KR102541651B1 - Apparatus and method for producing high-pressure steam using waste heat of fuel cell stack - Google Patents

Abstract

The high-pressure steam production device using the waste heat of the fuel cell stack includes a fuel cell stack that produces electricity and heat using oxygen and hydrogen, a heat exchanger that recovers heat using water, and hot water generated by being heated by the recovered heat. It includes a flash vessel for producing low-pressure steam by re-evaporation after inflow, a separator for removing moisture from the low-pressure steam, and a steam recompressor for producing high-pressure steam using the low-pressure steam from which moisture has been removed.

Description

High-pressure steam production apparatus and method using waste heat of fuel cell stack {APPARATUS AND METHOD FOR PRODUCING HIGH-PRESSURE STEAM USING WASTE HEAT OF FUEL CELL STACK}

The present invention is an apparatus and method for producing high-pressure steam using waste heat from a fuel cell stack, and more specifically, recovers waste heat from a fuel cell stack to produce low-pressure steam, and produces high-pressure steam to meet the needs of customers. It relates to an apparatus and method for producing high-pressure steam using waste heat from a fuel cell stack.

A fuel cell system produces electricity and thermal energy by obtaining hydrogen from fuel such as city gas through a hydrogen extractor and then supplying the obtained hydrogen and oxygen together to a fuel cell stack. DC power generated from the fuel cell stack is finally converted into AC power of 200V-60Hz through a power inverter and transmitted to KEPCO.

On the other hand, even if hot water is produced with thermal energy generated while cooling the fuel cell stack and then supplied for heating or summer cooling in connection with district heating, the heating load and cooling load are not constant and fluctuate greatly. In particular, in recent years, global warming Due to the influence of environmental factors that do not have extreme cold/hot weather, the efficiency of energy use is gradually declining.

While the electricity generated through the fuel cell can be efficiently used in various fields, the utilization of hot water produced by thermal energy is very low.

Meanwhile, high-pressure steam is required in various industrial sites, and such high-pressure steam is usually produced by operating a boiler using LNG as a raw material. However, due to the recent war between Russia and Ukraine, the cost of importing LNG gas has rapidly increased, and the cost of high-pressure steam production has also increased rapidly.

In addition, using a large amount of LNG gas for high-pressure steam production in a situation where reducing carbon emissions is a hot topic around the world is also going against this trend.

In consideration of this point, a technology for producing high-pressure steam using waste heat from a fuel cell is being developed (refer to Korean Patent Registration No. 10-1983305), and feed water and combustion air supplied to the boiler are transferred through the heat of the fuel cell. It is heated to produce high-pressure/superheated steam.

However, this production method has low heat utilization efficiency in that it raises the temperature of feed water supplied to the boiler or raises the temperature of combustion air instead of directly using heat for cooling the fuel cell stack.

In order to solve this problem, the utilization of hot water produced through the heat of the fuel cell stack is increased, and in particular, high-pressure steam using the waste heat of the fuel cell stack that can produce high-pressure steam meeting the needs of various industrial sites with this hot water The need for production devices and methods is emerging.

The problem to be solved by the present invention is to generate hot water by heating water used for the recovery of waste heat recovered from a fuel cell stack, and then produce low-pressure steam using the generated hot water, and then use the produced low-pressure steam to various industrial sites. It is to provide an apparatus and method for producing high-pressure steam using waste heat of a fuel cell stack, which is converted into high-pressure steam that meets the needs of the above.

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

High-pressure steam production apparatus using waste heat of a fuel cell stack according to an embodiment of the present invention for solving the above problems is a fuel cell stack that produces electricity and heat using oxygen and hydrogen, and recovers heat using water. A heat exchanger that generates low-pressure steam by introducing hot water heated by the recovered heat and re-evaporating it to produce low-pressure steam, a separator that removes moisture from the low-pressure steam, and high-pressure steam using the low-pressure steam from which moisture has been removed. includes a steam recompressor that produces

A method for producing high-pressure steam using waste heat of a fuel cell stack according to an embodiment of the present invention for solving the above problems includes generating electricity and heat using oxygen and hydrogen in a fuel cell stack, cooling water flowing through a waste circulation line. The step of absorbing heat from the cooling water in the heat exchanger, the step of recovering heat from the cooling water that absorbed the heat by the circulating water flowing in the circulation line of the circulating water in the heat exchanger, the step of turning the recovered circulating water into hot water and flowing into the flash vessel, flashing The steps include producing low-pressure steam by re-evaporating hot water in the vessel, removing moisture from the low-pressure steam in a separator, and producing high-pressure steam using the low-pressure steam from which moisture has been removed in a steam recompressor.

According to the present invention, the waste heat recovered from the fuel cell stack heats the water used for the recovery to generate hot water, and then produces low-pressure steam using the generated hot water, and uses the produced low-pressure steam to meet the needs of various industrial sites. It is possible to provide an apparatus and method for producing high-pressure steam using waste heat of a fuel cell stack, which is converted into suitable high-pressure steam.

1 is a conceptual diagram of an apparatus for producing high-pressure steam using waste heat of a fuel cell stack according to an embodiment of the present invention.
2 is a process piping related diagram of a low pressure steam generation package according to an embodiment of the present invention.
3 is a view showing a low-pressure steam generating device (steam generation package) according to an embodiment of the present invention.
4 is a view showing a state in which a foreign matter removal device and a water replacement facility are installed in a cooling water waste circulation line and a circulation water circulation line of a high-pressure steam production device using waste heat of a fuel cell stack according to another embodiment of the present invention.
5 is a view showing the contaminated water discharge facility of FIG. 4;
6 is a flowchart of a method for producing high-pressure steam using waste heat of a fuel cell stack according to an embodiment of the present invention.

The present invention is not limited to the embodiments disclosed below, but will be implemented in a variety of different forms, only the present embodiments make the disclosure of the present invention complete, and those skilled in the art in the art to which the present invention belongs It is provided to fully inform the person of the scope of the invention.

In this specification, singular forms also include plural forms unless specifically stated otherwise in a phrase. As used herein, “comprises” and/or “comprising” do not preclude the presence or addition of one or more other components, steps, and operations to the stated components, steps, and operations.

Referring to FIGS. 1 to 3 , an apparatus for producing high-pressure steam using waste heat from a fuel cell stack according to an embodiment of the present invention will be described. 1 is a conceptual diagram of an apparatus for producing high-pressure steam using waste heat of a fuel cell stack according to an embodiment of the present invention. 2 is a process piping related diagram of a low pressure steam generation package according to an embodiment of the present invention. 3 is a view showing a low-pressure steam generating device (steam generation package) according to an embodiment of the present invention.

1 to 3, an apparatus for producing high-pressure steam using waste heat of a fuel cell stack according to an embodiment of the present invention includes a fuel cell stack 10, a closed cooling water circulation line 20, a heat exchanger 30, and a circulation Water circulation line (40), flash vessel (50), make-up water supply line (110), separator (70), emergency vent (80), steam recompressor and superheat It may include a desuperheater (100).

The fuel cell stack 10 is an energy generating device that produces electricity and heat using oxygen and hydrogen.

Specifically, hydrogen is obtained through a method of converting fuel such as city gas into hydrogen through a hydrogen extractor, and the obtained hydrogen and oxygen are supplied together to the fuel cell stack 10 to generate electricity and oxygen through an electrochemical reaction. can produce thermal energy.

DC power produced by the fuel cell stack 10 can be finally converted into AC power such as 200V 60Hz through an inverter and transmitted to KEPCO, and the generated heat is used by the fuel cell stack 10. It can be recovered through the cooling process to produce hot water and the like.

The closed cooling water circulation line 20 is a line through which cooling water absorbing heat (or waste heat) generated in the fuel cell stack 10 flows.

A cooling water pump may be installed on the cooling water closed circulation line 20 to circulate the cooling water.

A part of the closed cooling water circulation line 20 may be located around the fuel cell stack 10, and the cooling water flowing through the closed cooling water circulation line 20 may absorb heat of the fuel cell stack 10, and thus Accordingly, the fuel cell stack 10 may be cooled.

Since the closed cooling water circulation line 20 may have a closed structure, the cooling water therein may absorb heat from the fuel cell stack 10 while continuously flowing within the cooling water closed circulation line 20 .

The heat exchanger 30 is a device that recovers heat from the fuel cell stack 10 using water.

To this end, a part of the aforementioned closed cooling water circulation line 20 may be located in the heat exchanger 30, and a part of the circulating water circulation line 40 described later may be located in the heat exchanger 30 while flowing therein. The water can recover heat from the cooling water.

For this heat exchange, in the heat exchanger 30, the closed cooling water circulation line 20 and the circulation water circulation line 40 may be located opposite to each other, or one line may wind the other line. there is. However, if heat exchange occurs between the cooling water and the circulating water, the arrangement between them may vary.

The circulation water circulation line 40 is a line through which circulation water for recovering heat from cooling water that has absorbed heat of the fuel cell stack 10 flows.

A circulation pump may be installed on the circulation water circulation line 40 to circulate the circulation water.

A part of the circulating water circulation line 40 and the closed cooling water circulation line 20 may be located in the heat exchanger 30, and under this positional relationship, the circulating water flowing through the circulating water circulation line 40 is the closed cooling water circulation line ( Heat exchange in which heat of the fuel cell stack 10 is recovered from cooling water flowing through 20 may occur.

Through this heat exchange, the circulating water on the circulating water circulation line 40 can be heated to become hot water. As an example, the heated circulating water, that is, hot water, can be 120° C. and 2.75 bar.g (see FIG. 1 ). see A).

That is, the present invention recovers heat from the fuel cell stack 10 by using water, and more specifically, does not simply use cooling water to recover heat from the fuel cell stack 10, but instead uses heat from the cooling water. After absorbing the circulating water, a two-step process can be applied to recover heat from the cooling water.

In other words, an indirect heat exchange method may be performed between the fuel cell stack 10 that generates heat and the circulating water that recovers heat by passing cooling water therebetween.

If only the coolant without circulating water absorbs and recovers heat from the fuel cell stack 10 and passes through the flash vessel 50 through the circulation line, the coolant may be contaminated by foreign substances during this circulation process, , Since the heat of the fuel cell stack 10 cannot be effectively absorbed and recovered by the contaminated cooling water, the fuel cell stack 10 is not sufficiently cooled, resulting in low energy production efficiency and poor operation.

In addition, the circulation water circulation line 40 may be in fluid communication with a flash vessel 50 to be described later, and accordingly, the circulation water flowing through the circulation water circulation line 40 flows into the flash vessel 50 and then flows into the flash vessel 50. It flows out from 50 and can return to the circulating water circulation line 40 again.

The flash vessel 50 is a device that produces low-pressure steam using circulating water heated by the heat of the fuel cell stack 10 .

As described above, the flash vessel 50 may be located on the circulation water circulation line 40, and thus the flash vessel 50 and the circulation water circulation line 40 may be in fluid communication.

Under this structure, circulating water that has become hot water can flow into the flash vessel 50 via the flash valve 60, and the hot water can be re-evaporated in the flash vessel 50 to become low-pressure steam.

Specifically, the pressure in the flash vessel 50 may be 0.2 bar.g (at this time, the temperature of saturated steam is 105° C.), and when hot water of 120° C. and 2.75 bar.g is introduced into the flash vessel 50, hot water The temperature of can be higher than the temperature of the saturated steam in the flash vessel (50).

Accordingly, a temperature difference (120 - 105 = 15 ℃) occurs between the temperature of the hot water and the temperature of the saturated steam, and this difference can boil the hot water and cause re-evaporation.

That is, through this re-evaporation process, the circulating water, which is hot water, can become low-pressure steam, and low-pressure steam can be produced in the flash vessel 50.

In addition, the flash vessel 50 can produce circulation water as well as low-pressure steam with hot water. In other words, gas-liquid separation occurs in the flash vessel 50, and hot water can be produced separately into low-pressure steam and circulating water.

Thereafter, the low-pressure steam flows out of the flash vessel 50 and flows into a separator 70 to be described later, and the circulating water flows out of the flash vessel 50 and flows into the circulating water circulation line 40 again so that the heat exchanger ( 30) can be moved.

That is, the circulating water according to the present invention flows through the circulating water circulation line 40 to recover heat of the fuel cell stack 10 from the cooling water in the heat exchanger 30, and is introduced into the flash vessel 50 to obtain low-pressure steam and A circulation process of gas-liquid separation with circulating water and returning to the circulating water circulation line 40 may be performed.

Meanwhile, as an embodiment, the circulation water from the flash vessel 50 may be hot water at 104° C. and 5.25 bar.g, but the state of the circulation water may vary (see B in FIG. 1).

The make-up water supply line 110 is a line through which make-up water to make up for a shortage of circulating water caused by the production of low-pressure steam in the flash vessel 50 flows.

As described above, as a result of producing low-pressure steam using circulating water in the flash vessel, the flow rate of circulating water to be returned to the circulating water circulation line 40 may be insufficient.

Considering this point, in the case of the present invention, replenishment water may be supplied through the replenishment water supply line 110 .

In one form of supplying make-up water, the make-up water supply line 110 may be in fluid communication with the flash vessel 50, thereby providing make-up water to make up for the shortfall of circulating water caused by the production of low-pressure steam, It may be supplied to the flash vessel 50 through the replenishment water supply line 110 .

Alternatively, the make-up water supply line 110 may communicate with the circulating water circulation line 40, thereby supplying make-up water to supplement the shortfall of circulating water caused by the production of low-pressure steam. It can be supplied to the circulating water circulation line 40 through 110.

The separator 70 is a device that removes moisture from the low-pressure steam discharged from the flash vessel 50.

In the flash vessel 50, a large amount of water is sprayed and circulated at a high pressure, and thus low-pressure steam produced in the flash vessel 50 contains moisture, so the dryness of the low-pressure steam may be low.

When the low-pressure steam containing moisture flows directly into the steam recompressor, which will be described later, the steam recompressor and pipes may be damaged by the moisture.

In order to solve this problem, in the case of the present invention, instead of sending the low-pressure steam coming out of the flash vessel 50 directly to the steam recompressor, first, moisture (eg, condensate) contained in the low-pressure steam in the separator 70 The dryness of the low-pressure steam can be increased by removing the steam before sending it to the steam recompressor.

Meanwhile, in one embodiment, the low-pressure steam from which moisture is removed through the separator 70 may be 100° C. and 0 atm, but the state of the low-pressure steam may vary (see C in FIG. 1 ).

The emergency pressure release device 80 is a device that discharges the low-pressure steam to the outside when the low-pressure steam discharged from the separator 70 does not meet the operating conditions of the high-pressure steam production device.

Specifically, when the low-pressure steam from which moisture has been removed does not meet the operating conditions of the steam recompressor described later, or if a problem occurs in the operation of the steam recompressor, the emergency pressure discharge device 80 releases the low-pressure steam from which moisture has been removed. It is a device that discharges low-pressure steam to prevent it from being supplied to the recompressor.

For example, after the high-pressure steam production device according to the present invention is operated, if low-pressure steam sufficient to operate the steam recompressor is not generated, it is discarded through the emergency pressure discharge device 80 and the produced low-pressure steam is operated. If the conditions are satisfied, the emergency pressure relief device 80 can be closed and steam can be supplied to the recompressor.

In addition, when low-pressure steam greater than the design amount of the steam recompressor is generated during the operation of the high-pressure steam production device, it can be discharged through the emergency pressure discharge device 80.

A steam recompressor is a device that produces high-pressure steam using low-pressure steam from which moisture has been removed.

Since steam required by various industrial sites is high-pressure steam, it is necessary to turn low-pressure steam from the separator 70 into high-pressure steam.

To this end, the steam recompressor may produce high-pressure steam using low-pressure steam from which moisture is removed from the separator 70 .

In one embodiment, the high-pressure steam produced in this way may be 135 ° C. and 2.2 bar.g, but the state of the high-pressure steam may vary (see D in FIG. 1).

Such a steam recompressor may be a mechanical vapor recompressor (MVR) 90.

On the other hand, in the case of the present invention, in order to increase the high pressure of the high pressure steam produced by the mechanical vapor recompressor 90 to meet the demand of the customer, MVR suction for additionally compressing the high pressure steam may be further included.

As an example, the high-pressure steam from the mechanical vapor recompressor 90 may have a pressure of 2.2 bar.g, and certain industrial sites may require high-pressure steam of 16 bar.g.

Accordingly, high-pressure steam of 2.2 bar.g can be made into high-pressure steam of 16 bar.g by using MVR suction.

The superheat reducer 100 is a device that lowers the temperature of the high-pressure steam produced by the steam recompressor when the temperature of the high-pressure steam is higher than a set value.

High-pressure steam produced by the steam recompressor may have an excessively high temperature in some cases, and accordingly, it may be difficult to use it in an industrial field.

In order to solve this problem, the superheat reducer 100 may reduce the superheat of the high-pressure steam by spraying cooling water to the high-pressure steam.

An apparatus for producing high-pressure steam using waste heat from a fuel cell stack according to an embodiment of the present invention has been described above. Hereinafter, an apparatus for producing high-pressure steam using waste heat from a fuel cell stack according to another embodiment of the present invention will be described with reference to FIGS. 4 and 5 .

4 is a view showing a state in which a foreign matter removal device and a water replacement facility are installed in a cooling water waste circulation line and a circulation water circulation line of a high-pressure steam production device using waste heat of a fuel cell stack according to another embodiment of the present invention. 5 is a view showing the contaminated water discharge facility of FIG. 4;

Referring to FIGS. 4 and 5 , an apparatus for producing high-pressure steam using waste heat of a fuel cell stack according to another embodiment of the present invention is an apparatus for producing high-pressure steam using waste heat of a fuel cell stack according to an embodiment of the present invention described above. In, the foreign matter removal device 120 and water replacement equipment may be additionally installed.

The foreign matter removal device 120 and the water replacement facility may be installed in the closed cooling water circulation line 20 and the circulation water circulation line 40 .

First, a state in which the foreign matter removal device 120 and the water replacement facility are installed on the closed coolant circulation line 20 will be reviewed.

A foreign material removal device 120 may be installed in the closed cooling water circulation line 20 to remove foreign materials from the cooling water.

In this regard, when cooling water flows on the closed cooling water circulation line 20, scale or rust may be generated inside the closed cooling water circulation line 20, and these foreign substances may be mixed with the cooling water.

In this way, when foreign substances are included in the cooling water, the heat absorbing power of the cooling water absorbing heat of the fuel cell stack 10 may decrease, and accordingly, the fuel cell stack 10 may not be sufficiently cooled, resulting in problems in the performance of the fuel cell stack 10. may occur.

In consideration of this point, a cooling water foreign matter removal system may be additionally installed in the cooling water closed circulation line 20 .

Specifically, referring to FIG. 4 , the cooling water foreign matter removal system is located on the first cooling water bypass line 130 and the first cooling water bypass line 130 connected in parallel to the cooling water closed circulation line 20, and The foreign matter removal device 120 for removing foreign substances contained therein, the first bypass valve 140 installed on the coolant closed circulation line 20, and the foreign matter removal device 120 on the first coolant bypass line 130 on one side of the The installed second bypass valve 150 and the third bypass valve 160 installed on the other side of the foreign matter removal device 120 on the first cooling water bypass line 130 may be further included.

Under this configuration, when the electrical conductivity of the cooling water measured by the electrical conductivity sensor 250 to be described later is equal to or higher than the reference value, the first bypass valve 140 is closed, and the second bypass valve 150 and the third bypass valve 160 may be opened to allow cooling water to flow to the foreign matter removal device 120 to remove foreign matter.

Meanwhile, foreign matter removal methods of the foreign matter removal device 120 include physical treatment, chemical treatment, and electrolysis.

If the foreign matter is not sufficiently removed even after removing the foreign matter from the cooling water by the foreign matter removing device 120 and the electrical conductivity of the cooling water measured by the electrical conductivity sensor 250 is still higher than the reference value, it is determined that the cooling water can no longer be used. , additionally, contaminated cooling water can be replaced through a water replacement facility.

The water exchange facility for the cooling water includes a contaminated water discharge facility 300 and a cooling water replenishment facility 310 .

Referring to FIG. 5 , the contaminated water discharge facility 300 may be installed on the second cooling water bypass line 330 installed in parallel to the closed cooling water circulation line 20 while having a diameter smaller than that of the closed cooling water circulation line 20. there is.

That is, by installing the contaminated water discharge facility 300 on the second cooling water bypass line 330 having a smaller diameter rather than the closed cooling water circulation line 20, the contaminated water can be gradually replaced until it reaches an appropriate level of water quality. Accordingly, it is possible to prevent the system from becoming unstable due to a large amount of water being replaced at once.

The contaminated water discharge facility 300 is installed on the third cooling water bypass line 270 and the second cooling water bypass line 330 installed in parallel with the second cooling water bypass line 330, and uses differential pressure to coolant check valve 190 for flowing into the third coolant bypass line 270 and the electrical conductivity of the coolant installed on the third coolant bypass line 270 and from which foreign substances are removed by the foreign matter removal device 120 A conductivity sensor 250 for measuring, a three-way distribution valve 180 installed on the second coolant bypass line 330 to open and close the second coolant bypass line 330 and the contaminated water discharge pipe 210, and when the electrical conductivity of the cooling water from which foreign substances are removed, measured by the electrical conductivity sensor 250, is equal to or greater than the reference value, the 3-way distribution valve 180 is controlled to close the second cooling water bypass line 330 and the contaminated water discharge pipe. It may include a controller 200 that opens the 210 to discharge the contaminated cooling water.

On the other hand, the fourth bypass valve 340 installed on the closed cooling water circulation line 20, the fifth bypass valve 350 installed on one side of the contaminated water discharge facility 300 on the second cooling water bypass line 330, and a sixth bypass valve 360 installed on the other side of the contaminated water discharge facility 330 on the second cooling water bypass line 330 .

The fourth bypass valve 340 may be partially closed to form a differential pressure so that the cooling water flowing through the closed cooling water circulation line 20 flows to the polluted water discharge facility 300, and the fifth bypass valve 350 and 6 The bypass valve 360 can be fully opened.

In addition, the contaminated water discharge facility 300 may include equipment for calibrating the electrical conductivity sensor 250 .

Specifically, the contaminated water discharge facility 300 includes a pair of maintenance stop valves 220 and 230 installed on the third coolant bypass line 270 with the electrical conductivity sensor 250 interposed therebetween, a pair of After being supplied to the third coolant bypass line 270 closed by the cost stop valves 220 and 230, it flows to the conductivity sensor 250 to supply a standard solution used to calibrate the conductivity sensor 250. A supply valve 240 and a drain valve 260 for discharging the standard solution used for calibration may be included.

Next, the cooling water replenishment facility 310 is a facility that supplies uncontaminated cooling water (ie, cooling water having electrical conductivity less than a reference value) to the closed cooling water circulation line to replenish the discharged cooling water.

The cooling water replenishment facility 310 includes a make-up water inlet line, which is a path through which make-up water flows into the closed coolant circulation line 20, an inlet valve installed on the make-up water inlet line to introduce make-up water into the make-up water inlet line, and the inlet replenishment. It may include a check valve preventing the water from flowing backward and a tank for adjusting the condition of the make-up water so that the make-up water can be used as cooling water.

Next, a state in which the foreign matter removal device 120 and the water replacement facility are installed on the circulation water circulation line 40 will be examined.

A foreign material removal device 120 may be installed in the circulation water circulation line 40 to remove foreign materials from the circulating water.

In this regard, when the circulation water flows on the circulation water circulation line 40, scale or rust may occur inside the circulation water circulation line 40, and since the circulation water passes through the flash vessel 50, the circulation water In the process of flowing along the circulation water circulation line 40, foreign substances may be mixed with the circulation water.

In this way, when foreign substances are included in the circulating water, the ability of the circulating water to recover heat from the cooling water may decrease, and accordingly, the cooling water that provides less heat does not sufficiently absorb the heat of the fuel cell stack 10, and also the flash vessel ( The quality of the low-pressure steam produced by 50) may deteriorate, causing frequent operation of the emergency pressure relief device 80.

Considering this point, a circulation water foreign matter removal system may be additionally installed in the circulation water circulation line 40 .

Specifically, referring to FIG. 4 , the circulating water foreign matter removal system is located on the first circulating water bypass line 170 and the first circulating water bypass line 170 connected in parallel to the circulating water circulation line 40. and the foreign matter removal device 120 for removing foreign matter contained in the circulating water, the first bypass valve 140 installed on the circulating water circulation line 40, and the foreign matter removal on the first circulating water bypass line 170 A second bypass valve 150 installed on one side of the device 120, and a third bypass valve 160 installed on the other side of the foreign matter removal device 120 on the first circulation water bypass line 170 can do.

Under this configuration, when the electrical conductivity of the circulating water measured by the electrical conductivity sensor 250 is equal to or greater than the reference value, the first bypass valve 140 is closed, and the second bypass valve 150 and the third bypass valve ( 160) may be opened to allow circulating water to flow to the foreign matter removal device 120 to remove foreign matter.

Meanwhile, foreign matter removal methods of the foreign matter removal device 120 include physical treatment, chemical treatment, and electrolysis.

If the electrical conductivity of the circulating water measured by the electrical conductivity sensor 250 is still higher than the reference value even after removing foreign substances from the circulating water by the foreign material removal device 120, the contaminated circulating water can be additionally replaced through a water replacement facility. .

The water replacement facility includes a contaminated water discharge facility 300 and a circulating water replenishment facility 320 .

Referring to FIG. 5 , the contaminated water discharge facility 300 is installed on the second circulating water bypass line 335 installed in parallel to the circulating water circulation line 40 and having a diameter smaller than that of the circulating water circulation line 40. can be installed

That is, by installing the contaminated water discharge facility 300 on the second circulating water bypass line 335 having a smaller diameter than the circulating water circulation line 40, the contaminated water is gradually replaced until it reaches an appropriate level of water quality. Accordingly, a large amount of water can be replaced at once to prevent the system from becoming unstable.

This polluted water discharge facility 300 is installed on the third circular water bypass line 280 and the second circular water bypass line 335 installed in parallel to the second circular water bypass line 335, and through differential pressure. The check valve 190 that allows the circulation water to flow into the third circulation water bypass line 280 and circulation installed on the third circulation water bypass line 280 to remove foreign substances by the foreign matter removal device 120 The electrical conductivity sensor 250 for measuring the electrical conductivity of the water and the three-way 3-way installed on the second circulating water bypass line 335 open and close the second circulating water bypass line 335 and the contaminated water discharge pipe 210 When the electrical conductivity of the circulating water from which foreign substances are removed, measured by the distribution valve 180 and the electrical conductivity sensor 250, is greater than the reference value, the 3-way distribution valve 180 is controlled to supply the second circulating water bypass line. It may include a controller 200 that closes 335 and opens the contaminated water discharge pipe 210 so that the circulating water is discharged.

Meanwhile, the fourth bypass valve 340 installed on the circulating water circulation line 40 and the fifth bypass valve 350 installed on one side of the contaminated water discharge facility 300 on the second circulating water bypass line 335 ), and a sixth bypass valve 360 installed on the other side of the contaminated water discharge facility 330 on the second circulating water bypass line 335.

The fourth bypass valve 340 may be partially closed to form a differential pressure so that the circulating water flowing through the circulating water circulation line 40 flows to the contaminated water discharge facility 300, and the fifth bypass valve 350 and The sixth bypass valve 360 may be fully opened.

Also, as described above, the contaminated water discharge facility 300 may include equipment for calibrating the electrical conductivity sensor 250 .

Next, the circulating water replenishment facility 320 is a facility that supplies uncontaminated circulating water (ie, circulating water having electrical conductivity less than a reference value) to the circulating water circulation line 40 to replenish the discharged circulating water.

The circulating water replenishment facility 320 includes a make-up water inlet line, which is a path through which make-up water flows into the circulating water circulation line 40, an inlet valve installed on the make-up water inlet line and introducing make-up water into the make-up water inlet line, and an inlet It may include a check valve to prevent the back flow of make-up water.

In the above, an apparatus for producing high-pressure steam using waste heat of a fuel cell stack according to an embodiment of the present invention has been described. Hereinafter, a method for producing high-pressure steam using waste heat of a fuel cell stack according to an embodiment of the present invention will be described with reference to FIG. 6 . 6 is a flowchart of a method for producing high-pressure steam using waste heat of a fuel cell stack according to an embodiment of the present invention.

Referring to FIG. 6 , a method for producing high-pressure steam using waste heat of a fuel cell stack includes generating electricity and heat using oxygen and hydrogen in a fuel cell stack (S10), and cooling water flowing in a waste cooling water circulation line to generate heat. Absorbing (S20), recovering heat from the cooling water that has absorbed heat from the circulating water flowing in the circulating water circulation line in the heat exchanger (S30), and introducing the circulating water into the flash vessel as hot water (S30) S40), hot water re-evaporating in the flash vessel to produce low-pressure steam (S50), removing moisture from the low-pressure steam in the separator (S60), and using the low-pressure steam from which moisture has been removed in the steam recompressor to obtain high-pressure steam. A step of producing steam (S70) is included.

In the step of generating electricity and heat using oxygen and hydrogen in the fuel cell stack (S10), oxygen and hydrogen are supplied to the fuel cell stack 10, and an electrochemical reaction occurs between them to generate electricity and heat (or waste heat). can produce

In the step of absorbing heat by the cooling water flowing through the closed cooling water circulation line (S20), the cooling water flowing on the closed cooling water circulation line 20 while a part of the closed cooling water circulation line 20 is located around the fuel cell stack 10 Heat of the fuel cell stack 10 may be absorbed.

Additionally, as described above, the foreign matter removal device 120 and the water replacement facility are installed on the cooling water closed circulation line 20 to purify the contaminated cooling water, discharge the unusable cooling water, and then replenish new cooling water. can

In the step of recovering heat from the cooling water in which the circulating water flowing through the circulating water circulation line in the heat exchanger absorbs heat (S30), a part of the closed cooling water circulation line 20 and a part of the circulating water circulation line 40 are transferred to the heat exchanger ( 30), and the circulating water flowing through the circulating water circulation line 40 through heat exchange can recover heat from the cooling water flowing through the closed cooling water circulation line 20.

Additionally, as described above, the foreign matter removal device 120 and the water replacement facility are installed on the circulating water circulation line 40 to purify the contaminated circulating water, discharge the circulating water that is no longer usable, and then circulate it again. number can be supplemented.

In step S40 in which the circulating water from which the heat is recovered becomes hot water and is introduced into the flash vessel, the circulating water on the circulating water circulation line 40 may become hot water after recovering the heat, and the circulating water that has become hot water is supplied to the flash valve. It can flow into the flash vessel (50) through (60).

In step S50 in which hot water is re-evaporated in the flash vessel to produce low-pressure steam, the hot water introduced into the flash vessel 50 may be gas-liquid separated into low-pressure steam and circulating water through a flash vaporization process and produced.

In addition, when low-pressure steam is produced in the flash vessel 50, the circulating water produced at the same time can flow out to the circulating water circulation line 40, and the circulating water can recover heat from the cooling water in the heat exchanger 30. there is.

In addition, through the make-up water supply line 110, make-up water to make up for a shortage of circulating water caused by the production of low-pressure steam may be supplied to the flash vessel 50.

In the step of removing moisture from the low-pressure steam in the separator (S60), the low-pressure steam coming out of the flash vessel 50 can flow to the separator 70, and the moisture is removed from the low-pressure steam in the separator 70 to increase the dryness. can

In the step of producing high-pressure steam using the low-pressure steam from which moisture is removed in the steam recompressor (S70), the low-pressure steam with increased dryness can be moved to the steam recompressor, and the steam recompressor uses the low-pressure steam to produce high-pressure steam. can produce

At this time, the state of desired high-pressure steam may be different for each industrial site, and it is necessary to adjust the pressure and temperature of the high-pressure steam produced for this purpose.

In this regard, in order to increase the pressure of the high-pressure steam produced by the steam recompressor, the produced high-pressure steam may be further compressed in the MVR suction to become high-pressure steam with increased pressure.

In addition, when the temperature of the produced high-pressure steam is high, the superheat reducer 100 may lower the temperature of the produced high-pressure steam.

Although the embodiments of the present invention have been described with reference to the accompanying drawings, those skilled in the art to which the present invention pertains can be implemented in other specific forms without changing the technical spirit or essential features of the present invention. you will be able to understand Therefore, the embodiments described above should be understood as illustrative in all respects and not limiting.

10: fuel cell stack 20: closed coolant circulation line
30: heat exchanger 40: circulating water circulation line
50: flash vessel 60: flash valve
70: separator 80: emergency pressure release device
90: mechanical vapor recompressor 100: desuperheater
110: make-up water supply line 120: foreign matter removal device
130: first coolant bypass line 140: first bypass valve
150: second bypass valve 160: third bypass valve
170: first circulating water bypass line 180: three-way distribution valve
190: check valve 200: controller
210: contaminated water discharge pipe 220, 230: stop valve for maintenance
240: standard solution supply valve 250: electrical conductivity sensor
260: drain valve 270: third coolant bypass line
280: third circulating water bypass line 300: contaminated water discharge facility
310: cooling water replenishment facility 320: circulating water replenishment facility
330: second coolant bypass line 335: second circulating water bypass line
340: 4th bypass valve 350: 5th bypass valve
360: sixth bypass valve

Claims (16)

A fuel cell stack that produces electricity and heat using oxygen and hydrogen;
a heat exchanger for recovering the heat using water;
A flash vessel for generating low-pressure steam by re-evaporating hot water generated by being heated by the recovered heat;
a separator for removing moisture from the low-pressure steam; and
A steam recompressor for producing high-pressure steam using the low-pressure steam from which the moisture has been removed;
a closed cooling water circulation line, a portion of which is located in the heat exchanger and is a cooling water flow path for absorbing the heat; and
Further comprising a circulating water circulation line, which is a flow path of circulating water, a part of which is located in the heat exchanger and recovers the heat from the cooling water that has absorbed the heat;
The high-pressure steam production apparatus using the waste heat of the fuel cell stack, wherein the circulating water from which the heat is recovered becomes the hot water and flows into the flash vessel.
delete According to claim 1,
an electrical conductivity sensor measuring electrical conductivity of the cooling water;
a first cooling water bypass line connected in parallel to the cooling water closed circulation line;
a foreign matter removal device positioned on the first coolant bypass line and removing foreign matter contained in the coolant;
a first bypass valve installed on the cooling water closed circulation line;
a second bypass valve installed on one side of the foreign matter removal device on the first cooling water bypass line; and
Further comprising a third bypass valve installed on the other side of the foreign matter removal device on the first cooling water bypass line,
When the electrical conductivity of the cooling water measured by the electrical conductivity sensor is equal to or greater than the reference value, the first bypass valve is closed and the second bypass valve and the third bypass valve are opened so that the cooling water is removed from the foreign matter removing device. A device for producing high-pressure steam using waste heat of a fuel cell stack to remove foreign substances by flowing into the According to claim 3,
When the electrical conductivity of the cooling water from which foreign substances are removed by the foreign matter removing device is greater than or equal to the reference value, the second cooling water bypass line has a diameter smaller than that of the closed cooling water circulation line and is installed in parallel to the closed cooling water circulation line. Contaminated water discharge facility for discharging to the outside; and
The high-pressure steam production device using waste heat of the fuel cell stack further comprising a cooling water replenishment facility for supplying cooling water to the closed cooling water circulation line to supplement the discharged cooling water. According to claim 4,
The contaminated water discharge facility,
a third cooling water bypass line installed in parallel with the second cooling water bypass line;
a check valve installed on the second cooling water bypass line and allowing cooling water to flow into the third cooling water bypass line;
an electrical conductivity sensor installed on the third cooling water bypass line to measure electrical conductivity of the cooling water from which foreign substances are removed;
a three-way distribution valve installed on the second cooling water bypass line to open and close the second cooling water bypass line and the contaminated water discharge pipe; and
When the electrical conductivity of the cooling water from which the foreign substances are removed, measured by the electrical conductivity sensor, is equal to or greater than the reference value, the 3-way distribution valve is controlled to close the second cooling water bypass line and the contaminated water discharge pipe is opened to discharge the cooling water. A device for producing high-pressure steam using waste heat of a fuel cell stack, including a controller for discharging. According to claim 5,
a pair of stop valves for maintenance installed on the third coolant bypass line with the electrical conductivity sensor interposed therebetween;
a standard solution supply valve supplying a standard solution used to calibrate the electrical conductivity sensor after being supplied to the third coolant bypass line closed by the pair of maintenance stop valves and then flowing to the electrical conductivity sensor; and
A high-pressure steam production device using waste heat of a fuel cell stack comprising a drain valve for discharging the standard solution used for calibration. According to claim 1,
an electrical conductivity sensor for measuring electrical conductivity of the circulating water;
a first circulation water bypass line connected in parallel to the circulation water circulation line;
a foreign matter removal device positioned on the first circulating water bypass line and removing foreign matter included in the circulating water;
a first bypass valve installed on the circulation water circulation line;
a second bypass valve installed on one side of the foreign matter removal device on the first circulating water bypass line; and
Further comprising a third bypass valve installed on the other side of the foreign matter removal device on the first circulation water bypass line;
When the electrical conductivity of the circulating water measured by the electrical conductivity sensor is equal to or greater than the reference value, the first bypass valve is closed, and the second bypass valve and the third bypass valve are opened so that the circulating water removes the foreign matter. A device for producing high-pressure steam using waste heat from a fuel cell stack that flows into the device to remove foreign substances. According to claim 7,
The electrical conductivity of the circulating water installed on the second circulating water bypass line having a diameter smaller than that of the circulating water circulation line and installed in parallel to the circulating water circulation line, and from which the foreign matter is removed by the foreign matter removal device, is Contaminated water discharge facility that discharges circulating water to the outside when it is above the standard value; and
High-pressure steam production apparatus using waste heat from a fuel cell stack, further comprising a circulating water replenishment facility for supplying circulating water to the circulating water circulation line to replenish the discharged circulating water. According to claim 8,
The contaminated water discharge facility,
a third circulation water bypass line installed in parallel with the second circulation water bypass line;
a check valve installed on the second circulating water bypass line and allowing the circulating water to flow into the third circulating water bypass line;
an electrical conductivity sensor installed on the third circulating water bypass line to measure electrical conductivity of circulating water from which foreign substances are removed;
a three-way distribution valve installed on the second circulating water bypass line to open and close the second circulating water bypass line and the polluted water discharge pipe; and
When the electrical conductivity of the circulating water from which foreign substances are removed, measured by the electrical conductivity sensor, is equal to or greater than the reference value, the 3-way distribution valve is controlled to close the second circulating water bypass line and the contaminated water discharge pipe is opened to circulate An apparatus for producing high-pressure steam using waste heat of a fuel cell stack comprising a controller that allows water to be discharged. According to claim 1,
The flash vessel separates and produces the hot water into the low-pressure steam and the circulating water,
The circulating water flows out to the circulating water circulation line to recover the heat in the heat exchanger. According to claim 10,
and a make-up water supply line for supplying make-up water to the flash vessel to make up for the shortfall of the circulating water generated by the production of the low-pressure steam. According to claim 10,
The apparatus for producing high-pressure steam using waste heat of a fuel cell stack further comprising a supplemental water supply line supplying supplemental water to the circulating water circulation line to make up for a shortage of the circulating water generated due to the production of the low-pressure steam. According to claim 1,
When the low-pressure steam from which the water is removed does not meet the operating conditions of the steam recompressor, an emergency pressure discharge device for discharging low-pressure steam to prevent the low-pressure steam from which the water is removed from being supplied to the steam recompressor A high-pressure steam production device using waste heat of a fuel cell stack further comprising a vent). generating electricity and heat using oxygen and hydrogen in a fuel cell stack;
absorbing the heat with cooling water flowing through a closed cooling water circulation line;
recovering the heat from the cooling water in which the circulating water flowing in the circulating water circulation line in the heat exchanger absorbs the heat;
converting the circulating water from which the heat is recovered into hot water and flowing into a flash vessel;
re-evaporating the hot water in the flash vessel to produce low-pressure steam;
removing moisture from the low-pressure steam in a separator; and
A method of producing high-pressure steam using waste heat of a fuel cell stack, comprising: generating high-pressure steam using the low-pressure steam from which the water is removed in a steam recompressor. 15. The method of claim 14,
and recovering the heat from the cooling water in the heat exchanger by flowing the circulating water simultaneously produced when the low-pressure steam is produced in the flash vessel to the circulating water circulation line. High pressure steam production method. According to claim 15,
The method of producing high-pressure steam using waste heat of a fuel cell stack, further comprising supplying supplemental water to the flash vessel through a supplementary water supply line to make up for the shortage of the circulating water generated due to the production of the low-pressure steam.

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