JP2020124654A - Reductant feeder and application method therefor - Google Patents

Abstract

To prevent occurrence of topical unbalance in concentration distribution of a reductant by drift affection resulting from obstacles.SOLUTION: There is provided a reductant feeder feeding the reductant at the upstream side of an SCR catalyst in an exhaust flow path in which obstacles are disposed. The feeder comprises: plural injection nozzles disposed at intervals along one direction crossing with an exhaust flow direction in the downstream of the obstacle in the exhaust flow direction; and plural reductant feeding lines feeding the reductant to plural injection nozzles. Plural injection nozzles are plural that nozzle groups including at least one injection nozzle in which the reductant is fed by the same reductant feeding line when defining the nozzle located at the downstream of the obstacle among plural nozzles as a first injection nozzle, and that which is not located at the downstream as a second injection nozzle, and are partitioned into the first injection nozzle groups including the first nozzle and the second nozzle groups including the second nozzle.SELECTED DRAWING: Figure 2

Description

The present disclosure relates to a reducing agent supply device and a method of operating the reducing agent supply device.

Conventionally, in order to remove NOx from a combustion exhaust gas such as fossil fuel, a denitration agent that is mixed with a reducing agent such as ammonia in the exhaust gas and uses a denitration catalyst (such as an SCR catalyst) to accelerate the reaction The device is known. For example, in Patent Document 1, the direction and angle of the nozzle attached to the ammonia supply pipe are changed along the shape of the exhaust gas flow path of the exhaust gas duct so that the ammonia ejected from the nozzle is evenly distributed in the exhaust gas. A configured ammonia injector is disclosed.

JP, 9-24246, A

By the way, the denitration catalyst as described above is generally arranged over the entire width of the exhaust gas passage. Therefore, in order to make the concentration distribution of the reducing agent uniform in the width direction of the exhaust gas passage and to pass the catalyst, a plurality of nozzles may be arranged in the ammonia supply pipe at intervals in the extending direction of the supply pipe. On the other hand, various obstacles including pipes and struts may be arranged upstream of the ammonia supply pipe in the flow path. Since a nonuniform flow locally occurs in the downstream of such an obstacle, the concentration distribution of the reducing agent in the width direction becomes non-uniform in the downstream of the obstacle, and the denitration performance of the denitration catalyst may deteriorate.
In this regard, Patent Document 1 does not disclose any knowledge about the imbalance in the concentration distribution of the reducing agent due to the influence of the drift caused by the presence of the obstacle located upstream of the ammonia supply pipe.

In view of the above-mentioned circumstances, at least one embodiment of the present invention is a reducing agent supply device or a reducing agent supply device capable of suppressing an imbalance in the local concentration distribution of the reducing agent due to the influence of a drift caused by an obstacle. The purpose is to provide the operation method of.

(1) The reducing agent supply device according to at least one embodiment of the present invention is
A reducing agent supply device for supplying a reducing agent upstream of an SCR catalyst in an exhaust gas flow path in which an obstacle is arranged,
Downstream of the obstacle in the flow direction of the exhaust gas, a plurality of injection nozzles arranged at intervals along one direction intersecting the flow direction of the exhaust gas,
A plurality of reducing agent supply lines configured to supply the reducing agent to the plurality of injection nozzles,
Equipped with
Of the plurality of ejection nozzles, the ejection nozzle located downstream of the obstacle is defined as a first ejection nozzle, and the ejection nozzle not located downstream of the obstacle is defined as a second ejection nozzle,
The plurality of injection nozzles is a plurality of injection nozzle groups including at least one injection nozzle configured to supply the reducing agent through the same reducing agent supply line, and includes the first injection nozzle. It is divided into a first ejection nozzle group that is the ejection nozzle group and a plurality of ejection nozzle groups that include the second ejection nozzle group that is the ejection nozzle group that includes the second ejection nozzle.

According to the above configuration (1), the plurality of injection nozzles arranged in the exhaust gas flow path along one direction intersecting the flow direction of the exhaust gas are the first injections located downstream of the obstacle. It is divided into a first injection nozzle group including nozzles and an injection nozzle group including second injection nozzles that are not located downstream of the obstacle, and the reducing agent is supplied to each of the injection nozzle groups by the same reducing agent supply line. It Thereby, the injection amount of the reducing agent injected from the first injection nozzle group including the first injection nozzle located downstream of the obstacle can be adjusted independently of the second injection nozzle group. Therefore, even if a drift occurs downstream of the obstacle due to the presence of the obstacle, if the amount of the reducing agent supplied to the first injection nozzle group is appropriately adjusted, the flow is caused downstream of the injection nozzle group due to the drift. It is possible to suppress the imbalance in the local concentration distribution of the reducing agent in one direction that intersects with the flow direction of the exhaust gas, which occurs in step 1. That is, it is possible to provide a reducing agent supply device capable of suppressing an imbalance in the local concentration distribution of the reducing agent due to the influence of uneven flow due to an obstacle.

(2) In some embodiments, in the configuration of (1) above,
The number of the first injection nozzles included in one of the first injection nozzle groups may be smaller than the number of the second injection nozzles included in one of the second injection nozzle groups.

According to the above configuration (2), since the ratio of the first injection nozzle group to the flow passage cross-sectional area of the exhaust gas passage is smaller than that of the second injection nozzle group, the second injection nozzle group cannot cope with the flow passage. It is possible to more finely suppress the influence on the local concentration distribution of the reducing agent by an obstacle (for example, a thin pipe or strut) occupying a small portion of the cross-sectional area, and to make the concentration distribution uniform.

(3) In some embodiments, in the configuration of (1) or (2) above,
As a width W of the flow path in the one direction and a width D of the obstacle in the flow direction, a distance L between the obstacle and the first injection nozzle group in the flow direction is represented by the following formula (i) or ( ii) may be satisfied.
L≦2W (i)
L≦20D (ii)

At the downstream position that is sufficiently distant from the obstacle, the influence of the wake of the obstacle is small and the concentration distribution of the reducing agent in one direction intersecting the flow direction of the exhaust gas approaches a uniform value. The need for physical classification is reduced. On the other hand, at a position where the distance between the obstacle and the injection nozzle group is short and the influence of the wake is significant, the injection nozzle group is locally divided to effectively reduce the local imbalance of the concentration distribution. it can.
In this regard, according to the configuration of (3) above, by arranging the first injection nozzle group at a position satisfying the relationship of (i) or (ii) where the influence of the wake of the obstacle is large, the above (1) Alternatively, it is possible to maximize the effect described in (2).

(4) In some embodiments, in any one of the configurations (1) to (3) above,
The plurality of injection nozzles may be arranged discretely over the entire width of the flow path.

According to the above configuration (4), the concentration distribution of the reducing agent can be made uniform over the entire width of the exhaust gas passage. Therefore, for example, when the reducing agent supply device is arranged upstream of the SCR catalyst provided over the entire width of the flow path, the denitration performance of the SCR catalyst can be maximized by enjoying the effect described in (1) above. Can be maximized.

(5) In some embodiments, in any one of the configurations (1) to (4) above,
The reducing agent supply device is
A concentration sensor arranged downstream of the plurality of injection nozzle groups in the flow direction, for measuring the concentration distribution of the reducing agent in the exhaust gas in the one direction,
A plurality of flow rate adjusting valves provided corresponding to each of the plurality of reducing agent supply lines and a plurality of valve actuators capable of independently changing the opening degree of each of the plurality of flow rate adjusting valves;
The controller may further include a controller that drives the valve actuator so as to uniformize the concentration distribution of the reducing agent in the one direction according to the detection signal of the concentration sensor.

According to the above configuration (5), the controller feedback-controls each valve actuator in accordance with the detection signal from the concentration sensor so as to make the concentration distribution of the reducing agent uniform in one direction intersecting the flow direction of the exhaust gas. be able to. Thereby, for example, the concentration distribution of the reducing agent in one direction intersecting with the flow direction of the exhaust gas can be made uniform in real time without requiring an operator to individually adjust the opening degree of the valve.

(6) The operating method of the reducing agent supply device according to at least one embodiment of the present invention is
A method of operating a reducing agent supply device for supplying a reducing agent upstream of an SCR catalyst in an exhaust gas flow path in which an obstacle is arranged,
The reducing agent supply device,
Downstream of the obstacle in the flow direction of the exhaust gas, a plurality of injection nozzles arranged at intervals along one direction intersecting the flow direction of the exhaust gas,
A plurality of reducing agent supply lines configured to supply the reducing agent to the plurality of injection nozzles,
Equipped with
Of the plurality of ejection nozzles, the ejection nozzle located downstream of the obstacle is defined as a first ejection nozzle, and the ejection nozzle not located downstream of the obstacle is defined as a second ejection nozzle,
The plurality of injection nozzles is a plurality of injection nozzle groups including at least one injection nozzle configured to supply the reducing agent through the same reducing agent supply line, and includes the first injection nozzle. A plurality of ejection nozzle groups including a first ejection nozzle group that is the ejection nozzle group and a second ejection nozzle group that is the ejection nozzle group that includes the second ejection nozzle;
The operating method of the reducing agent supply device is
Measuring the concentration distribution of the reducing agent or NOx in the one direction downstream of the plurality of injection nozzles in the flow direction of the exhaust gas;
Adjusting the amount of the reducing agent supplied to the first injection nozzle group and the second injection nozzle group individually according to the measurement result of the concentration distribution.

According to the method of (6), as described in (1) above, a plurality of injection nozzles arranged in the exhaust gas passage along one direction intersecting the flow direction of the exhaust gas, The jet nozzle group is divided into a first jet nozzle group including a first jet nozzle located downstream of the obstacle and a jet nozzle group including a second jet nozzle not located downstream of the obstacle. The reducing agent is supplied by the reducing agent supply line. Thereby, the injection amount of the reducing agent injected from the first injection nozzle group including the first injection nozzle located downstream of the obstacle can be adjusted independently of the second injection nozzle group. Therefore, even if a drift occurs downstream of the obstacle due to the presence of the obstacle, if the amount of the reducing agent supplied to the first injection nozzle group is appropriately adjusted, the flow is caused downstream of the injection nozzle group due to the drift. It is possible to suppress the imbalance in the local concentration distribution of the reducing agent in one direction that intersects with the flow direction of the exhaust gas, which occurs in step 1. That is, it is possible to provide a method for operating a reducing agent supply device capable of suppressing an imbalance in the local concentration distribution of the reducing agent due to the effect of drift caused by an obstacle. Further, as described in (5) above, the first injection nozzle group and the second injection nozzles are arranged according to the concentration distribution of the reducing agent in one direction intersecting the flow direction of the exhaust gas measured downstream of the plurality of injection nozzles. The amount of reducing agent supplied to the group can be adjusted individually. Thereby, for example, the concentration distribution of the reducing agent in one direction intersecting with the flow direction of the exhaust gas can be made uniform without requiring an operator to adjust the opening degree of each injection nozzle.

According to at least one embodiment of the present invention, there is provided a reducing agent supply device capable of suppressing an unbalance of the local concentration distribution of the reducing agent due to the influence of a drift caused by an obstacle, and a method of operating the reducing agent supply device. can do.

It is the schematic which shows the structure of the exhaust gas flow path downstream of the boiler system to which the reducing agent supply apparatus which concerns on one Embodiment of this invention is applied. It is a side sectional view showing roughly the composition of the reducing agent supply unit concerning one embodiment. It is a figure which shows schematically the structure of the reducing agent supply apparatus which concerns on one Embodiment, and is a partial expanded view of the III section shown in FIG. It is a sectional side view which shows roughly the density|concentration adjustment of the reducing agent by the reducing agent supply apparatus which concerns on one Embodiment. It is a block diagram which shows the structure of the control system in the reducing agent supply apparatus which concerns on one Embodiment. It is a flow chart which shows the reducing agent supply method concerning at least one embodiment of the present invention.

Hereinafter, some embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described as the embodiments or shown in the drawings are not intended to limit the scope of the present invention thereto, but are merely illustrative examples. Absent.
For example, the expressions representing relative or absolute arrangements such as "in a certain direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric", or "coaxial" are strict. In addition to representing such an arrangement, it also represents a state of relative displacement, or a state of relative displacement with an angle or a distance at which the same function can be obtained.
Further, for example, an expression representing a shape such as a quadrangle or a cylindrical shape does not only represent a shape such as a quadrangle or a cylindrical shape in a geometrically strict sense, but also an uneven portion or The shape including the chamfered portion and the like is also shown.
On the other hand, the expressions “comprising”, “comprising”, “comprising”, “including”, or “having” one element are not exclusive expressions excluding the existence of other elements.

FIG. 1 is a schematic diagram showing a configuration on a downstream side of an exhaust gas passage of a boiler system to which a reducing agent supply device 10 according to at least one embodiment of the present invention is applied.
In the following description, as an example, the case where the denitration device 1 is arranged in the exhaust gas passage 2 of the coal-fired boiler (boiler 4) will be described. The boiler 4 includes a furnace 5 and a combustion device (not shown) shown in FIG. 1, and a flue 6 continuing to the exhaust gas passage 2.

As shown in FIG. 1, the denitration device 1 is arranged downstream of the exhaust gas flow path 2 of the boiler system 100. The denitration device 1 extends along the direction intersecting the flow direction of the exhaust gas G (that is, the width direction of the exhaust gas flow path 2) on the downstream side in the exhaust gas flow path 2 that guides the exhaust gas G discharged from the boiler 4. And a reducing agent 8 (for example, anhydrous ammonia, ammonia water, urea, urea water, or a mixture of at least one of these with air) upstream of the SCR catalyst 3 in the exhaust gas flow path 2. A reducing agent supply device 10 for supplying a gas or the like). In the following description, it is assumed that ammonia (more specifically, a mixed gas of ammonia and air) is sprayed into the exhaust gas G as an example of the reducing agent 8.

The SCR catalyst 3 is a denitration catalyst used in a selective catalytic reduction (SCR) denitration device, and, for example, nitrogen oxides (NOx) in exhaust gas G produced by combustion of a carbon-containing fuel and reduction, It is configured to promote the reaction with the reducing agent 8 supplied from the agent supply device 10 to remove the NOx component in the exhaust gas G. Although a detailed description of the SCR catalyst 3 is omitted, the SCR catalyst 3 is configured by using, for example, various ceramics or titanium oxide as a carrier.

The reducing agent supply device 10 is a device for spraying the reducing agent 8 described above into the exhaust gas passage 2. The reducing agent supply device 10 described in the present disclosure is configured to inject ammonia such that the concentration distribution of ammonia becomes uniform in the direction intersecting the flow direction of the exhaust gas G.

Next, the reducing agent supply device 10 according to at least one embodiment of the present invention will be described.
FIG. 2 is a side sectional view schematically showing the configuration of the reducing agent supply device according to the embodiment. FIG. 3 is a diagram schematically showing the configuration of the reducing agent supply device according to the embodiment, and is a partially enlarged view of a III portion shown in FIG. 2.
As illustrated in FIGS. 2 and 3, the reducing agent supply device 10 according to at least one embodiment of the present invention is a device that is also called an ammonia injection device or an ammonia injection grid (AIG), and has an internal structure. In addition, at least one header pipe 12 that is configured to allow ammonia to flow and extends into the exhaust gas flow path 2 is provided. Further, the reducing agent supply device 10 is a reducing agent supply device 10 for supplying the reducing agent 8 upstream of the SCR catalyst 3 in the flow path of the exhaust gas G (exhaust gas flow path 2) in which the obstacle 7 is arranged. Then, in the downstream of the obstacle 7 in the flow direction of the exhaust gas G, the plurality of injection nozzles 20 arranged at intervals along one direction intersecting the flow direction of the exhaust gas G, and the plurality of injection nozzles 20 are provided. A plurality of reducing agent supply lines 30 configured to supply the reducing agent 8 thereto.

The plurality of injection nozzles 20 are respectively arranged in the header pipe 12 on the downstream side in the flow direction of the exhaust gas G with respect to the header pipe 12, and are arranged so as to inject the reducing agent 8 toward the downstream side. There is. For example, the plurality of injection nozzles 20 may be arranged at equal intervals along the extending direction of the header tube 12.
Among the plurality of ejection nozzles 20, among the plurality of ejection nozzles 20, the ejection nozzle 20 located downstream of the obstacle 7 is the first ejection nozzle 21A and the ejection nozzle 20 not located downstream of the obstacle 7 is the first ejection nozzle 20. When defined as two injection nozzles 22A, a plurality of injection nozzle groups 24 including at least one injection nozzle 20 configured to supply the reducing agent 8 by the same reducing agent supply line 30, It is divided into a first jet nozzle group 21 which is a jet nozzle group 24 including the jet nozzle 21A, and a plurality of jet nozzle groups 24 which includes a second jet nozzle group 22 which is a jet nozzle group 24 including the second jet nozzle 22A. It

For example, the first injection nozzle group 21 is arranged in the first header pipe segment 12A that is wider in one direction than the downstream projection of the obstacle 7 located upstream of the first injection nozzle group 21 in the exhaust gas flow path 2. May be. In this case, the second injection nozzle 22A may be arranged in the second header pipe segment 12B wider in the one direction than the first header pipe segment 12B. Each header pipe segment 12A, 12B may include an internal flow path for guiding the reducing agent supplied from each reducing agent supply line 30 to each injection nozzle 20.

The plurality of reducing agent supply lines 30 may branch from a main supply line (not shown) and extend into the exhaust gas passage 2, and are configured to supply the reducing agent to the corresponding injection nozzle groups 24. Can be done.

According to the reducing agent supply device 10 configured as described above, the plurality of injection nozzles 20 arranged in the flow path 2 of the exhaust gas G along one direction intersecting the flow direction of the exhaust gas G, The jetting is divided into a first jetting nozzle group 21 including a first jetting nozzle 21A located downstream of the obstacle 7 and a jetting nozzle group 24 including a second jetting nozzle 22A not located downstream of the obstacle 7 and each jetting. The reducing agent 8 is supplied to the nozzle group 24 through the same reducing agent supply line 30. Thereby, the injection amount of the reducing agent 8 injected from the first injection nozzle group 21 including the first injection nozzle 21A located downstream of the obstacle 7 can be adjusted independently of the second injection nozzle group 22. Therefore, even if a drift occurs downstream of the obstacle 7 due to the presence of the obstacle 7, if the amount of the reducing agent 8 supplied to the first injection nozzle group 21 is appropriately adjusted, the injection is caused due to the drift. It is possible to suppress the imbalance in the local concentration distribution of the reducing agent 8 in one direction that intersects the flow direction of the exhaust gas G, which occurs downstream of the nozzle group 24. That is, it is possible to provide the reducing agent supply device 10 capable of suppressing the imbalance of the local concentration distribution of the reducing agent 8 due to the influence of the drift caused by the obstacle 7.

In the above configuration, in some embodiments, as illustrated in FIG. 3, for example, the number of the first injection nozzles 21A included in one first injection nozzle group 21 is included in one second injection nozzle group 22. The number may be smaller than the number of second injection nozzles 22A that are provided.

According to the configuration in which the number of the first injection nozzles 21A included in the one first injection nozzle group 21 is smaller than the number of the second injection nozzles 22A included in the one second injection nozzle group 22 as described above, the exhaust gas Since the ratio of the first injection nozzle group 21 to the flow path cross-sectional area of the flow path 2 is smaller than that of the second injection nozzle group 22, the second injection nozzle group 22 cannot deal with the problem, and the ratio to the flow path cross-sectional area is small. It is possible to more finely suppress the influence of the object 7 (for example, a thin pipe or a strut) on the local concentration distribution of the reducing agent 8, and to make the concentration distribution uniform.

In any one of the configurations described above, in some embodiments, as illustrated in, for example, FIGS. 2 and 3, the width W of the exhaust gas passage 2 in one direction intersecting the flow direction of the exhaust gas G, the flow As the width D of the obstacle 7 in the direction, the distance L between the obstacle 7 and the first injection nozzle group 21 in the flow direction may satisfy the following expression (i) or (ii).
L≦2W (i)
L≦20D (ii)

That is, a distance L between the obstacle 7 and the injection nozzle group 24 including the first injection nozzle group 21 and the second injection nozzle group 22 along the exhaust gas flow path 2 is approximately twice the width W of the exhaust gas flow path 2 or less. The width may be about 20 times or less of the width D of the obstacle 7 (for example, the outer diameter of the obstacle when the pipe or the like is the obstacle 7).

Here, at a downstream position sufficiently distant from the obstacle 7, the influence of the wake of the obstacle 7 is small, and the concentration distribution of the reducing agent 8 in one direction intersecting with the flow direction of the exhaust gas G becomes closer to uniform. Therefore, the necessity of locally dividing the injection nozzle group 24 is reduced. On the other hand, when the distance between the obstacle 7 and the injection nozzle group 24 is short and the influence of the wake is significant, the injection nozzle group 24 is locally divided to effectively reduce the imbalance in the local concentration distribution. can do.
In this respect, as described above, the width W of the exhaust gas passage 2, the width D of the obstacle 7 in the flow direction of the exhaust gas G, and the distance L between the obstacle 7 and the first injection nozzle group 21 in the flow direction are as described above. According to the configuration that satisfies the expression (i) or the expression (ii), the first injection nozzle group 21 is arranged at a position that satisfies the relationship of the expression (i) or the expression (ii) where the influence of the wake of the obstacle 7 is large. As a result, the effect described in any one of the above-described embodiments can be maximized.
The distance L in the above formula (i) or (ii) may be set such that the downstream end of the header pipe 12, that is, the base end of the injection nozzle 20 in the flow direction of the exhaust gas G may be the downstream end. The downstream end of 20 may be the downstream end. The downstream end of the obstacle 7 may be applied to the upstream end of the distance L, or the center of the obstacle 7 (for example, the centroid of the obstacle 7 in FIG. 3) may be the upstream end. ..

In any one of the above-described configurations, in some embodiments, for example, as illustrated in FIG. 3, the first injection nozzle group 21 includes, for example, the flow direction of the exhaust gas G or the pipe axis of the exhaust gas passage 2. When the angular range of the drift caused by the obstacle 7 is θ, the injection nozzle 20 included in the range of D+2Lsin θ with respect to the width W direction of the exhaust gas passage 2 may be included as the first injection nozzle 21A.
Further, in some embodiments, for example, the injection nozzles 20 that are displaced in the one direction with respect to the projection of the obstacle 7 located upstream of the first injection nozzle group 21 in the flow direction are replaced by the first injection nozzles. It may be defined as 21A. For example, the first injection nozzle 21A may be arranged so as to entirely overlap the projection of the obstacle 7 toward the downstream side of the exhaust gas passage 2 in the pipe axis direction of the exhaust gas passage 2. .. Further, the first injection nozzle 21A may be arranged so that at least a part of the first injection nozzle 21A overlaps the projection of the obstacle 7 when viewed in the pipe axis direction of the exhaust gas flow path 2. Further, the first injection nozzle 21A may be arranged so as to be displaced in the width direction of the exhaust gas flow channel 2 so as not to overlap with the above projection.
The first injection nozzle group 21 is located immediately adjacent to the projection of the obstacle 7 located upstream in the width direction of the exhaust gas passage 2 (one direction intersecting with the flow direction of the exhaust gas G). The ejection nozzle 20 may be included as the first ejection nozzle 21A. Alternatively, the first injection nozzle group 21 may include, as the first injection nozzle 21A, one or a plurality of injection nozzles 20 included in a range that may be affected by the wake of the obstacle 7 located upstream.

Here, the drift caused by the obstacle 7 can be variously changed depending on the shape of the obstacle 7, the distance L between the obstacle 7 and the injection nozzle 20, the flow velocity of the exhaust gas G, and the like. There is a possibility that the concentration distribution cannot be efficiently made uniform simply by adjusting the injection amount from the injection nozzle 20 arranged at the strictly downstream position of the obstacle 7.
In this respect, according to the above configuration, the first injection nozzle 21A including the first injection nozzle 21A arranged so as to be displaced in one direction intersecting the flow direction of the exhaust gas G with respect to the projection of the obstacle 7 in the flow direction of the exhaust gas G is provided. The supply amount of the reducing agent 8 to the one injection nozzle group 21 can be individually adjusted. Therefore, the degree of freedom in design when deciding the injection nozzles 20 to be divided into the first injection nozzle group 21 among the plurality of injection nozzles 20 according to various arrangements and designs of the obstacles 7 and the like in the exhaust gas flow path 2 is provided. Can be improved.

FIG. 4 is a side sectional view schematically showing concentration adjustment of the reducing agent by the reducing agent supply device according to the embodiment.
In any one of the configurations described above, in some embodiments, as illustrated in, for example, FIGS. 2 to 4, the plurality of injection nozzles 20 are discretely arranged over the entire width of the exhaust gas passage 2. May be. The intervals between the injection nozzles 20 and the number of the injection nozzles 20 in the width direction of the exhaust gas passage 2 may be set arbitrarily.

As described above, according to the configuration in which the plurality of injection nozzles 20 are discretely arranged over the entire width of the exhaust gas passage 2, the concentration distribution of the reducing agent 8 is made uniform over the entire width of the exhaust gas passage 2. be able to. Therefore, for example, when the reducing agent supply device 10 is arranged upstream of the SCR catalyst 3 provided over the entire width of the exhaust gas passage 2, the reducing agent concentration distribution in the width direction of the exhaust gas passage 2 is made uniform. It is possible to maximize the effect and maximize the denitration performance of the SCR catalyst 3.
The plurality of injection nozzles 20 may be divided into flow velocity regions in which the flow velocity of the exhaust gas G is different in the width direction of the exhaust gas passage 2 as illustrated in FIG. 4, for example.

FIG. 5 is a block diagram showing a configuration of a control system in the reducing agent supply device according to the embodiment.
In any one of the configurations described above, in some embodiments, as illustrated in, for example, FIG. 2, FIG. 4, and FIG. 5, the reducing agent supply device 10 is disposed downstream of the plurality of injection nozzle groups 24 in the flow direction. A concentration sensor 40 arranged to measure the concentration distribution of the reducing agent 8 in the exhaust gas G in one direction intersecting the flow direction of the exhaust gas G and a plurality of reducing agent supply lines 30 are provided corresponding to each. The plurality of flow rate adjusting valves 32 and the plurality of valve actuators 34 capable of independently changing the opening of each of the plurality of flow rate adjusting valves 32, and the flow direction of the exhaust gas G depending on the detection signal of the concentration sensor 40. The controller 50 which drives the valve actuator 34 so as to make the concentration distribution of the reducing agent 8 uniform in one direction may be further provided.

The concentration sensor 40 may be configured to measure the concentration distribution of the reducing agent in the width direction of the exhaust gas passage 2, for example.

The controller 50 is, for example, a computer, and includes a CPU 51, a ROM (Read Only Memory) 53 as a storage unit for storing various programs executed by the CPU 51 and data such as a table, a development area for executing each program, In addition to a RAM (Random Access Memory) 52 which functions as a work area such as a calculation area, a hard disk drive (HDD) as a mass storage device (not shown), a communication interface for connecting to a communication network, and an external storage device are mounted. It may be provided with an access unit or the like. All of these are connected via a bus 55. Further, the controller 50 may be connected to, for example, an input unit (not shown) including a keyboard, a mouse, a touch panel, etc., a display unit (not shown) including a liquid crystal display device for displaying data, and the like.

In some embodiments, in the ROM 53, each valve actuator 34 is driven so that the concentration of the reducing agent becomes uniform in the width direction of the exhaust gas passage 2 in response to a detection signal from the concentration sensor 40, for example. The reducing agent injection amount adjustment for adjusting the opening degree of the flow rate adjusting valve 32 and adjusting the injection amount of the reducing agent injected from the injection nozzle 20 of each of the first injection nozzle group 21 or the second injection nozzle group 22. The program 54 may be stored.

According to the configuration further including the concentration sensor 40, the flow rate adjusting valve 32, the valve actuator 34, and the controller 50 in this way, the controller 50 is unidirectional in which the controller 50 intersects the flow direction of the exhaust gas G according to the detection signal from the concentration sensor 40. The respective valve actuators 34 can be feedback-controlled so as to make the concentration distribution of the reducing agent 8 in the above equation uniform. As a result, the concentration distribution of the reducing agent 8 in one direction intersecting the flow direction of the exhaust gas G can be made uniform in real time without requiring, for example, an operator to adjust the opening degree of the individual flow rate adjusting valve 32.

Next, a reducing agent supply method according to at least one embodiment of the present invention will be described.
FIG. 6 is a flowchart showing a reducing agent supply method according to at least one embodiment of the present invention.
As illustrated in FIG. 6, the operating method of the reducing agent supply device 10 according to at least one embodiment of the present invention is to install the reducing agent 8 upstream of the SCR catalyst 3 in the exhaust gas passage 2 in which the obstacle 7 is arranged. It is an operating method of the reducing agent supply device 10 for supplying.
The reducing agent supply apparatus 10 in this method includes a plurality of injection nozzles 20 arranged at intervals downstream of the obstacle 7 in the flow direction of the exhaust gas G along one direction intersecting with the flow direction of the exhaust gas G. And a plurality of reducing agent supply lines 30 configured to supply the reducing agent 8 to the plurality of injection nozzles 20. Among the plurality of ejection nozzles 20, when the ejection nozzle 20 located downstream of the obstacle 7 is defined as the first ejection nozzle 21A and the ejection nozzle 20 not located downstream of the obstacle 7 is defined as the second ejection nozzle 22A, a plurality of ejection nozzles The injection nozzle 20 of No. 1 is a plurality of injection nozzle groups 24 including at least one injection nozzle 20 configured to supply the reducing agent 8 by the same reducing agent supply line 30, and includes the first injection nozzle 21A. It is divided into a plurality of ejection nozzle groups 24 including a first ejection nozzle group 21 which is an ejection nozzle group 24 including the same, and a second ejection nozzle group 22 which is an ejection nozzle group 24 including a second ejection nozzle 22A.
Then, the operating method of the reducing agent supply device 10 is a step of measuring the concentration distribution of the reducing agent 8 or NOx in one direction that intersects the flow direction of the exhaust gas G downstream of the plurality of injection nozzles 20 in the flow direction of the exhaust gas G. (Step S10) and a step (Step S20) of individually adjusting the amount of the reducing agent 8 to be supplied to the first injection nozzle group 21 and the second injection nozzle group 22 according to the measurement result of the concentration distribution. I have it.

According to this method, the plurality of injection nozzles 20 arranged in the flow path 2 of the exhaust gas G along one direction intersecting with the flow direction of the exhaust gas G are located at the downstream side of the obstacle 7. It is divided into a first injection nozzle group 21 including the injection nozzle 21A and an injection nozzle group 24 including a second injection nozzle 22A that is not located downstream of the obstacle 7, and the same reducing agent is supplied to each injection nozzle group 24. The reducing agent 8 is supplied through the line 30. Thereby, the injection amount of the reducing agent 8 injected from the first injection nozzle group 21 including the first injection nozzle 21A located downstream of the obstacle 7 can be adjusted independently of the second injection nozzle group 22. Therefore, even if a drift occurs downstream of the obstacle 7 due to the presence of the obstacle 7, if the amount of the reducing agent 8 supplied to the first injection nozzle group 21 is appropriately adjusted, the injection is caused due to the drift. It is possible to suppress an imbalance in the local concentration distribution of the reducing agent 8 in one direction that intersects with the flow direction of the exhaust gas G, which occurs downstream of the nozzle group 24. Further, the first injection nozzle group is configured to make the concentration distribution of the reducing agent 8 uniform according to the concentration distribution of the reducing agent 8 in one direction intersecting the flow direction of the exhaust gas G measured downstream of the plurality of injection nozzles 20. 21 and the amount of the reducing agent 8 supplied to the second injection nozzle group 22 can be individually adjusted. As a result, the concentration distribution of the reducing agent 8 in one direction intersecting the flow direction of the exhaust gas G can be made uniform without requiring, for example, an operator to adjust the opening degree of each individual injection nozzle 20.

According to at least one embodiment of the present invention described above, the reducing agent supply device 10 and the reducing agent supply capable of suppressing the imbalance of the local concentration distribution of the reducing agent 8 due to the influence of the drift caused by the obstacle 7. A method of operating the device 10 can be provided.

The present invention is not limited to the above-described embodiment, and includes a modified form of the above-described embodiment and a combination of these forms as appropriate.

1 DeNOx device 2 Exhaust gas flow path (flow path/flue)
3 SCR catalyst (DeNOx catalyst)
4 Boiler 5 Furnace 6 Flue 7 Obstacle 8 Reducing agent 10 Reducing agent supplying device 12 Header pipe 12A First header pipe segment 12B Second header pipe segment 20 Injection nozzle 21 First injection nozzle group 21A First injection nozzle 22 Second Injection nozzle group 22A Second injection nozzle 24 Injection nozzle group 30 Reductant supply line 32 Flow rate adjusting valve 34 Valve actuator 40 Concentration sensor 50 Controller 51 CPU
52 RAM
53 ROM
54 Reducing agent injection amount adjustment program 55 Bus 100 Boiler system G Exhaust gas

Claims (6)

A reducing agent supply device for supplying a reducing agent upstream of an SCR catalyst in an exhaust gas flow path in which an obstacle is arranged,
Downstream of the obstacle in the flow direction of the exhaust gas, a plurality of injection nozzles arranged at intervals along one direction intersecting the flow direction of the exhaust gas,
A plurality of reducing agent supply lines configured to supply the reducing agent to the plurality of injection nozzles,
Equipped with
Of the plurality of ejection nozzles, the ejection nozzle located downstream of the obstacle is defined as a first ejection nozzle, and the ejection nozzle not located downstream of the obstacle is defined as a second ejection nozzle,
The plurality of injection nozzles is a plurality of injection nozzle groups including at least one injection nozzle configured to supply the reducing agent through the same reducing agent supply line, and includes the first injection nozzle. A reducing agent supply device divided into a first injection nozzle group that is the injection nozzle group and a plurality of injection nozzle groups that include the second injection nozzle group that is the injection nozzle group that includes the second injection nozzle. The reducing agent supply according to claim 1, wherein the number of the first injection nozzles included in one of the first injection nozzle groups is smaller than the number of the second injection nozzles included in one of the second injection nozzle groups. apparatus. As a width W of the flow path in the one direction and a width D of the obstacle in the flow direction, a distance L between the obstacle and the first injection nozzle group in the flow direction is represented by the following formula (i) or ( The reducing agent supply device according to claim 1 or 2, which satisfies ii).
L≦2W (i)
L≦20D (ii) The reducing agent supply device according to claim 1, wherein the plurality of injection nozzles are discretely arranged over the entire width of the flow path. A concentration sensor arranged downstream of the plurality of injection nozzle groups in the flow direction, for measuring the concentration distribution of the reducing agent or NOx in the exhaust gas in the one direction,
A plurality of flow rate adjusting valves provided corresponding to each of the plurality of reducing agent supply lines and a plurality of valve actuators capable of independently changing the opening degree of each of the plurality of flow rate adjusting valves;
The reducing agent supply device according to claim 1, further comprising a controller that drives the valve actuator according to a detection signal of the concentration sensor. A method of operating a reducing agent supply device for supplying a reducing agent upstream of an SCR catalyst in an exhaust gas flow path in which an obstacle is arranged,
The reducing agent supply device,
Downstream of the obstacle in the flow direction of the exhaust gas, a plurality of injection nozzles arranged at intervals along one direction intersecting the flow direction of the exhaust gas,
A plurality of reducing agent supply lines configured to supply the reducing agent to the plurality of injection nozzles,
Equipped with
Of the plurality of ejection nozzles, the ejection nozzle located downstream of the obstacle is defined as a first ejection nozzle, and the ejection nozzle not located downstream of the obstacle is defined as a second ejection nozzle,
The plurality of injection nozzles is a plurality of injection nozzle groups including at least one injection nozzle configured to supply the reducing agent through the same reducing agent supply line, and includes the first injection nozzle. A plurality of ejection nozzle groups including a first ejection nozzle group that is the ejection nozzle group and a second ejection nozzle group that is the ejection nozzle group that includes the second ejection nozzle;
The operating method of the reducing agent supply device is
Measuring the concentration distribution of the reducing agent or NOx in the one direction downstream of the plurality of injection nozzles in the flow direction of the exhaust gas;
Adjusting the amount of the reducing agent supplied to the first injection nozzle group and the second injection nozzle group individually according to the measurement result of the concentration distribution.

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