Reverse demulsifier as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of petroleum industry, and relates to a reverse demulsifier as well as a preparation method and application thereof. The reverse demulsifier comprises a structural unit derived from a cationic unsaturated monomer, a structural unit derived from an acrylamide monomer, a structural unit derived from a polyether monomer with a double-bond-containing end group and a structural unit derived from a hydrophobic monomer with a double-bond-containing end group. Based on the total weight of all the structural units in the reverse demulsifier, the content of the structural unit derived from the cationic unsaturated monomer is 30-65 wt%, the content of the structural unit derived from the acrylamide monomer is 10-45 wt%, the content of the structural unit derived from the polyether monomer with the end group containing double bonds is 5-22 wt%, and the content of the structural unit derived from the polyether monomer with the end group containing double bonds is 5-20 wt%. The content of the structural unit derived from the hydrophobic monomer containing double bonds at the end group is 2-15 wt%. The reverse demulsifier disclosed by the invention has the characteristics of high dehydration speed, clear dehydrated water, suspended solid particles and low oil content.

Description

Technical Field

[0001] The present invention belongs to the technical field of the petroleum industry, and particularly relates to an inverse demulsifier, 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 the produced fluid 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 very complex properties of the produced water in oilfields, with characteristics such as high viscosity, strong emulsification stability of oil droplets and suspended solids in water, increasing the difficulty of oil-water separation, and the problem of treating oil-in-water (O / W) emulsions is becoming increasingly serious.

[0003] An inverse demulsifier must be added to treat the oily sewage to demulsify it for the purpose of removing oil. At present, 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 discharge and reinjection, etc. Therefore, there is an urgent need to develop a new type of high-efficiency water-purifying inverse demulsifier to ensure the continuous and stable production of oilfields.

[0004] Cationic inverse demulsifiers are the main type of inverse demulsifiers used in the treatment of oily sewage at present. The interface of the produced water O / W emulsion generally has a negative charge. The cationic group 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 the produced water in oilfields.

[0005] Acrylate inverse demulsifiers are a research hotspot in recent years. They can associate and solubilize with hydrophobic organic substances in oily sewage, interact with hydrophobic oil droplets, enhance the bridging demulsification effect, have good demulsification and dehydration effects, clear oil-water interfaces, and high oil removal rates, but the demulsification speed is slow. Summary of the Invention

[0006] In view of the above-mentioned state of the prior art, the inventors of the present invention have conducted extensive and in-depth experimental research and found that the non-ionic polyether structure can be quickly adsorbed onto the oil-water interface, reducing the strength of the interfacial film and achieving a rapid demulsification effect; polyacrylamide is a widely used sewage treatment agent that can cause suspended particles to aggregate and settle through bridging action and has good flocculation effect. By grafting the above functional groups onto the molecular chain of the cationic reverse demulsifier, it can be quickly dispersed to the oil-water interface, improving the interfacial adsorption and sweeping and coalescence performance, reducing the strength of the oil-water interfacial film and the electrostatic repulsion force between oil droplets, enhancing the demulsification efficiency and oil removal rate, and featuring fast dehydration speed, clear dehydrated water, low suspended solid particles and oil content.

[0007] The object of the present invention is to provide a reverse demulsifier and its preparation method and application. The rapid water purification type reverse demulsifier is prepared by polymerizing cationic unsaturated monomers with acrylamide monomers, polyether monomers, hydrophobic monomers and crosslinkable monomers. By introducing polyether structure, amide group structure and hydrophobic functional groups, the dehydration speed and water purification ability of the reverse demulsifier are improved, and it has good effects on demulsifying and removing oil and removing suspended solid particles from oily sewage. Further, the stability of the reverse demulsifier is improved by the crosslinkable monomers, and it has better effects on demulsifying and removing oil and removing suspended solid particles from oily sewage.

[0008] To achieve the object of the present invention, in the first aspect of the present invention, a reverse demulsifier is provided. The reverse demulsifier includes a structural unit derived from a cationic unsaturated monomer, a structural unit derived from an acrylamide monomer, a structural unit derived from a polyether monomer with a double bond at the end group, and a structural unit derived from a hydrophobic monomer with a double bond at the end group.

[0009] In the second aspect of the present invention, a preparation method of the reverse demulsifier is provided, including the following steps:

[0010] Mix the cationic unsaturated monomer, acrylamide monomer and hydrophobic monomer, heat up to the polymerization temperature, and dropwise add the polyether monomer and initiator for reaction to obtain the reverse demulsifier.

[0011] In the third aspect of the present invention, an application of the reverse demulsifier in the treatment of oily sewage is provided.

[0012] The present invention has the following beneficial effects:

[0013] (1) The cationic polymer containing polyether, amide group and hydrophobic functional groups provided by the present invention improves the dehydration speed and water purification effect of the reverse demulsifier, has 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.

[0014] (2) The present invention preferably adopts 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.

[0015] (3) The reverse demulsifier provided by the present invention can be used alone, or can be compounded with other existing reverse demulsifiers or flocculants according to the properties of the water-in-oil emulsion of the produced liquid, so as to improve the universality of the reverse demulsifier.

[0016] Other features and advantages of the present invention will be described in detail in the following specific embodiments section. Specific Embodiments

[0017] The following will detail the specific embodiments of the present invention. It should be understood that the specific embodiments described herein are only for explaining and illustrating the present invention, and are not used to limit the present invention.

[0018] In order to achieve the object of the present invention, a first aspect of the present invention provides a reverse demulsifier, which comprises a structural unit derived from a cationic unsaturated monomer, a structural unit derived from an acrylamide monomer, a structural unit derived from a polyether monomer with a double bond at the end group, and a structural unit derived from a hydrophobic monomer with a double bond at the end group.

[0019] According to the present invention, preferably, based on the total weight of all structural units in the reverse demulsifier, the content of the structural unit derived from the cationic unsaturated monomer is 30-65 wt%, preferably 40-55 wt%, the content of the structural unit derived from the acrylamide monomer is 10-45 wt%, preferably 20-35 wt%, the content of the structural unit derived from the polyether monomer with a double bond at the end group is 5-22 wt%, preferably 10-18 wt%, and the content of the structural unit derived from the hydrophobic monomer with a double bond at the end group is 2-15 wt%, preferably 5-12 wt%.

[0020] According to the present invention, preferably, the structural formulas of the cationic unsaturated monomer, the acrylamide monomer, the polyether monomer with a double bond at the end group, and the hydrophobic monomer with a double bond at the end group are as follows:

[0021]

[0022] Among them, A is a cationic unsaturated monomer, B is an acrylamide monomer, C is a polyether monomer with a double bond at the end group, and D is a hydrophobic monomer with a double bond at the end group;

[0023] In the formula, R1, R7, and R8 are each independently H or an alkyl group of C1-C5, R2 is an alkylene group of C1-C5, R3, R4, R5, R6, and R9 are each independently an alkyl group of C1-C5, X is a halogen, preferably Cl or Br, m = 1-100, and n = 1-100.

[0024] According to the present invention, preferably, the cationic unsaturated monomer is (meth)acryloyloxyethyl trimethyl ammonium chloride and / or dimethyldiallyl ammonium chloride, preferably (meth)acryloyloxyethyl trimethyl ammonium chloride;

[0025] According to the present invention, preferably, the acrylamide monomer is diacetone acrylamide.

[0026] According to the present invention, preferably, the polyether monomer with a double bond at the end group is a polyoxyethylene polyoxypropylene ether with a double bond at the end group, preferably a polyoxyethylene polyoxypropylene ether with an alcohol having a C2-C6 alkenyl group as the initiator, and more preferably a polyoxyethylene polyoxypropylene ether with allyl alcohol as the initiator.

[0027] According to the present invention, preferably, the hydrophobic monomer with a double bond at the end group is at least one of butyl acrylate, methyl methacrylate, lauryl methacrylate, 2-ethylhexyl acrylate, and dodecyl acrylate, preferably butyl acrylate.

[0028] According to the present invention, preferably, the reverse demulsifier further comprises a structural unit derived from a crosslinkable monomer, and the structural unit derived from the crosslinkable monomer is introduced into the polymer structure in a crosslinked copolymerization form.

[0029] According to the present invention, preferably, the crosslinkable monomer is selected from compounds of olefins containing two or more unsaturated double bonds, preferably selected from at least one of N,N'-methylenebisacrylamide, trimethylolpropane triacrylate, diethylene glycol dimethacrylate, butanediol dimethacrylate, butanediol diacrylate, and divinylbenzene.

[0030] According to the present invention, preferably, based on the total weight of all structural units in the reverse demulsifier, the content of the structural unit derived from the crosslinkable monomer is 0.001-2 wt%, preferably 0.01-0.2 wt%.

[0031] The second aspect of the present invention provides a preparation method of the reverse demulsifier, comprising the following steps:

[0032] Mix the cationic unsaturated monomer, the acrylamide monomer, and the hydrophobic monomer with a double bond at the end group, heat up to the polymerization temperature, and dropwise add the polyether monomer with a double bond at the end group and the initiator for reaction to obtain the reverse demulsifier.

[0033] According to the present invention, preferably, based on 100 parts by weight of the total reaction monomers, the addition amount of the cationic unsaturated monomer is 30 to 65 parts, preferably 40 to 55 parts; the addition amount of the acrylamide monomer is 10 to 45 parts, preferably 20 to 35 parts; the addition amount of the polyether monomer with a double bond at the end group is 5 to 22 parts, preferably 10 to 18 parts; the addition amount of the hydrophobic monomer with a double bond at the end group is 2 to 15 parts, preferably 5 to 12 parts.

[0034] According to the present invention, preferably, it further includes a crosslinking reaction step, including the following steps:

[0035] (1) Mix the cationic unsaturated monomer, the acrylamide monomer, and the hydrophobic monomer with a double bond at the end group, heat up to the polymerization temperature, and dropwise add the polyether monomer with a double bond at the end group and the first part of the initiator for reaction;

[0036] (2) Dropwise add the crosslinkable monomer and the second part of the initiator into the reaction system of step (1), and continue the reaction to obtain the reverse demulsifier.

[0037] According to the present invention, preferably, based on 100 parts by weight of the total reaction monomers, the addition amount of the crosslinkable monomer is 0.001 to 2 parts, preferably 0.01 to 0.2 parts.

[0038] According to the present invention, preferably, the initiator is at least one of inorganic peroxide initiators, water-soluble redox system initiators, and water-soluble azo compounds.

[0039] In the present invention, more preferably, the inorganic peroxide initiator is at least one of ammonium persulfate, potassium persulfate, and sodium persulfate.

[0040] In the present invention, more preferably, the water-soluble redox system initiator is at least one of hydrogen peroxide and at least one of sodium thiosulfate, ferrous chloride, and ascorbic acid.

[0041] In the present invention, more 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) hydrochloride.

[0042] In the present invention, more preferably, based on the total weight of the cationic unsaturated monomer, the acrylamide monomer, the hydrophobic monomer with a double bond at the end group, the polyether monomer with a double bond at the end group, and the crosslinkable monomer as the total weight of the reaction monomers, the addition amount of the initiator is 0.05 to 1 wt% of the total mass of the reaction monomers, preferably 0.2 to 0.6 wt%.

[0043] In the present invention, further preferably, the weight ratio of the first part of the initiator to the second part of the initiator is (2-4):1.

[0044] According to the present invention, preferably, in step (1), the polymerization temperature is 10-100 °C, preferably 20-70 °C, and the reaction time is 2-4 h; in step (2), the reaction time is 3-5 h.

[0045] According to the present invention, preferably, the preparation method is carried out by emulsion polymerization, and step (1) includes:

[0046] (a) Dissolve the emulsifier in the solvent, add the cationic unsaturated monomer, acrylamide monomer and the hydrophobic monomer with a double bond at the end group, and emulsify to obtain an emulsion;

[0047] (b) Under the protection of an inert gas, heat the emulsion obtained in step (a) to the polymerization temperature, and dropwise add the polyether monomer with a double bond at the end group and the first part of the initiator for reaction.

[0048] In the present invention, the cationic unsaturated monomer, acrylamide monomer, polyether with a double bond at the end group, hydrophobic monomer, etc. are polymerized by emulsion polymerization and other methods. The obtained polymer is a milky white liquid. Amide groups, polyether structures and hydrophobic functional groups are introduced into the molecular chain segments, which can quickly adsorb to the oil-water interface, improve the interface adsorption and sweeping and coalescence performance, reduce the interface film strength and the electrostatic repulsion between oil droplets, have a fast dehydration speed and strong water purification ability.

[0049] According to the present invention, preferably, the emulsifier is an anionic emulsifier and / or a non-ionic emulsifier; the anionic emulsifier is preferably 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 preferably 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 (1-3):1.

[0050] According to the present invention, preferably, the solvent is deionized water.

[0051] According to the present invention, preferably, based on the total weight of the cationic unsaturated monomer, acrylamide monomer, hydrophobic monomer with a double bond at the end group, polyether monomer with a double bond at the end group and the crosslinkable monomer as the total weight of the reaction monomers, the addition amount of the deionized water is 1-5 times, preferably 2.5-4 times the total weight of the reaction monomers; the addition amount of the emulsifier accounts for 2-15 wt%, preferably 5-10 wt% of the total weight of the reaction monomers.

[0052] The third aspect of the present invention provides the application of the described reverse demulsifier in the treatment of oily sewage.

[0053] The present invention will be further described below in conjunction with embodiments, but the scope of the present invention is not limited to these embodiments.

[0054] The allyl alcohol polyoxyethylene polyoxypropylene ether monomer was purchased from Jiangsu Haian Petrochemical Factory.

[0055] Example 1

[0056] Operating steps:

[0057] Step 1: Weigh 10 g of deionized water, add 0.1 g of initiators sodium thiosulfate and potassium persulfate (the mass ratio of the two is 1:2), stir evenly, and prepare an initiator solution for standby; weigh 4 g of allyl alcohol polyoxyethylene polyoxypropylene ether monomer and dissolve it in 10 g of deionized water to prepare a polyether monomer solution for standby; weigh 0.5 g of crosslinkable monomer trimethylolpropane triacrylate and dissolve it in 10 g of deionized water to prepare a crosslinkable monomer solution for standby.

[0058] Step 2: Weigh 70 g of deionized water in a beaker, add 1.38 g of sodium dodecyl sulfate and 0.69 g of alkylphenol polyoxyethylene ether OP-10 under stirring conditions, mix for 20 minutes, then add 12 g of methacryloyloxyethyl trimethyl ammonium chloride, 11 g of diacetone acrylamide, and 2 g of butyl acrylate, and emulsify at a rotation speed of 800 r / min for 5 - 20 minutes to obtain an emulsion.

[0059] Step 3: After standing the emulsion for 20 minutes, transfer it to a reaction kettle, heat it to 40 °C, continuously pass nitrogen, and uniformly dropwise add the polyether monomer solution and 7 g of the initiator solution, and complete the dropwise addition in 0.5 hours.

[0060] Step 4: Dropwise add the crosslinkable monomer solution and the remaining initiator solution together into the reaction system, complete the dropwise addition within 0.5 hours, continue the constant temperature reaction for 3 - 5 hours, cool to room temperature and discharge to obtain the described reverse demulsifier.

[0061] Example 2

[0062] Operating steps:

[0063] Step 1: Weigh 10 g of deionized water, add 0.12 g of initiators sodium thiosulfate and potassium persulfate (the mass ratio of the two is 1:2), stir evenly, and prepare an initiator solution for standby; weigh 5 g of allyl alcohol polyoxyethylene polyoxypropylene ether monomer and dissolve it in 10 g of deionized water to prepare a polyether monomer solution for standby; weigh 0.5 g of trimethylolpropane triacrylate and dissolve it in 10 g of deionized water to prepare a crosslinkable monomer solution for standby.

[0064] Step 2: Weigh 80 g of deionized water in a beaker. Under stirring conditions, add 1.56 g of sodium dodecyl sulfate and 0.78 g of polyoxyethylene octylphenol ether OP-10. After mixing for 20 minutes, add 15 g of methacryloyloxyethyl trimethyl ammonium chloride, 10 g of diacetone acrylamide, and 3 g of butyl acrylate. Emulsify for 5 - 20 minutes at a rotation speed of 800 r / min to obtain an emulsion;

[0065] Step 3: Let the emulsion stand for 20 minutes, then transfer it to a reaction kettle, heat it up to 40 °C, continuously pass nitrogen, and uniformly dropwise add the polyether monomer solution and 7 g of the initiator solution. The dropping is completed within 0.5 hour;

[0066] Step 4: Dropwise add the crosslinkable monomer solution and the remaining initiator solution together into the reaction system. The dropping is completed within 0.5 hour, and continue the constant-temperature reaction for 3 - 5 hours, then cool down to room temperature and discharge.

[0067] Example 3

[0068] Operation steps:

[0069] Step 1: Weigh 10 g of deionized water, add 0.12 g of initiators sodium thiosulfate and potassium persulfate (the mass ratio of the two is 1:2), stir evenly, and prepare the initiator solution for standby; Weigh 5 g of allyl polyoxyethylene polyoxypropylene ether monomer and dissolve it in 10 g of deionized water to prepare the polyether monomer solution for standby; Weigh 0.5 g of trimethylolpropane triacrylate and dissolve it in 10 g of deionized water to prepare the crosslinkable monomer solution for standby;

[0070] Step 2: Weigh 80 g of deionized water in a beaker. Under stirring conditions, add 1.56 g of sodium dodecyl sulfate and 0.78 g of polyoxyethylene octylphenol ether OP-10. After mixing for 20 minutes, add 18 g of methacryloyloxyethyl trimethyl ammonium chloride, 7 g of diacetone acrylamide, and 3 g of butyl acrylate. Emulsify for 5 - 20 minutes at a rotation speed of 800 r / min to obtain an emulsion;

[0071] Step 3: Let the emulsion stand for 20 minutes, then transfer it to a reaction kettle, heat it up to 40 °C, continuously pass nitrogen, and uniformly dropwise add the polyether monomer solution and 7 g of the initiator solution. The dropping is completed within 0.5 hour;

[0072] Step 4: Dropwise add the crosslinkable monomer solution and the remaining initiator solution together into the reaction system. The dropping is completed within 0.5 hour, and continue the constant-temperature reaction for 3 - 5 hours, then cool down to room temperature and discharge.

[0073] Example 4

[0074] Operation steps:

[0075] Step 1: Weigh 10 g of deionized water, add 0.1 g of initiators sodium thiosulfate and potassium persulfate (with a mass ratio of 1:2), stir evenly to prepare an initiator solution for standby; weigh 3 g of allyl alcohol polyoxyethylene polyoxypropylene ether monomer and dissolve it in 10 g of deionized water to prepare a polyether monomer solution for standby; weigh 0.5 g of trimethylolpropane triacrylate and dissolve it in 10 g of deionized water to prepare a crosslinkable monomer solution for standby;

[0076] Step 2: Weigh 70 g of deionized water in a beaker, add 1.4 g of sodium dodecyl sulfate and 0.7 g of alkylphenol polyoxyethylene ether OP-10 under stirring conditions, mix for 20 minutes, then add 17 g of methacryloyloxyethyl trimethyl ammonium chloride, 8 g of diacetone acrylamide, and 2 g of butyl acrylate, and emulsify at a rotation speed of 800 r / min for 5 - 20 minutes to obtain an emulsion;

[0077] Step 3: After allowing the emulsion to stand for 20 minutes, transfer it to a reaction kettle, heat it to 40 °C, continuously pass nitrogen, and uniformly dropwise add the polyether monomer solution and 7 g of the initiator solution, and complete the dropping within 0.5 hours;

[0078] Step 4: Dropwise add the crosslinkable monomer solution and the remaining initiator solution together into the reaction system, complete the dropping within 0.5 hours, continue the constant-temperature reaction for 3 - 5 hours, and cool to room temperature for discharging.

[0079] Example 5

[0080] Operating steps:

[0081] Step 1: Weigh 10 g of deionized water, add 0.12 g of 2,2'-azobis(2-methylpropionamidine) dihydrochloride (V50), stir evenly to prepare an initiator solution for standby; weigh 5 g of allyl alcohol polyoxyethylene polyoxypropylene ether monomer and dissolve it in 10 g of deionized water to prepare a polyether monomer solution for standby; weigh 0.5 g of trimethylolpropane triacrylate and dissolve it in 10 g of deionized water to prepare a crosslinkable monomer solution for standby;

[0082] Step 2: Weigh 80 g of deionized water in a beaker, add 1.56 g of sodium dodecyl sulfate and 0.78 g of alkylphenol polyoxyethylene ether OP-10 under stirring conditions, mix for 20 minutes, then add 15 g of methacryloyloxyethyl trimethyl ammonium chloride, 10 g of diacetone acrylamide, and 3 g of butyl acrylate, and stir and emulsify at 800 r / min for 5 - 20 minutes to obtain an emulsion;

[0083] Step 3: After allowing the emulsion to stand for 20 minutes, transfer it to a reaction kettle, heat it to 55 °C, continuously pass nitrogen, and uniformly dropwise add the polyether monomer solution and 7 g of the initiator solution, and complete the dropping within 0.5 hours;

[0084] Step 4: Drop the crosslinkable monomer solution and the remaining initiator solution into the reaction system together, complete the dropping within 0.5 hours, continue the constant-temperature reaction for 3 - 5 hours, and then discharge the product after cooling to room temperature.

[0085] Example 6

[0086] Operation steps:

[0087] Step 1: Weigh 10 g of deionized water, add 0.12 g of sodium thiosulfate and potassium persulfate (the mass ratio of the two is 1:2), stir evenly, and prepare the initiator solution for standby; weigh 5 g of allyl alcohol polyoxyethylene polyoxypropylene ether monomer and dissolve it in 10 g of deionized water to prepare the polyether monomer solution for standby; weigh 0.5 g of N,N'-methylenebisacrylamide and dissolve it in 10 g of deionized water to prepare the crosslinkable monomer solution for standby;

[0088] Step 2: Weigh 80 g of deionized water in a beaker, add 1.56 g of sodium dodecyl sulfate and 0.78 g of alkylphenol polyoxyethylene ether OP-10 under stirring conditions, mix for 20 minutes, then add 15 g of methacryloyloxyethyl trimethyl ammonium chloride, 10 g of diacetone acrylamide, and 3 g of butyl acrylate, and emulsify for 5 - 20 minutes at a rotation speed of 800 r / min to obtain an emulsion;

[0089] Step 3: After standing the emulsion for 20 minutes, transfer it to a reaction kettle, heat it up to 40 °C, continuously introduce nitrogen, and uniformly drop the polyether monomer solution and 7 g of the initiator solution, and complete the dropping within 0.5 hours;

[0090] Step 4: Drop the crosslinkable monomer solution and the remaining initiator solution into the reaction system together, complete the dropping within 0.5 hours, continue the constant-temperature reaction for 3 - 5 hours, and then discharge the product after cooling to room temperature.

[0091] Example 7

[0092] The difference from Example 2 is only that no emulsifier is added. In Step 2, weigh 80 g of deionized water, 15 g of methacryloyloxyethyl trimethyl ammonium chloride, 10 g of diacetone acrylamide, and 3 g of butyl acrylate in a beaker, and fully stir for 30 min at a rotation speed of 800 r / min before the reaction.

[0093] Example 8

[0094] The difference from Example 2 is only that in Step 2, 2.34 g of sodium dodecyl sulfate is added and alkylphenol polyoxyethylene ether OP-10 is not added.

[0095] Example 9

[0096] The difference from Example 2 is only that in Step 1, the crosslinkable monomer solution is not prepared and Step 4 is cancelled.

[0097] Comparative Example 1

[0098] Operation steps:

[0099] Step 1: Weigh 10 g of deionized water, add 0.12 g of sodium thiosulfate and potassium persulfate (the mass ratio of the two is 1:2), stir evenly, and prepare an initiator solution for standby; weigh 0.5 g of trimethylolpropane triacrylate and dissolve it in 10 g of deionized water to prepare a crosslinkable monomer solution for standby;

[0100] Step 2: Weigh 80 g of deionized water in a beaker, add 1.56 g of sodium dodecyl sulfate and 0.78 g of alkylphenol polyoxyethylene ether OP-10 under stirring conditions, mix for 20 minutes, then add 17.5 g of methacryloyloxyethyl trimethyl ammonium chloride, 11.5 g of diacetone acrylamide, and 4 g of butyl acrylate, and emulsify at a rotation speed of 800 r / min for 5 - 20 minutes to obtain an emulsion;

[0101] Step 3: After standing the emulsion for 20 minutes, transfer it to a reaction kettle, heat it to 40°C, continuously introduce nitrogen, and uniformly dropwise add 7 g of the initiator solution, which is completed in 0.5 hours;

[0102] Step 4: Dropwise add the crosslinkable monomer solution and the remaining initiator solution together into the reaction system, which is completed within 0.5 hours, continue the constant-temperature reaction for 3 - 5 hours, and cool to room temperature for discharging.

[0103] Comparative Example 2

[0104] Operation steps:

[0105] Step 1: Weigh 10 g of deionized water, add 0.12 g of sodium thiosulfate and potassium persulfate (the mass ratio of the two is 1:2), stir evenly, and prepare an initiator solution for standby; weigh 5 g of polyoxyethylene polyoxypropylene ether acrylate monomer and dissolve it in 10 g of deionized water to prepare a polyether monomer solution for standby; weigh 0.5 g of N,N'-methylenebisacrylamide and dissolve it in 10 g of deionized water to prepare a crosslinkable monomer solution for standby;

[0106] Step 2: Weigh 80 g of deionized water, and add 16.5 g of methacryloyloxyethyl trimethyl ammonium chloride and 11 g of diacetone acrylamide;

[0107] Step 3: Heat to 40°C, continuously introduce nitrogen, and uniformly dropwise add the polyether monomer solution and 7 g of the initiator solution, which is completed in 0.5 hours;

[0108] Step 4: Dropwise add the crosslinkable monomer solution and the remaining initiator solution together into the reaction system, which is completed within 0.5 hours, continue the constant-temperature reaction for 3 - 5 hours, and cool to room temperature for discharging.

[0109] Comparative Example 3

[0110] Cationic polyacrylamide of type SF-Y001, produced by Wenxian Sifang Water Treatment Materials Co., Ltd.

[0111] Test Example 1

[0112] The performance detection of the reverse demulsifier 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; the ultraviolet spectrophotometer is used to test the oil content in the sewage; the filtration experimental device is used to test the suspended solid particle content.

[0113] Add the above Examples 1 - 9 and Comparative Examples 1 - 3 to the produced sewage of the Bohai No. 3 Joint Station of the Hekou Oil Production Plant. The oil content in the sewage is 55 mg / L, the suspended solid particle content is 65 mg / L, the dosing concentration of the reverse demulsifier is 20 mg / L, react at 50 °C for 0.5 hours, and observe and test according to the industry standards.

[0114] The test performances of the examples and comparative examples are shown in Table 1.

[0115] Table 1 Performance Evaluation of Reverse Demulsifier

[0116]

[0117]

[0118] It can be seen from the test results that compared with Comparative Example 1 and Comparative Example 2, Example 2 obviously has higher demulsification and oil removal and solid suspended particle removal effects. Examples 1 - 9 have good demulsification and oil removal and solid suspended particle removal effects on the produced sewage of the Bohai No. 3 Joint Station, and the water purification ability is significantly better than that of the cationic polyacrylamide of type SF-Y001 and Comparative Examples 1 - 2.

[0119] The embodiments of the present invention have been described above. The above description is exemplary and not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations are obvious to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments.

[0120] The endpoints and any values disclosed herein are not limited to the exact range or value. 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. An inverse demulsifier, characterized in that, The reverse demulsifier comprises structural units derived from cationic unsaturated monomers, structural units derived from acrylamide monomers, structural units derived from polyether monomers with double bonds at the end groups, and structural units derived from hydrophobic monomers with double bonds at the end groups.

2. The demulsifier for reverse phase according to claim 1, wherein, Based on the total weight of all structural units in the reverse demulsifier, the content of the structural units derived from cationic unsaturated monomers is 30 - 65 wt%, preferably 40 - 55 wt%; the content of the structural units derived from acrylamide monomers is 10 - 45 wt%, preferably 20 - 35 wt%; the content of the structural units derived from polyether monomers with double bonds at the end groups is 5 - 22 wt%, preferably 10 - 18 wt%; the content of the structural units derived from hydrophobic monomers with double bonds at the end groups is 2 - 15 wt%, preferably 5 - 12 wt%.

3. The demulsifier for reverse phase according to claim 1, wherein The structural formulas of the cationic unsaturated monomers, acrylamide monomers, polyether monomers with double bonds at the end groups, and hydrophobic monomers with double bonds at the end groups are as follows: Among them, A is a cationic unsaturated monomer, B is an acrylamide monomer, C is a polyether monomer with double bonds at the end groups, and D is a hydrophobic monomer with double bonds at the end groups; In the formula, R1, R7, and R8 are each independently H or an alkyl group with 1 - 5 carbon atoms, R2 is an alkylene group with 1 - 5 carbon atoms, R3, R4, R5, R6, and R9 are each independently an alkyl group with 1 - 5 carbon atoms, X is a halogen, preferably Cl or Br, m = 1 - 100, and n = 1 - 100.

4. The demulsifier according to claim 3, wherein, The cationic unsaturated monomer is (meth)acryloyloxyethyl trimethyl ammonium chloride and / or dimethyldiallyl ammonium chloride, preferably (meth)acryloyloxyethyl trimethyl ammonium chloride; The acrylamide monomer is diacetone acrylamide; The polyether monomer with double bonds at the end groups is a polyoxyethylene polyoxypropylene ether with double bonds at the end groups, preferably a polyoxyethylene polyoxypropylene ether with an alcohol with a C2 - C6 alkenyl group as the initiator, more preferably a polyoxyethylene polyoxypropylene ether with allyl alcohol as the initiator; The hydrophobic monomer with double bonds at the end groups is at least one of butyl acrylate, methyl methacrylate, lauryl methacrylate, 2 - ethylhexyl acrylate, and dodecyl acrylate, preferably butyl acrylate.

5. The demulsifier according to any one of claims 1-4, wherein, The reverse demulsifier further comprises structural units derived from crosslinkable monomers, and the structural units derived from crosslinkable monomers are introduced into the polymer structure in a crosslinked copolymerization form; The crosslinkable monomer is selected from compounds of olefins containing two or more unsaturated double bonds, preferably at least one of N,N'-methylenebisacrylamide, trimethylolpropane triacrylate, diethylene glycol dimethacrylate, butanediol dimethacrylate, butanediol diacrylate, and divinylbenzene; Based on the total weight of all structural units in the reverse demulsifier, the content of the structural units derived from crosslinkable monomers is 0.001 - 2 wt%, preferably 0.01 - 0.2 wt%.

6. The preparation method of the reverse demulsifier according to any one of claims 1-5, characterized in that, Comprising the following steps: Mix a cationic unsaturated monomer, an acrylamide monomer, and a hydrophobic monomer with a double bond at the end group, heat up to the polymerization temperature, and dropwise add a polyether monomer with a double bond at the end group and an initiator to react to obtain the reverse demulsifier.

7. The preparation method according to claim 6, wherein, Based on 100 parts by weight of the total reaction monomers, the addition amount of the cationic unsaturated monomer is 30 - 65 parts, preferably 40 - 55 parts; the addition amount of the acrylamide monomer is 10 - 45 parts, preferably 20 - 35 parts; the addition amount of the polyether monomer with a double bond at the end group is 5 - 22 parts, preferably 10 - 18 parts; the addition amount of the hydrophobic monomer with a double bond at the end group is 2 - 15 parts, preferably 5 - 12 parts.

8. The preparation method according to claim 6 or 7, wherein It also includes a crosslinking reaction step, which includes the following steps: (1) Mix a cationic unsaturated monomer, an acrylamide monomer, and a hydrophobic monomer with a double bond at the end group, heat up to the polymerization temperature, and dropwise add a polyether monomer with a double bond at the end group and the first part of the initiator to react; (2) Dropwise add a crosslinkable monomer and the second part of the initiator into the reaction system of step (1), and continue to react to obtain the reverse demulsifier; Among them, based on 100 parts by weight of the total reaction monomers, the addition amount of the crosslinkable monomer is 0.001 - 2 parts, preferably 0.01 - 0.2 parts.

9. The preparation method according to claim 8, wherein, The initiator is at least one of inorganic peroxide initiators, water-soluble redox system initiators, and water-soluble azo compounds; Preferably, the inorganic peroxide initiator is at least one of ammonium persulfate, potassium persulfate, and sodium persulfate; Preferably, the water-soluble redox system initiator 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'-azobis(isobutyrate), 2,2'-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride, and azobis(isobutyramidine) dihydrochloride; Based on the total weight of the cationic unsaturated monomer, the acrylamide monomer, the hydrophobic monomer with a double bond at the end group, the polyether monomer with a double bond at the end group, and the crosslinkable monomer as the total weight of the reaction monomers, the addition amount of the initiator is 0.05 - 1 wt% of the total mass 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 (2 - 4):

1.

10. The preparation method according to claim 8, wherein, In step (1), the polymerization temperature is 10 - 100 °C, preferably 20 - 70 °C, and the reaction time is 2 - 4 h; In step (2), the reaction time is 3 - 5 h.

11. The preparation method according to claim 8, wherein, The preparation method is carried out by emulsion polymerization. Step (1) includes: (a) Dissolve the emulsifier in a solvent, add a cationic unsaturated monomer, an acrylamide monomer, and a hydrophobic monomer with a double bond at the end group, and emulsify to obtain an emulsion; (b) Under the protection of an inert gas, heat up the emulsion obtained in step (a) to the polymerization temperature, and dropwise add a polyether monomer with a double bond at the end group and the first part of the initiator to react.

12. The preparation method according to claim 11, wherein, The emulsifier is an anionic emulsifier and / or a non-ionic emulsifier; the anionic emulsifier is preferably 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 preferably 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 (1-3):1; The solvent is deionized water; Based on the total weight of the cationic unsaturated monomer, acrylamide monomer, hydrophobic monomer with a double bond at the end, polyether monomer with a double bond at the end, and crosslinkable monomer as the total weight of the reaction monomers, the addition amount of the deionized water is 1-5 times, preferably 2.5-4 times, the total weight of the reaction monomers; the addition amount of the emulsifier accounts for 2-15 wt% of the total weight of the reaction monomers, preferably 5-10 wt%.

13. Application of the reverse demulsifier according to any one of claims 1-5 or the reverse demulsifier prepared by the preparation method according to any one of claims 6-12 in the treatment of oilfield produced water.

Images