CN107913680B - Preparation method of flue gas dearsenic adsorbent - Google Patents
Preparation method of flue gas dearsenic adsorbent Download PDFInfo
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- CN107913680B CN107913680B CN201711220671.9A CN201711220671A CN107913680B CN 107913680 B CN107913680 B CN 107913680B CN 201711220671 A CN201711220671 A CN 201711220671A CN 107913680 B CN107913680 B CN 107913680B
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- 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
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- 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
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- 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
- B01J20/10—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising silica or silicate
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- B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
- B01J20/22—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising organic material
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- B01J2220/00—Aspects relating to sorbent materials
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- 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
- B01J2220/4875—Sorbents characterised by the starting material used for their preparation the starting material being a waste, residue or of undefined composition
- B01J2220/4887—Residues, wastes, e.g. garbage, municipal or industrial sludges, compost, animal manure; fly-ashes
Abstract
The invention relates to a preparation method of a flue gas dearsenification adsorbent, and belongs to the technical field of flue gas dearsenification. The method comprises the following steps of mixing and uniformly mixing raw materials: uniformly mixing calcium oxide, metallurgical slag, zeolite and fly ash to prepare an adsorbent uniformly-mixed material; granulating in a second step: adding the uniformly mixed adsorbent material prepared in the step one into a cylindrical mixer, and preparing adsorbent particles after mixing and granulating; step three, pretreatment: and (3) heating the adsorbent particles prepared in the second step to 800-. The invention prolongs the retention time of the arsenic and the oxide thereof on the surface of the adsorbent, provides longer reaction time for the reaction of the adsorbent and the arsenic and the oxide thereof, promotes the reaction process of calcium oxide and arsenic, and improves the adsorption effect of the adsorbent on arsenic.
Description
Technical Field
The invention belongs to the technical field of flue gas pollution removal, and particularly relates to a preparation method of a flue gas dearsenic adsorbent.
Background
Large amount of SO in flue gas2，NOxAnd the like, because of large discharge amount and high concentration, people have long carried out relevant research work on the pollutants and have obtained remarkable achievement. With the increasing environmental protection pressure, researchers find that trace elements enriched in flue gas also cause serious damage to human bodies and the environment after entering the atmosphere, mainly because the trace elements haveHas precipitability and migratory property, is easy to be enriched on the surface of micron and submicron-grade particles, forms sol in the atmosphere and suspends in the sol for a long time, and enters the lung of a human body to cause serious respiratory diseases.
Wherein, arsenic is a global pollutant with great harm, has strong biological accumulation and carcinogenic teratogenicity, and is a great environmental problem threatening the health and ecological safety of human beings. Trace arsenic oxide in the atmosphere can poison people (the content of arsenic in the air is not more than 0.003mg/L), and the nervous system is damaged, and serious people even die. 60% to 75% of the total arsenic load in the atmosphere is caused by human activity factors. Wherein, the metal smelting occupies most of the metal smelting, and is about 35 to 65 percent. Therefore, research on arsenic removal of flue gas is urgently needed, and reasonable arsenic pollution control measures are explored.
Through searching, similar schemes are disclosed; for example: a device for removing arsenic and mercury in flue gas and a method for removing arsenic and mercury (application number: 201310750980.2, application date: 2013.12.31) comprise a denitration system, a dust remover, a magnetic separation machine, a mechanical screening machine and an injection system, wherein the denitration system is connected with a hearth, an outlet of the denitration system is connected with an inlet of the dust remover, the dust remover is connected with the magnetic separation machine and the mechanical screening machine, and the magnetic separation machine and the mechanical screening machine are connected with a pipeline in front of the inlet of the denitration system through the injection system. The device can effectively remove gaseous arsenic in the flue gas and can catalyze and oxidize elemental mercury in the flue gas. Although the technology can simultaneously reduce the emission of two pollutants of arsenic and mercury, no special adsorbent for arsenic removal exists, so that the emission reduction effect of arsenic needs to be further improved.
In addition, the integrated dedusting, desulfurizing and dearsenifying process for industrial fume includes absorbing SOx with inorganic sulfide while trapping dust particle in fume, reacting inorganic sulfide with mercury, arsenic and other toxic heavy metals in fume to produce insoluble sulfide salt, absorbing NOx with complexed ferrous iron, and regenerating absorbent with inorganic sulfide as reductant. Is favorable for removing toxic substances such as dust, SOx, NOx, mercury, arsenic and the like. Although the technology can simultaneously reduce emission of various pollutants, no special adsorbent for arsenic removal exists, so that the emission reduction effect of arsenic needs to be further improved.
Disclosure of Invention
1. Technical problem to be solved by the invention
The invention aims to overcome the problem that the flue gas dearsenification effect is limited because no special adsorbent for flue gas dearsenification exists in the prior art, and provides a preparation method of a flue gas dearsenification adsorbent.
2. Technical scheme
In order to achieve the purpose, the technical scheme provided by the invention is as follows:
the invention relates to a preparation method of a flue gas de-arsenic adsorbent, which comprises the steps of uniformly mixing calcium oxide, metallurgical furnace slag, zeolite and fly ash to prepare an adsorbent uniformly-mixed material, and adding the adsorbent uniformly-mixed material into a cylindrical mixer to prepare adsorbent particles.
Preferably, the specific preparation method comprises the following steps:
the method comprises the following steps: mixing the raw materials uniformly
Uniformly mixing calcium oxide, metallurgical slag, zeolite and fly ash to prepare an adsorbent uniformly-mixed material;
step two: granulating
Adding the uniformly mixed adsorbent material prepared in the step one into a cylindrical mixer, adding water into the mixer, and preparing adsorbent particles after mixing and granulating;
step three: pretreatment of
And (4) heating the adsorbent particles prepared in the step two to 800-900 ℃, and cooling to obtain the adsorbent.
Preferably, the step one: the method comprises the following specific steps of mixing and uniformly mixing the raw materials:
(1) preparation of mixture A: weighing calcium oxide, metallurgical slag and zeolite according to the parts by weight, sequentially adding the calcium oxide, the metallurgical slag and the zeolite into a stirrer, and uniformly mixing in the stirrer to obtain a mixture A;
(2) pretreating fly ash: adding the fly ash into a sodium hydroxide solution, wherein the concentration of the sodium hydroxide solution is 1.5mol/L, and drying to obtain modified fly ash;
(3) adding the fly ash into the mixture A, then adding the additive into the mixture, and uniformly mixing to obtain the uniform adsorbent material.
Preferably, step three: the pretreatment comprises the following specific steps: and (4) placing the adsorbent particles prepared in the step two into a microwave oven, carrying out microwave heating under the condition of nitrogen protection, heating to 800-900 ℃, preserving heat for 30min, and cooling to obtain the adsorbent.
Preferably, the addition amount of the fly ash is M4 ═ gamma (M1+ α M2-M3) - β/(1- α) M2, wherein M1 is the mass of calcium oxide, M2 is the mass of metallurgical slag, M3 is the mass of zeolite, gamma is 0.15-0.25, 1.5-2, α is the mass percentage content of CaO and MgO in the metallurgical slag, and β is the mass percentage content of Fe in the metallurgical slag2O3And MnO by mass percentage.
Preferably, the mass ratio of the calcium oxide to the metallurgical slag is 2.2 to 4.0.
Preferably, the additive also comprises additives, wherein the additives comprise blast furnace ash, chromium slag and mullite.
Preferably, the additive is added in an amount of 2-5% of the adsorbent.
Preferably, the composite material further comprises an accelerant, wherein the accelerant is an organic substance with the length-diameter ratio of more than 1000. .
3. Advantageous effects
Compared with the prior art, the technical scheme provided by the invention has the following beneficial effects:
(1) according to the preparation method of the flue gas de-arsenic adsorbent, the retention time of arsenic and oxides thereof on the surface of the adsorbent can be prolonged by the adsorbent, a longer reaction time is provided for the reaction of the adsorbent, the arsenic and the oxides thereof, and the alkali metal in the fly ash can promote the electricity of calcium oxide under the high-temperature conditionThe neutron shift and promote the arsenic atom to enter the vacancy or bridge of O or enter the top position of Ca, and the reaction process of calcium oxide and arsenic is promoted to form Ca-As complex: ca (AsO)2)2、Ca3(AsO4)2、Ca2As2O7And Ca3As2O8(ii) a Meanwhile, the coal ash and the converter slag act together to promote the decomposition of the iron oxide, and a large amount of metal in the coal ash promotes the formation of a large amount of reaction contact positions on the surface of the converter slag, promotes the reaction of arsenic and oxides thereof with the iron oxide or active calcium oxide of the converter slag, and improves the adsorption effect of the adsorbent on arsenic;
(2) according to the preparation method of the flue gas de-arsenic adsorbent, a large number of active ingredients in the converter slag can promote the combination of arsenic and oxides thereof with calcium oxide and the converter slag, and can directly react with arsenic, so that the adsorption effect of chemical adsorption is improved; the chemical adsorption fixes arsenic and oxides thereof, so that the arsenic content on the surface of the adsorbent is reduced, the physical adsorption is promoted, and the adsorption effect of the adsorbent on arsenic is improved.
Drawings
FIG. 1 is a structural diagram of an adsorption tower for arsenic removal from flue gas according to the present invention;
FIG. 2 is a flow chart of the preparation of the adsorbent for arsenic removal from flue gas according to the present invention.
The reference numerals in the schematic drawings illustrate:
110. an air inlet; 111. removing a water layer; 120. a flow-equalizing layer; 121. an air outlet; 122. a transverse plate; 123. a side plate; 130. a flow stabilizing layer; 140. an activated carbon adsorption layer; 150. an adsorbent bed; 160. an air outlet;
210. a resistive heating element; 220. a microwave heating unit; 230. the void is heated.
Detailed Description
The following detailed description of exemplary embodiments of the invention refers to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration exemplary embodiments in which the invention may be practiced. Although these exemplary embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, it should be understood that other embodiments may be realized and that various changes to the invention may be made without departing from the spirit and scope of the present invention. The following more detailed description of the embodiments of the invention is not intended to limit the scope of the invention, as claimed, but is presented for purposes of illustration only and not limitation to describe the features and characteristics of the invention, to set forth the best mode of carrying out the invention, and to sufficiently enable one skilled in the art to practice the invention. Accordingly, the scope of the invention is to be limited only by the following claims.
The detailed description and exemplary embodiments of the invention will be better understood when read in conjunction with the appended drawings, where the elements and features of the invention are identified by reference numerals.
Example 1
The invention relates to an adsorbent for flue gas dearsenification, which comprises calcium oxide, metallurgical slag, zeolite and fly ash, wherein the addition amount of the fly ash is M4 ═ gamma (M1+ α M2-M3) - β/(1- α) M2, wherein M1 is the mass of the calcium oxide, M2 is the mass of the metallurgical slag, M3 is the mass of the zeolite, gamma is 0.15-0.25 and is 1.5-2, wherein α is the mass percentage content of CaO and MgO in the metallurgical slag, and β is the mass percentage content of Fe in the metallurgical slag2O3And MnO by mass percentage. The mass ratio of calcium oxide to zeolite is 4 to 8, and 5 is used in this example.
The mass of the fly ash calculated by the following steps is that M4 ═ gamma (60+ α 20-12) - β/(1- α)20 ═ 8.14kg, wherein gamma is 0.2, 1.5, fly ash has large specific surface area, fly ash and zeolite have good adsorption effect on arsenic, so that the retention time of arsenic and oxides thereof on the surface of an adsorbent can be prolonged, and longer reaction time is provided for the reaction of the adsorbent, arsenic and oxides thereof, and the combined action of fly ash and calcium oxide can promote the electronic shift of calcium oxide by alkali metal in the fly ash under high temperature conditions, promote arsenic atoms to enter the vacant sites or bridge sites of O or top sites of Ca, promote the reaction process of calcium oxide and arsenic, and form Ca-As compound Ca (AsO-As compound)2)2、Ca3(AsO4)2、Ca2As2O7And Ca3As2O8The several calcium arsenate compounds can be mutually converted under certain conditions. Meanwhile, the coal ash and the converter slag act together to promote the decomposition of the iron oxide, and a large amount of metal in the coal ash promotes the formation of a large amount of reaction contact positions on the surface of the converter slag to promote the reaction of arsenic and oxides thereof with the iron oxide or active calcium oxide of the converter slag; in addition, a large number of active ingredients in the converter slag can promote the combination of arsenic and oxides thereof with calcium oxide and the converter slag, and can directly react with arsenic, so that the adsorption effect of chemical adsorption is improved; chemisorption fixes arsenic and its oxide for the arsenic content on adsorbent surface reduces, and then has promoted going on of physisorption, and both complement each other, thereby improved adsorption effect, and then improved the adsorption effect of adsorbent to arsenic, and probably take place following reaction:
4AsO(g)+O2(g)+2CaO＝2Ca(AsO2)2
4/3A8O(g)+O2(g)+2CaO＝2/3Ca3(AsO4)2
3AsO(g)+2.5O2(g)+2Fe3O4＝3FeAsO4
4/3AsO(g)+O2(g)+2MgO＝2/3Mg3(AsO4)2
4AsO(g)+O2(g)+2MgO＝2Mg(AsO2)2
As2O3(g)+3CaO+O2(g)＝Ca3(AsO4)2
2CaO+1/2As4O4(g)+O2＝Ca2As2O7(s)
on the other hand, the addition of too much fly ash can block the adsorption pore channels of the adsorbent, so that the adsorption effect is poor, and the transfer process from physical adsorption to chemical adsorption is influenced, therefore, the control of the composition in the adsorbent is particularly important in the process, and the invention is researched for a long timeM4 ═ gamma (M1+ α M2-M3) - β/(1- α) M2 is designed and each component is regulated, the metallurgical slag is converter slag, the percentage content of the converter slag is 43.5% of CaO, and the percentage content of SiO is regulated2：15.5％；Al2O3：3.8％；MgO：3.4％；Fe2O3: 5.2 percent; MnO: 2.4 percent; the balance being impurities.
The metallurgical slag is converter slag, and Fe in the converter slag2O3The mass percentage of (B) is more than 5%. The percentage content of the converter slag with the granularity of 0.074-5.0mm is more than 50 percent. The converter slag granularity is composed of the following components in percentage by mass: the granularity is less than or equal to 0.074 mm: 5%, 0.074-3.0 mm: 25%, 3.0-5.0 mm: 40 percent; 5.0-10.0 mm: 30 percent.
The fly ash of the embodiment is a fine particle obtained by quenching a fine particle in a vitreous state before a draught fan discharges coal-fired flue gas into the atmosphere, separating and collecting the fine particle through a dust remover, wherein the fly ash comprises the following components in percentage by mass: SiO 22：45.2％，Al2O3：28.6％，Fe2O3：8.7％，CaO：7.4％，MgO：3.6％，Na2O+K2O: 2.5 percent and the balance of impurities. The fly ash is modified by sodium hydroxide or potassium hydroxide, and the modifier is sodium hydroxide or potassium hydroxide; the method for treating the fly ash in the embodiment comprises the following steps: adding the fly ash into a sodium hydroxide solution, heating to 120 ℃ under a high pressure condition (the high pressure is 150-200 KPa) to react for 0.5-1h, and drying at 105 ℃ for 2h after the reaction is finished to obtain the modified fly ash.
The metallurgical slag is converter slag, and Fe in the converter slag2O3The mass percentage of (B) is more than 5%. The percentage content of the converter slag with the granularity of 0.074-5.0mm is more than 50 percent. The converter slag granularity is composed of the following components in percentage by mass: the granularity is less than or equal to 0.074 mm: 5%, 0.074-3.0 mm: 25%, 3.0-5.0 mm: 40 percent; 5.0-10.0 mm: 30 percent.
The fly ash of the embodiment is a fine particle obtained by quenching a fine particle in a vitreous state before a draught fan discharges coal-fired flue gas into the atmosphere, separating and collecting the fine particle through a dust remover, wherein the fly ash comprises the following components in percentage by mass: SiO 22：45.2％，Al2O3：28.6％，Fe2O3：8.7％，CaO：7.4％，MgO：3.6％，Na2O+K2O: 2.5 percent and the balance of impurities. The fly ash is modified by sodium hydroxide or potassium hydroxide, and the modifier is sodium hydroxide or potassium hydroxide; the method for treating the fly ash in the embodiment comprises the following steps: adding the fly ash into a sodium hydroxide solution, heating to 120 ℃ under a high pressure condition (the high pressure is 150-200 KPa) to react for 0.5-1h, and drying at 105 ℃ for 2h after the reaction is finished to obtain the modified fly ash.
As shown in fig. 2, the preparation method of the adsorbent of this example is:
the method comprises the following steps: mixing the raw materials uniformly
(1) Preparation of mixture A: weighing calcium oxide, metallurgical slag and zeolite according to the parts by weight, sequentially adding the calcium oxide, the metallurgical slag and the zeolite into a stirrer, and uniformly mixing in the stirrer to obtain a mixture A;
(2) pretreating fly ash: adding the fly ash into a sodium hydroxide solution, heating the solution to 120 ℃ under the condition of 150-200 KPa to react for 0.5-1h, and drying the solution for 2h at 105 ℃ after the reaction is finished to obtain modified fly ash, wherein the concentration of the sodium hydroxide solution is 1.5 mol/L;
(3) the mass of the fly ash is calculated according to a formula, wherein M4 is gamma (M1+ α M2-M3) - β/(1- α) M2, wherein M1 is the mass of calcium oxide, M2 is the mass of metallurgical slag, M3 is the mass of zeolite, gamma is 0.15-0.25, 1.5-2, α is the mass percentage content of CaO and MgO in the metallurgical slag, and β is the mass percentage content of Fe in the metallurgical slag2O3And MnO mass percentage content; adding the fly ash into the mixture A, and uniformly mixing to obtain a uniformly mixed adsorbent material;
step two: granulating
Adding the uniformly mixed adsorbent material prepared in the step one into a cylindrical mixer, adding water into the mixer, and preparing adsorbent particles after mixing and granulating;
step three: pretreatment of
Placing the adsorbent particles prepared in the second step into a microwave oven, carrying out microwave heating under the protection of nitrogen, heating to 800 ℃, and keeping the temperature for 30 min; the specific heating steps are as follows:
firstly, heating to 250 ℃ at a heating rate of 5 ℃/min, and keeping the temperature for 10 min;
secondly, heating to 800 ℃ at a heating rate of 10 ℃/min, and keeping the temperature for 30 min; obtaining an adsorbent after cooling; the adsorbent prepared by the method enables Ca-O, Si-O, Fe-O and Al-O on the surface of the adsorbent to be in a high-energy state, so that the adsorption performance of the adsorbent is improved. The method comprises the following steps that flue gas passes through an adsorbent at 400-900 ℃, the temperature selected in the embodiment is 800 ℃, the material layer thickness of the adsorbent is 500mm, and the flow rate of the flue gas is 0.2L/min; the content of arsenic in the flue gas at the inlet is 3 mg/L; the content of arsenic in the flue gas at the outlet is 0.58mg/L, and the emission reduction efficiency reaches 80.67%.
Example 2
The basic content of this embodiment is different from the embodiment in that: the additive comprises blast furnace ash, chromium slag and mullite; the composition comprises the following components in parts by mass: blast furnace ash: 60 percent, chromium slag: 20%, mullite: 20 percent. The additive is added in an external preparation mode, the addition amount of the additive is 1-2% of the adsorbent, and the addition amount of the additive is 1% in the embodiment, namely the addition amount of the additive is 1-2% of the sum of the mass of the calcium oxide, the metallurgical slag, the zeolite and the fly ash. Under the condition of high temperature, the metal element in the additive promotes electrons in the fly ash and the converter slag to shift under the high temperature condition, thereby promoting arsenic element in the flue gas to enter the vacancy and the bridge site of O in calcium oxide, improving the adsorption effect of the adsorbent on arsenic, and promoting the arsenic in the fly ash to enter the crystal lattice of vitreous aluminosilicate mineral by the metal in the additive to form AsO4 -3Is present in the form of an adsorbent; the mullite powder in the additive can be attached to the surface of converter slag or calcium oxide, and is promoted to be in a mullite lattice under the combined action of the converter slag, the calcium oxide and the mullite; in addition, the blast furnace dust and the chromium slag contain a large amount of alkali metal elements which can form NaAs with arsenic3O8，KAs3O8，K3AsO4The compounds of the same class are used as the raw materials,the performance of partial substances generated along with the reaction is not very stable, but the temporary adsorption effect of the adsorbent is improved by utilizing the intermediate products, so that the arsenic and the oxides thereof can be adsorbed on the surface of the adsorbent, the retention time of the arsenic and the oxides thereof on the surface of the adsorbent is increased, and a foundation is provided for the chemical adsorption of the adsorbent. The method comprises the following steps that flue gas passes through an adsorbent at 400-900 ℃, the temperature selected in the embodiment is 400 ℃, the material layer thickness of the adsorbent is 500mm, and the flow rate of the flue gas is 0.2L/min; the arsenic content in the flue gas at the inlet is 2 mg/L; the content of arsenic in the flue gas at the outlet is 0.35mg/L, and the emission reduction efficiency reaches 82.50%.
The specific preparation method of the adsorbent of the invention is as follows:
the method comprises the following steps: mixing the raw materials uniformly
(1) Preparation of mixture A: weighing calcium oxide, metallurgical slag and zeolite according to the parts by weight, sequentially adding the calcium oxide, the metallurgical slag and the zeolite into a stirrer, and uniformly mixing in the stirrer to obtain a mixture A;
(2) pretreating fly ash: adding the fly ash into a sodium hydroxide solution, heating the solution to 120 ℃ under the condition of 150-200 KPa to react for 0.5-1h, and drying the solution for 2h at 105 ℃ after the reaction is finished to obtain modified fly ash, wherein the concentration of the sodium hydroxide solution is 1.5 mol/L;
(3) weighing blast furnace ash, chromium slag and mullite in parts by weight, uniformly mixing, cleaning in a sodium hydroxide solution, and drying after cleaning to obtain an additive;
(4) the mass of the fly ash is calculated according to a formula, wherein M4 is gamma (M1+ α M2-M3) - β/(1- α) M2, wherein M1 is the mass of calcium oxide, M2 is the mass of metallurgical slag, M3 is the mass of zeolite, gamma is 0.15-0.25, 1.5-2, α is the mass percentage content of CaO and MgO in the metallurgical slag, and β is the mass percentage content of Fe in the metallurgical slag2O3And MnO mass percentage content; adding the fly ash into the mixture A, then adding the additive into the mixture, and uniformly mixing to obtain a uniformly mixed adsorbent material;
step two: granulating
Adding the uniformly mixed adsorbent material prepared in the step one into a cylindrical mixer, adding water into the mixer, and preparing adsorbent particles after mixing and granulating;
step three: pretreatment of
Placing the adsorbent particles prepared in the step two into a microwave oven, and carrying out microwave heating under the protection of nitrogen to 800-; the specific heating steps are as follows:
firstly, heating to 300 ℃ at a heating rate of 5 ℃/min, and preserving heat for 10 min;
secondly, heating to 900 ℃ at a heating rate of 10 ℃/min, and preserving heat for 30 min; and obtaining the adsorbent after cooling.
Example 3
The basic content of this example is the same as example 1, and further includes a promoter, and the promoter is an organic substance having an aspect ratio greater than 1000. The accelerant of the embodiment is plant fiber or animal hair fiber or plastic fiber, the accelerant is added in an external preparation mode, the addition amount of the accelerant is 0.05-0.2% of the adsorbent, and the addition amount of the accelerant is 0.1% in the embodiment, namely the addition amount of the accelerant is 0.05-0.2% of the sum of the mass of calcium oxide, metallurgical slag, zeolite and fly ash; the mixture of animal hair fibers and cotton fibers is adopted in the embodiment, and the mass ratio of the hair fibers to the cotton fibers is 2: 1; by adding hair fibers and cotton fibers into the adsorbent, larger mesopores can be distributed in the treated adsorbent, so that the specific surface area of the adsorbent is greatly increased, and the adsorption effect of the adsorbent can be improved; in addition, the pore passages are communicated with each other, so that the conversion from physical adsorption to chemical adsorption is promoted, the chemical adsorption effect is improved, and the continuous performance of the physical adsorption is promoted; thereby improving the adsorption effect of the adsorbent. The method comprises the following steps that flue gas passes through an adsorbent at 400-900 ℃, the temperature selected in the embodiment is 700 ℃, the material layer thickness of the adsorbent is 500mm, and the flow rate of the flue gas is 0.2L/min; the content of arsenic in the flue gas at the inlet is 4 mg/L; the content of arsenic in the flue gas at the outlet is 0.45mg/L, and the emission reduction efficiency reaches 88.75 percent.
Example 4
The basic content of this embodiment is different from the embodiment in that: the additive comprises blast furnace dust, chromium slag, mullite, sepiolite and carbon nitride, wherein the mass percentage of each component is as follows: blast furnace ash: 50 percent, chromium slag: 20 percent; mullite: 10%, sepiolite: 10 percent; carbon nitride: 10 percent of additive is added in an external preparation mode, and the addition amount of the additive is 1.5 percent of that of the adsorbent. The additive can improve the specific surface area of the adsorbent in the physical adsorption process, thereby improving the adsorption effect of the adsorbent; flue gas passes through an adsorbent at 400-900 ℃, the temperature selected in the embodiment is 600 ℃, the material layer thickness of the adsorbent is 500mm, and the flow rate of the flue gas is 0.2L/min; the arsenic content in the flue gas at the inlet is 2 mg/L; the content of arsenic in the flue gas at the outlet is 0.308mg/L, and the emission reduction efficiency reaches 84.60%.
Example 5
The basic content of this embodiment is different from the embodiment in that: the additive comprises blast furnace dust, chromium slag, mullite, sepiolite and iron scale, wherein the mass percentage of each component is as follows: blast furnace ash: 50 percent, chromium slag: 20 percent; mullite: 10%, sepiolite: 5 percent; iron scale: 15 percent of additive is added in an external preparation mode, and the addition amount of the additive is 1.8 percent of that of the adsorbent. The additive can improve the specific surface area of the adsorbent in the physical adsorption process, so that the adsorption effect of the adsorbent is improved, and the iron scale improves the chemical reaction process of adsorption and improves the adsorption effect; the method comprises the following steps that flue gas passes through an adsorbent at 400-900 ℃, the temperature selected in the embodiment is 700 ℃, the material layer thickness of the adsorbent is 600mm, and the flow rate of the flue gas is 0.2L/min; the arsenic content in the flue gas at the inlet is 2 mg/L; the content of arsenic in the flue gas at the outlet is 0.29mg/L, and the emission reduction efficiency reaches 85.50%.
Example 6
The basic content of this embodiment is different from the embodiment in that: the additive comprises blast furnace dust, chromium slag, mullite, sepiolite and attapulgite, wherein the mass percentage of each component is as follows: blast furnace ash: 50 percent, chromium slag: 20 percent; mullite: 10%, iron scale: 10 percent; attapulgite clay: 10 percent of additive is added in an external preparation mode, and the addition amount of the additive is 2 percent of that of the adsorbent. The attapulgite clay mineral containing water and rich in magnesium and aluminum silicate with a chain layer structure is subjected to a series of heating treatments, and the additive can improve the specific surface area in the physical adsorption process of the adsorbent, so that the adsorption effect of the adsorbent is improved, the iron scale improves the chemical reaction process of adsorption, and the adsorption effect is improved; flue gas passes through an adsorbent at 400-900 ℃, the temperature selected in the embodiment is 600 ℃, the material layer thickness of the adsorbent is 500mm, and the flow rate of the flue gas is 0.2L/min; the content of arsenic in the flue gas at the inlet is 3 mg/L; the content of arsenic in the flue gas at the outlet is 0.47mg/L, and the emission reduction efficiency reaches 84.33%.
Example 7
The basic content of this embodiment is different from the embodiment in that: the adsorbent also comprises sintered return ores, the addition amount of the sintered return ores is 5-10% of calcium oxide, the addition amount is 5% in the embodiment, the sintered return ores are sintered return ores with the granularity of 3-5mm, and the sintered return ores are ground into fine powder with the granularity of 1-3 mm; the raw material mixing method of the embodiment comprises the following steps:
(1) preparation of mixture A: weighing calcium oxide, metallurgical slag and zeolite according to the parts by weight, sequentially adding the calcium oxide, the metallurgical slag and the zeolite into a stirrer, and uniformly mixing in the stirrer to obtain a mixture A;
(2) pretreating fly ash: adding the fly ash into a sodium hydroxide solution, heating the solution to 120 ℃ under the condition of 150-200 KPa to react for 0.5-1h, and drying the solution for 2h at 105 ℃ after the reaction is finished to obtain modified fly ash, wherein the concentration of the sodium hydroxide solution is 1.5 mol/L;
(3) the mass of the fly ash is calculated according to a formula, wherein M4 is gamma (M1+ α M2-M3) - β/(1- α) M2, wherein M1 is the mass of calcium oxide, M2 is the mass of metallurgical slag, M3 is the mass of zeolite, gamma is 0.15-0.25, 1.5-2, α is the mass percentage content of CaO and MgO in the metallurgical slag, and β is the mass percentage content of Fe in the metallurgical slag2O3And MnO mass percentage content; and mixing the fly ash and the sintered return ores, adding the mixture of the fly ash and the sintered return ores into the mixture A, and uniformly mixing to prepare the uniform adsorbent material. The sintered return ores provide a large number of reaction pore passages for the adsorbent, and the adsorption surface area of the adsorbent is improved, so that the adsorption surface area of the adsorbent is improvedThe adsorption effect of the adsorbent; the method comprises the following steps that flue gas passes through an adsorbent at 400-900 ℃, the temperature selected in the embodiment is 500 ℃, the material layer thickness of the adsorbent is 600mm, and the flow rate of the flue gas is 0.2L/min; the content of arsenic in the flue gas at the inlet is 4 mg/L; the content of arsenic in the flue gas at the outlet is 0.72mg/L, and the emission reduction efficiency reaches 81.75 percent.
Example 8
In the adsorption tower for removing arsenic from flue gas of the embodiment, the tower bottom of the adsorption tower is provided with an air inlet 110, and the tower top is provided with an air outlet 160; the adsorption tower body is sequentially provided with a flow stabilizing layer 130, an active carbon adsorption layer 140 and an adsorbent material layer 150 from bottom to top; that is, the adsorbent material layer 150 is disposed on one side far away from the air inlet 110, the activated carbon adsorption layer 140 is closer to the air inlet 110 than the adsorbent material layer 150, the purified flue gas enters the adsorption tower from the air inlet 110, the flue gas firstly passes through the flow stabilizing layer 130 for flow stabilization, then passes through the activated carbon adsorption layer 140 for adsorption treatment, and finally, the adsorption effect of the adsorption tower is improved in the adsorbent material layer 150.
The flow stabilizing layer 130 is used for stabilizing the flue gas flow, so that the gas is uniformly distributed in the adsorption tower, the activated carbon adsorption layer 140 and the adsorbent material layer 150 can uniformly react with the flue gas, and activated carbon particles are paved in the activated carbon adsorption layer 140; the adsorbent layer 150 is paved with an adsorbent, and the adsorbent is the adsorbent for removing arsenic from the flue gas; the microwave heating component 220 is arranged at the upper part of the outer side of the adsorption tower body, and the resistance heating component 210 is arranged at the lower part of the outer side of the adsorption tower body; wherein the microwave heating element 220 is disposed corresponding to the upper portion of the adsorbent material layer 150, that is, the microwave heating element 220 is disposed on the outer circumference of the adsorbent material layer 150; the heating temperature of the microwave heating part 220 is 400-900 ℃.
The resistive heating member 210 is disposed to correspond to the lower portion of the adsorbent material layer 150 and the activated carbon adsorption layer 140. Namely, the lower part of the adsorbent material layer 150 and the outer circumference of the activated carbon adsorption layer 140 are provided with the resistance heating element 210, and the heating temperature of the resistance heating element 210 is 120-160 ℃; it is noted that the resistive heating element 210 spans across the activated carbon adsorption layer 140 and extends to the bottom of the adsorbent material layer 150; and be provided with heating gap 230 between microwave heating element 220 and the resistance heating element 210, heating gap 230 can make microwave heating element 220 and resistance heating element 210 between have interval and transition for the flue gas takes place the fluctuation of temperature when from activated carbon adsorption layer 140 to adsorbent bed 150, thereby promoted the fluctuation of air current flow direction, lay the foundation for improving the effect of dearsenifying. In addition, it is worth noting that a flow equalizing layer 120 is further arranged between the flow stabilizing layer 130 and the air inlet 110, a water removing layer 111 is arranged on the air inlet 110, and the water removing layer 111 is used for removing moisture in the flue gas; the flow equalizing layer 120 comprises a horizontal plate 122 and a side plate 123; the included angle between the transverse plate 122 and the side plate 123 is 120-150 degrees, the transverse plate 122 and the side plate 123 enclose a trapezoidal flow equalizing layer 120, and air outlet holes 121 are uniformly formed in the flow equalizing layer 120; after entering the adsorption tower from the gas inlet 110, the flue gas enters the tower body of the adsorption tower from the flow equalizing layer 120, passes through the flow stabilizing layer 130, and arsenic and oxides thereof in the flue gas of the adsorbent material layer 150 are adsorbed by the adsorbent; the heating temperature of the microwave heating part 220 of the present embodiment is 700 ℃; the bottom of the adsorbent material layer 150 and the outer circumference of the activated carbon adsorption layer 140 are provided with a resistance heating element 210, and the heating temperature of the resistance heating element 210 is 140 ℃. The adsorbent used is the adsorbent in example 1, and the arsenic content in the flue gas at the inlet is 4 mg/L; the content of arsenic in the flue gas at the outlet is 0.74mg/L, and the emission reduction efficiency reaches 81.50%. The multi-section heating adsorption is adopted, and the combination of the adsorbent and the physical adsorption is adopted, so that the adsorption effect of the adsorbent is improved.
The invention has been described in detail hereinabove with reference to specific exemplary embodiments thereof. It will, however, be understood that various modifications and changes may be made without departing from the scope of the invention as defined in the appended claims. The detailed description and drawings are to be regarded as illustrative rather than restrictive, and any such modifications and variations are intended to be included within the scope of the present invention as described herein. Furthermore, the background is intended to be illustrative of the state of the art as developed and the meaning of the present technology and is not intended to limit the scope of the invention or the application and field of application of the invention.
More specifically, although exemplary embodiments of the invention have been described herein, the invention is not limited to these embodiments, but includes any and all embodiments modified, omitted, combined, e.g., between various embodiments, adapted and/or substituted, as would be recognized by those skilled in the art from the foregoing detailed description. The limitations in the claims are to be interpreted broadly based the language employed in the claims and not limited to examples described in the foregoing detailed description or during the prosecution of the application, which examples are to be construed as non-exclusive. Any steps recited in any method or process claims may be executed in any order and are not limited to the order presented in the claims. The scope of the invention should, therefore, be determined only by the appended claims and their legal equivalents, rather than by the descriptions and examples given above.
Claims (6)
1. A preparation method of a flue gas dearsenic adsorbent is characterized by comprising the following steps: the preparation method comprises the following steps:
the method comprises the following steps: mixing the raw materials uniformly
Uniformly mixing calcium oxide, metallurgical slag, zeolite and fly ash to prepare an adsorbent uniformly-mixed material; wherein: the method comprises the following specific steps of mixing and uniformly mixing the raw materials:
(1) preparation of mixture A: weighing calcium oxide, metallurgical slag and zeolite according to the parts by weight, sequentially adding the calcium oxide, the metallurgical slag and the zeolite into a stirrer, and uniformly mixing in the stirrer to obtain a mixture A;
(2) pretreating fly ash: adding the fly ash into a sodium hydroxide solution, wherein the concentration of the sodium hydroxide solution is 1.5mol/L, and drying to obtain modified fly ash;
(3) adding the fly ash into the mixture A, then adding the additive into the mixture, and uniformly mixing to obtain a uniformly mixed adsorbent material;
the addition amount of the fly ash is M4 ═ gamma (M1+ α M2-M3) - β/(1- α) M2, wherein M1 is the mass of calcium oxide, M2 is the mass of metallurgical slag, M3 is the mass of zeolite, gamma is 0.15-0.25, 1.5-2, α is the mass percentage content of CaO and MgO in the metallurgical slag, and β is the weight percentage content of Fe in the metallurgical slag2O3And MnO in mass percentAn amount;
step two: granulating
Adding the uniformly mixed adsorbent material prepared in the step one into a cylindrical mixer, and preparing adsorbent particles after mixing and granulating;
step three: pretreatment of
And (4) heating the adsorbent particles prepared in the step two to 800-900 ℃, and cooling to obtain the adsorbent.
2. The preparation method of the flue gas de-arsenic adsorbent according to claim 1, wherein the preparation method comprises the following steps: step three: the pretreatment comprises the following specific steps: and (4) placing the adsorbent particles prepared in the step two into a microwave oven, carrying out microwave heating under the condition of nitrogen protection, heating to 800-900 ℃, preserving heat for 30min, and cooling to obtain the adsorbent.
3. The method for preparing the flue gas de-arsenic adsorbent according to claim 1 or 2, wherein the method comprises the following steps: the mass ratio of the calcium oxide to the metallurgical slag is 2.2 to 4.0.
4. The preparation method of the flue gas de-arsenic adsorbent according to claim 3, wherein the preparation method comprises the following steps: the additive also comprises an additive, wherein the additive comprises blast furnace ash, chromium slag and mullite.
5. The preparation method of the flue gas de-arsenic adsorbent according to claim 4, wherein the preparation method comprises the following steps: the addition amount of the additive is 2-5% of the mass of the adsorbent.
6. The preparation method of the flue gas de-arsenic adsorbent according to claim 4, wherein the preparation method comprises the following steps: the composite material also comprises an accelerant, wherein the accelerant is an organic matter with the length-diameter ratio larger than 1000.
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| CN101856607A (en) * | 2010-06-04 | 2010-10-13 | 重庆大学 | Flue gas demercuration adsorbent |
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Effective date of registration: 20211208 Address after: 225200 No. 3 Xilin Road, Xiannv Town, Jiangdu District, Yangzhou City, Jiangsu Province Patentee after: YANGZHOU XINXIN METALLURGICAL EQUIPMENT MANUFACTURING CO.,LTD. Address before: 243002 59 Hudong Middle Road, Huashan District, Ma'anshan, Anhui Patentee before: ANHUI University OF TECHNOLOGY |