Ammonia-free denitration system based on SCR (selective catalytic reduction) system transformation

Abstract

The utility model discloses an ammonia-free denitration system modified based on an SCR (Selective Catalytic Reduction) system, which comprises a denitration tower in the original SCR system, a smoke inlet is arranged at the upper part of the denitration tower, a smoke outlet is arranged at the lower part of the denitration tower, a placing space for placing a catalyst is arranged in the denitration tower, and the ammonia-free denitration system further comprises a bearing monomer for containing an ammonia-free denitration agent, each bearing single body comprises a single body enclosure structure and a porous bottom plate, the upper end of each single body enclosure structure is open, the lower end of each single body enclosure structure is connected with the porous bottom plate, the single body enclosure structures and the porous bottom plate define a containing space used for containing the ammonia-free denitration agent, a plurality of flue gas flow guide holes are formed in the porous bottom plate, and the flue gas flow guide holes are arranged in the mode that the ammonia-free denitration agent of the minimum unit cannot penetrate through the flue gas flow guide holes; the plurality of bearing monomers are detachably distributed in the placing space, and the bearing monomers are fully distributed on the transverse section of the denitration tower, so that flue gas entering from the flue gas inlet at least penetrates through one bearing monomer and then flows out from the flue gas outlet. According to the utility model, the one-time investment is lowest, the construction of a reconstruction site can be quickly completed, and the production continuity is hardly influenced.

Description

Technical Field

[0001] The utility model relates to the technical field of denitration, in particular to an ammonia-free denitration system based on SCR system transformation. Background Art

[0002] According to environmental protection regulations, nitrogen oxides in flue gas generated by various furnaces in related industries (including but not limited to the steel industry, coking industry, and power industry) need to be removed, so a denitrification system is required. Denitrification methods include SCR (selective catalytic reduction) technology, SNCR (selective non-catalytic reduction) technology, PNCR (polymer denitrification) technology, ozone oxidation denitrification, and fixed-bed dry denitrification. Among them, SNCR technology and PNCR technology are rarely used because of their low denitrification efficiency and difficulty in controlling ammonia escape, or even if they are used, they are used in conjunction with SCR technology; ozone oxidation denitrification is not recommended in environmental protection requirements because it involves ozone escape problems, and there are few actual applications; fixed-bed dry ammonia-free denitrification is a process route that has been applied recently. The entire denitrification process does not require ammonia water, which solves the problem of ammonia water transportation and storage. At the same time, the required reaction temperature is reduced, which also reduces the operating cost accordingly, but the current actual application is relatively small; most furnaces currently use the more efficient SCR technology.

[0003] The denitrification agent of SCR technology is ammonia water. NOx in the flue gas reacts with ammonia under the action of the catalyst (2-1), (2-2) and (2-3), and NOx is finally discharged in the form of N2.

[0004] 4NO+4NH3+O2 → 4N2+6H2O (2-1)

[0005] NO+NO2+2NH3 → 3H2O+2N2 (2-2)

[0006] 6NO+4NH3→5N2+6H2O (2-3)

[0007] The denitration system based on SCR technology includes a denitration tower, an ammonia water tank, a hot blast furnace and a catalyst module. The front end of the denitration tower is provided with an air inlet duct, and the rear end is provided with an air outlet duct. The air inlet of the air inlet duct is connected to the kiln, and the air inlet duct is connected to the ammonia water tank and the hot blast furnace. The denitration tower has a built-in catalyst module, and the air outlet duct is connected to the chimney through an induced draft fan. During operation, ammonia water and compressed air are mixed and atomized, and the atomized ammonia water passes through the catalyst module together with the flue gas, during which the above reactions (2-1), (2-2) and (2-3) occur. Since SCR technology requires an ammonia storage and delivery system, and ammonia is a toxic and irritating substance and a hazardous substance, ammonia leakage to the air is likely to occur in many links such as storage and delivery, leading to environmental pollution. The cost of improving the storage and delivery system remains high. In addition, during the catalytic reaction of nitrogen oxides, the injection amount of ammonia needs to be precisely controlled. Due to stability problems of the denitrification system or catalyst performance problems, ammonia escape problems often occur (i.e., a large amount of ammonia is injected, and ammonia that does not participate in the reaction is discharged into the atmosphere with the flue gas). Therefore, whether from the perspective of safety or from the perspective of air pollution control, the use of ammonia brings great potential risks.

[0008] One way to solve a series of problems caused by ammonia water is to use ammonia-free denitrification agent for denitrification. If the denitrification system based on SCR technology is dismantled and a denitrification system based on ammonia-free denitrification agent is established (such as the fixed bed dry denitrification system mentioned above), the cost is high. In addition, since SCR technology is widely used in furnace flue gas treatment, such a transformation will lead to too high a comprehensive social cost and serious waste of resources, and will also have a great impact on the continuity of production. Utility Model Content

[0009] One of the purposes of the utility model is to transform the SCR system at a relatively low cost with little impact on the continuity of production, and at the same time fundamentally solve the problems of leakage, escape and high storage and transportation costs caused by ammonia water in the SCR system, so as to achieve the effect of ammonia-free denitrification of flue gas. To this end, the utility model provides an ammonia-free denitrification system based on the transformation of the SCR system.

[0010] In order to achieve the above-mentioned purpose, the utility model provides the following technical solution.

[0011] An ammonia-free denitrification system based on the transformation of an SCR system, the ammonia-free denitrification system includes a denitrification tower in the original SCR system, the upper part of the denitrification tower is provided with a smoke inlet, the lower part is provided with a smoke outlet, and the interior has a placement space originally used for placing a catalyst, the ammonia-free denitrification system also includes a supporting monomer for containing an ammonia-free denitrification agent, the supporting monomer includes a monomer enclosure structure and a porous bottom plate, the upper end of the monomer enclosure structure is open, and the lower end is connected to the porous bottom plate, and the supporting monomer and the porous bottom plate form a holding space for holding the ammonia-free denitrification agent, a plurality of flue gas diversion holes are provided on the porous bottom plate, and the flue gas diversion holes are configured to prevent the smallest unit of ammonia-free denitrification agent from passing through; a plurality of the supporting monomers are detachably distributed in the placement space, and the supporting monomers cover the transverse section of the denitrification tower, so that the flue gas entering from the smoke inlet passes through at least one of the supporting monomers and then flows out from the smoke outlet.

[0012] As an optional solution, the porous bottom plate includes an edge portion and an opening portion, the edge portion is in a square ring shape and is connected to the single body enclosure structure, and the edge of the opening portion is connected to the inner edge of the edge portion.

[0013] As an optional solution, a plurality of the smoke guide holes form a hole unit, and in the length direction of the porous bottom plate, the hole unit is arranged at equal intervals from one end of the opening portion to the other end according to a first preset value, and in the width direction of the porous bottom plate, the hole unit is arranged at equal intervals from one end of the opening portion to the other end according to a second preset value; in the hole unit, the distance between two adjacent smoke guide holes is less than the first preset value and the second preset value;

[0014] In the length direction of the porous bottom plate, the first preset value is smaller than the length of the hole unit, and in the width direction of the porous bottom plate, the second preset value is smaller than the width of the hole unit;

[0015] As an optional solution, the hole unit includes three groups, the groups are arranged at equal intervals in the width direction of the porous bottom plate, and the spacing between adjacent groups is greater than the width of the smoke guide hole and smaller than the width of the group;

[0016] In each group, the smoke diversion holes are evenly spaced in the length direction to form four rows, and the spacing between adjacent smoke diversion holes is greater than the length of the smoke diversion holes themselves. The smoke diversion holes are evenly spaced in the width direction to form three rows, and the spacing between adjacent smoke diversion holes is less than the width of the smoke diversion holes themselves.

[0017] As an optional solution, the smoke guide holes are waist-shaped holes.

[0018] As an optional solution, the single enclosure structure includes a plurality of baffles, which are sequentially connected and enclosed;

[0019] The single body enclosure structure further includes transverse reinforcing ribs and vertical reinforcing ribs. The transverse reinforcing ribs are connected to the upper end of the baffle, and the two ends of the vertical reinforcing ribs are respectively connected to the transverse reinforcing ribs and the porous bottom plate.

[0020] As an optional solution, multiple load-bearing monomers form a load-bearing unit, the height of the load-bearing unit is the same as the height of a catalyst containing unit in the original SCR system, and multiple load-bearing units are horizontally arranged to form a load-bearing module. Multiple load-bearing modules distributed vertically are arranged in the denitrification tower, and there is a spacing between adjacent load-bearing modules.

[0021] As an optional solution, the load-bearing unit includes a unit enclosure structure, the interior of the unit enclosure structure isolates a placement area, and one load-bearing monomer is arranged in the placement area or a plurality of load-bearing monomers are stacked.

[0022] As an optional solution, the unit enclosure structure includes a frame and a enclosure, the frame isolates the placement area, the frame supports the load-bearing unit at the lower end of the placement area, and the enclosure surrounds and is fixed on all sides of the frame.

[0023] As an optional solution, a plurality of the supporting monomers are stacked up and down to form a supporting unit, and the ammonia-free denitrification agent is configured as a block-shaped honeycomb structure with a plurality of vertical holes, and multiple layers of ammonia-free denitrification agent are stacked in the supporting monomer, and a plurality of blocks of ammonia-free denitrification agent in each layer are closely arranged and cover the supporting monomer.

[0024] The utility model has at least the following beneficial effects:

[0025] The denitrification tower uses the equipment in the original SCR system, and the catalyst in the placement space is replaced with an ammonia-free denitrification agent. Since the catalyst is made of alumina and other materials as the base material, and elements such as vanadium and titanium are added, its essential principle is to play a catalytic role, allowing ammonia water and nitrogen oxides to react to produce nitrogen and water. The catalyst in the chemical reaction will not be consumed, but its activity will continue to decrease, and its replacement frequency is relatively low. The ammonia-free denitrification agent directly participates in the chemical reaction, and while solidifying and eliminating nitrogen oxides, it is constantly consumed until the reaction is exhausted and ends. Its replacement frequency is also high. In addition, the catalyst is usually a block structure with holes, and the flow direction of the flue gas is controlled by these holes, while the existing ammonia-free denitrification agent is granular. These factors make the existing device for holding the catalyst unable to be used to load the ammonia-free denitrification agent.

[0026] The utility model designs a bearing monomer to accommodate the ammonia-free denitrifier, wherein the monomer enclosure structure constrains the ammonia-free denitrifier from the side, and the porous bottom plate constrains the ammonia-free denitrifier from the bottom. The granular ammonia-free denitrifier is stacked in the holding space to generate porosity, but the flow direction of the smoke is chaotic. The porous bottom plate is provided with smoke diversion holes to divert the smoke and control the smoke to flow in the set direction, so that the smoke can flow evenly to the next bearing monomer or smoke outlet. The porous bottom plate can use CFD (computational fluid dynamics) simulation to simulate the flow field dynamics, and determine the arrangement and size of the smoke diversion holes in combination with the size of the ammonia-free denitrifier. Arranging multiple bearing monomers in the placement space can accurately understand and replace the failed ammonia-free denitrifier. There is no need to connect the ammonia tank and hot air furnace to the air inlet duct at the front end of the desulfurization tower. The ammonia tank and hot air furnace in the original SCR system can be directly removed, thereby solving the problems of leakage, escape, and high storage and transportation costs caused by ammonia. The cost of the solution is much lower than the cost of dismantling the SCR system and establishing a fixed-bed dry denitrification system.

[0027] The utility model has the lowest one-time investment and can quickly complete the construction of the transformation site, with almost no influence on the continuity of production.

[0028] The catalyst in the SCR technology has high requirements for temperature, and a hot air furnace needs to be installed, resulting in high operating costs. The utility model transforms the SCR system into an ammonia-free denitrification system, which has lower temperature requirements, thereby reducing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The technical features and advantages of the present invention may be more fully understood by referring to the following detailed description in conjunction with the accompanying drawings.

[0030] Figure 1 This is a schematic diagram of an ammonia-free denitrification system based on SCR system modification according to an embodiment of the utility model.

[0031] Figure 2 It is a schematic diagram of a carrying unit in a top view according to an embodiment of the present invention.

[0032] Figure 3 It is a cross-sectional view of a load-bearing unit in a front view state according to an embodiment of the present invention.

[0033] Figure 4 It is a cross-sectional view of a load-bearing unit in a top view according to an embodiment of the present invention.

[0034] Figure 5 It is a cross-sectional view of a load-bearing unit in a left-side state according to an embodiment of the present invention.

[0035] Figure 6 This is a front view of a load-bearing unit according to another embodiment of the present invention.

[0036] Figure 7 It is a schematic diagram of a carrier unit of another embodiment of the utility model, wherein the arrangement of the ammonia-free denitrification agent is illustrated in the uppermost carrier unit.

[0037] Reference numerals:

[0038] 1. Denitrification tower; 11. Smoke inlet; 12. Smoke outlet; 2. Smoke inlet duct; 21. Smoke inlet control valve; 3. Smoke outlet duct; 31. Smoke outlet control valve; 4. Load-bearing unit; 41. Unit enclosure structure; 42. Porous bottom plate; 421. Smoke diversion hole; 422. Edge; 423. Opening; 424. Hole unit; 425. Group; 43. Accommodating space; 45. Support structure; 5. Load-bearing unit; 6. Load-bearing module; 7. Unit enclosure structure; 71. Frame; 8. Chimney. DETAILED DESCRIPTION

[0039] Unless otherwise defined, the technical terms or scientific terms used in this specification and claims shall have the common meanings understood by persons having ordinary skills in the technical field to which the present invention belongs.

[0040] refer to Figure 1-7 The embodiment of the utility model provides an ammonia-free denitration system based on SCR system modification, which can be modified on the basis of the existing SCR system.

[0041] The ammonia-free denitrification system includes a denitrification tower 1 in the original SCR system, wherein a smoke inlet 11 is provided at the top of the denitrification tower 1, a smoke outlet 12 is provided at the bottom, and a placement space originally used for placing a catalyst is provided inside, wherein the smoke inlet 11 is connected to the furnace through a smoke inlet pipe 2, a smoke inlet control valve 21 is provided on the smoke inlet pipe 2 to control on and off, and the smoke outlet 12 is connected to the chimney 8 through a smoke outlet pipe 3, a smoke outlet control valve 31 is provided on the smoke outlet pipe 3 to control on and off. The ammonia-free denitrification system also includes a supporting monomer 4 for containing the ammonia-free denitrification agent. The supporting monomer 4 includes a monomer enclosure structure 41 and a porous bottom plate 42. The upper end of the monomer enclosure structure 41 is open, and the lower end is connected to the porous bottom plate 42, and together with the porous bottom plate 42, it forms a containing space 43 for containing the ammonia-free denitrification agent. A plurality of flue gas diversion holes 421 are provided on the porous bottom plate 42, and the flue gas diversion holes 421 are configured so that the smallest unit of ammonia-free denitrification agent cannot pass through; a plurality of supporting monomers 4 are detachably distributed in the placement space, and the supporting monomers 4 cover the transverse section of the denitrification tower 1, so that the flue gas entering from the smoke inlet 11 passes through at least one supporting monomer 4 and then flows out from the smoke outlet 12.

[0042] Denitrification tower 1 uses the equipment in the original SCR system, and the catalyst in the placement space is replaced with an ammonia-free denitrification agent. Since the catalyst is alumina as a base material, and elements such as vanadium and titanium are added, its essential principle is to play a catalytic role, allowing ammonia water and nitrogen oxides to react to produce nitrogen and water. The catalyst in the chemical reaction will not be consumed, but its activity will continue to decrease, and its replacement frequency is relatively low. The ammonia-free denitrification agent directly participates in the chemical reaction, and while solidifying and eliminating nitrogen oxides, it is constantly consumed until the reaction is exhausted and ends. Its replacement frequency is also high. In addition, the catalyst is usually a block structure with holes, and the flow direction of the flue gas is controlled by these holes, while the existing ammonia-free denitrification agent is granular. These factors make the existing device for holding the catalyst unable to be used to load the ammonia-free denitrification agent.

[0043] The utility model designs a bearing monomer 4 to accommodate ammonia-free denitrifier, wherein the monomer enclosure structure 41 constrains the ammonia-free denitrifier from the side, and the porous bottom plate 42 constrains the ammonia-free denitrifier from the bottom. The granular ammonia-free denitrifier is stacked in the accommodation space 43 to generate porosity, but the flow direction of the flue gas is chaotic. The porous bottom plate 42 is provided with flue gas diversion holes 421 to divert the flue gas and control the flue gas to flow in the set direction, so that the flue gas can flow evenly to the next bearing monomer 4 or the smoke outlet 12. The porous bottom plate 42 can use CFD (computational fluid dynamics) simulation to simulate the flow field dynamics, and determine the arrangement and size of the flue gas diversion holes 421 in combination with the size of the ammonia-free denitrifier. Arranging multiple bearing monomers 4 in the placement space can accurately understand and replace the failed ammonia-free denitrifier. There is no need to connect the ammonia tank and hot air furnace to the air inlet duct at the front end of the desulfurization tower. The ammonia tank and hot air furnace in the original SCR system can be directly removed, thereby solving the problems of leakage, escape, and high storage and transportation costs caused by ammonia. The cost of the solution is much lower than the cost of dismantling the SCR system and establishing a fixed-bed dry denitrification system.

[0044] It should be noted that ammonia-free denitrifiers are usually used in fixed-bed dry denitrification technology and are arranged on the bed layer in a granular form. If only the external structure of the ammonia-free denitrifier is changed to the porous block structure of the above-mentioned catalyst without improving the supporting monomer 4, the agent supplier will need to improve the agent production line. Compared with the solution of improving the agent production line, this solution allows enterprises with SCR denitrification treatment systems to quickly improve the denitrification system and directly purchase existing ammonia-free denitrifiers without waiting for the agent supplier to cooperate with the improvement. This solution has almost no impact on the continuity of production and has the lowest one-time investment.

[0045] like Figure 4As shown, the porous bottom plate 42 includes an edge portion 422 and an opening portion 423. The edge portion 422 is a square ring, and is used to be fixedly connected to the lower end of the single enclosure structure 41. The edge portion 422 and the single enclosure structure 41 can be connected by welding, clamping or fastener fixing. The edge of the opening portion 423 is connected to the inner edge of the edge portion 422; Figure 4 The dotted line in the figure indicates the critical line between the edge portion 422 and the opening portion 423, so as to distinguish between the two. In actual application, the edge portion 422 and the opening portion 423 can be formed in one piece, and the critical line does not exist. In this solution, by setting the edge portion 422 and the opening portion 423, the area connected to the single enclosure structure 41 and the area of ​​the opening are distinguished, which is equivalent to that except for the edge position of the porous bottom plate 42, all other positions are covered with flue gas diversion holes 421, or it can be understood that the area on the porous bottom plate 42 facing the ammonia-free denitrification agent is covered with flue gas diversion holes 421, thereby maximizing the opening area, the flue gas is evenly diverted, and the flue gas velocity flowing out of the flue gas diversion holes 421 is also relatively slow.

[0046] Continue to refer Figure 4 The smoke guide hole 421 is a waist-shaped hole, that is, a hole with a semicircular structure at both ends. A plurality of smoke guide holes 421 form a hole unit 424. Figure 4 The dotted line frame in the figure shows the existence of a single hole unit 424, which does not actually exist. Figure 4 In the X direction shown, the hole units 424 are arranged at equal intervals from one end of the opening portion 423 to the other end according to a first preset value, and the first preset value is smaller than the length of the hole units 424. In the width direction of the porous bottom plate 42, that is, Figure 4 In the Y direction shown, the hole units 424 are arranged at equal intervals from one end of the opening portion 423 to the other end according to a second preset value, and the second preset value is smaller than the width of the hole unit 424. In the hole unit 424, the spacing between two adjacent smoke guide holes 421 in the X direction is smaller than the first preset value and the second preset value, and is smaller than the length of a single smoke guide hole 421, and the spacing between two adjacent smoke guide holes 421 in the Y direction is smaller than the first preset value and the second preset value.

[0047] The hole unit 424 can be further sub-grouped, such as Figure 4 As shown, the hole unit 424 includes three groups 425, which are arranged at equal intervals in the Y direction, and the intervals between adjacent groups 425 are greater than the width of the smoke guide hole 421, and smaller than the width of the group 425. In each group 425, the X direction is evenly spaced and formed into four columns, and the intervals between adjacent smoke guide holes 421 are smaller than the length of the smoke guide hole 421 itself, and the Y direction is evenly spaced and formed into three rows, and the intervals between adjacent smoke guide holes 421 are smaller than the width of the smoke guide hole 421 itself. Figure 4This arrangement method is the best solution finally selected through CFD (computational fluid dynamics) simulation to simulate the flow field dynamics among multiple arrangement schemes. From the simulation effect, the porous bottom plate 42 not only realizes uniform airflow distribution and prevents deviation, but also avoids clogging of holes, which is conducive to the falling of dust.

[0048] In the embodiment of the utility model, the monomer enclosure structure 41 includes a plurality of baffles, which are connected and enclosed in sequence, that is, four baffles are connected end to end to form a structure with two ends open, and the lower end of the baffle is fixedly connected to the edge 422 of the porous bottom plate 42. The monomer enclosure structure 41 also includes transverse reinforcement ribs and vertical reinforcement ribs, the transverse reinforcement ribs are connected to the upper end of the baffle, and the two ends of the vertical reinforcement ribs are respectively connected to the transverse reinforcement ribs and the porous bottom plate 42. The baffle can better restrain the denitrification agent, and the transverse reinforcement ribs and the vertical reinforcement ribs increase the rigidity of the baffle, thereby improving the reliability of the load-bearing monomer 4.

[0049] The structure of the supporting monomer 4 is described in detail above. Next, the arrangement of the supporting monomer 4 in the denitration tower 1 will be specifically described.

[0050] like Figure 1 As shown, a plurality of bearing monomers 4 form a bearing unit 5, and a plurality of bearing units 5 are arranged horizontally to form a bearing module 6 (eg, Figure 1 The height of the carrier unit 5 is the same as the height of a catalyst containing unit in the original SCR system. The size of the cross section of the carrier unit 5 can also be further set to be close to the size of the containing unit, that is, the space occupied by the carrier unit 5 is close to the space occupied by the containing unit. Therefore, the carrier unit 5 can be directly arranged by borrowing the arrangement method of the containing unit, and the transformation cost can be further reduced. A plurality of carrier modules 6 distributed up and down are arranged in the denitrification tower 1, and a spacing is provided between the carrier modules 6. The carrier module 6 can be pre-set, and the carrier module 6 can be used as a unit during transportation and placement in the denitrification tower 1, which improves the transportation efficiency and saves the time for replacing the denitrification agent in the denitrification tower 1. The denitrification agent is a consumable. The upper denitrification agent contacts the flue gas first and is consumed faster than the lower denitrification agent. After multiple layers of carrier modules 6 are arranged in the upper and lower directions, the upper carrier modules 6 can be replaced regularly first, so that the utilization rate of the denitrification agent can be improved and sufficient denitrification can be achieved. A gap is set between adjacent supporting modules 6, and the smoke is further mixed in the gap before entering the supporting module 6 below, so that the smoke can react more evenly and fully.

[0051] like Figure 2 As shown, in some embodiments, the load-bearing unit 5 includes a unit enclosure structure 7, and a placement area is isolated inside the unit enclosure structure 7. A load-bearing monomer 4 is arranged in the placement area, or a plurality of load-bearing monomers 4 are stacked. Figure 2Each placement area is indicated by crossed diagonal lines where a load-bearing unit 4 is placed, for ease of understanding. By setting up a unit enclosure structure 7, multiple load-bearing units 4 are firmly gathered together to facilitate overall replacement. The unit enclosure structure 7 includes a frame 71 and a panel. The frame 71 is formed by cross-fixing a number of horizontal beams and vertical beams. The horizontal beams and vertical beams are made of steel sections. The frame 71 isolates the placement area. The size of the placement area formed by the steel sections is adapted to the load-bearing unit 4, and the frame 71 supports the edge of the load-bearing unit 4 at the bottom of the placement area; the panel surrounds the frame 71, and the panel surrounds the frame 71 from all sides. The manufacturer can store the load-bearing unit 5 on its side, and place a pallet or wooden strips under the panel below to facilitate forklifts to lift and carry it.

[0052] like Figure 6 and Figure 7 As shown, in some other embodiments, the edge of the porous bottom plate 42 of the bearing monomer 4 extends outward relative to the monomer enclosure structure 41, and the extended portion can be stably seated on the upper end of another bearing monomer 4. The porous bottom plate 42 and the monomer enclosure structure 41 are welded and fixed from the outside, and a support structure 45 extending outward is welded to the upper end of the monomer enclosure structure 41, so as to more stably support the upper bearing monomer 4. In this embodiment, three bearing monomers 4 are stacked up and down to form a bearing unit 5, and the lower bearing monomer 4 supports the upper bearing monomer 4. The ammonia-free denitrifier is configured as a block-shaped honeycomb structure with a plurality of vertical holes. Multiple layers of ammonia-free denitrifier are stacked in the bearing monomer 4, and a plurality of ammonia-free denitrifiers in each layer are closely arranged and covered with the bearing monomer 4. Figure 7 The diagram shows a situation of three rows and six columns. In actual application, the number of loads of a single load-bearing unit 4 can be adjusted according to demand. Compared with the catalyst holding unit in the original SCR system, the utility model not only improves the structure of the load-bearing unit 4, but also divides it in height. The denitrification agent in the top load-bearing unit 4 reacts with the flue gas first and is consumed quickly. In this solution, the system efficiency can be improved by timely replacing the top load-bearing unit 4. Compared with the above-mentioned replacement of the entire load-bearing unit 5 on the top layer, the height of the load-bearing unit 4 is less than the height of the load-bearing unit 5. This solution can more accurately replace the first failed part, which not only improves the system efficiency, but also allows the denitrification agent to fully react.

[0053] It should be noted that Figure 2 The embodiments shown and Figure 6 , 7 In the illustrated embodiment, another difference between the supporting units 4 is that the latter is larger than the former. For example, taking the X-direction dimension of the porous bottom plate 42 as an example, the latter may be more than twice the former.

[0054] In addition, the terms "first", "second", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, a feature defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present utility model, unless otherwise specified, "plurality" means two or more.

[0055] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-restrictive from any point of view, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention. Any reference numeral in a claim should not be regarded as limiting the claim to which it relates.

Claims

1. An ammonia-free denitration system based on the transformation of the SCR system, the ammonia-free denitration system comprises a denitration tower in the original SCR system, the upper part of the denitration tower is provided with a smoke inlet, the lower part is provided with a smoke outlet, and the interior has a placement space originally used for placing a catalyst, characterized in that: The ammonia-free denitrification system further includes a load-bearing monomer for containing the ammonia-free denitrification agent, the load-bearing monomer includes a monomer enclosure structure and a porous bottom plate, the upper end of the monomer enclosure structure is open, and the lower end is connected to the porous bottom plate, and the monomer enclosure structure and the porous bottom plate enclose a storage space for accommodating the ammonia-free denitrification agent, and the porous bottom plate is provided with a plurality of flue gas diversion holes, and the flue gas diversion holes are set to prevent the smallest unit of the ammonia-free denitrification agent from passing through; A plurality of the supporting monomers are detachably distributed in the placement space, and the supporting monomers cover the entire transverse section of the denitration tower, so that the flue gas entering from the smoke inlet passes through at least one of the supporting monomers and then flows out from the smoke outlet.

2. The ammonia-free denitrification system based on SCR system transformation according to claim 1 is characterized in that: The porous bottom plate comprises an edge portion and an opening portion, wherein the edge portion is in a square ring shape and is connected to the single body enclosure structure, and the edge of the opening portion is connected to the inner edge of the edge portion.

3. The ammonia-free denitrification system based on SCR system transformation according to claim 2 is characterized in that: A plurality of the smoke guide holes form a hole unit. In the length direction of the porous bottom plate, the hole unit is arranged at equal intervals from one end of the opening portion to the other end according to a first preset value. In the width direction of the porous bottom plate, the hole unit is arranged at equal intervals from one end of the opening portion to the other end according to a second preset value. In the hole unit, the distance between two adjacent smoke guide holes is less than the first preset value and the second preset value. In the length direction of the porous bottom plate, the first preset value is smaller than the length of the hole unit, and in the width direction of the porous bottom plate, the second preset value is smaller than the width of the hole unit.

4. The ammonia-free denitrification system based on SCR system transformation according to claim 3 is characterized in that: The hole unit includes three groups, and the groups are arranged at equal intervals in the width direction of the porous bottom plate, and the interval between adjacent groups is greater than the width of the smoke guide hole and smaller than the width of the group; In each group, the smoke diversion holes are evenly spaced in the length direction to form four rows, and the spacing between adjacent smoke diversion holes is greater than the length of the smoke diversion holes themselves. The smoke diversion holes are evenly spaced in the width direction to form three rows, and the spacing between adjacent smoke diversion holes is less than the width of the smoke diversion holes themselves.

5. The ammonia-free denitrification system based on SCR system transformation according to claim 1 is characterized in that: The smoke guide hole is a waist-shaped hole.

6. The ammonia-free denitrification system based on SCR system transformation according to claim 1 is characterized in that: The single enclosure structure includes a plurality of baffles, which are sequentially connected and enclosed; The single body enclosure structure further includes transverse reinforcing ribs and vertical reinforcing ribs. The transverse reinforcing ribs are connected to the upper end of the baffle, and the two ends of the vertical reinforcing ribs are respectively connected to the transverse reinforcing ribs and the porous bottom plate.

7. The ammonia-free denitrification system based on SCR system transformation according to any one of claims 1 to 6, characterized in that: A plurality of load-bearing monomers form a load-bearing unit, the height of the load-bearing unit is the same as the height of a catalyst containing unit in the original SCR system, and a plurality of load-bearing units are horizontally arranged to form a load-bearing module. A plurality of the load-bearing modules distributed vertically are arranged in the denitrification tower, and a spacing is provided between adjacent load-bearing modules.

8. The ammonia-free denitrification system based on SCR system transformation according to claim 7 is characterized in that: The load-bearing unit comprises a unit enclosure structure, wherein a placement area is isolated inside the unit enclosure structure, and one load-bearing monomer is arranged in the placement area or a plurality of load-bearing monomers are stacked.

9. The ammonia-free denitrification system based on SCR system transformation according to claim 8 is characterized in that: The unit enclosure structure includes a frame and a enclosure plate. The frame isolates the placement area. The frame supports the load-bearing unit at the lower end of the placement area. The enclosure plate surrounds and is fixed on all sides of the frame.

10. The ammonia-free denitrification system based on SCR system transformation according to claim 7, characterized in that: A plurality of the supporting monomers are stacked up and down to form a supporting unit, and the ammonia-free denitrifier is configured as a block-shaped honeycomb structure with a plurality of vertical holes. Multiple layers of ammonia-free denitrifier are stacked in the supporting monomer, and a plurality of ammonia-free denitrifier blocks are closely arranged in each layer and cover the entire supporting monomer.

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