Honeycomb SCR (Selective Catalytic Reduction) denitration catalyst with supported inner wall surface

Abstract

The invention discloses an inner wall surface loaded honeycomb SCR denitration catalyst, and relates to the technical field of catalysts. The inner wall surface loaded honeycomb SCR denitration catalyst comprises a honeycomb carrier, the honeycomb carrier is provided with a plurality of honeycomb pore channels, and any honeycomb pore channel comprises a pore channel wall and a hollow channel; a surface layer and an inner layer are arranged on the wall of any pore channel; active components of the catalyst are loaded on the surface layer; or the active component of the catalyst is simultaneously loaded on the surface layer and the inner layer, and the concentration of the active component loaded on the surface layer is greater than that of the active component loaded on the inner layer. According to the present invention, the overall use amount of the active component can be effectively reduced, the SO2 oxidation side reaction can be reduced, the secondary pollution, the equipment blockage and other conditions can be avoided, the production cost can be easily saved, the production efficiency can be easily improved, and the product performance quality can be easily improved.

Description

Technical Field

[0001] The present application relates to the field of catalyst technology, and in particular to an inner wall surface-loaded honeycomb SCR denitration catalyst. Background Art

[0002] Existing homogeneous honeycomb SCR denitration catalysts are usually manufactured using an integral extrusion process, where the active components, catalyst carriers, and various auxiliary materials are uniformly mixed to form a slurry, which is then extruded and formed, and then dried and calcined to form the product. As the amount of active components increases, the difficulty of extruding the product increases, and it is not easy to extrude products with thinner walls, and the production qualification rate decreases, resulting in increased production costs; in addition, while catalyzing denitration, the active components of the SCR denitration catalyst will also catalyze the oxidation of SO2 in the flue gas to generate SO3. In order to pursue higher denitration performance, increasing the amount of active substances will lead to a significant increase in the SO2 oxidation rate, which in turn causes a sharp increase in the risk of catalyst ammonium sulfate poisoning and blockage of related equipment downstream of the catalyst.

[0003] There is also a method of producing a honeycomb SCR denitration catalyst using an impregnation process in the existing process, that is, first producing a carrier that does not contain (or contains very low) active components, and then impregnating the carrier into a solution containing active components. Due to the super hydrophilic properties of the honeycomb SCR denitration catalyst carrier, the solution will completely infiltrate the carrier in a short time, causing the entire inner wall of the honeycomb SCR denitration catalyst to be penetrated by the solution. Usually, the solution loading mass percentage of the carrier is 25-30%. In the subsequent drying and calcination processes, it is easy to cause the physical properties of the catalyst (for example: compressive resistance) to decrease, and the amount of active substance required for the impregnation process is basically equivalent to that of the homogeneous honeycomb SCR denitration catalyst.

[0004] In addition, there is also a carrier coating process for producing honeycomb SCR denitration catalysts, which prepares a relatively viscous active component slurry and directly coats it on the surface of the inner wall of the honeycomb carrier channel. The advantage of this process is that the process is relatively mature, but the disadvantage is that the cost of the process raw materials is high, the commonly used carrier "cordierite" is expensive, and the coating layer has a greater risk of peeling off. Summary of the invention

[0005] The purpose of the present application is to provide an inner wall surface loaded honeycomb SCR denitrification catalyst, wherein the active components are distributed on the inner wall surface of the honeycomb carrier pores, and the solid interior of the carrier contains no or very little active components, which can effectively reduce the overall dosage of the active components, while reducing the occurrence of SO2 oxidation side reactions, avoiding secondary pollution and equipment blockage, etc., which helps to save production costs, improve production efficiency, and enhance product performance quality.

[0006] The technical solution of this application is as follows:

[0007] The embodiment of the present application provides an inner wall surface supported honeycomb SCR denitration catalyst, which includes a honeycomb carrier, the honeycomb carrier is provided with a plurality of honeycomb channels, any of the honeycomb channels includes a channel wall and a hollow channel; any of the channel walls is provided with a surface layer and an inner layer, the surface layer is provided on the surface of the channel wall and exposed to the hollow interior of the hollow channel, and the inner layer is located in the solid interior of the channel wall;

[0008] The active components of the catalyst are loaded on the surface layer;

[0009] Alternatively, the active components of the catalyst are simultaneously loaded on the surface layer and the inner layer, and the concentration of the active components loaded on the surface layer is greater than the concentration of the active components loaded on the inner layer.

[0010] Compared with the prior art, the embodiments of the present application have at least the following advantages or beneficial effects:

[0011] In view of the above aspects, the embodiment of the present application provides an inner wall surface loaded honeycomb SCR denitration catalyst, whose active components are distributed on the inner wall surface of the honeycomb carrier channel, and the solid interior of the carrier does not contain or contains very little active components. Since the denitration reaction is a fast reaction (it is easy to reach DeNOx>80%), the denitration reaction process usually only reacts on the surface of the catalyst; on the contrary, since the SO2 oxidation reaction is a slow reaction (usually SO2 / SO3<5%), it will occur in the entire catalyst body phase; and in the present application scheme, the active components of the catalyst are loaded on the surface, and the solid interior of the carrier does not contain or contains very little active components; therefore, the active components loaded on the surface can fully carry out a faster denitration reaction, so that the active components loaded on the surface can quickly play their role, and the inner layer does not contain or contains only a small amount of active components, so that the occurrence of the slower SO2 oxidation side reaction can be effectively reduced, which can not only ensure a good denitration effect, but also greatly reduce the SO2 / SO3 conversion rate, thereby avoiding secondary pollution, catalyst poisoning due to sulfur, and equipment blockage, etc., which helps to extend the life of the equipment and product catalyst. At the same time, loading all or most of the active components only on the surface of the honeycomb channel wall can effectively reduce the amount of active components used, thereby reducing raw material costs, improving production efficiency, and ensuring product quality.

[0012] Furthermore, in some embodiments of the present application, the thickness of the surface layer is 10 to 500 μm.

[0013] In the above embodiment, the surface thickness (i.e. the penetration depth of the active components loaded) can be adjusted according to actual needs. The active component content is adjustable in the shallow surface layer of the carrier, which can greatly improve the denitration effect and achieve higher nitrogen oxide removal efficiency compared with traditional denitration catalysts.

[0014] Furthermore, in some embodiments of the present application, an inner surface layer is provided on the side of the surface layer close to the inner layer, and the inner surface layer is located between the inner layer and the surface layer; the inner surface layer is also loaded with active components.

[0015] Furthermore, in some embodiments of the present application, the inner surface layer and the surface layer are loaded with the same or several active components;

[0016] Alternatively, the inner layer and the surface layer are loaded with different active components.

[0017] In the above embodiments, different catalytic reaction effects can be achieved by loading active components with different functions on the surface layer and the inner surface layer respectively.

[0018] Furthermore, in some embodiments of the present application, the honeycomb carrier is provided with a plurality of loading areas, and different loading areas are loaded with the same or different active components.

[0019] Furthermore, in some embodiments of the present application, the plurality of load areas are distributed along a horizontal direction of a cross section of the honeycomb carrier and / or a length direction of the honeycomb carrier.

[0020] In the above embodiments, active components or active component combinations with different functions can be loaded in different loading areas on the same honeycomb carrier, so as to realize a variety of combined catalytic production functions, for example, a layer of catalyst can simultaneously achieve the combined effects of denitrification, demercurization, dedioxin, and deVOC.

[0021] Furthermore, in some embodiments of the present application, the active components of the catalyst are loaded on the honeycomb carrier in a permeation manner.

[0022] In the above embodiments, the active components are loaded on the honeycomb carrier by penetrating into the interior rather than coating in layers, thereby avoiding the coating from falling off and achieving good stability.

[0023] Furthermore, in some embodiments of the present application, the active component of the above-mentioned catalyst is any one or more of a vanadium-containing precursor, a tungsten-containing precursor, and a transition metal oxide.

[0024] Furthermore, in some embodiments of the present application, the vanadium-containing precursor includes ammonium metavanadate and vanadium pentoxide; the tungsten-containing precursor includes ammonium metatungstate and ammonium paratungstate; and the transition metal oxide includes copper oxide, manganese oxide and cerium oxide.

[0025] Furthermore, in some embodiments of the present application, the inner wall surface supported honeycomb SCR denitration catalyst is prepared by the following method:

[0026] Preparation of carrier: nano titanium dioxide powder, alkali-free glass fiber, polyethylene oxide, methyl hydroxypropyl cellulose, ammonia water, and deionized water are mixed evenly, then kneaded and extruded to form a honeycomb structure, and dried to obtain a honeycomb carrier;

[0027] Preparation of active components: taking any one or more of a vanadium-containing precursor, a tungsten-containing precursor, and a transition metal oxide, and preparing an active component solution;

[0028] Loading: using atomization loading equipment to spray the prepared active component solution into the honeycomb channels of the honeycomb carrier, so that the active component is loaded on the surface layer of the channel wall; or loaded on the surface layer and inner layer of the channel wall at the same time, and the concentration of the active component loaded on the surface layer is greater than the concentration of the active component loaded and the inner layer;

[0029] Drying and calcining: The honeycomb carrier loaded with active components is dried and calcined to obtain the product catalyst.

[0030] In the above embodiment, no active components are contained in the preparation process of the carrier, which can greatly reduce the difficulty of extrusion molding of the honeycomb carrier, especially the thin-walled honeycomb carrier, and improve the product qualification rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 This is a schematic diagram of the cross-sectional structure of a honeycomb carrier in an embodiment of the present application;

[0033] Figure 2 This is a schematic diagram of the load area distribution along the horizontal direction of the cross section of the honeycomb carrier in the embodiment of the present application;

[0034] Figure 3 Schematic diagram of the load area distribution along the length direction of the honeycomb carrier in the embodiment of the present application.

[0035] Figure numerals: 1-honeycomb channel, 2-channel wall, 3-hollow channel, 4-surface layer, 5-inner surface layer, 6-inner layer. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to the conventional conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0037] In the description of the embodiments of the present application, it should be noted that if the terms "horizontal", "inside", "outside", etc. appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the accompanying drawings, or is the orientation or position relationship in which the product of the application is usually placed when used. It is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0038] In the description of the embodiments of the present application, "plurality" means at least 2.

[0039] It should be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "includes..." do not exclude the existence of other identical elements in the process, method, article or device including its elements.

[0040] At the same time, the embodiments in this application and the features in the embodiments may be combined with each other without conflict.

[0041] The features and performance of the present application are further described in detail below in conjunction with the embodiments.

[0042] Example 1

[0043] This embodiment provides an inner wall surface supported honeycomb SCR denitration catalyst;

[0044] like Figure 1 to Figure 3 As shown, it includes a honeycomb carrier, the honeycomb carrier is provided with a plurality of honeycomb channels 1, any of the honeycomb channels 1 includes a channel wall 2 and a hollow channel 3; any of the channel walls 2 is provided with a surface layer 4 and an inner layer 6, the surface layer 4 is provided on the surface of the channel wall 2 and exposed in the hollow channel 3, and the inner layer 6 is located in the solid interior of the channel wall 2;

[0045] The active components of the catalyst are loaded on the surface layer 4;

[0046] Alternatively, the active components of the catalyst are simultaneously loaded on the surface layer 4 and the inner layer 6 , and the concentration of the active components loaded on the surface layer 4 is greater than the concentration of the active components loaded on the inner layer 6 .

[0047] Furthermore, the thickness of the surface layer 4 is 10 to 500 μm.

[0048] Furthermore, an inner surface layer 5 is further provided on a side of the surface layer 4 close to the inner layer 6 , and the inner surface layer 5 is located between the inner layer 6 and the surface layer 4 ; the inner surface layer 5 is also loaded with active components.

[0049] Furthermore, the inner surface layer 5 and the surface layer 4 are loaded with the same or several active components;

[0050] Alternatively, the inner layer 5 and the surface layer 4 are loaded with different active components.

[0051] like Figure 2-3 As shown, further, the honeycomb carrier is provided with a plurality of loading areas, and different loading areas are loaded with the same or different active components.

[0052] Furthermore, the plurality of load areas are arranged along the horizontal direction of the cross section of the honeycomb carrier (eg Figure 2 As shown, the entire rectangular pattern is a cross section of a honeycomb carrier, wherein the multiple squares represent honeycomb channels 1, and different color blocks represent different load areas) and / or the length direction of the honeycomb carrier (such as Figure 3 As shown, the entire strip structure pattern is a honeycomb carrier, and different color blocks represent different load areas) distribution.

[0053] Specifically, a spray loading device may be used, using at least one spray head or other spraying component, to spray different active components on different loading areas separately or simultaneously, so that different active components are separately infiltrated and loaded on different carrier loading areas.

[0054] Furthermore, the active components of the catalyst are loaded on the honeycomb carrier in a permeation manner.

[0055] Furthermore, the active component of the above catalyst is any one or more of a vanadium-containing precursor, a tungsten-containing precursor, and a transition metal oxide.

[0056] Example 2

[0057] This embodiment provides an inner wall surface supported honeycomb SCR denitration catalyst, the product catalyst structure of which is designed based on Example 1; it is prepared by the following method:

[0058] Preparation of carrier: by mass percentage, 65% of nano titanium dioxide powder, 6% of alkali-free glass fiber, 1.2% of polyethylene oxide, 0.6% of methyl hydroxypropyl cellulose, 3.2% of ammonia water, and 24% of deionized water are mixed evenly, then kneaded and extruded through an extruder to form a honeycomb structure, and dried to obtain a honeycomb carrier; the side length is 150 mm×150 mm, the holes are 16×16, the wall thickness is 1.0 mm, and the length is 1000 mm;

[0059] Preparation of active components: Set the surface vanadium content to 3% and the tungsten content to 5% after loading, prepare a mixed solution of ammonium metavanadate and ammonium metatungstate as the active component solution for standby use;

[0060] Loading: Load the prepared active component solution into the liquid storage tank of the atomization loading equipment, adjust the atomization pressure, and spray the active component solution into the honeycomb channels of the honeycomb carrier so that the active component solution penetrates the surface layer of the channel wall;

[0061] Drying and calcining: The honeycomb carrier loaded with active components is dried and calcined to obtain the product catalyst.

[0062] Example 3

[0063] This embodiment is based on Embodiment 2, and differs from Embodiment 2 in that in the loading step, the amount of the active component solution sprayed into the honeycomb pores is tripled.

[0064] Example 4

[0065] This embodiment is based on Embodiment 2, and differs from Embodiment 2 in that: in the step of preparing the active component, the concentration of the ammonium metavanadate solution prepared is half of the concentration of the ammonium vanadate solution in Embodiment 2.

[0066] Comparative Example 1

[0067] A homogeneous honeycomb SCR denitration catalyst is prepared according to conventional technology, and the target product catalyst has a vanadium content of 3% and a tungsten content of 5%;

[0068] The preparation method is as follows:

[0069] By mass percentage, 65% of nano titanium dioxide powder, 6% of alkali-free glass fiber, 1.2% of polyethylene oxide, 0.6% of methyl hydroxypropyl cellulose, 2.7% of ammonia water, 8.5% of ammonium metavanadate solution, 6% of ammonium metatungstate solution, and 10% of water are mixed evenly, kneaded and formed into a honeycomb structure by an extruder, and after drying and calcination, a homogeneous honeycomb SCR denitration catalyst with a side length of 150mm×150mm, 16×16 holes, a wall thickness of 1.0mm, and a length of 1000mm is made.

[0070] Comparative Example 2

[0071] This comparative example is based on comparative example 1, and the difference from comparative example 1 is:

[0072] The target product catalyst has a vanadium content of 0.8% and a tungsten content of 5%. An ammonium metavanadate solution and an ammonium metatungstate solution are prepared, and the other raw material components are adjusted accordingly.

[0073] Comparative Example 3

[0074] The honeycomb SCR denitration catalyst is prepared by impregnation process, and the target product catalyst has a vanadium content of 3% and a tungsten content of 5%;

[0075] The preparation method of the honeycomb carrier is the same as that of Example 2, and the components of the active component solution are ammonium metavanadate and ammonium metatungstate;

[0076] During preparation, the honeycomb carrier is vertically immersed in an excess volume of active component solution, with the liquid level exceeding the upper surface of the carrier by more than 100 mm, for 30 minutes, during which the mixed solution is ensured to flow up and down inside;

[0077] It is then dried and calcined to obtain the product catalyst.

[0078] Test Example 1

[0079] Process test:

[0080] The relevant data of each production process in Examples 2 to 4 and Comparative Examples 1 to 3 were statistically analyzed, and the specific items and results are shown in Table 1:

[0081] Table 1

[0082]

[0083] As shown in Table 1, the carrier extrusion efficiency of the impregnation process of the embodiment of the present application and the comparative example 3 is relatively high. The homogeneous catalyst solution of the comparative example 1 leads to a deviation in the carrier extrusion efficiency due to the presence of relatively high active components in the raw materials, and the comparative example 2 improves the extrusion efficiency due to the reduction of the active component content in the raw materials;

[0084] The drying qualified rate of the product of the embodiment of the present application is significantly higher than that of the conventional homogeneous catalyst production scheme in Comparative Example 1, and slightly higher than that of the impregnation scheme in Comparative Example 3;

[0085] The calcination qualified rate of the product in the examples of the present application is significantly higher than that of the traditional homogeneous catalyst production scheme in Comparative Example 1, and slightly higher than that of the impregnation scheme in Comparative Example 3.

[0086] Test Example 2

[0087] Product testing:

[0088] The active component content of the carrier part of the product obtained in the embodiment and the comparative example was tested:

[0089] Test of active substance content of carrier: The carrier part of each group of products was cut and sampled to obtain a circular sheet sample with a diameter of 5 cm, and the cross-section was polished, taking care not to wear the surface, and then the active substance content was tested using a wavelength dispersive XRF instrument to obtain the active substance content of the carrier surface, as shown in Table 2;

[0090] Test of average active substance content of carrier: The carrier part of each group of products was sampled, ground and tableted, and then the active substance content was tested using a wavelength dispersive XRF instrument to obtain the average active substance content of the carrier, as shown in Table 2:

[0091] Table 2

[0092]

[0093] It can be seen that the carrier surfaces and interiors of the products of Example 2, Example 3, Example 4 and Comparative Example 3 do not contain active substances.

[0094] The active component content of the product catalyst obtained in the embodiment and the comparative example was tested:

[0095] Test of active substance content on catalyst surface: The catalyst of each group of products was cut and sampled to obtain a circular sheet sample with a diameter of 5 cm, and the cross-section was polished, taking care not to wear the surface, and then the active substance content was detected using a wavelength dispersive XRF instrument to obtain the active substance content on the catalyst surface (the pore wall of the honeycomb pores), as shown in Table 3;

[0096] Test of average active substance content of catalyst: The catalysts of each group of products were sampled, ground and pressed into tablets, and then the active substance content was tested using a wavelength dispersive XRF instrument to obtain the average active substance content of the catalyst, as shown in Table 3:

[0097] Table 3

[0098]

[0099]

[0100] Catalytic performance test of product catalyst samples: The product catalysts of the examples and comparative examples were cut, and samples with 2×2 holes and a length of 260 mm were taken. The denitrification performance and SO2 / SO3 conversion rate were tested under the flue gas conditions shown in Table 4 (NH3 was not added when testing the SO2 / SO3 conversion rate). The test results are shown in Table 5.

[0101] Table 4

[0102] Flue gas parameters unit Target value <![CDATA[O2 content]]> vol.%,dry 2 <![CDATA[H2O content]]> vol.%,wet 10 NO content vpm,STPdry 480 <![CDATA[NH3 content]]> vpm,STPdry 480 <![CDATA[SO2 content]]> vpm,STPdry 480 Total flue gas volume L / h,dry 918 temperature ℃ 380

[0103] Table 5

[0104]

[0105] From the above test results, we can see that:

[0106] As shown in Table 3, the content of active substances on the surface of the pore wall of the catalyst of Example 2 of the present application is basically equivalent to the content of active substances on the surface of the inner wall of the pore of the homogeneous honeycomb catalyst (Comparative Example 1); but the average active component content of the catalyst of Example 2 is significantly lower than that of the homogeneous honeycomb catalyst Comparative Example 1; It can be seen from Table 5 that the denitration efficiency of the two is basically equivalent, but the SO2 / SO3 conversion rate of Comparative Example 1 is about 3 times that of Example 1, which means that: when the content of surface active substances is basically equivalent, the catalyst provided in the embodiment of the present application has equivalent denitration performance to the traditional homogeneous SCR denitration catalyst, but the SO2 / SO3 conversion rate of the catalyst provided in the present application is much lower than that of the traditional homogeneous SCR denitration catalyst, and the amount of active components (vanadium and tungsten) is greatly reduced.

[0107] As shown in Table 3, the content of active substances on the pore wall surface of the catalyst of Example 2 of the present application is significantly higher than that of the pore inner wall surface of the homogeneous honeycomb catalyst comparative example 2; while the average active component content of the catalyst of Example 2 is lower than that of the homogeneous honeycomb catalyst comparative example 2; as can be seen from Table 4, the SO2 / SO3 conversion rates of the two are basically the same, but the denitration performance of Example 2 is much higher than that of Comparative Example 2. Description: Compared with the traditional homogeneous honeycomb catalyst, the inner wall surface loaded honeycomb catalyst of the present invention can have higher denitration performance under the condition of the same SO2 / SO3 conversion rate level.

[0108] In comparison between Example 2 and Example 3, the spray loading amount of the active component solution in the latter has been tripled, and the content of the active substance on the surface of the pore wall has not been significantly increased. Combining Table 3 and Table 5, it can be seen that there is no significant difference in the denitration performance of the two. However, the increase in the active substance loading has significantly increased the average active component content of the catalyst, and the corresponding SO2 / SO3 conversion rate of Example 2 in Table 5 has also increased significantly, indicating that the SO2 / SO3 conversion rate of the inner wall surface-loaded honeycomb SCR denitration catalyst of the present invention will increase with the increase in the active substance loading.

[0109] Comparing Example 2 and Example 4, the loading solution concentration of Example 4 is only 50% of that of Example 2. As can be seen from Table 3, the active substance content on the pore wall surface and the average active substance content of the latter product catalyst are both reduced. Correspondingly, as can be seen from Table 5, the denitration efficiency and SO2 / SO3 conversion rate of Example 4 are also reduced compared with Example 2.

[0110] Comparing Example 2 and Comparative Example 3, although the denitration efficiency, production efficiency and qualified rate of the impregnation process (Comparative Example 3) are basically equivalent to those of Example 1 of the present invention, it can be seen from Table 3 that the average active substance content of Comparative Example 3 is relatively higher. At the same time, it can be seen from Table 5 that the SO2 / SO3 conversion rate of Comparative Example 3 is also higher.

[0111] In summary, the embodiment of the present application provides an inner wall surface loaded honeycomb SCR denitration catalyst, whose active components are distributed on the inner wall surface of the honeycomb carrier channel, and the solid interior of the carrier does not contain or contains very little active components. Since the denitration reaction is a fast reaction (it is easy to reach DeNOx>80%), the denitration reaction process usually only reacts on the surface of the catalyst; on the contrary, since the SO2 oxidation reaction is a slow reaction (usually SO2 / SO3<5%), it will occur in the entire catalyst body phase; and in the present application scheme, the active components of the catalyst are loaded on the surface, and the solid interior of the carrier does not contain or contains very little active components; therefore, the active components loaded on the surface can fully carry out a faster denitration reaction, so that the active components loaded on the surface can quickly play their role, and the inner layer does not contain or contains only a small amount of active components, so that the slow SO2 oxidation side reaction can be effectively reduced, which can not only ensure a good denitration effect, but also greatly reduce the SO2 / SO3 conversion rate, thereby avoiding secondary pollution, catalyst poisoning due to sulfur, and equipment blockage, etc., which helps to extend the life of the equipment and product catalyst. At the same time, loading all or most of the active components only on the surface of the honeycomb channel wall can effectively reduce the amount of active components used, thereby reducing raw material costs, improving production efficiency, and ensuring product quality.

[0112] The embodiments described above are part of the embodiments of the present application, rather than all of the embodiments. The detailed description of the embodiments of the present application is not intended to limit the scope of the present application for protection, but merely represents the selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present application.

Claims

1. An inner wall surface supported honeycomb SCR denitration catalyst, characterized in that: It comprises a honeycomb carrier, the honeycomb carrier is provided with a plurality of honeycomb channels, any one of the honeycomb channels comprises a channel wall and a hollow channel; any one of the channel walls is provided with a surface layer and an inner layer, the surface layer is provided on the surface of the channel wall and exposed to the hollow interior of the hollow channel, and the inner layer is located in the solid interior of the channel wall; The active components of the catalyst are loaded on the surface layer; Alternatively, the active components of the catalyst are loaded on the surface layer and the inner layer at the same time, and the concentration of the active components loaded on the surface layer is greater than the concentration of the active components loaded on the inner layer.

2. The inner wall surface supported honeycomb SCR denitration catalyst according to claim 1, characterized in that: The thickness of the surface layer is 10 to 500 μm.

3. The inner wall surface supported honeycomb SCR denitration catalyst according to claim 1, characterized in that: The honeycomb carrier is provided with a plurality of loading areas, and different loading areas are loaded with the same or different active components.

4. The inner wall surface supported honeycomb SCR denitration catalyst according to claim 3, characterized in that: The plurality of load areas are distributed along the horizontal direction of the cross section of the honeycomb carrier and / or the length direction of the honeycomb carrier.

5. The inner wall surface supported honeycomb SCR denitration catalyst according to any one of claims 1 to 4, characterized in that: The active components of the catalyst are loaded on the honeycomb carrier in a permeating manner.

6. The inner wall surface supported honeycomb SCR denitration catalyst according to any one of claims 1 to 4, characterized in that: The active components of the catalyst are any one or more of a vanadium-containing precursor, a tungsten-containing precursor, and a transition metal oxide.

7. The inner wall surface supported honeycomb SCR denitration catalyst according to claim 6, characterized in that: The vanadium-containing precursor includes ammonium metavanadate and vanadium pentoxide; the tungsten-containing precursor includes ammonium metatungstate and ammonium paratungstate; and the transition metal oxide includes copper oxide, manganese oxide and cerium oxide.

8. A method for preparing an inner wall surface supported honeycomb SCR denitration catalyst according to any one of claims 1 to 7, characterized in that: It includes the following steps: Preparation of carrier: nano titanium dioxide powder, alkali-free glass fiber, polyethylene oxide, methyl hydroxypropyl cellulose, ammonia water, and deionized water are mixed evenly, then kneaded and extruded to form a honeycomb structure, and dried to obtain a honeycomb carrier; Preparation of active components: taking any one or more of a vanadium-containing precursor, a tungsten-containing precursor, and a transition metal oxide, and preparing an active component solution; Loading: using atomization loading equipment to spray the prepared active component solution into the honeycomb channels of the honeycomb carrier, so that the active component is loaded on the surface layer of the channel wall; or loaded on the surface layer and inner layer of the channel wall at the same time, and the concentration of the active component loaded on the surface layer is greater than the concentration of the active component loaded and the inner layer; Drying and calcining: The honeycomb carrier loaded with active components is dried and calcined to obtain the product catalyst.

Images