TW202223159A - Organic anticorrosive compositions for closed cooling water system and method of using same - Google Patents

Abstract

The present invention relates to organic anticorrosive compositions for a closed cooling water system and a method of using the same. The organic anticorrosive compositions include demineralized water, an alkali metal hydroxide and an organic amine compound. By the organic amine compound with a specific chemical structure, the organic anticorrosive compositions for the closed cooling water system can decrease corrosive ratios for carbon steel and copper and extend treating time of the organic anticorrosive compositions in the closed cooling water system.

Description

Organic type corrosion inhibitor composition for closed cooling water system and method of use thereof

The present invention relates to an organic type anti-corrosion composition for use in a closed cooling water system and a method of using the same, and in particular to an organic type anti-corrosion composition that can reduce the corrosion rate and increase the processing time of the closed cooling water system and how to use it.

The cooling water system is mainly used to cool important production equipment so that it can operate normally. This cooling water system is divided into two types: one is an open cooling water system, and the other is a closed cooling water system. As far as steel plants are concerned, since blast furnaces are the production core of steel plants, they are usually equipped with closed cooling water systems. This closed cooling water system is mainly used to cool important equipment such as the cooling box (Cooling Box), furnace body ring pipe (Main Ring) and blower nozzle (Tuyere) of the blast furnace.

In a closed cooling water system, demineralized water is generally used as cooling water. Due to the large amount of circulating water, the water quality requirements for cooling water are quite high, and anti-corrosion agents need to be added to reduce the occurrence of corrosion. The requirement of cooling water for the carbon steel corrosion rate of the aforementioned important equipment is not more than 1.0 mil per year ( mpy), and the copper corrosion rate requirement is not greater than 0.5 mils per year (mpy). If the corrosion rate cannot meet the above requirements, it will seriously corrode important equipment, resulting in sediment blockage and even perforation, which will affect the smoothness of production.

After the main line of the closed cooling water system has been subjected to operations such as fouling, pickling and rust removal, cleaning and film forming, if the treatment of the cooling water is not well controlled, once the copper concentration of the demineralized water unexpectedly rises to 0.8 When the concentration of iron is greater than 1.0 mg/L, the closed cooling water system will start to generate galvanic corrosion. Therefore, to avoid significant losses, cooling water must be treated with purification strategies to improve water quality. Further, increase the concentration of the corrosion inhibitor to restore to meet the requirements of the closed cooling water system for the corrosion rate.

For example, a purification strategy can perform extensive drainage and replenishment. However, this strategy will waste a lot of water resources and require additional supplementation of corrosion inhibitor, so it is not cost-effective.

Other treatment methods use ion exchange resin method (Ion Exchange Method), ultrafiltration/reverse osmosis method (Ultra Filteration/Reverse Osmosis Method) or reverse electrode electrodialysis method (Electrodialysis Reversal Method) to reduce iron and/or copper in water. Concentration of ingredients, but these methods of processing equipment are expensive or require additional operating manpower.

In addition, the closed cooling water system belongs to the alkaline water treatment scheme, that is, the pH value of the water body is not less than 9. To protect the environment, carbon steel corrosion inhibitors were changed from chromates to molybdates (eg Na ₂ MoO ₄ ) and nitrites (eg NaNO ₂ ). In this inorganic type corrosion inhibitor, the concentration of anionic molybdate is required to be greater than 185 mg/mL, and the concentration of anionic nitrite is required to be greater than 200 mg/mL. However, this inorganic type corrosion inhibitor easily affects the stability of cooling water, so the applicability is greatly reduced.

When the concentration of carbon steel anticorrosion composition (molybdate and nitrite) and copper anticorrosion composition (methylbenzotriazole, Tolyltriazole, TTA) is low, the transmission line, cooling box, furnace body ring Carbon steel/copper materials in equipment such as pipes and blower nozzles are gradually corroded, and deposition corrosion occurs in the low flow area of the closed cooling water system, so that the pressure gauge detection point is blocked by deposits. Ultimately, the treatment equipment must be shut down for repairs and increases the cost of water and corrosion inhibitors.

^In addition, when the airtightness of the closed cooling water system is not good, the outside air will enter the closed cooling water system, which will lead to a large number of microorganisms. Nitrate will be used by microorganisms and oxidized to nitrate, which will lose its anti-corrosion effect and increase the corrosion rate of carbon steel. Furthermore, nitrite is a carcinogen and is easily used by microorganisms, which leads to the optimization of water bodies, so it should be avoided.

At the same time, since the TTA of the copper corrosion inhibitor composition is also decomposed by microorganisms, the corrosion rate of copper will increase. In addition, molybdenum in molybdate is a precious metal, which increases the cost of the corrosion inhibitor composition. Secondly, since high concentrations of molybdenum ions are biologically toxic, the concentration of molybdenum ions in the discharge water must comply with regulations.

In view of this, there is an urgent need to develop an organic-type anticorrosion composition for closed cooling water system, so as to improve the above-mentioned shortcomings of the conventional anticorrosion composition for closed cooling water system.

In view of the above problems, one aspect of the present invention is to provide an organic type corrosion inhibitor composition for a closed cooling water system. By using organic amine compounds with specific chemical structure, the organic anti-corrosion composition can reduce the corrosion rate of carbon steel and copper, and increase the processing time of the organic anti-corrosion composition in the closed cooling water system.

Another aspect of the present invention provides a method of using an organic type corrosion inhibitor composition. This method of use uses the aforementioned organic anti-corrosion composition, so it can reduce the corrosion rate of carbon steel and copper, and increase the processing time of the organic anti-corrosion composition in the closed cooling water system.

According to an aspect of the present invention, an organic type corrosion inhibitor composition for a closed cooling water system is provided. The organic anti-corrosion composition for closed cooling water system includes demineralized water, alkali metal hydroxide and organic amine compounds. The organic amine compound has an aromatic ring structure containing 1 to 3 nitrogen atoms, and the molecular weight of the organic amine compound is 60 g/mole to 280 g/mole. Based on the weight of the organic type corrosion inhibitor composition, 100% by weight, the content of demineralizing water is 50% by weight to 80% by weight, the content of alkali metal hydroxide is 10% by weight to 25% by weight, and the content of organic amine compound From 10 weight percent to 25 weight percent.

According to an embodiment of the present invention, the cracking temperature of the organic amine compound is equal to or greater than 100°C.

According to another aspect of the present invention, a method of using an organic type corrosion inhibitor composition is provided. The method of use includes adding the aforementioned organic anti-corrosion composition for closed cooling water system to the water body of the closed cooling water system. Based on the volume of the water body of the closed cooling water system is one liter, the usage amount of the organic amine compound is 1000mg to 2000mg.

According to an embodiment of the present invention, the pH value of the water body is 8.5 to 10.5.

According to another embodiment of the present invention, the temperature of the water body is 50°C to 60°C.

According to another embodiment of the present invention, the treatment time of the organic-type corrosion inhibitor composition in the closed cooling water system is equal to or greater than 30 days.

According to another embodiment of the present invention, the water body has a corrosion rate of carbon steel not greater than 1.0 mpy and/or a corrosion rate of copper not greater than 0.5 mpy.

To sum up, the organic anti-corrosion composition for closed cooling water system using the present invention comprises demineralized water, alkali metal hydroxide and organic amine compounds. The organic amine compound has a specific chemical structure, and the chemical structure has an aromatic ring structure containing 1 to 3 nitrogen atoms. The nitrogen atom(s) can be bonded with the metal atoms in the carbon steel and copper materials, so as to be adsorbed on the surfaces of the carbon steel and copper materials, thereby forming a stable and dense protective layer. Accordingly, the organic-type anti-corrosion composition for closed cooling water system and the method for using the same of the present invention can reduce the corrosion rate of carbon steel and copper, and increase the processing time of the organic-type anti-corrosion composition in the closed cooling water system .

The manufacture and use of embodiments of the present invention are discussed in detail below. It should be appreciated, however, that the embodiments provide many applicable inventive concepts that can be embodied in a wide variety of specific contexts. The specific embodiments discussed are provided for illustration only, and are not intended to limit the scope of the invention.

The treatment time of the present invention is to use the corrosion inhibitor composition in the water body of a water system, after a period of use, measure the corrosion rate of the standard carbon steel material (or standard copper material) after contacting the aforementioned water body, and according to The corrosion rate is used to judge the treatment time of the corrosion inhibitor composition in this water system. The qualified standard of the corrosion rate of the standard carbon steel material is not more than 1.0mpy, and the qualified standard of the corrosion rate of the standard copper material is not more than 0.5mpy. In the case that the corrosion rate of standard carbon steel material (or standard copper material) meets the qualified standard, the longest service time is defined as the processing time of the organic type corrosion inhibitor composition in the closed cooling water system.

The organic type corrosion inhibitor composition for closed cooling water system of the present invention comprises demineralized water, alkali metal hydroxide and organic amine compounds. The demineralized water of the present invention refers to the water body after the general tap water has been sequentially treated by sand filtration, activated carbon, cation exchange resin, anion exchange resin and mixed bed resin, that is, it does not contain ions that are corrosive to iron and copper metals and De-hardened water to avoid corrosion of iron and/or copper metals and scaling in closed cooling water systems. In some embodiments, such ions include, but are not limited to, chloride ions and bromide ions, and the hardness removal treatment is a method of removing calcium ions, magnesium ions, iron ions, and/or manganese ions, among others. The pH of the demineralized water may be 5.5 to 6.5, preferably 6.0, after the hardness removal treatment. In addition, the specific corrosive ion and hardness removal treatments may be known to those of ordinary skill in the art to which the present invention pertains.

The aforementioned demineralized water is a solvent, and is used to dissolve alkali metal hydroxides and organic amine compounds. In some embodiments, the alkali metal hydroxide and the organic amine compound are sequentially dissolved in the demineralized water. Since the organic amine compound is easily dissolved in the alkaline solution containing the alkali metal hydroxide, the solution preparation of the organic type anti-corrosion agent composition can be completed quickly. In other embodiments, the alkali metal hydroxide and the organic amine compound are added to the demineralized water at the same time, and then stirred until the two are completely dissolved.

The content of demineralized water is 50 to 80 percent by weight based on 100 percent by weight of the organic-type anti-corrosion composition used in the closed cooling water system. When the content of demineralization water is less than 50% by weight, alkali metal hydroxides and/or organic amine compounds are not completely dissolved by demineralization water, but form a heterogeneous solution, which cannot be used in closed cooling water systems. When the content of demineralized water is more than 80 weight percent, the concentration of alkali metal hydroxide is too low, and it is difficult to completely dissolve the organic amine compound. Therefore, when the content of demineralized water is not from 50 wt% to 80 wt%, the corrosion rate of cooling water to carbon steel and copper will increase, and the anti-corrosion effect of organic anti-corrosion composition in closed cooling water system will be greatly reduced .

The alkali metal hydroxide may include, but is not limited to, lithium hydroxide, potassium hydroxide, sodium hydroxide, or any combination of the foregoing. The content of the alkali metal hydroxide is 10 to 25 wt %, preferably 15 to 20 wt %, based on 100 wt % of the organic type anti-corrosion composition. When the content of alkali metal hydroxide is less than 10% by weight, the dissolution of organic amine compounds is not good, which reduces the anti-corrosion effect of cooling water on carbon steel and copper, and shortens the use of organic anti-corrosion composition in a closed cooling water system. processing time. When the content of alkali metal hydroxide is greater than 25% by weight, the pH value of the water body of the closed cooling water system is too high, and the corrosion rate of the water body to carbon steel and copper is increased.

The organic amine compound of the present invention has an aromatic cyclic structure containing 1 to 3 nitrogen atoms. In detail, the lone pair electrons of the nitrogen atom(s) are easy to coordinately bond with the empty orbital domains of metal atoms in carbon steel and copper materials, and the unlocalized resonance electron cloud in the aromatic ring structure can also be enhanced. The bonding force between nitrogen atoms and metal atoms improves the adsorption of organic amine compounds and metal surfaces. The main electronic chemical bonding mechanism is that the aromatic ring structure can provide the π-π interaction force between the molecules, so that the molecules of the organic amine compounds are tightly stacked, thereby forming a stable and dense protective layer on the metal surface.

When the chemical structure of the organic amine compound contains an aromatic ring structure with less than one nitrogen atom, the organic amine compound is not easily adsorbed on the surface of carbon steel and copper materials, thereby increasing the water body of the closed cooling water system. Corrosion rate of copper, and shorten the processing time of organic anti-corrosion composition in closed cooling water system. When the chemical structure of the organic amine compound has an aromatic cyclic structure containing more than 3 nitrogen atoms, the electron attraction between the organic amine compound and the metal surface is weak, resulting in poor corrosion resistance.

In some embodiments, the chemical structure of the organic amine compound selectively includes a hydrophobic group, and the intermolecular stacking is formed by the Van der Waals force generated by the hydrophobic groups in adjacent molecules to form a hydrophobic stacking Floor. The hydrophobic stack repels water molecules, thereby reducing the corrosion rate of carbon steel and copper in closed cooling water systems.

(I)

(II)

(III)

(IV)

(V)。 In some embodiments, the organic amine compounds may include, but are not limited to, amine compounds of the structures shown in the following formulae (I) to (V):

(I)

(II)

(III)

(IV)

(V).

In the above formulae (I) to (V), R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, a hydroxyl group, a methoxy group, an ethoxy group, an aldehyde group having 1 to 2 carbon atoms or a primary amine group . Preferably, R represents tert-butyl, methoxy or primary amine. The aforementioned R group with electron-pushing properties can help the nitrogen atom on the aromatic ring to bond with the metal atom in carbon steel and copper materials, thereby reducing the corrosion rate of carbon steel and copper materials, and helping to stabilize organic amines The adsorption of compounds on the surface of carbon steel and copper materials can reduce the loss of organic amine compounds in the closed cooling water system, thereby increasing the processing time of the organic anti-corrosion composition in the closed cooling water system. In other embodiments, R represents a hydrophobic group that is an electron-pushing group (eg, tert-butyl). As mentioned above, the hydrophobic group can also help the organic amine compound to form a hydrophobic stacked layer, thereby reducing the corrosion rate.

As mentioned above, the molecular weight of the organic amine compound of the present invention is 60 g/mole to 280 g/mole, and preferably 122 g/mole to 155 g/mole. When the molecular weight of the organic amine compound is less than 60 g/mole, the organic amine compound cannot have an aromatic cyclic structure containing 1 to 3 nitrogen atoms, so it cannot be stably adsorbed on the surface of carbon steel and/or copper, thereby increasing the Corrosion rate of carbon steel and copper, and shorten the processing time of organic anti-corrosion composition in closed cooling water system. When the molecular weight of the organic amine compound is greater than 280g/mole, the water solubility of the organic amine compound becomes poor, and it cannot exist stably in the water body, so the corrosion rate of carbon steel and copper is increased, and the organic corrosion inhibitor composition is shortened. The processing time of the cooling water system.

The content of the organic amine compound is 10 to 25 wt %, preferably 15 to 20 wt %, based on 100 wt % of the organic type anti-corrosion composition for closed cooling water system. When the content of the organic amine compound is less than 10% by weight, too little organic amine compound cannot completely cover the surface of carbon steel and/or copper, which increases the corrosion rate of carbon steel and copper, and shortens the time period of the organic anti-corrosion composition in airtight cooling. Treatment time of the water system. When the content of the organic amine compound is more than 25 weight percent, the organic amine compound is easily crystallized from the cooling water, and the cost of the organic type corrosion inhibitor composition is increased.

In some embodiments, the organic amine compound has a cracking temperature equal to or greater than 100°C. The temperature of the water body of the closed cooling water system is maintained at 50°C to 60°C to achieve the purpose of cooling the important equipment of the blast furnace. Therefore, organic amine compounds can stably exist in water to exert the anticorrosion effect on carbon steel and copper. In some embodiments, the cracking temperature of the organic amine compound is preferably 100°C to 120°C. For example, the pyrolysis temperature of benzotriazole is 100°C.

In some embodiments, the organic type corrosion inhibitor composition for closed cooling water system of the present invention does not contain molybdate, nitrite and methyl benzotriazole, so it has the advantages of low price and good environment.

The use method of the organic-type anti-corrosion composition of the present invention comprises adding the aforementioned organic-type anti-corrosion composition to the water body of the closed cooling water system. The addition amount of the organic type corrosion inhibitor composition is determined according to the usage amount of the organic amine compound in the water body of the closed cooling water system. The usage amount of the organic amine compound refers to the weight of the organic amine compound contained in the water body based on the volume of the water body of the closed cooling water system as one liter, and the weight unit is expressed in mg.

In some embodiments, based on the volume of the water body of the closed cooling water system being one liter, the usage amount of the organic amine compound is 1000 mg to 2000 mg, and preferably 1200 mg to 1600 mg. In a specific example, an organic anti-corrosion composition containing a high concentration of organic amine compounds is first prepared, and then the aforementioned organic anti-corrosion composition is added to the water body of the closed cooling water system, so that the organic amine compounds The content in the water body conforms to the above-mentioned usage amount, and the addition ratio can be calculated by volume ratio or weight ratio.

Generally speaking, the pH value of the water body of the closed cooling water system is maintained at an alkaline level to avoid corrosion of carbon steel. Further, a corrosion inhibitor composition is added to the water body to reduce the corrosion of carbon steel and copper. In some embodiments, the pH of the water in the closed cooling water system is 8.5 to 10.5. When the pH value of the water body of the closed cooling water system is within the aforementioned range, the organic anti-corrosion composition can form a stable and dense protective layer on the surface of carbon steel and copper, so as to reduce the corrosion rate of carbon steel and copper, and increase the corrosion rate of carbon steel and copper. Treatment time of organic type anti-corrosion composition in closed cooling water system. The aforementioned alkaline environment can enhance the surface adsorption capacity of the amine group of the organic amine compound to carbon steel and copper.

In some embodiments, the closed cooling water system includes a circulation line, wherein the circulation line is provided with a water body inlet, a water body outlet, and a pump. The pump is used to make the water flow in a predetermined direction and circulate in the closed cooling water system. In addition, the circulation pipeline is equipped with a device for measuring the corrosion rate to measure the corrosion rate of standard carbon steel materials and standard copper materials, so as to evaluate the corrosion protection effect of the organic corrosion inhibitor composition. In a specific example, the water inflow of the equipment for measuring the corrosion rate is 48 tons/day, and the flow rate is 2m/s.

Further, the circulation pipeline is provided with a liquid medicine tank, and the liquid medicine tank contains the organic type anti-corrosion agent composition and is used for adding the organic type anti-corrosion agent composition to the water body in the closed cooling water system.

In other embodiments, the circulation pipeline selectively includes a filter to filter the suspended matter in the water body, so as to prevent the suspended matter from being blocked in the pipeline. Therefore, as the filtration time increases, the traditional corrosion inhibitor will be filtered out by the filter and gradually worn out. However, the organic amine compound of the organic anti-corrosion composition of the present invention can form a stable adsorption layer on the surface of carbon steel and copper materials, and will not flow through the filter with water, thereby reducing the occurrence of wear and tear.

As mentioned above, the treatment time of the corrosion inhibitor composition in the water body of the water system is determined according to the corrosion rate. In some embodiments, according to the test results of the corrosion rates of standard carbon steel materials and standard copper materials, the treatment time of the organic-type corrosion inhibitor composition of the present invention in a closed cooling water system may be equal to or greater than 30 days.

In some embodiments, the water body of the closed cooling water system has a carbon steel corrosion rate of not greater than 1.0 mpy and/or a copper corrosion rate of not greater than 0.5 mpy, and preferably has a carbon steel corrosion rate of less than 0.1 mpy and/or Copper corrosion rate less than 0.05mpy. As mentioned above, since the organic amine compounds in the organic anti-corrosion composition can be stably adsorbed on the surface of carbon steel and copper materials and form a stable adsorption layer, the loss of organic amine compounds in flowing water is very high. Low. Therefore, the processing time of the organic type corrosion inhibitor composition in the closed cooling water system is increased, and the corrosion rate of carbon steel and copper is reduced.

The following examples are used to illustrate the application of the present invention, but it is not intended to limit the present invention. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention.

Preparation of anti-corrosion composition

Example 1

Dissolve 20 g of sodium hydroxide in 65 g of demineralized water to form a sodium hydroxide solution. Then, 15 g of benzotriazole (Benzotriazole) was added to the aforementioned sodium hydroxide solution, and stirred and mixed to completely dissolve the benzotriazole, thereby preparing the corrosion inhibitor composition of Example 1.

Comparative Example 1

273 mg of sodium molybdate, 261 mg of sodium nitrite, and 1.5 mg of methylbenzotriazole were added to 1 liter of demineralized water, and stirred and mixed to completely dissolve the aforementioned three components, thereby preparing the comparative example 1. Corrosion inhibitor composition.

Application of anti-corrosion composition in closed cooling water system

Application example 1

Application Example 1 is to use the corrosion inhibitor composition of Example 1 in a laboratory cup and bottle system, and use demineralized water as the water body, wherein the volume of the water body is one liter, and the amount of benzotriazole used is 1000 mg , and the use time is 1 month to measure the corrosion rate of standard carbon steel materials.

Application Examples 2 to 3 and Comparative Application Examples 1 to 2

In the application examples 2 to 3 and the comparative application examples 1 to 2, the corrosion rate was measured by the same method as that of the application example 1. The difference is that the usage amount and usage time of the anti-corrosion benzotriazole in application examples 2 to 3 are different from those in application example 1, and comparative application example 1 only uses demineralized water (does not include corrosion inhibitor composition, and the pH value is 6). In addition, Comparative Application Example 2 only uses sodium hydroxide solution (prepared with demineralized water and sodium hydroxide, and has a pH value of 9), wherein the sodium hydroxide solution is the sodium hydroxide solution in the aforementioned Example 1. Table 1 shows the conditions and results of Application Examples 1 to 3 and Comparative Application Examples 1 to 2.

Application example 4

Application Example 4 is to use the corrosion inhibitor composition of Example 1 in the mold field equipment system. The water treatment capacity of this mold field equipment system is 48 tons/day, and the pH value of the water body is 10 to simulate the closed cooling water system of the blast furnace. Secondly, the demineralized water is used as the water body, the use time is 31 days, and the volume of the water body is one liter, and the usage amount of benzotriazole is 1500 mg. Furthermore, the corrosion rate of the standard carbon steel material was measured using a Sample Loop, and its flow rate was 2 m/s.

Application Example 5 and Comparative Application Example 3

In Application Example 5 and Comparative Application Example 3, the corrosion rate was measured in the same manner as in Application Example 4. The difference is that the usage amount of benzotriazole in Application Example 5 is 1250 mg, and Comparative Application Example 3 only uses demineralized water (excluding corrosion inhibitor composition), and the results of the aforementioned three are shown in Table 2 and Table 3. Show.

Application example 6

Application Example 6 is to add the corrosion inhibitor composition of Example 1 to the field equipment system, and based on the fact that the volume of water in the field equipment system is one liter, the usage amount of the organic amine compound is 1250 mg. This field equipment system has been added with the corrosion inhibitor composition of Comparative Example 1, and based on the volume of water in the field equipment system being one liter, the usage amount of sodium molybdate in the corrosion inhibitor composition of Comparative Example 1 is 273 mg, nitrous acid The usage amount of sodium was 261 mg, and the usage amount of methyl benzotriazole was 1.5 mg. The circulating water volume of this field equipment system is 5,000 tons/hour. Furthermore, the corrosion rates of standard carbon steel materials and standard copper materials were measured using an online corrosion rate measuring device with a water inflow of 48 tons/day, where the flow rate was 2 m/s, and the use time was 30 days.

Comparative application example 4

Comparative Application Example 4 In the same manner as in Application Example 6, the corrosion rate was measured. The difference is that the corrosion inhibitor composition of Comparative Application Example 4 only uses the corrosion inhibitor composition of Comparative Example 1, and the results of the above two are shown in Table 4 and Table 5.

註：N/A表示未進行試驗。 Table 1

Note: N/A means no test was performed.

註：應用例4進行兩次腐蝕率之試驗，第一次的結果為0.10mpy，第二次的結果為0.09mpy。 Table 2

Note: Application example 4 is used to conduct two corrosion rate tests, the first time is 0.10mpy, and the second time is 0.09mpy.

註：表3中之應用例4的水質分析係對應於表2中應用例4之第一次試驗。 table 3

Note: The water quality analysis of Application Example 4 in Table 3 corresponds to the first test of Application Example 4 in Table 2.

Table 4 Amount of organic amine compound used (mg) Corrosion rate (mpy) carbon steel copper first test second trial average value first test second trial average value Application example 6 1250 0.10 0.10 0.10 0.05 0.04 0.05 Comparative application example 4 1.5 0.22 0.21 0.22 0.13 0.11 0.12

table 5

Evaluation method

1. Corrosion rate test

(VI) 於式(VI)中，F為換算係數，其中標準碳鋼材料的換算係數為836.4，且標準銅材料的換算係數為772.6；W為標準碳鋼材料(或標準銅材料)之試驗前初始重量減去經過一使用時間後(即試驗後)標準碳鋼材料(或標準銅材料)之最終重量，其單位為公克(g)；D為使用時間，其單位為天數；腐蝕率的單位為密爾(mils penetration per year，mpy)。 The corrosion rate test referred to in the present invention is to use (or not use) the corrosion inhibitor composition in the water body of a water system. This body of water is in contact with standard carbon steel material (model C1010 Mild Steel) (or standard copper material (model CDA 443 Admiralty Br)), and after a period of use, the corrosion rate of carbon steel material (or copper material) is measured, To evaluate the anti-corrosion efficacy provided by the anti-corrosion composition. In addition, the treatment time of the corrosion inhibitor composition in the closed cooling water system can be judged according to the aforementioned corrosion rate. The qualified standard of the corrosion rate of standard carbon steel materials is not more than 1.0mpy, and the qualified standard of the corrosion rate of standard copper materials is is not more than 0.5mpy. The corrosion rate is calculated using the following formula (VI):

(VI) In formula (VI), F is the conversion factor, wherein the conversion factor of standard carbon steel material is 836.4, and the conversion factor of standard copper material is 772.6; W is the test of standard carbon steel material (or standard copper material) The initial weight minus the final weight of standard carbon steel material (or standard copper material) after a period of use (that is, after the test), the unit is gram (g); D is the use time, and the unit is days; The unit is mils penetration per year (mpy).

2. Test of water quality analysis

The test of water quality analysis referred to in the present invention is to use the anti-corrosion composition of Example 1 (or Comparative Example 1) in a water system, and after a period of use, measure the water body of the water system before adding the aforementioned anti-corrosion agent pH value, conductivity, ammonium ion (NH ₄ ⁺ ), sodium ion, calcium ion, chloride ion, total iron ion, nitrite concentration and COD (chemical oxygen demand) before and after the composition, and their measurement methods It is a method known to those skilled in the art to which the present invention pertains.

Please refer to Table 1, according to the results of the corrosion rate of standard carbon steel materials, compared with the comparative application examples 1 and 2 without the organic type anti-corrosion composition, the application examples 1 to 3 using the organic type anti-corrosion composition The water body of the cup and bottle system can reduce the corrosion rate of standard carbon steel materials. Based on the comparison of the corrosion rate of the comparative application example 2 and the three application examples using sodium hydroxide solution, the effect of reducing the corrosion rate comes from organic amine compounds. , not from sodium hydroxide or its increased alkalinity. Thus, it can be seen that the organic type corrosion inhibitor composition for closed cooling water system of the present invention can reduce the corrosion rate of carbon steel. In addition, according to the results of Application Example 1 to Application Example 3, as the amount of the organic amine compound used increases, the effect of reducing the corrosion rate is more significant.

Please refer to Table 2, according to the results of the corrosion rate, compared with the comparative application example 3 without the organic type corrosion inhibitor composition, the water body of the model field equipment system of the application examples 4 and 5 using the organic type corrosion inhibitor composition can be reduced Corrosion rates for standard carbon steel materials. In particular, the corrosion rate can be reduced to about 0.10mpy, which is about 0.1 times the acceptable standard of corrosion rate (not more than 1.0mpy) generally used for closed cooling water systems, so the organic type corrosion inhibitor composition has superior corrosion protection effect. . When the treatment time of the organic-type corrosion inhibitor compositions of application examples 4 and 5 in the closed cooling water system is 31 days, the corrosion rates of application examples 4 and 5 are far less than the qualified standard, so the organic-type anti-corrosion compositions of application examples 4 and 5 are used for 31 days. The corrosion inhibitor composition has the effect of increasing the treatment time of the closed cooling water system.

Next, from the results of two corrosion rate tests (0.10 mpy and 0.09 mpy) conducted in Application Example 4, it can be seen that the anti-corrosion effect of the organic type anti-corrosion composition has good reproducibility, and thus has the value of industrial application. Furthermore, from the results of the corrosion rates of Application Examples 4 and 5, it can be seen that the excellent anti-corrosion effect can be maintained even when the usage amount of the organic amine compound is reduced to 1250 mg.

Please refer to Table 3, according to the results of water quality analysis, after about 1 month (31 days), the pH value, sodium ion, calcium ion of the water body of the model field equipment system of Application Example 4 using the organic anti-corrosion composition And the concentration of chloride ions fluctuates very little. From this, it can be seen that the water quality stability of the water body of the model field equipment system of Application Example 4 is good, so the organic type corrosion inhibitor composition has no adverse effect on the water body.

In addition, according to the data of conductivity, after adding the organic anti-corrosion composition to the demineralized water, the increase of the conductivity comes from the sodium hydroxide. The added sodium hydroxide will increase the ion concentration and increase the conductivity of the water quality. . On the other hand, the increase of COD comes from the organic amine compounds in the organic type corrosion inhibitor composition. The addition of organic amine compounds will increase the consumption of the oxidant used to measure COD and increase the data of COD. Furthermore, according to the COD data on the 0th day and the 11th day of application example 4, the initial data of the COD data is larger than the subsequent data, which indicates that the organic amine compounds are adsorbed on the surface of carbon steel and copper materials, and the decrease The content of free organic amine compounds in water, so the COD data is reduced.

Further, according to the results of the total iron ion concentration, the total iron ion concentration of the water body of Application Example 4 is lower than that of the water body of Comparative Application Example 3, which echoes the results of the aforementioned corrosion rate test, that is, the organic type corrosion inhibitor composition has superior properties. Anti-corrosion effect. On the other hand, the change of the ammonium ion concentration in the water of Application Example 4 is small, which indicates that the organic amine compound is not degraded, that is, the stability of the organic amine compound is good. In other words, organic amine compounds can tolerate the water temperature of closed cooling water systems without thermal cracking.

Please refer to Table 4, according to the results of the corrosion rate, compared with the comparative application example 4 using only the inorganic type corrosion inhibitor composition, the water body of the water system of the application example 6 additionally using the organic type corrosion inhibitor composition reduces the standard carbon steel material and the corrosion rate of the standard copper material, which is about 50% of the corrosion rate of Comparative Application Example 4. In other words, compared with the inorganic type corrosion inhibitor composition, the organic type corrosion inhibitor composition can greatly reduce the corrosion rate of carbon steel and copper at the same time. In particular, the inorganic type anti-corrosion composition contains three anti-corrosion agents (molybdate, nitrite, and methyl benzotriazole), while the organic-type anti-corrosion composition contains only one anti-corrosion agent (ie, organic amine compound) . Therefore, the organic-type anti-corrosion composition has superior anti-corrosion effect of carbon steel and copper.

In addition, since molybdate is expensive and biologically toxic, and nitrite easily leads to water quality optimization and is carcinogenic, the organic corrosion inhibitor composition has the advantages of low price and good environment. In other words, the organic amine compound of the present invention is very suitable for closed cooling water system, and has the potential to replace the existing inorganic type corrosion inhibitor. In addition, the organic amine compound of the present invention can also be added to the inorganic type anti-corrosion agent to enhance its anti-corrosion effect.

In addition, according to the qualified standard of corrosion rate, and based on the results of the corrosion protection rate of Application Example 6, the treatment time of the organic-type corrosion inhibitor composition of Application Example 6 in the closed cooling water system was 30 days. When the treatment time of the organic anti-corrosion composition of Application Example 6 in the closed cooling water system is 30 days, the corrosion rates of carbon steel and copper in Application Example 6 are far less than the qualified standard, so the organic anti-corrosion composition of Application Example 6 is composed of The material has the effect of increasing the treatment time of the closed cooling water system.

Please refer to Table 5. According to the results of nitrite concentration, the nitrite concentration of the water body of the water system using the inorganic type corrosion inhibitor composition varies greatly, especially the data on the 20th day, which is about the data of other use times 0.5 times. From this, it can be seen that the stability of the inorganic type corrosion inhibitor composition in the water system is not good. Therefore, the inorganic type anti-corrosion composition is less stable than the organic type anti-corrosion composition in a closed cooling water system.

To sum up, the organic corrosion inhibitor composition for closed cooling water system of the present invention comprises demineralized water, alkali metal hydroxide and organic amine compound. The organic amine compound has an aromatic ring structure containing 1 to 3 nitrogen atoms. This aromatic ring structure can help organic amine compounds to be stably adsorbed on the surface of carbon steel and copper materials, so as to reduce the consumption of organic amine compounds, thereby increasing the processing time of organic anti-corrosion compositions in closed cooling water systems , and reduce the corrosion rate of carbon steel and copper materials. Accordingly, the use method of the organic type corrosion inhibitor composition of the present invention can reduce the corrosion rate of carbon steel and copper in the water body of the closed cooling water system.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention. Anyone with ordinary knowledge in the technical field to which the present invention pertains can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the appended patent application.

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Claims (7)

An organic type corrosion inhibitor composition for closed cooling water system, comprising: demineralized water; alkali metal hydroxides; and An organic amine compound, wherein the organic amine compound has an aromatic cyclic structure containing 1 to 3 nitrogen atoms, and the molecular weight of the organic amine compound is 60 g/mole to 280 g/mole; Wherein based on the weight of the organic type corrosion inhibitor composition is 100 weight percent, a content of the demineralized water is 50 weight percent to 80 weight percent, and a content of the alkali metal hydroxide is 10 weight percent to 25 weight percent, And a content of the organic amine compound is 10 weight percent to 25 weight percent. The organic type corrosion inhibitor composition for a closed cooling water system according to claim 1, wherein the cracking temperature of the organic amine compound is equal to or greater than 100°C. A method of using an organic type corrosion inhibitor composition, comprising: Add the organic type corrosion inhibitor composition for closed cooling water system as described in claim 1 to a water body of the closed cooling water system; The volume of the water body based on the closed cooling water system is one liter, and one of the organic amine compounds is used in an amount of 1000 mg to 2000 mg. The use method of the organic type corrosion inhibitor composition according to claim 3, wherein the pH value of the water body is 8.5 to 10.5. The method for using the organic-type corrosion inhibitor composition according to claim 3, wherein the temperature of the water body is 50°C to 60°C. The method of using the organic-type anti-corrosion composition as claimed in claim 3, wherein a treatment time of the organic-type anti-corrosion composition in the closed cooling water system is equal to or greater than 30 days. The method for using the organic-type corrosion inhibitor composition according to claim 3, wherein the water body has a carbon steel corrosion rate of not more than 1.0 mpy and/or a copper corrosion rate of not more than 0.5 mpy.