JP4072334B2 - Oil / water separator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an oil / water separator that separates oil and water from a mixed liquid of oil and water, such as a compressor drain, and more particularly to an oil / water separator using a floating separation method using fine air bubbles.
[0002]
[Prior art]
The conventional oil-water separation by the flotation separation method is described in JP-A-5-317847. In this method, the stock solution is pumped up from a large-capacity liquid tank, and after pressurizing, the compressed air is mixed and dissolved, and after excess air is removed, the air is injected into the liquid tank to be treated and reduced in pressure to reduce fine air bubbles. Is generated. And when this fine air bubble adheres to an oil component, an oil component floats in water and can isolate | separate oil and a water | moisture content.
[0003]
[Problems to be solved by the invention]
When the flow rate to circulate in order to dissolve the air in the liquid to be treated is small relative to the volume of the liquid tank to be treated, the oil / water separation rate, that is, the oil concentration lowering rate is slow by this method, but the oil concentration gradually decreases.
[0004]
However, when the processing target is a compressor drain, the amount of liquid to be processed is small because the liquid to be processed is discharged little by little. Moreover, the installation area of the oil-water separator itself is limited. For this reason, it is desired to reduce the size of the liquid tank to be processed. And if the size is simply reduced, the circulating flow in the liquid tank to be treated becomes strong, and the oil particles that have floated up to the upper surface of the liquid ride down the water and descend to the vicinity of the bottom of the liquid tank to be treated. Despite the large circulation flow rate, that is, the fine bubble flow rate, the oil concentration does not fall below a certain value, and the oil / water separation performance deteriorates.
[0005]
The present invention provides an oil / water separator capable of high-speed processing up to a low oil concentration even in a small liquid tank to be treated, that is, an oil / water separator, in view of the current state of the oil / water separation method using the floating separation method as described above. [0006]
[Means for Solving the Problems]
In order to achieve the above object, in the present invention, a partition plate for dividing the liquid tank to be treated into two parts in the vertical direction is arranged, the lower part is a fine bubble generating part, the upper part is an oil-water separation part, and a large amount in the lower part. A large amount of treated liquid is circulated in order to generate fine bubbles, so that this circulating flow does not generate a circulating flow in the upper part which is the oil-water separator, and the fine bubbles generated in the lower part pass through this partition plate. A plurality of holes are provided.
Therefore, the upper part is in a state where fine bubbles continuously float. By continuously supplying the stock solution to be treated into this, fine bubbles adhere to and float on the oil. Since only the treated liquid is collected in the lower part of the liquid tank to be treated, oil and water can be separated continuously by discharging the same flow rate as the raw liquid supply flow rate from the lower part.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
One embodiment of the present invention is shown in FIG. The liquid tank section to be processed includes the liquid tank 11 to be processed, and includes a separation section 80 and an oil collection section 83 that are divided by the partition wall 12. Further, the liquid tank 11 to be treated is provided with a large bubble separator 13 so as to communicate with the separation unit 80. A large bubble discharge pipe 14 is connected to an upper portion of the large bubble separator 13 near the opening on the separation unit 80 side, and the large bubble discharge pipe 14 is located in the separation unit 80 from the vicinity of the intermediate portion in the height direction of the liquid tank 11 to be treated. The end portion of the liquid to be processed is opened near the upper surface. Further, a partition plate 15 is provided at an intermediate portion in the height direction of the separation portion 80, and the separation portion 80 is divided into an upper portion 82 and a lower portion 81 by the partition plate 15. The partition plate 15 is formed of a punching board having a large number of circular holes or a metal net, and the total area of the holes with respect to the area of the separating portion is about 15% to 80%.
[0008]
In addition, a supply pipe 23 that constitutes a process liquid supply unit is connected to a predetermined height position outside the liquid tank 11 to be processed (above the partition plate 15: on the upper part 82 side), and a valve is connected to the supply pipe 23. A first pump 21 is provided via 22. Further, outside the liquid tank 11 to be treated, a pipe 30 constituting a liquid circulation part to be treated is connected to the second pump 31 via a valve 36, and a valve 32 provided on the output side pipe 37 of the second pump 31. Is connected to a nozzle 33 provided in the large bubble separator 13. Further, an air supply pipe 35 for supplying air is connected to the pipe 30 via a valve 34. Further, a drain pipe 41 for draining the separated water is provided at the bottom of the separation section 80, and an oil drain pipe 51 for discharging the oil is provided at the bottom of the oil collection section 83.
[0009]
Next, the operation will be described.
First, the second pump 31 is operated in a state where the upper part 82 and the lower part 81 of the separation part 80 of the liquid tank 11 to be treated are filled with fresh water or a treated liquid. At this time, the valve 36, the valve 34, and the valve 32 are open. At this time, the fresh water or processed liquid from the valve 36 flows through the pipe 30, whereby the air supply pipe 35 side becomes negative pressure, and the dissolving air flows from the air supply pipe 35. The inflowing air is mixed and dissolved in the liquid flowing in the pipe 30. The excess air that has not been dissolved is discharged from the nozzle 33 into the large bubble separator 13 together with the liquid in which the air has been dissolved. The liquid and air to which pressure has been applied by discharging from the nozzle 33 are decompressed, the air dissolved in water becomes fine bubbles, and the undissolved air becomes large bubbles.
[0010]
Since the large bubble separator 13 has a characteristic that the rising speed in liquid increases as the bubble diameter increases, the large bubbles accumulate on the upper portion of the large bubble separator, and the upper portion 82 of the separation unit 80 from the large bubble discharge pipe 14. It is discharged above. In addition, if the ceiling part of the large bubble separator 13 is provided with an inclination so that bubbles are easily collected in the large bubble discharge pipe, the effect of separating large bubbles is further increased. Further, it is possible to prevent a large bubble from flowing out to the separation portion side by providing a protruding portion or a baffle plate or the like on the ceiling portion side on the large bubble separator outlet side.
[0011]
Accordingly, water containing only fine bubbles is ejected from the outlet (opening) of the large bubble separator 13 to the separation unit 80. The water ejected from the opening is mixed with the water present in the lower part 81 of the separation part 80 and flows while decelerating. The flow forms a circulating flow as shown in FIG. 2, and a downward flow 91 from above is formed particularly near the outlet of the large bubble separator 13. When a large amount of water in the upper part 82 is mixed with the downward flow 91, the oil / water separation performance is lowered. For this reason, a partition plate 15 (for example, a punching board or a wire net having a large number of circular holes) that prevents mixing with the downward flow 91 and allows the passage of fine bubbles is provided, and the lower portion 81 is formed as a fine bubble generating portion. As independent. This partition plate 15 also has an effect of preventing large bubbles from flowing out to the upper portion 82 side.
[0012]
Further, since the processing liquid and the processed liquid are separated by the partition plate 15 and the processed liquid in the partitioned lower portion 81 is circulated, the oil is separated and processed, so that the nozzle or the like The oil does not adhere and become clogged, and the separation performance can be maintained for a long time.
[0013]
In the upper part 82, a large amount of fine bubbles rising through the partition plate 15 are rising. In this state, the valve 22 is opened and the pump 21 is driven to supply the liquid to be processed into the upper part 82 of the separation part 80. Then, fine bubbles adhere to and float on the oil in the liquid to be treated, and the oil can be separated. Although the supply amount of fine bubbles is proportional to the flow rate of the liquid to be treated, the flow rate of circulating water is determined considering that the normal working pressure of circulating water is 0.3 to 0.8 MPa and the amount of dissolved air is proportional to pressure. 30 to 100 times the flow rate of the liquid to be treated.
[0014]
Accordingly, it is possible to suppress the generation of a circulating flow in the upper portion 82 of the liquid to be processed by supplying the liquid to be processed, and the entire liquid is almost stationary and suitable for oil-water separation. When the supply of the liquid to be processed is started, the processed surplus water is discharged from the drain pipe 41 provided at the bottom of the separation unit 80 of the liquid tank 11 to be processed. Since this drain pipe 41 is set so as to lift the drainage to a height substantially equal to the maximum liquid level of the liquid to be treated in the liquid tank to be treated, it is possible to drain the excess water naturally.
[0015]
In addition, the provision of the partition plate 15 makes it difficult for the liquid in the upper part 82 and the lower part 81 to be mixed, and the liquid to be treated is continuously supplied, which affects the overall flow. The processed liquid can be discharged from the bottom of the liquid tank 11 to be processed through the drain pipe 41, and continuous processing is possible. Further, by making the middle part of the drain pipe 41 the same as the liquid surface 61 to be processed, it is possible to continuously discharge the same flow rate as the liquid supply amount to be processed without special control.
[0016]
The floated oil 62 that has been floated and separated is deposited on the liquid surface 61 to be treated. When the floated oil 62 becomes higher than the partition wall 12, it overflows, falls to the oil collecting section 83, collects at the bottom, and is discharged from the oil discharge pipe 51. .
[0017]
Depending on the shape and dimensions of the lower portion 81, the partition plate 15 may exhibit a necessary function even if it has a shape in which only the central portion is opened.
[0018]
In addition, the present invention exhibits necessary functions even when the air supply method for the microbubble generator and the large bubble separator structure are different methods.
[0019]
【The invention's effect】
According to the present invention, the liquid tank to be treated can be reduced in size, and oil / water can be continuously separated down to a low oil concentration, that is, an oil concentration that can be discharged directly to a drainage channel.
[Brief description of the drawings]
FIG. 1 is an overall system diagram of the present invention.
FIG. 2 is a flow diagram in the liquid tank to be treated according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 ... Liquid tank to be treated, 15 ... Partition plate, 21 ... First pump, 23 ... Supply pipe, 31 ... Second pump, 33 ... Nozzle, 41 ... Drain pipe, 51 ... Oil discharge pipe

Claims (2)

In an apparatus that supplies air into the liquid to be treated to float and separate the oil,
The liquid to be processed in the liquid tank to be processed or the liquid to be processed is pumped to mix and circulate the liquid to be processed, and the air discharged from the nozzle provided in the liquid to be processed is mixed. A large bubble removal unit that removes large bubbles from the liquid, a separation unit that separates oil using micro bubbles, and a collection that separates and floats on the liquid surface to be treated and collects the oil beyond the partition wall. With an oil part,
An oil-water separator according to claim 1, wherein the separation part is divided into an upper part and a lower part by a partition plate having a plurality of holes, and a supply part for supplying a liquid to be treated is provided on the upper part side. In an apparatus that supplies air into the liquid to be treated to float and separate the oil,
The liquid to be processed in the liquid tank to be processed or the liquid to be processed is pumped to mix and circulate the liquid to be processed, and the air discharged from the nozzle provided in the liquid to be processed is mixed. A large bubble removal unit that removes large bubbles from the liquid, a separation unit that separates oil using micro bubbles, and a collection that separates and floats on the liquid surface to be treated and collects the oil beyond the partition wall. With an oil part,
The divided separation portion in the upper part and the lower part by a partition plate having a plurality of holes, which both generates a circulating flow in the lower side, large bubbles could not be removed in the previous SL large bubble removing unit on the upper side An oil-water separator characterized in that the upper part is configured not to leak.

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