Cationic polymer containing functional acrylamide as well as preparation method and application of cationic polymer

Abstract

The invention belongs to the technical field of oilfield exploitation, and relates to a cationic polymer containing functional acrylamide and a preparation method and application thereof. The cationic polymer comprises a structural unit derived from a cationic unsaturated monomer, a structural unit derived from an acrylamide monomer, a structural unit derived from an alkenyl amide monomer containing an aromatic ring structure and a structural unit derived from an alkyl alkenyl amide monomer. Compared with the prior art, the cationic polymer containing the functional group acrylamide has the following beneficial effects that the dehydration speed and the water purification effect of a water treatment agent are improved, the cationic polymer has a very good treatment effect on oily sewage, the content of solid suspended matters and oil in the treated produced water is low, and the requirements of oilfield reinjection or discharge are met; the water treatment agent provided by the invention can be independently used, and can also be compounded with other existing water treatment agents for use according to the property of produced liquid oil-in-water emulsion, so that the universality of the water treatment agent is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of oilfield exploitation, and particularly relates to a cationic polymer containing functional acrylamide, a preparation method thereof, and an application thereof. Background Art

[0002] As most domestic oilfields enter the middle and late stages of development, the water cut of produced fluids increases year by year, and a large amount of oily sewage needs to be treated urgently; at the same time, the widespread use of various stimulation measures and the large-scale development of unconventional oilfields such as heavy oil and low permeability have led to the very complex nature of oilfield produced water, which is characterized by high viscosity, strong emulsification stability of oil droplets and suspended solids in water, etc., increasing the difficulty of oil-water separation, and the problem of treating oil-in-water (O / W) emulsions is becoming increasingly serious.

[0003] To treat oily sewage, water treatment agents must be added to demulsify it to achieve the purpose of removing oil. Currently, the commonly used water treatment agents are mostly low-molecular electrolytes, alcohols, surfactants, polymers, and the compounding of various systems, etc., which can no longer meet the increasingly complex situation of oilfield water treatment and the strict environmental protection reinjection requirements. After treatment, the oil content and suspended solids are still likely to exceed the standard, affecting the next step of discharge and reinjection, etc. Therefore, there is an urgent need to develop a new type of high-efficiency water treatment agent to ensure the continuous and stable production of oilfields.

[0004] Cationic water treatment agents are the main type of water treatment agents for treating oily sewage at present. The interface of the produced water O / W emulsion generally has a negative charge. Cationic groups can neutralize the negative charge at the oil-water interface, compress and destroy the double electric layer, reduce the electrostatic repulsion between oil droplets, bridge the oil beads, and enhance the coalescence ability of oil droplets, so as to achieve the purpose of demulsifying and removing oil. By methods such as graft copolymerization modification, the demulsifying and oil-removing effect can be improved to adapt to the increasing complexity of oilfield produced water.

[0005] As many oilfields in China enter the secondary oil recovery and tertiary oil recovery stages, the widespread use of water flooding for injection and the extensive application of enhanced oil recovery technologies such as chemical flooding and steam flooding, and the implementation of various stimulation measures such as acidification, fracturing, profile control, and water plugging, the proportion of oil-in-water (O / W) emulsions in oilfield produced fluids is increasing, the emulsification degree of O / W emulsions is more serious, and the emulsions are becoming more and more stable, and the treatment difficulty is increasing. When using existing cationic polymers as demulsifiers, the oil removal rate and the removal rate of solid suspended particles still need to be improved. Therefore, it is necessary to further improve the demulsifying and oil-removing effect of oilfield sewage. Summary of the Invention

[0006] The object of the present invention is to overcome the above-mentioned defects in the prior art, and to provide a cationic polymer containing functional acrylamide, a preparation method and an application thereof. By graft copolymerization, acrylamide containing an aromatic ring structure and alkyl acrylamide are introduced into the molecular chain segment of the cationic copolymer, which can interact with hydrophobic oil droplets in oily sewage, improve the interfacial adsorption and sweeping coalescence performance, quickly adsorb the oil phase in the sewage, and improve the oil removal rate. The diacetone acrylamide copolymer has the function of clarifying suspended solids in water, and the dewatered water is clear, with low suspended solid particles and oil content. The obtained cationic polymer has good demulsification and oil removal effects on crude oil sewage, and can remove suspended solid particles to purify water.

[0007] To achieve the object of the present invention, in a first aspect of the present invention, there is provided a cationic polymer containing functional acrylamide, the cationic polymer comprising a structural unit derived from a cationic unsaturated monomer, a structural unit derived from an acrylamide monomer, a structural unit derived from an alkenylamide monomer containing an aromatic ring structure, and a structural unit derived from an alkyl alkenylamide monomer.

[0008] In a second aspect of the present invention, there is provided a preparation method of a cationic polymer containing functional acrylamide, comprising the following steps:

[0009] In the presence of an initiator, a cationic unsaturated monomer, an acrylamide monomer containing an aromatic ring structure, an alkyl acrylamide monomer and an acrylamide monomer are subjected to a contact reaction to obtain the cationic polymer.

[0010] In a third aspect of the present invention, there is provided an application of the cationic polymer containing functional acrylamide prepared by the preparation method in the preparation of an oilfield produced water treatment agent.

[0011] The present invention has the following beneficial effects:

[0012] (1) The cationic polymer containing functional group acrylamide provided by the present invention improves the dehydration speed and water purification effect of the water treatment agent, has a very good treatment effect on oily sewage, and the produced water after treatment has low solid suspended matter and oil content, meeting the requirements of oilfield reinjection or discharge.

[0013] (2) The present invention preferably adopts the emulsion polymerization method, without adding toxic and harmful solvents, without generating three wastes, with low environmental protection energy consumption, and the production process is safe, mild and easy to operate.

[0014] (3) The water treatment agent provided by the present invention can be used alone or can be compounded with other existing water treatment agents according to the properties of the water-in-oil emulsion of the produced liquid, improving the universality of the water treatment agent.

[0015] Other features and advantages of the present invention will be described in detail in the following specific embodiments. Specific Embodiments

[0016] The following is a detailed description of the specific embodiments of the present invention. It should be understood that the specific embodiments described herein are only for the purpose of illustrating and explaining the present invention, and are not intended to limit the present invention.

[0017] To achieve the object of the present invention, a first aspect of the present invention provides a cationic polymer containing a functional acrylamide, the cationic polymer comprising structural units derived from cationic unsaturated monomers, structural units derived from acrylamide monomers, structural units derived from alkenylamide monomers containing an aromatic ring structure, and structural units derived from alkylalkenylamide monomers.

[0018] In the present invention, acrylamide containing an aromatic ring structure and alkylacrylamide can interact with hydrophobic oil droplets in oily sewage, improve the interfacial adsorption and sweeping coalescence performance, and improve the oil removal rate, while the diacetone acrylamide copolymer has the characteristics of clarifying suspended solids, clear dewatered water, low suspended solid particles and oil content.

[0019] According to the present invention, preferably, based on the total amount of the structural units of the polymer, the content of the structural units derived from cationic unsaturated monomers is 40-90 wt%, preferably 60-85 wt%, the content of the structural units derived from acrylamide monomers is 1-40 wt%, preferably 5-25 wt%, the content of the structural units derived from alkenylamide monomers containing an aromatic ring structure is 2-15 wt%, preferably 5-11 wt%, and the content of the structural units derived from alkylalkenylamide monomers is 5-30 wt%, preferably 5-25 wt%.

[0020] According to the present invention, preferably, the structural formulas of the cationic unsaturated monomers, acrylamide monomers, alkenylamide monomers containing an aromatic ring structure, and alkylalkenylamide monomers are as follows:

[0021]

[0022] Among them, A is a cationic unsaturated monomer, B is an acrylamide monomer, C is an alkenylamide monomer containing an aromatic ring structure, and D is an alkylalkenylamide monomer;

[0023] In the formula, R1, R2, R4, and R6 are each independently H or an alkyl group having 1 to 5 carbon atoms, R3 is an alkylene group having 1 to 5 carbon atoms, R5 is an alkyl group having 1 to 18 carbon atoms, preferably an alkyl group having 12 to 18 carbon atoms, and X is a halogen, preferably Cl or Br.

[0024] According to the present invention, preferably, the structural formula of the cationic polymer is as follows:

[0025]

[0026] In the formula, a, b, c, d, and e represent the number of repeating units, and a, b, c, d, and e are all non-zero natural numbers.

[0027] In the present invention, a, b, c, d, and e are between 10 and 10,000, and the number-average molecular weight of the cationic polymer is between 100,000 and 3,000,000.

[0028] According to the present invention, preferably, the cationic unsaturated monomer is (meth)acryloyloxyethyl trimethyl ammonium chloride;

[0029] According to the present invention, preferably, the acrylamide monomer is diacetone acrylamide.

[0030] According to the present invention, preferably, the alkenyl amide monomer containing an aromatic ring structure is benzyl acrylamide.

[0031] According to the present invention, preferably, the alkyl alkenyl amide monomer is at least one of dodecyl acrylamide, hexadecyl acrylamide, and octadecyl acrylamide.

[0032] The second aspect of the present invention provides a method for preparing a cationic polymer containing a functional acrylamide, including the following steps:

[0033] In the presence of an initiator, the cationic unsaturated monomer, the alkenyl amide monomer containing an aromatic ring structure, the alkyl acrylamide monomer, and the acrylamide monomer are subjected to a contact reaction to obtain the cationic polymer.

[0034] According to the present invention, preferably, based on the total weight of the reaction monomers, the addition amount of the cationic unsaturated monomer is 40-90 wt%, preferably 60-85 wt%, the addition amount of the acrylamide monomer is 1-40 wt%, preferably 5-25 wt%, the addition amount of the alkenyl amide monomer containing an aromatic ring structure is 2-15 wt%, preferably 5-11 wt%, and the addition amount of the alkyl alkenyl amide monomer is 5-30 wt%, preferably 5-25 wt%.

[0035] According to the present invention, preferably, it includes the following steps:

[0036] (1) Under the protection of an inert gas, the cationic unsaturated monomer, the alkenyl amide monomer containing an aromatic ring structure, and the alkyl acrylamide monomer are mixed, heated to the polymerization temperature, and the first part of the initiator is added dropwise for reaction;

[0037] (2) The acrylamide monomer and the second part of the initiator are added dropwise to the reaction system in step (1), and the reaction is continued to obtain the cationic polymer.

[0038] According to the present invention, preferably, emulsion polymerization is adopted, and step (1) includes:

[0039] (a) Dissolve the emulsifier in a solvent, add a cationic unsaturated monomer, an acrylamide monomer containing an aromatic ring structure, and an alkylacrylamide monomer, and emulsify to obtain an emulsion;

[0040] (b) Under the protection of an inert gas, heat the emulsion obtained in step (a) to the polymerization temperature, and dropwise add the first part of the initiator for reaction.

[0041] In the present invention, the cationic unsaturated monomer, the acrylamide containing an aromatic ring structure, the alkylacrylamide monomer, and the diacetone acrylamide monomer are polymerized by emulsion polymerization to introduce an aromatic ring structure and a hydrophobic functional group into the molecular chain segment, which can rapidly adsorb the oil phase in sewage and improve the interfacial adsorption and sweep flocculation performance. The diacetone acrylamide copolymer has the function of clarifying suspended solids and has strong water purification ability.

[0042] According to the present invention, preferably, the initiator is at least one of an inorganic peroxide initiator, a water-soluble redox system initiator, and a water-soluble azo compound.

[0043] In the present invention, preferably, the inorganic peroxide initiator is at least one of ammonium persulfate, potassium persulfate, and sodium persulfate.

[0044] In the present invention, preferably, the water-soluble redox system is at least one of hydrogen peroxide and at least one of sodium thiosulfate, ferrous chloride, and ascorbic acid.

[0045] In the present invention, preferably, the water-soluble azo compound is at least one of dimethyl 2,2'-azobis(isobutyrate), 2,2'-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride, and azobis(isobutyramidine) dihydrochloride.

[0046] In the present invention, preferably, the amount of the initiator accounts for 0.05 to 1 wt% of the total weight of the reaction monomers, preferably 0.2 to 0.6 wt%.

[0047] In the present invention, preferably, the weight ratio of the first part of the initiator to the second part of the initiator is (1 to 3):1.

[0048] According to the present invention, preferably, in step (1), the polymerization temperature is 10 to 80 °C, preferably 20 to 60 °C, and the reaction time is 2 to 4 h.

[0049] According to the present invention, preferably, in step (2), the reaction time is 3 to 5 h.

[0050] According to the present invention, preferably, the emulsifier is an anionic emulsifier and / or a non-ionic emulsifier; the anionic emulsifier is selected from at least one of sodium dodecyl sulfate, sodium dodecyl sulfonate, sodium dodecyl benzene sulfonate, and sodium succinate sulfonate; the non-ionic emulsifier is selected from at least one of Span, Tween, alkylphenol polyoxyethylene ether, and isomeric alcohol polyoxyethylene ether; preferably, the emulsifier is prepared by compounding an anionic emulsifier and a non-ionic emulsifier, and the mass ratio of the anionic emulsifier to the non-ionic emulsifier is (0.5 - 2):1.

[0051] According to the present invention, preferably, the solvent is deionized water;

[0052] According to the present invention, preferably, based on the total weight of the cationic unsaturated monomer, the acrylamide monomer containing an aromatic ring structure, the alkyl acrylamide monomer, and the acrylamide monomer as the total weight of the reaction monomers, the addition amount of the deionized water is 0.5 - 5 times, preferably 1 - 3 times, the total weight of the reaction monomers; the addition amount of the emulsifier is 1 - 10 wt% of the total weight of the reaction monomers, preferably 2 - 8 wt%.

[0053] The third aspect of the present invention provides the application of the cationic polymer containing functional acrylamide prepared by the preparation method in the preparation of an oilfield produced water treatment agent.

[0054] The following further illustrates the present invention with reference to the examples, but the scope of the present invention is not limited to these examples.

[0055] Example 1

[0056] Operating steps:

[0057] Step 1, add 180 g of deionized water to the reaction kettle, add 2.76 g of cetyltrimethylammonium bromide and 1.38 g of Tween 80 under stirring conditions, after mixing for 20 minutes, add 80 g of methacryloyloxyethyltrimethylammonium chloride, 10 g of dodecylacrylamide, and 5 g of benzylacrylamide, and emulsify for 5 - 20 minutes at a rotation speed of 800 r / min to obtain an emulsion;

[0058] Step 2, heat up to 50 °C, continuously introduce nitrogen, and uniformly dropwise add 6 g of an azodiisobutyramidine hydrochloride V50 initiator solution (5%), complete the dropwise addition in 0.5 hours, and react for 3 hours;

[0059] Step 3, dissolve 5 g of diacetone acrylamide monomer in 10 g of water, and dropwise add it to the reaction system together with 4 g of an azodiisobutyramidine hydrochloride V50 initiator solution (5%) within 0.5 hours, continue the constant temperature reaction for 3 - 5 hours, cool down to room temperature and discharge to obtain the cationic polymer.

[0060] Example 2

[0061] Operation steps:

[0062] Step 1: Add 180 g of deionized water into the reactor. Under stirring conditions, add 2.76 g of cetyltrimethylammonium bromide and 1.38 g of Tween 80. After mixing for 20 minutes, add 75 g of methacryloyloxyethyltrimethylammonium chloride, 10 g of dodecylacrylamide, and 10 g of benzylacrylamide. Emulsify for 5 - 20 minutes at a rotation speed of 800 r / min to obtain an emulsion;

[0063] Step 2: Heat up to 50 °C, continuously introduce nitrogen gas, and uniformly dropwise add 6 g of azodiisobutyramidine hydrochloride V50 initiator solution (5%). The dropping is completed within 0.5 hour, and react for 3 hours;

[0064] Step 3: Dissolve 5 g of diacetoneacrylamide monomer in 10 g of water, and dropwise add it together with 4 g of azodiisobutyramidine hydrochloride V50 initiator solution (5%) into the reaction system. The dropping is completed within 0.5 hour, continue the constant-temperature reaction for 3 - 5 hours, cool down to room temperature and discharge to obtain the cationic polymer.

[0065] Example 3

[0066] Operation steps:

[0067] Step 1: Add 180 g of deionized water into the reactor. Under stirring conditions, add 2.76 g of cetyltrimethylammonium bromide and 1.38 g of Tween 80. After mixing for 20 minutes, add 65 g of methacryloyloxyethyltrimethylammonium chloride, 20 g of dodecylacrylamide, and 10 g of benzylacrylamide. Emulsify for 5 - 20 minutes at a rotation speed of 800 r / min to obtain an emulsion;

[0068] Step 2: Heat up to 50 °C, continuously introduce nitrogen gas, and uniformly dropwise add 6 g of azodiisobutyramidine hydrochloride V50 initiator solution (5%). The dropping is completed within 0.5 hour, and react for 3 hours;

[0069] Step 3: Dissolve 5 g of diacetoneacrylamide monomer in 10 g of water, and dropwise add it together with 4 g of azodiisobutyramidine hydrochloride V50 initiator solution (5%) into the reaction system. The dropping is completed within 0.5 hour, continue the constant-temperature reaction for 3 - 5 hours, cool down to room temperature and discharge to obtain the cationic polymer.

[0070] Example 4

[0071] Operation steps:

[0072] Step 1: Add 180 g of deionized water into the reaction kettle. Under stirring conditions, add 2.76 g of cetyltrimethylammonium bromide and 1.38 g of Tween 80. After mixing for 20 minutes, add 75 g of methacryloyloxyethyltrimethylammonium chloride, 10 g of dodecylacrylamide, and 5 g of benzylacrylamide. Emulsify for 5 - 20 minutes at a rotation speed of 800 r / min to obtain an emulsion;

[0073] Step 2: Heat up to 50 °C, continuously introduce nitrogen, and uniformly dropwise add 6 g of azodiisobutyramidine hydrochloride V50 initiator solution (5%). The dropping is completed within 0.5 hour, and react for 3 hours;

[0074] Step 3: Dissolve 10 g of diacetone acrylamide monomer in 10 g of water, and dropwise add it to the reaction system together with 4 g of azodiisobutyramidine hydrochloride V50 initiator solution (5%). The dropping is completed within 0.5 hour, continue the constant temperature reaction for 3 - 5 hours, cool down to room temperature and discharge to obtain the said cationic polymer.

[0075] Example 5

[0076] Operating steps:

[0077] Step 1: Add 175 g of deionized water into the reaction kettle. Under stirring conditions, add 2.76 g of cetyltrimethylammonium bromide and 1.38 g of Tween 80. After mixing for 20 minutes, add 70 g of methacryloyloxyethyltrimethylammonium chloride, 10 g of dodecylacrylamide, and 5 g of benzylacrylamide. Emulsify for 5 - 20 minutes at a rotation speed of 800 r / min to obtain an emulsion;

[0078] Step 2: Heat up to 50 °C, continuously introduce nitrogen, and uniformly dropwise add 6 g of azodiisobutyramidine hydrochloride V50 initiator solution (5%). The dropping is completed within 0.5 hour, and react for 3 hours;

[0079] Step 3: Dissolve 15 g of diacetone acrylamide monomer in 15 g of water, and dropwise add it to the reaction system together with 4 g of azodiisobutyramidine hydrochloride V50 initiator solution (5%). The dropping is completed within 0.5 hour, continue the constant temperature reaction for 3 - 5 hours, cool down to room temperature and discharge to obtain the said cationic polymer.

[0080] Example 6

[0081] Operating steps:

[0082] Step 1: Add 170 g of deionized water into the reaction kettle. Under stirring conditions, add 2.76 g of cetyltrimethylammonium bromide and 1.38 g of Tween 80. After mixing for 20 minutes, add 60 g of methacryloyloxyethyltrimethylammonium chloride, 10 g of dodecylacrylamide, and 10 g of benzylacrylamide. Emulsify for 5 - 20 minutes at a rotation speed of 800 r / min to obtain an emulsion;

[0083] Step 2: Heat up to 50°C, continuously introduce nitrogen gas, and uniformly drip-feed 6 g of azodiisobutyramidine hydrochloride V50 initiator solution (5%). The dripping is completed within 0.5 hour, and the reaction proceeds for 3 hours.

[0084] Step 3: Dissolve 20 g of diacetone acrylamide monomer in 20 g of water, and drip-feed it together with 4 g of azodiisobutyramidine hydrochloride V50 initiator solution (5%) into the reaction system. The dripping is completed within 0.5 hour, and the reaction continues under constant temperature for 3 - 5 hours. Then, cool it down to room temperature and discharge to obtain the cationic polymer.

[0085] Example 7

[0086] Operation steps:

[0087] Step 1: Add 170 g of deionized water to the reaction kettle, add 4.14 g of cetyltrimethylammonium bromide under stirring conditions, mix for 20 minutes, then add 60 g of methacryloyloxyethyl trimethyl ammonium chloride, 10 g of dodecyl acrylamide, and 10 g of benzyl acrylamide, and emulsify for 5 - 20 minutes at a rotation speed of 800 r / min to obtain an emulsion.

[0088] Step 2: Heat up to 50°C, continuously introduce nitrogen gas, and uniformly drip-feed 6 g of azodiisobutyramidine hydrochloride V50 initiator solution (5%). The dripping is completed within 0.5 hour, and the reaction proceeds for 3 hours.

[0089] Step 3: Dissolve 20 g of diacetone acrylamide monomer in 20 g of water, and drip-feed it together with 4 g of azodiisobutyramidine hydrochloride V50 initiator solution (5%) into the reaction system. The dripping is completed within 0.5 hour, and the reaction continues under constant temperature for 3 - 5 hours. Then, cool it down to room temperature and discharge to obtain the cationic polymer.

[0090] Example 8

[0091] Operation steps:

[0092] Step 1: Add 170 g of deionized water to the reaction kettle, add 2.76 g of cetyltrimethylammonium bromide and 1.38 g of Tween 80 under stirring conditions, mix for 20 minutes, then add 50 g of methacryloyloxyethyl trimethyl ammonium chloride, 10 g of dodecyl acrylamide, and 10 g of benzyl acrylamide, and emulsify for 5 - 20 minutes at a rotation speed of 800 r / min to obtain an emulsion.

[0093] Step 2: Heat up to 50°C, continuously introduce nitrogen gas, and uniformly drip-feed 6 g of azodiisobutyramidine hydrochloride V50 initiator solution (5%). The dripping is completed within 0.5 hour, and the reaction proceeds for 3 hours.

[0094] Step 3: Dissolve 30 g of diacetone acrylamide monomer in 20 g of water, and dropwise add it together with 4 g of azodiisobutyramidine hydrochloride V50 initiator solution (5%) into the reaction system. The dropping is completed within 0.5 h, and the reaction is continued at a constant temperature for 3 - 5 h. Then, it is cooled to room temperature and discharged to obtain the cationic polymer.

[0095] Example 9

[0096] Operation steps:

[0097] Step 1: Add 190 g of deionized water into the reaction kettle. Under stirring conditions, add 2.76 g of cetyltrimethylammonium bromide and 1.38 g of Tween 80. After mixing for 20 minutes, add 60 g of methacryloyloxyethyltrimethylammonium chloride, 10 g of dodecylacrylamide, 10 g of benzylacrylamide, and 20 g of diacetone acrylamide monomer. Emulsify for 5 - 20 minutes at a rotation speed of 800 r / min to obtain an emulsion.

[0098] Step 2: Heat up to 50 °C, continuously introduce nitrogen, and uniformly dropwise add 10 g of azodiisobutyramidine hydrochloride V50 initiator solution (5%). The dropping is completed within 0.5 h, and the reaction is carried out for 6 - 8 h. Then, it is cooled to room temperature and discharged to obtain the cationic polymer.

[0099] Comparative Example 1:

[0100] Step 1: Add 190 g of deionized water into the reaction kettle. Under stirring conditions, add 2.76 g of cetyltrimethylammonium bromide and 1.38 g of Tween 80. After mixing for 20 minutes, add 80 g of methacryloyloxyethyltrimethylammonium chloride, 10 g of dodecylacrylamide, 10 g of benzylacrylamide. Emulsify for 5 - 20 minutes at a rotation speed of 800 r / min to obtain an emulsion.

[0101] Step 2: Heat up to 50 °C, continuously introduce nitrogen, and uniformly dropwise add 6 g of azodiisobutyramidine hydrochloride V50 initiator solution (5%). The dropping is completed within 0.5 h, and the reaction is carried out for 6 - 8 h. Then, it is cooled to room temperature and discharged to obtain the cationic polymer.

[0102] Comparative Example 2:

[0103] Step 1: Add 190 g of deionized water into the reaction kettle. Under stirring conditions, add 2.76 g of cetyltrimethylammonium bromide and 1.38 g of Tween 80. After mixing for 20 minutes, add 80 g of methacryloyloxyethyltrimethylammonium chloride, 20 g of dodecylacrylamide. Emulsify for 5 - 20 minutes at a rotation speed of 800 r / min to obtain an emulsion.

[0104] Step 2: Heat up to 50°C, continuously introduce nitrogen, and uniformly dropwise add 10 g of an azodiisobutyramidine hydrochloride V50 initiator solution (5%). The dropping is completed in 0.5 hour, and the reaction lasts for 6 - 8 hours. Then cool down to room temperature and discharge to obtain the cationic polymer.

[0105] Comparative Example 3

[0106] SF-Y001 type cationic polyacrylamide, produced by Wenxian Sifang Water Treatment Materials Co., Ltd.

[0107] Test Example 1

[0108] The performance detection of the cationic polymer is carried out in accordance with the petroleum industry standards SY / T0530 - 93, SY / T 5797 - 93, and SY / T5329 - 94. The bottle test method is adopted to observe and record the oil-water phase and interface conditions; an ultraviolet spectrophotometer is used to test the oil content in the sewage; a filtration experimental device is used to test the suspended solid particle content.

[0109] Add the above Examples 1 - 9 and Comparative Examples 1 - 2 to the produced sewage of Chengdong United Station in Hekou Oil Production Plant. The oil content in the sewage is 134 mg / L, the suspended solid particle content is 85 mg / L, the dosing concentration of the cationic polymer is 10 mg / L, and the reaction is carried out at 50°C for 0.5 hour, and the observation and test are carried out according to the industry standards.

[0110] The test performances of the examples and comparative examples are shown in Table 1.

[0111] Table 1 Performance Evaluation of Cationic Polymer

[0112]

[0113]

[0114] It can be seen from the test results that appropriately increasing the proportion of acrylamide with aromatic ring structure and alkyl acrylamide is beneficial to improving the oil removal rate, and diacetone acrylamide can improve the effect of removing solid suspended particles. The oil removal rate and the effect of removing solid suspended particles in Example 6 are the best, and the water purification ability is significantly better than that of SF-Y001 type cationic polyacrylamide and Comparative Examples 1 - 2.

[0115] The embodiments of the present invention have been described above. The above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations are obvious to those of ordinary skill in the art in the technical field without departing from the scope and spirit of the described embodiments.

[0116] The endpoints and any values in the ranges disclosed herein are not limited to the exact ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

Claims

1. A cationic polymer containing functional acrylamide, characterized in that, The cationic polymer includes structural units derived from cationic unsaturated monomers, structural units derived from acrylamide monomers, structural units derived from alkenylamide monomers containing an aromatic ring structure, and structural units derived from alkylalkenylamide monomers.

2. The cationic polymer containing functional acrylamide according to claim 1, wherein, Based on the total amount of the structural units of the polymer, the content of the structural units derived from cationic unsaturated monomers is 40-90 wt%, preferably 60-85 wt%, the content of the structural units derived from acrylamide monomers is 1-40 wt%, preferably 5-25 wt%, the content of the structural units derived from alkenylamide monomers containing an aromatic ring structure is 2-15 wt%, preferably 5-11 wt%, and the content of the structural units derived from alkylalkenylamide monomers is 5-30 wt%, preferably 5-25 wt%.

3. The cationic polymer containing functional acrylamide according to claim 1, wherein, The structural formulas of the cationic unsaturated monomers, acrylamide monomers, alkenylamide monomers containing an aromatic ring structure, and alkylalkenylamide monomers are as follows: Among them, A is a cationic unsaturated monomer, B is an acrylamide monomer, C is an alkenylamide monomer containing an aromatic ring structure, and D is an alkylalkenylamide monomer; In the formula, R1, R2, R4, and R6 are each independently H or an alkyl group with 1-5 carbon atoms, R3 is an alkylene group with 1-5 carbon atoms, R5 is an alkyl group with 1-18 carbon atoms, preferably an alkyl group with 12-18 carbon atoms, and X is a halogen, preferably Cl or Br.

4. The cationic polymer containing functional acrylamide according to claim 3, wherein, The structural formula of the cationic polymer is as follows: In the formula, a, b, c, d, and e represent the number of repeating units, and a, b, c, d, and e are all non-zero natural numbers.

5. The cationic polymer containing functional acrylamide according to claim 4, wherein, The cationic unsaturated monomer is (meth)acryloyloxyethyltrimethylammonium chloride; The acrylamide monomer is diacetone acrylamide; The alkenylamide monomer containing an aromatic ring structure is benzyl acrylamide; The alkylalkenylamide monomer is at least one of dodecyl acrylamide, hexadecyl acrylamide, and octadecyl acrylamide.

6. The preparation method of the cationic polymer containing functional acrylamide according to any one of claims 1-5, characterized in that, It includes the following steps: In the presence of an initiator, the cationic unsaturated monomer, the alkenylamide monomer containing an aromatic ring structure, the alkylacrylamide monomer, and the acrylamide monomer are subjected to a contact reaction to obtain the cationic polymer.

7. The preparation method according to claim 6, wherein, Based on the total weight of the reaction monomers, the addition amount of the cationic unsaturated monomer is 40-90 wt%, preferably 60-85 wt%, the addition amount of the acrylamide monomer is 1-40 wt%, preferably 5-25 wt%, the addition amount of the alkenylamide monomer containing an aromatic ring structure is 2-15 wt%, preferably 5-11 wt%, and the addition amount of the alkylalkenylamide monomer is 5-30 wt%, preferably 5-25 wt%.

8. The preparation method according to claim 6 or 7, wherein, It includes the following steps: (1) Under the protection of an inert gas, the cationic unsaturated monomer, the alkenylamide monomer containing an aromatic ring structure, and the alkylacrylamide monomer are mixed, heated to the polymerization temperature, and the first part of the initiator is added dropwise for reaction; (2) The acrylamide monomer and the second part of the initiator are added dropwise to the reaction system in step (1), and the reaction is continued to obtain the cationic polymer.

9. The preparation method according to claim 8, wherein, It is carried out by emulsion polymerization. Step (1) includes: (a) Dissolve the emulsifier in a solvent, add a cationic unsaturated monomer, an acrylamide monomer containing an aromatic ring structure, and an alkylacrylamide monomer, and emulsify to obtain an emulsion; (b) Under the protection of an inert gas, heat the emulsion obtained in step (a) to the polymerization temperature, and dropwise add the first part of the initiator for reaction.

10. The preparation method according to claim 9, wherein, The initiator is at least one of an inorganic peroxide initiator, a water-soluble redox system initiator, and a water-soluble azo compound; Preferably, the inorganic peroxide initiator is at least one of ammonium persulfate, potassium persulfate, and sodium persulfate; Preferably, the water-soluble redox system is at least one of hydrogen peroxide and sodium thiosulfate, ferrous chloride and ascorbic acid; Preferably, the water-soluble azo compound is at least one of dimethyl 2,2-azobisisobutyrate, 2,2-azobis[2-(2-imidazolinyl)propane]dihydrochloride, and azobis(isobutyramidine)dihydrochloride; The dosage of the initiator accounts for 0.05-1 wt% of the total weight of the reaction monomers, preferably 0.2-0.6 wt%; The weight ratio of the first part of the initiator to the second part of the initiator is (1-3):

1.

11. The preparation method according to claim 9, wherein, In step (1), the polymerization temperature is 10-80°C, preferably 20-60°C, and the reaction time is 2-4 h; In step (2), the reaction time is 3-5 h.

12. The preparation method according to claim 9, wherein, The emulsifier is an anionic emulsifier and / or a non-ionic emulsifier; the anionic emulsifier is selected from at least one of sodium dodecyl sulfate, sodium dodecyl sulfonate, sodium dodecylbenzenesulfonate, and sodium succinate sulfonate; the non-ionic emulsifier is selected from at least one of span, tween, alkylphenol polyoxyethylene ether, and isomeric alcohol polyoxyethylene ether; preferably, the emulsifier is prepared by compounding an anionic emulsifier and a non-ionic emulsifier, and the mass ratio of the anionic emulsifier to the non-ionic emulsifier is (0.5-2):1; The solvent is deionized water; Based on the total weight of the cationic unsaturated monomer, the acrylamide monomer containing an aromatic ring structure, the alkylacrylamide monomer, and the acrylamide monomer as the total weight of the reaction monomers, the addition amount of the deionized water is 0.5-5 times the total weight of the reaction monomers, preferably 1-3 times; the addition amount of the emulsifier is 1-10 wt% of the total weight of the reaction monomers, preferably 2-8 wt%.

13. Use of the cationic polymer containing functional acrylamide according to any one of claims 1-5 or the cationic polymer containing functional acrylamide prepared by the preparation method according to any one of claims 6-12 in the preparation of an oilfield produced water treatment agent.

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