KR102467963B1 - Scavenge Air Cooling System and Method for Ship - Google Patents

Abstract

The present invention relates to a system and method for cooling combustion air of a ship's engine according to the principle that engine efficiency is improved when the air temperature required for fuel combustion in a ship's engine is low.
A marine engine combustion air cooling system according to the present invention includes a combustion air cooler for cooling combustion air of an engine; a first cooler for cooling the cooling water discharged after cooling the combustion air in the combustion air cooler using a first refrigerant; and a second cooler for cooling the cooling water discharged after cooling the combustion air in the combustion air cooler using a second refrigerant, wherein the second refrigerant is BOG supplied through the BOG supply line, and In the second cooler, the cooling water, in which the cooling water and the BOG exchange heat, cools the combustion air of the engine while circulating through at least one of the flow paths passing through the first cooler or the second cooler.

Description

Combustion air cooling system and method for marine engines {Scavenge Air Cooling System and Method for Ship}

The present invention relates to a system and method for cooling combustion air of a ship's engine according to the principle that engine efficiency is improved when the air temperature required for fuel combustion in a ship's engine is low.

Ships are provided with a main engine and a generator engine. These engines can improve cold corrosion inside the cylinder as combustion air at a certain level of low temperature is supplied into the cylinder. By reducing SFOC (Specific Fuel Oil Consumption), fuel costs can be reduced and engine efficiency can be improved.

To this end, conventionally, a central fresh water cooling system for cooling and circulating fresh water used in ships is provided, and combustion air is cooled using fresh water cooled in the central cooling system.

The central fresh water cooling system usually provides a cooling fresh water pump that circulates fresh water, a cooling seawater pump that cools fresh water by sucking sea water, and a heat exchanger that exchanges heat between fresh water and sea water, thereby exchanging heat. Based on the machine, it is largely divided into two cooling circuits.

In this central fresh water cooling system, the temperature of the cooled fresh water is designed to be about 36 ° C, and the temperature of the engine combustion air is determined by heat exchange with the fresh water temperature. The temperature can be lowered further, and the cooling temperature of the fresh water is determined by the temperature and heat exchange amount of the seawater that cools the fresh water. Since fresh water is also supplied to other consumers, it is inefficient to lower the fresh water cooling design temperature of the entire cooling system.

That is, in the case of a ship or offshore structure operating in a place with high seawater temperature or floating on the sea with high seawater temperature, there is a limit to lowering the temperature of fresh water cooled by the central fresh water cooling system and the temperature of engine combustion air. For this purpose, providing a separate cooling water system for cooling combustion air in a special limited space called a ship is disadvantageous in terms of space and cost, so it is not preferred.

Therefore, the present invention has been made to improve the problems of the prior art as described above, while minimizing design changes of the existing in-ship central fresh water cooling system, while cooling the combustion air of the engine to a lower temperature even if the temperature of the sea water is high. It is intended to provide a marine engine combustion air cooling system and method that can reduce fuel costs and improve engine efficiency.

According to one aspect of the present invention for achieving the above object, a combustion air cooler for cooling combustion air of an engine; a first cooler for cooling the cooling water discharged after cooling the combustion air in the combustion air cooler using a first refrigerant; and a second cooler for cooling the cooling water discharged after cooling the combustion air in the combustion air cooler using a second refrigerant, wherein the second refrigerant is BOG supplied through the BOG supply line, and In the second cooler, the cooling water and the BOG exchange heat, and the cooling water cools the combustion air of the engine while circulating through at least one of the flow paths passing through the first cooler or the second cooler. Marine engine combustion, characterized in that An air cooling system is provided.

Preferably, a first circulation line in which the first cooler is provided; And a second circulation line in which the second cooler is provided, and in the first circulation line, a number of cooling water cooled by the first refrigerant in the first cooler are supplied to the combustion air cooler and fresh water demand. Of the fresh water pump; may be provided.

Preferably, the second circulation line is provided with a circulation pump for circulating the cooling water discharged from the combustion air cooler to the second cooler, and the second circulation line is connected to the plurality of the plurality of combustion air coolers from the rear end of the combustion air cooler. Is connected to the rear end of the fresh water pump, when the circulation pump is operated, the operation of at least one of the fresh water pump can be stopped.

Preferably, the second circulation line is provided with a boosting pump supplying the cooling water discharged from the combustion air cooler to the second cooler, and the second circulation line is provided from a rear end of the combustion air cooler to the plurality of cooling water. Connected to the front end of the fresh water pump, when the boosting pump is operated, it is possible to reduce the operating load of at least one of the fresh water pumps.

Preferably, a first switching valve provided at a rear end of the combustion air cooler to control a flow path so that the cooling water flows into the first circulation line or the second circulation line; and a second switching valve provided at a front end of the combustion air cooler, wherein the first switching valve switches a flow path so that the cooling water discharged from the combustion air cooler is supplied to the first cooler or the second cooler. , The second switching valve is provided with a marine engine combustion air cooling system for switching a flow path so that the cooling water cooled in the first cooler or the cooling water cooled in the second cooler is supplied to the combustion air cooler.

Preferably, the second switching valve may switch the flow path so that the fresh water pump sucks the cooling water cooled in the second cooler or the cooling water cooled in the first cooler.

According to another aspect of the present invention for achieving the above object, cooling the cooling water in the first cooler; cooling engine combustion air by pumping the cooled cooling water; and selecting a first cooling mode for circulating the cooling water after cooling the engine combustion air to the first cooler or a second cooling mode for circulating the cooling water to the second cooler. A method is provided.

Preferably, in the first cooler, the cooling water after cooling the engine combustion air is cooled using seawater, and in the second cooler, the cooling water after cooling the engine combustion air is cooled using BOG.

Preferably, supplying at least a portion of the pumped cooling water to a fresh water consumer; and recovering the fresh water after being supplied to the fresh water consumer and circulating it to the first cooler.

Preferably, the first cooling mode operates at least two first pumps, at least two first coolers and at least two fresh water pumps, and the second cooling mode is at least one more than the first cooling mode. The first pump and at least one first cooler may be operated less.

Preferably, the second cooling mode may operate less than at least one fresh water pump than the first cooling mode.

Preferably, the second cooling mode can lower the operating load of at least one seawater pump and at least one fresh water pump than the first cooling mode.

Preferably, controlling the opening direction of the first switching valve to cool the combustion air and then switching the flow path of the discharged cooling water; and controlling an opening direction of a second switching valve to switch a flow path of cooling water cooled by the first cooler or the second cooler and supplied to cool the combustion air. 2 Can switch to cooling mode.

According to the marine engine combustion air cooling system and method according to the present invention, the combustion air of the engine can be cooled to the minimum temperature for improving the combustion efficiency of the engine, thereby improving engine efficiency and reducing fuel consumption. In addition, it is possible to improve the cylinder internal condition by improving the cylinder corrosion of the engine.

In addition, it can be operated with minimal design changes of the conventional central fresh water cooling system, and the combination of the number of operating fresh water pumps, capacity and load can be optimized for each operation mode to save energy. savings can be made

In addition, it is possible to independently control the temperature of cooling water supplied to cool engine combustion air and the temperature of fresh water supplied to other sources of fresh water within the ship, thereby reducing operational load and saving energy.

In addition, the internal pressure of the liquefied gas storage tank of the ship can be adjusted, and waste of liquefied gas can be reduced.

1 is a block diagram schematically showing a system for cooling combustion air of a marine engine according to a first embodiment of the present invention.
FIG. 2 is a schematic configuration diagram of a marine engine combustion air cooling system according to a second embodiment of the present invention.
3 is a configuration diagram schematically illustrating a cooling system for cooling engine combustion air for a marine engine according to a third embodiment of the present invention.

In order to fully understand the operational advantages of the present invention and the objects achieved by the practice of the present invention, reference should be made to the accompanying drawings illustrating preferred embodiments of the present invention and the contents described in the accompanying drawings.

Hereinafter, the configuration and operation of a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. In adding reference numerals to the components of each drawing, it should be noted that the same components are marked with the same numerals as much as possible, even if they are displayed on different drawings. In addition, the following examples may be modified in many different forms, and the scope of the present invention is not limited to the following examples.

Hereinafter, in the present specification, fresh water as the term implies, that is, fresh water purified by desalination of seawater may refer to fresh water supplied to a customer as water necessary for a process in a ship or process water, and may refer to a device or intermediate It may refer to cooling water supplied to cool a medium, but in order to describe the embodiments according to the present invention, even if it is described as cooling water for convenience, it is always cooling water supplied for the purpose of cooling a device or medium. Not limiting. Hereinafter, in an embodiment of the present invention to be described, fresh water supplied to cool engine combustion air is referred to as 'cooling water' to distinguish terms, and fresh water supplied to other demand sources other than cooling water of engine combustion air is referred to as 'cooling water'. It will be referred to as 'clear water', and in some cases where it is not necessary to distinguish the terms, it will be referred to as 'clear water'. However, as described above, fresh water supplied to other consumers may also be cooling water supplied for cooling purposes.

In addition, in the present specification, the cooling water supplied to cool the engine combustion air and the fresh water supplied to the fresh water demand place may be fresh water obtained by desalination of seawater as described above, but are not limited thereto, and the combustion air cooler and fresh water to be described later It may be another fluid used as an intermediate medium such as glycol water that circulates through the consumer, but hereinafter, such a circulating fluid will be referred to as 'fresh water' or 'cooling water' as described above. However, the cooling water supplied to cool the engine combustion air and the fresh water supplied to the fresh water demand place are the same fluid circulating in the marine engine combustion air cooling system according to one embodiment of the present invention, and the cooled and supplied temperature is the same. number may be different.

In addition, in the present specification, the first refrigerant may be seawater, and the second refrigerant will be described as a preferred embodiment in which BOG is, but is not limited thereto, and the second refrigerant has a temperature lower than seawater while engine combustion in the ship Instead of the refrigerant provided separately to cool the air, another refrigerant demand source of the ship, for example, a cooling heat source such as liquid nitrogen for liquefying natural gas in a natural gas liquefaction system may be utilized.

In addition, in the present specification, a ship may be an FPSO, LNG carrier, passenger ship, cargo ship, oil tanker, etc. having self-navigation capability, or may be an offshore structure such as an offshore drilling structure floating or anchored in the sea for a certain period of time, and an engine (internal combustion engine) It is provided and can be applied to any ship that needs to cool the combustion air of the engine. However, it is equipped with a liquefied gas storage tank that stores cryogenic liquefied gas such as LNG (Liquefied Natural Gas) and LEG (Liquefied Ethane Gas) as engine fuel or cargo, and BOG (Boil) generated by natural vaporization from the liquefied gas storage tank. Off Gas) or limited to ships that can obtain refrigerants used in ship processes. Hereinafter, in order to explain one embodiment of the present invention, liquefied gas is LNG, that is, BOG will be described as an example of BOG generated in an LNG storage tank.

In addition, in this specification, an engine means an internal combustion engine capable of obtaining power by burning fuel, and may be a 2-stroke or 4-stroke engine, and may use oil as fuel, such as a diesel engine. -It may be a dual fuel engine that can be supplied as gas fuel by vaporizing liquefied gas such as LNG such as GI engine and DFDE, or a main propulsion engine or a power generation engine, but is not limited thereto. Any engine can be applied. However, it is preferable to be a dual fuel engine capable of receiving liquefied gas as fuel.

1 is a configuration diagram schematically illustrating a combustion air cooling system for a marine engine according to a first embodiment of the present invention, and FIG. 2 is a schematic diagram showing a cooling system for cooling combustion air for a marine engine according to a second embodiment of the present invention. FIG. 3 is a schematic diagram showing a combustion air cooling system for a marine engine according to a third embodiment of the present invention. Hereinafter, a marine engine combustion air cooling system and method according to an embodiment of the present invention will be described with reference to FIGS. 1, 2 and 3.

First, referring to FIGS. 1 to 3 , a marine engine combustion air cooling system and method commonly applicable to the first to third embodiments of the present invention will be described.

A marine engine combustion air cooling system according to an embodiment of the present invention, as shown in FIGS. 1 to 3, includes a combustion air cooler 400 for cooling combustion air of an engine (not shown), and the combustion air cooler In 400, combustion air cooled by the cooling water may be supplied to the engine by exchanging heat between the combustion air to be supplied to the engine and the cooling water.

In addition, the first cooler 200 cools the cooling water supplied to the combustion air cooler 400 by using the first refrigerant, and the first cooler 200 by sucking the first refrigerant, that is, seawater. ) and further includes a seawater pump 100 and a seawater supply line SL.

A plurality of seawater pumps 100 may be provided, and the number of seawater pumps 100 operated according to the required seawater supply amount or at least one operating speed (rpm) and load are adjusted to supply seawater as much as the required flow rate to the first cooler. (200) can be supplied. For example, in the embodiment of the present invention, three seawater pumps 100 may be provided, including the first seawater pump 100a, the second seawater pump 100b, and the third seawater pump 100c. 3 The seawater pump 100c may be provided with redundancy.

According to one embodiment of the present invention, VFD motors may be installed in each of the first to third seawater pumps 100 to enable VFD (Variable Frequency Drive) control. In addition, in the second cooling mode in which cooling water is cooled using a second refrigerant, which will be described later, compared to the first cooling mode in which cooling water is cooled using a first refrigerant, at least one seawater pump 100b is not operated, It can be operated by lowering the load of at least one or more seawater pumps 100a.

For example, when performing the second cooling mode to be described later, the heat load of the first cooler 200 is lowered according to the temperature required by the fresh water consumer, and the VFD motor is controlled accordingly to operate the seawater pump 100 and the fresh water pump. Energy can be saved by lowering the operating load of the 300 and pumping only the required amount of seawater.

In addition, according to one embodiment of the present invention, at least two first coolers 200 may be provided, and two or only one may be operated simultaneously according to the flow rate of fresh water to be cooled. For example, in the first cooling mode to be described later, both of the two first coolers 200a and 200b may be operated, and in the second cooling mode, only one first cooler 200b may be operated.

The fresh water cooled by the first refrigerant in the first cooler 200 is supplied to the combustion air cooler 400 or fresh water demand through the fresh water supply line FL, and the cooling water cooled in the first cooler 200 will be described later. It is sucked by the fresh water pump 300 according to the first to third embodiments, and the fresh water sucked by the fresh water pump 300 is supplied to the combustion air cooler 400 through the first circulation line FLb, or 3 It is supplied to the fresh water demand place through the circulation line (FLa).

The temperature of fresh water cooled by the first refrigerant in the first cooler 200 and supplied through the fresh water supply line FL may be about 36°C. This is characterized in that the temperature of the cooling water cooled by the second refrigerant in the second cooler 700 to be described later is higher.

According to one embodiment of the present invention, a plurality of fresh water pumps 300 may also be provided, and each fresh water pump 300 is provided with a VFD motor to save energy by VFD controlling its operating speed and load according to the cooling mode. It may be, and the number of fresh water pumps 300 operated according to the first and second cooling modes to be described later may vary.

In one embodiment of the present invention, the fresh water demander is an air condenser, an air compressor, a fuel oil cooler, a lubrication oil cooler, a generator-engine cooler ), etc., may be various equipment that uses fresh water in a ship.

In addition, the cooling water recovered after use in the combustion air cooler 400 and the cooling water recovered after use in the fresh water demand place are cooled and circulated again in the first cooler 200 through the recovery line FLc, or from the recovery line FLc. The temperature of the fresh water circulating through the fresh water supply line FL may be adjusted by including the branch line FLd that is branched and bypasses the first cooler 200 . However, the cooling water recovered after use in the combustion air cooler 400 is not supplied to the first cooler 200 through the recovery line FLc in the second cooling mode to be described later, but through the second circulation line FR to be described later. It can be supplied to the second cooler 700 through the

That is, according to one embodiment of the present invention, the cooling water discharged after cooling the combustion air in the combustion air cooler 400 is the temperature of the combustion air to be cooled in the combustion air cooler 400, the first cooler 200 The first circulation line FLb circulates to the first cooler 200 according to the temperature of the cooled water supplied to the combustion air cooler 400 and the second circulation line FLc circulates to the return line FLc or the second cooler 700. The flow path may be determined by the circulation line FR.

In addition, according to one embodiment of the present invention, a second circulation line (FR) for cooling the cooling water discharged after cooling the combustion air in the combustion air cooler 400 in the second cooler 700 by using the second refrigerant. It may include, and the second refrigerant may be BOG (Boil Off Gas) naturally occurring in the LNG storage tank (not shown) of the ship or a refrigerant utilized in other cooling or condensation or liquefaction processes of the ship. Therefore, a BOG or refrigerant supply line RL for supplying BOG or refrigerant to the second cooler 700 and recovering BOG or refrigerant discharged after heat exchange in the second cooler 700 is connected to the second cooler 700. do. However, the second refrigerant to be supplied to the second cooler 700 is not separately provided.

That is, in the second cooler 700, the combustion air cooling water and BOG or the combustion air cooling water and the refrigerant exchange heat, and the cooling water cooled in the second cooler 700 is supplied to the combustion air cooler 400 and circulated. The cooling water cooled in 700 and supplied to the combustion air cooler 400 is lower than the temperature of the cooling water cooled in the first cooler 200 and supplied to the combustion air cooler 400 .

The temperature of the BOG supplied to the second cooler 700 may be from about -40 ° C to -146 ° C, and the temperature of the second refrigerant, that is, BOG or the refrigerant supplied to the second cooler 700, may be about -40 ° C to -146 ° C. ) It is characterized in that it is lower than the temperature of the first refrigerant supplied to.

For example, LNG is liquefied at about -162°C under normal pressure and stored as engine fuel or cargo in an insulated storage tank in a liquid state at a temperature near that temperature. Even if the storage tank is insulated, this cryogenic liquefied gas continues to Natural vaporization generates BOG. BOG generated in the storage tank causes an increase in the internal pressure of the storage tank, so various means and devices to treat it are provided in the ship. According to the present invention, the second cooler 700 is a BOG supply line from the LNG storage tank ( RL) is connected, it can receive BOG and use it as a cooling heat source to cool the cooling water.

That is, according to the present invention, the temperature of the first refrigerant, that is, seawater, in the first heat exchanger 200 of the first circulation line FLb is too high, so that the temperature of the cooling water cooled by the seawater is reduced to the combustion air cooler 400. When the temperature of the combustion air cooled in is not sufficiently lowered, the cooling water supplied to the combustion air cooler 400 is slightly higher than the LNG stored in the storage tank. BOG discharged from the LNG storage tank is used. Therefore, regardless of the temperature of the seawater, the combustion air cooler 400 can cool the combustion air to the design minimum temperature.

In addition, according to an embodiment of the present invention, the ship's refrigerant demand is equipment using a refrigerant, such as a ship's air conditioning unit, an inert gas cooling unit, and a natural gas liquefaction unit. That is, in this specification, the second refrigerant may be a refrigerant that circulates through equipment using this refrigerant.

In addition, according to one embodiment of the present invention, whether the cooling water discharged after cooling the combustion air in the combustion air cooler 400 is circulated through the first circulation line FLb and the recovery line FLc, or the second circulation line ( FR), the first switching valve 500 for switching the flow path is provided at the rear end of the combustion air cooler 400, and the cooling water supplied to cool the combustion air to the combustion air cooler 400 is transferred to the first A second switching valve 800 for switching a flow path between supplying cooling water cooled by the cooler 200 and cooling water cooled by the second cooler 700 is provided in front of the combustion air cooler 400.

The first switching valve 500 and the second switching valve 800 may be provided as three-way valves, and the first switching valve 500 is a first circulation line leading from the rear end of the combustion air cooler 400. It may be provided at a point where the (FLb), the return line (FLc), and the second circulation line (FR) leading to the front end of the second cooler 700 meet, and thus, the first circulation line (FLb) and the second circulation line (FR) and the recovery line (FLc), and the second conversion valve 800 is connected to the second recovery line FR extending from the rear end of the second cooler 700 and the front end of the combustion air cooler 400. It may be provided at a point where the following first circulation line (FLb) or fresh water supply line (FL) meet, and thus the second circulation line (FR) and the first circulation line (FLb) or the second circulation line (FR) and fresh water It may be connected to the supply line FL. Conversion of the opening direction of the first switching valve 500 and the second switching valve 800 may be controlled by a control unit (not shown).

In this embodiment, the recovery line FLc is a section extending from the rear end of the combustion air cooler 400 and the rear end of the first switching valve 500 to the front end of the first cooler 200, and is referred to as one circulation line FLb. , denotes a section of the first circulation line FLb, but will be referred to as a recovery line FLc for convenience in describing the embodiments of the present invention.

Hereinafter, as shown in FIGS. 1 to 3, the cooling water and fresh water discharged after use from the combustion air cooler 400 of the first circulation line FLb and the fresh water demand place of the third circulation line FLa are recovered as one. Line FLc may be integrated and connected, and the first circulation line FLb and the third circulation line FLa may be respectively connected to the first cooler 200, but they may be integrated and connected as one recovery line FLc. Let's take that as an example. That is, the recovery line FLc includes a section of the first circulation line FLb and a portion of the third circulation line FLc, a section connected to the first cooler 200 from the combustion air cooler 400 and the rear end of the fresh water demand point. it means.

Hereinafter, first to third embodiments of a marine engine combustion air cooling system and method according to the first to third embodiments of the present invention will be described with reference to FIGS. 1 to 3 . Marine engine combustion air cooling systems and methods according to the first to third embodiments of the present invention cool the cooling water to cool the combustion air in the combustion air cooler 400 in the first cooler 200 using a first refrigerant. A first cooling mode and a second cooling mode for cooling in the second cooler 700 using a second refrigerant are included. In addition, as described above, according to an embodiment of the present invention, a plurality of seawater pumps 100, first coolers 200, and fresh water pumps 300 may be provided, but the number is separately limited. There is no, and the number of units provided and the number of units operated may be changed according to the required flow rate of fresh water or cooling water. However, in the first to third embodiments to be described below, three seawater pumps 100, two first coolers 200, and three fresh water pumps 300 or two combustion air cooling pumps 300A and The provision of two pumps 300B for consumers will be described as an example, and the change in the number of operating units according to the cooling mode to be described later may also change depending on circumstances, but the seawater pump 100 operated in the second cooling mode And the number of operating units of the first cooler 200 is smaller than the number of units operating in the first cooling mode. In addition, at least one seawater pump (100c) of the three seawater pumps (100), at least one fresh water pump (300c) of the three fresh water pumps (300) and at least one of the two combustion air cooling pumps (300A) At least one of the pump and the two pumps 300B may be provided as a redundancy pump capable of operating in an emergency situation, such as when the other one or more pumps are inoperable. As described above, the configuration according to the above-described embodiment can be equally applied to the first to third embodiments.

First, a marine engine combustion air cooling system and method according to a first embodiment of the present invention will be described with reference to FIG. 1 . As shown in FIG. 1, according to the first embodiment of the present invention, the fresh water cooled by the first refrigerant in the first cooler 200 is fresh water by the flow rate required by the combustion air cooler 400 and the fresh water consumer. After being pumped by the pump 300, the fresh water pumped by the fresh water pump 300, at the rear end of the fresh water pump 300, to the first circulation line FLb by the flow rate required by the combustion air cooler 400, It is branched and supplied to the third circulation line FLa as much as the flow rate required by the fresh water demand place. In addition, the second switching valve 800, as shown in Figure 1, the first circulation line (FLb) and the second cooler (700) connected from the rear end of the fresh water pump 300 to the front end of the combustion air cooler 400 ) It is provided at the branch point of the second circulation line (FR) connected from the rear end to the front end of the combustion air cooler 400, and is connected to the first circulation line (FLb) and the second circulation line (FR). That is, according to the first embodiment of the present invention, the configuration of the existing central fresh water cooling system is applied as it is, but the design change is minimized by adding a second circulation line (FR).

According to the first embodiment of the present invention, the circulation pump 600 circulates the cooling water discharged after cooling the combustion air in the combustion air cooler 400 to the second cooler 700 in the second circulation line FR. At least one or more may be provided.

<First cooling mode>

When operating in the first cooling mode, two seawater pumps 100a and 100b, two first coolers 200a and 200b, and two fresh water pumps 300a and 300b are operated, and the second cooler 700 and circulation Pump 600 is not running. In addition, the first switching valve 500 is opened to the combustion air cooler 400 and the recovery line FLc, and the second switching valve 800 is opened to the fresh water pump 300 and the combustion air cooler 400, In the first cooling mode, cooling water circulates through the first cooler 200, the fresh water pump 300, and the combustion air cooler 400.

When operating in the first cooling mode, fresh water obtained by heat exchange between fresh water and the first refrigerant in the first cooler 200 to cool the combustion air to a desired temperature is supplied to the combustion air cooler 400 . The first refrigerant, that is, seawater sucked by the seawater pump 100 is supplied to the first cooler 200 through the seawater supply line SL, cooled in the first cooler 200, and then discharged.

The cooling water cooled by the first refrigerant in the first cooler 200 is operated by at least two fresh water pumps 200a and 200b, and the fresh water pump 300 by the flow rate required by the combustion air cooler 400 and the fresh water consumer. is pumped by, and a flow rate required by the combustion air cooler 400 is introduced into the combustion air cooler 400 while flowing through the first circulation line FLb, or the remaining flow rate is branched into the third circulation line FLa to at least Some flows into the third circulation line FLa branched off from the first circulation line FLb, and requires fresh water cooled by the first refrigerant in the first cooler 200 to be supplied to the fresh water consumer (Other Machinery Group). . At this time, the temperature of the combustion air cooling water supplied to the first circulation line FLb among the cooled fresh water sucked by the fresh water pump 300 in the first cooling mode and the fresh water supplied to the third circulation line FLa are the same. do.

At this time, the second switching valve 800 is opened toward the first circulation line FLb and the combustion air cooler 400 so that the fresh water sucked by the fresh water pump 300 flows to the combustion air cooler 400.

The cooling water supplied to the combustion air cooler 400 is discharged after cooling the combustion air in the combustion air cooler 400, and is cooled by exchanging heat with seawater in the first cooler 200 along the return line FLc.

At this time, the first switching valve 500 is configured to supply the cooling water discharged from the combustion air cooler 400 to the first cooler 200 along the return line FLc of the first circulation line FLb, so that the combustion air cooler ( 400) and the recovery line FLc of the first circulation line FLb.

After cooling the combustion air supplied to the first cooler 200, all of the fresh water recovered from the cooling water and fresh water demand is supplied to the first cooler 200 through the recovery line FLc, and the entire amount is cooled by the first refrigerant. It can be sucked into the fresh water pump 300, or at least a portion of the flow rate bypasses the first cooler 200 through the branch line FLd branching at least a portion and is sucked into the fresh water pump 300, thereby cooling the cooling water. You can adjust the temperature.

As described above, the fresh water flowing through the first circulation line FLb and the third circulation line FLa may form a circulation cycle in which the first cooler 200 is cooled by the first refrigerant.

<Second Cooling Mode>

Alternatively, as shown in FIG. 1, the cooling water discharged after cooling the combustion air in the combustion air cooler 400 may be introduced into the second circulation line FR, by heat exchange with the first refrigerant, that is, seawater. When is not enough to cool the engine combustion air, the operator can cool the combustion air by cooling the coolant in the second cooler 700 of the second circulation line FR. The cooling water flowing through the second circulation line FR forms a circulation cycle in which it is cooled by the second refrigerant in the second cooler 700, cooled in the second cooler 700, and then supplied to the combustion air cooler 400 again. can do.

When operating in the second cooling mode, one seawater pump (100a), one first cooler (200a), one fresh water pump (300a) and a second cooler (700), and a circulation pump (600) are operated. In addition, the first switching valve 500 opens toward the combustion air cooler 400 and the second circulation line FR, and the second switching valve 800 opens toward the second cooler 700 and the combustion air cooler 400. Opened, in the second cooling mode, the cooling water circulates through the combustion air cooler 400, the circulation pump 600, and the second cooler 700, and even when the temperature of the first refrigerant is not sufficiently low, the combustion air at a lower temperature can be supplied to the engine.

The control unit (not shown) determines that the temperature of the cooling water supplied to the combustion air cooler 400 is not sufficient only by cooling with the first refrigerant, and the cooling water discharged from the combustion air cooler 400 flows through the second circulation line FR. To open the first switching valve 500 to the second circulation line (FR) side so as to flow to. At this time, the first switching valve 500 may be opened 100% toward the second circulation line FR so that all of the cooling water discharged from the combustion air cooler 600 flows into the second circulation line FR, or gradually A part of the cooling water discharged from the combustion air cooler 600 by opening toward the second circulation line FR may flow through the first circulation line FLb and the remaining part may go through a transitional period in which it flows into the second circulation line FR. have.

The circulation pump 600 provided in the second circulation line FR is discharged from the combustion air cooler 400 so that the cooling water flows from the combustion air cooler 400 to the second cooler 700, and then the first switching valve FR ), the cooling water introduced into the second circulation line (FR) is pumped.

The cooling water supplied to the circulation pump 600 by the second cooler 700 exchanges heat with the second refrigerant supplied to the refrigerant supply line RL, and is cooled in the first cooler 200 to a lower temperature than the cooling water discharged. cooled and discharged.

The entire amount of the cooling water pumped by the circulation pump 600 may be supplied to the second cooler 700. By controlling the valve V1, the temperature supplied to the combustion air cooler 400 can be adjusted.

However, the temperature of the cooling water supplied to the combustion air cooler 400 through the second circulation line FR is lower than the temperature of the cooling water cooled by the first refrigerant in the first cooler 200.

That is, until the temperature of seawater, that is, the first refrigerant is sufficiently low to cool the combustion air, the operator performs the second cooling mode to cool the combustion air while the cooling water circulates through the second circulation line FR. can

When the coolant flows through the second circulation line FR, the control unit changes the opening direction of the second switching valve 800 provided at the front end of the combustion air cooler 400 to the first circulation line FLb side to the second circulation line FLb. The opening direction is switched so as to open toward the circulation line FLb. Like the first switching valve 500, it may be 100% open toward the second circulation line FLb, or it may go through a transitional period in which the opening is gradually switched.

That is, according to the first embodiment of the present invention, when cooling is performed in the second cooler 700 by allowing the cooling water to flow through the second circulation line FR, the control unit operates the circulation pump 600 and the second cooler 700 is operated, and the refrigerant supply line (RL) can be opened so that BOG is supplied to the refrigerant supply line (RL), and the first switching valve 500 and the second switching valve 700 are connected to the second circulation line (FR) can be controlled to open to the side.

In addition, when the combustion air cooling water is cooled by the second cooler 700 in the second circulation line FR, the control unit stops the operation of at least one of the fresh water pumps 300a, 300b, and 300c or lowers the operation speed to cool the cooling water. It is possible to pump fresh water with a smaller flow rate than when cooling the first cooler 200 in the first circulation line FLb.

That is, in the second cooling mode, since the cooling water circulating in the combustion air cooler 400 circulates in the second circulation line FR by the circulation pump 600, the fresh water pump 300 controls only fresh water to be supplied to the fresh water demand place. At least one fresh water pump (300a) of the plurality of fresh water pumps (300) operating to supply cooling water to the combustion air cooler (400) in one cooling mode may not operate. In addition, since the first cooler 200 does not have to cool the amount of fresh water to be supplied to the fresh water supply line FL, that is, the amount of cooling water to be supplied to the combustion air cooler 400, at least one first cooler 200a It may not work, and the seawater pump 100 is also the same.

The number of seawater pumps 100a, 100b, 100c, first coolers 200a, 200b, and fresh water pumps 300a, 300b, 300c operating in the second cooling mode is at least one greater than the number of units operating in the first cooling mode. characterized by less.

When the second cooling mode is implemented, since the fresh water pump 300 does not have to suck in the cooling water to be supplied to the combustion air cooler 400, the sea water pump 100, the first cooler 200 and the fresh water pump 300 do not 3 circulation line (FLa), that is, only the number of units corresponding to the flow rate of fresh water to be supplied to the fresh water consumer needs to be operated.

In general, since the circulation pump 600 is provided with a smaller capacity than the fresh water pump 300a and consumes less power, it is possible to significantly reduce operating costs and energy. On the other hand, since the fresh water to be supplied to the fresh water consumer does not have to have a temperature as low as the cooling water for cooling the combustion air of the engine, the central fresh water cooling system manages and controls the temperature of the cooling water for the combustion air cooler 400 and the fresh water for the fresh water consumer dually. can do.

Next, a marine engine combustion air cooling system and method according to a second embodiment of the present invention will be described with reference to FIG. 2 . The second embodiment is a modified example of the first embodiment, and hereinafter, only configurations modified from the first embodiment will be described.

According to the second embodiment of the present invention, as shown in FIG. 2, the second circulation line (FR) is connected to the first circulation line (FLb) by the first switching valve 501 at the rear end of the combustion air cooler 401. It is branched from, and is connected from the rear end of the second cooler 700 to the front end of the fresh water pump 300 by the second switching valve 800.

A boosting pump 601 for pressurizing the cooling water discharged from the combustion air cooler 400 to be supplied to the second cooler 700 is provided in the second circulation line FR.

Hereinafter, with reference to FIG. 2, the operation of the marine engine combustion air cooling system according to the second embodiment of the present invention will be described. However, since the same applies to the first cooling mode as in the first embodiment, the description thereof will be omitted and only the case of the second cooling mode will be described.

<Second Cooling Mode>

According to the second embodiment of the present invention, when operating in the second cooling mode, one seawater pump 100a, one first cooler 200a, two fresh water pumps 300a and a second cooler 700, The boosting pump 601 is operated. In addition, the first switching valve 500 is opened toward the combustion air cooler 400 and the second circulation line FR, and the second switching valve 800 opens toward the second cooler 700 and the fresh water pump 300. In the second cooling mode, the cooling water circulates through the combustion air cooler 400, the boosting pump 601, the second cooler 700, and the fresh water pump 300a, even when the temperature of the first refrigerant is not sufficiently low, Low-temperature combustion air can be supplied to the engine.

When cooling the combustion air cooling water in the first cooler 200 using the first refrigerant, that is, seawater, is not sufficient, the operator cools the combustion air in the second cooler 700 of the second circulation line FR. A second cooling mode in which combustion air is cooled by cooling may be performed.

The control unit operates the boosting pump 601 and the second cooler 700 in the second cooling mode and changes the opening directions of the first selector valve 500 and the second selector valve 800.

In order to cool the cooling water that has passed through the combustion air cooler 400 in the second cooler 700, the control unit opens the first switching valve 500 toward the combustion air cooler 400 and the second circulation line FR.

In addition, the control unit operates the boosting pump 601 so that the boosting pump 601 sucks the cooling water that has passed through the combustion air cooler 400 and pumps it to the second cooler 701, and the refrigerant supply line RL By opening, BOG is supplied to the second cooler 700.

At this time, the cooling water sucked by the boosting pump 601 may be cooling water whose temperature has risen after being cooled with combustion air in the combustion air cooler 400, and a line (not shown) bypassing the combustion air cooler 400. It may be further provided and directly supplied to the second cooler 700 without passing through the combustion air cooler 400.

The cooling water supplied to the second cooler 700 by the boosting pump 601 is cooled by heat exchange with the second refrigerant in the second cooler 700, and the cooling water cooled by heat exchange with the second refrigerant in the second cooler 700. After being discharged from the second cooler 700, it is pumped by the fresh water pump 300a and supplied to the combustion air cooler 400.

At this time, the controller opens the second switching valve 801 to the front side of the second circulation line FR and the fresh water pump 300, and the cooling water cooled in the second cooler 700 is pumped by the fresh water pump 300. and supplied to the combustion air cooler 400.

The temperature of the cooling water supplied to the combustion air cooler 400 through the second circulation line FR is lower than the temperature of the cooling water cooled by the first refrigerant in the first cooler 200. That is, until the temperature of seawater, that is, the first refrigerant is sufficiently low to cool the combustion air, the operator performs the second cooling mode to cool the combustion air while the cooling water circulates through the second circulation line FR. can

The number of operating seawater pumps (100a, 100b, 100c) and first coolers (200a, 200b) operating in the second cooling mode according to the second embodiment is at least one less than the number operating in the first cooling mode. to be

The seawater pumps 100a, 100b, and 100c and the fresh water pumps 300a, 300b, and 300c are equipped with VFD (Variable Frequency Drive) motors, and when the second cooling mode is performed, the first Energy can be saved by lowering the thermal load of the cooler 200 and controlling the VFD motor accordingly to lower the operating load of the seawater pump 100 and the fresh water pump 300 so that only the necessary amount of seawater is pumped.

In addition, according to the second embodiment, the head of any one of the fresh water pumps 300a among the fresh water pumps 300a, 300b, and 300c being operated by the boosting pump 601 in the second cooling mode is reduced. It can be done, and thus the load of the fresh water pump (300a) can be reduced.

Next, a marine engine combustion air cooling system and method according to a third embodiment of the present invention will be described with reference to FIG. 3 . The third embodiment is a modified example of the first embodiment, and hereinafter, only configurations modified from the first embodiment will be described.

As shown in FIG. 3, the marine engine combustion air cooling system according to the third embodiment of the present invention sucks the cooling water cooled in the first cooler 200 or the second cooler 700 to cool the combustion air (400). ) It is characterized in that a combustion air cooling pump (300A) for supplying, and a pump (300B) for supplying fresh water cooled in the first cooler 200 to a fresh water consumer are provided, respectively.

That is, according to the third embodiment of the present invention, the temperature of the cooling water for cooling the combustion air and the fresh water to be supplied to the fresh water consumer can be independently controlled and operated in two ways.

<First cooling mode>

For example, in the first cooling mode according to the third embodiment of the present invention, at least two seawater pumps 100a and 100b are operated to suck seawater, and through the seawater supply line SL, the first cooler 200 ), and at least two first coolers 200a and 200b are operated to exchange heat between seawater and fresh water, and fresh water cooled by seawater in the first coolers 200a and 200b is supplied through a fresh water supply line FL. transported through

The cooled fresh water transferred to the fresh water supply line FL is supplied to the first circulation line FLb and the third circulation line FLa according to the required flow rate. At this time, at least one of the first circulation lines FLb The combustion air cooling pump (300A) of the table is operated to suck coolant, and the sucked coolant is pumped to the combustion air cooler (400). The cooling water supplied to the combustion air cooler 400 cools the engine combustion air by exchanging heat with the engine combustion air. Cooling water discharged from the combustion air cooler 400 after cooling the engine combustion air is returned to the first cooler 200 along the recovery line FLc, cooled by seawater in the first cooler 200, and circulated.

At this time, the second switching valve 800 is the fresh water pump 200 and the combustion air cooler 400 so that the cooling water pumped through the first circulation line FLb by the fresh water pump 200 is supplied to the combustion air cooler 400. ) side, and the first switching valve 800 cools the combustion air in the combustion air cooler 400 and supplies the discharged cooling water to the first cooler 200 along the recovery line FLc. It is controlled to open toward the air cooler 400 and the return line FLc.

In addition, in the third circulation line FLa, the fresh water cooled in the first cooler 200 is sucked by operating at least one pump 300B for the customer, and the sucked fresh water is pumped and supplied to the customer. The fresh water discharged after use at the fresh water demand place is returned to the first cooler 200 along the recovery line FLc, cooled by seawater in the first cooler 200, and circulated. At least a portion of the fresh water recovered through the recovery line FLc bypasses the first cooler 200 along the branch line FLd so that the temperature of the fresh water supplied to the fresh water consumer can be adjusted. On the other hand, the temperature of the cooling water supplied to the combustion air cooler 400 can be adjusted by a second cooling mode to be described later.

In the first cooling mode according to the third embodiment of the present invention, the second cooler 700 is not operated, and the number of first coolers 200 and seawater pumps 100 operated in the second cooling mode to be described later is greater than At least one of each is further activated.

<Second Cooling Mode>

For example, the second cooling mode according to the third embodiment of the present invention is characterized in that the cooling water discharged from the combustion air cooler 400 is cooled in the second cooler 700. At this time, the control unit 2 The cooler 700 is operated, and the BOG supply line RL for supplying the second refrigerant for cooling the cooling water to the second cooler 700, for example, BOG, is opened. In addition, the controller controls the combustion air cooler 400 and the second switching valve 500 so that the cooling water discharged from the combustion air cooler 400 is supplied to the second cooler 700 through the second circulation line FR. The circulation line FR is controlled to open toward the second cooler 700, and the cooling water cooled by the second refrigerant in the second cooler 400 and discharged can be supplied to the combustion air cooler 400. The switching valve 800 is controlled to open toward the second cooler 700 of the second circulation line FR and the combustion air cooling pump 300A. That is, the cooling water for cooling the combustion air in the combustion air cooler 400 forms a cycle in which the second circulation line FR including the second cooler 700 circulates.

In addition, as a fresh water demand point, fresh water cooled in the first cooler 200 is supplied, at least one seawater pump 100a is operated to suck seawater, and the first cooler 200 through the seawater line SL At least one second cooler 200a is operated to exchange heat between seawater and fresh water, and fresh water cooled by seawater in the first cooler 200a is transported through the fresh water supply line FL.

The cooled fresh water transferred to the fresh water supply line FL is supplied to the third circulation line FLa, and at least one pump 300B for a customer is operated to suck fresh water and pump and supply it to a fresh water customer. The fresh water discharged after use at the fresh water demand place is returned to the first cooler 200a along the recovery line FLc, cooled by seawater in the first cooler 200a, and circulated. At least a portion of the fresh water recovered through the recovery line FLc bypasses the first cooler 200a along the branch line FLd so that the temperature of the fresh water supplied to the fresh water consumer can be adjusted.

In the second cooling mode, the temperature of the cooling water circulating in the second circulation line and supplied to the combustion air cooler 400 is lower than the temperature of the fresh water circulating in the third circulation line and supplied to the fresh water consumer, In the second cooling mode according to the third embodiment, compared to the above-described first cooling mode, at least one seawater pump 100 and at least one first cooler 200 are operated less.

That is, according to the third embodiment of the present invention, in a ship using a central fresh water system, the temperature of the cooling water supplied to the combustion air cooler 400 requiring cooling to a relatively lower temperature, and a relatively higher temperature It is possible to manage the temperature of fresh water supplied to the fresh water demand place that needs fresh water at the temperature in two ways, and it is possible to use an appropriate combination of the number of devices operated by mode or load, etc., so energy can be saved.

Therefore, according to an embodiment of the present invention, engine combustion air can be cooled to a minimum temperature using BOG, and engine combustion air can be sufficiently cooled even when the temperature of seawater is high, thereby improving engine efficiency. In addition, it is possible to save energy by optimizing the operation combination and capacity of a pump, cooler, etc. for each mode by minimizing design changes such as adding a second circulation line (FR) in the existing fresh water cooling system. In addition, energy consumed in the system can be saved by using BOG as a cooling heat source.

As described above, the embodiments according to the present invention have been reviewed, and the fact that the present invention can be embodied in other specific forms in addition to the above-described embodiments without departing from the spirit or scope is apparent to those skilled in the art. It is self-evident to Therefore, the foregoing embodiments should be regarded as illustrative rather than restrictive, and thus the present invention is not limited to the foregoing description, but may be modified within the scope of the appended claims and their equivalents.

100: seawater pump
200: first cooler
300: fresh water pump
400: combustion air cooler
600: first switching valve
700: second cooler
800: second switching valve
FLb: 1st circulation line
FR: 2nd circulation line

Claims (13)

a combustion air cooler that cools the combustion air of the engine;
one or more first coolers provided to cool cooling water using a first refrigerant and supply it to other fresh water demand sources besides the combustion air cooler and the combustion air cooler;
one or more seawater pumps supplying seawater to the first cooler; and
A second cooler for cooling the cooling water discharged after cooling the combustion air in the combustion air cooler using a second refrigerant; including,
The second refrigerant is BOG supplied through a BOG supply line, and in the second cooler, the cooling water and BOG exchange heat,
The combustion air cooler,
a first cooling mode in which combustion air is cooled by receiving cooling water cooled by the first cooler; and
a second cooling mode in which combustion air is cooled by receiving cooling water cooled by the second cooler; Operates in one of the modes,
The number of seawater pumps and first coolers that operate when operating in the first cooling mode and the second cooling mode is different,
A marine engine combustion air cooling system in which the number of seawater pumps and first coolers operated in the second cooling mode is smaller than the number of seawater pumps and first coolers operated in the first cooling mode. The method of claim 1,
a first circulation line in which the first cooler is provided; and
It further includes; a second circulation line in which the second cooler is provided,
In the first circulation line,
A plurality of fresh water pumps supplying the cooling water cooled by the first refrigerant in the first cooler to the combustion air cooler and the fresh water demand place; provided, the marine engine combustion air cooling system. The method of claim 2,
In the second circulation line,
A circulation pump for circulating the cooling water discharged from the combustion air cooler to the second cooler is provided,
The second circulation line,
It is connected from the rear end of the combustion air cooler to the rear end of the plurality of fresh water pumps,
When the circulation pump is operated,
A marine engine combustion air cooling system capable of stopping the operation of at least one of the fresh water pumps. The method of claim 2,
In the second circulation line,
A boosting pump supplying the cooling water discharged from the combustion air cooler to the second cooler; is provided,
The second circulation line is connected from the rear end of the combustion air cooler to the front end of the plurality of fresh water pumps,
When the boosting pump is operated,
A marine engine combustion air cooling system capable of reducing the operating load of at least one of the fresh water pumps. According to claim 3 or 4,
a first switching valve provided at a rear end of the combustion air cooler and controlling a passage so that the cooling water flows into the first circulation line or the second circulation line; and
Further comprising a second switching valve provided in front of the combustion air cooler,
The first switching valve,
Switching a flow path so that the cooling water discharged from the combustion air cooler is supplied to the first cooler or the second cooler;
The second switching valve,
A marine engine combustion air cooling system for switching a flow path so that the cooling water cooled in the first cooler or the cooling water cooled in the second cooler is supplied to the combustion air cooler. The method of claim 5,
The second switching valve,
The marine engine combustion air cooling system for switching the flow path so that the fresh water pump sucks the cooling water cooled in the second cooler or the cooling water cooled in the first cooler. cooling the cooling water in a first cooler;
Pumping the cooled cooling water and supplying it to a fresh water demand place other than a combustion air cooler for cooling engine combustion air and a combustion air cooler; and
Selecting a first cooling mode that circulates the cooling water after cooling engine combustion air in the combustion air cooler to the first cooler or a second cooling mode that circulates it to a second cooler,
In the first cooling mode and the second cooling mode, the number of seawater pumps supplying the first refrigerant operated and the first cooler is different,
The marine engine combustion air cooling system operating method in which the number of seawater pumps and first coolers operated in the second cooling mode is smaller than the number of seawater pumps and first coolers operated in the first cooling mode. The method of claim 7,
In the first cooler, the cooling water after cooling the engine combustion air is cooled using seawater,
In the second cooler, the cooling water after cooling the engine combustion air using BOG is cooled. The method of claim 7,
supplying at least a portion of the pumped cooling water to a fresh water consumer; and
Recovering the fresh water after being supplied to the fresh water demand place and circulating it to the first cooler; including, Marine engine combustion air cooling system operating method. delete delete The method of claim 7,
The second cooling mode,
A method of operating a combustion air cooling system for a marine engine that lowers the operating load of at least one seawater pump and at least one fresh water pump than the first cooling mode. The method of claim 12,
controlling an opening direction of a first switching valve to cool the combustion air and then converting a flow path of cooling water discharged; and
Controlling the opening direction of the second switching valve to switch the flow path of the cooling water cooled by the first cooler or the second cooler and supplied to cool the combustion air; Including,
Switching to the first cooling mode or the second cooling mode, marine engine combustion air cooling system operating method.

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