Technical field
[0001]The present invention relates to a denitration apparatus for a coal-fired boiler.
BACKGROUND
[0002]In coal-fired boiler, denitrification device using ammonia as a reducing agent is widely used. Since such coal burning boiler denitration apparatus, if there is a bias in the installation position of the ammonia injection nozzle or the like bending of the duct flow velocity distribution of the exhaust gas in the duct, which can interfere with high efficiency of NOx removal performance, it is desirable to uniformly spread the ammonia.
[0003]
　Therefore, as shown in FIG. 3, in order to ensure the diffusion distance of ammonia gas ejected from the ammonia injection nozzle 44, a method of designing long vertical upflow duct installation position after the ammonia injection nozzle 44 is employed there. Further, by providing the rectifying device 42 to the inlet of the catalytic reactor 140, it rectifies the exhaust gas downflow flowing into the catalyst layer 46, thereby achieving a high efficiency of the denitration performance.
[0004]
　On the other hand, Patent Document 1, the direction and angle of the ammonia injection nozzle is varied by the exhaust gas flow passage configuration, the ammonia ejected from ammonia injection nozzle method to uniformly distributed in the flue gas is disclosed.
CITATION
Patent Document
[0005]
Patent Document 1: Japanese Patent Publication No. 9-24246
Summary of the Invention
Problems that the Invention is to Solve
[0006]
　Denitration apparatus for a coal-fired boiler, it is desirable to uniformly spread the ammonia, as described with reference to FIG. 3, in order to ensure the diffusion distance of ammonia gas ejected from the ammonia injection nozzle, vertical rise It must be designed the flow duct long.
[0007]
　Also, when adding a denitration apparatus to the existing boiler, in order to install the ammonia injection nozzle, layout change of the existing duct is required, each time requires a design, design time and cost is generated.
[0008]
　On the other hand, as in Patent Document 1, when changing the structure of the ammonia injection nozzle itself, there is a possibility that problems such as complexity and assembling difficulties of structure results.
[0009]
　Ammonia view of the above circumstances, an aspect of the present invention, a uniform velocity distribution of the exhaust gas at the installation position of the ammonia injection nozzle, by passing the exhaust gas by the rectifier state, ejected without lengthening the duct and to provide a coal-fired boiler denitration apparatus to uniformly diffuse the gas.
Means for Solving the Problems
[0010]
　In order to solve the above problems, denitration apparatus for a coal burning boiler employs the following solutions.
　That is, coal boiler denitration apparatus according to one aspect of the present invention, the bending duct having a bend portion which is bent in a part of the channel the exhaust gas flows, is connected to the outlet of the bending duct, a plurality of parallel plate rectifier having, ammonia injection nozzle for injecting ammonia gas, and provided with a catalyst layer in the channel, coal boiler denitration apparatus comprises a catalytic reactor, a comprising the portion flow path cross-sectional area is substantially constant a is, the rectifying device and the ammonia injection nozzle, the flow path cross-sectional area of the catalytic reactor located upstream of the catalyst layer is disposed at the inlet of the portion substantially constant, the ammonia injection nozzle, It is installed so as to be continuous with the rectifying device at immediately downstream of the flow straightener.
[0011]
　Denitration apparatus for a coal burning boiler according to the present embodiment, the rectifier and the ammonia injection nozzle upstream of the catalyst layer, and is located at the entrance of the part flow path cross-sectional area of ​​the catalytic reactor is substantially constant. Further, ammonia injection nozzle is installed so as to be continuous with the rectifier at immediately downstream of the rectifier device. Thus, uneven flow of the exhaust gas generated in the connected curved duct upstream of the catalytic reactor is rectified by the installed rectifier to ammonia injection nozzle upstream. Further, the rectifier device and the ammonia injection nozzle is installed in succession, no other components are placed in between. Therefore, exhaust gas passing through the ammonia injection nozzle is in a state of being rectified. Thus, the ammonia gas injected from the ammonia injection nozzle is suppressed variation of the ammonia concentration due to uneven flow can be diffused stably ammonia gas. In conventional denitrator which has been provided with the ammonia injection nozzle bend duct of occurrence of drift had to ensure diffusion distance of the ammonia gas in the duct. However, according to the denitration apparatus for a coal burning boiler according to the present embodiment, by integrally providing a rectifier device and the ammonia injection nozzle catalytic reactor, it is possible to shorten the duct which has been conventionally extended. Therefore, it is possible to reduce the size of the denitrification apparatus. Also, when adding a denitration apparatus to the existing boiler, in each case requires without layout change of the existing duct, it is possible to also design time reduction and cost savings.
[0012]
　Furthermore, the flow resistance of the ammonia injection nozzle itself can rectify the more exhaust gas. Therefore, the exhaust gas because it reaches the catalyst layer at a rectified state, it is possible to prevent ash deposition on the increase and the catalyst layer of the denitration performance.
[0013]
　In addition, when Kin設 the ammonia injection nozzle into the rectifier, it is possible to share the supporting structure, it is possible to reduce the cost of such a reduction in the number of parts. In addition, since the distance to the catalyst layer can be secured, it is possible to ensure the diffusion distance of the ammonia gas.
[0014]
　Moreover, since ammonia injection catalytic reactor nozzle is installed (catalytic reactor inlet) is a flow path cross-sectional area than bending duct is a region a flow rate of about 3 times greater exhaust gas is about 1/3 of the low speed, to allow reduction of the reduction and the ammonia injection nozzle erosion of the pressure loss.
[0015]
　Coal boiler denitration apparatus according to one aspect of the present invention, the bending duct having a bend portion which is bent in a part of the channel the exhaust gas flows, is connected to the outlet of the bending duct, ammonia ejecting ammonia gas the injection nozzle, and provided with a catalyst layer in the flow path, a denitrification device for a coal-fired boiler comprising a catalytic reactor, a comprising the portion flow path cross-sectional area is substantially constant, the ammonia injection nozzle, the the flow path cross-sectional area of ​​the catalytic reactor located upstream of the catalyst layer is disposed at the inlet of the portion substantially constant.
[0016]
　Denitration apparatus for a coal burning boiler according to the present embodiment, ammonia injection nozzle upstream of the catalyst layer, and the flow path cross-sectional area of ​​the catalytic reactor is installed at an entrance of the portion substantially constant. Drift of the exhaust gas generated in the connected curved duct upstream of the catalytic reactor is rectified by the flow resistance of the ammonia injection nozzle itself. Thus, ammonia gas ejected from the ammonia injection nozzle is suppressed variation of the ammonia concentration due to drift, upon which can be distributed stably ammonia gas, the exhaust gas reaches the catalyst layer in a state of being rectified. In conventional denitrator which has been provided with the ammonia injection nozzle bend duct of occurrence of drift had to ensure diffusion distance of the ammonia gas in the duct. However, according to the denitration apparatus for a coal burning boiler according to the present embodiment, by providing the ammonia injection nozzle to the catalytic reactor, it is possible to shorten the duct which has been conventionally extended. Therefore, it is possible to reduce the size of the denitrification apparatus. Also, when adding a denitration apparatus to the existing boiler, in each case requires without layout change of the existing duct, it is possible to also design time reduction and cost savings.
[0017]
　Further, catalytic reactor ammonia injection nozzle is installed (catalytic reactor inlet), since the flow path cross-sectional area than the bending duct is a region a flow rate of about 3 times greater exhaust gas is about 1/3 of the low speed, the pressure to allow reduction of the reduction and the ammonia injection nozzle erosion loss.
[0018]
　Furthermore, since not provided a rectifying device in the catalytic reactor, it is possible to reduce the simplification and manufacturing cost of the structure.
The invention's effect
[0019]
　According to the denitration apparatus for a coal burning boiler according to the present invention, a uniform velocity distribution of the exhaust gas at the installation position of the ammonia injection nozzle, by passing in a rectified state, the ammonia gas injected without lengthening the duct it can be uniformly diffused.
　Also, even when adding the denitration unit to the existing boiler, to allow additional denitration apparatus without changing the layout existing duct.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020]
FIG. 1 is a longitudinal sectional view of a coal-fired boiler denitration apparatus according to the first embodiment of the present invention.
FIG. 2 is a longitudinal sectional view of a coal-fired boiler denitration apparatus according to the second embodiment of the present invention.
It is a longitudinal sectional view of FIG. 3 conventional coal burning boiler denitration apparatus.
DESCRIPTION OF THE INVENTION
[0021]
　Hereinafter, the denitration apparatus for a coal burning boiler according to an embodiment of the present invention will be described with reference to the drawings.
[0022]
First Embodiment
　exhaust gas from a coal fired boiler passes through the coal-fired in the boiler denitration apparatus 1A, after being mixed with ammonia gas, by passing the catalyst layer 46, by a chemical reaction, nitrogen in the exhaust gas oxides (NOx) are decomposed into nitrogen and water vapor there is no environmental impact. Then, the exhaust gas nitrogen oxide (NOx) has been removed is discharged from the flue gas duct (not shown) to the atmosphere.
[0023]
　Figure 1 is a longitudinal sectional view of a coal-fired boiler denitration apparatus 1A according to a first embodiment of the present invention is shown. Coal boiler denitration apparatus 1A, for example, selective catalytic reduction denitrator (SCR: Selective Catalytic Reduction) and are. Coal boiler denitration apparatus 1A and a bending duct 20 and the catalytic reactor 40A. Duct outlet 22 of the bending duct 20, by being connected to the catalytic reactor 40A, bending duct 20 and the catalytic reactor 40A are integrated.
[0024]
　Curved duct 20 has a bend portion 24 which is bent a part of the flow path. Bending duct 20, the duct outlet 22 on the opposite side opening (inlet duct) is connected to the coal fired boiler (not shown). Exhaust gas containing nitrogen oxides discharged from a coal-fired boiler (NOx) is, flows toward the duct outlet 22 and flows from the duct inlet. When the exhaust gas passes through the bend 24, drift occurs in the flow of the exhaust gas by bending of the flow path.
[0025]
　From the duct inlet, the exhaust gas reaching the duct outlet 22 to the flow path direction and the horizontal direction, it flows toward the downstream of the catalytic reactor 40A.
[0026]
　Exhaust gas that has flowed from the duct outlet 22 to the catalytic reactor 40A, first, while passing through the section (enlarged flow path portion 48) the flow path of the catalytic reactor 40A is expanded, vertically to its flow direction from the horizontal direction It is turned to. Further, since the flow area is expanded to about three times, the flow rate of the exhaust gas is reduced to about 1/3.
[0027]
　Catalytic reactor 40A immediately downstream of the enlarged flow path portion 48 has a section channel cross-sectional area is substantially constant. The catalytic reactor 40A of the section the flow path cross-sectional area is substantially constant (in the drawing upper) upstream in this order from the rectifying device 42, the ammonia injection nozzle 44 and the catalyst layer 46 is provided. Rectifier 42 and the ammonia injection nozzle 44 is installed on the inlet side of the section flow path cross-sectional area is substantially constant (the upstream side), the ammonia injection nozzle 44 includes a rectifier 42 at immediately downstream of the flow straightener 42 It is installed as continuous. The flow path cross-sectional area is about three times the duct area. Superficial velocity is, in the duct, at 9m / s ~ 18m / s, preferably, is a 12m / s ~ 15m / s.
[0028]
　Rectifier 42 includes a plurality of parallel plate with the vertical direction lateral direction, a direction perpendicular to the plane longitudinally, and. A plurality of parallel plate is disposed at a predetermined interval in the horizontal direction. Fluid (exhaust gas) passing between parallel plates is flows becomes uniform by the flow path resistance of the parallel plate. In other words, it is rectified. Rectifier was parallel plate, but not limited thereto, but may be guide vanes or lattice.
[0029]
　Ammonia injection nozzle 44 is provided in plural, each disposed at predetermined intervals in the horizontal direction, and a circular tube that the direction perpendicular to the plane to the longitudinal direction, the nozzles extending downwardly from its respective circular tube a. Ammonia gas guided in a circular pipe by an unillustrated device is ejected into the exhaust gas through a nozzle extending downward. Ammonia gas, while being mixed with the exhaust gas in the flow path of the catalytic reactor 40A, towards the catalyst layer 46 which is installed downstream of the ammonia injection nozzle 44. Longitudinal rectifier longitudinal ammonia injection nozzle circular tube of equidistant preferably, in 2 to FIG. 1, but it was parallel both may be crossed.
[0030]
　The catalyst layer 46 is, for example, a ceramic or titanium oxide is assumed that carries, by passing the exhaust gas mixed with ammonia gas, a chemical reaction, nitrogen oxides in the exhaust gas (NOx) no environmental impact nitrogen Ya It decomposes to water vapor. The superficial velocity of at this time, in 3m / s ~ 6m / s, preferably, is a 4m / s ~ 5m / s.
[0031]
　According to the present embodiment, the following effects.
　Drift of the exhaust gas generated in the upstream-connected curved duct 20 of the catalytic reactor 40A is rectified by the rectifier 42 installed in the upstream ammonia injection nozzle 44. Further, the rectifier 42 and the ammonia injection nozzle 44 is installed in succession, no other components are placed in between. Therefore, exhaust gas passing through the ammonia injection nozzle 44 is in a state of being rectified. Thus, the ammonia gas injected from the ammonia injection nozzle 44 is suppressed variation of the ammonia concentration due to uneven flow can be diffused stably ammonia gas. In conventional denitrator which has been provided with the ammonia injection nozzle 44 is bent duct 20 caused the drift, it had to ensure the diffusion distance of the ammonia gas in the duct, denitrification coal burning boiler according to the present embodiment According to the apparatus 1A, by integrally providing a rectifier 42 and an ammonia injection nozzle 44 into the catalytic reactor 40A, it is possible to shorten the duct which has been conventionally extended. Therefore, it is possible to reduce the size of the denitrification apparatus. Also, when adding a denitration apparatus to the existing boiler, in each case requires without layout change of the existing duct, it is possible to also design time reduction and cost savings.
[0032]
　Furthermore, the flow resistance of the ammonia injection nozzle 44 itself can rectify the more exhaust gas. Therefore, the exhaust gas because it reaches the catalyst layer 46 in a state of being more rectified, it is possible to prevent ash deposition on the increase and the catalyst layer 46 of the denitration performance.
[0033]
　In addition, when Kin設 the ammonia injection nozzle 44 to the rectifier 42, it is possible to share the supporting structure, it is possible to reduce the cost of such a reduction in the number of parts. In addition, since the distance to the catalyst layer 46 can be secured, it is possible to ensure the diffusion distance of the ammonia gas.
[0034]
　Further, a catalytic reactor 40A that ammonia injection nozzle 44 is installed (catalytic reactor 40A inlet), since the flow rate in the flow path cross-sectional area larger exhaust gas than bending duct 20 is a region to be a low speed, reducing the pressure loss possible to reduce the erosion of and ammonia injection nozzle 44.
[0035]
Second Embodiment
　Next, a description will be given coal boiler denitration apparatus according to the second embodiment of the present invention. This embodiment differs from the first embodiment, unlike in the presence or absence of the rectifier device 42, is the same for the other points. Therefore, the difference from the first embodiment only describes, others omitted by using the same reference numerals.
[0036]
　Figure 2 is longitudinal sectional view of a coal-fired boiler denitration apparatus 1B according to the second embodiment of the invention are shown. Coal boiler denitration apparatus 1B according to this embodiment has the same configuration as that omitted rectifier 42 from coal burning boiler denitration apparatus 1A of the first embodiment. That is, the inlet side of the flow path cross-sectional area of ​​the catalytic reactor 40B is substantially constant interval (the upstream side), only the ammonia injection nozzle 44 is installed as a member for rectifying the flow of the exhaust gas.
[0037]
　According to the present embodiment, the following effects.
　Drift of the exhaust gas generated in the upstream-connected curved duct 20 of the catalytic reactor 40B is rectified by the flow resistance of the ammonia injection nozzle 44 itself. Thus, the ammonia gas injected from the ammonia injection nozzle 44 is suppressed variation of the ammonia concentration due to drift, upon which can be distributed stably ammonia gas, the exhaust gas reaches the catalyst layer 46 while being rectified to. In conventional denitrator which has been provided with the ammonia injection nozzle 44 into bend duct of occurrence of drift is had to ensure diffusion distance of the ammonia gas in the duct, coal boiler denitration apparatus according to the present embodiment According to 1B, by providing the ammonia injection nozzle 44 into the catalytic reactor 40B, it is possible to shorten the duct which has been conventionally extended. Therefore, it is possible to reduce the size of the denitrification apparatus. Also, when adding a denitration apparatus to the existing boiler, in each case requires without layout change of the existing duct, it is possible to also design time reduction and cost savings.
[0038]
　Further, a catalytic reactor 40B that ammonia injection nozzle 44 is installed (catalytic reactor 40B inlet), since the flow path cross-sectional area than the bending duct 20 is large flow rate of the exhaust gas is a region to be a low speed, Ya reduction in pressure loss allowing a reduction in the erosion of the ammonia injection nozzle 44.
[0039]
　Moreover, since the catalytic reactor 40B is not a rectifier 42 provided, it is possible to reduce the simplification and manufacturing cost of the structure.
DESCRIPTION OF SYMBOLS
[0040]
　1 (1A, 1B) coal boiler denitration device
　20 bending duct
　22 duct outlet
　24 bend
　40 (40A, 40B) catalytic reactor
　42 rectifier
　44 ammonia injection nozzle
　46 catalyst layer
　48 enlarged flow path portion

The scope of the claims

[Requested item 1]And bending duct having a bend portion which is bent in a part of the channel the exhaust gas flows,
　is connected to the outlet of the bending duct, rectifier, ammonia injection nozzle for injecting ammonia gas having a plurality of parallel flat plates, and a catalyst layer the provided in the flow path, the catalytic reactor, comprising a portion of the flow path sectional area is substantially constant
in a denitrification device for a coal burning boiler provided with,
　the rectifier device and the ammonia injection nozzle, the catalyst layer the flow path cross-sectional area of the catalytic reactor located in the upstream is arranged in the inlet of the portion substantially constant,
　the ammonia injection nozzle is disposed so as to be continuous with the rectifying device at immediately downstream of the rectifier device coal boiler denitration device being.
[Requested item 2]
　And bending duct having a bend portion which is bent in a part of the channel the exhaust gas flows,
　is connected to the outlet of the bending duct, provided the ammonia injection nozzle for injecting ammonia gas, and the catalyst layer in the flow path, the flow path a catalytic reactor, comprising a portion where sectional area is substantially constant
in a denitrification device for a coal burning boiler provided with,
　the ammonia injection nozzle, the catalytic reactor flow path cross-sectional located upstream of the catalyst layer area approximately constant with partial coal boiler denitration device disposed at the entrance of.