JP7567599B2 - Water treatment system having a degassing device - Google Patents

Description

The present invention relates to a water treatment system having a degassing device.

Ion exchange devices that combine an ion exchange tower and a degasser, in which the water to be treated is treated in an ion exchange tower and then degassed in a degasser, or in the reverse order, in which the water is degassed in a degasser and then treated in an ion exchange tower, are widely used in pure water production systems. The degasser used in these systems is equipped with a structure that maintains the amount of water in a degassing water tank for storing the degassing tower effluent within a specified range, which is attached to the bottom of the degassing tower or separately installed downstream of the degassing tower.

In Patent Document 1, a flow control valve for the water to be treated is provided in the inlet piping of the degassing tower, and a liquid level detection means is provided in the degassing tank. By linking these together, the opening of the flow control valve is automatically adjusted according to the water level in the degassing tank, and the flow rate of the water to be treated to the degassing tower is controlled. In other words, when the water level in the degassing tank is high, the opening of the flow control valve is reduced to reduce the flow rate of the water to be treated to the degassing tower, and when the water level in the degassing tank is low, the opening of the valve is increased to increase the flow rate.

Publication number 3-56311

One type of degassing device is a scrubber type that has a spray nozzle installed at the top of the degassing tower to spray the water being treated as a mist. In the case of this type of degassing device, when the water level in the degassing tank is lower than a specified level, the opening of the flow control valve installed on the inlet side of the degassing tower automatically increases, so that a large amount of water being treated is fed to the spray nozzle and the water is sprayed from the spray nozzle as a mist, achieving high degassing performance. However, when the water level in the degassing tank is high, the opening of the flow control valve automatically decreases, causing the flow rate of the water to be treated to become excessively small, and the water is not sprayed from the spray nozzle as a mist, but rather the tiny droplets clump together, which can result in reduced degassing performance.

The present invention aims to provide a water treatment system that can maintain the degassing performance of the degassing device and operate stably, regardless of the operating conditions of the water treatment device subsequent to the degassing device.

The water treatment system of the present invention comprises a degassing device through which water is passed by a water supply means, a return line capable of returning a portion of the treated water downstream of the degassing device from the downstream side of the degassing device to the upstream side of the degassing device, and a control device that controls the water supply means so that the water supply flow rate to the degassing device is within a predetermined range and controls the excess treated water to be returned via the return line.

In one aspect of the present invention, the control device controls the water supply means so that the water supply flow rate to the degassing device is within a predetermined range based on the measurement value of a flowmeter that measures the flow rate of the treated water and is provided in the treated water line through which the treated water flows, and controls so that the excess treated water is returned through the return line.

In one aspect of the present invention, the control device controls the water supply means so that the water supply flow rate to the deaeration device is within a predetermined range based on the measurement value of a water level gauge that is provided in the treatment water tank in which the treatment water is stored and measures the water level in the tank, and controls so that the excess of the treatment water is returned through a return line.

In one aspect of the present invention, the control device controls the water supply means so that the water supply flow rate to the degassing device is within a predetermined range based on the measurement value of a flowmeter that is provided in an extraction line through which treated water is extracted from the treatment water tank and measures the extraction flow rate of the treated water, and controls so that the excess treated water is returned through a return line.

In one embodiment of the present invention, an ion exchange tower is provided at least downstream of the degassing device.

In one embodiment of the present invention, a pH adjustment means is provided upstream of the degassing device.

In one embodiment of the present invention, the degassing device is a scrubber-type decarbonation tower equipped with a lower water tank.

In one aspect of the present invention, the water supply means is a raw water pump, and a water supply pump is provided downstream of the deaeration device, and the discharge flow rate of the water supply pump is equal to or greater than the discharge flow rate of the raw water pump.

The water treatment system of the present invention can stably operate the water treatment system by continuously operating the degassing device and performing sufficient degassing, regardless of the operating status of the water treatment device subsequent to the degassing device, such as the decarbonation tower (such as a temporary shutdown of the equipment due to the treatment water tank being full).

1 is a configuration diagram of a water treatment system according to an embodiment.

The embodiment will be described below with reference to FIG.

Raw water is introduced into raw water tank 1 and passed through H-type cation exchange tower (hereinafter referred to as H tower) 3 by raw water pump 2, and the cation exchange treated water is then passed through scrubber-type decarbonation tower 4, which has a lower water tank in this embodiment as a degassing device. The decarbonation treated water is passed through OH-type anion exchange tower (hereinafter referred to as OH tower) 6 by water supply pump 5, and the anion exchange treated water is then introduced into treated water tank 10 as final treated water via treated water line 7, three-way valve 8, and treated water line 9. The final treated water in treated water tank 10 is withdrawn through an withdrawal line having withdrawal pump 11 and sent to the next process.

In this embodiment, the treated water downstream of the degassing device (hereinafter, simply referred to as treated water) refers to decarbonation treated water, anion exchange treated water, and final treated water.

In addition, in this embodiment, a return line 12 is provided to return a portion of the anion exchange treated water from the three-way valve 8 to the upstream side of the decarbonation tower 4 (in this embodiment, the raw water tank 1). Although not shown, a pH adjustment means may be provided between the raw water pump 2 and the decarbonation tower 4.

In a water treatment system configured in this manner, the discharge water volume of the raw water pump 2 is controlled by the control device 13 so that it is equal to or greater than a specified water volume (the water volume at which a specified degassing performance is achieved in the decarbonation tower 4. This degassing performance depends on the water volume), and water is continuously sent from the raw water tank 1 to the decarbonation tower 4, thereby achieving sufficient decarbonation in the decarbonation tower 4. Specifically, the control is performed as follows.

That is, the amount of excess water out of the amount of treated water (the amount of anion exchange treated water from the OH tower 6) is calculated based on the flow rate detected by a flow meter installed on the treated water line 7 or the withdrawal line, or the water level detected by a water level meter installed in the treated water tank 10. This excess water is then diverted by the three-way valve 8 and returned to the raw water tank 1 via the return line 12. When there is no excess amount of treated water, the entire amount of anion exchange treated water from the OH tower 6 is sent to the treated water tank 10.

Note that the rated discharge volume of the raw water pump 2 may be greater than the rated discharge volume of the water supply pump 5. (In a typical water treatment system, the amount of water decreases in later stages, so pumps of equal or greater capacity are rarely installed in later stages.) In this case, the water level in the lower tank of the decarbonation tower 4 gradually rises, so the water supply to the decarbonation tower 4 is temporarily stopped to lower the water level in the lower tank. In this case, by operating the raw water pump intermittently, the water supply flow rate to the decarbonation tower can be maintained high when the raw water pump 1 is operating.

To avoid such intermittent operation of the raw water pump, it is preferable to use a water supply pump 5 with a rated discharge volume equal to or greater than that of the raw water pump 2. When the water level in the lower tank of the decarbonation tower 4 decreases, the discharge volume of the water supply pump 5 is reduced.

In this way, this water treatment system can reduce the risk of insufficient water intake and treated water quality not reaching the required level due to carbonate ion load in water treatment equipment after the decarbonation tower.

In this embodiment, H tower 3 and OH tower 4 are installed, but H tower 3 may be omitted and a mixed bed ion exchange tower installed instead of OH tower 4. Also, if there is a mechanism for adjusting pH downstream of raw water pump 2, the ion exchange tower may be omitted. Also, instead of three-way valve 8, valves may be provided on lines 9 and 12.

1 Raw water tank 4 Decarbonation tower (degassing device)
8 Three-way valve 12 Return line 13 Control device

Claims (6)

A deaeration device comprising a scrubber type decarbonation tower having a lower water tank, through which water is passed by a water supply means;
a return line capable of returning a portion of the treated water downstream of the degassing device from the downstream side of the degassing device to the upstream side of the degassing device;
A water treatment system including a control device that controls the water supply means so that the water supply flow rate to the deaeration device is within a predetermined range and controls the excess of the treated water to be returned through a return line,
The control device controls the water supply means so that the water supply flow rate to the degassing device is within a predetermined range based on the measurement value of a flow meter that measures the flow rate of the treated water and is installed in the treated water line through which the treated water flows, and controls the water treatment system so that the excess treated water is returned through a return line. A deaeration device comprising a scrubber type decarbonation tower having a lower water tank, through which water is passed by a water supply means;
a return line capable of returning a portion of the treated water downstream of the degassing device from the downstream side of the degassing device to the upstream side of the degassing device;
A water treatment system including a control device that controls the water supply means so that the water supply flow rate to the deaeration device is within a predetermined range and controls the excess of the treated water to be returned through a return line,
The control device is a water treatment system in which the control means controls the water supply means so that the water supply flow rate to the degassing device is within a predetermined range based on the measurement value of a water level gauge that is installed in the treatment water tank in which the treatment water is stored and measures the water level in the tank, and controls the return of excess treated water through a return line. A deaeration device comprising a scrubber type decarbonation tower having a lower water tank, through which water is passed by a water supply means;
a return line capable of returning a portion of the treated water downstream of the degassing device from the downstream side of the degassing device to the upstream side of the degassing device;
A water treatment system including a control device that controls the water supply means so that the water supply flow rate to the deaeration device is within a predetermined range and controls the excess of the treated water to be returned through a return line,
The control device is provided in an extraction line through which treated water is extracted from a treatment water tank, and based on the measurement value of a flow meter which measures the extraction flow rate of the treated water, controls the water supply means so that the water supply flow rate to the degassing device is within a predetermined range, and controls the return of excess treated water through a return line. The water treatment system according to any one of claims 1 to 3 , further comprising an ion exchange tower at least downstream of the degassing device. 5. The water treatment system according to claim 1, further comprising a pH adjusting means provided upstream of the degassing device. 6. The water treatment system according to claim 1 , wherein the water supply means is a raw water pump, and a water supply pump is provided downstream of the deaeration device, and the discharge flow rate of the water supply pump is equal to or greater than the discharge flow rate of the raw water pump.

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