A method of solvent extraction of oil sludge / oil sand assisted by a particle dispersant

Abstract

The application provides a granular dispersant assisted solvent extraction method for oil sludge / oil sand, and belongs to the technical field of chemical separation.The application provides a granular dispersant assisted solvent extraction method for oil sludge / oil sand, which comprises the following steps: mixing a solution of a granular dispersant with oil sludge / oil sand, performing solvent extraction, and separating to obtain solid phase particles and liquid phase; the granular dispersant comprises fatty alcohol polyoxyethylene ether carboxylic acid, fatty alcohol polyoxypropylene polyoxyethylene ether carboxylic acid or dodecyl benzene sulfonic acid.In the application, the oil sludge / oil sand is a mixed system of crude oil, water and mineral particles, wherein water can cause mineral particle agglomeration, and mineral particle agglomeration can bind asphaltene aggregates in the crude oil; by adding the granular dispersant, the repulsive force between the mineral particles is increased, so that the mineral particles are dispersed, thereby the bound asphaltene aggregates can be released, and the residual oil rate of the solid phase particles is reduced.

Description

Technical Field

[0001] This invention belongs to the field of chemical separation technology, specifically relating to a solvent extraction method for oil sludge / oil sand assisted by a particulate dispersant. Background Technology

[0002] With the rapid development of the global economy and the continuous increase in oil demand, a large amount of crude oil sludge is generated during the conventional crude oil extraction, transportation, storage and refining process. If these pollutants are not properly disposed of, they will threaten the ecological environment and human health. The resource utilization and harmless treatment of crude oil sludge is one of the problems facing the oil industry. In addition, the supply shortage of conventional oil has led people to turn their attention to unconventional oil resources. Among them, oil sands are rich in crude oil resources, accounting for 30% of the world's oil reserves, and are receiving increasing attention from the world as an important reserve resource.

[0003] Solvent extraction is a common method for recovering crude oil from oil sludge / oil sands. Based on the principle of "like dissolves like," solvents with solubility parameters close to those of crude oil are selected or formulated for extraction. However, asphaltenes are dispersed in the solvent as aggregates, and solubility parameters are not the only factor affecting solvent extraction. Oil sludge / oil sands contain a small amount of water. During solvent extraction, water provides capillary attraction, promoting the aggregation of mineral particles and binding asphaltenes. This makes it difficult to separate the asphaltenes aggregates, resulting in a high residual oil content.

[0004] Patent CN113881449 B discloses a low-temperature pyrolysis treatment method for oily waste. Before pyrolysis, the oily waste is treated with a dodecylbenzenesulfonic acid solution in n-heptane, a white oil solution, and a kerosene solution to remove asphalt. Asphalt is severely aggregated in unsuitable solvents such as n-heptane, white oil, and kerosene. Dodecylbenzenesulfonic acid, as a good asphalt dispersant, can effectively promote asphalt dispersion. After deasphalting, thermal desorption at 200–400°C reduces the residual oil content of solid particles to below 1 wt%. Patent CN113754213 A discloses the application of a pretreatment solution in heavy oil sludge. A pretreatment solution is prepared by mixing asphalt dispersants dodecylbenzenesulfonic acid, p-dodecylphenol, and N,N-di(hydroxyethyl)cocoamide with non-polar solvents such as n-heptane, n-dodecane, white oil, and gas-to-oil. This pretreatment solution is mixed with the sludge to assist in asphalt removal, followed by chemical thermal cleaning at 20–60°C, which reduces the residual oil content to below 1 wt%. The solvents extracted in the above patents are straight-chain alkanes such as n-heptane and white oil. The solubility parameters of these alkane solvents are quite different from those of asphaltenes. Asphaltenes tend to aggregate severely in these alkane solvents. The purpose of using dodecylbenzene sulfonic acid as an asphaltenes dispersant is to disperse asphaltenes, without considering the problem of mineral particle dispersion (if asphaltenes are not dispersed, even if mineral particles are dispersed, it is impossible to separate the solid particles from the asphaltenes in the end). Furthermore, after deasphalting, further processing is required to reduce the residual oil content to below 1 wt%. Summary of the Invention

[0005] In view of this, the object of the present invention is to provide a solvent extraction method for oil sludge / oil sands assisted by a particulate dispersant. The method provided by the present invention addresses the problem of mineral particle agglomeration during solvent extraction, and can separate the bound asphaltene aggregates from the mineral particles, thereby reducing the residual oil content in the solid phase particles.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] This invention provides a solvent extraction method for oil sludge / oil sands assisted by a particulate dispersant, comprising the following steps:

[0008] The solution containing the particulate dispersant was mixed with oil sludge / oil sand, and solvent extraction was performed to separate the solid particles and the oil-carrying liquid phase.

[0009] The particulate dispersant includes fatty alcohol polyoxyethylene ether carboxylic acid, fatty alcohol polyoxypropylene polyoxyethylene ether carboxylic acid, or dodecylbenzene sulfonic acid.

[0010] The solvent used in the solution containing the particulate dispersant includes one or more of cycloalkanes and toluene.

[0011] Preferably, the separation includes gravity sedimentation or centrifugation; the gravity sedimentation time is 0.5 to 60 minutes; the centrifugation speed is 500 to 3000 r / min, and the time is 3 to 30 minutes.

[0012] Preferably, the oil sludge / oil sand has an oil content of 5-30 wt%, a water content of 4-20 wt%, and a solid content of 57-92 wt%.

[0013] Preferably, the mass ratio of the oil sludge / oil sand to the solution containing the particulate dispersant is 1:(0.5-3).

[0014] Preferably, the cycloalkane includes cyclohexane and / or cyclopentane.

[0015] Preferably, the mass of the particulate dispersant is less than 2.5% of the mass of the solution in which the particulate dispersant is dissolved.

[0016] Preferably, the solvent extraction is carried out under stirring conditions; the stirring speed is 300-2000 r / min, and the time is 10-120 min.

[0017] Preferably, after separating the solid particles, the process further includes washing and drying the solid particles sequentially; the drying temperature is 70–110°C.

[0018] Preferably, after drying, the process further includes low-temperature thermal desorption of the dried solid particles to remove residual solvent; the temperature of the low-temperature thermal desorption is 250-350°C, and the time is 30-60 minutes.

[0019] Preferably, after separating the oil-carrying liquid phase, the process further includes rotary evaporation of the oil-carrying liquid phase to obtain crude oil and solvent, respectively.

[0020] This invention provides a solvent extraction method for oil sludge / oil sands assisted by a particulate dispersant, comprising the following steps: mixing a solution containing a particulate dispersant with the oil sludge / oil sands, performing solvent extraction, and separating solid particles and an oil-bearing liquid phase; the particulate dispersant includes fatty alcohol polyoxyethylene ether carboxylic acid, fatty alcohol polyoxypropylene polyoxyethylene ether carboxylic acid, or dodecylbenzene sulfonic acid; the solvent used in the solution containing the particulate dispersant includes one or more of cycloalkanes and toluene. In this invention, the oil sludge / oil sands is a mixture of crude oil, water, and mineral particles, wherein water causes mineral particles to agglomerate, and the agglomeration of mineral particles binds asphaltenes aggregates in the crude oil. This invention uses one or more of cycloalkanes and toluene as solvents. The solubility parameters of cycloalkanes are similar to those of asphaltenes, and asphaltenes agglomerate less in cycloalkanes, resulting in smaller aggregate sizes. Therefore, the problem of dispersing asphaltenes is not considered, further highlighting the problem of mineral particle agglomeration. This invention increases the repulsive force between mineral particles by adding a particulate dispersant, thereby dispersing the mineral particles, releasing the bound asphaltenes aggregates, and reducing the residual oil content of the solid particles. This invention eliminates the need for low-temperature thermal desorption, reducing the residual oil content of the solid particles to below 1% after drying. After removing residual solvent through low-temperature thermal desorption at 250–350°C, the residual oil content of the solid particles can reach below 0.1%, meeting higher environmental emission requirements; it can recover up to nearly 100% of the crude oil, resulting in high-quality crude oil.

[0021] Furthermore, by controlling the settling time under gravity and the centrifugal rotation speed, the present invention can rapidly separate solid particles and asphaltene aggregate dispersion systems.

[0022] Furthermore, the particulate dispersant and organic solvent of this invention have low toxicity, and the organic solvent has a low boiling point, making it easy to recover. This invention has the advantages of being simple, efficient, energy-saving, and low in toxicity, overturning the traditional "like dissolves like" theory and achieving the goal of "no sand in oil, no oil in sand". Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a flowchart of the solvent extraction process for oil sludge in this invention;

[0025] Figure 2 This is a flowchart of the solvent extraction process for oil sands according to the present invention. Detailed Implementation

[0026] This invention provides a solvent extraction method for oil sludge / oil sands assisted by a particulate dispersant, comprising the following steps:

[0027] The solution containing the particulate dispersant is mixed with oil sludge / oil sand, and solvent extraction is performed to separate the solid particles and the oil-carrying liquid phase.

[0028] In this invention, the particulate dispersant comprises fatty alcohol polyoxyethylene ether carboxylic acid, fatty alcohol polyoxypropylene polyoxyethylene ether carboxylic acid, or dodecylbenzene sulfonic acid; the fatty alcohol polyoxyethylene ether carboxylic acid preferably comprises fatty alcohol polyoxyethylene ether carboxylic acid C. 12 E9Ac, fatty alcohol polyoxyethylene ether carboxylic acid C 18 E9Ac, fatty alcohol polyoxyethylene ether carboxylic acid C 12 E 2.5 Ac or fatty alcohol polyoxyethylene ether carboxylic acid C 18 E2Ac; the fatty alcohol polyoxypropylene polyoxyethylene ether carboxylic acid preferably includes fatty alcohol polyoxypropylene polyoxyethylene ether carboxylic acid C. 13 P3E 5.5 Ac. In this invention, the solvent used in the solution containing the particulate dispersant includes one or more of cycloalkanes and toluene; the cycloalkanes preferably include cyclohexane and / or cyclopentane. In this invention, the mass of the particulate dispersant is preferably less than 2.5% of the mass of the solution containing the particulate dispersant, more preferably 0.5% to 2.0%, and more preferably 1% to 1.75%.

[0029] In this invention, the oil content of the oil sludge / oil sand is preferably 5-30 wt%, more preferably 8-25 wt%, and even more preferably 12-20 wt%; the water content of the oil sludge / oil sand is preferably 4-20 wt%, more preferably 6-18 wt%, and even more preferably 8-15 wt%; the solid content of the oil sludge / oil sand is preferably 57-92 wt%, more preferably 60-88 wt%, and even more preferably 65-75 wt%. In this invention, the mass ratio of the oil sludge / oil sand to the solution containing the particulate dispersant is preferably 1:(0.5-3), more preferably 1:(0.8-2.5), and even more preferably 1:(1-2.2).

[0030] In this invention, the solvent extraction is preferably carried out under stirring conditions; the stirring speed is preferably 300-2000 r / min, more preferably 450-1800 r / min, and even more preferably 600-1500 r / min; the stirring time is preferably 10-120 min, more preferably 20-100 min, and even more preferably 40-180 min.

[0031] In this invention, the separation preferably includes gravity sedimentation or centrifugation; the gravity sedimentation time is preferably 0.5–60 min, more preferably 5–50 min, and even more preferably 10–40 min; the centrifugation speed is preferably 500–3000 r / min, more preferably 650–2500 r / min, and even more preferably 800–2000 r / min; the centrifugation time is preferably 3–30 min, more preferably 8–25 min, and even more preferably 10–20 min. This invention does not have special requirements for the gravity sedimentation; in the embodiments of this invention, it is specifically static settling. By controlling the sedimentation time under gravity and the centrifugation speed, this invention can rapidly separate solid particles and asphaltene aggregate dispersion systems.

[0032] In this invention, after separating the solid particles, it is preferable to further include washing and drying the solid particles sequentially. In a specific embodiment of this invention, the washing solvent is a solvent for dissolving the corresponding particle dispersant; in this invention, the drying temperature is preferably 70-110°C, more preferably 75-105°C, and even more preferably 80-100°C. This invention does not have a particular requirement for the drying time, as long as the solid particles are dried to a constant weight. In this invention, after drying, it is preferable to further include low-temperature thermal desorption of the dried solid particles to remove residual solvent; the low-temperature thermal desorption temperature is preferably 250-350°C, more preferably 270-330°C, and even more preferably 285-320°C; the low-temperature thermal desorption time is preferably 30-60 min, more preferably 35-55 min, and even more preferably 40-50 min. In this invention, it is preferable to place the dried solid particles in a muffle furnace for low-temperature thermal desorption and heat them in a nitrogen atmosphere, which can further evaporate the solvent remaining on the solid particles, thereby reducing the residual oil content and meeting higher environmental emission requirements.

[0033] In this invention, after separating the oil-carrying liquid phase, it is preferable to further perform rotary evaporation on the oil-carrying liquid phase to obtain crude oil and solvent respectively.

[0034] Figure 1 This is a flowchart illustrating the solvent extraction process for the sludge in this invention. Figure 1As shown, the present invention mixes a solution containing a particulate dispersant with oil sludge, performs solvent extraction, and separates solid and liquid phases by controlling the settling time under gravity or the centrifugal speed to obtain solid particles and an oil-carrying liquid phase. After separation, the solid particles are dried at different temperatures or subjected to low-temperature thermal desorption to remove residual solvent. After separation, the oil-carrying liquid phase is used to recover crude oil by rotary evaporation and reuse the solvent.

[0035] To further illustrate the present invention, the solvent extraction method for oil sludge / oil sand assisted by the particulate dispersant provided by the present invention will be described in detail below with reference to the accompanying drawings and embodiments, but these should not be construed as limiting the scope of protection of the present invention.

[0036] Example 1

[0037] Taking a certain type of oily sludge from Shengli (oil content 28wt%, water content 15wt%, solid content 57wt%, asphaltene content 5.91wt%) as an example. The fatty alcohol polyoxyethylene ether carboxylic acid C... 12 E9Ac is dissolved in cyclohexane to prepare 0.5% C 12 E9Ac-cyclohexane solution (0.5% is C 12 The mass of E9Ac accounts for C 12 (Percentage of total mass of E9Ac-cyclohexane solution), 2g of oil sludge was mixed with 2g of cyclohexane solution and stirred at 500r / min for 30min. The mixture was then allowed to stand under gravity for 10min to separate the lower solid particles. The solid particles were washed with 1g of cyclohexane and placed in an 80℃ oven. The residual oil content of the dried solid particles is shown in Table 1. To meet higher environmental emission standards, the solid particles were subjected to low-temperature thermal desorption at 350℃ to remove residual solvent. The residual oil content of the solid particles after thermal desorption is shown in Table 1. The upper oil-carrying liquid phase was recovered by rotary evaporation and the cyclohexane was reused.

[0038] Comparative Example 1

[0039] The steps are the same as in Example 1, except that fatty alcohol polyoxyethylene ether carboxylic acid C is not added. 12 E9Ac, preparing 0% C 12 E9Ac-cyclohexane solution. The residual oil content of solid particles after drying and thermal desorption is shown in Table 1.

[0040] Table 1. Residual oil content (%) of solid particles after treatment

[0041]

[0042] Example 1 and Comparative Example 1 show that, for the system without a particulate dispersant, the amount of residual oil in the solid particles after drying is relatively high. This is because the mineral particles agglomerate, causing the asphaltenes to be bound and unable to be separated during solvent extraction, resulting in a higher amount of residual oil in the solid particles after drying. However, the system with the added particulate dispersant, fatty alcohol polyoxyethylene ether carboxylic acid C…12 After E9Ac, the residual oil content of solid particles decreased significantly, which is due to C 12 E9Ac disperses mineral particles, releasing asphaltenes and reducing the amount of residual oil in solid particles. In this example, the crude oil recovery rate is close to 100%, and no water or solid particles were detected in the recovered crude oil, indicating high crude oil quality; cyclohexane can be recycled.

[0043] Examples 2-5

[0044] Taking a certain type of oily sludge from the Environmental Safety Institute (oil content 6.9 wt%, water content 12.6 wt%, solid content 80.5 wt%, asphaltene content 0.51 wt%) as an example. The fatty alcohol polyoxyethylene ether carboxylic acid C... 12 E9Ac was dissolved in cyclohexane to prepare 0.10%, 0.25%, 0.50%, and 0.75% C64 solutions. 12 E9Ac-cyclohexane solutions (0.10%, 0.25%, 0.50%, and 0.75% for C) 12 The mass of E9Ac accounts for C 12 (Percentage of total mass of E9Ac-cyclohexane solution), 2g of oil sludge was mixed with 2g of cyclohexane solution of different concentrations, stirred at 500r / min for 30min, and the mixture was allowed to stand under gravity for 5min to separate the lower solid particles. The solid particles were washed with 1g of cyclohexane and placed in a 70℃ oven. The residual oil content of the solid particles after drying is shown in Table 2. In order to meet higher environmental emission standards, the solid particles were subjected to low-temperature thermal desorption at 300℃ to remove residual solvent. The residual oil content of the solid particles after thermal desorption is shown in Table 2. The upper oil-carrying liquid phase was recovered by rotary evaporation and the cyclohexane was reused.

[0045] Comparative Example 2

[0046] The steps are the same as in Example 2, except that fatty alcohol polyoxyethylene ether carboxylic acid C is not added. 12 E9Ac, preparing 0% C 12 E9Ac-cyclohexane solution. The residual oil content of solid particles after drying and thermal desorption is shown in Table 2.

[0047] Table 2. Residual oil content (%) of solid particles after treatment

[0048]

[0049] The patterns of Examples 2-5 and Comparative Example 2 are consistent with those of Examples 1 and Comparative Example 1. The residual oil content of solid particles after drying is less than 0.3%, and the residual oil content of solid particles after thermal desorption is less than 0.1%. The crude oil recovery rate is above 95%, and cyclohexane can be recycled.

[0050] Examples 6-13

[0051] Take simulated oil sludge (25wt% oil content, 20wt% water content, 55wt% solid content, and 2.5wt% asphalt content) as an example. DBSA (dodecylbenzenesulfonic acid) was dissolved in toluene to prepare DBSA-toluene solutions of 0.10%, 0.25%, 0.50%, 0.75%, 1.00%, 1.25%, 1.50%, and 2.00% (0.10%, 0.25%, 0.50%, 0.75%, 1.00%, 1.25%, 1.50%, and 2.00% are the percentages of DBSA by mass relative to the total mass of the DBSA-toluene solution). 1g of oil sludge was mixed with 1g of toluene solutions of different concentrations and stirred at 500r / min for 30min. The mixture was then centrifuged at 1000r / min for 10min to separate the lower solid phase particles. The solid particles were washed with 0.5g of toluene and then placed in a 90℃ oven. The residual oil content of the dried solid particles is shown in Table 3. The upper oil-carrying liquid phase was recovered by rotary evaporation, and the toluene was reused.

[0052] In this embodiment, DBSA is used as a particulate dispersant. To eliminate the influence of DBSA on the dispersion of asphaltene, toluene, a good solvent for asphaltene, is used as the solvent.

[0053] Comparative Example 3

[0054] The procedure was the same as in Example 6, except that dodecylbenzenesulfonic acid (DBSA) was not added to prepare a 0% DBSA-toluene solution. The residual oil content of the solid particles after drying is shown in Table 3.

[0055] Table 3 Residual oil content of solid particles after treatment

[0056] serial number DBSA concentration (%) Residual oil content in solid particles after drying (%) Comparative Example 3 0 3.29 Example 6 0.10 3.75 Example 7 0.25 3.00 Example 8 0.50 1.74 Example 9 0.75 0.27 Example 10 1.00 0.43 Example 11 1.25 0.23 Example 12 1.50 0.11 Example 13 2.00 0.14

[0057] The results of Examples 6-13 and Comparative Example 3 show that for oil sludge with agglomerated mineral particles, even when toluene is used as a solvent, the residual oil content of the solid particles after extraction is as high as 3.29%. After adding the particle dispersant dodecylbenzenesulfonic acid (DBSA), the residual oil content of the solid particles is significantly reduced. Moreover, as the amount of particle dispersant increases, the residual oil content of the solid particles shows a decreasing trend and eventually tends to stabilize, with the lowest residual oil content reaching 0.11%.

[0058] Examples 14-21

[0059] Taking simulated oil sludge (oil content 25wt%, water content 20wt%, solid content 55wt%, asphaltene content 2.5wt%) as an example. Fatty alcohol polyoxyethylene ether carboxylic acid C... 12 E9Ac is dissolved in toluene to prepare 0.10%, 0.25%, 0.50%, 0.75%, 1.00%, 1.25%, 1.50%, and 2.00% C... 12E9Ac-toluene solution (0.10%, 0.25%, 0.50%, 0.75%, 1.00%, 1.25%, 1.50%, and 2.00% for C) 12 The mass of E9Ac accounts for C 12 (Percentage of total mass of E9Ac-toluene solution), take 1g of oil sludge and mix it with 1g of toluene solution of different concentrations, stir at 500r / min for 30min, place the mixture in a centrifuge tube and centrifuge at 1000r / min for 10min to separate the lower solid phase particles, wash the solid phase particles with 0.5g of toluene and place them in a 90℃ oven. The residual oil content of the solid phase particles after drying is shown in Table 4; the upper oil-carrying liquid phase is recovered by rotary evaporation and the toluene is reused.

[0060] Comparative Example 4

[0061] The steps are the same as in Example 14, except that fatty alcohol polyoxyethylene ether carboxylic acid C is not added. 12 E9Ac, preparing 0% C 12 E9Ac-toluene solution. The residual oil content of the solid particles after drying is shown in Table 4.

[0062] Table 4 Residual oil content of solid particles after treatment

[0063] serial number <![CDATA[C 12 E9Ac concentration (%) Residual oil content of dried particles (%) Comparative Example 4 0 3.29 Example 14 0.10 1.40 Example 15 0.25 1.13 Example 16 0.50 0.91 Example 17 0.75 0.32 Example 18 1.00 0.30 Example 19 1.25 0.27 Example 20 1.50 0.23 Example 21 2.00 0.27

[0064] The patterns observed in Examples 14-21 and Comparative Example 4 are consistent with those in Examples 6 and Comparative Example 3, with the residual oil content of solid particles being reduced to as low as 0.23%.

[0065] Examples 22-28

[0066] Taking simulated oil sludge (oil content 25wt%, water content 20wt%, solid content 55wt%, asphaltene content 2.5wt%) as an example. Fatty alcohol polyoxyethylene ether carboxylic acid C... 12 E9Ac was dissolved in cyclohexane to prepare 0.25%, 0.5%, 0.75%, 1%, 1.25%, 1.5%, and 2% C64 solutions. 12 E9Ac-cyclohexane solution (0.25%, 0.5%, 0.75%, 1%, 1.25%, 1.5% and 2% for C) 12 The mass of E9Ac accounts for C 12 (Percentage of total mass of E9Ac-cyclohexane solution), take 1g of oil sludge and mix it with 1g of cyclohexane solution of different concentrations, stir at 500r / min for 30min, place the mixture in a centrifuge tube and centrifuge at 1000r / min for 10min to separate the lower solid phase particles, wash the solid phase particles with 0.5g of cyclohexane and place them in a 90℃ oven. The residual oil content of the solid phase particles after drying is shown in Table 5; the upper oil-carrying liquid phase is recovered by rotary evaporation and the cyclohexane is reused.

[0067] Comparative Example 5

[0068] The steps are the same as in Example 22, except that fatty alcohol polyoxyethylene ether carboxylic acid C is not added. 12 E9Ac, preparing 0% C 12 E9Ac-cyclohexane solution. The residual oil content of the solid particles after drying is shown in Table 4.

[0069] Table 5 Residual oil content of solid particles after treatment

[0070] serial number <![CDATA[C 12 E9Ac concentration (%) Residual oil content in solid particles after drying (%) Comparative Example 5 0 3.12 Example 22 0.25 1.55 Example 23 0.50 1.64 Example 24 0.75 1.25 Example 25 1.00 0.98 Example 26 1.25 0.79 Example 27 1.50 0.56 Example 28 2.00 0.62

[0071] The patterns observed in Examples 22-28 and Comparative Example 5 are consistent with those in Examples 14-21 and Comparative Example 4, as well as Examples 6-13 and Comparative Example 3, with the residual oil content of solid particles being reduced to as low as 0.56%.

[0072] Examples 29-32

[0073] Taking simulated oil sludge (oil content 25wt%, water content 20wt%, solid content 55wt%, asphaltene content 2.5wt%) as an example. Fatty alcohol polyoxyethylene ether carboxylic acid C... 12 E9Ac is dissolved in cyclohexane to prepare 1% C 12 E9Ac-cyclohexane solution (1% is C) 12 The mass of E9Ac accounts for C 12 (Percentage of total mass of E9Ac-cyclohexane solution), take 1g of oil sludge and mix it with 1g of cyclohexane solution, stir at 500r / min for 30min, place the mixture in a centrifuge tube and centrifuge at 500, 1000, 2000 and 3000r / min for 10min to separate the lower solid phase particles, wash the solid phase particles with 0.5g of cyclohexane and place them in a 90℃ oven. The residual oil content of the solid phase particles after drying is shown in Table 6; the upper oil-carrying liquid phase is recovered by rotary evaporation and the cyclohexane is reused.

[0074] Table 6 Residual oil content of solid particles after treatment

[0075] serial number Centrifugation speed (r / min) Residual oil content of solid particles after drying (%) Example 29 500 2.21 Example 30 1000 0.79 Example 31 2000 1.78 Example 32 3000 1.90

[0076] Examples 29-32 investigated the effect of centrifugation speed on the residual oil content of solid particles. At low centrifugation speed (500 r / min), fine particles and asphaltene aggregates could not be separated, resulting in a high residual oil content in solid particles. At higher centrifugation speeds (2000-3000 r / min), asphaltene aggregates would settle and mix with solid particles under centrifugal force, leading to an increase in the residual oil content of solid particles.

[0077] Example 33

[0078] Taking Qinghai oil sludge (oil content 20wt%, water content 15wt%, solid content 65wt%, asphaltene content 2.5wt%) as an example. Fatty alcohol polyoxyethylene ether carboxylic acid C... 18 E9Ac dissolves in cyclopentane to prepare 2.5% C 18 E9Ac-cyclopentane solution (2.5% of C 18 The mass of E9Ac accounts for C 18 (Percentage of total mass of E9Ac-cyclopentane solution), take 1g of oil sludge and mix it with 1g of cyclopentane solution, stir at 500r / min for 30min, place the mixture in a centrifuge tube and centrifuge at 1000r / min for 10min to separate the lower solid phase particles, wash the solid phase particles with 1g of cyclopentane and place them in an 80℃ oven to dry. After drying, the residual oil content of the solid phase particles is 0.27%; the upper oil-carrying liquid phase is recovered by rotary evaporation and the cyclopentane is reused.

[0079] Example 34

[0080] Taking Qinghai oil sludge (oil content 20wt%, water content 15wt%, solid content 65wt%, asphaltene content 2.5wt%) as an example. Fatty alcohol polyoxyethylene ether carboxylic acid C... 12 E 2.5 Ac is dissolved in cyclopentane to prepare 2.5% C 12 E 2.5 Ac-cyclopentane solution (2.5% of C) 12 E 2.5 The mass of Ac accounts for C 12 E 2.5 (Percentage of total mass of Ac-cyclopentane solution), take 1g of oil sludge and mix it with 1g of cyclopentane solution, stir at 500r / min for 30min, place the mixture in a centrifuge tube and centrifuge at 1000r / min for 10min to separate the lower solid phase particles, wash the solid phase particles with 1g of cyclopentane and place them in an 80℃ oven to dry. After drying, the residual oil content of the solid phase particles is 0.46%; the upper oil-carrying liquid phase is recovered by rotary evaporation and the cyclopentane is reused.

[0081] Example 35

[0082] Taking Qinghai oil sludge (oil content 20wt%, water content 15wt%, solid content 65wt%, asphaltene content 2.5wt%) as an example. Fatty alcohol polyoxyethylene ether carboxylic acid C... 18 E2Ac is dissolved in cyclopentane to prepare 2.5% C 18 E2Ac-cyclopentane solution (2.5% is C 18 The mass of E2Ac accounts for a significant portion of C. 18(Percentage of total mass of E2Ac-cyclopentane solution), take 1g of oil sludge and mix it with 1g of cyclopentane solution, stir at 500r / min for 30min, place the mixture in a centrifuge tube and centrifuge at 1000r / min for 10min to separate the lower solid phase particles, wash the solid phase particles with 1g of cyclopentane and place them in an 80℃ oven to dry. After drying, the residual oil content of the solid phase particles is 0.45%; the upper oil-carrying liquid phase is recovered by rotary evaporation and the cyclopentane is reused.

[0083] Example 36

[0084] Taking simulated oil sludge (oil content 25wt%, water content 20wt%, solid content 65wt%, asphaltene content 2.5wt%) as an example. Fatty alcohol polyoxypropylene polyoxyethylene ether carboxylic acid C... 13 P3E 5.5 Ac is dissolved in cyclopentane to prepare 2.5% C 13 P3E 5.5 Ac-cyclopentane solution (2.5% of C) 13 P3E 5.5 The mass of Ac accounts for C 13 P3E 5.5 (Percentage of total mass of Ac-cyclopentane solution) Take 1g of crude oil sludge and mix it with 1g of cyclopentane solution. Stir at 500r / min for 30min. Place the mixture in a centrifuge tube and centrifuge at 1000r / min for 10min to separate the lower solid phase particles. Wash the solid phase particles with 1g of cyclopentane and place them in an 80℃ oven. After drying, the residual oil content of the solid phase particles is 0.76%. The upper oil-carrying liquid phase is evaporated to recover crude oil and reuse cyclopentane.

[0085] Examples 37-40

[0086] Taking Qinghai oil sludge (oil content 20wt%, water content 15wt%, solid content 65wt%, asphaltene content 2.5wt%) as an example, dodecylbenzenesulfonic acid (DBSA) was dissolved in cyclohexane to prepare DBSA-cyclohexane solutions of 0.5%, 1.0%, 1.5%, and 2.0% (0.5%, 1.0%, 1.5%, and 2.0% are the percentages of DBSA by mass relative to the total mass of the DBSA-cyclohexane solution). 1g of crude oil sludge was mixed with 1g of cyclohexane solutions of different concentrations and stirred at 500r / min for 30min. The mixture was then allowed to stand under gravity for 3min, and the lower solid phase particles were separated. The solid phase particles were washed with 0.5g of cyclohexane and placed in an 80℃ oven. The residual oil content of the solid phase particles after drying is shown in Table 7. The upper oil-bearing liquid phase was recovered by rotary evaporation, and the cyclohexane was reused.

[0087] Comparative Example 6

[0088] The procedure is the same as in Example 37, except that dodecylbenzenesulfonic acid (DBSA) is not added to prepare a 0% DBSA-cyclohexane solution. The residual oil content of the solid particles after drying is shown in Table 7.

[0089] Table 7 Residual oil content of solid particles after treatment

[0090] serial number DBSA concentration (%) Residual oil content in solid particles after drying (%) Comparative Example 6 0 2.70 Example 37 0.5 0.91 Example 38 1.0 0.92 Example 39 1.5 0.86 Example 40 2.0 0.89

[0091] Examples 37-40 and Comparative Example 6 investigated the effect of dodecylbenzenesulfonic acid (DBSA) dosage on the residual oil content of solid particles. After adding DBSA, the residual oil content of the solid particles decreased. This is because the sulfonic acid groups on DBSA form hydrogen bonds with the silanol groups on the particles, adsorbing onto the particles and providing repulsive forces between them, promoting particle dispersion and thus releasing asphaltenes, resulting in a decrease in the residual oil content of the solid particles. With increasing DBSA dosage, the residual oil content of the particles did not change significantly.

[0092] Examples 41-44

[0093] Taking Qinghai oil sludge (oil content 20wt%, water content 15wt%, solid content 65wt%, asphaltene content 2.5wt%) as an example. Fatty alcohol polyoxyethylene ether carboxylic acid C... 12 E9Ac is dissolved in cyclohexane to prepare 0.5%, 1.0%, 1.5%, and 2% C64 solutions. 12 E9Ac-cyclohexane solution (0.5%, 1.0%, 1.5% and 2% for C) 12 The mass of E9Ac accounts for C 12 (Percentage of total mass of E9Ac-cyclohexane solution) Take 1g of crude oil sludge and mix it with 1g of cyclohexane solution of different concentrations. Stir at 500r / min for 30min. Let the mixture stand under gravity for 3min. Separate the lower solid phase particles. Wash the solid phase particles with 0.5g of cyclohexane and place them in an 80℃ oven. The residual oil content of the solid phase particles after drying is shown in Table 8. The upper oil-carrying liquid phase is recovered by rotary evaporation and the cyclohexane is reused.

[0094] Comparative Example 7

[0095] The steps are the same as in Example 41, except that fatty alcohol polyoxyethylene ether carboxylic acid C is not added. 12 E9Ac, preparing 0% C 12 E9Ac-cyclohexane solution. The residual oil content of the solid particles after drying is shown in Table 8.

[0096] Table 8 Residual oil content of solid particles after treatment

[0097] serial number <![CDATA[C 12 E9Ac concentration (%) Residual oil content of dried particles (%) Comparative Example 7 0 1.33 Example 41 0.5 0.91 Example 42 1.0 0.59 Example 43 1.5 0.84 Example 44 2.0 0.80

[0098] Examples 41-44 and Comparative Example 7 investigated the effects of fatty alcohol polyoxyethylene ether carboxylic acid C. 12Effect of E9Ac dosage on residual oil content in solid particles; addition of C 12 After E9Ac, the residual oil content of solid particles decreased, which is due to C 12 The carboxyl and ethoxy groups on E9Ac form hydrogen bonds with the silanol groups on the particles, which are adsorbed onto the particles, providing repulsive forces between particles, promoting particle dispersion, thereby releasing asphaltenes and reducing the amount of residual oil in the solid phase particles. With C 12 With the increase in E9Ac dosage, the amount of residual particulate oil did not change significantly.

[0099] Examples 45-46

[0100] Take, for example, a low-quality oil sand from Canada (oil content 5.17 wt%, water content 4.44 wt%, solids content 90.39 wt%, bituminous content 0.50 wt%). Figure 2 As shown, the sample underwent a two-step solvent extraction. The first solvent extraction did not involve mineral particle agglomeration, and pure solvent extraction could separate coarse particles; the second extraction targeted the agglomerated fine particles in the sample. Dodecylbenzenesulfonic acid (DBSA) and fatty alcohol polyoxyethylene ether carboxylic acid (C) were used. 12 E9Ac was dissolved in cyclohexane to prepare a 0.5% DBSA-cyclohexane solution (0.5% being the percentage of DBSA by mass in the total DBSA-cyclohexane solution) and a 1% C solution. 12 E9Ac-cyclohexane solution (1% is C) 12 The mass of E9Ac accounts for C 12 (Percentage of total mass of E9Ac-cyclohexane solution) Take 1g of fine oil sand particles and 1g of cyclohexane solution with different particle dispersants and mix them separately. Stir at 500r / min for 30min. Separate the solid particles by settling the mixture under gravity for 10min. Wash the solid particles with 0.5g of cyclohexane and place them in an 80℃ oven. The residual oil content of the solid particles after drying is shown in Table 9. The upper oil-carrying liquid phase is recovered by rotary evaporation and the cyclohexane is reused.

[0101] Comparative Example 8

[0102] The steps are the same as in Example 45, except that no particulate dispersant is added during the second extraction. The residual oil content of the solid particles after drying is shown in Table 9.

[0103] Table 9 Residual oil content of solid particles after treatment

[0104] serial number Extraction solvent Residual oil content of solid particles after drying (%) Comparative Example 8 Cyclohexane 4.34 Example 45 0.5% DBSA-cyclohexane solution 0.89 Example 46 <![CDATA[1%C 12 E9Ac-cyclohexane solution]]> 0.84

[0105] Table 9 shows that during the secondary extraction, for agglomerated fine particles, the oil content of the solid particles is relatively high without the addition of a particulate dispersant. This is because the fine particles are highly aggregated at this time, and the bound asphaltenes cannot be released. The addition of particulate dispersants, dodecylbenzenesulfonic acid (DBSA) and fatty alcohol polyoxyethylene ether carboxylic acid (C), respectively... 12At E9Ac, dispersed particle aggregates release asphaltenes, thereby reducing the oil content.

[0106] Example 47

[0107] Taking a Canadian oil sand (oil content 10.7 wt%, water content 1.5 wt%, solid content 87.8 wt%, bituminous content 2.52 wt%) as an example, dodecylbenzenesulfonic acid (DBSA) was dissolved in cyclohexane to prepare a 0.5% DBSA-cyclohexane solution (0.5% is the percentage of DBSA by mass in the total mass of the DBSA-cyclohexane solution). 1 g of fine oil sand particles were mixed with 1 g of cyclohexane solution and stirred at 500 r / min for 30 min. The mixture was then allowed to settle under gravity for 5 min. The solid particles were washed with 0.5 g of cyclohexane and placed in an 80℃ oven. The residual oil content of the solid particles after drying is shown in Table 10. The upper oil-bearing liquid phase was rotary evaporated to recover crude oil and reuse cyclohexane.

[0108] Comparative Example 9

[0109] The steps are the same as in Example 47, except that no particulate dispersant is added during the second extraction. The residual oil content of the solid particles after drying is shown in Table 10.

[0110] Table 10 Residual oil content of solid particles after treatment

[0111] serial number Extraction solvent Residual oil content in solid particles after drying (%) Comparative Example 9 Cyclohexane 0.8 Example 47 0.5% DBSA-cyclohexane solution 0.068

[0112] The pattern shown in Table 10 is consistent with that in Table 9. During the secondary extraction, for agglomerated fine particles, the oil content of the solid particles is relatively high when no particle dispersant is added. This is because the fine particles are highly aggregated at this time, and the bound asphaltenes cannot be released. When the particle dispersant dodecylbenzenesulfonic acid (DBSA) is added, the particle aggregates are dispersed and the asphaltenes are released, thereby reducing the oil content.

[0113] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for solvent extraction of oil sludge / oil sands assisted by a particulate dispersant, comprising the following steps: The solution containing the particulate dispersant was mixed with oil sludge / oil sand, and solvent extraction was performed to separate the solid particles and the oil-carrying liquid phase. The solid particles are sequentially washed and dried; the washing solvent is a solvent for dissolving the particle dispersant. The particulate dispersant includes fatty alcohol polyoxyethylene ether carboxylic acid, fatty alcohol polyoxypropylene polyoxyethylene ether carboxylic acid, or dodecylbenzene sulfonic acid. The solvent used in the solution containing the particulate dispersant includes one of cycloalkanes and toluene; the cycloalkanes include cyclohexane and / or cyclopentane. The separation includes gravity sedimentation or centrifugation; the gravity sedimentation time is 0.5 to 60 minutes; the centrifugation speed is 800 to 2000 r / min, and the time is 3 to 30 minutes.

2. The solvent extraction method according to claim 1, characterized in that, The oil sludge / oil sand has an oil content of 5-30 wt%, a water content of 4-20 wt%, and a solid content of 57-92 wt%; the sum of all components is 100%.

3. The solvent extraction method according to claim 1 or 2, characterized in that, The mass ratio of the oil sludge / oil sand to the solution containing the particulate dispersant is 1:(0.5~3).

4. The solvent extraction method according to claim 1, characterized in that, The mass of the particulate dispersant is less than 2.5% of the mass of the solution containing the particulate dispersant.

5. The solvent extraction method according to claim 1, characterized in that, The solvent extraction is carried out under stirring conditions; the stirring speed is 300~2000 r / min, and the time is 10~120 min.

6. The solvent extraction method according to claim 1, characterized in that, The drying temperature is 70~110℃.

7. The solvent extraction method according to claim 6, characterized in that, After drying, the process further includes removing residual solvent by low-temperature thermal desorption of the dried solid particles; the temperature of the low-temperature thermal desorption is 250~350℃ and the time is 30~60min.

8. The solvent extraction method according to claim 1, characterized in that, After separating the oil-carrying liquid phase, the process further includes rotary evaporation of the oil-carrying liquid phase to obtain crude oil and solvent, respectively.

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