JP4547445B2 - Liquid processing equipment - Google Patents

Description

  The present invention relates to a liquid processing apparatus using fine bubbles.

  The liquid treatment method using ozone includes the method described in [Non-patent Document 1]. The ozone injected into the water to be treated in the ozone reaction tank equipment is consumed by the reducing substances contained in the water to be treated. Among the injected ozone, the ozone in the bubbles that reach the water surface without dissolving in the water to be treated Is discharged into the air to become exhausted ozone, which is decomposed by the exhausted ozone treatment device. For this reason, the amount of ozone injected into the reaction vessel equipment includes the amount of ozone consumed to oxidize reducing substances and the amount of ozone discarded without being dissolved in addition to the amount of ozone necessary to achieve the target water quality. Need to add.

  The ozone treatment system used for water treatment includes pretreatment equipment, post-treatment equipment, ozone generation equipment, waste ozone treatment equipment, and the like in addition to ozone reaction tank equipment. Since the ratio of the power consumption in the ozone generating facility is the largest in the power consumption of the entire system, to improve the economic efficiency of the treatment system, it is necessary to reduce the ozone generation amount, that is, to improve the ozone utilization rate. Specifically, it is effective to reduce the reducing substances in the water to be treated and to improve the efficiency of ozone dissolution, that is, to reduce the amount of exhausted ozone.

  Here, the fine bubbles are bubbles having a diameter of about 50 micrometers or less. According to [Non-Patent Document 2], the bubbles in this region generally have a diameter according to the dissolution of the gas in the bubbles into the surrounding liquid phase. Therefore, due to the effect of surface tension, the inside becomes high pressure and high temperature, and when annihilating, free radicals having high oxidizing power such as OH radicals and pressure waves are generated. Moreover, since the specific surface area is large and the rising speed is small, the solubility of the gas in the liquid is high.

  For this reason, in the case of using fine gas bubbles with oxidizing power such as ozone for water treatment, in addition to the oxidizing power of dissolved gas, due to the oxidizing power of pressure waves and radicals generated when the fine bubbles disappear, cell walls, cell membranes, cytoplasm There is also a possibility that these are physically destroyed.

  As a conventional technique for performing water treatment using bubbles such as ozone, as described in [Patent Document 1], ozone is directly injected from an air diffuser installed in an ozone contact tank. There is one that recovers gas containing undissolved and unused ozone from the upper space.

  [Patent Document 2] discloses a method in which a gas is mixed as coarse bubbles, pressurized by a pump, and then injected into a contact tank through a decompression nozzle, whereby the injected gas is made into fine bubbles and injected into the contact tank. Has been. In [Patent Document 3], in the pressure reducing nozzle, the nozzle has a perforated plate shape, the number of holes through which the fluid passes is changed by the flow restricting plate, and the pump rotation speed is set so that the pressure upstream of the nozzle becomes constant. A fine bubble generator that stably generates fine bubbles by controlling the inverter is disclosed.

  Water treatment here refers to the removal of organic substances and microorganisms in the water to be treated by filtration, oxidative decomposition, etc., by injecting an oxidizing reagent or gas, or using light or electromagnetic wave irradiation or filtration. It means the process to do.

JP 2004-122105 A JP 2003-117365 A JP 2007-21392A "Ozone Handbook", Japan Ozone Association, 2004 “Characteristics of Water and New Utilization Technology”, NTS Corporation, pages 142-146, 2004

  According to the method described in [Patent Document 1], since a diffuser tube is used for injecting ozone, the bubble diameter is more than millimeter diameter and the dissolution efficiency is low. According to “New Technology for Utilizing Ozone”, Sanyu Shobo In order to obtain an ozone absorption efficiency of about 90% or more, a water depth of about 5 m is required, which makes it difficult to downsize the equipment.

  In addition, in the methods described in [Patent Document 2] and [Patent Document 3], the gas that has not been pressurized and dissolved in the pressurizing section after the pump out of the gas injected as coarse bubbles is a coarse bubble. It passes through the decompression nozzle as it is and flows into the contact tank mixed with the generated fine bubbles. As described above, millimeter-sized bubbles have a problem of low dissolution efficiency. Further, when coarse bubbles and fine bubbles come into contact with each other after passing through the pressure reducing nozzle, the fine bubbles may be combined with the coarse bubbles, and the content of fine bubbles having high dissolution efficiency may be reduced. In addition, even if this mixed water of fine bubbles and coarse bubbles is injected into a downflow contact tank that can increase the residence time in order to improve the ozone absorption efficiency, it is fine in the upward flow generated by coarse bubbles with a high ascent rate. Bubbles are entrained, and fine bubbles that reach the water surface may be diffused into the air.

  A first object of the present invention is to provide a liquid treatment method capable of improving the efficiency of water treatment such as disinfection, decolorization, deodorization, and turbidity improvement by recovering and reusing undissolved gas, and To provide an apparatus.

  A second object of the present invention is to provide an economical liquid processing apparatus by collecting and reusing undissolved gas, thereby improving gas utilization efficiency and reducing the amount of gas used.

  The third object of the present invention is to improve the efficiency of generating fine bubbles by collecting and reusing undissolved gas, and to reduce the amount of exhaust gas leaving the surface of the water to be treated in a coarse bubble state. Is to provide a simple liquid processing apparatus.

  The fourth object of the present invention is to recover and reuse undissolved gas to improve the fine bubble generation efficiency per pump power, reduce pump power and power consumption, and provide an economical liquid processing apparatus. It is to provide.

  In order to achieve the above object, the liquid processing apparatus of the present invention is a fine bubble generating system in which a gas is mixed in water, the mixed gas is pressure-dissolved with a pump, and the pressure is reduced to generate fine bubbles. The undissolved gas is recovered at the time of pressure dissolution, and the recovered gas is reused. Moreover, the contact tank which makes a fine bubble and to-be-processed water contact and reacts is provided, and water utilization is performed by improving the utilization efficiency of gas. For the generation of the fine bubbles, a pressurization, a shearing method, a swirling flow method, or the like may be used. You may measure the pressure of the water of the said pressure reduction nozzle, and may automatically control the frequency given to the motor of a pump so that this pressure may become fixed using an inverter.

  The decompression nozzle for generating fine bubbles is composed of a perforated plate having a plurality of holes or slits and a flow path limiting plate for changing the number of holes. To change the number of holes in the perforated plate, the flow restricting plate may be translated along the perforated plate, or the flow restricting plate may be rotated. Further, the perforated plate may be moved while fixing the flow path restriction plate.

  The number of holes in the perforated plate can be changed by measuring the flow rate of water mixed with the gas and dividing the mixed gas flow rate by the flow rate of water to obtain the apparent gas-liquid ratio flowing into the pump. The flow rate of water may be increased or decreased by changing the number of holes in the perforated plate so that the value is less than or equal to the allowable upper limit of the gas-liquid ratio of the pump.

  Further, a first gas mixer for mixing the gas in water and a second gas mixer for mixing the recovered gas are provided upstream of a pump for dissolving the gas under pressure. The gas mixer and the second gas mixer may be arranged in parallel to the flow path of water upstream of the pump, may be arranged in series, or may be mixed.

  The recovered gas is mixed with water to be treated or provided with a flow path for injecting it into the contact tank, and the flow path is provided with adjusting means for adjusting the flow rate of the recovered gas. These flow rates are provided with a retention container (buffer tank) for retaining the recovered gas, and a pressure reducing valve or a back pressure valve provided in the flow path between the retention container and the gas mixer or between the retention container and the contact tank. May be adjusted by maintaining the pressure in the residence container. Moreover, you may utilize the internal space of the flow path provided with the said pressure-reduction valve and a back pressure valve, without using a retention container for gas retention. In the contact tank, the recovery gas injection position may be a downstream tank that is not mixed with fine bubbles in order to prevent coalescence of bubbles, or a previous tank into which the water to be treated flows. When using ozone, in order to remove the ozone consumption substance in to-be-processed water previously, you may inject | pour collection | recovery gas in the upstream part of the injection | pouring position of water containing fine bubbles.

  The water for mixing the gas may be extracted from the contact tank, and the water in which the fine bubbles are generated may be returned to the contact tank and circulated. The water for mixing the gas may be supplied from the outside to generate the fine bubbles. Water may be passed directly through the contact tank. As the bubble type, a gas other than ozone may be used.

  ADVANTAGE OF THE INVENTION According to this invention, the water treatment performance and economical efficiency of the liquid processing apparatus which dissolves and utilizes gas can be improved. Further, since fine bubbles used for liquid treatment can be generated efficiently and stably, water treatment performance and flow stability can be improved.

  Embodiments 1 to 9 of the present invention will be described with reference to the drawings.

  A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a configuration diagram of a liquid processing apparatus according to a first embodiment, FIGS. 2 and 3 are cross-sectional views of a pressure reducing nozzle, a schematic diagram of a pipe viewed from the upstream side, and FIGS. 4 to 7 are explanatory diagrams regarding ozone utilization efficiency. .

  As shown in FIG. 1, the liquid processing apparatus of the present embodiment is connected to a flow path 13 provided at the bottom of a contact tank 5 described later, and a flow path 6 to which ozone gas 2 is supplied from an ozone generator (not shown). The gas mixer 7 that mixes the ozone gas introduced into the flow path 6 and the water 1 to be treated, and the gas mixer 50 that is connected to the gas mixer 7 and mixes the gas recovered by the gas-liquid separator 8 described later. And a pump 11 that is connected to the gas mixer 50 and feeds the water to be treated 1 mixed with the ozone gas 2 and the gas in the gas mixers 7 and 50, and a gas that is connected to the pump 11 and separates undissolved bubbles. A liquid separator 8; a pressure reducing nozzle 12 connected to the gas / liquid separator 8 to depressurize the water 1 to be treated; a contact tank 5 connected to the pressure reducing nozzle 11; and a bubble connected to the gas / liquid separator 8 and separated. Buffer tank 14 for retaining A back pressure valve 16 provided in the flow path 10 for connecting the contact tank 5 and 14, and a pressure reducing valve 15 provided in the flow path 9 for connecting the buffer tank 14 and the gas mixer 50. The pressure reducing valve 15 generally refers to a valve that exhausts while keeping the secondary pressure constant regardless of the primary pressure. The back pressure valve 16 is also called a relief valve, and refers to a valve that exhausts to the secondary side when the primary side pressure exceeds a threshold value or when the differential pressure between the primary side and the secondary side exceeds the threshold value.

  Here, the path composed of the flow path 13, the gas mixer 7, the gas mixer 50, the pump 11, and the pressure reducing nozzle 12 is referred to as a fine bubble generation system, and the gas-liquid separator 8, the buffer tank 14, and the flow path 9. A path constituted by the pressure reducing valve 15 is referred to as a gas recovery system. In the path constituted by the gas-liquid separator 8, the buffer tank 14, the flow path 10, and the back pressure valve 16, air is diffused into the contact tank 5.

  The water to be treated 3 is poured into the contact tank 5 and the treated water 4 is distributed. The inside of the contact tank 5 is partitioned by a partition plate, and has a structure that bypasses the plurality of tanks while the water to be treated is in contact with ozone. The contact tank 5 can be applied to a pool type, a U-shaped tube type, a concentric cylindrical type, and other water tank structures. The gas forming the fine bubbles is not limited to ozone gas, and air, carbon dioxide, and other gases can be used.

  In addition, as the extraction position of the flow path 13, an arbitrary position below the water surface of the contact tank 5 may be selected. Although not shown, it is preferable to measure the gas flow rate.

  The gas-liquid two-phase flow mixed with the ozone gas is pressurized by the pump 11, a part of the ozone gas is pressurized and dissolved, and the rest becomes coarse bubbles and flows into the gas-liquid separator 8. In the gas-liquid separator 8, coarse bubbles that have not been dissolved under pressure are separated upward by, for example, gravity separation, and the separated gas flows into the buffer tank 14.

  The water in which the ozone gas is dissolved under pressure is decompressed and foamed when passing through the decompression nozzle 12 to form ozone fine bubbles. The fine ozone bubbles flow into the contact tank 5 and cause water treatment such as disinfection, deodorization, and decolorization of the water to be treated 3. Here, the water in which the gas is mixed may be directly supplied to the contact tank 5 by supplying water from the outside and generating fine bubbles.

  On the other hand, the buffer tank 14 is connected to the gas mixer 50 provided on the suction side of the pump 11 via the pressure reducing valve 15 through the flow path 9, and all or part of the gas in the buffer tank 14 is a gas mixer. The ozone gas recovered in the buffer tank 14 is reinjected into the water to be treated. Here, the gas mixer 50 is a device that mixes gas with the water to be treated that flows through the flow path 13 in the same manner as the gas mixer 7. For example, the gas phase pipe is joined in a T shape to the pipe through which the water to be treated flows. The gas phase may be mixed from an air diffuser or a porous material, or an ejector may be used. The gas mixer 7 and the gas mixer 50 may be arranged in parallel in the flow path upstream of the pump 11 or may be arranged in series.

  The recovered gas can be reinjected by connecting the flow path 9 to the flow path 6 communicating with the gas mixer 7. On the other hand, the supply flow rate of the ozone gas 2 and the flow rate of the reinjection gas may vary due to the difference between the supply pressure of the ozone gas 2 in the flow path 6 and the pressure of the reinjection gas in the flow path 9. Therefore, as shown in the present embodiment, it is preferable to mix the gases independently with respect to the water to be treated flowing through the flow path 13.

  In the buffer tank 14, the flow path 10 is connected to the contact tank 5 via the back pressure valve 16, and the ozone gas exiting the back pressure valve 16 is diffused into the water to be treated in the contact tank 5. Although the diffused coarse bubbles have low dissolution efficiency, the water treatment action such as disinfection, deodorization, and decolorization of the water to be treated 3 occurs as in the case of the fine bubbles described above.

  The connection position of the flow path 10 to the contact tank 5 may be either upstream or downstream of the location where the fine bubbles are injected, and may diffuse into another tank partitioned by the partition plate in the contact tank 5. That is, in order to prevent coalescence of bubbles, a subsequent tank that is not mixed with fine bubbles may be used, or a previous tank into which the water to be treated flows may be used. When ozone is used, in order to remove ozone consumption substances in the water to be treated in advance, the recovered gas may be injected into the upstream portion of the injection position of the water containing fine bubbles. For the diffusion of air from the flow path 10 to the contact tank 5, the efficiency of dissolution in the water to be treated is improved by reducing the diameter of the diffused bubbles using a diffuser tube, a porous body or the like.

  When the bubbles are separated by the gas-liquid separator 8, since the bubbles intermittently flow into the gas-liquid separator 8, the pressure and flow rate of the separated gas vary. When this is directly flowed into the gas mixer 50, the gas-liquid ratio, which is the ratio of the gas to the water to be treated flowing through the flow path 13, fluctuates, causing the pump 11 to run idle and flow instability.

  Since the pressure reducing valve 15 is provided in the flow path 9 and the secondary pressure is constant in the pressure reducing valve 15, the ozone gas in the buffer tank 14 can be sent to the gas mixer 50 at a constant pressure. As a result, the gas flow rate flowing from the gas mixer 7 and the gas mixer 50 to the pump 11 becomes constant, and the flow of the water to be treated is stabilized without the pump 11 running idle due to the entrainment of gas. When the coarse bubbles separated by the gas-liquid separator 8 temporarily increase and the pressure in the buffer tank 14 becomes excessive, excess ozone gas is diffused into the contact tank 5 by the back pressure valve 16. The pressure in the buffer tank 14 is kept constant.

  As described above, since the gas recovery system is provided and reused, the gas recovered by the gas-liquid separator 8 can be sent to the gas mixer 50 at a constant flow rate to prevent fluctuations in the gas reinjection flow rate. As a result, the gas-liquid ratio in the gas mixer 7 can be maintained at a maximum value or a high range in which the pump 11 can be operated and high efficiency can be obtained.

  In order to maintain the gas-liquid ratio at the maximum value or high range where the pump 11 can be operated and high efficiency is obtained and to stably generate fine bubbles, the pressure on the upstream side of the decompression nozzle 12 is kept constant, It is effective to keep the gas-liquid ratio in an appropriate range. It is also effective to prevent the gas-liquid ratio from changing in the fine bubble generation state of the decompression nozzle 12, that is, the flow around the nozzle hole 62, which will be described later, with respect to fluctuations in the flow rate of the water to be treated.

  In the decompression nozzle 12 shown in FIG. 2, the nozzle portion is composed of a porous plate 60, and the flow path restriction plate 61 moves up and down by the rotation of the handle shaft 65, and the hole that opens out of the holes 62 provided in the porous plate 60 The number 62 can be changed manually. In this way, by adjusting the number of holes 62 opened in the perforated plate 60, the pressure and flow rate on the upstream side of the decompression nozzle 12 can be changed, and the fine bubbles corresponding to the set value of the flow rate of the ozone gas 2 can be changed. Can be operated at a low pressure and an appropriate flow rate.

  The pressure reducing nozzle 12 shown in FIG. 2 is an example in which the cross section of the edge portion of the flow path restriction plate 61 is formed perpendicular to the porous plate 60, but the edge portion 64 is connected to the porous plate 60 as shown in FIG. 3. May be formed at an acute angle. By forming the edge portion 64 at an acute angle with respect to the perforated plate 60, the disturbance of the water to be treated flowing from the vicinity of the edge portion 64 to the perforated plate 60 is reduced, and the vortex is generated and foamed on the upstream side of the perforated plate 60. The effect which prevents the fall of fine bubble production | generation efficiency can be anticipated.

  As shown in FIGS. 2 and 3, by adopting a nozzle that makes the number of holes 62 variable, the pressure loss of the nozzle portion can be adjusted without changing the hole diameter. And the flow rate is adjustable. This makes it possible to keep the diameter of the generated fine bubbles constant and to obtain a high dissolution efficiency. Moreover, the gas-liquid ratio in the gas mixer 7 can be maintained in a range where the pump 11 can be operated and high efficiency can be obtained. Further, when the pressure reducing nozzle 12 is clogged, the number of holes to be opened is increased, so that the clogged hole can be replaced with another hole, so that the flow rate of water to be treated that generates fine bubbles can be kept constant.

  To change the number of holes opened in the perforated plate, the flow restricting plate may be translated along the perforated plate, or the flow restricting plate may be rotated. Alternatively, the perforated plate may be moved while fixing the flow path limiting plate. In addition, for generating fine bubbles, a pressurization, a shearing method, a swirling flow method, or the like can be used.

  Next, the effect of the recovery of coarse bubbles by the gas-liquid separator 8 and the reinjection of the gas mixer 50 into the water to be treated will be described with reference to FIGS.

  FIG. 4 schematically shows a state where fine bubbles are generated in the decompression nozzle 12 when the gas-liquid separator 8 is not used. Water that has been pressure-dissolved with ozone gas by the pump 11 and coarse ozone bubbles that have not been pressure-dissolved pass through the vacuum nozzle 12. Since the fine bubbles are generated mainly by the reduced-pressure foaming action of water in which gas is dissolved under pressure, coarse bubbles do not become fine bubbles. Since the rising speed of the coarse bubbles is high, the bubbles rise faster than the fine bubbles immediately after flowing into the contact tank, and leave from the surface of the water to be treated to the upper gas phase space. For this reason, as shown in FIG. 6, the water treatment efficiency by ozone gas falls. In FIG. 6, the dissolved portion of the injected gas has a water treatment action, and the dissolution rate of coarse bubbles is assumed to be about 50% based on the knowledge obtained through experiments.

  On the other hand, FIG. 5 schematically shows a state where fine bubbles are generated at the decompression nozzle 12 when the gas-liquid separator 8 is used. The ozone gas dissolved under pressure in the pump 11 becomes fine bubbles when passing through the pressure reducing nozzle 12, and coarse ozone bubbles not dissolved under pressure are separated by the gas-liquid separator 8 and are supplied to the gas mixer 50. It is returned and reinjected into the water to be treated before pressurization on the upstream side of the pump 11. As a result, the ozone gas can be pressurized and dissolved at a high gas-liquid ratio in a range where the pump 11 does not run idle, and coarse bubbles can be prevented from flowing into the decompression nozzle 12. For this reason, as shown in FIG. 7, the amount of ozone gas desorbed from the water surface can be reduced, and the water treatment efficiency by ozone gas is improved. Here, the gas-liquid ratio is obtained as an apparent gas-liquid ratio of the two-phase flow that flows into the pump 11 by gradually reducing the gas flow to be mixed with the flow rate of water.

  When the ozone gas flow rate is reduced, the flow rate directly injected into the contact tank 5 is reduced. By reducing the flow rate of the ozone gas until the flow rate of the coarse bubbles becomes zero and setting the flow rate to an appropriate ozone gas flow, the generation efficiency of the fine bubbles can be increased to almost 100%. In this case, the flow rate of exhaust ozone gas desorbing from the water surface can be greatly reduced, and although not shown, the load on the exhaust ozone gas processing device in the upper space of the contact tank 5 can be reduced. In this case, the ozone injection rate of the water to be treated is adjusted by the generated ozone concentration.

  According to the present embodiment, it is possible to increase the generation ratio of fine bubbles and reduce the amount of exhaust ozone gas that separates from the water surface, so that the water treatment efficiency is improved and the amount of ozone used can be reduced. This has the effect of improving the economics of the liquid treatment apparatus and the effect of improving the water treatment performance.

  A second embodiment of the present invention will be described with reference to FIG. FIG. 8 is a configuration diagram of the liquid processing apparatus of this embodiment. In this embodiment, a pressure transmitter 51 for measuring pressure is installed in the fine bubble generating system of the liquid processing apparatus of Embodiment 1 on the downstream side of the pump 11 and on the upstream side of the pressure reducing nozzle 12. Are connected to the controller 52 and the inverter 53. The inverter 53 is connected to the pump 11 and controls the rotation speed of the pump 11.

  A target pressure is input to the controller 52, and the controller 52 performs, for example, PID control of the inverter 53 so that the upstream pressure of the pressure reducing nozzle 12 is kept constant at the target value. Thereby, the rotation speed of the pump 11 can be changed by the inverter 53, and the pressure upstream of the decompression nozzle 12 can be maintained at a constant set value.

  As a result, fluctuations in the pressure and flow rate of the pump 11 during the fine bubble generation process can be prevented, so that the diameter of the generated fine bubbles can be kept constant, and high dissolution efficiency can be obtained. In addition, since the pressure can be controlled to be a constant value, fluctuations in the gas-liquid flow rate can be prevented, the recovery flow rate of undissolved bubbles can be stabilized and maintained at a high value, and fine bubble generation efficiency per pump power can be improved. To do. Moreover, since fluctuations in pressure and flow rate can be prevented, the pressure of the pump 11 can be set low, and pump power and power consumption can be reduced.

  According to the present embodiment, it is possible to increase the generation ratio of fine bubbles and reduce the amount of exhaust ozone gas that separates from the water surface, so that the water treatment efficiency is improved and the amount of ozone used can be reduced. In addition, the pump pressure can be set low, and pump power and power consumption can be reduced. This has the effect of improving the water treatment performance and the effect of improving the economics of the liquid treatment apparatus.

  A third embodiment of the present invention will be described with reference to FIG. FIG. 9 is a configuration diagram of the liquid processing apparatus of this embodiment. In this embodiment, a liquid flow meter 54 is added to the flow channel 13 and a gas flow meter 55 is added to the flow channel 6 in the fine bubble generating system of the liquid processing apparatus of the second embodiment. Since the flow meter 54 measures the flow rate of the water extracted from the contact tank 5 and the flow meter 55 measures the flow rate of the ozone gas 2 supplied to the gas mixer 7, the gas-liquid ratio in the gas mixer 7 can be accurately measured. Can be calculated.

  As a result, the number of apertures of the decompression nozzle 12 can be adjusted so that the gas-liquid ratio is maintained at a maximum value or a high range where high efficiency can be obtained by the pump 11. Here, the gas / liquid ratio at which the pump 11 can obtain high efficiency is, for example, a large value of gas / liquid ratio in a range where the pump is idle or power consumption does not increase greatly. Since the gas-liquid ratio can be set appropriately, the flow rate of water to be treated pressurized by the pump 11 can be reduced with respect to the gas flow rate collected and re-injected by the gas mixer 50 in the same manner as the flow rate of the ozone gas 2. Pump power per generated amount can be reduced. In addition, when the pressure reducing nozzle 12 is clogged, the flow rate decreases at a constant pressure in the configuration shown in FIG. 9, so that the clogged state of the pressure reducing nozzle 12 can be grasped by monitoring the flow meter 54.

  According to the present embodiment, it becomes possible to set the flow rate of the pump low with a constant pressure, and pump power and power consumption can be reduced. Moreover, since the clogging of the decompression nozzle can be detected, there is an effect of improving the economic efficiency and reliability of the liquid processing apparatus.

  A fourth embodiment of the present invention will be described with reference to FIG. FIG. 10 is a configuration diagram of the liquid processing apparatus of this embodiment. In the present embodiment, a flow rate adjusting valve 66 is added to the fine bubble generating system of the liquid processing apparatus of the third embodiment, downstream of the pressure reducing valve 15 in the flow path 9 and upstream of the gas mixer 50.

  In the present embodiment, the flow rate of ozone gas reinjected from the gas mixer 50 into the water to be treated can be adjusted with high accuracy by the pressure reducing valve 15 and the flow rate adjusting valve 66. By using the pressure reducing valve 15 that can adjust the secondary pressure, the flow rate can be adjusted with high accuracy in a wider flow range.

  According to the present embodiment, it is possible to improve the setting accuracy of the ozone gas recovery and reinjection flow rate, so that the pump flow rate can be set low. As a result, pump power and power consumption can be reduced, which has the effect of improving the economics of the liquid processing apparatus.

  A fifth embodiment of the present invention will be described with reference to FIG. FIG. 11 is a configuration diagram of the liquid processing apparatus of this embodiment. In the present embodiment, the pressure reducing valve 15 is removed from the fine bubble generating system of the liquid processing apparatus shown in the fourth embodiment, and the buffer tank 14 includes a gas mixer 50 and a flow rate adjusting valve provided on the suction side of the pump 11. 66 is connected to the flow path 9 through 66, and all or part of the gas in the buffer tank 14 is returned to the gas mixer 50, and the ozone gas recovered in the buffer tank 14 can be reinjected into the water to be treated. It has become. In the buffer tank 14, the flow path 10 is connected to the contact tank 5 via the back pressure valve 16, and the ozone gas that has exited the back pressure valve 16 is diffused into the water to be treated in the contact tank 5, compared with the fine bubbles. Although the dissolution efficiency is low, water treatment effects such as disinfection, deodorization, and decolorization of the water to be treated 3 occur.

  On the other hand, the recovered ozone gas flows from the buffer tank 14 to the gas mixer 50 through the flow rate adjustment valve 66. Since the pressure reducing valve 15 is not used, ozone gas cannot be sent to the gas mixer 50 at a constant pressure. However, since the maximum pressure of the buffer tank 14 is limited by the back pressure valve 16, the flow rate flowing into the gas mixer 50 is The value is determined by the pressure limited by the back pressure valve 16. Thus, since there is a restriction | limiting in the gas flow volume which flows into the pump 11 from the gas mixer 7 and the gas mixer 50, the flow of to-be-processed water is stabilized, without the pump 11 running idle.

  According to the present embodiment, by replacing the expensive pressure reducing valve with a complicated structure with a flow rate adjusting valve, it is possible to prevent equipment failure and reduce the apparatus cost. Therefore, there is an effect of improving the reliability and economy of the liquid processing apparatus.

  A sixth embodiment of the present invention will be described with reference to FIG. FIG. 12 is a configuration diagram of the liquid processing apparatus of this embodiment. In the present embodiment, the fine bubble generating system of the liquid processing apparatus shown in the fourth embodiment includes the valve 57 in the flow path between the gas mixer 7 and the gas mixer 50, and the gas mixer 50 downstream of the valve 57. A coupled pressure gauge 58 is added upstream. Here, the coupled pressure gauge is a pressure gauge that can measure both positive and negative pressures.

  In the operation of the liquid processing apparatus of this embodiment, a standard value is set for the pressure measured by the compound pressure gauge 58, and the valve 57 is adjusted so that the indicated value of the compound pressure gauge 58 becomes the standard value. As a result, the pressure of the gas mixer 50 can be kept constant with respect to the secondary pressure of the pressure reducing valve 15 regardless of the operating state, so that the flow rate of ozone gas flowing through the gas mixer 50 can be kept constant. Therefore, the acceptable gas-liquid ratio of the pump 11 can be maintained, and the flow of the fine bubble generation loop is stabilized.

  According to the present embodiment, since the flow of the fine bubble generation loop is stabilized, the reliability of the liquid processing apparatus is improved.

  A seventh embodiment of the present invention will be described with reference to FIG. FIG. 13 is a configuration diagram of the liquid processing apparatus of this embodiment. This embodiment is configured in the same manner as the liquid treatment apparatus shown in FIG. 12, but is an example applied to other than the contact tank, and instead of flowing the treated water 1 from the contact tank 5, water supply 67 is performed. Water distribution 68 is performed.

  As shown in FIG. 13, a flow path for supplying gas 69, a flow path 13 for supplying water 67, a gas mixer 7, a gas mixer 50, a pump 11, and a pressure reducing nozzle 12, A gas recovery system composed of the gas-liquid separator 8, the buffer tank 14, the flow path 9 and the pressure reducing valve 15, and an exhaust system composed of the flow path 10 and the back pressure valve 16 are provided. Preferably, a pressure transmitter 51, a controller 52, and an inverter 53 for measuring the pressure upstream of the pressure reducing nozzle 12 are provided downstream of the pump 11, a flow meter 54 for liquid is provided in the flow path 13, and gas is provided in the flow path 6. The flow meter 55 is provided. A valve 57 is provided in the flow path between the gas mixer 7 and the gas mixer 50, and a coupled pressure gauge 58 is provided downstream of the valve 57 and upstream of the gas mixer 50.

  The water supply 67 supplied to the flow path 13 and the gas 69 supplied from a gas supply device (not shown) are mixed by the gas mixer 7 and flow through the flow path 13 as a gas-liquid two-phase flow. This gas-liquid two-phase flow is pressurized by the pump 11, and a part of the gas is pressurized and dissolved, and the rest becomes coarse bubbles and flows into the gas-liquid separator 8. In the gas-liquid separator 8, coarse bubbles that have not been dissolved under pressure are separated upward by, for example, the gas-liquid separator 8, and the separated gas flows into the buffer tank 14. The water in which the ozone gas is dissolved in the gas-liquid separator 8 is decompressed and foamed when passing through the decompression nozzle 12 to form fine bubbles. These fine bubbles become fine bubble water 68 together with the water supply 67 and are distributed.

  On the other hand, the buffer tank 14 is connected to the gas mixer 50 provided on the suction side of the pump 11 by the flow path 9 via the pressure reducing valve 15, and all or part of the gas in the buffer tank 14 is gas mixed. Returning to the vessel 50, the ozone gas recovered by the buffer tank 14 is reinjected into the water to be treated.

  A flow path 10 provided with a back pressure valve 16 is connected to the buffer tank 14, the end of the flow path 10 is open to the atmosphere, and the ozone gas exiting the back pressure valve 16 is released into the atmosphere. Here, when the gas 69 is harmful gas, the gas is decomposed without opening the flow path 10 to the atmosphere. When the gas 69 is a valuable gas, the gas is reused without opening the flow path 10 to the atmosphere.

  Since the pressure reducing valve 15 connected to the buffer tank 14 can send ozone gas to the gas mixer 50 at a constant pressure, the gas flow rate flowing from the gas mixer 7 and the gas mixer 50 to the pump 11 becomes constant, The flow of water to be treated is stabilized without the pump 11 running idle. When the coarse bubbles separated by the gas-liquid separator 8 temporarily increase and the pressure in the buffer tank 14 becomes excessive, excess gas is released into the atmosphere by the back pressure valve 16 and the buffer tank. The pressure of 14 is kept constant.

  Preferably, a pressure transmitter 51, a controller 52, and an inverter 53 for measuring the pressure upstream of the pressure reducing nozzle 12 are provided downstream of the pump 11. By inputting the target pressure to the controller 52, the inverter 53 is subjected to, for example, PID control according to a command from the controller 52 so that the pressure upstream of the pressure reducing nozzle 12 is kept constant at the target value, and the rotational speed of the pump 11 By changing the above, the pressure upstream of the pressure reducing nozzle 12 can be maintained at a constant set value.

  As a result, fluctuations in the pressure and flow rate of the pump 11 in the process of generating fine bubbles can be prevented, so that the diameter of the generated fine bubbles can be kept constant, and high dissolution efficiency can be obtained. In addition, since the pressure is constant, fluctuations in the gas-liquid flow rate when undissolved gas is recovered and reused are prevented, and the efficiency of generating fine bubbles per pump power is improved. Further, since fluctuations in pressure and flow rate can be prevented, the pressure of the pump 11 can be set low, and pump power and power consumption can be reduced.

  According to the present embodiment, since the generation ratio of fine bubbles can be increased, the amount of gas used can be reduced. In addition, the pump pressure can be set low, and pump power and power consumption can be reduced. This has the effect of improving the economics of the liquid processing apparatus.

  An eighth embodiment of the present invention will be described with reference to FIG. FIG. 14 is a configuration diagram of the liquid processing apparatus of this embodiment. In the present embodiment, the pressure reducing valve 15 is removed in the seventh embodiment, and the buffer tank 14 is connected to the flow path 9 via the gas mixer 50 provided on the suction side of the pump and the flow rate adjusting valve 66. All or part of the gas in the buffer tank 14 is returned to the gas mixer 50 so that the ozone gas recovered in the buffer tank 14 can be reinjected into the water supply 67. The flow path 10 is opened to the atmosphere from the buffer tank 14 via the back pressure valve 16, and the gas exiting the back pressure valve 16 is released into the atmosphere.

  On the other hand, the recovered gas flows from the buffer tank 14 to the gas mixer 50 through the flow rate adjustment valve 66. Since the pressure reducing valve 15 is not used, ozone gas cannot be sent to the gas mixer 50 at a constant pressure. However, since the maximum pressure of the buffer tank 14 is limited by the back pressure valve 16, the flow rate flowing into the gas mixer 50 is reduced. Has an upper limit determined by the back pressure valve 16. As a result, the gas flow rate flowing from the gas mixer 7 and the gas mixer 50 to the pump 11 is limited, and the flow of the water to be treated is stabilized without the pump 11 running idle.

  According to the present embodiment, by replacing the expensive pressure reducing valve with a complicated structure with a flow rate adjusting valve, it is possible to prevent equipment failure and reduce the apparatus cost. Therefore, there is an effect of improving the reliability and economy of the liquid processing apparatus.

  A ninth embodiment of the present invention will be described with reference to FIG. FIG. 15 is a configuration diagram of the liquid processing apparatus of this embodiment. In the present embodiment, a flow rate adjusting valve 70 is provided instead of the back pressure valve 16 in the seventh embodiment, and the buffer tank 14 includes a gas mixer 50, a pressure reducing valve 15 and a flow rate adjusting valve 66 provided on the suction side of the pump. And the gas in the buffer tank 14 is entirely or partially returned to the gas mixer 50 so that the ozone gas recovered in the buffer tank 14 can be reinjected into the water supply 67. Yes. The flow path 10 is opened to the atmosphere from the buffer tank 14 via the flow rate adjusting valve 70, and the gas exiting the flow path 10 is released into the atmosphere. The flow rate adjustment valve 70 is slightly opened.

  The gas in the buffer tank 14 is held by the flow rate adjusting valve 70 and the pressure reducing valve 15, and when the pressure in the buffer tank 14 increases, the amount of gas released from the flow rate adjusting valve 70 through the flow path 10 into the atmosphere is increased. To increase. On the other hand, the recovered gas flows from the buffer tank 14 to the gas mixer 50 through the pressure reducing valve 15 and the flow rate adjusting valve 66. In this embodiment, since the back pressure valve 16 is not used, the pressure in the buffer tank 14 cannot be kept constant, but the secondary pressure of the pressure reducing valve 15 is kept at a constant value by the function of the pressure reducing valve. If the pressure in the buffer tank 14 does not decrease, the flow rate flowing into the gas mixer 50 can be maintained at a constant value. As a result, the gas flow rate flowing from the gas mixer 7 and the gas mixer 50 to the pump 11 is kept constant, and the flow of the water to be treated is stabilized without the pump 11 running idle.

  According to the present embodiment, by replacing the back pressure valve having a complicated structure with a flow rate adjusting valve, it is possible to prevent equipment failure and reduce the apparatus cost. Therefore, there is an effect of improving the reliability and economy of the liquid processing apparatus.

1 is a configuration diagram of a liquid processing apparatus that is Embodiment 1 of the present invention. FIG. FIG. 3 is a schematic diagram illustrating a structure of a decompression nozzle according to the first embodiment. FIG. 3 is a schematic diagram illustrating a structure of a decompression nozzle according to the first embodiment. The figure explaining the ozone utilization efficiency of Example 1. FIG. The figure explaining the ozone utilization efficiency of Example 1. FIG. The figure explaining the ozone utilization efficiency of Example 1. FIG. Explanatory drawing regarding the ozone utilization efficiency of Example 1. FIG. The block diagram of the liquid processing apparatus which is Example 2 of this invention. The block diagram of the liquid processing apparatus which is Example 3 of this invention. The block diagram of the liquid processing apparatus which is Example 4 of this invention. The block diagram of the liquid processing apparatus which is Example 5 of this invention. The block diagram of the liquid processing apparatus which is Example 6 of this invention. The block diagram of the liquid processing apparatus which is Example 7 of this invention. The block diagram of the liquid processing apparatus which is Example 8 of this invention. The block diagram of the liquid processing apparatus which is Example 9 of this invention.

Explanation of symbols

1,3 Water to be treated 2 Ozone gas 4 Treated water 5 Contact tank 6, 9, 10, 13, 32, 40 Flow path 7, 50 Gas mixer 8 Gas-liquid separator 11 Pump 12 Pressure reducing nozzle 14 Buffer tank 15 Pressure reducing valve 16 Back pressure valve 21, 52 Controller 22, 54, 55 Flowmeter 23, 24, 25, 56, 66, 70 Flow regulating valve 30 Oxygen-enriched gas generator 31 Oxygen-enriched air 33 Ozone generator 41, 42 Injection position 43 Partition plate 51 Pressure transmitter 53 Inverter 57 Valve 58 Coupled pressure gauge 59 Handle 60 Perforated plate 61 Flow restricting plate 62 Hole 63 Pipe 64 Edge portion 65 Handle shaft 67 Water supply 68 Fine bubble water 69 Gas

Claims (15)

  A first gas mixer for mixing the supplied water and gas, a pump for pressurizing the gas-liquid two-phase flow mixed with the gas by the first gas mixer, and water pressurized by the pump A gas-liquid separator that collects undissolved gas, and a second gas-liquid mixer that is provided between the first gas mixer and the pump and is connected to the gas-liquid separator via a pressure reducing valve. And a decompression unit connected to the downstream side of the gas-liquid separator, and the water in which the undissolved gas is mixed by the second gas mixer is decompressed by the decompression unit and fine bubbles are formed in the water. A liquid processing apparatus characterized by foaming.   A first gas mixer for mixing the supplied water and gas, a pump for pressurizing the gas-liquid two-phase flow mixed with the gas by the first gas mixer, and water pressurized by the pump A gas-liquid separator that collects undissolved gas, and a second gas-liquid mixer that is provided between the first gas mixer and the pump and is connected to the gas-liquid separator via a pressure reducing valve. A flow path for discharging a part of the gas recovered by the gas-liquid separator via a back pressure valve connected to the gas-liquid separator, and a pressure reduction connected to the downstream side of the gas-liquid separator A liquid processing apparatus comprising: a means for reducing the pressure of the water in which the undissolved gas is mixed by the second gas mixer by the pressure-reducing means to foam fine bubbles in the water. A first gas mixer for mixing the supplied water and gas, a pump for pressurizing the gas-liquid two-phase flow mixed with the gas by the first gas mixer, and water pressurized by the pump A gas-liquid separator that collects undissolved gas, a second gas mixer provided on the suction side of the pump, and a gas recovered by the gas-liquid separator via the pressure reducing valve A flow path for returning to the mixer, and a contact tank that water-treats water to be treated with a part of the gas branched by the upstream side of the pressure reducing valve of the flow path and recovered by the gas-liquid separator via the back pressure valve or A second flow path that discharges into the atmosphere, and a decompression unit connected to the gas-liquid separator, and water in which the recovered undissolved gas is mixed is decompressed by the decompression unit and finely submerged in the water. A liquid processing apparatus for foaming bubbles.   A first gas mixer that mixes the supplied water and gas, a pump that pressurizes the gas-liquid two-phase flow mixed with the gas by the first gas mixer, and water pressurized by the pump A gas-liquid separator that collects undissolved gas, a buffer tank connected to the gas-liquid separator, a second gas mixer provided on the suction side of the pump, and the pressure in the buffer tank is reduced. A flow path for returning to the second gas mixer through a valve; and a decompression means connected to the gas-liquid separator, wherein the decompressed means removes water mixed with the recovered undissolved gas. A liquid processing apparatus characterized in that the fine bubbles are foamed in water by reducing pressure. A first gas mixer that mixes gas in water, a pump that pressurizes water mixed with gas by the first gas mixer, and gas that is not dissolved in water pressurized by the pump is recovered A gas-liquid separator, a buffer tank connected to the gas-liquid separator, a second gas mixer provided on the suction side of the pump, and a gas in the buffer tank to the second gas mixer A flow path for returning, a second flow path for releasing a part of the gas from the buffer tank through a back pressure valve into a contact tank for treating the water to be treated or into the atmosphere, and the gas-liquid separator. A liquid processing apparatus comprising: a decompression unit connected to the water, wherein the collected undissolved gas is depressurized by the decompression unit to foam fine bubbles in the water.   The liquid processing apparatus according to claim 5, wherein a pressure reducing valve is provided in a flow path for returning the gas in the buffer tank to the second gas mixer. The treated water be those contact tank for water treatment is provided, wherein the fine bubbles that are foamed in water under reduced pressure to carry out the reaction by contacting the water to be treated of the contact vessel by the pressure reducing means The liquid processing apparatus according to claim 1.   The water for mixing the gas is obtained by extracting the water to be treated in the contact tank, and has a flow path for flowing the extracted water to the gas mixer. A liquid processing apparatus according to 1.   An inverter for controlling the number of revolutions of the pump and a measuring means for measuring the pressure of the fluid are provided in a flow passage section downstream of the pump and upstream of the pressure reducing means, and the pressure measured by the measuring means is kept constant. The liquid processing apparatus according to claim 1, wherein the rotation speed of the pump is controlled by an inverter so as to be controlled.   The liquid processing apparatus according to claim 1, wherein the pressure reducing unit is a pressure reducing nozzle.   The liquid processing apparatus according to claim 10, wherein the decompression nozzle is a perforated plate provided with a plurality of holes or slits.   The pressure reducing means comprises a perforated plate having a plurality of holes or slits, and a flow path restriction plate for changing the number of holes or the area of the slits. The liquid processing apparatus as described.   The liquid processing apparatus according to claim 12, wherein an end surface of the flow path restriction plate is cut at an acute angle with respect to the surface of the porous plate.   10. The liquid processing apparatus according to claim 1, wherein at least one liquid phase flow meter is provided in a flow path section from an upstream side of the gas mixer to a downstream side of the decompression unit.   The liquid processing apparatus according to claim 1, wherein an ozone generator is connected to the gas mixer, and ozone gas is supplied as the gas.

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