JP6016627B2 - Exhaust purification device - Google Patents

Description

  The present invention relates to an exhaust emission control device for an internal combustion engine.

  Conventionally, in order to reduce NOx (nitrogen oxides) contained in exhaust gas from an internal combustion engine, NOx is used by using a catalytic reactor in which a selective reduction type NOx catalyst (SCR catalyst) is arranged and ammonia as a reducing agent. Exhaust gas purification devices that reduce nitrogen to water and nitrogen are known. Ammonia is generated from urea water injected into the high-temperature exhaust gas, and NOx is reduced to nitrogen and water by contacting with the NOx catalyst.

  In such an exhaust purification device, the NOx catalyst of the catalytic reactor is made of an oxide carrier such as Ti formed of a material containing an active component such as V or Cr in a honeycomb structure having a large number of through holes. It is done. By comprising in this way, a contact area increases and a reductive reaction is accelerated | stimulated. On the other hand, when the exhaust gas passes through the through hole, dust contained in the exhaust gas may adhere to the NOx catalyst, block the hole, and reduce the reduction reaction. For this reason, there is one that suppresses the removal of dust attached to the NOx catalyst and the adhesion of dust by injecting pressurized air onto the NOx catalyst. For example, as described in Patent Document 1.

  However, the catalyst reactor (reactor) of the exhaust gas purification device (exhaust denitration device) as described in Patent Document 1 generally injects pressurized air evenly to all NOx catalysts. Therefore, since pressurized air is injected even to the NOx catalyst to which almost no dust is attached, there is a problem in that the amount of dust removal with respect to the amount of air consumption becomes low and efficient dust removal cannot be performed. .

JP-A-8-126817

  The present invention has been made to solve such a problem, and an object of the present invention is to provide an exhaust purification device capable of efficiently removing dust and adhering dust to the NOx catalyst.

  The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

  That is, in the exhaust gas purification apparatus according to claim 1, a soot blower that ejects pressurized air to remove dust adhering to the catalyst is provided in a catalyst reactor in which a plurality of catalysts are arranged in the exhaust flow direction. A soot blower is arranged for each catalyst, and the amount of air injected from the soot blower of the catalyst arranged on the most upstream side is maximized among the amount of air injected from each soot blower within a certain period of time. It is comprised.

  According to a second aspect of the invention, there is provided a differential pressure detection sensor for detecting a differential pressure between the upstream side exhaust pressure and the downstream side exhaust pressure of the catalytic reactor, and when the differential pressure is a predetermined value or more, the one injected from the soot blower It is.

  According to a third aspect of the present invention, the soot blower includes an opening / closing valve, and changes the amount of the injected air according to the number of times the pressurized air is injected from each of the soot blowers.

  According to a fourth aspect of the present invention, the soot blower includes an opening / closing valve, and changes the amount of the injected air according to the injection time of the pressurized air injected from each of the soot blowers.

  According to a fifth aspect of the present invention, the soot blower includes a pressure control valve, and changes the injection air amount by the pressure of the pressurized air injected from each of the soot blowers.

According to a sixth aspect of the present invention, the soot blower includes a plurality of injection nozzles that inject pressurized air , and changes the amount of injection air according to the number of injection nozzles that inject pressurized air .

  As effects of the present invention, the following effects can be obtained.

  According to the first aspect of the present invention, the pressurized air is preferentially injected onto the NOx catalyst at a position where dust is likely to adhere. Thereby, the removal of the dust adhering to the NOx catalyst and the suppression of the adhesion of the dust can be efficiently performed.

  According to the second aspect of the present invention, the injection amount of the pressurized air is changed based on the amount of dust attached to the NOx catalyst. Thereby, the removal of the dust adhering to the NOx catalyst and the suppression of the adhesion of the dust can be efficiently performed.

  According to the invention described in claim 3, by controlling the number of injections, the pressurized air is preferentially injected onto the NOx catalyst at a position where dust is likely to adhere. Thereby, the removal of the dust adhering to the NOx catalyst and the suppression of the adhesion of the dust can be efficiently performed.

  According to the invention described in claim 4, by controlling the injection time, the pressurized air is preferentially injected onto the NOx catalyst at a position where dust is likely to adhere. Thereby, the removal of the dust adhering to the NOx catalyst and the suppression of the adhesion of the dust can be efficiently performed.

  According to the invention described in claim 5, by controlling the injection pressure, the pressurized air is preferentially injected onto the NOx catalyst at a position where dust is likely to adhere. Thereby, the removal of the dust adhering to the NOx catalyst and the suppression of the adhesion of the dust can be efficiently performed.

According to the sixth aspect of the present invention, the pressurized air is preferentially injected onto the NOx catalyst at a position where dust is likely to adhere by changing the number of injection nozzles that inject the pressurized air to be injected. .
Thereby, the removal of the dust adhering to the NOx catalyst and the suppression of the adhesion of the dust can be efficiently performed.

The figure which shows the whole outline | summary in 1st embodiment and 2nd embodiment of the exhaust gas purification device concerning this invention. Schematic which shows the structure of the NOx catalyst and soot blower of the catalytic reactor in 1st embodiment and 2nd embodiment of the exhaust gas purification apparatus which concerns on this invention. (A) The timing chart showing the opening / closing timing and opening time of the air valve for soot blower in the first embodiment of the exhaust purification apparatus according to the present invention (b) The catalyst in the first embodiment of the exhaust purification apparatus according to the present invention The figure which shows the timing chart showing the opening / closing timing and opening time of the air valve for soot blowers when the differential pressure | voltage of a reactor is more than predetermined value. (A) The figure which shows the timing chart showing the opening / closing timing and opening time of the air valve for soot blowers in 2nd embodiment of the exhaust gas purification apparatus which concerns on this invention (b) Catalyst in 2nd embodiment of the exhaust gas purification apparatus which concerns on this invention The figure which shows the timing chart showing the opening / closing timing and opening time of the air valve for soot blowers when the differential pressure | voltage of a reactor is more than predetermined value. The figure which shows the whole outline | summary in 3rd embodiment of the exhaust gas purification apparatus which concerns on this invention. The figure which shows the graph showing the relationship between the pressurized air and the amount of injection air in 3rd embodiment of the exhaust gas purification apparatus which concerns on this invention. Schematic which shows the structure of the NOx catalyst and soot blower of the catalytic reactor in 4th embodiment of the exhaust gas purification apparatus which concerns on this invention.

  Hereinafter, an exhaust purification device 1 that is a first embodiment of the exhaust purification device according to the present invention will be described with reference to FIGS. 1 and 2. In this embodiment, “upstream side” indicates the upstream side in the fluid flow direction, and “downstream side” indicates the downstream side in the fluid flow direction. The exhaust device is not limited to the present embodiment, and may be an airless system that does not use pressurized air.

  As shown in FIG. 1, the exhaust gas purification apparatus 1 purifies exhaust gas discharged from an engine 22 that is an internal combustion engine that drives a generator 24. The exhaust purification device 1 is provided in the exhaust pipe 23 of the engine 22. The exhaust purification device 1 includes a urea water injection nozzle 2, a urea supply channel 3, a first air supply channel 4, a pressurized air supply pump (compressor) 5, an air tank 6, a urea air valve 8, and a urea water supply pump 9. , A switching valve 11, a catalyst reactor 12, a soot blower group 17, a soot blower air valve group 18, a second air supply passage 19, a differential pressure sensor 20, a control device 21, and the like. The exhaust purification device 1 may purify exhaust exhausted from a so-called main machine that drives a propeller or the like.

  The urea water injection nozzle 2 supplies urea water into the exhaust pipe 23. The urea water injection nozzle 2 is composed of a tubular member, and is provided so that one side (downstream side) of the urea water injection nozzle 2 is inserted from the outside to the inside of the catalyst reactor 12 or the exhaust pipe 23. The urea water injection nozzle 2 is disposed on the upstream side of the first NOx catalyst 14 of the catalytic reactor 12 described later. A urea supply flow path 3 that is a flow path of urea water is connected to the urea water injection nozzle 2. The urea water injection nozzle 2 is connected to a first air supply channel 4 that is a channel for pressurized air.

  The pressurized air supply pump (compressor) 5 supplies pressurized air. The pressurized air supply pump 5 supplies air after being pressurized (compressed). The pressurized air supply pump 5 supplies air to the air tank 6 (reservoir tank 7) when the pressure of the air tank 6 (reservoir tank 7) falls below a predetermined pressure, and the pressure of the air tank 6 (reservoir tank 7) is predetermined. Stops when the pressure is reached. Note that the pressurized air supply pump 5 is not particularly limited in the present embodiment, and may be any pump that can maintain the pressure of the air tank 6 (reservoir tank 7).

  The urea air valve 8 communicates or blocks the flow path of the pressurized air. The urea air valve 8 is provided in the first air supply flow path 4. The urea air valve 8 is configured by an electromagnetic valve, and is configured to be able to block or communicate with the first air supply flow path 4 by sliding a spool (not shown). That is, the urea air valve 8 brings the first air supply passage 4 into a communicating state, so that pressurized air is supplied to the urea water injection nozzle 2. The urea air valve 8 is not limited to this embodiment.

  The urea water supply pump 9 supplies urea water. The urea water supply pump 9 is provided in the urea supply flow path 3. The urea water supply pump 9 supplies urea water in the urea water tank 10 to the urea water injection nozzle 2 through the urea supply flow path 3 at a predetermined flow rate. The urea water supply pump 9 is not limited to this embodiment.

  The switching valve 11 switches the flow path of urea water. The switching valve 11 is provided on the downstream side of the urea water supply pump 9 in the urea supply flow path 3. The switching valve 11 is composed of an electromagnetic valve, and is configured to be able to block or communicate with the urea supply flow path 3 by sliding a spool (not shown). That is, the urea water is supplied to the urea water injection nozzle 2 when the switching valve 11 brings the urea supply flow path 3 into a communicating state. The switching valve 11 is not limited to this embodiment.

  The catalytic reactor 12 selectively reduces NOx in the exhaust gas by a NOx catalyst arranged inside. The catalytic reactor 12 includes a housing 13, a first NOx catalyst 14, a second NOx catalyst 15, and a third NOx catalyst 16.

  An exhaust pipe 23 connected to the engine 22 is connected to one end of the housing 13. An exhaust pipe 23 that is open to the outside is connected to the other end of the housing 13. That is, the housing 13 is configured as an exhaust passage through which exhaust from the engine 22 flows from one side to the other side. A first NOx catalyst 14, a second NOx catalyst 15, and a third NOx catalyst 16 are arranged in the housing 13 in order from one side (upstream side of exhaust) at a predetermined interval. The housing 13 is configured so that the first NOx catalyst 14, the second NOx catalyst 15, and the third NOx catalyst 16 can be sealed and detachable therein. In addition, the number of NOx catalysts arrange | positioned inside the housing | casing 13 is not limited to this embodiment.

  The first NOx catalyst 14, the second NOx catalyst 15, and the third NOx catalyst 16 are formed of a material containing a metal such as alumina, zirconia, vanadia / titania, or zeolite. The 1st NOx catalyst 14, the 2nd NOx catalyst 15, and the 3rd NOx catalyst 16 are comprised from the substantially rectangular parallelepiped which has the honeycomb structure in which many through-holes were formed (refer FIG. 2). The first NOx catalyst 14, the second NOx catalyst 15, and the third NOx catalyst 16 are disposed inside the casing 13 of the catalytic reactor 12 so that the axial direction of the through hole coincides with the flow direction of the exhaust gas. Therefore, in the catalytic reactor 12, the exhaust gas supplied from one side of the housing 13 passes through the through holes of the NOx catalysts in the order of the first NOx catalyst 14, the second NOx catalyst 15, and the third NOx catalyst 16. It is configured to be discharged from the other side.

The soot blower group 17 injects pressurized air to the first NOx catalyst 14, the second NOx catalyst 15, and the third NOx catalyst 16. The soot blower group 17 includes a first soot blower 17a, a second soot blower 17b, and a third soot blower 17c. The first soot blower 17a, the second soot blower 17b, and the third soot blower 17c are configured such that a plurality of injection nozzles 17d are disposed in the middle of the tubular member and communicate with the inside of the tubular member.
Each soot blower is provided in the catalyst reactor 12 so that one side (downstream side) thereof is inserted from the outside of the catalyst reactor 12 into the housing 13. Each soot blower is connected to the reservoir tank 7 via a second air supply channel 19 whose other side (upstream side) is a channel for pressurized air. The reservoir tank 7 is connected to an air tank 6 disposed at a separated position.

  As shown in FIGS. 1 and 2, the first soot blower 17 a is arranged on the upstream side of the first NOx catalyst 14 so that the injection port of the injection nozzle 17 d faces the first NOx catalyst 14. Similarly, the second soot blower 17 b is disposed downstream of the first NOx catalyst 14 and upstream of the second NOx catalyst 15. The third soot blower 17 c is disposed on the downstream side of the second NOx catalyst 15 and on the upstream side of the third NOx catalyst 16. Each soot blower injection nozzle 17d is arranged so that pressurized air is injected over the entire exhaust passage surface of the NOx catalyst facing each other. The first soot blower 17a is configured to be able to inject pressurized air over the entire exhaust passage surface of the first NOx catalyst 14. The second soot blower 17b is configured to be able to inject pressurized air over the entire exhaust passage surface of the second NOx catalyst 15. The third soot blower 17c is configured to be able to inject pressurized air over the entire exhaust passage surface of the third NOx catalyst 16.

  The soot blower air valve group 18 communicates or blocks the flow path of the pressurized air. The soot blower air valve group 18 includes a first soot blower air valve 18a, a second soot blower air valve 18b, and a third soot blower air valve 18c. The first soot blower air valve 18a is provided in the second air supply channel 19 connected to the first soot blower 17a. The second soot blower air valve 18b is provided in the second air supply passage 19 connected to the second soot blower 17b. The third soot blower air valve 18c is provided in the second air supply passage 19 connected to the third soot blower 17c.

  The first soot blower air valve 18a, the second soot blower air valve 18b, and the third soot blower air valve 18c are constituted by electromagnetic valves, and the second air supply passage 19 is cut off by sliding a spool (not shown). It is configured to be able to communicate. In other words, the first soot blower air valve 18a brings the second air supply passage 19 into communication so that pressurized air is supplied to the first soot blower 17a. The second soot blower air valve 18b brings the second air supply passage 19 into a communicating state, whereby pressurized air is supplied to the second soot blower 17b. The third soot blower air valve 18c brings the second air supply channel 19 into communication, whereby pressurized air is supplied to the third soot blower 17c. Each soot blower air valve is not limited to this embodiment.

  The differential pressure sensor 20 detects a differential pressure ΔP between the upstream exhaust pressure and the downstream exhaust pressure of the catalyst reactor 12. The differential pressure sensor 20 includes an upstream pressure sensor 20a and a downstream pressure sensor 20b. The upstream pressure sensor 20 a is disposed on the upstream side of the first NOx catalyst 14 of the catalytic reactor 12, and the downstream pressure sensor 20 b is disposed on the downstream side of the third NOx catalyst 16 of the catalytic reactor 12. With this configuration, it is possible to detect whether or not the through hole of each NOx catalyst is blocked and the degree thereof from the value of the differential pressure ΔP.

  The control device 21 controls the urea water supply pump 9, the switching valve 11, the urea air valve 8, the soot blower air valve group 18, and the like. The control device 21 stores various programs and data for controlling the urea water supply pump 9, the switching valve 11, the urea air valve 8, the soot blower air valve group 18, and the like. The control device 21 may be configured such that a CPU, a ROM, a RAM, an HDD, and the like are connected by a bus, or may be configured by a one-chip LSI or the like. The control device 21 can also be configured integrally with an ECU 25 that controls the engine 22.

  The control device 21 is connected to the solenoid of the urea air valve 8 and can control the opening and closing of the urea air valve 8.

  The control device 21 is connected to the drive motor of the urea water supply pump 9 and can control the operation state of the urea water supply pump 9. That is, the control device 21 can arbitrarily change the amount of urea water added to the exhaust gas by controlling the operation state of the urea water supply pump 9.

  The control device 21 is connected to the solenoid of the switching valve 11 and can control opening and closing of the switching valve 11.

  The control device 21 is connected to the solenoid of the urea air valve 8 and can control the opening and closing of the urea air valve 8.

  The control device 21 is connected to each solenoid of the first soot blower air valve 18a, the second soot blower air valve 18b, and the third soot blower air valve 18c, and the first soot blower air valve 18a, the second soot blower air valve 18b. It is possible to control the opening / closing of the third soot blower air valve 18c.

  The control device 21 is connected to the differential pressure sensor 20 and can acquire a signal regarding the differential pressure ΔP between the upstream exhaust pressure and the downstream exhaust pressure of the catalytic reactor 12 detected by the differential pressure sensor 20. .

  The control device 21 is connected to the ECU 25 and can acquire various types of information related to the engine 22 that the ECU 25 acquires. Moreover, the control apparatus 21 may acquire each information regarding the engine 22 directly not via ECU25.

  The control device 21 is connected to an input device (not shown), and can acquire a signal regarding the target purification rate and urea water concentration input from the input device. Alternatively, it is possible to input and define the target purification rate and the concentration of urea water in advance.

  Hereinafter, the control mode of the soot blower group 17 (the soot blower air valve group 18) in the exhaust purification apparatus 1 which is the first embodiment of the exhaust purification apparatus according to the present invention will be described with reference to FIG. The first, second, and third descriptions in FIGS. 3 and 4 represent the first soot blower air valve 18a, the second soot blower air valve 18b, and the third soot blower air valve 18c, respectively.

  As shown in FIG. 3, the control device 21 controls the first soot blower air valve 18a, the second soot blower air valve 18b, and the third soot blower air valve 18c (see FIG. 2) for a predetermined injection time T1 (for example, 0. Open the valve only for 3 seconds. Thus, the first soot blower 17a, the second soot blower 17b, and the third soot blower 17c are injected from the respective injection nozzles 17d to the first NOx catalyst 14, the second NOx catalyst 15, and the third NOx catalyst 16 that are opposed to each other ( Hereinafter, it is simply referred to as “soot blow”). The control device 21 soot blows each NOx catalyst again by each soot blower after a predetermined time T2 (for example, 15 minutes) has elapsed.

  Specifically, as shown in FIG. 3A, the control device 21 performs soot blow to the first NOx catalyst 14 by the first soot blower 17a. Next, the control device 21 performs soot blow to the second NOx catalyst 15 by the second soot blower 17b after a predetermined time T2. Next, the control device 21 performs soot blow to the first NOx catalyst 14 by the first soot blower 17a after a predetermined time T2. Next, the control device 21 performs the soot blow to the third NOx catalyst 16 by the third soot blower 17c after a predetermined time T2. Then, the control device 21 again performs soot blow to the first NOx catalyst 14 by the first soot blower 17a.

  That is, the control device 21 performs soot blowing in the order of the first soot blower 17a, the second soot blower 17b, the first soot blower 17a, the third soot blower 17c, the first soot blower 17a,. As a result, the number of times of soot blow by the first soot blower 17a (open time of the first soot blower air valve 18a) is maximized within the fixed period T3. That is, the control device 21 sets the soot blower air valve group so that the amount of pressurized air injected from the first soot blower 17a of the first NOx catalyst 14 arranged on the most upstream side of the catalyst reactor 12 is maximized. 18 is controlled.

  As shown in FIG. 3B, when the differential pressure ΔP detected by the differential pressure sensor 20 (see FIG. 1) is equal to or greater than a predetermined value Pt, the control device 21 shortens the predetermined time T2 to reduce the predetermined time T2s (for example, 10 minutes). That is, the control device 21 shortens the interval of soot blow because there is a possibility that some of the through holes of the first NOx catalyst 14, the second NOx catalyst 15, and the third NOx catalyst 16 are blocked. As a result, the number of soot blows by the soot blower group 17 increases within a certain period T3. That is, the control device 21 controls the soot blower air valve group 18 so that the amount of pressurized air injected from the soot blower group 17 increases. In addition, the control aspect which increases the injection air quantity of pressurized air is not limited to this embodiment, You may shorten only the space | interval of the soot blow performed with respect to the 1st NOx catalyst 14. FIG.

  When the differential pressure ΔP detected by the differential pressure sensor 20 becomes equal to or less than the predetermined value Pt, the control device 21 extends the predetermined time T2s to the predetermined time T2, as shown in FIG. That is, the control device 21 returns the interval for performing the soot blow to the normal state on the assumption that the blocking of the through holes of the first NOx catalyst 14, the second NOx catalyst 15, and the third NOx catalyst 16 has been eliminated, and reduces the injection air amount of the pressurized air. Suppress.

  As described above, the exhaust gas purification apparatus 1 according to the present invention includes a catalyst reactor 12 in which the first NOx catalyst 14, the second NOx catalyst 15, and the third NOx catalyst 16 that are a plurality of catalysts are arranged side by side in the exhaust flow direction. In an exhaust emission control device 1 provided with a first soot blower 17a, a second soot blower 17b, and a third soot blower 17c for ejecting pressurized air to remove dust adhering to the first NOx catalyst 14, the second NOx catalyst 15 and the third NOx catalyst 16. A soot blower is arranged for each catalyst, and the first NOx catalyst arranged on the most upstream side among the injected air amounts injected from the first soot blower 17a, the second soot blower 17b, and the third soot blower 17c within a certain period of time 14 is configured so that the amount of air injected from the first soot blower 17a is maximized. That. By comprising in this way, pressurized air is mainly injected by the 1st NOx catalyst 14 of the position where dust tends to adhere. Thereby, the removal of the dust adhering to the 1st NOx catalyst 14, the 2nd NOx catalyst 15, and the 3rd NOx catalyst 16 and the suppression of the adhesion of the dust can be performed efficiently.

  Further, a differential pressure sensor 20 that detects a differential pressure ΔP between the upstream side exhaust pressure and the downstream side exhaust pressure of the catalyst reactor 12 is provided. When the differential pressure ΔP is equal to or greater than a predetermined value Pt, the first soot blower 17a and the second soot blower are provided. 17b and the third soot blower 17c increase the amount of the injected air. With this configuration, the injection amount of the pressurized air is changed based on the amount of soot adhering to the first NOx catalyst 14, the second NOx catalyst 15, and the third NOx catalyst 16. Thereby, the removal of the dust adhering to the 1st NOx catalyst 14, the 2nd NOx catalyst 15, and the 3rd NOx catalyst 16 and the suppression of the adhesion of the dust can be performed efficiently.

  The first soot blower 17a, the second soot blower 17b, and the third soot blower 17c include a first soot blower air valve 18a, a second soot blower air valve 18b, and a third soot blower air valve 18c, which are on-off valves. The injection air amount is changed according to the number of injections of pressurized air injected from the soot blower 17a, the second soot blower 17b, and the third soot blower 17c. With this configuration, the pressurized air is preferentially injected onto the first NOx catalyst 14 at a position where dust is likely to adhere by controlling the number of injections. Thereby, the removal of the dust adhering to the 1st NOx catalyst 14, the 2nd NOx catalyst 15, and the 3rd NOx catalyst 16 and the suppression of the adhesion of the dust can be performed efficiently.

  Next, an exhaust purification device 1 that is a second embodiment of the exhaust purification device according to the present invention will be described with reference to FIGS. 1, 2, and 4. In the following embodiments, the same points as those of the above-described embodiments will not be specifically described, and different portions will be mainly described.

  As shown in FIGS. 1, 2, and 4 (b), in the control of the soot blower group 17 (the soot blower air valve group 18) in the exhaust purification device 1, the control device 21 detects the differential pressure detected by the differential pressure sensor 20. When ΔP is equal to or greater than the predetermined value Pt, the injection time T1 is extended to an injection time T1e (for example, 0.7 seconds) (see FIG. 4B). That is, the control device 21 lengthens the time for soot blowing because there is a possibility that some of the through holes of the first NOx catalyst 14, the second NOx catalyst 15, and the third NOx catalyst 16 are blocked. As a result, the soot blow time by the soot blower group 17 increases within a certain period T3. That is, the control device 21 controls the soot blower air valve group 18 so that the amount of pressurized air injected from the soot blower group 17 increases. In addition, the control aspect which increases the injection air quantity of pressurized air is not limited to this embodiment, You may lengthen only the time of the soot blow performed with respect to the 1st NOx catalyst 14. FIG.

  As shown in FIG. 4A, when the differential pressure ΔP detected by the differential pressure sensor 20 becomes equal to or less than a predetermined value Pt, the control device 21 shortens the injection time T1e to the injection time T1. In other words, the control device 21 returns the time for soot blow to the normal state and the injection air amount of the pressurized air is reduced, assuming that the blocking of the through holes of the first NOx catalyst 14, the second NOx catalyst 15 and the third NOx catalyst 16 has been resolved. Suppress.

  As described above, in the exhaust purification device 1 according to the present invention, the first soot blower 17a, the second soot blower 17b, and the third soot blower 17c are the first soot blower air valve 18a, the second soot blower air valve 18b, and the on / off valves. A third soot blower air valve 18c is provided, and the injection air amount is changed according to the injection time of the pressurized air injected from each of the soot blowers. With this configuration, the pressurized air is preferentially injected onto the first NOx catalyst 14 at a position where dust is likely to adhere by controlling the injection time. Thereby, the removal of the dust adhering to the 1st NOx catalyst 14, the 2nd NOx catalyst 15, and the 3rd NOx catalyst 16 and the suppression of the adhesion of the dust can be performed efficiently.

  Next, an exhaust purification device 1 that is a third embodiment of the exhaust purification device according to the present invention will be described with reference to FIG. 3 (a), FIG. 5 and FIG.

  As shown in FIG. 5, the exhaust purification device 1 includes a urea water injection nozzle 2, a urea supply channel 3, a first air supply channel 4, a pressurized air supply pump (compressor) 5, a urea air valve 8, urea Water supply pump 9, switching valve 11, catalyst reactor 12, soot blower group 17, second air supply flow path 19, soot blower air valve group 18, differential pressure sensor 20 and control device 21, pressure control valve group 26, etc. It has.

  The pressure control valve group 26 changes the pressure of the pressurized air. The pressure control valve group 26 includes a first pressure control valve 26a, a second pressure control valve 26b, and a third pressure control valve 26c. The first pressure control valve 26a is provided in the second air supply channel 19 upstream of the first soot blower air valve 18a. The second pressure control valve 26b is provided in the second air supply channel 19 upstream of the second soot blower air valve 18b. The third pressure control valve 26c is provided in the second air supply channel 19 upstream of the third soot blower air valve 18c.

  The 1st pressure control valve 26a, the 2nd pressure control valve 26b, and the 3rd pressure control valve 26c are constituted by an electromagnetic proportional valve, and are constituted so that change of the pressure of the pressurized air discharged from the pressure control valve concerned is possible. That is, the pressure of the pressurized air supplied to the first soot blower 17a is changed by the first pressure control valve 26a. The pressure of the pressurized air supplied to the second soot blower 17b is changed by the second pressure control valve 26b. The pressure of the pressurized air supplied to the third soot blower 17c is changed by the third pressure control valve 26c. Each pressure control valve is not limited to the present embodiment.

  The control device 21 is connected to solenoids of the first pressure control valve 26a, the second pressure control valve 26b, and the third pressure control valve 26c, and the first pressure control valve 26a, the second pressure control valve 26b, and the third pressure control valve. It is possible to control the opening degree of 26c.

  Hereinafter, the control mode of the soot blower group 17 (the soot blower air valve group 18) in the exhaust purification apparatus 1 which is the third embodiment of the exhaust purification apparatus according to the present invention with reference to FIG. 3 (a), FIG. 5 and FIG. Will be described.

  As shown in FIG. 3A and FIG. 5, the control device 21 controls the first pressure control valve 26a, the second pressure control valve 26b, and the third pressure control valve 26c to a predetermined air pressure P1 (for example, 0.5 MPa). The soot blow is performed on each NOx catalyst by the first soot blower 17a, the second soot blower 17b, and the third soot blower 17c. As a result, in the first soot blower 17a, the second soot blower 17b, and the third soot blower 17c, pressurized air is injected from the respective injection nozzles 17d to each NOx catalyst at a pressure of 0.5 MPa.

  As shown in FIG. 6, when the differential pressure ΔP detected by the differential pressure sensor 20 is equal to or greater than a predetermined value Pt, the control device 21 increases the predetermined air pressure P1 to a predetermined air pressure P1h (for example, 0.7 MPa). To. That is, the control device 21 increases the pressure of the pressurized air that performs the soot blow because there is a possibility that some of the through holes of the first NOx catalyst 14, the second NOx catalyst 15, and the third NOx catalyst 16 are blocked. That is, the control device 21 controls the pressure control valve group 26 so that the injection air amount of the pressurized air injected from the soot blower group 17 increases within the fixed period T3. In addition, the control aspect which increases the injection air quantity of pressurized air is not limited to this embodiment, You may make only the pressure of the soot blow performed with respect to the 1st NOx catalyst 14 high.

  When the differential pressure ΔP detected by the differential pressure sensor 20 becomes equal to or less than the predetermined value Pt, the control device 21 reduces the predetermined air pressure P1h to the predetermined air pressure P1. That is, the control device 21 reduces the pressure of the pressurized air that performs the soot blow, assuming that the blocking of the through holes of the first NOx catalyst 14, the second NOx catalyst 15, and the third NOx catalyst 16 has been eliminated, Suppress.

  As described above, in the exhaust purification device 1 according to the present invention, the first soot blower 17a, the second soot blower 17b, and the third soot blower 17c are the first pressure control valve 26a, the second pressure control valve 26b, and the second soot blower. A three-pressure control valve 26c is provided, and the injection air amount is changed by the pressure of pressurized air injected from the first soot blower 17a, the second soot blower 17b, and the third soot blower 17c. With this configuration, the pressurized air is preferentially injected onto the first NOx catalyst 14 at a position where dust is likely to adhere by controlling the injection pressure. Thereby, the removal of the dust adhering to the 1st NOx catalyst 14, the 2nd NOx catalyst 15, and the 3rd NOx catalyst 16 and the suppression of the adhesion of the dust can be performed efficiently.

  Next, an exhaust emission control device 1 that is a fourth embodiment of the exhaust emission control device according to the present invention will be described with reference to FIG.

  As shown in FIG. 7, the first soot blower 17a, the second soot blower 17b, and the third soot blower 17c are provided with an additional injection nozzle 17e. Specifically, the additional injection nozzle 17e of the first soot blower 17a can inject the pressurized air intensively on the portion of the exhaust passage surface of the first NOx catalyst 14 where the through holes to which dust is likely to adhere gather. Composed. The additional injection nozzle 17e of the second soot blower 17b is configured to be able to inject pressurized air intensively at a portion of the exhaust passage surface of the second NOx catalyst 15 where through holes to which soot easily adheres gather. The additional injection nozzle 17e of the third soot blower 17c is configured to be capable of injecting pressurized air intensively at a portion of the exhaust passage surface of the third NOx catalyst 16 where through holes to which dust is likely to adhere gather.

  The soot blower air valve group 18 communicates or blocks the flow path of the pressurized air. The soot blower air valve group 18 includes a first soot blower air valve 18a, a first additional injection nozzle air valve 18d, a second soot blower air valve 18b, a second additional injection nozzle air valve 18e, and a third soot blower air valve. 18c and the third additional injection nozzle air valve 18f. The first additional injection nozzle air valve 18d is provided in the second air supply flow path 19 connected to the additional injection nozzle 17e of the first soot blower 17a. The second additional injection nozzle air valve 18e is provided in the second air supply flow path 19 connected to the additional injection nozzle 17e of the second soot blower 17b. The third additional injection nozzle air valve 18f is provided in the second air supply flow path 19 connected to the additional injection nozzle 17e of the third soot blower 17c.

  The first additional injection nozzle air valve 18d, the second additional injection nozzle air valve 18e, and the third additional injection nozzle air valve 18f are composed of electromagnetic valves, and are supplied with the second air by sliding a spool (not shown). The flow path 19 is configured to be blocked or communicated. That is, the first additional injection nozzle air valve 18d, the second additional injection nozzle air valve 18e, and the third additional injection nozzle air valve 18f bring the second air supply flow path 19 into a communication state, whereby the additional injection nozzle 17e. Is supplied with pressurized air. Each additional injection nozzle air valve is not limited to this embodiment.

  The control device 21 is connected to solenoids of the first additional injection nozzle air valve 18d, the second additional injection nozzle air valve 18e, and the third additional injection nozzle air valve 18f, and the first additional injection nozzle air valve 18d, It is possible to control the opening and closing of the second additional injection nozzle air valve 18e and the third additional injection nozzle air valve 18f.

  Below, the control aspect of the soot blower group 17 (the soot blower air valve group 18) in the exhaust purification apparatus 1 which is 4th embodiment of the exhaust purification apparatus which concerns on this invention is demonstrated.

  When the differential pressure ΔP detected by the differential pressure sensor 20 is equal to or greater than the predetermined value Pt, the control device 21 controls the opening / closing of the first additional air nozzle 18d for the injection nozzle in accordance with the first soot blower air valve 18a. Similarly, the control device 21 controls the opening and closing of the second additional injection nozzle air valve 18e in accordance with the second soot blower air valve 18b. The control device 21 controls the opening and closing of the third additional injection nozzle air valve 18f in accordance with the third soot blower air valve 18c. That is, the control device 21 injects pressurized air from each additional injection nozzle 17e on the assumption that some of the through holes of the first NOx catalyst 14, the second NOx catalyst 15, and the third NOx catalyst 16 may be blocked. To control. As a result, the control device 21 controls the soot blower air valve group 18 so that the amount of pressurized air injected from the soot blower group 17 increases within a certain period T3. In addition, the control aspect which increases the injection air quantity of pressurized air is not limited to this embodiment, You may control only opening / closing of the air valve 18d for 1st additional injection nozzles.

  When the differential pressure ΔP detected by the differential pressure sensor 20 becomes equal to or less than the predetermined value Pt, the control device 21 detects the first additional injection nozzle air valve 18d, the second additional injection nozzle air valve 18e, and the third additional injection nozzle. The air valve 18f is closed. That is, the control device 21 determines that the blocking of the through holes of the first NOx catalyst 14, the second NOx catalyst 15, and the third NOx catalyst 16 has been eliminated, the first additional injection nozzle 17 e, the second additional injection nozzle 17 e, and the third additional injection nozzle. The soot blow from 17e is stopped and the injection air quantity of pressurized air is suppressed.

As described above, in the exhaust purification device 1 according to the present invention, the first soot blower 17a, the second soot blower 17b, and the third soot blower 17c are provided with the plurality of injection nozzles 17d and 17e for injecting the pressurized air. The amount of spray air is changed according to the number of spray nozzles 17d and 17e to be sprayed. By configuring in this way, the pressurized air is preferentially injected to the first NOx catalyst 14 at a position where dust is likely to adhere by changing the number of injection nozzles that inject the pressurized air. Thereby, the removal of the dust adhering to the 1st NOx catalyst 14, the 2nd NOx catalyst 15, and the 3rd NOx catalyst 16 and the suppression of the adhesion of the dust can be performed efficiently.

  Further, in order to efficiently suppress the dust in the exhaust from adhering to the first NOx catalyst 14, the second NOx catalyst 15, and the third NOx catalyst 16, the control modes from the first embodiment to the fourth embodiment are appropriately combined. It is also possible to implement.

DESCRIPTION OF SYMBOLS 1 Exhaust purification device 12 Catalytic reactor 14 1st NOx catalyst 15 2nd NOx catalyst 16 3rd NOx catalyst 17a 1st soot blower 17b 2nd soot blower 17c 3rd soot blower

Claims (6)

In the exhaust gas purification apparatus provided with a soot blower that removes soot and dust adhering to the catalyst by ejecting pressurized air to a catalyst reactor in which a plurality of catalysts are arranged in the exhaust flow direction,
A soot blower is arranged for each catalyst so that the amount of air injected from the soot blower of the catalyst arranged upstream is maximized among the amount of air injected from each soot blower within a certain period of time. Exhaust purification device configured.   A differential pressure detection sensor that detects a differential pressure between the upstream exhaust pressure and the downstream exhaust pressure of the catalyst reactor is provided, and when the differential pressure is equal to or greater than a predetermined value, the injection air amount injected from the soot blower is increased. The exhaust emission control device according to claim 1.   The exhaust purification device according to claim 1 or 2, wherein the soot blower includes an on-off valve, and changes the amount of injected air according to the number of times of pressurized air injected from each of the soot blowers.   The exhaust purification device according to any one of claims 1 to 3, wherein the soot blower includes an on-off valve, and changes the amount of injected air according to an injection time of pressurized air injected from each of the soot blowers.   The exhaust purification device according to any one of claims 1 to 4, wherein the soot blower includes a pressure control valve, and changes the amount of the injected air according to a pressure of pressurized air injected from each of the soot blowers. The said soot blower is provided with the some injection nozzle which injects pressurized air , and changes the said injection air quantity with the number of the injection nozzles which inject | pour pressurized air. Exhaust purification equipment.

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