 and is discharged to the outside of the reformer 1 through the hydrogen discharge port 120 provided in the cover 100 and used as a raw material gas of the fuel cell. will be.

As described above, according to the present invention, a catalyst filter can be formed on the inlet side and the outlet side of the reforming subchannel, and the catalyst can be uniformly packed in the microchannel of the reforming portion to increase the reaction surface area of the fuel gas and the catalyst. Modification effect of efficiency can be obtained.

In addition, since the present invention can obtain a high efficiency reforming effect using the filling catalysts while having a compact structure, the fuel cell can be miniaturized and the power output density can be increased.

In addition, the present invention can be made in the same process at the time of forming the evaporation section and the reforming sub-channel as the catalyst filters are integrally formed on the substrate, the manufacturing process can be made very simple, thereby reducing the manufacturing cost significantly have.

While the invention has been shown and described with respect to specific embodiments thereof, it has been described by way of example only to illustrate the invention, and is not intended to limit the invention to this particular structure. Those skilled in the art will appreciate that various modifications and changes of the present invention can be made without departing from the spirit and scope of the invention as set forth in the claims below. Nevertheless, it will be clearly understood that all such modifications and variations are included within the scope of the present invention.

Claims (6)

In the reformer used for fuel cells, Board; A channel formed on the substrate; A catalyst filter formed to hold a catalyst in the channel; A particulate catalyst packed in the channel; And A cover covering the channel; The cover includes a fuel inlet for providing liquid fuel to the fuel inlet side; A hydrogen outlet for discharging hydrogen generated by reforming the fuel gas to the outside; And a catalyst inlet for filling particulate reforming catalysts in the reforming unit, and reforming the fuel gas through the catalyst in the channel to form a reforming catalyst. The reformer of claim 1, wherein the catalyst filter includes a plurality of protrusions protruding from the substrate and gaps formed therebetween. 3. The reformer of claim 2, wherein the protrusions protrude in a row from the substrate, the height of which corresponds to the depth of the channel. 3. The reformer of claim 2, wherein the protrusions protrude from the substrate in a plurality of rows, and the gaps between adjacent rows are offset from each other. delete The reformer of claim 1, wherein the catalyst filter includes a plurality of protrusions protruding from the cover and gaps formed therebetween.

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