CN116272864A - Adsorbent for removing mercury and sulfur trioxide in flue gas and preparation method thereof - Google Patents

Adsorbent for removing mercury and sulfur trioxide in flue gas and preparation method thereof Download PDF

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Publication number
CN116272864A
CN116272864A CN202310165679.9A CN202310165679A CN116272864A CN 116272864 A CN116272864 A CN 116272864A CN 202310165679 A CN202310165679 A CN 202310165679A CN 116272864 A CN116272864 A CN 116272864A
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activated carbon
adsorbent
flue gas
modification
sulfur trioxide
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Inventor
王乐乐
白勇
雷嗣远
马云龙
鲍强
宋玉宝
孔凡海
姚燕
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Shanghai Huachuan Environmental Protection Technology Co ltd
Xian Thermal Power Research Institute Co Ltd
Suzhou Xire Energy Saving Environmental Protection Technology Co Ltd
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Shanghai Huachuan Environmental Protection Technology Co ltd
Xian Thermal Power Research Institute Co Ltd
Suzhou Xire Energy Saving Environmental Protection Technology Co Ltd
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Priority to CN202310165679.9A priority Critical patent/CN116272864A/en
Publication of CN116272864A publication Critical patent/CN116272864A/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
    • B01J20/02—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material
    • B01J20/20—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising free carbon; comprising carbon obtained by carbonising processes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/02—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
    • B01J20/02—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material
    • B01J20/04—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising compounds of alkali metals, alkaline earth metals or magnesium
    • B01J20/041—Oxides or hydroxides
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
    • B01J20/02—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material
    • B01J20/04—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising compounds of alkali metals, alkaline earth metals or magnesium
    • B01J20/046—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising compounds of alkali metals, alkaline earth metals or magnesium containing halogens, e.g. halides
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2253/00—Adsorbents used in seperation treatment of gases and vapours
    • B01D2253/10—Inorganic adsorbents
    • B01D2253/102—Carbon
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2253/00—Adsorbents used in seperation treatment of gases and vapours
    • B01D2253/10—Inorganic adsorbents
    • B01D2253/112—Metals or metal compounds not provided for in B01D2253/104 or B01D2253/106
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2257/00—Components to be removed
    • B01D2257/30—Sulfur compounds
    • B01D2257/302—Sulfur oxides
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2257/00—Components to be removed
    • B01D2257/60—Heavy metals or heavy metal compounds
    • B01D2257/602—Mercury or mercury compounds
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2220/00—Aspects relating to sorbent materials
    • B01J2220/40—Aspects relating to the composition of sorbent or filter aid materials
    • B01J2220/42—Materials comprising a mixture of inorganic materials
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2220/00—Aspects relating to sorbent materials
    • B01J2220/40—Aspects relating to the composition of sorbent or filter aid materials
    • B01J2220/48—Sorbents characterised by the starting material used for their preparation
    • B01J2220/4806—Sorbents characterised by the starting material used for their preparation the starting material being of inorganic character
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
    • Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters

Abstract

The invention provides an adsorbent for removing mercury and sulfur trioxide in flue gas and a preparation method thereof, and belongs to the technical field of flue gas purification treatment. The adsorbent comprises: the method comprises the steps of firstly atomizing the metal halide at a high temperature above 300 ℃ to perform first modification on the activated carbon, and then atomizing the alkali metal hydroxide at a low temperature between 150 and 300 ℃ to perform second modification on the activated carbon. The adsorbent sequentially activates and modifies the activated carbon by utilizing the metal halide and the alkali metal hydroxide, and loads the metal halide and the alkali metal hydroxide on the inner and outer surfaces of the micropores of the activated carbon, SO that the adsorbent can simultaneously remove Hg and SO in flue gas 3 And the metal halide during modificationThe alkali metal hydroxide is gasified, so that the use amount of chemicals is greatly reduced, and meanwhile, the excessive activation temperature is not required, thereby saving energy and cost.

Description

Adsorbent for removing mercury and sulfur trioxide in flue gas and preparation method thereof
Technical Field
The invention belongs to the technical field of flue gas purification treatment, and particularly relates to an adsorbent for removing mercury and sulfur trioxide in flue gas and a preparation method thereof.
Background
SO with the implementation of ultra-low emission modification of thermal power plants 2 NOx and soot emissions have been effectively controlled rather than the conventional pollutants Hg and SO 3 Will become a hot spot for the next stage of atmospheric pollutant remediation.
Currently, the Hg emission standard of the domestic thermal power plant is 0.03mg/m 3 While the U.S. emission limit was 0.0017mg/m 3 With the advancement of International ' Water ' convention ', the emission of Hg pollutants in thermal power plants is controlled more severely in the future in China, which is imperative.
Meanwhile, the United states has 22 states to coal-fired power plants SO 3 The emission limit is set to be generally controlled to be 0.6-20mg/m 3 Wherein 14 states have emission limits below 6mg/m 3 . In Beijing, the maximum allowable of organized sulfuric acid mist is required from the beginning of the year 2017, 3 and 1, as specified in the Integrated emission Standard of atmospheric pollutants (DB 11501-2017)The emission limit was 5mg/m 3 . The maximum allowable emission limit of the organized sulfuric acid mist required by the Shanghai city from the beginning of 1 st 2017 of the integrated emission Standard of atmospheric pollutants (DB 31/933-2015) is 5mg/m 3 . Although it is now for SO at home and abroad 3 Emissions have not set more stringent emissions limits, but because of the ultra low emissions modifications in coal-fired power plants, backup layer sorbents, SO, are commonly added 2 /SO 3 The increase in conversion increases the SO downstream of denitrification 3 Resulting in a corresponding SO concentration 3 (or NH) 4 HSO 4 ) The problem of corrosion blockage and pollution after discharge is further exacerbated and highlighted. According to the tests of domestic researchers, the actual flue gas SO of nearly 60 coal-fired units 3 The average value of the discharge concentration is 6.6-23 mg/m 3 . Therefore, this also gives SO to domestic coal-fired power plants 3 The control of contaminants presents new challenges.
Based on the actual environmental protection requirement and international environmental protection pressure, the implementation of stricter emission standards of mercury and sulfur trioxide in coal-fired flue gas in China, and even the adoption of control technology are very necessary. And the national "coal-electricity energy-saving and emission-reduction upgrading and reformation action plan" (2014-2020) clearly indicates that the simultaneous development of the combination of atmospheric pollutants and the simultaneous removal are supported, and the emission of pollutants such as sulfur trioxide, mercury and the like is reduced. It can be seen that Hg and SO are contained in the flue gas 3 Will become a hot spot for the treatment of the atmospheric pollutants in the next stage.
However, there are special applications in the market for removing Hg or SO 3 Without the adsorbent capable of efficiently adsorbing Hg and SO in flue gas simultaneously 3 Is contained in the adsorbent of (a). For example, patent application CN200680016613.8 provides a catalytic adsorbent formed by doping activated carbon with a dispersed halide salt, but the catalytic adsorbent can only be used for Hg removal and impregnation is employed. Patent application document CN109173687A discloses a method for removing sulfur trioxide in flue gas, which comprises the steps of mixing massive lime, a sodium-based absorbent and water according to a certain proportion, generating micron-sized calcium hydroxide particles in the mixing process of the massive lime and the water, and then mixing the micron-sized calcium hydroxide particles with the sodium-based absorbent to prepare the catalyst which is easy to react with the sulfur trioxideThe absorbent slurry is uniformly distributed in the flue gas to remove sulfur trioxide in the flue gas, but the absorbent slurry cannot remove heavy metal pollutants such as mercury in the flue gas.
Disclosure of Invention
The present invention has been made based on the findings and knowledge of the inventors regarding the following facts and problems: in the related art, hg or SO is mainly used 3 The removal of a single contaminant cannot realize the simultaneous removal of the two. Hg or SO in flue gas 3 Although the corresponding adsorbents can be used for removing, the reaction temperature range and the types of the adsorbents are completely different, and Hg and SO are removed 3 Two independent removal systems are needed, the system is complex, the investment and operation cost is high, and the simultaneous removal of the two systems cannot be realized. Therefore, development of an adsorbent for removing mercury and sulfur trioxide from flue gas and a preparation method thereof are needed, a removal system is simplified, and investment and operation cost are reduced.
The present invention aims to solve at least one of the technical problems in the related art to some extent. Therefore, the embodiment of the invention provides the adsorbent for removing mercury and sulfur trioxide in the flue gas and the preparation method thereof, and the adsorbent firmly attaches metal halides and hydroxides on the inner and outer surfaces of the activated carbon by utilizing the high temperature during the activation of the activated carbon, SO that the modified activated carbon has the advantages of high-efficiency Hg and SO removal 3 Is provided).
The adsorbent for removing mercury and sulfur trioxide in flue gas provided by the embodiment of the invention comprises the following components: the method comprises the steps of firstly atomizing the metal halide at a high temperature above 300 ℃ to perform first modification on the activated carbon, and then atomizing the alkali metal hydroxide at a low temperature between 150 and 300 ℃ to perform second modification on the activated carbon.
The adsorbent for removing mercury and sulfur trioxide in flue gas provided by the embodiment of the invention has the following advantages and technical effects:
(1) The adsorbent provided by the embodiment of the invention is provided with the activated carbon carrier, SO that the specific surface area of the adsorbent is increased, and Hg and SO are led to 3 The contact area with the adsorbent is larger, and the contact area is improvedThe adsorption and removal efficiency of the adsorbent;
(2) The adsorbent provided by the embodiment of the invention has the advantages that the metal halide and the alkali metal hydroxide are simultaneously loaded on the inner surface and the outer surface of the active carbon micropore, SO that the adsorbent has the function of simultaneously removing Hg and SO in flue gas 3 Is effective in (1);
(3) According to the adsorbent disclosed by the embodiment of the invention, the metal halide and the alkali metal hydroxide are directly attached to the inner and outer surfaces of the active carbon pores by adopting the conditions of high-temperature atomization and low-temperature atomization in sequence, so that chemical impregnation is not needed, the use amount of chemicals is greatly reduced, and meanwhile, the excessive activation temperature is not needed, so that the energy and the cost are saved.
In some embodiments, the activated carbon comprises at least one of coal activated carbon, wood activated carbon, coconut activated carbon.
In some embodiments, the activated carbon has a particle size of greater than 95% less than 100 mesh.
In some embodiments, the metal halide comprises at least one of sodium bromide, potassium bromide, calcium bromide, sodium chloride, potassium chloride, calcium chloride.
In some embodiments, the alkali metal hydroxide comprises sodium hydroxide and/or potassium hydroxide.
In some embodiments, the metal halide is first modified after high temperature atomization at 300-500 ℃.
In some embodiments, the alkali metal hydroxide is secondarily modified after low temperature atomization at 150-200 ℃.
The embodiment of the invention also provides a preparation method of the adsorbent for removing mercury and sulfur trioxide in flue gas, which is characterized by comprising the following steps:
(1) First modification: atomizing the metal halide at a high temperature of at least 300 ℃ and then modifying the activated carbon for the first time;
(2) And (3) secondary modification: atomizing the alkali metal hydroxide at a low temperature of 150-300 ℃ and then secondarily modifying the activated carbon.
The preparation method of the adsorbent for removing mercury and sulfur trioxide in flue gas provided by the embodiment of the invention has the advantages and technical effects that:
(1) The preparation method of the embodiment of the invention utilizes the high temperature of more than 300 ℃ to firmly attach the metal halide in the pores of the activated carbon when the activated carbon is activated for the first time to realize the stability of carrying halogen and the capability of efficiently adsorbing mercury, and then firmly attaches the alkali metal hydroxide on the surface of the activated carbon under the activation temperature condition of 150-300 ℃ to ensure that the activated carbon has high SO adsorption capability 3 The modified activated carbon has the capability of efficiently removing Hg and SO at the same time 3 Is not limited in terms of the ability to perform;
(2) According to the preparation method provided by the embodiment of the invention, the metal halide and the alkali metal hydroxide are directly attached to the surface of the activated carbon under the atomizing condition, so that the use amount of chemicals is greatly reduced, and meanwhile, the excessively high activation temperature is not required, the energy consumption is reduced, and the preparation cost is reduced;
(3) The preparation method provided by the embodiment of the invention has the advantages of simple production process and easiness in operation, and is beneficial to large-scale industrial production.
In some embodiments, the method of making comprises the steps of:
(1) First modification: injecting a metal halide solution with the concentration of 1-60% into a modification furnace with the temperature of at least 300 ℃ and keeping the metal halide solution with the activated carbon for 1 second-10 minutes, and carrying out first modification on the activated carbon after high-temperature atomization of the metal halide;
(2) And (3) secondary modification: injecting an alkali metal hydroxide solution with the concentration of 1-50% into a modification furnace with the temperature of 150-300 ℃, and keeping the alkali metal hydroxide solution with the activated carbon for 1 second to 10 minutes, wherein the alkali metal hydroxide is subjected to secondary modification after low-temperature atomization.
In some embodiments, the injection of the metal halide solution and the alkali metal hydroxide solution is by fluidic techniques.
In some embodiments, the modification furnace is a rotary activation furnace or a vertical activation furnace.
In some embodiments, the metal halide is injected in a high temperature zone of the modification furnace and the alkaline hydroxide is injected in a low temperature zone of the modification furnace.
Drawings
FIG. 1 is a schematic view showing the construction of a production apparatus employed in embodiments 1-2 of the present invention;
FIG. 2 shows the results of mercury removal efficiency test of the adsorbent for removing mercury, sulfur trioxide from flue gas according to example 1 of the present invention;
FIG. 3 shows the test results of sulfur trioxide removal efficiency of the sorbent for removing mercury, sulfur trioxide from flue gas of example 1 of the present invention;
FIG. 4 shows the results of mercury removal efficiency test of the sorbent for removing mercury, sulfur trioxide from flue gas according to example 2 of the present invention;
FIG. 5 shows the test results of sulfur trioxide removal efficiency of the sorbent for removing mercury, sulfur trioxide from flue gas of example 2 of the present invention;
reference numerals illustrate:
1-compressed air pipe, 2-alkali metal hydroxide solution storage tank, 3-metal halide solution storage tank, 4-ejector, 5-shower nozzle, 6-metering equipment, 7-low temperature zone, 8-high temperature zone, 9-modification furnace.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings. The embodiments described below by referring to the drawings are illustrative and intended to explain the present invention and should not be construed as limiting the invention.
The embodiment of the invention provides an adsorbent for removing mercury and sulfur trioxide in flue gas, which comprises the following components: the method comprises the steps of firstly atomizing the metal halide at a high temperature above 300 ℃ to perform first modification on the activated carbon, and then atomizing the alkali metal hydroxide at a low temperature between 150 and 300 ℃ to perform second modification on the activated carbon.
Working principle: embodiments of the inventionThe adsorbent is provided with the activated carbon carrier, the specific surface area of the adsorbent is increased, and Hg and SO are made to be 3 The contact area with the adsorbent is larger, and the adsorption and removal efficiency of the adsorbent is improved. In addition, the metal halide and the alkali metal hydroxide are simultaneously loaded on the inner and outer surfaces of the micropores of the activated carbon, SO that the adsorbent has the function of simultaneously removing Hg and SO in the flue gas 3 Is effective in (1). In addition, the adsorbent of the embodiment of the invention directly attaches the metal halide and the alkali metal hydroxide to the inner and outer surfaces of the active carbon pores by adopting the conditions of high-temperature atomization and low-temperature atomization in sequence, so that the usage amount of chemicals is greatly reduced, and meanwhile, the excessive activation temperature is not required, thereby saving energy and cost. The invention adopts the metal halide and the alkali metal hydroxide to be activated twice, and if the metal halide and the alkali metal hydroxide are directly mixed and activated once, a complex can be generated to influence the adsorption and removal performance of the adsorbent.
Preferably, in some embodiments, the activated carbon comprises at least one of coal activated carbon, wood activated carbon, coconut activated carbon. The activated carbon has loose and porous types and large specific surface area, and is more suitable for being used as an adsorbent carrier.
Preferably, in some embodiments, the particle size of the activated carbon is less than 100 mesh and more than 95% by weight, such that the activated carbon has a large specific surface area, more conducive to uniform loading of the metal halide and the alkali metal hydroxide, such that the same mass of the adsorbent is resistant to Hg and SO 3 The adsorption and removal effects of the catalyst are better.
Preferably, in some embodiments, the metal halide comprises at least one of sodium bromide, potassium bromide, calcium bromide, sodium chloride, potassium chloride, and calcium chloride, which are more resistant to adsorption and removal of Hg.
Preferably, in some embodiments, the alkali metal hydroxide comprises a readily water-soluble alkaline material such as sodium hydroxide and/or potassium hydroxide, such that the sorbent pair SO 3 The adsorption and removal effects of the catalyst are better.
Preferably, in some embodiments, the metal halide is first modified after high temperature atomization at 300-500 ℃. When the first modified atomization temperature is too low, insufficient atomization of the metal halide is easy to cause insufficient loading of the metal halide, and the adsorption and removal capacity of the adsorbent to Hg is weakened. When the first modification atomization temperature is too high, the modification effect of the activated carbon is not enhanced again, energy waste is caused, and unnecessary production cost is increased.
Preferably, in some embodiments, the alkali metal hydroxide is secondarily modified after low temperature atomization at 150-200 ℃. When the secondary modification atomization temperature is too low, insufficient atomization of the alkali metal hydroxide is likely to cause insufficient loading of the alkali metal hydroxide, and SO is weakened by the adsorbent 3 Is used for the adsorption and removal of the waste water. When the secondary modification atomization temperature is too high, the modification effect of the activated carbon is not enhanced again, energy waste is caused, and unnecessary production cost is increased.
The embodiment of the invention also provides a preparation method of the adsorbent for removing mercury and sulfur trioxide in flue gas, which is characterized by comprising the following steps:
(1) First modification: atomizing the metal halide at a high temperature of at least 300 ℃ and then modifying the activated carbon for the first time;
(2) And (3) secondary modification: atomizing the alkali metal hydroxide at a low temperature of 150-300 ℃ and then secondarily modifying the activated carbon.
Working principle: according to the preparation method provided by the embodiment of the invention, the metal halide solution and the alkali metal hydroxide solution are sequentially injected into the modification furnace under the activation temperature condition, atomized and evaporated under the activation temperature condition, and then mixed with the activated carbon, and uniformly stirred to prepare the modified activated carbon adsorbent. The preparation method comprises heating the activated carbon to above 300deg.C in a modifying furnace, and gradually expanding atomized metal halide into the gaps of the activated carbon under the action of steamThe carbon-based adsorbent can efficiently adsorb the Hg in the flue gas and has good thermal stability. Then spraying alkaline substances of alkali metal hydroxides when the temperature of the activated carbon is 150-300 ℃, and modifying the activated carbon again to ensure that the adsorbent has high-efficiency adsorption and removal of Hg and SO simultaneously 3 Ability to carry two contaminants.
In the related art, when the metal halide or the alkali metal hydroxide is independently supported on the activated carbon, a mixing and impregnating mode is generally adopted, so that the metal halide or the alkali metal hydroxide consumes a great amount in order to ensure sufficient impregnation, and wastes and environmental pollution are easily generated. In addition, the activation is generally carried out for a long time at the high temperature of 700-800 ℃, and the energy consumption is high.
The preparation method of the embodiment of the invention has no problems, and the metal halide can be firmly attached in the pores of the activated carbon only by utilizing the high temperature of the activated carbon above 300 ℃ during activation, so that the adsorbent realizes the capability of stably loading halogen and efficiently adsorbing Hg. Then the alkali metal hydroxide is adhered to the inner surface of the residual pores of the activated carbon by using the low temperature of 150-300 ℃ to ensure that the adsorbent has high adsorption SO 3 Capability. Therefore, the activation can be achieved without excessively high activation temperature. In addition, atomization enables the metal halide or the alkali metal hydroxide to be in sufficient contact with the activated carbon, and therefore, the consumption of the metal halide or the alkali metal hydroxide is also greatly reduced.
In some embodiments, the method of making comprises the steps of:
(1) First modification: injecting a metal halide solution with the concentration of 1-60% into a modification furnace with the temperature of at least 300 ℃ and keeping the metal halide solution with the activated carbon for 1 second-10 minutes, and carrying out first modification on the activated carbon after high-temperature atomization of the metal halide;
(2) And (3) secondary modification: injecting an alkali metal hydroxide solution with the concentration of 1-50% into a modification furnace with the temperature of 150-300 ℃, and keeping the alkali metal hydroxide solution with the activated carbon for 1 second to 10 minutes, wherein the alkali metal hydroxide is subjected to secondary modification after low-temperature atomization.
It can be seen that in some embodiments, the two activation times of the preparation process are also shorter, which is related to the two atomization processes, and the contact of the metal halide and alkali metal hydroxide with the activated carbon after atomization is more sufficient, so that the modification can be completed in a shorter time, and the production cycle is greatly shortened.
Preferably, in some embodiments, the injection of the metal halide solution and the alkali metal hydroxide solution is by a jet technique. For example, compressed air, nitrogen or CO may be used 2 The air is the power. The metal halide solution and the alkali metal hydroxide solution are sucked through a negative pressure port of the ejector after being sprayed by the high-speed power gas of the ejector through the metering device, and are injected into the modifying furnace along with the power gas, so that the modifying furnace is more favorable for full atomization.
In some embodiments, the modification furnace is a rotary activation furnace or a vertical activation furnace.
In some embodiments, the metal halide is injected in a high temperature zone of the modification furnace and the alkaline hydroxide is injected in a low temperature zone of the modification furnace. The partition injection materials are convenient for controlling the injection dosage and also convenient for automatically controlling the injection process.
The present invention will be described in detail with reference to the following examples and drawings.
Example 1
The preparation method of the adsorbent for removing mercury and sulfur trioxide in the flue gas specifically comprises the following steps:
(1) Firstly, adding activated carbon into a modifying furnace 9 (rotary activating furnace), heating the modifying furnace 9 to 400 ℃ at high temperature, injecting prepared calcium bromide solution with concentration of 48% into a high-temperature area 8 of the modifying furnace 9 for atomization, continuously stirring the activated carbon in the modifying furnace 9, activating for 5 minutes, fully contacting and mixing the activated carbon and gasified calcium bromide, and gradually entering the micropores of the activated carbon under the action of air flow and stirring.
In the step (1), the injection of the calcium bromide solution adopts a jet technology, as shown in fig. 1, compressed air is introduced into a compressed air pipe 1 as power gas, and the calcium bromide solution in a metal halide solution storage tank 3 is sucked through a negative pressure port of a jet device 4 after passing through a metering device 6 and is mixed with the power gas of the jet device, and is injected into a high temperature region 8 of a modification furnace 9 by a spray head 5.
(2) Along with the injection and stirring of the calcium bromide solution, the high-temperature activated carbon is gradually cooled to 250 ℃, the prepared sodium hydroxide solution with the concentration of 30% is injected into the low-temperature area 7 of the modification furnace 9, the modification furnace 9 is continuously stirred and activated for 5 minutes, the atomized sodium hydroxide and the activated carbon are fully contacted and mixed, and the sodium hydroxide is gradually adsorbed to the surface of the activated carbon. The adsorbent of example 1 was finally obtained, and the adsorbent comprises activated carbon and calcium bromide and sodium hydroxide supported on the activated carbon.
In the step (2), sodium hydroxide solution is injected by adopting a jet technology, as shown in fig. 1, compressed air is introduced into a compressed air pipe 1 as ejector power gas, sodium hydroxide solution in an alkali metal hydroxide solution storage tank 2 is sucked through a negative pressure port of an ejector 4 after passing through a metering device 6, and is mixed with ejector power gas, and is injected into a low-temperature region 7 of a modification furnace 9 by a nozzle 5.
Example 2
The preparation method of the adsorbent for removing mercury and sulfur trioxide in the flue gas specifically comprises the following steps:
(1) Firstly, adding activated carbon into a modification furnace 9 (rotary activation furnace), heating the modification furnace 9 to 320 ℃ at high temperature, injecting prepared potassium bromide solution with concentration of 30% into a high-temperature area 8 of the modification furnace 9, continuously stirring the modification furnace 9, activating for 5 minutes, fully contacting and mixing the activated carbon and the potassium bromide, and gradually entering the activated carbon micropores.
In the step (1), the injection of the potassium bromide solution adopts a jet technology, as shown in fig. 1, compressed air is introduced into a compressed air pipe 1 as power gas, the potassium bromide solution in a metal halide solution storage tank 3 is sucked through a negative pressure port of a jet device 4 after passing through a metering device 6, and is mixed with the power gas of the jet device, and is injected into a high temperature region 8 of a modification furnace 9 by a spray head 5.
(2) And cooling the high-temperature activated carbon to 150 ℃, injecting the prepared sodium hydroxide solution with the concentration of 50% into the low-temperature area 7 of the modifying furnace 9, continuously stirring the modifying furnace 9, activating for 5 minutes, fully contacting and mixing the atomized potassium hydroxide and the activated carbon, and gradually adsorbing the potassium hydroxide on the surface of the activated carbon. The adsorbent of example 1 was finally obtained, and the adsorbent includes activated carbon and potassium bromide and potassium hydroxide supported on the activated carbon.
In the step (2), the injection of the potassium hydroxide solution adopts a jet technology, as shown in fig. 1, compressed air is introduced into a compressed air pipe 1 as power gas, the potassium hydroxide solution in an alkali metal hydroxide solution storage tank 2 is sucked through a negative pressure port of an ejector 4 after passing through a metering device 6, and is mixed with ejector power gas, and is injected into a low-temperature area 7 of a modifying furnace 9 by a nozzle 5.
Adsorption removal of Hg and SO 3 Performance test:
a fixed bed was formed with 10g of the adsorbent of example 1, and 200℃flue gas containing 16.4ug/m was introduced 3 Mercury vapor and 50mg/m 3 SO of (2) 3 After 24-branch adsorption and removal, the Hg removal efficiency curve shown in figure 2 and the SO shown in figure 3 are obtained 3 An efficiency curve. As can be seen from fig. 2, the Hg removal efficiency can reach 98% or more at 7 minutes, and is reduced to 90% or less at 14 minutes, and is reduced to 37.8% at the last 24 minutes. As can be seen from FIG. 3, SO is removed 3 The maximum efficiency is 90.8 percent, and SO is within 9 minutes 3 The removal efficiency is above 80%, and SO is achieved in the last 24 minutes 3 The removal efficiency is reduced to 30.4%.
A fixed bed was formed with 10g of the adsorbent of example 2, and 250℃flue gas containing 16.4ug/m was introduced 3 Mercury vapor and 50mg/m 3 SO of (2) 3 After 24-seed adsorption and removal, the Hg removal efficiency curve shown in figure 4 and the SO shown in figure 5 are obtained 3 An efficiency curve. As can be seen from fig. 4, the Hg removal efficiency can reach 97% or more at 4 minutes, and is reduced to 90% or less at 11 minutes, and is reduced to 10.8% at the last 24 minutes. As can be seen from FIG. 5, SO is removed 3 The efficiency of the first 4 minutes is maintained above 98 percent, and SO is maintained within 10 minutes 3 The removal efficiency is above 90%, and SO is achieved in the last 24 minutes 3 The removal efficiency was reduced to 31.15%.
The adsorption removal experiments of examples 1-2 demonstrate that: according to the invention, under the condition of different temperatures of the modifying furnace, the metal halide and the alkali metal hydroxide are sequentially attached to the pores and the surface of the activated carbon, and the modified activated carbon can effectively remove Hg and SO in flue gas at the same time 3 . Further, from a comparison of example 1 and example 2, it can be seen that example 1 has a greater mercury removal capacity than that of example 2, and that example 2 removes SO 3 Is superior to example 1.
For purposes of this disclosure, the terms "one embodiment," "some embodiments," "example," "a particular example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.
While embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the invention, and that variations, modifications, alternatives and variations may be made to the above embodiments by one of ordinary skill in the art within the scope of the invention.

Claims (10)

1. An adsorbent for removing mercury and sulfur trioxide from flue gas, which is characterized by comprising: the method comprises the steps of firstly atomizing the metal halide at a high temperature above 300 ℃ to perform first modification on the activated carbon, and then atomizing the alkali metal hydroxide at a low temperature between 150 and 300 ℃ to perform second modification on the activated carbon.
2. The adsorbent for removing mercury and sulfur trioxide from flue gas according to claim 1, wherein the activated carbon comprises at least one of coal activated carbon, wood activated carbon and coconut activated carbon; preferably, the particle size of the activated carbon is less than 100 mesh and more than 95%.
3. The sorbent for removing mercury, sulfur trioxide from flue gas of claim 1, wherein the metal halides comprise at least one of sodium bromide, potassium bromide, calcium bromide, sodium chloride, potassium chloride, calcium chloride.
4. The sorbent for the removal of mercury, sulfur trioxide from flue gas according to claim 1, characterized in that the alkali metal hydroxide comprises sodium hydroxide and/or potassium hydroxide.
5. The adsorbent for removing mercury and sulfur trioxide from flue gas according to claim 1, characterized in that the metal halide is first modified after being atomized at a high temperature of 300-500 ℃.
6. The adsorbent for removing mercury and sulfur trioxide from flue gas according to claim 1, characterized in that the alkali metal hydroxide is secondarily modified after being atomized at a low temperature of 150-200 ℃.
7. The method for preparing the adsorbent for removing mercury and sulfur trioxide from flue gas according to any of claims 1-6, comprising the following steps:
(1) First modification: atomizing the metal halide at a high temperature of at least 300 ℃ and then modifying the activated carbon for the first time;
(2) And (3) secondary modification: atomizing the alkali metal hydroxide at a low temperature of 150-300 ℃ and then secondarily modifying the activated carbon.
8. The method for preparing the adsorbent for removing mercury and sulfur trioxide from flue gas according to claim 7, comprising the following steps:
(1) First modification: injecting a metal halide solution with the concentration of 1-60% into a modification furnace with the temperature of at least 300 ℃ and keeping the solution with the activated carbon for 1 second-10 minutes to carry out first modification on the activated carbon;
(2) And (3) secondary modification: an alkali metal hydroxide solution having a concentration of 1 to 50% is injected into a modification furnace having a temperature of 150 to 300 ℃ while maintaining the same with the activated carbon for 1 second to 10 minutes to secondarily modify the activated carbon.
9. The method for preparing the adsorbent for removing mercury and sulfur trioxide from flue gas according to claim 8, characterized in that the injection mode of the metal halide solution and the alkali metal hydroxide solution is jet technology.
10. The method for preparing the adsorbent for removing mercury and sulfur trioxide from flue gas according to claim 8, characterized in that the modifying furnace is a rotary type activating furnace or a vertical type activating furnace, the metal halide is injected in a high temperature zone of the modifying furnace, and the alkaline hydroxide is injected in a low temperature zone of the modifying furnace.
CN202310165679.9A 2023-02-24 2023-02-24 Adsorbent for removing mercury and sulfur trioxide in flue gas and preparation method thereof Pending CN116272864A (en)

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