KR20210023027A - Lng bunkering platform - Google Patents

Abstract

A liquefied natural gas (LNG) bunkering platform is disclosed. According to an embodiment of the present invention, an LNG bunkering platform may comprise: a platform which has a storage tank for storing LNG and is located in the sea; a loading facility installed on the platform and bunkering when berthing other ships; a liquefied gas regasification and cooling and heat power generation facility mounted on the platform and for self-power procurement; and a boil off gas (BOG) transmission means for transmitting BOG generated in the process of supplying LNG to land.

Description

LNG bunkering platform {LNG BUNKERING PLATFORM}

The present invention relates to an LNG bunkering platform, and more specifically, an LNG tank of a facility consisting of a FSRU or FSU, a combination of an LNG ship and a regasification equipment installed on the platform as the main storage, and an LNG propulsion ship or an LNG carrier from the side It relates to an LNG bunkering platform that can be docked.

Fuels used in ships include diesel, heavy oil, MDO (Marine Diesel Oil), and MFO (Marine Fuel Oil). As regulations on environmental pollution are strengthened, the use of LNG as a fuel for lathes is increasing due to the introduction of clean energy. And, as a result, the demand for LNG from ships is increasing.

The conventional bunkering method of LNG-propelled ships is a form of receiving LNG by berthing on a bunkering-only ship or onshore, and has the following problems.

First, LNG-propelled ships and LNGs have difficulties such as having to operate according to specific ships or to create separate structures because there is a restriction mainly due to the level of the ship or onshore.

Second, there is a difficulty in resolving the entire amount of excessive BOG (excessive boil off gas) treatment that occurs in the process of receiving LNG at the place where LNG is delivered. Therefore, in order to reduce the occurrence of BOG, expensive reliquefaction equipment is installed or LNG delivery time is controlled for a long period of time.

Third, the existing LNG bunkering ships and land supply have a small capacity and must be supplied several times, so a large amount of time is required, and a bunkering facility with a large-capacity LNG tank is required to supply the entire amount to small and large LNG-propelled ships.

The present invention provides an LNG bunkering platform capable of simultaneously supplying LNG to a plurality of LNG vessels.

The present invention provides an LNG bunkering platform capable of mooring and fendering to enable berthing of other ships.

The present invention provides an LNG bunkering platform capable of height adjustment.

The problem to be solved by the present invention is not limited to the problems mentioned above. Other technical problems not mentioned will be clearly understood by those of ordinary skill in the art from the following description.

According to an aspect of the invention, having a storage tank for storing LNG, a platform located on the sea; A loading facility installed on the platform for bunkering when berthing other ships; A regasification facility mounted on the platform and for self-powered cooling and heat generation; And an LNG bunkering platform including a BOG transmission means for transmitting the BOG generated in the process of supplying the LNG to the land may be provided.

In addition, the BOG transmission means may include a high pressure compressor for compressing and transmitting the BOG at high pressure.

In addition, the BOG transmission means may compress the BOG with a low pressure compressor and transmit it to land through recondensation in the regasification facility for cold and heat power generation.

In addition, the platform may be capable of mooring and fendering that other ships can berth.

In addition, a plurality of support columns vertically erected at intervals from each other on the platform; And a jack-up device installed on the platform and the support pillar to raise the platform along the support pillar.

In addition, the loading facility may be provided so that the height is adjustable on the platform.

According to an embodiment of the present invention, it is possible to supply LNG to a plurality of LNG vessels at the same time.

According to an embodiment of the present invention, it is possible to adjust the height according to large and small ships.

The effects of the present invention are not limited to the above-described effects. Effects not mentioned will be clearly understood by those of ordinary skill in the art from the present specification and the accompanying drawings.

1 is a plan configuration diagram of an LNG bunkering platform according to an embodiment of the present invention.
FIG. 2 is a view showing bunkering of an LNG-propelled ship in the LNG bunkering platform shown in FIG. 1.
3 is a view showing another example of the LNG bunkering platform shown in FIG.
4 is a view showing another example of the LNG bunkering platform shown in FIG.
5 is a view showing another example of the LNG bunkering platform shown in FIG.
6 is a block diagram of the liquefied gas regasification and cold heat power generation facility shown in FIG. 3.
7 is a graph showing a temperature change according to a heat flow amount of a mixed refrigerant used in a ship's liquefied gas regasification facility according to an embodiment of the present invention.
8 is a diagram showing the safety class classification criteria of refrigerant.
9 is a graph showing the temperature change characteristics according to the heat flow amount of the mixed refrigerant for each mixing ratio of the mixed refrigerant used in the liquefied gas regasification and cold heat power generation facilities.
10 is a graph illustrating a refrigerant characteristic curve showing the state of the heat medium according to the enthalpy and pressure of the heat medium.

Other advantages and features of the present invention, and a method of achieving them will become apparent with reference to embodiments to be described later in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, and the present invention is only defined by the scope of the claims. Even if not defined, all terms (including technical or scientific terms) used herein have the same meaning as commonly accepted by universal technology in the prior art to which this invention belongs. A general description of known configurations may be omitted so as not to obscure the subject matter of the present invention. In the drawings of the present invention, the same reference numerals are used as much as possible for the same or corresponding configurations. In order to help the understanding of the present invention, some configurations in the drawings may be somewhat exaggerated or reduced.

The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the present application, terms such as "comprise", "have" or "have" are intended to designate the existence of features, numbers, steps, actions, components, parts, or combinations thereof described in the specification. It is to be understood that the possibility of the presence or addition of other features, numbers, steps, actions, components, parts, or combinations thereof, or any further features, is not preliminarily excluded.

1 is a plan configuration diagram of an LNG bunkering platform according to an embodiment of the present invention, and FIG. 2 is a view showing bunkering of an LNG-propelled ship in the LNG bunkering platform shown in FIG. 1.

The LNG bunkering platform according to an embodiment of the present invention has an LNG tank of a facility consisting of a combination of FSRU or FSU, an LNG ship and a regasification equipment installed on the platform platform as the main storage, and the LNG propulsion ship or LNG carrier can berth from the side. It is a structure that can be used.

1 and 2, the LNG bunkering platform 200 according to this embodiment includes a platform 210, a jack-up leg 220, a loading facility 230, a regasification facility 240, and a BOG transmission means 270. ) Can be included.

The platform 210 is provided so as to be floating on the sea, and various facilities, etc. may be installed on the upper part. As an example, the platform 210 has a rectangular shape, and an eyepiece means 212 may be provided on four surfaces so that the ship 10 can be eyepiece. As another example, the platform may be provided in a triangular, polygonal or circular shape. An FSRU, an LNG ship, an LNG carrier, etc. may be contacted to the platform 210.

The platform 210 may be provided with an LNG storage tank 220 that receives and stores LNG. LNG stored in the LNG storage tank 280 may be supplied to the LNG vessel 10 through the loading facility 230 which is a bunkering device. The loading facility 230 is installed in plural on the side where the ship is berthed, and a hose 232 for supplying LNG from the LNG storage tank 280 to the LNG ship 20 and a crane 234 supporting the hose 232 It may include, and other various methods capable of transporting LNG may be applied. The loading facility 230 may be provided to enable its own height adjustment for bunkering when berthing the LNG vessel.

The platform 210 is provided with liquid lines 202 and vapor lines 204 connected to the LNG storage tank 280, and these are provided to the LNG vessel 10 through the loading facility 230. Can be connected.

Here, the LNG ship 10 refers to all ships receiving LNG, such as a ship using LNG as a fuel or an LNG carrier that stores and transports LNG.

In the present invention, LNG is described as a bunkering fuel, but it can be used not only for LNG but also for bunkering of fuels such as HFO (Heavy Fuel Oil).

The berthing means 212 may include mooring ropes 214 and fenders 216 for binding and mooring the vessel.

The fenders 216 may be installed on the side of the platform 210 at predetermined intervals. The fenders 216 may be provided to reduce an impact applied to the ship due to a collision or the like when the ship to be berthed with the platform 210 is moored to the side of the platform 210.

Meanwhile, jack-up legs 220 for fixing the platform 210 to the sea may be installed on the platform 210. The jack-up legs 220 are installed to move up and down on the platform 210 and have a post shape, and thus have an appropriate length according to the depth of the seabed to which the platform 210 is to be fixed.

The jack-up leg 220 is a jack-up device that is installed on the support pillar 222 and the platform 210 and the support pillar 222 vertically erected on the platform 210 to raise the platform 210 along the support pillar 222 (224) may be included.

The jack-up leg 220 may be configured in plural in order to balance the platform 210. For example, the jack-up leg 220 is preferably made of four so as to be positioned at each corner of the platform 210.

In the process of installing the platform 210 on the sea level, the support columns 222 of the jack-up legs 220 are lowered toward the sea floor to fix the lower end of the support column 222 to the sea floor, and the platform 210 is jack-up. Installation may be made by moving the leg 220 upward and exposing it to the sea level.

As described above, the LNG bunkering platform 200 of the present invention can adjust the height of the platform according to the vessel 10 (large or small) to be contacted, thereby solving the problem due to the difference in step between the platform and the LNG vessel. .

A regasification device 240 for regasifying LNG stored in the LNG storage tank 280 may be installed on the platform 210. The liquefied gas regasified in the regasification device 240 is sent to a demander on land through the onshore supply line 248. A description of the regasification device 240 will be omitted.

BOG generated in the process of supplying LNG to the ship is transmitted to the land through the BOG transmission means 270.

In general, when using the ship to ship method (Ship to Ship), for one LNG bunkering ship that supplies LNG, one ship using LNG as fuel is docked using a tug boat. LNG can be supplied. In other words, one LNG ship berths for one LNG bunkering ship to receive LNG.In this case, a large number of tugs are required for each small LNG bunkering ship, and the crew must also be on board, so operation requires a lot of cost. It is done.

However, in the LNG bunkering platform of the present invention, it is possible to simultaneously refuel several LNG vessels 10.

3 is a block diagram of an LNG bunkering platform according to another embodiment of the present invention.

In describing the embodiment of FIG. 3, duplicate descriptions of components that are the same as or corresponding to the above-described embodiment may be omitted.

The LNG bunkering platform 200a according to the embodiment of FIG. 3 is different from the above-described embodiment in that it has a liquefied gas regasification and cooling and heat power generation facility 100 for self-power procurement.

The liquefied gas regasification and cold heat power generation facility 100 regasifies liquefied gas such as liquefied natural gas (LNG) and liquefied petroleum gas (LPG), By supplying fuel gas such as petroleum gas to demanders on land, and generating electricity using the cold heat of the liquefied gas in the heat exchange process to regasify the liquefied gas, it is possible to procure the power of the LNG bunkering platform 100a itself.

4 is a block diagram of an LNG bunkering platform according to another embodiment of the present invention.

In describing the embodiment of FIG. 4, duplicate descriptions of components that are the same as or corresponding to the above-described embodiment may be omitted.

The LNG bunkering platform 200b according to the embodiment of FIG. 4 is different from the above-described embodiment in that a high pressure compressor 290 is added and transmitted to land for BOG processing of an LNG vessel. That is, excessive BOG (excessive boil off gas) generated in the process of receiving LNG from an LNG vessel can be compressed by a high pressure compressor and then transmitted to land.

5 is a block diagram of an LNG bunkering platform according to another embodiment of the present invention.

In describing the embodiment of FIG. 5, duplicate descriptions of components that are the same as or corresponding to the above-described embodiment may be omitted.

The LNG bunkering platform 200c according to the embodiment of FIG. 5 is implemented as described above in that it can process BOG through the addition of a low-pressure compressor 292 and regasification of liquefied gas and the recondenser inside the cooling and heat generation facility 100. There is a difference from the example.

6 is a block diagram of the liquefied gas regasification and cold heat power generation facility shown in FIG. 2.

The liquefied gas regasification and cold heat power generation facility of a ship according to an embodiment of the present invention uses a mixed refrigerant in which refrigerants having a boiling point difference of at least 20°C or more are mixed, and between the dew point temperature and the boiling point temperature in a pressure range of 10 to 20 barg. By vaporizing the liquefied gas using a mixed refrigerant having a difference of 10° C. or more, the temperature is increased during a phase change process in which the mixed refrigerant is vaporized in the evaporator, and the vaporization efficiency of the liquefied gas can be increased.

6, the liquefied gas regasification and cold heat power generation system 100 according to the present embodiment recovers liquefied gas such as liquefied natural gas (LNG) and liquefied petroleum gas (LPG). In order to increase power generation efficiency by supplying fuel gas such as natural gas (NG) and petroleum gas to customers, and generating power by using the cold heat of the liquefied gas in the heat exchange process to regasify the liquefied gas. Can be provided.

In one embodiment, the liquefied gas regasification and cold heat power generation system 100 includes a liquefied gas transfer line 248, a vaporizer 120, a heat medium circulation line 130, a pump 140, a heat medium tank 150, an evaporator ( 160), an expansion turbine 170, and a first heat exchanger 180. Here, it may be referred to as an organic Rankine cycle that is composed of an evaporator, an expansion turbine, a vaporizer, a heat medium tank, and a pump in order on the heat medium circulation line through which the heat medium is circulated.

The liquefied gas transfer line 248 may be provided to receive liquefied gas from the LNG storage tank 280, vaporize the supplied liquefied gas, and transmit it to a demander on land.

For example, a heat medium (mixed refrigerant) in which two or more non-combustible refrigerants are mixed may be circulated in the heat medium circulation line 130. In an embodiment, the ship's liquefied gas regasification system 100 may be configured with a single heat medium circulation line 130.

The heat medium circulates the pump 140, the evaporator 160, the expansion turbine 170, and the carburetor 120 through the heat medium circulation line 130. In order to increase the temperature of the mixed refrigerant in the process of vaporizing the mixed refrigerant in the evaporator 160 and changing the phase from liquid to gas, the heating medium is provided as a refrigerant mixed with refrigerants having a boiling point difference of at least 20°C, and mixed at the same time. The mixing ratio of the refrigerants may be set so that the difference between the dew point temperature and the boiling point temperature of the mixed refrigerant is 10°C or more in the 10 ~ 20 barg pressure (vapor pressure) section of the refrigerant.

The high-pressure booster pump 110 may pressurize and supply cryogenic liquefied gas from a liquefied gas storage tank or a buffer tank to the liquefied gas transfer line 248 in consideration of the pressure required at the place of use. The liquefied gas pressurized by the high-pressure booster pump 110 may be vaporized and heated through the vaporizer 120 to be supplied to a customer on land.

A heat medium for vaporizing liquefied gas is circulated in the heat medium circulation line 130. The heat medium may be, for example, a fluid and/or a mixture thereof shown in Table 1 below.

ethane Propane I-butane N-butane R13B1 R143a R134a R152a R22 R12 R13 R125 R500 R502 R507 R114 R14 R23 R744

The heat medium circulates through the heat medium tank 150, the pump 140, the evaporator 160, the expansion turbine 170, and the carburetor 120 in sequence along the heat medium circulation line 130. The vaporizer 120 is The liquefied gas in the liquefied gas transfer line is regasified using the thermal energy and latent heat of the heating medium.

The heat medium tank 150 stores the heat medium discharged from the vaporizer 120. The heat medium tank 150 absorbs the pressure change of the heat medium according to the operating conditions, and maintains the heat medium in a set temperature range so that the heat medium can be operated in a predetermined pressure range. The heat medium tank 150 may be provided as an expansion tank. The heat medium tank 150 absorbs the pressure change of the heat medium according to the operating conditions, and maintains the heat medium recovered to the heat medium tank 150 in a set temperature range so that the heat medium tank 150 can be operated in a predetermined pressure range. Two or more types of liquefied refrigerants may be stored in the heat medium tank 150.

The pump 140 pressurizes the heat medium discharged from the heat medium tank 150 and circulates it in the heat medium circulation line 130. The pump 140 may be installed at a rear end of the heat medium tank 150 and a front end of the evaporator 160, and may be configured to pressurize the heat medium and supply it to the evaporator 160.

A first pressure sensor P1 and a first temperature sensor T1 are installed in the heat medium circulation line 130 between the vaporizer 120 and the pump 140. The first pressure sensor P1 and the first temperature sensor T1 measure the pressure and temperature of the liquid heat medium discharged from the vaporizer 120.

The evaporator 160 vaporizes the liquid heat medium discharged from the vaporizer 120 and circulating through heat exchange with a heat source. The heat source may be provided by seawater, steam, waste heat from an engine in a ship, or the like. For example, the evaporator 160 may evaporate the heat medium by heat exchange with a heat source supplied through the seawater line 90. The heat source may be supplied to the evaporator 160 through the seawater line 90 by a seawater pressure pump (not shown). The inlet temperature of the evaporator of the heat source may be about 14° C., and the discharge temperature may be about 7 to 8° C. The evaporator 160 may be manufactured to withstand the pressure of the heating medium (eg, 10 to 20 barg vapor pressure).

When the evaporator 160 is made of, for example, a plate type heat exchanger (PHE) made of titanium, in order to use titanium with a thickness of 0.6 mm or less as a heat exchange plate, the design pressure (vapor pressure) of the heat medium is 16. It should be less than or equal to barg. If a titanium plate having a thickness of 0.7mm or more is used to increase the design pressure, the cost of equipment is greatly increased because the price increases by more than 10 times compared to a plate having a thickness of 0.6mm.

In the case of the mixed refrigerant, the dew point and the boiling point of the mixed refrigerant are changed according to the type of the mixed refrigerants and the mixing ratio of the refrigerants, thereby affecting the temperature change characteristics of the mixed refrigerant when the phase changes, as well as in the evaporator 160. During the phase change process, the pressure (vapor pressure) of the mixed refrigerant also changes. Accordingly, it is necessary to select the types of refrigerants and set the mixing ratio (weight ratio) so that desirable temperature change characteristics can be realized in the phase change section of the mixed refrigerant while minimizing the equipment cost of the evaporator 160.

In an embodiment of the present invention, in order to increase the temperature of the mixed refrigerant during the phase change of the heat medium in the evaporator 160, the liquefied gas may be regasified using a heat medium in which refrigerants having a boiling point difference of 20° C. or more are mixed. In addition, at a pressure of about 10 to 20 barg, the difference between the dew point temperature and the boiling point temperature of the heating medium is at least 10°C, while the pressure of the heating medium is about 20 barg or less (more preferably Is 16 barg or less), the mixing ratio (weight ratio) of the refrigerants may be set.

For example, the heating medium may include a first refrigerant and a second refrigerant having a boiling point lower than that of the first refrigerant by 20° C. or more. From the viewpoint of increasing the effect of increasing the temperature of the heating medium during the phase change of the heating medium in the evaporator 160, the boiling point of the second refrigerant is preferably 30° C. or more lower than the boiling point of the first refrigerant. 2 The difference in boiling point of the refrigerant is more preferably 50°C or higher.

The expansion turbine 170 is a device that generates electricity from the generator 174 by rotating the turbine 172 when a high-pressure fluid (vaporized heat medium) expands. For example, the expansion turbine 170 is installed between the evaporator 160 and the carburetor 120. The expansion turbine 170 generates power by the power of the heat medium vaporized by the evaporator 160.

A second pressure sensor P2 and a second temperature sensor T2 are installed between the evaporator 160 and the turbine 170. The second pressure sensor P2 and the second temperature sensor T2 measure the pressure and temperature of the heat medium vaporized in the evaporator 160.

A third temperature sensor T3 is installed at the rear end of the vaporizer 120. The third temperature sensor T3 measures the temperature of the liquefied gas vaporized by the vaporizer 120.

The flow rate of the heating medium can be controlled according to the measured values of the first temperature sensor (T1), the first pressure sensor (P1), the second temperature sensor (T2), the second pressure sensor (P2), and the third temperature sensor (T3). I can.

Rankine cycle is applied to the cycle for recovering the cold heat of the liquefied gas. That is, the low temperature liquid heat medium is pressurized through the pump 140, and then vaporized and heated in the evaporator 160 through a heat source. Thereafter, a pressure drop occurs through the expansion turbine 170 for power generation, and thereafter, the low-pressure refrigerant is liquefied again through the vaporizer 120 and circulated.

When the Rankine cycle is applied, since there is a restriction to satisfy the gas temperature and pressure conditions required by the customer, the cold heat that can be recovered from the liquefied gas may be significantly reduced. Since the efficiency of cooling and heat generation depends on the type, pressure and flow rate of the heating medium, it is necessary to maximize the efficiency of cooling and heat generation by optimizing the pressure and flow rate of the pressurized heating medium.

The flow rate and pressure of the heat medium may be determined based on the temperature and pressure of the heat medium discharged from the vaporizer 120, the temperature of the heat source used in the evaporator 160, the pressure point of the heat medium, and the temperature of the gas sent to the customer.

On the other hand, in consideration of the characteristic that the higher the temperature of the heat medium, the higher the pressure that can be operated while maintaining the gaseous state, it is necessary to raise the heat medium to the maximum pressure. However, there is a limitation in that the temperature of the liquefied gas vaporized by heat exchange with the heat medium in the vaporizer 120 must be adjusted to a temperature required by the customer.

Because of this, there may be restrictions on the pressure condition of the heating medium. By providing the first heat exchanger 180 to solve this limitation, the pressure drop of the heating medium is changed to the maximum to increase the amount of heat generation and at the same time You can adjust the gas temperature.

The first heat exchanger 180 receives a part of the heat medium vaporized by the evaporator 160 through the first heat source supply line 182. The first heat source supply line 182 may be branched from the front end of the expansion turbine 170 to pass through the first heat exchanger 180 and then connected to the carburetor 120.

The first heat exchanger 180 receives the heat medium vaporized by the evaporator 160 through the first heat source supply line 182, and heats the vaporized liquefied gas by exchanging heat with the liquefied gas vaporized by the vaporizer 120. It is configured to let.

The heat medium supplied through the first heat source supply line 180 may be designed to be liquefied by heat exchange with the liquefied gas vaporized in the first heat exchanger 180 and supplied to the front end (or the rear end) of the vaporizer 120. .

A fifth pressure sensor (P5) and a fifth temperature sensor (T5) are installed in the first heat source supply line 182, and the flow rate and pressure of the heat medium supplied to the first heat exchanger 220 are determined by a third temperature sensor (T3). ), the fourth temperature sensor T4, the fifth pressure sensor P5, and the fifth temperature sensor T5.

The flow rate ratio of the heat medium passing through the vaporizer 120 and the first heat exchanger 180 may be determined in consideration of the maximum temperature at which the heat medium discharged from the first heat exchanger 180 can change into a liquid phase. The pump 140 or the first flow rate control valve 132 may be controlled according to the pressure and flow rate of the heat medium determined through this process. The pump 140 and the first flow rate control valve 132 may be controlled by the controller 290.

According to this embodiment, by using the heat medium heated by the heat source of the evaporator 160 as a heat source of the first heat exchanger 180, without generating a separate heat source with seawater, steam, atmosphere, and waste heat in the vessel, The system can be miniaturized and the heat source line can be simplified.

7 is a graph showing the temperature change according to the heat flow amount of the mixed refrigerant used in the regasification of liquefied gas and the cold heat power generation system of a ship according to an embodiment of the present invention.

In FIG. 7, the horizontal axis represents the heat flow amount of fluids (seawater, LNG, mixed refrigerant), and the vertical axis represents the temperature of the fluids. The line marked'SW' is a graph of temperature change according to the heat flow of seawater, and the line marked'LNG' is a graph of temperature change according to the heat flow of liquefied natural gas.

According to the present embodiment, refrigerants having a large difference in boiling point are used as the mixed refrigerant, and in the temperature change graph according to the heat flow amount of the mixed refrigerant, the temperature gliding section in which the temperature increases when the phase change vaporized in the liquid state (A) appears, thereby satisfying the condition of the minimum temperature difference (ΔT) compared to the temperature of the liquefied natural gas, and heat exchange between the mixed refrigerant and the liquefied natural gas.

In the case of a single refrigerant, the temperature is constant or the temperature decreases while the phase change occurs, but when refrigerants having a boiling point difference of more than a set value are mixed, the temperature of the mixed refrigerant gradually increases while the phase change of the mixed refrigerant occurs in the evaporator 140. As it rises, a temperature gliding effect occurs at which the mixed refrigerant vaporizes.

When the phase change of the mixed refrigerant, the amount of temperature increase is 2 to 3°C or higher, preferably 10°C or higher, so that refrigerants having a large difference in boiling point are used, and the mixing ratio of the refrigerant having a low boiling point is at least a certain level (mixed refrigerant It is preferable to mix at least 5% by weight). Therefore, it is possible to implement a regasification system that satisfies the condition that the minimum temperature difference between natural gas and the mixed refrigerant is secured, and there is no need to install a trim heater at the rear end of the carburetor, and the thermal energy and latent heat of the mixed refrigerant are sufficiently utilized. Liquefied gas can be vaporized efficiently.

In addition, even when the temperature of the heat source is relatively low, such as seawater, efficient heat transfer to the liquefied gas is possible by using the latent heat of the mixed refrigerant, and the liquefied gas regasification and cold heat power generation system can be simplified and the operation efficiency can be increased. It is possible to increase safety compared to a system using a highly flammable heat transfer medium such as propane by comprising non-flammable refrigerants.

The conventional liquefied gas regasification system is operated by a vaporizer and a trim heater, and in order to operate the refrigerant in a liquid state in the trim heater, the regasifier must be operated at a high pressure to prevent vaporization of the refrigerant. There is a large difference in the operating pressure of the refrigerant between the and trim heaters.

However, according to the present embodiment, the pressure difference in the circulation loop of the heat medium circulation line 130 is small, and since the refrigerant circulates only a single heat exchange loop, it is only necessary to pressurize the pressure consumed in circulation and the head loss to recover the liquefied gas. Energy consumption for fire can be reduced.

As described above, according to the present embodiment, it is possible to maximize the effect of using latent heat of the mixed refrigerant to improve the liquefied gas vaporization performance, to reduce the amount of refrigerant used in the liquefied gas regasification and cold heat power generation system, and also, a trim heater is provided. There is no need to install, and the liquefied gas can be vaporized with a single vaporizer, thus simplifying the system configuration.

In addition, liquefied gas can be regasified by a single heat exchange process without going through two-stage heat exchange, and energy required for the pump and pipe size can be reduced by reducing the circulation flow rate of the mixed refrigerant. The cost can also be reduced.

In addition, according to an embodiment of the present invention, it is possible to implement a liquefied gas regasification system that efficiently utilizes the latent heat of the mixed refrigerant while changing the phase of the mixed refrigerant even in a low seawater design temperature range. In the case of using the evaporative mixed refrigerant, since the latent heat is much greater than the sensible heat, the flow rate of the circulating mixed refrigerant can be reduced, and thus the energy required for circulation of the mixed refrigerant is also reduced.

In order to maximize the temperature increase effect during the phase change of the mixed refrigerant as described above, the mixed refrigerant includes a first refrigerant having a boiling point of -40 to -10°C, and a second refrigerant having a boiling point of -60 to -90°C. Can include. A more preferable difference in boiling point between the first refrigerant and the second refrigerant is 50° C. or more.

In order to control the pressure of the mixed refrigerant below the design pressure of the evaporator 160 and at the same time obtain a temperature increase effect when the mixed refrigerant phase changes in the evaporator 160, the second refrigerant has a boiling point lower than that of the first refrigerant. The refrigerant may be mixed with the first refrigerant to have a weight ratio of 0.05 to 0.15 based on the weight of the mixed refrigerant.

The mixed refrigerant may be composed of refrigerants having a non-flammable property, an ozone depletion index of 0, and a global warming index of less than 2000. 3 is a diagram showing the safety class classification criteria for refrigerants. As shown in FIG. 8, the refrigerant is classified into safety grades according to toxicity and flammability.

In an embodiment, the refrigerants of the mixed refrigerant may be selected from refrigerants having a safety class of A1, except for refrigerants having a safety group of B1 to B3 or A2 to A3. That is, a mixed refrigerant can be formed in consideration of only refrigerants having a safety grade having low toxicity and low flammability. In addition, the refrigerants of the mixed refrigerant are preferably selected from eco-friendly refrigerants having an ozone depletion index of 0 and a global warming index of less than 2000 (more preferably less than 1500).

In an embodiment, the mixed refrigerant is tetrafluoroethane (1,1,1,2-tetrafluoroethane, R134a; CH ₂ FCF ₃ ) corresponding to the first refrigerant and carbon dioxide (R744; CO _{2) corresponding to the second refrigerant.} ), including at least two or more refrigerants. Two refrigerants (R134a, R744) are refrigerants classified as safety grades corresponding to A1, are non-toxic and non-flammable, and have an Ozone Depletion Potential (ODP) of 0. In addition, R744 refrigerant has a Global Warming Potential (GWP) of 1, and R134a refrigerant has a GWP of 1430, which is higher than R744 refrigerant, but has a lower value than the GWP standard suggested by various regulations and classification so that it satisfies the regulations. It is suitable for use.

Because R744 is more volatile than R134a, its boiling point is about 50°C or more. R134a has a boiling point of about -26℃, and R744 has a boiling point of about -78℃. Accordingly, when a mixed refrigerant in which two refrigerants R134a and R744 are mixed is used, a temperature gliding effect in which a temperature increases during a phase change due to a large difference in boiling point of the two refrigerants can be sufficiently obtained.

The mixed refrigerant may contain tetrafluoroethane (CH ₂ FCF ₃ , R134a) and carbon dioxide (CO ₂ , R744) in a weight ratio of 85 to 95% and 5 to 15% by weight, respectively. When the R744 refrigerant is contained in an amount of less than 5% by weight, it is difficult to obtain a temperature increase effect when the phase change of the mixed refrigerant due to the high boiling point difference between R744 and R134a.

Conversely, when the mixing ratio of the R744 refrigerant exceeds 15% by weight, the pressure of the mixed refrigerant in the evaporator 160 exceeds 20 barg due to the high content of R744 having high volatility, and withstands a high pressure of 20 barg or more. In order to be able to do so, there may be a problem in that the design thickness of the evaporator 160 must be increased.

9 is a graph showing temperature change characteristics according to the heat flow amount of the mixed refrigerant for each mixing ratio of the mixed refrigerant used in the liquefied gas regasification system of a ship according to an embodiment of the present invention. A mixed refrigerant mixed with CH ₂ FCF ₃ (R134a) and CO ₂ (R744) was used, and the temperature change characteristics of the mixed refrigerant while changing the weight ratio of R744 to 0.05, 0.1, and 0.15, the minimum between the mixed refrigerant and seawater (SW). The proximity temperature, the saturated vapor pressure of the mixed refrigerant in the evaporator, and the mixed refrigerant flow rate were measured.

Table 2 shows the minimum proximity temperature (minimum temperature between the mixed refrigerant and seawater) of the mixed refrigerant according to the weight ratio of _{CH 2} FCF ₃ (R134a) and CO _{2 (R744) constituting the mixed refrigerant, and the saturated vapor pressure of the mixed refrigerant (based on 50℃)} And changes in the flow rate of the mixed refrigerant. From Table 1, it can be seen that as the weight ratio of R744 increases, the saturated vapor pressure of the mixed refrigerant in the evaporator increases.

The more volatile of R134a and R744 is R744. The more R744 is mixed, the greater the temperature gliding effect during phase change of the mixed refrigerant, so that the refrigerant circulation flow rate decreases.However, the vapor pressure of the mixed refrigerant in the evaporator 140 increases, making a heat exchanger. May not satisfy the design pressure.

In the offshore platform or ship, there is a limitation that the system must be configured with a limited space compared to the onshore plant. On land, an open-rack vaporizer that vaporizes fluid using air or seawater can be used, but there are restrictions on installing and operating such a large-scale system on a ship. Accordingly, compact equipment such as a plate heat exchanger (PHE) and a printed circuit heat exchanger (PCHE) must be operated, and such equipment has limitations in manufacturing size and price.

In the evaporator 160 used in the circulation cycle of the mixed refrigerant, the performance, price, design pressure, etc. of the heat exchanger are determined according to the thickness of the plate, which is an internal component. In the refrigerant system, the system is operated by setting the system design pressure to the vapor saturation pressure at a specific temperature. Since R744 is more volatile than R134a, the design pressure increases as the mixing composition ratio of R744 increases.

Therefore, in order to satisfy the design pressure of the mixed refrigerant in consideration of the performance and price of the evaporator 160 used in the ship, it is preferable to control the mixing composition ratio of R744 to 15% by weight or less. Therefore, in order to obtain a temperature increase effect during phase change of the mixed refrigerant and to control the pressure of the mixed refrigerant below the design pressure, the mixing ratio of R744 is controlled so that 5 to 15% by weight of R744 is contained in the mixed refrigerant. It is desirable to do it.

When the evaporator is provided as a plate heat exchanger made of a 0.6mm thick tungsten plate to withstand the pressure of the mixed refrigerant (saturated vapor pressure) of 16 barg, the pressure of the mixed refrigerant in the evaporator (saturated vapor pressure) is 16 at an outside temperature of 50°. In order to satisfy the condition of barg or less, it is preferable that the mixing ratio of the second refrigerant R744 having a low boiling point among the mixed refrigerants is 10% by weight or less.

Table 3 shows the change in boiling point temperature and dew point temperature of the mixed refrigerant according to the pressure of the mixed refrigerant when the weight ratio of R134a and R744 is 0.95:0.05 and 0.85:0.15. When the ratio of R744 is high (when the weight ratio of R744 is 15%), the difference between the dew point temperature and the bubble point temperature of the mixed refrigerant increases, and the temperature increase effect increases when the mixed refrigerant phase changes. In addition, it becomes advantageous to use a mixed refrigerant within the limited temperature conditions of seawater and LNG.

When the ratio of R744 is low (when the weight ratio of R744 is 5%), the difference between the dew point temperature and the boiling point temperature of the mixed refrigerant decreases. When the weight ratio of R744 is less than 5%, the difference between the dew point temperature and the boiling point temperature of the mixed refrigerant at a vapor pressure of 10 to 20 barg decreases to less than about 10°C, resulting in a temperature increase effect when the phase change of the mixed refrigerant in the evaporator 140 May decrease. Therefore, it is desirable to keep R744 above 5% by weight.

10 is a graph illustrating a refrigerant characteristic curve showing the state of the heat medium according to the enthalpy and pressure of the heat medium.

6 and 10, the flow rate and pressure of the heat medium introduced into the expansion turbine 170 is such that the heat medium flowing into the expansion turbine 170 does not deviate from the gas-liquid mixing section in which the expansion turbine 170 can be operated normally. In addition, the heat medium discharged from the vaporizer 120 may be controlled to become a liquid. That is, when the heat medium introduced into the expansion turbine 170 is discharged, the pressure applied to the expansion turbine 170 may be limited so that it does not go beyond the operating gas-liquid mixing section.

It is to be understood that the above embodiments have been presented to aid understanding of the present invention, do not limit the scope of the present invention, and various deformable embodiments from this also fall within the scope of the present invention. The technical protection scope of the present invention should be determined by the technical idea of the claims, and the technical protection scope of the present invention is not limited to the literal description of the claims itself, but a scope that has substantially equal technical value. It should be understood that it extends to the invention of

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Claims (6)

A platform having an LNG storage tank for storing LNG and located on the sea;
A loading facility installed on the platform for bunkering when berthing other ships;
A liquefied gas regasification and cold heat power generation facility mounted on the platform; And
LNG bunkering platform including BOG transmission means for transmitting BOG generated in the process of supplying LNG to land. The method of claim 1,
The BOG transmission means
An LNG bunkering platform comprising a high pressure compressor for compressing and transmitting the BOG at high pressure. The method of claim 1,
The BOG transmission means
An LNG bunkering platform that compresses the BOG with a low pressure compressor and transmits it to land through recondensation in the regasification facility for cold and heat power generation. The method of claim 1,
A plurality of support columns vertically erected on the platform at intervals from each other; And
The LNG bunkering platform further comprises a jack-up device installed on the platform and the support pillar to raise the platform along the support pillar. The method of claim 1,
The loading facility is an LNG bunkering platform provided to be adjustable in height on the platform. The method of claim 1,
The liquefied gas regasification and cold heat power generation facility is installed on a liquefied gas transfer line for sending out from the storage tank to a demander on land,
A heating medium circulation line through which a heating medium for vaporizing the liquefied gas is circulated;
An evaporator installed in the heat medium circulation line and vaporizing the heat medium by heat exchange with a heat source;
A vaporizer installed in the heating medium circulation line and regasifying the liquefied gas of the liquefied gas transfer line by using thermal energy and latent heat of the vaporized heating medium;
An expansion turbine installed between the evaporator and the vaporizer in the heating medium circulation line and generating power by the power of the heating medium vaporized by the evaporator;
A first heat exchanger for heating the liquefied gas regasified by the vaporizer to a temperature required by the customer;
The first heat exchanger LNG bunkering platform receiving a portion of the heat medium vaporized by the evaporator through a first heat source supply line.

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