JPH07185234A - Method and apparatus for solid-liquid separation - Google Patents

Abstract

PURPOSE:To reduce the number of times of backwashing and to conduct efficiently stabilized separation by separating the raw liquid of primary loss removed of a high specific gravity portion into a small amount of the raw liquid of secondary concentration and a large amount of raw liquid of secondary loss by cross flow filtration carried out once. CONSTITUTION:The first electric valve 19, the first electromagnetic valve 29, and the fourth electromagnetic valve 38 are opened first, and raw liquid is fed to a cyclone 10 for liquid by driving a pump 17. The raw liquid is classified by centrifugal force so that the raw liquid of primary concentration containing a high specific gravity portion settles down. Besides, the raw liquid of primary loss containing a low specific gravity portion is led to an end of various passages 4 of a filtration module 1 from an overflow port 14 to be cross flow filtered. The raw liquid of secondary loss, associated with the cross flow filtration, is sent to relevant places from a filtrate chamber 7 through a raw liquid of secondary loss feed passage 31, and the raw liquid of secondary concentration is discharged through a raw liquid of secondary concentration discharge passage 39 into a bucket strainer 24, where the raw liquid and slurry are discharged respectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to SS (Suspend)
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid-liquid separation method and apparatus used for separation and purification of various stock solutions containing ed Solids; suspended solids), for example, pure water used for cleaning, filtration of coolant or groundwater of a processing machine, and regeneration treatment.

[0002]

2. Description of the Related Art Conventionally, as this type of solid-liquid separation method,
In order to cope with automation of the separation process and the like, cross flow filtration is generally performed. In cross-flow filtration, a cylindrical or spiral filter made of ceramics or polymer material having an asymmetric structure is inserted in the circulation path of the stock solution, and while the stock solution is flowing along the membrane surface, the filtrate (depleted stock solution) ) Is a solid-liquid separation method of vertically flowing out from the membrane surface.

[0003]

However, in the conventional solid-liquid separation method by cross-flow filtration, the filter is clogged by SS, so back pressure washing (back washing) must be performed frequently and the concentration is increased. While the magnification and the filtration pressure increase with time, there is a problem that the filtration flow rate decreases with time, and in particular, an abnormal increase in concentration or the like may occur at the final stage of filtration. Therefore, an object of the present invention is to provide a solid-liquid separation method and an apparatus therefor capable of reducing the number of backwashing steps and efficiently performing stable separation.

In order to solve the above problems, the solid-liquid separation method of the present invention classifies a stock solution containing SS into a primary concentrated stock solution containing a heavy specific gravity content and a primary impaired stock solution containing a low specific gravity content by centrifugal force. However, the above primary impaired stock solution is separated into a secondary concentrated solution and a secondary impaired stock solution by cross-flow filtration so that the outflow amount of the secondary concentrated stock solution is significantly smaller than the inflow amount of the primary impaired stock solution. is there. The solid-liquid separation device is used for carrying out the above method, and comprises a liquid cyclone for classifying a stock solution containing SS into a primary concentrated stock solution containing a heavy specific gravity content and a primary depleted stock solution containing a low specific gravity content, It is provided with a filtration module for cross-flow filtering the primary depleted stock solution classified by the liquid cyclone such that the outflow rate of the secondary concentrated stock solution is significantly smaller than the inflow rate. It is preferable that the solid-liquid separation device includes a primary side of the filtration module and a backwashing device capable of discharging a backwashing water amount equal to or more than the internal volume of the liquid cyclone. In addition, the solid-liquid separator uses SS from the primary concentrated stock solution classified by the hydrocyclone.
It is desirable to have a bucket strainer to separate the.

[0005]

In the above first and second means, the primary depleted stock solution from which the specific gravity is removed is separated into a small amount of secondary concentrated stock solution and a large amount of secondary depleted stock solution by one cross flow filtration. It In the third means, the gel and the primary concentrated stock solution, which cause the clogging of the filtration module, can be discharged to the outside of the system. Furthermore, in the fourth means, SS can be separated from the primary concentrated stock solution.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a flow chart showing an embodiment of the solid-liquid separation device of the present invention. In the figure, 1 is a filtration module, and this filtration module 1 has a cylindrical stainless steel casing 3 having flanges 2 at both ends, as shown in FIGS. 2 and 3, for example. A hexagonal columnar ceramics filter 5 having a large number of passages 4 passing through in the axial direction (vertical direction in FIG. 2).
However, they are coaxially fitted so as to form a filtrate chamber 7 with the cylindrical wall of the casing 3 via ring-shaped support fittings 6 attached to the flanges 2 at both ends. The ceramic filter 5 is made of high-purity alumina ceramics and has an asymmetric membrane structure in which the open pore diameter gradually increases from the inner side surface of each passage 4 serving as a filtering surface to the outer side. The diameter of the open pores on the side is 0.1 μm.

Further, nozzles 8 and 9 communicating with the filtrate chamber 7 are attached to the cylindrical walls at both ends of the casing 3, respectively. The upper nozzle 8 is mainly used as an outlet for the filtrate, and the lower nozzle 8 is mainly used as an inlet for a cleaning liquid for backwashing. Further, at one end (lower end in FIG. 2 and FIG. 3) of the casing 3, a hydrocyclone 10 integrally provided with the support fitting 6 is continuously provided, and the hydrocyclone 10 is provided with a cylindrical portion 11 and this. It is composed of a conical portion 12 that is continuous. The hydrocyclone 10 classifies an undiluted solution containing SS by centrifugal force into a primary concentrated undiluted solution containing heavy specific gravity and a primary depleted undiluted solution containing low specific gravity. Is provided tangentially, and the upper end opening of the cylindrical part 11 is used as an overflow port 14 to communicate with one end (lower end in FIG. 2) of each passage 4 of the ceramic filter 5. On the other hand, the lower end opening of the conical portion 12 serves as an underflow port 15. The other end of the casing 3 that communicates with the other end (upper end in FIG. 2) of each passage 4 of the ceramic filter 5 has a secondary concentrated stock solution outlet 16
It is said that.

The stock solution inlet 13 of the liquid cyclone 10
Is connected to the discharge port of the pump 17 for supplying the stock solution by the stock solution supply passage 18, and the stock solution supply passage 18 is provided with the first electric valve 19 and the first electric valve 19.
Before and after, the pressure switch 20 and the first pressure gauge 21 are branched and connected. Further, the underflow port 15 of the liquid cyclone 10 is connected to a bucket strainer 24 via a primary concentrated stock solution discharge passage 23 in which a second electric valve 22 is inserted. The bucket strainer 24 is for separating the primary concentrated stock solution into a stock solution and a slurry component. The separated stock solution, a stock solution outlet 25 for discharging the slurry content, and a drain port 26 are provided, and the slurry content is collected. A compressed air inlet 27 is provided for squeezing and cleaning the bucket strainer 24.

On the other hand, one nozzle 8 of the filtration module 1
To the first solenoid valve 2
The second depleted stock solution (filtrate) delivery passage 31 in which the flowmeter 9 and the flowmeter 30 are inserted in this order from the casing 3 side is connected, and the backwash cylinder 32 is connected to the other nozzle 9.
The backwash cylinder 32 stores the second impaired stock solution for backwashing the ceramic filter 5 and the like, and is on the primary side of the filtration module 1, that is, each passage 4 and the hydrocyclone 10.
Has a volume capable of discharging the amount of backwashing water that is greater than or equal to the volume of the fluid of FIG. In the compressed air passage 34, an exhaust passage 36 having a third solenoid valve 35 interposed is provided with a second solenoid valve 33 and a backwash cylinder 32.
It is branched and connected between and. The second and third solenoid valves 33, 35 are provided so as to be closed by a level switch 37 attached to the backwash cylinder 32. In addition, the secondary concentrated stock solution outlet 16 of the filtration module 1
Is a fourth solenoid valve 38 that can be restricted so that the outflow amount of the secondary concentrated undiluted solution from the secondary concentrated undiluted solution outlet 16 is significantly smaller than the inflow amount of the primary depleted undiluted solution from the overflow port 14 of the hydrocyclone 10. It is connected to the bucket strainer 24 by a secondary concentrated stock solution discharge path 39 inserted through. In FIG. 1, reference numeral 40 denotes a valve communicating with the filtrate chamber 7 for draining the second undiluted stock solution (filtrate) in the filtrate chamber 7.

In order to separate an undiluted solution containing SS using the solid-liquid separation device having the above structure, first, the first electric valve 19, the first electromagnetic valve 29 and the fourth electromagnetic valve 38 are opened to drive the pump 17. Then, the stock solution is supplied to the liquid cyclone 10. The stock solution that has flowed into the hydrocyclone 10 is classified by centrifugal force, and the primary concentrated stock solution containing the heavy specific gravity is settled at the bottom of the stock solution, while the primary depleted stock solution containing the low specific gravity is filtered from the overflow port 14. It is introduced into one end of various passages 4 of the module 1 and is cross-flow filtered. Along with this cross-flow filtration, the secondary depleted stock solution is sent from the filtrate chamber 7 to the required location via the secondary depleted stock solution delivery path 31, while the secondary concentrated stock solution is passed through the secondary concentrated solution discharge path 39. It is discharged to the bucket strainer 24, where it is separated into the undiluted solution and the slurry, and is ejected from the undiluted solution outlet 25 and the drain port 26, respectively. When the filtration efficiency of the ceramics filter 5 of the filtration module 1 decreases due to the progress of the above cross-flow filtration, the driving of the pump 17 is stopped, the first electric valve 19 is closed, and the second electric valve 22 is opened. , Second solenoid valve 3
3 is opened and closed to supply compressed air from the pressure source to the backwash cylinder 32, the secondary depleted stock solution in the backwash cylinder 32 is caused to flow into the filtrate chamber 7, and pulse pressure is applied to the secondary side of the filtration module 1. By doing so, the ceramic filter 5 is backwashed. By backwashing the ceramic filter 5, the gel separated from the inner surface of each passage 4 and the primary concentrated undiluted solution in the hydrocyclone 10 are discharged to the bucket strainer 24, and the undiluted solution and the slurry are separated as in the case of the secondary concentrated undiluted solution. And is discharged from the stock solution outlet 25 and the drain port 26. Note that the bucket strainer 24 is cleaned by supplying compressed air from the compressed air inlet 27 and squeezing SS or the like at the time of maintenance or the like in order to prevent clogging of the bucket strainer 24. Further, the inflow of the secondary depleted stock solution into the backwash cylinder 32 is performed during the filtration operation by the filtration module 1.

Here, the solid-liquid separation device (membrane area 0.6
m ² ), backwashing for 20 minutes cycle (compressed air pressure 5 k
While performing gf / cm ² and backwashing water amount 2l), solid-liquid separation of the electrical discharge machining liquid is performed for about 8 hours while the secondary concentrated stock solution amount is 1/5 of the primary depleted stock solution amount, while Using a conventional cross-flow filtration type solid-liquid separator (membrane area 0.6 m ² ) without a cyclone, backwashing was carried out in a cycle of 20 minutes (pulse backwashing, compressed air pressure 5 kgf / cm ² , backwashing injection water amount 0. When 2 l) was carried out and solid-liquid separation of the same stock solution was carried out for about 8 hours, the respective concentration ratios were as shown in FIG. 4, and the filtration pressure and the filtration flow rate were as shown in FIG. It was Therefore, according to the solid-liquid separation device of the present invention, the amount corresponding to the cross-flow circulation amount is the total of the primary concentrated stock solution and the primary impaired stock solution, and the running cost is reduced to 1/9 or less . Further, it can be understood that the concentration ratio, the filtration pressure and the filtration flow rate can be stabilized over a long period of time without causing a large change with time as in the conventional one.
Similarly, using a solid-liquid separator (membrane area 0.6 m ² )
20 minutes cycle backwash (compressed air pressure 5 kgf / cm ² ,
While performing backwashing water amount 2 l) and performing solid-liquid separation of the electric discharge machining liquid for about 8 hours so that the secondary concentrated stock solution amount becomes 1/5 of the primary depleted stock solution amount, the liquid cyclone 10 is not provided. When the solid-liquid separation of the electric discharge machining liquid was performed for about 8 hours using the above-mentioned solid-liquid separation device under the same conditions, the filtration pressure and the filtration flow rate were as shown in FIG. Therefore, as in the solid-liquid separation device according to the present invention, by providing a liquid cyclone, it becomes possible to perform selective filtration in the filtration module 1, and it is possible to stabilize the filtration pressure and the amount of filtrate over a long period of time. . Further, similarly, a solid-liquid separator (membrane area: 0.6 m ² ) was used to perform backwashing in a 20-minute cycle (compressed air pressure: 5 kgf / cm ² , backwashing water amount: 2 l) and the secondary concentrated stock solution amount was 1 The solid-liquid separation of the electric discharge machining liquid is performed for about 8 hours so as to be ⅕ of the next-depleted stock solution, while the secondary concentrated stock solution amount becomes zero, that is, the fourth solenoid valve 38 is closed to perform the solid-liquid separation. When the electric discharge machining liquid was subjected to solid-liquid separation in the same backwash cycle using the apparatus, the filtration pressure and the filtration flow rate were as shown in FIG. 7. Therefore, by discharging a part of the secondary concentrated stock solution to the bucket strainer 24 as in the solid-liquid separation device according to the present invention, the backwash interval can be extended and the concentration rate can be adjusted. (The concentration rate in one cycle has a correlation with the outflow amount of the secondary concentrated stock solution and the inflow amount of the primary depleted stock solution.) It can be seen that the filtration pressure and the filtration flow rate can be stabilized over a long period of time. .

In the above embodiment, the case where the filtration module 1 having the ceramic filter 5 having the asymmetric membrane structure is provided has been described, but the filtration module is not limited to the one having the ceramic filter 5, and for example, the asymmetrical structure is possible. It may have a polymer filter having a membrane or a composite membrane structure. Also, before the liquid cyclone,
A cartridge filter or an activated carbon filter may be installed together. Further, an ion-exchange resin cartridge may be inserted in the secondary depleted stock solution delivery path, which makes it possible to further expand the use of pure water for regeneration.

[0013]

As described above, according to the solid-liquid separation method and the apparatus thereof of the present invention, the primary depleted stock solution from which the specific gravity is removed is a small amount of the secondary concentrated stock solution by one cross-flow filtration. Since a large amount of secondary depleted stock solution is separated, the number of times of backwashing can be reduced, running costs can be greatly reduced, and stable separation can be efficiently performed. In addition, it is possible to discharge the gel and the primary concentrated stock solution, which cause the clogging of the filtration module, by providing the backwashing means that can discharge the backwashing water amount exceeding the inner volume of the filtration module and the liquid cyclone. Therefore, the filtration pressure and the filtration flow rate can be further stabilized. Furthermore, by providing a bucket strainer that separates SS from the primary concentrated stock solution that has been classified by the liquid cyclone, it is possible to separate SS from the primary concentrated stock solution. It can be unnecessary.

[Brief description of drawings]

FIG. 1 is a flow chart showing an embodiment of a solid-liquid separation device of the present invention.

FIG. 2 is a front view, in half cross-section, of a main part of the solid-liquid separation device shown in FIG.

FIG. 3 is a side view of a main part of the solid-liquid separation device shown in FIG.

FIG. 4 is an explanatory diagram showing a change in concentration ratio of the solid-liquid separator shown in FIG. 1 in comparison with a conventional one.

FIG. 5 is an explanatory diagram showing a comparison of a filtration pressure and a filtration flow rate between the solid-liquid separation apparatus shown in FIG. 1 and a conventional one different from the backwashing method.

FIG. 6 is an explanatory diagram showing a comparison between the filtration pressure and the filtration flow rate of the solid-liquid separation device shown in FIG. 1 and one without a liquid cyclone.

FIG. 7 is an explanatory diagram showing a comparison of the overpressure and the filtration flow rate of the solid-liquid separation device shown in FIG. 1 and a device for totally filtering using the solid-liquid separation device.

[Explanation of symbols]

 1 Filtration Module 10 Hydrocyclone 19 1st Motorized Valve 22 2nd Motorized Valve 24 Bucket Strainer 32 Backwash Cylinder 33 2nd Solenoid Valve 35 3rd Solenoid Valve 38 4th Solenoid Valve

Front Page Continuation (72) Inventor Yuji Yokotani No. 1 Minamifuji, Ogakie-cho, Kariya city, Aichi Toshiba Ceramics Co., Ltd. Kariya factory

Claims (4)

[Claims] 1. The primary depleted stock solution is subjected to secondary filtration by cross-flow filtration while classifying the stock solution containing SS into a primary concentrated stock solution containing a heavy specific gravity content and a primary depleted stock solution containing a low specific gravity content by centrifugal force. A solid-liquid separation method comprising separating a secondary concentrated stock solution and a secondary depleted stock solution such that the outflow rate of the concentrated stock solution is significantly smaller than the inflow rate of the primary depleted stock solution. 2. A liquid cyclone for classifying an undiluted solution containing SS into a primary concentrated undiluted solution containing a heavy specific gravity and a primary depleted undiluted solution containing a low specific gravity, and 1 classified by the hydrocyclone.
A solid-liquid separation device, comprising: a filtration module for performing cross-flow filtration of the secondary-depleted stock solution so that the outflow rate of the secondary-concentrated stock solution is significantly smaller than the inflow rate thereof. 3. The solid-liquid separation device according to claim 2, further comprising a backwashing device capable of discharging a backwashing-injected water amount equal to or more than the inner volume of the primary side of the filtration module and the liquid cyclone. 4. The solid-liquid separator according to claim 2, further comprising a bucket strainer for separating SS from the primary concentrated stock solution classified by the liquid cyclone.