KR20230089433A - Fuel cell system - Google Patents

Abstract

The present invention relates to a fuel cell system. According to one embodiment of the present invention, the fuel cell system may comprise: a stack which produces electricity through an electrochemical reaction between reformed gas and air; a fuel processing device which supplies the reformed gas to the stack; a blower which supplies the air to the stack; a separator which condenses moisture contained in the reformed gas, unreacted hydrogen, or air; a water supply pipe which is branched from a water supply line through which cold water flows, is connected to the separator, and supplies cold water to the separator; a water discharge pipe which is connected to the water supply line, a drain line discharging cold water to the outside, and the separator, and through which cold water discharged from the separator flows; and a drain valve which is disposed in the water discharge pipe and supplies cold water discharged from the separator to the water supply line or the drain line. Other various embodiments are possible. According to the present invention, a separator for collecting moisture in reformed gas is disposed between a reformer and a stack, and thus, the power generation efficiency of the stack can be improved.

Description

Fuel cell system {FUEL CELL SYSTEM}

The present invention relates to a fuel cell system, and more particularly, to a fuel cell system in which the energy efficiency of the system is improved and the amount of condensate collected in the system is increased by utilizing cold water flowing through a water supply line connected to a water supply point such as a building.

A fuel cell system is a power generation system that generates electrical energy by electrochemically reacting hydrogen contained in hydrocarbon-based materials, such as methanol, ethanol, and natural gas, with oxygen.

A general fuel cell system, similar to Prior Art 1 (Korean Patent Publication No. 10-2012-0071288), a fuel processing device for converting and reforming fuel containing hydrogen atoms into hydrogen gas, and a fuel processing device A stack is provided to generate electric energy using hydrogen gas supplied therefrom. In addition, the fuel cell system may further include a heat exchanger and a cooling water pipe for cooling the stack and recovering heat, a power conversion device for converting DC power generated into AC power, and the like.

Meanwhile, the reformed gas generated in the fuel processor is supplied to the sieve stack containing a certain amount of moisture and used for power generation of the stack. However, when the moisture content of the reformed gas is excessive, there is a problem in that the electrochemical reaction between hydrogen and oxygen occurring in the stack is reduced.

On the other hand, unreacted hydrogen (anode off gas, AOG) discharged after the electrochemical reaction of hydrogen and oxygen in the stack is supplied to the burner of the body fuel processing device containing a certain amount of moisture and used for combustion of the burner. However, when the moisture contained in the unreacted hydrogen is excessive, there is a problem in that the combustion reaction of the burner is reduced.

KR 10-2012-0071288 A

An object to be solved by the present invention is to provide a fuel cell system in which the amount of condensate collected in the system is increased by improving the phase separation efficiency of a separator that collects moisture contained in gas flowing in the system.

Another object of the present invention is to provide a fuel cell system including a separator with improved phase separation efficiency without a separate cooling device.

Another object of the present invention is to provide a fuel cell system in which the power generation efficiency of the stack is improved by reducing the moisture content of the reformed gas supplied to the stack.

Another object of the present invention is to provide a fuel cell system with improved power generation efficiency of a stack by reducing the moisture content of unreacted hydrogen supplied to a fuel device.

The tasks of the present invention are not limited to the tasks mentioned above, and other tasks not mentioned will be clearly understood by those skilled in the art from the following description.

In order to achieve the above object, a fuel cell system according to an embodiment of the present invention includes a stack for generating power through an electrochemical reaction between reformed gas and air; a fuel processing device supplying the reformed gas to the stack; a blower supplying the air to the stack; A separator for condensing reformed gas, unreacted hydrogen or moisture contained in the air; a water supply pipe branched from a water supply line through which cold water flows and connected to the separator, and supplying cold water to the separator; a drain pipe connected to the water supply line, a drain line for discharging cold water to the outside, and the separator, and through which the cold water discharged from the separator flows; A drain valve disposed in the drain pipe and supplying cold water discharged from the separator to the water supply line or the drain line may be included.

The drain valve, a first drain valve connected to the water supply line and regulating the flow of cold water from the separator to the water supply line; and A second drain valve connected to the drain line and regulating the flow of cold water from the separator to the drain line may be included.

a first flowmeter disposed in the water supply line and sensing a flow rate of cold water flowing through the water supply line; and a second flowmeter disposed in the drain pipe and sensing a flow rate of cold water flowing through the drain pipe. and a control unit adjusting the drain valve based on the cold water flow rate calculated by the first flow meter and the second flow meter.

The control unit calculates the total water supply amount based on the flow rate of cold water detected by the first flow meter, calculates the discharge flow rate of the separator based on the flow rate of cold water detected by the second flow meter, and calculates the total water supply amount of the separator. When the flow rate is greater than the drain flow rate, the first drain valve may be opened and the second drain valve may be closed so that the cold water discharged from the separator flows into the water supply line.

The control unit calculates the total water supply amount based on the flow rate of cold water detected by the first flow meter, calculates the discharge flow rate of the separator based on the flow rate of cold water detected by the second flow meter, and calculates the total water supply amount of the separator. When the flow rate is less than or equal to the drain flow rate, the first drain valve may be closed and the second drain valve may be opened so that the cold water discharged from the separator flows into the drain line.

a first thermometer for sensing the temperature of the reformed gas supplied to the separator; and a second thermometer for sensing a temperature of the reformed gas supplied to the stack, wherein the control unit calculates a moisture content of the reformed gas based on a difference between temperature values sensed by the thermometers, and calculates the moisture content of the reformed gas. It is possible to adjust the opening of the second drain valve according to the moisture content of the.

The second drain valve may be a three-way valve capable of adjusting an opening.

A guide pipe connecting the drain pipe and the water supply line and guiding cold water discharged from the separator to the water supply line may be included, and the first drain valve may be disposed in the guide pipe.

It may include a water supply pump disposed in the guide pipe and forming water pressure so that cold water flowing through the guide pipe flows into the water supply line.

a first thermometer for sensing the temperature of the reformed gas supplied to the separator; a second thermometer for sensing the temperature of the reformed gas supplied to the stack; and a control unit that calculates the moisture content of the reformed gas based on the difference in temperature values detected by the thermometers and adjusts the water supply pump according to the moisture content of the reformed gas.

a first gas pipe connecting the fuel processing device and the stack and guiding the reformed gas discharged from the fuel processing device to the stack; a second gas pipe connecting the fuel processing device and the stack and guiding unreacted hydrogen discharged from the stack to the fuel processing device; It may include a third gas pipe connected to the stack and through which air discharged from the stack flows.

The separator may include: a first separator disposed in the first gas pipe and collecting condensate generated through heat exchange between reformed gas discharged from the fuel processing device and cold water supplied from the water supply pipe; a second separator disposed in the second gas pipe and collecting condensed water generated through heat exchange between unreacted hydrogen discharged from the stack and cold water supplied from the water supply pipe; and a third separator disposed in the third gas pipe and collecting condensed water generated through heat exchange between air discharged from the stack and cold water supplied from the water supply pipe.

Details of other embodiments are included in the detailed description and drawings.

According to the fuel cell system of the present invention, one or more of the following effects are provided.

First, cold water may be supplied to the separator from a water supply line supplying cold water to a water supply point such as a building, and gas flowing through the separator may be cooled by the cold water supplied to the separator, thereby improving phase separation efficiency of the separator. Accordingly, the collection amount of condensate in the system may also increase.

Second, cold water can be supplied to the separator using a water supply line generally embedded in a water supply point such as a building, and accordingly, there is no need to provide a separate cooling device for cooling gas flowing through the separator.

Third, a separator for collecting moisture in the reformed gas is disposed between the reformer and the stack, and accordingly, the moisture contained in the reformed gas is reduced, thereby improving power generation efficiency of the stack.

Fourth, a separator for collecting moisture of unreacted hydrogen is disposed between the burner and the stack, and thus the moisture contained in unreacted hydrogen is reduced, thereby improving combustion efficiency of the burner.

The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims.

1 is a schematic diagram of a configuration of a fuel processing apparatus according to an embodiment of the present invention.
2 is a configuration diagram of a fuel cell system according to an embodiment of the present invention.
3 is a system diagram showing the connection relationship between a fuel processing device, a stack, a separator, and a water supply tank according to an embodiment of the present invention.
4 is an operation diagram illustrating a preheating mode of a fuel cell system according to an embodiment of the present invention.
5 is an operation diagram illustrating a reforming mode of a fuel cell system according to an embodiment of the present invention.
6 is an operation diagram illustrating the operation of a drain valve when water is being supplied to a water supply point such as a building in a power generation mode of the fuel cell system according to an embodiment of the present invention.
7 is an operation diagram illustrating the operation of a drain valve when the amount of water supplied to a water supply point such as a building is low or absent in a power generation mode of the fuel cell system according to an embodiment of the present invention.
8 is a flowchart illustrating a control method of a fuel cell system according to an embodiment of the present invention.

Hereinafter, the present invention will be described in detail with reference to the drawings. In the drawings, in order to clearly and concisely describe the present invention, parts not related to the description are omitted, and the same reference numerals are used for the same or extremely similar parts throughout the specification.

The suffixes "module" and "unit" for the components used in the following description are simply given in consideration of ease of writing this specification, and do not themselves give a particularly important meaning or role. Accordingly, the “module” and “unit” may be used interchangeably.

In this application, terms such as "comprise" or "have" are intended to designate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, but one or more other features It should be understood that the presence or addition of numbers, steps, operations, components, parts, or combinations thereof is not precluded.

Also, in this specification, terms such as first and second may be used to describe various elements, but these elements are not limited by these terms. These terms may only be used to distinguish one element from another.

1 is a schematic diagram of a configuration of a fuel processing apparatus according to an embodiment of the present invention.

Referring to FIG. 1, the fuel processing device 10 includes a desulfurizer 110, a burner 120, a steam generator 130, a reformer 140, a first reactor 150 and/or a second reactor 160. ) may be included. The fuel processing device 10 may further include at least one mixer 111 or 112.

The desulfurizer 110 may perform a desulfurization process to remove sulfur compounds contained in fuel gas. For example, the desulfurizer 110 may have an adsorbent therein. At this time, the sulfur compound included in the fuel gas passing through the desulfurizer 110 may be adsorbed to the adsorbent.

The adsorbent may be composed of metal oxide, zeolite, activated carbon, or the like.

The desulfurizer 110 may further include a filter for removing foreign substances included in the fuel gas.

The burner 120 may supply heat to the reformer 140 to promote a reforming reaction in the reformer 140 . For example, fuel gas discharged from the desulfurizer 110 and air introduced from the outside may be mixed in the first mixer 111 and supplied to the burner 120 . At this time, the burner 120 may generate combustion heat by burning a mixed gas in which fuel gas and air are mixed. In this case, the internal temperature of the reformer 140 may be maintained at an appropriate temperature (eg, 800° C.) by heat supplied from the burner 120 .

Meanwhile, exhaust gas generated in the burner 120 by combustion of the mixed gas may be discharged to the outside of the fuel processing device 10 .

The steam generator 130 may vaporize water and discharge it as water vapor. For example, the steam generator 130 may vaporize water by absorbing heat from the exhaust gas generated by the burner 120, the first reactor 150, and/or the second reactor 160.

The steam generator 130 may be disposed adjacent to a pipe through which exhaust gas discharged from the first reactor 150, the second reactor 160, and/or the burner 120 flows.

The reformer 140 may perform a reforming process of generating hydrogen gas from fuel gas from which sulfur compounds are removed by using a catalyst. For example, fuel gas discharged from the desulfurizer 110 and steam discharged from the steam generator 130 may be mixed in the second mixer 112 and supplied to the reformer 140 . In this case, when the fuel gas supplied to the reformer 140 and the water vapor undergo a reforming reaction in the reformer 140, hydrogen gas may be generated.

The first reactor 150 may reduce carbon monoxide generated by a reforming reaction among components included in the gas discharged from the reformer 140 . For example, carbon monoxide included in gas discharged from the reformer 140 may react with water vapor inside the first reactor 150 to generate carbon dioxide and hydrogen. At this time, the internal temperature of the first reactor 150 may be lower than the internal temperature of the reformer 140 and higher than room temperature (eg, 200° C.).

The first reactor 150 may be referred to as a shift reactor.

The second reactor 160 can reduce carbon monoxide remaining among components included in the gas discharged from the first reactor 150 . For example, a selective oxidation (PROX) reaction in which carbon monoxide included in gas discharged from the first reactor 150 reacts with oxygen inside the second reactor 160 may occur.

On the other hand, in the case of the selective oxidation reaction, since a large amount of oxygen is required, additional supply of air is required, and hydrogen is diluted by the additionally supplied air, which reduces the concentration of hydrogen supplied to the stack. Therefore, in order to overcome these disadvantages, a selective methanation reaction in which carbon monoxide and hydrogen react may be utilized.

Meanwhile, gas discharged from the fuel processor 10 via the reformer 140, the first reactor 150, and/or the second reactor 160 may be referred to as a reformed gas.

The stack 20 may generate electrical energy by causing an electrochemical reaction to the reformed gas supplied from the fuel processing device 10 .

The stack 20 may be configured by stacking single cells in which an electrochemical reaction occurs.

A single cell may include a membrane electrode assembly (MEA) in which an anode and an air electrode are disposed around an electrolyte membrane, a separator, and the like. At the fuel electrode of the membrane-electrode assembly, hydrogen can be separated into hydrogen ions and electrons by a catalyst to generate electricity, and at the air electrode of the membrane-electrode assembly, hydrogen ions and electrons combine with oxygen to generate water.

The stack 20 may further include a stack heat exchanger (not shown) to dissipate heat generated during the electrochemical reaction. The stack heat exchanger may be a heat exchanger that uses water as a refrigerant. For example, the cooling water supplied to the stack heat exchanger may absorb heat generated in an electrochemical reaction process, and the cooling water whose temperature is raised by the absorbed heat exchanges the stack heat exchanger. It can be discharged to the outside of the group.

2 is a configuration diagram of a fuel cell system including a fuel processing device according to an embodiment of the present invention.

Referring to FIG. 2 , the fuel cell system 1 may include a fuel processing unit (I), a power generation unit (II), a cooling water circulation unit (III), and/or a heat recovery unit (IV).

The fuel processing unit (I) includes a fuel processing device 10, a fuel valve 30 for controlling the flow of fuel gas supplied to the fuel processing device 10, and a first blower for flowing air to the fuel processing device 10. (71) and the like.

The power generation unit (II) is discharged without reacting in the stacks 20a and 20b, the reformed gas heat exchanger 21 in which heat exchange of the reformed gas discharged from the fuel processing device 10 occurs, and the stacks 20a and 20b. AOG heat exchanger 22 where gas heat exchange occurs, a humidifier 23 which supplies moisture to the air supplied to the stacks 20a and 20b, and a second blower 72 which flows air into the stacks 20a and 20b etc. may be included. Here, the gas discharged from the stacks 20a and 20b without reacting may be referred to as anode off gas (AOG). In one embodiment of the present invention, the fuel cell system 1 is described as having two stacks 20a and 20b, but is not limited thereto.

The cooling water circulation unit (III) includes a water supply tank (13) for storing water generated in the fuel cell system (1), a water pump (38) for flowing water to the fuel processing device (10), and a fuel processing device (10). ), a water supply valve 39 for controlling the flow of water supplied to the water supply, a cooling water pump 43 for flowing water to the reformed gas heat exchanger 21, and the like.

The heat recovery unit (IV) may include a heat recovery tank 15 for storing water used for heat exchange, a hot water pump 48 for flowing water stored in the heat recovery tank 15 to the outside of the heat recovery tank 15, and the like. .

The fuel valve 30 may be disposed in the fuel supply passage 101 through which fuel gas supplied to the fuel processing device 10 flows. Corresponding to the degree of opening of the fuel valve 30, the flow rate of the fuel gas supplied to the fuel processing device 10 may be adjusted. For example, the fuel valve 30 may block the fuel supply passage 101 so that the supply of fuel gas to the fuel processing device 10 is stopped.

A first fuel flow meter 51 that detects a flow rate of fuel gas flowing in the fuel supply passage 101 may be disposed in the fuel supply passage 101 .

The first blower 71 may be connected to the first external air inlet passage 201 and the fuel side air supply passage 202 . The first blower 71 may flow air introduced from the outside through the first external air inlet passage 201 to the fuel processing device 10 through the fuel side air supply passage 202 .

Air introduced into the fuel processing device 10 through the fuel-side air supply passage 202 may be supplied to the burner 120 of the fuel processing device 10 . For example, air introduced into the fuel processor 10 may be mixed with fuel gas discharged from the desulfurizer 110 in the first mixer 111 and supplied to the burner 120 .

An air filter 91 that removes foreign substances such as dust contained in the air and/or a first air-side check valve 81 that restricts the flow direction of air may be disposed in the first external air inflow passage 201 . there is.

The fuel processing unit (I) may include a first internal gas flow path 102 through which the fuel gas discharged from the desulfurizer 110 flows to the reformer 140 . In the first internal gas passage 102, a proportional control valve 31, an internal fuel valve 32 for controlling the flow of fuel gas flowing into the reformer 140, and a control valve for fuel gas flowing in the internal gas passage 102 A second fuel flow meter 52 for detecting the flow rate, a fuel side check valve 83 for limiting the flow direction of the fuel gas flowing in the internal gas flow path 102, and/or a sulfur detection device 94 may be disposed. there is.

The proportional control valve 31 can adjust the flow rate and pressure of the fuel gas discharged from the desulfurizer 110 and flowing into the reformer 140 through internal/external feedback in an electrically controlled manner.

The sulfur detection device 94 may detect sulfur included in the fuel gas discharged from the desulfurizer 110 . The sulfur detection device 94 may include an indicator that changes color in response to sulfur compounds not removed by the adsorbent of the desulfurizer 110 . Here, the indicator may include phenolphthalein, a molybdenum compound, and the like.

The fuel processing unit (I) may include a second internal gas flow path 103 through which the fuel gas discharged from the desulfurizer 110 flows to the burner 120 . The burner 120 may use fuel gas introduced through the second internal gas passage 103 for combustion.

The first internal gas passage 102 and the second internal gas passage 103 may communicate with each other.

The fuel processing device 10 may be connected to the water supply passage 303 through which water discharged from the water supply tank 13 flows. In the water supply passage 303, a water pump 38, a water supply valve 39 for controlling the flow of water, and/or a water flow meter 54 for detecting the flow rate of water flowing in the water supply passage 303 are disposed. can

Exhaust gas generated by the burner 120 of the fuel processing device 10 may be discharged from the fuel processing device 10 through the exhaust gas discharge passage 210 .

The fuel processing device 10 may be connected to the reformed gas discharge passage 104 . The reformed gas discharged from the fuel processing device 10 may flow through the reformed gas discharge passage 104 .

The reformed gas discharge passage 104 may be connected to the reformed gas heat exchanger 21 in which heat exchange of reformed gas occurs. A reformed gas valve 33 may be disposed in the reformed gas discharge passage 104 to control the flow of the reformed gas flowing into the reformed gas heat exchanger 21 .

The reformed gas discharge passage 104 may communicate with the bypass passage 105 through which the reformed gas discharged from the fuel processor 10 flows to the fuel processor 10 . The bypass passage 105 may be connected to the fuel processing device 10 . The reformed gas introduced into the fuel processing device 10 through the bypass passage 105 may be used as fuel for combustion in the burner 120 . A bypass valve 34 may be disposed in the bypass passage 105 to control the flow of the reformed gas flowing into the fuel processing device 10 .

The reformed gas heat exchanger 21 may be connected to the reformed gas discharge passage 104 through which the reformed gas discharged from the fuel processing device 10 flows. The reformed gas heat exchanger 21 may be connected to the cooling water supply passage 304 through which water discharged from the water supply tank 13 flows. The reformed gas heat exchanger 21 may heat-exchange the reformed gas introduced through the reformed gas discharge passage 104 and the water supplied through the cooling water supply passage 304 .

In the cooling water supply passage 304, the cooling water pump 43 for flowing the water stored in the water supply tank 13 to the reformed gas heat exchanger 21 and/or detecting the flow rate of the water flowing in the cooling water supply passage 304 A cooling water flow meter 56 may be disposed.

The reformed gas heat exchanger 21 may be connected to the stack gas supply passage 106. The reformed gas discharged from the reformed gas heat exchanger 21 passes through the stack gas supply passage 106 to the stacks 20a and 20b. can be fluid

A first separator 401 may be disposed in the stack gas supply passage 106 to control the amount of moisture included in the reformed gas. The reformed gas introduced into the first separator 401 may be discharged from the first separator 401 after moisture is removed.

Condensed water generated in the first separator 401 may be discharged from the first separator 401 and flow into the first condensate pipe 461 . A first condensate valve 471 for controlling the flow of water may be disposed in the first condensate pipe 461 .

The stacks 20a and 20b may generate electrical energy by causing an electrochemical reaction to the reformed gas introduced through the stack gas supply passage 106 . In one embodiment, when the fuel cell system 1 includes a plurality of stacks 20a and 20b, the reformed gas discharged without reacting in the first stack 20a is additionally electrochemically discharged from the second stack 20b. can cause a reaction.

The second blower 72 may be connected to the second external air introduction passage 203 communicating with the first external air introduction passage 201 and the stack-side air introduction passage 204 . The second external air introduction passage 203 may be connected to a rear end of the air filter 91 . The second blower 72 may flow air introduced through the second external air inlet passage 203 toward the stack 20 through the stack-side air inlet passage 204 .

A second air-side check valve 82 may be disposed in the second external air inlet passage 203 to restrict the flow direction of air.

An air flow meter 53 for detecting a flow rate of air flowing in the stack-side air inlet passage 204 may be disposed in the stack-side air inlet passage 204 .

The humidifier 23 can supply moisture to the air introduced through the stack-side air inlet passage 204 and discharge air containing moisture through the stack-side air supply passage 205 .

A stack-side air supply valve 36 may be disposed in the stack-side air supply passage 205 to control the flow of air supplied to the stack 20 .

The stack-side air supply passage 205 may be connected to individual supply passages 206 and 207 respectively corresponding to the stacks 20a and 20b. Air flowing through the stack-side air supply passage 205 may be supplied to the stacks 20a and 20b through the individual supply passages 206 and 207 .

The plurality of stacks 20a and 20b may be connected to each other by a gas connection passage 107 . The reformed gas discharged without reacting in the first stack 20a may flow into the second stack 20b through the gas connection passage 107 .

An additional water removal device 62 may be disposed in the gas connection passage 107 to remove water produced by condensation while the reformed gas passes through the first stack 20a.

Water generated in the additional water removal device 62 may be discharged from the additional water removal device 62 and flow into the water recovery passage 310 . A water recovery valve 45 for controlling the flow of water may be disposed in the water recovery passage 310 . The water recovery passage 310 may be connected to the water storage passage 308 .

Unreacted hydrogen (AOG) discharged without reacting in the stacks 20a and 20b may flow through the stack gas discharge passage 108 .

The AOG heat exchanger 22 may be connected to the stack gas discharge passage 108 through which unreacted hydrogen (AOG) discharged from the stacks 20a and 20b flows. The AOG heat exchanger 22 may be connected to the hot water supply passage 313 through which water discharged from the heat recovery tank 15 flows. The AOG heat exchanger 22 may heat-exchange unreacted hydrogen (AOG) introduced through the stack gas discharge passage 108 and water supplied through the hot water supply passage 313 .

In the hot water supply passage 313, a hot water pump 48 for flowing the water stored in the heat recovery tank 15 to the AOG heat exchanger 22 and/or a hot water flow meter for detecting the flow rate of the water flowing in the hot water supply passage 313 (55) can be placed.

The AOG heat exchanger 22 may be connected to the AOG supply passage 109 and may discharge unreacted hydrogen (AOG) heat-exchanged through the AOG supply passage 109 . Unreacted hydrogen (AOG) discharged from the AOG heat exchanger 22 may flow to the fuel processing device 10 through the AOG supply passage 109 . Unreacted hydrogen (AOG) supplied to the fuel processing device 10 through the AOG supply passage 109 may be used as fuel for combustion of the burner 120 .

In the AOG supply passage 109, the flow of unreacted hydrogen (AOG) supplied to the second separator 402 and/or the fuel processing device 10 for controlling the amount of moisture contained in the unreacted hydrogen (AOG) An AOG valve 35 for adjusting may be disposed. Unreacted hydrogen (AOG) flowing into the second separator 402 may be discharged from the second separator 402 after moisture is removed.

Condensate generated in the second separator 402 may be discharged from the second separator 402 and flow through the second condensate pipe 462 . A second condensate valve 472 for controlling the flow of water may be disposed in the second condensate pipe 462 . The second condensate pipe 462 may be connected to the water supply tank 13 .

The stack-side air discharge passage 211 may be connected to individual discharge passages 208 and 209 respectively corresponding to the stacks 20a and 20b. Air discharged from the stacks 20a and 20b may flow to the stack-side air discharge passage 211 through the individual discharge passages 208 and 209 . At this time, air flowing through the stack-side air discharge passage 211 may include moisture generated by an electrochemical reaction occurring in the stacks 20a and 20b.

A stack-side air discharge valve 37 may be disposed in the stack-side air discharge passage 211 to control the flow of air discharged from the stack 20 .

The stack-side air discharge passage 211 may be connected to the humidifier 23 . The humidifier 23 may supply moisture to air flowing into the stack 20 by using moisture included in air supplied through the stack-side air discharge passage 211 . Air supplied to the humidifier 23 through the stack-side air discharge passage 211 may pass through the humidifier 23 and be discharged to the humidifier discharge passage 212 .

The water supply tank 13 may be connected to the water inflow passage 301 and may store water supplied through the water inflow passage 301 . In the water inlet passage 301, a first liquid filter 92 for removing foreign substances contained in water supplied from the outside and/or a water inlet valve 41 for controlling the flow of water flowing into the water supply tank 13 can be placed.

The water supply tank 13 may be connected to the water discharge passage 302 and may discharge at least a part of the water stored in the water supply tank 13 to the outside through the water discharge passage 302 . A water discharge valve 42 may be disposed in the water discharge passage 302 to control the flow of water discharged from the water supply tank 13 .

The water supply tank 13 may be connected to the water storage passage 308 and may store water flowing through the water storage passage 308 . For example, water discharged from the additional water removing device 62 and/or the third separator 403 may flow into the water supply tank 13 via the water storage passage 308 . A second liquid filter 93 may be disposed in the water storage passage 308 to remove foreign substances included in the water returned to the water supply tank 13 .

At least some of the water stored in the water supply tank 13 may flow to the reformed gas heat exchanger 21 by the cooling water pump 43 and may exchange heat with the reformed gas in the reformed gas heat exchanger 21 . Water discharged from the reformed gas heat exchanger 21 may flow into the stacks 20a and 20b through the stack water supply passage 305 .

Water introduced into the stacks 20a and 20b through the stack water supply passage 305 may cool the stacks 20a and 20b. Water introduced into the stacks 20a and 20b may flow along a stack heat exchanger (not shown) included in the stacks 20a and 20b, and the water generated by the electrochemical reaction occurring in the stacks 20a and 20b can absorb heat.

The plurality of stacks 20a and 20b may be connected by a water connection passage 306 . Water discharged from the first stack 20a may flow into the second stack 20b through the water connection passage 306 .

Water discharged from the stacks 20a and 20b may flow into the cooling water heat exchanger 24 through the stack water discharge passage 307 . The cooling water heat exchanger 24 may perform heat exchange between the water discharged from the stacks 20a and 20b and the water discharged from the heat recovery tank 15 . Water discharged from the stacks 20a and 20b may flow to the water storage passage 308 via the cooling water heat exchanger 24 .

Water discharged from the heat recovery tank 15 by the hot water pump 48 may flow into the AOG heat exchanger 22 via the hot water supply passage 313 . The water heat-exchanged with unreacted hydrogen (AOG) in the AOG heat exchanger 22 may be discharged to the first hot water circulation circuit 314 .

The air heat exchanger 25 may be connected to the humidifier discharge passage 212 through which air discharged from the humidifier 23 flows. The air heat exchanger 25 may be connected to the first hot water circulation circuit 314 through which water discharged from the AOG heat exchanger 22 flows. The air heat exchanger 25 may heat exchange air introduced through the humidifier discharge passage 212 and water introduced through the first hot water circulation circuit 314 .

Air heat-exchanged in the air heat exchanger 25 may be discharged from the air heat exchanger 25 through the air discharge passage 213 . The air discharge passage 213 may communicate with the exhaust gas discharge passage 210 , and the exhaust gas flowing in the exhaust gas discharge passage 210 and the air flowing in the air discharge passage 213 may be mixed.

A third separator 403 may be disposed in the air discharge passage 213 . The third separator 403 may control the amount of moisture contained in the air discharged to the outside. Air introduced into the third separator 403 may be discharged from the third separator 403 after moisture is removed.

Condensed water generated in the third separator 403 may be discharged from the third separator 403 and flow through the third condensate pipe 463 . A third condensate valve 473 for controlling the flow of water may be disposed in the third condensate pipe 463 . The third condensate pipe 463 may be connected to the water storage passage 308 .

Water heat-exchanged in the air heat exchanger 25 may be discharged from the air heat exchanger 25 through the second hot water circulation passage 315 . Water discharged from the air heat exchanger 25 may flow into the cooling water heat exchanger 24 through the second hot water circulation passage 315 .

The cooling water heat exchanger 24 may heat exchange water introduced through the stack water discharge passage 307 and water introduced through the second hot water circulation passage 315 .

The exhaust heat exchanger 26 may be connected to the exhaust gas discharge passage 210 through which exhaust gas flows. The exhaust heat exchanger 26 may be connected to the third hot water circulation passage 316 through which the water discharged from the cooling water heat exchanger 24 flows. The exhaust heat exchanger 26 may heat-exchange the exhaust gas introduced through the exhaust gas outlet passage 210 and the water introduced through the third hot water circulation passage 316 .

Exhaust gas heat-exchanged in the exhaust heat exchanger 26 may be discharged to the exhaust passage 214 , and exhaust gas flowing in the exhaust passage 214 may be discharged to the outside.

Water heat-exchanged in the exhaust heat exchanger 26 may be discharged to the hot water recovery passage 317 , and water flowing in the hot water recovery passage 317 may flow into the heat recovery tank 15 .

The fuel cell system 1 may further include a thermometer (or temperature sensor) for sensing temperature.

For example, the fuel cell system 1 includes a first thermometer 482 disposed in the reformed gas discharge passage 104 and sensing the temperature of the reformed gas flowing in the reformed gas discharge passage 104; and a second thermometer 484 disposed in the stack gas supply passage 106 and detecting a temperature of the reformed gas flowing in the stack gas supply passage 106 .

The first thermometer 482 detects the temperature of the reformed gas supplied to the first separator 401, and the second thermometer 484 measures the temperature of the reformed gas discharged from the first separator 401 and supplied to the stack 20. temperature can be sensed. Accordingly, the control unit may calculate the moisture content of the reformed gas flowing through the first separator 401 based on the difference between the temperature values sensed by the thermometers 482 and 484 .

Alternatively, the fuel cell system 1 may include a moisture sensor (not shown) to detect the moisture content of the reformed gas flowing through the first separator 401 . For example, the moisture sensor may use an infrared moisture sensor or an infrared absorption method using a two-color infrared moisture meter, a microwave moisture measurement method, an electrical resistance moisture measurement method, conductivity, and the like.

Meanwhile, the fuel cell system 1 may further include at least one controller (not shown). The controller may include at least one processor. Here, the processor may be a general processor such as a central processing unit (CPU). Of course, the processor may be a dedicated device such as an ASIC or other hardware-based processor.

The controller may control overall operations of the fuel cell system 1 . The control unit may be connected to each component provided in the fuel cell system 1 and may transmit and/or receive signals between each component. For example, the controller may process a signal received from each component included in the fuel cell system 1, and send a control signal according to a result of processing the signal to each component included in the fuel cell system 1. can be sent

Hereinafter, the arrangement of the separator 400 of the fuel cell system 1 and the connection relationship between the separator 400 and the water supply line 410 and the drain line 420 will be described with reference to FIG. 3 .

Referring to FIG. 3 , the fuel cell system 1 may include a separator 400 that collects gas moisture through heat exchange between cold water and gas flowing in the system. Moisture collected in the separator 400 is stored in the water supply tank 13 through the condensate pipes 461, 462, and 463 in the form of condensed water, and can be recycled in the system (see FIG. 2). At this time, the gas flowing into the separator may correspond to reformed gas, unreacted hydrogen (AOG), and/or air.

The fuel cell system 1 may include water supply pipes 411 , 412 , and 413 branched from a water supply line 410 through which cold water flows, connected to the separator 400 , and supplying cold water to the separator 400 . . Here, the water supply line 410 may be connected to a water supply point (not shown) where cold water is used, such as a building, and may supply cold water from a water supply source (not shown) to the water supply point according to a user's request.

The fuel cell system 1 includes a water supply line 410, a drain line 420 for discharging cold water to the outside, and drain pipes 421 and 422 connected to the separator 400 and through which the cold water discharged to the separator 410 flows. , 423).

The fuel cell system 1 may include a gas pipe through which gas flows in the system. The gas pipe connects the fuel processing device 10 (specifically, a reformer) and the stack 20, and guides the reformed gas discharged from the fuel processing device 10 to the stack 20. First gas pipes 104 and 106 ); Second gas pipes 108 and 109 connecting the fuel processing device 10 (specifically, a burner) and the stack 20 and guiding unreacted hydrogen (AOG) discharged from the stack 20 to the fuel processing device 10 ); and third gas pipes 208 , 209 , 211 , 212 , and 213 connected to the stack 20 and through which air discharged from the stack 20 flows.

The separator 400 is disposed in the first gas pipe 106 and collects condensate generated through heat exchange between reformed gas discharged from the fuel processing device 10 and cold water supplied from the water supply pipe 411. (401); A second separator 402 disposed in the second gas pipe 108 and collecting condensate generated through heat exchange between unreacted hydrogen (AOG) discharged from the stack 20 and cold water supplied from the water supply pipe 412; and a third separator 403 disposed in the third gas pipe 213 and collecting condensed water generated through heat exchange between air discharged from the stack 20 and cold water supplied from the water supply pipe 413. .

The first separator 401 may be disposed in the stack gas supply passage 106 and may receive reformed gas from the fuel processing device 10 .

The first separator 401 may be connected to the first water supply pipe 411 and may receive cold water through the water supply line 410 . Here, the first water supply pipe 411 may branch from the water supply line 410 at the upstream side of the water supply line 410, and for example, the inlet end of the first water pipe 411 and the upstream portion of the water supply line 410 are Y It can be composed of a Y-tube.

The first separator 401 may be connected to the first drain pipe 421 and may discharge cold water heat-exchanged with the reformed gas in the first separator 401 to the outside through the drain line 420 . Here, the first drain pipe 421 may join the drain line 420, and for example, the outlet end of the drain pipe 421 and the drain line 420 may be configured as a Y-tube.

The first separator 401 may be connected to the first condensate pipe 461 and supply the condensed water collected in the first separator 401 to the water supply tank 13 .

The second separator 402 may be disposed in the stack gas discharge passage 108 and may receive unreacted hydrogen (A0G) discharged after unreacting from the stack 20 .

The second separator 402 may be connected to the second water supply pipe 412 and may receive cold water through the water supply line 410 . Here, the second water supply pipe 412 may be branched from the first water supply pipe 411, and for example, the first water supply pipe 411 and the second water supply pipe 412 may be configured as a Y-tube.

The second separator 402 may be connected to the second drain pipe 422 and may discharge cold water heat-exchanged with unreacted hydrogen (AOG) in the second separator 402 through the drain line 420 to the outside. . Here, the second drain pipe 422 may join the first drain pipe 421, and for example, the first drain pipe 421 and the second drain pipe 422 may be configured as a Y-tube.

The second separator 402 may be connected to the second condensate pipe 462 and supply the condensed water collected in the second separator 402 to the water supply tank 13 .

The third separator 403 may be disposed in the air discharge passage 213, and air discharged from the stack 20 and passed through the humidifier 23 and/or the air heat exchanger 25 may be supplied.

The third separator 403 may be connected to the third water supply pipe 413 and may receive cold water through the water supply line 410 . Here, the third water supply pipe 413 may branch from the first water supply pipe 411 .

The third separator 403 may be connected to the third drain pipe 423 and discharge cold water heat exchanged with air in the third separator 403 to the outside through the drain line 420 . Here, the third drain pipe 423 may join the first drain pipe 421 .

The third separator 403 may be connected to the third condensate pipe 463, and may supply the condensed water collected in the third separator 403 to the water supply tank 13 through the water storage passage 308.

The fuel cell system 1 may include drain valves 431 and 432 disposed in a drain pipe and supplying cold water discharged from the separator 400 to a water supply line 410 or a drain line 420 .

The drain valves 431 and 432 are connected to the water supply line 410 and control the flow of cold water from the separator 400 to the water supply line 410. The first drain valve 431 and the drain line 420 It may include a second drain valve 432 that is connected and controls the flow of cold water from the separator 400 to the drain line 420 . Here, the second drain valve 432 may be a three-way valve capable of adjusting its opening.

The first drain valve 431 may be disposed in a guide pipe 424 branched from the first drain pipe 421 and connected to a downstream side of the water supply line 410 . Here, one end of the guide pipe 424 branches off from the first drain pipe 421 and extends, and the other end may be connected to the water supply line 410 in the form of a Y-tube. The first drain valve 431 may be opened so that cold water heat-exchanged in the separator 400 is supplied to the water supply line 410 when water is being supplied to a water supply point (not shown) such as a building. Therefore, even when water is being supplied to the water supply point, it is possible to smoothly maintain the amount of water used by the water supply point.

The second drain valve 432 may be disposed in the first drain pipe 421 . The second drain valve 432 may be adjusted so that cold water heat-exchanged in the separator 400 is supplied to the drain line 420 when there is no amount of water supplied to a water supply point (not shown) such as a building. Accordingly, it is possible to maintain phase separation efficiency in the separator 400 by preventing cold water heat-exchanged in the separator 400 from being supplied to the water supply line 410 and being re-supplied to the separator 400 .

The fuel cell system 1 may include flow meters 451 and 452 that detect the flow rate of cold water.

The flowmeters 451 and 452 are disposed in the water supply line 410, the first flowmeter 451 detects the flow rate of cold water flowing through the water supply line 410, and disposed in the drain pipe 421 and It may include a second flow meter 452 for detecting the flow rate of cold water flowing through.

The first flow meter 451 may be disposed at an inlet end of the water supply line 410 . Accordingly, the first flowmeter 451 may detect the total water supply amount of cold water supplied to a water supply source (not shown) such as a building and to the separator 400 .

The second flow meter 452 may be disposed in the first drain pipe 421 . Accordingly, the second flow meter 452 may detect the discharge flow rate of cold water discharged after heat exchange in the separator 400 .

The fuel cell system 1 may further include a water supply pump 440 disposed in the guide pipe 424 . The water supply pump 440 may form a certain water pressure so that the cold water flowing through the guide pipe 424 flows into the water supply line 410 .

Hereinafter, with reference to FIGS. 4 and 5 , the operation of each component of the system during the preheating operation (WM) or reforming operation (RM) of the fuel cell system 1 will be described.

The fuel cell system 1 may operate in a preheating mode (WM) in which the reformer 140 is preheated with the burner 120 to reach a temperature suitable for reforming. At this time, the internal temperature of the reformer 140 may gradually increase to an appropriate temperature (eg, 800° C.) at which the reforming reaction is promoted.

In the preheating mode (WM), the fuel cell system 1 may cut off the supply of fuel gas to the reformer 140 . For example, in the fuel cell system 1, the proportional control valve 31 is adjusted so that all of the fuel gas discharged from the desulfurizer 110 is supplied to the burner 120, so that the amount of fuel gas for the reformer 140 is reduced. Supply can be cut off (see Fig. 2).

Referring to FIG. 4 , in the preheating mode (WM), the fuel cell system 1 may close all of the reformed gas valve 33 , the bypass valve 34 , and the AOG valve 35 . At this time, since the supply of fuel gas to the reformer 140 is cut off, reformed gas is not generated in the reformer 140 . In the reformed gas discharge passage 104, the bypass passage 105, and the AOG supply passage 109, the reformed gas or anode-off gas (AOG) does not flow.

After the preheating mode (WM), the fuel cell system 1 may be operated in a reforming mode (RM) in which the reformed gas is recycled to the burner and reforming is repeated so that the concentrations of hydrogen and carbon monoxide in the reformed gas reach concentrations suitable for power generation. .

In the reforming mode (RM), the fuel cell system 1 has a proportional control valve ( 31) can be adjusted.

Meanwhile, the fuel cell system 1 may supply water to the steam generator 130 of the fuel processing device 10 by driving the water pump 38 so that steam used in the reforming reaction is supplied to the reformer 140. there is. At this time, in the fuel cell system 1, when the pressure of steam supplied to the reformer 140 is maintained above the minimum pressure for the reforming reaction, for example, when a predetermined time elapses after the water pump 38 is driven, Some of the fuel gas discharged from the desulfurizer 110 may be supplied to the reformer 140 (see FIGS. 1 and 2).

Referring to FIG. 5 , in the reforming mode (RM), the fuel cell system 1 may close the reformed gas valve 33 and the AOG valve 35 and open the bypass valve 34 . At this time, the reformed gas discharged from the fuel processing device 10 may be introduced into the fuel processing device 10 again through the reformed gas discharge flow path 104 and the bypass flow path 105, and the burner 120 may burn. can be used as a fuel for

However, the preheating mode (WM) and the reforming mode (RM) are operation modes corresponding to preparation steps for the power generation mode (PM), and in the preheating mode (WM) and the reforming mode (RM), the separator 400 reforms No gas, unreacted hydrogen (AOG) and/or air is supplied. Therefore, in order to cut off unnecessary cold water supply to the separator 400, the first drain valve 431 and the second drain valve 432 may be adjusted to be closed. In addition, the water pump 440 may maintain a stopped state without operating.

After the reforming mode (RM), the fuel cell system 1 may be operated in the power generation mode (PM) in which electricity is generated in the stacks 20a and 20b through an electrochemical reaction between air and reformed gas.

In the power generation mode (PM), the fuel cell system 1 opens the reformed gas valve 33 so that the reformed gas discharged from the fuel processing device 10 is supplied to the stack 20, and the bypass valve 34 ) can be closed. In addition, the fuel cell system 1 may open the AOG valve 35 so that unreacted hydrogen (AOG) discharged from the stack 20 flows into the fuel processing device 10 . Unreacted hydrogen (AOG) flowing into the fuel processing device 10 may be used as fuel for combustion of the burner 20 .

Meanwhile, the fuel cell system 1 may supply air used in an electrochemical reaction generating electricity to the stack 20 by driving the second blower 72 . Also, the fuel cell system 1 may open the stack-side air supply valve 36 so that air humidified by the humidifier 23 is supplied to the stack 20 . In addition, the fuel cell system 1 may open the stack-side air discharge valve 37 so that air discharged from the stack 20 passes through the humidifier 23 and is discharged to the outside.

Hereinafter, with reference to FIG. 6 , operations of each component of the system when water is supplied to a water supply point such as a building during PM operation of the fuel cell system 1 will be described.

Referring to FIG. 6 , the separator 400 may receive cold water from the water supply line 410 through the water supply pipes 411 , 412 , and 413 . At this time, the gas flowing in the separator and the cold water supplied from the water supply line 410 may exchange heat with each other, and accordingly, the moisture contained in the gas flowing in the separator is condensed and returned to the water supply tank 13. can be supplied.

Specifically, in the case of the first separator 401 , cold water may be supplied from the water supply line 410 through the first water supply pipe 411 . At this time, the reformed gas discharged from the fuel processing device 10 and flowing in the first separator 401 can be cooled by the cold water supplied from the water supply line 410, and the moisture contained in the reformed gas is condensed. The moisture content of the reformed gas can be reduced.

In the case of the second separator 402 , cold water may be supplied from the water supply line 410 through the second water supply pipe 412 . At this time, the unreacted hydrogen (AOG) discharged from the stack 20 and flowing in the second separator 402 can be cooled by the cold water supplied from the water supply line 410, and the unreacted hydrogen (AOG) The contained moisture can be condensed and the moisture content of unreacted hydrogen (AOG) can be reduced.

In the case of the third separator 403, cold water can be supplied from the water supply line 410 through the third water supply pipe 413, and air discharged from the stack 20 and flowing in the third separator 403, It is cooled by the cold water supplied from the water supply line 410 and the moisture content contained in the air can be reduced.

Thereafter, the cold water heat-exchanged in the respective separators 401 , 402 , and 403 may be discharged from the respective separators 401 , 402 , and 403 and flow in the respective drain pipes 421 , 422 , and 423 .

At this time, the fuel cell system 1 may detect the total water supply amount of cold water flowing through the water supply pipes 411 , 412 , and 413 and the water supply line 410 through the first flow meter 451 . In addition, the fuel cell system 1 may detect the total discharge amount of cold water discharged from each separator 400 and flowing through the drain pipes 421 , 422 , and 423 through the second flow meter 452 .

In the fuel cell system 1, when the total amount of cold water supplied by the first flow meter 451 is greater than the total displacement amount of cold water detected by the second flow meter 452, the cold water discharged from the separator 400 is connected to the guide pipe. The first drain valve 431 may be opened and the second drain valve 432 may be closed so that water is supplied to the water supply line 410 through the water supply line 424 . In addition, the fuel cell system 1 may operate the feed water pump 440 to form a certain water pressure so that cold water flowing through the guide pipe 424 flows into the feed water line 410 . Accordingly, even when water is being supplied to a water supply point (not shown) with a large amount of water supply, the cold water supplied to the separator 400 is recovered through the water supply line 410 to smoothly maintain the water supply amount at the water supply point.

Hereinafter, with reference to FIG. 7 , the operation of each component of the system when the amount of water used in a water supply source such as a building is low or there is no use of water during power generation operation of the fuel cell system 1 according to an embodiment of the present invention will be described. .

Referring to FIG. 7 , the separator 400 may receive cold water from the water supply line 410 through the water supply pipes 411 , 412 , and 413 . At this time, the gas flowing in the separator and the cold water supplied from the water supply line 410 may exchange heat with each other, and accordingly, the moisture contained in the gas flowing in the separator is condensed and returned to the water supply tank 13. can be supplied. The flow of cold water supplied to each separator 400 and the process of heat exchange between gas and cold water have been described in detail with reference to FIG.

Thereafter, the cold water heat-exchanged in the respective separators 401 , 402 , and 403 may be discharged from the respective separators 401 , 402 , and 403 and flow in the respective drain pipes 421 , 422 , and 423 .

At this time, the fuel cell system 1 may detect the total water supply amount of cold water flowing through the water supply pipes 411 , 412 , and 413 and the water supply line 410 through the first flow meter 451 . In addition, the fuel cell system 1 may detect the total discharge amount of cold water discharged from each separator 400 and flowing through the drain pipes 421 , 422 , and 423 through the second flow meter 452 .

In the fuel cell system 1, when the total amount of cold water supplied by the first flow meter 451 is equal to or smaller than the total amount of cold water discharged by the second flow meter 452, the cold water discharged from the separator 400 is The first drain valve 431 may be closed and the second drain valve 432 may be opened so that the water is discharged to the outside through the drain line 420 . Accordingly, when there is little or no water used at the water supply point (not shown), cold water heat-exchanged in the separator 400 flows into the water supply line 410 to prevent tepid cold water from being supplied to the separator 400 again. The phase separation efficiency of the separator 400 can be maintained.

Hereinafter, a control method of the fuel cell system 1 according to an embodiment of the present invention will be described with reference to FIG. 8 .

Referring to FIG. 8 , the controller may start the operation of the fuel cell system 1 (S100).

After S100, the controller may determine the current operation mode of the fuel cell system 1 (S110).

When the current operation mode of the fuel cell system 1 is the preheating mode (WM) (S200), the control unit sets the system to the preheating mode (WM) so that the reformer 140 of the fuel processor 10 is preheated to a temperature suitable for reforming. can be operated normally (see FIG. 4).

After S200, the control unit may stop the water supply pump 440 and close the first drain valve 431 and the second drain valve 432 to prevent cold water from being supplied to the separator 400. (S210).

When the current operation mode of the fuel cell system 1 is the reforming mode (RM) (S300), the control unit reforms the reformed gas discharged from the fuel processing device 10 so that the concentrations of hydrogen and carbon monoxide reach concentrations suitable for power generation. The system can be operated normally in the mode (RM) (refer to FIG. 5).

After S300, the controller may open the bypass valve 34 so that the reformed gas discharged from the fuel processing device 10 is supplied to the burner 120 (S310). At this time, the controller may close the reformed gas valve 33.

After S310, the control unit may stop the water supply pump 440 and close the first drain valve 431 and the second drain valve 432 in order to prevent cold water from being supplied to the separator 400. (S210).

When the current operation mode of the fuel cell system 1 is the power generation mode (PM) (S400), the controller may normally operate the system in the power generation mode (PM) so that power is generated in the stack 20.

After S400, the controller may open the stack-side air supply valve 36 and the stack-side air discharge valve 37 so that air is supplied or discharged from the stack 20 (S405).

After S405, the control unit may close the bypass valve 34 so that reformed gas is supplied to the stack 20 (S410) and open the reformed gas valve 33 (S415). In addition, the control unit may open the AOG valve 35 so that unreacted hydrogen (AOG) discharged from the stack 20 is supplied to the fuel processing device 10 (S420).

After S420, the control unit may detect the total amount of water supplied and the total amount of displacement (S430). Specifically, the control unit may detect the total amount of cold water flowing into the water supply pipe or the water supply line through the first flow meter 451, and detect the total amount of discharge of cold water flowing through the drain pipe through the second flow meter 452. can Here, the total displacement may be referred to as the drain flow rate.

After S430, the control unit may compare the total water supply amount detected in S420 with the total displacement amount to determine whether water is supplied to a water supply point such as a building (S440). Specifically, the control unit may determine that water is being supplied to a water supply point such as a building when the total water supply amount is greater than the total displacement amount, and may determine that water is not supplied to a water supply point such as a building when the total water supply amount is equal to or less than the total displacement amount. there is.

If the total water supply amount is greater than the total displacement amount (Yes in S440), the controller may open the first drain valve 431 and close the second drain valve 432 (S450). Accordingly, the cold water discharged from the separator 400 may flow in the guide pipe 424 and communicate with the water supply line 410 .

After S450, the control unit may operate the water supply pump 440 (S460). At this time, the control unit may adjust the feed water pump 440 so that the flow rate of cold water supplied to the separator 400 varies according to the moisture content of the reformed gas supplied to the stack 20 . For example, the control unit may estimate the moisture content of the reformed gas based on the difference T between the temperature values detected by the first thermometer 482 and the second thermometer 484, and determine the moisture content of the reformed gas. Accordingly, the rotational speed of the water supply pump 440 may be adjusted. Specifically, when the temperature difference (ΔT) between the first thermometer 482 and the second thermometer 484 is higher than the set value, the control unit determines that the water content of the reformed gas is high, and the flow rate of cold water supplied to the separator 400 The water supply pump 440 may be adjusted to increase. In addition, when the temperature difference (ΔT) between the first thermometer 482 and the second thermometer 484 is lower than the set value, the control unit determines that the water content of the reformed gas is low, and the flow rate of cold water supplied to the separator 400 is reduced. The water supply pump 440 may be adjusted to decrease. Here, the set value may mean a temperature difference corresponding to the moisture content of the reformed gas set to be suitable for an electrochemical reaction with air in the stack 20 . For another example, the control unit may adjust the water supply pump 440 by detecting the moisture content of the reformed gas through a moisture sensor (not shown).

When the total water supply amount is equal to or less than the total displacement amount (No in S440), the control unit may stop the water supply pump 440 and close the first drain valve 431 (S470). Accordingly, the cold water discharged from the separator 400 is blocked from entering the guide pipe 424 and can communicate with the drain line 420 .

After S470, the controller may open the second drain valve 432 (S480). At this time, the control unit may adjust the second drain valve 432 so that the flow rate of cold water discharged to the drain line 420 varies according to the moisture content of the reformed gas supplied to the stack 20 . For example, the control unit may estimate the moisture content of the reformed gas based on the difference T between the temperature values detected by the first thermometer 482 and the second thermometer 484, and determine the moisture content of the reformed gas. Accordingly, the opening amount of the second drain valve 432 may be adjusted. Specifically, when the temperature difference (ΔT) between the first thermometer 482 and the second thermometer 484 is higher than the set value, the control unit determines that the water content of the reformed gas is high, and the cold water discharged through the drain line 420. The opening amount of the second drain valve 432 may be increased to increase the flow rate. In addition, when the temperature difference (ΔT) between the first thermometer 482 and the second thermometer 484 is lower than the set value, the control unit determines that the water content of the reformed gas is low, and the flow rate of cold water supplied to the separator 400 is reduced. The opening amount of the second drain valve 432 may be reduced so as to decrease. Here, the set value may mean a temperature difference corresponding to the moisture content of the reformed gas set to be suitable for an electrochemical reaction with air in the stack 20 . For another example, the control unit may sense the moisture content of the reformed gas through a moisture sensor (not shown) and adjust the second drain valve 432 .

After S210, S320, S460, and S480, the control unit may return to operation S110 and perform the above-described operations again according to the operation mode of the system.

The accompanying drawings are only for easy understanding of the embodiments disclosed in this specification, and the technical idea disclosed in this specification is not limited by the accompanying drawings, and all changes and equivalents included in the spirit and technical scope of the present invention It should be understood to include water or substitutes.

Similarly, while operations are depicted in the drawings in a particular order, it should not be understood that all illustrated operations must be performed, or that those operations must be performed in the specific order shown or in sequential order to obtain desired results. can In certain cases, multitasking and parallel processing can be advantageous.

In addition, although the preferred embodiments of the present invention have been shown and described above, the present invention is not limited to the specific embodiments described above, and the technical field to which the present invention belongs without departing from the gist of the present invention claimed in the claims. Of course, various modifications are possible by those skilled in the art, and these modifications should not be individually understood from the technical spirit or perspective of the present invention.

10: fuel processing device 13: water supply tank
20: stack 401: first separator
402: second separator 403: third separator
410: water supply line 411: first water supply pipe
412: second water supply pipe 413: third water supply pipe
420: drain line 421: first drain pipe
422: second drain pipe 423: third drain pipe
424: guide pipe 431: first drain valve
432: second drain valve 440: water pump
451: first flow meter 452: second flow meter

Claims (15)

A stack that generates power through an electrochemical reaction between reformed gas and air;
a fuel processing device supplying the reformed gas to the stack;
a blower supplying the air to the stack;
A separator for condensing reformed gas, unreacted hydrogen or moisture contained in the air;
a water supply pipe branched from a water supply line through which cold water flows and connected to the separator, and supplying cold water to the separator;
a drain pipe connected to the water supply line, a drain line for discharging cold water to the outside, and the separator, and through which the cold water discharged from the separator flows;
and a drain valve disposed in the drain pipe and supplying cold water discharged from the separator to the water supply line or the drain line.
According to claim 1,
The drain valve,
a first drain valve connected to the water supply line and regulating the flow of cold water from the separator to the water supply line; and
and a second drain valve connected to the drain line and controlling flow of cold water from the separator to the drain line.
According to claim 2,
a first flowmeter disposed in the water supply line and sensing a flow rate of cold water flowing through the water supply line; and
a second flowmeter disposed in the drain pipe and sensing a flow rate of cold water flowing through the drain pipe; and
and a control unit adjusting the drain valve based on the cold water flow rate calculated by the first flow meter and the second flow meter.
According to claim 3,
The control unit,
Calculate the total water supply amount based on the flow rate of cold water detected by the first flow meter, and calculate the drainage flow rate of the separator based on the flow rate of cold water detected by the second flow meter,
and opening the first drain valve and closing the second drain valve so that the cold water discharged from the separator flows into the water supply line when the total water supply amount is greater than the drain flow rate of the separator.
According to claim 3,
The control unit,
Calculate the total water supply amount based on the flow rate of cold water detected by the first flow meter, and calculate the drainage flow rate of the separator based on the flow rate of cold water detected by the second flow meter,
and closing the first drain valve and opening the second drain valve so that the cold water discharged from the separator flows into the drain line when the total amount of supplied water is less than or equal to the drain flow rate of the separator.
According to claim 5,
a first thermometer for sensing the temperature of the reformed gas supplied to the separator; and
A second thermometer for sensing the temperature of the reformed gas supplied to the stack,
The control unit,
The fuel cell system for calculating the moisture content of the reformed gas based on the difference between the temperature values detected by the thermometers, and adjusting the opening of the second drain valve according to the moisture content of the reformed gas.
According to claim 5,
The second drain valve is a fuel cell system that is a three-way valve capable of adjusting the opening.
According to claim 2,
A guide pipe connecting the drain pipe and the water supply line and guiding the cold water discharged from the separator to the water supply line,
The first drain valve is disposed in the guide pipe.
According to claim 8,
and a water supply pump disposed in the guide pipe and generating water pressure so that cold water flowing through the guide pipe flows into the water supply line.
According to claim 9,
a first thermometer for sensing the temperature of the reformed gas supplied to the separator;
a second thermometer for sensing the temperature of the reformed gas supplied to the stack; and
and a control unit that calculates a moisture content of the reformed gas based on a difference in temperature values detected by the thermometers and adjusts the water supply pump according to the moisture content of the reformed gas.
According to claim 1,
a first gas pipe connecting the fuel processing device and the stack and guiding the reformed gas discharged from the fuel processing device to the stack;
a second gas pipe connecting the fuel processing device and the stack and guiding unreacted hydrogen discharged from the stack to the fuel processing device;
and a third gas pipe connected to the stack and through which air discharged from the stack flows.
According to claim 11,
The separator,
a first separator disposed in the first gas pipe and collecting condensate generated through heat exchange between reformed gas discharged from the fuel processing device and cold water supplied from the water supply pipe;
a second separator disposed in the second gas pipe and collecting condensed water generated through heat exchange between unreacted hydrogen discharged from the stack and cold water supplied from the water supply pipe; and
and a third separator disposed in the third gas pipe and collecting condensed water generated through heat exchange between air discharged from the stack and cold water supplied from the water supply pipe.
A stack that generates power through an electrochemical reaction between reformed gas and air; a fuel processing device supplying the reformed gas to the stack; a blower supplying the air to the stack; A separator that receives cold water from the water supply line and condenses reformed gas, unreacted hydrogen or moisture contained in the air; and a drain valve supplying cold water discharged from the separator to a water supply line or a drain line,
Calculating a total water supply amount of cold water flowing through the water supply line and a discharged water discharged from the separator based on the flow rate value sensed by the flow meter; and
and adjusting the drain valve by comparing the total amount of water supplied with the amount of water discharged so that cold water discharged from the separator flows into the water supply line or the drain line.
According to claim 13,
The drain valve,
a first drain valve connected to the water supply line and regulating the flow of cold water from the separator to the water supply line; and
A second drain valve connected to the drain line and regulating the flow of cold water from the separator to the drain line;
The adjusting of the drain valve may include opening the first drain valve and closing the second drain valve so that cold water discharged from the separator flows into the water supply line when the total water supply amount is greater than the drain flow rate of the separator. A control method of a fuel cell system comprising steps.
According to claim 13,
The drain valve,
a first drain valve connected to the water supply line and regulating the flow of cold water from the separator to the water supply line; and
A second drain valve connected to the drain line and regulating the flow of cold water from the separator to the drain line;
The adjusting of the drain valve may include closing the first drain valve so that cold water discharged from the separator flows into the drain line when the total amount of supplied water is equal to or less than the drain flow rate of the separator, and closing the second drain valve. A control method of a fuel cell system comprising the step of opening.

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