WO2018159299A1

WO2018159299A1 - Cooling tower system

Info

Publication number: WO2018159299A1
Application number: PCT/JP2018/005175
Authority: WO
Inventors: 孝次伊藤; 三輪　昌之
Original assignee: 栗田工業株式会社
Priority date: 2017-03-01
Filing date: 2018-02-15
Publication date: 2018-09-07

Abstract

When recirculation and supply of cooling water from a cooling tower 1 to a heat exchanger 4 is continued, the water level inside a pit 1d gradually decreases and electrical conductivity gradually increases. A pump 10 starts operation once the electrical conductivity reaches an intermediate value C1. The water supply from the pump 10 undergoes RO treatment by an RO device 13, concentrate is discharged outside the system, and permeate is introduced to the pit 1d. As a result of the inflow of permeate, there is a slow rise in electrical conductivity of the water inside the pit 1d. The electrical conductivity continues to increase and reaches an upper limit of C2. Once that happens, a forced replenishment water valve 22 opens and the replenishment water inside a replenishment water tank 15 is supplied to inside the pit 1d via pipes 19, 20.

Description

Cooling tower system

The present invention relates to a cooling tower system, and more particularly to a cooling tower system for collecting cooling tower blow water in an open circulation type cooling tower.

In the cooling tower system, when high concentration operation is performed with less discharge (blow) of cooling water outside the system, dissolved salts are concentrated and the heat transfer surface is easily corroded. Scales as a sparingly soluble salt. If the scale adheres to the wall surface of the apparatus, a serious obstacle occurs in the operation of the boiler and heat exchanger, such as a decrease in thermal efficiency and blockage of piping. In recent years, for the purpose of saving water and saving energy, the movement of effectively using water as much as possible has become remarkable. However, in the case of further highly concentrated operation, there is a limit in suppressing the precipitation of scale.

Therefore, the cooling tower blow water is passed through the MF membrane or UF membrane to remove turbidity in the blow water, and then RO membrane treatment is performed to remove ions, organic substances, etc., and return to the cooling tower (patent) References 1-4).

JP 2002-18437 A Japanese Patent Laid-Open No. 2003-1255 JP-A-2016-190224 JP2015-174030A

The object of the present invention is to provide a cooling tower system that can reduce blow water and make-up water and that can be easily controlled.

A cooling tower system according to a first aspect of the present invention is a cooling tower to which a circulation line of cooling water is connected, a means for measuring the electrical characteristic value (electric conductivity or specific resistance) of the cooling water, and the water in the cooling tower is pumped. Recovery means for sending water to the reverse osmosis membrane device and returning the permeated water of the reverse osmosis membrane device to the cooling tower or circulation line, and makeup water according to at least one of the water level in the cooling tower and the electrical characteristic value A cooling tower system having a makeup water supply means for supplying water, and a control means for operating the recovery means according to at least one of an electrical characteristic value of the cooling water and a water level of the blow water tank.

In one aspect of the present invention, as the recovery means, a blow water tank that receives the overflow water, the reverse osmosis membrane device that processes water pumped from the blow water tank, and the permeated water of the reverse osmosis membrane device Means for supplying to the cooling tower or the circulation line.

In one aspect of the present invention, the makeup water supply means is configured such that the electrical conductivity measured by the measurement means increases to a predetermined upper limit value C ₂ or the specific resistance decreases to a predetermined lower limit value R _2. Then, makeup water is supplied until the electrical conductivity decreases to a predetermined lower limit value C ₀ or the specific resistance increases to a predetermined upper limit value R ₀ .

In one aspect of the present invention, the control means increases the electrical conductivity of the cooling water to a predetermined intermediate value C ₁ (where C ₀ <C ₁ <C ₂ ) or the specific resistance has a predetermined intermediate value R. ₁ (provided that R ₂ <R ₁ <R ₀ ), the pump is started and the electrical conductivity decreases to the lower limit C ₀ or the specific resistance reaches the upper limit R ₀ . The pump is stopped when it rises to.

In one aspect of the present invention, the water in the blow water tank is made turbid by a turbidity means and then supplied to the reverse osmosis membrane device.

The cooling tower system of the second invention is a cooling tower system having a cooling tower and recovery means for treating the overflow water of the cooling tower and recovering it as make-up water, and accepting the overflow water as the recovery means A blow water tank, a reverse osmosis membrane device for treating water from the blow water tank, a replenishment water tank that receives the permeated water of the reverse osmosis membrane device, and means for supplying water in the replenishment water tank to the cooling tower as make-up water And control means for operating the recovery means according to the water level of the blow water tank or the water levels of the blow water tank and the makeup water tank.

In one aspect of the present invention, the control means includes a water level sensor that detects a water level in the blow water tank, and when the detected water level of the water level sensor rises to a predetermined upper limit value, When the water supply pump is started and the water level detected by the water level sensor is lowered to a specified lower limit value, the water supply pump is stopped.

In the cooling tower system of the present invention, the water recovery rate of the cooling tower can be increased by treating blow water and using it as cooling water.

In one aspect of the present invention (the aspect shown in FIG. 1), the blow water recovery means is managed by the electric conductivity or specific resistance of the cooling water or the electric conductivity or specific resistance and the water level of the blow water tank, thereby simplifying the control. It becomes.

In one aspect of the present invention (the aspect shown in FIG. 3), control is simplified by managing the means for collecting blow water according to the water levels of the blow water tank and the makeup water tank.

It is a flowchart which shows the cooling tower system which concerns on embodiment. It is a chart which shows the action | operation of the cooling tower system which concerns on embodiment. It is a flowchart which shows the cooling tower system which concerns on another embodiment. It is a chart which shows the action | operation of the cooling tower system which concerns on embodiment of FIG.

The first embodiment will be described with reference to FIGS.

As shown in FIG. 1, the cooling tower 1 of this cooling tower system is cooled in contact with the air introduced from the louver 1c while the cooling water sprinkled from the sprinkling pipe 1a flows down the filler layer 1b. The air that is stored in 1d (cooling tower lower water tank) and contains steam is configured to be exhausted into the atmosphere by a fan 1e. The cold water in the pit 1d of the cooling tower 1 is supplied to the heat exchanger 4 via the pump 2 and the pipe 3, and the return water from the heat exchanger 4 is returned to the water spray pipe 1a of the cooling tower 1 via the pipe 5. The

The pit 1 d is provided with an overflow pipe 7. When the water level in the pit 1 d becomes higher than the inlet 7 a at the upper end of the overflow pipe 7, the cooling water in the pit 1 d passes through the overflow pipe 7 and the blow water tank 8. Flow into. The cooling tower 1 is provided with an electric conductivity meter 24 for measuring the electric conductivity of the cooling water in the pit 1d.

The blow water tank 8 is provided with a water level sensor 9 and a pump 10 for circulating water. Signals from the electrical conductivity meter 24 and the water level sensor 9 are input to the pump controller 10a, and the pump 10 is controlled by signals from the pump controller 10a. The water supplied from the pump 10 is supplied to the RO device 13 via the turbidifier 11 and the pipe 12. As the turbidizer 11, a filter, an MF membrane device, a UF membrane device, or the like can be used.

The concentrated water of the RO device 13 is discharged out of the system, and the permeated water is supplied to the pit 1d via the pipe 14. Note that the downstream end of the pipe 14 may be connected to the pipe 3. In this embodiment, the equipment from the overflow pipe 7 and the blow water tank 8 to the pipe 14, the water level sensor 9, the electric conductivity meter 24, and the pump controller 10a constitute the recovery means.

In order to store the makeup water supplied to the cooling tower 1, a makeup water tank 15 is installed, and a water level sensor 16 and a water pump 17 are installed in the makeup water tank 15. The end of the pipe 18 connected to the discharge port side of the water pump 17 is branched into

pipes

19 and 20. One end of the pipe 19 is connected to the ball tap 21 of the pit 1d. The other end of the pipe 20 faces the pit 1d. A forced supply water valve 22 is provided in the pipe 20. The forced replenishment water valve 22 is controlled by a controller 23. The detection value of the electric conductivity meter 24 provided in the pit 1d is input to the controller 23.

Next, the operation of this cooling tower system will be described with reference to FIGS.

If the operation of circulating and supplying cold water from the cooling tower 1 to the heat exchanger 4 is continued, the water level in the pit 1d gradually decreases as the cooling water evaporates and the electrical conductivity gradually increases as shown in FIG. . When the electrical conductivity is increased to a predetermined intermediate value C _1, the pump 10 is started actuated by a signal from the controller 10a. The water supplied from the pump 10 passes through the turbidizer 11, is subjected to RO treatment by the RO device 13, the concentrated water is discharged out of the system, and the permeated water is introduced into the pit 1 d through the pipe 14.

The inflow of the permeate, increase in electric conductivity of the water in the pit 1d is slowed, but still continue the electrical conductivity increases further eventually reaches a predetermined upper limit value C _2. If it does so, the forced replenishment water valve 22 will be opened by the signal from the controller 23, and the replenishment water in the replenishment water tank 15 will be supplied in the pit 1d via the

piping

19 and 20. FIG. (The pump 17 is configured to operate when the forced replenishment water valve 22 and the ball tap 21 are open.) As a result, the water level in the pit 1d gradually rises and the electrical conductivity gradually increases. To drop. When the electrical conductivity of the cooling water in the pit 1d is lowered to a predetermined lower limit value C _0, forcing makeup water valve 22 while being closed, the water pump 17 is stopped.

Electrical conductivity of the water in the pit 1d is forced makeup water valve 22 is opened until drops to the lower limit value C _0, makeup water is continuously supplied during this time pits 1d. Thereby, the electrical conductivity gradually decreases. As the makeup water is supplied, the water level in the pit 1d rises as described above, but the water level rise in the pit 1d stops at the overflow water level (the level of the inlet 7a). After the water level in the pit 1d reaches the overflow water level, the same amount of pit water (cooling water) as the amount of makeup water flowing in via the

pipes

18 and 20 is overflowed until the forced makeup water valve 22 is closed. 7 flows into the blow water tank 8.

The water level in the blow water tank 8 rises with the inflow of this overflow water. The rise in the water level in the blow water tank 8 continues until the forced refill water valve 22 is closed.

As the forced replenishing water valve 22 is closed, the pump 10 stops and the water supply to the RO device 13 in the blow water tank 8 stops, so that the water level in the blow water tank 8 is kept constant thereafter. Be drunk. During this time, the electrical conductivity of the water in the pit 1d gradually increases, so that the above series of operations is repeated.

In FIG. 1, the electric conductivity meter 24 is installed, but a specific resistance meter is installed instead of the electric conductivity meter, and the specific resistance (or specific resistance and the water level of the blow tank) is measured by the specific resistance meter. Control may be performed based on this. In this case, when the specific resistance of the water in the pit 1d with the passage of operation of the cooling tower is reduced to a predetermined intermediate value R _1, the pump 10 starts operation by a signal from the controller 10a, the RO unit 13 Permeated water is introduced into the pit 1d.

The inflow of the permeate, the decrease of specific resistance of water in the pit 1d becomes slow, but still the resistivity further continued to fall, to eventually reach a predetermined lower limit value R _2. If it does so, the forced replenishment water valve 22 will be opened by the signal from the controller 23, and the replenishment water in the replenishment water tank 15 will be supplied in the pit 1d via the

piping

19 and 20. FIG. Thereby, the water level in the pit 1d gradually rises and the specific resistance gradually rises. When the specific resistance of the cooling water in the pit 1d rises to a predetermined upper limit value _R0 , the forced refill water valve 22 is closed and the water pump 17 is stopped.

As the specific resistance increases to the upper limit value R ₀ , the pump 10 stops and the water supply to the RO device 13 of the water in the blow water tank 8 also stops as the forced replenishment water valve 22 is closed. . Thereafter, the specific resistance of water in the pit 1d gradually decreases, so that the above series of operations is repeated.

The blow water discharged outside the system during the operation of this cooling tower system is only the concentrated water of the RO device 13, and the recovery rate of makeup water is high. In addition, since the pump 10 is ON / OFF controlled according to the electric conductivity or specific resistance of the cooling water, the control is simple. The pump 10 may be operated when the detected water level of the water level sensor 9 in the blow water tank 8 is equal to or higher than a predetermined upper limit value, and the pump 10 may be stopped when the detected water level is lower than a predetermined lower limit value. The upper limit is preferably about 60 to 80% of the full water level of the blow water tank 8, and the lower limit is preferably about 5 to 40% of the full water level.

As described above, when the water level in the pit 1d falls below a predetermined control value (the opening level of the ball tap 21) during the operation of the cooling tower system, the ball tap 21 is opened and the replenishment in the replenishing water tank 15 is performed. Water is supplied to the pit 1d through the ball tap 21. Although illustration is omitted, when the water level in the replenishing water tank 15 detected by the water level sensor 16 falls below a specified value, a water injection mechanism for injecting water such as industrial water, ground water or tap water into the replenishing water tank 15 is provided. Is provided.

In this embodiment, the slime or the scale inhibitor injected into the pit 1d is supplied to the RO device 13 through the turbidizer 11, so that the slime in the RO device 13 Scale prevention effect is also obtained.

The second embodiment will be described with reference to FIGS.

The configuration of the cooling tower 1 of this cooling tower system is the same as in FIG. 1, and the same reference numerals indicate the same parts.

The blow water tank 8 is provided with a water level sensor 9 and a first pump 10. A signal from the water level sensor 9 is input to the pump controller 10a, and the pump 10 is controlled by a signal from the pump controller 10a. Specifically, the pump 10 is activated when the detected water level of the water level sensor 9 is equal to or higher than a specified upper limit value, and the pump 10 is stopped when the detected water level is equal to or lower than the specified lower limit value. The upper limit is preferably about 60 to 80% of the full water level of the blow water tank 8, and the lower limit is preferably about 5 to 40% of the full water level.

Water supply from the pump 10 is supplied to the RO device 13 via the turbidifier 11 and the pipe 12.

The concentrated water of the RO device 13 is discharged out of the system, and the permeated water is introduced into the makeup water tank 15 through the pipe 14A. The replenishing water tank 15 is provided with a water level sensor 16 and a second pump 17. In this embodiment, the equipment from the blow water tank 8 to the replenishing water tank 15, the

water level sensors

9, 16 and the pump controller 10a constitute the recovery means.

The end of the pipe 18 connected to the discharge port side of the pump 17 is branched into

pipes

If the operation of circulating and supplying cold water from the cooling tower 1 to the heat exchanger 4 is continued, the water level in the pit 1d gradually decreases as the cooling water evaporates and the electrical conductivity gradually increases as shown in FIG. . When the electrical conductivity reaches the upper limit value D ₁ of the provision, by a signal from the controller 23, the forced supply of water valve 22 is opened, the pit 1d to supply water in the supply water tank 15 via a

pipe

19, 20 Supplied. The pump 17 is configured to operate when the forced replenishment water valve 22 and the ball tap 21 are open. As a result, the water level in the pit 1d gradually rises and the electrical conductivity gradually falls.

Force makeup water valve 22 is opened until the electrical conductivity of the water in the pit 1d is lowered to the lower limit value D ₀ of the provisions, makeup water is continuously supplied during this time pits 1d. As the makeup water is supplied, the water level in the pit 1d rises as described above, but the water level rise in the pit 1d stops at the overflow water level (the level of the inlet 7a). After the water level in the pit 1d reaches the overflow water level, the same amount of pit water (cooling water) as the amount of makeup water flowing in via the

pipes

With the inflow of overflow water, the water level in the blow water tank 8 rises. Then, when the water level in the blow water tank 8 reaches a prescribed upper limit value, the pump 10 starts to operate in response to a signal from the water level sensor 9. The water supplied from the pump 10 passes through the turbidizer 11, is subjected to RO treatment by the RO device 13, the concentrated water is discharged out of the system, and the permeated water is introduced into the makeup water tank 15. The pump 10 stops when the water level in the blow water tank 8 falls to a prescribed lower limit value.

Hereafter, this operation is repeated. The blow water discharged outside the system during operation of the cooling tower system is only the concentrated water of the RO device 13, and the recovery rate of makeup water is high. Moreover, since the pump 10 is ON / OFF controlled according to the water level in the blow water tank 8, the control is simple.

In the middle of the operation of the cooling tower system as described above, when the water level in the pit 1d falls below the specified control value (the opening level of the ball tap 21), the ball tap 21 is opened and the makeup water in the makeup water tank 15 is opened. Is supplied to the pit 1d through the ball tap 21.

Although not shown in the drawings, when the water level in the makeup tank 15 detected by the water level sensor 16 falls below a specified value, water injection such as industrial water, ground water or tap water is poured into the makeup tank 15. A mechanism is provided. This water injection mechanism also constitutes a collecting means.

The above embodiment is an example of the present invention, and the present invention may have a configuration other than the above. For example, a specific resistance meter may be installed instead of the electrical conductivity meter 24, and the opening / closing control of the forced replenishment water valve 22 may be performed based on the specific resistance measured by the specific resistance meter. In this case, when the specific resistance reaches the specified lower limit value, the forced supply water valve 22 is opened by a signal from the controller 23, and the forced supply water valve 22 is opened until the specific resistance rises to the specified upper limit value. During this time, makeup water continues to be supplied to the pit 1d. The other control contents are the same as when the electric conductivity meter 24 is used.

1 and 3 are examples of the present invention, and the present invention may be configured other than the above. For example, in the above embodiment, when the water level in the pit 1 d becomes higher than the inlet 7 a at the upper end of the overflow pipe 7, the cooling water higher than the inlet 7 a in the pit 1 d is blown through the overflow pipe 7. 8 is provided with a pipe line connecting the pipe 3 (especially the discharge side of the pump 2) and the blow water tank 8 and a valve installed in the pipe line to provide cooling water in the pit 1d. When the water level becomes higher than the specified water level (the water level at the inlet 7a), the valve opens, and cooling water higher than the specified water level in the pit 1d flows into the blow water tank 8 through the pipe line. Good.

Although the present invention has been described in detail using specific embodiments, it will be apparent to those skilled in the art that various modifications can be made without departing from the spirit and scope of the invention.
This application includes Japanese patent application 2017-038457 filed on March 1, 2017, Japanese patent application 2017-038458 filed on March 1, 2017, and Japanese patent application filed on February 2, 2018. Based on application 2018-017458 and Japanese patent application 2018-017460 filed on Feb. 2, 2018, which is incorporated by reference in its entirety.

DESCRIPTION OF SYMBOLS 1 Cooling tower 4 Heat exchanger 8 Blow water tank 13 RO apparatus 15 Replenishment water tank 24 Electric conductivity meter

Claims

A cooling tower connected to a cooling water circulation line;
Means for measuring the electrical characteristic value (electric conductivity or specific resistance) of the cooling water;
Recovery means for pumping water in the cooling tower to a reverse osmosis membrane device by a pump, and returning permeated water of the reverse osmosis membrane device to the cooling tower or a circulation line;
A cooling tower system comprising makeup water supply means for supplying makeup water according to at least one of the water level in the cooling tower and the electrical characteristic value,
A cooling tower system comprising control means for operating the recovery means in accordance with at least one of an electrical characteristic value of cooling water and a water level of the blow water tank.
In claim 1, as the recovery means,
A blow tank for receiving the overflow water;
The reverse osmosis membrane device for treating water pumped from the blow water tank;
A cooling tower system comprising: means for supplying permeated water of the reverse osmosis membrane device to the cooling tower or the circulation line.
According to claim 1, wherein the makeup water supply means, when the electric conductivity measured by the measuring means a predetermined elevated or when the resistivity to the upper limit value C 2 is lowered to a predetermined lower limit value R 2, electrical A cooling tower system, wherein makeup water is supplied until the conductivity decreases to a predetermined lower limit value C 0 or the specific resistance increases to a predetermined upper limit value R 0 .
In Claim 3, the control means increases the electrical conductivity of the cooling water to a predetermined intermediate value C 1 (where C 0 <C 1 <C 2 ), or the specific resistance is a predetermined intermediate value R 1 ( However, when it falls to R 2 <R 1 <R 0 ), the pump is started, and the electrical conductivity falls to the lower limit value C 0 or the specific resistance rises to the upper limit value R 0. Then, the cooling tower system characterized by stopping the pump.
5. The cooling tower system according to claim 1, wherein the water in the blow water tank is turbidized by a turbidity means and then supplied to the reverse osmosis membrane device.
A cooling tower system having a cooling tower and recovery means for treating overflow water of the cooling tower and recovering it as makeup water,
As the recovery means,
A blow tank for receiving the overflow water;
A reverse osmosis membrane device for treating water from the blow water tank;
A replenishing water tank for receiving the permeated water of the reverse osmosis membrane device;
Means for supplying water in the make-up water tank to the cooling tower as make-up water;
A cooling tower system comprising control means for operating the recovery means in accordance with the water level of the blow water tank or the water level of the blow water tank and the makeup water tank.
In Claim 6, the said control means is equipped with the water level sensor which detects the water level in the said blow water tank,
When the detected water level of the water level sensor rises to a prescribed upper limit value, the feed water pump to the reverse osmosis membrane device starts, and when the detected water level of the water level sensor falls to a prescribed lower limit value, the feed water pump stops. Cooling tower system characterized by
8. The cooling tower system according to claim 6, wherein water in the blow water tank is turbidized by a turbidity means and then supplied to the reverse osmosis membrane device.