JP2020041771A - Steam generating device - Google Patents

Abstract

To provide a steam generating device that can generate clean steam with higher cleanliness while enhancing utilization efficiency of heat.SOLUTION: A steam generating device 1 which has a pressure vessel 10, and a tube 20 arranged inside the pressure vessel 10 and inside which steam flows, and generates steam by heating stored water inside the pressure vessel 10 by steam flowing through the tube 20, comprises: a steam supply line L1 for supplying steam to the tube 20; a drain discharge line L2 for discharging drain having flowed through the tube 20; a water supply line L3 for supplying water to the pressure vessel 10; water supply means 33 for continuously supplying the water to the pressure vessel 10 so that a water level in the pressure vessel 10 becomes a target water level; and a heat exchanger 30 for exchanging heat between the water flowing through the water supply line L3 and the drain flowing through the drain discharge line L2.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a steam generator. More specifically, the present invention relates to a steam generator that generates clean steam by indirect heat exchange between steam and water.

  Conventionally, a clean steam generator has been proposed in which pure water stored in a pressure tank is indirectly heat-exchanged using steam generated by a boiler to generate clean steam (clean steam) (for example, Patent Document 1). 1).

JP 2010-002057 A

  In the clean steam generator proposed in Patent Document 1, drain water generated by condensing steam used as a heat source for generating clean steam is stored in a tank and used as water for generating clean steam. I have.

  As described above, when the drain water obtained from the steam used as the heat source is used as the water for generating the clean steam, the heat possessed by the drain water can be effectively used, while the cleanness of the clean steam is sufficiently improved. May not be secured.

  Therefore, an object of the present invention is to provide a steam generator capable of generating clean steam with higher cleanliness while increasing the heat use efficiency.

  The present invention has a pressure vessel, and a tube disposed inside the pressure vessel and through which steam flows, and generating steam by heating the stored water inside the pressure vessel with the steam flowing through the tube. A steam generator, a steam supply line for supplying steam to the tube, a drain discharge line for discharging drain flowing through the tube, a water supply line for supplying water to the pressure vessel, and a water supply line, Water supply means for continuously supplying water to the pressure vessel so that the water level of the pressure vessel becomes a predetermined target water level; and heat for performing heat exchange between water supplied through the water supply line and the drain flowing through the drain discharge line. And a heat exchanger.

  In addition, it is preferable that the steam generator further includes a pressure loss portion disposed downstream of the heat exchanger in the water supply line.

  In addition, it is preferable that the water supply means is disposed upstream of the heat exchanger in the water supply line.

  Further, the steam generator, one end side is connected to the drain exchanger in the upstream side of the heat exchanger in the drain discharge line, the other end side is connected to the drain outlet line in the downstream side of the heat exchanger in the downstream side, It is preferable to further include a bypass valve for switching a drain flow path to the heat source fluid discharge line side or the bypass line side.

  In the steam generator, a feedwater temperature measuring unit that measures the temperature of the feedwater downstream of the heat exchanger, and the temperature of the feedwater measured by the feedwater temperature measuring unit exceeds a preset first temperature. In this case, it is preferable to further include a bypass control unit that controls the bypass valve so that the drain flowing through the drain discharge line flows through the bypass line.

  ADVANTAGE OF THE INVENTION According to the steam generator of this invention, the clean steam of higher cleanliness can be generated, raising the heat utilization efficiency.

It is a figure showing the whole steam generator concerning one embodiment of the present invention.

Hereinafter, a preferred embodiment of the steam generator of the present invention will be described with reference to the drawings.
The steam generator 1 of the present embodiment generates clean steam (clean steam) by indirect heat exchange of pure water stored in a pressure vessel using steam generated by a boiler. As shown in FIG. 1, the steam generator 1 includes a pressure vessel 10, a tube 20 disposed inside the pressure vessel 10, a steam supply line L1, a drain discharge line L2, a water supply line L3, It includes an exchanger 30, a bypass line L4, a clean steam line L5, and a control unit 90.

The pressure vessel 10 is constituted by a vessel having pressure resistance, and stores water (retained water) inside. In the present embodiment, the pressure vessel 10 is formed of a pressure-resistant vessel made of stainless steel.
A pressure sensor 11 and a water level sensor 12 are attached to the pressure vessel 10.
The pressure sensor 11 detects the pressure inside the pressure vessel 10. The water level sensor 12 detects the level of the stored water stored in the pressure vessel 10.

  The tube 20 is arranged inside the pressure vessel 10. More specifically, the tube 20 has one end and the other end penetrating through the side surface of the pressure vessel 10 and disposed outside the pressure vessel 10, and an intermediate portion in which the stored water in the pressure vessel 10 is stored. (Liquid phase portion). In the present embodiment, a plurality of tubes 20 bent in a U-shape are arranged inside the pressure vessel 10. The tube 20 is made of a metal material having good thermal conductivity (for example, stainless steel).

  The upstream side of the steam supply line L <b> 1 is connected to a steam generator (not shown) such as a steam boiler, and the downstream side is connected to one end (upstream end) of the tube 20. The steam supply line L1 supplies steam to the tube 20. A steam flow regulating valve 13 is arranged in the steam supply line L1. The steam flow control valve 13 is configured by a motor valve or the like whose opening degree can be adjusted, and adjusts the flow rate of steam flowing through the steam supply line L1 (that is, the flow rate of steam supplied to the tube 20).

  The upstream side of the drain discharge line L2 is connected to the other end of the tube 20 (the downstream end). The drain discharge line L2 discharges drain generated by condensation of steam supplied from the steam supply line L1 to the tube 20 by indirect heat exchange with stored water inside the pressure vessel 10. A steam trap 21 and a bypass valve 22 are arranged in the drain discharge line L2.

  The steam trap 21 is disposed upstream (in the vicinity of the pressure vessel 10) of the drain discharge line L2. The steam trap 21 operates in a state where a pressure difference is generated in the drain discharge line L2 before and after, and discharges the drain generated in the tube 20 and prevents the discharge of steam.

  The bypass valve 22 is disposed downstream of the steam trap 21 in the drain discharge line L2. The bypass valve 22 switches the flow path of the drain discharged from the tube 20 and flowing through the drain discharge line L2 to a downstream side of the drain discharge line L2 or a bypass line L4 described later. In the present embodiment, the bypass valve 22 is configured by a three-way valve attached to a connection portion between the drain discharge line L2 and the bypass line L4.

  The upstream side of the water supply line L3 is connected to a water supply source (not shown), and the downstream side is connected to a lower portion of the pressure vessel 10. The water supply line L3 supplies water to the pressure vessel 10. In the present embodiment, the water supply line L3 includes a pure water device 31, a deaerator 32, a water supply pump 33 as a water supply means, a heat exchanger 30, a water supply temperature sensor 34 as a water supply temperature measuring unit, and a pressure loss unit as An orifice 35 is arranged.

The pure water apparatus 31 includes, for example, a cation exchange resin and an anion exchange resin, and adsorbs various ions contained in raw water supplied from a water supply source to the ion exchange resin to treat water (pure water). To manufacture.
The deaerator 32 is disposed downstream of the pure water device 31. The deaerator 32 performs deoxygenation treatment on the feedwater (pure water) flowing through the feedwater line L3 to produce deaerated water.
The water supply pump 33 is disposed downstream of the deaerator 32 and supplies clean water that has passed through the pure water device 31 and the deaerator 32 to the pressure vessel 10. In the present embodiment, the water supply pump 33 continuously supplies water to the pressure vessel 10 so that the water level of the pressure vessel 10 becomes a predetermined target water level under the control of the control unit 90 described below.

  The heat exchanger 30 performs indirect heat exchange between the water flowing through the water supply line L3 and the drain flowing through the drain discharge line L2. Thereby, the water supply flowing through the water supply line L3 is heated by the drain flowing through the drain discharge line L2. The heat exchanger 30 is arranged downstream of the water supply pump 33 in the water supply line L3 and downstream of the bypass valve 22 in the drain discharge line L2.

The feedwater temperature sensor 34 is arranged downstream of the heat exchanger 30. The feedwater temperature sensor 34 detects the temperature of feedwater on the downstream side of the heat exchanger 30.
The orifice 35 is disposed on the most downstream side of the water supply line L3 (near the connection with the pressure vessel 10). The orifice 35 causes a pressure loss in water supplied through the water supply line L3.

  The bypass line L4 has one end connected upstream of the heat exchanger 30 in the drain discharge line L2 and the other end connected downstream of the heat exchanger 30 in the drain discharge line L2. The bypass line L4 allows the drain flowing through the drain discharge line L2 to flow while bypassing the heat exchanger 30. In the present embodiment, as described above, the bypass valve 22 is disposed at a connection portion between the drain discharge line L2 and one end (upstream side) of the bypass line L4.

  The upstream side of the clean steam line L5 is connected to the upper part of the pressure vessel 10, and the downstream side is connected to steam utilization equipment (not shown). The clean steam line L5 supplies steam generated inside the pressure vessel 10 to a steam utilization facility.

  The control unit 90 controls the operation of the steam generator 1 by controlling various valves, the water supply pump 33, and the like. Specific control of the control unit 90 will be described later.

  According to the steam generator 1 described above, the water supplied from the water supply source is processed by the pure water device 31 and the deaerator 32, introduced into the pressure vessel 10 by the water supply pump 33, and stored as stored water. Here, the heat exchanger 30 is disposed downstream of the water supply pump 33 in the water supply line L3. As a result, the water flowing through the water supply line L3 is introduced into the pressure vessel 10 while being heated by the drain flowing through the drain discharge line L2 on the downstream side of the water supply pump 33. Further, an orifice 35 as a pressure loss portion is disposed at the most downstream side (near the inlet of the pressure vessel 10) in the water supply line L3. As a result, a predetermined pressure is applied to the water supply upstream of the orifice 35 in the water supply line L3, and the boiling point (saturation temperature) of the water supply rises.

The stored water stored inside the pressure vessel 10 is heated by indirect heat exchange with the steam supplied from the steam supply line L1 to the tube 20. Then, the stored water is boiled by being heated, and steam is generated inside the pressure vessel 10. This steam is generated by heating clean storage water by indirect heat exchange, so that it becomes clean clean steam.
The clean steam generated inside the pressure vessel 10 is supplied to a steam utilization facility through a clean steam line L5.

On the other hand, the steam supplied from the steam supply line L1 to the tube 20 is condensed by indirect heat exchange with the stored water inside the pressure vessel 10 to become a drain. Drain generated by condensation of the steam is discharged through a drain discharge line L2. The drain flowing through the drain discharge line L2 performs indirect heat exchange with the feedwater flowing through the water supply line L3 in the heat exchanger 30 to heat the feedwater. The drain used for heating the feedwater in the heat exchanger 30 is discharged to the outside (for example, a drain tank (not shown) for storing the drain).
When the bypass valve 22 arranged in the drain discharge line L2 is switched to the bypass line L4 side, the drain flowing through the drain discharge line L2 bypasses the heat exchanger 30 and flows through the bypass line L4, Is discharged.

Next, control by the control unit 90 will be described.
In the present embodiment, the control unit 90 continuously supplies water to the pressure vessel 10 so that the water level of the pressure vessel 10 becomes a predetermined target water level, thereby supplying the water flowing through the water supply line L3 and the drain flowing through the drain discharge line L2. The balance of the flow rates is kept good, and the heat utilization efficiency is improved without increasing the size of the steam generator 1. In order to realize such a function, the control unit 90 is configured to include a water supply control unit 91, a steam supply control unit 92, and a bypass control unit 93.

  The water supply control unit 91 controls the output (the number of revolutions) of the water supply pump 33 so that the water level of the pressure vessel 10 becomes a predetermined target water level set in advance, and continuously supplies water to the pressure vessel 10 from the water supply line L3. . More specifically, the control unit 90 sets and stores a target water level that is a suitable water level of the stored water in the pressure vessel 10. Then, the water supply control unit 91 controls the output of the water supply pump 33 so that the water level detected by the water level sensor 12 matches the target water level.

  For example, when the detected water level is low and the deviation from the target water level is large, the water supply control unit 91 increases the output of the water supply pump 33 to increase the amount of water flowing through the water supply line L3. On the other hand, when the detected water level approaches the target water level and the deviation decreases, the water supply control unit 91 reduces the output of the water supply pump 33 to reduce the amount of water flowing through the water supply line L3.

  The steam supply control unit 92 controls the amount of steam supplied to the tube 20 based on the steam pressure of the clean steam inside the pressure vessel 10. More specifically, the target vapor pressure of the clean vapor inside the pressure vessel 10 is set and stored in the control unit 90. Then, the steam supply control unit 92 adjusts the opening of the steam flow control valve 13 so that the steam pressure of the clean steam detected by the pressure sensor 11 matches the target steam pressure, and supplies the steam to the tube 20. Control the amount.

  For example, when the detected steam pressure of the clean steam is low and the deviation from the target steam pressure is large, the steam supply control unit 92 increases the opening of the steam flow control valve 13 and supplies the clean steam to the tube 20. Increase the amount of steam. On the other hand, when the detected steam pressure of the clean steam approaches the target steam pressure and the deviation decreases, the steam supply control unit 92 reduces the opening of the steam flow control valve 13 and supplies the steam flow to the tube 20. Reduce the amount of steam generated.

According to the above control, for example, when the amount of clean steam used in the steam utilization facility increases, the steam pressure of the clean steam inside the pressure vessel 10 decreases. Then, the steam supply control unit 92 increases the degree of opening of the steam flow control valve 13 to increase the amount of steam supplied to the tube 20 and increases the generation of clean steam inside the pressure vessel 10 to increase the pressure. The steam pressure of the clean steam inside the container 10 is increased. When the supply amount of the steam to the tube 20 increases, the amount of the drain generated from the steam also increases, so that the flow rate of the drain flowing through the drain discharge line L2 also increases. Further, when the amount of generated clean steam inside the pressure vessel 10 increases, the amount of evaporation of the stored water in the pressure vessel 10 increases, so that the water level inside the pressure vessel 10 decreases. Then, the water supply control unit 91 increases the output of the water supply pump 33 to increase the flow rate of the supply water flowing through the water supply line L3, and raises the water level inside the pressure vessel 10.
As described above, according to the present embodiment, when the supply amount of steam to the tube 20 increases and the flow rate of the drain flowing through the drain discharge line L2 increases, the flow rate of the supply water flowing through the water supply line L3 also increases. Will increase.

On the other hand, when the amount of clean steam used in the steam utilization facility decreases, the steam pressure of the clean steam inside the pressure vessel 10 increases. Then, the steam supply control unit 92 reduces the pressure of the steam flow control valve 13 by reducing the opening degree of the steam flow control valve 13 to reduce the amount of steam supplied to the tube 20 and reducing the generation of clean steam inside the pressure vessel 10. The steam pressure of the clean steam inside the container 10 is reduced. When the supply amount of the steam to the tube 20 decreases, the amount of the drain generated from the steam also decreases, so that the flow rate of the drain flowing through the drain discharge line L2 also decreases. Further, when the amount of clean steam generated inside the pressure vessel 10 decreases, the evaporation amount of the stored water in the pressure vessel 10 decreases, so that the water level inside the pressure vessel 10 rises. Then, the water supply control unit 91 reduces the output of the water supply pump 33 to reduce the flow rate of the supply water flowing through the water supply line L3, and lowers the water level inside the pressure vessel 10.
As described above, according to the present embodiment, when the supply amount of steam to the tube 20 decreases and the flow rate of the drain flowing through the drain discharge line L2 decreases, the flow rate of the supply water flowing through the water supply line L3 also increases. Will decrease.

  The bypass control unit 93 controls the bypass valve so that the drain flowing through the drain discharge line L2 flows through the bypass line L4 when the temperature of the feedwater measured by the feedwater temperature sensor 34 exceeds the preset first temperature. 22 is controlled. Thereby, when the temperature of the feedwater flowing through the water supply line L3 becomes too high, the supply of the drain to the heat exchanger 30 can be stopped, so that the feedwater flowing through the water supply line L3 is prevented from boiling. it can. The first temperature is preferably set to a temperature slightly lower than the saturation temperature at the set pressure of the feedwater flowing through the feedwater line L3.

  According to the steam generator 1 of the present embodiment described above, the following effects can be obtained.

(1) The steam generator 1 is operated such that heat is exchanged between the water flowing through the water supply line L3 and the drain flowing through the drain discharge line L2, and the water level of the pressure vessel 10 becomes the target water level. And a water supply pump 33 for continuously supplying water to the pressure vessel 10. Thus, when the amount of clean steam generated in the pressure vessel 10 is large in the steam utilization facility, the amount of water supply and the amount of steam supplied to the tube 20 are increased in order to generate a large amount of clean steam. When the amount of steam used in the equipment is small, the amount of water supply and the amount of steam supplied to the tube 20 are reduced in order to reduce the amount of generated clean steam. Therefore, when the flow rate of the supply water flowing through the water supply line L3 is large, the flow rate of the drain flowing through the drain discharge line L2 can be increased, and when the flow rate of the supply water flowing through the water supply line L3 is small, the flow flows through the drain discharge line L2. The amount of drain circulation can be reduced. As a result, the balance between the heat exchange between the water supply and the drain in the heat exchanger 30 is not largely disturbed, so that the heat can be stably recovered by the water supply. Therefore, even when clean steam is generated using highly clean water such as pure water or soft water, it is possible to realize the steam generator 1 capable of increasing the heat use efficiency.
Further, by performing continuous water supply in the water supply line L3, it is possible to prevent the water supply in the water supply line L3 from staying, so that it is possible to suppress the supply water flowing through the water supply line L3 in the heat exchanger 30 from being overheated and boiling. .
Further, for example, highly clean water such as pure water produced by the pure water device 31 can be supplied to the pressure vessel 10 in one pass without being stored in another tank or the like in the middle of the water supply line L3. Can keep the cleanliness higher.

  (2) The steam generator 1 is configured to include the orifice 35 disposed downstream of the heat exchanger 30 in the water supply line L3. This makes it possible to increase the boiling point of the feedwater by applying a predetermined pressure to the feedwater flowing through the feedwater line L3. Therefore, in the heat exchanger 30, the feedwater flowing through the feedwater line L3 and the drain flowing through the drain discharge line L2 are connected. Allows more heat to be exchanged between. Therefore, the heat recovery rate can be increased.

  (3) The water supply pump 33 is disposed upstream of the heat exchanger 30 in the water supply line L3. Thus, the water supply pump 33 can be disposed at a position where the temperature of the water supply is low, so that the steam generator 1 can be configured without using a water supply pump compatible with high temperature water.

  (4) The steam generator 1 is configured to include a bypass line L4 connected to the drain discharge line L2 and bypassing the heat exchanger 30, and a bypass valve 22. Thereby, when the water supply to the pressure vessel 10 by the water supply line L3 is stopped or the like, the drain flowing through the drain discharge line L2 is allowed to flow by bypassing the heat exchanger 30. Therefore, the safety of the steam generator 1 can be improved.

  (5) The steam generator 1 is used to measure the temperature of the water supply on the downstream side of the heat exchanger 30 when the temperature of the water supply measured by the temperature sensor 34 exceeds the first temperature. And a bypass control unit 93 that controls the bypass valve 22 so that the drain flowing through the drain discharge line L2 flows through the bypass line L4. Thereby, when the temperature of the feedwater is too high, the supply of the drain to the heat exchanger 30 can be stopped. Therefore, since the supply water can be prevented from boiling, the safety of the steam generator 1 can be further improved.

As described above, one preferred embodiment of the steam generator 1 of the present invention has been described, but the present invention is not limited to the above-described embodiment, and can be appropriately changed.
For example, in the present embodiment, a three-way valve is used as the bypass valve 22, but the present invention is not limited to this. That is, the bypass valve may be constituted by two on-off valves disposed on the downstream side of the connection between the bypass line L4 and the drain line L4 in the bypass line L4 and the drain discharge line L2.

  In the present embodiment, the steam supply control unit 92 adjusts the opening of the steam flow control valve 13 so that the steam pressure of the clean steam detected by the pressure sensor 11 matches the target steam pressure. Although the supply amount of steam to the fuel cell was controlled, it is not limited to this. That is, the control unit stores the steam pressure of the clean steam inside the pressure vessel and the opening of the steam flow control valve in association with each other, and the steam supply control unit causes the steam pressure of the clean steam detected by the pressure sensor to be stored. The opening degree of the steam flow control valve may be controlled at an opening degree corresponding to.

  In the present embodiment, the steam generator 1 is configured to include the pure water device 31 and the deaerator 32, and the pure water is supplied to the pressure vessel 10. However, the present invention is not limited to this. The water supplied to the pressure vessel may be, for example, soft water from which a hardness component has been removed. In this case, the steam generator can be configured to include a water softener.

DESCRIPTION OF SYMBOLS 1 Steam generator 10 Pressure vessel 20 Tube 22 Bypass valve 30 Heat exchanger 33 Water supply pump (water supply means)
34 Water supply temperature sensor (water supply temperature measurement unit)
35 Orifice (pressure loss part)
93 Bypass control unit L1 Steam supply line L2 Drain discharge line L3 Water supply line L4 Bypass line

Claims (5)

A pressure vessel, and a steam generator that has a tube disposed inside the pressure vessel and through which steam flows, and that generates steam by heating the stored water inside the pressure vessel with the steam flowing through the tube. So,
A steam supply line for supplying steam to the tube,
A drain discharge line for discharging the drain flowing through the tube,
A water supply line for supplying water to the pressure vessel,
Water supply means arranged in the water supply line, a water supply means for continuously supplying water to the pressure vessel so that the water level of the pressure vessel becomes a predetermined target water level,
A steam generator, comprising: a heat exchanger that performs heat exchange between feedwater flowing through the feedwater line and drain flowing through the drain discharge line.   2. The steam generator according to claim 1, further comprising a pressure loss portion disposed downstream of the heat exchanger in the water supply line. 3.   3. The steam generator according to claim 1, wherein the water supply unit is disposed upstream of the heat exchanger in the water supply line. 4. A bypass line having one end connected upstream of the heat exchanger in the drain discharge line and the other end connected downstream of the heat exchanger in the drain discharge line;
The steam generator according to any one of claims 1 to 3, further comprising: a bypass valve configured to switch a drain flow path to the drain discharge line side or the bypass line side. A feedwater temperature measuring unit that measures the temperature of the feedwater on the downstream side of the heat exchanger,
A bypass that controls the bypass valve so that the drain flowing through the drain discharge line flows through the bypass line when the temperature of the feed water measured by the feed water temperature measurement unit exceeds a first temperature set in advance. The steam generator according to claim 4, further comprising: a control unit.

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