Camellia oleifera shell-based columnar activated carbon and preparation method thereof

Abstract

The invention relates to the field of activated carbon preparation, in particular to camellia oleifera shell-based columnar activated carbon and a preparation method thereof. Comprising the following steps: (1) pretreatment: pretreating camellia oleifera shells through a converter; (2) powder preparation: directly preparing powder from the pretreated camellia oleifera shells, or preparing powder from the pretreated camellia oleifera shells together with a reinforcing agent; (3) molding: sequentially adding the powder, a binder and water into a kneading machine, and uniformly stirring and molding; (4) carbonizing, namely adding the molded material into a converter for carbonizing; (5) activation: adding the carbonized material into a converter for activation; and (6) post-treatment: cooling the activated material discharged from the converter, screening, and removing powder generated in the preparation process to obtain the columnar activated carbon. According to the preparation method, the strength of the granular activated carbon is improved, and aiming at the problem of low strength of the crushed granular activated carbon, the cold-state strength of a formed sample is ensured and the strength of the sample subjected to subsequent high-temperature treatment is ensured by optimizing the process and the proportion, so that the application field of the activated carbon is widened.

Description

Technical Field

[0001] The invention relates to the field of activated carbon preparation, and in particular to camellia oleifera shell-based columnar activated carbon and a preparation method thereof. Background Art

[0002] Camellia oleifera is a woody oil tree species unique to southern China. It is one of the four major woody edible oil tree species in the world. It is naturally distributed in 15 provinces and regions in the south, with an area of ​​more than 70 million mu. The main production areas are in Hunan, Jiangxi, Guangxi, Hubei, and Guangdong. According to the planning of the National Forestry and Grassland Administration for the camellia oil industry, by 2025, the planting area of ​​camellia oleifera in my country will reach 90 million mu. Camellia oil is the common name for camellia oil seeds. It is a pure natural high-quality edible vegetable oil extracted from the mature seeds of ordinary camellia oil. In 2021, my country's camellia oil production was about 1.009 million tons, which has become one of the top ten oil species consumed in my country. According to the "Forest and Grassland Industry Development Plan <2021-2025>" issued by the National Forestry and Grassland Administration, by 2025, the annual output of camellia oil will reach 2 million tons. On the one hand, camellia oil is a plant edible oil strongly advocated and promoted in the "Outline of China's Edible Oil Structural Reform and Development Plan", and it is also the first health care plant edible oil recommended by the International Food and Oil Organization; it can also be used as a lubricant and anti-rust oil for industry. On the other hand, the development has also brought new problems, that is, the production of a large number of camellia shells. Camellia shells are the outer skin of camellia fruit, accounting for 60% of the entire camellia fruit. There are millions of tons of camellia shells produced each year, and the resources are quite abundant. However, at present, in addition to being used to prepare xylose, furfural and as fuel, camellia shells have not been fully developed and utilized, and a large number of camellia shells are discarded and piled up or directly burned every year, which not only occupies a large amount of land, but also causes serious environmental pollution.

[0003] Activated carbon is a carbonaceous adsorption material with a developed pore structure and a large specific surface area. It has the characteristics of strong adsorption capacity, high mechanical strength, good chemical stability and easy regeneration. It is widely used in industry, agriculture, national defense, environmental protection and other fields. The raw materials for the preparation of traditional activated carbon are mainly coal and wood. Due to the limited domestic forest resources, the decreasing coal and the high price, and the impact of environmental protection, seeking cheap and abundant renewable raw materials is an urgent problem to be solved in the field of activated carbon preparation. At present, the research on activated carbon from camellia shells in China is mainly in powder and crushed granules, which have the problems of non-renewability and low strength. Summary of the invention

[0004] The invention overcomes the deficiencies of the prior art and provides a method for preparing camellia oleifera shell-based columnar activated carbon.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0006] A method for preparing camellia oleifera shell-based columnar activated carbon comprises the following steps:

[0007] (1) pretreatment, wherein the oil tea shell is pretreated by a converter to remove some volatile substances in the raw material;

[0008] (2) Powdering: directly powdering the pretreated camellia oleifera shells, or adding a reinforcing agent to powder, wherein the powder fineness is required to pass 200 mesh> 95%;

[0009] (3) forming, adding the powder, binder and water into a kneader in sequence and stirring them evenly to form the mixture, wherein the binder is at least one of organic polymer compounds;

[0010] (4) Carbonization: adding the formed molding material into a converter for carbonization;

[0011] (5) Activation: adding the carbonized material into the converter for activation;

[0012] (6) Post-treatment: The activated material from the converter is cooled and sieved to remove the powder produced during the preparation process, resulting in columnar activated carbon.

[0013] As a further limitation of the technical solution of the present invention, the pretreatment conditions in the converter in step (1) are staged treatment at 200° C.-500° C., and the treatment time is 10-40 minutes.

[0014] As a further limitation of the technical solution of the present invention, the reinforcing agent in step (2) is at least one of asphalt, anthracite and bituminous coal, and the reinforcing agent accounts for 0-80% of the total amount of the powder.

[0015] As a further limitation of the technical solution of the present invention, the organic polymer compound in step (3) is potato flour or molasses residue.

[0016] As a further limitation of the technical solution of the present invention, in step (3), the amount of binder added is 10-60% of the mass of the powder, and the amount of water added is 10-50% of the mass of the powder.

[0017] As a further limitation of the technical solution of the present invention, in step (4), the carbonization temperature is 200-600° C., carried out from low to high, and the carbonization time is 20-60 minutes.

[0018] As a further limitation of the technical solution of the present invention, in step (5), the activation temperature is 750-950° C., and the activation time is 60-120 minutes under the action of water vapor.

[0019] In addition, the present invention also provides camellia oleifera shell-based columnar activated carbon obtained by the above preparation method.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] In view of the difficulty in regenerating powdered activated carbon, the present invention prepares columnar activated carbon by adding a tar-free binder. On the one hand, it reduces the damage to the environment and human body caused by storage, transportation and use when tar is used as a binder, thereby reducing environmentally friendly production costs; on the other hand, it facilitates the regeneration and reuse of materials.

[0022] The preparation method of the present invention improves the strength of granular activated carbon. Aiming at the problem of low strength of crushed granular activated carbon, the process and ratio are optimized to ensure the cold strength of the formed sample on the one hand, and the strength of the sample after subsequent high-temperature treatment on the other hand, thereby broadening the application field of activated carbon.

[0023] The activated carbon prepared by the present invention has a columnar shape with a diameter of 0.9-10.0 mm, has no cracks on the surface of the sample, has high strength, and is convenient for the recovery and regeneration of the adsorption material. DETAILED DESCRIPTION

[0024] The present invention is further described below in conjunction with specific embodiments.

[0025] Example 1

[0026] A method for preparing camellia oleifera shell-based columnar activated carbon comprises the following steps:

[0027] (1) Pretreatment

[0028] The oil tea shell is pretreated by a converter. The purpose of the pretreatment is to remove some volatile substances in the raw materials to facilitate the subsequent powder making. The treatment conditions are 200℃-500℃ stage treatment, and the treatment time is 10-40 minutes, specifically: stay in the 200℃ temperature section for 10 minutes, stay in the 300℃ temperature section for 10 minutes, and stay in the 400℃ temperature section for 10 minutes.

[0029] (2) Flour milling

[0030] Directly powdering the pretreated camellia oleifera shells requires that the powder fineness should pass 200 mesh> 95%.

[0031] (3) Molding

[0032] Add powder, binder and water into a kneader in sequence and stir evenly, the binder is added in a proportion of 10% and the water is added in a proportion of 20%. The binder is potato flour.

[0033] (4) Carbonization

[0034] The formed molding material is added into the converter for carbonization at a carbonization temperature of 200-600°C, from low to high, and the carbonization time is 20-60 minutes, specifically: stay in the 250°C temperature section for 15 minutes, stay in the 375°C temperature section for 15 minutes, and stay in the 500°C temperature section for 15 minutes.

[0035] (5) Activation

[0036] The carbonized material is added into the converter for activation at a temperature of 900°C and under the action of water vapor for 90 minutes.

[0037] (6) Post-processing

[0038] The activated material coming out of the converter is cooled and sieved to remove the powder produced during the preparation process, which is columnar activated carbon.

[0039] Example 2

[0040] A method for preparing camellia oleifera shell-based columnar activated carbon comprises the following steps:

[0041] (1) Pretreatment

[0042] The oil tea shell is pretreated by a converter. The purpose of the pretreatment is to remove some volatile substances in the raw materials to facilitate the subsequent powder making. The treatment conditions are 200℃-500℃ stage treatment, and the treatment time is 10-40 minutes, specifically: stay in the 200℃ temperature section for 7 minutes, stay in the 350℃ temperature section for 7 minutes, and stay in the 450℃ temperature section for 7 minutes.

[0043] (2) Flour milling

[0044] The pretreated oil-tea camellia shells are mixed with anthracite as a reinforcing agent for powder making, and the powder fineness is required to pass 200 mesh> 95%.

[0045] (3) Molding

[0046] Add powder, binder and water into a kneader in sequence and stir evenly, the binder adding ratio is 60%, and the water adding ratio is 30%. The binder is molasses residue.

[0047] (4) Carbonization

[0048] The formed material is added to the converter for carbonization at a temperature of 200-600°C, from low to high, for a carbonization time of 20-60 minutes, specifically: the carbonization time is 20-60 minutes. Stay in the 250°C temperature section for 10 minutes, the 375°C temperature section for 10 minutes, and the 500°C temperature section for 10 minutes.

[0049] (5) Activation

[0050] The carbonized material is added into the converter for activation at a temperature of 850°C and under the action of water vapor for 100 minutes.

[0051] (6) Post-processing

[0052] The activated material coming out of the converter is cooled and sieved to remove the powder produced during the preparation process, which is columnar activated carbon.

[0053] Example 3

[0054] A method for preparing camellia oleifera shell-based columnar activated carbon comprises the following steps:

[0055] (1) Pretreatment

[0056] The oil tea shell is pretreated by a converter. The purpose of the pretreatment is to remove some volatile substances in the raw materials to facilitate the subsequent powder making. The treatment conditions are 200℃-500℃ stage treatment, and the treatment time is 10-40 minutes, specifically: stay in the 250℃ temperature section for 5 minutes, stay in the 350℃ temperature section for 5 minutes, and stay in the 450℃ temperature section for 5 minutes.

[0057] (2) Flour milling

[0058] The pretreated camellia oleifera shell is mixed with reinforcing agent asphalt for powdering, and the powder fineness is required to pass 200 mesh> 95%.

[0059] (3) Molding

[0060] Add powder, binder and water into a kneader in sequence and mix them evenly. The adding ratio of binder is 10%, the adding ratio of water is 50%, and the binder is potato flour.

[0061] (4) Carbonization

[0062] The formed material is added to the converter for carbonization at a temperature of 200-600°C, from low to high, for a carbonization time of 20-60 minutes, specifically: the carbonization time is 20-60 minutes. Stay in the 250°C temperature section for 10 minutes, the 450°C temperature section for 10 minutes, and the 550°C temperature section for 10 minutes.

[0063] (5) Activation

[0064] The carbonized material is added into the converter for activation at a temperature of 900°C and under the action of water vapor for a time of 105 minutes.

[0065] (6) Post-processing

[0066] The activated material coming out of the converter is cooled and sieved to remove the powder produced during the preparation process, which is columnar activated carbon.

[0067] The camellia oleifera shell-based columnar activated carbon prepared in Examples 1-3 and the existing camellia oleifera shell granular activated carbon were subjected to strength tests, and the results are shown in the following table:

[0068] It can be seen from the table below that the columnar activated carbon prepared by the method of the present invention is higher than the granular activated carbon.

[0069]

Claims

1. A method for preparing camellia oleifera shell-based columnar activated carbon, characterized in that: The following steps are involved: (1) Pretreatment: The oil tea shells are pretreated by a converter to remove some volatile substances in the raw materials; (2) Powdering: Powdering the pretreated camellia oleifera shells directly, or adding a reinforcing agent for powdering, with the requirement that the powder fineness should be greater than 95% with a 200-mesh passing rate; (3) forming, adding the powder, binder and water into a kneader in sequence and stirring them evenly to form the mixture, wherein the binder is at least one organic polymer compound; (4) Carbonization: adding the formed material into the converter for carbonization; (5) Activation: adding the carbonized material into the converter for activation; (6) Post-treatment: The activated material from the converter is cooled and sieved to remove the powder produced during the preparation process, resulting in columnar activated carbon.

2. The method for preparing a camellia oleifera shell-based columnar activated carbon according to claim 1, characterized in that: The pretreatment condition in the converter in step (1) is 200°C-500°C stage-by-stage treatment, and the treatment time is 10-40 minutes.

3. The method for preparing a camellia oleifera shell-based columnar activated carbon according to claim 1, characterized in that: The reinforcing agent in step (2) is at least one of asphalt, anthracite and bituminous coal; the reinforcing agent accounts for 0-80% of the total amount of the powder.

4. The method for preparing a camellia oleifera shell-based columnar activated carbon according to claim 1, characterized in that: In step (3), the organic polymer compound is potato flour or molasses residue.

5. The method for preparing a camellia oleifera shell-based columnar activated carbon according to claim 1, characterized in that: In step (3), the amount of binder added is 10-60% of the mass of the powder, and the amount of water added is 10-50% of the mass of the powder.

6. The method for preparing a camellia oleifera shell-based columnar activated carbon according to claim 1, characterized in that: In step (4), the carbonization temperature is 200-600°C, from low to high, and the carbonization time is 20-60 minutes.

7. The method for preparing camellia oleifera shell-based columnar activated carbon according to claim 1, characterized in that: In step (5), the activation temperature is 750-950°C, and the activation time is 60-120 minutes under the action of water vapor.

8. Camellia oleifera shell-based columnar activated carbon obtained according to the preparation method described in claims 1-7.

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