TWI707719B - Reducing agent supply device and method of operating the reducing agent supply device - Google Patents

Abstract

The subject of the present invention is to suppress the unevenness of the local concentration distribution of the reducing agent caused by the influence of the drift of the obstacle. The reductant supply device of the present invention supplies reductant to the upstream of the SCR catalyst in the exhaust gas flow path where the obstacle is arranged, and is equipped with a plurality of injection nozzles, which are downstream of the obstacle in the flow direction of the exhaust gas. It is arranged at intervals in a direction crossing the flow direction of the exhaust gas; and a plurality of reducing agent supply lines which supply the reducing agent to the plurality of injection nozzles. In the case of plural spray nozzles, the spray nozzle located downstream of the obstacle is defined as the first spray nozzle, and the spray nozzle not located downstream is defined as the second spray nozzle, the plural spray nozzles are divided into plural An injection nozzle group, the plurality of injection nozzle groups including at least one injection nozzle that supplies the reducing agent from the same reducing agent supply line, and includes: a first injection nozzle group, which is an injection nozzle group containing the first injection nozzle, And the second jet nozzle group is a jet nozzle group including the second jet nozzle.

Description

Reducing agent supply device and method of operating the reducing agent supply device

The invention relates to a reducing agent supply device and an operating method of the reducing agent supply device.

A denitrification device is previously known, for example, in order to remove NOx from combustion exhaust gas of fossil fuels, etc., a reducing agent such as ammonia is mixed into the exhaust gas, and a denitrification catalyst (such as an SCR catalyst) is used to promote the reaction. For example, Patent Document 1 discloses an ammonia injection device, which is configured to change the orientation and angle of the nozzle installed in the ammonia supply pipe along the shape of the exhaust gas flow path of the exhaust pipe, so that the ammonia sprayed from the nozzle is uniformly distributed in the exhaust gas in. [Prior Technical Document] [Patent Document]

[Patent Document 1] Japanese Patent Application Laid-Open No. 9-24246

[The problem to be solved by the invention]

However, the denitration catalyst as described above is usually arranged across the entire width of the exhaust gas flow path. Therefore, in order to make the concentration distribution of the reducing agent in the width direction of the exhaust gas flow path uniform and allow the catalyst to pass through, a plurality of nozzles are arranged in the ammonia supply pipe at intervals in the extending direction of the supply pipe. On the other hand, various obstacles including pipes or pillars are arranged upstream of the ammonia supply pipe in the flow path. Since a partial flow is locally generated in the downstream of such an obstacle, the concentration distribution of the reducing agent in the width direction becomes non-uniform downstream of the obstacle, and the denitration performance of the denitration catalyst may decrease. Regarding this point, Patent Document 1 does not disclose any knowledge about the unbalanced concentration distribution of the reducing agent due to the influence of the bias current caused by the presence of obstacles located upstream of the ammonia supply pipe.

In view of the above-mentioned situation, the object of at least one embodiment of the present invention is to provide a reducing agent supply device or reducing agent that can suppress the uneven local concentration distribution of the reducing agent caused by the influence of the drift of obstacles How to use the supply device. [Technical means to solve the problem]

(1) The reducing agent supply device of at least one embodiment of the present invention is used for supplying the reducing agent upstream of the SCR catalyst in the flow path of the exhaust gas with obstacles, and has: A plurality of injection nozzles are arranged at intervals along a direction crossing the flow direction of the exhaust gas downstream of the obstacle in the flow direction of the exhaust gas; and A plurality of reducing agent supply lines are configured to supply the aforementioned reducing agent to the aforementioned plurality of injection nozzles; and In the case where the jet nozzle located downstream of the obstacle among the plurality of jet nozzles is defined as the first jet nozzle, and the jet nozzle not located downstream of the obstacle is defined as the second jet nozzle, The plurality of injection nozzles is divided into a plurality of injection nozzle groups including at least one injection nozzle configured to supply the reducing agent from the same reducing agent supply line, and includes the injection nozzle group including the first injection nozzle, namely The first spray nozzle group and a plurality of spray nozzle groups including the second spray nozzle group, which is the spray nozzle group of the second spray nozzle.

According to the configuration of (1) above, the plurality of injection nozzles arranged in a direction that intersects the flow direction of the exhaust gas in the flow path of the exhaust gas are divided into those including the first injection nozzle located downstream of the obstacle The first injection nozzle group and the injection nozzle group including the second injection nozzle not located downstream of the obstacle are supplied with a reducing agent through the same reducing agent supply line to each of the injection nozzle groups. 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 from the second injection nozzle group. Therefore, even if it is assumed that a drift is generated downstream of the obstacle due to the existence of the obstacle, if the amount of reducing agent supplied to the first injection nozzle group is appropriately adjusted, it is possible to suppress the drift in the injection nozzle due to the drift. The local concentration distribution of the reducing agent in a direction that crosses the flow direction of the exhaust gas generated downstream of the cluster is uneven. In other words, it is possible to provide a reducing agent supply device capable of suppressing the unevenness of the local concentration distribution of the reducing agent caused by the influence of the drift of the obstacle.

(2) In several embodiments, it is constituted as in (1) above, in which The number of the first spray nozzles included in one first spray nozzle group may be less than the number of the second spray nozzles included in one second spray nozzle group.

According to the configuration of (2) above, since the ratio of the first injection nozzle group to the cross-sectional area of the exhaust gas flow path is smaller than that of the second injection nozzle group, it is possible to more finely suppress the problems that cannot be handled by the second injection nozzle group Because the proportion of the cross-sectional area of the flow path is small obstacles (such as thin pipes or pillars, etc.) that affect the concentration distribution of the local reducing agent, the concentration distribution is uniformed.

(3) In several embodiments, it is the composition of (1) or (2) above, where As the width W of the flow path in the one direction, the width D of the obstacle in the flow direction, and the distance L between the obstacle in the flow direction and the first jet nozzle group, the following formula (i ) Or (ii). L≦2W・・・(i) L≦20D・・・(ii)

Since the downstream position of the obstacle is sufficiently far away from the obstacle, the influence of the downstream flow of the obstacle is small, and the concentration distribution of the reducing agent in a direction crossing with the flow direction of the exhaust gas is close to uniform, so it is necessary to locally distinguish the spray nozzle groups reduce. On the other hand, by locally distinguishing the spray nozzle groups at locations where the distance between the obstacle and the spray nozzle group is close, and the influence of the backflow is significant, the unevenness of the local concentration distribution can be effectively reduced. In this regard, according to the configuration of (3) above, by arranging the first jet nozzle group at a position that satisfies the relationship of (i) or (ii), which has a large influence on the flow after the obstacle, the above-mentioned ( The effect described in 1) or (2).

(4) In several embodiments, it is constituted by any one of (1) to (3) above, wherein The plurality of spray nozzles may be discretely arranged over the entire width of the flow path.

According to the configuration of (4) above, the concentration distribution of the reducing agent can be made uniform across the entire width of the exhaust gas flow path. Therefore, for example, in the case where a reducing agent supply device is arranged upstream of the SCR catalyst that is installed across the entire width of the flow path, the effect described in (1) above can be enjoyed to the fullest, so as to maximize the SCR The denitration performance of the catalyst.

(5) In several embodiments, it is constituted by any one of (1) to (4) above, wherein The reducing agent supply device can be further equipped with: A concentration sensor, which is 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 adjustment valves corresponding to each of the aforementioned 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 adjustment valves; and A controller that drives the valve actuator in a manner that uniformizes the concentration distribution of the reducing agent in the one direction according to the detection signal of the concentration sensor.

According to the configuration of (5) above, the controller can perform feedback control on each valve actuator based on the detection signal from the concentration sensor to uniformize the concentration distribution of the reducing agent in a direction crossing the flow direction of the exhaust gas. . Thereby, it is possible to instantly uniformize the concentration distribution of the reducing agent in a direction crossing the flow direction of the exhaust gas without the need for an individual valve opening adjustment operation performed by the operator, for example.

(6) The operating method of the reducing agent supply device of at least one embodiment of the present invention, It is used for a reducing agent supply device which is used to supply the reducing agent upstream of the SCR catalyst in the exhaust gas flow path with obstacles, and The aforementioned reducing agent supply device includes: A plurality of injection nozzles are arranged at intervals along a direction crossing the flow direction of the exhaust gas downstream of the obstacle in the flow direction of the exhaust gas; and A plurality of reducing agent supply lines are configured to supply the aforementioned reducing agent to the aforementioned plurality of injection nozzles; and In the case where the jet nozzle located downstream of the obstacle among the plurality of jet nozzles is defined as the first jet nozzle, and the jet nozzle not located downstream of the obstacle is defined as the second jet nozzle, The plurality of injection nozzles is divided into a plurality of injection nozzle groups including at least one injection nozzle configured to supply the reducing agent from the same reducing agent supply line, and includes the injection nozzle group including the first injection nozzle, namely A first spray nozzle group and a plurality of spray nozzle groups including the second spray nozzle group, which is the spray nozzle group of the second spray nozzle, The operating method of the aforementioned reducing agent supply device includes: The step of 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, and A step of individually adjusting the amount of the reducing agent supplied to the first injection nozzle group and the second injection nozzle group based on the measurement result of the concentration distribution.

According to the method of (6) above, as described in (1) above, the plurality of injection nozzles arranged in a direction crossing the flow direction of the exhaust gas in the flow path of the exhaust gas are classified as including The first injection nozzle group of the first injection nozzle located downstream of the obstacle and the injection nozzle group including the second injection nozzle not located downstream of the obstacle are supplied and restored by the same reducing agent supply line in each injection nozzle group Agent. 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 from the second injection nozzle group. Therefore, even if it is assumed that a drift is generated downstream of the obstacle due to the existence of the obstacle, if the amount of reducing agent supplied to the first injection nozzle group is appropriately adjusted, it is possible to suppress the drift in the injection nozzle due to the drift. The local concentration distribution of the reducing agent in a direction crossing the flow direction of the exhaust gas generated downstream of the cluster is uneven. That is, it is possible to provide an operating method of the reducing agent supply device that can suppress the unevenness of the local concentration distribution of the reducing agent caused by the influence of the drift of the obstacle. Furthermore, as described in (5) above, the concentration distribution of the reducing agent in a direction crossing the flow direction of the exhaust gas measured downstream of the plurality of injection nozzles can be individually adjusted and supplied to the first injection nozzle group and the second injection nozzle group. 2 The amount of reducing agent in the spray nozzle group. Thereby, it is possible to uniformize the concentration distribution of the reducing agent in a direction that intersects the flow direction of the exhaust gas without requiring an individual injection nozzle opening adjustment operation performed by an operator, for example. [Effects of Invention]

According to at least one embodiment of the present invention, it is possible to provide a reducing agent supply device and an operating method of the reducing agent supply device capable of suppressing the unevenness of the local concentration distribution of the reducing agent caused by the influence of the drift of the obstacle .

Several embodiments of the present invention will be described below with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the constituent parts described in the embodiment or shown in the drawings are not intended to limit the scope of the present invention, but are merely illustrative examples. For example, expressions that express relative or absolute arrangements such as "in a certain direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric" or "coaxial", not only strictly It means such a configuration, and it also means a state of relative displacement with a tolerance or an angle or distance that can obtain the same function. Also, for example, expressions that indicate shapes such as quadrangular shapes or cylindrical shapes not only indicate shapes such as quadrangular shapes or cylindrical shapes in a geometrically strict sense, but also include irregularities or inverted portions within the range of obtaining the same effect. Shapes such as corners. On the other hand, the expression of "include", "prepared", "have", "include", or "have" a constituent element is not an exclusive expression that excludes the existence of other constituent elements.

Fig. 1 is a schematic diagram showing the configuration of the downstream side of the exhaust gas flow path of a boiler system to which a reducing agent supply device 10 of at least one embodiment of the present invention is applied. In addition, in the following description, as an example, a case where the denitrification device 1 is arranged in the exhaust gas flow path 2 of a 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 connected to the exhaust gas flow path 2.

As shown in FIG. 1, a denitration device 1 is arranged on the downstream side of the exhaust gas flow path 2 of the boiler system 100. The denitration device 1 is equipped with an SCR catalyst 3 on the downstream side of the exhaust gas flow path 2 that guides the exhaust gas G discharged from the boiler 4, which is arranged in a direction intersecting the flow direction of the exhaust gas G (that is, the exhaust gas flow path The width direction of 2) is extended; and the reducing agent supply device 10 is used to supply the reducing agent 8 (such as anhydrous ammonia, ammonia, urea, urea water, or anhydrous ammonia, ammonia water, urea, or urea water) upstream of the SCR catalyst 3 in the exhaust gas flow path 2. Mixed gas of at least one of these and air, etc.). In addition, in the following description, as an example of the reducing agent 8, it is assumed that ammonia (more specifically, a mixed gas of ammonia and air) is sprayed into the exhaust gas G.

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

The reducing agent supply device 10 is a device for spraying the aforementioned reducing agent 8 into the exhaust gas flow path 2. The reducing agent supply device 10 described in the present invention is configured to inject ammonia in a direction that intersects the flow direction of the exhaust gas G so that the concentration distribution of ammonia becomes uniform.

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 structure of a reducing agent supply device of an embodiment. FIG. 3 is a diagram schematically showing the structure of the reducing agent supply device of an embodiment, and is a partially enlarged view of part III shown in FIG. 2. As illustrated in Figures 2 and 3, the reducing agent supply device 10 of at least one embodiment of the present invention is also called an ammonia injection device or an ammonia injection grid (AIG), and is configured to be internally Ammonia circulates and at least one header 12 extending in the exhaust gas flow path 2 is provided. In addition, the reducing agent supply device 10 is a device 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) where the obstacle 7 is arranged, and is in the flow direction of the exhaust gas G. The downstream of the obstacle 7 is provided with: a plurality of injection nozzles 20, which are arranged at intervals in a direction that intersects the flow direction of the exhaust gas G; and a plurality of reducing agent supply lines 30, which are configured in pairs Each injection nozzle 20 supplies the reducing agent 8.

A plurality of injection nozzles 20 are arranged such that they are respectively arranged on the header 12 on the downstream side of the flow direction of the exhaust gas G with respect to the header 12 and inject the reducing agent 8 toward the downstream. For example, a plurality of spray nozzles 20 may be arranged at equal intervals along the extending direction of the header 12. Moreover, among the plurality of spray nozzles 20, the spray nozzle 20 located downstream of the obstacle 7 is defined as the first spray nozzle 21A, and the spray nozzle 20 not located downstream of the obstacle 7 is defined as the second spray nozzle 22A. In this case, the plurality of injection nozzles 20 are divided into a plurality of injection nozzle groups 24, and the plurality of injection nozzle groups 24 include at least one injection nozzle 20 configured to supply the reducing agent 8 from the same reducing agent supply line 30, and Containing: a first spray nozzle group 21 which is a spray nozzle group 24 including the first spray nozzle 21A and a second spray nozzle group 22 which is a spray nozzle group 24 including a second spray nozzle 22A.

For example, the first injection nozzle group 21 may be arranged in the exhaust gas flow path 2 in a projection of the obstacle 7 located upstream of the first injection nozzle group 21 toward the downstream, and the first header section 12A having a wider width in the above-mentioned one direction. In this case, the second injection nozzle 22A may be arranged in the second header section 12B having a wider width in the above-mentioned one direction than the first header section 12B. Each header section 12A, 12B may include an internal flow path for guiding the reducing agent supplied from the respective reducing agent supply line 30 to the respective injection nozzle 20.

The plurality of reducing agent supply lines 30 can be configured to branch from a main supply line (not shown) and extend in the exhaust gas flow path 2 to supply the reducing agent to the corresponding injection nozzle groups 24.

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 a direction that intersects the flow direction of the exhaust gas G are divided into the following: The first injection nozzle group 21 of the first injection nozzle 21A downstream of the obstacle 7 and the injection nozzle group 24 including the second injection nozzle 22A not located downstream of the obstacle 7 use the same reducing agent in each injection nozzle group 24 The supply line 30 is supplied with the reducing agent 8. 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 and the second injection nozzle group 22 can be adjusted independently. Therefore, even if it is assumed that a drift occurs downstream of the obstacle 7 due to the existence of the obstacle 7, if the amount of the reducing agent 8 supplied to the first injection nozzle group 21 is appropriately adjusted, the drift caused by the aforementioned drift can be suppressed. The local concentration distribution of the reducing agent 8 in a direction crossing the flow direction of the exhaust gas G generated downstream of the injection nozzle group 24 is uneven. That is, it is possible to provide a reducing agent supply device 10 capable of suppressing the unevenness of the local concentration distribution of the reducing agent 8 caused by the influence of the drift of the obstacle 7.

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

According to such a configuration that the number of first injection nozzles 21A included in one first injection nozzle group 21 is less than the number of second injection nozzles 22A included in one second injection nozzle group 22, the flow path of the exhaust gas flow path 2 The ratio of the first jet nozzle group 21 to the cross-sectional area is smaller than that of the second jet nozzle group 22, so it can be more finely suppressed that the ratio of the cross-sectional area of the flow path that cannot be handled by the second jet nozzle group 22 is small. Obstacles 7 (for example, thin pipes, pillars, etc.) have an influence on the concentration distribution of the reducing agent 8 in a local area, so that the concentration distribution can be made uniform.

In any of the above configurations, in several embodiments, for example, as illustrated in FIGS. 2 and 3, the width W of the exhaust gas flow path 2 in a direction intersecting the flow direction of the exhaust gas G, the flow direction The width D of the upper obstacle 7 and the distance L between the obstacle 7 in the flow direction and the first spray nozzle group 21 satisfy the following formula (i) or (ii). L≦2W・・・(i) L≦20D・・・(ii)

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

Here, since the downstream of the obstacle 7 is sufficiently away from the obstacle 7, the influence of the downstream flow of the obstacle 7 is small, and the concentration distribution of the reducing agent 8 in a direction crossing the flow direction of the exhaust gas G is close to uniform, so locally The necessity to distinguish the spray nozzle groups 24 is reduced. On the other hand, by locally distinguishing the spray nozzle group 24 at a position where the distance between the obstacle 7 and the jet nozzle group 24 is close and the influence of the backflow is significant, the unevenness of the local concentration distribution can be effectively reduced. In this regard, as described above, based on the width W of the exhaust gas flow path 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 in the above-mentioned flow direction and the first injection nozzle group 21 The configuration that satisfies the above-mentioned formula (i) or formula (ii), by arranging the first jet nozzle group 21 at a position where the influence of the flow is greater after the obstacle 7 is satisfied, or the relationship of the formula (ii), and The effect described in any of the above embodiments can be enjoyed to the maximum. Furthermore, the distance L in the above formula (i) or (ii) may be the downstream end of the header 12, that is, the base end of the injection nozzle 20 in the flow direction of the exhaust gas G, or The downstream end of the spray nozzle 20 is referred to as the downstream end. In addition, the upstream end of the distance L may use the downstream end of the obstacle 7, or the center of the obstacle 7 (for example, the center of the obstacle 7 in FIG. 3) as the upstream end.

In any of the above-mentioned configurations, in several embodiments, for example, as illustrated in FIG. 3, for example, the pipe axis of the exhaust gas flow path 2 with respect to the flow direction of the exhaust gas G is caused by the obstacle 7. When the angular range of the drift is set to θ, the first injection nozzle group 21 can include the injection nozzles 20 included in the range of D+2Lsinθ with respect to the width W of the exhaust gas flow path 2 as the first injection nozzle 21A . In addition, in some embodiments, for example, the jet nozzle 20 that is arranged offset in the one direction with respect to the projection of the obstacle 7 located upstream of the first jet nozzle group 21 in the flow direction can be defined as the first jet Nozzle 21A. For example, the first injection nozzle 21A may be arranged such that the entirety of the projection of the obstacle 7 toward the downstream of the exhaust gas flow path 2 is overlapped when viewed in the tube axis direction of the exhaust gas flow path 2. In addition, the first injection nozzle 21A may be arranged such that at least a part of the projection of the obstacle 7 is overlapped when viewed in the tube axis direction of the exhaust gas flow path 2. Furthermore, the first injection nozzle 21A may be arranged offset in the width direction of the exhaust gas flow path 2 so as not to overlap the above-mentioned projection. Furthermore, the first spray nozzle group 21 may include a projection of the obstacle 7 located upstream, and spray nozzles located adjacent to the projection in the width direction of the exhaust gas flow path 2 (a direction intersecting the flow direction of the exhaust gas G) 20 includes the first spray nozzle 21A. Alternatively, the first spray nozzle group 21 may include one or more spray nozzles 20 included in a range that can be affected by the downstream flow of the obstacle 7 located upstream as the first spray nozzle 21A.

Here, since the drift caused by the obstacle 7 can be variously changed due to the shape of the obstacle 7, the distance L between the obstacle 7 and the injection nozzle 20, or the flow velocity of the exhaust gas G, there is a flow of the exhaust gas G Only by adjusting the injection amount from the injection nozzle 20 arranged at the strict downstream position of the obstacle 7, the uniformity of the concentration distribution cannot be effectively performed. In this regard, according to the above-mentioned configuration, it is possible to individually adjust the first injection nozzle 21A that includes the projection of the obstacle 7 in the flow direction of the exhaust gas G and is offset in a direction that intersects the flow direction of the exhaust gas G. The supply amount of the reducing agent 8 in the first injection nozzle group 21. Therefore, it is possible to increase the design freedom when determining the injection nozzles 20 of the first injection nozzle group 21 among the plurality of injection nozzles 20 according to various arrangements or designs of the obstacles 7 in the exhaust gas flow path 2.

4 is a side sectional view schematically showing the concentration adjustment of the reducing agent performed by the reducing agent supply device of an embodiment. In any of the above-mentioned configurations, in some embodiments, as illustrated in FIGS. 2 to 4, for example, a plurality of injection nozzles 20 may be discretely arranged over the entire width of the exhaust gas flow path 2. The interval between the spray nozzles 20 and the number of spray nozzles 20 in the width direction of the exhaust gas flow path 2 can be arbitrarily set.

In this way, according to the configuration in which the plurality of injection nozzles 20 are discretely arranged across the entire width of the exhaust gas flow path 2, the concentration distribution of the reducing agent 8 can be uniformized across the entire width of the exhaust gas flow path 2. Therefore, for example, in the case where the reducing agent supply device 10 is arranged upstream of the SCR catalyst 3 installed across the entire width of the exhaust gas flow path 2, the concentration of the reducing agent in the width direction of the exhaust gas flow path 2 can be maximized. The effect of uniform distribution can maximize the denitration performance of the above-mentioned SCR catalyst 3. Furthermore, the plurality of injection nozzles 20 can be differentiated in the width direction of the exhaust gas flow path 2 for each flow velocity region where the flow velocity of the exhaust gas G is different, as illustrated in FIG. 4, for example.

Fig. 5 is a block diagram showing the structure of the control system of the reducing agent supply device of an embodiment. In any of the above-mentioned configurations, in several embodiments, for example, as illustrated in FIG. 2, FIG. 4, and FIG. 5, the reducing agent supply device 10 may further include a concentration sensor 40 that is in the flow direction It is arranged downstream of the plurality of injection nozzle groups 24 for measuring the concentration distribution of the reducing agent 8 in the exhaust gas G in a direction intersecting the flow direction of the exhaust gas G; corresponding to each of the plurality of reducing agent supply lines 30 A plurality of flow regulating valves 32 are provided, and a plurality of valve actuators 34 that can independently change the opening degree of each of the plurality of flow regulating valves 32; and a controller 50, which is based on the detection signal of the concentration sensor 40 , The valve actuator 34 is driven to uniformize the concentration distribution of the reducing agent 8 in a direction crossing the flow direction of the exhaust gas G.

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

The controller 50 is, for example, a computer, except for the CPU 51, a ROM (Read Only Memory) 53 used as a memory for storing various programs or tables and other data executed by the CPU 51, and an expanded area for executing various programs In addition to RAM (Random Access Memory) 52 that functions as a work area such as a computing area, it can also be equipped with a hard disk drive (HDD) as a large-capacity memory device (not shown) for connecting to a communication network Communication interface, and access unit for installing external memory devices, etc. These are all connected via the bus 55. Furthermore, the controller 50 may be connected to, for example, an input unit (not shown) including a keyboard, a mouse, and a touch panel, and a display unit (not shown) including a liquid crystal display device for displaying data.

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

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 can compare the flow of the exhaust gas G with the detection signal from the concentration sensor 40 The feedback control of each valve actuator 34 is performed in a way that the concentration distribution of the reducing agent 8 in one of the directions crossing is uniform. Thereby, it is not necessary, for example, for an operator to perform an opening adjustment operation of the individual flow adjustment valve 32, and the concentration distribution of the reducing agent 8 in a direction crossing the flow direction of the exhaust gas G can be uniformized instantly.

Next, the reducing agent supply method of at least one embodiment of the present invention will be described. Fig. 6 is a flowchart showing the reducing agent supply method of at least one embodiment of the present invention. As illustrated in FIG. 6, the operating method of the reducing agent supply device 10 of at least one embodiment of the present invention is used for the reducing agent supply device 10, which is used for the exhaust gas flow provided with the obstacle 7 The upstream of the SCR catalyst 3 in the circuit 2 supplies the reducing agent 8. The reducing agent supply device 10 of this method is provided with a plurality of injection nozzles 20, which are arranged downstream of the obstacle 7 in the flow direction of the exhaust gas G at intervals along a direction that intersects the flow direction of the exhaust gas G ; And a plurality of reducing agent supply lines 30, which are configured to supply the reducing agent 8 to the plurality of injection nozzles 20. Among the plurality of jet nozzles 20, the jet nozzle 20 located downstream of the obstacle 7 is defined as the first jet nozzle 21A, and the jet nozzle 20 not located downstream of the obstacle 7 is defined as the second jet nozzle 22A, The plurality of injection nozzles 20 are divided into a plurality of injection nozzle groups 24. The plurality of injection nozzle groups 24 include at least one injection nozzle 20 configured to supply the reducing agent 8 from the same reducing agent supply line 30, and including: The spray nozzle group 21 is a spray nozzle group 24 including the first spray nozzle 21A and the second spray nozzle group 22 is a spray nozzle group 24 including the second spray nozzle 22A. Furthermore, the operating method of the reducing agent supply device 10 includes a step of measuring the concentration distribution of the reducing agent 8 or NOx in a direction crossing 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 of individually adjusting the amount of reducing agent 8 supplied to the first injection nozzle group 21 and the second injection nozzle group 22 based on the measurement result of the concentration distribution (step S20).

According to this method, the plurality of injection nozzles 20 arranged in a direction crossing the flow direction of the exhaust gas G in the flow path 2 of the exhaust gas G are classified as including the first injection nozzle located downstream of the obstacle 7 The first injection nozzle group 21 of 21A and the injection nozzle group 24 including the second injection nozzle 22A not located downstream of the obstacle 7 are supplied with the reducing agent 8 to each of the injection nozzle groups 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 and the second injection nozzle group 22 can be adjusted independently. Therefore, even if it is assumed that a drift occurs downstream of the obstacle 7 due to the existence of the obstacle 7, if the amount of the reducing agent 8 supplied to the first injection nozzle group 21 is appropriately adjusted, the drift caused by the aforementioned drift can be suppressed. The local concentration distribution of the reducing agent 8 in a direction crossing the flow direction of the exhaust gas G generated downstream of the injection nozzle group 24 is uneven. Furthermore, the concentration distribution of the reducing agent 8 in a direction intersecting the flow direction of the exhaust gas G measured downstream of the plurality of injection nozzles 20 can be individually adjusted and supplied to the first in such a way that the concentration distribution of the reducing agent 8 is uniformized. The amount of reducing agent 8 in the injection nozzle group 21 and the second injection nozzle group 22. Thereby, it is possible to uniformize the concentration distribution of the reducing agent 8 in a direction crossing the flow direction of the exhaust gas G without the need for an individual injection nozzle 20 opening adjustment operation performed by the operator, for example.

According to at least one embodiment of the present invention described above, it is possible to provide a reducing agent supply device 10 capable of suppressing the unevenness of the local concentration distribution of the reducing agent 8 caused by the influence of the drift of the obstacle 7 and How to use the reducing agent supply device 10.

The present invention is not limited to the above-mentioned embodiment, and includes a form in which a change is made to the above-mentioned embodiment and a form in which these forms are appropriately combined.

1: Denitration device 2: Exhaust gas flow path (flow path) 3: SCR catalyst 5: Stove 6: flue 7: Obstacles 8: reducing agent 10: Reducing agent supply device 12: header 12A: The first header partition 12B: The second header zone 20: Jet nozzle 21: The first jet nozzle group 21A: The first jet nozzle 22: The second jet nozzle group 22A: 2nd jet nozzle 24: Jet nozzle group 30: Reductant supply line 32: Flow adjustment valve 34: Valve actuator 40: Concentration sensor 50: Controller 51: CPU 52: RAM 53: ROM 54: Reductant injection volume adjustment program 55: Bus 100: boiler system D: width G: Exhaust gas S10: steps S20: steps W: width

Fig. 1 is a schematic diagram showing the configuration of the downstream side of the exhaust gas flow path of a boiler system to which a reducing agent supply device according to an embodiment of the present invention is applied. Fig. 2 is a side sectional view schematically showing the structure of a reducing agent supply device of an embodiment. FIG. 3 is a diagram schematically showing the structure of the reducing agent supply device of an embodiment, and is a partially enlarged view of part III shown in FIG. 2. 4 is a side sectional view schematically showing the concentration adjustment of the reducing agent performed by the reducing agent supply device of an embodiment. Fig. 5 is a block diagram showing the structure of the control system of the reducing agent supply device of an embodiment. Fig. 6 is a flowchart showing the reducing agent supply method of at least one embodiment of the present invention.

2: Exhaust gas flow path (flow path)

7: Obstacles

10: Reducing agent supply device

12: header

12A: The first header partition

20: Jet nozzle

21: The first jet nozzle group

21A: The first jet nozzle

22: The second jet nozzle group

22A: 2nd jet nozzle

24: Jet nozzle group

30: Reductant supply line

32: Flow adjustment valve

40: Concentration sensor

50: Controller

G: Exhaust gas

W: width

Claims (6)

A reductant supply device, which is used to supply reductant upstream of the SCR catalyst in the flow path of the exhaust gas with obstacles, and includes: a plurality of injection nozzles, which are in the flow direction of the aforementioned exhaust gas The downstream of the obstacle is arranged at intervals along a direction that intersects the flow direction of the exhaust gas; and a plurality of reducing agent supply lines are configured to supply the reducing agent to the plurality of injection nozzles; and Among the aforementioned plural jet nozzles, the jet nozzle located downstream of the aforementioned obstacle is defined as the first jet nozzle, and the jet nozzle not located downstream of the aforementioned obstacle is defined as the second jet nozzle, the aforementioned plural jets The nozzles are divided into a plurality of injection nozzle groups, and the plurality of injection nozzle groups includes: a first injection nozzle group, which includes a plurality of injection nozzles configured to supply the aforementioned reducing agent from the same first reducing agent supply line A group of injection nozzles, including the aforementioned group of injection nozzles of the first injection nozzle; and a group of second injection nozzles, including a plurality of at least one injection nozzle configured to supply the aforementioned reducing agent from the same second reducing agent supply line And the injection nozzle group of the second injection nozzle; and the injection amount of the reducing agent from the first injection nozzle group via the first reducing agent supply line is the same as that of the reducing agent via the second injection nozzle group. The injection amount of the reducing agent from the second injection nozzle group of the agent supply line can be adjusted independently. The reducing agent supply device of claim 1, wherein the number of the first injection nozzles included in one first injection nozzle group is less than the number of the second injection nozzles included in one second injection nozzle group. The reducing agent supply device of claim 1 or 2, wherein the width W of the flow path in the one direction, the width D of the obstacle in the flow direction, and the obstacle in the flow direction and the first The distance L of the jet nozzle group satisfies the following formula (i) or (ii), L≦2W‧‧‧(i) L≦20D‧‧‧(ii). The reducing agent supply device of claim 1 or 2, wherein the plurality of spray nozzles are discretely arranged across the entire width of the flow path. The reducing agent supply device of claim 1 or 2, further comprising: a concentration sensor, which is arranged downstream of the plurality of injection nozzle groups in the flow direction, and is used to measure the exhaust gas in the one direction Concentration distribution of reducing agent or NOx; a plurality of flow adjustment valves corresponding to each of the aforementioned plurality of reducing agent supply lines, and a plurality of valves that can independently change the opening degree of each of the plurality of flow adjustment valves And a controller, which drives the valve actuator according to the detection signal of the concentration sensor. An operating method of a reducing agent supply device, which is used for a reducing agent supply device, which is used to upstream the SCR catalyst in the flow path of the exhaust gas with obstacles The reducing agent is supplied, and the reducing agent supply device includes: a plurality of injection nozzles, which are located downstream of the obstacle in the flow direction of the exhaust gas, at intervals along a direction that intersects the flow direction of the exhaust gas Configuration; and a plurality of reducing agent supply lines, which are configured to supply the reducing agent to the plurality of injection nozzles; and among the plurality of injection nozzles, the injection nozzle located downstream of the obstacle is defined as the first injection nozzle , When the jet nozzle that is not located downstream of the obstacle is defined as the second jet nozzle, the plurality of jet nozzles are divided into a plurality of jet nozzle groups, and the plurality of jet nozzle groups include: the first jet nozzle group , Which includes a plurality of injection nozzle groups configured to supply at least one injection nozzle of the reducing agent from the same first reducing agent supply line, and the injection nozzle group including the first injection nozzle; and the second injection nozzle The group includes a plurality of injection nozzle groups configured to supply at least one injection nozzle of the reducing agent from the same second reducing agent supply line, and the injection nozzle group including the second injection nozzle; and the reducing agent The operation method of the supply device includes the step of 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, and individually adjusting according to the measurement result of the concentration distribution A step of supplying the amount of the reducing agent to the first injection nozzle group and the second injection nozzle group.

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