JP2013071047A - Microbubble generation device, and antifouling system for condenser using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a microbubble generation device, capable of regularly generating microbubbles in a stable manner even in an open flow passage such as a condenser taking in seawater from the open ocean, and an antifouling system for a condenser using the same.SOLUTION: In the test device 1, seawater taken from the open ocean by an intake pump 3 is passed through an ejector of the microbubble generation device 5, whereby air is sucked from the outside by the ejector to generate microbubbles in the seawater, and the seawater including the generated is further pressurized by a pressure pump 54 of the microbubble generator 5.

Description

  The present invention relates to an apparatus for generating fine bubbles in, for example, seawater and a condenser antifouling system using the apparatus.

  In a power plant, seawater is passed through a plurality of cooling capillaries housed in the fuselage using a steam turbine condenser for power generation, and heat is exchanged between the steam introduced into the fuselage and the seawater in the cooling capillaries. The water is cooled and condensed. During the operation of the condenser, slime and foreign substances gradually adhere to the inner surface of the cooling thin tube, so that the heat exchange efficiency gradually decreases, and the degree of vacuum decreases accordingly. It can lead to corrosion. As a result, the power generation efficiency of the power plant may be reduced.

  Accordingly, as in Patent Document 1, for example, a cleaning device has been developed that circulates and distributes a cleaning ball (sponge ball) through a cooling thin tube during condenser operation to remove slime, foreign matter, and the like in the tube.

  In this cleaning device, a sponge ball is introduced into a cooling water inlet pipe through which a cooling water is introduced into the cooling thin pipe through a ball injection pipe to wash the inside of the cooling thin pipe, and then a ball collection network installed in the cooling water outlet pipe is used. The ball is being collected. The balls collected by the ball collection net are taken out from the condenser through the ball take-out pipe, and are reintroduced into the cooling water inlet through the ball injection pipe by the circulation pump, so that the cooling thin tube is repeatedly washed. It has become.

  In this cleaning device, slime and foreign matter adhering to the inner surface of the cooling thin tube can be directly scraped off with a ball, but seaweed or balls adhere to the ball collection net, and before and after the condenser thin tube of the condenser. Since the differential pressure increased, there was a risk of hindering the operation of the steam turbine. Further, if the ball flows out to the open ocean, there is a risk of affecting the environment.

  For this reason, in recent years, various cleaning methods that do not use balls have been developed. For example, Patent Document 2 includes a high-pressure pump and an ejector, and includes a foaming unit that encloses a gas in a pressurized liquid to form a gas-liquid mixed fluid, and subdivides the bubbles in the gas-liquid mixed fluid into microbubbles. The microbubble supply section including the venturi tube and the part of the flow path through which the gas-liquid mixed fluid including the microbubble passes are squeezed, and the microbubbles are refined by rushing into the throttle so as to be ejected as nanobubbles. And a nanobubble generating device formed by the method described above.

  Moreover, in patent document 3, the stock solution which sucked gas with the ejector is pressurized with a pressurizing pump, and is supplied to the inflow side of the gas-liquid mixing device together with the compressed gas generated by the compressor, and the gas is mixed in the gas-liquid mixing device. The dissolved solution flowing out from the outlet is stored in a tank that can release excess gas contained in the dissolved solution, and the dissolved solution is decompressed from the supply port formed in the tank. There has been disclosed a fine bubble generating apparatus that can be appropriately taken out by reducing the pressure with a valve.

  However, in the above-mentioned Patent Document 2, a so-called sealed flow path that is sealed from the outside from the inlet to the foaming section, the microbubble supply section, and the nanobubble generation section to the outlet is provided, and the liquid is pumped from the upstream side. By doing so, the liquid is sent to the outlet without power. Therefore, it is difficult to apply to an open channel.

  Moreover, in patent document 3, although it can apply to an open flow path, the pressure fluctuation | variation in an inlet may have a big influence on ejector performance. Therefore, when the seawater is taken in from the open ocean as the cooling water for the steam turbine condenser for power generation at the power plant, the pressure at the inlet varies greatly due to sea level fluctuations. Performance cannot be ensured, and it is difficult to stably generate microbubbles.

  The present invention has been made in view of such circumstances. For example, even in an open channel such as a condenser that takes in seawater from the open ocean, microbubbles can be generated stably at all times. It is an object of the present invention to provide an apparatus and a condenser antifouling system using the apparatus.

  A first invention is an apparatus for generating fine bubbles by dissolving a gas in a liquid. The liquid pressurized by the first pump is passed through the ejector, and the ejector allows gas to be generated from the outside. Is sucked to generate fine bubbles in the liquid, and the liquid in which the fine bubbles are generated is further pressurized by a second pump. The liquid is seawater, fresh water, etc., and the gas is air, carbon dioxide, nitrogen, ozone, or the like.

  According to the first invention, by passing the liquid pressurized by the first pump through the ejector, the ejector sucks the gas from the outside to generate fine bubbles in the liquid, and the fine bubbles are Since the generated liquid is further pressurized by the second pump, a differential pressure before and after the ejector can be secured and a sufficient suction force can be obtained. Thereby, even if there is a large fluctuation in the liquid level on the water intake side, it is possible to maintain a good generation state of fine bubbles.

  Further, based on the differential pressure between the liquid inlet and the liquid outlet of the ejector, the first pump and the second pump are controlled, or the opening of the valves provided at both pump outlets is adjusted. It is preferable to provide a control device for performing the above.

  In this case, based on the differential pressure between the liquid inlet and the liquid outlet of the ejector, the first pump and the second pump are controlled, or the opening degree of the valves provided at both pump outlets Since the control device for adjusting is provided, the differential pressure before and after the ejector is automatically secured, and a sufficient suction force can be obtained.

  The second pump preferably has a plurality of blades.

  In this case, since the second pump has a plurality of blades, the fine bubbles generated by the ejector are sheared by the plurality of blades, thereby increasing the contact area between the fine bubbles and the liquid, and efficiently generating the fine bubbles. It can be dissolved in a liquid.

  Moreover, it is preferable to provide a tank downstream of the second pump.

  In this case, since the tank is provided on the downstream side of the second pump, the fine bubbles can be more efficiently dissolved in the liquid by giving the residence time in the tank to the sheared fine bubbles.

  Moreover, it is preferable that the tank is provided with a discharge part for discharging gas.

  In this case, since the tank is provided with a discharge portion that discharges gas, undissolved gas can be discharged from the liquid.

  Moreover, it is preferable to provide a throttle part immediately before the injection object of fine bubbles.

  In this case, since the throttling portion is provided immediately before the injection object of the fine bubbles, an appropriate amount of fine bubbles can be regenerated by adjusting the injection amount and releasing the pressure at the time of injection.

  Moreover, 2nd invention is equipped with the microbubble generator of any one of Claims 1-6, and injects the microbubble generated with this microbubble generator into a condenser, It is characterized by the above-mentioned. Related to the antifouling system of the condenser.

  According to the second invention, the fine bubble generating apparatus according to any one of claims 1 to 6 is provided, and the fine bubbles generated by the fine bubble generating apparatus are injected into the condenser. Antifouling of water containers can be achieved.

  According to the first invention, by passing the liquid pressurized by the first pump through the ejector, the ejector sucks the gas from the outside to generate fine bubbles in the liquid, and the fine bubbles are Since the generated liquid is further pressurized by the second pump, a differential pressure before and after the ejector can be secured and a sufficient suction force can be obtained. Thereby, even if there is a large fluctuation in the liquid level on the water intake side, it is possible to maintain a good generation state of fine bubbles.

  According to the second invention, the fine bubble generating apparatus according to any one of claims 1 to 6 is provided, and the fine bubbles generated by the fine bubble generating apparatus are injected into the condenser. Antifouling of water containers can be achieved.

It is a whole block diagram of the testing apparatus for investigating the basic performance of this invention. It is a block diagram of a microbubble generator. It is sectional drawing of an ejector. It is the whole block diagram of a condenser antifouling system based on the result in a test device.

  The microbubble means a fine bubble having a diameter of about 10 to 50 μm. Ordinary bubbles rapidly rise in the water and finally burst at the liquid level. However, since the microbubble has a fine bubble volume, the ascending speed is slow and the microbubble continues to stay in the liquid. Also, the microbubbles become smaller by pressurization, and the gas is effectively dissolved in water. Furthermore, since the microbubbles are negatively charged, the microbubbles repel each other. For this reason, it has various properties different from normal bubbles, such as no coupling between microbubbles and no reduction in bubble concentration.

  The present inventors actually produced a test apparatus for examining the basic performance of the steam turbine condenser antifouling system in a power plant by utilizing the properties of such microbubbles. FIG. 1 is an overall configuration diagram of the test apparatus 1. In addition, each element in FIG. 1 is each connected by piping shown as a continuous line, and the valve (V1-V5, V7) is interposed in those appropriate positions. Moreover, each pump and each sensor are each connected to the switchboard with the electric wire shown with a broken line.

  As shown in FIG. 1, the test apparatus 1 mainly includes a seawater filter 2, a water intake pump (corresponding to a first pump) 3, a strainer 4, a microbubble generator (corresponding to a microbubble generator). 5, a condenser thin tube model (corresponding to an injection target of fine bubbles) 6, 7 and a control panel (corresponding to a control device) 8.

  The seawater filter 2 is provided at a water intake under the sea surface WL for taking seawater from the open ocean and supplements and removes relatively large garbage such as jellyfish and shellfish in the seawater taken. is there.

  The intake pump 3 is, for example, a self-priming land pump, and transfers the seawater taken from the open sea through the seawater filter 2 to the condenser tube model 6 via the microbubble generator 5 described later in detail. At the same time, it is directly transferred to the condenser tube model 7 without passing through the microbubble generator 5.

  The strainer 4 is provided on the outlet side of the intake pump 3, and supplements and removes relatively small garbage in seawater discharged from the intake pump 3.

  The condenser narrow pipe models 6 and 7 simulate the cooling side of an actual condenser, and a plurality of thin pipes communicate between water chambers serving as seawater inlets and outlets as cooling water. . The capacity of the water chamber and the material, inner diameter, and length of the narrow tube are faithfully reproduced that of the actual machine.

  The control panel 8 captures detection signals from the start and stop of each pump and each sensor (pressure gauges P1 to P5, flowmeters F1 to F3, thermometers not shown) such as pressure, flow rate, and temperature. Can be recorded continuously.

  FIG. 2 is a configuration diagram of the microbubble generator 5, and FIG. 3 is a cross-sectional view of the ejector 53. This will be described below.

  The microbubble generator 5 mainly includes a seawater inlet 51, an air filter 52, an ejector 53, a pressure pump (corresponding to a second pump) 54, a pressure vessel (corresponding to a tank) 55, and a seawater outlet 56. It is composed of And by using air (atmosphere), there is no need for detoxification at the time of drainage, and by adopting an ejector method + pressure dissolution method considering the environmental load, the bubble diameter and the time until bubble collapse can be controlled. It is like that.

  The seawater inlet 51 is a part that takes in the seawater transferred by the water intake pump 3 via the strainer 4 into the apparatus, and is provided with a connecting portion such as a flange, for example.

  The air filter 52 is provided at a portion that takes in air from outside into the apparatus, and here, dust in the taken-in air is sufficiently removed.

  As shown in FIG. 3, in the ejector 53, the seawater W injected at a high speed from the nozzle 533 connected to the inlet 531 reaches the throat portion of the diffuser 534, while the air A sucked from the inlet 532 flows in. It is accompanied by the jetted seawater W and discharged from the outlet 535. Thereby, microbubbles are generated and can be mixed in the seawater W.

  The pressurizing pump 54 pressurizes seawater mixed with microbubbles to facilitate dissolving the microbubbles in seawater. Specifically, seawater mixed with microbubbles discharged from the ejector 53 is pressurized to about 0.39 MPa (4 Kg / cm 2) to promote dissolution of microbubbles. Further, as the pressurizing pump 54, a vortex type pump equipped with a plurality of blades is used. Thus, the microbubbles are sheared by a plurality of blades to reduce the bubble diameter, thereby further promoting the dissolution of the microbubbles.

  The pressurization container 55 gains pressurization time while flowing seawater containing microbubbles promoted by the pressurization pump 54 from the seawater inlet at the upper part of the main body and storing it in a pressurized state. The excess bubbles (gas) that could not be dissolved in the water are separated. For example, surplus bubbles are collected near the top and discharged to the outside from a vent valve (corresponding to a discharge unit) V6 provided there, while seawater from which excess bubbles are separated is discharged from the seawater outlet at the bottom of the main body. It is.

  The outlet 56 is a part that discharges the seawater discharged from the pressurized container 55 and dissolved with microbubbles to the outside of the apparatus, and is provided with a connecting portion such as a flange, for example.

  Hereinafter, the operation of the test apparatus 1 will be described.

  First, the water intake pump 3 is activated from the control panel 8, and seawater in the open ocean is taken in via the seawater filter 2. Then, a part of the taken seawater is transferred to the microbubble generator 5 through the strainer 4.

  Next, the microbubble generator 5 is activated, and the seawater transferred from the ejector inlet 51 through the strainer 4 by the intake pump 3 is taken into the ejector 53 in the apparatus.

  Then, as shown in FIG. 3, the seawater W is jetted at a higher speed than the nozzle 533 connected to the seawater inlet 531 of the ejector 53. The seawater W jetted at this high speed reaches the throat portion of the diffuser 534. At this time, external air A is sucked from the air inlet 532 of the ejector 53 through the air filter 52. The sucked air A is refined by the action of the seawater W jetted at a high speed, and microbubbles are generated in the seawater W. The seawater W mixed with the microbubbles is discharged from the seawater outlet 535.

  Next, the pressurizing pump 54 pressurizes the seawater mixed with the microbubbles, thereby facilitating dissolution of the microbubbles in the seawater. Specifically, seawater mixed with microbubbles discharged from the ejector 53 is pressurized to about 0.39 MPa (4 Kg / cm 2) to promote dissolution of microbubbles. In addition, the microbubbles are sheared by the blades of the pressure pump 54 to further promote the dissolution of the microbubbles.

  Next, seawater whose microbubbles are promoted by the pressure pump 54 flows from the upper inlet 552 of the main body 551 of the pressure vessel 55. Therefore, while storing in a pressurized state, the pressurization time is gained, and surplus bubbles that could not be dissolved in seawater are separated. Specifically, surplus bubbles are collected near the top and discharged to the outside from a vent valve 553 provided there, while surplus bubbles are separated and seawater is discharged from the lower outlet 554.

  And the seawater which isolate | separated the excess bubble discharged | emitted from the pressurization container 55 is discharge | released out of the apparatus from the seawater outlet 56. FIG. The seawater at this time is transparent, and the microbubbles appear as if they have disappeared.

  The discharged seawater is introduced into the inlet-side water chamber via a valve (corresponding to a throttling portion) V7 provided immediately before the condenser narrow tube model 6, passes through the narrow tube, and exits. Go to the water chamber on the side. At this time, an appropriate amount of microbubbles can be generated (regenerated) by adjusting the injection amount of the microbubbles with the valve V7 and releasing the reduced pressure at the time of injection. Then, while the generated microbubbles pass through the narrow tube, the slurry or the like attached to the narrow tube is removed. Since the pressure sensors P2 and P3 are attached to both water chambers, the detection signals from the pressure sensors P2 and P3 are taken into the control panel 8 and continuously recorded there. Seawater that exits the water chamber on the exit side is returned to the surface of the original open ocean.

  According to this test apparatus 1, the differential pressure before and after the ejector is secured by adjusting the capacity (pressure / flow rate) of each pump and adjusting the opening of each valve by manual operation. It turns out that power can be gained. Moreover, it was also possible to visually recognize the favorable generation state of microbubbles in the microbubble generator 5. That is, the seawater in which the microbubbles are dissolved at the time of exit from the microbubble generator 5 is almost transparent, and the dissolution thereof is promoted. And the seawater in the water chamber on the seawater inlet side of the thin tube model 6 was milky white, and it was confirmed that microbubbles were regenerated. However, since the test time is short at present, the difference in the antifouling effect between the thin tube models 6 and 7 has not been sufficiently confirmed yet and will be clarified in future tests.

  FIG. 4 is an overall configuration diagram of the condenser antifouling system 1a based on the results of the test apparatus. In this condenser antifouling system 1a, the elements different from the test apparatus 1 are given the suffix "a", and the common elements are given the same reference numerals, and redundant description is omitted.

  As shown in FIG. 4, this condenser antifouling system 1a mainly includes a seawater filter 2, a water intake pump (corresponding to a first pump) 3, a strainer 4, a microbubble generator (a fine bubble generator). And a pressurizing pump 54 corresponding to the second pump.) 5, a condenser (corresponding to the injection target) 6a and a control panel (corresponding to the control device) 8a. Yes.

  The condenser 6a is an actual condenser. Here, heat exchange is performed between the seawater flowing in the narrow pipe communicating between the water chambers and the high-temperature steam introduced into the body.

  The control panel 8a controls the intake pump 3 and the pressure pump 54 based on the differential pressure detected by the sensor Pd provided between the seawater inlet and the seawater outlet in the ejector 53 of the microbubble generator 5. Alternatively, the opening degree adjustment of the valve at each pump outlet may be automatically performed. Needless to say, a difference may be taken from the pressure detected by each of the two sensors.

  For this reason, the control panel 8a is provided with a CPU and a memory (not shown). Then, the CPU reads the program and data stored in advance in the memory, performs a predetermined calculation using the differential pressure detected by the sensor Pd, and generates a control signal based on the calculation result as the intake pump 3. And the pressurizing pump 54 to each driver (not shown), the control is performed, or the opening degree of a valve (not shown) at each pump outlet is automatically adjusted. In addition, the start and stop of each pump and the detection signals from each sensor (pressure gauges P1 to P3, flowmeters F1 to F3, thermometers not shown) such as pressure, flow rate, temperature, etc. are captured and recorded continuously This is the same as described above.

  According to the condenser antifouling system 1a of the present condenser, a differential pressure before and after the ejector 53 is automatically secured, and a sufficient suction force can be obtained. Thereby, even if there is a large fluctuation in the sea surface WL that takes in seawater, it is possible to maintain a good microbubble generation state in the microbubble generator 5. As a result, the good antifouling effect of the condenser 6a can be obtained.

  In the above embodiment, the liquid is seawater and the gas is air in consideration of the large amount of cooling water in the condenser 6a and the prevention of corrosion of the thin tubes, but there is no such problem. The liquid may be fresh water or the like, and the gas may be carbon dioxide, nitrogen or ozone.

  Moreover, in the said embodiment, although the antifouling | staining system 1a of the condenser was comprised using the microbubble generator 5, the application destination of this microbubble generator 5 is not limited to this. For example, it may be applied to the cultivation of oysters and water purification using the activation action of microbubbles on living organisms.

  Moreover, in the said embodiment, although it applied solely to the antifouling system 1a of a condenser, of course, you may use together with a ball-type conventional system.

1 Test apparatus 1a Condenser antifouling system 2 Seawater filter 3 Intake pump (corresponds to the first pump)
4 Strainer 5 Microbubble generator (corresponds to microbubble generator)
51 Seawater inlet 52 Air filter 53 Ejector 54 Pressurizing pump (corresponding to the second pump)
55 Pressurized container (corresponds to a tank)
56 Seawater outlet 6, 7 Condenser capillary model
6a Condenser (corresponds to the injection target)
8,8a Control panel (corresponding to the control device)
V6 Vent valve (corresponds to the discharge part)
V7 valve (corresponds to the throttle)
Pd sensor

JP 2010-169335 A JP 2011-121002 A No. 7-37702

Claims (7)

An apparatus for generating fine bubbles by dissolving a gas in a liquid,
By passing the liquid pressurized by the first pump through the ejector, gas is sucked from the outside by the ejector to generate fine bubbles in the liquid, and the liquid in which the fine bubbles are generated is A fine bubble generator characterized by further pressurizing with a pump.   Based on the differential pressure between the liquid inlet and the liquid outlet of the ejector, the first pump and the second pump are controlled, or the opening degree of the valves provided at both pump outlets is adjusted. The fine bubble generator according to claim 1, further comprising a control device.   The fine bubble generator according to claim 1 or 2, wherein the second pump has a plurality of blades.   The fine bubble generating apparatus according to any one of claims 1 to 3, wherein a tank is provided on the downstream side of the second pump.   The fine bubble generating device according to claim 4, wherein the tank includes a discharge unit that discharges gas.   The microbubble generator according to any one of claims 1 to 5, wherein a throttle portion is provided immediately before an injection target of microbubbles.   A condenser antifouling system comprising the fine bubble generator according to any one of claims 1 to 6 and injecting fine bubbles generated by the fine bubble generator into a condenser. .

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