Preparation and application of difunctional low-temperature demulsifier prepared by modifying polysuccinimide

Abstract

The invention relates to a bifunctional low-temperature demulsifier prepared by modifying polysuccinimide, the low-temperature demulsifier is an amphiphilic polysuccinimide derivative obtained by one-step reaction of polysuccinimide and primary amine, and the main chain of the amphiphilic polysuccinimide derivative is a strong-polarity polyamide group. According to preparation and application of the difunctional low-temperature demulsifier prepared through polysuccinimide modification, aiming at the problems that an existing reverse demulsifier is low in demulsification efficiency, long in time and high in temperature and a product has certain toxicity, a fully-degradable high-polarity low-temperature directional demulsifier is designed with environment-friendly high-molecular polysuccinimide as a raw material and primary amine as a modification reagent; the polysuccinimide is wide in source and low in price, the polysuccinimide reacts with primary amine, the demulsification efficiency of the agent is improved by adjusting the aromaticity of the demulsifier, the water purification capacity of the agent is improved by optimizing the chain length of side chain alkyl, the modified polyamide demulsifier is a green polymer, and the demulsification efficiency is improved. And the application prospect is promising.

Description

Technical Field

[0001] The invention relates to the technical field of oilfield chemicals and functional polymer synthesis, in particular to the preparation and application of a bifunctional low-temperature demulsifier prepared by modifying polysuccinimide. Background Art

[0002] At present, the market size of oily wastewater treatment industry in my country is close to 100 billion yuan, among which the cost of treating wastewater in crude oil extraction and petroleum processing accounts for more than 90% of the market share. Oily wastewater can be divided into three categories according to the existence form of oil in wastewater, namely floating oil, emulsified oil and dissolved oil. Floating oil can be separated by static sedimentation, while emulsified and dissolved oil must first be demulsified and then allowed to stand or be filtered to separate the oil substances. Usually, the demulsification technologies for emulsified oily wastewater mainly include: physical method, chemical method, biological method and a combination of multiple technologies. The chemical demulsification method adds chemical agents to replace the oil-water interface membrane through solubilization, compresses the double electrical layer of droplets, and promotes the aggregation and separation of dispersed oil droplets. It is the most efficient and economical emulsified wastewater treatment technology.

[0003] Although chemical demulsifiers have been used for a hundred years, from the initial inorganic salts to the currently widely used polymer demulsifiers, the existing polymer demulsifiers are mainly water-in-oil (W / O) demulsifiers, and there are relatively few O / W demulsifiers reported. For example, polyamide-amine macromolecular demulsifiers prepared by multi-step reactions using ethylenediamine as the initiator core (CN105273201B), polyacrylamide (Can. J. Chem. Eng. 94 (12), 2298–2302) and magnetic modified polymer demulsifiers (CN110613960B) have an operating temperature of 30 to 80°C and a demulsification time of 10 to 150 minutes, but they cannot achieve low-temperature rapid demulsification. Therefore, research and development of new chemical structure demulsifiers to improve the demulsification efficiency of the agent, reduce the demulsification temperature, and increase universality have become important issues in the development of oilfield chemicals.

[0004] Recently, we reported that amino acid cyclic anhydride (NCA) was prepared from natural amino acid monomers, and then a high molecular weight polyamino acid low-temperature demulsifier was prepared by ring-opening polymerization (CN114774158B and Fuel, 2024, 365: 131237). It has the characteristics of low temperature, high efficiency, and green environmental protection. However, the process of preparing highly polar and highly aromatic polyamino acid demulsifiers by ring-opening polymerization of amino acid NCA is complicated and difficult to synthesize on a large scale. Polysuccinimide, as a kind of environmentally friendly polymer, can be prepared by aspartic acid or maleic anhydride. The literature reports that the primary amine-modified polysuccinimide is prepared by ring-opening with a main chain of a highly polar polyamide skeleton. Degradable polymers are widely used in the fields of drug delivery and so on. Therefore, using polysuccinimide and target primary amine as raw materials, by selecting the primary amine category to regulate the hydrophilicity and aromaticity of the modified polysuccinimide derivatives, it is expected to prepare a type of high molecular weight low-temperature O / W type demulsifier with a main chain of a highly polar polyamide skeleton and a side chain of an alkyl chain or an aromatic ring. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention provides a preparation and application of a bifunctional low-temperature demulsifier prepared by modification of polysuccinimide, which has the advantages of good demulsification effect, etc., and solves the problems of low demulsification efficiency, high demulsification temperature, long demulsification time and certain toxicity of traditional polyether demulsifiers.

[0006] To achieve the above object, the present invention provides the following technical solution: a bifunctional low-temperature demulsifier prepared by modifying polysuccinimide, wherein the low-temperature demulsifier is an amphiphilic polysuccinimide derivative obtained by a one-step reaction of polysuccinimide and a primary amine, wherein the main chain is a strongly polar polyamide group, and the side chain (primary amine) can be designed and introduced according to the properties of the emulsion:

[0007] a. Dimethylaminopropylamine-modified polysuccinimide (PS I-TA) prepared by single grafting of dimethylaminopropylamine

[0008]

[0009] b. Dimethylaminopropylamine dopamine co-modified polysuccinimide (PS I-DA-TA)

[0010]

[0011] c. Dimethylaminopropylamine phenylethylamine step-grafted polysuccinimide (PS I-PEA-TA-2)

[0012]

[0013] d. One-step co-modification of polysuccinimide with dimethylaminopropylamine and phenylethylamine (PS I-PEA-TA)

[0014]

[0015] Furthermore, the grafting rate of the primary amine is 50% to 100%, and the grafting reaction is a one-step or two-step process to prepare the target product.

[0016] Furthermore, the infrared spectrum of the polysuccinimide-modified derivative shows an obvious amide structure absorption peak, and the nuclear magnetic hydrogen spectrum shows an obvious amide characteristic chemical shift of the side chain.

[0017] Furthermore, the modified monomer is one of primary amine, 3-dimethylaminopropylamine, dopamine hydrochloride and β-phenylethylamine, or a combination of aliphatic primary amine and aromatic primary amine, and the molecular weight of the polysuccinimide is not less than 7000-8000, and the purity is industrial grade or above.

[0018] A method for preparing a dimethylaminopropylamine modified polysuccinimide demulsifier, which is used to prepare the above-mentioned bifunctional low-temperature demulsifier prepared by modifying polysuccinimide, comprises the following steps:

[0019] Step 1: dissolving polysuccinimide in dimethyl sulfoxide (DMSO) at a mass ratio of polysuccinimide to DMSO of 1:(10-15), and stirring thoroughly under nitrogen until completely dissolved;

[0020] Step 2: Weigh a certain amount of dimethylaminopropylamine into the obtained polysuccinimide solution, so that the ratio of its amount to polysuccinimide is maintained in the range of nPS I:nTA=1:50-100, and stir it thoroughly to dissolve it to obtain a mixed solution;

[0021] Step 3: Heat the mixed solution in step 2 to 40-50°C and stir for 6-30h to obtain a brown viscous liquid;

[0022] Step 4: Use a precipitant to precipitate and separate the reaction solution in step 3, wash and dry the filter residue to obtain the polysuccinimide modified low-temperature demulsifier, and the mass ratio of the precipitant to the reaction solution is (1-5):1.

[0023] According to the above-mentioned bifunctional low-temperature demulsifier prepared by modification of polysuccinimide, a method for preparing a polysuccinimide demulsifier of dimethylaminopropylamine dopamine co-modified polysuccinimide and dimethylaminopropylamine phenethylamine step-grafted polysuccinimide comprises the following steps:

[0024] Step 1: dissolving polysuccinimide in dimethyl sulfoxide (DMSO) at a mass ratio of polysuccinimide to DMSO of 1:(10-15), and stirring thoroughly under nitrogen until completely dissolved;

[0025] Step 2: Weigh a certain amount of dopamine and phenylethylamine in the obtained polysuccinimide solution so that the ratio of the primary amine to the polysuccinimide substance is maintained within the range of nPS I:nTA=1:20-80, and stir it thoroughly to dissolve it to obtain a mixed solution;

[0026] Step 3: Heat the mixed solution in step 2 to 40-50° C. and stir for 12-30 hours, add dimethylaminopropylamine so that the ratio of dimethylaminopropylamine to dopamine or phenylethylamine is maintained at nTA:nDA / PEA=2-8, and continue to stir sufficiently to obtain a brown viscous liquid;

[0027] Step 4: Use a precipitant to precipitate and separate the reaction solution in step 3, wash and dry the filter residue to obtain the polysuccinimide modified low-temperature demulsifier, and the mass ratio of the precipitant to the reaction solution is (1-5):1.

[0028] According to the above-mentioned bifunctional low-temperature demulsifier prepared by modification of polysuccinimide, a method for preparing a polysuccinimide demulsifier modified by dimethylaminopropylamine and phenylethylamine in one step comprises the following steps:

[0029] Step 1: dissolving polysuccinimide in dimethyl sulfoxide (DMSO) at a mass ratio of polysuccinimide to DMSO of 1:(10-15), and stirring thoroughly under nitrogen until completely dissolved;

[0030] Step 2: The obtained polysuccinimide solution is weighed with a certain amount of dimethylaminopropylamine and phenylethylamine, so that the ratio of the primary amine to the polysuccinimide substance is maintained in the range of nPSI:nTA=1:50-100, and the ratio of the dimethylaminopropylamine to the phenylethylamine substance is maintained in the range of nTA:nPEA=1:0-0.8, and the mixture is stirred sufficiently to dissolve, thereby obtaining a mixed solution;

[0031] Step 3: Heat the mixed solution in step 2 to 40-50°C and stir for 6-30h to obtain a brown viscous liquid;

[0032] Step 4: Use a precipitant to precipitate and separate the reaction solution in step 3, wash and dry the filter residue to obtain the polysuccinimide modified low-temperature demulsifier, and the mass ratio of the precipitant to the reaction solution is (1-5):1.

[0033] Furthermore, the solid sample is obtained by vacuum drying or freeze drying at 50°C.

[0034] Furthermore, the main chain is a highly polar polyamide skeleton, and the grafted side chain is a hydrophobic alkyl chain or contains an alkyl chain and an aromatic ring at the same time, which has excellent interfacial activity. The flocculation and aggregation ability of the demulsifier can be regulated by regulating the length of the alkyl primary amine. It is degradable and can effectively inhibit the scaling of calcium and magnesium ions. It is not only an excellent O / W type demulsifier but also has scale inhibition ability.

[0035] The invention discloses an application of a bifunctional low-temperature demulsifier prepared by modifying polysuccinimide in the fields of crude oil demulsifier and emulsified oily wastewater treatment.

[0036] Compared with the prior art, the technical solution of this application has the following beneficial effects:

[0037] 1. The preparation and application of the bifunctional low-temperature demulsifier prepared by modification of polysuccinimide. Aiming at the low demulsification efficiency, long time, high temperature and certain toxicity of the products of the existing reverse demulsifier, a fully degradable strong polar low-temperature directional demulsifier is designed with environmentally friendly polymer polysuccinimide raw materials and primary amines as modification reagents. Polysuccinimide is widely available, low-priced, fully degradable, and will not cause secondary pollution to the environment.

[0038] 2. The preparation and application of the bifunctional low-temperature demulsifier prepared by modification of polysuccinimide. The amphiphilic strong polar polyamide polymer demulsifier is prepared by the reaction of polysuccinimide and primary amine. The demulsification efficiency of the agent is improved by adjusting the aromaticity of the demulsifier, and the water purification ability of the agent is improved by optimizing the length of the side chain alkyl chain. The modified polyamide demulsifier is a green polymer with great application prospects.

[0039] 3. Preparation and application of the bifunctional low-temperature demulsifier prepared by modifying polysuccinimide. The modified polyamide demulsifier has scale inhibition ability and can effectively inhibit calcium ion precipitation. The main chain polyamide can be spontaneously degraded. If it is retained in the water phase after demulsification, it will not cause secondary pollution to the water body. The polyamide demulsifier prepared by modified polysuccinimide has the characteristics of high efficiency, low temperature and universal applicability, low dosage and simple operation. The target demulsifier is simple to synthesize and is suitable for large-scale production and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a schematic diagram of the basic structural formula of the demulsifier of the present invention;

[0041] Figure 2 It is a schematic flow chart of the method for preparing the demulsifier of the present invention;

[0042] Figure 3 The infrared spectra of the synthetic demulsifiers of Examples 1, 2, 3, and 4 are shown;

[0043] Figure 4 The NMR hydrogen spectra of the demulsifiers synthesized in Examples 1, 2, 3, and 4 are shown;

[0044] Figure 5 It is the demulsification effect diagram of Examples 1, 2, 3, and 4;

[0045] Figure 6 Demulsification efficiency of synthetic demulsifiers of Examples 1, 2, 3, and 4 on emulsions with different oil contents;

[0046] Figure 7 The scale inhibition efficiency of the synthetic demulsifiers of Examples 1, 2, 3, and 4 against calcium ions. DETAILED DESCRIPTION

[0047] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0048] See also Figure 1 In this embodiment, a bifunctional low-temperature demulsifier prepared by modifying polysuccinimide is prepared. The low-temperature demulsifier is obtained by a one-step reaction of polysuccinimide and a primary amine to obtain an amphiphilic polysuccinimide derivative, the main chain of which is a strongly polar polyamide group, and the side chain (primary amine) can be designed and introduced according to the properties of the emulsion:

[0049] a. Dimethylaminopropylamine-modified polysuccinimide (PS I-TA) prepared by single grafting of dimethylaminopropylamine

[0050]

[0051] b. Dimethylaminopropylamine dopamine co-modified polysuccinimide (PS I-DA-TA)

[0052]

[0053] c. Dimethylaminopropylamine phenylethylamine step-grafted polysuccinimide (PS I-PEA-TA-2)

[0054]

[0055] d. One-step co-modification of polysuccinimide with dimethylaminopropylamine and phenylethylamine (PS I-PEA-TA)

[0056]

[0057] The grafting rate of the primary amine is 50% to 100%, and the grafting reaction is one step or two steps to achieve the preparation of the target product.

[0058] The infrared spectrum of the polysuccinimide-modified derivatives showed obvious amide structure absorption peaks, and the nuclear magnetic hydrogen spectrum showed obvious amide characteristic chemical shifts of the side chains.

[0059] The modified monomer is one of primary amine, 3-dimethylaminopropylamine, dopamine hydrochloride and β-phenylethylamine, or a combination of aliphatic primary amine and aromatic primary amine. The molecular weight of polysuccinimide is not less than 7000-8000, and the purity is industrial grade or above.

[0060] The main chain is a highly polar polyamide skeleton, and the grafted side chains are hydrophobic alkyl chains or contain both alkyl chains and aromatic rings. It has excellent interfacial activity. The flocculation and aggregation ability of the demulsifier can be regulated by adjusting the length of the alkyl primary amine. It is degradable and can effectively inhibit the scaling of calcium and magnesium ions. It is not only an excellent O / W type demulsifier but also has scale inhibition ability.

[0061] See also Figure 2 The preparation method of a dimethylaminopropylamine modified polysuccinimide demulsifier in this embodiment comprises the following steps:

[0062] Step 1: dissolving polysuccinimide in dimethyl sulfoxide (DMSO) at a mass ratio of polysuccinimide to DMSO of 1:(10-15), and stirring thoroughly under nitrogen until completely dissolved;

[0063] Step 2: Weigh a certain amount of dimethylaminopropylamine into the obtained polysuccinimide solution, so that the ratio of its amount to polysuccinimide is maintained in the range of nPS I:nTA=1:50-100, and stir it thoroughly to dissolve it to obtain a mixed solution;

[0064] Step 3: Heat the mixed solution in step 2 to 40-50°C and stir for 6-30h to obtain a brown viscous liquid;

[0065] Step 4: Use a precipitant to precipitate and separate the reaction solution in step 3, wash and dry the filter residue to obtain a polysuccinimide-modified low-temperature demulsifier, and the mass ratio of the precipitant to the reaction solution is (1-5):1.

[0066] A method for preparing a polysuccinimide demulsifier co-modified with dimethylaminopropylamine and dopamine and a polysuccinimide demulsifier grafted with dimethylaminopropylamine and phenethylamine in steps, comprising the following steps:

[0067] Step 1: dissolving polysuccinimide in dimethyl sulfoxide (DMSO) at a mass ratio of polysuccinimide to DMSO of 1:(10-15), and stirring thoroughly under nitrogen until completely dissolved;

[0068] Step 2: The obtained polysuccinimide solution is weighed with a certain amount of dopamine and phenylethylamine, so that the ratio of the primary amine to the polysuccinimide substance is maintained in the range of nPSI:nTA=1:20-80, and is fully stirred to dissolve, thereby obtaining a mixed solution;

[0069] Step 3: Heat the mixed solution in step 2 to 40-50° C. and stir for 12-30 hours, add dimethylaminopropylamine so that the ratio of dimethylaminopropylamine to dopamine or phenylethylamine is maintained at nTA:nDA / PEA=2-8, and continue to stir sufficiently to obtain a brown viscous liquid;

[0070] Step 4: Use a precipitant to precipitate and separate the reaction solution in step 3, wash and dry the filter residue to obtain a polysuccinimide-modified low-temperature demulsifier, and the mass ratio of the precipitant to the reaction solution is (1-5):1.

[0071] A method for preparing a one-step co-modified polysuccinimide demulsifier of dimethylaminopropylamine and phenethylamine comprises the following steps:

[0072] Step 1: dissolving polysuccinimide in dimethyl sulfoxide (DMSO) at a mass ratio of polysuccinimide to DMSO of 1:(10-15), and stirring thoroughly under nitrogen until completely dissolved;

[0073] Step 2: The obtained polysuccinimide solution is weighed with a certain amount of dimethylaminopropylamine and phenylethylamine, so that the ratio of the primary amine to the polysuccinimide substance is maintained in the range of nPSI:nTA=1:50-100, and the ratio of the dimethylaminopropylamine to the phenylethylamine substance is maintained in the range of nTA:nPEA=1:0-0.8, and the mixture is stirred sufficiently to dissolve, thereby obtaining a mixed solution;

[0074] Step 3: Heat the mixed solution in step 2 to 40-50°C and stir for 6-30h to obtain a brown viscous liquid;

[0075] Step 4: Use a precipitant to precipitate and separate the reaction solution in step 3, wash and dry the filter residue to obtain a polysuccinimide-modified low-temperature demulsifier, and the mass ratio of the precipitant to the reaction solution is (1-5):1.

[0076] The solid sample is obtained by vacuum drying or freeze drying at 50°C.

[0077] The invention discloses an application of a bifunctional low-temperature demulsifier prepared by modifying polysuccinimide in the fields of crude oil demulsifier and emulsified oily wastewater treatment.

[0078] In the following examples, the raw materials used were purchased from Shanghai MacLean Biochemical Technology Co., Ltd.; polysuccinimide with a molecular weight of 7000-8000, 3-dimethylaminopropylamine 99%, 1,3-propane sultone 99%, dopamine hydrochloride 98%, β-phenylethylamine 98%, and dimethyl sulfoxide AR.

[0079] Example 1

[0080] The preparation method is as follows:

[0081] Take the preparation of PSI-TA by complete grafting of polysuccinimide with dimethylaminopropylamine as an example: according to the molecular weight of polysuccinimide, its degree of polymerization is calculated to be about 80. In order to achieve 100% grafting, 0.98g of polysuccinimide and 1.0g of 3-dimethylaminopropylamine are weighed and added with 12.0mL of dimethyl sulfoxide (DMSO). After stirring and reacting at 60°C for 24h, a brown viscous liquid is obtained. Acetone or anhydrous ethanol (V; V=200mL) is used as a precipitant and vigorously stirred until the product is no longer viscous. Then, 2.0g of light brown powder PSI-TA is obtained after freeze-drying (yield: 99.9%). The preparation methods of PSI-DA and PSI-PEA are the same as above, and the reaction substrates are 0.98g of polysuccinimide and 1.6g of dopamine or 1.2g of phenylethylamine, respectively.

[0082] The infrared spectrum of polysuccinimide PSI-TA modified with dimethylaminopropylamine is shown in Figure 3 From the infrared spectrum of PSI-TA, the infrared absorption peak originally belonging to the polysuccinimide ring structure disappeared, and obvious amide structure absorption peaks appeared at 1658 and 1538 cm-1, indicating that 3-dimethylaminopropylamine was successfully introduced into the polysuccinimide polymer chain in the form of a side group after the ring-opening reaction. After NMR analysis ( Figure 4 ), indicating that the polysuccinimide has been completely ring-opened and amidated, and the grafting rate of different functional groups can be calculated to be 100.0% based on the integrated area of ​​the proton peak.

[0083] According to the "SY / T5797-1993 Crude Oil Demulsifier Performance Test Method (Bottle Test Method)", the demulsification performance of different samples was evaluated. First, DMSO was used as a solvent to prepare a 10 mg / mL sample solution, 25 mL of emulsion was added to a colorimetric tube, and then a certain dose of sample solution was added and vigorously shaken 200 times to make the demulsifier sample evenly dispersed in the emulsion. After standing for 20 minutes, the demulsification effect was observed and recorded. 5 mL of the lower aqueous phase of the emulsion after demulsification was taken with a syringe with a long needle, and extracted three times with petroleum ether with a boiling range of 90-120 ° C, and the volume was fixed to a certain volume. Finally, the absorbance of the petroleum ether extract was determined with a UV spectrophotometer, and finally converted to the oil content in the demulsified water through the standard curve of crude oil content and its absorbance, and then the demulsification efficiency was calculated.

[0084] First prepare a 10.0 mg / mL PSI-TA DMSO demulsification sample solution, add the above demulsifier to 5.0 wt% O / W emulsion (the oil phase is crude oil, pH = 6, the oil content is 50.0 g / L, and the average size of the oil droplets is about 1.0-3.0 μm). When the demulsifier dosage reaches 50 mg / L, the oil removal rate is 99.8%, and the demulsification temperature is a specific temperature specifically specified, and the experiment is carried out at room temperature.

[0085] Example 2

[0086] The preparation method is as follows:

[0087] The preparation method of co-grafted PSI-DA-TA is as follows: weigh 0.98g of polysuccinimide and 0.8g of dopamine in a round-bottom flask, add 12.0mL of dimethyl sulfoxide and 6.0mL of triethylamine mixed solvent, stir and react at 60°C for 24h, then slowly add 0.5g of 3-dimethylaminopropylamine, continue to react for 24h to obtain a brown viscous liquid, use acetone or anhydrous ethanol as a precipitant and stir vigorously until the product is no longer viscous, and obtain 1.24g of light brown powder PSI-DA-TA after drying.

[0088] The infrared spectrum of the polysuccinimide PSI-TA modified by dimethylaminopropylamine and dopamine is shown in Figure 3 From the infrared spectrum of PSI-PEA-TA, the infrared absorption peak originally belonging to the polysuccinimide ring structure disappeared, and obvious amide structure absorption peaks appeared at 1658 and 1538 cm-1, indicating that 3-dimethylaminopropylamine and dopamine were successfully introduced into the polysuccinimide polymer chain in the form of side groups after the ring-opening reaction. After NMR analysis ( Figure 4 ), indicating that the polysuccinimide has been completely ring-opened and amidated, and the grafting rate of different functional groups can be calculated to be 100.0% based on the integrated area of ​​the proton peak.

[0089] First, prepare a 10.0 mg / mL DMSO demulsification sample solution of PSI-DA-TA, and add the above demulsifier to 5.0 wt% O / W emulsion (the oil phase is crude oil, pH = 6, the oil content is 50.0 g / L, and the average size of the oil droplets is about 1.0-3.0 μm). When the demulsifier dosage reaches 5 mg / L, the oil removal rate is 99.9%, which is more efficient and faster than the single-grafted PSI-TA.

[0090] Example 3

[0091] The preparation method is as follows:

[0092] The preparation method of co-grafted PSI-DA-TA is as follows: weigh 0.98g of polysuccinimide and 0.9g of phenylethylamine in a round-bottom flask, add 12.0mL of dimethyl sulfoxide and 6.0mL of triethylamine mixed solvent, stir and react at 60°C for 24h, then slowly add 0.5g of 3-dimethylaminopropylamine, continue to react for 24h to obtain a brown viscous liquid, use acetone or anhydrous ethanol as a precipitant and stir vigorously until the product is no longer viscous, and obtain 1.36g of light brown powder PSI-PEA-TA after drying.

[0093] The infrared spectrum of polysuccinimide PSI-PEA-TA modified by stepwise co-modification of dimethylaminopropylamine and phenylethylamine is shown in Figure 3 From the infrared spectrum of PSI-PEA-TA, the infrared absorption peak originally belonging to the polysuccinimide ring structure disappeared, and obvious amide structure absorption peaks appeared at 1658 and 1538 cm-1, indicating that 3-dimethylaminopropylamine and dopamine were successfully introduced into the polysuccinimide polymer chain in the form of side groups after the ring-opening reaction. After NMR analysis ( Figure 4 ), indicating that the polysuccinimide has been completely ring-opened and amidated, and the grafting rate of different functional groups can be calculated to be 100.0% based on the integrated area of ​​the proton peak.

[0094] First prepare a 10.0 mg / mL PSI-DA-TA-2DMSO demulsification sample solution, and add the above demulsifier to a 5.0 wt% O / W emulsion (the oil phase is crude oil, pH = 6, the oil content is 50.0 g / L, and the average oil droplet size is about 1.0-3.0 μm). When the demulsifier dosage reaches 10 mg / L, the oil removal rate is close to 100%, which is more efficient and faster than the single-grafted PSI-TA co-grafted PSI-PEA-TA-2.

[0095] Example 4

[0096] The preparation method is as follows:

[0097] The preparation method of co-grafted PSI-DA-TA-1 is as follows: weigh 0.98g of polysuccinimide, 0.5g of 3-dimethylaminopropylamine and 0.9g of phenylethylamine in a round-bottom flask, add 12.0mL of dimethyl sulfoxide and 6.0mL of triethylamine mixed solvent, stir and react at 60°C for 24h to obtain a brown viscous liquid, use acetone or anhydrous ethanol as a precipitant and stir vigorously until the product is no longer viscous, and obtain 1.06g of light brown powder PSI-PEA-TA-1 after drying.

[0098] The infrared spectrum of the polysuccinimide PSI-PEA-TA-1 modified by one-step co-modification of dimethylaminopropylamine and phenylethylamine is shown in Figure 3From the infrared spectrum of PSI-PEA-TA-1, the infrared absorption peak originally belonging to the polysuccinimide ring structure disappeared, and obvious amide structure absorption peaks appeared at 1658 and 1538 cm-1, indicating that 3-dimethylaminopropylamine and dopamine were successfully introduced into the polysuccinimide polymer chain in the form of side groups after the ring-opening reaction. Figure 4 ), indicating that the polysuccinimide has been completely ring-opened and amidated, and the grafting rate of different functional groups can be calculated to be 100.0% based on the integrated area of ​​the proton peak.

[0099] First, prepare a 10.0 mg / mL DMSO demulsification sample solution, and add the above demulsifier to a 5.0 wt% O / W emulsion (the oil phase is crude oil, pH = 6, the oil content is 50.0 g / L, and the average oil droplet size is about 1.0-3.0 μm). When the demulsifier dosage reaches 10 mg / L, the oil removal rate is close to 100%. Compared with the single-grafted PSI-PEA-TA-2, the co-grafted PSI-PEA-TA-1 can achieve the same demulsification efficiency. The following PSI-PEA-TA representative demulsifier is synthesized in one step.

[0100] Example 5

[0101] Effect of emulsion pH on demulsification efficiency:

[0102] The demulsification effects of PSI-TA, PSI-DA-TA, and PSI-PEA-TA polymers at different pH conditions were investigated, however, at room temperature, they were unable to break the emulsions at pH values ​​of 2.0 and 11.0, respectively, whereas PSI-TA and PSI-PEA-TA were able to effectively destabilize the emulsions at pH values ​​of 4.0 and 9.0, e.g. Figure 7 As shown, the results show that the oil content in the demulsified water of PSI-TA demulsifier can reach 49.92 mg / L at a dosage of 70.0 mg / L at pH = 4.0, and the demulsification efficiency reaches 99.90%, while the oil content in the demulsified water of PSI-PEA-TA at a dosage of 20.0 mg / L can be reduced to 23.93 mg / L, and the demulsification efficiency reaches 99.95%. PSI-DA-TA has the demulsification ability. Under the condition of pH = 9.0, the demulsification efficiencies of PSI-TA, PSI-DA-TA and PSI-PEA-TA at a dosage of 30.0 mg / L reach 99.97%, 99.99% and 99.98% respectively, and the corresponding oil contents in the demulsified water are 14.86 mg / L, 4.71 mg / L and 10.86 mg / L respectively.

[0103] Example 6

[0104] Effect of emulsion oil content on demulsification efficiency:

[0105] The demulsification performance of emulsions with oil concentrations of 1.0-20.0wt% at pH 6.0 was evaluated. It was found that the optimal dosages of PSI-TA for treating emulsions with oil concentrations of 1.0 and 20.0wt% were 30.0mg / L and 50.0mg / L, respectively. The oil concentrations in the separated water were 54.44mg / L and 37.68mg / L, respectively. The demulsification efficiencies reached 99.46% and 99.98%, respectively. The optimal dosages of PSI-DA-TA for treating emulsions with oil concentrations of 1.0 and 30.0wt% were 5.0mg / L and 10.0mg / L, respectively. The oil concentrations in the separated water were 30. 47mg / L and 65.80mg / L, and the demulsification efficiency reached 99.70% and 99.98% respectively. The treatment of 30.0wt% O / W emulsion needs to be carried out at 40℃. The optimal dosage of PSI-PEA-TA for treating emulsions with oil concentrations of 1.0 and 30.0wt% is 10.0mg / L and 100.0mg / L. The oil concentrations in the separated water are 24.20mg / L and 10.70mg / L respectively, and the demulsification efficiency reaches 99.76% and 100.00% respectively. These results show that the above demulsifiers can effectively separate oily wastewater and O / W emulsions with high oil content.

[0106] Example 7

[0107] Evaluation of scale inhibition performance of modified polysuccinimide:

[0108] The scale inhibition ability of PSI-TA, PSI-DA-TA and PSI-PEA-TA was evaluated by static scale inhibition test. Figure 6 As shown, the scale inhibition efficiency of the sample for calcium sulfate is about 85.0% and remains almost unchanged as the dosage continues to increase.

[0109] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0110] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A bifunctional low-temperature demulsifier prepared by modification of polysuccinimide, characterized in that: The low-temperature demulsifier is an amphiphilic polysuccinimide derivative obtained by a one-step reaction of polysuccinimide and primary amine, the main chain of which is a strongly polar polyamide group, and the side chain (primary amine) can be designed and introduced according to the needs of the emulsion properties: a. Dimethylaminopropylamine-modified polysuccinimide (PSI-TA) prepared by single grafting of dimethylaminopropylamine b. Dimethylaminopropylamine dopamine co-modified polysuccinimide (PSI-DA-TA) c. Dimethylaminopropylamine phenylethylamine step-grafted polysuccinimide (PSI-PEA-TA-2) d. One-step co-modification of polysuccinimide with dimethylaminopropylamine and phenylethylamine (PSI-PEA-TA) 2. The bifunctional low-temperature demulsifier prepared by modification of polysuccinimide according to claim 1, characterized in that: The grafting rate of the primary amine is 50% to 100%, and the grafting reaction is one-step or two-step to achieve the preparation of the target product.

3. The bifunctional low-temperature demulsifier prepared by modification of polysuccinimide according to claim 1, characterized in that: The infrared spectrum of the polysuccinimide-modified derivative shows obvious amide structure absorption peaks, and the nuclear magnetic hydrogen spectrum shows obvious amide characteristic chemical shifts of the side chain.

4. The bifunctional low-temperature demulsifier prepared by modification of polysuccinimide according to claim 1, characterized in that: The modified monomer is one of primary amine, 3-dimethylaminopropylamine, dopamine hydrochloride and β-phenylethylamine, or a combination of aliphatic primary amine and aromatic primary amine. The molecular weight of the polysuccinimide is not less than 7000-8000, and the purity is industrial grade or above.

5. According to claim 1, a bifunctional low-temperature demulsifier prepared by modifying polysuccinimide, a method for preparing a dimethylaminopropylamine modified polysuccinimide demulsifier is provided, characterized in that: The following steps are involved: Step 1: dissolving polysuccinimide in dimethyl sulfoxide (DMSO) at a mass ratio of polysuccinimide to DMSO of 1:(10-15), and stirring thoroughly under nitrogen until completely dissolved; Step 2: Weigh a certain amount of dimethylaminopropylamine into the obtained polysuccinimide solution, so that the ratio of its amount to polysuccinimide is maintained in the range of nPSI:nTA=1:50-100, and stir it thoroughly to dissolve it to obtain a mixed solution; Step 3: Heat the mixed solution in step 2 to 40-50°C and stir for 6-30h to obtain a brown viscous liquid; Step 4: Use a precipitant to precipitate and separate the reaction solution in step 3, wash and dry the filter residue to obtain the polysuccinimide modified low-temperature demulsifier, and the mass ratio of the precipitant to the reaction solution is (1-5):

1.

6. According to claim 1, a bifunctional low-temperature demulsifier prepared by modifying polysuccinimide, a method for preparing a polysuccinimide demulsifier prepared by co-modifying polysuccinimide with dimethylaminopropylamine and dopamine and grafting polysuccinimide with dimethylaminopropylamine and phenethylamine in steps is provided, characterized in that: The following steps are involved: Step 1: dissolving polysuccinimide in dimethyl sulfoxide (DMSO) at a mass ratio of polysuccinimide to DMSO of 1:(10-15), and stirring thoroughly under nitrogen until completely dissolved; Step 2: The obtained polysuccinimide solution is weighed with a certain amount of dopamine and phenylethylamine, so that the ratio of the primary amine to the polysuccinimide substance is maintained in the range of nPSI:nTA=1:20-80, and is fully stirred to dissolve, thereby obtaining a mixed solution; Step 3: Heat the mixed solution in step 2 to 40-50° C. and stir for 12-30 hours, add dimethylaminopropylamine so that the ratio of dimethylaminopropylamine to dopamine or phenylethylamine is maintained at nTA:nDA / PEA=2-8, and continue to stir sufficiently to obtain a brown viscous liquid; Step 4: Use a precipitant to precipitate and separate the reaction solution in step 3, wash and dry the filter residue to obtain the polysuccinimide modified low-temperature demulsifier, and the mass ratio of the precipitant to the reaction solution is (1-5):

1.

7. According to claim 1, a bifunctional low-temperature demulsifier prepared by modifying polysuccinimide, a method for preparing a polysuccinimide demulsifier modified by dimethylaminopropylamine and phenethylamine in one step is provided, characterized in that: The following steps are involved: Step 1: dissolving polysuccinimide in dimethyl sulfoxide (DMSO) at a mass ratio of polysuccinimide to DMSO of 1:(10-15), and stirring thoroughly under nitrogen until completely dissolved; Step 2: The obtained polysuccinimide solution is weighed with a certain amount of dimethylaminopropylamine and phenylethylamine, so that the ratio of the primary amine to the polysuccinimide substance is maintained in the range of nPSI:nTA=1:50-100, and the ratio of the dimethylaminopropylamine to the phenylethylamine substance is maintained in the range of nTA:nPEA=1:0-0.8, and the mixture is stirred sufficiently to dissolve, thereby obtaining a mixed solution; Step 3: Heat the mixed solution in step 2 to 40-50°C and stir for 6-30h to obtain a brown viscous liquid; Step 4: Use a precipitant to precipitate and separate the reaction solution in step 3, wash and dry the filter residue to obtain the polysuccinimide modified low-temperature demulsifier, and the mass ratio of the precipitant to the reaction solution is (1-5):

1.

8. A method for preparing a bifunctional low-temperature demulsifier by modifying polysuccinimide according to any one of claims 5 to 7, characterized in that: The solid sample is obtained by vacuum drying or freeze drying at 50°C.

9. The bifunctional low-temperature demulsifier prepared by modification of polysuccinimide according to claim 1, characterized in that: The main chain is a highly polar polyamide skeleton, and the grafted side chain is a hydrophobic alkyl chain or contains an alkyl chain and an aromatic ring at the same time, which has excellent interfacial activity. The flocculation and aggregation ability of the demulsifier can be regulated by regulating the length of the alkyl primary amine. The demulsifier is degradable and can effectively inhibit the scaling of calcium and magnesium ions. It is not only an excellent O / W type demulsifier but also has scale inhibition ability.

10. Use of a bifunctional low-temperature demulsifier prepared by modifying polysuccinimide according to any one of claims 1 to 9 in the fields of crude oil demulsifier and emulsified oily wastewater treatment.

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