JP2020118305A - Steam heat exchange system - Google Patents

Abstract

To reduce a loss of steam and prevent deterioration of a heat transmission coefficient in a heat exchanger.SOLUTION: A steam heat exchange system 1 includes: a first heat exchanger 24 which conducts heat exchange between steam supplied by a steam supply source 20 and a heated object to send drainage generated in the heat exchange from a delivery port 40 with a part of the steam supplied by the steam supply source 20; a separator 60 which separates the drainage supplied from the delivery port 40 of the first heat exchanger 24 from the steam; and a second heat exchanger 50 which is supplied with the steam separated from the separator 60 to conduct heat exchange between the supplied steam and a heated object.SELECTED DRAWING: Figure 1

Description

The present invention relates to steam heat exchange systems.

A steam heat exchange system has been proposed in which steam generated in a boiler is supplied to a heat exchanger, and heat is exchanged between the steam and an object to be heated (for example, air) in the heat exchanger (for example, Patent Document 1). ).

JP, 7-119918, A

In the pipe in which the steam flows in the heat exchanger, the latent heat of the steam is used for heating the object to be heated to generate drainage. The drain may be formed in a film shape on the inner surface of the tube of the heat exchanger and may stay in the tube. In the steam heat exchange system, when drainage stays in the tubes of the heat exchanger, the heat transmission coefficient (ease of heat transfer to the object to be heated) in the heat exchanger decreases.

Therefore, it is conceivable to increase the amount of steam supplied to the heat exchanger per unit time, that is, the flow velocity of the steam, and to send the drain accumulated in the pipe of the heat exchanger to the outside of the heat exchanger by the steam. ..

However, in the mode in which the drain accumulated in the pipe of the heat exchanger is sent to the outside of the heat exchanger by the steam, the steam is also sent together with the drain, so the steam is wastefully discharged without being used for heat exchange (steam). Is large).

The present invention has been made in view of the above problems, and an object thereof is to provide a steam heat exchange system capable of preventing a decrease in heat transmission coefficient in a heat exchanger while suppressing steam loss.

In order to solve the above problems, the steam heat exchange system of the present invention performs heat exchange between the steam supplied from the steam supply source and the object to be heated, and the drain generated by the heat exchange is supplied from the steam supply source. First heat exchanger that sends out from the outlet together with a part of the steam that is supplied, a separator that separates the drain and the steam that are supplied from the outlet of the first heat exchanger, and the steam that is separated by the separator. And a second heat exchanger that exchanges heat between the supplied steam and the object to be heated.

In addition, a steam distribution unit that guides the steam separated by the separator to the second heat exchanger, and an orifice that is provided in the steam distribution unit and that narrows the cross-sectional area of a predetermined section of the flow path in the steam distribution unit may be provided. Good.

In addition, a pressure adjusting valve provided between the separator and the orifice in the steam circulation unit for changing the opening of the flow path in the steam circulation unit, and on the downstream side of the first heat exchanger in the route through which the steam flows. Yes A pressure gauge provided on the primary steam distribution path upstream of the pressure adjustment valve for detecting the pressure of steam flowing through the primary steam distribution path, and the opening of the pressure adjustment valve based on the pressure of the pressure gauge. And a control unit that controls the degree.

In addition, a pressure adjusting valve provided between the separator and the orifice in the steam circulation unit for changing the opening of the flow path in the steam circulation unit, and on the downstream side of the first heat exchanger in the passage through which the drain flows. A thermometer that is provided in the primary-side drain flow path that is upstream of the trap that collects the drain separated by the separator, and that detects the temperature of the drain that flows in the primary-side drain flow path; And a control unit that controls the opening degree of the pressure control valve based on the temperature.

Further, a pressure adjusting valve which is provided between the separator and the orifice in the steam flowing portion and changes the opening of the flow path in the steam flowing portion, and between the pressure adjusting valve and the orifice or between the orifice and the second heat exchanger. A pressure gauge, which is provided between the pressure gauge and the pressure gauge, detects the pressure of the steam flowing through the steam flow section, and a control section that controls the opening of the pressure adjusting valve based on the pressure of the pressure gauge.

In addition, an electric valve provided between the separator and the orifice in the steam distribution unit and switching between opening and closing of the flow path in the steam distribution unit, and between the electric valve and the orifice in the steam distribution unit or the orifice and the second heat exchanger. And a pressure gauge for detecting the pressure of the steam flowing through the steam flow section, and when the pressure of the pressure gauge exceeds a predetermined first threshold value, the electric valve is closed and the pressure of the pressure gauge is set to the first pressure. A control unit may be provided that opens the motor-operated valve when it falls below a predetermined second threshold value that is smaller than the threshold value.

In addition, the pressure of the internal space is set below atmospheric pressure, the drain separated by the separator is supplied to the internal space, and a flash tank that generates flash vapor from the supplied drain is provided. May be supplied to the second heat exchanger.

According to the present invention, it is possible to prevent a decrease in the heat transmission coefficient in a heat exchanger while suppressing steam loss.

It is a schematic diagram showing composition of a steam heat exchange system by a 1st embodiment. It is a front view which shows the structural example of a 1st heat exchanger. It is a left side view of the III direction of FIG. FIG. 4 is a right side view in the IV direction of FIG. 2. It is a flow chart for explaining operation at the time of starting in the steam heat exchange system of a 1st embodiment. It is a flow chart explaining operation of a control part based on pressure of a pressure gauge. It is a flowchart explaining operation|movement of the control part based on the temperature of a thermometer. It is a schematic diagram showing composition of a steam heat exchange system by a 2nd embodiment. It is a schematic diagram showing composition of a steam heat exchange system by a 3rd embodiment. It is explanatory drawing for demonstrating operation|movement of the steam heat exchange system of 3rd Embodiment. It is a schematic diagram showing composition of a steam heat exchange system by a 4th embodiment.

Aspects of embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in the embodiments are merely examples for facilitating understanding of the invention, and do not limit the invention unless otherwise specified. In this specification and the drawings, elements having substantially the same function and configuration are denoted by the same reference numerals to omit redundant description, and elements not directly related to the present invention are omitted. To do.

(First embodiment)
FIG. 1 is a schematic diagram showing the configuration of the steam heat exchange system 1 according to the first embodiment. In FIG. 1, the signal flow is indicated by a dashed arrow, and the directions of water, steam, and drain flows are indicated by solid arrows. In the following, configurations and processes related to this embodiment will be described in detail, and descriptions of configurations and processes unrelated to this embodiment will be omitted.

The steam heat exchange system 1 includes a water supply tank 10, a steam supply source 20, a first heat exchanger 24, a first pressure reducing valve 28, an air vent valve 30, a second heat exchanger 50, a second pressure reducing valve 56, a separator 60, and The thermometer 68, the pressure adjusting valve 70, the pressure gauge 72, the orifice 74, the check valve 76, the air vent valve 78, and the controller 80 are included.

The water supply tank 10 is formed, for example, in a tubular shape, and stores water supplied through the makeup water pipe 12. Further, drainage is collected in the water supply tank 10 from a first trap 14, a second trap 16, and a third trap 18, which will be described later.

A water supply pipe 22 is provided between the water supply tank 10 and the steam supply source 20. The water supply tank 10 supplies the stored water to the steam supply source 20 through a water supply pipe 22.

The steam supply source 20 is, for example, a boiler. The steam supply source 20 heats the water supplied from the water supply tank 10 to generate high-pressure steam. A first inlet pipe 26 is provided between the steam supply source 20 and the first heat exchanger 24. The steam supply source 20 sends the generated steam to the first heat exchanger 24 through the first inlet pipe 26. The steam supply source 20 is pressure-controlled so that the pressure of the steam to be sent out becomes a predetermined pressure. The pressure of the steam delivered from the steam supply source 20 is, for example, 0.8 MPaG. In addition, PaG shows the gauge pressure which is a relative pressure on the basis of atmospheric pressure.

The first inlet pipe 26 is provided with a first pressure reducing valve 28. The first pressure reducing valve 28 lowers the pressure of the steam on the first heat exchanger 24 side with respect to the pressure of the steam on the steam supply source 20 side with respect to the first pressure reducing valve 28 in the first inlet pipe 26. The steam decompressed by the first pressure reducing valve 28 is sent to the first heat exchanger 24.

When the steam pressure is 0.8 MPaG, the steam temperature is about 175°C. When the steam pressure is 0.5 MPaG, the steam temperature is about 150°C. For example, when steam of about 150° C. is required in the first heat exchanger 24, the pressure of the steam supplied to the first heat exchanger 24 is changed from 0.8 MPaG to about 0.5 MPaG by the first pressure reducing valve 28. The pressure is reduced. Thereby, the steam having an appropriate temperature can be supplied to the first heat exchanger 24. Moreover, since the latent heat increases when the pressure of the steam is reduced, the efficiency of heat exchange in the first heat exchanger 24 can be increased.

When steam of about 175° C. is required in the first heat exchanger 24, the first pressure reducing valve 28 is not provided, and 0.8 MPaG of steam is directly supplied from the steam supply source 20 to the first heat exchanger 24. You may.

An air vent valve 30 is provided on the first inlet pipe 26. For example, at the time of starting the steam heat exchange system 1 or the like, air may remain in the first inlet pipe 26. If there is air in the first inlet pipe 26, the temperature of the steam becomes lower than the saturation temperature, and the efficiency of heat exchange in the first heat exchanger 24 may decrease.

The air vent valve 30 opens while the temperature in the first inlet pipe 26 is below or below a predetermined temperature, and closes when the temperature is above a predetermined temperature. If air remains in the first inlet pipe 26, the temperature inside the first inlet pipe 26 becomes lower than a predetermined temperature, and the air vent valve 30 opens. Then, the air in the first inlet pipe 26 is discharged to the outside of the first inlet pipe 26 through the air vent valve 30. When the air is discharged, the temperature of the steam rises and approaches the saturation temperature, and the air vent valve 30 is closed. Accordingly, the air vent valve 30 can bring the temperature of the steam flowing through the first inlet pipe 26 to the saturation temperature.

FIG. 2 is a front view showing a configuration example of the first heat exchanger 24. 3 is a left side view in the III direction of FIG. FIG. 4 is a right side view in the IV direction of FIG.

The first heat exchanger 24 is configured to include a sending side header 32, a sending side header 34, and a plurality of heat exchange tubes 36. The sending-in header 32 and the sending-out header 34 are formed, for example, in a flat box shape having a space inside. The sending-side header 32 and the sending-side header 34 are arranged to face each other.

The heat exchange tube 36 is formed in a straight tube shape. One end of the heat exchange pipe 36 communicates with the inlet header 32. That is, one end of each of the plurality of heat exchange tubes 36 is collected by the inlet header 32. The other end of the heat exchange tube 36 communicates with the delivery-side header 34. That is, the other ends of the plurality of heat exchange tubes 36 are gathered by the sending-side header 34.

One inlet 38 is provided in the inlet header 32 on the opposite side of the heat exchange tube 36. The inlet 38 is provided, for example, on the relatively upper side of the inlet header 32. The first inlet pipe 26 communicates with the inlet 38.

One delivery port 40 is provided on the delivery header 34 on the opposite side of the heat exchange tube 36. The delivery port 40 is provided, for example, on the relatively lower side of the delivery-side header 34. The first delivery pipe 42 communicates with the delivery port 40.

The plurality of heat exchange tubes 36 are arranged in the height direction of the first heat exchanger 24 (vertical direction in FIGS. 3 and 4) and the depth direction of the first heat exchanger 24 (horizontal direction in FIGS. 3 and 4), respectively. Are arranged in parallel. The plurality of heat exchange tubes 36 are arranged substantially evenly spaced so that air, which is an example of the object to be heated, can pass through the gaps between the heat exchange tubes 36. The number and arrangement of the heat exchange tubes 36 are not limited to the examples shown in FIGS. The object to be heated is not limited to air, but may be water, for example.

On the outer peripheral surface of the heat exchange tube 36, fins 44 projecting outward from the outer peripheral surface are provided. The fins 44 are provided spirally, for example, in the longitudinal direction of the heat exchange tube 36. The fins 44 are provided so as not to contact the fins 44 of the adjacent heat exchange tubes 36. The fins 44 are provided to increase the surface area (heat transfer surface) of the heat exchange tube 36.

The first heat exchanger 24 performs heat exchange between the steam supplied from the steam supply source 20 through the first inlet pipe 26 and the object to be heated. Specifically, the steam supplied through the first inlet pipe 26 first enters the inlet header 32 through the inlet 38. After that, the steam of the inlet header 32 is distributed and sent to the plurality of heat exchange tubes 36. The steam flowing in the heat exchange pipe 36 exchanges heat with the object to be heated (for example, air) that contacts the outer peripheral surface of the heat exchange pipe 36 and the fins 44. When the latent heat of the steam flowing through the heat exchange tube 36 is used to heat the object to be heated (when the latent heat of the steam moves to the object to be heated), the temperature of the steam is lowered and the steam is condensed, so that the heat exchange tube 36 Drain (water) is generated inside.

The configuration of the first heat exchanger 24 is not limited to the configuration illustrated in FIGS. For example, the first heat exchanger 24 may be provided around the kiln-shaped structure, or may be provided inside a roller around which paper or the like is wound. The first heat exchanger 24 may be a shell-and-tube heat exchanger or a plate heat exchanger.

Here, as a comparative example, there is a steam heat exchange system in which the steam supplied to the first heat exchanger 24 is all used in the first heat exchanger 24. In the steam heat exchange system of this comparative example, since the latent heat of the steam supplied to the first heat exchanger 24 is all used for heating the object to be heated, the heat exchange pipe 36, the delivery-side header 34, and the delivery port 40 are connected to each other. No steam is delivered to the first delivery pipe 42 via the.

However, in the steam heat exchange system of this comparative example, the drain may be formed in a film shape on the inner surface of each heat exchange tube 36 and may stay in each heat exchange tube 36. When the drain forms a film and stays in the heat exchange tube 36, the heat transmission coefficient (ease of heat transfer to the object to be heated) in the first heat exchanger 24 decreases.

Therefore, in the steam heat exchange system 1 of the first embodiment, the amount of steam supplied to the first heat exchanger 24 per unit time (that is, the flow velocity of steam supplied to the first heat exchanger 24) is compared with the above-described comparison. Larger than the example steam heat exchange system. In other words, in the steam heat exchange system 1 of the first embodiment, the steam used in the first heat exchanger 24 is supplied to the inlet 38 of the first heat exchanger 24 in an amount larger than the steam amount per unit time. To be done.

Below, the amount of steam per unit time when the first heat exchanger 24 uses all of the steam supplied to the first heat exchanger 24 is called the rated amount of steam. For example, in the steam heat exchange system 1 of the first embodiment, when the rated steam amount is 100%, the inlet 38 of the first heat exchanger 24 has a steam amount of 101% to 110% per unit time. Is supplied.

In the steam heat exchange system 1 of the first embodiment, the flow velocity of steam in the heat exchange pipe 36 is higher than that in the comparative example described above. Therefore, the drain generated in the heat exchange pipe 36 is swept to the downstream side of the steam flow by the steam flowing in the heat exchange pipe 36.

Then, in the steam heat exchange system 1 of the first embodiment, since the steam having the steam amount larger than the steam amount used in the first heat exchanger 24 is supplied to the first heat exchanger 24, the first heat exchange is performed. The drain generated in the reactor 24 is sent out from the outlet 40 together with the (excessive) steam not used in the first heat exchanger 24. For example, in the steam heat exchange system 1 of the first embodiment, the steam having a steam amount of 1% to 10% with respect to the rated steam amount is sent from the outlet 40 of the first heat exchanger 24.

That is, the first heat exchanger 24 sends the drain generated by the heat exchange out of the first heat exchanger 24 together with a part of the steam supplied from the steam supply source 20 to the first heat exchanger 24. In the steam heat exchange system 1 of the first embodiment, the drain generated by heat exchange is sent to the outside of the first heat exchanger 24, so that the drain does not stay in a film form on the inner surface of the heat exchange pipe 36. As a result, in the steam heat exchange system 1 of the first embodiment, it is possible to prevent a decrease in the heat transmission coefficient in the first heat exchanger 24, as compared with the comparative example described above.

Referring back to FIG. 1, in the steam heat exchange system 1 according to the first embodiment, the (excessive) steam that is not used in the first heat exchanger 24 is used in the low-pressure second heat exchanger 50. I am trying.

The second heat exchanger 50 has the same configuration as that of the first heat exchanger 24 described with reference to FIGS. 2 to 4, except for the pressure of the steam to be supplied and the supply source. The second heat exchanger 50 exchanges heat between the supplied steam and the object to be heated (air).

The first delivery pipe 42 communicates with the separator 60. A first drain recovery pipe 62 that extends vertically below the first delivery pipe 42 is connected to the middle of the first delivery pipe 42. The first drain 14 is provided with the first drain recovery pipe 62. The first trap 14 collects the drain that has entered the first drain recovery pipe 62. The drain collected in the first trap 14 is collected in the water supply tank 10. The first drain recovery pipe 62 and the first trap 14 may be omitted.

Since the flow velocity of the steam sent from the first heat exchanger 24 is high, a part of the drain is sent to the separator 60 together with the steam without entering the first drain recovery pipe 62. That is, the separator 60 is supplied with the (excess) steam and drain that were not used in the first heat exchanger 24.

The separator 60 is composed of, for example, a pipe having a cross-sectional area larger than that of the first delivery pipe 42. The second drain recovery pipe 64 communicates vertically below the separator 60. The steam flow pipe (steam flow section) 66 communicates vertically above the separator 60.

The separator 60 separates the steam supplied through the first delivery pipe 42 from the drain. Specifically, when the steam and the drain enter the separator 60, the drain moves vertically downward by its own weight and enters the second drain recovery pipe 64. On the other hand, since the steam is relatively lighter than the drain, it mainly diffuses vertically upward and enters the steam flow pipe 66.

The second drain recovery pipe 64 is provided with the second trap 16. The second trap 16 collects the drain separated by the separator 60 and entering the second drain recovery pipe 64. The drain collected in the second trap 16 is collected in the water supply tank 10.

The thermometer 68 is provided between the separator 60 and the second trap 16 in the second drain recovery pipe 64. The thermometer 68 measures the temperature inside the second drain recovery pipe 64. That is, the thermometer 68 measures the temperature of the drain (drain separated by the separator 60) sent from the first heat exchanger 24.

In the first heat exchanger 24, drain is evenly generated from upstream to downstream. The drain generated on the upstream side gradually moves to the downstream side, but stays in the first heat exchanger 24 for a long time. When the residence time in the first heat exchanger 24 is long, the temperature of the drain drops. Then, the more the drain is accumulated in the first heat exchanger 24, the larger the decrease range of the temperature of the drain when it is delivered from the first heat exchanger 24. Therefore, in the steam heat exchange system 1, the temperature of the drain sent from the first heat exchanger 24 is detected and the discharge of the drain in the first heat exchanger 24 is controlled.

The drain discharged from the first heat exchanger 24 moves through the first delivery pipe 42, the separator 60, and the second drain recovery pipe 64, and is collected by the second trap 16. Since the temperature of the drain tends to decrease as time passes after the vapor is condensed and becomes drain, the temperature decreases as it goes downstream in the path along which the drain moves. As the temperature decreases, the influence of the measurement error of the thermometer 68 at the time of deriving the temperature difference from the saturation temperature decreases, and the temperature difference can be accurately derived. Therefore, the thermometer 68 is provided in the second drain recovery pipe 64 located on the downstream side.

The position at which the thermometer 68 is provided is not limited to the position between the separator 60 and the second trap 16 in the second drain recovery pipe 64. For example, when it is not necessary to precisely measure the temperature of the drain, the thermometer 68 may be provided in the separator 60 or the first delivery pipe 42. That is, the thermometer 68 is provided in the primary-side drain flow path that is on the downstream side of the first heat exchanger 24 and on the upstream side of the second trap 16 in the path through which the drain flows. The temperature of the drain flowing through the path may be detected.

The steam flow pipe 66 communicates with the inlet 54 of the second heat exchanger 50. The steam flow pipe 66 guides the steam separated in the separator 60 (steam not used in the first heat exchanger 24) to the second heat exchanger 50.

A pressure adjusting valve 70 is provided on the steam flow pipe 66. The pressure adjusting valve 70 changes the opening degree of the flow path in the steam flow pipe 66.

The pressure gauge 72 is provided in the separator 60. The pressure gauge 72 is connected to the separator 60 via a siphon tube 73. The pressure gauge 72 detects the pressure of the vapor in the separator 60.

The position where the pressure gauge 72 is provided is not limited to the separator 60. For example, the pressure gauge 72 may be provided in the first delivery pipe 42, or may be provided in the steam flow pipe 66 between the separator 60 and the pressure control valve 70. That is, the pressure gauge 72 is provided in the primary-side steam distribution path, which is the downstream side of the first heat exchanger 24 and the upstream side of the pressure regulating valve 70 in the path through which the steam flows, and the primary-side steam distribution path. You may detect the pressure of the steam which circulates through.

An orifice 74 is provided between the pressure regulating valve 70 and the second heat exchanger 50 in the steam flow pipe 66. The orifice 74 is formed, for example, in an annular shape, and narrows the cross-sectional area of a predetermined section of the flow path in the steam flow pipe 66. The orifice 74 has a predetermined flow velocity so that the flow velocity of the steam in the first delivery pipe 42 and the flow velocity of the steam in the vapor flow pipe 66 between the separator 60 and the orifice 74 do not become too high. suppress. The predetermined flow rate is, for example, a flow rate when 10% of the rated amount of steam flows into the separator 60. Further, the orifice 74 lowers the pressure of steam on the downstream side of the steam flow with respect to the orifice 74 as compared with the pressure of steam on the upstream side of the steam flow with respect to the orifice 74.

A check valve 76 is provided in the steam flow pipe 66 between the orifice 74 and the second heat exchanger 50. The check valve 76 permits the flow in the direction from the separator 60 to the second heat exchanger 50, and blocks the flow in the direction from the second heat exchanger 50 to the separator 60.

An air vent valve 78 is provided between the separator 60 and the pressure control valve 70 in the steam flow pipe 66. The air vent valve 78 is opened while the temperature inside the steam flow pipe 66 is below or below a predetermined temperature, and is closed when the temperature is above a predetermined temperature. The air vent valve 78 discharges the air remaining in the steam flow pipe 66 to the outside of the steam flow pipe 66, so that the temperature of the steam flowing through the steam flow pipe 66 can reach the saturation temperature.

The control unit 80 is composed of a semiconductor integrated circuit including a central processing unit (CPU), a non-volatile memory, a volatile memory and the like. The control unit 80, based on the pressure detected by the pressure gauge 72, opens (or closes) the pressure adjustment valve 70 so that the pressure in the separator 60 (pressure of the pressure gauge 72) becomes substantially constant. To control. As a result, the pressure between the orifice 74 in the steam flow pipe 66 and the second heat exchanger 50 is adjusted to a predetermined pressure.

When the pressure of the pressure gauge 72 rises, the pressure gradient in the first heat exchanger 24 becomes smaller, the amount of steam sent from the first heat exchanger 24 decreases, and the drain is discharged from the first heat exchanger 24. It will be difficult. Therefore, the control unit 80 increases the opening degree of the pressure adjusting valve 70 when the pressure of the pressure gauge 72 is about to change in the increasing direction. When the opening degree of the pressure adjustment valve 70 increases, the pressure on the downstream side of the first heat exchanger 24 decreases, the pressure gradient in the first heat exchanger 24 increases, and the drainage is discharged from the first heat exchanger 24. It is easy to be done.

Further, when the pressure of the pressure gauge 72 decreases, drainage is easily discharged from the first heat exchanger 24, but excessive steam is sent out from the first heat exchanger 24. For this reason, the control unit 80 reduces the opening degree of the pressure adjusting valve 70 when the pressure of the pressure gauge 72 is about to decrease. When the opening degree of the pressure regulating valve 70 decreases, the pressure on the downstream side of the first heat exchanger 24 rises, and it is possible to suppress the excessive delivery of steam from the first heat exchanger 24.

Further, the control unit 80 may control the opening degree (or closing degree) of the pressure adjusting valve 70 based on the temperature detected by the thermometer 68.

When drainage collects in the first heat exchanger 24, the temperature detected by the thermometer 68 lowers and the temperature difference from the saturation temperature increases. Therefore, the control unit 80 increases the opening degree of the pressure adjusting valve 70 when the temperature of the thermometer 68 decreases (when the temperature difference from the saturation temperature increases). When the opening degree of the pressure adjustment valve 70 increases, the pressure on the downstream side of the first heat exchanger 24 decreases, and the drain is easily discharged from the first heat exchanger 24.

Further, when the drain is not much accumulated in the first heat exchanger 24, the temperature detected by the thermometer 68 rises and the temperature difference from the saturation temperature becomes small. Therefore, when the temperature of the thermometer 68 rises (when the temperature difference from the saturation temperature decreases), the controller 80 lowers the opening of the pressure adjusting valve 70. When the opening degree of the pressure regulating valve 70 decreases, the pressure on the downstream side of the first heat exchanger 24 rises, and it is possible to suppress the excessive delivery of steam from the first heat exchanger 24.

In the steam heat exchange system 1, one of the control of the pressure adjusting valve 70 based on the pressure of the pressure gauge 72 and the control of the pressure adjusting valve 70 based on the temperature of the thermometer 68 is the configuration of the first heat exchanger 24, etc. Selected by.

For example, in the first heat exchanger 24 where the distance through which steam flows (for example, the length of the heat exchange tube 36) is long, it takes time for the drain generated on the upstream side to move to the downstream side, and the temperature of the drain Is greatly reduced. In such a first heat exchanger 24 having a large drain temperature drop width, the temperature difference between the saturation temperature and the drain temperature is detected by detecting the temperature of the drain sent from the first heat exchanger 24. It can be derived accurately. Therefore, in the case of the first heat exchanger 24 in which the drain temperature decrease range is large, the steam heat exchange system 1 is configured to control the pressure adjustment valve 70 based on the temperature of the thermometer 68.

Further, in the first heat exchanger 24 where the distance through which the steam flows is short, the drain generated on the upstream side reaches the downstream side quickly, so that the temperature drop of the drain is small. In such a first heat exchanger 24 in which the drain temperature decrease range is small, it is difficult to accurately derive the temperature difference between the saturation temperature and the drain temperature. Therefore, in the case of the first heat exchanger 24 in which the decrease range of the drain temperature is small, it is not appropriate to control the pressure adjustment valve 70 based on the temperature of the thermometer 68.

However, when the distance through which the steam flows is short, the pressure inside the first heat exchanger 24 responds quickly to changes in the pressure outside the first heat exchanger 24. As such a first heat exchanger 24 having good pressure responsiveness, for example, there is a large volume surrounded by a heat transfer surface such as a kiln. In the case of the first heat exchanger 24 having good pressure responsiveness, the steam heat exchange system 1 is configured to control the pressure adjustment valve 70 based on the pressure of the pressure gauge 72. In this mode, the response delay of the control of the pressure regulating valve 70 can be suppressed.

The control unit 80 may control the pressure adjusting valve 70 based on both the pressure of the pressure gauge 72 and the temperature of the thermometer 68.

Further, a flow meter 82 is provided between the first pressure reducing valve 28 and the first heat exchanger 24 in the first inlet pipe 26. The flow meter 82 measures the flow rate of the steam introduced into the inlet 38 through the first inlet pipe 26. The flow rate measured by the flow meter 82 is used when adjusting the amount of steam supplied to the second heat exchanger 50 via the first heat exchanger 24.

Here, in the steam heat exchange system 1 of the first embodiment, the steam that is not used in the first heat exchanger 24 is used in the second heat exchanger 50, but the second heat is used through the first heat exchanger 24. The steam supplied to the heat exchanger 50 alone may not satisfy the amount of steam to be consumed by the second heat exchanger 50. Therefore, in addition to the steam being supplied to the second heat exchanger 50 via the first heat exchanger 24, the steam of the steam supply source 20 is decompressed and directly supplied.

Specifically, the second inlet pipe 52 communicates with the vapor supply source 20 in the first inlet pipe 26 and the first pressure reducing valve 28. The second inlet pipe 52 communicates with the check valve 76 in the steam flow pipe 66 and the second heat exchanger 50.

The second inlet pipe 52 is provided with a second pressure reducing valve 56. The second pressure reducing valve 56 lowers the pressure of the steam on the second heat exchanger 50 side than the pressure of the steam on the steam supply source 20 side with respect to the second pressure reducing valve 56 in the second inlet pipe 52. The steam decompressed by the second pressure reducing valve 56 is sent to the second heat exchanger 50. The second pressure reducing valve 56 has a pressure reduction width larger than that of the first pressure reducing valve 28. That is, the pressure of the steam supplied to the second heat exchanger 50 is lower than the pressure of the steam supplied to the first heat exchanger 24. The pressure of the steam supplied to the second heat exchanger 50 is, for example, 0.2 MPaG.

Further, the third drain recovery pipe 84 communicates with the outlet 86 of the second heat exchanger 50. A third trap 18 is provided in the third drain recovery pipe 84. The third trap 18 collects the drain generated in the second heat exchanger 50. The drain collected in the third trap 18 is collected in the water supply tank 10.

The pressure of the steam supplied to the second heat exchanger 50 may be lower than 0.2 MPaG. In this case, instead of the third trap 18, a steam driven pump may be provided in the third drain recovery pipe 84. The steam-driven pump collects the drain entering the third drain recovery pipe 84 and transfers it to the water supply tank 10 by using a steam of a system different from the steam system including the first heat exchanger 24 and the like.

Further, in the steam heat exchange system 1 of the first embodiment, the first heat exchanger 24 and the second heat exchanger 50 are operated in parallel. For example, the second heat exchanger 50 preheats the heated object, and the first heat exchanger 24 heats the preheated heated object.

FIG. 5: is a flowchart for demonstrating the operation at the time of starting in the steam heat exchange system 1 of 1st Embodiment. The process shown in the flowchart of FIG. 5 is performed by an administrator or a user of the steam heat exchange system 1 (hereinafter referred to as an administrator).

First, the administrator or the like closes the pressure regulating valve 70 (S100), and in this state, causes the steam supply source 20 to supply steam to the first heat exchanger 24 (S110). In this state, since there is almost no pressure difference between the inlet 38 and the outlet 40 of the first heat exchanger 24, the steam supplied from the steam supply source 20 to the first heat exchanger 24 is the first heat exchanger. All used in 24.

Next, in this state, the administrator or the like visually confirms the flow rate indicated by the flow meter 82 (S120), and determines the confirmed flow rate as the rated vapor amount (S130).

Next, the manager or the like determines the target amount of steam to be fed into the inlet 38 of the first heat exchanger 24 (target fed steam amount) based on the determined rated vapor amount (S140). For example, the manager or the like determines 110% of the rated steam amount as the target steam input amount. Note that the present invention is not limited to the mode in which 110% of the rated steam amount is determined as the target incoming steam amount. For example, an administrator or the like may determine the target amount of steam to be fed in from the range of 101% of the rated steam amount to 110% of the rated steam amount.

Next, the administrator or the like opens the pressure adjusting valve 70 at an arbitrary opening (S150). When the pressure regulating valve 70 opens, the pressure of the outlet 40 of the first heat exchanger 24 decreases, and the pressure of the inlet 38 of the first heat exchanger 24 decreases accordingly.

At this time, the steam supply source 20 is controlled so that the pressure of the steam supplied to the first heat exchanger 24 is constant. Therefore, the steam supply source 20 increases the pressure of the steam to be output in order to return the pressure of the inlet port 38 of the first heat exchanger 24 to the pressure before the decrease.

As a result, the steam supply source 20 supplies a larger amount of steam to the first heat exchanger 24 than the flow rate before opening the pressure regulating valve 70.

Next, the administrator or the like sets the set value of the pressure gauge 72 in the control unit 80 (S160). When the setting value of the pressure gauge 72 is set, the control unit 80 causes the opening degree of the pressure adjusting valve 70 to be based on the setting value. The operation of the control unit 80 will be described later in detail.

Next, the administrator or the like visually confirms the flow rate of the steam indicated by the flow meter 82 (S170), and determines whether the flow rate of the steam matches the target feed-in steam amount (S180). When the flow rate of steam does not match the target steam input amount (NO in S180), the administrator or the like changes the setting value of the pressure gauge 72 and resets it (S160).

On the other hand, when the flow rate of steam matches the target amount of steam to be fed (YES in S180), the administrator or the like ends the series of operations. In this way, the administrator or the like finds the set value of the pressure gauge 72 by trial and error so that the flow rate of the steam indicated by the flow meter 82 becomes the target amount of steam to be fed.

FIG. 6 is a flowchart illustrating the operation of the control unit 80 based on the pressure of the pressure gauge 72. First, the control unit 80 determines whether or not there is an instruction to stop the steam heat exchange system 1 (S200). The control part 80 complete|finishes a series of processes, when the stop instruction|indication of the steam heat exchange system 1 is received (YES in S200).

On the other hand, when there is no instruction to stop the steam heat exchange system 1 (NO in S200), the control unit 80 determines whether a predetermined time has passed (S210). When the predetermined time has not elapsed (NO in S210), the control unit 80 returns to the process of step S200.

On the other hand, when the predetermined time has elapsed (YES in S210), the control unit 80 acquires the pressure indicated by the pressure gauge 72 (S220). Next, the control unit 80 derives the pressure difference between the acquired pressure of the pressure gauge 72 and the set value of the pressure gauge 72 (S230). Next, the control unit 80 derives the target opening degree of the pressure regulating valve 70 such that the derived pressure difference becomes zero (S240). Then, the control unit 80 opens the pressure adjusting valve 70 at the derived target opening degree (S250), and returns to the process of step S200. In this way, the control unit 80 controls the opening degree of the pressure adjusting valve 70 so that the pressure of the pressure gauge 72 reaches the set value. As a result, in the steam heat exchange system 1, the amount of steam supplied to the second heat exchanger 50 via the first heat exchanger 24 is controlled to a flow rate based on the target incoming steam amount.

FIG. 7 is a flowchart illustrating the operation of the control unit 80 based on the temperature of the thermometer 68. The flowchart of FIG. 7 differs from the flowchart of FIG. 6 in that steps S320 to S340 are performed instead of steps S220 to S240. Therefore, a description of steps that are the same as the steps of the flowchart of FIG. 6 will be omitted, and different steps will be described in detail.

When the predetermined time has passed (YES in S210), the control unit 80 acquires the temperature of the thermometer 68 (S320). Next, the control unit 80 derives the temperature difference between the acquired temperature of the thermometer 68 and the saturated temperature of the steam (S330). Next, the control unit 80 derives the target opening degree of the pressure regulating valve 70 based on the derived temperature difference (S340). Then, the control unit 80 opens the pressure adjustment valve 70 at the derived target opening degree (S250).

Here, when the drain collects in the primary side drain flow path from the first heat exchanger 24 to the second trap 16, the temperature inside the second drain recovery pipe 64 in which the thermometer 68 is installed becomes saturated. Decreases with temperature. That is, in this case, the temperature difference derived in step S330 becomes large.

The control unit 80 increases the target opening degree if the derived temperature difference is larger than the temperature difference derived in the previous control cycle. Then, the amount of steam delivered from the delivery port 40 of the first heat exchanger 24 increases. As a result, the drain in the primary side drain flow path is easily washed away by the steam, and drain discharge is promoted.

When the drain in the primary side drain flow path is washed away and reduced, the temperature in the second drain recovery pipe 64 approaches the saturation temperature. That is, in this case, the temperature difference derived in step S330 becomes small.

If the derived temperature difference is smaller than the temperature difference derived in the previous control cycle, the controller 80 reduces the target opening degree. Then, the amount of steam delivered from the delivery port 40 of the first heat exchanger 24 decreases. Thereby, it is possible to prevent the steam from being excessively delivered from the delivery port 40.

As described above, in the steam heat exchange system 1 of the first embodiment, the drain generated in the heat exchange pipe 36 of the first heat exchanger 24 is sent to the outside of the first heat exchanger 24 by the steam, and The steam sent out of the first heat exchanger 24 is used in the second heat exchanger 50.

Therefore, according to the steam heat exchange system 1 of the first embodiment, the steam heat exchange system 1 as a whole can suppress the loss of steam and prevent the reduction of the heat transmission coefficient in the first heat exchanger 24. ..

Further, in the steam heat exchange system 1 of the first embodiment, an orifice 74 is provided in the middle of the steam flow pipe 66 so that the flow velocity of steam between the first heat exchanger 24 and the orifice 74 does not become too high. ing. As a result, in the steam heat exchange system 1 of the first embodiment, it is possible to prevent the steam not used in the first heat exchanger 24 from increasing more than necessary. In other words, in the steam heat exchange system 1 of the first embodiment, an appropriate amount of steam (specifically, 1% to 10% of the rated steam amount) for sending drain from the first heat exchanger 24 is supplied. It can be delivered from the first heat exchanger 24.

The second heat exchanger 50 is supplied with steam not used in the first heat exchanger 24, and is also directly supplied with steam from the steam supply source 20 via the second pressure reducing valve 56. It was However, it suffices that the steam not used in the first heat exchanger 24 is supplied to the second heat exchanger 50, and the steam is directly supplied from the steam supply source 20 via the second pressure reducing valve 56. You don't have to.

When the second heat exchanger 50 is supplemented with steam through the second pressure reducing valve 56, the pressure of the steam in the second heat exchanger 50 is compared with the pressure of the steam in the first heat exchanger 24. Make it small enough.

Further, in the steam heat exchange system 1, the positions of the air vent valves 30 and 78 are not limited to the positions of the first inlet pipe 26 and the steam flow pipe 66. Further, the number of air vent valves is not limited to two, and may be one or three or more. The greater the number of air vent valves, the more quickly air can be vented.

(Second embodiment)
FIG. 8 is a schematic diagram showing the configuration of the steam heat exchange system 100 according to the second embodiment. In the first embodiment, the pressure gauge 72 is provided between the first heat exchanger 24 and the pressure adjusting valve 70 (on the primary side of the pressure adjusting valve 70). On the other hand, in the steam heat exchange system 100 of the second embodiment, the pressure gauge 72 is provided on the secondary side of the pressure regulating valve 70. In the steam heat exchange system 100, the thermometer 68 is omitted.

In the steam heat exchange system 100, the pressure gauge 72 is provided between the pressure regulating valve 70 and the orifice 74 in the steam flow pipe 66. The pressure gauge 72 is connected to the steam flow pipe 66 via a siphon pipe 73. The pressure gauge 72 detects the pressure of the steam in the steam flow pipe 66 between the pressure regulating valve 70 and the orifice 74.

The control unit 80 of the second embodiment controls the pressure control valve 70 so that the pressure of the steam (pressure of the pressure gauge 72) in the steam flow pipe 66 between the pressure control valve 70 and the orifice 74 becomes substantially constant. Control the opening. The control unit 80 increases the opening of the pressure adjusting valve 70 when the pressure of the pressure gauge 72 is going to decrease, and increases the opening of the pressure adjusting valve 70 when the pressure of the pressure gauge 72 is going to increase. The predetermined pressure is maintained by decreasing the opening.

Therefore, in the steam heat exchange system 100 of the second embodiment, similarly to the first embodiment, the steam heat exchange system 100 as a whole suppresses the loss of steam and prevents the decrease of the heat transmission coefficient in the first heat exchanger 24. It becomes possible to do.

The pressure gauge 72 may be provided between the orifice 74 in the steam flow pipe 66 and the second heat exchanger 50. In this case, the control unit 80 may control the opening degree of the pressure adjusting valve 70 based on the pressure of the steam in the steam flow pipe 66 between the orifice 74 and the second heat exchanger 50.

Further, the control unit 80 controls the opening degree of the pressure adjusting valve 70 based on the pressure of the pressure gauge 72. However, the control unit 80 may acquire the flow rate indicated by the flow meter 82 and control the opening degree of the pressure adjustment valve 70 based on the flow rate. In this case, the control unit 80 does not have to acquire the pressure of the pressure gauge 72.

Further, in the steam heat exchange system 100, a pressure reducing valve that does not require signal transmission/reception may be provided between the separator 60 and the orifice 74 instead of the pressure adjusting valve 70, the pressure gauge 72, and the control unit 80. ..

(Third Embodiment)
FIG. 9 is a schematic diagram showing the configuration of the steam heat exchange system 200 according to the third embodiment. The steam heat exchange system 200 of the third embodiment differs from that of the second embodiment in the configuration of controlling the pressure of steam between the separator 60 and the second heat exchanger 50. Further, in the steam heat exchange system 200 of the third embodiment, the first heat exchanger 24 and the second heat exchanger 50 can be operated individually.

In the second embodiment, the steam flow pipe 66 is provided with an air vent valve 78, an electric valve (motor valve) 202, a throttle valve 204, an orifice 74, a pressure gauge 72, and a check valve 76 in order from the separator 60 side. ing. In other words, the orifice 74 is provided in the steam flow pipe 66 between the separator 60 and the second heat exchanger 50. The motor operated valve 202 is provided between the separator 60 and the orifice 74 in the steam flow pipe 66. The throttle valve 204 is provided between the electric valve 202 and the orifice 74 in the steam flow pipe 66. The air vent valve 78 is provided between the separator 60 and the electric valve 202 in the steam flow pipe 66. The pressure gauge 72 is provided between the orifice 74 in the steam flow pipe 66 and the second heat exchanger 50. The check valve 76 is provided in the steam flow pipe 66 between the pressure gauge 72 and the second heat exchanger 50.

The motor-operated valve 202 switches between opening and closing (on or off) of the flow path in the steam flow pipe 66. The throttle valve 204 changes the opening of the flow path in the steam flow pipe 66. The opening degree of the throttle valve 204 can be manually changed. For example, the administrator visually confirms the flow rate indicated by the flow meter 82, and manually adjusts the opening degree of the throttle valve 204 so that the flow rate becomes 110% of the rated vapor amount. The pressure gauge 72 detects the pressure of the steam flowing through the steam flow pipe 66 between the orifice 74 and the second heat exchanger 50. The orifice 74 is omitted when the throttle valve 204 can function as the orifice 74 (when the flow rate of steam flowing through the steam flow pipe 66 can be sufficiently suppressed by the throttle valve 204). Good.

The control unit 80 controls opening/closing (ON or OFF) of the electric valve 202 based on the pressure detected by the pressure gauge 72. Specifically, the control unit 80 closes the electric valve 202 when the pressure detected by the pressure gauge 72 exceeds a predetermined first threshold value. When the electrically operated valve 202 is closed, steam does not flow to the second heat exchanger 50 side of the electrically operated valve 202. On the other hand, the control unit 80 opens the motor-operated valve 202 when the pressure detected by the pressure gauge 72 falls below a predetermined second threshold value that is smaller than the first threshold value. When the motor-operated valve 202 is opened, the flow rate of steam between the separator 60 and the orifice 74 is based on the opening degree of the throttle valve 204.

FIG. 10 is an explanatory diagram for explaining the operation of the steam heat exchange system 200 of the third embodiment. For example, it is assumed that both the first heat exchanger 24 and the second heat exchanger 50 are operating during the time between time T0 and time T1. In this case, the pressure of the pressure gauge 72 is less than or equal to the second threshold value. Therefore, the control unit 80 maintains the motor-operated valve 202 in the open state.

From this state, at time T1, it is assumed that the second heat exchanger 50 stops while the first heat exchanger 24 maintains the operation. Then, although the steam continues to be emitted from the outlet 40 of the first heat exchanger 24, the steam is no longer consumed in the second heat exchanger 50, so that the pressure of the steam in the steam flow pipe 66 increases. That is, in this case, the pressure of the inlet 54 of the second heat exchanger 50 increases.

Then, when the pressure of the pressure gauge 72 (the pressure of the steam between the orifice 74 and the second heat exchanger 50) exceeds the first threshold value at the time T2, the control unit 80 closes the electric valve 202. When the motor-operated valve 202 is closed, an increase in the pressure of steam between the motor-operated valve 202 and the second heat exchanger 50 is suppressed.

After that, it is assumed that the second heat exchanger 50 operates again at time T3. At this time, the steam accumulated between the motor-operated valve 202 and the second heat exchanger 50 is consumed in the second heat exchanger 50, so that the pressure of the pressure gauge 72 decreases.

Then, when the pressure of the pressure gauge 72 falls below the second threshold value at time T4, the control unit 80 opens the electric valve 202. When the motor-operated valve 202 is opened, steam is supplied from the first heat exchanger 24 to the second heat exchanger 50 through the steam flow pipe 66, so that the pressure gauge 72 is prevented from lowering the pressure. After that, the control unit 80 maintains the electrically operated valve 202 in the open state until the pressure of the pressure gauge 72 exceeds the first threshold value.

As described above, the steam heat exchange system 200 of the third embodiment, like the first embodiment, suppresses the loss of steam in the steam heat exchange system 200 as a whole, and reduces the heat transmission coefficient of the first heat exchanger 24. It is possible to prevent the decrease.

In addition, according to the steam heat exchange system 200 of the third embodiment, even if the operation of the second heat exchanger 50 is stopped alone, the pressure of the steam at the inlet 54 of the second heat exchanger 50 becomes unnecessarily high. It is possible to prevent rising. As a result, damage to the second heat exchanger 50 can be prevented.

In addition, the first threshold value and the second threshold value that are the reference for opening and closing the motor-operated valve 202 constitute so-called hysteresis. For this reason, in the steam heat exchange system 200 of the third embodiment, the motor-operated valve 202 opens and closes more frequently than necessary (in other words, hunting), as compared with an aspect in which the first threshold value and the second threshold value match. Can be suppressed.

The pressure gauge 72 was provided between the orifice 74 in the steam flow pipe 66 and the second heat exchanger 50. However, the pressure gauge 72 may be provided between the electric valve 202 and the orifice 74 in the steam flow pipe 66. In this case, the control unit 80 may control the opening/closing of the electric valve 202 and the opening degree of the throttle valve 204 based on the pressure of the steam in the steam flow pipe 66 between the electric valve 202 and the orifice 74. Further, the pressure gauge 72 may be provided in the first delivery pipe 42, may be provided in the separator 60, or may be provided between the separator 60 and the motor-operated valve 202 in the steam flow pipe 66. Good.

(Fourth Embodiment)
FIG. 11 is a schematic diagram showing the configuration of the steam heat exchange system 300 according to the fourth embodiment. The steam heat exchange system 1 of the first embodiment collects the drain collected in the first trap 14 and the second trap 16 in the water supply tank 10. On the other hand, in the steam heat exchange system 300 of the fourth embodiment, flash steam is generated from the drain collected in the first trap 14 and the second trap 16, and the steam not used in the first heat exchanger 24 is generated. In addition, flash steam is also supplied to the second heat exchanger 50.

The first trap 14 is connected to the flash tank 310 via a check valve 302. The check valve 302 permits the flow in the direction from the first trap 14 to the flash tank 310, and blocks the flow from the flash tank 310 to the first trap 14.

The second trap 16 is connected to the flash tank 310 via a check valve 304. The check valve 304 permits the flow in the direction from the second trap 16 to the flash tank 310, and blocks the flow from the flash tank 310 to the second trap 16.

The flash tank 310 is, for example, formed in a tubular shape having an internal space. The internal pressure of the flash tank 310 is set to the atmospheric pressure or lower (atmospheric pressure or negative pressure). One end of the second inlet pipe 312 communicates vertically above the flash tank 310, and the other end communicates with the inlet 54 of the second heat exchanger 50.

The steam flow pipe 66 communicates with the second inlet pipe 312. The steam flow pipe 66 is provided with an air vent valve 78, a pressure adjusting valve 70, an orifice 74, and a check valve 76, as in the first embodiment.

The third drain recovery pipe 84 is provided between the outlet 86 of the second heat exchanger 50 and the steam driven pump 314. One end of the fourth drain recovery pipe 316 communicates vertically below the flash tank 310, and the other end communicates with the third drain recovery pipe 84.

The drain trapped by the first trap 14 and the second trap 16 has a high pressure of 100 degrees or more. When this drain enters the flash tank 310, the drain becomes 100 degrees at atmospheric pressure, and the latent heat of the pressure difference generated due to the pressure drop is used to convert a part of the drain into steam (flash steam).

In the flash tank 310, the drain that has not changed to steam (drain of 100 degrees at atmospheric pressure) moves vertically downward by its own weight and enters the fourth drain recovery pipe 316. On the other hand, since the generated steam (flash steam) is relatively lighter than the drain, it mainly diffuses vertically upward and enters the second inlet pipe 312. The steam that has entered the second inlet pipe 312 is sent to the second heat exchanger 50.

Further, the steam not used in the first heat exchanger 24 is separated by the separator 60 and sent to the second heat exchanger 50 through the steam flow pipe 66 and the second inlet pipe 312.

That is, the steam not used in the first heat exchanger 24 and the steam generated in the flash tank 310 (flash steam) are supplied to the second heat exchanger 50. Therefore, the second heat exchanger 50 performs heat exchange using the steam not used in the first heat exchanger 24 and the steam generated in the flash tank 310.

The steam driven pump 314 is supplied with steam in a system different from the steam system including the first heat exchanger 24 and the like. The steam-driven pump 314 collects the drain generated in the second heat exchanger 50 and the drain entering the fourth drain recovery pipe 316 from the flash tank 310 and transfers the drain to the water supply tank 10 by the steam of the separate system.

As described above, the steam heat exchange system 300 of the fourth embodiment, like the first embodiment, suppresses the loss of steam in the steam heat exchange system 300 as a whole, and reduces the heat transmission coefficient of the first heat exchanger 24. It is possible to prevent the decrease.

In addition, in the steam heat exchange system 300 of the fourth embodiment, the heat exchange in the second heat exchanger 50 is performed using both the steam sent from the first heat exchanger 24 and the drain. Therefore, in the steam heat exchange system 300 of the fourth embodiment, the thermal efficiency of the entire steam heat exchange system 300 can be further increased.

In the steam heat exchange system 300 of the fourth embodiment, the steam separated by the separator 60 was directly supplied to the second heat exchanger 50 without passing through the flash tank 310. However, the steam separated by the separator 60 may be supplied to the second heat exchanger 50 via the flash tank 310. That is, the steam flow pipe 66 may communicate with the flash tank 310.

Further, in the steam heat exchange system 300 of the fourth embodiment, the control of the pressure regulating valve 70 has the same configuration as that of the first embodiment, but may have the same configuration as that of the second and third embodiments. Good.

Although the embodiments of the present invention have been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to such embodiments. It is obvious to those skilled in the art that various changes or modifications can be conceived within the scope described in the claims, and naturally, they also belong to the technical scope of the present invention. Understood.

For example, in each of the above embodiments, the first heat exchanger 24 that uses high-pressure steam and the second heat exchanger 50 that uses low-pressure steam are configured in two stages. However, the configuration is not limited to the two-stage configuration of the first heat exchanger 24 and the second heat exchanger 50. For example, a steam heat exchange system includes three stages, a high-pressure heat exchanger that uses high-pressure steam, a medium-pressure heat exchanger that uses medium-pressure steam, and a low-pressure heat exchanger that uses low-pressure steam. May be done.

In this case, the steam not used in the high pressure heat exchanger may be supplied to the medium pressure heat exchanger, and the steam not used in the medium pressure heat exchanger may be supplied to the low pressure heat exchanger in a cascade connection. .. In addition, the steam not used in the high pressure heat exchanger is supplied to the medium pressure heat exchanger, and the steam not used in the high pressure heat exchanger is further reduced in pressure from the middle pressure to be supplied to the low pressure heat exchanger. Distribution connection may be used. Also in these configurations, it is possible to prevent a decrease in the heat transmission coefficient in the high pressure heat exchanger while suppressing the loss of steam in the entire steam heat exchange system.

Further, in each of the above-described embodiments, the pressure of the steam supplied to the second heat exchanger 50 was lower than the pressure of the steam supplied to the first heat exchanger 24. However, when the second heat exchanger 50 is not directly supplemented with steam from the steam supply source 20, steam having a pressure equal to the pressure of steam supplied to the first heat exchanger 24 is supplied from the first heat exchanger. It may be supplied to the second heat exchanger, or steam having a pressure higher than that of the steam supplied to the first heat exchanger 24 may be supplied from the first heat exchanger to the second heat exchanger via a compressor or the like. May be supplied to the container.

INDUSTRIAL APPLICATION This invention can be utilized for a steam heat exchange system.

1, 100, 200, 300 Steam heat exchange system 20 Steam supply source 24 First heat exchanger 40 Outlet 50 Second heat exchanger 60 Separator 66 Steam distribution pipe (steam distribution section)
70 Pressure Control Valve 72 Pressure Gauge 74 Orifice 80 Control Unit 202 Electric Valve 310 Flash Tank

Claims (7)

A first heat exchanger that performs heat exchange between the steam supplied from the steam supply source and the object to be heated, and sends out the drain generated by the heat exchange from the outlet together with a part of the steam supplied from the steam supply source. When,
A separator for separating drain and steam supplied from the outlet of the first heat exchanger;
A second heat exchanger to which the steam separated by the separator is supplied and which performs heat exchange between the supplied steam and the object to be heated,
A steam heat exchange system. A steam flow section for guiding the steam separated by the separator to the second heat exchanger,
An orifice that is provided in the steam flow unit and narrows the cross-sectional area of a predetermined section of the flow path in the steam flow unit,
The steam heat exchange system according to claim 1, further comprising: A pressure adjusting valve that is provided between the separator and the orifice in the steam flow unit and that changes the opening degree of the flow path in the steam flow unit,
The pressure of steam flowing through the primary-side steam distribution path, which is provided in the primary-side steam distribution path that is downstream of the first heat exchanger and upstream of the pressure control valve in the path through which steam flows. With a pressure gauge to detect
A control unit for controlling the opening of the pressure regulating valve based on the pressure of the pressure gauge,
The steam heat exchange system according to claim 2, further comprising: A pressure adjusting valve that is provided between the separator and the orifice in the steam flow unit and that changes the opening degree of the flow path in the steam flow unit,
It is provided in a primary side drain flow path which is a downstream side of the first heat exchanger in the path through which the drain flows, and an upstream side of a trap which collects the drain separated by the separator. A thermometer for detecting the temperature of the drain flowing through the side drain distribution path,
A control unit for controlling the opening of the pressure regulating valve based on the temperature of the thermometer;
The steam heat exchange system according to claim 2 or 3, further comprising: A pressure adjusting valve that is provided between the separator and the orifice in the steam flow unit and that changes the opening degree of the flow path in the steam flow unit,
A pressure gauge provided between the pressure regulating valve and the orifice or between the orifice and the second heat exchanger, the pressure gauge detecting the pressure of the steam flowing through the steam flowing unit;
Based on the pressure of the pressure gauge, a control unit for controlling the opening of the pressure regulating valve,
The steam heat exchange system according to claim 2, further comprising: An electric valve that is provided between the separator and the orifice in the steam flow unit and switches between opening and closing of a flow path in the steam flow unit,
A pressure gauge that is provided between the motor-operated valve and the orifice in the steam flow section or between the orifice and the second heat exchanger, and detects the pressure of the steam flowing through the steam flow section,
When the pressure of the pressure gauge exceeds a predetermined first threshold value, the electrically operated valve is closed, and when the pressure of the pressure gauge falls below a predetermined second threshold value that is smaller than the first threshold value, the electrically operated valve is opened. A control unit,
The steam heat exchange system according to claim 2, further comprising: The pressure of the internal space is set to be equal to or lower than atmospheric pressure, the drain separated by the separator is supplied to the internal space, and a flash tank for generating flash vapor from the supplied drain is provided,
The steam heat exchange system according to claim 1, wherein the flash steam generated in the flash tank is supplied to the second heat exchanger.

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