CN113649037A - Catalyst suitable for low-temperature catalytic oxidation of mercury in oxygen-rich combustion flue gas and preparation method thereof - Google Patents

Catalyst suitable for low-temperature catalytic oxidation of mercury in oxygen-rich combustion flue gas and preparation method thereof Download PDF

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CN113649037A
CN113649037A CN202111009966.8A CN202111009966A CN113649037A CN 113649037 A CN113649037 A CN 113649037A CN 202111009966 A CN202111009966 A CN 202111009966A CN 113649037 A CN113649037 A CN 113649037A
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catalyst
flue gas
mercury
mixture
oxygen
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赵波
胡子沁
韩军
单威威
秦林波
陈旺生
田磊
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Wuhan University of Science and Engineering WUSE
Wuhan University of Science and Technology WHUST
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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
    • B01J27/00—Catalysts comprising the elements or compounds of halogens, sulfur, selenium, tellurium, phosphorus or nitrogen; Catalysts comprising carbon compounds
    • B01J27/20—Carbon compounds
    • B01J27/22—Carbides
    • 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
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
    • B01D53/86—Catalytic processes
    • B01D53/8637—Simultaneously removing sulfur oxides and nitrogen oxides
    • 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
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
    • B01D53/86—Catalytic processes
    • B01D53/8643—Removing mixtures of carbon monoxide or hydrocarbons and nitrogen oxides
    • 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
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
    • B01D53/86—Catalytic processes
    • B01D53/8665—Removing heavy metals or compounds thereof, e.g. mercury

Abstract

A catalyst suitable for low-temperature catalytic oxidation of oxygen-rich combustion flue gas mercury comprises 5-10% by mass of manganese dioxide, 5-8% by mass of molybdenum trioxide, 2-10% by mass of tungsten trioxide and the balance of multi-walled carbon nanotubes. The preparation method of the catalyst comprises the following steps: carrying out acidolysis on the multi-walled carbon nano-tube in a nitric acid solution to enhance the hydrophilicity, and mixing and oscillating the multi-walled carbon nano-tube with a citric acid solution; dissolving molybdenum trioxide in ammonia water and ammonium tungstate in water, mixing with manganese nitrate solution, and adding into suspension containing multi-walled carbon nanotubesIn the process, shaking and drying are carried out to obtain a solid; calcining and grinding the solid in inert atmosphere to obtain the catalyst. The catalyst suitable for low-temperature catalytic oxidation of mercury in oxygen-enriched combustion flue gas provided by the invention has strong sulfur resistance, and can effectively utilize high-concentration CO in the oxygen-enriched combustion flue gas2The catalytic oxidation activity of the catalyst is enhanced, the optimal oxidation efficiency of mercury in experimental atmosphere reaches 94%, and the optimal activity temperature is as low as 100 ℃.

Description

Catalyst suitable for low-temperature catalytic oxidation of mercury in oxygen-rich combustion flue gas and preparation method thereof
Technical Field
The invention relates to a catalyst suitable for low-temperature catalytic oxidation of oxygen-rich combustion flue gas mercury and a preparation method thereof, belonging to the technical field of purification of atmospheric pollution.
Background
CO of coal-fired power plant2Emissions are an important factor in global warming. In order to control the average temperature rise of the earth's surface to between 2-2.4 ℃ before 2050 years, CO2The emission must be reduced by 50-85%. CO 22Capture and Storage (CCS) to reduce CO in coal combustion processes2Efficient method of emissions, and oxygen-enriched combustion (O)2/CO2Combustion) is one of the most technically feasible and economically competitive CCS processes at present. Burning with air (O)2/N2Combustion) due to the substitution of O by pure oxygen/recycled flue gas2/N2The coal powder is combusted, and the components of the oxygen-enriched combustion flue gas are greatly changed: CO 22The concentration reaches more than 95 percent; h2O、SO2、SO3And Hg concentration were both multiplied. In the oxygen-enriched combustion flue gas, except particulate matters and SO2And NOxExcept for the removal of the conventional pollutants, the mercury in the flue gas can be mixed with aluminum CO2The amalgam reaction in the compressor to produce aluminium amalgam which embrittles the compressor and causes serious safety accident, so that mercury enters into CO2The compression unit must be removed from the flue gas before it can be used.
During coal combustion, mercury is primarily elemental mercury (Hg)0) Granular mercury (Hg)p) And divalent mercury (Hg)2+) Three shapesThe formula is present in coal-fired flue gas. Among them, divalent mercury (Hg)2+) Is easily removed by a wet desulphurization unit (WFGD) because of being easily soluble in water, and has granular mercury (Hg)p) Can be easily removed by electrostatic dust collector or bag-type dust collector with particulate matter, and elemental mercury (Hg) can be easily removed0) Due to its strong volatility and water insolubility, it is difficult to remove with current flue gas purification device. Research results have shown that Hg is removed using an oxidant or catalyst0Conversion to Hg2+Hg can be removed by wet desulfurizing device (WFGD)0The effective control of (2). O is2/N230-80% Hg in combustion0Can be catalyzed and oxidized by a Selective Catalytic Reduction (SCR) denitration system configured by a power plant, so that the Hg/NO removed by the SCR catalyst is converted into O2/N2The research under combustion is hot. O is2/CO2In combustion, due to NOxThe removal requirement still needs to be configured with an SCR system, if a high-temperature SCR system arrangement mode in an air combustion power plant is adopted, N formed in flue gas through an SCR process2Is carried into the high-temperature hearth by the circulating flue gas and can be oxidized into NO again in the high-temperature combustion processxPartially weakening the function of the SCR system and configuring the SCR system at the oxygen-enriched combustion flue gas circulation point (temperature)<The arrangement mode after 150 ℃) can effectively avoid the problems, and the arrangement mode has the advantages of reduced smoke temperature, reduced volume, reduced catalyst consumption and enhanced economy. Therefore, the research on the synergistic removal of Hg/NO by the oxygen-enriched combustion low-temperature SCR catalyst has important practical significance, and the development of the low-temperature catalyst suitable for the oxygen-enriched combustion flue gas components is key.
It has been shown that MnOxIs a low-temperature catalyst active component with good performance, and Mn is contained in the temperature range of 100 ℃ and 250 DEG C4+Can be removed from Hg adsorbed on the surface of the catalyst0Acquire electrons, are reduced to Mn3+Or Mn2+，Hg0Will be oxidized to Hg2+. O in flue gas2Then can be adsorbed on the active sites on the surface of the catalyst to form lattice oxygen, and then Mn is added3+Or Mn2+By oxidation to Mn4+To achieve low-temperature high-efficiency catalytic oxidation of mercury, but poor MnOxThe structure can inhibit catalysisActivity of the agent by supporting MnO on a porous supportxCan effectively improve MnOxOxidation performance of (2).
Among many catalyst support materials, a catalyst prepared by supporting a metal oxide on the surface of a carbon-based material has attracted attention because of having both high adsorptivity of the carbon-based material and oxidizability of the metal oxide. The Carbon Nano Tube (CNT) is a novel one-dimensional nano carbon-based material, the internal graphite-like lamellar structure of the CNT can provide a large number of adsorption sites, and the BET specific surface area can reach up to 2000m2The CNT has high graphitization degree and strong electron transfer capability, and can strengthen the catalytic reaction process through a rapid electron transfer mechanism. The research result shows that MnO is reducedxThe synthesized Mn/CNT loaded on the surface of the CNT reaches the mercury oxidation efficiency of more than 90 percent at 200 ℃. However, the sulfur resistance of Mn/CNT is poor, when 500ppm SO is present in flue gas2When the mercury is oxidized, the mercury oxidation efficiency is reduced to 30%. In oxyfuel combustion, SO is in the flue gas due to flue gas recirculation2The concentration is multiplied.
Disclosure of Invention
The invention aims to provide a low-temperature catalyst with excellent performance for catalytic oxidation of elemental mercury in oxygen-enriched combustion flue gas by combining the characteristics of the oxygen-enriched combustion flue gas, and fills the blank of a mercury oxidation catalyst in oxygen-enriched combustion. The catalyst has the advantages that the active ingredient of the catalyst is manganese dioxide, the auxiliary agent ingredients are molybdenum trioxide and tungsten trioxide, the carrier ingredient is the multi-walled carbon nano tube, the ratio of the active ingredient to the auxiliary agent in the catalyst is adjusted, so that the catalyst has higher mercury catalytic oxidation efficiency at low temperature, and the sulfur resistance of the catalyst can be effectively enhanced.
The invention adopts the technical idea that the auxiliary agent Mo can improve the dispersibility of the active component, and Mo6+To SO2Has higher affinity than Mn4+And Mo is6+Can strengthen O2Effectively block SO for the oxidation of active ingredients of low-valence metals2And the active component, thereby improving the sulfur resistance of the Mn/CNT catalyst. In addition, W is added into the catalyst to effectively utilize CO in the oxygen-enriched combustion flue gas2Higher content of the active ingredient, based on WO3The prepared nanotube hasA large number of surface W-O vacancy structures can form stable electron transport channels, and CO can be transported at normal temperature2Converted into active groups such as C-O and the like, and effectively enhances the reaction activity of the catalyst. Based on the method, the auxiliary agents Mo and W are added into Mn/CNT to synthesize the catalyst suitable for low-temperature catalytic oxidation of the mercury in the oxygen-enriched combustion flue gas.
The technical scheme adopted for realizing the technical purpose of the invention is as follows: a catalyst suitable for low-temperature catalytic oxidation of mercury in oxygen-rich combustion flue gas is characterized in that: the catalyst comprises 5-10% of manganese dioxide, 5-8% of molybdenum trioxide and 2-10% of tungsten trioxide by mass percentage, and the balance of the catalyst is a multi-walled carbon nanotube.
Further, the catalyst is ground into 80-325 meshes.
A preparation method of a catalyst suitable for low-temperature catalytic oxidation of mercury in oxygen-rich combustion flue gas comprises the following steps:
(1) mixing 80-88 parts by weight of multi-walled carbon nanotubes with deionized water 20 times of the mass of the multi-walled carbon nanotubes, and stirring uniformly at room temperature to obtain a mixture AI;
(2) taking 10 wt% HNO according to 1/5 volume of deionized water in the step (1)3Adding the mixture into the mixture AI, and uniformly stirring at room temperature to obtain a mixture AII;
(3) adding citric acid with the concentration of 10 wt% into the mixture AII according to the 1/10 volume of the deionized water in the step (1), and uniformly stirring at room temperature to obtain a mixture AIII;
(4) weighing 10.29-20.58 parts by weight of Mn (NO)3)2Dissolving in deionized water to obtain a solution BI; weighing 5-8 parts by weight of molybdenum trioxide, and dissolving the molybdenum trioxide in the HNO in the step (2)3Obtaining solution BII in ammonia water with the same volume; weighing 2.187-10.936 parts by weight of ammonium tungstate, and dissolving in 1/5 parts by volume of deionized water in the step (1) to obtain a solution BIII;
(5) introducing the solution BI, the BII and the BIII obtained in the step (4) into the mixture AIII in sequence, then adding concentrated nitric acid to adjust the pH value to 1.0, shaking for 24h at 50 ℃, then heating to 80 ℃ and drying for 48h at 80 ℃ to obtain solid A;
(6) and (5) placing the solid A obtained in the step (5) in a muffle furnace, heating to 400 ℃, calcining for 5 hours in an inert atmosphere, and grinding to obtain the catalyst.
Preferably, in the step (6), the temperature of the solid A is increased at a temperature increase rate of 10 ℃/min.
At present, the catalytic oxidation of mercury in oxygen-enriched combustion flue gas still focuses on the high-temperature vanadium-based catalyst which is applied in the traditional air combustion, and the high-temperature vanadium-based catalyst is not applicable due to the flue gas recirculation in the oxygen-enriched combustion, so that a low-temperature catalyst which can be configured behind an electrostatic dust collector is needed, but reports on the mercury oxidation effect and mechanism research of the low-temperature catalyst in the oxygen-enriched combustion flue gas are few.
The applicant of the present invention found through research that due to the nanotube structure and high specific surface area of the CNT, the specific surface area of the manganese-based catalyst prepared by using the CNT as the carrier is higher than 170m2The concentration is far higher than that of the traditional catalyst by 50-70 m2(g) addition of MoO to Mn/CNT3And WO3Then, a large amount of MnO is made to exist on the surface of the catalyst2，MoO3And WO3It is explained that the active component on the surface of the catalyst synthesized by the method exists in a high valence state, and has strong oxidizing ability. In addition, MoO3Is added to prevent SO2Adsorbing on the surface of the catalyst to prevent SO2Further to SO3The sulfur resistance of the catalyst is enhanced. And WO3The addition of (2) obviously enhances the catalyst in high concentration CO2Catalytic activity in the flue gas present.
The applicant of the invention researches the catalytic oxidation effect of the catalyst on the elemental mercury in the oxygen-enriched combustion flue gas at different temperatures and different addition ratios of the active ingredients through a large number of experiments. The experimental result shows that when the content of manganese dioxide in the catalyst is 5-10%, the content of molybdenum trioxide is 5-8%, and the content of tungsten trioxide is 2-10%, the catalyst is in SO2Optimum mercury oxidation efficiency in the presence of oxygen-enriched combustion flue gasThe content of the mercury reaches 94%, so that the catalyst suitable for catalytic oxidation of elemental mercury in the oxygen-enriched combustion flue gas under the low-temperature condition can be prepared under the reasonable active component proportion, and the blank of development of the low-temperature mercury oxidation catalyst in the oxygen-enriched combustion flue gas is effectively filled.
Drawings
FIG. 1 is an XPS analysis of catalyst samples with different W addition levels (a) Mn 2 p;
FIG. 2 is an XPS analysis of catalyst samples with different W addition levels (b) Mo 3 d;
FIG. 3 is an XPS analysis of catalyst samples with different W addition levels (c) W4 f;
fig. 4 is an XRD analysis pattern of the catalyst prepared by the present invention.
Detailed Description
The present invention will be described in further detail with reference to specific examples, but the embodiments of the present invention are not limited thereto, and may be carried out with reference to conventional techniques for process parameters not particularly noted. The multi-walled carbon nanotubes used in the embodiments of the present invention are all purchased from Shenzhen Heizheng technology Limited (No. CAS 308068-56-6).
Example 1 Catalyst (CM)5Mo5W2) Preparation of
Comprises the following steps:
(1) mixing 88 parts by weight of multi-walled carbon nanotubes with deionized water 20 times the mass of the multi-walled carbon nanotubes, and stirring at 30 ℃ for 1 hour to obtain a mixture AI;
(2) taking 10 wt% HNO according to 1/5 volume of deionized water in the step (1)3Adding into mixture AI, and stirring at 30 deg.C for 0.5h to obtain mixture AII;
HNO in this step3Has the main functions of opening the chain structure of the hydrophobic multi-walled carbon nano-tube, facilitating the impregnation of active ingredients, using concentrated nitric acid instead of using dilute HNO with other concentrations3Will not affect the effect
(3) Adding citric acid with the concentration of 10 wt% into the mixture AII according to the 1/10 volume of the deionized water in the step (1), and stirring at 30 ℃ for 0.5h to obtain a mixture AIII;
the citric acid in the step has the function of enhancing the dispersibility of the active substances added subsequently in the solution, and the citric acid with other concentrations cannot influence the effect.
(4) Mn (NO) was weighed out at a concentration of 50 wt%3)220.58 parts by weight of solution BI, weighing 5 parts by weight of molybdenum trioxide, and dissolving the molybdenum trioxide in the HNO in the step (2)3Adding the solution into ammonia water with the same volume to obtain a solution BII; weighing 2.187 parts by weight of ammonium tungstate, and dissolving in 1/5 parts by volume of deionized water in the step (1) to obtain a solution BIII;
in this step, molybdenum trioxide is soluble in ammonia water and strong alkali, and ammonia water is selected to dissolve molybdenum trioxide so as not to introduce other impurity components difficult to treat, and from the XPS analysis results of fig. 1 to 3, HNO is observed3Citric acid, Mn (NO)3)2Ammonium molybdate, ammonium tungstate and carbon nano tube, and changes the form and proportion of active components Mn and Mo existing on the surface of the catalyst, such as higher Mn4+And Mo6+This variation may cause the catalyst to favor the oxidation of mercury in the oxygen-rich flue gas.
(5) Introducing the solution BI, the BII and the BIII obtained in the step (4) into the mixture AIII in sequence, then adding concentrated nitric acid to adjust the pH value to 1.0, shaking for 24h at 50 ℃, then heating to 80 ℃ and drying for 48h at 80 ℃ to obtain solid A;
the catalyst with better performance can be synthesized only when the acidity is stronger, namely the pH value is lower, and in order to remove impurity components in the calcining process, HNO is added3The pH is adjusted.
(6) And (3) placing the solid A obtained in the step (5) in a muffle furnace, heating to 400 ℃ at the heating rate of 10 ℃/min, calcining for 5h in an inert atmosphere, and grinding to obtain the catalyst.
The catalyst comprises 5 parts by weight of manganese dioxide, 5 parts by weight of molybdenum trioxide, 2 parts by weight of tungsten trioxide and the balance of multi-walled carbon nanotubes.
Example 2 Catalyst (CM)5Mo5W6) Preparation of
Comprises the following steps:
(1) mixing 84 parts by weight of multi-walled carbon nanotubes with deionized water 20 times of the mass of the multi-walled carbon nanotubes, and stirring at 30 ℃ for 1 hour to obtain a mixture AI;
steps (2) to (3) are the same as in example 1;
(4) mn (NO) was weighed out at a concentration of 50 wt%3)220.58 parts by weight of solution BI, weighing 5 parts by weight of molybdenum trioxide, and dissolving the molybdenum trioxide in the HNO in the step (2)3Adding the solution into ammonia water with the same volume to obtain a solution BII; weighing 6.562 parts by weight of ammonium tungstate, and dissolving in 1/5 parts by volume of deionized water in the step (1) to obtain a solution BIII;
(5) introducing the solution BI, the BII and the BIII obtained in the step (4) into the mixture AIII in sequence, then adding concentrated nitric acid to adjust the pH value to 1.0, shaking for 24 hours at the temperature of 50 ℃, then heating to 80 ℃ and drying for 48 hours at the temperature of 80 ℃ to obtain solid A;
(6) and (3) placing the solid A obtained in the step (5) in a muffle furnace, heating to 400 ℃ at the heating rate of 10 ℃/min, calcining for 5h in an inert atmosphere, and grinding to obtain the catalyst.
Example 3 Catalyst (CM)5Mo5W10) Preparation of
Comprises the following steps:
(1) mixing 80 parts by weight of multi-walled carbon nanotubes with deionized water 20 times the mass of the multi-walled carbon nanotubes, and stirring at 30 ℃ for 1 hour to obtain a mixture AI;
steps (2) to (3) are the same as in example 1;
(4) mn (NO) was weighed out at a concentration of 50 wt%3)220.58 parts by weight of solution BI, weighing 5 parts by weight of molybdenum trioxide, and dissolving the molybdenum trioxide in the HNO in the step (2)3Adding the solution into ammonia water with the same volume to obtain a solution BII; weighing 10.936 parts by weight of ammonium tungstate, and dissolving in 1/5 parts by volume of deionized water in the step (1) to obtain a solution BIII;
(5) introducing the solution BI, the BII and the BIII obtained in the step (4) into the mixture AIII in sequence, then adding concentrated nitric acid to adjust the pH value to 1.0, shaking for 24 hours at the temperature of 50 ℃, then heating to 80 ℃ and drying for 48 hours at the temperature of 80 ℃ to obtain solid A;
(6) and (3) placing the solid A obtained in the step (5) in a muffle furnace, heating to 400 ℃ at the heating rate of 10 ℃/min, calcining for 5h in an inert atmosphere, and grinding to obtain the catalyst.
Comparative example 1 Catalyst (CM)5) Preparation of
Comprises the following steps:
(1) mixing 95 parts by weight of multi-walled carbon nanotubes with deionized water 20 times the mass of the multi-walled carbon nanotubes, and stirring at 30 ℃ for 1 hour to obtain a mixture AI;
steps (2) to (3) are the same as in example 1;
(4) mn (NO) was weighed out at a concentration of 50 wt%3)220.58 parts by weight of solution BI;
(5) introducing the solution BI obtained in the step (4) into the mixture AIII, adding concentrated nitric acid to adjust the pH value to 1.0, oscillating for 24 hours at 50 ℃, heating to 80 ℃, and drying for 48 hours at 80 ℃ to obtain solid A;
(6) and (3) placing the solid A obtained in the step (5) in a muffle furnace, heating to 400 ℃ at the heating rate of 10 ℃/min, calcining for 5h in an inert atmosphere, and grinding to obtain the catalyst.
Comparative example 2 Catalyst (CM)5Mo5) Preparation of
Comprises the following steps:
(1) mixing 90 parts by weight of multi-walled carbon nanotubes with deionized water 20 times the mass of the multi-walled carbon nanotubes, and stirring at 30 ℃ for 1 hour to obtain a mixture AI;
steps (2) to (3) are the same as in example 1;
(4) mn (NO) was weighed out at a concentration of 50 wt%3)220.58 parts by weight of solution BI; weighing 5 parts by weight of molybdenum trioxide, and dissolving the molybdenum trioxide in the HNO in the step (2)3Obtaining solution BII in ammonia water with the same volume;
(5) introducing the solution BI and the BII obtained in the step (4) into the mixture AIII in sequence, adding concentrated nitric acid to adjust the pH value to 1.0, shaking for 24 hours at 50 ℃, heating to 80 ℃, and drying for 48 hours at 80 ℃ to obtain solid A;
(6) and (3) placing the solid A obtained in the step (5) in a muffle furnace, heating to 400 ℃ at the heating rate of 10 ℃/min, calcining for 5h in an inert atmosphere, and grinding to obtain the catalyst.
Catalyst Activity test experiment
The activity of the six catalysts prepared in the three examples of the present invention and the two comparative examples was tested on a fixed bed reactor, respectively, and the mercury oxidation rate was the test item. The test conditions were: the simulated flue gas flow is 0.9Nm3H; the simulated smoke comprises the following components in volume concentration: 0.04% NO, 0.04% NH3，6％O2，8％H2O，0.08％SO20.002% HCl, and 55. mu.g/Nm3 Hg0The balance being CO2(ii) a The reaction temperature is 50 ℃, 100 ℃ and 150 ℃; the amount of catalyst used in a single test was 0.05 g. The flue gas treated by the catalyst is subjected to continuous online testing of Hg in the flue gas by adopting an RA915M mercury-measuring instrument manufactured by Russian Lumex company. The mass concentration is 0-200 mu g/m3. The precision is 0.1 mu g/m3. Catalyst for oxidation of Hg0Capacity of Hg by0An oxidation rate characterization, wherein: eta is Hg0The oxidation rate; c0Is Hg at the outlet of the reactor0Mass concentration,. mu.g/m3；C1Is Hg at the reactor inlet0Mass concentration,. mu.g/m3. The detection principle is Hg0Selective absorption of 253.7nm uv. The test results are shown in the following table:
Figure BDA0003238552170000111
when MnO is present2、MoO3When the weight percentage of (B) is less than 5%, the demercuration effect is extremely poor. Increase MnO2、MoO3The weight percentage of (b) can enhance the mercury removal effect, but also increases the cost.
As can be seen from the above table: in the presence of 5% MnO2And 5% MoO36 to 10 percent of WO is added into the catalyst3Then, the oxidation performance of elemental mercury in the oxygen-enriched combustion flue gas of the catalyst at 100 ℃ can be obviously improved, and the optimal mercury oxidation effectThe rate reaches 94 percent.
The characteristic of catalytic oxidation of elemental mercury in oxygen-enriched combustion flue gas by the modified carbon nano tube introduces that the catalyst can resist sulfur by adding Mo, but CO2Too high a concentration carbonates the active manganese component and therefore CO2Too high a volume fraction strongly inhibits the oxidation of mercury by the catalyst; the experimental temperature of the catalytic reaction in this document is 150 ℃ and in the present invention the optimum activity temperature of the catalyst after addition of W is further reduced to 100 ℃ WO3The nanotube structure can promote CO2Conversion to C-O-C structure, CO at 100 ℃2Should be preferentially in active WO3Internal conversion, thereby avoiding carbonation of the manganese component.
Because of the nano-pipeline structure and high specific surface area of the CNT, the specific surface area of the manganese-based catalyst prepared by taking the CNT as the carrier is higher than 170m2The concentration is far higher than that of the traditional catalyst by 50-70 m2In terms of/g, see the results in Table 1.
TABLE 1 BET specific surface area, pore volume and pore size distribution of the catalysts
Figure BDA0003238552170000121
As shown in FIGS. 1 to 4, MoO was added to Mn/CNT3And WO3Then, it can be clearly seen that a large amount of MnO was present on the surface of the catalyst2，MoO3And WO3It is explained that the active component on the surface of the catalyst synthesized by the method exists in a high valence state, and has strong oxidizing ability. In addition, MoO3Is added to prevent SO2Adsorbing on the surface of the catalyst to prevent SO2Further to SO3The sulfur resistance of the catalyst is enhanced. And WO3The addition of (2) obviously enhances the catalyst in high concentration CO2Catalytic activity in the flue gas present.

Claims (4)

1. A catalyst suitable for low-temperature catalytic oxidation of mercury in oxygen-rich combustion flue gas is characterized in that: the catalyst comprises 5-10% of manganese dioxide, 5-8% of molybdenum trioxide and 2-10% of tungsten trioxide by mass percentage, and the balance of the catalyst is a multi-walled carbon nanotube.
2. The catalyst of claim 1, wherein: the catalyst is ground into 80-325 meshes.
3. The method of preparing the catalyst of claim 1, comprising the steps of:
(1) mixing 80-88 parts by weight of multi-walled carbon nanotubes with deionized water 20 times of the mass of the multi-walled carbon nanotubes, and stirring uniformly at room temperature to obtain a mixture AI;
(2) taking dilute HNO according to the 1/5 volume of the deionized water in the step (1)3Adding the mixture into the mixture AI, and uniformly stirring at room temperature to obtain a mixture AII;
(3) adding citric acid into the mixture AII according to the volume of 1/10 of the deionized water in the step (1), and uniformly stirring at room temperature to obtain a mixture AIII;
(4) weighing 10.29-20.58 parts by weight of Mn (NO)3)2Dissolving in deionized water to obtain a solution BI; weighing 5-8 parts by weight of molybdenum trioxide, and dissolving the molybdenum trioxide in the HNO in the step (2)3Obtaining solution BII in ammonia water with the same volume; weighing 2.187-10.936 parts by weight of ammonium tungstate, and dissolving in 1/5 parts by volume of deionized water in the step (1) to obtain a solution BIII;
(5) introducing the solution BI, the BII and the BIII obtained in the step (4) into the mixture AIII in sequence, then adding concentrated nitric acid to adjust the pH value to 1.0, shaking for 24h at 50 ℃, then heating to 80 ℃ and drying for 48h at 80 ℃ to obtain solid A;
(6) and (5) placing the solid A obtained in the step (5) in a muffle furnace, heating to 400 ℃, calcining for 5 hours in an inert atmosphere, and grinding to obtain the catalyst.
4. The production method according to claim 3, characterized in that: in the step (6), the temperature of the solid is increased according to the temperature increase rate of 10 ℃/min.
CN202111009966.8A 2021-08-31 2021-08-31 Catalyst suitable for low-temperature catalytic oxidation of mercury in oxygen-rich combustion flue gas and preparation method thereof Pending CN113649037A (en)

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104028265A (en) * 2014-05-28 2014-09-10 淮阴工学院 Attapulgite-based catalyst for removing elemental mercury in smoke
CN106215949A (en) * 2016-08-02 2016-12-14 上海应用技术学院 A kind of low-temperature selective catalytic reduction denitration catalyst and preparation method thereof
CN107262110A (en) * 2017-06-22 2017-10-20 华中科技大学 A kind of ternary composite type denitration demercuration catalyst and preparation method thereof
CN110252333A (en) * 2019-07-04 2019-09-20 湖北工程学院 A kind of preparation method and application of SCR demercuration catalyst
CN110813310A (en) * 2019-10-29 2020-02-21 华中科技大学 Catalyst for synergistic denitration and demercuration and preparation method thereof
CN111686716A (en) * 2020-07-29 2020-09-22 江西省环境保护科学研究院 WOxLow-temperature SCR (selective catalytic reduction) flue gas denitration catalyst with modified carbon nano tube loaded with metal oxide, and preparation method and application thereof

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104028265A (en) * 2014-05-28 2014-09-10 淮阴工学院 Attapulgite-based catalyst for removing elemental mercury in smoke
CN106215949A (en) * 2016-08-02 2016-12-14 上海应用技术学院 A kind of low-temperature selective catalytic reduction denitration catalyst and preparation method thereof
CN107262110A (en) * 2017-06-22 2017-10-20 华中科技大学 A kind of ternary composite type denitration demercuration catalyst and preparation method thereof
CN110252333A (en) * 2019-07-04 2019-09-20 湖北工程学院 A kind of preparation method and application of SCR demercuration catalyst
CN110813310A (en) * 2019-10-29 2020-02-21 华中科技大学 Catalyst for synergistic denitration and demercuration and preparation method thereof
CN111686716A (en) * 2020-07-29 2020-09-22 江西省环境保护科学研究院 WOxLow-temperature SCR (selective catalytic reduction) flue gas denitration catalyst with modified carbon nano tube loaded with metal oxide, and preparation method and application thereof

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
向三明;许柱;李宝荣;茅佳俊;: "碳纳米管的制备、改性以及应用研究进展", 轻工科技 *

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