Crystal dissolving agent for tunnel drainage system as well as preparation method and application of crystal dissolving agent

Abstract

The invention belongs to the technical field of drainage pipeline cleaning, and particularly relates to a tunnel drainage system crystal dissolving agent and a preparation method and application thereof. The crystal dissolving agent is composed of composite acid, a chelating agent, a foaming agent and a corrosion inhibitor. The composite acid contains sulfamic acid, citric acid and oxalic acid and can quickly dissolve calcium carbonate crystals and generate an easy-to-wash product; the chelating agent is ethylene diamine tetraacetic acid disodium salt and nitrilotriacetic acid sodium salt, and metal ion interference can be inhibited; the foaming agent is sodium dodecyl sulfate and sodium alpha-olefin sulfonate, so that the cleaning coverage range can be expanded; the corrosion inhibitor is at least two of sodium silicate, sodium phosphate and ammonium chloride, and can form a composite protective film to reduce the corrosion of acid liquor. Through the synergistic effect of multiple components, the crystal dissolving agent has the functions of efficient descaling and pipeline protection. Orthogonal tests show that the calcium carbonate removal rate of the crystal dissolving agent in the optimal proportion is up to 75%. The crystal dissolving agent has the advantages of simple preparation process, environment-friendly and safe raw materials and low volatility, and is suitable for chemical descaling maintenance of tunnel engineering drainage pipelines.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of sewer cleaning, and particularly relates to a tunnel drainage system crystal dissolving agent and a preparation method and application thereof. BACKGROUND

[0002] In tunnel engineering, drainage pipes are key facilities for ensuring the safety and stable operation of tunnel structures. Due to long-term transportation of underground water or rainwater containing silt, minerals, microorganisms and organic matter, the inner wall of the pipe is prone to depositing scale and other dirt. These deposits will gradually block the pipe, reduce the drainage efficiency, and even cause safety hazards such as tunnel leakage and lining corrosion.

[0003] At present, the methods for removing scale from tunnel drainage pipes mainly include mechanical dredging, high-pressure water jet cleaning and chemical cleaning. Mechanical dredging and high-pressure water jet cleaning can remove some hard dirt, but have limited effect on strongly adherent chemical deposits (such as calcium carbonate), and may damage the inner wall of the pipe. Chemical cleaning dissolves dirt by using acid and alkali, but traditional crystal dissolving agents (such as hydrochloric acid and sodium hydroxide) have strong corrosiveness, and agents with excessively high acidity or alkalinity can easily corrode concrete or metal pipes, shorten the service life of the facilities, and may also pollute underground water, and volatile components may endanger the health of workers in the tunnel closed environment. SUMMARY

[0004] In view of the above deficiencies of the prior art, the present application aims to provide a novel tunnel drainage system crystal dissolving agent. The crystal dissolving agent can effectively remove calcium carbonate dirt in the tunnel drainage pipe in all directions through the synergistic effect of composite acid and various additives, while having low corrosiveness and operational safety, and achieving efficient and comprehensive removal of calcium carbonate crystalline blockage in the tunnel drainage system.

[0005] To solve the above technical problems, the present application adopts the following technical solution: The first object of the present application is to provide a tunnel drainage system crystal dissolving agent composed of composite acid, chelating agent, foaming agent and corrosion inhibitor, and the mass percentage of each raw material is as follows: composite acid: 65%~69%, chelating agent: 12%~13%, foaming agent: 12%~14%, corrosion inhibitor: 8%~9%, and the total is 100%.

[0006] The composite acid is a mixture of aminosulfonic acid, citric acid and oxalic acid.

[0007] In a preferred embodiment of the present application, the mass ratio of aminosulfonic acid, citric acid and oxalic acid is 7.6~10.5:3.6~2:1.

[0008] In a preferred embodiment of the present application, the chelating agent is composed of ethylenediaminetetraacetic acid disodium and sodium nitrilotriacetate in a mass ratio of 1:0.4~0.625.

[0009] In the preferred embodiment of the present application, the foaming agent is a mixture of sodium dodecyl sulfonate and sodium alpha-olefin sulfonate, and the mass ratio of sodium dodecyl sulfonate to sodium alpha-olefin sulfonate is 3-4:1.

[0010] In the preferred embodiment of the present application, the corrosion inhibitor comprises at least two of sodium silicate, sodium phosphate, and ammonium chloride, and the mass ratio of any two components is 1:0.8-1.25.

[0011] In the preferred embodiment of the present application, the corrosion inhibitor comprises at least two of sodium silicate, sodium phosphate, and ammonium chloride, and the mass ratio of any two components is 1:0.8-1.25.

[0012] The second object of the present application is to provide a preparation method of a tunnel drainage system crystal dissolving agent, comprising the following steps: S1, according to the mass percentage of each raw material, the following components are weighed: composite acid 65%-69%, chelating agent 12%-13%, foaming agent 12%-14%, corrosion inhibitor 8%-9%, and the total is 100%.

[0013] S2, the weighed composite acid, chelating agent, foaming agent and corrosion inhibitor are mixed and stirred at room temperature until uniform to obtain a tunnel drainage system crystal dissolving agent.

[0014] The third object of the present application is to provide the use of the tunnel drainage system crystal dissolving agent described above for removing calcium carbonate crystalline substances.

[0015] Compared with the prior art, the present application has the beneficial effects that: 1. The present application provides a tunnel drainage system crystal dissolving agent with high-efficiency scale removal performance. The composite acid is a mixture of aminosulfonic acid, citric acid and oxalic acid. Aminosulfonic acid reacts with calcium carbonate to form a soluble calcium salt with low corrosion; citric acid dissolves scale through acid-base neutralization and forms a protective film on the metal surface; oxalic acid quickly removes stubborn scale layers due to its strong acidity, and the generated calcium oxalate flocs are easy to flush away. The synergistic effect of the three makes the calcium carbonate removal efficiency significantly better than that of a single acid system, and effectively reduces the corrosion of the pipeline and steel bars.

[0016] 2. The corrosion inhibitor (sodium silicate + sodium phosphate / ammonium chloride) used in the present application forms a dense protective film (such as a siliceous film and a passivation film) on the surface of the pipeline and steel bars, isolates the acid liquid from erosion, adjusts the pH value of the solution, maintains the acid-base balance, reduces the corrosion risk, and ensures the structural safety and integrity of the tunnel drainage system.

[0017] 3、The application adopts sodium dodecyl sulfonate and sodium alpha-olefin sulfonate as the foaming agent, rich bubbles are generated to fill the pipeline, so that the crystal dissolving agent fully contacts the inner wall of the pipeline, and no dead angle cleaning is realized, especially for the dirt on the side of the pipeline which is not often watered.

[0018] 4、The composite acid used in the application has low volatility, and combined with protective measures, the safety of the operator can be effectively guaranteed, especially for closed environments such as tunnels. The raw materials used have no toxic components, the waste liquid treatment cost is low, the stable complex formed by the chelating agent and metal ions can reduce heavy metal migration pollution, and is environmentally friendly.

[0019] 5、The tunnel drainage system crystal dissolving agent prepared by the application has low raw material cost and is easy to obtain. The preparation process is simple and can be completed by stirring at room temperature without the need for complex equipment and special process, which is suitable for industrial production and on-site application, reduces the production threshold and cost. The generated foam can cover the whole surface of the pipeline, realize no dead angle cleaning, reduce the amount of reagent, and further reduce the use cost.

[0020] 6、Through L27 (3 9 ) orthogonal test optimization, the high efficiency and reliability of the crystal dissolving agent prepared by the application are verified. The experimental results show that the crystal dissolving agent with the optimal ratio can achieve a high removal rate within 6h, and has good repeatability and high stability. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 The figure shows the calcium carbonate removal rate of the tunnel drainage crystal dissolving agent prepared by the application examples 1~application examples 5 and the comparative examples 1~comparative examples 3. DETAILED DESCRIPTION

[0022] The following describes the technical solutions in the application examples in conjunction with preferred examples, and it is obvious that the described examples are only part of the application examples, not all the examples. Based on the examples in the application, all other examples obtained by those skilled in the art without creative labor are within the scope of protection of the application.

[0023] It should be noted that all the professional terms used in the application are only for the purpose of describing the specific examples, and are not intended to limit the protection scope of the application. Unless otherwise specified, all the raw materials, reagents, instruments and equipment used in the following examples of the application can be purchased from the market or prepared by the existing method.

[0024] Currently, the methods for removing scale in tunnel drainage pipeline mainly include mechanical dredging, high-pressure water jet cleaning and chemical cleaning. Although mechanical dredging and high-pressure water jet cleaning can remove some hard scale, they have limited effect on chemical deposits (such as calcium carbonate) with strong adhesion, and may damage the inner wall of the pipeline. Chemical cleaning dissolves scale by using acid or alkali, but traditional crystal dissolving agents (such as hydrochloric acid and sodium hydroxide) have strong corrosiveness, and agents with excessively high acidity or alkalinity can easily corrode concrete or metal pipelines, shorten the service life of the facilities, and may also pollute groundwater, and volatile components may endanger the health of workers in the tunnel enclosed environment.

[0025] Based on this, in one aspect, the present application provides a tunnel drainage system crystal dissolving agent, which is composed of composite acid, chelating agent, foaming agent and corrosion inhibitor. The mass percentage of each raw material is as follows: composite acid: 65%~69%, chelating agent: 12%~13%, foaming agent: 12%~14%, corrosion inhibitor: 8%~9%, and the total is 100%. Among them, the composite acid is a mixture of sulfamic acid, citric acid and oxalic acid.

[0026] It should be noted that in the present application, the composite acid is a key component for removing insoluble calcium carbonate crystals in the tunnel drainage system, which is a mixture of sulfamic acid, citric acid and oxalic acid. Sulfamic acid reacts with calcium carbonate to form a soluble calcium salt, which has low corrosiveness and causes little damage to the pipeline and steel bars. Citric acid dissolves scale through acid-base neutralization reaction to form citrate, which is easily soluble in water. At the same time, citric acid can form a protective film on the metal surface to reduce the corrosion of acid on the metal. Oxalic acid has strong acidity and can quickly break down stubborn scale layers, and the generated calcium oxalate floc is easily washed away. In addition, oxalic acid can also form stable complexes with metal ions, inhibit the hydrolysis of metal ions, and reduce the possibility of metal corrosion. The synergistic effect of the three acids makes the scale removal efficiency significantly better than that of a single acid system, while reducing the corrosion risk to the pipeline and steel bars.

[0027] The chelating agent is a mixture of disodium ethylenediaminetetraacetate and sodium nitrilotriacetate, and the mass ratio is 1:0.4~0.625. Disodium ethylenediaminetetraacetate has multiple coordination atoms in its molecule, which can form stable ring-shaped chelates with metal ions, wrapping the metal ions inside the chelate to destroy the structure of calcium carbonate and promote its dissolution. The amino and carboxyl groups in the molecule of sodium nitrilotriacetate can also form coordination bonds with metal ions, further enhancing the chelation effect. The synergistic effect of the two can effectively inhibit the interference of metal ions, improve the scale removal efficiency, and reduce the hydrolysis and corrosion of metal ions.

[0028] The foaming agent is mixed by sodium dodecyl sulfonate and sodium alpha-olefin sulfonate. Sodium dodecyl sulfonate has good foaming performance and can produce abundant and persistent foam; sodium alpha-olefin sulfonate further enhances the stability of the foam, so that the foam can cover the inner wall of the pipeline for a long time. The foam produced by the mixture of the two can fill the pipeline, so that the crystal dissolving agent can fully contact each part of the inner wall of the pipeline, especially the dirt on the side that is not often watered, thereby realizing dead angle-free cleaning.

[0029] The corrosion inhibitor is mixed by at least two of sodium silicate, sodium phosphate, and ammonium chloride. The synergistic effects are as follows: sodium silicate can form a dense siliceous protective film on the surface of the pipeline and steel bars, effectively isolating the acid solution from the metal. Sodium phosphate forms a composite protective film by synergistic effect with sodium silicate, further enhancing the protection of the metal. At the same time, sodium phosphate has a certain alkalinity, which can adjust the pH value of the solution, maintain the acid-base balance, and reduce the corrosion risk. The chloride ion in ammonium chloride can inhibit the anodic dissolution process of the metal and slow down the corrosion rate. The corrosion inhibitor significantly reduces the corrosion of the acid solution on the pipeline and steel bars by forming a composite protective film and adjusting the pH value of the solution, ensuring the structural safety and integrity of the tunnel drainage system.

[0030] The synergistic effect of the composite acid, chelating agent, foaming agent, and corrosion inhibitor enables the crystal dissolving agent of the present application to efficiently remove dirt while maximizing the protection of the pipeline and steel bars and reducing the corrosion risk. The rapid dissolution of calcium carbonate crystals by the composite acid, the inhibition of metal ion interference by the chelating agent, and the expansion of the cleaning coverage by the foaming agent significantly improve the dirt removal efficiency. The combined action of aminosulfonic acid and citric acid in the composite acid, sodium silicate, sodium phosphate, and ammonium chloride in the corrosion inhibitor forms a multi-layer protective film, effectively isolating the acid solution from the metal and reducing the corrosion risk. The composite acid has low volatility, the chelating agent reduces heavy metal migration pollution, the raw materials have no toxic ingredients, and the waste liquid treatment cost is low, ensuring the safety of the operating personnel and environmental friendliness. Through this synergistic effect, the crystal dissolving agent of the present application not only realizes efficient dirt removal, but also significantly improves the service life and safety of the pipeline.

[0031] In another aspect, the present application provides a preparation method of a tunnel drainage system crystal dissolving agent, comprising the following steps: S1. According to the mass percentage of each raw material, the composite acid is 65% to 69%, the chelating agent is 12% to 13%, the foaming agent is 12% to 14%, and the corrosion inhibitor is 8% to 9%, totaling 100%.

[0032] S2. The weighed composite acid, chelating agent, foaming agent, and corrosion inhibitor are mixed and stirred at room temperature until uniform to obtain the tunnel drainage system crystal dissolving agent.

[0033] It should be noted that the whole preparation process is simple and fast, suitable for large-scale industrial production. The raw material and equipment cost is low, which effectively reduces the production cost. The reaction at room temperature, low volatility and no toxic ingredients reduce the impact on the environment. The operation and storage process is safe, which ensures the safety of personnel and equipment during production. Therefore, the preparation method of the application is not only simple and efficient, but also low in cost, stable in quality, environmentally friendly, strong in adaptability and high in safety, which provides an ideal solution for the production of tunnel drainage system crystal dissolving agent.

[0034] Finally, the application provides an application of the tunnel drainage system crystal dissolving agent in removing calcium carbonate crystals.

[0035] The optimal ratio of the prepared crystal dissolving agent can achieve a high removal rate within 6h, and has good repeatability and high stability.

[0036] The following is further illustrated by specific examples.

[0037] Example 1 A tunnel drainage system crystal dissolving agent is composed of composite acid, chelating agent, foaming agent and corrosion inhibitor, wherein the composite acid is composed of sulfamic acid, citric acid and oxalic acid, the chelating agent is composed of disodium ethylenediaminetetraacetate and sodium nitrilotriacetate, the foaming agent is composed of sodium dodecyl sulfonate and sodium alpha-olefin sulfonate, and the corrosion inhibitor is composed of sodium silicate and sodium phosphate. The mass percentage of each raw material is: sulfamic acid 44%, citric acid 13%, oxalic acid 9%, sodium dodecyl sulfonate 9%, sodium alpha-olefin sulfonate 4%, disodium ethylenediaminetetraacetate 6%, sodium nitrilotriacetate 6%, sodium silicate 5% and sodium phosphate 4%, and the total is 100%.

[0038] The preparation method of the tunnel drainage system crystal dissolving agent comprises the following steps: S1, according to the mass percentage of each raw material, sulfamic acid 44%, citric acid 13%, oxalic acid 9%, sodium dodecyl sulfonate 9%, sodium alpha-olefin sulfonate 4%, disodium ethylenediaminetetraacetate 6%, sodium nitrilotriacetate 6%, sodium silicate 5% and sodium phosphate 4%, and the total is 100%.

[0039] S2, the composite acid, chelating agent, foaming agent and corrosion inhibitor are mixed and stirred at a speed of 1000 revolutions per minute at room temperature for 10 minutes until uniform, to obtain the tunnel drainage system crystal dissolving agent.

[0040] Example 2 A tunnel drainage system crystal dissolving agent is composed of composite acid, chelating agent, foaming agent and corrosion inhibitor, wherein the composite acid is composed of sulfamic acid, citric acid and oxalic acid, the chelating agent is composed of disodium ethylenediaminetetraacetate and sodium nitrilotriacetate, the foaming agent is composed of sodium dodecyl sulfonate and sodium alpha-olefin sulfonate, and the corrosion inhibitor is composed of sodium silicate and ammonium chloride. The mass percentage of each raw material is as follows: sulfamic acid 47%, citric acid 12%, oxalic acid 9%, sodium dodecyl sulfonate 9%, alpha-olefin sulfonate 3%, disodium ethylenediaminetetraacetate 6%, sodium nitrilotriacetate 6%, sodium silicate 4% and ammonium chloride 4%, and the total is 100%.

[0041] The preparation method of the tunnel drainage system crystal dissolving agent comprises the following steps: S1, according to the mass percentage of each raw material, sulfamic acid 47%, citric acid 12%, oxalic acid 9%, sodium dodecyl sulfonate 9%, alpha-olefin sulfonate 3%, disodium ethylenediaminetetraacetate 6%, sodium nitrilotriacetate 6%, sodium silicate 4% and ammonium chloride 4% are weighed, and the total is 100%.

[0042] S2, the weighed composite acid, chelating agent, foaming agent and corrosion inhibitor are fully mixed and stirred at a speed of 1000 revolutions per minute at room temperature for 10 minutes until uniform, to obtain the tunnel drainage system crystal dissolving agent.

[0043] Example 3 A tunnel drainage system crystal dissolving agent is composed of composite acid, chelating agent, foaming agent and corrosion inhibitor, wherein the composite acid is composed of sulfamic acid, citric acid and oxalic acid, the chelating agent is composed of disodium ethylenediaminetetraacetate and sodium nitrilotriacetate, the foaming agent is composed of sodium dodecyl sulfonate and sodium alpha-olefin sulfonate, and the corrosion inhibitor is composed of sodium silicate and ammonium chloride. The mass percentage of each raw material is as follows: sulfamic acid 49%, citric acid 11%, oxalic acid 8%, sodium dodecyl sulfonate 9%, alpha-olefin sulfonate 3%, disodium ethylenediaminetetraacetate 6%, sodium nitrilotriacetate 6%, sodium silicate 4% and ammonium chloride 4%, and the total is 100%.

[0044] The preparation method of the tunnel drainage system crystal dissolving agent comprises the following steps: S1, according to the mass percentage of each raw material, sulfamic acid 49%, citric acid 11%, oxalic acid 8%, sodium dodecyl sulfonate 9%, alpha-olefin sulfonate 3%, disodium ethylenediaminetetraacetate 6%, sodium nitrilotriacetate 6%, sodium silicate 4% and ammonium chloride 4% are weighed, and the total is 100%.

[0045] S2, the weighed composite acid, chelating agent, foaming agent and corrosion inhibitor are fully mixed and stirred at a speed of 1000 revolutions per minute at room temperature for 10 minutes until uniform, to obtain the tunnel drainage system crystal dissolving agent.

[0046] Example 4 A tunnel drainage system crystal dissolving agent is composed of composite acid, chelating agent, foaming agent and corrosion inhibitor, wherein the composite acid is composed of sulfamic acid, citric acid and oxalic acid, the chelating agent is composed of disodium ethylenediaminetetraacetate and sodium nitrilotriacetate, the foaming agent is composed of sodium dodecyl sulfonate and sodium alpha-olefin sulfonate, and the corrosion inhibitor is composed of sodium silicate and ammonium chloride. The mass percentage of each raw material is as follows: sulfamic acid 44%, citric acid 13%, oxalic acid 10%, sodium dodecyl sulfonate 10%, alpha-olefin sulfonate 3%, disodium ethylenediaminetetraacetate 6%, sodium nitrilotriacetate 6%, sodium silicate 4%, and ammonium chloride 4%, and the total is 100%.

[0047] The preparation method of the tunnel drainage system crystal dissolving agent comprises the following steps: S1, according to the mass percentage of each raw material, sulfamic acid 44%, citric acid 13%, oxalic acid 10%, sodium dodecyl sulfonate 10%, alpha-olefin sulfonate 3%, disodium ethylenediaminetetraacetate 6%, sodium nitrilotriacetate 6%, sodium silicate 4%, and ammonium chloride 4% are weighed, and the total is 100%.

[0048] S2, the weighed composite acid, chelating agent, foaming agent and corrosion inhibitor are fully mixed and stirred at a speed of 1000 revolutions per minute at room temperature for 10 minutes until uniform, to obtain the tunnel drainage system crystal dissolving agent.

[0049] Example 5 A tunnel drainage system crystal dissolving agent is composed of composite acid, chelating agent, foaming agent and corrosion inhibitor, wherein the composite acid is composed of sulfamic acid, citric acid and oxalic acid, the chelating agent is composed of disodium ethylenediaminetetraacetate and sodium nitrilotriacetate, the foaming agent is composed of sodium dodecyl sulfonate and sodium alpha-olefin sulfonate, and the corrosion inhibitor is composed of sodium silicate and ammonium chloride. The mass percentage of each raw material is as follows: sulfamic acid 44%, citric acid 13%, oxalic acid 10%, sodium dodecyl sulfonate 10%, alpha-olefin sulfonate 3%, disodium ethylenediaminetetraacetate 6%, sodium nitrilotriacetate 6%, sodium silicate 4%, and ammonium chloride 4%, and the total is 100%.

[0050] The preparation method of the tunnel drainage system crystal dissolving agent comprises the following steps: S1, according to the mass percentage of each raw material, sulfamic acid 44%, citric acid 13%, oxalic acid 10%, sodium dodecyl sulfonate 10%, alpha-olefin sulfonate 3%, disodium ethylenediaminetetraacetate 6%, sodium nitrilotriacetate 6%, sodium silicate 4%, and ammonium chloride 4% are weighed, and the total is 100%.

[0051] S2, the weighed composite acid, chelating agent, foaming agent and corrosion inhibitor are fully mixed and stirred at a speed of 1000 revolutions per minute at room temperature for 10 minutes until uniform, to obtain the tunnel drainage system crystal dissolving agent.

[0052] Comparative Example 1 A tunnel drainage system crystal dissolving agent is composed of acid, chelating agent, foaming agent and corrosion inhibitor. The acid is sulfamic acid, the chelating agent is composed of disodium ethylenediaminetetraacetate and sodium nitrilotriacetate, the foaming agent is composed of sodium dodecyl sulfonate and sodium alpha-olefin sulfonate, and the corrosion inhibitor is composed of sodium silicate and sodium phosphate. The mass percentage of each raw material is as follows: sulfamic acid 56%, sodium dodecyl sulfonate 12%, sodium alpha-olefin sulfonate 4%, disodium ethylenediaminetetraacetate 8%, sodium nitrilotriacetate 8%, sodium silicate 7% and sodium phosphate 5%, and the total is 100%.

[0053] The preparation method of the tunnel drainage system crystal dissolving agent comprises the following steps: S1, according to the mass percentage of each raw material, sulfamic acid 56%, sodium dodecyl sulfonate 12%, sodium alpha-olefin sulfonate 4%, disodium ethylenediaminetetraacetate 8%, sodium nitrilotriacetate 8%, sodium silicate 7% and sodium phosphate 5% are weighed, and the total is 100%.

[0054] S2, the weighed sulfamic acid, chelating agent, foaming agent and corrosion inhibitor are fully mixed and stirred at a speed of 1000 rpm at room temperature for 10 minutes until uniform, to obtain the tunnel drainage system crystal dissolving agent.

[0055] Comparative Example 2 A tunnel drainage system crystal dissolving agent is composed of sulfamic acid and oxalic acid. The mass percentage of each raw material is as follows: sulfamic acid 70% and oxalic acid 30%, and the total is 100%.

[0056] The preparation method of the tunnel drainage system crystal dissolving agent comprises the following steps: S1, according to the mass percentage of each raw material, sulfamic acid 70% and oxalic acid 30% are weighed, and the total is 100%.

[0057] S2, the weighed sulfamic acid and oxalic acid are fully mixed and stirred at a speed of 1000 rpm at room temperature for 10 minutes until uniform, to obtain the tunnel drainage system crystal dissolving agent.

[0058] Comparative Example 3 A tunnel drainage system crystal dissolving agent is composed of sulfamic acid and citric acid. The mass percentage of each raw material is as follows: sulfamic acid 60% and citric acid 40%, and the total is 100%.

[0059] The preparation method of the tunnel drainage system crystal dissolving agent comprises the following steps: S1, according to the mass percentage of each raw material, sulfamic acid 60% and citric acid 40% are weighed, and the total is 100%.

[0060] S2, the weighed sulfamic acid and citric acid are fully mixed and stirred at a speed of 1000 rpm at room temperature for 10 minutes until uniform, to obtain the tunnel drainage system crystal dissolving agent.

[0061] The removal rate of calcium carbonate of the tunnel drainage system crystallization inhibitor prepared in Examples 1-5 and Comparative Examples 1-3 is tested. The testing method of the removal rate of calcium carbonate includes the following steps:

[0062] S1, 150mL of pure water is added into a 500mL beaker, and the weight is measured.

[0063] S2, 4g of calcium carbonate powder is weighed and poured into the beaker, and shaken uniformly.

[0064] S3, according to the component raw materials of Examples 1-5 and Comparative Examples 1-3, the raw materials of the tunnel drainage system crystallization inhibitor are weighed and mixed, and the total weight of the components is measured.

[0065] S4, the mixed crystallization inhibitor is poured into the beaker, and the time is started, and the weight is measured every certain time, and the weight is measured three times.

[0066] S5, the removal rate of calcium carbonate is calculated.

[0067] Figure 1 The removal rates of Examples 1-5 and Comparative Examples 1-3 are compared. As shown in the figure, Figure 1 It can be seen that the removal rate of calcium carbonate of the crystallization inhibitor prepared in Example 1 is as high as 75% within 6h, while the removal rate of calcium carbonate of the crystallization inhibitor prepared by using a single acid agent or two kinds of acid composite is less than 50%. This shows that the tunnel drainage system crystallization inhibitor prepared in Example 1 has the best calcium carbonate removal effect.

[0068] The L27(3 9 ) orthogonal table is used for orthogonal test to investigate the factors affecting the descaling efficiency, and the optimal crystallization inhibitor preparation scheme is obtained. The factors affecting the descaling efficiency are the contents of aminosulfonic acid, oxalic acid, citric acid, disodium ethylenediaminetetraacetate (EDTA), sodium nitrilotriacetate, sodium dodecyl sulfonate, sodium alpha-olefin sulfonate, sodium silicate and sodium phosphate. In the preparation process of the tunnel drainage system crystallization inhibitor, 27 test combinations are designed, and each factor is investigated at 3 levels as shown in Table 1.

[0069] Table 1 Factors and levels In the 27 test processes, the test of the removal rate of calcium carbonate includes the following steps: S1, 150mL of pure water is added into a 500mL beaker, and the weight is measured.

[0070] S2, 4g of calcium carbonate powder is weighed and poured into the beaker, and shaken uniformly.

[0071] S3, according to the test scheme, nine different components of raw materials were weighed and mixed, and the total weight was measured.

[0072] S4, the mixed crystallization agent was poured into a beaker, and the time was started. The weight was measured every certain time, and a total of three times.

[0073] S5, the calcium carbonate removal rate was calculated.

[0074] Through the above test, the orthogonal test result table, i.e. Table 2, was obtained. According to Table 2, taking the 6h removal rate as an index, by comparing the k values of different levels of each factor, the optimal ratio of the tunnel drainage system crystallization agent was finally determined as follows: 7g of sulfamic acid; 2g of citric acid; 1.5g of oxalic acid; 1.5g of sodium dodecyl sulfonate; 0.5g of α-olefin sulfonate sodium; 1g of ethylenediaminetetraacetic acid disodium; 1g of nitrilotriacetic acid sodium; 0.8g of sodium silicate; and 0.6g of sodium phosphate. The ratio is the component ratio of the crystallization agent of Example 1.

[0075] Table 2 Orthogonal test results In order to verify the corrosion effect of the crystallization agent of Example 1 and the crystallization agent of Comparative Example 1 on the double-wall corrugated pipe and the steel bar below the double-wall corrugated pipe, double-wall corrugated pipes and steel bars with initial masses of 9.72g and 12.07g respectively were selected, two groups of corresponding crystallization agent solutions were configured, the double-wall corrugated pipes and the steel bars were respectively placed in the crystallization agent solutions, and the immersion time was 1d, 3d, 7d and 28d. The masses of the double-wall corrugated pipes and the steel bars at different immersion times are shown in Table 3.

[0076] Table 3 Masses of double-wall corrugated pipes and steel bars after immersion in the crystallization agents of Example 1 and Comparative Example 1 From Table 3, it can be seen that the mass of the double-wall corrugated pipe after immersion in the crystallization agent changes under the conditions of Comparative Example 1 and Example 1. The mass of the double-wall corrugated pipe of Example 1 is relatively stable; while the mass of Comparative Example 1 shows a continuous slow downward trend, which indicates that the corrosion inhibitor added in Example 1 slows down the corrosion effect of the crystallization agent on the double-wall corrugated pipe. The mass of the steel bar gradually decreases under the two conditions as the immersion time increases, and the mass of the steel bar of Comparative Example 1 decreases more, which indicates that the corrosion of the steel bar is reduced in Example 1 with the addition of the corrosion inhibitor.

[0077] It is to be understood that every range of values disclosed herein is to be understood to encompass any and every sub-range of values within the range. Although the preferred embodiments of the invention have been described above, it will be appreciated that those skilled in the art, on consideration of this disclosure, will be able to devise additional embodiments that, although not explicitly described or shown herein, nonetheless fall within the scope of the present invention. Accordingly, the appended claims are intended to embrace all such alternatives, modifications and variations of the preferred embodiments of the invention, as falling within the scope of the present invention.

[0078] Obviously, numerous modifications and variations of the present application are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the present application can be practiced otherwise than as specifically described herein.

Claims

1. A tunnel drainage system crystallization inhibitor characterized by, The compound acid, the chelating agent, the foaming agent and the corrosion inhibitor are composed, and the mass percentage of each raw material is as follows: the compound acid is 65-69%, the chelating agent is 12-13%, the foaming agent is 12-14%, and the corrosion inhibitor is 8-9%, and the total is 100%. The compound acid is composed of aminosulfonic acid, citric acid and oxalic acid.

2. The tunnel drainage system crystallization inhibitor according to claim 1, characterized in that, The mass ratio of aminosulfonic acid, citric acid and oxalic acid is 7.6-10.5:2-3.6:

1.

3. The tunnel drainage system crystallization inhibitor according to claim 1, characterized in that, The chelating agent is composed of disodium ethylenediaminetetraacetate and sodium nitrilotriacetate, and the mass ratio is 1:0.4-0.

625.

4. The tunnel drainage system crystallization inhibitor according to claim 1, wherein The foaming agent is composed of sodium dodecyl sulfonate and sodium alpha-olefin sulfonate, and the mass ratio is 3-4:

1.

5. The tunnel drainage system crystallization inhibitor of claim 1, wherein The corrosion inhibitor contains at least two of sodium silicate, sodium phosphate and ammonium chloride, and the mass ratio of any two components is 1:0.8-1.

25.

6. The tunnel drainage system crystallization inhibitor of claim 1, wherein The compound acid, the chelating agent, the foaming agent and the corrosion inhibitor are composed, and the mass percentage of each raw material is as follows: the compound acid is 65-69%, the chelating agent is 12-13%, the foaming agent is 12-14%, and the corrosion inhibitor is 8-9%, and the total is 100%.

7. A method of preparing the tunnel drainage system crystallization inhibitor according to any one of claims 1 to 6, characterized by, The method comprises the following steps: According to the mass percentage of each raw material, the compound acid is 65-69%, the chelating agent is 12-13%, the foaming agent is 12-14%, and the corrosion inhibitor is 8-9%, and the total is 100%. The compound acid, the chelating agent, the foaming agent and the corrosion inhibitor are composed, and the mass percentage of each raw material is as follows: the compound acid is 65-69%, the chelating agent is 12-13%, the foaming agent is 12-14%, and the corrosion inhibitor is 8-9%, and the total is 100%.

8. The application of the tunnel drainage system crystal dissolving agent in claim 1-6 for removing calcium carbonate crystals.

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