A polyether-grafted polymer water-repellent agent and its preparation method

Abstract

This invention discloses a polyether-grafted polymer water-cleaning agent and its preparation method, relating to the field of oilfield chemical technology. The preparation method includes the following steps: dissolving N-(3-dimethylaminopropyl)methacrylamide in ethanol to obtain a monomer solution, purging with nitrogen for 15 min, adding an initiator to polymerize and obtain a polymer solution of poly(3-dimethylaminopropyl)methacrylamide, adding p-chlorobenzaldehyde to the polymer solution, purging with nitrogen for 5 min, reacting to obtain a modified poly(3-dimethylaminopropyl)methacrylamide solution, and continuing to add polyether monoamine to the modified poly(3-dimethylaminopropyl)methacrylamide solution, stirring at room temperature for 10-14 h to obtain the final product. The polyether-grafted polymer water-cleaning agent disclosed in this invention has good water-cleaning and oil-removing performance for produced water in heavy oil fields. This water-cleaning agent can be used in inclined plate oil separators for flocculation and oil removal, and can also be used as a flotation agent in flotation oil separators for air flotation oil removal, with a wide range of applications.

Description

Technical Field

[0001] This invention relates to the field of oilfield chemical technology, specifically to a polyether-grafted polymer water-repellent agent and its preparation method. Background Technology

[0002] As offshore oilfields enter the mid-to-late stages of water injection production, the water content in the produced fluid increases significantly, leading to a corresponding increase in the volume of produced water (typically oily wastewater). This poses a significant challenge to normal production in offshore oilfields. Due to limited space on offshore platforms, expanding or increasing the capacity of produced water treatment equipment is extremely difficult. This results in a significant reduction in the residence time of oily wastewater in existing treatment equipment, thus placing higher demands on the performance of treatment agents. Currently, the process for treating produced water on offshore platforms typically involves a three-stage process: inclined plate separator, air flotation, and walnut shell filtration. Cleaning agents and air flotation agents are added to the inclined plate separator and air flotation unit, respectively. Floating oil and large dispersed oil droplets in the produced water can be removed in the inclined plate separator, while small emulsified oil droplets are usually removed in the air flotation unit. However, existing cleaning agents only have flocculation capabilities and can only be used in the inclined plate separator, not as flotation agents in the flotation unit. To remove small emulsified oil droplets more efficiently and quickly, more efficient cleaning agents and flotation agents need to be developed. Summary of the Invention

[0003] In view of this, the present invention proposes a polyether-grafted polymer water purifier and its preparation method. The prepared water purifier has both flocculation and flotation functions. It can be used as a flocculant in an inclined plate oil separator and as a flotation agent in a flotation cell, and has a wide range of applications.

[0004] This invention discloses a polyether-grafted polymer water-repellent agent and its preparation method, comprising the following steps:

[0005] Step S1: Dissolve N-(3-dimethylaminopropyl)methacrylamide in ethanol to obtain a monomer solution. After purging with nitrogen for 15 min, add an initiator to react and obtain a polymer solution of poly(3-dimethylaminopropyl)methacrylamide.

[0006] Step S2: Add p-chlorobenzaldehyde to the polymer solution, and react with nitrogen for 5 min to obtain a modified poly(3-dimethylaminopropyl)methacrylamide solution;

[0007] Step S3: Continue to add polyether monoamine to the modified poly-N-(3-dimethylaminopropyl)methacrylamide solution, and stir the reaction at room temperature for 10-14 hours to obtain the final product.

[0008] In one embodiment of the present invention, the monomer concentration in the monomer solution in step S1 is 15-20% by mass concentration.

[0009] In one embodiment of the present invention, the initiator in step S1 is azobisisobutyronitrile, and the amount of initiator added is 0.1 to 0.3% of the mass of N-(3-dimethylaminopropyl)methacrylamide.

[0010] One embodiment of the present invention is that the polymerization reaction in step S1 is carried out at 50-65°C for 8-12 hours.

[0011] In one embodiment of the present invention, the ratio of N-(3-dimethylaminopropyl)methacrylamide in step S1 to p-chlorobenzaldehyde in step S2 is 1:0.2 to 0.5, based on a molar ratio.

[0012] In one embodiment of the present invention, the reaction conditions in step S2 are: reaction at 70-80°C for 20 hours.

[0013] In one embodiment of the present invention, the polyether monoamine in step S3 is one of M-1000, M-2005, M-2070, and M3085.

[0014] In one embodiment of the present invention, the ratio of p-chlorobenzaldehyde in step S2 to polyether monoamine in step S3 is 1:0.05 to 0.2, based on a molar ratio.

[0015] One embodiment of the present invention is a polyether-grafted polymer water-repellent prepared by the above method.

[0016] The technical effects of this invention are as follows:

[0017] The polyether-grafted polymer water cleaning agent disclosed in this invention has excellent water cleaning and oil removal performance for produced water from heavy oil fields. At the same time, this water cleaning agent can be used in flocculation oil removal in inclined plate oil separators, and can also be used as a flotation agent in air flotation oil removal in flotation oil separators, with a wide range of applications. Attached Figure Description

[0018] Figure 1 The infrared spectrum of the polyether-grafted polymer water-repellent agent in Example 1 of this invention is shown. Detailed Implementation

[0019] The present invention will be further described in detail below with reference to the embodiments. However, the implementation of the present invention is not limited thereto. Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods, and the materials and reagents used are commercially available unless otherwise specified.

[0020] Example 1

[0021] (1) Add 20g of N-(3-dimethylaminopropyl)methacrylamide and 80g of ethanol to a 250mL screw bottle, stir magnetically to dissolve, and then purge with nitrogen to remove oxygen for 15min; then add 0.03g of azobisisobutyronitrile, and react with magnetic stirring at 55℃ for 10h to obtain poly(N-(3-dimethylaminopropyl)methacrylamide).

[0022] (2) Add 4.96 g of p-chlorobenzaldehyde to the obtained poly(N-(3-dimethylaminopropyl)methacrylamide) solution, purge with nitrogen for 5 min, and then heat to 80 °C and react for 20 h to obtain modified poly(N-(3-dimethylaminopropyl)methacrylamide) with benzaldehyde as the side group.

[0023] (3) Add 7.06g of polyether monoamine M-2005 to the modified poly(3-dimethylaminopropyl)methacrylamide solution and stir at room temperature for 12h to obtain polyether grafted polymer water-repellent agent.

[0024] Example 2

[0025] The implementation method of this embodiment is basically the same as that of Example 1. The difference is that in step (1), the amount of N-(3-dimethylaminopropyl)methacrylamide is 15g, the amount of ethanol is 85g, the amount of azobisisobutyronitrile is 0.0225g, in step (2) the amount of p-chlorobenzaldehyde is 3.72g, and in step (3) the amount of polyether monoamine M-2005 is 5.295g.

[0026] Example 3

[0027] The implementation method of this embodiment is basically the same as that of Example 1, except that the amount of azobisisobutyronitrile used in step (1) is 0.02g.

[0028] Example 4

[0029] The implementation method of this embodiment is basically the same as that of Example 1, except that the amount of azobisisobutyronitrile used in step (1) is 0.04g.

[0030] Example 5

[0031] The implementation method of this embodiment is basically the same as that of embodiment 1, except that the amount of azobisisobutyronitrile used in step (1) is 0.06g.

[0032] Example 6

[0033] The implementation method of this embodiment is basically the same as that of embodiment 1, except that the reaction temperature in step (1) is 50°C.

[0034] Example 7

[0035] The implementation method of this embodiment is basically the same as that of embodiment 1, except that the reaction temperature in step (1) is 60°C.

[0036] Example 8

[0037] The implementation method of this embodiment is basically the same as that of embodiment 1, except that the reaction temperature in step (1) is 65°C.

[0038] Example 9

[0039] The implementation method of this embodiment is basically the same as that of embodiment 1, except that the amount of p-chlorobenzaldehyde used in step (2) is 3.31g and the amount of polyether monoamine M-2005 used in step (3) is 4.70g.

[0040] Example 10

[0041] The implementation method of this embodiment is basically the same as that of embodiment 1, except that the amount of p-chlorobenzaldehyde used in step (2) is 6.62g and the amount of polyether monoamine M-2005 used in step (3) is 9.4g.

[0042] Example 11

[0043] The implementation method of this embodiment is basically the same as that of embodiment 1, except that the amount of p-chlorobenzaldehyde used in step (2) is 8.275g and the amount of polyether monoamine M-2005 used in step (3) is 11.75g.

[0044] Example 12

[0045] The implementation method of this embodiment is basically the same as that of Example 1, except that the polyether monoamine in step (3) is M-1000 and the amount is 3.53g.

[0046] Example 13

[0047] The implementation method of this embodiment is basically the same as that of Example 1, except that the polyether monoamine in step (3) is M-2070 and the amount is 7.06g.

[0048] Example 14

[0049] The implementation method of this embodiment is basically the same as that of Example 1, except that the polyether monoamine in step (3) is M-3085 and the amount is 10.59g.

[0050] Example 15

[0051] The implementation method of this embodiment is basically the same as that of Example 1, except that the amount of polyether monoamine M-2005 used in step (3) is 3.53g.

[0052] Example 16

[0053] The implementation method of this embodiment is basically the same as that of Example 1, except that the amount of polyether monoamine M-2005 used in step (3) is 5.295g.

[0054] Example 17

[0055] The implementation method of this embodiment is basically the same as that of Example 1, except that the amount of polyether monoamine M-2005 used in step (3) is 10.59g.

[0056] Example 18

[0057] The implementation method of this embodiment is basically the same as that of Example 1, except that the amount of polyether monoamine M-2005 used in step (3) is 14.12g.

[0058] Comparative Example 1

[0059] The implementation method of this embodiment is basically the same as that of Example 1. The difference is that in step (1), the amount of N-(3-dimethylaminopropyl)methacrylamide is 10g, the amount of ethanol is 90g, the amount of azobisisobutyronitrile is 0.015g, in step (2) the amount of p-chlorobenzaldehyde is 2.48g, and in step (3) the amount of polyether monoamine M-2005 is 3.53g.

[0060] Comparative Example 2

[0061] The implementation method of this embodiment is basically the same as that of Example 1. The difference is that in step (1), the amount of N-(3-dimethylaminopropyl)methacrylamide is 25g, the amount of ethanol is 75g, the amount of azobisisobutyronitrile is 0.0375g, in step (2) the amount of p-chlorobenzaldehyde is 6.2g, and in step (3) the amount of polyether monoamine M-2005 is 8.825g.

[0062] Comparative Example 3

[0063] The implementation method of this embodiment is basically the same as that of Example 1, except that the amount of azobisisobutyronitrile used in step (1) is 0.08g.

[0064] Comparative Example 4

[0065] The implementation method of this embodiment is basically the same as that of embodiment 1, except that the reaction temperature in step (1) is 70°C.

[0066] To better illustrate the technical effects of the present invention, the following provides corresponding characterization and performance evaluation of the relevant embodiments.

[0067] I. Infrared Characterization

[0068] The polyether-grafted polymer water-repellent agent prepared in Example 1 was characterized by infrared spectroscopy, and the results are as follows: Figure 1As shown. By Figure 1 As can be seen, 3358cm -1 and 1664cm -1 The characteristic absorption peak of the amide group (from N-(3-dimethylaminopropyl)methacryloyl) is 3023 cm⁻¹. -1 and 1531cm -1 The characteristic absorption peak of the benzene ring (from p-chlorobenzaldehyde) is 1100 cm⁻¹. -1 The characteristic absorption peak for the ether bond (originating from polyether monoamine) indicates that the infrared characterization results confirm that the structure of the polyether-grafted polymer water-repellent agent conforms to expectations.

[0069] II. Performance Evaluation

[0070] The treatment performance of the water purification agent mainly includes two aspects: flocculation performance and flotation performance. The following evaluation of these two aspects will illustrate the effect of the polyether grafted polymer water purification agent in this invention.

[0071] (1) Effect of monomer concentration on the flocculation performance of polyether grafted polymer water-purifying agents

[0072] The flocculation performance evaluation experiment method is as follows: 80 mL of oilfield produced water (oil content 5500 mg / L) is added to a dehydration bottle, kept at 60℃ for 10 min, then 200 ppm of reagent is added, shaken by hand 50 times, and allowed to stand for 5 min. A sample of the lower layer is taken to determine the oil content, and the oil removal rate is calculated. Examples 1 and 2 and Comparative Examples 1 and 2 are evaluated according to the above method, and the results are shown in Table 1.

[0073] Table 1. Effect of monomer concentration on the flocculation performance of polyether grafted polymer water-clearing agents.

[0074] Group Example 1 Example 2 Comparative Example 1 Comparative Example 2 Monomer concentration (%) 20 15 10 25 Final product liquidity good good good Difference Oil removal rate (%) 96.5 95.5 72.8 ---

[0075] As shown in Table 1, when the monomer concentration is low (10%), the product has a low oil removal rate and poor flocculation performance; when the monomer concentration is high (25%), the product has poor flowability and is not practical; while when the monomer concentration is between 15% and 20%, the product has good flocculation performance and good flowability.

[0076] (2) Effect of initiator dosage on the flocculation performance of polyether grafted polymer water-purifying agent

[0077] The flocculation performance evaluation experiments were conducted on Examples 1, 3-5, and Comparative Example 3, and the results are shown in Table 2:

[0078] Table 2. Effect of initiator concentration on the flocculation performance of polyether grafted polymer water-clearing agents.

[0079] Group Example 1 Example 3 Example 4 Example 5 Comparative Example 3 Initiator dosage (%) 0.15 0.1 0.2 0.3 0.4 Oil removal rate (%) 96.5 93.6 96.0 96.0 83.2

[0080] As shown in Table 2, when the initiator dosage is in the range of 0.1% to 0.3%, the final product has good flocculation performance and the oil removal rate can reach more than 96%. However, when the initiator dosage is 0.4%, the oil removal rate of the product decreases significantly. This may be because when the initiator dosage is too high, the molecular weight of the product decreases and the flocculation bridging performance decreases, thus the oil removal rate decreases.

[0081] (3) Effect of reaction temperature on the flocculation performance of polyether grafted polymer water-clearing agent

[0082] The flocculation performance evaluation experiments were conducted on Examples 1, 6-8, and Comparative Example 4, and the results are shown in Table 3:

[0083] Table 3. Effect of reaction temperature on the flocculation performance of polyether grafted polymer water-clearing agents.

[0084] Group Example 1 Example 6 Example 7 Example 8 Comparative Example 4 Reaction temperature (°C) 55 50 60 65 70 Oil removal rate (%) 96.5 95.0 95.0 93.2 87.2

[0085] As shown in Table 3, when the reaction temperature is in the range of 50 to 65℃, the final product has good flocculation performance. However, when the reaction temperature is 70℃, the oil removal rate of the product decreases significantly. This may also be because when the temperature is too high, the molecular weight of the product decreases, the flocculation bridging performance decreases, and thus the oil removal rate decreases.

[0086] (4) Effect of p-chlorobenzaldehyde dosage on the flocculation performance of polyether grafted polymer water clearing agent

[0087] The flocculation performance evaluation experiments of Examples 1 and 9-11 were conducted, and the results are shown in Table 4:

[0088] Table 4. Effects of p-chlorobenzaldehyde dosage on the flocculation performance of polyether grafted polymer water-clearing agents.

[0089]

[0090] Table 4 shows that as the molar ratio of p-chlorobenzaldehyde to N-(3-dimethylaminopropyl)methacrylamide increases, the oil removal effect initially increases and then decreases. Increasing the p-chlorobenzaldehyde content leads to a greater amount of block polyether in the final product. Block polyethers possess interfacial activity, and their content within a suitable range is beneficial for adsorption on the surfaces of multiple oil droplets (oil-water interface) in the final product, thus bridging and flocculating. However, excessively high content results in a final product with strong emulsifying properties, which is detrimental to flocculation and oil removal. Therefore, the appropriate molar ratio of p-chlorobenzaldehyde to N-(3-dimethylaminopropyl)methacrylamide should be in the range of 0.2:1 to 0.5:1.

[0091] (5) Effect of polyether monoamine type on the flocculation and flotation performance of polyether grafted polymer water purification agent

[0092] Flocculation performance evaluation experiments and flotation performance evaluation experiments were conducted on Examples 1 and 12-14, respectively. The cationic polymer flocculant FO4240 (purchased from Essen, France) was used as a control and evaluated together with it. The flotation performance evaluation method was as follows: 400 mL of oilfield produced water (oil content 520 mg / L) was added to a flotation column, along with 25 mg / L of the reagent. Flotation was carried out for 2 minutes at 20°C and an air flow rate of 1 L / min. The results are shown in Table 5.

[0093] Table 5. Effects of Polyether Monoamine Type on the Flocculation and Flotation Performance of Polyether Grafted Polymer Water Purifiers

[0094] Group Example 1 Example 12 Example 13 Example 14 FO4240 Polyether monoamine M-2005 M-1000 M-2070 M-3085 FO4240 Oil removal rate (%) in flocculation experiment 96.5 93.0 96.5 96.5 95.5 Oil removal rate (%) in flotation experiment 97.0 91.0 96.5 94.0 35.0

[0095] As shown in Table 5, the four types of polyether monoamines all exhibit good flocculation and flotation performance of the polyether grafted polymer water purifier, and all demonstrate good oil removal effects. In contrast, the cationic polymer flocculant FO4240 only exhibits good flocculation performance and does not possess flotation properties, proving that the polyether grafted polymer water purifier disclosed in this invention possesses both good flocculation and good flotation performance.

[0096] (6) Effect of the molar ratio of polyether monoamine to chlorobenzaldehyde on the flocculation and flotation performance of polyether grafted polymer water purification agents

[0097] Flocculation performance evaluation experiments and flotation performance evaluation experiments were conducted on Examples 1 and 15-18, respectively, and the results are shown in Table 6:

[0098] Table 6. Effects of the molar ratio of polyether monoamine to chlorobenzaldehyde on the flocculation and flotation performance of polyether grafted polymer water purification agents.

[0099] Group Example 1 Example 15 Example 16 Example 17 Example 18 molar ratio of polyether monoamine to chlorobenzaldehyde 0.1:1 0.05:1 0.075:1 0.15:1 0.2:1 Oil removal rate (%) in flocculation experiment 96.5 90.5 93.5 93.1 90.0 Oil removal rate (%) in flotation experiment 97.0 92.1 95.0 97.0 95.5

[0100] As shown in Table 6, with the increase of the molar ratio of polyether monoamine to chlorobenzaldehyde, the flocculation oil removal rate and flotation oil removal rate of the final product first increase and then decrease. When the molar ratio of the two is in the range of 0.05:1 to 0.2:1, the final product has both good flocculation performance and flotation performance.

[0101] In summary, this invention prepares a water cleaning agent that combines good flocculation and flotation properties. It has excellent water cleaning and oil removal performance for produced water from heavy oil fields. It can be used for flocculation oil removal in inclined plate oil separators, or as a flotation agent in air flotation oil removal in flotation oil separators, and has a wide range of applications.

[0102] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the embodiments of the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for preparing a polyether grafted polymer water reducer, characterized by, The method comprises the following steps: Step S1: dissolving N-(3-dimethylaminopropyl) methacrylamide in ethanol to obtain a monomer solution, and then adding an initiator to initiate a polymerization reaction after nitrogen is passed for 15 min to obtain a polymer solution of poly-N-(3-dimethylaminopropyl) methacrylamide; Step S2: adding p-chlorobenzaldehyde to the polymer solution, and then reacting after nitrogen is passed for 5 min to obtain a modified poly-N-(3-dimethylaminopropyl) methacrylamide solution; Step S3: continuously adding a polyether monoamine to the modified poly-N-(3-dimethylaminopropyl) methacrylamide solution, and then stirring and reacting at room temperature for 10-14 h to obtain the product; In step S1, the monomer concentration in the monomer solution is 15-20% by mass; In step S1, the initiator is azobisisobutyronitrile, and the amount of the initiator is 0.1-0.3% of the mass of N-(3-dimethylaminopropyl) methacrylamide; In step S1, the polymerization reaction is performed at 50-65 ℃ for 8-12 h; In step S1, the ratio of N-(3-dimethylaminopropyl) methacrylamide to p-chlorobenzaldehyde in step S2 is 1:0.2-0.5 by mole ratio; In step S3, the polyether monoamine is one of M-1000, M-2005, M-2070 and M3085; In step S2, the ratio of p-chlorobenzaldehyde to the polyether monoamine in step S3 is 1:0.05-0.2 by mole ratio.

2. The method for preparing a polyether-grafted polymer water-repellent agent according to claim 1, characterized in that: In step S2, the reaction is performed at 70-80 ℃ for 20 h.

3. A polyether grafted polymer clear water agent characterized by, The product is prepared by the method of any one of claims 1-2.

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