Coal-based activated carbon and its preparation method and application

Abstract

The present invention discloses a coal-based activated carbon and a preparation method thereof. The preparation method of the coal-based activated carbon includes: selecting one or more raw coals as the feed coal, the raw coals including bituminous coal and anthracite, the bituminous coal including No. 1 coal, No. 2 coal, and No. 3 coal, and the anthracite being No. 4 coal; taking the total mass of the No. 1 coal as 100%, the moisture content of the No. 1 coal is less than 12%, the ash content is less than 5%, and the volatile matter content is less than 34%; taking the total mass of the No. 2 coal as 100%, the moisture content of the No. 2 coal is less than 15%, the ash content is less than 3.5%, and the volatile matter content is less than 40%; taking the total mass of the No. 3 coal as 100%, the moisture content of the No. 3 coal is less than 10%, the ash content is less than 1.8%, and the volatile matter content is less than 42%; taking the total mass of the No. 4 coal as 100%, the moisture content of the No. 4 coal is less than 4%, the ash content is less than 5%, and the volatile matter content is less than 9%; the coal-based activated carbon is obtained after the feed coal is crushed, carbonized, and activated. The preparation method of the coal-based activated carbon for efficiently adsorbing VOCs of the present invention fully considers different properties of the coal-based activated carbon, such as iodine adsorption value, ash content, specific surface area, total pore volume, pore diameter, VOC adsorbate, and saturated adsorption capacity. The prepared activated carbon can effectively adsorb VOCs and is expected to provide strong support for the purification and treatment of the air in the passenger compartments of rail transit.

Description

Technical Field

[0001] The invention belongs to the technical field of rail transit passenger compartment air purification, and specifically relates to a method for preparing coal-based activated carbon for efficiently absorbing VOCs. Background Art

[0002] The World Health Organization points out that long-term living or working in air containing volatile organic compounds (VOCs) will show a variety of pathological reactions, and even develop serious diseases such as leukemia and cancer. At present, rail transit vehicles are also facing the problem of excessive VOCs content in the passenger compartment, which seriously affects the physical and mental health of passengers and the brand image of China's rail transit vehicles.

[0003] Activated carbon is a porous carbon material with a well-developed pore structure, certain mechanical strength and huge specific surface area. It has strong adsorption performance and can selectively remove certain impurities or components in the liquid or gas phase. At present, indoor VOCs emission reduction and air purification mainly use activated carbon adsorption materials for physical or chemical adsorption. The disadvantage is that due to poor adsorption capacity, the adsorption material will quickly reach saturation and release secondary substances, resulting in more serious pollution problems.

[0004] In view of the characteristics and difficulties in the field of VOCs emission reduction and air purification, it is urgent to develop a coal-based activated carbon with a VOCs purification rate of more than 90%, making it a green material with efficient VOCs adsorption and purification capabilities. Summary of the invention

[0005] The purpose of the present invention is to prepare coal-based activated carbon with high efficiency in adsorbing VOCs, to provide a more effective adsorbent for purifying VOCs in rail transit passenger compartment air, thereby improving the air quality in the passenger compartment and ensuring a good riding experience for passengers.

[0006] In one aspect, the present invention provides a method for preparing coal-based activated carbon, comprising: selecting one or more raw coals as raw coals, wherein the raw coals include bituminous coal and anthracite, wherein the bituminous coal includes 1 # Coal, 2 # Coal, 3 # Coal, the anthracite is 4 # Coal; # The total mass of coal is 100%, and the 1 # The moisture content of coal is less than 12%, the ash content is less than 5%, and the volatile content is less than 34%; # The total mass of coal is 100%, and the 2 # The moisture content of coal is less than 15%, the ash content is less than 3.5%, and the volatile content is less than 40%; # The total mass of coal is 100%, and the 3 #The moisture content of coal is less than 10%, the ash content is less than 1.8%, and the volatile content is less than 42%; # The total mass of coal is 100%, and the 4 # The moisture content of coal is less than 4%, the ash content is less than 5%, and the volatile content is less than 9%; the coal-based activated carbon is obtained after the raw coal is crushed, carbonized and activated.

[0007] According to one embodiment of the present invention, when the raw coal includes multiple raw coals, the raw coal is crushed to have a pass rate of more than 90% on a 200-mesh sieve; when the raw coal is one type of raw coal, the raw coal is crushed to a particle size of 8-30 mesh.

[0008] According to another embodiment of the present invention, the raw coal comprises 2 # Coal and 3 # Coal, 2 # Coal and the 3 # The mass ratio of the coal is 1-3:0.5-1.5; or the raw coal includes the bituminous coal and the anthracite, the mass ratio of the bituminous coal to the anthracite is 0.75-1.25:3-5, and the bituminous coal is 1 # Coal, 2 # Coal and the 3 # One or more types of coal, when the bituminous coal includes multiple types, any ratio of the multiple types.

[0009] According to another embodiment of the present invention, the final carbonization temperature is controlled at 500-600°C.

[0010] According to another embodiment of the present invention, the activation adopts a steam activation method, the activation temperature is controlled at 900-940° C., the activation time is controlled at 2.5-3.5 h, and the amount of activator is 1.0-1.5 mL / (100 g·min).

[0011] According to another embodiment of the present invention, the coal-based activated carbon has an iodine adsorption value greater than 1000 mg / g and a specific surface area greater than 1100 m 2 / g, pore diameter is 1.8-2.2nm, and total pore volume is 0.4-0.65cm 3 / g.

[0012] Another aspect of the present invention provides a method for preparing coal-based activated carbon by the above method.

[0013] Another aspect of the present invention further provides a use of the above-mentioned coal-based activated carbon in the adsorption of volatile organic compounds.

[0014] According to one embodiment of the present invention, the pore size of the coal-based activated carbon is 2 to 4 times the diameter of the volatile organic compound molecules to be adsorbed, so as to ensure that the organic compound molecules can easily enter the activated carbon pores and be adsorbed by them.

[0015] The present invention provides a method for preparing coal-based activated carbon with high efficiency in adsorbing VOCs, which fully considers the different properties of coal-based activated carbon, such as iodine adsorption value, ash content, specific surface area, total pore volume, pore size, VOC adsorbent and saturated adsorption capacity. The prepared activated carbon can effectively adsorb VOCs, and is expected to provide strong support for the purification and management of rail transit passenger compartment air. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of a process of one embodiment of the present invention.

[0017] Figure 2 It is a schematic diagram of a process of another embodiment of the present invention.

[0018] Figure 3 It is a flow chart of another embodiment of the present invention. DETAILED DESCRIPTION

[0019] The present invention is described in detail below in conjunction with specific implementation modes.

[0020] The method for preparing coal-based activated carbon of the present invention comprises: selecting one or more raw coals as raw coals, the raw coals comprising bituminous coal and anthracite, the bituminous coal comprising 1 # Coal, 2 # Coal, 3 # Coal, anthracite is 4 # Coal; 1 # The total mass of coal is 100%, 1 # The moisture content of coal is less than 12%, the ash content is less than 5%, and the volatile content is less than 34%; # The total mass of coal is 100%, 2 # The moisture content of coal is less than 15%, the ash content is less than 3.5%, and the volatile content is less than 40%; # The total mass of coal is 100%, 3 # The moisture content of coal is less than 10%, the ash content is less than 1.8%, and the volatile content is less than 42%; # The total mass of coal is 100%, 4 # The moisture content of coal is less than 4%, the ash content is less than 5%, and the volatile content is less than 9%; the raw coal is crushed, carbonized and activated to obtain coal-based activated carbon. The present invention can prepare coal-based activated carbon that effectively adsorbs VOCs by controlling the moisture, ash and volatile content of the raw coal.

[0021] The method of the present invention is applicable to any process for preparing coal-based activated carbon, such as but not limited to briquetting process, raw coal crushing process and column carbon process, etc. The above three processes are taken as examples below, but the present invention is not limited to the above three processes.

[0022] like Figure 1 As shown, coal-based activated carbon is prepared by briquetting. First, several raw coals that meet the conditions for preparing activated carbon are screened, and the raw coals are mixed in proportion to form raw coal. The raw coal is ground to obtain coal powder of a certain fineness for molding, granulation, carbonization, activation, and finally finished activated carbon. The raw coal is crushed to a pass rate of more than 90% on a 200-mesh sieve to ensure that the raw coal is fully mixed. Preferably, the raw coal includes 2 # Coal and 3 # Coal, 2 # and 3 # The mass ratio is 1-3:0.5-1.5.

[0023] like Figure 2 As shown, the raw coal crushing process is used to prepare coal-based activated carbon. A single raw coal is selected for crushing, carbonization, activation, and finally made into finished activated carbon. The raw coal is crushed into a particle size of 8-30 mesh. The preferred raw coal is 1 # coal.

[0024] like Figure 3 As shown, the column carbon process is used to prepare coal-based activated carbon. First, several raw coals that meet the conditions for preparing activated carbon are screened, the raw coals are mixed in proportion to form raw coal, the raw coal is ground to obtain coal powder of a certain fineness, a binder is added to the coal powder for molding, and then the raw coal is granulated, carbonized, and activated to finally make finished activated carbon. The raw coal is crushed to a pass rate of more than 90% on a 200-mesh sieve to ensure sufficient mixing of the raw coal. Preferably, the raw coal includes bituminous coal and anthracite, and the mass ratio of bituminous coal to anthracite is 0.75-1.25:3-5. Bituminous coal is 1 # , 2 # and 3 # One or more types of coal. When bituminous coal includes multiple types, it can be any ratio of the multiple types.

[0025] In an optional embodiment, the final carbonization temperature is controlled at 500-600°C.

[0026] In an optional embodiment, the activation method is steam activation, the activation temperature is controlled at 900-940°C, the activation time is controlled at 2.5-3.5h, the amount of activator is 1.0-1.5mL / (100g·min), and the total pore volume is 0.4-0.65cm 3 / g.

[0027] The iodine adsorption value of the finally prepared coal-based activated carbon is greater than 1000 mg / g, and the specific surface area is greater than 1100 m 2 / g, pore size is 1.8~2.2nm.

[0028] The raw coal used in the method of the present invention may be selected from one or more of bituminous coal and anthracite.

[0029] The coal-based activated carbon prepared by the method of the present invention is suitable for adsorbing volatile organic compounds.

[0030] In an optional embodiment, in order to ensure that the organic compound molecules can easily enter the activated carbon pores and be adsorbed by them, the pore size of the coal-based activated carbon is 2 to 4 times the diameter of the volatile organic compound molecules to be adsorbed. The diameters of the main organic pollutant molecules are shown in Table 1. In addition, the prepared activated carbon was tested for VOCs adsorption capacity, and the adsorption capacity of the main pollutant toluene was greater than 380 mg / g.

[0031] Table 1: Diameters of main organic pollutant molecules (unit: nm)

[0032]

[0033] The coal-based activated carbon prepared by the present invention can effectively adsorb VOCs, and plays a good role in improving the air quality in rail transit passenger compartments and enhancing the riding experience of passengers.

[0034] The present invention is further described below by specific examples. However, these examples are merely exemplary and do not constitute any limitation to the protection scope of the present invention.

[0035] In the following examples and comparative examples, the reagents, materials and instruments used are all commercially available unless otherwise specified.

[0036] The following examples are selected from the four types of coal shown in Table 2.

[0037] Table 2: Control standards and measured values ​​of moisture, ash and volatile matter of different coal sources.

[0038]

[0039]

[0040] Example 1

[0041] The coal-based activated carbon for adsorbing VOCs in this embodiment is composed of Figure 1 Preparation of briquette activated carbon process, during preparation, control 2 # Coal: 3 # Coal = 2:1, the final carbonization temperature is 550℃, the activation temperature is 900℃, the activation time is 3.0h, the activator dosage is 1.25mL / (100g·min), the activated carbon particle size is 8*30 mesh, and its performance test is shown in Table 3.

[0042] Example 2

[0043] The coal-based activated carbon for adsorbing VOCs in this embodiment is composed of Figure 2 The raw coal is crushed to produce activated carbon. During the preparation, the raw coal is a single 1 # Coal, the final carbonization temperature is 530℃, the activation temperature is 920℃, the activation time is 2.5h, the activator dosage is 1.25mL / (100g·min), the activated carbon particle size is 8*30 mesh, and its performance test is shown in Table 3.

[0044] Example 3

[0045] The coal-based activated carbon for adsorbing VOCs in this embodiment is composed of Figure 3 Preparation of columnar activated carbon process, during preparation, control 4 # Coal: 1 # Coal = 4:1, the binder is a mixture of high-temperature coal tar and water, the addition amounts of coal tar and water are 10% and 20% of the total coal powder respectively, the final carbonization temperature is 570°C, the activation temperature is 900°C, the activation time is 3.5h, the amount of activator is 1.25mL / (100g·min), the diameter of the prepared columnar activated carbon is 4mm, and its performance test is shown in Table 3.

[0046] Table 3: Actual application effects of carrier activated carbon for adsorbing VOCs in Examples 1 to 3.

[0047]

[0048]

[0049] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for preparing coal-based activated carbon, characterized in that: include: Select a variety of raw coal as raw coal, the raw coal is bituminous coal, the bituminous coal is 2 # Coal and 3 # Coal; # The total mass of coal is 100%, and the 2 # The moisture content of coal is less than 15%, the ash content is less than 3.5%, and the volatile content is less than 40%; # The total mass of coal is 100%, and the 3 # The moisture content of the coal is less than 10%, the ash content is less than 1.8%, and the volatile content is less than 42%; # Coal and the 3 # The mass ratio of coal is 1-3:0.5-1.5; The coal-based activated carbon is obtained by crushing, carbonizing and activating the raw coal; wherein the raw coal is crushed to have a passing rate of greater than 90% on a 200-mesh sieve; The final carbonization temperature is controlled at 500-600°C; The activation adopts a water vapor activation method, the activation temperature is controlled at 900-940°C, the activation time is controlled at 2.5-3.5h, and the amount of the activator is 1.0-1.5mL / (100g·min); The iodine adsorption value of the coal-based activated carbon is greater than 1000 mg / g, and the specific surface area is greater than 1100 m 2 / g, pore diameter is 1.8-2.2nm, and total pore volume is 0.4-0.65cm 3 / g.

2. A coal-based activated carbon, characterized in that: Prepared by the preparation method described in claim 1.

3. Use of the coal-based activated carbon according to claim 2 in the adsorption of volatile organic compounds.

4. The use according to claim 3, characterized in that: The pore size of the coal-based activated carbon is 2 to 4 times the molecular diameter of the volatile organic compound to be adsorbed, so as to ensure that the organic compound molecules can easily enter the activated carbon pores and be adsorbed by them.

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