Scale cleaning agent composition for multipurpose industrial equipment

Abstract

The present invention relates to a multi-purpose scale cleaning agent composition for industrial facilities, and more specifically, to a scale cleaning agent composition comprising a scale decomposer, a scale dissolution promoter, a chelating agent, a scale formation inhibitor, and a corrosion inhibitor, which has excellent scale cleaning power along with improved effects of preventing scale reattachment and inhibiting corrosion.

Description

Technology Field

[0001] The present invention relates to a multi-purpose scale cleaning agent composition for industrial facilities, and more specifically, to a scale cleaning agent composition comprising a scale decomposer, a scale dissolution promoter, a chelating agent, a scale formation inhibitor, and a corrosion inhibitor, which has excellent scale cleaning power along with improved effects of preventing scale reattachment and inhibiting corrosion. Background Technology

[0002] Generally, during the operation of industrial facilities, inorganic salts such as calcium, magnesium, and iron are deposited on the internal surfaces of heat exchangers, boilers, cooling towers, and piping, forming scale. This scale reduces heat transfer efficiency and obstructs fluid flow, significantly lowering energy efficiency; in severe cases, it can cause equipment damage or shutdown. Therefore, regular scale removal is essential for the efficient operation of industrial facilities.

[0003] Conventional scale cleaners, primarily composed of strong acids, are effective for dissolving scale but have limitations, such as corrosion of the metal surface after cleaning and the rapid re-formation of scale. In particular, strong acid-based cleaners, such as hydrochloric acid or sulfuric acid, offer excellent immediate scale removal but are highly corrosive to metal materials, and residual scale remaining after cleaning acts as nucleation sites, promoting scale re-attachment.

[0004] Furthermore, existing cleaning agents focused solely on scale removal, neglecting to consider the prevention of scale re-formation or corrosion after cleaning. Consequently, issues regarding shortened cleaning cycles, reduced equipment lifespan due to repetitive cleaning, and increased maintenance costs have been continuously raised. In particular, when residual scale remains after cleaning, scale contained in the fluid is magnetically attracted to and adheres to the scale remaining on the inner walls of the equipment. This leads to a decline in efficiency and pronounced clogging after a short period of time.

[0005] Recently, with the increasing demand for the development of eco-friendly cleaning agents, research on cleaning agents utilizing chelating agents has been actively underway; however, there have been difficulties in developing optimal compositions that consider the interactions between various additives, including chelating agents. In particular, the lack of an integrated solution that simultaneously satisfies scale removal, prevention of reattachment, and corrosion prevention has limited effective and economical scale management. Prior art literature

[0006] Republic of Korea Registered Patent No. 10-2876158 (October 21, 2025) The problem to be solved

[0007] The objective of the present invention is to solve the problems of the prior art by providing a multi-purpose scale cleaning agent composition for industrial facilities that can simultaneously achieve excellent scale cleaning power along with effects of preventing scale reattachment and corrosion.

[0008] In addition, the objective of the present invention is to provide a scale cleaning agent composition that improves cleaning power by promoting the re-dissolution of scale attached to a metal surface through the synergistic action of a scale decomposer, a scale dissolution promoter, a chelating agent, and a scale formation inhibitor.

[0009] In addition, the objective of the present invention is to provide a scale cleaning agent composition that forms a stable composite protective film on a metal surface through a combination of phosphate and silicate as a scale formation inhibitor, thereby exhibiting a continuous prevention effect against scale reattachment over a long period of time. means of solving the problem

[0010] The present invention relates to a scale cleaning agent composition for multi-purpose industrial equipment, comprising 35 to 60 parts by weight of a scale decomposing agent, 1 to 20 parts by weight of a scale dissolution promoter, 0.1 to 3 parts by weight of a chelating agent, 0.5 to 5 parts by weight of a scale formation inhibitor, and 0.1 to 3 parts by weight of a corrosion inhibitor, wherein the composition promotes the re-dissolution of scale attached to a metal surface to improve scale cleaning power.

[0011] In a preferred embodiment of the present invention, the chelating agent may include one or more of ethylenediaminetetraacetic acid (EDTA), hydroxyethylethylenediaminetriacetic acid (HEDTA), diethylenetriaminepentaacetic acid (DTPA), triethylenetetraminehexaacetic acid (TTHA), nitrilotriacetic acid (NTA), iminodiaacetic acid (IDA), hydroxyethyliminodiaacetic acid (HEIDA), ethyleneglycoltetraacetic acid (EGTA), cyclohexanediaminetetraacetic acid (CDTA), glycine, N-methylglycine (Sarcosine), N,N-dimethylglycine, N,N-diaacetic acid, glycinediaacetic acid, methylglycinediaacetic acid (MGDA), dihydroxyethylglycine (DHEG), glutamic acid diacetic acid (GLDA), and aspartic acid diacetic acid (ASDA).

[0012] In a preferred embodiment of the present invention, the scale decomposing agent comprises one or more of phosphoric acid and citric acid, the scale dissolution promoter comprises one or more of butyl glycol and monoethylene glycol, the scale formation inhibitor comprises one or more of phosphate and silicate, and the corrosion inhibitor may comprise benzotriazole.

[0013] In a preferred embodiment of the present invention, the scale decomposing agent comprises 15 to 35 parts by weight of phosphoric acid and 20 to 25 parts by weight of citric acid, and the scale dissolution accelerator may comprise 1 to 5 parts by weight of butyl glycol and 1 to 5 parts by weight of monoethylene glycol.

[0014] In a preferred embodiment of the present invention, the scale formation inhibitor may contain phosphate and silicate in a weight ratio of 1 to 3:1 to 2, respectively.

[0015] In a preferred embodiment of the present invention, the composition can improve the durability of preventing scale re-attachment by forming a phosphate-silicate composite protective film on a metal surface and preventing scale particles from adhering to the metal surface through electrostatic repulsion.

[0016] In a preferred embodiment of the present invention, the composition may include the scale formation inhibitor and the corrosion inhibitor in a weight ratio of 1 to 5: 1 to 2, respectively. Effects of the invention

[0017] The multi-purpose industrial equipment scale cleaning agent composition according to the present invention can simultaneously achieve excellent scale cleaning power along with effects of preventing scale reattachment and corrosion through a combination of a scale decomposer, a scale dissolution promoter, a chelating agent, a scale formation inhibitor, and a corrosion inhibitor.

[0018] The multi-purpose industrial equipment scale cleaning agent composition according to the present invention can improve scale cleaning power by promoting the re-dissolution of scale attached to a metal surface through the synergistic action of a scale decomposer, a scale dissolution promoter, a chelating agent, and a scale formation inhibitor.

[0019] In addition, the composition of the present invention can form a phosphate-silicate composite protective film on a metal surface using a combination of phosphate and silicate, thereby exhibiting a continuous prevention effect against scale reattachment over a long period of time. Specific details for implementing the invention

[0020] The embodiments of the present invention are described below in detail so that those skilled in the art can easily implement the invention. The present invention may be embodied in various different forms and is not limited to the embodiments described herein.

[0021] The present invention will be described in detail below.

[0022] The present invention provides a scale cleaning agent composition.

[0023] The above scale cleaning agent composition is a multi-purpose industrial equipment scale cleaning agent composition comprising 35 to 60 parts by weight of a scale decomposing agent, 1 to 20 parts by weight of a scale dissolution promoter, 0.1 to 3 parts by weight of a chelating agent, 0.5 to 5 parts by weight of a scale formation inhibitor, and 0.1 to 3 parts by weight of a corrosion inhibitor, and the composition can improve scale cleaning power by promoting the re-dissolution of scale attached to a metal surface.

[0024] The aforementioned scale re-dissolution promoting effect is primarily caused by the role of the scale formation inhibitor. The scale formation inhibitor penetrates the interface between the metal surface and the scale layer, weakening the bonding force of the scale and destabilizing the scale structure, thereby allowing even firmly attached scale to be easily peeled off. At the same time, the chelating agent forms a stable complex with the metal ions constituting the scale, blocking the chemical bonding of the scale and preventing a decrease in scale cleaning power caused by the metal ions. Additionally, the scale dissolution promoter reduces the physical bonding force between the scale and the metal surface, facilitating the penetration of the scale decomposer, thereby exhibiting a synergistic effect. In particular, due to the combination of the scale formation inhibitor and the chelating agent, scale nucleation sites are removed, preventing remaining scale particles from acting as seeds for new scale formation. Furthermore, the scale dissolution promoter accelerates this process, which can significantly improve the overall scale cleaning power compared to the effect of each component individually.

[0025] The above scale decomposing agent may be included in the scale cleaning agent composition in an amount of 35 to 60 parts by weight. If the content of the scale decomposing agent is less than 35 parts by weight, it is difficult to secure sufficient scale dissolving power, and if it exceeds 60 parts by weight, metal corrosion may increase due to excessive acidity and economic efficiency may decrease.

[0026] The above scale decomposing agent may include one or more of phosphoric acid and citric acid, but preferably may include phosphoric acid and citric acid.

[0027] The above phosphoric acid plays a major role in directly dissolving calcium and magnesium scale due to its strong acidity, while citric acid assists in scale dissolution by blocking metal ions through chelating action, and simultaneously plays a role in adjusting the pH of the composition to an appropriate range.

[0028] The above scale decomposing agent may comprise 15 to 35 parts by weight of phosphoric acid, preferably 25 parts by weight of phosphoric acid, and 20 to 25 parts by weight of citric acid, preferably 23 parts by weight of citric acid. If the content of phosphoric acid is less than 15 parts by weight, the acidic scale dissolving power is insufficient, and the effect of removing calcium and magnesium scale is significantly reduced; if it exceeds 35 parts by weight, metal corrosion may be accelerated and work safety may be reduced due to excessive acidity. If the content of citric acid is less than 20 parts by weight, the chelating effect and pH buffering action are insufficient, and the synergistic effect with the scale decomposing agent is reduced; if it exceeds 25 parts by weight, workability may be reduced due to increased viscosity of the composition along with increased costs caused by an excessive amount of chelating agent.

[0029] The scale dissolution promoter may be included in the scale cleaning agent composition in an amount of 1 to 20 parts by weight. If the content of the scale dissolution promoter is less than 1 part by weight, the effect of improving penetration power is negligible, and if it exceeds 20 parts by weight, the effect may become saturated compared to the increase in cost, and economic efficiency may decrease.

[0030] The above scale dissolution promoter may include one or more of butyl glycol and monoethylene glycol, but preferably may include butyl glycol and monoethylene glycol.

[0031] The above butyl glycol and monoethylene glycol reduce the interfacial tension between the scale and the metal surface, thereby improving the penetration power of the scale decomposer and promoting the dispersion of dissolved scale components, which increases the overall cleaning efficiency.

[0032] The above scale dissolution promoter may comprise 1 to 5 parts by weight of butyl glycol, preferably 1 part by weight of butyl glycol, and 1 to 5 parts by weight of monoethylene glycol, preferably 1 part by weight of monoethylene glycol. If the content of the butyl glycol is less than 1 part by weight, the effect of reducing interfacial tension is negligible, resulting in insufficient improvement in the penetration power of the scale decomposer; if it exceeds 5 parts by weight, workability may be reduced due to increased viscosity of the composition along with increased costs resulting from excessive use. If the content of the monoethylene glycol is less than 1 part by weight, the effect of promoting the dispersion of dissolved scale components is insufficient, increasing the possibility of redeposition; if it exceeds 5 parts by weight, the stability of the composition may be reduced and economic efficiency may decrease due to the excessive dissolution promoter.

[0033] The above chelating agent may be included in the scale cleaning agent composition in an amount of 0.1 to 3 parts by weight, but preferably in an amount of 1.5 parts by weight. If the content of the chelating agent is less than 0.1 parts by weight, the metal ion blocking effect is insufficient, which may promote scale re-formation, and if it exceeds 3 parts by weight, increased costs and environmental burden may occur due to excessive use.

[0034] The above chelating agent may include one or more of ethylenediaminetetraacetic acid (EDTA), hydroxyethylethylenediaminetriacetic acid (HEDTA), diethylenetriaminepentaacetic acid (DTPA), triethylenetetraminehexaacetic acid (TTHA), nitrilotriacetic acid (NTA), iminodiaacetic acid (IDA), hydroxyethyliminodiaacetic acid (HEIDA), ethyleneglycoltetraacetic acid (EGTA), cyclohexanediaminetetraacetic acid (CDTA), glycine, N-methylglycine (Sarcosine), N,N-dimethylglycine, N,N-diaacetic acid glycine, glycinediaacetic acid, methylglycinediaacetic acid (MGDA), dihydroxyethylglycine (DHEG), glutamic acid diacetic acid (GLDA), and aspartate diacetic acid (ASDA).

[0035] The above chelating agent forms a stable chelate complex with metal ions such as calcium, magnesium, and iron to prevent scale re-formation, and acts synergistically with scale decomposers to enhance the scale dissolution effect.

[0036] The above scale formation inhibitor may be included in the scale cleaning agent composition in an amount of 0.5 to 5 parts by weight. If the content of the scale formation inhibitor is less than 0.5 parts by weight, the formation of a protective film is insufficient, and the effect of preventing scale reattachment is significantly reduced; if it exceeds 5 parts by weight, the cleaning effect may be reduced due to the formation of an excessive amount of precipitate.

[0037] The above scale formation inhibitor may include one or more of phosphate and silicate, but preferably may include phosphate and silicate.

[0038] The above phosphate may include one or more of sodium polyphosphate, sodium metaphosphate, sodium tripolyphosphate, and sodium orthophosphate, and the above silicate may include one or more of sodium silicate, potassium silicate, lithium silicate, sodium metasilicate, and sodium orthosilicate.

[0039] The above scale formation inhibitor may contain phosphate and silicate in a weight ratio of 1 to 3:1 to 2, respectively, but preferably in a weight ratio of 1.75:1.25.

[0040] The above scale formation inhibitor contains phosphate and silicate in a weight ratio of 1.75:1.25, respectively, thereby forming a uniform and stable phosphate-silicate composite protective film on the metal surface to prevent the adhesion of scale particles to the metal surface due to electrostatic interactions and to improve the long-term durability of preventing scale re-adhesion.

[0041] The above corrosion inhibitor may be included in the scale cleaning agent composition in an amount of 0.1 to 3 parts by weight, but preferably in an amount of 1.5 parts by weight. If the content of the corrosion inhibitor is less than 0.1 parts by weight, the corrosion prevention effect is significantly insufficient, and if it exceeds 3 parts by weight, problems such as precipitation due to solubility limits and increased costs may occur.

[0042] The above corrosion inhibitor may include benzotriazole.

[0043] The above benzotriazole can form a corrosion barrier by chemically adsorbing onto various metal surfaces, such as copper, stainless steel, and carbon steel.

[0044] In addition, the scale cleaning agent composition may include the scale formation inhibitor and the corrosion inhibitor in a weight ratio of 1 to 5:1 to 2, respectively, but preferably in a weight ratio of 3:1.5. If the weight ratio of the scale formation inhibitor and the corrosion inhibitor falls outside the range of 1 to 5:1 to 2, the individual effects of each component are exhibited, but the synergistic effect is significantly reduced, which may lead to a decrease in overall performance. However, by including the scale formation inhibitor and the corrosion inhibitor in a weight ratio of 3:1.5, a synergistic effect can be achieved that simultaneously prevents scale reattachment and corrosion caused by the ion exchange action of the scale formation inhibitor and the adsorption of the corrosion inhibitor.

[0045] Simple variations or modifications of the present invention can be easily implemented by those skilled in the art, and all such variations or modifications are considered to be included within the scope of the present invention.

[0047] Example 1: Preparation of a scale cleaning agent composition

[0048] 44 parts by weight of purified water were added as a solvent to a 500L stainless steel reactor, and 25 parts by weight of phosphoric acid (85%), a scale decomposing agent, were slowly added while stirring. Subsequently, 23 parts by weight of citric acid were added and completely dissolved, after which 1 part by weight of butyl glycol and 1 part by weight of monoethylene glycol, scale dissolution promoters, were sequentially added. Next, 1.5 parts by weight of EDTA (ethylenediaminetetraacetic acid), a chelating agent, were added and completely dissolved, and 3 parts by weight of a scale formation inhibitor containing trisodium phosphate and sodium silicate in a weight ratio of 1.75:1.25, respectively, were added. Finally, 1.5 parts by weight of benzotriazole, a corrosion inhibitor, were added and stirred for 30 minutes, after which the mixture was filtered to prepare a scale cleaning agent composition.

[0050] Example 2: Preparation of a scale cleaning agent composition (phosphate and silicate in a weight ratio of 1.75:1, respectively)

[0051] A scale cleaning agent composition was prepared in the same manner as in Example 1, except that it contained 3 parts by weight of a scale formation inhibitor containing trisodium phosphate and sodium silicate in a weight ratio of 1.75:1, respectively.

[0053] Example 3: Preparation of a scale cleaning agent composition (phosphate and silicate in a weight ratio of 1.75:2, respectively)

[0054] A scale cleaning agent composition was prepared in the same manner as in Example 1, except that it contained 3 parts by weight of a scale formation inhibitor containing trisodium phosphate and sodium silicate in a weight ratio of 1.75:2, respectively.

[0056] Example 4: Preparation of a scale cleaning agent composition (phosphate and silicate in a weight ratio of 1:1.25, respectively)

[0057] A scale cleaning agent composition was prepared in the same manner as in Example 1, except that it contained 3 parts by weight of a scale formation inhibitor containing trisodium phosphate and sodium silicate in a weight ratio of 1:1.25, respectively.

[0059] Example 5: Preparation of scale cleaning agent composition (phosphate and silicate in a weight ratio of 3:1.25, respectively)

[0060] A scale cleaning agent composition was prepared in the same manner as in Example 1, except that it contained 3 parts by weight of a scale formation inhibitor containing trisodium phosphate and sodium silicate in a weight ratio of 3:1.25, respectively.

[0062] Example 6: Preparation of a scale cleaning agent composition (scale formation inhibitor and corrosion inhibitor in a weight ratio of 3:0.1, respectively)

[0063] A scale cleaning agent composition was prepared in the same manner as in Example 1, except that it contained 3 parts by weight of a scale formation inhibitor containing trisodium phosphate and sodium silicate in a weight ratio of 1.75:1.25, respectively, and 0.1 parts by weight of benzotriazole.

[0065] Example 7: Preparation of a scale cleaning agent composition (scale formation inhibitor and corrosion inhibitor in a weight ratio of 3:3)

[0066] A scale cleaning agent composition was prepared in the same manner as in Example 1, except that it contained 3 parts by weight of a scale formation inhibitor containing trisodium phosphate and sodium silicate in a weight ratio of 1.75:1.25, respectively, and 3 parts by weight of benzotriazole.

[0068] Example 8: Preparation of a scale cleaning agent composition (scale formation inhibitor and corrosion inhibitor in a weight ratio of 0.5:1.5, respectively)

[0069] A scale cleaning agent composition was prepared in the same manner as in Example 1, except that it contained 0.5 parts by weight of a scale formation inhibitor containing trisodium phosphate and sodium silicate in a weight ratio of 1.75:1.25, respectively, and 1.5 parts by weight of benzotriazole.

[0071] Example 9: Preparation of a scale cleaning agent composition (scale formation inhibitor and corrosion inhibitor in a weight ratio of 5:1.5, respectively)

[0072] A scale cleaning agent composition was prepared in the same manner as in Example 1, except that it contained 5 parts by weight of a scale formation inhibitor containing trisodium phosphate and sodium silicate in a weight ratio of 1.75:1.25, respectively, and 1.5 parts by weight of benzotriazole.

[0074] Comparative Example 1: Preparation of a scale cleaning agent composition (phosphate and silicate in a weight ratio of 1.75 : 0.5, respectively)

[0075] A scale cleaning agent composition was prepared in the same manner as in Example 1, except that it contained 3 parts by weight of a scale formation inhibitor containing trisodium phosphate and sodium silicate in a weight ratio of 1.75:0.5, respectively.

[0077] Comparative Example 2: Preparation of a scale cleaning agent composition (phosphate and silicate in a weight ratio of 1.75 : 2.5, respectively)

[0078] A scale cleaning agent composition was prepared in the same manner as in Example 1, except that it contained 3 parts by weight of a scale formation inhibitor containing trisodium phosphate and sodium silicate in a weight ratio of 1.75:2.5, respectively.

[0080] Comparative Example 3: Preparation of a scale cleaning agent composition (phosphate and silicate in a weight ratio of 0.5:1.25, respectively)

[0081] A scale cleaning agent composition was prepared in the same manner as in Example 1, except that it contained 3 parts by weight of a scale formation inhibitor containing trisodium phosphate and sodium silicate in a weight ratio of 0.5:1.25, respectively.

[0083] Comparative Example 4: Preparation of a scale cleaning agent composition (phosphate and silicate in a weight ratio of 4:1.25, respectively)

[0084] A scale cleaning agent composition was prepared in the same manner as in Example 1, except that it contained 3 parts by weight of a scale formation inhibitor containing trisodium phosphate and sodium silicate in a weight ratio of 4:1.25, respectively.

[0086] Comparative Example 5: Preparation of a scale cleaning agent composition (scale formation inhibitor and corrosion inhibitor in a weight ratio of 3:0.05, respectively)

[0087] A scale cleaning agent composition was prepared in the same manner as in Example 1, except that it contained 3 parts by weight of a scale formation inhibitor containing trisodium phosphate and sodium silicate in a weight ratio of 1.75:1.25, respectively, and 0.05 parts by weight of benzotriazole.

[0089] Comparative Example 6: Preparation of a scale cleaning agent composition (scale formation inhibitor and corrosion inhibitor in a weight ratio of 3:3.5, respectively)

[0090] A scale cleaning agent composition was prepared in the same manner as in Example 1, except that it contained 3 parts by weight of a scale formation inhibitor containing trisodium phosphate and sodium silicate in a weight ratio of 1.75:1.25, respectively, and 3.5 parts by weight of benzotriazole.

[0092] Comparative Example 7: Preparation of a scale cleaning agent composition (scale formation inhibitor and corrosion inhibitor in a weight ratio of 0.1:1.5, respectively)

[0093] A scale cleaning agent composition was prepared in the same manner as in Example 1, except that it contained 0.1 parts by weight of a scale formation inhibitor containing trisodium phosphate and sodium silicate in a weight ratio of 1.75:1.25, respectively, and 1.5 parts by weight of benzotriazole.

[0095] Comparative Example 8: Preparation of a scale cleaning agent composition (scale formation inhibitor and corrosion inhibitor in a weight ratio of 6:1.5, respectively)

[0096] A scale cleaning agent composition was prepared in the same manner as in Example 1, except that it contained 6 parts by weight of a scale formation inhibitor containing trisodium phosphate and sodium silicate in a weight ratio of 1.75:1.25, respectively, and 1.5 parts by weight of benzotriazole.

[0098] Comparative Example 9: Preparation of a scale cleaning agent composition (without scale formation inhibitor)

[0099] A scale cleaning agent composition was prepared in the same manner as in Example 1, except that trisodium phosphate and sodium silicate were not added.

[0101] Comparative Example 10: Preparation of a scale cleaning agent composition (without corrosion inhibitor)

[0102] A scale cleaning agent composition was prepared in the same manner as in Example 1, except that benzotriazole was not added.

[0104] Comparative Example 11: Preparation of scale cleaning agent composition (10% aqueous hydrochloric acid solution)

[0105] A scale cleaning agent composition was prepared to become a 10% hydrochloric acid aqueous solution.

[0107] Experimental Example 1: Evaluation of Scale Cleaning Power of Scale Cleaning Agent Composition

[0108] To evaluate the scale cleaning power of the scale cleaning agent compositions prepared in each example and comparative example, stainless steel specimens (SUS 304, 50×50×2 mm) with artificially formed scale were prepared. First, the specimens were immersed in a hard water solution mixed with 1000 ppm CaCO3, 800 ppm CaSO4, and 500 ppm Mg(OH)2 to form scale at 80°C for 72 hours, and after measuring the initial weight of the formed scale, the specimens were immersed in a cleaning solution prepared by diluting the scale cleaning agent compositions of each example and comparative example with distilled water at a ratio of 1:10. After treatment at room temperature (25°C) for 4 hours, the specimens were removed, washed with distilled water, dried, and the weight of the remaining scale was measured. The scale removal rate was calculated according to the following formula and is shown in Table 1.

[0109] [Equation 1]

[0110] Scale Removal Rate (%) = (Initial Scale Weight - Remaining Scale Weight) / Initial Scale Weight × 100

[0112] division Composition ratio (scale formation inhibitor:corrosion inhibitor) Scale removal rate (%) Example 1 3:1.5 98.2 Example 8 0.5:1.5 94.3 Example 9 5:1.5 96.2 Comparative Example 7 0.1:1.5 68.3 Comparative Example 8 6:1.5 72.1 Comparative Example 9 -:1.5 62.5 Comparative Example 11 10% aqueous hydrochloric acid solution 95.7

[0114] Referring to Table 1, overall, all examples showed excellent scale removal rates of 94% or higher, whereas all comparative examples showed low performance of less than 73%. It was confirmed that Examples 1, 8, and 9, which contained scale formation inhibitors and corrosion inhibitors within the weight ratio range, had superior scale removal rates compared to comparative examples that contained scale formation inhibitors outside the weight ratio range or excluded scale formation inhibitors. In particular, Example 1 achieved the highest scale removal rate of 98.2%, which is due to the effect of improved cleaning power caused by the scale formation inhibitor promoting the re-dissolution of scale attached to the metal surface. The 10% hydrochloric acid aqueous solution of Comparative Example 11 showed a removal rate of 95.7%, but exhibited lower performance compared to Example 1, confirming that Example 1, with a weight ratio of scale formation inhibitor to corrosion inhibitor of 3:1.5, had the best scale cleaning power.

[0116] Experimental Example 2: Evaluation of the Durability of Scale Reattachment Prevention of a Scale Cleaner Composition

[0117] To evaluate the sustained ability of the scale cleaning agent compositions prepared in each example and comparative example to prevent scale reattachment, specimens cleaned using the scale cleaning agent compositions of each example and comparative example as in Experimental Example 1 were immersed again in a 1000 ppm CaCO3 solution to observe the degree of scale reattachment. The amount of scale re-formation was measured at 7, 14, and 30 days after cleaning treatment, respectively, and the scale reattachment inhibition rate was calculated according to the following formula in comparison with an untreated control group and is shown in Table 2.

[0118] [Equation 2]

[0119] Scale reattachment inhibition rate (%) = (Scale formation in control group - Scale formation in treatment group) / Scale formation in control group × 100

[0121] division Composition ratio (phosphate:silicate) Inhibition rate (%) after 7 days Inhibition rate (%) after 14 days Inhibition rate (%) after 30 days Example 1 1.75:1.25 92.8 88.6 85.2 Example 2 1.75:1 91.3 87.1 83.7 Example 3 1.75:2 90.6 86.8 82.9 Example 4 1:1.25 89.7 85.4 81.8 Example 5 3:1.25 88.9 84.7 80.6 Comparative Example 1 1.75:0.5 78.4 65.2 52.3 Comparative Example 2 1.75:2.5 76.8 63.7 48.9 Comparative Example 3 0.5:1.25 72.1 58.6 41.2 Comparative Example 4 4:1.25 74.5 61.3 45.8 Comparative Example 11 10% aqueous hydrochloric acid solution 35.2 18.7 8.3

[0123] Referring to Table 2, overall, the Examples maintained an excellent long-term scale reattachment inhibition rate of over 80% even after 30 days, whereas the Comparative Examples all showed a low persistence of less than 53%. It was confirmed that Examples 1 to 5, containing phosphate and silicate within the weight ratio range, demonstrated superior scale reattachment prevention persistence over time compared to the Comparative Examples containing phosphate and silicate outside the weight ratio range. In particular, Example 1 exhibited the best persistence, showing a minimized decrease in inhibition rate over time with 92.8% after 7 days, 88.6% after 14 days, and 85.2% after 30 days. This is attributed to the effect of effectively preventing scale reattachment over a long period, as a uniform and stable phosphate-silicate composite protective film is continuously maintained on the metal surface by the 1.75:1.25 weight ratio combination of phosphate and silicate. In contrast, the 10% hydrochloric acid aqueous solution of Comparative Example 11 showed 35.2% after 7 days, and after 30 days It was confirmed that the scale reattachment prevention durability of Example 1, in which the weight ratio of phosphate and silicate was 1.75:1.25 respectively, was the best, as it decreased sharply to 8.3% and showed no durability at all.

[0125] Experimental Example 3: Evaluation of Scale Reattachment Prevention and Corrosion Prevention of Scale Cleaning Agent Composition

[0126] In order to simultaneously evaluate the scale reattachment prevention and corrosion prevention capabilities of the scale cleaning agent compositions prepared in each example and comparative example, specimens cleaned using the scale cleaning agent compositions of each example and comparative example as in Experimental Example 1 were immersed in a 1000 ppm CaCO3 solution and left at 60°C for 7 days, after which the amount of scale re-formation was measured, and the scale reattachment inhibition rate was calculated by comparing it with an untreated control group. In addition, stainless steel (SUS 304), carbon steel (SS400), and copper (Cu) specimens were prepared, and each specimen was immersed in a cleaning solution according to the scale cleaning agent compositions of each example and comparative example for 24 hours, after which the weight loss was measured to calculate the corrosion rate. The corrosion current density was measured using the polarization resistance measurement method, and the final corrosion inhibition rate was calculated according to the following formula by comparing it with an untreated control group and is shown in Table 3.

[0127] [Equation 3]

[0128] Corrosion inhibition rate (%) = (Control group corrosion rate - Treatment group corrosion rate) / Control group corrosion rate × 100

[0130] division Composition ratio (scale formation inhibitor:corrosion inhibitor) Scale reattachment inhibition rate (%) Stainless Steel SUS304 Corrosion Inhibition Rate (%) Carbon Steel SS400 Corrosion Inhibition Rate (%) Copper (Cu) Corrosion Inhibition Rate (%) Example 1 3:1.5 92.8 96.8 94.2 95.6 Example 6 3:0.1 85.4 87.2 83.6 85.9 Example 7 3:3 91.6 95.1 92.3 94.2 Example 8 0.5:1.5 86.7 89.6 86.4 88.1 Example 9 5:1.5 89.2 91.8 88.7 90.3 Comparative Example 5 3:0.05 58.3 64.7 58.2 61.8 Comparative Example 6 3:3.5 75.8 82.1 79.3 80.7 Comparative Example 7 0.1:1.5 62.9 71.2 67.8 69.4 Comparative Example 8 6:1.5 69.4 76.8 72.4 74.9 Comparative Example 9 -:1.5 48.6 58.9 53.1 56.2 Comparative Example 10 3:- 38.2 44.6 38.7 42.3 Comparative Example 11 10% aqueous hydrochloric acid solution 15.7 12.4 8.9 15.7

[0132] Referring to Table 3, overall, the examples demonstrated excellent scale reattachment and corrosion prevention capabilities for all metal materials, with a scale reattachment inhibition rate of 85% or higher and a corrosion inhibition rate of 85% or higher, whereas the comparative examples all exhibited low performance with a scale reattachment inhibition rate of less than 76% and a corrosion inhibition rate of less than 83%. It was confirmed that Examples 1 and 6 to 9, which contained scale formation inhibitors and corrosion inhibitors within the weight ratio range, demonstrated superior scale reattachment and corrosion prevention capabilities compared to the comparative examples that contained or excluded scale formation inhibitors or corrosion inhibitors outside the weight ratio range. In particular, Example 1 exhibited the best scale reattachment and corrosion prevention capabilities with a scale reattachment inhibition rate of 92.8%, a stainless steel corrosion inhibition rate of 96.8%, a carbon steel corrosion inhibition rate of 94.2%, and a copper corrosion inhibition rate of 95.6%. This is attributed to the 3:1.5 weight ratio combination of the scale formation inhibitor and the corrosion inhibitor, specifically the ion exchange action of the scale formation inhibitor and the corrosion inhibitor benzotriazole. This is due to the synergistic effect of preventing scale reattachment and corrosion by simultaneously forming an adsorption film on the metal surface. The 10% hydrochloric acid aqueous solution of Comparative Example 11 showed very low prevention effects, with a scale reattachment inhibition rate of 15.7%, a stainless steel corrosion inhibition rate of 12.4%, a carbon steel corrosion inhibition rate of 8.9%, and a copper corrosion inhibition rate of 15.7%, indicating strong corrosion and a lack of scale reattachment prevention ability. Therefore, it was confirmed that the scale reattachment and corrosion prevention ability of Example 1, in which the weight ratio of the scale formation inhibitor and the corrosion inhibitor was 3:1.5, was the most superior.

[0133] Simple variations or modifications of the present invention can be easily implemented by those skilled in the art, and all such variations or modifications are considered to be included within the scope of the present invention.

Claims

Claim 1 A composition for a multi-purpose scale cleaning agent for industrial equipment comprises 35 to 60 parts by weight of a scale decomposing agent, 1 to 20 parts by weight of a scale dissolution accelerator, 0.1 to 3 parts by weight of a chelating agent, 0.5 to 5 parts by weight of a scale formation inhibitor, and 0.1 to 3 parts by weight of a corrosion inhibitor; the composition promotes the re-dissolution of scale attached to a metal surface to improve scale cleaning power; the scale decomposing agent comprises one or more of phosphoric acid and citric acid; the scale dissolution accelerator comprises one or more of butyl glycol and monoethylene glycol; the scale formation inhibitor comprises one or more of phosphate and silicate; the corrosion inhibitor comprises benzotriazole; and the scale decomposing agent comprises 15 to 35 parts by weight of phosphoric acid and 20 to A scale cleaning agent composition characterized by comprising 25 parts by weight, wherein the scale dissolution promoter comprises 1 to 5 parts by weight of butyl glycol and 1 to 5 parts by weight of monoethylene glycol. Claim 2 A scale cleaning agent composition according to claim 1, wherein the chelating agent comprises one or more of ethylenediaminetetraacetic acid (EDTA), hydroxyethylethylenediaminetriacetic acid (HEDTA), diethylenetriaminepentaacetic acid (DTPA), triethylenetetraminehexaacetic acid (TTHA), nitrilotriacetic acid (NTA), iminodiaacetic acid (IDA), hydroxyethyliminodiaacetic acid (HEIDA), ethyleneglycoltetraacetic acid (EGTA), cyclohexanediaminetetraacetic acid (CDTA), glycine, N-methylglycine (Sarcosine), N,N-dimethylglycine, N,N-diaacetic acid, glycinediaacetic acid, methylglycinediaacetic acid (MGDA), dihydroxyethylglycine (DHEG), glutamic acid diacetic acid (GLDA), and aspartic acid diacetic acid (ASDA). Claim 3 delete Claim 4 delete Claim 5 A scale cleaning agent composition according to claim 1, characterized in that the scale formation inhibitor comprises phosphate and silicate in a weight ratio of 1 to 3:1 to 2, respectively. Claim 6 A scale cleaning agent composition according to claim 5, characterized in that the composition improves the durability of preventing scale re-attachment by forming a phosphate-silicate composite protective film on a metal surface to prevent scale particles from adhering to the metal surface through electrostatic repulsion. Claim 7 A scale cleaning agent composition according to claim 1, characterized in that the composition comprises the scale formation inhibitor and the corrosion inhibitor in a weight ratio of 1 to 5:1 to 2, respectively.

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