JP2013013847A - Gas-liquid contact process and water-deoxidization process utilizing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve such a problem that the nitrogen substitution-multistage contact process is considered to be practical for general industrial use but the nitrogen consumption required in this process is not greatly reduced, even when the contact is made in three or more stages and the process has limitations on nitrogen consumption.SOLUTION: The gas-liquid contact process controls the nitrogen consumption close to the theoretical efficiency level in a multistage contact even in three or more stages, because the oversaturation of dissolved gas is completely avoided in each of the stages.

Description

  The present invention relates to a gas-liquid contact method using a stripping technique for removing dissolved oxygen in water by replacing it with an inert gas such as nitrogen or argon, and a water deoxygenation method using the same.

[Gas stripping technology]
The gas stripping technique is a method of adjusting the gas component in the liquid by equalizing the ratio of the gas composition of the liquid phase to the gas phase.
[Deoxygenation technology]
(Steam type deaeration method)
This method has been practiced by deaeration of boiler feedwater in the past. The gas component is degassed.
(Vacuum degassing method)
In order to keep water at the boiling point, the method is carried out at a pressure lower than atmospheric pressure.
(Membrane degassing method)
Oxygen permeable membrane called oxygen permeable membrane is used, and the other side of the membrane is made low pressure, so that dissolved oxygen in water passes through the membrane and moves to the low pressure side to perform deoxygenation Is the method.

(Nitrogen replacement method)
Using a contactor called a reactor or a sprinkler called an aerator, etc., by replacing dissolved oxygen and nitrogen in the water according to Henry's law, a method of reducing dissolved oxygen in the water, one form of gas stripping technology It is.
(Nitrogen replacement-in-air contact type)
In this method, water is sprinkled from the upper part of the contact tower in which a stationary reactor, a dispersion plate, and the like are arranged, and nitrogen is blown into the tower to bring it into contact with mist-like water droplets.
(Nitrogen substitution-underwater bubble contact type)
This is a method in which fine bubbles are generated when water is moved by a mechanical stirrer called an aerator and fine bubbles are dispersed in water or when compressed gas is jetted into water.
(Nitrogen substitution-single-stage contact method)
In this method, nitrogen gas and water are brought into contact with one contact device, and the nitrogen gas with reduced purity is discharged to the outside.
Although the apparatus becomes compact and the apparatus can be easily configured, a large amount of nitrogen is required to reduce the oxygen concentration in water.
(Nitrogen substitution-multistage contact method)
Nitrogen gas and water can be contacted by multiple contact devices, and the nitrogen gas in the final stage contact device can be reused as the gas for the previous contact device, thereby reducing nitrogen consumption. The device becomes complicated (for example, Patent Document 1).

[Supersaturated]
A state in which a solute is excessively contained in a solution. Say that state.
For example, a pressurized flotation method used in wastewater treatment or the like uses the principle that supersaturated air generates fine bubbles by dissolving air in high-pressure water and returning to normal pressure.
In a stable state where no energy enters and exits, eliminating supersaturation is a heat absorption reaction.
[Gas solubility]
The solubility in water varies depending on the type of gas. In general, the volume at which gas at 20 ° C. and 1 atm is dissolved in 1 ml of water is referred to as solubility. Increases to 88. In the present invention, the target gas is a gas component (hardly soluble gas) whose solubility is generally lower than that of carbon dioxide gas.
[Injector / Ejector]
An instrument that can generate negative pressure using the energy of high-speed fluid. For example, a gas injector (ejector) that uses air, steam, or the like as a driving gas, or a negative pressure generator that uses water as a driving fluid, called an aspirator, is common.
[Liquid atomizer]
It refers to a device that uses gas energy to atomize a liquid in a mist form. In the case of liquid fuel combustion, there are many examples that employ a steam spray type or air spray type burner. Water can be atomized using compressed gas such as steam or air on the same principle.

[Gas mixing means]
The gas mixing means is a device or mechanism for mixing two or more gases.
Since gas has a large momentum of molecules, it will be mixed in a confined space unless the density and temperature are extremely different.
However, when the temperature and density are different, it takes time to mix completely. Generally, the temperature in the pipe is increased to a turbulent speed, the orifice is squeezed, and a spiral blade called a static mixer is used. There are methods such as passing through a pipe line having mixing or mixing with a stirrer having a power blade.
Gas mixing is also possible by passing through a device that performs compression and expansion, such as a blower, a compressor, and a vacuum pump.
[Gas injection means into water]
The means for spraying gas into water generally has (i) a metal plate having pores, a sintered body in which fine particles are bonded, a foam having a continuous structure of bubbles, and fine holes. A submerged bubble injection method that injects gas into water through an organic film, etc. (ii) Injects gas from a nozzle-like injection tube, refines the bubbles in water by the kinetic energy of the injection, and further the surrounding water (Iii) An aerator that diffuses bubbles in the water by rotating the rotating blades etc. in water and introducing gas from the central part that has become negative pressure due to centrifugal force. There is a power combined use underwater air flow type injection method that puts gas into the suction side of a pump or the like.

[Liquid ejecting means]
The liquid ejecting means generally uses (i) a method in which pressure water is sprayed from a nozzle, (ii) a method in which water is sprinkled through a perforated plate, etc. (iii) a centrifugal force such as a rotating disk driven by power. (Iv) A spray type liquid injection method such as a method using a two-fluid nozzle using the gas energy described above, and (v) a method of splashing water droplets by colliding with an obstacle using flowing energy. (Vi) There is a flow-down type liquid jet method that uses the wettability of the solid surface to flow down the solid surface and expand the contact area and contact time.
[Boiler water preheating]
In recent years, boilers have been improved in efficiency, and most of them are provided with a function for increasing efficiency by exchanging heat of exhaust gas called economizer with water supply.
In the economizer, the lower the water supply temperature, the higher the heat exchange efficiency and the higher the boiler efficiency. However, when the water temperature is too low, the moisture in the exhaust gas is condensed.
Condensation itself is a recovery of latent heat, which is desirable in terms of efficiency, but it may cause low-temperature corrosion due to sulfuric acid contained in the exhaust gas, and the condensed water may interfere with boiler operation. It is desirable to keep the water temperature.
Although it depends on the sulfur concentration in the fuel used and the moisture ratio in the exhaust gas, the appropriate water temperature is about 40 ° C for the low-sulfur A heavy oil, which is a typical liquid fuel, and about 30 ° C for the 13A gas fuel. It is considered.

[Inert gas]
Inert gas refers to a gas that does not exhibit oxidation, reduction, acidity, alkalinity, or the like and does not bind to other elements in a target environment, and representative gas is helium, Although it is a rare gas group element such as neon or argon, nitrogen gas can also be used as an inert gas in a general environment.
[Gas compression means]
The gas compression means generally indicates a compressor (reciprocating type, screw type, scroll type, etc.) that uses rotational power, but directly utilizes the reciprocating motion of a diaphragm, piston, etc., using the energy of the fluid. Although it is also in the low pressure region, it is possible to give a gas compression action.
[Fluid suction means]
The gas suction means generally refers to a vacuum pump (water flow type, reciprocating type, screw type, scroll type, etc.) that uses rotational power, but reciprocating a diaphragm, piston, etc. using the energy of the fluid. Directly using motion and injectors are gas suction means with excellent performance.

[Liquid transfer means]
The liquid transfer means generally indicates a pump driven by rotational power. However, a pump using a reciprocating motion such as a diaphragm using a gas energy or a piston, an injector using a suction force by a high-speed air flow, or the like is also a liquid. Has transfer capability.
[Liquid stirring means]
The liquid agitation means is a device for stirring liquids or liquids and gases that are generally driven by rotational power called a stirrer, a mixer, etc., but is mixed using a liquid flow rate called a static mixer. There is also a method of generating a water flow or a turbulent flow by blowing a high-pressure gas or a high-pressure liquid into the liquid.
[Temperature detection means]
The temperature detection means consists of a temperature sensor such as a platinum temperature measuring pair, thermocouple, thermistor, etc. and its amplifier, which converts the temperature signal into an electrical signal or turns on when a preset temperature is reached. In addition to electrical detection means that outputs a signal that turns off, mechanical detection means that outputs an ON / OFF signal when a preset temperature is reached by a mechanical operation utilizing the temperature expansion of bimetal or fluid. Etc.

[Vapor detection means]
As the steam detection means, there is generally a means for detecting by a temperature detection means in addition to a means for detecting a constant pressure by a contact signal of a pressure switch or an analog signal from a pressure sensor.
[Flow detection means]
As the flow rate detection means, in addition to what is called a flow meter that detects the differential pressure, flow rate, volume, mass, etc. of the fluid and converts it into an electrical signal, it detects the decrease or increase of a fixed capacity tank, There are methods that estimate the flow rate from the specified flow rate based on the operating time.
[Fluid control means]
Fluid control means include solenoid valves that control fluid by opening and closing of valves, motor valves, air valves and other ON / OFF control valves, and control valves that linearly control valve opening using electrical air instrumentation signals There is a method.

[Fluid switching means]
The fluid switching means is realized by switching the outlet of a valve having one inlet and two outlets, usually called a three-way valve. However, the same function can be realized by preparing two valves, closing one and opening one.
They can be switched remotely by air or electrically, or manually.
In addition, there is a method in which one side of the outlet is a valve that requires cracking pressure, such as a safety valve, and switching is performed only by opening and closing one valve.
[Gas mixing means]
As the gas mixing means, there is generally used a method in which two or more kinds of gases are passed through an orifice part or mixed by a mixer such as a static mixer.
In addition, when an injector is used, high pressure gas and low pressure gas can be mixed at a medium pressure.

[Vapor supply means]
The steam supply means is to supply steam manually or automatically after receiving the original steam in combination with steam trap, pressure reducing valve, safety valve, strainer, manual valve, solenoid valve, motor valve, control valve, etc. However, the device configuration may differ depending on the original vapor pressure, the vapor pressure on the use side, or the like.
[Water vapor condensing means]
The water vapor condensing means is a general term for means for condensing water vapor in contact with water, and is similar to an injector called an aspirator. The method of using warm water is common.
In addition, steam condensation is performed if steam is condensed in water via an orifice, steam is absorbed by flowing water, water is sprayed into steam, or the contact surface between water and steam is increased. be able to.
[Pump suction capacity]
The suction capacity of the pump refers to the ability of the liquid that can be pumped up from a liquid surface with a difference in height.
If the water vapor pressure or the vapor pressure of the target liquid is ignored, the value obtained by dividing the atmospheric pressure by the density of the liquid is the maximum suction capacity of the target liquid.
100000 (Pa) ÷ 1000 (kg / m ³ ) ÷ 9.8 (m / s ² ) = 10.2 (m)
Since this is a value ignoring the vapor pressure, a value obtained by dividing the value obtained by subtracting the vapor pressure at the liquid temperature to be absorbed by the density is a theoretical value of the suction capacity.
In practice, due to cavitation generated inside the pump, a value higher than the above-mentioned ability by +50 KPa is a practical suction ability.

JP 2009-106943 A

[Classification of degassing methods]
(Steam type deaeration method)
The steam degassing method is an old and highly reliable system, but in the case of discontinuous operation, it is currently large in size due to poor thermal efficiency and special space required for installation of degassing tanks, etc. It is only used for general-purpose boilers and is rarely used for general-purpose boilers.
(Vacuum degassing method)
The vacuum degassing method can also degas the feed water near room temperature. However, in order to increase the degassing efficiency, the vacuum pump needs to suck in a large amount of water vapor and requires a large amount of power for the vacuum pump. To do.
(Membrane degassing method)
Membrane deaeration is a method of removing dissolved oxygen in water by using a membrane that is easy to selectively permeate oxygen and making the opposite side in contact with water vacuum, and theoretically the vacuum pump is submerged in water. Since it only discharges dissolved oxygen, it is small and requires less power.
However, since the gas permeable membrane is a method that allows only gas to pass through fine pores at the molecular level, it is not susceptible to contamination and temperature changes in principle, and it can be applied to water supply when recovering steam drainage. There are problems such as not.
(Nitrogen replacement-in-air contact type)
In the air-droplet contact type, the momentum of gas molecules is fast in the air and slow in water, so it has the feature of increasing the replacement efficiency by making fine water droplets. On the other hand, a large contact space is required, so that the apparatus may be enlarged.
In addition, since the amount of nitrogen used relative to the amount of water is small, it is difficult to control the purity of nitrogen in a contact device having a large volume space. Especially when the amount of water is reduced or the device is stopped, the nitrogen purity in the contact device And the removal efficiency of dissolved oxygen is not sufficient.

(Nitrogen substitution-underwater bubble contact type)
The underwater bubble contact type is a method of dispersing fine bubbles in water, but the underwater bubble type is that the gas in the fine bubbles with a large momentum of the gas is immediately saturated with the dissolved gas around the bubbles, which is farther away. It takes time to saturate with dissolved gas in water.
(Nitrogen substitution-single-stage contact method)
In the single-stage contact method, the apparatus is compact and easy to control, but in order to reduce the dissolved oxygen in 1 m ³ water containing 10 ppm of dissolved oxygen to 0.5 ppm or less, the contact efficiency is set to 100%. Even assuming that a nitrogen purity of 99.9% is used, as much as 700 L of nitrogen is required.
(Nitrogen substitution-multistage contact method)
As a method for solving the above problem, in the case of a multistage system in which the last stage replacement gas is used in the tower in the preceding stage, theoretically the same conditions as described above, 140L for the two-stage system, 80L for the 3-stage system, 4L In the stage type, the amount of nitrogen can be reduced to about 60L. However, even if processing is actually performed in multiple stages of two or more stages, if the amount of replacement gas is 200 L or less, the processing efficiency will reach its peak, and even if the number of stages is increased to two or more stages, the equipment will only be complicated and the benefits will be increased. There is no stripping apparatus exceeding two stages as a practical apparatus until now.

[Problems to be solved]
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, the use of water for general industrial purposes is extremely limited due to restrictions such as deterioration of membrane performance due to various impurities contained in water and the inability to use hot water.
Therefore, in the general industrial level deoxygenation process, a multi-stage contact method by nitrogen substitution using gas stripping technology is advantageous.
It is an object of the present invention 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.

[Nitrogen substitution-Improvement of contact efficiency of multi-stage contact method]
(Purpose of improving contact efficiency)
An object of the present invention is to provide a compact deoxygenation technique that overcomes the above-described problems of the nitrogen substitution-multistage contact method, which is considered to be practical in general industrial applications, and suppresses the consumption of substitution gas.
(Problems of deoxygenation by nitrogen substitution)
When stripping with nitrogen gas for deoxygenation based on Henry's law, gas-liquid exchange based on Henry's law is usually performed at the gas-liquid contact part, and the balance between the water side and the gas side It was believed that the dissolved gas ratio on the water side was determined according to the ratio.
However, it has been found that the processing efficiency is greatly reduced when the gas amount is reduced to 200 L or less per 1 m ^{3 of} water in a test apparatus that performs gas-liquid contact according to the conventional method and has a multi-stage configuration. .
To explain the reason, the theoretical calculation of deoxygenation by nitrogen replacement according to Henry's law is performed. The solubility of air-balanced oxygen and nitrogen in water at room temperature (15 ° C) is as follows: .
Oxygen: 10.15 ppm (7.1 NL)
Nitrogen: 16.7 ppm (13.4 NL)
The theoretical nitrogen requirement for lowering dissolved oxygen to 0.5 ppm or less in a single stage treatment can be achieved by setting the oxygen concentration in the gas phase to 1%, and can be obtained by the following formula.
1 (%) = dissolved oxygen volume / (dissolved oxygen volume + dissolved nitrogen volume + required nitrogen amount) * 100
If this is an equation for determining the amount of necessary nitrogen, the amount of necessary nitrogen = (dissolved oxygen volume− (dissolved oxygen volume + dissolved nitrogen volume) / 100) * 100
= 688.9NL
However, when the high purity nitrogen gas has a sufficient abundance ratio with respect to the amount of dissolved oxygen, when the supersaturation of the nitrogen gas is eliminated, the gas replacement by the local Henry's law with the dissolved oxygen around the bubbles is performed. Done. This is temporarily called nitrogen purge.
If the dissolved oxygen after this purge is reduced to about 1 ppm (0.71 NL), the nitrogen gas is oversaturated 10 times, so that the oversaturation is easily eliminated. The oxygen concentration of the gas to be separated can be reduced to 0.3%, and the dissolved oxygen can also be reduced to about 0.17 ppm.
That is, in the conventional gas-liquid contact method, in the case of the number of processing stages of about one or two stages, the micro-Henry is more effective than the gas exchange according to the macro Henry's law that balances the entire gas phase. By using purging according to the law, consumption of nitrogen gas is reduced and apparent processing efficiency is improved.
However, it has been found that the situation is completely different when the number of processing stages is three or more.
The following shows the dissolved oxygen and process gas oxygen concentrations of each stage, with a theoretical value of 100% efficiency of the four-stage process.
Prerequisite:
Water temperature: 15.5 ° C
Dissolved oxygen: 10.04 ppm (7 NL)
Dissolved nitrogen: 16.64 ppm (13.3 NL)
Theoretical nitrogen gas amount: 60NL
First stage outlet of water Dissolved oxygen: 5.4 ppm, treatment gas oxygen 11.25%
Second stage water outlet Dissolved oxygen: 2.8 ppm Process gas oxygen 5.8%
3rd stage water outlet Dissolved oxygen: 1.3ppm Process gas oxygen 2.8%
Water 4th stage outlet Dissolved oxygen: 0.5ppm Process gas oxygen 1.1%
That is,
(I) The amount of treatment gas is 5 times or less of the dissolved nitrogen, and when it is supersaturated, it is completely absorbed and a purge effect cannot be expected.
(Ii) Considering the first-stage outlet of water, the oxygen concentration rises to 11.25%, which is only twice supersaturated, and it is impossible to send treated water exceeding the dissolved oxygen of raw water to the subsequent stage. .
The reason why there was no practical four-stage treatment facility in the conventional method is that the last-stage gas with high purity is supersaturated and flows out into the treated water, and it is difficult to supply the latter-stage treated gas to the pre-treated water. This is because the processing efficiency is rapidly deteriorated.
In other words, if it is attempted to suppress the amount of processing gas to 200 NL or less in multi-stage processing, a useful nitrogen purge effect cannot be expected when the amount used is more than that, and the oversaturation is surely eliminated at each processing stage. It was necessary to make the processing method more faithful to the macro Henry's law.
The value of 200 NL or less corresponds to about 10 times the total amount of dissolved oxygen and dissolved nitrogen, which is a general poorly soluble component of water quality, 20.3 NL. This is thought to be because the condition is difficult to be resolved.

(Conditions for oversaturation elimination)
It can be said that supersaturation is a phenomenon that always occurs when rapid gas-liquid contact is attempted.
The situation in which gas is absorbed by water is a reaction in which water receives heat, and energy equal to the value at which the kinetic energy of the gas becomes almost zero in water is absorbed by water.
This is almost equal to the heat of condensation of the target gas.
For this reason, when there is almost no heat in and out of water, it is considered that the thermal energy absorbed by the gas becomes the gas release energy in the liquid, and the concentration balance between the gas phase and the water phase is balanced. In this case, bubbles are not generated for gas-liquid balance, and gas exchange is performed directly on the gas-liquid contact surface.
However, if a larger amount of energy is applied to perform gas-liquid contact, the added energy is offset by the evaporation of water, and in the state where the motion of gas-liquid contact has subsided, the kinetic energy of supersaturated gas molecules is reduced. It will be stable.
That is, energy is required for the supersaturated dissolved gas to become a gas, but it is difficult to receive the energy when the temperature decreases due to evaporation of water.
Therefore, it can be seen that in order to eliminate the supersaturation, it is necessary to give kinetic energy and to give the kinetic energy necessary for the supersaturated gas to become a gas.
(Means for eliminating supersaturation)
To eliminate supersaturation, the supersaturated gas is allowed to exist in water as a bubble, and the supersaturated gas is separated into fine bubbles by a specific trigger and absorbed into the parent bubble, allowing efficient supersaturation. Can be eliminated.
For this reason, in order to make the foam as a parent first, it is necessary to contact 200 NL (10 times the total hardly soluble gas) or more of the gas, but the amount of gas supplied can be reduced by multi-stage treatment. Since it is below this, it is indispensable to repeatedly use the gas-liquid separated gas.
However, as described above, this is a risky method for reducing the dissolved oxygen concentration in treated water. If it is supplied to the subsequent treatment or process in a slightly supersaturated state, the dissolved treatment water sent to the latter is dissolved. This will increase the oxygen concentration.

(Atmospheric pressure fluctuation effect in gas-liquid contact)
The atmospheric pressure fluctuation effect means that the atmospheric pressure of the gas-liquid contact portion and the treated water tank communicating therewith is shaken by about ± 10 KPa, and the atmospheric pressure at the lowest temperature with respect to the atmospheric pressure is lowered to −10 Kpa or less in the case of room temperature water temperature. Under such gas-liquid contact conditions, the air chamber including bubbles in water is characterized by a relative humidity of approximately 100%. For this reason, during pressurization, the gas component inside the surrounding bubbles becomes supersaturated, and at the same time, water vapor saturated in the air chamber side condenses into water by compression, so that the energy of the supersaturated gas moves In the next decompression process, the volume of the bubble that becomes the parent increases and microbubbles are generated. However, since the space between the bubbles that become the parent is narrowed at that time, the bubbles are easily absorbed by the large bubbles. .
Microbubbles generated by this level of pressure change disappear at the time of the next pressurization under normal conditions, but given the heat of condensation of water vapor and the presence of large bubbles in the surroundings, a slight pressure change But supersaturation can be eliminated efficiently.

(Water vapor condensation effect in gas-liquid contact)
Further, as another solution, it has been found that the supersaturation of the dissolved gas can be prevented by the following reason by making the gas-liquid contact portion supersaturated with water vapor.
The water vapor supersaturation referred to here means supersaturation of water vapor with respect to the treated water, and can be realized by applying a water vapor pressure higher than the saturated vapor pressure balanced with the treatment gas at that temperature to the gas phase.
(I) If the water vapor is supersaturated in the gas-liquid contact portion, the steam that has come into contact with the treated water is immediately condensed and transfers thermal energy to the treated water. This heat greatly exceeds the amount of heat required for the dissolved gas to move to the gas phase, so it can give energy to the dissolved gas that is unstable in a supersaturated state, and the supersaturated gas must have energy that can be separated from the liquid. Can do.
(Ii) The treated water temperature rises due to the condensed heat and the solubility of the dissolved gas is lowered, so that the required gas amount can be suppressed.
(Iii) The gas-liquid contact surface undergoes a minute change in atmospheric pressure due to the rapid condensation of vapor, and the above-mentioned pressure fluctuation effect is applied to bubbles located at a position away from the contact surface, thereby promoting gas-liquid contact. effective.
(Iv) When a thermal imbalance occurs in the treated water, convection occurs in the treated water and gas-liquid contact is promoted.
These effects are collectively referred to as a water vapor condensation effect in gas-liquid contact.
(Water vapor condensation effect and atmospheric pressure fluctuation effect)
The above-mentioned water vapor condensation effect can be more effectively canceled by combining with the atmospheric pressure fluctuation effect.
In other words, dissolved gas that is over-dissolved in water is in a condition that tends to cause dissolution in the pressurizing process of atmospheric pressure fluctuation effect, but because kinetic energy is given by the water vapor condensation effect, fine bubbles are difficult to be absorbed. This is because the bonding of fine bubbles in the decompression step is promoted even if there is no parent bubble. This can accelerate the bubble growth in a shorter time than the time during which the fine bubbles grow without changing the atmospheric pressure.
Of course, even in a situation where the target gas is circulated and a parent bubble is present, the water vapor condensation effect and the atmospheric pressure fluctuation effect can be combined to prevent oversaturation.

(Application to gases other than nitrogen gas)
The effect of improving the gas-liquid contact efficiency in multistage processing by eliminating supersaturation by this method is also effective for gas stripping according to Henry's law.
(Summary of means for eliminating supersaturation)
The atmospheric pressure fluctuation effect is effective even when used alone in a treatment system in which the volume ratio of the treatment gas to the treated water is 20% or more. The effect can be expected by doing.
The water vapor condensing effect is effective even when used alone, but higher processing efficiency can be expected due to a synergistic effect by combining the atmospheric pressure fluctuation effect and the circulation utilization of the processing gas.

(Water vapor energy and characteristics)
The easiest way to achieve the water vapor supersaturation condition in the gas-liquid contact portion is to supply water vapor to the gas-liquid contact portion.
When the treated water is boiler feed water, increasing the feed water temperature with the generated steam can recover the energy of the steam as it is, so that it has been generally carried out by a method called feed water preheating. .
By performing preheating of the feed water, condensation on the gas side of the feed water heater, which is an economizer that recovers the heat of the exhaust gas from the boiler, can be prevented, and the dissolved oxygen concentration also decreases as the water temperature rises.
Thus, it is common to perform preheating using steam for boiler feed water.
However, this method of use does not effectively use the two effects of kinetic energy and condensation effect of water vapor.
Water vapor has a kinetic energy equivalent to that of compressed air of 0.3 kW in terms of compressor, even with a mass of 1 kg and a water pressure of 0.5 MPa.
In addition, it is a special gas that rapidly loses volume and condenses when cooled, generating a large amount of condensation heat.
(Use of steam to improve gas-liquid contact efficiency)
In the underwater contact method of an inert gas gas and dissolved oxygen, water is mixed by the kinetic energy and heat energy of the water vapor by blowing a mixed gas in which a necessary amount of inert gas is mixed into the water vapor into the water in advance. When the water vapor suddenly loses its volume, the pre-mixed inert gas is subjected to shock compression like the water hammer around the water vapor bubbles and is supersaturated in the water. There is an action to melt in.
At the same time, the heat absorbed at this time gives energy to the surrounding dissolved gas, and a condensing effect that gives energy for eliminating supersaturation can be expected.
In the air contact method, water vapor can be used as kinetic energy to inject water vapor into a flowing water stream or to atomize treated water with water vapor. In addition, water vapor increases molecular weight by increasing the temperature of the inert gas. The effect of active movement, the effect of gathering inert gas molecules in the water vapor mixture at the interface with water when the water vapor condenses, and the gas-liquid contact efficiently, the partial pressure of the removal gas contained on the gas side, The effect of dilution with water vapor and the change in atmospheric pressure due to the sudden loss of water volume causes vibrations in the contact surface of the surrounding treated water and the inert gas, and synergizes with the condensation effect described above to increase gas-liquid contact efficiency. It was found that gas-liquid contact can be completed in a very short time.

(Active use as a power source of water vapor)
Engines that use steam as a power source include fluid suction devices called injectors, liquid atomizers, steam turbine engines, steam piston engines, steam motor engines, and the like.
Although the steam injector and the liquid atomizer are described above, in other engines, mechanical motion such as rotation and reciprocation is possible as in the case of electric power.
However, in general, mechanical motion engines that use low-pressure saturated steam as a power source are mostly low-pressure steam, because the majority of the energy that low-pressure steam has is thermal energy, so the energy efficiency is extremely low. Under such circumstances, there are hardly any examples of adoption.
However, when the remaining heat energy can be used effectively, it is extremely high considering that the conversion efficiency from heat energy to electrical energy is about 50% at the maximum when generating electricity.
And the steam engine reduces the pressure by exchanging heat with the low-temperature water and condensing the exhaust side, and the volume of the gas that is the working medium increases, so more mechanical energy is released than it is released into the atmospheric air It becomes possible to take out.

The gas-liquid contact method according to claim 1 of the present invention is the gas-liquid contact method in which the target gas and the treated water are brought into contact with each other at the gas-liquid contact portion of the gas-liquid contact device. When the total amount of the hardly soluble gas contained in the treated water is 10 times or less, the following treatments (i) to (iii):
(I) treatment to make the gas phase of the gas-liquid contact portion supersaturated with water vapor,
(Ii) A process in which the separation gas is recycled and the volume mixing ratio of the gas to the treated water is 20%
(Iii) A depressurization step in which the gas phase pressure of the gas-liquid contact portion and the storage tank communicating therewith is lower than the pressure obtained by adding 95 KPa to the water vapor pressure at the average water temperature of the treated water, and preferably at least 10 KPa than the depressurization step pressure A process of performing one cycle or more while the treated water is present in the gas-liquid contact portion and the storage tank of each unit, with a pressurization step higher than 20 KPa as one cycle,
Among them, the process (i) is performed alone or in combination with the process (ii) or (iii), the process (ii) is performed in combination with the process (iii), or All the processes (i) to (iii) are performed.

  According to the present invention, since the supersaturated state of the target gas can be eliminated as described above, the processing efficiency can be improved even when the amount of the target gas is reduced by the multistage processing. In addition, the water vapor condensation effect can be used by the process (i), the gas circulation can be used by the process (ii), and the pressure fluctuation effect can be used by the process (iii).

  The gas-liquid contact method according to claim 2 of the present invention is the gas-liquid contact method according to claim 1, wherein the gas-liquid contact device is configured such that when the treatment (iii) is performed, the pressure on the primary side is secondary. When the pressure becomes higher than the pressure on the side or reaches a preset pressure, the processing gas is discharged out of the system, and at a pressure lower than that, there is provided a backflow prevention means for preventing discharge or backflow of the processing gas or a pressure adjusting backflow prevention means. An airtight gas-liquid contact portion having an exhaust means, and a raw water control means at the raw water inlet of the gas-liquid contact portion, or a raw water supply means in which the pressure of the water supply source is lower than the lower limit pressure, and the treated water The outlet portion is provided with feed water transfer means having a suction capacity of 1 m or more, and the raw water flow rate is controlled by the raw water control means or the raw water supply means so that the flow rate is higher than the maximum flow rate of the feed water transfer means and less than the minimum flow rate. Control with , By changing the volume ratio of gas phase and the aqueous phase in the gas-liquid contact portion, and wherein the generating the air pressure change.

  In the present invention, it is possible to realize a decompression step and a pressurization step necessary for carrying out the treatment (iii) without using an expensive vacuum pump or compressor which is difficult to handle (utilization of atmospheric pressure fluctuation effect).

  The gas-liquid contact method according to claim 3 of the present invention is the gas-liquid contact method according to claim 1 or 2, wherein the gas-liquid contact portion and the treated water supply for supplying the treated water to the gas-liquid contact portion. Means, target gas supply means for supplying the target gas to the gas-liquid contact portion, treated water intake means for flowing the treated water out of the gas-liquid contact portion, and the target gas from the gas-liquid contact portion The gas-liquid contact means composed of the target gas discharge means for discharging the waste water is made one component, the treated water lines are connected in series in a plurality of stages, and the high-purity target gas is fed to the last component of the treated water. In the multi-stage gas-liquid contact process for reducing the consumption of the target gas by supplying the target gas discharged there to the component gas of the previous stage, the dissolved gas contained in the raw water of the treated water is the raw water It almost matches the saturation state of temperature and When the average temperature is relatively stable, there are four stages when the average temperature is 55 ° C. or less, and three stages when the average temperature is more than 55 ° C. and 80 ° C. or less. If the temperature is more than 80 ° C. and less than 90 ° C., the number of processing steps is adjusted based on the processing step number criterion that multi-stage processing is not selected when the average temperature is 90 ° C. or higher, and the processing When the change in the average temperature of the raw water of the water is large, the equipment should have the number of treatment stages based on the treatment stage number criterion from the lowest temperature, and the bypass means for bypassing the treatment water flow path of each treatment stage, and for the gas-liquid contact When the temperature of the treated water detected by the temperature detecting means has reached a preset water temperature, comprising at least one of power source shut-off means and temperature detecting means for detecting the temperature of the treated water The bypass means and the motion. Controlling at least one of the source interrupting means, and adjusting the number of processing stages.

According to the present invention, the gas solubility decreases as the temperature of the treated water decreases, so that the amount of target gas used also decreases. Therefore, even if the number of processing stages is increased, the effect of reducing the amount of target gas used is small, and at the same time When the water temperature is high, the number of processing stages increases, so that the heat radiation area increases and the loss of heat energy increases.
Therefore, when the water temperature is stable, the number of processing stages with the best performance can be determined by judging from the running cost and the initial cost according to the average temperature.
However, if the average water temperature changes due to seasonal fluctuations, etc., the equipment should have the number of treatment stages determined based on the minimum water temperature, and the number of treatment stages can be changed dynamically according to the water temperature, resulting in wasted power and heat dissipation. Since the loss can be reduced, the system is highly economical.

  The gas-liquid contact method according to claim 4 of the present invention is the gas-liquid contact method according to claims 1 to 3, wherein the gas-liquid contact device supplies the water vapor when the processing (i) is performed. A water vapor supply means; and a target gas supply means for supplying at least one of a target gas supplied from the outside or a contacted target gas separated from gas and liquid, and further comprising the water vapor supply means and the target gas Is it provided with steam target gas mixing means for preliminarily mixing steam and target gas from the supply means, and mixed steam condensing means for absorbing the mixed steam from the steam target gas mixing means into the treated water in the gas-liquid contact portion? In the case where the treated water and the target gas are mixed in advance in the gas-liquid contact section, the steam from the steam supply means is absorbed in the treated water and the target gas in the mixed state. A gas condensing means is provided, or both the steam condensing means are provided, and the mixed steam or the water vapor is condensed in the treated water in the gas-liquid contact portion.

  According to the present invention, when water vapor condenses, in addition to the water vapor condensing effect, a fluid stirring effect, a gas partial pressure lowering effect, a gas molecule entrainment effect, and the like act in combination, and extremely high contact efficiency can be obtained. In addition, when the purpose is deoxygenation, the consumption of the target gas can be suppressed by the effect of increasing the water temperature, so that a compact and economical gas-liquid contact method can be realized.

The gas-liquid contact method according to claim 5 of the present invention is the gas-liquid contact method according to claim 1, wherein when performing all of the treatments (i) to (iii), the gas-liquid contact device is The liquid transfer means for supplying treated water into the gas-liquid contact section includes vapor-driven liquid transfer means using steam as drive energy, or the target gas transfer means in the gas-liquid contact section as steam drive energy Or a steam-driven stirring means using steam as driving energy as a stirring means for the treated water and the target gas in the gas-liquid contact portion, and further, the steam-driven liquid transfer means, Steam condensing means for absorbing treated water with steam having reduced kinetic energy from at least one of the steam-driven gas transfer means and the steam-driven stirring means. The following methods (i) to (iii):
(I) A method of previously mixing a target gas with water vapor for driving,
(Ii) a method of mixing the target gas before flowing into the vapor condensing means;
(Iii) A method in which treated water for absorbing water vapor is mixed with the target gas in advance.
The water vapor supersaturated state is caused to exist in the gas-liquid contact portion by any one of the methods.

According to the present invention, the gas-liquid contact efficiency can be increased by the vapor condensation effect of water vapor with reduced kinetic energy after using the kinetic energy possessed by the steam to perform gas circulation utilization, and the water temperature is further increased. As a result, when the purpose is deoxygenation, the consumption of the target gas can be suppressed, so that a gas-liquid contact method with extremely excellent energy efficiency can be realized.
In addition, by using the kinetic energy of steam, processed gas in a low pressure state can be supplied to a high state position, so the combined use with the atmospheric pressure fluctuation effect can be realized more reliably for gas circulation use. can do.

  The gas-liquid contact method according to claim 6 of the present invention is the gas-liquid contact method according to claim 5, wherein the gas-liquid contact device is capable of detecting temperature in a part of the flow path of the treated water. And at least one detection means of flow rate detection means capable of detecting the flow rate of the treated water, and further, based on the temperature or flow rate of the treated water detected by the detection means, the water vapor to the water vapor drive means A driving water vapor control means for controlling the supply of water, or a condensing water vapor control means for controlling the supply of exercised water vapor to the vapor condensation means based on the temperature or flow rate of the treated water detected by the detection means. Provided, when the temperature of the treated water is lower than a predetermined temperature set in advance, when the flow rate of the treated water is higher than a predetermined flow rate, or when both conditions are satisfied, to the steam driving means The supply of steam, or and performing condensation of the treated water movement already steam.

  According to the present invention, when the water temperature is originally high, or when the flow rate of the treated water is small and the gas-liquid contact treatment by the steam power is difficult, the steam power is stopped, and the supersaturation is eliminated by the circulation utilization of the processing gas and the pressure fluctuation effect. By changing to the means, vapor absorption into the treated water can be prevented, so that a highly safe gas-liquid contact method can be realized.

  The gas-liquid contact method according to claim 7 of the present invention is the gas-liquid contact method according to any one of claims 1 to 6, wherein the gas-liquid contact device sets a temperature in a flow path of treated water or the gas-liquid contact portion. A temperature detecting means capable of detecting; a flow rate detecting means capable of detecting the flow rate of the treated water; and further, when using water vapor, a steam detecting means for supplying steam to the processing equipment, a circulation target gas flow rate detecting means, System operation normality detecting means determined from at least one of the condensed vapor flow rate detecting means, saturated oxygen concentration calculating means for obtaining a saturated oxygen concentration from a signal from the temperature detecting means, the saturated oxygen concentration, gas-liquid A required target gas amount calculating means for calculating a required target gas amount per unit flow rate from the number of contact processing stages, target gas purity, and gas-liquid contact processing efficiency when the system operation is normal; Proportional calculation means for calculating the required amount of the target gas according to the treated water flow rate from the signal from the gas amount calculating means and the signal from the flow rate detecting means, and according to the treated water flow rate by the signal from the proportional calculation means And a target gas flow rate adjusting means for adjusting the target gas flow rate, and automatically adjusting the target gas flow rate according to the flow rate of the treated water, the temperature, the number of processing stages, the system state, and the gas purity.

  According to the present invention, since the necessary target gas amount can be obtained in accordance with the change in the water temperature, the number of processing stages, and the presence or absence of steam supply, efficient operation without excess or deficiency of the target gas is possible.

  In the gas-liquid contact method according to claim 8 of the present invention, in the gas-liquid contact method according to claim 7, when a water vapor condensation effect cannot be expected by a signal from the system operation normal detection means, The gas-liquid contact efficiency value of the required target gas amount calculation means is adjusted to a smaller value than when the system is normal according to the amount of treated water per unit time that can be dealt with only by the circulation use and atmospheric pressure fluctuation effect. To do.

  According to the present invention, in use of treated water with a small flow rate, such as water filling before the start of a boiler, treated water having a prescribed dissolved oxygen concentration can be supplied even without steam, so a deaeration device that does not use steam It is economical that there is no need to provide etc.

  The gas-liquid contact method according to claim 9 of the present invention is the gas-liquid contact method according to claim 7 or claim 8, wherein the gas-liquid contact device comprises a vertically arranged gas-liquid contact portion, and the gas-liquid contact method. In the gas-liquid contact means composed of a storage tank having a lower liquid level than the uppermost part of the liquid contact part, a gas circulation pipe that communicates the gas-liquid contact part treated water falling part and the air chamber of the storage tank. Switching means for connecting the treated water outlet of the treated water supply means and the treated water inlet to the gas-liquid contact means to the gas-liquid contact means of the latter stage or the treated water supply means outlet for supplying treated water to the treated water utilization facility Or switching the communication water supply means for supplying the treated water to the gas-liquid contact means to communicate the treated water or raw water inlet from the preceding gas-liquid contact means with the treated water outlet from the gas-liquid contact means Means according to a signal from the system operation normality detection means. When there is no steam supply, or when the temperature or flow rate of the treated water is low and the steam power is shut off, the processing in the gas-liquid contact means is performed by using the liquid transfer capability of the treated water supply means by the switching means. Water is circulated and the air pressure in each stage is changed by adjusting the switching means from the previous stage and the switching means to the subsequent stage, and the separation is completed by the siphon action formed at the falling part of the gas-liquid contact part It is characterized by circulating gas.

  According to the present invention, when there is no steam power, when the water temperature is high, when the flow rate of water is small and it is difficult to use steam power, the treated water is circulated to compensate for the decrease in contact efficiency. By performing the fluctuation effect and circulating use of the separated gas, it is possible to prevent a reduction in the processing efficiency and reduce the amount of the target gas used, which is economical.

The gas-liquid contact method according to claim 10 of the present invention is the gas-liquid contact device according to any one of claims 7 to 9, wherein the gas-liquid contact device includes a flow path communicating from the raw water inlet to the treated water outlet. A circulation passage for connecting the liquid circulation means inlet to the upstream side of the communication flow path and returning the treated water stored in the treated water tank via the gas-liquid contact portion to the downstream side of the liquid transfer means inlet; A circulation type gas-liquid contact device provided with a liquid circulation means having a transfer capacity larger than the flow rate of the maximum water supply of the gas-liquid contact device is formed in one stage, the circulation type gas-liquid contact apparatus is configured in multiple stages, and at least one of the treated water tanks According to the present invention, water level control can be simplified, and the number of processing stages can be adjusted by turning on the liquid circulation means. Simplify equipment by being able to control with only / OFF Can do.

The water deoxygenation method according to claim 11 of the present invention is the gas-liquid contact method according to any one of claims 1 to 10, wherein an inert gas is used as the target gas, The gas composition is substituted with the gas composition of the inert gas.
According to the present invention, as described above, the influence due to the supersaturation of the target gas can be eliminated, and thus a compact deoxygenation technique with high use efficiency of the replacement gas can be provided.
Further, as a secondary effect, general water contains supersaturated carbon dioxide gas called free carbonic acid. Unlike carbonate ions and bicarbonate ions, this should be 1 ppm or less in equilibrium with the carbon dioxide concentration in the atmosphere (approximately 0.04%) according to Henry's law. It is easy to maintain the supersaturation, and in groundwater etc., it is often contained at about 20 to 50 ppm.
Since the present invention is also a technique for eliminating supersaturation in the process of stripping, this supersaturated free carbonic acid also has the effect of eliminating supersaturation at the same time, and is particularly suitable for water supply for steam boilers.

The deoxygenation method according to claim 12 of the present invention is the oxygen concentration detection means according to claim 11, which measures the oxygen concentration of the exhaust gas supplied from the previous processing unit to the next processing unit or exhausted to the atmosphere. The processing gas amount calculation means (necessary target gas amount calculation means) according to claim 7 is provided with at least one stage of an expected oxygen concentration calculation circuit in the processing gas, and the oxygen concentration value of the oxygen concentration detection means An oxygen concentration comparison calculation circuit that compares the predicted oxygen concentration calculation values at the same location, and in the oxygen concentration comparison calculation circuit, either the oxygen concentration is too high or the oxygen concentration is too low Or both alarms are output.
According to the present invention, a highly reliable gas oximeter such as a zirconia type or a magnetic dumbbell type can be used without using an underwater dissolved oxygen meter that is difficult to measure when the water temperature rises. When the device is abnormal, that is, when the oxygen concentration is high, it is possible to indirectly monitor the shortage of nitrogen gas or the entry of outside air into the device, or when the oxygen concentration is low, excessive nitrogen gas or a decrease in contact efficiency. A highly reliable device can be provided.

[Proper ratio of water vapor to treated water]
(Case where preheating water supply is not useful)
When it is not desirable to raise the water temperature as in a tap water supply system or a cold water supply system, it is desirable to keep the amount of water vapor used to the minimum necessary, and 0.005 to 0.00. About 1 time the amount of steam used is an appropriate value.
(Case where preheating water supply is useful)
In the case of water supply to a steam boiler, a hot water system, etc., it is not wasteful to raise the water temperature, so that the steam energy can be used effectively even if the utilization ratio of steam is increased.
In such a case, energy can be reused even if the amount of steam used is increased by suppressing heat dissipation of the water supply line according to the present invention, so there are few energy restrictions on the amount of steam used. Become.
However, the use of a steam amount such that the water temperature of the treated water generally exceeds 100 ° C is close to the deaeration method with steam, and when the water temperature is close to the saturation temperature, the suction efficiency of the pumps deteriorates or stops. Since the heat dissipation loss at the time increases, the economic effect decreases.
Therefore, the proper amount of steam used for the treated water in the case of treated water having a water temperature of 20 ° C. is preferably 0.01 to 20% in terms of mass ratio.

[Calculation of nitrogen gas requirement]
A calculation formula for obtaining the necessary amount of nitrogen gas in performing the deoxygenation treatment which is the first object of the present invention can be obtained as follows.
(Calculation formula for obtaining dissolved oxygen)
The oxygen solubility (mol) can be determined by the following formula.
Oxygen solubility = EXP (A + B / ((temperature (° C.) + 273) / 100) + C * LN ((temperature (° C.) + 273) / 100))
A: -66.773538
B: 87.47547
C: 24.45264
The amount of dissolved oxygen (volume ppm) can be determined by the following formula.
Amount of dissolved oxygen = oxygen solubility * 1000000 * 0.21 * 32/18
The amount of dissolved oxygen (volume ppm) in consideration of the partial pressure of water vapor can be determined by the following equation.
The amount of dissolved oxygen in consideration of the partial pressure of water vapor = the amount of dissolved oxygen * (1.03-partial pressure of water vapor (bar)) / 1.033
Here, the water vapor partial pressure is obtained from the vapor table.
(Calculation method to obtain theoretical nitrogen consumption according to the number of processing stages)
In the case of a single-stage treatment, the water oxygen gas volume and water nitrogen gas contained in the treated water are determined according to the three parameters of dissolved oxygen concentration, nitrogen gas purity, and nitrogen gas amount contained in the treated water. The volume is determined, the gas oxygen gas volume and the gas nitrogen gas volume are determined from the nitrogen gas purity, and further, the total oxygen gas volume and the total nitrogen volume are determined.
The nitrogen solubility (mol) can be determined by the following formula.
Nitrogen solubility = EXP (A + B / ((temperature (° C.) + 273) / 100) + C * LN ((temperature (° C.) + 273) / 100))
A: -67.38765
B: 86.32129
C: 24.79808
Nitrogen solubility = nitrogen solubility * 1000000 * 0.79 * 28/18
Nitrogen dissolved amount considering water vapor partial pressure = nitrogen dissolved amount * (1.033−water vapor partial pressure) /1.033
The post-treatment dissolved oxygen concentration (volume ppm) can be determined by the following formula.
Dissolved oxygen concentration after treatment = initial dissolved oxygen concentration * (total oxygen / (total oxygen + total nitrogen)) / (21/100)
The nitrogen gas purity (volume%) after the treatment can be obtained by the following formula.
Nitrogen gas purity after treatment = (1−total oxygen / (total oxygen + total nitrogen)) * 100
In the case of two or more stages of treatment, the above calculation is performed for each stage of treatment, but the purity of the nitrogen gas in the previous stage becomes the purity of the nitrogen gas that has been treated in the subsequent stage, and the dissolved oxygen sent to the subsequent stage is the amount after the treatment in the previous stage. When the calculation is recursively performed so that the dissolved oxygen becomes, the exhausted nitrogen gas concentration and the treated aqueous oxygen concentration converge.
Since the dissolved oxygen concentration at the time of convergence is obtained by changing the amount of nitrogen gas by recursive calculation, the necessary amount of nitrogen gas in the case of multistage processing is calculated by changing the amount of nitrogen gas and calculating the dissolved oxygen concentration. Can be requested.
However, since this calculation method has a heavy burden on the calculation processing system for use in control, it is common to obtain and use an approximate expression from the values obtained by plotting them, or to obtain the interval between plot points by an interval proportional method or the like. Is.
For reference, graphs of theoretical nitrogen consumption at a nitrogen purity of 99.9% are shown in FIGS. 6a to 6g.

(Calculation method of actual required nitrogen amount with treatment efficiency taken into account)
Obtaining the amount of nitrogen gas necessary for the target dissolved oxygen concentration in consideration of the processing efficiency requires calculation in consideration of the processing efficiency in the recursive calculation, and it is still necessary to obtain it dynamically. Since the calculation processing system is burdensome, it is common to calculate a value that considers the contact rate according to the processing conditions and find the plotted data according to the processing pattern by approximation processing, proportional method, etc. It is.
(Importance of determining the required amount of nitrogen)
In the gas-liquid contact method using the gas stripping technique such as the deoxygenation method by nitrogen substitution, the gas component concentration contained in the raw water greatly varies depending on the water temperature, and the amount of consumption of the target gas greatly varies accordingly.
In particular, in the multistage method, the actual required amount based on the theoretical value and the performance of the apparatus is likely to change greatly depending on the water temperature. Therefore, management based on such a calculation is important for the maintenance management of the apparatus.

Explanatory drawing which shows an example of the nitrogen substitution method of the underwater spray type in a tank. Explanatory drawing which shows an example of the water spray type nitrogen substitution method in a pipe line. Explanatory drawing which shows an example of the nitrogen substitution method of the air contact type using water vapor | steam nitrogen mixed gas. Explanatory drawing which shows an example of the nitrogen substitution method of water vapor | steam separation type air contact type. Explanatory drawing which shows an example of the nitrogen replacement method of the air contact type | mold using the water vapor | steam nitrogen gas mixing spray type water nozzle. Explanatory drawing which shows an example of the nitrogen substitution method of the air contact type using a water vapor spray type water nozzle. Explanatory drawing which shows an example of the application to the counterflow type air contact type in a tank. Explanatory drawing which shows an example of the flow which implement | achieves an atmospheric | air pressure fluctuation effect using the suction capability of a treated water pump, and a water supply control valve. Explanatory drawing which shows an example of the flow which implement | achieves a pressure fluctuation effect when the pressure of a water supply source is lower than the minimum pressure required for a pressure fluctuation effect. Explanatory drawing which shows an example of an injector type water vapor mixed gas generator. Explanatory drawing which shows an example of a steam injection nozzle ((A) side view, (B) front view). Explanatory drawing which shows an example of a water vapor spray type water nozzle ((A) partial cross section side view, (B) front view). Explanatory drawing which shows an example of the flow of a multistage deoxygenation apparatus. Explanatory drawing which shows an example of the flow of the multistage deoxygenation apparatus which performs the dynamic change of the process stage number by water temperature. Explanatory drawing which shows an example of the flow of the multistage type deoxygenation apparatus using a water vapor drive engine. Explanatory drawing which shows an example of the flow of a multistage deoxygenation apparatus with a communication pipe type circulation type gas-liquid contact apparatus. Explanatory drawing which shows an example of the flow in which a communication pipe serves as a part of treated water tank in the flow of a multistage deoxygenation apparatus with a communication pipe-type circulation type gas-liquid contact apparatus. Explanatory drawing which shows an example which provides a check valve in a communicating pipe and prevents the backflow between treated water tanks in the flow of a multistage deoxygenation apparatus having a communicating pipe-type gas-liquid contact device. Explanatory drawing which shows an example of the flow of a water temperature detection type nitrogen amount adjustment type multistage deoxygenation apparatus. The graph which shows the theoretical nitrogen consumption of raw | natural water of 2% of dissolved oxygen concentration. The graph which shows the theoretical process consumption of raw | natural water of dissolved oxygen concentration 4%. The graph which shows the theoretical process consumption of raw | natural water of 6% of dissolved oxygen concentration. The graph which shows the theoretical process consumption of raw | natural water of 8% of dissolved oxygen concentration. The graph which shows the theoretical consumption of raw water with a dissolved oxygen concentration of 10%. The graph which shows the theoretical consumption of raw water with a dissolved oxygen concentration of 12%. The graph which shows the theoretical consumption of raw water with a dissolved oxygen concentration of 14%.

[First Embodiment]
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a first embodiment of the invention will be described with reference to the drawings.
FIG. 1a is an example of an underwater spray-type nitrogen displacement deoxygenation apparatus according to this embodiment.
A steam injector (24) and a buffer chamber (27) are arranged in the lower part of the treated water tank (1), and a steam pipe (21) and a nitrogen pipe (11) are connected to the steam injector (24). ing.
The buffer chamber (27) and the treated water tank (1) are partitioned by a screen (28).
The screen (28) is made of a sintered body having fine holes, a metal multi-hole plate, or the like. However, the screen (28) can withstand the heat of the steam and the steam ejected from the screen (28) loses its volume. It is necessary to have a structure that can withstand vibrations that sometimes occur.
The raw water flowing in from the raw water pipe (31) flows into the inner pipe (9) installed so as to surround the screen outlet.
Steam and nitrogen are blown into the steam injector (24) simultaneously with the inflow of raw water. The amount of nitrogen is determined according to the dissolved oxygen concentration of the raw water and the dissolved oxygen concentration required for the treated water after treatment, and the amount of steam is nitrogen. Supply about 50 times the mass (mass ratio). The vapor amount is preferably 5 to 200 times the nitrogen amount.
When the steam mixed gas is sprayed from the screen (28), heat is exchanged with the raw water flowing into the inner pipe (9), and the steam disappears in the vicinity of the outlet of the fine hole.
The flow rate of the raw water flowing into the inner pipe (9) may be a low flow rate of about 10 cm / s, and the raw water in the inner pipe is uniformly supersaturated by the stirring effect by the jetted steam, and rises in the treated water tank (1).
Fine bubbles are generated around the inside of the inner tube (9), and gas-liquid separation is performed while being combined. The generated replaced gas is discharged to the outside from the nitrogen exhaust pipe (12) via the check valve (13), and the treated water is supplied to the deoxygenated water utilization equipment via the treated water pipe (32). Is done.
The buffer chamber (27) is a space necessary for converting the kinetic energy into pressure by reducing the flow velocity of the steam ejected by the steam injector (24). It is also possible to keep the pressure.

FIG. 1 b is an example of a nitrogen substitution deoxygenation apparatus when performing gas exchange in a pipe.
A buffer chamber (27) partitioned by a screen (28) on the upstream side of the contact tube (66) and a steam inlet for supplying a steam mixed gas to the buffer chamber (27) while sucking nitrogen into the buffer chamber by the energy of steam. A zector (24) is arranged.
The treated water passes through the contact pipe via the raw water pipe (31), and the treated water flows out through the treated water pipe (32) via the gas separation chamber (29).
A nitrogen exhaust pipe (12) communicates with the upper part of the gas separation chamber via an automatic gas vent valve (25).
The treated water is brought into contact with the steam mixed gas that has passed through the screen (28) at the inlet of the contact pipe, and the gas compression action of the gas when the steam is condensed and the impact of the nitrogen gas and the treated water by the impact transmitted in the contact pipe. Liquid mixing is promoted.
When the distance from the vapor contact point increases, the fine bubbles separated from the water start to bond with each other, and the gas is separated into the upper part in the vicinity of the gas separation chamber. The separated gas passes through the automatic degassing valve (25). Exhausted outside.
In FIG. 1a and FIG. 1b, although not explicitly shown in the drawing, the nitrogen exhaust pipe (12) and the nitrogen pipe (11) are connected, and while increasing the volume of nitrogen gas blown into the water, It is also possible to circulate and use a gas so that a part of the gas is discharged out of the system.
In this case, the gas-liquid contact can be performed more efficiently due to the presence of the kinetic effect of the gas released into the water and the bubbles serving as nuclei simultaneously with the water vapor condensation effect due to the condensation of water vapor.
This is the same effect as an aerator that has a rotating blade called an aerator and has a negative pressure at the center, but the structure for generating negative pressure is simple, and the direction of water flow diffusion is unidirectional. Since it can limit, size reduction and high flow velocity are easy, and even if it comprises in multiple stages, installation cost can be suppressed.
FIG. 3a is a structural diagram of a steam injector used in the present embodiment and the like. The steam flowing in from the steam inlet (61) becomes a high-speed flow at the steam nozzle (62), the speed is reduced at the diffuser section (63), the pressure is recovered, and the steam is exhausted through the outlet section (64).
At this time, a negative pressure is generated in the suction part (65), and a gas or liquid is sucked and discharged from the outlet part together with the steam.
In gas-liquid contact using water vapor, since the kinetic energy of water vapor is large, sufficient contact efficiency can be obtained without using a contact aid such as a special contact plate or contact material. Even if a mechanism having an effect of increasing the contact efficiency is provided, it can be used without any problem.

[Second Embodiment]
Hereinafter, a second embodiment of the present invention will be described with reference to the drawings.
FIG. 2A is a flow diagram of the air contact type nitrogen substitution deoxygenation apparatus according to the present embodiment.
A contact tower (6) is disposed in the upper part of the treated water tank (1), and the lower part of the contact tower is opened below the surface of the treated water tank.
A gas mixer (26) is connected to the contact tower (6), and a steam pipe (21) and a nitrogen pipe (11) are connected to the gas mixer (26).
A raw water pipe (31) is connected to the upper part of the contact tower via a water spray plate (7).
When raw water is passed through the raw water pipe (31), the water flow dispersed by the water spray plate (7) flows down into the contact tower. At the same time, a mixed gas similar to that of the first embodiment is generated in the mixer through the steam pipe (21) and the nitrogen pipe (11), and supplied to the contact tower (6). The vapor amount is preferably 5 to 100 times (mass ratio) of the nitrogen amount.
When the flowing water stream comes into contact with the water vapor, the water vapor condenses and loses its volume, so that the mixed gas forms a high-speed flow toward the dropped water droplets.
Therefore, nitrogen gas stays at a high concentration on the surface of the water droplet, but the movement direction of the gas molecules is limited by the high-speed flow caused by the condensation of water vapor, so that it dissolves in the water droplet in a supersaturated state.
However, at the same time, dissolved gas molecules in water are given enough energy to eliminate supersaturation due to the heat of condensation of water vapor.
Water droplets in which nitrogen gas is dissolved in a supersaturated state fall to the lower part of the contact tower, the supersaturation degree of water vapor in the gas phase is lowered, and as soon as water vapor condensation weakens, bubbles are separated in the treated water tank.
The treated gas that has been gas-liquid separated is discharged from the nitrogen exhaust pipe (12).
The treated water is supplied to the deoxygenated water utilization device via the treated water pipe (32).
In this case, the use rate of water vapor is approximately 5 kg per 1 m ³ of treated water in a single stage.

FIG. 2b has a configuration substantially similar to that of FIG. 2a, except that the inflow point of nitrogen gas is the raw water pipe (31) in front of the sprinkler plate (7) at the top of the contact tower (6), and the treated water falls in the form of water droplets By injecting the steam from the steam nozzle (62) in the vicinity of the middle stage, the gas-liquid contact is promoted by the effect of the steam movement and the effect of the surrounding inert gas when the steam condenses into the treated water.
The steam nozzle (62) used in FIG. 2b is a nozzle having a fan-shaped spray pattern with slits horizontally as shown in FIG. 3b. Is efficient because of contact.
In this case, the steam usage rate is approximately 2 kg per 1 m ³ of treated water in a single stage.

FIG. 2c is an example of a method in which the steam injector (24) is used for suction of treated water and nitrogen gas, and the mist-like treated water and nitrogen gas are promoted to gas-liquid by the condensing action of water vapor. is there.
In this embodiment, both functions of a pump for transferring treated water and a compressor for transferring nitrogen gas can be performed by a single steam injector (24), and the gas-liquid contact between the treated water and nitrogen gas is also performed in the injector. In the contact tower, gas-liquid contact is promoted by the condensing action of water vapor.
In this case, the amount of water vapor used is increased, and approximately 30 kg of water vapor is required per 1 m ³ of water in a single stage, so that a water supply preheating effect can be expected.

FIG. 2d is an example in which a vapor-type liquid spray nozzle (70) that forms fine water particles by the spray section is used.
A fine mist of several μm is formed and gas-liquid contact is made with nitrogen gas.
FIG. 3c is an example of the structure of the vapor-type liquid spray nozzle (70). The steam supplied from the steam inlet part (61) becomes a high-speed flow at the inlet part of the injection hole (71), and the raw water supplied from the raw water pipe (31) is atomized on the principle of spraying, from the injection hole (71). Sprayed as a fine mist.
In the case of the spray nozzle (70), there is no fluid suction capability, and it is necessary to raise it to about 0.3 MPa by a pump. In addition, the consumption of steam is the largest, and steam at a pressure of about 0.5 MPa of about 50 kg per 1 m ³ is required in a single stage. It is also possible to previously mix nitrogen gas into the steam.
In addition, in such a configuration, when the upper part of the contact tower is set lower than the surface of the treated water tank, when only the raw water or treated water is supplied when there is no steam, the nitrogen pipe (11) becomes a negative pressure due to siphon action, The separation gas can be recirculated by communicating with the nitrogen exhaust pipe (12).

FIG. 2e is an example of a counter-flow type in a contact tower.
Nitrogen is supplied from the nitrogen pipe (11) to the upper part of the storage tank (1) and exhausted out of the system through the nitrogen exhaust pipe (12) while flowing back through the vent pipe (8).
The raw water is supplied into the tower from the raw water pipe (31), and flows down to the storage tank (1) through the watering plate (7), contrary to the nitrogen gas.
The vapor-liquid contact efficiency is increased by spraying the steam with the steam nozzle (62) in the space where the treated water flowing down and the rising nitrogen gas exist.
The characteristic of the counterflow type is that the gas utilization improvement effect similar to that of the multistage configuration can be expected because a concentration gradient between nitrogen gas and treated water can be formed in the contact tower during rated operation.
However, in the case of the conventional static reactor type (sprinkling plate), a contactor called a static reactor that circulates the flowing water and the rising gas is required to compete with each other. This makes it difficult to increase the size of the apparatus and at the same time to obtain sufficient replacement efficiency.
In this embodiment, by spraying water vapor on the flowing water stream and the rising nitrogen gas, the processing efficiency is improved by the kinetic energy and the water vapor condensation effect, so that the flow velocity can be increased and the apparatus can be designed compactly.
Also, the steam nozzle (62) can be changed to a steam ejector to eliminate the vent pipe (8). In this case, the lower processing gas is sucked and the mixed gas is blown from the steam ejector. Since the processing gas easily flows back through the pores of the plate, the contact efficiency is improved, and the processing chamber tends to have a negative pressure. Furthermore, an atmospheric pressure fluctuation effect can be provided by supplying steam intermittently.

FIG. 2 f shows a basic configuration for providing an atmospheric pressure fluctuation effect, and shows a case where the water surface level of the raw water tank (2) is higher than the uppermost part of the contact tower (6). The same effect can be expected even when a pump is added as appropriate when there is a fluctuation in the water level.
The raw water passes through the raw water pipe (3) and is blocked at the raw water control valve (45) at the high water level (9a) of the float water switch (43) and opened at the low water level (9b) of the water tank. It becomes the control which becomes.
Nitrogen gas or the pretreated gas is supplied from the nitrogen pipe (11) to the contact tower via the check valve (13).
The treated gas is exhausted to the outside air or the next-stage contact tower via a check valve (13) connected to the nitrogen exhaust pipe (12).
Since the supply amount of nitrogen gas is 20% or less of the volume ratio of the treated water in the present invention, when the treated water pump has a water amount of 2 t / h, it is at most 400 NL / h, and the raw water control valve is When it is closed and raw water is not replenished, the supply of the processing gas is insufficient, so the pressure in the air chambers of the processing tower and the processing water tank decreases.
When the water level of the treated water tank becomes low and the raw water control valve is opened, if the amount of water of 4 t / h larger than the capacity of the treated water pump is replenished, the air chamber will be compressed, and the pressure in the air chamber will be In the case of rising and exhausting to the outside air, if the pressure becomes higher than the static pressure necessary to open the check valve connected to the nitrogen exhaust pipe, the air is exhausted to the outside air.
If the check valve connected to this nitrogen exhaust pipe is changed to a pressure regulating valve that can be opened at a constant pressure, such as a safety valve, the control gas can be controlled to be discharged at a pressure higher than atmospheric pressure. Is possible.
In this way, when discharging at a pressure higher than the atmospheric pressure, the water temperature is increased, which has the effect of preventing the suction capacity of the treated water pump from being lowered, and a plurality of pressure adjustments set according to the water temperature. By switching the valve or changing to a control valve or the like whose pressure can be controlled by a temperature signal or the like, it is possible to obtain an atmospheric pressure fluctuation effect from normal temperature water to high temperature water without imposing a burden on the pump.
The range of air pressure fluctuation can be calculated by the float switch interval and the air chamber volume, but instead of using a point-type liquid level detector such as a float switch, it automatically uses a water level sensor that performs linear water level detection. It is also possible to control the differential pressure of atmospheric pressure variation by control.

FIG. 2g is a basic configuration for providing an atmospheric pressure variation effect as in FIG. 2f, but the water surface of the raw water tank (2) is located lower than the water surface of the treated water tank (1), so that the raw water pipe (3) A control valve is not required for this, and if there is a check valve (13), an atmospheric pressure fluctuation effect can be obtained.
When raw water replenishment becomes necessary, the raw water pump (42) is operated, and when the upper water level is reached, the raw water pump is stopped so that the pressure corresponding to the water level of the raw water tank is maintained while the raw water pump is stopped. This is because new raw water is not supplied until the pressure is reduced.
In addition, when a positive displacement pump such as a screw type or a plunger type is used as the water supply pump, both functions of the pump and the control valve can be realized by a single positive displacement pump.

[Embodiment 3]
FIG. 4a is a flow diagram of a deoxygenation apparatus using an injector type gas mixer, in which a gas-liquid separation mechanism is configured in multiple stages, and nitrogen utilization efficiency is increased.
In order to clarify the characterizing portion of the present embodiment, the control-related functions incidental to the present invention are omitted from the drawings and are described as operation descriptions.
(Multistage processing and number of processing stages)
In the present embodiment, the number of processing stages is four in order to effectively use nitrogen. As means for preventing nitrogen supersaturation, a vapor condensing effect, a processing gas circulation utilization and an atmospheric pressure fluctuation effect are performed. Multi-stage treatment means that high-purity nitrogen gas is used in the fourth-stage treated water tank (1d) as the final stage, and the used nitrogen gas is used in the third-stage treated water tank (1c). This is an effective method for improving the deoxygenation efficiency with a small amount of nitrogen gas.
Here, the theoretical nitrogen requirements for single-stage treatment and 2-6 stages are shown in Table 1.
As preconditions, the calculation is performed assuming that the purity of nitrogen gas is 99.9% and the dissolved oxygen concentration of the treated water after treatment is 0.5 ppm. The numerical value is the amount of nitrogen gas (NL) required per 1 m ³ of treated water, and the unit is NL / m ³ .

処理段数が増加するに従い理論窒素量は減少するが、４段を超えた辺りから１段辺りの減少量が少なくなる。
又、初期の溶存酸素濃度が低下すると、窒素使用量も減少し、水温５５℃付近では３段と４段処理の場合の使用量の差が小さくなり、水温８０℃付近では、２段と３段との差が少なくなる。

As the number of treatment stages increases, the theoretical nitrogen amount decreases, but the reduction amount from around four stages to one stage decreases.
In addition, when the initial dissolved oxygen concentration decreases, the amount of nitrogen used also decreases. When the water temperature is around 55 ° C., the difference between the amounts used in the three-stage and four-stage treatments becomes small. The difference with the stage is reduced.

(Description of water supply system)
The water supply system sucks the raw water stored in the raw water tank (2) through the first-stage flow path switching valve (33a) by the first-stage treatment water tank pump (41a) and supplies the first-stage treatment tower (6a) with water. . The first-stage treated water tank (1a) has a float switch (43), and the upper-stage signal switches the first-stage flow path switching valve to the flow path from the first-stage treated water tank.
The raw | natural water which flowed in flows into a 1st stage contact tower (6a). Although not shown in the figure, a watering plate as in Embodiment 2 is installed at the upper part of the contact tower, and raw water is dropped to increase the contact efficiency.
The contact efficiency due to the steam condensation effect is extremely high, so even if a special watering mechanism or gas-liquid contact mechanism is not provided, a sufficient effect can be expected, but in order to improve the gas-liquid contact efficiency when there is no steam It is also effective to provide a gas-liquid contact portion with good performance according to the use frequency and the amount of treated water.
The water that has flowed down is stored in the first-stage treated water tank (1a).
The water stored in the first-stage treated water tank is supplied from the second-stage treated water tank (1b) through the first-stage treated water pipe (31a) by the second-stage treated water tank pump (41b) from the second-stage flow path switching valve (33b). ).
When the upper limit of the second-stage treated water tank is reached or the lower limit of the first-stage treated water tank is reached, the flow path of the second-stage flow path switching valve is changed to the flow path from the second-stage treated water tank (1b). By switching, the liquid level control of the tank can be realized.
The third-stage flow path switching valve (32c) performs the same control, and performs the liquid level control of the third-stage treated water tank (1c).
Since the fourth-stage treated water tank (1d) also serves as a buffer tank for supplying treated water to the outside, in order to increase the capacity, the treatment in the tank is used instead of the contact tower.
In the float switch (43) of the fourth stage water tank, a protection circuit can be provided to prevent the boiler from becoming a low water level by sending an alarm to the outside when the water level becomes extremely low.
Regarding the water transfer from the third-stage treated water tank to the fourth-stage treated water tank, the pressure of the nitrogen gas is high, and after premixing steam and nitrogen, the drive energy of the fourth-stage steam ejector (24d) can be used. Therefore, it is changed to a type that can inhale liquid and gas at the same time, and is transferred by an ejector.
In this case, the water surface control of the fourth stage treated water tank can be performed by the fourth stage steam cutoff valve (22d).

(Explanation of nitrogen system)
The nitrogen line system regulates the nitrogen gas stored in the nitrogen cylinder (14) and then supplies the nitrogen gas to the steam pipes after the fourth stage steam cutoff valve via the nitrogen cutoff valve (16).
This is because the first-stage nitrogen is supplied from a cylinder, so the pressure is high, and it is possible to reduce the consumption of steam by using it as energy for ejector operation, and some steam is processed during ejector operation. Although it is absorbed by water, gas-liquid contact can be performed at this time, and the processing efficiency is improved.
The fourth-stage treatment gas circulation pipe (17d) is a means for increasing the gas-liquid contact by returning the gas separated from the gas-liquid in the fourth-stage treatment water tank to the ejector section again. When the efficiency of each stage is improved, the supply amount of nitrogen to the treatment system decreases drastically (the supply amount of nitrogen to the treatment system is 5% by volume with respect to 1 m ³ of treated water). Reduced to an amount of about). When the amount of gas decreases, the volume of the liquid phase increases and the efficiency of gas-liquid contact deteriorates. Therefore, it is possible to prevent a reduction in processing efficiency by repeatedly performing circulation.
The amount of nitrogen gas circulation is generally 20% or more in terms of volume ratio of gas to liquid.
The fourth stage treated water tank exhaust pipe (11c) is connected to the outlet of the third stage treated water tank pump (41c) via the check valve (13).
When the atmospheric pressure of the 4th stage treated water tank rises due to the inflow of treated water into the 4th stage treated water tank, the treated nitrogen gas is sent to the 3rd stage side, but treated water is supplied without replenishment of treated water. Then, the water level is lowered, and the air chamber pressure of the fourth-stage treated water tank is lowered, so that an atmospheric pressure fluctuation effect can be provided.
The reason why the connection point is in this position is that when the third stage steam injector (24c) is always operating, there is no problem even if it is connected to the third stage processing gas circulation pipe (17c). This is because if the supply of steam is stopped due to an increase in the water temperature or the pump is stopped, the steam is exhausted via the third-stage treated water tank exhaust pipe (11b) and is not supplied into the third-stage contact tower.
In such a path, the nitrogen gas having a reduced purity flows back and forth in the second and first stages, and is exhausted to the outside air through the nitrogen exhaust pipe (12).

(Explanation of steam system)
In the steam system, steam that has been pressure-regulated from steam generated from the boiler (51) is connected in parallel to the first-stage steam cutoff valve (22a) to the fourth-stage steam cutoff valve (22d) via the steam pipe (21). To be supplied.
For example, in the case of the first stage steam cutoff valve (22a), the steam cutoff valve is opened or closed when the raw water pump (42) is stopped or when the water temperature of the first stage treated water tank (1a) is increased.
The second-stage to third-stage steam shut-off valves operate in the same manner, but in the fourth-stage steam shut-off valve (22d), the fourth-stage steam injector (24d) also has a pump function. Open / close operation is performed in accordance with the control operation.
In the present embodiment, it is assumed that raw water at room temperature is degassed as boiler feed water.
Therefore, preheating the feed water is beneficial for boiler operation and there is no loss of steam heat.
Since the fourth stage treated water tank (1d) is directly supplied to the boiler (51), maintaining the water temperature at an appropriate water temperature in accordance with the above-mentioned standard can be used together with the supply air preheating effect and the water temperature rises. It is possible to expect an increase in processing efficiency according to Henry's law.
In the case of a facility in which the drainage of used steam is recovered in the raw water tank (2) and the water temperature exceeds the above-mentioned appropriate water temperature, the fourth-stage treated water tank (1d) is placed in the first stage to Change to a water-drop type gas-liquid contact method similar to the third stage, or because the dissolved oxygen decreases and the required nitrogen amount also decreases due to a rise in water temperature, change to a three-stage process instead of a four-stage process. Is also possible.
(Nitrogen supply form)
In this embodiment, the nitrogen supply is a nitrogen cylinder (14). However, the use of liquid nitrogen or nitrogen gas from a nitrogen generator using a nitrogen separation membrane or molecular sieve activated carbon has the same effect.

(Processing performance)
The origin of the deoxygenation treatment according to this embodiment is as follows.
1st stage treated water tank to 3rd stage treated water tank Effective volume: 51L
Fourth stage treated water tank effective volume: 71L
Processing flow rate: 2500 L / h
Rated transit time: 108 seconds Single-stage transit time (average): 27 seconds Rated steam consumption: 10 kg / h
Nitrogen purity: 99.9% by volume
The following measured values were obtained for performance.
Inlet water temperature: 25 ° C
Outlet water temperature: 27 ° C
Inlet dissolved oxygen: 8.5 vol ppm
Treated water-soluble oxygen: 0.5 volume ppm
Theoretical nitrogen consumption: 48 L / m ³
Nitrogen consumption: 50 L / m ³
Processing efficiency: 98%
Final stage outlet exhaust oxygen concentration: 10.5% by volume
At this time, the predicted final stage outlet exhaust oxygen concentration at a processing efficiency of 100% is 11.1% by volume, and it is understood that the oxygen concentration is almost appropriate considering the processing efficiency.
Incidentally, when the processing efficiency is deteriorated, the oxygen concentration is further lowered, and when the outside air is mixed, the oxygen concentration is increased, both of which are factors for increasing the dissolved oxygen. Therefore, by issuing an alarm when the oxygen concentration is 9% by volume or less and the oxygen concentration is 12% by volume or more, a zirconia oxygen concentration meter or magnetic dumbbell can be used without using a dissolved oxygen meter with restrictions on reliability and temperature conditions. Abnormalities can be quickly discovered using a portable oximeter.

(Example of changing the number of dynamic processing stages depending on the water temperature)
FIG. 4b is an example of a flow in the case where the number of processing stages is dynamically changed according to the water temperature in the deoxygenation apparatus of FIG. 4a.
Only the parts that have changed are described.
When the raw water temperature sensor (80) is installed on the path of the raw water pipe (3) and the water temperature is approximately 50 ° C. or lower, the one-stage bypass switching valve (34a) is connected to the one-stage treated water tank and the two-stage flow. A flow path communicating with the path switching valve is formed.
When the water temperature exceeds 55 ° C, the flow path of the first-stage bypass switching valve is switched to the first-stage bypass pipe (35a) side, and the first-stage steam cutoff valve (22a) and the first-stage treated water tank pump (41a) stop operating, The first-stage flow path switching valve (33a) switches to the flow path from the first-stage treatment tank (1a).
When the temperature further increases, the number of processing stages can be further reduced by providing a bypass switching valve between the second stage processing tank and the third stage processing tank.
This configuration prevents heat loss by preventing wasteful heat dissipation from the contact tower and storage tank when the water temperature rises and gas solubility decreases and the benefits of multistage processing are small. can do.
When the water temperature is low, even if the number of processing stages is increased, heat loss due to heat dissipation is small, and conversely, the merit of multistage processing by reducing nitrogen gas is superior.
The line of the third stage treated water tank exhaust pipe (11b) is desirable as it is.
That is, the treated gas when the number of treatment stages is small has a low oxygen concentration, passes through the treatment tower and the treatment water tank, and keeps the dissolved oxygen concentration of the treatment water in the suspended tower low in the process of being discharged to the outside air. It is because it can.

(Example of using steam power equipment in the processing gas circulation line)
FIG. 4c shows an example in which the steam injector of FIG. 4a is changed to a steam-type turbo compressor, and only the components of the first-stage treated water tank section are shown for simplifying the explanation.
The water supply system is the same as in FIG. 4a. The nitrogen gas system is substantially the same, but since a steam turbo compressor (72) can be used, nitrogen gas can be injected into the raw water outlet with high pressure.
Therefore, even if the second-stage treated water tank exhaust pipe (11a) and the first-stage treated gas circulation pipe (17a) are merged, no short path occurs even when the steam turbo compressor (72) is stopped.
In the steam line, steam that passes through the first-stage steam shut-off valve (22a) is used to circulate the processing gas in the steam turbo compressor (72). Is absorbed by the fluid in which the processing gas is mixed with the raw water flowing down through the first-stage contact tower (6a) via the vapor absorption pipe (74).
Since this part forms a siphon, the pressure is negative. When exhaust steam flows into this part, the steam condenses under negative pressure, improving the gas-liquid contact efficiency and at the same time the steam compressor. As for efficiency, the energy that can be taken out is larger than that exhausted into the atmosphere.
However, when the water temperature is high or when there is no raw water supply, it is possible to use only the compressor function by exhausting the steam exhaust switching valve (73) to the steam exhaust pipe (75) side.
In addition, with a screw, piston, diaphragm, etc. as the drive side, a steam engine that uses steam can operate an aerator or operate a treated water pump, etc. Improvements can be realized.
In addition, when there is no steam, nitrogen gas can be circulated even when there is no steam by exhausting outside using compressed air instead of steam in this embodiment, and when there is no steam In applications that do not want to use steam or steam, it is possible to circulate using an electric fan, an electric compressor, or the like.

FIG. 4d simplifies the function of FIG. 4b using the treated water communication pipe (37) and the first-stage treated water tank pump (41a) to the fourth-stage treated water tank pump (41d).
The treated water communication pipe is connected to the first-stage treated water circulation pipe (36a) connected to the first-stage treated water pipe (31a) from the first-stage treated water tank (1a) and connected to the first-stage treated water tank pump on the upstream side. This is the same structure in the second and subsequent stages, and is connected to the treated water pump (46) and supplied to the process.
The raw water is pressurized by the raw water pump (42), and the water flow is controlled by the raw water control valve (45).
The feature of this embodiment is that the circulation flow rate of the first-stage treated water tank pump to the fourth-stage treated water tank pump is larger than the discharge amount of the treated water pump and the maximum flow rate of the raw water control valve.
For this reason, while each treated water tank pump is in operation, the direction of the treated water communication pipe flows toward each treated water circulation pipe, and the raw water or water from the previous stage passes through the treated water tank pump, the contact tower, and the treated water tank. Therefore, it will follow the path that flows out to the treated water piping, and no short path will occur.
That is, the amount of water flowing back through the communication pipe from the connection point of the treated water pipe is reduced by the amount of treated water supplied to the subsequent stage, thereby balancing the water level of each treatment tank.
For this reason, control of the level of the treatment water tank may be performed by detecting and controlling the level of any one of the treatment tanks even in the case of four-stage treatment, and the control can be simplified.
Even when the number of treatment stages is dynamically increased or decreased by a signal from the raw water temperature sensor (80), for example, when the first-stage treatment water tank pump is stopped, the first-stage contact tower (6a) and the first-stage treatment water tank (1a) Bypassing and supplying water directly to the second stage treated water tank (41b), the bypass circuit can be simplified.
When bypassing, if the first stage steam shut-off valve (22a) is stopped, consumption of useless steam can be prevented, but the second stage treated water tank exhaust pipe (11a) Since it is exhausted to the outside via the system, the dissolved oxygen concentration in the first-stage treated water tank can be kept low, and the risk of the dissolved oxygen concentration rising at the start of the next operation is eliminated.
The final stage of the treated gas is discharged to the outside through the nitrogen exhaust pipe (12), but it can be controlled by the exhaust solenoid valve (47) whether it is through the exhaust pressure adjustment valve (48) or directly exhausted. It has become.
This is to prevent cavitation due to insufficient suction capacity of the treated water pump (46) when the water temperature rises and the water vapor pressure rises. In addition to being controlled in two stages in this way, the water vapor calculated from the water temperature It is also possible to change the set pressure linearly according to the pressure.
Water level control can provide an atmospheric pressure fluctuation effect by changing the water level by closing the raw water control valve at the upper limit of the float switch (43) and opening it at the lower limit.
FIG. 4e is the same as the flow of FIG. 4d, except that the communication pipe is part of the treated water tank. As in FIG. 4d, the gas-liquid contact operation is performed only when the treated water pump is operated. Even when the treated water pump is not operated, the raw water or the treated water in the previous stage is circulated in the treated tank. Yes.
With such a configuration, in applications where bypass operations frequently occur, the temperature difference between the water temperature of the treated water tank that is not treated and the temperature of the water being treated can be reduced. The oxygen concentration can be stabilized.
FIG. 4f shows a check valve arranged in the middle of the communication pipe path of FIG. 4d. In this way, by inserting a check valve between the treated water pipe connection part of the communication pipe and the treated water pump of the next stage, it is possible to prevent a back flow of treated water in the latter stage during stoppage or when the treated water flow rate is low. The purity of the treated water can be maintained when the treated water is intermittently supplied or when the supply is stopped.
However, if a check valve is inserted on the path of the treated water communication pipe (37) in this way, the water level in the subsequent treated water tank rises by the amount of pressure loss that the circulation pump returns to the treated water tank via the treatment tower. , It will be fixed. In other words, since the water level in the first-stage treated water tank becomes the lowest, in such a case, the tank depth is adjusted so that fluctuations in the water level can be tolerated, or supplied to the next stage by the level adjustment exhaust solenoid valve (49) By adjusting the amount of the processing gas to be produced, it becomes possible to maintain the water level at each stage appropriately.
Since the level adjustment exhaust solenoid valve may be a small solenoid valve, the equipment cost is much lower than that provided with the water amount adjustment valve.

[Embodiment 4]
Hereinafter, a fourth embodiment of the present invention will be described with reference to the drawings.
FIG. 5 shows an embodiment of a system that automatically adjusts the amount of nitrogen gas according to the temperature of the treated water and has a function of supplying water to the boiler before starting the boiler that cannot use steam.
Although the flow of the two-stage deoxygenation apparatus is shown for the sake of simplicity of explanation, even if the number of stages is larger than that, there is no problem and the effect of reducing the consumption amount of nitrogen gas becomes larger.
(Water supply system)
The water supply system is substantially the same as in the third embodiment, but in order to increase the processing efficiency when the steam line cannot be used and at partial load, a treated water circulation valve is provided at the outlet of the first stage treated water tank pump (41a). When (44) is installed and the second-stage treated water tank (1b) is replenished, the first-stage treated water pipe (31a) side is used. The flow path is configured to be switched.
In addition, the feed water flow meter (5) which outputs the feed water flow rate to a deaeration apparatus is installed in the inlet of the unit.
(Nitrogen)
The nitrogen-based piping is supplied from the nitrogen tank (14) to the second-stage contact tower (6b) via the nitrogen solenoid valve (16) and the nitrogen flow meter (15).
The nitrogen gas exhausted from the second stage treated water tank (1b) is connected to the first stage steam injector (24a) via the second stage treated water tank exhaust pipe (11a).
The gas separated from the first stage treated water tank (1a) is also connected to the first stage steam injector (24a) via the first stage treated gas circulation pipe (17a). Therefore, when the pressure in the second-stage treated water tank (1b) becomes higher than the pressure in the first-stage treated water tank (1a), the corresponding nitrogen gas is supplied to the first-stage contact tower (6a).

(Water temperature automatic adjustment control)
In the arithmetic and control circuit (82), the purity of nitrogen gas to be used and the target dissolved oxygen concentration value are set in advance.
When the temperature of the treated water temperature sensor (83) is sent to the arithmetic control circuit (82), a calculation is performed to obtain a saturated dissolved oxygen concentration converted from the temperature inside, and in the case of this system, it is a two-stage process. Therefore, the necessary theoretical nitrogen amount can be obtained from the data table for converting the raw water-soluble oxygen into the treated water-soluble oxygen in the case of the two-stage treatment.
When the vapor pressure switch (23) is also normal, the target nitrogen injection rate is obtained assuming that the processing efficiency is about 98%.
When the raw water passes through the feed water flow meter (5), a flow rate signal is sent to the arithmetic control circuit (82) according to the passing amount, so that when a constant flow rate flows, the target injection rate is reached. Nitrogen gas can be injected into the second stage processing tower at the target nitrogen gas injection rate by opening the nitrogen solenoid valve.
In the case of a small amount of gas such as nitrogen, it is possible to perform proportional control by opening and closing the direct acting solenoid valve, but this is changed to one that can be linearly controlled such as a control valve. May be.
The nitrogen flow meter (15) is provided to monitor whether the amount of nitrogen gas is correctly controlled. It can also control the flow rate more accurately and alerts when the nitrogen gas is exhausted. It is also possible to put out.
In addition, when the water supply flowmeter (5) is configured at a lower cost, it can be replaced by an open / close signal of the float switch (43).
In that case, if the raw water pump (42) and the first-stage treated water tank pump (41a) are not operated simultaneously, the flow rate can be detected more accurately.

(Process when there is no steam)
When the steam pressure switch (23) is OFF, there is no steam. In that case, the target nitrogen injection rate is based on the gas-liquid contact efficiency when there is no steam in the system. Need to be calculated.
However, in such a case, since the treated water flow rate is often lower than the rated value, the treated water circulation valve (44) is changed to the treated water circulation pipe (36) side, and the treated water is repeatedly treated with the first-stage treatment tower and the first-stage treatment tower. By circulating between the treatment water tanks, it is possible to compensate for a decrease in gas-liquid contact efficiency.
When there is no steam, the suction effect by the first stage steam injector (24a) is lost, and it is considered difficult to reuse the treated gas using the first stage processing gas circulation pipe (17a). Since the steam injector is located at the top of the raw water pipe (3), when the steam is not supplied to the buffer chamber (27), the first-stage contact tower (6a) is filled with circulating water. Since the siphon is formed, the gas can be circulated, and the treated gas can be circulated and used even without steam.
In addition, this circulation becomes a partial load, and can be used to maintain the processing efficiency with the steam valve closed when the water temperature rises excessively when steam is used.
The raw water is controlled so that the raw water control valve (45) is closed at the high level of the float switch (43) of the first-stage treated water tank (1a) and opened at the low level. An atmospheric pressure fluctuation effect can be provided.
This atmospheric pressure fluctuation effect can eliminate the supersaturated state by giving the atmospheric pressure fluctuation effect to the second-stage treated water tank (6b) communicating with the second-stage treated water tank exhaust pipe (11a).
As described above, in the present embodiment, even in a situation where there is no steam, it is possible to provide the circulation utilization of the processing gas and the atmospheric pressure fluctuation effect, so that the treated water with the dissolved oxygen concentration suppressed is supplied to the boiler (51). Therefore, a highly practical deoxygenation device can be configured.

[Use range of target gas]
A typical target gas used in the present invention is nitrogen gas for the purpose of deoxygenation treatment.
However, since the gas-liquid contact method according to the present invention is extremely efficient, it can be expected to be used in the following applications.
(High oxygen concentration water)
By treating a gas having a high oxygen concentration using an oxygen-enriched membrane or the like with this apparatus, treated water having a concentration higher than the dissolved oxygen concentration at the same temperature can be obtained.
Highly dissolved oxygen water can be used for oxygen supply in general fish farms, and can also be used for activated sludge treatment and eutrophication measures for lakes and marshes.
(High concentration ozone water)
High ozone-containing water can be efficiently produced from ozone gas generated by an ozone generator or the like.
The high ozone content water can be used for various sterilization applications.
(Rare gas-containing water)
In the case of applications such as semiconductor processes and chemical synthesis using ultrapure water, nitrogen may be an impurity, and treated water containing rare gases such as He, Ne, Ar, etc. It may be necessary.
Even in such applications, the present invention can be processed with a small amount of the target gas, so that the cost can be reduced.
In addition to the above, the present invention can be widely applied to applications where it is desired to obtain treated water having a target concentration by using a target gas exhibiting gas-liquid dissolution characteristics in accordance with Henry's law.

[Deoxygenation technology]
(For steam boiler)
For deoxygenation of boiler feed water, classic steam deaerators, membrane deaerators, nitrogen deaerators, etc. have already been put to practical use, and the fields of use are extremely wide.
In particular, a physical deoxygenation method is suitable for applications that dislike impurities such as chemical substances in steam in the food and pharmaceutical fields.
However, each of the conventional methods has problems, and there is a need for a system with higher efficiency and reliability.
(Sealed water system)
The sealed water system is a system in which cold / hot water or the like is heat-exchanged at a use point and used for air conditioning or the like, but corrosion prevention has been a major issue.
If a compact system with high nitrogen use efficiency can be provided as in the present invention, the use application can be expanded even in such applications.
(Hot water system)
In the hot water supply system, corrosion prevention by chemicals is extremely limited, and water passing is one pass. Therefore, in the case of a conventional system with low nitrogen utilization efficiency, the running cost is high and the spread is not progressing.
Combining this method with a nitrogen generator or the like that can supply nitrogen at a low cost makes it possible to prevent corrosion at a reduced processing cost and promote the spread.

[Effective use of steam energy]
The steam used in the present invention has the following four effects. Further, the steam energy input can be recovered in the same manner as the pre-heating of the feed water in the case of boiler feed water or hot water supply. In addition, it is a processing method with high energy use efficiency.
(Water vapor condensation effect)
When water vapor condenses, it gives energy to the supersaturated gas in the water and promotes separation of dissolved gas into the air.
(Target gas reduction effect due to water temperature rise)
As the water temperature rises, the gas solubility decreases according to Henry's law, so that a reduction effect of the processing gas can be expected particularly for the purpose of deoxygenation.
(Use of kinetic energy of water vapor)
Since negative pressure can be created using the kinetic energy of high-pressure steam, recycled gas can be transferred to the high-pressure section without using a special device such as a compressor. The power of can also be used without using electrical energy.
(Recovery of steam energy)
In the case of boiler water supply, the following two conditions can be considered.
Case 1: When the feed water temperature is lower than the boiler room temperature.
When the boiler room temperature is 25 ° C. and the feed water temperature is 20 ° C. Assuming that the amount of nitrogen gas required for 1 m ³ treated water is 60 L and the steam used for the treatment is 10 kg, the temperature rise of the treated water is 4 ° C. Therefore, the piping system does not tend to dissipate heat, and all the heat of steam can be recovered.
Case 2: When the feed water temperature is higher than the boiler room temperature.
In such a case, there are many cases where the water supply line is kept warm, and when the temperature rises about several degrees, the heat loss via the heat keeping is very small, so most of the input heat can be recovered.
[Effective use of energy from water supply pump]
Since the minute pressure fluctuation used in the pressure fluctuation effect of the present invention is a technology that can be realized without using a special device such as a compressor or a vacuum pump, it is useless by utilizing the suction capability of the conventional water supply pump. Gas-liquid separation of supersaturated gas can be promoted without using power.
In particular, a pressure change using a liquid is an incompressible fluid unless accompanied by a gas motion such as cavitation or bubble compression, and thus has high volumetric efficiency and is advantageous in terms of energy.

DESCRIPTION OF SYMBOLS 1 ... Treated water tank 1a ... 1st stage treated water tank 1b ... 2nd stage treated water tank 1c ... 3rd stage treated water tank 1d ... 4th stage treated water tank 2 ... Raw water tank 3 ... Raw water piping 3a ... Raw water piping bypass valve secondary side 4 ... Treated water 5 ... Feed water flow meter 6 ... Contact tower 6a ... First stage contact tower 6b ... Second stage contact tower 6c ... Third stage contact tower 6d ... Fourth stage contact tower 7 ... Sprinkler plate 8 ... Vent pipe 9 ... Inner pipe 10a ... treated water tank high liquid level 10b ... treated water tank low liquid level 11 ... nitrogen pipe 11a ... second stage treated water tank exhaust pipe 11b ... third stage treated water tank exhaust pipe 11c ... fourth stage treated water tank exhaust pipe 12 ... nitrogen exhaust pipe DESCRIPTION OF SYMBOLS 13 ... Check valve 14 ... Nitrogen cylinder 15 ... Nitrogen flow meter 16 ... Nitrogen shut-off valve 17a ... First stage processing gas circulation pipe 17b ... Second stage processing gas circulation pipe 17c ... Third stage processing gas circulation pipe 17d ... Fourth stage Process gas circulation pipe 20 ... Steam source 21 ... Steam pipe 22 ... 1st stage steam shut-off valve 22b ... 2nd stage steam shut-off valve 22c ... 3rd stage steam shut-off valve 22d ... 4th stage steam shut-off valve 23 ... Steam pressure switch 24 ... Steam injector 24a ... 1st stage steam shut-off valve 24b ... 2 Stage steam injector 23c ... Third stage steam injector 24d ... Fourth stage steam injector 25 ... Automatic gas vent valve 26 ... Gas mixer 27 ... Buffer room 28 ... Screen 29 ... Gas separation room 31 ... Raw water piping 31a ... First-stage treated water piping 31b ... Second-stage treated water piping 31c ... Third-stage treated water piping 32 ... Treatment water piping 33a ... First-stage flow switching valve 33b ... Second-stage flow switching valve 33c ... Third-stage flow switching valve 33d ... Four-stage flow path switching valve 34a ... Single-stage bypass switching valve 34b ... Two-stage bypass switching valve 35a ... Single-stage bypass pipe 35b ... Two-stage bypass pipe 36 ... Treatment water circulation pipe 36 ... 1st stage treated water circulation pipe 36b ... 2nd stage treated water circulation pipe 36c ... 3rd stage treated water circulation pipe 36d ... 4th stage treated water circulation pipe 37 ... Treated water communication pipe 41a ... 1st stage treated water tank pump 41b ... 2nd stage treated water tank Pump 41c ... Third stage treated water tank pump 41d ... Fourth stage treated water tank pump 42 ... Raw water pump 43 ... Float switch 44 ... Treated water circulation valve 45 ... Raw water control valve 46 ... Treated water pump 47 ... Exhaust solenoid valve 48 ... Exhaust pressure adjustment Valve 49 ... Level adjusting exhaust electromagnetic valve 61 ... Steam inlet 62 ... Steam nozzle 63 ... Diffuser section 64 ... Outlet section 65 ... Suction section 66 ... Contact pipe 67 ... Steam hole 70 ... Steam type liquid spray nozzle 71 ... Injection hole 72 ... Steam turbo compressor 73 ... Steam exhaust switching valve 74 ... Steam absorption pipe 75 ... Steam exhaust pipe 80 ... Raw water temperature sensor 82 ... Calculation system Circuit 83 ... treated water temperature sensor 84 ... control wiring

Claims (12)

In the gas-liquid contact method in which the target gas and the treated water are brought into contact with each other at the gas-liquid contact portion of the gas-liquid contact device, the amount of the newly supplied target gas is 10 times or less the total amount of the hardly soluble gas contained in the treated water. In the case of the following processing (i) to (iii):
(I) treatment to make the gas phase of the gas-liquid contact portion supersaturated with water vapor,
(Ii) A process in which the separation gas is recycled and the volume mixing ratio of the gas to the treated water is 20%
(Iii) A depressurization step in which the gas phase pressure of the gas-liquid contact portion and the storage tank communicating therewith is lower than the pressure obtained by adding 95 KPa to the water vapor pressure at the average water temperature of the treated water, and preferably at least 10 KPa than the depressurization step pressure A process of performing one cycle or more while the treated water is present in the gas-liquid contact portion and the storage tank of each unit, with a pressurization step higher than 20 KPa as one cycle,
Among them, the process (i) is performed alone or in combination with the process (ii) or (iii), the process (ii) is performed in combination with the process (iii), or A gas-liquid contact method, wherein all of the treatments (i) to (iii) are performed. The gas-liquid contact method according to claim 1,
When carrying out the process (iii),
The gas-liquid contact device comprises:
When the pressure on the primary side becomes higher than the pressure on the secondary side or reaches a preset pressure, the processing gas is discharged out of the system. An airtight gas-liquid contact portion having an exhaust means with an adjusted backflow prevention means,
Provided with raw water control means at the raw water inlet part of the gas-liquid contact part, or provided with raw water supply means with the pressure of the water supply source being lower than the lower limit pressure,
The treated water outlet is provided with a feed water transfer means having a suction capacity of 1 m or more. A gas-liquid contact method characterized by changing the volume ratio of the gas phase to the water phase in the gas-liquid contact portion to cause a change in atmospheric pressure by controlling with the raw water supply means. In the gas-liquid contact method according to claim 1 or 2,
The gas-liquid contact portion;
Treated water supply means for supplying the treated water to the gas-liquid contact portion;
Target gas supply means for supplying the target gas to the gas-liquid contact portion;
Treated water intake means for causing the treated water to flow out from the gas-liquid contact portion;
A gas-liquid contact means comprising a target gas discharge means for discharging the target gas from the gas-liquid contact portion,
By connecting the treated water lines in multiple stages in series, supplying the high purity target gas to the last component of the treated water, and using the target gas discharged there as the supply gas for the previous component, the target In multistage gas-liquid contact treatment that reduces gas consumption,
When the dissolved gas contained in the raw water of the treated water is substantially consistent with the saturation state of the raw water temperature, and the average temperature of the raw water is relatively stable,
When the average temperature is 55 ° C. or lower, four stages,
When the average temperature is more than 55 ° C and not more than 80 ° C, three steps,
When the average temperature is more than 80 ° C. and less than 90 ° C., two steps,
When the average temperature is 90 ° C. or higher, multistage treatment is not selected.
Based on the processing stage number standard, adjust the number of processing stages,
When the change in the average temperature of the treated raw water is large,
From the lowest temperature to the number of processing stages based on the processing stage number criteria,
Bypass means for bypassing the treated water flow path of each treatment stage, and at least one of power source cutoff means for gas-liquid contact, and temperature detecting means for detecting the temperature of the treated water,
Controlling the number of processing stages by controlling at least one of the bypass means and the power source shut-off means when the temperature of the treated water detected by the temperature detection means reaches a preset water temperature. A gas-liquid contact method characterized by the above. In the gas-liquid contact method according to any one of claims 1 to 3,
When performing the process (i),
The gas-liquid contact device comprises:
Water vapor supply means for supplying the water vapor;
Target gas supply means for supplying at least one of a target gas supplied from the outside or a contacted target gas that has been gas-liquid separated; and
Water vapor target gas mixing means for preliminarily mixing the water vapor and the target gas from the water vapor supply means and the target gas supply means, and the mixed steam from the water vapor target gas mixing means are absorbed into the treated water in the gas-liquid contact portion Or a mixing vapor condensing means
In the case where the treated water and the target gas are mixed in advance in the gas-liquid contact part, the water vapor from the steam supply means is provided with water vapor condensing means for absorbing the treated water and the target gas in the mixed state, or ,
Comprising both said vapor condensing means,
The mixed liquid or the water vapor is condensed in the treated water in the gas-liquid contact part. In the gas-liquid contact method according to any one of claims 1 to 3,
When performing all of the processes (i) to (iii),
The gas-liquid contact device comprises:
As a liquid transfer means for supplying treated water into the gas-liquid contact portion, it is provided with a vapor-driven liquid transfer means using steam as drive energy,
As a means for transferring the target gas in the gas-liquid contact portion, it is provided with a steam-driven gas transfer means using steam as driving energy, or
As the agitation means of the treated water and the target gas in the gas-liquid contact portion, it comprises a vapor drive agitation means using steam as drive energy,
Vapor condensing means for absorbing treated water with water vapor with reduced kinetic energy from at least one water vapor driving means among the vapor driven liquid transfer means, the vapor driven gas transfer means and the vapor driven stirring means;
The following methods (i) to (iii):
(I) A method of previously mixing a target gas with water vapor for driving,
(Ii) a method of mixing the target gas before flowing into the vapor condensing means;
(Iii) A method in which treated water for absorbing water vapor is mixed with the target gas in advance.
A gas-liquid contact method, wherein a steam supersaturated state is present in the gas-liquid contact portion by any one of the methods. In the gas-liquid contact method according to claim 5,
The gas-liquid contact device comprises:
In part of the flow path of the treated water, provided with at least one detection means of a temperature detection means capable of detecting the temperature and a flow rate detection means capable of detecting the flow rate of the treated water,
Based on the temperature or flow rate of the treated water detected by the detecting means, the driving steam control means for controlling the supply of water vapor to the steam driving means, or the temperature or flow rate of the treated water detected by the detecting means A water vapor control means for condensing for controlling the supply of exercised water vapor to the vapor condensing means,
When the temperature of the treated water is equal to or lower than a predetermined temperature, when the flow rate of the treated water is equal to or higher than the predetermined flow rate, or when both conditions are satisfied, the water vapor to the water vapor driving means The gas-liquid contact method is characterized by supplying water or condensing exercised steam into treated water. In the gas-liquid contact method according to any one of claims 1 to 6,
The gas-liquid contact device comprises:
A temperature detection means capable of detecting the temperature and a flow rate detection means capable of detecting the flow rate of the treated water in the flow path of the treated water or the gas-liquid contact portion, and
When using water vapor, the system operation normality detection means determined from at least one of the steam detection means of the steam supplied to the processing equipment, the circulation target gas flow rate detection means, and the condensed steam flow rate detection means,
Saturated oxygen concentration calculating means for obtaining a saturated oxygen concentration from a signal from the temperature detecting means;
Necessary target gas amount calculation for calculating the required target gas amount per unit flow rate from the saturated oxygen concentration, the number of gas-liquid contact processing stages, the target gas purity, and the gas-liquid contact processing efficiency when the system operation is normal Means,
Proportional calculation means for calculating the required amount of the target gas according to the treated water flow rate based on the signal from the required target gas amount calculating means and the signal from the flow rate detecting means;
A target gas flow rate adjusting means for adjusting the target gas flow rate according to the treated water flow rate by a signal from the proportional calculation means,
A gas-liquid contact method characterized by automatically adjusting the target gas flow rate according to the flow rate of treated water, temperature, number of treatment stages, system state, and gas purity. In the gas-liquid contact method according to claim 7,
When the effect of the treatment (i) cannot be expected from the signal from the system operation normal detection means, according to the amount of treated water per unit time that can be handled only by the effect of the treatment (ii) and (iii), The gas-liquid contact method characterized in that the gas-liquid contact efficiency value of the required target gas amount calculation means is adjusted to a value smaller than that when the system is normal. In the gas-liquid contact method according to claim 7 or 8,
The gas-liquid contact device comprises:
In a gas-liquid contact means comprising a vertically arranged gas-liquid contact part and a storage tank having a liquid level lower than the uppermost part of the gas-liquid contact part, the gas-liquid contact part treated water falling part and storage It has a gas circulation line that communicates the air chamber of the tank,
There is provided a switching means for communicating the treated water outlet of the treated water supply means and the treated water inlet to the gas-liquid contact means at the outlet of the treated water supply means for supplying treated water to the gas-liquid contacting means or the treated water utilization facility in the subsequent stage. Or
Provided at the inlet of the treated water supply means for supplying treated water to the gas-liquid contact means is a switching means for communicating the treated water or raw water inlet from the preceding gas-liquid contact means and the treated water outlet from the gas-liquid contact means,
When there is no steam supply due to a signal from the system operation normal detection means, or when the temperature and flow rate of treated water is low and the steam power is shut off, the liquid transfer capability of the treated water supply means is used by the switching means. Then, the treated water in the gas-liquid contact means is circulated, and the air pressure in each stage is changed by adjusting the switching means from the previous stage and the switching means to the subsequent stage, and the falling part of the gas-liquid contact part A gas-liquid contact method characterized by circulating the separated processing gas by a siphon action formed on the substrate. In the gas-liquid contact method according to any one of claims 7 to 9,
The gas-liquid contact device comprises:
It has a channel that communicates from the raw water inlet to the treated water outlet,
A circulation channel that communicates the liquid circulation means inlet to the upstream side of the communication channel and returns the treated water stored in the treated water tank via the gas-liquid contact portion to the downstream side of the liquid transfer means inlet;
The circulation type gas-liquid contact device having a liquid circulation means having a transfer capacity larger than the flow rate of the maximum water supply of the gas-liquid contact device is configured in one stage, and the circulation type gas-liquid contact apparatus is configured in multiple stages,
At least one of the treated water tanks is provided with a liquid level detection means, and a flow rate control means is provided on the upstream side of the communication flow path. In the gas-liquid contact method according to any one of claims 1 to 10,
An inert gas is used as the target gas, and the gas composition in the treated water is replaced with the gas composition of the inert gas. The water deoxygenation method according to claim 11,
Oxygen concentration detection means for measuring the oxygen concentration of the exhaust gas supplied from the previous processing unit to the next processing unit or exhausted to the atmosphere;
The required target gas amount calculation means is provided with at least one stage of an oxygen concentration calculation circuit in the expected processing gas, and the oxygen concentration value of the oxygen concentration detection means is compared with the expected oxygen concentration calculation value at the same place An oxygen concentration comparison calculation circuit for performing
A method for deoxygenating water, wherein the oxygen concentration comparison operation circuit outputs either or both alarms when the oxygen concentration is too high or the oxygen concentration is too low.

Images