JP3789706B2 - CO conversion unit and polymer electrolyte fuel cell power generation system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a CO conversion unit and a polymer electrolyte fuel cell power generation system suitable as a small power supply system for home use.
[0002]
[Prior art]
In recent years, a reformer that reforms a fuel gas such as natural gas or city gas into hydrogen, a CO converter that transforms carbon monoxide, a CO remover that removes carbon monoxide, and a fuel that generates electricity using the hydrogen A polymer electrolyte fuel cell power generation system including a battery has been proposed. Conventional fuel cell power generation systems are generally large-sized, and in addition to the above system, a space is required to install a case in which the control system, water tank, and auxiliary equipment including various pumps are separately stored. Therefore, it is difficult to apply it to a household power supply system as it is.
[0003]
[Problems to be solved by the invention]
In the conventional structure, the CO converter that converts carbon monoxide and the heat exchanger that cools the reformed gas introduced into the CO converter are separate, and the CO converter has an independent case. In addition, since the combustion device is attached to the case, the size of the device itself is increased, and it is difficult to store the device in a compact case in a compact manner like a household power supply system.
[0004]
Accordingly, an object of the present invention is to provide a CO conversion unit and a polymer electrolyte fuel cell power generation system using the same, which can solve the problems of the conventional techniques described above and can be reduced in size and size.
[0005]
[Means for Solving the Problems]
According to the first aspect of the present invention, a CO converter that converts carbon monoxide and a heat exchanger that cools the reformed gas introduced into the CO converter have an integrated structure, and the heat exchanger is integrated. The CO transformer is housed in a single case, a combustion device is provided at the bottom of the case, the inside of the case forms a passage for the combustion gas of the combustion device, and this combustion gas is exhausted through an exhaust port at the top of the case. It is characterized by the above.
[0006]
The invention described in claim 2 is the one described in claim 1, characterized in that the heat exchanger is a water heat exchanger .
[0007]
A third aspect of the invention is characterized in that, in the first or second aspect of the invention, the integral structure is an integral sleeve structure .
[0008]
The invention according to claim 4 is a reformer that reforms hydrogen by chemically reacting a fuel gas such as natural gas or city gas, a CO converter that converts carbon monoxide, and CO that removes carbon monoxide. In a polymer electrolyte fuel cell power generation system including a remover and a fuel cell that generates power using hydrogen, a CO converter and a heat exchanger that cools the reformed gas introduced into the CO converter are integrated. The CO converter with this heat exchanger integrated is housed in a single case, and a combustion device is provided at the bottom of the case. The inside of the case forms a combustion gas passage of the combustion device. The gas is exhausted through an exhaust port at the top of the case .
[0009]
The invention according to claim 5 is the invention according to claim 4, wherein the heat exchanger is a water heat exchanger .
[0010]
A sixth aspect of the invention is characterized in that, in the fourth or fifth aspect of the invention, the integral structure is an integral sleeve structure .
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[0013]
In FIG. 1, reference numeral 100 indicates a building, and commercial power is supplied to the building 100 via a low piezoelectric lamp wire 101, a watt hour meter 102, and a distribution board 103. The commercial power is supplied to the air conditioner 105, the television 106, and the like via the first cable 104 indicated by a thin line.
[0014]
On the other hand, in the present embodiment, a polymer electrolyte fuel cell power generation system (polymer electrolite fuel cell: PEFC device) S constituting a small household power supply system is installed outside the building 100.
[0015]
As shown in FIG. 2, this small household power supply system S includes a heat recovery device in addition to the PEFC device. This heat recovery apparatus has a hot water storage tank 112 and an ion exchange resin 125, and city water is supplied to the ion exchange resin 125 through a water pipe. This city water is made pure water with an ion exchange resin 125 and supplied to a water tank 21 (FIG. 3) described later. The PEFC device has a fuel supply device (reformer, CO converter, CO remover) 121.
[0016]
This fuel supply device 121 is supplied with fuel gas such as natural gas, city gas, methanol, LPG, butane, etc., and further supplied with water from a water tank 21 (FIG. 3) described later to generate hydrogen. Is done. This hydrogen is supplied to the fuel cell 6 where the hydrogen and oxygen in the air are chemically reacted to generate electricity. Reference numeral 123 denotes a control device that controls power generation control.
[0017]
This electric power is boosted to 180V through the DC / DC converter 124 and sent to the grid interconnection inverter 111. From here, the personal computer 108, the lighting 109, the refrigerator through the second cable 107 shown by a thick line in FIG. 110 or the like. This fuel cell power generation system S is connected to a commercial power source via a grid interconnection inverter 111.
[0018]
In this small power supply system S, heat is generated in the process of power generation, so hot water is generated from city water using this heat, and this hot water is stored in the hot water tank 112 as shown in FIG. As shown in FIG. 1, this hot water is supplied to a bath 113, a kitchen 114, and the like. This hot water tank 112 is installed outside the building 100.
[0019]
Next, the polymer electrolyte fuel cell power generation system (small household power supply system) S according to this embodiment will be described with reference to FIG.
[0020]
In this small household power supply system S, a fuel gas 1 such as natural gas or city gas is supplied to a desulfurizer 2 where sulfur components are removed from the fuel gas. The fuel gas that has passed through the desulfurizer 2 is boosted by the booster pump 10 and supplied to the reformer 3. In the reformer 3, a reformed gas containing hydrogen, carbon dioxide, and carbon monoxide is generated. The gas that has passed through the reformer 3 is supplied to a CO converter 4 where carbon monoxide contained in the reformed gas is converted into carbon dioxide.
[0021]
The gas that has passed through the CO converter 4 is supplied to a CO remover 5 where unconverted carbon monoxide in the gas that has passed through the CO converter 4 is removed.
[0022]
The hydrogen from which the carbon monoxide has been removed through the CO remover 5 is supplied to the solid polymer fuel cell 6. The fuel cell 6 includes a fuel electrode (anode) 6a, an air electrode (cathode) 6b, and a cooling unit 6c, and the hydrogen is supplied to the anode 6a. This hydrogen reacts with oxygen contained in the air supplied to the cathode 6b through the fan 11 to generate electric power.
[0023]
The reformer 3 has a burner 12, to which raw fuel is supplied via a pipe 13, air is supplied via a fan 14, and unreacted hydrogen passed through an anode 6a via a pipe 15. Is supplied.
[0024]
When the system is started, raw fuel is supplied to the burner 12 through the pipe 13 and air is supplied through the fan 14. When the system is stable after the start, the supply of raw fuel is cut off. The unreacted hydrogen that has passed through the anode 6 a is supplied to the burner 12 through the pipe 15.
[0025]
In the above reformer 3, CO converter 4, CO remover 5, and fuel cell 6, a chemical reaction having a predetermined reaction temperature is performed. Since the chemical reaction in the reformer 3 is an endothermic reaction, the chemical reaction is performed while always being heated by the burner 12.
[0026]
In addition, since the chemical reaction performed in the CO converter 4 and the CO remover 5 is an exothermic reaction, for example, the CO remover 5 burns a burner (not shown) only when the system is started to generate combustion gas. The temperature of the CO remover 5 is raised to the reaction temperature by the heat of the combustion gas generated at this time, and after the temperature is raised to the reaction temperature, cooling is performed so as not to raise the temperature beyond the reaction temperature due to the heat of the exothermic reaction. Done.
[0027]
In the fuel cell 6, an electrochemical reaction is performed, and heat is generated by the activation overvoltage, concentration overvoltage, and resistance overvoltage during the electrochemical reaction.
[0028]
The heat exchanger 18, the CO converter 4, the CO remover 5, the CO remover 5 and the fuel cell 6, and the exhaust system 26 of the fuel cell 6 are respectively connected to the reformer 3 and the CO converter 4. 19, 20, and 27 are connected.
[0029]
The water in the water tank 21 is circulated through the heat exchangers 18, 19 and 20 through the pumps 23, 24 and 25. With these waters, the reformer 3, the CO converter 4, the CO remover. Each of the gases having passed through 5 is cooled. Water in the hot water storage tank 112 (FIG. 2) circulates in the heat exchanger 27 via a pump 28.
[0030]
Water in the water tank 21 circulates in the cooling unit 6c of the fuel cell 6 via the pump 48, and the fuel cell 6 is cooled with this water.
[0031]
The heat exchanger 17 is connected to the exhaust system 31 of the reformer 3, and when water in the water tank 21 is supplied via the pump 22, the heat exchanger 17 vaporizes the water vapor. It is mixed with raw fuel and supplied to the reformer 3.
[0032]
In addition to the heat exchanger 17, another heat exchanger 32 is connected to the exhaust system 31, and water in the hot water storage tank 112 is circulated through the pump 33 to the heat exchanger 32. Waste heat recovery is performed.
[0033]
The system includes a process gas (PG) burner 34.
[0034]
Since the reformed gas that has passed through the reformer 3, the CO converter 4, and the CO remover 5 is not stable at the time of starting the system, this gas can be supplied to the fuel cell 6 until it is stabilized. Can not. Therefore, until each reactor is stabilized, the gas in an unstable state is guided to the PG burner 34 and burned. And after each reactor is stabilized, it introduces into the fuel cell 6 and performs electric power generation. Unreacted gas that could not be used for power generation in the fuel cell 6 is initially introduced into the PG burner 34 and combusted, and after the system of this system is stabilized, it is introduced into the burner 12 of the reformer 3 and combusted.
[0035]
The control system of the PG burner 34 will be described. After the activation of this system, the on-off valve 91 is closed and the reformed gas passes through the pipe 35 and the on-off valve 36 until the reactors are stabilized in temperature. 34. When each reactor is stabilized in temperature, this time, until the temperature of the fuel cell 6 is stabilized, the on-off valve 91 is opened, the on-off valve 92 is closed, and the reformed gas is supplied to the pipe line 38 and the on-off valve 39. Is supplied to the PG burner 34 and burned there. When the temperature of the fuel cell 6 is stable and power generation is performed continuously, the on-off valves 91 and 92 are opened, the on-off valves 36 and 39 are closed, and unreacted gas passing through the fuel cell 6 passes through the pipe line 15. Then, it is supplied to the burner 12.
[0036]
A heat exchanger 46 is connected to the exhaust system 45 of the PG burner 34, and water in the hot water storage tank 112 is circulated through the heat exchanger 46 via a pump 47.
[0037]
A heat exchanger 41 is connected between the water tank 21 and the hot water storage tank 112, and water in the water tank 21 circulates through the heat exchanger 41 via a pump 42. Water circulates.
[0038]
By the heat exchange in the heat exchanger 41, the temperature of the water in the hot water storage tank 112 rises and the temperature of the water in the water tank 21 falls.
[0039]
With the above configuration, the small household power supply system S takes the form of a cogeneration system, so that energy can be effectively utilized.
[0040]
Accordingly, high overall thermal efficiency is obtained, so that the amount of raw fuel consumed is reduced and the amount of carbon dioxide emitted is reduced.
[0041]
FIG. 4 shows the structure of the reformer 3, the CO converter 4, and the CO remover 5.
[0042]
The reformer 3 is supplied with a mixture of the fuel gas pressurized by the booster pump 10 (FIG. 3) and the steam pumped by the pump 22 (FIG. 3) and steamed by the heat exchanger 17. The The supplied gas enters the preheating section 301A of the reformer main body 301, is preheated through one pipe line 302A of the preheating section 301A, and then enters the next reforming section 301B. The gas that has entered the reforming section 301B is activated by the catalyst layer 303 filled therein to become a reformed gas, and this reformed gas is discharged downstream through the other pipe 302B of the preheating section 301A. Is done. Since the fuel supply system and air supply system to the burner 12 are as described above, description thereof will be omitted.
[0043]
The fuel gas reformed through the reformer 3 sequentially flows into the downstream CO conversion unit 60 and the CO removal unit 80.
[0044]
The CO conversion unit 60 of the present embodiment connects the CO converter 4 and the heat exchanger 18 that cools the reformed gas introduced into the CO converter 4 vertically in the axial direction, and these are made of stainless steel. The stainless steel sleeve 61 is integrated by a sleeve 61 and accommodated in a single case 62.
[0045]
Inside the stainless steel sleeve 61, a pair of support plates 63, 64 having a metal mesh or a large number of holes are provided, and a copper-based catalyst layer 65 is filled between the pair of support plates 63, 64, for example. Yes.
[0046]
Inside the sleeve 61, the heat exchanger 18 is provided above the catalyst layer 65 with a wide space 66. This heat exchanger 18 cools the reformed gas.
[0047]
A combustion device 78 is provided below the case 62, and the inside of the case 62 forms a passage for combustion gas of the combustion device 78, and this combustion gas is exhausted through an exhaust port 79 at the top of the case 62.
[0048]
The reformed gas cooled through the heat exchanger 18 is equalized in the wide space 66 and enters the catalyst layer 65 of the CO converter 4. Here, carbon monoxide contained in the reformed gas reacts with water vapor to be converted into carbon dioxide, and the carbon monoxide concentration in the reformed gas is reduced to about 1%. The active reaction is rapid at the inlet of the catalyst layer 65, and if the inlet temperature is high, the control of the CO converter 4 becomes difficult.
[0049]
In this embodiment, a temperature sensor (not shown) is provided in the wide space 66, and the amount of cooling water supplied to the heat exchanger 18 is adjusted so that the temperature here is about 200 ° C., for example. . The reformed gas that has passed through the CO converter 4 is sent to the above-described CO removal unit 80 through the pipe 50.
[0050]
The CO removal unit 80 of the present embodiment is configured such that the heat exchanger 19 and the CO remover 5 have an integral sleeve structure 88 and the integral sleeve structure 88 is housed in a single case 81. In this case 81, the CO remover 5 is located at the upper part, and a heat exchanger 19 for cooling the reformed gas introduced into the CO remover 5 is arranged at the lower part, and these are connected in an axial direction and integrated. Has been.
[0051]
The heat exchanger 19 is supplied with cooling water via a pump 24 (FIG. 3) to cool the reformed gas entering the CO remover 5.
[0052]
A pair of support plates 82 and 83 having a metal mesh or a large number of holes are provided inside the CO remover 5, and a noble metal / ruthenium-based catalyst layer 84 is filled between the pair of support plates 82 and 83. Yes.
[0053]
Even in this CO remover 5, the active reaction is rapid at the inlet of the catalyst layer 84, and the CO remover 5 runs away when the inlet temperature is high.
[0054]
In order to prevent this, for example, a temperature sensor (not shown) is provided in the inlet space 85 of the CO remover 5, and the amount of cooling water supplied to the heat exchanger 19 so that the temperature here becomes a predetermined temperature. It is desirable to adjust.
[0055]
A combustion device 91 is provided below the case 81, and the inside of the case 81 forms a passage for the combustion gas of the combustion device 91, and this combustion gas is exhausted through an exhaust port 92 at the top of the case 81.
[0056]
Next, the operation of the CO remover 5 will be described. In the present embodiment, air is introduced upstream of the heat exchanger 19 via the air pump 55 (FIG. 3).
[0057]
This air is mixed with the reformed gas that has passed through the CO converter 4, cooled by the heat exchanger 19, and enters the catalyst layer 84 of the CO remover 5. Here, carbon monoxide in the reformed gas is converted into carbon dioxide by a selective oxidation reaction (exothermic reaction), and the carbon monoxide concentration of the reformed gas is reduced to about 10 ppm. The reformed gas with the reduced carbon monoxide concentration passes through the conduit 93 and is sent to the fuel cell 6.
[0058]
Since the above-described CO treatment is an exothermic reaction, each burner 78, 91 is burned only when the system is started. When the system is started, fuel from the fuel supply source 1 (FIG. 3) is supplied to each burner 78, 91, and the temperature detected by a temperature sensor (not shown) installed in each catalyst layer 65, 84 is Fuel supply is performed until the temperature reaches 200 to 300 ° C.
[0059]
In the above configuration, when these are applied to a small household power supply system S, the reformer 3, the CO converter 4 for converting carbon monoxide, the CO remover 5 for removing carbon monoxide, and hydrogen are used. As shown in FIG. 2, the fuel cell 6 for generating power, its control system, the water tank 21, and the auxiliary machines including various heat exchangers 18, 19 and pumps are stored together in one outer case. It is desirable to do.
[0060]
In this embodiment, the CO conversion unit 60 is configured by connecting the CO converter 4 and the heat exchanger 18 in the axial direction, integrating them by a sleeve 61, and housing the sleeve 61 in a single case 62. Therefore, the CO conversion unit 60 can be reduced in size and size. Further, since the CO removal unit 80 is configured by housing the CO removal unit 5 in which the heat exchanger 19 is integrated in a single case 81, the CO removal unit 80 can be made compact and compact. Therefore, the heat exchanger 18 and the CO transformer 4, the heat exchanger 19 and the CO remover 5 can be efficiently stored in the outer case, and the small household power supply system S can be designed compactly.
[0061]
As mentioned above, although this invention was demonstrated based on one Embodiment, it is clear that this invention is not limited to this.
[0062]
【The invention's effect】
In the present invention, a CO converter that converts carbon monoxide and a heat exchanger that cools the reformed gas introduced into the CO converter have an integral structure, and the CO converter that integrates the heat exchanger is provided. It is housed in a single case, a combustion device is provided at the bottom of the case, the inside of the case forms a passage for combustion gas of the combustion device, and the combustion gas is exhausted through an exhaust port at the top of the case. since the, these small compact can be achieved.
[0063]
Therefore, the heat exchanger and the CO transformer can be efficiently accommodated in, for example, an outer case, and the small household power supply system can be downsized.
[Brief description of the drawings]
FIG. 1 is a system diagram when a polymer electrolyte fuel cell power generation system according to the present invention is installed in a home.
FIG. 2 is a diagram showing an outdoor portion of FIG. 1;
FIG. 3 is a circuit diagram showing an embodiment of a polymer electrolyte fuel cell power generation system.
FIG. 4 is a diagram showing the structure of a reformer, a CO converter, and a CO remover.
[Explanation of symbols]
3 reformer 4 CO converter 5 CO remover 18, 19 Hydro-heat exchanger 60 CO converter unit 61 Sleeve 62 Case 78 Combustion device 79 Exhaust port 80 CO removal unit 81 Case 91 Combustion device 92 Exhaust port S Solid polymer type Fuel cell power generation system

Claims (6)

The CO converter that converts carbon monoxide and the heat exchanger that cools the reformed gas introduced into the CO converter have a single structure, and the CO converter that integrates the heat exchanger is a single case. And a combustion device is provided at the bottom of the case, the inside of the case forms a combustion gas passage of the combustion device, and the combustion gas is exhausted through an exhaust port at the top of the case.
CO transformation unit characterized by this. CO conversion unit according to claim 1, wherein said heat exchanger is a water heat exchanger, characterized in that. The integral structure is integral sleeve construction, according to claim 1 or 2 SL placing CO conversion unit, characterized in that. Electricity is generated by hydrogen using a reformer that chemically reforms fuel gas such as natural gas or city gas into hydrogen, a CO converter that converts carbon monoxide, a CO remover that removes carbon monoxide, and hydrogen In a polymer electrolyte fuel cell power generation system comprising a fuel cell,
The CO converter and a heat exchanger that cools the reformed gas introduced into the CO converter have an integrated structure, and the CO converter integrated with the heat exchanger is housed in a single case. A solid polymer characterized in that a combustion device is provided at the bottom of the case, the inside of the case forms a passage for the combustion gas of the combustion device, and this combustion gas is exhausted through an exhaust port at the top of the case Type fuel cell power generation system. The solid polymer fuel cell power generation system according to claim 4, wherein the heat exchanger is a water heat exchanger . The integral structure is integral sleeve construction, according to claim 4 or 5 a polymer electrolyte fuel cell power generation system, wherein the.

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