JP2015116555A - Removal device of dissolved oxygen - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology that achieves downsizing of a nitrogen-substitution-type deoxidation device for removal of dissolved oxygen in water, and efficiently gives stably-deoxidized sea water or fresh water.SOLUTION: A deoxidation device reduces/removes dissolved oxygen in water by generating nanobubbles of nitrogen gas in water and substituting dissolved oxygen in water with nitrogen, in removing the dissolved oxygen in fresh water or sea water. The removal device of dissolved oxygen includes an injection unit for injecting nitrogen gas into water to be treated, and a laminate of a plurality of plates having a plurality of holes arranged on a plane through which the nitrogen-injected water to be treated flows and having a top face groove and a bottom face groove crossing at the hole along the hole arrangement.

Description

The present invention relates to an apparatus for removing dissolved oxygen in water or seawater. In particular, the present invention relates to a nitrogen substitution type deoxygenation apparatus and a nitrogen substitution type deoxygenation method by substituting and removing oxygen dissolved in water and seawater with nitrogen gas nanobubbles. More specifically, the present invention relates to a nitrogen-substitution-type deoxygenation apparatus and a nitrogen-substitution-type deoxygenation method applicable to boiler water, cooling circulating water, drinking water, industrial seawater, and the like.
The present invention relates to a gas-liquid contact method based on a stripping technique for removing dissolved oxygen in water by replacing it with an inert gas such as nitrogen, and a water deoxygenation method using the same. The present invention relates to a dissolved oxygen removing apparatus for removing dissolved oxygen contained in raw water.

In the water treatment field such as boiler water, cooling circulating water, drinking water, industrial seawater, etc., boilers, ancillary equipment, steam piping, steam using equipment, drain (condensed water) recovery piping, cooling equipment, etc. depending on dissolved oxygen in the water Corrosion may occur, and may cause major problems such as equipment failures and serious accidents. In order to prevent such problems, in the field of water treatment such as boiler water, cooling circulating water, and drinking water, a deoxygenator is used to remove dissolved oxygen in the water, or dewatering is performed in boiler feed water. Measures such as injecting oxygen agent are taken.

As a deoxygenation device, a membrane deoxygenation device, a vacuum deoxygenation device, a nitrogen substitution deoxygenation device and the like are generally known. The membrane deoxygenation device is a device that reduces dissolved oxygen contained in water to be treated by using a specific polymer membrane. The vacuum deoxygenation apparatus is an apparatus for reducing dissolved oxygen contained in the water to be treated by spraying the water to be treated from the upper part to the lower part in the treatment tank and vacuuming the inside of the treatment tank. It is.

Further, the nitrogen substitution type deoxygenation device is a device that supplies nitrogen gas to the water to be treated and replaces the dissolved oxygen contained in the water to be treated with nitrogen for reduction. In recent years, technical development relating to this nitrogen substitution type deoxygenation apparatus has been advanced.

By connecting the raw water in the raw water tank to the raw water supply system that sends out the raw water with a supply pump, and contacting the nitrogen gas supplied from the nitrogen gas source through the gas supply system with the raw water supplied through the raw water supply system, Deoxygenation device main body that removes oxygen from raw water, and treated water pump from the water supply pump in the water supply system to supply the treated water that has been deoxygenated by the deoxygenation device main body to the raw water consumption unit Increase the amount of treated water supplied to the upstream side and the amount of treated water supplied to the feed water system from the amount of raw water used in the raw water consumption section, and part of the treated water is upstream from the treated water confluence in the feed water system. And a control unit that controls the capacity of the treated water pump so that the amount of the treated water returned to the raw water tank is maintained within a predetermined range. There is no excess or deficiency Physical water can be supplied, equipment operation cost excellent nitrogen type deoxygenator economical capable of suppressing cheap is disclosed (see Patent Document 1).

In addition, a nitrogen injection means for injecting nitrogen gas into the water supply pipe, a static mixer for turbulent mixing of the water into which the nitrogen gas has been injected, and a gas-liquid separation means for gas-liquid separation of the turbulent mixed water are provided. Thus, a deoxygenation apparatus that can save energy and has excellent deoxygenation efficiency is disclosed (see Patent Document 2).

Further, in the deoxygenation tower rising vertically, the water to be treated going from the upper side to the lower side is brought into contact with the nitrogen supplied from the lower side and going upward, and the deoxygenated water is supplied to the tank from the lower part of the tower. There has been proposed a deoxygenation device that exhausts nitrogen gas containing oxygen from the upper part of the gas generator. In this deoxygenation device, the water in the tank is circulated and the makeup water is supplied to the inlet of the deoxygenation tower, so that the deoxygenation tower can be provided without significant reinforcement in the water supply tank. Has been devised so that deoxygenated water can be supplied directly to the water supply tank (see Patent Document 3).

In order to provide a novel technique capable of realizing downsizing of a nitrogen substitution type deoxygenation apparatus and obtaining stable deoxygenated water efficiently, by replacing dissolved oxygen in water with nitrogen, A deoxygenation apparatus for reducing dissolved oxygen of the nitrogen gas injection unit for injecting nitrogen gas into the water to be treated and a bellows-shaped water pipe for passing the water to be treated into which the nitrogen gas has been injected. A nitrogen substitution type deoxygenation apparatus is provided. According to the nitrogen substitution type deoxygenation device, it has been proposed that an efficient and stable deoxygenated water can be obtained by using a bellows-shaped water pipe, despite an extremely space-saving device (patent) Reference 4).

Further, in the nitrogen substitution-multistage contact method considered to be practical for general industrial use, even if three or more stages are performed, the nitrogen consumption does not decrease so much, and there is a limit to the reduction of nitrogen consumption. Since this gas-liquid contact method can completely eliminate the supersaturation of dissolved gas in each stage, it has been proposed that the nitrogen consumption close to the theoretical efficiency can be suppressed even in a multistage process of three or more stages (patent) Reference 5).

Furthermore, in order to provide a nitrogen-replacement-type dissolved oxygen removing apparatus that can efficiently remove dissolved oxygen contained in raw water, the dissolved oxygen removing apparatus includes a nitrogen gas generating means for generating nitrogen gas, A first gas-liquid mixing tank for mixing raw water with nitrogen gas in a pressurized state, and a first gas-liquid separating the gas-liquid mixed water obtained in the first gas-liquid mixing tank by reducing the pressure A separation tank, a first pump for pressurizing and transferring the treated water separated in the first gas-liquid separation tank, and a second for mixing the treated water transferred by the first pump with nitrogen gas A gas-liquid mixing tank and a second gas-liquid separation tank for separating the gas-liquid mixed water obtained in the second gas-liquid mixing tank by depressurizing and gas-liquid separation have been proposed (Patent Literature) 6).

Environment-friendly and human-friendly reduction potential water-rich energy-saving production method that eliminates the neutralization process and mass-produces hydrogen gas in neutral water with high efficiency. For the purpose of providing a dissolved hydrogen-reduced water production apparatus capable of generating water, the dissolved hydrogen-reduced water production apparatus has one or more orifice plates each having a through hole with a diameter of 1 mm to 6 mm as a spacer ring. An alternately assembled gas-liquid mixing device has been proposed (see Patent Document 7).

As described above, the technical development related to the nitrogen substitution type deoxygenation apparatus has been progressing, but there has been a problem that the apparatus becomes larger. There is a problem that the device configuration is complicated and the height of the device is increased. Moreover, when installing in the existing tank retrofit, installation was complicated and there existed a subject that application was restrict | limited. In addition to the increase in the size of the apparatus, there is also a problem that the oxygen in the outside air is dissolved again and the dissolved oxygen concentration is increased when the deoxygenated water supplied to the tank comes into contact with the outside air on the water surface. .

JP 2009-279466 A JP 2001-129304 A JP 2010-7866 A JP 2011-230031 A JP 2013-13847 A JP 2008-264686A JP 2007-330958 A

As described above, technical development related to nitrogen substitution type deoxygenation equipment is underway, but there are still problems to be solved, such as the problem of enlargement of the equipment and the problem that the concentration of dissolved oxygen increases depending on the construction of the equipment. It is the actual situation that has.

Accordingly, it is a main object to provide a novel technique capable of realizing downsizing of a nitrogen substitution type deoxygenation apparatus and obtaining stable and deoxygenated seawater or water efficiently.

When considering a deoxygenation method, if the water quality is clean, a membrane deaerator is advantageous in consideration of treatment efficiency, operation at a partial load, and the need for a replacement gas such as nitrogen. However, in the water quality used for general industrial use, there is a restriction that the performance of the membrane deteriorates due to seawater or various impurities contained in the water, and that it cannot be used with hot water, and its spread is extremely limited.

Therefore, in a general industrial-level deoxygenation process, a multistage contact method by nitrogen substitution using seawater gas stripping technology used in the industry is advantageous. The purpose of this invention is to provide a gas stripping device that is inexpensive and has high performance by reducing the processing efficiency associated with a decrease in the amount of replacement gas in the multistage contact method of gas replacement and making the device compact while improving it.

Deoxygenation device that reduces and removes dissolved oxygen in water by removing nitrogen dissolved in water by replacing nitrogen dissolved in water in a nanobubble state when removing dissolved oxygen in water or seawater A plurality of holes are arranged in a plate having a nitrogen gas injection part for injecting nitrogen gas into the water to be treated and a plane through which the water to be treated into which nitrogen gas has been injected is passed, and the arrangement of the holes Disposed with a groove that crosses the upper and lower surfaces in the direction, a stack of multiple plates, and a unit that consists of a plate flat plate sandwiched from the upper and lower surfaces so that the plate with the holes does not interfere It is an oxygen removing device.

The plate in the device containing the plate stack is 3 to 20 mm thick, with 10 to 500 co-arranged holes and grooves, and the area ratio of the holes / grooves Is 2 to 100, the hole diameter is 2 to 30 mm, and the shape of the hole is circular, triangular, quadrangular, polygonal, conical, two-stage cylindrical, cylindrical conical In order to be able to mix seawater or water efficiently by the venturi effect by the groove jet for supplying nitrogen gas and seawater or water, the upper surface groove and the lower surface groove intersect from the groove part toward the inside of the circle, and from the groove part The jetted treated water is efficiently mixed, dispersed, homogenized and refined.

The angle of the hole arrangement of the plate is appropriately determined according to the physical properties of the treated water to be passed and the target dissolved oxygen amount, and is arranged within 0 to 180 degrees. The hole arrangement of the plate The number of holes that pass through the hole array can be determined from 1 to 500 or more depending on the treatment amount and dissolved oxygen amount according to the purpose. In such a case, it is possible to connect them in parallel. In addition, the pitch of the holes in the plate can be appropriately determined between the hole diameter plus 0.5 mm to 10 mm according to the processing amount and the dissolved oxygen amount.

The plate accommodated in the mixing container is a square, rectangle, or circle having a size of 30 to 1000 mm as a shape, made of a highly corrosive resin or metal alloy, and is a single plate. A flat plate is sandwiched from above and below to form a unit, and the unit is used in a stack of 2 to 100 sheets. When the target processing capacity is large, it is possible to connect 2 to 100 unit modules linked in parallel.

The nitrogen gas is introduced at a flow rate of 0.3 to 5 m / s in the plate for injecting nitrogen gas at a flow rate of 0.005 to 1 Nm ³ or more per 1 m ³ of seawater or fresh water.

Nitrogen gas is pumped by seawater or fresh water taken from the suction side of the pressurization pump by the pressurization pump, and mixed into the micronizer mixed solution containing side at a flow rate of 50 to 1000 L / min to make fine particles. It has a wall for injecting from a groove orifice in a plate disposed inside the container and generating cavitation efficiently inside the hole, and making the fluid turbulent.

According to the present invention, it is possible to obtain efficient and stable deoxygenated water by using the groove portion of the plate having holes, despite the extremely space-saving device. Technological development related to the nitrogen substitution type deoxygenation device is underway, but the concentration of dissolved oxygen in seawater could be reduced depending on the size of the device and the configuration of the device.

When considering a deoxygenation method, if the water quality is clean, a membrane deaerator is advantageous in consideration of treatment efficiency, operation at a partial load, and the need for a replacement gas such as nitrogen. However, in the water quality used for general industrial use, there is a restriction that the performance of the membrane deteriorates due to seawater or various impurities contained in the water, and that it cannot be used with hot water, and its spread is extremely limited.

Therefore, in the general industrial level deoxygenation process, a multi-stage contact method by nitrogen substitution using gas stripping technology is advantageous. An object of the present invention is to provide a gas stripping apparatus that is inexpensive and has high performance by reducing the processing efficiency associated with a decrease in the amount of replacement gas in the multistage contact method of gas replacement, and making the apparatus compact while improving it.

  Schematic diagram of dissolved oxygen removal device   Plate shape A Top view B Bottom view C Front view D Plan view   Plate hole arrangement A arrangement and angle view B plate hole cross section   Detailed view of plate holes and grooves   Plate hole fluid condition diagram A plan view B hole fluid condition front view   Plate unit diagram A unit diagram B unit stacking diagram   Stacking unit square storage diagram A front view B schematic diagram   Stacking unit circular storage diagram A front view B schematic diagram   Implementation equipment diagram

A nitrogen substitution type deoxygenation method according to the present invention is a deoxygenation method for reducing dissolved oxygen in water by substituting dissolved oxygen in water with nitrogen, comprising a nitrogen gas injection step and a water flow step. It is at least a method to do. Moreover, it is also possible to perform a flow rate adjustment process etc. as needed. Hereinafter, each step will be described in detail.

(1) Nitrogen gas injection process The nitrogen gas injection process is a process of injecting nitrogen gas into the water to be treated. The nitrogen gas injection method performed in the nitrogen gas injection step is not particularly limited, and any method usually used in the nitrogen substitution deoxygenation technical field can be freely selected and used. For example, a method of injecting nitrogen gas by press-fitting into the circulation line of water to be treated, a method of inhaling using an ejector, etc., and a method of injecting nitrogen gas such as efficient injection by negative pressure on the suction side of the pump And so on.

Note that when nitrogen gas is injected by press-fitting, it is preferable to make the bubbles of the nitrogen gas fine. This is because the nitrogen gas can be made uniform quickly in the water to be treated.

The amount of nitrogen gas injected in the nitrogen gas injection step can be freely set according to the dissolved oxygen concentration and purpose of the water to be treated. In the present invention, in order to further lower the dissolved oxygen in the treated water, it is preferable to inject nitrogen gas at 0.005 Nm ³ or more per 1 m ^{3 of} water flow rate.

(2) Water flow process The water flow process is a process in which water to be treated after passing through the nitrogen gas injection process is pressurized with a pressure pump and passed through the plate. The water to be treated into which nitrogen gas has been injected in the nitrogen gas injecting step is converted into nano-scaled nitrogen in this water passing step, and replacement of dissolved oxygen with nitrogen in the water to be processed is performed.

The flow rate of the water to be treated in the water flow process is not particularly limited, and can be freely set as long as the object of the present invention is not impaired. In the present invention, the water flow is particularly preferably adjusted to 0.3 to 8 m / s, and more preferably 0.5 to 5 m / s. By setting it to 0.3 m / s or more, substitution of dissolved oxygen and nitrogen becomes efficient. Moreover, a pressure loss can be suppressed by setting it as 5 m / s or less.

The flow rate of the water to be treated can be adjusted in a flow rate adjusting step described later, but can also be adjusted by selecting the diameter of the pipe according to the amount of water to be treated.

(3) Flow rate adjustment process The flow rate adjustment process is a process of adjusting the flow rate in the water flow process. In this flow rate adjusting step, it is possible to adjust the pressure together with the flow rate adjustment. This flow rate adjustment step is not essential in the nitrogen substitution-type deoxygenation method according to the present invention, but in order to more efficiently replace dissolved oxygen and nitrogen, the flow rate adjustment step is performed to obtain a predetermined flow rate and It is preferable to adjust the pressure.

In the nitrogen substitution type deoxygenation method according to the present invention, the order in which the flow rate adjustment step is performed is not particularly limited. If the flow rate in the water flow step can be adjusted, the order in which the other steps of the nitrogen substitution type deoxygenation method can be freely performed. Can be done. In the present invention, it is particularly preferable to carry out after the nitrogen gas injection step. This is because the dissolved oxygen in the treated water can be further reduced by performing the flow rate adjusting step after performing the nitrogen gas injection step. For example, a method of performing a flow rate adjustment step immediately after performing the nitrogen gas injection step, a method of performing a flow rate adjustment step after performing the water flow step, a method of simultaneously performing the water flow step and the flow rate adjustment step, etc. It is also possible to use this method.

In the flow rate adjustment step, the flow velocity and pressure to be adjusted can be appropriately determined according to the purpose. In the present invention, the flow rate is preferably adjusted to 0.5 to 5 m / s, more preferably 0.5 to 5 m / s with respect to the plate groove. Further, the pressure is preferably adjusted so that the pressure in the immediate vicinity of the plate entrance is 0.05 to 0.6 MPa.

Hereinafter, the present invention will be described in more detail based on examples, and effects of the present invention will be verified. In addition, the Example demonstrated below shows an example of the typical Example of this invention, and, thereby, the range of this invention is not interpreted narrowly.

Round plate diameters of 4 mm holes are arranged in 5 rows in the array method, groove widths from 0.8 mm to 1 mm and groove depths of 2 mm. 1 unit was used, 9 units were stacked, and a space was further provided. Then, they were housed in a sealed casing having only an inlet and an outlet. The pump used a submersible pump of 0.4 Kw-100V, and nitrogen gas was injected and mixed from the suction side of the submersible pump, and the gas capacity was set to 2.5 L / min via a flow meter. The tank capacity is 100L.

A round plate of 5mm holes is arranged in 5 rows, a width of 0.8mm to 1mm, and a solid plate plate of the same dimensions as a plate constructed with a groove depth of 2mm. 1 unit was used, 9 units were stacked, and a space was further provided. Then, they were housed in a sealed casing having only an inlet and an outlet. The pump used a submersible pump of 0.4 Kw-100V, and nitrogen gas was injected and mixed from the suction side of the submersible pump, and the gas capacity was set to 2.5 L / min via a flow meter. The tank capacity is 100L.

A round plate of holes with 6 mm holes arranged in 5 rows, a groove width of 0.8 mm to 1 mm, and a solid plate with the same dimensions as a plate with a groove depth of 2 mm, 1 unit was used, 9 units were stacked, and a space was further provided. Then, they were housed in a sealed casing having only an inlet and an outlet. The pump used a submersible pump of 0.4 Kw-100V, and nitrogen gas was injected and mixed from the suction side of the submersible pump, and the gas capacity was set to 2.5 L / min via a flow meter. The tank capacity is 100L.

A round plate of holes with 6 mm holes arranged in 5 rows, a groove width of 0.8 mm to 1 mm, and a solid plate with the same dimensions as a plate with a groove depth of 2 mm, 1 unit was used, 9 units were stacked, and a space was further provided. Then, they were housed in a sealed casing having only an inlet and an outlet. The pump used a submersible pump of 0.4 Kw-100V, and nitrogen gas was injected and mixed from the suction side of the submersible pump, and the gas capacity was set to 2.5 L / min via a flow meter. The tank capacity is 100L. The groove angle is 60 degrees.

As shown in Table 1, it was found that the transition of the dissolved oxygen amount dramatically improved the deoxygenation effect when a 6 mm plate was used.

1. 1. Dissolved oxygen removing device Plate 3. 3. Mixer 4. Pressure pump Nitrogen gas 6. Seawater or fresh water 7. Plate hole for mixer 8. Mixer plate top groove 9. 9. Mixer plate bottom surface groove 10. Fluid flow in the top groove of the mixer plate 11. Fluid flow in the bottom groove of the mixer plate Groove shape width 13. Groove shape depth 14. Hole array angle 15. Plate unit lamination 16. Installation in plate unit casing 17. Fluid flow 18. Casing 19. Mixture inlet 20. Gas injection part 21. Implementation test apparatus 22. Mixer gap 23. Connecting gap 24. Valve 25. Cavity 26. Mixture outlet 27. Flat plate for plate

The present invention relates to an apparatus for removing dissolved oxygen in water or seawater. In particular, the present invention relates to a nitrogen substitution type deoxygenation apparatus and a nitrogen substitution type deoxygenation method by substituting and removing oxygen dissolved in water and seawater with nitrogen gas nanobubbles. More specifically, the present invention relates to a nitrogen-substitution-type deoxygenation apparatus and a nitrogen-substitution-type deoxygenation method applicable to boiler water, cooling circulating water, drinking water, industrial seawater, and the like.
The present invention relates to a gas-liquid contact method based on a stripping technique for removing dissolved oxygen in water by replacing it with an inert gas such as nitrogen, and a water deoxygenation method using the same.
The present invention relates to a dissolved oxygen removing apparatus for removing dissolved oxygen contained in raw water.

In the water treatment field such as boiler water, cooling circulating water, drinking water, industrial seawater, etc., boilers, ancillary equipment, steam piping, steam using equipment, drain (condensed water) recovery piping, cooling equipment, etc. depending on dissolved oxygen in the water Corrosion may occur, and may cause major problems such as equipment failures and serious accidents. In order to prevent such problems, in the field of water treatment such as boiler water, cooling circulating water, and drinking water, a deoxygenator is used to remove dissolved oxygen in the water, or dewatering is performed in boiler feed water. Measures such as injecting oxygen agent are taken.

As a deoxygenation device, a membrane deoxygenation device, a vacuum deoxygenation device, a nitrogen substitution deoxygenation device and the like are generally known. The membrane deoxygenation device is a device that reduces dissolved oxygen contained in water to be treated by using a specific polymer membrane.
The vacuum deoxygenation apparatus is an apparatus for reducing dissolved oxygen contained in the water to be treated by spraying the water to be treated from the upper part to the lower part in the treatment tank and vacuuming the inside of the treatment tank. It is.

Further, the nitrogen substitution type deoxygenation device is a device that supplies nitrogen gas to the water to be treated and replaces the dissolved oxygen contained in the water to be treated with nitrogen for reduction. In recent years, technical development relating to this nitrogen substitution type deoxygenation apparatus has been advanced.

By connecting the raw water in the raw water tank to the raw water supply system that sends out the raw water with a supply pump, and contacting the nitrogen gas supplied from the nitrogen gas source through the gas supply system with the raw water supplied through the raw water supply system, Deoxygenation device main body that removes oxygen from raw water, and treated water pump from the water supply pump in the water supply system to supply the treated water that has been deoxygenated by the deoxygenation device main body to the raw water consumption unit Increase the amount of treated water supplied to the upstream side and the amount of treated water supplied to the feed water system from the amount of raw water used in the raw water consumption section, and part of the treated water is upstream from the treated water confluence in the feed water system. And a control unit that controls the capacity of the treated water pump so that the amount of the treated water returned to the raw water tank is maintained within a predetermined range. There is no excess or deficiency Physical water can be supplied, equipment operation cost excellent nitrogen type deoxygenator economical capable of suppressing cheap is disclosed (see Patent Document 1).

In addition, a nitrogen injection means for injecting nitrogen gas into the water supply pipe, a static mixer for turbulent mixing of the water into which the nitrogen gas has been injected, and a gas-liquid separation means for gas-liquid separation of the turbulent mixed water are provided. Thus, a deoxygenation apparatus that can save energy and has excellent deoxygenation efficiency is disclosed (see Patent Document 2).

Further, in the deoxygenation tower rising vertically, the water to be treated going from the upper side to the lower side is brought into contact with the nitrogen supplied from the lower side and going upward, and the deoxygenated water is supplied to the tank from the lower part of the tower. There has been proposed a deoxygenation device that exhausts nitrogen gas containing oxygen from the upper part of the gas generator. In this deoxygenation device, the water in the tank is circulated and the makeup water is supplied to the inlet of the deoxygenation tower, so that the deoxygenation tower can be provided without significant reinforcement in the water supply tank. Has been devised so that deoxygenated water can be supplied directly to the water supply tank (see Patent Document 3).

In order to provide a novel technique capable of realizing downsizing of a nitrogen substitution type deoxygenation apparatus and obtaining stable deoxygenated water efficiently, by replacing dissolved oxygen in water with nitrogen, A deoxygenation apparatus for reducing dissolved oxygen of the nitrogen gas injection unit for injecting nitrogen gas into the water to be treated and a bellows-shaped water pipe for passing the water to be treated into which the nitrogen gas has been injected. A nitrogen substitution type deoxygenation apparatus is provided. According to the nitrogen substitution type deoxygenation device, it has been proposed that an efficient and stable deoxygenated water can be obtained by using a bellows-shaped water pipe, despite an extremely space-saving device (patent) Reference 4).

Further, in the nitrogen substitution-multistage contact method considered to be practical for general industrial use, even if three or more stages are performed, the nitrogen consumption does not decrease so much, and there is a limit to the reduction of nitrogen consumption. Since this gas-liquid contact method can completely eliminate the supersaturation of dissolved gas in each stage, it has been proposed that the nitrogen consumption close to the theoretical efficiency can be suppressed even in a multistage process of three or more stages (patent) Reference 5).

Furthermore, in order to provide a nitrogen-replacement-type dissolved oxygen removing apparatus that can efficiently remove dissolved oxygen contained in raw water, the dissolved oxygen removing apparatus includes a nitrogen gas generating means for generating nitrogen gas, A first gas-liquid mixing tank for mixing raw water with nitrogen gas in a pressurized state, and a first gas-liquid separating the gas-liquid mixed water obtained in the first gas-liquid mixing tank by reducing the pressure A separation tank, a first pump for pressurizing and transferring the treated water separated in the first gas-liquid separation tank, and a second for mixing the treated water transferred by the first pump with nitrogen gas A gas-liquid mixing tank and a second gas-liquid separation tank for separating the gas-liquid mixed water obtained in the second gas-liquid mixing tank by depressurizing and gas-liquid separation have been proposed (Patent Literature) 6).

Environment-friendly and human-friendly reduction potential water-rich energy-saving production method that eliminates the neutralization process and mass-produces hydrogen gas in neutral water with high efficiency. For the purpose of providing a dissolved hydrogen-reduced water production apparatus capable of generating water, the dissolved hydrogen-reduced water production apparatus has one or more orifice plates each having a through hole with a diameter of 1 mm to 6 mm as a spacer ring. An alternately assembled gas-liquid mixing device has been proposed (see Patent Document 7).

As described above, the technical development related to the nitrogen substitution type deoxygenation apparatus has been progressing, but there has been a problem that the apparatus becomes larger. There is a problem that the device configuration is complicated and the height of the device is increased. Moreover, when installing in the existing tank retrofit, installation was complicated and there existed a subject that application was restrict | limited. In addition to the increase in the size of the apparatus, there is also a problem that the oxygen in the outside air is dissolved again and the dissolved oxygen concentration is increased when the deoxygenated water supplied to the tank comes into contact with the outside air on the water surface. .

JP 2009-279466 A JP 2001-129304 A JP 2010-7866 A JP 2011-230031 A JP 2013-13847 A JP 2008-264686A JP 2007-330958 A

As described above, technical development related to nitrogen substitution type deoxygenation equipment is underway, but there are still problems to be solved, such as the problem of enlargement of the equipment and the problem that the concentration of dissolved oxygen increases depending on the construction of the equipment. It is the actual situation that has.

Accordingly, it is a main object to provide a novel technique capable of realizing downsizing of a nitrogen substitution type deoxygenation apparatus and obtaining stable and deoxygenated seawater or water efficiently.

When considering a deoxygenation method, if the water quality is clean, a membrane deaerator is advantageous in consideration of treatment efficiency, operation at a partial load, and the need for a replacement gas such as nitrogen. However, in the water quality used for general industrial use, there is a restriction that the performance of the membrane deteriorates due to seawater or various impurities contained in the water, and that it cannot be used with hot water, and its spread is extremely limited.

Therefore, in a general industrial-level deoxygenation process, a multistage contact method by nitrogen substitution using seawater gas stripping technology used in the industry is advantageous. An object of the present invention is to provide a gas stripping apparatus that is inexpensive and has high performance by reducing the processing efficiency associated with a decrease in the amount of replacement gas in the multistage contact method of gas replacement, and making the apparatus compact while improving it.

Deoxygenation device that reduces and removes dissolved oxygen in water by removing nitrogen dissolved in water by replacing nitrogen dissolved in water in a nanobubble state when removing dissolved oxygen in water or seawater A plurality of holes are arranged in a plate having a nitrogen gas injection part for injecting nitrogen gas into the water to be treated and a plane through which the water to be treated into which nitrogen gas has been injected is passed, and the arrangement of the holes The upper and lower grooves of the plate are installed in the direction so that the upper and lower grooves intersect each other inside the hole, and the plates are stacked vertically so that the plates with the holes do not interfere with each other, and the units are stacked vertically. The dissolved oxygen removing apparatus is characterized in that the multi-layered laminate is made, and the water to be treated is passed through the laminate to be refined into a nanobubble state .

The plate has a thickness of 3 to 20 mm, and is composed of several 10 to 1000 holes and grooves that are aligned in the plate. The hole / groove area ratio is 10 to 100, and the hole diameter is 2 to 2. a 50 mm, the shape of the hole is a circular or polygonal, and efficiently seawater or water and nitrogen gas at a venturi effect due to the groove jet for supply of nitrogen gas and sea water or water, into the interior of the bore On the other hand, the plate upper surface groove and the plate lower surface groove can cross each other inside the hole.

In order to efficiently refine seawater or water into a nanobubble state by a venturi effect by a groove jet for supplying nitrogen gas and seawater or water , the plate is 3 to 20 mm in thickness, and several tens to 1000 in the plate The hole area / groove area ratio is 10 to 100 times, the hole diameter is 2 to 50 mm, and the hole shape is circular, or It is a polygonal shape and allows the plate upper surface groove and the plate lower surface groove to cross and pass inside the hole, and the width of the groove on the upper and lower surfaces of the plate is 0.5-5 mm, depth The angle of the hole arrangement is in the range of 1 to 179 ° by 0.5 to 10 mm.

Nitrogen gas introduction is 1m of water flow in seawater or fresh water ³ 0.005 to 1 Nm per ³ Nitrogen gas is injected into the plate at a flow rate of 0.3 to 5 m / sec, and the mixture is mixed into the mixed solution into the nanobubbles at a flow rate of 50 to 1000 L / sec. In order to achieve this, a wall body which has a cavity for efficiently generating cavitation through a hole in a plate disposed inside the mixing container and efficiently collides the fluid in a turbulent state is provided. Have.

The plate unit stored in the mixing container is made of a highly corrosive resin or metal alloy, and is used as a laminate of 2 to 100 units of plates having grooves and holes and a partition plate. .

A nitrogen substitution type deoxygenation method according to the present invention is a deoxygenation method for reducing dissolved oxygen in water by substituting dissolved oxygen in water with nitrogen, comprising a nitrogen gas injection step and a water flow step. How to do it. Moreover, it is also possible to perform a flow rate adjustment process etc. as needed. Hereinafter, each step will be described in detail.

(1) Nitrogen gas injection process The nitrogen gas injection process is a process of injecting nitrogen gas into the water to be treated. The nitrogen gas injection method performed in the nitrogen gas injection step is not particularly limited, and any method usually used in the nitrogen substitution deoxygenation technical field can be freely selected and used.
For example, a method of injecting nitrogen gas by press-fitting into the circulation line of water to be treated, a method of inhaling using an ejector, etc., and a method of injecting nitrogen gas such as efficient injection by negative pressure on the suction side of the pump And so on.

The amount of nitrogen gas injected in the nitrogen gas injection step can be freely set according to the dissolved oxygen concentration and purpose of the water to be treated. In the present invention, in order to reduce more the dissolved oxygen in the treated water, it is preferred to inject nitrogen gas through water 1 m ³ per 0.005Nm ³ ~1Nm ^3.

(2) Water flow process The water flow process is a process in which water to be treated after passing through the nitrogen gas injection process is pressurized with a pressure pump and passed through the plate. The water to be treated into which nitrogen gas has been injected in the nitrogen gas injecting step is converted into nano-scaled nitrogen in this water passing step, and replacement of dissolved oxygen with nitrogen in the water to be processed is performed.

The flow rate of the water to be treated in the water flow process is not particularly limited, and can be freely set as long as the object of the present invention is not impaired. In the present invention, the water flow is particularly preferably adjusted to 0.3 to 8 m / s, and more preferably 0.5 to 5 m / s. By setting it to 0.3 m / s or more, substitution of dissolved oxygen and nitrogen becomes efficient. Moreover, a pressure loss can be suppressed by setting it as 5 m / s or less.

The flow rate of the water to be treated can be adjusted in a flow rate adjusting step described later, but can also be adjusted by selecting the diameter of the pipe according to the amount of water to be treated.

(3) Flow rate adjustment process The flow rate adjustment process is a process of adjusting the flow rate in the water flow process. In this flow rate adjusting step, it is possible to adjust the pressure together with the flow rate adjustment. This flow rate adjustment step is not essential in the nitrogen substitution-type deoxygenation method according to the present invention, but in order to more efficiently replace dissolved oxygen and nitrogen, the flow rate adjustment step is performed to obtain a predetermined flow rate and It is preferable to adjust the pressure.

In the nitrogen substitution type deoxygenation method according to the present invention, the order in which the flow rate adjustment step is performed is not particularly limited. If the flow rate in the water flow step can be adjusted, the order in which the other steps of the nitrogen substitution type deoxygenation method can be freely performed. Can be done. In the present invention, it is particularly preferable to carry out after the nitrogen gas injection step. This is because the dissolved oxygen in the treated water can be further reduced by performing the flow rate adjusting step after performing the nitrogen gas injection step. For example, a method of performing a flow rate adjustment step immediately after performing the nitrogen gas injection step, a method of performing a flow rate adjustment step after performing the water flow step, a method of simultaneously performing the water flow step and the flow rate adjustment step, etc. It is also possible to use this method.

In the flow rate adjustment step, the flow velocity and pressure to be adjusted can be appropriately determined according to the purpose. In the present invention, the flow rate is preferably adjusted to 0.3 to 5 m / s, more preferably 0.5 to 5 m / s with respect to the plate groove. The pressure is preferably adjusted so that the pressure in the immediate vicinity of the plate entrance is 0.05 to 0.6 MPa.

According to the present invention, it is possible to obtain efficient and stable deoxygenated water by using the groove portion of the plate having holes, despite the extremely space-saving device. Technological development related to a nitrogen substitution type deoxygenation apparatus is underway, but the dissolved oxygen concentration in oxygen contained in seawater or other water could be reduced depending on the problem of the apparatus upsizing and the configuration of the apparatus.

When considering a deoxygenation method, if it is close to clean water quality, it is advantageous to use nitrogen gas in consideration of treatment efficiency and operation at a partial load. However, the water quality used in general industries can be used without removing various impurities contained in seawater or water, and can also be used in hot water.

  Schematic diagram of dissolved oxygen removal device   Shape of plate in generation of nanobubbles used in dissolved oxygen removal device A: Top view B: Bottom view C: Front view D: Plan view   Plate hole arrangement used in dissolved oxygen removal equipment A: Arrangement and angle view B: Cross section of plate hole   Detailed view of holes and grooves in plates used in dissolved oxygen removal equipment   Plate hole fluid situation diagram used for dissolved oxygen removal equipment A: Plan view B: Hole fluid situation sectional view   Plate unit diagram used for dissolved oxygen removal equipment A: Unit diagram B: Unit stack diagram   Stacking unit square shape used for dissolved oxygen removal device A: Front view B: Schematic   Laminated unit circular storage diagram used for dissolved oxygen removal device A: Front view B: Schematic diagram   Implementation apparatus diagram for dissolved oxygen removal system

The nitrogen substitution type deoxygenation method according to the present invention is a deoxygenation method for reducing dissolved oxygen in water by substituting nitrogen for dissolved oxygen in water, and includes a nitrogen gas injection step, a water flow step, and a flow rate. It is also possible to perform an adjustment process. A concrete example is shown below.

Hereinafter, the present invention will be described in more detail based on examples, and the effects of the present invention were verified. In addition, the Example demonstrated below shows an example of the typical Example of this invention, and, thereby, the range of this invention is not interpreted narrowly.

As shown in FIG. 2, the diameter of the hole of the plate in the dissolved oxygen removing device is 6 mm, and the upper surface groove and the lower surface groove of the plate intersect inside the hole as shown in FIGS. 5A and 5B. I was able to pass.

The plate was composed of holes and grooves arranged in a coordinated manner. The width of the upper and lower surface groove portions was 1.0 mm, the depth was 2 mm, and the angle of the hole arrangement was in the range of 60 degrees.

[FIG. 6] As shown in B, the plate accommodated in the mixing container has a circular shape, a diameter of 100 mm, a material made of resin, and a unit of a plate having grooves and holes and a partition plate Nine sheets were used continuously.

The nitrogen gas introduction is 1m in fresh water flow rate. ³ Per 0.3Nm ³ Water was passed at a flow rate of 2.7 m / sec in the plate into which nitrogen gas was injected.

As shown in FIG. 9, fresh water to be treated and nitrogen gas taken in from the suction pump suction side are mixed from the suction side, and the gas-liquid mixture is pumped by the pressurization pump to the mixer storage inlet side. And an apparatus for efficiently dissolving nitrogen gas at a flow rate of 120 L / min.

The hole diameter in the shape of the plate used in the generation of nanobubbles used in the dissolved oxygen removal device is 4 mm, the number of holes is 5 rows, and there are grooves above and below the holes in the hole array direction. The plate is processed with a groove width of 0.8 mm and 1 mm and a groove depth of 2 mm. Solid plate plates of the same dimensions as this plate are stacked one on top of the other, making them 1 unit, 9 units in use, and further providing a gap, and then placing them in a sealed casing with only an inlet and an outlet. A device for removing dissolved oxygen was provided. The pump to be used is a 0.4Kw-100V submersible pump. Nitrogen gas is injected and mixed from the submersible pump suction side, and the gas capacity is 2.5 L / min (flow rate of 1 m in fresh water) through a flow meter. ³ Per 0.3Nm ³ Nitrogen gas) was added. A tank capacity of 100 L was used. As shown in Table 1, the oxygen removal amount [DO value] in seawater was shown. A considerable amount of deoxygenation was shown.

In the same manner as in Example 1, the circular diameter of the hole in the shape of the plate used in the generation of nanobubbles used in the dissolved oxygen removing apparatus is 5 mm, the number of holes is five, and the number of holes in the hole arrangement direction is A plate having grooves at the top and bottom, and having a groove width of 0.8 mm and 1 mm and a groove depth of 2 mm was used. Solid plates with the same dimensions as this plate are stacked one on top of the other, and 9 units are stacked, and after a gap is provided, they are stored in a sealed casing with only an inlet and an outlet. used. The pump used was a submersible pump of 0.4 Kw-100V, nitrogen gas was injected and mixed from the submersible pump suction side, and the gas capacity was set to 2.5 L / min via a flow meter. A tank capacity of 100 L was used. As shown in Table 2, the oxygen removal amount [DO value] in seawater was shown. A considerable amount of deoxygenation was shown.

In the same operation as in Example 1, the hole diameter is 6 mm, the number of holes is 5 rows, the groove width is 0.8 mm and 1 mm, and the groove depth is 2 mm. Using the processed plates, the solid plate is stacked one on top of the other, making it a single unit, stacking 9 units, further providing a gap, and then placing them in a sealed casing with only inlet and outlet I used something. The pump used a submersible pump of 0.4 Kw-100V, and nitrogen gas was injected and mixed from the suction side of the submersible pump, and the gas capacity was set to 2.5 L / min via a flow meter. A tank capacity of 100 L was used. As shown in Table 3, the oxygen removal amount [DO value] in seawater was shown. A considerable amount of deoxygenation was shown.

In the same operation as in Example 1, the circular diameter of the holes was changed to 6 mm, the number of holes arranged in five rows, the groove width of the groove portion was 1.0 mm, and the groove depth was processed to 2 mm. Plates were used to stack solid plate plates up and down, making them 1 unit, 9 units, further providing a gap, and then putting them in a sealed casing with only inlet and outlet . The pump used a submersible pump of 0.4 Kw-100V, and nitrogen gas was injected and mixed from the suction side of the submersible pump, and the gas capacity was set to 2.5 L / min via a flow meter. A tank capacity of 100 L was used. The groove angle was 60 degrees. As shown in Table 4, the oxygen removal amount [DO value] in seawater was shown. A considerable amount of deoxygenation was shown.

As shown in Table 5, it was found that the transition of the dissolved oxygen amount dramatically improved the deoxygenation effect when a 6 mm plate was used.

1. 1. Dissolved oxygen removing device Plate 3. 3. Mixer 4. Pressure pump Nitrogen gas 6. Seawater or fresh water 7. Plate hole for mixer 8. Mixer plate top groove 9. 9. Mixer plate bottom surface groove 10. Fluid flow in the top groove of the mixer plate 11. Fluid flow in the bottom groove of the mixer plate Groove shape width 13. Groove shape depth 14. Hole array angle 15. Plate unit lamination 16. Installation in plate unit casing 17. Fluid flow 18. Casing 19. Mixture inlet 20. Gas injection part 21. Implementation test apparatus 22. Mixer gap 23. Connecting gap 24. Valve 25. Cavity 26. Mixture outlet 27. Flat plate for plate 28. Groove width 29. Groove height

Claims (6)

Deoxygenation device that reduces and removes dissolved oxygen in water by removing nitrogen dissolved in water by replacing nitrogen dissolved in water in a nanobubble state when removing dissolved oxygen in water or seawater A plurality of holes are arranged in a plate having a nitrogen gas injection part for injecting nitrogen gas into the water to be treated and a plane through which the water to be treated into which nitrogen gas has been injected is passed, and the arrangement of the holes A dissolved oxygen removing apparatus comprising: a laminate of a plurality of plates each having a plate upper surface groove and a plate lower surface groove in a direction and having upper and lower grooves intersecting at a hole portion. The plate has a thickness of 3 to 20 mm, and is composed of several 10 to 1000 holes and grooves that are aligned in the plate. The hole / groove area ratio is 10 to 100, and the hole diameter is 2 to 2. 50 mm, and the shape of the hole is circular, triangular, quadrangular, polygonal, cylindrical, conical, two-stage cylindrical, cylindrical conical, nitrogen gas and seawater or water The upper surface groove and the lower surface groove of the plate cross and pass through the hole so that the seawater or water can be mixed efficiently by the venturi effect by the groove jet for supplying The dissolved oxygen removing apparatus according to claim 1, wherein the apparatus is made uniform and refined. The plate has a thickness of 3 to 20 mm, and is composed of several 10 to 1000 holes and grooves that are aligned in the plate. The hole / groove area ratio is 10 to 100, and the hole diameter is 2 to 2. 50 mm, and the shape of the hole is circular, triangular, quadrangular, polygonal, cylindrical, conical, two-stage cylindrical, cylindrical conical, nitrogen gas and seawater or water The upper surface groove and the lower surface groove of the plate cross and pass through the hole so that the seawater or water can be mixed efficiently by the venturi effect by the groove jet for supplying The width of the groove on the upper and lower surfaces of the plate is 0.5 mm to 5 mm, the depth is 0.5 mm to 10 mm, and the hole arrangement angle is 1 to 179 degrees. Claims that are within the scope Dissolved oxygen reducing apparatus according to 1. The plate accommodated in the mixing vessel is a square, rectangle, circle, or polygon with a size of 30 to 1000 mm, and is made of a highly corrosive resin or metal alloy, 2 to 100 plates. The dissolved oxygen removing apparatus according to claim 1, wherein the dissolved oxygen removing apparatus is used in cooperation with each other. The introduction of nitrogen gas means that the flow rate in the plate for injecting nitrogen gas at a flow rate of 0.005 to 1 Nm ³ or more per 1 m ³ of seawater or fresh water is 0.3 to ⁵ m / s. The dissolved oxygen removing apparatus according to any one of claims 1 to 4, characterized in that: Water to be treated and nitrogen gas taken from the suction side of the pressurization pump is pumped by the pressurization pump to make fine particles at a flow rate of 50 to 1000 L / min. For this purpose, it has a wall body that has a cavity for efficiently generating cavitation through a hole in the plate disposed inside the mixing container and that collides the fluid in a turbulent state. The dissolved oxygen removing apparatus according to any one of claims 1 to 5, characterized in that:

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