Metal-modulated hydrophobic deep eutectic solvent, and preparation method and application thereof

Abstract

A metal-regulated hydrophobic deep eutectic solvent and a preparation method and application thereof, step one: low water-soluble organic matter is respectively used as a hydrogen bond donor and a hydrogen bond acceptor, and stirring is carried out under the condition of a water bath at 40-80 DEG C, to obtain a series of HDES including bisphenol, phenol-fatty acid, fatty acid-organic alcohol or phenol-quaternary ammonium salt; step two: metal salt or metal oxide is added to the HDES, and continuous stirring is carried out, to obtain a metal-regulated hydrophobic deep eutectic solvent. According to the complexing ability of special hydrogen bond donor and acceptor to metal, the optimal metal and the regulation effect of the incorporation amount on the molecular size of HDES are screened, to obtain a novel metal-HDES combined solvent. With high oil-containing sludge or waste mineral oil as a treatment object, through the extraction of the metal-HDES combined solvent, efficient extraction of oil and selective separation of light oil are simultaneously realized.

Description

Technical Field

[0001] This invention belongs to the field of petrochemical environmental protection technology, and relates to a metal-controlled hydrophobic eutectic solvent, its preparation method and application. Background Technology

[0002] Oil-containing waste generated during crude oil extraction is a key target for resource recovery due to its high calorific value. Current treatment technologies mainly fall into two categories: low-temperature processes such as centrifugation or pressure filtration and freeze-thaw cycles, and medium- and high-temperature processes such as hot water / solvent washing and thermal desorption, all of which have made some progress. Although the production of recovered oil is gradually increasing, the oil phase still exhibits characteristics such as a wide range of carbon chain distribution and a relatively high proportion of heavy oil, resulting in a low direct utilization rate of recovered oil.

[0003] Distillation is a common technique in crude oil refining, separating components from different carbon ranges in the oil phase. However, the energy consumption required for fractionation is significant, and it can easily lead to the agglomeration of some organic compounds, increasing the content of heavy oil. Thermal cracking is an effective resource recovery technology that "shears" long-chain organic compounds and reduces the content of heavy components. The resulting organic compounds of different molecular weights are then condensed in multiple stages to achieve fractional oil recovery. While thermal cracking promotes the conversion of more heavy oil into light oil components, its high energy consumption makes it uneconomical. Therefore, based on the characteristics of oily waste, developing a low-energy, simple process for separating and recovering light oil, simultaneously achieving effective oil recovery and oil conditioning, is of great significance for improving the resource utilization rate of oily waste.

[0004] Extraction is a low-temperature, high-efficiency oil extraction process. With the growing emphasis on green and low-carbon technologies, traditional extractants are gradually being replaced by eutectic solvents. Although various types of eutectic solvents have been designed and researched, they still cannot achieve the selective recovery of higher-calorific-value components from oily waste. Adjusting the composition of DES materials and optimizing the intercomponent spacing based on the spatial distribution of DES and the molecular size characteristics of light oils will create a "filter" structure at the molecular scale, enabling the selective separation of light oils and enhancing the application prospects of DES. Summary of the Invention

[0005] Technical Problem Solved: This invention addresses the issue of low calorific value in oil extraction from existing oily waste treatment processes by proposing a metal-controlled hydrophobic eutectic solvent, its preparation method, and its application. This invention selects different types of low-water-soluble organic compounds such as phenols, fatty acids, organic alcohols, quaternary ammonium salts, and tertiary amines, and utilizes a simple low-temperature stirring method to obtain a series of eutectic solvents with excellent hydrophobic properties. Based on acid-base regulation, a compatible, hydrophobic-compatible HDES is obtained, achieving the recyclability of the extractant. Furthermore, based on the complexing ability of specific hydrogen bond donors and acceptors to metals, the optimal metal and its doping amount are screened to regulate the molecular size of HDES, resulting in a novel metal-HDES combined solvent. Using high-oil-content sludge or waste mineral oil as the treatment target, the metal-HDES combined solvent extraction simultaneously achieves efficient oil extraction and selective separation of light oils.

[0006] Technical solution: A method for preparing a metal-controlled hydrophobic eutectic solvent, comprising the following steps: Step 1: Using low water-soluble organic compounds as hydrogen bond donors and hydrogen bond acceptors respectively, wherein the molar ratio of hydrogen bond donors to hydrogen bond acceptors is (1-4):(1-5), stirring under a water bath at 40-80°C, to obtain a series of hydrophobic eutectic solvents (HDES) including bisphenols, phenol-fatty acids, fatty acids-organic alcohols, or phenol-quaternary ammonium salts; Step 2: Adding metal salts or metal oxides to the above HDES, and continuously stirring, to obtain a metal-controlled hydrophobic eutectic solvent.

[0007] The low water-soluble organic compounds in step one above include phenols, fatty acids, organic alcohols, quaternary ammonium salts, or tertiary amines.

[0008] In step two above, the metal salt or metal oxide is Fe, Zn, Cu, Ni, Mn, Co, Pt, Mo, La, Ce; and the molar ratio of the metal element to HDEs is (0.001~0.05):1.

[0009] The metal-controlled hydrophobic eutectic solvent prepared by the above method.

[0010] The above-mentioned metal-controlled hydrophobic eutectic solvents are used in the extraction of light components from oily waste.

[0011] The specific application method is as follows: add the metal-controlled hydrophobic eutectic solvent to the oily waste and stir to extract. According to the density difference, centrifuge to separate the solid residue, oil-HDES mixed phase and undissolved oil or oil flakes. The oil-HDES mixed phase is separated and then protonated and deprotonated using acid and alkali to achieve oil phase separation and recovery of the metal-controlled hydrophobic eutectic solvent.

[0012] The mass ratio of the above-mentioned metal-controlled hydrophobic eutectic solvent to oily waste is (1-12):1; the centrifugation rate is 1000-12000 rpm and the time is 10-120 min.

[0013] The agent that promotes the protonation of HDES is a 0.5-6 mol / L NaOH solution, and the agent that promotes the deprotonation of HDES is pure acetic acid or carbon dioxide gas. The molar ratio of NaOH solution: deprotonating agent: oil-HDES mixed solution is 1:1:0.5-1.

[0014] Beneficial effects: 1) Utilizing the similarity between green and low-toxic HDES and the non-polar properties of oil, the oil phase in oily waste can be extracted and recovered; 2) Using large-sized, low-water-soluble organic matter as hydrogen bond donors for HDES can expand the intermolecular distance of HDES and increase the storage capacity for oil; 3) By optimizing the complexation of metals with HDES components, the local molecular size can be controlled to prevent the dissolution of large-molecule heavy oil into the intermolecular space of HDES, thus achieving selective extraction of light oil; 4) Optimizing the types and ratios of low-water-soluble hydrogen bond donors and acceptors makes the combined HDES suitable for acid-base controlled hydrophilic-hydrophobic conversion, facilitating oil phase separation and HDES recycling and reuse. Detailed Implementation

[0015] The oily waste from a petrochemical refinery in Nanjing was used as the treatment target. Its oil content was 65 wt.%, water content was 14 wt.%, and slag content was 21 wt.%.

[0016] The present invention will be further described in detail below with reference to specific embodiments, but the present invention is not limited thereto.

[0017] Example 1

[0018] A method for extraction and separation of metal-controlled hydrophobic eutectic solvents and oily waste, comprising the following steps:

[0019] (1) Mix thymol and octanoic acid at a molar ratio of 1:1 and stir in a water bath at 60°C to form a homogeneous, transparent liquid mixture: thymol-octanoic acid hydrophobic eutectic solvent (HDES).

[0020] (2) Weigh ferric chloride according to the mass ratio of metal salt to HDES of 0.007:1, transfer it to the homogeneous phase of thymol-octanoic acid HDES, stir evenly to dissolve the metal salt, and obtain the metal Fe-HDES combined extractant.

[0021] (3) Add the combined extractant to the high-oil-content waste at an extractant:high-oil-content waste ratio of 7:1 and stir at 60°C for 60 min. After extraction, centrifuge the mixed phase solution at 4000 rpm for 60 min. Carefully separate the oil-HDES mixed phase according to the original HDES volume, and use the remaining solid residue for oil content testing.

[0022] (4) Based on the total molar fraction of phenolic hydroxyl groups and fatty acid carboxyl groups in the extractant, add 5 mol / L NaOH solution at a molar ratio of 1:1 to promote the conversion of HDES to hydrophilic substances, thereby achieving the separation of the oil phase and protonated HDES. Add acetic acid in an equal molar amount to NaOH to the protonated HDES to promote the recovery of hydrophobic phenolic-fatty acid HDES.

[0023] (5) In accordance with the relevant oily waste testing standards, analyze and calculate the oil content of the separated residual oily waste and the distribution of the four phases of the recovered oil. The oil removal rate was 80%, and the proportions of saturated hydrocarbons, aromatic hydrocarbons, gums, and asphaltenes in the recovered oil were 50.5%, 13.7%, 14.4%, and 21.4%, respectively.

[0024] Example 2

[0025] A method for extraction and separation of metal-controlled hydrophobic eutectic solvents and oily waste, comprising the following steps:

[0026] (1) Ethyl maltol and n-octanoic acid are mixed at a molar ratio of 1:3 and stirred in a water bath at 60°C to form a homogeneous, transparent liquid mixture, which is the ethyl maltol-n-octanoic acid hydrophobic eutectic solvent (HDES).

[0027] (2) Weigh ferric chloride according to the mass ratio of metal salt to HDES of 0.007:1, transfer it to the homogeneous phase of ethyl maltol-octanoic acid HDES, stir evenly to dissolve the metal salt, and obtain the metal Fe-HDES combined extractant.

[0028] (3) Add the combined extractant to the high-oil-content waste at an extractant:high-oil-content waste ratio of 7:1 and stir at 60°C for 60 min. After extraction, centrifuge the mixed phase solution at 4000 rpm for 60 min. Carefully separate the oil-HDES mixed phase according to the original HDES volume, and use the remaining solid residue for oil content testing.

[0029] (4) Based on the total molar fraction of phenolic hydroxyl groups and fatty acid carboxyl groups in the extractant, add 5 mol / L NaOH solution at a molar ratio of 1:1 to promote the conversion of HDES to hydrophilic substances, thereby achieving the separation of the oil phase and protonated HDES. Add acetic acid in an equal molar amount to NaOH to the protonated HDES to promote the recovery of hydrophobic phenolic-fatty acid HDES.

[0030] (5) In accordance with the relevant oily waste testing standards, the oil content of the separated residual oily waste and the distribution of the four phases of the recovered oil were analyzed and calculated. The oil removal rate was 85%, and the proportions of saturated hydrocarbons, aromatic hydrocarbons, gums, and asphaltenes in the recovered oil were 58.7%, 18.8%, 7.2%, and 15.3%, respectively.

[0031] Example 3

[0032] A method for extraction and separation of metal-controlled hydrophobic eutectic solvents and oily waste, comprising the following steps:

[0033] (1) Eugenol and lauric acid are mixed at a molar ratio of 4:1 (due to the difference in HDES types, only at this ratio can a eutectic solution be formed at room temperature). The mixture is stirred in a 60°C water bath to form a homogeneous, transparent liquid mixture, which is the eugenol-lauric acid hydrophobic eutectic solvent (HDES).

[0034] (2) Weigh ferric chloride according to the mass ratio of metal salt to HDES of 0.007:1, transfer it to the homogeneous phase of eugenol-lauric acid HDES, stir evenly to dissolve the metal salt, and obtain the metal Fe-HDES combined extractant.

[0035] (3) Add the combined extractant to the high-oil-content waste at an extractant:high-oil-content waste ratio of 7:1 and stir at 60°C for 60 min. After extraction, centrifuge the mixed phase solution at 4000 rpm for 60 min. Carefully separate the oil-HDES mixed phase according to the original HDES volume, and use the remaining solid residue for oil content testing.

[0036] (4) Based on the total molar fraction of phenolic hydroxyl groups and fatty acid carboxyl groups in the extractant, add 5 mol / L NaOH solution at a molar ratio of 1:1 to promote the conversion of HDES to hydrophilic substances, thereby achieving the separation of the oil phase and protonated HDES. Add acetic acid in an equal molar amount to NaOH to the protonated HDES to promote the recovery of hydrophobic phenolic-fatty acid HDES.

[0037] (5) In accordance with the relevant oily waste testing standards, the oil content of the separated residual oily waste and the distribution of the four phases of the recovered oil were analyzed and calculated. The oil removal rate was 77%, and the proportions of saturated hydrocarbons, aromatic hydrocarbons, gums, and asphaltenes in the recovered oil were 47.5%, 16.4%, 15.3%, and 20.8%, respectively.

[0038] Example 4

[0039] A method for extraction and separation of metal-controlled hydrophobic eutectic solvents and oily waste, comprising the following steps:

[0040] (1) Ethyl maltol and n-octanoic acid are mixed at a molar ratio of 1:5 and stirred in a water bath at 60°C to form a homogeneous, transparent liquid mixture, which is the ethyl maltol-n-octanoic acid hydrophobic eutectic solvent (HDES).

[0041] (2) Weigh zinc chloride according to the mass ratio of metal salt to HDES of 0.003:1, transfer it to the homogeneous phase of ethyl maltol-octanoic acid HDES, stir evenly to dissolve the metal salt, and obtain the metal Zn-HDES combined extractant.

[0042] (3) Add the combined extractant to the high-oil-content waste at an extractant:high-oil-content waste ratio of 5:1 and stir at 60°C for 60 min. After extraction, centrifuge the mixed phase solution at 4000 rpm for 60 min. Carefully separate the oil-HDES mixed phase according to the original HDES volume, and use the remaining solid residue for oil content testing.

[0043] (4) Based on the total molar fraction of phenolic hydroxyl groups and fatty acid carboxyl groups in the extractant, add 5 mol / L NaOH solution at a molar ratio of 1:1 to promote the conversion of HDES to hydrophilic substances, thereby achieving the separation of the oil phase and protonated HDES. Add acetic acid in an equal molar amount to NaOH to the protonated HDES to promote the recovery of hydrophobic phenolic-fatty acid HDES.

[0044] (5) In accordance with the relevant oily waste testing standards, the oil content of the separated residual oily waste and the distribution of the four phases of the recovered oil were analyzed and calculated. The oil removal rate was 78%, and the proportions of saturated hydrocarbons, aromatic hydrocarbons, gums, and asphaltenes in the recovered oil were 51.2%, 15.7%, 11.5%, and 21.6%, respectively.

[0045] Example 5

[0046] A method for extraction and separation of metal-controlled hydrophobic eutectic solvents and oily waste, comprising the following steps:

[0047] (1) Ethyl maltol and n-octanoic acid are mixed at a molar ratio of 1:3 and stirred in a water bath at 60°C to form a homogeneous, transparent liquid mixture, which is the ethyl maltol-n-octanoic acid hydrophobic eutectic solvent (HDES).

[0048] (2) Add the combined extractant to the high-oil-content waste at an extractant:high-oil-content waste ratio of 7:1 and stir at 60°C for 60 min. After extraction, centrifuge the mixed phase solution at 4000 rpm for 60 min. Carefully separate the oil-HDES mixed phase according to the original HDES volume, and use the remaining solid residue for oil content testing.

[0049] (3) Based on the total molar fraction of phenolic hydroxyl groups and fatty acid carboxyl groups in the extractant, add 5 mol / L NaOH solution at a molar ratio of 1:1 to promote the conversion of HDES to hydrophilic substances, thereby achieving the separation of the oil phase and protonated HDES. Add acetic acid in an equal molar amount to NaOH to the protonated HDES to promote the recovery of hydrophobic phenolic-fatty acid HDES.

[0050] (4) In accordance with the relevant oily waste testing standards, the oil content of the separated residual oily waste and the distribution of the four phases of the recovered oil were analyzed and calculated. The oil removal rate was 88%, and the proportions of saturated hydrocarbons, aromatic hydrocarbons, gums, and asphaltenes in the recovered oil were 40.3%, 19.2%, 15.6%, and 24.9%, respectively.

[0051] Example 6

[0052] A method for extraction and separation of metal-controlled hydrophobic eutectic solvents and oily waste, comprising the following steps:

[0053] (1) Lauric acid and thymol are mixed at a molar ratio of 0.8:1 and stirred in a water bath at 60°C to form a homogeneous, transparent liquid mixture, which is the lauric acid-thymol hydrophobic eutectic solvent (HDES).

[0054] (2) Add the combined extractant to the high-oil-content waste at an extractant:high-oil-content waste ratio of 7:1 and stir at 60°C for 60 min. After extraction, centrifuge the mixed phase solution at 4000 rpm for 60 min. Carefully separate the oil-HDES mixed phase according to the original HDES volume, and use the remaining solid residue for oil content testing.

[0055] (3) Based on the total molar fraction of phenolic hydroxyl and carboxyl groups in the extractant, add 5 mol / L NaOH solution at a molar ratio of 1:1 to promote the conversion of HDES to hydrophilic substances, thereby achieving the separation of the oil phase and protonated HDES. Add acetic acid in an equal molar amount to NaOH to the protonated HDES to promote the recovery of hydrophobic HDES.

[0056] (4) In accordance with the relevant oily waste testing standards, the oil content of the separated residual oily waste and the distribution of the four phases of the recovered oil were analyzed and calculated. The oil removal rate was 79%, and the proportions of saturated hydrocarbons, aromatic hydrocarbons, gums, and asphaltenes in the recovered oil were 37.4%, 20.6%, 15.2%, and 26.8%, respectively.

[0057] Table 1. Distribution of four-phase components in oily waste and HDES recovered oil.

[0058]

[0059] The above embodiments are only used to illustrate the technical methods proposed in this invention, but this invention is not limited to the above embodiments 1-6. If those skilled in the art are inspired by these embodiments and make direct modifications to this invention, they should all fall within the protection scope of this invention.

Claims

1. The application of metal-controlled hydrophobic eutectic solvents in the extraction of light components from oily waste, characterized in that, The preparation steps of the metal-controlled hydrophobic eutectic solvent are as follows: (1) Ethyl maltol and n-octanoic acid are mixed at a molar ratio of 1:3 and stirred in a water bath at 60°C to form a homogeneous, transparent liquid mixture, which is the ethyl maltol-n-octanoic acid hydrophobic eutectic solvent HDES; (2) Ferric chloride is weighed according to the mass ratio of metal salt to ethyl maltol-n-octanoic acid hydrophobic eutectic solvent HDES of 0.007:1, and transferred to the homogeneous ethyl maltol-n-octanoic acid hydrophobic eutectic solvent HDES. The mixture is stirred evenly to dissolve the metal salt and obtain the metal-controlled hydrophobic eutectic solvent. A metal-controlled hydrophobic eutectic solvent was added to the oily waste at a ratio of 7:1, and the mixture was stirred at 60°C for 60 min. After extraction, the mixed phase solution was centrifuged at 4000 rpm for 60 min. The oil-HDES mixed phase was carefully separated according to the original HDES volume, and the remaining solid residue was used for oil content testing. Based on the total molar fraction of phenolic hydroxyl groups and fatty acid carboxyl groups in the metal-controlled hydrophobic eutectic solvent, 5 mol / L NaOH solution was added at a molar ratio of 1:1 to promote the conversion of HDES to hydrophilic substances, thereby achieving the separation of the oil phase and protonated HDES.

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