CN212701335U - SCR denitration device for coal-fired boiler - Google Patents
SCR denitration device for coal-fired boiler Download PDFInfo
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- CN212701335U CN212701335U CN202020598811.7U CN202020598811U CN212701335U CN 212701335 U CN212701335 U CN 212701335U CN 202020598811 U CN202020598811 U CN 202020598811U CN 212701335 U CN212701335 U CN 212701335U
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Abstract
The utility model discloses a SCR denitrification facility for coal fired boiler, SCR denitrification facility includes: the denitration flue, the ammonia injection grid, the flue gas heat exchanger, the dilution fan, the ammonia gas-air mixer and the controller, wherein the ammonia injection grid is arranged in the denitration flue; the smoke heat exchanger is arranged in the denitration smokeIn the flue, the flue gas heat exchanger is provided with a heat exchange inlet and a heat exchange outlet; the dilution fan is provided with a fan inlet and a fan outlet, the fan outlet is communicated to the heat exchange inlet, and the air quantity of the dilution fan is adjustable; the ammonia gas air mixer is provided with an air inlet, an ammonia gas inlet and an exhaust port, the air inlet is communicated with the heat exchange outlet, the ammonia gas inlet is connected with the ammonia gas preparation device, and the exhaust port is connected with the ammonia spraying grid; the controller adjusts the air quantity of the dilution fan according to the load of the coal-fired boiler. According to the utility model discloses a NO that is used for coal fired boiler's SCR denitrification facility, can fully desorption boiler coal-fired back productionxAnd (3) harmful gases.
Description
Technical Field
The utility model belongs to the technical field of SCR method denitration technique and specifically relates to a SCR denitrification facility for coal fired boiler is related to.
Background
In the related art, it is pointed out that more and more coal-fired boilers use Selective Catalytic Reaction (SCR) to remove NO produced during boiler combustionxUsually NH is used3As a reducing agent for catalytic reaction, in the temperature range of 300-400 ℃, the flue gas passes through the SCR reactor and is sprayed with the reducing agent NH3Reaction takes place to produce H2O and N2Thereby realizing NO of coal-fired boilerxEmission control is favorable to reducing the emission of pollutant, alleviates atmospheric haze phenomenon and takes place.
NH injected into SCR reaction3Mainly comes from three ways: urea, liquid ammonia and ammonia water, all of which produce NH by corresponding devices3And (4) spraying the gas into an ammonia spraying grid at the inlet of the SCR reactor. Along with the improvement of safety control requirement and public safety consciousness, there is great potential safety hazard in liquid ammonia and aqueous ammonia in transportation and use, in case leaked, will cause poisoning, pollution and explosion accident, consequently, more and more power plants change SCR denitration reductant into urea, are favorable to promoting the security of reductant in transportation, storage and use.
In the preparation of NH3In the gas process, urea needs to be decomposed into NH3、H2O and CO2Mixed gas, in order to ensure that the decomposed mixed gas does not generate condensation and NH3The re-dissolution problem of (2) requires that the temperature of the hydrolyzate is not lower than 140 ℃ and that NH is ensured3Does not explode before entering the flue and requires dilution air to react with NH3Diluting and mixing to obtain NH in the mixed gas3The concentration is controlled within the lower explosion limit, therefore, in order to prevent the temperature of the product after urea hydrolysis from being reduced, the dilution air needs to be heated to ensure that the temperature is not lower than 140 ℃, thereby ensuring the normal operation of the whole dilution mixing system and the ammonia injection grid system.
The SCR denitration device in the related art adopts a flue gas heat exchanger technology to heat a dilution air system, but the technology is difficult to monitor and adjust the mixing ratio of dilution air and ammonia gas in real time, cannot adjust the temperature of the dilution air, and has adverse effects on subsequent ammonia injection control and flow distribution.
SUMMERY OF THE UTILITY MODEL
The utility model discloses aim at solving one of the technical problem that exists among the prior art at least. Therefore, the utility model provides a SCR denitrification facility for coal fired boiler, the NO that SCR denitrification facility can fully desorption boiler coal-fired productionxHarmful gases and substances.
According to the utility model discloses a SCR denitrification facility for coal fired boiler, include: a denitration flue; the ammonia injection grid is arranged in the denitration flue and used for injecting ammonia gas into the denitration flue; the flue gas heat exchanger is arranged in the denitration flue and is used for carrying out heat exchange with flue gas in the denitration flue, and the flue gas heat exchanger is provided with a heat exchange inlet and a heat exchange outlet; the dilution fan is provided with a fan inlet and a fan outlet, the fan outlet is communicated to the heat exchange inlet, and the air volume of the dilution fan is adjustable; the ammonia gas air mixer is provided with an air inlet, an ammonia gas inlet and an exhaust port, the air inlet is communicated with the heat exchange outlet, the ammonia gas inlet is connected with an ammonia gas preparation device, and the exhaust port is connected with the ammonia injection grid; and the controller adjusts the air volume of the dilution fan according to the load of the coal-fired boiler.
According to the utility model discloses a SCR denitrification facility for coal fired boiler comes the dilution amount of wind of adjusting dilution fan in real time through the load in the controller according to coal fired boiler, realizes adjusting the mixing proportion of dilution wind and ammonia in ammonia air mixer to ensure that the required ammonia of denitration can exist steadily before getting into the denitration flue, and then guarantee the normal operating of whole diluting device and ammonia injection grid system, make the NO that produces behind the coal-fired boilerxHarmful gas is the utility model discloses a SCR denitrification facility desorption fully well.
According to some embodiments of the utility model, the SCR denitrification facility still includes: and the air quantity regulating valve is connected with the dilution fan in series and used for regulating the air quantity of the dilution fan, and the controller regulates the opening of the air quantity regulating valve according to the load of the coal-fired boiler.
In some embodiments, the coal-fired boiler has one denitration flue, or the coal-fired boiler has two denitration flues arranged at intervals, the ammonia injection grid and the flue gas heat exchanger are arranged in each of the two denitration flues, and the two flue gas heat exchangers in the two denitration flues are connected in parallel.
Furthermore, the number of the dilution fans is one, and the heat exchange inlets of the two flue gas heat exchangers are communicated to the fan outlets of the dilution fans; or the two dilution fans correspond to the two flue gas heat exchangers one by one.
Still further, the ammonia air mixer includes two, and two ammonia air mixers correspond to two dilution fans one to one.
In some embodiments, the SCR denitration device further includes: and the flowmeter is connected between the heat exchange outlet and the air inlet in series.
In some embodiments, the SCR denitration device further includes: the dilution air bypass pipeline is connected to two ends of the flue gas heat exchanger in parallel, and a bypass regulating valve is connected to the dilution air bypass pipeline in series; the temperature detector is arranged between the heat exchange outlet and the air inlet and is positioned at the downstream of the dilution air bypass pipeline, the controller is respectively connected with the bypass adjusting valve and the temperature detector, and the controller adjusts the opening degree of the bypass adjusting valve according to the temperature value detected by the temperature detector.
According to some embodiments of the utility model, the ammonia injection grid with gas heater interval arrangement in flue gas flow direction is in the denitration flue, gas heater locates the upside or the downside of ammonia injection grid, gas heater includes a plurality of rectification heat exchange tubes, the setting of rectification heat exchange tube perpendicular to flue gas flow direction.
According to some embodiments of the utility model, flue gas heat exchanger includes first rectification heat exchanger and the second rectification heat exchanger that the interval set up on flue gas flow direction, first rectification heat exchanger includes a plurality of first rectification heat exchange tubes of parallel arrangement, first rectification heat exchange tube perpendicular to denitration flue width direction's setting, second rectification heat exchanger includes a plurality of parallel arrangement second rectification heat exchange tube, second rectification heat exchange tube perpendicular to denitration flue depth direction's setting, just first rectification heat exchange tube perpendicular to second rectification heat exchange tube.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
Drawings
Fig. 1 is a schematic view of an embodiment of an SCR denitration device according to the present invention;
FIG. 2 is a schematic view of another embodiment of an SCR denitration device according to the present disclosure;
FIG. 3 is a schematic view of yet another embodiment of an SCR denitration device according to the present disclosure;
FIG. 4 is a schematic view of yet another embodiment of an SCR denitration device according to the present disclosure;
FIG. 5 is a schematic view of an embodiment of a flue gas heat exchanger of the SCR denitration device shown in FIG. 1;
FIG. 6 is a schematic view of another embodiment of the flue gas heat exchanger shown in FIG. 5;
FIG. 7 is a schematic view of yet another embodiment of a flue gas heat exchanger of the SCR denitration device shown in FIG. 1;
FIG. 8 is a schematic view of yet another embodiment of the heat exchanger shown in FIG. 7 along its length;
fig. 9 is a graph of an embodiment of controlling the amount of wind of the dilution fan according to the SCR denitration device of the present invention;
fig. 10 is a graph of another embodiment of the SCR denitration device shown in fig. 9 for controlling the amount of wind of the dilution fan.
Reference numerals:
SCR denitration device 100:
a denitration flue 1, an ammonia injection grid 2,
a flue gas heat exchanger 3, a first rectifying heat exchanger 31, a second rectifying heat exchanger 32, a heat exchange inlet 301, a heat exchange outlet 302, a heat exchange pipe 303, a first rectifying heat exchange pipe 303a, a second rectifying heat exchange pipe 303b,
the dilution fan 4, the fan outlet 41,
an ammonia air mixer 5, an air inlet 51, an ammonia inlet 52, an exhaust port 53,
the device comprises an ammonia gas preparation device 6, an air volume adjusting valve 7, a flowmeter 8, a dilution air bypass pipeline 9, a bypass adjusting valve 91 and a temperature detector 10.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are exemplary and intended to be used for explaining the present invention, and should not be construed as limiting the present invention.
An SCR denitration device 100 for a coal-fired boiler according to the present invention is described below with reference to fig. 1 to 10.
As shown in fig. 1, according to the utility model discloses a SCR denitrification facility 100 for coal fired boiler, include: denitration flue 1, ammonia injection grid 2, flue gas heat exchanger 3, dilution fan 4, ammonia air blender 5 and controller (not shown in the figure).
Specifically, the ammonia injection grid 2 may be disposed in the denitration flue 1, and the ammonia injection grid 2 may be used to inject ammonia gas into the denitration flue 1; the flue gas heat exchanger 3 can be arranged in the denitration flue 1, the flue gas heat exchanger 3 is used for carrying out heat exchange with flue gas in the denitration flue 1, and the flue gas heat exchanger 3 is provided with a heat exchange inlet 301 and a heat exchange outlet 302; the dilution fan 4 is provided with a fan inlet and a fan outlet 41, the fan outlet 41 is communicated to the heat exchange inlet 301, and the air volume of the dilution fan 4 is adjustable.
The ammonia gas and air mixer 5 is provided with an air inlet 51, an ammonia gas inlet 52 and an exhaust port 53, wherein the air inlet 51 can be communicated with the heat exchange outlet 302, the ammonia gas inlet 52 can be connected with the ammonia gas preparation device 6, and the exhaust port 53 can be connected with the ammonia injection grid 2; the controller can adjust the air volume of the dilution fan 4 according to the load of the coal-fired boiler, for example, the controller can adjust the air volume by adjusting the rotating speed of the fan, or can adjust the air volume by controlling the opening and closing degree of the fan outlet 41.
According to the utility model discloses a SCR denitrification facility 100's theory of operation as follows: the dilution fan 4 drives an air flow out of the fan outlet 41 and the air flowThe size of the flue gas can be adjusted by a controller according to the load of the coal-fired boiler, the air flow enters the flue gas heat exchanger 3 through the heat exchange inlet 301 along the pipeline, the air flow flows in the flue gas heat exchanger 3 and exchanges heat with the flue gas in the denitration flue 1 so as to be heated, the heated air flow flows out of the heat exchange outlet 302 and enters the ammonia air mixer 5 through the air inlet 51 along the pipeline, meanwhile, ammonia gas prepared in the ammonia gas preparation device 6 enters the ammonia gas air mixer 5 from the ammonia gas inlet 52, heated air flow and ammonia gas are mixed in the ammonia gas air mixer 5 to form mixed air flow, the mixed air flow is discharged from the exhaust port 53 and flows into the ammonia spraying grid 2 in the denitration flue 1 along a pipeline, and finally, when the flue gas flows through the ammonia injection grid 2 in the denitration flue 1, the mixed gas flow of ammonia and air is injected from the ammonia injection grid 2, wherein the ammonia and NO in the flue gas.xAnd reacting to remove harmful substances in the flue gas. From this, according to the utility model discloses a SCR denitrification facility 100 can come real-time adjustment to dilute the amount of wind according to the load in the coal fired boiler to ensure that the required ammonia of denitration can exist stably before getting into denitration flue 1, and then guarantee the normal operating of whole diluting device and ammonia injection grid 2 systems, ensure the NO that produces behind the coal-fired boilerxHarmful gas is the utility model discloses a SCR denitrification facility 100 desorption fully well.
According to the utility model discloses a SCR denitrification facility 100 for coal fired boiler, come the dilution amount of wind of adjusting dilution fan 4 in real time through the load in the controller according to coal fired boiler, realize adjusting the mixing proportion of dilution wind and ammonia in ammonia air mixer 5, thereby ensure that the required ammonia of denitration can exist steadily before getting into denitration flue 1, and then guarantee the normal operating of whole diluting device and ammonia injection grid 2 system, make the NO that produces behind the coal-fired boilerxHarmful gas is the utility model discloses a SCR denitrification facility 100 desorption fully well.
According to some embodiments of the present invention, referring to fig. 9 and 10, the air volume y of the fan and the load x of the coal-fired boiler satisfy:
wherein, a<b; a is a first set air flow value, m3H; b is a second set air flow value, m3H; the load x of the coal-fired boiler is the actual evaporation capacity/rated evaporation capacity of the coal-fired boiler.
Specifically, as shown in fig. 9, the dilution air flow rate control curve has an abscissa of the coal-fired boiler load and an ordinate of the dilution air flow rate, and is divided into three segments, wherein the air flow rate of the dilution air fan is a constant value a when the coal-fired boiler load is less than 30%, the air flow rate of the dilution air fan is b when the coal-fired boiler load is 110%, and the air flow rate of the dilution air fan is a linear curve between a point (0.3, a) and a point (1.1, b) when the coal-fired boiler load is between 30% and 110%.
From this, according to the utility model discloses a SCR denitrification facility 100 can change the amount of wind that dilutes fan 4 in real time according to coal fired boiler's load change to change the concentration that is used for the ammonia of denitration, and then make the denitration more abundant, the denitration effect is better.
Alternatively, referring to fig. 10, the air volume of the blower may also be set to be a constant value all the time, and the air volume of the blower may be a second set air volume value b all the time.
According to some embodiments of the present invention, referring to fig. 1 to 4, the SCR denitration device 100 may further include: and an air volume adjusting valve 7. Specifically, air regulation valve 7 concatenates with dilution fan 4, and the controller can be according to coal fired boiler's load regulation air regulation valve 7's aperture, from this, according to the utility model discloses air regulation valve 7 can adjust dilution fan 4's the amount of wind.
In some embodiments, referring to fig. 1 to 4, the coal-fired boiler may have one denitration flue 1, or the coal-fired boiler may have two denitration flues 1, the two denitration flues 1 are arranged at intervals, an ammonia injection grid 2 and a flue gas heat exchanger 3 are arranged in each denitration flue 1, and the two flue gas heat exchangers 3 in the two denitration flues 1 are connected in parallel, so that the influence between the flue gas heat exchangers 3 can be reduced. Here, it should be noted that a general small-sized coal-fired boiler has one denitration flue, and a large-sized coal-fired boiler has two denitration flues.
Further, referring to fig. 1 and fig. 2, there may be one dilution fan 4, and the heat exchange inlets 301 of the two flue gas heat exchangers 3 are both communicated to the fan outlet 41 of the dilution fan 4; or referring to fig. 3 and 4, the dilution fan 4 may also include two dilution fans 4, and the two dilution fans 4 correspond to the two flue gas heat exchangers 3 one to one. That is to say, one or two dilution fans 4 may be provided, and when there is only one dilution fan 4, the air volume of the dilution fan 4 may be divided to each flue gas heat exchanger 3; when the dilution fan 4 has two, can set up a corresponding dilution fan 4 for every gas heater 3, like this, can ensure that dilution fan 4 provides sufficient amount of wind for two gas heater 3.
Further, referring to fig. 3 and 4, the ammonia air mixer 5 may include two ammonia air mixers 5, and the two ammonia air mixers 5 correspond to the two dilution fans 4 one by one, so that the air volume supplied from each dilution fan 4 to the corresponding ammonia air mixer 5 can be accurately and synchronously regulated, and the matching ratio of ammonia and air is ensured to be appropriate and accurate.
In some embodiments, referring to fig. 1 to 4, the SCR denitration device 100 may further include: a flow meter 8. Specifically, the flow meter 8 is connected in series between the heat exchange outlet 302 and the air inlet 51, so that the flow meter 8 can accurately meter and feed back the flow of the dilution air entering the ammonia air mixer 5, thereby providing a basis for regulating and controlling the mixing ratio of the dilution air and the ammonia.
In some embodiments, referring to fig. 1 to 3, the SCR denitration device 100 may further include: a dilution air bypass pipeline 9 and a temperature detector 10. Specifically, the dilution air bypass pipeline 9 is connected in parallel at two ends of the flue gas heat exchanger 3, and the dilution air bypass pipeline 9 is connected in series with a bypass regulating valve 91; the temperature detector 10 is arranged between the heat exchange outlet 302 and the air inlet 51, and the temperature detector 10 is positioned at the downstream of the dilution air bypass pipeline 9, wherein the controller is respectively connected with the bypass adjusting valve 91 and the temperature detector 10, and the controller adjusts the opening degree of the bypass adjusting valve 91 according to the temperature value detected by the temperature detector 10.
Thus, when the temperature detector 10 detects that the temperature of the air discharged from the flue gas heat exchanger 3 is within a reasonable temperature range, the controller can control the bypass regulating valve 91 to be closed, and at the moment, the air flowing into the ammonia air mixer 5 is all the air heated in the flue gas heat exchanger 3; when the temperature detector 10 detects that the temperature of the air discharged from the flue gas heat exchanger 3 is out of a reasonable temperature range, the controller may adjust the opening and degree of the bypass adjusting valve 91 according to the temperature value detected by the temperature detector 10, thus, the low temperature air flow can enter the pipeline between the heat exchange outlet 302 and the air inlet 51 through the dilution air bypass pipeline 9 to neutralize the high temperature air flow therein, meanwhile, the flowmeter 8 can accurately measure and feed back the flow of the low-temperature dilution air flowing in from the dilution air bypass pipeline 9, thereby feeding back the real-time mixing proportion of the dilution air and the ammonia gas to prevent the over-imbalance of the mixing proportion of the dilution air and the ammonia gas caused by the purpose of realizing the temperature reduction of the dilution air unilaterally, therefore, the temperature of the dilution air can be ensured to be in a proper range, and the mixing proportion of the dilution air and the ammonia gas can be ensured to be reasonable.
According to some embodiments of the utility model, refer to fig. 1 to 4, ammonia injection grid 2 and gas heater 3 interval arrangement are in denitration flue 1 on flue gas flow direction, gas heater 3 locates the upside or the downside of ammonia injection grid 2, that is to say, gas heater 3 can locate the downside of ammonia injection grid 2, also can locate the upside of ammonia injection grid 2, like this, both can make full use of the heat of flue gas carry out the heat exchange with the air among the gas heater 3, also can make ammonia injection grid 2 spun ammonia fully react with the flue gas and carry out the denitration.
Referring to fig. 5 and 6, the flue gas heat exchanger 3 may include a plurality of rectifying heat exchanging pipes 303, and the rectifying heat exchanging pipes 303 may be disposed perpendicular to the flow direction of the flue gas, so as to perform the functions of rectifying and mixing the flow of the flue gas, so as to make NH at the outlet of the ammonia injection grid 23Can better react with NO in the smokexMixing, also can make rectification heat exchange tube 303 fully contact with the flue gas, ensure that the dilution air in rectification heat exchange tube 303 fully exchanges heat with the flue gas.
Further, referring to fig. 5 and 6, the rectifying heat exchange tubes 303 of the flue gas heat exchanger 3 may be arranged in an in-line manner, and uniformly arranged along the cross section at the inlet of the denitration flue 1, with equal transverse or longitudinal pitches, for example: the mother tubes of the flue gas heat exchanger 3 may be arranged in the front-rear direction of the denitration flue 1 (for example, the front-rear direction shown in fig. 5), and the corresponding rectifying heat exchange tubes 303 are perpendicular to the width direction of the boiler (for example, the left-right direction shown in fig. 5); or the flue gas heat exchanger 3 mother pipe can also be arranged in the left-right direction of the denitration flue 1 (such as the left-right direction shown in fig. 6), and the corresponding rectifying heat exchange pipe 303 is parallel to the width direction of the boiler.
According to some embodiments of the utility model, refer to fig. 7 and 8, flue gas heat exchanger 3 can also include first rectification heat exchanger 31 and second rectification heat exchanger 32, first rectification heat exchanger 31 sets up with second rectification heat exchanger 32 interval in the direction that the flue gas flows, first rectification heat exchanger 31 includes a plurality of first rectification heat exchange tubes 303a of parallel arrangement, first rectification heat exchange tube 303a is perpendicular to 1 width direction's of denitration flue setting, second rectification heat exchanger 32 includes a plurality of second rectification heat exchange tubes 303b of parallel arrangement, second rectification heat exchange tube 303b is perpendicular to 1 depth direction's of denitration flue setting, and first rectification heat exchange tube 303a is perpendicular to second rectification heat exchange tube 303b, therefore, flue gas heat exchanger 3 can further be improved to the thermal utilization efficiency of flue gas, make the flue gas carry out abundant heat exchange with the dilution wind. For example, as shown in fig. 7 and 8, on a projection plane parallel to the first rectification heat exchanger 31 and the second rectification heat exchanger 32, a projection of the first rectification heat exchange tube 303a is perpendicular to a projection of the second rectification heat exchange tube 303b, and a projection of the plurality of first rectification heat exchange tubes 303a and a projection of the plurality of second rectification heat exchange tubes 303b may be formed in a grid shape, wherein the first rectification heat exchanger 31 may be located above the second rectification heat exchanger 32, and the second rectification heat exchanger 32 may be located above the first rectification heat exchanger 31.
The SCR denitration control method for a coal fired boiler according to the present invention is described below.
According to the utility model discloses a SCR denitration control method for coal fired boiler, include the amount of wind of adjusting dilution fan 4 according to coal fired boiler's load.
Further, referring to fig. 9 and 10, the air volume y of the fan and the load x of the coal-fired boiler satisfy:
wherein, a<b; a is a first set air flow value, m3H; b is a second set air flow value, m3H; the load x of the coal-fired boiler is the actual evaporation capacity/rated evaporation capacity of the coal-fired boiler. Specifically, as shown in fig. 9, the dilution air flow rate control curve has an abscissa representing the load of the coal-fired boiler, an ordinate representing the dilution air flow rate, and is divided into three segments, wherein the air flow rate of the dilution air fan is a constant value a when the load of the coal-fired boiler is less than 30%, the air flow rate of the dilution air fan is b when the load of the coal-fired boiler is 110% of the maximum load, and the air flow rate of the dilution air fan is a linear curve between the point (0.3, a) and the point (1.1, b) when the load of the coal-fired boiler is between 30% and 110%. From this, according to the utility model discloses a SCR denitrification facility 100 can change the amount of wind that dilutes fan 4 in real time according to coal fired boiler's load change to change the concentration that is used for the ammonia of denitration, and then make the denitration more abundant, the denitration effect is better.
Alternatively, referring to fig. 10, the air volume of the blower may also be set to be a constant value all the time, and the air volume of the blower may be a second set air volume value b all the time.
According to the utility model discloses a NO that is used for coal fired boiler's SCR denitration control method, can fully desorption boiler coal-fired productionxHarmful gas, and the efficiency and the effect of denitration are better.
In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", and the like, indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore, should not be construed as limiting the present invention.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically limited otherwise.
In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," and "fixed" are to be construed broadly and may, for example, be fixedly connected, detachably connected, or integrally formed; the connection can be mechanical connection, electrical connection or communication; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.
While embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.
Claims (9)
1. An SCR denitration device for a coal-fired boiler, comprising:
a denitration flue;
the ammonia injection grid is arranged in the denitration flue and used for injecting ammonia gas into the denitration flue;
the flue gas heat exchanger is arranged in the denitration flue and is used for carrying out heat exchange with flue gas in the denitration flue, and the flue gas heat exchanger is provided with a heat exchange inlet and a heat exchange outlet;
the dilution fan is provided with a fan inlet and a fan outlet, the fan outlet is communicated to the heat exchange inlet, and the air volume of the dilution fan is adjustable;
the ammonia gas air mixer is provided with an air inlet, an ammonia gas inlet and an exhaust port, the air inlet is communicated with the heat exchange outlet, the ammonia gas inlet is connected with an ammonia gas preparation device, and the exhaust port is connected with the ammonia injection grid;
and the controller adjusts the air volume of the dilution fan according to the load of the coal-fired boiler.
2. The SCR denitration device for a coal-fired boiler according to claim 1, further comprising:
and the air quantity regulating valve is connected with the dilution fan in series and used for regulating the air quantity of the dilution fan, and the controller regulates the opening of the air quantity regulating valve according to the load of the coal-fired boiler.
3. The SCR denitration device for a coal-fired boiler according to claim 1, wherein the coal-fired boiler has one denitration flue; or the coal-fired boiler is provided with two denitration flues which are arranged at intervals, the ammonia injection grid and the flue gas heat exchanger are arranged in the two denitration flues, and the two flue gas heat exchangers in the two denitration flues are connected in parallel.
4. The SCR denitration device for the coal-fired boiler according to claim 3, wherein the number of the dilution fan is one, and the heat exchange inlets of the two flue gas heat exchangers are communicated to the fan outlet of the dilution fan; or the two dilution fans correspond to the two flue gas heat exchangers one by one.
5. The SCR denitration device for a coal-fired boiler according to claim 4, wherein the ammonia air mixer comprises two ammonia air mixers, and the two ammonia air mixers correspond to the two dilution fans one by one.
6. The SCR denitration device for a coal-fired boiler according to any one of claims 1 to 5, further comprising: and the flowmeter is connected between the heat exchange outlet and the air inlet in series.
7. The SCR denitration device for a coal-fired boiler according to any one of claims 1 to 5, further comprising:
the dilution air bypass pipeline is connected to two ends of the flue gas heat exchanger in parallel, and a bypass regulating valve is connected to the dilution air bypass pipeline in series;
a temperature detector disposed between the heat exchange outlet and the air inlet, the temperature detector being located downstream of the dilution air bypass line,
the controller is respectively connected with the bypass adjusting valve and the temperature detector, and the controller adjusts the opening degree of the bypass adjusting valve according to the temperature value detected by the temperature detector.
8. The SCR denitration device for the coal-fired boiler according to any one of claims 1 to 5, wherein the ammonia injection grid and the flue gas heat exchanger are arranged in the denitration flue at intervals in a flue gas flow direction, the flue gas heat exchanger is arranged on the upper side or the lower side of the ammonia injection grid, and the flue gas heat exchanger comprises a plurality of rectifying heat exchange tubes which are arranged perpendicular to the flow direction of flue gas.
9. The SCR denitration device for a coal-fired boiler according to claim 1, wherein the flue gas heat exchanger comprises a first rectifying heat exchanger and a second rectifying heat exchanger which are arranged at intervals in a flue gas flow direction, the first rectifying heat exchanger comprises a plurality of first rectifying heat exchange tubes which are arranged in parallel, the first rectifying heat exchange tubes are arranged perpendicular to a width direction of the denitration flue, the second rectifying heat exchanger comprises a plurality of second rectifying heat exchange tubes which are arranged in parallel, the second rectifying heat exchange tubes are arranged perpendicular to a depth direction of the denitration flue, and the first rectifying heat exchange tubes are perpendicular to the second rectifying heat exchange tubes.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020598811.7U CN212701335U (en) | 2020-04-20 | 2020-04-20 | SCR denitration device for coal-fired boiler |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020598811.7U CN212701335U (en) | 2020-04-20 | 2020-04-20 | SCR denitration device for coal-fired boiler |
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