Activated carbon with high sulfur resistance and high denitration rate and preparation method thereof
阅读说明：本技术 一种高抗硫性高脱硝率的活性炭及其制备方法 (Activated carbon with high sulfur resistance and high denitration rate and preparation method thereof ) 是由 李小龙 魏进超 杨本涛 康建刚 李俊杰 于 2020-05-11 设计创作，主要内容包括：一种高抗硫性高脱硝率活性炭的制备方法,该方法包括以下步骤：1)将原料煤、沥青、金属矿混合,然后任选地加入粘结剂、水,进行混合,混合均匀后得到混合原料；将混合原料挤压成型,得到活性炭前驱体成型料；将活性炭前驱体成型料进行干燥,得到干燥料；2)将干燥料加入到炭化炉中进行炭化,得到炭化料；3)将炭化料加入到活化炉中进行活化,得到高抗硫性高脱硝率活性炭。本发明在原料中直接加入金属矿石,通过采用强力混合工艺和控制炭化活化反应条件来调控活性炭内金属氧化物的形态,制备得到负载均匀金属氧化物和高比表面积的活性炭,具有流程短、投资低的优点。(A preparation method of activated carbon with high sulfur resistance and high denitration rate comprises the following steps: 1) mixing raw material coal, asphalt and metal ore, then optionally adding a binder and water, mixing, and uniformly mixing to obtain a mixed raw material; extruding and molding the mixed raw materials to obtain an active carbon precursor molding material; drying the active carbon precursor molding material to obtain a dried material; 2) adding the dried material into a carbonization furnace for carbonization to obtain a carbonized material; 3) and adding the carbonized material into an activation furnace for activation to obtain the activated carbon with high sulfur resistance and high denitration rate. According to the invention, metal ore is directly added into the raw materials, the form of the metal oxide in the activated carbon is regulated and controlled by adopting a strong mixing process and controlling the carbonization and activation reaction conditions, and the activated carbon loaded with uniform metal oxide and high specific surface area is prepared, and the method has the advantages of short process and low investment.)
1. A preparation method of activated carbon with high sulfur resistance and high denitration rate comprises the following steps:
1) mixing raw material coal, asphalt and metal ore, then optionally adding a binder and water, mixing, and uniformly mixing to obtain a mixed raw material;
1a) extruding and molding the mixed raw materials to obtain an active carbon precursor molding material;
1b) drying the active carbon precursor molding material to obtain a dried material;
2) adding the dried material into a carbonization furnace for carbonization to obtain a carbonized material;
3) and adding the carbonized material into an activation furnace for activation to obtain the activated carbon with high sulfur resistance and high denitration rate.
2. A preparation method of activated carbon with high sulfur resistance and high denitration rate comprises the following steps:
1) mixing raw material coal, asphalt and metal ore, then optionally adding a binder and water, mixing, and uniformly mixing to obtain a mixed raw material;
1a) extruding and molding the mixed raw materials to obtain an active carbon precursor molding material;
1b) drying the active carbon precursor molding material to obtain a dried material;
2) adding the dried material into a carbonization furnace for carbonization to obtain a carbonized material;
3) adding the carbonized material into an activation furnace for activation to obtain an activated material;
4) and (3) grinding the activated material to obtain the powdered activated carbon with high sulfur resistance and high denitration rate.
3. The method of claim 1, wherein: the method further comprises the following steps:
4) cooling and screening the activated high-sulfur-resistance high-denitration-rate activated carbon to obtain large-particle high-sulfur-resistance high-denitration-rate activated carbon;
5) and (3) returning the small-particle activated carbon obtained after cooling and screening to the step 1) for reuse or grinding into powder activated carbon.
4. The production method according to any one of claims 1 to 3, characterized in that: the metal ore in the step 1) is iron-containing ore; preferably one or more of iron manganese ore, iron copper ore, iron titanium ore and iron tungsten ore; the binder is one or more of coal tar, carboxymethyl cellulose, polyvinyl alcohol and sesbania powder;
preferably, the ratio of the addition amount of the metal ore in the step 1) to the addition amount of the raw material coal is a; wherein: 0 < a.ltoreq.15%, preferably 0.1% < a.ltoreq.10%, more preferably 0.5% < a.ltoreq.8%.
5. The production method according to any one of claims 1 to 4, characterized in that: in the step 2), the concentration of CO in the carbonization furnace is controlled in the carbonization process; preferably, the concentration of CO in the carbonization furnace is controlled to be b by regulating the addition amount of fuel (such as coal powder or coal gas) at the source of a heat source of the carbonization furnace, wherein: b is more than 0 and less than or equal to 45 percent, preferably more than 0.1 percent and less than or equal to 40 percent, and more preferably more than 0.5 percent and less than or equal to 37 percent; and/or
In the step 2), controlling the concentration of oxygen in the carbonization furnace in the carbonization process; preferably, the oxygen concentration in the carbonization furnace is controlled to be c by regulating the supplement amount of oxygen-containing gas (such as air) in the carbonization furnace, wherein: 0 < c.ltoreq.17%, preferably 0.1% < c.ltoreq.15%, more preferably 0.5% < c.ltoreq.12%.
6. The production method according to any one of claims 1 to 5, characterized in that: introducing mixed gas of water vapor and oxygen into the activation furnace in the activation reaction process in the step 3); preferably, the volume fraction of the oxygen amount in the mixed gas to the water vapor amount is 0.1 to 5%, preferably 0.3 to 4%, and more preferably 0.5 to 3%.
7. The production method according to any one of claims 1 to 6, characterized in that: the step 1) is specifically as follows: respectively grinding raw material coal, asphalt and metal ore into powder, mixing, optionally adding a binder and water, mixing, and uniformly mixing to obtain a mixed raw material; preferably, the milling is to mill the raw material coal, the asphalt and the metal ore respectively until more than 90% of the raw material coal, the asphalt and the metal ore pass through 200 meshes, preferably more than 95% of the raw material coal, the asphalt and the metal ore pass through 200 meshes, and more preferably more than 97% of the raw material coal, the asphalt and the metal ore pass through 200 meshes; or
The milling is to mill the raw material coal, the asphalt and the metal ore respectively until more than 70% of the raw material coal, the asphalt and the metal ore pass through 325 meshes, preferably more than 75% of the raw material coal, the asphalt and the metal ore pass through 325 meshes, and more preferably more than 80% of the raw material coal, the asphalt and the metal ore pass through 325 meshes.
8. The production method according to any one of claims 1 to 7, characterized in that: the temperature range of carbonization in the step 2) is 300-1000 ℃, preferably 400-950 ℃, and more preferably 500-900 ℃; the carbonization time in the step 2) is 15-180 min, preferably 20-120 min, and more preferably 30-90 min; and/or
The temperature range of the activation reaction in the step 3) is 700-1100 ℃, preferably 800-1000 ℃, and more preferably 850-950 ℃; the time of the activation reaction in the step 3) is 20-240 min, preferably 30-180 min, and more preferably 40-120 min.
9. The production method according to any one of claims 1 to 8, characterized in that: the mixing in the step 1) adopts an intensive mixer to carry out intensive mixing; preferably, the intensive mixer is a vertical intensive mixer or a horizontal intensive mixer;
preferably, the degree of mixing of the mixed raw materials in step 1) is 75% or more, preferably 80% or more, and more preferably 85% or more.
10. The production method according to any one of claims 1 to 9, characterized in that: the shape of the active carbon precursor molding material in the step 1a) is one or more of spherical, cylindrical and rectangular; preferably, the shape of the active carbon precursor molding material is cylindrical, and the size of the cylindrical active carbon precursor molding material is 4-12 mm, preferably 4.5-11 mm, and more preferably 5-10 mm; and/or
In step 1b), the active carbon precursor molding material is dried until the water content is less than 13%, preferably less than 10%, and more preferably less than 8%.
11. The utility model provides a high denitrating rate active carbon of high sulfur resistance which characterized in that: the activated carbon with high sulfur resistance and high denitration rate is prepared by the method of any one of claims 1 to 10.
Technical Field
The invention relates to a preparation method of activated carbon for flue gas desulfurization and denitration, in particular to activated carbon with high sulfur resistance and high denitration rate and a preparation method thereof, and belongs to the technical field of activated carbon preparation.
Background
NOxIs one of the main pollution pollutants of the atmosphere, can cause acid rain, photochemical pollution and damage the ozone layer, and seriously threatens the production and the life of human beings. Nearly 37% of NO in atmosphere in ChinaxThe emission from fixed sources such as thermal power generation and boiler combustion, and the development of industrial furnaces and kilns NOxEmissions control technology research is particularly important.
Sintering flue gas in the steel industry is a main source for emission of atmospheric pollutants, and mainly comprises various pollutants such as sulfur dioxide, nitric oxide, particulate matters, dioxin, heavy metals (lead, arsenic, good fortune, chromium, mercury and the like), fluoride and volatile organic compounds ((VOCs)xThe removal process mainly comprises an SCR process and an active carbon method process, and NH is used3Selective catalytic reduction of NO for a reductantxHas been widely studied and applied, conventional V2O5-WO3/TiO2The catalyst has high NO at 300-400 DEG CxPurification efficiency and SO resistance2The poisoning capacity, but the catalytic activity at lower temperatures is lower, and in order to meet the activity and sulfur resistance requirements, the SCR device usually needs to be preheated or modified again to raise the temperature of the flue gas, thereby increasing the energy consumption and increasing the operating cost. Because the activated carbon flue gas purification technology can not only remove NO in the flue gasxAnd can realize SO in the sintering flue gas2Dust, dioxin and other toxic substances are removed in an integrated and combined manner, and finally, the deep treatment of the flue gas and the resource utilization of waste are realized, so that the method gradually becomes the optimal scheme for atmospheric treatmentAnd techniques. But NO of activated carbon process compared to SCR processxThe purification efficiency is low, and if the denitration reaction efficiency of the activated carbon can be effectively improved, the integrated high-desulfurization and high-denitration effect of the activated carbon can be realized, so that the problem of urgent breakthrough is solved by improving the denitration rate of the activated carbon in the activated carbon method.
In order to further improve the denitration performance of the activated carbon, a series of researches are carried out on raw material selection and process flows by many scientific researchers, but the application of the activated carbon is still limited. At present, the preparation method for improving the denitration efficiency of activated carbon mainly adopts an impregnation method, for example, Chinese patent CN 104190432B, a low-temperature denitration and desulfurization activated carbon catalyst and a preparation method thereof, mixes prepared activated carbon with a transparent solution decorated by ammonium metavanadate, ferric nitrate and nitric acid, and supports the catalyst on the activated carbon through impregnation. The method has the defects of complex preparation process, long impregnation time and low impregnation rate. In order to shorten the process flow, part of patents report that in the original activated carbon preparation mixing step, a certain amount of metal salt solution is added to be mixed with the raw materials, and then the activated carbon with high denitration rate is obtained by combining other preparation steps. For example, Chinese patent CN 106672967B, preparation method of activated carbon for desulfurization and denitrification, activated carbon for desulfurization and denitrification and application thereof, and CN 110368927A, preparation method of manganese oxide/activated carbon denitration catalyst. That is, the existing principle for improving the denitration rate of activated carbon is mainly to make the activated carbon load catalytic active metal, and the used method is to convert the metal into a solution and compound the metal with the activated carbon by adding or soaking in the form of auxiliary materials. However, since metals are generally difficult to dissolve, the method also has the defects of complex preparation process of metal salt solution, limited metal addition types and the like.
Disclosure of Invention
Aiming at the defects in the prior art, the invention aims to provide the activated carbon with high sulfur resistance and high denitration rate and the preparation method thereof. According to the method, metal ore is directly added into the preparation raw materials, the form of the metal oxide is regulated and controlled by adopting a strong mixing process and simultaneously controlling the carbonization and activation reaction conditions, the uniform distribution and the activation of the metal oxide in the activated carbon are realized, the specific surface area of the activated carbon is increased, and finally the uniformly loaded metal oxide and the activated carbon with high specific surface area are obtained.
According to a first embodiment of the present invention, there is provided a method for producing activated carbon having high sulfur resistance and high denitration rate.
A preparation method of activated carbon with high sulfur resistance and high denitration rate comprises the following steps:
1) mixing raw material coal, asphalt and metal ore, then optionally adding a binder and water, mixing, and uniformly mixing to obtain a mixed raw material;
1a) extruding and molding the mixed raw materials to obtain an active carbon precursor molding material;
1b) drying the active carbon precursor molding material to obtain a dried material;
2) adding the dried material into a carbonization furnace for carbonization to obtain a carbonized material;
3) and adding the carbonized material into an activation furnace for activation to obtain the activated carbon with high sulfur resistance and high denitration rate.
In the present invention, the method further comprises:
4) cooling and screening the activated high-sulfur-resistance high-denitration-rate activated carbon to obtain large-particle high-sulfur-resistance high-denitration-rate activated carbon;
5) and (3) returning the small-particle activated carbon (namely crushed material) obtained after cooling and screening to the step 1) for reuse or grinding into powder activated carbon.
The size of the large-particle activated carbon with high sulfur resistance and high denitration rate in the step 4) is 4-12 mm.
In the present invention, the metal ore in step 1) is an iron-containing ore. Preferably one or more of iron manganese ore, iron copper ore, iron titanium ore and iron tungsten ore. The binder is one or more of coal tar, carboxymethyl cellulose, polyvinyl alcohol and sesbania powder.
In the present invention, the metal ore is not limited, but is generally an iron-containing ore, and is a multi-metal compound, such as a ferromanganese ore, a ferromagnetite ore, a ferrotitanium ore, a ferrotungsten ore, and the like. Among them, active components in the metal ore, such as Mn, Cu, Ti, W, etc., can improve the denitration rate of the activated carbon, while Fe is mainly used for sulfur resistance.
Preferably, the ratio of the amount of the metal ore added to the amount of the raw coal added (i.e., the mass of the raw coal) in step 1) is a. Wherein: 0 < a.ltoreq.15%, preferably 0.1% < a.ltoreq.10%, more preferably 0.5% < a.ltoreq.8%.
In the invention, in the step 2), the concentration of CO in the carbonization furnace is controlled during the carbonization process. Preferably, the concentration of CO in the carbonization furnace is controlled to be b by regulating the addition amount of the fuel (such as coal powder or coal gas) from the heat source of the carbonization furnace, wherein: 0 < b.ltoreq.45%, preferably 0.1% < b.ltoreq.40%, more preferably 0.5% < b.ltoreq.37%.
Preferably, in the step 2), the concentration of oxygen in the carbonization furnace is controlled during carbonization. Preferably, the oxygen concentration in the carbonization furnace is controlled to be c by regulating the supplement amount of oxygen-containing gas (such as air) in the carbonization furnace, wherein: 0 < c.ltoreq.17%, preferably 0.1% < c.ltoreq.15%, more preferably 0.5% < c.ltoreq.12%.
In the invention, mixed gas of water vapor and oxygen is introduced into the activation furnace in the activation reaction process in the step 3). Preferably, the volume fraction of the oxygen amount in the mixed gas to the water vapor amount is 0.1 to 5%, preferably 0.3 to 4%, and more preferably 0.5 to 3%.
In the invention, the step 1) is specifically as follows: respectively grinding raw material coal, asphalt and metal ore into powder, mixing, optionally adding a binder and water, mixing, and uniformly mixing to obtain a mixed raw material. Preferably, the milling is performed by milling the raw material coal, the pitch, and the metal ore so that 90% or more of the raw material coal, the pitch, and the metal ore pass through 200 meshes, preferably 95% or more of the raw material coal, the pitch, and the metal ore pass through 200 meshes, and more preferably 97% or more of the raw material coal, the pitch, and the metal ore pass through 200 meshes.
Preferably, the milling is performed by milling the raw material coal, the pitch, and the metal ore so that 70% or more of the raw material coal, the pitch, and the metal ore pass through 325 mesh, preferably 75% or more of the raw material coal, the pitch, and the metal ore pass through 325 mesh, and more preferably 80% or more of the raw material coal, the pitch, and the metal ore pass through 325 mesh.
Preferably, the carbonization temperature in the step 2) is 300-1000 ℃, preferably 400-950 ℃, and more preferably 500-900 ℃. The carbonization time in the step 2) is 15-180 min, preferably 20-120 min, and more preferably 30-90 min.
Preferably, the temperature range of the activation reaction in the step 3) is 700-1100 ℃, preferably 800-1000 ℃, and more preferably 850-950 ℃. The time of the activation reaction in the step 3) is 20-240 min, preferably 30-180 min, and more preferably 40-120 min.
In the present invention, the mixing in step 1) is carried out by intensive mixing using an intensive mixer. Preferably, the intensive mixer is a vertical intensive mixer or a horizontal intensive mixer;
preferably, the degree of mixing of the mixed raw materials in step 1) is 75% or more, preferably 80% or more, and more preferably 85% or more.
In the invention, the shape of the active carbon precursor molding material in the step 1a) is one or more of spherical, cylindrical and rectangular. Preferably, the shape of the active carbon precursor molding material is cylindrical, and the size of the cylindrical active carbon precursor molding material is 4-12 mm, preferably 4.5-11 mm, and more preferably 5-10 mm.
Preferably, the activated carbon precursor molding material is dried in step 1b) to a moisture content of less than 15%, preferably less than 10%, more preferably less than 8%.
According to a second embodiment of the present invention, there is provided a method for preparing activated carbon having high sulfur resistance and high denitrification rate.
A preparation method of activated carbon with high sulfur resistance and high denitration rate comprises the following steps:
1) mixing raw material coal, asphalt and metal ore, then optionally adding a binder and water, mixing, and uniformly mixing to obtain a mixed raw material;
1a) extruding and molding the mixed raw materials to obtain an active carbon precursor molding material;
1b) drying the active carbon precursor molding material to obtain a dried material;
2) adding the dried material into a carbonization furnace for carbonization to obtain a carbonized material;
3) adding the carbonized material into an activation furnace for activation to obtain an activated material;
4) and (3) grinding the activated material to obtain the powdered activated carbon with high sulfur resistance and high denitration rate.
In the present invention, the activated carbon can be obtained in a powder form having a desired particle diameter by pulverizing the activated material.
In the present invention, the metal ore in step 1) is an iron-containing ore. Preferably one or more of iron manganese ore, iron copper ore, iron titanium ore and iron tungsten ore. The binder is one or more of coal tar, carboxymethyl cellulose, polyvinyl alcohol and sesbania powder.
Preferably, the ratio of the addition amount of the metal ore to the addition amount of the raw coal in the step 1) is a. Wherein: 0 < a.ltoreq.15%, preferably 0.1% < a.ltoreq.10%, more preferably 0.5% < a.ltoreq.8%.
In the invention, in the step 2), the concentration of CO in the carbonization furnace is controlled during the carbonization process. Preferably, the concentration of CO in the carbonization furnace is controlled to be b by regulating the addition amount of the fuel (such as coal powder or coal gas) from the heat source of the carbonization furnace, wherein: 0 < b.ltoreq.45%, preferably 0.1% < b.ltoreq.40%, more preferably 0.5% < b.ltoreq.37%.
Preferably, in the step 2), the concentration of oxygen in the carbonization furnace is controlled during carbonization. Preferably, the oxygen concentration in the carbonization furnace is controlled to be c by regulating the supplement amount of oxygen-containing gas (such as air) in the carbonization furnace, wherein: 0 < c.ltoreq.17%, preferably 0.1% < c.ltoreq.15%, more preferably 0.5% < c.ltoreq.12%.
In the invention, mixed gas of water vapor and oxygen is introduced into the activation furnace in the activation reaction process in the step 3). Preferably, the volume fraction of the oxygen amount in the mixed gas to the water vapor amount is 0.1 to 5%, preferably 0.3 to 4%, and more preferably 0.5 to 3%.
In the invention, the step 1) is specifically as follows: respectively grinding raw material coal, asphalt and metal ore into powder, mixing, optionally adding a binder and water, mixing, and uniformly mixing to obtain a mixed raw material. Preferably, the milling is performed by milling the raw material coal, the pitch, and the metal ore so that 90% or more of the raw material coal, the pitch, and the metal ore pass through 200 meshes, preferably 95% or more of the raw material coal, the pitch, and the metal ore pass through 200 meshes, and more preferably 97% or more of the raw material coal, the pitch, and the metal ore pass through 200 meshes.
Preferably, the milling is performed by milling the raw material coal, the pitch, and the metal ore so that 70% or more of the raw material coal, the pitch, and the metal ore pass through 325 mesh, preferably 75% or more of the raw material coal, the pitch, and the metal ore pass through 325 mesh, and more preferably 80% or more of the raw material coal, the pitch, and the metal ore pass through 325 mesh.
Preferably, the carbonization temperature in the step 2) is 300-1000 ℃, preferably 400-950 ℃, and more preferably 500-900 ℃. The carbonization time in the step 2) is 15-180 min, preferably 20-120 min, and more preferably 30-90 min.
Preferably, the temperature range of the activation reaction in the step 3) is 700-1100 ℃, preferably 800-1000 ℃, and more preferably 850-950 ℃. The time of the activation reaction in the step 3) is 20-240 min, preferably 30-180 min, and more preferably 40-120 min.
In the present invention, the mixing in step 1) is carried out by intensive mixing using an intensive mixer. Preferably, the intensive mixer is a vertical intensive mixer or a horizontal intensive mixer;
preferably, the degree of mixing of the mixed raw materials in step 1) is 75% or more, preferably 80% or more, and more preferably 85% or more.
In the invention, the shape of the active carbon precursor molding material in the step 1a) is one or more of spherical, cylindrical and rectangular. Preferably, the shape of the active carbon precursor molding material is cylindrical, and the size of the cylindrical active carbon precursor molding material is 4-12 mm, preferably 4.5-11 mm, and more preferably 5-10 mm.
Preferably, the activated carbon precursor molding material is dried in step 1b) to a moisture content of less than 15%, preferably less than 10%, more preferably less than 8%.
According to a third embodiment of the present invention, there is provided an activated carbon having high sulfur resistance and high denitration rate.
An activated carbon with high sulfur resistance and high denitration rate, wherein: the activated carbon with high sulfur resistance and high denitration rate is prepared according to the method.
The prior art is when adopting activated carbon method SOx/NOx control, the active carbon can play the effect of adsorbent and catalyst simultaneously, spout into the ammonia under certain conditions after, nitrogen oxide in the flue gas can react with the ammonia and generate nitrogen gas and purify the discharge, but because the efficiency that uses SOx/NOx control active carbon to carry out the denitration is not high now, compare SCR catalysis denitration gap great, if can effectively improve the denitration reaction efficiency of active carbon, then can realize the effect of the high SOx/NOx control of active carbon integration, consequently, it is significant to develop the active carbon who has high denitration rate.
The invention provides the activated carbon with high sulfur resistance and high denitration rate and the preparation method thereof based on the phenomena and mechanisms that metal oxides in minerals can generate lattice remodeling in the activated carbon through deoxidation and oxidation in the high-temperature carbonization-activation process of the activated carbon, so that the porosity in the activated carbon is adjusted and catalytic active metal oxides are uniformly loaded. According to the invention, raw coal, iron ore, asphalt-based binder and water are reasonably proportioned, and are combined with strong mixing process equipment, the raw coal, asphalt and iron ore are uniformly mixed, and are molded and granulated by extrusion equipment, and then are sequentially subjected to CO-assisted carbonization and steam composite oxygen activation, so that the activated carbon with large specific surface area, uniform distribution of metal oxides, good sulfur resistance and high denitration efficiency is prepared. In addition, the invention also provides a method for preparing the powdered activated carbon with high sulfur resistance and high denitration rate, which comprises the step of grinding the activated carbon with large specific surface area, uniform distribution of metal oxides, good sulfur resistance and high denitration efficiency prepared in the process into powder, thereby obtaining the powdered activated carbon with required particle size.
The invention provides activated carbon with high sulfur resistance and high denitration rate and a preparation method thereof, wherein the technical process and the technical principle are briefly described as follows:
grinding and mixing: the hardness of the raw material coal, the asphalt and the metal ore are different, and the raw material coal, the asphalt and the metal ore are ground to be fine powder with a certain particle size by adopting different grinding processes and equipment (for example, the raw material coal, the asphalt and the metal ore are ground to be more than 95 percent and pass through 200 meshes, or the raw material coal, the asphalt and the metal ore are ground to be more than 70 percent and pass through 325 meshes); because the solid material has limited mixing degree, the fine solid material needs to be intensively mixed (the mixing degree reaches 80%) by an intensive mixer, and a mixture with uniformly distributed metal ore-coal powder-binder is obtained.
Molding: according to the application of the active carbon, the uniformly mixed material is pressurized to be changed into an active carbon precursor molding material with a certain shape. The active carbon precursor molding material with a certain shape refers to the appearance of active carbon, and can be spherical, cylindrical, rectangular and the like, preferably cylindrical, for example, the size of the cylindrical active carbon precursor molding material is 5-10 mm.
Thirdly, drying: the active carbon precursor forming material has higher water content and softer whole body, and can influence the porosity and the strength of the active carbon in the carbonization process, so that the performance of the active carbon can not meet the requirements. Therefore, the active carbon precursor molding material needs to be dried until the water content is lower than 8 percent before carbonization.
CO assisted carbonization: the carbonization process is a reducing atmosphere, and under the atmosphere condition, metal oxides such as iron oxide, manganese oxide, copper oxide, titanium oxide, tungsten oxide and the like in the ore can be reduced. But because the carbonization temperature is medium-high temperature, the metal oxide is not reduced into simple substance, but only reduced into low-valence oxide, such as iron oxide changed into Fe3O4And the manganese oxide becomes MnO. Solid carbon in the activated carbon can be used as a reducing agent to reduce the metal oxide and generate CO at the same time; CO carried in the flue gas and oxygen in the flue gas react with solid carbon to generate partial CO; the obtained solid carbon and CO can participate in the process of reducing the metal oxide, and the reaction process is as follows:
MeOn+C＝MeOn-1+CO (1)；
2C+O2＝2CO (2)；
MeOn+CO＝MeOn-1+CO2 (3)；
however, the excessive participation of solid carbon in the reduction reaction can cause the quality loss of the activated carbon, and simultaneously can affect the strength of the activated carbon, so that the reactions (1) and (2) need to be inhibited in order to reduce the consumption of the activated carbon, and the reduction of CO is stronger than that of the solid carbon, so that the CO can preferentially and rapidly promote the reduction reaction of the metal oxide; in addition, CO is in a gaseous state and can enter the inside of the active carbon precursor forming material in the carbonization process, so that the porosity of the finally carbonized active carbon is increased. In order to promote the reaction (3), the CO concentration in the atmosphere (for example, the CO concentration is 0.5-37%) can be adjusted by regulating the supply amount of the coal gas at the source of the carbonization heat source, meanwhile, the air supply amount is controlled to prevent the coal gas from over-burning, limited oxygen led into the carbonization furnace preferentially reacts with the volatile organic compounds to reduce the loss of solid carbon, and finally the purpose of rapidly reducing the metal oxides by the CO is achieved.
Hypoxia activation: the carbonized material needs further pore-forming activation by water vapor, so that the carbon reacts with the water vapor. Meanwhile, a certain amount of oxygen can be introduced into the water vapor in the activation process (for example, the oxygen amount in the activation furnace accounts for 0.1-3% of the water vapor amount), and in the high-temperature activation process, after the oxygen is added into the water vapor atmosphere, the oxidation reaction of the oxygen and the solid carbon has remarkable opening and hole expansion effects on the activated carbon particles, the micropores, the specific surface area and the pore volume of the activated carbon particles are increased rapidly, so that an active site and favorable conditions are provided for the reaction of the activated carbon particles and sufficient water vapor, and the synergistic effect is promoted to occur. Meanwhile, the low-valence oxide formed in the carbonization process can be oxidized by water vapor and oxygen, so that high-valence metal oxide is obtained, and the reaction process is as follows:
2C+O2＝2CO (4)；
C+H2O＝CO+H2 (5)；
MeOn+O2＝MeOn+2 (6)；
MeOn+H2O＝MeOn+1+H2 (7)；
due to the reduction, activation and oxidation of the carbonization, the metal oxide in the activated carbon is subjected to the reduction and oxidation processes, the metal oxide is subjected to lattice remodeling, the internal porosity of the activated carbon is increased, and if MnO is generated in the reduction process2Conversion to Mn2O3In the meantime, volume expansion of the mineral phase occurs, from Mn2O3Conversion to Mn3O4And MnO shrinkage in volume can occur; and in the oxidation process, from MnO to MnO2Then volume expansion occurs, therebyThe activated carbon with high porosity and specific surface area is obtained. Meanwhile, the powerful mixing equipment and the process ensure that the coal powder and the ore are fully and uniformly mixed when the raw materials are mixed, and the metal oxide in the finally obtained activated carbon product is uniformly dispersed.
In the present invention, a uniform mixture of metal ore-pulverized coal-binder is formed by directly adding metal ore to the initial raw material for preparing activated carbon, and mixing. Since the metal ore is often rich in various metal oxides, the metal oxides in the metal ore are reduced to lower-priced metal oxides in the carbonization process and then oxidized to higher-priced metal oxides in the activation process in the preparation process of the activated carbon. In the whole preparation process of the activated carbon, the metal oxide undergoes a reduction-oxidation process, the crystal structure of the metal oxide is reformed, and the metal oxide and C in the coal powder in the raw material are recrystallized to form a high-strength metal oxide-C substance, so that the uniform, stable and high-strength activated carbon doped with the metal oxide is finally obtained.
Compared with the prior art, the method for preparing the doped active carbon by adding the soluble metal salt into the raw material of the active carbon or by an impregnation method, the metal oxide and C in the prepared active carbon doped with the metal oxide are recrystallized, and compared with the process of directly adding the soluble salt, the method has the advantages that the chemical bond between the metal oxide and the C atom is firmer, the gap between the metal oxide and the C atom is smaller, and the acting force of the connecting bond is larger, so that the high-strength active carbon doped with the metal oxide is formed. The active carbon prepared by the method is used for desulfurization and denitrification of the active carbon, and the active ions of the metal oxide are not easy to fall off due to the firm connection between the metal oxide and the C; because the active carbon needs to be circulated between the adsorption tower and the desorption tower for multiple times in the using process, after multiple tests, the metal oxide in the active carbon prepared by the invention can still be tightly combined in the active carbon, and still has the effects of high sulfur resistance and catalytic denitration.
In the research process, the samples which are retrieved from the engineering site and subjected to cyclic adsorption and desorption are tested to find that the desulfurization and denitrification performance is enhanced relative to that of the fresh samples, namely the cyclic desulfurization and denitrification performance of the activated carbon is enhanced. The activated carbon is continuously treated by high temperature and acidic environment in the cyclic adsorption and desorption process, so that the quantity and specific surface area of functional groups in the activated carbon are enhanced, more sulfur oxides and nitrogen oxides can be adsorbed, more adsorption catalytic reactions can be generated, and the desulfurization and denitrification effects are enhanced. Meanwhile, the addition of the metal ore increases the active catalytic sites in the activated carbon, and if the compound of Fe, Mn and O does not react with sulfur dioxide to be passivated in the cyclic adsorption and desorption process, the catalytic effect is always maintained; in addition, the presence of Fe preferentially reacts with sulfur dioxide and the like, and also prevents the manganese oxide having a catalytic activity from being passivated, thereby providing high sulfur resistance and high denitration effects.
Through experimental comparison, the active carbon prepared by adding the metal soluble salt into the raw material of the active carbon is used for the desulfurization and denitrification process of the adsorption tower and the desorption tower, and the change of the sulfur resistance and the denitrification efficiency of the active carbon is not large (or is not obviously increased) after 3 times of circulation. Similarly, the doped activated carbon prepared by the impregnation method is used in the desulfurization and denitrification process of the adsorption tower-desorption tower because the metal compound is only attached to the surface of the activated carbon, and the sulfur resistance and the denitrification efficiency of the activated carbon are not basically increased after 3 times of circulation. In the prior art, the metal oxide which is commonly dissolved or impregnated is easy to wear off due to insufficient binding force, so that the desulfurization and denitrification effects are not obviously improved in the circulating process. The activated carbon prepared by the process is used for the desulfurization and denitrification process of the adsorption tower and the desorption tower, and the denitrification efficiency of the activated carbon is improved by 6.28 percent after 3 times of circulation. The activated carbon prepared by the process is used for the desulfurization and denitrification process of the adsorption tower and the desorption tower, and the denitrification efficiency of the activated carbon is improved by 36.14 percent after 10 times of circulation. In the activated carbon prepared by the invention, metal ores are added by grinding and heat treatment reaction is carried out, so that a chemical bond with larger acting force is formed between metal oxide and C, the bonding force between the metal oxide and C atoms is stronger, gaps are smaller, the amount of the metal oxide stored in the activated carbon is larger, the storage time is longer, the distribution of the metal oxide is gradually more uniform along with the change of the crystal structure and the specific surface area of the metal oxide in the activated carbon, and the exposed active sites are gradually increased, so that the desulfurization and denitrification effects are more obviously increased after cyclic adsorption and analysis.
In addition, in the preparation process of the activated carbon, the raw materials are added with the metal ore, and the metal oxide in the metal ore is sequentially reduced and oxidized in the carbonization and activation processes. In each change process, the crystal structure of the metal oxide changes, and the change externally shows that the volume of the metal oxide changes. In the forming process of the activated carbon, the volume change of the metal oxide can promote the formation of the active carbon gap, and the hole opening and hole expansion effects on the active carbon are obvious. Therefore, the crystal form change of the metal oxide promotes the formation of the gaps of the activated carbon, and the specific surface area and the active catalytic sites of the activated carbon are improved, so that the desulfurization and denitrification efficiency of the activated carbon is improved.
In the invention, the concentration of CO in the carbonization furnace is controlled by regulating the addition amount of the source fuel (such as coal powder or coal gas) of the heat source of the carbonization furnace, and the concentration of oxygen in the carbonization furnace is controlled by regulating the supplement amount of oxygen-containing gas (such as air) of the carbonization furnace, so that the limited oxygen in the carbonization furnace is preferentially reacted with volatile organic compounds in the coal powder as the raw material of the activated carbon to reduce the loss of solid carbon, and the formed CO is beneficial to the reduction of metal oxides, and finally the aim of rapidly reducing the metal oxides by the CO is achieved.
In this application, "optionally" means with or without.
Compared with the prior art, the invention has the following beneficial technical effects:
1. according to the invention, metal ore is added from the source, and the form of metal oxide in the activated carbon is regulated and controlled by adopting strong mixing equipment and a process and simultaneously controlling the carbonization and activation reaction conditions, so that the specific surface area of the activated carbon is increased while the uniform distribution and the activation of the metal oxide are realized, and finally the activated carbon loaded with uniform metal oxide and high specific surface area is obtained;
2. according to the invention, metal ore is directly added into the preparation raw material, the metal oxide in the metal ore undergoes the reduction-oxidation process, the crystal structure is reformed, and the crystal structure and C in the coal powder are recrystallized to form a high-strength metal oxide-C substance, so that the stable and high-strength active carbon doped with the metal oxide is finally obtained;
3. according to the invention, the metal ore is directly added into the preparation raw material, and the metal salt is not required to be converted into a solution state, so that the method has the advantages of short process and low investment, is easy for industrial application, can realize continuous and stable production of the desulfurization and denitrification active carbon, and has remarkable economic and social benefits;
4. the added metal ore is iron-containing ore, and the ore is a multi-metal compound, so that the active carbon containing the compound can be finally formed, the active carbon has the advantages of sulfur resistance and denitration rate improvement in the practical process, wherein the active components in the metal ore, such as Mn, Ti, Cu, W and the like, can improve the denitration rate, and Fe is mainly used for sulfur resistance;
5. the concentration of CO is controlled by regulating the supplement amount of coal gas and air in the carbonization process, the existing process and equipment are fully utilized for improvement, new energy and devices are not required to be additionally added, and the method is easy for industrial application and popularization;
6. compared with common activated carbon, the activated carbon prepared by the invention has high sulfur resistance and high denitration rate, and the performance of the activated carbon prepared by the invention still keeps a stable level after repeated circulating desulfurization and denitration.
Drawings
FIG. 1 is a flow diagram of a conventional activated carbon preparation process;
FIG. 2 is a flow chart of a preparation method for improving the denitration rate of activated carbon in the prior art;
FIG. 3 is a flow chart of another preparation method for improving the denitration rate of activated carbon in the prior art;
FIG. 4 is a flow chart of a method for preparing activated carbon with high sulfur resistance and high denitration rate according to the present invention;
FIG. 5 is a flow chart of a method for preparing powdered activated carbon having high sulfur resistance and high denitrification rate according to the present invention.
Detailed Description
According to a first embodiment of the present invention, there is provided a method for producing activated carbon having high sulfur resistance and high denitration rate.
A preparation method of activated carbon with high sulfur resistance and high denitration rate comprises the following steps:
1) mixing raw material coal, asphalt and metal ore, then optionally adding a binder and water, mixing, and uniformly mixing to obtain a mixed raw material;
1a) extruding and molding the mixed raw materials to obtain an active carbon precursor molding material;
1b) drying the active carbon precursor molding material to obtain a dried material;
2) adding the dried material into a carbonization furnace for carbonization to obtain a carbonized material;
3) and adding the carbonized material into an activation furnace for activation to obtain the activated carbon with high sulfur resistance and high denitration rate.
In the present invention, the method further comprises:
4) cooling and screening the activated high-sulfur-resistance high-denitration-rate activated carbon to obtain large-particle high-sulfur-resistance high-denitration-rate activated carbon;
5) and (3) returning the small-particle activated carbon obtained after cooling and screening to the step 1) for reuse or grinding into powder activated carbon.
The size of the large-particle activated carbon with high sulfur resistance and high denitration rate in the step 4) is 4-12 mm.
In the present invention, the metal ore in step 1) is an iron-containing ore. Preferably one or more of iron manganese ore, iron copper ore, iron titanium ore and iron tungsten ore. The binder is one or more of coal tar, carboxymethyl cellulose, polyvinyl alcohol and sesbania powder.
Preferably, the ratio of the addition amount of the metal ore to the addition amount of the raw coal in the step 1) is a. Wherein: 0 < a.ltoreq.15%, preferably 0.1% < a.ltoreq.10%, more preferably 0.5% < a.ltoreq.8%.
In the invention, in the step 2), the concentration of CO in the carbonization furnace is controlled during the carbonization process. Preferably, the concentration of CO in the carbonization furnace is controlled to be b by regulating the addition amount of the fuel (such as coal powder or coal gas) from the heat source of the carbonization furnace, wherein: 0 < b.ltoreq.45%, preferably 0.1% < b.ltoreq.40%, more preferably 0.5% < b.ltoreq.37%.
Preferably, in the step 2), the concentration of oxygen in the carbonization furnace is controlled during carbonization. Preferably, the oxygen concentration in the carbonization furnace is controlled to be c by regulating the supplement amount of oxygen-containing gas (such as air) in the carbonization furnace, wherein: 0 < c.ltoreq.17%, preferably 0.1% < c.ltoreq.15%, more preferably 0.5% < c.ltoreq.12%.
In the invention, mixed gas of water vapor and oxygen is introduced into the activation furnace in the activation reaction process in the step 3). Preferably, the volume fraction of the oxygen amount in the mixed gas to the water vapor amount is 0.1 to 5%, preferably 0.3 to 4%, and more preferably 0.5 to 3%.
In the invention, the step 1) is specifically as follows: respectively grinding raw material coal, asphalt and metal ore into powder, mixing, optionally adding a binder and water, mixing, and uniformly mixing to obtain a mixed raw material. Preferably, the milling is performed by milling the raw material coal, the pitch, and the metal ore so that 90% or more of the raw material coal, the pitch, and the metal ore pass through 200 meshes, preferably 95% or more of the raw material coal, the pitch, and the metal ore pass through 200 meshes, and more preferably 97% or more of the raw material coal, the pitch, and the metal ore pass through 200 meshes.
Preferably, the milling is performed by milling the raw material coal, the pitch, and the metal ore so that 70% or more of the raw material coal, the pitch, and the metal ore pass through 325 mesh, preferably 75% or more of the raw material coal, the pitch, and the metal ore pass through 325 mesh, and more preferably 80% or more of the raw material coal, the pitch, and the metal ore pass through 325 mesh.
Preferably, the carbonization temperature in the step 2) is 300-1000 ℃, preferably 400-950 ℃, and more preferably 500-900 ℃. The carbonization time in the step 2) is 15-180 min, preferably 20-120 min, and more preferably 30-90 min.
Preferably, the temperature range of the activation reaction in the step 3) is 700-1100 ℃, preferably 800-1000 ℃, and more preferably 850-950 ℃. The time of the activation reaction in the step 3) is 20-240 min, preferably 30-180 min, and more preferably 40-120 min.
In the present invention, the mixing in step 1) is carried out by intensive mixing using an intensive mixer. Preferably, the intensive mixer is a vertical intensive mixer or a horizontal intensive mixer;
preferably, the degree of mixing of the mixed raw materials in step 1) is 75% or more, preferably 80% or more, and more preferably 85% or more.
In the invention, the shape of the active carbon precursor molding material in the step 1a) is one or more of spherical, cylindrical and rectangular. Preferably, the shape of the active carbon precursor molding material is cylindrical, and the size of the cylindrical active carbon precursor molding material is 4-12 mm, preferably 4.5-11 mm, and more preferably 5-10 mm.
Preferably, the activated carbon precursor molding material is dried in step 1b) to a moisture content of less than 15%, preferably less than 10%, more preferably less than 8%.
According to a second embodiment of the present invention, there is provided a method for preparing activated carbon having high sulfur resistance and high denitrification rate.
A preparation method of activated carbon with high sulfur resistance and high denitration rate comprises the following steps:
1) mixing raw material coal, asphalt and metal ore, then optionally adding a binder and water, mixing, and uniformly mixing to obtain a mixed raw material;
1a) extruding and molding the mixed raw materials to obtain an active carbon precursor molding material;
1b) drying the active carbon precursor molding material to obtain a dried material;
2) adding the dried material into a carbonization furnace for carbonization to obtain a carbonized material;
3) adding the carbonized material into an activation furnace for activation to obtain an activated material;
4) and (3) grinding the activated material to obtain the powdered activated carbon with high sulfur resistance and high denitration rate.
In the present invention, the metal ore in step 1) is an iron-containing ore. Preferably one or more of iron manganese ore, iron copper ore, iron titanium ore and iron tungsten ore. The binder is one or more of coal tar, carboxymethyl cellulose, polyvinyl alcohol and sesbania powder.
Preferably, the ratio of the addition amount of the metal ore to the addition amount of the raw coal in the step 1) is a. Wherein: 0 < a.ltoreq.15%, preferably 0.1% < a.ltoreq.10%, more preferably 0.5% < a.ltoreq.8%.
In the invention, in the step 2), the concentration of CO in the carbonization furnace is controlled during the carbonization process. Preferably, the concentration of CO in the carbonization furnace is controlled to be b by regulating the addition amount of the fuel (such as coal powder or coal gas) from the heat source of the carbonization furnace, wherein: 0 < b.ltoreq.45%, preferably 0.1% < b.ltoreq.40%, more preferably 0.5% < b.ltoreq.37%.
Preferably, in the step 2), the concentration of oxygen in the carbonization furnace is controlled during carbonization. Preferably, the oxygen concentration in the carbonization furnace is controlled to be c by regulating the supplement amount of oxygen-containing gas (such as air) in the carbonization furnace, wherein: 0 < c.ltoreq.17%, preferably 0.1% < c.ltoreq.15%, more preferably 0.5% < c.ltoreq.12%.
In the invention, mixed gas of water vapor and oxygen is introduced into the activation furnace in the activation reaction process in the step 3). Preferably, the volume fraction of the oxygen amount in the mixed gas to the water vapor amount is 0.1 to 5%, preferably 0.3 to 4%, and more preferably 0.5 to 3%.
In the invention, the step 1) is specifically as follows: respectively grinding raw material coal, asphalt and metal ore into powder, mixing, optionally adding a binder and water, mixing, and uniformly mixing to obtain a mixed raw material. Preferably, the milling is performed by milling the raw material coal, the pitch, and the metal ore so that 90% or more of the raw material coal, the pitch, and the metal ore pass through 200 meshes, preferably 95% or more of the raw material coal, the pitch, and the metal ore pass through 200 meshes, and more preferably 97% or more of the raw material coal, the pitch, and the metal ore pass through 200 meshes.
Preferably, the milling is performed by milling the raw material coal, the pitch, and the metal ore so that 70% or more of the raw material coal, the pitch, and the metal ore pass through 325 mesh, preferably 75% or more of the raw material coal, the pitch, and the metal ore pass through 325 mesh, and more preferably 80% or more of the raw material coal, the pitch, and the metal ore pass through 325 mesh.
Preferably, the carbonization temperature in the step 2) is 300-1000 ℃, preferably 400-950 ℃, and more preferably 500-900 ℃. The carbonization time in the step 2) is 15-180 min, preferably 20-120 min, and more preferably 30-90 min.
Preferably, the temperature range of the activation reaction in the step 3) is 700-1100 ℃, preferably 800-1000 ℃, and more preferably 850-950 ℃. The time of the activation reaction in the step 3) is 20-240 min, preferably 30-180 min, and more preferably 40-120 min.
In the present invention, the mixing in step 1) is carried out by intensive mixing using an intensive mixer. Preferably, the intensive mixer is a vertical intensive mixer or a horizontal intensive mixer;
preferably, the degree of mixing of the mixed raw materials in step 1) is 75% or more, preferably 80% or more, and more preferably 85% or more.
In the invention, the shape of the active carbon precursor molding material in the step 1a) is one or more of spherical, cylindrical and rectangular. Preferably, the shape of the active carbon precursor molding material is cylindrical, and the size of the cylindrical active carbon precursor molding material is 4-12 mm, preferably 4.5-11 mm, and more preferably 5-10 mm.
Preferably, the activated carbon precursor molding material is dried in step 1b) to a moisture content of less than 15%, preferably less than 10%, more preferably less than 8%.
According to a third embodiment of the present invention, there is provided an activated carbon having high sulfur resistance and high denitration rate.
An activated carbon with high sulfur resistance and high denitration rate, wherein: the activated carbon with high sulfur resistance and high denitration rate is prepared according to the method.
Example 1
A preparation method of activated carbon with high sulfur resistance and high denitration rate comprises the following steps:
1) mixing raw material coal, asphalt and metal ore, adding a binder and water, mixing, and uniformly mixing to obtain a mixed raw material;
1a) extruding and molding the mixed raw materials to obtain an active carbon precursor molding material;
1b) drying the active carbon precursor molding material to obtain a dried material;
2) adding the dried material into a carbonization furnace for carbonization to obtain a carbonized material;
3) and adding the carbonized material into an activation furnace for activation to obtain the activated carbon with high sulfur resistance and high denitration rate.
Example 2
Example 1 is repeated except that the method further comprises:
4) cooling and screening the activated high-sulfur-resistance high-denitration-rate activated carbon to obtain large-particle high-sulfur-resistance high-denitration-rate activated carbon;
5) and (3) returning the small-particle activated carbon obtained after cooling and screening to the step 1) for reuse.
Example 3
A preparation method of activated carbon with high sulfur resistance and high denitration rate comprises the following steps:
1) mixing raw material coal, asphalt and metal ore, adding a binder and water, mixing, and uniformly mixing to obtain a mixed raw material;
1a) extruding and molding the mixed raw materials to obtain an active carbon precursor molding material;
1b) drying the active carbon precursor molding material to obtain a dried material;
2) adding the dried material into a carbonization furnace for carbonization to obtain a carbonized material;
3) adding the carbonized material into an activation furnace for activation to obtain an activated material;
4) and (3) grinding the activated material to obtain the powdered activated carbon with high sulfur resistance and high denitration rate.
Example 4
As shown in fig. 4, a method for preparing activated carbon with high sulfur resistance and high denitration rate comprises the following steps:
1) respectively grinding raw material coal, asphalt and metal ore into powder, mixing, adding a binder and water, mixing, and uniformly mixing to obtain a mixed raw material.
Wherein, the milling is to mill the raw material coal, the asphalt and the metal ore respectively until more than 95 percent of the raw material coal, the asphalt and the metal ore pass through 200 meshes. The mixing is carried out by adopting a vertical intensive mixer. The blending degree of the mixed raw materials is more than or equal to 80 percent. The metal ore is a ferro manganese ore. The binder is coal tar. The addition amount of the iron-manganese ore accounts for 5% of the addition amount of the raw material coal.
1a) And extruding and forming the mixed raw materials to obtain the active carbon precursor molding material. The shape of the active carbon precursor molding material is cylindrical, and the size of the cylindrical active carbon precursor molding material is 8-10 mm.
1b) And drying the active carbon precursor molding material to obtain a dried material. And drying the active carbon precursor molding material until the water content is lower than 8%.
2) And adding the dried material into a carbonization furnace for carbonization to obtain a carbonized material.
Wherein, in the carbonization process, the concentration of CO in the carbonization furnace is controlled. The concentration of CO in the carbonization furnace is controlled to be 35 percent by regulating and controlling the addition amount of coal gas from a heat source of the carbonization furnace. Meanwhile, in the carbonization process, the concentration of oxygen in the carbonization furnace is controlled, and the concentration of oxygen in the carbonization furnace is controlled to be 3% by regulating and controlling the air supplement amount of the carbonization furnace. The carbonization temperature is 700 ℃, and the carbonization time is 80 min.
3) And adding the carbonized material into an activation furnace for activation to obtain the activated carbon with high sulfur resistance and high denitration rate.
Introducing mixed gas of water vapor and oxygen into the activation furnace during the activation reaction process. Wherein the volume fraction of the oxygen amount in the mixed gas in the water vapor amount is 2%. The temperature of the activation reaction is 900 ℃, and the time of the activation reaction is 90 min.
4) After the activated high-sulfur-resistance high-denitration-rate activated carbon is cooled and screened, large-particle high-sulfur-resistance high-denitration-rate activated carbon is obtained, and the particle size of the activated carbon is 8-10 mm.
5) And (3) returning the small-particle activated carbon obtained after cooling and screening to the step 1) for reuse.
Example 5
As shown in fig. 5, a method for preparing activated carbon with high sulfur resistance and high denitration rate comprises the following steps:
1) respectively grinding raw material coal, asphalt and metal ore into powder, mixing, adding a binder and water, mixing, and uniformly mixing to obtain a mixed raw material.
Wherein, the milling is to mill the raw material coal, the asphalt and the metal ore respectively until more than 95 percent of the raw material coal, the asphalt and the metal ore pass through 200 meshes. The mixing is carried out by adopting a vertical intensive mixer. The blending degree of the mixed raw materials is more than or equal to 80 percent. The metal ore is a ferro manganese ore. The binder is coal tar. The addition amount of the iron-manganese ore accounts for 5% of the addition amount of the raw material coal.
1a) And extruding and forming the mixed raw materials to obtain the active carbon precursor molding material. The shape of the active carbon precursor molding material is cylindrical, and the size of the cylindrical active carbon precursor molding material is 8-10 mm.
1b) And drying the active carbon precursor molding material to obtain a dried material. And drying the active carbon precursor molding material until the water content is lower than 8%.
2) And adding the dried material into a carbonization furnace for carbonization to obtain a carbonized material.
Wherein, in the carbonization process, the concentration of CO in the carbonization furnace is controlled. The concentration of CO in the carbonization furnace is controlled to be 35 percent by regulating and controlling the addition amount of coal gas from a heat source of the carbonization furnace. Meanwhile, in the carbonization process, the concentration of oxygen in the carbonization furnace is controlled, and the concentration of oxygen in the carbonization furnace is controlled to be 3% by regulating and controlling the air supplement amount of the carbonization furnace. The carbonization temperature is 700 ℃, and the carbonization time is 80 min.
3) And adding the carbonized material into an activation furnace for activation to obtain an activated material.
Introducing mixed gas of water vapor and oxygen into the activation furnace during the activation reaction process. Wherein the volume fraction of the oxygen amount in the mixed gas in the water vapor amount is 2%. The temperature of the activation reaction is 900 ℃, and the time of the activation reaction is 90 min.
4) And (3) grinding the activated material to obtain the powdered activated carbon with high sulfur resistance and high denitration rate, wherein the particle size of the activated carbon is less than or equal to 1 mm.
Example 6
Example 4 was repeated except that in step 5), the small-sized activated carbon obtained after cooling and sieving was pulverized into powdered activated carbon.
Example 7
Example 4 was repeated except that the metal ore in step 1) was a ferrierite ore. The addition amount of the iron-titanium ore accounts for 4% of the addition amount of the raw material coal.
Example 8
Example 4 was repeated except that the milling in step 1) was carried out so that more than 70% of the raw material coal, pitch and metal ore passed through 325 mesh.
Example 9
Example 4 was repeated except that the concentration of CO in the retort was controlled to 30% by controlling the amount of coal gas added from the source of the heat source of the retort in step 2).
Example 10
Example 4 was repeated except that the mixed gas of water vapor and oxygen was introduced into the activation furnace during the activation reaction in step 3). The volume fraction of the oxygen amount in the mixed gas in the water vapor amount is 2.5%.
Example 11
Example 4 was repeated except that the temperature of the carbonization in step 2) was 650 ℃ and the time of carbonization was 120 min.
Example 12
Example 4 was repeated, except that the temperature of the activation reaction in step 3) was 850 ℃ and the time of the activation reaction was 120 min.
Comparative example 1
A preparation process of activated carbon comprises the following steps: grinding raw coal and asphalt into powder, mixing the powder with a binder and water, and then sequentially molding, drying, carbonizing, activating and grinding to obtain the finished product of the activated carbon powder. Wherein the relevant process conditions were the same as in example 5. The active carbon powder is finally prepared in the embodiment, and the particle size of the active carbon powder is less than or equal to 1 mm.
Comparative example 2
As shown in fig. 1, a preparation process of activated carbon specifically comprises the following steps: grinding raw coal and asphalt into powder, mixing the powder with a binder and water, and then sequentially molding, drying, carbonizing, activating, cooling and screening to obtain the finished product of the activated carbon. Wherein, the relevant process conditions are the same as in example 4.
Comparative example 3
As shown in fig. 2, a preparation process of activated carbon specifically comprises the following steps: grinding raw coal and asphalt into powder, dissolving metal salt into solution, mixing with a binder and water, and sequentially molding, drying, carbonizing, activating, cooling and screening to obtain the finished product of activated carbon. Wherein, the relevant process conditions are the same as in example 4.
Comparative example 4
As shown in fig. 3, a preparation process of activated carbon specifically comprises the following steps: grinding raw coal and asphalt into powder, mixing the powder with a binder and water, sequentially molding, drying, carbonizing and activating to obtain initial activated carbon, dissolving metal salt, soaking the activated initial activated carbon in a metal salt solution, sequentially calcining, cooling and screening to obtain the finished activated carbon. Wherein, the relevant process conditions are the same as in example 4.
The relevant data of the activated carbon prepared in each example is recorded, and the activated carbon prepared in each example is used for flue gas desulfurization and denitration through engineering tests, and the test results are as follows:
from the test results, compared with the common activated carbon, the activated carbon prepared by the method has high sulfur resistance and high denitration rate, and the performance of the activated carbon prepared by the method still keeps a stable level after repeated circulating desulfurization and denitration.