JP6232257B2 - Exhaust gas purification system and ship equipped with the same - Google Patents

Description

  The present invention relates to an exhaust gas purification system that removes harmful components in exhaust gas discharged from an engine mounted on a ship, and a ship equipped with the same.

  Conventionally, in a ship such as a tanker or a transport ship, the amount of electric power consumed by various auxiliary machines, cargo handling devices, lighting, air conditioning and other equipment is enormous. In order to supply electric power to these electric systems, diesel A diesel generator is provided that combines an engine and a generator that generates electricity by driving the diesel engine (see, for example, Patent Document 1). Diesel engines are known to be one of the most energy efficient types of internal combustion engines, and the amount of carbon dioxide contained in exhaust gas per unit output is small. In addition, since a low-quality fuel such as heavy oil can be used, there is an advantage that it is economically excellent.

  Diesel engine exhaust gas contains a large amount of nitrogen oxides, sulfur oxides, particulate matter and the like in addition to carbon dioxide. These are mainly derived from heavy oil, which is a fuel, and are harmful substances that hinder environmental conservation. In particular, nitrogen oxides (hereinafter referred to as NOx) are harmful to human bodies and exhibit strong acidity, and are also considered to cause acid rain. Accordingly, it is understood that a machine that drives a diesel generator, such as a ship, has a very large amount of NOx emission and a large burden on the global environment.

  A selective catalytic reduction method (hereinafter referred to as an SCR method) using urea as a reducing agent has been generalized as a post-treatment means for greatly purifying NOx. In general, the SCR method uses a NOx catalyst having a honeycomb structure made of a material in which an active component such as V or Cr is supported on an oxide carrier such as Ti. When urea water as a reducing agent aqueous solution is sprayed on the upstream side of the NOx catalyst, the urea water is hydrolyzed by the heat of the exhaust gas to generate ammonia, which acts on NOx as a reducing agent, and converts NOx into harmless nitrogen. Decomposes into water.

JP 2006-341742 A

  In consideration of the global environment, it is necessary to remove NOx in the exhaust gas as much as possible, and it is preferable to regulate it uniformly regardless of the high seas territorial waters. As a result of this, a regulatory sea area will be established for NOx. As described above, since the NOx catalyst has a honeycomb structure, it may be clogged with soot and fine particles in the exhaust gas. Further, the performance of the NOx catalyst is degraded by sulfur components in the exhaust gas and products derived therefrom. In order to extend the life of the NOx catalyst as much as possible to reduce running costs and ensure compliance with regulations in the regulated sea area, it is necessary not to expose the NOx catalyst to exhaust gas during navigation outside the regulated sea area. Conceivable.

  Therefore, the applicant of the present application has previously provided a purification casing that accommodates the NOx catalyst in the exhaust path of the engine, and bypasses the exhaust gas from the upstream side of the purification casing in the exhaust path without bypassing the NOx catalyst. Has been proposed (see, for example, JP 2010-71149 A). In this case, exhaust gas is sent to the purification casing side during navigation in the restricted sea area, and exhaust gas is sent to the bypass path side during navigation outside the restricted sea area. For this reason, it becomes possible to extend the life of the NOx catalyst, and there is an advantage that the running cost can be reduced and the purification performance can be maintained for a long time.

  However, in the conventional configuration, since the bypass path that bypasses the NOx catalyst is provided separately from the exhaust path and the purification casing, there is a problem that the piping distance of the bypass path must be increased, and the manufacturing cost increases. In addition, since it is necessary to secure an installation space for the bypass path separately from the purification casing, for example, when the engine room of a ship or the like is narrow, it may be difficult to install the bypass path.

  An object of the present invention is to provide an exhaust gas purification system that has been improved by examining the current situation as described above, and a ship equipped with the exhaust gas purification system.

The exhaust gas purification system according to the invention of claim 1 includes, as an exhaust path of an engine for mounting on a ship, a main path communicating with the outside and a bypass path branched from a midway portion of the main path. And a bypass that communicates both of the bypass path and the main path in the composite casing, the selective catalyst reduction device that promotes the reduction of NOx in the exhaust gas of the engine is accommodated in the main path, And a bypass switching member for switching the exhaust gas movement direction between the main route and the bypass route, and a portion of the main route between the route switching member and the composite casing. Is arranged with a reducing agent injection body of a reducing agent supply device for supplying a reducing agent to the exhaust gas, and the inside of the composite casing is an exhaust gas moving method. Extending along the partition plate, said partitioned into main path side and said bypass path side, said bypass pathway in the composite casing is formed in a space surrounded by the partition plate and the composite casing, the composite casing An exhaust inlet portion on the main path side is formed in a taper shape that reduces a cross-sectional area toward the upstream side, and the partition plate is formed on the inner surface of the front portion of the exhaust inlet portion in the composite casing. By abutting and fixing the upstream side end portion, the exhaust inlet portion on the main path side and the exhaust inlet portion on the bypass path side cannot be communicated with each other in the composite casing .

  According to a second aspect of the present invention, in the exhaust gas purification system according to the first aspect, between the path switching member and the composite casing in the main path, the exhaust gas movement direction is downstream of the reducing agent injector. On the side, an exhaust mixer for mixing the exhaust gas and the reducing agent is arranged.

The invention according to claim 3, in the exhaust gas purifying system according to claim 1, wherein between the said composite casing and the path switching member of the main path, the exhaust gas moving direction upstream of the reducing agent injection member An exhaust mixer for mixing the exhaust gas and the reducing agent is arranged on the side or upstream and downstream in the exhaust gas movement direction .

  According to a fourth aspect of the present invention, in the exhaust gas purification system according to any one of the first to third aspects, the main path and the bypass path are merged at an outlet portion of the composite casing. .

  The invention of claim 5 relates to a ship, and a plurality of engines are mounted, and the exhaust gas purification system according to any one of claims 1 to 4 is made to correspond to each engine on a one-to-one basis. That's it.

  According to the first aspect of the present invention, the exhaust path of the ship-mounted engine includes a main path communicating with the outside and a bypass path branched from a midway portion of the main path, while the main path and the bypass path And a selective catalytic reduction device that promotes reduction of NOx in the exhaust gas of the engine is accommodated on the main path side in the composite casing, and the main path and the bypass path In the branch portion, a path switching member that switches the exhaust gas movement direction between the main path and the bypass path is disposed, and exhaust gas is disposed between the path switching member and the composite casing in the main path. Since the reducing agent supply body of the reducing agent supply device for supplying the reducing agent is arranged, the main path and the bypass path are separated from each other by a separate case. In comparison with the case where the bypass path is provided separately, the formation of the bypass path is simple, and the exhaust gas can be efficiently treated and the life of the selective catalytic reduction device can be extended, while reducing the manufacturing cost. I can plan.

  In addition, since the reducing agent injector of the reducing agent supply device is positioned outside the composite casing, the reducing agent is dispersed in the path between the path switching member and the composite casing in the main path. Thus, it is easy to set the length so that it can be properly mixed with the exhaust gas. Since the reducing agent injector is positioned between the path switching member and the composite casing in the main path, even if a malfunction such as a failure occurs in the path switching member, urea is disposed on the bypass path side. There is no fear of supplying water, and the problem of discharging unused ammonia as it is out of the ship can be eliminated.

  According to the invention of claim 2, the exhaust gas and the reducing agent are mixed between the path switching member and the composite casing in the main path on the downstream side in the exhaust gas movement direction with respect to the reducing agent injector. Since the exhaust mixer is disposed, the exhaust gas and the reducing agent can be mixed as uniformly as possible by the exhaust mixer, and the path between the path switching member and the composite casing in the main path is configured to be shorter. Thus, the entire exhaust path can be made compact. Furthermore, the installation space can be reduced by downsizing the composite casing. For this reason, for example, in a ship or the like, the composite casing can be easily mounted in a narrow engine room.

According to the invention of claim 1, the inside of the composite casing is partitioned into the main path side and the bypass path side by a partition plate extending along the exhaust gas movement direction, and therefore the partition plate is added. With only a simple configuration, two paths can be easily formed in the composite casing. Therefore, the manufacturing cost of the composite casing that houses the selective catalytic reduction device can be reduced.

  According to the invention of claim 4, since the main path and the bypass path are merged at the outlet of the composite casing, the exhaust gas purified through the main path and the exhaust gas that has passed through the bypass path Both the gas and the gas are sent to the downstream side of the exhaust path connected to the outlet portion of the composite casing. Therefore, the exhaust structure is simplified and the manufacturing cost is reduced.

  By the way, in the case of a ship equipped with a plurality of auxiliary engines (for example, power generation engines) which are engines, since the main path and the bypass path are separately provided in the conventional structure, the exhaust path has a radix of the engine. Twice the number is required, and the bypass route must be assembled at the shipyard, which requires work man-hours. On the other hand, according to the invention of claim 5, since the main path and the bypass path are combined in the composite casing, the number of exhaust paths may be the same as the number of the engines. Also, the bypass route assembly work at the shipyard is not necessary. Costs can be reduced by reducing work man-hours.

It is the whole ship side view. It is II-II front sectional drawing of FIG. It is a front view of a composite casing. It is a side view of a composite casing. It is a rear view of a composite casing. It is side surface sectional drawing of a composite casing. It is a cross-sectional perspective view which shows the internal structure of an exhaust mixer. It is the front view which looked at the exhaust mixer from the exhaust gas moving direction upstream. It is side surface sectional drawing of an exhaust mixer. It is side surface sectional drawing explaining the exhaust gas flow which goes to a composite casing from an exhaust mixer. It is side surface sectional drawing which shows the 1st another example of the arrangement | positioning aspect of an exhaust mixer. It is side surface sectional drawing which shows the 2nd another example of the arrangement | positioning aspect of an exhaust mixer.

  Hereinafter, an embodiment embodying the present invention will be described with reference to the drawings when applied to a diesel generator mounted on a ship.

(1). Outline of Ship First, an outline of the ship 1 will be described with reference to FIG. The ship 1 according to the embodiment includes a hull 2, a cabin 3 (bridge) provided on the stern side of the hull 2, a funnel 4 (chimney) arranged at the rear of the cabin 3, and a propeller 5 provided at the lower rear of the hull 2. And a rudder 6. In this case, the skeg 8 is integrally formed on the bottom 7 of the stern side. A propeller shaft 9 that rotationally drives the propeller 5 is supported on the skeg 8. A hold 10 is provided on the bow side and the center in the hull 2. An engine room 11 is provided on the stern side in the hull 2.

  In the engine room 11, a main engine 21 (diesel engine in the embodiment) and a speed reducer 22 that are driving sources of the propeller 5, and a power generation device 23 for supplying electric power to the electrical system in the hull 2 are arranged. Yes. The propeller 5 is rotationally driven by the rotational power from the main engine 21 via the speed reducer 22. The interior of the engine room 11 is partitioned vertically by an upper deck 13, a second deck 14, a third deck 15, and an inner bottom plate 16. In the embodiment, the main engine 21 and the speed reducer 22 are installed on the inner bottom plate 16 at the lowermost stage of the engine room 11, and the power generator 23 is installed on the third deck 15 at the middle stage of the engine room 11. Although detailed illustration is omitted, the hold 10 is divided into a plurality of sections.

  As illustrated in FIG. 2, the power generation device 23 includes a plurality of diesel generators 24 (three in the embodiment). The diesel generator 24 is configured by combining a power generation engine 25 (diesel engine in the embodiment) and a power generator 26 that generates power by driving the power generation engine 25. The diesel generator 24 is basically configured to operate efficiently in accordance with the required power amount in the hull 2. For example, all the diesel generators 24 are operated at the time of entry / exit that consumes a large amount of power, and an arbitrary number of diesel generators 24 are operated at the time of berthing where the power consumption is relatively low. The generated power generated by the operation of each generator 26 is supplied to the electrical system in the hull 2. Although not shown in detail, a power transducer is electrically connected to each generator 26. The power transducer detects power generated by each generator 26.

(2). Next, an exhaust system of the power generation device 23 will be described with reference to FIGS. Each power generation engine 25 is connected to an intake path (not shown) for air intake and an exhaust path 30 for exhaust gas discharge. The air taken in through the intake path is sent into each cylinder of the power generation engine 25 (inside the cylinder in the intake stroke). When the compression stroke of each cylinder is completed, the fuel sucked up from the fuel tank is pumped into the combustion chamber of each cylinder by the fuel injection device, and the expansion stroke accompanying the self-ignition combustion of the air-fuel mixture is performed by each combustion chamber.

  The exhaust passage 30 of each power generation engine 25 extends to the funnel 4 and directly communicates with the outside. As described above, since there are three power generation engines 25, there are three exhaust paths 30. The exhaust path 30 of each power generation engine 25 includes a main path 31 extending to the funnel 4, a bypass path 32 branched from a middle portion of the main path 31, and a composite casing communicating with both the main path 31 and the bypass path 32. 33. That is, in the embodiment, a plurality of power generation engines 25 are mounted, and an exhaust gas purification system including the main path 31, the bypass path 32, the composite casing 33, and the like is associated with each power generation engine 25 on a one-to-one basis.

  The composite casing 33 is made of a heat-resistant metal material and has a substantially cylindrical shape (in the embodiment, a rectangular tube shape), and is disposed above the third deck 15 on which the power generation engines 25 are disposed. In this case, the composite casing 33 is located on the upper side of the engine room 11 (on the second deck 14 on the upper stage of the engine room 11). On the main path 31 side in the composite casing 33, a NOx catalyst 34 and a slip treatment catalyst 35 (details will be described later) serving as a selective catalyst reduction device for promoting reduction of NOx in the exhaust gas of the power generation engine 25 are accommodated. ing. The bypass path 32 is a path for bypassing the exhaust gas without passing through the NOx catalyst 34 and the slip treatment catalyst 35. The main path 31 and the bypass path 32 are merged at the exhaust outlet portion 42 of the composite casing 33 (the downstream side in the exhaust gas movement direction (hereinafter simply referred to as the downstream side) from the slip treatment catalyst 35). As the selective catalyst reduction device, the NOx catalyst 34 may be used without the slip treatment catalyst 35.

  At a branch portion between the main path 31 and the bypass path 32 outside the composite casing 33, as a path switching member that switches the exhaust gas movement direction between the main path 31 and the bypass path 32, a gas-actuated main side switching valve 37 and A bypass side switching valve 38 is provided. The main side switching valve 37 is provided on the inlet side to the composite casing 33 in the main path 31. The bypass side switching valve 38 is provided on the inlet side to the composite casing 33 in the bypass path 32.

  Each of the switching valves 37 and 38 is for selecting a path through which the exhaust gas passes, and is configured such that if one is opened by compressed gas (air) from a gas supply source (not shown), the other is closed. Yes. In a state where the main side switching valve 37 is opened and the bypass side switching valve 38 is closed, the exhaust gas in the exhaust path 30 passes through the NOx catalyst 34 and the slip treatment catalyst 35 on the main path 31 side in the composite casing 33. Then, after being purified, it is discharged out of the ship 1. In a state in which the bypass side switching valve 38 is opened and the main side switching valve 37 is closed, the exhaust gas in the exhaust path 30 bypasses the NOx catalyst 34 and the slip treatment catalyst 35 and is not purified and bypasses the ship 1 To be released.

(3). Next, the structure of the composite casing 33 will be described with reference to FIGS. As described above, the composite casing 33 communicates with both the main path 31 and the bypass path 32. The main path 31 side in the composite casing 33 includes, in order from the upstream side in the exhaust gas movement direction (hereinafter simply referred to as the upstream side), a NOx catalyst 34 that promotes reduction of NOx in the exhaust gas, and an excessively supplied reducing agent. A slip treatment catalyst 35 that promotes an oxidation treatment of (urea water (urea aqueous solution), more specifically, ammonia after hydrolysis) is accommodated in series. Each of the catalysts 34 and 35 has a honeycomb structure composed of a large number of cells partitioned by porous (filterable) partition walls, and has a catalytic metal such as alumina, zirconia, vanadia / titania or zeolite. doing.

The NOx catalyst 34 selectively reduces NOx in the exhaust gas to the main path 31 side in the composite casing 33 by using ammonia generated by hydrolysis of urea water from the urea water injection nozzle 61 described later as a reducing agent. The sent exhaust gas is purified. The slip treatment catalyst 35 oxidizes unreacted (surplus) ammonia flowing out from the NOx catalyst 34 to harmless nitrogen. In this case, on the main path 31 side in the composite casing 33, the following reaction formula:
(NH ₂ ) ₂ CO + H ₂ O → 2NH ₃ + CO ₂ (hydrolysis)
NO + NO ₂ + 2NH ₃ → 2N ₂ + 3H ₂ O (reaction at NOx catalyst 34)
4NH ₃ + 3O ₂ → 2N ₂ + 6H ₂ O (reaction with slip treatment catalyst 35)
Will occur.

  As shown in detail in FIG. 6, both the main path 31 and the bypass path 32 are provided side by side in the composite casing 33. In this case, a partition plate 40 extending along the exhaust gas movement direction is disposed in the composite casing 33. The presence of the partition plate 40 partitions the composite casing 33 into a main path 31 side and a bypass path 32 side. By partitioning the inside of the composite casing 33 with the partition plate 40, when the exhaust gas passes through the bypass path 32, the heat of the exhaust gas is used to warm the NOx catalyst 34 and the slip treatment catalyst 35 on the main path 31 side. Is possible. For this reason, regardless of whether or not the exhaust gas is purified, the NOx catalyst 34 and the slip treatment catalyst 35 can always be warmed up to easily maintain the activated state. When exhaust gas passes through the main-side path 31, warm-up operation is not necessary, so that exhaust gas purification can be performed quickly.

  The upstream end of the partition plate 40 is abutted and fixed to the front inner surface of the exhaust inlet 41 located upstream of the NOx catalyst 62 in the main path 31 side in the composite casing 33. The exhaust inlet 41 on the main path 31 side in the composite casing 33 is formed in a tapered shape (conical shape) that decreases in cross-sectional area toward the upstream side. On the other hand, the downstream end portion of the partition plate 40 is interrupted in the exhaust outlet portion 42 on the downstream side of the slip treatment catalyst 35 in the composite casing 33. For this reason, in the exhaust outlet part 42 of the composite casing 33, the main path 31 side and the bypass path 32 side merge.

  On one side of the composite casing 33, a plurality of jet nozzles 43 serving as jets are attached to the upstream side of the NOx catalyst 34 and the upstream side of the slip treatment catalyst 35. In the embodiment, three jet nozzles 43 are provided on one side of the composite casing 33 on the upstream side of the NOx catalyst 34, and three jet nozzles 43 are also provided on one side of the composite casing 33 on the upstream side of the slip treatment catalyst 35. Provided. Compressed gas (air) from a gas supply source (not shown) is blown toward the NOx catalyst 34 and the slip treatment catalyst 35 by each blast nozzle 43. By the action of the blow nozzle 43, the dust accumulated on the main path 31 side in the composite casing 33 during use can be forcibly removed.

  A plurality of inspection opening windows 44 (three places in the embodiment) are formed on the other side surface of the composite casing 33. Each inspection opening window 44 is formed for the inspection and maintenance of the inside of the composite casing 33, the jet nozzle 43, the NOx catalyst 34, and the slip treatment catalyst 35. Each inspection opening window 44 is normally closed by a lid cover 45 so as to be opened and closed. Each lid cover 45 is detachably fastened to the peripheral edge of the corresponding inspection opening window 44 with a bolt.

  A main side inlet 47 and a bypass side inlet 48 are formed on the front side of the exhaust inlet 41 of the composite casing 33. The main side inlet 47 communicates with the main path 31 in the composite casing 33, and the bypass side inlet 48 communicates with the bypass path 32 in the composite casing 33. A main-side introduction pipe 51 that communicates with the main-side inlet 47 and a bypass-side introduction pipe 52 that communicates with the bypass-side inlet 48 are provided on the front outer surface side of the exhaust inlet 41 of the composite casing 33. The main side introduction pipe 51 and the bypass side introduction pipe 52 are connected to the bifurcated pipe 53 via relay pipes 55 and 56, respectively. In this case, the inlet side of the main relay pipe 55 is fastened to the main outlet part 57 of the bifurcated pipe 53 via a flange. The other end side of the main side relay pipe 55 communicates with the main side introduction pipe 51. An inlet side of the bypass side relay pipe 56 is fastened to the bypass side outlet portion 58 of the bifurcated pipe 53 via a flange. The outlet side of the bypass side relay pipe 56 is fastened with a bypass side introduction pipe 52 via an adjustment pipe 69 having a bellows structure for adjusting the length. The presence of the adjustment pipe 69 absorbs the extension of the introduction pipes 51 and 52 and the relay pipes 55 and 56 due to thermal expansion. It is sufficient that the control tube 69 is on either the main side or the bypass side. This is because both the main side and the bypass side are connected to the bifurcated pipe 53.

  Although not shown in detail, the inlet 59 of the bifurcated pipe 53 is connected to the upstream side of the main path 31 via a flange. The bifurcated pipe 53 corresponds to a branch portion between the main path 31 and the bypass path 32. A main-side switching valve 37 is provided in the main-side outlet 57 of the bifurcated pipe 53 that communicates with the main path 31 side in the composite casing 33. A bypass-side switching valve 38 is provided in the bypass-side outlet 58 of the bifurcated pipe 53 that communicates with the bypass path 32 in the composite casing 33. A main side valve driver 67 for switching and driving the main side switching valve 37 is provided on the outer peripheral side of the main side outlet pipe 57 of the main side relay pipe 55 and the bifurcated pipe 53. A bypass side valve driver 68 for switching the bypass side switching valve 38 is provided on the outer peripheral side of the bypass side relay pipe 56 and the bypass side outlet portion 58 of the bifurcated pipe 53. Both valve drivers 67 and 68 are arranged in parallel in the same manner as both relay pipes 55 and 56. On the rear surface side of the exhaust outlet portion 42 of the composite casing 33, an outlet 49 is formed close to the main path 31 side. An exhaust discharge pipe 60 communicating with the outflow port 49 is provided on the rear outer surface side of the exhaust outlet portion 42 of the composite casing 33. The exhaust discharge pipe 60 is connected to the downstream side of the main path 31 via a flange.

  Between the main side switching valve 37 and the main side introduction pipe 51 connected to the composite casing 33 in the main path 31, a reducing agent supply device that supplies urea water as a reducing agent to exhaust gas in order from the upstream side. A urea water injection nozzle 61 as a reducing agent injection body and an exhaust mixer 62 for mixing exhaust gas and urea water are arranged. The reducing agent supply device includes a urea water tank (not shown) for storing urea water, a feed pump (not shown) for sucking urea water from the urea water tank, and a urea water injection nozzle 61 provided in the main-side relay pipe 55. It has. The urea water is sent from the urea water tank to the urea water injection nozzle 61 by driving the feed pump, and the urea water is injected from the urea water injection nozzle 61 into the main relay pipe 55 in the form of a mist.

  A nozzle inspection window 63 for inspection and maintenance of the urea water injection nozzle 61 is provided in the vicinity of the urea water injection nozzle 61 in the main side relay pipe 55. The nozzle inspection window 63 is also normally closed with a lid cover 64 so that it can be opened and closed in the same manner as the inspection opening windows 44 described above. The lid cover 64 is detachably fastened to the peripheral edge of the nozzle inspection window 63 with bolts.

  An exhaust mixer 62 is provided between the main side relay pipe 55 and the main side introduction pipe 51. The exhaust mixer 62 is located downstream from the urea water injection nozzle 61 provided in the main-side relay pipe 55 by a predetermined distance. The predetermined distance in this case is a distance necessary for hydrolyzing the urea water injected from the urea water injection nozzle 61 into ammonia in the main-side relay pipe 55. As shown in FIGS. 7 to 10, the exhaust mixer 62 according to the embodiment includes a cylindrical mixer pipe body 71 having the same inner diameter as the main side relay pipe 55 and the main side introduction pipe 51, and the mixer pipe body 71. A plurality of mixing fins 72 (four in the embodiment) provided on the circumferential side and an axial core body 73 positioned at the axial core of the mixer tube 71 are provided. The swirl flow is generated in the exhaust gas passing through the exhaust mixer 62 and the mist-like urea water.

  Each mixing fin 72 is a member for turning the exhaust gas flow into a swirling flow, and is arranged radially on the inner peripheral side of the mixer tube 71 with the shaft core 73 as the center. In this case, the radially inner side end surface of each mixing fin 72 is fixed to the shaft core 73, and the radially outer side end surface of each mixing fin 72 is fixed to the inner peripheral surface of the mixer tube 71. Each mixing fin 72 is located at equal angles along the circumferential direction of the mixer tube 72 (positioned symmetrically about the shaft core 73). The number of mixing fins 72 is not limited to the four in the embodiment.

  The upstream side and the downstream side of each mixing fin 72 are configured to make a predetermined angle with respect to the exhaust gas movement direction (axial center direction of the mixer tube 71 etc.). That is, each mixing fin 72 is bent in the middle of the exhaust gas movement direction. In this case, each mixing fin 72 is bent so that the angle of the upstream fin plate portion 72a with respect to the exhaust gas movement direction is the inclination angle θ1, and the angle of the downstream fin plate portion 72b with respect to the exhaust gas movement direction is the inclination angle θ2. I am letting. The inclination angle θ2 of the downstream fin plate portion 72b is set larger than the inclination angle θ1 of the upstream fin plate portion 72a. That is, the inclination angles θ1 and θ2 of the fin plate portions 72a and 72b are larger on the downstream side than on the upstream side. In other words, the inclination angles θ1 and θ2 of the fin plate portions 72a and 72b increase continuously or stepwise from the upstream side toward the downstream side.

  The upstream tip portion of the shaft core 73 that supports the radially inner side end surface of each mixing fin 72 has a tapered shape (conical shape) that decreases in cross-sectional area toward the upstream side. Forming. Further, the downstream base end portion of the shaft core 73 is formed in a taper shape (cone shape) having a rear narrowing that reduces the cross-sectional area toward the downstream side. For this reason, the exhaust gas flowing into the vicinity of the shaft core of the mixer tube 71 is guided toward the mixing fins 72 on the radially outer side by the tapered upstream tip portion of the shaft core 73.

  As shown in FIGS. 4 and 5, a main side inlet temperature sensor that detects the temperature of exhaust gas flowing into the main path 31 side in the composite casing 33 is provided in the exhaust path inlet 41 on the main path 31 side of the composite casing 33. 65a is arranged. A bypass side inlet temperature sensor 65 b that detects the temperature of the exhaust gas flowing into the bypass path 32 in the composite casing 33 is disposed in the bypass side relay pipe 56. An outlet temperature sensor 65 c that detects the temperature of the exhaust gas that has passed through the main path 31 side or the bypass path 32 side is disposed in the exhaust discharge pipe 60 of the composite casing 33.

  As shown in FIGS. 3 to 5, a plurality of lifting metal fittings 66 are integrally provided on the upper outer peripheral side of the composite casing 33. In this case, two lifting metal fittings 66 (four in total) are attached to the upper side of the two side surfaces of the composite casing 33 having a substantially rectangular tube shape in parallel with each other. In an assembly factory of the ship 1, for example, the lifting metal fitting 66 group is locked to a hook (not shown) of a chain block, and the composite casing 33 is moved up and down by the chain block. The composite casing 33 can be easily assembled on the second deck 14).

  In the above configuration, when the main switching valve 37 is opened and the bypass switching valve 38 is closed, the exhaust gas passes through the main path 31 throughout. That is, it flows into the main path 31 side in the composite casing 33 via the main side outlet 57, the main side relay pipe 55, the exhaust mixer 62, the main side introduction pipe 51, and the main side inlet 47 of the bifurcated pipe 53, The NOx catalyst 34 and the slip treatment catalyst 35 are passed through for purification treatment.

  In this case, the exhaust gas containing the atomized urea water injected from the urea water injection nozzle 61 is guided to the exhaust mixer 62 through the main-side relay pipe 55. As a result of the upstream fin plate portion 72a of each mixing fin 72 changing the exhaust gas movement direction to the direction of the inclination angle θ1, and the downstream fin plate portion 72b further changing the exhaust gas movement direction to the direction of the inclination angle θ2. The exhaust gas containing urea water flows toward the inner peripheral surface of the mixer tube 71 and moves in the circumferential direction along the inner peripheral surface of the mixer tube 71. For this reason, a swirling flow of the exhaust gas is formed at the exhaust inlet 41 on the main path 31 side in the composite casing 33, and the exhaust gas and the urea water are smoothly and efficiently mixed. The exhaust inlet 41 on the main path 31 side in the composite casing 33 has a tapered shape (conical shape) that reduces the cross-sectional area toward the upstream side. The turning diameter becomes large. As a result, the exhaust gas reaches the NOx catalyst 34 on the main path 31 side in the composite casing 33 while being more uniformly mixed with the urea water.

  In the embodiment, the inclination angles θ1 and θ2 of the upstream fin plate portion 72a and the downstream fin plate portion 72b of each mixing fin 72 are made different, and the inclination angle θ2 of the downstream fin plate portion 72b is changed to the upstream fin plate portion 72a. Therefore, it is easy to form a large swirl flow while suppressing the flow resistance applied to the exhaust gas by each mixing fin. As described above, the exhaust gas flowing in the vicinity of the axial center of the mixer tube 71 is guided toward the mixing fins 72 on the radially outer side by the tapered upstream tip of the axial core 73. In this respect, the mixing efficiency of the exhaust gas and the urea water can be improved.

  The exhaust gas after the purification treatment flows from the outlet 49 of the exhaust outlet portion 42 of the composite casing 33 through the exhaust discharge pipe 60 to the downstream side of the exhaust passage 30 and is discharged outside the composite casing 33 and thus outside the ship 1. .

  Conversely, when the bypass side switching valve 38 is opened and the main side switching valve 37 is closed, the exhaust gas moves from the main path 31 to the bypass path 32. That is, it flows into the composite casing 33 via the bypass-side outlet 58, the bypass-side relay pipe 56, the bypass-side introduction pipe 52, and the bypass-side inlet 48 of the bifurcated pipe 53, and the NOx catalyst 34 and the slip treatment catalyst 35 are supplied to the composite casing 33. It bypasses the bypass path 32 without detouring and purifying. The exhaust gas that has passed through the bypass path 32 flows from the outlet 49 of the exhaust outlet portion 42 of the composite casing 33 to the downstream side of the exhaust path 30 through the exhaust discharge pipe 60, and is discharged outside the composite casing 33 and thus outside the ship 1. Is done.

  Therefore, when the switching operation of both switching valves 37 and 38 requires purification processing of exhaust gas (for example, during navigation within the regulated sea area) and when purification processing is not required (for example, during navigation outside the regulated sea area). In this case, the path through which the exhaust gas passes can be easily selected. Therefore, the exhaust gas can be processed efficiently according to the necessity of the purification process.

  In addition, although the exhaust mixer 62 of the embodiment is located downstream from the urea water injection nozzle 61 of the main-side relay pipe 55 by a predetermined distance, it is not limited to such a positional relationship. For example, as shown in FIG. 11, an exhaust mixer 62 may be disposed upstream of the urea water injection nozzle 61 so that the exhaust gas is swirled in advance before the urea water injection. As shown in FIG. 12, it is also possible to arrange the exhaust mixer 62 on both the upstream side and the downstream side with the urea water injection nozzle 61 interposed therebetween. The structures of the exhaust mixer 62 on the upstream side and the downstream side may be the same or different. If comprised in this way, it will become still easier to form a swirl | vortex flow and the further uniformization of the mixed state of exhaust gas and mist-like urea water can be aimed at.

(4). According to the above configuration, the exhaust path 30 of the engine 25 for mounting on the ship 1 includes the main path 31 communicating with the outside and the bypass path 32 branched from the middle part of the main path 31. Selective catalytic reduction that includes a composite casing 33 that allows both the main path 31 and the bypass path 32 to communicate with each other, and promotes reduction of NOx in the exhaust gas of the engine 25 on the main path 31 side in the composite casing 33. Apparatuses 34 and 35 are accommodated, and path switching members 37 and 38 for switching the exhaust gas movement direction between the main path 31 and the bypass path 32 are arranged at a branching portion 53 between the main path 31 and the bypass path 32. In the main path 31, between the path switching member 37 and the composite casing 33, exhaust gas is reduced with a reducing agent. Since the reducing agent supply body 61 of the reducing agent supply device for supplying the fuel is disposed, the bypass path 32 is formed as compared with the case where the main path 31 and the bypass path 32 are provided separately in separate casings. The manufacturing cost can be reduced while being simple and capable of efficiently treating the exhaust gas and extending the life of the selective catalyst reduction devices 34 and 35.

  In addition, since the reducing agent injector 61 and the exhaust mixer 62 of the reducing agent supply device are positioned outside the composite casing 33, the path switching member 37 and the composite casing 33 in the main path 31. It is easy to set the path between the length and the distance between the two so that the reducing agent can be dispersed and properly mixed with the exhaust gas. Since the reducing agent injector 61 is positioned between the path switching member 37 and the composite casing 33 in the main path 31, even if a malfunction such as a failure occurs in the path switching members 37 and 38. There is no fear of supplying urea water to the bypass path 32 side, and the problem of discharging unused ammonia as it is out of the ship can be eliminated.

  In the embodiment, between the path switching member 37 and the composite casing 33 in the main path 31, the exhaust gas and the reducing agent are mixed on the downstream side of the reducing agent injector 61 in the exhaust gas movement direction. Since the exhaust mixer 62 is disposed, the exhaust mixer 62 can mix the exhaust gas and the reducing agent as uniformly as possible, and the path between the path switching member 37 and the composite casing 33 in the main path 31. The exhaust path 30 as a whole can be configured compactly. Furthermore, the installation space can be reduced by reducing the size of the composite casing 33. For this reason, for example, in the ship 1 or the like, the composite casing 33 can be easily mounted in the narrow engine room 11.

  Further, since the inside of the composite casing 33 is partitioned into the main path 31 side and the bypass path 32 side by the partition plate 40 extending along the exhaust gas movement direction, the partition plate 40 is simply added. With only a simple configuration, the two paths 31 and 32 can be easily formed in the composite casing 33. Therefore, the manufacturing cost of the composite casing 33 that accommodates the selective catalyst reduction devices 34 and 35 can be reduced.

  Further, since the main path 31 and the bypass path 32 are merged at the outlet 42 of the composite casing 33, the exhaust gas purified through the main path 31 and the exhaust gas that has passed through the bypass path 32 are combined. Both the gas and the gas are sent to the downstream side of the exhaust passage 30 connected to the outlet portion 42 of the composite casing 33. Therefore, the exhaust structure is simplified and the manufacturing cost is reduced.

  By the way, in the case of the ship 1 equipped with a plurality of auxiliary engines (for example, power generation engines) that are the engines 25, since the main path 31 and the bypass path 32 are separately provided in the conventional structure, the exhaust path 30 is The number of the engines 25 is twice as many as the number of the engines 25, and the bypass path 32 must be assembled at the shipyard, which requires work man-hours. On the other hand, according to the embodiment, since the main path 31 and the bypass path 32 are grouped together by the composite casing 33, the number of exhaust paths 30 is the same as the number of the engines 25. Further, the work of assembling the bypass path 32 at the shipyard becomes unnecessary. Costs can be reduced by reducing work man-hours.

(5). In addition, the structure of each part is not limited to embodiment of illustration, A various change is possible in the range which does not deviate from the meaning of this invention. In each of the above-described embodiments, the present invention is applied to the exhaust gas purification system provided in the exhaust path 30 of the power generation engine 25. However, the present invention is not limited to this, for example, the exhaust gas purification system in the exhaust system of the main engine 21. You may apply.

DESCRIPTION OF SYMBOLS 1 Ship 11 Engine room 21 Main engine 22 Reduction gear 23 Electric power generation device 24 Diesel generator 25 Electric power generation engine 26 Generator 30 Exhaust path 31 Main path 32 Bypass path 33 Composite casing 34 NOx catalyst 35 Slip treatment catalyst 37 Main side switching valve 38 Bypass side switching valve 40 Partition plate 61 Urea water injection nozzle (reducing agent injection body)
62 Exhaust mixer

Claims (5)

A composite casing that communicates both the main path and the bypass path, as the exhaust path of the ship-mounted engine, including a main path that communicates with the outside and a bypass path that branches off from a middle portion of the main path. Prepared,
A selective catalytic reduction device that promotes reduction of NOx in the exhaust gas of the engine is accommodated on the main path side in the composite casing, and an exhaust gas moving direction is provided at a branch portion between the main path and the bypass path. A path switching member that switches between the main path and the bypass path,
Between the path switching member and the composite casing in the main path, a reducing agent injector of a reducing agent supply device that supplies a reducing agent to exhaust gas is disposed,
The composite casing is partitioned into a main path side and a bypass path side by a partition plate extending along the exhaust gas movement direction, and the bypass path in the composite casing is the composite casing and the partition plate. Formed in the enclosed space ,
An exhaust inlet portion on the main path side in the composite casing is formed in a tapered shape so that a cross-sectional area is reduced toward the upstream side, and the front inner surface of the exhaust inlet portion in the composite casing is By abutting and fixing the upstream end of the partition plate, the exhaust inlet part on the main path side and the exhaust inlet part on the bypass path side are not allowed to communicate in the composite casing.
Exhaust gas purification system. An exhaust mixer that mixes the exhaust gas and the reducing agent is disposed between the path switching member and the composite casing in the main path on the downstream side in the exhaust gas movement direction from the reducing agent injector. ,
The exhaust gas purification system according to claim 1. Of the main path, between the path switching member and the composite casing, the exhaust gas and the reduction are located upstream of the reducing agent injector in the exhaust gas movement direction, or upstream and downstream in the exhaust gas movement direction. An exhaust mixer that mixes the agent is placed.
The exhaust gas purification system according to claim 1. In the outlet portion of the composite casing, the main path and the bypass path are merged,
The exhaust gas purification system according to any one of claims 1 to 3. A plurality of engines are mounted, and the exhaust gas purification system according to any one of claims 1 to 4 is made to correspond to each engine on a one-to-one basis.
Ship.

Images