JP2013224150A - Engine exhaust gas purification system in ship - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make compatible economical efficiency and regulation clearance while saving power, in a ship which comes in and goes out of a sea area in which NOx regulation is applied.SOLUTION: An engine exhaust gas purification system in a ship is mounted with an engine 1 switchable in a purification state of an exhaust gas, and an own-ship position automatic detection means B which can automatically specify a present place, and the own-ship position automatic detection means B operates to specify a positional relationship between a boundary of an exhaust-gas regulation objective sea area and an own ship on the basis of electric waves transmitted from a satellite or an earth station, or from both of them. An exhaust system of the engine 1 comprises a main exhaust pipe 8 connected with a NOx exhaust treatment device 9 of a reducer adding system, and a bypass exhaust pipe 16 which exhausts an exhaust gas without making it pass through the NOx exhaust treatment device 9. When the own ship is within the regulation objective sea area, the bypass exhaust pipe 16 is closed, and a reducer is added to the NOx exhaust treatment device 9, and when the own ship is out of the regulation objective sea area, the exhaust gas is made to flow to the bypass exhaust pipe 16, and the reducer is not added to the NOx exhaust treatment device 9.

Description

  TECHNICAL FIELD The present invention relates to an exhaust gas purification system for an engine (diesel engine) in a ship, and more particularly to an exhaust gas purification system for a ship entering and exiting a sea area where the amount of exhaust gas emission is regulated. is there.

  Ships are generally equipped with diesel engines, but NOx (nitrogen oxides) contained in exhaust gas is required to be purified like land vehicles. Further, since marine diesel engines use heavy oil as fuel, SOx (sulfur participant) is often contained in the exhaust gas. Therefore, purification of SOx is also required.

  As a means for purifying NOx (nitrogen participant), an SCR catalyst purification method using urea as a reducing agent has become common. In this SCR catalyst purification method, in general, a honeycomb structure made of a material in which an active component such as V or Cr is supported on an oxide carrier such as Ti is used, and an aqueous reducing agent solution is provided upstream of the honeycomb structure. When the urea water is sprayed, the urea water is hydrolyzed by the heat of the exhaust gas to generate ammonia. This ammonia acts on NOx as a reducing agent, and NOx is decomposed into harmless nitrogen and water.

  On the other hand, C heavy oil is often used as a general fuel for ships, but C heavy oil has a high sulfur content. Therefore, as a countermeasure against SOx, A heavy oil with low sulfur content is used. It is dealt with by using. Regardless of the high seas and territorial seas, it is preferable to regulate the environment uniformly regardless of the high seas or territorial seas, but the SOx purification technology has not yet been established, and the use of A heavy oil is obligatory in terms of operating costs and effective use of heavy oil There is an actual situation that there is a problem, and as a harmonization measure, at present, a regulated sea area is defined for SOx.

  Therefore, ships entering and leaving the regulated sea area are equipped with C heavy oil with a high sulfur content and A heavy oil with a low sulfur content as fuel, and the fuel to be used according to the access to the regulated sea area. Will be switched. Patent Document 1 discloses a device that uses heavy oil A, which has high fluidity at the beginning of operation, and switches the engine to warm C heavy oil to a certain extent. As disclosed in Document 1, a switching device is installed, and an operator (for example, an engineer) manually switches the fuel to be used.

JP 2002-227676 A

  Now, current ships are equipped with GPS (Global Positioning System: Global Positioning System) and own ship position automatic detection means using a satellite compass, and electronic charts using these own ship position automatic detection means. Can accurately grasp the position of the ship. However, the boundaries of the regulated sea areas are artificially determined, which must be known in advance as information.For example, the regulation within the coastal XX nautical miles accurately grasps the coastline. Otherwise, there is a situation that the boundary of the regulated sea area cannot be accurately understood, and there is a problem that the response by human hand is not accurate and quick. Of course, the burden on the operator is large (the burden is heavy because it is sometimes nighttime or stormy to pass through regulated sea areas).

  In addition, when a SCR reduction catalyst for NOx purification and a cleaning dust collector for removing particulate matter are added as a purification device that acts directly on exhaust gas, these are also activated or activated in response to fuel switching. However, the conventional manual method lacks accuracy, certainty, and quickness, and may not comply with regulations or waste expensive fuel.

  The present invention has been made to improve the current situation.

  The engine exhaust gas purification system for a ship according to the invention of claim 1 is equipped with an engine (1) capable of switching the exhaust gas purification state and own ship position automatic detection means (B) capable of automatically specifying the present location. The own ship position automatic detection means (B) operates to identify the positional relationship between the boundary of the sea area subject to exhaust gas regulation and the own ship based on radio waves transmitted from a satellite or a ground station or both. The exhaust system of the engine (1) is connected to a main exhaust pipe (8) to which a reducing agent addition type NOx exhaust treatment device (9) is connected, and exhaust gas is passed through the NOx exhaust treatment device (9). And the bypass exhaust pipe (16) that discharges without being discharged, and when the ship is in the regulated sea area, the bypass exhaust pipe (16) is closed and the NOx exhaust treatment device (9) is supplied with a reducing agent. Add and regulate by own ship If that is outside elephant waters, it is that by passing the exhaust gas in the bypass exhaust pipe (16) is configured not to add the reducing agent to the NOx exhaust treatment apparatus (9).

  According to a second aspect of the present invention, in the engine exhaust gas purification system according to the first aspect, the ship position automatic detection means (B) is incorporated in the control device (41) for switching the exhaust gas purification state. It is that.

  In the present invention, when a ship enters or exits an exhaust gas restricted area, the positional relationship between the boundary of the restricted area and the ship is automatically determined. It can be controlled to automatically switch to a cleared state and automatically switch to a state in which the regulated clear state is released when exiting from the regulated sea area. Therefore, the regulations regarding ship exhaust gas can be cleared accurately and quickly, and the labor of the crew can be saved, thereby contributing to labor saving and reduction of burden.

  For NOx purification, a reduction catalyst that adds a reducing agent such as urea is used. However, when the invention of claim 1 is adopted, if the ship is outside the regulated sea area, the exhaust gas is bypassed and discharged. By doing so, the usage amount of the reducing agent can be suppressed to reduce the operation cost, and the loss of output due to the resistance caused by the exhaust gas passing through the catalyst can be prevented.

  Specifically, the own ship position automatic detection means can use a GPS position specifying system or a satellite compass, but if the own ship position automatic detection means is incorporated in the control device of the purification system as in claim 2, the signal Since the transmission system is simplified, there is an advantage that the certainty of operation is higher.

It is a typical block diagram which shows embodiment of this invention. It is sectional drawing which shows an example of an exhaust gas switching valve. It is a conceptual diagram of the ship in navigation. It is a flowchart which shows the example of control.

  Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a conceptual block diagram showing equipment / devices related to the present invention, FIG. 2 is a diagram showing a specific structure of the device, and FIG. 3 is a conceptual diagram of a ship in operation. First, the arrangement of facilities / devices will be described.

(1) Basic configuration around the engine As shown in FIG. 1, the ship includes a diesel engine 1, and a generator 2 is connected to the engine 1. Fuel is supplied to the engine 1 from either the general fuel tank 3 or the low sulfur fuel tank 4. In FIG. 1, for the sake of simplicity of explanation, a state in which a switching valve 6 is interposed in the fuel line 5 that connects both the fuel tanks 3 and 4 and the engine 1 is illustrated. It can be said that it is common to connect fuel injection system pipes to 4 and selectively use any one of the fuel injection system pipes. As in the past, an example of general fuel is C heavy oil, and low sulfur fuel is A heavy oil.

  The generator of the present embodiment is mainly for driving a marine propulsion motor, but the engine 1 can also drive the screw directly. Of course, the generator 2 may be connected to the engine 1 as a dedicated engine for obtaining electric power to be used in the ship. An output sensor 7 is attached to the generator 2. The output sensor 7 directly detects the output (or load) of the generator, but the output of the engine 1 and the output of the generator 2 are almost the same, so the output sensor 7 functions as an output detection means of the engine 1. ing.

  The engine 1 has a main exhaust pipe 8 connected to an exhaust manifold, and an NOx exhaust treatment device 9 is connected to the main exhaust pipe 8. The NOx exhaust treatment device 9 includes an SCR reduction catalyst 10, a slip catalyst 11 for treating NOx that has passed through the SCR reduction catalyst 10, and a silencer 12 in order from the upstream side when viewed from the flow direction of the exhaust gas. have. A discharge pipe 13 is connected to the silencer 12. Note that the discharge pipe 13 can also be considered as a part of the main exhaust pipe 8. In this case, the exhaust treatment device 9 is interposed in the middle of the main exhaust pipe 8. For convenience, the upstream side portion of the exhaust treatment device 9 is defined as the main exhaust pipe 8.

  A spray port 15 for spraying urea water as an example of the reducing agent aqueous solution is provided in the middle of the main exhaust pipe 8. In addition, a blower 14 that ejects air toward the SCR reduction catalyst 10 is connected to the exhaust treatment device 9. A bypass exhaust pipe 16 is connected upstream of the spray port 15 in the main exhaust pipe 8, and the end of the bypass exhaust pipe 16 is connected to the silencer 12 portion of the exhaust treatment device 8. Yes.

  Although omitted in the drawing, it is also possible to connect a cleaning dust collecting device for repairing particulate matter to the downstream side of the exhaust treatment device 9. Alternatively, an afterburner can be connected.

  A switching valve 17 for changing the flow direction of the exhaust gas is provided at a connection portion between the exhaust switching valve 17 and the bypass exhaust pipe 16. A specific structural example of the switching valve 17 is shown in FIG. That is, in this example, the switching valve 17 is of a flat plate type and rotates around a support shaft located at one end thereof, and when rotated by an actuator 18 such as a motor, the inlet of the bypass exhaust pipe 16 is provided. Are switched to a posture for closing the main exhaust pipe 8 and a posture for closing the main exhaust pipe 8.

(2). Urea water supply system The ship has a water generator 21 that pumps seawater into the fresh water by the first pump 20 and a water tank 22 that stores fresh water produced by the water generator 21. doing. The water tank 22 is connected with a number of general water pipes 23 for supplying water to a kitchen or a washroom. The ship further includes a raw material hopper 24 for charging granular urea as an example of a raw material reducing agent for NOx purification, a mixing tank 25 for mixing the raw material urea supplied from the raw material hopper 24 with water to form urea water, An adjustment tank 26 for adjusting the concentration of urea water produced in the mixing tank 25 is mounted.

  The mixing tank 25 and the water tank 22 are connected by a raw water pipe 27, and the raw material pipe 27 is provided with a second pump 28 for turning on / off water supply. The first aqueous solution pipe 29 is connected, and a third pump 30 is interposed in the first aqueous solution pipe 29. The adjustment tank 26 and the spray port 15 are connected by a second aqueous solution pipe 31, and an electromagnetic type spray opening / closing valve 32 is interposed in the second aqueous solution pipe 31.

  The raw material hopper 24 is provided with a drying device 34, and the discharge pipe 36 between the raw material hopper 24 and the mixing tank 25 is provided with shutter means 37 for opening and closing the discharge pipe 36. The raw material hopper 24 is provided with a capacity sensor 35 that detects the amount of raw material urea. The shutter means 36 is remotely driven by an actuator such as an electromagnetic solenoid. The mixing tank 25 is provided with a rotary stirring device 38, a water level sensor 39, and a heating means 40. The stirring device 38 is driven by a motor.

  The adjustment tank 26 is also provided with a stirring device 41, a heating means 42, and a water level sensor 43. The adjustment tank 26 and the water tank 22 are connected by a dilution water pipe 44, and a third pump 45 is interposed in the dilution water pipe 44. Further, the adjustment tank 26 is provided with a concentration sensor 46 for detecting the urea concentration of the urea water. A water level sensor 47 is also provided in the water tank 22, and the first pump 20 automatically operates when the water level falls to the lower limit, and the first pump 20 automatically stops when the water level rises to the upper limit.

(3). Configuration of Control System In this embodiment, a control device 41 having a central processing unit (CPU), a memory and the like is provided as a central device of the exhaust gas purification system. The control device 41 can be manufactured and arranged as a dedicated product, or a commercially available personal computer or workstation can be used.

  A predetermined program is incorporated in the control device 41, and signals are input and output based on input signals. For example, signals are input to the control device 41 from the capacity sensor 35 of the raw material hopper 24, the water level sensor 35 of the mixing tank 25, the water level sensor 39 of the adjustment tank 26, and the output sensor 7 of the generator 1. The two fuel tanks 3 and 4 are also provided with capacity sensors (level meters) 42 and 43, and signals are sent from these capacity sensors 42 and 43 to the control device 41. Although not shown, the fuel switching valve 6 and the exhaust switching valve 17 are also provided with sensors for detecting the open state, and signals from these sensors are sent to the control device 41.

  Further, the ship is equipped with an antenna A that receives radio waves from satellites and ground stations, and own ship position automatic detection means B that identifies the ship position based on the radio waves received by the antenna A. A control signal is also sent from the automatic detection means B to the control device 41. The own ship position automatic detection means B is considered as a part of the control device 41.

  The controller 41 controls the drive of the following. That is, the stirring means 28 and 41 and the heating means 40 and 42 of the second pump 28, the mixing tank 25 and the adjustment tank 26, the shutter means 37, the fourth pump 45 of the dilution water pipe 44, and the spray of the second aqueous solution pipe 31. The driving of the on-off valve 32, the fuel switching valve 6, the exhaust switching valve 17, and the blower 14 is controlled.

  If the concentration of NOx in the exhaust gas is high, the amount of urea necessary for the unit amount of the exhaust gas also increases. Therefore, in the mixing tank 25, an aqueous solution having a urea concentration corresponding to the highest possible NOx concentration is manufactured, and based on the signal from the output sensor 7, the urea water has a urea concentration necessary for purification. The fourth pump 45 is driven to take in the dilution water. When the predetermined concentration is reached, the driving of the fourth pump 45 is stopped. When it is necessary to increase the concentration of urea water, the third pump 30 is driven to take in high-concentration urea water.

  The concentration of NOx and the concentration of urea water can be a fine adjustment system that adjusts the urea concentration sensitively in response to slight changes in the concentration of NOx. While dividing into multiple zones such as medium output and high output, urea concentration is also divided into multiple concentration areas such as low concentration, medium concentration and high concentration corresponding to the output zone to change the output zone It can be said that the zone adjustment method of changing the density area in accordance with this is realistic. The exhaust system is also provided with a temperature sensor, and cool air is sent from the blower 14 when the temperature of the exhaust gas rises excessively.

  In a memory provided in the control device 41, information (regulation map) indicating what kind of exhaust gas regulation is performed in which sea area is stored as digital data. This information may cover information on the entire earth, or may be limited to the range (for example, only the Pacific Ocean or the east longitude XX to ΔΔ degree range) when the navigation range is limited. Since the contents of regulation may be changed, it is preferable that the regulation map data can be updated. The restriction map memory may be an external medium type such as a CD or a built-in type such as a hard disk.

(4). Specific Example of Control Next, based on the control flow of FIG. 4, an example of control in relation to the regulated sea area will be described. The flow of FIG. 4 shows a case where the regulated sea area is entered from the regulated sea area. First, when the system is started up, the position of the ship is specified as two-dimensional data of latitude and longitude by the ship position automatic detection means. Next, the own ship position and the restriction map are collated (compared) to determine whether they are outside or inside the restricted sea area. If it is within the regulated sea area, it is determined whether to check the fuel to be used. However, since this embodiment is premised on the outside of the regulated sea area, the description is omitted.

  When the ship is outside the restricted sea area, whether or not the fuel uses general fuel, whether or not the exhaust gas passes through the main exhaust pipe 8 instead of the bypass exhaust pipe 16, and the spray of urea water It is confirmed whether or not. Whether or not general fuel is used is determined by a signal from a sensor provided in the fuel switching valve 6, and whether or not the exhaust gas passes through the main exhaust pipe 8 is actuated by opening and closing the exhaust switching valve 17. It is judged by a signal from the sensor, and whether or not urea water is sprayed is judged by a signal from a sensor provided in the spray modification valve 32.

  When the general fuel is not used, the exhaust gas does not pass through the main exhaust pipe 8, or the urea water is not sprayed, a warning is given as an abnormal state, respectively, and the system stops until the countermeasure is completed. When general fuel is used and the purification device 9 operates normally and NOx is removed, the ship's position is compared with the regulated sea area boundary position, and the reach distance to the regulated sea area is calculated. Then, it is determined whether the distance is within or outside a target distance that is predetermined as a distance (to be precise, time) required for switching the purification system. The target distance is determined based on the time required for switching and the navigation speed. It is also possible to set the target distance to a variable that is proportional to the navigation speed (the high speed will reach the boundary early, so the target distance for preparation needs to be long).

  When the distance to the regulated sea area is greater than the target distance, no special measures are taken and the system is suspended. When a predetermined time elapses, it is determined whether the target distance is inside or outside. When the distance to the regulated sea area becomes smaller than the target distance, preparations are made for fuel switching and urea water spray stop switching. As preparation, for example, an alarm is issued, and a sailor is taken to take an action that requires manual work.

  When a predetermined time has elapsed from the switching preparation process, it is determined whether or not the switching preparation is completed. Completion of the switching preparation is performed, for example, when a crew member in charge issues a signal by operating a button. If the switch ready button is pressed before the predetermined time has elapsed, the step of determining whether the switch is ready is passed and the process proceeds to the next.

  After entering the target distance, the distance to the regulated sea area is calculated in a short time interval or in real time, and the switching arrival position (for example, a position one to several nautical miles before the boundary between the regulated sea area and the non-regulated sea area) ), The purification device switching such as the fuel switching is automatically performed.

  In this embodiment, when the fuel is switched to heavy fuel oil A, the exhaust gas flows into the bypass exhaust pipe 16 and the spraying of urea water is stopped. Of course, it is also possible to continue the purification of NOx by switching only the fuel and allowing the exhaust gas to pass through the main exhaust pipe 8.

  When the system change such as fuel switching is completed, the end of switching is reported by a signal from a sensor provided in the fuel switching valve 6 and the system ends. When the switching completion signal is not received, a warning is issued in a state where the trouble is clearly indicated, and the cause of the trouble is removed manually.

  The above explanation showed the control when entering from the non-regulated sea area to the regulated sea area, but when going out from the regulated sea area to the non-regulated sea area, the basic flow is simply reversed. Is the same as above. In addition, the above explanation has been given for different systems depending on whether entering or leaving the regulated sea area, but in actuality, if the ship's position is specified, whether it is inside or outside the regulated sea area. It can be said that the system is largely branched into two based on the determination result.

(5). Others The present invention can be embodied in various ways other than the above embodiment. For example, what kind of exhaust gas measures to switch to in what scene can be changed based on the installed equipment / equipment and the contents of regulations. For example, a cleaning dust collector for collecting particulate matter can be used. When equipped, it is possible to operate the cleaning dust collector in accordance with the approach to the regulated sea area. When a purification device that works on exhaust gas is provided, such as a catalytic purification device or a cleaning dust collection device, it is possible to vary the purification ability inside and outside the regulated sea area.

  Furthermore, when three or more types of fuel are installed, they can be used properly according to the level of regulation content, or when multiple types of fuel can be mixed and supplied to the engine, they are mixed according to the entry and exit of the regulated sea area. It is also possible to change the ratio.

A antenna B own ship position automatic detection means 1 engine 2 generator 3 general fuel tank 4 low sulfur fuel tank 6 fuel switching valve 8 main exhaust pipe 9 exhaust treatment device 10 SCR reduction catalyst 11 for NOx purification 11 slip catalyst 12 silencer 15 Urea water spray port 16 Bypass exhaust pipe 17 Exhaust gas switching valve 25 Mixing tank for urea water production 26 Urea water concentration adjusting tank 41 Control device

Claims (2)

The engine (1) that can switch the purification state of exhaust gas and the own ship position automatic detection means (B) that can automatically identify the current location are installed. The own ship position automatic detection means (B) can be a satellite or a ground While operating to identify the positional relationship between the boundary of the sea area subject to exhaust gas regulation and own ship based on radio waves transmitted from the station or both,
The exhaust system of the engine (1) includes a main exhaust pipe (8) to which a reducing agent addition type NOx exhaust treatment device (9) is connected, and does not allow exhaust gas to pass through the NOx exhaust treatment device (9). A bypass exhaust pipe (16) for discharging to
When the ship is in the restricted sea area, the bypass exhaust pipe (16) is closed and a reducing agent is added to the NOx exhaust treatment device (9), and the ship is outside the restricted sea area. The exhaust gas is caused to flow through the bypass exhaust pipe (16) so that no reducing agent is added to the NOx exhaust treatment device (9).
Engine exhaust gas purification system for ships. The own ship position automatic detection means (B) is incorporated in the control device (41) for switching the purification state of the exhaust gas,
The exhaust gas purification system of the engine in the ship described in Claim 1.

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