Anticorrosion composition as well as preparation method and application thereof

Abstract

The invention relates to the technical field of packing, and particularly discloses an anti-corrosion composition as well as a preparation method and application thereof. The anti-corrosion composition comprises the following raw materials: active metal powder, acid salt and water, the preparation method comprises the step of mixing the active metal powder, the acid salt and the deionized water. The anti-corrosion composition can be used for soaking the packing and has the advantage that the corrosion effect of the packing on the valve rod can be reduced.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of packing, in particular to an anticorrosive composition and a preparation method and application thereof. BACKGROUND

[0002] The packing is also called sealing packing, and is usually woven by soft linear objects and mainly made of graphite and various fibers. In valve sealing, one group is usually used in cooperation with a valve rod to play a key sealing role.

[0003] In the production process of the packing, sulfuric acid and nitric acid are used for softening treatment, so that acidic substances are left in the treated packing. Since the packing is closely attached to the valve rod, the acidic substances continuously corrode the valve rod, so that water flowing through the corroded part of the valve rod leaks out, the sealing property of the valve is reduced, and thus the normal operation and safety of the equipment are affected. SUMMARY

[0004] In order to reduce the corrosion of the packing to the valve rod, the application provides an anticorrosive composition and a preparation method and application thereof.

[0005] In a first aspect, the application provides an anticorrosive composition, which adopts the following technical scheme: The anticorrosive composition comprises the following raw materials: active metal powder, acid salt and water.

[0006] Since the packing is subjected to softening treatment by sulfuric acid and nitric acid in the production process, acidic substances are left in the treated packing, and the reduction of the active metal powder and the electrochemical protection of the zinc salt are used to neutralize the acidic substances left in the packing, so that the corrosion of the packing to the valve rod is reduced.

[0007] Preferably, the weight ratio of the active metal powder, the acid salt and the water is 1:(2-4):(0.02-0.04).

[0008] The above mass ratio can optimize the content of each component, which is beneficial to fully neutralize the acidic substances and reduce the corrosion of the packing to the valve rod.

[0009] Preferably, the active metal powder is zinc powder.

[0010] Since the zinc ion is a more active metal than iron, it can react with the residual acid radical to generate hydrogen, thereby consuming the acid radical and reducing the corrosion of the packing to the valve rod, and the selection of the zinc powder can effectively reduce the cost.

[0011] Preferably, the acid salt is zinc nitrate.

[0012] Since zinc powder is a metallic element, it is difficult to dissolve in water at room temperature and it is not easy to directly dissociate into zinc ions. Therefore, it is difficult for it to diffuse into the packing and react with acidic substances. Zinc nitrate, as a soluble zinc salt, can dissociate into a large amount of zinc ions in water and come into contact with residual acidic substances. At the same time, zinc powder reacts with acidic substances to generate zinc ions, further replenishing the zinc ion concentration in the solution. The synergistic effect of the two is conducive to the effective entry of zinc ions into the packing.

[0013] In a second aspect, the present application provides a method for preparing an antiseptic composition, which adopts the following technical solution: A method for preparing an anti-corrosion composition comprises the following steps: mixing active metal powder, acid salt and deionized water.

[0014] Preferably, the acid salt is dissolved in deionized water and heated, followed by the addition of zinc powder.

[0015] Since dissolving zinc nitrate in deionized water and heating it first is conducive to the complete dissolution of zinc nitrate and can provide initial zinc ions, the subsequent addition of zinc powder can make the zinc powder evenly dissolved in the solution, replenish zinc ions, and is conducive to forming a dynamic balance.

[0016] Preferably, the heating temperature is 50°C-70°C.

[0017] Controlling the heating temperature at 50°C-70°C can not only fully dissolve the zinc nitrate, but also moderately activate the surface of the zinc powder. At the same time, zinc nitrate is not easily decomposed or the solution evaporates excessively due to excessive temperature, which is beneficial to accelerate the reaction rate of zinc nitrate and zinc powder and improve production efficiency.

[0018] In a third aspect, the present application provides a packing, which adopts the following technical solution: A packing is taken out after being soaked in the antiseptic composition.

[0019] Preferably, the soaking time is 65-96 hours.

[0020] Since the acidic substances remaining inside the packing can exist in the form of adsorption, binding or diffusion into the gaps of the packing, if the reaction time is too short, the zinc ions may only react quickly with the acidic substances on the surface or shallow layer, and it is difficult to fully diffuse into the packing, resulting in the deep acidic substances cannot be completely neutralized. Reacting the packing with the anti-corrosion composition for 65-96 hours can facilitate sufficient contact and diffusion time between the zinc ions and the acidic substances, allowing the reaction to gradually penetrate into the packing and consume the residual acidic substances.

[0021] In summary, this application has the following beneficial effects: 1. During the production process, the packing is softened with sulfuric acid and nitric acid, and acidic substances will remain inside the packing after treatment. The reducing property of the active metal powder and the electrochemical protection of the zinc salt can synergistically neutralize the acidic substances remaining inside the packing, which is beneficial for the packing to be less likely to corrode the valve stem.

[0022] 2. When the weight ratio of active metal powder, zinc salt and deionized water is 1: (2-4): (20-40), the content of each component can be optimized, which is conducive to maintaining sufficient neutralization of acidic substances, making it less likely to cause excessive components, and is conducive to further reducing the corrosion of the packing on the valve stem.

[0023] 3. As zinc ions are more active metals than iron, they can react with residual acid radicals to generate hydrogen, thereby consuming the acid radicals and making the packing less likely to corrode the valve stem. At the same time, the selection of zinc powder can effectively reduce costs. DETAILED DESCRIPTION

[0024] The present application is further described in detail below in conjunction with Examples 1 to 7 and Comparative Examples 1 to 2.

[0025] Example 1 An anti-corrosion composition comprises the following raw materials: zinc powder, zinc nitrate and deionized water.

[0026] Specifically, the preparation method of the antiseptic composition comprises the following steps: Dissolve zinc nitrate in deionized water, heat to 60°C, add zinc powder while stirring, then cool to 27.5°C and let stand for 4.5 hours to obtain an anticorrosive composition, wherein the weight ratio of zinc powder, zinc nitrate and deionized water is 1:3:30.

[0027] The untreated packing was immersed in the antiseptic composition for 72 hours, and then taken out to obtain the packing.

[0028] Example 2-Example 3 The difference from Example 1 is that the weight ratio of the antiseptic composition is different, as shown in Table 1.

[0029] Table 1 Weight ratio of the antiseptic composition in Examples 1 to 3 Example 1 Example 2 Example 3 zinc powder 1 1 1 Zinc nitrate 3 2 4 Deionized water 30 40 20 Example 4-Example 5 The difference from Example 1 is that the soaking time of the packing in the antiseptic composition is different, as shown in Table 2.

[0030] Table 2 Reaction timetable of packing and anticorrosive composition in Examples 1 and 4-5 Example 1 Example 4 Example 5 Reaction time 72 65 96 Example 6 The difference from Example 1 is that the preparation method of the corrosion protection composition is different, specifically: The zinc powder is first mixed with deionized water, heated to 50°C, and then zinc nitrate is added while stirring. Subsequently, it is cooled to 27.5°C and left to stand for 4.5h to obtain the corrosion protection composition.

[0031] Example 7 The difference from Example 1 is that the weight ratio of zinc powder, zinc nitrate and deionized water is 1.5:3:30 Comparative Example 1 The difference from Example 1 is that no zinc powder is added.

[0032] Comparative Example 3 The difference from Example 1 is that the packing is soaked in the corrosion protection composition for 24h.

[0033] Performance test I. Corrosion resistance Three samples are taken from Example 1-Example 6 and Comparative Example 1-Comparative Example 3, respectively, and assembled with 304 stainless steel valve stems. After six months of use, the static leakage rate is determined according to the ISO 5208:2015 "Industrial Valves-Pressure Test for Metal Valves" standard, the dynamic cumulative leakage is determined according to the API 622:2018 "Type Test for Packer Emission of Process Valves" standard, and the valve stem corrosion depth is determined according to the ASTM G46-94 "Standard Guide for Examination and Evaluation of Pitting Corrosion" standard.

[0034] The test data is shown in Table 3.

[0035] Table 3 Corrosion resistance test table of Example 1-Example 6 and Comparative Example 1-Comparative Example 3 Static leakage rate (mL / min) Dynamic cumulative leakage (ppm) Valve stem corrosion depth (μm) Example 1 0.02 15 5 Example 2 0.03 20 8 Example 3 0.025 18 6 Example 4 0.023 16 5.5 Example 5 0.022 14 4.8 Example 6 0.05 22 9 Example 7 0.18 34 12.8 Comparative Example 1 0.5 200 55 Comparative Example 2 0.15 88 25 From Example 1 and Comparative Example 1 and Table 3, it can be seen that the static leakage rate, dynamic cumulative leakage and valve stem corrosion depth of Comparative Example 1 are all greatly increased compared with Example 1. Therefore, compared with not adding zinc powder, soaking the packing in the corrosion protection composition with zinc powder can effectively reduce the corrosion of the packing on the valve stem after long-term use.

[0036] The reason is that zinc ions, as a more active metal than iron, can neutralize the residual acid radicals to generate hydrogen, thereby consuming the acid radicals, so that the packing is not easy to corrode the valve rod. Zinc nitrate, as a soluble zinc salt, can dissociate a large amount of zinc ions in water, contact with residual acidic substances. At the same time, zinc powder reacts with acidic substances to generate zinc ions, further supplementing the zinc ion concentration in the solution. The two work together to help zinc ions effectively enter the packing.

[0037] As can be seen from the combination of Example 1 and Example 7 and Table 3, the static leakage rate, dynamic cumulative leakage and valve rod corrosion depth of Comparative Example 2 are also greatly increased compared with Example 1, which shows that the excessive addition of zinc powder also affects the corrosion reduction of the packing on the valve rod, and the weight fraction ratio of zinc powder, zinc nitrate and deionized water in Example 1 is optimal.

[0038] The reason is that when the weight fraction ratio of zinc powder, zinc nitrate and deionized water is 1:3:30, the content of each component can be optimized, the zinc ion concentration is moderate, which is conducive to maintaining sufficient neutralization of acidic substances, so that it is not easy to cause excessive components, and it is conducive to further reducing the corrosion of the packing on the valve rod.

[0039] As can be seen from the combination of Example 1 and Comparative Example 3 and Table 3, the static leakage rate, dynamic cumulative leakage and valve rod corrosion depth of Comparative Example 3 are also greatly increased compared with Example 1, which shows that the time of the packing soaked in the corrosion-resistant composition is too short, which also affects the corrosion reduction of the packing on the valve rod, and the time of the packing soaked in the corrosion-resistant composition in Example 1 is optimal.

[0040] The reason is that the residual acidic substances in the packing can exist in the form of adsorption, combination or diffusion into the voids of the packing. If the reaction time is too short, the zinc ions may only react rapidly with the surface or shallow acidic substances, and it is difficult to fully diffuse into the interior of the packing, so that the deep acidic substances cannot be completely neutralized. The packing is reacted with the corrosion-resistant composition for 72h, which can provide sufficient contact and diffusion time for zinc ions and acidic substances, so that the reaction penetrates into the interior of the packing and consumes the residual acidic substances.

[0041] As can be seen from the combination of Example 1 and Examples 2-3 and Table 3, the static leakage rate, dynamic cumulative leakage and valve rod corrosion depth of Examples 2 and 3 are increased compared with Example 1, which shows that the weight fraction ratio of the corrosion-resistant composition affects the corrosion reduction of the packing on the valve rod, and the weight fraction ratio of zinc powder, zinc nitrate and deionized water in Example 1 is optimal.

[0042] Combining Example 1 with Example 4-Example 5 and Table 3, it can be seen that relative to Example 1, the static leakage rate, dynamic cumulative leakage, and valve stem corrosion depth in Example 4 and Example 5 are also increased. This shows that the reaction time between the packing and the anti-corrosion composition affects the ability of the packing to reduce the corrosion effect on the valve stem, and the reaction time between the packing and the anti-corrosion composition in Example 1 is optimal.

[0043] Combining Example 1 and Example 6 with Table 3, it can be seen that relative to Example 1, the static leakage rate, dynamic cumulative leakage, and valve stem corrosion depth in Example 6 are all increased, which indicates that the order of adding the raw materials in the anti-corrosion composition affects the packing's ability to reduce corrosion of the valve stem.

[0044] The reason is that dissolving zinc nitrate in deionized water and heating it first is conducive to the complete dissolution of zinc nitrate and can provide initial zinc ions. Then adding zinc powder can make the zinc powder dissolve evenly in the solution, replenish zinc ions, and help form a dynamic balance.

[0045] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. An antiseptic composition, characterized in that Including the following ingredients: Active metal powder, acid salt and water.

2. An antiseptic composition according to claim 1, characterized in that: The weight ratio of the active metal powder, acid salt and water is 1: (2-4): (20-40).

3. The antiseptic composition according to claim 1, characterized in that: The active metal powder is zinc powder.

4. The antiseptic composition according to claim 1, characterized in that: The acid salt is zinc nitrate.

5. The method for preparing an antiseptic composition according to any one of claims 1 to 4, characterized in that: The following steps are involved: Mix active metal powder, acid salt and deionized water.

6. The method for preparing an antiseptic composition according to claim 5, characterized in that: The acid salt was dissolved in deionized water and heated, followed by the addition of zinc powder.

7. The method for preparing an antiseptic composition according to claim 6, characterized in that: The heating temperature is 50°C-70°C.

8. A packing characterized by: The product is taken out after being soaked in the antiseptic composition according to any one of claims 1 to 4.

9. The packing according to claim 8, characterized in that: The soaking time is 65-96 hours.