CN215654706U - Pulverized coal fired boiler denitration ammonia injection mixing device - Google Patents
Pulverized coal fired boiler denitration ammonia injection mixing device Download PDFInfo
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- CN215654706U CN215654706U CN202121336426.6U CN202121336426U CN215654706U CN 215654706 U CN215654706 U CN 215654706U CN 202121336426 U CN202121336426 U CN 202121336426U CN 215654706 U CN215654706 U CN 215654706U
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Abstract
The utility model discloses a denitration ammonia-injection mixing device of a pulverized coal boiler, which comprises a coal economizer outlet rear flue and an air preheater outlet front flue, wherein an ammonia-injection device is arranged in the coal economizer outlet rear flue, two layers of catalysts are sequentially arranged in the air preheater outlet front flue, a first flow guide device is arranged at the upstream of the ammonia-injection device, and a second flow guide device is arranged at the downstream of the ammonia-injection device; the first flow guide device comprises at least one group of flow guide plates and flow guide plate support rods, the flow guide plates are square in structure, a plurality of flow guide plates are obliquely arranged on the flow guide plate support rods at equal intervals, and the flow guide plate support rods are fixedly connected with the inner wall of the rear flue of the outlet of the economizer; the second guiding device comprises at least one group of spiral-flow plates and spiral-flow plate supporting rods, the structures of the spiral-flow plates are circular, the plurality of spiral-flow plates are equidistantly arranged on the spiral-flow plate supporting rods, and the spiral-flow plate supporting rods are fixedly connected with the inner wall of the flue after the coal economizer is exported. The utility model improves the flow uniformity of the flue gas, improves the ammonia gas distribution effect and improves the uniformity.
Description
Technical Field
The utility model relates to the field of flue gas denitration of pulverized coal boilers, in particular to a denitration ammonia-injection mixing device for a pulverized coal boiler.
Background
At present, the key of the design of an SCR denitration system is to realize the uniform mixing of a reducing agent and flue gas and the uniform distribution of a flow field. There are two important indicators of the performance of a denitration device: high removal efficiency and low ammonia escape rate. An important factor affecting these two performance indicators is the uniformity of the catalyst and the denitration flow field. The ammonia mixing technology adopted by different denitration engineering companies is different, the current mainstream ammonia mixing technology can be divided into two major categories, one is an ammonia spraying grid which is structurally characterized by small caliber and large number of nozzles, the uniform mixing of ammonia and flue gas is realized by using a large number of nozzles, and different manufacturers are different in nozzle arrangement, form and downstream turbulence devices; another type of standing vortex mixing device is a standing vortex mixing mechanism, such as a standing vortex mixer of FBE, a Deltawing mixer of BalckeDurr, and a star mixer of topiral.
The denitration catalyst is the core equipment of the SCR denitration device and is the basic condition for realizing high-efficiency removal. In order to realize higher removal efficiency, the method can start with the improvement of the volume of the catalyst and the enhancement of the activity of the catalyst, improve the treatment capacity of the catalyst on the flue gas and realize high removal rate of nitrogen oxides and high escape rate of ammonia. If the uniformity of the catalyst inlet is poor, the volume of the catalyst needs to be properly increased to make up for the deficiency of the flow field.
In catalyst design, an inlet flue gas flow field on the surface of a catalyst is required to meet certain uniformity, including speed, concentration deviation, incidence angle and the like. However, in practical engineering, the cross-sectional size of the denitration reactor is large, so that the distribution of the flow field at the catalyst inlet is difficult to meet the requirements, especially the mixing of NH 3/NOx. When the denitration device requires higher denitration efficiency, the phenomenon is more obvious, so that the denitration efficiency of the system is reduced, and the ammonia escape rate is increased. Therefore, it is a difficult problem to be solved by those skilled in the art that the denitration ability of the catalyst with a limited volume is fully exerted and the denitration efficiency is high under the condition of low ammonia escape.
SUMMERY OF THE UTILITY MODEL
The utility model aims to provide a denitration ammonia-spraying mixing device for a pulverized coal boiler, which solves the problems of low flue gas denitration efficiency and high ammonia escape rate.
In order to solve the technical problems, the utility model adopts the following technical scheme:
the utility model relates to a denitration ammonia-injection mixing device for a pulverized coal boiler, which comprises a coal economizer outlet rear flue and an air preheater outlet front flue, wherein an ammonia-injection device is arranged in the coal economizer outlet rear flue, and two layers of catalysts are sequentially arranged in the air preheater outlet front flue, and the denitration ammonia-injection mixing device is characterized in that: a first diversion device is arranged at the upstream of the ammonia injection device, and a second diversion device is arranged at the downstream of the ammonia injection device;
the first flow guide device comprises at least one group of flow guide plates and flow guide plate support rods, the flow guide plates are square in structure, a plurality of flow guide plates are obliquely arranged on the flow guide plate support rods at equal intervals, and the flow guide plate support rods are fixedly connected with the inner wall of the rear flue of the coal economizer outlet;
the second guiding device comprises at least one group of spiral-flow plates and spiral-flow plate supporting rods, the structures of the spiral-flow plates are circular and multiple, the spiral-flow plates are equidistantly arranged on the spiral-flow plate supporting rods, and the spiral-flow plate supporting rods are fixedly connected with the inner wall of the rear flue of the coal economizer outlet.
Furthermore, the thickness of the guide plate and the cyclone plate is 6-9 mm.
Furthermore, the first flow guide device is two groups arranged side by side, the flow guide plate support rods are arranged in parallel and are fixedly connected through a cross rod arranged vertically, and the flow guide plates are arranged in a cross mode.
Further, the second guiding device is two sets of that set up side by side, and is two sets of the mutual parallel arrangement of whirl board bracing piece is fixed through the horizontal pole connection of perpendicular setting, and is two sets of the mutual parallel arrangement of whirl board.
Furthermore, a guide plate reinforcing rib is welded on the guide plate.
Furthermore, both ends of the guide plate support rod and the swirl plate support rod are provided with an air vent.
Furthermore, flue wall reinforcing plates are welded between the guide plate supporting rods, the rotational flow plate supporting rods and the inner wall of the rear flue of the coal economizer outlet.
Furthermore, the windward sides of the guide plate support rod and the rotational flow plate support rod are additionally provided with anti-abrasion angle steel.
Compared with the prior art, the utility model has the beneficial technical effects that:
according to the utility model, by arranging the first flow guide device and the second flow guide device, the incoming flow of the flue gas can be adjusted, the disturbance of the flue gas is promoted, the uniformity of the flue gas is improved, and the incoming flow of the flue gas behind the first flow guide device is not influenced by the load of a unit.
The ammonia injection grid is optimized, the mixing of the reducing agent and the flue gas is realized through flue gas entrainment by utilizing the first flow guide device, the uniformity of ammonia gas distribution is ensured, and a better mixing effect is realized; in actual engineering, the reducing agent mixing effect can be realized by combining modes of partition arrangement, physical structure optimization and the like under the conditions of controlling smaller resistance and subsequent straight sections.
According to the utility model, the second flow guide device is arranged at the downstream of the ammonia spraying device, so that secondary mixing of ammonia gas and flue gas is promoted, the mixing effect is improved, the anti-interference performance on the incoming flow of the flue gas is improved, and the stable and reliable state of a denitration system under any load is ensured.
According to the utility model, the first flow guide device is arranged at the downstream of the ammonia spraying device, and the second flow guide device is arranged at the upstream of the ammonia spraying device, so that the flow uniformity of flue gas is improved, the ammonia gas distribution effect is improved, and the uniformity of flue gas is improved.
Drawings
The utility model is further illustrated in the following description with reference to the drawings.
FIG. 1 is a schematic structural diagram of a denitration ammonia-injection mixing device of a pulverized coal fired boiler according to the present invention;
FIG. 2 is a schematic flow diagram of flue gas of the denitration ammonia-injection mixing device of the pulverized coal fired boiler;
FIG. 3 is a front view of the denitration ammonia injection mixing device of the pulverized coal fired boiler of the present invention;
FIG. 4 is a side view of a denitration ammonia-injection mixing device of a pulverized coal fired boiler according to the present invention;
FIG. 5 is a schematic view of the installation of the baffle of the present invention;
FIG. 6 is a schematic view of the mounting of the support pole of the present invention;
FIG. 7 is an enlarged view taken at A in FIG. 6;
description of reference numerals: 1. a first flow guide device; 101. a baffle; 102. a guide plate support bar; 2. a second flow guide device; 201. a swirl plate; 202. a rotational flow plate support bar; 3. an ammonia injection device; 4. a rear flue at the outlet of the economizer; 5. an outlet front flue of the air preheater; 6. flue wall reinforcing plate.
Detailed Description
As shown in fig. 1-7, a denitration ammonia-injection mixing device for a pulverized coal boiler comprises a coal economizer outlet rear flue 4 and an air preheater outlet front flue 5, wherein an ammonia-injection device 3 is arranged in the coal economizer outlet rear flue 4, two layers of catalysts are sequentially arranged in the air preheater outlet front flue 5, a first flow guide device 1 is arranged at the downstream of the ammonia-injection device 3, and a second flow guide device 2 is arranged at the upstream of the ammonia-injection device 3; the setting up of first guiding device 1, second guiding device 2 can improve the mixing uniformity of ammonia and flue gas on the one hand, and on the other hand plays and carries out automatically regulated's effect to the flue gas incoming flow, improves and spouts the adaptability of ammonia mixing arrangement to becoming the operating mode, and the debugging operation is more simple and convenient, lays the basis for realizing full load denitration.
The first flow guide device 1 comprises at least one group of flow guide plates 101 and flow guide plate support rods 102, the flow guide plates 101 are square in structure, a plurality of flow guide plates 101 are obliquely arranged on the flow guide plate support rods 102 at equal intervals, and the flow guide plate support rods 102 are fixedly connected with the inner wall of the rear flue 4 at the outlet of the economizer; the first flow guide device 1 plays a role in forced rectification of incoming smoke, weakens the influence of uneven flow velocity of the front wall and the rear wall on ammonia spraying mixing, improves the mixing effect of a reducing agent and the smoke through a standing vortex effect, changes the outlet flow field reasonably, forms a relatively uniform smoke flowing state in a downstream flue, and is favorable for guaranteeing the heat exchange effect of the air preheater.
Second guiding device 2 includes at least a set of whirl board 201 and whirl board bracing piece 202, the structure of whirl board 201 is circular, a plurality of whirl boards 201 equidistant install on whirl board bracing piece 202, whirl board bracing piece 202 is fixed with economizer export back flue 4's inner wall connection, spout blowout ammonia of ammonia injection device 3 and air mixing's efflux mist, the efflux mist is peripheral diffusion behind the whirl board 201 that strikes second guiding device 2, fully mix with flue gas on every side.
In the implementation, under the BMCR 100% working condition, the nonuniformity of the velocity distribution is less than 15%, the flue gas incidence angles are all less than 10 degrees, and the nonuniformity of the ammonia concentration distribution is reduced to be less than 5%, so that the engineering requirement is met. The flow of the flue gas in the flue is smooth, and the direction of the airflow is rapidly changed into vertical downward after the airflow passes through the rectifying grids of the first flow guide device 1, the second flow guide device 2 and the ammonia spraying device 3 above the SCR reactor, so that the speed distribution is uniform, and the directionality is also consistent; in the mixed region of spouting ammonia, the flue gas produces obvious disturbance on a large scale when the ammonia injection grid front and back mixing plate of spouting ammonia device 3, is showing the mixed effect of reinforcing with the ammonia, has also realized the flue gas from mixing simultaneously, also plays the important role to improving the inhomogeneity of incoming flow self.
Specifically, refer to the guide plate 101, the whirl plate 201 thickness is 6-9 mm. The size of the guide plate support rod and the swirl plate support rod is
Specifically, referring to fig. 6 and 7, the first guiding device 1 is provided in two groups arranged side by side, two groups of guiding plate supporting rods 102 are arranged in parallel and are connected and fixed by a cross rod arranged vertically, and two groups of guiding plates 101 are arranged in a cross manner. The second guiding device 2 is two sets of that set up side by side, and two sets of whirl board bracing pieces 202 are parallel to each other and are connected fixedly through the horizontal pole of perpendicular setting, and two sets of whirl boards 201 are parallel to each other.
Specifically, a guide plate reinforcing rib is welded on the guide plate 101.
Specifically, both ends of the guide plate support rod 102 and the swirl plate support rod 202 are provided with vent holes, and the diameter of each vent hole is 6 cm.
Specifically, referring to fig. 7, flue wall reinforcing plates 6 are welded between the baffle support rod 102, the swirl plate support rod 202 and the inner wall of the economizer outlet rear flue 4.
Specifically, the windward sides of the guide plate support bar 102 and the swirl plate support bar 202 are additionally provided with anti-abrasion angle steel, and the type of the anti-abrasion angle steel is 75X 5.
The installation process of the utility model is as follows:
firstly, referring to the flowing direction of flue gas in FIG. 2, the number, the structure and the installation position of the flow guide devices are preset according to the embodiment, after a boiler is stopped, air replacement is carried out inside a flue, then, holes are formed in the inner wall plate of the flue 4 behind the outlet of an economizer, the flow guide devices are subjected to blanking, prefabrication, assembly and welding (the thickness of all the flow guide plates is 8mm) at 0 m according to a drawing, the flow guide devices are hung to the vertical flue of the flue 4 behind the outlet of the economizer at 32 m by a crane, the flow guide devices are conveyed to the inside of the vertical flue by manual chain reversing, and a cantilever type inner scaffold is erected inside the vertical flue. Because the upper part of the original ammonia spraying grid is provided with an ammonia spraying pipeline, the flow guide device is positioned according to a drawing and then is welded with the inner wall of the vertical flue.
All the contact positions of the guide plates 101 and the vertical flue wall plate are welded, and the height of the welding seam of all the welding positions is not less than the thickness of the thinnest part. The collision part of the guide plate 101 and the rotational flow plate 201 and the original rod piece or the newly added support rod in the flue is cut, the guide plate 101 and the rotational flow plate 201 are welded after avoiding the original rod piece or the newly added support rod, and the guide plate and the rotational flow plate are welded with the original rod piece or the newly added support rod; the newly-increased support rod meets the truss in the flue, and the newly-increased support rod is disconnected and connected with the truss profile steel. Each end of the support rod is provided with a phi 6 vent hole, and the windward side of the support rod needs to be additionally provided with an anti-abrasion angle steel with the model of 75X 5. The guide plate reinforcing ribs and the guide plate 101 are welded, and the height of a welding seam is not less than the thickness of the thinnest part. The steel is required to be subjected to rust removal before use, and ST2 grade of mechanical rust removal is carried out. And after the diversion device is installed, the vertical flue is recovered (including heat preservation).
The first flow guide device 1 and the second flow guide device 2 are newly added at the upstream and the downstream of the ammonia injection grid respectively, the mixing of ammonia gas and flue gas is enhanced through the forced turbulence effect, the mixing nonuniformity of the first layer of catalyst inlet section NH3/NOx in the reactor is reduced to below 5% from 26.4% before modification, the important effect is achieved on improving the denitration efficiency and reducing the ammonia escape, and the excessive ammonia injection condition can be effectively improved.
The non-uniformity of the velocity of the flue gas at the cross section of the inlet of the first layer of catalyst in the reactor is less than 15%, and the flue gas can quickly reach uniform velocity distribution after entering the reactor, thereby being beneficial to the full implementation of the denitration reaction.
By means of the rectification effect of the guide plate 101 and the rectification grating in front of the reactor, the movement direction of the flue gas is rapidly adjusted, the incident angle of the flue gas reaching the first layer of catalyst is less than 10 degrees, the flue gas is prevented from excessively scouring the catalyst, and the service life of the catalyst is ensured.
Newly-increased first guiding device 1 and second guiding device 2 possess the ability of adjusting flue gas inflow uniformity on a large scale, improve denitration system variable operating mode adaptability, and the resistance increases about 90Pa around the device is reformed transform, consequently combines the resistance that reforms transform back air preheater (air heater) to reduce by a wide margin, consequently the wholeness can promote.
The above embodiments are only for describing the preferred mode of the present invention, and do not limit the scope of the present invention, and various modifications and improvements of the technical solution of the present invention by those skilled in the art should fall within the protection scope defined by the claims of the present invention without departing from the spirit of the present invention.
Claims (8)
1. The utility model provides a pulverized coal fired boiler denitration spouts ammonia mixing arrangement, includes flue (4) behind the economizer export and flue (5) before the air preheater export, be provided with in flue (4) behind the economizer export and spout ammonia device (3), two-layer catalyst, its characterized in that have set gradually in flue (5) before the air preheater export: a first diversion device (1) is arranged at the upstream of the ammonia injection device (3), and a second diversion device (2) is arranged at the downstream of the ammonia injection device (3);
the first flow guide device (1) comprises at least one group of flow guide plates (101) and flow guide plate support rods (102), the flow guide plates (101) are square in structure, a plurality of flow guide plates (101) are obliquely arranged on the flow guide plate support rods (102) at equal intervals, and the flow guide plate support rods (102) are fixedly connected with the inner wall of the economizer outlet rear flue (4);
second guiding device (2) are including at least a set of whirl board (201) and whirl board bracing piece (202), the structure of whirl board (201) is circular, and is a plurality of equidistant the installing of whirl board (201) on whirl board bracing piece (202), whirl board bracing piece (202) with the inner wall connection of flue (4) is fixed behind the economizer export.
2. The denitration ammonia-injection mixing device for the pulverized coal fired boiler as set forth in claim 1, characterized in that: the thickness of the guide plate (101) and the thickness of the swirl plate (201) are 6-9 mm.
3. The denitration ammonia-injection mixing device for the pulverized coal fired boiler as set forth in claim 1, characterized in that: the first flow guide devices (1) are arranged in two groups side by side, the guide plate support rods (102) are arranged in parallel and are fixedly connected through a cross rod which is vertically arranged, and the guide plates (101) are arranged in a cross mode.
4. The denitration ammonia-injection mixing device for the pulverized coal fired boiler as set forth in claim 1, characterized in that: the second guiding device (2) is two sets of that set up side by side, and is two sets of whirl board bracing piece (202) parallel arrangement each other and through the horizontal pole connection of perpendicular setting fixed, two sets of whirl board (201) parallel arrangement each other.
5. The denitration ammonia-injection mixing device for the pulverized coal fired boiler as set forth in claim 1, characterized in that: and a guide plate reinforcing rib is welded on the guide plate (101).
6. The denitration ammonia-injection mixing device for the pulverized coal fired boiler as set forth in claim 1, characterized in that: both ends of the guide plate support rod (102) and the swirl plate support rod (202) are provided with a vent hole.
7. The pulverized coal fired boiler denitration ammonia injection mixing device of claim 6, characterized in that: flue wall reinforcing plates (6) are welded between the inner walls of the guide plate support rod (102), the swirl plate support rod (202) and the economizer outlet rear flue (4).
8. The pulverized coal fired boiler denitration ammonia injection mixing device of claim 6, characterized in that: and the windward sides of the guide plate support rod (102) and the swirl plate support rod (202) are additionally provided with anti-abrasion angle steel.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121336426.6U CN215654706U (en) | 2021-06-16 | 2021-06-16 | Pulverized coal fired boiler denitration ammonia injection mixing device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121336426.6U CN215654706U (en) | 2021-06-16 | 2021-06-16 | Pulverized coal fired boiler denitration ammonia injection mixing device |
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| CN215654706U true CN215654706U (en) | 2022-01-28 |
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| CN202121336426.6U Active CN215654706U (en) | 2021-06-16 | 2021-06-16 | Pulverized coal fired boiler denitration ammonia injection mixing device |
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Inventor after: Meng Dezhi Inventor after: Fu Jian Sheng Inventor after: Wang Rongjin Inventor after: Tan Hao Inventor after: Sun Jixuan Inventor after: Zhao Junying Inventor after: Yang Hongyu Inventor after: Wang Haofeng Inventor after: Wang Mingjun Inventor after: Wang Hongxia Inventor after: Sun Mingchang Inventor after: Wei Kai Inventor after: Yang Huilong Inventor after: Zhang Gaojie Inventor after: Wang Jinhai Inventor after: Gao Zhihang Inventor after: Zhang Fan Inventor after: Gao Wenmin Inventor after: Li Hongying Inventor after: Du Yaoming Inventor after: Li Honggang Inventor after: Geng Guoxin Inventor after: Xiao Guibin Inventor after: Wang Yuchuan Inventor after: Zhen Shibo Inventor before: Meng Dezhi Inventor before: Fu Jian Sheng Inventor before: Wang Rongjin Inventor before: Tan Hao Inventor before: Sun Jixuan Inventor before: Zhao Junying Inventor before: Yang Hongyu Inventor before: Wang Haofeng Inventor before: Wang Mingjun Inventor before: Wang Hongxia Inventor before: Sun Mingchang Inventor before: Wei Kai Inventor before: Yang Huilong Inventor before: Zhang Gaojie Inventor before: Wang Jinhai Inventor before: Gao Zhihang Inventor before: Zhang Fan Inventor before: Gao Wenmin Inventor before: Li Hongying Inventor before: Du Yaoming Inventor before: Li Honggang Inventor before: Geng Guoxin Inventor before: Xiao Guibin Inventor before: Wang Yuchuan Inventor before: Zhen Shibo |