Filtration apparatus and filtration method

Abstract

To provide efficient reduction of water content in slurry during dewatering treatment by filtration and to achieve an improved filling ratio of solid components in a filtration vessel over conventional methods.SOLUTION: A filtration apparatus 100 includes: a filtration vessel 1; two or more filters 2-1, 2-2, ..., 2-n disposed inside the filtration vessel 1; filter outlet pipelines 5-1, 5-2, ..., 5-n that lead filtrates produced in the respective filters 2-1, 2-2, ..., 2-n to the outside of the filtration vessel 1; and filter outlet flow regulating mechanisms 6-1, 6-2, ..., 6-n installed in the respective filter outlet pipelines 5-1, 5-2, ..., 5-n, the filters 2-1, 2-2, ..., 2-n each having a filtration section, the filtration sections being positioned at different height levels.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a filtration device and a filtration method. [Background technology]

[0002] Sludge generated in water purification processes and industrial wastewater treatment processes contains a large amount of water, so it is effective to dehydrate the sludge to reduce its volume when storing or disposing of it. Sludge generated in general industries has a high water content, and can contain several tens of times the volume of the solid components. A sludge-like substance that is a mixture of solid components and water is called a slurry.

[0003] Patent Document 1 discloses a filtration vessel having a plurality of cylindrical filtration membranes inside a shell having an inlet for a liquid to be filtered and an air vent, and each of the plurality of cylindrical filtration membranes has a cylindrical structure inside. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 11-90119 Summary of the Invention [Problem to be solved by the invention]

[0005] In a filtration device having multiple cylindrical filters arranged in parallel at vertical intervals inside a container (shell), when the container is sealed and the slurry poured onto the exterior of the cylindrical filters is pressurized or depressurized to filter the slurry, the filter is immersed in the slurry before filtration begins, and filtration progresses as the slurry is pressurized or depressurized. However, as filtration progresses, the level of the slurry in the container drops, and the top of the filter becomes exposed to the gas phase. As a result, pressure is released from the exposed part of the filter, which raises concerns about a decrease in the filtration rate of the slurry.

[0006] To prevent pressure from escaping from the exposed part of the filter, it is necessary to maintain the liquid level of the slurry filled in the filtration vessel above the top of the filter, which increases the frequency with which the operations of pressurizing or depressurizing the filtration vessel and filling the filtration vessel with slurry must be repeated.

[0007] To reduce the frequency of these recurrences, a low-height filter could be installed at the bottom of the filtering vessel so that the filter would not be exposed even as the slurry was filtered. However, this would increase the distance between the top of the filter and the ceiling of the filtering vessel, causing a thick layer of filtered material (hereinafter referred to as "cake") to accumulate on top of the filter, increasing filtration resistance. As a result, the slurry filling the space above the filter in the filtering vessel would not be sufficiently dewatered, resulting in a decrease in the solid loading rate in the filtering vessel.

[0008] The filtering container described in Patent Document 1 is not designed for use in a state where the filter is exposed.

[0009] An object of the present disclosure is to efficiently reduce the water content in a slurry during a slurry dewatering process by filtration, and to improve the filling rate of solid components in a filter vessel compared to conventional methods. [Means for solving the problem]

[0010] The filtration device of the present disclosure comprises a filtration container, two or more filters arranged inside the filtration container, filter outlet pipes that lead filtrate produced in each of the filters to the outside of the filtration container, and filter outlet flow rate adjustment mechanisms installed in each of the filter outlet pipes, wherein the filters have filtration sections, and when the height positions of the filtration sections of two of the filters are compared, at least a portion of the filtration section of one of the filters is arranged at a different height position from the filtration section of the other filter. [Effects of the Invention]

[0011] According to the present disclosure, in a slurry dewatering process by filtration, the water content of the slurry can be efficiently reduced, and the filling rate of the solid component in the filter vessel can be improved compared to conventional methods. Furthermore, according to the present disclosure, the frequency of repeating the operation of pressurizing or depressurizing the filter vessel and the operation of filling the filter vessel with slurry can be reduced.

[0012] Problems, configurations and effects other than those described above will become apparent from the following description of the embodiments. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a schematic diagram showing a preferred filtration device of Example 1. FIG. [Figure 2] FIG. 1 is a configuration diagram showing a preferred filtration device of Example 1. [Figure 3] FIG. 1 is a configuration diagram showing a preferred filtration device of Example 1. [Figure 4A] FIG. 4 is a cross-sectional view showing a filtering vessel constituting a filtering device of a comparative example. [Figure 4B] FIG. 2 is a cross-sectional view showing a filtering vessel constituting the filtering device of Example 1. [Figure 4C] 1 is a table showing parameters used to calculate the filtration rate and the amount of dewatering. [Figure 4D] 1 is a graph showing the change over time in filtration rate, which is a calculation result for Example 1 and Comparative Example. [Figure 4E] 1 is a graph showing the change over time in the amount of dehydration calculated in Example 1 and the comparative example. [Figure 5A] FIG. 10 is a cross-sectional view showing an example of a configuration for heating a filtration vessel. [Figure 5B] FIG. 2 is a cross-sectional view showing an example of a configuration for drying a slurry in a filtering vessel. [Figure 6A] FIG. 2 is a cross-sectional view showing an example of a storage state of a filtration vessel filled with a slurry. [Figure 6B] FIG. 10 is a cross-sectional view showing another example of a storage state of a filtration vessel filled with a slurry. [Figure 7]FIG. 10 is a schematic diagram showing an example of a preferred filtering device according to a second embodiment. [Figure 8A] FIG. 8 is a configuration diagram showing details of the filtering device of FIG. 7. [Figure 8B] FIG. 10 is a structural diagram showing another example of a preferred filtration device according to the second embodiment. [Figure 9] FIG. 8C is a configuration diagram showing details of the filtering device of FIG. 8B. DETAILED DESCRIPTION OF THE INVENTION

[0014] Examples of the filtration device and filtration method of the present disclosure will be described below with reference to the drawings. In the drawings used in this specification, identical or similar reference numerals are used to designate identical or corresponding components, and repeated description of these components may be omitted.

[0015] In this specification, the water content of the slurry or cake is referred to as the "moisture content." [Example]

[0016] A filtering device and a filtering method according to a first embodiment of the present disclosure will be described with reference to FIGS. 1 to 6B.

[0017] First, the overall configuration of the filtration device will be described with reference to Figures 1 and 2. Figures 1 and 2 show the configuration of the filtration device of this example.

[0018] (Configuration of filtration device) FIG. 1 is a schematic diagram showing a preferred filtration device of this embodiment.

[0019] The filtration device 100 shown in this figure includes a filtration vessel 1, a filter group 2, a filter outlet pipe group 5, and a filter outlet flow rate control valve group 6. The filtration vessel 1 houses the filter group 2. The filter group 2 is composed of multiple filters 2-1, 2-2, ..., 2-n. Each of the filters 2-1, 2-2, ..., 2-n is columnar (cylindrical) and is installed with its central axis in the horizontal direction. In other words, the filters 2-1, 2-2, ..., 2-n are oblong. The filters 2-1, 2-2, ..., 2-n are also arranged at different heights. The filters 2-1, 2-2, ..., 2-n are hollow, allowing filtrate to pass through from the outer surface to the interior. The filters 2-1, 2-2, ..., 2-n are preferably columnar (cylindrical).

[0020] Filtrate outlets of the filters 2-1, 2-2, ..., 2-n are connected to filter outlet pipes 5-1, 5-2, ..., 5-n, respectively. The filter outlet pipes 5-1, 5-2, ..., 5-n constitute a filter outlet pipe group 5. Filter outlet flow rate adjustment valves 6-1, 6-2, ..., 6-n (filter outlet flow rate adjustment mechanisms) are installed in the filter outlet pipes 5-1, 5-2, ..., 5-n, respectively. The filter outlet flow rate adjustment valves 6-1, 6-2, ..., 6-n constitute a filter outlet flow rate adjustment valve group 6. The filter outlet flow rate adjustment mechanisms may be open / close valves.

[0021] The slurry 3, which is the fluid to be filtered, is supplied to the filtration vessel 1 when the slurry tank outlet flow rate control valve 9 is opened.

[0022] A slurry 3, which is a fluid to be filtered, is retained in the lower part of the filtration vessel 1. The filter 2-1 is immersed in the slurry 3. On the other hand, the filters 2-2, ..., 2-n are in the gas phase above the slurry 3 and are not in contact with the slurry 3.

[0023] FIG. 2 is a diagram showing a preferred filtration device of this embodiment.

[0024] As shown in this figure, the filtration device 100 includes a slurry tank 7 and a filtrate tank 8 in addition to the configuration of FIG.

[0025] The slurry tank 7 is connected to the filtering vessel 1 via a pipe having a slurry tank outlet flow rate adjustment valve 9. Slurry 3 is stored in the slurry tank 7. The filtrate tank 8 is connected to the filtering vessel 1 via a filter outlet pipe group 5. In FIG. 2, the filtrate flowing through the filter outlet pipes 5-1, 5-2, ..., 5-n that make up the filter outlet pipe group 5 join together downstream of the filter outlet flow rate adjustment valves 6-1, 6-2, ..., 6-n, flows into the filtrate tank 8, and is stored there as the filtrate 4. Note that the filtrates from the filter outlet pipes 5-1, 5-2, ..., 5-n may also flow into the filtrate tank 8 without joining together.

[0026] The slurry 3 remaining in the lower part of the filtering vessel 1 is filtered by the filter 2-1 by opening the filter outlet flow rate control valve 6-1, and the filtrate flows into the filtrate tank 8 through the filter outlet pipe 5-1.

[0027] (Filtration method (pressure / decompression)) FIG. 3 is a diagram showing a preferred filtering device of this embodiment.

[0028] As shown in this figure, the filtration device 100 includes a pressurizer 10 and a decompressor 11 in addition to the configuration shown in FIG.

[0029] In FIG. 3, a pressurizer 10 is connected to a pipe having a slurry tank outlet flow rate control valve 9 so as to be able to pressurize the filtration vessel 1 .

[0030] The pressurizer 10 may also be connected to the slurry tank 7. In this case, the filtration vessel 1 can be pressurized via the slurry tank 7. A pump, a compressor, or the like is used as the pressurizer 10. By injecting air or other gas into the filtration vessel 1 using the pressurizer 10, the inside of the filtration vessel 1 can be pressurized and the slurry 3 can be filtered.

[0031] In this figure, a pressure reducer 11 is connected to the filtrate tank 8. A vacuum pump, a pressure reducing valve, or the like is used as the pressure reducer 11. By operating the pressure reducer 11, the filter outlet pipe group 5 and the filtrate tank 8 can be depressurized, thereby filtering the slurry 3. The filtration operation can be performed by using either the pressurizer 10 or the pressure reducer 11, but in some cases, both may be used.

[0032] In this figure, the filter outlet flow rate adjustment valve 6-1 of the filter outlet pipe 5-1 connected to the filter 2-1 immersed in the slurry 3 is open. On the other hand, the filter outlet flow rate adjustment valves 6-2, ..., 6-n of the filter outlet pipes 5-2, ..., 5-n connected to the filters 2-2, ..., 2-n in the gas phase above the slurry 3 are closed. This is because when at least one of the pressurizer 10 and the decompressor 11 is used, if the filter outlet flow rate adjustment valves 6-2, ..., 6-n are opened, gas passes through the filters 2-2, ..., 2-n in the gas phase, preventing pressure from being applied to the slurry 3 and preventing the filtration rate from being increased.

[0033] The filtration device of the present disclosure preferably includes a control unit that detects the filling amount or filling height of the slurry 3 in the filtration vessel 1, the pressure in the filtration vessel 1, the amount of slurry 3 in the slurry tank 7, the operating state of the pressurizer 10 and the decompressor 11, the flow rate of the filtrate in the filter outlet pipelines 5-1, 5-2, ..., 5-n, the amount of the filtrate 4 in the filtrate tank 8, etc., and issues commands to open or close the filter outlet flow rate control valves 6-1, 6-2, ..., 6-n, the slurry tank outlet flow rate control valve 9, etc.

[0034] (Detection of flow rate, etc. in the filter outlet pipe) In the filtration device 100 of this embodiment, it is effective to detect the filtration speed of the filters 2-1, 2-2, ..., 2-n and the clogging of the filters 2-1, 2-2, ..., 2-n in order to improve the filtration speed of the slurry 3. To detect the filtration speed and clogging of the filters 2-1, 2-2, ..., 2-n, it is effective to measure the flow rate and pressure of the liquid (filtrate 4) in each of the filter outlet pipes 5-1, 5-2, ..., 5-n.

[0035] In the pressure measurement, the pressure in the filtering vessel 1 and the filter outlet pipes 5-1, 5-2, ..., 5-n or the filtrate tank 8 is measured, and the pressure difference (differential pressure) is calculated. From this pressure difference, it is possible to determine whether pressure is being released from the filters 2-1, 2-2, ..., 2-n. By measuring the pressure in each of the filter outlet pipes 5-1, 5-2, ..., 5-n, it is possible to determine which of the filters 2-1, 2-2, ..., 2-n is releasing pressure. If the pressure difference is smaller than when the slurry 3 is injected to a height that immerses all of the filters 2-1, 2-2, ..., 2-n in the filtering vessel 1, it can be determined that pressure is being released from one of the filters 2-1, 2-2, ..., 2-n that is exposed to the gas phase.

[0036] Clogging of filters 2-1, 2-2, ..., 2-n can be detected by checking the filtrate flow rate in filter outlet pipes 5-1, 5-2, ..., 5-n and the pressure difference between the inside of filtration vessel 1 and the inside of filter outlet pipes 5-1, 5-2, ..., 5-n. For example, if filter 2-m among filters 2-1, 2-2, ..., 2-n becomes clogged, filtration of slurry 3 does not proceed through filter 2-m, resulting in a decrease in the flow rate through filter outlet pipe 5-m and an increase in the pressure difference between the inside of filtration vessel 1 and the inside of filter outlet pipe 5-m. Therefore, if the flow rate of filtrate 4 through filter outlet pipe 5-m decreases compared to immediately after filtration begins and the pressure difference between the inside of filtration vessel 1 and the inside of filter outlet pipe 5-m is large, it can be determined that filter 2-m is clogged.

[0037] It is desirable to use a flow meter or the like to measure the flow rate, and a pressure meter or the like to measure the pressure.

[0038] By installing the above-mentioned measuring equipment in each filter outlet pipe 5-1, 5-2, ..., 5-n and comparing the measured values at each filter outlet pipe 5-1, 5-2, ..., 5-n, it is possible to detect a decrease in the filtration speed or the occurrence of clogging in each filter 2-1, 2-2, ..., 2-n.

[0039] (Filtration method (1)) Here, an example of a method for filtering the slurry 3 using the filtering device 100 of this embodiment will be described with reference to Fig. 3. In this example, in the first stage, the slurry 3 is poured into the filtering vessel 1 so that all of the filters 2-1, 2-2, ..., 2-n are immersed in the slurry 3. Then, the filter outlet flow rate control valves 6-n corresponding to the filter 2-n installed at the top of the filtering vessel 1 are closed in order.

[0040] First, (1-1) all of the filter outlet flow rate control valves 6-1, 6-2, ..., 6-n of the filter outlet pipelines 5-1, 5-2, ..., 5-n are opened, and the slurry tank outlet flow rate control valve 9 is opened, and the slurry 3 is poured into the filtration vessel 1. At this time, the slurry 3 is poured to a height where all of the filtration sections of the filters 2-1, 2-2, ..., 2-n are immersed in the slurry 3.

[0041] Next, (1-2) pressurization of the filtration vessel 1 by the pressurizer 10 or depressurization of the filtrate tank 8 by the depressurizer 11 is performed. Alternatively, pressurization of the filtration vessel 1 by the pressurizer 10 and depressurization of the filtrate tank 8 by the depressurizer 11 may be performed simultaneously.

[0042] (1-3) As the filtration of the slurry 3 in the filtration vessel 1 progresses, the filtration section of one of the filters 2-1, 2-2, ..., 2-n arranged in the filtration vessel 1 becomes exposed, and the filtration rate decreases. When the filtration rate decreases, the flow control valves installed in the filter outlet pipes of the filters 2-1, 2-2, ..., 2-n whose filtration section is exposed are closed. Then, as the water level of the slurry 3 in the filtration vessel 1 decreases, the filter outlet flow control valves are closed in the same order, starting with the filter outlet flow control valve 6-n installed in the filter outlet pipe 5-n of the upper filter 2-n, and continuing to the filter outlet flow control valve 6-2 installed in the filter outlet pipe 5-2 of the lower filter 2-2.

[0043] By performing such an operation procedure for the filtration device 100, it is possible to prevent pressure from being released from the exposed filtration portion and suppress a decrease in the filtration rate.

[0044] In the above (1-1), all of the filter outlet flow rate adjustment valves 6-1, 6-2, ..., 6-n installed in the filter outlet pipelines 5-1, 5-2, ..., 5-n may be closed, and after the above (1-2), all of the filter outlet flow rate adjustment valves 6-1, 6-2, ..., 6-n installed in the filter outlet pipelines 5-1, 5-2, ..., 5-n may be opened.

[0045] (Filtration method (2)) Another example of a method for filtering a slurry 3 using the filtering device 100 of this embodiment will now be described with reference to Fig. 3. In this example, in the initial stage, it is not necessary to inject the slurry 3 into the filtering vessel 1 so that all of the filters 2-1, 2-2, ..., 2-n are immersed in the slurry 3. The filter outlet flow rate control valves 6-1 corresponding to the filter 2-1 installed at the bottom of the filtering vessel 1 are closed in order.

[0046] First, (2-1) all of the filter outlet flow rate control valves 6-1, 6-2, ..., 6-n installed in the filter outlet pipelines 5-1, 5-2, ..., 5-n are closed, and the slurry tank outlet flow rate control valve 9 is opened to inject the slurry 3 into the filtration vessel 1. At this time, the slurry 3 is injected to a height such that at least one filtering section of the filters 2-1, 2-2, ..., 2-n is immersed in the slurry 3.

[0047] Next, (2-2) pressurization of the filtration vessel 1 by the pressurizer 10 or depressurization of the filtrate tank 8 by the depressurizer 11 is performed. Alternatively, pressurization of the filtration vessel 1 by the pressurizer 10 and depressurization of the filtrate tank 8 by the depressurizer 11 may be performed simultaneously.

[0048] (2-3) Only the filter outlet flow rate adjusting valve 6-1 installed in the filter outlet pipe 5-1 of the filter 2-1 arranged at the bottom of the filtration vessel 1 is opened.

[0049] (2-4) The above steps (2-1) to (2-3) are repeated until the filtration rate in the lowermost filter 2-1 drops significantly or the filtration stops.

[0050] (2-5) If the filtration rate drops significantly or the filtration stops in the lowest filter 2-1, close the filter outlet flow rate control valve 6-1.

[0051] After the above steps (2-1) to (2-5) are completed, the slurry 3 is filtered using the filter 2-2 located above and closest to the lowest filter 2-1, using the same operational procedure as the filtration using the lowest filter 2-1.

[0052] This operating procedure of the filtration device 100 prevents pressure from escaping from the filtration section of the exposed filter, suppressing a decrease in the filtration rate. Furthermore, by filtering the slurry 3 using the filters arranged in order from the bottom up in the filtration vessel 1, the dewatered slurry 3 forms a hard cake and fills the filtration vessel 1 from the bottom up, allowing the slurry 3 to be dewatered efficiently. As a result, the moisture content of the cake ultimately remaining in the filtration vessel 1 can be reduced.

[0053] (Comparison of filtration speeds) The improvement in the filtration rate of the slurry 3 by the filtration device 100 of this embodiment will be described with reference to FIGS. 4A to 4E.

[0054] FIG. 4A is a cross-sectional view showing a filtering container constituting a filtering device of a comparative example.

[0055] Three columnar filters 2-1, 2-2, and 2-3 are installed vertically upward in the filtration vessel 1 shown in this diagram, and are arranged in parallel with a gap between them. The filters 2-1, 2-2, and 2-3 are installed at the bottom of the filtration vessel 1, and are entirely immersed in the slurry 3. Each of the filters 2-1, 2-2, and 2-3 is equipped with a pipe for sending the filtrate outside the filtration vessel 1, and a valve for opening and closing each pipe.

[0056] FIG. 4B is a cross-sectional view showing a filtering container constituting the filtering device of this embodiment.

[0057] In the filtration vessel 1 shown in this figure, three columnar filters 2-1, 2-2, and 2-3 are installed with their central axes directed horizontally, and are arranged in parallel with a gap between them.

[0058] Here, the results of calculations performed under predetermined conditions on the filtration rate and dewatering amount over time in the filtration vessels of FIGS. 4A and 4B are shown.

[0059] FIG. 4C is a table showing the parameters used to calculate the filtration rate and the amount of water removed.

[0060] As shown in this figure, the filtration rate per unit area of filters 2-1, 2-2, and 2-3 was set to 0.33 mL / (min cm 2 ), the dimensions of the filtration vessel 1 were φ200 × 400 mm, and the dimensions of the filters 2-1, 2-2, and 2-3 were φ75 × 360 mm. The time required for the operation of reducing the pressure in the pressurized filtration vessel 1 to atmospheric pressure, injecting the slurry 3 into the filtration vessel 1, and repressurizing the inside of the filtration vessel 1 was set to 5 minutes.

[0061] Fig. 4D is a graph showing the change in filtration rate over time, which is the calculation result for this example and the comparative example. The calculation was performed under the conditions shown in Fig. 4C. The example is represented by a solid line, and the comparative example is represented by a dashed line.

[0062] 4D, in the comparative example, with the inside of the filtration vessel 1 pressurized, approximately two minutes after filtration began, parts of the filters 2-1, 2-2, and 2-3 became exposed, causing the filtration rate to decrease. After this, the pressure inside the filtration vessel 1 was reduced to atmospheric pressure, and additional slurry 3 was injected into the filtration vessel 1. Then, the inside of the filtration vessel 1 was pressurized again, and all valves were opened to resume filtration.

[0063] In contrast, in this embodiment, when the pressure inside the filtration vessel 1 is pressurized, the filter 2-3 located at the top of the filtration vessel 1 becomes exposed approximately two minutes after filtration begins, but the filtration rate can be maintained by closing the valve corresponding to the filter 2-3.

[0064] After closing the filter outlet pipe 5-3 of the top filter 2-3, the filter 2-2 located at the second highest position in the filtration vessel 1 will be exposed in about 3 minutes, and the valve corresponding to the filter 2-2 will be closed.

[0065] By repeating this filtering procedure until the filter 2-1 located at the bottom in the filtering vessel 1 is exposed, the filtering rate can be maintained for a longer period of time than in the comparative example.

[0066] When all the filters 2-1, 2-2, and 2-3 in the filtration vessel 1 are exposed and the filtration rate decreases, the pressure inside the filtration vessel 1 is reduced to atmospheric pressure, and additional slurry 3 is injected into the filtration vessel 1. Then, the pressure inside the filtration vessel 1 is repressurized, and all the valves are opened to resume filtration.

[0067] The operation of injecting the slurry 3 takes from several minutes to several tens of minutes depending on the volume of the filtration vessel 1. Therefore, by lengthening the time during which the filtration rate can be maintained with one injection operation and reducing the number of injection operations as in this example, the time required for the entire filtration operation of the slurry 3 can be shortened.

[0068] Fig. 4E is a graph showing the change in dehydration amount over time, which is the calculation result for this example and the comparative example. Note that the calculation was performed under the conditions shown in Fig. 4C, as in Fig. 4D. The example is represented by a solid line, and the comparative example is represented by a dashed line.

[0069] As shown in FIG. 4E, in the comparative example, the time from the start of filtration until all of the filters 2-1, 2-2, and 2-3 are exposed is short, and the number of additional injection operations of the slurry 3 increases.

[0070] In contrast to this, in this example, even if the filtration rate decreases as the water level in the filtration vessel 1 decreases, the filtration operation can be continued, thereby reducing the number of times the additional injection operation of the slurry 3 is performed. As a result, in this example, the slurry 3 can be dewatered in a shorter time than in the comparative example.

[0071] (heating and drying of the filtration vessel) After the filtering vessel 1 has completed filtering of the slurry 3, it can be removed from the filtering device 100 and then further water content of the slurry 3 can be removed by heating or the like.

[0072] FIG. 5A is a cross-sectional view showing an example of a configuration for heating a filtration container.

[0073] In this figure, the filtering vessel 1 is installed on a heater 15, and the filtering vessel 1 is heated by the heater 15 while the filter outlet flow rate control valves 6-1, 6-2, and 6-3 of the filter outlet pipes 5-1, 5-2, and 5-3 are open. This causes the moisture contained in the slurry 3 in the filtering vessel 1 to evaporate and be released to the outside through the filter outlet pipes 5-1, 5-2, and 5-3. This allows the moisture in the slurry 3 to be further removed without scattering the powder of the filtered slurry 3 outside the filtering vessel 1.

[0074] FIG. 5B is a cross-sectional view showing an example of a configuration for drying the slurry in the filtration container.

[0075] In this figure, the filter outlet flow rate control valves 6-1, 6-2, and 6-3 of the filter outlet pipes 5-1, 5-2, and 5-3 are opened, and at least one of the filter outlet pipes 5-1, 5-2, and 5-3 is used as a gas outlet, while the others are used as gas inlets, to allow gas to flow into the filtering vessel 1. This allows the slurry 3 to be dried without causing powder of the filtered slurry 3 to scatter outside the filtering vessel 1. In this case, if the gas flowing into the filtering vessel 1 is a dry gas, the slurry 3 can be dried more effectively. Furthermore, as in FIG. 5A, the drying can be promoted by heating the filtering vessel 1 with a heater 15.

[0076] (Storage of filtration container) After the dehydration and drying of the slurry 3 has been completed, the filtering vessel 1 can be used as a storage vessel for the slurry 3 as is.

[0077] FIG. 6A is a cross-sectional view showing an example of a storage state of a filtration container filled with a slurry.

[0078] In this figure, the filter outlet flow rate control valves 6-1, 6-2, and 6-3 of the filter outlet pipes 5-1, 5-2, and 5-3 are closed, and the filtering vessel 1 is stored in a sealed state. If the filtering vessel 1 is stored as shown in this figure, it is possible to prevent toxic gases, etc., from being released outside the filtering vessel 1 if they are generated from the slurry 3.

[0079] FIG. 6B is a cross-sectional view showing another example of a storage state of a filtration vessel filled with a slurry.

[0080] In this figure, the filter outlet flow rate control valves 6-1, 6-2, and 6-3 of the filter outlet pipes 5-1, 5-2, and 5-3 are opened to store the slurry 3 in a state where it can be dried naturally. This prevents gas from being generated in the filtration vessel 1 during storage, which can increase the internal pressure and cause it to burst, or prevents flammable gases such as hydrogen from being generated, which can cause it to ignite or explode. [Example]

[0081] A second embodiment of the filtering device and filtering method of the present disclosure will be described with reference to FIGS.

[0082] First, the overall configuration of the filtration device will be described with reference to Figures 7 to 8B. Figures 7 to 8B show the configuration of the filtration device of this example.

[0083] (Configuration of filtration device) FIG. 7 is a schematic diagram showing an example of a preferred filtering device of this embodiment.

[0084] The filtration device 200 shown in this figure includes a filtration container 201, a filter group 202, a filter outlet pipe group 205, and a filter outlet flow rate adjustment valve group 206. The filtration container 201 has the filter group 202 therein. The filter group 202 is composed of a plurality of filters 202-1, 202-2, ..., 202-n. The filters 202-1, 202-2, ..., 202-n are each columnar and installed at the bottom (lower part) of the filtration container 201 with their central axes facing vertically upward. In other words, the filters 202-1, 202-2, ..., 202-n are vertically long. The filters 202-1, 202-2, ..., 202-n are arranged in parallel with a gap between them. Furthermore, the filters 202-1, 202-2, ..., 202-n have different heights (lengths). The filters 202-1, 202-2, . . . , 202-n are hollow, and allow the filtrate to pass through from the outer surface to the inside.

[0085] Filter outlet pipes 205-1, 205-2, ..., 205-n are individually connected to the filtrate outlets of the filters 202-1, 202-2, ..., 202-n, respectively. The filter outlet pipes 205-1, 205-2, ..., 205-n constitute a filter outlet pipe group 205. The filter outlet pipes 205-1, 205-2, ..., 205-n are provided with filter outlet flow rate adjustment valves 206-1, 206-2, ..., 206-n, respectively. The filter outlet flow rate adjustment valves 206-1, 206-2, ..., 206-n constitute a filter outlet flow rate adjustment valve group 206.

[0086] The filters 202-1, 202-2, ..., 202-n have a filtration section 213 that can filter the slurry 203. The filters 202-2, ..., 202-n have, in addition to the filtration section 213, a non-filtration section 214 that does not filter the slurry 203. The filters 202-2, ..., 202-n have the filtration section 213 in their upper parts and the non-filtration section 214 in their lower parts. On the other hand, the filter 202-1 does not have the non-filtration section 214. The filter 202-1 is substantially composed of only the filtration section 213.

[0087] In this figure, the entire filter 202-1 is covered with the slurry 203. On the other hand, only the lower portions of the filters 202-2, ..., 202-n are covered with the slurry 203. The filtration sections 213 located above the filters 202-2, ..., 202-n are at least partially exposed to the gas phase. For this reason, among the filter outlet flow rate control valves 206-1, 206-2, ..., 206-n, the filter outlet flow rate control valves 206-2, ..., 206-n are closed. This is because if the filter outlet flow rate control valves 206-2, ..., 206-n were opened, gas in the gas phase would pass through the filtration sections 213 of the filters 202-2, ..., 202-n and escape to the filter outlet pipes 205-2, ..., 205-n, preventing the slurry 203 from being pressurized.

[0088] FIG. 8A is a configuration diagram showing details of the filtering device of FIG.

[0089] In Fig. 8A, a slurry tank 207 is connected to a filtering vessel 201 via a pipe. A slurry tank outlet flow rate control valve 209 is provided on the pipe connecting the filtering vessel 201 and the slurry tank 207. A slurry 203 is stored in the slurry tank 207. By increasing the aperture of the slurry tank outlet flow rate control valve 209, the slurry 203 flows from the slurry tank 207 into the filtering vessel 201.

[0090] The filter outlet pipes 205-1, 205-2, ..., 205-n are connected to a filtrate tank 208. The filtrate 204 that has passed through the filters 202-1, 202-2, ..., 202-n flows into the filtrate tank 208 and is stored therein. The filtrates flowing through the filter outlet pipes 205-1, 205-2, ..., 205-n are configured to join together before flowing into the filtrate tank 208. Note that the filtrates from the filter outlet pipes 205-1, 205-2, ..., 205-n may also be configured to flow into the filtrate tank 208 without joining together.

[0091] FIG. 8B is a structural diagram showing another example of a suitable filtering device according to this embodiment.

[0092] 8A, the filters 202-1, 202-2, ..., 202-n are vertically long, but are different in that they face downward. That is, the filters 202-1, 202-2, ..., 202-n are disposed on the upper part (ceiling part) of the filtration container 201.

[0093] 8A, by arranging the filters 202-1, 202-2, ..., 202-n in the vertical direction, the filtration container 201 can be heated, dried, and stored simply by turning the filtration container 201 upside down. Also, in the configuration shown in Fig. 8B, the filtration container 201 can be heated, dried, and stored without changing the orientation of the filtration container 201.

[0094] Other configurations and operations of this embodiment are almost the same as those of the filtration device and filtration method of Example 1, and details thereof will be omitted.

[0095] FIG. 9 is a configuration diagram showing details of the filtering device of FIG. 8B.

[0096] 9, a pressurizer 210 and a decompressor 211 are added to the configuration of FIG. 8B. The pressurizer 210 is connected to a pipe connecting the slurry tank 207 and the filtration vessel 201. The decompressor 211 is connected to the filtrate tank 208.

[0097] Filters 202-1, 202-2, ..., 202-n have a filtration section 213 that can filter the slurry 203. Of filters 202-1, 202-2, ..., 202-n, except for filter 202-n, in addition to the filtration section 213, they also have a non-filtration section 214 that does not filter the slurry 203. Filters other than filter 202-n have the filtration section 213 in their lower part and the non-filtration section 214 in their upper part. On the other hand, filter 202-n does not have the non-filtration section 214. Filter 202-n is essentially composed of only the filtration section 213.

[0098] In this figure, the entire filtration section 213 of filter 202-1 is covered with slurry 203. On the other hand, at least a portion of the filtration section 213 of filters 202-2, ..., 202-n is exposed to the gas phase. For this reason, among the filter outlet flow rate adjustment valves 206-1, 206-2, ..., 206-n, the filter outlet flow rate adjustment valves 206-2, ..., 206-n are closed. This is because if the filter outlet flow rate adjustment valves 206-2, ..., 206-n were opened, gas in the gas phase would pass through the filtration section 213 of the filters 202-2, ..., 202-n and escape to the filter outlet pipes 205-2, ..., 205-n, preventing the slurry 203 from being pressurized.

[0099] (Filtration method (1)) Here, an example of a method for filtering the slurry 203 using the filtering device 200 of this embodiment will be described.

[0100] First, (1-1) all of the filter outlet flow rate control valves 206-1, 206-2, ..., 206-n of the filter outlet pipelines 205-1, 205-2, ..., 205-n are opened, and the slurry tank outlet flow rate control valve 209 is opened, and the slurry 203 is poured into the filtration vessel 201. At this time, the slurry 203 is poured to a height where at least one filtration section 213 of the filters 202-1, 202-2, ..., 202-n is immersed in the slurry 203.

[0101] Next, (1-2) the filtration vessel 201 is pressurized by the pressurizer 210 or the filtrate tank 208 is depressurized by the depressurizer 211. Alternatively, the filtration vessel 201 may be pressurized by the pressurizer 210 and the filtrate tank 208 may be depressurized by the depressurizer 211 simultaneously.

[0102] (1-3) As the filtration of the slurry 203 in the filtration vessel 201 progresses, the filtration section 213 of any of the filters 202-1, 202-2, ..., 202-n arranged in the filtration vessel 201 becomes exposed, and the filtration rate decreases. When the filtration rate decreases, the filter outlet flow rate adjustment valves installed in the filter outlet pipes of the filters 202-1, 202-2, ..., 202-n whose filtration section 213 is exposed are closed. Then, as the water level of the slurry 203 in the filtration vessel 201 decreases, the filter outlet flow rate adjustment valves are similarly closed, starting with the filter outlet flow rate adjustment valve 206-n installed in the filter outlet pipe 205-n of the filter 202-n whose filtration section 213 is installed at the top, through to the filter outlet flow rate adjustment valve 206-2 installed in the filter outlet pipe 205-2 of the filter 202-2 whose filtration section 213 is installed at the bottom.

[0103] By performing such an operation procedure for the filtration device 200, it is possible to prevent pressure from being released from the exposed filtration section 213 and suppress a decrease in the filtration rate.

[0104] In the above (1-1), all of the filter outlet flow rate adjustment valves 206-1, 206-2, ..., 206-n installed in the filter outlet pipes 205-1, 205-2, ..., 205-n may be closed, and after the above (1-2), all of the filter outlet flow rate adjustment valves 206-1, 206-2, ..., 206-n installed in the filter outlet pipes 205-1, 205-2, ..., 205-n may be opened.

[0105] (Filtration method (2)) Another example of the method for filtering the slurry 203 using the filtering device 200 of this embodiment will be described with reference to Fig. 9. In this example, in the initial stage, it is not necessary to pour the slurry 203 into the filtering vessel 201 so that all of the filters 202-1, 202-2, ..., 202-n are immersed in the slurry 203. The filter outlet flow rate control valves 206-1 corresponding to the filter 202-1 installed at the bottom of the filtering vessel 201 are closed in order.

[0106] First, (2-1) all of the filter outlet flow rate control valves 206-1, 206-2, ..., 206-n installed in the filter outlet pipelines 205-1, 205-2, ..., 205-n are closed, and the slurry tank outlet flow rate control valve 209 is opened to inject the slurry 203 into the filtration vessel 201. At this time, the slurry 203 is injected to a height such that at least one or more filtration sections 213 of the filters 202-1, 202-2, ..., 202-n are immersed in the slurry 203.

[0107] Next, (2-2) the filtration vessel 201 is pressurized by the pressurizer 210 or the filtrate tank 208 is depressurized by the depressurizer 211. Alternatively, the filtration vessel 201 may be pressurized by the pressurizer 210 and the filtrate tank 208 may be depressurized by the depressurizer 211 simultaneously.

[0108] (2-3) Only the filter outlet flow rate adjustment valve 206-1 installed in the filter outlet pipe 205-1 of the filter 202-1 whose filtration unit 213 is located at the bottom of the filtration container 201 is opened.

[0109] (2-4) Repeat the above steps (2-1) to (2-3) until the filtration rate in the filter 202-1 drops significantly or the filtration stops.

[0110] (2-5) When a significant drop in the filtration rate or a cessation of filtration occurs in the filter 202-1, the filter outlet flow rate adjustment valve 206-1 is closed.

[0111] After the above steps (2-1) to (2-5) are completed, the slurry 203 is filtered using the filter 202-2 that is disposed above and closest to the filter 202-1, in the same procedure as the filtration using the filter 202-1.

[0112] This operating procedure of the filtration device 200 prevents pressure from being released from the filtration section 213 of the exposed filter, thereby suppressing a decrease in the filtration rate. Furthermore, by filtering the slurry 203 using filters in order, starting with the filter whose filtration section 213 is located at the bottom of the filtration vessel 201, the dewatered slurry 203 forms a hard cake and fills the filtration vessel 201 from the bottom to the top, allowing the slurry 203 to be dewatered efficiently. As a result, the moisture content of the cake ultimately remaining in the filtration vessel 201 can be reduced.

[0113] Even when the filter is arranged vertically as in the filtering device and filtering method of this embodiment, substantially the same effects as those of the filtering device and filtering method of the first embodiment can be obtained.

[0114] <Other> Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above embodiments, and various modifications are possible within the scope of the present disclosure. For example, the present disclosure is not necessarily limited to those including all of the configurations of the above embodiments. Part of the configuration of an embodiment may be replaced with another configuration, part of the configuration of an embodiment may be added to another form, or part of the configuration of an embodiment may be omitted.

[0115] Preferred embodiments of the present disclosure will be described below.

[0116] The control unit detects at least one of data on the amount or height of the fluid inside the filtration vessel and data on the pressure inside the filtration vessel, and issues a command to open or close the filter outlet flow rate adjustment valve based on the data.

[0117] At least two of the filters are installed so that their central axes are oriented horizontally.

[0118] At least two of the filters are installed so that their central axes are oriented vertically.

[0119] The control unit issues a command to inject fluid into the filtration vessel until the entire filtering portion of the filter is immersed in the fluid, open the filter outlet flow rate adjustment valve, and perform at least one of pressurizing and depressurizing the filtration vessel.

[0120] The control unit injects fluid into the filtration container until the entirety of at least one filtration section of the filters is immersed in the fluid, opens the filter outlet flow control valve in the filter outlet pipe corresponding to the filter immersed in the fluid, and issues a command to perform at least one of pressurizing and depressurizing the filtration container.

[0121] The control unit detects clogging of the filter or exposure to the gas phase, and issues a command to close the filter outlet flow rate adjustment valve in the filter outlet pipe corresponding to the filter. [Explanation of symbols]

[0122] 1, 201: filtration vessel, 2, 202: filter group, 2-1, 2-2, 2-3, ..., 2-n, 202-1, 202-2, ..., 202-n: filters, 3, 203: slurry, 4, 204: filtrate, 5, 205: filter outlet pipe group, 5-1, 5-2, 5-3, ..., 5-n, 205-1, 205-2, ..., 205-n: filter outlet pipe, 6, 206: filter outlet flow rate adjustment Valve group, 6-1, 6-2, 6-3, ..., 6-n, 206-1, 206-2, ..., 206-n: filter outlet flow rate control valves, 7, 207: slurry tank, 8, 208: filtrate tank, 9, 209: slurry tank outlet flow rate control valves, 10, 210: pressurizers, 11, 211: pressure reducers, 15: heaters, 100, 200: filtration equipment, 213: filtration section, 214: non-filtration section.

Claims

1. A filtering vessel; two or more filters disposed within the filtration vessel; a filter outlet line for leading the filtrate produced in each of the filters to the outside of the filtration vessel; a filter outlet flow rate adjusting mechanism installed in each of the filter outlet pipes, The filter has a filtering portion, A filtration device in which, when comparing the height positions of the filtration sections of two of the filters, at least a portion of the filtration section of one of the filters is positioned at a different height position from the filtration section of the other of the filters.

2. Further comprising a control unit, 2. The filtration device according to claim 1, wherein the control unit detects at least one of data on the amount or height of fluid filled inside the filtration vessel and data on the pressure inside the filtration vessel, and issues a command to adjust the flow rate of the filter outlet pipe based on the data.

3. The filtration device of claim 1 , wherein each of the filters is pillar-shaped.

4. 2. The filtering device according to claim 1, wherein at least two of the filters are installed so that their central axes are oriented horizontally.

5. 2. The filtering device according to claim 1, wherein at least two of the filters are installed so that their central axes are oriented vertically.

6. The filtration device according to claim 1 , wherein the filter outlet flow rate adjusting mechanism is a flow rate adjusting valve or an on-off valve.

7. A filtering vessel; two or more filters disposed within the filtration vessel; a filter outlet line for leading the filtrate produced in each of the filters to the outside of the filtration vessel; a filter outlet flow rate adjusting mechanism installed in each of the filter outlet pipes; a control unit, The filter has a filtering portion, A filtration method using a filtration device, wherein, when comparing height positions of the filtration units of two of the filters, at least a part of the filtration unit of one of the filters is disposed at a different height position from the filtration unit of the other of the filters, The control unit detects at least one of data on the amount or height of fluid filled inside the filtration vessel and data on the pressure inside the filtration vessel, and issues a command to adjust the flow rate of the filter outlet pipe based on the data.

8. The filtration method according to claim 7 , wherein the filter outlet flow rate adjusting mechanism is a filter outlet flow rate adjusting valve or an on-off valve.

9. The control unit 9. The filtration method according to claim 7, further comprising the steps of: injecting the fluid into the interior of the filtration vessel until the entire filtration portion of the filter is immersed in the fluid; opening the filter outlet flow rate adjustment mechanism; and issuing a command to perform at least one of pressurizing and depressurizing the filtration vessel.

10. The control unit 9. The filtration method according to claim 7, further comprising the steps of: injecting the fluid into the interior of the filtration container until the entire filtration section of at least one of the filters is immersed in the fluid; opening the filter outlet flow rate adjustment mechanism of the filter outlet pipe corresponding to the filter immersed in the fluid; and issuing a command to perform at least one of pressurizing and depressurizing the filtration container.

11. The control unit 11. The filtering method according to claim 9, further comprising detecting clogging of the filter or exposure to a gas phase, and issuing a command to close the filter outlet flow rate adjusting mechanism of the filter outlet pipe corresponding to the filter.

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