Process for producing activated carbon by utilizing gasified fine slag

Abstract

The invention provides a process for producing activated carbon by utilizing gasified fine slag, and relates to the technical field of activated carbon extraction. The process for producing the activated carbon by utilizing the gasified fine slag comprises the following steps: screening and washing to wash away internal silt and ash; acid pickling is conducted, calcium oxide in the micropores is removed, part of calcium carbonate is decomposed into calcium oxide in the combustion process in the gasification furnace, and undecomposed calcium carbonate is deposited in the fine slag micropores; fine slag obtained after flushing and acid pickling enters a 200-mesh washing device, the pH value of washing is close to neutral, and then the next procedure is carried out; alkali washing is conducted, and silicon dioxide, coal tar and organic matter adsorbed in a settling tank which are left in fine slag micropores in the combustion process are removed; and washing, repeating the steps, and entering the next process when the pH value of water washing is close to neutral. The activated carbon is produced by using the fine slag, so that the landfill cost of enterprises is reduced, the consumption of coal for producing the activated carbon is saved, the pressure of a landfill site is reduced, and considerable economic benefits and good social benefits are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of activated carbon extraction, in particular to a process for producing activated carbon by utilizing gasified fine slag. Background Art

[0002] Coal gasification to produce hydrogen and carbon monoxide is the most basic process of coal chemical industry. With the development of coal chemical industry, the output of gasification waste slag is increasing (fine slag with a water content of 60%-70%, methanol produces about 0.13 tons). Due to the large amount of slag produced, the landfill costs generated have caused great economic losses to the company. At the same time, due to the large amount of slag produced, the landfill site must have a large enough capacity, which has caused great environmental pressure on the society. The use of fine slag to produce activated carbon not only reduces the company's landfill costs (60-70 yuan per ton), but also saves the consumption of coal in the production of activated carbon, and also reduces the pressure on the landfill site, which has considerable economic benefits and good social benefits.

[0003] Coal slurry or coal powder burns in a gasifier at a high temperature of 1300 degrees. Some of the fine coal particles that are not completely burned become active porous coal particles. Due to their low density, they flow into the sedimentation tank with the washing water, adsorb impurities in the sedimentation tank and settle to the bottom of the tank. They are pumped into the negative pressure dehydration system. The dehydrated coal ash (water content of 60%-70%) is the gasification waste slag.

[0004] However, the existing extraction process still has some shortcomings and areas for improvement in actual use. The traditional activated carbon production method is inefficient, has a long production cycle, and has limited output. At the same time, the existing production process is complex and difficult to operate. Therefore, technicians in this field provide an activated carbon production process using gasified fine slag to solve the problems raised in the above background technology. Summary of the invention

[0005] 1. Technical issues to be solved

[0006] In view of the shortcomings of the prior art, the present invention provides a process for producing activated carbon using gasified fine slag, which solves the problems of low efficiency, long production cycle and complex and difficult process in the existing preparation process.

[0007] (II) Technical solution

[0008] To achieve the above objectives, the present invention is implemented through the following technical solutions: A process for producing activated carbon using gasified fine slag, comprising:

[0009] Screening and washing: Since the activity of activated carbon in each particle size segment is different, it is necessary to select the fine slag with the best activity and wash away the internal sand and ash;

[0010] Pickling to remove calcium oxide in the micropores. During the combustion process in the gasifier, part of the calcium carbonate is decomposed into calcium oxide and the undecomposed calcium carbonate is deposited in the micropores of the fine slag. The calcium carbonate adsorbed on the surface that is not completely washed away will affect the activity of the fine slag.

[0011] After washing, the fine residue after pickling enters the 200-mesh water washing device. The pH value of the water washing is close to neutral and enters the next process;

[0012] Dehydration, enter the dehydration device, wash with water until neutral and then dehydrate;

[0013] Alkaline washing to remove silica, coal tar and organic matter adsorbed in the sedimentation tank that remain in the micropores of fine slag during the combustion process;

[0014] Rinse and repeat the above steps. The fine residue after alkali washing enters the elution device. The pH value of water washing is close to neutral and enters the next process;

[0015] Activation: steam activation is used for activation.

[0016] Preferably, the screening water washing comprises the following steps:

[0017] S1. Raw material preparation, first collect the fine slag to be processed, and preliminarily screen the fine slag containing larger particles in the raw material to remove these particles;

[0018] S2. Screening: Select a suitable screen or screening equipment according to the required particle size, spread the fine residue evenly on the screen, and screen it by vibration and rolling. The screened fine residue is stored separately for subsequent processing or use;

[0019] S3. Washing: prepare washing equipment, ensure sufficient water flow and appropriate washing time, put the screened fine residue into the washing tank, and use running water or spraying to wash the fine residue to remove soluble impurities and dust on the surface;

[0020] S4. Separation, dehydration and drying. After washing, the fine residue is separated from the water using a screen or a centrifuge. The washed fine residue is dehydrated to reduce the moisture content, and the dehydrated fine residue is dried.

[0021] Preferably, the pickling comprises the following steps:

[0022] S1. Add 4 times the mass of hydrochloric acid solution to the inside of the fine slag, with a concentration of 0.5%-1.0%;

[0023] S2. Heat the temperature to 30 degrees Celsius to 40 degrees Celsius and stir. When the pH value no longer increases and stabilizes, the pickling is completed and the pH value is in the range of 3-4.

[0024] Preferably, the alkali washing comprises the following steps:

[0025] S1. Add the treated fine slag to the alkali washing tank and add 0.5%-1.0% sodium hydroxide solution twice the mass of the fine slag inside;

[0026] S2. Heat it to a temperature of 70-80 degrees Celsius, stir it for half an hour, wash it to the center with water and then dehydrate it. The iodine value of the product is between 580-620.

[0027] Preferably, the steam activation method comprises the following steps:

[0028] S1. Steam activation, preheating the activation furnace to the activation temperature, controlling the temperature between 700 degrees Celsius and 900 degrees Celsius, transferring the fine slag to the activation furnace, and then introducing water vapor, which reacts with the carbon on the surface of the fine slag to form a porous structure;

[0029] S2. Cooling and collection. After activation is completed, turn off the water vapor supply and allow the activated carbon to cool naturally in the activation furnace or use inert gas for cooling. The cooled activated carbon is taken out of the activation furnace for subsequent processing and storage.

[0030] (III) Beneficial effects

[0031] The present invention provides a process for producing activated carbon using gasified fine slag. It has the following beneficial effects:

[0032] 1. In the present invention, by utilizing fine slag to produce activated carbon, the landfill cost of the enterprise is reduced, the consumption of coal for producing activated carbon is saved, and the pressure on the landfill is also reduced, which has considerable economic benefits and good social benefits. DETAILED DESCRIPTION

[0033] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0034] Embodiment 1:

[0035] The embodiment of the present invention provides a process for producing activated carbon using gasified fine slag, comprising:

[0036] Screening and washing: Since the activity of activated carbon in each particle size segment is different, it is necessary to select the fine slag with the best activity and wash away the internal sand and ash;

[0037]

[0038] The activities of fine slags of different particle sizes are shown in the table above;

[0039] According to the product quality and quantity data of different particle sizes in the above table, first use the particle size of 24-30 mesh, which accounts for about 2.0%-4.5% of the dry coal slag. You can also accurately screen the particle size range according to the quality requirements of activated carbon, to fine slag between 200 mesh; rinse and screen with water on a 24-mesh screen, and the slag larger than 24 mesh, with a calorific value of about 4500-5000, is retained for recycling; the slag smaller than 24 mesh after screening enters a 200-mesh dehydration device for water washing to wash away mud and sand, fine slag particles smaller than 200 mesh, ash, insoluble salts adsorbed on the surface, soluble salts in the gaps, etc.; when the turbidity of the effluent is less than 20, the cleaning is ended and the next process is entered;

[0040] Pickling to remove calcium oxide in the micropores. During the combustion process in the gasifier, part of the calcium carbonate is decomposed into calcium oxide and the undecomposed calcium carbonate is deposited in the micropores of the fine slag. The calcium carbonate adsorbed on the surface that is not completely washed away will affect the activity of the fine slag.

[0041] After washing, the fine residue after pickling enters the 200-mesh water washing device. The pH value of the water washing is close to neutral and enters the next process;

[0042] Dehydration, enter the dehydration device, wash with water until neutral and then dehydrate;

[0043] Alkaline washing to remove silica, coal tar and organic matter adsorbed in the sedimentation tank that remain in the micropores of fine slag during the combustion process;

[0044] Rinse and repeat the above steps. The fine residue after alkali washing enters the elution device. The pH value of water washing is close to neutral and enters the next process;

[0045] Activation: steam activation is used for activation.

[0046] Screening water washing includes the following steps:

[0047] S1. Raw material preparation, first collect the fine slag to be processed, and preliminarily screen the fine slag containing larger particles in the raw material to remove these particles;

[0048] S2. Screening: Select a suitable screen or screening equipment according to the required particle size, spread the fine residue evenly on the screen, and screen it by vibration and rolling. The screened fine residue is stored separately for subsequent processing or use;

[0049] S3. Washing: prepare washing equipment, ensure sufficient water flow and appropriate washing time, put the screened fine residue into the washing tank, and use running water or spraying to wash the fine residue to remove soluble impurities and dust on the surface;

[0050] S4. Separation, dehydration and drying. After washing, the fine residue is separated from the water using a screen or a centrifuge. The washed fine residue is dehydrated to reduce the moisture content, and the dehydrated fine residue is dried.

[0051] Pickling includes the following steps:

[0052] S1. Add 4 times the mass of hydrochloric acid solution to the inside of the fine slag, with a concentration of 0.5%-1.0%;

[0053] S2. Heat the temperature to 30 degrees Celsius to 40 degrees Celsius and stir. When the pH value no longer increases and stabilizes, the pickling is completed and the pH value is in the range of 3-4.

[0054] Alkaline washing includes the following steps:

[0055] S1. Add the treated fine slag to the alkali washing tank and add 0.5%-1.0% sodium hydroxide solution twice the mass of the fine slag inside;

[0056] S2. Heat it to a temperature of 70-80 degrees Celsius, stir it for half an hour, wash it to the center with water and then dehydrate it. The iodine value of the product is between 580-620.

[0057] The steam activation method includes the following steps:

[0058] S1. Steam activation, preheating the activation furnace to the activation temperature, controlling the temperature between 700 degrees Celsius and 900 degrees Celsius, transferring the fine slag to the activation furnace, and then introducing water vapor, which reacts with the carbon on the surface of the fine slag to form a porous structure;

[0059] S2. Cooling and collection. After activation is completed, turn off the water vapor supply and allow the activated carbon to cool naturally in the activation furnace or use inert gas for cooling. The cooled activated carbon is taken out of the activation furnace for subsequent processing and storage.

[0060] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A process for producing activated carbon using gasified fine slag, characterized in that: include: Screening and washing: Since the activity of activated carbon in each particle size segment is different, it is necessary to select the fine slag with the best activity and wash away the internal sand and ash; Pickling to remove calcium oxide in the micropores. During the combustion process in the gasifier, part of the calcium carbonate is decomposed into calcium oxide and the undecomposed calcium carbonate is deposited in the micropores of the fine slag. The calcium carbonate adsorbed on the surface that is not completely washed away will affect the activity of the fine slag. After washing, the fine residue after pickling enters the 200-mesh water washing device. The pH value of the water washing is close to neutral and enters the next process; Dehydration, enter the dehydration device, wash with water until neutral and then dehydrate; Alkaline washing to remove silica, coal tar and organic matter adsorbed in the sedimentation tank that remain in the micropores of fine slag during the combustion process; Rinse and repeat the above steps. The fine residue after alkali washing enters the elution device. The pH value of water washing is close to neutral and enters the next process; Activation: steam activation is used for activation.

2. The process for producing activated carbon using gasified fine slag according to claim 1, characterized in that: The screening water washing comprises the following steps: S1. Raw material preparation, first collect the fine slag to be processed, and preliminarily screen the fine slag containing larger particles in the raw material to remove these particles; S2. Screening: Select a suitable screen or screening equipment according to the required particle size, spread the fine residue evenly on the screen, and screen it by vibration and rolling. The screened fine residue is stored separately for subsequent processing or use; S3. Washing: prepare washing equipment, ensure sufficient water flow and appropriate washing time, put the screened fine residue into the washing tank, and use running water or spraying to wash the fine residue to remove soluble impurities and dust on the surface; S4. Separation, dehydration and drying. After washing, the fine residue is separated from the water using a screen or a centrifuge. The washed fine residue is dehydrated to reduce the moisture content, and the dehydrated fine residue is dried.

3. The process for producing activated carbon using gasified fine slag according to claim 1, characterized in that: The pickling comprises the following steps: S1. Add 4 times the mass of hydrochloric acid solution to the inside of the fine slag, with a concentration of 0.5%-1.0%; S2. Heat the temperature to 30 degrees Celsius to 40 degrees Celsius and stir. When the pH value no longer increases and stabilizes, the pickling is completed and the pH value is in the range of 3-4.

4. The process for producing activated carbon using gasified fine slag according to claim 1, characterized in that: The alkali washing comprises the following steps: S1. Add the treated fine slag to the alkali washing tank and add 0.5%-1.0% sodium hydroxide solution twice the mass of the fine slag inside; S2. Heat it to a temperature of 70-80 degrees Celsius, stir it for half an hour, wash it to the center with water and then dehydrate it. The iodine value of the product is between 580-620.

5. The process for producing activated carbon using gasified fine slag according to claim 1, characterized in that: The steam activation method comprises the following steps: S1. Steam activation, preheating the activation furnace to the activation temperature, controlling the temperature between 700 degrees Celsius and 900 degrees Celsius, transferring the fine slag to the activation furnace, and then introducing water vapor, which reacts with the carbon on the surface of the fine slag to form a porous structure; S2. Cooling and collection. After activation is completed, turn off the water vapor supply and allow the activated carbon to cool naturally in the activation furnace or use inert gas for cooling. The cooled activated carbon is taken out of the activation furnace for subsequent processing and storage.

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