Preparation method of SCR denitration catalyst with ultralow vanadium load by taking perovskite type composite oxide as carrier and prepared catalyst
阅读说明：本技术 以钙钛矿型复合氧化物为载体的超低钒负载量scr脱硝催化剂的制备方法、制得的催化剂 (Preparation method of SCR denitration catalyst with ultralow vanadium load by taking perovskite type composite oxide as carrier and prepared catalyst ) 是由 许晓龙 王光应 梁燕 赵羽 薛晚林 于 2021-08-03 设计创作，主要内容包括：本发明公开一种以钙钛矿型复合氧化物为载体的超低钒负载量SCR脱硝催化剂的制备方法,涉及脱硝催化剂技术领域,本发明包括以下步骤：(1)将偏钒酸铵溶于草酸溶液,充分搅拌,使偏钒酸铵完全溶解,得到偏钒酸铵溶液；所述偏钒酸铵溶液中偏钒酸铵浓度为2～6g/L；(2)将钙钛矿型复合氧化物使用玛瑙研钵研细后过筛；(3)将偏钒酸铵溶液与钙钛矿型复合氧化物混合,在水浴加热条件下搅拌至粘稠状,所述偏钒酸铵溶液与钙钛矿型氧化物的混合比例为100mL:100g；(4)将粘稠状产物进行干燥处理,然后在550～650℃下焙烧2～5h。本发明的有益效果在于：既保证了催化剂的脱硝活性和稳定性,又降低了钒的使用量。(The invention discloses a preparation method of an SCR denitration catalyst with ultralow vanadium loading by taking perovskite type composite oxide as a carrier, relating to the technical field of denitration catalysts and comprising the following steps: (1) dissolving ammonium metavanadate in an oxalic acid solution, and fully stirring to completely dissolve the ammonium metavanadate to obtain an ammonium metavanadate solution; the concentration of ammonium metavanadate in the ammonium metavanadate solution is 2-6 g/L; (2) grinding the perovskite type composite oxide by using an agate mortar and then sieving; (3) mixing an ammonium metavanadate solution and a perovskite type composite oxide, and stirring to be viscous under the water bath heating condition, wherein the mixing ratio of the ammonium metavanadate solution to the perovskite type oxide is 100mL:100 g; (4) and drying the viscous product, and roasting at 550-650 ℃ for 2-5 h. The invention has the beneficial effects that: not only ensures the denitration activity and stability of the catalyst, but also reduces the usage amount of vanadium.)
1. A preparation method of an SCR denitration catalyst with ultralow vanadium load by taking perovskite type composite oxide as a carrier is characterized by comprising the following steps: the method comprises the following steps:
(1) dissolving ammonium metavanadate in an oxalic acid solution, and fully stirring to obtain an ammonium metavanadate solution; the concentration of ammonium metavanadate in the ammonium metavanadate solution is 2-6 g/L;
(2) grinding the perovskite type composite oxide by using an agate mortar, and sieving to prepare a catalyst carrier;
(3) mixing the ammonium metavanadate solution obtained in the step (1) with the perovskite type composite oxide obtained in the step (2), and stirring the mixture under the water bath heating condition until the mixture is sticky, wherein the mixing ratio of the ammonium metavanadate solution to the perovskite type oxide is 100mL:100 g;
(4) and (4) drying the viscous product obtained in the step (3), and roasting at 600-650 ℃ for 2-5 h.
2. The method for preparing the SCR denitration catalyst with the ultralow vanadium loading by using the perovskite type composite oxide as the carrier according to claim 1, is characterized in that: the concentration of the oxalic acid solution in the step (1) is 10-100 g/L.
3. The method for preparing the SCR denitration catalyst with the ultralow vanadium loading by using the perovskite type composite oxide as the carrier according to claim 1, is characterized in that: the perovskite type composite oxide in the step (2) comprises CaTiO3、BaTiO3、SrTiO3、LaCoO3、LaFeO3、LaNiO3。
4. The method of claim 3, wherein said step is performed in the presence of calcium and titaniumThe preparation method of the SCR denitration catalyst with ultralow vanadium loading and with the mineral composite oxide as the carrier is characterized by comprising the following steps of: the perovskite type composite oxide is CaTiO3。
5. The method for preparing the SCR denitration catalyst with the ultralow vanadium loading by using the perovskite type composite oxide as the carrier according to claim 1, is characterized in that: and (3) sieving with a 200-mesh sieve in the step (2).
6. The method for preparing the SCR denitration catalyst with the ultralow vanadium loading by using the perovskite type composite oxide as the carrier according to claim 1, is characterized in that: the temperature of the water bath heating in the step (3) is 65-90 ℃.
7. The method for preparing the SCR denitration catalyst with the ultralow vanadium loading by using the perovskite type composite oxide as the carrier according to claim 1, is characterized in that: in the step (4), the drying adopts a temperature programming drying mode, and the drying program is as follows: heating from room temperature to 90 deg.C at 5 deg.C/min and holding for 2h, and then heating to 10 deg.C at 5 deg.C/min and holding for 2 h.
8. An SCR denitration catalyst produced by the method of any one of claims 1 to 7.
Technical Field
The invention relates to the technical field of denitration catalysts, in particular to a preparation method of an SCR denitration catalyst with ultralow vanadium loading by taking perovskite type composite oxide as a carrier and a prepared catalyst.
Background
Nitrogen Oxides (NO) produced in flue gas of industrial kilnx) There are three types of (1): thermal, rapid and fuel types. For reducing NO in flue gasxConcentration, typically by spraying ammonia water inside the kiln to make NOxUnder the action of high temperature and NH3Conversion by reaction to N2I.e. the selective non-catalytic reduction technique (SNCR). However, the technology can only reduce about 50-70% of NO in the smokexThe emission requirement cannot be met for a common industrial kiln, so that the NO in the flue gas can be further reduced by using a Selective Catalytic Reduction (SCR) technology at the rear end of treatmentxThe concentration of (c).
The core of the SCR denitration technology is a denitration catalyst, and the existing commercial SCR denitration catalyst is mainly a vanadium-tungsten-titanium catalyst, and can meet the requirements of flue gas denitration in different temperature ranges of high, medium and low temperatures. The medium-low temperature denitration has higher requirement on the activity of the catalyst, and the high-temperature denitration has higher thermal stability on the catalyst. Titanium dioxide (TiO) can be generated in the vanadium-tungsten-titanium SCR denitration catalyst at high temperature2) Crystal phase transition of the carrier and agglomeration of the active components.
Perovskite-type oxide (ABO)3) The substance has direct catalytic decomposition effect on NO and the like, for example, a patent with the publication number of CN106492791A discloses a medium-low temperature denitration catalyst and a preparation method thereof, wherein the catalyst takes strontium-doped cerium-manganese perovskite type composite oxide and superfine titanium dioxide as carriers, and the prepared catalyst has the characteristics of low temperatureThe high activity is mainly attributed to Mn (having low-temperature denitration activity) in the strontium-doped cerium-manganese perovskite type composite oxide. But due to anatase type TiO2Starting at 610 ℃ towards rutile TiO2The conversion (Fuchunlin, Wei stannum, titanium dioxide crystal form conversion research, coating industry, 1999, 2: 28-30) is achieved, so that the catalyst which takes the strontium-doped cerium-manganese perovskite type composite oxide and the superfine titanium dioxide as the carriers and vanadium pentoxide as the main active components is only suitable for medium and low temperature denitration, but cannot keep higher thermal stability and denitration activity at high temperature (600-650 ℃).
Disclosure of Invention
The technical problem to be solved by the invention is to lack an SCR denitration catalyst with thermal stability and denitration activity at high temperature.
The invention solves the technical problems through the following technical means:
a preparation method of an SCR denitration catalyst with ultralow vanadium load by taking a perovskite type composite oxide as a carrier comprises the following steps:
(1) dissolving ammonium metavanadate in an oxalic acid solution, and fully stirring to obtain an ammonium metavanadate solution; the concentration of ammonium metavanadate in the ammonium metavanadate solution is 2-6 g/L;
(2) mixing perovskite type composite oxide (ABO)3) Grinding the mixture by using an agate mortar and sieving the mixture to prepare a catalyst carrier;
(3) mixing the ammonium metavanadate solution obtained in the step (1) with the catalyst carrier obtained in the step (2), and stirring the mixture under the water bath heating condition until the mixture is viscous, wherein the mixing ratio of the ammonium metavanadate solution to the perovskite type oxide is 100mL:100 g;
(4) and (4) drying the viscous product obtained in the step (3), and roasting at 600-650 ℃ for 2-5 h.
Has the advantages that: the present invention uses perovskite type composite oxide (ABO)3) The catalyst is a carrier, on one hand, the good thermal stability of the carrier is utilized to adjust the concentration of ammonium metavanadate and the proportion of the ammonium metavanadate and the perovskite type oxide, so that the thermal stability of the SCR denitration catalyst under the working condition of high temperature (600-650 ℃) is improved, and on the other hand, the titanium ore type is utilizedComposite oxide (ABO)3) The characteristic of directly catalyzing and decomposing NO at high temperature reduces the active component V2O5Amount of (2) and amount of (2)<0.5 percent. The method not only ensures the denitration activity and stability of the catalyst, but also reduces the use amount of vanadium.
Compared with the method adopting anatase type titanium dioxide as a carrier, the method can obviously improve the denitration activity of the catalyst.
Preferably, the concentration of the oxalic acid solution in the step (1) is 10-100 g/L.
Preferably, the perovskite-type composite oxide (ABO) in the step (2)3) Comprising CaTiO3、BaTiO3、SrTiO3、LaCoO3、LaFeO3、LaNiO3。
Preferably, the step (2) is performed by sieving with a 200-mesh sieve.
Preferably, the perovskite-type composite oxide is CaTiO3。
Preferably, the temperature of the water bath heating in the step (3) is 65-90 ℃.
Preferably, the drying in step (4) adopts a temperature-programmed drying method, and the drying procedure is as follows: heating from room temperature to 90 deg.C at 5 deg.C/min and holding for 2h, and then heating to 10 deg.C at 5 deg.C/min and holding for 2 h.
Has the advantages that: the purpose of low-speed temperature rise and stage heat preservation at the speed of 5 ℃/min is to prevent the active components from generating surface segregation in the drying process, so that the active components are not uniformly distributed on the carrier.
The invention also provides the SCR denitration catalyst prepared by the method.
Has the advantages that: the catalyst prepared by the invention has good thermal stability and denitration activity.
The invention has the advantages that: the present invention uses perovskite type composite oxide (ABO)3) The carrier is used, on one hand, the good thermal stability of the carrier is utilized to improve the thermal stability of the SCR denitration catalyst under the working condition of high temperature (600-650 ℃), on the other hand, the titanium ore type composite oxide (ABO) is utilized3) The characteristic of directly catalyzing and decomposing NO at high temperature reduces the active component V2O5Amount of (2) and amount of (2)<0.5 percent. The method not only ensures the denitration activity and stability of the catalyst, but also reduces the use amount of vanadium.
Compared with the method adopting anatase type titanium dioxide as a carrier, the method can obviously improve the denitration activity of the catalyst.
Drawings
FIG. 1 is a graph showing the results of the stability test of the catalysts of example 1 of the present invention and comparative example 1.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Test materials, reagents and the like used in the following examples are commercially available unless otherwise specified.
The specific techniques or conditions not specified in the examples can be performed according to the techniques or conditions described in the literature in the field or according to the product specification.
Example 1
The preparation method of the SCR denitration catalyst with ultralow vanadium load by taking the perovskite type composite oxide as the carrier specifically comprises the following steps:
(1) dissolving 0.6g of ammonium metavanadate in 100mL of oxalic acid solution with the concentration of 100g/L, and fully stirring to completely dissolve the ammonium metavanadate to obtain the ammonium metavanadate solution.
(2) Mixing the ammonium metavanadate solution obtained in the step (1) with 100g of CaTiO sieved by a 200-mesh sieve3And (4) uniformly mixing.
(3) And (3) stirring the mixture obtained in the step (2) under the heating condition of a water bath at 85 ℃ to evaporate water to be viscous.
(4) Drying the viscous product obtained in the step (3) in a forced air drying oven, wherein the drying procedure is as follows: heating from room temperature to 90 deg.C at 5 deg.C/min and holding for 2h, and then heating to 10 deg.C at 5 deg.C/min and holding for 2 h.
(5) Roasting the dried product obtained in the step (4) in a muffle furnace at 650 ℃, wherein the roasting time is 3h, and naturally cooling to obtain the perovskite type composite oxide CaTiO3Supported ultra low vanadium loaded SCR denitration catalyst wherein V2O5The loading of (b) was 0.46%.
Example 2
(1) Dissolving 0.5g of ammonium metavanadate in 100mL of oxalic acid solution with the concentration of 70g/L, and fully stirring to completely dissolve the ammonium metavanadate to obtain the ammonium metavanadate solution.
(2) Mixing the ammonium metavanadate solution obtained in the step (1) with 100g of BaTiO sieved by a 200-mesh sieve3And (4) uniformly mixing.
(3) And (3) stirring the mixture obtained in the step (2) under the heating condition of a water bath at 90 ℃ to evaporate water to be viscous.
(4) Drying the viscous product obtained in the step (3) in a forced air drying oven, wherein the drying procedure is as follows: heating from room temperature to 90 deg.C at 5 deg.C/min and holding for 2h, and then heating to 10 deg.C at 5 deg.C/min and holding for 2 h.
(5) Roasting the dried product obtained in the step (4) in a muffle furnace at 650 ℃, wherein the roasting time is 5h, and naturally cooling to obtain the perovskite type composite oxide BaTiO3Supported ultra low vanadium loaded SCR denitration catalyst wherein V2O5The loading capacity of the catalyst is 0.39 percent
Example 3
(1) Dissolving 0.3g of ammonium metavanadate in 100mL of oxalic acid solution with the concentration of 80g/L, and fully stirring to completely dissolve the ammonium metavanadate to obtain the ammonium metavanadate solution.
(2) Mixing the ammonium metavanadate solution obtained in the step (1) with 100g of LaFeO sieved by a 200-mesh sieve3And (4) uniformly mixing.
(3) And (3) stirring the mixture obtained in the step (2) under the water bath heating condition of 65 ℃ to evaporate water to be viscous.
(4) Drying the viscous product obtained in the step (3) in a forced air drying oven, wherein the drying procedure is as follows: heating from room temperature to 90 deg.C at 5 deg.C/min and holding for 2h, and then heating to 10 deg.C at 5 deg.C/min and holding for 2 h.
(5) Roasting the dried product obtained in the step (4) in a muffle furnace at 625 ℃, wherein the roasting time is 2h, and naturally cooling to obtain the perovskite type composite oxide LaFeO3Supported ultra low vanadium loaded SCR denitration catalyst wherein V2O5The loading of (b) was 0.23%.
Example 4
(1) Dissolving 0.4g of ammonium metavanadate in 100mL of oxalic acid solution with the concentration of 30g/L, and fully stirring to completely dissolve the ammonium metavanadate to obtain the ammonium metavanadate solution.
(2) Mixing the ammonium metavanadate solution obtained in the step (1) with 100g of LaCoO sieved by a 200-mesh sieve3And (4) uniformly mixing.
(3) And (3) stirring the mixture obtained in the step (2) under the water bath heating condition of 70 ℃ to evaporate water to be viscous.
(4) Drying the viscous product obtained in the step (3) in a forced air drying oven, wherein the drying procedure is as follows: heating from room temperature to 90 deg.C at 5 deg.C/min and holding for 2h, and then heating to 10 deg.C at 5 deg.C/min and holding for 2 h.
(5) Roasting the dried product obtained in the step (4) in a muffle furnace at 630 ℃ for 4h, and naturally cooling to obtain the perovskite type composite oxide LaCoO3Supported ultra low vanadium loaded SCR denitration catalyst wherein V2O5The amount of (B) was 0.31%.
Comparative example 1
This comparative example differs from example 1 in that: perovskite type composite oxide CaTiO3By substitution of anatase type TiO2。
Comparative example 2
This comparative example differs from example 2 in that: mixing perovskite type composite oxide BaTiO3By substitution of anatase type TiO2。
Comparative example 3
This comparative example differs from example 3 in that: the perovskite type composite oxide LaFeO3By replacement withAnatase type TiO2。
Comparative example 4
This comparative example differs from example 4 in that: the perovskite type composite oxide LaCoO3By substitution of anatase type TiO2。
Experimental data and analysis:
the denitration performance evaluation of the denitration catalysts in examples 1 to 4 and comparative examples 1 to 4 was performed under the following reaction conditions: NO concentration 2000ppm, NH3Concentration 2000ppm, 10 vol.% O2The others are Ar, and the space velocity is 20000h-1The reaction temperature was 650 ℃. The denitration performance is shown in Table 1. The results of the catalyst stability experiments for example 1 and comparative example 1 are shown in fig. 1.
TABLE 1 measurement results of denitration performance of catalyst
Item
Catalyst and process for preparing same
Denitration efficiency/%)
Example 1
V2O5/CaTiO3
89.43
Comparative example 1
V2O5/TiO2
70.23
Example 2
V2O5/BaTiO3
75.93
Comparative example 2
V2O5/TiO2
63.29
Example 3
V2O5/LaFeO3
47.24
Comparative example 3
V2O5/TiO2
35.27
Example 4
V2O5/LaCoO3
52.36
Comparative example 4
V2O5/TiO2
45.56
The test results showed that perovskite-type composite oxides (ABO) obtained in examples 1, 2, 3 and 4 of the present invention3) SCR denitration catalyst with ultralow vanadium load as carrier and anatase type TiO2Is a V of a carrier2O5/TiO2Compared with the denitration catalyst, the denitration catalyst has higher denitration activity at 650 ℃, and when the carrier is CaTiO3In this case, the denitration efficiency is the best. This shows that the denitration catalyst of the present invention has better adaptability to high temperature conditions.
The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
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