JP2691119B2 - Pressurized oil-water separator using electrolysis - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to, for example, a closed pressurization type oil-water separator using an electrolysis method related to bilge treatment containing oil components generated in an engine room of a ship. It is intended to provide a means suitable for separating and removing oil components in waste water.

[0002]

2. Description of the Related Art Conventionally, in order to separate and remove oil content from oil-containing bilge water generated in an engine room of a ship, for example, a parallel plate or coalescer (coarse graining material) is used to separate the oil content and water from the gravity difference. Known are the gravity separation method for separating by oil, the filtration separation method for adsorbing oil content or filtering water from oil content, etc., and the wastewater treatment containing fine oil content by mechanical dispersion or mixing of a surfactant. In this case, the electrolytic levitation separation method is adopted.

As one of the electrolytic levitation separation methods, as described in the specification of Japanese Patent Application No. 4-51525 filed by the present inventors, the present inventors have While constant power is supplied to the electrodes made of aluminum alternately arranged at appropriate intervals, and the polarities of the anode and the cathode are converted at predetermined intervals, while preventing passivation by electrolytic treatment of the sacrificial electrodes. Proposed a flotation method in which tiny oil droplets in a bilge generated from a ship engine room are coagulated and adsorbed on the flocs produced.

However, since the oil-water separator for ships sucks the bilge accumulated at the bottom of the engine room and is installed near the bilge reservoir located under the draft, the oil-water separator is operated during operation of the oil-water separator. Since the back pressure and the pressure of the pipe resistance of the outboard drainage pipe act, a closed pressurization structure is required.

In the electrolysis method of this technique, the bilge accumulated at the bottom of the ship is supplied under pressure to the oil-water separator by the bilge pump, so that the bubbles in the bilge water become unsaturated and the bubbles produced by the electrolysis method are dissolved and absorbed. However, the floating force of the flocs containing oil is weakened, and the processing performance is deteriorated. This can be explained from Henry's law that the amount of dissolved gas increases in proportion to the applied pressure when the gas is melted under pressure.

[0006]

Therefore, in the present invention,
A sealed pressurized oil-water separator that uses the electrolysis method is equipped with means that can maintain stable treatment performance, and improves the separation efficiency when electrolytically treating oil-containing bilge water at the ship bottom and discharging it out of the ship. This is intended to be achieved.

[0007]

In order to achieve the above-mentioned object, the present invention provides a closed pressurized oil-water separator by an electrolytic method, which comprises a separation tank for roughly or finely separating oil, an electrolytic tank, and a floating separation tank. In the above, an air dissolver for supplying compressed air and a pressure reducing valve are installed between the separation tank and the electrolytic cell.

Further, the present invention is a closed pressurized oil-water separator by an electrolysis method, comprising a separation tank for roughly or finely separating oil, an electrolysis tank, and a flotation separation tank, and between the separation tank and the electrolysis tank. Is characterized in that a pressure reducing valve and a bubble dissolver equipped with a non-eluting electrode for generating bubbles by electrolysis are installed.

[0009]

With the structure of the present invention, the bilge containing bubbles in a supersaturated state is introduced into the electrolytic cell by arranging the means for compensating for the insufficient bubbles consumed by pressurization and the pressure reducing means on the inlet side of the electrolytic cell. Therefore, not only the bubbles generated in the electrolytic cell can be prevented from being dissolved, but also the flocs are promoted to float by the bubbles deposited by the reduced pressure, and the oil-water separation performance can be stably maintained with high efficiency. Also,
The deposited bubbles clean the surface of each electrode and are generated by electrolysis, and can suppress the adhesion of scales that are resistant to the electrolytic current.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 1 is a first separation plate tank, and in this first separation plate tank 1, a plurality of substantially parallel separation plates 2 are arranged in parallel, and on the side wall of the first separation plate tank 1. Is provided with a supply pipe 4 for sucking the oil-containing bilge generated from the engine room of the ship by the oil-water supply pump 3 and supplying it under pressure into the first separation plate tank 1. Then, in the oil-containing bilge that is sucked by the oil / water supply pump 3 and is pressurized and supplied into the first separation plate tank 1 through the supply pipe 4, the separation plate 2 roughly separates the oil component, and the separated oil is first separated. It is stored in the upper part of the plate tank 1.

An oil level detector 5 is provided on one side of the upper part of the first separation plate tank 1 in which the separated oil is stored, and the oil level detector 5 allows the oil accumulated in the first separation plate tank 1 to be collected. The position of the surface is detected. Similarly, on the other side of the upper part of the first separating plate tank 1,
An oil drain pipe 6a connected to the oil drain valve 6 is provided, and when the position of the oil level accumulated in the first separation plate tank 1 reaches a predetermined height, a signal from the oil level detector 5 causes The oil valve 6 is automatically opened, and the oil is discharged to the outside of the first separation plate tank 1 by the oil discharge pipe 6a.

A second separation tank 7 is provided at the subsequent stage of the separation plate 2 of the first separation plate tank 1, and a coalescer (coarseening material) 8 is housed in the second separation tank 7 for the first separation. The bilge roughly separated by the plate tank 1 is finely separated by a coalescer (coarseening material) 8. An oil level detector 9 is provided on one side of the upper part of the second separation tank 7, and the position of the oil level accumulated in the second separation plate tank 7 is detected by this oil level detector 9. Similarly, an oil drain pipe 10a connected to the oil drain valve 10 is provided on the other side of the upper portion of the second separation plate tank 7, and the position of the oil surface accumulated in the second separation plate tank 7 is at a predetermined height. Oil level detector 9
The oil discharge valve 10 is automatically opened in response to a signal from the oil, and oil is discharged to the outside of the second separation plate tank 7 by the oil discharge pipe 10a.

An air dissolver 12 and a pressure reducing valve are provided via a check valve 11 between the communication hole 1a formed below the second separation plate tank 7 and the transfer pipe 17 connected to the electrolytic cell 18. 17 and 17 are arranged. The air dissolver 11 includes an air diffuser 1
5 is installed, and compressed air from the compressor 13 receives the check valve 14
Is supplied to the air diffusing tube 15 via the. Therefore, the bilge supplied to the air dissolver 12 through the communication hole 1a of the second separation plate tank 7 is in a state of containing sufficient air. Excess air is released to the atmosphere via the automatic air valve 16.

In the air dissolver 12, the bilge in which the air has been sufficiently dissolved is decompressed by the decompression valve 18 and transferred to the transfer pipe 18.
Is supplied to the electrolytic bath 19. In this electrolytic cell 19, an anode plate 20 and a cathode plate 21 made of a plurality of aluminum sheets are juxtaposed at appropriate intervals. This anode plate 20,
A direct current power supply device 22 arranged outside the electrolytic cell 19 is connected to the cathode plate 21. Therefore, in the electrolytic cell 19, the direct current from the power supply device 22 is applied to the anode plate 20,
By flowing to the cathode plate 21, aluminum hydroxide and bubbles (H ₂ ) are generated, and the bilge that has been finely separated in the second separation tank 7 and sufficiently dissolved air undergoes defoaming and aggregation reactions, Aluminum hydroxide containing oil [Al
Floc of (OH) ₃ ] is generated.

The aluminum hydroxide flocs and bubbles sufficiently contact the bilge in the mixing tube 23 provided between the electrolytic cell 19 and the flotation / separation tank 24. And
The flocs that have been easily floated and separated by adsorbing air bubbles are the flotation separation tanks 2 arranged above the first separation plate tank 1.
3, the fine oil droplets in the oil-containing wastewater in the bilge are aggregated, adsorbed and floated and separated.

In the floating separation tank 24, an outboard discharge pipe 25 for discharging the bilge from which oil has been separated and removed to the outside of the floating separation tank 24,
A flock surface detector 26 for detecting the flock surface in the floating separation tank 24, and above the flock surface detector 26,
A flock discharge pipe 27a provided with a flock discharge valve 27 for automatically opening and discharging the flock in the flotation tank 24 to the outside by the operation of the flock surface detector 26.
And an automatic air bleeding valve 28 provided on the upper part thereof. The automatic air bleeding valve 28 is for automatically releasing gas such as air or hydrogen gas accumulated in the floating separation tank 24 to the atmosphere.

In the above-described structure of the present invention, the bilge containing the oil discharged from the engine in the ship is pressurized and supplied into the first separation tank 1 by the pump 3 through the supply pipe 4.
The crude oil is separated by the separation plates 2 arranged side by side substantially in parallel. The bilge from which the crude oil has been separated flows into the second separation tank 7 and is finely separated by the coalescer 8 provided in the second separation tank 7.

When electrolysis is performed in a pressurized state, the generated bubbles have a small particle size and a small amount, and as a result, the floc levitation force decreases and the separation efficiency deteriorates.
It is considered that this is because bubbles generated by electrolysis are compressed and dissolved at the same time.

In the present invention, in order to prevent such a phenomenon, the bilge fed into the air dissolver 12 provided between the second separation tank 7 and the electrolytic tank 19 is the compressor 1
A large amount of air supplied from No. 3 is melted into a saturated state, and the air is sent to the electrolytic cell 19 through the transfer pipe 18 together with the bubbles that are supersaturated by the pressure reducing valve 17 and are deposited.

When the anode plate 20 and the cathode plate 21 provided in the electrolytic cell 19 are energized, the aluminum hydroxide flocs produced by electrolysis in the anode plate 20 aggregate the minute oil droplets contained in the bilge. Adsorb and remove oil. At this time, the bubbles in the bilge are supersaturated and deposited, and flow into the electrolytic cell 19, so that the bilge has a high electrolyte concentration,
Although the deposition rate of the scale generated by electrolysis is also fast, the surfaces of the anode plate 20 and the cathode plate 21 are cleaned by bubbling of a large amount of bubbles that are deposited due to the pressure reducing effect of the pressure reducing valve 17, and an increase in the electrical resistance value is prevented. .

Meanwhile, in the electrolytic cell 19, bubbles of aluminum electrolytic reaction (H ₂₎ is also produced, during bilge, since the air bubbles are contained in a large amount, bubbles under pressurized state (H ₂₎ Does not dissolve, but adheres oil to the flocs of electrolytically produced aluminum hydroxide and contributes greatly to the action of increasing the levitation force.

The bilge and aluminum hydroxide flocs and bubbles electrolytically treated in the electrolytic bath 19 are mixed in the mixing pipe 23 and the floating separation bath 2 is used.
4 flows into. The minute oil droplets in the bilge are aggregated / float-separated by the action of aluminum hydroxide and bubbles, and are accumulated in the upper part of the flotation / separation tank 24. On the other hand, the bilge from which oil has been separated and removed passes through the outboard discharge pipe 25 and is discharged to the outside of the ship.

The flocs accumulated in the upper portion of the flotation tank 24 are detected by the floc surface detector 26, and the floc discharge valve 27 is operated to be discharged by the floc discharge pipe 27a.

FIG. 2 shows another embodiment of air dissolution as a means for improving the electrolytic floating separation efficiency under pressure and as a means for compensating for insufficient bubbles in place of the air dissolver. In this embodiment, a bubble dissolving tank 29 is provided between the second separation tank 7 and the electrolytic tank 19 via the check valve 11, and the bubble dissolving tank 29 has a non-eluting electrode 30, 31
And a DC power source 32 are arranged, electrolysis is performed, and the pressure is reduced by the pressure reducing valve 17 to generate a large amount of bubbles.

[0025]

In the structure of the present invention, by disposing the air dissolving means and the pressure reducing valve on the inlet side of the electrolytic cell, bilge containing a large amount of bubbles can be supplied to the electrolytic cell.
Bubbles are not deposited in the electrolytic cell, and the bubbles due to electrolysis are not dissolved, which has the effect of improving the floc levitation force and increasing the separation efficiency. By bubbling a large amount of the deposited bubbles, the anode plate, the cathode The surface of the plate is cleaned, which has the effect of preventing an increase in the electric resistance value.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an embodiment of an oil / water separator according to the present invention.

FIG. 2 is a configuration diagram showing another example of the bubble dissolving means in the oil-water separator of the present invention.

[Explanation of symbols]

 1 First Separation Tank 2 Multiple Separation Plates 7 Second Separation Tank 8 Coalescer 9 Oil Level Detector 12 Air Dissolver 13 Compressor 15 Diffuser Pipe 17 Pressure Reduction Valve 18 Transfer Pipe 19 Electrolytic Tank 20 Anode Plate 21 Cathode Plate 22 DC Power supply device 23 Mixing pipe 24 Floating separation tank 25 Outboard discharge pipe 26 Flock surface detector 27 Flock discharge valve 29 Bubble dissolving tank 30 Non-eluting electrode 31 Non-eluting electrode 32 DC power supply device

Claims (2)

(57) [Claims] 1. A closed pressurized oil-water separator by an electrolysis method comprising a separation tank for roughly or finely separating oil, an electrolysis tank, and a flotation separation tank, wherein compressed air is provided between the separation tank and the electrolysis tank. A pressure type oil-water separator using an electrolysis method, which is provided with an air dissolver for supplying air and a pressure reducing valve. 2. A closed pressurized oil-water separator by an electrolysis method comprising a separation tank for roughly or finely separating oil, an electrolysis tank, and a flotation separation tank, wherein electrolysis is performed between the separation tank and the electrolysis tank. A pressure type oil-water separator using an electrolysis method, which is characterized in that a bubble dissolver having a non-eluting electrode for generating bubbles is installed and a pressure reducing valve.