A nano water treatment agent, its preparation method and its application

Abstract

A nano water treatment agent, a preparation method thereof and an application thereof. The nano water treatment agent is composed of a small molecule polymer, water and a solvent; the solvent is coated by the small molecule polymer; the small molecule polymer is a polymer containing an amide bond formed by the reaction of an amino group at the end of a small molecule biomaterial with an acyl chloride in an amide condensation manner. The polymer has multiple hydrophilic groups, and the molecular formula of the polymer is R-CO-polypeptide-COOH; the small molecule biomaterial is a protein peptide with a molecular weight less than 5000 daltons. The oil removal rate of the nano water treatment agent is 99.21% - 99.77%, the sterilization rate is 97.7% - 100%, and the sulfur removal rate is 90% - 100%. The nano water treatment agent of the present invention adsorbs on the surface and interface of colloidal particles in oily sewage, penetrates a large number of microporous cell walls, displaces and destroys the stable oil-water interface, peels off impurities and settles, having remarkable demulsification and oil removal, sterilization and sulfur removal effects, and the method has low cost, simple operation and no secondary pollution.

Description

Technical Field

[0001] The present invention belongs to the technical field of oily sewage treatment, and particularly relates to a nano water treatment agent, a preparation method thereof, and an application thereof. Background Art

[0002] Oily sewage is an associated substance in the crude oil produced by oil fields. The treatment of oily sewage is an important part of the crude oil extraction process and has always been highly regarded. However, due to its inherent complexity, it remains an unsolved problem to date. With the increasingly strict environmental protection indicators, the technical requirements for oily sewage treatment are getting higher and higher. Because of the huge cost, for a long time, the treatment and utilization of oily sewage have been plaguing the production and development of oil fields. Therefore, reducing the water treatment cost and improving the water treatment effect are of great significance.

[0003] At present, the oily sewage treatment process in oil field gathering stations is divided into primary sedimentation, oil removal, coagulation, and secondary sedimentation. The commonly used agents are water purifying agents, flocculants, desulfurizing agents, bactericides, etc. These agents are all single-functional agents. With a small dosage, the sewage treatment effect is poor; with a large dosage, the cost is high. There are many factors affecting the oily sewage treatment in gathering stations. The pour point, viscosity, heavy components, asphaltenes, etc. of the crude oil itself in the settling tank, as well as the temperature, oil production aids, and the liquid situation from upstream sites during the production and treatment process can all affect the generation rate and treatment difficulty of oily sewage. Through analysis, it is found that the higher the asphaltene content of the crude oil entering the gathering station, the greater the strength of the oil-water interface. The heavy components prevent the water droplets from flocculating and settling, resulting in a more stable emulsion and greater treatment difficulty. In addition, the impurity content in the oily sewage also increases the treatment difficulty because the impurities, naphthenic acid, and microcrystalline paraffin mixed in the oily sewage belong to natural emulsifiers, making the oil-water two-phase system form a network structure film.

[0004] Gao Baoyu et al. compounded the water purifying agent polyaluminum chloride and the flocculant polyacrylamide to treat the sewage in Tuosi of Shengli Oilfield. The results showed that the higher the dosages of the water purifying agent and the flocculant, the higher the oil removal effect and the removal rate of suspended solids. The average oil removal rate was 90%, but the removal rate of suspended solids was only 50.5% - 64.1%. Shao Qing et al. conducted laboratory research on the dilute oil sewage in the No. 1 Oil Production Plant of Karamay, Xinjiang, using the TX-107 series of organic polymer demulsifying flocculants. The results showed that the average oil content after treatment with this agent was 26.7 mg / L, which was 100.54 mg / L lower than the oil content of the effluent after treatment with the original flocculant, but still did not meet the standards. Ma Hongzhu et al. studied the sewage in Changqing Oilfield and used the Z-10 multifunctional agent synthesized in the laboratory to comprehensively treat the oily sewage, completing the processes of flocculation, scale inhibition, corrosion prevention, and sterilization in one step, simplifying the sewage treatment process and reducing the treatment cost, but it is not applicable to the treatment of high-oil-content and high-sulfur sewage.

[0005] In summary, the development of water treatment agents has been very mature, which can solve most problems. However, there is an urgent need for multifunctional water treatment agents that can reduce costs and increase efficiency to solve the problems of large water quality fluctuations at the combined station site, difficult treatment with conventional agents, and high costs. Summary of the Invention

[0006] The purpose of the present invention is to provide a nano water treatment agent, a preparation method thereof, and an application thereof. A nano water treatment agent is prepared by compounding a small molecule polymer, water, and a solvent. In this nano water treatment agent, the small molecule polymer is coated around the solvent droplets, adsorbed at the oil-water interface of oily sewage, penetrates through a large number of microporous cell walls, displaces and destroys the stable oil-water interface in the oily sewage, peels off impurities and settles them, and has remarkable demulsification and oil removal, bactericidal and sulfur removal effects.

[0007] The technical solution adopted by the present invention is as follows:

[0008] A nano water treatment agent is composed of a small molecule polymer, water, and a solvent; the solvent is coated by the small molecule polymer;

[0009] The small molecule polymer is a polymer containing amide bonds formed by the reaction of the amino group at the end of a small molecule biomaterial with acyl chloride (C 12 ~C 18 ) in an amide condensation manner. This polymer has multiple hydrophilic groups, and the polymer molecular formula is R-CO-polypeptide-COOH;

[0010] The small molecule biomaterial is a protein peptide with a molecular weight less than 5000 daltons.

[0011] Furthermore, the mass ratio of the small molecule polymer to the solvent is 0.5 to 4:1.

[0012] Furthermore, the water content in the nano water treatment agent is 15 to 35 wt%.

[0013] Furthermore, the water content in the nano water treatment agent is 20 to 33 wt%.

[0014] Furthermore, the solvent is selected from at least one of ethyl acetate, light white oil, and petroleum ether.

[0015] Furthermore, the content of the small molecule polymer in the nano water treatment agent is 20 to 70 wt%.

[0016] The preparation method of the nano water treatment agent is to mix the small molecule polymer and water and stir evenly, then add the solvent and continue to stir to obtain the finished product; the stirring and mixing conditions are: temperature 25°C, time 20 to 30 min.

[0017] The method for treating oily sewage (demulsifying and removing oil, sterilizing and desulfurizing) with the described nano water treatment agent is to add the nano water treatment agent to the oily sewage, stir for 30 - 60 s, and then let it stand still to wait for layering and precipitation; the dosage of the nano water treatment agent is 10 - 40 ppm.

[0018] Advantages of the present invention:

[0019] The present invention prepares a self-made small molecule polymer, coats the solvent with the small molecule polymer to form a nano-sized "core-shell" structure, and obtains a nano water treatment agent with ultra-low interfacial tension, good demulsifying and oil-removing ability, and sterilizing and desulfurizing ability. Utilizing its nano-sized advantage, it adsorbs on the oil-water interface and colloid surface of the oily sewage, penetrates a large number of microporous cell walls, displaces and destroys the stable oil-water interface of the oily sewage and releases the solvent, peels off impurities and precipitates, separates the oil and impurities in the water, has remarkable demulsifying and oil-removing, sterilizing and desulfurizing effects, and this method has low cost, simple operation, and no secondary pollution. The oil removal rate of this nano water treatment agent is 99.21 - 99.77%, the sterilization rate is 97.7% - 100%, and the desulfurization rate is 90% - 100%. Description of the drawings

[0020] Figure 1 It is the infrared spectrogram of the self-made small molecule polymer. The characteristic peak of the amide group is 1650 cm -1 is the carbonyl peak, 1608 cm -1 , 1407 cm -1 is the C-N stretching vibration peak, 1280 cm -1 is the C-N stretching vibration + NH bending vibration, 721 cm -1 is the out-of-plane vibration peak of NH2. Detailed implementation manners

[0021] The oily sewage comes from a certain joint station of the Yanchang Oilfield. The demulsifying and oil-removing, sterilizing and desulfurizing effects of the nano water treatment agent are characterized by testing the oil content, bacterial count, and sulfide content in the water before and after treatment. The testing methods are as follows:

[0022] (1) Oil content analysis steps

[0023] a) Take 100 mL of the water sample in a separating funnel, add 3 mL of 1 + 1 hydrochloric acid and 20 mL of petroleum ether, and perform extraction.

[0024] b) Pour the separated upper liquid into a cuvette and add petroleum ether dropwise to 50 mL. Measure the absorbance of the oil sample at a wavelength of 430 nm, and measure the absorbance with petroleum ether as the reference.

[0025] c) Substitute the absorbance value into the standard curve formula to calculate the oil content.

[0026] (2) Bacterial quantity analysis steps

[0027] a) Arrange the test bottles in a group and number them sequentially.

[0028] b) Before sampling, let it flow smoothly at a flow rate of 5 L / min to 6 L / min for 3 min, then sample. Use a sterile syringe to take 1.0 ml of water sample and inject it into bottle No. 1, and shake well.

[0029] c) Use another sterile syringe to take 1.0 ml of water sample from bottle No. 1 and inject it into bottle No. 2, and shake well.

[0030] d) Replace the sterile syringe again, take 1.0 ml of water sample from bottle No. 2 and inject it into bottle No. 3, and shake well.

[0031] e) And so on until the last bottle is diluted. Determine the number of dilution bottles according to the bacterial content, generally diluted to bottle No. 7.

[0032] f) Put the above test bottles into a constant temperature incubator for cultivation, control the temperature within ±5°C of the on-site water temperature, and read the value after 7 d.

[0033] (3) Sulfide analysis steps

[0034] a) Take a 50 mL volume of water sample, add 4 mL of 1 mol / L zinc acetate and 4 mL of 1 mol / L sodium hydroxide, shake well, and precipitate.

[0035] b) Add 10 mL of 0.1 mol / L iodine solution, add 5 mL of 1+1 hydrochloric acid, and let it stand in the dark for 5 min.

[0036] c) Add 1 mL of starch indicator, titrate the excess iodine with 0.1005 mol / L sodium thiosulfate until the light blue color disappears, and record VNa2S2O3.

[0037] d) Do a blank titration while dripping the water sample, and record the consumption V0.

[0038] e) Calculate

[0039]

[0040] C Na2S2O3 -Concentration of sodium thiosulfate standard solution, mol / L

[0041] V0-Consumption of sodium thiosulfate standard solution when measuring the blank sample, mL

[0042] V1-Consumption of sodium thiosulfate standard solution when measuring the water sample, mL

[0043] Vwater sample-Volume of water sample, mL

[0044] The oily sewage taken was tested according to the above method, and the results were as follows: the initial oil content rate of the tested oily sewage was 1320 ppm, the number of bacteria TGB was 2.5*10 3 , and the sulfide content was 51.55 mg / L.

[0045] The molecular formula of the small molecule polymer used in Examples 1 to 6 is C 17 H 35 -CO-polypeptide-COOH. The infrared spectrogram of the small molecule polymer is as Figure 1 shown; among them, the small molecule biomaterial is a protein peptide with a molecular weight of 3000 daltons.

[0046] Example 1

[0047] (1) Add 5 g of the small molecule polymer to 5 mL of clear water. After stirring evenly, add 5 g of ethyl acetate and 5 g of petroleum ether, and stir at room temperature for 20 min to obtain a nano water treatment agent;

[0048] (2) Add 10 ppm of the nano water treatment agent to the oily sewage;

[0049] (3) Stir for 30 s and let it stand for sedimentation and stratification;

[0050] The mass ratio of the small molecule polymer to the solvent is 1:2; after treatment, the oil content is 5.22 ppm, the number of bacteria TGB is 57.5, the sulfide content is 5.16 mg / L, the oil removal rate is 99.6%, the sterilization rate is 97.7%, and the sulfur removal rate is 90%.

[0051] Example 2

[0052] (1) Add 5 g of the small molecule polymer to 5 mL of clear water. After stirring evenly, add 5 g of ethyl acetate, and stir at room temperature for 30 min to obtain a nano water treatment agent;

[0053] (2) Add 20 ppm of the nano water treatment agent to the oily sewage;

[0054] (3) Stir for 40 s and let it stand for sedimentation and stratification;

[0055] The mass of the small molecule polymer to the solvent is 1:1; after treatment, the oil content is 6.705 ppm, the number of bacteria TGB is 0, the sulfide content is 5.16 mg / L, the oil removal rate is 99.49%, the sterilization rate is 100%, and the sulfur removal rate is 90%.

[0056] Example 3

[0057] (1) Add 10 g of the small molecule polymer to 5 mL of clear water. After stirring evenly, add 5 g of petroleum ether, and stir at room temperature for 30 min to obtain a nano water treatment agent;

[0058] (2) Add 30 ppm of the nano water treatment agent to the oily sewage;

[0059] (3) Stir for 40 s and let it stand for sedimentation and stratification;

[0060] The mass ratio of the small molecule polymer to the solvent is 2:1; the oil content after treatment is 2.98 ppm, the number of bacteria TGB is 0, the sulfide content is 1.55 mg / L, the oil removal rate is 99.77%, the sterilization rate is 100%, and the desulfurization rate is 97%.

[0061] Example 4

[0062] (1) Add 15 g of the small molecule polymer to 5 mL of clear water, stir evenly, then add 5 g of light white oil, and stir at room temperature for 30 min to obtain the nano water treatment agent;

[0063] (2) Add 40 ppm of the nano water treatment agent to the oily sewage;

[0064] (3) Stir for 60 s and let it stand for sedimentation and stratification;

[0065] The mass ratio of the small molecule polymer to the solvent is 3:1; the oil content after treatment is 5.96 ppm, the number of bacteria TGB is 0, the sulfide content is 0, the oil removal rate is 99.55%, the sterilization rate is 100%, and the desulfurization rate is 100%.

[0066] Example 5

[0067] (1) Add 10 g of the small molecule polymer to 5 mL of clear water, stir evenly, then add 5 g of light white oil and 5 g of ethyl acetate, and stir at room temperature for 30 min to obtain the nano water treatment agent;

[0068] (2) Add 20 ppm of the nano water treatment agent to the oily sewage;

[0069] (3) Stir for 40 s and let it stand for sedimentation and stratification;

[0070] The mass ratio of the small molecule polymer to the solvent is 1:1; the oil content after treatment is 10.43 ppm, the number of bacteria TGB is 0, the sulfide content is 0, the oil removal rate is 99.21%, the sterilization rate is 100%, and the desulfurization rate is 100%.

[0071] Example 6

[0072] (1) Add 20 g of the small molecule polymer to 5 mL of clear water, stir evenly, then add 5 g of petroleum ether, and stir at room temperature for 25 min to obtain the nano water treatment agent;

[0073] (2) Add 20 ppm of the nano water treatment agent to the oily sewage;

[0074] (3) Stir for 60 s and let it stand for sedimentation and layering;

[0075] The mass ratio of the small molecule polymer to the solvent is 4:1; the oil content after treatment is 2.98 ppm, the number of bacteria TGB is 0, the sulfide content is 0, the oil removal rate is 99.77%, the sterilization rate is 100%, and the desulfurization rate is 100%.

Claims

1. A nano water treatment agent, characterized in that It is composed of a small molecule polymer, water and a solvent; the solvent is coated by the small molecule polymer, the small molecule polymer is coated around the solvent droplets, adsorbed at the oil-water interface of oily sewage, penetrates a large number of microporous cell walls, displaces and destroys the stable oil-water interface in the oily sewage, and peels off impurities for sedimentation; the solvent is selected from at least one of ethyl acetate, light white oil, and petroleum ether; The small molecule polymer is a polymer containing amide bonds formed by the reaction of the amino group at the end of a small molecule biomaterial with acyl chloride in an amide condensation manner. This polymer has multiple hydrophilic groups, and the polymer molecular formula is R-CO-polypeptide-COOH; the small molecule biomaterial is a protein peptide with a molecular weight less than 5000 daltons. The mass ratio of the small molecule polymer to the solvent is 0.5-4:1, and the content of the small molecule polymer in the nano water treatment agent is 20-70 wt%.

2. The nano water treatment agent according to claim 1, characterized in that The water content in the nano water treatment agent is 15-35 wt%.

3. The nano water treatment agent according to claim 1, wherein, The water content in the nano water treatment agent is 20-33 wt%.

4. The preparation method of any one of the nano water treatment agents according to claims 1 to 3, characterized in that, Mix the small molecule polymer and water evenly by stirring, and then add the solvent and continue stirring to obtain the finished product; the stirring and mixing conditions are: temperature 25°C, time 20-30 min.

5. A method for treating oily sewage with any one of the nano water treatment agents described in claims 1 to 3, characterized in that, It is to add the nano water treatment agent to the oily sewage, stir for 30-60 s, and then let it stand to wait for stratification and precipitation; the dosage of the nano water treatment agent is 10-40 ppm.

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