Hydrogen sulfide removal catalyst and method of making same

Abstract

The application discloses a hydrogen sulfide removal catalyst and a preparation method thereof, and comprises a catalyst carrier, an active component, a structure directing agent, a binder and deionized water; the structure directing agent is composed of an asymmetric Gemini quaternary ammonium salt surfactant and a chitosan polycationic surfactant; the catalyst is prepared by the following steps: S1, mixing the catalyst carrier, the active component and the deionized water to obtain a mixture A; S2, adding the structure directing agent and the binder into the mixture A and mixing to obtain a mixture B; and S3, drying and calcining the mixture B to obtain the hydrogen sulfide removal catalyst. The catalyst has excellent hydrogen sulfide removal performance.

Description

Technical Field

[0001] This invention relates to the field of catalyst technology, and more particularly to desulfurization catalysts and their preparation methods. Background Technology

[0002] Currently, the methods for removing hydrogen sulfide on the market are generally divided into wet and dry desulfurization. Wet desulfurization includes organic ammonium and sodium-based alkaline solution desulfurization, while dry desulfurization includes molecular sieve physical adsorption, iron oxide absorption, and carbon-based catalysis. Both of these hydrogen sulfide treatment methods suffer from high investment costs and large operation and maintenance management expenses. Meanwhile, carbon-based catalytic desulfurization typically operates at temperatures above 80°C and has a relatively low sulfur capacity. Therefore, there is an urgent need to develop a new hydrogen sulfide removal catalyst to solve the above-mentioned technical problems. Summary of the Invention

[0003] Based on the technical problems existing in the background art, the present invention proposes a desulfurization catalyst and its preparation method, which has excellent desulfurization performance.

[0004] The desulfurization catalyst proposed in this invention comprises the following raw materials in parts by weight: 80-120 parts catalyst support, 1-10 parts active component, 1-5 parts structure directing agent, 1-5 parts binder, and 10-30 parts deionized water.

[0005] Preferably, the structure-directing agent is composed of an asymmetric Gemini quaternary ammonium salt surfactant and a chitosan polycationic surfactant in a mass ratio of 4:1-4.

[0006] Preferably, the asymmetric Gemini quaternary ammonium salt surfactant is prepared from cocoylpropyl dimethyl tertiary amine, dodecylpropyl dimethyl tertiary amine and epichlorohydrin.

[0007] Preferably, the chitosan polycationic surfactant is one or more of 6-O-p-toluenesulfonyl-N,N,N-trimethyl chitosan quaternary ammonium salt, 6-aminohexylamino-6-deoxy-N,N,N-trimethyl chitosan quaternary ammonium salt, and 6-aminoethylamino-6-deoxy-N,N,N-trimethyl chitosan quaternary ammonium salt.

[0008] Preferably, the catalyst support is activated carbon, and the specific surface area of ​​the activated carbon is 700-1000 m². 2 / g, pore volume 0.5-1m 3 / g, average pore size 10-30nm.

[0009] Preferably, the active component is composed of phosphomolybdic acid, ZrOCl2·8H2O, CeCl3·7H2O and 50% Mn(NO3)2 aqueous solution in a mass ratio of 1:0.1-10:0.1-10:0.1-10.

[0010] Preferably, the binder is one or more of sodium carboxymethyl cellulose, sodium stearate, polyethylene oxide, hydrated aluminum oxide, hydrated silica, and diatomaceous earth.

[0011] The preparation method of the above-mentioned desulfurization catalyst proposed in this invention comprises the following steps:

[0012] S1: Thoroughly mix the catalyst support, active components, and deionized water to obtain mixture A;

[0013] S2: Add structure-directing agent and binder to mixture A and mix thoroughly to obtain mixture B;

[0014] S3: The mixture B is dried and calcined to obtain the desulfurization catalyst.

[0015] Preferably, the drying temperature in S3 is 80-100℃ and the time is 1-3h; the calcination temperature is 300-500℃ and the time is 4-8h.

[0016] The present invention relates to the application of the above-mentioned desulfurization catalyst in the removal of hydrogen sulfide from gases.

[0017] Beneficial technical effects of the present invention:

[0018] (1) When the mixture of the present invention is calcined, due to the effect of the structure directing agent, the active components are fully attached to the surface of the activated carbon, and the specific surface area of ​​the catalyst is larger, so that the catalyst has good desulfurization performance and better stability. In addition, the structure directing agent of the present invention is composed of asymmetric Gemini quaternary ammonium salt surfactant and chitosan polycationic surfactant, which has a synergistic promoting effect on improving the desulfurization performance of the catalyst.

[0019] (2) The active component of the present invention is composed of phosphomolybdic acid, ZrOCl2·8H2O, CeCl3·7H2O and 50% Mn(NO3)2 aqueous solution. Phospholybdic acid acts as both an acidic medium and a catalytic active site. Under the combined action of ZrOCl2·8H2O, CeCl3·7H2O and 50% Mn(NO3)2 aqueous solution, the ultra-low temperature performance of the catalyst for desulfurization can be significantly improved. The working sulfur capacity is as high as 40% or more at a reaction temperature of 60°C, which is suitable for the actual working conditions of biogas production in current anaerobic digesters. Detailed Implementation

[0020] The present invention will be further explained below with reference to specific embodiments.

[0021] Example 1

[0022] The desulfurization catalyst proposed in this invention comprises the following raw materials in parts by weight: 100 parts catalyst support, 5 parts active component, 3 parts structure directing agent, 3 parts sodium carboxymethyl cellulose, and 20 parts deionized water.

[0023] The structure-directing agent is composed of an asymmetric Gemini quaternary ammonium salt surfactant and a chitosan polycationic surfactant in a 2:1 mass ratio.

[0024] Among them, the asymmetric Gemini quaternary ammonium salt surfactant is prepared from cocoylpropyl dimethyl tertiary amine, dodecylpropyl dimethyl tertiary amine and epichlorohydrin.

[0025] The chitosan polycationic surfactant is 6-aminohexylamino-6-deoxy-N,N,N-trimethylchitosan quaternary ammonium salt.

[0026] The catalyst support is activated carbon, with a specific surface area of ​​850 m². 2 / g, pore volume 0.8m 3 / g, average pore size 20nm.

[0027] The active component is composed of phosphomolybdic acid, ZrOCl2·8H2O, CeCl3·7H2O and 50% Mn(NO3)2 aqueous solution in a mass ratio of 1:1:1:1.

[0028] The preparation method of the above-mentioned desulfurization catalyst proposed in this invention comprises the following steps:

[0029] S1: Thoroughly mix the catalyst support, active components, and deionized water to obtain mixture A;

[0030] S2: Add structure-directing agent and binder to mixture A and mix thoroughly to obtain mixture B;

[0031] S3: The mixture B is dried and calcined to obtain the desulfurization catalyst.

[0032] The drying temperature in S3 is 90℃ for 2 hours; the calcination temperature is 400℃ for 6 hours.

[0033] Example 2

[0034] The desulfurization catalyst proposed in this invention comprises the following raw materials in parts by weight: 80 parts catalyst support, 1 part active component, 1 part structure directing agent, 1 part sodium stearate, and 10 parts deionized water.

[0035] The structure-directing agent is composed of an asymmetric Gemini quaternary ammonium salt surfactant and a chitosan polycationic surfactant in a mass ratio of 4:1.

[0036] Among them, the asymmetric Gemini quaternary ammonium salt surfactant is prepared from cocoylpropyl dimethyl tertiary amine, dodecylpropyl dimethyl tertiary amine and epichlorohydrin.

[0037] The chitosan polycationic surfactant is 6-O-p-toluenesulfonyl-N,N,N-trimethylchitosan quaternary ammonium salt.

[0038] The catalyst support is activated carbon, with a specific surface area of ​​850 m². 2 / g, pore volume 0.8m 3 / g, average pore size 20nm.

[0039] The active components consist of phosphomolybdic acid, ZrOCl2·8H2O, CeCl3·7H2O and 50% Mn(NO3)2 aqueous solution in a mass ratio of 10:1:1:1.

[0040] The preparation method of the above-mentioned desulfurization catalyst proposed in this invention comprises the following steps:

[0041] S1: Thoroughly mix the catalyst support, active components, and deionized water to obtain mixture A;

[0042] S2: Add structure-directing agent and binder to mixture A and mix thoroughly to obtain mixture B;

[0043] S3: The mixture B is dried and calcined to obtain the desulfurization catalyst.

[0044] The drying temperature in S3 is 80℃ for 3 hours; the calcination temperature is 300℃ for 8 hours.

[0045] Example 3

[0046] The desulfurization catalyst proposed in this invention comprises the following raw materials in parts by weight: 120 parts catalyst support, 10 parts active component, 5 parts structure directing agent, 5 parts hydrated alumina, and 30 parts deionized water.

[0047] The structure-directing agent is composed of an asymmetric Gemini quaternary ammonium salt surfactant and a chitosan polycationic surfactant in a 1:1 mass ratio.

[0048] Among them, the asymmetric Gemini quaternary ammonium salt surfactant is prepared from cocoylpropyl dimethyl tertiary amine, dodecylpropyl dimethyl tertiary amine and epichlorohydrin.

[0049] The chitosan polycationic surfactant is 6-aminoethylamino-6-deoxy-N,N,N-trimethylchitosan quaternary ammonium salt.

[0050] The catalyst support is activated carbon, with a specific surface area of ​​850 m². 2 / g, pore volume 0.8m 3 / g, average pore size 20nm.

[0051] The active components consist of phosphomolybdic acid, ZrOCl2·8H2O, CeCl3·7H2O and 50% Mn(NO3)2 aqueous solution in a mass ratio of 1:10:10:10.

[0052] The preparation method of the above-mentioned desulfurization catalyst proposed in this invention comprises the following steps:

[0053] S1: Thoroughly mix the catalyst support, active components, and deionized water to obtain mixture A;

[0054] S2: Add structure-directing agent and binder to mixture A and mix thoroughly to obtain mixture B;

[0055] S3: The mixture B is dried and calcined to obtain the desulfurization catalyst.

[0056] The drying temperature in S3 is 100℃ for 1 hour; the calcination temperature is 500℃ for 4 hours.

[0057] Comparative Example 1

[0058] The structure-directing agent in this scheme is an asymmetric Gemini quaternary ammonium salt surfactant, wherein the asymmetric Gemini quaternary ammonium salt surfactant is prepared from cocoylpropyl dimethyl tertiary amine, dodecylpropyl dimethyl tertiary amine and epichlorohydrin.

[0059] All other conditions are the same as in Example 1.

[0060] Comparative Example 2

[0061] The structure directing agent in this scheme is 6-aminohexylamino-6-deoxy-N,N,N-trimethylchitosan quaternary ammonium salt.

[0062] All other conditions are the same as in Example 1.

[0063] Comparative Example 3

[0064] The active components of this solution consist of ZrOCl2·8H2O, CeCl3·7H2O and 50% Mn(NO3)2 aqueous solution in a mass ratio of 1:1:1.

[0065] All other conditions are the same as in Example 1.

[0066] Comparative Example 4

[0067] The active components of this solution consist of phosphomolybdic acid, ZrOCl2·8H2O and 50% Mn(NO3)2 aqueous solution in a mass ratio of 1:1:1.

[0068] All other conditions are the same as in Example 1.

[0069] Comparative Example 5

[0070] The active components of this solution consist of phosphomolybdic acid, CeCl3·7H2O and 50% Mn(NO3)2 aqueous solution in a mass ratio of 1:1:1.

[0071] All other conditions are the same as in Example 1.

[0072] Comparative Example 6

[0073] The active components of this solution consist of phosphomolybdic acid, ZrOCl2·8H2O and CeCl3·7H2O in a mass ratio of 1:1:1.

[0074] All other conditions are the same as in Example 1.

[0075] The dehydrosulfurization performance of the catalysts prepared in Example 1 and Comparative Examples 1-6 was tested, and the results are shown in Table 1. Wherein:

[0076] The test method for the dehydrosulfurization performance of the catalyst is as follows: volume hourly space velocity (VHSV) of 2000 h⁻¹ - The reaction pressure was 0.2 MPa, and the hydrogen sulfide content was 500 mg / Nm³. 3 The desulfurization reaction temperature is 60℃.

[0077] Table 1. Hydrogen sulfide removal performance test of the catalyst

[0078] Example 1 99.5 Comparative Example 1 91.6 Comparative Example 2 88.3 Comparative Example 3 80.9 Comparative Example 4 86.1 Comparative Example 5 87.2 Comparative Example 6 68.4

[0079] As can be seen from the experimental results of Example 1 in Table 1, during the calcination of the mixture of the present invention, the active components are fully attached to the surface of activated carbon due to the effect of the structure directing agent, and the specific surface area of ​​the catalyst is larger, thus giving the catalyst excellent hydrogen sulfide removal performance. As can be seen from the experimental results of Example 1 and Comparative Examples 1 and 2, the structure directing agent of the present invention, composed of an asymmetric Gemini quaternary ammonium salt surfactant and a chitosan polycationic surfactant, has a synergistic promoting effect on improving the hydrogen sulfide removal performance of the catalyst. As can be seen from the experimental results of Example 1 and Comparative Examples 3, 4, and 5, when the active component does not contain phosphomolybdic acid, the hydrogen sulfide removal rate decreases significantly. This is because phosphomolybdic acid acts as both an acidic medium and a... The catalyst can also serve as a catalytic active site. The decrease in hydrogen sulfide removal rates observed in Comparative Examples 3, 4, and 5 indicates that the active components phosphomolybdic acid, ZrOCl2·8H2O, and CeCl3·7H2O have a synergistic promoting effect on improving the hydrogen sulfide removal performance of the catalyst, thereby further enhancing its performance. The experimental results of Examples 1 and 6 show that the addition of manganese nitrate, combined with the action of other active components, enables the catalyst to achieve highly efficient hydrogen sulfide removal at 60°C. However, when manganese nitrate is not added, the catalyst performance decreases significantly because the catalyst without manganese nitrate operates at a higher temperature and has lower catalytic activity at 60°C.

Claims

1. A hydrogen sulfide removal catalyst characterized by, The raw materials include the following parts by weight: 80-120 parts catalyst support, 1-10 parts active component, 1-5 parts structure directing agent, 1-5 parts binder and 10-30 parts deionized water; The structure-directing agent is composed of an asymmetric Gemini quaternary ammonium salt surfactant and a chitosan polycationic surfactant in a mass ratio of 4:1-4; The asymmetric Gemini quaternary ammonium salt surfactant was prepared from cocoylpropyl dimethyl tertiary amine, dodecylpropyl dimethyl tertiary amine and epichlorohydrin. The chitosan polycationic surfactant is one or more of 6-O-p-toluenesulfonyl-N,N,N-trimethyl chitosan quaternary ammonium salt, 6-aminohexylamino-6-deoxy-N,N,N-trimethyl chitosan quaternary ammonium salt and 6-aminoethylamino-6-deoxy-N,N,N-trimethyl chitosan quaternary ammonium salt. The active component is composed of phosphomolybdic acid, ZrOCl2·8H2O, CeCl3·7H2O and 50% Mn(NO3)2 aqueous solution in a mass ratio of 1:0.1-10:0.1-10:0.1-10.

2. The desulfurization catalyst according to claim 1, characterized in that, The catalyst carrier is activated carbon having a specific surface area of 700-1000 m 2 / g, a pore volume of 0.5-1 m 3 / g, and an average pore diameter of 10-30 nm.

3. The desulfurization catalyst according to claim 1, characterized in that, The binder is one or more of sodium carboxymethyl cellulose, sodium stearate, polyethylene oxide, hydrated aluminum oxide, hydrated silica, and diatomaceous earth.

4. The method for preparing the desulfurization catalyst according to any one of claims 1-3, characterized in that, The steps are as follows: S1: Thoroughly mix the catalyst support, active components, and deionized water to obtain mixture A; S2: Add structure-directing agent and binder to mixture A and mix thoroughly to obtain mixture B; S3: The mixture B is dried and calcined to obtain the desulfurization catalyst.

5. The method for preparing the desulfurization catalyst according to claim 4, characterized in that, The drying temperature in S3 is 80-100℃, and the time is 1-3 hours; the calcination temperature is 300-500℃, and the time is 4-8 hours.

6. The use of the desulfurization catalyst as described in any one of claims 1-3 in the removal of hydrogen sulfide from gases.