A method for preparing a porous carbon material from petroleum coke and biomass

Abstract

The application discloses a method for preparing porous carbon material by taking petroleum coke and biomass as raw materials, and the biomass raw material and the petroleum coke raw material are respectively crushed and dried, the biomass fine powder dry material and the petroleum coke fine powder dry material are added into a reactor according to proportions of urotropin, melamine, alcohol ether carboxylate and water, and are stirred, mixed and reacted to obtain a solidification product; the solidification product is given into a tubular furnace to be heat-treated under a nitrogen atmosphere to obtain a carbonization product; and the carbonization product is activated under a carbon dioxide atmosphere to obtain the porous carbon material with a specific surface area of 1510-2090 m 2 / g, a total pore volume of 0.72-0.99 cm 3 / g and an average pore diameter of 1.71-2.29 nm. According to the application, the raw material proportion, the amount of mixing aid and the carbonization and activation conditions can be adjusted according to different types of biomass, the product pore distribution can be flexibly adjusted, and the method can be applied to different scenes. The method is not only low in cost and friendly to the environment, but also controllable in product stability, and is suitable for large-scale production and application.

Description

Technical Field

[0001] This invention belongs to the field of porous carbon material preparation, specifically relating to a method for preparing porous carbon materials using petroleum coke and biomass as raw materials. Background Technology

[0002] With the continuous adjustment of the global energy structure and the in-depth advancement of sustainable development strategies, efficient, environmentally friendly, and low-cost energy storage materials and functional materials have become important research directions in the field of materials science and engineering. Porous carbon materials, due to their unique physicochemical properties, such as high specific surface area, good electrical conductivity, chemical stability, and tunable pore structure, are widely used in various fields such as supercapacitors, lithium-ion batteries, CO2 adsorption, water treatment, and catalytic reactions. Therefore, developing an efficient, green, and high-performance porous carbon energy storage material is of great significance for promoting the development of new energy technologies and realizing the recycling of resources.

[0003] In recent years, research on biomass as a carbon source has gradually attracted attention. Biomass has advantages such as wide availability, high renewability, and low cost, making it one of the ideal raw materials for preparing porous carbon materials. For example, biomass such as rice husks, corn stalks, wheat straw, and sawdust can be converted into porous carbon materials during high-temperature pyrolysis. However, porous carbon materials prepared using biomass alone still have certain shortcomings in terms of specific surface area and pore structure, making it difficult to meet the requirements of high-performance energy storage materials. Therefore, how to combine multiple carbon sources through synergistic effects to improve the performance of porous carbon materials has become one of the current research focuses.

[0004] Petroleum coke, a typical industrial byproduct, has a wide range of sources, including byproducts from oil refineries and coking plants. With its high carbon content and low ash content, petroleum coke is an ideal raw material for preparing porous carbon materials. However, porous carbon materials prepared using petroleum coke alone still have certain limitations in terms of specific surface area and pore structure, making it difficult to meet the requirements of high-performance energy storage materials. Therefore, by designing a reasonable process to combine petroleum coke with biomass to prepare porous carbon materials, it is expected to achieve efficient resource utilization and synergistic performance improvement.

[0005] Chinese patent application 202311514003.2 discloses a biomass tar-based supercapacitor carbon, its preparation method, and its application. The method involves impregnating biomass tar with an alkaline activator, drying it, and then performing activation, acid washing, and water washing steps to obtain the biomass tar-based supercapacitor carbon. The pore size distribution of the biomass tar-based supercapacitor carbon material prepared by this method can be controlled by changing conditions such as the carbon-alkali ratio, activation time, and activation temperature, making large-scale production easily achievable. However, the final product quality is significantly affected by factors such as the origin of the raw materials and climate, making it difficult to guarantee product stability. Summary of the Invention

[0006] This invention addresses the technical challenges of porous carbon materials prepared solely from biomass or petroleum coke, including small specific surface area, unreasonable pore structure, unimproved electrochemical performance and adsorption capacity, and poor product stability. It provides a method for preparing porous carbon materials using petroleum coke and biomass as raw materials. By adding a mixing agent and adjusting the carbonization and activation processes, this method not only effectively utilizes both petroleum coke and biomass waste materials but also synergistically improves the specific surface area, pore structure, and surface chemical properties of the porous carbon materials, thereby enhancing their application performance in energy storage, adsorption, and catalysis.

[0007] To achieve the above-mentioned objectives of this invention, a method for preparing porous carbon materials using petroleum coke and biomass as raw materials is implemented using the following technical solution:

[0008] (1) Pretreatment of biomass: The biomass raw material is crushed to a particle size of 2-10 μm and then dried at 60-100℃ to obtain fine powder of biomass; the biomass includes, but is not limited to, any one, two or more of coconut shell, straw, rice husk, wood, bamboo, sugarcane bagasse, nut shell, wheat starch, and corn starch.

[0009] (2) Pretreatment of petroleum coke: The petroleum coke raw material is crushed to a particle size of 2-10 μm and then dried at 60-100℃ to obtain petroleum coke fine powder dry material;

[0010] (3) Raw material mixing and reaction curing: Biomass fine powder dry material and petroleum coke fine powder dry material are added to a reactor along with hexamethylenetetramine, melamine, alcohol ether carboxylate and water in a mass ratio of (50-200):(50-500):(1-50):(2-20):(1-30):(300-1000). The mixture is stirred and reacted, and the temperature inside the reactor is controlled at 85-98℃. After the reaction is completed, the reaction product is filtered to obtain a semi-dry material, which is then dried at 60-80℃ to obtain a cured product.

[0011] (4) Carbonization treatment: The cured product obtained in step (4) is fed into a tube furnace and heat-treated in a nitrogen atmosphere. The heat treatment is carried out in stages until the temperature reaches 700-900℃ and a carbonization reaction occurs to obtain the carbonized product.

[0012] (5) Activation treatment: The carbonized product obtained in step (4) is heated to 800℃-950℃ in a tube furnace and activated under a carbon dioxide atmosphere to obtain a specific surface area of ​​1510-2090 m². 2 / g, total pore volume 0.72-0.99cm³ 3 / g, porous carbon material with an average pore size of 1.71-2.29nm. The activation gas carbon dioxide flow rate is 10-200mL / min.

[0013] The pore structure of the prepared porous carbon material was tested, including specific surface area, total pore volume, and average pore size. Then, the prepared porous carbon material was used to test its electrochemical and adsorption performance, including cyclic voltammetry, constant current charge-discharge, adsorption capacity, and cycle performance.

[0014] Preferably, the drying time in step (1) is controlled at 18-24h; the drying time in step (2) is controlled at 6-12h; and the drying time in step (3) is 12-24h.

[0015] Preferably, in step (1), the biomass raw material is crushed to a particle size of 2-4 μm and dried at 90-110℃ for 16-20 h; in step (2), the petroleum coke raw material is crushed to a particle size of 2-4 μm and dried at 90-110℃ for 16-20 h.

[0016] Preferably, in step (3), the stirring speed in the reactor is controlled at 200-600 rpm and the reaction time is controlled at 5-10 h.

[0017] Preferably, the heat treatment in step (4) is carried out in three stages: ① first, the temperature is increased to 140-180℃ at 2-4℃ / min and held for 25-40min; ② then the temperature is increased to 360-450℃ at 0.8-1.5℃ / min and held for 1.2-1.9h; ③ then the temperature is increased to 750-880℃ at 4-6℃ / min and held for 3.5-5h.

[0018] Preferably, the activation treatment in step (5) is carried out in two stages: ① first, the temperature is raised to 420-500℃ in a carbon dioxide atmosphere at 2.5-4℃ / min and held for 0.9-1.2h; ② then the temperature is raised to 820-900℃ at 4.5-6℃ / min and held for 7.5-9h.

[0019] Preferably, in step (3), the biomass fine powder dry material, petroleum coke fine powder dry material, hexamethylenetetramine, melamine, alcohol ether carboxylate and water are added to the reactor in a mass ratio of (50-120):(90-250):(8-20):(2-10):(1-20):(450-1000) and stirred and reacted.

[0020] Further, in step (3), the fine powder of biomass, fine powder of petroleum coke, hexamethylenetetramine, melamine, alcohol ether carboxylate and water are added to the reactor in a mass ratio of (50-100): (100-250): (8-17): (2-9): (1-18): (500-1000) and stirred and reacted.

[0021] When the prepared porous carbon material is used to manufacture supercapacitors, the method of preparing porous carbon material using petroleum coke and biomass as raw materials according to the present invention is implemented using the following technical solution:

[0022] (1) Pretreatment of biomass: The biomass raw material is crushed to a particle size of 2-3 μm and then dried at 90-100℃ for 17-19 h to obtain fine biomass powder dry material;

[0023] (2) Pretreatment of petroleum coke: The petroleum coke raw material is crushed to a particle size of 2-3 μm, and then dried at 90-100℃ for 17-19 h to obtain petroleum coke fine powder dry material;

[0024] (3) Raw material mixing and reaction curing: Biomass fine powder dry material and petroleum coke fine powder dry material are added to the reactor along with hexamethylenetetramine, melamine, alcohol ether carboxylate and water in a mass ratio of (70-110):(90-150):(6-12):(2-3):(4-9):(450-600) and stirred for 4.5-6 hours. The temperature inside the reactor is controlled at 86-95℃. After the reaction is completed, the reaction product is filtered to obtain semi-dry material, which is then dried at 65-75℃ for 11-13 hours to obtain the cured product.

[0025] (4) Carbonization treatment: The cured product obtained in step (4) is fed into a tube furnace and heat-treated in a nitrogen atmosphere. The heat treatment is carried out in stages until the temperature is between 780-830℃ and held for 3.6-5 hours to produce a carbonization reaction and obtain a carbonized product.

[0026] (5) Activation treatment: The carbonized product obtained in step (4) is heated to 840℃-890℃ in a tube furnace and activated for 7-9 hours in a carbon dioxide atmosphere to obtain a specific surface area of ​​1510-1630 m². 2 / g, total pore volume 0.72-0.79cm³ 3 Porous carbon material with an average pore size of 1.71-1.85 nm per g, used for fabricating supercapacitors.

[0027] Supercapacitors were fabricated using the activated porous carbon material described above, with an initial specific capacitance of 180.1-185.5 F / g and a capacitance retention of 90.3%-91.9% after 100 cycles.

[0028] When the prepared porous carbon material is used as an adsorption material for treating heavy metal ions in wastewater, the present invention provides a method for preparing porous carbon materials using petroleum coke and biomass as raw materials, which is implemented using the following technical solution:

[0029] (1) Pretreatment of biomass: The biomass raw material is crushed to a particle size of 2-3 μm and then dried at 90-100℃ for 17-19 h to obtain fine biomass powder dry material;

[0030] (2) Pretreatment of petroleum coke: The petroleum coke raw material is crushed to a particle size of 2-3 μm, and then dried at 90-100℃ for 17-19 h to obtain petroleum coke fine powder dry material;

[0031] (3) Raw material mixing and reaction curing: Biomass fine powder dry material and petroleum coke fine powder dry material are added to the reactor along with hexamethylenetetramine, melamine, alcohol ether carboxylate and water in a mass ratio of (50-70):(180-280):(12-22):(4-11):(17-21):(900-1000) and stirred and mixed. The reaction is carried out for 7.5-8.5 hours, and the temperature inside the reactor is controlled at 86-95℃. After the reaction is completed, the reaction product is filtered to obtain semi-dry material, and then the semi-dry material is dried at 75-85℃ for 11-13 hours to obtain the cured product.

[0032] (4) Carbonization treatment: The cured product obtained in step (4) is fed into a tube furnace and heat-treated in a nitrogen atmosphere. The heat treatment is carried out in stages until the temperature is between 830-870℃ and maintained for 3.6-5h to produce a carbonization reaction and obtain a carbonized product.

[0033] (5) Activation treatment: The carbonized product obtained in step (4) is heated to 830℃-850℃ in a tube furnace and activated for 7-9 hours in a carbon dioxide atmosphere to obtain a specific surface area of ​​1950-2090 m². 2 / g, total pore volume 0.96-0.99cm³ 3 Porous carbon materials with an average pore size of 2.11-2.29 nm and a g / g, used for adsorbing heavy metal ions in wastewater.

[0034] Using the activated porous carbon material to treat heavy metal ions (Cd) in wastewater 2+ The initial adsorption rate reached 93%-95%, and after 10 cycles, the adsorption rate remained at 87%-90%.

[0035] Compared with existing technologies, the pore size distribution of the biomass tar-based supercapacitive carbon material prepared by this invention can be controlled by changing conditions such as carbon-alkali ratio, activation time, and activation temperature, making it easy to achieve large-scale production. However, the final product quality is greatly affected by factors such as raw material origin and climate, making it difficult to guarantee product stability. It has the following beneficial effects:

[0036] (1) Low cost: Biomass and petroleum coke are used as raw materials, which are low cost and widely available.

[0037] (2) Environmentally friendly: The entire preparation process does not require the use of a large number of chemical reagents, reducing wastewater discharge and conforming to the concept of green chemistry.

[0038] (3) Excellent performance: The prepared porous carbon material has a reasonable pore size structure, high specific surface area, and excellent electrochemical performance and adsorption capacity, and can be used to make supercapacitors and for the adsorption treatment of various pollutants. Using the activated porous carbon material to make a supercapacitor, the initial specific capacitance was 180.1-185.5 F / g, and after 100 cycles, the capacity retention rate was 90.3%-91.9%. The activated porous carbon material was also used to treat heavy metal ions (Cd) in wastewater. 2+ The initial adsorption rate reached 93%-95%, and after 10 cycles, the adsorption rate remained at 87%-90%.

[0039] (4) Product stability is controllable: The product pore distribution can be flexibly adjusted according to the raw material ratio, mixing agent dosage, carbonization and activation process conditions, etc., based on the differences in raw materials, to effectively ensure the stability of the final product. Detailed Implementation

[0040] The present invention will now be described in detail with reference to specific embodiments. The illustrative embodiments and descriptions herein are used to explain the invention but are not intended to limit it. Based on the technical concept and embodiments of the present invention, any modifications, equivalent substitutions, and improvements made by those skilled in the art within the spirit and principles of the invention should be included within the protection scope of the present invention.

[0041] Example 1

[0042] Take appropriate amounts of rice husks and petroleum coke, crush them separately using a crusher, and sieve them through a 5000-mesh screen. Take the powder passing through the sieve and dry it at 100℃ for 18 hours. Take 100g of rice husk powder, 100g of petroleum coke powder, 10g of hexamethylenetetramine, 2g of melamine, 5g of alcohol ether carboxylate AEC-9Na, and 500mL of water in a flask, and stir at 90℃ for 5 hours at a stirring speed of 400rpm. After the reaction is complete, filter and dry the resulting solid product in a 70℃ oven for 12 hours.

[0043] The product was then heated to 150℃ in a nitrogen atmosphere at a rate of 3℃ / min and held for 30 min, followed by a rate of 1℃ / min to 400℃ and held for 1.5 h, then a rate of 5℃ / min to 800℃ and held for 4 h, before being allowed to cool naturally to room temperature. 5 g of the carbonized product was then heated to 450℃ in a carbon dioxide atmosphere at a rate of 3℃ / min and held for 1 h, followed by a rate of 5℃ / min to 850℃ and held for 8 h, with a gas flow rate of 3 mL / min. The activated sample had a specific surface area of ​​1578 m². 2 / g, total pore volume 0.743cm³ 3 / g, with an average pore size of 1.74nm. The activated product was used to prepare a supercapacitor with an initial specific capacitance of 183.4F / g and a capacitance retention of 90.4% after 100 cycles.

[0044] Example 2

[0045] Take appropriate amounts of coconut shell and petroleum coke, crush them separately using a crusher, and sieve them through a 5000-mesh screen. Dry the powder passing through the sieve at 100℃ for 18 hours. Take 80g of coconut shell powder, 130g of petroleum coke powder, 8g of hexamethylenetetramine, 2g of melamine, 7g of alcohol ether carboxylate AEC-9Na, and 500mL of water in a flask, and stir at 90℃ for 5 hours at a stirring speed of 400 rpm. After the reaction is complete, filter and dry the resulting solid product in a 70℃ oven for 12 hours.

[0046] The product was then heated to 150℃ in a nitrogen atmosphere at a rate of 3℃ / min and held for 30 min, followed by a rate of 1℃ / min to 400℃ and held for 1.5 h, then a rate of 5℃ / min to 800℃ and held for 4 h, before being allowed to cool naturally to room temperature. 5 g of the carbonized product was then heated to 450℃ in a carbon dioxide atmosphere at a rate of 3℃ / min and held for 1 h, followed by a rate of 5℃ / min to 870℃ and held for 8 h, with a gas flow rate of 3 mL / min. The specific surface area of ​​the activated sample was determined to be 1514 m². 2 / g, total pore volume 0.724cm³ 3 / g, with an average pore size of 1.71nm. The activated product was used to prepare a supercapacitor with an initial specific capacitance of 180.2F / g and a capacitance retention of 91.0% after 100 cycles.

[0047] Example 3

[0048] Take appropriate amounts of camphor wood and petroleum coke, crush them separately using a crusher, and screen them through a 5000-mesh sieve. Take the powder passing through the sieve and dry it at 100℃ for 18 hours. Take 50g of camphor wood powder, 200g of petroleum coke powder, 15g of hexamethylenetetramine, 5g of melamine, 18g of alcohol ether carboxylate AEC-9Na, and 600mL of water in a flask, and stir at 90℃ for 8 hours at a stirring speed of 300rpm. After the reaction is complete, filter and dry the resulting solid product in an oven at 80℃ for 12 hours.

[0049] The product was then heated to 150℃ in a nitrogen atmosphere at a rate of 3℃ / min and held for 30 min, followed by a rate of 1℃ / min to 400℃ and a holding time of 1.5 h, and then a rate of 5℃ / min to 850℃ and a holding time of 4 h, before being allowed to cool naturally to room temperature. 5 g of the carbonized product was then heated to 450℃ in a carbon dioxide atmosphere at a rate of 3℃ / min and held for 1 h, followed by a rate of 5℃ / min to 850℃ and a holding time of 8 h, with a gas flow rate of 3 mL / min. The specific surface area of ​​the activated sample was measured to be 2019 m². 2 / g, total pore volume 0.983cm³ 3 / g, average pore size 2.14nm. The activated product adsorbed Cd. 2+ The initial adsorption rate reached 94%, and the adsorption rate remained at 87% after 10 cycles.

[0050] Example 4

[0051] Take appropriate amounts of bamboo and petroleum coke, crush them separately using a crusher, and sieve them through a 5000-mesh screen. Dry the powder passing through the sieve at 100℃ for 18 hours. Take 30g of bamboo powder, 150g of petroleum coke powder, 10g of hexamethylenetetramine, 5g of melamine, 11g of alcohol ether carboxylate AEC-9Na, and 600mL of water in a flask. Stir at 90℃ for 8 hours at a stirring speed of 400rpm. After the reaction is complete, filter and dry the resulting solid product in an oven at 80℃ for 12 hours.

[0052] The product was then heated to 150℃ in a nitrogen atmosphere at a rate of 3℃ / min and held for 30 min, followed by a rate of 1℃ / min to 400℃ and held for 1.5 h, and then a rate of 5℃ / min to 850℃ and held for 4 h, before being allowed to cool naturally to room temperature. 5 g of the carbonized product was then heated to 450℃ in a carbon dioxide atmosphere at a rate of 3℃ / min and held for 1 h, followed by a rate of 5℃ / min to 830℃ and held for 8 h, with a gas flow rate of 3 mL / min. The specific surface area of ​​the activated sample was determined to be 1994 m². 2 / g, total pore volume 0.961cm³ 3 / g, average pore size 2.253nm. The activated product adsorbed Cd. 2+ The initial adsorption rate reached 93%, and the adsorption rate remained at 88% after 10 cycles.

Claims

1. A method for preparing porous carbon materials using petroleum coke and biomass as raw materials, characterized in that... The following technical solutions will be adopted for implementation: (1) Pretreatment of biomass: The biomass raw material is crushed to a particle size of 2-3 μm and then dried at 90-100℃ for 17-19h to obtain fine dry biomass powder; the biomass includes any one or a mixture of two or more of coconut shell, straw, rice husk, wood, bamboo, sugarcane bagasse, nut shell, wheat starch, and corn starch. (2) Pretreatment of petroleum coke: The petroleum coke raw material is crushed to a particle size of 2-3 μm, and then dried at 90-100℃ for 17-19h to obtain petroleum coke fine powder dry material; (3) Raw material mixing and reaction curing: Biomass fine powder dry material and petroleum coke fine powder dry material are added to the reactor along with hexamethylenetetramine, melamine, alcohol ether carboxylate and water in a mass ratio of (70-110):(90-150):(6-12):(2-3):(4-9):(450-600) and stirred for 4.5-6 hours. The temperature inside the reactor is controlled at 86-95℃. After the reaction is completed, the reaction product is filtered to obtain semi-dry material, which is then dried at 65-75℃ for 11-13 hours to obtain the cured product. (4) Carbonization treatment: The cured product obtained in step (3) is fed into a tube furnace and heat-treated under a nitrogen atmosphere. The heat treatment is carried out in three stages: ① First, the temperature is raised to 140-180℃ at 2-4℃ / min and held for 25-40min; ② Then, the temperature is raised to 360-450℃ at 0.8-1.5℃ / min and held for 1.2-1.9h; ③ Then, the temperature is raised to 780-830℃ at 4-6℃ / min and held for 3.6-5h to carry out the carbonization reaction and obtain the carbonized product. (5) Activation treatment: The carbonized product obtained in step (4) is heated to 840℃-890℃ in a tube furnace and activated for 7-9 hours in a carbon dioxide atmosphere to obtain a specific surface area of ​​1510-1630 m². 2 / g, total pore volume 0.72-0.79cm³ 3 Porous carbon material with an average pore size of 1.71-1.85 nm per g, used for fabricating supercapacitors.

2. A method for preparing porous carbon materials using petroleum coke and biomass as raw materials, characterized in that... The following technical solutions will be adopted for implementation: (1) Pretreatment of biomass: The biomass raw material is crushed to a particle size of 2-3 μm and then dried at 90-100℃ for 17-19h to obtain fine dry biomass powder; the biomass includes any one or a mixture of two or more of coconut shell, straw, rice husk, wood, bamboo, sugarcane bagasse, nut shell, wheat starch, and corn starch. (2) Pretreatment of petroleum coke: The petroleum coke raw material is crushed to a particle size of 2-3 μm, and then dried at 90-100℃ for 17-19h to obtain petroleum coke fine powder dry material; (3) Raw material mixing and reaction curing: Biomass fine powder dry material and petroleum coke fine powder dry material are added to the reactor along with hexamethylenetetramine, melamine, alcohol ether carboxylate and water in a mass ratio of (50-70):(180-280):(12-22):(4-11):(17-21):(900-1000) and stirred and mixed. The reaction is carried out for 7.5-8.5 hours, and the temperature inside the reactor is controlled at 86-95℃. After the reaction is completed, the reaction product is filtered to obtain semi-dry material, and then the semi-dry material is dried at 75-85℃ for 11-13 hours to obtain the cured product. (4) Carbonization treatment: The cured product obtained in step (3) is fed into a tube furnace and heat-treated under a nitrogen atmosphere. The heat treatment is carried out in three stages: ① First, the temperature is raised to 140-180℃ at 2-4℃ / min and held for 25-40min; ② Then, the temperature is raised to 360-450℃ at 0.8-1.5℃ / min and held for 1.2-1.9h; ③ Then, the temperature is raised to 830-870℃ at 4-6℃ / min and held for 3.6-5h to carry out the carbonization reaction and obtain the carbonized product. (5) Activation treatment: The carbonized product obtained in step (4) is heated to 830℃-850℃ in a tube furnace and activated for 7-9 hours in a carbon dioxide atmosphere to obtain a specific surface area of ​​1950-2090 m². 2 / g, total pore volume 0.96-0.99cm³ 3 Porous carbon materials with an average pore size of 2.11-2.29 nm and a g / g, used for adsorbing heavy metal ions in wastewater.

3. A method for preparing porous carbon materials using petroleum coke and biomass as raw materials as described in claim 1 or 2, characterized in that: In step (3), the stirring speed in the reactor is controlled at 200-600 rpm, and the reaction time is controlled at 5-10 h.