Flow guiding, ammonia spraying and mixing integrated device and denitration system

Abstract

The invention relates to a flow guiding, ammonia spraying and mixing integrated device and a denitration system.The flow guiding, ammonia spraying and mixing integrated device comprises an ammonia spraying part, a mixing part and at least one flow guiding unit, and flow guiding channels are formed in the two sides of each flow guiding unit correspondingly; the flow guide unit comprises a mounting cavity, and an ammonia spraying part is mounted in the mounting cavity; the mixing part is arranged at the rear end of the flow guide unit, the side wall of the mounting cavity is further provided with ammonia spraying pieces communicating the ammonia spraying part with the flow guide channels, the mixing part comprises mixing pieces in one-to-one correspondence with the flow guide channels, and the mixing pieces are fixedly arranged at the rear end of the flow guide unit. The flow guiding, ammonia spraying and mixing integrated device integrates flow guiding, ammonia spraying and mixing, the mixing path of flue gas and reducing agent ammonia can be effectively prolonged, the mixing uniformity is improved, the flue gas denitration efficiency is further improved, meanwhile, the system resistance can be reduced, and the system operation cost can be reduced.

Description

Technical Field

[0001] The present application relates to the technical field of denitration equipment, and in particular to an integrated device for diversion, ammonia injection and mixing and a denitration system. Background Art

[0002] Selective catalytic reduction (SCR) denitrification technology is the most mature flue gas denitrification technology. It has the advantages of simple device structure, good reliability, stable operation, etc., and is widely used. The principle of SCR denitrification process is to spray the reducing agent ammonia (ammonia gas or ammonia water) into the flue gas containing nitrogen oxides. After a certain degree of mixing, the reducing agent ammonia and nitrogen oxides undergo redox reaction under the action of the catalyst, so that the nitrogen oxides are reduced to harmless nitrogen and water.

[0003] Although SCR denitrification has the advantages of simple structure, good reliability and stable operation, it also has problems such as difficulty in uniform mixing of ammonia and nitrogen, high ammonia escape rate and large local resistance. When the reducing agent ammonia and nitrogen oxides are not mixed evenly, there will be a lack of ammonia locally, and the corresponding denitrification efficiency will be reduced. When the resistance of the denitrification system is too large, the system operation cost will increase.

[0004] How to improve the flue gas denitrification efficiency and reduce the system operating costs is a technical problem that technical personnel in this field urgently need to solve. Summary of the invention

[0005] The purpose of the present application is to provide an integrated device for diversion, ammonia injection and mixing and a denitrification system. The integrated device for diversion, ammonia injection and mixing integrates diversion, ammonia injection and mixing into one, which can effectively extend the mixing path of flue gas and reducing agent ammonia, improve the mixing uniformity, and thus improve the flue gas denitrification efficiency. At the same time, it can also reduce system resistance and reduce system operating costs.

[0006] In order to solve the above-mentioned technical problems, the present application provides an integrated device for guiding, spraying ammonia and mixing, comprising an ammonia spraying part, a mixing part and at least one guiding unit, wherein guiding channels are respectively formed on both sides of the guiding unit; the guiding unit comprises an installation cavity, in which the ammonia spraying part is installed; the mixing part is arranged at the rear end of the guiding unit, and the side wall of the installation cavity is also provided with an ammonia spraying part connecting the ammonia spraying part and the guiding channel, and the mixing part comprises mixing parts corresponding to each of the guiding channels one by one, and the mixing parts are fixedly arranged at the rear end of the guiding unit.

[0007] The guide unit has an installation cavity, and the ammonia spray part is arranged in the installation cavity, and only the ammonia spray part connected with the ammonia spray part extends out of the guide unit to spray ammonia into the corresponding guide channel. In this way, the guide unit can provide guidance for the flue gas while providing protection for the ammonia spray part. Compared with the solution of directly arranging the ammonia spray part in the flue, the local pressure loss caused by the flue gas flowing through the ammonia spray part can be reduced. At the same time, the problem of the ammonia spray part being eroded and worn by dust in the flue can be effectively avoided. The wear-resistant angle steel and other components for protecting the ammonia spray part are eliminated, the overall structure is simplified and the construction cost can be effectively reduced.

[0008] The resistance encountered by the flue gas when flowing in the flue is mainly caused by two reasons: internal friction and vortex, and the local resistance caused by the vortex is the main source of resistance. The setting of the guide unit allows the flue gas to flow from front to back along the flue, and when passing through the bend, it can pass through each guide channel respectively. The guide unit guides the flue gas at the bend, which can reduce or eliminate the vortex generated by the flue gas due to the turn, which can make the flue gas flow evenly and reduce the local pressure loss. In addition, since the guide unit is provided with an installation cavity, the guide unit has a larger thickness than the traditional plate-type guide, which can greatly reduce the vortex area on the leeward side, which is conducive to reducing local pressure loss and thus reducing the system operation cost.

[0009] In addition, a mixing section is provided at the rear end of the guide unit, and each guide channel has a corresponding mixing element, which is used to mix the reducing agent ammonia and the flue gas sprayed into the guide channel by the ammonia spray element to ensure that the flue gas and the reducing agent ammonia are evenly mixed. The mixing section is provided at the rear end of the guide unit, and the guide unit forms a supporting component for the mixing element, thereby simplifying the overall structure of the mixing section. During installation, the guide unit, the ammonia spray section and the mixing section are first integrated into an integrated component, and then the integrated component is installed in the flue as a whole, which can simplify the overall structure and installation operation.

[0010] In addition, the mixing unit is integrated into the integrated device of flow diversion, ammonia spraying and mixing. Under the condition of the same flue length, the flue length between the mixing unit and the catalyst can be made longer. After the ammonia spraying unit sprays the reducing agent ammonia into the flow diversion channel through the ammonia spraying part, it is directly mixed with the flue gas through the mixing unit when it flows out of the flow diversion channel. The flue gas can be mixed with the reducing agent ammonia earlier, and then reach the catalyst through a longer flue, and the mixing uniformity is better. In addition, the blades of the mixing unit cooperate with the flow diversion unit, and the more uniform flow field is conducive to more accurate control of the mixing of the reducing agent ammonia and the flue gas.

[0011] Moreover, the ammonia spraying part is arranged with the guide unit at the first turning part near the inlet side of the flue. Compared with the scheme of setting the ammonia spraying part in the vertical section, the distance from the catalyst is farther. In this way, the mixing distance of the reducing agent ammonia sprayed into the guide channel and the flue gas before the reaction is longer and the mixing uniformity is better, thereby ensuring the denitrification efficiency.

[0012] Optionally, the ammonia spraying component comprises a plurality of ammonia spraying pipes arranged at intervals along the width direction of the guide unit, each of the ammonia spraying pipes is respectively connected to the ammonia spraying part; the guide unit has at least two ammonia spraying components arranged at intervals along the length direction, and the ammonia spraying pipes of different ammonia spraying components have different lengths.

[0013] Optionally, the guide unit includes an arc segment and a straight segment along the length direction, the straight segment is arranged at the rear end of the arc segment, the radius of the arc segment located on the outside is greater than the radius of the arc segment located on the inside, and the length of the straight segment located on the outside is greater than the length of the straight segment located on the inside.

[0014] Optionally, the ammonia spraying portion is arranged in the straight line segment;

[0015] And / or, the rear ends of the straight line segments are all sharp-angle structures;

[0016] And / or, the thickness of the front end of the arc segment is smaller than the thickness of the rear end of the arc segment.

[0017] Optionally, the mixing element comprises a plurality of blades spaced apart along the width direction of the guide unit, the rear ends of the blades are inclined toward one side of the guide channel, and the inclination directions of the blades of two adjacent mixing elements are opposite.

[0018] Optionally, the blades of two adjacent mixing elements are staggered in sequence along the width direction of the guide unit.

[0019] Optionally, at least one of the flow guide units includes a first flow guide unit, and the first flow guide unit is fixed with two of the mixing elements.

[0020] Optionally, when there are multiple guide units, the multiple guide units include a second guide unit and / or a third guide unit; the second guide unit is fixed with a mixing piece and is located at the outermost or innermost side; the third guide unit is not connected to the mixing piece, and the third guide unit and the first guide unit are arranged in an staggered manner.

[0021] Optionally, the ammonia injection pipe is provided corresponding to the front side of the blade, and the projection of the axis of the ammonia injection pipe corresponding to the blade on the blade coincides with the center line of the blade.

[0022] The present application also provides a denitrification system, comprising a flue, and an integrated device for guiding, spraying ammonia and mixing as described in any one of claims 1 to 4; the flue comprises a turning portion, and the integrated device for guiding, spraying ammonia and mixing is arranged in the turning portion.

[0023] The technical effect of the denitrification system having the integrated diversion, ammonia injection and mixing device as described above is similar to the technical effect of the integrated diversion, ammonia injection and mixing device as described above, and will not be repeated here to save space. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a structural schematic diagram of a denitration system provided in an embodiment of the present application;

[0025] Figure 2 yes Figure 1 A partial enlarged view of the

[0026] Figure 3 yes Figure 2 Schematic diagram of the structure of the integrated device for central diversion, ammonia injection and mixing;

[0027] Figure 4 yes Figure 2 A top view of

[0028] Figure 5 is a top view of the guide unit and the mixing section;

[0029] Figure 6 It is a three-dimensional structural schematic diagram of the denitrification system;

[0030] Figure 7 It is a dimensional diagram of the mixing distance in the simulated experimental denitrification system;

[0031] Figure 8 It is the flue gas velocity distribution diagram in the simulated experimental denitrification system;

[0032] Fig. 9 It is the flow diagram of reducing agent ammonia in the simulated experimental denitrification system;

[0033] Fig.10 It is the flue gas velocity distribution diagram of the flue section upstream of the first layer catalyst in the simulated experimental denitrification system;

[0034] Fig.11 It is the distribution diagram of NH3 / NOx molar ratio in the flue section upstream of the first layer catalyst in the simulated experimental denitration system;

[0035] Fig.12 This is a curve chart showing the change of Cv value of NH3 / NOx molar ratio distribution with mixing distance in the simulation experiment.

[0036] Attached Figure 1-Figure 12 In the figure, the reference numerals are described as follows:

[0037] 10 flow guide, ammonia injection, and mixing integrated device; 20 flue, 201 first horizontal section, 202 vertical section, 203 second horizontal section; 30 flow guide; 40 rectifying grid; 50 catalyst;

[0038] 1 guide unit, 11 guide plate, 12 installation cavity, 13 arc segment, 14 straight segment;

[0039] 2 ammonia spraying parts, 21 ammonia spraying pipes;

[0040] 3 mixing element, 31 first blade, 32 second blade. DETAILED DESCRIPTION

[0041] In order to enable those skilled in the art to better understand the technical solution of the present application, the present application is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0042] An embodiment of the present application provides an integrated device for diversion, ammonia injection and mixing and a denitrification system, wherein the denitrification system includes a flue 20 and an integrated device for diversion, ammonia injection and mixing 10, the flue 20 is provided with a turning portion, and the integrated device for diversion, ammonia injection and mixing 10 is arranged in the turning portion for diverting, injecting ammonia and mixing the flue gas passing through the turning portion.

[0043] Specifically, Figure 1 As shown, the denitration system also includes components such as a rectifying grid 40 and a catalyst 50. The flue 20 includes a first horizontal section 201, a vertical section 202 and a second horizontal section 203 which are connected in sequence, wherein the first horizontal section 201 is arranged on a side close to the entrance of the flue 20, and the second horizontal section 203 is arranged on a side close to the catalyst 50. A first turning portion is formed between the first horizontal section 201 and the vertical section 202, and a second turning portion is formed between the vertical section 202 and the second horizontal section 203. The first turning portion is provided with an integrated device 10 for guiding, spraying ammonia and mixing, and the second turning portion is provided with a guiding member 30. The integrated device 10 for guiding, spraying ammonia and mixing and the guiding member 30 are respectively used to guide the passing flue gas to ensure a stable flow rate of each flue gas in the flue 20.

[0044] like Figure 2As shown, the integrated device 10 for guiding, spraying ammonia and mixing includes an ammonia spraying part, a mixing part and at least one guiding unit 1. The guiding unit 1 includes an installation cavity 12, in which the ammonia spraying part is installed. The mixing part is arranged at the rear end of the guiding unit 1. The side wall of the installation cavity 12 is also provided with an ammonia spraying part 2. The ammonia spraying part 2 is connected between the ammonia spraying part and the guiding channel, and is used to spray the reducing agent ammonia into the guiding channel. The mixing part includes a mixing part 3. The number of the mixing parts 3 is the same as the number of the guiding channels and is arranged one by one. The mixing part 3 is fixed at the rear end of the guiding unit 1. That is to say, the rear end of each guiding channel has a mixing part 3 corresponding thereto. The mixing part 3 is used to mix the reducing agent ammonia and the flue gas sprayed into the guiding channel by the ammonia spraying part 2.

[0045] Herein, “front” refers to the side facing upstream along the flue gas flow direction, and “rear” refers to the side facing downstream along the flue gas flow direction. The width direction of the guide unit 1 is parallel to the width direction of the flue 20 .

[0046] The guide unit 1 includes two guide plates 11, and the two guide plates 11 enclose an installation cavity 12. The guide plates 11 are provided with an ammonia spraying part 2. Of course, the guide unit 1 can also form the installation cavity 12 by processing. The formation of the installation cavity 12 by enclosing two guide plates 11 can simplify the molding process of the guide unit 1.

[0047] The guide unit 1 is arranged in the flue 20, and divides the space in the flue 20 along the thickness direction to form at least two guide channels. When only one guide unit 1 is provided, there are two guide channels. The inner guide plate 11 of the guide unit 1 forms a guide channel with the side wall of the flue, and the outer guide plate 11 of the guide unit 1 forms a guide channel with the side wall of the flue.

[0048] When the number of the guide units 1 is at least two, the guide units 1 are arranged in sequence and side by side in the flue 20 along the thickness direction of the flue 20, and the space in the flue 20 is divided to form a plurality of guide channels, and guide channels are formed between two adjacent guide units 1 and between the guide unit 1 and the inner wall surface of the flue 20, respectively.

[0049] That is to say, in this embodiment, the guide unit 1 has an installation cavity 12, and the ammonia spray part is arranged in the installation cavity 12, and only the ammonia spray part 2 connected with the ammonia spray part extends out of the guide unit 1 to spray ammonia into the corresponding guide channel. In this way, the guide unit 1 can provide guidance for the flue gas while providing protection for the ammonia spray part. Compared with the solution of directly arranging the ammonia spray part in the flue 20, the local pressure loss caused by the flue gas flowing through the ammonia spray part can be reduced. At the same time, the problem of the ammonia spray part being eroded and worn by dust in the flue 20 can be effectively avoided. The anti-wear angle steel and other components for protecting the ammonia spray part are eliminated, the overall structure is simplified and the construction cost can be effectively reduced.

[0050] The resistance encountered by the flue gas when flowing in the flue 20 is mainly caused by two reasons: internal friction and vortex, and the local resistance caused by the vortex is the main source of resistance. The setting of the guide unit 1 allows the flue gas to flow from front to back along the flue 20, and when passing through the first bend, it can pass through each guide channel respectively. The guide unit 1 guides the flue gas at the first bend, which can reduce or eliminate the vortex generated by the flue gas due to the turn, so that the flue gas can flow evenly and reduce the local pressure loss. In addition, since the guide unit 1 is provided with an installation cavity 12, the guide unit 1 has a larger thickness than the traditional plate-type guide, which can greatly reduce the vortex area on the leeward side, which is conducive to reducing local pressure loss and thus reducing the system operation cost.

[0051] In addition, a mixing section is also provided at the rear end of the guide unit 1, and each guide channel has a corresponding mixing element 3, which is used to mix the reducing agent ammonia and the flue gas sprayed into the guide channel by the ammonia spraying element 2 to ensure that the flue gas and the reducing agent ammonia are evenly mixed. The mixing section is provided at the rear end of the guide unit 1, and the guide unit 1 forms a supporting component of the mixing element 3, thereby simplifying the overall structure of the mixing section. During installation, the guide unit 1, the ammonia spraying section and the mixing section are first integrated into an integrated component, and then the integrated component is installed as a whole in the flue 20, which can simplify the overall structure and installation operation.

[0052] In addition, the mixing unit is integrated into the integrated device 10 for guiding, spraying and mixing. Under the condition of the same length of the flue 20, the length of the flue 20 between the mixing unit and the catalyst 50 can be made longer. After the ammonia spraying unit sprays the reducing agent ammonia into the guiding channel through the ammonia spraying part 2, the reducing agent ammonia is directly mixed with the flue gas through the mixing unit when it flows out of the guiding channel. The flue gas can be mixed with the reducing agent ammonia earlier, and then reach the catalyst 50 through the longer flue 20, and the mixing uniformity is better. In addition, the blades of the mixing unit cooperate with the guiding unit 1, and a more uniform flow field is conducive to more accurate control of the mixing of the reducing agent ammonia and the flue gas.

[0053] In addition, the ammonia spraying part is arranged with the guide unit 1 at the first turning part near the inlet side of the flue 20. Compared with the solution of setting the ammonia spraying part in the vertical section 202, the distance from the catalyst 50 is farther. In this way, the mixing distance of the reducing agent ammonia sprayed into the guide channel and the flue gas before the reaction is longer, and the mixing uniformity is better, thereby ensuring the denitrification efficiency.

[0054] Of course, in this embodiment, Figure 1The structure of the denitrification system shown is only an embodiment. The flue 20 may be provided with a plurality of bends. The integrated device for guiding, spraying ammonia and mixing 10 can be provided at one of the plurality of bends provided near the inlet side of the flue 20. The bend where the integrated device for guiding, spraying ammonia and mixing 10 is located can be formed between a horizontal flue and a vertical flue, or between a horizontal flue and an inclined flue, or between an inclined flue and a vertical flue, or between two inclined flues at different angles.

[0055] In the denitrification system provided in the present embodiment, the guide component for guiding the flue gas in the flue 20, the ammonia spraying component for spraying ammonia into the flue gas, and the mixing component for mixing the flue gas and the reducing agent ammonia are integrated into an integrated structure, and the whole is assembled in the first turning part of the flue 20. This can make the overall structure simpler and effectively simplify the disassembly and assembly operations, facilitating subsequent maintenance operations.

[0056] The integrated diversion, ammonia injection and mixing device 10 and the denitrification system provided in this embodiment have important practical application value, can achieve the purpose of improving flue gas denitrification efficiency and reducing operating costs, and are particularly suitable for coal-fired flue gas denitrification projects with short denitrification flues 20 and compact structures.

[0057] The ammonia spraying member 2 includes a plurality of ammonia spraying pipes 21 arranged at intervals along the width direction of the guide unit 1, and each ammonia spraying pipe 21 is connected to the ammonia spraying part. That is to say, each ammonia spraying member 2 sprays reducing agent ammonia (specifically ammonia gas or ammonia water) into the corresponding guide channel through the ammonia spraying pipe 21. Of course, it is also possible to directly open a spray hole on the surface of the guide unit 1, and the ammonia spraying pipe 21 has a certain length. Compared with the solution of spraying reducing agent ammonia through a spray hole provided on the guide plate 11, the reducing agent ammonia can be sprayed into the interior of the guide channel, which is convenient for mixing with the flue gas and improving the mixing uniformity.

[0058] like Figure 2 and Figure 3 As shown, the guide unit 1 includes an arc segment 13 and a straight segment 14 arranged in sequence along the length direction, wherein the straight segment 14 is arranged at the rear end of the arc segment 13, and the straight segment 14 is arranged parallel to the vertical segment 202. The arrangement of the straight segment 14 can guide the smoke so that the smoke can flow in the vertical direction, thereby ensuring the guide effect.

[0059] The arc segments 13 of each guide unit 1 are arranged in parallel at the first turning portion, and the radius of the arc segment 13 located on the outside is greater than the radius of the arc segment 13 located on the inside, wherein the arc segment 13 is provided with a concave side and a convex side, the "inside" refers to the concave side of the arc segment 13, and the "outside" refers to the convex side of the arc segment 13. The radius of the arc segment 13 located on the outside is greater than the radius of the arc segment 13 located on the inside, so as to ensure the uniformity of the smoke when it flows along each guide channel to the vertical segment 202 on the downstream side.

[0060] Specifically, Figure 2 As shown, the flue 20 is provided with a guide, ammonia injection, and mixing integrated device 10 at the first turning portion between the first horizontal section 201 and the vertical section 202 at the entrance. The guide, ammonia injection, and mixing integrated device 10 includes three parallel guide units 1, namely 1a, 1b, and 1c, wherein the guide units 1a, 1b, and 1c are sequentially arranged from the inside to the outside in the flue 20, and the inner cavity of the flue 20 is divided into four guide channels along the thickness direction, namely t1, t2, t3, and t4. Specifically, A guide channel t1 is formed between the guide unit 1a and the inner wall of the flue 20, a guide channel t2 is formed between the guide unit 1a and the guide unit 1b, a guide channel t3 is formed between the guide unit 1b and the guide unit 1c, and a guide channel t4 is formed between the guide unit 1c and the outer wall of the flue 20. Two adjacent guide units 1 are arranged equidistantly, and the dimensions of each guide channel (t1, t2, t3, t4) in the thickness direction of the flue 20 are equal, which are all D. The dimension D of the guide channel is preferably 0.5m-1m.

[0061] like Figure 2 As shown, the radius of the arc segment 13 of the guide units 1a, 1b, 1c is R1, R2, R3 respectively, the radius of the arc segment 13 R1, R2, R3 gradually increases, and the radius of the arc segment 13 is preferably 0.5m-3m. The length of the straight segment 14 of the guide units 1a, 1b, 1c is L1, L2, L3 respectively, the length of the straight segment 14 L1, L2, L3 gradually increases, and the length of the straight segment 14 is preferably 0.5m-3m. Make the smoke flow deviation in each guide channel t1, t2, t3, t4 within the range of -5%~5%.

[0062] The radius of the arc segment 13 and the length of the straight segment 14 can be determined based on flow field simulation.

[0063] like Figure 3As shown, the front end of the arc segment 13 has a sharp angle structure or a rounded angle structure, the thickness of the arc segment 13 gradually increases from front to back, and the thickness of the straight segment 14 is greater than the thickness of the arc segment 13, so that the resistance to the smoke at the first turning portion can be reduced and the diversion effect can be improved. In addition, both guide plates 11 are streamlined structures with smooth surface contours and no angular structures, which can reduce resistance while guiding the smoke.

[0064] The rear end of the straight section 14 is in a pointed structure, and the pointed angle β is no greater than 90°. This arrangement can reduce dust accumulation at the rear end of the straight section 14 .

[0065] The ammonia spraying part is preferably arranged in the straight section 14, and the thickness of the straight section 14 is in the range of 60 mm-100 mm to facilitate the installation of the ammonia spraying part. Of course, the ammonia spraying part can also be arranged in the arc section 13, and no specific limitation is made here. When the ammonia spraying part is arranged in the straight section 14, it can reduce the possibility of dust accumulation in the first horizontal section 201 that buries the ammonia spraying pipe 21, and reduce the probability of blockage of the ammonia spraying pipe 21.

[0066] like Figure 2 and Figure 3 As shown, the inner guide plate 11 of each guide unit 1 is provided with an ammonia spray component 2, and the two side guide plates 11 of the outermost guide unit 1c are respectively provided with an ammonia spray component 2 to ensure that an ammonia spray component 2 is correspondingly provided in each guide channel to ensure that the reducing agent ammonia is sprayed into each guide channel.

[0067] Of course, the guide plates 11 located on the outside of each guide unit 1 may be provided with an ammonia spraying member 2, and the guide plates 11 located on both sides of the innermost guide unit 1a may be provided with an ammonia spraying member 2. Moreover, for the guide unit 1 with the ammonia spraying members 2 on both sides, the ammonia spraying members 2 on both sides are arranged at staggered positions along the airflow direction, so that the structural strength of the guide unit 1 at various locations in the airflow direction can be ensured, and the situation of weak structural strength at local locations can be avoided, and at the same time, the arrangement of the connecting structure between the mounting portion in the mounting cavity 12 and the ammonia spraying member 2 is also facilitated.

[0068] If the integrated device 10 for guiding, spraying and mixing includes only one guiding unit 1, ammonia spraying pipes 21 are respectively arranged on both sides of the guiding unit 1, and the structure is as follows: Figure 3 shown.

[0069] The flow guide unit 1 is provided with at least two ammonia spraying parts 2 arranged at intervals along the length direction (i.e., the airflow direction), and the lengths of the ammonia spraying pipes 21 of the same ammonia spraying part 2 are the same, and the lengths of the ammonia spraying pipes 21 of different ammonia spraying parts 2 are different. In other words, the flow guide unit 1 is provided with at least two rows of ammonia spraying pipes 21 of different lengths along the length direction, and such a configuration enables ammonia to be sprayed at different positions in the flow guide channel, so as to ensure the uniformity of the reducing agent ammonia at each position in the cross-sectional direction of the flow guide channel, and further ensure the uniformity of the mixing of the reducing agent ammonia and the flue gas.

[0070] like Figure 3 As shown, when two ammonia spray components 2 are provided, there are two rows of ammonia spray pipes 21. Of course, the guide unit 1 may also be provided with one, three or more ammonia spray components 2. Compared with the solution with only one ammonia spray component 2, at least two ammonia spray components 2 can further ensure the uniformity of distribution of reducing agent ammonia in the guide channel, thereby ensuring the uniformity of mixing of flue gas and reducing agent ammonia. Compared with the solution with three or more ammonia spray components 2, two ammonia spray components 2 can simplify the overall structure and reduce costs while ensuring the uniformity of mixing of flue gas and reducing agent ammonia.

[0071] Preferably, the spacing between two adjacent ammonia spraying parts 2 along the airflow direction is 100 mm to 400 mm, and the axis of each ammonia spraying pipe 21 is arranged parallel to the first horizontal section 201, that is, arranged perpendicular to the vertical section 202, the length of the shorter ammonia spraying pipe 21 is 120 mm to 180 mm, and the length of the longer ammonia spraying pipe 21 is 350 mm to 420 mm. In the same row of ammonia spraying pipes 21, the spacing between two adjacent ammonia spraying pipes 21 is preferably 400 mm to 500 mm. Such an arrangement makes the injection of reducing agent ammonia in each diversion channel more dispersed, which is more conducive to the uniform distribution of reducing agent ammonia on the entire cross section. The specific number and length of the ammonia spraying pipe 21 can be set according to the size of the diversion channel, and no specific restrictions are made here.

[0072] The guide plate 11 is also provided with a threaded hole connected to the ammonia injection part, and the ammonia injection pipe 21 is threadedly matched with the threaded hole. Such a setting can make the structure simple, facilitate the disassembly and assembly of the ammonia injection pipe 21, facilitate maintenance and replacement, and ensure the sealing of the ammonia injection pipe 21 after installation.

[0073] Of course, in the present embodiment, there is no limitation on the fixing method of the ammonia injection pipe 21. For example, the guide plate 11 may be provided with a through hole, the ammonia injection pipe 21 passes through the through hole, and a sealing welding is performed along the circumference of the ammonia injection pipe 21 between the ammonia injection pipe 21 and the guide plate 11. Alternatively, the ammonia injection pipe 21 is fixed to the ammonia injection part and sealed with the guide plate 11.

[0074] The mixing element 3 includes a plurality of blades arranged at intervals along the width direction of the guide unit 1, such as Figure 3 , Figure 4 and Figure 5 As shown, the rear end of the blade is inclined toward one side of the guide channel, and the number of the mixing elements 3 is the same as the number of the guide channels and is arranged one-to-one. That is, each guide channel has a corresponding group of blades, and the inclination angles of the group of blades are the same, and the inclination directions of the blades of two adjacent mixing elements 3 are opposite, that is, the inclination directions of the blades corresponding to the two adjacent guide channels are opposite.

[0075] For the convenience of explanation, the blades of two adjacent mixing elements 3 are respectively referred to as the first blade 31 and the second blade 32. Figure 4 As shown, the guide channels t1 and t3 are respectively provided with a plurality of first blades 31 at intervals along the width direction of the flue, and the guide channels t2 and t4 are respectively provided with a plurality of second blades 32 at intervals along the width direction of the flue.

[0076] The blades of two adjacent mixing elements 3 are staggered in sequence along the width direction of the guide unit 1, that is, the first blade 31 and the second blade 32 are staggered along the width direction of the guide unit 1, and the angle between the first blade 31 and the guide plate 11 is an obtuse angle, and the angle between the second blade 32 and the guide plate 11 is an obtuse angle.

[0077] After the flue gas flows through the guide channel, it can pass through the blades of the mixing part (including the first blade 31 and the second blade 32) together with the reducing agent ammonia sprayed into the guide channel by the ammonia spraying member 2. Since the blades are arranged at staggered intervals, the passing flue gas and the reducing agent ammonia can be mixed, so that the distribution uniformity of the reducing agent ammonia mixed in the flue gas is better, and then when it flows along the flue 20 to the catalyst 50, the denitrification reaction efficiency can be guaranteed.

[0078] The blade is a flat plate structure, and the shape of the blade can be as follows Figure 4 and Figure 5 The trapezoidal structure shown may also be a semicircular structure, a rectangular structure, a triangular structure, etc., and the shape of the first blade 31 and the shape of the second blade 32 may be the same or different.

[0079] When the integrated device 10 for guiding, spraying and mixing includes only one guiding unit 1, a mixing part is provided at the rear end of the guiding unit 1. The structure of the guiding unit 1 is as follows: Figure 3 As shown, the guide unit 1 is a first guide unit with two mixers 3 fixed at the rear end. By fixing two mixers 3 at the rear end of a first guide unit, it can simultaneously meet the requirement that two guide channels correspond to the mixers 3 respectively, which can simplify the overall structure. Figure 3 As shown, the rear end of the first air guide unit 1 is provided with a first blade 31 and a second blade 32 , and the first blade 31 and the second blade 32 are arranged in a similar figure eight structure.

[0080] When there are two guide units 1, one guide unit 1 is a first guide unit with two mixing pieces 3 fixedly mounted thereon, and the other guide unit 1 is a second guide unit with one mixing piece 3 fixedly mounted thereon. The second guide unit may be located at the inner side or the outer side.

[0081] When the number of the guide units 1 is at least three, if the number of the guide units 1 is an odd number and the number of the guide channels is an even number, at this time, the first guide unit with two mixing elements and the third guide unit without a mixing element are arranged alternately, and the guide units located at the outermost and innermost sides are both the first guide units with two mixing elements, the number of the first guide units is one more than the number of the third guide units, and the second guide unit is not provided. Figure 2 As shown, when three guide units 1a, 1b, and 1c are arranged in the flue 20, the two guide units 1a and 1c located on both sides are first guide units provided with two mixing elements 3, and the guide unit 1b located in the middle is the third guide unit not provided with a mixing element 3.

[0082] If the number of the guide units 1 is an even number and the number of the guide channels is an odd number, at this time, the number of the first guide units is one more than the number of the third guide units and they are arranged in sequence with intervals and staggered, and there is also a second guide unit located at the outermost or innermost side.

[0083] Of course, when the number of the guide units 1 is at least three, each guide unit 1 may be provided with a mixing piece 3, for example, the guide unit 1 located at the outermost or innermost side may be provided with two mixing pieces 3, and each of the remaining guide units 1 may be provided with one mixing piece 3. When some guide units 1 are provided with two mixing pieces 3 to form a first guide unit, and some guide units 1 are not provided with a mixing piece 3 to form a third guide unit, the overall structure can be simplified, which is convenient for mass production, and the force on the rear end of a single guide unit 1 can be balanced.

[0084] The angle between the first blade 31 and the guide plate 11 and the angle α between the second blade 32 and the guide plate 11 are preferably 120°-150°, that is, the angle α between the blade and the outer wall of the guide unit 1 is preferably 120°-150°. If the angle α is too large, such as 160° or 170°, the mixing effect is poor. If the angle α is too small, such as 90° or 100°, the resistance of the blade to the smoke is large. When the angle α formed by the blade and the straight segment 14 is set to 120°-150°, such as 120°, 130°, 140°, 150°, etc., the resistance caused by the blade to the smoke can be reduced while ensuring the mixing effect. In this embodiment, the angle α between each blade and the guide plate 11 can be equal or unequal, and no specific limitation is made here.

[0085] The spacing between two adjacent first blades 31 and the spacing between two adjacent second blades 32 are preferably 1.2D-1.6D, and the length B of the first blade 31 and the second blade 32 is preferably 0.8D-1.2D. If the length of the blade is too large, such as 1.5D, or the distance between two adjacent blades on the same side of the straight segment 14 is too small, such as 1.1D, the blade will have a greater resistance to the flow of flue gas, higher energy consumption, and higher system operating costs. If the length of the blade is too small, such as 0.5D, or the distance between two adjacent blades on the same side of the straight segment 14 is too large, such as 1.8D, the mixing effect may be unsatisfactory. The distance between two adjacent blades on the same side of the straight segment 14 is 1.2D-1.6D, such as 1.2D, 1.4D, 1.6D, and the length of the blade is 0.8D-1.2D, such as 0.8D, 1D, 1.2D. This can reduce the resistance to the flue gas while ensuring a more ideal mixing effect, thereby reducing the energy consumption of the flue gas flowing along the flue 20.

[0086] Each blade has an ammonia injection pipe 21 corresponding thereto on its front side. The projection of the axis of the ammonia injection pipe 21 corresponding to the first blade 31 on the surface of the first blade 31 coincides with the center line of the first blade 31. The projection of the axis of the ammonia injection pipe 21 corresponding to the second blade 32 on the second blade 32 coincides with the center line of the second blade 32. In this way, the injected reducing agent ammonia can form a vortex on the leeward side of the blade when flowing along the flue gas, thereby strengthening the mixing of the reducing agent ammonia and the flue gas, thereby further ensuring the mixing effect of the flue gas and the reducing agent ammonia.

[0087] like Figure 1 As shown, the guide member 30 has a similar structure to the guide member 30 in the prior art, and only includes a plurality of guide plates arranged in parallel, which are used to guide the smoke at the second turning portion.

[0088] In the denitrification system, the flue gas coming out of the economizer enters the first horizontal section 201 of the flue 20 from the inlet, passes through the first turning part through the diversion, ammonia injection, and mixing integrated device 10, and the flue gas is diverted by the diversion unit 1. The ammonia injection part injects reducing agent ammonia into the flue gas through the ammonia injection pipe 21, and then the flue gas and the reducing agent ammonia are mixed in the mixing part and enter the vertical section 202, and then flow toward the downstream side along the vertical section 202 and reach the rectifying grid 40 for rectification after being guided by the guide member 30, and finally reach the catalyst 50 to participate in the reaction of denitrification.

[0089] That is to say, after the flue gas passes through the integrated diversion, ammonia spraying and mixing device 10, it can achieve the effects of ammonia spraying and mixing while achieving diversion, and then further mixing can be achieved in the flue 20 flowing between the integrated diversion, ammonia spraying and mixing device 10 and the catalyst 50, so that the flue gas and the reducing agent ammonia can be mixed earlier and the mixing distance can be longer when the overall length of the flue 20 remains unchanged, thereby ensuring the mixing effect of the flue gas and the reducing agent ammonia when they reach the catalyst 50, thereby ensuring the flue gas denitrification effect.

[0090] The following are the results of a simulation experiment on the denitrification system provided in this embodiment.

[0091] The three-dimensional structure of the denitrification system is as follows Figure 6 As shown, the cross-sections of the first horizontal section 201 and the vertical section 202 of the inlet flue 20 are both 10m×3m, and the size of each layer of catalyst 50 is 10m×10m×1m. The main design parameters are as follows: Flue gas volume 1620000m 3 / h, flue gas temperature 354℃, ammonia consumption 254kg / h, dilution air volume 7780m 3 / h, room temperature, the resistance of each layer of catalyst 50 is 200Pa.

[0092] The specific implementation is described as follows: Figure 2 and Figure 3 As shown, the radii R1, R2, and R3 of the three guide units are 1050 mm, 1575 mm, and 1850 mm, respectively. The lengths L1, L2, and L3 of the straight section 14 are 650 mm, 875 mm, and 1250 mm, respectively. The first turning portion of the flue 20 is divided into four guide channels t1, t2, t3, and t4. Along the airflow direction, the size D of each guide channel is equal, which is 693 mm. The ammonia injection pipe 21 has an inner diameter of 30 mm. m circular tube, two rows of ammonia spray pipes 21 with a total of 160, the spacing between the two rows of ammonia spray pipes 21 along the airflow direction is 300 mm, the length of the ammonia spray pipe 21 located on the upstream side is 400 mm, the length of the ammonia spray pipe 21 located on the downstream side is 150 mm, in the same row of ammonia spray pipes 21, the spacing between two adjacent ammonia spray pipes 21 is 500 mm, and the flow velocity of the ammonia spray pipe 21 is 20 m / s; a mixing portion is provided at the rear end of the straight section of the guide units 1a and 1c.

[0093] The guide unit 1b is not provided with blades. The number of blades in the mixing section is 40 in total, which are in an isosceles trapezoidal shape. The upper and lower base lengths are 300 mm and 500 mm respectively, and the height is 700 mm (that is, the length of the blade is 700 mm), which is 1.01D; the spacing between two adjacent blades in the same row is 1000 mm, which is 1.443D; the angle α between the plane where the blade is located and the guide plate 11 is 135°, and the rear end of the straight segment 14 of the guide unit 1 forms a 90° sharp angle.

[0094] The schematic diagram of the mixed distance is as follows Figure 7 As shown, the numerical simulation test results of the specific embodiment are as follows Figure 8-12 As shown in Figure 2, the flue gas velocity distribution in the denitrification system is as follows: Figure 8 As shown, it can be seen that the color uniformity in the figure is good, the flue gas flow rate in the flue 20 is uniform, and the flow path of the reducing agent ammonia in the denitrification system is as follows Fig. 9 As shown, it can be seen that the color uniformity in the figure is good, the distribution uniformity of the reducing agent ammonia in the flue 20 is good, and the flue gas velocity distribution in the cross section of the flue 20 on the upstream side of the first layer catalyst 50 in the denitrification system is as follows Fig.10 As shown, it can be seen that the color uniformity in the figure is good, the flue gas velocity distribution is uniform in the cross section of the flue duct 20 on the upstream side of the catalyst 50, and the NH3 / NOx molar ratio distribution in the cross section of the flue duct 20 on the upstream side of the first layer of catalyst 50 in the denitrification system is as follows Fig.11 As shown, it can be seen that the NH3 / NOx molar ratio is in the range of 0.95-1.04. Therefore, the NH3 / NOx molar ratio distribution in the cross section of the flue 20 close to the first layer catalyst 50 is relatively uniform.

[0095] The Cv value (relative standard deviation) of the NH3 / NOx molar ratio distribution changes with the mixing distance as shown in Fig.12 As shown, the mixing distance refers to the distance from the mixing section along the flue gas flow direction. It can be seen that the Cv value of the NH3 / NOx molar ratio distribution uniformity at a mixing distance of 1.3m is 15.38%, and the Cv value of the NH3 / NOx molar ratio distribution uniformity at a mixing distance of 6.7m is 2.92% (less than 3%). When it reaches 0.5m upstream of the first layer catalyst 50, the Cv value of the NH3 / NOx molar ratio distribution uniformity is 1.75%, which is much better than the technical requirement of 5%, and can effectively ensure the long-term stable and efficient operation of the denitrification device. According to statistics, the resistance generated by the mixing section is 48Pa, which can ensure the stable operation of the system without excessive energy consumption.

[0096] In the description of the present application, it should be understood that the terms "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0097] In addition, the terms "first", "second", and "third" 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. Thus, a feature defined as "first", "second", and "third" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0098] The above are only preferred implementations of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A device for integrated flow diversion, ammonia injection and mixing, characterized in that: It comprises an ammonia spraying section, a mixing section and at least one flow guiding unit (1), wherein two sides of the flow guiding unit (1) respectively form flow guiding channels; The flow guide unit (1) comprises a mounting cavity (12), and the ammonia spraying part is mounted in the mounting cavity (12); The mixing section is arranged at the rear end of the guide unit (1); the side wall of the installation cavity (12) is also provided with an ammonia spraying member (2) communicating between the ammonia spraying section and the guide channel; the mixing section comprises mixing members (3) corresponding to each of the guide channels one by one; the mixing members (3) are fixedly arranged at the rear end of the guide unit (1).

2. The integrated device for guiding, spraying ammonia and mixing according to claim 1 is characterized in that: The ammonia spraying member (2) comprises a plurality of ammonia spraying pipes (21) arranged at intervals along the width direction of the flow guide unit (1), and each of the ammonia spraying pipes (21) is respectively connected to the ammonia spraying portion; The guide unit (1) has at least two ammonia spraying components (2) arranged at intervals along the length direction, and the ammonia spraying pipes (21) of different ammonia spraying components (2) have different lengths.

3. The integrated device for guiding, spraying ammonia and mixing according to claim 1 or 2, characterized in that: The guide unit (1) comprises an arc segment (13) and a straight segment (14) along the length direction; the straight segment (14) is arranged at the rear end of the arc segment (13); the radius of the arc segment (13) located on the outside is greater than the radius of the arc segment (13) located on the inside, and the length of the straight segment (14) located on the outside is greater than the length of the straight segment (14) located on the inside.

4. The integrated device for guiding, spraying ammonia and mixing according to claim 3 is characterized in that: The ammonia spraying portion is arranged in the straight line segment (14); And / or, the rear ends of the straight line segments (14) are all sharp-angle structures; And / or, the thickness of the front end of the arc segment (13) is smaller than the thickness of the rear end of the arc segment (13).

5. The integrated device for guiding, spraying ammonia and mixing according to claim 1 or 2, characterized in that: The mixing element (3) comprises a plurality of blades arranged at intervals along the width direction of the flow guide unit (1), the rear ends of the blades being arranged tilted toward one side of the flow guide channel, and the tilt directions of the blades of two adjacent mixing elements (3) are opposite.

6. The integrated device for guiding, spraying ammonia and mixing according to claim 5 is characterized in that: The blades of two adjacent mixing elements (3) are arranged in a staggered manner in sequence along the width direction of the flow guide unit (1).

7. The integrated device for guiding, spraying ammonia and mixing according to claim 5 is characterized in that: At least one of the flow guide units (1) comprises a first flow guide unit, wherein the first flow guide unit is fixedly provided with two mixing elements (3).

8. The integrated device for guiding, injecting ammonia and mixing according to claim 7 is characterized in that: When there are multiple flow guiding units (1), the multiple flow guiding units (1) include a second flow guiding unit and / or a third flow guiding unit; The second flow guiding unit is provided with a mixing element (3) which is located at the outermost side or the innermost side; The third flow guiding unit is not connected to the mixing element (3), and the third flow guiding unit and the first flow guiding unit are arranged in a staggered manner.

9. The integrated device for guiding, spraying ammonia and mixing according to claim 7, characterized in that: The ammonia injection pipe (21) is correspondingly arranged on the front side of the blade, and the projection of the axis of the ammonia injection pipe (21) corresponding to the blade on the blade coincides with the center line of the blade.

10. A denitration system, characterized in that: It comprises a flue (20), and the integrated device for guiding, spraying ammonia and mixing as claimed in any one of claims 1 to 9; The flue (20) comprises a bend, and the integrated flow guiding, ammonia spraying and mixing device is arranged in the bend.

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