JP2001187315A - Ammonia injecting device for denitration - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ammonia injecting device for denitration capable of obtaining high denitration efficiency and also capable of suppressing the leakage concentration of ammonia even in the case when the inlet concentration distribution of NOx in waste gas is changed. SOLUTION: In the ammonia injecting device 6 for denitration for injecting the ammonia to the waste gas at the inside of a waste gas duct 2 to which the waste gas is sucked in order to denitrate the nitrogen oxides contained in the waste gas discharged from a combustion equipment, the ammonia is injected in plural injection concentration distributions corresponding to plural inlet concentration distribution whom the nitrogen oxides contained in the waste gas enable to take to the waste gas in the waste gas duct 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ammonia injection device for denitrifying NOx in exhaust gas discharged from various types of combustion equipment, and more particularly to an ammonia injection device in which the inlet concentration distribution of NOx in the exhaust gas changes. The present invention relates to an ammonia injection device capable of maintaining a high denitration rate.

[0002]

2. Description of the Related Art Today, heat recovery steam boilers (HRSGs) for producing steam or hot water using heat of exhaust gas generated from various combustion facilities such as gas turbines and diesel engines.
r) is proposed and widely used. Here, the exhaust gas introduced into the boiler is discharged from the combustion equipment, nitrogen oxides: include (NOx NO or NO _2). This N
Since Ox is a causative substance of photochemical smog, it needs to be removed before being discharged to the outside of the boiler. In particular, depending on the region or country where the boiler is located, the allowable level of NOx in exhaust gas is strictly regulated by regulatory bodies, etc. It is necessary to introduce a boiler to remove NOx so as to be below this allowable level. Required as a prerequisite for

[0003] In order to effectively remove NOx in such exhaust gas, various NOx removal methods (denitration methods) have been proposed and put to practical use today. This denitration method is roughly classified into a dry method and a wet method. Among them, a selective catalytic reduction method (SCR method), which is a type of dry method, is most often used. In this selective catalytic reduction method, generally, ammonia (NH ₃ ) is used as a reducing agent, and titanium oxide (Ti) is used as a catalyst.
On an O ₂ ) -based catalyst carrier, vanadium (V), tungsten (W) or molybdenum (Mo) is used as an active ingredient.
(Eg, V ₂ O ₅₎ supporting a metal oxide such as
/ WO ₃ / TiO ₂ ) to decompose NOx into harmless nitrogen gas (N ₂ ) and water (H ₂ O).

A denitration reaction formula in the selective catalytic reduction method is represented by the following formula (1) for NO and by the following formula (2) for NO ₂ . 4NO + 4NH ₃ + O ₂ → 4N ₂ + 6H ₂ O (1) 6NO ₂ + 8NH ₃ → 7N ₂ + 12H ₂ O (2)

Here, most of the NOx in the exhaust gas is NO.
Therefore, the denitration reaction in the selective catalytic reduction method substantially follows equation (1). As shown in this equation (1), in the denitration reaction, NH ₃ reacts one-to-one with NOx in the exhaust gas. Therefore, N in the exhaust gas
In order to denitrify Ox ideally (no excess or shortage), the NH ₃ molar ratio (NH ₃ amount / NOx
It is necessary to determine the injection amount of NH ₃ so that the amount is constant.

[0006] In other words, the NOx concentration (inlet NOx concentration) in the inlet region to be implanted in NH _3, NH ₃ concentration (injecting NH ₃ concentration, inlet NH ₃ concentrations) injected such that is equal to each other , NH ₃ must be injected.
When this condition is violated, for example, when the injected NH ₃ concentration is lower than the inlet NOx concentration (when the injected amount of NH ₃ is small), the unreacted NOx flows out and the NOx concentration in the outlet region of the denitration region. (Outlet NOx concentration) increases, and the NOx denitration rate (inlet NOx concentration is α, outlet NOx
When the concentration is β, 100 × (1- (α−
defined by β) / α) is reduced, and the predetermined allowable level may not be able to be cleared.

On the other hand, injected NH ₃
When the concentration is high (when the injection amount of NH ₃ is excessive), the outlet NOx concentration decreases, but NH ₃ is contained in the exhaust gas.
₃ remains, and the remaining concentration of NH ₃ (outlet NH ₃ concentration, leak concentration) in the exit region of the denitration region is improved. However, since an allowable level is specified for the leak concentration of NH _{3 in} the exhaust gas, there is a problem in excessively injecting NH ₃ . Therefore,
As described above, it is clear that the injection NH ₃ concentration needs to be adapted to the inlet NOx concentration in the exhaust gas.

However, the distribution of the inlet NOx concentration is
Each part of the NH ₃ injection region is not always constant, and
For that varies with changes in flow velocity of the exhaust gas, the inlet NOx concentration and injected NH ₃ concentration injecting NH ₃ to be equal it was generally difficult.

Therefore, in order to solve such a problem,
NH according to inlet NOx concentration distribution _ThreeAdjust injection volume
A possible ammonia injection device has been proposed.
FIG. 12 shows such a conventional ammonia injector.
The overall configuration of the waste heat recovery heat exchange device used is shown from the side.
You. In FIG. 12, the exhaust heat recovery heat exchange device 100
Generally, exhaust gas for introducing exhaust gas from combustion equipment (not shown)
On the downstream side of the exhaust duct 101
And a chimney 102 provided.

Inside the exhaust gas duct 101, a duct burner 103, a high-temperature evaporator 104, and a nozzle 106 which is a part of an ammonia injection device 105 are arranged in order from the upstream side (combustion facility side) to the downstream side (chimney side). , Medium temperature evaporator 1
07, a denitration reactor 108, and two low-temperature evaporators 109 are provided. The exhaust gas drawn into the exhaust gas duct 101 is heated by a duct burner 103 as necessary, and heat-exchanges in a high-temperature evaporator 104, a medium-temperature evaporator 107, and a low-temperature evaporator 109, and then passes through a chimney 102. The heat is recovered outside the heat recovery heat exchanger 100.

[0011] Here, the ammonia injection apparatus 105, the ammonia water supply source 110 (NH ₃ water) heated to the generating ammonia vapor (NH ₃ vapor), a plurality of NH ₃ vapor supplied from the supply source 110 Branch line 1
12 and each branch line 11
2 is provided.
The nozzle 106 is connected to the exhaust gas duct 101 as described above.
And through this nozzle 106, NH ₃
Water vapor is injected (sprayed) into the exhaust gas. Then, NOx and NH ₃ water vapor in the exhaust gas reach the denitration reactor 108 and react as shown in the above formula (1), whereby NOx is decomposed.

The procedure for adjusting the injection amount of NH ₃ steam in the exhaust heat recovery heat exchange apparatus 100 configured as above will be described. First, NH ₃ water vapor is uniformly ejected from the nozzle 106, and the NOx concentration in the exhaust gas at this time is measured by a NOx measuring element (not shown) (a plurality of NOx measuring elements are provided between the denitration reactor 108 and the chimney 102). . Then, based on the measurement result, the injection amount of NH ₃ water vapor is increased by opening the damper 113 provided in the branch pipe line 112 at a location where the outlet NOx concentration is high, and the damper 113 is opened at a location where the outlet NOx concentration is low. NH by closing
₃ reduce the amount of injected steam.

The series of steps from the measurement step to the injection amount adjustment step are repeatedly performed until a desired denitration ratio is obtained, so that the injection amount of NH ₃ steam is adjusted to the optimum amount corresponding to the inlet NOx concentration. You can get closer. When the desired denitration ratio can be obtained, the injection amount of NH ₃ steam is fixed (damper 1).
13 is fixed), and thereafter, denitration is performed based on the fixed injection amount.

Here, when examining the fluctuation factors of the inlet NOx concentration distribution in the exhaust gas, one of the major effects is the switching of the combustion / non-combustion of the duct burner 103. That is, during combustion of the duct burner 103, the exhaust gas in the surrounding area is heated by the duct burner 103, and NOx in the surrounding area increases. On the other hand, when the duct burner 103 is not burning, the inlet NOx concentration is relatively uniform. As described above, the distribution of the NOx concentration at the inlet greatly differs depending on whether the duct burner 103 is in the combustion state or the non-combustion state.

The change in the inlet NOx concentration distribution according to the operating condition of the duct burner 103 is 70 to 80.
However, obtaining a low denitration rate of about 10% was not so significant. However, in a situation in which a high denitration rate of 85 to 90% or more is required in accordance with recent tightening of environmental regulations, a change in the inlet NOx concentration distribution due to such an operation state of the duct burner 103 causes the denitration rate to decrease. The effect is large. Therefore, it is necessary to adjust the NH ₃ injection concentration in accordance with the change in the inlet NOx concentration distribution. However, in the conventional ammonia injection device 105, as described above, only the damper 11 is used.
Since the injection amount was adjusted by the opening degree of No. ₃ , it was difficult to change the injection concentration (injection amount) of NH ₃ according to the change in the inlet NOx concentration due to the operation state of the duct burner 103.

If the total amount of NOx does not change even if the inlet NOx concentration distribution itself changes, N
It is sufficient to inject a total amount of NH ₃ corresponding to the total amount of Ox and mix them sufficiently before reaching the denitration reactor. Also in this case, as a result, the inlet NOx concentration distribution and the injected NH ₃
Since the concentration distribution can be adjusted, a high denitration rate can be obtained, and the leak concentration of NH ₃ can be suppressed.

However, the distance from the nozzle 106 to the denitration reactor 108 has a certain limitation due to the installation space and the like. Generally, this distance is not sufficient, so that sufficient mixing as described above must be performed. It is difficult.
Therefore, in order to obtain a high denitration rate and to suppress the NH ₃ leak concentration, as described above, the duct burner 1
It was necessary to change the injection NH ₃ concentration (injection amount) in accordance with the change in the inlet NOx concentration due to the operating condition of No. 03.

The present invention has been made in view of the above-mentioned problems in the conventional ammonia injection apparatus for denitration, and has a high denitration even when the concentration distribution of inlet NOx in exhaust gas changes. It is an object of the present invention to provide an ammonia injection device for denitration, which can obtain a rate and can suppress a leak concentration of ammonia.

[0019]

In order to achieve the above object, an ammonia injection apparatus for denitration according to claim 1 is provided to denitrify nitrogen oxides contained in exhaust gas discharged from a combustion facility. An ammonia injection device for denitration for injecting ammonia into an exhaust gas in a gas path into which the exhaust gas is drawn, wherein nitrogen oxide contained in the exhaust gas can be taken from the exhaust gas in the gas path. It is characterized in that ammonia can be injected with a plurality of injection concentration distributions corresponding to a plurality of inlet concentration distributions.

As described above, NOx contained in exhaust gas
Inlet concentration distribution depends on whether the duct burner is burning or not.
Changes regularly or irregularly depending on factors such as
Sometimes. In this case, only a fixed injection concentration
NH on cloth_ThreeInjection of NOx
NH for degree distribution_ThreeConcentration distribution does not correspond, NH _Three
Is insufficient to lower the denitration rate or NH_ThreeIs excessive
And the leak concentration is improved.

Therefore, as described above, a plurality of inlet NOx
NH ₃ can be injected at a plurality of injection concentration distributions corresponding to the concentration distribution, and NH ₃ is injected at the injection concentration distribution corresponding to the inlet NOx concentration distribution at each point in time during the denitration, so that the inlet NOx concentration distribution becomes The injection NH ₃ concentration distribution can be made to correspond to this. Therefore, it is possible to inject NH ₃ into NOx without excess and deficiency, to maintain a high denitration rate, and to suppress the leak concentration of NH ₃ to a low level.

Further, the ammonia injection apparatus for denitration according to claim 2 includes a plurality of ammonia injection systems for injecting ammonia with a plurality of mutually different injection concentration distributions, and selectively switches the plurality of ammonia injection systems. By switching to the above, ammonia can be injected at an injection concentration distribution corresponding to the nitrogen oxide inlet concentration distribution.

This configuration is a part of a plurality of configurations that can be adopted to enable NH ₃ to be injected in a plurality of injection concentration distributions corresponding to a plurality of inlet NOx concentration distributions. That is, instead of injecting NH ₃ through a single NH ₃ injection system, a plurality of NH ₃ injection systems are provided, and the amount of NH ₃ injected in each injection system is different from each other. Be composed. Each time the inlet NOx concentration distribution changes, an injection system capable of injecting NH ₃ with the injected NH ₃ concentration distribution most corresponding to the changed inlet NOx concentration distribution is selected. In such a configuration, another method of changing the NH ₃ concentration distribution, for example, the outlet NOx
The denitration rate can be more easily improved as compared with a method in which the injection amount of NH ₃ is changed using feedback control using the measurement result of the concentration distribution as a feedback amount.

According to a third aspect of the present invention, there is provided an ammonia injection apparatus for denitration, wherein the inlet concentration distributions of the nitrogen oxides are two different inlet concentration distributions, and the inlet concentration distributions correspond to the respective inlet concentration distributions. And two ammonia injection systems capable of injecting water.

Further, in the ammonia injection apparatus for denitration according to the fourth aspect, the two inlet concentration distributions of the nitrogen oxides may be the inlet concentration at the time of combustion of the heating means provided near the upstream end of the gas path. A distribution and an inlet concentration distribution when the heating means is not burning.

According to the ammonia injection apparatus according to the present invention, the number of inlet concentration distributions that can be taken by NOx may be arbitrarily plural. For example, when NOx can take ten different inlet concentration distributions, This can be coped with by providing 10 injection systems. However, the number of inlet concentration distributions caused by combustion or non-combustion of the heating means such as a duct burner is two in total: the inlet concentration distribution during combustion and the inlet concentration distribution during non-combustion. In other words, if the ammonia injection system is configured to be able to cope with such two inlet concentration distributions, a high denitration rate can be obtained both during combustion and non-combustion of the heating means such as a duct burner. Can also be
The NH ₃ leak concentration can be suppressed.

[0027] Further, the ammonia for denitration according to claim 5 is provided.
The ammonia injection system is characterized in that
Source and ammonia supplied from this source
Distribution path that branches into and supplies a number of branch pipes, and this distribution path
Ammonia supplied from each branch line of
Nozzle group consisting of multiple nozzles
And each branch pipe of the distribution path has the above-mentioned configuration.
Adjust the amount of ammonia injected from the nozzle
It is configured by providing an adjusting means. This configuration is
This shows the basic configuration of the near injection system.
NH supplied _ThreeIs led to the nozzle through the distribution path,
Is injected into the exhaust gas from the nozzle.

Further, in the ammonia injection apparatus for denitration according to claim 6, the ammonia injection system comprises one system of the supply source, two systems of the distribution lines branched and connected to the supply source, and And a nozzle group of one system provided in common to the distribution lines of the system, and the adjusting means of each branch pipe of one of the distribution lines is provided with two inlet concentration distributions of the nitrogen oxides. Ammonia can be set to be injected at an injection concentration distribution corresponding to one of the inlet concentration distributions, and the adjusting means of each branch pipe of the other distribution passage is provided with two inlet concentration distributions of the nitrogen oxide. Is configured so that ammonia can be injected at an injection concentration distribution corresponding to the other inlet concentration distribution.

In this configuration, only two distribution paths are provided, and these two distribution paths are switched according to the operating condition of the superheating means such as a duct burner to optimize the NH ₃ injection amount. . Among the embodiments described below,
Particularly, the configuration is related to the first embodiment. In this configuration, the NH ₃ injection amount can be optimized only by providing two distribution paths, so that the object can be achieved with a very simple configuration.

The ammonia injection apparatus for denitration according to a seventh aspect of the present invention is characterized in that one system of the supply source, two systems of the distribution lines branched and connected to the supply source, and each of the distribution lines are individually provided. The two nozzle groups are connected to each other, and the adjusting means of each branch pipe of one distribution path corresponds to one of the two inlet concentration distributions of the nitrogen oxide. The injection means can be set so as to inject ammonia with an injection concentration distribution, and the adjusting means of each branch pipe of the other distribution path is adjusted to the other inlet concentration distribution of the two inlet concentration distributions of the nitrogen oxide. It is configured to be configurable to inject ammonia with a corresponding injection concentration distribution.

In this configuration, the distribution path and the valve group are provided in two systems, and the distribution path is switched according to the operating condition of the superheating means such as a duct burner, thereby optimizing the NH ₃ injection amount. This is a configuration particularly related to the second embodiment among the embodiments described later. In this configuration,
Since there is no need to share the valve group, the degree of freedom regarding the arrangement of the valves is improved, and a supply shutoff means for shutting off the distribution path downstream of the distribution path can be omitted.

Further, the ammonia injection apparatus for denitration according to claim 8 comprises two systems of the supply source, two systems of the distribution passages individually connected to the supply sources, and an individual system for each distribution passage. The two nozzle groups connected to the two nozzle groups are connected to each other, and the adjusting means of each branch pipe of one of the distribution paths is configured to adjust one of the two inlet concentration distributions of the nitrogen oxide to the inlet concentration distribution. Ammonia can be set to be injected at the corresponding injection concentration distribution, and the adjusting means of each branch line of the other distribution line is provided with the other inlet concentration distribution of the two inlet concentration distributions of the nitrogen oxide. Is set so as to inject ammonia with an injection concentration distribution corresponding to the above.

In this configuration, the distribution path, the valve group, and the supply source are each provided in two systems, and the distribution path and the like are switched according to the operation state of the superheating means such as the duct burner, thereby optimizing the NH ₃ injection amount. It is intended. This is a configuration particularly related to the third embodiment among the embodiments described later. In this configuration, since there is no need to share the supply source, the switching cutoff means for switching the distribution path upstream of the distribution path can be omitted.

In addition, the ammonia injection apparatus for denitration according to the ninth aspect is characterized in that:
In order to selectively switch the ammonia injection system, a switching shutoff means for shutting off the supply of ammonia as necessary is provided. By operating the switch interrupting unit, by blocking the NH ₃ supply, from the source to each distribution path, it is possible to switch the plurality of the NH ₃ injection systems. This configuration is particularly effective in a configuration in which a supply source is shared by a plurality of distribution paths.

According to a tenth aspect of the present invention, the denitrification ammonia injection device shuts off the supply of ammonia to each branch pipe of each of the distribution paths at a position near the downstream end thereof as necessary. It is provided with a supply cutoff means. By operating the supply cut-off means, by blocking the NH ₃ supply downstream of each distribution channel, it is possible to prevent the NH ₃ vapor flows into the branch pipe of the distribution path of the non-used side . This configuration is particularly effective in a configuration in which the nozzle group is shared by a plurality of distribution paths.

Further, in the ammonia injection apparatus for denitration according to claim 11, the plurality of nozzles of one of the nozzle groups correspond to one of the two inlet concentration distributions of the nitrogen oxide. Arranged in a distribution suitable for injecting ammonia in the injection concentration distribution, the plurality of nozzles of the other nozzle group correspond to the other inlet concentration distribution of the two inlet concentration distributions of the nitrogen oxides It is arranged in a distribution suitable for injecting ammonia according to the injection concentration distribution.

As described above, especially when a plurality of nozzle groups are provided and are not shared, the degree of freedom of the arrangement position of each nozzle is improved. In such a case, for example, the entrance NO
The nozzle group x concentrations are used if non-uniform, each nozzle, the injection NH ₃ areas that need to increase the density relatively centrally located, is necessary to increase the injected NH ₃ concentration The injection concentration distribution of NH ₃ can be adjusted to some extent depending on the arrangement position of the nozzles, for example, by arranging the NH ₃ relatively sparsely in the non-existing region. In this case, without changing the amount of adjustment by the adjusting means of each branch line so much,
NH ₃ water vapor can be injected with a desired NH ₃ concentration distribution.

Further, the ammonia injection apparatus for denitration according to a twelfth aspect is provided with an interlocking control means for performing control for switching the distribution path in association with a combustion or non-combustion state in the heating means. It is configured. The switching operation of the distribution path can be manually performed according to the operating state of the heating means such as a gas burner, but by providing the above-described interlocking control means, the injection system can be switched according to the operating state of the duct burner. Can be automatically switched, and the switching operation is easy. The configuration using such interlock control means will be described as the fourth embodiment, but can be similarly applied to the configurations shown in the second and third embodiments.

Further, in the ammonia injection apparatus for denitration according to the thirteenth aspect, the ammonia injected into the exhaust gas is liquefied ammonia, gaseous ammonia, or gas using ammonia water. Thus, the ammonia injected by the injection device can take any form, such as a gas or a liquid. Here, the ammonia water use gas is a gas containing ammonia water, and is a concept including an ammonia water use gas recirculation type, an ammonia water use electric heater type, and the like. For example, by injecting ammonia as water vapor, diffusion of ammonia into exhaust gas is promoted, and a more uniform ammonia concentration distribution can be obtained.

Further, in the ammonia injection apparatus for denitration according to claim 14, the adjusting means is a damper for changing an opening / closing degree of an internal path of the branch pipe. By changing the degree of opening and closing of the internal path of the branch pipe by this damper, the amount of NH ₃ water vapor passing through this internal path can be adjusted.

[0041]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of an apparatus for injecting ammonia for denitration according to the present invention. In the following embodiment, an example is shown in which the present ammonia injection apparatus is applied to an exhaust heat recovery heat exchange apparatus for recovering and utilizing heat of exhaust gas generated from a gas turbine. However, the source of the exhaust gas may be any combustion equipment other than a gas turbine,
In addition to being incorporated in the exhaust heat recovery heat exchange device, the present invention can be applied to all facilities for removing NOx in exhaust gas. Further, the present invention is not limited to the following embodiments for other components and methods.

(Embodiment 1) FIG. 1 is a side view showing the overall configuration of an exhaust heat recovery heat exchange apparatus to which an ammonia injection apparatus for denitration according to Embodiment 1 is applied. The present embodiment generally relates to an ammonia injection apparatus that includes a plurality of distribution paths of an NH ₃ injection system and that can switch the plurality of distribution paths according to the inlet NOx concentration distribution.

In FIG. 1, the exhaust heat recovery heat exchange device 1
Comprises an exhaust gas duct (casing) 2 and a chimney 3 provided downstream of the exhaust gas duct 2. The exhaust gas duct 2 draws exhaust gas from a gas turbine (not shown) communicating with one end of the exhaust gas duct 2 and forms a region necessary for performing heat exchange and denitration on the exhaust gas. Formed. The chimney 3 raises the exhaust gas discharged from the exhaust gas duct 2 to a predetermined high place area and discharges the exhaust gas to the outside of the exhaust heat recovery heat exchange device 1.

Inside the exhaust gas duct 2, a nozzle group which is a part of the duct burner 4, the high-temperature evaporator 5, and the ammonia injection device 6 in order from the upstream side (combustion facility side) to the downstream side (chimney side) 30, a middle temperature evaporator 7, a denitration reactor 8, and two low temperature evaporators 9 are provided. this house,
The duct burner 4 is a heating unit for additionally cooking (reheating) the exhaust gas introduced into the exhaust gas duct 2. The duct burner 4 is operated to switch between combustion and non-combustion (ON or OFF) in accordance with the load on the combustion equipment. More specifically, when the load on the combustion equipment is high, the duct burner 4 is set to the combustion state. The exhaust gas is then cooked, and when the load is low, it is set to a non-combustion state. Such switching of the duct burner 4 is performed automatically in conjunction with the load of the combustion equipment or manually by the driver. In the present embodiment, as shown, three duct burners 4 are arranged side by side along the vertical direction of the exhaust gas duct 2.

The high-temperature evaporator 5, the medium-temperature evaporator 7, and the two low-temperature evaporators 9 are heat exchange means for exchanging heat with the exhaust gas, respectively, and extend from the outside to the inside of the exhaust gas duct 2. It is configured as a multi-row heat transfer tube (fin tube). Water is circulated through the heat transfer tubes of the high-temperature evaporator 5, the medium-temperature evaporator 7, and the low-temperature evaporator 9, and the water is heated by the exhaust gas to generate steam, which is used as a power source for a power generation turbine (not shown). Used.

The denitration reactor 8 is a part of a denitration device for denitration of NOx in exhaust gas in cooperation with the ammonia injection device 6, and is supplied with NOx in exhaust gas and injected by the ammonia injection device 6. NH ₃ (in this embodiment, NH ₃ water vapor as described later) is reacted according to the principle of the selective catalytic reduction method. The denitration reactor 8 generally has V, V, as an active component on a TiO ₂ -based catalyst carrier.
It is provided with a catalyst (for example, V ₂ O ₅ / WO ₃ / TiO ₂ ) supporting an oxide of a metal such as W or Mo.
The catalyst of the denitration reactor 8 may be formed in any shape that allows its surface to come into contact with the exhaust gas. However, generally, the catalyst is formed in a plate shape or a lattice shape along the traveling direction of the exhaust gas. Is done. The configuration of the exhaust heat recovery heat exchange device 1 is as follows.
It can be changed as appropriate without departing from the technical idea described in the claims.
Can be reduced or additional economizers can be added.

Next, the ammonia injection device 6 for injecting NH ₃ water vapor will be described. The ammonia injection unit 6, as shown in FIG. 1, NH ₃ as a source 10 for supplying the steam, the distribution channel 20A of the supplied NH ₃ vapor branch supplies two systems from the supply source 10,
20B (hereinafter, a plurality of components having the same structure are denoted by “A” for components belonging to one system and “B” for components belonging to the other system. And the two distribution paths 20A, 20A,
The nozzle group 30 is provided in common to the nozzle group 0B.

The supply source 10 includes an ammonia dilution fan 11, an electric heater 12, and an ammonia water evaporator 13. The ammonia dilution fan 11 is a blowing unit that blows air for ammonia dilution. The air blown by the ammonia dilution fan 11 is heated by the electric heater 12 and introduced into the ammonia water evaporator 13. Further, NH ₃ water is introduced into the ammonia water evaporator 13 through an ammonia water introduction passage 14, and the NH ₃ evaporated water is supplied to the ammonia water evaporator 13.
By touching the heated air inside of the NH ₃ NH ₃ evaporated water is produced by evaporation. However, such a configuration of the supply source 10 is merely an example, and at least NH ₃
Can be supplied as long as it can be injected into the exhaust gas.

FIG. 2 is an enlarged view of the distribution path and the nozzle group. As shown in FIG. 2, each distribution path 20 includes one header 21A, 21B,
A, a plurality of branch lines 22A, 22B connected to 21B
It is provided with. The headers 21A and 21B distribute NH ₃ water vapor introduced from the ammonia water evaporator 13 through the primary line 15 and the secondary lines 16A and 16B to the branch lines 22A and 22B. .
Each branch pipeline 22A, 22B connected to this header 21
Is for guiding NH ₃ water vapor to each nozzle 31 of the nozzle group 30. As shown, the orifices 23A and 23B and the damper 2 are provided in these branch conduits 22A and 22B, respectively.
4A and 24B are provided in series. Orifice 2
3A and 23B measure the flow rate of NH ₃ .

The dampers 24A and 24B are
This is adjusting means for adjusting the amount of NH ₃ water vapor injected from Step 1. Specifically, the dampers 24A, 24B
Is provided with a shielding plate 24a that opens and closes the internal paths of the branch pipes 22A and 22B.
By changing the opening area of the internal path determined by the rotation angle of (i.e., the degree of opening and closing of the dampers 24A and 24B), the amount of NH ₃ water vapor passing through the internal path is adjusted. A method of determining the degree of opening and closing of the dampers 24A and 24B will be described later. In addition, as this adjusting means, N
It is sufficient that the injection amount of H ₃ steam can be adjusted, and well-known means other than the dampers 24A and 24B, for example, a flow control valve or the like can be used.

Each nozzle 31 of the nozzle group 30 is for injecting (spraying) NH ₃ water vapor supplied through the branch pipes 22A and 22B into the exhaust gas, and is drawn into the exhaust gas duct 2. It is connected to the ends of the branch conduits 22A and 22B. FIG. 3 shows a perspective view of the nozzle group 30. As shown in FIG. 3, assuming that the gas traveling direction is the Z direction and two directions orthogonal to the Z direction are the X direction and the Y direction as shown, the branch conduits 22A and 22B
It is inserted in the exhaust gas duct 2 side by side in the direction along the direction. A plurality of nozzles 31 are formed on the side surfaces of the branch pipes 22A and 22B inserted as described above. These nozzles 31 are connected to each branch line 22.
A and 22B are alternately arranged at different angles (about 45 degrees) with respect to A and 22B.
H ₃ water vapor can be sprayed. In addition, as shown in FIG. 11, the branch pipe 22A is inserted into the exhaust gas duct 2 in a direction along the X direction, and the branch pipe 22B is
It may be inserted into the exhaust gas duct 2 in a direction along the direction.

With such a configuration, the nozzles 31 are two-dimensionally arranged inside the exhaust gas duct 2 along the XY plane, and NH _{3 is} uniformly distributed with respect to the exhaust gas passing through the exhaust gas duct 2. Water vapor can be sprayed. The arrangement, number, and shape of the branch pipes 22 and the nozzles 31 shown in the drawings are merely examples, and can be arbitrarily configured as long as at least ammonia evaporating water can be injected into the exhaust gas duct 2. . However, it is preferable that the nozzles 31 are uniformly distributed in the XY plane, and it is preferable that the nozzles 31 have a structure in which the ammonia evaporating water can be diffused.

Next, setting of the degree of opening and closing (distribution adjustment) of the dampers 24A and 24B and switching of the respective distribution paths 20A and 20B will be described. First, the distribution adjustment of the dampers 24A and 24B will be described. As shown in FIG. 2, the damper 24A of one distribution path 20A and the damper 24B of the other distribution path 20B are set to have different degrees of opening and closing. More specifically, each damper 24A of the distribution path 20A has an injection concentration distribution corresponding to one of the two inlet concentration distributions that NOx in exhaust gas can take,
The opening and closing degree is set so that NH ₃ water vapor can be injected from the nozzle 31. Also, each damper 24 of the distribution path 20B
B denotes an injection concentration distribution corresponding to the other one of the two inlet concentration distributions, and the nozzle 31
The opening degree is set so that H ₃ steam can be injected.

The two inlet concentration distributions of NOx may be inlet concentration distributions that change due to any cause. In the present embodiment, however, the inlet NOx concentration distribution during combustion of the duct burner 4 is described. (Inlet NOx concentration distribution A)
And the inlet NOx concentration distribution (inlet NOx concentration distribution B) when the duct burner 4 is not burning. FIG. 4 is a diagram showing the relationship between the state of the duct burner and each concentration distribution, etc.
Shows the time when the duct burner is burning, and (b) shows the time when the duct burner is not burning. As shown in FIG. 4 (a), when the duct burner 4 burns, the exhaust gas in the surrounding area is heated by the duct burner 4 and the NOx in the surrounding area increases. Is unevenly distributed in the XY plane.

In order to obtain an injection NH ₃ concentration distribution (injection NH ₃ concentration distribution A) corresponding to such a non-uniform inlet NOx concentration distribution, each damper 2 of the distribution path 20A is provided.
The opening / closing degree of 4A is determined. Further, as shown in FIG. 4B, when the duct burner 4 is not burning, the exhaust gas is not heated by the duct burner 4, so that the inlet NO
The x-density distribution B becomes relatively constant in the XY plane. Therefore, each damper 24B of the distribution path 20B is provided so that an injection NH ₃ concentration distribution (injection NH ₃ concentration distribution B) corresponding to such a uniform inlet NOx concentration distribution is obtained.
Is determined.

The distribution of the dampers 24A and 24B may be adjusted by any method including logical calculation. For example, the distribution may be adjusted by using a NOx measuring element for measuring the NOx concentration. Can be. That is, first, in a state where the duct burner 4 is burned,
NH ₃ water vapor is evenly ejected from the nozzle 31, and the outlet NOx concentration in the exhaust gas at this time is determined by a NOx (not shown).
Measure with a probe.

Then, based on this measurement result, the exit N
In places where the Ox concentration is high, the injection amount of NH ₃ water vapor is increased by opening the damper 24A, and conversely, the outlet NOx
At a place where the concentration is low, the injection amount of NH ₃ water vapor is reduced by closing the damper 24A. By repeating such a series of steps from the measurement step to the injection amount adjustment step until a desired denitration ratio can be obtained, the injection amount of NH ₃ water vapor is adjusted to the optimum amount corresponding to the inlet NOx concentration A. Approach. When the desired denitration rate (for example, 85 to 90% or more) can be obtained, the opening / closing degree of the damper 24A is fixed,
The degree of opening and closing of each damper 24A of the distribution path 20A can be set.

Next, the duct burner 4 is set to non-combustion,
With the NH ₃ steam injection system switched by means described later, the same distribution adjustment as described above can be performed, and the degree of opening and closing of each damper 24B of the other distribution path 20B can be set.

Next, switching of the distribution paths 20A and 20B will be described. As shown in FIG. 2, valves 25A and 25B are provided in the secondary pipelines 16A and 16B from the ammonia water evaporator 13 to each of the headers 21A and 21B. The valves 25A and 25B are connected to the secondary line 1
Switching interruption means for interrupting the supply of ammonia evaporating water by interrupting 6A and 16B. Also,
As shown in FIGS. 1 and 2, valves 26A and 26B are provided in the branch pipes 22A and 22B of the distribution paths 20A and 20B at positions near the downstream end. These valves 26A and 26B are supply shutoff means for interrupting the supply of ammonia as needed.

When it is desired to supply NH ₃ steam from one distribution passage 20A, one valve 25A is opened and the other valve 25B is closed, and at the same time, one valve 26A is opened. This can be done by closing the other valve 26B. To supply NH ₃ steam from the other distribution passage 20B, one valve 25A is closed and the other valve 25B is opened, and at the same time, one valve 26A is closed and the other valve 25A is closed. This can be done by opening 26B.

As described above, by switching the valves 25A and 25B, it is possible to switch the NH ₃ water vapor injection system upstream of the distribution paths 20A and 20B, and by switching the valves 26A and 26B, the distribution path is switched. It is possible to switch the NH ₃ steam injection system downstream of 20. From these facts, by performing the opening / closing operation of the valve in accordance with the combustion / non-combustion state of the duct burner 4, it is possible to inject NH ₃ steam with an injection concentration distribution corresponding to the inlet NOx concentration distribution.

Next, an example of a trial calculation result by the present applicant will be described. 5 and 6 show the results of trial calculation of the NOx concentration and the like. Case 1 in FIG. 5 is a trial calculation result before the distribution adjustment of the damper during the combustion of the duct burner, and case 2 in FIG. 5 is a trial calculation result after the distribution adjustment of the damper when the combustion of the duct burner is performed, and FIG. Case 3 is the result of a trial calculation before switching the distribution path when the duct burner is not burning,
Case 4 in FIG. 6 is a trial calculation result after switching of the distribution path when the duct burner is not burning. The XY plane in the duct is divided into eight distribution-adjustable areas.

First, in case 1 of FIG. 5 (during the combustion of the duct burner and before the distribution adjustment), the inlet NOx concentration is not uniform, and the maximum value = 72 ppm and the minimum value = 53 ppm.
It is. On the other hand, since the distribution was not adjusted yet, the injected NH ₃ concentration was constant, and the maximum value = minimum value = 62.875 ppm. As a result of the denitration reaction, the average value of the outlet NOx concentration = an average value = 3.67 ppm outlet NH ₃ concentrations, a minimum value of the NOx removal rate = 86.60
%Met. The average value of the outlet NH ₃ concentration (leak concentration) was 3.67 ppm.

Next, in case 2 (after distribution adjustment) of FIG. 5, although the inlet NOx concentration is not different from that of case 1, the distribution of the injected NH ₃ concentration was unevenly adjusted corresponding to the inlet NOx concentration. , Maximum = 72 ppm, minimum =
It became 53 ppm. Then, as a result of the denitration reaction, the outlet N
Average value of Ox concentration = average value of outlet NH ₃ concentration = 2.21
Since ppm and the minimum value of the denitration rate were 95.72%, it can be seen that the outlet NOx concentration was reduced and the denitration rate was improved as compared with Case 1. Average value of leak concentration =
Since it was 2.21 ppm, it can be seen that the leak concentration was lower than in case 1.

Here, assuming that the duct burner is not burned, the NOx concentration at the inlet becomes constant and the maximum value = minimum value = 62.875 ppm as shown as case 3 in FIG. On the other hand, since the distribution of the damper 24 is still adjusted according to the inlet NOx concentration distribution during the combustion of the duct burner, the injected NH ₃ concentration is non-uniform, and the maximum value = 72 ppm and the minimum value = 53 ppm. Met. Therefore, the inlet NOx concentration distribution and the injected NH ₃ concentration distribution do not correspond to each other, and as a result of the denitration reaction, the average value of the outlet NOx concentration = the average value of the outlet NH ₃ concentration = 3.62 ppm, and the lowest denitration rate Value = 83.72%. Accordingly, it can be seen that the denitration rate was lower than in case 2 described above. Average value of leak concentration =
Since it became 3.62 ppm, it can be seen that the leak concentration was improved as compared with Case 2.

When the distribution is adjusted according to the inlet NOx concentration distribution when the duct burner is not burning, as shown in case 4 in FIG.
However, since the injected NH ₃ concentration was relatively uniform in correspondence with the inlet NOx concentration, the maximum value was 64.
ppm, minimum value = 61 ppm. As a result of the denitration reaction, the average value of the outlet NOx concentration = the average value of the outlet NH ₃ concentration = 2.25 ppm, and the minimum value of the denitration rate = 94.90.
%, It can be seen that the outlet NOx concentration was lower than in case 3 and the denitration rate was improved. Further, the denitration rate of Case 4 was almost the same level as Case 2. Further, since the average value of the leak concentration was 2.25 ppm, the leak concentration was suppressed, and the level was almost the same as that of Case 2.

In the present embodiment, the state after the distribution adjustment of the case 2 and the case 4 can be switched immediately according to the combustion / non-combustion of the duct burner. Since a low state hardly occurs, a high level of denitration can be maintained, and the leak concentration can be suppressed to a low level.

(Embodiment 2) FIG. 7 is a side view showing the overall configuration of an exhaust heat recovery heat exchange apparatus to which an ammonia injection apparatus for denitration according to Embodiment 2 is applied. The configuration that is not particularly described is the same as that of the first embodiment, and the same configuration is denoted by the same reference numeral. The present embodiment generally relates to an ammonia injector having a plurality of nozzle groups in addition to a plurality of distribution paths.

In FIG. 7, the exhaust heat recovery heat exchange device 40
The ammonia injection device 41 incorporated in is provided with two systems of nozzle groups 30A and 30B. The one nozzle group 30A is connected to only one distribution path 20A, and the other nozzle group 30B is connected to only the other distribution path 20B. FIG. 8 is a perspective view of the nozzle groups 30A and 30B.

As shown in FIG. 8, the nozzle groups 30A,
Each of 30B is formed on the side surface of each of the branch conduits 22A and 22B drawn into the exhaust gas duct 2 as in the first embodiment. These nozzle groups 30A, 30B
Are two-dimensionally arranged along the above-mentioned XY plane, and are arranged at a slight distance from each other. This interval can be set arbitrarily.

In this configuration, as shown in FIG. 7, by switching the valves 25A and 25B, during the combustion of the duct burner 4, NH ₃ water vapor is supplied through one distribution passage 20A and one nozzle group 30A. When the duct burner 4 is not burning, NH ₃ steam can be injected through the other distribution passage 22B and the other nozzle group 30B. In such an injection system, unlike Embodiment 1, there is no path that joins the two distribution paths 20A and 20B to the one nozzle group 30, so that the shutoff means such as the valves 26A and 26B in FIG. Can be omitted.

The nozzles 31A and 31B of each of the nozzle groups 30A and 30B may be formed to have the same structure as shown in FIG.
They may be arranged simply at the same position (only the position in the Z direction is different) in the direction. However, each nozzle 31
A and 31B can be arranged at positions more suitable for obtaining a desired implanted NH ₃ concentration distribution. For example, the injection N at the time of non-combustion and combustion of the duct burner 4
When the H ₃ concentration distributions A and B are roughly grasped, the above-described uniform injection N is applied to the nozzle 31B of the nozzle group 30B used when the duct burner 4 is not burning.
It may be arranged uniformly along the XY plane so as to conform to the H ₃ concentration distribution B.

Also, when the duct burner 4 is used for combustion,
The nozzle 31A of the nozzle group 30A to be
Non-uniform injection NH_ThreeInject to conform to concentration distribution A
NH _ThreeRelatively concentrated in areas where higher concentrations are required
And injected NH_ThreeFor areas where high concentration is not required
May be arranged relatively sparsely. In this case, the nozzle
Injection NH depending on the arrangement of 31A and 31B_ThreeDensity distribution adjustment
Has already been performed, and the dampers 24A, 24A
Without changing the degree of opening and closing of B so much,
In NH_ThreeNH in concentration distributions A and B_ThreeInject steam
Can be.

(Embodiment 3) FIG. 9 is a side view showing an overall configuration of an exhaust heat recovery heat exchange apparatus to which an ammonia injection apparatus for denitration according to Embodiment 3 is applied. The configuration that is not particularly described is the same as that of the above-described first or second embodiment, and the same configuration is denoted by the same reference numeral.
The present embodiment generally relates to an ammonia injection apparatus provided with a plurality of supply sources in addition to a plurality of distribution paths and nozzle groups.

In FIG. 9, the exhaust heat recovery heat exchange device 50
The ammonia injection device 51 incorporated in the
It is configured to include supply sources 10A and 10B. One companion
The supply source 10A is connected to only one distribution path 20A.
NH_ThreeTo supply steam, and to supply the other source 10B.
Is connected only to the other distribution path 20B, and _Three
Supply steam. Then, the combustion of the duct burner 4 /
Switching valves 25A and 25B according to non-combustion
, The source 10A or the source 10B
From NH_ThreeBy supplying steam, the nozzle groups 30A, 30
NH from either one of B_ThreeWater vapor can be injected
Wear.

In this case, the valves 25A and 25B may be omitted, and the injection system may be switched using means for determining whether or not NH ₃ water vapor is supplied from the supply sources 10A and 10B. Such means include, for example, ammonia dilution fans 11A and 11B. That is, when the duct burner 4 is burning, only the ammonia dilution fan 11A of one supply source 10A is operated to inject NH ₃ steam from the nozzle group 30A, and when the duct burner 4 is not burning, the ammonia dilution fan 11A of the other supply source 10B is used. By operating only the fan 11B, the nozzle group 3
NH ₃ water vapor can also be injected from 0B.

In this case, however, the nozzle group 3 is switched from the ammonia dilution fans 11A and 11B as switching means.
Since the injection path lengths to 0A and 30B are long, there is a possibility that the time difference between the switching of the ammonia dilution fans 11A and 11B and the actual injection / stop in the nozzle groups 30A and 30B may become large. Note that

(Embodiment 4) FIG. 10 is a side view showing the entire configuration of an exhaust heat recovery heat exchange apparatus to which an ammonia injection apparatus for denitration according to Embodiment 4 is applied. The configuration that is not particularly described is the same as that of the first embodiment, and the same configuration is denoted by the same reference numeral. The present embodiment generally relates to an ammonia injection apparatus having an automatic control system for switching the injection system in conjunction with the operating state of the duct burner, in addition to having a plurality of nozzle groups in the system. Things.

In the ammonia injection device 61 incorporated in the exhaust heat recovery heat exchange device 60 shown in FIG.
Valves 25A and 25B of A and 20B are formed as electric valves, and open / close control units 27A and
The opening / closing state is controlled by 27B. Similarly, the valves 26A and 26B are also formed as electric valves, and the open / close state is controlled by open / close control units 28A and 28B provided in the vicinity thereof (note that the open / close control units 28A and 28B
8B is partially omitted in the drawing). On the other hand, a combustion state output device 62 that outputs a signal indicating combustion / non-combustion of the duct burner 4 is arranged near the duct burner 4. The combustion state output device 62 can be configured as a control device that controls the duct burner 4 or a detection device that detects combustion / non-combustion of the duct burner 4 by detecting a combustion temperature or the like of the duct burner 4.

The open / close control units 27A, 27
B, 28A, 28B and the combustion state output device 62 are electrically connected to the interlock control device 63. The interlocking control device 63 is interlocking control means for performing switching control by the valves 25A, 25B and the valves 25A, 25B in conjunction with the combustion or non-combustion state in the duct burner 4. Specifically, when a signal indicating that the duct burner 4 is in a combustion state is input from the combustion state output device 62, the interlocking control device 63 sets the one open / close control unit 27
A, and outputs a control signal for opening the valves 25A and 26A to the 28A, and the other open / close control unit 2
A control signal for closing valves 25B and 26B is output to 7B and 28B.

When a signal indicating that the duct burner 4 is in a non-combustion state is input from the combustion state output device 62, the interlocking control device 63 controls the one of the open / close control units 27A,
8A, a control signal for closing the valves 25A, 26A is output, and the other open / close control unit 27B,
A control signal for opening valves 25B and 26B is output to 28B.

As described above, each of the valves 25A, 25B, 26
A and 26B are opened or closed under the control of the opening and closing control units 27A, 27B, 28A and 28B based on a control signal from the interlocking control device 63, and the injection system is automatically switched. According to such a configuration, in the operation at the initial stage of introduction of the ammonia injection device 61, it is necessary to perform distribution adjustment while measuring the outlet NOx concentration as described above. The injection system is automatically switched according to the operation state of the burner 4.

[0083]

As described above, according to the ammonia injection apparatus for denitration according to the present invention (claim 1), a plurality of injection concentration distributions corresponding to a plurality of possible inlet concentration distributions of nitrogen oxide can be obtained. Since ammonia can be injected, NH ₃ is injected at an injection concentration distribution corresponding to the inlet NOx concentration distribution at each point in time during denitration, so that the injected NH ₃ concentration distribution corresponds to the inlet NOx concentration distribution. Thus, a high denitration rate can be maintained, and the leak concentration of NH ₃ can be suppressed to a low level.

According to the ammonia injection apparatus for denitration according to the present invention (claim 2), a plurality of ammonia injection systems for injecting ammonia with a plurality of mutually different injection concentration distributions are provided. By selectively switching the ammonia injection system, it is possible to inject ammonia with an injection concentration distribution corresponding to the nitrogen oxide inlet concentration distribution. Therefore, every time the inlet NOx concentration distribution changes, the changed inlet NOx concentration is changed. An injection system capable of injecting NH ₃ with the injection NH ₃ concentration distribution most corresponding to the concentration distribution is selected, and the denitration rate can be more easily improved.

Further, according to the ammonia injection apparatus for denitration according to the present invention (claim 3), the possible inlet concentration distributions of nitrogen oxides are two different inlet concentration distributions, which correspond to each inlet concentration distribution. It is provided with two ammonia injection systems capable of injecting ammonia with an injection concentration distribution.

Further, according to the ammonia injection apparatus for denitration according to the present invention (claim 4), the two inlet concentration distributions of nitrogen oxide are determined by the heating means provided near the upstream end of the gas path. These are the inlet concentration distribution during combustion and the inlet concentration distribution when the heating means is not burning. Therefore, if the ammonia injection system is configured to be able to cope with such two inlet concentration distributions, both during combustion and non-combustion of the heating means such as a duct burner,
A high denitration rate can be obtained, and the leak concentration of NH ₃ can be suppressed.

Further, according to the ammonia injection apparatus for denitration according to the present invention (claim 5), it is provided with an ammonia supply source, a distribution path, and a nozzle group, and each branch pipe of the distribution path is provided. The passage is provided with adjusting means for adjusting the injection amount of ammonia injected from the nozzle, and NH ₃ supplied from a supply source is guided to the nozzle through a distribution passage, and this nozzle is Is injected into the exhaust gas.

Further, according to the ammonia injection apparatus for denitration according to the present invention (claim 6), there is provided one supply source, two distribution paths, and one nozzle group. With only two distribution channels, NH
_{(3) Since the} injection amount can be optimized, the object can be achieved with a very simple configuration.

Further, according to the ammonia injection apparatus for denitration according to the present invention (claim 7), the system is provided with one system of the supply source, two systems of the distribution path, and two systems of the nozzle group. With this configuration, there is no need to share a valve group, so that the degree of freedom regarding the arrangement of the valves is improved, and a supply shutoff means for shutting off the distribution path downstream of the distribution path can be omitted.

Further, according to the ammonia injection apparatus for denitration according to the present invention (claim 8), there are provided the two supply sources, the two distribution paths, and the two nozzle groups. Since it is configured, it is not necessary to share the supply source, so that the switching cutoff means for switching the distribution path upstream of the distribution path can be omitted.

According to the ammonia injection apparatus for denitration according to the present invention (claim 9), the ammonia injection system is selectively switched between the supply source and each of the distribution paths. A switch shutoff means for shutting off the supply of ammonia is provided if necessary. By operating the switch shutoff means to shut off the NH ₃ supply from the supply source to each distribution path, a plurality of NH ₃ The injection system can be switched.

Further, according to the ammonia injection apparatus for denitration according to the present invention (claim 10), each branch pipe of each of the above-mentioned distribution paths is provided at a position near the downstream end thereof as required. Since the supply cut-off means for cutting off the supply of ammonia is provided, the supply cut-off means is operated to cut off the NH ₃ supply at the downstream side of each distribution path, so that the NH ₃ water vapor is supplied to the distribution path on the non-use side. It can be prevented from flowing into each branch pipeline.

Further, the ammonia for denitration according to the present invention is provided.
According to the injection device (claim 11), one of the nozzles
Multiple nozzles in a group can be
Distribution suitable for injecting ammonia in the input concentration distribution
And a plurality of nozzles of the other nozzle group
Injection concentration distribution corresponding to the inlet concentration distribution
Since it is arranged in a distribution suitable for injecting
Injection NH_ThreeAdjust the concentration distribution to some extent
The amount of adjustment by the adjusting means of each branch line
Without significantly changing the desired implant NH_ThreeDark
NH in degree distribution _ThreeWater vapor can be injected.

Further, according to the ammonia injection apparatus for denitration according to the present invention (claim 12), control for switching the distribution path is performed in conjunction with the combustion or non-combustion state of the heating means. Since the interlocking control means is provided, the injection system can be automatically switched according to the operation state of the duct burner, and the switching operation is easy.

Further, according to the ammonia injection apparatus for denitration according to the present invention (claim 13), the ammonia injected into the exhaust gas is liquefied ammonia, gaseous ammonia, or gas using ammonia water. Thus, the ammonia injected by the injection device can take any form, such as a gas or a liquid.

Further, according to the ammonia injection apparatus for denitration according to the present invention (claim 14), the adjusting means comprises:
Since this is a damper for changing the degree of opening and closing of the internal path of the branch pipe, the degree of opening and closing of the internal path of the branch pipe can be changed to adjust the amount of NH ₃ water vapor passing through the internal path. .

[Brief description of the drawings]

FIG. 1 is a side view showing an overall configuration of an exhaust heat recovery heat exchange device to which an ammonia injection device for denitration according to a first embodiment of the present invention is applied.

FIG. 2 is an enlarged view showing a distribution path and a nozzle group 30 shown in FIG.

FIG. 3 is a perspective view showing a nozzle group shown in FIG.

4A is a diagram showing a state of the duct burner when the duct burner is burning, and FIG. 4B is a diagram showing a relationship between each concentration distribution and the like when the duct burner is not burning.

FIG. 5 is a diagram showing trial calculation results of NOx concentration and the like.

FIG. 6 is a diagram showing trial calculation results of NOx concentration and the like.

FIG. 7 is a side view showing an overall configuration of an exhaust heat recovery heat exchange apparatus to which an ammonia injection device for denitration according to a second embodiment of the present invention is applied.

FIG. 8 is a perspective view showing the nozzle group shown in FIG.

FIG. 9 is a side view showing an overall configuration of an exhaust heat recovery heat exchange apparatus to which an ammonia injection device for denitration according to a third embodiment of the present invention is applied.

FIG. 10 is a side view showing an overall configuration of an exhaust heat recovery heat exchange apparatus to which an ammonia injection device for denitration according to a fourth embodiment of the present invention is applied.

FIG. 11 is a perspective view showing a branch conduit and a nozzle in another embodiment.

FIG. 12 is a side view showing the overall configuration of a waste heat recovery heat exchange device to which a conventional ammonia injection device is applied.

[Explanation of symbols]

 1, 40, 50, 60 Exhaust heat recovery heat exchange device 2 Exhaust gas duct 3 Chimney 4 Duct burner 5 High temperature evaporator 6, 41, 51, 61 Ammonia injection device 7 Medium temperature evaporator 8 Denitration reactor 9 Low temperature evaporator 10 Supply source DESCRIPTION OF SYMBOLS 11 Ammonia dilution fan 12 Electric heater 13 Ammonia water evaporator 14 Ammonia water introduction path 15 Primary line 16 Secondary line 20 Distribution line 21 Header 22 Branch line 23 Orifice 24 Damper 25, 26 Valve 27, 28 Opening / closing control part 30 Nozzle group 31 Nozzle 62 Combustion state output device 63 Interlock control device

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toshio Koyanagi 1-1, Akunouramachi, Nagasaki City F-term in Nagasaki Shipyard, Mitsubishi Heavy Industries, Ltd. 4D002 AA12 AC01 AC10 BA06 BA12 BA13 CA01 DA07 DA11 DA21 DA70 EA02 GA02 GA03 GB01 GB02 GB06 GB08 HA08

Claims (14)

[Claims] 1. A denitration ammonia injection device for injecting ammonia into an exhaust gas in a gas path through which the exhaust gas is drawn in order to denitrate nitrogen oxides contained in the exhaust gas discharged from the combustion equipment. The denitration characterized in that ammonia can be injected into the exhaust gas in the gas path with a plurality of injection concentration distributions corresponding to a plurality of possible inlet concentration distributions of nitrogen oxides contained in the exhaust gas. Ammonia injection equipment for 2. A nitrogen oxide inlet concentration distribution comprising a plurality of ammonia injection systems for injecting ammonia with a plurality of mutually different injection concentration distributions, and selectively switching among the plurality of ammonia injection systems. 2. The ammonia injection apparatus for denitration according to claim 1, wherein ammonia can be injected with an injection concentration distribution corresponding to the following. 3. An inlet concentration distribution that the nitrogen oxides can take is two different inlet concentration distributions, and two ammonia injection systems capable of injecting ammonia with an injection concentration distribution corresponding to each inlet concentration distribution are provided. The ammonia injection apparatus for denitration according to claim 1 or 2, characterized in that: 4. The two inlet concentration distributions of nitrogen oxides include an inlet concentration distribution when a heating means provided near the upstream end of the gas path is burning, and an inlet concentration distribution when the heating means is not burning. The ammonia injection apparatus for denitration according to claim 3, wherein the ammonia injection apparatus has a distribution. 5. An ammonia injection system comprising: a supply source of ammonia; a distribution path for branching and supplying the ammonia supplied from the supply source to a plurality of branch conduits; A nozzle group composed of a plurality of nozzles for injecting the supplied ammonia into the exhaust gas. Each of the branch pipes of the distribution path has an injection amount of ammonia injected from the nozzle. The ammonia injection apparatus for denitration according to claim 1 or 2, further comprising an adjusting means for adjusting. 6. The ammonia injection system includes one supply source, two distribution lines branch-connected to the supply source, and one common supply line for the two distribution lines. The nozzle group of the system, and the adjusting means of each branch pipe of one of the distribution paths has an injection concentration distribution corresponding to one of the two inlet concentration distributions of the nitrogen oxide. It is possible to set the injection concentration corresponding to the other inlet concentration distribution of the two inlet concentration distributions of the nitrogen oxides. The ammonia injection apparatus for denitration according to claim 5, wherein the apparatus can be set to inject ammonia in a distribution. 7. A system comprising: one system of the supply source; two systems of the distribution paths branched and connected to the supply source; and two systems of the nozzle groups individually connected to each distribution path. The adjusting means of each branch pipe of one distribution path is set to inject ammonia at an injection concentration distribution corresponding to one of the two inlet concentration distributions of the nitrogen oxide. It is possible that the adjusting means of each branch pipe of the other distribution passage injects ammonia at an injection concentration distribution corresponding to the other inlet concentration distribution of the two inlet concentration distributions of the nitrogen oxide. The ammonia injection apparatus for denitration according to claim 5, wherein the apparatus can be set. 8. A system comprising two supply sources, two distribution paths individually connected to each supply source, and two nozzle groups individually connected to each distribution path. The adjusting means of each branch pipe of one distribution path is configured to inject ammonia at an injection concentration distribution corresponding to one of the two inlet concentration distributions of the nitrogen oxide. The adjusting means of each branch pipe of the other distribution passage is configured to inject ammonia at an injection concentration distribution corresponding to the other one of the two inlet concentration distributions of the nitrogen oxide. The ammonia injection apparatus for denitration according to claim 5, wherein the ammonia injection apparatus can be set to: 9. Between the supply source and each of the distribution paths,
The ammonia for denitration according to any one of claims 5 to 8, further comprising a switching shut-off means for shutting off the supply of ammonia as needed in order to selectively switch the ammonia injection system. Infusion device. 10. A supply shut-off means for shutting off the supply of ammonia as required at a position near each downstream end of each branch pipe of each distribution path. The ammonia injection apparatus for denitration according to any one of 5 to 8. 11. A plurality of nozzles of one nozzle group are suitable for injecting ammonia with an injection concentration distribution corresponding to one of the two inlet concentration distributions of the nitrogen oxide. Suitable for injecting ammonia into the plurality of nozzles of the other nozzle group at an injection concentration distribution corresponding to the other of the two inlet concentration distributions of the nitrogen oxide. The ammonia injection device for denitration according to any one of claims 5 to 8, wherein the ammonia injection device is arranged in a distributed manner. 12. The apparatus according to claim 5, further comprising an interlocking control unit that performs control for switching the distribution path in association with a combustion state or a non-combustion state of the heating unit.
9. The ammonia injection device for denitration according to any one of 8. 13. The ammonia injection apparatus for denitration according to claim 1, wherein the ammonia injected into the exhaust gas is liquefied ammonia, gaseous ammonia, or gas using ammonia water. 14. The ammonia for denitration according to claim 5, wherein said adjusting means is a damper for changing a degree of opening and closing of an internal path of said branch pipe. Infusion device.