Gas processing system and vessel containing same

Abstract

To provide a gas processing system saving use of energy by heating with liquefied gas flowing in waste heat of coolant heated by an engine into the engine and a vessel including the same.SOLUTION: A gas processing system and a vessel including the same includes: a fuel supply line for supplying fuel to a main engine; a heat exchanger provided in the fuel supply line for heating the fuel; and a coolant circulation line for the main engine provided to supply a heat source for the heat exchanger, wherein the coolant circulation line is provided to be separable into a first coolant circulation line for circulating in the heat exchanger and a second coolant circulation line for circulating in the main engine.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a gas processing system and a vessel including the same. [Background technology]

[0002] A ship is a means of transportation that sails across the ocean carrying large amounts of minerals, crude oil, natural gas, or thousands of containers.Made of steel, it floats above the waterline due to buoyancy and moves using the thrust generated by the rotation of a propeller.

[0003] Such vessels generate thrust by driving engines or gas turbines. The engine uses oil fuel such as gasoline or diesel to move pistons, which rotate the crankshaft through the reciprocating motion of the pistons. The shaft connected to the crankshaft rotates and drives the propeller. Gas turbines burn fuel together with compressed air, and use the temperature and pressure of the combusted air to rotate turbine blades to generate electricity, which is then transmitted to the propeller.

[0004] However, recently, LNG carriers that transport liquefied natural gas (LNG), a type of liquefied gas, have begun using an LNG fuel supply system in which LNG is used as fuel to drive engines, turbines, and other destinations.Since LNG is a clean fuel and its reserves are more abundant than oil, the system of using LNG as fuel at destinations is also being applied to ships other than LNG carriers.

[0005] However, compared to the conventional use of oil fuels such as diesel, there are still several issues that need to be resolved when using LNG, which is a gas fuel, and research and development is ongoing into technologies to use LNG, a clean fuel, and supply it to onboard customers. Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention has been created to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide a gas treatment system and a ship including the same that can save energy by utilizing waste heat from cooling water heated by an engine to heat liquefied gas flowing into the engine. [Means for solving the problem]

[0007] A gas processing system according to one aspect of the present invention includes a first fuel supply line that supplies fuel to a main engine, a second fuel supply line that branches off from the first fuel supply line and supplies fuel to an auxiliary engine, a heat exchanger that is provided in the first fuel supply line and heats the fuel, and a cooling water circulation line for the main engine that is provided to supply a heat source to the heat exchanger, wherein the cooling water circulation line is provided so as to be separable into a first cooling water circulation line that circulates through the heat exchanger and a second cooling water circulation line that circulates through the main engine.

[0008] Specifically, the engine coolant circulation system may further include a first branch line connecting both ends of the first coolant circulation line so that the coolant bypasses the main engine and circulates through the heat exchanger, and a second branch line connecting both ends of the second coolant circulation line so that the coolant bypasses the heat exchanger and circulates through the main engine.

[0009] Specifically, the backup heater is provided in the first cooling water circulation line or the first branch line, and the backup heater can heat the cooling water and supply it to the heat exchanger when the load of the main engine is less than a preset value or when the cooling water bypasses the main engine via the first branch line.

[0010] Specifically, when the coolant is supplied to the heat exchanger via the main engine through the coolant circulation line, the engine may further include a bypass line provided to bypass the backup heater.

[0011] Specifically, the first branch line may allow the cooling water to bypass the main engine and circulate through the heat exchanger when the main engine is stopped.

[0012] Specifically, the cooling water can circulate along the entire cooling water circulation line and pass through the heat exchanger and the main engine, or circulate along the first cooling water circulation line and the first branch line and bypass the main engine and pass through the heat exchanger, or circulate along the second cooling water circulation line and the second branch line and bypass the heat exchanger and pass through the main engine.

[0013] Specifically, a first closed loop formed by the first cooling water circulation line and the first branch line may be provided independently of a second closed loop formed by the second cooling water circulation line and the second branch line.

[0014] Specifically, the cooling system may further include an expansion tank for adjusting the pressure of the cooling water flowing along the first closed loop or the second closed loop.

[0015] A ship according to one aspect of the present invention includes the gas processing system described above. [Effects of the Invention]

[0016] The gas treatment system and the ship including the same according to the present invention can realize efficient vaporization of liquefied gas by heating the liquefied gas using the cooling water used in the main engine, and can ensure stable heating of the liquefied gas even when the main engine is stopped or the heat quantity of the cooling water is insufficient. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a schematic diagram of a gas processing system according to one embodiment of the present invention; [Figure 2] 1 is a schematic diagram of a gas processing system according to one embodiment of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0018] The objectives, particular advantages, and novel features of the present invention will become more apparent from the following detailed description and preferred embodiments taken in conjunction with the accompanying drawings. In this specification, when referring to components in each drawing, please note that the same components are numbered as much as possible even if they appear in different drawings. Furthermore, when describing the present invention, detailed descriptions of related publicly known technologies will be omitted if it is determined that such descriptions would unnecessarily obscure the gist of the present invention.

[0019] Hereinafter, the term "fuel" may be a liquefied gas, which may be LPG, LNG, ethane, or the like, and may refer to, for example, LNG (Liquefied Natural Gas), and the term "evaporated gas" may refer to BOG (Boil Off Gas), which is naturally evaporated LNG. Hereinafter, the term "liquefied gas" may be used as a term that encompasses a liquid state, a naturally evaporated gas state, or a forcedly evaporated gas state. However, the term "evaporated gas" may be used as a term that refers to gas that has naturally evaporated in a liquefied gas storage tank.

[0020] For reference, the present invention includes a ship equipped with the gas processing system described below. In this case, the term "ship" may be a general commercial ship or a comprehensive expression that includes offshore plants such as FLNG and FSRU, and may also be replaced with a plant installed on land.

[0021] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0022] 1 and 2 are conceptual diagrams of a gas processing system according to one embodiment of the present invention.

[0023] For reference, Figure 1 shows a state where the load on the main engine E1 is equal to or greater than the preset value, while Figure 2 shows a state where the load on the main engine E1 is less than the preset value or the main engine E1 is not operating.

[0024] 1 and 2, a gas processing system 1 according to one embodiment of the present invention includes a liquefied gas storage tank 10, a cooling water pump 21, a cooling water cooler 22, a fresh water generator 23, a heat exchanger 30, a booster pump 41, a backup heater 42, and a gas separator 43.

[0025] In this case, the cooling water pump 21, the cooling water cooler 22, the fresh water generator 23, the heat exchanger 30, the booster pump 41, the backup heater 42, and the gas separator 43 may be arranged along the cooling water circulation line L20, and as will be described later, the cooling water pump 21, the cooling water cooler 22, and the fresh water generator 23 may be arranged in a first closed loop, and the heat exchanger 30, the booster pump 41, the backup heater 42, and the gas separator 43 may be arranged in a second closed loop.

[0026] The liquefied gas storage tank 10 stores liquefied gas. The liquefied gas storage tank 10 is an independent tank according to IMO regulations, and may be a type A, B, C, etc., or may be a membrane tank.

[0027] The liquefied gas storage tank 10 can store liquefied gas at extremely low temperatures, but when heat from the outside penetrates, the liquefied gas naturally evaporates, generating evaporated gas. At this time, the evaporated gas causes an increase in the internal pressure of the liquefied gas storage tank 10, so the evaporated gas can be discharged to the outside in order to maintain a stable internal pressure of the liquefied gas storage tank 10.

[0028] The liquefied gas (and / or evaporated gas) stored in the liquefied gas storage tank 10 may be supplied to engines E1, E2, etc., which are the demand destinations, and used. In this case, the engines E1, E2 may include a main engine E1 (ME-GI, X-DF, ME-LGI, ME-GIE, etc.) for propelling the ship, and an auxiliary engine E2 as a power generation engine for covering the power load on the ship.

[0029] A fuel supply line L30 may be provided to supply the liquefied gas stored in the liquefied gas storage tank 10 to the engines E1 and E2. Specifically, the fuel supply line L30 may include a first fuel supply line L31 for supplying the liquefied gas to the main engine E1 and a second fuel supply line L32 for supplying the liquefied gas to the auxiliary engine E2. In this case, a heat exchanger 30 may be provided in the first fuel supply line L31, and the second fuel supply line L32 may branch off from the first fuel supply line L31 downstream of the heat exchanger 30 and be connected to the auxiliary engine E2. In addition, the first and second fuel supply lines L31 and L32 may be provided with a valve (reference numeral not shown) or a gas valve unit (reference numeral not shown) for controlling the flow rate of the liquefied gas.

[0030] The coolant circulation line L20 may include a first coolant circulation line L20a that circulates through the heat exchanger 30 and a second coolant circulation line L20b that circulates through the main engine E1, and the first coolant circulation line L20a and the second coolant circulation line L20b may be interconnected to form a closed loop. Also, the first and second coolant circulation lines L20a and L20b may be provided so that the coolant flows can be separated from each other.

[0031] In the following, the cooling water pump 21, the cooling water cooler 22, and the fresh water generator 23 provided on the cooling water circulation line L20 on the main engine E1 side (second cooling water circulation line L20b) will be first described.

[0032] The cooling water pump 21 pumps the cooling water so that the cooling water circulates along the cooling water circulation line L20. The cooling water circulation line L20, to which the cooling water pump 21 is provided, can form a closed loop to circulate the cooling water to the main engine E1, which uses liquefied gas as fuel, and to a heat exchanger 30, which will be described later. However, the cooling water described in this specification may also be used for the auxiliary engine E2 in addition to the main engine E1.

[0033] The cooling water pump 21 may be disposed upstream of the main engine E1 in the cooling water circulation line L20, or a plurality of pumps may be provided in parallel to back up each other.

[0034] The cooling water pump 21 can supply cooling water cooled by a cooling water cooler 22 (described later) to the main engine E1, and the cooling water pump 21 may be provided downstream of the cooling water cooler 22 as shown in the figure. Alternatively, the cooling water pump 21 may be provided upstream of the cooling water cooler 22 in the cooling water circulation line L20, unlike the figure.

[0035] The coolant cooler 22 cools the coolant that has been heated while passing through the main engine E1. The coolant cooler 22 can cool the coolant using various refrigerants such as seawater, fresh water, or air, and may be located upstream of the coolant pump 21 in the coolant circulation line L20.

[0036] The coolant circulation line L20 is provided so that at least a portion of the coolant can bypass the coolant cooler 22, thereby adjusting the temperature of the coolant downstream of the coolant cooler 22. That is, when the amount of coolant that bypasses the coolant cooler 22 among the coolant flowing upstream of the coolant cooler 22 increases, the temperature downstream of the coolant cooler 22 increases, and conversely, when the amount of coolant that bypasses the coolant cooler 22 decreases, the temperature downstream of the coolant cooler 22 decreases.

[0037] The amount of coolant bypassing the coolant cooler 22 may be determined according to the temperature of the coolant delivered to the coolant cooler 22, or according to the load of the main engine E1, which affects the temperature of the coolant.

[0038] The fresh water generator 23 generates fresh water by utilizing waste heat from the cooling water. The fresh water generator 23 may be one that uses high-temperature cooling water discharged from the main engine E1 to heat seawater or the like to generate steam, and then generates fresh water from the steam. Alternatively, the fresh water generator 23 may use a so-called system that can heat fresh water using cooling water.

[0039] The fresh water generator 23 can deliver fresh water to a fresh water tank (not shown), and the cooling water can bypass the fresh water generator 23 if the fresh water tank has sufficient storage capacity or if additional fresh water production is not required.

[0040] That is, as described in the cooling water cooler 22, the cooling water circulation line L20 may be provided to bypass the fresh water generator 23. In addition, since the temperature of the cooling water can be lowered as it passes through the fresh water generator 23, the temperature of the cooling water downstream of the fresh water generator 23 can be adjusted by adjusting the amount of cooling water that bypasses the fresh water generator 23 in the cooling water circulation line L20.

[0041] The fresh water generator 23 is installed upstream of the coolant cooler 22 in the coolant circulation line L20 so that the high-temperature coolant discharged from the main engine E1 can be primarily cooled through the fresh water generator 23 and then secondarily cooled in the coolant cooler 22.

[0042] The cooling water circulation line L20 is provided with first and second branch lines L21 and L22, so that the cooling water can circulate in a closed loop formed by the cooling water circulation line L20, or in first and second closed loops formed by the first and second branch lines L21 and L22, as will be described in detail below.

[0043] The heat exchanger 30 heats the liquefied gas and supplies it to the main engine E1 or the auxiliary engine E2, etc. The heat exchanger 30 is configured to exchange heat between a heat medium and the liquefied gas, and may be of a shell-and-tube, bath type, PCHE, or other type, but is not limited to these types.

[0044] The heat exchanger 30 is provided on the first fuel supply line L31 and may include a flow path for the liquefied gas and a flow path for the heat transfer medium. The liquefied gas is heated in the heat exchanger 30 to a temperature required by the engines E1, E2 before being transferred to the engines E1, E2. The heat transfer medium flows into the heat exchanger 30 at a high temperature and is cooled by the liquefied gas before exiting the heat exchanger 30.

[0045] In this embodiment, the heat medium may be the coolant used in the engines E1 and E2. The heat exchanger 30 may be of a type that directly exchanges heat between the liquefied gas and the coolant, and the coolant may be the coolant used in the main engine E1 of the engines E1 and E2. Therefore, one side of the heat exchanger 30 may be connected to the first fuel supply line L31, and the other side may be connected to the coolant circulation line L20 through which the coolant flows.

[0046] Of course, the present invention may also include an indirect heat exchange system in which the heat medium of the heat exchanger 30 is heated by the cooling water, rather than a direct heat exchange system in which the cooling water flows directly through the heat exchanger 30.

[0047] One heat exchanger 30 may be provided as shown in the figure, or two or more may be provided. When a plurality of heat exchangers 30 are provided, the plurality of heat exchangers 30 may be provided in series and / or parallel, and separate heat exchangers 30 may be assigned to the main engine E1 and the auxiliary engine E2, respectively.

[0048] The booster pump 41, the backup heater 42, and the gas separator 43 provided on the coolant circulation line L20 on the heat exchanger 30 side (first coolant circulation line L20a) will be described below.

[0049] The booster pump 41 pumps high-temperature coolant discharged from the main engine E1 to the heat exchanger 30. The booster pump 41 may be disposed upstream of the heat exchanger 30 in the coolant circulation line L20, and may have a function similar to that of the coolant pump 21 described above.

[0050] The booster pump 41 may pressurize the cooling water in accordance with the pressure of the liquefied gas flowing into the heat exchanger 30 in order to minimize the pressure difference between the liquefied gas and the cooling water in the heat exchanger 30. In this case, the discharge pressure of the booster pump 41 may be relatively higher than the discharge pressure of the cooling water pump 21.

[0051] Like the cooling water pump 21, multiple booster pumps 41 may be installed in parallel or in series. When the booster pumps 41 are installed in parallel, the cooling water is pumped simultaneously by multiple booster pumps 41, so that the load on each booster pump 41 can be divided.

[0052] The backup heater 42 heats at least a portion of the cooling water transferred to the heat exchanger 30. The backup heater 42 heats the cooling water using a separate heat source so that the cooling water has a temperature sufficient to heat the liquefied gas in the heat exchanger 30. In this case, the heat source may be, but is not limited to, seawater, fresh water, steam, etc.

[0053] The backup heater 42 may be provided in case the temperature of the cooling water drops as the load on the main engine E1 decreases, resulting in insufficient heat to sufficiently heat the liquefied gas in the heat exchanger 30, or the temperature of the cooling water drops due to the outside air temperature, or the main engine E1 stops and the cooling water cannot be heated.

[0054] The backup heater 42 may be disposed downstream of the booster pump 41 on the cooling water circulation line L20, but the position of the backup heater 42 is not limited to this and it may be provided on the first branch line L21 described later.

[0055] The gas separator 43 separates gases that may be contained in the low-temperature cooling water discharged from the heat exchanger 30. The gas separator 43 may be installed downstream of the heat exchanger 30 in the cooling water circulation line L20, and can detect and separate gases if they leak from the heat exchanger 30 and get mixed into the cooling water. To this end, the gas separator 43 may be equipped with a gas detector (not shown), and since the gas separated by the gas separator 43 is explosive, it can be safely released to the outside via the vent line L25.

[0056] If the gas separator 43 detects that gas has been mixed into the cooling water, the supply of liquefied gas to the heat exchanger 30 can be cut off to prevent further leakage of liquefied gas, and the engines E1, E2 can be stopped or switched to a mode that consumes non-liquefied gas fuel, such as oil fuel. For the latter, the engines E1, E2 can be dual-fuel engines that can use both gas fuel and / or oil fuel.

[0057] The gas separator 43 may be disposed between the heat exchanger 30 and the booster pump 41 in the cooling water circulation line L20, and may have the form of a container for storing cooling water, thereby allowing the gas separator 43 to have a partial expansion function in the cooling water circulation line L20.

[0058] The cooling water circulation line L20 and the first and second branch lines L21 and L22 will be described below.

[0059] The cooling water circulation line L20 is provided to circulate and supply cooling water to the main engine E1 and the heat exchanger 30. After the cooling water is discharged from the main engine E1 at a high temperature, it is cooled to a low temperature by heat exchange with liquefied gas in the heat exchanger 30 and can be circulated to the main engine E1 again.

[0060] In this case, the cooling water circulation line L20 is provided with a first branch line L21 that connects both ends of the first cooling water circulation line L20a to connect the upstream and downstream of the heat exchanger 30, allowing the cooling water to circulate through the heat exchanger 30 while bypassing the main engine E1.

[0061] In addition, the cooling water circulation line L20 is provided with a second branch line L22 that connects both ends of the second cooling water circulation line L20b of the cooling water circulation line L20 to connect the upstream and downstream of the main engine E1, allowing the cooling water to circulate through the main engine E1 while bypassing the heat exchanger 30.

[0062] In this case, the first and second branch lines L21, L22, together with the first and second cooling water circulation lines L20a, L20b, can form first and second closed loops that are provided independently of each other. By configuring in this way, the cooling water can circulate along a total of three closed loops.

[0063] Specifically, the cooling water can circulate along the entire cooling water circulation line L20 and pass through the heat exchanger 30 and the main engine E1, or circulate along the first cooling water circulation line L20a and the first branch line L21 and bypass the main engine E1 and pass through the heat exchanger 30, or circulate along the second cooling water circulation line L20b and the second branch line L22 and bypass the heat exchanger 30 and pass through the main engine E1.

[0064] If there is no problem with the operation of the main engine E1 and the heat exchanger 30, the first and second branch lines L21 and L22 may both be closed, and the coolant circulates widely along the entire coolant circulation line L20. Therefore, the coolant repeats the process of being heated by the main engine E1 and cooled by the heat exchanger 30.

[0065] In particular, in this case, the coolant can be heated to a sufficient temperature by the main engine E1 operating at normal load, eliminating the need for additional heating by the backup heater 42. Therefore, the coolant circulation line L20 may be provided with a heater bypass line L23 that bypasses the backup heater 42 when the coolant is supplied to the heat exchanger 30 through the coolant circulation line L20 and the main engine E1.

[0066] However, if the load on the main engine E1 drops below a preset value, the main engine E1 may not be able to heat the coolant sufficiently. In this case, the heater bypass line L23 may be blocked and the backup heater 42 may be used.

[0067] On the other hand, when the coolant cannot circulate through the main engine E1 or there is little need for it to circulate, such as when the main engine E1 is stopped, the present invention opens the first branch line L21 so that the coolant circulates through a first closed loop formed along the first coolant circulation line L20a and the first branch line L21.

[0068] In this case, valves (symbols not shown) capable of blocking the flow of cooling water are installed downstream of the point where the first branch line L21 branches off from the cooling water circulation line L20 and upstream of the point where the first branch line L21 joins, so that the cooling water can be circulated within the first closed loop.

[0069] The first closed loop is provided with a booster pump 41, a backup heater 42, a heat exchanger 30, and a gas separator 43, and the cooling water is heated by the backup heater 43 before being supplied to the heat exchanger 30. Therefore, the present invention can ensure stable heating of the liquefied gas in the heat exchanger 30 even when the cooling water does not or cannot circulate through the main engine E1.

[0070] As a result, in a system in which the main engine E1 and the auxiliary engine E2 share one heat exchanger 30, the present invention allows the auxiliary engine E2 to operate stably even if a problem occurs in heating the coolant by the main engine E1.

[0071] On the other hand, when it is not desirable to use the heat exchanger 30, such as when a gas leak is detected in the gas separator 43 or when a fuel other than liquefied gas is supplied to the engines E1 and E2, the present invention opens the second branch line L22 so that the cooling water circulates in a second closed loop formed along the second cooling water circulation line L20b and the second branch line L22.

[0072] At this time, as described above, the cooling water can be circulated within the second closed loop by operating the valves provided upstream of the point where the second branch line L22 branches off from the cooling water circulation line L20 and upstream of the point where the second branch line L22 joins.

[0073] For reference, the valve installed downstream of the point where the first branch line L21 branches off from the cooling water circulation line L20 may be a valve installed upstream of the point where the second branch line L22 joins the cooling water circulation line L20, and the valve installed upstream of the point where the first branch line L21 joins the cooling water circulation line L20 may be a valve installed downstream of the point where the second branch line L22 branches off from the cooling water circulation line L20.

[0074] Of course, the present invention is not limited to the above-described valve arrangement, and two-way valves and / or three-way valves may be used as appropriate.

[0075] A cooling water pump 21, a cooling water cooler 22, and a fresh water generator 23 are provided on the second closed loop, and the cooling water can be heated by the main engine E1 and then cooled by the cooling water cooler 22. Therefore, the present invention can ensure the supply of cooling water to the main engine E1 and maintain stable operation of the main engine E1 even when the cooling water is not or cannot be transferred to the heat exchanger 30.

[0076] The cooling water circulation line L20 is connected to expansion tanks 44a and 44b, which may be provided to adjust the pressure of the cooling water flowing along the entire cooling water circulation line L20.

[0077] A plurality of expansion tanks 44a, 44b are provided and connected to the first and second closed loops formed by the first and second branch lines L21, L22, respectively, to adjust the pressure of the cooling water in the first and second closed loops and prevent overpressure in the first and second closed loops. Alternatively, one expansion tank 44a, 44b may be integrally connected to the first and second closed loops.

[0078] In the former case, the expansion tanks 44a and 44b may be connected to the first and second coolant circulation lines L20a and L20b, respectively. In this case, the expansion tank 44a connected to the first coolant circulation line L20a may be installed downstream of the gas separator 43 in the coolant circulation line L20, and by being branched off and connected from the coolant circulation line L20, the coolant that has passed through the gas separator 43 can flow without passing through the expansion tank 44a. However, if the pressure of the coolant increases downstream of the gas separator 43, the coolant can be naturally transferred toward the expansion tank 44a, thereby reducing the pressure by the expansion tank 44a.

[0079] Meanwhile, the expansion tank 44b connected to the second coolant circulation line L20b may be installed between the coolant cooler 22 and the coolant pump 21, and is branched off from the coolant circulation line L20, so that the coolant cooled in the coolant cooler 22 can bypass the expansion tank 44b and flow into the coolant pump 21. However, if overpressure occurs in the second closed loop, the coolant is transferred to the expansion tank 44b, so that the inflow pressure of the coolant pump 21 can be maintained at an appropriate level.

[0080] The expansion tanks 44a, 44b may be branched off and connected to the cooling water circulation line L20 or the first and second branch lines L21, L22, or may be provided on the cooling water circulation line L20 or the first and second branch lines L21, L22. The expansion tanks 44a, 44b are not necessarily limited to a container shape, and may be in any shape that provides a buffer function, such as a shape in which a part of the line is expanded.

[0081] By providing such expansion tanks 44a, 44b, the present invention can ensure overpressure prevention function for the flow of cooling water both when the cooling water circulates only in the first closed loop and when the cooling water circulates only in the second closed loop.

[0082] Furthermore, the cooling water circulation line L20 upstream of the heat exchanger 30 may be provided with a heat exchanger bypass line L24 that bypasses the heat exchanger 30. Therefore, at least a portion of the cooling water can bypass the heat exchanger 30 and not be cooled by the liquefied gas, and can be used to adjust the temperature of the cooling water downstream of the heat exchanger 30.

[0083] The flow to the heat exchanger bypass line L24 can be controlled depending on variables such as the flow rate and temperature of the liquefied gas, the flow rate and temperature of the cooling water, etc. For example, if the temperature of the liquefied gas is relatively high, some of the cooling water can be diverted via the heat exchanger bypass line L24 to prevent excessive heating of the liquefied gas. On the other hand, if the temperature of the liquefied gas is detected to be low, the flow of cooling water through the heat exchanger bypass line L24 can be shut off.

[0084] The various flows of cooling water shown in this embodiment will be described below. First, the case where cooling water flows along the cooling water circulation line L20 as shown in FIG.

[0085] 1, as described above, the coolant circulation line L20 forms a closed loop connecting both the main engine E1 and the heat exchanger 30, so that high-temperature coolant discharged from the main engine E1 can be transferred to the heat exchanger 30 via the coolant circulation line L20. Thereafter, the low-temperature coolant discharged from the heat exchanger 30 can flow along the coolant circulation line L20 through the gas separator 43 and the like, and then enter the coolant cooler 22.

[0086] According to this flow, the coolant flows along the coolant circulation line L20 into the coolant cooler 22, the coolant pump 21, and the main engine E1, and at least a portion of the coolant downstream of the main engine E1 flows along the coolant circulation line L20 through the booster pump 41, the backup heater 42 (if necessary), the heat exchanger 30, and the gas separator 43, and then can be transferred back to the coolant cooler 22.

[0087] This flow can be formed when the main engine E1 operates normally and the coolant is sufficiently heated by the main engine E1. That is, in this embodiment, high-temperature coolant heated via the main engine E1 is transferred to the heat exchanger 30 along the coolant circulation line L20, thereby transferring waste heat from the coolant to the liquefied gas in the heat exchanger 30.

[0088] To heat the cooling water sufficiently, the load of the main engine E1 must be higher than a preset value. That is, when the load of the main engine E1 is higher than a preset value (or when the ship's speed is higher than a preset speed), the cooling water can circulate along the entire cooling water circulation line L20. In this case, since the cooling water is sufficiently heated by the main engine E1, the cooling water in the cooling water circulation line L20 can at least partially bypass the backup heater 42 via the heater bypass line L23 and flow into the heat exchanger 30.

[0089] On the other hand, when the load of the main engine E1 is less than a preset value (the boat speed is less than a preset speed), the cooling water may not be sufficiently heated even when passing through the main engine E1. Therefore, in this case, the cooling water circulates along the cooling water circulation line L20, similar to the case described above, but the cooling water flowing through the cooling water circulation line L20 can be additionally heated through the backup heater 42 before flowing into the heat exchanger 30.

[0090] In the following, a case where the cooling water flows along the first closed loop formed by the cooling water circulation line L20 and the first branch line L21 as shown in FIG. 2 will be described.

[0091] 2, when the main engine E1 is stopped due to the ship being docked, cooling water may not flow through the cooling water circulation line L20. In this case, the first branch line L21 is opened by adjusting a valve, and the cooling water flows through the first closed loop formed by the first cooling water circulation line L20a and the first branch line L21.

[0092] In this case, however, since the coolant is not heated by the main engine E1, a backup heater 42 may be used. That is, the coolant circulates along the first coolant circulation line L20a and the first branch line L21, is heated by the backup heater 42, and then flows into the heat exchanger 30.

[0093] In this case, as described above, the pressure of the cooling water can be adjusted via expansion tanks 44a, 44b provided downstream of the gas separator 43 in the cooling water circulation line L20, etc., so that the heat exchanger 30 can stably heat the liquefied gas using the cooling water without using waste heat from the main engine E1.

[0094] In this way, in this embodiment, the cooling water of the main engine E1 is used to heat the liquefied gas supplied to engines E1 and E2, but by controlling the flow of the cooling water depending on the load on the main engine E1 and whether it is operating or not, and by appropriately utilizing the backup heater 42, the liquefied gas can be heated stably, ensuring stable operation of the power generation engine.

[0095] The present invention has been described in detail above with reference to specific examples. However, these examples are for the purpose of specifically explaining the present invention, and the present invention is not limited thereto. It is clear that modifications and improvements can be made by those skilled in the art within the technical spirit of the present invention.

[0096] Any simple variations or modifications of the present invention fall within the scope of the present invention, and the specific scope of protection of the present invention will be made clear by the appended claims.

Claims

1. a fuel supply line that supplies fuel to the main engine; a heat exchanger provided in the fuel supply line for heating the fuel; a cooling water circulation line for the main engine, the cooling water circulation line being provided to supply a heat source to the heat exchanger; The cooling water circulation line is a first cooling water circulation line for circulating the heat exchanger and a second cooling water circulation line for circulating the main engine;

2. a first branch line connecting both ends of the first cooling water circulation line so that the cooling water bypasses the main engine and circulates through the heat exchanger; 2. The gas processing system of claim 1, further comprising: a second branch line connecting both ends of the second cooling water circulation line so that the cooling water bypasses the heat exchanger and circulates through the main engine.

3. a backup heater provided in the first cooling water circulation line or the first branch line, The backup heater is 3. The gas processing system of claim 2, wherein when the load of the main engine is less than a preset value or when the cooling water bypasses the main engine through the first branch line, the cooling water is heated and supplied to the heat exchanger.

4. 4. The gas processing system of claim 3, further comprising a bypass line configured to bypass the backup heater when cooling water is supplied to the heat exchanger via the main engine through the cooling water circulation line.

5. The first branch line is 3. The gas processing system of claim 2, wherein when said primary engine is shut down, cooling water bypasses said primary engine and circulates through said heat exchanger.

6. The cooling water is circulating along the entire cooling water circulation line and passing through the heat exchanger and the main engine; circulating the cooling water along the first cooling water circulation line and the first branch line, bypassing the main engine and passing through the heat exchanger; 3. The gas processing system according to claim 2, wherein the cooling water circulates along the second cooling water circulation line and the second branch line, bypassing the heat exchanger and passing through the main engine.

7. a first closed loop formed by the first cooling water circulation line and the first branch line, 7. The gas processing system according to claim 6, wherein the second closed loop formed by the second cooling water circulation line and the second branch line is provided independently.

8. 8. The gas processing system of claim 7, further comprising an expansion tank for adjusting the pressure of the cooling water flowing along the first closed loop or the second closed loop.

9. A ship comprising the gas processing system according to any one of claims 1 to 8.

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