Preparation method and application of multifunctional composite scale and corrosion inhibitor

Abstract

The invention relates to a preparation method and application of a multifunctional composite scale and corrosion inhibitor, and belongs to the technical field of industrial water treatment.The multifunctional composite scale and corrosion inhibitor is prepared from, by weight, 30-55 parts of carboxylic acid monomers, 5-20 parts of sulfonate monomers, 15-35 parts of natural polysaccharides, 5-15 parts of organophosphorus compounds, 1-10 parts of redox agents and 1-5 parts of azole derivatives. 5-20 parts of a polycarboxylic acid copolymer, 1-10 parts of a chain transfer agent and 40-80 parts of deionized water. According to the preparation method and application of the multifunctional composite scale and corrosion inhibitor, the composite scale and corrosion inhibitor prepared by adopting the preparation method has the calcium carbonate scale inhibition rate of 92-98%, the calcium phosphate scale inhibition rate of 90-99%, the dispersion rate of 40-70% and the corrosion inhibition rate of 97-99%, is obviously superior to that of a traditional medicament, and is good in high temperature resistance, efficient, green, environment-friendly and good in biodegradability; and the influence on the environment is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of industrial water treatment, in particular to a preparation method and application of a multifunctional composite scale and corrosion inhibitor. BACKGROUND

[0002] With the increasing scarcity of water resources, industrial circulating cooling water systems generally use chemical agents for treatment to improve the efficiency of water recycling. However, with the increase in concentration ratio, the concentration of salt, hardness ions and microorganisms in circulating water continues to accumulate, leading to problems such as internal scaling, equipment corrosion and microbial growth in the system, which seriously affects the heat exchange efficiency and shortens the service life of the equipment. Traditional scale and corrosion inhibitors mostly use a scheme of polymeric carboxylic acid (such as polyacrylic acid PAA, sulfonate copolymer AA-AMPS) and organic phosphate (such as HEDP, ATMP) complex, but this system has obvious defects, i.e. organic phosphate easily leads to eutrophication of water bodies, and sulfonate copolymer has insufficient inhibition of calcium carbonate scale, although it has dispersibility and high temperature resistance; at the same time, natural high molecular materials can chelate calcium and magnesium ions due to the enrichment of carboxyl groups, but have poor stability.

[0003] Prior art such as patent publication CN105621639B discloses a scale and corrosion inhibitor composition and scale and corrosion inhibitor and its application. The scale and corrosion inhibitor composition contains 1-[N,N'-di(2-hydroxyethyl)aminomethyl]benzotriazole or its derivative, carboxylic acid group-containing homopolymer, sulfonic acid group-containing copolymer and water-soluble zinc salt, and the weight ratio of each component is 1:0.5-10:0.5-10:0.3-7.5, preferably 1:2-5:2-5:0.5-3.5. The scale and corrosion inhibitor of the invention avoids the use of phosphorus-containing compounds and non-renewable molybdate or tungstate, etc., has the characteristics of no phosphorus and no nitrogen; and has high tolerance to calcium and alkali, resistance to corrosion of high concentration of chloride ions and sulfate ions, and wide range of water quality adaptation, providing technology for the operation of circulating water at high concentration ratio and the reduction of wastewater discharge.

[0004] Prior art such as patent publication CN103771600B discloses a composite scale and corrosion inhibitor and its application as well as a circulating water treatment method. The composite scale and corrosion inhibitor contains a dispersant, an organic phosphonic acid scale and corrosion inhibitor and a manganese salt, and the weight ratio of the dispersant, the organic phosphonic acid scale and corrosion inhibitor and the manganese salt is 1:0.1-2:0.025-0.5, wherein the weight of the manganese salt is calculated based on manganese ions. The composite scale and corrosion inhibitor of the invention has a good synergistic effect with non-oxidizing bactericides, especially isothiazolinone, can significantly improve the bactericidal effect of isothiazolinone, and shows fast bactericidal effect and long drug effect time.

[0005] The above patent introduces sulfonic acid groups on the basis of carboxylic acid polymers, which can effectively improve the ability to inhibit calcium phosphate, but the calcium carbonate blocking performance is generally low. Sodium alginate can capture metal ions due to its rich surface functional groups (such as carboxyl and hydroxyl groups), but it has poor thermal stability and is difficult to be used alone.

[0006] The present application provides a preparation method of a multifunctional composite scale and corrosion inhibitor to solve the problem of poor thermal stability of natural polysaccharides by free radical graft copolymerization of natural macromolecular materials and AA / AMPS, and to enhance dispersibility by using the biodegradable skeleton. The compounded system realizes broad-spectrum scale inhibition through the triple action of "ion exchange-lattice distortion-space shielding", especially suitable for harsh water quality with high chlorine and high hardness. SUMMARY

[0007] To overcome the shortcomings of the prior art, the present application provides a preparation method and application of a multifunctional composite scale and corrosion inhibitor, which has the advantages of high scale inhibition rate, high corrosion inhibition rate, good high temperature resistance and good environmental protection effect, and solves the problems in the above background art.

[0008] To achieve the above-mentioned purpose, the present application provides the following technical scheme:

[0009] A preparation method of a multifunctional composite scale and corrosion inhibitor, comprising the following raw materials in parts by weight:

[0010] Carboxylic acid monomer 30-55 parts, sulfonate monomer 5-20 parts, natural polysaccharide 15-35 parts, organic phosphorus compound 5-15 parts, redox agent 1-10 parts, azole derivative 1-5 parts, polycarboxylic acid copolymer 5-20 parts, chain transfer agent 1-10 parts, deionized water 40-80 parts;

[0011] Further comprising the following preparation steps:

[0012] S1, deionized water is added to the reactor, and natural polysaccharide, carboxylic acid monomer, reducing agent and chain transfer agent are added in sequence, and the temperature is raised to 60℃, and nitrogen is blown to remove oxygen;

[0013] S2, after dissolving, continue to heat to 80℃;

[0014] S3, under constant temperature conditions, first add the oxidizing agent aqueous solution through a constant pressure dropping funnel for 5 minutes, then add the sulfonate monomer and the oxidizing agent aqueous solution at the same time, and control the dropping speed to be completed in 3 hours;

[0015] S4, after the addition is completed, continue to react for 1 hour, and when the temperature drops to 40℃, add the polycarboxylic acid copolymer and the azole derivative in sequence and stir uniformly for 20-40 minutes to obtain the multifunctional composite scale and corrosion inhibitor.

[0016] Furthermore, the carboxylic acid polymer is one or more of acrylic acid (AA), maleic acid (MA), and itaconic acid (IA).

[0017] Furthermore, the sulfonate monomer is one or more of sodium allyl sulfonate (SAS), 2-acrylamido-2-methylpropanesulfonic acid (AMPS), and sodium methyl allyl sulfonate (SMAS).

[0018] Furthermore, the natural polysaccharides are cellulose and its derivatives, chitin, alginic acid, and starch.

[0019] Furthermore, the redox agent includes an oxidant and a reducing agent, wherein the oxidant is one or more of sodium persulfate, ammonium persulfate, potassium persulfate, and hydrogen peroxide.

[0020] Furthermore, the reducing agent is one or more of sodium bisulfite, sodium metabisulfite, and anhydrous sodium sulfite.

[0021] Furthermore, the azole derivative is one or more of methylbenzotriazole (TTA), benzotriazole (BTA), and mercaptobenzothiazole (MBT).

[0022] Furthermore, the polycarboxylic acid copolymer is one or more of hydrolyzed polymaleic anhydride (HPMA) and maleic anhydride / acetic acid copolymer (MA / AA).

[0023] Furthermore, the chain transfer agent is one or more of sodium hypophosphite, isopropanol, dodecyl mercaptan, and mercaptoethanol.

[0024] This invention also provides an application of a multifunctional composite scale and corrosion inhibitor for scale inhibition, corrosion inhibition, and dispersion treatment of water with high chlorine and high hardness.

[0025] Compared with the prior art, the present invention provides a method for preparing a multifunctional composite scale and corrosion inhibitor and its application, which has the following beneficial effects:

[0026] 1. Preparation method and application of the multifunctional composite scale and corrosion inhibitor: The composite scale and corrosion inhibitor prepared by the above preparation method has a scale inhibition rate of 92-98% for calcium carbonate scale, a scale inhibition rate of 90-99% for calcium phosphate scale, a dispersion rate of 40%-70%, and a corrosion inhibition rate of 97-99%, which is significantly better than traditional agents.

[0027] 2. Preparation method and application of the multifunctional composite scale and corrosion inhibitor: The composite scale and corrosion inhibitor prepared by the above preparation method has good high temperature resistance, high efficiency, green and environmentally friendly properties, good biodegradability, and reduces the impact on the environment.

[0028] 3. The preparation method and application of the multifunctional composite scale and corrosion inhibitor. The composite scale and corrosion inhibitor prepared by the preparation method can be used in high-chlorine and high-hardness circulating cooling water systems and is suitable for the treatment of circulating cooling water under harsh conditions in chemical industry, smelting and light industry and the like. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0030] Embodiment 1

[0031] The multifunctional composite scale and corrosion inhibitor in the embodiment has the following raw material components by weight fraction:

[0032] Maleic acid (MA) 30 parts, 2-acrylamido-2-methylpropane sulfonic acid (AMPS) 15 parts, sodium alginate 15 parts, ammonium persulfate 5 parts, sodium bisulfite 5 parts, BTA 2 parts, MA / AA copolymer 10 parts, isopropyl alcohol 5 parts and pure water 50 parts.

[0033] The preparation method of the multifunctional composite scale and corrosion inhibitor in the embodiment is as follows:

[0034] S1: The carboxylic acid monomer, natural polysaccharide, reducing agent, chain transfer agent and deionized water are sequentially added to a reaction device according to the above weight fractions, and the temperature is raised to 60°C, and nitrogen is passed;

[0035] S2: After dissolution, the temperature is continuously raised to 80°C, and the temperature is kept constant;

[0036] S3: The sulfonate monomer and oxidizing agent are added to a dropping funnel according to the above weight fractions, the oxidizing agent is first added for 5 min, and then added at the same time, the adding speed is controlled to be dropped for 3 h, and the stirring reaction is continuously carried out for 1 h;

[0037] S4: After the temperature is lowered to 40°C, the polycarboxylic acid copolymer and azole derivative are sequentially added and uniformly stirred for 30 min to obtain the multifunctional composite scale and corrosion inhibitor.

[0038] Embodiment 2

[0039] The multifunctional composite scale and corrosion inhibitor in the embodiment has the following raw material components by weight fraction:

[0040] Acrylic acid (AA) 30 parts, 2-acrylamido-2-methylpropane sulfonic acid (AMPS) 15 parts, sodium alginate 15 parts, ammonium persulfate 5 parts, sodium bisulfite 5 parts, BTA 2 parts, hydrolyzed polymaleic anhydride 10 parts, isopropyl alcohol 5 parts, pure water 50 parts.

[0041] The preparation method of the multifunctional composite scale and corrosion inhibitor in this embodiment is as follows:

[0042] S1: The carboxylic acid monomer, natural polysaccharide, reducing agent, chain transfer agent, and deionized water are sequentially added to the reaction device according to the above weight fractions, and the temperature is raised to 60°C with nitrogen gas;

[0043] S2: After dissolving, continue to heat to 80°C and keep constant temperature;

[0044] S3: The sulfonate monomer and oxidizing agent are added to the dropping funnel according to the above weight fractions, first drop the oxidizing agent for 5 minutes, then drop them at the same time, control the adding speed to drop in 3 hours, continue to stir for 1 hour;

[0045] S4: When the temperature drops to 40°C, the polycarboxylic acid copolymer and azole derivative are sequentially added and uniformly stirred for 30 minutes to obtain the multifunctional composite scale and corrosion inhibitor.

[0046] Example 3:

[0047] The raw material component weight fractions of the multifunctional composite scale and corrosion inhibitor in this embodiment are as follows:

[0048] Maleic acid (MA) 30 parts, 2-acrylamido-2-methylpropane sulfonic acid (AMPS) 15 parts, starch 15 parts, ammonium persulfate 5 parts, sodium bisulfite 5 parts, BTA 2 parts, AA / HPA copolymer 10 parts, isopropyl alcohol 5 parts, pure water 50 parts.

[0049] The preparation method of the multifunctional composite scale and corrosion inhibitor in this embodiment is as follows:

[0050] S1: The carboxylic acid monomer, natural polysaccharide, reducing agent, chain transfer agent, and deionized water are sequentially added to the reaction device according to the above weight fractions, and the temperature is raised to 60°C with nitrogen gas;

[0051] S2: After dissolving, continue to heat to 80°C and keep constant temperature;

[0052] S3: The sulfonate monomer and oxidizing agent are added to the dropping funnel according to the above weight fractions, first drop the oxidizing agent for 5 minutes, then drop them at the same time, control the adding speed to drop in 3 hours, continue to stir for 1 hour;

[0053] S4: When the temperature drops to 40°C, the polycarboxylic acid copolymer and azole derivative are sequentially added and uniformly stirred for 30 minutes to obtain the multifunctional composite scale and corrosion inhibitor.

[0054] Example 4:

[0055] The raw material components of the multifunctional composite scale and corrosion inhibitor in this example are as follows: maleic acid (MA) 30 parts, 2-acrylamido-2-methylpropane sulfonic acid (AMPS) 15 parts, starch 15 parts, ammonium persulfate 5 parts, sodium bisulfite 5 parts, BTA 2 parts, AA / HPA copolymer 10 parts, sodium hypophosphite 5 parts, and pure water 60 parts.

[0056] The preparation method of the multifunctional composite scale and corrosion inhibitor in this example is as follows:

[0057] S1: The carboxylic acid monomer, natural polysaccharide, reducing agent, chain transfer agent, and deionized water are sequentially added to the reaction device in the above weight proportions, and the temperature is raised to 60°C with nitrogen gas;

[0058] S2: After dissolution, the temperature is continuously raised to 80°C and kept constant;

[0059] S3: The sulfonate monomer and oxidizing agent are added to the dropping funnel in the above weight proportions. First, the oxidizing agent is added dropwise for 5 minutes, and then both are added simultaneously. The addition speed is controlled to be completed in 3 hours, and the stirring reaction is continued for 1 hour;

[0060] S4: When the temperature drops to 40°C, the polycarboxylic acid copolymer and azole derivative are sequentially added and uniformly stirred for 30 minutes to obtain the multifunctional composite scale and corrosion inhibitor.

[0061] Example 5:

[0062] The raw material components of the multifunctional composite scale and corrosion inhibitor in this example are as follows:

[0063] Itaconic acid (IA) 30 parts, 2-acrylamido-2-methylpropane sulfonic acid (AMPS) 15 parts, sodium alginate 25 parts, hydrogen peroxide 5 parts, sodium bisulfite 5 parts, TTA 2 parts, MA / AA copolymer 10 parts, sodium hypophosphite 5 parts, and pure water 60 parts.

[0064] The preparation method of the multifunctional composite scale and corrosion inhibitor in this example is as follows:

[0065] S1: The carboxylic acid monomer, natural polysaccharide, reducing agent, chain transfer agent, and deionized water are sequentially added to the reaction device in the above weight proportions, and the temperature is raised to 60°C with nitrogen gas;

[0066] S2: After dissolution, the temperature is continuously raised to 80°C and kept constant;

[0067] S3: The sulfonate monomer and oxidizing agent are added to the dropping funnel in the above weight proportions. First, the oxidizing agent is added dropwise for 5 minutes, and then both are added simultaneously. The addition speed is controlled to be completed in 3 hours, and the stirring reaction is continued for 1 hour;

[0068] S4: When the temperature drops to 40℃, add the polycarboxylic acid copolymer and azole derivative in sequence and uniformly stir for 30 min to obtain the multifunctional composite scale and corrosion inhibitor.

[0069] Comparative Example 1:

[0070] The raw material components of the multifunctional composite scale and corrosion inhibitor in this example are as follows:

[0071] Acrylic acid (AA) 30 parts, 2-acrylamido-2-methylpropane sulfonic acid (AMPS) 15 parts, ammonium persulfate 5 parts, sodium bisulfite 5 parts, BTA 2 parts, hydrolyzed polymaleic anhydride 10 parts, isopropyl alcohol 5 parts, and pure water 50 parts.

[0072] The preparation method of the multifunctional composite scale and corrosion inhibitor in this example is as follows:

[0073] S1: Add the carboxylic acid monomer, reducing agent, chain transfer agent, and deionized water in sequence into the reaction device according to the above weight fractions, and raise the temperature to 60℃ and pass nitrogen gas;

[0074] S2: After dissolving, continue to raise the temperature to 80℃ and maintain the temperature;

[0075] S3: Add the sulfonate monomer and oxidizing agent into the dropping funnel according to the above weight fractions, first add the oxidizing agent for 5 min, then add them at the same time, control the adding speed to be completed in 3 h, and continue to stir for 1 h;

[0076] S4: When the temperature drops to 40℃, add the polycarboxylic acid copolymer and azole derivative in sequence and uniformly stir for 30 min to obtain the multifunctional composite scale and corrosion inhibitor.

[0077] Comparative Example 2:

[0078] The raw material components of the multifunctional composite scale and corrosion inhibitor in this example are as follows:

[0079] Acrylic acid (AA) 30 parts, 2-acrylamido-2-methylpropane sulfonic acid (AMPS) 15 parts, sodium alginate 15 parts, ammonium persulfate 5 parts, sodium bisulfite 5 parts, BTA 2 parts, isopropyl alcohol 5 parts, and pure water 50 parts.

[0080] The preparation method of the multifunctional composite scale and corrosion inhibitor in this example is as follows:

[0081] S1: Add the carboxylic acid monomer, natural polysaccharide, reducing agent, chain transfer agent, and deionized water in sequence into the reaction device according to the above weight fractions, and raise the temperature to 60℃ and pass nitrogen gas;

[0082] S2: After dissolving, continue to raise the temperature to 80℃ and maintain the temperature;

[0083] S3: The sulfonate monomer and oxidant are added into the dropping funnel according to the above weight proportions, the oxidant is first added for 5 min, then added simultaneously, the adding speed is controlled to be completed in 3 h, and the stirring reaction is continued for 1 h;

[0084] S4: After the temperature drops to 40 DEG C, the azole derivative is added and uniformly stirred for 30 min to obtain the multifunctional composite scale and corrosion inhibitor.

[0085] Comparative Example 3:

[0086] The raw material components of the multifunctional composite scale and corrosion inhibitor in the embodiment are as follows:

[0087] Itaconic acid (IA) 30 parts, 2-acrylamido-2-methylpropane sulfonic acid (AMPS) 15 parts, sodium alginate 25 parts, hydrogen peroxide 5 parts, sodium bisulfite 5 parts, MA / AA copolymer 10 parts, sodium hypophosphite 5 parts, and pure water 60 parts.

[0088] The preparation method of the multifunctional composite scale and corrosion inhibitor in the embodiment is as follows:

[0089] S1: The carboxylic acid monomer, natural polysaccharide, reducing agent, chain transfer agent, and deionized water are sequentially added into a reaction device according to the above weight proportions, and the temperature is raised to 60 DEG C, and nitrogen is passed;

[0090] S2: After dissolution, the temperature is continuously raised to 80 DEG C, and the temperature is kept constant;

[0091] S3: The sulfonate monomer and oxidant are added into the dropping funnel according to the above weight proportions, the oxidant is first added for 5 min, then added simultaneously, the adding speed is controlled to be completed in 3 h, and the stirring reaction is continued for 1 h;

[0092] S4: After the temperature drops to 40 DEG C, the azole derivative is added and uniformly stirred for 30 min to obtain the multifunctional composite scale and corrosion inhibitor.

[0093] In order to better illustrate the properties of the composite scale and corrosion inhibitor provided in the embodiments of the application, the composite scale and corrosion inhibitors prepared in Examples 1-5 and Comparative Examples 1-3 are subjected to performance detection.

[0094] The composite scale and corrosion inhibitors prepared in Examples 1-5 and Comparative Examples 1-3 are subjected to calcium carbonate scale inhibition test, calcium phosphate scale inhibition experiment, and rotating coupon corrosion test according to “Determination of Scale Inhibition Performance of Water Treatment Agent - Calcium Carbonate Deposition Method” (GB-T16632-2008), “Determination of Scale Inhibition Performance of Water Treatment Agent - Calcium Phosphate Deposition Method” (GB / T 22626-2008), and “Determination of Corrosion Inhibition Performance of Water Treatment Agent - Rotating Coupon Method” (GBT-18175-2014).

[0095] Dispersing performance test: the hydrolysis product of ferrous sulfate heptahydrate at high pH value is used as the suspension medium of iron oxide, heated and stirred, and the supernatant is taken after standing, and the transmittance is measured by 722 spectrophotometer (420 nm, 3 cm cuvette). The smaller the transmittance, the better the dispersing effect.

[0096] Test conditions: the concentration of calcium ions is 150 mg / L, the concentration of ferrous ions is 10 mg / L (prepared by ferrous sulfate heptahydrate), the pH is 8.7 (adjusted by 0.5 mg / L of sodium tetraborate), and the transmittance of the supernatant is measured in a water bath at 50°C.

[0097] The composite scale and corrosion inhibitors prepared in Examples 1-5 and Comparative Examples 1-3 are tested for performance according to the relevant methods, and the dosage is 20 ppm. The scale inhibition rate test results are shown in Table 1, the corrosion rate results are shown in Table 2, and the dispersing performance results are shown in Table 3.

[0098] Table 1: Scale inhibition rate test results

[0099] Experimental Group Scale Inhibition Rate (Calcium Carbonate) Scale Inhibition Rate (Calcium Phosphate) Example 1 93.18% 93.23% Example 2 95.24% 98.67% Example 3 94.47% 96.86% Example 4 95.96% 99.54% Example 5 97.18% 97.35% Comparative Example 1 51.06% 54.06% Comparative Example 2 54.13% 50.24% Comparative Example 3 95.21% 92.82%

[0100] Table 2: Corrosion rate test results

[0101] Experimental Group Carbon Steel Corrosion Rate Brass Corrosion Rate Stainless Steel Corrosion Rate Example 1 0.042 mm / a 0.0034 mm / a 0.0030 mm / a Example 2 0.037 mm / a 0.0029 mm / a 0.0028 mm / a Example 3 0.045 mm / a 0.0036 mm / a 0.0030 mm / a Example 4 0.041 mm / a 0.0032 mm / a 0.0029 mm / a Example 5 0.032 mm / a 0.0027 mm / a 0.0026 mm / a Comparative Example 1 0.105 mm / a 0.0093 mm / a 0.0105 mm / a Comparative Example 2 0.113 mm / a 0.0101 mm / a 0.0113 mm / a Comparative Example 3 0.169 mm / a 0.0423 mm / a 0.0405 mm / a Blank 0.866 mm / a 0.0698 mm / a 0.0781 mm / a

[0102] Table 3: Dispersing performance test results

[0103] Experimental Group Transmittance Example 1 63.59% Example 2 58.63% Example 3 60.74% Example 4 50.87% Example 5 42.36% Comparative Example 1 90.45% Comparative Example 2 88.69% Comparative Example 3 45.23%

[0104] The results of Table 1, Table 2 and Table 3 show that the products of Examples 1-5 have great advantages in calcium carbonate scale inhibition, calcium phosphate scale inhibition, corrosion inhibition and dispersing performance. Under the same water quality conditions, the comparative examples 1-3 prepared by the composite scale and corrosion inhibitor are compared with the effects of Examples 1-5. The absence of natural polysaccharide or polycarboxylic acid copolymer will seriously affect the calcium carbonate scale inhibition, calcium phosphate scale inhibition and dispersing performance of the product, and the azole derivative will greatly affect the corrosion inhibition performance of the product, which shows a synergistic effect.

[0105] It should be noted that in this document, the terms "include", "contain" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device. Without more limitations, the element defined by the statement "including a" does not exclude the presence of another identical element in the process, method, article or device including the element.

[0106] While embodiments of the application have been shown and described, it is to be understood that the embodiments described are merely exemplary of the principles and application of the present application. Numerous modifications and adaptions can be effected without departing from the spirit and scope of the present application, which is not limited to the exact construction and arrangement described. It is intended, therefore, to cover all modifications and adaptions that fall within the scope of the claims and their equivalents.

Claims

1. A method for preparing a multifunctional composite scale and corrosion inhibitor, characterized in that, The raw materials include the following components in parts by weight: carboxylic acid monomer 30-55 parts, sulfonate monomer 5-20 parts, natural polysaccharide 15-35 parts, organic phosphorus compound 5-15 parts, oxidation-reduction agent 1-10 parts, azole derivative 1-5 parts, polycarboxylic acid copolymer 5-20 parts, chain transfer agent 1-10 parts, and deionized water 40-80 parts; It also includes the following preparation steps: S1, adding deionized water in a reactor, and sequentially adding natural polysaccharide, carboxylic acid monomer, reducing agent and chain transfer agent, heating to 60℃, and removing oxygen by nitrogen; S2, after dissolving, continue to heat to 80℃; S3, under constant temperature conditions, first add the aqueous solution of oxidizing agent through a constant pressure dropping funnel for 5 minutes, then simultaneously add the sulfonate monomer and the aqueous solution of oxidizing agent, and control the dropping speed to be completed in 3 hours; S4, after the dropping is completed, continue to react for 1 hour, and when the temperature drops to 40℃, sequentially add the polycarboxylic acid copolymer and the azole derivative, and uniformly stir for 20-40 minutes to obtain the multifunctional composite scale and corrosion inhibitor.

2. The preparation method of the multifunctional composite scale and corrosion inhibitor according to claim 1, characterized in that: the carboxylic acid polymer is one or more of acrylic acid (AA), maleic acid (MA) and itaconic acid (IA).

3. The preparation method of the multifunctional composite scale and corrosion inhibitor according to claim 1, characterized in that: the sulfonate monomer is one or more of allyl sodium sulfonate (SAS), 2-acrylamido-2-methylpropane sulfonic acid (AMPS) and sodium methyl allyl sulfonate (SMAS).

4. The preparation method of the multifunctional composite scale and corrosion inhibitor according to claim 1, characterized in that: the natural polysaccharide is cellulose and its derivatives, chitin and alginic acid, and starch.

5. The preparation method of the multifunctional composite scale and corrosion inhibitor according to claim 1, characterized in that: the oxidation-reduction agent includes an oxidizing agent and a reducing agent, and the oxidizing agent is one or more of sodium persulfate, ammonium persulfate, potassium persulfate and hydrogen peroxide.

6. The preparation method of the multifunctional composite scale and corrosion inhibitor according to claim 1, characterized in that: the reducing agent is one or more of sodium bisulfite, sodium pyrosulfite and anhydrous sodium sulfite.

7. The preparation method of the multifunctional composite scale and corrosion inhibitor according to claim 1, characterized in that: the azole derivative is one or more of methyl benzotriazole (TTA), benzotriazole (BTA) and mercaptobenzothiazole (MBT).

8. The preparation method of the multifunctional composite scale and corrosion inhibitor according to claim 7, characterized in that: the polycarboxylic acid copolymer is one or more of hydrolyzed polymaleic anhydride (HPMA) and maleic acid-acrylic acid copolymer (MA / AA).

9. The preparation method of the multifunctional composite scale and corrosion inhibitor according to claim 1, characterized in that: the chain transfer agent is one or more of sodium hypophosphite, isopropyl alcohol, dodecyl mercaptan and mercaptoethanol.

10. The use of the multifunctional composite scale and corrosion inhibitor, prepared by the method of any one of claims 1-9, characterized in that: It is used for scale inhibition, corrosion inhibition and dispersion treatment of high-chlorine and high-hardness water.