JP2021021395A - Fuel supply system and fuel supply method in crude oil carrying vessel - Google Patents

Abstract

To provide a fuel supply system that allows a volatile organic compound generated in a crude oil storage tank of a crude oil carrying vessel that uses liquefied natural gas as fuel to be used as fuel for an engine.SOLUTION: A fuel supply system of a crude oil carrying vessel includes: a VOC collection tank for collecting VOC in a gaseous state discharged from a crude oil storage tank without causing a phase change; a fuel storage tank for storing LNG used as fuel for an engine; a fuel pump for pressurizing the LNG stored in the fuel storage tank and discharging it; and a mixer for mixing the LNG in a liquid state pressurized by the fuel pump and the VOC in a gaseous state discharged from the VOC collection tank. The fuel supply system further includes a mixed fuel supply line for connecting the mixer and the engine, which is a two-stroke cycle diesel engine, and supplying mixed fuel, which is mixed by the mixer, to the engine, and a VOC supply line for connecting the VOC collection tank and the mixer, and transferring the VOC containing nitrogen and a heavy hydrocarbon component from the VOC collection tank to the mixer.SELECTED DRAWING: Figure 2

Description

The present invention relates to a fuel supply system and a fuel supply method capable of using a volatile organic compound generated in a crude oil storage tank of a crude oil carrier using liquefied natural gas as a fuel as a fuel for an engine.

Crude oil carriers are equipped with a large number of cargo tanks for storing crude oil. In the crude oil storage tank, the stored crude oil evaporates to generate volatile organic compounds (VOCs) (see, for example, Patent Documents 1 and 2). In order to maintain the pressure in the crude oil storage tank safely, the VOC generated in the crude oil storage tank must be discharged to the outside.

In particular, during the process of loading crude oil into the crude oil storage tank, during full-ship operation (laden voyage), and after discharging the crude oil to the customer, the crude oil storage tank is cleaned. At that time, a considerable amount of VOC is generated.

The composition of VOCs contains almost all components of crude oil stored in crude oil storage tanks, i.e. organic compounds. When VOCs are released into the atmosphere, they undergo a photochemical reaction with nitrogen oxides under the action of sunlight, generate ozone and photochemical oxidizing substances, induce photochemical smog, destroy the ozone layer, and have a greenhouse effect. It will cause environmental pollution such as affecting.

Due to the harmfulness of these VOCs, the International Maritime Organization and others regulate VOC cargo handling at some ports. Not only that, the release of VOCs into the atmosphere means that the active substances are lost in the end, so it is necessary to take a method of recovering VOCs and treating them efficiently instead of releasing VOCs into the atmosphere. ..

Republic of Korea Patent Application Publication No. 10-2020-0056824 Republic of Korea Patent Application Publication No. 10-2015-0057229

The technologies for efficiently processing VOCs are generally VOC reduction technology that reduces the amount of VOCs generated when loading cargo, and VOC reduction technology that collects and processes the generated VOCs without releasing them into the atmosphere. VOC recovery technology is actually being applied.

VOC generation reduction technology is typically a technology that reduces the generation of negative pressure in the crude oil storage tank when loading cargo into the crude oil storage tank and adjusts the tank pressure below the vapor pressure of the crude oil. ..

The VOC recovery technology is a technology for collecting generated VOCs, liquefying them, storing them, or supplying them as fuel, and uses expensive VOC processing system equipment composed of packages mounted on a ship.

On the other hand, VOCs generated by crude oil carriers have a high content of heavy hydrocarbons and do not satisfy the methane value of gas engines. Therefore, VOCs are reformed into methane, which is a hard hydrocarbon, and supplied using a reformer. There must be.

However, the supply of fuel using the reformer requires repair management to maintain the performance of the reformer on a regular basis, and a large amount of thermal energy such as steam is required for reforming. Therefore, there is a problem that additional fuel combustion is indispensable.

The present invention uses LNG as fuel, but more easily and inexpensively supplies VOC generated from the ship as fuel for the engine without releasing it to the atmosphere. Therefore, the fuel for an improved crude oil carrier is improved. A supply system and a fuel supply method are provided.

In order to achieve the above-mentioned object, according to one embodiment of the present invention, a VOC collection tank that collects VOCs (Volatile Organic Compounds) in a gaseous state discharged from a crude oil storage tank as they are without phase change. A fuel storage tank that stores LNG (Liquefied Natural Gas) used as engine fuel, a fuel pump that pressurizes and discharges LNG stored in the fuel storage tank, and a liquid state that is pressurized by the fuel pump. A mixer for mixing LNG and VOCs in a gaseous state discharged from the VOC collection tank is provided, and the engine is a two-stroke diesel cycle engine, and the mixer and the engine are connected to each other and the mixing is performed. The VOC collection tank and the mixer are connected to a mixed fuel supply line that supplies the mixed fuel mixed by the machine to the engine, and VOCs containing nitrogen and heavy hydrocarbon components are collected from the VOC collection tank. Provided is a fuel supply system for a crude oil carrier, further comprising a VOC supply line for transfer to the mixer.

In the present invention, a high-pressure pump that compresses the mixed fuel in a liquid state mixed by the mixer to the high pressure required by the engine, and a vaporizer that vaporizes the mixed fuel compressed by the high-pressure pump are further provided. It is preferable that the mixed fuel in a gaseous state vaporized by the vaporizer is supplied as the fuel for the engine via the mixed fuel supply line.

Further, in the present invention, it is preferable to further include a VOC valve installed in the VOC supply line and whose opening degree is controlled according to the nitrogen content of the VOC supplied from the VOC collection tank to the mixer. ..

Further, in the present invention, it is preferable to further include a control unit that controls the opening degree of the VOC valve so that the nitrogen content of the mixed fuel mixed by the mixer is less than 30 mol%.

Further, in the present invention, the engine is preferably a gas engine using 100% ethane gas, 100% natural gas, a mixture of natural gas and VOC, and VOC as fuel.

Further, in the present invention, it is preferable that the high-pressure pump compresses the mixed fuel to 200 bar to 420 bar.

Further, in the present invention, it is preferable that the mixer is an ejector using the liquid state LNG as a working fluid.

Further, in the present invention, a VOC collection line that connects the crude oil storage tank and the VOC collection tank and transfers VOCs containing nitrogen and heavy hydrocarbon components from the crude oil storage tank to the VOC collection tank. The VOC further comprises, from the crude oil storage tank to the VOC collection tank, and without a pretreatment to remove water and nitrogen (ie, without a pretreatment step to remove water and nitrogen). It is preferable that they are transferred from the VOC collection tank to the mixer, respectively.

In order to achieve the above-mentioned object, according to another embodiment of the present invention, VOCs (Volatile Organic Compounds) in a gaseous state containing nitrogen and heavy hydrocarbon components discharged from a crude oil storage tank are phase-changed. A step of collecting and storing LNG in a gaseous state without using it, a step of compressing LNG used as fuel for an engine, and a mixing step of discharging the stored VOC and mixing it with the compressed liquid state LNG. A method for supplying fuel to a crude oil carrier is provided, which comprises a supply step of supplying a mixed fuel in which LNG and VOC are mixed to a two-stroke diesel cycle engine.

In the present invention, it is preferable that the LNG is used as a working fluid and the VOC in a gaseous state is sucked (sucked) and mixed in the mixing step.

Further, in the present invention, the supply step includes a step of further compressing the mixed fuel to a high pressure required by the engine and a step of vaporizing the mixed fuel compressed to the high pressure, and the vaporized gas. It is preferable to supply the mixed fuel in the state to the engine.

Further, in the present invention, the mixing step preferably includes a step of adjusting the flow rate of VOC in a gaseous state to be mixed with the compressed LNG so that the nitrogen content of the mixed fuel is less than 30 mol%.

According to the fuel supply system and the fuel supply method of the crude oil carrier of the present invention, the process of recovering and utilizing VOCs can be simplified.

In addition, by simplifying the process of collecting and utilizing VOCs, it is possible to maximize the degree of utilization of VOCs generated in the process of cargo handling and operation of crude oil.

In particular, since a device for liquefying the VOC and a pretreatment device for removing water and nitrogen from the VOC are not required, the installation cost, area, and energy cost can be reduced by omitting the additional device.

In addition, VOCs can be recovered without using electric power, and the amount of electric power used by the ship can be reduced.

By supplying the recovered VOCs as fuel for the engine, harmful VOCs can be treated in an environmentally friendly manner without being released into the atmosphere.

It is a block diagram which illustrated the fuel supply system of the crude oil carrier which concerns on 1st Embodiment of this invention simply. It is a block diagram which illustrated the fuel supply system of the crude oil carrier which concerns on 2nd Embodiment of this invention simply. It is a block diagram which illustrated the fuel supply system of the crude oil carrier which concerns on 3rd Embodiment of this invention simply.

In order to fully understand the operational advantages of the present invention and the objectives achieved by the embodiments of the present invention, the description will be made with reference to the accompanying drawings and the contents described in the accompanying drawings illustrating the preferred embodiments of the present invention.

Hereinafter, the configuration and operation of a preferred embodiment of the present invention will be described in detail with reference to the attached drawings. By adding reference numerals for the components of each drawing, the same components are represented by the same code as much as possible, even if they are displayed on other drawings. Further, the following embodiments can be changed to various other embodiments, and the scope of the present invention is not limited to the following embodiments.

In one embodiment of the present invention described later, the liquefied gas is a liquefied gas containing methane and / or ethane, for example, LNG (Liquefied Natural Gas), LEG (Liquefied Ethane Gas), LPG (Liquefied Petroleum Gas), and liquefied. It can be Liquefied Ethylene Gas.

However, in the embodiment described later, a case where it is applied to LNG, which is a typical liquefied gas, will be described as an example. LNG contains methane as a main component and contains ethane, propane, butane, etc., and its composition varies depending on the production area.

Further, the fuel supply system and the fuel supply method of the crude oil carrier according to the embodiment of the present invention, which will be described later, will be described by taking the case of being applied to a ship as an example, but can also be applied to a land-based one.

Further, the ship of the embodiment described later will be described by taking as an example a crude oil carrier or a crude oil tanker that transports the produced crude oil as cargo, but the present invention is a floating body that produces crude oil at sea. Floating Production Storage and Offloading Unit (FPSO), product carrier (Floating Production Storage and Offloading Unit) for transporting produced crude oil, and floating and storage (FSU) for storing produced crude oil. It can be applied to all ships or floating structures on the sea that are equipped with crude oil storage tanks such as Unit), generate a considerable amount of VOC and have potential environmental hazards and need to fuel the engine. ..

Further, the ship according to the embodiment of the present invention, which will be described later, may be an LFS (LNG Fuelled Ship) using LNG as fuel.

Further, in one embodiment of the present invention described later, the liquefied gas and the evaporated gas of the liquefied gas can be used as fuel for an engine, particularly a ship engine.

First, the fuel supply system and the fuel supply method of the crude oil carrier according to the first embodiment of the present invention will be described with reference to FIG.

The fuel supply system for a crude oil carrier according to the first embodiment of the present invention is generated by evaporating crude oil from one or more crude oil storage tanks (cargo tank, 100) for storing crude oil and the crude oil storage tank (100). A VOC collection tank (200) that collects the volatile organic compounds (VOCs) as they are without phase change, and liquefied natural gas (LNG) used as fuel for the ship's engine (1000). Transferred by a fuel storage tank (300) to store, a fuel pump (400) that pressurizes LNG stored in the fuel storage tank (300) and discharges it to the outside from the fuel storage tank (300), and a fuel pump (400). A high-pressure pump (501) that compresses the LNG produced to the pressure range required by the engine (1000), a vaporizer (601) that vaporizes the LNG compressed by the high-pressure pump (501) into natural gas, and a vaporizer. Using the high-pressure natural gas vaporized by (601) as the driving fluid, the low-pressure VOC transferred from the VOC collection tank (200) is sucked in to mix the natural gas and VOC, and the engine (1000) The natural gas, VOC collection tank (200), which is obtained by vaporizing LNG stored in the fuel storage tank (300) and the mixer (701) supplied as fuel for the natural gas using the vaporizer (601). It includes an engine (1000) that uses a mixed fuel of natural gas and VOC mixed by the VOC or the mixer (701) as fuel.

The VOC collection line (VL1) connects the crude oil storage tank (100) and the VOC collection tank (200), and the VOC discharged from the crude oil storage tank (100) passes through the VOC collection line (VL1). Transferred to VOC collection tank (200).

The gaseous VOC discharged from the crude oil storage tank (100) is transferred in the gaseous state via the VOC collection line (VL1) and stored in the VOC collection tank (200) in the gaseous state.

That is, in the present embodiment, the VOC stored in the VOC collection tank (200) is transferred to the VOC collection tank (200) while being transferred from the crude oil storage tank (100) to the VOC collection tank (200). No phase change occurs during storage and during transfer from the VOC collection tank (200) to the mixer (701) via the VOC supply line (VL2).

Further, the VOC collection tank (200) of the present embodiment is provided with a capacity smaller than the capacity of one crude oil storage tank (100).

The VOC discharged from the crude oil storage tank (100) contains not only hydrocarbon components having various carbon atoms but also impurities such as water and nitrogen.

The composition of VOC discharged from the crude oil storage tank (100) varies depending on the composition of crude oil, but generally propane and butane (particularly normal butane) are the main components, and ethane, isobutane, normal pentane and isopentane are also included. , Hexane, heptane, etc. are included.

In addition, it plays a role in carrying out a smooth process when loading crude oil in the crude oil storage tank (100) or discharging crude oil from the crude oil storage tank (100), or blanket gas. Nitrogen gas is supplied to the crude oil storage tank (100) in order to play the role of. Since the liquefaction temperature of nitrogen is lower than the liquefaction temperature of methane, which has the lowest liquefaction temperature among various hydrocarbons contained in VOCs, the VOCs discharged from the crude oil storage tank (100) always contain nitrogen, although their contents are different. It has been.

However, in the fuel supply system according to the present embodiment, a pretreatment device for removing impurities such as water and nitrogen from the VOC transferred from the crude oil storage tank (100) to the VOC collection tank (200) is not installed.

That is, the VOC transferred from the crude oil storage tank (100) to the VOC collection tank (200) does not go through the pretreatment step. Further, the VOC transferred from the VOC collection tank (200) to the mixer (701) does not go through the pretreatment step. VOCs are transferred from the crude oil storage tank (100) to the VOC collection tank (200) and from the VOC collection tank (200) to the mixer (701) without performing the pretreatment for removing water and nitrogen in this way. Be transferred.

The gaseous VOCs collected in the VOC collection tank (200) do not undergo phase change via the VOC supply line (VL2) connecting the VOC collection tank (200) and the mixer (701), and the mixer (VOC) Transferred to 701).

A VOC valve (CV) for adjusting the flow rate of VOCs transferred from the VOC collection tank (200) to the mixer (701) is installed in the VOC supply line (VL2).

The VOC valve (CV) can be controlled based on the composition of the VOC transferred from the VOC collection tank (200) to the mixer (701).

For example, when the nitrogen content of the VOC transferred from the VOC collection tank (200) to the mixer (701) exceeds the reference value, the opening amount of the VOC valve (CV) is controlled to control the VOC collection tank (VOC collection tank (701). The flow rate of VOC supplied from 200) to the mixer (701) is reduced.

The reference value of the nitrogen content of the VOC transferred from the VOC collection tank (200) to the mixer (701) is that the nitrogen content of the mixed fuel mixed in the mixer (701) is the nitrogen required by the engine. The content is, for example, less than 20 mol% or less than 30 mol%.

For example, when the content of heavy hydrocarbons of VOC transferred from the VOC collection tank (200) to the mixer (701), particularly the content of heavy hydrocarbons having 10 or more carbon atoms exceeds the standard value, VOC The opening amount of the valve (CV) is adjusted to reduce the flow rate of VOC supplied from the VOC collection tank (200) to the mixer (701).

The reference value of the heavy hydrocarbon of VOC transferred from the VOC collection tank (200) to the mixer (701) is a value at which the mixed fuel mixed in the mixer (701) does not become multi-phase. possible. For example, the standard value at which the mixed fuel does not become polyphasic is that the concentration of heavy hydrocarbons having 10 or more carbon atoms contained in the VOC is less than 1 mol%.

The engine (1000) of this embodiment can be a two-stroke cycle engine. Further, the engine (1000) of the present embodiment may operate based on a diesel cycle in which high-pressure gas fuel is directly injected into the combustion chamber near the top dead center of the piston.

Further, the pressure condition of the gas fuel required by the engine (1000) of the present embodiment is about 200 bar to 420 bar, or about 250 bar to 380 bar, and preferably about 380 bar of high pressure gas fuel can be burned.

The temperature condition of the gas fuel required for the engine (1000) of the present embodiment is about 35 ° C. to 45 ° C., preferably about 45 ° C.

Further, the engine (1000) of the present embodiment may be a gas engine using 100% ethane gas, 100% natural gas, a mixture of natural gas and VOC, and VOC as fuel.

For example, the engine (1000) of the present embodiment is a ME-GIE (MAN Electronic Gas Injection Ethane) engine manufactured by MAN ES.

Further, the engine (1000) of the present embodiment uses LNG as the main fuel, and uses a mixed fuel of LNG (or natural gas) and VOC or VOC as the fuel of the engine depending on the amount of VOC generated.

That is, the ship of the present embodiment is based on a natural gas fuel ship that uses LNG as fuel in normal times.

The LNG stored in the fuel storage tank (300) is pressurized by the fuel pump (400) and is supplied to the high pressure pump (FL) via the fuel supply line (FL) connecting the fuel pump (400) and the high pressure pump (501). Transferred to 501).

The fuel pump (400) can pressurize the LNG stored in the fuel storage tank (300) to about 10 bar. However, it is not limited to this.

The high-pressure pump (501) compresses the LNG pressurized by the fuel pump (400) to the pressure of the gas fuel required by the engine (1000), that is, a high pressure of about 380 bar or more in the present embodiment, and is a vaporizer. Supply to (601).

The LNG compressed to high pressure by the high pressure pump (501) is transferred to the vaporizer (601) via the fuel supply line (FL) connecting the high pressure pump (501) and the vaporizer (601).

The vaporizer (601) converts LNG compressed to the high pressure required by the engine (1000) by the high pressure pump (501), that is, to about 380 bar in this embodiment, into natural gas (gas state or supercritical state). Vaporize.

The natural gas vaporized by the vaporizer (601) is supplied to the mixer (701) via the fuel supply line (FL) connecting the vaporizer (601) and the mixer (701).

One of the locations between the fuel pump (400) and the high-pressure pump (501), between the high-pressure pump (501) and the vaporizer (601), and between the vaporizer (601) and the mixer (701). As described above, an LNG valve (not shown) that controls the flow rate of LNG transferred from the fuel storage tank (300) to the mixer (701) can be installed.

The LNG valve can be controlled according to the amount of fuel required by the engine (1000) and the heavy hydrocarbon or nitrogen content of the VOC transferred from the VOC collection tank (200) to the mixer (701). ..

The mixer (701) of the present embodiment can be an ejector utilizing the Bernoulli effect. The ejector (701) uses a high voltage natural gas compressed up to the high voltage required by the engine (1000), that is, up to about 380 bar in the present embodiment, as a driving fluid to externally generate electric power or the like. The VOC transferred from the VOC collection tank (200) to the ejector (701) can be sucked and mixed without using power (mixing step). In the mixer (701), high-pressure natural gas and VOC are mixed in a single phase and diffusely injected.

When an ejector is used as the mixer (701) as in the present embodiment, the fluid diffusely injected into the ejector promotes mixing while forming a curved overflow, so that natural gas and VOC are not used without electric power. Can be easily and uniformly mixed.

The mixed fuel in which natural gas and VOC are mixed in the edacta (701) is supplied as the fuel for the engine (1000) via the mixed fuel supply line (ML1) connecting the edacta (701) and the engine (1000). (Supply process).

Next, the fuel supply system and the fuel supply method of the crude oil carrier according to the second embodiment of the present invention will be described with reference to FIG. This embodiment is a modification of the first embodiment described above, and unlike the first embodiment in which the mixer (701) is installed downstream of the high pressure pump (501), in the present embodiment, The difference is that the mixer (702) is installed upstream of the high pressure pump (502). Hereinafter, this difference will be mainly described, and specific description of the same member will be omitted. The same members as those in the first embodiment described above can be applied to the same members even if specific references and explanations are omitted.

The fuel supply system of the crude oil carrier according to the present embodiment is composed of one or more crude oil storage tanks (cargo tank, 100) for storing crude oil and volatile organics produced by evaporation of crude oil in the crude oil storage tank (100). A VOC collection tank (200) that collects compounds (VOC; Volatile Organic Compounds) as they are without phase change, and a fuel storage tank that stores liquefied natural gas (LNG) used as fuel for the ship's engine (1000). (300), a fuel pump (400) that pressurizes LNG stored in the fuel storage tank (300) and discharges it to the outside from the fuel storage tank (300), and a liquid state pressurized by the fuel pump (400). LNG is used as the driving fluid, and the VOC in the gaseous state transferred from the VOC collection tank (200) is sucked in to mix the LNG and VOC with the mixer (702) and the mixer (702). A high-pressure pump (502) that compresses the mixed fuel in the liquid state to the pressure range required by the engine (1000), and a vaporizer (602) that vaporizes the mixed fuel compressed by the high-pressure pump (502). LNG stored in the fuel storage tank (300) was vaporized by natural gas vaporized using a vaporizer (602), VOC collected in a VOC collection tank (200), or vaporizer (602). It includes an engine (1000) that uses mixed fuel as fuel.

The VOC collection line (VL1) connects the crude oil storage tank (100) and the VOC collection tank (200), and the VOC discharged from the crude oil storage tank (100) passes through the VOC collection line (VL1). Transferred to VOC collection tank (200).

The VOC generated by evaporation of crude oil from the crude oil storage tank (100) is in a gaseous state, is transferred in the gaseous state via the VOC collection line (VL1), and is stored in the VOC collection tank (200) in the gaseous state. Will be done.

Similarly, the VOC stored in the VOC collection tank (200) in the present embodiment is stored in the VOC collection tank (200) while being transferred from the crude oil storage tank (100) to the VOC collection tank (200). During this time, no phase change occurs while being transferred from the VOC collection tank (200) to the mixer (702) via the VOC supply line (VL2).

Further, in the fuel supply system according to the present embodiment, a pretreatment device for removing impurities such as water and nitrogen from the VOC transferred from the crude oil storage tank (100) to the VOC collection tank (200) is not installed. That is, the VOC is transferred from the crude oil storage tank (100) to the VOC collection tank (200) without any pretreatment (without a pretreatment step).

The gaseous VOCs collected in the VOC collection tank (200) do not change phase via the VOC supply line (VL2) connecting the VOC collection tank (200) and the mixer (702). Transferred to (702).

A VOC valve (CV) that regulates the flow rate of VOCs transferred from the VOC collection tank (200) to the mixer (702) is installed in the VOC supply line (VL2).

The VOC valve (CV) can be controlled based on the composition of the VOC transferred from the VOC collection tank (200) to the mixer (702). As the control method, the same method as in the first embodiment can be applied.

The engine (1000) of the present embodiment is a two-stroke (2-stroke) cycle engine and can operate on the basis of a diesel cycle.

The LNG stored in the fuel storage tank (300) is pressurized by the fuel pump (400) and is connected to the fuel pump (400) and the mixer (702) via the fuel supply line (FL). Transferred to 702).

The mixer (702) of the present embodiment can be an ejector utilizing the Bernoulli effect. The eductor (702) uses the liquid LNG pressurized by the fuel pump (400) as the working fluid, and can inhale the gaseous VOC transferred from the VOC collection tank (200) to the eductor (702). it can.

The LNG pressurized by the fuel pump (400) can be about 10 barg or more. However, it is not limited to this. The fuel pump (400) compresses the LNG with a mixer (702) to a pressure sufficient to condense the VOC.

In the mixer (702), LNG and VOC are mixed in a single phase and diffusely injected. VOCs in a gaseous state are diffused and jetted with LNG in a compressed liquid state, condensed, and mixed with LNG in a liquid state.

The mixed fuel in which LNG and VOC are mixed by the ejector (702) is transferred to the high pressure pump (502) via the mixed fuel supply line (ML2) connecting the ejector (702) and the high pressure pump (502). ..

The high-pressure pump (502) vaporizes the mixed fuel of LNG and VOC mixed by the mixer (702) by compressing it to the pressure of the gas fuel required by the engine (1000), that is, to a high pressure of about 380 bar or more. Supply to the vessel (602).

The mixed fuel compressed to a high pressure by the high-pressure pump (502) is transferred to the vaporizer (602) via the mixed fuel supply line (ML2) connecting the high-pressure pump (502) and the vaporizer (602).

The vaporizer (602) vaporizes the mixed fuel compressed by the high pressure pump (502) to the high pressure required by the engine (1000), that is, to about 380 bar in this embodiment, to a gaseous or supercritical state.

The mixed fuel gas vaporized by the vaporizer (602) is supplied to the engine (1000) via the mixed fuel supply line (ML2) connecting the vaporizer (602) and the engine (1000).

An LNG valve (not shown) that controls the flow rate of LNG transferred from the fuel storage tank (300) to the mixer (702) shall be installed between the fuel pump (400) and the mixer (702). Can be done.

Next, the fuel supply system and the fuel supply method of the crude oil carrier according to the third embodiment of the present invention will be described with reference to FIG. This embodiment is a modification of the second embodiment described above, and unlike the second embodiment in which the mixer (702) is provided with an ejector, the mixer (900) is provided with a condenser and a VOC compressor. It differs in that it further includes (800). Hereinafter, this difference will be mainly described, and specific description of the same member will be omitted. The same members as those in the second embodiment described above can be applied to the same members even if specific references and explanations are omitted.

The fuel supply system of the crude oil carrier according to the present embodiment is composed of one or more crude oil storage tanks (cargo tank, 100) for storing crude oil and volatile organic compounds produced by evaporation of crude oil in the crude oil storage tank (100). A VOC collection tank (200) that collects volatile organic compounds (VOCs) as they are without phase change, and a fuel storage tank that stores liquefied natural gas (LNG) used as fuel for ship engines (1000). (300), a fuel pump (400) that pressurizes the LNG stored in the fuel storage tank (300) and discharges it from the fuel storage tank (300) to the outside, and an LNG pressurized by the fuel pump (400). A mixer (900) that mixes VOCs transferred from the VOC collection tank (200), and a VOC compressor (800) that compresses VOCs supplied from the VOC collection tank (200) to the mixer (900). A high-pressure pump (503) that compresses the liquid mixed fuel mixed by the mixer (900) to the pressure range required by the engine (1000), and a mixed fuel compressed by the high-pressure pump (503). A vaporizer (603) to vaporize and a natural gas obtained by vaporizing LNG stored in a fuel storage tank (300) using a vaporizer (603), a VOC collected in a VOC collection tank (200), or It includes an engine (1000) that uses a mixed fuel vaporized by a vaporizer (603) as a fuel.

The VOC collection line (VL1) connects the crude oil storage tank (100) and the VOC collection tank (200), and the VOC discharged from the crude oil storage tank (100) passes through the VOC collection line (VL1). Transferred to VOC collection tank (200).

The VOC generated by evaporation of crude oil in the crude oil storage tank (100) is in a gaseous state, is transferred in the gaseous state via the VOC collection line (VL1), and is stored in the VOC collection tank (200) in the gaseous state. Will be done.

Similarly, in the present embodiment, the VOC stored in the VOC collection tank (200) is transferred to the VOC collection tank (200) while being transferred from the crude oil storage tank (100) to the VOC collection tank (200). During storage, no phase change occurs during transfer to the mixer (900).

Further, in the fuel supply system according to the present embodiment, the VOC transferred from the crude oil storage tank (100) to the VOC collection tank (200) and the water content transferred from the VOC collection tank (200) to the mixer (900). No pretreatment equipment is installed to remove impurities such as nitrogen and nitrogen.

The gaseous VOC collected in the VOC collection tank (200) is passed through the VOC supply line (VL3) connecting the VOC collection tank (200) and the VOC compressor (800) to the VOC compressor (800). Will be transferred to.

A VOC valve (CV) that regulates the flow rate of VOCs transferred from the VOC collection tank (200) to the VOC compressor (800) is installed in the VOC supply line (VL3).

The VOC valve (CV) can be controlled based on the composition of the VOC transferred from the VOC collection tank (200) to the mixer (900). As the control method, the same method as that of the first embodiment described above can be applied.

The engine (1000) of the present embodiment is a two-stroke (2-stroke) cycle engine, and can operate on the basis of a diesel cycle.

The LNG stored in the fuel storage tank (300) is pressurized by the fuel pump (400) and is connected to the fuel pump (400) and the mixer (900) via a fuel supply line (FL). Transferred to 900).

The mixer (900) of the present embodiment is a condenser (condensor) that mixes LNG pressurized by the fuel pump (400) and VOC compressed by the VOC compressor (800) to condense the compressed VOC. possible.

The LNG pressurized by the fuel pump (400) can be about 10 barg or more. However, it is not limited to this. The fuel pump (400) compresses LNG with a mixer (900) to a pressure sufficient to condense VOCs.

Further, the VOC compressor (800) can compress the VOC at substantially the same pressure (equivalent pressure) as the pressure at which the compression pump (400) compresses LNG.

The liquid mixed fuel in which LNG and VOC are mixed in the mixer (900) is delivered to the high pressure pump (503) via the mixed fuel supply line (ML3) connecting the mixer (900) and the high pressure pump (503). ).

The high-pressure pump (503) vaporizes the mixed fuel of LNG and VOC mixed by the mixer (900) by compressing it to the pressure of the gas fuel required by the engine (1000), that is, to a high pressure of about 380 bar or more. Supply to the vessel (603).

The mixed fuel compressed to a high pressure by the high-pressure pump (503) is transferred to the vaporizer (603) via the mixed fuel supply line (ML3) connecting the high-pressure pump (503) and the vaporizer (603).

The vaporizer (603) vaporizes the mixed fuel compressed by the high pressure pump (503) to the high pressure required by the engine (1000), that is, to about 380 bar in this embodiment, in a gaseous or supercritical state.

The mixed fuel gas vaporized by the vaporizer (603) is supplied to the engine (1000) via the mixed fuel supply line (ML3) connecting the vaporizer (603) and the engine (1000).

An LNG valve (not shown) that controls the flow rate of LNG transferred from the fuel storage tank (300) to the mixer (900) shall be installed between the fuel pump (400) and the mixer (900). Can be done.

Conventional VOC processing systems include refrigeration cycles to liquefy VOCs and then store them in storage tanks, or liquefied VOCs, that is, some engines that can vaporize LVOCs and use VOCs as fuel. Was supplying to. Since LVOC is a liquefied product of VOC, it contains a relatively high concentration of heavy hydrocarbons as compared with that before liquefaction, and particularly contains heavy hydrocarbons having a large number of carbon atoms.

On the other hand, SVOCs containing very low boiling point gases that were not liquefied in the process of liquefying VOCs, such as nitrogen, low carbon hydrocarbons such as methane and ethane, are separated separately and used as fuel for boilers and gas turbines. I was using it.

Therefore, the conventional VOC processing system consumes very high power consumption in the refrigeration cycle and the like, requires a lot of space, and is expensive because it is composed of an expensive package. Further, the VOC component changes according to the residence time in the crude oil storage tank, and the longer the residence time, the higher the content of the heavy hydrocarbon component, which causes a problem that the fuel supply is not smooth.

Further, since most engines cannot burn not only SVOCs having a high nitrogen content but also LVOCs having a high content of heavy hydrocarbons, a method of reforming VOCs with methane and supplying them with fuel has also been proposed. However, since the reforming reaction itself requires a large amount of heat source, the volume of the reforming reaction system equipment is large, and the safety is not guaranteed when it is applied to a ship, it is a heavy burden to install it on a ship.

However, in the present invention, the VOC pretreatment step, the VOC reforming step, and the VOC liquefaction step are omitted, and VOC and LNG are mixed and supplied as fuel for the engine to consume power and install space (installation). The cost due to (area) and the burden of physical space can be significantly reduced. In addition, it is environmentally friendly because all harmful VOCs can be recovered and used as fuel without releasing them into the atmosphere.

The embodiment according to the present invention has been described above. In addition to the embodiments described above, the fact that the present invention can be embodied in other particular embodiments without departing from its spirit or category is self-evident to those who have ordinary knowledge of the art. Therefore, the embodiments described above should be considered to be exemplary rather than limiting, and thus the invention is not limited to the description described above, but the categories of the appended claims and their equivalents. It can be changed within the range of.

100: Crude oil storage tank 200: VOC collection tank 300: Fuel storage tank 400: Fuel pump 501, 502, 503: High pressure pump 601, 602, 603: Vaporizer 701, 702, 900: Mixer 800: VOC compressor 1000 : Engine VL1: VOC collection line

Claims (12)

A VOC collection tank that collects VOCs (Volatile Organic Compounds) in a gaseous state discharged from a crude oil storage tank as they are without changing the phase.
A fuel storage tank that stores LNG (Liquefied Natural Gas) used as fuel for the engine,
A fuel pump that pressurizes and discharges LNG stored in the fuel storage tank, and
It is provided with a mixer that mixes LNG in a liquid state pressurized by the fuel pump and VOC in a gaseous state discharged from the VOC collection tank.
The engine is a two-stroke diesel cycle engine.
A mixed fuel supply line that connects the mixer and the engine and supplies the mixed fuel mixed by the mixer to the engine.
The VOC collection tank is connected to the mixer, and a VOC supply line for transferring VOCs containing nitrogen and heavy hydrocarbon components from the VOC collection tank to the mixer is further provided. Fuel supply system for crude oil carriers. A high-pressure pump that compresses the liquid mixed fuel mixed by the mixer to the high pressure required by the engine.
Further provided with a vaporizer for vaporizing the mixed fuel compressed by the high-pressure pump.
The fuel supply system for a crude oil carrier according to claim 1, wherein the mixed fuel in a gaseous state vaporized by the vaporizer is supplied as fuel for the engine via the mixed fuel supply line. The first aspect of the present invention is characterized by further comprising a VOC valve which is installed in the VOC supply line and whose opening degree is controlled according to the nitrogen content of the VOC supplied from the VOC collection tank to the mixer. The fuel supply system for the crude oil carrier described. The crude oil carrier according to claim 3, further comprising a control unit that controls the opening degree of the VOC valve so that the nitrogen content of the mixed fuel mixed by the mixer is less than 30 mol%. Fuel supply system. The fuel for a crude oil carrier according to claim 1, wherein the engine is a gas engine capable of using 100% ethane gas, 100% natural gas, a mixture of natural gas and VOC, and VOC as fuel. Supply system. The fuel supply system for a crude oil carrier according to claim 2 or 5, wherein the high-pressure pump compresses the mixed fuel to 200 bar to 420 bar. The fuel supply system for a crude oil carrier according to claim 1, wherein the mixer is an ejector using the liquid LNG as a working fluid. Further provided with a VOC collection line that connects the crude oil storage tank and the VOC collection tank and transfers VOCs containing nitrogen and heavy hydrocarbon components from the crude oil storage tank to the VOC collection tank.
The VOC is characterized in that it is transferred from the crude oil storage tank to the VOC collection tank and from the VOC collection tank to the mixer without performing a pretreatment for removing water and nitrogen. The fuel supply system for the crude oil carrier according to 1. A process of collecting and storing VOCs (Volatile Organic Compounds) in a gaseous state containing nitrogen and heavy hydrocarbon components discharged from a crude oil storage tank in a gaseous state without phase change.
The process of compressing LNG used as engine fuel and
A mixing step of discharging the stored VOC and mixing it with the compressed liquid LNG.
A method for supplying fuel to a crude oil carrier, which comprises a supply step of supplying a mixed fuel in which LNG and VOC are mixed to a diesel cycle engine in two strokes. The method for supplying fuel to a crude oil carrier according to claim 9, wherein in the mixing step, the LNG is used as a working fluid and the VOC in a gaseous state is sucked and mixed. The supply step includes a step of further compressing the mixed fuel to a high pressure required by the engine and a step of vaporizing the mixed fuel compressed to the high pressure, and the vaporized gaseous state mixed fuel is said to be said. The method for supplying fuel to a crude oil carrier according to claim 9, wherein the fuel is supplied to an engine. 9. The mixing step comprises adjusting the flow rate of VOC in a gaseous state to be mixed with the compressed LNG so that the nitrogen content of the mixed fuel is less than 30 mol%. How to supply fuel for crude oil carriers.

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