KR101806498B1 - A Flash Tank for Supplying Highly Dried Steam - Google Patents

Abstract

The present invention relates to a flash tank structure capable of supplying steam with improved dryness by supplying heat such as waste heat and brine wasted in industrial fields in a heat exchange provided in a flash tank, and a method for supplying steam with improved dryness. The flash tank to which high-pressure inflow water is input and in which the high-pressure inflow water is separated into steam and water to supply the steam to the outside, comprises: an inflow unit (32) through which the inflow water flows in; a condensate accommodation unit (39) which is provided to be lower than the inflow unit (32), and accommodates condensate, which does not become steam, of the inflow water flowing into the flash tank through the inflow unit; and a heat exchanger which is provided to be above the inflow unit (32), and performs heat exchange with steam evaporated after flowing in through the inflow unit. The method for supplying steam with improved dryness by using the flash tank according to the present invention comprises: a step of allowing high-pressure water to flow into the flash tank; and a step of supplying fluid at a higher temperature than that of the inflow water to the heat exchanger to secondarily heat steam in the flash tank.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flash tank for supplying steam,

The present invention relates to a flash tank, and more particularly, to a flash tank structure and a flash tank structure capable of supplying steam with a heat exchanger in a flash tank and supplying heat, such as waste heat and brine discharged from an industrial site, To an improved method of supplying steam.

A flash tank is a structure for supplying steam (steam). When a high-temperature high-pressure water is supplied into a flash tank, a part of high-pressure water which suddenly expands in volume causes a phase change to steam, Generating and supplying the same.

The high pressure water entering the flash tank instantaneously causes a volume expansion, which produces some steam and condensate. However, the steam generated by this instantaneous pressure drop is the steam with low quality, that is, the steam with much water. Low-modulus steam (steam with high moisture content) can cause shortening of life of piping and major equipment. Also, since the steam having a low quality is not a high quality steam, it is difficult to supply it as it is.

Conventionally, a method has been employed in which a demister or a mist eliminator is mounted before the steam outlet of the flash tank, and a steam separator is installed at the steam outlet pipe to improve the steam quality.

However, this is not a method of phase-changing the moisture of a low-grade steam to a steam, but a method of condensing with water, so that the steam quality can be improved, but the amount of steam itself is limited.

Japanese Patent Publication No. 4972421 Japanese Patent Publication No. 5593902 Japanese Patent Publication No. 5593906

SUMMARY OF THE INVENTION It is an object of the present invention to provide a flash tank capable of providing enhanced steam and a method of supplying steam having improved quality using the flash tank.

In order to solve the above-described problems, the present invention provides a flash tank in which high-pressure inflow water is introduced and separated by water and supplies steam to the outside, the flash tank comprising: an inflow portion (32) into which the inflow water flows; A condensed water accommodating portion 39 provided below the inflow portion 32 to receive water as condensed water which does not become vapor among inflow water introduced into the flash tank through the inflow portion; And a heat exchanger disposed above the inlet (32) and performing heat exchange with the vapor introduced after flowing through the inlet (32).

The fluid supplied to the heat exchanger is isolated from mixing with the steam in the flash tank.

The temperature of the fluid supplied to the heat exchanger is higher than the temperature of the influent water, so that the heat exchanger improves the steam quality of the steam.

Alternatively, the temperature of the fluid supplied to the heat exchanger may be lower than the temperature of the influent water, so that the heat exchanger may perform a water separating action to suppress the generation of steam and increase the generation of condensed water.

The heat exchanger is a coil type.

And a drain portion 34 for discharging the condensed water to the outside is provided in the lower portion of the condensed water accommodating portion 39. And a level gauge 42 for measuring the condensed water level of the condensed water receiving portion. When the level of the condensed water measured by the level gauge exceeds the reference level, the condensed water is discharged through the drain portion.

The amount of fluid flowing into the heat exchanger is controlled based on at least one of the pressure in the flash tank and the vapor temperature.

The amount of the fluid supplied to the heat exchanger is controlled so as to decrease as the pressure in the flash tank is higher.

The higher the steam temperature in the flash tank, the more the amount of fluid supplied to the heat exchanger is controlled to be reduced.

The fluid temperature T1 at the inlet of the heat exchanger is compared with the fluid temperature T2 at the exit of the heat exchanger. The larger the difference between the two temperatures T1-T2, the greater the amount of fluid supplied. Is controlled to be reduced.

A cover plate (50) is provided between the heat exchanger and the inflow section in the flash tank to remove condensed water from the steam and distribute the flow of the steam evenly.

At least a part of the outer peripheral surface of the cover plate is supported by the inner wall of the flash tank. A drainage passage (52) is formed on the outer circumferential surface of the cover plate so that condensed water removed from the steam can flow down to the bottom of the flash tank. The cover plate is inclined so as to gradually decrease from the central portion to the outer circumferential surface.

On the surface of the cover plate, a pore is formed.

The flash tank further includes a safety valve (46) opened when the pressure of the steam rises above a predetermined pressure. The safety valve is installed above the heat exchanger. The pressure of the steam is measured by a pressure sensor 44 provided above the heat exchanger.

And the fluid in the heat exchanger may be a refrigerant, a waste heat discarded in an industrial process, or a brine.

According to another aspect of the present invention, there is provided a method of supplying steam having improved quality using the flash tank, comprising: introducing high pressure water into a flash tank; And supplying a fluid having a temperature higher than that of the inflow water to the heat exchanger to heat the steam in the flash tank.

The level of the condensed water generated in the flash tank is measured and the condensate is drained when the level exceeds the reference level.

 As the pressure in the flash tank increases, the amount of fluid supplied to the heat exchanger decreases, and as the pressure in the flash tank decreases, the amount of fluid supplied to the heat exchanger increases.

The amount of the refrigerant supplied to the heat exchanger is decreased as the temperature T3 of steam in the flash tank is higher and the amount of the refrigerant supplied to the heat exchanger is increased as the temperature of steam in the flash tank is lower.

 The fluid temperature T1 at the inlet of the heat exchanger of the flash tank is compared with the fluid temperature T2 at the exit of the heat exchanger to increase the amount of fluid supplied as the difference between the two temperatures T1-T2 increases, Increases the amount of supplied fluid.

 When the pressure of the steam in the flash tank rises to a predetermined pressure or higher, the steam is released to the outside of the flash tank.

According to the present invention, it is possible to supply steam having improved dryness with a simple structure.

The above and other objects, features and advantages of the present invention will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG.

1 is a schematic view showing an entire structure of a flash tank according to an embodiment of the present invention, and FIG.
2 and 3 are a plan view and a side view of an embodiment of a cover plate installed in a flash tank of a heat pump system according to an embodiment of the present invention.

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

It is to be understood that the present invention is not limited to the disclosed embodiments, but may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, It is provided to inform.

 [Structure of Flash Tank]

1 is a schematic view showing the overall structure of a flash tank according to an embodiment of the present invention.

The flash tank 30 is an enclosure having an inner space isolated from the outside as shown. The flash tank 30 has an inlet 32 at the lower side and a discharge valve 36 at the upper end. A drain portion 34 is provided at a lower end of the flash tank 30.

High-temperature high-pressure water flows into the inner space of the flash tank 30 through the inflow portion 32. When the high-temperature high-pressure water is suddenly introduced into the flash tank 30 with a large space, the volume expands and the pressure is lowered, so that some influent water is vaporized and steam is generated. The non-vaporized influent water portion becomes condensate and falls to the lower portion of the flash tank, and the lower space of the flash tank 30 lower than the inlet portion 32 becomes the condensate water receiving portion 39.

A level gauge 42 is provided on a side surface of the flash tank 30. [ The level gauge 42 measures and senses the level of condensate contained in the flash tank 30. When the level of the condensed water received in the receiving portion 39 is higher than the reference height provided at a position lower than the inlet 32, the level gauge 42 opens the drain portion 34 to discharge the condensed water to the outside of the flash tank 30 .

The condensate discharged to the outside of the flash tank 30 is again heated by the waste heat water or the like and is reheated in such a manner that it is heat-exchanged with the condenser portion of the heat pump that recovers the heat of the waste heat water, And flows into the flash tank at a high temperature and a high pressure. The high-pressure water supplied to the flash tank 30 is continuously replenished from the outside.

On the other hand, the vapor vaporized from the high-pressure water flowing into the flash tank 30 through the inlet 32 rises upwards and some of the vapor that has risen upward may be condensed again and fall to the bottom of the flash tank .

The level gauge 42 may perform an operation to replenish the water when the water level inside the flash tank is too low. Also, the water to be supplemented may not be supplied directly to the inside of the flash tank but may be supplied in such a manner as to join the pipe of the drain portion 34. [ Since the water to be replenished may be relatively low in temperature, it is preferable that the water is supplied to the flash tank after being heated from the outside rather than supplied to the flash tank which must maintain a high temperature environment.

A cover plate (50) is installed in the flash tank (30) at an upper portion of the inflow part (32). Referring to FIG. 1, the cover plate 50 is installed in the flash tank by being supported by the inner wall of the flash tank 30 at least a part of the outer circumferential surface thereof.

2 and 3 are a plan view and a side view of an embodiment of a cover plate installed in a flash tank according to an embodiment of the present invention. Referring to FIG. 2, a cover 54 is provided on the cover plate 50. The replenishment unit 54 functions to disperse the steam evenly when the water vapor introduced into the flash tank through the inlet unit rises in the flash tank. This allows heat exchange to occur more smoothly between the heat exchanger 18 and the water vapor to be described later.

As described above, the outer circumferential surface of the cover plate 50 is fixed to the inner circumferential surface of the flash tank, and the cover plate 50 may be in the shape of a cap having the highest center as in FIG. 3 and a lower height as it goes to the outer circumference. And the inclination angle a may be approximately 1 to 3 degrees. If the inclination angle is 3 DEG or more, the steam dispersion function is degraded. If the inclination angle is less than 1 DEG, some of the steam passing through the cover plate 50 is liquefied again, so that the water formed on the cover plate does not move smoothly, There is a problem that the water formed on the cover plate 50 accelerates the liquefaction of water vapor.

As shown in FIG. 2, a cover-shaped cover plate is formed with a drainage passage 52 on the outer circumference thereof. The drainage channel may be in the form of a groove as shown. Accordingly, the water formed on the cover plate in the shape of a hat can be moved to the edge and fall into the condensate receiving portion 39 below the flash tank 30 through the drainage passage 52.

The level gauge 42 and the inlet 32 described above are located below the cover plate 50.

A heat exchanger (18) is located above the cover plate (50). The fluid is introduced into the heat exchanger 18, and heat exchange is performed between the fluid inside the heat exchanger and the steam inside the flash tank. When the temperature of the fluid inside the heat exchanger is higher than the steam temperature inside the flash tank, the steam inside the flash tank is heated from the heat exchanger to promote vaporization of the vapor in the steam. Thus, the vapor quality of the vapor is improved by the high temperature fluid supplied to the heat exchanger in the flash tank.

The heat exchanger 18 secures the two spaces so that the fluid flowing inside the heat exchanger is not mixed into the heat exchanger exterior, i.e., the flash tank interior space. In addition, considering the fact that heat is exchanged for the rising steam, the heat exchanging efficiency with the steam is further improved by constituting the coil type heat exchanger as shown in the present invention. To be more specific, the side surface of the flash tank itself may be formed in a cylindrical shape so as to effectively withstand a high internal pressure, and a coil type heat exchanger having a columnar shape that can geometrically correspond to the cylindrical flash tank By applying the group, the heat exchange efficiency for the rising steam can be further enhanced in the present invention. Of course, the central axis of the cylindrical shape of the flash tank and the central axis of the heat exchanger can be aligned with each other.

As described above, the heat exchanger 18 is configured to re-heat the steam to reliably vaporize the moisture contained in the steam to improve the dryness. Therefore, the steam temperature in the flash tank If it is high, it can be controlled so that the fluid does not flow through the heat exchanger, and the amount of the fluid flowing to the heat exchanger can be adjusted according to the degree of reheating of the steam.

There may be a pressure in the flash tank as a control factor for controlling the flow rate of the fluid flowing into the heat exchanger and the flow rate. A pressure sensor 44 is installed in the flash tank to constantly monitor the internal pressure. A high pressure in the flash tank may mean that the temperature of the vapor in the flash tank is higher. Therefore, according to the embodiment of the present invention, the amount of the fluid flowing into the heat exchanger decreases as the pressure inside the flash tank increases, and the amount of the fluid flowing into the heat exchanger increases as the pressure inside the flash tank decreases.

Other control factors that control the flow of the refrigerant or adjust the flow rate may be the temperature in the flash tank. At this time, the amount of the fluid flowing into the heat exchanger decreases as the temperature inside the flash tank increases, and the amount of the fluid flowing into the heat exchanger increases as the temperature inside the flash tank decreases.

The other control factors for controlling the fluid flow or controlling the fluid flow to the heat exchanger may be the fluid temperature T1 of the fluid inlet portion of the heat exchanger 18 and the fluid temperature T2 of the fluid outlet portion of the heat exchanger 18. [ That is, the fluid temperature (T1) at the inlet of the heat exchanger in the flash tank is compared with the fluid temperature (T2) at the outlet of the heat exchanger. The difference between the two temperatures (T1-T2) It can be said that there is a lot of heat exchange. In this case, it can be judged that it is necessary to increase the flow amount of the fluid in order to further increase the temperature of the steam. On the contrary, if the difference between the two temperatures (T1-T2) is small, it means that the heat exchange is low and the heat exchange occurs little because the temperature difference between the fluid and the water vapor is small. In this case, it can be judged that the flow amount of the fluid may be reduced. Therefore, the larger the difference between the two temperatures (T1-T2), the larger the amount of fluid supplied, and the smaller the temperature difference, the smaller the amount of fluid supplied.

As described above, according to the present invention, it is possible to make the steam having a low degree of quality secondarily heated by the heat exchanger to produce high quality steam having high quality. In particular, when the steam is secondarily heated through the heat exchanger according to the present invention to increase the dryness, the pressure of the steam can be further increased compared with the conventional method.

In view of the above, in the present invention, the pressure sensor 44 is installed on the upper part of the heat exchanger of the flash tank. The pressure sensor 44 constantly monitors the pressure inside the flash tank, particularly the pressure of the steam that has risen through the heat exchanger. If the internal pressure is detected to be excessively high as a result of the monitoring, the steam is partially released through the safety valve 46 provided at the top of the flash tank to prevent the flash tank from being damaged or exploded. The safety valve is also installed above the heat exchanger, so that the pressure in the region of the flash tank with the highest pressure can be solved most directly and effectively.

The flash tank heat exchanger is provided with a discharge valve 36 on the upper part thereof to control the amount of steam supplied to the industrial site. The steam discharged through the discharge valve 36 and supplied to each industrial site is secondarily heated by the heat exchanger to improve the dryness of the steam. There is no fear of shortening the service life of the piping and the main equipment. Which is more beneficial for utilization in the industrial field.

On the other hand, the fluid flowing into the heat exchanger can utilize refrigerant or waste heat, brine or the like, which is discharged from an industrial site.

In the case of the fluid flowing into the heat exchanger, R-245fa refrigerant can be used, for example, in the present invention, considering that the temperature required for improving the quality and producing high-quality steam is about 120 degrees centigrade. And the waste heat of the industrial site is mostly around 60 degrees Celsius, which is low temperature to be supplied directly to the heat exchanger. Accordingly, the refrigerant is subjected to the compression-condensation-expansion-evaporation process, the waste heat of the industrial site is recovered in the evaporation process, the refrigerant in the gaseous phase is made hot through the compression and then introduced into the heat exchanger, It is possible to improve the dryness by heating the steam in the second heat.

Also, the heat generated during the process of condensing the compressed high-temperature refrigerant is used to heat the condensed water discharged through the drain portion 34 of the flash tank, or to heat the water supplied to the flash tank, It is possible to generate high-temperature high-pressure water to be introduced into the inside.

The above-described flash tank having a heat exchanger can be used in a manner of secondarily heating the vapor inside the flash tank through a heat exchanger, or can be used in the form of a water separator. For example, if the fluid flowing into the heat exchanger is lower than the temperature of the inflow water flowing into the flash tank, it is possible to use steam as a water separator since the generation of steam can be suppressed and the generation of condensed water can be increased.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the scope of the invention is not limited to the disclosed exemplary embodiments. It is obvious that a transformation can be made. Although the embodiments of the present invention have been described in detail above, the effects of the present invention are not explicitly described and described, but it is needless to say that the effects that can be predicted by the configurations should also be recognized.

18: Heat exchanger
30: Flash tank
32:
34: drain part
36: Discharge valve
39: Condensate receiving part
42: Level gauge
44: Pressure sensor
46: Safety valve
50: Cover plate
52: drainage
54: Pure study

Claims (22)

A flash tank in which high-pressure influent water is injected and separated by water, and which supplies steam to the outside,
The flash tank comprises:
An inlet (32) through which the inflow water flows;
A condensed water accommodating portion 39 provided below the inflow portion 32 to receive water as condensed water which does not become vapor among inflow water introduced into the flash tank through the inflow portion; And
And a heat exchanger provided above the inlet (32) and performing heat exchange with the vapor introduced after flowing through the inlet,
The fluid supplied to the heat exchanger is isolated from mixing with the steam in the flash tank,
Wherein a temperature of the fluid supplied to the heat exchanger is higher than a temperature of the inflow water, so that the heat exchanger improves the steam quality of the steam.
The method according to claim 1,
Wherein the amount of the fluid flowing into the heat exchanger is controlled based on at least one of the pressure in the flash tank and the steam temperature.
The method of claim 2,
And the amount of the fluid supplied to the heat exchanger is controlled so as to decrease as the pressure in the flash tank is higher.
The method of claim 2,
Wherein the higher the steam temperature in the flash tank is, the lower the amount of fluid supplied to the heat exchanger is.
The method of claim 2,
The fluid temperature T1 at the inlet of the heat exchanger is compared with the fluid temperature T2 at the exit of the heat exchanger. The larger the difference between the two temperatures T1-T2, the greater the amount of fluid supplied. The amount of flash tank is characterized by reduced.
The method according to claim 1,
Characterized in that a cover plate (50) is provided between the heat exchanger and the inlet in the flash tank to remove condensed water in the vapor and to evenly distribute the flow of the vapor.
The method of claim 6,
At least a part of the outer peripheral surface of the cover plate is supported by the inner wall of the flash tank,
A drainage passage (52) is formed on the outer peripheral surface of the cover plate so that condensed water removed from the steam can flow down to the bottom of the flash tank,
Wherein the cover plate is tilted so as to gradually decrease from a central portion toward an outer peripheral surface.
A flash tank in which high-pressure influent water is injected and separated by water, and which supplies steam to the outside,
The flash tank comprises:
An inlet (32) through which the inflow water flows;
A condensed water accommodating portion 39 provided below the inflow portion 32 to receive water as condensed water which does not become vapor among inflow water introduced into the flash tank through the inflow portion; And
And a heat exchanger provided above the inlet (32) and performing heat exchange with the vapor introduced after flowing through the inlet,
Between the heat exchanger and the inlet portion in the flash tank, a cover plate (50) for removing condensed water in the steam and uniformly distributing the flow of the steam is provided,
At least a part of the outer peripheral surface of the cover plate is supported by the inner wall of the flash tank,
A drainage passage (52) is formed on the outer peripheral surface of the cover plate so that condensed water removed from the steam can flow down to the bottom of the flash tank,
Wherein the cover plate is tilted so as to gradually decrease from a central portion toward an outer peripheral surface.
The method of claim 8,
Wherein the fluid supplied to the heat exchanger is isolated so as not to mix with steam in the flash tank.
The method of claim 9,
Wherein the temperature of the fluid supplied to the heat exchanger is lower than the temperature of the influent water so that the heat exchanger performs a water separating action to suppress the generation of steam and increase the generation of condensed water.
The method according to any one of claims 7 to 10,
Wherein a surface of the cover plate is polished.
The method according to any one of claims 1 to 10,
Wherein the heat exchanger is a coil type.
[13] has been abandoned due to the registration fee. The method according to any one of claims 1 to 10,
A drain (34) for discharging the condensed water stored in the condensed water receiving portion (39) to the outside is provided in the lower portion of the condensed water receiving portion (39)
And a level gauge (42) for measuring a condensed water level of the condensed water containing portion,
And discharging condensed water through the drain portion when the level of the condensed water measured by the level gauge exceeds the reference level.
[14] has been abandoned due to the registration fee. The method according to any one of claims 1 to 10,
Wherein the flash tank further comprises a safety valve (46) that is opened when the pressure of the steam rises to a predetermined pressure or higher.
[Claim 15 is abandoned upon payment of registration fee] 15. The method of claim 14,
The safety valve is installed above the heat exchanger,
The pressure of the steam is measured by a pressure sensor (44) installed above the heat exchanger.
The method according to any one of claims 1 to 9,
Wherein the fluid in the heat exchanger is a refrigerant, a waste heat discarded in an industrial process, or a brine.
A method for supplying steam with enhanced dryness using the flash tank of any one of claims 1 to 7,
Introducing high-pressure water into the flash tank; And
And supplying a fluid having a temperature higher than the inflow water to the heat exchanger to heat the steam in the flash tank.
18. The method of claim 17,
Wherein the water level of the condensed water generated in the flash tank is measured and the condensed water is drained when the water level exceeds the reference water level.
18. The method of claim 17,
Wherein the amount of the fluid supplied to the heat exchanger is increased as the pressure in the flash tank is increased, and the amount of fluid supplied to the heat exchanger is increased as the pressure in the flash tank is lower.
18. The method of claim 17,
Wherein the amount of the fluid supplied to the heat exchanger is decreased as the temperature T3 of the steam in the flash tank is higher and the amount of the fluid supplied to the heat exchanger is increased as the temperature of the steam in the flash tank is lower. Improved steam supply method.
18. The method of claim 17,
The fluid temperature T1 at the inlet of the heat exchanger of the flash tank is compared with the fluid temperature T2 at the exit of the heat exchanger to increase the amount of fluid supplied as the difference between the two temperatures T1-T2 increases, And the amount of the supplied fluid is increased.
[Claim 22 is abandoned upon payment of the registration fee.] 18. The method of claim 17,
Wherein the steam is released to the outside of the flash tank when the pressure of the steam of the flash tank rises to a predetermined pressure or more.

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