A highly selective amine absorbent and its preparation method

Abstract

The present invention relates to a highly selective amine-based absorbent and its preparation method, belonging to the technical field of industrial desulfurization. The absorbent of the present invention comprises a primary absorbent, an organic sulfur removal accelerator, an auxiliary agent, and deionized water. The primary absorbent comprises an alcoholamine containing a tertiary amine structure and / or containing steric hindrance. The alcoholamine containing a tertiary amine structure and / or containing steric hindrance comprises one or more of methyldiethanolamine, diisopropanolamine, 2-(tert-butylamino)ethanol, tert-butylaminoethoxyethanol, and 2-amino-2-methyl-1-propanol. The present invention uses sterically hindered amines to inhibit CO2 absorption, reducing regeneration energy consumption by 40%, thereby addressing the technical problems of high CO2 co-absorption rates and high regeneration energy consumption in the prior art.

Description

Technical Field

[0001] The present invention relates to the technical field of industrial desulfurization, in particular to a high-selectivity amine absorbent and a preparation method thereof. Background Art

[0002] In the field of industrial waste gas desulfurization, especially in the treatment of steel, coal chemical industry, and biogas, the efficient removal of hydrogen sulfide (H2S) and organic sulfur (such as COS and CS2) is a core requirement. At the same time, it is necessary to take into account the selective absorption and control of carbon dioxide (CO2) to reduce regeneration energy consumption. Traditional desulfurization technologies include amine methods (such as MDEA and DEA), catalytic oxidation wet methods, dry methods (iron oxide), and hydrolysis to remove organic sulfur. Although these processes are widely used, they have the following problems:

[0003] ① Conventional amine absorbents (such as CN 119075601 A) have limited selectivity for hydrogen sulfide, which easily leads to co-absorption of CO2, resulting in a 30% to 50% increase in regeneration energy consumption; the traditional amine method has a removal rate of less than 60% for organic sulfur such as COS and CS2, and requires additional hydrolysis or catalytic equipment, increasing costs and process complexity; the system stability is insufficient: the amine solution is easily oxidized and degraded, and impurities such as tar and naphthalene can easily cause equipment corrosion and foam accumulation, shortening the life of the amine solution.

[0004] ② Although the catalytic oxidation wet method (such as CN 118421382 A) can selectively remove H2S, the residual organic sulfur content is high (COS ≥ 60 ppm), and the amount of secondary salts generated is large, and the treatment cost is high.

[0005] ③ Dry method (iron oxide) (such as CN119530307A) simplifies the process flow and reduces equipment investment, but it can only remove H2S, has low organic sulfur treatment capacity, and the adsorbent needs to be replaced frequently.

[0006] ④ The organic sulfur conversion rate of the hydrolysis desulfurization method (such as CN119565590A) is ≥95%, but it needs to be combined with a subsequent desulfurization step, and there are problems such as harsh reaction conditions and high energy consumption.

[0007] Existing technologies have significant limitations in highly selective desulfurization (especially CO2 / S separation), organic sulfur removal, long-term system stability, and economic efficiency. The core of this invention is to address these challenges through optimized amine formulation and process synergy, achieving highly efficient sulfide removal while reducing energy consumption and operating and maintenance costs. Summary of the Invention

[0008] In order to solve the defects of the existing amine desulfurization technology in the art, such as low organic sulfur removal efficiency, high CO2 co-absorption rate, severe equipment corrosion, complex process flow, and insufficient adaptability to multiple scenarios, the present invention provides a highly selective amine absorbent and its preparation method, as well as its application in industrial waste gas desulfurization.

[0009] The first object of the present invention is to provide a highly selective amine absorbent, comprising a main absorbent, an organic sulfur removal accelerator, an auxiliary agent and deionized water; the main absorbent comprises an alcoholamine containing a tertiary amine structure and / or a sterically hindered structure;

[0010] The alcoholamine containing a tertiary amine structure and / or a sterically hindered structure includes one or more of methyldiethanolamine (MDEA), diisopropanolamine, 2-(tert-butylamino)ethanol (TBEA), tert-butylaminoethoxyethanol (TBEE) and 2-amino-2-methyl-1-propanol (AMP);

[0011] In some embodiments of the present invention, methyldiethanolamine MDEA accounts for 10-30wt%, and exemplarily, it can be 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30wt%, and further preferably 15wt%; 2-(tert-butylamino)ethanol TBEA accounts for 0-10wt%, and exemplarily, it can be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10wt%, and further preferably 2wt%; tert-butylaminoethoxyethanol TBEE accounts for 0-10wt%; 2-amino-2-methyl-1-propanol AMP accounts for 0-15wt%, and exemplarily, it can be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10wt%, and further preferably 3wt%.

[0012] In some embodiments of the present invention, the main absorbent accounts for 15-40wt%, exemplarily, it can be 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 40wt%, further preferably 20wt%; the organic sulfur removal promoter accounts for 5-25wt%, exemplarily, it can be 5, 10, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30wt%, further preferably 20wt%; the auxiliary agent accounts for 1-10wt%, exemplarily, it can be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10wt%, further preferably 2wt%; deionized water accounts for 20-70wt%, further preferably 58wt%.

[0013] In some embodiments of the present invention, the organic sulfur removal accelerator includes two or more of (1H-pyrrol-3-yl)methylamine, 3-methylpyrrolidine, 1,3-bis(methylamino)-2-propanol, and N-methyltetrahydro-2H-thiopyran-4-amine. Preferably, the accelerator includes (1H-pyrrol-3-yl)methylamine and 1,3-bis(methylamino)-2-propanol, (1H-pyrrol-3-yl)methylamine and N-methyltetrahydro-2H-thiopyran-4-amine, and 1,3-bis(methylamino)-2-propanol and N-methyltetrahydro-2H-thiopyran-4-amine. The present invention achieves a COS / CS2 removal rate of ≥95% through catalytic hydrolysis of pyrrole or thiopyran, eliminating the need for a hydrolysis unit and solving the technical problem of low organic sulfur removal rates in the prior art, which requires additional hydrolysis equipment.

[0014] In some embodiments of the present invention, the adjuvants include preservatives, antioxidants and defoaming agents.

[0015] In some embodiments of the present invention, the preservative includes benzotriazole or imidazoline derivatives, and the content of the preservative is 0.5wt%~2wt%, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.2, 1.5, 2.0wt%; the present invention can form a dense protective film on the surface of the equipment through the use of the preservative.

[0016] The antioxidant includes hydroquinone or butylated hydroxyanisole compounds; the content of the antioxidant is 0.1wt%~1wt%, illustratively, it can be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1wt% and the like; the present invention can effectively prevent the degradation of amine solution and extend the service life by using the antioxidant.

[0017] The defoaming agent includes a polysiloxane or polyether compound, and the content of the defoaming agent is 0.1wt% to 0.5wt%. The present invention can quickly eliminate foam by using the defoaming agent to ensure stable operation of the system.

[0018] In the present invention, the components work synergistically to reduce energy consumption and achieve long-term stable operation. Deionized water is used to make up to 100% to ensure uniform distribution of the absorbent and improve absorption efficiency.

[0019] The second object of the present invention is to provide a method for preparing the highly selective amine absorbent, comprising the following steps:

[0020] A compound having a tertiary amine structure and an alcoholamine having a steric hindrance effect are mixed, added to a reactor, and heated and stirred; an organic sulfur removal accelerator is added, and the mixture is heated and stirred to obtain a main absorbent mixed solution;

[0021] dissolving the auxiliary agent in a solvent and heating to dissolve the auxiliary agent to obtain an auxiliary agent solution;

[0022] The auxiliary agent solution is added to the main absorbent mixed solution, the temperature is controlled to be ≤50°C, and the mixture is stirred evenly at a speed of 500-600 rpm to obtain the highly selective amine absorbent.

[0023] In some embodiments of the present invention, the heating and stirring temperature is 40-50° C., the time is 20-40 min, and the stirring speed is 200-300 rpm;

[0024] The heating temperature is 40~80℃ and the time is 0.5~2 hours;

[0025] The temperature for heating and dissolving is 30~60℃.

[0026] In the present invention, the tertiary amine structure (without H on N) has a weak alkalinity (pKa≈8.5) and preferentially undergoes protonation reaction with H2S (H2S+R3N→R3NH+·HS - ), while the absorption rate of CO2 is significantly lower than that of H2S (selectivity coefficient ≥ 10). At the same time, the amino group of sterically hindered amines (such as AMP) is surrounded by bulky substituents to inhibit the carbamate reaction of CO2 (2RNH2+CO2→RNHCOO - +RNH3 + ), reducing CO2 co-absorption (CO2 absorption capacity reduced by 30%-50%), but has a high affinity for small molecules of H2S, forming stable thiolate (R3NH + ·HS - ).

[0027] In this invention, organic sulfur removal (such as COS and CS2) is primarily achieved through the synergistic combination of catalytic hydrolysis and chemical absorption. The electron-rich nitrogen atoms of the pyrroles on the organic sulfur removal accelerator act as nucleophilic sites, attacking the sulfur atoms in COS / CS2, weakening the sulfur-carbon bond and promoting the hydrolysis reaction. The hydrolysis rate is increased by 3-5 times compared to the absence of a catalyst. Alternatively, the sulfur atoms of the thiopyran form sulfur-sulfur bonds with organic sulfur molecules, reducing the hydrolysis activation energy and accelerating the decomposition into H2S and CO2. Simultaneously, the amino groups of the thiopyran form hydrogen-bonding networks with water molecules, accelerating proton transfer and enabling chemical absorption. Under the catalysis of the organic sulfur removal accelerator, COS reacts with water to produce H2S and CO2, while CS2 hydrolyzes stepwise, ultimately also producing H2S and CO2. The amino groups in 1,3-bis(methylamino)-2-propanol form hydrogen-bonding networks with water molecules, accelerating proton transfer and increasing the absorption rate of the hydrolysis products, H2S and CO2. This reduces the H2S and CO2 concentrations in the absorbent, thereby increasing the forward rate of the hydrolysis reaction and achieving chemical absorption.

[0028] In the present invention, the cooperative hydrolysis pathway is as follows:

[0029] Step 1: COS combines with the promoter to form a transition state complex (COS + promoter → [promoter-S-CO]);

[0030] Step 2: Water molecules attack the carbonyl carbon in the complex to generate H2S and CO2 ([promoter-S-CO] + H2O → H2S + CO2 + promoter);

[0031] The H2S generated by hydrolysis is quickly captured by the primary absorbent (H2S + R3N → R3NH + HS - ), and finally enriched in the liquid phase in the form of sulfide, achieving indirect removal of organic sulfur (total removal rate ≥ 95%).

[0032] The above technical solution of the present invention has the following advantages over the prior art:

[0033] 1. This invention uses sterically hindered amines to inhibit CO2 absorption, reducing regeneration energy consumption by 40%, thereby resolving the technical problems of high CO2 co-absorption rates and high regeneration energy consumption in the prior art. The desulfurization absorbent of this invention is effective for absorbing H2S, COS, and CS2, but has a very low CO2 co-absorption rate, thus demonstrating high selectivity.

[0034] 2. The present invention achieves a COS / CS2 removal rate of ≥95% through pyrrole / thiopyran catalytic hydrolysis, eliminating the hydrolysis unit and solving the technical problem of low organic sulfur removal rate and the need for additional hydrolysis equipment in the prior art.

[0035] 3. The present invention can ensure the life of the amine solution ≥ 12 months and the corrosion rate ≤ 0.03 mm / year through the synergistic protection of preservatives and antioxidants, thereby solving the technical problems of the prior art that the amine solution is easily oxidized and degraded and the equipment is severely corroded.

[0036] 4. The present invention has wide adaptability to multiple scenarios and does not require the establishment of multiple desulfurization solutions, such as in the fields of steel, coal chemical industry, biogas, etc. DETAILED DESCRIPTION

[0037] The present invention will be further described below with reference to specific examples so that those skilled in the art can better understand the present invention and implement it, but the examples are not intended to limit the present invention.

[0038] The desulfurization reaction device used in the present invention is a conventional desulfurization device in the field and has not been improved. It mainly includes an alkali washing tower; an alkali liquid circulation pump; a desulfurization tower; a rich liquid circulation pump; an amine liquid cooler; a lean and rich liquid heat exchanger; a regeneration tower; a reboiler; an acid gas cooler; a reflux pump; a lean liquid circulation pump; a lean liquid cooler; an oxidation reaction tower; a solution circulation pump; a sulfur separation unit; a fan; a sulfur-rich material pump; a molten sulfur kettle; and an alkali liquid storage tank.

[0039] Example 1 (Blast furnace gas desulfurization)

[0040] This embodiment provides a highly selective amine absorbent and its application in industrial waste gas desulfurization, as shown below:

[0041] 1. The preparation process of amine absorbent includes the following steps:

[0042] 1. Add 25 wt% MDEA, 5 wt% TBEA, and 5 wt% AMP to a reactor and stir at 50°C and 300 rpm for 30 minutes. Add 12 wt% (1H-pyrrol-3-yl)methylamine and 3 wt% N-methyltetrahydro-2H-thiopyran-4-amine, raise the temperature to 60°C, and stir at this constant temperature for 1 hour to obtain a primary absorbent mixed solution.

[0043] 2. Dissolve 1.5 wt% of benzotriazole and 0.8 wt% of hydroquinone in 5 wt% of deionized water, heat to 50°C until completely dissolved to obtain a first additive solution; mix 0.2 wt% of a polysiloxane defoamer with 43.5 wt% of deionized water to obtain a second additive solution, and ultrasonically disperse for 10 minutes.

[0044] 3. Slowly add the auxiliary agent solution and defoamer solution obtained in step 2 to the main absorbent mixture obtained in step 1, controlling the temperature to ≤50°C; stir at 500 rpm for 30 minutes until the system is uniform and there is no stratification.

[0045] 2. Application conditions: Blast furnace gas is introduced into the desulfurization tower from the bottom of the desulfurization tower. The H2S content in the blast furnace gas is 36 mg / m 3 , COS is 145 mg / m 3 , CO2 content was 21wt%. The desulfurization tower had a gas-liquid volume ratio of 250, an absorption temperature of 40°C, a pressure of 7 kPa(G), and a regeneration temperature of 118°C. H2S / COS concentrations were determined by gas chromatography (GB / T 11060); CO2 concentration was determined by non-dispersive infrared absorption (HJ 870-2017); and corrosion rates were determined by weight loss (GBT39534-2020).

[0046] Comparative Example 1

[0047] Traditional iron oxide dry desulfurization method:

[0048] Granular iron oxide desulfurizer (Fe2O3·H2O content ≥90%, particle size 3-5 mm) is filled into the fixed bed desulfurization tower with a packing density of 0.8 g / cm 3, forming a desulfurization agent layer. Nitrogen is introduced into the desulfurization tower to replace the air, and the nitrogen flow rate is controlled to be twice the volume of the tower for 30 minutes. Then, a nitrogen mixture containing 5% water vapor (v / v) is introduced, and the temperature is maintained at 40°C to activate the desulfurizer for 2 hours. Blast furnace gas is introduced from the bottom of the desulfurization tower, and the gas composition is the same as in the embodiment. The control operating parameters are as follows: space velocity: 800 h -1 (gas volume flow rate / desulfurizer volume), operating temperature: 40°C, system pressure: near atmospheric pressure (0 kPa(G)), gas humidity: maintain the relative humidity of the inlet gas at 60%. The detection method is the same as in the embodiment.

[0049] The comparison results of the desulfurization effect of the absorbent in this embodiment on blast furnace gas and the traditional dry desulfurization are shown in Table 1.

[0050] Table 1

[0051]

[0052] Example 2 (Desulfurization of Coke Oven Gas)

[0053] This embodiment provides a highly selective amine absorbent and its application in industrial waste gas desulfurization, as shown below:

[0054] 1. The absorbent preparation process includes the following steps:

[0055] 1. Add 30 wt% MDEA and 8 wt% TBEE to a reactor and stir at 50°C and 300 rpm for 30 minutes. Add 8 wt% 3-methylpyrrolidine and 5 wt% 1,3-bis(methylamino)-2-propanol, raise the temperature to 60°C, and stir at this constant temperature for 1 hour to obtain a primary absorbent mixture.

[0056] 2. Dissolve 2 wt% of an imidazoline derivative and 1% of butylated hydroxyanisole in 5% deionized water, heat to 50°C until completely dissolved, and obtain a first additive solution; mix 0.2% of a polysiloxane defoamer with 41% of deionized water, and ultrasonically disperse for 10 minutes to obtain a second additive solution.

[0057] 3. Slowly add the first auxiliary agent solution and the second auxiliary agent solution obtained in step 2 to the main absorbent mixed solution obtained in step 1, controlling the temperature to ≤50°C; stir at 500 rpm for 30 minutes until the system is uniform and there is no stratification.

[0058] 2. Application conditions: The coke oven gas is introduced into the absorption tower from the bottom of the absorption tower. The H2S content in the coke oven gas is 5000mg / m 3 , COS is 800 mg / m 3 , CS2 is 400mg / m 3 , CO2 3.5%, tar 80 mg / m3 The absorption tower has a gas-to-liquid volume ratio of 200, an absorption temperature of 38°C, a pressure of 5 kPa(G), and a regeneration temperature of 120°C. H2S / COS / CS2 concentrations were determined by gas chromatography (GB / T 11060); CO2 concentration was determined by non-dispersive infrared absorption (HJ 870-2017); and corrosion rate was determined by weight loss (GBT39534-2020).

[0059] Comparative Example 2

[0060] This comparative example provides a traditional wet catalytic oxidation desulfurization method, which includes the following specific steps:

[0061] A 15wt% sodium carbonate solution was added to the reactor as the absorption matrix, followed by 0.5wt% cobalt phthalocyanine catalyst and 0.2wt% ethylenediaminetetraacetic acid stabilizer. The temperature was controlled at 40±2°C and stirred at 200rpm for 45 minutes until the system was homogeneous. Finally, deionized water was added to the total mass of 100%. The coke oven gas treatment parameters remained the same as in the embodiment. The absorption tower had a gas-liquid volume ratio of 200, an operating temperature of 38°C, and a pressure of 5kPa(G). The detection method used the same standard system as in the embodiment.

[0062] The comparison results of the desulfurization effect of the absorbent obtained in this example on coke oven gas and the traditional wet catalytic oxidation desulfurization are shown in Table 2.

[0063] Table 2

[0064]

[0065] Example 3 (Desulfurization of Coal Chemical Tail Gas)

[0066] This embodiment provides a highly selective amine absorbent and its application in industrial waste gas desulfurization, as shown below:

[0067] 1. The absorbent preparation process includes the following steps:

[0068] 1. Add 20 wt% MDEA and 10 wt% AMP to a reactor and stir at 50°C and 300 rpm for 30 minutes. Add 15 wt% (1H-pyrrol-3-yl)methylamine and 5 wt% N-methyltetrahydro-2H-thiopyran-4-amine, raise the temperature to 60°C, and stir at this temperature for 1 hour to obtain a main absorbent mixed solution.

[0069] 2. Dissolve 2 wt% of benzotriazole and 1 wt% of butylated hydroxyanisole in 5 wt% of deionized water, heat to 50°C until completely dissolved, and obtain a first additive solution; mix 0.5 wt% of a polyether defoamer with 41.5 wt% of deionized water, and ultrasonically disperse for 10 minutes to obtain a second additive solution.

[0070] 3. Slowly add the first auxiliary agent solution and the second auxiliary agent solution obtained in step 2 to the main absorbent mixed solution obtained in step 1, controlling the temperature to ≤50°C; stir at 500 rpm for 30 minutes until the system is uniform and there is no stratification.

[0071] 2. Application conditions: The crude synthesis gas from coal chemical industry is introduced into the absorption tower from the bottom of the absorption tower. The H2S content in the crude synthesis gas is 8000mg / m 3 , COS is 2000mg / m 3 , CS2 is 600mg / m 3 , CO2 is 8%. The absorption tower has a gas-liquid volume ratio of 150, an absorption temperature of 42°C, a pressure of 20 kPa(G), and a regeneration temperature of 123°C. H2S / COS / CS2 concentrations are determined by gas chromatography (GB / T11060); CO2 concentration is determined by non-dispersive infrared absorption (HJ 870-2017); and corrosion rate is determined by weight loss (GBT39534-2020).

[0072] Comparative Example 3

[0073] This comparative example provides a traditional physical adsorption method for desulfurization, which is as follows:

[0074] Select a specific surface area of ​​800-1000 m 2 / g columnar activated carbon (particle size 3-5 mm) was placed in an oven and dried at 120°C for 4 hours to remove moisture. The dried activated carbon was filled into a fixed bed adsorption tower. Coal chemical crude synthesis gas was introduced from the bottom of the adsorption tower, and the gas composition was consistent with that in Example 3. The adsorption temperature was controlled at 42°C, the pressure was 20 kPa (G), and the gas space velocity was 300h -1 The detection method is the same as that in Example 3.

[0075] The comparison results of the desulfurization effect of the absorbent obtained in this example on the crude synthesis gas from coal chemical industry and the desulfurization by traditional physical adsorption method are shown in Table 3.

[0076] Table 3

[0077]

[0078] Example 4 (Biomass Gas Purification)

[0079] This embodiment provides a highly selective amine absorbent and its application in industrial waste gas desulfurization, as shown below:

[0080] 1. Absorbent preparation process:

[0081] 1. Add 15 wt% MDEA, 2 wt% TBEA, and 3 wt% AMP to a reactor and stir at 50°C and 300 rpm for 30 minutes. Add 8 wt% 1,3-bis(methylamino)-2-propanol and 5 wt% 3-methylpyrrolidine, raise the temperature to 60°C, and stir at this constant temperature for 1 hour to obtain a primary absorbent mixture.

[0082] 2. Dissolve 1 wt% of benzotriazole and 1 wt% of butylated hydroxyanisole in 5 wt% of deionized water, heat to 50°C until completely dissolved, and obtain a first additive solution; mix 0.3 wt% of a polysiloxane defoamer with 65.7% of deionized water, and ultrasonically disperse for 10 minutes to obtain a second additive solution.

[0083] 3. Slowly add the first auxiliary agent solution and the second auxiliary agent solution obtained in step 2 to the main absorbent mixed solution obtained in step 1, controlling the temperature to ≤50°C; stir at 500 rpm for 30 minutes until the system is uniform and there is no stratification.

[0084] 2. Application conditions: The biogas is introduced into the absorption tower from the bottom of the absorption tower. The H2S content in the biogas is 3000mg / m 3 , COS is 800 mg / m 3 , CO2 is 35%. The absorption tower has a gas-liquid volume ratio of 200, an absorption temperature of 40°C, a pressure of 3 kPa(G), and a regeneration temperature of 115°C. H2S / COS concentrations are measured using gas chromatography (GB / T 11060); CO2 concentration is measured using the non-dispersive infrared absorption method (HJ 870-2017); and corrosion rates are measured using the weight loss method (GBT39534-2020).

[0085] Comparative Example 4

[0086] 25wt% MDEA and 75wt% deionized water were added to a reactor and stirred at 40°C and 200 rpm for 40 minutes to obtain a homogeneous absorption liquid. 0.5wt% polysiloxane defoamer was added, the temperature was raised to 50°C, and the mixture was stirred at 400 rpm for 20 minutes to complete the preparation. Coal chemical crude synthesis gas was introduced from the bottom of the absorption tower, with the gas composition consistent with that in Example 4. The absorption tower had a gas-to-liquid volume ratio of 180, an absorption temperature of 45°C, atmospheric pressure, and a regeneration temperature of 125°C. The detection method used the same standards as in Example 4.

[0087] The comparison of the desulfurization effect of the absorbent in this example on biogas and the traditional amine desulfurization is shown in Table 4.

[0088] Table 4

[0089]

[0090] As can be seen from Tables 1 to 4, the method provided by the present invention can efficiently remove inorganic sulfur and organic sulfur in various complex scenarios, and at the same time has good selectivity for CO2. The process flow is simple, the investment and operating costs are low, and it is easy to realize industrial production.

[0091] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A highly selective amine absorbent, characterized in that: The method comprises a main absorbent, an organic sulfur removal accelerator, an auxiliary agent and deionized water; the main absorbent comprises an alcohol amine containing a tertiary amine structure and / or containing steric hindrance; The alcoholamine containing a tertiary amine structure and / or a sterically hindered structure includes one or more of methyldiethanolamine, diisopropanolamine, 2-(tert-butylamino)ethanol, tert-butylaminoethoxyethanol and 2-amino-2-methyl-1-propanol; Organic sulfur removal promoters include (1H-pyrrol-3-yl)methylamine and N-methyltetrahydro-2H-thiopyran-4-amine; The auxiliary agents include preservatives, antioxidants and defoaming agents.

2. The highly selective amine absorbent according to claim 1, characterized in that: The main absorbent accounts for 15-40wt%, the organic sulfur removal accelerator accounts for 5-25wt%, the auxiliary agent accounts for 1-10wt%; and deionized water accounts for 20-70wt%.

3. The highly selective amine absorbent according to claim 1, characterized in that: The preservative includes benzotriazole or imidazoline derivatives, and the content of the preservative is 0.5 wt % to 2 wt %.

4. The highly selective amine absorbent according to claim 1, characterized in that: The antioxidant includes hydroquinone or butylated hydroxyanisole compounds, and the content of the antioxidant is 0.1 wt % to 1 wt %.

5. The highly selective amine absorbent according to claim 1, characterized in that: The defoaming agent includes polysiloxane or polyether compounds, and the content of the defoaming agent is 0.1 wt % to 0.5 wt %.

6. A method for preparing a highly selective amine absorbent according to any one of claims 1 to 5, characterized in that: The following steps are involved: Adding an alcoholamine containing a tertiary amine structure and / or a sterically hindered structure into a reactor, heating and stirring; adding an organic sulfur removal accelerator, heating and stirring to obtain a main absorbent mixed solution; dissolving the auxiliary agent in a solvent and heating to dissolve the auxiliary agent to obtain an auxiliary agent solution; The auxiliary agent solution is added to the main absorbent mixed solution, the temperature is controlled to be ≤50°C, and the mixture is stirred uniformly at a speed of 500-600 rpm to obtain the highly selective amine absorbent.

7. The preparation method according to claim 6, characterized in that The heating and stirring temperature is 40~50℃, the time is 20~40min, and the stirring speed is 200~300 rpm; The heating temperature is 40~80℃ and the time is 0.5~2 hours; The temperature for heating and dissolving is 30~60℃.

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