Pressure control system and liquefied carbon dioxide carrier having system

Abstract

A pressure control system according to a fifth embodiment of the present invention comprises: a liquefied carbon dioxide storage tank (110) for storing liquefied carbon dioxide; a pressure discharge unit (160) for preventing damage to the liquefied carbon dioxide storage tank (110) due to excessive pressure caused by boil-off gas inside the liquefied carbon dioxide storage tank (110); and a gas supply unit (190) for supplying, to an air lubrication system (ALS) or a ballast water treatment system (BWTS), the vaporized carbon dioxide having passed through the pressure discharge unit (160), and thus the boil-off gas is to be utilized in many ways in a ship.

Description

Liquefied carbon dioxide carrier equipped with pressure control system and dynamic system

[0001] The present invention relates to a pressure control system and a liquefied carbon dioxide carrier equipped with the system, and more particularly, to a pressure control system and a liquefied carbon dioxide carrier equipped with the system, which prevents blockage of an unloading pipe, re-liquefies boil-off gas (vaporized carbon dioxide) without a separate refrigerant, supplies liquefied carbon dioxide from a liquefied carbon dioxide storage tank during initial operation of the re-liquefaction unit to maintain the performance of the re-liquefaction unit, allows for various uses of boil-off gas (vaporized carbon dioxide) within the ship, and forcibly vaporizes liquefied carbon dioxide stored in a liquefied carbon dioxide storage tank to supplement a shortage of vaporized carbon dioxide in a gas supply unit.

[0002] As is well known, efforts are underway to reduce carbon dioxide (CO2) emissions to achieve carbon neutrality, and this requires direct reduction through carbon capture, utilization, and storage (CCUS). Carbon capture, utilization, and storage (CCUS) technology involves capturing carbon dioxide emitted from industrial facilities and storing it underground (Carbon Capture Storage, CCS) as well as utilizing carbon dioxide (Carbon Capture Utilization, CCU) to convert it into valuable resources with high added value. A liquefied carbon dioxide (CO2) carrier, one of these CCUS technologies, is a vessel required to separate and recover carbon dioxide emitted on land, liquefy it under conditions of approximately -55°C and 5 atm, and transport the liquefied carbon dioxide to marine isolation areas. These liquefied carbon dioxide carriers are equipped with liquefied carbon dioxide storage tanks to store the liquefied carbon dioxide.

[0003] When transporting liquefied carbon dioxide using a liquefied carbon dioxide carrier, the pressure drop within the liquefied carbon dioxide storage tank can cause the liquefied carbon dioxide to solidify, generating solid carbon dioxide. Furthermore, when unloading the liquefied carbon dioxide, the pressure drop within the liquefied carbon dioxide storage tank and / or the transport piping can cause the carbon dioxide to solidify, generating solid carbon dioxide. This solid carbon dioxide can clog the transport piping, damaging both the transport piping and the liquefied carbon dioxide storage tank.

[0004] Specifically, Boyle's law states that at a constant volume, P(pressure) / T(temperature) remains constant. That is, when the pressure inside a tank or pipe drops, the temperature also drops, so the temperature drop caused by the pressure drop causes the liquefied carbon dioxide to solidify.

[0005] Additionally, in the event of an abnormal condition, such as a pressure rise within a liquefied carbon dioxide storage tank, a pressure relief valve (PRV) installed on the safety pipe that discharges vaporized carbon dioxide to the outside is activated to relieve the condition. However, in this case, the pressure and temperature within the safety pipe simultaneously drop, generating solid carbon dioxide that is then discharged to the outside, potentially causing secondary damage.

[0006] Accordingly, a technology is required that can prevent dry ice from being generated during unloading and blocking the pipes, re-liquefy the evaporated gas (vaporized carbon dioxide) exhausted through the PRV and recycle it as a heat exchange refrigerant, and utilize the evaporated gas (vaporized carbon dioxide) in various ways on board the ship.

[0007] The technical problem to be achieved by the idea of ​​the present invention is to provide a pressure control system and a liquefied carbon dioxide carrier equipped with the system, which prevents blockage of an unloading pipe, re-liquefies boil-off gas (vaporized carbon dioxide) without a separate refrigerant, supplies liquefied carbon dioxide from a liquefied carbon dioxide storage tank during initial operation of the re-liquefaction unit to maintain the performance of the re-liquefaction unit, utilizes boil-off gas (vaporized carbon dioxide) in various ways within the ship, and forcibly vaporizes liquefied carbon dioxide stored in a liquefied carbon dioxide storage tank to supplement the shortage of vaporized carbon dioxide in the gas supply unit.

[0008] In order to achieve the above-described object, a first embodiment of the present invention provides a pressure control system including: a liquefied carbon dioxide storage tank for storing liquefied carbon dioxide; an unloading pipe for unloading liquefied carbon dioxide from the liquefied carbon dioxide storage tank; a pressure maintaining unit for preventing a temperature drop due to a pressure drop inside the liquefied carbon dioxide storage tank, thereby preventing the generation of solid carbon dioxide; and a first gas supply unit branched from the pressure maintaining unit for supplying vaporized carbon dioxide forcibly vaporized by the pressure maintaining unit to an unloading pipe of the unloading pipe to maintain the internal pressure of the unloading pipe, thereby removing solid carbon dioxide.

[0009] Here, the pressure maintenance unit may be composed of a circulation pipe connected from one side of the liquefied carbon dioxide storage tank to the other side, a PBU (Pressure Buildup Unit) installed in the circulation pipe to forcibly vaporize the liquefied carbon dioxide in the liquefied carbon dioxide storage tank, and a control valve that adjusts the flow rate of the forcibly vaporized vaporized carbon dioxide through the circulation pipe and returns it to the liquefied carbon dioxide storage tank.

[0010] At this time, the pressure maintenance unit may further include an injection nozzle that injects the forcibly vaporized vaporized carbon dioxide into the interior of the liquefied carbon dioxide storage tank.

[0011] In addition, a pressure control valve for controlling the pressure of liquefied carbon dioxide supplied to the PBU through the circulation pipe may be further included.

[0012] Additionally, the PBU may consist of a vaporizer or a heater.

[0013] In addition, the first gas supply unit may be configured with a branch pipe branched from the circulation pipe and connected to the unloading pipe, a three-way valve controlling the supply of the forcedly vaporized carbon dioxide from the circulation pipe to the branch pipe, and a first globe valve installed in the branch pipe to control the flow rate of the forcedly vaporized carbon dioxide.

[0014] Here, a first pressure sensor and a first temperature sensor are disposed inside the liquefied carbon dioxide storage tank to measure pressure and temperature, and a second pressure sensor and a second temperature sensor are disposed in the unloading pipe to measure pressure and temperature. The first measurement value by the first pressure sensor and the first temperature sensor, and the second measurement value by the second pressure sensor and the second temperature sensor are fed back to control the three-way valve, thereby preventing the generation of solid carbon dioxide inside the liquefied carbon dioxide storage tank or removing solid carbon dioxide inside the unloading pipe.

[0015] In addition, the unloading pipe section may be composed of the unloading pipe connected to the branch pipe, a second globe valve installed in the unloading pipe to control the flow rate of liquefied carbon dioxide unloaded from the liquefied carbon dioxide storage tank, a first unloading pipe and a second unloading pipe branched from the unloading pipe, a first filter installed in the first unloading pipe to filter solid carbon dioxide, a third globe valve formed at the rear end of the first filter to control the flow rate of liquefied carbon dioxide, a second filter installed in the second unloading pipe to filter solid carbon dioxide, and a fourth globe valve formed at the rear end of the second filter to control the flow rate of liquefied carbon dioxide.

[0016] Here, in the initial stage of unloading liquefied carbon dioxide through the unloading pipe, the third globe valve can be opened and the fourth globe valve can be closed.

[0017] At this time, a first filter sensor installed in the first filter to detect the state of the first filter is further included, and when the measured value by the first filter sensor exceeds a preset standard value of solid carbon dioxide, the third globe valve can be closed and the fourth globe valve can be opened.

[0018] Additionally, the first filter and the second filter may each include a heater.

[0019] In addition, the system further includes a second gas supply unit that supplies vaporized carbon dioxide, which is an evaporated gas generated from the liquefied carbon dioxide storage tank, to the unloading pipe, and, based on the second measurement values ​​by the second pressure sensor and the second temperature sensor, the vaporized carbon dioxide forcibly vaporized by the first gas supply unit or the vaporized carbon dioxide by the second gas supply unit can be supplied to the unloading pipe.

[0020] Meanwhile, a second embodiment of the present invention provides a pressure control system including: a liquefied carbon dioxide storage tank for storing liquefied carbon dioxide; an unloading pipe for unloading liquefied carbon dioxide from the liquefied carbon dioxide storage tank; a pressure relief unit for preventing damage to the liquefied carbon dioxide storage tank due to excessive pressure caused by evaporated gas inside the liquefied carbon dioxide storage tank; and a fourth gas supply unit for supplying vaporized carbon dioxide passing through the pressure relief unit to an unloading pipe of the unloading pipe to maintain the internal pressure of the unloading pipe and remove solid carbon dioxide.

[0021] Here, the pressure relief unit may include a safety pipe connected to the liquefied carbon dioxide storage tank, and a PRV (Pressure Relief Valve) installed in the safety pipe to discharge vaporized carbon dioxide, which is an evaporation gas, from the liquefied carbon dioxide storage tank.

[0022] At this time, the safety pipe and the PRV may each be configured as a pair.

[0023] In addition, the fourth gas supply unit may include a knockout drum tank coupled to the rear end of the safety pipe to capture vaporized carbon dioxide discharged through the PRV, a venting pipe connecting the safety pipe and the knockout drum tank, and a fifth globe valve formed at the rear end of the knockout drum tank to control the flow rate of vaporized carbon dioxide to the unloading pipe.

[0024] Here, the PRV may be configured in a plurality of units, and may further include one or more connecting pipes that interconnect the plurality of PRVs and are connected to the venting pipe, and an internal observation unit installed on the connecting pipe to visually identify whether solid carbon dioxide is generated inside the connecting pipe.

[0025] Additionally, a recovery pipe may be further formed to supply vaporized carbon dioxide from the knockout drum tank to the liquefied carbon dioxide storage tank.

[0026] In addition, the system further includes a first pressure sensor and a first temperature sensor disposed inside the liquefied carbon dioxide storage tank to measure pressure and temperature, and a second pressure sensor and a second temperature sensor disposed in the unloading pipe to measure pressure and temperature, and by feeding back the first measurement value by the first pressure sensor and the first temperature sensor and the second measurement value by the second pressure sensor and the second temperature sensor, the generation of solid carbon dioxide inside the liquefied carbon dioxide storage tank can be prevented, or the solid carbon dioxide inside the unloading pipe can be removed.

[0027] In addition, the unloading pipe section may be configured with a second globe valve installed in the unloading pipe to control the flow rate of liquefied carbon dioxide unloaded from the liquefied carbon dioxide storage tank, a first unloading pipe and a second unloading pipe branched from the unloading pipe, a first filter installed in the first unloading pipe to filter solid carbon dioxide, a third globe valve formed at the rear end of the first filter to control the flow rate of liquefied carbon dioxide, a second filter installed in the second unloading pipe to filter solid carbon dioxide, and a fourth globe valve formed at the rear end of the second filter to control the flow rate of liquefied carbon dioxide.

[0028] Here, in the initial stage of unloading liquefied carbon dioxide through the unloading pipe, the third globe valve can be opened and the fourth globe valve can be closed.

[0029] At this time, a first filter sensor installed in the first filter to detect the state of the first filter is further included, and when the measured value by the first filter sensor exceeds a preset standard value of solid carbon dioxide, the third globe valve can be closed and the fourth globe valve can be opened.

[0030] Additionally, the first filter and the second filter may each include a heater.

[0031] In addition, the third gas supply unit is further included to supply the vaporized carbon dioxide produced by forcibly vaporizing the liquefied carbon dioxide supplied from the liquefied carbon dioxide storage tank to the unloading pipe, and the vaporized carbon dioxide produced by the fourth gas supply unit or the vaporized carbon dioxide forcibly vaporized by the third gas supply unit can be supplied to the unloading pipe according to the second measurement value by the second pressure sensor and the second temperature sensor.

[0032] Meanwhile, a third embodiment of the present invention provides a pressure control system including: a liquefied carbon dioxide storage tank for storing liquefied carbon dioxide; a pressure relief unit for preventing damage to the liquefied carbon dioxide storage tank due to excessive pressure caused by boil-off gas inside the liquefied carbon dioxide storage tank; and a re-liquefaction unit for storing vaporized carbon dioxide, which is boil-off gas discharged through the pressure relief unit, and re-liquefying the vaporized carbon dioxide by a self-heat exchange method to return it to the liquefied carbon dioxide storage tank.

[0033] Here, the pressure relief unit may include a safety pipe connected to the liquefied carbon dioxide storage tank, and a PRV (Pressure Relief Valve) installed in the safety pipe to discharge vaporized carbon dioxide from the liquefied carbon dioxide storage tank.

[0034] At this time, the safety pipe and the PRV may each be configured as a pair.

[0035] In addition, the re-liquefaction unit may be configured with a buffer tank coupled to the rear end of the safety pipe and storing the vaporized carbon dioxide, which is the vaporized gas discharged through the pressure relief unit, a venting pipe connecting the safety pipe and the buffer tank, a first compressor for compressing the vaporized carbon dioxide transferred from the buffer tank, a condenser coupled to the rear end of the first compressor and condensing the vaporized carbon dioxide, a second compressor coupled to the rear end of the condenser and compressing the vaporized carbon dioxide, a Joule-Thomson valve coupled to the rear end of the second compressor and expanding the vaporized carbon dioxide, a gas-liquid separator coupled to the rear end of the Joule-Thomson valve and separating the vaporized carbon dioxide and liquid carbon dioxide, a first recovery pipe for recovering the vaporized carbon dioxide separated by the gas-liquid separator to the condenser, and an injection nozzle for injecting the liquefied carbon dioxide separated by the gas-liquid separator to the condenser to condense the vaporized carbon dioxide.

[0036] Here, the buffer tank may be an IMO type C tank.

[0037] Additionally, some of the liquefied carbon dioxide condensed and liquefied by the condenser can be recovered into the liquefied carbon dioxide storage tank.

[0038] Additionally, some of the liquefied carbon dioxide separated by the gas-liquid separator can be recovered into the liquefied carbon dioxide storage tank.

[0039] Meanwhile, a fourth embodiment of the present invention provides a pressure control system including: a liquefied carbon dioxide storage tank for storing liquefied carbon dioxide; a pressure relief unit for preventing damage to the liquefied carbon dioxide storage tank due to excessive pressure caused by boil-off gas inside the liquefied carbon dioxide storage tank; a re-liquefaction unit for storing vaporized carbon dioxide, which is boil-off gas discharged through the pressure relief unit, and re-liquefying the vaporized carbon dioxide by a self-heat exchange method and returning it to the liquefied carbon dioxide storage tank; and a re-liquefaction supply unit for supplying liquefied carbon dioxide stored in the liquefied carbon dioxide storage tank to the re-liquefaction unit during initial operation of the re-liquefaction unit.

[0040] Here, the re-liquefaction supply unit may be a pressure maintenance unit that prevents the generation of solid carbon dioxide by preventing a temperature drop due to a pressure drop inside the liquefied carbon dioxide storage tank.

[0041] At this time, the pressure maintenance unit may be composed of a circulation pipe connected from one side of the liquefied carbon dioxide storage tank to the other side, a PBU (Pressure Buildup Unit) installed in the circulation pipe to forcibly vaporize the liquefied carbon dioxide in the liquefied carbon dioxide storage tank, and a control valve that adjusts the flow rate of the forcibly vaporized carbon dioxide through the circulation pipe and returns it to the liquefied carbon dioxide storage tank.

[0042] In addition, the re-liquefaction supply unit may be configured with an initial operation pipe branched from the circulation pipe before the liquefied carbon dioxide is supplied to the PBU and connected to the condenser of the re-liquefaction unit, and a pump that supplies the liquefied carbon dioxide to the condenser through the initial operation pipe.

[0043] In addition, the pressure relief unit may include a safety pipe connected to the liquefied carbon dioxide storage tank, and a PRV (Pressure Relief Valve) installed in the safety pipe to discharge vaporized carbon dioxide, which is an evaporation gas, from the liquefied carbon dioxide storage tank.

[0044] Here, the safety pipe and the PRV may each be configured as a pair.

[0045] In addition, the re-liquefaction unit may be configured with a buffer tank coupled to the rear end of the safety pipe and storing the vaporized carbon dioxide, which is the vaporized gas discharged through the pressure relief unit, a venting pipe connecting the safety pipe and the buffer tank, a first compressor for compressing the vaporized carbon dioxide transferred from the buffer tank, a condenser coupled to the rear end of the first compressor and condensing the vaporized carbon dioxide, a second compressor coupled to the rear end of the condenser and compressing the vaporized carbon dioxide, a Joule-Thomson valve coupled to the rear end of the second compressor and expanding the vaporized carbon dioxide, a gas-liquid separator coupled to the rear end of the Joule-Thomson valve and separating the vaporized carbon dioxide and liquid carbon dioxide, a first recovery pipe for recovering the vaporized carbon dioxide separated by the gas-liquid separator to the condenser, and an injection nozzle for injecting the liquefied carbon dioxide separated by the gas-liquid separator to the condenser to condense the vaporized carbon dioxide.

[0046] Here, the buffer tank may be an IMO type C tank.

[0047] Additionally, some of the liquefied carbon dioxide condensed and liquefied by the condenser can be recovered into the liquefied carbon dioxide storage tank.

[0048] Additionally, some of the liquefied carbon dioxide separated by the gas-liquid separator can be recovered into the liquefied carbon dioxide storage tank.

[0049] Meanwhile, a fifth embodiment of the present invention provides a pressure control system including: a liquefied carbon dioxide storage tank for storing liquefied carbon dioxide; a pressure relief unit for preventing damage to the liquefied carbon dioxide storage tank due to excessive pressure caused by evaporated gas inside the liquefied carbon dioxide storage tank; and a gas supply unit for supplying evaporated carbon dioxide passing through the pressure relief unit to an ALS (Air Lubrication System) or a BWTS (Ballast Water Treatment System).

[0050] Here, the gas supply unit can compress the vaporized carbon dioxide, which is the vaporized gas discharged through the pressure discharge unit through the ALS, dissolve it in seawater, and spray it onto the ship's bottom.

[0051] In addition, the gas supply unit can dissolve the vaporized carbon dioxide, which is the vaporized gas discharged through the pressure discharge unit through the BWTS, into the equilibrium water to lower the pH of the equilibrium water.

[0052] In addition, the pressure relief unit may include a safety pipe connected to the liquefied carbon dioxide storage tank, and a PRV (Pressure Relief Valve) installed in the safety pipe to discharge vaporized carbon dioxide from the liquefied carbon dioxide storage tank.

[0053] Here, the safety pipe and the PRV may each be configured as a pair.

[0054] In addition, the gas supply unit may be configured with a buffer tank that is connected to the rear end of the safety pipe and stores the vaporized carbon dioxide, which is an evaporated gas discharged through the pressure relief unit, a venting pipe that connects the safety pipe and the buffer tank, a sixth globe valve that is formed at the rear end of the buffer tank and supplies the vaporized carbon dioxide to the ALS, and a seventh globe valve that is formed at the rear end of the buffer tank and supplies the vaporized carbon dioxide to the BWTS.

[0055] Here, the gas supply unit may further include an eighth globe valve for supplying vaporized carbon dioxide to the liquefied carbon dioxide storage tank.

[0056] Meanwhile, a sixth embodiment of the present invention provides a pressure control system including: a liquefied carbon dioxide storage tank for storing liquefied carbon dioxide; a pressure relief unit for preventing damage to the liquefied carbon dioxide storage tank due to excessive pressure caused by evaporated gas inside the liquefied carbon dioxide storage tank; a gas supply unit for supplying vaporized carbon dioxide passing through the pressure relief unit to an ALS (Air Lubrication System) or a BWTS (Ballast Water Treatment System); and a gas supplement unit for supplementing a shortage of vaporized carbon dioxide by the gas supply unit.

[0057] Here, the pressure relief unit may include a safety pipe connected to the liquefied carbon dioxide storage tank, and a PRV (Pressure Relief Valve) installed in the safety pipe to discharge vaporized carbon dioxide from the liquefied carbon dioxide storage tank.

[0058] At this time, the safety pipe and the PRV may each be configured as a pair.

[0059] In addition, the gas supply unit may be configured with a buffer tank that is connected to the rear end of the safety pipe and stores the vaporized carbon dioxide, which is an evaporated gas discharged through the pressure relief unit, a venting pipe that connects the safety pipe and the buffer tank, a sixth globe valve that controls the flow rate of the vaporized carbon dioxide to the ALS, a seventh globe valve that controls the flow rate of the vaporized carbon dioxide to the BWTS, and an eighth globe valve that controls the flow rate of the vaporized carbon dioxide to the liquefied carbon dioxide storage tank.

[0060] Here, the buffer tank may be an IMO type C tank.

[0061] In addition, the gas replenishment unit may be configured with a pump that pumps liquefied carbon dioxide from the liquefied carbon dioxide storage tank, and an evaporator that forcibly vaporizes the liquefied carbon dioxide supplied by the pump to generate forcibly vaporized vaporized carbon dioxide.

[0062] Here, the buffer tank includes a pressure sensor that measures the pressure of the vaporized carbon dioxide, and the gas replenishment unit can supply the shortage of the vaporized carbon dioxide to the buffer tank based on the measured value by the pressure sensor.

[0063] In addition, a branch pipe may be further included that is connected to the rear end of the evaporator and supplies the forcibly vaporized vaporized carbon dioxide by diverting it into the inside of the liquefied carbon dioxide storage tank to maintain the internal pressure of the liquefied carbon dioxide storage tank.

[0064] Meanwhile, the present invention additionally provides a liquefied carbon dioxide carrier equipped with the aforementioned pressure control system.

[0065] According to the present invention, by generating vaporized carbon dioxide through PBU and utilizing it to maintain the internal pressure of an unloading pipe, there is an effect of preventing a pipe blockage phenomenon caused by solidification of liquefied carbon dioxide due to a temperature drop caused by a pressure drop inside a liquefied carbon dioxide storage tank and / or in an unloading pipe when unloading liquefied carbon dioxide.

[0066] In addition, by capturing the evaporated gas exhausted from the PRV and generating vaporized carbon dioxide to use for maintaining the internal pressure of the unloading pipe, there is an effect of preventing the pipe blockage phenomenon caused by the solidification of the liquefied carbon dioxide due to a temperature drop caused by a pressure drop inside the liquefied carbon dioxide storage tank and / or in the unloading pipe when unloading the liquefied carbon dioxide.

[0067] In addition, it has the effect of storing the evaporated gas and re-liquefying it through self-heat exchange without a separate refrigerant or expensive heat exchange equipment.

[0068] In addition, during the initial operation of the re-liquefaction unit, the performance of the re-liquefaction unit is maintained by supplying liquefied carbon dioxide from the liquefied carbon dioxide storage tank, and there is an effect of storing the evaporated gas and re-liquefying it by self-heat exchange without a separate refrigerant or expensive heat exchange equipment.

[0069] In addition, it has the effect of being able to store the evaporated gas vented through the PRV and utilize it in various ways within the ship to increase operating efficiency, implement anti-fouling performance, kill microorganisms in ballast water, and maintain the internal pressure of the tank.

[0070] Furthermore, it has the effect of forcibly vaporizing the liquefied carbon dioxide stored in the liquefied carbon dioxide storage tank to supplement the shortage of vaporized carbon dioxide in the gas supply section, storing the vaporized gas vented through the PRV and utilizing it in various ways within the ship to increase operating efficiency, implement anti-fouling performance, kill microorganisms in ballast water, and utilize it to maintain the internal pressure of the tank.

[0071] Figure 1 illustrates a pressure control system according to a first embodiment of the present invention.

[0072] Figure 2 illustrates a pressure control system according to a second embodiment of the present invention.

[0073] Figure 3 illustrates a pressure control system according to a third embodiment of the present invention.

[0074] Figure 4 illustrates a pressure control system according to a fourth embodiment of the present invention.

[0075] Figure 5 illustrates a pressure control system according to a fifth embodiment of the present invention.

[0076] Figure 6 illustrates a pressure control system according to a sixth embodiment of the present invention.

[0077] Figure 7 illustrates the PVT diagram of carbon dioxide.

[0078] Hereinafter, an embodiment of the present invention having the above-described features will be described in more detail with reference to the attached drawings.

[0079] The pressure control system according to the first embodiment of the present invention includes a liquefied carbon dioxide storage tank (110) for storing liquefied carbon dioxide, an unloading pipe (120) for unloading liquefied carbon dioxide from the liquefied carbon dioxide storage tank (110), a pressure maintaining unit (130) for preventing a temperature drop due to a pressure drop inside the liquefied carbon dioxide storage tank (110) and thus preventing the generation of solid carbon dioxide, and a first gas supply unit (140) branching from the pressure maintaining unit (130) and supplying vaporized carbon dioxide forcibly vaporized by the pressure maintaining unit (130) to an unloading pipe (121) of the unloading pipe (120) to maintain the internal pressure of the unloading pipe (121) and remove solid carbon dioxide, thereby preventing clogging of the unloading pipe (121).

[0080] Hereinafter, with reference to FIG. 1, the pressure control system of the above-described configuration will be described in detail as follows.

[0081] First, a liquefied carbon dioxide storage tank (110) is installed on a liquefied carbon dioxide carrier to store and transport liquefied carbon dioxide supplied through a bunkering line (111).

[0082] Here, the liquefied carbon dioxide storage tank (110) may be an insulated tank in which liquefied carbon dioxide is stored, and may be an IMO type C storage tank. The IMO type C has an independent pressure vessel form and can be easily installed on the hull.

[0083] The liquefied carbon dioxide may be liquefied carbon dioxide captured by a carbon capture system (CCS) on land or at sea, or liquefied carbon dioxide captured by an onboard carbon dioxide capture system (not shown) from the ship's engine.

[0084] Additionally, the liquefied carbon dioxide storage tank (110) may be equipped with a level sensor (LT) for measuring the level of liquefied carbon dioxide, a temperature transmitter (TT) for measuring temperature, and a pressure transmitter (PT) for measuring pressure.

[0085] Referring to FIG. 7, the liquefied carbon dioxide storage tank (110) can store liquefied carbon dioxide by maintaining the inside thereof at a temperature of -30°C to -55°C and a pressure of 5 to 19 bar, preferably at a temperature of -45°C to -55°C and a pressure of 5.5 to 7.5 bar, and the tank control system (not shown) controls the temperature, pressure, etc. of the liquefied carbon dioxide inside the liquefied carbon dioxide storage tank (110) to store the liquefied carbon dioxide normally.

[0086] In addition, a plurality of bunkering lines (111) may be provided, and some of the plurality may be connected to the upper part of the liquid carbon dioxide storage tank (110) and configured with one end as a spray nozzle to be used as a bunkering line for cool-down.

[0087] Next, the unloading pipe (120) filters the solid carbon dioxide and unloads the liquefied carbon dioxide from the liquefied carbon dioxide storage tank (110).

[0088] Specifically, referring to FIG. 1, the unloading pipe section (120) includes an unloading pipe (121) connected to a branch pipe (141), a second globe valve (122) installed in the unloading pipe (121) to control the flow rate of liquefied carbon dioxide, a first unloading pipe (121a) and a second unloading pipe (121b) branched from the unloading pipe (121), a first filter (123) installed in the first unloading pipe (121a) to filter solid carbon dioxide, a third globe valve (124) formed at the rear end of the first filter (123) to control the flow rate of liquefied carbon dioxide, a second filter (125) installed in the second unloading pipe (121b) to filter solid carbon dioxide, and a third globe valve (124) formed at the rear end of the second filter (125) to control the flow rate of liquefied carbon dioxide. It can be composed of a fourth globe valve (126).

[0089] Here, in the initial stage of unloading liquefied carbon dioxide through the unloading pipe (121), the third globe valve (124) can be opened and the fourth globe valve (126) can be closed.

[0090] In addition, a first filter sensor (not shown) installed in the first filter (123) to detect the state of the first filter (123) is further included, and when the measurement value by the first filter sensor exceeds a preset reference value of solid carbon dioxide (for example, this may be a case where the amount of solid carbon dioxide filtered by the first filter (123) exceeds the reference amount, but is not limited thereto, and the reference value may be determined by considering the type of measurement value such as pressure, weight, volume, etc., and the same applies hereinafter), the third globe valve (124) may be closed and the fourth globe valve (126) may be opened, and in addition, the first filter (123) and the second filter (125) may each include a heater to melt the solid carbon dioxide.

[0091] For example, if the unloading of liquefied carbon dioxide continues for a long time, solid carbon dioxide accumulates in the first filter (123), and at this time, if the first filter sensor detects that the solid carbon dioxide exceeds the standard, the third globe valve (124) can be locked and the fourth globe valve (126) can be opened to continuously unload the liquefied carbon dioxide through the second unloading pipe (121b).

[0092] Next, the pressure maintenance unit (130) prevents the temperature drop due to the pressure drop inside the liquefied carbon dioxide storage tank (110) to prevent the generation of solid carbon dioxide.

[0093] Specifically, the pressure maintenance unit (130) may be composed of a circulation pipe (131) connected from one side to the other side of the liquefied carbon dioxide storage tank (110), a PBU (Pressure Buildup Unit) (132) installed in the circulation pipe (131) to monitor the internal pressure of the liquefied carbon dioxide storage tank (110) and forcibly vaporize the liquefied carbon dioxide, and a control valve (134) to control the flow rate of the vaporized carbon dioxide forcibly vaporized through the circulation pipe (131) and return it to the liquefied carbon dioxide storage tank (110).

[0094] Here, the vaporized carbon dioxide is returned to the liquefied carbon dioxide storage tank (110) through the circulation pipe (131) to maintain the internal pressure of the liquefied carbon dioxide storage tank (110) at a certain level, and the PBU (132) can forcibly vaporize the liquefied carbon dioxide to generate vaporized carbon dioxide, and the forcibly vaporized vaporized carbon dioxide can be returned to the liquefied carbon dioxide storage tank (110), and the PBU (132) can be configured as a vaporizer or a heater.

[0095] Through such a PBU (132), when transporting a liquefied carbon dioxide storage tank (110) and / or unloading liquefied carbon dioxide from a liquefied carbon dioxide storage tank (110), it can be operated to prevent the generation of solid carbon dioxide and minimize pipe blockage.

[0096] In addition, the pressure maintenance unit (130) may further include an injection nozzle (not shown) that injects forcibly vaporized carbon dioxide into the interior of the liquefied carbon dioxide storage tank (110), thereby controlling the internal pressure of the liquefied carbon dioxide storage tank (110) within an allowable pressure range, thereby preventing the generation of solid carbon dioxide due to a temperature drop caused by a pressure drop inside the liquefied carbon dioxide storage tank (110), thereby preventing damage to the liquefied carbon dioxide storage tank (110), and may further include a pressure control valve (133) that controls the pressure of the liquefied carbon dioxide supplied to the PBU (132) through the circulation pipe (131).

[0097] Next, the first gas supply unit (140) branches off from the pressure maintenance unit (130) and supplies the vaporized carbon dioxide forcibly vaporized by the pressure maintenance unit (130) to the unloading pipe (121) of the unloading pipe unit (120) to maintain the internal pressure of the unloading pipe (121) and remove solid carbon dioxide.

[0098] Specifically, the first gas supply unit (140) may be composed of a branch pipe (141) branched from the circulation pipe (131) and connected to the unloading pipe (121), a three-way valve (142) that controls the supply of forcedly vaporized carbon dioxide from the circulation pipe (131) to the branch pipe (141), and a first globe valve (143) that is installed in the branch pipe (141) and controls the flow rate of the forcedly vaporized carbon dioxide.

[0099] Meanwhile, a first pressure sensor (PT) and a first temperature sensor (TT) disposed inside the liquefied carbon dioxide storage tank (110) for measuring pressure and temperature, and a second pressure sensor (P) and a second temperature sensor (T) disposed in the unloading pipe (121) for measuring pressure and temperature are further included, and the first measurement value by the first pressure sensor (PT) and the first temperature sensor (TT) and the second measurement value by the second pressure sensor (P) and the second temperature sensor (T) are fed back to control the three-way valve (142), thereby preventing the generation of solid carbon dioxide inside the liquefied carbon dioxide storage tank (110) or removing solid carbon dioxide inside the unloading pipe (121).

[0100] Meanwhile, a second gas supply unit (150) is further included to supply vaporized carbon dioxide, which is boil-off gas (BOG) generated from a liquefied carbon dioxide storage tank (110), to an unloading pipe (121), and, depending on the second measurement values ​​by the second pressure sensor (P) and the second temperature sensor (T), the vaporized carbon dioxide can be selectively supplied to the unloading pipe (121) by the first gas supply unit (140) or the second gas supply unit (150).

[0101] Meanwhile, as another example, a liquefied carbon dioxide carrier equipped with the pressure control system listed above is provided.

[0102] Accordingly, by configuring a liquefied carbon dioxide carrier equipped with the pressure control system and the system as described above, by generating vaporized carbon dioxide through the PBU and utilizing it to maintain the internal pressure of the unloading pipe, it is possible to prevent the phenomenon of pipe blockage caused by solidification of the liquefied carbon dioxide due to a temperature drop caused by a pressure drop inside the liquefied carbon dioxide storage tank and / or in the unloading pipe when unloading the liquefied carbon dioxide.

[0103] The pressure control system according to the second embodiment of the present invention includes a liquefied carbon dioxide storage tank (110) for storing liquefied carbon dioxide, an unloading pipe (120) for unloading liquefied carbon dioxide from the liquefied carbon dioxide storage tank (110), a pressure discharge unit (160) for preventing damage to the liquefied carbon dioxide storage tank (110) due to excessive pressure caused by evaporated gas inside the liquefied carbon dioxide storage tank (110), and a fourth gas supply unit (170) for supplying vaporized carbon dioxide passing through the pressure discharge unit (160) to an unloading pipe (121) of the unloading pipe unit (120) to maintain the internal pressure of the unloading pipe (121) and remove solid carbon dioxide, thereby preventing clogging of the unloading pipe (121).

[0104] Hereinafter, with reference to FIG. 2, the pressure control system of the above-described configuration will be described in detail as follows.

[0105] First, a liquefied carbon dioxide storage tank (110) is installed on a liquefied carbon dioxide carrier to store and transport liquefied carbon dioxide supplied through a bunkering line (111).

[0106] Here, the liquefied carbon dioxide storage tank (110) may be an insulated tank in which liquefied carbon dioxide is stored, and may be an IMO type C storage tank. The IMO type C has an independent pressure vessel form and can be easily installed on the hull.

[0107] The liquefied carbon dioxide may be liquefied carbon dioxide captured by a carbon capture system (CCS) on land or at sea, or liquefied carbon dioxide captured by an onboard carbon dioxide capture system (not shown) from the ship's engine.

[0108] Additionally, the liquefied carbon dioxide storage tank (110) may be equipped with a level sensor (LT) for measuring the level of liquefied carbon dioxide, a temperature transmitter (TT) for measuring temperature, and a pressure transmitter (PT) for measuring pressure.

[0109] Referring to FIG. 7, the liquefied carbon dioxide storage tank (110) can store liquefied carbon dioxide by maintaining the inside thereof at a temperature of -30°C to -55°C and a pressure of 5 to 19 bar, preferably at a temperature of -45°C to -55°C and a pressure of 5.5 to 7.5 bar, and the tank control system (not shown) controls the temperature, pressure, etc. of the liquefied carbon dioxide inside the liquefied carbon dioxide storage tank (110) to store the liquefied carbon dioxide normally.

[0110] In addition, a plurality of bunkering lines (111) may be provided, and some of the plurality may be connected to the upper part of the liquid carbon dioxide storage tank (110) and configured with one end as a spray nozzle to be used as a bunkering line for cool-down.

[0111] Next, the unloading pipe (120) filters the solid carbon dioxide and unloads the liquefied carbon dioxide from the liquefied carbon dioxide storage tank (110).

[0112] Specifically, referring to FIG. 2, the unloading pipe section (120) includes an unloading pipe (121) connected to a branch pipe (141), a second globe valve (122) installed in the unloading pipe (121) to control the flow rate of liquefied carbon dioxide unloaded from the liquefied carbon dioxide storage tank (110), a first unloading pipe (121a) and a second unloading pipe (121b) branched from the unloading pipe (121), a first filter (123) installed in the first unloading pipe (121a) to filter solid carbon dioxide, a third globe valve (124) formed at the rear end of the first filter (123) to control the flow rate of liquefied carbon dioxide, a second filter (125) installed in the second unloading pipe (121b) to filter solid carbon dioxide, and a second globe valve (124) formed at the rear end of the second filter (125) to filter solid carbon dioxide. It can be configured with a fourth globe valve (126) that controls the flow rate of carbon dioxide.

[0113] Here, in the initial stage of unloading liquefied carbon dioxide through the unloading pipe (121), the third globe valve (124) can be opened and the fourth globe valve (126) can be closed.

[0114] In addition, a first filter sensor (not shown) installed in the first filter (123) to detect the state of the first filter (123) is further included, and when the measured value by the first filter sensor exceeds a preset standard value of solid carbon dioxide, the third globe valve (124) can be closed and the fourth globe valve (126) can be opened, and in addition, the first filter (123) and the second filter (125) can each include a heater to melt the solid carbon dioxide.

[0115] For example, if the unloading of liquefied carbon dioxide continues for a long time, solid carbon dioxide accumulates in the first filter (123), and at this time, if the first filter sensor detects that the solid carbon dioxide exceeds the standard, the third globe valve (124) can be locked and the fourth globe valve (126) can be opened to continuously unload the liquefied carbon dioxide through the second unloading pipe (121b).

[0116] Next, the pressure relief unit (160) prevents damage caused by excessive pressure due to evaporated gas inside the liquefied carbon dioxide storage tank (110).

[0117] Here, the pressure relief unit (160) may include a safety pipe (161) connected to a liquefied carbon dioxide storage tank (110), and a PRV (Pressure Relief Valve) (162) installed in the safety pipe (161) to discharge vaporized carbon dioxide, which is an evaporation gas, from the liquefied carbon dioxide storage tank (110).

[0118] In addition, the safety pipe (161) and PRV (162) are configured as a pair, so that stable operation can be achieved in case one of the safety pipes (161) and PRV (162) does not operate.

[0119] In addition, the PRV (162) may be configured in multiple units, and may further include one or more connecting pipes (163) that interconnect the multiple PRVs (162) and are connected to the venting pipe (172), and an internal observation unit (not shown) that is installed on the connecting pipe (163) and visually identifies whether solid carbon dioxide is generated inside the connecting pipe (163).

[0120] Next, the fourth gas supply unit (170) supplies the vaporized carbon dioxide that has passed through the pressure discharge unit (160) to the unloading pipe (121) of the unloading pipe unit (120) to maintain the internal pressure of the unloading pipe (121) and remove solid carbon dioxide.

[0121] Specifically, the fourth gas supply unit (170) may include a knockout drum tank (171) that is connected to the rear end of the safety pipe (161) and temporarily stores vaporized carbon dioxide (and / or solid carbon dioxide) discharged through the PRV (162), a venting pipe (172) that connects the safety pipe (161) and the knockout drum tank (171), and a fifth globe valve (173) that is formed at the rear end of the knockout drum tank (171) and controls the flow rate of vaporized carbon dioxide to the unloading pipe (121).

[0122] Here, not only the vaporized carbon dioxide but also the solid carbon dioxide generated during the emission process can be captured in the knockout drum tank (171), and the knockout drum tank (171) can be implemented as a type of gas-liquid separator that separates and captures gas and liquid, and the venting pipe (172) connects the PRV (162) and the knockout drum tank (171) and can vent the vaporized carbon dioxide that has passed through the PRV (162).

[0123] Additionally, a recovery pipe (174) may be formed to supply vaporized carbon dioxide from the knockout drum tank (171) to a liquefied carbon dioxide storage tank (110) to maintain the internal pressure at a certain level.

[0124] Meanwhile, the knockout drum tank (171) temporarily stores the vaporized carbon dioxide, i.e., the vaporized gas that has passed through the PRV (162), and even if solid carbon dioxide is formed due to a temperature drop caused by a pressure drop during the discharge and transport process of the vaporized gas, it can be temporarily stored, and over time, the solid carbon dioxide stored in the knockout drum tank (171) can be vaporized again into vaporized carbon dioxide.

[0125] In addition, a first pressure sensor (PT) and a first temperature sensor (TT) disposed inside the liquefied carbon dioxide storage tank (110) for measuring pressure and temperature, and a second pressure sensor (P) and a second temperature sensor (T) disposed in the unloading pipe (121) for measuring pressure and temperature are further included, and the first measurement value by the first pressure sensor (PT) and the first temperature sensor (TT) and the second measurement value by the second pressure sensor (P) and the second temperature sensor (T) are fed back, thereby preventing the generation of solid carbon dioxide inside the liquefied carbon dioxide storage tank (110) or removing solid carbon dioxide inside the unloading pipe (121).

[0126] In addition, a third gas supply unit (130-1) is further included to supply the vaporized carbon dioxide produced by forcibly vaporizing the liquefied carbon dioxide supplied from the liquefied carbon dioxide storage tank (110) to the unloading pipe (121), and, depending on the second measurement values ​​by the second pressure sensor (P) and the second temperature sensor (T), the carbon dioxide produced by the fourth gas supply unit (170) or the vaporized carbon dioxide produced by forcibly vaporizing by the third gas supply unit (130-1) can be selectively supplied to the unloading pipe (121).

[0127] Meanwhile, as another example, a liquefied carbon dioxide carrier equipped with the pressure control system listed above is provided.

[0128] Accordingly, by configuring a liquefied carbon dioxide carrier equipped with the pressure control system and the system as described above, the evaporated gas exhausted from the PRV is captured and vaporized carbon dioxide is generated and utilized to maintain the internal pressure of the unloading pipe, thereby preventing the phenomenon of pipe blockage caused by solidification of the liquefied carbon dioxide due to a temperature drop caused by a pressure drop inside the liquefied carbon dioxide storage tank and / or in the unloading pipe when unloading the liquefied carbon dioxide.

[0129] A pressure control system according to a third embodiment of the present invention comprises a liquefied carbon dioxide storage tank (110) for storing liquefied carbon dioxide, a pressure discharge unit (160) for preventing damage to the liquefied carbon dioxide storage tank (110) by evaporation gas inside the liquefied carbon dioxide storage tank (110), and a re-liquefaction unit (180) for storing vaporized carbon dioxide, which is evaporation gas discharged through the pressure discharge unit (160), and re-liquefying the vaporized carbon dioxide by a self-heat exchange method and returning it to the liquefied carbon dioxide storage tank (110), thereby re-liquefying the evaporation gas without a separate refrigerant.

[0130] Hereinafter, with reference to FIG. 3, the pressure control system of the above-described configuration will be described in detail as follows.

[0131] First, a liquefied carbon dioxide storage tank (110) is installed on a liquefied carbon dioxide carrier to store and transport liquefied carbon dioxide supplied through a bunkering line (111).

[0132] Here, the liquefied carbon dioxide storage tank (110) may be an insulated tank in which liquefied carbon dioxide is stored, and may be an IMO type C storage tank. The IMO type C has an independent pressure vessel form and can be easily installed on the hull.

[0133] The liquefied carbon dioxide may be liquefied carbon dioxide captured by a carbon capture system (CCS) on land or at sea, or liquefied carbon dioxide captured by an onboard carbon dioxide capture system (not shown) from the ship's engine.

[0134] Additionally, the liquefied carbon dioxide storage tank (110) may be equipped with a level sensor (LT) for measuring the level of liquefied carbon dioxide, a temperature transmitter (TT) for measuring temperature, and a pressure transmitter (PT) for measuring pressure.

[0135] Referring to FIG. 7, the liquefied carbon dioxide storage tank (110) can store liquefied carbon dioxide by maintaining the inside thereof at a temperature of -30°C to -55°C and a pressure of 5 to 19 bar, preferably at a temperature of -45°C to -55°C and a pressure of 5.5 to 7.5 bar, and the tank control system (not shown) controls the temperature, pressure, etc. of the liquefied carbon dioxide inside the liquefied carbon dioxide storage tank (110) to store the liquefied carbon dioxide normally.

[0136] In addition, a plurality of bunkering lines (111) may be provided, and some of the plurality may be connected to the upper part of the liquid carbon dioxide storage tank (110) and configured with one end as a spray nozzle to be used as a bunkering line for cool-down.

[0137] Next, the pressure relief unit (160) prevents damage caused by excessive pressure due to evaporated gas inside the liquefied carbon dioxide storage tank (110).

[0138] Here, the pressure relief unit (160) may include a safety pipe (161) connected to a liquefied carbon dioxide storage tank (110), and a PRV (Pressure Relief Valve) (162) installed in the safety pipe (161) to discharge vaporized carbon dioxide from the liquefied carbon dioxide storage tank (110).

[0139] In addition, the safety pipe (161) and PRV (162) are configured as a pair, so that stable operation can be achieved in case one of the safety pipes (161) and PRV (162) does not operate.

[0140] In addition, the PRV (162) may be configured in multiple units, and may further include one or more connecting pipes (163) that interconnect the multiple PRVs (162) and are connected to a venting pipe (182), and an internal observation unit (not shown) that is installed on the connecting pipe (163) and visually identifies whether solid carbon dioxide is generated inside the connecting pipe (163).

[0141] Next, the re-liquefaction unit (180) stores the evaporated gas, re-liquefies the evaporated gas through self-heat exchange, and returns it to the liquefied carbon dioxide storage tank (110).

[0142] Specifically, referring to FIG. 3, the re-liquefaction unit (180) includes a buffer tank (181) that is coupled to the rear end of a safety pipe (161) and stores vaporized carbon dioxide, which is vaporized gas discharged through a pressure relief unit (160), a venting pipe (182) that connects the safety pipe (161) and the buffer tank (181), a first compressor (183) that compresses vaporized carbon dioxide transferred from the buffer tank (181), a pressure control valve (PV) that is coupled between the buffer tank (181) and the first compressor (183) and controls the pressure of the vaporized carbon dioxide, a condenser (184) that is coupled to the rear end of the first compressor (183) and condenses the vaporized carbon dioxide, a second compressor (185) that is coupled to the rear end of the condenser (184) and compresses the vaporized carbon dioxide, and a second compressor (185) that is coupled to the rear end of the second compressor (185) and It may be composed of a Joule Thomson valve (186) for expanding vaporized carbon dioxide, a gas-liquid separator (187) coupled to the rear end of the Joule Thomson valve (186) for separating vaporized carbon dioxide and liquid carbon dioxide, a first recovery pipe (188) for recovering the vaporized carbon dioxide separated by the gas-liquid separator (187) to a condenser (184), and an injection nozzle (not shown) for injecting the liquefied carbon dioxide separated by the gas-liquid separator (187) to the condenser (184) through the first recovery line (RL1) to condense the vaporized carbon dioxide.

[0143] Through this configuration, the vaporized carbon dioxide and liquefied carbon dioxide separated by the gas-liquid separator (187) are recovered by the condenser (184), thereby inducing a property change by allowing the gas and liquid to be mixed and condensed, thereby enabling re-liquefaction of the vaporized carbon dioxide without a separate refrigerant.

[0144] Here, the buffer tank (181) may be an IMO type C pressure tank that can withstand up to a certain pressure.

[0145] Additionally, some of the liquefied carbon dioxide condensed and liquefied by the condenser (184) can be recovered to the liquefied carbon dioxide storage tank (110) through the second recovery pipe (189).

[0146] That is, some of the liquefied carbon dioxide separated by the gas-liquid separator (187) can be recovered to the liquefied carbon dioxide storage tank (110) through the second recovery line (RL2), and some of the liquefied carbon dioxide from the gas-liquid separator (187) can be sprayed through a nozzle formed at the top of the condenser (184) to contact the vaporized carbon dioxide and condense the vaporized carbon dioxide, thereby re-liquefying it through self-heat exchange.

[0147] Although the Joule-Thompson valve is used as an example of an expansion means, it is not limited thereto, and various expansion means such as an expander can be applied, and the same applies hereinafter.

[0148] Meanwhile, as another example, a liquefied carbon dioxide carrier equipped with the pressure control system listed above is provided.

[0149] Therefore, by configuring a liquefied carbon dioxide carrier equipped with the pressure control system and the same system as described above, the evaporated gas can be stored and re-liquefied by a self-heat exchange method without a separate refrigerant or expensive heat exchange equipment.

[0150] A pressure control system according to a fourth embodiment of the present invention comprises a liquefied carbon dioxide storage tank (110) for storing liquefied carbon dioxide, a pressure discharge unit (160) for preventing damage to the liquefied carbon dioxide storage tank (110) due to excessive pressure caused by the boil-off gas inside the liquefied carbon dioxide storage tank (110), a re-liquefaction unit (180) for storing the vaporized carbon dioxide, which is the boil-off gas discharged through the pressure discharge unit (160), and for re-liquefying it by a vaporized carbon dioxide self-heat exchange method and returning it to the liquefied carbon dioxide storage tank (110), and a re-liquefaction supply unit (130-2) for supplying the liquefied carbon dioxide stored in the liquefied carbon dioxide storage tank (110) to the re-liquefaction unit (180) during the initial operation of the re-liquefaction unit (180), thereby improving the performance of the re-liquefaction unit (180). The point is to maintain it.

[0151] Hereinafter, with reference to FIG. 4, the pressure control system of the above-described configuration will be described in detail as follows.

[0152] First, a liquefied carbon dioxide storage tank (110) is installed on a liquefied carbon dioxide carrier to store and transport liquefied carbon dioxide supplied through a bunkering line (111).

[0153] Here, the liquefied carbon dioxide storage tank (110) may be an insulated tank in which liquefied carbon dioxide is stored, and may be an IMO type C storage tank. The IMO type C has an independent pressure vessel form and can be easily installed on the hull.

[0154] The liquefied carbon dioxide may be liquefied carbon dioxide captured by a carbon capture system (CCS) on land or at sea, or liquefied carbon dioxide captured by an onboard carbon dioxide capture system (not shown) from the ship's engine.

[0155] Additionally, the liquefied carbon dioxide storage tank (110) may be equipped with a level sensor (LT) for measuring the level of liquefied carbon dioxide, a temperature transmitter (TT) for measuring temperature, and a pressure transmitter (PT) for measuring pressure.

[0156] Referring to FIG. 7, the liquefied carbon dioxide storage tank (110) can store liquefied carbon dioxide by maintaining the inside thereof at a temperature of -30°C to -55°C and a pressure of 5 to 19 bar, preferably at a temperature of -45°C to -55°C and a pressure of 5.5 to 7.5 bar, and the tank control system (not shown) controls the temperature, pressure, etc. of the liquefied carbon dioxide inside the liquefied carbon dioxide storage tank (110) to store the liquefied carbon dioxide normally.

[0157] In addition, a plurality of bunkering lines (111) may be provided, and some of the plurality may be connected to the upper part of the liquid carbon dioxide storage tank (110) and configured with one end as a spray nozzle to be used as a bunkering line for cool-down.

[0158] Next, the pressure relief unit (160) prevents damage caused by excessive pressure due to evaporated gas inside the liquefied carbon dioxide storage tank (110).

[0159] Here, the pressure relief unit (160) may include a safety pipe (161) connected to a liquefied carbon dioxide storage tank (110), and a PRV (Pressure Relief Valve) (162) installed in the safety pipe (161) to discharge vaporized carbon dioxide, which is an evaporation gas, from the liquefied carbon dioxide storage tank (110).

[0160] In addition, the safety pipe (161) and PRV (162) are configured as a pair, so that stable operation can be achieved in case one of the safety pipes (161) and PRV (162) does not operate.

[0161] In addition, the PRV (162) may be configured in multiple units, and may further include one or more connecting pipes (163) that interconnect the multiple PRVs (162) and are connected to a venting pipe (182), and an internal observation unit (not shown) that is installed on the connecting pipe (163) and visually identifies whether solid carbon dioxide is generated inside the connecting pipe (163).

[0162] Next, the re-liquefaction unit (180) stores the evaporated gas, re-liquefies the evaporated gas through self-heat exchange, and returns it to the liquefied carbon dioxide storage tank (110).

[0163] Specifically, referring to FIG. 4, the re-liquefaction unit (180) includes a buffer tank (181) coupled to the rear end of a safety pipe (161) and storing vaporized carbon dioxide, which is vaporized gas discharged through a pressure discharge unit (160), a venting pipe (182) connecting the safety pipe (161) and the buffer tank (181), a first compressor (183) for compressing vaporized carbon dioxide transferred from the buffer tank (181), a pressure control valve (PV) coupled between the buffer tank (181) and the first compressor (183) and controlling the pressure of the vaporized carbon dioxide, a condenser (184) coupled to the rear end of the first compressor (183) and condensing the vaporized carbon dioxide, a second compressor (185) coupled to the rear end of the condenser (184) and compressing the vaporized carbon dioxide, and a second compressor (185) coupled to the rear end of the second compressor (185) and It may be composed of a Joule Thomson valve (186) for expanding vaporized carbon dioxide, a gas-liquid separator (187) coupled to the rear end of the Joule Thomson valve (186) for separating vaporized carbon dioxide and liquid carbon dioxide, a first recovery pipe (188) for recovering the vaporized carbon dioxide separated by the gas-liquid separator (187) to a condenser (184), and an injection nozzle (not shown) for injecting the liquefied carbon dioxide separated by the gas-liquid separator (187) to the condenser (184) through the first recovery line (RL1) to condense the vaporized carbon dioxide.

[0164] Through this configuration, the vaporized carbon dioxide and liquefied carbon dioxide separated by the gas-liquid separator (187) are recovered by the condenser (184), so that the gas and liquid are mixed and condensed to induce a property change, thereby enabling re-liquefaction of the vaporized carbon dioxide without a separate refrigerant.

[0165] Here, the buffer tank (181) may be an IMO type C pressure tank that can withstand up to a certain pressure.

[0166] Additionally, some of the liquefied carbon dioxide condensed and liquefied by the condenser (184) can be recovered to the liquefied carbon dioxide storage tank (110) through the second recovery pipe (189).

[0167] That is, some of the liquefied carbon dioxide separated by the gas-liquid separator (187) can be recovered to the liquefied carbon dioxide storage tank (110) through the second recovery line (RL2), and some of the liquefied carbon dioxide from the gas-liquid separator (187) can be sprayed through a nozzle formed at the top of the condenser (184) to contact the vaporized carbon dioxide and condense the vaporized carbon dioxide, thereby re-liquefying it through self-heat exchange.

[0168] Next, the re-liquefaction supply unit (130-2) supplies liquefied carbon dioxide stored in the liquefied carbon dioxide storage tank (110) to the re-liquefaction unit (180) at the time of initial operation of the re-liquefaction unit (180), thereby providing a certain amount of liquefied carbon dioxide required for initial operation of the re-liquefaction unit (180), thereby enabling the condenser (184) to effectively exhibit its performance from the beginning of re-liquefaction.

[0169] Here, the re-liquefaction supply unit (130-2) may also function as a pressure maintenance unit to prevent the generation of solid carbon dioxide by preventing a temperature drop due to a pressure drop inside the liquefied carbon dioxide storage tank (110).

[0170] That is, specifically, the pressure maintenance unit may be composed of a circulation pipe (131) connected from one side to the other side of the liquefied carbon dioxide storage tank (110), a pressure control valve (133) installed in the circulation pipe (131) to control the pressure of the liquefied carbon dioxide, a PBU (Pressure Buildup Unit) (132) installed in front of the pressure control valve (133) to monitor the internal pressure of the liquefied carbon dioxide storage tank (110) and forcibly vaporize the liquefied carbon dioxide, and a control valve (134) to control the flow rate of the vaporized carbon dioxide forcibly vaporized through the circulation pipe (131) and return it to the liquefied carbon dioxide storage tank (110).

[0171] At this time, the re-liquefaction supply unit (130-2) may be composed of an initial operation pipe (135) branched from the circulation pipe (131) between the pressure control valve (133) and the PBU (132) and connected to the condenser (184) of the re-liquefaction unit (180), and a pump (not shown) that supplies liquefied carbon dioxide to the condenser through the initial operation pipe (135).

[0172] Meanwhile, as another example, a liquefied carbon dioxide carrier equipped with the pressure control system listed above is provided.

[0173] Therefore, by configuring a liquefied carbon dioxide carrier equipped with the pressure control system and the same as described above, when the re-liquefaction unit is initially operated, liquefied carbon dioxide from the liquefied carbon dioxide storage tank is supplied to maintain the performance of the re-liquefaction unit, and the evaporated gas can be stored and re-liquefied by a self-heat exchange method without a separate refrigerant or expensive heat exchange equipment.

[0174] The pressure control system according to the fifth embodiment of the present invention includes a liquefied carbon dioxide storage tank (110) for storing liquefied carbon dioxide, a pressure discharge unit (160) for preventing damage to the liquefied carbon dioxide storage tank (110) due to excessive pressure caused by evaporation gas inside the liquefied carbon dioxide storage tank (110), and a gas supply unit (190) for supplying evaporated carbon dioxide passing through the pressure discharge unit (160) to an ALS (Air Lubrication System) or a BWTS (Ballast Water Treatment System), thereby enabling the evaporation gas to be utilized in various ways within a ship.

[0175] Hereinafter, with reference to FIG. 5, the pressure control system of the above-described configuration will be described in detail as follows.

[0176] First, a liquefied carbon dioxide storage tank (110) is installed on a liquefied carbon dioxide carrier to store and transport liquefied carbon dioxide supplied through a bunkering line (111).

[0177] Here, the liquefied carbon dioxide storage tank (110) may be an insulated tank in which liquefied carbon dioxide is stored, and may be an IMO type C storage tank. The IMO type C has an independent pressure vessel form and can be easily installed on the hull.

[0178] The liquefied carbon dioxide may be liquefied carbon dioxide captured by a carbon capture system (CCS) on land or at sea, or liquefied carbon dioxide captured by an onboard carbon dioxide capture system (not shown) from the ship's engine.

[0179] Additionally, the liquefied carbon dioxide storage tank (110) may be equipped with a level sensor (LT) for measuring the level of liquefied carbon dioxide, a temperature transmitter (TT) for measuring temperature, and a pressure transmitter (PT) for measuring pressure.

[0180] Referring to FIG. 7, the liquefied carbon dioxide storage tank (110) can store liquefied carbon dioxide by maintaining the inside thereof at a temperature of -30°C to -55°C and a pressure of 5 to 19 bar, preferably at a temperature of -45°C to -55°C and a pressure of 5.5 to 7.5 bar, and the tank control system (not shown) controls the temperature, pressure, etc. of the liquefied carbon dioxide inside the liquefied carbon dioxide storage tank (110) to store the liquefied carbon dioxide normally.

[0181] In addition, a plurality of bunkering lines (111) may be provided, and some of the plurality may be connected to the upper part of the liquid carbon dioxide storage tank (110) and configured with one end as a spray nozzle to be used as a bunkering line for cool-down.

[0182] Next, the pressure relief unit (160) prevents damage caused by excessive pressure due to evaporated gas inside the liquefied carbon dioxide storage tank (110).

[0183] Here, the pressure relief unit (160) may include a safety pipe (161) connected to a liquefied carbon dioxide storage tank (110), and a PRV (Pressure Relief Valve) (162) installed in the safety pipe (161) to discharge vaporized carbon dioxide from the liquefied carbon dioxide storage tank (110).

[0184] In addition, the safety pipe (161) and PRV (162) are configured as a pair, so that stable operation can be achieved in case one of the safety pipes (161) and PRV (162) does not operate.

[0185] In addition, the PRV (162) may be configured in multiple units, and may further include one or more connecting pipes (163) that interconnect the multiple PRVs (162) and are connected to the venting pipe (172), and an internal observation unit (not shown) that is installed on the connecting pipe (163) and visually identifies whether solid carbon dioxide is generated inside the connecting pipe (163).

[0186] Next, the gas supply unit (190) supplies the vaporized carbon dioxide, which is the evaporated gas discharged through the pressure discharge unit (160), to the ALS (Air Lubrication System) or the BWTS (Ballast Water Treatment System).

[0187] That is, the gas supply unit (190) can compress the vaporized carbon dioxide, which is the vaporized gas discharged through the pressure discharge unit (160), through the ALS, dissolve it in seawater, and spray it onto the ship's bottom to increase operating efficiency and implement anti-fouling, or can dissolve the vaporized carbon dioxide, which is the vaporized gas discharged through the pressure discharge unit (160), through the BWTS, in ballast water to lower the pH of the ballast water, thereby effectively killing microorganisms.

[0188] ALS is an air lubrication system. It is a technology that reduces hull resistance and improves operating efficiency by injecting compressed air into the hull bottom. Instead of conventionally compressing atmospheric air and injecting it into the hull bottom, the fifth embodiment of the present invention utilizes compressed, vaporized carbon dioxide dissolved in seawater and then injects it into the hull bottom. This vaporized carbon dioxide, when dissolved in seawater, lowers the pH of the seawater, thereby contributing to antifouling of the hull bottom in addition to the air lubrication system.

[0189] Meanwhile, the ALS may further include a compressor for compressing the vaporized carbon dioxide, and may implement either a system that directly injects the vaporized carbon dioxide into the hull or a system that pre-dissolves it in seawater and then injects it into the hull.

[0190] Furthermore, BWTS is a ballast water treatment system, and is a technology that kills microorganisms contained in ballast water before its discharge. Instead of using conventional chemicals or substances to kill microorganisms, the fifth embodiment of the present invention effectively kills microorganisms by dissolving vaporized carbon dioxide in ballast water (seawater) to lower the pH of the ballast water. In this case, it is also possible to use existing chemicals or substances in parallel with dissolving vaporized carbon dioxide in seawater.

[0191] Specifically, referring to FIG. 5, the gas supply unit (190) may be composed of a buffer tank (191) that is connected to the rear end of the safety pipe (161) and stores vaporized carbon dioxide, which is vaporized gas discharged through the pressure relief unit (160), a venting pipe (192) that connects the safety pipe (161) and the buffer tank (191), a sixth globe valve (193) that is formed at the rear end of the buffer tank (191) and supplies the vaporized carbon dioxide by controlling the flow rate of the ALS, and a seventh globe valve (194) that is formed at the rear end of the buffer tank (191) and supplies the vaporized carbon dioxide by controlling the flow rate of the BWTS.

[0192] In addition, the gas supply unit (190) may further include an eighth globe valve (195) that controls the flow rate of vaporized carbon dioxide to the liquefied carbon dioxide storage tank (110) and supplies it to maintain the internal pressure of the liquefied carbon dioxide storage tank (110) at a constant level.

[0193] Meanwhile, as another example, a liquefied carbon dioxide carrier equipped with the pressure control system listed above is provided.

[0194] Therefore, by configuring a liquefied carbon dioxide carrier equipped with the pressure control system and the same as described above, the evaporated gas vented through the PRV can be stored and utilized in various ways within the ship to increase operating efficiency, implement anti-fouling performance, kill microorganisms in ballast water, and utilize it to maintain the internal pressure of the tank.

[0195] A pressure control system according to a sixth embodiment of the present invention comprises a liquefied carbon dioxide storage tank (110) for storing liquefied carbon dioxide, a pressure discharge unit (160) for preventing damage to the liquefied carbon dioxide storage tank (110) due to excessive pressure caused by vaporized gas inside the liquefied carbon dioxide storage tank (110), a gas supply unit (190) for supplying vaporized carbon dioxide passing through the pressure discharge unit (160) to an ALS (Air Lubrication System) or a BWTS (Ballast Water Treatment System), and a gas supplement unit (200) for supplementing the shortage of vaporized carbon dioxide by the gas supply unit (190), thereby forcibly vaporizing liquefied carbon dioxide stored in the liquefied carbon dioxide storage tank to supplement the shortage of vaporized carbon dioxide in the gas supply unit.

[0196] Hereinafter, with reference to FIG. 6, the pressure control system of the above-described configuration will be described in detail as follows.

[0197] First, a liquefied carbon dioxide storage tank (110) is installed on a liquefied carbon dioxide carrier to store and transport liquefied carbon dioxide supplied through a bunkering line (111).

[0198] Here, the liquefied carbon dioxide storage tank (110) may be an insulated tank in which liquefied carbon dioxide is stored, and may be an IMO type C storage tank. The IMO type C has an independent pressure vessel form and can be easily installed on the hull.

[0199] The liquefied carbon dioxide may be liquefied carbon dioxide captured by a carbon capture system (CCS) on land or at sea, or liquefied carbon dioxide captured by an onboard carbon dioxide capture system (not shown) from the ship's engine.

[0200] Additionally, the liquefied carbon dioxide storage tank (110) may be equipped with a level sensor (LT) for measuring the level of liquefied carbon dioxide, a temperature transmitter (TT) for measuring temperature, and a pressure transmitter (PT) for measuring pressure.

[0201] Referring to FIG. 7, the liquefied carbon dioxide storage tank (110) can store liquefied carbon dioxide by maintaining the inside thereof at a temperature of -30°C to -55°C and a pressure of 5 to 19 bar, preferably at a temperature of -45°C to -55°C and a pressure of 5.5 to 7.5 bar, and the tank control system (not shown) controls the temperature, pressure, etc. of the liquefied carbon dioxide inside the liquefied carbon dioxide storage tank (110) to store the liquefied carbon dioxide normally.

[0202] In addition, a plurality of bunkering lines (111) may be provided, and some of the plurality may be connected to the upper part of the liquid carbon dioxide storage tank (110) and configured with one end as a spray nozzle to be used as a bunkering line for cool-down.

[0203] Next, the pressure relief unit (160) prevents damage caused by excessive pressure due to evaporated gas inside the liquefied carbon dioxide storage tank (110).

[0204] Here, the pressure relief unit (160) may include a safety pipe (161) connected to a liquefied carbon dioxide storage tank (110), and a PRV (Pressure Relief Valve) (162) installed in the safety pipe (161) to discharge vaporized carbon dioxide from the liquefied carbon dioxide storage tank (110).

[0205] In addition, the safety pipe (161) and PRV (162) are configured as a pair, so that stable operation can be achieved in case one of the safety pipes (161) and PRV (162) does not operate.

[0206] In addition, the PRV (162) may be configured in multiple units, and may further include one or more connecting pipes (163) that interconnect the multiple PRVs (162) and are connected to the venting pipe (172), and an internal observation unit (not shown) that is installed on the connecting pipe (163) and visually identifies whether solid carbon dioxide is generated inside the connecting pipe (163).

[0207] Next, the gas supply unit (190) supplies the vaporized carbon dioxide that has passed through the pressure discharge unit (160) to the ALS (Air Lubrication System) or the BWTS (Ballast Water Treatment System).

[0208] That is, the gas supply unit (190) can compress the vaporized carbon dioxide, which is the vaporized gas discharged through the pressure discharge unit (160), through the ALS, dissolve it in seawater, and spray it onto the ship's bottom to increase operating efficiency and implement anti-fouling, or can dissolve the vaporized carbon dioxide, which is the vaporized gas discharged through the pressure discharge unit (160), through the BWTS, in ballast water to lower the pH of the ballast water, thereby effectively killing microorganisms.

[0209] ALS is an air lubrication system. It is a technology that reduces hull resistance and improves operating efficiency by injecting compressed air into the hull bottom. Instead of conventionally compressing atmospheric air and injecting it into the hull bottom, the fifth embodiment of the present invention utilizes compressed, vaporized carbon dioxide dissolved in seawater and then injects it into the hull bottom. This vaporized carbon dioxide, when dissolved in seawater, lowers the pH of the seawater, thereby contributing to antifouling of the hull bottom in addition to the air lubrication system.

[0210] Meanwhile, the ALS may further include a compressor for compressing the vaporized carbon dioxide, and may implement either a system that directly injects the vaporized carbon dioxide into the hull or a system that pre-dissolves it in seawater and then injects it into the hull.

[0211] Furthermore, BWTS is a ballast water treatment system, and is a technology that kills microorganisms contained in ballast water before its discharge. Instead of using conventional chemicals or substances to kill microorganisms, the fifth embodiment of the present invention effectively kills microorganisms by dissolving vaporized carbon dioxide in ballast water (seawater) to lower the pH of the ballast water. In this case, it is also possible to use existing chemicals or substances in parallel with dissolving vaporized carbon dioxide in seawater.

[0212] Specifically, referring to FIG. 6, the gas supply unit (190) may be composed of a buffer tank (191) that is connected to the rear end of the safety pipe (161) and stores vaporized carbon dioxide, which is vaporized gas discharged through the pressure relief unit (160), a venting pipe (192) that connects the safety pipe (161) and the buffer tank (191), a sixth globe valve (193) that is formed at the rear end of the buffer tank (191) and supplies the vaporized carbon dioxide by controlling the flow rate of the ALS, and a seventh globe valve (194) that is formed at the rear end of the buffer tank (191) and supplies the vaporized carbon dioxide by controlling the flow rate of the BWTS.

[0213] In addition, the gas supply unit (190) may further include an eighth globe valve (195) that controls the flow rate of vaporized carbon dioxide to the liquefied carbon dioxide storage tank (110) and supplies it to maintain the internal pressure of the liquefied carbon dioxide storage tank (110) at a constant level.

[0214] Additionally, the buffer tank (191) may be an IMO type C pressure tank capable of withstanding up to a certain pressure.

[0215] Next, the gas replenishment unit (200) can compensate for the shortage of vaporized carbon dioxide by the gas supply unit (190), thereby forcibly vaporizing the liquefied carbon dioxide stored in the liquefied carbon dioxide storage tank (110) to compensate for the shortage of vaporized carbon dioxide in the gas supply unit (190).

[0216] Specifically, the gas replenishment unit (200) may be composed of a pump (201) that pumps liquefied carbon dioxide from a liquefied carbon dioxide storage tank (110) to a gas supply unit (190), and an evaporator (202) that forcibly vaporizes the liquefied carbon dioxide supplied by the pump (201) to generate forcibly vaporized vaporized carbon dioxide and supplies the forcibly vaporized vaporized carbon dioxide to a buffer tank (191) of the gas supply unit (190).

[0217] Here, the buffer tank (191) includes a pressure sensor (not shown) that measures the pressure of the vaporized carbon dioxide, and according to the measured value by the pressure sensor, the gas replenishment unit (200) can supply the shortage of the vaporized carbon dioxide to the buffer tank (191).

[0218] In addition, a branch pipe (203) may be further included to supply forcibly vaporized carbon dioxide by being connected to the rear end of the evaporator (202) and diverted into the liquefied carbon dioxide storage tank (110), thereby maintaining the internal pressure of the liquefied carbon dioxide storage tank (110).

[0219] Meanwhile, as another example, a liquefied carbon dioxide carrier equipped with the pressure control system listed above is provided.

[0220] Accordingly, by configuring a liquefied carbon dioxide carrier equipped with the pressure control system and the system as described above, the liquefied carbon dioxide stored in the liquefied carbon dioxide storage tank is forcibly vaporized to supplement the shortage of vaporized carbon dioxide in the gas supply section, and the vaporized gas vented through the PRV is stored and utilized in various ways within the ship to increase operating efficiency, implement antifouling performance, kill microorganisms in ballast water, and utilize it to maintain the internal pressure of the tank.

[0221] The embodiments described in this specification and the configurations illustrated in the drawings are only the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention. Therefore, it should be understood that there may be various equivalents and modified examples that can replace them at the time of filing this application.

Claims

1. A liquefied carbon dioxide storage tank for storing liquefied carbon dioxide; A pressure relief unit that prevents damage to the liquefied carbon dioxide storage tank due to excessive pressure caused by evaporated gas inside the liquefied carbon dioxide storage tank; and A gas supply unit that supplies vaporized carbon dioxide that has passed through the pressure discharge unit to an ALS (Air Lubrication System) or a BWTS (Ballast Water Treatment System); Pressure control system.

2. In paragraph 1, The above gas supply unit is characterized in that it compresses the vaporized carbon dioxide, which is the vaporized gas discharged through the pressure discharge unit through the ALS, dissolves it in seawater, and sprays it to the ship's bottom. Pressure control system.

3. In paragraph 1, The above gas supply unit is characterized in that it dissolves the vaporized carbon dioxide, which is the vaporized gas discharged through the pressure discharge unit through the BWTS, into the equilibrium water to lower the pH of the equilibrium water. Pressure control system.

4. In paragraph 1, The above pressure relief unit is, A safety pipe connected to the above liquefied carbon dioxide storage tank, and, Characterized in that it includes a PRV (Pressure Relief Valve) installed in the above safety pipe and discharging vaporized carbon dioxide from the liquefied carbon dioxide storage tank. Pressure control system.

5. In paragraph 4, The above safety pipe and the PRV are characterized in that they are each configured as a pair. Pressure control system.

6. In paragraph 4, The above gas supply unit, A buffer tank that is connected to the rear end of the safety pipe and stores the vaporized carbon dioxide, which is the vaporized gas discharged through the pressure relief unit, A venting pipe connecting the above safety pipe and the above buffer tank, A sixth globe valve formed at the rear end of the above buffer tank and supplying vaporized carbon dioxide to the ALS, and, It is characterized by being formed at the rear end of the buffer tank and comprising a seventh globe valve that supplies vaporized carbon dioxide to the BWTS. Pressure control system.

7. In paragraph 6, The gas supply unit is characterized in that it further includes an eighth globe valve for supplying vaporized carbon dioxide to the liquefied carbon dioxide storage tank. Pressure control system.

8. A liquefied carbon dioxide carrier equipped with a pressure control system as described in any one of paragraphs 1 to 7.

9. Liquefied carbon dioxide storage tank for storing liquefied carbon dioxide; A pressure relief unit that prevents damage to the liquefied carbon dioxide storage tank due to excessive pressure caused by evaporated gas inside the liquefied carbon dioxide storage tank; A gas supply unit that supplies the vaporized carbon dioxide that has passed through the pressure discharge unit to an ALS (Air Lubrication System) or BWTS (Ballast Water Treatment System); and A gas replenishment unit that replenishes the shortage of vaporized carbon dioxide by the above gas supply unit; Pressure control system.

10. In paragraph 9, The above pressure relief unit is, A safety pipe connected to the above liquefied carbon dioxide storage tank, and, Characterized in that it includes a PRV (Pressure Relief Valve) installed in the above safety pipe and discharging vaporized carbon dioxide from the liquefied carbon dioxide storage tank. Pressure control system.

11. In paragraph 10, The above safety pipe and the PRV are characterized in that they are each configured as a pair. Pressure control system.

12. In paragraph 10, The above gas supply unit, A buffer tank that is connected to the rear end of the safety pipe and stores the vaporized carbon dioxide, which is the vaporized gas discharged through the pressure relief unit, A venting pipe connecting the above safety pipe and the above buffer tank, A sixth globe valve that controls the flow rate of vaporized carbon dioxide to the above ALS, A seventh globe valve that controls the flow rate of vaporized carbon dioxide to the above BWTS, and, It is characterized by comprising an eighth globe valve that controls the flow rate of vaporized carbon dioxide into the liquefied carbon dioxide storage tank. Pressure control system.

13. In paragraph 12, The above buffer tank is characterized in that it is an IMO type C tank. Pressure control system.

14. In paragraph 12, The above gas replenishment unit is, A pump for pumping liquefied carbon dioxide from the above liquefied carbon dioxide storage tank, and, It is characterized by comprising an evaporator that forcibly vaporizes liquefied carbon dioxide supplied by the pump to produce forcibly vaporized carbon dioxide. Pressure control system.

15. In paragraph 14, The above buffer tank includes a pressure sensor that measures the pressure of vaporized carbon dioxide, According to the measurement value by the pressure sensor, the gas replenishment unit is characterized in that it supplies the shortage of vaporized carbon dioxide to the buffer tank. Pressure control system.

16. In paragraph 14, It is characterized in that it further includes a branch pipe that is connected to the rear end of the evaporator and supplies the forcedly vaporized vaporized carbon dioxide by diverting it into the inside of the liquefied carbon dioxide storage tank to maintain the internal pressure of the liquefied carbon dioxide storage tank. Pressure control system.

17. A liquefied carbon dioxide carrier equipped with a pressure control system as described in any one of paragraphs 9 to 16.

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