Corrosion inhibitor composition and application thereof, absorption liquid and application thereof

Abstract

The present invention relates to the field of gas purification, and discloses a corrosion inhibitor composition, characterized in that the corrosion inhibitor composition contains a triazine compound, a pyrrolidone compound and polyaniline. The corrosion inhibitor composition provided by the present invention does not contain sodium vanadate, vanadium pentoxide, sodium metavanadate or other vanadium compounds, and can improve the corrosion inhibition performance of the desulfurization and decarbonization solution while making the desulfurization and decarbonization solution and the operation process more green and safe.

Description

Technical Field

[0001] The invention relates to the field of gas purification, and in particular to a corrosion inhibitor composition and application thereof, an absorption liquid and application thereof. Background Art

[0002] Industrially, the process technologies such as alcohol amine method, liquid desulfurizer, hot potash are widely used to remove H2S and CO2 in gas mixture, such as process gases or waste gases such as natural gas, biogas, refinery gas, synthetic ammonia, coke oven gas, blast furnace gas, etc. In the process of removing H2S and CO2 using the above method, it is inevitable that the corrosion of pipelines and equipment occurs, resulting in destructive behaviors such as pipeline thinning, perforation leakage, and equipment failure. CN101091864A, CN103143236A and CN108568189A all propose to add sodium vanadate, vanadium pentoxide or sodium metavanadate in the desulfurization and decarbonization solution to increase the corrosion inhibition performance of the solution and reduce the corrosion degree of steel. However, sodium vanadate, vanadium pentoxide or sodium metavanadate all contain heavy metal vanadium, which threatens the health of operators in the desulfurization and decarbonization operation. In addition, when the desulfurization and decarbonization solution is abandoned or leaked, the vanadium in the desulfurization and decarbonization solution may enter the water body, thereby polluting the water body. Therefore, it is of great significance to find corrosion inhibitors that do not contain vanadium compounds in order to improve the corrosion inhibition performance of desulfurization and decarbonization solutions. Summary of the invention

[0003] The purpose of the present invention is to provide a corrosion inhibitor which does not contain sodium vanadate, vanadium pentoxide or sodium metavanadate or other vanadium compounds, in order to solve the problem that the existing desulfurization and decarbonization solution contains sodium vanadate, vanadium pentoxide or metavanadic acid, which causes water pollution and endangers the health of operators, so as to improve the corrosion inhibition performance of the desulfurization and decarbonization solution and make the desulfurization and decarbonization solution and the operation process more green and safe.

[0004] In order to achieve the above object, the first aspect of the present invention provides a corrosion inhibitor composition, characterized in that the corrosion inhibitor composition contains a triazine compound, a pyrrolidone compound and polyaniline.

[0005] The second aspect of the present invention provides a use of the above-mentioned corrosion inhibitor composition in gas desulfurization and decarbonization.

[0006] A third aspect of the present invention provides an absorbing liquid, characterized in that the absorbing liquid contains the above-mentioned corrosion inhibitor composition.

[0007] A fourth aspect of the present invention provides a use of the above-mentioned absorption liquid in gas purification.

[0008] Through the above technical scheme, the corrosion inhibitor composition and its application, the absorption liquid and its application provided by the present invention achieve the following beneficial effects:

[0009] The corrosion inhibitor composition of the desulfurization and decarbonization solution proposed by the present invention can significantly enhance the corrosion inhibition performance of the desulfurization and decarbonization solution on steel. Moreover, the corrosion inhibitor composition does not contain commonly used vanadium compounds, making production operations and waste liquid disposal greener and safer, and avoiding environmental pollution. DETAILED DESCRIPTION

[0010] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0011] The first aspect of the present invention provides a corrosion inhibitor composition, characterized in that the corrosion inhibitor composition contains a triazine compound, a pyrrolidone compound and polyaniline;

[0012] Wherein, the content of the triazine compound is 35-80wt%, the content of the pyrrolidone compound is 15-40wt%, and the content of the polyaniline is 5-20wt%.

[0013] In the present invention, when the components of the corrosion inhibitor composition meet the above ranges, the corrosion inhibition rate of carbon steel can be significantly reduced.

[0014] According to the present invention, based on the total weight of the composition, the content of the triazine compound is 50-70wt%, the content of the pyrrolidone compound is 20-30wt%, and the content of the polyaniline is 7.5-15wt%.

[0015] According to the present invention, the triazine compound is selected from hydroxyethyl hexahydro-s-triazine and / or hydroxymethyl hexahydro-s-triazine.

[0016] According to the present invention, the pyrrolidone compound is selected from N-methylpyrrolidone and / or N-ethylpyrrolidone.

[0017] According to the present invention, the viscosity average molecular weight of the polyaniline is 1000-5000.

[0018] In the present invention, when the corrosion inhibitor composition contains hydroxyethyl hexahydro-s-triazine, N-methylpyrrolidone and polyaniline, the corrosion inhibitor composition is more green and safe when used.

[0019] A second aspect of the present invention provides an application of the above-mentioned corrosion inhibitor composition in gas desulfurization and decarbonization.

[0020] According to the present invention, the gas desulfurization and decarbonization is a desulfurization and decarbonization solution containing acidic components.

[0021] In the present invention, the acidic components refer to components containing acidic gases such as CO2, H2S, COS and mercaptans.

[0022] A third aspect of the present invention provides an absorbing liquid, characterized in that the absorbing liquid contains the above-mentioned corrosion inhibitor composition.

[0023] In the present invention, the absorption liquid contains the above-mentioned corrosion inhibitor composition, which can significantly improve the corrosion inhibition performance during the desulfurization and decarbonization process.

[0024] According to the invention, the absorption liquid further comprises a main absorption component.

[0025] In the present invention, there is no special requirement for the main absorption component, which can be any main absorption component in the prior art, for example, methyldiethanolamine (MDEA), K2CO3, ethanolamine (MEA), tert-butylaminoethoxyethanol (TBEE) and a liquid desulfurizer.

[0026] In the present invention, when the main absorbent is the above-mentioned substance, H2S and CO2 in the exhaust gas can be effectively removed, and the corrosion inhibitor composition provided by the first aspect of the present invention can be compounded to efficiently remove H2S and CO2 in the exhaust gas while slowing down the corrosion rate of carbon steel.

[0027] According to the present invention, based on the total weight of the absorption liquid, the amount of the main absorption component is 25-50wt%, and the amount of the corrosion inhibitor composition is 0.175-0.7wt% of the main absorption component.

[0028] Furthermore, the absorption liquid may be a desulfurization and decarbonization solution.

[0029] A fourth aspect of the present invention provides a use of the above-mentioned absorption liquid in gas purification.

[0030] According to a preferred embodiment of the present invention:

[0031] The absorption liquid is a 25-50wt% MDEA solution and a 0.175-0.7wt% corrosion inhibitor composition, wherein, based on the total weight of the corrosion inhibitor composition, 35-80wt% of hydroxyethyl hexahydrotriazine, 5-20wt% of polyaniline, and 15-40wt% of N-methylpyrrolidone. A 20# hanging plate is placed in the absorption liquid, and a mixed gas consisting of H2S, CO2 and N2 is introduced. The mixed gas overflows from the absorption liquid in a bubbling manner, and is condensed and cooled by a condenser before exiting the dynamic test system for corrosion inhibition performance. The condensed coolant returns to the hanging plate absorption liquid. The corrosion inhibition performance test pressure is normal pressure, the absorption liquid temperature is 40°C, the mixed gas flow rate is 400mL / min, and the mixed gas composition is H2S with an average value of 1015mg / Nm 3, CO2 volume fraction 5.1%, the rest is N2. The corrosion rate after 72h dynamic test was recorded.

[0032] The present invention will be described in detail below by way of examples. In the following examples,

[0033] The corrosion rate of carbon steel is measured by the dynamic method of coupon test;

[0034] MDEA solution, MDEA content> 99.5wt%;

[0035] Hydroxyethyl hexahydro-s-triazine solution, commercially available at a content of 70 wt%, purified to 90 wt% by vacuum distillation and used in the present invention;

[0036] N-methylpyrrolidone solution, N-methylpyrrolidone content> 99wt%;

[0037] Polyaniline, self-made by emulsion method, viscosity-average molecular weight 1000-5000.

[0038] Reference ratio

[0039] A 35wt% methyldiethanolamine (MDEA) solution was used as the absorption liquid. A 20# hanging piece was placed in the absorption liquid and a mixed gas containing H2S, CO2 and N2 was introduced. The mixed gas overflowed from the absorption liquid in a bubbling manner and was condensed and cooled by a condenser tube before exiting the dynamic test system for corrosion inhibition performance. The condensed coolant returned to the absorption liquid of the hanging piece. The corrosion inhibition performance test pressure was normal pressure, the absorption liquid temperature was 40°C, the mixed gas flow rate was 400mL / min, and the mixed gas composition was H2S with an average value of 1015mg / Nm 3 , CO2 volume fraction 5.1%, the rest is N2. The corrosion rate after 72h dynamic test is recorded, see Table 1.

[0040] Example 1

[0041] A 35wt% mass fraction of methyldiethanolamine (MDEA) solution is used as the absorption liquid, and a corrosion inhibitor composition accounting for 0.35wt% of the total mass of the absorption liquid is added. Among them, based on the total weight of the corrosion inhibitor composition, 68wt% of hydroxyethyl hexahydrotriazine, 8wt% of polyaniline, and 24wt% of N-methylpyrrolidone are used. A hanging piece made of 20# material is placed in the absorption liquid, and a mixed gas composed of H2S, CO2 and N2 is introduced. The mixed gas overflows from the absorption liquid in a bubbling manner, and is condensed and cooled by a condenser tube before exiting the dynamic test system for corrosion inhibition performance. The condensed coolant returns to the absorption liquid of the hanging piece. The corrosion inhibition performance test pressure is normal pressure, the absorption liquid temperature is 40°C, the mixed gas flow rate is 400mL / min, and the mixed gas composition is H2S with an average value of 1015mg / Nm 3, CO2 volume fraction 5.1%, the rest is N2. The corrosion rate after 72h dynamic test is recorded, see Table 1.

[0042] Example 2

[0043] The same as Example 1, except that the corrosion inhibitor composition accounts for 0.525wt% of the total absorption liquid. The corrosion rate after 72h dynamic test was recorded by hanging test, see Table 1.

[0044] Example 3

[0045] The same as Example 1, except that, based on the total weight of the corrosion inhibitor composition, 60wt% of hydroxyethyl hexahydro-s-triazine, 10wt% of polyaniline, and 30wt% of N-methylpyrrolidone, the corrosion inhibitor composition accounts for 0.35wt% of the total absorption liquid. The corrosion rate after 72h dynamic test was recorded by hanging test, as shown in Table 1.

[0046] Example 4

[0047] The same as Example 1, except that, based on the total weight of the corrosion inhibitor composition, 60wt% of hydroxyethyl hexahydro-s-triazine, 10wt% of polyaniline, and 30wt% of N-methylpyrrolidone, the corrosion inhibitor accounts for 0.175wt% of the total absorption liquid. The corrosion rate after 72h dynamic test was recorded by hanging test, as shown in Table 1.

[0048] Example 5

[0049] The same as Example 1, except that, based on the total weight of the corrosion inhibitor composition, 55wt% of hydroxyethyl hexahydro-s-triazine, 15wt% of polyaniline, and 30wt% of N-methylpyrrolidone, the corrosion inhibitor accounts for 0.35wt% of the total absorption liquid. The corrosion rate after 72h dynamic test was recorded by hanging test, as shown in Table 1.

[0050] Example 6

[0051] The same as Example 1, except that, based on the total weight of the corrosion inhibitor composition, 68wt% of hydroxyethyl hexahydro-s-triazine, 8wt% of polyaniline, and 24wt% of N-methylpyrrolidone, the corrosion inhibitor accounts for 0.105wt% of the total absorption liquid. The corrosion rate after 72h dynamic test was recorded by hanging test, as shown in Table 1.

[0052] Comparative Example 1

[0053] The same as Example 1, except that the hydroxyethyl hexahydro-s-triazine in the corrosion inhibitor was replaced by imidazoline, and the corrosion rate after 72h dynamic test was recorded, as shown in Table 1.

[0054] Comparative Example 2

[0055] The same as Example 1, except that N-methylpyrrolidone is not contained, and the corrosion rate after 72h dynamic test is recorded, see Table 1.

[0056] Comparative Example 3

[0057] The same as Example 1, except that polyaniline is not contained, and the corrosion rate after 72h dynamic test is recorded, see Table 1.

[0058] Comparative Example 4

[0059] The same as Example 1, except that hydroxyethyl hexahydro-s-triazine is not contained, and the corrosion rate after 72h dynamic test is recorded, see Table 1.

[0060] Comparative Example 5

[0061] The same as Example 1, except that, based on the total weight of the corrosion inhibitor composition, 20 wt% of hydroxyethyl hexahydro-s-triazine, 5 wt% of polyaniline, and 75 wt% of N-methylpyrrolidone, the corrosion inhibitor accounts for 0.35 wt% of the total absorption liquid. The corrosion rate after 72 h of dynamic test was recorded by hanging test, as shown in Table 1.

[0062] Test Case

[0063] Referring to the national standard JB / T 7901-2001 "Method for laboratory uniform corrosion full immersion test of metal materials" for metal materials and the petroleum and natural gas industry standard SY / T 5273-2000 "Method for evaluating the performance of corrosion inhibitors for oilfield produced water", the corrosion inhibition performance was determined dynamically using the hanging plate test.

[0064] Table 1

[0065]

[0066]

[0067] It can be seen from the results in Table 1 that after using the corrosion inhibitor composition provided by the present application in the traditional desulfurization and decarbonization solution, the corrosion inhibition performance is significantly improved, the corrosion inhibition rate is significantly reduced, and a significant corrosion inhibition effect is achieved. This helps to improve the corrosion resistance of 20# carbon steel when used for desulfurization and decarbonization, increase the service life of pipelines and equipment, and reduce failures caused by corrosion.

[0068] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A corrosion inhibitor composition, characterized in that: The corrosion inhibitor composition consists of a triazine compound, a pyrrolidone compound and polyaniline; Wherein, based on the total weight of the composition, the content of the triazine compound is 50-70wt%, the content of the pyrrolidone compound is 20-30wt%, the content of the polyaniline is 7.5-15wt%, and the sum of the contents of the components in the composition is 100wt%.

2. The composition according to claim 1, wherein The triazine compound is selected from hydroxyethyl hexahydro-s-triazine and / or hydroxymethyl hexahydro-s-triazine.

3. The composition according to claim 1, wherein The pyrrolidone compound is N-methylpyrrolidone and / or N-ethylpyrrolidone.

4. The composition according to any one of claims 1 to 3, wherein The viscosity average molecular weight of the polyaniline is 1000-5000.

5. Use of the corrosion inhibitor composition according to any one of claims 1 to 4 in gas desulfurization and decarbonization.

6. The use according to claim 5, wherein: The corrosion inhibitor composition is used in a desulfurization and decarbonization solution containing acidic components.

7. An absorption liquid, characterized in that: The absorption liquid comprises the corrosion inhibitor composition according to any one of claims 1 to 4.

8. The absorbing liquid according to claim 7, wherein The absorption liquid also includes a main absorption component.

9. The absorbing liquid according to claim 8, wherein Based on the total weight of the absorption liquid, the main absorption component is used in an amount of 25-50wt%, and the corrosion inhibitor composition is used in an amount of 0.175-0.7wt%.

10. Use of the absorption liquid according to any one of claims 7 to 9 in gas purification.

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