Desulfurizer and desulfurization method for sulfur-containing gas

Abstract

The present invention relates to the technical field of gas purification, and discloses a desulfurizer and a desulfurization method for a sulfur-containing gas. The desulfurizer comprises a first organic amine compound and a second organic amine compound. The mass ratio of the first organic amine compound to the second organic amine compound is 1:1-30, wherein the ratio of the Hückel charge quantity of the most electronegative nitrogen on the first organic amine compound to that of the most electronegative nitrogen on the second organic amine compound is 3-6.5:1. The desulfurizer has a pKa of 9.5-15. By using the desulfurizer of the present invention to purify a sulfur-containing gas having a high organic thiol content, a good purification effect can be achieved.

Description

Desulfurization methods for desulfurizing agents and sulfur-containing gases

[0001] Cross-reference to related applications

[0002] This application claims the benefit of Chinese patent application 202411830754.X, filed on December 12, 2024, the contents of which are incorporated herein by reference. Technical Field

[0003] This invention relates to the field of gas purification technology, specifically to a desulfurization agent and a desulfurization method for sulfur-containing gases. Background Technology

[0004] In the initial stage of operation of high-sulfur natural gas purification plants, the organic sulfur content in the feed gas often far exceeds the exploration value (organic sulfur content can reach 300-500 mg / m³). 3 Existing amine purification systems struggle to completely remove organic sulfur compounds under these conditions, with mercaptan removal being the most challenging. To meet Class I natural gas standards, the operating load of the amine purification unit must be significantly reduced. Furthermore, with the tightening of national natural gas standards (product gas H2S from 20 mg / m³...), the situation becomes increasingly complex. 3 Reduced to <6mg / m 3 Total sulfur content <200 mg / m³ 3 Reduced to <20mg / m 3 This also puts considerable pressure on the existing natural gas purification equipment.

[0005] The removal efficiency of thiols in existing amine solutions is extremely low. Firstly, the poor water solubility of thiols results in poor mass transfer and absorption in traditional amine solutions. Secondly, thiols are much less acidic than hydrogen sulfide and carbonic acid; therefore, after the amine solution absorbs acidic gases, the alkalinity of the traditional amine solution decreases, further reducing thiol absorption and even causing desorption of already absorbed thiols.

[0006] Currently, existing desulfurization methods mainly focus on H2S removal, with few reports on mercaptan removal. Quaker first disclosed in patent application US4978512A that a water-soluble triazine desulfurizer can be synthesized from alkylamines and aldehydes, describing the synthesis method of triazines with -OH groups and highlighting its advantages of high selectivity, rapid reaction, non-toxic products, and water solubility. Nalco / Exxon also mentioned in patent application US5674377A that an oil-soluble desulfurizer can be synthesized from alkylamines and aldehydes. Baker Hughes, in patent application US5554349A, described the highly efficient H2S removal properties of mixtures of combined amines and aldehydes. Summary of the Invention

[0007] The purpose of this invention is to overcome the problem of difficulty in removing organic thiols from sulfur-containing gases in existing technologies, and to provide a desulfurizing agent and a desulfurization method for sulfur-containing gases. The desulfurizing agent of this invention can be used for deep purification of sulfur-containing gases containing organic thiols.

[0008] To achieve the above objectives, the present invention provides a desulfurizing agent containing a first organic amine compound and a second organic amine compound, wherein the mass ratio of the first organic amine compound to the second organic amine compound is 1:1-30, wherein the Huckel charge ratio of nitrogen, the most electronegative element on the first organic amine compound and the second organic amine compound, is 3-6.5:1, and the pKa of the desulfurizing agent is 9.5-15.

[0009] A second aspect of the present invention provides a method for desulfurizing sulfur-containing gas, the method comprising: contacting the sulfur-containing gas with a desulfurizing agent, wherein the desulfurizing agent is the desulfurizing agent described above.

[0010] According to the technical solution of the present invention, by compounding two organic amine compounds with different alkalinities in a specific ratio, a synergistic effect can be formed, so that the desulfurizer of the present invention has a high desulfurization efficiency and can achieve deep purification of sulfur-containing gases with high organic thiol content. Detailed Implementation

[0011] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0012] The desulfurizing agent of the present invention contains a first organic amine compound and a second organic amine compound, wherein the ratio of the Huckel charge of nitrogen, which has the strongest electronegativity, on the first organic amine compound and the second organic amine compound is 3-6.5:1, preferably 3.2-6:1, and more preferably 3.5-5:1.

[0013] In this invention, the Huckel charge of nitrogen, the most electronegative element in organic amine compounds, is calculated using the Huckel molecular orbital method (software Chem3D).

[0014] The desulfurizing agent of the present invention has a pKa of 9.5-15, preferably 10-14.8, and more preferably 11-14.8.

[0015] In this invention, pKa refers to the acidity coefficient. The higher the pKa value of the desulfurizing agent, the stronger its alkalinity.

[0016] In the desulfurizing agent described in this invention, the mass ratio of the first organic amine compound to the second organic amine compound is 1:1-30, preferably 1:1.1-25, more preferably 1:1.5-20, further preferably 1:2-10, and even more preferably 1:3-8. When the first organic amine compound and the second organic amine compound are used in combination according to the above ratio, a synergistic effect can be formed, resulting in higher desulfurization efficiency, especially for sulfur-containing gases with high organic thiol content, exhibiting a better purification effect.

[0017] In the desulfurizing agent of the present invention, the Huckel charge of nitrogen, which has the strongest electronegativity on the first organic amine compound, is preferably -0.74 to -0.95. More preferably, the first organic amine compound is an organic base guanidine as shown in formula (I).

[0018] Among them, R 1 R 2 R 3 R 4 and R 5 Each is independently selected from hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted benzyl, and substituted or unsubstituted aromatic alkyl; or, R 5 With R 1 Or R 4 Ring formation, and / or R2 and R3 form a ring.

[0019] In this invention, "substituted or unsubstituted" means containing a substituent, which can be selected from halogens, hydroxyl groups, C1-C6 alkyl groups, halogenated C1-C6 alkyl groups, C1-C6 alkoxy groups and halogenated C1-C6 alkoxy groups.

[0020] In this invention, C1-C6 alkyl groups can be selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, n-pentyl, isopentyl, n-hexyl, isohexyl and 3,3-dimethylbutyl.

[0021] In the preferred case, in equation (I), R 1 R 2 R 3 R 4 and R 5 Each is independently selected from hydrogen, C1-C6 alkyl, and benzyl; or, R 5 With R 1 Or R 4 They form a six-membered ring, and R2 and R3 form a six-membered ring.

[0022] More preferably, the first organic amine compound is selected from at least one of guanidine, methylguanidine, tetramethylguanidine, trimethylguanidine, dimethylguanidine, 2-tert-butyl-1,1,3,3-tetramethylguanidine, diphenylguanidine, 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene and 1,5,7-triazabicyclo[4.4.0]dec-5-ene.

[0023] In the desulfurizing agent of the present invention, the Huckel charge of nitrogen, which has the strongest electronegativity on the second organic amine compound, is preferably -0.16 to -0.22. More preferably, the second organic amine compound is a triazine.

[0024] More preferably, the second organic amine compound is selected from triazine compounds represented by formula (II).

[0025] Among them, R 6 R 7 and R 8 Each is independently selected from one of C1-C6 alkyl, C2-C6 alkenyl, C1-C6 alkoxyalkyl and C1-C6 hydroxyalkyl.

[0026] More preferably, in order to further improve the removal effect of organothiols, the second organic amine compound is at least one selected from 1,3,5-tris-(2-hydroxyethyl)-hexahydro-S-triazine, 1,3,5-trimethylhexahydro-1,3,5-triazine, 1,3,5-triethyl-hexahydro-1,3,5-triazine, 1,3,5-tripropyl-hexahydro-1,3,5-triazine, 1,3,5-triallyl-hexahydro-1,3,5-triazine, and 1,3,5-tris(3-methoxypropyl)-hexahydro-1,3,5-triazine.

[0027] In some embodiments, the desulfurizing agent contains tetramethylguanidine and 1,3,5-tris-(2-hydroxyethyl)-hexahydro-S-triazine in a mass ratio of 1:2-10. The desulfurizing agent according to this embodiment exhibits high desulfurization efficiency and good deep purification effect on sulfur-containing gases with high organic thiol content.

[0028] In other embodiments, the desulfurizing agent contains 1,5,7-triazabicyclo[4.4.0]dec-5-ene and 1,3,5-tri-(2-hydroxyethyl)-hexahydro-S-triazine, with a mass ratio of 1:2-10. The desulfurizing agent according to this embodiment exhibits high desulfurization efficiency and good deep purification effect on sulfur-containing gases with high organic thiol content.

[0029] In other embodiments, the desulfurizing agent contains 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene and 1,3,5-tri-(2-hydroxyethyl)-hexahydro-S-triazine, with a mass ratio of 1:2-10. The desulfurizing agent according to this embodiment exhibits high desulfurization efficiency and good deep purification effect on sulfur-containing gases with high organic thiol content.

[0030] In a preferred embodiment, the desulfurizing agent of the present invention further contains water. Preferably, based on the total weight of the desulfurizing agent, the content of the first organic amine compound is 1-20 wt%, the content of the second organic amine compound is 30-70 wt%, and the water content is 10-65 wt%. More preferably, based on the total weight of the desulfurizing agent, the content of the first organic amine compound is 5-15 wt%, the content of the second organic amine compound is 40-60 wt%, and the water content is 25-55 wt%.

[0031] The desulfurization method for sulfur-containing gases according to the present invention includes contacting the sulfur-containing gas described above with a desulfurizing agent. The desulfurization method for sulfur-containing gases according to the present invention can achieve high desulfurization efficiency, especially showing good purification effect for sulfur-containing gases with high organic thiol content.

[0032] The desulfurization method for sulfur-containing gases described in this invention is particularly suitable for desulfurization processes using the direct injection method. Specifically, the process of contacting the sulfur-containing gas with the desulfurizing agent includes: directly injecting the desulfurizing agent into the feed gas pipeline used to transport the sulfur-containing gas.

[0033] During the contact process between the sulfur-containing gas and the desulfurizing agent, the gas-liquid ratio of the sulfur-containing gas to the desulfurizing agent can be 100-500:1, preferably 150-400:1, and more preferably 200-300:1.

[0034] During the contact process between the sulfur-containing gas and the desulfurizing agent, the pressure of the sulfur-containing gas can be 0.1-6 MPa, preferably 0.2-5 MPa, and more preferably 0.5-3 MPa. In this invention, the pressure of the sulfur-containing gas refers to absolute pressure.

[0035] The method described in this invention can desulfurize various conventional sulfur-containing gases, and is particularly suitable for the deep purification of sulfur-containing gases with high organic thiol content. In specific embodiments, the organic thiol content in the sulfur-containing gas can be 0-1000 ppmv, specifically, for example, 10 ppmv, 50 ppmv, 100 ppmv, 200 ppmv, 300 ppmv, 400 ppmv, 500 ppmv, 600 ppmv, 700 ppmv, 800 ppmv, 900 ppmv, or 1000 ppmv. In this invention, the organic thiol content in the sulfur-containing gas is calculated as elemental sulfur.

[0036] In the method described in this invention, the sulfur-containing gas may be selected from at least one of natural gas, coalbed methane, and oilfield gas.

[0037] The following examples further illustrate the desulfurization method for the desulfurizing agent and sulfur-containing gas described in this invention. These examples are implemented based on the technical solution of this invention, providing detailed implementation methods and specific operating procedures. However, the scope of protection of this invention is not limited to the following examples.

[0038] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods in the art. Unless otherwise specified, the experimental materials used in the following embodiments are commercially available.

[0039] In the following examples and comparative examples, the content of each component in the sulfur-containing gas was determined by coulometric analysis and chromatographic methods, and the thiol content was expressed as elemental sulfur.

[0040] Example 1

[0041] (1) Preparation of desulfurizing agent

[0042] 50g of 1,3,5-tri-(2-hydroxyethyl)-hexahydro-S-triazine, 10g of tetramethylguanidine, and 40g of water were weighed and mixed to obtain desulfurizing agent A1, which has a pKa of 14.2. The Huckel charge of the nitrogen atom with the strongest electronegativity on tetramethylguanidine is -0.947; the Huckel charge of the nitrogen atom with the strongest electronegativity on 1,3,5-tri-(2-hydroxyethyl)-hexahydro-S-triazine is -0.211; and the ratio of the Huckel charges of tetramethylguanidine to those of the nitrogen atom with the strongest electronegativity on 1,3,5-tri-(2-hydroxyethyl)-hexahydro-S-triazine is 4.5:1.

[0043] (2) Desulfurization treatment

[0044] The feed gas contains 80 ppmv of CH3SH, 20 ppmv of C2H5SH, and the remainder is N2. The pressure of the feed gas is 1 MPa and the temperature is 25℃.

[0045] The desulfurizing agent A1 is directly injected into the raw gas pipeline used to transport the raw gas, and desulfurization is carried out under the condition of gas-liquid ratio of 200:1. The purified gas has a CH3SH content of 1.5 ppmv and a C2H5SH content of 0.6 ppmv.

[0046] Example 2

[0047] (1) Preparation of desulfurizing agent

[0048] 50g of 1,3,5-tri-(2-hydroxyethyl)-hexahydro-S-triazine, 5g of tetramethylguanidine, and 45g of water were weighed and mixed to obtain desulfurizing agent A2, which has a pKa of 14.2. The Huckel charge of the nitrogen with the strongest electronegativity on tetramethylguanidine is -0.947; the Huckel charge of the nitrogen with the strongest electronegativity on 1,3,5-tri-(2-hydroxyethyl)-hexahydro-S-triazine is -0.211; and the ratio of the Huckel charges of tetramethylguanidine and the nitrogen with the strongest electronegativity on 1,3,5-tri-(2-hydroxyethyl)-hexahydro-S-triazine is 4.5:1.

[0049] (2) Desulfurization treatment

[0050] The feed gas contains 80 ppmv of CH3SH, 20 ppmv of C2H5SH, and the remainder is N2. The pressure of the feed gas is 1 MPa and the temperature is 25℃.

[0051] The desulfurizing agent A2 was directly injected into the raw gas pipeline used to transport the raw gas and desulfurized under the condition of a gas-liquid ratio of 200:1. The purified gas obtained contained 2.1 ppmv of CH3SH and 0.9 ppmv of C2H5SH.

[0052] Example 3

[0053] (1) Preparation of desulfurizing agent

[0054] 40g of 1,3,5-tri-(2-hydroxyethyl)-hexahydro-S-triazine, 15g of tetramethylguanidine, and 45g of water were weighed and mixed to obtain desulfurizing agent A3, which has a pKa of 14.2. The Huckel charge of the nitrogen atom with the strongest electronegativity on tetramethylguanidine is -0.947; the Huckel charge of the nitrogen atom with the strongest electronegativity on 1,3,5-tri-(2-hydroxyethyl)-hexahydro-S-triazine is -0.211; and the ratio of the Huckel charges of tetramethylguanidine to those of the nitrogen atom with the strongest electronegativity on 1,3,5-tri-(2-hydroxyethyl)-hexahydro-S-triazine is 4.5:1.

[0055] (2) Desulfurization treatment

[0056] The feed gas contains 80 ppmv of CH3SH, 20 ppmv of C2H5SH, and the remainder is N2. The pressure of the feed gas is 1 MPa and the temperature is 25℃.

[0057] The desulfurizing agent A3 was directly injected into the raw gas pipeline used to transport the raw gas and desulfurized under the condition of a gas-liquid ratio of 200:1. The CH3SH content in the purified gas was 1.2 ppmv, and C2H5SH was not detected.

[0058] Example 4

[0059] (1) Preparation of desulfurizing agent

[0060] Desulfurizer A4 was prepared according to the method of Example 1, except that 1,5,7-triazabicyclo[4.4.0]dec-5-ene was used in place of tetramethylguanidine by mass, and the pKa of desulfurizer A4 was 14.1. The Huckel charge of the nitrogen with the strongest electronegativity on 1,5,7-triazabicyclo[4.4.0]dec-5-ene was -0.744; the Huckel charge of the nitrogen with the strongest electronegativity on 1,3,5-tri-(2-hydroxyethyl)-hexahydro-S-triazine was -0.211; and the ratio of the Huckel charges of the nitrogen with the strongest electronegativity on 1,5,7-triazabicyclo[4.4.0]dec-5-ene to that on 1,3,5-tri-(2-hydroxyethyl)-hexahydro-S-triazine was 3.5:1.

[0061] (2) Desulfurization treatment

[0062] The desulfurization process was carried out according to the method of Example 1, except that the desulfurizing agent A4 was used instead of the desulfurizing agent A1.

[0063] The final purified gas contained 1.6 ppmv of CH3SH and 0.5 ppmv of C2H5SH.

[0064] Example 5

[0065] (1) Preparation of desulfurizing agent

[0066] Desulfurizer A5 was prepared according to the method of Example 1, except that 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene was used in place of tetramethylguanidine by mass, and the pKa of desulfurizer A5 was 13.1. The Huckel charge of the nitrogen with the strongest electronegativity on 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene was -0.744; the Huckel charge of the nitrogen with the strongest electronegativity on 1,3,5-tri-(2-hydroxyethyl)-hexahydro-S-triazine was -0.211; and the ratio of the Huckel charges of the nitrogen with the strongest electronegativity on 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene to that on 1,3,5-tri-(2-hydroxyethyl)-hexahydro-S-triazine was 3.5:1.

[0067] (2) Desulfurization treatment

[0068] The desulfurization process was carried out according to the method of Example 1, except that the desulfurizing agent A5 was used instead of the desulfurizing agent A1.

[0069] The final purified gas contained 2.2 ppmv of CH3SH and 0.9 ppmv of C2H5SH.

[0070] Example 6

[0071] The method was implemented according to Example 1, except that the gas-liquid ratio was 300:1.

[0072] The final purified gas contained 1.7 ppmv of CH3SH and 0.7 ppmv of C2H5SH.

[0073] Example 7

[0074] The method was implemented according to Example 1, except that the gas-liquid ratio was 400:1.

[0075] The final purified gas contained 3.8 ppmv of CH3SH and 1.7 ppmv of C2H5SH.

[0076] Example 8

[0077] The method was implemented according to Example 1, except that the gas-liquid ratio was 500:1.

[0078] The final purified gas contained 13.9 ppmv of CH3SH and 5.5 ppmv of C2H5SH.

[0079] Example 9

[0080] The method was implemented according to Example 1, except that the gas-liquid ratio was 100:1.

[0081] The final purified gas contained 0.9 ppmv of CH3SH, and C2H5SH was not detected. This demonstrates that a lower gas-liquid ratio results in better purification.

[0082] Example 10

[0083] The method was implemented according to Example 1, except that the content of CH3SH in the feed gas was 500 ppmv, the content of C2H5SH was 100 ppmv, and the remainder was N2.

[0084] The final purified gas contained 15.6 ppmv of CH3SH and 4.4 ppmv of C2H5SH.

[0085] Example 11

[0086] The method was implemented according to Example 1, except that the pressure of the raw material gas was 3 MPa.

[0087] The final purified gas contained 1.4 ppmv of CH3SH and 0.5 ppmv of C2H5SH.

[0088] Example 12

[0089] The method was implemented according to Example 1, except that the pressure of the raw material gas was 0.5 MPa.

[0090] The final purified gas contained 3.1 ppmv of CH3SH and 1.0 ppmv of C2H5SH.

[0091] Example 13

[0092] (1) Preparation of desulfurizing agent

[0093] Desulfurizer A13 was prepared according to the method of Example 1, except that diphenylguanidine was used in place of tetramethylguanidine by mass, and the pKa of desulfurizer A13 was 11.3. The Huckel charge of the nitrogen with the strongest electronegativity on diphenylguanidine was -0.817; the Huckel charge of the nitrogen with the strongest electronegativity on 1,3,5-tri-(2-hydroxyethyl)-hexahydro-S-triazine was -0.211; and the ratio of the Huckel charges of diphenylguanidine to those of the nitrogen with the strongest electronegativity on 1,3,5-tri-(2-hydroxyethyl)-hexahydro-S-triazine was 3.9:1.

[0094] (2) Desulfurization treatment

[0095] The desulfurization process was carried out according to the method of Example 1, except that the desulfurizing agent A13 was used instead of the desulfurizing agent A1.

[0096] The final purified gas contained 6.0 ppmv of CH3SH and 3.3 ppmv of C2H5SH.

[0097] Example 14

[0098] (1) Preparation of desulfurizing agent

[0099] Desulfurizer A14 was prepared according to the method of Example 1, except that dimethyl guanidine was used in place of tetramethyl guanidine by mass, and the pKa of desulfurizer A14 was 13.3. The Huckel charge of the nitrogen with the strongest electronegativity on dimethyl guanidine was -0.942; the Huckel charge of the nitrogen with the strongest electronegativity on 1,3,5-tri-(2-hydroxyethyl)-hexahydro-S-triazine was -0.211; and the ratio of the Huckel charges of dimethyl guanidine to those of the nitrogen with the strongest electronegativity on 1,3,5-tri-(2-hydroxyethyl)-hexahydro-S-triazine was 4.5:1.

[0100] (2) Desulfurization treatment

[0101] The desulfurization process was carried out according to the method of Example 1, except that the desulfurizing agent A14 was used instead of the desulfurizing agent A1.

[0102] The final purified gas contained 2.0 ppmv of CH3SH and 1.2 ppmv of C2H5SH.

[0103] Example 15

[0104] (1) Preparation of desulfurizing agent

[0105] Desulfurizer A15 was prepared according to the method of Example 1, except that trimethylguanidine was used in place of tetramethylguanidine by mass, and the pKa of desulfurizer A15 was 13.0. The Huckel charge of the nitrogen with the strongest electronegativity on trimethylguanidine was -0.816; the Huckel charge of the nitrogen with the strongest electronegativity on 1,3,5-tri-(2-hydroxyethyl)-hexahydro-S-triazine was -0.211; and the ratio of the Huckel charges of trimethylguanidine to those of the nitrogen with the strongest electronegativity on 1,3,5-tri-(2-hydroxyethyl)-hexahydro-S-triazine was 3.9:1.

[0106] (2) Desulfurization treatment

[0107] The desulfurization process was carried out according to the method of Example 1, except that the desulfurizing agent A15 was used instead of the desulfurizing agent A1.

[0108] The final purified gas contained 2.2 ppmv of CH3SH and 1.3 ppmv of C2H5SH.

[0109] Example 16

[0110] (1) Preparation of desulfurizing agent

[0111] Desulfurizer A16 was prepared according to the method of Example 1, except that 1,3,5-trimethylhexahydro-1,3,5-triazine was used in place of 1,3,5-tri-(2-hydroxyethyl)-hexahydro-S-triazine by mass. The pKa of desulfurizer A16 was 14.1. The Huckel charge of the nitrogen with the strongest electronegativity on tetramethylguanidine was -0.947; the Huckel charge of the nitrogen with the strongest electronegativity on 1,3,5-trimethylhexahydro-1,3,5-triazine was -0.197; and the ratio of the Huckel charges of tetramethylguanidine and the nitrogen with the strongest electronegativity on 1,3,5-trimethylhexahydro-1,3,5-triazine was 4.8:1.

[0112] (2) Desulfurization treatment

[0113] The desulfurization process was carried out according to the method of Example 1, except that the desulfurizing agent A16 was used instead of the desulfurizing agent A1.

[0114] The final purified gas contained 1.7 ppmv of CH3SH and 1.2 ppmv of C2H5SH.

[0115] Example 17

[0116] (1) Preparation of desulfurizing agent

[0117] Desulfurizer A17 was prepared according to the method of Example 1, except that guanidine was used in place of tetramethylguanidine by mass, and the pKa of desulfurizer A17 was 13.7. The Huckel charge of the nitrogen with the strongest electronegativity on guanidine was -0.891; the Huckel charge of the nitrogen with the strongest electronegativity on 1,3,5-tri-(2-hydroxyethyl)-hexahydro-S-triazine was -0.211; and the ratio of the Huckel charges of guanidine to those of the nitrogen with the strongest electronegativity on 1,3,5-tri-(2-hydroxyethyl)-hexahydro-S-triazine was 4.2:1.

[0118] (2) Desulfurization treatment

[0119] The desulfurization process was carried out according to the method of Example 1, except that the desulfurizing agent A17 was used instead of the desulfurizing agent A1.

[0120] The final purified gas contained 2.2 ppmv of CH3SH and 1.3 ppmv of C2H5SH.

[0121] Example 18

[0122] (1) Preparation of desulfurizing agent

[0123] Desulfurizer A18 was prepared according to the method of Example 1, except that methylguanidine was used in place of tetramethylguanidine by mass, and the pKa of desulfurizer A18 was 13.2. The Huckel charge of the nitrogen with the strongest electronegativity on methylguanidine was -0.899; the Huckel charge of the nitrogen with the strongest electronegativity on 1,3,5-tri-(2-hydroxyethyl)-hexahydro-S-triazine was -0.211; and the ratio of the Huckel charges of methylguanidine to those of the nitrogen with the strongest electronegativity on 1,3,5-tri-(2-hydroxyethyl)-hexahydro-S-triazine was 4.3:1.

[0124] (2) Desulfurization treatment

[0125] The desulfurization process was carried out according to the method of Example 1, except that the desulfurizing agent A18 was used instead of the desulfurizing agent A1.

[0126] The final purified gas contained 2.4 ppmv of CH3SH and 1.3 ppmv of C2H5SH.

[0127] Example 19

[0128] (1) Preparation of desulfurizing agent

[0129] Desulfurizer A19 was prepared according to the method of Example 1, except that 2-tert-butyl-1,1,3,3-tetramethylguanidine was used in place of tetramethylguanidine by mass. The pKa of desulfurizer A19 was 12.6. The Huckel charge of the nitrogen with the strongest electronegativity on 2-tert-butyl-1,1,3,3-tetramethylguanidine was -0.763; the Huckel charge of the nitrogen with the strongest electronegativity on 1,3,5-tris-(2-hydroxyethyl)-hexahydro-S-triazine was -0.211; and the ratio of the Huckel charges of the nitrogen with the strongest electronegativity on 2-tert-butyl-1,1,3,3-tetramethylguanidine to that on 1,3,5-tris-(2-hydroxyethyl)-hexahydro-S-triazine was 3.6:1.

[0130] (2) Desulfurization treatment

[0131] The desulfurization process was carried out according to the method of Example 1, except that the desulfurizing agent A19 was used instead of the desulfurizing agent A1.

[0132] The final purified gas contained 3.2 ppmv of CH3SH and 1.7 ppmv of C2H5SH.

[0133] Example 20

[0134] (1) Preparation of desulfurizing agent

[0135] Desulfurizer A20 was prepared according to the method of Example 1, except that 1,3,5-triethyl-hexahydro-1,3,5-triazine was used in place of 1,3,5-tri-(2-hydroxyethyl)-hexahydro-S-triazine by mass. The pKa of desulfurizer A20 was 13.7. The Huckel charge of the nitrogen with the strongest electronegativity on tetramethylguanidine was -0.947; the Huckel charge of the nitrogen with the strongest electronegativity on 1,3,5-triethyl-hexahydro-1,3,5-triazine was -0.202; and the ratio of the Huckel charges of tetramethylguanidine and the nitrogen with the strongest electronegativity on 1,3,5-triethyl-hexahydro-1,3,5-triazine was 4.7:1.

[0136] (2) Desulfurization treatment

[0137] The desulfurization process was carried out according to the method of Example 1, except that the desulfurizing agent A20 was used instead of the desulfurizing agent A1.

[0138] The final purified gas contained 2.0 ppmv of CH3SH and 1.3 ppmv of C2H5SH.

[0139] Example 21

[0140] (1) Preparation of desulfurizing agent

[0141] Desulfurizer A21 was prepared according to the method of Example 1, except that 1,3,5-tripropyl-hexahydro-1,3,5-triazine was replaced by an equal mass of 1,3,5-tri-(2-hydroxyethyl)-hexahydro-S-triazine. The pKa of desulfurizer A21 was 13.8. The Huckel charge of the nitrogen with the strongest electronegativity on tetramethylguanidine was -0.947; the Huckel charge of the nitrogen with the strongest electronegativity on 1,3,5-tripropyl-hexahydro-1,3,5-triazine was -0.203; and the ratio of the Huckel charges of tetramethylguanidine and the nitrogen with the strongest electronegativity on 1,3,5-tripropyl-hexahydro-1,3,5-triazine was 4.7:1.

[0142] (2) Desulfurization treatment

[0143] The desulfurization process was carried out according to the method of Example 1, except that the desulfurizing agent A21 was used instead of the desulfurizing agent A1.

[0144] The final purified gas contained 1.8 ppmv of CH3SH and 1.2 ppmv of C2H5SH.

[0145] Example 22

[0146] (1) Preparation of desulfurizing agent

[0147] Desulfurizer A22 was prepared according to the method of Example 1, except that 1,3,5-tri-(2-hydroxyethyl)-hexahydro-S-triazine was replaced by an equal mass of 1,3,5-triallyl-hexahydro-1,3,5-triazine. The pKa of desulfurizer A22 was 13.1. The Huckel charge of the nitrogen with the strongest electronegativity on tetramethylguanidine was -0.947; the Huckel charge of the nitrogen with the strongest electronegativity on 1,3,5-triallyl-hexahydro-1,3,5-triazine was -0.170; and the ratio of the Huckel charges of tetramethylguanidine and the nitrogen with the strongest electronegativity on 1,3,5-triallyl-hexahydro-1,3,5-triazine was 5.6:1.

[0148] (2) Desulfurization treatment

[0149] The desulfurization process was carried out according to the method of Example 1, except that the desulfurizing agent A22 was used instead of the desulfurizing agent A1.

[0150] The final purified gas contained 3.2 ppmv of CH3SH and 1.9 ppmv of C2H5SH.

[0151] Example 23

[0152] (1) Preparation of desulfurizing agent

[0153] Desulfurizer A23 was prepared according to the method of Example 1, except that 1,3,5-tris(3-methoxypropyl)-hexahydro-1,3,5-triazine was used in place of 1,3,5-tri-(2-hydroxyethyl)-hexahydro-S-triazine by mass. The pKa of desulfurizer A23 was 13.9. The Huckel charge of the nitrogen with the strongest electronegativity on tetramethylguanidine was -0.947; the Huckel charge of the nitrogen with the strongest electronegativity on 1,3,5-tris(3-methoxypropyl)-hexahydro-1,3,5-triazine was -0.203; and the ratio of the Huckel charges of tetramethylguanidine and the nitrogen with the strongest electronegativity on 1,3,5-tris(3-methoxypropyl)-hexahydro-1,3,5-triazine was 4.7:1.

[0154] (2) Desulfurization treatment

[0155] The desulfurization process was carried out according to the method of Example 1, except that the desulfurizing agent A23 was used instead of the desulfurizing agent A1.

[0156] The final purified gas contained 1.4 ppmv of CH3SH and 1.9 ppmv of C2H5SH.

[0157] Comparative Example 1

[0158] (1) Preparation of desulfurizing agent

[0159] 60g of 1,3,5-tris-(2-hydroxyethyl)-hexahydro-S-triazine and 40g of water were stirred and mixed to obtain desulfurizer D1, which means that desulfurizer D1 does not contain organic base guanidine.

[0160] (2) Desulfurization treatment

[0161] The desulfurization process was carried out according to the method of Example 1, except that the desulfurizing agent D1 was used instead of the desulfurizing agent A1.

[0162] The final purified gas contained 18.1 ppmv of CH3SH and 9.4 ppmv of C2H5SH.

[0163] Comparative Example 2

[0164] (1) Preparation of desulfurizing agent

[0165] 60g of tetramethylguanidine and 40g of water were mixed to obtain desulfurizer D2, which means that desulfurizer D2 does not contain triazine.

[0166] (2) Desulfurization treatment

[0167] The desulfurization process was carried out according to the method of Example 1, except that the desulfurizing agent D2 was used instead of the desulfurizing agent A1.

[0168] The final purified gas contained 15.3 ppmv of CH3SH and 7.7 ppmv of C2H5SH.

[0169] Comparative Example 3

[0170] (1) Preparation of desulfurizing agent

[0171] Weigh 58.5g of 1,3,5-tris-(2-hydroxyethyl)-hexahydro-S-triazine, 1.5g of tetramethylguanidine, and 40g of water and mix them to obtain desulfurizing agent D3.

[0172] (2) Desulfurization treatment

[0173] The desulfurization process was carried out according to the method of Example 1, except that the desulfurizing agent D3 was used instead of the desulfurizing agent A1.

[0174] The final purified gas contained 12.2 ppmv of CH3SH and 6.2 ppmv of C2H5SH.

[0175] Comparative Example 4

[0176] (1) Preparation of desulfurizing agent

[0177] Weigh 25g of 1,3,5-tris-(2-hydroxyethyl)-hexahydro-S-triazine, 35g of tetramethylguanidine and 40g of water and stir to obtain desulfurizer D4.

[0178] (2) Desulfurization treatment

[0179] The desulfurization process was carried out according to the method of Example 1, except that the desulfurizing agent D4 was used instead of the desulfurizing agent A1.

[0180] The final purified gas contained 9.8 ppmv of CH3SH and 4.1 ppmv of C2H5SH.

[0181] Comparative Example 5

[0182] (1) Preparation of desulfurizing agent

[0183] Desulfurizer D5 was prepared according to the method of Example 1, except that 1,3,5-tris-(2-hydroxyethyl)-hexahydro-S-triazine was replaced by an equal mass of 2-vinyl-4,6-diamino-triazine. The pKa of the desulfurizer A16 was 15.5. The Huckel charge of the nitrogen with the strongest electronegativity on tetramethylguanidine was -0.947; the Huckel charge of the nitrogen with the strongest electronegativity on 2-vinyl-4,6-diamino-triazine was -0.639; and the ratio of the Huckel charges of tetramethylguanidine and the nitrogen with the strongest electronegativity on 2-vinyl-4,6-diamino-triazine was 1.48:1.

[0184] (2) Desulfurization treatment

[0185] The desulfurization process was carried out according to the method of Example 1, except that the desulfurizing agent D5 was used instead of the desulfurizing agent A1.

[0186] The final purified gas contained 11.8 ppmv of CH3SH and 5.4 ppmv of C2H5SH.

[0187] As can be seen from the structures of the above embodiments and comparative examples, the desulfurizing agent of the present invention can achieve a good purification effect when used to purify sulfur-containing gases with high organic thiol content.

[0188] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A desulfurizing agent, characterized in that, The desulfurizing agent contains a first organic amine compound and a second organic amine compound, wherein the mass ratio of the first organic amine compound to the second organic amine compound is 1:1-30, wherein the Huckel charge ratio of nitrogen, which has the strongest electronegativity, on the first organic amine compound and the second organic amine compound is 3-6.5:1, and the pKa of the desulfurizing agent is 9.5-15.

2. The desulfurizing agent according to claim 1, characterized in that, The mass ratio of the first organic amine compound to the second organic amine compound is 1:2-10.

3. The desulfurizing agent according to claim 1 or 2, characterized in that, The Huckel charge of nitrogen, the most electronegative element in the first organic amine compound, ranges from -0.74 to -0.

95.

4. The desulfurizing agent according to any one of claims 1-3, characterized in that, The first organic amine compound is an organic base guanidine as shown in formula (I). Among them, R 1 R 2 R 3 R 4 and R 5 Each is independently selected from hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted benzyl, and substituted or unsubstituted aromatic alkyl; or, R 5 With R 1 Or R 4 Ring formation, and / or R2 and R3 form a ring.

5. The desulfurizing agent according to claim 4, characterized in that, In equation (I), R 1 R 2 R 3 R 4 and R 5 Each is independently selected from hydrogen, C1-C6 alkyl, and benzyl; or, R 5 With R 1 Or R 4 They form a six-membered ring, and R2 and R3 form a six-membered ring.

6. The desulfurizing agent according to claim 5, characterized in that, The first organic amine compound is selected from at least one of guanidine, methylguanidine, tetramethylguanidine, trimethylguanidine, dimethylguanidine, 2-tert-butyl-1,1,3,3-tetramethylguanidine, diphenylguanidine, 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene and 1,5,7-triazabicyclo[4.4.0]dec-5-ene.

7. The desulfurizing agent according to claim 1 or 2, characterized in that, The Huckel charge of nitrogen, the most electronegative element in the second organic amine compound, is -0.16 to -0.

22.

8. The desulfurizing agent according to claim 1, 2, or 7, characterized in that, The second organic amine compound is a triazine.

9. The desulfurizing agent according to claim 8, characterized in that, The structural formula of the second organic amine compound is shown in formula (II). Among them, R 6 R 7 and R 8 Each is independently selected from one of C1-C6 alkyl, C2-C6 alkenyl, C1-C6 alkoxyalkyl and C1-C6 hydroxyalkyl.

10. The desulfurizing agent according to claim 9, characterized in that, The second organic amine compound is at least one of 1,3,5-tris-(2-hydroxyethyl)-hexahydro-S-triazine, 1,3,5-trimethylhexahydro-1,3,5-triazine, 1,3,5-triethyl-hexahydro-1,3,5-triazine, 1,3,5-tripropyl-hexahydro-1,3,5-triazine, 1,3,5-triallyl-hexahydro-1,3,5-triazine, and 1,3,5-tris(3-methoxypropyl)-hexahydro-1,3,5-triazine.

11. The desulfurizing agent according to any one of claims 1-10, characterized in that, The desulfurizing agent also contains water, and based on the total weight of the desulfurizing agent, the content of the first organic amine compound is 1-20 wt%, the content of the second organic amine compound is 30-70 wt%, and the content of water is 10-65 wt%.

12. The desulfurizing agent according to claim 11, characterized in that, Based on the total weight of the desulfurizing agent, the content of the first organic amine compound is 5-15 wt%, the content of the second organic amine compound is 40-60 wt%, and the content of water is 25-55 wt%.

13. A method for desulfurizing sulfur-containing gas, the method comprising: The sulfur-containing gas is brought into contact with a desulfurizing agent, characterized in that the desulfurizing agent is the desulfurizing agent according to any one of claims 1-12.

14. The method according to claim 13, characterized in that, The process of contacting sulfur-containing gas with a desulfurizing agent includes: directly injecting the desulfurizing agent into the raw gas pipeline used to transport the sulfur-containing gas.

15. The method according to claim 13 or 14, characterized in that, During the contact process between the sulfur-containing gas and the desulfurizing agent, the gas-liquid ratio of the sulfur-containing gas to the desulfurizing agent is 100-500:1, preferably 150-400:1, and more preferably 200-300:

1.

16. The method according to claim 13 or 14, characterized in that, During the contact process between the sulfur-containing gas and the desulfurizing agent, the pressure of the sulfur-containing gas is 0.1-6 MPa, preferably 0.2-5 MPa.

17. The method according to any one of claims 13-16, characterized in that, The content of organic thiols in the sulfur-containing gas is 0-1000 ppmv.

18. The method according to any one of claims 13-17, characterized in that, The sulfur-containing gas is selected from at least one of natural gas, coalbed methane, and oilfield gas.

Images