JP2011096422A - Fuel cell cogeneration system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell cogeneration system which reduces the effect on the environment and sewage treatment. <P>SOLUTION: The fuel cell cogeneration system includes: a mixing section provided with a mixing tank 21 for mixing drainage from a condensed water treatment device 16 with water other than the drainage from the condensed water treatment device 16; and an outside drain pipe 22 for drain the mixed drainage mixed in the mixing section to the outside. In the fuel cell cogeneration system, a control section 9 for controlling operation of a mixing water supply means is also included so that water other than the drainage from the condensed water treatment device 16 is supplied to the mixing section at every predetermined time interval, thereby pH of the mixed drainage drained to the outside can be set in a predetermined range. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a fuel cell cogeneration system.

  In recent years, as next-generation energy, a plurality of fuel cells that can obtain electric power using hydrogen-containing gas (fuel gas) and air (oxygen-containing gas) are arranged electrically via a current collecting member. A cell stack device is configured by fixing cell stacks connected in series to a manifold for supplying fuel gas to a fuel cell, and a fuel cell module in which the cell stack device is stored in a storage container. Various fuel cell cogeneration systems combined with a hot water storage tank for storing hot water generated by using the fuel cell device provided and heat generated by power generation of the fuel cell device have been proposed.

  In such a fuel cell cogeneration system, it is necessary to drain excess water in the fuel cell cogeneration system, and a fuel cell cogeneration system for the purpose of simplifying a drainage line has been proposed (for example, a patent) Reference 1).

JP 2007-48654 A

  By the way, in the fuel cell cogeneration system, the quality of water discharged from the power generation unit may be deteriorated. In particular, a heat exchanger for exchanging heat between exhaust gas from the fuel cell and water, and a water tank for storing condensed water generated by heat exchange in the heat exchanger as water to be supplied to the reformer In the case of draining water (condensate) in which a gas such as carbon dioxide generated along with power generation of the fuel battery cell is drained to the outside, the pH of the water drained to the outside decreases, There is concern about the impact on the environment and the impact on sewage treatment when the water whose pH is lowered is drained to the outside.

  Therefore, an object of the present invention is to provide a fuel cell cogeneration system capable of reducing the influence on the environment and sewage treatment by setting the quality of water drained to the outside within a predetermined range. And

  A fuel cell cogeneration system according to the present invention includes a fuel cell that generates power using a fuel gas and an oxygen-containing gas, a reformer that generates fuel gas to be supplied to the fuel cell, and an exhaust gas from the fuel cell. A power generation unit comprising a heat exchanger for exchanging heat with water and a water tank for storing condensed water generated by heat exchange in the heat exchanger as water to be supplied to the reformer, and heat A hot water storage unit comprising a hot water storage tank for storing the water after replacement, a circulation pipe for circulating water between the heat exchanger and the hot water storage tank, drainage from the water tank and the water tank A mixing unit comprising a mixing tank for mixing water other than the waste water, mixing water supply means for supplying water other than the waste water from the water tank to the mixing unit, and the mixing unit Controls the operation of the mixing water supply means so as to supply water other than the waste water from the water tank to the mixing section at predetermined intervals, and an external drain pipe for discharging the mixed mixed waste water to the outside. And a control device.

  In such a fuel cell cogeneration system, the waste water from the water tank and the water other than the waste water from the water tank are mixed in the mixing section equipped with the mixing tank, and the mixed waste water is externally supplied via an external drain pipe. Even if the pH of the water drained from the water tank is low, mixing with water other than the drainage from the water tank lowers the pH of the mixed wastewater drained to the outside. Can be suppressed.

  Here, since a control device is provided for controlling the operation of the mixing water supply means so as to supply water other than the waste water from the water tank to the mixing unit at predetermined intervals, the mixing unit is periodically supplied with the water tank. Water other than the waste water is supplied. Thereby, it can suppress efficiently that the pH of the water drained outside falls, and the pH of the mixed waste water can be within a predetermined range. Thereby, it can be set as the fuel cell cogeneration system which can reduce the influence which acts on an environment or a sewage treatment.

  In the fuel cell cogeneration system of the present invention, the mixing water supply means is provided in a hot water storage tank drain pipe connecting the hot water storage tank and the mixing tank, and in the hot water storage tank drain pipe, and the hot water storage tank stores water. A hot water storage tank drain valve for draining the collected water to the mixing unit, and the control device supplies the water stored in the hot water storage tank to the mixing unit every predetermined time. It is preferable to control the operation of the hot water tank drain valve.

  In such a fuel cell cogeneration system, the mixing water supply means is provided in the hot water tank drain pipe connecting the hot water storage tank and the mixing tank, and the hot water tank drain pipe, and the water stored in the hot water storage tank is mixed. And a hot water tank drain valve for draining into the hot water tank, and a control device controls the operation of the hot water tank drain valve so that the water stored in the hot water tank is supplied to the mixing section every predetermined time. Thus, the pH of the mixed waste water can be more effectively set within the predetermined range.

  In the fuel cell cogeneration system of the present invention, the mixing water supply means connects the external water supply means for supplying water from the outside to the hot water storage tank, and the external water supply means and the mixing section. An external water supply pipe; and an external water adjustment valve provided in the external water supply pipe for adjusting the amount of water supplied from the external water supply means to the mixing unit. It is preferable to control the operation of the external water regulating valve so that water from the outside is supplied to the mixing unit at predetermined time intervals.

  In such a fuel cell cogeneration system, the mixing water supply means includes an external water supply means for supplying water from the outside to the hot water storage tank, and an external water supply pipe connecting the external water supply means and the mixing section. And an external water regulating valve for adjusting the amount of water supplied from the external water supply means to the mixing unit, and the control device supplies the external water at predetermined intervals. By controlling the operation of the external water regulating valve so that water is supplied from the means to the mixing section, the pH of the mixed waste water can be more effectively set within a predetermined range.

  Further, in the fuel cell cogeneration system of the present invention, the water supply means for mixing is provided in the circulating pipe, a circulating water supply pipe connecting the circulating pipe and the mixing unit, and the circulating water supply pipe, A circulating water adjustment valve for adjusting a supply amount of water supplied from the circulation pipe to the mixing unit, and the control device supplies the circulating water flowing through the circulation pipe at predetermined intervals. It is preferable to control the operation of the circulating water regulating valve so as to supply to

  In such a fuel cell cogeneration system, the mixing water supply means is provided in the circulation pipe, the circulation water supply pipe connecting the circulation pipe and the mixing section, and the circulation water supply pipe. A circulating water regulating valve for regulating the amount of water to be supplied, and the operation of the circulating water regulating valve so that the controller supplies the water flowing through the circulating pipe to the mixing unit at predetermined intervals. By controlling this, the pH of the mixed waste water can be more effectively within the predetermined range.

  In the fuel cell cogeneration system of the present invention, the mixing water supply means connects the external water supply means for supplying water from the outside to the hot water storage tank, the external water supply means, and the mixing section. An external water supply pipe, an external water adjustment valve provided in the external water supply pipe for adjusting the amount of water supplied from the external water supply means to the mixing unit, the circulation pipe, and the circulation pipe A circulating water supply pipe connecting the mixing section and the circulating water supply pipe, and a circulating water adjusting valve provided in the circulating water supply pipe for adjusting the amount of water supplied from the circulation pipe to the mixing section. The hot water storage tank includes a water storage amount sensor for measuring the amount of water stored in the hot water storage tank, and a hot water storage tank temperature sensor for measuring the temperature of the water stored in the hot water storage tank, and the control device. Is Based on the values measured by the water storage amount sensor and the hot water storage tank temperature sensor, at least one of water flowing through the external water supply pipe and water flowing through the circulation pipe is supplied to the mixing section at predetermined intervals. Thus, it is preferable to control the operation of the external water regulating valve and the circulating water regulating valve.

  In such a fuel cell cogeneration system, the control device controls the operation of the external water adjustment valve and the circulating water adjustment valve at predetermined intervals based on the amount and temperature of the water stored in the hot water storage tank. Thus, water can be supplied to the mixing portion from at least one of the external water supply means and the circulation pipe, and the pH of the mixed waste water can be efficiently within a predetermined range.

  In the fuel cell cogeneration system of the present invention, the mixing water supply means connects the external water supply means for supplying water from the outside to the hot water storage tank, the external water supply means, and the mixing section. An external water supply pipe, the circulation pipe, a circulation water supply pipe that connects the circulation pipe and the mixing unit, and a three-way valve to which the external water supply pipe and the circulation water supply pipe are connected. The hot water storage tank includes a water storage amount sensor for measuring the amount of water stored in the hot water storage tank, and a hot water storage tank temperature sensor for measuring the temperature of the water stored in the hot water storage tank, and the control device. Is less of the water flowing through the external water supply pipe and the water flowing through the circulation pipe at predetermined intervals based on the values measured by the water storage amount sensor and the hot water storage tank temperature sensor. And to provide one to the mixing portion also, it is preferable to control the operation of the three-way valve.

  In such a fuel cell cogeneration system, the control device controls the operation of the three-way valve at predetermined intervals based on the amount and temperature of the water stored in the hot water storage tank, thereby providing an external water supply means and Water can be supplied to the mixing unit from at least one of the circulation pipes, the pH of the mixed waste water can be efficiently within a predetermined range, and the configuration of the fuel cell cogeneration system can be simplified. .

  In the fuel cell cogeneration system of the present invention, the circulating water supply pipe is a return pipe for supplying the hot water storage tank with water after the heat exchange in the heat exchanger. It is preferable that they are connected.

  In such a fuel cell cogeneration system, when the water flowing through the circulation pipe is supplied to the mixing section, the circulation water supply pipe supplies the water after heat exchange in the heat exchanger to the hot water storage tank. Since it is connected to the return pipe, the water flowing through the circulation pipe can be supplied to the mixing section without reducing the amount of water flowing through the heat exchanger. Thereby, the pH of the mixed waste water can be set within a predetermined range without reducing the heat exchange efficiency.

  Further, in the fuel cell cogeneration system according to the present invention, the control device discharges the raw fuel and water supplied to the reformer corresponding to the power generation amount of the fuel cell and the heat exchanger. The amount of waste water from the water tank is calculated from the temperature of the exhaust gas after heat exchange, and the pH of the mixed waste water in which waste water from the water tank and water other than waste water from the water tank are mixed is within a predetermined range. It is preferable to control the operation of the mixing water supply means so that water other than the waste water from the water tank is supplied to the mixing unit so as to be inside.

  In such a fuel cell cogeneration system, the control device has an amount of raw fuel and water supplied to the reformer corresponding to the amount of power generated by the fuel cell, and after heat exchange discharged from the heat exchanger. The amount of waste water from the water tank is calculated from the temperature of the exhaust gas of the water tank so that the pH of the mixed waste water in which the waste water from the water tank and water other than the water tank are mixed is within a predetermined range. Since the operation of the mixing water supply means is controlled so as to supply water other than the wastewater from the mixing section to the mixing section, it is possible to supply the mixing section with water other than the drainage from an appropriate amount of water tank, and to efficiently mix the drainage. The pH can be within a predetermined range.

  In the fuel cell cogeneration system of the present invention, the pH of the mixed waste water discharged to the outside is lowered by draining the mixed waste water mixed with the water other than the water tank and the waste water from the water tank to the outside. This can be suppressed, and a fuel cell cogeneration system capable of reducing the influence on the environment and sewage treatment can be obtained.

It is a block diagram which shows an example of a structure of the fuel cell cogeneration system of this invention. It is a block diagram which shows another example of a structure of the fuel cell cogeneration system of this invention. It is a block diagram which shows another example of a structure of the fuel cell cogeneration system of this invention. It is a block diagram which shows another example of a structure of the fuel cell cogeneration system of this invention. It is a block diagram which shows another example of a structure of the fuel cell cogeneration system of this invention. It is a block diagram which shows another example of a structure of the fuel cell cogeneration system of this invention.

  FIG. 1 is a configuration diagram showing an example of a fuel cell cogeneration system (hereinafter sometimes abbreviated as a cogeneration system) of the present invention. In the following drawings, the same numbers are assigned to the same members.

  The cogeneration system shown in FIG. 1 includes a power generation unit that generates power, a hot water storage unit that stores hot water after heat exchange, a circulation pipe that circulates water between these units, and a power generation unit (water tank described later). A mixing unit including a mixing tank for mixing water discharged from the power generation unit and water other than the water discharged from the power generation unit, and an external drain pipe for discharging the mixed waste water mixed in the mixing tank to the outside. It is configured.

  The power generation unit shown in FIG. 1 includes a fuel cell stack 1 formed by combining a plurality of fuel cells (not shown) (hereinafter sometimes abbreviated as cell stack), and fuel gas supplied to the cell stack 1. A heat exchanger 5 for exchanging heat with the exhaust gas from the cell stack 1 and water, and heat exchange in the heat exchanger 5 as water to be supplied to the reformer 4 A condensed water treatment device 16 for temporarily storing and purifying the generated condensed water and a water tank 7 for storing condensed water (pure water) purified by the condensed water treatment device 16 are provided. ing. First, each member constituting the power generation unit will be described.

  The power generation unit includes a raw fuel supply device 2 for supplying a raw fuel such as natural gas, an oxygen-containing gas supply device 3 for supplying an oxygen-containing gas to the fuel cells constituting the cell stack 1, and water vapor from the raw fuel and water vapor. A reformer 4 for reforming is provided. Note that the reformer 4 vaporizes water (pure water, which may be abbreviated as appropriate hereinafter) supplied by a water pump 6 described later, and converts the raw fuel and steam supplied from the raw fuel supply device 2. A vaporizing section for mixing and a reforming catalyst for generating a fuel gas (hydrogen-containing gas) by reacting the mixed raw fuel and water vapor are provided.

  In addition, the fuel cell module which comprises a power generation unit is comprised by accommodating the cell stack 1 and the reformer 4 in a storage container. In FIG. 1, each device constituting the fuel cell module is surrounded by a two-dot chain line (indicated by M in FIG. 1).

  Also, a heat exchanger 5 for exchanging heat between the exhaust gas from the cell stack 1 and water, and a circulation pipe for circulating water for heat exchange with the exhaust gas from the cell stack 1 in the heat exchanger 5 The condensed water processing device 16 for temporarily storing condensed water generated by heat exchange in the heat exchanger 5 and purifying the condensed water (to make pure water), the heat exchanger 5 and the condensed water A condensed water supply pipe 15 connecting the treatment apparatus 16, a tank connecting pipe 17 connecting the condensed water treatment apparatus 16 and the water tank 7, and a reforming water supply pipe 24 connecting the water tank 7 and the reformer 4; The condensed water generated in the heat exchanger 5 is processed into pure water by the condensed water treatment device 16, and then stored in the water tank 7 and provided in the reforming water supply pipe 24. The water pump 6 supplies the reformer 4 (vaporizer, not shown). In the cogeneration system shown in FIG. 1, the condensate treatment device 16 corresponds to a water tank for storing condensed water generated by heat exchange in the heat exchanger 5, and in the following description, there is a special notice. Unless there is, it demonstrates using the condensed water processing apparatus 16 as a water tank for storing condensed water.

  Further, the power generation unit shown in FIG. 1 converts the DC power generated by the cell stack 1 into AC power, and adjusts the supply amount of the converted current to the external load (power conditioner). 8) Circulation pipe temperature for measuring the temperature of water supplied to the heat exchanger 5 and provided in a circulation pipe (feed pipe 12) for supplying water in the hot water storage tank 14 to be described later to the heat exchanger 5. In addition to the sensor 10, a control device 9 is provided. The control device 9 will be described later. Further, a feed pipe 12 and a return pipe 13 are provided for circulating water between a heat exchanger 5 to be described later and a hot water storage tank 14 to be described later (hereinafter, the feed pipe 12 and the return pipe 13 are combined together). The feed pipe 12 is provided with a circulation pump 11 for circulating water between the heat exchanger 5 and the hot water storage tank 14. The circulation pump 11 can also be disposed on the hot water storage unit side. And by storing each device constituting these power generation units in an exterior case, a power generation unit (fuel cell device) that can be easily installed and carried can be obtained (not shown).

  In addition, between the cell stack 1 and the heat exchanger 5, the exhaust gas processing apparatus for processing the exhaust gas which arises with the driving | operation of a fuel cell (cell stack 1) is provided (not shown). In addition, the exhaust gas treatment apparatus accommodates an exhaust gas treatment member in a storage container, and a generally known combustion catalyst can be used as the exhaust gas treatment member.

  The hot water storage unit includes a hot water storage tank 14 for storing hot water after heat exchange. The hot water storage tank 14 is connected with a hot water storage tank water supply pipe 23 for supplying water (such as tap water) from the outside. In order to reduce the pressure in the hot water storage tank 14, A hot water storage tank drain valve 25 for draining water is provided. In addition, the arrow in a figure shows the flow direction of raw fuel, oxygen-containing gas, and water.

  The condensed water treatment device 16, the water tank 7, and the hot water storage tank 14 have a condensed water drain pipe 20, water for draining water from each device when the water stored in each device overflows. A tank drain pipe 19 and a hot water storage tank drain pipe 18 are provided, and each drain pipe is connected to a mixing section (mixing tank 21) described later. The hot water tank drain valve 25 is provided in the hot water tank drain pipe 18.

  Hereinafter, a method for operating the cogeneration system shown in FIG. 1 will be described.

  In performing steam reforming to generate fuel gas used for power generation of a fuel cell, water used in the reformer 4 is accompanied by operation of the fuel cell (cell stack 1) in the heat exchanger 5. The condensed water produced | generated by the heat exchange with the waste gas produced | generated and the water which flows through a circulation piping is used. The condensed water generated in the heat exchanger 5 flows through the condensed water supply pipe 15 and is supplied to the condensed water treatment device 16. The condensed water is temporarily stored in the condensed water treatment device 16 and processed to produce pure water. The pure water generated by the condensed water treatment device 16 is supplied to the water tank 7. The water stored in the water tank 7 is supplied to the reformer 4 by the water pump 6, subjected to steam reforming with the raw fuel supplied from the raw fuel supply device 2, and the generated fuel gas is used as the fuel cell. Supplied to the cell. In the fuel battery cell, power generation is performed using the fuel gas and the oxygen-containing gas supplied from the oxygen-containing gas supply device 3. Thus, water self-sustained operation can be performed by using condensed water effectively. At this time, the water (condensed water) overflowed in the condensed water treatment device 16 is drained from the condensed water drain pipe 20, and the water overflowed in the water tank 7 is drained from the water tank drain pipe 19.

  On the other hand, the circulating water that is connected to the hot water storage tank 14 and flows through the feed pipe 12 from the hot water storage tank 14 toward the heat exchanger 5 by the circulation pump 11 is exhausted from the cell stack 1 while flowing in the heat exchanger 5. Heat exchange occurs and the temperature rises. The heated water (hot water) after the heat exchange flows through the return pipe 13 and is stored in the hot water storage tank 14. Although not shown, an outlet water temperature sensor for measuring the temperature of water after heat exchange in the heat exchanger 5 is preferably provided on the outlet side of the heat exchanger 5 in the return pipe 13. The operation of the circulation pump 11 is controlled by the control device 9 based on the temperature information of the circulating water after the heat exchange measured by the outlet water temperature sensor 10.

  Further, in the hot water storage tank 14, the hot water supply water from the hot water storage tank 23 is supplied from the outside based on the amount of hot water used by the user (the amount of water stored in the hot water storage tank 14) and the temperature of the water stored in the hot water storage tank 14. Water (such as tap water) is supplied into the hot water storage tank 14.

  On the other hand, when the hot water storage tank 14 overflows or when the internal pressure of the hot water storage tank 14 is reduced, the hot water storage tank drain valve 25 is operated to drain the water stored in the hot water storage tank 14 from the hot water storage tank drain pipe 18. To do.

  By the way, the exhaust gas discharged from the power generation unit (cell stack 1) may contain components such as carbon dioxide. Here, when a component such as carbon dioxide is dissolved in the condensed water generated by heat exchange with the water flowing through the circulation pipe in the heat exchanger 5, the quality of the condensed water (especially pH) deteriorates, When such condensed water having deteriorated water quality is drained to the outside through the condensed water drain pipe 20, there is a concern about the influence on the environment and the influence on the sewage treatment.

  Here, in order to treat the condensed water having deteriorated water quality, various devices and various treatment agents can be further provided. In this case, however, there is a problem that the cost of the cogeneration system is increased.

  Therefore, in the cogeneration system of the present invention, the drainage from the condensed water treatment device (corresponding to a water tank that temporarily stores the condensed water) that temporarily stores condensed water is used except for the drainage from the condensed water treatment device 16. After mixing with water, the mixing unit provided with the mixing tank 21 for draining outside the cogeneration system, and for supplying water other than the drainage from the condensed water treatment device 16 to the mixing unit (mixing tank 21) The mixing water supply means is provided, and the mixed waste water mixed in the mixing section is discharged to the outside of the cogeneration system via the external drain pipe 22. In addition, in the cogeneration system shown in FIG. 1, in addition to the condensed water drained from the condensed water treatment device 16, the water drained from the water tank 7 is mixed. There is a case of drainage.

  Here, in the cogeneration system shown in FIG. 1, as a mixing water supply means for supplying water other than the water discharged from the power generation unit to the mixing unit (mixing tank 21), The hot water storage tank drain pipe 18 is connected to the hot water storage tank drain pipe 18 and the hot water storage tank drain valve 25 is used to drain the water stored in the hot water storage tank 14 to the mixing section.

  That is, in the cogeneration system shown in FIG. 1, the condensed water drain pipe 20, the water tank drain pipe 19, and the hot water storage tank drain pipe 18 are respectively connected to the mixing section (mixing tank 21). The water drained from each drain pipe is mixed and then drained to the outside of the cogeneration system via the external drain pipe 22.

  Thereby, even when the pH of the water drained from the condensate treatment device 16 (condensate drain pipe 20) is low, by mixing with the drainage from the hot water storage tank 14 (hot water tank drain pipe 18), the external It can suppress that the pH of the water discharged | emitted by this falls. Thereby, it can be set as the cogeneration system which can reduce the influence which acts on an environment or a sewage treatment, and can aim at reduction of cost.

  In the cogeneration system of the present invention, when the water quality of the condensed water generated in the heat exchanger 5 is a water quality (pH) level that does not cause a problem in supplying the reformer 4, the condensed water treatment device 16. In this case, the water tank 7 corresponds to the water tank for storing the condensed water. In this case, the water drained from the water tank drain pipe 19 and the water drained from the hot water tank drain pipe 18 are mixed in the mixing section (mixing tank 21) and then passed through the external drain pipe 22. What is necessary is just to drain.

  By the way, when measuring the pH of the water drained to the outside through the external drain pipe 22, for example, a pH sensor or the like may be provided in the mixing unit (mixing tank 21). In this case, the cost of the cogeneration system is low. May rise.

  Therefore, in the cogeneration system of the present invention, the control device 9 performs mixing so that water other than waste water from the water tank (condensate treatment device 16) is supplied to the mixing unit (mixing tank 21) at predetermined intervals. The operation of the water supply means (in the cogeneration system shown in FIG. 1, the hot water tank drain valve 25) is controlled.

  Thereby, since the water in the hot water storage tank 14 is regularly supplied to the mixing unit (mixing tank 21), it is possible to efficiently suppress the pH of the water discharged to the outside from being lowered, and the pH. Since there is no need to provide a sensor, an increase in cost can be suppressed. Therefore, a fuel cell cogeneration system capable of reducing the influence on the environment and sewage treatment can be provided.

  Here, it is preferable to investigate the pH of the water drained from the condensed water treatment device 16 (condensate drain pipe 20) or the water tank 7 (water tank drain pipe 19) by operating a cogeneration system in advance. Thereby, it is possible to recognize the pH range of water drained from the condensed water treatment device 16 (condensate drain pipe 20) or the water tank 7 (water tank drain pipe 19).

  Further, the amount of water drained per unit time from the condensate treatment device 16 (condensate drain pipe 20) or the water tank 7 (water tank drain pipe 19) (drainage amount, excess condensate amount) is a fuel cell (cell It can be obtained from the amount of raw fuel and water supplied to the reformer 4 for generating the fuel gas necessary for the power generation amount of the stack 1), and the temperature of the exhaust gas after heat exchange in the heat exchanger 5. it can. In the heat exchanger 5, when setting the temperature of the exhaust gas after heat exchange in relation to the temperature of the water flowing through the circulation pipe measured by the circulation pipe temperature sensor 10 provided in the feed pipe 12, The temperature of water flowing through the circulation pipe measured by the circulation pipe temperature sensor 10 may be used, or a temperature sensor may be provided at the exhaust gas outlet after the heat exchange of the heat exchanger 5.

  Specifically, for example, from the amount of raw fuel and water (water for steam reforming) supplied to the reformer 4 in accordance with the amount of power generated by the fuel battery cell (cell stack 1), the cell stack 1 The amount of water in the exhaust gas discharged is calculated. Subsequently, the temperature of the exhaust gas after heat exchange in the heat exchanger 5 is obtained. The heat exchanger 5 is configured such that the temperature of the exhaust gas after heat exchange is set in relation to the temperature of the water flowing through the circulation pipe measured by the circulation pipe temperature sensor 10 provided in the feed pipe 12. If so, the temperature of the exhaust gas after heat exchange is calculated based on the temperature of the water flowing through the circulation pipe measured by the circulation pipe temperature sensor 10. From the amount of water contained in the exhaust gas discharged from the cell stack 1, the amount of saturated water vapor at the temperature of the exhaust gas after heat exchange is calculated, and the amount of condensed water produced per unit time is calculated. As a result, per unit time supplied by the water pump 6 for the steam reforming reaction in the reformer 4 in generating the fuel gas necessary for obtaining the power generation amount of the fuel battery cell (cell stack 1). By subtracting the amount of water, the amount of excess condensed water (drainage) can be determined.

  Thereby, the control device 9 uses the calculated amount of excess condensed water (drainage amount) and the pH of the condensed water measured in advance, and the amount of water (condensed water) necessary to bring the pH of the mixed wastewater within a predetermined range. The operation of the mixing water supply means (in the cogeneration system shown in FIG. 1, the hot water storage tank drain valve 25) is performed so that water other than the water drained from the processing device 16 is supplied to the mixing unit (mixing tank 21). Control. Thereby, when the pH of the mixed waste water is within a predetermined range, an appropriate amount of water can be supplied to the mixing unit (mixing tank 21), and the pH of the mixed waste water can be efficiently within the predetermined range. . In addition, the predetermined range of pH of the mixed waste water can be set to, for example, pH 5.8 to 8.6 which is a representative value of the waste water standard set in each region, and the following is the consent.

  In addition, when the control device 9 operates the mixing water supply means at predetermined time intervals, the predetermined time can be appropriately set based on the power generation amount of the cell stack 1, the capacity of the mixing portion (mixing tank 21), and the like. For example, it can be set between 1 minute and 120 minutes.

  Specifically, for example, in the heat exchanger 5, the temperature of the exhaust gas after heat exchange is 5 ° C. higher than the temperature of water flowing through the circulation pipe measured by the circulation pipe temperature sensor 10 provided in the feed pipe 12. In the case where the temperature is configured, the power generation amount of the cell stack 1 is 700 w, and the temperature of the water supplied to the heat exchanger 5 measured by the circulation pipe temperature sensor 10 is 5 ° C. (after heat exchange) In the case where the temperature of the exhaust gas is equivalent to 10 ° C.), the surplus condensed water amount is 4.2 g / mL. Here, when the control device 9 operates the mixing water supply means every 30 minutes, 4.2 g · mL × 30 minutes = 126 g of excess condensed water is generated. When the pH of the condensed water is 4.3, when the pH is set to 5.8 or higher, when the pH of the water supplied from the mixing water supply means is 6.6, the control device 9 is 4 The operation of the mixing water supply means may be controlled so that 6 L or more of water is supplied to the mixing section (mixing tank 21). It is preferable that the controller 9 controls the mixing water supply means to stop after supplying a necessary amount of water to the mixing section (mixing tank 21).

  In addition, based on the performance of the heat exchanger 5, the reforming performance in the reformer 4, and the like, the amount of surplus condensed water generated and pH, and the pH supplied from the mixing water supply means are appropriately different. The control device 9 may be set to appropriately control the operation of the mixing water supply means in accordance with the performance and water quality.

  FIG. 2 is a configuration diagram showing another example of the cogeneration system of the present invention. In the cogeneration system shown in FIG. 2, the case where the water from the outside is supplied as water other than the waste water from the water tank (condensate treatment apparatus 16) supplied to the mixing part (mixing tank 21) is shown.

  As described above, the exhaust gas discharged from the power generation unit (cell stack 1) may contain components such as carbon dioxide, and condensation generated by heat exchange with water flowing through the circulation pipe in the heat exchanger 5 When components such as carbon dioxide are dissolved in water, the pH of the condensed water is lowered, and when condensed water having such a lowered pH is drained to the outside through the condensed water drain pipe 20, There are concerns about the impact on sewage treatment.

  Here, in order to supply the water discharged from the hot water storage tank 14 to the mixing tank 21 through the hot water storage tank drain pipe 18, it may be necessary to provide a water meter or other sensor in the hot water storage tank drain pipe 18. Even in this case, the cost of the cogeneration system may increase. Furthermore, since the water (hot water) with the increased temperature stored in the hot water storage tank 14 is actively drained, the overall efficiency of the cogeneration system may be reduced.

  Therefore, in the cogeneration system shown in FIG. 2, the mixing water supply means connects the external water supply means for supplying water to the hot water storage tank 14 from the outside, and the external water supply connecting the external water supply means and the mixing tank 21. A pipe 26 and an external water adjustment valve 27 provided in the external water supply pipe 26 for adjusting the amount of water supplied from the external water supply means to the mixing tank 21, and at predetermined intervals. A control device 9 is provided for controlling the operation of the external water regulating valve 27 so as to supply water from the outside to the mixing unit (mixing tank 21). An external water supply pipe 26 and a hot water tank water supply pipe 23 are connected.

  Thereby, by supplying water from the outside through the external water supply pipe 26 to the mixing tank 21, the pH of the mixed waste water can be set within a predetermined range. Therefore, it is possible to suppress the pH of water (mixed wastewater) drained from the mixing tank 21 through the external drain pipe 22 from being lowered, and to reduce the influence on the environment and sewage treatment. A cogeneration system.

  As shown in FIG. 2, waste water from the hot water storage tank 14 can also be supplied to the mixing tank 21, and in this case, the control device 9 considers the waste water from the hot water storage tank 14 and supplies external water. It is preferable to control the operation of the regulating valve 27.

  Specifically, the control device 9 controls the operation of the external water regulating valve 27 every predetermined time so that external water is supplied from the external water supply pipe 26 to the mixing tank 21. Thereby, the waste water from the condensed water treatment device 16 and the external water supplied from the external water supply pipe 26 are mixed, so that the pH of the mixed waste water can be set within a predetermined range. In addition, after the pH of the mixed waste water falls within a predetermined range, the control device 9 appropriately sets the external water adjustment valve 27 so as to stop the external water supplied from the external water supply pipe 26 to the mixing tank 21. It can suppress that the usage-amount of external water increases by controlling to stop. The predetermined time for controlling the operation of the external water regulating valve 27 every predetermined time can be the time described above.

  FIG. 3 is a block diagram showing still another example of the cogeneration system of the present invention. In the cogeneration system shown in FIG. 3, a case where a circulation pipe is used as a mixing water supply means for supplying water other than the waste water from the water tank (condensate treatment device 16) to the mixing section (mixing tank 21). Show.

  In the cogeneration system shown in FIG. 3, the mixing water supply means is provided in the circulating water supply pipe 28 connecting the circulation pipe and the mixing tank 21 and the circulating water supply pipe 28, and supplies the mixing tank 21 from the circulation pipe. And a circulating water regulating valve 29 for regulating the amount of water supplied, and the circulating water regulating valve 29 is configured to supply water flowing through the circulation pipe to the mixing unit (mixing tank 21) at predetermined time intervals. A control device 9 for controlling the operation is provided.

  Thereby, by supplying water from the outside through the external water supply pipe 26 to the mixing tank 21, the pH of the mixed waste water can be set within a predetermined range. Therefore, it is possible to suppress the pH of water (mixed wastewater) drained from the mixing tank 21 through the external drain pipe 22 from being lowered, and to reduce the influence on the environment and sewage treatment. A cogeneration system.

  As shown in FIG. 3, waste water from the hot water storage tank 14 can also be supplied to the mixing tank 21, and in this case, the control device 9 considers the waste water from the hot water storage tank 14 to circulate water. It is preferable to control the operation of the regulating valve 29.

  Specifically, the control device 9 controls the operation of the circulating water adjustment valve 29 every predetermined time so that the circulating water is supplied from the circulating water supply pipe 28 to the mixing tank 21. Thereby, the waste water from the condensate treatment apparatus 16 and the circulating water supplied from the circulating water supply pipe 28 are mixed, so that the pH of the mixed waste water can be within a predetermined range. In addition, after the pH of the mixed waste water falls within a predetermined range, the control device 9 appropriately sets the circulating water adjustment valve 29 so as to stop the circulating water supplied from the circulating water supply pipe 28 to the mixing tank 21. By controlling, it can suppress that the usage-amount of circulating water increases. It should be noted that the predetermined time for controlling the operation of the circulating water regulating valve 29 every predetermined time can be the time described above.

  In addition, it is preferable that the circulating water supply pipe 28 is connected to the return pipe 13 for supplying the hot water tank 14 with water after heat exchange in the heat exchanger 5 among the circulating pipes.

  When the circulating water supply pipe 28 is connected so that the water flowing through the feed pipe 12 from the hot water storage tank 14 toward the heat exchanger 5 is supplied to the mixing tank 21, the amount of water flowing through the heat exchanger 5 is reduced. However, the heat exchange efficiency in the heat exchanger 5 may be reduced, and the amount of condensed water generated by the heat exchange in the heat exchanger 5 may be reduced.

  Here, the circulating water supply pipe 28 is connected to a return pipe 13 for supplying the hot-water tank 14 with water after heat exchange in the heat exchanger 5, whereby water flowing in the heat exchanger 5 is A decrease in the amount can be suppressed, and a decrease in heat exchange efficiency in the heat exchanger 5 and a decrease in the amount of condensed water generated by heat exchange in the heat exchanger 5 can be suppressed.

  As a result, the pH of the mixed waste water can be kept within a predetermined range without lowering the heat exchange efficiency, and a fuel cell cogeneration system capable of reducing the influence on the environment and sewage treatment. Can do.

  FIG. 4 is a configuration diagram showing still another example of the cogeneration system of the present invention. In the cogeneration system shown in FIG. 4, an example is shown in which both water from the outside and water flowing through a circulation pipe are used as water supplied to the mixing tank 21.

  In the cogeneration system shown in FIG. 2, an example of supplying water from the outside as water supplied to the mixing tank 21 is shown. In the cogeneration system shown in FIG. 3, circulation as water supplied to the mixing tank 21 is shown. Although the example in the case of supplying the water which flows through piping was shown, depending on the quantity and temperature of the water currently stored in the hot water storage tank 14, it is preferable to use these properly.

  In particular, when the amount of water stored in the hot water storage tank 14 is small, it is preferable to supply more water to the hot water storage tank 14 than the hot water storage tank water supply pipe 23. In this case, the external water supply pipe 26 It is preferable to stop the supply to the mixing tank 21 and supply the circulating water to the mixing tank 21 from the circulating water supply pipe 28.

  On the other hand, when the temperature of the water stored in the hot water storage tank 14 is low, it is preferable to stop the external water supplied to the hot water storage tank 14 from the hot water storage tank water supply pipe 23. It is preferable to stop the supply to the mixing tank 21 from the water supply pipe 28 and supply the external water to the mixing tank 21 from the external water supply pipe 26.

  Therefore, the cogeneration system shown in FIG. 4 shows an example in which both water from the outside and water flowing through the circulation pipe are used as the water supplied to the mixing tank 21.

  Specifically, the mixing water supply means includes an external water supply means for supplying water to the hot water storage tank 14 from the outside, an external water supply pipe 26 connecting the external water supply means and the mixing tank 21, and an external water supply. An external water adjustment valve 27 provided in the supply pipe 26 for adjusting the amount of water supplied from the external water supply means to the mixing tank 21, a circulation pipe, a circulation pipe (return pipe 13), and the mixing tank 21 A circulating water supply pipe 28 to be connected and a circulating water adjustment valve 29 provided in the circulating water supply pipe 28 for adjusting the amount of water supplied from the circulation pipe to the mixing tank 21 are included. Further, the hot water storage tank 14 is provided with a water storage amount sensor 31 for measuring the amount of water stored in the hot water storage tank 14 and a hot water storage tank temperature sensor 32 for measuring the temperature of the water stored in the hot water storage tank 14. On the basis of information measured by the water storage amount sensor 31 and the hot water storage tank temperature sensor 32, at least one of water flowing through the external water supply pipe 26 and water flowing through the circulation pipe is supplied to the mixing tank 21 at predetermined intervals. Thus, the control device 9 that controls the operation of the external water adjustment valve 27 and the circulating water adjustment valve 29 is provided.

  Thereby, based on the amount of water stored in the hot water storage tank 14 measured by the water storage amount sensor 31 and the temperature of the water stored in the hot water storage tank 14 measured by the hot water storage tank temperature sensor 32, the control device 9 makes the predetermined intervals. Further, by controlling the operations of the external water regulating valve 27 and the circulating water regulating valve 29 and appropriately supplying water from the external water supply pipe 26 and the circulating water supply pipe 28 to the mixing tank 21, the pH of the mixed waste water can be efficiently obtained. Can be within a predetermined range.

  Specifically, the storage water amount information of the hot water storage tank 14 measured by the water storage amount sensor 31 and the temperature information of the water stored in the hot water storage tank 14 measured by the hot water storage tank temperature sensor 32 are transmitted to the control device 9. The The control device 9 controls the operation of the external water adjustment valve 27 and the circulating water adjustment valve 29 at predetermined intervals, and supplies water to the mixing tank 21 from the external water supply pipe 26 and the circulating water supply pipe 28 as appropriate. In this case, when the stored water amount information transmitted from the stored water amount sensor 31 is outside the predetermined range, the external water regulating valve 27 and the circulating water are supplied to the mixing tank 21 from the circulating water supply pipe 28. The operation of the circulating water adjustment valve 29 is controlled. Thereby, the condensed water treatment apparatus 16 and the circulating water supplied from the circulating water supply pipe 28 are mixed, whereby the pH of the mixed waste water can be set within a predetermined range. Here, the predetermined range of the water storage amount can be appropriately set based on the capacity of the hot water storage tank 14 and the like, for example, the minimum water storage amount.

  On the other hand, the control device 9 controls the operation of the external water regulating valve 27 and the circulating water regulating valve 29 every predetermined time, and supplies water to the mixing tank 21 from the external water supply pipe 26 and the circulating water supply pipe 28 as appropriate. However, at that time, when the temperature information transmitted from the hot water storage tank temperature sensor 32 is out of the predetermined range, the external water regulating valve is arranged so that the external water is supplied from the external water supply pipe 26 to the mixing tank 21. 27 and the operation of the circulating water regulating valve 29 are controlled. Thereby, the waste water from the condensate treatment apparatus 16 and the external water supplied from the external water supply pipe 26 are mixed, so that the pH of the mixed waste water can be within a predetermined range. Here, the predetermined range of the temperature of the water stored in the hot water storage tank 14 can be set as appropriate. For example, the temperature of the water on the bottom side of the hot water storage tank 14 can be set to 65 ° C to 80 ° C. The control device 9 controls the operations of the external water adjustment valve 27 and the circulating water adjustment valve 29 so that water is supplied to the mixing tank 21 from both the external water supply pipe 26 and the circulating water supply pipe 28. You can also. The predetermined time for controlling the operation of the external water regulating valve 27 and the circulating water regulating valve 29 every predetermined time can be the time described above.

  FIG. 5 is a configuration diagram showing still another example of the cogeneration system of the present invention. In the cogeneration system shown in FIG. 5, the example in the case of using both the water from the outside and the water flowing through the circulation pipe is shown as the water supplied to the mixing tank 21, and is compared with the cogeneration system shown in FIG. An external water supply pipe 26 that connects the external water supply means and the mixing tank 21 and a circulating water supply pipe 28 that connects the circulation pipe and the mixing tank 21 are connected by a three-way valve 33. And the mixing tank 21 are connected by a connecting pipe 30, the external water regulating valve 27 and the circulating water regulating valve 29 are not provided, and the control device 9 includes a water storage amount sensor 31 and a hot water storage tank temperature sensor. The difference is that the operation of the three-way valve 33 is controlled based on the information measured by 32.

  In the cogeneration system shown in FIG. 5, the control device 9 controls the operation of the three-way valve 33 based on information measured by the water storage amount sensor 31 and the hot water storage tank temperature sensor 32, so that the external water supply pipe 26 or By supplying water to the mixing tank 21 from the circulating water supply pipe 28, the pH of the mixed waste water can be efficiently within a predetermined range.

  Specifically, the storage water amount information of the hot water storage tank 14 measured by the water storage amount sensor 31 and the temperature information of the water stored in the hot water storage tank 14 measured by the hot water storage tank temperature sensor 32 are transmitted to the control device 9. The The control device 9 controls the operation of the three-way valve 33 at predetermined intervals to supply water to the mixing tank 21 from the external water supply pipe 26 and the circulating water supply pipe 28 as appropriate. When the stored water amount information transmitted is outside the predetermined range, the operation of the three-way valve 33 is controlled so that the circulating water is supplied from the circulating water supply pipe 28 to the mixing tank 21. Thereby, the waste water from the condensate treatment apparatus 16 and the circulating water supplied from the circulating water supply pipe 28 are mixed, so that the pH of the mixed waste water can be within a predetermined range. Here, the predetermined range of the water storage amount can be appropriately set based on the capacity of the hot water storage tank 14 and the like, for example, the minimum water storage amount.

  On the other hand, the control device 9 controls the operation of the three-way valve 33 to supply water to the mixing tank 21 from the external water supply pipe 26 and the circulating water supply pipe 28 as appropriate. When the temperature information is outside the predetermined range, the operation of the three-way valve 33 is controlled so that external water is supplied from the external water supply pipe 26 to the mixing tank 21. Thereby, the waste water from the condensate treatment apparatus 16 and the external water supplied from the external water supply pipe 26 are mixed, so that the pH of the mixed waste water can be within a predetermined range. Here, the predetermined range of the temperature of the water stored in the hot water storage tank 14 can be set such that the temperature of the water on the bottom side of the hot water storage tank 14 is 65 ° C. to 80 ° C., for example. In addition, the predetermined time for controlling the operation of the three-way valve 33 every predetermined time can be the time described above.

  FIG. 6 is a configuration diagram showing still another example of the cogeneration system of the present invention. In the cogeneration system shown in FIG. 6, in addition to the cogeneration system shown in FIG. 4, water (such as tap water) supplied from the outside is purified, and the purified water is supplied to the reformer 4. An external water treatment device X is provided.

  When the outside air temperature is high and the humidity is low, the amount of condensed water generated by heat exchange in the heat exchanger 5 may be small. In this case, it may be difficult for the cogeneration system to perform water self-sustained operation. Further, even when the amount of water stored in the water tank 7 is small, there is a possibility that water self-sustained operation becomes difficult.

  Therefore, the fuel cell device shown in FIG. 6 includes an external water purification device X for purifying water supplied from the outside and supplying the purified water to the reformer 4.

  Here, as the external water purification device X, a water supply valve 35 for adjusting the amount of water supplied from the outside, an activated carbon filter device 36 for purifying water, a reverse osmosis membrane device 37, and an ion exchange resin device 38. Among these devices, at least an ion exchange resin device 38 (preferably all devices) and a water supply pipe 34 for connecting each device are provided. In FIG. 6, water supplied from the outside is purified and purified. Each device for supplying water to the reformer 4 is surrounded by a one-dot chain line, and is shown as an external water purification device X. The water purified by the ion exchange resin device 38 is supplied to the water tank 7.

  In addition, the external water purification apparatus X shall mean each apparatus for processing the water supplied from the outside mentioned above, and in the cogeneration system shown in FIG. 6, the structure provided with all the said each apparatus. Show.

  Here, external water supplied to the external water purification apparatus X can also be used as the mixing water supply means. In the cogeneration system shown in FIG. 6, the mixing water supply means is the same as that of the cogeneration system shown in FIG. In addition to the configuration, a water supply pipe 34 that supplies water to the external water purification apparatus X, a water supply valve 35 (three-way valve) provided in the water supply pipe 34, one end of the water supply valve 35, and the mixing tank 21 are connected. And a water supply pipe 39. As the water supply valve 35, a valve such as an electromagnetic valve can be provided in each of the water supply pipe 34 and the water supply pipe 39 instead of the three-way valve. In this case, the electromagnetic valve provided in the water supply pipe 34 is preferably provided on the downstream side of the connection portion with the water supply pipe 39.

  Thereby, when it is difficult to supply water to the mixing tank 21 from the external water supply pipe 26 or the circulating water supply pipe 28, the control device 9 controls the operation of the water supply valve 35 every predetermined time. The external water flowing through the water supply pipe 34 can be supplied to the mixing tank 21 via the water supply pipe 39, and the pH of the mixed waste water can be set within a predetermined range.

  Specifically, the control device 9 controls the operation of the mixing water supply means every predetermined time. At this time, the stored water amount information transmitted from the stored water amount sensor 31 is out of the predetermined range, and the hot water storage tank When the temperature information transmitted from the temperature sensor 32 is out of a predetermined range, a water supply valve (three-way valve) is provided so that external water flowing through the water supply pipe 34 is supplied to the mixing tank 21 via the water supply pipe 39. ) 35 operation is controlled. Thereby, the waste water from the condensate treatment apparatus 16 and the external water supplied via the water supply pipe 39 are mixed, so that the pH of the mixed waste water can be within a predetermined range.

  Although the present invention has been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications and improvements can be made without departing from the scope of the present invention.

  For example, in the above-described example, the mixing unit (mixing tank 21) and the external drain pipe 22 are illustrated and disposed in a portion outside the power generation unit and the hot water storage unit. However, the mixing unit (mixing tank 21) is disposed in the power generation unit. It can also be placed in a hot water storage unit.

  For example, although the example provided with the mixing tank 21 as a mixing part was shown, the mixing member for mixing the waste_water | drain from the condensed water processing apparatus 16 and the mixing water supplied from the mixing water supply means is provided, and a mixing member is provided. It is also possible to supply the mixed wastewater to the mixing tank 21 after mixing the wastewater from the condensed water treatment device 16 and the mixing water supplied from the mixing water supply means.

  Furthermore, in the cogeneration system of the present invention, the control device 9 controls the mixing water supply means every predetermined time. For example, the mixing tank 21 includes a water storage amount sensor, and the water storage amount of the mixing tank 21 that measures the water storage amount sensor is measured. It is also possible to control the mixing water supply means so that the mixing water is supplied to the mixing tank 21 every time the value exceeds a predetermined value. Thereby, while being able to make the pH of mixed waste water into the predetermined range efficiently, it can suppress that the usage-amount of mixing water increases.

  Further, in a configuration that does not include the external water purification device X, the stored water amount information transmitted from the stored water amount sensor 31 is out of the predetermined range, and the temperature information transmitted from the hot water storage tank temperature sensor 32 is out of the predetermined range. In this case, the control device 9 can also control to stop the power generation in the power generation unit. In this case, by stopping the power generation in the power generation unit, it is possible to stop the water having deteriorated water quality from being drained to the outside.

1: Fuel cell stack 5: Heat exchanger 7: Water tank 9: Controller 12: Feed pipe 13: Return pipe 14: Hot water tank 16: Condensate water treatment device 18: Hot water tank drain pipe 19: Water tank drain pipe 20 : Condensate drain pipe 21: Mixing tank 22: External drain pipe 26: External water supply pipe 27: External water adjustment valve 28: Circulating water supply pipe 29: Circulating water regulation valve 33: Three-way valve X: External water treatment device

Claims (8)

Fuel cell for generating power with fuel gas and oxygen-containing gas, reformer for generating fuel gas to be supplied to the fuel cell, heat for exchanging heat between exhaust gas and water from the fuel cell A power generation unit comprising a water tank for storing condensed water generated by heat exchange in the heat exchanger as water to be supplied to the exchanger and the reformer;
A hot water storage unit having a hot water storage tank for storing water after heat exchange;
A circulation pipe for circulating water between the heat exchanger and the hot water storage tank;
A mixing section comprising a mixing tank for mixing the drainage from the water tank and water other than the drainage from the water tank;
Mixing water supply means for supplying water other than the waste water from the water tank to the mixing unit;
An external drainage pipe for draining the mixed wastewater mixed in the mixing section to the outside;
A fuel cell cogeneration system comprising: a control device that controls the operation of the mixing water supply means so as to supply water other than the waste water from the water tank to the mixing unit at predetermined time intervals.   The mixing water supply means is provided in the hot water storage tank drain pipe for connecting the hot water storage tank and the mixing section, and the hot water storage tank drain pipe for draining the water stored in the hot water storage tank to the mixing section. A hot water storage tank drain valve, and the control device controls the operation of the hot water tank drain valve so as to supply the water stored in the hot water storage tank to the mixing unit every predetermined time. The fuel cell cogeneration system according to claim 1.   The mixing water supply means includes an external water supply means for supplying water to the hot water storage tank from the outside, an external water supply pipe connecting the external water supply means and the mixing section, and the external water supply pipe. And an external water adjustment valve for adjusting a supply amount of water supplied from the external water supply means to the mixing unit, and the control device supplies water from outside at predetermined intervals. The fuel cell cogeneration system according to claim 1, wherein the operation of the external water regulating valve is controlled so as to be supplied to the mixing unit.   The mixing water supply means is provided in the circulating pipe, the circulating water supply pipe connecting the circulating pipe and the mixing section, and the water supplied to the mixing section from the circulating pipe. A circulating water regulating valve for regulating the supply amount, and the control device operates the circulating water regulating valve to supply the circulating water flowing through the circulating pipe to the mixing unit at predetermined intervals. The fuel cell cogeneration system according to claim 1, wherein the fuel cell cogeneration system is controlled. The mixing water supply means includes an external water supply means for supplying water to the hot water storage tank from the outside, an external water supply pipe connecting the external water supply means and the mixing section, and the external water supply pipe. An external water regulating valve provided for adjusting the amount of water supplied from the external water supply means to the mixing unit, the circulation pipe, and a circulating water supply pipe connecting the circulation pipe and the mixing unit And a circulating water regulating valve for adjusting the amount of water supplied to the mixing unit from the circulation pipe, and provided in the circulating water supply pipe,
The hot water storage tank includes a water storage amount sensor for measuring the water storage amount of the hot water storage tank, and a hot water storage tank temperature sensor for measuring the temperature of water stored in the hot water storage tank,
The controller is configured to supply at least one of water flowing through the external water supply pipe and water flowing through the circulation pipe at predetermined intervals based on values measured by the water storage amount sensor and the hot water storage tank temperature sensor. 2. The fuel cell cogeneration system according to claim 1, wherein operations of the external water adjustment valve and the circulating water adjustment valve are controlled so as to be supplied to a mixing unit. The mixing water supply means includes an external water supply means for supplying water to the hot water storage tank from the outside, an external water supply pipe connecting the external water supply means and the mixing section, the circulation pipe, A circulation water supply pipe connecting the circulation pipe and the mixing unit, and a three-way valve connected to the external water supply pipe and the circulation water supply pipe,
The hot water storage tank includes a water storage amount sensor for measuring the water storage amount of the hot water storage tank, and a hot water storage tank temperature sensor for measuring the temperature of water stored in the hot water storage tank,
The controller is configured to supply at least one of water flowing through the external water supply pipe and water flowing through the circulation pipe at predetermined intervals based on values measured by the water storage amount sensor and the hot water storage tank temperature sensor. The fuel cell cogeneration system according to claim 1, wherein the operation of the three-way valve is controlled so as to be supplied to the mixing unit.   5. The circulating water supply pipe is connected to a return pipe for supplying water after heat exchange in the heat exchanger to the hot water storage tank among the circulating pipe. The fuel cell cogeneration system according to claim 6.   The control device, based on the amount of raw fuel and water supplied to the reformer corresponding to the power generation amount of the fuel battery cell, and the temperature of the exhaust gas after heat exchange discharged from the heat exchanger, The amount of drainage from the water tank is calculated, and the wastewater from the water tank is adjusted so that the pH of the mixed wastewater in which the wastewater from the water tank and water other than the water from the water tank are mixed is within a predetermined range. The fuel cell cogeneration system according to any one of claims 1 to 7, wherein the operation of the mixing water supply means is controlled so as to supply water other than water to the mixing section.