SCR denitration pretreatment device and SCR denitration system

Abstract

The invention discloses an improved SCR (Selective Catalytic Reduction) denitration pretreatment device and an SCR denitration system, aiming at solving the technical problems that a pretreatment catalyst adopted at present is high in cost and is damaged. The system comprises a pretreatment reactor, a pretreatment catalyst in the pretreatment reactor forms a first pretreatment catalyst bed layer and a second pretreatment catalyst bed layer, the first pretreatment catalyst bed layer and the second pretreatment catalyst bed layer are sequentially arranged in the flue gas flowing direction, the first pretreatment catalyst bed layer is formed by stacking activated carbon particles, and the second pretreatment catalyst bed layer is formed by stacking activated carbon particles. The second pretreatment catalyst bed layer is formed by stacking porous ceramics. The adsorption performance of the activated carbon particles and the high-temperature-resistant and corrosion-resistant characteristics of the porous ceramic can be effectively utilized, the activated carbon particles and the porous ceramic have a synergistic effect to further remove sulfur dioxide in the flue gas, and dust in the to-be-denitrified flue gas is adsorbed and removed through the pretreatment catalyst. The interception capability on SO2 and dust is improved, and the problems of high use cost, easiness in damage and the like caused by independent use of an activated carbon-based desulfurization catalyst are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of industrial furnace flue gas purification, and in particular to an SCR denitration pretreatment device, an SCR denitration device and an SCR denitration system. Background Art

[0002] The applicant provides an SCR denitration system in a Chinese patent document with publication number CN118491291A, comprising: an SCR denitration pretreatment device, wherein the SCR denitration pretreatment device comprises a pretreatment reactor, the pretreatment reactor has an air inlet for flue gas to be pretreated, an exhaust port for pretreated flue gas, a discharge port for a pretreatment catalyst regeneration liquid, and a pretreatment catalyst loading space located in the pretreatment reactor, and a pretreatment catalyst regeneration liquid spraying device for washing and regenerating the pretreatment catalyst in the pretreatment catalyst loading space (according to the records of the patent document, the pretreatment catalyst adopts a carbon-based pretreatment catalyst). During pretreatment, flue gas mixed with or not mixed with a denitration reducing agent enters the pretreatment reactor from the air inlet of the flue gas to be pretreated, and then is discharged from the exhaust port of the pretreated flue gas after being denitrated by the pretreatment catalyst, so as to clean the pretreatment catalyst in the pretreatment catalyst loading space. When the pretreatment catalyst is washed and regenerated, the regeneration liquid of the pretreatment catalyst is discharged from the regeneration liquid discharge port of the pretreatment catalyst, and the pretreatment catalyst adopts a carbon-based pretreatment catalyst; an SCR denitrification device, wherein the SCR denitrification device comprises an SCR denitrification reactor, and the SCR denitrification reactor has an air inlet for flue gas to be denitrified, an exhaust port for flue gas that has been denitrified, and a denitrification catalyst filling space located in the SCR denitrification reactor. During denitrification, the flue gas mixed with the denitrification reducing agent enters the SCR denitrification reactor from the air inlet for flue gas to be denitrified, and then passes through the denitrification catalyst in the denitrification catalyst filling space (according to the records of the patent document, the denitrification catalyst adopts an activated carbon-based denitrification catalyst) and is then discharged from the exhaust port for the denitrified flue gas; wherein, the exhaust port for the pretreated flue gas of the pretreatment reactor of the SCR denitrification pretreatment device is connected to the air inlet for the flue gas to be denitrified of the SCR denitrification reactor of the SCR denitrification device.

[0003] In the above-mentioned SCR denitration system, the pretreatment reactor of the SCR denitration pretreatment device can further remove sulfur dioxide from the flue gas to be denitrated by utilizing the principle of catalytic flue gas desulfurization (i.e., sulfur dioxide, water, and oxygen in the flue gas are adsorbed on the pretreatment catalyst and react to generate sulfuric acid under the catalytic action of the active components), and remove dust from the flue gas to be denitrated by the pretreatment catalyst, thereby improving the subsequent SCR denitration efficiency. In other words, the flue gas to be denitrated entering the pretreatment reactor must contain a certain amount of water vapor (at least ≥5 vol.%). The inventors have found that the flue gas discharged from the pretreatment reactor still contains water vapor, which will affect the denitration catalyst after entering the SCR denitration reactor with the flue gas to be denitrated, thereby reducing the denitration efficiency. Further research found that: due to their strong polar characteristics, water molecules will compete with reaction gases such as NH3 for adsorption on the surface of activated carbon-based denitrification catalysts, occupying the active sites originally used for catalytic reactions; at the same time, the continued presence of water vapor will cause the activated carbon particles to agglomerate and reduce their specific surface area, making their pore structure loose and reducing the number of effective active sites; more importantly, water molecules may also react with the active ingredients on the surface of activated carbon-based denitrification catalysts or promote the diffusion of certain toxic substances (such as alkali metals) into the activated carbon, resulting in the loss or conversion of active ingredients. These combined effects ultimately reduce the catalytic conversion efficiency of activated carbon-based denitrification catalysts for nitrogen oxides.

[0004] In addition, the pretreatment catalyst currently used by the applicant is the "activated carbon-based desulfurization catalyst" developed by the applicant for catalytic flue gas desulfurization (see paragraph 0113 of the patent document specification with the above-mentioned publication number CN118491291A). However, actual use has found that the activated carbon-based desulfurization catalyst is developed for the catalytic flue gas desulfurization scenario. When used in the SCR denitrification reactor, it is not only costly to use, but also because the temperature during SCR denitrification is often higher than that during catalytic flue gas desulfurization, it also makes the activated carbon-based desulfurization catalyst more easily damaged. Summary of the invention

[0005] The purpose of the present invention is to provide an improved SCR denitration device and an SCR denitration system to solve the technical problem that water vapor in the flue gas to be denitrated affects the denitration catalyst and thus reduces the denitration efficiency. Another purpose of the present invention is to provide an improved SCR denitration pretreatment device and an SCR denitration system to solve the technical problem that the pretreatment catalyst currently used is high in cost and has been damaged.

[0006] In the first aspect, an SCR denitrification device is provided, comprising an SCR denitrification reactor, wherein the SCR denitrification reactor has an air inlet for flue gas to be denitrified, an exhaust port for flue gas that has been denitrified, and a denitrification catalyst loading space located in the SCR denitrification reactor, wherein during denitrification, flue gas mixed with a denitrification reducing agent enters the SCR denitrification reactor from the air inlet for flue gas to be denitrified, passes through the denitrification catalyst in the denitrification catalyst loading space, and is then discharged from the exhaust port for flue gas that has been denitrified; the denitrification catalyst adopts an activated carbon-based denitrification catalyst, and the operating temperature of the activated carbon-based denitrification catalyst is 120°C-200°C; it also comprises a flue gas dehumidification device, which is connected to the air inlet for flue gas to be denitrified, and is used to reduce the water vapor content in the flue gas entering the air inlet for flue gas to be denitrified.

[0007] In a second aspect, an SCR denitration system is provided, comprising an SCR denitration pretreatment device and an SCR denitration device, wherein the SCR denitration pretreatment device comprises a pretreatment reactor, wherein the pretreatment reactor has an air inlet for flue gas to be pretreated, an exhaust port for pretreated flue gas, a discharge port for a pretreatment catalyst regeneration liquid, and a pretreatment catalyst loading space located in the pretreatment reactor, wherein a pretreatment catalyst regeneration liquid spraying device for washing and regenerating the pretreatment catalyst in the pretreatment catalyst loading space is provided on the pretreatment reactor, and during pretreatment, flue gas mixed with or not mixed with a denitration reducing agent enters the pretreatment reactor from the air inlet for flue gas to be pretreated. The pretreatment reactor then passes through the pretreatment catalyst and is then discharged from the pretreated flue gas exhaust port. The sulfur dioxide in the flue gas reacts on the pretreatment catalyst to form sulfuric acid and / or sulfate when passing through the pretreatment catalyst. When the pretreatment catalyst is washed and regenerated, the pretreatment catalyst regeneration liquid acts on the pretreatment catalyst through the pretreatment catalyst regeneration liquid spraying device and is then discharged from the pretreatment catalyst regeneration liquid discharge port. The SCR denitrification device adopts the SCR denitrification device of the first aspect mentioned above, and the pretreated flue gas exhaust port is connected to the flue gas inlet to be denitrified through the flue gas dehumidification device.

[0008] By setting up a flue gas dehumidification device to reduce the water vapor content in the flue gas entering the SCR denitration reactor, the influence of water vapor on the activated carbon-based denitration catalyst can be avoided, and the contact between nitrogen oxides and the denitration catalyst can be ensured to be sufficient, thereby maintaining a high denitration efficiency. At the same time, since the flue gas dehumidification device is arranged between the exhaust port of the pretreated flue gas of the pretreatment reactor and the air inlet of the flue gas to be denitrated of the SCR denitration reactor, it will not affect the water vapor content required by the catalytic flue gas desulfurization principle in the pretreatment reactor (sulfur dioxide, water, and oxygen in the flue gas are adsorbed on the pretreatment catalyst and react to generate sulfuric acid under the catalytic action of the active components), thereby ensuring the pretreatment effect.

[0009] In a third aspect, an SCR denitration pretreatment device is provided, comprising a pretreatment reactor, wherein the pretreatment reactor has an air inlet for flue gas to be pretreated, an exhaust port for pretreated flue gas, a discharge port for a pretreatment catalyst regeneration liquid, and a pretreatment catalyst loading space located in the pretreatment reactor, wherein a pretreatment catalyst regeneration liquid spraying device for washing and regenerating the pretreatment catalyst in the pretreatment catalyst loading space is provided on the pretreatment reactor, and during pretreatment, flue gas mixed or not mixed with a denitration reducing agent enters the pretreatment reactor from the air inlet for the flue gas to be pretreated, then passes through the pretreatment catalyst, and then exits the pretreated flue gas loading space. The treated flue gas is discharged from the exhaust port, the sulfur dioxide in the flue gas reacts on the pretreatment catalyst to form sulfuric acid and / or sulfate when passing through the pretreatment catalyst, and the pretreatment catalyst regeneration liquid is discharged from the pretreatment catalyst regeneration liquid discharge port when the pretreatment catalyst is washed and regenerated; the pretreatment catalyst forms a first pretreatment catalyst bed and a second pretreatment catalyst bed, the first pretreatment catalyst bed and the second pretreatment catalyst bed are arranged in sequence according to the flue gas flow direction, the first pretreatment catalyst bed is formed by stacking activated carbon particles, and the second pretreatment catalyst bed is formed by stacking porous ceramics.

[0010] In a fourth aspect, an SCR denitration system is provided, comprising: an SCR denitration pretreatment device, comprising a pretreatment reactor, the pretreatment reactor having an air inlet for flue gas to be pretreated, an exhaust port for pretreated flue gas, a discharge port for pretreatment catalyst regeneration liquid, and a pretreatment catalyst loading space located in the pretreatment reactor, the pretreatment reactor being provided with a pretreatment catalyst regeneration liquid spraying device for washing and regenerating the pretreatment catalyst in the pretreatment catalyst loading space, the flue gas mixed or not mixed with a denitration reducing agent during pretreatment enters the pretreatment reactor from the air inlet for flue gas to be pretreated, passes through the pretreatment catalyst, and is then discharged from the exhaust port for pretreated flue gas, the sulfur dioxide in the flue gas reacts on the pretreatment catalyst when passing through the pretreatment catalyst to form sulfuric acid and / or sulfate, the pretreatment catalyst is washed and regenerated During denitration, the flue gas mixed with the denitrifying reducing agent enters the SCR denitrifying reactor from the flue gas inlet to be denitrified, passes through the denitrifying catalyst in the denitrifying catalyst loading space, and is discharged from the denitrified flue gas exhaust port; the pretreatment catalyst forms a first pretreatment catalyst bed and a second pretreatment catalyst bed, the first pretreatment catalyst bed and the second pretreatment catalyst bed are arranged in sequence according to the flue gas flow direction, the first pretreatment catalyst bed is formed by stacking activated carbon particles, and the second pretreatment catalyst bed is formed by stacking porous ceramics.

[0011] By forming the first pretreatment catalyst bed and the second pretreatment catalyst bed into the pretreatment catalyst, and arranging them in sequence according to the flue gas flow direction, wherein the first pretreatment catalyst bed is formed by stacking activated carbon particles, and the second pretreatment catalyst bed is formed by stacking porous ceramics, the adsorption performance of activated carbon particles and the high temperature and corrosion resistance of porous ceramics can be effectively utilized, so that the two can work together to further remove sulfur dioxide in the flue gas, and the dust in the flue gas to be denitrified can be adsorbed and removed by the pretreatment catalyst. This combination not only improves the interception capacity of SO2 and dust, but also avoids the problems of high cost and easy damage caused by using activated carbon-based desulfurization catalyst alone.

[0012] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments. Additional aspects and advantages provided by the present invention will be partially given in the following description, partially become apparent from the following description, or be learned through practice. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The drawings constituting a part of this specification are used to assist the understanding of the present invention. The contents provided in the drawings and the related descriptions in this specification can be used to explain the present invention, but do not constitute improper limitations on the present invention.

[0014] Figure 1 This is a schematic diagram of the principle of an SCR denitration system according to Embodiment 1 of the present invention.

[0015] Figure 2 for Figure 1 The schematic diagram of the structure of the SCR denitrification pretreatment device in the SCR denitrification system is shown.

[0016] Figure 3 for Figure 1 A schematic structural diagram of the SCR denitrification device in the SCR denitrification system shown.

[0017] Figure 4 for Figure 2 The schematic diagram of the structure of the partition support frame in the SCR denitration pretreatment device is shown.

[0018] Figure 5 for Figure 2 The schematic diagram of the structure of the catalyst support frame in the SCR denitration pretreatment device is shown.

[0019] Figure 6 It is a schematic structural diagram of an SCR denitration tower (SCR denitration system) according to the second embodiment of the present invention.

[0020] Figure 7 for Figure 1 The schematic diagram of the structure of two adjacent layers of partition support frames and sealing partitions in the SCR denitration pretreatment device in the SCR denitration system is shown.

[0021] Figure 8 for Figure 7 A partial enlarged view of the structure shown at another angle.

[0022] Fig. 9 for Figure 2 A partial enlarged view of the bottom of a Sinosteel tower container.

[0023] Fig.10 This is a schematic diagram of the principle of an SCR denitration system according to Embodiment 3 of the present invention.

[0024] Fig.11 This is a graph showing the relationship between the denitrification efficiency and time in Experimental Example 1.

[0025] Fig.12 This is a graph showing the relationship between the denitrification efficiency and time in Experimental Example 2.

[0026] Fig.13 This is a graph showing the relationship between the denitrification efficiency and time in Experimental Example 3.

[0027] Fig.14 This is a graph showing the relationship between the denitrification efficiency and time in Experimental Example 4.

[0028] Fig.15 This is a graph showing the relationship between the denitrification efficiency and time in Experimental Example 5.

[0029] Fig.16 This is a graph showing the relationship between the denitrification efficiency and time in Experimental Example 6.

[0030] Fig.17 This is a graph showing the relationship between the denitrification efficiency and time in Experimental Example 7.

[0031] Fig.18 This is a graph showing the relationship between the denitrification efficiency and time in Experimental Example 8.

[0032] Fig.19 This is a graph showing the relationship between the denitrification efficiency and time in Experimental Example 9.

[0033] Fig. 20 This is a graph showing the relationship between the denitrification efficiency and time in Experimental Example 10. DETAILED DESCRIPTION

[0034] The present invention is described clearly and completely below in conjunction with the accompanying drawings. A person skilled in the art will be able to implement the present invention based on these descriptions. Before describing the present invention in conjunction with the accompanying drawings, it should be particularly noted that:

[0035] The technical solutions and technical features provided in each section, including the following description, can be combined with each other without conflict. In addition, where possible, these technical solutions, technical features and related combinations can be assigned specific technical themes and protected by relevant patents.

[0036] The embodiments of the present invention involved in the following description are generally only a part of the embodiments rather than all the embodiments. Based on these embodiments, all other embodiments obtained by ordinary technicians in this field without making any creative work should fall within the scope of patent protection.

[0037] The terms "include", "comprises", "have" and any variations thereof in this specification and the corresponding claims and related parts are intended to cover non-exclusive inclusions. Other related terms and units can be reasonably interpreted based on the relevant content provided in this specification.

[0038] Figure 1 This is a schematic diagram of the principle of an SCR denitration system according to Embodiment 1 of the present invention. Figure 2 for Figure 1 The schematic diagram of the structure of the SCR denitrification pretreatment device in the SCR denitrification system is shown. Figure 3 for Figure 1 A schematic structural diagram of the SCR denitrification device in the SCR denitrification system shown. Figure 4 for Figure 2 The schematic diagram of the structure of the partition support frame in the SCR denitration pretreatment device is shown. Figure 5 for Figure 2 The schematic diagram of the structure of the catalyst support frame in the SCR denitration pretreatment device is shown. Fig. 9 for Figure 2 A partial enlarged view of the bottom of a Sinosteel tower container.

[0039] like Figure 1 As shown, the SCR denitration system includes an SCR denitration pretreatment device 1 and an SCR denitration device 2. The SCR denitration pretreatment device 1 is loaded with a pretreatment catalyst 11. The SCR denitration device 2 is loaded with a denitration catalyst 21.

[0040] The SCR denitration pretreatment device 1 comprises a pretreatment reactor, wherein the pretreatment reactor has an air inlet for flue gas to be pretreated, an exhaust port for pretreated flue gas, a discharge port for a pretreatment catalyst regeneration liquid, and a pretreatment catalyst loading space located in the pretreatment reactor. The pretreatment reactor is provided with a pretreatment catalyst regeneration liquid spraying device for washing and regenerating the pretreatment catalyst in the pretreatment catalyst loading space. During pretreatment, flue gas mixed with or not mixed with a denitration reducing agent (NH3) enters the pretreatment reactor from the air inlet for flue gas to be pretreated, passes through the pretreatment catalyst 11, and is then discharged from the exhaust port for pretreated flue gas. When passing through the pretreatment catalyst 11, sulfur dioxide in the flue gas reacts on the pretreatment catalyst 11 to form sulfuric acid and / or sulfate (ammonium sulfate). When washing and regenerating the pretreatment catalyst, the pretreatment catalyst regeneration liquid (dilute sulfuric acid and / or water) is discharged from the discharge port for the pretreatment catalyst regeneration liquid.

[0041] The SCR denitrification device 2 includes an SCR denitrification reactor, which has an air inlet for flue gas to be denitrified, an exhaust port for flue gas that has been denitrified, and a denitrification catalyst loading space located in the SCR denitrification reactor. During denitrification, the flue gas mixed with the denitrification reducing agent (NH3) enters the SCR denitrification reactor from the air inlet for flue gas to be denitrified, passes through the denitrification catalyst 21 in the denitrification catalyst loading space, and is then discharged from the exhaust port for the denitrified flue gas.

[0042] Among them, the working temperature of the pretreatment catalyst 11 is 120℃-200℃, and a first pretreatment catalyst bed and a second pretreatment catalyst bed are formed. The first pretreatment catalyst bed and the second pretreatment catalyst bed are arranged in sequence according to the flue gas flow direction (the second pretreatment catalyst bed is directly stacked on the first pretreatment catalyst bed. Of course, the first pretreatment catalyst bed and the second pretreatment catalyst bed can also be separated by a certain distance). The first pretreatment catalyst bed is formed by stacking activated carbon particles, and the second pretreatment catalyst bed is formed by stacking porous ceramics.

[0043] The porous ceramic can be at least one of alumina porous ceramic, zirconia porous ceramic, silicon nitride porous ceramic, mullite porous ceramic, and titanium oxide porous ceramic, and alumina porous ceramic is specifically used here. The porous ceramic can be ceramic particles or honeycomb ceramics, and ceramic particles are specifically used here.

[0044] The denitration catalyst 21 specifically adopts an activated carbon-based denitration catalyst, and the working temperature of the activated carbon-based denitration catalyst is 120°C-200°C.

[0045] By forming the pretreatment catalyst 11 into a first pretreatment catalyst bed and a second pretreatment catalyst bed, and arranging them in sequence according to the flue gas flow direction, wherein the first pretreatment catalyst bed is formed by stacking activated carbon particles, and the second pretreatment catalyst bed is formed by stacking porous ceramics, the adsorption performance of activated carbon particles and the high temperature and corrosion resistance of porous ceramics can be effectively utilized, so that the two can work together to further remove sulfur dioxide in the flue gas, and the dust in the flue gas to be denitrified can be adsorbed and removed by the pretreatment catalyst. This combination not only improves the interception capacity of SO2 and dust, but also avoids the problems of high cost and easy damage caused by using activated carbon-based desulfurization catalyst alone.

[0046] Alumina porous ceramics have the characteristics of a porous network structure and a large specific surface area. The abundant hydroxyl groups (-OH) on its surface can interact with water molecules through hydrogen bonding, and have a certain dehumidification effect, thereby reducing the water vapor content in the flue gas entering the SCR denitrification device 2, and can reduce the influence of water vapor on the activated carbon-based denitrification catalyst.

[0047] In addition, for details on the amount of activated carbon particles and porous ceramics used in the pretreatment catalyst 11, please refer to the subsequent experimental examples in this specification.

[0048] like Figure 2As shown, the SCR denitration pretreatment device 1 adopts a steel tower container, which includes a steel outer cylinder 31 and a steel inner support system 32 arranged in the steel outer cylinder 31, and the bottom of the steel outer cylinder 31 and the bottom of the steel inner support system 32 are respectively installed on a concrete base 33.

[0049] Among them, the steel internal support system 32 has a central column 321 and multiple layers of horizontal frames 322 arranged at intervals along the axial direction of the central column 321, the radial inner edge of each horizontal frame 322 is welded to the outer surface of the central column 321, and the radial outer edge of each horizontal frame 322 is welded to the inner side surface of the steel outer cylinder 31, so that the central column 321, each horizontal frame 322 and the steel outer cylinder 31 are connected to form a steel tower.

[0050] A portion of the horizontal frames 322 is used as a partition support frame and is paved with a sealing partition 323, and another portion of the horizontal frames 322 is used as a catalyst support frame and is paved with a catalyst breathable support layer, and the catalyst breathable support layer is used to load the pretreatment catalyst 11.

[0051] In addition, a reaction chamber is formed between any two adjacent layers of sealing partitions 323, at least one catalyst breathable support layer is provided in any reaction chamber, and a chamber located below the at least one catalyst breathable support layer in any reaction chamber is provided with a lower air vent 324, and a chamber located above the at least one catalyst breathable support layer is provided with an upper air vent 325, and one of the lower air vent 324 and the upper air vent 325 of any reaction chamber is an air inlet and the other is an exhaust port.

[0052] In the above steel tower container, the steel outer cylinder 31 and the steel inner support system 32 (including the central column 321 and the horizontal frame 322) are welded together to form an integrated steel tower. The horizontal frame 322 is divided into two types: one is used as a partition support frame (see Figure 5 ) paving sealing partition 323, and another type as catalyst support frame (see Figure 4 ) is paved with a catalyst permeable support layer. A reaction chamber is formed between two adjacent layers of sealed baffles 323, and each reaction chamber is provided with an air inlet and an exhaust port. The design of this steel tower container solves the technical problems of the existing SCR denitration pretreatment device with complex structure, difficult engineering construction cycle control and long construction cycle.

[0053] The innovation of the above-mentioned steel tower container is mainly reflected in the integrated structural design: by welding the steel outer cylinder 31 and the steel inner support system 32 (including the central column and the horizontal frame) into a whole, the problem of the reactor cylinder and the tower frame being built separately in the traditional design is avoided. The steel outer cylinder 31 and the steel inner support system 32 jointly support the steel tower container, saving the amount of materials. Among them, the horizontal frame 322 is divided into two types: the partition support frame and the catalyst support frame, which are respectively paved with the sealing partition and the catalyst breathable support layer, and the reaction chamber is formed by the adjacent sealing partitions. The catalyst breathable support layer and the upper and lower vents are arranged in each reaction chamber. This overall welding design simplifies the structure. The steel inner support system 32 not only plays a supporting force role, but is also used to directly install the sealing partition and the catalyst breathable support layer, which greatly simplifies the structure of the SCR denitration pretreatment device and shortens the construction period.

[0054] Specifically, if Figure 4-Figure 5 As shown, the horizontal frame 322 is mainly composed of a plurality of radial steel beams 322a and annular steel beams 322b connected between the radial steel beams 322a, one end of each of the radial steel beams is welded to the outer side of the central column 321 and the other end is welded to the inner side of the outer cylinder 31. The radial steel beams 322a and the annular steel beams 322b can be made of steel materials such as T-shaped steel and H-shaped steel.

[0055] Fig. 9 for Figure 2 A partial enlarged view of the bottom of a Sinosteel tower vessel. Specifically, Fig. 9 As shown, an annular seat plate 34 is provided at the bottom edge of the steel outer cylinder 31, and the bottom of the side wall of the steel outer cylinder 31 is welded to the annular seat plate 34. A plurality of ribs 35 are circumferentially arranged at intervals on the annular seat plate 34, and the bottom edges of these ribs 35 are welded to the annular seat plate 34 and the inner sides are welded to the outer surface of the steel outer cylinder 31. The annular seat plate 34 is fixed to the concrete base 33 by anchor bolts 36, and the annular seat plate 34 is connected to the central column 321 by a bottom plate 37.

[0056] The bottom structure design of the above-mentioned steel tower container has multiple advantages: the annular seat plate 34 provides a uniform and stable force-bearing surface for the entire tower, and the overall rigidity is enhanced by cooperating with a plurality of rib plates 35 arranged at intervals in the circumferential direction. At the same time, the rib plates 35 strengthen the connection between the outer cylinder 31 and the annular seat plate 34 by welding, thereby improving the anti-overturning ability of the structure; the bottom plate 37 effectively connects the central column 321 and the annular seat plate 34 into a whole, forming a stable support system; a reliable connection with the concrete base 33 is achieved through anchor bolts 36, which is convenient for on-site installation and adjustment; the entire structural design is simple and clear, and the connection method is standardized, which not only ensures the construction quality, but also facilitates subsequent inspection and maintenance. At the same time, due to the use of a reasonable connection method, better cost-effectiveness is achieved.

[0057] like Figure 3 As shown, the SCR denitrification device 2 also adopts a steel tower container, which also includes a steel outer cylinder 31 and a steel inner support system 32 arranged in the steel outer cylinder 31, and the bottom of the steel outer cylinder 31 and the bottom of the steel inner support system 32 are respectively installed on a concrete base 33.

[0058] The steel inner support system 32 of the SCR denitrification device 2 has a central column 321 and multiple layers of horizontal frames 322 spaced apart along the axial direction of the central column 321. The radial inner edge of each horizontal frame 322 is welded to the outer surface of the central column 321, and the radial outer edge of each horizontal frame 322 is welded to the inner surface of the steel outer cylinder 31, so that the central column 321, each horizontal frame 322 and the steel outer cylinder 31 are connected to form a steel tower.

[0059] Among the above-mentioned horizontal frames 322, a part of the horizontal frames 322 is used as a partition support frame and is paved with a sealing partition 323, and another part of the horizontal frames 322 is used as a catalyst support frame and is paved with a catalyst breathable support layer, and the catalyst breathable support layer is used to load the denitration catalyst 21.

[0060] In addition, a reaction chamber is formed between any two adjacent layers of sealing partitions 323, at least one catalyst breathable support layer is provided in any reaction chamber, and a chamber located below the at least one catalyst breathable support layer in any reaction chamber is provided with a lower air vent 324, and a chamber located above the at least one catalyst breathable support layer is provided with an upper air vent 325, and one of the lower air vent 324 and the upper air vent 325 of any reaction chamber is an air inlet and the other is an exhaust port.

[0061] The central column 321 is made of a central ventilation pipe, the upper end of which extends upward from the steel outer cylinder, and openings serving as lower ventilation ports 324 of corresponding reaction chambers are arranged at intervals on the side walls of the central ventilation pipe.

[0062] In addition, similarly, an annular seat plate 34 is provided at the bottom edge of the steel outer cylinder 31 of the SCR denitrification device 2, and the bottom of the side wall of the steel outer cylinder 31 is welded to the annular seat plate 34. A plurality of ribs 35 are circumferentially spaced on the annular seat plate 34, and the bottom edges of these ribs 35 are welded to the annular seat plate 34 and the inner edges are welded to the outer surface of the steel outer cylinder 31. The annular seat plate 34 is fixed to the concrete base 33 by anchor bolts 36, and the annular seat plate 34 is connected to the central column 321 by a bottom plate 37.

[0063] In the above-mentioned SCR denitration system, the exhaust port of any reaction chamber in the SCR denitration pretreatment device 1 is connected to the air inlet of the corresponding reaction chamber in the SCR denitration device 2 .

[0064] Specifically, each reaction chamber in the SCR denitration pretreatment device 1 corresponds to each reaction chamber in the SCR denitration device 2, so that the exhaust port of any reaction chamber in the SCR denitration pretreatment device 1 is connected to the air inlet of a corresponding reaction chamber in the SCR denitration device 2 through an independent flue. In addition, the two ends of the flue are connected to the corresponding exhaust port and air inlet through an expansion joint 4 (see Figure 1 ).

[0065] The above-mentioned SCR denitration system corresponds each reaction chamber of the SCR denitration pretreatment device 1 and the SCR denitration device 2 one by one and connects them through independent flues, ensuring that the airflows between the reaction chambers are independent of each other and avoiding airflow mixing, so that the reaction conditions in each reaction chamber can be accurately controlled; at the same time, the design of using expansion joints 4 to connect both ends of the independent flues can effectively compensate for the deformation caused by thermal expansion and contraction, ensuring the stability and sealing of the system operation; in addition, this modular one-to-one correspondence design also facilitates the maintenance and overhaul of the system. When a reaction chamber needs maintenance, only the corresponding flue can be closed without affecting the normal operation of other reaction chambers, thereby improving the maintainability and operation efficiency of the SCR denitration system.

[0066] In the SCR denitration pretreatment device 1 of the above-mentioned SCR denitration system, the lower air vent 324 and the upper air vent 325 of each reaction chamber are both arranged on the side wall of the steel outer cylinder 31; in the SCR denitration device 2 of the above-mentioned SCR denitration system, the upper air vent 325 of each reaction chamber is both arranged on the side wall of the steel outer cylinder 31, and the lower air vent 324 of each reaction chamber is distributed on the central column 321 (central air pipe).

[0067] When the SCR denitration system is in operation, the flue gas to be denitrated first enters each reaction chamber of the SCR denitration pretreatment device 1, enters the corresponding reaction chamber through the lower vent 324 arranged on the side wall of the steel outer cylinder 31 of the SCR denitration pretreatment device 1, flows upward through the catalyst permeable support layer equipped with the pretreatment catalyst 11, and then is discharged from the upper vent 325 on the side wall of the steel outer cylinder 31. The pretreated flue gas enters each reaction chamber of the SCR denitration device 2 through the independent flue and expansion joint 4, enters the corresponding reaction chamber through the upper vent 325 arranged on the side wall of the steel outer cylinder 31 of the SCR denitration device 2, flows downward through the catalyst permeable support layer equipped with the denitration catalyst 21, and finally enters the central vent pipe from the lower vent 324 on the central column 321 (central vent pipe) and flows out of the SCR denitration device 2 from bottom to top. This design allows each independent flue between the SCR denitration pretreatment device 1 and the SCR denitration device 2 to be arranged horizontally (see Figure 1 As shown), the smoke flow distance is shortened and the smoke flow resistance is reduced.

[0068] In other embodiments, the central column 321 in the SCR denitration pretreatment device 1 may also adopt a central ventilation pipe, and the flue gas to be denitrated may be distributed to each reaction chamber of the SCR denitration pretreatment device 1 through the central ventilation pipe.

[0069] Figure 7 for Figure 1 The schematic diagram of the structure of two adjacent layers of partition support frames and sealing partitions in the SCR denitration pretreatment device in the SCR denitration system is shown. Figure 8 for Figure 7 A partial enlarged view of the structure shown at another angle. Figure 8 The sealing partition 323 in the embodiment is made transparent so as to observe the horizontal frame 322 at the bottom of the sealing partition 323. Figure 7-Figure 8The invention mainly illustrates how to install a pre-treatment catalyst regeneration liquid spraying device and a method of conveying the pre-treatment catalyst regeneration liquid in an SCR denitration pre-treatment device. The applicant has introduced the working principle of the pre-treatment catalyst regeneration liquid spraying device in the Chinese patent document with the publication number CN118491291A. In the present application, the pre-treatment catalyst regeneration liquid spraying device can be installed on the horizontal frame 322 at the lower part of each sealing partition 323. In order to supply the pre-treatment catalyst regeneration liquid to the pre-treatment catalyst regeneration liquid spraying device and recover the pre-treatment catalyst regeneration liquid after spraying, a pre-treatment catalyst regeneration liquid input pipeline and a pre-treatment catalyst regeneration liquid recovery pipeline are provided in the central column 321. The pre-treatment catalyst regeneration liquid input pipeline is connected to the pre-treatment catalyst regeneration liquid spraying device through the first opening 321a on the central column 321 (disposed below the adjacent sealing partition 323), and the pre-treatment catalyst regeneration liquid recovery pipeline is connected to the second opening 321b on the central column 321 (disposed above the adjacent sealing partition 323). Thus, the pretreatment catalyst regeneration liquid will be transported through the pretreatment catalyst regeneration liquid input pipeline arranged inside the central column 321, and enter the pretreatment catalyst regeneration liquid spraying device installed under the horizontal frame 322 through the first opening 321a on the central column 321. The spraying device sprays the regeneration liquid onto the surface of the pretreatment catalyst 11 for regeneration. The used regeneration liquid flows to the sealing partition 323 below under the action of gravity, and enters the pretreatment catalyst regeneration liquid recovery pipeline through the second opening 321b on the central column 321 located above the sealing partition 323, thereby realizing the recycling of the pretreatment catalyst regeneration liquid.

[0070] The SCR denitration pretreatment device 1 and the SCR denitration device 2 of the above-mentioned SCR denitration system are independently arranged. Based on the structure of the above-mentioned steel tower container, the SCR denitration system will be further improved so that the SCR denitration pretreatment device 1 and the SCR denitration device 2 are combined into one.

[0071] Figure 6 FIG. 1 is a schematic diagram of the structure of an SCR denitration tower (SCR denitration system) according to the second embodiment of the present invention. Figure 6 As shown, the SCR denitration tower comprises a plurality of reaction units arranged vertically, wherein a lower packing layer and an upper packing layer are respectively provided in any reaction unit, wherein the lower packing layer is composed of a pretreatment catalyst 11, and the upper packing layer is composed of a denitration catalyst 21; and an air inlet is provided in a chamber below the lower packing layer in any reaction unit, and an exhaust port is provided in a chamber above the upper packing layer in any reaction unit. Optionally, a reaction unit is formed between any two adjacent layers of sealing baffles. In addition, the operating temperature of the pretreatment catalyst and the denitration catalyst is 120°C-200°C.

[0072] Specifically, the SCR denitration tower is a steel tower container, which includes a steel outer cylinder and a steel inner support system arranged in the steel outer cylinder, the bottom of the steel outer cylinder and the bottom of the steel inner support system are respectively installed on a concrete base; the steel inner support system has a central column and multiple layers of horizontal frames arranged at intervals along the axial direction of the central column, the radial inner edge of each horizontal frame is welded to the outer side of the central column, and the radial outer edge of each horizontal frame is welded to the inner side of the steel outer cylinder, so that the central column and each horizontal frame are welded to the inner side of the steel outer cylinder. and the steel outer cylinder are connected to form a steel tower; a part of the horizontal frames are used as partition support frames and are paved with sealed partitions, and another part of the horizontal frames are used as catalyst support frames and are paved with catalyst breathable support layers; a reaction unit is formed between at least some of the different sealed partitions, and at least two layers of catalyst breathable support layers are arranged in any reaction unit, and the lower catalyst breathable support layer of the at least two catalyst breathable support layers is used to load the pretreatment catalyst, and the upper catalyst breathable support layer of the at least two catalyst breathable support layers is used to load the denitration catalyst.

[0073] The pretreatment catalyst 11 also forms a first pretreatment catalyst bed layer and a second pretreatment catalyst bed layer, wherein the first pretreatment catalyst bed layer is formed by stacking activated carbon particles, and the second pretreatment catalyst bed layer is formed by stacking porous ceramics, which are specifically alumina porous ceramics (ceramic particles).

[0074] The denitration catalyst 21 is an activated carbon-based denitration catalyst, and the operating temperature of the activated carbon-based denitration catalyst is 120°C-200°C.

[0075] Optionally, the horizontal frame is mainly composed of a plurality of radial steel beams and annular steel beams connected between the radial steel beams, one end of the radial steel beams is welded to the outer surface of the central column and the other end is welded to the inner surface of the outer cylinder.

[0076] Optionally, an annular seat plate is provided on the bottom edge of the steel outer cylinder, the bottom of the side wall of the steel outer cylinder is welded to the annular seat plate, a plurality of rib plates are circumferentially spaced apart on the annular seat plate, the bottom edges of these rib plates are welded to the annular seat plate and the inner edges are welded to the outer surface of the steel outer cylinder, the annular seat plate is fixed to the concrete base by anchor bolts, and the annular seat plate is connected to the center column by a base plate.

[0077] Optionally, the central column is made of a central ventilation pipe, the upper end of which extends upward from the steel outer cylinder, and the side walls of the central ventilation pipe are provided with openings serving as air inlets or exhaust ports of corresponding reaction chambers at intervals.

[0078] Optionally, different catalyst permeable support layers in at least some of the reaction chambers are isolated from each other by providing a partition support frame and a corresponding sealing partition, and the chambers isolated by the sealing partition in the same reaction unit are connected by a pressurized air distribution channel. The pressurized air distribution channel is arranged on the outside of the steel outer cylinder and adopts an arc-shaped pipeline.

[0079] The above-mentioned SCR denitrification tower innovatively integrates the pretreatment catalyst 11 and the denitrification catalyst 21 in different packing layers within the same SCR denitrification tower, and realizes a compact design through multiple vertically arranged reaction units. The lower packing layer (pretreatment catalyst) and the upper packing layer (denitrification catalyst) in each reaction unit can operate collaboratively at similar working temperatures, and the structural design of the steel tower container (including central column, horizontal frame, sealing partition, etc.) is set up to reduce the equipment footprint and construction cost.

[0080] The pressurized air distribution channel is in the form of an arc-shaped pipe arranged on the outside of the steel outer cylinder, which is used to connect the chambers isolated by the sealed partition in the same reaction unit. When the flue gas enters from the air inlet at the bottom of the reaction unit, part of the gas will be compressed through the pressurized air distribution channel, which can promote a more uniform flow distribution of the gas in the reaction unit. The gas is first pretreated by the pretreatment catalyst in the lower packing layer, and then denitrified by the denitrification catalyst in the upper packing layer, and finally discharged from the exhaust port of the upper chamber. This design optimizes the airflow distribution by pressurizing the air distribution, ensuring that the catalyst layer can get uniform gas contact, thereby improving the processing efficiency of the entire reaction unit.

[0081] In addition, the above-mentioned SCR denitration tower can also be installed with a pre-treatment catalyst regeneration liquid spraying device in the aforementioned manner to realize the circulation of the pre-treatment catalyst regeneration liquid.

[0082] Fig.10 The schematic diagram of the principle of an SCR denitration system of the third embodiment of the present invention is shown in FIG. The SCR denitration system of the third embodiment is improved on the basis of the SCR denitration system of the first embodiment, so that the SCR denitration device 2 includes a flue gas dehumidification device 5, and the exhaust port of the pre-treated flue gas is connected to the inlet of the flue gas to be denitrated through the flue gas dehumidification device 5.

[0083] By setting up the flue gas dehumidification device 5 to reduce the water vapor content in the flue gas entering the SCR denitration reactor, the influence of water vapor on the activated carbon-based denitration catalyst can be avoided, and the contact degree between nitrogen oxides and the denitration catalyst is guaranteed, thereby maintaining a high denitration efficiency. At the same time, since the flue gas dehumidification device 5 is arranged between the exhaust port of the pretreated flue gas of the pretreatment reactor and the air inlet of the flue gas to be denitrated of the SCR denitration reactor, it will not affect the water vapor content required by the catalytic flue gas desulfurization principle in the pretreatment reactor (sulfur dioxide, water, and oxygen in the flue gas are adsorbed on the pretreatment catalyst and react to generate sulfuric acid under the catalytic action of the active components), thereby ensuring the pretreatment effect.

[0084] Specifically, the flue gas dehumidification device 5 adopts a condenser, and the condenser is connected to the air inlet of the flue gas to be denitrified through a heater 6.

[0085] The heater 6 uses water vapor as a heat source (ie, the heater 6 is a steam heater), and the water vapor comes from a public steam source of the factory where the SCR denitration device is located.

[0086] In addition, the SCR denitration reactor is provided with a denitration catalyst regeneration liquid spraying device for washing and regenerating the denitration catalyst 21 in the denitration catalyst filling space. The SCR denitration reactor also has a denitration catalyst regeneration liquid discharge port. When the denitration catalyst is washed and regenerated, the denitration catalyst regeneration liquid acts on the denitration catalyst through the denitration catalyst regeneration liquid spraying device and is discharged from the denitration catalyst regeneration liquid discharge port.

[0087] At the same time, the SCR denitrification device 2 further includes a drying device, which includes a blower 7 and a drying gas distribution network. The blower 7 and the heater 6 can be connected to the SCR denitrification reactor through the drying gas distribution network, so that the airflow generated by the blower 7 is heated by the heater 6 to form drying gas and enters the SCR denitrification reactor after the denitrification catalyst is washed and regenerated and passes through the denitrification catalyst 21 of the SCR denitrification reactor. When the drying gas passes through the denitrification catalyst, the denitrification catalyst regeneration liquid attached to the denitrification catalyst evaporates and is discharged from the SCR denitrification reactor, so that the SCR denitrification reactor can quickly resume working condition.

[0088] Furthermore, the blower 7 and the heater 6 can be connected to the pretreatment reactor through the drying gas distribution pipeline network, so that the airflow generated by the blower 7 is heated by the heater 6 to form drying gas and enters the pretreatment reactor after the pretreatment catalyst is washed and regenerated and passes through the pretreatment catalyst 11 of the pretreatment reactor. When the drying gas passes through the pretreatment catalyst, the pretreatment catalyst regeneration liquid attached to the pretreatment catalyst evaporates and is discharged from the pretreatment reactor, so that the pretreatment reactor can quickly resume working state.

[0089] The drying gas distribution pipeline network can simultaneously or sequentially input the drying gas into the pretreatment reactor and the SCR denitration reactor.

[0090] like Fig.10 As shown, in the third embodiment, when valves K1, K2, K3, and K4 are opened, Fig.10 When the other valves are closed, the flue gas first passes through the pretreatment reactor, and SO2 is removed and preliminarily dehumidified through the activated carbon particle layer and the alumina porous ceramic double-layer catalyst; then the flue gas enters the condenser for deep dehumidification and is heated by the steam heater; when the steam heater is heated to a temperature of 120-200°C, the dehumidified flue gas is mixed with NH3 and enters the SCR denitration reactor to complete NOx removal. After spraying and washing the pretreatment catalyst 11 and the denitration catalyst 21, valves K1, K2, K3, and K4 are closed, and valves K5, K6, K7, and K8 are opened. The drying system (composed of a blower 7, a heater 6, and a drying gas distribution network) serves the drying of the corresponding catalysts in the pretreatment reactor and the SCR denitration reactor at the same time.

[0091] Experimental example

[0092] according to Fig.10 A set of experimental equipment was prepared for the SCR denitrification system shown in the figure, and the following two groups of experiments were carried out respectively.

[0093] The first set of experiments

[0094] The experimental flue gas is a mixture of N2, O2, NO and SO2 by a gas distribution device, in which N2 is the carrier gas, NO concentration is about 700ppm, SO2 concentration is about 300ppm, H2O content is 5%, and O2 concentration is between 5% and 6%. The above concentrations are all volume ratios.

[0095] The temperature of the pretreatment reactor is 150℃, and the temperature of the SCR denitration reactor is 150℃. The flue gas first passes through the pretreatment reactor and then into the SCR denitration reactor, and NH3 is directly passed into the pretreatment reactor. The concentration of the original gas and the flue gas after denitration is detected by Wuhan Sifang online flue gas analyzer.

[0096] The denitration catalyst 21 specifically adopts an activated carbon-based denitration catalyst. The pretreatment catalyst 11 adopts common activated carbon, activated carbon-based desulfurization catalyst, alumina porous ceramic (ceramic particles), and common activated carbon + alumina porous ceramic (ceramic particles).

[0097] Experimental Example 1: Pretreatment catalyst using ordinary activated carbon

[0098] The temperature of the pretreatment reactor is 150°C, the temperature of the SCR denitration reactor is 150°C, and the space velocity in the pretreatment reactor is 5000h -1 , the space velocity in the SCR denitrification reactor is 7500h -1 The particle size of activated carbon-based denitrification catalyst and ordinary activated carbon is 20-80 mesh. Fig.11 It can be seen that in the first cycle, the denitrification efficiency was about 91% after the introduction of SO2 and H2O, and in the second cycle the denitrification efficiency was above 86%, indicating that ordinary activated carbon can intercept SO2 in the flue gas, thereby avoiding poisoning of the denitrification catalyst.

[0099] Experimental Example 2: Pretreatment catalyst using activated carbon-based desulfurization catalyst

[0100] The temperature of the pretreatment reactor is 150°C, the temperature of the SCR denitration reactor is 150°C, and the space velocity in the pretreatment reactor is 5000h -1 , the space velocity in the SCR denitrification reactor is 7500h -1 The particle size of activated carbon-based denitrification catalyst and activated carbon-based desulfurization catalyst is 20-80 mesh. Fig.12 It can be seen that in the first cycle, the denitrification efficiency is above 90%, and in the second cycle, the denitrification efficiency is above 75%. The activated carbon-based desulfurization catalyst has poor desulfurization ability here. Although it can intercept a part of SO2 and thus ensure a certain denitrification efficiency, its price is much more expensive than ordinary activated carbon.

[0101] Experimental Example 3: Pretreatment catalyst using alumina porous ceramic (ceramic particles)

[0102] The temperature of the pretreatment reactor is 150°C, the temperature of the SCR denitration reactor is 150°C, and the space velocity in the pretreatment reactor is 5000h -1 , the space velocity in the SCR denitrification reactor is 7500h -1 The particle size of activated carbon-based denitrification catalyst and alumina porous ceramic is 20-80 mesh. Fig.13 It can be seen that: in the first cycle, the denitrification efficiency is above 95%, which is a good denitrification efficiency, higher than the denitrification efficiency when the pretreatment catalyst is ordinary activated carbon. However, the denitrification efficiency in the second cycle is about 76%.

[0103] Experimental Example 4: Pretreatment catalyst using ordinary activated carbon + alumina porous ceramic (ceramic particles)

[0104] The temperature of the pretreatment reactor is 150°C, the temperature of the SCR denitration reactor is 150°C, and the space velocity in the pretreatment reactor is 5000h -1 , the space velocity in the SCR denitrification reactor is 7500h -1 The particle sizes of the activated carbon-based denitration catalyst and the porous alumina ceramic are both 20-80 mesh. The height ratio of the activated carbon-based denitration catalyst bed to the porous alumina ceramic bed is 1. Fig.14 It can be seen that the denitrification efficiency is still maintained above 80% at the 65th hour. When the pretreatment system is observed after the experiment, white precipitation and agglomeration appear on the ordinary activated carbon and ceramics, and no white substance is produced on the denitrification catalyst, indicating that the ceramics and ordinary activated carbon work together to better intercept SO2 and H2O, and the effect is significantly enhanced compared with when each is used as a filler alone.

[0105] The first set of experimental conclusions: When the activated carbon-based desulfurization catalyst is used as a pretreatment catalyst, although it can intercept a part of SO2 and thus ensure a certain denitrification efficiency, its price is much more expensive than that of ordinary activated carbon. Considering comprehensively, it is not suitable as a pretreatment material. The ceramic and ordinary activated carbon work together to better intercept SO2 and H2O, and the effect is significantly enhanced compared to when each is used as a pretreatment catalyst alone.

[0106] The second set of experiments

[0107] The experimental flue gas is a mixture of N2, O2, NO and SO2 by a gas distribution device, in which N2 is the carrier gas, NO concentration is about 700ppm, SO2 concentration is about 300ppm, H2O content is 5%, and O2 concentration is between 5% and 6%. The above concentrations are all volume ratios.

[0108] The temperature of the pretreatment reactor is 150℃, and the temperature of the SCR denitration reactor is 150℃. The flue gas first passes through the pretreatment reactor and then into the SCR denitration reactor, and NH3 is directly passed into the pretreatment reactor. The concentration of the original gas and the flue gas after denitration is detected by Wuhan Sifang online flue gas analyzer.

[0109] The denitration catalyst 21 specifically uses an activated carbon-based denitration catalyst. The pretreatment catalyst 11 uses ordinary activated carbon + alumina porous ceramic (ceramic particles). The air velocity in the SCR denitration reactor is maintained at 7500h -1 The second set of experiments studied the pretreatment reactor with a space velocity of 10000 h -1 、20000h -1 、30000h -1 and 40000h -1The denitrification efficiency.

[0110] Experimental Example 5: The height ratio of the activated carbon-based denitration catalyst bed to the alumina porous ceramic bed is 1, and the pretreatment reactor space velocity is 10000h -1 .

[0111] like Fig.15 It can be seen that the denitrification efficiency was above 90% before 14 hours, and remained above 88% after 14 hours, and the denitrification efficiency was relatively stable with a small decline.

[0112] Experimental Example 6: The height ratio of the activated carbon-based denitration catalyst bed to the alumina porous ceramic bed is 1, and the pretreatment reactor space velocity is 20,000 h -1 .

[0113] like Fig.16 It can be seen that the denitrification efficiency has been around 86%, and the denitrification efficiency is stable without major fluctuations.

[0114] Experimental Example 7: The height ratio of the activated carbon-based denitration catalyst bed to the alumina porous ceramic bed is 1, and the pretreatment reactor space velocity is 30,000 h -1 .

[0115] like Fig.17 It can be seen that the denitrification efficiency has been around 85%, which is consistent with the 20000h -1 The time difference is very small.

[0116] Experimental Example 8: The height ratio of the activated carbon-based denitration catalyst bed to the alumina porous ceramic bed is 1, and the pretreatment reactor space velocity is 30,000 h -1 .

[0117] like Fig.18 It can be seen that the denitration efficiency is 81%, and the denitration efficiency is stable during the experiment. However, after 24 hours, the pretreatment reactor was blocked and a large amount of white matter was generated on the surface of the denitration catalyst.

[0118] Experimental Example 9: The height ratio of the activated carbon-based denitration catalyst bed to the alumina porous ceramic bed is 4, and the pretreatment reactor space velocity is 20,000 h -1 .

[0119] like Fig.19 It can be seen that the desulfurization efficiency is about 76%. However, a small amount of white solid matter is generated in the denitrification reactor.

[0120] Experimental Example 10: The height ratio of the activated carbon-based denitration catalyst bed to the alumina porous ceramic bed is 1:4, and the pretreatment reactor space velocity is 20,000 h -1 .

[0121] like Fig. 20 It can be seen that the denitration efficiency is about 89%, which is similar to the effect when the height ratio is 1:1. However, a large amount of white solid matter is generated in the denitration reactor.

[0122] The second set of experimental conclusions: The optimal space velocity of the pretreatment reactor is 20000h -1 -35000h -1 ; Taking all factors into consideration, the optimal range of the height ratio of the ordinary activated carbon bed to the alumina porous ceramic bed is 1-2.5.

[0123] The above is a description of the relevant contents of the present invention. A person skilled in the art will be able to implement the present invention based on these descriptions. Based on the above contents of this specification, all other embodiments obtained by a person skilled in the art without making creative work should fall within the scope of the present invention.

Claims

1. An SCR denitration pretreatment device, comprising a pretreatment reactor, wherein the pretreatment reactor has an air inlet for flue gas to be pretreated, an exhaust port for pretreated flue gas, a discharge port for a pretreatment catalyst regeneration liquid, and a pretreatment catalyst loading space located in the pretreatment reactor, wherein the pretreatment reactor is provided with a pretreatment catalyst regeneration liquid spraying device for washing and regenerating the pretreatment catalyst in the pretreatment catalyst loading space, wherein during pretreatment, flue gas mixed with or not mixed with a denitration reducing agent enters the pretreatment reactor from the air inlet for flue gas to be pretreated, passes through the pretreatment catalyst, and is then discharged from the exhaust port for pretreated flue gas, wherein sulfur dioxide in the flue gas reacts on the pretreatment catalyst to form sulfuric acid and / or sulfate when passing through the pretreatment catalyst, and when the pretreatment catalyst is washed and regenerated, the pretreatment catalyst regeneration liquid is discharged from the discharge port for the pretreatment catalyst regeneration liquid; wherein: The pretreatment catalyst forms a first pretreatment catalyst bed and a second pretreatment catalyst bed, the first pretreatment catalyst bed and the second pretreatment catalyst bed are arranged in sequence according to the flue gas flow direction, the first pretreatment catalyst bed is formed by stacking activated carbon particles, and the second pretreatment catalyst bed is formed by stacking porous ceramics.

2. The SCR denitration pretreatment device according to claim 1, characterized in that: The space velocity of the pretreatment reactor is ≤35000h -1 ; The ratio of the height of the first pretreatment catalyst bed to the height of the second pretreatment catalyst bed is 1-2.

5.

3. The SCR denitration pretreatment device according to claim 2, characterized in that: The space velocity of the pretreatment reactor is ≥20000h -1 .

4. The SCR denitration pretreatment device according to claim 1, characterized in that: The porous ceramic is at least one of alumina porous ceramic, zirconia porous ceramic, silicon nitride porous ceramic, mullite porous ceramic and titanium oxide porous ceramic.

5. The SCR denitration pretreatment device according to claim 1, characterized in that: The porous ceramic is ceramic particles or honeycomb ceramics. 6.SCR denitrification system, including: The SCR denitration pretreatment device comprises a pretreatment reactor, wherein the pretreatment reactor has an air inlet for flue gas to be pretreated, an exhaust port for pretreated flue gas, a discharge port for a pretreatment catalyst regeneration liquid, and a pretreatment catalyst loading space located in the pretreatment reactor, wherein the pretreatment reactor is provided with a pretreatment catalyst regeneration liquid spraying device for washing and regenerating the pretreatment catalyst in the pretreatment catalyst loading space, wherein during pretreatment, flue gas mixed with or not mixed with a denitration reducing agent enters the pretreatment reactor from the air inlet for flue gas to be pretreated, passes through the pretreatment catalyst, and is then discharged from the exhaust port for pretreated flue gas, wherein sulfur dioxide in the flue gas reacts on the pretreatment catalyst to form sulfuric acid and / or sulfate when passing through the pretreatment catalyst, and when the pretreatment catalyst is washed and regenerated, the pretreatment catalyst regeneration liquid is discharged from the discharge port for the pretreatment catalyst regeneration liquid; The SCR denitration device comprises an SCR denitration reactor, wherein the SCR denitration reactor has an air inlet for flue gas to be denitrated, an exhaust port for flue gas that has been denitrated, and a denitration catalyst loading space located in the SCR denitration reactor. During denitration, flue gas mixed with a denitration reducing agent enters the SCR denitration reactor from the air inlet for flue gas to be denitrated, passes through the denitration catalyst in the denitration catalyst loading space, and is then discharged from the exhaust port for flue gas that has been denitrated; the device is characterized in that: the pretreatment catalyst forms a first pretreatment catalyst bed and a second pretreatment catalyst bed, the first pretreatment catalyst bed and the second pretreatment catalyst bed are arranged in sequence according to the flue gas flow direction, the first pretreatment catalyst bed is formed by stacking activated carbon particles, and the second pretreatment catalyst bed is formed by stacking porous ceramics.

7. The SCR denitration system according to claim 6, characterized in that: The space velocity of the pretreatment reactor is ≤35000h -1 ; The ratio of the height of the first pretreatment catalyst bed to the height of the second pretreatment catalyst bed is 1-2.

5.

8. The SCR denitration system according to claim 7, characterized in that: The space velocity of the pretreatment reactor is ≥20000h -1 .

9. The SCR denitration system according to claim 6, characterized in that: The porous ceramic is at least one of alumina porous ceramic, zirconia porous ceramic, silicon nitride porous ceramic, mullite porous ceramic, and titanium oxide porous ceramic; and / or the porous ceramic is ceramic particles or honeycomb ceramic.

10. The SCR denitration system according to claim 6, characterized in that: The denitration catalyst is an activated carbon-based denitration catalyst.

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