CN115475451A

CN115475451A - Method and system for purifying oil

Info

Publication number: CN115475451A
Application number: CN202110598436.5A
Authority: CN
Inventors: 仇春杰; 张国江; 黄峰峰; 韩波; T.珀森; G.登波
Original assignee: SKF AB; SKF Recondoil AB
Current assignee: SKF AB; SKF Recondoil AB
Priority date: 2021-05-31
Filing date: 2021-05-31
Publication date: 2022-12-16
Also published as: WO2022253590A1

Abstract

Method and system for cleaning oil, wherein the method comprises at least two cleaning steps, wherein the at least two cleaning steps comprise: a particle charging step (S3) comprising treating the oil to be purified in a particle charging unit (6), whereby some particles are positively charged and some particles are negatively charged in the particle charging unit (6); and a chemical step (S3 ') comprising adding (S3 ' a) a separation aid to the oil to be purified and dispersing (S3 ' b) the separation aid into the oil to be purified.

Description

Method and system for purifying oil

Technical Field

The invention relates to a method and a system for purifying oil.

Background

The purification of contaminated mineral and synthetic based industrial oils such as lubricating oils, honing oils, rolling oils, gearbox oils, quenching oils, processing oils, hydraulic oils or pre-treated waste oils is important for the possibility of using/reusing these oils and is therefore also an important factor for the future environment and the limited natural resources of the oils. These oils play important roles in, for example, lubrication, vibration absorption, heat dissipation, rust prevention, and extension of the mechanical service life of vehicles, ships, and machining equipment. During use of e.g. lubricating oil, the amount of contaminant particles in the oil will increase, which will increase friction and shorten the life of the equipment. The oil can be purified in different ways. Gravity settling and filtration are common purification methods. However, small particles are difficult to remove. Coagulant flocculation is also sometimes used in conjunction with gravity settling for oil purification. In some examples, contaminated oil is purified or recovered by a liquid two-phase separation process in which a liquid separation aid is added to and mixed with the oil. The impurities will be captured by the separation aid and accumulate in the bottom phase.

In WO2018/199837, a method and system for purifying oil is disclosed, wherein a separation aid is used, and a filtration step for purifying oil is also provided.

Due to the high viscosity of the oil, small particles are often difficult to remove, and gravity settling after flocculation is sometimes very slow. Filtration requires a large number of filter elements. The purification efficiency may be low. For some processes, such as distillation and dehydration, the energy consumption can be significant.

There is a need for an improved purification process for contaminated oils.

Disclosure of Invention

It is an object of the present invention to provide an improved method and system for cleaning oil.

It is another object of the present invention to provide a method and a system for cleaning oil, wherein small contaminating particles are effectively removed.

This is achieved in a method and a system according to the independent claims.

According to an aspect of the present invention, a method for purifying oil is provided, wherein the method comprises at least two purification steps, wherein the at least two purification steps comprise:

-a particle charging step comprising treating the oil to be purified in a particle charging unit, whereby in the particle charging unit (6) some particles are positively charged and some particles are negatively charged; and

a chemical step comprising adding a separation aid to the oil to be purified and dispersing the separation aid into the oil to be purified, wherein the separation aid is liquid at the temperature at which the process is carried out and will adsorb/absorb contaminating solids and/or dissolved impurities in the oil to be purified by chemical interaction, and wherein the separation aid composition is substantially insoluble in the oil to be purified due to its polarity, forming a two-phase mixture when mixed with the oil to be purified.

According to another aspect of the present invention, there is provided a system for purifying oil, the system comprising:

-a particle charging unit, in which the oil to be purified in the system can be received and treated, whereby in the particle charging unit (6) some particles are positively charged and some particles are negatively charged; and

-a chemical treatment section comprising:

o a separation aid dosing device comprising a separation aid, wherein the separation aid is liquid at the temperature at which the process is carried out and will adsorb contaminating solids and/or dissolved impurities in the oil to be purified by chemical interaction, and wherein the separation aid composition is substantially insoluble in the oil to be purified due to its polarity, forms a two-phase mixture when mixed with the oil to be purified, and wherein the density of the separation aid is different from the density of the oil to be purified; and

a dispersion unit fluidly connected to the separation aid dosing device for receiving the separation aid, and connected in a system for receiving the oil to be purified, and configured for dispersing the separation aid into the oil to be purified.

Thus, an efficient method and system for purifying oil is provided. By combining the use of a liquid separation aid for the liquid two-phase separation process with the treatment of the oil in the particle charging unit, an efficient process is achieved, which is also effective for removing very small particles. The process according to the invention is time-saving. For example, the settling process is very time consuming. In a particle charging unit, some particles will be positively charged and some will be negatively charged, after which they will attract each other and combine into larger particles or aggregates. Thus, small particles will aggregate into larger particle aggregates and possibly into droplets of separation aid, whereby subsequent sedimentation and/or filtration and/or centrifugation will be faster and/or more efficient. Sedimentation after use of the separation aid according to the invention can be time consuming, especially for high viscosity oils. By combining with the particle charging technique according to the invention, the particles will aggregate into larger particle aggregates and the possible sedimentation step will then be faster and more efficient. In some examples of the invention, filtration and/or centrifugation is provided in place of or in addition to the sedimentation step. However, when the use of a separation aid is combined with a particle charging step, filtration and centrifugation will also be more efficient, as larger particle aggregates are easier to pass through the filter and separate in the centrifuge than small particles. The present invention will significantly accelerate the purification process. Thus, a higher flow rate can be provided through the system, which is suitable for overall process efficiency. Furthermore, when the process is combined with a particle charging step, a smaller amount of separation aid may be required.

In some embodiments of the invention, the at least two purification steps further comprise a subsequent separation step comprising separating the oil to be purified in a separation device, wherein the subsequent separation step is performed after the particle charging step and the chemical step. The separation device is located in the system such that the oil to be purified is first treated in the particle charging unit and the dispersion unit and then transported to the separation device comprising a filter and/or a centrifuge and/or a settling tank. The subsequent separation step will be very efficient due to the combined effect of the particle charging technique and the separation aid with which the oil has been treated.

In some embodiments of the invention, the chemical step is performed before the particle charging step, wherein a dispersion unit is provided between the at least one supply tank provided in the system containing the contaminated oil to be purified and the particle charging unit, such that the oil to be purified transferred from the at least one supply tank to the particle charging unit will first pass the dispersion unit.

In some embodiments of the invention, the chemical step is performed after the particle charging step, wherein the dispersion unit is arranged in fluid connection with an outlet of the particle charging unit, such that the oil to be purified, which has been treated in the particle charging unit, is transferred for further chemical treatment in the dispersion unit.

In some embodiments of the invention, the method further comprises analyzing the contamination level of the oil that has been purified by the method, and possibly redirecting the oil to a previous purification step depending on the analyzed contamination level. Thus, in some embodiments, the system comprises an analysis device, which is located in the system such that it can analyze the degree of contamination of the oil that has been purified in the system; and a redirecting device configured such that it can redirect oil that has been purified in the system for further purification in the system according to the analyzed contamination level.

Drawings

FIG. 1a is a flow chart of a method according to an example of the invention.

FIG. 1b is a flow chart of a method according to an example of the invention.

Figure 2a schematically shows a system according to an example of the invention.

Figure 2b schematically shows a system according to an example of the invention.

Detailed Description

Contaminated mineral and synthetic-based industrial oils, such as lubricating oils, honing oils, rolling oils, gearbox oils, quenching oils, processing oils, hydraulic oils or pre-treated waste oils, can be purified by the method and system according to the invention. During use of e.g. lubricating oil, the amount of contaminant particles in the oil will increase, which will increase friction and shorten the life of the equipment. According to the invention, the oil can be purified separately, i.e. in its entirety, batchwise or continuously during use in a purification system connected to the apparatus in which the oil is used. Thus, the system according to the invention can be directly connected to a device using, for example, lubricating oil or another industrial oil for continuous overall cleaning, or the system can be separately located and cleaned of contaminated oil in batches.

The invention will first be described in general with reference to all the figures. Fig. 1a and 1b show a flow chart of two examples of the method according to the invention, and fig. 2a and 2b schematically show two examples of the system according to the invention.

Methods and

systems

10a, 10b for purifying oil are provided. An initial method step S1 of providing the oil to be purified to the

purification system

10a, 10b is first provided. According to the invention, the method also comprises at least two purification steps, denoted S3 and S3'. The at least two purification steps include a particle charging step S3 and a chemical step S3':

s3: the particle charging step comprises treating the oil to be purified in a particle charging unit. In the particle charging unit according to the invention, the particles and possibly also the droplets are charged. Some particles are positively charged and some are negatively charged. The oppositely charged particles will then attract each other and combine into larger particles, also called aggregates, which may also include separation aid droplets. One example of such a particle charging unit is a balanced charge agglomeration BCA unit, in which the primary media stream is split into two streams, one carrying a net positive charge and the other a net negative charge when flowing past the electrodes. Thereafter, the positive and negative flows recombine, and the positively and negatively charged particles will attract each other and will form larger aggregates.

And S3': the chemical step comprises at least two substeps:

s3' a: adding a separation aid to the oil to be purified, and

s3' b: the separation aid is dispersed into the oil to be purified. The dispersing step S3' b may be combined with the adding step S3' a if the adding step S3' a is provided, for example, via a nozzle through which the separation aid is sprayed into the oil to be purified, or if the separation aid is pushed/forced into the oil to be purified, for example, through a membrane. In order to optimize the effect of the separation aid and to increase the efficiency, the separation aid may be provided into the oil to be purified (e.g. via a nozzle or a membrane) in a controlled droplet size. The dispersion can also be a mixing of the separation aid with the oil to be purified in a mixing device, for example a mixer comprising a stirring mechanism or a rotor-stator mixer or a static mixer or an in-line static line mixer. Mixing may also be provided by a pump.

According to the invention, the particle charging step S3 and the chemical step S3' can be carried out in any order. In fig. 1a and 2a, an example of a method and system is shown, wherein a chemical step S3' is performed before performing a particle charging step S3. In fig. 1b and 2b, an example of a method and system is shown, wherein a chemical step S3' is performed after performing the particle charging step S3.

By combining this chemical purification with a liquid separation aid with treatment in a particle charging unit, a very efficient oil purification is achieved. The purification is effective because very small particles will also be effectively removed by a combination of two different types of aggregation techniques, one being a chemical technique using a liquid separation aid and the other being a physical technique using particle charging. The cleaning is also effective in terms of the time taken for cleaning, since the particle charging process will combine the particles into larger particle aggregates, which will speed up the possible next cleaning step. If the separation aid is added before the particle charging step, the separation aid droplets with adsorbed/absorbed contaminant particles can also be combined in the particle charging unit into separation aid droplets and larger aggregates of contaminant particles. For example, if sedimentation is the next step of purification, this will be accelerated since larger particle aggregates and/or larger droplets will settle faster than smaller particles and smaller droplets, which will also be more efficient if centrifugation is used as the next step of purification, since larger particle aggregates and larger droplets are easier to remove in the centrifuge. Larger particle aggregates and separation aid droplets with adsorbed/absorbed contaminating particles are removed more efficiently by the filter if the filtration step is used as the next purification step.

According to the invention, the

system

10a, 10b for cleaning oil comprises a chemical treatment section 15 and a particle charging unit 6, wherein the oil to be cleaned in the system can be received and treated. The chemical treatment section 15 comprises a separation aid dosing device 1 and a dispersion unit 5 fluidly connected to the separation aid dosing device 1. The separation aid dosing device 1 comprises a separation aid, from which the dispersing unit 5 receives the separation aid from the separation aid dosing device 1. A dispersion unit 5 is further connected in the

system

10a, 10b for receiving the oil to be purified. The dispersing unit 5 is configured for dispersing the separation aid into the oil to be purified.

The separation aid is liquid at the temperature at which the process is carried out and will adsorb/absorb by chemical interaction contaminating solids and/or dissolved impurities in the oil to be purified. The separation aid composition is substantially insoluble in the oil to be purified due to its polarity, and forms a two-phase mixture when mixed with the oil to be purified. In some embodiments, the density of the separation aid may be different from the density of the oil to be purified.

The use of separation aids (also known as chemical enhancers) to capture contaminants/impurities in contaminated oils has been previously described, see for example WO2018/199839. A liquid separation aid is added to and mixed with the oil and impurities in the oil will be captured by the separation aid. The separation aid is substantially insoluble in the oil, forms a two-phase mixture upon mixing, and attracts impurities in the oil during mixing of the oil and the separation aid. The separation aid will adsorb/absorb contaminating solids and/or dissolved impurities in the contaminated target oil through chemical interaction. The separation aid should be liquid at the temperature at which the process is carried out. The separation aid composition should be substantially insoluble in the contaminated target oil and form a two-phase mixture when mixed with the contaminated oil. The density of the liquid separation aid may also be different from the density of the contaminated oil to be purified.

The separation aid is insoluble in the contaminated target oil due to its polarity, and therefore a colloid consisting of small droplets of the liquid separation aid composition is formed by stirring, which can adsorb unwanted solids or dissolved impurities in the contaminated target oil through chemical interactions (hydrophilic, hydrophobic and charge interactions). In case the separation aid has a higher density than the oil, the separation aid will form a lower phase together with the solids and/or dissolved impurities under gravity separation. In case the separation aid has a density lower than the contaminated target oil, it will form an upper phase upon gravity separation.

The liquid separation aid used in the present invention may be prepared based on the following ingredients: a) A polar polymer; b) Hydrotropes/solubilizers; and c) a co-surfactant.

Suitable separation aids having the above properties that can be used in the process of the present invention may for example constitute compositions comprising a mixture of polar polymers, such as polyethylene glycol, polypropylene glycol or similar polyalkylene glycols, organic surface-active ingredients having nonionic, anionic, cationic and amphoteric properties, capable of increasing the solubility of solid or dissolved impurities in the separation aid.

One example of a separation aid useful in the present invention includes: a) At least one polar polymer insoluble in oil and having a density higher than that of oil, such as polyethylene glycol having an average molecular weight of 190-210 g/mole, for example Carbowax PEG 200 (dow chemical company); b) At least one surface active hydrotrope/solubilizer, such AS an anionic sulfonic acid, phosphate-based species, or a multi-glycoside nonionic surfactant, such AS simulsol SL4, simulsol SL7G, and simulsol AS48 (Sepic, liquefied air mass); c) At least one amphoteric co-surfactant, such as a propionate type, for example, ampholak YJH-40 (Akzo Nobel), which is sodium caprylamido dipropionate.

In some examples of the invention, but not necessarily, the at least two purification steps of the method further comprise a subsequent separation step S5. The subsequent separation step comprises separating the oil to be purified in a subsequent separation device 7. The separation device 7 may for example comprise one or more settling tanks, a filtration device and/or a centrifugation device. This subsequent separation step S5 is performed after the particle charging step S3 and the chemical step S3'. The separating device 7 is located in the

system

10a, 10b such that the oil to be purified is first treated in the particle charging unit 6 and the dispersion unit 5 and then transported to the separating device 7.

In some examples of the invention, but not necessarily, the method further comprises step S6: the oil that has been purified in the system, also called purified oil, is analyzed and it is determined whether further purification is required on the basis of said analysis. If further purification is required, the method may comprise step S7: the cleaned oil is redirected back to the previous step in the cleaning process. This may be a redirect to any previous step. Thus, the

system

10a, 10b may comprise some kind of analyzing device 12, such as a sensor 12, and redirecting means 13, so that the purified oil can be redirected back to the previous part of the system, e.g. the dispersion unit 5 or the particle charging unit 6. The analysis device 12 may be connected in fluid communication with the outlet 7b of the separation apparatus 7. The redirecting means 13 is only schematically indicated in fig. 2b by dashed redirecting arrows. However, such redirecting means 13 comprise a fluid connection 13a which is in fluid connection with the outlet 7b of the separating means 7 and with, for example, the inlet 6a of the particle charging unit and/or the inlet 5a of the dispersing unit 5. The redirecting arrangement 13 further comprises one or more valves 13b and a control system 13c, which are connected to the one or more valves 13b and the analysis device 12, so that the redirecting of the cleaned oil can be performed on the basis of the analysis result of the cleaned oil. The contamination level of the purified oil can be measured, for example, by the analysis device 12.

The

system

10a, 10b also suitably comprises a feed tank 2 containing the oil to be purified. The system further comprises one or more pumps for pumping the oil to be cleaned from the supply tank 2 into the

system

10a, 10b for cleaning and for pumping the separation aid from the separation aid dosing device 1 into the system. In the example shown in fig. 2a and 2b, a separation aid pump 3 is provided for pumping separation aid from the separation aid dosing device 1 into the dispersing device 5, and an oil pump 4 is provided for pumping contaminated oil from the supply tank 2 first to the dispersing device 5 (fig. 2 a) and then to the particle charging unit 6, or first to the particle charging unit 6 and then to the dispersing device 5 (fig. 2 b).

The example disclosed in fig. 1a and 2a will now be described in further detail. In this example, the separation aid is added to the oil to be purified before the oil is provided to the particle charging unit 6 together with the separation aid. The separation aid dosing device 1 is thus fluidly connected to the dispersion unit 5 via a pump 3 by means of a fluid line 101, and the supply tank 2 with the oil to be purified is fluidly connected to the dispersion unit 5 via a pump 4 by means of a fluid line 102. Alternatively, the separation aid dosing device 1 may be fluidly connected to a fluid line 102 connecting the feed tank 2 with the dispersion unit 5, whereby the separation aid is added to the oil to be purified in the fluid line 102. The dispersing unit 5 is configured to disperse the separation aid into the oil to be purified as described above. The dispersion unit 5 may for example comprise a mixing device. The dispersing unit 5 can also be configured such that the separation aid can be added via, for example, a pump, a static mixer, a membrane or via a nozzle. Thus, the separation aid can be added to the oil to be purified in the form of small droplets, which will result in a larger specific surface area and will increase the adsorption efficiency for adsorbing impurities. The separation aid will attract impurities in the oil to be purified, forming aggregates of separation aid droplets (also called floes) together with the impurity particles. The oil to be purified together with the separation aid will subsequently be transferred to the particle charging unit 6. In a particle charging unit, some particles are positively charged and some particles are negatively charged. The oppositely charged particles will then attract each other and combine into larger particles, also called aggregates, which may also include separation aid droplets. One example of such a particle charging unit is a balanced charge agglomeration BCA unit, where the primary media stream is split into two streams, one stream carrying a net positive charge and the other stream carrying a net negative charge when flowing past the electrodes. Thereafter, the positive and negative flows recombine, the positively and negatively charged particles and particle aggregates and/or separation aid droplets will attract each other and larger aggregates will be formed in the particle charging unit. These larger particle aggregates and separation aid droplets will increase the purification efficiency. The purification quality and purification speed can be improved. Due to the use of the separation aid and particle charging technique according to the invention, even very small contaminating particles in the oil to be purified can be effectively separated from the oil. Furthermore, the next purification step provided in the separation device 7 of fig. 2a can be both accelerated and more efficient due to the larger particle aggregates and the separation aid droplets. If the separation device 7 is a settling tank or centrifuge, the separation of the sludge phase will be faster due to the higher density difference of the larger sized aggregates and the oil. Otherwise, such a settling/separation step can be very time consuming, especially for high viscosity oils. If the separation device 7 is a filter, this step will also be more efficient as larger aggregates are more efficiently separated in the filter. Since the present invention combines the separation aid with the charging of the particles, there will be a very small amount of small impurity particles in the oil to be purified when it reaches the appropriate separation device 7. The smallest particles are often difficult to separate in centrifuges and filters. The separation device 7 may be fluidly connected to the outlet 6b of the particle charging unit 6 by a pump 9. However, the pump 9 may be omitted. Other units may also be provided in the system, such as pumps, valves, tanks and filters. For example, as shown in fig. 2b, a pre-filter may be used before the particle charging unit 6.

The example disclosed in fig. 1b and 2b will now be described in further detail. In this example, the separation aid is added to the oil to be purified after the oil to be purified has been treated in the particle charging unit 6. The feed tank 2 with the oil to be purified is connected to the inlet 6a of the particle charging unit 6 by means of a pump 4. In the example shown in fig. 2b, but not necessarily, a pre-filter device 11 is arranged between the supply tank 2 and the particle charging unit 6, so that the oil to be purified, which is transferred from the supply tank 2 to the particle charging unit 6, will pass the pre-filter device 11 on its way to the particle charging unit 6. The pre-filter means 11 comprises some kind of filter that will filter out larger impurities from the oil to be purified and act to prevent clogging/damage of the particle charging unit. In the example shown in fig. 2a, the pre-filtering means 11 may also be provided before the particle charging unit, even if it is not shown in fig. 2 a. In a particle charging unit, the primary medium flow is divided into two streams, one stream carrying a net positive charge and the other stream carrying a net negative charge as it flows past the electrodes. Thereafter, the positive and negative currents recombine, the positively and negatively charged particles and particle aggregates will attract each other and larger particle aggregates will be formed in the particle charging unit. Thus, when transferred out of the particle charging unit 6, the oil to be purified comprises aggregates of impurity particles and a smaller amount of small impurity particles than before the particle charging unit 6. The dispersion unit 5 is connected to the outlet 6b of the particle charging unit 6, whereby the oil to be purified is transferred to the dispersion unit 5 after treatment in the particle charging unit 6. The separation aid dosing device 1 is connected to the dispersion unit 5 by means of a pump 3, whereby the separation aid provided in the separation aid dosing device 1 can be provided to the dispersion unit 5 and the oil to be purified as described above. The dispersion unit may comprise, for example, a mixing device and/or a nozzle and/or another mixing function as described above in relation to the example shown in fig. 2a, by means of which the separation aid can be effectively dispersed into the oil. As described in more detail above, the separation aid according to the invention will effectively attract impurity particles and particle aggregates in the oil to be purified. The combined effect of the treatment in the particle charging unit 6 and the use of a liquid separation aid will effectively collect impurities in the oil to be purified. Aggregates of impurity particles and separation aid droplets will be formed, which can be easily and efficiently separated out in the subsequent separation step of the above-described method. I.e. in the separating device 7 which may be connected to the outlet 5b of the dispersing unit 5 by means of a pump 9. However, the pump 9 may not be required. As mentioned above, the separation device 7 may be, for example, a settling tank, a filter or a centrifuge or one or more of them.

Claims

1. A method for purifying oil, wherein the method comprises at least two purification steps, wherein the at least two purification steps comprise:

-a particle charging step (S3) comprising treating the oil to be purified in a particle charging unit (6), whereby in the particle charging unit (6) some particles are positively charged and some particles are negatively charged; and

-a chemical step (S3 ') comprising adding (S3 ' a) a separation aid to the oil to be purified and dispersing (S3 ' b) the separation aid into the oil to be purified, wherein the separation aid is liquid at the temperature at which the process is carried out and will adsorb/absorb contaminating solids and/or dissolved impurities in the oil to be purified by chemical interaction, and wherein the separation aid composition is substantially insoluble in the oil to be purified due to its polarity, forming a two-phase mixture when mixed with the oil to be purified.

2. The method according to claim 1, wherein the at least two purification steps further comprise a subsequent separation step (S5) comprising separating the oil to be purified in a separation device (7), wherein the subsequent separation step (S5) is performed after the particle charging step (S3) and the chemical step (S3').

3. The method according to claim 1 or 2, wherein said chemical step (S3') is carried out before said particle charging step (S3).

4. The method according to claim 1 or 2, wherein said chemical step (S3') is carried out after said particle charging step (S3).

5. Method according to any of the preceding claims, wherein the method further comprises analyzing (S6) the degree of contamination of the oil that has been purified by the method, and possibly redirecting (S7) the oil to a previous purification step depending on the analyzed degree of contamination.

6. A system for purifying oil, the system comprising:

-a particle charging unit (6) in which the oil to be purified in the system can be received and treated, whereby in the particle charging unit (6) some particles are positively charged and some particles are negatively charged; and

-a chemical treatment section (15) comprising:

-a separation aid dosing device (1) comprising a separation aid, wherein the separation aid is liquid at the temperature at which the process is carried out and will adsorb contaminating solids and/or dissolved impurities in the oil to be purified by chemical interaction, and wherein the separation aid composition is substantially insoluble in the oil to be purified due to its polarity, forms a two-phase mixture when mixed with the oil to be purified, and wherein the density of the separation aid is different from the density of the oil to be purified; and

-a dispersion unit (5), which is fluidly connected to the separation aid dosing device (1) for receiving the separation aid, and which is connected in a system for receiving the oil to be purified, and which is configured for dispersing the separation aid into the oil to be purified.

7. The system according to claim 6, further comprising at least one supply tank (2), in which supply tank (2) the oil to be purified is provided, wherein the particle charging unit (6) and the dispersion unit (5) are in fluid connection with the at least one supply tank (2) for receiving the oil to be purified.

8. A system according to any of claims 6-7, wherein the dispersion unit (5) is arranged between the at least one supply tank (2) and the particle charging unit (6) such that the oil to be purified transferred from the at least one supply tank (2) to the particle charging unit (6) will first pass the dispersion unit (5).

9. A system according to any of claims 6-7, wherein the dispersion unit (5) is arranged in fluid connection with the outlet (6 b) of the particle charging unit (6) so that the oil to be cleaned, which has been treated in the particle charging unit (6), is transferred for further chemical treatment in the dispersion unit (5).

10. A system according to any of claims 6-9, wherein the system further comprises a subsequent separation device (7), which subsequent separation device (7) is positioned in the system such that the oil to be purified is first treated in the particle charging unit (6) and the dispersion unit (5) and then transported to the separation device (7) comprising a filter and/or a centrifuge and/or a settling tank.

11. The system of any of claims 6-10, further comprising: an analysis device (12), the analysis device (12) being located in the system such that it can analyze the degree of contamination of the oil that has been purified in the system; and a redirecting device (13), the redirecting device (13) being configured such that it can redirect oil that has been purified in the system for further purification in the system according to the analyzed degree of contamination.

12. The system according to any of claims 6-11, wherein the particle charging unit (6) is a balanced charge agglomeration unit.