JP2011025206A - Degassed water supply system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance the degassing capacity of a degassing device. <P>SOLUTION: In this degassed water supply system equipped with the first water supply pump 3 provided to a water supply line 2 for supplying the water in a raw water tank 1 to use machinery, the degassing device 5 provided to the circulating line 4 connected between the raw water tank 1, the raw water tank 1 of the water supply line 2 and the first water supply pump 3 and a second water supply pump 7 for sending the degassed water from the degassing device 5 to the connection point 6 of the water supply line 2 and the circulating line 4, the minimum flow line 11 of the first water supply pump 3 is connected across the downstream side of the first water supply pump 3 of the water supply line 2 and the raw water tank 1 and degassing device 5 of the circulating line 4 and a heat exchanger 12 for heating the water flowing through the minimum flow line 11 is provided. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a deaerated water supply system that supplies deaerated water to equipment used such as a steam boiler.

  Conventionally, a raw water tank, a water supply line for supplying water from the raw water tank to equipment used, a first water supply pump provided in the water supply line, the raw water tank, the raw water tank of the water supply line, and the first water supply pump A circulation line connected between the two, a deaeration device provided in the circulation line, and a second feed water pump for feeding degassed water by the deaeration device toward the feed line and the connection point of the circulation line A deaerated water supply system including the above is known from Patent Document 1 and the like.

  In the deaerated water supply system described in Patent Document 1, the first water supply pump may be required in terms of specifications to allow a minimum flow to flow even when there is no water supply requirement for the equipment used. It is not utilized in.

JP 2004-138304 A

  The problem to be solved by the present invention is to improve the deaeration capability of the deaeration device.

  This invention was made in order to solve the said subject, and invention of Claim 1 is provided in this water supply line, the water supply line which supplies the raw | natural water tank, the water of this raw | natural water tank to use equipment, and this water supply line A first feed water pump, a circulation line connected between the raw water tank and the raw water tank of the feed water line and the first feed water pump, a deaeration device provided in the circulation line, and a deaeration device In a deaerated water supply system comprising a second feed water pump that feeds deaerated water toward a connection point between the feed line and the circulation line, the downstream side of the first feed pump and the circulation line of the feed line A minimum flow line of the first feed pump is connected between the raw water tank and the deaeration device, and the minimum flow line is allowed to flow through the minimum flow line. It is characterized by comprising a heat exchanger for heating that water.

  According to this invention, during operation of the deaeration device, the water flowing through the minimum flow line is heated by the heat exchanger and supplied to the deaeration device. Thus, the deaeration performance of the deaerator can be improved, and the dissolved oxygen concentration (hereinafter referred to as DO) of the treated water can be reduced. In addition, when the deaerator is stopped, water flowing through the minimum flow line can be supplied to the raw water tank and used as supply water to the equipment used.

It is a schematic explanatory drawing which shows the structure of Example 1 of the deaeration water supply system which concerns on this invention. It is a flowchart figure explaining the principal part of the control procedure of the Example 1. FIG.

  Next, an embodiment of the present invention will be described. The deaerated water supply system of this embodiment is suitably implemented for boilers such as steam boilers, hot water boilers, and domestic water heaters.

  This embodiment will be specifically described. This embodiment includes a raw water tank, a water supply line for supplying water from the raw water tank to equipment used, a first water supply pump provided in the water supply line, both ends of the raw water tank and the raw water tank of the water supply line. And a circulation line connected between the first feed water pump, a deaeration device provided in the circulation line, and deaerated water by the deaeration device toward a connection point of the water supply line and the circulation line It is a deaeration water supply system provided with the 2nd water supply pump which supplies water.

  In this embodiment, further, both ends of the minimum flow line of the first water supply pump between the downstream side of the first water supply pump of the water supply line and between the raw water tank and the deaeration device of the circulation line. And a heat exchanger for heating the water flowing through the minimum flow line to the minimum flow line, and a control means for controlling the first water supply pump, the second water supply pump, and the deaeration device. .

  In the deaerated water supply system of this embodiment, during the operation of the deaerator, treated water deaerated by the deaerator is supplied to the raw water tank and the first water by the second water supply pump. It supplies toward between feed water pumps, and the one part is supplied to the said use apparatus by said 1st feed water pump. The remainder of the treated water is supplied to the raw water tank, and circulation deaeration is performed in which the water in the raw water tank is supplied to the deaeration device. And the water which flows through the said minimum flow line is heated with the said heat exchanger, and is supplied to the said deaeration apparatus. As a result, the temperature of the degassed water rises, the degassing performance of the degassing device is improved, and the dissolved oxygen concentration (hereinafter referred to as DO) of the treated water is lowered.

  Further, when the operation of the deaerator is stopped (hereinafter simply referred to as stop), the second water supply pump is stopped, so that water flowing through the minimum flow line is supplied to the raw water tank, and It is used as part of the water supply to the equipment used by a single water supply pump.

  Here, the component which comprises the deaerated water supply system of embodiment of this invention is demonstrated.

  The raw water tank is not limited to a tank having a specific structure as long as treated water from the deaeration device is circulated with the deaeration device.

  The device used is a device such as a boiler that uses treated water, and is not limited to a specific device. The water supply line is a conduit for supplying water from the raw water tank to the equipment used, and also functions as a conduit through which treated water that is deaerated water flows when the deaerator is in operation.

  The first water supply pump has a water supply capacity (water supply amount per unit time) that matches the maximum required treatment water amount of the equipment used.

  The circulation line is a pipe line that connects the raw water tank and the raw water tank and the first water supply pump of the water supply line.

The deaeration device is provided in the circulation line, preferably a deaeration vessel (treatment tank), a raw water pump that supplies raw water to the deaeration vessel, and a vacuum pump that depressurizes the deaeration vessel. And a deaeration device that performs a deaeration process by spraying the water to be treated onto the deaeration container in a reduced pressure state (a deaeration device as disclosed in JP 2009-68997 A, a tower type deaeration It is also referred to as a gas device).

  However, the degassing device can be a membrane degassing device. In the case of a membrane degassing device, a depressurizing means such as a vacuum pump is provided, and the operation of the degassing device means that the depressurizing means is operated. means. The reason why the tower type deaerator is preferable is that the heat resistance against the hot water heated by the heat exchanger of the minimum flow line is high.

  The second water supply pump has a function of sending treated water generated by the deaeration device toward a connection point of the water supply line and the circulation line, and as a component of the deaeration device, It can also be provided in the deaeration device or can be provided as a separate element from the deaeration device. The water supply capacity of the second water supply pump is larger than the water supply capacity of the first water supply pump. Thereby, a part of the water sent by the second water supply pump is supplied to the equipment used by the first water supply pump, and the rest is supplied to the raw water tank.

  The minimum flow line has a minimum flow rate in order to prevent the first water pump from overheating due to a decrease in the amount of water supplied to the equipment used, such as when the water pump on the equipment used stops. It is for flowing. This minimum flow line is provided with a flow rate adjusting means such as a flow rate adjusting valve for setting a minimum flow rate.

  The heat exchanger is for heating the water flowing through the minimum flow line by a heating means to raise the temperature. In the case where the equipment used is a boiler, the heating means may be configured to indirectly heat with a recovered drain, but may be a heating means such as an electric heater. When using the recovered drain, the waste heat is effectively used.

  The control means controls the operation of the first water supply pump, the second water supply pump, the deaeration device, and the like based on a processing procedure stored in advance based on a signal from a water level sensor that detects the water level of the raw water tank.

  As the processing procedure, the first water supply pump is operated both when the deaeration device is operated and stopped, and the second water supply pump is operated and stopped when the deaeration device is operated and stopped, respectively. be able to.

  The deaerator can be operated and stopped by various controls. In the first aspect, based on the signal from the water level sensor, the deaeration device is stopped when the raw water tank is at a low water level (in this case, the stop is interlocked), and otherwise, the deaeration device is operated. Is. The control of the first aspect is applicable not only to the tower type deaerator but also to the membrane deaerator.

  In addition, the second mode is to operate and stop in conjunction with the device used, that is, to capture the operation signal of the device to be used in the control means and shift the timing using the same timing as the device used or a timer. The deaerator is operated and stopped. The control of the second aspect is not limited to the tower type deaerator, but can be applied to a membrane deaerator.

Furthermore, a 3rd aspect sets operation time by the built-in timer in the said control means, and controls the operation | movement and a stop of the said deaeration apparatus. This third aspect can also be applied to a membrane deaerator that deaerates with a water-sealed vacuum pump. In the third aspect, when the water-sealed vacuum pump is used, a water level sensor can be provided in the sealed water tank, and the deaeration device can be stopped when it is determined that the water level is absent. The control of the deaeration device by the water level is configured to be performed independently of the control by the timer.

  Next, a deaerated water supply system according to Embodiment 1 of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic explanatory diagram illustrating a configuration of the first embodiment, and FIG. 2 is a flowchart illustrating a main part of a control procedure of the first embodiment.

  The deaerated water supply system includes a raw water tank 1, a water supply line 2 that supplies water from the raw water tank 1 to a boiler (not shown) as equipment to be used, and a first water supply pump 3 provided in the water supply line 2. A circulation line 4 connecting the raw water tank 1 and the raw water tank 1 of the feed water line 2 and the first feed water pump 3, a deaeration device 5 provided in the circulation line 4, and the deaeration device 5, a second water supply pump 7 that supplies degassed water 5 toward the first connection point 6 of the water supply line 2 and the circulation line 4, and a controller 8.

  Further, a minimum flow line 11 is provided for flowing the minimum flow rate of the first water supply pump 3. This minimum flow line 11 is a third connection point 9 between the second water supply line 2 downstream of the first water supply pump 3 and the circulation line 4 between the raw water tank 1 and the deaeration device 5. The connection point 10 is connected to communicate. The minimum flow line 11 includes an indirect heat exchange type heat exchanger 12 that heats (heats) water flowing through the minimum flow line to about 60 ° C., and a flow rate that sets the minimum flow rate. A flow rate adjusting valve 13 as an adjusting means and a flow meter 14 for detecting and displaying the flow rate of the minimum flow line 11 are provided.

  The raw water tank 1 is an open container and has a makeup water line (reference numeral omitted). Further, the first water supply pump 3 has a water supply capacity that matches the maximum required treatment water amount of the boiler, and the water supply capacity of the second water supply pump is larger than the water supply capacity of the first water supply pump. .

  The deaeration device 5 includes a deaeration tank 15, a water-sealed vacuum pump 16 that depressurizes the deaeration tank 15, and a tower including a raw water pump 17 that supplies raw water into the deaeration tank 15. The deaerator is also called a type deaerator.

  The flow rate adjusting valve 13 is for adjusting the flow rate so that the minimum flow limit amount for preventing overheating of the first water supply pump 3 due to a decrease in the water supply amount to the boiler flows to the minimum flow line 11. Is. In the first embodiment, the decrease in the amount of water supplied to the boiler occurs when the amount of water supplied becomes zero when a water supply pump (not shown) provided on the boiler side stops, but is caused by other factors. May be.

  The heat exchanger 12 is configured to indirectly heat the water flowing through the minimum flow line 11 by the heating means 18. The heating means 18 is a pipe through which the recovered drain after use of the steam of the boiler is used by a steam-using device.

  The controller 8 operates the first water supply pump 3, the second water supply pump 7, the vacuum pump 16, the raw water pump 17, and the like based on a signal from a water level sensor 19 that detects the water level of the raw water tank 1. Is controlled based on a pre-stored processing procedure. The main part of this processing procedure is shown in FIG.

  The processing procedure of FIG. 2 includes the first control procedure for controlling the operation of the deaeration device 5, that is, the operation of the vacuum pump 16 and the raw water pump 17, the first water supply pump 3 and the second water supply pump 7. And a second control procedure for controlling.

  The first control procedure is based on the signal of the water level sensor 18 and stops the vacuum pump 16 and the raw water pump 17 of the deaeration device 5 at a low water level below the predetermined water level of the raw water tank 1, and at other water levels. Operates the vacuum pump 16 and the raw water pump 17 of the deaeration device 5.

  The operation of the deaeration device 5 is stopped unless it is stopped by an interlock, that is, the stop is released by the lock release means. In the first embodiment, the operation of the vacuum pump 16 means that the operation is controlled so that the degree of vacuum in the deaeration tank 15 falls within a predetermined range. In operation of the raw water pump, in Example 1, the raw water pump is used as a pump whose rotation speed can be controlled. When the vacuum pump 16 is operated, raw water is supplied into the deaeration container 15 at a constant flow rate per unit time. It means to control.

  In the second control procedure, the first water supply pump 3 is operated both when the deaeration device 5 is operated and when it is stopped (regardless of operation or stop), and the second water supply pump 7 is operated when the deaeration device 5 is operated. The system is configured to stop and operate during operation and when stopped.

  Here, the operation of the first embodiment will be described with reference to FIG. Referring to FIG. 2, in process step S1 (hereinafter, process step SN is simply referred to as SN), it is determined whether a system operation start switch (not shown) has been operated.

  If YES is determined in S <b> 1, the process proceeds to S <b> 2 and the first water supply pump 3 is operated. Next, in S3, the deaeration device 5 is operated, that is, the second water supply pump 7, the vacuum pump 16 and the raw water pump 17 are operated.

  The flow of water during this deaeration operation is indicated by solid arrows in FIG. The deaerated treated water in the deaeration tank 10 is supplied toward the first connection point 6 by the second water supply pump 7. A part of the treated water is supplied to the boiler by the first water supply pump 3. The remainder of the treated water is supplied to the raw water tank 1, and circulation deaeration is performed in which the water in the raw water tank 1 is supplied to the deaeration device 5.

  A part of the treated water discharged from the first water supply pump 3 flows through the minimum flow line 11, is heated by the heat exchanger 12 at that time, and is returned to the deaeration device 5. The water from the raw water tank 1 and the water in the minimum flow line 11 flow into the deaeration device 5, but the degassed as a whole by the heated water from the minimum flow line 11. The water temperature will rise. As a result, the deaeration performance of the deaeration device 5 is improved, and the DO of treated water is reduced as compared with the case where the deaerator 5 is not heated by the heat exchanger 12.

  In S4, the water level of the raw water tank 1 is monitored, and if the water level falls below a set value for some reason, it is determined that the water level is low, and the deaeration device 5 is stopped, that is, the vacuum pump 16 and the raw water pump 17 And the second water supply pump 7 is stopped.

  The flow of water when the deaeration device 5 is stopped is indicated by broken arrows in FIG. Part of the water in the raw water tank 1 is supplied to the boiler by the first water supply pump 3. The rest flows through the minimum flow line 11, flows into the raw water tank 1, and circulates again to the minimum flow line 11. The circulating water does not flow into the deaeration tank 15 because the raw water pump 17 and the second water supply pump 7 are stopped, but the raw water pump 17 and the second water supply pump 7 are surely prevented from flowing in. An electromagnetic valve (not shown) can be provided on each upstream side or downstream side. Thus, when the deaeration device 5 is stopped, the water flowing through the minimum flow line 11 is used for water supply to the boiler.

  In S6, it is determined whether a system operation stop switch (not shown) has been operated. This switch is operated when the overall system operation of the first embodiment is stopped, such as when releasing the interlock for stopping the deaeration device 5.

  If YES is determined in S6, the process proceeds to S7, and the first water supply pump 3 is stopped.

  According to the first embodiment, since the water flowing through the minimum flow line 11 is heated by the heat exchanger 12 and supplied to the deaeration device 5 during operation of the deaeration device 5, The temperature of deaeration water rises and the deaeration performance of the deaeration device is improved. As a result, low DO treated water can be supplied.

  Further, since the water flowing through the minimum flow line 11 during the operation of the deaeration device 5 is water that has been deaerated, compared to the case where the heat exchanger 12 is provided on the primary side of the deaeration device 5. Since DO is low, the heat exchanger 12 is effective for anticorrosion.

  Furthermore, water flowing through the minimum flow line 11 when the deaeration device 5 is stopped is supplied to the raw water tank 1 and can be effectively used as supply water to the boiler, and the feed water temperature to the boiler rises. Therefore, the amount of heat for changing from water to steam in the boiler is small.

DESCRIPTION OF SYMBOLS 1 Raw water tank 2 Water supply line 3 1st water supply pump 4 Circulation line 5 Deaeration device 7 2nd water supply pump 8 Controller (control means)
11 Minimum flow line 12 Heat exchanger

Claims (1)

Between the raw water tank, a water supply line for supplying water from the raw water tank to equipment used, a first water supply pump provided in the water supply line, and between the raw water tank and the raw water tank and the first water supply pump of the water supply line A circulation line connected to the circulation line, a deaeration device provided in the circulation line, and a second feed water pump for feeding deaerated water by the deaeration device toward the connection line and the connection point of the circulation line In the deaerated water supply system provided,
Connecting a minimum flow line of the first water supply pump between the downstream side of the first water supply pump of the water supply line and between the raw water tank and the deaeration device of the circulation line;
A deaerated water supply system comprising a heat exchanger for heating water flowing through the minimum flow line in the minimum flow line.

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