Because activated carbon is expensive, so is charcoal.
8200 yuan/ton
Manufacture of simple water purifier
Activated carbon has a large specific surface area and can adsorb impurities in water. After drinking water is filtered by activated carbon, harmful substances can be removed and the water quality can be improved obviously.
This activity made a simple water purifier to improve water quality.
Tools and materials
Electric drill scissors.
Plastic coke bottle, yarn rope, faucet cover, hose, gauze, rubber plug, activated carbon, ABS glue, medical stone, glass conduit, adhesive tape paper.
Activity process
1. Take a plastic coke bottle, remove the hard seat at the bottom, drill a dozen small holes in the bottom of the bottle with a red-hot drill, and plug the rubber stopper with a glass tube at the bottle mouth to make a filter screen!
2. Take another plastic coke bottle, cut off the part with the hard seat, and drill a small hole on the bottle cap as the water outlet to make a container.
3. Apply 3 cm wide ABS glue at the bottom of bottle A from 15 to 18 cm. Coat 4cm ABS glue on the inner wall at the bottom of bottle B. When the glue is slightly dry, put bottle A with a layer of gauze at the bottom into bottle B. Glue the joint of the two bottles with transparent tape paper and reinforce it with yarn rope.
4. One end of the glass conduit of bottle A is connected with a rubber tube, and the other end of the rubber tube is connected with a faucet sleeve.
5. Put 500g of activated carbon into bottle A, 10g of medical stone into bottle B, and cover the water outlet with gauze to make the simple water purifier.
Description and extension
1. Medical stone can be mineralized or not.
2. If it is necessary to detect whether the activated carbon is invalid, you can drop a few drops of HA- 1 water purifier rapid detection agent in the purified water. The test reagent is an amine compound. If the water turns pale yellow after dripping, it means that the activated carbon has failed and should be replaced.
Activated carbon activated carbon
It is a black powder, granular or pellet amorphous carbon, the main component is carbon, but also contains a small amount of oxygen, hydrogen, sulfur, nitrogen and chlorine. It also has a fine structure similar to graphite, but the grains are small and irregularly stacked between layers. It has a large specific surface area (500 ~ 1000m2/g) and strong adsorption performance, and can adsorb gas, liquid or colloidal solid on its surface. For gases and liquids, the quality of adsorbed substances can be close to that of activated carbon itself. Its adsorption is selective, and nonpolar substances are easier to adsorb than polar substances. In the same series of substances, the higher the boiling point, the easier it is to be adsorbed. The greater the pressure, the lower the temperature, the greater the concentration and the greater the adsorption capacity. On the contrary, decompression and heating are beneficial to gas desorption. It is often used in gas adsorption, separation and purification, solvent recovery, decoloring agent for sugar solution, grease, glycerin and medicine, deodorizer for drinking water and refrigerator, filter agent in gas mask, catalyst or carrier of metal salt catalyst. The raw materials for the early production of activated carbon were wood, hard shells or animal bones, and later coal was mainly used. After dry distillation activation, the production method of activated carbon is as follows: ① activation of steam and gas. Carbon is activated by steam or carbon dioxide at 850 ~ 900℃. ② Chemical activation method. Activated carbon can be obtained by using the gas released by activator or impregnating raw materials with activator after high temperature treatment.
Activated carbon has a microcrystalline structure, and the arrangement of microcrystals is completely irregular. There are micropores (radius less than 20[ angstrom] =10-10m), transition holes (radius 20- 1000) and macropores (radius1000-0/00000) in the crystal. This determines that activated carbon has good adsorbability, which can adsorb metal ions, harmful gases, organic pollutants, pigments and so on in wastewater and waste gas. The application of activated carbon in industry also requires high mechanical strength and good wear resistance. Its structure is stable, and the energy required for adsorption is small, which is beneficial to regeneration. Activated carbon is used for decolorization and deodorization of oil, beverage, food and drinking water, gas separation, solvent recovery and air conditioning, as a catalyst carrier and an adsorbent for gas masks.
Physical characteristics:
Activated carbon is a porous carbonized material with extremely rich pore structure and good adsorption characteristics. Its adsorption is formed by physical and chemical adsorption forces, and its appearance is black. In addition to the main carbon, it also contains a small amount of hydrogen, nitrogen and oxygen, and its structure looks like a hexagon. Because of the irregular hexagonal structure, it has the characteristics of many bodies and high surface area. The specific surface area per gram of activated carbon is equivalent to 1000 square meter.
Activated carbon material:
Activated carbon is mainly made of substances with high carbon content, such as wood, coal, shells, bones and petroleum residues. Coconut shell is the most commonly used raw material. Under the same conditions, coconut shell has the best active quality and other special characteristics because of its largest specific surface area.
Cost of activated carbon:
If the cost of activated carbon is calculated by raw materials, the most expensive is coconut shell, followed by wood and coal quality. However, there are many levels of deep processing of activated carbon, and different deep processing of the same product will also cause huge differences in costs. Customers should mainly choose the corresponding activated carbon products according to their actual applications.
Production process:
According to the production method, activated carbon can be produced by physical steam method and chemical method. This paper focuses on the physical steam production. Generally speaking, production is divided into two processes. The first step is carbonization. The raw materials were dried at the temperature of 170 ~ 600, and 80% of R organic tissues were carbonized in the same amount. Step 2, activation: the carbonized material in step 1 is sent into a reaction furnace to react with an activating agent and water vapor to complete the activation process and make a finished product. During the endothermic reaction, the combined gas of CO and H2 is mainly produced, which is used to heat the carbonized material to a suitable temperature (800- 1000℃) and remove all its decomposable substances, resulting in rich pore structure and huge specific surface area, which makes the activated carbon have strong adsorption force. The pore size of activated carbon produced by different raw materials is different, among which the pore size of activated carbon made of coconut shell is the smallest, the pore size of wood activated carbon is generally larger, and the pore size of coal activated carbon is between the two. The pore size of activated carbon is generally divided into three categories: macropore:1000-1000-1000000a transition pore: 20- 1000A micropore: 20A According to the above characteristics, it can be seen that the corresponding activated carbon should be selected for different adsorption objects to achieve the best cost performance. Therefore, generally speaking, in liquid phase adsorption, more transition pore sizes and larger average pore sizes should be selected.
Regeneration of activated carbon
After the adsorption capacity of granular activated carbon is exhausted, the common method is heating, and the waste carbon is roasted in a regeneration furnace at about 850℃. The loss of granular activated carbon per regeneration is about 5 ~ 10%, and the adsorption capacity gradually decreases. The regeneration efficiency has a great influence on the operating cost of activated carbon filter (that is, the water treatment cost).
Activated carbon application:
According to the adsorption characteristics of activated carbon, activated carbon is mainly used to remove pollutants in water, decolorize, filter and purify liquids and gases. It is also used for air purification, waste gas recovery (such as the recovery of gas "benzene" in chemical industry) and the recovery and refining of precious metals (such as the absorption of gold). With the development of science, the use of activated carbon is more and more extensive, and with the country's attention to the ecological environment, activated carbon has also played an increasingly important role.
medical science
Alias activated carbon and medicinal charcoal are suitable for diarrhea, flatulence and food poisoning. Dosage and usage: Oral: 65438+ 0.5 ~ 4g each time, 2 ~ 3 times a day, before meals. After taking this product, you can also take magnesium sulfate to expel toxic substances. Precautions can adsorb vitamins, antibiotics, sulfonamides, alkaloids, lactobacillus, hormones, etc. It will also affect the activities of protease and pancreatin, which is not suitable for combination. Specification tablets: 0. 15g, 0.3g, 0.5g per tablet.
Patented technology of activated carbon production
1, 2.4 mm coal-supported activated carbon and its use
2. Preparation method of special activated carbon for platinum group metal catalyst carrier
3. Preparation and technology of pyrolytic activated carbon from herbs and crops.
4. Long-acting broad-spectrum bactericidal activated carbon
5. Normal temperature modified activated carbon organic sulfur desulfurizer and its preparation method
6. Ultra-low ash and high adsorption value granular activated carbon and its manufacturing method
7. Preparation of activated carbon with ultra-high specific surface area
8. Method of producing activated carbon by using municipal waste and carbonizer.
9. Special activated carbon for removing bitterness and peculiar smell in wine.
10, method for preparing activated carbon from municipal waste
1 1 preparation method of macroporous mesoporous high-performance activated carbon
12, co-production of sodium silicate and activated carbon from rice husk ash
13, powdered activated carbon regeneration technology and device
14, composite carrier activated carbon rod and preparation method thereof
15. Preparation method of pitch-based spherical activated carbon rich in mesopores
16, preparation method of activated carbon with high specific surface area
17, activated carbon with high specific surface area and its preparation method
18, Manufacturing Technology of High Stack Weight Activated Carbon
19, high wear-resistant activated carbon and its preparation method
20. A preparation method of granular activated carbon with high decolorization performance.
2 1, preparation method of activated carbon with high adsorption performance
22. A method for manufacturing high-performance activated carbon from stone shells.
23, synthetic ammonia by-product carbon black granular activated carbon preparation method
24, chemical catalytic method to produce high quality activated carbon
25, chemical production of wood amorphous granular activated carbon technology
26, chemical method to manufacture activated carbon liquid carbonization technology.
27. Production of activated carbon by zinc chloride weighing method.
28. Activated carbon regeneration method and equipment Activated carbon for nitrobenzene wastewater treatment process.
29, activated carbon activation method and equipment
30, activated carbon regeneration method
3 1, activated carbon regeneration method 2
32, the manufacturing method of activated carbon
33. Production method of activated carbon 2
34. Activated carbon and its manufacturing method
35. Activated carbon defluorinating agent and its manufacturing method
36, activated carbon desulfurizer and preparation
37, activated carbon forced discharge regeneration technology and its device
38, activated carbon commercialization post-treatment method
39, activated carbon production method
40. Composite activator for activated carbon production
4 1, preparation method of activated carbon
42, activated carbon manufacturing equipment and methods
43. A preparation method of sisal stalk-based activated carbon
44, furfural residue activated carbon and its application in the removal and recovery of sulfur dioxide in flue gas.
45. High activated carbon prepared by causticizing rice husk ash and its preparation method.
46, garbage separation and classification method of producing activated carbon
47, garbage incinerator coupling activation furnace preparation method of high surface activated carbon.
48. Method for preparing activated carbon by pyrolyzing and regenerating carbon powder from waste tires
49, using by-product carbon black to produce desulfurization and denitrification activated carbon.
50. Use straw and sawdust to make activated carbon for vehicles.
5 1. Method of making activated carbon from distiller's grains
52. A method for preparing activated carbon from carbon black.
53. A method for preparing activated carbon from a novel carbonaceous material.
54. A preparation method of pitch-based spherical activated carbon
55, continuous hot extrusion casting activated carbon column preparation method
56, grain medicine activated carbon
57, phosphoric acid method to produce activated carbon method and equipment.
58, coal fluidized bed carrier activated carbon and its manufacturing method
59, coal vacuum carrier activated carbon manufacturing technology
60, coal activated carbon forming agent
6 1, regeneration method of powdered activated carbon for enzymatic starch sugar production
62. Preparation of activated carbon from lignite
63, indirect heating activated carbon regeneration device and regeneration method
64, indirect heating activated carbon regeneration device and regeneration method 2
65, brick kiln mixed burning granular activated carbon method
66. columnar activated carbon production method of weakly caking coal.
67. Petroleum pitch-based activated carbon and its preparation method.
68. A method for preparing high-performance activated carbon from edible rice.
69, carbonization furnace direct production of activated carbon method
70. Method for preparing pitch-based spherical activated carbon by adding metal inorganic salts.
7 1, activated carbon fine desulfurizer for removing mercaptan and sulfide and preparation method thereof
72, preparation method of desulfurization activated carbon
73, desulfurization and denitrification activated carbon and its production method
74, microwave radiation method to manufacture powdered activated carbon.
75, microwave radiation method from tobacco stem solid waste to make activated carbon.
76, microwave regeneration method of volatile nonpolar organic activated carbon.
77. Microspherical activated carbon and its preparation method
78, Chinese tallow seed shell granular activated carbon and its preparation method
79, dust-free activated carbon processing method
80. Pentaphyllum activated carbon
8 1. Preparation method of activated carbon for adsorbing and storing methane
82, pressure dissolved activated carbon biological regeneration method
83. A shaped activated carbon and a manufacturing method thereof.
84. A preparation method of coal-based activated carbon with low acid-soluble ash and acid-soluble iron value.
85. A preparation method of phenolic resin-based spherical activated carbon
86. An activated carbon with high specific surface area.
87. A dry desulfurizer impregnated with high-sulfur activated carbon.
88. A preparation method of activated carbon with high density and high specific surface area.
89. A preparation method of high-strength resin-based spherical activated carbon
90. A method for industrial production of activated carbon.
9 1, a production process of activated carbon
92. A surface modification method of activated carbon fiber.
93. Regeneration method of activated carbon fiber.
94. A preparation method of activated carbon fiber with high desulfurization rate.
95. A method for controlling pore size distribution of phenolic activated carbon fiber.
96. A method for controlling the pore structure of activated carbon.
97. A method for producing activated carbon from white carbon black waste residue.
98. A method for producing coal-based mesoporous activated carbon.
99. A method for producing activated carbon for solvent recovery of wood particles.
100, a preparation method of spherical activated carbon
10 1. Preparation method of resin-based spherical activated carbon
102, a method for preparing spherical activated carbon by adding pore-forming agent.
103 chromium-free impregnated activated carbon and its preparation method
104. A method for preparing activated carbon from terephthalic acid oxidation residue
105, preparation of amorphous granular activated carbon from anthracite and its manufacturing method.
106. Preparation method of activated carbon for storing methane
107, a method for producing activated carbon from boiler ash
108, regeneration method of gold-loaded activated carbon
109, preparation method of silver-loaded activated carbon
1 10, a method for preparing activated carbon.
1 1 1, a method for preparing activated carbon 2.
1 12, preparation method of mesoporous phenolic resin-based spherical activated carbon
1 13, preparation method of mesoporous pitch-based spherical activated carbon
1 14, a production process of bamboo activated carbon.
1 15. The technology of making beverage, oil and activated carbon from hawthorn kernel.
1 16, Method of making water glass from rice husk ash carbon and by-product activated carbon
1 17. Method for manufacturing activated carbon from neem shell
1 18, making activated carbon from petroleum coke
1 19. Method for preparing activated carbon from citric acid waste residue by dry fermentation of potatoes.
120, method for manufacturing activated carbon from coal water slurry
12 1, making activated carbon with additives.
122, method of making activated carbon from coconut residue
123. Method for preparing activated carbon with ultra-high specific surface area from asphalt
124, preparation of silica gel-activated carbon composite adsorbent from coal gangue
125, method for manufacturing granular activated carbon from coal
126. Method for preparing activated carbon with high specific surface area from petroleum coke
127, method for preparing activated carbon from bamboo raw materials
128, producing granular activated carbon from corncob furfural residue
129, comprehensive treatment method of making activated carbon from papermaking wastewater
130, preparation method of viscose fiber activated carbon
13 1. Activated carbon honeycomb made directly from carbon
132, method of producing activated carbon by vertical furnace
133, method for preparing activated carbon
134, a new process for preparing amorphous silica and activated carbon.
135, preparation method of activated carbon for manufacturing supercapacitor electrodes.
136, preparation method of activated carbon with developed mesopores
137, coal-based granular activated carbon with developed mesopores and micropores and its production method
3 Attribute: Adsorption
Adsorption performance is the main performance of activated carbon. Activated carbon has microcrystals similar to graphite particles, but the arrangement is irregular. During the activation process, pores with different shapes and sizes will be generated between microcrystals. Assuming that the pores of activated carbon are cylindrical, the radius of pores can be divided into two categories according to certain methods:
(1) According to IUPAC:
micropore
Mesoporous 1-25 nm
Macropore > 25 nm.
(2) According to the habit:
micropore
Mesoporous 150-20000 nm
Macropore > 20000 nm.
Because these pores, especially micropores, provide a huge surface area.
Generally, the pore volume of micropores is only 0.25-0.9mL/g, the number of pores is about 1.020 /g, and the surface area of all micropores is about 500- 1.500 m2/g, which is usually measured by the BET method, and it is also called as high as 3,500-5,000m2/g. Activated carbon is almost 95%. The pore volume of mesopores is generally about 0.02- 1.0mL/g, and the maximum surface area can reach several hundred square meters, which is generally only about 5% of the total silkworm eggs of activated carbon. Its function can adsorb steam, provide a channel for adsorbate to enter micropores, and directly adsorb larger molecules.
The pore volume of macropores is generally about 0.2-0.5 mL/g, and the surface area is only about 0.5-2 m2/g. Its function is to make adsorbate molecules quickly penetrate into smaller pores in activated carbon. Secondly, when used as a catalyst carrier, a small amount of catalyst is often precipitated from micropores, mostly in macropores and mesopores.
The surface area of activated carbon should include internal surface area and external surface area. In fact, the adsorption performance mainly comes from the huge internal surface area, and it should not be mistaken that grinding activated carbon will obviously increase the surface area and thus improve the adsorption force.
Many adsorbents are reversible physical adsorption, that is, adsorbate is a fluid, which is adsorbed by activated carbon at a certain temperature and pressure, desorbed at high temperature and low pressure, and the inner surface of activated carbon returns to its original state. This is a widely used physical adsorption, also known as van der Waals adsorption academically.
chemical property
Adsorption of activated carbon includes physical adsorption and chemical adsorption. Adsorption of activated carbon depends on pore structure and chemical composition.
Activated carbon contains not only carbon, but also a small amount of oxygen and hydrogen, which are chemically combined and begin to be functionalized, such as carbonyl, carboxyl, phenols, lactones, quinones and ethers. Some of the oxides and complexes contained on these surfaces are derived from the derivatives of raw materials, and some are generated by the action of air or water vapor during or after activation. Sometimes surface sulfides and chlorides are produced. In the process of activation, minerals contained in raw materials are concentrated into ash in activated carbon, and the main components of ash are salts of alkali metals and alkaline earth metals, such as carbonate and phosphate.
These ash contents can be reduced by washing or pickling.
Inorganic components in activated carbon can be seen from the analysis of four powdered carbon products in Table 3- 1. (table omitted)
catalysis
Activated carbon is accompanied by catalysis in many adsorption processes, showing the activity of catalyst. For example, sulfur dioxide adsorbed by activated carbon is converted into sulfur trioxide by catalytic oxidation.
Due to the existence of oxygen-containing compounds or complexes on specific surfaces, activated carbon has catalytic activity for many reactions, such as making chlorine and carbon monoxide produce phosgene.
Due to the formation of complex between activated carbon and carrier, the catalytic activity of this complex catalyst is greatly improved. For example, palladium salt supported on activated carbon can catalyze the oxidation of olefins even without the catalyst of copper salt, and it is fast and selective.
Activated carbon can be used as catalyst carrier because of its developed fine pore structure, huge internal surface area and good heat resistance, acid resistance and alkali resistance. For example, activated carbon is an excellent carrier for platinum and palladium catalysts in hydrogenation, dehydrocyclization and isomerization reactions in organic chemistry.
mechanicalness
Download several items to show the mechanical properties of activated carbon, which is valued by users of activated carbon, especially a large number of industrial users.
(1) particle size: using a set of standard screen screening methods, the weight of activated carbon left in and passing through each screen is calculated, indicating the particle size distribution.
(2) Static density or bulk density: the weight of activated carbon in unit volume of dietary pore volume and interparticle pore volume.
(3) Volume density and particle density: the weight of unit volume of activated carbon that eats pore volume but does not eat interstitial volume between particles.
(4) Strength: namely, the crushing resistance of activated carbon.
(5) Wear resistance: that is, wear resistance or abrasion resistance.
These mechanical properties directly affect the application, such as: density affects the size of the container; The thickness of toner affects filtration; The particle size distribution of granular carbon affects the fluid resistance and pressure drop; Fragmentation affects the service life and regeneration of waste carbon.
4 manufacturing industry
4. 1 raw materials
Almost all carbon-containing materials can be used to tax activated carbon, such as wood, sawdust, peat, straw and other cellulose materials usually only undergo chemical activation treatment. There are friction tests made of rice straw and corn straw, and activated carbon made of activated bean dregs by potassium carbonate.
Although the raw materials are usually carbonized first in the gas activation method, it is reported that foreign companies use peat for direct gas activation instead of friction carbonization.
The raw materials suitable for gas activation method are charcoal, nut shell charcoal, lignite or coke made of peat.
4.2 activation
The key process of making activated carbon is activation. Due to the different activators used, it can be divided into two methods:
(1) chemical activation method with chemical substances such as zinc chloride or phosphoric acid as activator;
(2) A gas activation method using steam or carbon dioxide as an activator.
The former is called chemical activation method and the latter is called physical activation method. In fact, the two activation processes are both changes in people's livelihood and chemical changes.
Chemical activation method
(1) zinc chloride activation method
Chemical zinc chloride is used as an activator.
0.4-0.5 part of zinc chloride concentrated solution and/kloc-0 part of peat or sawdust are mixed, dried in a converter, heated to 600-700 DEG C, washed with acid and water, and zinc salt is recovered. Sometimes after chemical activation, steam activation is continued to increase pores, and China keeps our friendship.
Activated carbon activated by zinc chloride has many advantages. Although this is an effective and simple method, it is gradually declining due to the pollution of zinc compounds to the environment.
(2) Phosphoric acid activation method
Chemical phosphoric acid is used as an activator.
Carbonized or non-carbonized carbonaceous materials are used as raw materials. For example, fine sawdust and phosphoric acid are mixed into slurry, dried in a converter and heated to 400-600℃. Recovery of phosphoric acid by extraction, sometimes after neutralization. Activated carbon obtained by drying usually has finer pores than activated carbon obtained by zinc chloride method.
A combined activation method of phosphoric acid and steam can also be used. In recent years, phosphoric acid activation method tends to be widely used, and innovations such as phosphoric acid recovery have not been disclosed.
(3) Potassium hydroxide activation method
Chemical potassium hydroxide is used as an activator.
Carbon-containing raw materials are treated with molten anhydrous potassium hydroxide, and the fierce reaction produces high porosity, and the specific surface area can be as high as 3000 m2/g. ..
(4) activation method of other chemicals
Sulfuric acid, potassium sulfide, aluminum chloride, ammonium chloride, borate, boric acid, calcium chloride, calcium hydroxide, chlorine, hydrogen chloride, iron salt, nickel salt, nitric acid, nitrogen, phosphorus trioxide, metal potassium, potassium permanganate, metal sodium, sodium oxide and sulfur dioxide can all be used for activation.
4.2.2 Gas activation method
Using steam, carbon dioxide or their mixed gases as activators, carbon-containing substances and gases are oxidized in a converter or a boiling furnace at a high temperature of 800- 1000℃ to prepare activated carbon with developed pore structure.
The reaction of steam, carbon dioxide and carbon is endothermic, while the reaction of oxygen and carbon is very exothermic, so it is difficult to control the reaction temperature in the furnace, especially to avoid local overheating and uneven activation, so neither oxygen nor air is suitable as an activator. Sometimes a mixture of air and water vapor is used, and the combustion of carbon is used as a heat source. In most cases, a small amount of chlorine will inevitably be mixed into the mixed gas of flue gas and steam, resulting in the simultaneous activation of steam, carbon dioxide and oxygen.
It is worth noting that a small amount of oxygen in the mixed gas will make the activated carbon produce larger pores. The reaction speed of oxygen and carbon is 100 times faster than that of carbon dioxide, and it is greatly improved because of the existence of potassium salt. Therefore, the potassium-containing raw materials will react violently in the oxygen-containing gas, resulting in out-of-control combustion rather than activation.
A few compounds, such as alkali metal salts and alkaline earth metal salts, almost all chlorides, sulfates, acetates and carbonates, as well as most acids and hydroxides, have catalytic acceleration in gas activation. The commonly used catalysts in industry are potassium hydroxide and potassium carbonate, and the dosage is between 0. 1%-5%. Solid catalyst and carbonaceous material are mixed, or added into solution, or molded and carbonized at low temperature.
If bituminous coal is activated by adding alkali metal salts, it should be activated not only by steam, but also by mixed gas containing carbon dioxide.
4.3 Activation furnaces: There are many kinds of activation furnaces. The main furnace types used in activated carbon production plants abroad are shaft furnace, converter and fluidized bed furnace.
(1) shaft furnace: It was originally composed of several simple vertical combustion chambers, and the furnace wall was built with refractory bricks. Later, the mixing was improved, and the direction, speed and temperature of airflow in the furnace were managed. The furnace can also be used to regenerate and recover carbon.
(2) Converter: It is the most common horizontal activation furnace.
(3) Fluidized bed furnace: also known as fluidized bed furnace, it is a suspended state blown by solid particles as supplementary fluid. The heat and mass transfer rate between gas and solid is fast, but the particle wear is large. In the past, powdered carbon was often produced by batch method, but now it has been developed into continuous production and can be made into grinding granular carbon.
At present, the commonly used activation furnaces in China mainly include:
(1) Sliding furnace: Also known as saddle furnace, it was first patented in France because of the saddle-shaped refractory bricks in its activation zone, and was introduced to China by the former Soviet Union in 1950s. After a series of improvements, it has become the most important furnace type for producing granular activated carbon in China.
Activated gas: water vapor.
Main advantages: continuous production, large output, high quality, high superheated steam temperature, stability and no need for external heating.
Main problems: high requirements for raw materials, high cost, high technical requirements and high maintenance costs.
(2) stewing furnace:
Activated gas: high temperature flue gas produced by coal burning.
Main advantages: simple investment.
Main problems: high oil consumption, uneven activation, high labor intensity and large dust.
(3) earth raking furnace:
Activation gas: water vapor (air)
Main advantages: the furnace type is the simplest.
Main problems: low output, poor quality, primitive workshop style and environmental pollution.
(4) Multi-tube furnace:
Activated gas: water vapor
Main advantages: no fuel, stability, easy control and large output.
Main problems: uneven activation, low carbon content, low superheated steam temperature, easy damage of refractory pipes and large investment.
(5) Rotary furnace:
Activated gas: flue gas, water vapor.
Main advantages: continuous operation and uniform activation, suitable for producing gas-phase activated carbon.
Main problems: huge equipment, poor thermal efficiency, high oil consumption and low quality of finished products.
(6) Boiling furnace
Activated gas: air, water vapor.
Main advantages: good gas-solid contact, uniform activation and small mechanized floor space.
Main problems: intermittent production, easy slagging and affecting normal operation and fuel consumption.
(7) Multi-layer rake furnace
Activated gas: flue gas, water vapor.
Main advantages: imported large-scale equipment, high activation strength and large output. Adapt to a variety of products.
Main problems: large investment, high technical requirements and high operating costs.
In addition, there are multi-tube boiling furnaces, overflow boiling furnaces, swirl spouting activation furnaces, tunnel kiln activation furnaces and inclined plate activation furnaces.
4.4 Post-treatment
Impurity removal: Activated carbon with catalysts such as zinc chloride, phosphoric acid and potassium carbonate is usually treated with acid washing or water washing to reduce the content of various compounds.
Low ash activated carbon can be washed with water, hydrochloric acid or nitric acid to remove some impurities. Activated carbon used for fine chemicals, drugs, catalysts and catalyst carriers needs special and sufficient washing.
Impregnation: Impregnation of activated carbon is a post-treatment for a specific purpose.
(1) Impregnate activated carbon with copper salt and chromium salt to protect toxic gas.
(2) Activated carbon used for denitrification is impregnated with zinc salt.
(3) Treating activated carbon for removing hydrogen sulfide from oxygen-containing gas and mercury vapor from waste gas with iodine compound.
(4) Activated carbon used to extract radioactive methyl iodide and other gases from nuclear devices is also treated with iodine compounds.
(5) Activated carbon used for oxidizing hydrogen sulfide and formaldehyde into nontoxic substances is impregnated with manganese dioxide. At high temperature, formaldehyde will not be oxidized to formic acid, but will directly generate carbon dioxide.
(6) Impregnating the activated carbon for removing divalent compounds from the gas mixture with low oxygen content with iron salt, and then heating and converting it into trivalent iron oxide.
(7) Activated carbon used to eliminate mercury vapor from natural gas, hydrogen and other gases is treated with elemental sulfur.
(8) Activated carbon used for drinking water purification is impregnated with silver salt.
(9) Activated carbon of catalysts used for various purposes is impregnated with noble metal compounds. For example, activated carbon coated with palladium is a typical hydrogenation catalyst.
(10) Activated carbon used to oxidize mercaptan in mineral oil was impregnated with cobalt phthalocyanine.