JPH09215901A - Filtration equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the recovery efficiency of oil components by a method in which fluid is circulated in one way through a filter with a crossflow type membrane, the concentrated oil components of the fluid is recovered, and the separated liquid of low concentration is passed through a bypass. SOLUTION: A filtration equipment S1 is equipped with a filter 122 with a crossflow type membrane, and oil-water mixed fluid is circulated in one way. A supply route 103 which supplies the fluid from a washing tank 101 and bypasses 1a, 1b, in which floating oil recovery means 2 is installed, are provided. The fluid is circulated, and the filtrate from the filter 122 is supplied to the washing tank through a route 131. In this way, oil emulsion with oil components concentrated is introduced into the recovery means 2 and, after the oil components being removed, returned to a circulation route K1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filtering device for filtering a fluid to be filtered mixed with oil and water, and in particular, an oil to be filtered which is concentrated in a circulation path by a cross flow type membrane-utilizing type filtration means. The present invention relates to a technique for improving the efficiency of floating oil recovery means for removing components.

[0002]

2. Description of the Related Art Hitherto, a membrane-utilizing filtration means using a microfiltration membrane or an ultrafiltration membrane has been adopted as a filtration device used for reusing a cleaning liquid containing water or a cleaning agent and treating waste water. There are things that are doing.

[0003] This is a cleaning liquid that does not contain oil content, which is obtained by filtering a cleaning liquid containing oil which is to be filtered through a membrane having fine pores that are much smaller than the size of an oil droplet, and separating oil and water. Is what you get.

That is, for example, a large number of hollow fiber membranes 12 are provided as membrane-utilizing filtration means provided in the filtration device shown in FIG.
A hollow fiber membrane module 123 using a bundle of 4 as an ultrafiltration membrane is used, and a stock solution (for example, 50 to 200) supplied by a pump 121 provided in a circulation path 120 is used.
ppm) in parallel with the inner surface of the membrane wall of the hollow fiber membrane 124, and a part of the stock solution at that time permeates the membrane wall and is filtered to obtain a permeate (0 to 1 ppm).

On the other hand, the liquid that has not been filtered remains in the circulation path 12
0 is recirculated and concentrated, and the concentrated liquid is discharged as a concentrated liquid (100 to 300 ppm).

In this way, oil and water are separated to obtain an oil-free cleaning liquid.

However, the oil concentration of the above-mentioned concentrated liquid is low, and the oil-water separation efficiency is not good. On the contrary, when the concentration is high, the oil content adheres to the membrane surface of the hollow fiber membrane 124 to form an oil membrane without separating, and the pores of the membrane are closed, so that the filtration ability is deteriorated.

From these, the concentration will be controlled,
It is necessary to finely control the flow rate (the set value of flow rate depends on the concentration). Therefore, there is a floating oil recovery means shown in FIG. 11 as a means for separating oil water containing a high concentration of oil.

That is, the floating oil recovery means 112 is provided with a retention tank 112a. The stock solution is supplied and retained in the retention tank 112a, and the oil is floated and separated due to the difference in specific gravity. Is discharged. Retention tank 1 shown in FIG.
Reference numeral 12a includes a filler 112e such as a coalescer filter, which promotes separation due to a difference in specific gravity. That is, when passing through the filler 112e, the oil droplets are aggregated and easily floated.

The liquid permeated by the filler 112e is discharged as a permeated liquid (100 to 20 ppm).

In this way, oil and water are separated.

However, in the floating oil recovery means 112, when the stock solution is an oil emulsion solution in which oil having a very small oil droplet size is emulsified and dispersed, the oil is difficult to float and the oil passes through the filler 112e. Oil remains on the permeate side.

Therefore, a floating oil recovery means for separating high-concentration oil water is provided in the preceding stage, and a membrane-utilizing filtration means capable of separating low-concentration oil water such as an oil emulsion liquid is provided in the latter stage, and each of the above-mentioned respective Filtration devices that compensate for the drawbacks have been proposed.

(Conventional Example 1) FIG. 12 shows a conventional example 1 of the conventional filtering device. This filtering device 100 removes dirt and oil adhering to the work W101 to be cleaned. A cleaning liquid L101 containing water and a cleaning agent as main components is put in the cleaning tank 101, and the work W101 is put therein. By immersing, the physical action such as ultrasonic waves, stirring, and shaking
It removes dirt and oil. Here, 102 is illustrated as an ultrasonic oscillator.

When the works W101 are continuously and successively put into the cleaning tank 101, the cleaning liquid L in the cleaning tank 101 is filled.
Since the oil concentration of 101 increases and the cleaning ability for the work W101 decreases, the filtration device 100 is equipped with the filtration means described below.

This is due to the two-stage circulation path provided downstream of the supply path 103 for supplying the fluid to be filtered from the cleaning tank 101.

The first stage (previous stage) is through the concentration path 110, and is provided with a pump 111 and floating oil recovery means 112.

The second stage (the latter stage) is based on the circulation path 120. The circulation path 12 is provided with a pump 121 having a larger flow rate than the pump 111 and a membrane utilization type filtration means 122.
0 is circulated through the cleaning liquid L101 to be filtered, and the cleaning liquid (membrane permeated liquid) obtained by separating the oil by the membrane-utilizing type filtration means 122 and returning the filtered cleaning liquid is returned to the cleaning tank 101 through the return path 131.
To put it back inside.

Although the principle of the floating oil recovery means 112 has been described above, as will be described in detail, as shown in FIG. 13, the cleaning liquid L11 makes it easy for the oil droplets L111a to come into contact with each other in the retention tank 112a.
0 is accumulated, and minute oil droplets (for example, several to several tens of μm) are collected due to the difference in specific gravity between the water component L112 and the oil droplet L111a, and floated upward as large oil droplets (for example, several hundreds of μm) to wash in the cleaning liquid L101. Water component L112 and oil component L111
Is to be separated.

In the retention tank 112a, as shown in FIG.
The oil component L111 is separated in the order of FIG. 13 (b) and FIG. 13 (c), and only the oil component L111 is discharged.

Although not shown in FIG. 12, a microfine fiber structure coalescer filter is provided in the retention tank 112a, and the cleaning liquid L10 is attached to the coalescer filter.
In some cases, the oil droplet L111a is made even larger by transmitting 1 to promote the specific gravity difference separation.

Next, as the membrane-utilizing type filtering means 122,
As described above, the hollow fiber membrane module 123 that uses a bundle of a large number of hollow fiber membranes 124 as an ultrafiltration membrane is used, and the pump 12 provided in the circulation path 120 is used.
The cleaning liquid supplied in 1 flows in parallel to the inner surface of the membrane wall of the hollow fiber membrane 124, and a part of the cleaning liquid at that time is of a cross-flow type which permeates the membrane wall and is filtered.

In the cross-flow type, in order to operate the membrane-utilizing type filtration means 122 for a long time, the hollow fiber membrane module 123 is provided in the circulation path 120 of the cleaning liquid to be filtered, and the flow is always parallel to the membrane. This is a method for preventing contamination and clogging of the membrane surface by minimizing.

The cleaning liquid that has not permeated the hollow fiber membrane 124 in the hollow fiber membrane module 123 recirculates through the circulation path 120. The concentration of the oil component in the cleaning liquid gradually increases due to this circulation, so that a part of the cleaning liquid passes through the concentration path flow rate adjusting valve 113 and flows into the concentration path 110, and the oil component is separated by the floating oil recovery means 112.

In the filtering device 100, therefore, the oil component (oil emulsion liquid) which is emulsified and dispersed in the cleaning liquid is also discharged as it circulates through the above-mentioned concentration and circulation paths 110 and 120. Is designed so that the amount of oil brought in by the oil is equal to the amount of oil component discharged from the floating oil recovery means 112. At the same time, the concentration of oil components in the cleaning tank 101, the concentration and circulation paths 110, 120 is also increased. It is stable within the range of each predetermined value.

The constituent elements included in FIG. 12 which are not explained are omitted, but 125 is a flow rate adjusting valve of the membrane-utilizing type filtering means 122, and 126 and 127 are hollow fibers. These are the primary and secondary pressure gauges of the membrane module 123.

Although the filtration device 100 employs the cross-flow type membrane-utilizing filtration means 122, when the filtration is continued for a long time, the hollow fiber membrane module may be generated due to oil components, suspended pollutants and the like. The membrane of the large number of hollow fiber membranes 123, 123, is clogged.

Therefore, at a predetermined interval (for example, 10 to 60)
Once every minute), the backwash valve 132 is switched to feed the high-pressure air or the membrane permeate to the hollow fiber membrane module 123 (referred to as backwash).

(Conventional Example 2) FIG. 14 shows a filtering apparatus according to Conventional Example 2 having an equivalent circuit to the above-mentioned Conventional Example 1, and this filtering apparatus will be described below. The same components as those in the above-mentioned conventional example 1 will be described with the same reference numerals.

Reference numeral 100 denotes a filtering device which is an oil-water separating device, and a floating oil collecting means 112 which is a floating oil removing device is provided in a front stage, and a hollow membrane-using filter means which is a membrane-utilizing oil-water separating device is provided in a subsequent stage. The hollow fiber membrane module 123 is a combination with a fiber membrane module 123, and the hollow fiber membrane module 123 is provided in a circulation path 120 provided with a pump 121 that is a circulation pump.
The concentrated liquid from No. 3 is returned to the upstream side of the floating oil recovery means 112, and the concentration path 110 that connects the downstream side of the floating oil recovery means 112 to the upstream side of the pump 121 is provided.

The floating oil collecting means 112 collects high-concentration oil water in which oil droplets easily come into contact with each other in the retention tank 112a as described above, and minute oil droplets stick to each other due to the difference in specific gravity between water and oil droplets. It is a large oil droplet that floats up and separates water and oil.

The hollow fiber membrane module 123 uses a bundle of a large number of hollow fiber membranes 124 as described above as a microfiltration or ultrafiltration membrane, and is supplied by a pump 121 provided in the circulation path 120. Oil and water hollow fiber membrane 12
It is a cross-flow type in which it flows parallel to the surface of the membrane wall of No. 4 and a part of the oil water at that time is filtered by passing through the membrane wall.

The filtered permeate is passed through a return path 131 formed by a permeate pipe to a cleaning tank 101 described later.
It is supplied to and reused.

In FIG. 14, reference numeral 101 denotes a cleaning tank as a cleaning means in which the cleaning liquid is stored as described above and the work W101 to which the object to be cleaned such as oil adheres is corroded. The cleaning tank 101 and the floating oil recovery means 112 are connected by a supply path 103, and a pump 111, which is a pressurizing pump, is provided in the middle of the connection. This pump 111
At, the cleaning liquid contaminated with the oil overflowed from the cleaning tank 101 is supplied to the floating oil recovery means 112.

The low-concentration oil water separated to some extent by the floating oil recovery means 112 is supplied to the downstream circulation path 120 by the pump 121 via the pipe 141 and is crossed by the hollow fiber membrane module 123. After flow filtration, only water and the cleaning agent permeate and return to the cleaning tank 101 via the return path 131.

Further, on the upstream side of the floating oil recovery means 112, a pipe 142 through which high-concentration oil water from the hollow fiber membrane module 123 flows is connected to the concentration path 11 on the upstream side of the pump 111.
They are connected via a pipe 143 forming 0. The pipe 143 is provided with a concentration path flow rate adjustment valve 113 for adjusting the amount of the concentrated liquid to be returned to the floating oil recovery means 112.

As a result, the oil concentrated in the circulation path 120 is processed again by the floating oil recovery means 112 via the concentration path flow rate adjusting valve 113, and is discharged as floating oil in the discharge pipe 112b.
Are separated and removed via.

In the example of the filtration device 100 shown in FIG. 14, a float switch 112c is provided in the retention tank 112a of the floating oil recovery means 112, and the interface between the floated oil and water is sensed to be provided in the discharge pipe 112b. Valve 112d
Open and close to drain the oil.

At this time, the concentration path flow rate control valve 113 provided in the upstream pipe 143 of the pump 111 connected between the downstream pipe 142 of the hollow fiber membrane module 123 of the circulation path 120 and the supply route 103. Is completely closed, the oil water is concentrated in the circulation path 120, and the concentration thereof increases with time, resulting in high-concentration oil water. This is done because the emulsion is easily floated and separated by concentrating.

Therefore, the opening / closing amount of the concentration path flow rate adjusting valve 113 provided in the pipe 143 in the concentration path 110 is adjusted, and the pump 111 supplies high-concentration oil water to the floating oil recovery means 112. As described above, the oil / water separated to some extent and having a low concentration is again supplied to the hollow fiber membrane module 123 by the pump 121, and the oil / water is separated again.

In this way, the oil-water separation process is repeated in the concentration path 110.

(Prior Art Example 3) Then, the applicant has already applied for a filtration device in which the floating oil recovery means is provided in the preceding stage and the membrane-utilizing type filtration means is provided in the latter stage (Practical application 5-).
63678). The filtering device will be described with reference to FIG. The same components as those in the above-mentioned conventional examples are designated by the same reference numerals and will be described below.

That is, in the circulation path 120, the pump 121
Strainer 14 for rough dust removal for protection of
4 and a throttle valve 145 for adjusting the flow rate and the pressure. In the figure, 146 is a valve for sampling the permeated liquid that has permeated the hollow fiber membrane module 123.

In the concentration path 110, the concentrated liquid flow rate regulator 1 provided on the downstream side of the concentration path flow rate adjustment valve 113.
47, a check valve 148 provided on the downstream side of the concentrated liquid flow rate regulator 147, and a check valve 149 provided between the floating oil recovery means 112 and the circulation path 120.

Further, in the return path 131, the cleaning tank 10
Permeate flow rate adjusting valve 15 for adjusting the flow rate of permeate to be returned to 1.
0 and a check valve 151 provided on the downstream side of the permeate flow rate adjusting valve 150.

The floating oil recovery means 112 and the cleaning tank 1
01, the low-concentration return path 152 for returning the low-concentration oil water separated to some extent by the floating oil recovery means 112.
have. The low-concentration return path 152 is equipped with a flow rate adjusting valve 153 for adjusting the flow rate.

Since other configurations and operations are the same as those of the above-mentioned conventional examples, the same components are designated by the same reference numerals in the drawings, and the description thereof will be omitted.

(Conventional example 4) FIG. 16 shows a conventional example 4
In the filtration device according to the above-mentioned conventional example 3,
Two hollow fiber membrane modules 124 as membrane-utilizing filtration means are provided in parallel in the circulation path 120. Other configurations and operations are the same as those of the conventional example 3 described above,
The same components are given the same reference numerals in the drawings, and the description thereof will be omitted.

[0049]

By the way, as described above, the concentration of the oil component of the cleaning liquid flowing into each path and configuration of the filtration device 100 according to each conventional example is stable within a predetermined value range. However, the following description will be made on behalf of the filtration device of the first conventional example. When the filtration device 100 is stable, the circulation passage 120 has an oil component concentration of about 50% and the cleaning tank 101 has an oil component concentration of about 1%. It is generally designed.

Then, assuming that the circulation flow rate of the cleaning liquid in the circulation path 120 is 70 (l / min), this is the capacity of the pump 121, and the membrane utilization type filtration means 122 at this circulation flow rate.
Assuming that the flow rate of the membrane permeate from the membrane is 2 (l / min), the same 2 (l / min) as the flow rate of the membrane permeate separated from the cleaning tank 101 through the supply route 103 is concentrated in the concentrating route. Will be supplied to 110.

The flow rate in the concentrating path 110 is mainly set to match the processing capacity of the floating oil recovery means 112. Here, the flow rate is 5 (l / min), and the pump 111 is used.
The ability of is also adjusted to this and is set to 5 (l / min).

Here, paying attention to the floating oil recovery means 112 arranged in the concentration path 110, the floating oil recovery means 1
When the oil component concentration B flowing into 12 is calculated, it can be obtained as in the following mathematical formula 1.

[0053]

(1) (A−a) / A · C _J + a / A · C _T = B where A is the flow rate of the pump 111 (l / min), and a is the supply flow rate from the cleaning tank 101 (l / min). ), C _J is the oil component concentration (%) of the concentration path 110, and C _T is the cleaning tank 101.
Is the oil component concentration (%), and B is the oil component concentration (%) of the cleaning liquid flowing into the floating oil recovery means 112.

Then, in the above equation 1, A = 5, a = 2,
Substituting C _J = 50 and C _T = 1 to obtain B, the oil component concentration B of the cleaning liquid flowing into the floating oil recovery means 112 is about 30 (%).

Therefore, the circulation path 120 is 50
The cleaning liquid concentrated to the oil component concentration of (%) is reduced in oil component concentration by the cleaning liquid having a low oil component concentration supplied from the cleaning tank 101, and flows into the floating oil recovery means 112. The oil recovery efficiency of the oil recovery means 112 is reduced.

That is, in the case of the prior art, the floating oil collecting means is installed before the membrane-utilizing filtering means,
The oil emulsion liquid concentrated in the circulation path is returned to the upstream side of the floating oil recovery means, mixed with the cleaning liquid having a low concentration as the oil emulsion liquid, and then supplied to the floating oil recovery means. The solution concentrated in (1) will be diluted with the washing solution, which is not suitable for filtering only the oil emulsion solution (separation of oil / water).

When the flow rate of the pump 111 is increased in order to prevent the oil component concentration from being lowered by the cleaning liquid having a low oil component concentration supplied from the cleaning tank 101, the oil water in the floating oil recovery means 112 is increased. The separation speed does not catch up and the effective oil recovery function cannot be exerted.

Further, the pump 111 is a floating oil recovery means in a state in which the cleaning liquid whose flow rate is regulated by the concentration path flow control valve 113 and whose pressure is reduced and the cleaning liquid supplied from the cleaning tank 101 and having a low oil component concentration are mixed. It is for supplying pressure to 112, and without this pump, it is impossible to return (and supply) the cleaning liquid to the circulation path 120 via the floating oil recovery means 112.

Therefore, the prior art is suitable for separating high-concentration oily water that is relatively easy to separate from water, and is also suitable for the case of only an oil emulsion liquid that is difficult to separate from low-concentration water. A filtration device is required.

The present invention has been made to solve the above-mentioned problems of the prior art, and the purpose thereof is to be used even in the case of only an oil emulsion liquid which is difficult to separate from water, and the floating oil recovery means It is to provide a filtering device having a simple structure in which a cleaning liquid containing a high oil component concentration is made to flow into the interior to improve the recovery efficiency of the oil component, and a pump for conveying the cleaning liquid to the floating oil recovery means is unnecessary. .

[0061]

In order to achieve the above object, according to the present invention, a cross-flow type membrane-utilizing filtration means and a filtration target fluid mixed with oil-water in the membrane-utilizing filtration means are provided. A circulation path that circulates in the direction, a supply path that is connected to this circulation path and that supplies the fluid to be filtered, and a floating oil recovery means that separates and recovers the oil component of the fluid to be filtered concentrated in the circulation path. , The floating oil recovery means is connected so that the filtered fluid concentrated from the circulation path flows in and the low-concentration separated liquid from the floating oil recovery means flows out to either the circulation path or the supply path. And a bypass path to perform the operation.

It is also preferable that the bypass path is connected from the high voltage side to the low voltage side.

Further, it is also preferable that the bypass path is provided with a flow rate control valve for controlling the flow rate of the fluid to be filtered flowing into the floating oil recovery means.

Furthermore, it is also preferable to provide dust removing means on at least one of the above-mentioned paths.

In the filtration device having the above-mentioned structure, the fluid to be filtered having a high oil component concentration in the circulation path is directly flown into the floating oil recovery means by the bypass path, and the oil component removal efficiency is improved. That is, the oil emulsion liquid, which is difficult to separate from water, is not supplied as the fluid to be filtered from the supply path to the floating oil recovery means, and the oil emulsion solution is concentrated in the circulation path to have a high concentration, and the oil emulsion liquid having a high concentration that is easily separated from the water is obtained. Since the oil water flows into the floating oil recovery means and is separated, the filtration device is suitable even when only the oil emulsion liquid is used.

Further, for example, by connecting the bypass path from the inlet side of the membrane-utilizing filter means to the outlet side of the membrane-utilizing filter means or the supply path in the circulation path, the bypass passage is connected from the high pressure side to the low pressure side. As a result, a pump for flowing a high-concentration fluid to be filtered into the floating oil recovery means for oil-water separation is not required,
The device configuration can be simplified.

Further, by providing a flow rate control valve for controlling the flow rate of the fluid to be filtered in the bypass path and controlling the opening / closing amount of the valve, the oil / water separation efficiency of the floating oil recovery means is further improved, and under optimum conditions. Oil-water separation is performed.

Therefore, the oil concentration of the concentrated liquid decreases as it passes through the floating oil recovery means. Then, when the carry-in speed of the device and the oil discharge speed of the floating oil recovery means match, the oil content concentration of the concentrated liquid in the circulation path becomes steady.

As a result, the cross-flow type membrane-utilizing type filtration means in the circulation path can be operated with a constant load, and the apparatus can be stabilized. Therefore, it is possible to prevent a decrease in the permeation flux of the membrane-utilizing type filtration means.

Furthermore, by providing the dust removing means in at least one of the above-mentioned routes, the dust that has entered the route is removed, and the membrane-utilizing type filtering means and the floating oil collecting means have filters. It can prevent things from clogging. This makes it possible to further stabilize the device.

[0071]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on the illustrated embodiment.

(Embodiment 1) FIG. 1 is a first embodiment schematically showing a filtering device to which the present invention is applied. In this filtering device S1, the filtering device 1 described in the prior art is used.
The same components as those of No. 00 are assigned the same reference numerals and treated as the same as those of the conventional art, and the detailed description thereof will be omitted.

The filtering device S1 comprises a cross-flow type membrane-utilizing type filtering means 122. The membrane-utilizing filtration means 122 is a hollow fiber membrane module 123, and is a bundle of a large number of hollow fiber membranes 124.

The material of the hollow fiber membrane 124 is PS
F (Polysulfone), PVA (Polyvinyl alcohol), PVB (Polyvinyl butyral), PVF (Polyvinyl formal), EVA (Eval), PEI (Polyetherimide), PAI (Polyamideimide), P
I (polyimide), PPS (polyphenyl sulfone),
PES (polyether sulfone), PVDF (polyvinylidene fluoride), PAN (polyacrylonitrile), P
Examples include MMA (polymethylmethacrylate) and PA (polyamide).

K1 is a circulation path for cross-flowing the fluid to be filtered mixed with oil and water, and the fluid to be filtered which has returned from the outlet side 122a to the circulation path K1 without passing through the membrane of the membrane-utilizing type filtration means 122 is indicated by an arrow A1. , A2, A3, A
4, A5 is circulated according to the one-way path.

In this circulation path K1, 113 is a flow rate control valve, 121 is a pump, and 125 is a flow rate control valve for controlling the flow rate of the fluid to be filtered which flows into the membrane-utilizing filtration means 122.

Further, 103 is a cleaning tank 101 for the fluid to be filtered.
Is a supply path for supplying the fluid from the circulation path K1 to the circulation path K1 and supplies the same amount as the fluid to be filtered, which has been reduced through the membrane from the circulation path K1.

Reference numerals 1a and 1b denote bypass paths connecting from the outlet side 122a of the membrane-utilizing type filtering means 122 of the circulation path K1 to the downstream side of the connecting portion 103a of the supply path 103, and in the bypass paths 1a and 1b. Floating oil recovery means 2
Is arranged. 2a is a discharge port for discharging the recovered floating oil.

Reference numeral 3 is a flow rate control valve that enables the maximum amount of floating oil to be recovered by controlling the flow rate of the fluid to be filtered which flows into the floating oil recovery means 2.

When the filtration device S1 having the above-described configuration is operated, the fluid to be filtered, which is a mixture of oil and water, starts to circulate mainly in the circulation route K1 by the pump 121, and the membrane permeation liquid is generated by the membrane-utilizing type filtration means 122. The membrane permeate is supplied to the cleaning tank 101 via the return path 131.

Further, as the fluid to be filtered circulates in the circulation route K1, the oil component concentration of the oil emulsion liquid becomes higher, and the floating oil recovery means 2 is put into the optimum operating state from the bypass route 1a by the flow control valve 3. The fluid to be filtered having a flow rate controlled to directly flows in to remove the oil component and maintain the oil component concentration within a certain range.

Here, the oil component concentration in each component under the same operating conditions as in the prior art example 1 will be determined. That is,
Assuming that the circulation route K1 is stable at an oil component concentration of about 50%, the floating oil recovery means 2 will directly flow into the floating oil recovery means 2 an oil emulsion liquid having an oil component concentration of about 50%.

Therefore, in the floating oil recovery means 2, as in the conventional case, the fluid to be filtered having an oil component concentration (oil content concentration) lower than the oil component concentration of the circulating fluid to be filtered, that is, the oil from the washing tank 101 is used. The emulsion liquid never flows in,
The floating oil recovery efficiency is improved.

As a result, the filtering device having the above structure is suitable only for the oil emulsion liquid which is difficult to separate from water.

Further, since the circulation path K1 and the floating oil recovery means 2 are directly connected by the bypass path 1a, the pressure loss of the fluid to be filtered is small, and a special pump or the like for conveying the fluid to be filtered to the floating oil recovery means 2 is used. Is unnecessary.

(Embodiment 2) FIG. 2 shows a filtering device according to Embodiment 2 of the present invention.
1 is an equivalent circuit to the filtering device according to the first embodiment. Therefore, the filtering device S1 according to the present embodiment
In the figure, the same components as those of the first embodiment are designated by the same reference numerals in the drawings, and the description of the configuration and operation thereof will be omitted.

However, the control of the flow control valve 3 will be described.

That is, by adjusting the opening degree of the flow control valve 3 provided in the bypass path 1a, the floating oil recovery efficiency (oil-water separation efficiency) of the floating oil recovery means 2 is increased as described above, and the oil discharge When the speed and the oil carry-in speed to the device match, the oil content concentration of the concentrated liquid in the circulation route K1 becomes steady.

At this time, the flow control valve 3 is set so that the amount of the fluid to be filtered sent from the pump 121 is about 10: 1 to 100: 1 in the floating oil recovery means 2. adjust.

As a result, the hollow fiber membrane module 123 as the membrane-utilizing type filtration means 122 in the circulation route K1 can be operated with a constant load, and a decrease in permeation flux can be prevented.

As described above, since the high-concentration oil emulsion liquid can be sent to the floating oil recovery means 2, the oil can be efficiently discharged, and as a result, the oil content concentration in the circulation route K1 to the hollow fiber membrane module 123 can be increased. It can be kept low and the permeate flow rate can be secured (conversely, in order to set the oil concentration in the circulation path K1 to the conventional example 3 = the present embodiment, the discharge amount from the floating oil recovery means 2 should be increased. There must be.
→ Increased amount of waste liquid).

Then, the filtering device S1 according to the present embodiment
In this case, a filter, a strainer or the like as dust removing means is provided in the portion of the supply path 103 indicated by an arrow in the figure, or a dust removing means is similarly provided in the circulation path K1 within the dotted line in the figure. A bypass pipe may be newly provided and installed there.

As described above, by providing the dust removing means in the supply path 103, it is possible to prevent the intrusion of impurities into the circulation path K1.

Further, by providing the dust collecting means in the circulation route K1, the foreign substances that have entered the circulation route K1 are captured, and the hollow fiber membrane module 123 and the floating oil recovery means 2 (in this case, a filter (not shown)) Can be prevented from being clogged.

Further, a valve may be provided at the portion of the circulation path K1 indicated by the arrow in the figure to secure the pressure to be inserted into the floating oil recovery means 2.

(Embodiment 3) FIG. 3 shows a filtering device according to Embodiment 3 of the present invention. In each of the above embodiments, the bypass path is connected from the outlet side 122a of the membrane-utilizing type filtration means 122 to the downstream side of the connecting portion 103a of the supply path 103, but in the present embodiment, the circulation path K is used.
The bypass paths 1A and 1B connected from the inlet side 122b of the membrane-utilizing type filtration means 122 to the outlet side 122a of the membrane-utilizing type filtration means 122, in which so-called floating oil collecting means 2 are arranged in parallel. Is.

As described above, in the filtering device S1 according to the present embodiment, the bypass paths 1A and 1B are connected from the inlet side 122b to the outlet side 122a of the membrane-utilizing type filtering means 122. 1A and 1B are connected from the inlet side 122b, which is the high-pressure side, to the outlet side 122a, which is the low-pressure side, of the membrane-utilizing type filtration means 122, whereby the fluid to be filtered having a high concentration is collected for floating oil recovery for oil-water separation. Since no pump is needed to insert into means 2,
The device configuration can be simplified.

The flow rate control valve 3 is connected to the bypass path 1A.
It is provided in.

Further, as in the second embodiment, a filter, a strainer or the like as a dust removing means is provided in the portion of the supply path 103 indicated by an arrow in the figure, or the circulation path K1 and the bypass path 1 within the dotted line in the figure are the same. It is decided to provide a means to remove dust. By the way, a bypass pipe is newly installed,
You may install it there.

Further, a valve (see the flow rate adjusting valve 125 of FIG. 4 showing an embodiment to be described later) may be provided in the portion of the circulation path K1 indicated by an arrow in the figure to secure the pressure to be inserted into the floating oil recovery means 2. good.

Here, the filtering device S1 according to the present embodiment
4 shows an example thereof, the same components as those in the above-mentioned respective embodiments are designated by the same reference numerals, and the description thereof will be omitted. Below, the filtration apparatus S1 which concerns on an Example is demonstrated.

(Example) First, the bypass paths 1A and 1B
Floating oil recovery means 2 and bypass path 1 provided in the
Will be described.

The floating oil recovery means 2 is of a type provided with a coalescer filter 2b as an oil coarsening means, and the coalescer filter 2b is provided in the retention tank 2c. By allowing the liquid to permeate through the coalescer filter 2b, which is this ultrafine fiber structure, the oil droplet diameter is increased and the specific gravity difference separation is promoted.

A float switch 2d is provided at a predetermined position on the upper side of the retention tank 2c, and the float switch 2d senses the interface between the floating oil and water. Also,
When it is difficult to detect the interface, a timer is used to discharge the liquid at regular intervals.

Further, a discharge pipe 2e for discharging the floating oil in the concentrated liquid to the outside is connected above the retention tank 2c, and a valve 2f is provided in the discharge pipe 2e. The valve 2f is preferably a motor valve.
This is because if the valve is a spring-based opening / closing valve, the oil may be clogged with the spring portion or the like to prevent the opening / closing from being performed reliably.

A tank 2g for storing waste oil is provided on the discharge port 2a side, and a float switch 2h is provided at a predetermined upper position in the tank 2g.

Bypass path 1 of bypass path 1
A is provided with a constant flow rate adjusting valve 4, a throttle valve 5 for adjusting the flow rate and pressure in the path, and a primary side pressure gauge 6 for the floating oil recovery means 2. Reference numeral 7 in the figure denotes a secondary side pressure gauge 7 of the floating oil recovery means 2.

Further, the bypass passage 1B is also provided with a throttle valve 8 for adjusting the flow rate and pressure in the bypass passage 1B.

Next, the circulation route K1 and the membrane-utilizing type filtering means 122 will be described.

In the figure, reference numeral 9 shown in the circulation path K1 is an expansion joint, which is required when detaching the hollow fiber membrane module 123 for replacement or the like. Reference numeral 10 in the figure is a throttle valve. Further, reference numeral 11 in the drawing indicates a pressure switch.

An air vent path 12 for venting air is connected to the circulation path K1. This air vent path 12
An on-off valve 13 is provided in the.

Next, the return path 131 will be described.

A check valve 14 is provided in the return path 131. Solenoid valves 15 and 16 are provided on the upstream and downstream sides of the check valve 14, and the solenoid valve 1 on the downstream side is provided.
At 6, the amount returned to the cleaning tank 101 is controlled.

The solenoid valve 15 is a three-way valve, as shown in detail in a separate frame on the left side of FIG.
Directional valve is air source, outside (atmosphere), return path 131
Are connected to the α portion of the pipe connected to.

By means of this solenoid valve 15, the hollow fiber membrane module 123 as the membrane-utilizing type filtration means 122.
At the time of backwashing, air flows from the air source into the hollow fiber membrane module 123 through the return path 131, and at the end of backwashing, the air flows out to remove the air used for backwashing. .

Next, the part of the supply path 103 will be described.

A buffer tank 17 having a strainer 36 for removing coarse dust and the like is provided inside the supply path 103.
Is provided. The buffer tank 17 stores the concentrated liquid when the hollow fiber membrane module 2 is backwashed, and is a priming tank for starting the apparatus when the washing tank 101 is below the supply path 103. Further, the buffer tank 17 is provided with a pressure gauge 18 and a valve 19.

Further, on the upstream side of the buffer tank 17, a throttle valve 20 and a solenoid valve 21 as a shutoff valve for preventing liquid leakage due to abnormal piping are provided.
1 to the circulation path K from the cleaning liquid L101 which is the fluid to be filtered
The flow rate supplied to No. 1 is controlled.

In the present embodiment, the bypass path 1 is provided with dust removing means.

This dust removing means is a wind filter unit 23 provided in the bypass pipe 22 connecting from the bypass passage 1A to the bypass passage 1B. The wind filter 23 'is an ultrafine fiber structure which constitutes the dust removing means in the cylindrical housing. Is provided. Further, the wind filter unit 23 has a primary pressure gauge 24 and a valve 25. A strainer or a cyclone may be used as the dust removing means.

Furthermore, the bypass pipe 22 is provided with a throttle valve 26 for adjusting the flow rate and pressure in the pipe,
A secondary pressure gauge 27 is provided on the upstream side.

Further, in the figure, reference numerals 28 to 32 denote open / close valves, which allow the liquid in the pipe in which the open / close valves 28 to 32 are provided to be discharged.

Further, reference numeral 33 in the figure denotes a portion of a table on which the filtering device S1 is placed. A float switch 34 is provided at a predetermined position of the table 33, and an opening / closing valve 35 is provided at a lower end portion of the table 33. The liquid can be discharged to the outside when the liquid leaks and collects due to a device trouble.

(Fourth Embodiment) FIG. 5 shows a filtering device according to a fourth embodiment of the present invention.
1 is an equivalent circuit to the filtering device according to the third embodiment. Therefore, the filtering device S1 according to the present embodiment
In the figure, the same components as those in the third embodiment are designated by the same reference numerals in the drawings, and the description of the configuration and operation will be omitted.

In this embodiment, the check valve 35 is provided in the supply path 103.

In the filtering device S1 according to this embodiment, an example of specific flow rate and concentration in each path will be shown.

First, the pump 121 is set to 100 L / min ×
It will be 20 m. As a result, the cleaning liquid L in the supply path 103
The stock solution, which is 101, has a flow rate of 10 L / min and a concentration of 10
It is supplied to the circulation route K1 as 0 to 200 ppm. At this time, the flow rate of the permeated liquid obtained is also 10 L / min,
The flow rate of the liquid flowing through the bypass paths 1a and 1b is also 10 L / m
in.

As a result, the concentration of the liquid in the bypass passage 1a connected to the floating oil collecting means 2 becomes 150 ppm, and this liquid is separated into oil and water by the floating oil collecting means 2 to some extent, and the bypass on the downstream side thereof. The concentration of the liquid flowing through the route 1b becomes 50 ppm, and the low concentration liquid is recirculated to the circulation route K1. Then, it is concentrated in the circulation route K1 to reach the above-mentioned concentration of 150 ppm.

On the other hand, the oil content of 1 to 2 g / min is discharged from the discharge port 2a of the floating oil collecting means 2.

(Fifth Embodiment) FIG. 6 shows a filtering device according to a fifth embodiment of the present invention.
1 is an equivalent circuit to the filtering device according to the first and second embodiments. Therefore, in the filtering device S1 according to the present embodiment, the same components as those in the first and second embodiments are designated by the same reference numerals in the drawings, and the description of the configuration and operation will be omitted. Further, the same components as those in the above-described embodiment are designated by the same reference numerals, and the description of the configuration and operation will be omitted.

In this embodiment, since the bypass path 1 is connected from the outlet side 122a of the hollow fiber membrane module 123 in the circulation path K1 to the downstream side of the connecting portion 103a of the supply path 103, the pressure In order to supply oil water to the floating oil recovery means 2 in the bypass path 1 from the outlet side 122a of the hollow fiber membrane module 123 having a low temperature, the pressurizing pump 38 may be required.

Therefore, as shown in the third embodiment, the bypass paths 1A and 1B connecting from the inlet side 122b of the hollow fiber membrane module 123 to the outlet side 122a are used so that the inlet side 122b having a high pressure is It will be automatically discharged to the circulation path K1, and the pressurizing pump 38 will be unnecessary.

The filtering device S1 is shown in FIG. 7 as a sixth embodiment.

(Embodiment 6) That is, this filtering device S
1 is an equivalent circuit to the filtering device according to the third embodiment. Therefore, the filtering device S1 according to the present embodiment
In the figure, the same components as those in the third embodiment and the examples are denoted by the same reference numerals in the drawings, and the description of the configuration and the action will be omitted.

That is, the bypass passage 1 in the filtering device S1 is connected from the high pressure side to the low pressure side in the circulation passage K1.

In the present embodiment, a strainer 39 as a dust removing means is provided in the bypass path 1A on the upstream side of the floating oil collecting means 2 for protecting the coalescer filter 2b to remove large foreign matters and the like. Prevents clogging.

Similarly, the strainer 40 is also provided in the supply path 103 to prevent the entry of foreign matters into the circulation path K1.

A flow rate control valve 3 for adjusting the flow rate in the bypass path 1 is provided upstream of the strainer 39 in the bypass path 1A.

In the present embodiment, the oil water supplied by the pump 121 of the circulation path K1 is the oil water in the circulation path K1 in the retention tank 2c via the bypass path 1A on the relatively high pressure side of the circulation path K1. After entering the coalescer filter 2b, the oil and water are separated to some extent from the bottom of the retention tank 2c as described above, and are automatically discharged to the circulation path K1 via the bypass pipe 1B.

At this time, by adjusting the opening degree of the flow rate control valve 3 provided in the bypass path 1A, the oil / water recovery efficiency (oil / water separation efficiency) of the floating oil recovery means 2 is increased as described above, and the discharge speed thereof is increased. And the oil bringing-in speed into the apparatus are equalized, the oil concentration of the concentrated liquid in the circulation route K1 becomes steady. At this time, the ratio of the oil water flowing into the circulation path K1 and the bypass path 1 is set to 10: 1 to 200: 1.

As a result, the hollow fiber membrane module 123 in the circulation route K1 can be operated with a constant load, and a decrease in permeation flux can be prevented.

The bypass route 1 is connected from the high pressure side to the low pressure side in the circulation route K1, and when the flow loss to the floating oil recovery means 2 is insufficient or the pressure loss due to the clogging of the strainer 39 increases, the circulation route K1. By adjusting the flow rate control valve 125 of No. 2, it is possible to secure a sufficient supply pressure and flow rate to the bypass path 1. Therefore, power for separating oil and water such as the pressurizing pump 38 is not required, and the device configuration can be simplified. Can be planned.

Up to the sixth embodiment, as the bypass path 1, the low-concentration separated liquid from the floating oil recovery means 2 is made to flow out to the circulation path K1 which is the downstream side of the connecting portion 103a of the supply path 103. Although the connection is described as an example, according to the present invention, it suffices if the concentrated liquid directly flows into the floating oil recovery means 2 from the circulation path K1, and thus the low-concentration separated liquid from the floating oil recovery means 2 is used. And the connecting portion 103 as in the seventh embodiment shown in FIG. 8 and the eighth embodiment shown in FIG.
The bypass path 1 may be connected so as to flow out to the supply path 103 on the upstream side of a.

(Embodiment 7) That is, in Embodiment 7 shown in FIG. 8, the membrane-utilizing filtration means 12 is used in the circulation route K1.
The bypass passages 1a and 1b are connected to the floating oil collecting means 2 from the outlet side 122a of the second passage so that the separated low-concentration fluid to be filtered flows out to the supply passage 103. Since other configurations and operations are the same as those of the above-described respective embodiments, the same components are designated by the same reference numerals in the drawings, and description thereof will be omitted.

(Embodiment 8) In Embodiment 8 shown in FIG. 9, the membrane-utilizing filtration means 12 in the circulation route K1 is used.
The bypass passages 1A and 1B are connected to the floating oil recovery means 2 from the inlet side 122b of the second passage so that the separated low concentration fluid to be filtered flows out to the supply passage 103. Since other configurations and operations are the same as those of the above-described respective embodiments, the same components are designated by the same reference numerals in the drawings, and description thereof will be omitted.

[0146]

EFFECTS OF THE INVENTION The present invention has the above-mentioned structure and action, and the fluid to be filtered having a high oil component concentration in the circulation path is directly flown into the floating oil recovery means by the bypass path to improve the oil component removal efficiency. To do. That is, the low concentration oil emulsion liquid that is difficult to separate from water as the fluid to be filtered is not supplied from the supply route to the floating oil recovery means, and the oil emulsion liquid is concentrated in the circulation route to a high concentration, and this high concentration oil water is Since it flows into the floating oil recovery means and is separated, it is possible to provide a filtering device suitable even when only the oil emulsion liquid is used.

Further, for example, by connecting the bypass route from the inlet side of the membrane-utilizing type filtering means to the outlet side of the membrane-utilizing type filtering means or the supply route, the bypass route is connected from the high pressure side to the low pressure side. As a result, a pump for flowing a high-concentration fluid to be filtered into the floating oil recovery means for oil-water separation is not required, so that the device configuration can be simplified.

Furthermore, by providing a flow rate control valve for controlling the flow rate of the fluid to be filtered in the bypass path and controlling the opening / closing amount of the valve, the oil / water separation efficiency of the floating oil recovery means is further improved, and under optimum conditions. Oil-water separation is performed.

Therefore, the oil concentration of the concentrated liquid decreases as it passes through the floating oil recovery means. Then, when the carry-in speed of the device and the oil discharge speed of the floating oil recovery means match, the oil content concentration of the concentrated liquid in the circulation path becomes steady.

As a result, the cross-flow type membrane-utilizing filtration means in the circulation path can be operated with a constant load, and the apparatus can be stabilized. Therefore, it is possible to prevent a decrease in the permeation flux of the membrane-utilizing type filtration means.

Furthermore, by providing the dust removing means in at least one of the above-mentioned routes, the dust that has entered the route is removed, and the membrane-utilizing type filtering means and the floating oil collecting means have filters. It can prevent things from clogging. This makes it possible to further stabilize the device.

[Brief description of drawings]

FIG. 1 is a diagram of a filtering device according to a first embodiment of the present invention.

FIG. 2 is a diagram of a filtering device according to a second embodiment of the present invention.

FIG. 3 is a diagram of a filtering device according to a third embodiment of the present invention.

FIG. 4 is a diagram of an example in which a filtering device according to a third embodiment of the present invention is implemented.

FIG. 5 is a diagram of a filtering device according to a fourth embodiment of the present invention.

FIG. 6 is a diagram of a filtering device according to a fifth embodiment of the present invention.

FIG. 7 is a diagram of a filtering device according to a sixth embodiment of the present invention.

FIG. 8 is a diagram of a filtration device according to a seventh embodiment of the present invention.

FIG. 9 is a diagram of a filtering device according to an eighth embodiment of the present invention.

FIG. 10 is a view of a filtration device of a conventional membrane-utilizing filtration means.

FIG. 11 is a diagram of conventional floating oil recovery means.

FIG. 12 is a view of a filtering device of Conventional Example 1.

FIG. 13 is an explanatory diagram of floating oil recovery means.

FIG. 14 is a diagram of a filtering device of Conventional Example 2.

FIG. 15 is a view of a filtering device of Conventional Example 3.

FIG. 16 is a diagram of a filtering device of Conventional Example 4.

[Explanation of symbols]

 1, 1a, 1b, 1A, 1B Bypass path 2 Floating oil recovery means 2a Discharge port 2b Coalescer filter 2c Retention tank 2d Float switch 2e Discharge pipe 2f valve 2g Tank 2h float switch 3 Flow control valve 4 Constant flow control valve 5, 8,10,20,26 Throttle valve 6,24,126 Primary pressure gauge 7,27,127 Secondary pressure gauge 9 Expansion joint 11 Pressure switch 12 Air vent path 13,28 to 32,35 Open / close valve 14,37 Reverse Stop valve 15,16,21 Solenoid valve 17 Buffer tank 18 Pressure gauge 19,25 Valve 22 Bypass piping 23 Wind filter unit 23 'Wind filter (dust removing means) 33 units 34 Float switch 36,39,40 Strainer (dust removing means) 38 Pressure pump 101 cleaning 102 Ultrasonic Oscillator 103 Supply Path 103a Connection Part 113 Flow Control Valve 121 Pump 122 Membrane Utilizing Filtration Means 122a Outlet Side 122b Inlet Side 123 Hollow Fiber Membrane Module (Membrane Utilizing Filtration Means) 124 Hollow Fiber Membrane 125 Flow Control Valve 131 Return Path 132 Backwash valve A1, A2, A3, A4, A5 Arrow K1 Circulation path S1 Filtration device

Claims (4)

[Claims] 1. A cross-flow type membrane-utilizing filtration means, a circulation path for unidirectionally circulating a fluid to be filtered mixed with oil and water in the membrane-utilizing filtration means, and a fluid to be filtered which is connected to the circulation path. A supply path for supplying, a floating oil recovery means for separating and recovering an oil component of the fluid to be filtered concentrated in the circulation path, and a fluid to be filtered concentrated from the circulation path into the floating oil recovery means. And a bypass path for connecting the low-concentration separated liquid from the floating oil recovery means so as to flow out to either one of the circulation path and the supply path. 2. The filtering device according to claim 1, wherein the bypass path is connected from a high pressure side to a low pressure side. 3. The filtering device according to claim 1, further comprising a flow rate control valve for controlling the flow rate of the fluid to be filtered which flows into the floating oil recovery means, in the bypass path. 4. The dust removing means is provided in at least one of the paths.
Or the filtration device according to 3.