JP5856217B2 - Exhaust gas purification system for ships - Google Patents

Description

  The present invention relates to an exhaust gas purification system for removing harmful components in exhaust gas in a ship equipped with 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 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.

JP 2006-341742 A

  By the way, the exhaust gas of a diesel engine contains a large amount of nitrogen oxide, sulfur oxide, particulate matter, and the like in addition to carbon dioxide. These are produced mainly from the combustion mode of diesel engines and heavy oil as 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. Considering the global environment, NOx in the exhaust gas should be removed as much as possible, and it is desired to make NOx harmless by reducing the NOx with a simple structure and efficiency.

  An object of the present invention is to provide an exhaust gas purification system in a ship that has a simple configuration and can efficiently detoxify NOx and render it harmless.

According to the first aspect of the present invention, an aftertreatment device (27) for removing NOx in the exhaust gas from the engine (12) mounted on the ship (1) is provided in the exhaust path (25) of the engine (12). In the exhaust gas purification system provided, the exhaust path (25) of the engine (12) includes a main exhaust path (29) directly communicating with the outside and a branched exhaust path (30) branched from the main exhaust path (29). ), And the post-processing device (27) is disposed downstream of the branch exhaust passage (30), and the main exhaust passage (29) and the branch exhaust passage (30) are connected to the exhaust passages. (29) Open / close members (28a) (28b) for opening and closing the ship (30) are provided, and provided with own ship position detecting means (88) capable of specifying the current position of the own ship, the own ship position detecting means (88) The position of the regulated sea area of exhaust gas and the current position of the ship When the ship position detecting means (88) detects that the ship (1) enters the restricted sea area, the opening / closing member (28b) of the branch exhaust passage (30) is opened. When the opening / closing member (28a) of the main exhaust passage (29) is closed and the ship position detecting means (88) detects that the ship (1) has advanced outside the restricted sea area, The opening and closing members (28a) and (28b) are opened and closed in conjunction with each other so that the opening and closing member (28a) of the main exhaust passage (29) is opened and the opening and closing member (28b) of the branch exhaust passage (30) is closed. And a controller (80) that executes control for causing the engine (12) that is stopped to close at least the opening / closing member (28b) on the branch exhaust passage (30) side . Is.

  According to the present invention, the exhaust passage (25) of the engine (12) is provided with the aftertreatment device (27) for removing NOx in the exhaust gas from the engine (12) mounted on the ship (1). In the exhaust gas purification system, the exhaust path (25) of the engine (12) includes a main exhaust path (29) communicating directly with the outside, and a branch exhaust path (30) branched from the main exhaust path (29). The post-processing device (27) is disposed downstream of the branch exhaust passage (30), and the exhaust passage (29) is provided between the main exhaust passage (29) and the branch exhaust passage (30). ) Open / close members (28a) (28b) for opening and closing (30) are provided, and provided with own ship position detecting means (88) capable of specifying the current position of the own ship, and exhausted by the own ship position detecting means (88). The location of the regulated gas area and the current position of the ship When the ship position detecting means (88) detects that the ship (1) enters the restricted sea area, the opening / closing member (28b) of the branch exhaust passage (30) is opened. When the opening / closing member (28a) of the main exhaust passage (29) is closed and the ship position detecting means (88) detects that the ship (1) has advanced outside the restricted sea area, The opening and closing members (28a) and (28b) are opened and closed in conjunction with each other so that the opening and closing member (28a) of the main exhaust passage (29) is opened and the opening and closing member (28b) of the branch exhaust passage (30) is closed. Since the controller (80) for executing the control is provided, the route through which the exhaust gas passes can be selected automatically and accurately according to the situation such as before entering the regulated sea area or after leaving the regulated sea area. Comply with regulations and consider environmental pollutionMoreover, since the monitoring of whether the ship (1) is outside the regulated sea area or inside the regulated sea area can be omitted, it is highly effective in reducing the burden on seafarers.

  When exhaust gas purification processing is required, the exhaust gas can be reliably guided to the post-treatment device (27). Further, when the purification process is unnecessary, the exhaust gas can be reliably guided to the main exhaust passage (29) side by avoiding the post-treatment device (27), and the state of good exhaust efficiency can be maintained. Accordingly, it is possible to avoid a decrease in the output of each engine (12).

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 post-processing apparatus. It is a functional block diagram which shows the relationship of a controller group. It is a conceptual diagram of the ship in navigation. It is a flowchart which shows an example of switching control. It is a flowchart which shows an example of interruption control.

  Hereinafter, an embodiment embodying the present invention will be described with reference to the drawings 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 hull 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 basically configured to operate efficiently in accordance with the required power amount in the hull 2. For example, all the diesel generators 11 are operated at the time of sailing or the like that consumes a large amount of power, and an arbitrary number of diesel generators 11 are operated at a berth when the power consumption is relatively low.

  The generated power generated by driving each generator 13 is supplied to the electrical system in the hull 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. An engine controller 80 as engine control means is driven by each power generation engine 12 so that the generated power matches the target power set in advance on the generator control panel 14 based on the detection information of the power transducer 15 (details will be described later). Control). The power transducer 15 is also electrically connected to a reduction controller 55 of the 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.

  In the hull 2, a general fuel tank 16a for storing C heavy oil as a general fuel having a high sulfur content and a low sulfur fuel tank 16b for storing A heavy oil as a low sulfur fuel having a low sulfur content are installed. ing. The fuel system of the general fuel tank 16a and the fuel system of the low sulfur fuel tank 16b are configured separately.

  The configurations of these fuel systems are basically the same. Here, the fuel system of the general fuel tank 16a will be described in detail. 2 and 3, components having the same function among the configurations of both fuel systems are denoted by the same reference numerals, and the alphabet "a" is added to the one on the side of the general fuel tank 16a. The letter “b” on the low sulfur fuel tank 16b side is attached.

  The general fuel tank 16a is connected to one supply line 17a. A fuel filter 19a and a fuel flow meter 20a are provided on the upstream side of the supply pipe 17a. The fuel flow meter 20a is electrically connected to a reduction controller 55 of a reducing agent supply device 43 described later. A plurality of feed pipes 21a (three in the embodiment) extend from the supply pipe 17a on the downstream side of the fuel flow meter 20a. Each feed line 21a is connected to the corresponding fuel pump 18 of the power generation engine 12 via a supply switching electromagnetic valve 81 as fuel switching means. The fuel sent to the fuel pump 18 is injected into a combustion chamber (not shown) for each cylinder in the power generation engine 12 by a fuel injection device 83 (see FIG. 6) provided in the power generation engine 12. become. The supply switching electromagnetic valve 81 is electrically connected to an engine controller 80 described later, and is configured to perform a switching operation based on control information from the engine controller 80.

  A return chamber 22a is provided in the middle of each feed line 21a. A return line 23a extending from the fuel injection device 83 to the outside of the power generation engine 12 is connected to a return switching electromagnetic valve 82 via a return chamber 22a, and is connected to the general fuel tank 16a from the return switching electromagnetic valve 82. Unused surplus fuel in the power generation engine 12 is returned to the general fuel tank 16a through the return line 23a. A check valve 24a is provided downstream of the return chamber 22a in the return line 23a. Each return switching electromagnetic valve 82 is electrically connected to an engine controller 80 described later, and is configured to perform switching operation based on control information from the engine controller 80.

  Each supply switching electromagnetic valve 81 is connected not only to the feed line 21a from the general fuel tank 16a but also to the feed line 21b from the low sulfur fuel tank 16b. By the switching operation of the supply switching electromagnetic valve 81, the fuel supplied to the power generation engine 12 is switched between C heavy oil and A heavy oil. Similarly, each return switching electromagnetic valve 82 is connected not only to the return line 23a to the general fuel tank 16a but also to the return line 23b to the low sulfur fuel tank 16b. By the switching operation of the return switching electromagnetic valve 82, the return destination of the surplus fuel from the power generation engine 12 is switched to the general fuel tank 16a or the low sulfur fuel tank 16b.

(4). Next, the intake / exhaust system of the power generator 10 will be described with reference to FIG.

  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.

  The exhaust passage 25 of each power generation engine 12 has a main exhaust passage 29 extending to the funnel 5 and a branch exhaust passage 30 branched from a middle portion of the main exhaust passage 29. As described above, each main exhaust passage 29 extends to the funnel 5 and is configured to communicate directly with the outside. Each of the branch exhaust passages 30 merges into one collective passage 26. A post-processing device 27 that mainly performs exhaust gas purification processing (NOx reduction processing) is provided on the downstream side of the most downstream branch exhaust passage 30 in the collecting passage 26.

  The main exhaust passage 29 and the branch exhaust passage 30 in each exhaust passage 25 are provided with gas-operated on-off valves 28a and 28b as opening and closing members for opening and closing each (three in the embodiment, a total of six). . These on-off valves 28a and 28b 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 addition, as will be described in detail later, the open / close valves 28a and 28b are configured to open and close according to the state of the corresponding power generation engine 12 and the type of fuel used.

  In a state where the second on-off valve 28b is closed and the first on-off valve 28a is opened, the exhaust gas sent from the plurality of power generation engines 12 to the exhaust passages 25 in the exhaust stroke after the expansion stroke is supplied to the main exhaust. It is discharged directly out of the ship 1 via the route 29 (without passing through the post-processing device 27). In a state where the first opening / closing valve 28a is closed and the second opening / closing valve 28b is opened, the exhaust gas is collected in the collecting passage 26 through the branch exhaust passages 30 and is purified through the post-processing device 27. After that, it is discharged out of the ship 1.

  Thus, if the main exhaust passage 29 and the branch exhaust passage 30 in each exhaust passage 25 are provided with the opening / closing valves 28a and 28b as opening and closing members for opening and closing the exhaust passages 29 and 30, for example, in the regulated sea area The path through which the exhaust gas passes is simply switched between the open / close states of both the open / close valves 28a and 28b, when the exhaust gas purification process is necessary and when it is not necessary, such as when navigating and outside the restricted sea area. Can be appropriately selected. Therefore, the exhaust gas can be processed efficiently. For example, when the exhaust gas purification process is unnecessary, the exhaust gas can be guided to the main exhaust passage 29 side directly communicating with the outside by avoiding the post-processing device 27. For this reason, a state with good exhaust efficiency can be maintained, and it becomes possible to avoid a decrease in output of each power generation engine 12. Further, when the exhaust gas purification process is unnecessary, the post-treatment device 27 (NOx catalyst 62 described later) is not exposed to the exhaust gas, which contributes to extending the life of the post-treatment device 27 (NOx catalyst 62 described later). It is.

  The on-off valves 28a and 28b for the power generation engine 12 that is stopped are configured so that at least the second on-off valve 28b on the branch exhaust passage side 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. Of course, the first opening / closing valve 28a may be closed together with the second opening / closing valve 28b.

  As described above, the open / close valves 28a and 28b are of the gas-operated type, and are kept open when there is no gas supply (normally open type). The drive part of each on-off valve 28a, 28b is connected to a gas trunk line 33 extending from the gas supply source 32 via a gas branch line 34. The gas supply source 32 is for supplying air (which may be nitrogen gas) which is a compressed gas for operating the on-off valves 28a and 28b. A gate electromagnetic 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. Each gate electromagnetic valve 35 is electrically connected to an engine controller 80 described later. Each gate electromagnetic valve 35 is configured to open and close based on control information from the engine controller 80, and to supply or stop compressed gas to the drive units of the corresponding open / close valves 28a and 28b. .

  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 in this order from the upstream side between the most downstream gas branch line 34 and the squirting nozzle 37. Is provided. The fusible electromagnetic valve 42 is electrically connected to a reduction controller 55 of a reducing agent supply device 43 described later, and is configured to open and close based on control information from the reduction controller 55.

(5). Next, the structure of the reducing agent supply device 43 will be described with reference to FIGS. 2, 4, and 6.

  The reducing agent supply device 43 mounted on the ship 1 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. ing. 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 injection electromagnetic valve 53, 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 reduction controller 55 described later via the inverter 56. The injection solenoid valve 53 is electrically connected to a reduction controller 55 described later, and is configured to open and close based on control information from the reduction controller 55.

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

  Although not shown in detail, the reduction 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 An output interface is provided.

  As shown in detail in FIG. 6, the reduction controller 55 is electrically connected to the electric motor 54 via the inverter 56, while the exhaust gas temperature in the collective path 26 is adjusted via the temperature controller 57. A temperature sensor 59 as a temperature detecting means for detecting is electrically connected. Further, the reduction 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 that detects a urea water storage amount, and a fumarole electromagnetic valve 42. 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 fusible nozzle 37 described above. 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 does not accumulate in the post-processing device 27 is stored in advance in the ROM or the like of the reduction controller 55, and the same measurement location. 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 reduction controller 55, the compressed gas is sent from the gas supply source 32 to the jet nozzle 37, and the NOx catalyst 62 and The compressed gas is blown toward the slip treatment 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.

  A 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 set upper limit temperature (for example, 305 ° C.) or higher, the injection solenoid valve 53 is opened by a command from the reduction controller 55, and the urea water tank 46 is driven by driving the feed pump 50. The urea water is sent from the urea water injection nozzle 47 to the urea water injection nozzle 47, and the 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 of a float type 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 reduction controller 55 adjusts 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. It is configured. This is because the NOx concentration in the exhaust gas is generally proportional to the total amount of power generated by the 11 groups of diesel generators (which may be the total output (or total load) of the 12 groups of power generation engines). Therefore, the urea water supply amount (reducing agent supply amount) necessary for NOx reduction is approximately proportional to the total power generation amount and, in turn, the NOx concentration in the exhaust gas. Here, although illustration is omitted, the relationship between the urea water supply amount necessary for NOx reduction and the amount of generated power is stored in advance in the reduction controller 55 (for example, ROM) in a map format or a function table format, for example. ing.

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

  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 the NOx concentration in the exhaust gas is indirectly grasped 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.

  In this way, the power transducer 15 as the NOx detecting means detects the total amount of generated power of the generator 13 group, and the NOx concentration in the exhaust gas is indirectly grasped based on the detection result of the power transducer 15. In this case, a sensor dedicated to NOx concentration detection is not required, and the configuration can be simplified to contribute to the reduction of the manufacturing cost.

(6). Structure of Post-Processing Device Next, the structure of the post-processing device 27 will be described with reference to FIGS. 2, 4 and 5.

  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. A slip treatment catalyst 63 that promotes the oxidation treatment of the reducing agent (in this case, ammonia after hydrolysis) and a silencer 64 that attenuates the exhaust noise 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. 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)
4NO + 4NH ₃ + O ₂ → 4N ₂ + 6H ₂ O (reaction at NOx catalyst 62)
6NO ₂ + 8NH ₃ → 7N ₂ + 12H 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.

  In a state where the first opening / closing valve 28a on the main exhaust passage 29 side is closed and the second opening / closing valve 28b on the branch exhaust passage 30 side is opened, the exhaust gas collected in the collecting passage 26 via each branch exhaust passage 30 is Then, it enters the post-treatment casing 61 and passes through the NOx catalyst 62 and the slip treatment catalyst 63 to be purified. 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.

  As described above, in the post-treatment casing 61 that accommodates the NOx catalyst 62, the slip that promotes the oxidation treatment of the reducing agent (ammonia after hydrolysis) supplied excessively downstream from the NOx catalyst 62. Since the treatment catalyst 63 is arranged, surplus reducing agent (ammonia) that passes through the NOx catalyst 62 without being reacted can be rendered harmless by oxidation treatment with nitrogen, and ammonia may remain in the exhaust gas. Can be avoided reliably. 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, since the post-processing casing 61 that accommodates the NOx catalyst 62 is provided with 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 provided as a single unit. The post-processing casing 61 can be packaged, and the downstream side of the exhaust structure can be configured compactly.

(7). Next, the structure of the engine controller 80 as engine control means will be described with reference to FIG.

  The engine controller 80 mounted on the ship 1 mainly controls drive control of each power generation engine 12. Although details are not shown, the engine controller 80 also temporarily stores a ROM for storing a control program and data, a control program and data, in addition to a CPU that executes various arithmetic processes and controls, like the reduction controller 55. RAM, an input / output interface, and the like are provided.

  The engine controller 80 includes the above-described supply switching solenoid valve 81 and each return switching solenoid valve 82, a fuel injection device 83 provided in each fuel pump 18, and a rotational speed detection that detects the rotational speed of each power generation engine 12. An engine rotation sensor 84 as means and an injection amount detection sensor 85 for detecting the fuel injection amount are electrically connected. The engine controller 80 is also electrically connected to a reduction controller 55 of the reducing agent supply device 43, and is configured such that the controllers 55 and 80 exchange control information with each other and execute each control.

  The engine controller 80 is electrically connected to a GPS controller 89 that constitutes ship position detecting means 88 that can identify the current position of the ship 1 (own ship) by radio waves from the artificial satellite 86 and the ground station 87. ing. The own ship position detecting means 88 uses a global positioning system (GPS), for example, similar to that for automobiles, and includes the aforementioned GPS controller 89 and a GPS antenna 90 connected thereto. Yes. The GPS antenna 90 protrudes from the cabin 4 of the ship 1.

  The GPS controller 89 calculates current position information of the ship 1 from radio waves from the artificial satellite 86 or the ground station 87 captured by the GPS antenna 90 (current position information of the artificial satellite 86 or the ground station 87). Like the reduction controller 55 and the engine controller 80, in addition to a CPU that executes various arithmetic processes and controls, a ROM for storing control programs and data, a RAM for temporarily storing control programs and data, and It has an input / output interface.

  The GPS controller 89 stores in advance, as digital map data, regulatory sea area information regarding the regulatory sea area that regulates NOx (nitrogen oxide) and SOx (sulfur oxide) emissions. The map data of such regulated sea area information may cover the information of the entire earth, and if the voyage range is limited, it is limited to that range (for example, only the Pacific Ocean or the east longitude XX to △△ degree range). Also good. Since the regulated sea area may be changed, the map data of the regulated sea area information is preferably updatable.

  The own ship position detecting means 88 is not limited to the one using the GPS, and may be any apparatus capable of grasping the position of the own ship such as a satellite compass. The means for storing the regulated sea area information may be an external storage medium such as an optical disk or a built-in storage medium such as a hard disk. It is also possible to provide a means for storing the regulated sea area information on the engine controller 80 side.

(8). Specific Example of Switching Control Next, an example of switching control in relation to the regulated sea area will be described with reference to the flowcharts of FIGS. 8 and 9. The engine controller 80 according to the embodiment also executes switching control (a general term for opening / closing control of the on-off valve and fuel switching control) for automatically switching the path through which the exhaust gas passes and the fuel to be used in addition to the drive control of each power generation engine 12. It is configured to be possible. Here, it is assumed that the ship 1 is sailing.

  In this case, as shown in the flowchart of FIG. 8, after the current position of the ship 1 is specified by the own ship position detecting means 88, the current position is compared with the map data of the regulated sea area information, and the ship 1 is regulated. Determine whether you are outside the sea area or within the regulated sea area. Needless to say, if the ship 1 is outside the regulated sea area, C heavy oil is used as the fuel, and the exhaust gas is directly discharged to the outside of the ship 1 through each main exhaust passage 29. If the ship 1 is in the regulated sea area, heavy fuel oil A is used as fuel, and the exhaust gas is released to the outside of the ship 1 via each branch exhaust path 30, the collecting path 26, and the aftertreatment device 27. is there.

  When the ship 1 is outside the regulated sea area, the distance from the current position of the ship 1 to the boundary of the regulated sea area is obtained, and then it is determined whether the distance is within a preset target distance. The target distance corresponds to the distance corresponding to the time required for switching the fuel used and is determined from the time required for switching and the navigation speed of the ship 1. Note that the target distance may be set to a variable proportional to the navigation speed (at the high speed, the boundary is reached quickly, so the target distance for preparation needs to be increased).

  When the distance from the ship 1 to the boundary is within the target distance, the first opening / closing valve 28a for the power generation engine 12 being driven is closed by supplying compressed gas based on the driving of the corresponding gate electromagnetic valve 35. At the same time, the second open / close valve 28b is opened by stopping the supply of compressed gas based on the driving of the corresponding gate solenoid valve 35, and the exhaust gas is sent to the post-processing device 27 (the exhaust gas passage is connected to the post-processing device). Switch to 27 side). Further, the switching operation of the supply switching electromagnetic valve 81 causes the fuel pump 18 of the driving power generation engine 12 to communicate with the low sulfur fuel tank 16b to switch the fuel to be used from C heavy oil to A heavy oil. At this time, the return switching electromagnetic valve 82 is also switched to connect the return line 23 to the low sulfur fuel tank 16b.

  Thereafter, when the exhaust gas temperature detected by the temperature sensor 59 becomes equal to or higher than the set upper limit temperature (for example, 305 ° C.), the injection electromagnetic valve 53 is opened, and the urea pump is driven from the urea tank 46 by driving the feed pump 50. The urea water is sent to the nozzle 47, and the urea water is injected into the collecting path 26 from the urea water injection nozzle 47.

  On the contrary, when the ship 1 is in the regulated sea area, after the ship 1 exceeds the border of the regulated sea area, the injection solenoid valve 53 is closed and the drive of the feed pump 50 is stopped to supply urea water. Stop. Then, the first opening / closing valve 28a for the power generation engine 12 being driven is opened by stopping the supply of compressed gas based on the driving of the corresponding gate electromagnetic valve 35, and the second opening / closing valve 28b is corresponding to this. Then, it is closed by the supply of compressed gas based on the driving of the gate electromagnetic valve 35, and the exhaust gas is discharged directly from the main exhaust passage 29 to the outside of the ship 1. In addition, by the switching drive of the supply switching electromagnetic valve 81, the fuel pump 18 of the driving power generation engine 12 and the general fuel tank 16a are connected to switch the fuel to be used from A heavy oil to C heavy oil. At this time, the return switching electromagnetic valve 82 is also switched to connect the return line 23 to the general fuel tank 16a.

  As is apparent from the above description, in the embodiment, the engine controller 80 serving as an engine control unit that controls the driving of each power generation engine 12 is configured to execute the opening / closing control of each opening / closing valve 28a, 28b. Therefore, the open / close state of both the open / close valves 28a and 28b can be automatically switched between when the exhaust gas purification process (NOx reduction process) is required and when it is unnecessary, and the path through which the exhaust gas passes can be easily selected. . Therefore, the exhaust gas can be processed efficiently according to the situation where the ship 1 is placed. In addition, since the opening / closing switching operation of the both opening / closing valves 28a, 28b can be automated, it is effective in reducing the burden on the crew.

  In addition, a temperature sensor 59 is provided as temperature detecting means for detecting the exhaust gas temperature in the collective path 26, and the first open / close valve 28a on the main exhaust path 29 side for each power generation engine 12 being driven is closed and branched. When the exhaust gas temperature detected by the temperature sensor 59 is equal to or higher than the set upper limit temperature in the state in which the second opening / closing valve 28b on the exhaust passage 30 side is opened, the urea water injection nozzle 47 serving as the reducing agent supply unit uses the reducing agent. Since it is configured to supply certain urea water, the exhaust gas is purified using a temperature range (about 305 ° C. or higher) in which NOx reduction proceeds efficiently. For this reason, the NOx reduction effect in the post-processing device 27 can be maintained in a high state. Moreover, since urea water can be used efficiently, it contributes also to suppression of running cost.

  The ship further includes own ship position detecting means 88 that can identify the current position of the ship 1 (own ship), and the own ship position detecting means 88 stores in advance restriction sea area information relating to the restricted sea area of the exhaust gas. The own ship position detecting means 88 specifies the positional relationship between the regulated sea area and the current position of the ship 1 so that the engine controller 80 opens and closes the on-off valves 28a and 28b based on the specified positional relation information. Thus, the route through which the exhaust gas passes can be selected automatically and accurately according to the situation such as before entering the restricted sea area or after leaving the restricted sea area. Therefore, environmental pollution can be considered in compliance with NOx regulations. Further, since monitoring of whether the ship 1 is outside the regulated sea area or inside the regulated sea area can be omitted, it is effective in reducing the burden on seafarers.

  In particular, the engine controller 80 opens the second opening / closing valve 28b on the side of the branch exhaust passage 30 when the ship 1 enters the restricted sea area with respect to the group of both opening / closing valves 28a, 28b for the respective power generation engines 12 being driven. Then, the first on-off valve 28a on the main exhaust passage 29 side is closed, and when the ship 1 moves out of the restricted sea area, the first on-off valve 28a on the main exhaust passage 29 side is opened to open the branch exhaust passage 30 side. Since the second opening / closing valve 28a is controlled to be closed, the exhaust gas can be reliably guided to the post-processing device 27 side when the exhaust gas purification process is required. Further, when the purification process is unnecessary, the exhaust gas can be reliably guided to the main exhaust passage 29 side that communicates directly with the outside, avoiding the post-processing device 27, and the state of good exhaust efficiency can be maintained. Accordingly, it is possible to avoid a decrease in the output of each power generation engine 12.

  Furthermore, the embodiment further includes a supply switching electromagnetic valve 81 as fuel switching means for selectively switching the fuel supply to each power generation engine 12 between A heavy oil and C heavy oil, and the engine controller 80 is configured to supply the supply switching electromagnetic. Since the fuel switching control by the valve 81 is configured to be executed, for example, when using heavy oil A and when using heavy fuel oil C, such as when navigating within the restricted sea area and when navigating outside the restricted sea area, It can be automatically selected by switching driving of the supply switching electromagnetic valve 81. Therefore, it is possible to suppress an increase in fuel cost while dealing with SOx emission regulations and considering environmental pollution. In addition, since the conventional fuel switching operation can be omitted, it is possible to save labor and reduce the burden on the crew.

  Further, the own ship position detecting means 88 specifies the positional relationship between the regulated sea area and the current position of the ship 1, and the engine controller 80 switches the supply switching electromagnetic valve 81 based on the specified positional relation information. Therefore, the fuel to be used can be selected and switched automatically and accurately in accordance with the situation such as before entering the regulated sea area or after leaving the regulated sea area. Therefore, it is possible to reliably contribute to the suppression of environmental pollution by complying with SOx emission regulations.

  In particular, the engine controller 80 according to the embodiment executes the opening / closing control of the both opening / closing valves 28a, 28b and the switching control of the supply switching electromagnetic valve 81 for each power generation engine 12 being driven in conjunction with each other. And it can deal with both SOx emission regulations accurately.

  Now, the engine controller 80 of the embodiment can also execute an interrupt diagnosis process for checking the exhaust gas temperature in the collecting path 26 at appropriate time intervals until the ship 1 is in the restricted sea area and exceeds the boundary. It is configured as follows. Here, it is assumed that the first on-off valve 28a on the main exhaust passage 29 side for each power generation engine 12 being driven is closed, and the second on-off valve 28b on the branch exhaust passage 30 side is open.

  In this case, as shown in the flowchart of FIG. 9, when the exhaust gas temperature detected by the temperature sensor 59 falls below a set lower limit temperature (for example, 300 ° C.), the drive of the feed pump 50 is suppressed to reduce the supply amount of urea water. Or the electromagnetic valve 53 for injection is closed and the drive of the feed pump 50 is stopped, and the supply of urea water is stopped. Next, after reducing the number of power generation engines 12 to be driven, the fuel injection amount to the remaining (driving) power generation engine 12 is increased by the fuel injection device 83 so as to maintain the target power generation amount. As a result, the load on the remaining power generation engine 12 is increased. If the number of power generation engines 12 is originally one, the fuel injection amount to the one power generation engine 12 is increased by the fuel injection device 83 so as to maintain the target power generation amount. . As a result, the exhaust gas temperature toward the post-processing device 27 increases.

  Thereafter, when the exhaust gas temperature becomes equal to or higher than the set upper limit temperature (for example, 305 ° C.), the number of power generation engines 12 that were previously stopped is driven to reduce the number of power generation engines 12 to be driven (original number of drives). The fuel injection device 83 returns the fuel injection amount to each power generation engine 12 to an amount commensurate with the target power generation amount supply. Then, by driving the feed pump 50, the urea water supply amount is returned to the state before the exhaust gas temperature is lowered, or the injection electromagnetic valve 53 is opened and the feed pump 50 is driven to restart the supply of urea water. is there.

  As is clear from the above description, in the embodiment, the first on-off valve 28a on the main exhaust passage 29 side is closed and the second on-off valve 28b on the branch exhaust passage 30 side is opened for each power generation engine 12 being driven. In this state, when the exhaust gas temperature detected by the temperature sensor 59 becomes equal to or lower than the set lower limit temperature, the number of the power generating engines 12 is reduced, and the remaining power is being maintained so as to maintain the target power generation amount. ) Is increased in the fuel injection device 83 by the fuel injection device 83, so that the NOx reduction hardly progresses but the NOx generation amount itself is low (about 300 ° C. or less). Even in this case, the exhaust gas temperature can be forcibly increased to a temperature range (about 305 ° C. or higher) in which NOx reduction proceeds efficiently. Therefore, NOx reduction in the post-treatment device 27 can be maintained in a highly efficient state, and the reliability of the exhaust gas purification process is improved.

  In the embodiment, as described above, the phrase “reducing the number of driving engines 12 for power generation” means “maintaining the driving of one unit if the original number of driving units is only one”. It is added that it is used including.

  Further, when the exhaust gas temperature becomes equal to or lower than the set lower limit temperature, the supply of the reducing agent (urea water) is reduced or stopped from the urea water injection nozzle 47 as the reducing agent supply unit. In the low temperature range (about 300 ° C. or less), the exhaust gas purification process is not actively performed. For this reason, a possibility that a reducing agent may adhere and remain on the upstream side of the aftertreatment device 27 (NOx catalyst 62) can be reduced. In particular, as in the embodiment, if the reducing agent is urea water, the possibility that solid urea after moisture evaporation will adhere to or remain on the upstream side of the post-treatment device 27 (NOx catalyst 62) is reduced, and urea hydrolysis is performed. The harm caused by ammonium sulfate produced by the reaction between ammonia and sulfur content generated in the above can also be suppressed. Furthermore, the reducing agent (urea water) can be used more efficiently, which contributes to further suppression of running costs.

  Further, when the exhaust gas temperature becomes equal to or higher than the set upper limit temperature, the previously stopped power generation engine 12 is driven and returned to the number before the number of power generation engines 12 is reduced (original drive number). Since the fuel injection amount to each power generation engine 12 is configured to return to an amount commensurate with the target power generation power supply, if the exhaust gas temperature exceeds the set upper limit temperature, each power generation engine 12 Excessive load is not applied, and deterioration of fuel consumption due to forced increase in exhaust gas temperature can be minimized.

  In addition, when returning the number of driving engines 12 for power generation to the number before the reduction (original driving number) and returning the fuel injection amount to each power generation engine 12 to an amount corresponding to the target power generation amount supply, Since it is configured to return the urea water supply to the original amount before the exhaust gas temperature drops or restart the urea water supply, the supply and stop of the urea water can be switched smoothly, depending on the exhaust gas temperature Thus, the exhaust gas purification process can be executed efficiently. In the interrupt diagnosis process shown in FIG. 9, the urea water supply control may be omitted, and only the number of power generation engines driven and the fuel injection amount control may be executed.

  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.

DESCRIPTION OF SYMBOLS 1 Ship 10 Power generator 11 Diesel generator 12 Diesel engine 13 Power generator 15 Power transducer 25 Exhaust path 26 Collecting path 27 Post-processing apparatus 28a, 28b Open / close valve 29 Main exhaust path 30 Branch exhaust path 35 Gate solenoid valve 43 Reducing agent Supply device 55 Reduction controller 59 Temperature sensor 62 NOx catalyst 80 Engine controller 81 Supply switching electromagnetic valve 82 Return switching electromagnetic valve 83 Fuel injection device 84 Engine rotation sensor 88 Own ship position detection means 89 GPS controller 90 GPS antenna

Claims (1)

An exhaust gas purification system provided with an aftertreatment device (27) for removing NOx in exhaust gas from an engine (12) mounted on a ship (1) in an exhaust path (25) of the engine (12). In
The exhaust path (25) of the engine (12) includes a main exhaust path (29) communicating directly with the outside and a branch exhaust path (30) branched from the main exhaust path (29), and the branch exhaust path The post-treatment device (27) is disposed downstream of (30), and the exhaust passages (29) and (30) are opened and closed between the main exhaust passage (29) and the branch exhaust passage (30). Opening and closing members (28a) (28b) for providing
Own ship position detecting means (88) capable of specifying the current position of the own ship, wherein the own ship position detecting means (88) specifies the positional relationship between the restricted sea area of the exhaust gas and the current position of the own ship;
When the ship position detecting means (88) detects that the ship (1) enters the restricted sea area, the main exhaust is opened by opening the opening / closing member (28b) of the branch exhaust passage (30). When the opening / closing member (28a) of the road (29) is closed and the ship position detecting means (88) detects that the ship (1) has advanced out of the restricted sea area, the main exhaust path (29 The opening / closing member (28a) is opened and the opening / closing member (28b) of the branch exhaust passage (30) is closed so that the both opening / closing members (28a) (28b) are opened and closed in conjunction with each other. A controller (80) ,
For the stopped engine (12), at least the opening / closing member (28b) on the branch exhaust passage (30) side is closed,
Exhaust gas purification system for ships.

Images