CN113336402B

CN113336402B - Formulation composition for recovering oil from oily sludge, recovery process and apparatus

Info

Publication number: CN113336402B
Application number: CN202110625213.3A
Authority: CN
Inventors: 朱南文; 王晓宁; 袁海平; 沈雁文
Original assignee: Shanghai Jiaotong University
Current assignee: Shanghai Jiaotong University
Priority date: 2021-06-04
Filing date: 2021-06-04
Publication date: 2022-11-08
Anticipated expiration: 2041-06-04
Also published as: CN113336402A

Abstract

The present application relates to a formulation composition, a recovery process and an apparatus for recovering oil from oil-containing sludge. The formulation compositions of the present application comprise acetonitrile, ethyl acetate, ketones. The treatment method of the oily sludge comprises the steps of mixing the preparation composition with the oily sludge to obtain oily turbid liquid, obtaining solid-phase sediment and liquid phase through mechanical separation, evaporating the liquid phase at the temperature of 80-95 ℃, and primarily separating the preparation composition from the liquid phase to obtain the preparation composition and an oil-water mixture, wherein the preparation composition is reused in the treatment process of the oily sludge, and the oil-water mixture is separated by a conventional method. The oily sludge treatment equipment comprises a stirring device, a solid-liquid separation device, a mixing device, an evaporation device and a recovery device.

Description

Formulation composition for recovering oil from oily sludge, recovery process and apparatus

Technical Field

The application belongs to the technical field of environmental engineering and relates to treatment of oily sludge. More particularly, the present application relates to formulation compositions for recovering oil from oily sludge, and also relates to processes and apparatus for recovering oil from oily sludge.

Background

The oily sludge is a main pollutant generated in the processes of petroleum exploitation, gathering and transportation, refining, sewage treatment and the like, has extremely complex composition components, contains a plurality of oily components such as crude oil, paraffin, asphaltene and the like, also contains a large amount of chemical additives and various toxic and harmful substances such as bacteria, heavy metals, inorganic salts, benzene series, phenols, anthracene, pyrene and the like which are added in the processes of extraction, transportation and production, and can endanger the environmental safety if the oily sludge is directly discarded into the environment without proper treatment. Because the oily sludge has high harmfulness, the oily sludge is definitely classified as dangerous solid waste in national records of dangerous wastes.

In order to prevent the oily sludge from polluting the environment and improve the recovery and utilization rate of crude oil, the technical specification of waste mineral oil recovery and utilization pollution control (HJ 607-2011) formulated in China in 2011 is explicitly proposed: oil-containing sludge with oil-containing sludge content of more than 5% and oil-containing silt should be recycled, the oil content of the oil-containing silt after oil-sand separation should be less than 2%, the oil content of the oil-containing rock debris after oil debris separation should be less than 5%, and the separated rock debris should be incinerated; the technical policy of pollution control in the oil and gas exploitation industry implemented in 2012 is as follows: the oil substances in crude oil falling to the ground, oil sludge (sand) generated by crude oil treatment and wastewater treatment and the like are required to be recovered, and the resource utilization rate of the oil-containing sludge is required to be more than 90%; according to 'oil-containing sludge disposal utilization control restriction' (DB 61/T1025-2016) of Shaanxi province local standard of quality and technology supervision administration of Shaanxi province in 2016, the oil-containing sludge can be used for laying oil well sites and grade roads after the oil content is reduced to 1% and the water content is reduced to 40%; by 2020, the ecological environment bureau of Daqing city requires the treatment requirement of oil field upgrading oily sludge, and the petroleum content of sludge discharged into the environment after treatment cannot exceed 0.3 percent. Therefore, the treatment of the oily sludge in various regions of China is very important. However, the annual production of oil-containing sludge currently in China exceeds 500 ten thousand tons, and the economic cost of treatment and disposal is huge under the condition of lacking of a treatment technology with low operation cost.

The treatment method for reducing the oil content in the oily sludge and realizing resource utilization mainly comprises methods such as a chemical hot washing method, an ultrasonic treatment method, a mechanical-tempering separation method, a solvent extraction method, an incineration method, a pyrolysis method and the like, however, in popularization and application, various existing treatment methods have various defects, for example, the chemical hot washing method can generate wastewater with high treatment difficulty, and the oily sludge is generated in the wastewater treatment process; after the treatment by an ultrasonic method and a mechanical-tempering separation method, the oil content in the sediment is still high, and the current emission treatment requirements are difficult to meet; the incineration, pyrolysis and other thermochemical treatment methods have high energy consumption and poor economy; although the treatment cost of the solvent method is lower than that of the thermochemical treatment method, the mineral oil extracted by the solvents such as petroleum ether, gasoline, carbon tetrachloride, toluene and the like proposed in the current research has higher mineral oil and solvent residues in the sediments, and the sediments are difficult to meet the relevant emission treatment requirements.

Heretofore, there has been no method in the art that can efficiently recover oils, such as mineral oil, from oily sludge at low cost. Furthermore, there is a pressing need in the art for formulations for the efficient recovery of oils, such as mineral oil, from oily sludges in a cost-effective manner, as well as related recovery processes and equipment used.

Disclosure of Invention

Aiming at the defects of the existing oily sludge resource utilization technology, the oily sludge with high heavy oil content, such as oil tank bottom sludge, oily sludge generated by an oily wastewater treatment plant and the like, is taken as a treatment object, and the preparation composition which can efficiently recover mineral oil from the oily sludge and can ensure that the oil content in sediments after the oily sludge is treated is lower than 0.3 percent is provided. The present application also provides a process for treating oil-containing sludge to recover oil from the oil-containing sludge. The present application also provides an apparatus for treating oily sludge to recover oil from the oily sludge.

In particular, a first aspect of the present application relates to a formulation composition comprising acetonitrile, ethyl acetate, ketones.

In one embodiment of the first aspect, the acetonitrile is 10 to 60 volume parts, the ethyl acetate is 5 to 20 volume parts, and the ketones are 20 to 80 volume parts. In another embodiment of the first aspect, the acetonitrile is 40 to 60 parts by volume, the ethyl acetate is 10 to 20 parts by volume, and the ketones are 20 to 40 parts by volume. In another embodiment of the first aspect, the acetonitrile is 60 parts by volume, the ethyl acetate is 20 parts by volume, and the ketones are 20 to 30 parts by volume. In another embodiment of the first aspect, the ketone comprises acetone or butanone.

A second aspect of the present application relates to a formulation composition, a method for treatment of oily sludge comprising the steps of:

(1) Providing a formulation composition comprising acetonitrile, ethyl acetate, ketones;

(2) Adding the oily sludge into the preparation composition according to the dry weight of the sludge in the oily sludge, and fully and uniformly mixing to form oily turbid liquid;

(3) Carrying out solid-liquid separation on oil-containing turbid liquid by adopting a solid-liquid separator to form two parts, namely solid-phase sediment and a liquid phase, wherein the liquid phase comprises oil, water and a preparation composition;

(4) Adding the solid-phase sediments into the preparation composition prepared according to the step (1) again, and forming a liquid phase and a solid-phase sediments by adopting the solid-liquid separator again;

(5) Repeating the step (4) until the oil content of the obtained solid phase sediment is lower than a specified value;

(6) Collecting the liquid phase obtained in step (4) and/or (5), adding the liquid phase into an evaporator for evaporation treatment, and separating the preparation composition and the oil-water mixture from the liquid phase;

(7) Optionally, the oil-water mixture is separated to obtain separated oil and water.

In one embodiment of the second aspect, step (4) is repeated 5-10 times. In another embodiment of the second aspect, step (4) is repeated 6-9 times. In another embodiment of the second aspect, the concentration of the oily sludge (on a dry basis) in the oily sludge of step (2) is from 50 to 500g/L. In another embodiment of the second aspect, the stated value is 0.3 wt.% or 0.1 wt.%. In another embodiment of the second aspect, step (2) lasts more than 20 minutes. In another embodiment of the second aspect, the formulation composition formed in step (6) is recovered for reuse in step (2).

The third aspect of the present application relates to an oil-containing sludge treatment apparatus, which includes a stirring device, a mixing device, a solid-liquid separator, an evaporation device, and a recovery device, wherein:

(1) Providing a formulation composition comprising acetonitrile, ethyl acetate, ketones in a stirring device;

(2) In the mixing device, forming oily turbid liquid by mixing the oily sludge and the preparation composition obtained in the stirring device;

(3) Separating to obtain a liquid phase and a solid phase sediment in a solid-liquid separator;

(4) Evaporating the liquid phase in an evaporator to separate the preparation composition and the oil-water mixture from the liquid phase;

(5) In the recovery unit, the oil-water mixture is separated to obtain separated oil and water.

In an embodiment of the third aspect, the solid liquid separator is a gravity settling tank. In another embodiment of the third aspect, the temperature of the evaporator is 80-95 ℃.

The above aspects and embodiments of the present application may be combined in any form. For example, the formulation composition of the first aspect may be used in the method of the second aspect and the device of the third aspect. For example, the method of the second aspect may be carried out by the apparatus of the third aspect or employ the formulation composition of the first aspect. For another example, the device of the third aspect may employ the formulation composition of the first aspect or perform the method of the second aspect.

Drawings

FIG. 1 is a process flow diagram of the present application.

Fig. 2 is a process effect diagram according to the embodiment of the present application.

FIG. 3 is a graph comparing the treatment effects of examples of the present application and comparative examples.

Detailed Description

The present application is further described below in conjunction with the appended drawings, but it should be understood that they are merely illustrative of the present application and are not intended to limit the scope of the present application.

1. Formulation composition

The formulation composition may comprise or consist of acetonitrile, ethyl acetate, ketones. For ketones in the formulation composition, they may comprise, consist of, or consist of acetone or butanone. For example, the formulation composition may comprise: 1) Acetonitrile, ethyl acetate, acetone; 2) Acetonitrile, ethyl acetate, butanone. For another example, the formulation composition may be composed of: 1) Acetonitrile, ethyl acetate, acetone; 2) Acetonitrile, ethyl acetate, butanone.

For a formulation composition, the acetonitrile content can be 10-60 parts by volume, 20-60 parts by volume, 30-60 parts by volume, 40-60 parts by volume, 50-60 parts by volume, 15-55 parts by volume, 20-50 parts by volume, 25-45 parts by volume, 30-40 parts by volume, 10 parts by volume, 15 parts by volume, 20 parts by volume, 25 parts by volume, 30 parts by volume, 35 parts by volume, 40 parts by volume, 45 parts by volume, 55 parts by volume, 60 parts by volume, or all ranges and subranges and point values therebetween.

For a formulation composition, the ethyl acetate content may be 5-20 parts by volume, 10-20 parts by volume, 15-20 parts by volume, 10-15 parts by volume, 5 parts by volume, 10 parts by volume, 15 parts by volume, 20 parts by volume, or all ranges and subranges and point values therebetween.

For a formulation composition, the ketone content can be 20-80 parts by volume, 20-70 parts by volume, 20-60 parts by volume, 20-50 parts by volume, 20-40 parts by volume, 20-30 parts by volume, 30-70 parts by volume, 40-60 parts by volume, 20 parts by volume, 30 parts by volume, 40 parts by volume, 50 parts by volume, 60 parts by volume, 70 parts by volume, 80 parts by volume, or all ranges and subranges and point values therebetween. The ketones may comprise or consist of acetone or butanone.

Without wishing to be bound by theory, in the present application, the combination of acetonitrile, ethyl acetate and ketones is used to contact the oil sludge and then the oil sludge is completely mixed with water in the oil-containing sludge, but inorganic sediments in the oil sludge are precipitated from the liquid phase, and substances such as polar humic acid are also precipitated from the liquid phase. Thus, the main components mixed with the formulation composition comprising acetonitrile, ethyl acetate, ketones are oil and water, forming a new oil-solvent-water system. The sediment can be removed by adopting methods of sedimentation or centrifugal separation, and the sediment can be used for constructing and laying oil fields after being treated for many times and the oil content is lower than 0.3 percent. Heating the separated oil-solvent-water system, volatilizing the solvent when the temperature reaches 80-95 ℃, and condensing to recover. The remaining oil-water can be recovered by oil field separation method. In addition, the separation effect can be further enhanced by adding a surfactant to a preparation composition containing acetonitrile, ethyl acetate, and ketones.

In the prior art, petroleum ether, gasoline, carbon tetrachloride and toluene are mainly used for recovering the oily sludge. However, petroleum ether, gasoline, carbon tetrachloride and toluene are insoluble in water, and although oil in oil sludge can be separated, two problems exist: due to the phenomena of water-in-oil and oil-in-water, oil and solvent are remained in the sediments (sludge), and the residual quantity is often over 3 weight percent, so that the requirement that the oil content of the sediments is lower than 0.3 weight percent cannot be met at present.

2. Method for treating oily sludge

The treatment method of the oily sludge comprises the following steps:

(4) Adding the solid-phase sediments into the preparation composition prepared in the step (1) again, and forming a liquid phase and a solid-phase sediments by adopting the solid-liquid separator again;

(7) Optionally, the oil-water mixture is separated to obtain separate oil and water.

As regards the formulation composition used in the treatment method, it may be any of the formulation compositions described in the first aspect of the present application. For example, the formulation composition may comprise or consist of acetonitrile, ethyl acetate, ketones. For ketones in the formulation composition, they may comprise, consist of, or consist of acetone or butanone. For example, the formulation composition may comprise: 1) Acetonitrile, ethyl acetate, acetone; 2) Acetonitrile, ethyl acetate, butanone. For another example, the formulation composition may be composed of: 1) Acetonitrile, ethyl acetate, acetone; 2) Acetonitrile, ethyl acetate, butanone.

For a formulation composition, the acetonitrile content may be 10-60 volume parts, 20-60 volume parts, 30-60 volume parts, 40-60 volume parts, 50-60 volume parts, 15-55 volume parts, 20-50 volume parts, 25-45 volume parts, 30-40 volume parts, 10 volume parts, 15 volume parts, 20 volume parts, 25 volume parts, 30 volume parts, 35 volume parts, 40 volume parts, 45 volume parts, 55 volume parts, 60 volume parts, or all ranges and subranges and point values therebetween.

For step (4) in the treatment method, the steps of 5-10, 6-9, 7-8, 5, 6, 7, 8, 9, 10, or all ranges and subranges and point values therebetween are repeated.

For step (2) of the treatment process, the oily sludge (on a dry weight basis) has a concentration in the oily sludge of 10-900g/L, 20-800g/L, 30-700g/L, 40-600g/L, 50-500g/L, 10g/L, 50g/L, 100g/L, 150g/L, 200g/L, 250g/L, 300g/L, 350g/L, 400g/L, 450g/L, 500g/L, 550g/L, 600g/L, 650g/L, 700g/L, 750g/L, 800g/L, 850g/L, 900g/L, or all ranges and subranges and points therebetween.

For step (5) in the treatment method, the prescribed value is 0.3 wt%, 0.2 wt%, 0.1 wt%, and all points in between.

For step (2) in the treatment method, the duration is more than 10 minutes, more than 20 minutes, more than 30 minutes, more than 40 minutes, more than 50 minutes, more than 60 minutes, and all points in between.

For step (6) in the treatment process, the temperature of the evaporator is 80-95 degrees Celsius, 85-90 degrees Celsius, 90-95 degrees Celsius, 85 degrees Celsius, 90 degrees Celsius, 95 degrees Celsius, or all ranges and subranges and point values therebetween. Low temperature evaporation is achieved by the formulation composition of the present application. The formulation composition of the present application is miscible with both water and oil, which enables oil extraction, resulting in a sludge with very low oil content. Without wishing to be bound by theory, the formulation compositions of the present application, and the components therein, both have boiling points below 90 degrees and do not form hydrogen bonds with water, which enables the present application to achieve separation using evaporation, and more specifically, low temperature evaporation (e.g., below 90 degrees, below 85 degrees).

For step (6) of the treatment method, the duration in the evaporator is 10-60 minutes, 10-50 minutes, 10-40 minutes, 10-30 minutes, 10-20 minutes, 20-50 minutes, 30-40 minutes, 10 minutes, 20 minutes, 30 minutes, 40 minutes, 50 minutes, 60 minutes, or all ranges and subranges and point values therebetween.

For step (7) of the process, any conventional water-oil separation process known in the art may be used to obtain separate oil and water.

3. Treatment equipment for oily sludge

Oily sludge's treatment facility, it includes agitating unit, mixing arrangement, solid-liquid separator, evaporation plant, recovery unit, wherein:

(3) Separating in a solid-liquid separator to obtain a liquid phase and a solid phase sediment;

As regards the formulation composition used in the treatment device, it may be any formulation composition described in the first aspect of the present application. For example, the formulation composition may comprise or consist of acetonitrile, ethyl acetate, ketones. For ketones in the formulation composition, they may comprise, consist of, or consist of acetone or butanone. For example, the formulation composition may comprise: 1) Acetonitrile, ethyl acetate, acetone; 2) Acetonitrile, ethyl acetate, butanone. For another example, the formulation composition may be composed of: 1) Acetonitrile, ethyl acetate, acetone; 2) Acetonitrile, ethyl acetate, butanone.

The solid-liquid separator of the treatment equipment comprises a gravity settling tank, a plate-frame dehydrator, a centrifugal machine, a water conservancy cyclone separator and a standing tank.

For the evaporation means of the treatment apparatus, it comprises heating and condensing means.

For the evaporator of the processing apparatus, the temperature is 80-95 degrees celsius, 85-90 degrees celsius, 90-95 degrees celsius, 85 degrees celsius, 90 degrees celsius, 95 degrees celsius, or all ranges and subranges and point values therebetween.

The duration in the evaporator of the treatment apparatus is 10-60 minutes, 10-50 minutes, 10-40 minutes, 10-30 minutes, 10-20 minutes, 20-50 minutes, 30-40 minutes, 10 minutes, 20 minutes, 30 minutes, 40 minutes, 50 minutes, 60 minutes, or all ranges and subranges and point values therebetween.

Examples

The invention will be better understood from the following examples. However, those skilled in the art will readily appreciate that the specific material ratios, process conditions and results thereof described in the examples are illustrative only and should not be taken as limiting the invention as detailed in the claims.

Acetonitrile, ethyl acetate, acetone and butanone used in the examples are commercially available products.

Preparation examples

The preparation composition is prepared by mixing the preparation components in a container according to a certain proportion by adopting a conventional method.

The oil-containing sludge with oil content of 40% is obtained from oil tank bottom sludge.

Recovery examples

The oily sludge is recovered by the following process:

1) Adding oily sludge into the prepared preparation composition, wherein each volume of oily sludge is 100 parts by volume of the preparation composition;

2) Thoroughly mixing (about 20 minutes) in a cylindrical tank equipped with a paddle stirrer to obtain an oily sludge, and determining the content of the oily sludge in the oily sludge;

3) Liquid and solid phase sludge were separated by gravity settling tank and the oil content of the solid phase sludge fraction was determined after each separation. If the oil content is above 0.3 wt%, the procedure is repeated until the oil content is below 0.3 wt%;

4) The liquid phase is added into a multi-effect evaporator, heated at 90 ℃ and then condensed to remove the formulation composition.

The process conditions and treatment effects involved in the examples are listed in table 1 below.

TABLE 1

Comparative example

The oil in the oily sludge is recovered by adopting petroleum ether, gasoline, carbon tetrachloride and toluene which are commonly used in the prior art. The same preparation and recovery procedures were used as in the previous examples. Petroleum ether, gasoline, carbon tetrachloride and toluene are 100 parts by volume respectively.

The process conditions and treatment effects related to the comparative examples are shown in table 2 below.

TABLE 2

Comparison it can be seen that with the formulation compositions of the present application, for examples 1, 2, 5, 6, an oil content of less than 0.21% can be achieved after 6 solid-liquid separations. For examples 3, 4, an oil content of less than 0.26% could be achieved after 9 solid-liquid separations. In contrast, in comparative examples 7 to 10, the final oil content was still high after 6 solid-liquid separations (1.8% in comparative example 9 and as high as 6.2% in comparative example 10).

FIGS. 2 and 3 are graphs showing the comparison between the examples of the present application and the comparative examples. In FIG. 2, the effect of treating the oily sludge of examples 1 to 6 of the present application is summarized. Referring to fig. 2, it can be seen that the oil content of the above examples after final treatment is only about 0.26% at the maximum. In addition, the effects of treating oily sludge in examples 1 to 6 and comparative examples 7 to 10 of the present application are compared in FIG. 3. Referring to fig. 3, it can be seen that in the comparative example, the oil content after final treatment is still much higher than that of the present application.

Although the foregoing invention has been described in some detail for purposes of clarity and understanding, it will be appreciated by those skilled in the art from a reading of this specification that various modifications and changes can be made thereto without departing from the spirit and scope of the invention, which is to be encompassed by the appended claims and their equivalents.

The present application relates to any combination of the following embodiments: 1. a formulation composition comprising acetonitrile, ethyl acetate, ketones.

2. The formulation composition of embodiment 1, wherein the acetonitrile is 10 to 60 parts by volume, the ethyl acetate is 5 to 20 parts by volume, and the ketones are 20 to 80 parts by volume.

A formulation according to embodiment 2, wherein the acetonitrile is present in an amount of 40 to 60 parts by volume, the ethyl acetate is present in an amount of 10 to 20 parts by volume, and the ketones are present in an amount of 20 to 40 parts by volume.

4. A formulation according to embodiment 3, wherein the acetonitrile is present in 60 parts by volume, the ethyl acetate is present in 20 parts by volume and the ketones are present in 20-30 parts by volume.

5. A formulation composition according to any one of embodiments 1 to 4, wherein the ketone comprises acetone or butanone.

6. A method for treating oily sludge, which comprises the following steps:

(1) Providing a formulation composition according to any one of embodiments 1 to 5;

(5) Repeating the step (4) until the oil content of the obtained solid-phase sediment is lower than a specified value;

(6) Collecting the liquid phase obtained in the step (4) and/or (5), adding the liquid phase into an evaporator for evaporation treatment, and separating the preparation composition from the liquid phase to form a preparation composition and an oil-water mixture;

7. The method according to embodiment 6, wherein the concentration of the oily sludge in the oily turbidity solution in the step (2) is 50 to 500g/L in terms of dry weight.

8. The method of embodiment 6, wherein step (4) is repeated 5-10 times.

9. The method of embodiment 6, wherein the formulation composition formed in step (6) is recovered and reused in step (2).

10. The method of embodiment 6, wherein step (2) lasts more than 20 minutes.

11. A method for treating oily sludge, which comprises the following steps:

12. The method of embodiment 11, wherein step (4) is repeated 5-10 times.

13. The method of embodiment 12, wherein step (4) is repeated 6-9 times.

14. The method according to embodiment 11, wherein the concentration of the oily sludge in the step (2) is 50 to 500g/L in terms of dry weight.

15. The method of embodiment 11, wherein the defined value is 0.3 wt% or 0.1 wt%.

16. The method of embodiment 11, wherein step (2) lasts for more than 20 minutes.

17. The method of embodiment 11, wherein the formulation composition formed in step (6) is recycled for reuse in step (2).

18. The utility model provides an oily sludge's treatment facility, its includes agitating unit, mixing arrangement, solid-liquid separator, evaporation plant, recovery unit, wherein:

(4) Evaporating the liquid phase in an evaporation device to separate the preparation composition and oil-water mixture from the liquid phase;

(5) In the recovery device, the oil-water mixture is separated to obtain separated oil and water.

19. The apparatus of embodiment 18, wherein the solid-liquid separator is a gravity settling tank.

20. The apparatus for treating oily sludge according to embodiment 18, wherein the temperature of the evaporator is 80 to 95 ℃.

Claims

1. The preparation composition for recovering the oil-containing sludge is composed of acetonitrile, ethyl acetate and ketones, and is characterized in that the acetonitrile accounts for 10-60 volume parts, the ethyl acetate accounts for 5-20 volume parts, and the ketones account for 20-80 volume parts.

2. The formulation composition of claim 1, wherein acetonitrile is 40-60 parts by volume, ethyl acetate is 10-20 parts by volume, and ketones are 20-40 parts by volume.

3. The formulation composition of claim 2, wherein acetonitrile is 60 parts by volume, ethyl acetate is 20 parts by volume, and ketones are 20-30 parts by volume.

4. A formulation composition according to any one of claims 1 to 3, wherein the ketone comprises acetone or butanone.

5. A method for treating oily sludge, which comprises the following steps:

(1) Providing a formulation composition according to any one of claims 1 to 4;

(6) Collecting the liquid phase obtained in step (4) and/or (5), adding the liquid phase into an evaporator for evaporation treatment, and separating the preparation composition from the liquid phase to form the preparation composition and an oil-water mixture.

6. The method according to claim 5, wherein the concentration of the oily sludge in the step (2) is 50 to 500g/L in terms of dry weight.

7. The method of claim 5, wherein step (4) is repeated 5-10 times.

8. The method of claim 5, wherein the formulation composition formed in step (6) is recycled for reuse in step (2).

9. The method of claim 5, wherein step (2) lasts for more than 20 minutes.

10. The method of claim 5, further comprising the step of (7) separating the oil-water mixture to obtain separated oil and water.