A high-efficiency composite desulfurization and decarbonization solvent and its preparation method

Abstract

The invention discloses a highly efficient composite desulfurization and decarbonization solvent and a preparation method thereof, belonging to the technical field of natural gas purification and treatment, and the highly efficient composite desulfurization and decarbonization solvent comprises the following components in parts by weight: 75 to 80 parts of a composite amine agent, 2 to 10 parts of an emulsifier, 0.2 to 0.5 parts of a corrosion inhibitor, 0.1 to 0.2 parts of a promoter, and 0.1 to 0.2 parts of a defoamer, wherein the composite amine agent is mixed with N-methyldiethanolamine, a triazine ring structure, a secondary alcohol amine, and a primary alcohol amine in a mass ratio of 6 to 10:2 to 3:1:1. The desulfurization and decarbonization solvent prepared by the present invention is used for a natural gas desulfurization and decarbonization treatment process, and after testing, the H2S removal rate is ≥99.98%; the CO2 removal rate is ≥66.85%; and the total organic sulfide removal rate is ≥94.80%.

Description

Technical Field

[0001] The invention belongs to the technical field of natural gas purification and treatment, and specifically relates to a high-efficiency composite desulfurization and decarbonization solvent and a preparation method thereof. Background Art

[0002] The natural gas extracted from the wellhead contains H 2 S, CO 2 and organic sulfides (carbonyl sulfide, mercaptan), these three are generally called acid gases, which can corrode equipment and pipelines during processing, storage and transportation. At the same time, natural gas containing acid gases will pollute the environment when used as chemical raw materials. Therefore, when the acid gas content in natural gas exceeds the commodity gas quality index or pipeline transportation requirements, the natural gas must be desulfurized and decarbonized to remove the acid gas content to within the allowable range.

[0003] At present, the main methods for natural gas desulfurization and decarbonization are physical solvent method and chemical solvent method. This application mainly improves and innovates the chemical solvent method. The chemical solvent method uses acidic gas to react with chemical solvent to achieve the purpose of removal. Commonly used chemical solvents are alcohol amine solvents, and commonly used alcohol amine solvents are monoethanolamine, diethanolamine, methyldiethanolamine, etc. Among them, monoethanolamine is a primary alcohol amine. Primary alcohol amine has a high 2 S can also remove part of the CO in the raw gas 2 However, primary alcohol amines are prone to foaming and degradation, and their 2 Side reactions will occur to generate degradation products that are difficult to regenerate, such as oxazolidinone, which will cause the solvent to reduce or lose its desulfurization ability; diethanolamine is a secondary alcohol amine, and secondary alcohol amines have a strong affinity for H 2 S and CO 2 It has excellent removal performance, but its 2 S and CO 2 It does not have selective removal properties, and its removal efficiency for organic sulfides is low; methyldiethanolamine is a tertiary alcoholamine, which has good chemical stability and contains H 2 S and CO 2 H can be selectively removed from the raw gas 2 S, but it cannot remove CO deeply 2 In view of the fact that primary alcoholamines, secondary alcoholamines and tertiary alcoholamines commonly used in the alcoholamine method of the chemical solvent method each have their own advantages and disadvantages, the present invention aims to improve the desulfurization and decarbonization effects of the configured desulfurization and decarbonization solvent by reasonable compounding and improvement. Summary of the invention

[0004] The invention provides a high-efficiency composite desulfurization and decarbonization solvent and a preparation method thereof, aiming to improve the desulfurization and decarbonization effects of the composite desulfurization and decarbonization solvent.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A highly efficient composite desulfurization and decarbonization solvent comprises the following components in parts by weight:

[0007] 75-80 parts of complex amine, 2-10 parts of emulsifier, 0.2-0.5 parts of corrosion inhibitor, 0.1-0.2 parts of accelerator, 0.1-0.2 parts of defoamer;

[0008] The complex amine agent is prepared by mixing N-methyldiethanolamine, a triazine ring structure, a secondary alcohol amine and a primary alcohol amine in a mass ratio of 6 to 10:2 to 3:1:1.

[0009] Furthermore, the triazine ring structure is prepared by the following steps:

[0010] A 37% formaldehyde aqueous solution and a sterically hindered amine are added to an organic solvent with stirring. After the addition is completed, the temperature is raised to 75-80° C. with stirring, and the reaction is carried out under constant temperature stirring for 5-6 hours. After the reaction is completed, the organic solvent is removed by rotary evaporation, and then the triazine ring structure is obtained after purification and separation by chromatography and drying.

[0011] Furthermore, the usage ratio of the organic solvent, 37% formaldehyde aqueous solution and aminobenzene derivative is 100 mL: 8.2-8.5 g: 0.1 mol.

[0012] Furthermore, the organic solvent is one of tetrahydrofuran, N,N-dimethylformamide and dimethyl sulfoxide.

[0013] Furthermore, the sterically hindered amine is one of 2-amino-2-methyl-1-propanol, 2-amino-2-methyl-1-butanol, and 2-amino-2-methyl-1-pentanol.

[0014] Furthermore, the sterically hindered amine is 2-amino-2-methyl-1-butanol, and the process of preparing the triazine ring structure from 2-amino-2-methyl-1-butanol is as follows:

[0015]

[0016] Furthermore, the primary alcoholamine is one of monoethanolamine and diglycolamine.

[0017] Furthermore, the secondary alcohol amine is one of diethanolamine, butylethanolamine and diisopropanolamine.

[0018] Furthermore, the emulsifier is one of emulsifier E-1312, emulsifier E-1320 and emulsifier E-1340.

[0019] Furthermore, the corrosion inhibitor is prepared by mixing ethylenediaminetetramethylenephosphonic acid and polyvinylpyrrolidone in a mass ratio of 2:1 to 2.

[0020] Furthermore, the accelerator is one of homopiperazine, 1-methylpiperazine and 2-methylpiperazine.

[0021] Furthermore, the defoamer is BYK-022 defoamer.

[0022] Furthermore, a method for preparing a highly efficient composite desulfurization and decarbonization solvent comprises the following steps:

[0023] Weigh each component according to the above weight portion, mix and stir the complex amine agent and emulsifier for 30 to 40 minutes, then add the corrosion inhibitor, accelerator and defoamer into the mixture with stirring, and then mix and stir for 5 to 10 minutes to obtain a high-efficiency composite desulfurization and decarbonization solvent.

[0024] Beneficial effects of the present invention:

[0025] The present invention provides a highly efficient composite desulfurization and decarbonization solvent. The desulfurization and decarbonization solvent prepared by the present invention is used in a natural gas desulfurization and decarbonization treatment process. After testing, H 2 S removal rate ≥99.98%; CO 2 Removal rate ≥ 66.85%; total removal rate of organic sulfides ≥ 94.80%.

[0026] The main agent of the desulfurization and decarbonization solvent of the present invention is a composite amine agent, which is also compounded with an emulsifier and a accelerator, wherein the composite amine agent is a mixture of N-methyldiethanolamine, a triazine ring structure, a secondary alcohol amine and a primary alcohol amine. The composite liquid of the secondary alcohol amine and the primary alcohol amine in the composite amine agent has the effect of removing H 2 S and CO 2 ability, but with H 2 S and CO 2 As the content decreases, the removal efficiency gradually decreases, and side reactions are prone to occur, so the dosage should not be too large. In order to ensure the comprehensive effect of the complex amine agent, the present invention uses N-methyldiethanolamine as the main agent and adds the triazine ring structure prepared by the present invention. Among them, N-methyldiethanolamine has good chemical stability and is not easy to degrade, so it serves as the main agent, but its alkalinity is weak and the reaction speed is slow. Therefore, it is compounded with the composite liquid of secondary alcohol amine and primary alcohol amine to achieve fast and slow matching, which helps to improve the removal rate while ensuring the removal effect. At the same time, the present invention activates N-methyldiethanolamine by adding a promoter (high piperazine, 1-methyl piperazine, 2-methyl piperazine) to increase the CO of N-methyldiethanolamine. 2 removal capacity, and improve its resistance to low-content CO 2 At the same time, the triazine ring structure prepared by the present invention has a triazine structure, which is effective for H 2S has excellent selective absorption effect, but the isotriazine structure is easy to degrade. The present invention adds emulsifiers with isomeric tridecanol structure (emulsifier E-1312, emulsifier E-1320 and emulsifier E-1340) to ensure the H of the configured desulfurization and decarbonization solvent. 2 The triazine ring structure can theoretically absorb H by a 1:3 molar ratio. 2 S, a nucleophilic substitution reaction occurs during the absorption process, and the sterically hindered amine (one of 2-amino-2-methyl-1-propanol, 2-amino-2-methyl-1-butanol, and 2-amino-2-methyl-1-pentanol) is gradually released. The sterically hindered amine of the present invention has excellent CO 2 Moreover, since the carbon atoms adjacent to the nitrogen atom of the sterically hindered amine are connected to two large alkyl groups, the alkyl groups have a strong steric hindrance effect, which can ensure its stable existence in the desulfurization and decarbonization solvent.

[0027] The present invention configures the above-mentioned desulfurization and decarbonization solvent based on the principle of complementary advantages and reduction in efficiency. Studies have shown that the desulfurization and decarbonization solvent of the present invention has efficient and significant desulfurization and decarbonization effects and has multiple synergistic effects, and has significant market prospects and promotion value. DETAILED DESCRIPTION

[0028] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0029] Example 1

[0030] Preparation of triazine ring structures:

[0031] A 37% aqueous formaldehyde solution and 2-amino-2-methyl-1-propanol are added to an organic solvent, tetrahydrofuran, with stirring, wherein the amount ratio of the organic solvent, the 37% aqueous formaldehyde solution and the 2-amino-2-methyl-1-propanol is 100 mL:8.2 g:0.1 mol. After the addition is completed, the temperature is raised to 75° C. with stirring, and the reaction is carried out with constant stirring for 5 hours. After the reaction is completed, the organic solvent is removed by rotary evaporation, and then the triazine ring structure is obtained after purification, separation and drying by chromatography.

[0032] Example 2

[0033] Preparation of triazine ring structures:

[0034] A 37% aqueous formaldehyde solution and 2-amino-2-methyl-1-butanol are added to an organic solvent N,N-dimethylformamide with stirring, wherein the amount ratio of the organic solvent, the 37% aqueous formaldehyde solution and the 2-amino-2-methyl-1-butanol is 100 mL:8.4 g:0.1 mol. After the addition is completed, the temperature is raised to 80° C. with stirring, and the reaction is stirred at a constant temperature for 6 hours. After the reaction is completed, the organic solvent is removed by rotary evaporation, and then the triazine ring structure is obtained after purification and separation by chromatography and drying.

[0035] Example 3

[0036] Preparation of triazine ring structures:

[0037] A 37% aqueous formaldehyde solution and 2-amino-2-methyl-1-pentanol are added to an organic solvent, dimethyl sulfoxide, with stirring, wherein the amount ratio of the organic solvent, the 37% aqueous formaldehyde solution and the 2-amino-2-methyl-1-pentanol is 100 mL:8.5 g:0.1 mol. After the addition is completed, the temperature is raised to 80° C. with stirring, and the reaction is carried out with constant stirring for 6 hours. After the reaction is completed, the organic solvent is removed by rotary evaporation, and then the triazine ring structure is obtained after purification, separation and drying by chromatography.

[0038] Example 4

[0039] Preparation of highly efficient compound desulfurization and decarbonization solvents:

[0040] First, a highly efficient compound desulfurization and decarbonization solvent is prepared, including the following components in parts by weight:

[0041] 75 parts of complex amine, 22 parts of emulsifier E-131, 0.2 parts of corrosion inhibitor, 0.1 parts of homopiperazine, 0.1 parts of BYK-022 defoamer;

[0042] Wherein, the composite amine agent is prepared by mixing N-methyldiethanolamine, the triazine ring structure prepared in Example 1, monoethanolamine and diethanolamine in a mass ratio of 6:2:1:1; wherein, the emulsifier E-131 is purchased from Hai'an Petrochemical Plant in Jiangsu Province; wherein, the corrosion inhibitor is prepared by mixing ethylenediaminetetramethylenephosphonic acid and polyvinylpyrrolidone in a mass ratio of 2:1;

[0043] Then, the preparation method of the highly efficient composite desulfurization and decarbonization solvent comprises the following steps:

[0044] Weigh each component according to the above weight portion, mix and stir the complex amine agent and emulsifier E-1312 for 30 minutes, then add the corrosion inhibitor, homopiperazine and BYK-022 defoamer into the mixture, and then mix and stir for 5 minutes to obtain a high-efficiency composite desulfurization and decarbonization solvent.

[0045] Example 5

[0046] Preparation of highly efficient compound desulfurization and decarbonization solvents:

[0047] First, a highly efficient compound desulfurization and decarbonization solvent is prepared, including the following components in parts by weight:

[0048] 78 parts of complex amine, 8 parts of emulsifier E-1320, 0.5 parts of corrosion inhibitor, 0.2 parts of 1-methylpiperazine, 0.2 parts of BYK-022 defoamer;

[0049] Wherein, the composite amine agent is mixed by N-methyldiethanolamine, the triazine ring structure prepared in Example 2, diglycolamine and butylethanolamine in a mass ratio of 8:3:1:1; wherein, the emulsifier E-1320 is purchased from Hai'an Petrochemical Plant in Jiangsu Province; wherein, the corrosion inhibitor is mixed by ethylenediaminetetramethylenephosphonic acid and polyvinylpyrrolidone in a mass ratio of 1:1;

[0050] Then, the preparation method of the highly efficient composite desulfurization and decarbonization solvent comprises the following steps:

[0051] Weigh each component according to the above weight portion, mix the complex amine agent and emulsifier E-1320 and stir for 40 minutes, then add the corrosion inhibitor, 1-methylpiperazine and BYK-022 defoamer and stir for another 10 minutes to obtain a high-efficiency composite desulfurization and decarbonization solvent.

[0052] Example 6

[0053] Preparation of highly efficient compound desulfurization and decarbonization solvents:

[0054] First, a highly efficient compound desulfurization and decarbonization solvent is prepared, including the following components in parts by weight:

[0055] 80 parts of complex amine, 10 parts of emulsifier E-1340, 0.5 parts of corrosion inhibitor, 0.2 parts of 2-methylpiperazine, 0.2 parts of BYK-022 defoamer;

[0056] Wherein, the composite amine agent is mixed by N-methyldiethanolamine, the triazine ring structure prepared in Example 3, diglycolamine and diisopropanolamine in a mass ratio of 10:3:1:1; wherein, the emulsifier E-1340 is purchased from Hai'an Petrochemical Plant in Jiangsu Province; wherein, the corrosion inhibitor is mixed by ethylenediaminetetramethylenephosphonic acid and polyvinylpyrrolidone in a mass ratio of 1:1;

[0057] Then, the preparation method of the highly efficient composite desulfurization and decarbonization solvent comprises the following steps:

[0058] Weigh each component according to the above weight portion, mix and stir the complex amine agent and emulsifier E-1340 for 40 minutes, then add the corrosion inhibitor, 2-methylpiperazine and BYK-022 defoamer into the mixture, and then mix and stir for 10 minutes to obtain a high-efficiency composite desulfurization and decarbonization solvent.

[0059] Comparative Example 1

[0060] Comparative Example 1 is the control group of Example 5, in which the emulsifier E-1320 in Example 5 is removed, and the other raw materials, raw material ratios and preparation methods remain unchanged, and finally a high-efficiency composite desulfurization and decarbonization solvent is obtained.

[0061] Comparative Example 2

[0062] Comparative Example 2 is the control group of Example 5, in which the promoter 1-methylpiperazine in Example 5 is removed, and the other raw materials, raw material ratios and preparation methods remain unchanged, and finally a high-efficiency composite desulfurization and decarbonization solvent is obtained.

[0063] Comparative Example 3

[0064] Comparative Example 3 is the control group of Example 5, in which the triazine ring structure prepared in Example 2 in Example 5 is removed, and the other raw materials, raw material ratios and preparation methods remain unchanged, and finally a high-efficiency composite desulfurization and decarbonization solvent is obtained.

[0065] Test Example 1

[0066] The high-efficiency composite desulfurization and decarbonization solvents prepared in Examples 4 to 6 and Comparative Examples 1 to 3 were used to desulfurize and decarbonize natural gas raw gas. The volume percentage composition of the natural gas raw gas is as follows. The natural gas raw gas is subjected to desulfurization and decarbonization treatment to obtain purified gas. The components of the purified gas are detected by gas chromatography. Each group of Examples / Comparative Examples is tested three times and the average value is taken. The test results finally calculated are recorded in Table 1 below. At the same time, H 2 S removal rate, CO 2 The removal rate and the total removal rate of organic sulfides (carbonyl sulfide + mercaptan) are recorded in the following table 1:

[0067] Raw gas composition (by volume percentage): low carbon hydrocarbons 85.72%, H 2 S5.21%, CO 2 7.36%, carbonyl sulfide 125ppm, mercaptan 548ppm.

[0068] Table 1 Test results

[0069]

[0070] As can be seen from Table 1, the high-efficiency composite desulfurization and decarbonization solvents prepared in Examples 4 to 6 of the present invention are effective for H 2 S, CO 2 It has excellent removal effect on organic sulfides.

[0071] It should be noted that, in this article, terms such as "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or equipment that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or equipment.

[0072] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A highly efficient composite desulfurization and decarbonization solvent, characterized in that: It includes the following components by weight: 75-80 parts of complex amine, 2-10 parts of emulsifier, 0.2-0.5 parts of corrosion inhibitor, 0.1-0.2 parts of accelerator, 0.1-0.2 parts of defoamer; The complex amine agent is prepared by mixing N-methyldiethanolamine, a triazine ring structure, a secondary alcohol amine and a primary alcohol amine in a mass ratio of 6 to 10:2 to 3:1:1; The triazine ring structure is prepared by the following steps: Add 37% formaldehyde aqueous solution and sterically hindered amine to an organic solvent with stirring, and after the addition is completed, stir and heat to 75-80° C., and react with constant temperature stirring for 5-6 hours. After the reaction is completed, remove the organic solvent by rotary evaporation, and then purify and separate by chromatography and dry to obtain a triazine ring structure; the amount ratio of the organic solvent, 37% formaldehyde aqueous solution and sterically hindered amine is 100 mL: 8.2-8.5 g: 0.1 mol; The sterically hindered amine is one of 2-amino-2-methyl-1-propanol, 2-amino-2-methyl-1-butanol, and 2-amino-2-methyl-1-pentanol; The emulsifier is one of emulsifier E-1312, emulsifier E-1320 and emulsifier E-1340; The accelerator is one of homopiperazine, 1-methylpiperazine and 2-methylpiperazine.

2. A highly efficient composite desulfurization and decarbonization solvent according to claim 1, characterized in that: The organic solvent is one of tetrahydrofuran, N,N-dimethylformamide and dimethyl sulfoxide.

3. The highly efficient composite desulfurization and decarbonization solvent according to claim 1, characterized in that: The primary alcoholamine is one of monoethanolamine and diglycolamine; the secondary alcoholamine is one of diethanolamine, butylethanolamine and diisopropanolamine.

4. The highly efficient composite desulfurization and decarbonization solvent according to claim 1, characterized in that: The corrosion inhibitor is prepared by mixing ethylenediaminetetramethylenephosphonic acid and polyvinylpyrrolidone in a mass ratio of 2:1-2.

5. The high-efficiency composite desulfurization and decarbonization solvent according to claim 1, characterized in that: The defoamer is BYK-022 defoamer.

6. A method for preparing a highly efficient composite desulfurization and decarbonization solvent according to any one of claims 1 to 5, characterized in that: The following steps are involved: Weigh each component according to the above weight portion, mix and stir the complex amine agent and emulsifier for 30 to 40 minutes, then add the corrosion inhibitor, accelerator and defoamer into the mixture with stirring, and then mix and stir for 5 to 10 minutes to obtain a high-efficiency composite desulfurization and decarbonization solvent.

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