A cellulose ether-based scale inhibitor and a method for preparing the same

Abstract

The present application relates to the technical field of scale inhibitor, and particularly discloses a scale inhibitor based on cellulose ether and a preparation method thereof; comprising the following operation steps: S1: grafting 5-amino lysine, 2,4-diamino-6-vinyl-S-triazine and cellulose ether to obtain modified cellulose ether; S2: compounding modified tannic acid and the modified cellulose ether through click reaction to obtain cellulose ether derivative; and S3: uniformly mixing the cellulose ether derivative, polyaspartic acid / castor oil acid, EDTA and a film forming agent to obtain the scale inhibitor.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of scale inhibitors, in particular to a cellulose ether-based scale inhibitor and a preparation method thereof. BACKGROUND

[0002] Heat exchange equipment is a commonly used heat exchange device in industrial thermal systems. During long-term operation, crystallization fouling problems of varying degrees occur on the heat exchange surface. The formation of crystallization fouling leads to a significant decrease in heat exchange effect and corrosion of the heat exchange surface, resulting in perforation of the heat exchange equipment and causing huge problems in terms of economic losses and safe operation of the equipment.

[0003] In the prior art, cellulose ether derivatives are often used as scale inhibitors to solve the problem of scale inhibition. Although cellulose ether derivatives are widely available, non-toxic and easily degradable, their carboxyl and hydroxyl functional groups can complex with metal cations and have the potential to be used as green and environmentally friendly scale inhibitors, but their scale removal ability is limited. Moreover, if the equipment surface has been left with corrosion marks due to long-term fouling deposition, the subsequent accumulation of fouling will actually promote corrosion of the equipment surface, and the low corrosion inhibition of cellulose ether derivatives cannot solve this problem.

[0004] In view of the above, it is of great significance to prepare a cellulose ether-based scale inhibitor. SUMMARY

[0005] The present application aims to provide a cellulose ether-based scale inhibitor and a preparation method thereof to solve the problems raised in the background.

[0006] A preparation method of a cellulose ether-based scale inhibitor, comprising the following operation steps:

[0007] S1: grafting 5-amino lysine, 2,4-diamino-6-vinyl-S-triazine and cellulose ether to obtain modified cellulose ether;

[0008] S2: compounding modified tannic acid and modified cellulose ether by click reaction to obtain cellulose ether derivatives;

[0009] S3: uniformly mixing cellulose ether derivatives, polyaspartic acid / castor oil acid, EDTA and film-forming agent to obtain a scale inhibitor.

[0010] More preferably, the raw materials of the scale inhibitor include the following components: 60-70 parts by weight of cellulose derivatives, 15-20 parts by weight of polyaspartic acid / castor oil acid, 3-5 parts by weight of EDTA, and 1-1.5 parts by weight of film-forming agent.

[0011] More preferably, the preparation method of the modified cellulose ether is as follows: 5-amino lysine and 2,4-diamino-6-vinyl-S-triazine are added into deionized water to uniformly mix to obtain a mixed solution A; cellulose ether and carbonyl diimidazole are added into tetrahydrofuran to uniformly mix, and the mixed solution A is added, and the mixture is reacted at 30-40℃ for 12-16 hours, and then purified to obtain the modified cellulose ether.

[0012] More preferably, the cellulose ether comprises 2-hydroxyethyl ether cellulose and hydroxyethyl methyl cellulose in a mass ratio of 1:(0.1-0.3).

[0013] More preferably, the raw material of the modified cellulose ether comprises the following components: 9-13 parts of 5-amino lysine, 8-10 parts of 2,4-diamino-6-vinyl-S-triazine, 5-6 parts of carbonyl diimidazole, 20-30 parts of cellulose ether, and 50-70 parts of tetrahydrofuran.

[0014] More preferably, the preparation method of the modified tannic acid is as follows: (1) tannic acid is added into pyridine to uniformly mix at 35-45℃, and methyl tetrahydrophthalic anhydride is added, and the mixture is reacted at 95-100℃ for 12-20 hours after being reacted at 1-2 hours, and then purified to obtain carboxylated tannic acid; (2) carboxylated tannic acid and cysteine are added into deionized water to react at 110-124℃ for 2-3 hours, and then the pH is adjusted to 10 to obtain the modified tannic acid.

[0015] More preferably, the raw material of the carboxylated tannic acid comprises the following components: 4-6 parts of tannic acid, 10-20 parts of methyl tetrahydrophthalic anhydride, and 45-55 parts of pyridine; and the mass ratio of cysteine to carboxylated tannic acid is (0.008-0.012):1.

[0016] More preferably, the preparation method of the cellulose ether derivative is as follows: the modified tannic acid, the modified cellulose ether, and azobisisobutyronitrile are uniformly mixed in tetrahydrofuran, and the mixture is irradiated under ultraviolet light for 2-2.5 hours, and then purified to obtain the cellulose ether derivative.

[0017] More preferably, the raw material of the cellulose ether derivative comprises the following components: 0.065-0.15 parts of the modified tannic acid, 0.27-0.35 parts of the cellulose ether derivative, 0.002-0.003 parts of AIBN, and 18-25 parts of tetrahydrofuran; and the process conditions of ultraviolet light irradiation are as follows: the emission wavelength is 365nm, and the light intensity is 80-110mW / cm 2 .

[0018] The more optimized preparation method of the polyaspartic acid / castor oil acid comprises the following steps: uniformly mixing castor oil acid, thio glycerol and 2-hydroxy-2-methyl-1-phenyl-1-propanone, irradiating under ultraviolet light with light intensity of 50-60 mW / cm 2 for 1.5-2 hours to obtain modified castor oil acid; adding polyaspartic acid into ethanol, adding the modified castor oil acid, and reacting at 75-85 DEG C for 4-5 hours, and continuously reacting for 8-10 hours after the temperature is reduced to room temperature to obtain polyaspartic acid / castor oil acid.

[0019] The more optimized raw material of the modified castor oil acid comprises the following components in parts by weight: 1-1.2 parts of castor oil acid, 2-2.5 parts of thio glycerol, and 0.015-0.02 parts of 2-hydroxy-2-methyl-1-phenyl-1-propanone; the mass ratio of polyaspartic acid to modified castor oil acid is (0.4-0.6):1.

[0020] In the scheme, carbonyl diimidazole is used as an activator, 5-amino lysine and 2,4-diamino-6-vinyl-S-triazine are reacted with cellulose ether to obtain modified cellulose ether.

[0021] The cellulose ether in the application comprises 2-hydroxyethyl ether cellulose with viscosity of 1500 mPa.s and hydroxyethyl methyl cellulose with viscosity of 12000 mPa.s; wherein, the high viscosity cellulose ether and the low viscosity cellulose ether are uniformly mixed, the better thickening property of the high viscosity cellulose ether and the better permeability of the low viscosity cellulose ether are combined, so that the existing dirt can be better penetrated and dispersed while preventing particle deposition and fouling.

[0022] 2,4-diamino-6-vinyl-S-triazine has multiple amino groups and heteroatoms on the triazine ring, and these functional groups enable it to form a complex with metal ions. In the modified cellulose ether, it can form a complex with metal ions such as calcium and magnesium in water, so as to prevent these metal ions from depositing on the surface of pipes and equipment and reduce the formation of water scale.

[0023] 5-amino lysine is an amino acid containing amino and carboxyl groups, which can chemically react with the hydroxyl reaction sites in the cellulose ether molecules, so as to improve the ability of the cellulose ether to interact with water and improve its dispersibility and solubility in water. Amino acid is a good corrosion inhibitor, but it is high in economic cost if directly used as a corrosion inhibitor, so grafting it to the cellulose ether can reduce the economic cost and make the cellulose ether have certain corrosion resistance.

[0024] Although the cellulose ether is modified, the content of hydroxyl group on the cellulose ether is reduced, thereby affecting the efficiency of scale removal, in order to improve the scale removal effect and improve the corrosion inhibition of the scale remover, the carboxyl group is introduced into the tannic acid, and then the mercapto group is introduced into the carboxylated tannic acid through cysteine, so that the modified tannic acid is obtained; the modified tannic acid and the modified cellulose ether are connected through a covalent bond, which can increase the interaction force between them, improve the dispersibility and stability of the modified cellulose ether in water.

[0025] The modified tannic acid and the modified cellulose ether are connected through a covalent bond, which can increase the interaction force between them, improve the dispersibility and stability of the modified cellulose ether in water.

[0026] Tannic acid is a kind of natural product, when tannic acid contacts with metal surface, the carboxyl and hydroxyl group of tannic acid form complex or chemical adsorption with the surface, so as to prevent the metal from contacting with oxygen, water or other corrosion medium in the surrounding environment, and slow down or prevent the corrosion of the metal. The introduction of multiple carboxyl groups in tannic acid can enhance the complexing ability of tannic acid with metal ions in water, thereby reducing the deposition of metal ions on the surface of pipes and equipment, preventing the formation of scale, and maintaining the normal operation of the equipment.

[0027] In order to improve the scale inhibition effect and corrosion inhibition of the cellulose ether derivative, and expand the application range of the scale inhibitor, polyaspartic acid / castor oil acid is added to the scale remover.

[0028] Polyaspartic acid is a natural polypeptide polymer, which can not only form complex or other bonding with calcium, magnesium and other ions in water to prevent the deposition of these ions on the surface of pipes and equipment, but also can occur on the surface of carbon steel or inhibitor interface, thereby achieving the effect of corrosion inhibition.

[0029] Castor oil acid has certain surface activity, which can form a uniform lubricating film on the surface of pipes and equipment, reduce the adhesion of scale, and prolong the service life of the equipment; through modification by thio-glycerol, multiple hydroxyl groups are introduced into the castor oil acid, thereby preventing the deposition of metal ions on the surface of pipes and equipment.

[0030] The modification of polyaspartic acid with castor oil acid can enhance the compatibility between them, which is helpful to improve the dispersibility and stability of the modified polyaspartic acid in water, thereby enhancing the scale inhibition effect. It can also increase the complexing ability between polyaspartic acid and metal ions, further improve the scale inhibition effect, and reduce the deposition of metal ions on the surface of pipes and equipment, thereby reducing the corrosion rate of the metal surface and indirectly improving the corrosion inhibition.

[0031] EDTA as part of the scale inhibitor can improve the water treatment effect, so that the metal ions in the water are more easily removed, and the water purification efficiency and quality are improved. EDTA itself has good chemical stability and controllability, and can stably play its role of complexing metal ions under different water quality conditions, maintain the persistent effect and reliability of the scale inhibitor; so that the scale inhibitor effectively reduces the scale accumulation on the surface of pipelines, equipment and heat exchangers, and reduces the problems of pipeline blockage and heat transfer efficiency reduction. DETAILED DESCRIPTION

[0032] The following is a preferred embodiment of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all. For ordinary skilled in the art, without departing from the principles of the embodiments of the present application, all other embodiments obtained by ordinary skilled in the art without creative labor belong to the scope of protection of the present application.

[0033] In the following specific embodiment, parts are parts by weight. In this embodiment, it should be noted that there is no special restriction on the purchase manufacturer of all raw materials involved in the present application, which exemplarily includes: the CAS number of 5-amino lysine is 98961-95-6, the CAS number of 2,4-diamino-6-vinyl-S-triazine is 3194-70-5, the viscosity of 2-hydroxyethyl ether cellulose is 1500 mpa.s, the viscosity of hydroxyethyl methyl cellulose is 12000 mPa.s, the article number of tannic acid is T25393, the CAS number of methyl tetrahydrophthalic anhydride is 19438-64-3, the CAS number of cysteine is 52-90-4, the model of ricinoleic acid is 190KG / iron drum, the CAS number of thioglycerol is 96-27-5, the article number of polyaspartic acid is T25164, the CAS number of azobisisobutyronitrile is 78-67-1, the CAS number of EDTA is 60-00-4, and the CAS number of 2-hydroxy-2-methyl-1-phenyl-1-propanone (HMPP) is 7473-98-5.

[0034] The preparation method of modified tannic acid is: (1) 5 parts of tannic acid are added to 45 parts of pyridine and uniformly mixed at 35℃, 15 parts of methyl tetrahydrophthalic anhydride are added, and the reaction is continued for 1.2 hours, then the temperature is raised to 95℃ and the reaction is continued for 12 hours, and then purified to obtain carboxylated tannic acid; (2) carboxylated tannic acid and cysteine are added to deionized water, and reacted at 110℃ for 2 hours, and the pH is adjusted to 10 to obtain modified tannic acid; the mass ratio of cysteine to carboxylated tannic acid is 0.008:1.

[0035] Example 1: A preparation method of a scale inhibitor based on cellulose ether, comprising the following operation steps:

[0036] S1: (1) 9 parts of 5-amino lysine and 10 parts of 2,4-diamino-6-vinyl-S-triazine are added to deionized water to obtain a mixed solution A; 25 parts of cellulose ether and 6 parts of carbonyl diimidazole are added to 50 parts of tetrahydrofuran to obtain a mixed solution B; the mixed solution A is added to the mixed solution B, and the mixture is reacted at 35°C for 12 hours to obtain a modified cellulose ether; the cellulose ether comprises 2-hydroxyethyl ether cellulose and hydroxyethyl methyl cellulose at a mass ratio of 1:0.25;

[0037] (2) 1 part of ricinoleic acid, 2.2 parts of thioglycerol, and 0.015 parts of HMPP are uniformly mixed, and irradiated under ultraviolet light with an emission wavelength of 365 nm and an intensity of 50 mW / cm 2 for 2 hours to obtain a modified ricinoleic acid; polyaspartic acid is added to ethanol, and the modified ricinoleic acid is added to the ethanol, and the mixture is reacted at 75°C for 4 hours, and then the temperature is lowered to room temperature and the reaction is continued for 8 hours to obtain polyaspartic acid / ricinoleic acid; the mass ratio of polyaspartic acid to modified ricinoleic acid is 0.4:1;

[0038] S2: 0.08 parts of modified tannic acid, 0.32 parts of modified cellulose ether, and 0.002 parts of azobisisobutyronitrile are uniformly mixed in tetrahydrofuran, and irradiated under ultraviolet light with an emission wavelength of 365 nm and an intensity of 100 mW / cm 2 for 2 hours, and then purified to obtain a cellulose ether derivative;

[0039] S3: 60 parts of the cellulose ether derivative, 15 parts of polyaspartic acid / ricinoleic acid, 3 parts of EDTA, and 1 part of a film-forming agent are mixed to obtain a scale inhibitor.

[0040] Example 2: A preparation method of a cellulose ether-based scale inhibitor, comprising the following operation steps:

[0041] S1: (1) 9 parts of 5-amino lysine and 10 parts of 2,4-diamino-6-vinyl-S-triazine are added to deionized water to obtain a mixed solution A; 25 parts of cellulose ether and 6 parts of carbonyl diimidazole are added to 50 parts of tetrahydrofuran to obtain a mixed solution B; the mixed solution A is added to the mixed solution B, and the mixture is reacted at 35°C for 12 hours to obtain a modified cellulose ether; the cellulose ether comprises 2-hydroxyethyl ether cellulose and hydroxyethyl methyl cellulose at a mass ratio of 1:0.25;

[0042] (2) 1 part of ricinoleic acid, 2.2 parts of thioglycerol, and 0.015 parts of HMPP are uniformly mixed, and irradiated under ultraviolet light with an intensity of 50 mW / cm 2 for 2 hours to obtain a modified ricinoleic acid; polyaspartic acid is added to ethanol, and the modified ricinoleic acid is added to the ethanol, and the mixture is reacted at 75°C for 4 hours, and then the temperature is lowered to room temperature and the reaction is continued for 8 hours to obtain polyaspartic acid / ricinoleic acid; the mass ratio of polyaspartic acid to modified ricinoleic acid is 0.4:1;

[0043] S2: 0.08 parts of modified tannin acid, 0.32 parts of modified cellulose ether, 0.002 parts of azobisisobutyronitrile were uniformly mixed in tetrahydrofuran, irradiated under ultraviolet light with an emission wavelength of 365 nm and an intensity of 100 mW / cm 2 for 2 hours, purified to obtain a cellulose ether derivative;

[0044] S3: 65 parts of cellulose ether derivative, 15 parts of polyaspartic acid / castor oil acid, 3.5 parts of EDTA, 1.2 parts of film-forming agent were mixed to obtain a scale inhibitor.

[0045] Example 3: A method for preparing a cellulose ether-based scale inhibitor, comprising the following operation steps:

[0046] S1: (1) 9 parts of 5-amino lysine and 10 parts of 2,4-diamino-6-vinyl-S-triazine were uniformly mixed in deionized water to obtain a mixed solution A; 25 parts of cellulose ether and 6 parts of carbonyl diimidazole were uniformly mixed in 50 parts of tetrahydrofuran, and the mixed solution A was added, and reacted at 35°C for 12 hours, and purified to obtain a modified cellulose ether; the cellulose ether comprises 2-hydroxyethyl ether cellulose and hydroxyethyl methyl cellulose with a mass ratio of 1:0.25;

[0047] (2) 1 part of castor oil acid, 2.2 parts of thio glycerol, and 0.015 parts of HMPP were uniformly mixed, and irradiated under ultraviolet light with an intensity of 50 mW / cm 2 for 2 hours to obtain a modified castor oil acid; polyaspartic acid was added to ethanol, and the modified castor oil acid was added, and reacted at 75°C for 4 hours, and then the temperature was lowered to room temperature and the reaction was continued for 8 hours to obtain polyaspartic acid / castor oil acid; the mass ratio of polyaspartic acid to modified castor oil acid is 0.4:1;

[0048] S2: 0.08 parts of modified tannin acid, 0.32 parts of modified cellulose ether, 0.002 parts of azobisisobutyronitrile were uniformly mixed in tetrahydrofuran, irradiated under ultraviolet light with an emission wavelength of 365 nm and an intensity of 100 mW / cm 2 for 2 hours, purified to obtain a cellulose ether derivative;

[0049] S3: 65 parts of cellulose ether derivative, 15 parts of polyaspartic acid / castor oil acid, 3.5 parts of EDTA, 1.2 parts of film-forming agent were mixed to obtain a scale inhibitor.

[0050] Based on Example 2, the following control experiments were carried out, specifically Comparative Examples 1-4, as follows:

[0051] Comparative Example 1 is based on Example 2, and directly introduces cellulose ether.

[0052] S1: (1) Cellulose ethers include 2-hydroxyethyl ether cellulose and hydroxyethyl methyl cellulose in a mass ratio of 1:0.25;

[0053] (2) Mix 1 part ricinoleic acid, 2.2 parts thioglycerol, and 0.015 parts HMPP evenly at 50 mW / cm 2 Modified ricinoleic acid was obtained by irradiating the sample with ultraviolet light for 2 hours. Polyaspartic acid was added to ethanol, followed by the modified ricinoleic acid. The mixture was reacted at 75°C for 4 hours, and then the temperature was lowered to room temperature and the reaction was continued for 8 hours to obtain polyaspartic acid / ricinoleic acid. The mass ratio of polyaspartic acid to modified ricinoleic acid was 0.4:1.

[0054] S2: 0.08 parts modified tannic acid, 0.32 parts modified cellulose ether, and 0.002 parts azobisisobutyronitrile are uniformly mixed in tetrahydrofuran. The mixture is then subjected to an emission wavelength of 365 nm and a light intensity of 100 mW / cm². 2 Irradiate with ultraviolet light for 2 hours, then purify to obtain cellulose ether derivatives;

[0055] S3: A scale inhibitor is obtained by mixing 65 parts of cellulose ether, 15 parts of polyaspartic acid / ricinoleic acid, 3.5 parts of EDTA, and 1.2 parts of film-forming agent.

[0056] Comparative Example 2 is based on Example 2, in which a high molecular weight cellulose ether is introduced alone into the cellulose ether.

[0057] S1: (1) Add 9 parts of 5-aminolysine and 10 parts of 2,4-diamino-6-vinyl-S-triazine to deionized water and mix evenly to obtain mixed solution A; add 25 parts of cellulose ether and 6 parts of carbonyl diimidazole to 50 parts of tetrahydrofuran and mix evenly, add mixed solution A, react at 35°C for 12 hours, purify, and obtain modified cellulose ether; the cellulose ether includes 2-hydroxyethyl ether cellulose and hydroxyethyl methyl cellulose in a mass ratio of 1:0.25;

[0058] (2) Mix 1 part ricinoleic acid, 2.2 parts thioglycerol and 0.015 parts HMPP evenly and irradiate under ultraviolet light at 50 mW / cm2 for 2 hours to obtain modified ricinoleic acid; add polyaspartic acid to ethanol, add modified ricinoleic acid, react at 75℃ for 4 hours, and continue to react for 8 hours after cooling to room temperature to obtain polyaspartic acid / ricinoleic acid; the mass ratio of polyaspartic acid to modified ricinoleic acid is 0.4:1;

[0059] S2: 0.08 parts modified tannic acid, 0.32 parts modified cellulose ether, and 0.002 parts azobisisobutyronitrile are uniformly mixed in tetrahydrofuran. The mixture is then subjected to an emission wavelength of 365 nm and a light intensity of 100 mW / cm². 2 Irradiate with ultraviolet light for 2 hours, then purify to obtain cellulose ether derivatives;

[0060] S3: 65 parts of cellulose ether derivative, 15 parts of polyaspartic acid / castor oil acid, 3.5 parts of EDTA, 1.2 parts of film former are mixed to obtain the scale inhibitor.

[0061] Comparative Example 3 is based on Example 2 without the introduction of tannic acid.

[0062] S1: (1) 9 parts of 5-amino lysine and 10 parts of 2,4-diamino-6-vinyl-S-triazine are added to deionized water and uniformly mixed to obtain a mixed solution A; 25 parts of cellulose ether and 6 parts of carbonyl diimidazole are added to 50 parts of tetrahydrofuran and uniformly mixed, and the mixed solution A is added, and reacted at 35°C for 12 hours, purified to obtain a modified cellulose ether; the cellulose ether includes 2-hydroxyethyl ether cellulose and hydroxyethyl methyl cellulose with a mass ratio of 1:0.25;

[0063] (2) 1 part of castor oil acid, 2.2 parts of thioglycerol, and 0.015 parts of HMPP are uniformly mixed, and irradiated under ultraviolet light with an emission wavelength of 365 nm and an intensity of 100 mW / cm2for 2 hours to obtain a modified castor oil acid; polyaspartic acid is added to ethanol, and the modified castor oil acid is added, and reacted at 75°C for 4 hours, and after the temperature is reduced to room temperature, the reaction is continued for 8 hours to obtain polyaspartic acid / castor oil acid; the mass ratio of polyaspartic acid to modified castor oil acid is 0.4:1; 2

[0064] S2: 65 parts of modified cellulose ether, 15 parts of polyaspartic acid / castor oil acid, 3.5 parts of EDTA, and 1.2 parts of film former are mixed to obtain the scale inhibitor.

[0065] Comparative Example 4 is based on Example 2 without the addition of polyaspartic acid / castor oil acid.

[0066] S1: (1) 9 parts of 5-amino lysine and 10 parts of 2,4-diamino-6-vinyl-S-triazine are added to deionized water and uniformly mixed to obtain a mixed solution A; 25 parts of cellulose ether and 6 parts of carbonyl diimidazole are added to 50 parts of tetrahydrofuran and uniformly mixed, and the mixed solution A is added, and reacted at 35°C for 12 hours, purified to obtain a modified cellulose ether; the cellulose ether includes 2-hydroxyethyl ether cellulose and hydroxyethyl methyl cellulose with a mass ratio of 1:0.25;

[0067] S2: 0.08 parts of modified tannic acid, 0.32 parts of modified cellulose ether, and 0.002 parts of azobisisobutyronitrile are uniformly mixed in tetrahydrofuran, and irradiated under ultraviolet light with an emission wavelength of 365 nm and an intensity of 100 mW / cm2for 2 hours, and purified to obtain a cellulose ether derivative;

[0068] S3: 65 parts of cellulose ether derivative, 3.5 parts of EDTA, and 1.2 parts of film former are mixed to obtain the scale inhibitor.​

[0069] Detection Experiment 1: Static scale inhibition experiment: prepare CaCO3 solution, the concentration of Ca 2+ and HCO 3- in the system is 0.4 g / L and 0.8 g / L respectively; prepare CaSO4 solution, the concentration of Ca 2+ and SO 2- 4 in the system is 4.8 g / L and 5.1 g / L respectively;

[0070] According to the detection method of GB / T16632-2008 and GB / T22626-2008, under static condition, examples 1-3 and comparative examples 1-4 are respectively placed in calcium carbonate and calcium sulfate, and reacted at 50℃ for 6 hours, the scale inhibition performance of examples 1-3 and comparative examples 1-4 at the concentration of 20 mg / L is evaluated; as shown in Table 1.

[0071] Corrosion experiment: A3 carbon steel corrosion test piece is used as material; the corrosion test time is 72 hours, the temperature is 40℃, the corrosion inhibition of examples 1-3 and comparative examples 1-4 at the concentration of 20 mg / L is detected according to GB / T18175-2000; the annual corrosion rate (mm / a) is calculated according to the mass, area, density and corrosion time of A3 carbon steel corrosion test piece before and after the experiment; the corrosion inhibition of examples 1-3 and comparative examples 1-4 is evaluated according to the standard of GB50050-2007 “industrial circulating cooling water treatment design specification” that the annual corrosion rate reaches ≤0.075 mm / a; as shown in Table 1.

[0072] CaC03 rejection rate (%) CaSO4 rejection rate (%) Corrosion rate (mm / a) per year Example 1 98.2 99.4 0.0227 Example 2 98.4 99.7 0.0224 Example 3 97.9 99.2 0.0232 Comparative Example 1 82.7 83.2 0.0296 Comparative Example 2 90.5 91.1 0.0267 Comparative Example 3 87.4 89.2 0.0284 Comparative Example 4 84.6 85.3 0.0458

[0073] Table 1

[0074] Conclusion: Comparative example 1 is based on example 2, directly introducing cellulose ether, which reduces the scale inhibition rate of scale inhibitor for calcium carbonate and calcium sulfate, and enhances the corrosion inhibition performance, because the functional groups on 2,4-diamino-6-vinyl-S-triazine have the ability to form complexes with metal ions, 5-amino lysine improves the ability of cellulose ether to interact with water and corrosion inhibition, and improves its dispersibility and solubility in water, thereby benefiting the improvement of scale inhibition of scale inhibitor and the reduction of corrosion inhibition. Comparative example 2 is based on example 2, single introduction of high molecular cellulose ether in cellulose ether, thereby reducing the scale inhibition and corrosion inhibition of scale inhibitor, because the uniform mixing of high viscosity cellulose ether and low viscosity cellulose ether can combine the better thickening property of high viscosity cellulose ether and the better permeability of low viscosity cellulose ether, thereby preventing particle deposition and scale formation, and also better penetrating and dispersing existing dirt.

[0075] Comparative Example 3 is based on Example 2, and tannic acid is not introduced. The present application introduces tannic acid because the modification of cellulose ether will reduce the content of hydroxyl groups, thereby affecting the efficiency of scale inhibition. In order to improve the scale removal effect and corrosion inhibition of modified cellulose ether, carboxyl groups are introduced on tannic acid to increase the hydroxyl and carboxyl functional groups on cellulose derivatives, thereby enhancing the scale inhibition effect and corrosion inhibition of the scale inhibitor. Comparative Example 4 is based on Example 2, and polyaspartic acid / castor oil acid is not added, thereby causing the performance of the scale inhibitor to decline. Polyaspartic acid can form a complex or other bonding with calcium, magnesium and other ions in water, preventing the deposition of these ions on the surface of pipes and equipment, and also causing physical adsorption processes on the surface of carbon steel or inhibitor interface, thereby achieving corrosion inhibition. Castor oil acid has a certain surface activity, and can form a uniform lubricating film on the surface of pipes and equipment, reducing the adhesion of scale, thereby prolonging the service life of the equipment. Castor oil acid is covalently linked to polyaspartic acid, which can improve the compatibility of the two and reduce the deposition of metal ions on the surface of pipes and equipment, thereby reducing the corrosion rate of the metal surface and indirectly improving the corrosion inhibition.

[0076] Finally, it should be noted that the above only describes the preferred embodiments of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of changes or replacements within the technical scope disclosed in the present application, as long as they are within the spirit and principles of the present application. The embodiments and features in the embodiments can be combined with each other without conflict. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A process for the preparation of a cellulose ether based scale inhibitor characterized by: The method comprises the following steps: S1: grafting 5-amino lysine and 2,4-diamino-6-vinyl-S-triazine with cellulose ether to obtain modified cellulose ether; S2: compounding the modified tannic acid and the modified cellulose ether through click reaction to obtain cellulose ether derivative; S3: uniformly mixing the cellulose ether derivative, polyaspartic acid / castor oil acid, EDTA and film forming agent to obtain the scale inhibitor.

2. A process for the preparation of a cellulose ether based scale inhibitor according to claim 1, characterized in that: The raw materials of the scale inhibitor comprise the following components: 60-70 parts of cellulose derivative, 15-20 parts of polyaspartic acid / castor oil acid, 3-5 parts of EDTA and 1-1.5 parts of film forming agent by weight.

3. The method for preparing a scale inhibitor based on cellulose ether according to claim 1, characterized in that: The preparation method of the modified cellulose ether comprises the following steps: adding 5-amino lysine and 2,4-diamino-6-vinyl-S-triazine into deionized water and uniformly mixing to obtain a mixed solution A; adding cellulose ether and carbonyl diimidazole into tetrahydrofuran and uniformly mixing, adding the mixed solution A, and reacting at 30-40 DEG C for 12-16 hours, and then purifying to obtain the modified cellulose ether.

4. The method for preparing a scale inhibitor based on cellulose ether according to claim 3, characterized in that: The cellulose ether comprises 2-hydroxyethyl ether cellulose and hydroxyethyl methyl cellulose with a mass ratio of 1:(0.1-0.3). The raw materials of the modified cellulose ether comprise the following components: 9-13 parts of 5-amino lysine, 8-10 parts of 2,4-diamino-6-vinyl-S-triazine, 5-6 parts of carbonyl diimidazole, 20-30 parts of cellulose ether and 50-70 parts of tetrahydrofuran by weight.

5. The method for preparing a scale inhibitor based on cellulose ether according to claim 1, characterized in that: The preparation method of the modified tannic acid comprises the following steps: (1) adding tannic acid into pyridine and uniformly mixing at 35-45 DEG C, adding methyl tetrahydrophthalic anhydride, reacting for 1-2 hours, then increasing the temperature to 95-100 DEG C and continuously reacting for 12-20 hours, and then purifying to obtain carboxylated tannic acid; (2) adding the carboxylated tannic acid and cysteine into deionized water, reacting at 110-124 DEG C for 2-3 hours, and then adjusting the pH to 10 to obtain the modified tannic acid.

6. A process for the preparation of a cellulose ether based scale inhibitor according to claim 5, characterized in that: The raw materials of the carboxylated tannic acid comprise the following components: 4-6 parts of tannic acid, 10-20 parts of methyl tetrahydrophthalic anhydride and 45-55 parts of pyridine by weight; the mass ratio of cysteine to the carboxylated tannic acid is (0.008-0.012):

1.

7. The method for preparing a scale inhibitor based on cellulose ether according to claim 1, characterized in that: The preparation method of the cellulose ether derivative comprises the following steps: uniformly mixing the modified tannic acid, the modified cellulose ether and azobisisobutyronitrile in tetrahydrofuran, irradiating under ultraviolet light for 2-2.5 hours, and then purifying to obtain the cellulose ether derivative.

8. The method for preparing a scale inhibitor based on cellulose ether according to claim 7, characterized in that: The raw material of the cellulose ether derivative comprises the following components: 0.065-0.15 parts of modified tannin acid, 0.27-0.35 parts of cellulose ether derivative, 0.002-0.003 parts of AIBN, 18-25 parts of tetrahydrofuran by weight fraction; the process conditions of ultraviolet lamp irradiation are as follows: the emission wavelength is 365 nm, and the light intensity is 80-110 mW / cm 2 .

9. The method for preparing a scale inhibitor based on cellulose ether according to claim 1, characterized in that: The preparation method of the polyaspartic acid / castor oil acid is as follows: uniformly mixing castor oil acid, thioglycerol and 2-hydroxy-2-methyl-1-phenyl-1-propanone, irradiating under ultraviolet light with light intensity of 50-60 mW / cm 2 for 1.5-2 hours to obtain modified castor oil acid; adding polyaspartic acid into ethanol, adding the modified castor oil acid, and reacting at 75-85°C for 4-5 hours, and continuously reacting for 8-10 hours after the temperature is reduced to room temperature to obtain polyaspartic acid / castor oil acid.

10. The method for preparing a scale inhibitor based on cellulose ether according to claim 9, characterized in that: The raw materials of the modified castor oil acid comprise the following components: 1-1.2 parts of castor oil acid, 2-2.5 parts of thio glycerol and 0.015-0.02 parts of 2-hydroxy-2-methyl-1-phenyl-1-propanone by weight; the mass ratio of polyaspartic acid to the modified castor oil acid is (0.4-0.6):1.