Activated carbon catalyst for flue gas desulfurization and preparation method
By preparing aminonaphthoic acid-grafted cellulose and calcining it at high temperature to form porous activated carbon, the problems of uneven catalyst distribution and poor char formation were solved, and a highly efficient flue gas desulfurization effect was achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- LIAONING INST OF SCI & TECH
- Filing Date
- 2026-01-20
- Publication Date
- 2026-05-22
AI Technical Summary
Existing flue gas desulfurization catalysts suffer from uneven catalyst distribution and easy agglomeration of active components, resulting in low catalytic desulfurization performance. Furthermore, the cellulose has poor char-forming properties, making it difficult to obtain porous activated carbon materials with high specific surface area and high porosity.
Aminonaphthoic acid grafted cellulose was prepared by Schiff base reaction. Aldehyde cellulose was ionically crosslinked with the amino group of 6-amino-2-naphthoic acid to form a porous spatial crosslinking network. High-temperature calcination was then used to form porous activated carbon with high specific surface area, which uniformly dispersed Cu2+ catalytic active components and generated copper oxide active sites through high-temperature oxidation.
It significantly improved the specific surface area and pore abundance of the catalyst, enhanced its adsorption capacity and catalytic activity for sulfur dioxide, reduced the sulfur dioxide content in flue gas, and improved the catalytic desulfurization performance.
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Figure CN121623829B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of flue gas desulfurization catalyst technology, specifically to an activated carbon catalyst for flue gas desulfurization and its preparation method. Background Technology
[0002] Industrial exhaust gases from sulfuric acid plants, smelters, and other industrial plants contain large amounts of sulfur dioxide, which can cause serious pollution to the atmospheric environment. Currently, the main method for treating sulfur dioxide in flue gas is chemical adsorption, which eliminates sulfur dioxide through adsorption, acid-base neutralization, and chemical reactions. The active components of the catalyst mainly include copper oxide, manganese dioxide, and molybdenum oxide, while the catalyst supports mainly include activated carbon, alumina, and molecular sieves.
[0003] Activated carbon, with its large specific surface area, excellent adsorption performance, and high chemical stability, is an ideal carrier for flue gas desulfurization catalysts. It is typically loaded with active catalytic components using an impregnation method. However, this method suffers from uneven catalyst distribution and agglomeration of active components, negatively impacting the catalyst's desulfurization performance. Precursors for activated carbon mainly include coal, biomass, and high-molecular polymers. Cellulose, in particular, is inexpensive and environmentally friendly, making it widely used in activated porous carbon materials. However, cellulose has poor char-forming properties, making it difficult to obtain porous activated carbon materials with high specific surface area and high porosity. Summary of the Invention
[0004] This invention solves the problem of low desulfurization performance of copper-based activated carbon catalysts.
[0005] The technical solution of this invention is: a method for preparing an activated carbon catalyst for flue gas desulfurization.
[0006] (1) Add water and cellulose to the reaction vessel, stir and add sodium periodate to carry out the reaction, add ethylene glycol, stir and filter, wash the precipitate with water, dry and obtain aldehyde cellulose.
[0007] (2) Add ethanol and aldehyde cellulose to the reaction vessel, heat and stir, add 6-amino-2-naphthoic acid and sodium hydroxide, react, filter, wash with ethanol, and dry to obtain aminonaphthoic acid grafted cellulose.
[0008] (3) Add water and copper salt to the container, stir, add aminonaphthic acid grafted cellulose, carry out ionic crosslinking, filter, place the crosslinking product in a tube furnace, calcine, activate, and cool to obtain activated carbon catalyst for flue gas desulfurization.
[0009] Furthermore, in (1), the ratio of cellulose to sodium periodate is 100g: (20-70)g.
[0010] Furthermore, in (1), the reaction temperature is 40-60℃, the reaction time is 3-5h, and the reaction is carried out in the dark.
[0011] Furthermore, in (2), the ratio of aldehyde cellulose, 6-amino-2-naphthoic acid and sodium hydroxide is 100g: (8-30)g: (1.8-6.5)g.
[0012] Furthermore, in (2), the reaction temperature is 60-80℃, the reaction time is 5-8h, and reflux is used during the reaction.
[0013] Furthermore, (3) the temperature for ionic crosslinking is 15-40℃ and the time is 1-2h.
[0014] Furthermore, in (3), the ratio of copper salt and aminonaphthoic acid grafted cellulose is (40-120) g: 100 g.
[0015] Furthermore, in (3), the copper salt is either copper nitrate or copper sulfate.
[0016] Furthermore, in (3), calcination is carried out in a nitrogen atmosphere, with the temperature increased to 650-750℃ at a rate of 3-5℃ / min, and held for 2-3 hours.
[0017] Furthermore, in (3), the activation is carried out in an air atmosphere and kept at 400-450℃ for 1.5-2 hours.
[0018] The beneficial technical effects of this invention are as follows: By reacting the aldehyde group of aldehyde cellulose with the amino group of 6-amino-2-naphthoic acid via a Schiff base reaction, aminonaphthoic acid-grafted cellulose is obtained, which contains a large number of carboxyl groups and reacts with Cu... 2+ Ionic crosslinking occurs, causing cellulose to form a porous, three-dimensional crosslinked network. After high-temperature calcination, using the cellulose matrix and highly char-forming naphthalene rings as carbon sources, porous activated carbon with a high specific surface area and high stability carbon framework is formed, along with uniformly dispersed Cu. 2+ Through high-temperature thermal reduction and high-temperature oxidation, a large amount of copper oxide catalytic active components are generated in the activated carbon matrix.
[0019] The activated carbon catalyst in this invention has a large specific surface area and abundant pores, which can effectively adsorb sulfur dioxide and expose more copper oxide catalytic active sites, promoting the reaction between copper oxide and sulfur dioxide, thereby reducing the content and concentration of sulfur dioxide in flue gas. In addition, the aminonaphthoic acid grafted cellulose contains a large amount of nitrogen element, which forms an active nitrogen structure in the activated carbon matrix after high-temperature calcination. The nitrogen atom contains lone pair electrons and is alkaline, which can improve the adsorption capacity of activated carbon for SO2 and significantly improve the sulfur penetration capacity of the catalyst. Attached Figure Description
[0020] Figure 1This is a scanning electron microscope image of the activated carbon catalyst used for flue gas desulfurization in Example 1. Detailed Implementation
[0021] In this invention, unless otherwise stated, the scientific and technical terms used herein have the meanings commonly understood by those skilled in the art. Furthermore, the related terms and laboratory procedures used herein are all widely used terms and routine procedures in the respective fields. To better understand this invention, definitions and explanations of related terms are provided below.
[0022] Example 1:
[0023] (1) Add 150 mL of water and 10 g of cellulose to the reaction vessel, heat to 50 °C, stir, add 2 g of sodium periodate, react in the dark for 3 h, add 30 mL of ethylene glycol, stir, filter, wash the precipitate with water, dry, and obtain aldehyde cellulose.
[0024] (2) Add 800 mL of ethanol and 20 g of aldehyde cellulose to the reaction vessel, heat to 60 °C, stir, add 1.6 g of 6-amino-2-naphthoic acid and 0.36 g of sodium hydroxide, reflux for 6 h, filter, wash with ethanol, and dry to obtain aminonaphthoic acid grafted cellulose.
[0025] (3) Add 600 mL of water and 8 g of copper nitrate to the container, stir, and then add 20 g of aminonaphthyl carboxylic acid grafted cellulose. Perform ionic crosslinking at 20 °C for 1 h. After filtration, place the crosslinking product in a tube furnace, introduce nitrogen gas, and heat to 700 °C at a rate of 5 °C / min. Keep calcined for 2 h, cool to 400 °C, introduce air, keep calcined for 2 h, and cool to obtain activated carbon catalyst for flue gas desulfurization.
[0026] Example 2:
[0027] (1) Add 150 mL of water and 10 g of cellulose to the reaction vessel, heat to 60 °C, stir and add 3.5 g of sodium periodate, react in the dark for 3 h, add 40 mL of ethylene glycol, stir and filter, wash the precipitate with water and dry to obtain aldehyde cellulose.
[0028] (2) Add 800 mL of ethanol and 20 g of aldehyde cellulose to the reaction vessel, heat to 70 °C, stir, add 3 g of 6-amino-2-naphthoic acid and 0.65 g of sodium hydroxide, reflux for 5 h, filter, wash with ethanol, and dry to obtain aminonaphthoic acid grafted cellulose.
[0029] (3) Add 700 mL of water and 13 g of copper nitrate to the container, stir, and then add 20 g of aminonaphthyl carboxylic acid grafted cellulose. Perform ionic crosslinking at 15 °C for 2 h. After filtration, place the crosslinking product in a tube furnace, introduce nitrogen gas, and heat to 700 °C at a rate of 5 °C / min. Keep it at the temperature for 3 h, cool to 400 °C, introduce air, keep it at the temperature for 2 h, and cool to obtain activated carbon catalyst for flue gas desulfurization.
[0030] Example 3:
[0031] (1) Add 200 mL of water and 10 g of cellulose to the reaction vessel, heat to 40 °C, stir and add 5 g of sodium periodate, react in the dark for 5 h, add 50 mL of ethylene glycol, stir and filter, wash the precipitate with water and dry to obtain aldehyde cellulose.
[0032] (2) Add 900 mL of ethanol and 20 g of aldehyde cellulose to the reaction vessel, heat to 80 °C, stir, add 4.5 g of 6-amino-2-naphthoic acid and 0.97 g of sodium hydroxide, reflux for 5 h, filter, wash with ethanol, and dry to obtain aminonaphthoic acid grafted cellulose.
[0033] (3) Add 700 mL of water and 18 g of copper sulfate to the container, stir, and then add 20 g of aminonaphthyl carboxylic acid grafted cellulose. Perform ionic crosslinking at 40 °C for 1 h. After filtration, place the crosslinking product in a tube furnace, introduce nitrogen gas, and heat to 750 °C at a rate of 5 °C / min. Keep calcined for 2 h, cool to 400 °C, introduce air, keep calcined for 2 h, and cool to obtain activated carbon catalyst for flue gas desulfurization.
[0034] Example 4:
[0035] (1) Add 200 mL of water and 10 g of cellulose to the reaction vessel, heat to 50 °C, stir and add 7 g of sodium periodate, react in the dark for 5 h, add 50 mL of ethylene glycol, stir and filter, wash the precipitate with water and dry to obtain aldehyde cellulose.
[0036] (2) Add 900 mL of ethanol and 20 g of aldehyde cellulose to the reaction vessel, heat to 70 °C, stir, add 6 g of 6-amino-2-naphthoic acid and 1.3 g of sodium hydroxide, reflux for 8 h, filter, wash with ethanol, and dry to obtain aminonaphthoic acid grafted cellulose.
[0037] (3) Add 800 mL of water and 24 g of copper nitrate to the container, stir, and then add 20 g of aminonaphthyl carboxylic acid grafted cellulose. Perform ionic crosslinking at 30 °C for 2 h. After filtration, place the crosslinking product in a tube furnace, introduce nitrogen gas, and heat to 650 °C at a rate of 3 °C / min. Keep calcined for 3 h, cool to 450 °C, introduce air, keep calcined for 1.5 h, and cool to obtain activated carbon catalyst for flue gas desulfurization.
[0038] Comparative Example 1:
[0039] (1) Add 150 mL of water and 10 g of cellulose to the reaction vessel, heat to 50 °C, stir, add 2 g of sodium periodate, react in the dark for 3 h, add 30 mL of ethylene glycol, stir, filter, wash the precipitate with water, dry, and obtain aldehyde cellulose.
[0040] (2) Add 600 mL of water and 8 g of copper nitrate to the container, stir, add 20 g of aldehyde cellulose, and carry out ionic crosslinking at 20 °C for 1 h. After filtration, place the crosslinking product in a tube furnace, introduce nitrogen gas, heat to 700 °C at a rate of 5 °C / min, keep warm and calcine for 2 h, cool to 400 °C, introduce air, keep warm and activate for 2 h, cool, and obtain activated carbon catalyst.
[0041] Comparative Example 2:
[0042] (1) Add 150 mL of water and 10 g of cellulose to the reaction vessel, heat to 50 °C, stir, add 2 g of sodium periodate, react in the dark for 3 h, add 30 mL of ethylene glycol, stir, filter, wash the precipitate with water, dry, and obtain aldehyde cellulose.
[0043] (2) Add 800 mL of ethanol and 20 g of aldehyde cellulose to the reaction vessel, heat to 60 °C, stir, add 1.6 g of β-alanine and 0.36 g of sodium hydroxide, reflux for 6 h, filter, wash with ethanol, and dry to obtain alanine-grafted cellulose.
[0044] (3) Add 600 mL of water and 8 g of copper nitrate to the container, stir, add 20 g of alanine-grafted cellulose, and carry out ionic cross-linking at 20 °C for 1 h. After filtration, place the cross-linking product in a tube furnace, introduce nitrogen gas, heat to 700 °C at a rate of 5 °C / min, keep warm and calcine for 2 h, cool to 400 °C, introduce air, keep warm and activate for 2 h, cool, and obtain activated carbon catalyst.
[0045] Comparative Example 3:
[0046] (1) Add 150 mL of water and 10 g of cellulose to the reaction vessel, heat to 50 °C, stir, add 2 g of sodium periodate, react in the dark for 3 h, add 30 mL of ethylene glycol, stir, filter, wash the precipitate with water, dry, and obtain aldehyde cellulose.
[0047] (2) Add 800 mL of ethanol and 20 g of aldehyde cellulose to the reaction vessel, heat to 60 °C, stir, add 1.6 g of 2-naphthylamine and 0.36 g of sodium hydroxide, reflux for 6 h, filter, wash with ethanol, and dry to obtain naphthylamine grafted cellulose.
[0048] (3) Add 600 mL of water and 8 g of copper nitrate to the container, stir, add 20 g of naphthylamine grafted cellulose, carry out ionic cross-linking at 20 °C for 1 h, filter, place the cross-linking product in a tube furnace, introduce nitrogen gas, heat to 700 °C at a rate of 5 °C / min, keep warm and calcine for 2 h, cool to 400 °C, introduce air, keep warm and activate for 2 h, cool to obtain activated carbon catalyst.
[0049] The specific surface area and pore volume of the activated carbon catalyst were determined by nitrogen adsorption-desorption isotherm method using a specific surface area and pore size analyzer.
[0050] 0.6 g of activated carbon catalyst was weighed and placed in a bed flow reactor. A mixture of sulfur dioxide, oxygen, and argon in a volume ratio of 0.18:10:89.82 was introduced as simulated flue gas. The reaction temperature was set at 200 °C and the space velocity was set at 30,000 h⁻¹. -1 After the reaction, the sulfur dioxide concentration in the simulated flue gas was measured by a flue gas analyzer to obtain the breakthrough sulfur capacity.
[0051] Table 1 Performance Tests of Activated Carbon Catalysts
[0052]
[0053] The activated carbon catalysts in Examples 1-4 exhibit higher specific surface area and total pore volume, along with high sulfur penetration capacity and high adsorption and reactivity for sulfur dioxide. This is mainly because aminonaphthoic acid-grafted cellulose contains a large number of carboxyl groups, which react with Cu... 2+ Ionic crosslinking occurs, causing cellulose to form a porous, three-dimensional crosslinked network. After high-temperature calcination, using the cellulose matrix and highly char-forming naphthalene rings as carbon sources, porous activated carbon with a high specific surface area and high stability carbon framework is formed, along with uniformly dispersed Cu. 2+Through high-temperature thermal reduction and high-temperature oxidation, a large amount of copper oxide catalytic active components are generated in the activated carbon matrix. The porous activated carbon with high specific surface area can effectively adsorb sulfur dioxide and expose more copper oxide catalytic active sites, promoting the reaction between copper oxide and sulfur dioxide, thereby reducing the concentration of sulfur dioxide. In addition, aminonaphthoic acid grafted cellulose contains a large amount of nitrogen element, which forms an active nitrogen structure in the activated carbon matrix after high-temperature calcination. The nitrogen atom contains lone pair electrons and is alkaline, which can improve the adsorption capacity of activated carbon for SO2.
[0054] Compared with Example 1, the aldehyde cellulose in Comparative Example 1 does not contain carboxyl groups and cannot undergo ionic cross-linking with copper ions. The cross-linking products are difficult to form a spatial cross-linking network. The copper ion content of the cross-linking products after filtration is very low, resulting in a very small specific surface area and pore volume of activated carbon. The content of copper oxide catalytic active components in activated carbon is also very low, and activated carbon does not contain active nitrogen structures, which seriously affects the sulfur penetration capacity of activated carbon.
[0055] Comparative Example 2: Alanine-grafted cellulose does not contain a naphthalene ring structure, the cross-linked product has poor char-forming properties and poor carbon skeleton stability, and the prepared activated carbon has a small specific surface area and pore volume, which affects the sulfur penetration capacity of the activated carbon.
[0056] The naphthylamine-grafted cellulose in Comparative Example 3 does not contain carboxyl groups and cannot undergo ionic cross-linking with copper ions. The cross-linking products are difficult to form a spatial cross-linking network. The copper ion content of the cross-linking products after filtration is very low, resulting in a very small specific surface area and pore volume of activated carbon. The content of copper oxide catalytic active components in activated carbon is also very low, which affects the sulfur penetration capacity of activated carbon.
[0057] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.
Claims
1. A method for preparing an activated carbon catalyst for flue gas desulfurization, characterized in that, The preparation method includes: adding water and copper salt to a container, stirring, adding aminonaphthoic acid-grafted cellulose, performing ionic crosslinking at 15-40℃ for 1-2 hours, filtering, placing the crosslinking product in a tube furnace, introducing nitrogen gas, heating to 650-750℃, holding at that temperature for 2-3 hours, then cooling to 400-450℃, introducing air, activating for 1.5-2 hours, and cooling to obtain an activated carbon catalyst for flue gas desulfurization.
2. The method for preparing activated carbon catalyst for flue gas desulfurization according to claim 1, characterized in that, The ratio of copper salt and aminonaphthoic acid grafted cellulose is (40-120) g: 100 g.
3. The method for preparing activated carbon catalyst for flue gas desulfurization according to claim 2, characterized in that, The copper salt is copper nitrate or copper sulfate.
4. The method for preparing activated carbon catalyst for flue gas desulfurization according to claim 1, characterized in that, The heating rate is 3-5℃ / min.
5. The method for preparing activated carbon catalyst for flue gas desulfurization according to claim 2, characterized in that, The method for preparing the aminonaphthoic acid-grafted cellulose includes: (1) Add water and cellulose to the reaction vessel, stir, add sodium periodate, react, add ethylene glycol, stir, filter, wash the precipitate, dry, and obtain aldehyde cellulose; (2) Add ethanol and aldehyde cellulose to the reaction vessel, heat and stir, add 6-amino-2-naphthoic acid and sodium hydroxide, react, filter, wash the product, and dry to obtain aminonaphthoic acid grafted cellulose.
6. The method for preparing activated carbon catalyst for flue gas desulfurization according to claim 5, characterized in that, The ratio of cellulose to sodium periodate in (1) is 100g: (20-70)g.
7. The method for preparing activated carbon catalyst for flue gas desulfurization according to claim 5, characterized in that, The reaction temperature in (1) is 40-60℃, the reaction time is 3-5h, and the reaction is carried out in the dark.
8. The method for preparing activated carbon catalyst for flue gas desulfurization according to claim 5, characterized in that, The ratio of aldehyde cellulose, 6-amino-2-naphthoic acid and sodium hydroxide in (2) is 100g: (8-30)g: (1.8-6.5)g.
9. The method for preparing activated carbon catalyst for flue gas desulfurization according to claim 5, characterized in that, The reaction temperature in (2) is 60-80℃, the reaction time is 5-8h, and reflux is carried out during the reaction.
10. An activated carbon catalyst for flue gas desulfurization obtained by the preparation method according to any one of claims 1-9.