A medium and high temperature desulfurization composite adsorbent, its preparation method and application

Abstract

The present invention discloses a medium and high temperature desulfurization composite adsorbent and its preparation method and application. The composite adsorbent uses rectorite or modified rectorite as a carrier and metal oxides loaded on the carrier as active ingredients. The preparation method of the sulfur composite adsorbent is as follows: S1. Add nitric acid solution to the nitrate solution to adjust the pH, and then add citric acid, and mix evenly to obtain a mixed solution; S2. Add rectorite or modified rectorite to the mixed solution, and then perform ultrasonic impregnation treatment. The impregnated rectorite or modified rectorite is subjected to a water bath. After it becomes a gel state, it is aged. After the aging is completed, it is dried to obtain a solid; S3. Place the solid in a muffle furnace for calcination, and after the calcination is completed, it is crushed. This composite adsorbent has high desulfurization efficiency, good cycle stability, and is easy to regenerate, and can be used for high-temperature removal of hydrogen sulfide gas generated in integrated gasification combined cycle power generation, fuel cell production, and biomass gasification power generation processes.

Description

Technical Field

[0001] The present invention belongs to the technical field of desulfurization adsorbents, and particularly relates to a medium and high temperature desulfurization composite adsorbent, a preparation method thereof and an application thereof. Background Art

[0002] Integrated gasification combined cycle power generation technology is an advanced power system that combines gasification technology and an efficient combined cycle. It can not only improve the energy conversion efficiency of traditional power generation technology, but also reduce the environmental pollution caused by gaseous pollutants. Solid fuel cell technology and biomass gasification power generation technology can not only solve the effective utilization of renewable energy, but also solve the environmental pollution of various organic waste. However, the gas generated in the three technical processes contains a certain mass of hydrogen sulfide, which will corrode downstream equipment and pollute the environment. Therefore, the removal of hydrogen sulfide in the process is particularly important. At present, the most commonly used desulfurization method is wet desulfurization, such as low-temperature methanol washing and other means, but wet desulfurization is generally carried out in a low-temperature environment. Since the temperature of the gasified coal gas is generally above 800 degrees, wet desulfurization needs to pass through a heat exchanger to reduce the temperature to a low temperature for desulfurization before desulfurization, and then pass through a heat exchanger to raise the temperature to the gas temperature required for subsequent processes. The rise and fall of the temperature will reduce the energy consumption of the process and cause waste of energy. Moreover, wet desulfurization will also waste water resources. High-temperature desulfurization is generally carried out in a medium and high temperature environment, which can not only save heat exchange equipment, but also improve the energy utilization rate of the process because the temperature rise and fall links are omitted.

[0003] Medium and high temperature dry desulfurization mainly uses renewable desulfurization adsorbents (single or composite metal oxides) to react with hydrogen sulfide to form metal sulfides and water to complete. In the past few decades, researchers have carried out a large number of studies on high-temperature dry desulfurization and the performance of desulfurization agents, aiming to develop efficient and high-performance desulfurization adsorbents. Although there have been many studies on the preparation of high-temperature coal gas desulfurization agents and their desulfurization mechanisms, there are still some problems:

[0004] When using a carrier to load active components to prepare a supported medium and high temperature desulfurization adsorbent, on the one hand, it can promote the diffusion of gas and the utilization of metal oxide active components, and on the other hand, it can significantly increase the mechanical strength of the desulfurization adsorbent, reduce the wear of the desulfurization adsorbent during the desulfurization-regeneration process, and significantly improve the performance of the desulfurization adsorbent. However, the desulfurization adsorbent needs to be recycled repeatedly in actual application. According to the desulfurization-regeneration reaction characteristics, during the cycle, oxygen and sulfur ions are repeatedly replaced. Due to the different radii of oxygen and sulfur ions, the volume of the desulfurization adsorbent expands and contracts repeatedly, which easily causes the carrier structure of the desulfurization adsorbent to break and collapse. The destruction of the pore structure of the desulfurization adsorbent may lead to the loss of some active components.

[0005] Therefore, how to overcome the damage to the carrier structure caused by the volume expansion and contraction of the desulfurization adsorbent during the desulfurization-regeneration cycle, so that the reaction activity, sulfur capacity, mechanical properties, etc. of the medium and high temperature desulfurization adsorbent remain stable during multiple consecutive desulfurization-regeneration processes, is still a key problem that must be solved for the ultimate efficient application of high temperature desulfurization adsorbents. Summary of the Invention

[0006] Based on the above background technology, the present invention provides a medium and high temperature desulfurization composite adsorbent, its preparation method and application. This composite adsorbent has high desulfurization efficiency, good cycle stability, easy regeneration during the desulfurization-regeneration cycle, and its preparation method is simple. It can be used for high temperature removal of hydrogen sulfide gas generated in the processes of integrated gasification combined cycle power generation (IGCC), fuel cell production, and biomass gasification power generation (BGPG).

[0007] The technical solution adopted to achieve the above object of the present invention is as follows:

[0008] A preparation method of a medium and high temperature hydrogen sulfide removal composite adsorbent, wherein the composite adsorbent uses rectorite or modified rectorite as the carrier, and metal oxide loaded on the carrier as the active ingredient. The content of the carrier is 50-98 wt%, and the content of the metal oxide is 2-50 wt%.

[0009] Further, the metal in the metal oxide is selected from at least one of manganese, iron, copper, zinc, lanthanum, cerium, barium, and nickel.

[0010] A preparation method of a medium and high temperature desulfurization composite adsorbent, comprising the following steps:

[0011] S1. Add nitric acid solution to the nitrate solution, adjust the pH value to 1-5, and then add citric acid, and mix evenly to obtain a mixed solution;

[0012] S2. Add rectorite or modified rectorite to the mixed solution, and then perform ultrasonic impregnation treatment. The impregnated rectorite or modified rectorite is subjected to a water bath. After it becomes a gel state, it is aged. After aging is completed, it is dried to obtain a solid;

[0013] S3. Place the solid in a muffle furnace for calcination. After calcination is completed, it is crushed to obtain the medium and high temperature desulfurization composite adsorbent.

[0014] Further, the concentration of the nitrate is 0.5-2 mol / L, and the addition amount of citric acid is 1-3 times the molar mass of the metal ions in the nitrate.

[0015] Further, the nitrate is selected from at least one of manganese nitrate, iron nitrate, copper nitrate, zinc nitrate, lanthanum nitrate, cerium nitrate, barium nitrate, and nickel nitrate.

[0016] Furthermore, the time for the ultrasonic impregnation treatment is 5 - 60 min, the water bath temperature is 40 - 90 °C, the aging temperature is room temperature, and the aging time is 1 - 7 days.

[0017] Furthermore, the calcination temperature is 400 - 900 °C, and the calcination time is 4 - 9 h.

[0018] Application of a medium and high temperature desulfurization composite adsorbent in high temperature removal of hydrogen sulfide in integrated gasification combined cycle power generation, solid fuel cell production, and biomass gasification power generation processes.

[0019] Furthermore, the temperature for hydrogen sulfide removal is 500 - 900 °C.

[0020] Compared with the prior art, the beneficial effects and advantages of the present invention are as follows:

[0021] 1. The rectorite of the present invention is a 1:1 regular interstratified mineral composed of dioctahedral mica layers and dioctahedral montmorillonite layers. As a desulfurizer carrier, its mica layer structure can significantly improve the thermal stability and mechanical properties of the desulfurizer.

[0022] 2. The present invention uses rectorite as a carrier, and the active components are loaded on the surface and between the layers of the rectorite. The interlayer structure of the montmorillonite layer in the rectorite can be regulated, and the presence of the montmorillonite layer is expected to weaken the effect of the repeated volume expansion and contraction caused by the repeated replacement of S and O ions on the mica layer structure, maintaining the stability of the framework structure. Therefore, the layered structure of rectorite is expected to reduce the risk of structural fracture of the desulfurizer during the desulfurization - regeneration cycle.

[0023] 3. The carrier rectorite of the present invention is an environmentally friendly natural mineral with a relatively low price. As a carrier, it can reduce the consumption of chemical reagents and environmental pollution caused by reagent evaporation brought about by chemically synthesized carriers (such as mesoporous silica, molecular sieves, etc.).

[0024] 4. The composite adsorbent of the present invention is in a dry state and does not require an aqueous solution during use, reducing water consumption.

[0025] 5. The composite adsorbent of the present invention has a hydrogen sulfide removal rate higher than 95% at high temperatures, good cycle stability, and easy regeneration, meeting the requirements of various hydrogen sulfide removal working conditions and having a wide range of uses. Description of the Drawings

[0026] Figure 1 Desulfurization curve of the medium and high temperature desulfurization composite adsorbent prepared in Example 1 during the desulfurization - regeneration cycle.

[0027] Figure 2 Breakthrough sulfur capacity diagram of the medium and high temperature desulfurization composite adsorbent prepared in Example 1 during the desulfurization - regeneration cycle.

[0028] Figure 3 Desulfurization curve of the medium and high temperature desulfurization composite adsorbent prepared in Example 2 during the desulfurization regeneration cycle.

[0029] Figure 4 Breakthrough sulfur capacity diagram of the medium and high temperature desulfurization composite adsorbent prepared in Example 2 during the desulfurization regeneration cycle.

[0030] Figure 5 Desulfurization curve of the medium and high temperature desulfurization composite adsorbent prepared in Example 3 during the desulfurization regeneration cycle.

[0031] Figure 6 Breakthrough sulfur capacity diagram of the medium and high temperature desulfurization composite adsorbent prepared in Example 3 during the desulfurization regeneration cycle.

[0032] Figure 7 Pore size distribution curve of the medium and high temperature desulfurization composite adsorbent prepared in Examples 1-3.

[0033] Figure 8 XRD pattern of the medium and high temperature desulfurization composite adsorbent prepared in Examples 1-3. Detailed implementation mode

[0034] The present invention will be described in detail below with reference to specific embodiments. The embodiments cited are only used to explain the present invention and are not intended to limit the scope of the present invention.

[0035] Example 1

[0036] S1. Add 1 ml of 6 mol / L nitric acid solution to 10 ml of 2 mol / L manganese nitrate solution, adjust the pH value to 2, and then add 5.043 g of citric acid monohydrate, and mix evenly to obtain a mixed solution.

[0037] S2. Take 3.0 g of rectorite powder and slowly add it to the mixed solution, then ultrasonicate for 30 minutes to ensure sufficient impregnation. Place the impregnated rectorite in a water bath at 60 °C and stir. After it becomes a gel state, age it at room temperature for 3 days and then dry it to obtain a solid.

[0038] S3. Place the solid in a muffle furnace and calcine it at 650 °C for 9 h. After the calcination is completed, let it cool naturally to room temperature, and then grind it. Screen out the powder with a mesh size of 20-40 to obtain the medium and high temperature desulfurization composite adsorbent (the content of manganese oxide is 42.22%, and the content of rectorite is 57.88%), denoted as composite adsorbent I.

[0039] Example 2

[0040] S1. Take 3.0 g of rectorite, add it to 500 ml of distilled water, ultrasonically treat it for 30 min, and then place it in a constant temperature water bath at 70 °C and stir for 1 h. After stirring is completed, add 100 ml of 1 mol·L-1 The HCl solution was added, and the mixture was stirred evenly to obtain a rectorite suspension.

[0041] S2. The rectorite suspension was continuously stirred in a 70 °C constant temperature water bath for 8 h. After stirring, it was filtered, and the filter cake was washed repeatedly with distilled water until no Cl - existed. The washed filter cake was placed in a drying oven at 110 °C and dried for 10 h. After drying, solid A was obtained. Solid A was placed in a muffle furnace, heated to 500 °C, and the heating rate was controlled at 5 °C·min -1 . It was calcined at 500 °C for 3 h to obtain acidified rectorite.

[0042] S3. 25 ml of 0.5 mol / L manganese nitrate solution and 8 ml of 10 wt% zinc nitrate solution were mixed to obtain a nitrate solution.

[0043] S4. 0.5 ml of 6 mol·L -1 nitric acid solution was added to the nitrate solution to adjust the pH value to 3. Then, 7.9 g of citric acid monohydrate was added, and the mixture was stirred evenly to obtain a mixed solution.

[0044] S5. 3.0 g of acidified rectorite powder was slowly added to the mixed solution, and then ultrasonic treatment was carried out for 60 minutes to ensure sufficient impregnation. The impregnated rectorite was stirred in a 40 °C water bath. After it became a gel state, it was aged at room temperature for 7 days and then dried to obtain solid B.

[0045] S6. Solid B was placed in a muffle furnace and calcined at 500 °C for 6 h. After calcination, it was naturally cooled to room temperature, then ground, and the powder with a mesh size of 20 - 40 was sieved out to obtain the medium and high temperature desulfurization composite adsorbent (the content of oxygen oxides was 33.88%, the content of zinc oxide was 0.75%, and the content of rectorite was 65.37%), denoted as composite adsorbent II.

[0046] Example 3

[0047] S1. 3.0 g of rectorite was taken, added to 500 ml of distilled water, ultrasonically treated for 30 min, and then stirred in a 70 °C constant temperature water bath for 1 h. After stirring, 100 ml of 1 mol·L -1 HCl solution was added, and the mixture was stirred evenly to obtain a rectorite suspension.

[0048] S2. At room temperature, 10 ml of tetrabutyl titanate was added dropwise to 30 ml of absolute ethanol, and the mixture was stirred for 30 min to obtain a mixed solution A.

[0049] S3. At room temperature, 3.0 ml of distilled water, 30 ml of absolute ethanol, and 3.0 ml of glacial acetic acid were mixed. After mixing evenly, 5 drops of 8 mol / L HNO3 were added dropwise and stirred evenly to obtain a mixed solution B.

[0050] S4. Add the mixed solution B to the mixed solution A at a rate of 60 ml·h -1 . Stir and mix evenly to obtain a mixed solution C. Add the mixed solution C dropwise into the rectorite suspension. After the addition is completed, continue to stir for 1 h to obtain a white suspension.

[0051] S5. Age the white suspension at room temperature for 16 h, centrifuge and wash it. Place the washed filter cake in a drying oven at 110 °C and dry it for 10 h. After drying is completed, obtain a solid A. Place the solid A in a muffle furnace, heat it up to 500 °C, and control the heating rate at 5 °C·min -1 . Maintain the calcination at 500 °C for 3 h to obtain Ti-modified rectorite.

[0052] S6. Mix 12 ml of 1 mol / L manganese nitrate solution and 0.3 ml of 10 wt% cerium nitrate solution to obtain a nitrate solution.

[0053] S7. Add 2 ml of 6 mol·L -1 nitric acid solution to the nitrate solution, adjust the pH value to 1, and then add 3.5 g of citric acid monohydrate. Mix evenly to obtain a mixed solution.

[0054] S8. Slowly add 3.0 g of Ti-modified rectorite powder to the acidified solution, and then ultrasonicate for 30 minutes to ensure sufficient impregnation. Place the impregnated rectorite in a water bath at 60 °C and stir. After it becomes a gel state, age it at room temperature for 3 days and dry it to obtain a solid.

[0055] S9. Place the solid in a muffle furnace and calcine it at 900 °C for 4 h. After the calcination is completed, let it cool naturally to room temperature, and then grind it. Screen out the powder with a mesh size of 20 - 40 to obtain the medium and high temperature desulfurization composite adsorbent (the content of manganese oxide is 25.18%, the content of cerium oxide is 2.19%, and the content of Ti-modified rectorite is 72.63%), denoted as composite adsorbent III.

[0056] Perform specific surface area testing and pore size analysis on the medium and high temperature desulfurization composite adsorbents prepared in Examples 1 - 3. The obtained results are shown in Table 1 below:

[0057] Table 1 Specific surface area, pore volume and pore size of different desulfurization composite adsorbents

[0058]

[0059] The pore size distribution curves of the medium and high temperature desulfurization composite adsorbents prepared in Examples 1 - 3 are as Figure 7 shown, from Figure 7It can be seen that the pore structure distributions of the composite adsorbents Ⅰ, Ⅱ and Ⅲ obtained by loading with rectorite or modified rectorite are relatively uniform, and the proportions of macropores and mesopores are relatively high, which is conducive to the diffusion of hydrogen sulfide gas during the desulfurization process and is conducive to the composite adsorbent to adsorb and remove hydrogen sulfide.

[0060] The medium- and high-temperature desulfurization composite adsorbents prepared in Examples 1-3 were subjected to X-ray diffraction analysis, and the obtained XRD is as Figure 8 shown. Characteristic diffraction peaks of Mn2O3 (2θ = 23.2°, 32.9°, 38.5°, 55.0°, 66.5°) appeared in the desulfurization composite adsorbents as carriers before and after the modification of rectorite. There were also characteristic diffraction peaks of Mn3O4 (2θ = 20.3°, 30.1°, 38.5°, 60.2°) on the surface of the medium- and high-temperature desulfurization composite adsorbent Ⅰ prepared in Example 1. Thus, it can be seen that the desulfurization composite adsorbent of the present invention uses metal oxides such as Mn2O3 and Mn3O4 as active components to participate in the desulfurization reaction.

[0061] Experiment 1. Desulfurization and regeneration effect experiment of the medium- and high-temperature desulfurization composite adsorbent of the present invention

[0062] Test method:

[0063] The composite adsorbent Ⅰ prepared in Example 1, the composite adsorbent Ⅱ prepared in Example 2, and the composite adsorbent prepared in Example 3 were used to simulate the desulfurization-regeneration effect experiment of coal gasification gas on a laboratory small heating furnace. The test was carried out under normal pressure, and the desulfurization conditions were as follows: Atmosphere condition: 10% H2, 2000 mg / m 3 H2S, with N2 as the balance gas, desulfurization temperature 650 °C, gas space velocity: 12 L·g -1 ·h -1 ; Regeneration conditions: 5% O2, with N2 as the balance gas, regeneration temperature 650 °C, regeneration gas space velocity: 12 L·g -1 ·h -1 . Evaluation index: When the concentration of H2S in the tail gas is higher than 50 mg / m 3 , it is considered that the adsorbent has penetrated, and the H2S adsorbed by the adsorbent within this time becomes the breakthrough sulfur capacity (BSC).

[0064] Test results:

[0065] The desulfurization effect diagram of the composite adsorbent Ⅰ prepared in Example 1 is as Figure 1 and Figure 2 shown. It can be seen from Figure 1 that the composite adsorbent Ⅰ prepared in Example 1 has good desulfurization effect, the removal rate of hydrogen sulfide > 99%, and the hydrogen sulfide content in the tail gas is lower than 50 mg / m 3 ; From Figure 2It can be seen that the composite adsorbent Ⅰ prepared in Example 1 has stable desulfurization performance during the desulfurization-regeneration cycle, and both the breakthrough sulfur capacity and the desulfurization efficiency remain stable. The average content of hydrogen sulfide in the tail gas during the desulfurization-regeneration process is lower than 50 mg / m 3 .

[0066] The desulfurization effect diagram of the composite adsorbent Ⅱ prepared in Example 2 is as shown in Figure 3 and Figure 4 . It can be seen from Figure 3 that the composite adsorbent Ⅱ prepared in Example 2 has good desulfurization effect, the removal rate of hydrogen sulfide > 99%, and the content of hydrogen sulfide in the tail gas is lower than 50 mg / m 3 ; It can be seen from Figure 4 that the composite adsorbent Ⅱ prepared in Example 2 has stable desulfurization performance during the desulfurization-regeneration cycle, and both the breakthrough sulfur capacity and the desulfurization efficiency remain stable. The average content of hydrogen sulfide in the tail gas during the desulfurization-regeneration process is lower than 50 mg / m 3 .

[0067] The desulfurization effect diagram of the composite adsorbent Ⅲ prepared in Example 3 is as shown in Figure 5 and Figure 6 . It can be seen from Figure 5 that the composite adsorbent Ⅲ prepared in Example 3 has good desulfurization effect, the removal rate of hydrogen sulfide > 99%, and the content of hydrogen sulfide in the tail gas is lower than 50 mg / m3; It can be seen from Figure 6 that the composite adsorbent Ⅲ prepared in Example 6 has stable desulfurization performance during the desulfurization-regeneration cycle, and both the breakthrough sulfur capacity and the desulfurization efficiency remain stable. The average content of hydrogen sulfide in the tail gas during the desulfurization-regeneration process is lower than 50 mg / m3.

Claims

1. Application of a medium and high temperature desulfurization composite adsorbent in high temperature removal of hydrogen sulfide in integrated gasification combined cycle power generation, solid fuel cell production and biomass gasification power generation processes, characterized in that: The composite adsorbent uses rectorite or modified rectorite as the carrier and the metal oxide supported on the carrier as the active ingredient. The content of the carrier is 50-98 wt%, and the content of the metal oxide is 2-50 wt%. The metal in the metal oxide is manganese, or one of the metals is a combination of manganese and at least one of iron, copper, zinc, lanthanum, cerium, barium, and nickel.

2. The application of the medium and high temperature desulfurization composite adsorbent according to claim 1, characterized in that: The temperature for hydrogen sulfide removal is 500-900 °C.

3. A preparation method of the medium and high temperature desulfurization composite adsorbent according to claim 1, characterized in that It includes the following steps: S1. Add nitric acid solution to the nitrate solution, adjust the pH value to 1-5, and then add citric acid and mix evenly to obtain a mixed solution. S2. Add rectorite or modified rectorite to the mixed solution, then perform ultrasonic impregnation treatment. The impregnated rectorite or modified rectorite is subjected to a water bath. After it becomes a gel state, it is aged. After the aging is completed, it is dried to obtain a solid. S3. Place the solid in a muffle furnace for calcination. After the calcination is completed, it is crushed to obtain the medium and high temperature desulfurization composite adsorbent.

4. The preparation method of the medium and high temperature desulfurization composite adsorbent according to claim 3, characterized in that: The concentration of the nitrate is 0.5-2 mol / L, and the addition amount of citric acid is 1-3 times the molar mass of the metal ions in the nitrate.

5. The preparation method of the medium and high temperature desulfurization composite adsorbent according to claim 3, characterized in that: The nitrate is manganese nitrate, or one of the nitrates is a combination of manganese nitrate and at least one of iron nitrate, copper nitrate, zinc nitrate, lanthanum nitrate, cerium nitrate, barium nitrate, and nickel nitrate.

6. The preparation method of the medium and high temperature desulfurization composite adsorbent according to claim 3, characterized in that: The time for the ultrasonic impregnation treatment is 5-60 min, the water bath temperature is 40-90 °C, the aging temperature is room temperature, and the aging time is 1-7 days.

7. The preparation method of the medium and high temperature desulfurization composite adsorbent according to claim 3, characterized in that: The calcination temperature is 400-900 °C, and the calcination time is 4-9 h.

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