Efficient descaling agent and preparation method thereof

Abstract

The invention provides an efficient descaling agent and a preparation method thereof. The scale remover comprises the following components: 10 wt% to 15 wt% of trifluoroacetic acid, 2 wt% to 5 wt% of deoxycholic acid, 1 wt% to 3 wt% of isothiocyanate, 1.5 wt% to 3.5 wt% of furfuryl thioformate, 14 wt% to 18 wt% of hazelnut shell powder, 20 wt% to 30 wt% of ethanol and the balance of water. The scale remover can remove a scale layer with relatively strong adhesive force on the surface of equipment, has high removal efficiency on iron oxides, silicon oxides, silicate, calcium magnesium salts and the like, and does not corrode the surface of the equipment.

Description

Technical Field

[0001] The present invention belongs to the field of equipment descaling and cleaning, and particularly relates to an efficient scale inhibitor and a preparation method thereof. Background Art

[0002] In the petrochemical field, considering various influencing factors such as cost, heat exchange effect, and operation convenience, open-circuit circulating water is usually used as a refrigerant to cool equipment such as heat exchangers and jacketed kettles. Although the open-circuit circulating water is controlled by adding chemicals such as corrosion and scale inhibitors, the management levels of each manufacturer vary, and the source of the open-circuit circulating water is ordinary industrial water, with relatively high contents of calcium and magnesium ions, impurities, etc. Coupled with the non-closed system, dust and other sundries in the air are easily introduced into the system, resulting in a high content of system impurities. When the circulating water containing calcium and magnesium ions and various impurities flows through the heat exchange equipment, due to the influence of factors such as temperature and flow rate, it deposits and adheres to the wall surface of the heat exchange equipment. Long-term operation leads to a decline in the heat exchange effect, and it is necessary to regularly clean the circulating water side of the heat exchange equipment.

[0003] Currently, in the industry, strong acids such as hydrochloric acid, sulfamic acid, and citric acid are usually used, combined with corrosion inhibitors and other components to compound cleaning agents for chemical cleaning, but there are the following problems: First, after using strong acids, the scale cleaning effect is guaranteed, but it corrodes the equipment matrix, affecting the service life of the equipment; second, using weak acids or adjusting the pH to weak acidity, combined with the action of corrosion inhibitors, can reduce equipment damage, but the cleaning effect on scale layers with strong adhesion is limited; third, most scale inhibitors require hot cleaning and a long cleaning time, which leads to an enhanced corrosion effect on metals, and at the same time, the increase in temperature will cause the volatilization of acids, increasing the safety risk during the descaling process; fourth, the corrosion inhibition components are usually conventional corrosion inhibitors, such as benzotriazole and hexamethylenetetramine, and there is less application of green corrosion inhibitors, which is not safe and environmentally friendly enough.

[0004] CN104058512B discloses a boiler rapid scale inhibitor and a preparation method thereof, which is compounded with components such as sodium polyacrylate, sodium triethanolamine sulfonate, triethanolamine, glacial acetic acid, trisodium phosphate, hexametaphosphate, aniline, and N-alkylsulfonic acid aminoacetic acid. This method descales at 50 - 60 °C. Due to its weak acidity, this method has a good effect on removing calcium and magnesium salts, but has limited effect on removing scale layers with strong adhesion (such as iron oxides, silicon oxides, and silicates).

[0005] CN110684983A discloses a neutral scale inhibitor and a preparation method thereof, which is compounded with components such as aminobenzoic acid, aminobenzenesulfonic acid, benzotriazole, and pH regulators. Due to the neutral system of this method, it has limited effect on removing scale layers with strong adhesion (such as iron oxides, silicon oxides, and silicates).

[0006] CN101186395B discloses a composite acid scale inhibitor and its preparation method, which is prepared by compounding propionic acid, citric acid, aminosulfonic acid, hydrochloric acid, phosphoric acid, ammonium chloride, and ammonium sulfate. This method is mainly used to remove scale (calcium and magnesium salts), and the system is acidic as a whole without adding corrosion inhibitors, which may cause corrosion to the equipment body.

[0007] In summary, there is an urgent need in the art for a highly efficient scale inhibitor with strong scale removal ability, high efficiency, green corrosion inhibition, and good corrosion inhibition effect. Summary of the Invention

[0008] One of the objectives of the present invention is to provide a highly efficient scale inhibitor. The scale inhibitor can remove the scale layer with strong adhesion on the equipment surface, such as iron oxides, silicon oxides, silicates, calcium and magnesium salts, etc., with high removal efficiency and without corroding the equipment surface.

[0009] To achieve the above objective, the technical solution adopted by the present invention is as follows:

[0010] A highly efficient scale inhibitor, the scale inhibitor contains the following components: 10wt%-15wt% trifluoroacetic acid, 2wt%-5wt% deoxycholic acid, 1wt%-3wt% isothiocyanate, 1.5wt%-3.5wt% furfuryl thiocarbonate, 14wt%-18wt% hazelnut shell powder, 20wt%-30wt% ethanol, and the rest is water.

[0011] In one embodiment of the present invention, the isothiocyanate is one or more of methyl isothiocyanate, ethyl isothiocyanate, and allyl isothiocyanate.

[0012] In the present invention, the trifluoroacetic acid can be trifluoroacetic acid with a content greater than 99%, the deoxycholic acid can be deoxycholic acid with a content greater than 98%, the furfuryl thiocarbonate can be furfuryl thiocarbonate with a content greater than 98%, and the ethanol can be ethanol with a content greater than 99%.

[0013] Another objective of the present invention is to provide a method for preparing a scale inhibitor.

[0014] A method for preparing a scale inhibitor, the scale inhibitor is the above-mentioned scale inhibitor, and the method is: mixing ethanol and water, adding trifluoroacetic acid, deoxycholic acid, isothiocyanate, and furfuryl thiocarbonate and mixing, adding hazelnut shell powder, performing ultrasonic treatment, centrifuging, and the obtained supernatant is the target scale inhibitor.

[0015] In one embodiment of the present invention, the hazelnut shell powder is surface-removed, ground into powder by a grinder after drying at 40°C - 80°C for 10 - 24h; preferably, the particle size of the hazelnut shell powder is 10 - 600 mesh.

[0016] In one embodiment of the present invention, the ultrasonic treatment is ultrasonic stirring in a water bath at 10°C - 40°C for 0.5 - 1 h, and the ultrasonic power is 100W - 200W.

[0017] Another object of the present invention is to provide a method for using a descaling agent.

[0018] A method for using a descaling agent, wherein the descaling agent is the above-mentioned descaling agent or the descaling agent prepared by the above method, and the descaling temperature in the using method is 10°C - 40°C, and the descaling time is 1 h - 3 h.

[0019] Still another object of the present invention is to provide a use for preparing a high-efficiency descaling agent.

[0020] A use for preparing a high-efficiency descaling agent, wherein the descaling agent is the above-mentioned descaling agent or the descaling agent prepared by the above method, and the descaling agent is used for descaling in the petrochemical field.

[0021] In the present invention, due to the strong electron-withdrawing property of -CF 3 , trifluoroacetic acid has strong acidity, strong solubility in calcium and magnesium salts, silicates, and iron oxides, and promotes the dissolution of the scale layer. On the one hand, the salts generated by the dissolution of trifluoroacetic acid and the scale layer accelerate the penetration of the scale layer, promote the loosening and dispersion of the scale layer, and cooperate with its strong acidity to accelerate the dissolution of the scale layer; on the other hand, it will adhere to the metal surface and undergo a complexation reaction with metal ions to form a dense, hydrophobic, and stable chelate, slowing down the corrosion of the equipment matrix.

[0022] Deoxycholic acid has a proportional cooperation effect with trifluoroacetic acid, enhancing the acidity of trifluoroacetic acid and promoting the dissolution of the scale layer; the salts generated by the reaction of deoxycholic acid and the scale layer can act as a surfactant to accelerate the loosening and dispersion of the scale layer.

[0023] Isothiocyanate can undergo partial hydrolysis under acidic conditions to generate isothiocyanic acid. Isothiocyanic acid cooperates with trifluoroacetic acid and deoxycholic acid to accelerate the dissolution and penetration of the scale layer; isothiocyanate can promote the dispersion and loosening of the scale layer and accelerate dissolution; the reaction product of isothiocyanic acid and the scale layer can adhere to the equipment surface in the form of a dense film to prevent further corrosion.

[0024] Furfuryl thiocarbonate mainly cooperates with the reaction products of deoxycholic acid and the scale layer and isothiocyanate, making the scale layer disperse and loosen at an extremely fast speed, increasing the contact area between acidic substances and the scale layer, thereby accelerating the dissolution of the scale layer.

[0025] Hazelnut shells contain different phenolic acid compounds such as gallic acid, chlorogenic acid, protocatechuic acid, catechuic acid, etc., and various flavonoid compounds such as flavonoids and isoflavones. At the same time, they contain various sugar components such as mannose, rhamnose, glucose, galactose, xylose, and arabinose. The proportional mixture of trifluoroacetic acid and terephthalic acid has a good extraction effect on phenolic acids, flavonoids, and polysaccharide compounds in hazelnut shells, enabling as much of the above substances as possible to be extracted into the solution. There are various active groups in the above phenolic acids, flavonoids, and polysaccharide compounds, which can act as multi-functional ligands to undergo complexation reactions with metal ions to form stable chelates, complementing the chelate film produced by the above trifluoroacetate salts and further delaying corrosion. In addition, the proportional mixture of trifluoroacetic acid and deoxycholic acid can hydrolyze some polysaccharides into monosaccharides. During the process of dissolving the scale layer, the monosaccharides will be converted into monosaccharide salts with better chelating performance, thereby delaying corrosion. The corrosion inhibition effect of the descaling agent is mainly provided by trifluoroacetate salts, isothiocyanates, phenolic acids, flavonoids, polysaccharides in hazelnut shells, and the converted monosaccharide salts.

[0026] Compared with the prior art, the present invention has the following positive effects:

[0027] (1) It has extremely strong solubility in the strongly adherent scale layer on the surface of metal equipment, such as iron oxides, silicon oxides, silicates, calcium and magnesium salts, etc., and can achieve the evacuation and dissolution of the scale layer at low temperature and in a short time.

[0028] (2) It has extremely low corrosion to metal equipment, and can achieve a corrosion inhibition efficiency of more than 97% for carbon steel materials and more than 98% for stainless steel materials.

[0029] (3) The descaling agent uses hazelnut shells as raw materials to achieve the corrosion inhibition effect, with low cost, no heavy metals, and is green and environmentally friendly. Specific Embodiments

[0030] The following further illustrates the present invention through specific embodiments. The embodiments described in the present invention are only for the purpose of explaining the present invention and do not limit the scope of the present invention.

[0031] In the following embodiments of the present invention, the descaling effect of the descaling agent is characterized by the descaling rate (N).

[0032] N=(M / M0)*100%

[0033] Wherein:

[0034] N - descaling rate, %;

[0035] M - the amount of scale washed off, g;

[0036] M0 - the original amount of scale before cleaning, g.

[0037] During the chemical cleaning process, the corrosion condition of the equipment is expressed by the corrosion rate (V), with the unit of g / m2 / h, and the corrosion inhibition effect of the corrosion inhibitor is expressed by the corrosion inhibition efficiency (η), with the unit of %.

[0038] V=△m / (t*s)*100%

[0039] in:

[0040] V-corrosion rate, g / m2 / h;

[0041] △m-weight of metal corroded, g;

[0042] t-time for metal to be corroded, h;

[0043] s-the area of ​​contact between metal and descaling agent, m2;

[0044] η=(V0-V1) / V0*100%;

[0045] Wherein, η is the corrosion inhibition efficiency, unitless;

[0046] V0 is the corrosion rate under the action of the descaling agent without corrosion inhibitor, g / m2 / h;

[0047] V1 is the corrosion rate under the action of the descaling agent containing corrosion inhibitor, g / m2 / h.

[0048] Trifluoroacetic acid: Aladdin manufacturer, chromatographic grade, purity ≥ 99.5%

[0049] Deoxycholic acid: Aladdin manufacturer, analytical standard grade, purity > 99%

[0050] Isothiocyanate: methyl isothiocyanate, Aladdin manufacturer, analytical grade, purity>98%; ethyl isothiocyanate, Aladdin manufacturer, GC grade, purity>95%; allyl isothiocyanate, Aladdin manufacturer, analytical grade, purity>95%

[0051] Furfuryl thioformate: Aladdin manufacturer, analytical grade, purity > 98%

[0052] Ethanol: Aladdin manufacturer, chromatography grade, purity 99.8%

[0053] Grinding machine: Xuxin Shengke manufacturer, model ST-M200

[0054] Particle size analyzer: Dandong Bater manufacturer, Batersize 2000 model

[0055] Ultrasound: Shangyi manufacturer, SN-QX-08E.

[0056] Example 1

[0057] The scale inhibitor contains the following components: 15 wt% trifluoroacetic acid, 5 wt% deoxycholic acid, 3 wt% methyl isothiocyanate, 3.5 wt% furfuryl thiocarbonate, 18 wt% hazelnut shell powder, 20 wt% ethanol, and the balance is water.

[0058] Weigh 100 g of ethanol and 177.5 g of water and mix them evenly. Then add 75 g of trifluoroacetic acid, 25 g of deoxycholic acid, 15 g of methyl isothiocyanate, and 17.5 g of furfuryl thiocarbonate in sequence and mix them evenly. Select hazelnut shells, remove the surface impurities, place them in a constant-temperature drying oven at 80 °C for 10 h to obtain a dried sample. Put the dried hazelnut shells into a grinder and grind them into a powder with a mesh size of 15. Weigh 90 g of hazelnut shell powder and put it into the above-prepared mixed solution, place it in a 40 °C water bath and stir it ultrasonically for 0.5 h with an ultrasonic power of 200 W. Centrifuge for 10 min and select the supernatant to obtain a highly efficient scale inhibitor.

[0059] Example 2

[0060] The scale inhibitor contains the following components: 10 wt% trifluoroacetic acid, 2 wt% deoxycholic acid, 1 wt% methyl isothiocyanate, 1.5 wt% furfuryl thiocarbonate, 14 wt% hazelnut shell powder, 30 wt% ethanol, and the balance is water.

[0061] Weigh 150 g of ethanol and 207.5 g of water and mix them evenly. Then add 50 g of trifluoroacetic acid, 10 g of deoxycholic acid, 5 g of methyl isothiocyanate, and 7.5 g of furfuryl thiocarbonate in sequence and mix them evenly. Select hazelnut shells, remove the surface impurities, place them in a constant-temperature drying oven at 40 °C for 24 h to obtain a dried sample. Put the dried hazelnut shells into a grinder and grind them into a powder with a mesh size of 600. Weigh 70 g of hazelnut shell powder and put it into the above-prepared mixed solution, place it in a 10 °C cold water bath and stir it ultrasonically for 1 h with an ultrasonic power of 100 W. Centrifuge for 10 min and select the supernatant to obtain a highly efficient scale inhibitor.

[0062] Example 3

[0063] The scale inhibitor contains the following components: 12 wt% trifluoroacetic acid, 4 wt% deoxycholic acid, 2 wt% methyl isothiocyanate, 3 wt% furfuryl thiocarbonate, 15 wt% hazelnut shell powder, 25 wt% ethanol, and the balance is water.

[0064] Weigh 125 g of ethanol and 195 g of water, mix them evenly, and then add 60 g of trifluoroacetic acid, 20 g of deoxycholic acid, 10 g of methyl isothiocyanate, and 15 g of furfuryl thiocarbonate in sequence, and mix them evenly. Select hazelnut shells, remove the surface impurities, place them in a constant-temperature drying oven and dry at 60 °C for 20 h to obtain a dry sample. Place the dried hazelnut shells in a grinder and crush and grind them into a powder with a mesh size of 200. Weigh 75 g of hazelnut shell powder and place it in the above-prepared mixed solution, place it in a water bath at 30 °C and stir ultrasonically for 45 min, and the ultrasonic power is 150 W. Centrifuge for 10 min and select the supernatant to obtain a high-efficiency scale inhibitor.

[0065] Comparative Example 1

[0066] Prepare the scale inhibitor according to Example 3, the difference is only that hazelnut shell powder is not added, and peanut shell powder is used instead.

[0067] Comparative Example 2

[0068] Prepare the scale inhibitor according to Example 3, the difference is only that deoxycholic acid is not added, and tetracosanoic acid is used instead.

[0069] Comparative Example 3

[0070] Prepare the scale inhibitor according to Example 3, the difference is only that hazelnut shell powder and deoxycholic acid are not added, and peanut shell powder and tetracosanoic acid are used instead.

[0071] Application Example 1

[0072] Take the scale inhibitors in the above Examples and Comparative Examples and place them in three identical reaction vessels, with 500 g of scale inhibitor in each vessel. Put the internal scale layer A (80% iron oxide, 11% silicate and silicon oxide, 5% calcium salt, 2% magnesium salt, 2% other impurities) of the equipment, 20# carbon steel coupons, and 316L stainless steel coupons into the three reaction vessels respectively, and soak them in a cold water bath (12 °C) for 3 h. After the soaking is completed, take the remaining scale layer, filter and weigh it, take the coupons, clean, dry, and weigh them, and calculate the scale removal rate, corrosion rate, and corrosion inhibition efficiency.

[0073]

[0074] Application Example 2

[0075] Take the scale inhibitors in the above Examples and Comparative Examples and place them in three identical reaction vessels, with 500 g of scale inhibitor in each vessel. Put the internal scale layer B (52% iron oxide, 21% silicate and silicon oxide, 10% calcium salt, 8% magnesium salt, 9% other impurities) of the equipment, 20# carbon steel coupons, and 316L stainless steel coupons into the three reaction vessels respectively, and soak them in a hot water bath (40 °C) for 3 h. After the soaking is completed, take the remaining scale layer, filter and weigh it, take the coupons, clean, dry, and weigh them, and calculate the scale removal rate, corrosion rate, and corrosion inhibition efficiency.

[0076]

[0077] Those skilled in the art can understand that, under the teaching of this specification, some modifications or adjustments can be made to the present invention. These modifications or adjustments should also fall within the scope defined by the claims of the present invention.

Claims

1. An efficient scale inhibitor, characterized in that, the scale inhibitor comprises the following components: 10wt%-15wt% trifluoroacetic acid, 2wt%-5wt% deoxycholic acid, 1wt%-3wt% isothiocyanate, 1.5wt%-3.5wt% furfuryl thiocarbonate, 14wt%-18wt% hazelnut shell powder, 20wt%-30wt% ethanol, and the balance is water.

2. The scale inhibitor according to claim 1, characterized in that, the isothiocyanate is one or more of methyl isothiocyanate, ethyl isothiocyanate, and allyl isothiocyanate.

3. A method for preparing a scale inhibitor, the scale inhibitor being the scale inhibitor according to claim 1 or 2, characterized in that, the method is: mixing ethanol and water, adding trifluoroacetic acid, deoxycholic acid, isothiocyanate and furfuryl thiocarbonate and mixing, adding hazelnut shell powder, ultrasonic treatment, centrifugation treatment, and the supernatant obtained is the target scale inhibitor.

4. The method according to claim 3, characterized in that, the hazelnut shell powder is surface-removed, dried at 40°C - 80°C for 10 - 24 h, and then ground into powder by a grinder; Preferably, the particle size of the hazelnut shell powder is 10 - 600 mesh.

5. The method according to claim 3 or 4, characterized in that, the ultrasonic treatment is to place it in a water bath at 10°C - 40°C and stir ultrasonically for 0.5 - 1 h, and the ultrasonic power is 100W - 200W.

6. A method for using a scale inhibitor, the scale inhibitor being the scale inhibitor according to claim 1 or 2, or the scale inhibitor prepared by the method according to any one of claims 3 - 5, characterized in that, in the method for use, the scale removal temperature is 10°C - 40°C and the scale removal time is 1 h - 3 h.

7. A use for preparing an efficient scale inhibitor, the scale inhibitor being the scale inhibitor according to claim 1 or 2, or the scale inhibitor prepared by the method according to any one of claims 3 - 5, characterized in that, the scale inhibitor is used for scale removal in the petrochemical field.

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