JP6638543B2 - Heated water production system - Google Patents

Description

  The present invention relates to a heated water production system that produces purified water by heating purified water obtained in a water treatment unit.

  BACKGROUND ART Purified water (pure water) obtained by a water treatment unit such as a pure water production apparatus is heated to produce heated water (for example, see Patent Documents 1 and 2 below). Many of the water treatment units for producing heated water are electric devices including a water supply pump, an electric valve, and the like. If the power supply is cut off due to a power failure, the purpose of producing heated water cannot be achieved. Since the use of heated water is very common in both industry and consumer life, there is a need for a heated water production system that can continue producing heated water even when a power outage occurs.

JP-A-63-189796 (FIG. 2) JP 2013-202581 A (FIG. 2)

  An object of the present invention is to provide a heated water production system that can continue producing heated water even when a power failure occurs.

  The present invention provides a water treatment unit, a fuel cell unit, and a first method for obtaining heated water by performing heat exchange between purified water produced by the water treatment unit and off-gas discharged from the fuel cell unit. A heat exchanger, wherein the water treatment unit includes: a water purification unit that obtains purified water from supply water; and a pump that suctions supply water and discharges the water toward the water purification unit. Utilizing electric power generated by a battery unit as drive power for the pump, the fuel cell unit reacts fuel and reformed water on a fuel cell and a catalyst to form a reformed gas supplied to the fuel cell. And a reformer for producing a heated water, wherein a part of the purified water produced by the water treatment unit is used as reformed water.

  Further, a purified water tank for storing the purified water produced by the water treatment unit, a purified water forward path for sending the purified water stored in the purified water tank to a use point, and purified water not used at the use point. And a purified water circulation line including a purified water return path for returning the purified water to the purified water tank, and the first heat exchanger preferably performs heat exchange of the purified water flowing through the purified water outward path.

  Further, a purified water tank for storing the purified water produced by the water treatment unit, a purified water forward path for sending the purified water stored in the purified water tank to a use point, and purified water not used at the use point. And a purified water circulation line including a purified water return path for returning the purified water to the purified water tank. The first heat exchanger preferably performs heat exchange of the purified water stored in the purified water tank.

  Preferably, when the purified water tank is full, the purified water is returned to the supply water side of the water treatment unit without being sent to the purified water tank.

  Further, the water purification section has a reverse osmosis membrane module for separating feed water into permeated water and first concentrated water, and obtains permeated water as purified water. It is preferable to use a part of the permeated water obtained by the membrane module as reforming water.

  The water purification unit further includes an electrodeionization stack for desalinating the permeated water to produce demineralized water and a second concentrated water, and obtaining the demineralized water as purified water. It is preferable that the unit uses the electric power generated by the fuel cell unit as driving electric power of the electrodeionization stack.

  The apparatus may further include a second heat exchanger for preheating the supply water by performing heat exchange between the supply water supplied to the water treatment unit and the off-gas after passing through the first heat exchanger. preferable.

  According to the present invention, it is possible to provide a heated water production system that can continue producing heated water even when a power failure occurs.

1 is an overall schematic diagram of a heated water production system 1 according to a first embodiment of the present invention. FIG. 2 is a detailed view of a water treatment unit 2 in the heated water production system 1. It is a whole schematic diagram of warm water production system 1A concerning a 2nd embodiment of the present invention (Drawing 1 correspondence figure).

<First embodiment>
Hereinafter, a first embodiment of a heated water production system according to the present invention will be described with reference to the drawings. FIG. 1 is an overall schematic diagram of a heated water production system 1 according to a first embodiment of the present invention. FIG. 2 is a detailed view of the water treatment unit 2 in the heated water production system 1. The present invention is a heated water production system 1 that produces heated water W3 by performing heat exchange between purified water W2 obtained in a water treatment unit 2 and off-gas G4 discharged from a fuel cell unit 4. FIG. 1 shows only a part of the configuration of the water treatment unit 2.

[Overall Configuration of Heated Water Production System 1]
In detail, as shown in FIG. 1, the heated water production system 1 of the first embodiment includes a water treatment unit 2, a fuel cell unit 4, and an off-gas line through which an off-gas G 4 discharged from the fuel cell unit 4 flows. L71, a first heat exchanger 71 that obtains heated water W3 by performing heat exchange between purified water W2 produced in water treatment unit 2 and off-gas G4 discharged from fuel cell unit 4, and heated water A system control unit 15 that controls the entire manufacturing system 1.

  The warmed water production system 1 of the first embodiment further includes a supply water tank 73 and a second heat exchanger 72 on the upstream side of the water treatment unit 2 and a three-way on the downstream side of the water treatment unit 2. The apparatus includes a valve V61, a purified water tank 65 for storing purified water W2, a purified water line L62, a return line L64, a purified water circulation line L65, a circulation pump 68, and a first heat exchanger 71.

  The supply water tank 73 stores the supply water W1. The supply water W1 stored in the supply water tank 73 is supplied to the water treatment unit 2 after being preheated in the second heat exchanger 72. The purified water W2 produced from the supply water W1 in the water treatment unit 2 is sent out to the purified water tank 65.

  As shown in FIG. 2, the water treatment unit 2 includes a purified water line L2 (desalinated water line L24) through which purified water W2 (detailed water to be described later) produced by the water treatment unit 2 flows. The downstream end of the desalinated water line L24 is connected to the three-way valve V61. The downstream end of the purified water line L2, the upstream end of the purified water line L62, and the upstream end of the return line L64 are connected to the three-way valve V61. The three-way valve V61 switches the distribution destination of the purified water W2 flowing through the purified water line L2 to the purified water line L62 or the return line L64.

  The downstream end of the purified water line L62 is connected to a purified water tank 65. The downstream end of the return line L64 is connected to the supply water tank 73.

  That is, the purified water W2 produced by the water treatment unit 2 is selectively sent to the purified water line L62 or the return line L64 by switching the three-way valve V61. The purified water W2 sent to the purified water line L62 is supplied to the purified water tank 65. The purified water W2 sent to the return line L64 is supplied to the supply water tank 73 and reused as a part of the supply water W1.

  A purified water circulation line L65 is connected to the purified water tank 65. The purified water circulation line L65 sends the purified water W2 stored in the purified water tank 65 to one or more use points 69, the purified water outgoing path L651, and the purified water W2 not used at the use point 69 to the purified water tank 65. The return purified water return path L652 is included. Various valves and the like (not shown) are provided in the purified water circulation line L65 in order to control the flow of the purified water circulation line L65.

  From another viewpoint of the purified water circulation line L65, the purified water W2 discharged from the purified water tank 65 is returned (circulated) to the purified water tank 65, and one or more use points from the annular return path. It is composed of one or more branch roads branching to 69. That is, the purified water forward path L651 includes a portion between the discharge portion from the purified water tank 65 and the branch portion (a branch portion from the annular return path to the branch path), and the branch path. The purified water return path L652 includes a portion between the branch portion and an introduction portion into the purified water tank 65.

  A circulation pump 68 and a first heat exchanger 71 are provided in the annular return path in the purified water outward path L651 in order from the upstream side. Note that the first heat exchanger 71 may be provided in a branch in the purified water outward path L651.

  The circulation pump 68 is a device that sucks the purified water W2 flowing through the purified water outward path L651 and pressure-feeds (discharges) it downstream (toward the first heat exchanger 71).

  The first heat exchanger 71 is a device that obtains heated water W3 by performing heat exchange between purified water W2 flowing through the purified water outward path L651 and off-gas G4 flowing through the off-gas line L71. The first heat exchanger 71 transfers the waste heat of the off-gas G4 discharged from the fuel cell unit 4 to the purified water W2 flowing through the purified water outward path L651. The temperature of the off-gas G4 discharged from the fuel cell unit 4 is about 300 ° C., and the temperature of the heated water W3 generated by heat exchange in the first heat exchanger 71 is the required temperature at the use point 69 ( (For example, 80 to 90 ° C.).

In other words, the purified water tank 65 is heated in the unheated purified water W2 supplied through the purified water line L62, or in the purified water forward path L651 of the purified water circulation line L65, and returned through the purified water return path L652. The purified water W2 (warmed water W3) is stored.
The “warmed water W3” refers to purified water W2 (desalinated water) heated in the first heat exchanger 71. The “purified water W2” widely refers to the purified water W2 regardless of whether or not the first heat exchanger 71 and the second heat exchanger 72 are heated. In the present embodiment, since the feed water W1 flowing through the feed water line L1 is preheated by the second heat exchanger 72, regardless of whether or not the feed water W1 is heated by the first heat exchanger 71, the temperature of the purified water W2 Is higher than room temperature. Therefore, “purified water” is not limited to room temperature water.

  The purified water tank 65 is provided with a water level sensor 66 for detecting the water level of the stored purified water W2. The water level sensor 66 is electrically connected to the system control unit 15, and the detected water level value is output to the system control unit 15 as a detection signal.

  In the warmed water production system 1 of the first embodiment, the water treatment unit 2 sucks the supply water W1 and discharges the water W1 to the water purification unit 21 for obtaining the purified water W2 from the supply water W1. It includes a pressure pump 26 and a water treatment control unit 25 for controlling the water treatment unit 2, and uses the power E <b> 1 generated by the fuel cell unit 4 as drive power for the pressure pump 26. The fuel cell unit 4 includes a fuel cell 41, a reformer 42 that reacts the fuel G1 with the reforming water W4 on the catalyst to generate a reformed gas G3 supplied to the fuel cell 41, and a fuel cell unit. And a battery control unit 45 for controlling the water purification unit 4 and uses a part of the purified water W2 produced by the water treatment unit 2 as the reformed water W4.

[Water treatment unit 2]
The details of the water treatment unit 2 will be described. As shown in FIG. 1, the water treatment unit 2 is a pure water production apparatus that produces purified water W2 (demineralized water; pure water) from supply water W1 (for example, raw water such as tap water).

  As shown in FIG. 2, the water treatment unit 2 includes a pre-filter 28, a pressurizing pump 26, an inverter 27, an RO membrane module (reverse osmosis membrane module) 22, an EDI stack (electrodeionization stack) 23, , A DC power supply device 24, and a water treatment control unit 25. The RO membrane module 22 and the EDI stack 23 constitute a water purification unit 21. Further, the inverter 27 and the DC power supply 24 are electrically connected to the water treatment control unit 25. Note that FIG. 2 shows only main connection lines among the connection lines.

  The water treatment unit 2 includes a supply water line L1, a permeated water line L21, an RO concentrated water line L23, a desalinated water line L24, and an EDI concentrated water line L25 for introducing or discharging water from the water purification unit 21. , A reforming water supply line L5. The permeated water line L21 and the desalinated water line L24 are collectively referred to as a "purified water line L2". The “line” in the present specification is a general term for lines such as a flow path, a path, and a pipe through which a fluid can flow.

  The supply water line L1 is a line that circulates the supply water W1 to the RO membrane module 22 (water purification unit 21). The upstream end of the supply water line L1 is connected to the supply water tank 73. The downstream end of the feedwater line L1 is connected to a primary inlet port (feedwater inlet) of the RO membrane module 22.

In the supply water line L1, a second heat exchanger 72, a pre-filter 28, and a pressurizing pump 26 are provided in this order from the upstream side.
The second heat exchanger 72 preheats the supply water W1 by performing heat exchange between the supply water W1 flowing through the supply water line L1 and the off-gas G4 after passing through the first heat exchanger 71 ( Details will be described later). The second heat exchanger 72 transfers the residual heat of the off-gas G4 after passing through the first heat exchanger 71 to the supply water W1 flowing through the supply water line L1. The off-gas G4 after passing through the second heat exchanger 72 is discharged out of the system. The supply water W1 heated in the second heat exchanger 72 is introduced into the water treatment unit 2.
The pre-filter 28 performs a simple filtration process on the supply water W1 before being supplied to the RO membrane module 22.

  The pressurizing pump 26 is a device that sucks the supply water W1 flowing through the supply water line L1 and pressure-feeds (discharges) it to the RO membrane module 22. The driving power whose frequency is converted is input from the inverter 27 to the pressurizing pump 26. The pressurizing pump 26 is driven at a rotation speed according to the frequency of the input driving power (hereinafter, also referred to as “driving frequency”).

  The inverter 27 is an electric circuit (or a device having the circuit) for supplying the frequency-converted driving power to the pressurizing pump 26. The inverter 27 receives a frequency setting signal from the water treatment control unit 25. The inverter 27 supplies drive power of a drive frequency corresponding to the frequency setting signal (for example, a current value signal of 4 to 20 mA or a voltage value signal of 0 to 10 V) input by the water treatment control unit 25 to the pressure pump 26. Output.

  The RO membrane module 22 separates the supply water W1 pumped by the pressurizing pump 26 into purified water W2 (permeated water) from which dissolved salts have been removed and first concentrated water W5 in which dissolved salts have been concentrated. . The RO membrane module 22 is configured by storing a single or a plurality of spiral RO membrane elements in a pressure vessel (vessel). Examples of the RO membrane used for the RO membrane element include a crosslinked aromatic polyamide-based composite membrane.

  The RO concentrated water line L23 is a line for discharging the first concentrated water W5 separated by the RO membrane module 22 to the outside of the water treatment unit 2. The upstream end of the RO concentrated water line L23 is connected to a primary-side outlet port (concentrated water outlet). The downstream end of the RO concentrated water line L23 is connected to or opened to, for example, a drainage pit (not shown).

  The permeated water line L21 is a line for flowing the purified water W2 (permeated water) separated by the RO membrane module 22 to the EDI stack 23. The upstream end of the permeate line L21 is connected to a secondary port (permeate outlet) of the RO membrane module 22. The downstream end of the permeated water line L21 is branched (the branched line is not shown), and is connected to the inlet side of the desalting chamber of the EDI stack 23 and the inlet side of the enrichment chamber, respectively. I have.

  The reformed water supply line L5 is connected to the permeated water line L21. The reformed water supply line L5 is a line that allows a part of the purified water W2 (permeated water) obtained in the water purifying section 21 to flow as reformed water W4 toward the reformer 42 (described later). The reformed water supply line L5 is provided with a two-way valve V25 and an orifice 29 in order from the permeated water line L21. The two-way valve V25 controls the supply and stop of the reforming water W4, and is controlled by an open / close command signal from the system control unit 15. The orifice 29 is a flow controller for adjusting the flow rate of the reforming water W4 flowing through the reforming water supply line L5.

  The orifice 29 preferably has a capacity coefficient (CV value) set as follows. That is, the 8-inch type RO membrane element has a capacity to produce permeated water of about 1000 L / h and the 4-inch type RO membrane element has a capacity of about 500 L / h. It is sufficient that the amount is less than 1% (for example, about 2 to 3 L / h) with respect to the total amount of the permeated water separated by the RO membrane module 22. Therefore, the capacity coefficient of the orifice 29 is set so that the flow rate of less than 1% can be secured.

  The EDI stack 23 performs a desalination treatment (deionization treatment) on the purified water W2 (permeated water) separated by the RO membrane module 22, and further purifies the purified water W2 (demineralized water) and the second concentrated water W6. And separated into The EDI stack 23 is electrically connected to the DC power supply 24. A DC voltage is applied to the EDI stack 23 from a DC power supply 24 as power for desalination. The EDI stack 23 is energized by the DC voltage applied from the DC power supply 24 and operates.

  The DC power supply 24 applies a DC voltage between a pair of electrodes of the EDI stack 23. An applied voltage setting signal is input from the water treatment control unit 25 to the DC power supply 24. The DC power supply 24 converts the DC voltage having a voltage value corresponding to the applied voltage setting signal (for example, a current value signal of 4 to 20 mA or a voltage value signal of 0 to 10 V) input by the water treatment control unit 25 into the EDI stack 23. To supply.

  In the EDI stack 23, a cation exchange membrane and an anion exchange membrane (not shown) are alternately arranged between a pair of electrodes. The inside of the EDI stack 23 is partitioned by these ion exchange membranes into a desalination room and a concentration room (including an anode room and a cathode room). The desalting chamber is filled with an ion exchanger (not shown). As the ion exchanger filled in the desalting chamber, for example, an ion exchange resin or an ion exchange fiber is used.

  One end of the downstream side of the permeated water line L21 is connected to the inlet side of the desalination chamber. A desalinated water line L24 for flowing the desalinated purified water W2 (desalinated water; pure water) is connected to the outlet side of the desalination chamber. The other end of the permeated water line L21 that is branched downstream is connected to the inlet side of the concentration chamber. On the other hand, an upstream end of an EDI concentrated water line L25 through which the second concentrated water W6 in which ions are concentrated flows is connected to the outlet side of the concentration chamber. The downstream end of the EDI concentrated water line L25 is connected or opened to, for example, a drain pit (not shown).

The water treatment unit 2 uses the electric power E1 generated by the fuel cell unit 4 as driving power for the pressurizing pump 26. Therefore, the water treatment unit 2 supplies the electric power E1 from the fuel cell unit 4 to the inverter 27 via a built-in power receiving panel (not shown). The inverter 27 converts the frequency of the supplied electric power E1 and drives the pressurizing pump 26 using the electric power.
Further, the water treatment unit 2 uses the electric power E1 generated by the fuel cell unit 4 as driving power for the EDI stack 23. Therefore, the water treatment unit 2 supplies the electric power E1 from the fuel cell unit 4 to the DC power supply device 24 via the built-in power receiving panel. The DC power supply 24 converts the supplied electric power E1 (AC power) into DC and drives the EDI stack 23 using the electric power.

[Fuel cell unit 4]
As shown in FIG. 1, the fuel cell unit 4 includes a fuel cell 41, a reformer 42, a battery control unit 45, a fuel supply line L41, an air supply line L42, a reformed gas supply line L43, A reforming water supply line L5 and an off-gas line L71 are provided.

  The fuel supply line L41 allows the raw fuel gas G1 as a fuel from a fuel supply unit (not shown) to flow to the reformer. The upstream end of the fuel supply line L41 is connected to a fuel supply unit (not shown) capable of supplying a raw fuel gas G1 such as city gas, and the downstream end of the fuel supply line L41 is It is connected to a reformer 42.

  The air supply line L42 allows the air G2 that has passed through the blower (not shown) and the air filter (not shown) to flow through the fuel cell 41. The upstream end of the air supply line L42 is connected to a blower for supplying the air G2 to the fuel cell unit 4. The downstream end of the air supply line L42 is connected to the cathode side of the fuel cell 41.

  In the reformed gas supply line L43, the reformed gas G3 containing hydrogen generated in the reformer 42 flows toward the fuel cell 41. The upstream end of the reformed gas supply line L43 is connected to the reformer 42, and the downstream end of the reformed gas supply line L43 is connected to the anode side of the fuel cell 41.

  A catalyst is housed inside the reformer 42. The reformer 42 causes the steam of the reforming water W4 supplied through the reforming water supply line L5 to react with the raw fuel gas G1 supplied through the fuel supply line L41 on the catalyst. This reaction is called a steam reforming reaction, and in the reformer 42, a reformed gas G3 (hydrogen-containing gas) is generated. The generated reformed gas G3 is supplied to the fuel cell 41 through the reformed gas supply line L43.

  In the present embodiment, the fuel cell 41 is constituted by a solid oxide fuel cell (SOFC). The solid oxide fuel cell has a cell stack structure in which a plurality of single cells are stacked. Specifically, the cell stack has a structure in which an anode (fuel electrode), a cathode (air electrode), and a ceramic single cell including an electrolyte are connected via an interconnector. In each unit cell incorporated in the cell stack, the reformed gas G3 (hydrogen-containing gas) is supplied to the anode side, and the air G2 (oxidant gas) is supplied to the cathode side, and hydrogen and oxygen are reacted inside. Power generation is performed.

  The battery control unit 45 generates electric power by controlling a group of accessories housed in the fuel cell unit 4. The accessory group is a general term for devices necessary for power generation operation, power supply, and the like. The battery control unit 45 controls the auxiliary equipment group based on the operation command signal from the system control unit 15 so that the water treatment unit 2 generates a necessary amount of electric power E1.

  The operating temperature of the cell stack of the solid oxide fuel cell during power generation is high, and the temperature reaches as high as 600 to 1000 ° C. In the cell stack during power generation, off-gas G4 is generated as a by-product of the electrical reaction, and this off-gas G4 is discharged outside the fuel cell unit 4. The temperature of the off-gas G4 discharged from the fuel cell unit 4 is about 300 ° C. The electric power E1 generated by the fuel cell 41 is sent to a power conditioner (not shown) and supplied to the water treatment unit 2 after being converted into an AC voltage or as a DC voltage without being transformed. .

  The off-gas line L71 is a line through which the off-gas G4 discharged from the fuel cell unit 4 (fuel cell 41) flows. The upstream end of the off-gas line L71 is connected to the cathode side of the fuel cell 41 and the combustor attached to the reformer. The downstream end of the off-gas line L71 is open to the atmosphere. In the off-gas line L71, a first heat exchanger 71 and a second heat exchanger 72 are provided in order from the upstream side.

  The waste heat of the off-gas G4 flowing through the off-gas line L71 is used in the first heat exchanger 71 to heat the purified water W2 flowing through the purified water outward path L651 of the purified water circulation line L65. The residual heat of the off-gas G4 after passing through the first heat exchanger 71 is used in the second heat exchanger 72 for preheating the supply water W1 flowing through the supply water line L1. The off-gas G4 that has passed through the second heat exchanger 72 is discharged out of the system because there is little heat that can be recovered.

  The fuel cell unit 4 uses the purified water W2 flowing through the reformed water supply line L5 as the reformed water W4. That is, the fuel cell unit 4 obtains steam from the purified water W2 (permeated water) obtained by the reverse osmosis membrane module 22, and uses the steam in the steam reforming reaction in the reformer 42.

[System control unit 15]
The system control unit 15 controls the entire heated water production system 1. The system control unit 15 is electrically connected to the water treatment control unit 25 of the water treatment unit 2 and the battery control unit 45 of the fuel cell unit 4. Hereinafter, the control state of the system control unit 15 will be described in detail.

(1) Operation of the fuel cell unit 4 and the water treatment unit 2 Not only solid oxide fuel cells but also various fuel cells are known to deteriorate in cell stacks when starting and stopping are repeated, resulting in reduced power generation capacity. Have been. Therefore, the system control unit 15 transmits an operation command signal to the battery control unit 45 so that the fuel cell unit 4 can continuously generate power without stopping. On the other hand, the system control unit 15 transmits an operation command signal to the water treatment control unit 25 so that the water E2 generated by the fuel cell unit 4 is continuously consumed by the water treatment unit 2. During the reception of the operation command signal, the water treatment control unit 25 drives the pressurizing pump 26 and the EDI stack 23 using the electric power E1 generated by the fuel cell unit 4. Thereby, the purified water W2 is continuously produced while the power supply from the fuel cell unit 4 and the power consumption in the water treatment unit 2 are simultaneously performed.

(2) Water supply stop mode When the detected water level value of the water level sensor 66 is higher than the upper limit set water level (water supply stop water level H) (when the purified water tank 65 is full), the system control unit 15 switches the three-way valve V61. Then, the return line L64 is selected as the distribution destination. Thereby, a water circulation line including the supply water line L1, the permeated water line L21, the desalinated water line L24, and the return line L64 is formed.

  In this control mode, the supply water W1 stored in the supply water tank 73 is supplied to the second heat exchanger 72. In the second heat exchanger 72, heated supply water W1 is generated by heat exchange between the supply water W1 and the off-gas G4. The heated supply water W1 is introduced into the water treatment unit 2 and subjected to membrane separation by the RO membrane module 22 and the EDI stack 23 to produce purified water W2 (desalinated water). The entire amount of the purified water W2 produced by the water treatment unit 2 is sent to the supply water tank 73 through the deionized water line L24 and the return line L64 without being sent to the purified water tank 65.

  The off-gas G4 supplied to the second heat exchanger 72 is in a high temperature state (about 300 ° C.) in which the first heat exchanger 71 has not recovered heat. Therefore, when there is a possibility that the temperature of the supply water W1 introduced into the water treatment unit 2 may exceed the heat-resistant temperature (for example, 40 ° C.) of the RO membrane module 22, a part of the off-gas G4 is transferred to the second heat exchanger 72. It is desirable to operate to bypass.

  In the water supply stop mode, the entire amount of the purified water W2 is heated by the waste heat of the off-gas G4 while being circulated as the supply water W1 to the primary side of the water treatment unit 2. The circulation of the purified water W2 has an effect of decreasing the salt concentration of the feed water W1 with time by dilution. The reduction in the salt concentration of the supply water W1 improves the quality of the purified water W2 (demineralized water), so that it is possible to supply high-quality purified water W2 at the start of water supply. The heating of the supply water W1 has the effect of increasing the amount of water permeation in the RO membrane module 22 and increasing the amount of ion movement in the EDI stack 23. An increase in the amount of water permeation reduces the power consumption of the pressurizing pump 26, while an increase in the amount of ion transfer reduces the power consumption of the EDI stack 23. Therefore, the surplus power E1 is effectively used as driving power for other factory equipment. It becomes possible to do.

(3) Purified water supply mode When the detected water level value of the water level sensor 66 is lower than the lower limit set water level (water supply start water level L), the system control unit 15 switches the three-way valve V61 to supply the purified water line as a distribution destination. Select L62. As a result, a water supply line including the supply water line L1, the permeated water line L21, the desalinated water line L24, and the purified water line L62 is formed.

  In this control mode, the supply water W1 stored in the supply water tank 73 is supplied to the second heat exchanger 72. In the second heat exchanger 72, heated supply water W1 is generated by heat exchange between the supply water W1 and the off-gas G4. The heated supply water W1 is introduced into the water treatment unit 2 and subjected to membrane separation by the RO membrane module 22 and the EDI stack 23, thereby producing purified water W2 (desalinated water). The entire amount of the purified water W2 produced by the water treatment unit 2 is supplied to the purified water tank 65.

  The circulation pump 68 provided in the purified water circulation line L65 is continuously driven. In the first heat exchanger 71 provided on the purified water outward path L651 to the use point 69, the purified water W2 is heated by heat exchange between the purified water W2 and the off-gas G4, and the heated water W3 (high-temperature pure water) is generated. Is done. The heated water W3 is sent to the use point 69. The purified water W2 (warmed water W3) not sent to the use point 69 is returned to the purified water tank 65 via the purified water return path L652.

  An example of the temperature control of the heating water W3 is as follows. An off-gas bypass line (not shown) for bypassing the off-gas G4 is connected to the first heat exchanger 71, and a flow control valve (eg, a proportional control valve) is provided on the line. A temperature sensor (not shown) is provided on the secondary side of the first heat exchanger 71 in the purified water outward path L651 of the purified water circulation line L65. The bypass flow rate of the off-gas G4 is controlled by the flow control valve so that the temperature detected by the temperature sensor (the temperature of the heated water W3) becomes the target temperature (that is, the flow rate of the off-gas G4 flowing through the first heat exchanger 71 is controlled). Do). If the warming water W3 is not used at the use point 69 or if the amount of the warming water W3 used is small, the temperature of the purified water W2 stored in the purified water tank 65 rises. become.

  In the heated water supply mode, the purified water W2 is heated by the waste heat of the off-gas G4, and the entire amount of the supply water W1 is heated by the residual heat of the off-gas G4. Thereby, the heated water W3 (high-temperature pure water) is continuously generated using the off-gas G4 in a high-temperature state (about 300 ° C.). As a result, waste heat of the off-gas G4 is recovered without waste, and the overall efficiency (= power generation efficiency + heat recovery efficiency) of the fuel cell unit 4 is increased. The overall efficiency achievable in the heated water supply mode is, for example, 90% or more.

(4) Continuous supply of reformed water W4 In the above-described water supply stop mode and the heated water supply mode, the system control unit 15 opens the two-way valve V25, and connects the reformed water W4 ( Permeated water) continuously. As a result, the reformer 42 continuously generates the reformed gas G3 required for power generation of the fuel cell 41.

According to the heated water production system 1 according to the first embodiment, for example, the following effects are exerted.
The heated water production system 1 according to the first embodiment includes a water treatment unit 2, a fuel cell unit 4, a purified water W2 produced by the water treatment unit 2, and an off-gas G4 discharged from the fuel cell unit 4. And a first heat exchanger 71 that obtains heated water W3 by performing heat exchange with the first heat exchanger 71. The water treatment unit 2 includes a water purification unit 21 that obtains purified water W2 from the supply water W1, and a pressure pump 26 that sucks the supply water W1 and discharges the water toward the water purification unit 21. The fuel cell unit 4 uses the electric power E1 generated in Step 4 as drive power for the pressurizing pump 26, and reacts the fuel cell 41 with the fuel G1 and the reformed water W4 on the catalyst to supply the fuel cell 41 to the fuel cell 41. And a part of the purified water W2 produced by the water treatment unit 2 is used as the reformed water W4.

  In this configuration, the water treatment unit 2 utilizes the waste heat of the off-gas G4 discharged from the fuel cell unit 4 as a heating source of the purified water W2, and uses the fuel cell unit 4 The generated electric power E1 is used. In the fuel cell unit 4, purified water W2 produced in the water treatment unit 2 is used as the reformed water W4. Therefore, the heating water W3 can be manufactured at any time during the power generation of the fuel cell 41, and even when a power failure occurs, the manufacturing of the heating water W3 is continued using the power E1 and the purified water W2 generated independently in the system. be able to.

  The heated water production system 1 according to the first embodiment sends a purified water tank 65 for storing purified water W2 produced by the water treatment unit 2 and a purified water W2 stored in the purified water tank 65 to a use point 69. And a purified water circulation line L65 comprising a purified water return path L652 for returning purified water W2 not used at the use point 69 to the purified water tank 65. The first heat exchanger 71 further includes a purified water The heat exchange of the purified water W2 flowing in the outward path L651 is performed.

  With this configuration, the heated water W3 is accumulated in the purified water tank 65 while heating and circulating the purified water W2 in the purified water circulation line L65. Therefore, the heating water W3 of a predetermined temperature can be promptly supplied to the use point 69, and it is possible to flexibly cope with an increase or decrease in the consumption of the heating water W3.

  The heated water production system 1 according to the first embodiment returns the purified water W2 to the supply water side (the supply water tank 73) of the water treatment unit 2 without sending the purified water W2 to the purified water tank 65 when the purified water tank 65 is full. .

  In this configuration, when the purified water tank 65 is full, supply to the purified water tank 65 is stopped, and the purified water W2 is returned to the supply water side. Thereby, the salt concentration of the supply water W1 decreases, and the quality of the purified water W2 improves. As a result, high-quality purified water W2 can be supplied at the time of starting water supply by reducing the purified water tank 65.

  In the first embodiment, the water purification unit 21 includes the reverse osmosis membrane module 22 that separates the supply water W1 into the permeated water and the first concentrated water W5, and obtains the permeated water as the purified water W2. In addition, the fuel cell unit 4 uses a part of the permeated water obtained by the reverse osmosis membrane module 22 as the reformed water W4.

  The water purification unit 21 may include another water purification unit (for example, the EDI stack 23 in the present embodiment) in addition to the RO membrane module 22 in order to obtain more purified water W2. However, the quality of the permeated water is sufficient as the purity of the reformed water W4. Therefore, in the present embodiment, the permeated water produced by the RO membrane module 22 is used as the reformed water W4 instead of the desalted water produced by the EDI stack 23. Therefore, power can be generated without consuming high-value-added demineralized water.

  In the first embodiment, the water purification unit 21 further includes an electrodeionization stack 23 for desalinating the permeated water to produce demineralized water and the second concentrated water W6, and uses the demineralized water as purified water W2. The water treatment unit 2 uses the electric power E1 generated by the fuel cell unit 4 as driving power for the electrodeionization stack 23.

  In this configuration, the water treatment unit 2 utilizes the waste heat of the off-gas G4 discharged from the fuel cell unit 4 as a heating source of the purified water W2, and drives the electrodeionization stack 23 in addition to the pressurizing pump 26. As the electric power, the electric power E1 generated by the fuel cell unit 4 is used. Therefore, the heated water W3 can be produced from high-purity demineralized water at any time during the power generation of the fuel cell 41.

  In the first embodiment, a heat exchange is performed between the supply water W1 supplied to the water treatment unit 2 and the off-gas G4 after passing through the first heat exchanger 71 to preheat the supply water W1. The heat exchanger 72 is further provided.

  In this configuration, the purified water W2 is heated by the waste heat of the off-gas G4, and the entire amount of the supply water W1 is heated by the residual heat of the off-gas G4. Thereby, the waste heat of the off-gas G4 is recovered without waste, and the overall efficiency of the fuel cell unit 4 is improved. Further, since the power consumption of the pressurizing pump 26 and the EDI stack 23 is reduced by heating the supply water W1, the surplus power E1 can be effectively used in other facilities.

<Second embodiment>
A second embodiment of the heated water production system according to the present invention will be described with reference to the drawings. FIG. 3 is an overall schematic diagram of a heated water production system 1A according to a second embodiment of the present invention (corresponding to FIG. 1). In the second embodiment, differences from the first embodiment will be mainly described. Therefore, a detailed description of the same (or equivalent) configuration as that of the first embodiment will be omitted. The description of the first embodiment is appropriately applied to the points that are not particularly described in the second embodiment.

  In the warmed water production system 1 of the first embodiment, the first heat exchanger 71 exchanges heat with the purified water W2 flowing through the purified water outward path L651. On the other hand, as shown in FIG. 3, in the heated water production system 1A of the second embodiment, the first heat exchanger 71A exchanges heat with the purified water W2 stored in the purified water tank 65. . The first heat exchanger 71 </ b> A in the second embodiment includes, for example, a coil-shaped heat transfer tube arranged in a storage section of the purified water tank 65.

  According to the second embodiment, effects similar to those of the first embodiment are achieved. In particular, since the first heat exchanger 71A exchanges heat with the purified water W2 stored in the purified water tank 65, the first heat exchanger 71 can be incorporated in the purified water tank 65, and thereby the first heat exchanger 71A can be used. The installation space for the heat exchanger 71 is reduced.

Hereinabove, one embodiment of the present invention has been described. However, the present invention is not limited to the embodiments described above, and can be implemented in various forms.
In the above-described embodiment, the orifice 29 is used as a flow controller for controlling the flow rate of the reforming water W4, but the present invention is not limited to this. As a device having both a flow controller and a flow path switch in place of the two-way valve V25, a needle valve or a ball valve capable of controlling the valve opening may be used.

  In the above-described embodiment, in the water supply stop mode, the purified water W2 is returned to the supply water tank 73, but is not limited thereto. The purified water W2 may be returned to the supply water line L1, for example, the supply water line L1 upstream of the second heat exchanger 72.

  In the above-described embodiment, a three-way valve is used as a configuration for switching the flow path. However, the present invention is not limited thereto, and various configurations that can achieve the same function as the three-way valve can be adopted. For example, two two-way valves can be used to achieve the same function as one three-way valve.

  Instead of the EDI stack 23, a non-regenerative mixed-bed ion exchange tower may be provided. In this case, purified water W2 (demineralized water) can be obtained by deionizing the permeated water separated by the RO membrane module at the preceding stage using an ion exchange resin bed. Further, by using the ion exchange tower, the power required for the process for obtaining the desalinated water from the permeated water can be reduced to almost zero. Note that demineralized water may be used as the reformed water W4.

  A plurality of RO membrane modules can be provided in series. That is, the permeated water obtained in the first-stage RO membrane module is used as the supply water for the second-stage RO membrane module to obtain more purified permeated water. Further, a decarbonation device may be provided between the RO membrane module 22 and the EDI stack 23 or the non-regenerative mixed-bed ion exchange tower. In that case, the branch of the reformed water supply line L5 from the permeated water line L21 is disposed between the RO membrane module 22 and the decarbonation device.

Reference Signs List 1 heated water production system 2 water treatment unit 4 fuel cell unit 21 water purification unit 22 RO membrane module (reverse osmosis membrane module)
23 EDI Stack (Electric Deionization Stack)
26 Pressurizing pump (pump)
41 Fuel cell 65 Purified water tank 71 First heat exchanger 72 Second heat exchanger E1 Electric power G1 Raw fuel gas (fuel)
G3 Reformed gas G4 Off gas L1 Supply water line L5 Reformed water supply line L43 Reformed gas supply line L62 Purified water line L64 Return line L65 Purified water circulation line L651 Purified water forward path L652 Purified water return path L71 Off gas line W1 Supply water W2 Purified water (Permeated water, demineralized water)
W3 Heated water W4 Reformed water W5 First concentrated water W6 Second concentrated water

Claims (7)

A water treatment unit;
A fuel cell unit,
A first heat exchanger that obtains heated water by performing heat exchange between purified water produced by the water treatment unit and off-gas discharged from the fuel cell unit,
The water treatment unit has a water purification unit that obtains purified water from supply water, and a pump that sucks in the supply water and discharges the water toward the water purification unit, and supplies the electric power generated by the fuel cell unit. Utilizing as drive power for the pump,
The fuel cell unit includes a fuel cell, a reformer that reacts fuel and reformed water on a catalyst to generate a reformed gas supplied to the fuel cell, and the water treatment unit includes: A heated water production system that uses part of the produced purified water as reforming water. A purified water tank for storing purified water produced by the water treatment unit,
A purified water circulation line including a purified water forward path for sending purified water stored in the purified water tank to a use point, and a purified water return path for returning purified water not used at the use point to the purified water tank. ,
The first heat exchanger performs heat exchange of purified water flowing through the purified water outward path,
The heated water production system according to claim 1. A purified water tank for storing purified water produced by the water treatment unit,
A purified water circulation line including a purified water forward path for sending purified water stored in the purified water tank to a use point, and a purified water return path for returning purified water not used at the use point to the purified water tank. ,
The first heat exchanger performs heat exchange of purified water stored in the purified water tank.
The heated water production system according to claim 1. When the purified water tank is full, return the purified water to the supply water side of the water treatment unit without sending the purified water to the purified water tank,
The heated water production system according to claim 2 or 3. The water purification unit has a reverse osmosis membrane module for separating feed water into permeated water and first concentrated water, and obtains permeated water as purified water,
The fuel cell unit uses a part of the permeated water obtained by the reverse osmosis membrane module as reformed water,
The heated water production system according to claim 1. The water purification unit further includes an electrodeionization stack for desalinating the permeated water to produce demineralized water and a second concentrated water, and obtains the demineralized water as purified water.
The water treatment unit uses power generated by the fuel cell unit as driving power for the electrodeionization stack,
The heated water production system according to claim 5. The apparatus further includes a second heat exchanger that preheats the supply water by performing heat exchange between supply water supplied to the water treatment unit and off-gas after passing through the first heat exchanger.
The heated water production system according to claim 1.

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