JP2010177326A - Corrosion-resistant magnetic material, and seawater treatment system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a seawater-resistant magnetic material superior in corrosion resistance and durability against seawater. <P>SOLUTION: The seawater-resistant magnetic material has a coating layer composed of at least one or more kinds of materials selected from nitride-based materials consisting of CrN, TiN, AlN, BN, BCN and AlBN and carbon-based materials including diamond-like carbon (DLC) containing hydrogen or TiC, on a surface coming into contact with seawater, of a substrate made from a magnetic body, and this coating layer is constituted of one or more coating layers. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a corrosion-resistant magnetic material and a seawater treatment apparatus using the material, for example, as a constituent material of a magnetic separation apparatus for treating ballast water composed of seawater mounted in an oil tanker or oilfield associated water containing seawater. It is used.

In recent years, factory wastewater, domestic wastewater, etc. have flowed into seawater through rivers, and there is a tendency for pollution of seawater to expand.
When removing the solids contained in the contaminated water, the amount of water is large, so that the speed of the cleaning process is required. In addition, in water treatment that contains a large amount of microorganisms, plankton, and fungal bodies that cause contamination, it is necessary to capture the above-mentioned removal target with a filtration membrane having micron-scale pores. It takes a long time, and trapped particles are likely to be clogged due to accumulation on the filtration membrane, so that high-speed and large-scale treatment of treated water is difficult due to the necessity of intermittent cleaning.

In recent years, the treatment of ballast water loaded on ships has become a problem. Ballast water is seawater that is loaded for safe navigation even in an empty state. Ballast water is taken from the nearby sea area when leaving the port, and drained to the ocean when loading the cargo when entering the port. That is, ballast water consisting of seawater from the port of departure is drained at the port of arrival. For example, when an oil tanker departing from Japan sails to the Middle East, such as Kuwait, an oil-producing country, It is loaded as ballast water and drained offshore in the waters of the Middle East.
When ballast water is discharged into a sea area different from the sea area where water is taken, organisms in the seawater are moved to sea areas that are not originally habitats, which greatly affects the marine ecosystem.

For this reason, some countries have already regulated the discharge of ballast water. In February 2004, an international convention for “regulation and management of ship ballast water and sediment” was issued by the International Maritime Organization. Adopted, construction ships from 2009 onwards are required to install a ballast water treatment system that conforms to the standards, and to purify 95% or more of the ballast water.
However, in a large tanker with a capacity of 1500 to 5000 tons of ballast water tank, when the ballast water is exchanged to treated water at sea during the voyage from departure to entry, it is necessary to treat in large quantities at a very high speed. is there. Moreover, since micron-unit microorganisms such as algae are contained in seawater, it is difficult to mass-process at high speed as described above.

  Furthermore, the treatment of oil-containing wastewater is often required than before. As this type of oil-containing wastewater, there is, for example, oil field associated water. Oil field-associated water is used to inject oil into the formation's oil layer during crude oil exploration to increase pressure and ensure productivity.Therefore, a large amount of wastewater composed of seawater containing oil is generated. It is called oil field accompanying water. This oilfield-associated water needs to be discarded after the non-aqueous oil is removed.

Conventionally, the present applicant has disclosed in Japanese Patent Application Laid-Open No. 2000-254544 (Patent Document 1) a magnetic separation capable of separating and removing a material to be removed at a relatively high speed from raw water containing the material to be removed made of plant microorganisms such as algae. The device is provided.
The magnetic separation device adds magnetic particles made of iron oxide particles to raw water to impart magnetism to the object to be removed, and then passes the magnetic filter to magnetically adhere the object to be removed to the magnetic filter for separation. It has been removed. Since the object to be removed is separated and removed by magnetism as described above, the object to be removed can be separated and removed even if the water passage hole of the magnetic filter is widened, and the water treatment can be speeded up.

  When the magnetic separation device is used for seawater treatment, the surface of the magnetic material constituting the magnetic separation device in contact with seawater is reduced in magnetism due to salt contained in the seawater, or the surface of the magnetic material is corroded. However, a great deal of labor and labor may occur in replacement and maintenance work, and it is necessary to improve the corrosion resistance against seawater.

Conventionally, as a magnetic material in contact with seawater, for example, in JP-A 2000-176306 (Patent Document 2), in order to recover heavy oil floating in seawater, a magnetic material such as magnetite is dispersed on the sea to obtain oil. On the other hand, it is described that a magnetic force is applied to a buoy of a recovery ship, or a magnetite attached to heavy oil is attached to the buoy or the fence, and the heavy oil is recovered by enclosing it with a magnetic fence.
However, it is only described that the buoy or fence has a built-in magnet and is a magnetic body, and there is no description of the material of the buoy or fence itself that contacts seawater. There is no suggestion of imparting corrosion resistance to.

  Japanese Patent Laid-Open No. 5-302148 (Patent Document 3) discloses a structural material for a bridge exposed to seawater: C: 0.02% or less, Si: 0.5-2%, Mn: 0.05- Contains 0.1%, P: 0.01-0.2%, Cr: 1-5%, Al: 0.5-3%, and N: 0.005-0.5% in iron (Fe) A highly corrosion-resistant ferromagnetic damping alloy has been proposed.

  However, among the metals, Cr effective for corrosion resistance is 1 to 5%, N is a very small amount of 0.005 to 0.5%, and the iron content exceeds 90%. It may appear on the surface and iron corrosion by seawater may occur and proceed easily, and it is necessary to improve the corrosion resistance and durability against seawater.

JP 2000-254544 A JP 2000-176306 A JP-A-5-302148

  This invention is made | formed in view of an above described problem, and makes it a subject to improve the corrosion resistance of a magnetic material which contacts seawater, and durability.

  In order to solve the above-mentioned problems, the present invention provides a diamond-like carbon containing a nitride-based material composed of CrN, TiN, AlN, BN, BCN, and AlBN, and hydrogen on the surface of the substrate made of a magnetic material in contact with seawater. DLC), having a coating layer composed of at least one material selected from carbon-based materials composed of TiC, and the coating layer is composed of one or two or more coating layers Corrosion-resistant magnetic materials are provided.

  As described above, in the present invention, the substrate itself is not alloyed with a seawater-resistant component, but a coating layer having corrosion resistance and durability against seawater on the surface of the substrate made of a magnetic material. Is provided. Thus, it is not necessary to form the substrate with a special alloy, and a substrate with a known degree of magnetic force can be used. And the coating layer is a coating layer made only of the nitride-based metal material or the carbon-based inorganic material having corrosion resistance and durability against seawater, and the substrate such as iron is not in contact with seawater, It can be set as the material which was excellent in corrosion resistance and seawater resistance rather than the alloy of patent document 3. FIG.

In the nitride-based metal material, N is particularly excellent in seawater resistance. Therefore, it is mixed with a metal having excellent seawater resistance composed of Cr, Ti, Al, and B, and iron that is easily rusted and has low corrosion resistance. Since it is not made of an alloy, seawater resistance can be improved.
In the nitride material, the ratio of each alloy is preferably in the following range.
In particular, when the substrate is a metal, from the viewpoint of the thermal expansion coefficient, the coating layer preferably has an inclined structure in which the metal on the substrate side is rich in the nitride material and nitrogen is increased toward the surface side.
The nitride material can be changed in the following range.
CrN is Cr: N = 99: 1 to 20:80
TiN is Ti: N = 99: 1 to 20:80
AlN is Al: N = 99: 1 to 20:80
BN is B: N = 95: 1 to 20:80
AlBN is Al: B: N = 98: 1: 1 to 20:20:60
BCN is B: C: N = 80: 15: 5-20: 20: 60

  In the carbon system, diamond-like carbon (DLC) containing hydrogen is particularly preferable, and the present inventors have found through experiments that TiC (Ti: C = 90: 10 to 30:70) is excellent in seawater resistance. is doing.

  In particular, a base layer composed of one type of coating layer selected from the nitride-based material on the surface of the substrate, and a coating layer composed of diamond-like carbon further containing hydrogen on the surface of the metal coating layer of the base layer. It is preferable that they are laminated.

The magnetic substrate is made of stainless steel, iron, nickel, cobalt, samarium, neodymium, tungsten, chromium, aluminum, barium, strontium, boron, platinum, niobium, manganese, praseodymium, magnetic polymer having a magnetic susceptibility of 10 cgs or more. It consists of an aggregate of at least one or two or more selected alloys or oxides.
Any substrate can be used from the required mechanical properties such as strength and tensile force, but the substrate has a magnetic susceptibility of at least 10 cgs.
This is because the magnetic force becomes weak at a magnetic susceptibility of less than 10 cgs when coated with the surface coating layer.

The coating layer is preferably formed integrally with the substrate by vapor deposition, arc vapor deposition, sputtering or plasma spraying on the substrate, and the thickness of the coating layer is preferably 0.01 μm or more and 100 μm or less.
The thickness of the coating layer is the thickness of one layer when the coating layer is one layer, and the total thickness when the coating layer is a plurality of layers.

The thickness of the coating layer is set to 0.01 μm or more. When the thickness is less than 0.01 μm, wear easily occurs due to contact with other members. This is due to the occurrence of a loss of durability.
On the other hand, when the thickness of the coating layer exceeds 100 μm, the magnetic characteristics such as magnetic susceptibility and saturation magnetic characteristics of the magnetic filter deteriorate. Further, the weight increases, the cost increases, and the magnetic force generated depending on the type of the base material is weakened.
The thickness of the coating layer is more preferably 0.1 μm to 5 μm.

The coating layer only needs to be provided on the surface in contact with seawater. When seawater is circulated in the pipe, the inner peripheral surface of the pipe is covered with a dry process such as vapor deposition, arc vapor deposition, sputtering or plasma spraying. Forming a layer. This is because it is difficult to use a wet process such as plating because the melting point of the ceramic forming the coating layer is high.
When the entire surface is in contact with seawater, the coating layer is provided on the entire surface of the substrate.
As described above, when a coating layer is formed by arc vapor deposition, sputtering or plasma spraying, the coating layer can be firmly integrated with the substrate, and cracks and the like are generated between the substrate and the coating layer even when used over time. It can prevent peeling. In particular, it is necessary to pay attention to voids in the film due to minute fine powders, and the method of installing the substrate during vapor deposition is also important. For example, it is preferable to face down or sideways without placing the substrate upward as much as possible.

  The present invention also provides a magnetic filter for a magnetic separation device used for seawater treatment, a pipe for housing the magnetic filter, a pipe connected to the magnetic separation apparatus, and a pump interposed in the pipe. There is provided a seawater treatment apparatus characterized in that it is at least one component and the covering layer is disposed on a surface in contact with seawater.

The magnetic separation device can be suitably used for purifying seawater including ballast water and oilfield-associated water, or for desalination.
As mentioned above, in recent years, treaties have been required to treat ballast water loaded on ships, and it is necessary to treat a large amount of ballast water at a high speed from the second port to the arrival port. A magnetic separation device is preferably used because water can be treated.
In the apparatus for purifying oil field-associated water and the seawater desalination apparatus, a large amount of seawater needs to be processed at high speed, and a magnetic separation apparatus is preferably used.
As described above, in the case where the magnetic separator is provided with a component made of a magnetic material on the surface in contact with seawater, the above-described corrosion-resistant magnetic material can be used to improve the corrosion resistance and durability, and the magnetic separator itself The service life of can be prolonged.

The corrosion-resistant magnetic material of the present invention is not limited to the constituent material of the magnetic separation device, and when the substrate is a magnetic body such as stainless steel or iron, the surface of the magnetic body is covered with the coating layer to prevent corrosion. Since it has excellent durability, it can be suitably used as a constituent material in contact with seawater. In particular, it can be suitably used as a constituent material that forms a tank or a pipe of a filtration device such as a pump, or when the seawater is purified by a filtration device of a hollow fiber membrane, such as a pump. .
Further, when heavy oil flows out to the ocean described in Patent Document 2, even when the magnetic particles are dispersed on the heavy oil floating in the ocean and the heavy oil is recovered by the magnetic separation device, the recovery member and the magnetic separation device The corrosion-resistant magnetic material of the present invention can be used as a constituent material.

  As described above, the corrosion-resistant magnetic material of the present invention is a material having excellent seawater resistance because a coating layer having excellent corrosion resistance and durability against seawater is provided on the surface of a substrate made of a magnetic material that contacts seawater. It can be. In particular, it is not necessary to form the substrate itself with a special alloy having seawater resistance, and it is only necessary to provide the coating layer only on the surface in contact with seawater. Therefore, the seawater-resistant material is easily excellent in corrosion resistance and durability. It can be.

It is sectional drawing of 1st embodiment of the magnetic material for seawater resistance of this invention. It is sectional drawing of 2nd embodiment. It is sectional drawing of 3rd embodiment. It is a general view which shows roughly the case where a magnetic separation apparatus is used for the ballast water treatment of 4th embodiment. It is sectional drawing of a magnetic separation apparatus. (A) is a side view which shows the magnetic filter used for a magnetic separation apparatus, (B) is a principal part expanded sectional view. It is a block diagram of a ballast water treatment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1, 2 and 3 show first to third embodiments of the corrosion-resistant magnetic material of the present invention.
The corrosion-resistant magnetic material 1A of the first embodiment shown in FIG. 1 is provided with a coating layer 3 made of one nitride material selected from CrN, TiN, AlN, BN, BCN, and AlBN on the surface of a substrate 2. ing. In the present embodiment, the coating layer 3 is made of CrN (chromium nitride), and the substrate 2 is a magnetic body made of stainless steel having a magnetic susceptibility of 10 cgs or more.
The CrN preferably has a Cr: N ratio of 90:10 to 40:60, and the CrN of this embodiment has a Cr: N ratio of 60:40.

The coating layer 3 made of CrN is formed integrally with the substrate 2 by vapor deposition, arc vapor deposition, sputtering or plasma spraying on the substrate 2, and in this embodiment, arc vapor deposition is adopted.
Arc deposition is performed by depositing a coating layer 3 by depositing molten CrN at a thickness of 0.01 μm to 100 μm on the entire surface of one surface of the substrate 2 made of stainless steel under the condition that the ambient temperature is 30 ° C. to 200 ° C. , Integrated. In the present embodiment, the thickness of the substrate 2 is 800 μm, and the thickness of the coating layer 3 is 3.5 μm.

A corrosion-resistant magnetic material 1B of the second embodiment shown in FIG. 2 includes a carbon-based coating layer 3 made of diamond-like carbon (DLC) containing hydrogen or TiC on the surface of a substrate 2. Since DLC is particularly excellent in seawater resistance among the carbon series, the coating layer 3 of the present embodiment is formed of DLC.
In the present embodiment, the substrate 2 is a magnetic body made of iron having a magnetic susceptibility of 10 cgs or more and a thickness of 1500 μm, which is thicker than that of the first embodiment.
The coating layer 3 made of DLC is formed integrally with the substrate 2 by vapor deposition, arc vapor deposition, sputtering, or plasma spraying on the substrate 2 as in the first embodiment. In this embodiment, sputtering is employed. The thickness of the coating layer 3 is 8 μm, which is thicker than that of the first embodiment.

  The corrosion-resistant magnetic material 1C of the third embodiment shown in FIG. 3 is provided with the same coating layer 3-1 made of CrN as that of the first embodiment on the surface of the substrate 2 made of the same stainless steel as that of the first embodiment. A coating layer 3-2 on the surface side made of the same DLC as in the second embodiment is provided on the surface of the coating layer 3-1, and a structure having two coating layers 3-1, 3-2 is provided.

The coating layer 3-1 is formed on the substrate 2 by arc vapor deposition, and then the coating layer 3-2 is formed by sputtering DLC on the surface of the coating layer 3-1.
The thickness of the substrate 2 made of stainless steel is 2700 μm, the thickness of the coating layer 3-1 made of CrN is 5 μm, the thickness of the coating layer 3-2 made of DLC is 5 μm, and the coating layers 3-1 and 3-2 The total thickness is 10 μm, and the total thickness of the corrosion-resistant magnetic material is 2710 μm.

  An evaluation test of the corrosion-resistant magnetic material of the first to third embodiments was performed.

  As a result of experimenting by immersing each seawater-resistant magnetic material of the first to third embodiments in seawater for 100 days, as compared with the case where each consists only of a substrate not covered with the coating layer 3, It was confirmed that corrosion did not occur and the corrosion resistance was excellent. Among these, in particular, when the underlying coating layer 3-1 of the third embodiment is CrN and the surface-side coating layer 3-2 is DLC, the corrosion resistance is excellent.

A fourth embodiment is shown in FIGS.
The fourth embodiment comprises a magnetic separation device used for ballast water treatment, and the corrosion-resistant magnetic material is used as a constituent material of the magnetic separation device.

As shown in FIG. 4, ballast water Q <b> 1 made of seawater is supplied from a ballast water tank 101 mounted on the ship 100 through a pipe 11 provided with a pump 12 to a magnetic separation device 10 mounted on the ship 100. . In addition, the magnetic particles P are introduced into the ballast water Q1 in the magnetic particle supply tank 13 before being distributed to the magnetic separation device 10, and adhere to non-magnetic substances composed of plant microorganisms or animal microorganisms including algae floating and precipitated in the ballast water. To give magnetism.
The ballast water tank 101, the piping 11, the housing of the pump 12, and a constituent material including a rotating member (not shown) and the magnetic particle supply tank 13 are made of a material having strength such as stainless steel or iron. Since these stainless steel and iron are magnetic materials, corrosion easily occurs on the surface in contact with seawater. Therefore, the tank 101, the pipe 11, and the pump are made of the corrosion-resistant magnetic material according to any one of the first to third embodiments. 12 and magnetic particle supply tank 13 are formed to enhance corrosion resistance and durability.

  As shown in FIG. 5, the magnetic separation device 10 has a configuration in which a magnetic filter 18 is provided in parallel with a pipe 16 surrounded by a magnet 15. It forms with the magnetic material for seawater resistant which consists of either of embodiment. In FIG. 5, reference numeral 19 denotes a cleaning mechanism for the magnetic filter 18.

Specifically, the pipe 16 is formed of a seawater-resistant magnetic material in which an inner peripheral surface that contacts the seawater of a substrate made of stainless steel is covered with the nitride-based and / or carbon-based coating layer.
Further, the magnetic filter 18 shown in FIGS. 6 (A) and 6 (B) has a structure in which the entire surface of the porous substrate 18a provided with a large number of holes made of a magnetic material mainly composed of stainless steel, iron, nickel, cobalt, etc. It is formed of a seawater-resistant magnetic material coated with a ride-based and / or carbon-based coating layer 18b. The magnetic filter 18 may be a wire mesh made of a wire made of a magnetic material having the coating layer.

As shown in FIG. 7, the magnetic separation device 10 in which the magnetic filter 18 is accommodated in the piping 16 is provided in a plurality of stages, and the piping 21 and the pump 22 for connecting the magnetic separation device 10 are also formed of a magnetic material for seawater resistance. is doing.
Further, a filtration device 27 in which a hollow fiber membrane module 25 is accommodated in a tank 26 is provided downstream of the magnetic separation device 10, and the treatment liquid filtered by the filtration device 27 is supplied to the ballast water tank 101 through a pipe 28. It is returning.
Since the pipe 21, the pump 22, the tank 26 of the filtration device 27, and the inner surface of the pipe 28 are also in contact with seawater, they are formed of the corrosion-resistant magnetic material coated with the nitride-based and / or carbon-based coating layer.

As described above, if a magnetic separation device is configured using a corrosion-resistant magnetic material having a seawater-resistant coating layer on the surface that contacts seawater, the durability of the magnetic separation device itself can be improved. The service life of the device can be extended.
Further, the solid material can be separated and removed from a large amount of ballast water at high speed by the magnetic separation device, and the fine solid material that could not be removed by the magnetic separation device can be reliably removed.

  The magnetic separation device is used not only for ballast water treatment, but also for oil field accompanying water, pretreatment device for seawater desalination equipment desalination process, and seawater purification equipment. In the case of using a body, the use of a magnetic material obtained by coating these magnetic bodies with the above-mentioned nitride-based and / or carbon-based coating layers can improve corrosion resistance and durability.

1 (1A, 1B, 1C) Corrosion-resistant magnetic material 2 Substrate 3 (3-1, 3-2) coating layer 10 Magnetic separator

Claims (6)

  The surface of the substrate made of magnetic material that comes into contact with seawater is selected from a nitride material made of CrN, TiN, AlN, BN, BCN, AlBN, diamond-like carbon (DLC) containing hydrogen, and a carbon material made of TiC. A corrosion-resistant magnetic material comprising: a coating layer composed of at least one kind of material, wherein the coating layer is composed of one or two or more coating layers.   A base layer made of one type of coating layer selected from the nitride-based material is laminated on the surface of the substrate, and a coating layer made of diamond-like carbon containing hydrogen is further laminated on the surface of the coating layer of the base layer. The corrosion-resistant magnetic material according to claim 1.   The magnetic substrate is made of stainless steel, iron, nickel, cobalt, samarium, neodymium, tungsten, chromium, aluminum, barium, strontium, boron, platinum, niobium, manganese, praseodymium, magnetic polymer having a magnetic susceptibility of 10 cgs or more. The corrosion-resistant magnetic material according to claim 1 or 2, which is an aggregate of at least one or two or more selected alloys or oxides.   The coating layer is formed integrally with the substrate by vapor deposition, arc vapor deposition, sputtering or plasma spraying on the substrate, and the thickness of the coating layer is 0.01 μm or more and 100 μm or less. The corrosion-resistant magnetic material according to any one of the above.   A magnetic filter of a magnetic separator used for treating seawater with the corrosion-resistant magnetic material according to any one of claims 1 to 4, a pipe accommodating the magnetic filter, a pipe connected to the magnetic separator, A seawater treatment apparatus, characterized in that it is at least one constituent material of a pump interposed in a pipe, and the covering layer is disposed on a surface in contact with seawater.   The seawater treatment device according to claim 5, wherein the magnetic separation device is used for purifying seawater including ballast water and oilfield associated water, or for seawater desalination.

Images