KR20120128083A - Oil Purification Method and Apparatus with Porous Membrane - Google Patents

Abstract

PURPOSE: Oil purification method and apparatus using a porous film capable of increasing the lifetime of lubricating oil are provided to filter nanosized components from the lubricating oil. CONSTITUTION: An oil purification apparatus using a porous film comprises the following: the porous layer(1) formed by melting and sintering nanosized metal or metal oxide; and more than one carbon nano structure(2) connected to each other by the melting of the metal or metal oxide. The porous layer includes pores(3). The carbon nano structures are heated to be connected to each other.

Description

Oil Purification Method and Apparatus Using Porous Membrane {Oil Purification Method and Apparatus with Porous Membrane}

The present invention relates to a method and apparatus for purifying oil or waste oil in use using a composite of carbon nanostructure-metal or silicon oxide.

Recently, as the industry is advanced, membrane technology having high purity resolution is recognized as a very important field. Increasingly important in the chemical, food, pharmaceutical, medical, biochemical and environmental sectors.

In the field of oil, environmental and economic aspects of long-term use of oils by using oils such as oils such as lubricating oils during or after use are filtered.

The lubricating oil, which is an exemplary oil of the oil of the present invention, prevents the surface from being worn or damaged by high pressure and friction at the uneven surface of the friction part, and serves to improve the efficiency of the machine by reducing power consumption. do. Another function of lubricating oil is to absorb the heat generated from the friction surface and to send it to the outside to prevent it from sticking, to disperse the load concentrated on the contact surface, and to seal the two friction surfaces to prevent intrusion of water or dust. It serves to prevent corrosion of the lubricating surface by oxygen and water.

These lubricants contaminate the lubricant with worn metal chips and burned carbides during operation of the device, which degrades the performance of the lubricant. On the other hand, it is necessary to install a component for filtering and lubricating oil in the apparatus or to replace it with a new lubricant after a certain time of use has elapsed. In addition, the used waste lubricating oil is recycled or reused as fuel oil through a regeneration process.

As a method of removing impurities from the lubricating oil, a centrifugal separator may be used (Korean Patent Application No. 10-2006-7002799, European Patent Publication No. EP 20040741406), or fine iron particles may be removed using a magnetic force (Korean Patent Application No. 10). -1999-0049190), the method of filtration using an oil filter (Korean Patent No. 10-1996-040148, Korean Patent No. 10-2003-0065486, Korean Patent No. 1990-0014047, Korean Patent No. 10-2000-7014517, European Patent Publication No. EP 2008066756, are disclosed in. And after the use of the method for purifying the waste lubricating oil to remove the compound by adding a compound (Korean Patent Application No. 10-1999-0036078), a method using a catalyst (Korean Application No. 10-2004-0005708), screw A method of use (Korean Utility Model Nos. 20-2005-0003461 and 20-2005-0003462) is disclosed.

However, such a purification method has a problem that the microparticles can be removed by separation and filtration, but nanoparticles are not separated. In particular, nano particles of a certain size or more degrade the performance of the lubricant, causing a major obstacle in reuse. These nanoparticles have a problem of reducing the performance and life of the oil filter as well as the lubricant. In addition, due to the high viscosity of the lubricating oil, it is necessary to filter the lubricating oil at a high temperature in order to filter and refine the lubricating oil. However, the conventional oil refining method has a problem of deformation at high temperature because it uses an oil filter made of a polymer as the base material.

The present invention is to solve the above problems by using a composite nanoporous membrane of carbon nanostructure-metal or metal oxide that can remove the fine nanoparticles from the oil or waste oil used in the machine using the oil even at high temperature It is to provide a method and a refining apparatus for refining oil.

The present invention relates to an oil refining method comprising the step of purifying impurities from oil using a porous membrane in which a plurality of carbon nanostructure-metal or metal oxide complexes are bonded to each other to form pores.

The present invention also has a plurality of carbon nanostructures-metal or metal oxide complexes formed by the mutually bonded pores, the basis weight of the carbon nanostructures-metal or metal oxide complex is 0.05 mg / cm ² to 10 mg / cm ² It relates to a porous membrane for phosphorus oil purification.

The present invention also provides an oil introduction tube into which oil is introduced;

An oil refining unit including a porous membrane containing a complex of carbon nanostructure-metal or metal oxide for refining the oil introduced from the oil inlet tube;

An oil discharge pipe for discharging the purified oil from the oil refining unit; And

An oil refining apparatus including an oil heating unit for heating oil.

The invention also relates to a machine having an oil outlet and an oil inlet;

An oil introduction pipe fluidly connected to the oil outlet and introducing oil flowing out of the machine into an oil refining unit;

An oil refining unit including a porous membrane containing a complex of carbon nanostructure-metal or metal oxide for refining the oil introduced from the oil inlet tube; And

It relates to an oil refining system including an oil discharge pipe in fluid communication with the oil inlet for introducing the oil purified in the oil refining unit into the machine.

The oil refining method and apparatus according to the present invention has an advantage of removing nano fine materials from oil including waste oil using a nanoporous membrane of a composite of carbon nanostructure-metal or metal oxide.

In the oil refining method and apparatus according to the present invention, the nanoporous membrane has excellent thermal stability, and for example, various oils that can be used in automobiles, ships, insulation, gears or turbines can be purified during the use of mechanical devices. In addition, the waste oil after a certain time of use has the advantage that can be regenerated at a high temperature.

In addition, the oil refining method and apparatus according to the present invention is effective to increase the service life of the lubricating oil by filtering the nano-fine material in the lubricating oil can be used as an environmentally friendly oil refining method and apparatus.

1 is a conceptual diagram showing the structure of a porous membrane according to an embodiment of the present invention.
Figure 2 is a schematic diagram showing a waste oil purification apparatus according to an embodiment of the present invention.
3 is a schematic diagram illustrating an oil refining system according to another embodiment of the present invention.
4 is a schematic diagram illustrating an oil refining system according to another embodiment of the present invention.
5 is a scanning electron microscope (SEM) photograph of the carbon nanotube-silver composite prepared in Preparation Example 1. FIG.
6 is a scanning electron microscope (SEM) photograph of the carbon nanotube-nickel composite prepared in Preparation Example 2. FIG.
7 is a scanning electron microscope (SEM) photograph of the oil filter prepared in Preparation Example 3. FIG.
8 is a view showing the particle size analysis results of the waste lubricating oil before purification.
9 is a view showing the particle size analysis results of the waste lubricating oil purified by the oil filter according to Example 1 of the present invention.

In order to achieve the above object, the present inventors have conducted research, and as a result, the nanoporous membrane of the composite of carbon nanostructure-metal or metal oxide according to Korean Patent Application No. 10-2009-0026356, which is hereby incorporated by reference in its entirety. It was found that nano microparticles could be removed from this oil.

Hereinafter, the porous membrane for oil refining, the oil refining method and apparatus of the present invention will be described in detail. Hereinafter, the technical and scientific terms used herein will be understood by those skilled in the art without departing from the scope of the present invention. Descriptions of known functions and configurations that may be unnecessarily blurred are omitted.

As used herein, the term “composite of carbon nanostructure-metal or metal oxide” refers to a composite in which two or more metals or metal oxides are uniformly dispersed on the surface of the carbon nanostructure.

As used herein, the term “uniform dispersion” does not necessarily mean mathematically uniform. That is, it does not necessarily mean that a plurality of metals or metal oxides are formed on the surface of the carbon nanostructure at the same interval, and include a case where they are randomly dispersed.

As used herein, the term “porous membrane” refers to a membrane or a filter in which a plurality of complexes of the carbon nanostructure-metal or metal oxide are bonded to each other to form a plurality of pores. The porous membrane may include additional elements, for example magnetite, etc. as needed in addition to the composite of carbon nanostructure-metal or metal oxide, and may be modified with additional organic functional groups such as hydrophilic or hydrophobic functional groups. . Nanoporous membrane refers to the porous membrane having a pore size of several to several hundred nm.

As used herein, the term "refining" refers to any process of increasing the purity of raw materials by removing foreign substances or contaminants from raw materials. Purification includes, for example, filtration that physically blocks certain materials and allows other materials to pass through. Purification also includes adsorption, for example, by physically or chemically adsorbing and separating a particular substance.

As used herein, the term “oil” refers to a substance that is liquid at room temperature and is not mixed with water but can be mixed with other oils or organic solvents. Oils include, for example, vegetable oils, essential oils, petrochemical oils, and synthetic oils. For example, the oil includes lubricating oil which is used for the purpose of reducing frictional force generated on the friction surface of the machine or dispersing frictional heat generated in the friction surface.

As used herein, the term “impurity” refers to components other than oil that are included in the oil and require purification. In particular, the impurities include fine particles having a size of 20 nm or more, for example iron particles, carbon precipitates.

  It refers to a membrane or a filter in which the carbon nanostructure-composite of metal or metal oxide are bonded to each other to form a plurality of pores.

The present invention relates to an oil refining method comprising the step of purifying impurities from oil using a porous membrane in which a plurality of carbon nanostructure-metal or metal oxide complexes are bonded to each other to form pores.

Referring to FIG. 1, the metal or metal oxide 1 in the porous membrane is obtained by melting or sintering a nano-sized metal or metal oxide 1. Therefore, the porous membrane of the network structure in which one or more carbon nanostructures 2 are connected to each other by the molten or sintered metal or metal oxide 1 has pores 3. That is, when the carbon nanostructures 2 are uniformly dispersed on the surface and have a plurality of metals or metal oxides 1 having a predetermined size, a plurality of metals formed on one carbon nanostructure 2 are heated. Or some or all of the metal oxide (1) is melted to connect the other carbon nanostructures (2). The porous membrane may be in the form of a single membrane or a composite membrane supported on a support. In the case of the composite membrane form, for example, HEPA filter, ULPA filter, glass fiber filter, glass powder sintered filter, polymer nonwoven fabric filter, Teflon membrane filter, metal powder sintered filter, as disclosed in Korean Patent Application No. 10-2009-0026356, Or on a support such as a metal wire woven filter, ceramic filter, or the like. A single film is selected, for example, when a support of a material is burned at a temperature below the melting temperature of the metal or metal oxide or decomposed by an alkaline solution, and the support is burned at a melting temperature of the metal or metal oxide or decomposed in an alkaline solution. You can get it.

Nanoporous membrane according to the present invention has pores between the carbon nanostructures, the pore size may be, for example, 10 nm to 500 nm, 50 nm to 300 nm, for example, 30 nm to 80 nm. If there are pores within the above numerical range, impurities to be purified can be purified with high efficiency. If the pore size is smaller than the above range, the fluidity is poor, and if the pore size is too large, nanoparticles cannot be filtered. The pore size of the nanoporous membrane may be controlled by the nanoporous membrane thickness depending on the size of the carbon nanostructure or the amount of the composite of the carbon nanostructure-metal or metal oxide. Specifically, the size of the carbon nanostructure, for example, the diameter of the carbon nanostructure according to the type of the carbon nanostructure can be controlled by the type of carbon nanostructure, the size of the pores, and also the carbon nanostructure of the metal or metal oxide The pore size may be controlled by the thickness of the nanoporous membrane according to the amount of the composite. It can be changed according to the type of metal and carbon nanostructures used, but as an example, the porous membrane according to the present invention has pores formed by combining a plurality of carbon nanostructures-metal or metal oxide composites, The basis weight of the composite of carbon nanostructure-metal or metal oxide is 0.05 mg / cm ² to 10 mg / cm ² , for example 0.1 mg / cm ² to 10 mg / cm ² , for example 0.5 mg / cm ² to 3 mg / cm ² , for example, from 0.7 mg / cm ² to 1.5 mg / cm ² . When the amount of the composite is too small, the formation of the porous membrane may not be easy or the size of the pores may be too large. On the contrary, when the amount of the composite is too large, the size of the pores may be too small or the flowability of the oil may be poor.

The carbon nanostructures include single wall carbon nanotubes, double wall carbon nanotubes, multi wall carbon nanotubes, carbon nano horns, and carbon. Carbon nano fiber, graphene or a mixture thereof.

For example, in order for the nanoporous membrane to have a pore size of 10 nm to 500 nm, the carbon nanostructures may include single wall carbon nanotubes, double wall carbon nanotubes, and multiplexes. It may be selected from multi wall carbon nanotubes or mixtures thereof.

In the metal or metal oxide, the metal is Mg, Al, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Rb, Sr, Y, Zr, Mo, Ru , Rh, Pd, Ag, Cd, In, Sn, Cs, Ba, La, Ce, Nd, Sm, Eu, Gd, Tb, Hf, Ir, Pt, Tl, Pb and Bi or It may comprise two or more metals. The metal may comprise, for example, Ag, Ni, Cu, Co, Sn or mixtures thereof.

Although it may be changed depending on the type of metal and carbon nano structure used, the composite of carbon nano structure-metal or metal oxide contains 5 to 70% by weight of metal or metal oxide, and 30 to 95% by weight of carbon nano It can contain a structure. When the content of the metal or metal oxide is less than 5% by weight, it is difficult to connect the carbon nanostructure into a network by melting or sintering the metal or metal oxide, and the membrane support and the composite of the carbon nanostructure-metal or metal oxide There is a risk that a stable bond is not made, and if it exceeds 70% by weight, there is a problem that the flow of oil is not smooth because the metal blocks pores of the nanoporous membrane.

In the carbon nanostructure-metal or metal oxide composite, the carbon nanostructure and the metal may each have a size of several nm to several hundred nm, and more specifically, the nano metal particles and the carbon nanostructure of 1 nm to 500 nm. It can have

The complex of carbon nanostructure-metal or metal oxide may be prepared by mixing and heat treating a dispersion of a carbon nanostructure and a metal precursor dispersed in a reducing solvent. The reducing solvent may be selected from, for example, polyhydric alcohols, glycol ethers, or mixtures thereof. The dispersion may further comprise a stabilizer. The complex may be prepared by, for example, the method described in Korean Patent Application No. 10-2009-0026356, but is not limited thereto.

The carbon structure-metal or metal oxide composite thus prepared has a structure in which spherical metal particles of 1 nm to 500 nm formed by reduction of a metal or metal oxide precursor are bonded or mixed to the carbon nanostructure.

The nanoporous membrane is prepared using the above-described composite of carbon nanostructure-metal or metal oxide. For example, the nanoporous membrane is prepared by coating the carbon nanostructure-composite of a metal or metal oxide on a support and then heat-treating the metal or metal oxide to connect the carbon nanostructure to a network structure.

In the nanoporous membrane production, the heat treatment may be performed at a low temperature of 100 to 700 ° C., for example, 100 to 500 ° C. for 3 to 10 hours to melt or sinter the metal to form a network structure. The heat treatment may be, for example, a heat treatment in a general low temperature oven, a method of passing a heat roller, a heat treatment in a high temperature electric furnace, a heat treatment using an infrared lamp, and the like. When the metal is silver, for example, nanoporous membranes may be manufactured by extremely low temperature heat treatment at 100 to 300 ° C.

Since the size of the metal of the carbon nanostructure-metal or metal oxide composite is nano units, the melting point of the metal is lower than that of the metal of the normal size. For this reason, even when heat-treated at a relatively low temperature, the carbon nanostructure-metal composite of the network structure is connected to each other by melting or sintering the metal to prepare a composite nanoporous membrane of carbon nanostructure-metal. The porous membrane may be prepared by, for example, the method described in Korean Patent Application No. 10-2009-0026356, but is not limited thereto.

In the oil refining method of the present invention, the oil temperature of the refining step may be, for example, 50 ° C. or higher and less than the thermal denaturation temperature of the oil. The thermal denaturation temperature of the oil is known in the art depending on the type of oil, for example the oil may generally be thermally denatured at 200 ° C, 300 ° C or 400 ° C or higher. In general, the viscosity of the oil is higher than water, and this has the disadvantage that the flow rate is not sufficient when filtering. In the case of automotive lubricating oil, the viscosity is 300 cP to 1,500 cP at room temperature, and the viscosity is low to 60,000 cP at -40 ° C. At this low viscosity, the flow rate is inevitably low to filter the oil, and especially in the case of nanoporous nanoporous membranes, the flow rate is too low to be purified. Therefore, in order to smoothly purify the lubricating oil, it is necessary to lower the high viscosity of the lubricating oil by heating the lubricating oil. However, the conventional oil refining method has a problem of deformation at high temperature because the oil filter is made of a polymer as the base material. However, the nanoporous membrane used in the present invention is composed of carbon and metal components, and there is no problem even if the purification at a high temperature. Oil refining method according to the invention can be purified at a relatively high temperature compared to the existing filter. If the refining temperature is lower than 50 ℃ flow rate is too low has a disadvantage of low purification efficiency, if higher than the thermal modification temperature of the oil to be purified has the disadvantage that the oil is deteriorated.

In the oil refining method of the present invention, the oil viscosity of the refining step may be, for example, 1 cP to 300 cP. Since the viscosity of the lubricating oil at 150 ° C. is generally known as 2 to 10 cP, the oil refining temperature can be controlled, for example, from 70 ° C. to 200 ° C., for example from 100 ° C. to 150 ° C. In order to lower the viscosity of the oil to 1 cP or less at the refining temperature, the temperature must be very high. In this case, the oil is deteriorated, and the flow rate is too low at 300 cP or higher. The oil filter using the nanoporous membrane is purified during or after the use of oil. In the case of lubricating oil, it is effective to purify at a high temperature due to the high viscosity. The nanoporous membrane is composed of carbon and metal, and thus, 50 ° C. to Purification is possible at a high temperature of 300 ℃.

The oil refining method of the present invention can be used to purify oils for automobiles, ships, insulation, gears, turbines, freezers, bearings, automatic transmissions, compressors, cutting or heat medium. It can be used as a method of refining oil during use, mounted on an insulation device, gear device, turbine device, refrigerator, automatic transmission or compressor, etc., and can be used as a method of regenerating waste oil used for the same purpose.

In addition, the oil is not particularly limited and includes lubricating oil. The lubricating oil may be a precision machine oil such as a watch or a measuring instrument; Spindle oil, such as for spindles used in high speed rotating parts of spinning machines; Dynamo milk, such as for motors and generators; Machine oils, such as for bearings of general machinery; Turbine oils, such as for steam turbines; Compressor oils, such as for cylinders in gas compressors; Motor oils, also referred to as mobile oils, for automotive engine lubrication; Aviation lubricants, such as for aircraft piston engines; Diesel engine oils such as low speed and high speed diesel engines having a high flash point for gas engines; Marine engine oils such as high viscosity lubricating oils that withstand the high loads of marine engines, where seawater may enter the oil; Axle oils such as high viscosity lubricating oil having excellent oil resistance to withstand impacts under heavy loads such as tanks; Or cylinder oil having the highest viscosity for internal use of the steam engine. Lubricants also include steel immersion oil, metal cutting oil, metal rust preventive oil and transformer base oil.

In the present invention, the impurities separated from the oil are not particularly limited, but for example, fine particles having a size of at least 20 nm, at least 50 nm, at least 80 nm, at least 300 nm, or at least 500 nm, for example, iron powder. Particles, or carbon precipitates. The microparticles can have a size of, for example, 30 nm to 80 nm, 50 nm to 300 nm, or 100 nm to 500 nm.

The present invention also relates to an oil refining apparatus and system comprising the porous membrane and recirculating and refining the used waste oil or circulating and refining the oil used in a high temperature environment.

Oil refining device according to an embodiment of the present invention is a device for refining and recycling the waste oil used. 2, the apparatus includes an oil introduction pipe 21 into which oil is introduced; An oil refining unit 20 including a porous membrane containing a complex of carbon nanostructure-metal or metal oxide for refining the oil introduced from the oil inlet tube; An oil discharge pipe 22 for discharging the refined oil from the oil refining unit; And an oil heating unit 30 for heating the oil. 2 is a structure in which the oil heating part 30 is formed in the oil inlet pipe 21. If necessary, the oil heating unit 30 may be formed in the oil purification unit 20. For example, the oil inlet pipe 21 and the oil refining unit 20 may have a structure in which the oil heating unit 30 is formed.

The porous membrane may have a network structure in which metals or metal oxides connect carbon nanostructures, and the pore size of the porous membrane may be, for example, 10 nm to 500 nm. A detailed description of the porous membrane is as described above. The structure of the oil refining unit including the porous membrane may be arbitrarily selected by those skilled in the art. For example, the porous membrane may be mounted to the oil refining unit in the form of a flat membrane or a hollow fiber membrane.

Oil heating unit 30 is to increase the temperature of the waste oil to increase the efficiency of the refining. The oil temperature to be purified is, for example, 50 ° C. or higher and may be below the thermal denaturation temperature of the oil. The description of the specific oil temperature and thus the appropriate viscosity is as described above. The oil heating unit 30 is not particularly limited as long as it can control the temperature of the oil in the refining step, but may be formed in any one or more of the oil introduction pipe 21 and the oil refining unit 20. . In addition, the oil heating unit may include an oil heating means, a temperature measuring and control means, and the like, and each configuration may be appropriately selected by those skilled in the art as needed.

In addition, the oil refining apparatus may further include an oil cooling unit (not shown) for cooling the temperature of the discharged oil. The discharged oil may be cooled at room temperature. However, if there is a subsequent process, such as packing the oil to be purified and regenerated in a container, it may further include an oil cooling unit for cooling the heated oil in consideration of the efficiency and stability of the process. In addition, the oil cooling unit may include an oil cooling unit, a temperature measuring and control unit, and the like, and each configuration may be appropriately selected by those skilled in the art as needed.

Oil refining system according to another embodiment of the present invention is to circulate and refine the oil used in a high temperature environment. 3 and 4, the system includes a machine 10 having an oil outlet and an oil inlet; An oil inlet pipe 21 fluidly connected to the oil outlet and introducing oil flowing out of the machine into an oil refining unit; An oil refining unit 20 including a porous membrane containing a complex of carbon nanostructure-metal or metal oxide for refining the oil introduced from the oil inlet tube; And an oil discharge pipe 22 fluidly connected to the oil inlet to introduce the oil refined in the oil refining unit into the machine. If necessary, the oil refining unit 20 may have a structure in which a separate oil heating unit (not shown) is formed.

The porous membrane may have a network structure in which metals or metal oxides connect carbon nanostructures, and the pore size of the porous membrane may be, for example, 10 nm to 500 nm. A detailed description of the porous membrane is as described above. The structure of the oil refining unit including the porous membrane may be arbitrarily selected by those skilled in the art. For example, the porous membrane may be mounted to the oil refining unit in the form of a flat membrane or a hollow fiber membrane.

Unlike the oil refining apparatus for regenerating waste oil described above, in the present embodiment, when the oil itself acting in a machine requiring oil has a certain high temperature, a separate oil heating part is not necessarily required. However, when the temperature of the oil discharged from the machine is different from the appropriate refining temperature, it may further include a first temperature control unit 11 is formed in the oil inlet pipe or oil refining unit to control the temperature of the oil flowing out of the machine have. The first temperature control unit 11 serves to change the temperature of the oil flowing out of the machine to a purification temperature suitable for purification, and may include cooling or heating means and temperature measuring and control means. In addition, the oil refining system is formed in the oil discharge pipe, when there is a difference between the oil discharged from the oil refining unit and the operating temperature operating in the machine, the second temperature control unit 12 for controlling the temperature of the oil flowing into the machine It may further comprise. The second temperature control unit 12 serves to change the temperature of oil discharged from the oil refining unit to an operation temperature suitable for the operation of the machine, and may include cooling or heating means and temperature measuring and control means. The present invention may include any one or more of the first temperature and the second temperature control unit (11.12), each configuration can be appropriately selected by those skilled in the art as necessary. If necessary, the oil refining unit 20 may have a structure in which a separate oil heating unit (not shown) is formed.

For example, when the proper operating temperature of the lubricant operating in the machine is 90 ℃, the operating temperature of the oil in the actual machine at a specific time is 100 ℃, the appropriate refining temperature is 120 ℃ the first temperature control unit 11 Refining efficiency is heated by heating 100 oils flowing out from 120 degreeC, and the 2nd temperature control part 12 cools the 120 degreeC oil discharged | emitted from an oil refinery part to 80 degreeC, and the lubricating oil in a machine is set to the appropriate operating temperature. Allow to maintain at 90 ° C.

Hereinafter, one example will be described for specific description of the present invention, but the present invention is not limited to the following examples.

Preparation Example 1 Preparation of Carbon Nanotube-Silver Composite

0.3 g of multi-walled carbon nanotubes (Nanotech, CM-95) were put into a 500 ml round flask, and 280 ml of ethylene glycol (EG) was put into a round flask reactor. The mixture was stirred for 30 minutes, the reactor was placed in an ultrasonic cleaner, and the carbon nanotubes were dispersed in ethylene glycol for 3 hours using ultrasonic waves. At this time, the temperature of the reactor did not exceed 50 degreeC. After the sonication, the stirrer was mounted again, and a thermometer and a cooling condenser were connected. While stirring the reactor, 1.68 g of polyvinylpyrrolidone (manufactured by Fluka, average molecular weight (Mw): 40,000) and 5.6 ml of oleylamine were added thereto, followed by 1.102 g of silver nitrate (AgNO ₃ ). . A vacuum pump was connected to the reactor to remove air from the reactor and replace with nitrogen. Nitrogen was continuously added and nitrogen was allowed to flow through the inside of the reactor to prevent the inflow of oxygen. A mantle was placed in the bottom of the flask and the reactor internal temperature was raised to 200 ° C. over 40 minutes and allowed to react for 1 hour. When the reduction reaction was completed, the reactor temperature was slowly lowered to room temperature over 3 hours. The synthesized carbon nanotube-silver complex was filtered using filter paper and washed several times with ethyl acetate and hexane to obtain a carbon nanotube-silver complex. The prepared carbon nanotube-silver composite was photographed with a scanning electron microscope (SEM), and is shown in FIG. 5. It was confirmed that the silver nanoparticles were spherical and uniformly dispersed in a constant size.

Preparation Example 2 Preparation of Carbon Nanotube-Nickel Composite

0.3 g of carbon nanotubes (Hananotech, CM-95) were put into a 500 ml round flask, and 128 ml of triethylene glycol (TEG) was added to the reactor. The mixer was stirred for 30 minutes, the reactor was placed in an ultrasonic cleaner, and the carbon nanotubes were dispersed for 3 hours using ultrasonic waves. At this time, the temperature of the reactor did not exceed 50 degreeC. After the sonication, the stirrer was mounted again, and a thermometer and a cooling condenser were connected. While stirring the reactor solution, 4.26 ml of methyl polyglycol (MPG, CH ₃ (OCH ₂ CH ₂ ) nOH, n = 4-5, concentrated, MPG) was added to the flask reactor followed by 3.48 g of nickel acetylacetonate. Additionally added. A vacuum pump was connected to the reactor to remove air from the reactor and replace with nitrogen. Nitrogen was continuously added and nitrogen was allowed to flow through the inside of the reactor to prevent the inflow of oxygen. The mantle was installed at the bottom of the flask and the reactor internal temperature was raised to 280 ° C. over 1 hour and maintained for 30 minutes. When the reduction reaction was completed, the reactor temperature was slowly lowered to room temperature over 3 hours. The synthesized composite was filtered using filter paper and washed several times with ethanol to obtain a carbon nanotube-nickel composite. A scanning electron microscope (SEM) of the prepared carbon nanotube-nickel composite was shown in FIG. 6, and it was confirmed that the nickel nanoparticles were spherical and uniformly dispersed in a constant size.

Preparation Example 3 Preparation of Carbon Nanotube-Silver Nanoporous Membrane

0.34 g of carbon nanotube-silver composite prepared in Preparation Example 1, 1,000 ml of ultrapure water and 1.5 g of sodium dodecyl sulfate (SDS) were added to a 2,000 ml round flask, using ultrasonic waves at 25 to 30 ° C. Dispersion treatment for hours. The ultrasonically dispersed solution was filtered through a ceramic filter having a pore size of 0.2 μm. After the solid that failed to pass through the ceramic filter was coated on the ceramic filter, the ceramic filter was washed with 1 L of ethanol and 6 L of distilled water to wash sodium dodecyl sulfate. The amount applied per unit area after washing is 1.04 mg / cm ² . Next, the ceramic filter coated with the carbon nanotube-silver composite was coated with a porous membrane, and dried by heating at 95 ° C. for 8 hours in an oven. Next, after cooling to room temperature, the fine residue was washed with 2 L of ethanol and 6 L of ultrapure water. After the second heat treatment in an oven at 150 ° C., the silver was fused to a ceramic filter to prepare a carbon nanotube-silver composite nanoporous membrane. The surface of the prepared nanoporous membrane was photographed with a scanning electron microscope (SEM), and is shown in FIG. 7, and it was confirmed that molten silver particles were dispersed in carbon nanotubes. The porosity of the prepared nanoporous membrane was measured according to ASTM F316 method using a Capillary Flow Porometer (Model CFP-12000AEM, manufactured by Porous Materials Inc.), and the results of analysis were average pore sizes. Was measured at 54 nm.

Preparation Example 4 Preparation of Oil Filter with Carbon Nanotube-Nickel Composite Nanoporous Membrane

The carbon nanotube-nickel composite nanoparticles were prepared under the same conditions as Preparation Example 3, except that the carbon nanotube-nickel composite synthesized in Preparation Example 2 was used as the composite and the second heat treatment was performed at 260 ° C. in an oven. An oil filter with a sclera was prepared. Scanning electron microscopy (SEM) analysis of the surface of the prepared oil filter showed that the nickel particles were dispersed in the carbon nanotubes.

Example 1 Purification of Waste Lubricant Using Nanoporous Membranes

For the oil refining test of the waste lubricating oil, 2 ml of the waste lubricating oil collected at the actual auto repair shop was dissolved in 2 L of cyclohexane, and then a diluted lubricating oil was prepared. In addition, the waste lubricating oil dilution solution in which the lubricating oil was dissolved in the oil filter prepared in Preparation Example 3 was filtered to obtain a sample, and then particle size analysis was performed by a particle size analyzer (Malvern, Zeta sizer).

  8 is a result of repeating the particle size analysis of the waste lubricating oil before purification, as can be seen in Figure 8 it was confirmed that the particles of the distribution from 50 nm to 6,000 nm in the waste lubricating oil. In addition, it was confirmed that most of the particles of 100 nm size exist in the waste lubricant. When the waste lubricating oil was passed through the carbon nanotube-silver composite-coated ceramic filter (the filter used as a support in Preparation Example 3) and subjected to particle size analysis, particles having a size of 1 μm or more were filtered out. It was confirmed that the following particles were not removed.

FIG. 9 illustrates the results of repeated particle size analysis of the waste lubricant refined according to Example 1, and as shown in FIG. 9, a size of 100 nm that a general ceramic filter (MF; Micro Filter) cannot filter out. Particles and particles of at least 50 nm size were filtered, and particles of 10 nm to 20 nm size were found to remain. And the remaining 10 nm to 20 nm particles may play a role in promoting lubrication. It is reported in the literature that 50 nm size nanocarbon particles improve the friction and wear performance of lubricants (Internal Journal of Precision Engneering and Manufacturing, 2009, Vol 10, No 1, pp 85-90).

Example 2 High Temperature Waste Lubricant Purification of Nanoporous Membrane

Since the lubricating oil has a high viscosity, the purification through the nanoporous membrane filter at room temperature has a very low flow rate, so there is a problem in refining the oil. For this reason, in Example 1, a small amount was dissolved in cyclohexane to perform an oil purification experiment. In order to purify the waste lubricating oil stock, it is necessary to decrease the viscosity by increasing the temperature so that purification through the nanoporous membrane is possible. Therefore, for the oil purification test of the waste lubricating oil at high temperature, the waste lubricating oil was heated to the oil filter prepared in Preparation Example 3, and the purification experiment was performed at 70 ° C. The flow rate through the nanoporous membrane at 70 ° C. was measured at 115.8 L / m ² hr. The purified waste lubricating oil was confirmed to remove particles near 100 nm as in Example 1.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, Those skilled in the art will recognize that many modifications and variations are possible in light of the above teachings.

Accordingly, the spirit of the present invention should not be construed as being limited to the embodiments described, and all of the equivalents or equivalents of the claims, as well as the following claims, belong to the scope of the present invention .

1: metal or metal oxide
2: carbon nano structure
3: pore
10: machine with oil outlet and oil inlet
11: first temperature control unit
12: second temperature control unit
20: oil refinery
21: oil introduction pipe
22: oil discharge pipe
30: oil heating unit

Claims (20)

A method of refining an oil, comprising the steps of purifying impurities from an oil using a porous membrane in which a plurality of carbon nanostructure-metal or metal oxide complexes are bonded to each other to form pores. The method of claim 1,
The oil temperature of the refining step is at least 50 ℃, oil refining method, characterized in that less than the thermal denaturation temperature of the oil. The method of claim 1,
The oil viscosity of the refining step is an oil refining method, characterized in that 1 cP to 300 cP. The method of claim 1,
The oil refining method is an oil for automobiles, ships, insulation, gears, turbines, freezers, bearings, automatic transmissions, compressors, cutting or heat medium. The method of claim 1,
Impurity is an oil refining method, characterized in that the fine particles having a size of 20 nm or more. A plurality of carbon nanostructures-metal or metal oxide complexes have pores formed by bonding to each other, the basis weight of the complex of carbon nanostructures-metal or metal oxide is 0.05 mg / cm ² to 10 mg / cm ² for oil refining Porous membrane. The method according to claim 6,
Porous membrane for oil purification, characterized in that the porous membrane is formed on a support. The method according to claim 6,
The porous membrane for oil refining, characterized in that the pore size of the porous membrane is 10 nm to 500 nm. The method according to claim 6,
Carbon nano structure is a porous membrane for oil refining, characterized in that at least one selected from the group consisting of single-walled carbon nanotubes, double-walled carbon nanotubes, multi-walled carbon nanotubes, carbon nanohorns, carbon nanofibers, and graphene. The method according to claim 6,
Metals are Mg, Al, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Rb, Sr, Y, Zr, Mo, Ru, Rh, Pd, Ag, Cd, In, Sn, Cs, Ba, La, Ce, Nd, Sm, Eu, Gd, Tb, Hf, Ir, Pt, Tl, Pb and Bi at least one selected from the group consisting of Sclera. An oil introduction pipe into which oil is introduced;
An oil refining unit including a porous membrane containing a complex of carbon nanostructure-metal or metal oxide for refining the oil introduced from the oil inlet tube;
An oil discharge pipe for discharging the purified oil from the oil refining unit; And
Oil refining apparatus including an oil heating unit for heating the oil. The method of claim 11,
Porous membrane is an oil refining apparatus, characterized in that the metal or metal oxide has a network structure by connecting the carbon nanostructure. The method of claim 11,
Oil pore size of the porous membrane is characterized in that 10 nm to 500 nm. The method of claim 11,
An oil refining apparatus, wherein the oil heating unit is formed in at least one of an oil inlet tube and an oil refining unit. The method of claim 11,
Oil refining apparatus is formed in the oil discharge pipe, further comprising an oil cooling unit for cooling the discharged oil. A machine having an oil outlet and an oil inlet;
An oil introduction pipe fluidly connected to the oil outlet and introducing oil flowing out of the machine into an oil refining unit;
An oil refining unit including a porous membrane containing a complex of carbon nanostructure-metal or metal oxide for refining the oil introduced from the oil inlet tube; And
And an oil discharge pipe fluidly connected to the oil inlet to introduce the oil refined in the oil refining unit into the machine. 17. The method of claim 16,
An oil refining system, further comprising an oil heating unit formed in the oil refining unit. 17. The method of claim 16,
The porous membrane is an oil refining system, characterized in that the metal or metal oxide has a network structure by connecting the carbon nanostructure. 17. The method of claim 16,
An oil purification system, characterized in that the pore size of the porous membrane is 10 nm to 500 nm. 17. The method of claim 16,
A first temperature controller formed at an oil introduction pipe or an oil refining unit to control a temperature of oil flowing out of the machine; And
Oil refining system further comprises any one or more of the second temperature control portion formed in the oil discharge pipe, for controlling the temperature of the oil flowing into the machine.

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