Background
The denitration of the flue gas of the coal-fired boiler mainly adopts a selective catalytic reduction technology (SCR technology for short), the core of the SCR technology is a denitration catalyst, and the operation condition of the denitration catalyst is closely related to the denitration effect.
The operation environment of the SCR catalyst is severe: the operation temperature is generally 270-420 ℃, the fly ash content is generally 5-90 g/Nm3, the uniformity of a flue gas velocity field is poor, and the deviation of a flue gas incident angle is large; high temperature, high velocity and fly ash containing flue gas can cause attrition to the catalyst, manifested by reduced catalyst wall thickness, perforation of the monomer, collapse of the module, etc.
The diameter of a honeycomb catalyst pore channel is small, generally 6-9 mm, and partial pore channels are blocked after the honeycomb catalyst is operated for a period of time. The available pore channels of the catalyst are reduced, the flow rate of flue gas in the residual pore channels is accelerated, and the efficiency of the catalyst is reduced. In order to relieve the blockage condition, a steam soot blower is often adopted for blowing, and steam with certain pressure and temperature is utilized to perform reciprocating blowing perpendicular to the windward side of the catalyst. The steam blowing device blows out steam with high pressure and high speed, and the catalyst is abraded while blowing deposited ash.
The denitration reactor has a narrow internal space, and the worn catalyst module is difficult to repair and develop. In the repairing process, generally, a module frame is cut by a cutting machine, the damaged catalyst unit bodies are taken out one by one, then new catalyst units are sequentially put in, and then the frame is welded. Because the number of catalyst monomers in the module is large, the mechanical strength is low, and the problems of high damage rate, untight sealing, long time consumption and the like exist in the replacement process. In view of the above, most enterprises adopt methods of abandoning repair of worn catalyst modules, scrapping all catalyst modules, and replacing new catalyst modules. Therefore, it is important to improve the abrasion resistance of the catalyst module and to enable easy repair when abrasion occurs.
Disclosure of Invention
The utility model aims at providing a SCR catalyst structure, especially an easy prosthetic SCR catalyst structure resistance to wears.
In order to achieve the above purpose, the utility model adopts the technical scheme that:
an SCR catalyst structure comprises an outer frame, a plurality of catalyst modules arranged in the outer frame,
the top of the outer frame is provided with an upper fixed frame and a detachable frame, the upper fixed frame is provided with a mouth part for replacing the catalyst module, and the detachable frame is connected with the mouth part of the upper fixed frame;
the catalyst module comprises an outer shell and a catalyst unit body arranged in the outer shell, wherein the top of the outer shell is provided with an opening, and the top of the catalyst unit body covers a cover body with an opening.
Preferably, the catalyst module further includes a sealing buffer layer wound around the outer circumferential surface of the catalyst unit body.
Further preferably, the sealing buffer layer is ceramic fiber cotton.
Preferably, the top of the outer shell is provided with a hanging hole.
Preferably, the periphery of the outer shell is sealed, and a support with a hollow part is formed at the bottom of the outer shell.
Preferably, the opening position of the cover body is consistent with the opening position of the catalyst monomer.
Preferably, the outer shell and the cover body are made of metal materials.
Preferably, the outer frame further comprises a lower fixing frame and side guard plates located on the periphery, and the side guard plates connect the upper fixing frame and the lower fixing frame and seal the periphery.
Preferably, the side guard plate comprises two oppositely arranged first side guard plates and two oppositely arranged second side guard plates, and one side of each first side guard plate is connected with one side of each second side guard plate.
Preferably, the outer frame is made of metal.
Because of the application of the technical scheme, compared with the prior art, the utility model has the following advantages:
1. the catalyst unit bodies can be supported and protected through the outer shell of the catalyst module, the capability of resisting smoke and side scouring is enhanced, and large-area collapse is not easy to happen when abrasion occurs; the mechanical impact resistance of the catalyst monomer is enhanced, and the damage caused by transportation and installation is reduced;
2. the fly ash abrasion resistance and the steam front blowing resistance of the catalyst module are greatly improved through the cover body of the catalyst module;
3. the catalyst module is flexible in arrangement, can be compatible and mixed with a common module, and can be replaced in a severely worn area;
4. the catalyst module is easy to repair, a catalyst installation door does not need to be opened, the whole catalyst module does not need to be hoisted, and the catalyst module can realize in-situ repair in a limited space of the reactor;
5. the catalyst module can be replaced for multiple times, is convenient and quick, saves time and labor, and is particularly suitable for a reactor with complex operation conditions, poor optimization effect of a flue gas flow field and serious catalyst abrasion.
Detailed Description
The technical solution of the present invention will be described clearly and completely with reference to the accompanying drawings, and obviously, the described embodiments are some, but not all embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.
In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplification of description, but do 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 thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.
An SCR catalyst structure as shown in fig. 1 comprises an outer frame, a plurality of catalyst modules 2 disposed within the outer frame. Specifically, the method comprises the following steps:
the outer frame comprises an upper fixed frame 10, a detachable frame 11, a lower fixed frame 12 and side guard plates positioned on the periphery, wherein the side guard plates are used for connecting the upper fixed frame 10 and the lower fixed frame 11 and sealing the periphery. In this embodiment: the side guard plate comprises two oppositely arranged first side guard plates 130 and two oppositely arranged second side guard plates 131, wherein one side of each first side guard plate 130 is connected with one side of each second side guard plate 131, and a square outer frame is enclosed. The upper fixing frame 10 has a mouth 100 for replacing the catalyst module 2, the detachable frame 11 is connected to the mouth 100 of the upper fixing frame 10, and the connection manner of the upper fixing frame 10 and the detachable frame 11 may be bolt connection, welding, snap connection, bundling connection, etc., as shown in fig. 2.
As shown in fig. 3-8: the catalyst module 2 includes an outer case 20, a catalyst unit body 21 disposed in the outer case 20, and a seal buffer layer 22 wound around an outer circumferential surface of the catalyst unit body 21. Wherein:
the periphery of the outer shell 20 is closed, the top of the outer shell 20 is provided with an opening, and the bottom of the outer shell 20 is provided with a hollowed support 200, such as a cross-shaped support shown in fig. 5; the top of the outer casing 20 is provided with a hanging hole 201. The outer shell 20 is made of metal, and can provide support and protection for the catalyst unit body 21, and enhance the capability of resisting the lateral erosion of smoke.
The number of catalyst units in each catalyst unit cell 21 may be 2 x 2, 1 x 3, 2 x 3, 1 x 4, 2 x 4, 1 x 6, etc., and may be adjusted according to the length, volume, weight, etc. of the catalyst unit cell 21. The sealing buffer layer 22 adopts ceramic fiber cotton.
The top (windward side) of the catalyst unit body 21 is covered with a cover 23 having an opening. The cover body 23 can be made of carbon steel, stainless steel, aluminum alloy and the like, holes are formed in a punching mode or a laser cutting mode, and the hole of the cover body 23 is consistent with the hole of the corresponding catalyst monomer, so that the anti-abrasion effect is optimized, and the anti-abrasion performance of the catalyst is improved.
When assembling the catalyst module:
firstly, a catalyst module 2 is manufactured, a sealing buffer layer 22 is wound on the side surface of a catalyst unit body 21 (formed by catalyst monomers), the catalyst unit body 21 is sequentially arranged in an outer shell 20, after the catalyst unit body 21 is arranged in the outer shell 20, a cover body 23 is covered on the windward side of the catalyst unit body 21, and a binder is coated for fixing, so that the cover body 23 is ensured to be tightly attached to the top end of the catalyst unit body 21.
After the catalyst modules 2 are manufactured, outer frame assembly is started, the upper fixing frame 10, the lower fixing frame 12 and part of the side protection plates are connected through bolts, then the catalyst modules 2 are placed into the outer frame according to a certain arrangement sequence, the catalyst modules 2 are required to be arranged tightly, after the catalyst modules are installed, the rest side protection plates are covered, the catalyst modules are fixed through the bolts, and finally the detachable frame 11 is connected with the upper fixing frame 10.
And when the catalyst module 2 is abraded in the denitration reactor and cannot meet the requirement of continuous use, the catalyst module is repaired and replaced.
When the catalyst module is replaced:
the detachable frame 11 is opened to be connected with the upper fixed frame 10, the detachable frame 11 is detached, the waste catalyst modules are sequentially taken out through the lifting holes 201, new catalyst modules are sequentially put in, the catalyst modules can be sequentially moved to appropriate positions after being put in, the detachable frame 11 is restored after the last catalyst module is inserted, and the repairing work of the catalyst modules is completed.
The first embodiment is as follows:
the catalyst module 2 had dimensions of 1930 x 970 x 1150mm, the catalyst was a honeycomb catalyst, having dimensions of 150 x 860mm, the number of cells was 18 cells, and the pitch was 8.2 mm. The outer frame is formed by welding Q235 flat steel, the size of the detachable frame 11 is 450 x 950 x 50mm, and the side guard plates are Q235 steel plates with the thickness of 4 mm.
The catalyst unit bodies 21 are arranged in a mode of 2 x 2, the outer shell 20 is made of stainless steel plates, the welding mode is argon tungsten-arc welding, the distance between the hanging holes 201 and the top is 10cm, and the aperture is 8 mm.
And a sealing buffer layer 22 made of ceramic fiber cotton is arranged between the catalyst monomers and used for sealing and buffering external force impact. The top of the catalyst unit body 21 is sleeved with a cover body 23, the cover body 23 is made of stainless steel, holes are 18 x 18 holes through laser cutting, the pitch is 8.2mm, and a small amount of glass cement is coated between the cover body 23 and the catalyst unit body 21 for fixing.
When assembling: the upper and lower fixed plate frames 10 and 12 are connected with a long side guard plate 130 and a short side guard plate 131, the connection is bolted connection, the catalyst and the module 2 are sequentially placed into the outer frame according to the arrangement mode 3 x 6, then the other two side guard plates are covered and fixed by bolts, and finally the detachable frame 11 is installed and connected with the upper fixed frame 10 by bolts.
The assembled catalyst is installed and put into use in the denitration reactor, and because the uniformity of a flue gas velocity field in the reactor is poor, after 20000 operation, the abrasion is generated at the position close to the denitration central line on the side of the boiler in the finished reactor, and the abrasion length of a catalyst monomer exceeds 5cm, so that the catalyst needs to be repaired.
During repair: the fastening bolts are unscrewed, the detachable frame 11 is detached, the catalyst module 2 facing the detachable frame 11 is lifted out through the hanging holes 201 by the hooks, then the other catalyst modules 2 can be moved to the opening 100 position in turn for lifting out, and after the new catalyst module 2 is completely loaded, the detachable frame 11 is recovered.
The above embodiments are only for illustrating the technical concept and features of the present invention, and the purpose of the embodiments is to enable people skilled in the art to understand the contents of the present invention and to implement the present invention, which cannot limit the protection scope of the present invention. All equivalent changes and modifications made according to the spirit of the present invention should be covered by the protection scope of the present invention.