Gas treatment system and ship including same

Abstract

The present invention relates to a gas treatment system and a ship including same. The gas treatment system includes a reliquefaction unit for reliquefying a gaseous material discharged from a storage tank, wherein the storage tank stores at least one of a first material and a second material, the reliquefaction unit includes: a first cooler for cooling the gaseous first material by means of a refrigerant; and a second cooler for cooling the refrigerant, and the second cooler is used to cool the second material.

Description

Gas processing system and vessel containing same

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

[0002] A ship is a means of transportation that moves from a point of departure to a destination while storing a large amount of cargo. The shape, internal structure, and operating speed of the ship are determined by the type of cargo.

[0003] For example, if the cargo is a container, a cell guide for loading the container may be provided on the ship, and if the cargo is minerals, a storage space (hold) for loading the cargo in bulk may be provided on the ship.

[0004] Alternatively, if the cargo is a fluid substance, the vessel may be equipped with tanks for storing the cargo. In particular, if the fluid substance is a gaseous substance with a boiling point lower than room temperature, the tanks are designed to store the substance in a liquefied state.

[0005] For example, a tank may have a barrier and insulation structure to stably store a liquefied substance below its boiling point. The barrier / insulation structure of the tank may vary depending on the boiling point of the substance.

[0006] Materials transported in a liquefied state by ships include liquefied natural gas, liquefied petroleum gas, ammonia, carbon dioxide (CO2), hydrogen, etc. Ships are classified into liquefied natural gas carriers, liquefied petroleum gas carriers, and carbon dioxide carriers depending on the material being transported.

[0007] However, ships built specifically to transport specific liquefied substances are not suitable for transporting other substances with different boiling points. This is due to the different specifications of the equipment required to process the vaporized substances during transport, as well as the differences in the physical properties of the substances to be transported, such as their storage temperatures.

[0008] In other words, conventional liquid material carriers cannot change the material they transport, so there was a problem that enormous operating costs were inevitably incurred when transporting various types of materials.

[0009] The present invention was created to solve the problems of the prior art as described above, and to provide a gas processing system and a ship including the same that can secure versatility in loading and transporting liquefied substances by enabling loading and transporting liquefied petroleum gas, ammonia, etc., and carbon dioxide, etc.

[0010] A gas treatment system according to one aspect of the present invention includes a re-liquefaction unit for re-liquefying a gaseous substance discharged from a storage tank, wherein the storage tank stores at least one of a first substance and a second substance, and the re-liquefaction unit includes a first cooler for cooling the gaseous first substance with a refrigerant; and a second cooler for cooling the refrigerant, and the second substance is cooled using the second cooler.

[0011] Specifically, the refrigerant that exchanges heat with the first substance of the gas phase may include a second substance.

[0012] Specifically, the re-liquefaction unit may further include a first compressor for compressing a first gaseous substance; and a second compressor for compressing a refrigerant.

[0013] Specifically, the re-liquefaction unit may allow the refrigerant compressed in the second compressor and cooled in the second cooler to exchange heat with the first substance compressed in the first compressor in the first cooler in order to re-liquefy the first substance in the gas phase.

[0014] Specifically, the re-liquefaction unit may compress the second material in the gas phase by the second compressor and cool it in the second cooler to re-liquefy the second material.

[0015] Specifically, the re-liquefaction unit can block the flow of the first compressor when re-liquefying the second gaseous substance.

[0016] Specifically, the re-liquefaction unit may include a circulation path connecting the second compressor, the second cooler, and the first cooler in a closed form; a first re-liquefaction path connecting the storage tank, the first compressor, the first cooler, and the storage tank in series; and a second re-liquefaction path connecting the storage tank, the second compressor, the second cooler, and the storage tank in series.

[0017] Specifically, the second re-liquefaction path may be branched from the circulation path downstream of the second cooler.

[0018] Specifically, the storage tank can store a first material at a first pressure and a second material at a second pressure different from the first pressure.

[0019] Specifically, the first compressor may have a different operating pressure than the second compressor.

[0020] Specifically, the discharge pressure of the first compressor may be relatively higher than that of the second compressor.

[0021] Specifically, the internal pressure of the first reliquefaction flow path may be relatively higher than the internal pressure of the second reliquefaction flow path.

[0022] Specifically, the first compressor and the second compressor are provided in parallel, and the re-liquefaction unit may further include a third compressor provided in parallel with the first compressor and the second compressor to back up at least one of the first compressor and the second compressor.

[0023] Specifically, the first material may include carbon dioxide, and the second material may include at least one of ammonia and liquefied petroleum gas.

[0024] Specifically, it further includes a fuel tank for storing liquefied gas, and the re-liquefaction unit may further include a cold heat recovery device for exchanging heat between a gaseous substance and the liquefied gas.

[0025] Specifically, the cold heat recovery device is provided at a location upstream of the first cooler and upstream of the second cooler, and can cool a gaseous substance into liquefied gas and transmit the heated liquefied gas to a demand source.

[0026] A vessel according to one aspect of the present invention has the above gas treatment system.

[0027] The gas treatment system according to the present invention and the vessel including the same are arranged to enable universal loading of substances having different storage pressures, and can also ensure transportation stability by effectively liquefying substances when they have evaporated.

[0028] Figure 1 is a conceptual diagram of a ship according to a first embodiment of the present invention.

[0029] Figure 2 is a conceptual diagram of a gas processing system according to the first embodiment of the present invention.

[0030] Figure 3 is a conceptual diagram of a gas processing system according to the first embodiment of the present invention.

[0031] Figure 4 is a conceptual diagram of a gas processing system according to the first embodiment of the present invention.

[0032] Figure 5 is a conceptual diagram of a gas processing system according to a second embodiment of the present invention.

[0033] Figure 6 is a conceptual diagram of a gas processing system according to a second embodiment of the present invention.

[0034] Figure 7 is a conceptual diagram of a gas processing system according to a second embodiment of the present invention.

[0035] Figure 8 is a conceptual diagram of a gas processing system according to a third embodiment of the present invention.

[0036] Figure 9 is a conceptual diagram of a gas processing system according to a fourth embodiment of the present invention.

[0037] Figure 10 is a conceptual diagram of a gas processing system according to a fourth embodiment of the present invention.

[0038] Figure 11 is a conceptual diagram of a gas processing system according to a fourth embodiment of the present invention.

[0039] Figure 12 is a conceptual diagram of a gas processing system according to a fifth embodiment of the present invention.

[0040] Figure 13 is a conceptual diagram of a gas processing system according to a fifth embodiment of the present invention.

[0041] Figure 14 is a conceptual diagram of a gas processing system according to a fifth embodiment of the present invention.

[0042] The purpose, specific advantages, and novel features of the present invention will become more apparent from the following detailed description and preferred embodiments, taken in conjunction with the accompanying drawings. In this specification, when reference numerals are assigned to components in each drawing, it should be noted that, where possible, identical components are assigned the same reference numerals even if they appear in different drawings. Furthermore, in describing the present invention, if a detailed description of a related known technology is deemed to unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted.

[0043] The present invention, even if not illustrated in the drawings, can be provided without limitation in appropriate locations with pressure sensors (PT), temperature sensors (TT), flow sensors, block valves, control valves, pressure control valves, and the like. Furthermore, the measured values ​​from each sensor can be used in various ways without limitation in the operation of the configurations described below, and the opening degrees of the valves can be appropriately controlled.

[0044] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the attached drawings.

[0045] FIG. 1 is a conceptual diagram of a ship according to the present invention, and FIGS. 2 to 4 are conceptual diagrams of a gas processing system according to a first embodiment of the present invention.

[0046] First, referring to FIG. 1, the present invention includes a vessel (1) equipped with a gas processing system (10) described below through FIG. 2 and the like. In this case, the vessel (1) may be a carrier vessel loading materials, and the materials may include at least cargo among cargo and fuel. Furthermore, in the present invention, the vessel (1) is a concept that includes not only merchant ships but also FSRUs, FPSOs, bunkering vessels, and offshore plants.

[0047] The vessel (1) of the present invention includes a storage tank (CT) for storing materials. The storage tank (CT) may include at least one cargo tank provided within the hull. In this case, the cargo tank may be referred to as a cargo tank, etc., and a plurality of such tanks may be arranged along the longitudinal direction of the hull. Furthermore, the materials stored in the cargo tank may be handled as cargo to be delivered from the point of departure to the destination.

[0048] The substances stored in the CT may have a boiling point lower than room temperature. Therefore, at room temperature, these substances can naturally evaporate and transform into a gaseous substance. The gaseous substances generated within the CT are discharged outside the CT and processed, a process described in detail below.

[0049] In this specification, the substance may include at least one of a first substance and a second substance. The first substance and the second substance may have the same or different boiling points. Furthermore, the first substance and the second substance may have different storage pressures. For example, the first substance may include carbon dioxide, which must be stored at relatively high pressures (5 bar or higher) to suppress dry ice formation, and the second substance may include ammonia, liquefied petroleum gas, or the like, which can be stored at atmospheric pressure.

[0050] The vessel (1) of the present invention may be a vessel (1) that transports at least one of a first substance or a second substance as cargo. That is, the vessel (1) may be used to transport the first substance or the second substance, and further, may be used to transport both the first substance and the second substance simultaneously. Such a vessel (1) may be a carrier that simultaneously loads the first substance and the second substance.

[0051] For example, the vessel (1) may be used to operate while loading a first substance in a storage tank (CT), and after completing the transport of the first substance, the storage tank (CT) may be replaced with a second substance to transport the second substance. Alternatively, the vessel (1) may transport the first substance and the second substance simultaneously, for example, the first substance may be loaded in one storage tank (CT) and the second substance may be loaded in another storage tank (CT).

[0052] In this specification, the first and second substances may have different storage pressures during loading. For example, the loading pressure of the first substance may be higher than that of the second substance. As mentioned above, the first substance may be carbon dioxide, and carbon dioxide is preferably stored at high pressure (the first pressure) to suppress dry ice formation. On the other hand, the second substance, such as ammonia, may be stored at atmospheric pressure (the second pressure, which is relatively lower than the first pressure).

[0053] To this end, the storage tank (CT) of the present invention can be manufactured with the storage limit pressure of the first substance as the design pressure, and thus the storage tank (CT) can be manufactured with a design pressure that has sufficient margin compared to the storage limit pressure of the second substance. That is, the storage tank (CT) can be used to store the first substance at high pressure and, when necessary, to store the second substance at relatively low pressure, and the storage tank (CT) that stores the second substance can have relatively greater margin for confining the gaseous substance compared to the storage tank (CT) that stores the first substance.

[0054] A vessel (1) according to the present invention may further include a fuel tank (FT) in addition to a storage tank (CT). The fuel tank (FT) stores liquefied gas. The liquefied gas may be liquefied natural gas, etc., and may have a boiling point at least lower than that of the substance stored in the storage tank (CT).

[0055] Liquefied gas stored in a fuel tank (FT) must be heated to be delivered to the customer. Considering this, the low-temperature liquefied gas can be recovered as a material in a storage tank (CT). This will be described in detail in Example 2 below.

[0056] The vessel (1) can use the substance stored in the storage tank (CT) as fuel. The vessel (1) is equipped with a propulsion engine, a power generation engine, etc., and the propulsion engine etc. can generate energy by consuming the substance discharged from the storage tank (CT). Of course, the propulsion engine etc. can consume liquefied gas stored in the fuel tank (FT) in addition to the substance stored in the storage tank (CT).

[0057] A vessel (1) is provided with a gas treatment system (10). The gas treatment system (10) is described in detail below. However, in addition to the reliquefaction unit (100) described below, the gas treatment system (10) may further include a fuel supply unit (not shown).

[0058] The fuel supply unit processes at least one of the materials stored in the storage tank (CT) and the liquefied gas stored in the fuel tank (FT) and supplies them to the demand source. The demand source may be, but is not limited to, the propulsion engine described above. The fuel supply unit processes liquid or gaseous materials into a state suitable for the demand source. For example, the fuel supply unit may include a configuration that increases the temperature and pressure of the materials.

[0059] Hereinafter, the gas treatment system (10) provided in the vessel (1) of the present invention will be described with reference to FIG. 2, etc.

[0060] Referring to FIGS. 2 to 4, etc., the gas processing system (10) according to the first embodiment of the present invention includes a re-liquefaction unit (100). The gas processing system (10) may further include the fuel supply unit mentioned above in addition to the re-liquefaction unit (100), or may not include the fuel supply unit.

[0061] The reliquefaction unit (100) reliquefies a gaseous substance discharged from a storage tank (CT). A first substance or a second substance may be stored in the storage tank (CT), and both the first substance and the second substance may have a boiling point lower than room temperature.

[0062] Therefore, natural evaporation of substances is induced in the storage tank (CT) due to external heat penetration. The gaseous substances generated within the storage tank (CT) can be discharged outside the storage tank (CT) to relieve the pressure in the storage tank (CT). The substances discharged outside the storage tank (CT) can be delivered to the demand site for consumption, or can be re-liquefied and recovered by the re-liquefaction unit (100).

[0063] The re-liquefaction unit (100) may include a first compressor (110), a first cooler (120), a second compressor (210), a second cooler (220), etc. The first compressor (110) compresses a gaseous substance. For example, the first compressor (110) may compress a first gaseous substance. The first compressor (110) may compress the first substance to increase the boiling point of the first gaseous substance.

[0064] The operating pressure of the first compressor (110) may be 5 to 40 bar. This is based on the assumption that the first substance is carbon dioxide, and the discharge pressure of the first compressor (110) may vary depending on the composition and type of the first substance. However, as will be described again below, the discharge pressure of the first compressor (110) may be relatively higher than the discharge pressure of the second compressor (210).

[0065] The first compressor (110) may be configured in multiple stages, and may have a form in which a plurality of compression stages are configured in series. In addition, the first compressor (110) may be provided with a cooler (not shown) between the compression stages or downstream of the compression stages, and the cooler included in the first compressor (110) may be referred to as an intercooler or an aftercooler.

[0066] The first compressor (110) may be provided on the first re-liquefaction path (L10) through which the first gaseous substance is discharged from the storage tank (CT). The first re-liquefaction path (L10) connects the storage tank (CT) and the first compressor (110), and transfers the first gaseous substance compressed by the first compressor (110) to the first cooler (120). The first re-liquefaction path (L10) may connect the storage tank (CT), the first compressor (110), the first cooler (120), and the storage tank (CT) in series.

[0067] The first cooler (120) cools a gaseous substance using a refrigerant. The first cooler (120) may be provided downstream of the first compressor (110) and may cool the first gaseous substance compressed in the first compressor (110) by heat exchange with the refrigerant.

[0068] The first cooler (120) may have a path through which a first substance flows and a path through which a refrigerant flows. The path through which the first substance flows in the first cooler (120) may be arranged parallel to the first re-liquefaction path (L10), and the path through which the refrigerant flows in the first cooler (120) may be arranged parallel to the circulation path (L20) described below.

[0069] The first substance is compressed to a sufficient pressure in the first compressor (110) and then cooled (liquefied) by a refrigerant in the first cooler (120). Thereafter, the first substance can be transferred to the storage tank (CT) along the first re-liquefaction path (L10). However, the first substance may not be liquefied solely through heat exchange in the first cooler (120), and a pressure reducing valve (not shown) is provided downstream of the first cooler (120) to ensure that the first substance is sufficiently liquefied through pressure reduction.

[0070] A first substance in a gaseous state is generated in a storage tank (CT) that stores a first substance in a liquid state, and the first substance in a gaseous state discharged from the storage tank (CT) is transferred to a first re-liquefaction path (L10). The first re-liquefaction path (L10) sequentially connects a first compressor (110), a first cooler (120), and a pressure reducing valve from the storage tank (CT), so that the first substance in a gaseous state can be liquefied through compression, cooling, and pressure reducing. The liquefied first substance can be recovered to the storage tank (CT) through the first re-liquefaction path (L10) that connects the pressure reducing valve to the storage tank (CT).

[0071] The refrigerant used to cool the first material in the first cooler (120) may be any type of material without limitation. However, in the present embodiment, the refrigerant may include, for example, a second material.

[0072] When the storage tank (CT) is loaded with a second substance, at least a portion of the second substance can be delivered as a refrigerant before and after the first cooler (120). The refrigerant flowing path in the first cooler (120) forms part of a closed circulation path (L20), and the second substance can be filled on the circulation path (L20).

[0073] Afterwards, when the storage tank (CT) is changed to load the first substance, the first substance in the gaseous state discharged from the storage tank (CT) can be cooled using the second substance filled in the circulation path (L20) as a refrigerant.

[0074] Of course, even if the storage tanks (CT) provided on the ship (1) do not change the loading target from the second substance to the first substance, it is obvious that the second substance stored in some of the storage tanks (CT) can be used as a refrigerant for the first substance stored in other storage tanks (CT).

[0075] The second compressor (210) compresses the refrigerant used in the first cooler (120). The second compressor (210) may be provided as a multi-stage compressor identical to / similar to the first compressor (110) and may have a structure in which a cooler is provided.

[0076] The refrigerant compressed in the second compressor (210) may include a second substance as described above. In order to transfer the second substance to the second compressor (210), the second compressor (210) may be provided in parallel with the first compressor (110) downstream of the storage tank (CT). That is, a gaseous substance may be transferred from the storage tank (CT) to the first compressor (110) or the second compressor (210), and the first gaseous substance may be transferred to the first compressor (110) and the second gaseous substance may be transferred to the second compressor (210).

[0077] The second compressor (210) may have a different operating pressure than the first compressor (110). That is, the suction pressure of the first compressor (110) may be lower than that of the second compressor (210). In addition, the discharge pressure of the second compressor (210) may be relatively lower than that of the first compressor (110). For example, the operating pressure of the second compressor (210) may be 0 to 15 bar.

[0078] When the first substance is carbon dioxide and the second substance is ammonia, the storage tank (CT) storing the first substance is set to have a higher internal pressure than the storage tank (CT) storing the second substance. Then, the pressure of the first substance in the gas phase discharged from the storage tank (CT) is formed to be relatively higher than that of the second substance in the gas phase discharged from the storage tank (CT), so the suction pressure of the first compressor (110) is formed to be higher than the suction pressure of the second compressor (210).

[0079] In addition, the discharge pressure of the first compressor (110) may be set relatively higher than that of the second compressor (210). In this case, a pressure difference may be formed between the first substance and the refrigerant based on the first cooler (120). That is, the first substance in the gas phase that is compressed in the first compressor (110) and introduced into the first cooler (120) may have a higher pressure than the refrigerant (second substance in the gas phase) that is compressed in the second compressor (210) and introduced into the first cooler (120) (after being decompressed by a pressure reducing valve).

[0080] The second cooler (220) cools the refrigerant. The second cooler (220) is installed downstream of the second compressor (210) on the circulation path (L20) and can cool the refrigerant compressed in the second compressor (210) by exchanging heat with a cold source. At this time, the cold source can include fresh water, seawater, glycol water, etc. Since the refrigerant is sufficiently compressed and heated in the second compressor (210), the second cooler (220) can cool the compressed refrigerant even when using seawater at a zero temperature, etc.

[0081] The re-liquefaction unit (100) has a circulation path (L20) through which the refrigerant continuously circulates. The circulation path (L20) may have a closed loop, and may connect a second compressor (210), a second cooler (220), and a first cooler (120) in series. Accordingly, the refrigerant is compressed in the second compressor (210), cooled in the second cooler (220), and then heated while exchanging heat with a first substance in the first cooler (120), after which the refrigerant is transferred back to the second compressor (210).

[0082] Of course, a pressure reducing valve (not shown) similar to that described in the first re-liquefaction flow path (L10) may be provided on the circulation flow path (L20), and the pressure reducing valve may be provided between the second cooler (220) and the first cooler (120) to reduce the pressure of the refrigerant and cool the refrigerant.

[0083] The refrigerant cooled in the pressure reducing valve is used to cool the first substance in the first cooler (120), and after being heated in the first cooler (120), is transferred to the second compressor (210) and can be circulated back to the first cooler (120). The circulating flow path (L20) that implements this circulating flow can be filled with the refrigerant by injecting the second substance as needed.

[0084] The reliquefaction unit (100) can cool the second material using the second cooler (220). One or more storage tanks (CT) store at least one of the first material and the second material. The first material can be compressed in the first compressor (110), cooled by a refrigerant in the first cooler (120), and then recovered. On the other hand, the second material can be compressed in the second compressor (210), cooled by a cold source in the second cooler (220), and then recovered to the storage tank (CT).

[0085] Just as the first re-liquefaction flow path (L10) connects the storage tank (CT), the first compressor (110), the first cooler (120), and the storage tank (CT) in series, a second re-liquefaction flow path (L30) may be provided that connects the second compressor (210), the second cooler (220), and the storage tank (CT) in series from the storage tank (CT). However, the second re-liquefaction flow path (L30) may partially overlap with the circulation flow path (L20) through which the refrigerant circulates.

[0086] The refrigerant used to liquefy the first substance flowing along the first re-liquefaction path (L10) may flow along the circulation path (L20) that connects the second compressor (210), the second cooler (220), and the first cooler (120) in a closed manner. However, as mentioned above, since the refrigerant may be the second substance, the storage tank (CT) and the circulation path (L20) may be connected as needed.

[0087] The second re-liquefaction passage (L30) is configured to liquefy the second substance in a gaseous state discharged from the storage tank (CT) that stores the second substance, but is also configured to replenish refrigerant to the circulation passage (L20). That is, the second re-liquefaction passage (L30) extends from the storage tank (CT) and is connected to the circulation passage (L20), and can share the portions of the second compressor (210) and the second cooler (220) provided in the circulation passage (L20).

[0088] However, the second re-liquefaction path (L30) may be branched off from the circulation path (L20) downstream of the second cooler (220). Accordingly, when the second substance is used as a refrigerant, the second substance is delivered to the first cooler (120) along the circulation path (L20) downstream of the second cooler (220), whereas when the second substance is to be re-liquefied, the second substance may be recovered to the storage tank (CT) downstream of the second cooler (220). At this time, similar to what was described above, a pressure reducing valve (not shown) may be provided between the second cooler (220) and the storage tank (CT).

[0089] The internal pressure (5 to 40 bar) of the first reliquefaction channel (L10) is relatively high compared to the internal pressure (0 to 15 bar) of the second reliquefaction channel (L30). This is because the pressure at which the first substance is stored in the storage tank (CT) is higher than the pressure at which the second substance is stored in the storage tank (CT). As explained above, this may result in a pressure difference between the first substance and the second substance (refrigerant) in the first cooler (120).

[0090] Hereinafter, with reference to FIGS. 3 and 4, the case where the reliquefaction unit (100) reliquefies the first material and the case where the reliquefaction unit (100) reliquefies the second material will be described.

[0091] Figure 3 shows the fluid flow when the reliquefaction unit (100) reliquefies the first gaseous substance discharged from the storage tank (CT), and Figure 4 shows the fluid flow when the reliquefaction unit (100) reliquefies the second gaseous substance discharged from the storage tank (CT).

[0092] First, referring to FIG. 3, the storage tank (CT) stores the first substance at a first pressure, which is a relatively high pressure, and the first substance in the gaseous state generated within the storage tank (CT) is transferred from the storage tank (CT) to the first compressor (110) along the first re-liquefaction path (L10). At this time, the first substance is compressed in the first compressor (110) and then transferred to the first cooler (120), and after being cooled in the first cooler (120), can be recovered to the storage tank (CT).

[0093] On the other hand, a refrigerant (second substance) may flow in the second compressor (210). The refrigerant may be filled in a circulation path (L20) that connects the second compressor (210) and the second cooler (220) in a closed manner. The refrigerant is compressed in the second compressor (210), cooled in the second cooler (220), and then transferred to the first cooler (120).

[0094] The first cooler (120) cools the first substance by exchanging heat between the first substance in the gaseous state compressed by the first compressor (110) and the refrigerant cooled by the second cooler (220). That is, the re-liquefaction unit (100) allows the refrigerant compressed by the second compressor (210) and cooled by the second cooler (220) to exchange heat with the first substance compressed by the first compressor (110) in the first cooler (120) in order to re-liquefy the first substance in the gaseous state. The first substance cooled by the first cooler (120) can be returned to the storage tank (CT) via the pressure reducing valve.

[0095] On the other hand, referring to FIG. 4, the storage tank (CT) can store the second substance at a second pressure, which is a relatively low pressure. In this case, the second substance in the gaseous state discharged from the storage tank (CT) is transferred to the second compressor (210) along the second re-liquefaction path (L30). The second substance compressed in the second compressor (210) can be cooled by a cooling source in the second cooler (220) and returned to the storage tank (CT) via a pressure reducing valve.

[0096] That is, the re-liquefaction unit (100) can compress the second substance in the gas phase by using the second compressor (210) and cool it in the second cooler (220) to re-liquefy the second substance in the gas phase. In addition, the re-liquefaction unit (100) can block the flow of the first compressor (110) when re-liquefying the second substance in the gas phase.

[0097] Reliquefaction of both the first and second substances utilizes compression, heat exchange, and decompression. However, considering the cold source, liquefaction of the first substance may involve indirect heat exchange, while liquefaction of the second substance may involve direct heat exchange.

[0098] As described, in this embodiment, the second re-liquefaction path (L30) forms part of the refrigerant circulation path (L20) used to re-liquefy the first substance, and the refrigerant that cools the first substance includes the second substance. In this case, even if a single system is used, stable re-liquefaction can be ensured for the first and second substances, which have different storage pressures, etc.

[0099] For example, the present embodiment can be used as an ammonia carrier transporting a second substance, ammonia, and can be converted into a carbon dioxide carrier transporting a first substance, carbon dioxide, as needed. When the cargo is converted from ammonia to carbon dioxide, the vessel (1) of the present invention can utilize the ammonia re-liquefaction line and equipment for the re-liquefaction of carbon dioxide, and can also use ammonia as a refrigerant for carbon dioxide.

[0100] Therefore, the vessel (1) according to the present embodiment can cover all cases where the system operating pressure changes while providing one system (line, equipment, etc.), and thus can be used as a dual-purpose vessel for two substances with different transport pressures.

[0101] Figures 5 to 7 are conceptual diagrams of a gas processing system according to a second embodiment of the present invention. For reference, Figure 6 shows the fluid flow when the reliquefaction unit (100) reliquefies the first gaseous substance discharged from the storage tank (CT), and Figure 7 shows the fluid flow when the reliquefaction unit (100) reliquefies the second gaseous substance discharged from the storage tank (CT).

[0102] Referring to FIGS. 5 to 7, the gas treatment system (10) according to the second embodiment of the present invention can utilize the aforementioned fuel tank (FT). The fuel tank (FT) stores liquefied gas such as liquefied natural gas as fuel, and the liquefied gas discharged from the fuel tank (FT) is heated to be supplied to a demander.

[0103] However, the substance stored in the storage tank (CT) may have a lower boiling point than the liquefied gas stored in the fuel tank (FT), or the gaseous substance discharged from the storage tank (CT) may have a higher temperature than the liquefied gas discharged from the fuel tank (FT) and directed to the demand source.

[0104] The present embodiment can utilize the state of this liquefied gas for cooling a substance. For example, the present embodiment further includes a cold heat recovery device (300) that directly or indirectly exchanges heat between a gaseous substance and the liquefied gas.

[0105] The cold heat recovery unit (300) can exchange heat between a first substance in a gaseous state and a liquefied gas. To this end, the cold heat recovery unit (300) is installed on the first re-liquefaction path (L10). Specifically, the cold heat recovery unit (300) can be installed downstream of the first compressor (110) to cool the compressed first substance, and can be installed upstream of the first cooler (120) to pre-cool the first substance before liquefaction.

[0106] Alternatively, the cold heat recovery unit (300) may exchange heat between the refrigerant and the liquefied gas when the re-liquefaction unit (100) operates to liquefy the first substance. The cold heat recovery unit (300) may be installed on a circulation path (L20) through which the refrigerant circulates. For example, the cold heat recovery unit (300) may be installed downstream of the second compressor (210). The cold heat recovery unit (300) is arranged upstream of the second cooler (220) and downstream of the second compressor (210) to implement pre-cooling of the refrigerant.

[0107] Alternatively, the cold heat recovery unit (300) may be installed on the circulation path (L20) and positioned downstream of the second cooler (220). In this case, the refrigerant may be cooled in the second cooler (220) and then further cooled by liquefied gas in the cold heat recovery unit (300).

[0108] Of course, the cold heat recovery device (300) provided on at least one side of the upstream and downstream of the second cooler (220) in the circulation path (L20) can, in addition to exchanging heat between the refrigerant and the liquefied gas, also exchange heat between the second substance and the liquefied gas.

[0109] A second re-liquefaction path (L30) through which a second substance flows is provided to pass through a second compressor (210) and a second cooler (220), and a cold heat recovery device (300) provided upstream or downstream of the second cooler (220) can be placed on the second re-liquefaction path (L30).

[0110] Alternatively, the cold heat recovery device (300) may be provided to exchange heat between the cold heat source and the liquefied gas. That is, the cold heat recovery device (300) may be provided on a flow path through which the cold heat source flows in the second cooler (220), and for example, may be provided upstream of the second cooler (220) in the flow path of the cold heat source. Accordingly, the cold heat source cooled by the liquefied gas is introduced into the second cooler (220).

[0111] The cold heat recovery device (300) may be provided in one or more configurations as shown in FIG. 5, etc., and may be appropriately placed in the first re-liquefaction path (L10), the circulation path (L20), the second re-liquefaction path (L30), the cold heat source path, etc.

[0112] In addition, the inlets (A, B, C, D) and outlets (A', B', C', D') of the cold heat recovery device (300) illustrated in the drawing may be connected in series or parallel to each other. The liquefied gas discharged from the fuel tank (FT) is delivered to the demander. For example, the low-temperature liquefied gas may flow into the inlet (D) of one cold heat recovery device (300) and then be discharged through the outlet (D'), and then flow into the inlet (A) of another cold heat recovery device (300) and then be discharged through the outlet (A'). Alternatively, the low-temperature liquefied gas discharged from the fuel tank (FT) may be divided and supplied to the inlets (A, B) of two or more cold heat recovery devices (300) and discharged through the outlets (A', B') of the cold heat recovery devices (300). That is, a plurality of cold heat recovery devices (300) may be connected to each other based on at least one of series and parallel.

[0113] Referring to FIG. 6, when re-liquefying a first substance, the first substance moves along the first re-liquefaction path (L10), the refrigerant circulates along the circulation path (L20), and the cold heat source is transferred to the second cooler (220). In this case, all cold heat recovery devices (300) shown in the drawing can be utilized.

[0114] On the other hand, referring to FIG. 7, when re-liquefying the second substance, the second substance moves along the second re-liquefaction path (L30) and the flow before and after the first compressor (110) in the first re-liquefaction path (L10) is blocked. Therefore, among the cold heat recovery devices (300) shown in the drawing, at least those provided in the first re-liquefaction path (L10) may not be utilized.

[0115] Figure 8 is a conceptual diagram of a gas processing system according to a third embodiment of the present invention.

[0116] Referring to FIG. 8, the gas treatment system (10) according to the third embodiment of the present invention may have a first compressor (110) and a second compressor (210) arranged in parallel. Of course, there may not be a case where both the first compressor (110) and the second compressor (210) compress the same substance, but when examining a flow path through which a substance can flow regardless of the actual flow of the substance, it can be seen that the first compressor (110) and the second compressor (210) are arranged in parallel.

[0117] However, compressors may need to be shut down in the event of an unexpected situation, rendering the entire reliquefaction process inoperable. To prevent this, compressors must always be equipped with a backup system. Therefore, even if not shown in the drawings, a backup compressor may be included.

[0118] However, if backup compressors are provided for each of the first compressor (110) and the second compressor (210) based on Fig. 1, at least four compressors must be provided. This causes an increase in installation and operating costs.

[0119] In order to overcome this drawback, the present embodiment may be configured such that the first compressor (110) and the second compressor (210) can back up each other. That is, the first compressor (110) is provided in the first re-liquefaction flow path (L10), and further, a backup flow path (not shown) that connects the upstream and downstream of the first compressor (110) in the first re-liquefaction flow path (L10) but can pass through the second compressor (210) may be provided.

[0120] Also, conversely, a second compressor (210) is provided in the second re-liquefaction flow path (L30) or circulation flow path (L20), and a backup flow path (not shown) that connects the upstream and downstream of the second compressor (210) in the second re-liquefaction flow path (L30) or the like but can pass through the first compressor (110) may be provided.

[0121] Through this, the present embodiment can be arranged so that the first compressor (110) and the second compressor (210) can back up each other. When the re-liquefaction unit (100) re-liquefies the second substance, the second compressor (210) operates and the first compressor (110), which is not operating, can back up the second compressor (210). However, when the re-liquefaction unit (100) re-liquefies the first substance, the first compressor (110) compresses the first substance and the second compressor (210) compresses the refrigerant, so another compressor that is waiting for operation is additionally required.

[0122] Therefore, the present embodiment further includes a third compressor (400) provided in parallel with the first compressor (110) and the second compressor (210). The third compressor (400) can back up at least one of the first compressor (110) and the second compressor (210).

[0123] That is, when the re-liquefaction unit (100) re-liquefies the first substance, the first compressor (110) compresses the first substance, the second compressor (210) compresses the refrigerant, and the third compressor (400) is placed in an operation standby state. In addition, when the re-liquefaction unit (100) re-liquefies the second substance, the second compressor (210) compresses the second substance, and the first compressor (110) and the third compressor (400) can be placed in an operation standby state.

[0124] In order for the third compressor (400) to back up the first compressor (110) and the second compressor (210), backup paths may be provided in each of the first re-liquefaction path (L10) and the circulation path (L20), and the backup paths may be provided to pass through the third compressor (400). Accordingly, when a problem occurs in the first compressor (110) or the like during the re-liquefaction process of the first substance, the second compressor (210) can continuously compress the refrigerant and the third compressor (400) can back up the first compressor (110), thereby ensuring the re-liquefaction of the first substance.

[0125] Figures 9 to 11 are conceptual diagrams of a gas processing system according to a fourth embodiment of the present invention. For reference, Figure 10 shows the fluid flow when the reliquefaction unit (100) reliquefies the first gaseous substance discharged from the storage tank (CT), and Figure 11 shows the fluid flow when the reliquefaction unit (100) reliquefies the second gaseous substance discharged from the storage tank (CT).

[0126] Referring to FIGS. 9 to 11, the gas treatment system (10) according to the fourth embodiment of the present invention further includes a gas-liquid separator (230) and an intercooler (240) compared to the first embodiment.

[0127] The vapor-liquid separator (230) separates the refrigerant into vapor and liquid phases. The vapor-liquid separator (230) may be provided upstream of the second compressor (210). Only the vapor-phase refrigerant separated in the vapor-liquid separator (230) may flow into the second compressor (210), and the liquid-phase refrigerant separated in the vapor-liquid separator (230) may remain within the vapor-liquid separator (230). This prevents the liquid phase from flowing into the second compressor (210).

[0128] The purpose of this embodiment is to provide a gas-liquid separator (230) to prepare for the possibility that at least a portion of the refrigerant may exist in a liquid phase on the circulation path (L20). For example, when the refrigerant is a mixed refrigerant (MR) or liquefied petroleum gas, the gas-liquid separator (230) can block the liquid phase that may be included in the refrigerant from flowing into the second compressor (210) and transmit only the gaseous refrigerant to the second compressor (210).

[0129] As shown in Fig. 10, the vapor-liquid separator (230) is provided to separate the refrigerant into vapor and liquid phases. However, as shown in Fig. 11, the second substance may also pass through the vapor-liquid separator (230). In this case, the vapor-liquid separator (230) can separate the second substance into vapor and liquid phases, and only transmit the second substance in vapor form to the second compressor (210).

[0130] The intercooler (240) exchanges heat between refrigerants having different pressures and temperatures. The intercooler (240) may be provided downstream of the second cooler (220) and may exchange heat between refrigerants discharged from the second cooler (220) and separated into a first flow and a second flow.

[0131] For example, the intercooler (240) can exchange heat with a portion of the refrigerant cooled in the second cooler (220) and the remaining refrigerant cooled in the second cooler (220). At this time, a portion of the refrigerant passes through the intercooler (240) and is then transferred to the first cooler (120), and the remaining refrigerant is decompressed by a pressure reducing valve (not shown) before being introduced into the intercooler (240), thereby lowering its temperature. Therefore, the intercooler (240) can implement a function of cooling the refrigerant transferred from the second cooler (220) to the first cooler (120).

[0132] The remaining refrigerant, which is branched off downstream of the second cooler (220), depressurized by the depressurization valve, and heat-exchanged in the intercooler (240), can be delivered to the second compressor (210) along the branch flow path (L40). The remaining refrigerant discharged from the intercooler (240) can be delivered to the inlet or intermediate stage of the second compressor (210), and this can vary depending on the degree of depressurization of the depressurization valve.

[0133] The intercooler (240) may be provided in the form of a heat exchanger in which two streams flow continuously, or may be provided in the form of a drum in which at least one stream is temporarily stored inside.

[0134] The circulation path (L20) provided as described above allows the refrigerant to be separated into a vapor phase and a liquid phase in the vapor-liquid separator (230) and the vapor phase to be delivered to the second compressor (210), and the second cooler (220), the intercooler (240), and the first cooler (120) can be connected in series. In addition, a branch path (L40) is provided between the second cooler (220) and the intercooler (240) in the circulation path (L20), and a pressure reducing valve can be provided in the branch path (L40) upstream of the intercooler (240).

[0135] In addition, in the present embodiment, an intercooler (240) may be used to liquefy the second material, as shown in FIG. 11. That is, the second material compressed in the second compressor (210) may be cooled in the second cooler (220) and then divided into a portion of the second material and the remaining portion of the second material upstream of the intercooler (240). At this time, the remaining portion of the second material may be decompressed by a pressure reducing valve and used to cool a portion of the second material in the intercooler (240).

[0136] Figures 12 to 14 are conceptual diagrams of a gas processing system according to a fifth embodiment of the present invention. For reference, Figure 13 shows the fluid flow when the reliquefaction unit (100) reliquefies the first gaseous substance discharged from the storage tank (CT), and Figure 14 shows the fluid flow when the reliquefaction unit (100) reliquefies the second gaseous substance discharged from the storage tank (CT).

[0137] Referring to FIGS. 12 to 14, the gas processing system (10) according to the fifth embodiment of the present invention can provide an accumulator (250) and can add a cooling path (L21) in addition to the circulation path (L20) when compared to the fourth embodiment.

[0138] The accumulator (250) accumulates refrigerant. The accumulator (250) may have a configuration similar to the vapor-liquid separator (230) described in the fourth embodiment, and in addition to delivering the vapor-phase refrigerant to the second compressor (210), it may also perform the function of delivering the refrigerant to the first cooler (120).

[0139] In the previous embodiment, the refrigerant is arranged to sequentially circulate through the gas-liquid separator (230), the second compressor (210), the second cooler (220), the intercooler (240), and the first cooler (120) along the circulation path (L20), whereas in the present embodiment, the circulation path (L20) connects the gas-liquid separator (230), the second compressor (210), the second cooler (220), and the intercooler (240), and may not connect the first cooler (120). That is, the refrigerant flowing along the circulation path (L20) does not flow into the first cooler (120).

[0140] Instead, in the present embodiment, the refrigerant provided in the accumulator (250) is delivered to the first cooler (120), and a closed-circuit cooling path (L21) may be provided between the accumulator (250) and the first cooler (120). That is, the refrigerant is cooled through the second cooler (220) or the like along the circulation path (L20), and the cooled refrigerant may be stored in the accumulator (250). At this time, the accumulator (250) may deliver the low-temperature refrigerant to the first cooler (120). Therefore, in the present embodiment, the refrigerant cooled by the second cooler (220) and the refrigerant delivered to the first cooler (120) may be different from each other.

[0141] In addition, in this embodiment, the cooling of the refrigerant by the second cooler (220) and the delivery of the refrigerant to the first cooler (120) can be performed at different times. That is, the refrigerant can be cooled through the second cooler (220) and stored in the accumulator (250) at a low temperature, and then delivered to the first cooler (120) when necessary. Therefore, the accumulator (250) can be interpreted not only as a configuration that accumulates the flow rate of the refrigerant, but also as a configuration that accumulates the low-temperature energy of the refrigerant.

[0142] The present invention encompasses, in addition to the embodiments described above, combinations of the above embodiments and embodiments resulting from a combination of at least one embodiment and a known technology.

[0143] Although the present invention has been described in detail through specific examples, this is intended to specifically explain the present invention, and the present invention is not limited thereto, and it will be apparent that modifications and improvements can be made by those skilled in the art within the technical spirit of the present invention.

[0144] All simple modifications or changes of the present invention fall within the scope of the present invention, and the specific scope of protection of the present invention will be made clear by the appended claims.

Claims

1. Includes a re-liquefaction unit that re-liquefies gaseous substances discharged from a storage tank. The above storage tank stores at least one of the first material or the second material, The above re-liquefaction unit, A first cooler for cooling a first material in a gaseous state with a refrigerant containing the second material; and A second cooler for cooling the above refrigerant is included, A gas processing system that cools the second material using the second cooler.

2. In paragraph 1, The first substance contains carbon dioxide, A gas treatment system, wherein the second material comprises at least one of ammonia and liquefied petroleum gas.

3. In paragraph 1, the reliquefaction unit, a first compressor for compressing a first material of the gaseous phase; and A gas treatment system further comprising a second compressor for compressing refrigerant.

4. In the third paragraph, the reliquefaction unit, A gas treatment system in which a refrigerant compressed in the second compressor and cooled in the second cooler is heat-exchanged with a first substance compressed in the first compressor in the first cooler to re-liquefy a first substance of the gaseous phase.

5. In the third paragraph, the reliquefaction unit, A gas treatment system, wherein the second material is compressed by the second compressor and cooled in the second cooler to re-liquefy the second material in the gas phase.

6. In the third paragraph, the reliquefaction unit, A gas treatment system which blocks the flow of the first compressor when re-liquefying a second substance of the gaseous phase.

7. In the third paragraph, the reliquefaction unit, A circulation path connecting the second compressor, the second cooler, and the first cooler in a closed form; A first re-liquefaction path connecting the storage tank, the first compressor, the first cooler and the storage tank in series; and A gas processing system comprising a storage tank, a second compressor, a second cooler, and a second re-liquefaction path connecting the storage tank in series.

8. In paragraph 7, the second re-liquefaction path is, A gas treatment system branching from the circulation path downstream of the second cooler.

9. In the first paragraph, the storage tank, Store the first material at the first pressure, A gas processing system that stores a second material at a second pressure different from the first pressure.

10. In the third paragraph, the first compressor, A gas treatment system having a different operating pressure than the second compressor.

11. In the third paragraph, the first compressor, A gas treatment system having a relatively high discharge pressure compared to the second compressor.

12. In paragraph 8, A gas processing system, wherein the internal pressure of the first reliquefaction passage is relatively higher than the internal pressure of the second reliquefaction passage.

13. In the fourth paragraph, the first compressor and the second compressor, are arranged in parallel, The above re-liquefaction unit, A gas processing system further comprising a third compressor provided in parallel with the first compressor and the second compressor to back up at least one of the first compressor and the second compressor.

14. In paragraph 1, It further includes a fuel tank for storing liquefied gas, The re-liquefaction unit further includes a cold heat recovery unit that exchanges heat between a gaseous substance and a liquefied gas, and is provided at a location at least one of upstream of the first cooler and upstream of the second cooler, and is a gas processing system that cools a gaseous substance into a liquefied gas and delivers the heated liquefied gas to a demand source.

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