CN117619135A - Flue gas denitration method - Google Patents
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- CN117619135A CN117619135A CN202210970251.7A CN202210970251A CN117619135A CN 117619135 A CN117619135 A CN 117619135A CN 202210970251 A CN202210970251 A CN 202210970251A CN 117619135 A CN117619135 A CN 117619135A
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- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 title claims abstract description 87
- 239000003546 flue gas Substances 0.000 title claims abstract description 87
- 238000000034 method Methods 0.000 title claims abstract description 33
- 239000003054 catalyst Substances 0.000 claims abstract description 112
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims abstract description 42
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 claims abstract description 30
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- 229910052720 vanadium Inorganic materials 0.000 claims abstract description 25
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- QGLKJKCYBOYXKC-UHFFFAOYSA-N nonaoxidotritungsten Chemical compound O=[W]1(=O)O[W](=O)(=O)O[W](=O)(=O)O1 QGLKJKCYBOYXKC-UHFFFAOYSA-N 0.000 claims abstract description 8
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- 239000010936 titanium Substances 0.000 description 19
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- 238000010531 catalytic reduction reaction Methods 0.000 description 6
- HSJPMRKMPBAUAU-UHFFFAOYSA-N cerium(3+);trinitrate Chemical compound [Ce+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O HSJPMRKMPBAUAU-UHFFFAOYSA-N 0.000 description 6
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- DUFCMRCMPHIFTR-UHFFFAOYSA-N 5-(dimethylsulfamoyl)-2-methylfuran-3-carboxylic acid Chemical compound CN(C)S(=O)(=O)C1=CC(C(O)=O)=C(C)O1 DUFCMRCMPHIFTR-UHFFFAOYSA-N 0.000 description 1
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 1
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- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 description 1
- 229910021542 Vanadium(IV) oxide Inorganic materials 0.000 description 1
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- APUPEJJSWDHEBO-UHFFFAOYSA-P ammonium molybdate Chemical compound [NH4+].[NH4+].[O-][Mo]([O-])(=O)=O APUPEJJSWDHEBO-UHFFFAOYSA-P 0.000 description 1
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- VYLVYHXQOHJDJL-UHFFFAOYSA-K cerium trichloride Chemical compound Cl[Ce](Cl)Cl VYLVYHXQOHJDJL-UHFFFAOYSA-K 0.000 description 1
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- Catalysts (AREA)
- Exhaust Gas Treatment By Means Of Catalyst (AREA)
Abstract
The invention provides a flue gas denitration method, which comprises the steps of enabling flue gas to contact with a corrugated plate type catalyst in the presence of ammonia gas to carry out denitration treatment; the corrugated plate type catalyst comprises a carrier and an active component, wherein the active component comprises oxides of cerium, vanadium and tungsten; the mass ratio of the cerium oxide to the carrier is (5-20): 100, the mass ratio of the vanadium oxide to the carrier is (0.5-10): 100, wherein the mass ratio of the tungsten oxide to the carrier is (1-12): 100, has the advantages of high denitration efficiency, good stability and the like, and effectively reduces the emission of pollutants.
Description
Technical Field
The invention belongs to the technical field of flue gas treatment, and particularly relates to a flue gas denitration method.
Background
With the rapid development of economic and industrial production in China, the emission of nitrogen oxides (NOx) is increased, and the nitrogen oxides (NOx) can cause pollution such as photochemical smog and greenhouse effect, so that the human body health is seriously endangered. In order to promote the comprehensive development of emission reduction technology, how to reduce the generation and emission of nitrogen oxide exhaust gas is one of the main problems of concern.
The Selective Catalytic Reduction (SCR) method is to react with NOx in the flue gas by using a reducing agent under the action of a catalyst to generate nontoxic and pollution-free N 2 And H 2 O, a relatively well established NOx purification method in the prior art, wherein the SCR technology (NH 3 SCR) is widely used in emission control of industrial fixed source NOx.
The catalyst is a core component of the SCR process, and directly influences the catalytic activity of the catalyst, thereby influencing the conversion efficiency of NOx. For example, the catalyst disclosed in patent documents CN201110345605 and CN101352679A, CN102500424A, CN107138150B has a small specific surface area and uneven component distribution, affects the denitration effect, and is easily cracked, difficult to mold and easily broken.
Disclosure of Invention
The flue gas denitration method provided by the invention has the advantages that the flue gas is contacted with the corrugated plate type catalyst to carry out denitration treatment, the denitration efficiency is high, the stability is good, and the like, and the emission of pollutants is effectively reduced.
In one aspect of the invention, a flue gas denitration method is provided, wherein flue gas is contacted with a corrugated plate type catalyst in the presence of ammonia gas, and then the flue gas is fedPerforming denitration treatment; the corrugated plate type catalyst comprises a carrier and an active component, wherein the active component comprises oxides of cerium, vanadium and tungsten; the mass ratio of cerium oxide to the carrier is (5-20): 100, the mass ratio of the oxide of vanadium to the carrier is (0.5-10): 100, the mass ratio of tungsten oxide to carrier is (1-12): 100; wherein the oxide mass of cerium is represented by CeO 2 Calculated as V, the oxide mass of the vanadium 2 O 5 The mass of the tungsten oxide is calculated as WO 3 And (5) counting.
According to one embodiment of the invention, the molar ratio of nitrogen oxides in the ammonia flue gas is: (0.8-1.2): 1, wherein the nitrogen oxides are calculated as nitrogen atoms.
According to one embodiment of the invention, ammonia gas is injected into the denitration reactor, and then the flue gas enters the denitration reactor, so that the flue gas contacts with the corrugated plate type catalyst in the denitration reactor.
According to one embodiment of the invention, the temperature of the flue gas entering the denitration reactor is 260-420 ℃.
According to one embodiment of the invention, the ammonia gas has a volume concentration of 100mg/Nm 3 ～1200mg/Nm 3 。
According to one embodiment of the invention, the thickness of the corrugated-plate type catalyst is 0.2mm-0.6mm, the peak width of the corrugated-plate type catalyst is 4mm-8mm, and the peak height of the corrugated-plate type catalyst is 4mm-10mm.
According to one embodiment of the invention, the volume space velocity is 6000h -1 ～13000h -1 。
According to one embodiment of the invention, the support comprises a titania support.
According to an embodiment of the present invention, a method for preparing a corrugated-plate catalyst includes the steps of: uniformly mixing a cerium source, a nano oxide and a carrier by adopting a sol-gel method, and obtaining an intermediate after first drying and first roasting; dissolving nano oxides in the intermediate by adopting alkali solution to obtain an alkali-soluble product; mixing an alkali-soluble product, a vanadium source, a tungsten source, a binder and water to form pug, and stamping the pug to obtain a corrugated sheet, wherein the mass of the water is 5% -60% of that of the pug; and stacking a plurality of corrugated sheets to obtain a blank body, and performing second drying and second roasting to obtain the corrugated plate type catalyst.
According to one embodiment of the invention, each corrugated sheet has a thickness of 0.2mm to 0.6mm, a peak width of 4mm to 8mm, and a peak height of 4mm to 10mm.
According to an embodiment of the present invention, the nano-oxide includes at least one of nano-alumina and nano-silica.
The implementation of the invention has at least the following beneficial effects:
the flue gas denitration method provided by the invention adopts the corrugated plate type catalyst for denitration, and the corrugated plate type catalyst has the advantages of good formability, convenience in transportation, small occupied area, uniform dispersion of active components, synergistic effect, great improvement of catalytic activity of the catalyst, capability of leading ammonia gas to preferentially perform catalytic reduction reaction with nitrogen oxides when contacting with flue gas, high denitration efficiency, good stability and the like.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the present invention more apparent, the technical solutions in the embodiments of the present invention will be clearly and completely described in the following in conjunction with the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
According to the flue gas denitration method provided by the invention, in the presence of ammonia gas, the flue gas is contacted with a corrugated plate type catalyst to carry out denitration treatment; the corrugated plate type catalyst comprises a carrier and an active component, wherein the active component comprises oxides of cerium, vanadium and tungsten; the mass ratio of cerium oxide to the carrier is (5-20): 100, the mass ratio of the oxide of vanadium to the carrier is (0.5-10): 100, the mass ratio of tungsten oxide to carrier is (1-12): 100; wherein the oxide mass of cerium is represented by CeO 2 Calculated as V, the oxide mass of vanadium 2 O 5 Oxidation of tungstenThe mass of the substances is WO 3 Meter with a meter body
The inventor finds that in the corrugated plate type catalyst, active components cerium, tungsten, vanadium and titanium have a synergistic effect, so that ammonia gas and nitrogen oxides can be subjected to catalytic reduction reaction preferentially, and the denitration efficiency is improved; secondly, the corrugated plate type denitration catalyst has the advantages of high molding rate, low manufacturing cost, low breakage rate, small volume and the like, and can reduce occupied space and cost. The method is used for flue gas denitration treatment, and has the advantages of high denitration efficiency, good stability, suitability for higher airspeed environments and the like.
The invention provides a flue gas denitration method, which uses a corrugated plate type catalyst as a catalyst to carry out SCR denitration, and comprises the following specific processes: placing the corrugated plate type denitration catalyst in a reactor, introducing mixed gas containing ammonia gas, heating, and simultaneously introducing flue gas to enable the flue gas to fully contact with the catalyst for denitration treatment.
In the invention, the flue gas can be selected from flue gas discharged by conventional equipment, such as flue gas of a coal-fired power plant and flue gas of an ethylene cracking furnace.
In some embodiments, the molar ratio of ammonia to nitrogen oxides in the flue gas is: (0.8-1.2): 1, for example 0.8: 1.1: 1. 1.1: 1. 1.2:1 or any two thereof, wherein the mole number of ammonia gas and nitrogen oxide is calculated as the mole number of nitrogen atoms.
In the present invention, the temperature of the denitration treatment is 260 ℃ to 420 ℃, and in the above embodiment, the temperature of the flue gas entering the denitration reactor can be 260 ℃ to 420 ℃.
The ammonia gas of the present invention may be introduced by conventional means, for example in the form of ammonia gas, preferably by mixing the ammonia gas with other gases to form a mixer containing the ammonia gas, and then introducing the mixed gas, in some embodiments, by injecting the mixed gas containing the ammonia gas into the denitration reactor, and then introducing the flue gas into the denitration reactor, and contacting the flue gas with the corrugated-plate catalyst in the denitration reactor.
In the above embodiment, the concentration of ammonia gas is determined according to the concentration of NOx in the flue gas and may be 100mg/Nm 3 ～1200mg/Nm 3 。
In the above examples, the volume space velocity was 6000h -1 ～13000h -1 。
The carrier of the present invention may be selected from carriers conventional in the art, for example, the carrier may be a titania carrier.
The preparation method of the corrugated plate type catalyst comprises the following steps: uniformly mixing a cerium source, a nano oxide and a carrier by adopting a sol-gel method, and obtaining an intermediate after first drying and first roasting; dissolving nano oxides in the intermediate by adopting alkali solution to obtain an alkali-soluble product; mixing an alkali-soluble product, a vanadium source, a tungsten source, a binder and water to form pug, and stamping the pug to obtain a corrugated sheet, wherein the mass of the water is 5% -60% of that of the pug; and stacking a plurality of corrugated sheets to obtain a blank body, and performing second drying and second roasting to obtain the corrugated plate type catalyst.
In the implementation of the present invention, the preparation method of the corrugated-plate catalyst may include the following steps: (1) mixing a titanium source and an alcohol solvent to obtain a solution A; mixing a cerium source, a nano oxide, a blocking agent and glacial acetic acid, and regulating the pH to 1-5 to obtain a solution B, wherein the nano oxide comprises at least one of nano alumina and nano silicon dioxide; (2) Adding the solution B into the solution A to form gel, and obtaining an intermediate after first drying and first roasting; (3) Alkali solution is adopted to carry out alkali dissolution on the intermediate to obtain an alkali dissolution product; (4) Mixing an alkali-soluble product, a vanadium source, a tungsten source, a dispersing agent and a binder to obtain pug; stamping pug into corrugated sheets, stacking a plurality of corrugated sheets to obtain a catalyst blank, and performing second drying and second roasting to obtain the corrugated plate type denitration catalyst.
The invention provides a preparation method of a corrugated plate type denitration catalyst, which comprises the steps of firstly adopting a sol-gel method to mix cerium (Ce) into titanium dioxide (TiO) 2 ) In the crystal lattice, the nano oxide is wrapped in titanium dioxide, alkali solution is adopted to carry out alkali dissolution, the nano oxide is removed to obtain alkali dissolution products, finally the alkali dissolution products are mixed with vanadium sources and tungsten sources to form pugs, the pugs are punched into corrugated sheets, and a plurality of corrugated sheets are laminated to formThe corrugated plate type denitration catalyst is obtained after drying and roasting, so that vanadium and tungsten oxides are loaded on a cerium-doped titanium dioxide carrier, and the corrugated plate type denitration catalyst has the advantages of high forming rate, high catalytic activity and the like.
The inventors have found that, in the steps (1) and (2), by adding the solution B to the solution A, the cerium source, the titanium source and the nano-oxide are mixed, and the cerium (Ce) is doped into the titanium dioxide (TiO) 2 ) The lattice, cause titanium dioxide lattice defect, help oxygen vacancy's production, can also make nanometer oxide wrap up in titanium dioxide simultaneously, in step (3), adopt the alkali solution to carry out the alkali dissolution to the midbody, can dissolve out the nanometer oxide in the midbody, greatly increased the lattice defect and the specific surface area of midbody, in step (4), alkali dissolution product and vanadium source, tungsten source fully contact, active component tungsten, vanadium benefit to in nano space and the lattice defect, further improved the dispersion of active component tungsten, vanadium, make the catalyst corrugated plate simultaneously, be favorable to improving the shaping rate of preparing the catalyst. In the preparation process, the active components cerium, tungsten and vanadium oxide can be more uniformly loaded on the titanium dioxide carrier, which is beneficial to improving the catalytic activity of the catalyst.
In the step (1), the titanium source comprises at least one of tetrabutyl titanate, titanium sulfate, titanium isopropoxide and titanium tetrachloride, the alcohol solvent comprises ethanol, and the volume ratio of the alcohol solvent to the titanium source is (3-20): 1, preferably (5-10): 1. the alcohol solvent can enable the titanium source to form titanium hydroxide in the solution A, which is favorable for forming titanium dioxide crystals after subsequent roasting.
In the above embodiment, the cerium source includes at least one of cerium nitrate, cerium sulfate, and cerium chloride. The mass ratio of the cerium source to the titanium source is (5-20): 100, preferably (6-12): 100, wherein the mass of the cerium source is CeO 2 The mass of the titanium source is calculated as TiO 2 And (5) counting.
In the above embodiment, the nano oxide includes at least one of nano alumina and nano silica, and may also be nano alumina sol, and the particle size of the nano oxide may be 1nm to 50nm, preferably 1nm to 30nm.
In the above examples, the mass ratio of the nano oxide to the titanium source is (0.5-5): 100, preferably (0.5-2): 100, wherein the mass of the nano-oxide is as Al 2 O 3 And (5) counting.
In the above examples, the mass ratio of barrier agent to titanium source is (0.3-5): 100, preferably (0.5-2): 100, the blocking agent may be polyethylene glycol, and the molecular weight of the polyethylene glycol may be 400-10000, preferably 1500-2000.
In the above examples, glacial acetic acid has a mass ratio of catalytic action to titanium source of (1-5): 100, where the mass of the titanium source is TiO 2 And (5) counting.
In the implementation of the present invention, for example, cerium source, nano oxide, polyethylene glycol, glacial acetic acid, ethanol and water may be mixed and stirred, and an acid solution is added to adjust the pH to 1-5, so as to obtain solution B, wherein the pH is preferably 2-4.
In the above embodiment, the step (1) of adjusting the pH to 1-5 may be performed by adding hydrochloric acid, wherein the hydrochloric acid may be diluted hydrochloric acid or concentrated hydrochloric acid. Regulating pH value of the reaction system, and controlling the speed of the reaction of metal ions and hydroxyl groups to generate polymer.
In the implementation process of the present invention, the step (2) specifically includes: slowly dripping the solution B into the solution A, stirring, controlling the temperature at a certain level, continuously stirring after the dripping is finished to obtain uniform sol, obtaining gel, aging the gel, and performing first drying and first roasting to obtain an intermediate.
In the step (2), on one hand, cerium is doped in the titanium dioxide crystal lattice to cause crystal lattice defects, and after the first roasting, the crystal lattice defects are more stable, and on the other hand, the nano oxide is wrapped in the titanium dioxide, so that more nano spaces and crystal lattice defects can be formed after subsequent alkali treatment.
In the above embodiment, the solution B is uniformly dispersed in the solution a, and the stirring process may be mechanical stirring or ultrasonic assistance. The aging time may be 0.5 to 10 days, preferably 2 to 5 days.
In the above examples, the temperature is generally controlled to be 10℃to 90℃and preferably 20℃to 60 ℃. In the practice of the present invention, the temperature of solution A may be controlled to be 10℃to 90℃and then solution B may be added to solution A in the above temperature range.
In the step (2), the temperature of the first drying is 60-180 ℃, preferably 60-90 ℃, and the time is 5-50 h, preferably 8-30 h.
In the above examples, the temperature of the first firing is 400 to 680 ℃, preferably 450 to 610 ℃, for 2 to 35 hours, preferably 3 to 20 hours.
In the step (3), the intermediate is subjected to alkali dissolution by adopting alkali solution, and the alkali solution can dissolve out nano oxides in the intermediate to form lattice defects and nano spaces, so that the lattice defects and the specific surface area are further increased.
In the above embodiment, the solvent of the alkali solution includes at least one of sodium hydroxide and potassium hydroxide, the concentration of the alkali solution is 0.1mol/L to 5.0mol/L, and the volume ratio of the alkali solution to the catalyst intermediate is (0.5 to 8): 1, preferably (0.8-3): 1.
in the above embodiment, the method further comprises washing the solid generated after alkali dissolution, wherein deionized water can be used as a washing liquid for washing, the washing times are preferably 3-5 times, and then the alkali dissolution product is obtained through filtration.
In the step (4), the alkali-soluble product, the vanadium source, the tungsten source, the dispersing agent, the binder and the pore-forming agent are mixed to form pug, the pug is firstly subjected to forming treatment, the pug is punched into corrugated sheets, a plurality of corrugated sheets are arranged in a stacked mode, a catalyst blank is obtained, and the corrugated-plate type denitration catalyst is obtained after secondary drying and secondary roasting.
In the above embodiment, the dispersant includes at least one of polyacrylamide and polyvinylpyrrolidone, and the mass ratio of the dispersant to the titanium source is (0.2-3): 100.
in the above embodiment, the binder includes at least one of carboxymethyl cellulose and hydroxypropyl cellulose, and the mass ratio of the second binder to the titanium source is (0.5-2): 100.
in the specific implementation process of the invention, alkali dissolution products, vanadium sources, tungsten sources, dispersing agents, binders, pore formers and water can be mixed to prepare pugs, then the pugs are punched into corrugated sheets, a plurality of corrugated sheets are arranged in a lamination mode to obtain catalyst blanks, and the catalyst blanks are subjected to secondary drying and secondary roasting to obtain corrugated plate type denitration catalysts, wherein the pore formers can be at least one of polyethylene oxide, polymethyl methacrylate and sesbania powder, and the mass ratio of the pore formers to the titanium sources is (0.2-2): 100.
in the above embodiments, the mass content of water in the pug may be 5% -60%, preferably 12-40%.
In the above embodiment, the pH is adjusted to 7-12, preferably 7.5-10.5, before forming the pug, which is helpful for forming. Wherein ammonia or other alkaline agents may be used to adjust the pH.
In the above embodiment, each corrugated sheet may be bonded with a resin adhesive, for example, an epoxy resin adhesive.
In the above examples, the second drying is carried out at a temperature of 50 ℃ to 150 ℃, preferably 60 ℃ to 100 ℃, for a period of 1 to 30 days, preferably 5 to 15 days, and the ambient humidity is controlled to be 40% to 99.5%, preferably 75% to 98%, during the second drying.
In the above examples, the second calcination temperature is 450-680 ℃, preferably 450-610 ℃, for 2-40 hours, preferably 3-20 hours.
In the above embodiment, the second firing is temperature programmed according to the following procedure: and (3) controlling the heating rate to be not more than 1 ℃/min, roasting at a constant temperature for 2-40 h after the temperature reaches the preset temperature of 450-680 ℃, then cooling to be not more than 4 ℃/min, cooling to below 50 ℃, and finishing roasting.
In the above embodiment, the vanadium source includes at least one of ammonium vanadate and ammonium metavanadate, preferably ammonium vanadate, and the mass ratio of the vanadium source to the titanium source is (0.5-10): 100, preferably (0.5-5): 100, wherein the mass of the vanadium source is V 2 O 5 Meter, titanium sourceBy mass of TiO 2 And (5) counting.
In the above embodiment, the tungsten source includes at least one of ammonium tungstate and ammonium metatungstate, preferably ammonium tungstate, and the mass ratio of the tungsten source to the titanium source is (1-12): 100, preferably (2-8): 100, wherein the tungsten source is as in WO 3 Titanium source is TiO 2 And (5) counting.
The corrugated plate type denitration catalyst provided by the invention is prepared by adopting the preparation method, and the corrugated plate type denitration catalyst can be prepared by taking titanium dioxide as a carrier and cerium, tungsten and vanadium as active components of the denitration catalyst.
In the above embodiment, the size of the corrugated plate type denitration catalyst is determined according to practical situations, for example, the thickness of each corrugated sheet may be 0.2mm to 0.6mm, the width of the peak may be 4mm to 8mm, and the height of the peak may be 4mm to 10mm.
In the corrugated plate type denitration catalyst, cerium is doped in a crystal lattice of titanium dioxide, tungsten and vanadium oxides are loaded on a titanium dioxide carrier, wherein active components cerium, tungsten and vanadium are uniformly dispersed on the titanium dioxide carrier, and cerium, tungsten, vanadium and titanium dioxide have synergistic effects, so that ammonia gas and nitrogen oxides can be subjected to catalytic reduction reaction preferentially, and denitration efficiency is improved; secondly, the cerium doping improves the alkali metal poisoning resistance and the alkali earth metal poisoning resistance of the catalyst; in addition, the corrugated plate type denitration catalyst has the advantages of high molding rate, low manufacturing cost, low breakage rate, small volume and the like, and can reduce occupied space and cost.
According to the flue gas denitration method provided by the invention, the corrugated plate type catalyst is used as a catalyst for SCR denitration, and active components in the catalyst cooperate, so that ammonia gas and nitrogen oxides can be subjected to catalytic reduction reaction preferentially, and the denitration efficiency is improved.
In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions in the embodiments of the present invention will be clearly and completely described in the following in conjunction with the embodiments of the present invention.
In each of the examples and comparative examples, the other chemicals used were commercially available chemically pure reagents and were evaluated using the following assay methods:
(1) Specific surface area
The specific surface area of the sample was measured by BET adsorption.
(2) Denitration efficiency
The flue gas is subjected to denitration treatment according to the following flue gas denitration method:
placing the catalyst in a fixed bed reactor, introducing mixed gas containing oxygen and nitrogen, and simultaneously introducing flue gas to enable the flue gas to fully contact with the catalyst for denitration treatment; measuring the concentration of each component in the flue gas and the tail gas by a flue gas analyzer, and according to the NOx conversion rate= (concentration of NOx in the flue gas-concentration of NOx in the tail gas)/concentration of NOx in the flue gas;
wherein the flue gas analyzer is a flue gas continuous on-line analyzer, siemens ULTRAMAT23; o in the reactor 2 3% (v) of nitrogen as balance gas; NO, N 2、 NH 3 The manufacturers of (A) are Dalianda gas Limited company, O 2 From public engineering air pipe network with pressure of 0.4-0.6mpa and N 2 From a utility nitrogen pipeline network with a purity of 99.0% (V) and a pressure of 0.4-0.6Mpa;
the evaluation results are shown in Table 1.
Example 1:
a catalyst prepared according to the following conditions:
mixing 100g of tetrabutyl titanate with first ethanol to form a solution A; mixing 8g of cerium nitrate, 2.0g of nano aluminum sol, 0.5g of polyethylene glycol, 5mL of glacial acetic acid and second ethanol, regulating the pH to 2 by adopting hydrochloric acid, and performing ultrasonic treatment to obtain a solution B; wherein the mass of tetrabutyl titanate is TiO 2 Metering, the mass of cerium nitrate is CeO 2 The mass of the nanometer aluminum sol is calculated as Al 2 O 3 Counting; the volume ratio of the first ethanol to the tetrabutyl titanate is 10:1, the volume ratio of the second ethanol to the first ethanol is 1:1, a step of;
slowly adding the solution B into the solution A, stirring, aging at room temperature for 3 days, drying at 70 ℃ for 20 hours, roasting in a muffle furnace at 450 ℃ for 20 hours, and grinding the obtained solid to obtain an intermediate;
impregnating the intermediate by adopting sodium hydroxide solution with the concentration of 0.1mol/L, washing and filtering to obtain an impregnated product, wherein the volume ratio of the sodium hydroxide solution to the intermediate is 1:1, a step of;
mixing the impregnated product with 5.0g of ammonium vanadate, 2.0g of ammonium metatungstate, 8.0g of carboxymethyl cellulose, 1.0g of polyvinylpyrrolidone, 0.3g of polymethyl methacrylate and water to prepare a mud material with 15% of water content, adjusting the pH value to 8.0, stamping corrugated sheets, spraying epoxy resin glue between the corrugated sheets, laminating and assembling to obtain a corrugated plate type denitration catalyst blank, drying the blank, and roasting at 520 ℃ for 12 hours to obtain the corrugated plate type NH 3 -SCR denitration catalyst C1; wherein the mass of the ammonium metatungstate is WO 3 Calculated as V 2 O 5 Counting;
catalyst C1 was cut into 3X 12cm columns and charged into a reactor with a catalyst loading of 108mL, and the denitration effect of the catalyst was evaluated:
injecting ammonia into a denitration reactor, then enabling the flue gas to enter the denitration reactor, enabling the flue gas to contact with a catalyst, and carrying out denitration treatment; flue gas reaction conditions: the reaction temperature is 260 ℃ and the airspeed is 6000h -1 The concentration of NO in the flue gas is 500mg/Nm 3 ，NH 3 Concentration of 600mg/Nm 3 ；
The specific surface area of the catalyst obtained is 48m 2 /g，NO x The conversion was 90.7%.
Example 2
A catalyst prepared according to the following conditions:
mixing 100g of titanium sulfate with a first ethanol to form a solution A; mixing 12.0g of cerium sulfate, 1.0g of nano silicon dioxide, 1.5g of polyethylene glycol, 2mL of glacial acetic acid and second ethanol, regulating the pH to 3 by adopting hydrochloric acid, and performing ultrasonic treatment to obtain a solution B; wherein the mass of the titanium sulfate is TiO 2 The mass of cerium sulfate is calculated by CeO 2 The mass of the nano silicon dioxide is calculated as Al 2 O 3 Counting; the volume ratio of the first ethanol to the titanium sulfate is 5:1, the volume ratio of the second ethanol to the first ethanol is 1.5:1, a step of;
slowly adding the solution B into the solution A, stirring, aging at room temperature for 4 days, drying at 90 ℃ for 12 hours, roasting in a muffle furnace at 450 ℃ for 7 hours, and grinding the obtained solid to obtain an intermediate;
impregnating the intermediate by adopting a sodium hydroxide solution with the concentration of 2mol/L, washing and filtering to obtain an impregnated product, wherein the volume ratio of the sodium hydroxide solution to the intermediate is 1.2:1, a step of;
mixing the impregnated product with 5.0g of ammonium metavanadate, 8.0g of ammonium metatungstate, 7.0g of carboxymethyl cellulose, 0.8g of polyvinylpyrrolidone, 1.0g of polyoxyethylene and water to prepare a pug with the water content of 25%, adjusting the pH value to be 10.0, stamping corrugated sheets, spraying epoxy resin glue between the corrugated sheets, laminating and assembling to obtain a corrugated plate type denitration catalyst blank, drying the blank, and roasting at 550 ℃ for 8 hours to obtain a corrugated plate type NH 3 -SCR denitration catalyst C2; wherein the mass of the ammonium metatungstate is WO 3 Calculated by the mass of the ammonium metavanadate in terms of V 2 O 5 Counting;
catalyst C2 was cut into 3X 12cm columns and charged into a reactor, the catalyst loading was 108mL, and the denitration effect of the catalyst was evaluated:
injecting ammonia into a denitration reactor, then enabling the flue gas to enter the denitration reactor, enabling the flue gas to contact with a catalyst, and carrying out denitration treatment; flue gas reaction conditions: the reaction temperature is 420 ℃ and the space velocity is 13000h -1 The concentration of NO in the flue gas is 800mg/Nm 3 ，NH 3 Concentration of 800mg/Nm 3 ；
The specific surface area of the catalyst obtained above was 57m 2 /g，NO x The conversion was 98.0%.
Example 3
A catalyst prepared according to the following conditions:
mixing 100g of titanium isopropoxide with a first ethanol to form a solution A; mixing 6.0g of cerium sulfate, 0.5g of nano alumina, 1.5g of polyethylene glycol, 3mL of glacial acetic acid and second ethanol, regulating the pH to 4 by adopting hydrochloric acid, and performing ultrasonic treatment to obtain a solution B; wherein the mass of the titanium isopropoxide is TiO 2 Meter of cerium sulfateThe mass is CeO 2 The mass of the nano silicon dioxide is calculated as Al 2 O 3 Counting; the volume ratio of the first ethanol to the titanium sulfate is 7:1, the volume ratio of the second ethanol to the first ethanol is 1:1, a step of;
slowly adding the solution B into the solution A, stirring, aging at room temperature for 5 days, drying at 80 ℃ for 20 hours, roasting in a muffle furnace at 450 ℃ for 6 hours, and grinding the obtained solid to obtain an intermediate;
impregnating the intermediate by adopting sodium hydroxide solution with the concentration of 1.5mol/L, washing and filtering to obtain an impregnated product, wherein the volume ratio of the sodium hydroxide solution to the intermediate is 2:1, a step of;
mixing the impregnated product with 2.0g of ammonium vanadate, 4.0g of ammonium tungstate, 1.6g of carboxymethyl cellulose, 1.6g of polyvinylpyrrolidone, 1.0g of polyoxyethylene and water to prepare pug with the water content of 25%, adjusting the pH value to 9.0, stamping corrugated sheets, spraying epoxy resin glue between the corrugated sheets, laminating and assembling to obtain a corrugated plate type denitration catalyst blank, drying the blank, and roasting at 600 ℃ for 5 hours to obtain a corrugated plate type NH 3 -SCR denitration catalyst C3; wherein the mass of ammonium tungstate is that of WO 3 Calculated as V 2 O 5 Counting;
catalyst C3 was cut into 3X 12cm columns and charged into a reactor with a catalyst loading of 108mL, and the denitration effect of the catalyst was evaluated:
injecting ammonia into a denitration reactor, then enabling the flue gas to enter the denitration reactor, enabling the flue gas to contact with a catalyst, and carrying out denitration treatment; flue gas reaction conditions: reaction temperature 380 ℃ and space velocity 10000h -1 The concentration of NO in the flue gas is 800mg/Nm 3 ，NH 3 Concentration of 800mg/Nm 3 ；
The specific surface area of the catalyst obtained above was 52m 2 /g，NO x The conversion was 99.3%.
Example 4
A catalyst prepared according to the following conditions:
mixing 100g of titanium isopropoxide with a first ethanol to form a solution A;mixing 7.0g of cerium sulfate, 1.5g of nano aluminum oxide, 2g of polyethylene glycol, 3mL of glacial acetic acid and second ethanol, regulating the pH to 3 by adopting hydrochloric acid, and performing ultrasonic treatment to obtain a solution B; wherein the mass of the titanium isopropoxide is TiO 2 The mass of cerium sulfate is calculated by CeO 2 The mass of the nano alumina is calculated as Al 2 O 3 Counting; the volume ratio of the first ethanol to the titanium sulfate is 6:1, the volume ratio of the second ethanol to the first ethanol is 1:1, a step of;
slowly adding the solution B into the solution A with the temperature of the solution A controlled to be 40 ℃, stirring, obtaining gel after the addition, aging the gel at room temperature for 3 days, drying the gel at 85 ℃ for 14 hours, roasting the gel in a muffle furnace at 500 ℃ for 6 hours, and grinding the obtained solid to obtain an intermediate;
impregnating the intermediate by adopting a sodium hydroxide solution with the concentration of 2mol/L, washing and filtering to obtain an impregnated product, wherein the volume ratio of the sodium hydroxide solution to the intermediate is 1:1, a step of;
mixing the impregnated product with 1.0g ammonium vanadate, 5.0g ammonium tungstate, 5.0g hydroxypropyl cellulose, 1.5g polyacrylamide, 1.0g sesbania powder and water to prepare pug with the water content of 30%, adjusting the pH value to 9.0, stamping corrugated sheets, spraying epoxy resin glue between the corrugated sheets, laminating and assembling to obtain a corrugated plate type denitration catalyst blank, drying the blank, and roasting at 600 ℃ for 5 hours to obtain corrugated plate type NH 3 -SCR denitration catalyst C3; wherein the mass of ammonium tungstate is that of WO 3 Calculated as V 2 O 5 Counting;
catalyst C3 was cut into 3X 12cm columns and charged into a reactor with a catalyst loading of 108mL, and the denitration effect of the catalyst was evaluated:
injecting ammonia into a denitration reactor, then enabling the flue gas to enter the denitration reactor, enabling the flue gas to contact with a catalyst, and carrying out denitration treatment; flue gas reaction conditions: reaction temperature is 350 ℃, and space velocity is 8000h -1 NO concentration in flue gas is 1200mg/Nm 3 ，NH 3 Concentration of 1200mg/Nm 3 ；
The specific surface area of the catalyst obtained is 54m 2 /g，NO x The conversion was 99.0%.
Example 5
A catalyst prepared according to the following conditions:
mixing 100g of tetrabutyl titanate with first ethanol to form a solution A; mixing 6.0g of cerium sulfate, 2g of nano aluminum oxide, 1g of polyethylene glycol, 3mL of glacial acetic acid and second ethanol, regulating the pH to 3 by adopting hydrochloric acid, and performing ultrasonic treatment to obtain a solution B; wherein the mass of tetrabutyl titanate is TiO 2 The mass of cerium sulfate is calculated by CeO 2 The mass of the nano alumina is calculated as Al 2 O 3 Counting; the volume ratio of the first ethanol to the titanium sulfate is 8:1, the volume ratio of the second ethanol to the first ethanol is 1:1, a step of;
slowly adding the solution B into the solution A with the temperature of the solution A controlled to be 40 ℃, stirring, obtaining gel after adding, aging the gel at room temperature for 3 days, drying the gel at 80 ℃ for 15 hours, roasting the gel in a muffle furnace at 470 ℃ for 6 hours, and grinding the obtained solid to obtain an intermediate;
impregnating the intermediate by adopting sodium hydroxide solution with the concentration of 3.5mol/L, washing and filtering to obtain an impregnated product, wherein the volume ratio of the sodium hydroxide solution to the intermediate is 1:1, a step of;
mixing the impregnated product with 0.7g ammonium metavanadate, 6.0g ammonium tungstate, 2.0g carboxymethyl cellulose, 1.0g polyacrylamide, 1.5g sesbania powder and water to prepare pug with the water content of 35%, adjusting the pH value to 9.0, stamping corrugated sheets, spraying epoxy resin glue between the corrugated sheets, laminating and assembling to obtain a corrugated plate type denitration catalyst blank, drying the blank, and roasting at 580 ℃ for 7 hours to obtain a corrugated plate type NH 3 -SCR denitration catalyst C5; wherein the mass of ammonium tungstate is that of WO 3 Calculated by the mass of the ammonium metavanadate in terms of V 2 O 5 Counting;
catalyst C5 was cut into 3X 12cm columns and charged into a reactor with a catalyst loading of 108mL, and the denitration effect of the catalyst was evaluated:
injecting ammonia into a denitration reactor, then enabling the flue gas to enter the denitration reactor, enabling the flue gas to contact with a catalyst, and carrying out denitration treatment; flue gas reaction conditions: reaction temperature 330 ℃ and space velocity 7000h -1 The concentration of NO in the flue gas is 600mg/Nm 3 ，NH 3 Gas concentration 550mg/Nm 3 ；
The specific surface area of the catalyst obtained above was 55m 2 /g，NO x The conversion was 91.1%.
Comparative example 1
Injecting ammonia into a denitration reactor, then enabling the flue gas to enter the denitration reactor, enabling the flue gas to contact with a catalyst, and carrying out denitration treatment; flue gas reaction conditions: reaction temperature 330 ℃ and space velocity 7000h -1 The concentration of NO in the flue gas is 600mg/Nm 3 ，NH 3 Gas concentration 550mg/Nm 3 ；
Wherein the catalyst takes a metal plate, a glass fiber corrugated plate and honeycomb ceramics as a carrier, and takes the quality of the carrier as a reference to load ZrO 2 Is 1.6% V 2 O 5 0.6% of WO 3 3.9% Pr 6 O 11 0.2%;
the specific surface area of the catalyst was 42m 2 /g；NO x The conversion was 85.7%.
Comparative example 2
Injecting ammonia into a denitration reactor, then enabling the flue gas to enter the denitration reactor, enabling the flue gas to contact with a catalyst, and carrying out denitration treatment; flue gas reaction conditions: the reaction temperature is 420 ℃ and the space velocity is 13000h -1 The concentration of NO in the flue gas is 800mg/Nm 3 ，NH 3 Concentration of 800mg/Nm 3 ；
Wherein the preparation of the catalyst comprises the following steps: will contain TiO 2 500g of titanyl sulfate was dissolved in the sulfuric acid solution to form a TiO-containing solution 2 35g/L solution and will contain ZrO 2 A total of 12g of zirconium acetate solution was added with a solution containing WO 3 Counting 20g of ammonium metatungstate solution, mechanically stirring for 2 hours, gradually adding ammonia water to adjust the pH value to 9.5, and filtering and washing after precipitation is completed; then the washed material is made into slurry with 50 percent of water content by deionized water, and V is added 2 O 5 Counting 5g of ammonium metavanadate solution, stirring while vibrating for 1.5h by ultrasonic waves, directly drying, and roasting for 8h at 620 ℃; the powder after roasting is mixed with MoO 3 4.5g of ammonium molybdate solution was added after stirring to prepare a slurry containing 30% of waterAdding 4g of urea, stirring for 40min, sealing and standing for 24h, extruding to form a corrugated plate, drying, coating 15g of nano tungsten oxide, and roasting at 620 ℃ for 8h to obtain a denitration catalyst;
the specific surface area of the catalyst obtained was 46m 2 /g，NO x The conversion was 96.3%.
Therefore, the flue gas denitration method provided by the invention adopts the corrugated plate type catalyst as the catalyst to perform SCR denitration, active components in the catalyst cooperate, the specific surface area of the catalyst is large, ammonia gas and nitrogen oxides can be subjected to catalytic reduction reaction preferentially, and the denitration efficiency is improved.
Of course, the present invention is capable of other various embodiments and its several details are capable of modification and variation in light of the present invention by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.
Claims (10)
1. A flue gas denitration method is characterized in that flue gas is contacted with a corrugated plate type catalyst in the presence of ammonia gas to carry out denitration treatment;
the corrugated plate type catalyst comprises a carrier and an active component, wherein the active component comprises cerium oxide, vanadium oxide and tungsten oxide;
the mass ratio of the cerium oxide to the carrier is (5-20): 100, the mass ratio of the vanadium oxide to the carrier is (0.5-10): 100, wherein the mass ratio of the tungsten oxide to the carrier is (1-12): 100;
wherein the oxide mass of cerium is CeO 2 Calculated as V, the oxide mass of the vanadium 2 O 5 The mass of the tungsten oxide is calculated as WO 3 And (5) counting.
2. The flue gas denitration method according to claim 1, wherein the molar ratio of the ammonia gas to the nitrogen oxides in the flue gas is: (0.8-1.2): 1, wherein the nitrogen oxides are in terms of nitrogen atoms.
3. The flue gas denitration method according to claim 1, wherein ammonia gas is injected into the denitration reactor, and then the flue gas is introduced into the denitration reactor, and the flue gas is brought into contact with a corrugated plate type catalyst in the denitration reactor.
4. The flue gas denitration method according to claim 1, wherein the temperature of flue gas entering the denitration reactor is 260 ℃ to 420 ℃.
5. The flue gas denitration method according to claim 1, wherein the concentration of ammonia gas is 100mg/Nm 3 ～1200mg/Nm 3 。
6. The flue gas denitration method according to claim 1, wherein the volume space velocity is 6000h -1 ～13000h -1 。
7. The flue gas denitration method according to claim 1, wherein the carrier includes a titania carrier.
8. The flue gas denitration method according to claim 1, characterized in that the preparation method of the corrugated-plate type catalyst comprises the following steps: uniformly mixing a cerium source, a nano oxide and a carrier by adopting a sol-gel method, and obtaining an intermediate after first drying and first roasting;
dissolving nano oxides in the intermediate by adopting alkali solution to obtain an alkali-soluble product;
mixing an alkali-soluble product, a vanadium source, a tungsten source, a binder and water to form pug, and stamping the pug to obtain a corrugated sheet, wherein the mass of the water is 5% -60% of that of the pug;
and stacking a plurality of corrugated sheets to obtain a blank body, and performing second drying and second roasting to obtain the corrugated plate type catalyst.
9. The flue gas denitration method according to claim 8, wherein the thickness of each corrugated sheet is 0.2mm to 0.6mm, the peak width is 4mm to 8mm, and the peak height is 4mm to 10mm.
10. The flue gas denitration method according to claim 8, wherein the nano-oxide includes at least one of nano-alumina and nano-silica.
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