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CN-121974420-A - Composite water-cleaning agent for oilfield sewage treatment and preparation method thereof

CN121974420ACN 121974420 ACN121974420 ACN 121974420ACN-121974420-A

Abstract

The application relates to the technical field of oilfield sewage treatment, and particularly discloses a composite water scavenger for oilfield sewage treatment and a preparation method thereof. The composite water-cleaning agent for oilfield sewage treatment is prepared from double modified polyacrylamide, imidazoline quaternary ammonium salt graft copolymer, scale inhibitor, adsorbent, dodecyl dimethyl betaine, coagulant aid and deionized water, wherein the double modified polyacrylamide is prepared by double modification of polyacrylamide by 2, 3-epoxypropyl trimethyl ammonium chloride and hydrophobic monomer, and the imidazoline quaternary ammonium salt graft copolymer is a graft copolymer of imidazoline quaternary ammonium salt, acrylamide and acrylamide-2-methylpropanesulfonic acid. The composite water-cleaning agent can be used for treating high-salt high-oil sewage generated in the middle and later stages of oil field exploitation and the like, has the advantages of strong salt resistance, thorough demulsification and good flocculation effect, can efficiently remove oils and suspended matters, ensures that effluent reaches the standard, and meets the complex sewage treatment requirement of an oil field.

Inventors

  • YAN HAILONG
  • ZHANG LEI
  • CHENG JIAN
  • XU LEI
  • WANG JING

Assignees

  • 西安三维科技发展有限责任公司

Dates

Publication Date
20260505
Application Date
20260408

Claims (10)

  1. 1. The composite water-cleaning agent for oilfield sewage treatment is characterized by comprising the following raw materials in parts by weight: 18-28 parts of double modified polyacrylamide; 10-16 parts of imidazoline quaternary ammonium salt graft copolymer; 6-12 parts of scale inhibitor; 5-10 parts of adsorbent; 1-3 parts of dodecyl dimethyl betaine; 3-7 parts of coagulant aid; 38-58 parts of deionized water; The double modified polyacrylamide is obtained by double modification of polyacrylamide by 2, 3-epoxypropyl trimethyl ammonium chloride and a hydrophobic monomer; The imidazoline quaternary ammonium salt graft copolymer is a graft copolymer of imidazoline quaternary ammonium salt, acrylamide and acrylamide-2-methylpropanesulfonic acid.
  2. 2. The composite water scavenger for oilfield sewage treatment of claim 1, wherein the dual modified polyacrylamide is prepared by the following method: Adding 2, 3-epoxypropyl trimethyl ammonium chloride into polyacrylamide, carrying out cationization reaction for 3-4h under the condition of a value of 7.0-8.0 at 55-75℃, pH, adding a hydrophobic monomer, adding an initiator, reacting for 2-4h under the condition of 60-70 ℃, and carrying out precipitation, washing, vacuum drying and crushing after the reaction is finished to obtain the double modified polyacrylamide.
  3. 3. The compound water scavenger for oilfield sewage treatment of claim 2, wherein the addition of the 2, 3-epoxypropyl trimethyl ammonium chloride is 15-25% of the mass of the polyacrylamide.
  4. 4. The compound water scavenger for oilfield sewage treatment of claim 2, wherein the hydrophobic monomer is cetyl dimethyl allyl ammonium chloride, and the addition amount of the hydrophobic monomer is 5-10% of the mass of the polyacrylamide.
  5. 5. The compound water scavenger for oilfield sewage treatment according to claim 2, wherein the initiator is compounded from ammonium persulfate and sodium bisulphite according to a mass ratio of 1 (0.5-1), and the addition amount of the initiator is 0.3% -0.8% of the total mass of the reaction system.
  6. 6. The composite water scavenger for oilfield sewage treatment of claim 1, wherein the imidazoline quaternary ammonium salt graft copolymer is prepared by the following method: Firstly mixing imidazoline quaternary ammonium salt and acrylamide, adding deionized water for dissolution, regulating the pH value to 6.5-7.5 to obtain a mixed reaction solution, heating the mixed reaction solution to 70-80 ℃, adding an initiator for reaction for 1-2h, adding 2-acrylamide-2-methylpropanesulfonic acid, continuing to react for 2-3h, cooling to room temperature, and carrying out reduced pressure distillation to obtain the imidazoline quaternary ammonium salt graft copolymer.
  7. 7. The compound water scavenger for oilfield sewage treatment of claim 6, wherein the mass ratio of the imidazoline quaternary ammonium salt to the acrylamide to the deionized water is 1 (1.2-1.8) (8-15).
  8. 8. The compound water scavenger for oilfield sewage treatment according to claim 6, wherein the initiator is azobisisobutyronitrile hydrochloride, the addition amount of the initiator is 0.5% -1.0% of the mass of the mixed reaction solution, and the addition amount of the 2-acrylamide-2-methylpropanesulfonic acid is 70% -90% of the mass of the imidazoline quaternary ammonium salt.
  9. 9. The compound water scavenger for oilfield sewage treatment of claim 6, wherein the scale inhibitor is diethyl hydroxyphosphonate.
  10. 10. A method of preparing a composite water scavenger for oilfield sewage treatment according to any one of claims 1-9, comprising the steps of: S1, mixing deionized water and double modified polyacrylamide, heating to 45-55 ℃, and stirring until the deionized water and the double modified polyacrylamide are completely dissolved to obtain a base solution; S2, adding the imidazoline quaternary ammonium salt graft copolymer into the base solution, heating to 60-70 ℃, preserving heat, stirring until the mixture is uniform, then sequentially adding the scale inhibitor, the adsorbent, the dodecyl dimethyl betaine and the coagulant aid, continuously preserving heat, stirring for 30-60min, and cooling to room temperature to obtain the composite water scavenger.

Description

Composite water-cleaning agent for oilfield sewage treatment and preparation method thereof Technical Field The application relates to the technical field of oilfield sewage treatment, in particular to a composite water scavenger for oilfield sewage treatment and a preparation method thereof. Background The oil field exploitation is a core industry for guaranteeing energy supply, a large amount of oil field sewage is inevitably generated in the whole flow of well drilling, oil extraction and gathering and transportation, the sewage is used as a byproduct of oil and gas exploitation, the water quantity is huge, the components are complex, the sewage belongs to typical high-difficulty industrial wastewater treatment, and the treatment effect is directly related to ecological environment safety and sustainable development of the oil field industry. The oilfield sewage contains not only oil substances such as suspension oil, emulsified oil and the like, but also high-concentration inorganic salts, suspended matters such as clay silt and the like, refractory organic matters and chemical additive residues, and if the oilfield sewage is not effectively treated and directly discharged or recycled, soil salinization and water hypoxia can be caused, stratum pores can be blocked, corrosion treatment equipment can be blocked, and the oilfield green development process is severely restricted. In order to realize harmless emission and recycling of oilfield sewage, a water scavenger is widely used as a core treatment agent, oil, suspended matters, partial organic matters and the like in the sewage are effectively removed through the functions of demulsification, flocculation, adsorption and the like, the concentration of sewage pollutants is reduced, and the index requirement of oilfield reinjection water or standard emission is met, so that the water scavenger is an indispensable key material in an oilfield sewage treatment system. At present, a plurality of related patents of water scavenger for oilfield sewage treatment are disclosed in the industry, and different types of technical schemes are formed to adapt to various sewage treatment demands. For example, the patent application document with publication number of CN113121812A discloses a water scavenger for oil field oily sewage treatment, and a preparation method and application thereof, wherein the water scavenger is prepared by stepwise reaction of dimethylamine aqueous solution, dodecyl dimethyl tertiary amine, epichlorohydrin and polyethylene polyamine, has the characteristics of lower viscosity and small dosage, is suitable for offshore oil field oily sewage treatment, and has the oil removal rate of 86% -95% when the oil field oily sewage with the oil content of 200-1500mg/L is treated. For another example, patent document CN114276549B discloses an anionic high-surface-activity organosilicon water scavenger and a preparation method thereof, and the prepared hyperbranched organosilicon polymer has a large amount of-NH 2 or/and-OH functional groups, has good water solubility and high surface activity, generates little floc, shows good clean water effect in polymer flooding oil extraction sewage treatment, and can effectively remove oil and suspended matter impurities in sewage. In addition, a plurality of water cleaning agents designed aiming at the conventional working conditions are also provided, and the water cleaning agents are respectively focused on optimization of different performance indexes such as demulsification efficiency, flocculation speed and the like, so that diversified technical choices are provided for oilfield sewage treatment. However, the conventional water-cleaning agent and the conventional water-cleaning agent in the industry are multi-adaptive to conventional working conditions, when sewage generated during middle and later periods of oil field exploitation, compact oil exploitation and pressure flowback fluid return is treated, the sewage has the characteristics of high salt and high oil content, the conventional water-cleaning agent has poor treatment effect on the sewage, and the problems of incomplete demulsification, poor flocculation effect and insufficient removal of oil and suspended matters are particularly manifested, and the treated effluent cannot meet the requirements of standard discharge or reinjection. The active components of the existing water-cleaning agent are single in structure, lack of salt resistance modification design, the high-salt environment can destroy the molecular charge balance and inhibition activity of the water-cleaning agent, the adsorption chelating capacity of the water-cleaning agent is insufficient, active functional groups are easily coated by salt ions and cannot fully react with oil drops and suspended matters, the treatment efficiency is reduced, and the water-cleaning agent is difficult to adapt to the increasingly complex sewage treatment requirements of oil fields, so that the developm