JPH0148076B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an oil recovery device in a settling tank.

In order to prevent environmental pollution, tank wash water from an oil tanker is once introduced into a settling tank, and then separated by gravity into floating oil and an oil-water mixture within the tank. This oil-water mixture is then led to an oil-water separator where it is forcibly separated into oil and water for treatment, but since the floating oil has a relatively high oil content, it is not passed directly through the oil-water separator, but instead is treated using another method. We are trying to collect and process it.

FIG. 1 shows a conventional floating oil recovery device. In the figure, 1 is a settling tank, and 2 and 3 are floating oil and an oil-water mixture separated by gravity in the settling tank 1, respectively. Reference numeral 4 denotes a float having a specific gravity intermediate between that of the floating oil 2 and the oil-water mixture 3, and a suction port 4a provided on the float 4 is always open into the layer of the floating oil 2. 5 is a flexible hose, one end of which communicates with the suction port 4a of the float 4, and the other end connected to a discharge pipe 6 provided in the tank surrounding wall 1a. 7 is a pump, and 8 is a valve.

Although a means for discharging the oil-water mixture 3 is not shown in FIG. 1, a conventional pump means may be sufficient as this.

According to the configuration of the conventional device described above, only the floating oil 2 in the settling tank 1 can be collected from the suction port 4a of the float 4 through the flexible hose 5 and the discharge pipe 6, and the level of the floating oil 2 can be Even if the floating oil 2 fluctuates, the flexible hose 5 expands and contracts accordingly, so that it can be recovered regardless of the level of the floating oil 2.

However, with the above configuration, there is no problem when the settling tank is installed on land, but there are many cases where it is installed on a barge, and in such cases, the float 4 may be damaged by the movement of the settling tank and the tank inner wall. The drawback was that they collided violently with each other, often resulting in breakdowns.

The present invention has been made to solve the above-mentioned drawbacks, and instead of using the float-type suction method that is affected by the fluctuation of the settling tank as described above, it uses the siphon principle to reduce the amount of water inside the settling tank. The present invention aims to provide an efficient oil recovery device that does not cause failures as an oil recovery system.

The oil recovery device in a settling tank according to the present invention includes a tank that separates oil and water by gravity, an inverted U-shaped siphon pipe provided in the tank and having a valve and a pump on the discharge side, and a siphon pipe of the siphon pipe. An atmosphere communication pipe connected to the top, a floating oil suction port opened in the side wall of the tank at a position approximately at the same level as the top of the siphon pipe, and a valve connected between the floating oil suction port and the pump. a floating oil discharge pipe connected thereto, and means for detecting that the pump starts sucking air from the atmospheric communication pipe or the floating oil suction port and switching the opening and closing of the valve of the siphon pipe and the valve of the floating oil discharge pipe; It is characterized in that the internal apex of the siphon pipe and the lower lip of the floating oil suction port are located at the same level.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 is an explanatory view showing one embodiment of the present invention, and FIG. 3 is an enlarged detailed view of section A in FIG. In these figures, 1 is a settling tank;
In this embodiment, the inside of the tank 1 is further divided by a partition wall 10 into a primary separation tank 11 and a secondary separation tank 12. Reference numeral 13 denotes an introduction pipe for introducing tank washing water, which is water to be treated, into the primary separation tank 11. 14
In order to introduce the relatively oil-rich treated water in the primary separation tank 11 into the secondary separation tank 12, both separation tanks 11,
12, one end of which is in the primary separation tank 11, and one end of which is in the primary separation tank 11
It opens in the shape of a flap near the separation surface of the floating oil 2a separated by gravity inside. The other end opens to the lower part of the secondary separation tank 12 via a valve 15-8. 16 is a siphon pipe provided in the secondary separation tank 12, and a valve 15-1 and a pump 7 are provided on the discharge side of the siphon pipe. 17 is a filter provided at the suction end of the siphon pipe 16. Atmospheric communication pipe 1 is installed at the top 16a of the siphon pipe 16, which is bent into an inverted U shape.
8 are connected, and the atmosphere communication pipe 18 is provided with a valve 15-7. 19 is the top 1 of the siphon pipe 16
This is a floating oil suction port opened in the side wall 12a of the secondary separation tank 12 at a position substantially on the same level as 6a. 20 is a valve that opens and closes the floating oil suction port 19 and whose opening degree can be adjusted. The lower lip of this valve 20 is positioned at the same level as the inner top 6b of the top 6a of the siphon tube 16 (see FIG. 3).
The floating oil 2b separated by gravity in the secondary separation tank 12 is always located above this level 21. Note that the separation surface 22 of the floating oil 2b is at the same level as the level 21 or slightly below it in the state shown in FIG. 23 is a floating oil discharge pipe connected to the floating oil suction port 19 at one end and to the suction side of the pump 7 at the other end. The floating oil discharge pipe 23 has a valve 15.
-3 is provided. Reference numeral 24 denotes an oil-water mixed liquid discharge pipe that communicates between the lower part of the primary separation tank 11 and the suction side of the pump 7, and includes a filter 25 and a valve 15-1.

On the discharge side of the pump 7, there is an oil/water mixture inlet pipe 27 for introducing the oil/water mixture into the oil/water separator 26 via a valve 15-2, and an oil/water mixture inlet pipe 27 for introducing the oil/water mixture into the oil/water separator 26 via a valve 15-4.
8 is provided with a floating oil introduction pipe 29 through which floating oil is introduced. Reference numeral 30 denotes a circulation introduction pipe for circulating and reprocessing the water to be treated in the secondary separation tank 12 as needed, and is equipped with a valve 15-6. 31 is a drain pipe for separated water forcibly separated by the oil-water separator 26, and a valve 32
In this embodiment, the drain port 34 of the barge 33
has been contacted. Reference numeral 35 denotes a drain pipe for the separated oil that has been forcibly separated by the oil-water separator 26, and is equipped with a valve 36 and connected to the oil tank 28. 37 is a level switch provided in the secondary separation tank 12.

The present embodiment is constructed as described above, and its operation will be explained next.

First, the oil tanker's tank cleaning water is supplied to the inlet pipe 13.
The oil is once introduced into the primary separation tank 11 through the separation tank 11, where it is separated by gravity into the floating oil 2 and the oil-water mixture 3. Next, the valve 15-8 of the primary separation introduction pipe 14 is opened to introduce the relatively oily water to be treated in the primary separation tank 11 into the secondary separation tank 12. At this time, the valve 15-7 of the atmosphere communication pipe 18 is also kept open. When this water to be treated is introduced to the position shown by the broken line in FIG. 2, the valve 15-8 is closed and the water is separated by gravity as in the case of the primary separation tank 11. In this case, the secondary separation tank 12
The thickness of the floating oil 2b separated in the primary separation tank 1
This becomes larger than that of the floating oil 2a in 1, and henceforth, the floating oil 2b can be discharged more efficiently as will be described later.

The oil/water mixed liquids 3a and 3b with relatively low oil content in the primary separation tank 11 and the secondary separation tank 12 are separated by a valve 15-.
After opening 1, 15-5 and 15-2, pump 7
When activated, the oil is introduced into the oil-water separator 26 through the siphon pipe 16 and the oil-water mixture discharge pipe 24, and further through the common oil-water mixture introduction pipe 27. The separated water, that is, the treated water forcibly separated by the oil-water separator 26, is then drained into the drain pipe 3 by opening the valve 32.
The separated oil is discharged into the seawater from the drain port 34 of No. 1, and the separated oil is discharged into the oil tank 2 through the discharge pipe 35 by opening the valve 36.
It will be collected within 8 days.

As the oil-water mixture 3b in the secondary separation tank 12 is discharged and treated as described above, the separation surface 2
2 gradually decreases. When the separation surface 22 reaches the inner top 16b of the top 16a of the siphon pipe 16, the pump 7 will suck air through the atmosphere communication pipe 18. Therefore, the descending of the floating oil 2b and the oil-water mixture 3b in the secondary separation tank 12 stops at the level 21 and does not descend any further, and upon sensing the air suction by the pump 7, the valve 15-
1, 15-5 and 15-2 are closed, and one-way valve 15-
3 and 15-4 open. And floating oil suction port 19
When the valve 20 is opened by adjusting the opening degree, the floating oil suction port 1 is opened.
9, the floating oil 2b in the secondary separation tank 12 is transferred to the floating oil discharge pipe 23 and the floating oil inlet pipe 2.
9 and can be collected in the oil tank 28. In this case, since the floating oil 2b is thick as described above, the floating oil 2b with a high concentration can be efficiently recovered. Then, when the pump 7 starts sucking air, the valves 15-3 and 15 simultaneously
-4 is closed, and conversely valves 15-1, 15-5 and 15
-2 is opened and the above operation is repeated. Note that the oil/water mixture 3a in the primary separation tank 11 is discharged through the oil/water mixture discharge pipe 24 and the circulation introduction pipe 30.
The oil may then be introduced into the separation tank 12 for reprocessing and then passed through the oil/water separator 26.

In the present invention, it is not necessary to divide the settling tank into primary and secondary separation tanks as in the above embodiment, but oil can be recovered more effectively if this is done.

As explained above, according to the present invention, the water to be treated introduced into the settling tank can be systematically separated into oil and water by applying the siphon principle. It is constructed with piping, and there are no components in the tank that can cause failures, such as floats or level switches, which are constantly subject to the agitation of oil and water, so it is possible to drastically reduce failures due to agitation of the tank.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a conventional oil recovery device, FIG. 2 is an explanatory diagram showing an embodiment according to the present invention, and FIG. 3 is an enlarged detailed view of section A in FIG. 1: Tank, 7: Pump, 15-1, 15-
5: Valve, 16: Siphon pipe, 18: Atmospheric communication pipe,
19: Floating oil suction port, 23: Floating oil discharge pipe.

Claims (1)

[Claims] 1. A tank that separates oil and water by gravity, an inverted U-shaped siphon pipe provided in the tank with a valve and a pump on the discharge side, an atmosphere communication pipe connected to the top of the siphon pipe, and the siphon. a floating oil suction port opened in the side wall of the tank at a position approximately at the same level as the top of the pipe; a floating oil discharge pipe connecting the floating oil suction port and the pump via a valve; means for detecting that air has started to be sucked in from the atmosphere communication pipe or the floating oil suction port and switching the opening and closing of the valve of the siphon pipe and the valve of the floating oil discharge pipe, the internal apex of the siphon pipe and the floating oil An oil recovery device in a settling tank, characterized in that the lower lip of the oil suction port is located at the same level.