An online anti-scaling and descaling agent for circulating water and preparation method thereof

Abstract

The present invention relates to an online anti-scaling and descaling agent for circulating water and a preparation method thereof, and belongs to the technical field of water treatment. The preparation method of the anti-scaling and descaling agent provided by the present invention is as follows: first, β-cyclodextrin-carbon quantum dots are prepared, and then some hydroxyls on the β-cyclodextrin are polymerized with acrylic acid and 2-acrylamide-2-methylpropanesulfonic acid; then, epichlorohydrin is used as a bridge to graft diethylenetriamine onto the remaining hydroxyls of β-cyclodextrin, and then 2-chloromalonic acid is substituted with the amine group on the diethylenetriamine. The anti-scaling and descaling agent prepared by the present invention has good water solubility and high temperature resistance, and contains a large number of carboxyl groups, sulfonic acid groups, amine groups and hydroxyls, and can be complexed with scale-forming ions to form a soluble complex, and has a strong complexing ability. At the same time, β-cyclodextrin can capture Ca 2+ Mg 2+ It enters its cavity, causing the inorganic salt scale lattice to be distorted, further preventing the formation of inorganic salt scale, and has a good effect in preventing and removing inorganic salt scale.

Description

Technical Field

[0001] The invention belongs to the technical field of water treatment, and in particular relates to an online anti-scaling and descaling agent for circulating water and a preparation method thereof. Background Art

[0002] Water shortage is an important factor restricting the sustainable development of refining and chemical enterprises. Water conservation and emission reduction have become important tasks for refining and chemical enterprises to solve development bottlenecks. Among them, the circulating water system is an important device for enterprises to achieve water conservation and emission reduction. Improving the concentration multiple of circulating water and recycling sewage circulating water system are common water-saving measures for enterprises. Scaling in the circulating water system has become an inevitable problem. Common scales include CaCO3, CaSO4, BaSO4, and SrSO4. At present, the conventional methods for removing scale are physical descaling and chemical descaling. Among them, the physical descaling method mainly includes electric pulse washing descaling, electromagnetic sweeping descaling and ultrasonic descaling, but the application range of physical descaling is small and the energy consumption is large; the chemical descaling method often uses the pickling method for descaling, but the acid is highly corrosive to the equipment, which affects the service life of the equipment. At the same time, pickling descaling often requires shutdown for cleaning, which seriously reduces the economic benefits, and the use temperature is low. Therefore, it is necessary to provide an online anti-scaling and descaling agent with excellent performance and green environmental protection. Summary of the invention

[0003] The purpose of the present invention is to provide an online anti-scaling and descaling agent for circulating water and a preparation method thereof. The anti-scaling and descaling agent prepared by the present invention has good water solubility and high temperature resistance, and contains a large number of carboxyl groups, sulfonic acid groups, amine groups and hydroxyl groups, which can form a soluble complex with scale-forming ions and have a strong complexing ability. At the same time, β-cyclodextrin can capture Ca 2+ Mg 2+ It enters its cavity, causing the inorganic salt scale lattice to be distorted, further preventing the formation of inorganic salt scale, and has a good effect in preventing and removing inorganic salt scale.

[0004] The technical problems to be solved by the present invention are as follows: the physical descaling method has a small application scope and high energy consumption; the chemical descaling method often uses the pickling method for descaling, but the acid is highly corrosive to the equipment, which affects the service life of the equipment. At the same time, pickling descaling often requires shutdown for cleaning, which seriously reduces the economic benefits, and the operating temperature is relatively low.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] An online anti-scaling and descaling agent for circulating water comprises the following components in weight fractions: 50-70 parts of an anti-scaling and descaling main agent, 0.1-1 parts of a penetrant, and 1-3 parts of a surfactant.

[0007] Furthermore, the preparation method of the anti-scaling and descaling agent comprises the following steps:

[0008] A1. Dissolve citric acid and β-cyclodextrin in deionized water, heat at 150-200°C for 25-34h, collect the supernatant by centrifugation after the reaction is completed, and then dialyze and freeze-dry to obtain β-cyclodextrin-carbon quantum dots;

[0009] Furthermore, in step A1, the usage ratio of citric acid, β-cyclodextrin and deionized water is (1.5-2) g: (3-6) g: (80-150) mL.

[0010] During the above operation, β-cyclodextrin is used as a passivating agent to modify carbon quantum dots to obtain β-cyclodextrin-carbon quantum dots. The β-cyclodextrin attached to the quantum dots can capture Ca 2+ Mg 2+ Entering its cavity, Ca 2+ Mg 2+ The lattices of CaCO3, CaSO4, and Mg(OH)2 formed by scaling are distorted, which further prevents the formation of CaCO3, CaSO4, and Mg(OH)2.

[0011] A2, add β-cyclodextrin-carbon quantum dots and 2-acrylamide-2-methylpropane sulfonic acid to deionized water, stir evenly, heat to 50-60°C, add acrylic acid and initiator, then heat to 70-80°C, stir for 1-2h, add sodium hydroxide solution, stir for 0.5-1h, filter, wash and dry to obtain 2-acrylamide-2-methylpropane sulfonic acid-acrylic acid-β-cyclodextrin-carbon quantum dot complex;

[0012] In the above-mentioned preparation process, part of the hydroxyl groups on the β-cyclodextrin structure on the β-cyclodextrin-carbon quantum dots undergo polymerization reaction with acrylic acid and 2-acrylamide-2-methylpropanesulfonic acid to obtain a 2-acrylamide-2-methylpropanesulfonic acid-acrylic acid-β-cyclodextrin-carbon quantum dot complex; the complex is deprotonated by sodium hydroxide solution, and the surface negative charge increases, so that the surface repulsion of the complex increases, and the 2-acrylamide-2-methylpropanesulfonic acid-acrylic acid-β-cyclodextrin-carbon quantum dot complex is more evenly dispersed and not easy to agglomerate, and the molecular structure is unfolded to further expose more active sites, thereby improving the anti-scaling and descaling ability, and at the same time facilitating the subsequent grafting of epichlorohydrin and 2-chloromalonic acid onto the complex. In addition, the polymerization reaction causes a large number of sulfonic acid groups to be contained in the molecular structure, which significantly improves the water solubility and high temperature resistance of the anti-scaling and descaling agent.

[0013] Furthermore, in step A2, the mass ratio of β-cyclodextrin-carbon quantum dots, 2-acrylamide-2-methylpropanesulfonic acid, acrylic acid and initiator is (33-37): (2.5-3.2): (11-15): (2.6-3.3).

[0014] Furthermore, in step A2, the initiator is at least one of ammonium persulfate or potassium persulfate.

[0015] A3. React 2-acrylamide-2-methylpropanesulfonic acid-acrylic acid-β-cyclodextrin-carbon quantum dot complex and epichlorohydrin under the catalysis of dodecylbenzenesulfonic acid to obtain intermediate 1; add diethylenetriamine to intermediate 1 to react to obtain intermediate 2; add 2-chloromalonic acid to intermediate 2 to react to obtain an anti-scaling and descaling main agent.

[0016] In the above preparation process, epichlorohydrin is used as a bridge to graft diethylenetriamine onto the remaining hydroxyl groups of β-cyclodextrin, and then 2-chloromalonic acid is substituted with the amine group on diethylenetriamine, thereby significantly increasing the content of carboxylic acid, hydroxyl and amino groups in the anti-scaling and descaling main agent, thereby significantly improving the complexing ability of the anti-scaling and descaling agent, allowing it to complex with more scale-forming cations, destroying the crystallization of inorganic salt scale, and greatly improving the anti-scaling and descaling efficiency.

[0017] Furthermore, in step A3, the mass ratio of 2-acrylamide-2-methylpropanesulfonic acid-acrylic acid-β-cyclodextrin-carbon quantum dot complex, epichlorohydrin, dodecylbenzenesulfonic acid, diethylenetriamine and 2-chloromalonic acid is (30-34): (3.2-3.8): (0.36-0.49): (2.5-3.7): (10.3-15.3).

[0018] Furthermore, in step A3, the 2-acrylamide-2-methylpropanesulfonic acid-acrylic acid-β-cyclodextrin-carbon quantum dot complex and epichlorohydrin are reacted under the catalysis of dodecylbenzenesulfonic acid for 2-5 hours at a reaction temperature of 90-130°C.

[0019] Furthermore, in step A3, diethylenetriamine is added to the intermediate 1 for a reaction time of 3-4 hours and a reaction temperature of 70-90°C.

[0020] Furthermore, in step A3, the reaction time of intermediate 2 and 2-chloromalonic acid is 2-4 hours, and the reaction temperature is 75-85°C.

[0021] The present invention also provides a method for preparing an online anti-scaling and descaling agent for circulating water, comprising the following steps:

[0022] The anti-scaling and descaling main agent, the penetrant and the surfactant are uniformly mixed to obtain an online anti-scaling and descaling agent for circulating water.

[0023] Furthermore, the penetrant is fatty alcohol polyoxyethylene ether.

[0024] Furthermore, the surfactant is at least one of dodecylbenzenesulfonic acid and polyethylene glycol monolaurate.

[0025] Beneficial effects of the present invention:

[0026] (1) In the technical solution of the present invention, the anti-scaling and descaling agent prepared has good water solubility and high temperature resistance, and contains a large number of carboxyl groups, sulfonic acid groups, amine groups and hydroxyl groups, which can form soluble complexes with scale-forming ions and have strong complexing ability. At the same time, β-cyclodextrin can capture Ca 2+ Mg 2+ It enters its cavity, causing the inorganic salt scale lattice to be distorted, further preventing the formation of inorganic salt scale, and has a good effect in preventing and removing inorganic salt scale.

[0027] (2) In the technical scheme of the present invention, β-cyclodextrin has good water solubility and excellent temperature resistance. In the present invention, it can be used as a passivator for nano-carbon quantum dots and a chelating agent for scale-forming cations. The formed β-cyclodextrin-carbon quantum dots have good anti-scaling and descaling performance. In order to further improve its water solubility and temperature resistance, the present invention polymerizes β-cyclodextrin with acrylic acid and 2-acrylamide-2-methylpropane sulfonic acid, thereby increasing the content of carboxyl and sulfonic acid groups on the anti-scaling and descaling agent. The increase in the carboxyl content further improves the anti-scaling and descaling effect. At the same time, in order to further improve the anti-scaling and descaling effects, epichlorohydrin is used as a bridge to graft diethylenetriamine onto the β-cyclodextrin molecular chain, and then 2-chloromalonic acid is substituted with multiple amine groups on diethylenetriamine, which significantly increases the content of carboxyl, hydroxyl and amino groups in the anti-scaling and descaling main agent, thereby significantly improving the complexing ability of the anti-scaling and descaling agent, and can chelate with more scale-forming cations, destroying the crystallization of inorganic salt scale, and greatly improving the anti-scaling and descaling efficiency.

[0028] (3) In the technical solution of the present invention, the anti-scaling and descaling effect of the anti-scaling and descaling agent is significantly improved through the combined action of the anti-scaling and descaling main agent, the penetrant and the surfactant.

[0029] (4) In the technical solution of the present invention, the prepared anti-scaling and descaling agent has a high fluorescence intensity, and the concentration of the anti-scaling and descaling agent can be monitored online. DETAILED DESCRIPTION

[0030] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] Example 1

[0032] This embodiment provides a method for preparing an anti-scaling and descaling agent, comprising the following steps:

[0033] A1. Dissolve 15 g of citric acid and 30 g of β-cyclodextrin in 800 mL of deionized water, heat at 150 ° C for 25 h, collect the supernatant by centrifugation after the reaction is completed, and then dialyze and freeze-dry to obtain β-cyclodextrin-carbon quantum dots;

[0034] A2, 33g β-cyclodextrin-carbon quantum dots and 2.5g 2-acrylamide-2-methylpropanesulfonic acid were added to 80mL deionized water, stirred evenly, heated to 50°C, 11g acrylic acid and 2.6g ammonium persulfate were added, and then heated to 70°C, stirred for 1h, and then 2mol / L sodium hydroxide solution was added, stirred for 0.5h, so that 20% of the carboxyl groups were protonated, filtered, washed, and dried to obtain 2-acrylamide-2-methylpropanesulfonic acid-acrylic acid-β-cyclodextrin-carbon quantum dot complex;

[0035] A3. Put 30g of 2-acrylamide-2-methylpropanesulfonic acid-acrylic acid-β-cyclodextrin-carbon quantum dot complex into 70mL deionized water, stir and dissolve, then add 3.2g of epichlorohydrin and 0.36g of dodecylbenzenesulfonic acid, react at 90°C for 2h to obtain intermediate 1; add 2.5g of diethylenetriamine to intermediate 1, react at 70°C for 3h to obtain intermediate 2; add 10.3g of 2-chloromalonic acid and 7.2g of triethylamine to intermediate 2, react at 75°C for 2h, filter, wash and dry to obtain the anti-scaling and descaling main agent.

[0036] Example 2

[0037] This embodiment provides a method for preparing an anti-scaling and descaling agent, comprising the following steps:

[0038] A1. Dissolve 17 g of citric acid and 42 g of β-cyclodextrin in 1000 mL of deionized water, heat at 170° C. for 29 h, centrifuge and collect the supernatant after the reaction is completed, dialyze and freeze-dry to obtain β-cyclodextrin-carbon quantum dots;

[0039] A2, 35g β-cyclodextrin-carbon quantum dots and 2.8g 2-acrylamide-2-methylpropanesulfonic acid were added to 80mL deionized water, stirred evenly, heated to 55°C, 13g acrylic acid and 2.9g ammonium persulfate were added, and then heated to 75°C, stirred for 1.5h, and then 2mol / L sodium hydroxide solution was added, stirred for 1h, so that 30% of the carboxyl groups were protonated, filtered, washed, and dried to obtain 2-acrylamide-2-methylpropanesulfonic acid-acrylic acid-β-cyclodextrin-carbon quantum dot complex;

[0040] A3. Put 32g of 2-acrylamide-2-methylpropanesulfonic acid-acrylic acid-β-cyclodextrin-carbon quantum dot complex into 75mL deionized water, stir and dissolve, then add 3.5g of epichlorohydrin and 0.41g of dodecylbenzenesulfonic acid, react at 110°C for 3h to obtain intermediate 1; add 3.1g of diethylenetriamine to intermediate 1, react at 80°C for 3h to obtain intermediate 2; add 12.7g of 2-chloromalonic acid and 7.6g of triethylamine to intermediate 2, react at 80°C for 3h, filter, wash and dry to obtain the anti-scaling and descaling main agent.

[0041] Comparative Example 1

[0042] Compared with Example 2, the anti-scaling and descaling main agent of Comparative Example 1 did not perform steps A2 and A3 operations, and the other steps and raw materials were the same as those of Example 2.

[0043] Comparative Example 2

[0044] Compared with Example 2, the anti-scaling and descaling main agent of Comparative Example 2 did not perform step A3 operation, and the other steps and raw materials were the same as those of Example 2.

[0045] Comparative Example 3

[0046] Compared with Example 2, the anti-scaling and descaling main agent of Comparative Example 3 did not perform step A2 operation, and the 2-acrylamide-2-methylpropanesulfonic acid-acrylic acid-β-cyclodextrin-carbon quantum dots composite in step A3 was replaced by β-cyclodextrin-carbon quantum dots, and the other steps and raw materials were synchronized with Example 2.

[0047] Example 3

[0048] This embodiment provides a method for preparing an anti-scaling and descaling agent, comprising the following steps:

[0049] A1. Dissolve 18 g of citric acid and 50 g of β-cyclodextrin in 1100 mL of deionized water, heat at 180 ° C for 32 h, collect the supernatant by centrifugation after the reaction is completed, and then dialyze and freeze-dry to obtain β-cyclodextrin-carbon quantum dots;

[0050] A2, 36g β-cyclodextrin-carbon quantum dots and 2.9g 2-acrylamide-2-methylpropane sulfonic acid were added to 90mL deionized water, stirred evenly, heated to 55°C, 14g acrylic acid and 3.1g potassium persulfate were added, and then heated to 75°C, stirred for 1.5h, and then 2mol / L sodium hydroxide solution was added, stirred for 1h, so that 30% of the carboxyl groups were protonated, filtered, washed, and dried to obtain 2-acrylamide-2-methylpropane sulfonic acid-acrylic acid-β-cyclodextrin-carbon quantum dot complex;

[0051] A3. Put 33g of 2-acrylamide-2-methylpropanesulfonic acid-acrylic acid-β-cyclodextrin-carbon quantum dot complex into 80mL deionized water, stir and dissolve, then add 3.6g of epichlorohydrin and 0.43g of dodecylbenzenesulfonic acid, react at 120°C for 4h to obtain intermediate 1; add 3.4g of diethylenetriamine to intermediate 1, react at 80°C for 4h to obtain intermediate 2; add 14.3g of 2-chloromalonic acid and 7.9g of triethylamine to intermediate 2, react at 80°C for 3h, filter, wash and dry to obtain the anti-scaling and descaling main agent.

[0052] Example 4

[0053] This embodiment provides a method for preparing an anti-scaling and descaling agent, comprising the following steps:

[0054] A1. Dissolve 20 g of citric acid and 60 g of β-cyclodextrin in 1500 mL of deionized water, heat at 200 °C for 34 h, collect the supernatant by centrifugation after the reaction is completed, and then dialyze and freeze-dry to obtain β-cyclodextrin-carbon quantum dots;

[0055] A2, 37g β-cyclodextrin-carbon quantum dots and 3.2g 2-acrylamide-2-methylpropane sulfonic acid were added to 80mL deionized water, stirred evenly, heated to 60°C, 15g acrylic acid and 3.3g potassium persulfate were added, and then heated to 80°C, stirred for 2h, and then 2mol / L sodium hydroxide solution was added, stirred for 1h, so that 20% of the carboxyl groups were protonated, filtered, washed, and dried to obtain 2-acrylamide-2-methylpropane sulfonic acid-acrylic acid-β-cyclodextrin-carbon quantum dot complex;

[0056] A3. Put 34g of 2-acrylamide-2-methylpropanesulfonic acid-acrylic acid-β-cyclodextrin-carbon quantum dot complex into 80mL deionized water, stir and dissolve, then add 3.8g of epichlorohydrin and 0.49g of dodecylbenzenesulfonic acid, react at 130°C for 5h to obtain intermediate 1; add 3.7g of diethylenetriamine to intermediate 1, react at 90°C for 4h to obtain intermediate 2; add 15.3g of 2-chloromalonic acid and 7.2g of triethylamine to intermediate 2, react at 85°C for 4h, filter, wash and dry to obtain the anti-scaling and descaling main agent.

[0057] Example 5

[0058] An online anti-scaling and descaling agent for circulating water comprises the following components in weight fractions: 50 parts of the anti-scaling and descaling main agent prepared in Example 1, 0.1 parts of fatty alcohol polyoxyethylene ether, and 1 part of dodecylbenzene sulfonic acid.

[0059] The preparation method of the online anti-scaling and descaling agent for circulating water comprises the following steps:

[0060] The components are weighed according to the above weight fractions, and the anti-scaling and descaling main agent, the penetrant and the surfactant are evenly mixed to obtain an online anti-scaling and descaling agent for circulating water.

[0061] Example 6

[0062] An online anti-scaling and descaling agent for circulating water comprises the following components in weight fractions: 60 parts of the anti-scaling and descaling main agent prepared in Example 2, 0.6 parts of fatty alcohol polyoxyethylene ether, and 2 parts of dodecylbenzene sulfonic acid.

[0063] The preparation method of the online anti-scaling and descaling agent for circulating water comprises the following steps:

[0064] The components are weighed according to the above weight fractions, and the anti-scaling and descaling main agent, the penetrant and the surfactant are evenly mixed to obtain an online anti-scaling and descaling agent for circulating water.

[0065] Example 7

[0066] An online anti-scaling and descaling agent for circulating water comprises the following components in weight fractions: 66 parts of the anti-scaling and descaling main agent prepared in Example 3, 0.7 parts of fatty alcohol polyoxyethylene ether, and 2.4 parts of polyethylene glycol monolaurate.

[0067] The preparation method of the online anti-scaling and descaling agent for circulating water comprises the following steps:

[0068] The components are weighed according to the above weight fractions, and the anti-scaling and descaling main agent, the penetrant and the surfactant are evenly mixed to obtain an online anti-scaling and descaling agent for circulating water.

[0069] Example 8

[0070] An online anti-scaling and descaling agent for circulating water comprises the following components in weight fractions: 70 parts of the anti-scaling and descaling main agent prepared in Example 4, 1 part of fatty alcohol polyoxyethylene ether, and 3 parts of polyethylene glycol monolaurate.

[0071] The preparation method of the online anti-scaling and descaling agent for circulating water comprises the following steps:

[0072] The components are weighed according to the above weight fractions, and the anti-scaling and descaling main agent, the penetrant and the surfactant are evenly mixed to obtain an online anti-scaling and descaling agent for circulating water.

[0073] Comparative Example 4

[0074] Compared with Example 6, the anti-scaling and descaling main agent of Comparative Example 4 is the anti-scaling and descaling main agent prepared in Comparative Example 1, and the other steps and raw materials are the same as those of Example 6.

[0075] Comparative Example 5

[0076] Compared with Example 6, the anti-scaling and descaling main agent of Comparative Example 5 is the anti-scaling and descaling main agent prepared in Comparative Example 2, and the other steps and raw materials are the same as those of Example 6.

[0077] Comparative Example 6

[0078] Compared with Example 6, the anti-scaling and descaling main agent of Comparative Example 6 is the anti-scaling and descaling main agent prepared in Comparative Example 3, and the other steps and raw materials are the same as those of Example 6.

[0079] Performance Testing

[0080] The anti-scaling and descaling agents prepared in Examples 5-8 and Comparative Examples 4-6 were tested for their performance, and the results are shown in Table 1.

[0081] (1) Descaling performance test:

[0082] a. Static descaling test: dissolve 10g of anti-scaling and descaling agent in 50mL of tap water, add 2g of calcium carbonate or calcium sulfate, stir evenly and place at 80℃ for 24h, then calculate the descaling rate.

[0083] b. Dynamic descaling test: Test water: Ca 2+ The mass concentration is 317 mg / L, the total hardness is 437 mg / L, the total alkalinity is 362 mg / L, the chloride ion mass concentration is 118 mg / L, and the pH is 7.5, of which Ca 2+ , total alkalinity and total hardness are all measured in terms of CaCO3. Making scale samples: Dry, weigh and measure the volume of the 20# seamless carbon steel pipe with chrome plating on the outer wall, and then put it into the dynamic simulation test device of circulating cooling water for scaling. The scaling conditions are: steam temperature 100℃, flow rate in the test tube 0.5m / s, inlet temperature 30℃, run for 5 days without sewage discharge, and weigh after drying. Cleaning: Use a dynamic simulation test device to clean the scale sample, control the steam temperature at 100℃, the inlet temperature at 30℃, and the flow rate in the test tube at 0.5m / s, then add test water and a scale-preventing and descaling agent with a concentration of 10mg / L to the scale sample in turn, replace the sewage in the test tube with tap water after cleaning for 48h, then remove the test tube and dry, weigh and measure the volume, and calculate the descaling rate.

[0084] (2) Scale inhibition performance test:

[0085] a. Static scale inhibition test: refer to GB / T 16632-2019 "Determination of scale inhibition performance of water treatment agents - calcium carbonate deposition method" for the test. Test conditions: Ca 2+ The mass concentration is 300 mg / L, HCO3 - The mass concentration of is 915mg / L, the concentration of anti-scaling and descaling agent is 10mg / L, and the temperature is kept constant at 80℃ water bath for 10h;

[0086] b. Dynamic scale inhibition test: refer to HG / T 2160-2008 "Cooling Water Dynamic Simulation Test Method" for dynamic simulation experiment. Test conditions: the concentration of scale inhibitor is 10mg / L, the test tube is made of 20# carbon steel, seamless, the inner diameter is 0.019m, the length is 1.050m, the test raw water is Ca 2+ The mass concentration is 342 mg / L, the total hardness is 437 mg / L, the total alkalinity is 331 mg / L, the chloride ion mass concentration is 132 mg / L, and the pH is 7.7, of which Ca 2+ , total alkalinity and total hardness are all calculated as CaCO3, the concentration multiple is 5 times, the flow rate is 1.0m / L, the inlet and outlet temperatures of the circulating water are 32℃, and the operation time is 20d.

[0087] (3) Temperature resistance test: refer to GB / T 16632-2019 "Determination of scale inhibition performance of water treatment agents - calcium carbonate deposition method" for testing. Test conditions: Ca 2+ The mass concentration is 300 mg / L (in terms of Ca 2+ ), HCO3 - The mass concentration is 915 mg / L, the concentration of anti-scaling and descaling agent is 10 mg / L, and the temperature is maintained at 150℃ water bath for 10 hours.

[0088] Table 1

[0089]

[0090] It can be seen from the data in Table 1 that the scale-preventing and descaling agent prepared by the present invention can effectively remove calcium sulfate and calcium carbonate, has excellent scale-preventing effect under both static and dynamic conditions, and has good high temperature resistance. It can be seen from the data of Comparative Example 6 and Comparative Example 4 that since the β-cyclodextrin-carbon quantum dots did not perform steps A2 and A3, the content of carboxyl, amine and sulfonic acid groups decreased significantly, resulting in a significant decrease in its scale-preventing and descaling efficiency, and a decrease in temperature resistance. It can be seen from the data of Comparative Example 6 and Comparative Example 5 that due to the absence of grafted diethylenetriamine and 2-chloropropionic acid, the scale-preventing and descaling efficiency decreased significantly. It can be seen from the data of Comparative Example 6 and Comparative Example 6 that due to the absence of grafted sulfonic acid groups, the temperature resistance decreased significantly.

[0091] In the description of the specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0092] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the invention or exceed the scope defined by the claims, they shall all fall within the protection scope of the present invention.

Claims

1. An online anti-scaling and descaling agent for circulating water, characterized in that: The invention comprises the following components in parts by weight: 50-70 parts of anti-scaling and descaling main agent, 0.1-1 parts of penetrant, and 1-3 parts of surfactant; The method for preparing the anti-scaling and descaling agent comprises the following steps: A1. Dissolve citric acid and β-cyclodextrin in deionized water, heat at 150-200°C for 25-34h, collect the supernatant by centrifugation after the reaction is completed, and then dialyze and freeze-dry to obtain β-cyclodextrin-carbon quantum dots; A2, add β-cyclodextrin-carbon quantum dots and 2-acrylamide-2-methylpropane sulfonic acid to deionized water, stir evenly, heat to 50-60°C, add acrylic acid and initiator, then heat to 70-80°C, stir for 1-2h, add sodium hydroxide solution, stir for 0.5-1h, filter, wash and dry to obtain 2-acrylamide-2-methylpropane sulfonic acid-acrylic acid-β-cyclodextrin-carbon quantum dot complex; A3. React 2-acrylamide-2-methylpropanesulfonic acid-acrylic acid-β-cyclodextrin-carbon quantum dot complex and epichlorohydrin under the catalysis of dodecylbenzenesulfonic acid to obtain intermediate 1; add diethylenetriamine to intermediate 1 to react to obtain intermediate 2; add 2-chloromalonic acid and triethylamine to intermediate 2 to react to obtain an anti-scaling and descaling main agent.

2. The online anti-scaling and descaling agent for circulating water according to claim 1, characterized in that: In the step A1, the usage ratio of citric acid, β-cyclodextrin and deionized water is (1.5-2) g: (3-6) g: (80-150) mL.

3. The online anti-scaling and descaling agent for circulating water according to claim 1, characterized in that: In the step A2, the mass ratio of β-cyclodextrin-carbon quantum dots, 2-acrylamide-2-methylpropanesulfonic acid, acrylic acid and initiator is (33-37): (2.5-3.2): (11-15): (2.6-3.3).

4. The online anti-scaling and descaling agent for circulating water according to claim 1, characterized in that: In the step A2, the initiator is at least one of ammonium persulfate or potassium persulfate.

5. The online anti-scaling and descaling agent for circulating water according to claim 1, characterized in that: In the step A3, the mass ratio of 2-acrylamide-2-methylpropanesulfonic acid-acrylic acid-β-cyclodextrin-carbon quantum dot complex, epichlorohydrin, dodecylbenzenesulfonic acid, diethylenetriamine and 2-chloromalonic acid is (30-34): (3.2-3.8): (0.36-0.49): (2.5-3.7): (10.3-15.3).

6. The online anti-scaling and descaling agent for circulating water according to claim 1, characterized in that: In the step A3, the 2-acrylamide-2-methylpropanesulfonic acid-acrylic acid-β-cyclodextrin-carbon quantum dot complex and epichlorohydrin are reacted under the catalysis of dodecylbenzenesulfonic acid for 2-5 hours at a reaction temperature of 90-130°C.

7. The online anti-scaling and descaling agent for circulating water according to claim 1, characterized in that: In the step A3, diethylenetriamine is added to the intermediate 1 for a reaction time of 3-4 hours at a reaction temperature of 70-90°C.

8. The online anti-scaling and descaling agent for circulating water according to claim 1, characterized in that: In the step A3, the reaction time of the intermediate 2 and 2-chloromalonic acid is 2-4 hours, and the reaction temperature is 75-85°C.

9. A method for preparing an online anti-scaling and descaling agent for circulating water according to any one of claims 1 to 8, characterized in that: The following steps are involved: The anti-scaling and descaling main agent, the penetrant and the surfactant are uniformly mixed to obtain an online anti-scaling and descaling agent for circulating water.

10. The method for preparing an online anti-scaling and descaling agent for circulating water according to claim 9, characterized in that: The penetrant is fatty alcohol polyoxyethylene ether; the surfactant is at least one of dodecylbenzenesulfonic acid and polyethylene glycol monolaurate.

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