Biomass-based activated carbon catalyst for synchronously removing COS and H2S in blast furnace gas and preparation method of biomass-based activated carbon catalyst
By modifying biochar materials, using urea and aluminum nitrate to form surface alkaline functional groups and oxygen vacancies, and combining this with high-temperature calcination to form Al2O3 distribution, the problem of sulfur capacity and pore structure matching in the efficient removal of COS and H2S from blast furnace gas by activated carbon materials is solved, achieving efficient and safe desulfurization.
Patent Information
- Application Number
- CN202511607506.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-05
- Publication Date
- 2025-12-23
AI Technical Summary
Existing activated carbon materials have limited sulfur capacity and insufficient matching between pore structure and pollutant molecular dynamics diameter when efficiently removing COS and H2S from blast furnace gas, resulting in poor adsorption stability and room for improvement in overall desulfurization efficiency.
Urea, nitric acid, and potassium hydroxide solution were added to biochar material using a hydrothermal method. By introducing KOH and biochar for modification, surface alkaline functional groups and oxygen vacancies were formed. Combined with high-temperature calcination to form Al2O3 distribution, the synergistic chemical adsorption capacity of COS and H2S was improved.
It significantly improves the removal efficiency of COS and H2S, reduces raw material costs, reduces solid waste pollution, has high operational safety, and achieves efficient desulfurization.
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Figure CN121180992A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application belongs to the field of atmospheric pollution purification materials, and particularly relates to a biomass synchronous removal of blast furnace gas COS and H2S activated carbon catalyst and a preparation method thereof. BACKGROUND
[0002] The steel industry is a pillar industry of China's national economy. In 2017, the amount of industrial waste gas emitted by the steel industry has become the highest among all industries, and is an important source of air pollution in China. With the continuous promotion of ultra-low emission policy, the air pollution control requires that the pollutant emission indicators produced by each production link of the steel industry meet the latest emission standards. The sulfur components of blast furnace gas are mainly carbonyl sulfide (COS) and hydrogen sulfide (H2S), etc., which generate SO2 after secondary combustion by downstream users. However, end-point desulfurization cannot meet the latest emission standards, and the desulfurization process needs to be optimized, source control needs to be strengthened, and blast furnace gas fine desulfurization needs to be implemented, thereby promoting the synergistic effect of pollution reduction and carbon reduction in the steel industry.
[0003] The existing front-end desulfurization methods mainly include photolysis method, absorption method, adsorption method, hydrogenation method and adsorption hydrolysis method. Compared with several COS removal technologies, the photolysis method has many limitations such as light intensity and time, and is only in laboratory research and has not been applied in industry. Although the absorption method has a simple process and a wide source of absorbents, a large amount of waste liquid is generated after the reaction, increasing the difficulty and cost of subsequent treatment. The dry adsorption method has more advantages than the absorption method, and it does not produce waste liquid and has a simple device, but it needs a large amount of adsorbent to treat organic sulfur in large amounts of blast furnace gas, resulting in high cost of adsorbent investment, and the adsorbed adsorbent is also difficult to handle, which is not suitable for fine desulfurization of large amounts of blast furnace gas. The hydrolysis method and the hydrogenation method can both achieve efficient removal of COS, with a removal efficiency of more than 95%. However, the reaction conditions of the hydrogenation method are more stringent, and by-products are produced during the reaction. Therefore, the adsorption hydrolysis method is the most promising technology due to its high efficiency and completeness: it uses a specific adsorbent to concentrate COS, and simultaneously catalyzes and promotes the hydrolysis reaction, significantly improving the removal efficiency.
[0004] Activated carbon has a highly developed and controllable pore structure, and its large specific surface area and rich adsorption sites are beneficial to efficient enrichment of low-concentration COS. Its surface chemical properties are easy to modify, which can simultaneously promote adsorption and catalytic hydrolysis reaction, making it an ideal catalyst carrier. The existing activated carbon materials still have obvious limitations: 1) limited sulfur capacity, easy to reach saturation; 2) insufficient matching of pore structure (such as pore size distribution) with pollutant molecular kinetic diameter, resulting in poor adsorption stability (easy to desorb); 3) there is still a large space for improvement in overall desulfurization efficiency. Therefore, it is necessary to modify and develop activated carbon materials. SUMMARY
[0005] The application aims to provide a preparation method of a biomass-based simultaneous removal of blast furnace gas COS and H2S activated carbon catalyst with high sulfur capacity.
[0006] The application provides a preparation method of a biomass-based simultaneous removal of blast furnace gas COS and H2S activated carbon catalyst.
[0007] Further, after the hydrothermal reaction, the modified activated carbon is washed, dried and activated to obtain the activated carbon catalyst.
[0008] Further, the drying temperature is 90°C-110°C.
[0009] Further, the alkaline solution is a KOH solution.
[0010] Further, the mass ratio of potassium hydroxide in the KOH solution to the biochar is (1.5-3):1. Preferably, the mass ratio of the potassium hydroxide to the biochar is 2:1.
[0011] Further, the concentration of the alkaline solution is 10 wt.%-25 wt.%, preferably, the alkaline solution is a potassium hydroxide concentration, and the potassium hydroxide concentration is 20 wt.% and the urea concentration is 6 wt.%.
[0012] Further, the mass ratio of the urea to the biochar is (0.05-1):1. Preferably, the mass ratio of the urea to the biochar is 0.3:1.
[0013] Further, the mass ratio of the aluminum nitrate to the biochar is (0.5-1.5):1. Preferably, the mass ratio of the aluminum nitrate to the biochar is 1:1.
[0014] Further, the temperature of the hydrothermal reaction is 170°C-180°C.
[0015] Further, the activation method of the modified activated carbon is to place the modified activated carbon in a reaction container, introduce N2 as a protective gas in the reaction container, heat to 600°C-900°C, and then constant temperature activation.
[0016] The preparation method of the activated carbon catalyst provided by the application comprises the following steps:
[0017] 1) Selecting wood active carbon, crushing, grinding, screening;
[0018] 2) Hydrothermal mixing of the biomass carbon with KOH, urea and aluminum nitrate;
[0019] 3) After drying the obtained mixture, calcination treatment is carried out to obtain modified active carbon.
[0020] In the method described in the application, preferably, in step 1), the biomass raw material is crushed, ground and screened to obtain a powder with a particle size of 40-60 mesh.
[0021] In the method described in the application, preferably, in step 2), the impregnated material is activated in a tube furnace, and 200 ml / min N2 is introduced as a protective gas during activation, the temperature is raised to 850 °C at a rate of 10 °C / min, and the activation time is 2h.
[0022] On the other hand, the application provides a biomass-based simultaneous removal of blast furnace gas COS and H2S active carbon catalyst prepared by the above preparation method.
[0023] The application uses a hydrothermal method to modify the biomass carbon material with urea, aluminum nitrate and potassium hydroxide to control the surface basicity and oxygen vacancies; the modified biomass carbon material is calcined at high temperature, the distribution of Al2O3 is improved by the anchoring effect of pyridine N, and the formation of additional active oxygen species in the system is promoted, and the desulfurization active carbon material is obtained after cooling to room temperature. The application uses environmentally friendly biomass carbon and cheap chemical raw materials, which are efficiently converted into active carbon materials with excellent COS and H2S adsorption performance through the above process.
[0024] Advantages: Compared with the prior art, the application has the following obvious advantages: (1) The application uses renewable wood biomass as a carbon source to replace traditional coal-based active carbon, uses agricultural / forestry waste biomass, reduces solid waste pollution, and reduces raw material cost.
[0025] (2) The application synchronously introduces KOH alkali modifier, urea and aluminum nitrate by hydrothermal method, realizes surface alkaline functional group grafting, N doping and aluminum loading in one step, and significantly enhances the synergistic chemical adsorption capacity of COS and H2S.
[0026] (3) The hydrothermal and calcination described in the application are mature industrial technologies, which do not require complex equipment, have mild reaction conditions (atmospheric hydrothermal, inert atmosphere calcination), and are safe to operate. BRIEF DESCRIPTION OF DRAWINGS
[0027] Figure 1 is a performance diagram of different precursor catalysts for removing H2S.
[0028] Figure 2 is a performance graph of different precursor catalysts for removing COS.
[0029] Figure 3 is a performance graph of catalysts prepared by different methods for removing COS.
[0030] Figure 4 is the sulfur capacity of catalysts with different metal salt loadings. DETAILED DESCRIPTION
[0031] In order to make the content of the present application more convenient to understand, the technical solutions of the present application are further described below in combination with specific embodiments, but the present application is not limited to this.
[0032] The endpoints of the ranges and any values disclosed herein are not limited to the precise values stated. The endpoints of the ranges and values are provided as approximate values, and the ranges and values should be understood to encompass values approximately the same as the stated values. For numeric values, the endpoints of each range, the endpoints of each range and individual point values, and individual point values can be combined with each other to form one or more new numeric ranges, which should be considered as specifically disclosed herein.
[0033] In the modified activated carbon catalyst of the present application, preferably, the content of the metal salt is 0.5-1.5 parts by weight, more preferably 1 part by weight, relative to 1 part by weight of the activated carbon; and the content of KOH is 1.5-3 parts by weight, more preferably 2 parts by weight.
[0034] In the present application, the component content in the above range is selected to ensure the synergistic adsorption of COS and H2S, which is beneficial to obtain better adsorption performance.
[0035] In the modified activated carbon material of the present application, preferably, the metal salt is aluminum nitrate. In the present application, the selection of aluminum nitrate is beneficial to further improve the adsorption capacity of COS and H2S.
[0036] In the modified activated carbon material of the present application, preferably, the specific surface area of the modified activated carbon material is 636 m 2 / g, the sulfur capacity is 166.2 mg S / g under the conditions of a reaction temperature of 75℃, a space velocity of 20000 h -1 -1, and a sulfur dioxide concentration of 100 ppm.
[0037] In the present application, the sulfur capacity refers to the adsorption capacity reaching the breakthrough time, and the breakthrough time is the time when the efficiency decreases to 90%.
[0038] The modified activated carbon material, its preparation method, and its application according to the present invention are further illustrated by the following examples. Unless otherwise specified, the experimental methods used in the following examples are conventional methods in the art. Unless otherwise specified, the experimental materials used in the following examples are commercially available.
[0039] Example 1
[0040] This embodiment provides a method for preparing an activated carbon catalyst, comprising the following steps:
[0041] (1) Pretreatment: The wood biochar powder is crushed and screened to obtain 40-mesh powder.
[0042] (2) Modification: Mix 6 g KOH with 24 ml H2O and sonicate for 10 min; add 0.8 g urea to the solution and sonicate for 10 min; add 2.4 g 40 mesh biochar powder to the solution and sonicate for 10 min; add 2.4 g aluminum nitrate powder and sonicate for 60 min; transfer the mixture to a reaction vessel and hydrothermally react at 175 °C for 12 h; after the reaction is completed, cool to room temperature, wash with deionized water and centrifuge 3 times, and dry in an oven at 100 °C for 8 h.
[0043] (3) Calcination: The modified activated carbon was placed in a tube furnace and N2 protective gas was introduced (flow rate 200 mL / min); the temperature was raised to 850°C at 10°C / min, and the activated carbon was kept at a constant temperature for 2 h, and then naturally cooled to room temperature; the product was washed with deionized water until neutral, and dried at 100°C to obtain desulfurized activated carbon.
[0044] Examples 2-5
[0045] This embodiment provides a method for preparing an activated carbon catalyst, including the following steps: (1) Ash removal: same as in Example 1.
[0046] (2) Modification: Same as Example 1, but the mass of aluminum nitrate was changed to 1.2 g (Example 2), 1.68 g (Example 3), 3.12 g (Example 4), and 3.6 g (Example 5), respectively.
[0047] (3) Calcination: Same as in Example 1.
[0048] Example 6
[0049] The difference between this embodiment and Example 1 is as follows: In this embodiment, the mass ratio of biochar:KOH:urea;aluminum nitrate is 1:3:1:1.5; the KOH solution concentration is 25 wt.%; the drying temperature is 110 °C; the hydrothermal reaction temperature is 180 °C; and the activation temperature is 900 °C. The remaining steps are the same as in Example 1.
[0050] Example 7
[0051] The difference between this embodiment and Example 1 is as follows: In this embodiment, the mass ratio of biochar:KOH:urea; aluminum nitrate is 1:1.5:0.05:0.5; the KOH solution concentration is 10 wt.%; the drying temperature is 90 °C; the hydrothermal reaction temperature is 170 °C; and the activation temperature is 600 °C. The remaining steps are the same as in Example 1.
[0052] Comparative Example 1
[0053] This comparative example provides a method for preparing an activated carbon catalyst, comprising the following steps:
[0054] (1) Ash removal: Same as in Example 1.
[0055] (2) Modification: Same as in Example 1, but aluminum nitrate is replaced with aluminum chloride reagent.
[0056] (3) Calcination: Same as in Example 1.
[0057] Comparative Example 2
[0058] This comparative example uses a non-hydrothermal method for modification, specifically including the following steps:
[0059] (1) Pretreatment: The wood biochar powder is crushed and screened to obtain 40-mesh powder.
[0060] (2) Modification: Mix 6 g KOH with 24 ml H2O and sonicate for 10 min; add 0.8 g urea to the solution and sonicate for 10 min; add 2.4 g 40-60 mesh biochar powder to the solution and sonicate for 10 min; add 2.4 g aluminum nitrate powder and sonicate for 60 min.
[0061] (3) Calcination: The modified activated carbon was placed in a tube furnace and N2 protective gas was introduced (flow rate 200 mL / min); the temperature was raised to 850°C at 10°C / min, and the activated carbon was kept at a constant temperature for 2 h, and then naturally cooled to room temperature; the product was washed with deionized water until neutral, and dried to obtain desulfurized activated carbon.
[0062] Figures 1-4The results were determined using a desulfurization testing platform and gas chromatography. The results showed that metal doping of KOH-modified activated carbon effectively improved COS removal efficiency. As shown in the figure, the COS removal efficiency of the catalysts after N doping and K / Al modification exhibited a volcano-shaped trend. The catalyst exhibited the longest COS breakthrough duration (75 °C, 1600 min) and also the highest sulfur capacity. However, neither aluminum loading nor N doping reduced catalytic activity. As shown in the figure, N doping further improved the COS removal efficiency of the catalyst. The figure indicates that the example achieved the highest sulfur capacity reported to date, demonstrating a significant advantage compared to recently recorded activated carbon-based catalysts.
[0063] The above embodiments are only used to illustrate the detailed method of the present invention. The present invention is not limited to the above detailed method, that is, it does not mean that the present invention must rely on the above detailed method to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.
Claims
1. A method for preparing a biomass-based activated carbon catalyst for simultaneous removal of COS and H2S from blast furnace gas, characterized in that, Urea is added to an alkaline solution and mixed evenly to obtain a modifier solution; the modifier solution and aluminum nitrate are added to biochar powder and then subjected to a hydrothermal reaction. After the hydrothermal reaction is completed, modified activated carbon is obtained. The modified activated carbon was activated to obtain the activated carbon catalyst.
2. The method for preparing the activated carbon catalyst according to claim 1, characterized in that, After the hydrothermal reaction is completed, the modified activated carbon is washed, dried, and then activated to obtain the activated carbon catalyst.
3. The method for preparing the activated carbon catalyst according to claim 2, characterized in that, The drying temperature is 90 °C-110 °C.
4. The method for preparing the activated carbon catalyst according to claim 1, characterized in that, The alkaline solution is a KOH solution.
5. The method for preparing the activated carbon catalyst according to claim 4, characterized in that, The mass ratio of potassium hydroxide to biochar in the KOH solution is (1.5-3):1; the mass ratio of urea to biochar is (0.05-1):
1.
6. The method for preparing the activated carbon catalyst according to claim 1, characterized in that, The concentration of the alkaline solution is 10 wt.%-25 wt.%.
7. The method for preparing the activated carbon catalyst according to claim 1, characterized in that, The mass ratio of aluminum nitrate to biochar is (0.5~1.5):
1.
8. The method for preparing the activated carbon catalyst according to claim 1, characterized in that, The hydrothermal reaction temperature is 170°C - 180°C.
9. The method for preparing the activated carbon catalyst according to claim 1, characterized in that, The activation method for modified activated carbon involves placing the modified activated carbon in a reaction vessel, introducing N2 as a protective gas into the reaction vessel, heating it to 600°C-900°C, and then activating it at a constant temperature.
10. A biomass-based activated carbon catalyst for simultaneous removal of COS and H2S from blast furnace gas, prepared by any one of the preparation methods described in claims 1-9.