JP2003118681A - Residual oil treating method and device for oil tanker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily and inexpensively treat oil remaining in a tank chamber 13 while reducing a load to environment. SOLUTION: Electricity is applied between a positive plate and a negative plate contacting seawater 14 filled in the tank chamber 13 of the oil tanker 11, the seawater 14 is electrolyzed, sodium hydroxide is produced, and the oil remaining in the tank chamber 13 is saponified. By this, the residual oil is changed to soap having little load to the environment, and as a result, pollution of a nearby sea area is suppressed even when the sea water is discharged as it is.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for treating oil remaining after oil is extracted from an oil tanker.

[0002]

2. Description of the Related Art Generally, an oil tanker is used for transporting oil such as crude oil and heavy oil to a destination, and after such oil is taken out from the tank chamber at the destination, the water line is normally positioned. Seawater is injected as ballast water into the empty tank chamber to lower the temperature to the point where the seawater is sailed to the oil loading port, and then the seawater (ballast water) is discharged from the tank chamber near the loading port. Oil is loaded in the empty tank chamber.

Here, even if the oil is extracted from the tank chamber as described above, a small amount of oil remains on the inner surface of the tank chamber. Therefore, when seawater (ballast water) is injected into the tank chamber, the seawater is discharged. However, if seawater containing such oil is loaded and discharged near the port, there is a problem that the nearby sea area will be contaminated with oil.

In order to solve such a problem, conventionally, the dispersant is sprinkled on the seawater in the tank chamber to emulsify and disperse it, or the seawater in the tank chamber is sent to a filter by a pump, and the oil is filtered by the filter. Are separated and collected from seawater.

[0005]

However, the former method requires a large amount of the oil treatment agent, which is 20 to 50% of the oil, and is expensive, and the oil treatment agent itself is toxic. There is a problem. On the other hand, in the latter method, the filter is clogged with oil in a short time, so that the filter must be replaced frequently, resulting in an increase in cost and a decrease in work efficiency.

An object of the present invention is to provide a residual oil treatment method and device for an oil tanker, which can treat residual oil easily and inexpensively while reducing the load on the environment.

[0007]

[Means for Solving the Problems]
In addition, the process of injecting seawater as ballast water into the empty tank chamber of the oil tanker from which oil has been extracted, and energizing between the anode and the cathode that are in contact with the seawater in the tank chamber during the navigation of the oil tanker. By electrolyzing the seawater to produce sodium hydroxide, and saponifying the oil remaining in the tank chamber with the sodium hydroxide, by a residual oil treatment method for an oil tanker,

Secondly, between the anode and the cathode which are in contact with seawater injected as ballast water into the tank chamber of the oil tanker from which oil has been extracted, and between the anode and the cathode during the navigation of the oil tanker. Can be achieved by an oil tanker residual oil treatment device equipped with a power source for electrolyzing the seawater to electrolyze the seawater to generate sodium hydroxide and to saponify the oil remaining in the tank chamber with the sodium hydroxide. it can.

In the present invention, as described above, an electric current is applied between the anode and the cathode which are in contact with the seawater in the tank chamber, whereby the seawater is electrolyzed to produce sodium hydroxide and Sodium hydroxide is used to saponify the oil that remains in the tank chamber, which changes the residual oil into soap, which has a low impact on the environment. As a result, even if the seawater (ballast water) is discharged as it is, pollution of nearby sea areas will occur. Is suppressed. Since such soap has a surface-active effect, even if unsaponified oil remains, the oil is emulsified and the load on the environment is reduced.

Further, since the saponification work as described above is carried out while the oil tanker is in operation, the oil treatment work at the loading port becomes unnecessary, and such a saponification work is simply conducted by energizing between the positive and negative electrodes. Therefore, the processing can be performed at low cost. Then, such processing work can be easily performed by the device as described in claim 3.

Further, according to the second aspect, the oil can be sufficiently saponified while suppressing abnormal wear of the anode.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. 1, 2 and 3, 11 is an oil tanker for transporting oil such as crude oil and heavy oil,
The cargo compartment of the oil tanker 11 has a plurality of box-shaped tank compartments 13 partitioned by partition walls 12, and the oil to be transported is loaded into these tank compartments 13 at a loading port. The oil thus loaded is transported to the destination by the navigation of the oil tanker 11, then extracted from the tank chamber 13 and unloaded, but in this empty state, the waterline of the oil tanker 11 rises. Since the posture at the time of navigation becomes unstable due to passing, seawater 14 is injected as ballast water into the empty tank chamber 13 after the oil has been extracted by a predetermined amount, and the waterline is lowered to the normal position.

Reference numeral 17 denotes a plurality of treatment means installed on the bottom wall of the tank chamber 13 at a predetermined distance from each other, in other words, a plurality of treatment means submerged in the bottom portion of the seawater 14, and each treatment means 17 is not provided at the lower end portion. It has a plurality of electromagnets 19 embedded in a mold case 18 made of a magnetic material such as plastic. Each of these electromagnets 19 has a substantially inverted U-shaped iron core 20 in which both end faces in the axial direction are exposed at the lower end face of the mold case 18, and around the iron core 20 is a spiral exciting coil 21 over the entire length of the iron core 20. Is wrapped around.

A power cable 22 is connected to the exciting coil 21 of each processing means 17, and a direct current power source 23 installed in the machine room of the oil tanker 11 is connected to the power cable 22. And the power cable from the DC power supply 23
When the exciting coil 21 is energized through 22, each processing means 17
Both end surfaces of the iron core 20 in the axial direction are magnetic pole surfaces having opposite polarities, adsorb the bottom wall of the tank chamber 13, and are temporarily fixed to the bottom wall. As a result, the processing unit 17 is prevented from falling or moving.

The upper surface of the mold case 18 is a cage-shaped outer cover made of a non-conductive material such as plastic.
24 is fixed, and an anode plate 27 as an anode and a cathode plate 28 as a cathode whose both ends in the longitudinal direction are supported by a pair of holders 25, 26 made of a non-conductive material similar to the above in the outer cover 24. Is stored. Here, the anode and cathode plates 27, 28 are in the shape of a rectangular plate, are parallel to each other and are upright at a predetermined distance.

The anode and cathode plates 27 and 28 are both made of titanium metal coated with a platinum layer and are connected to the power cable 22. Then, during the navigation of the oil tanker 11, when the current is continuously or intermittently applied between the anode plate 27 and the cathode plate 28 for a required time, the seawater 14 in contact with the anode and cathode plates 27, 28, In particular, sodium chloride (NaCl) dissolved inside is electrolyzed, and hypochlorous acid (HClO) is generated on the side of the anode plate 27, while that of the cathode plate.
Sodium hydroxide (NaOH) and hydrogen gas are generated on the 28 side.

A cage-shaped outer cover 31 made of a non-conductive material such as plastic is fixed to the outer cover 24 on the cathode plate 28 side, and a DC motor 32 is provided in the outer cover 31.
A plurality of stirring blades 34 fixed to the output shaft 33 of are stored. The power cable 22 is connected to the DC motor 32 of each processing means 17. As a result, when the DC motor 32 is energized from the DC power source 23 through the power cable 22, the stirring blade 34 causes the output shaft 33 to rotate. Rotate with cathode plate
The sodium hydroxide generated on the 28 side is sent into the seawater 14 and dispersed in the seawater 14 almost uniformly.

The sodium hydroxide dispersed in the seawater 14 almost uniformly in this way adheres to the inner surface of the tank chamber 13 by a slight amount, or is peeled off from the inner surface of the tank chamber 13 and drops off from the seawater 14 underwater. Contacting residual oil floating on the water surface, reacting with these oils, and gradually saponifying the oils. This changes the residual oil into soap, which has a low impact on the environment.
When 11 arrives near the oil loading port, pollution of nearby waters will be suppressed even if the seawater 14 (ballast water) is discharged as it is.

When it is necessary to prevent the discharge of soap, the soap can be separated from the seawater 14 by passing the seawater 14 through a filter or the like when discharging the seawater 14 (ballast water). Since such soap has a surface-active action, even if unsaponified oil remains, the oil is emulsified and the load on the environment is further reduced.

The density of the electric current flowing between the anode and cathode plates 27 and 28 described above is determined by the seawater injected into each tank chamber 13.
It is determined by the amount of 14 and total energizing time, but the value is 0.
It is preferably in the range of 05 to 0.25 mA. The reason is that if the current density is less than 0.05 mA, the amount of sodium hydroxide produced is too small to sufficiently saponify the residual oil, while the current density is less than 0.25 mA. This is because if it exceeds, the wear of the anode plate 27 becomes severe and the anode plate 27 may have to be replaced during the navigation of the oil tanker 11. When the current density is high, heat is generated and the seawater 14 is heated,
During the navigation of the oil tanker 11, there is no problem because the seawater relatively flowing around the oil tanker 11 absorbs heat to cool the seawater 14.

Further, the sodium hydroxide and the hypochlorous acid produced as described above undergo a neutralization reaction while diffusing in the seawater 14 and change into sodium hypochlorite. Sodium also has a weak reaction, but is said to be able to saponify oil. On the other hand, hypochlorous acid generated on the anode plate 27 side has a strong bactericidal action, so
It is possible to kill the pathogenic bacteria, viruses, algae, etc. that are alive in the seawater 13 of 13 and prevent the pathogenic bacteria, etc. from spreading to various places.

The mold case 18, the electromagnet 19, the outer cover 24, the holders 25 and 26, the anode and cathode plates 27 and 28, the outer cover 31, the DC motor 32, and the stirring blades 34 as a whole are as follows.
The processing means constituting the processing means 17, and the plurality of processing means 17, the power cable 22, and the DC power supply 23 as a whole, saponify and process the oil remaining in the oil tanker 11.
Make up 35.

Reference numeral 38 denotes work lids replaced with the lids of the inspection ports 39 connected to the respective tank chambers 13. The work lids 38 penetrate the power cable 22 in a sealed state. Further, the discharge hose 40 penetrates through these work lids 38,
A discharge means 41 for sucking the hydrogen gas generated from the cathode plate 28 side and discharging it to the outside of the tank chamber 13 is connected to these discharge hoses 40. When the amount of hydrogen gas generated is small, instead of omitting the discharge hose 40 and discharge means 41 described above, a through hole is provided in the work lid 38, and hydrogen gas is discharged from the tank chamber 13 through the through hole. You can also do it.

Next, the operation of the embodiment of the present invention will be described. When the oil tanker 11 with the oil fully loaded in the tank chamber 13 arrives at the destination, the oil is extracted from each tank chamber 13 and landed. After that, a plurality of processing means are introduced through the inspection port 39 in the empty tank chamber 13.
17 are carried in and installed on the bottom wall of the tank chamber 13 at a predetermined distance from each other. At this time, the power cable 22 is connected to all the processing means 17, and the lid of the inspection port 39 is replaced with the work lid 38.

Here, when the oil is extracted as described above, the tank chambers 13 are emptied, so that the waterline of the oil tanker 11 rises, and it is impossible to navigate the sea as it is. For this reason, each empty tank chamber
A predetermined amount of seawater 14 is injected as ballast water into 13 and the waterline of the oil tanker 11 is lowered to the normal position. As a result, all the processing means 17 will be submerged in the bottom of the seawater 14.

In this state, the sea is sailed to the oil loading port, and during this sailing, each processing means 17 is energized from the DC power source 23 through the power cable 22 for a required time. As a result, the electromagnet 19 generates a magnetic force to adsorb the bottom wall of the tank chamber 13, and temporarily fixes the processing means 17 to the bottom wall. On the other hand, the anode / cathode plates 27, 28 electrolyze the seawater 14 in contact with the anode / cathode plates 27, 28 to oxidize hypochlorous acid on the anode plate 27 side and hydroxylate on the cathode plate 28 side. It produces sodium and hydrogen gas. The stirring blade 34 is rotated by the operation of the DC motor 32 to stir the surrounding seawater 14 and disperse the sodium hydroxide generated on the cathode plate 28 side into the seawater 14 almost uniformly.

At this time, sodium hydroxide reacts with the oil remaining in the seawater 14 by reacting, gradually saponifying these oils, that is, changing them into soap. Meanwhile, the anode plate 27
The hypochlorous acid generated on the side is also diffused in the seawater 14,
Since this hypochlorous acid has a strong bactericidal action, it kills pathogenic bacteria, viruses, algae, etc. that are alive in the seawater 14. Further, the hydrogen gas generated from the cathode plate 28 side collects between the water surface of the seawater 14 and the upper wall of the oil tanker 11, and such hydrogen gas is discharged to the outside of the tank chamber 13 by the discharge means 41 through the discharge hose 40. To be done. Incidentally, the anode, the cathode plate 27,
When the density of the current flowing between the two is high, chlorine gas may be generated from the anode plate 27 side, and such chlorine gas is also discharged to the outside of the tank chamber 13 in the same manner as described above.

If the polarities of the anode and cathode plates 27 and 28 are fixed, metal ions are attracted to and adhere to the surface of the cathode plate 27 to make it difficult for current to flow. It is preferable to reverse the polarities of the cathode plates 27 and 28. In this way, the metal adhering to the surface of the cathode plate 27 becomes ions and is released into the seawater 14, enabling continuous energization.

After that, when the oil tanker 11 arrives near the oil loading port, it discharges the seawater 14 (ballast water). At this time, however, the residual oil has changed to soap, which has a small impact on the environment. Even if the seawater 14 is discharged, pollution in the nearby sea area is suppressed. In addition, in order to prevent the above-described discharge of the soap, when the seawater 14 is discharged, the seawater 14 may be passed through a filter or the like to separate the soap.

In the above-described embodiment, both the anode (anode plate 27) and the cathode (cathode plate 28) are installed in the holder 26 of the processing means 17, but in the present invention, only the anode is installed, The cathode may be the bottom wall or partition of the tank chamber 13 of the oil tanker 11. In this case, it is necessary to remove oil from the inner surface such as the bottom wall located near the anode with high-pressure washing water to expose a clean metal surface. Further, in the above-described embodiment, the movement of the processing means 17 is controlled by the electromagnet 19
Although it was regulated by the
A propulsion mechanism may be attached to the processing means so that the tank chamber 13 can be moved freely.

In the above-mentioned embodiment, the anode (anode plate 27) and the cathode (cathode plate 28) are rectangular plates, but in the present invention, these are columnar (cylindrical, square columnar, etc.). Alternatively, it may have a mesh shape. Further, in the present invention, only the anode or both the anode and the cathode may be attached directly to the work lid that closes the inspection port.

[0032]

As described above, according to the present invention, it is possible to easily and inexpensively process the residual oil while reducing the load on the environment.

[Brief description of drawings]

FIG. 1 is a partial side sectional view of a tanker showing an embodiment of the present invention.

FIG. 2 is a partially cutaway side view of a processing means.

FIG. 3 is a plan view of processing means.

[Explanation of symbols]

11 ... Oil tanker 13 ... Tank chamber 14 ... Seawater 23 ... Power 27 ... Anode 28 ... Cathode

Claims (3)

[Claims] 1. A step of injecting seawater as ballast water into an empty tank chamber of an oil tanker from which oil has been extracted,
While the oil tanker is navigating, by energizing between the anode and the cathode which are in contact with the seawater in the tank chamber, the seawater is electrolyzed to produce sodium hydroxide, and the tank chamber is generated by the sodium hydroxide. And a step of saponifying the residual oil in the oil tanker. 2. The method for treating residual oil in an oil tanker according to claim 1, wherein the density of the current flowing between the anode and the cathode is in the range of 0.05 to 0.25 mA. 3. An anode and a cathode which are in contact with seawater injected as ballast water into a tank chamber of an oil tanker from which oil has been extracted, and an electric current is applied between the anode and the cathode during the navigation of the oil tanker. And a power source for electrolyzing the seawater to generate sodium hydroxide and saponifying the oil remaining in the tank chamber with the sodium hydroxide.