Corrosion and scale inhibitor for sewage recycling system

Abstract

The invention belongs to the field of oil refining and chemical engineering, and discloses a corrosion and scale inhibitor for a sewage recycling system, which is prepared by taking water as a solvent and polycis-butadiene acid, 2-phosphate-1, 2, 4-tricarboxylic acid butane, benzotriazole, epoxy maleic acid-allyl ester-acrylamide-sulfonate multipolymer, ethylene diamine tetraacetic acid disodium salt and zinc sulfate monohydrate as solutes through stirring. The corrosion and scale inhibitor is prepared by mixing the raw materials according to a certain proportion, belongs to a low-phosphorus formula, and can achieve good corrosion and scale inhibition effects on a circulating water system taking recycled sewage as make-up water, prolong the service life of water cooling equipment and guarantee long-period stable operation of the system; the corrosion and scale inhibition raw materials are conventional and low in price; due to the national call of energy conservation and emission reduction, the make-up water of the circulating water system is diversified in type, and the circulating water system is suitable for circulating water treatment with Yangtze River water as make-up water and is also suitable for circulating water treatment with recycled sewage as make-up water.

Description

Technical Field

[0001] The invention relates to the technical field of oil refining and chemical engineering, and in particular to a corrosion and scale inhibitor for a wastewater recycling system. Background Art

[0002] my country is short of water resources, and the per capita water demand is only one-fourth of the world average. Economists predict that by 2030, China's industrial water use will increase from 52 billion m3 per year to 3 Increased to 269 billion m 3 Water not only affects the development of industry, but is also a major factor restricting economic development. Refining and chemical companies in most regions face different water pressures. The implementation of national water resource quota use and total pollutant emission control management systems requires refining and chemical companies to attach great importance to the resource utilization of sewage. Water conservation and emission reduction are even more important issues that must be resolved for companies to achieve sustainable development.

[0003] The water consumption and wastewater discharge per ton of oil in oil refining enterprises are both high. Implementing wastewater reuse is an effective way to reduce fresh water consumption and wastewater discharge. The circulating water system is a large industrial water user. After wastewater reuse is realized, the wastewater can be solved, and the fresh water consumption and wastewater discharge of enterprises can be reduced accordingly. The water consumption and wastewater discharge per ton of oil are gradually reduced, which has good economic and environmental benefits.

[0004] The salt content in the recycled wastewater is high, and the water quality fluctuates greatly. The corrosive ions (chloride ions, sulfate ions, conductivity, alkalinity (low), etc.) and scaling ions (calcium ions, magnesium ions, etc.) in the water body are higher than those in fresh water. Reusing such water quality in the circulating water system is not conducive to the stability of daily water quality, and has a great impact on the corrosion and scaling of equipment and pipelines. In serious cases, it will cause problems such as pipeline perforation and water cooling equipment leakage. Summary of the invention

[0005] The purpose of the present invention is to provide a corrosion inhibitor and scale inhibitor for a reuse sewage system. The provided corrosion inhibitor and scale inhibitor is suitable for circulating water treatment using Yangtze River water as supplementary water, and is also suitable for circulating water treatment using reuse sewage as supplementary water.

[0006] The present invention is achieved through the following technical scheme: a corrosion inhibitor and scale inhibitor for a reuse sewage system, which uses water as a solvent and polysuccinic acid, 2-phospho-1,2,4-tricarboxylic acid butane, benzotriazole, epoxy maleic acid-propylene ester-acrylamide-sulfonate multipolymer, disodium ethylenediaminetetraacetic acid, and zinc sulfate monohydrate as solutes, which are mixed in a certain proportion.

[0007] In order to further better realize the corrosion and scale inhibitor for reuse sewage system described in the present invention, the following configuration is particularly adopted: its raw material components include the following mass percentages: the solute and solvent of the corrosion and scale inhibitor are composed of the following components by mass percentage:

[0008]

[0009] In order to better realize the corrosion and scale inhibitor for reuse sewage system described in the present invention, the following configuration is particularly adopted: the solute and solvent of the corrosion and scale inhibitor are composed of the following components by mass percentage:

[0010]

[0011]

[0012] In order to better realize the corrosion and scale inhibitor for reuse sewage system described in the present invention, the following configuration is particularly adopted: the molecular formula of the epoxy maleic acid-propylene ester-acrylamide-sulfonate multi-polymer is: ((C3H3O2R)x-(C4H2O5)y-(C7H 13 O4NS)z), the relative molecular weight is between 8000-12000; epoxy maleic acid-propylene ester-acrylamide-sulfonate multipolymer is a multipolymer containing carboxyl, carbonyl, amide and sulfonic acid groups, with high dispersibility and scale inhibition performance. Compared with conventional acrylic acid-sulfonate co-dipolymer and maleic acid-acrylic acid dipolymer, it has more functional groups, is not monodisperse, has superior scale inhibition performance, and has good zinc stabilization and iron resistance.

[0013] In order to better realize the corrosion and scale inhibitor for a reuse sewage system described in the present invention, the following configuration is particularly adopted: the water is pure water.

[0014] In order to better realize the corrosion inhibitor and scale inhibitor for reused sewage system described in the present invention, the following setting method is particularly adopted: the corrosion inhibitor and scale inhibitor is added at a concentration of 50-100 mg / L when used as a corrosion inhibitor and scale inhibitor; the corrosion inhibitor and scale inhibitor is suitable for circulating water systems using Yangtze River water as supplementary water, and is also suitable for circulating water systems using reused sewage as supplementary water; it is suitable for circulating water treatment with conductivity <5000us / cm and alkalinity + calcium hardness <1100mg / L, and at the same time, the corrosion and scaling of carbon steel, stainless steel and copper equipment in the system are controlled.

[0015] Since the recycled sewage has not been deeply treated, there are cases where the conductivity, sulfate, chloride ion, total iron and other corrosive ions do not meet the water quality requirements of the circulating water system supplementary water in some periods of time. The water quality is harsh, so the corrosion performance requirements of the corrosion inhibitor are more stringent. In order to better realize the corrosion inhibitor for the recycled sewage system described in the present invention, the following setting method is particularly adopted: the corrosion inhibitor is added to the circulating water body at a certain concentration (such as a concentration of 50 to 100 mg / L), which can combine with the ions in the water body to form a protective film on the surface of the equipment, effectively ensuring the stability of the equipment surface, and can alleviate the corrosion and scaling of the equipment.

[0016] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0017] The invention has a wide application range: it is applicable to the circulating water treatment using the Yangtze River water as the supplementary water, and is also applicable to the circulating water treatment using the recycled sewage as the supplementary water.

[0018] The present invention can effectively solve the corrosion and scaling problems caused by the fluctuation of recycled sewage water quality and the high content of corrosive ions and scaling ions, and ensure the long-term stable operation of the device.

[0019] The present invention has good environmental protection and economic benefits. Because of its superior corrosion and scale inhibition performance, it effectively ensures the reuse of recycled sewage in the device. At the same time, it reduces the amount of sewage discharged, the amount of COD discharged, and the consumption of fresh water, ensuring the green development of enterprises and society.

[0020] The corrosion and scale inhibitor provided by the present invention is a low-phosphorus formula, which can play a good corrosion and scale inhibition effect on the circulating water system using recycled sewage as supplementary water, delay the service life of water cooling equipment, and ensure the long-term stable operation of the system; the corrosion and scale inhibition raw materials are conventional and low-priced; due to the national call for energy conservation and emission reduction, the types of supplementary water in the circulating water system are diversified, and the present invention is suitable for circulating water treatment using Yangtze River water as supplementary water, and is also suitable for circulating water treatment using recycled sewage as supplementary water; the present invention has good environmental protection and social benefits, and can reduce the amount of sewage discharged, fresh water consumption, and COD discharged by enterprises. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a test diagram of a corrosion inhibition test conducted in a laboratory using the corrosion and scale inhibitor of the present invention.

[0022] Figure 2 This is a test diagram of a scale inhibition test conducted in a laboratory using the corrosion and scale inhibitor of the present invention.

[0023] Figure 3 The on-site operation diagram of the heat exchanger is monitored after the corrosion and scale inhibitor of the present invention is applied.

[0024] Figure 4 This is a morphology diagram of the on-site hanging plate after the corrosion and scale inhibitor of the present invention is applied.

[0025] Figure 5 This is a diagram showing the operating effect of an on-site water cooler after applying the corrosion and scale inhibitor of the present invention.

[0026] Figure 6 This is a statistical diagram of the scaling of the water cooler on site after the corrosion and scale inhibitor of the present invention is applied. DETAILED DESCRIPTION

[0027] The present invention is further described in detail below in conjunction with examples, but the embodiments of the present invention are not limited thereto.

[0028] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the invention claimed for protection, but merely represents the selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0029] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0030] Example 1

[0031] A corrosion and scale inhibitor for a reuse sewage system, which is suitable for circulating water treatment using Yangtze River water as supplementary water and also suitable for circulating water treatment using reuse sewage as supplementary water. The corrosion and scale inhibitor is prepared by mixing water as solvent, polysuccinic acid, 2-phospho-1,2,4-tricarboxylic acid butane, benzotriazole, epoxy maleic acid-propylene ester-acrylamide-sulfonate multipolymer, disodium ethylenediaminetetraacetic acid and zinc sulfate monohydrate as solutes in a certain proportion.

[0032] Among them, polybutadiene acid is a high molecular weight polymer, and its molecular weight is generally between 400-800. It has good chemical stability and high temperature resistance, and its decomposition temperature is above 330℃. As a water treatment agent, it has excellent calcium carbonate inhibition performance. Compared with the common scale inhibitor polyacrylic acid, its scale inhibition performance is superior, which is due to the fact that it has more carboxyl groups on the polymer chain, and has stronger chelating ability with calcium, magnesium and other ions in the water body and lattice distortion ability; at the same time, it is low in price and still has the scale inhibition effect when used at higher temperatures, so it is widely used in circulating water cooling water systems and flash evaporation seawater desalination fields.

[0033] PBTCA (2-phospho-1,2,4-tricarboxylic acid butane) is a new generation of phosphine carboxylic acid invented in the 1980s. It is a relatively leading low-phosphorus corrosion and scale inhibitor and is now widely used in industrial production. PBTCA contains two functional groups, phosphate and carboxylic acid, which gives it excellent scale and corrosion inhibition properties. It can combine with calcium, magnesium and other ions in water to form a stable water-soluble complex, thereby effectively preventing the formation of scale. PBTCA also has good high temperature resistance, oxidation resistance, and chlorine resistance stability, and has good dispersibility for circulating water with high turbidity and high iron.

[0034] Benzotriazole (BTA) is a white crystalline powder, and its aqueous solution is weakly acidic. It is mainly used as a corrosion inhibitor for non-ferrous metals, and also has a corrosion inhibition effect on ferrous metals. It can generate stable metal salts with alkaline metals. It is usually used in combination with other water treatment agents, and the concentration is 1-3 mg / L. It is generally believed that the negative ions of BTA and non-ferrous metal ions form an insoluble and stable complex, which is adsorbed on the metal surface to form a protective film, thereby playing a role in corrosion inhibition.

[0035] Disodium ethylenediaminetetraacetate, also known as EDTA-2Na, is a good complexing agent in chemistry. The chemical formula is C 10 H 14 N2Na2O8, with a molecular weight of 336.206, has six coordinated atoms, and the complex formed is called a chelate. EDTA is often used in complexometric titration, generally to determine the content of metal ions. EDTA has important uses in industries such as dyes, food, and medicines. Disodium ethylenediaminetetraacetate is a tasteless, odorless or slightly salty white or milky white crystalline or granular powder, which is odorless and tasteless. It is soluble in water and extremely difficult to dissolve in ethanol. It is an important chelating agent that can chelate metal ions in the solution. It prevents discoloration, deterioration, turbidity, and oxidative loss of vitamin C caused by metals, and can also improve the antioxidant properties of oils and fats (trace metals in oils and fats, such as iron and copper, promote the oxidation of oils and fats).

[0036] Zinc sulfate monohydrate is an inorganic substance with the chemical formula ZnSO4·H2O. It appears as a white fluid powder. Density 3.28g / cm 3It is soluble in water, slightly soluble in alcohol, very easy to deliquesce in air, and insoluble in acetone. It is made by the reaction of zinc oxide or zinc hydroxide and sulfuric acid.

[0037] Embodiment 2:

[0038] This embodiment is further optimized on the basis of the above embodiment, and the same points as the above technical solution are not repeated here. In order to better realize the corrosion and scale inhibitor for reuse sewage system described in the present invention, the following setting mode is particularly adopted: the solute and solvent of the corrosion and scale inhibitor are composed of the following components by mass percentage:

[0039]

[0040] Embodiment 3:

[0041] This embodiment is further optimized on the basis of any of the above embodiments, and the same points as the above technical solutions are not repeated here. In order to better realize the corrosion and scale inhibitor for reuse sewage system described in the present invention, the following setting mode is particularly adopted: the solute and solvent of the corrosion and scale inhibitor are composed of the following components by mass percentage:

[0042]

[0043]

[0044] Embodiment 4:

[0045] This embodiment is further optimized on the basis of any of the above embodiments, and the same points as the above technical solutions are not repeated here. In order to better realize the corrosion and scale inhibitor for reuse sewage system described in the present invention, the following setting method is particularly adopted: the molecular formula of the epoxy maleic acid-propylene ester-acrylamide-sulfonate multi-polymer is: ((C3H3O2R)x-(C4H2O5)y-(C7H 13 O4NS)z), the relative molecular weight is between 8000-12000; epoxy maleic acid-propylene ester-acrylamide-sulfonate multipolymer is a multipolymer containing carboxyl, carbonyl, amide and sulfonic acid groups, with high dispersibility and scale inhibition performance. Compared with conventional acrylic acid-sulfonate co-dipolymer and maleic acid-acrylic acid dipolymer, it has more functional groups, is not monodisperse, has superior scale inhibition performance, and has good zinc stabilization and iron resistance.

[0046] Embodiment 5:

[0047] This embodiment is further optimized on the basis of any of the above embodiments, and the similarities with the above technical solutions are not repeated here. In order to better realize the corrosion inhibitor and scale inhibitor for reuse sewage system described in the present invention, the following setting is particularly adopted: the water is pure water.

[0048] Embodiment 6:

[0049] This embodiment is further optimized on the basis of any of the above embodiments, and the similarities with the above technical solutions are not repeated here. In order to better realize the corrosion and scale inhibitor for reuse sewage system described in the present invention, the following setting method is particularly adopted: the corrosion and scale inhibitor is added at a concentration of 50-100 mg / L when used as a corrosion and scale inhibitor; the corrosion and scale inhibitor is suitable for circulating water systems using Yangtze River water as make-up water, and is also suitable for circulating water systems using reuse sewage as make-up water; it is suitable for circulating water treatment with conductivity <5000us / cm and alkalinity + calcium hardness <1100mg / L, and the corrosion and scaling of carbon steel, stainless steel and copper equipment in the system are all controlled.

[0050] Embodiment 7:

[0051] This embodiment is further optimized on the basis of any of the above embodiments, and the similarities with the above technical solutions are not repeated here. In order to better realize the corrosion inhibitor and scale inhibitor for reused sewage system described in the present invention, the following setting is particularly adopted: Since the reused sewage has not been deeply treated, there are some periods of time when the conductivity, sulfate, chloride ion, total iron and other corrosive ions do not meet the water quality requirements of the circulating water system make-up water, and the water quality is harsh, so the corrosion performance requirements of the corrosion inhibitor and scale inhibitor are more stringent. In order to better realize the corrosion inhibitor and scale inhibitor for reused sewage system described in the present invention, the following setting is particularly adopted: the corrosion inhibitor and scale inhibitor is added to the circulating water body at a certain concentration (such as a concentration of 50 to 100 mg / L), which can combine with the ions in the water body to form a protective film on the surface of the equipment, effectively ensuring the stability of the equipment surface, and can alleviate the corrosion and scaling of the equipment.

[0052] Embodiment 8:

[0053] A corrosion inhibitor and scale inhibitor for a reuse sewage system comprises 100 parts by weight of a solute comprising 52 parts (the mass fractions of the raw materials in the solute are: 20 parts of polysuccinic acid, 10 parts of 2-phosphoryl-1,2,4-tricarboxylic acid butane, 2 parts of benzotriazole, 10 parts of epoxy maleic acid-propylene ester-acrylamide-sulfonate multipolymer, 5 parts of disodium ethylenediaminetetraacetate, and 5 parts of zinc sulfate monohydrate) and 48 parts of a solvent. The above components are uniformly mixed according to a proportion to obtain the corrosion inhibitor and scale inhibitor.

[0054] The corrosion and scale inhibitor performance of the corrosion and scale inhibitor of the present invention was measured in a laboratory, and the experiment was conducted at a concentration of 100 mg / L.

[0055] (I) Laboratory corrosion inhibition test

[0056] The water quality used for the corrosion inhibition experiment is shown in Table 1, and the laboratory corrosion inhibition test data is shown in Table 2.

[0057] Table 1 Water quality for corrosion inhibition experiment

[0058]

[0059] Table 2 Laboratory corrosion inhibition test

[0060]

[0061] Note: Enhanced corrosion inhibition is prepared by mixing recycled sewage and Yangtze River water in a ratio of 1:2 and concentrating it 4 times.

[0062] In 100% sewage, sulfate, chloride, alkalinity and conductivity exceeded the standard. After mixing with Yangtze River water at a ratio of 1:2, the alkalinity was greatly reduced, and the conductivity and sulfate were still exceeded. However, under the action of the corrosion and scale inhibitor of the present invention, whether in 100% sewage or 1:1, 1:2 water distribution, it showed excellent corrosion inhibition performance, indicating that by adding the corrosion and scale inhibitor of the present invention, the corrosion problem caused by the increase of ion concentration in sewage reuse can be effectively controlled (see the specific corrosion inhibition effect). Figure 1 , Figure 1 A is blank).

[0063] (II) Laboratory scale inhibition test

[0064] The data of the laboratory scale inhibition test (concentration method) are shown in Table 3.

[0065] Table 3 Laboratory scale inhibition test (concentration method)

[0066]

[0067] After the recycled water was concentrated 1.5 times (equivalent to 4.5 times the water concentration of 2:1 (Yangtze River water: recycled sewage)), the calcium inhibition rate of the formula was 100%, the phosphorus stabilization rate was 94.1%, and the zinc stabilization rate was still close to 80% when the alkalinity after the test was as high as 486mg / L. After strengthening the scaling conditions, the scale inhibition rate was slightly reduced, but the "calcium + alkalinity" content after the test reached 1045mg / L, and the scale inhibition effect of the formula was good (for specific scale inhibition effects, see Figure 2 , A is the blank effect diagram, and B is the effect diagram after adding medicine).

[0068] The corrosion and scale inhibitor of the present invention is actually applied to the circulating water system, controlling the concentration of organic phosphine in the agent to 2.5-3.5 mg / L; the system conductivity is less than 5000 us / cm, the calcium + total alkalinity is less than 1100 mg / L, and sewage is forced to be discharged when exceeding the control standard; the residual chlorine is greater than 0.2 mg / L.

[0069] The circulation system is replenished with water from the Yangtze River.

[0070] The water quality of the Yangtze River is shown in Table 4.

[0071] Table 4 Yangtze River water quality

[0072]

[0073] Circulation system replenishment water - reuse sewage.

[0074] The water quality of the recycled wastewater is shown in Table 5. The recycled wastewater has not been deeply treated, the water quality is unstable, and the water quality indicators (total alkalinity, total iron, sulfate, chloride ion) in some periods do not meet the requirements of Sinopec recycled water (Q / SH 0628.2-2014), which requires higher corrosion and scale inhibition performance of the corrosion and scale inhibitor in the present invention.

[0075] Table 5 Water quality of recycled wastewater

[0076]

[0077] The ratio of Yangtze River water to recycled sewage is 2:(1~2), and the total water replenishment volume is about 40~60m3 / h.

[0078] (III) The circulating water treatment effect after the implementation of the present invention.

[0079] Operating conditions of circulating water quality (as shown in Table 6.1 and Table 6.2).

[0080] After the implementation of the present invention, except for the high turbidity during the system slime stripping period, all water quality indicators in the remaining periods are within the control range required by Sinopec.

[0081] Table 6.1 Circulating water quality (A)

[0082]

[0083] Table 6.2 Circulating water quality (B)

[0084]

[0085] Monitor heat exchanger operation.

[0086] Combined with the heat exchanger scale monitoring data table shown in Table 7, after the implementation of the present invention, the corrosion rate and adhesion rate of the heat exchanger can be controlled. The corrosion rate of the carbon steel test tube is less than 0.075mm / a, the corrosion rate of the stainless steel test tube is less than 0.005mm / a, and the adhesion rate is less than 20mcm. The monitoring hanging piece only has corrosion at the hanging place, and the online instantaneous corrosion rate and fouling thermal resistance are both low. See the specific monitoring heat exchanger operation diagram for details. Figure 3 , the morphology of the monitoring coupon after treatment is shown in Figure 4 .

[0087] Table 7 Monitoring heat exchanger fouling data table

[0088]

[0089] Water cooler operation status.

[0090] Combination Figure 6 After the implementation of the present invention, 82% of the water coolers in the device have corrosion and scaling conditions of "level 1 + level 2" (specifically, the morphology of the open water side of the "level 1 + level 2" water cooler is shown in Figure 5 ), the corrosion and scaling of the "level 3 + level 4" water cooler are all reduced compared with the situation under the action of the original corrosion and scale inhibitor (the rating standard of water cooler refers to Q / SH 0725.3-2019), among which corrosion is reduced from 29% to 18%, and scaling is reduced from 8% to 6%. The corrosion and scale inhibition performance of the corrosion and scale inhibitor of the present invention is better than that of the original corrosion and scale inhibitor.

[0091] Water saving and emission reduction effect.

[0092] The implementation of the present invention enables the recycled sewage to replace 30% to 50% of fresh water to be added to the circulating water system. 3 / h, with a sewage recycling rate of 40%, the annual fresh water consumption can be reduced by 210,000 m 3 , correspondingly reducing the amount of sewage discharged by 210,000 m 3 . If the COD of sewage is 50mg / L, the annual COD discharge can be reduced by 10512kg, achieving the reduction of carbon emission at the source. The application of this invention to systems with similar water quality has more profound potential environmental protection and social significance.

[0093] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification or equivalent change made to the above embodiment based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A corrosion and scale inhibitor for a wastewater reuse system, characterized in that: The corrosion and scale inhibitor is prepared by mixing water as solvent, polysuccinic acid, 2-phosphoryl-1,2,4-tricarboxylic acid butane, benzotriazole, epoxy maleic acid-propylene ester-acrylamide-sulfonate multipolymer, disodium ethylenediaminetetraacetate and zinc sulfate monohydrate as solutes in a certain proportion.

2. The corrosion and scale inhibitor for a reuse sewage system according to claim 1, characterized in that: The solute and solvent of the corrosion and scale inhibitor are composed of the following components by mass percentage: The balance is water.

3. The corrosion and scale inhibitor for a reuse sewage system according to claim 2, characterized in that: The solute and solvent of the corrosion and scale inhibitor are composed of the following components by mass percentage: The balance is water.

4. A corrosion and scale inhibitor for a reuse sewage system according to claim 1, 2 or 3, characterized in that: The molecular formula of the epoxy maleic acid-propylene ester-acrylamide-sulfonate multipolymer is: ((C3H3O2R)x-(C4H2O5)y-(C7H 13 O4NS)z), the relative molecular weight is between 8000-12000.

5. A corrosion and scale inhibitor for a reuse sewage system according to claim 1, 2 or 3, characterized in that: The water used is pure water.

6. A corrosion and scale inhibitor for a reuse sewage system according to claim 1, 2 or 3, characterized in that: When the corrosion and scale inhibitor is used as a corrosion and scale inhibitor, the addition concentration is 50-100 mg / L.

7. A corrosion and scale inhibitor for a reuse sewage system according to claim 1, 2 or 3, characterized in that: The corrosion and scale inhibitor is added to the circulating water body at a certain concentration, and can combine with ions in the water body to form a protective film on the surface of the equipment.

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