A mesoporous zinc oxide desulfurizer and its application in efficient desulfurization of coke oven gas

Abstract

The present invention relates to the field of desulfurization technology, and provides a mesoporous zinc oxide desulfurizer and its coke oven gas efficient desulfurization application. The preparation method comprises the following steps: first dissolving a polystyrene-block-polyethylene oxide copolymer in a mixed solvent of toluene and 1-butanol, and adding concentrated hydrochloric acid to form a uniform solution; then dropping zinc isopropoxide into the solution and stirring it thoroughly until the solution is transparent, triggering an evaporation-induced self-assembly process by solvent volatilization to form an ordered mesoporous composite material; finally, placing the composite material in a plasma-enhanced chemical vapor deposition system, and using thermal activation and oxygen plasma collaborative processing technology under a vacuum environment to simultaneously complete the polymer template removal and metal oxide crystallization process to obtain a mesoporous zinc oxide product. This preparation method avoids the drawbacks of traditional high-temperature calcination processes and achieves efficient synthesis under low-temperature conditions. The product exhibits excellent hydrogen sulfide removal ability and good structural stability in coke oven gas desulfurization applications.

Description

Technical Field

[0001] The present invention relates to the technical field of desulfurization, and more particularly to a mesoporous zinc oxide desulfurizer and its application in high-efficiency desulfurization of coke oven gas. Background Art

[0002] The deep removal of sulfides, including hydrogen sulfide (H2S), carbon oxysulfide (COS), and organic sulfur, from coke oven gas (COG) is a key bottleneck in its resource utilization. High-value utilization requires a hydrogen sulfide concentration of no more than 0.1 ppm. Zinc oxide desulfurizers are widely used in this field due to their high reactivity. However, conventional zinc oxide desulfurizers face multiple technical difficulties in efficiently desulfurizing complex COG systems. First, conventional zinc oxide, prepared by traditional high-temperature calcination at temperatures exceeding 500°C, typically has a specific surface area below 50 m² / g. During the desulfurization process, the volume expansion of zinc sulfide easily leads to pore collapse, resulting in a rapid decline in sulfur capacity, with industrial sulfur capacity typically below 20%. Second, the synthesis of mesoporous zinc oxide, developed to address this issue, presents a dilemma: while solvent extraction preserves the mesoporous structure, residual templates reduce the specific surface area by approximately 30%. While the one-step calcination method simplifies the process, the high-temperature thermal stress also causes mesopore collapse, reducing sulfur diffusion efficiency by up to 40%.

[0003] Therefore, despite recent technological improvements, performance bottlenecks have yet to be overcome. There is an urgent need to develop a zinc oxide desulfurizer that simultaneously achieves a high sulfur capacity greater than 35%, resists poisoning, and maintains structural stability at low temperatures, while also avoiding the risks of high-temperature damage and template residue. Summary of the Invention

[0004] To overcome the aforementioned shortcomings of the prior art, the present invention provides a mesoporous zinc oxide desulfurizer and its application in the efficient desulfurization of coke oven gas. This method utilizes a polymer template evaporation-induced self-assembly coupled with thermal activation-plasma synergistic processing technology. Through low-temperature thermal activation at 150-200°C combined with oxygen plasma treatment, template removal and crystallization are achieved in a single step. This overcomes the existing challenges of high-temperature calcination, which results in thermal stress-induced mesoporous structure collapse and low specific surface area during template removal. The resulting mesoporous zinc oxide exhibits a high sulfur capacity, meeting the requirements for high-value utilization of coke oven gas.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A mesoporous zinc oxide desulfurizer is prepared by a method comprising the following steps:

[0007] Step 1: dissolving a polystyrene-block-polyethylene oxide copolymer in a mixed solvent comprising toluene and 1-butanol, adding concentrated hydrochloric acid, and stirring uniformly to obtain a template solution;

[0008] Step 2: adding zinc isopropoxide dropwise to the template solution, stirring until the solution becomes transparent, and then evaporating the mixed solvent to perform evaporation-induced self-assembly to form a mesoporous composite material;

[0009] Step three, loading the mesoporous composite material into a plasma enhanced chemical vapor deposition system, and simultaneously performing thermal activation and oxygen plasma treatment under vacuum conditions to remove the polystyrene-block-polyethylene oxide copolymer and achieve metal oxide crystallization to obtain the mesoporous zinc oxide desulfurizer.

[0010] As a further solution of the present invention, the thermal activation temperature in step three is 150-200° C., the oxygen pressure of the oxygen plasma treatment is 100 mTorr, and the treatment time is 30-50 minutes.

[0011] As a further embodiment of the present invention, in the polystyrene-block-polyethylene oxide copolymer in step 1, the molecular weight of polystyrene is 19,000 g / mol, the molecular weight of polyethylene oxide is 6,500 g / mol, and the dispersion index is 1.09.

[0012] As a further embodiment of the present invention, the mass ratio of toluene to 1-butanol in the mixed solvent in step 1 is 70:30.

[0013] As a further embodiment of the present invention, the mass ratio of the polystyrene-block-polyethylene oxide copolymer to the mixed solvent in step 1 is 1:10.

[0014] As a further embodiment of the present invention, in step 2, the mass ratio of zinc isopropoxide to the mixed solvent is 1:20.

[0015] As a further solution of the present invention, the solvent evaporation in step 2 is carried out at 100° C. for 48 hours to completely evaporate the solvent and form a mesostructured composite material.

[0016] As a further solution of the present invention, the vacuum degree in step three is evacuated to below 0.1 mTorr.

[0017] As a further embodiment of the present invention, the concentration of the concentrated hydrochloric acid is 37%.

[0018] As a further solution of the present invention, a mesoporous zinc oxide desulfurizer is used in the desulfurization of coke oven gas. The use conditions of the mesoporous zinc oxide desulfurizer are: temperature conditions are 200-300 ° C, volume space velocity is 500-1500h -1 .

[0019] Compared with the prior art, the beneficial effects of the mesoporous zinc oxide desulfurizer and its application in efficient desulfurization of coke oven gas of the present invention are:

[0020] The present invention significantly improves the sulfur capacity performance. When the desulfurization temperature is 200-300℃ and the air velocity is 500-1500h -1 Under coke oven gas conditions, the desulfurizer prepared by this invention can achieve a sulfur capacity of 40%, a 100% improvement compared to the conventional zinc oxide desulfurizer, which has a sulfur capacity of no more than 20%. This performance ensures that the high-value utilization requirement of the outlet H2S concentration of ≤0.1ppm is met when the H2S concentration in the imported feed gas is no more than 1000ppm.

[0021] The present invention optimizes the synthesis process. Using low-temperature thermal activation at 150-200°C, combined with oxygen plasma treatment at an oxygen pressure of 100 mTorr for 30-60 minutes, it achieves a one-step process for template removal and oxide crystallization, effectively avoiding problems such as pore collapse and template residue caused by traditional high-temperature treatments.

[0022] This invention enhances the structural stability of the material. The prepared desulfurizer has a three-dimensional ordered mesoporous structure with a pore size of 2-8 nm. This structure, in synergy with the nanoparticles, effectively buffers the volume expansion of ZnS during the reaction. As a result, the desulfurizer maintains a sulfur capacity retention rate of over 95% after five regeneration cycles, demonstrating excellent cyclic stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The present invention is a schematic flow chart of a method for preparing a mesoporous zinc oxide desulfurizer. DETAILED DESCRIPTION

[0024] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0025] A mesoporous zinc oxide desulfurizer is prepared by a method comprising the following steps:

[0026] Step 1: dissolving a polystyrene-block-polyethylene oxide copolymer in a mixed solvent comprising toluene and 1-butanol, adding 37% concentrated hydrochloric acid, and stirring uniformly to obtain a template solution;

[0027] Step 2: adding zinc isopropoxide dropwise to the template solution, stirring until the solution becomes transparent, and then evaporating the mixed solvent to perform evaporation-induced self-assembly to form a mesoporous composite material;

[0028] Step three, loading the mesoporous composite material into a plasma enhanced chemical vapor deposition system, and simultaneously performing thermal activation and oxygen plasma treatment under vacuum conditions to remove the polystyrene-block-polyethylene oxide copolymer and achieve metal oxide crystallization to obtain the mesoporous zinc oxide desulfurizer.

[0029] Example 1

[0030] A method for preparing a mesoporous zinc oxide desulfurizer, the specific steps of which are as follows:

[0031] Step 1: dissolve 100 mg of polystyrene-block-polyethylene oxide copolymer in 1 g of a mixed solvent of toluene and 1-butanol, wherein the mass ratio of toluene to 1-butanol in the mixed solvent is 70:30.

[0032] Step 2: Add 10 μL of 37% concentrated hydrochloric acid to the solution obtained in step 1 and stir evenly.

[0033] Step 3: Add 50 mg of zinc isopropoxide dropwise to the solution treated in step 2, and stir until the solution becomes transparent.

[0034] Step 4: Place the transparent solution obtained in step 3 in an oven at 100° C. for 48 hours for drying to completely evaporate the solvent, thereby forming a mesostructured composite material.

[0035] Step 5: Load the mesostructured composite material obtained in step 4 into a plasma enhanced chemical vapor deposition system, reduce the vacuum degree inside the system to below 0.1 mTorr, and control the heating temperature at 150°C.

[0036] Step six: inject oxygen into the system to generate plasma, while controlling the oxygen pressure in the system at 100 mTorr.

[0037] Step seven: Under the conditions of step six, plasma treatment is performed for 30 minutes. After the treatment is completed, a mesoporous zinc oxide desulfurizer for efficient desulfurization of coke oven gas is finally obtained.

[0038] Example 2

[0039] A method for preparing a mesoporous zinc oxide desulfurizer, the specific steps of which are as follows:

[0040] Step 1: dissolve 100 mg of polystyrene-block-polyethylene oxide copolymer in 1 g of a mixed solvent of toluene and 1-butanol, wherein the mass ratio of toluene to 1-butanol in the mixed solvent is 70:30.

[0041] Step 2: Add 10 μL of 37% concentrated hydrochloric acid to the solution obtained in step 1 and stir evenly.

[0042] Step 3: Add 50 mg of zinc isopropoxide dropwise to the solution treated in step 2, and stir until the solution becomes transparent.

[0043] Step 4: Place the transparent solution obtained in step 3 in an oven at 100° C. for 48 hours for drying to completely evaporate the solvent, thereby forming a mesostructured composite material.

[0044] Step 5: Load the mesostructured composite material obtained in step 4 into a plasma enhanced chemical vapor deposition system, reduce the vacuum degree inside the system to below 0.1 mTorr, and control the heating temperature at 200°C.

[0045] Step six: inject oxygen into the system to generate plasma, while controlling the oxygen pressure in the system at 100 mTorr.

[0046] Step seven: Under the conditions of step six, plasma treatment is performed for 30 minutes. After the treatment is completed, a mesoporous zinc oxide desulfurizer for efficient desulfurization of coke oven gas is finally obtained.

[0047] Example 3

[0048] A method for preparing a mesoporous zinc oxide desulfurizer, the specific steps of which are as follows:

[0049] Step 1: dissolve 100 mg of polystyrene-block-polyethylene oxide copolymer in 1 g of a mixed solvent of toluene and 1-butanol, wherein the mass ratio of toluene to 1-butanol in the mixed solvent is 70:30.

[0050] Step 2: Add 10 μL of 37% concentrated hydrochloric acid to the solution obtained in step 1 and stir evenly.

[0051] Step 3: Add 50 mg of zinc isopropoxide dropwise to the solution treated in step 2, and stir until the solution becomes transparent.

[0052] Step 4: Place the transparent solution obtained in step 3 in an oven at 100° C. for 48 hours for drying to completely evaporate the solvent, thereby forming a mesostructured composite material.

[0053] Step 5: Load the mesostructured composite material obtained in step 4 into a plasma enhanced chemical vapor deposition system, reduce the vacuum degree inside the system to below 0.1 mTorr, and control the heating temperature at 200°C.

[0054] Step six: inject oxygen into the system to generate plasma, while controlling the oxygen pressure in the system at 100 mTorr.

[0055] Step seven: Under the conditions of step six, plasma treatment is performed for 40 minutes. After the treatment is completed, a mesoporous zinc oxide desulfurizer for efficient desulfurization of coke oven gas is finally obtained.

[0056] Example 4

[0057] A method for preparing a mesoporous zinc oxide desulfurizer, the specific steps of which are as follows:

[0058] Step 1: dissolve 100 mg of polystyrene-block-polyethylene oxide copolymer in 1 g of a mixed solvent of toluene and 1-butanol, wherein the mass ratio of toluene to 1-butanol in the mixed solvent is 70:30.

[0059] Step 2: Add 10 μL of 37% concentrated hydrochloric acid to the solution obtained in step 1 and stir evenly.

[0060] Step 3: Add 50 mg of zinc isopropoxide dropwise to the solution treated in step 2, and stir until the solution becomes transparent.

[0061] Step 4: Place the transparent solution obtained in step 3 in an oven at 100° C. for 48 hours for drying to completely evaporate the solvent, thereby forming a mesostructured composite material.

[0062] Step 5: Load the mesostructured composite material obtained in step 4 into a plasma enhanced chemical vapor deposition system, reduce the vacuum degree inside the system to below 0.1 mTorr, and control the heating temperature at 200°C.

[0063] Step six: inject oxygen into the system to generate plasma, while controlling the oxygen pressure in the system at 100 mTorr.

[0064] Step seven: Under the conditions of step six, plasma treatment is performed for 50 minutes. After the treatment is completed, a mesoporous zinc oxide desulfurizer for efficient desulfurization of coke oven gas is finally obtained.

[0065] Example 5

[0066] In order to verify the performance of the mesoporous zinc oxide desulfurizer prepared in Examples 1-4, the following desulfurization performance test was conducted in the examples of the present invention.

[0067] The zinc oxide desulfurizer samples prepared in Examples 1-4 were compressed into cylindrical pellets with a diameter of 4 mm and a height of 4 mm. Each pellet was placed in a fixed-bed reactor, and simulated coke oven gas (composition: 65% H2, 4.5% N2, 5.5% CO, 2% CO2, 23% CH4) was introduced into the reactor. The H2S concentration in the simulated gas was 200 ppm. The test conditions were set at a volume space velocity of 1500 h / min. -1 , reaction temperature 250 ° C. The sulfur capacity of each sample was analyzed and calculated according to standard HG / T2513-2014, and the test results are recorded in Table 1.

[0068] Table 1 - Test results of mesoporous zinc oxide desulfurizer

[0069]

[0070] The test results in Table 1 show that, under the condition of outlet H2S ≤ 0.1 ppm, the mesoporous zinc oxide desulfurizers prepared in Examples 1-4 all exhibited high sulfur capacity. Specifically, the samples prepared in Examples 3 and 4 achieved a sulfur capacity of 40.5%. This data confirms that when the thermal activation temperature is controlled at 200°C and the treatment time is 40 to 50 minutes, the prepared desulfurizers exhibit particularly excellent desulfurization performance. This fully demonstrates that the technical solution provided by the present invention can effectively solve the problems encountered in existing technologies and has outstanding advantages in the application of efficient coke oven gas desulfurization.

[0071] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

[0072] Finally: The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A mesoporous zinc oxide desulfurizer, characterized in that: The mesoporous zinc oxide desulfurizer is prepared by a method comprising the following steps: Step 1: dissolving a polystyrene-block-polyethylene oxide copolymer in a mixed solvent comprising toluene and 1-butanol, adding concentrated hydrochloric acid, and stirring uniformly to obtain a template solution; Step 2: adding zinc isopropoxide dropwise to the template solution, stirring until the solution becomes transparent, and then evaporating the mixed solvent to perform evaporation-induced self-assembly to form a mesoporous composite material; Step 3: Loading the mesoporous composite material into a plasma-enhanced chemical vapor deposition system, and simultaneously performing thermal activation and oxygen plasma treatment under vacuum conditions to remove the polystyrene-block-polyethylene oxide copolymer and achieve metal oxide crystallization to obtain the mesoporous zinc oxide desulfurizer; The thermal activation temperature in step 3 is 150-200° C., the oxygen pressure of the oxygen plasma treatment is 100 mTorr, and the treatment time is 30-50 minutes.

2. A mesoporous zinc oxide desulfurizer according to claim 1, characterized in that: In the polystyrene-block-polyethylene oxide copolymer described in step 1, the molecular weight of polystyrene is 19000 g / mol, the molecular weight of polyethylene oxide is 6500 g / mol, and the dispersion index is 1.

09.

3. A mesoporous zinc oxide desulfurizer according to claim 1, characterized in that: The mass ratio of toluene and 1-butanol in the mixed solvent in step 1 is 70:

30.

4. A mesoporous zinc oxide desulfurizer according to claim 1, characterized in that: The mass ratio of the polystyrene-block-polyethylene oxide copolymer to the mixed solvent in step 1 is 1:

10.

5. A mesoporous zinc oxide desulfurizer according to claim 1, characterized in that: In step 2, the mass ratio of zinc isopropoxide to the mixed solvent is 1:

20.

6. A mesoporous zinc oxide desulfurizer according to claim 1, characterized in that: In step 2, the solvent was evaporated at 100° C. for 48 hours.

7. The mesoporous zinc oxide desulfurizer according to claim 1, characterized in that: In step 3, the vacuum degree is reduced to below 0.1 mTorr.

8. The mesoporous zinc oxide desulfurizer according to claim 1, characterized in that: The concentration of the concentrated hydrochloric acid is 37%.

9. Use of the mesoporous zinc oxide desulfurizer according to any one of claims 1 to 8 in desulfurization of coke oven gas, characterized in that: The operating conditions of the mesoporous zinc oxide desulfurizer are: temperature condition is 200-300℃, and volume space velocity is 500-1500h⁻¹.

Images