WO2010032738A1

WO2010032738A1 - Exhaust gas purifying device

Info

Publication number: WO2010032738A1
Application number: PCT/JP2009/066131
Authority: WO
Inventors: 徹待田; 横山　哲也; 井上　剛; 文哉古東; 和睦鬼追
Original assignee: ヤンマー株式会社
Priority date: 2008-09-17
Filing date: 2009-09-16
Publication date: 2010-03-25

Abstract

An exhaust gas purifying device is provided with a NOx catalyst (62) for promoting reduction of NOx in exhaust gas from electric power generating engines (12), an aqueous urea solution discharge nozzle (47) for supplying a NOx reducing aqueous urea solution to the exhaust gas, and an electric power transducer (15). Exhaust routes (25) of the electric power generating engines (12) are merged into a single collecting route (26). The collecting route (26) is provided with the aqueous urea solution discharge nozzle (47) and the NOx catalyst (62) which are arranged in that order from the upstream side. A bypass route (29) is connected in a branched manner between a post-processing device (27) and that portion of the collecting route (26) at which the collecting route (26) joins the downstream-most exhaust route (25). Switching valves (30, 31) are provided to the entrance side of the bypass route (29) and to the downstream side of that portion of the collecting route (26) at which the collecting route (26) is branched to the bypass route (29).

Description

Exhaust gas purification device

The present invention relates to an exhaust gas purification device for purifying exhaust gas in an internal combustion engine (engine) such as a diesel engine.

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 plurality of diesel generators are provided that are a combination of an engine and a generator that generates electricity by driving the diesel engine (see, for example, Patent Document 1).

Diesel engine is known to be one of the most energy efficient among 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.

JP 2006-341742 A

By the way, the exhaust gas of a diesel engine contains a large amount of nitrogen oxides, sulfur oxides and particulate matter 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 considered to be the cause of acid rain.

Therefore, for example, in a machine that drives a plurality of diesel generators (diesel engines) such as a ship, it is understood that the amount of NOx emission is extremely large and the burden on the global environment is large. In consideration of the global environment, it is necessary to remove NOx in the exhaust gas as much as possible. For this purpose, it is required to reduce NOx and make it harmless with a simple configuration and efficiently.

The present invention is intended to meet such a demand.

An exhaust gas purification apparatus according to claim 1 is a NOx catalyst that promotes reduction of NOx in exhaust gas from a plurality of engines, and a reducing agent supply unit that supplies a reducing agent for NOx reduction to the exhaust gas. And NOx detecting means for detecting the NOx concentration in the exhaust gas, and the exhaust paths of the engines merge into one collective path, and the collective path in order from the upstream side A reducing agent supply unit and the NOx catalyst are arranged, and a bypass path for bypassing the NOx catalyst is provided between the joining part of the most downstream exhaust path in the collecting path and the NOx catalyst. Branch connection is made, and a path switching member that opens and closes each path is provided on the downstream side of the branch path to the bypass path in the collective path and on the inlet side of the bypass path. It is.

According to a second aspect of the present invention, the exhaust gas purifying apparatus according to the first aspect is configured to adjust a reducing agent supply amount from the reducing agent supply unit based on detection information of the NOx detecting means. Is.

According to a third aspect of the present invention, in the exhaust gas purifying apparatus according to the first or second aspect, each exhaust path is provided with an opening / closing member for opening / closing the exhaust path.

According to a fourth aspect of the present invention, in the exhaust gas purifying apparatus according to the first aspect, the casing housing the NOx catalyst is provided with a silencer for attenuating exhaust noise of the exhaust gas.

According to a fifth aspect of the present invention, in the exhaust gas purifying apparatus according to the fourth aspect, the outlet side of the bypass path is connected in communication with the silencer of the casing.

According to a sixth aspect of the present invention, in the exhaust gas purifying apparatus according to the second aspect, a compressed gas from a gas supply source toward the NOx catalyst is disposed upstream of the NOx catalyst in a casing housing the NOx catalyst. There is a fumarole part for ejecting the gas.

According to a seventh aspect of the present invention, in the exhaust gas purifying apparatus according to the second aspect, the casing containing the NOx catalyst is urged to oxidize excess reducing agent supplied downstream from the NOx catalyst. A slip treatment catalyst is arranged.

According to an eighth aspect of the present invention, in the exhaust gas purifying apparatus according to the second aspect, the NOx detecting means detects an amount of electric power of a generator that generates electric power by driving each engine, and in the exhaust gas based on the detection result. It is configured to indirectly obtain the NOx concentration.

According to the present invention, a NOx catalyst that promotes reduction of NOx in exhaust gas from a plurality of engines, a reducing agent supply unit that supplies a reducing agent for NOx reduction to the exhaust gas, and NOx in the exhaust gas NOx detection means for detecting the concentration, and the exhaust paths of the engines merge into one collective path, so that the exhaust structure in the case of having a plurality of engines can be simplified.

In addition, the reducing agent supply unit and the NOx catalyst are arranged in order from the upstream side in the collecting path, and between the joining part of the collecting path with the most downstream exhaust path and the NOx catalyst. The bypass path for bypassing the NOx catalyst is branched and connected to the downstream side of the branch path to the bypass path and the inlet side of the bypass path. When the exhaust gas purification process is required by switching the open / closed state of both the path switch members (for example, during navigation in a regulated sea area), the purification process is performed. When unnecessary (for example, during navigation outside the regulated sea area), the route through which the exhaust gas passes can be easily selected. Therefore, there is an effect that the exhaust gas can be efficiently processed.

According to the invention of claim 2, since it is configured to adjust the reducing agent supply amount from the reducing agent supply unit based on the detection information of the NOx detecting means, an amount commensurate with the NOx concentration in the exhaust gas. The reducing agent can be supplied to the collecting route. Therefore, NOx in the exhaust gas can be efficiently decomposed into nitrogen and water by the action of the NOx catalyst.

According to the invention of claim 3, since each exhaust path is provided with an opening and closing member for opening and closing the exhaust path, by opening and closing the corresponding opening and closing member according to the state of each engine, It is possible to easily and reliably prevent the exhaust gas from flowing backward from the collecting path toward the stopped engine.

According to the invention of claim 4, the casing containing the NOx catalyst is equipped with a silencer for attenuating exhaust noise of the exhaust gas, so the NOx catalyst and the silencer are combined in a single casing. It can be packaged, and the downstream side of the exhaust structure can be made compact.

According to the invention of claim 5, since the outlet side of the bypass path is connected to the silencer of the casing, the exhaust gas purified by passing through the NOx catalyst and the NOx catalyst are bypassed. The exhaust gas passing through the bypass path can be sent to the same silencer. Therefore, the exhaust structure can be simplified and the manufacturing cost can be reduced.

According to the sixth aspect of the present invention, the casing containing the NOx catalyst is provided with an squirting section that ejects compressed gas from a gas supply source toward the NOx catalyst on the upstream side of the NOx catalyst. By the action of the squirting part, the dust accumulated in the NOx catalyst can be forcibly removed after a long period of use.

According to the seventh aspect of the present invention, since the slip treatment catalyst that promotes the oxidation treatment of the excessively supplied reducing agent is disposed upstream of the NOx catalyst in the casing that houses the NOx catalyst. It is possible to prevent the excess reducing agent that tries to pass through the NOx catalyst unreacted from leaking out as it is. In addition, since the NOx catalyst and the slip treatment catalyst are packaged, the downstream side of the exhaust structure can be made compact.

According to an eighth aspect of the present invention, the NOx detecting means is configured to detect a power generation amount of a power generator that generates power by driving each engine, and indirectly determine the NOx concentration in the exhaust gas based on the detection result. Therefore, a sensor dedicated to NOx concentration detection is not required, and the configuration can be simplified and the manufacturing cost can be reduced.

It is the whole ship side view. It is a schematic system diagram of a power generator. It is explanatory drawing of the fuel system | strain in an electric power generating apparatus. It is explanatory drawing of the exhaust system of a generator, and a reducing agent supply apparatus. It is side surface sectional drawing of a catalyst apparatus. It is side surface sectional drawing explaining the flow of the exhaust gas to a catalyst apparatus.

Hereinafter, an embodiment embodying the present invention will be described with reference to drawings (FIGS. 1 to 6) in a case where the present invention is applied to a plurality of diesel generators 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 is provided in a hull 2, a cabin 4 provided in a rear part on the deck 3 in the hull 2, a funnel 5 (chimney) arranged behind the cabin 4, and a lower rear part of the hull 2. The propeller 6 and the rudder 7 are provided. Installed at the rear of the hull 2 are a main engine 8 (diesel engine in the embodiment) and a speed reducer 9 which are driving sources of the propeller 6, and a power generator 10 for supplying power to the electrical system in the ship 2. Has been. The propeller 6 is rotationally driven by the rotational power from the main engine 8 via the speed reducer 9.

(2). Next, the structure of the power generation device 10 will be described with reference to FIG.

The power generation apparatus 10 includes a plurality of diesel generators 11 (three in the embodiment) that combine a power generation diesel engine 12 (hereinafter referred to as a power generation engine) and a power generator 13 that generates power by driving the power generation engine 12. ). These diesel generators 11 are configured to operate efficiently in accordance with the required power amount in the ship 2. For example, all the diesel generators 11 are operated at the time of navigation that consumes a large amount of power, and an arbitrary number of diesel generators 11 are operated at the time of berthing where the power consumption is relatively low.

The generated power generated by driving each generator 13 is supplied to the electrical system in the ship 2. Each generator 13 is electrically connected to a power transducer 15 in the generator control panel 14. The power transducer 15 is for detecting the power generated by each generator 13. Based on the detection information of the power transducer 15, the drive of each power generation engine 12 is controlled so that the generated power matches the target power set in advance on the generator control panel 14. The power transducer 15 is also electrically connected to a controller 55 of a reducing agent supply device 43 described later.

(3). Next, the fuel system of the power generation apparatus 10 will be described with reference to FIGS. 2 and 3.

A fuel tank 16 for storing fuel (heavy oil) of each power generation engine 12 is installed in the hull 2. One supply pipe 17 is connected to the fuel tank 16. A fuel inlet valve 18, a fuel filter 19, and a fuel flow meter 20 are provided on the upstream side of the supply pipeline 17. The fuel flow meter 20 is electrically connected to a controller 55 of a reducing agent supply device 43 described later.

A plurality of feed pipes 21 (three in the embodiment) extend from the downstream side of the fuel flow meter 20 in the supply pipe 17 and are connected to the fuel pump 16 of the corresponding power generation engine 12. Yes. The fuel sent to the fuel pump 16 is injected into a combustion chamber (not shown) for each cylinder in the power generation engine 12 by a fuel injection device (not shown) provided in the power generation engine 12. .

A return chamber 22 is provided in the middle of each feed line 21. A return line 23 extending from the fuel injection device to the outside of the power generation engine 12 is connected to the fuel tank 16 via a return chamber 22. Accordingly, unused surplus fuel in the power generation engine 12 is returned to the fuel tank 16 through the return line 23. A check valve 24 is provided downstream of the return chamber 22 in the return line 23.

(4). Next, an intake / exhaust system of the power generation apparatus 10 will be described with reference to FIGS. 2 and 4.

Each power generation engine 12 is connected to an intake path (not shown) for air intake and an exhaust path 25 for exhaust gas discharge. The air taken in through the intake path is sent into each cylinder of the power generation engine 12 (inside the cylinder in the intake stroke). When the compression stroke of each cylinder is completed, the fuel sucked up from the fuel tank 16 is pumped into the combustion chamber (sub chamber) for each cylinder by the fuel injection device, so that the air-fuel mixture is self-ignited in each combustion chamber. An expansion stroke accompanying combustion is performed.

All the exhaust paths 25 of each power generation engine 12 merge into one collective path 26. Thus, the exhaust structure in the case of having a plurality of power generation engines 12 is simplified. The collecting path 26 extends to the funnel 5, and a post-processing device 27 that mainly purifies exhaust gas is provided in the middle of the collecting path 26. In the exhaust stroke after the expansion stroke, the exhaust gases sent from the plurality of power generation engines 12 to the exhaust passages 25 are collected in the collecting passage 26 and released to the outside of the ship 1 via the post-processing device 27. Will be.

Each exhaust passage 25 is provided with an air-operated opening / closing valve 28 as an opening / closing member for opening / closing it. Each on-off valve 28 is opened and closed according to the state of the corresponding power generation engine 12. That is, the open / close valve 28 for the power generation engine 12 being driven is opened, and the open / close valve 28 corresponding to the stopped power generation engine 12 is closed. For this reason, it is possible to easily and reliably prevent the exhaust gas from flowing backward from the collecting path 26 toward the stopped power generation engine 12.

In order to bypass the NOx catalyst 62 and the slip treatment catalyst 63 (details will be described later) in the post-treatment device 27 between the joining path 26 and the post-treatment device 27 in the collecting passage 26. The bypass path 29 is connected. The outlet side of the bypass path 29 is connected to the rear portion of the post-processing device 27, specifically, to the downstream side of the NOx catalyst 62 and the slip processing catalyst 63 described later.

A gas-operated collective switching valve 30 is provided as a path switching member for opening and closing the part of the collective path 26 downstream of the branch part to the bypass path 29 (between the branch part and the post-processing device 27). Is provided. Further, a gas-operated bypass side switching valve 31 as a path switching member is provided on the inlet side of the bypass path 29.

These switching

valves

30 and 31 are for selecting a path through which the exhaust gas passes, and have a relationship that when one is opened, the other is closed. In a state where the collecting side switching valve 30 is opened and the bypass side switching valve 31 is closed, the exhaust gas collected in the collecting path 26 passes through the NOx catalyst 62 and the slip processing catalyst 63 in the aftertreatment device 27 and is purified. After being processed, it is discharged out of the ship 1. In a state where the bypass side switching valve 31 is opened and the collecting side switching valve 30 is closed, the exhaust gas collected in the collecting path 26 is purified by bypassing the NOx catalyst 62 and the slip processing catalyst 63 in the aftertreatment device 27. It is discharged out of the ship 1 without processing.

As described above, each

valve

28, 30, 31 is a gas-operated type, and each drive unit is connected to a gas trunk line 33 extending from a gas supply source 32 via a gas branch line 34. The gas supply source 32 of the embodiment is for supplying air (which may be nitrogen gas) as compressed gas for operating the

valves

28, 30 and 31. A gate valve 35 and a pressure reducing valve 36 are provided in the middle of each gas branch line 34 in order from the upstream side.

The outlet side of the gas trunk line 33 is connected to a front part of the post-processing device 27, specifically, to a squirting nozzle 37 as a squirting part provided at a portion upstream of the NOx catalyst 62 and the slip processing catalyst 63 described later. It is connected. The jet nozzle 37 blows the compressed gas from the gas supply source 32 toward the NOx catalyst 62 and the slip treatment catalyst 63, and the action of the jet nozzle 37 accumulates in the post-treatment device 27 over a long period of use. It becomes possible to forcibly remove dust.

A gate valve 38, a pressure reducing valve 39, an air filter 40, a reducer 41, and a squirting electromagnetic valve 42 are arranged between the most downstream air branch pipe 34 and the squirting nozzle 37 in the gas trunk line 33 in order from the upstream side. Is provided. The fusible solenoid valve 42 is electrically connected to a controller 55 of a reducing agent supply device 43 described later, and is configured to open and close based on control information from the controller 55.

(5). Next, the structure of the reducing agent supply device 43 will be described with reference to FIGS. 2 and 4.

The reducing agent supply device 43 is for supplying a reducing agent for NOx reduction to the exhaust gas in the collecting path 26, and includes a reducing agent supply passage 44 and a reducing agent control panel 45. One end side of the reducing agent supply passage 44 is connected to a urea water tank 46 for storing a urea aqueous solution (hereinafter referred to as urea water) as a reducing agent, while the other end side is switched to the bypass side in the collective path 26. It is connected to a urea water injection nozzle 47 as a reducing agent supply unit provided between the valve 31 and the post-processing device 27.

In the reducing agent supply passage 44, a urea water inlet valve 48, a reducer 49, a feed pump 50, a urea water filter 51, a urea water flow meter 52, an electromagnetic solenoid valve 53 for injection, and the like are provided in this order from the upstream side. The feed pump 50 sucks up urea water in the urea water tank 46 and discharges it toward the urea water injection nozzle 47. An electric motor 54 is connected to the feed pump 50. The urea water supply amount from the feed pump 50 is adjusted by adjusting the rotational drive amount of the electric motor 54 based on control information from the controller 55 described later via the inverter 56. The injection solenoid valve 53 is electrically connected to a controller 55 described later, and is configured to open and close based on control information from the controller 55.

The reducing agent control panel 45 includes a controller 55 as a control means, an inverter 56, a temperature controller 57, and a pressure sensor 58 as a clogging detection means for detecting a clogged state of the post-processing device 27. The controller 55 mainly performs a reducing agent adjustment control to operate the feed pump 50 and the injection electromagnetic valve 53 so that an appropriate amount of urea water corresponding to the NOx concentration in the exhaust gas is supplied to the collecting path 26. To do.

Although details are not shown, the controller 55 includes a CPU for executing various arithmetic processes and controls, a ROM for storing control programs and data, a RAM for temporarily storing control programs and data, and an input / output It has an interface.

The controller 55 is electrically connected to the electric motor 54 via the inverter 56, while the temperature sensor 59 for detecting the exhaust gas temperature in the collective path 26 is electrically connected via the temperature regulator 57. Has been. Further, the controller 55 includes a power transducer 15 of the generator control panel 14, a fuel flow meter 20, a urea water flow meter 52, a pressure sensor 58, a urea water amount sensor 60 for detecting a urea water storage amount, a fumarole electromagnetic valve 42, and The injection solenoid valve 53 is also electrically connected.

The pressure sensor 58 as clogging detection means is provided at the front portion of the post-processing device 27, specifically, at the upstream side of the NOx catalyst 62 and the slip processing catalyst 63, which will be described later, in the same manner as the above-described nozzle 35. ing. In the embodiment, the pressure (reference pressure value) on the upstream side of the NOx catalyst 62 in a new state in which dust is not accumulated in the post-processing device 27 is stored in advance in the ROM of the controller 55 and the like at the same measurement location. The current pressure is detected by the pressure sensor 58, a pressure difference between the reference pressure value and the detected value of the pressure sensor 58 is obtained, and the amount of dust accumulated in the post-processing device 27 is converted based on the pressure difference.

When the pressure difference becomes equal to or larger than the set value, the jet solenoid valve 42 is opened by a command from the controller 55, compressed gas is sent from the gas supply source 32 to the jet nozzle 37, and the NOx catalyst 62 and slip are sent from the jet nozzle 37. The compressed gas is blown toward the processing catalyst 63. In addition, pressure sensors may be arranged on the upstream and downstream sides of the collecting path 26 with the post-processing device 27 interposed therebetween, and the dust accumulation amount of the post-processing device 27 may be converted from the difference between the detected values.

The temperature sensor 59 for detecting the exhaust gas temperature in the collecting path 26 is provided between the urea water injection nozzle 47 and the post-processing device 27 in the collecting path 26. In the embodiment, when the temperature detected by the temperature sensor 59 reaches a predetermined temperature (for example, 305 ° C.) or more, the injection solenoid valve 53 is opened by a command from the controller 55, and the urea pump is driven from the urea water tank 46 by driving the feed pump 50. Urea water is sent to the water injection nozzle 47, and urea water is injected from the urea water injection nozzle 47 into the collecting path 26.

The urea water amount sensor 60 for detecting the urea water storage amount is a float type sensor and is disposed in the urea water tank 46. In this case, the urea water storage amount in the urea water tank 46 is detected based on the change in the vertical height position of the urea water amount sensor 60.

The controller 55 is configured to adjust the amount of urea water supplied from the feed pump 50 by adjusting the rotational drive amount of the electric motor 54 via the inverter 56 based on the generated power amount detected by the power transducer 15. Has been. This is because the NOx concentration in the exhaust gas is proportional to the total amount of power generated by the diesel generator 11 group (or the total output (or total load) of the power generation engine 12 group). Therefore, the urea water supply amount (reducing agent supply amount) necessary for NOx reduction is proportional to the total power generation amount, that is, the NOx concentration in the exhaust gas. Here, although illustration is omitted, the relationship between the amount of urea water supply and the amount of generated power necessary for NOx reduction is stored in advance in the controller 55 (for example, ROM) in a map format or a function table format, for example. Yes.

In this case, the controller 55 obtains the urea water supply amount necessary for the reduction of NOx from the total amount of generated power detected by the power transducer 15 and the map or function table stored in advance in the controller 55, and obtains the obtained amount. The electric motor 54 is rotationally driven to adjust the operation amount of the feed pump 50 so as to inject the supplied amount of urea water from the urea water injection nozzle 47 within the appropriate time.

The power transducer 15 of the embodiment corresponds to NOx detection means. That is, the power transducer 15 detects the total amount of power generated by the group of generators 13 and indirectly determines the NOx concentration in the exhaust gas based on the detection result of the power transducer 15. The NOx detection means is not limited to the power transducer 15 and may be one that detects the output of each power generation engine 12 or may be one that detects the load of each power generation engine 12 from the fuel injection amount. Alternatively, the NOx concentration in the exhaust gas may be directly detected.

(6). Structure of Post-Processing Device Next, the structure of the post-processing device 27 will be described with reference to FIGS. 2 and 4 to 6.

The post-treatment device 27 was supplied in excess from a NOx catalyst 62 for promoting the reduction of NOx in the exhaust gas in order from the upstream side in the post-treatment casing 61 made of a heat-resistant metal material formed in a substantially cylindrical shape. The slip treatment catalyst 63 that promotes the oxidation treatment of the reducing agent (in the embodiment, ammonia after hydrolysis) and the silencer 64 that attenuates the exhaust sound of the exhaust gas are accommodated in series. Each of the

catalysts

62 and 63 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. is doing.

The NOx catalyst 62 uses the ammonia produced by the hydrolysis of the urea water from the urea water injection nozzle 47 as a reducing agent to selectively reduce NOx in the exhaust gas, whereby the exhaust gas sent into the aftertreatment device 27. Is to purify. The slip treatment catalyst 63 oxidizes unreacted (surplus) ammonia flowing out of the NOx catalyst 62 to harmless nitrogen. In this case, in the post-processing casing 61, 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 with NOx catalyst 62)
4NH ₃ + 3O ₂ → 2N ₂ + 6H ₂ O (reaction at slip treatment catalyst 63)
Will occur.

The silencer 64 is formed on the rear side of the post-processing casing 61. The rear side of the post-processing casing 61 is closed by two

cover plates

65 and 66, and a substantially cylindrical discharge pipe 67 passes through both the

cover plates

65 and 66. The outlet side of the discharge pipe 67 communicates with the outlet of the post-processing casing 61. The front and

rear cover plates

65, 66 of the discharge pipe 67 are closed by a closing plate 68, and a plurality of communication holes 69, 70 are formed in the peripheral wall portions on both sides of the discharge pipe 67 with the closing plate 68 interposed therebetween. Is formed. Between the

lid plates

65 and 66 in the post-processing casing 61 is a resonance chamber 71 that communicates with the inside of the discharge pipe 67 via a plurality of communication holes 69 and 70.

Therefore, the exhaust gas that has entered the upstream side of the discharge pipe 67 passes through the downstream side of the discharge pipe 67 via the upstream side communication hole 69, the resonance chamber 71, and the downstream side communication hole 70, and is outside the post-processing casing 61. Will be released.

The outlet side of the bypass path 29 is connected between the slip treatment catalyst 63 and the front lid plate 65 in the post-treatment casing 61. For this reason, as shown in FIG. 6A, when the collecting side switching valve 30 is opened and the bypass side switching valve 31 is closed, the exhaust gas collected in the collecting path 26 becomes the NOx catalyst 62 and the slip treatment catalyst 63. It goes through the purification process. The exhaust gas after the purification treatment enters the downstream side of the exhaust pipe 67 from the upstream side of the exhaust pipe 67 via the upstream communication hole 69, the resonance chamber 71, and the downstream communication hole 70. It is discharged out of the processing casing 61 and out of the ship 1.

Further, as shown in FIG. 6B, when the bypass side switching valve 31 is opened and the collecting side switching valve 30 is closed, the exhaust gas collected in the collecting path 26 passes through the NOx catalyst 62 and the slip treatment catalyst 63. It enters the upstream side of the discharge pipe 67 without detouring and purifying. Then, the exhaust gas passes through the downstream side of the discharge pipe 67 via the upstream side communication hole 69, the resonance chamber 71, and the downstream side communication hole 70, and is discharged outside the post-processing casing 61 and thus outside the ship 1. The

Therefore, the exhaust gas purification process is required by switching the open / close state of both switching valves 30 and 31 (for example, while navigating within the regulated sea area), and when the purification process is not necessary (for example, navigating outside the regulated sea area). In the middle), the route through which the exhaust gas passes can be easily selected, and the exhaust gas can be processed efficiently.

(7). Operation and Effect According to the above configuration, the exhaust path 25 of each power generation engine 12 merges into one collective path 26, so that the exhaust structure when a plurality of power generation engines 12 are provided can be simplified. Further, a urea water injection nozzle 47 and a NOx catalyst 62 as a reducing agent supply unit are arranged in order from the upstream side in the collecting path 26, and exhaust gas is extracted from the total amount of generated power detected by the power transducer 15. Since the NOx concentration in the gas, and hence the urea water supply amount (reducing agent supply amount) necessary for NOx reduction, is grasped, an amount of urea water corresponding to the NOx concentration in the exhaust gas can be supplied to the collecting path 26. Therefore, NOx in the exhaust gas can be efficiently decomposed into nitrogen and water by the action of the NOx catalyst 62 in the aftertreatment device 27. Further, since urea water in an amount corresponding to the NOx concentration in the exhaust gas is supplied to the collecting path 26, ammonia slip that releases unreacted (excess amount) ammonia to the outside can be suppressed.

Each exhaust passage 25 is provided with an air-operated opening / closing valve 28 as an opening / closing member for opening / closing the exhaust passage 25, so that the corresponding opening / closing valve 28 is opened / closed according to the state of each power generation engine 12. Further, it is possible to easily and reliably prevent the exhaust gas from flowing backward from the collective path 26 toward the stopped power generation engine 12.

In the post-processing casing 61 that accommodates the NOx catalyst 62, on the upstream side of the NOx catalyst 62, a blast nozzle 37 is provided as a squirting section that ejects compressed gas from the gas supply source 32 toward the NOx catalyst 62. Thus, the action of the blow nozzle 37 can forcibly remove the dust accumulated in the NOx catalyst 62 over a long period of use.

In the post-treatment casing 61 that accommodates the NOx catalyst 62, a slip treatment catalyst 63 that promotes the oxidation treatment of the extra supplied reducing agent (in the embodiment, ammonia after hydrolysis) is disposed downstream of the NOx catalyst 62. Therefore, the excess reducing agent (ammonia) that is about to pass through the NOx catalyst 62 without being reacted can be rendered harmless by oxidizing it with nitrogen, and the possibility of ammonia remaining in the exhaust gas can be reliably avoided. . Further, the NOx catalyst 62 and the slip treatment catalyst 63 can be packaged, and the downstream side of the exhaust structure can be configured compactly.

Further, the power transducer 15 as the NOx detecting means detects the total amount of power generated by the generator 13 group, and the NOx concentration in the exhaust gas is indirectly obtained based on the detection result of the power transducer 15. Therefore, there is no need for a dedicated sensor for NOx concentration detection, and the configuration can be simplified and the manufacturing cost can be reduced.

In the embodiment, a bypass path 29 for bypassing the NOx catalyst 62 is branched and connected between a portion where the exhaust path 25 in the collecting path 26 joins with the downstream exhaust path 25 and the aftertreatment device 27. 26 are provided with switching

valves

30 and 31 as path switching members for opening and closing the

paths

26 and 29 on the downstream side of the branching portion to the bypass path 29 and the inlet side of the bypass path 29. When the switching operation of both switching

valves

30 and 31 is switched, the exhaust gas needs to be purified (for example, while navigating in the regulated sea area), or the purification process is not necessary (for example, navigating outside the regulated sea area). ), The route through which the exhaust gas passes can be easily selected, and the exhaust gas can be processed efficiently.

Since the post-treatment casing 61 that accommodates the NOx catalyst 62 includes a silencer 64 for attenuating exhaust noise of the exhaust gas, the NOx catalyst 62, the slip treatment catalyst 63, and the silencer 64 are treated as a single post-treatment. The casing 61 can be packaged, and the downstream side of the exhaust structure can be configured compactly.

Further, since the outlet side of the bypass path 29 is connected to the silencer 64 of the post-processing casing 61, the exhaust gas purified by passing through the NOx catalyst 62 and the slip processing catalyst 63, the NOx catalyst 62, and the slip The exhaust gas that bypasses the processing catalyst 63 and passes through the bypass path 29 can be sent to the same silencer 64. Therefore, the exhaust structure can be simplified and the manufacturing cost can be reduced.

The configuration of each part is not limited to the illustrated embodiment, and various modifications can be made without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 Ship 10 Power generator 11 Diesel generator 12 Diesel engine 13 Power generator 14 Generator control panel 15 Power transducer 25 Exhaust path 26 Collecting path 27 Post-processing device 28 Open / close valve 29 Bypass path 30 Collecting side switching valve 31 Bypass side switching Valve 32 Gas supply source 42 Pneumatic valve 43 Reducing agent supply device 44 Reducing agent supply passage 45 Reducing agent control panel 46 Urea water tank 47 Urea water injection nozzle 50 Feed pump 53 Injection electromagnetic valve 54 Electric motor 55 As a control means Controller 58 Pressure sensor 59 Temperature sensor 61 Aftertreatment casing 62 NOx catalyst 63 Slip treatment catalyst 64 Silencer

Claims

NOx catalyst for promoting reduction of NOx in exhaust gas from a plurality of engines, a reducing agent supply unit for supplying a reducing agent for NOx reduction to the exhaust gas, and NOx for detecting NOx concentration in the exhaust gas Detection means,
The exhaust paths of the engines merge into one collecting path, and the reducing agent supply unit and the NOx catalyst are arranged in the collecting path in order from the upstream side,
A bypass path for bypassing the NOx catalyst is branched and connected between a portion where the exhaust path on the most downstream side of the collective path joins with the NOx catalyst, and to the bypass path of the collective path. A path switching member that opens and closes each of the paths is provided on the downstream side of the branch portion and on the inlet side of the bypass path.
Exhaust gas purification device.
The reducing agent supply amount from the reducing agent supply unit is adjusted based on detection information of the NOx detecting means.
The exhaust gas purification apparatus according to claim 1.
Each exhaust path is provided with an opening and closing member for opening and closing it.
The exhaust gas purification apparatus according to claim 1 or 2.
The casing containing the NOx catalyst is equipped with a silencer for attenuating the exhaust sound of the exhaust gas.
The exhaust gas purification apparatus according to claim 1.
The outlet side of the bypass path is connected in communication with the silencer of the casing,
The exhaust gas purification apparatus according to claim 4.
In the casing containing the NOx catalyst, on the upstream side of the NOx catalyst, an air blowing part for ejecting compressed gas from a gas supply source toward the NOx catalyst is provided.
The exhaust gas purifier according to claim 2.
In the casing that houses the NOx catalyst, a slip treatment catalyst that promotes an oxidation treatment of the reducing agent supplied in excess is disposed downstream of the NOx catalyst.
The exhaust gas purifier according to claim 2.
The NOx detection means is configured to detect the amount of power of a generator that generates electricity by driving each engine, and indirectly determine the NOx concentration in the exhaust gas based on the detection result.
The exhaust gas purifier according to claim 2.