JP6206204B2 - Backwash type filtration device and plate heat exchanger - Google Patents

Description

  The present invention relates to a backwashing type filtration apparatus provided with a deposit removing means for removing deposits such as biofilm and a plate heat exchanger provided with the deposit removing means.

  In recent years, water treatment technology that purifies water in a wide range of fields has been regarded as important. For example, ship ballast water management systems, water treatment systems for seawater temperature differential heat exchangers, hydropower stations, dams, and agricultural water Backwash type filtration devices are widely used in water treatment systems such as water intake systems, sewage treatment systems, factory drainage systems, seawater desalination / drinking water plant facilities, and the like.

  This backwash type filtration device includes, for example, a pressure vessel and a plurality of cylindrical filtration elements arranged in the pressure vessel, and flows raw water into the filtration element during the filtration operation, thereby filtering the element. The filtered water is generated by passing through the filtration channel formed in the filter, and the filtered water is flown back to the inside from the outside to the filtration element appropriately selected from the plurality of filtration elements. By carrying out sequentially, impurities such as microorganisms clogged in the filtration flow path are removed to enable continuous filtration (for example, Patent Document 1).

JP 2012-139635 A

  However, when the filtration operation as described above is continued, impurities such as microorganisms may adhere to and grow on the wall surface of the filtration element, causing dirt and slimming, and forming a biofilm or the like.

  These are very sticky, and once formed, it is difficult to remove them sufficiently by normal backwashing.Thus, despite the backwashing, the increased pressure loss is sufficiently reduced to reduce the flow rate. It could not be recovered, and there was a risk of reducing the raw water treatment capacity.

  As one of the methods for effectively removing such deposits, ozone (5 to 20 times that of hypochlorous acid) having excellent sterilization and cleaning effects is supplied to raw water and filtered water and dissolved. There is a method of removing deposits by supplying to the filtration element.

  However, the conventional technology is still not sufficient from the viewpoint of effectively supplying ozone and removing deposits efficiently, and supplies ozone more effectively to remove deposits more efficiently. There has been a demand for providing a deposit removal technique that can be removed.

The backwash type filtration apparatus according to claim 1 is:
A pressure vessel, one or a plurality of filtration elements that are disposed in the pressure vessel and filter raw water from the inside toward the outside, and are connected to one of the filtration elements, and filtered from the connected filtration element A backwashing type filtration device provided with a filtration unit comprising backwashing piping for backflowing water to wash the filtration element and switching means for switching the connection of the backwashing piping to the filtration element,
A deposit removing means for removing deposits formed on the filter element by supplying ozone to the filter element is provided,
A drainage mechanism for draining the water in the pressure vessel by the deposit removing means;
An ozone supply mechanism for supplying gaseous ozone into the drained pressure vessel;
An ozone circulation mechanism for forcibly circulating the supplied ozone to a circulation line formed via the filtration element and the backwash pipe in the pressure vessel. This is a washing filter.

The backwash type filtration apparatus according to claim 2 is:
2. The backwashing type filtration apparatus according to claim 1, wherein the ozone circulation mechanism is an ozone circulation mechanism that circulates the supplied ozone by causing the backwash pipe to flow backward.

The backwash type filtration device according to claim 3 is:
The backwash pipe is continuously connected to one filtration element for a predetermined time, and the rotation of the backwash pipe is controlled so that the supplied ozone is locally supplied to the predetermined filtration element. The backwashing filtration apparatus according to claim 1, further comprising a control unit.

The backwash type filtration device according to claim 4 is:
A pressure vessel, one or a plurality of filtration elements that are disposed in the pressure vessel and filter raw water from the inside toward the outside, and are connected to one of the filtration elements, and filtered from the connected filtration element A backwashing type filtration device provided with a filtration unit comprising backwashing piping for backflowing water to wash the filtration element and switching means for switching the connection of the backwashing piping to the filtration element,
A deposit removing means for removing deposits formed on the filter element by supplying ozone to the filter element is provided,
A fresh water replacement mechanism in which the deposit removing means replaces water in the pressure vessel with fresh water;
An ozone supply mechanism for supplying ozone to the fresh water in the replaced pressure vessel;
An ozone circulation mechanism for forcibly circulating the fresh water supplied with ozone to a circulation line formed via the filtration element and the backwash pipe in the pressure vessel; This is a backwash type filtration device.

The backwash type filtration apparatus according to claim 5 is:
The backwashing type filtration apparatus according to claim 4, wherein the ozone supply mechanism is an ozone supply mechanism that includes a microbubble nozzle and supplies microbubbles of ozone to the fresh water.

The backwash type filtration apparatus according to claim 6 is:
6. The backwashing type filtration apparatus according to claim 4 or 5, wherein the ozone circulation mechanism is an ozone circulation mechanism that circulates the fresh water supplied with ozone by causing the backwash pipe to flow backward. It is.

The backwash type filtration device according to claim 7 is:
The backwash pipe is continuously connected to one filtration element for a predetermined time, and the backwash pipe is rotated so that the fresh water supplied with ozone is locally supplied to the predetermined filtration element. The backwashing type filtration apparatus according to any one of claims 4 to 6, further comprising a control unit for controlling.

The backwash type filtration apparatus according to claim 8 is:
The backwash type filtration apparatus according to any one of claims 1 to 7, wherein the raw water is seawater.

  As a result of further investigation by the present inventor, such a deposit removing means is not only the above-described backwash type filtration device, but also a plate type that performs heat exchange between a low temperature fluid and a high temperature fluid via a heat exchange plate. It has been found that it is very useful even when used as a means for removing deposits from heat exchangers.

That is, the plate heat exchanger which is the first technology related to the present invention is:
A plate-type heat exchanger comprising at least one heat exchange unit in which a flow path for circulating a low-temperature fluid and a flow path for circulating a high-temperature fluid are alternately formed with each of a plurality of stacked heat exchange plates as a boundary. There,
A deposit removing means for removing deposits formed in the selected flow path by supplying ozone to at least one of the selected flow paths is provided,
A drainage mechanism for draining water in the flow path selected by the deposit removing means;
An ozone supply mechanism for supplying gaseous ozone into the drained flow path;
An ozone circulation mechanism for forcibly circulating the supplied ozone to a circulation line formed through the selected flow path.

And the plate type heat exchanger which is the 2nd technique relevant to the present invention is,
A plate-type heat exchanger comprising at least one heat exchange unit in which a flow path for circulating a low-temperature fluid and a flow path for circulating a high-temperature fluid are alternately formed with each of a plurality of stacked heat exchange plates as a boundary. There,
A deposit removing means for removing deposits formed in the selected flow path by supplying ozone to at least one of the selected flow paths is provided,
A fresh water replacement mechanism that replaces the medium in the selected flow path with fresh water by the deposit removing means;
An ozone supply mechanism for supplying ozone to the fresh water in the replaced flow path;
A plate heat exchanger comprising an ozone circulation mechanism for forcibly circulating the fresh water supplied with ozone to the circulation line formed through the selected flow path. is there.

Moreover, the plate type heat exchanger which is the third technology related to the present invention is:
The plate heat exchanger according to the second technique , wherein the ozone supply mechanism is an ozone supply mechanism that includes a microbubble nozzle and supplies ozone microbubbles to the fresh water.

  ADVANTAGE OF THE INVENTION According to this invention, the deposit removal technique which can supply ozone more effectively than before and can remove a deposit more efficiently can be provided.

It is a figure which shows the structure of the backwashing type | mold filtration apparatus which concerns on the 1st Embodiment of this invention. It is sectional drawing of the AA line shown in FIG. It is a figure which shows the structure of the backwashing type | mold filtration apparatus which concerns on the 2nd Embodiment of this invention. It is a figure which shows the whole structure of the plate type heat exchanger which concerns on the 3rd Embodiment of this invention. It is a figure which shows the structure of the plate type heat exchanger which concerns on the 3rd Embodiment of this invention. It is a figure which shows the time-dependent change of the flow volume in Example 1. FIG. It is a figure which shows the relationship between the differential pressure | voltage and flow volume in Example 1. FIG. It is a figure which shows the time-dependent change of the ozone concentration in Example 2. FIG.

1. First Embodiment In the present embodiment, gaseous ozone is supplied into a pressure vessel that has been drained and emptied, and gaseous ozone is forcibly circulated through a circulation line that passes through the pressure vessel and backwash piping. It is related with the backwashing type | mold filtration apparatus provided with the deposit | attachment removal means which removes the deposit | attachment formed in the filtration element by doing.

  Hereinafter, the backwashing type filtration apparatus according to the present embodiment will be specifically described with reference to the drawings.

  FIG. 1 is a diagram showing a configuration of a backwashing type filtration apparatus according to the present embodiment, and FIG. 2 is a cross-sectional view taken along line AA shown in FIG.

1-1. Device Configuration As shown in FIGS. 1 and 2, the backwash type filtration device according to the present embodiment includes a pressure vessel 2, and filtration is performed by passing raw water from the inside toward the outside, arranged in the pressure vessel 2. A plurality of filtration elements 6 and a backwash pipe that is connected to any one of the plurality of filtration elements 6 and backwashes the filtration elements 6 by flowing back the filtrate water from the outside to the inside of the connected filtration elements 6. There is provided a filtration unit 1 including a motor 21 as a switching means for switching the connection of the backwash pipe 21 to the plurality of filtration elements 6. In FIG. 1, 3 is an inlet for raw water, 4 is an outlet for filtered water, and an outlet 4 for filtered water is provided with a filtered water transfer pipe 15 for transferring the filtrate that has flowed out to the outside. .

  The inside of the pressure vessel 2 is partitioned into a raw water chamber 11 having an inflow port 3 and a filtered water chamber 12 having an outflow port 4 by a partition plate 5 having a plurality of openings 10.

  The plurality of filtration elements 6 are arranged circumferentially on the filtration water chamber 12 side of the partition plate 5 such that the plurality of openings 10 of the partition plate 5 and the bottom opening 14 of each of the filtration elements 6 overlap. Has been placed. Reference numeral 13 denotes a top plate of the filtration element 6.

  As the filtration element 6, a highly accurate (30 to 70 μm) filtration element of a piled disk (PD) system in which disk-type and ring-shaped filter media are stacked and fixed with bolts can be preferably used.

  The backwash pipe 21 is branched in the raw water chamber 11 of the pressure vessel 2, and backwash nozzles 20a and 20b are provided at the ends of the branch pipes 21a and 21b. Further, the backwash pipe 21 is connected to the motor 9 via the rotary shaft 22, and the backwash pipe 21 rotates as indicated by the arrow in FIG. The connection between the bottom opening 14 (opening 10 of the partition plate 5) and the backwash nozzles 20a and 20b of the backwash pipe 21 is sequentially switched.

  The above configuration is basically the same as that of the conventional backwash type filtration device. However, as described above, in the backwash type filtration device according to the present embodiment, ozone is further added to the filter element 6. Is provided with a deposit removing means for removing deposits formed on the filtration element 6.

  Specifically, as a deposit removing means, a drainage mechanism for draining the water in the pressure vessel 2, an ozone supply mechanism for supplying gaseous ozone into the drained pressure vessel 2, and the supplied ozone in the pressure vessel 2 is provided with an ozone circulation mechanism that forcibly circulates in a circulation line formed through the filtration element 6 and the backwash pipe 21.

  In the raw water chamber 11 of the pressure vessel 2, a drain pipe 23 is attached as a drainage mechanism for discharging the water in the pressure vessel 2, and by opening a drain valve 34 provided in the drain pipe 23, Water is discharged to the outside.

  And the backwashing type filtration apparatus which concerns on this Embodiment is equipped with the bypass path 41 which connects the filtrate water transfer pipe | tube 15 and the backwash piping 21 as shown in FIG. By opening the valves 35 and 36, a circulation line is formed through the filtration element 6, the filtrate transfer pipe 15, the bypass path 41, and the backwash pipe 21 in the pressure vessel 2.

  The bypass path 41 includes a blower 46 connected to an ozone supply device 44 serving as an ozone supply mechanism in the middle of the bypass path 41, and is circulated by operating the blower 46 while supplying gaseous ozone from the ozone supply device 44. Gaseous ozone is forcibly circulated in the line (see solid arrow in FIG. 1).

  Gaseous ozone has a longer half-life (about 120 minutes) and is superior in the ability to remove deposits compared to the case where ozone is supplied and dissolved in raw water or filtered water as in the prior art.

  On the other hand, since ozone in a gaseous state has a specific gravity greater than that of air, it tends to stay at the bottom of the pressure vessel 2. However, in the backwashing type filtration apparatus according to the present embodiment, as described above, the gaseous ozone is forced to circulate in the circulation line, so that the gaseous ozone does not stay at the bottom of the pressure vessel 2. Can be supplied to every corner. For this reason, the deposit | attachment formed in the filtration element can be removed efficiently, and the processing capacity of raw | natural water can be maintained in a high state.

1-2. Filtration operation and backwashing In the present embodiment, filtration and backwashing using a backwashing type filtration device are performed according to the following procedure.

  First, raw water is pumped by a pump (not shown) arranged upstream of the inlet 3 and flows into the raw water chamber 11 from the inlet 3.

  The raw water that has flowed into the raw water chamber 11 moves from the inside to the outside of the plurality of filtration elements 6, is filtered when passing through the filtration element 6, flows into the filtered water chamber 12 as filtered water, and then flows out. Flows out of 4.

  During the filtration operation, when impurities such as microorganisms adhere to the filtration flow path and the filtration element 6 is clogged, the pressure loss increases and the raw water treatment capacity decreases. Therefore, in parallel with the filtration operation, only the filtration element 6 connected to the backwash pipe 21 is subjected to backwashing in which filtered water flows backward from the outside to the inside, so that the filtration operation is performed with the other filtration elements 6. Remove clogging while continuing. Thereby, the processing capacity of raw water can be recovered without stopping the filtration operation, and continuous filtration becomes possible.

  Specifically, by opening the backwash pipe ball valve 33, the backwash pipe 21 opened to the outside is rotated by the movement of the motor 9, and the backwash nozzles 20a and 20b are moved to the plurality of filtration elements 6, respectively. Are connected in sequence.

  In the filtration element 6 to which the backwash nozzles 20a and 20b are connected, the filtered water flows backward from the outside to the inside due to the pressure difference with the outside, so that the impurities clogged in the filtration flow path of the filtration element 6 are removed. Then, it is discharged outside through the backwash pipe 21.

1-3. However, as described above, impurities such as microorganisms adhering to the wall surface of the filtration element may form a deposit such as a biofilm. These deposits are very sticky, and once formed, it is difficult to remove them sufficiently by normal backwashing, so that the treatment capacity of raw water can be restored despite backwashing. become unable.

  Therefore, for example, when the pressure loss between the inlet 3 and the outlet 4 and the flow rate of the filtrate are continuously monitored and it is detected that the pressure loss has increased or the flow rate has decreased, the filtration operation is temporarily stopped and the filtration element 6 is stopped. Start removing the deposits. Moreover, you may remove a deposit | attachment at the time of regular maintenance.

  Specifically, first, the water in the pressure vessel 2 is discharged by closing the butterfly valves 31 and 32 disposed in the filtered water transfer pipe 15 upstream of the inflow port 3 and opening the drain valve 34.

  After the pressure vessel 2 is emptied, the drain valve 34 and the backwash pipe ball valve 33 of the backwash pipe 21 are closed, and the motorized valves 35 and 36 on the bypass path 41 are opened. Thereby, a circulation line is formed in the pressure vessel 2 through the filtration element 6, the filtrate water transfer pipe 15, the bypass path 41, and the backwash pipe 21.

  Next, gaseous ozone is supplied from the ozone supply device 44 and the blower 46 is operated. Thereby, gaseous ozone can be forcedly circulated through the formed circulation line. Specifically, the gaseous ozone is forcibly sent to the circulation line by forcibly sending the gaseous ozone in the direction in which the backwash pipe 21 flows backward by the operation of the blower 46 (the direction of the solid line arrow in FIG. 1). Circulate.

  At this time, the motor 9 is appropriately operated by a control unit (not shown) that controls the motor 9 as the switching means, so that the backwash nozzles 20a and 20b are connected to one filtration element 6 for a predetermined time. It is preferable to control the rotation of the backwash pipe 21. As a result, the ozone that has flowed back through the backwash pipe 21 is locally supplied to the inside of the predetermined filtration element 6, and the ability to remove deposits due to ozone can be more appropriately exhibited. Deposits adhered to the element 6 can be removed.

  The ozone supplied to the inside of the filtration element 6 continues to flow back to the filtered water chamber 12 and flows out to the filtered water transfer pipe 15 through the outlet 4. The ozone that has flowed out is then taken into the bypass passage 41, flows back through the backwash pipe 21 again, and is supplied to the inside of the filtration element 6.

  As described above, the forced circulation of gaseous ozone is repeated, so that the half-life is long and the deposit removing ability is excellent, but the specific gravity is larger than air and tends to stay at the bottom of the pressure vessel 2. Since the gaseous ozone which it has can be appropriately supplied inside the filtration element 6, the deposit | attachment adhering to the filtration element can fully be removed.

  In addition, by repeating the circulation of gaseous ozone, it is possible to reuse ozone that did not react with deposits in a single cycle, thus sufficiently suppressing the increase in cost associated with the deposit removal process, Deposits adhering to the filter element can be sufficiently removed.

  And since gaseous ozone is regulated by the ILO (International Labor Organization) etc. to be discharged into the atmosphere as it is, decomposition treatment after use is required, but according to this embodiment, By supplying a sufficiently high concentration of ozone in advance and continuing the circulation, the ozone concentration after removal of the deposits can be sufficiently reduced to a level that allows exhaustion. Occurrence can be reduced.

  Moreover, in this Embodiment, since the gaseous ozone is circulated by making the backwash piping 21 flow backward so that gaseous ozone passes toward the outer side from the inner side of the filtration element 6, a deposit | attachment is formed. Ozone can be effectively supplied to the inside of the filter element 6 that is easily subjected to, and deposits can be more efficiently removed.

  Moreover, when filtering seawater, if ozone is supplied to the raw water or filtered water before filtration, ozone is halved in a very short time of about 5.8 seconds due to reaction with bromine in the seawater. The backwashing type filtration apparatus according to the present embodiment circulates gaseous ozone in the circulation line after emptying the pressure vessel 2, so that it is difficult to remove deposits by seawater in the past. It can be preferably used for a mold filtration device.

2. Second Embodiment In this embodiment, after the water in the pressure vessel is replaced with fresh water, ozone is supplied to the substituted fresh water to dissolve it, and the fresh water in which ozone is dissolved is supplied to the pressure vessel and the backwash pipe. The present invention relates to a backwashing type filtration apparatus provided with a deposit removal means for removing deposits formed on a filtration element by forcibly circulating it through a circulation line.

  Hereinafter, the backwashing type filtration apparatus according to the present embodiment will be specifically described with reference to the drawings.

  FIG. 3 is a diagram showing a configuration of the backwashing type filtration apparatus of the present embodiment.

2-1. Apparatus Configuration As shown in FIG. 3, the backwashing type filtration apparatus according to the present embodiment includes a fresh water replacement mechanism 47 that replaces the water in the pressure vessel 2 with fresh water as the deposit removing means, and the replaced pressure vessel. Ozone supply mechanism 45 for supplying ozone to fresh water in 2 and ozone forcibly circulating the fresh water supplied with ozone to a circulation line formed through a filtration element and a backwash pipe in the pressure vessel. The second embodiment is different from the first embodiment in that a circulation mechanism is provided.

  The fresh water replacement mechanism 47 is connected to the filtered water transfer pipe 15, and supplies the fresh water into the pressure vessel 2 from the outlet 4 via the filtered water transfer pipe 15, so that the water in the pressure vessel 2 is purified. Replace with.

  Also in the present embodiment, the filtered water transfer pipe 15 and the backwash pipe 21 are connected by the bypass path 41, and the motorized valves 35 and 36 are opened, whereby the filtration element 6 in the pressure vessel 2, the filtration A circulation line passing through the water transfer pipe 15, the bypass path 41, and the backwash pipe 21 is formed.

  An ozone supply mechanism 45 is provided in the middle of the bypass path 41, and the ozone supply mechanism 45 includes an ozone supply device 44 and a microbubble nozzle 43.

  In addition, a pump 42 is provided on the bypass path 41, and when the pump 42 is operated, fresh water supplied with ozone is forcibly circulated in a circulation line formed by the bypass path 41 ( (See solid arrow in FIG. 3).

  When the ozone supply device 44 is operated and ozone is supplied to the fresh water in the bypass passage 41, the supplied ozone is dissolved in the fresh water. When ozone is dissolved in fresh water, the half-life can be extended (about 30 minutes) compared to the case where it is dissolved in raw water or filtered water as in the past, and excellent deposit removal capability is demonstrated. Can do. Furthermore, in the present embodiment, ozone in a state dissolved in water is circulated, so that it can be sufficiently supplied to every corner of the container without being retained in a specific part. As a result, the deposits formed on the filtration element can be efficiently removed and the raw water treatment capacity can be maintained at a high level.

2-2. Filtration operation and backwashing Since the filtration operation and backwashing using the backwashing type filtration apparatus according to the present embodiment are performed in the same manner as in the first embodiment, description thereof will be omitted.

2-3. Removal of deposits When removing deposits using the backwashing type filtration apparatus according to the present embodiment, first the drain valve 34 is opened and the pressure vessel is opened from the drain tube 23 as in the first embodiment. Drain the water in 2.

  After the pressure vessel 2 is emptied, the clean water is supplied into the pressure vessel 2 by closing the drain valve 34 and the backwash piping ball valve 33 of the backwash piping 21 and operating the fresh water replacement mechanism 47. . Thereby, the water in the pressure vessel 2 is replaced with fresh water.

  Thereafter, the motor-operated valves 35 and 36 on the bypass path 41 are opened. Thereby, similarly to the first embodiment, a circulation line is formed in the pressure vessel 2 via the filtration element 6, the filtrate water transfer pipe 15, the bypass path 41, and the backwash pipe 21.

  Next, the pump 42 on the bypass path 41 is operated, and fresh water is taken into the bypass path 41 from the filtered water transfer pipe 15 as indicated by a solid arrow in FIG.

  Then, ozone is supplied from the ozone supply device 44 to the fresh water taken into the bypass passage 41 via the microbubble nozzle 43. The supplied ozone is sent to the backwash pipe 21 in a state dissolved in fresh water, and the backwash pipe 21 is forced to flow back and circulate through the circulation line. Thereby, it sends out to the filtrate water chamber 12 of the pressure vessel 2 via the filtration element 6 to which the backwash nozzles 20a and 20b are connected.

  After being sent to the filtered water chamber 12 of the pressure vessel 2, as in the first embodiment, it flows out to the filtered water transfer pipe 15 through the outlet 4 and is taken into the bypass path 41 again and backwashed. It is supplied to the filtration element 6 to which the nozzles 20a and 20b are connected.

  Thus, by using ozone in a state dissolved in fresh water, it is possible to supply ozone in a state where the half-life is longer than that in the past and the deposit removing ability is excellent to the filtration element. Moreover, by repeating the forced circulation of the fresh water in which ozone is dissolved, the fresh water in which ozone is dissolved can be easily and sufficiently supplied to every corner of the container. As a result, the deposits attached to the filtration element can be sufficiently removed.

  Moreover, in the backwashing type filtration apparatus of this Embodiment, since the inside of the pressure vessel 2 is filled with fresh water, the above deposit removal process and backwashing can be performed alternately. Thereby, the deposit | attachment of the filtration element 6 can be removed more effectively.

  Moreover, in this Embodiment, ozone is made into the state of a microbubble and is supplied to fresh water. Since these microbubbles can enter the inside of the deposit, supplying ozone microbubbles to the filtration element further improves the sterilization / cleaning effect of ozone and more easily removes the deposit from the filtration element. be able to.

  In the backwashing type filtration device of the present embodiment described above, the fresh water is supplied after the pressure vessel 2 is emptied, but the pressure is reduced by simultaneously performing the drainage of the pressure vessel and the supply of fresh water. The water in the container 2 may be replaced with fresh water.

  In addition, it is preferable that it is about 1.0-10.0 ppm as a density | concentration of the ozone supplied to fresh water. In this way, by supplying ozone in an appropriate range of concentration to the filtration element, the deposits can be removed more efficiently.

  Furthermore, when supplying ozone, it is preferable to provide an ozone concentration measuring device in the filtrate transfer pipe 15 and adjust the ozone supply amount appropriately based on the measurement result because the ozone supply amount can be reduced.

3. Third Embodiment In this embodiment, after draining the flow path of a heat exchange plate through which a low-temperature fluid or a high-temperature fluid circulates, gaseous ozone is supplied into the empty flow path, and the flow path passes through the flow path. The present invention relates to a plate heat exchanger provided with a deposit removing means for removing deposits formed in a flow path of a heat exchange plate by forcibly circulating gaseous ozone in a circulating line.

  Hereinafter, the plate heat exchanger according to the present embodiment will be specifically described with reference to the drawings.

3-1. Apparatus Configuration The plate heat exchanger includes at least one heat exchange unit in which a flow path for circulating a low-temperature fluid and a flow path for circulating a high-temperature fluid are alternately formed with each of a plurality of stacked heat exchange plates as a boundary. The low-temperature fluid and the high-temperature fluid exchange heat with each other by circulating the low-temperature fluid and the high-temperature fluid through the flow path formed between the heat exchange plates.

  FIG. 4 is a schematic diagram illustrating the configuration of the piping of the plate heat exchanger according to the present embodiment. As shown in FIG. 4, the plate heat exchanger according to the present embodiment includes a plurality of heat exchange units 100, and a low-temperature fluid supply pipe for supplying a low-temperature fluid to each heat exchange unit 100. 130 and a cryogenic fluid discharge pipe 140 for discharging the cryogenic fluid are connected. The heat exchange unit 100 is also connected with a high-temperature fluid supply pipe 120 for supplying a high-temperature fluid and a high-temperature fluid discharge pipe 150 for discharging the high-temperature fluid.

  FIG. 5 is an exploded perspective view of the heat exchange unit 100 in FIG. As shown in FIG. 5, the heat exchange unit 100 is fixed in a state where the first heat exchange plate 101a and the second heat exchange plate 101b having a quadrangular shape, more specifically, a rectangular shape are alternately stacked in a vertical posture. It is configured by being sandwiched between frames 102.

  Gaskets (not shown) are attached to the outer peripheral edges of the heat exchange plates 101a and 101b, and the low-temperature channel 107 and the high-temperature channel 108 are separated from each other by the stacked heat exchange plates 101a and 101b. And are formed alternately.

  The low-temperature channel 107 is a channel for circulating a low-temperature fluid, and is connected to the low-temperature fluid supply pipe 130 via the low-temperature fluid inlet 105 and to the low-temperature fluid discharge pipe 140 via the low-temperature fluid outlet 103. Are connected (see FIG. 4).

  On the other hand, the high-temperature channel 108 is a channel for circulating a high-temperature fluid, and is connected to the high-temperature fluid supply pipe 120 via the high-temperature fluid inlet 104 and is also connected to the high-temperature fluid outlet pipe via the high-temperature fluid outlet 106. 150 (see FIG. 4).

3-2. Heat Exchange In the present embodiment, the heat exchange of the fluid using the plate heat exchanger is performed according to the following procedure. First, a low-temperature fluid is supplied from a low-temperature fluid supply pipe 130 to each heat exchange unit 100 and a high-temperature fluid is supplied from a high-temperature fluid supply pipe 120 to each heat exchange unit 100 by a pressure pump (not shown) arranged upstream of each supply pipe. Is done.

  The low-temperature fluid that has flowed into the heat exchange unit 100 flows in the low-temperature flow path 107 for the low-temperature fluid, and the high-temperature fluid flows in the high-temperature flow path 108 for the high-temperature fluid (see FIG. 4). At this time, heat exchange is performed between the low-temperature fluid and the high-temperature fluid through the heat exchange plates 101a and 101b, so that the temperatures of the respective fluids are close to each other, that is, the low-temperature fluid is heated and the high-temperature fluid is heated The fluid is cooled.

  The low-temperature fluid that has undergone heat exchange in the heat exchange unit 100 is discharged from the low-temperature fluid discharge pipe 140 through the low-temperature fluid outlet 103, and the high-temperature fluid is discharged from the high-temperature fluid discharge pipe 150 through the high-temperature fluid outlet 106. Is done.

3-3. However, when impurities are contained in a low-temperature fluid or a high-temperature fluid, the impurities attached to the surface of the heat exchange plate form a deposit such as a biofilm, thereby reducing the heat transmissivity. As a result, the efficiency of heat exchange via the heat exchange plate may be reduced.

  In addition, these deposits are very sticky, and once formed, it is difficult to remove them sufficiently. Therefore, it is necessary to disassemble and clean the heat exchange unit, resulting in a decrease in operating efficiency.

  The plate heat exchanger according to the present embodiment is selected by supplying ozone to at least one selected flow path in addition to the same configuration as the conventional plate heat exchanger. A deposit removal means for removing deposits formed in the flow path is provided. In the following, the deposit removal means for removing deposits formed on the surface of the heat exchange plate on the low temperature channel side will be described.

  Specifically, the deposit removing means includes a drainage mechanism for draining water in the low temperature channel 107, an ozone supply mechanism for supplying gaseous ozone into the drained low temperature channel 107, and at least a heat exchange unit. And an ozone circulation mechanism that forcibly circulates ozone supplied to a circulation line formed via 100 low-temperature flow paths 107.

  A drain pipe 142 is attached to the low-temperature fluid discharge pipe 140 as a drainage mechanism for discharging water in the low-temperature flow path 107. By opening a drain valve 143 provided in the drain pipe 142, Water is discharged to the outside.

  The plate heat exchanger according to the present embodiment includes a bypass path 110 that connects the low-temperature fluid supply pipe 130 and the low-temperature fluid discharge pipe 140, and the motor-operated valve 113 on the bypass path 110 is opened. A circulation line passing through the low-temperature flow path 107, the low-temperature fluid discharge pipe 140, the bypass path 110, and the low-temperature fluid supply pipe 130 of the heat exchange unit 100 is formed.

  The bypass path 110 includes a blower 111 to which an ozone supply device 112 serving as an ozone supply mechanism is connected in the middle of the bypass path 110, and is circulated by operating the blower 111 while supplying gaseous ozone from the ozone supply device 112. Ozone is forced to circulate through the line.

  In the present embodiment, as in the case of the backwash type filtration apparatus according to the first embodiment, the ozone in the gaseous state has a longer half-life than when dissolved in raw water or filtered water as in the prior art. By supplying this, it is possible to exhibit excellent sterilization / cleaning ability and efficiently remove deposits.

  In addition, by forcibly circulating the gaseous ozone, the gaseous ozone can be sufficiently supplied to every corner without staying in a specific part, so that it is formed in the flow path of the heat exchange plate. Deposits can be removed more efficiently.

3-4. In the plate heat exchanger according to the present embodiment, the temperature difference between the low temperature fluid supply pipe 130 and the low temperature fluid discharge pipe 140 (or between the high temperature fluid supply pipe 120 and the high temperature fluid discharge pipe 150). The temperature difference) is continuously monitored, and when it is detected that the heat transmissivity has been reduced, the heat exchange operation is temporarily stopped and the removal of the deposits is started. Moreover, you may remove a deposit | attachment at the time of regular maintenance.

  Specifically, first, the butterfly valves 131 and 141 arranged in the cryogenic fluid supply pipe 130 and the cryogenic fluid discharge pipe 140 are closed, and the drain valve 143 is opened to drain the water in the cryogenic flow path 107.

  After the inside of the low temperature channel 107 becomes empty, the drain valve 143 is closed and the motor operated valve 113 on the bypass path 110 is opened. As a result, a circulation line is formed in the heat exchange unit 100 via the low temperature passage 107, the low temperature fluid discharge pipe 140, the bypass path 110, and the low temperature fluid supply pipe 130.

  Next, gaseous ozone is supplied from the ozone supply device 112 to the bypass path 110 and the blower 111 is operated. Thereby, ozone can be forcedly circulated through the formed circulation line. Specifically, gaseous ozone supplied to the low-temperature fluid supply pipe 130 via the bypass path 110 is supplied to the low-temperature flow path 107 in the heat exchange unit 100.

  The ozone supplied to the low-temperature channel 107 is discharged to the low-temperature fluid discharge pipe 140 through the low-temperature fluid outlet 103, and then taken into the bypass path 110 and transferred again to the low-temperature fluid supply pipe 130, and each heat exchange plate. It is supplied to the low-temperature channel 107 between 101a and 101b.

  Thus, by repeating the forced circulation of gaseous ozone, while having a long half-life and excellent deposit removal capability, gaseous ozone having a characteristic that the specific gravity is larger than air, Since it can supply appropriately to the flow path between heat exchange plates, the deposit | attachment adhering to the surface of a heat exchange plate can fully be removed.

  In addition, by repeating the circulation of gaseous ozone, it is possible to reuse ozone that did not react with the deposits in a single cycle, thus sufficiently suppressing the increase in cost associated with the deposit removal process, Adhering matter adhering to the surface of the heat exchange plate can be sufficiently removed.

  And since the circulation line using the bypass path 110 is formed and gaseous ozone is forcibly circulated using the blower 111, the specific gravity that is larger than the air and that tends to stay is sufficiently supplied to every corner. And ozone can be effectively supplied to the low temperature flow path.

  In the above embodiment, for convenience of explanation, the case where gaseous ozone is supplied and circulated through the low temperature flow path has been described. However, when deposits are easily formed on the surface of the heat exchange plate on the high temperature flow path side. It is preferable to form a circulation line that passes through the high-temperature flow path of the heat exchange unit and circulate ozone through this circulation line.

  In addition, as in the case of the backwash type filtration device according to the second embodiment, even when fresh water in which ozone is dissolved is circulated instead of gaseous ozone, the deposits adhered to the surface of the heat exchange plate Can be sufficiently removed.

  Here, in order to circulate the fresh water in which ozone is dissolved in the circulation line passing through the flow path of the heat exchange unit, for example, the fresh water in which the medium in the flow path is replaced with the fresh water on the bypass path 110 in FIG. It is preferable to provide a replacement mechanism and to provide a pump for forcibly feeding fresh water instead of the blower 111. At this time, it is more preferable to attach a microbubble nozzle to the ozone supply device 112 and supply ozone in a microbubble state to fresh water.

  Hereinafter, the present invention will be described more specifically with reference to examples.

Example 1
Seawater filtration and backwashing were continuously carried out using the backwashing type filtration apparatus having the configuration shown in FIG. 1, and the average flow rate (Average Qr) and the maximum flow rate (MAX Qr) were measured every day. The measurement results are shown in FIG. On the 31st day, measurement was not performed due to a power failure.

  From FIG. 6, both the average flow rate and the maximum flow rate gradually decreased with the passage of days, and the maximum flow rate greatly decreased on the 37th day. This is because deposits were formed inside the filtration element 6 as the filtration operation continued, and the deposits could not be removed properly by backwashing. It is thought that was stuck.

  Therefore, in order to remove such deposits, on the 40th day, the water in the pressure vessel 2 is drained to form a circulation line passing through the filtration element 6 and the backwash pipe 21, and gaseous ozone Was supplied to a 5000 ppm circulation line, and the deposits were removed by circulation for 30 minutes.

As a result, the average flow rate and the maximum flow rate after the 40th day recovered, and on the 41st day, the maximum flow rate exceeded 40 m ³ / hr. From this, by draining the water in the pressure vessel and forcibly circulating ozone in a gaseous state, gas ozone with a long half-life is appropriately supplied to the filtration element to efficiently remove deposits. I was able to confirm.

  In addition, the flow in the pressure vessel 2 is started at the start of the filtration operation (day 0), when the filtration element is clogged with the deposit (day 39), and after the deposit is removed (day 63). The differential pressure (ΔP (MPa)) between the inlet 3 and the outlet 4 was measured. FIG. 7 shows the relationship between the measurement result of the differential pressure and the measurement result of the instantaneous flow rate.

  From FIG. 7, it was possible to secure a large flow rate with a low differential pressure on the 0th day of the filtration operation start, but on the 39th day when the filtration element was clogged, the differential pressure increased and the flow rate decreased. . However, it was confirmed that by performing the removal process of the deposits, the deposits were appropriately removed and the differential pressure and flow rate could be recovered to a state close to the start of the filtration operation.

(Example 2)
In the backwashing type filtration apparatus having the configuration shown in FIG. 1, deposits were formed on the filter element by continuously performing the backwashing filtration operation for 39 days. Next, the water in the pressure vessel is drained, and then 5000 ppm of gaseous ozone is supplied into the pressure vessel over 30 minutes, and ozone is forcibly circulated for 70 minutes from the start of supply to remove deposits. went. FIG. 8 shows the measurement results of ozone concentration and the transition (theoretical value) of the ozone supply amount in the deposit removal process.

  As shown in FIG. 8, the ozone concentration after the removal treatment of the adhering matter is lower than the concentration at the time of supply, and after the supply of ozone is stopped, the ozone concentration is decreased with the passage of time. It can be seen that the deposits are appropriately removed by the reaction.

  As mentioned above, although this invention was demonstrated based on embodiment, this invention is not limited to said embodiment. Various modifications can be made to the above-described embodiment within the same and equivalent scope as the present invention.

DESCRIPTION OF SYMBOLS 1 Filtration unit 2 Pressure vessel 3 Inlet 4 Outlet 5 Partition plate 6 Filtration element 9 Motor 10 Opening part 11 Raw water chamber 12 Filtration water chamber 13 Top plate 14 Bottom opening 15 Filtrated water transfer pipe 20a, 20b Backwash nozzle 21 Reverse Washing pipes 21a, 21b Branch pipes 22 Rotating shafts 23, 142 Drain pipes 31, 32, 131, 141 Butterfly valve 33 Backwash pipe ball valves 34, 143 Drain valves 35, 36, 113 Motorized valves 41, 110 Bypass path 42 Pump 43 Microbubble nozzles 44, 112 Ozone supply device 45 Ozone supply mechanism 46, 111 Blower 47 Fresh water replacement mechanism 100 Heat exchange unit 101a First heat exchange plate 101b Second heat exchange plate 102 Fixed frame 103 Low temperature fluid outlet 104 High temperature fluid inlet 105 Low temperature Fluid inlet 106 Hot fluid outlet 107 Temperature flow path 108 hot flow path 120 hot fluid supply pipe 130 cryogen supply tube 140 cryogen discharge pipe 150 hot fluid discharge pipe

Claims (8)

A pressure vessel, one or a plurality of filtration elements that are disposed in the pressure vessel and filter raw water from the inside toward the outside, and are connected to one of the filtration elements, and filtered from the connected filtration element A backwashing type filtration device provided with a filtration unit comprising backwashing piping for backflowing water to wash the filtration element and switching means for switching the connection of the backwashing piping to the filtration element,
A deposit removing means for removing deposits formed on the filter element by supplying ozone to the filter element is provided,
A drainage mechanism for draining the water in the pressure vessel by the deposit removing means;
An ozone supply mechanism for supplying gaseous ozone into the drained pressure vessel;
An ozone circulation mechanism for forcibly circulating the supplied ozone to a circulation line formed via the filtration element and the backwash pipe in the pressure vessel. Washing filtration device.   The backwashing type filtration apparatus according to claim 1, wherein the ozone circulation mechanism is an ozone circulation mechanism that circulates the supplied ozone by causing the backwash pipe to flow backward.   The backwash pipe is continuously connected to one filtration element for a predetermined time, and the rotation of the backwash pipe is controlled so that the supplied ozone is locally supplied to the predetermined filtration element. The backwashing type filtration apparatus according to claim 1, further comprising a control unit. A pressure vessel, one or a plurality of filtration elements that are disposed in the pressure vessel and filter raw water from the inside toward the outside, and are connected to one of the filtration elements, and filtered from the connected filtration element A backwashing type filtration device provided with a filtration unit comprising backwashing piping for backflowing water to wash the filtration element and switching means for switching the connection of the backwashing piping to the filtration element,
A deposit removing means for removing deposits formed on the filter element by supplying ozone to the filter element is provided,
A fresh water replacement mechanism in which the deposit removing means replaces water in the pressure vessel with fresh water;
An ozone supply mechanism for supplying ozone to the fresh water in the replaced pressure vessel;
An ozone circulation mechanism for forcibly circulating the fresh water supplied with ozone to a circulation line formed via the filtration element and the backwash pipe in the pressure vessel; Backwash type filtration device.   The backwashing type filtration apparatus according to claim 4, wherein the ozone supply mechanism is an ozone supply mechanism that includes a microbubble nozzle and supplies ozone microbubbles to the fresh water.   6. The backwashing type filtration apparatus according to claim 4 or 5, wherein the ozone circulation mechanism is an ozone circulation mechanism that circulates the fresh water supplied with ozone by causing the backwash pipe to flow backward. .   The backwash pipe is continuously connected to one filtration element for a predetermined time, and the backwash pipe is rotated so that the fresh water supplied with ozone is locally supplied to the predetermined filtration element. The backwashing type filtration apparatus according to any one of claims 4 to 6, further comprising a control unit that controls the apparatus.   The backwash type filtration apparatus according to any one of claims 1 to 7, wherein the raw water is seawater.

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