JP6079988B2 - Fuel cell cogeneration system - Google Patents

Description

The present invention relates to a fuel cell cogeneration system comprising a desulfurizer.

An example of a fuel cell cogeneration system is described in Patent Document 1.
The cogeneration system described in this document includes a desulfurization device for removing sulfur components from fuel gas that is a raw material of a fuel cell. This is because the sulfur component in the fuel gas adversely affects the cell module and the fuel reforming catalyst. The aforementioned desulfurization apparatus is a combination of a desulfurizer filled with a desulfurizing agent and a heating means for heating the degreasing agent. For example, zeolite-based desulfurization agents are used, but such desulfurization agents also have the property of adsorbing moisture in fuel gas, and adsorbing moisture significantly reduces the adsorption performance for sulfur compounds. To do. On the other hand, if the desulfurizing agent is heated and the temperature is set to a predetermined temperature or higher, it is possible to avoid moisture adsorption when a fuel gas with a high dew point is supplied and to suppress performance deterioration of the desulfurizing agent. It is. The heating means of the desulfurization apparatus described above is used to perform such heating.

  However, in the past, as described below, there is still room for improvement.

That is, in Patent Document 1, as a specific example of the means for heating the desulfurizing agent, a hot water storage tank attached to the cogeneration system is connected to the desulfurizer by piping and a predetermined pump is used. Means for supplying hot water from the hot water storage tank to the desulfurizer is described.
However, in such a means, in order to heat the desulfurizing agent, it is necessary to operate a pump for supplying hot water in the hot water storage tank to the desulfurizer, resulting in power consumption accompanying the pump operation. From the viewpoint of operating the cogeneration system efficiently, there is still room for improvement in operating a predetermined pump and consuming electric power only for the purpose of heating the desulfurizing agent. In addition, since the above-described pump must be provided, the equipment cost increases accordingly.

  Conventionally, unlike the above, there is also means for heating the desulfurizing agent using an electric heater. However, such means requires a separate electric heater and also consumes a large amount of power when driving the electric heater. Therefore, there is still room for improvement.

JP 2011-96400 A

The present invention has been conceived under the circumstances described above, and heating of the desulfurizing agent for desulfurizing the fuel gas is energy efficient and without using a dedicated heating device or the like. The problem is to provide a fuel cell cogeneration system that can be performed appropriately.

  In order to solve the above problems, the present invention takes the following technical means.

Fuel cell cogeneration system further provided in the present invention, a fuel cell power generation part, and the hot water storage tank for storing hot water which is heated by utilizing the waste heat from the fuel cell power generation part, inside the desulfurizing agent And a desulfurizer for desulfurizing the fuel gas supplied to the fuel cell power generation unit, and means for heating the desulfurizing agent using the hot water of the hot water storage tank. In the fuel cell cogeneration system, as the means for heating the desulfurizing agent, a structure in which the desulfurizer is provided in contact with or close to the hot water storage tank, or accommodated in the hot water storage tank is used. is and, a temperature detecting means for detecting a hot water heating is possible auxiliary heat source machine, the desulfurizer of temperature, or the temperature of the portion corresponding to the desulfurizer of the hot water storage tank When the temperature detected using this temperature detecting means falls below a predetermined temperature, the hot water from the hot water storage tank is prevented and the auxiliary heat source device is driven and heated by the auxiliary heat source device. Control means for executing an operation of discharging hot water or an operation of flowing hot water into the hot water storage tank is further provided .

According to such a configuration, as a result of heating the desulfurizing agent using the hot water of the hot water storage tank, it is possible to suppress the moisture adsorption to the desulfurizing agent and prevent the problem that the performance of the desulfurizing agent is deteriorated. The following effects can be obtained.
That is, in the present invention, unlike the prior art, it is not necessary to send the hot water in the hot water storage tank to the installation location of the desulfurizer using the pump. Therefore, the pump can be eliminated and the equipment cost can be reduced. Furthermore, since the power consumption accompanying the operation of the pump can be eliminated, the cogeneration system can be operated more energy-efficient than before.
Furthermore, heating of the desulfurizing agent can be appropriately continued so that the temperature of the desulfurizing agent does not drop below a predetermined temperature.

  In the present invention, preferably, the hot water is stored in the hot water storage tank from the upper part in the hot water storage tank, and the desulfurizer is provided in contact with or close to the upper part of the hot water storage tank. Or in the upper part of the hot water storage tank.

According to such a configuration, the following effects can be obtained.
Regarding the temperature distribution of the hot water in the hot water storage tank, the upper part in the hot water storage tank is the hottest in normal times. On the other hand, the desulfurizer is arranged corresponding to such a portion. Therefore, it becomes more preferable when the desulfurizer is heated to a high temperature for a long time.

  In the present invention, preferably, a heat insulating material covering the hot water storage tank is provided, and a concave portion is provided in a portion of the heat insulating material facing the hot water storage tank, and the desulfurizer is provided in the concave portion. Is housed.

  According to such a configuration, the desulfurizer can be heated in a state in which the heat released from the hot water in the hot water storage tank is contained in the concave portion provided in the heat insulating material. Therefore, it is possible to reduce heat dissipation loss and to heat the desulfurization agent in the desulfurizer more efficiently. Further, if the desulfurizer is supported by the concave portion of the heat insulating material, it is possible to eliminate the need to separately use a bracket for the desulfurizer.

  In the present invention, preferably, the desulfurizer is desulfurized inside a pipe wound around an outer periphery of the hot water storage tank or a pipe provided so that a part of the hot water storage tank enters from the outside. The composition is filled with an agent.

  According to such a configuration, the heat of the hot water in the hot water storage tank can be easily transmitted to the desulfurizer outside or inside the hot water storage tank while suppressing the bulk of the desulfurizer.

  Other features and advantages of the present invention will become more apparent from the following description of embodiments of the present invention with reference to the accompanying drawings.

(A) is a schematic explanatory drawing which shows an example of the fuel cell cogeneration system which concerns on this invention, (b) is Ib-Ib principal part sectional drawing of (a). FIG. 2 is an exploded cross-sectional view of a main part of a hot water tank unit constituting the fuel cell cogeneration system shown in FIG. 1. It is a flowchart which shows an example of the operation processing procedure of the control part with which the fuel cell cogeneration system shown in FIG. 1 was equipped. It is principal part plane sectional drawing which shows the other example of this invention. It is a principal part schematic perspective view which shows the other example of this invention, and its partial expanded sectional view. (A), (b) is a principal part schematic perspective view which shows the other example of this invention.

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

A fuel cell cogeneration system C shown in FIG. 1 is configured by combining a fuel cell system 1 and a hot water storage tank unit U having a hot water storage tank 3.
In the hot water storage tank unit U, a desulfurizer 4 for desulfurizing a fuel gas used as a raw fuel of the fuel cell system 1 is provided with a predetermined structure, which will be described later. There are features.

  The desulfurizer 4 has a configuration in which a desulfurization agent 41 is accommodated in a container 40 having a gas inlet 40a and an outlet 40b. The desulfurizing agent 41 is, for example, a metal-supporting zeolite system such as a silver-supporting Y-type zeolite, and is granular (including pellets). A filter 42 is appropriately provided in the container 40.

The fuel cell system 1 includes a fuel cell power generation unit 10 using, for example, an SOFC (solid oxide fuel cell) and a heat exchange unit 11 for exhaust heat recovery. The fuel cell system 1 and the desulfurizer 4 are connected to each other through a gas piping section 90, and a city gas or LPG or other fuel gas supplied to the gas supply port 91 is sent to the desulfurizer 4 for desulfurization. Processing is attempted. Thereafter, the fuel gas is sent toward the reformer 12 through the gas piping unit 90. The fuel cell power generation unit 10 is supplied with the fuel gas reformed by the reformer 12. A part of the fuel gas that has passed through the gas piping section 90 is also supplied to the burner 13 for heating the fuel gas reforming catalyst provided in the reformer 12.

  The heat exchange unit 11 for recovering exhaust heat recovers heat from the high-temperature exhaust gas discharged from the fuel cell power generation unit 10 and performs hot water heating using this heat. When the pump P of the hot water storage tank unit U is operated, the hot water in the hot water storage tank 3 is supplied to the heat exchanging unit 11 via the piping 60 a and is heated by the heat exchanging unit 11. The hot water heated by the heat exchange part 11 is returned to the upper part in the hot water storage tank 3 through the piping part 60b. Therefore, the hot water is stored in the hot water storage tank 3 sequentially from the upper side of the hot water storage tank 3.

  The hot water storage tank unit U is configured such that a hot water storage tank 3 and a heat insulating material 8 that covers the hot water storage tank 3 are accommodated in an outer case 7. The hot water storage tank unit U also includes an auxiliary heat source device 2 and a control unit 5 in addition to the desulfurizer 4 described above. In FIG. 1A, for convenience, the auxiliary heat source machine 2 and the control unit 5 are shown to be located outside the outer case 7, but these components are actually in the case 7, It is provided at a position avoiding the hot water storage tank 3 and the heat insulating material 8.

  A hot water discharge pipe 61 and a water intake pipe 62 are connected to the upper and lower parts of the hot water storage tank 3 via three-way valves V1 and V2. When a tip (not shown) connected to the hot water outlet 61 a of the hot water outlet pipe 61 is opened, hot water in the hot water storage tank 3 is used from the incoming water pipe 62 to the hot water storage tank 3. Then, the hot water can flow out to the hot water outlet pipe 61 and can be discharged from the hot water outlet 61a. The auxiliary heat source device 2 is for performing hot water heating when, for example, a shortage of heat in the hot water storage tank 3 occurs or when heating or hot water supply with a large amount of heat consumption is performed. The auxiliary heat source unit 2 has the same configuration as that of an instantaneous gas water heater, for example, and can perform rapid hot water heating.

  The heat insulating material 8 is for improving the heat retaining property of the hot water storage tank 3, and as the heat insulating material 8, a heat insulating material 8 (8A) for covering the upper end plate portion of the hot water storage tank 3 and a heat insulating material 8 for covering the trunk portion ( 8B, 8C). As clearly shown in FIG. 2, the heat insulating materials 8 </ b> B and 8 </ b> C are attached so as to sandwich the body portion of the hot water storage tank 3 from the left and right sides of the hot water storage tank 3. The heat insulating materials 8A and 8B are provided with concave portions 80a and 80b. When the heat insulating material 8 is mounted on the hot water storage tank 3, these concave portions 80 a and 80 b are connected to each other in the vertical direction, and the desulfurizer 4 is accommodated therein. The peripheral edges of the opening portions of the concave portions 80a and 80b are in contact with the outer surface of the hot water storage tank 3, whereby the concave portions 80a and 80b are substantially sealed space portions.

  As shown in FIG. 1, a part of the desulfurizer 4 is provided in contact with the outer surface of the hot water storage tank 3, but these may be in a non-contact state. Although the weight of the desulfurizer 4 is received by the heat insulating material 8B, if the material of the heat insulating material 8B is the foamed resin molded body described above, sufficient durability strength to support the desulfurizer 4 should be ensured. Is possible. The heat insulating material 8 is appropriately provided with a passage for passing the gas pipe 90 described above and the gas pipe having the gas supply port 91 at one end.

The control unit 5 is configured by using a microcomputer or the like, and executes operation control of each part of the hot water storage tank unit U. The hot water storage tank 3 is provided with a plurality of temperature sensors Sa for detecting hot water temperature (corresponding to an example of temperature detecting means in the present invention) at appropriate intervals in the vertical direction. The hot water temperature distribution in the hot water storage tank 3 can be grasped using the temperature sensor Sa, and the hot water temperature of the hot water storage tank 3 is controlled so that the desulfurizer 4 does not fall below a predetermined temperature. However, this point will be described later.

  Next, the operation of the fuel cell cogeneration system C will be described.

First, the desulfurizer 4 can be heated efficiently and continuously using the heat of the hot water in the hot water storage tank 3. For this reason, it is possible to prevent unreasonable condensation from occurring in the desulfurizer 4, and to suppress a problem that the performance of the desulfurizing agent 41 is deteriorated due to moisture adsorption of the desulfurizing agent 41.
On the other hand, in the present embodiment, unlike the prior art, it is not necessary to send hot water from the hot water storage tank 3 to the desulfurizer 4 using a pump, and the desulfurizer 4 may be fixedly arranged in the hot water storage tank unit U. Good. Therefore, the pump used in the prior art is unnecessary, and the consumption of electric energy required for the pump operation is eliminated, and the entire system can be operated efficiently. In addition, the circulation of the fuel gas in the gas piping unit 90 connecting the desulfurizer 4 and the fuel cell system 1 is appropriately performed using the gas supply pressure to the fuel gas supply port 91.

  The normal hot water distribution in the hot water storage tank 3 is the highest temperature distribution in the upper part of the hot water storage tank 3. On the other hand, since the desulfurizer 4 is provided adjacent to the upper part of the hot water storage tank 3, it becomes more preferable when the desulfurizer 4 is heated to a high temperature and appropriately. In particular, in this embodiment, since the desulfurizer 4 is in contact with the outer surface of the hot water storage tank 3 and there is direct heat transfer from the hot water storage tank 3 to the desulfurizer 4, the heating efficiency of the desulfurizer 4 is good. Further, the desulfurizer 4 is accommodated in the recessed portions 80 a and 80 b of the heat insulating material 8 and is surrounded by the heat insulating material 8, but the openings of the recessed portions 80 a and 80 b are blocked by the outer surface of the hot water storage tank 3. In addition, it is a substantially sealed space portion and has a structure for containing heat from the hot water storage tank 3. Therefore, based on such a structure, the desulfurizer 4 is heated more efficiently. If the desulfurizer 4 is accommodated and supported in the concave portions 80a and 80b, there is no need to use a dedicated bracket for the desulfurizer 4.

  The control unit 5 is configured to execute the following operation control. This operation will be described with reference to the flowchart of FIG.

  First, the controller 5 monitors the hot water temperature in the upper part of the hot water storage tank 3 constantly or at short cycle intervals based on a detection signal from the temperature sensor Sa (Sa ') (S1). Of course, the temperature by the temperature sensor Sa different from the temperature sensor Sa 'is also monitored. When it is found that the temperature detected by the temperature sensor Sa ′ has dropped below a predetermined first temperature T1, the hot water from the hot water storage tank 3 is stopped at that time, and the auxiliary heat source unit 2 and the pump P starts driving, and the operation of storing hot water heated by the auxiliary heat source device 2 in the hot water storage tank 3 is executed (S2: YES, S3, S4). Moreover, when there is a hot water request, the hot water heated by the auxiliary heat source device 2 is sent to the hot water request location. When it is desired to maintain the desulfurizer 4 at, for example, 40 ° C. or higher, the first temperature T1 is set to a temperature obtained by adding an appropriate margin value to, for example, 40 ° C. As a result of the above-described operation, when the temperature detected by the temperature sensor Sa ′ increases and reaches a predetermined second temperature (a temperature higher by an appropriate amount than the first temperature), at that time, the auxiliary heat source device 2 and the pump P The operation is stopped, and the hot water supply stop state from the hot water storage tank 3 is also released (S5: YES, S6).

According to the control described above, the desulfurizer 4 is appropriately prevented from dropping below a predetermined temperature (for example, 40 ° C.). In the construction of a gas pipe connected to the gas supply port 91, when moisture enters the gas pipe, fuel gas having a dew point of about 20 to 30 ° C. may be supplied to the gas supply port 91 for a long period of time. . If the desulfurizer 4 is continuously heated to, for example, 40 ° C. or higher, dew condensation in the desulfurizer 4 is prevented, and moisture adsorption of the desulfurizing agent 41 can be appropriately avoided. When the desulfurizing agent 41 is a metal-supported zeolite, the heating temperature is optimally about 80 ° C., and if it exceeds 150 ° C., the performance deteriorates and it is necessary to avoid such a temperature. The hot water temperature in the upper part of 3 is optimal for heating in the above-described range. In the normal state, the operation control shown in FIG. 3 is performed. On the other hand, when the operation of the fuel cell power generation unit 10 is started, the operation control for heating and maintaining the desulfurization agent 41 at about 80 ° C. is started. You may comprise.

  The operation control shown in FIG. 3 is performed using a temperature sensor Sa ′ attached to the hot water storage tank 3. Instead, a temperature sensor for detecting the temperature of the desulfurizer 4 is used. May be. In addition to being directly attached to the desulfurizer 4, this temperature sensor may be provided, for example, in the concave portions 80a and 80b.

  4 to 6 show another embodiment of the present invention. In these drawings, elements that are the same as or similar to those in the above embodiment are given the same reference numerals as in the above embodiment.

  In the embodiment shown in FIG. 4, the planar view shape of the desulfurizer 4 </ b> A is a substantially rectangular shape, but one side surface 4 a is a curved surface that can come into surface contact with the outer surface of the hot water storage tank 3. . According to such a configuration, it is possible to increase the amount of heat transfer from the hot water storage tank 3 to the desulfurizer 4A. As understood from the present embodiment, the shape of the desulfurizer can be changed as appropriate. In the present invention, the desulfurizer need not be brought into contact with the outer surface of the hot water storage tank as described above, and may be provided simply in proximity to the hot water storage tank. Even in such a case, the heat of the hot water in the hot water storage tank can be applied to the desulfurizer.

In the embodiment shown in FIG. 5, the desulfurizer 4 </ b> B is configured using a tubular body 40 </ b> B made of metal or the like wound around the hot water storage tank 3. More specifically, the pipe body 40B is formed in a spiral loop shape that can be wound around the hot water storage tank 3 by being bent, and the inside of the pipe body 40B is filled with a desulfurizing agent 41. Has been. A filter 42 is provided in the inner part of the gas inlet 40a and the outlet 40b of the tube body 40B.
According to this embodiment, the desulfurizer 4B can be attached to the outside of the hot water storage tank 3 so as not to be bulky. Further, the contact area (heat transfer area) between the hot water storage tank 3 and the desulfurizer 4B can be increased.

In the embodiment shown in FIGS. 6A and 6B, desulfurizers 4 </ b> C and 4 </ b> D are accommodated in the hot water storage tank 3. The desulfurizer 4C has a configuration in which a part of the metal pipe body 40C has a spiral loop shape and is filled with a desulfurizing agent (not shown). The helical loop-shaped part is arranged in the hot water storage tank 3. The desulfurizer 4 </ b> D has a configuration in which a desulfurizing agent is filled in a metal pipe body 40 </ b> D that is formed as a U-shaped tube and a part of which is inserted into the hot water storage tank 3.
In the present embodiment, since the desulfurizers 4C and 4D are in direct contact with the hot water in the hot water storage tank 3, the heating efficiency is further improved. Further, it is possible to prevent the desulfurizers 4C and 4D from being bulky outside the hot water storage tank 3. As understood from the present embodiment, in the present invention, the desulfurizer may be housed in a hot water storage tank.

The present invention is not limited to the contents of the above-described embodiment. The specific configuration of each part of the fuel cell cogeneration system according to the present invention can be modified in various ways within the intended scope of the present invention.

  The type of the desulfurizing agent is not limited to the metal-supported zeolite system, and other desulfurizing agents can be used. When a desulfurizing agent having a property that improves performance by heating or prevents performance deterioration is used, the intended effect of the present invention can be suitably obtained. Although it is preferable to arrange the desulfurizer at the upper part of the hot water storage tank or the upper part of the hot water storage tank, the desulfurizer can also be provided at other heights.

C Fuel cell cogeneration system U Hot water storage tank unit Sa Temperature sensor (temperature detection means)
DESCRIPTION OF SYMBOLS 1 Fuel cell system 2 Auxiliary heat source machine 3 Hot water storage tank 4, 4A-4D Desulfurizer 5 Control part (control means)
8 Heat Insulating Material 10 Fuel Cell Power Generation Unit 11 Heat Exchanger 41 for Waste Heat Recovery Desulfurization Agents 80a and 80b Concave Parts

Claims (4)

A fuel cell power generation unit;
A hot water storage tank for storing hot water heated using the exhaust heat from the fuel cell power generation unit;
A desulfurizer filled with a desulfurizing agent and for desulfurizing the fuel gas supplied to the fuel cell power generation unit;
Means for heating the desulfurizing agent using hot water in the hot water storage tank;
A fuel cell cogeneration system comprising:
As a means for heating the desulfurizing agent, the desulfurizer is provided in contact with or close to the hot water storage tank, or a structure in which the hot water storage tank is accommodated, is used .
Auxiliary heat source machine capable of hot water heating,
Temperature detection means for detecting the temperature of the desulfurizer or the temperature of the hot water storage tank corresponding to the desulfurizer;
When the temperature detected using this temperature detecting means falls below a predetermined temperature, the hot water from the hot water storage tank is prevented and the auxiliary heat source device is driven and heated by the auxiliary heat source device. Control means for executing an operation of discharging hot water or an operation of flowing the hot water into the hot water storage tank;
A fuel cell cogeneration system, further comprising: The fuel cell cogeneration system according to claim 1,
Storage of heated hot water in the hot water storage tank is configured to be performed from an upper part in the hot water storage tank,
The fuel cell cogeneration system, wherein the desulfurizer is provided in contact with or close to an upper portion of the hot water storage tank, or is accommodated in an upper portion of the hot water storage tank. A fuel cell cogeneration system according to claim 1 or 2,
Comprising a heat insulating material covering the hot water storage tank;
A fuel cell cogeneration system in which a concave portion is provided at a portion of the heat insulating material facing the hot water storage tank, and the desulfurizer is accommodated in the concave portion. A fuel cell cogeneration system according to any one of claims 1 to 3,
The desulfurizer has a configuration in which a desulfurizing agent is filled in a pipe wound around an outer periphery of the hot water storage tank, or a pipe provided so that a part of the hot water storage tank enters from the outside. A fuel cell cogeneration system.

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