JP6843099B2 - Evaporative gas treatment equipment and treatment method for ships - Google Patents

Description

The present invention relates to a ship's evaporative gas treatment device and a treatment method, and more particularly to a ship's evaporative gas treatment device and a treatment method capable of effectively treating the evaporative gas generated in a ship's storage tank. ..

As the International Maritime Organization (IMO) regulations on the emission of greenhouse gases and various air pollutants are tightened, the shipbuilding and shipping industries will use natural gas as a clean energy source instead of using existing fuels such as heavy oil and light oil. Gas is often used as fuel gas for ships.

Natural Gas is usually a liquefied natural gas that is a clear, colorless, ultra-low temperature liquid that has been cooled to approximately -162 degrees Celsius to reduce its volume to 1/600 for ease of storage and transportation. (Liquefied Natural Gas) has changed phase to carry out management and operation.

Such liquefied natural gas is stored and transported in a storage tank that is heat-insulated and installed on the hull. However, since it is virtually impossible to completely insulate and store liquefied natural gas, external heat is continuously transferred to the inside of the storage tank, and liquefied natural gas is naturally vaporized and generated. Evaporative gas accumulates inside the storage tank. Evaporative gas must be treated and removed as it can increase the internal pressure of the storage tank and induce deformation and damage to the storage tank.

Therefore, conventionally, a method of flowing evaporative gas through a vent mast provided on the upper side of the storage tank or burning evaporative gas using GCU (Gas Combustion Unit) has been used. However, this is not preferable in terms of energy efficiency, so the evaporative gas is supplied together with the liquefied natural gas or as fuel gas to the engine of the ship, or the evaporative gas is reliquefied using a reliquefaction device consisting of a refrigeration cycle or the like. A plan to let them use it is being used.

On the other hand, natural gas is a mixture containing ethane, propane, butane, nitrogen, and the like in addition to methane. Of these, the boiling point of nitrogen is about -195.8 degrees Celsius, which is much lower than the other components such as methane (boiling point -161.5 degrees Celsius) and ethane (boiling point -89 degrees Celsius).

Along with this, the evaporative gas generated by spontaneous vaporization inside the storage tank contains a large amount of nitrogen component having a relatively low boiling point, which causes a decrease in the reliquefaction efficiency of the evaporative gas and utilizes the evaporative gas. And affect processing.

Further, when the evaporative gas is supplied to the engine of a ship as a fuel gas, the nitrogen component of the evaporative gas affects the decrease in the calorific value of the fuel gas. Although it will be improved, a plan that can efficiently cite and manage fuel gas is required.

An embodiment of the present invention attempts to provide a ship's evaporative gas treatment apparatus and treatment method capable of improving the reliquefaction efficiency of the evaporative gas and achieving efficient use of the evaporative gas.

An embodiment of the present invention is intended to provide a ship's evaporative gas treatment device and treatment method capable of effectively adjusting and maintaining the calorific value of the fuel gas supplied to the engine and achieving efficient equipment operation with a simple structure. To do.

Embodiments of the present invention seek to provide ship evaporative gas treatment devices and treatment methods that can improve energy efficiency.

According to one aspect of the present invention, the gas is pressurized through a storage tank that houses the liquefied gas and the evaporative gas, an evaporative gas supply line that includes a compression unit that pressurizes the evaporative gas of the storage tank, and the compression unit. A nitrogen separator that separates the evaporative gas into a flow of a first gas containing a first concentration of nitrogen component and a flow of a second gas containing a second concentration of nitrogen component, the first consumption of the flow of the first gas. It may be provided including a first fuel gas supply line for supplying the means and a reliquefaction line for receiving and reliquefying the flow of the second gas.

The nitrogen separator may be provided including a membrane filter.

The reliquefaction line reduces the pressure of the heat exchange section that exchanges heat with the evaporative gas in the previous stage of the compression section and the flow of the second gas that has passed through the heat exchange section and exchanged heat. An expansion valve, a gas-liquid separator that separates the flow of the second gas that has passed through the expansion valve and is decompressed into a gas component and a liquid component, and a flow of the second gas that is separated by the gas-liquid separator. The gas component of the liquefied gas recovery line for supplying the liquid component of the above to the storage tank and the gas component of the flow of the second gas separated by the gas-liquid separator is supplied to the storage tank or the stage before the compression unit on the evaporative gas supply line. It may be provided including an evaporative gas circulation line.

A second fuel gas supply line that is branched from the middle portion of the compression unit and supplies the evaporative gas pressurized by the compression unit to the second consuming means or the GCU (Gas Combustion Unit) may be further provided.

An evaporative gas supply line that provides the evaporative gas contained in the storage tank to the evaporative gas consumption means, a compression unit provided in the evaporative gas supply line to pressurize the evaporative gas, and a branch from the evaporative gas supply line. A reliquefaction line that reliquefies the flowing evaporative gas, a heat exchange unit that exchanges heat between the reliquefaction line and the evaporative gas supply line; and an evaporative gas provided in the reliquefaction line before entering the heat exchange unit. May include a reliquefaction swelling portion that swells the gas.

It may be further provided with an expansion valve that depressurizes the evaporative gas that has passed through the heat exchange section, and a gas-liquid separator that separates the reliquefied evaporative gas that has passed through the expansion valve into a gas component and a liquid component. ..

The reliquefaction line is a liquefied gas recovery line that supplies the liquid component separated by the gas-liquid separator to the storage tank and a gas component separated by the gas-liquid separator on the storage tank or the evaporative gas supply line. The evaporative gas circulation line supplied to the pre-stage of the compression unit of the above may be further included.

The reliquefaction expansion unit may be provided so as to reduce the pressure of the evaporative gas branched and flowing from the evaporative gas supply line to 50 bar to 160 bar.

The reliquefaction expansion portion may be provided so that the degree of depressurization of the evaporative gas branched from the evaporative gas supply line differs depending on the content of the nitrogen component of the evaporative gas in the storage tank.

When the content of the nitrogen component of the evaporative gas in the storage tank is 10 mole%, the reliquefaction expansion unit reduces the evaporative gas branched from the evaporative gas supply line to 140 bar to 160 bar and reduces the pressure in the storage tank to 140 bar to 160 bar. When the content of the nitrogen component of the evaporative gas is 0 mole%, the evaporative gas branched from the evaporative gas supply line may be reduced to 50 bar to 70 bar.

The reliquefaction expansion unit may be provided so that the degree of expansion of the evaporative gas branched from the evaporative gas supply line and flowing may be different, and may be provided so as to adjust the pressure of the evaporative gas entering the heat exchange unit.

In a ship's evaporative gas treatment method for treating evaporative gas using a ship's evaporative gas treatment device, the flow rate of the evaporative gas supply line is measured, and the degree of decompression of the reliquefaction expansion portion is increased in one direction (increased). If the flow rate measured in the evaporative gas supply line becomes large when adjusted in the direction (direction or decreasing direction), the degree of decompression of the reliquefaction expansion part is adjusted in another direction, and the decompression of the reliquefaction expansion part is reduced. When the degree is adjusted in any one direction (increase direction or decrease direction), if the flow rate measured by the evaporative gas supply line becomes smaller, the degree of decompression of the reliquefaction expansion portion is continued in the one direction. Can be provided to adjust.

It may be provided so that the pressure of the evaporative gas depressurized through the reliquefaction expansion section is adjusted to a target pressure that minimizes the flow rate measured at the evaporative gas supply line.

As the amount of liquefied gas stored in the storage tank changes, the target pressure of the evaporated gas decompressed through the reliquefaction expansion unit changes, and the degree of decompression of the reliquefaction expansion unit is adjusted to the changed target pressure. Can be provided to do so.

The ship's evaporative gas treatment apparatus and treatment method according to the embodiment of the present invention have the effect of improving the reliquefaction efficiency and performance of the evaporative gas and efficiently utilizing and managing the evaporative gas.

The ship's evaporative gas treatment apparatus and treatment method according to the embodiment of the present invention have the effect of effectively adjusting and maintaining the calorific value of the fuel gas and improving energy efficiency.

The ship's evaporative gas treatment device and treatment method according to the embodiment of the present invention have an effect of achieving efficient equipment operation with a simple structure.

The conceptual diagram which shows the evaporative gas processing apparatus of a ship by 1st Embodiment of this invention. The conceptual diagram which shows the evaporative gas processing apparatus of a ship by 2nd Embodiment of this invention. The conceptual diagram which shows the evaporative gas processing apparatus of a ship according to 3rd Example of this invention. The conceptual diagram which shows the evaporative gas processing apparatus of a ship according to 4th Embodiment of this invention. The graph which shows the correlation between the mass flow rate of the evaporative gas entering a compression part by the pressure of the evaporative gas entering a heat exchange part, and the energy required by a compression part. The graph which shows the correlation of the mass flow rate of the evaporative gas to be reliquefied by the mass flow rate of the evaporative gas required by the evaporative gas consumption means. The graph which shows the correlation of the mass flow rate of the evaporative gas entering the compression part by the mass flow rate of the evaporative gas required by the evaporative gas consumption means. The graph which shows the correlation of the energy required in the compression part by the mass flow rate of the evaporative gas required by the evaporative gas consumption means. The graph which shows the correlation of the mass flow rate of the flash gas by the pressure of the evaporative gas entering the heat exchange part. The graph which shows the correlation of the mass flow rate of the flash gas by the pressure of the evaporative gas entering the heat exchange part.

Hereinafter, examples of the present invention will be described in detail with reference to the accompanying drawings. The following examples are presented in order to fully convey the idea of the present invention to a person who has ordinary knowledge in the technical field to which the present invention belongs. The present invention is not limited to the examples presented herein, but may be embodied in other embodiments. In order to clarify the present invention, the drawings may omit the illustration of parts not related to the explanation, and the size of the components may be exaggerated to help understanding.

In the description of the ship's evaporative gas treatment apparatus and treatment method according to the embodiments of the present invention, the ship can be understood in the sense that it includes various marine structures. Vessels include not only liquefied gas transport vessels that transport liquefied gas, but also marine structures of various structures that can be propelled or generated using liquefied gas as fuel. Further, any form of liquefied gas that can be used as fuel can be included in the ship of the present invention. As an example, it should be understood by a concept that includes all vessels such as LNG carriers and LNG RVs, as well as marine plans such as LNG FPSO and LNG FSRU.

Further, in the description of the ship's evaporative gas treatment apparatus and treatment method according to the present embodiment, as an example for assisting the understanding of the present invention, liquefied natural gas and evaporative gas generated from the liquefied natural gas have been applied, but the description is limited to this. It should be understood as the same technical idea when various liquefied gases such as liquefied ethane gas and liquefied hydrocarbon gas and the evaporative gas generated from the gas are applied.

FIG. 1 is a conceptual diagram showing a ship's evaporative gas treatment device 100 according to the first embodiment of the present invention.

Referring to FIG. 1, the ship's evaporative gas treatment apparatus 100 according to the first embodiment of the present invention includes a storage tank 110, an evaporative gas supply line 120 including a compression unit 121 for pressurizing the evaporative gas of the storage tank 110, and compression. The flow of the nitrogen separator 130 for separating the nitrogen component contained in the evaporative gas pressurized by the unit 121 and the first gas containing the first concentration nitrogen component separated by the nitrogen separator 130 is the first consuming means. Branch from the middle stage of the first fuel gas supply line 150 supplied to 11, the reliquefaction line 140 for reliquefying the flow of the second gas containing the second concentration nitrogen component separated by the nitrogen separator 130, and the compression unit 121. The fuel supplied to the second consumption means 12, the second fuel gas supply line 170, and the first consumption means 11 that supply the evaporative gas partially pressurized by the compression unit 121 to the second consumption means 12 or the GCU 15 (Gas Communication Unit, 15). It may include a calorific value adjusting unit 160 that measures and adjusts the calorific value of the gas.

In the following examples, liquefied natural gas and evaporative gas generated from the liquefied natural gas have been applied and described as an example for assisting the understanding of the present invention, but the present invention is not limited to this, and liquefied ethane gas, liquefied hydrocarbon gas, etc. It should be understood as the same technical idea when various liquefied gases and evaporative gases generated from the above are applied.

The storage tank 110 is provided to store or store liquefied natural gas and evaporative gas generated from the liquefied natural gas. The storage tank 110 may be provided in a membrane-type cargo hold that has been heat-insulated to minimize vaporization of liquefied natural gas due to external heat intrusion. The storage tank 110 receives and stores liquefied natural gas from a natural gas producing area or the like, stores or stores the liquefied natural gas, and stably stores the liquefied natural gas and the evaporative gas until it arrives at the destination and is unloaded. Can be provided for use in fuel gas such as a ship's propulsion consumption means or a ship's power generation consumption means.

The storage tank 110 is generally installed with heat insulation treatment, but since it is practically difficult to completely block external heat intrusion, liquefied natural gas naturally evaporates and evaporates inside the storage tank 110. There is gas. Since such an evaporative gas raises the internal pressure of the storage tank 110 and has a potential risk of deformation and explosion of the storage tank 110, it is necessary to remove or treat the evaporative gas from the storage tank 110. Along with this, the evaporative gas generated inside the storage tank 110 is used as the fuel gas of the evaporative gas consuming means by the first fuel gas supply line 150 or the second fuel gas supply line 170 as in the embodiment of the present invention. It can be reliquefied or reliquefied by the reliquefaction line 140 and resupplied to the storage tank 110. Further, although not shown, it is also possible to supply the evaporative gas to a vent mast (not shown) provided on the upper part of the storage tank 110 to process or consume the evaporative gas.

The evaporative gas consuming means can supply fuel gas such as liquefied natural gas and evaporative gas contained in the storage tank 110 to generate propulsive force for the ship, or generate a power source for power generation such as internal equipment of the ship. The evaporative gas consuming means includes a first consuming means 11 that receives a relatively high pressure fuel gas and generates an output, and a second consuming means 12 that receives a relatively low pressure fuel gas and generates an output. Can be done. As an example, the first consuming means 11 is composed of a ME-GI engine or an X-DF engine capable of generating an output with a relatively high pressure fuel gas, and the second consuming means 12 is composed of a relatively low pressure fuel gas. It can be configured with a DFDE engine or the like that can generate output with. However, it is not limited to this, and it should be understood equally when various numbers of engines and various kinds of consumption means are utilized.

The evaporative gas supply line 120 pressurizes the evaporative gas existing in the storage tank 110 and supplies it as fuel gas to the second consumption means 12, or supplies it to the first consumption means 11 and the reliquefaction line 140 via the nitrogen separator 130. Can be provided to do so. The evaporative gas supply line 120 is provided with the inlet side end connected to the inside of the storage tank 110, and the outlet side end is connected to the first fuel gas supply line 150 and the reliquefaction line 140 via the nitrogen separator 130 described later. Can be provided to be. The evaporative gas supply line 120 is provided with a compression unit 121 including a plurality of stages of compressors 121a so that the evaporative gas can be processed according to the conditions required by the first consuming means.

The compression unit 121 can include a compressor 121a that compresses the evaporative gas and a cooler 121b that cools the evaporative gas that is heated while being compressed. When the evaporative gas consuming means includes a plurality of engines having different pressure conditions, the second fuel gas supply line 170 described later is branched from the middle part of the compression unit 121 to the second consuming means 12 or the GCU 15. It may be provided to supply a partially pressurized evaporative gas.

As will be described later, the pressure of the evaporative gas pressurized by the compression unit 121 may decrease while passing through the nitrogen separator 130. Therefore, the first consuming means 11 requires the compression unit 121 in consideration of this. It may be provided to pressurize and supply the evaporative gas at a pressure that is a predetermined magnitude higher than the fuel gas pressure condition.

In FIG. 1, the compression unit 121 is shown to consist of a five-stage compressor 121a and a cooler 121b, but this is only an example, and the compression unit 121 has various numbers of compressors according to the required pressure conditions and temperature of the engine. It may consist of 121a and a cooler 121b. Further, a heat exchange section 141 of the reliquefaction line 140, which will be described later, may be installed in front of the compression section 121 on the evaporative gas supply line 120, and a detailed description thereof will be described later.

The nitrogen separator 130 may be provided at the outlet side end of the evaporative gas supply line 120 so as to pass through the compression section 121 and separate the nitrogen component contained in the pressurized evaporative gas. The nitrogen separator 130 classifies the pressurized evaporative gas into a flow of a first gas containing a first concentration of nitrogen component and a flow of a second gas containing a relatively second concentration of nitrogen component, and first. The gas flow is provided so as to be supplied to the first fuel gas supply line 150 so that the first consumption means 11 can be used as fuel gas, and the second gas flow is supplied to the reliquefaction line 140 described later.

The first concentration nitrogen component and the second concentration nitrogen component described in this example mean a high concentration nitrogen component and a low concentration nitrogen component, respectively, and the first concentration nitrogen component is a second concentration. It has a relatively high concentration of nitrogen component as compared with the nitrogen component of the above, and the second concentration nitrogen component has a relatively low concentration nitrogen component as compared with the first concentration nitrogen component. The first concentration and the second concentration are not limited to specific numerical values, and should be understood as a relative meaning due to the difference in concentration between the first concentration and the second concentration.

Natural gas is a mixture containing ethane, propane, butane, nitrogen, and the like in addition to methane, which is the main component. Of these, the boiling point of nitrogen is about -195.8 degrees Celsius, which is much lower than the other components such as methane (boiling point -161.5 degrees Celsius) and ethane (boiling point -89 degrees Celsius). Along with this, the natural evaporative gas generated by spontaneous vaporization inside the storage tank 110 vaporizes a large amount of nitrogen components having a low boiling point and contains a large amount of nitrogen components. When trying to reliquefy such an evaporative gas, it is very difficult to reliquefy the nitrogen component because the boiling point is low, and the reliquefaction efficiency decreases as the concentration of the nitrogen component of the evaporative gas increases.

Therefore, the nitrogen separator 130 passes through the evaporative gas supply line 120 to separate the nitrogen component contained in the pressurized evaporative gas, and the flow of the first gas containing the first concentration nitrogen component is the first. Although it is supplied as the fuel gas of the consuming means 11, by supplying the nitrogen component of the second concentration to the reliquefaction line 140, the evaporative gas reliquefaction performance and efficiency of the reliquefaction line 140 can be improved.

The nitrogen separator 130 may consist of a membrane filter. The membrane filter comprises a substance having a high affinity with the nitrogen component, and the pressurized evaporative gas passes through the membrane filter by the pressure, so that the nitrogen component is filtered by the membrane filter and the first fuel gas supply line 150 The non-nitrogen component such as methane can pass through as it is and be supplied to the reliquefaction line 140.

The first fuel gas supply line 150 is provided so as to supply the flow of the first gas containing the nitrogen component of the first concentration separated by the nitrogen separator 130 to the first consumption means 11 as the fuel gas. As described above, the pressurized evaporative gas passes through the nitrogen separator 130 and has a flow of a first gas containing a first concentration nitrogen component having a relatively high concentration and a second concentration having a relatively low concentration. When separated into the flow of the second gas containing the nitrogen component of the above, the first fuel gas supply line 150 receives the flow of the first gas having a low reliquefaction efficiency and feeds the first consumption means 11 as a fuel gas. By supplying and using the fuel gas, it is possible to efficiently use the fuel gas and increase the reliquefaction efficiency of the second gas flow.

The reliquefaction line 140 is provided so as to be separated by the nitrogen separator 130 and supplied with a flow of a second gas containing a nitrogen component having a second concentration to be reliquefied. The higher the nitrogen content of the evaporative gas to be reliquefied, the lower the reliquefaction efficiency of the evaporative gas due to the lower boiling point of the nitrogen component. It is provided so as to receive the flow of the contained second gas and reliquefy it, and the reliquefaction efficiency of the evaporative gas can be improved.

The reliquefaction line 140 includes a heat exchange unit 141 that heat exchanges and cools the flow of the second gas separated by the nitrogen separator 130, an expansion valve 142 that reduces the pressure of the second gas flow that has passed through the heat exchange unit 141, and an expansion valve. A gas-liquid separator 143 that accommodates the flow of the second gas that has passed through 142 and is decompressed, a liquefied gas recovery line 144 that resupplyes the liquid component separated by the gas-liquid separator 143 to the storage tank 110, and gas-liquid separation. The evaporative gas circulation line 145 that re-supplies the gas component separated by the vessel 143 to the storage tank 110 or the evaporative gas supply line 120 side can be included.

The heat exchange unit 141 is provided so that the flow of the second gas supplied to the reliquefaction line 140 and the evaporative gas in the first stage of the compression unit 121 transferred along the evaporative gas supply line 120 exchange heat with each other. Since the flow of the second gas is in a state of being pressurized by the compression unit 121 to increase the temperature and pressure, the flow of the second gas is exchanged with each other by the low temperature evaporative gas before passing through the compression unit 121 of the evaporative gas supply line 120. , The flow of the pressurized second gas flowing along the reliquefaction line 140 can be cooled. In this way, even if there is no separate cooling device, the flow of the second gas pressurized through the compression unit 121 and the nitrogen separator 130 is exchanged with the low-temperature evaporative gas passing through the evaporative gas supply line 120. Since it can be cooled, wasteful use of the power source can be prevented, the equipment can be simplified, and the efficiency of equipment operation can be improved.

The expansion valve 142 may be provided after the heat exchange section 141. The expansion valve 142 sequentially passes through the compression unit 121, the nitrogen separator 130, and the heat exchange unit 141 to depressurize the flow of the pressurized and cooled second gas, and additionally cool and expand the flow of the second gas. Can be reliquefied. As an example, the expansion valve 142 may be composed of a Joule-Thomson valve.

The gas-liquid separator 143 accommodates the flow of the second gas that has been cooled and depressurized and reliquefied while passing through the expansion valve 142 so as to separate the liquid component and the gas component of the reliquefied second gas flow. It is provided in. Although most of the flow of the second gas is reliquefied when it passes through the expansion valve 142, there is a possibility that a gas component is generated due to the generation of flash gas in the process of depressurizing. Therefore, the separated liquid component of the flow of the second gas supplied to the gas-liquid separator 143 through the heat exchange unit 141 and the expansion valve 142 is resupplied to the storage tank 110 through the liquefied gas recovery line 144 described later. However, the separated gas component may be provided so as to be resupplied to the storage tank 110 or the evaporative gas supply line 120 by the evaporative gas circulation line 145 described later.

The liquefied gas recovery line 144 may be provided between the gas-liquid separator 143 and the storage tank 110 so as to resupply the liquid component of the evaporative gas separated by the gas-liquid separator 143 to the storage tank 110. The liquefied gas recovery line 144 may be provided with its inlet-side end communicating with the lower side of the gas-liquid separator 143 and its outlet-side end communicating with the inside of the storage tank 110. The liquefied gas recovery line 144 may be provided with an on-off valve (not shown) for adjusting the supply amount of the flow of the reliquefied second gas recovered in the storage tank 110.

The evaporative gas circulation line 145 separates the gas-liquid separator and the storage tank 110 or the gas-liquid so as to resupply the gas component of the evaporative gas separated by the gas-liquid separator 143 to the storage tank 110 or the evaporative gas supply line 120. It may be provided between the vessel 143 and the evaporative gas supply line 120. In FIG. 1, the evaporative gas circulation line 145 is shown in which the gas component inside the gas-liquid separator 143 is resupplied to the front stage of the compression unit 121 on the evaporative gas supply line 120, but in addition to this, gas-liquid separation is performed. This includes all cases where the container 143 is resupplied to the storage tank 110, or the evaporative gas supply line 120 and the storage tank 110 are resupplied together.

The second fuel gas supply line 170 is provided so as to be branched from the middle portion of the compression portion 121 of the first fuel gas supply line 150 so as to supply the partially pressurized evaporative gas to the second consumption means 12 or the GCU 15. It is provided in. The second fuel gas supply line 170 is provided so that the inlet side end is connected to the middle stage of the compression portion 121, the outlet side end is branched, one side is connected to the second consumption means 12, and the other side is connected to the GCU 15. Can be provided.

Since the second consuming means 12 is supplied with a relatively low-pressure fuel gas to generate an output, the second consuming means 12 is provided by being branched from the middle portion of the compression unit 121 that compresses the evaporation gas, so that the evaporation is partially pressurized. It can be operated by supplying and receiving gas as fuel gas. When the supply amount of the partially pressurized evaporative gas supplied through the second fuel gas supply line 170 is larger than the supply amount of the fuel gas required by the second consumption means 12, the GCU 15 is partially pressurized. It is provided so as to receive and consume the evaporated gas.

The calorific value adjusting unit 160 is provided so as to measure and adjust the calorific value of the fuel gas supplied to the first consumption means 11.

The heating value means the amount of heat released when a unit mass of fuel gas is completely burned. Of the natural gases, methane, butane and propane have relatively high calorific values, so components that increase the calorific value of fuel gas (methane calorific value: about 12,000 kcal / kg, butane calorific value: about 11,863 kcal /). Although the calorific value of kg and propane is about 2,000 kcal / kg), the calorific value of nitrogen is very low (calorific value of nitrogen: about 60 kcal / kg), so the absolute content or concentration of the nitrogen component is high. The lower the total calorific value of fuel gas. At this time, if the total calorific value of the fuel gas supplied to the evaporative gas consuming means is excessively low and the minimum calorific value required by the evaporative gas consuming means cannot be satisfied, the output of the evaporative gas consuming means is affected. This causes an unnecessary load on the means for consuming evaporative gas.

As described above, in order to increase the reliquefaction efficiency of the reliquefaction line 140, the flow of the second gas containing a low concentration nitrogen component among the pressurized evaporative gas is supplied to the reliquefaction line 140. Then, when the flow of the first gas is supplied to the first fuel gas supply line 150, the calorific value of the flow of the first gas is generated by the high concentration nitrogen component contained in the flow of the first gas, and the first consuming means 11 It may be lower than the required condition calorific value.

With reference to FIG. 1, the calorific value adjusting unit 160 of the evaporative gas treatment device 100 of the ship according to the first embodiment of the present invention measures or calculates the calorific value of the fuel gas supplied to the first consuming means 11. The calorific value riser line 162 for supplying the evaporative gas pressurized by the quantity measuring machine 161 and the compression unit 121 to the first fuel gas supply line 150 can be included.

The calorific value measuring machine 161 can measure the calorific value of the fuel gas including the flow of the first gas supplied to the first consumption means 11 in the first fuel gas supply line 150 in real time. The calorific value measuring machine 161 transmits the measured calorific value information of the fuel gas to a display unit (not shown) including a display or the like to notify the passengers of the ship of this, or the calorific value of the measured fuel gas. The information is transmitted to the control unit (not shown), and the control unit compares and analyzes the already input conditional calorific value of the first consumption means 11 and the calorific value information of the fuel gas transmitted from the calorific value measuring machine 161. It is possible to control the degree of opening and closing of the flow rate adjusting valve 163 provided in the calorific value increasing line 162, which will be described later.

Although it is shown in FIG. 1 that a calorific value measuring machine 161 is provided on the first fuel gas supply line 150 to measure the calorific value of the fuel gas, the calorific value of the fuel gas supplied to the first consuming means 11 is generated. If the quantity can be measured, its position can be deformed in various ways.

The calorific value rising line 162 may be provided with the inlet side end connected to the rear stage of the compression portion 121 on the evaporative gas supply line 120 and the outlet side end connected to the first fuel gas supply line 150. The calorific value rise line 162 joins the evaporated gas pressurized through the compression unit 121 with the flow of the first gas flowing through the first fuel gas supply line 150 as it is without passing through the nitrogen separator 130. To do. As a result, the flow of the first gas supplied to the first consuming means 11 and the concentration of the nitrogen component of the fuel gas composed of the pressurized evaporative gas are lowered, and the concentration of the components having a high calorific value such as methane and butane is reduced. It can be increased to increase the total calorific value of the fuel gas.

The calorific value rise line 162 may be provided with a flow rate adjusting valve 163 for adjusting the supply amount of the pressurized evaporative gas flowing along the calorific value rise line 162. The opening / closing degree of the flow rate adjusting valve 163 is automatically adjusted by the operator manually or by the control unit based on the calorific value information of the fuel gas measured by the calorific value measuring machine 161 and the conditional calorific value information of the first consuming means 11. It is possible to control the supply amount of the pressurized evaporative gas flowing along the calorific value rise line 162.

Hereinafter, the ship's evaporative gas treatment device 200 according to the second embodiment of the present invention will be described.

FIG. 2 is a conceptual diagram showing an evaporative gas treatment device 200 for a ship according to a second embodiment of the present invention. Referring to FIG. 2, the calorific value adjusting unit 260 of the evaporative gas treatment device 200 of the ship according to the second embodiment of the present invention is a calorific value measuring machine that measures or calculates the calorific value of the fuel gas supplied to the first consuming means. 261 Reliquefaction of the flow of the first gas supplied along the calorific value rise line 262 and the first fuel gas supply line 150 for supplying the evaporative gas pressurized by the compression unit 121 to the first fuel gas supply line 150. A calorific value adjusting line 264 circulated through the line 140 can be included.

In the description of the ship's evaporative gas treatment device 200 according to the second embodiment of the present invention described below, in addition to the configuration additionally described with a separate drawing number, the ship according to the first embodiment described above The description is the same as that for the evaporative gas processing apparatus 100, and the description is omitted in order to prevent duplication of contents.

The calorific value measuring machine 261 can measure the calorific value of the fuel gas including a part of the flow of the first gas supplied to the first consumption means to the first fuel gas supply line 150 in real time. The calorific value measuring machine 261 transmits the measured calorific value information of the fuel gas to a display unit (not shown) including a display or the like to notify the passengers of the ship of this, or the calorific value of the measured fuel gas. The information is transmitted to the control unit (not shown), and the control unit compares and analyzes the input conditional calorific value of the first consumption means and the calorific value information of the fuel gas transmitted from the calorific value measuring machine 261, which will be described later. It is possible to control the degree of opening and closing of each flow rate adjusting valve 263 and 265 provided in the calorific value rising line 262 or the calorific value adjusting line 264.

In FIG. 2, it is shown that a calorific value measuring machine 261 is provided on the first fuel gas supply line 150 to measure the calorific value of the fuel gas, but the calorific value of the fuel gas supplied to the first consuming means is shown. If it can be measured, its position can be deformed in various ways.

The calorific value rising line 262 may be provided with the inlet side end connected to the rear stage of the compression portion 121 on the evaporative gas supply line 120 and the outlet side end connected to the first fuel gas supply line 150. The calorific value rise line 262 joins the evaporated gas pressurized through the compression unit 121 with the flow of the first gas flowing through the first fuel gas supply line 150 as it is without passing through the nitrogen separator 130. To do. As a result, the concentration of the nitrogen component of the fuel gas supplied to the first consumption means can be lowered, the concentration of the component having a high calorific value such as methane and butane can be increased, and the total calorific value of the fuel gas can be increased. ..

The calorific value rise line 262 may be provided with a flow rate adjusting valve 263 that adjusts the supply amount of the pressurized evaporative gas flowing along the calorific value rise line 262. The opening / closing degree of the flow rate adjusting valve 263 is automatically adjusted manually by an operator or by a control unit based on the calorific value information of the fuel gas measured by the calorific value measuring machine 261 and the conditional calorific value information of the first consuming means. It is possible to control the supply amount of the pressurized evaporative gas flowing along the calorific value rise line 262.

The calorific value adjusting line 264 is provided so that the inlet side end is connected on the first fuel gas supply line 150, but is connected to the front stage of the point where the calorific value rising line 262 joins, and the outlet side end is re-established. It may be connected and provided on the liquefaction line 140. As described above, where the flow of the first gas contains a high concentration of nitrogen components, the calorific value is lower than that of the pressurized evaporative gas. Therefore, a part of the flow of the first gas flowing along the first fuel gas supply line 150 is circulated to the reliquefaction line 140 side to increase and adjust the total calorific value of the fuel gas supplied to the first consumption means. Can be done. At the same time, the calorific value adjusting line 264 recovers a part of the flow of the first gas to the reliquefaction line 140, so that the calorific value increasing line 262 is passed through in accordance with the required supply amount of the fuel gas of the first consuming means. It is possible to prevent an excessive increase in the total fuel gas supply amount due to the confluence of the pressurized evaporative gas, and to efficiently adjust the fuel gas supply amount.

The calorific value adjusting line 264 may be provided with a flow rate adjusting valve 265 that regulates the supply amount of a part of the flow of the first gas flowing along the calorific value adjusting line 264. The opening / closing degree of the flow rate adjusting valve 265 is automatically adjusted manually by an operator or by a control unit based on the calorific value information of the fuel gas measured by the calorific value measuring machine 261 and the conditional calorific value information of the first consuming means. It is possible to control the supply amount of a part of the flow of the first gas flowing along the calorific value adjusting line 264. Further, unlike this, although not shown, it is based on fuel gas supply amount information measured by a flow rate sensing unit (not shown) installed in the first fuel gas supply line 150 or the first consumption means. It is also possible to control the opening / closing degree l of the flow rate adjusting valve 265 provided in the calorific value adjusting line 264.

Hereinafter, the ship's evaporative gas treatment device 200 according to the third embodiment of the present invention will be described.

FIG. 3 is a conceptual diagram showing the ship's evaporative gas treatment device 300 according to the third embodiment of the present invention. With reference to FIG. 3, the ship's evaporative gas treatment device 300 according to the third embodiment of the present invention is stored. The evaporative gas supply line 320 for supplying the evaporative gas generated from the tank 310 to the evaporative gas consumption means 11 and 12, the reliquefaction line 330 for reliquefying a part of the evaporative gas passing through the evaporative gas supply line 320, and the storage tank 310. A liquefied gas supply line 340 that supplies the liquefied gas to the evaporative gas consuming means 11 and 12 can be included.

The evaporative gas supply line 320 is a flow path that provides the evaporative gas generated from the storage tank 310 to the evaporative gas consuming means 11 and 12.

One end of the evaporative gas supply line 320 is connected to the inside of the storage tank 310, and the other end is provided so as to merge with the liquefied gas supply line 340 described later and be connected to the evaporative gas consuming means 11 and 12. Then, the evaporative gas supply line 320 may be arranged on the upper side inside the storage tank 310 so that the evaporative gas supply line 320 can receive the evaporative gas inside the storage tank 310.

The storage tank 310 is provided to accommodate or store liquefied natural gas and evaporative gas. The storage tank 310 may be provided in a membrane-type cargo hold that has been heat-insulated to minimize vaporization of liquefied natural gas due to external heat intrusion. The storage tank 310 receives and stores liquefied natural gas from a natural gas producing area or the like, stores or stores the liquefied natural gas, and stably stores the liquefied natural gas and the evaporative gas until it arrives at the destination and is unloaded. It may be provided to be used as a fuel gas for a ship's propulsion engine or a ship's power generation engine.

The storage tank 310 can maintain an internal pressure of 1 bar to maintain the liquefied natural gas in a liquid state or a higher pressure in consideration of fuel supply conditions, and keep the internal temperature below -163 degrees. It can be provided so that it can be maintained.

The storage tank 310 is generally installed with heat insulation treatment, but since it is practically difficult to completely block heat intrusion from the outside, the evaporative gas generated by the natural vaporization of liquefied natural gas inside the storage tank 310. Exists. Since such evaporative gas has a potential risk of increasing the internal pressure of the storage tank 310 to deform or explode the storage tank 310, it is necessary to remove or dispose of the evaporative gas from the storage tank 310. ..

Along with this, the evaporative gas generated inside the storage tank 310 is consumed by the evaporative gas consuming means 11 and 12 by the evaporative gas supply line 320 or reliquefied by the reliquefaction line 330 as in the embodiment of the present invention. Can be resupplied to the storage tank 310.

Alternatively, although not shown in the drawing, unlike this, the evaporative gas is supplied to a vent mast (not shown) or a GCU (Gas Combustion Unit, not shown) provided on the upper part of the storage tank 310. Evaporative gas can also be additionally processed or consumed by. However, in the marine structure according to the embodiment of the present invention, instead of consuming the evaporative gas, the evaporative gas is provided to the evaporative gas consuming means 11 and 12 for efficient use, while the surplus evaporative gas is reliquefied. It can be returned to the storage tank 310.

Although one storage tank 310 is shown in the drawings, this is only shown for convenience, and the number and types of storage tanks 310 can be variously provided.

The evaporative gas consuming means 11 and 12 include an engine, a generator, a turbine and the like, and can produce energy and the like by using the evaporative gas as a raw material or using the evaporative gas. An engine using evaporative gas as a raw material receives fuel such as liquefied natural gas and / or evaporative gas contained in a storage tank 310 to generate propulsive force for the ship or generate a power source for power generation such as internal equipment of the ship. be able to.

As an example, the engine is a DFDE engine that can generate output with low pressure fuel (about 5 to 8 bar), an X-DF engine that can generate output with medium pressure fuel gas (about 15 to 20 bar), and high pressure. An ME-GI engine or the like capable of generating an output with the fuel gas (about 150 to 300 bar) of the above can be included. However, it is not limited to this, and it should be understood equally when various numbers of engines and various types of engines are used.

The evaporative gas consuming means 11 and 12 according to the third embodiment of the present invention include a first consuming means 11 that uses high-pressure natural gas and a second consuming means 12 that uses medium-pressure or low-pressure natural gas. As an example, the first consuming means 11 can be a ME-GI engine and the second consuming means 12 can be a DFDE engine.

The ship's evaporative gas treatment device 300 according to the third embodiment of the present invention includes a compression unit 321 provided in the evaporative gas supply line 320 to pressurize and cool the evaporative gas. Then, the compression unit 321 is provided on the evaporative gas supply line 320 in front of the point where the reliquefaction line 330, which will be described later, is branched, and can pressurize the evaporative gas. However, if necessary, the compression unit 321 can be provided after the point where the reliquefaction line 330 is branched.

The compression unit 321 can include a compressor 321a that compresses the evaporative gas and a cooler 321b that cools the evaporative gas whose temperature has risen during the compression process.

At this time, the compression unit 321 may be provided at multiple ends. That is, a cooler 321b provided between the multi-stage compressor 321a and each compressor 321a can be included. On the other hand, some coolers 321b may be omitted, including those in which the cooler 321b is provided after the last compressor 321a.

In FIG. 3, the compressor 321 is shown to consist of a three-stage compressor 321a and a cooler 321b, but this is only an example, and the pressure conditions and / or temperatures required by the evaporative gas consuming means 11 and 12 are only examples. The configuration of the compressor 321a and / or the cooler 321b constituting the compression unit 321 can be changed accordingly.

On the other hand, as described above, the fuel conditions required by the first consuming means 11 to the second consuming means 12 may differ from each other. As an example, the first consumption means 11 can use natural gas in a high pressure state as a raw material, and the second consumption means 12 can use natural gas in a low pressure state as a raw material. At this time, the compression unit 321 provided in multiple stages can pressurize and cool the evaporative gas to adjust the pressure and temperature to the pressure and temperature states required by the consumption means 11 and 12.

Further, a heat exchange section 332 of the reliquefaction line 330, which will be described later, may be installed in front of the compression section 321 on the evaporative gas supply line 320, and a detailed description thereof will be described later.

The evaporative gas supply line 320 can include a high-pressure evaporative gas supply line 322 and a low-pressure evaporative gas supply line 323. The high-pressure evaporative gas supply line 322 is connected to the subsequent stage of the compression unit 321 and is connected to the first consumption means 11. Since the evaporative gas provided to the first consuming means 11 through the high-pressure evaporative gas supply line 322 is in a state of being compressed to a high pressure while passing through the compression unit 321 provided with the multi-stage compressor 321a, the high-pressure natural gas is used as a raw material. It is possible to provide the evaporative gas in the state required by the first consuming means 11 to be used.

Then, the low-pressure evaporative gas supply line 323 is branched in the middle of the compression unit 321 and connected to the second consumption means 12. Since the evaporative gas provided to the second consuming means 12 through the low-pressure evaporative gas supply line 323 has passed only a part of the compressor 321a, it can be branched in the low-pressure state required by the second consuming means 12.

On the other hand, the point at which the low-pressure evaporative gas supply line 323 is branched may be provided different from the drawing. That is, the low-pressure evaporative gas supply line 323 may be branched at one point in the middle of the compression unit 321 provided in multiple stages depending on the evaporative gas pressure and temperature conditions required by the second consuming means 12.

On the other hand, the high-pressure evaporative gas supply line 322 may include a first on-off valve 322a, and the low-pressure evaporative gas supply line 323 may include a second on-off valve 323a. The opening / closing of the high-pressure evaporative gas supply line 322 can be adjusted so that the first opening / closing valve 322a is opened when the first consuming means 11 is operated. Then, the opening / closing of the low-pressure evaporative gas supply line 323 can be adjusted so that the second opening / closing valve 323a is opened when the second consumption means 12 is operated.

The reliquefaction line 330 includes a reliquefaction expansion unit 331 that expands the high-pressure evaporative gas branched by the evaporative gas supply line 320, a heat exchange unit 332 that heat-exchanges and cools the evaporative gas that has passed through the re-liquefaction expansion unit 331, and heat exchange. A gas-liquid separator 334 that passes through the unit 332 and stores the reliquefied evaporative gas, a liquefied gas recovery line 335 that resupplyes the evaporative gas of the liquid component separated by the gas-liquid separator 334 to the storage tank 310, and the gas. The evaporative gas circulation line 336 that supplies the evaporative gas of the gas component separated by the liquid separator 334 to the storage tank 310 or the evaporative gas supply line 320 can be provided.

The reliquefaction line 330 can reliquefy the excess evaporative gas remaining unconsumed by the first consuming means 11 and the second consuming means 12 and then return it to the storage tank 310. That is, the evaporative gas can be returned to the storage tank 310 after being decompressed and cooled while passing through the reliquefaction line 330 and undergoing a phase change to the liquefied gas.

The reliquefaction line 330 may be branched from the evaporative gas supply line 320. As an example, it may be branched between the rear stage of the compression unit 321 and the first opening / closing valve 322a.

A three-way valve (not shown) may be provided at the point where the reliquefaction line 330 and the evaporative gas supply line 320 are branched, and the three-way valve is for the evaporative gas supplied to the first consumption means 11 or the reliquefaction line 330. The supply amount can be adjusted. The three-way valve may be manually opened / closed by the operator and the degree of opening / closing may be adjusted, or its operation may be automatically realized by a control unit (not shown).

On the other hand, unlike the drawing, the reliquefaction line 330 may be branched from the middle of the compression unit 321. Alternatively, the reliquefaction line 330 may include all the first reliquefaction line (not shown) branched from the subsequent stage of the compression unit 321 and the second reliquefaction line (not shown) branched from the middle of the compression unit 321. it can. On the other hand, the first reliquefaction line and the second reliquefaction line can flow into the storage tank 310 or merge in one flow path and then flow into the storage tank 310, respectively. In the latter case, since the pressures of the evaporative gas passing through the first reliquefaction line and the second reliquefaction line are different from each other, the pressure of the evaporative gas passing through the respective reliquefaction lines is adjusted to be the same before the two reliquefaction lines merge. Further possible pressure regulating means (not shown) may be provided.

The reliquefaction expansion unit 331 can reduce the pressure by expanding the evaporative gas compressed to a high pressure by the compression unit 321. Although the expansion valve is shown as an example of the reliquefaction expansion unit 331 in the drawing, the reliquefaction expansion unit 331 can be provided by various devices capable of reducing the pressure of the evaporated gas.

The heat exchange unit 332 may be provided so as to exchange heat between the evaporated gas decompressed through the reliquefaction expansion unit 331 and the evaporative gas in the previous stage of the compression unit 321 passing through the evaporative gas supply line 320. The evaporative gas that has passed through the reliquefaction expansion unit 331 is pressurized while passing through the compression unit 321 and the temperature rises. Therefore, heat is exchanged with the low-temperature evaporative gas before passing through the compression unit 321 of the evaporation gas supply line 320. By doing so, the evaporative gas passing through the reliquefaction line 330 can be cooled.

In this way, the evaporative gas that has passed through the reliquefaction expansion unit 331 and is decompressed can be cooled by exchanging heat with the evaporative gas that passes through the evaporative gas supply line 320 without a separate cooling device. Waste can be prevented and equipment operation efficiency can be improved.

On the other hand, the heat exchange unit 332 uses a separate cooling device to exchange the evaporative gas passing through the reliquefaction line 330 with the evaporative gas of the evaporative gas supply line 320 instead of exchanging heat with the evaporative gas passing through the reliquefaction line 330. It can also be cooled. As an example, a cooling device utilizing liquefied nitrogen can be used to cool the evaporative gas passing through the reliquefaction line 330.

On the other hand, the heat exchange unit 332 can further utilize a separate cooling device in addition to exchanging heat with the evaporative gas of the evaporative gas supply line 320 in order to cool the evaporative gas passing through the reliquefaction line 330.

The evaporative gas flowing along the reliquefaction line 330 can pass through the reliquefaction expansion unit 331 and the heat exchange unit 332 and be reliquefied. At this time, the reliquefaction of the evaporative gas includes one in which the entire amount is reliquefied and one in which only a part is reliquefied.

The evaporative gas is reliquefied while the temperature drops, and the reliquefied evaporative gas partially vaporizes during the depressurization process. In order to inject into the storage tank 310, the evaporative gas should be depressurized, but when the evaporative gas is liquefied and then depressurized, the amount of the liquefied evaporative gas vaporized may increase. Therefore, it is preferable to carry out all depressurization and cooling according to appropriate temperature and pressure conditions.

Since the evaporative gas flowing along the reliquefaction line 330 is depressurized while passing through the reliquefaction expansion section 331 and at the same time cooled while passing through the heat exchange section 332, reliquefaction occurs.

The gas-liquid separator 334 accommodates the partially reliquefied evaporative gas while passing through the reliquefaction expansion unit 331 and the heat exchange unit 332, and separates the liquid component and the gas component of the reliquefied evaporative gas. The pressurized evaporative gas is depressurized and cooled to reliquefy a large amount of evaporative gas, or a flash gas (Flash Gas) is generated in this process to generate a gas component of the reliquefied evaporative gas. Because there is a possibility.

The liquid component of the reliquefied evaporative gas separated by the gas-liquid separator 334 is resupplied to the storage tank 310 by the liquefied gas recovery line 335 described later, and the gas component of the separated reliquefied evaporative gas is described later. It may be provided to be resupplied to the storage tank 310 or the evaporative gas supply line 320 by the evaporative gas circulation line 336.

The liquefied gas recovery line 335 can connect the gas-liquid separator 334 and the storage tank 310 so as to resupply the liquid component of the evaporative gas separated by the gas-liquid separator 334 to the storage tank 310. The liquefied gas recovery line 335 may be provided with its inlet-side end connected to the lower side of the gas-liquid separator 334 and its outlet-side end connected to the inside of the storage tank 310. The liquefied gas recovery line 335 may be provided with an on-off valve (not shown) for adjusting the supply amount of the reliquefied evaporative gas recovered in the storage tank 310.

The evaporative gas circulation line 336 resupplys the gas component of the reliquefied evaporative gas separated by the gas-liquid separator 334 to the storage tank 310 or the evaporative gas supply line 320, so that the gas-liquid separator 334 and the storage tank 310 Alternatively, it may be provided so as to connect the gas-liquid separator 334 and the evaporative gas supply line 320. In the drawing, the evaporative gas circulation line 336 is shown in which the gas component inside the gas-liquid separator 334 is resupplied to the front stage of the compression unit 321 on the evaporative gas supply line 320, but in addition to this, the evaporative gas circulation line 336 Includes the case where the gas component inside the gas-liquid separator 334 is re-supplied from the gas-liquid separator 334 to the storage tank 310, or both the evaporative gas supply line 320 and the storage tank 310 are re-supplied.

The liquefied gas supply line 340 may be provided to supply the liquefied natural gas contained or stored in the storage tank 310 to an engine, a generator, and / or a turbine or the like.

The drawings show that the liquefied gas supply line 340 supplies liquefied natural gas to the evaporative gas consuming means 11 and 12. However, this is only an example, and the liquefied gas supply line 340 may be provided so as to supply the liquefied natural gas to a device separate from the evaporative gas consuming means 11 and 12.

Hereinafter, the liquefied gas supply line 340 will be described as an example in which the liquefied gas supply line 340 is connected to the first consumption means 11 and the second consumption means 12, respectively. At this time, the first consumption means 11 and the second consumption means 12 will be described by taking an engine as an example.

One end of the liquefied gas supply line 340 may be connected to the inside of the storage tank 310, and the other end may be provided so as to merge with the evaporative gas supply line 320 described later and be connected to the engines 11 and 12. The inlet side end of the liquefied gas supply line 340 may be located below the interior of the storage tank 310 and may be provided with a delivery pump 341 for supplying the liquefied natural gas to the engines 11 and 12.

As described above, the engines 11 and 12 are composed of a first engine 11 that receives a relatively high pressure fuel gas and generates an output, and a second engine 12 that receives a relatively low pressure fuel gas and generates an output. In some cases, the liquefied gas supply line 340 includes a second liquefied gas supply line 340b and a first liquefied gas supply line 340a so that the liquefied natural gas can be processed according to the fuel gas requirements of the engines 11 and 12, respectively. Can be provided in.

The first liquefied gas supply line 340a can supply the liquefied natural gas delivered by the delivery pump 341 to the first engine 11 that receives a relatively high pressure fuel gas and generates an output. For this purpose, the first liquefied gas supply line 340a may be provided with a pressurizing pump 342 for compressing the liquefied natural gas. The pressurizing pump 342 can compress the liquefied natural gas according to the pressure condition of the fuel gas required by the first engine 11, and as an example, when the first engine 11 is composed of a ME-GI engine, the pressurizing pump 342 is used. 342 can supply liquefied natural gas by compressing it under a pressure condition of about 250-300 bar. The liquefied natural gas compressed by the pressurizing pump 342 can be forcibly vaporized while passing through the vaporizer 343 and then merged with the evaporative gas supply line 320 and supplied to the first engine 11 as fuel gas.

On the other hand, when maintenance of the pressurizing pump 342 is required or a load is applied to the pressurizing pump 342 and the power supply must be shut off, if the power supply of the pressurizing pump 342 is temporarily shut off, compressed liquefied natural gas is used. May affect the pressurizing pump 342 or other configurations, resulting in failure of the pressurizing pump 342 or a safety accident. In addition, maintenance of the pressurizing pump 342 should be required, or a load should be applied to the pressurizing pump 342 to shut off the power supply, but continuous operation of the engine may be required.

For this purpose, a bypass line 340c may be provided in the first liquefied gas supply line 340a. The inlet side end of the bypass line 340c is connected to the front stage of the pressurizing pump 342 on the first liquefied gas supply line 340a, and the outlet side end is connected to the rear stage of the pressurizing pump 342 on the first liquefied gas supply line 340a. However, a separate pressurizing pump 342 may be additionally provided so that the pressurizing pumps 342 are connected in parallel.

Since a plurality of pressurizing pumps 342 are provided in parallel on the first liquefied gas supply line 340a by a bypass line 340c provided with a separate pressurizing pump 342, the pressurizing pump 342 and other configurations fail even in the above-mentioned situation. It is possible to prevent the occurrence of safety accidents and to realize long-term continuous operation of the engine.

The second liquefied gas supply line 340b can supply the liquefied natural gas delivered by the delivery pump 341 to the second engine 12 that receives a relatively low pressure fuel gas and generates an output. Since the liquefied natural gas is compressed at a low pressure (about 3 bar to 5 bar) in the process of the delivery pump 341 delivering the liquefied natural gas, if the second engine 12 is composed of a DFDE engine, it is vaporized without a separate pressurizing pump. The vessel 344 can forcibly vaporize the liquefied natural gas delivered by the delivery pump 341 to supply the fuel gas in accordance with the fuel conditions required by the second engine 12.

A gas-liquid separator 345 may be provided after the vaporizer 344. When the second engine 12 is composed of a DFDE engine, normal output cannot be generated unless the fuel gas is supplied in a gaseous state, and engine failure cannot be prevented. Therefore, the liquefied natural gas that has passed through the vaporizer 344 is supplied to the gas-liquid separator 345, and only the gaseous fuel gas is supplied to the second engine 12 by the gas-liquid separator 345. The reliability of the gas can be improved.

Hereinafter, the ship's evaporative gas treatment device 400 according to the fourth embodiment of the present invention will be described. In the description of the ship's evaporative gas treatment device 400 according to the fourth embodiment of the present invention described below, in addition to the configuration additionally described with a separate drawing number, the ship according to the third embodiment described above The description is the same as that for the evaporative gas processing apparatus 300, and the description is omitted in order to prevent duplication of contents.

FIG. 4 is a conceptual diagram showing the ship's evaporative gas treatment device 400 according to the fourth embodiment of the present invention. With reference to FIG. 4, the ship's evaporative gas treatment device 400 according to the fourth embodiment of the present invention is reconstructed. An expansion valve 433, which is provided on the liquefaction line 330 and depressurizes the evaporative gas that has passed through the heat exchange unit 332, can be further included.

The expansion valve 433 may be provided after the heat exchange unit 332. The expansion valve 433 can be additionally cooled and expanded by reducing the pressure of the evaporative gas that has passed through the reliquefaction expansion unit 331 and the heat exchange unit 332 to improve the reliquefaction efficiency. As an example, the expansion valve 433 can use a Joule-Thomson valve. A Joule-Thomson valve means a valve that utilizes the Joule-Thomson effect, that is, the phenomenon in which the temperature drops when a fluid is expanded in the absence of work production or heat transfer. Therefore, the evaporative gas cooled while passing through the heat exchange unit 332 is adiabatically expanded and cooled while passing through the expansion valve 433, and at this time, reliquefaction of the evaporative gas in whole or in part may occur.

Hereinafter, the efficiency of the evaporative gas treatment devices 300 and 400 for ships according to the third and fourth embodiments of the present invention will be described with reference to FIGS. 5 to 10.

FIG. 5 is required for the mass flow rate (Mc: Mass flow to Compressor) and the compression unit 321 of the evaporative gas entering the compression unit 321 due to the pressure of the evaporative gas entering the heat exchange unit 332 (Pb: Pressure before BOG). It is a graph which shows the correlation of energy (Ec: Energy for Compressor).

Referring to FIG. 5, the mass flow rate (Mc) of the evaporative gas entering the compression unit 321 and the energy (Ec) required by the compression unit 321 are determined by the pressure (Pb) of the evaporative gas entering the heat exchange unit 332. change. At this time, when the pressure (Pb) of the evaporative gas entering the heat exchange unit 332 is the optimum pressure (Pb1), the mass flow rate (Mc) of the evaporative gas entering the compression unit 321 and the energy required by the compression unit 321. (Ec) is the minimum. That is, when the pressure (Pb) of the evaporative gas entering the heat exchange unit 332 is smaller than the optimum pressure (Pb1), the mass flow rate (Mc) of the evaporative gas entering the compression unit 321 and the energy required by the compression unit (Mc). When the Ec) becomes large and the pressure (Pb) of the evaporative gas entering the heat exchange unit 332 is larger than the optimum pressure (Pb1), the mass flow rate (Mc) of the evaporative gas entering the compression unit 321 and the compression unit 321 are required. The energy (Ec) that is said to be increased.

Therefore, by adjusting the pressure (Pb) of the evaporative gas entering the heat exchange unit 332 to the optimum pressure (Pb1) and reducing the mass flow rate (Mc) of the evaporative gas entering the compression unit 321, the compressor 321a and the compressor 321a The size of the cooler 321b can be reduced, and the equipment unit price can be reduced. Therefore, a more compact and economical ship evaporative gas treatment device can be manufactured.

Further, by adjusting the pressure (Pb) of the evaporative gas entering the heat exchange unit 332 to the optimum pressure (Pb1) and lowering the energy (Ec) required by the compression unit 321, the evaporative gas treatment device of the ship Efficiency can be improved. That is, it is possible to reduce the energy used for compressing the evaporative gas while maintaining the same pressure in the subsequent stage of the compression unit 321.

Next, the effect of reducing the pressure (Pb) of the evaporative gas entering the heat exchange unit 332 will be described with reference to FIGS. 6 to 8.

FIG. 6 shows the mass flow rate (Mr: Mass flow of Re-Liquified BOG) of the evaporative gas reliquefied by the mass flow rate (Mf: Mass flow of Full Connection) of the evaporative gas required by the evaporative gas consuming means 11 and 12. It is a graph which shows the correlation of.

With reference to FIG. 6, the mass flow rate (Mr) of the evaporative gas reliquefied changes depending on the mass flow rate (Mf) of the evaporative gas required by the consumption means 11 and 12. At this time, the mass flow rate (Mf) of the evaporative gas required by the consuming means 11 and 12 and the mass flow rate (Mr) of the evaporative gas to be reliquefied are in an inverse proportional relationship. That is, as the mass flow rate (Mf) of the evaporative gas required by the consuming means 11 and 12 increases, the mass flow rate (Mr) of the evaporative gas reliquefied decreases.

On the other hand, the pressure (Pb) of the evaporative gas entering the heat exchange section 332 is reduced while passing through the reliquefaction expansion section 331. When is Pb2, the relationship of Pb1> Pb2 is established.

With reference to FIG. 6 again, it can be seen that the mass flow rate (Mr) of the evaporative gas reliquefied in the reliquefaction expansion unit 331 is constant regardless of the decompression of the evaporative gas. That is, lowering the pressure (Pb) of the evaporative gas entering the heat exchange unit 332 through the reliquefaction expansion unit 331 does not reduce the reliquefaction rate.

FIG. 7 is a graph showing the correlation between the mass flow rate (Mf) of the evaporative gas required by the evaporative gas consuming means 11 and 12 and the mass flow rate (Mc) of the evaporative gas entering the compression unit 321.

Referring to FIG. 7, the mass flow rate (Mc) of the evaporative gas entering the compression unit 321 changes depending on the mass flow rate (Mf) of the evaporative gas required by the consumption means 11 and 12. At this time, the mass flow rate (Mf) of the evaporative gas required by the consuming means 11 and 12 and the mass flow rate (Mc) of the evaporative gas entering the compression unit 321 are inversely proportional to each other. That is, as the mass flow rate (Mf) of the evaporative gas required by the consuming means 11 and 12 increases, the mass flow rate (Mc) of the evaporative gas entering the compression unit 321 decreases.

With reference to FIG. 7 again, it can be seen that the mass flow rate (Mc) of the evaporative gas entering the compression unit 321 decreases while the pressure (Pb) of the evaporative gas entering the heat exchange unit 332 is reduced from P1 to P2. .. That is, the pressure (Pb) of the evaporative gas is reduced by using the reliquefaction expansion unit 331 to reduce the mass flow rate (Mc) of the evaporative gas entering the compressor 321 so that the compressor 321a and the cooler 321b The size can be reduced and the equipment unit price can be reduced. Therefore, a more compact and economical ship evaporative gas treatment device can be manufactured.

FIG. 8 is a graph showing the correlation of the energy (Ec) required by the compression unit 321 with the mass flow rate (Mf) of the evaporative gas required by the evaporative gas consuming means 11 and 12.

Referring to FIG. 8, the energy (Ec) required by the compression unit 321 changes depending on the mass flow rate (Mf) of the evaporative gas required by the consumption means 11 and 12. At this time, the mass flow rate (Mf) of the evaporative gas required by the consuming means 11 and 12 and the energy (Ec) required by the compression unit 321 are inversely proportional to each other. That is, as the mass flow rate (Mf) of the evaporative gas required by the consumption means 11 and 12 increases, the energy (Ec) required by the compression unit 321 decreases.

With reference to FIG. 8 again, it can be seen that the energy (Ec) required by the compression unit 321 decreases while the pressure (Pb) of the evaporative gas entering the heat exchange unit 332 is reduced from P1 to P2. That is, the efficiency of the evaporative gas treatment device of the ship is improved by reducing the pressure (Pb) of the evaporative gas by using the reliquefaction expansion unit 331 to lower the energy (Ec) required by the compression unit 321. Can be made to. That is, the energy used for compressing the evaporative gas can be reduced while maintaining the same pressure in the subsequent stage of the compression unit 321.

9 and 10 are graphs showing the correlation between the mass flow rate (Mg: Mass flow of Flash Gas) of the flash gas due to the pressure (Pb) of the evaporative gas entering the heat exchange unit 332. The graph of FIG. 9 shows the case where the content of the nitrogen component contained in the evaporative gas is amole%, and the graph of FIG. 10 shows the case where the content of the nitrogen component contained in the evaporative gas is bmore%. At this time, the relationship of a <b is established.

When the mass flow rate (Mg) of the flash gas decreases, the mass flow rate (Mc) of the evaporative gas entering the compression unit 321 decreases. Therefore, the size of the compression unit 321 can be reduced, and the energy (Ec) required by the compression unit 321 can be reduced.

The mass flow rate (Mg) of the flash gas changes depending on the pressure (Pb) of the evaporative gas entering the heat exchange unit 332. At this time, the mass flow rate (Mg) of the flash gas generated when the pressure (Pb) of the evaporative gas entering the heat exchange unit 332 is the optimum pressure (Pb1) is minimized. That is, when the pressure (Pb) of the evaporative gas entering the heat exchange unit 332 is smaller than the optimum pressure (Pb1), the mass flow rate (Mg) of the flash gas generated increases, and the evaporative gas entering the heat exchange unit 332 increases. The mass flow rate (Mg) of the flash gas generated also increases when the pressure (Pb) is larger than the optimum pressure (Pb1).

Therefore, the mass flow rate (Mg) of the flash gas generated by adjusting the pressure (Pb) of the evaporative gas entering the heat exchange unit 332 to the optimum pressure (Pb1) can be reduced.

The amount of flash gas generated is related not only to pressure but also to temperature. That is, the pressure drops and the liquefied gas vaporizes to form a flash gas, and the temperature rises and the liquefied gas vaporizes to form a flash gas.

If the pressure (Pb) of the evaporative gas entering the heat exchange unit 332 becomes smaller than the optimum pressure (Pb1), the amount of flash gas generated due to decompression decreases, but on the contrary, the temperature drops in the heat exchange unit 332. Will decrease, and the overall amount of flash gas generated will increase. This is because the temperature drop of the heat exchange unit 332 occurs at the same time as the depressurization process, so that when the decompression degree is small, the temperature drop degree also decreases.

On the contrary, when the pressure (Pb) of the evaporative gas entering the heat exchange unit 332 becomes higher than the optimum pressure (Pb1), the decompression degree is sufficient, so that the temperature drops considerably, or rather the flash gas generated in the decompression process. Increases and the overall amount of flash gas generated increases.

On the other hand, when FIG. 9 and FIG. 10 are compared, it can be seen that as the content of the nitrogen component changes, the optimum pressure (Pb1) that minimizes the mass flow rate (Mg) of the flash gas changes. That is, as the content of the nitrogen component increases (a <b), the optimum pressure (Pb1) also increases.

The content of the nitrogen component of the evaporative gas is related to the amount of liquefied natural gas stored in the storage tank 310. In the case of a full-ship voyage in which the amount of liquefied natural gas stored in the storage tank 310 is large, the content of the nitrogen component is large.

However, as time elapses, evaporative gas is continuously generated and the consumption of evaporative gas or liquefied natural gas consumed by the evaporative gas consuming means 11 and 12 also increases, and the liquefied natural gas stored in the storage tank 310 increases. Storage will be reduced. In the case of such an airship voyage, the content of the nitrogen component becomes small.

On the other hand, the content of the nitrogen component decreases sharply at the initial stage when the evaporative gas is generated, but decreases with a gentle slope after the evaporative gas is generated to some extent. The content of the nitrogen component is generally between 0 mole% and 10 mole%. The pressure (about 300 bar) in the pre-stage of the reliquefaction expansion portion 331 is adjusted to a value between a minimum of 50 bar and a maximum of 160 bar by the content of such a nitrogen component.

As an example, when the content of the nitrogen component is 10 mole%, the optimum pressure (Pb1) is about 140 bar to 160 bar. Therefore, the pressure (about 300 bar) in the pre-stage of the reliquefaction expansion unit 331 is adjusted to about 150 bar. Further, when the content of the nitrogen component is 0 mole%, the optimum pressure (Pb1) is about 50 bar to 70 bar. Therefore, the pressure (about 300 bar) in the pre-stage of the reliquefaction expansion unit 331 is adjusted to about 60 bar.

As described in detail above, the optimum pressure (Pb1) that can minimize the amount of flash gas generated fluctuates while the amount of liquefied natural gas stored in the storage tank 310 fluctuates. Therefore, it is necessary to adjust the degree of depressurization by the reliquefaction expansion unit 331 so as to match the fluctuating optimum pressure (Pb1).

The ship's evaporative gas treatment devices 300 and 400 according to the third and fourth embodiments of the present invention are installed in the evaporative gas supply line 320 so that the flow rate of the evaporative gas entering the compression unit 321 can be measured. Sensor 351, a sensor 352 installed in the evaporative gas supply line 320 so that the flow rate of the evaporative gas generated in the storage tank 310 and entering the heat exchange unit 332 can be measured, and a gas-liquid separator 334. A sensor 353 installed on the evaporative gas circulation line 336 can be included so that the flow rate of the flash gas generated and merged with the evaporative gas supply line 320 can be measured. The positions of the sensors 351 and 352, 353 can vary from the drawings.

On the other hand, the flow rate of the flash gas can be measured not only by using the sensors 353 installed in the evaporative gas circulation line 336 but also by using the sensors 351 and 352 installed in the evaporative gas supply line 320. When the measured amount of any one of the sensors 351, 352, and 353 increases, it can be determined that the amount of flash gas generated has increased.

The reliquefaction expansion unit 331 may be provided so that the degree of decompression can be adjusted. That is, when the evaporative gas of the same pressure flows in, the pressure of the evaporative gas flowing into the heat exchange unit 332 through the reliquefaction expansion unit 331 can be different. Therefore, the flow rate of the flash gas can be adjusted by adjusting the pressure of the evaporative gas that has passed through the reliquefaction expansion unit 331.

Specifically, if the flow rate of any one of the sensors 351, 352, and 353 increases when the depressurization degree of the reliquefaction expansion unit 331 is increased, the pressure of the evaporative gas entering the heat exchange unit 332 ( It is determined that Pb) has changed in the direction farther from the optimum pressure (Pb1), and the degree of depressurization of the reliquefaction expansion unit 331 is reduced. On the contrary, if the flow rate of any one of the sensors 351, 352, and 353 decreases when the depressurization degree of the reliquefaction expansion unit 331 is increased, the pressure (Pb) of the evaporative gas entering the heat exchange unit 332. Is determined to have changed in the direction approaching the optimum pressure (Pb1), and the depressurization degree of the reliquefaction expansion unit 331 is continuously increased.

Such a control method can be similarly applied even when the degree of depressurization of the reliquefaction expansion unit 331 is reduced.

Unlike this, the ship's evaporative gas treatment devices 300 and 400 according to the third and fourth embodiments of the present invention are the reliquefied evaporative gas resupplied from the gas-liquid separator 334 to the storage tank 310. A sensor 355 installed in the liquefied gas recovery line 335 is further included to measure the supply amount of the gas, and the degree of depressurization of the reliquefaction expansion unit 331 can be adjusted based on the measurement amount of the sensor 355.

Specifically, if the flow rate of the sensor 355 increases when the depressurization degree of the reliquefaction expansion unit 331 is increased, the amount of flash gas generated has decreased, so that the evaporative gas entering the heat exchange unit 332 has decreased. It is determined that the pressure (Pb) has changed in the direction approaching the optimum pressure (Pb1), and the depressurization degree of the reliquefaction expansion unit 3311 is continuously increased. On the contrary, if the flow rate of the sensor 355 decreases when the depressurization degree of the reliquefaction expansion unit 331 is increased, the amount of flash gas generated has increased, and the pressure of the evaporative gas entering the heat exchange unit 332 ( It is determined that Pb) has changed in the direction farther from the optimum pressure (Pb1), and the degree of depressurization of the reliquefaction expansion unit 331 is reduced.

Such a control method can be similarly applied even when the degree of depressurization of the reliquefaction expansion unit 331 is reduced.

In the above examples, as an example for assisting the understanding of the present invention, the relative relationship between liquefied natural gas and liquefied ethane gas and the evaporative gas generated from the relative relationship have been described, but the description is not limited to this, and methane is not limited thereto. The same technical idea can be applied to different types of liquefied gases having relatively different component ratios.

The present invention has been described with reference to an embodiment illustrated in the accompanying drawings, but this is merely exemplary and will vary from those who have ordinary knowledge in the art. It should be understood that other embodiments of modification and equality are possible. Therefore, the true scope of the invention should be defined only by the appended claims.

Claims (6)

Evaporative gas supply line that provides the evaporative gas contained in the storage tank to the evaporative gas consumption means;
A compression unit provided in the evaporative gas supply line to pressurize the evaporative gas;
A reliquefaction line that is branched from the evaporative gas supply line and reliquefies the branched and flowing evaporative gas;
A heat exchange unit that exchanges heat between the reliquefaction line and the evaporative gas supply line; and the evaporative gas provided in the reliquefaction line before entering the heat exchange unit is expanded to reduce the flow rate of the evaporative gas supply line. reliquefaction expansion unit for adjusting the vacuum degree of the evaporator gas in a direction to decrease; only contains,
The reliquefaction expansion unit is provided so as to reduce the pressure of the evaporative gas branched from the evaporative gas supply line to 50 bar to 160 bar.
When the content of the nitrogen component of the evaporative gas in the storage tank is 10 mole%, the reliquefaction expansion unit reduces the evaporative gas branched from the evaporative gas supply line to 140 bar to 160 bar and reduces the pressure in the storage tank to 140 bar to 160 bar. When the content of the nitrogen component of the evaporative gas is 0 mole%, the evaporative gas branched from the evaporative gas supply line is reduced to 50 bar to 70 bar.
Evaporative gas treatment equipment for ships. Claim 1 further includes an expansion valve that reduces the pressure of the evaporative gas that has passed through the heat exchange unit, and a gas-liquid separator that separates the reliquefied evaporative gas that has passed through the expansion valve into a gas component and a liquid component. Evaporative gas treatment device for ships according to. The reliquefaction line is a liquefied gas recovery line that supplies the liquid component separated by the gas-liquid separator to the storage tank and a gas component separated by the gas-liquid separator on the storage tank or the evaporative gas supply line. The ship's evaporative gas treatment apparatus according to claim 2, further comprising an evaporative gas circulation line supplied to the pre-stage of the compression unit. Evaporative gas supply line that provides the evaporative gas contained in the storage tank to the evaporative gas consumption means; a compression unit provided in the evaporative gas supply line to pressurize the evaporative gas; branched from the evaporative gas supply line and branched. A reliquefaction line that reliquefies the flowing evaporative gas; a heat exchange unit that exchanges heat between the reliquefaction line and the evaporative gas supply line; and an evaporative gas provided in the reliquefaction line before entering the heat exchange unit. Evaporation of a ship that treats the evaporative gas using the evaporative gas treatment device of the ship including the reliquefaction expansion part; which adjusts the degree of decompression of the evaporative gas in the direction of reducing the flow rate of the evaporative gas supply line In the gas treatment method
Measure the flow rate of the evaporative gas supply line and
If the flow rate measured by the evaporative gas supply line increases when the degree of decompression of the reliquefaction expansion unit is adjusted in any one direction (increase or decrease direction), the decompression of the reliquefaction expansion unit is reduced. Adjust the degree in the other direction,
If the flow rate measured in the evaporative gas supply line becomes smaller when the degree of decompression of the reliquefaction expansion part is adjusted in any one direction (increase direction or decrease direction), the decompression of the reliquefaction expansion part is reduced. A method for treating evaporative gas on a ship, in which the degree is continuously adjusted in the above-mentioned one direction. The method for treating evaporative gas on a ship according to claim 4 , wherein the pressure of the evaporative gas decompressed through the reliquefaction expansion unit is adjusted to a target pressure that minimizes the flow rate measured in the evaporative gas supply line. As the amount of liquefied gas stored in the storage tank changes, the target pressure of the evaporated gas decompressed through the reliquefaction expansion unit changes.
The method for treating evaporative gas on a ship according to claim 5 , wherein the degree of decompression of the reliquefaction expansion portion is adjusted to the changed target pressure.

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