A liquid cargo handling system suitable for liquefied gas carriers carrying various types of goods

Abstract

This invention provides a liquid cargo handling system suitable for liquefied gas transport vessels carrying multiple types of cargo. The system includes a loading / unloading manifold assembly, at least one unloading manifold assembly, and at least two cargo tanks. Each loading / unloading manifold assembly includes at least two liquid phase pipes and at least two gas phase pipes. The loading / unloading manifold assembly includes two liquid phase mains and two gas phase mains. Any liquid phase pipe can be connected to any liquid phase main, and any gas phase pipe can be connected to any gas phase main. Each cargo tank has a cargo tank loading / unloading manifold assembly, which connects the cargo tank to any liquid phase main and any gas phase main. This invention employs two independent sets of liquid cargo loading / unloading pipe systems, enabling simultaneous loading and unloading of two types of cargo and allowing for free combination of any cargo to any cargo tank. It offers extremely high flexibility in loading liquefied gas cargo and solves the compatibility problem of multi-cargo transportation and the challenge of simultaneous loading and unloading of two types of cargo in existing technologies.

Description

Technical Field

[0001] This invention relates to the field of marine equipment technology, and in particular to a liquid cargo handling system suitable for liquefied gas transport ships carrying various types of cargo. Background Technology

[0002] As global trade deepens, maritime transport is no longer limited to traditional dry bulk cargo, containers, and crude oil; liquefied petroleum gas (LPG) has gradually become one of the main commodities in maritime trade. Simultaneously, with the diversification of the global economy, LPG carriers have expanded from initially transporting LNG energy to transporting chemical raw materials such as liquid ammonia, liquefied petroleum gas, liquefied propylene, and liquefied carbon dioxide. Since the demand for chemical raw materials is relatively lower than that for energy, the shipping industry has gradually developed a demand for multi-cargo LPG carriers. These vessels are suitable for transporting various LPG cargoes and can also transport two types of LPG cargoes simultaneously, giving shipowners more options in the LPG transport market and greater responsiveness to market changes. Furthermore, with increasing environmental requirements for ships, LPG carriers are increasingly using the cargo they are transporting as fuel to reduce pollutant emissions.

[0003] Liquefied gas (LPG) transportation involves numerous operational processes, including purging, inerting, precooling, loading, vapor treatment, and unloading. Currently, most LPG carriers primarily handle a single cargo, and their key equipment, the cargo handling system, can only process that single cargo. However, with the increasing demand for multi-cargo LPG carriers, single-cargo cargo handling systems will no longer meet the future development needs of LPG carriers.

[0004] However, for multi-cargo liquefied gas carriers, their liquid cargo handling systems need to face the following problems: compatibility issues of multi-cargo transportation, the challenge of loading and unloading two types of cargo simultaneously; compatibility issues of diverse storage facilities at liquefied gas receiving terminals; compatibility issues of handling vaporized gas from multi-cargo cargo, the question of how to handle vaporized gas in the liquid cargo tanks of different cargoes; and compatibility issues of liquid cargo transportation and ship fuel supply, etc. Summary of the Invention

[0005] In view of this, the present invention aims to propose a liquid cargo handling system applicable to multi-cargo liquefied gas transport ships, addressing the needs of multi-cargo liquefied gas transport ships to solve the compatibility problem of transporting multiple liquid cargoes and the problem of loading and unloading multiple liquid cargoes simultaneously.

[0006] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0007] A liquid cargo handling system applicable to liquefied gas transport vessels carrying various cargoes includes a loading / unloading manifold assembly, at least one unloading manifold assembly, and at least two liquid cargo tanks. The loading / unloading manifold assembly includes at least two liquid phase pipes and at least two gas phase pipes. The loading / unloading manifold assembly has four main pipes, including two liquid phase main pipes and two gas phase main pipes. Any two main pipes are connected in parallel. Any liquid phase pipe can be connected to any liquid phase main pipe, and any gas phase pipe can be connected to any gas phase main pipe. The liquid cargo tanks have cargo tank loading / unloading manifold assemblies, and the liquid cargo tanks can be connected to any liquid phase main pipe and any gas phase main pipe through the cargo tank loading / unloading manifold assemblies.

[0008] Furthermore, the loading and unloading pipe assembly includes, in sequence, a first liquid phase pipe, a first gas phase pipe, a second gas phase pipe, a second liquid phase pipe, a third liquid phase pipe, and a third gas phase pipe.

[0009] Furthermore, the cargo hold loading and unloading pipe assembly includes a liquid phase loading and unloading pipe and a gas phase loading and unloading pipe. One end of the liquid phase loading and unloading pipe can be connected to any liquid phase main pipe, and the other end can be connected to the liquid cargo tank. One end of the gas phase loading and unloading pipe can be connected to any gas phase main pipe, and the other end can be connected to the liquid cargo tank.

[0010] Furthermore, the liquid cargo tank is equipped with a top spray pipe and a bottom loading pipe. The liquid phase loading and unloading pipe can be connected to the top spray pipe and the bottom loading pipe, and the gas phase loading and unloading pipe is connected to the top of the liquid cargo tank. The liquid cargo tank is equipped with a liquid cargo pump and a self-pressurized unloading pipe. The suction inlet of the liquid cargo pump is located in the bottom space of the liquid cargo tank, and the outlet of the liquid cargo pump can be connected to the liquid phase loading and unloading pipe. One end of the self-pressurized unloading pipe is connected to the bottom space of the liquid cargo tank, and the other end is connected to the liquid phase loading and unloading pipe.

[0011] Furthermore, the system includes at least two sets of liquid cargo pressurization and heating components. Each liquid cargo pressurization and heating component includes a pressurization and heating pipe. One end of the pressurization and heating pipe can be connected to any liquid phase main pipe, and the other end can be connected to any liquid phase pipeline. A pressurization pump and a liquid cargo heat exchanger are sequentially arranged along the flow path of liquid cargo unloading.

[0012] Furthermore, the pressurization and heating pipe can be connected to any gas phase pipeline. The pressurization and heating pipe includes a bridge pipe, which is connected in parallel with the booster pump. Both the bridge pipe and the booster pump are connected in series with the liquid cargo heat exchanger.

[0013] Furthermore, the system includes a cryogenic assembly and a compression-reliquefaction assembly. The inlet side of the cryogenic assembly can be connected to the outlet pipe of the liquid cargo pump of any liquid cargo tank, and the outlet side of the cryogenic assembly can be connected to any liquid phase main pipe of the loading and unloading main pipe assembly. The inlet side of the compression-reliquefaction assembly can be connected to any gas phase main pipe of the loading and unloading main pipe assembly, and the outlet side of the compression-reliquefaction assembly can be connected to any liquid phase main pipe of the loading and unloading main pipe assembly.

[0014] Furthermore, the system includes a fuel assembly, which includes a deck tank DT. The deck tank DT can be connected to any liquid phase main of the loading and unloading main assembly, and can also be connected to any gas phase main of the loading and unloading main assembly. The deck tank DT is equipped with a fuel supply pump FP601 and a fuel supply pipe L609. The suction port of the fuel supply pump FP601 is located in the bottom space of the deck tank DT, and the outlet pipe L606 of the fuel supply pump FP601 is connected to the fuel supply pipe L609. The fuel supply pipe L609 can be connected to a clean fuel supply system.

[0015] Furthermore, the system includes a compression-reliquefaction assembly, which includes an evaporative gas compressor BC501, an evaporative gas liquefier HE501, a liquefied gas-liquid separator KOD501, and a liquefied gas-liquid separator KOD502 connected in sequence. The inlet of the evaporative gas compressor BC501 can be connected to any one of the gas phase mains of the loading and unloading mains, and the outlet of the liquefied gas-liquid separator KOD502 can be connected to any one of the liquid phase mains of the loading and unloading mains.

[0016] Furthermore, the fuel assembly includes a cryogenic fuel heat exchanger HE601, with its fuel inlet pipe L607 connected to the outlet pipe L606 of the fuel supply pump FP601, and its fuel outlet pipe L608 connected to the fuel liquid phase pipe; the liquefied gas gas-liquid separator KOD501 is provided with a discharge pipe L509, which is connected to the cold source inlet of the cryogenic fuel heat exchanger HE601 via an expansion valve EV52, and the cold source outlet of the cryogenic fuel heat exchanger HE601 is provided with a pipe L510, which is connected to the inlet pipe L503 of the evaporative gas compressor BC501 via the pipe L510.

[0017] Compared with existing technologies, the liquid cargo handling system for liquefied gas transport ships of various cargo types described in this invention has the following advantages:

[0018] The present invention provides a liquid cargo handling system applicable to liquefied gas transport ships carrying multiple types of cargo. First, it can realize the full-process liquid cargo handling operation of current liquefied gas transport ships. In addition, in response to the needs of multi-cargo liquefied gas transport ships, it adopts two independent sets of liquid cargo loading and unloading pipeline systems to realize the simultaneous loading and unloading of two types of cargo. It can also realize the free combination of any cargo to any cargo hold, which has extremely high flexibility in loading liquefied gas cargo and solves the compatibility problem of multi-cargo transportation and the problem of simultaneous loading and unloading of two types of cargo in the prior art.

[0019] Second, this application is also equipped with a liquid cargo pump and at least two sets of liquid cargo pressurization and heating components (including liquid cargo pressurization pump, liquid cargo heat exchanger and other equipment), which can realize fully cold unloading, semi-cold and semi-pressurized unloading, and fully pressurized unloading of liquid cargo, which can meet the needs of different liquefied gas storage devices at the liquid cargo terminal and solve the problem of diversified compatibility of liquefied gas cargo receiving terminal storage devices in the prior art.

[0020] Third, this application is also equipped with a cargo hold evaporation gas direct compression liquefaction device and an external refrigerated liquid cargo cryogenic cargo hold evaporation gas liquefaction device (i.e., compression reliquefaction component and cryogenic component) to meet the evaporation gas treatment needs of different liquefied gas cargoes. While reducing the risk of safety accidents, it also takes into account the economy of the system and solves the problem of multi-cargo evaporation gas treatment compatibility in the prior art, and the problem of how to treat evaporation gas in different cargo liquid cargo holds.

[0021] Fourth, this application is also equipped with a fuel assembly (including a deck tank DT) for storing liquefied gas cargo, and also for the storage and supply of fuel for clean fuel engines, thus combining the functions of a liquid cargo deck tank and a clean fuel tank, solving the compatibility problem between liquid cargo transportation and ship fuel supply in the prior art.

[0022] Fifth, this application combines the cryogenic process of fuel (or cargo) in the fuel assembly with the compression reliquefaction assembly. It utilizes the low-temperature gas-liquid mixture generated by depressurization evaporation in the compression reliquefaction assembly to cryogenically cool the cargo in the deck tank DT. On the one hand, it can achieve cooling and reliquefaction of the evaporated gas in the deck tank DT, which helps to reduce the number of refrigeration equipment and simplify the system structure. Moreover, it makes full use of the energy efficiency of the compression reliquefaction assembly, which helps to improve energy utilization efficiency and reduce system complexity and manufacturing costs. On the other hand, it enables the cargo cryogenically cooled by the fuel assembly to be sent to the liquid cargo tank storing the same cargo, and cools the evaporated gas generated in the corresponding liquid cargo tank. It can provide additional cooling support for the corresponding liquid cargo tank under certain specific conditions. Attached Figure Description

[0023] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. Furthermore, due to this application… Figure 1The overall system is quite complex. To facilitate clear display of system component numbers, this application includes appendices... Figure 1 Divided into three display areas, A, C, and D, by a red frame, each corresponding to the attached... Figure 2-4 In the attached diagram:

[0024] Figure 1 This is a schematic diagram of a liquid cargo handling system applicable to liquefied gas transport ships carrying various types of goods, as described in an embodiment of the present invention.

[0025] Figure 2 For the embodiments of the present invention in Figure 1 A schematic diagram of region A in the middle;

[0026] Figure 3 For the embodiments of the present invention in Figure 1 A schematic diagram of region B in the middle;

[0027] Figure 4 For the embodiments of the present invention in Figure 1 A schematic diagram of region C in the middle.

[0028] Explanation of reference numerals in the attached figures:

[0029] 11. Port side loading / unloading pipe assembly; 12. Starboard side loading / unloading pipe assembly; 2. Loading / unloading main pipe assembly; 21. Cargo hold loading / unloading pipe assembly; 31. First liquid cargo pressurization and heating assembly; 32. Second liquid cargo pressurization and heating assembly; 33. First port side pipe assembly; 34. First starboard side pipe assembly; 35. Second port side pipe assembly; 36. Second starboard side pipe assembly; 37. First bridge pipe; 38. Second bridge pipe; 4. Cryogenic assembly; 5. Compression reliquefaction assembly; 6. Fuel assembly. Detailed Implementation

[0030] The inventive concepts of this disclosure will be described below using terminology commonly used by those skilled in the art to communicate the essence of their work to others skilled in the art. However, these inventive concepts may be embodied in many different forms and should not be construed as limited to the embodiments described herein.

[0031] It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of this invention can be combined with each other. Furthermore, due to the relatively complex system structure and long individual pipelines of this application, relevant components are outlined with blue frames and given reference numerals to facilitate understanding of the solution in conjunction with the drawings. However, the relevant components (such as pipelines) are not limited to the area within the blue frames; it is recommended to understand the relevant components by their specific part numbers. Additionally, liquid phase pipelines in the drawings of this application are all solid black lines, and gas phase pipelines are all dashed black lines.

[0032] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0033] To address the needs of multi-cargo liquefied gas (LNG) carriers and to resolve the compatibility issues of transporting various liquid cargoes and the simultaneous loading and unloading of multiple liquid cargoes, this embodiment proposes a liquid cargo handling system suitable for multi-cargo LNG carriers, as shown in the attached figure. Figure 1-4 As shown, the system includes a loading / unloading manifold assembly 2, at least one loading / unloading manifold assembly, and at least two cargo tanks. The loading / unloading manifold assembly includes at least two liquid phase pipes and at least two gas phase pipes. The loading / unloading manifold assembly 2 has four manifolds, including two liquid phase manifolds and two gas phase manifolds. Any two manifolds are connected in parallel. Any liquid phase pipe can be connected to any liquid phase manifold, and any gas phase pipe can be connected to any gas phase manifold. The cargo tanks have cargo tank loading / unloading manifold 21, and the cargo tanks can be connected to any liquid phase manifold and any gas phase manifold through the cargo tank loading / unloading manifold 21.

[0034] This application, by setting up at least two liquid cargo tanks, a loading and unloading manifold group 2 consisting of "dual liquid phase manifolds + dual gas phase manifolds", and corresponding loading and unloading manifold groups, takes liquid phase media as an example. Each liquid phase pipeline can be connected to any liquid cargo tank through any liquid phase manifold, and the two liquid phase manifolds are connected in parallel. The same applies to gas phase media, which will not be elaborated further. Thus, when loading and unloading liquefied gas cargo, this application can simultaneously load and unload two types of liquefied gas cargo within the same time period (including simultaneous loading, simultaneous unloading, and one unloading and one loading, etc.). This not only improves the loading and unloading efficiency of the ship, but also prevents the mixing of different liquefied gas cargoes, ensures the purity of the liquefied gas cargo, and solves the compatibility problem of simultaneous transportation of different types of liquid cargo.

[0035] Meanwhile, for the two types of liquefied gas cargo being loaded and unloaded, it can be loaded and unloaded with any two cargo tanks, which facilitates the adjustment of cargo ballast on the ship. This makes the system applicable to fully refrigerated, semi-refrigerated and semi-pressurized, and fully pressurized liquefied gas carriers, with extremely high compatibility, meeting the current needs of multi-cargo liquefied gas carriers.

[0036] The loading and unloading pipe assembly includes three liquid phase pipes and three gas phase pipes. The assembly is arranged in the following order: first liquid phase pipe, first gas phase pipe, second gas phase pipe, second liquid phase pipe, third liquid phase pipe, and third gas phase pipe, forming a "liquid-gas-gas-liquid-liquid-gas" manifold arrangement. In reality, most terminal loading arms are arranged according to the international convention of "liquid-gas-liquid," but some terminals use a non-international convention arrangement, such as "gas-liquid-gas." Therefore, this application, based on the premise that the design requirements can be met by two liquid phase pipes and two gas phase pipes, adds an additional liquid phase pipe and one gas phase pipe, arranged in the "liquid-gas-gas-liquid-liquid-gas" pattern. This allows the loading and unloading pipe assembly to connect with both conventional international terminal loading arms and non-international convention loading arms, providing high flexibility and adaptability. Furthermore, with a total of six pipelines—three liquid phase pipelines and three gas phase pipelines—it is possible to ensure that the two liquid phase pipelines and the two gas phase pipelines can be used independently at the same time, thus ensuring the simultaneous loading and unloading of the two types of liquefied gas products.

[0037] Furthermore, in order to ensure the one-to-one correspondence between the loading and unloading pipe groups and the loading and unloading main pipe group 2, and to reduce the complexity of the pipeline structure, the newly added third liquid phase pipe is connected to the first liquid phase pipe, and the newly added third gas phase pipe is connected to the first gas phase pipe. Both the third liquid phase pipe and the third gas phase pipe are equipped with valve bodies. While satisfying the "liquid-gas-liquid" and "gas-liquid-gas" dock loading and unloading arm sequence, the correspondence between the four pipes of the loading and unloading pipe group and the four main pipes of the loading and unloading main pipe group 2 can still be maintained, and the pipeline structure can also be avoided from being too complicated.

[0038] Considering the existing layout of the actual dock and ships, the system includes two sets of unloading pipe assemblies, referred to as the port side loading and unloading pipe assembly 11 and the starboard side loading and unloading pipe assembly 12, so that the ship can dock with the dock loading and unloading device regardless of which side it is moored on.

[0039] For loading / unloading manifold group 2, please refer to the appendix. Figure 3 , 4 These are the liquid cargo loading and unloading main pipes L201 to L204, with L201 and L202 being the liquid phase main pipes and L203 and L204 being the gas phase main pipes.

[0040] Reference Appendix Figure 2 , 3The port side loading / unloading pipe assembly 11 includes port side liquefied gas cargo loading / unloading manifolds L101a~L106a. Pipes L101a, L102a, L103a, L104a, L105a, and L106a are arranged sequentially. Among them, pipes L101a, L104a, and L105a are liquid phase pipes, and pipes L102a, L103a, and L106a are gas phase pipes. Pipe L105a is connected to pipe L101a through valve V102a. Pipe L104a is connected to pipes L201 and L202 via valves V201a and V202a respectively; pipe L106a is connected to pipe L102a via valve V101a; pipe L102a is connected to pipes L203 and L204 via valves V205a and V207a respectively; and pipe L103a is connected to pipes L203 and L204 via valves V206a and V208a respectively.

[0041] Reference Appendix Figure 2 , 3 The starboard loading / unloading pipe assembly 12 includes starboard liquefied gas cargo loading / unloading manifolds L101b~L106b. Pipes L101b, L102b, L103b, L104b, L105b, and L106b are arranged sequentially. Among them, pipes L101b, L104b, and L105b are liquid phase pipes, and pipes L102b, L103b, and L106b are gas phase pipes. Pipe L105b is connected to pipe L101b through valve V102b. Pipe L104b is connected to pipes L201 and L202 via valves V201b and V202b respectively; pipe L106b is connected to pipe L102b via valve V101b; pipe L102b is connected to pipes L203 and L204 via valves V205b and V207b respectively; and pipe L103b is connected to pipes L203 and L204 via valves V206b and V208b respectively.

[0042] The cargo hold loading and unloading pipe assembly 21 includes a liquid phase loading and unloading pipe and a gas phase loading and unloading pipe. One end of the liquid phase loading and unloading pipe can be connected to any liquid phase main pipe, and the other end can be connected to the liquid cargo tank. One end of the gas phase loading and unloading pipe can be connected to any gas phase main pipe, and the other end can be connected to the liquid cargo tank.

[0043] For liquid cargo tanks, this application can set n, where n≥2, corresponding to the appendix. Figure 3 , 4The tanks are designated as CT1 (No. 1) and CTn (No. n). Each tank is equipped with a top spray pipe and a bottom loading pipe. The liquid phase loading / unloading pipe is connected to both the top and bottom spray pipes, while the gas phase loading / unloading pipe is connected to the top of the tank. Therefore, during liquid cargo loading, the top spray pipe and / or bottom loading pipe can be used depending on the actual situation. For example, the top spray pipe can be used to spray and utilize cryogenic liquefied gas to cool the tank and maintain its low temperature. The bottom loading pipe is located throughout the bottom of the tank and is used for loading liquid cargo under normal operating conditions.

[0044] Taking the No. 1 liquid cargo tank CT1 as an example, refer to the attached document. Figure 3 For the liquid phase pipeline, the liquid phase loading and unloading pipe includes pipes L208a, L209a, L210a, L211a, and L212a. Among them, one end of pipe L209a is connected to pipe L201, and the other end is connected to pipe L210a through valve V212a. One end of pipe L208a is connected to pipe L202, and the other end is connected to pipe L210a through valve V211a. Pipe L210a is divided into two paths entering the liquid cargo tank. One path is connected to pipe L212a at the top of the liquid cargo tank through valve V214a (pipe L212a is connected to the top spray pipe of the tank), and the other path is connected to pipe L211a through valve V213a (pipe L211a is connected to the bottom loading pipe of the tank). For the gas phase pipeline, the gas phase loading and unloading pipeline includes pipes L205a, L206a, and L207a. One end of pipe L206a is connected to pipe L203, and the other end is connected to pipe L207a via valve V210a. One end of pipe L205a is connected to pipe L204, and the other end is connected to pipe L207a via valve V209a. Pipe L207a is connected to the top space of the liquid cargo tank. Taking liquid cargo tank CTn (n#) as an example, refer to the appendix... Figure 4 Simply replace all instances of 'a' with 'b' in this paragraph; no further explanation is needed.

[0045] Based on the above detailed description, this application, by setting up two independent and parallel liquid phase mains L201 and L202, two independent gas phase mains L203 and L204, and their specific connections to the port side loading / unloading pipe group 11 and the starboard side loading / unloading pipe group 12, as well as their specific connections to each liquid cargo tank, can achieve connection or disconnection between any liquid phase pipeline in any loading / unloading pipe group and the liquid phase mains L201 and L202 through corresponding valve control. Similarly, the same applies to the gas phase pipelines. It can also achieve connection or disconnection between the liquid phase loading / unloading pipe of any liquid cargo tank and the liquid phase mains L201 and L202 through corresponding valve control. Similarly, the same applies to the gas phase pipelines. Thus, it can completely ensure that the loading and unloading of the two types of liquid cargoes can be carried out independently without the mixing of cargoes.

[0046] In addition, the liquid cargo tank is equipped with a liquid cargo pump and a self-pressurized unloading pipe. The suction inlet of the liquid cargo pump is located in the bottom space of the liquid cargo tank, and the outlet of the liquid cargo pump can be connected to the liquid phase loading and unloading pipe. One end of the self-pressurized unloading pipe is connected to the bottom space of the liquid cargo tank, and the other end is connected to the liquid phase loading and unloading pipe. This allows the liquid cargo to be transferred out of the tank when the pressure inside is low, and the tank pressure to be used to force the liquid cargo out through the self-pressurized unloading pipe when the pressure inside is high. Specifically, taking liquid cargo tank CT1 (No. 1) as an example, refer to the attached... Figure 3 The cargo tank is equipped with pipe L213a (i.e., self-pressurized unloading pipe). One end of pipe L213a is connected to the bottom space of the cargo tank, and the other end is connected to pipe L210a via valve V215a. The cargo tank is equipped with cargo pump CP1. The suction inlet of cargo pump CP1 is located in the bottom space of the cargo tank, and the outlet pipe L214a of cargo pump CP1 is connected to pipe L210a via valve V216a. Taking cargo tank CTn (n#) as an example, refer to the appendix... Figure 4 Simply replace all instances of 'a' with 'b' in this section, and replace CP1 with CPn in this section; further explanation is unnecessary.

[0047] For the unloading of liquefied gas (LPG) cargo after a liquefied gas carrier arrives at port, if the terminal's cargo receiving unit is a cryogenic, low-pressure, fully refrigerated storage tank, the system described above is used to transport the liquefied cargo from the cargo tank through the liquid phase main and liquid phase pipelines to the terminal unloading arm, where it is loaded into the corresponding terminal storage tank. However, if the terminal's cargo receiving unit is a medium-temperature, medium-pressure semi-refrigerated / semi-pressurized storage tank or a normal-temperature, high-pressure fully pressurized storage tank, it is necessary to pressurize or pressurize and heat the liquefied cargo to avoid the risk of unloading accidents.

[0048] Therefore, the system described in this application also includes at least two sets of liquid cargo pressurization and heating components. Each liquid cargo pressurization and heating component includes a pressurization and heating pipe. One end of the pressurization and heating pipe can be connected to any liquid phase main pipe, and the other end can be connected to any liquid phase pipeline. The pressurization and heating pipe is sequentially equipped with a pressurization pump and a liquid cargo heat exchanger along the flow path of liquid cargo unloading.

[0049] For cases where the terminal's liquid cargo receiving device is a medium-temperature, medium-pressure semi-cooled, semi-pressurized storage tank, there may be a certain pressure inside the storage tank. In this case, the liquid cargo in the liquid cargo tank can be pumped to the liquid phase loading and unloading pipe of the cargo tank loading and unloading pipe group 21, and then sent to the booster pump for secondary pressurization through the liquid phase main pipe of the loading and unloading main pipe group 2. At this time, the liquid cargo heat exchanger does not need to work. The liquid cargo after secondary pressurization is sent to the terminal loading and unloading arm through the liquid phase pipeline of the loading and unloading pipe group and loaded into the corresponding terminal storage tank.

[0050] For cases where the terminal's liquid cargo receiving device is a full-pressure storage tank with normal temperature and high pressure, the storage tank often cannot accept cryogenic liquid cargo. In this case, the liquid cargo in the liquid cargo tank can be transferred out by the liquid cargo pump, and enter the booster pump for secondary pressurization through the liquid phase loading and unloading pipe of the cargo tank loading and unloading pipe group 21 and the liquid phase main pipe of the loading and unloading main pipe group 2. The pressurized liquid cargo enters the liquid cargo heat exchanger, where the cryogenic liquid cargo is heated to normal temperature liquid cargo by normal temperature seawater. At this time, the liquid cargo, which has undergone two pressurizations, will not vaporize due to the temperature increase and can maintain a normal temperature and high pressure liquid state. Then, it is sent to the terminal loading and unloading arm through the liquid phase pipeline of the loading and unloading pipe group and loaded into the corresponding terminal storage tank.

[0051] Meanwhile, since this application sets up at least two sets of liquid cargo pressurization and heating components, it can safely unload two types of liquid cargo simultaneously, regardless of the type of terminal liquid cargo receiving device the ship is facing. That is, it can simultaneously perform direct unloading, pressurization unloading, and pressurization and heating unloading of two types of liquid cargo, or one type of liquid cargo can be unloaded using one of the following methods, while the other type of liquid cargo can be unloaded using another of the following methods. This application not only ensures the safety of liquid cargo unloading but also improves the efficiency of liquid cargo unloading.

[0052] The above only considers the impact caused by the terminal's liquid cargo receiving equipment. However, in reality, the different types of liquid cargo tanks on ships can also cause certain problems during liquid cargo unloading. For example, in the industry, fully refrigerated liquid cargo tanks such as Type A and Type B tanks have lower tank pressure. During the liquid cargo unloading process, as the liquid cargo is discharged, negative pressure can easily occur inside the liquid cargo tank, leading to damage to the liquid cargo tank.

[0053] In this case, for non-fully refrigerated storage tanks with high internal gas pressure, the gas generated by the evaporation of liquid cargo in the terminal liquid cargo receiving device can be directly sent to the gas phase pipeline of the loading and unloading pipe group, and then sent into the liquid cargo tank through the gas phase main pipe of the loading and unloading main pipe group 2 and the gas phase loading and unloading pipe of the cargo tank loading and unloading pipe group 21. This can compensate for the pressure loss caused by the unloading and unloading of liquid cargo, avoid the generation of negative pressure in the tank, and ensure the safety of the liquid cargo tank itself during the unloading process.

[0054] However, considering that when the liquid cargo receiving device at the terminal is a low-temperature, low-pressure, fully refrigerated storage tank, its internal gas pressure is low, making it difficult to return the liquid cargo vapors to the liquid cargo tank of the transport ship through the terminal liquid cargo receiving device. In response to this special situation, this application further improves the liquid cargo pressurization and heating component. Specifically, the pressurization and heating pipe can also be connected to any gas phase pipe. The pressurization and heating pipe includes a bridge pipe, which is connected in parallel with the booster pump. Both the bridge pipe and the booster pump are connected in series with the liquid cargo heat exchanger. That is, the bridge pipe can suspend the booster pump, so that the liquid cargo is sent to the liquid cargo heat exchanger without passing through the booster pump. Although direct unloading can be used for fully refrigerated storage tanks, in order to ensure the safety of the cargo tank itself, this application proposes an improved solution for the cargo pressurization and heating component. During cargo tank unloading, a portion of the cargo already sent to the liquid phase manifold of the loading and unloading manifold group 2 can be sent to the pressurization and heating pipe, and then through the bridge pipe into the cargo heat exchanger. The ambient temperature seawater is used to exchange heat with this portion of the cargo, raising its temperature. Since this portion of the cargo has not flowed through the pressurization pump, its own pressure is low. After heating, it vaporizes to generate evaporation gas. This evaporation gas is sent into the cargo tank through the pressurization and heating pipe, through the gas phase pipe of the loading and unloading manifold group, and the gas phase loading and unloading pipe of the cargo tank loading and unloading manifold group 21. By heating and evaporating a portion of the cargo in the cargo tank itself, the vapor is then returned to the cargo tank to compensate for the pressure loss caused by cargo unloading, avoid negative pressure in the tank, and ensure the safety of the cargo tank itself during the unloading process.

[0055] Since this application preferably provides two sets of unloading pipe assemblies (ship's port side loading / unloading pipe assembly 11 and ship's starboard side loading / unloading pipe assembly 12), for ease of description, this application refers to the two sets of liquid cargo pressurization and heating components as the first liquid cargo pressurization and heating assembly 31 and the second liquid cargo pressurization and heating assembly 32, respectively. The pressurization and heating pipes of the first liquid cargo pressurization and heating assembly 31 and the second liquid cargo pressurization and heating assembly 32 can be connected to any liquid phase pipe and any gas phase pipe of the ship's port side loading / unloading pipe assembly 11, and can also be connected to any liquid phase pipe and any gas phase pipe of the ship's starboard side loading / unloading pipe assembly 12. Among them, the pressurization and heating pipe of the first liquid cargo pressurization and heating assembly 31 is provided with a first bridge pipe 37 (corresponding to pipe L304a), and the pressurization and heating pipe of the second liquid cargo pressurization and heating assembly 32 is provided with a second bridge pipe 38 (corresponding to pipe L304b).

[0056] Specifically, the system includes a first port side pipe assembly 33, a first starboard side pipe assembly 34, a second port side pipe assembly 35, and a second starboard side pipe assembly 36. The discharge end of the first liquid cargo pressurization and heating component 31 can be connected to the ship's port side loading and unloading pipe assembly 11 (specifically, any one of its pipes, including liquid phase pipes and gas phase pipes) through the first port side pipe assembly 33, and can also be connected to the ship's starboard side loading and unloading pipe assembly 12 (specifically, any one of its pipes, including liquid phase pipes and gas phase pipes) through the first starboard side pipe assembly 34. The discharge end of the second liquid cargo pressurization and heating component 32 can be connected to the ship's port side loading and unloading pipe assembly 11 (specifically, any one of its pipes, including liquid phase pipes and gas phase pipes) through the second port side pipe assembly 35, and can also be connected to the ship's starboard side loading and unloading pipe assembly 12 (specifically, any one of its pipes, including liquid phase pipes and gas phase pipes) through the second starboard side pipe assembly 36.

[0057] A detailed description of any liquid cargo pressurization and heating assembly. Taking the first liquid cargo pressurization and heating assembly 31 as an example, refer to... Figure 3 The first liquid cargo pressurization and heating component 31 includes pressurization and heating pipes L301a to L304a. The inlet of the pressurization pump BP1 is divided into two paths: one path connects to pipe L201 via pipe L301a, with valve V301a installed on pipe L301a; the other path connects to pipe L202 via pipe L302a, with valve V302a installed on pipe L302a. Similarly, the outlet of the liquid cargo pressurization pump BP1 is divided into two paths: one path is pipe L303a, which connects to the liquid cargo inlet of the liquid cargo heat exchanger HE301; the other path... The pipeline is pipe L304a, which is the first bridge pipe 37 mentioned earlier. It is connected in parallel with the cargo booster pump BP1, with one end connected to the outlet of the cargo booster pump BP1 and the other end connected to the inlet of the cargo booster pump BP1. Correspondingly, pipe L303a can be connected to pipes L301a and L302a, and thus can be connected to pipes L201 and L202, thereby allowing the cargo booster pump BP1 to be suspended. At the same time, pipe L304a is equipped with valve V303a. The cargo heat exchanger HE301 is a conventional seawater-cargo heat exchanger, which will not be described in detail. Taking the second cargo booster and heating component 32 as an example, replace all 'a's in this paragraph with 'b's, and replace 'BP1's with 'BP2's. At the same time, its pipe L304b corresponds to the second bridge pipe 38 mentioned earlier, which will not be described in detail.

[0058] For the connection between any set of liquid cargo pressurization and heating components and the port side loading / unloading pipe assembly 11 and the starboard side loading / unloading pipe assembly 12 of the ship, taking the first liquid cargo pressurization and heating component 31, the first port side pipe assembly 33, and the first starboard side pipe assembly 34 as examples, refer to Figure 2 , 3The cargo outlet of the liquid cargo heat exchanger HE301 is also divided into two paths: one is pipe L305a connected to the first port side pipe group 33, and the other is pipe L310a connected to the first starboard side pipe group 34. The first port side pipe group 33 includes pipes L306a to L309a connected in parallel. Each of pipes L306a to L309a has one end connected to pipe L305a, but the other end of pipe L306a is connected to pipe L101a via valve V304a. The other end of pipe L307a is connected to pipe L102a via valve V305a, and the other end of pipe L308a is connected to pipe L101a via valve V306a. L103a, the other end of pipe L309a is connected to pipe L104a via valve V307a; the first starboard pipe group 34 includes pipes L311a~L314a connected in parallel, wherein one end of each of pipes L311a~L314a is connected to pipe L310a, but the other end of pipe L311a is connected to pipe L101b via valve V308a, the other end of pipe L312a is connected to pipe L102b via valve V309a, the other end of pipe L313a is connected to pipe L103b via valve V310a, and the other end of pipe L314a is connected to L104b via valve V311a. Taking the second liquid cargo pressurization and heating assembly 32, the second port side pipe group 35, and the second starboard side pipe group 36 as examples, all 'a's in this paragraph can be replaced with 'b's, which will not be elaborated further.

[0059] During the storage of liquid cargo, the liquid cargo tanks inevitably absorb heat from the environment, leading to vaporization and evaporation. This causes an increase in temperature and pressure within the tanks, necessitating timely treatment of the vaporized gas to prevent safety accidents. Furthermore, considering the diverse types of cargo stored on the transport ship—including easily compressible and liquefiable substances like ammonia and LPG, as well as incompressible and non-compressible substances like carbon dioxide and ethylene—the system includes a cryogenic assembly 4 and a compression-reliquefaction assembly 5. The inlet of the cryogenic assembly 4 can be connected to the outlet pipe of any liquid cargo tank's pump, and the outlet of the cryogenic assembly 4 can be connected to any liquid phase main pipe of the loading / unloading main assembly 2. This allows incompressible and non-compressible cargo to be pumped to the cryogenic assembly 4 for cooling before being fed into the corresponding liquid cargo pump via the liquid phase main pipe of the loading / unloading main assembly 2 and the liquid phase loading / unloading pipe of the cargo tank loading / unloading assembly 21. The inlet of the compression-reliquefaction assembly 5 can... The outlet side of the compression-reliquefaction assembly 5 can be connected to any one of the gas phase mains of the loading and unloading mains group 2. For goods that are easy to compress and liquefy, the evaporated gas in the liquid cargo tank is compressed and reliquefied through the gas phase loading and unloading pipe of the cargo hold loading and unloading pipe group 21 and the gas phase main of the loading and unloading mains group 2, forming a low temperature and low pressure liquid. Then, it is sent to the corresponding liquid cargo pump through the liquid phase main of the loading and unloading mains group 2 and the liquid phase loading and unloading pipe of the cargo hold loading and unloading pipe group 21.

[0060] For cryogenic component 4, refer to Figure 4 This includes a refrigeration unit RU401, a cryogenic heat exchanger for liquid cargo HE401, and pipes L402~L406. One end of pipe L402 can be connected to the outlet pipe of the liquid cargo pump of each liquid cargo tank via a branch pipe assembly, and the other end is connected to the cargo inlet of the cryogenic heat exchanger HE401. The branch pipe assembly includes multiple parallel branch pipes. One end of each branch pipe is connected to the outlet pipe of the corresponding liquid cargo tank's liquid cargo pump, and the other end is connected to pipe L402. Each branch pipe is equipped with a valve body, for example, attached... Figure 3 , 4 The branch pipes L401a and L401b and their corresponding valves V401a and V401b are shown in the diagram. Since this application only shows two cargo tanks and two branch pipes, if more cargo tanks exist, the corresponding branch pipes can be added. The cargo outlet of the cryogenic heat exchanger HE401 is divided into two paths: one is pipe L403 connected to the liquid phase main pipe L202 via valve V402, and the other is pipe L404 connected to the liquid phase main pipe L201 via valve V403. The refrigerant of the refrigeration unit RU401 is connected to the cryogenic heat exchanger HE401 via pipes L405 and L406 (one inlet and one outlet).

[0061] For compression-reliquefaction component 5, refer to Figure 4 The system includes, in sequence, an evaporative gas compressor BC501, an evaporative gas liquefaction unit HE501, an LPG gas-liquid separator KOD501, and an LPG gas-liquid separator KOD502. The inlet of the evaporative gas compressor BC501 can be connected to any one of the gas phase mains of the loading / unloading main assembly 2, and the outlet of the LPG gas-liquid separator KOD502 can be connected to any one of the liquid phase mains of the loading / unloading main assembly 2. The evaporative gas liquefaction unit HE501 is a common seawater-cargo heat exchanger, which uses seawater to exchange heat, cool, and liquefy the cargo.

[0062] Specifically, on the inlet side of the compression reliquefaction assembly 5, the inlet pipe L503 of the evaporative gas compressor BC501 is divided into two paths: one path connects to pipe L501, which is connected to the gas phase main pipe L204 via valve V501; the other path connects to pipe L502, which is connected to the gas phase main pipe L203 via valve V502. On the outlet side of the compression reliquefaction assembly 5, the outlet of the liquefied gas-liquid separator KOD502 is divided into two paths: one path is pipe L507, which is connected to the liquid phase main pipe L201 via valve V504; the other path is pipe L508, which is connected to the liquid phase main pipe L202 via valve V503.

[0063] Regarding the connection between the inlet and outlet sides of the compression-reliquefaction assembly 5, the outlet pipe L504 of the evaporative gas compressor BC501 is connected to the product inlet of the evaporative gas liquefier HE501. The product outlet of the evaporative gas liquefier HE501 is divided into two paths: one is pipe L505, which is directly connected to the inlet of the LPG gas-liquid separator KOD501; the other is pipe L512, which is connected to pipe L507 via valve V507. The outlet pipe L506 of the LPG gas-liquid separator KOD501 is connected to the inlet of the LPG gas-liquid separator KOD502 via expansion valve EV51. Furthermore, the LPG gas-liquid separator KOD502 has a gas phase outlet pipe L511, which is connected to the inlet pipe L503 of the evaporative gas compressor BC501 via valve V505.

[0064] Therefore, the cryogenic assembly 4 and the compression-reliquefaction assembly 5 provided in this application can compress, cool, and reliquefy the evaporating gases generated by easily compressible and liquefiable substances such as ammonia and LPG. For evaporating gases generated by substances that are not easily compressible and liquefiable, such as carbon dioxide and ethylene, the cryogenic assembly 4 can cryogenically cool the evaporating gases. Then, the evaporating gases are sent into the liquid cargo tank through the liquid phase loading and unloading pipe of the cargo tank loading and unloading pipe assembly 21. Preferably, the cryogenically cooled liquid cargo is sprayed into the liquid cargo tank through the tank top spray pipe to cool the evaporating gases inside the tank, thus fully realizing the reliquefaction of the evaporating gases inside the tank. This application not only solves the problem of compatibility in handling evaporating gases from multiple cargoes, but also solves the problem of how to handle evaporating gases from different types of cargoes in a timely and effective manner. It is applicable to the storage and long-distance transportation of different types of liquid cargoes, can meet the needs of different liquid cargoes, ensure that the liquid cargo tank maintains a stable internal temperature and pressure, avoid safety accidents, and reduce the actual ship operating costs.

[0065] For existing liquefied gas carriers, fuel-type liquid cargoes are often used, processed, and supplied to the engine for combustion to maintain the ship's power. Therefore, the system includes a fuel assembly 6, which includes a deck tank DT for storing the fuel-type liquid cargo required for the ship's power. The deck tank DT can be connected to any liquid phase main and any gas phase main of the loading / unloading main assembly 2. The deck tank DT can also be connected to a clean fuel supply system to supply fuel to the ship's power system. Thus, like other cargo tanks, the deck tank DT can perform loading and unloading. It should be noted that since this application does not limit the types of liquid cargoes stored in the cargo tanks, individual cargo tanks can also store the same type of fuel-type liquid cargo.

[0066] The piping layout of the deck tank (DT) is similar to that of the cargo tank structure and the functions of the corresponding structures. The deck tank (DT) is equipped with a fuel loading and unloading pipe assembly, which includes a liquid fuel pipe and a gas fuel pipe. One end of the liquid fuel pipe can be connected to any liquid phase main pipe, and the other end can be connected to the deck tank (DT). One end of the gas fuel pipe can be connected to any gas phase main pipe, and the other end can be connected to the deck tank (DT). The interior of the deck tank (DT) is equipped with a top spray pipe and a bottom loading pipe. The liquid fuel pipe can be connected to the top spray pipe and the bottom loading pipe, and the gas fuel pipe is connected to the top of the deck tank (DT). Specifically, the fuel liquid phase pipe includes pipes L601 to L605. One end of pipe L601 is connected to pipe L603, and the other end is connected to pipe L202 through valve V601. One end of pipe L602 is connected to pipe L603, and the other end is connected to pipe L201 through valve V602. Pipe L603 is divided into two paths that enter the deck tank DT. One path is connected to pipe L604 at the top of the deck tank DT through valve V603 (pipe L604 is connected to the top spray pipe of the deck tank DT), and the other path is connected to pipe L605 through valve V604 (pipe L605 is connected to the bottom loading pipe of the deck tank DT). The fuel vapor phase pipeline includes pipes L610, L611, and L612. One end of pipe L611 is connected to pipe L610, and the other end is connected to pipe L203 via valve V607. One end of pipe L612 is connected to pipe L610, and the other end is connected to pipe L204 via valve V608. Pipe L610 connects to the top space of the deck tank DT. The deck tank DT is also equipped with a fuel supply pump FP601 and a fuel supply pipe L609. The suction inlet of fuel supply pump FP601 is located in the bottom space of the deck tank DT, and the outlet pipe L606 of fuel supply pump FP601 is connected to fuel supply pipe L609. Fuel supply pipe L609 can be connected to a clean fuel supply system to deliver fuel from the deck tank DT to the clean fuel supply system. Correspondingly, valve V607 is installed on fuel supply pipe L609.

[0067] For the deck tank DT, it will also absorb heat from the environment and form evaporation gas inside the deck tank DT. If it stores fuel-type liquid cargo that is easy to compress and liquefy, consistent with the cooperation between the liquid cargo tank and the compression and reliquefaction assembly 5 mentioned above, it can send the evaporation gas generated by the deck tank DT to the compression and reliquefaction assembly 5 for compression, cooling and reliquefaction, and then send it back to the deck tank DT.

[0068] Regardless of whether the tank DT stores easily compressible and liquefied fuels, in order to completely prevent the mixing of fuels with other goods, this application further improves the fuel assembly 6. Specifically, the fuel assembly 6 includes a cryogenic fuel heat exchanger HE601. The fuel inlet pipe L607 of the cryogenic fuel heat exchanger HE601 is connected to the outlet pipe L606 of the fuel supply pump FP601, and the fuel outlet pipe L608 of the cryogenic fuel heat exchanger HE601 is connected to the fuel liquid phase pipe (preferably, the fuel outlet pipe L608 is connected to pipe L603). Correspondingly, valve V605 is installed on the fuel inlet pipe L607, and valve V606 is installed on the fuel outlet pipe L608. Therefore, when the pressure of the evaporating gas in the deck tank DT rises to the design value, the fuel supply pump FP601 can be started to send a portion of the fuel to the fuel cryogenic heat exchanger HE601 for heat exchange and cooling (i.e., cryogenic). The cryogenic fuel is sent to the top spray pipe of the deck tank DT through the fuel liquid phase pipe, and sprayed down from the top space inside the deck tank DT. During the spraying and falling process, the cryogenic fuel comes into contact with the evaporating gas inside the deck tank DT for heat exchange, which cools down and liquefies the evaporating gas, realizing the re-liquefaction of the evaporating gas inside the deck tank DT, and ultimately reducing the temperature and pressure inside the deck tank DT.

[0069] As for the cold source of the fuel cryogenic heat exchanger HE601, it can be supplied by an independent refrigeration device; however, in order to reduce the number of related equipment, simplify the system structure, and improve energy utilization efficiency, this application combines the fuel cryogenic heat exchanger HE601 with the compression reliquefaction assembly 5 mentioned above. Specifically, the liquefied gas gas-liquid separator KOD501 is equipped with a discharge pipe L509, which is connected to the cold source inlet of the fuel cryogenic heat exchanger HE601 through an expansion valve EV52. The cold source outlet of the fuel cryogenic heat exchanger HE601 is equipped with a pipe L510, which is connected to the inlet pipe L503 of the evaporative gas compressor BC501 through the pipe L510. Correspondingly, the pipe L510 is equipped with a valve V506. Therefore, for the cold source supply of the fuel cryogenic heat exchanger HE601, the high-pressure room-temperature liquid cargo in the LPG gas-liquid separator KOD501 (this liquid cargo is formed into a high-pressure room-temperature liquid cargo after passing through the evaporator compressor BC501 and the evaporator liquefaction unit HE501) is used. After the pressure is reduced by the expansion valve EV52, the pressure decreases and flash evaporation occurs, and part of it is vaporized to form a low-temperature gas-liquid mixture. Then, the low-temperature gas-liquid mixture is sent to the fuel cryogenic heat exchanger HE601 as a cold source to exchange heat with the fuel delivered by the deck tank DT (corresponding to the deep cooling of the fuel mentioned above). After heat exchange, the low-pressure low-temperature gas-liquid mixture absorbs heat and completely vaporizes into a gaseous cargo. The gaseous cargo is sent to the evaporator compressor BC501 through the cold source outlet of the fuel cryogenic heat exchanger HE601 and pipe L510, and re-participates in the compression and reliquefaction process provided by the compression and reliquefaction assembly 5. Therefore, this application organically combines the deep cooling of fuel with the compression reliquefaction component 5, which not only helps to reduce the number of refrigeration equipment and simplify the system structure, but also makes full use of the energy efficiency of the compression reliquefaction component 5, thus helping to improve energy utilization efficiency.

[0070] This application, by setting up fuel assembly 6, allows for the filling of deck tank DT with fuel liquid through the liquid phase manifold of loading and unloading manifold group 2 during the loading of liquid cargo at the dock. Deck tank DT can be regarded as a liquid cargo tank, which can store and transport liquid cargo, and also as a fuel tank, which can send fuel to the clean fuel supply system to supply fuel to the ship's power system. In addition, if the cargo stored in individual liquid cargo tanks is the same as the cargo stored in deck tank DT, since the cargo in deck tank DT can be cryogenically cooled by fuel cryogenic heat exchanger HE601, this cryogenically cooled cargo can also be used as a cooling medium for the corresponding liquid cargo tank. It can be sent to the corresponding liquid phase manifold through pipes L608 and L603, and then sent to the corresponding liquid cargo tank for cooling. This allows fuel assembly 6 to provide additional cooling support for the corresponding liquid cargo tank under certain specific conditions.

[0071] Based on this, the liquid cargo handling system proposed in this application is applicable to liquefied gas transport ships carrying multiple types of cargo. First, it can realize the full-process liquid cargo handling operation of current liquefied gas transport ships. In addition, in response to the needs of multi-cargo liquefied gas transport ships, it adopts two independent sets of liquid cargo loading and unloading pipeline systems to realize the simultaneous loading and unloading of two types of cargo. It can also realize the free combination of any cargo to any cargo hold, which has extremely high flexibility in loading liquefied gas cargo. It solves the compatibility problem of multi-cargo transportation and the problem of simultaneous loading and unloading of two types of cargo in the prior art.

[0072] Second, this application is also equipped with a liquid cargo pump and at least two sets of liquid cargo pressurization and heating components (including liquid cargo pressurization pump, liquid cargo heat exchanger and other equipment), which can realize fully cold unloading, semi-cold and semi-pressurized unloading, and fully pressurized unloading of liquid cargo, which can meet the needs of different liquefied gas storage devices at the liquid cargo terminal and solve the problem of diversified compatibility of liquefied gas cargo receiving terminal storage devices in the prior art.

[0073] Third, this application is also equipped with a cargo hold evaporation gas direct compression liquefaction device and an external refrigerated liquid cargo cryogenic cargo hold evaporation gas liquefaction device (i.e., compression reliquefaction component 5 and cryogenic component 4) to meet the evaporation gas treatment needs of different liquefied gas cargoes. While reducing the risk of safety accidents, it also takes into account the economy of the system and solves the problem of multi-cargo evaporation gas treatment compatibility in the prior art, and the problem of how to treat evaporation gas in different cargo liquid cargo holds.

[0074] Fourth, this application is also equipped with fuel assembly 6 (including deck tank DT) for storing liquefied gas cargo, and also for fuel storage and supply for clean fuel engines, combining the functions of liquid cargo deck tank and clean fuel tank, thus solving the compatibility problem between liquid cargo transportation and ship fuel supply in the prior art.

[0075] Fifth, this application combines the cryogenic process of the fuel (or cargo) in the fuel assembly 6 with the compression reliquefaction assembly 5. The low-temperature gas-liquid mixture generated by depressurization evaporation in the compression reliquefaction assembly 5 is used to cryogenically cool the cargo in the deck tank DT. On the one hand, it can achieve the cooling and reliquefaction of the evaporated gas in the deck tank DT, which helps to reduce the number of refrigeration equipment and simplify the system structure. Moreover, it makes full use of the energy efficiency of the compression reliquefaction assembly 5, which helps to improve energy utilization efficiency and reduce system complexity and manufacturing costs. On the other hand, it enables the cargo cryogenically cooled by the fuel assembly 6 to be sent to the liquid cargo tank storing the same cargo, and to cool the evaporated gas generated in the corresponding liquid cargo tank. Under certain specific circumstances, it can provide additional cooling support for the corresponding liquid cargo tank.

[0076] The technical solutions in the embodiments of the present invention will now be clearly and completely described with reference to the accompanying drawings. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0077] Example 1

[0078] like Figure 1-4 As shown, this embodiment provides a detailed description of the processing operations in different processes based on the system, so as to facilitate a full understanding of the technical solution of this application.

[0079] 1. Before loading liquid cargo tanks, all tanks need to be dried and inerted. This process is completed using liquid nitrogen supplied by the terminal. Depending on the ship's berthing position, either the port side loading / unloading pipe assembly 11 or the starboard side loading / unloading pipe assembly 12 is selected as the shore access interface. Here, we assume the port side loading / unloading pipe assembly 11 is used. The shore-based liquid nitrogen delivery pipe connects to the liquid phase pipeline L101a. Valve V304a in the first port side pipe assembly 33 is opened, allowing liquid nitrogen to enter the liquid cargo heat exchanger HE301. At this time, seawater is allowed to circulate, heating and vaporizing the liquid nitrogen to form ambient temperature nitrogen gas. Valves V303a and V302a in the first liquid cargo pressurization and heating assembly 31 are opened, allowing nitrogen gas to enter the liquid phase main pipe L202. Valves V211a, V211b, V213a, and V213b are then opened. Nitrogen gas is introduced into cargo tanks CT1 and CTn, and deck tank DT via valves V601 and V604. Simultaneously, valves V209a, V209b, V608, and V207a are opened, causing air in cargo tanks CT1, CTn, and DT to be purged by the nitrogen gas. The nitrogen gas then flows through the gas phase manifold L204 to the gas phase pipeline L102a of the port side loading / unloading pipeline assembly 11. L102a is connected to the shore-based venting device to release the air and nitrogen gas. Liquid nitrogen is continuously introduced until the dew point temperature in cargo tanks CT1, CTn, and DT reaches the required level, completing the purging and drying operation of these tanks. If the shore station provides nitrogen gas instead of liquid nitrogen, then the liquid nitrogen vaporization process via the cargo heat exchanger HE301 is unnecessary. Instead, keep valve V304a closed, eliminating the need to connect the cargo heat exchanger HE301. Open valve V202a on the liquid phase pipeline L101a, and continue with the other operating procedures. Allow the nitrogen gas to directly enter the cargo tank through L202 to complete the cargo tank purging and drying. Simultaneously, purging and inerting all pipelines required for subsequent operations requires switching the corresponding valves and replacing the onshore connector pipelines.

[0080] 2. After purging and drying, the loaded liquid cargo needs to be used to purge and pre-cool the pipelines and liquid cargo tanks. For the sake of explaining this implementation plan, it is assumed that the ship carries liquid cargo A, whose evaporating gas is easily compressible and liquefied, and liquid cargo B, whose evaporating gas is not easily compressible and liquefied. Liquid cargo A is loaded into liquid cargo tank CT1, and liquid cargo B is loaded into liquid cargo tank CTn. The deck tank DT is used to load liquid cargo A. The port side loading and unloading pipe group 11 is still used as the shore access interface.

[0081] The loading / unloading arm for loading liquid cargo A at the terminal is connected to L101a, and the return air arm is connected to L102a. The loading / unloading arm for loading / unloading liquid cargo B is connected to L104a, and the return air arm is connected to L103a. First, valves V304a, V303a, V302a, V211a, V213a, V209a, V207a, V601, V604, and V608 are opened. Liquid cargo A enters the liquid cargo heat exchanger HE301 via L101a→L306a→L305a, where it is heated and vaporized by ambient seawater. The vaporized liquid cargo A then enters the liquid cargo tank CT via L304a→L302a→L202→L208a→L210a→L211a. At the bottom of tank 1, the nitrogen gas in cargo tank CT1 and deck tank DT is displaced through L304a→L302a→L202→L601→L603→L605. The nitrogen gas and cargo A vapor are discharged through pipe L207a at the top of cargo tank CT1 and pipe L610 at the top of deck tank DT, and then discharged to the shore station receiving equipment through L207a→L205a→L204→L102a and L610→L612→L204→L102a respectively.

[0082] With the continuous input of liquid cargo A vapor, once the concentration of liquid cargo A vapor in liquid cargo tank CT1 and deck tank DT reaches the required level, the cargo tank purging process is completed. After the liquid cargo tank CT1 and deck tank DT are purged, valves V202a, V214a, and V603 are opened, and valves V304a, V213a, and V604 are closed. Liquid cargo A no longer enters the liquid cargo heat exchanger HE301 to be heated into vapor, but instead directly flows through L101a→L202→L208a→L210a→L212a and L101a→L202→L601→L603→L604, spraying from the top into liquid cargo tank CT1 and deck tank DT respectively. Liquid cargo A in the liquid cargo tank... Heat absorption and vaporization occur in CT1 and deck tank DT, gradually lowering the temperature of CT1 and deck tank DT. By controlling the flow rate of liquid cargo A, the cooling rate is kept below a specified value. Valves V209a and V207a are opened, and the vapors generated in CT1 return to the dock receiving unit via L207a→L205a→L204→L102a. Valve V608 is opened, and the vapors generated in deck tank DT return to the dock receiving unit via L610→L612→L204→L102a. Once the temperature of CT1 and deck tank DT drops to the set low temperature, the pre-cooling process is complete.

[0083] The purging and precooling of the liquid cargo tank CTn are carried out using the same methods as those for the liquid cargo tank CT1, and are performed simultaneously. The difference is that the operation of the liquid cargo tank CTn is carried out by liquid cargo B, requiring the use of L104a (liquid phase) and L103a (gas phase), the liquid cargo vaporizer to be HE302, and the loading and unloading manifold to be L201 (liquid phase) and L203 (gas phase), in order to avoid mixing of liquid cargo A and liquid cargo B.

[0084] 3. After the pre-cooling operations of cargo tanks CT1, CTn, and deck tank DT are completed, based on the valve status during the pre-cooling operation, open valve V213a and close valve V214a. Cargo A is loaded into cargo tank CT1 via L101a→L202→L208a→L210a→L211a; open valve V213b and close valve V214b. Cargo B is loaded into cargo tank CTn via L104a→L201→L209b→L210b→L211b; open valve V604 and close valve V603. Cargo A is loaded into deck tank DT via L101a→L202→L601→L603→L605. This achieves simultaneous loading of cargo tanks CT1, CTn, and DT until loading is complete.

[0085] 4. During transportation, liquid cargo absorbs heat from the environment, generating evaporative gases, which leads to increased temperature and pressure within the cargo hold. Therefore, it is necessary to treat these evaporative gases to maintain the correct temperature and pressure. For easily compressible and liquefiable liquid cargo A evaporative gases, when the pressure in cargo hold CT1 rises to a certain value, valves V209a, V501, EV51, V504, V212a, and V214a are opened. The evaporative gases in cargo hold CT1 enter the evaporative gas compressor BC501 via L207a→L205a→L204→L501→L503. After pressurization, the evaporative gases enter the evaporative gas liquefaction unit HE501. The high-pressure evaporative gases are liquefied by cooling with ambient temperature seawater and then enter the gas-liquid separator KOD. 501. In gas-liquid separator KOD501, the high-pressure, room-temperature liquid cargo A is throttled by expansion valve EV51, resulting in a pressure reduction. Part of the liquid cargo A flashes and vaporizes, absorbing its own heat, thus becoming a low-temperature, low-pressure gas-liquid mixture. This mixture then enters gas-liquid separator KOD502, forming a liquid low-temperature, low-pressure liquid cargo A. The liquid low-temperature, low-pressure liquid cargo A flows through L507→L201→L209a→L210a→L212a from the top into cargo tank CT1, thereby reducing the pressure and temperature within cargo tank CT1. When the gaseous low-temperature, low-pressure liquid cargo A in gas-liquid separator KOD502 accumulates to a sufficient quantity, valve V505 is opened, and the gaseous low-temperature, low-pressure liquid cargo A enters the evaporator compressor BC501 through L511 for compression and liquefaction.

[0086] For the incompressible and liquefied cargo B, when the pressure in the cargo tank CTn rises to a certain value, valves V216b, V401b, V402b, V211b, V214b, the cargo pump CPn, and the refrigeration unit RU401 are opened. The cargo pump CPn transfers the cargo B from the cargo tank CTn and through L214b→L401b→L402 into the cryogenic heat exchanger HE401. The refrigeration unit RU401 generates a refrigerant at a temperature lower than the saturation temperature of the cargo B, which then enters the liquid cargo cryogenic heat exchanger HE401 through L406. The cryogenic heat exchanger HE501 cools the liquid cargo B to a cryogenic state. The refrigerant returns to the refrigeration unit RU401 through L405. The cryogenically cooled liquid cargo B is injected into the liquid cargo tank CTn from the top through L403→L202→L208b→L210b→L212b. As the cryogenically cooled liquid cargo falls from the top of the liquid cargo tank CTn, it contacts and exchanges heat with the evaporated gas of the liquid cargo B in the upper part of the liquid cargo tank CTn, thereby cooling the evaporated gas and realizing the reliquefaction of the evaporated gas of the liquid cargo B, reducing the temperature and pressure of the liquid cargo tank CTn.

[0087] 5. When liquid cargo A is stored in deck tank DT, it also absorbs ambient heat. Liquid cargo A evaporates to produce vapor gas, which increases the pressure and temperature of deck tank DT. Typically, deck tanks use a type C design, which has a certain pressure resistance. When the pressure rises to the design value, fuel pumps FP601, V605, V606, V603, EV52, and V506 are activated. Part of the liquid cargo A is transferred out of deck tank DT and enters the cryogenic fuel heat exchanger HE601 via L606→L607. The high-temperature, high-pressure liquid cargo A in the gas-liquid separator KOD501 is throttled by the expansion valve EV52, resulting in a pressure reduction and flash evaporation. The high-temperature, high-pressure liquid cargo A vaporizes into a low-temperature, low-pressure gas-liquid mixture, which then enters the cryogenic fuel heat exchanger HE601. It absorbs the heat from the liquid cargo A transferred out of deck tank DT, keeping the liquid cargo A transferred out of deck tank DT in a cryogenic state. Meanwhile, the low-temperature, low-pressure liquid cargo A that enters the cryogenic fuel heat exchanger HE601 from the gas-liquid separator KOD501 is completely vaporized into a gaseous state and enters the evaporative gas compressor BC501 via L510. After being cryogenically cooled, liquid cargo A is sprayed from the top to the deck tank DT via L608→L603→L604. During the descent of the sprayed liquid cargo A, it comes into contact with the evaporating gas in the upper part of the deck tank DT for heat exchange, thereby cooling the evaporating gas and liquefying it, ultimately reducing the temperature and pressure inside the deck tank DT.

[0088] 6. After the transport ship arrives at the port, taking the loading and unloading pipe group 11 on the port side of the ship as the shore access interface as an example, the liquid phase unloading arm of liquid cargo A at the terminal is connected to L101a and the gas phase unloading arm is connected to L102a.

[0089] If the liquid cargo tank CT1 is a pressurized type C cargo tank, then valve V215a can be opened to use the pressure inside the tank to push liquid cargo A out through L213a to L210a. Then, valve V212a can be opened to allow liquid cargo A to enter the liquid phase main pipe L201. The subsequent operation process will be described below according to the different situations of the terminal liquid cargo receiving device.

[0090] If cargo hold A is a non-pressurized Type A or Type B hold, open valve V216a and use cargo pump CP1 to transfer cargo A from cargo hold CT1 to L210a via L214a. Open valve V212a and cargo A enters the liquid phase manifold L201. The subsequent operation process will be described below according to the different situations of the terminal cargo receiving device.

[0091] If the terminal's liquid cargo receiving device is a low-temperature, low-pressure, fully refrigerated storage tank, then valve V201a is opened, and liquid cargo A is directly transported from the liquid phase main pipe L201 through L101a to the terminal unloading arm and enters the receiving storage tank.

[0092] If the terminal's liquid cargo receiving unit is a medium-temperature, medium-pressure, semi-cooled, semi-pressurized storage tank, there may be a certain pressure within the receiving unit. If the discharge pressure of the liquid cargo pump CP1 is sufficient to discharge liquid cargo A from the liquid cargo tank CT1 into the receiving unit, then valves V216a, V212a, V201a, and liquid cargo pump CP1 should be opened. Liquid cargo A will then be discharged to the terminal receiving unit via L214a→L210a→L209a→L201→L101a through liquid cargo pump CP1. If the discharge pressure of cargo pump CP1 cannot guarantee the smooth discharge of cargo A from cargo tank CT1 into the receiving device, then after cargo pump CP1 discharges cargo A to pipe L201, valves V301a, V304a, and cargo booster pump BP1 are opened. Cargo A flows from pipe L201 through L301a into cargo booster pump BP1 for secondary pressurization, and then through L303a→L305a→L306a→L101a to the dock receiving device. Of course, for pressurized Type C cargo tanks, similar operations can be performed based on the pressure of cargo A entering the liquid phase main pipe L201, which will not be elaborated here.

[0093] If the terminal receiving device is a full-pressure storage tank with normal temperature and high pressure, then the tank cannot accept cryogenic liquid cargo. In this case, after liquid cargo A enters the liquid phase main pipe L201, valves V301a and V304a are opened. Liquid cargo A in the liquid phase main pipe L201 enters the liquid cargo booster pump BP1 through L301a for secondary pressurization. After pressurization, liquid cargo A enters the liquid cargo heat exchanger HE301, where the cryogenic liquid cargo A is heated to normal temperature liquid cargo A by normal temperature seawater. After secondary pressurization, liquid cargo A will not vaporize due to temperature increase and will remain in a normal temperature and high pressure liquid state. Then, it enters the terminal receiving device through L305a, L306a, and L101a.

[0094] The unloading method for liquid cargo B in cargo tank CTn is the same as the unloading process for liquid cargo A in cargo tank CT1, and will not be described in detail. However, it should be noted that, in order to avoid mixing with liquid cargo A, liquid cargo B is transported during the unloading process by opening relevant valves and using components such as the liquid phase main pipe L202, pipe L104a, liquid cargo booster pump BP2, and liquid cargo heat exchanger HE302 (corresponding to the second liquid cargo pressurization and heating assembly 32).

[0095] 7. For fully refrigerated liquid cargo tanks such as Type A and Type B tanks, the pressure in the liquid cargo tank is relatively low during liquid cargo transportation projects. During the unloading process, the large discharge flow of liquid cargo can easily lead to negative pressure in the liquid cargo tank, resulting in damage to the liquid cargo tank.

[0096] Taking the liquid cargo tank CT1 as an example, during the unloading of liquid cargo A, the vaporized gas of liquid cargo A in the receiving device is transported to pipe L102a through the terminal vapor phase unloading arm, and V205a and V210a are opened. The vaporized gas returns to the liquid cargo tank A through L102a→L203→L206a→L207a to compensate for the pressure loss caused by the unloading of liquid cargo and ensure the safety of the cargo tank.

[0097] If the terminal receiving device is a low-temperature, low-pressure, fully refrigerated storage tank, the pressure in the receiving device is also relatively low. There may be a situation where the terminal cannot return the vaporized liquid cargo to the transport ship. In this case, during the unloading of liquid cargo A, valves V301a, V303a, V305a, V205a, and V210a are opened. This allows a portion of liquid cargo A in the liquid phase main pipe L201 of unloading liquid cargo A to enter the liquid cargo heat exchanger HE301 through L301a→L304a→L303a (bypassing the liquid cargo booster pump BP1). The ambient temperature seawater heats up this portion of liquid cargo A. Since liquid cargo A has not been pressurized twice by the liquid cargo booster pump BP1, its pressure is low. After being heated, it vaporizes to generate vaporized liquid cargo A. The vaporized liquid cargo A then enters the liquid cargo tank A through L305a→L307a→L102a→L203→L206a→L207a to compensate for the pressure drop in the liquid cargo tank CT1 caused by the unloading of liquid cargo A.

[0098] The method for compensating for the pressure drop in the cargo tank CTn caused by the unloading of cargo B is the same as that in cargo tank CT1, and will not be repeated here. However, it should be noted that in order to avoid mixing of the cargo, it is necessary to control the opening of relevant valves and select the gas phase main pipe L204, pipe L103a, and cargo heat exchanger HE302 (corresponding to the second cargo pressurization and heating component 32) for relevant operations.

[0099] 8. The liquid cargo A in the deck tank DT can be supplied to the clean fuel supply system via fuel pump FP601 and L609, and then supplied to the engine for combustion after processing. On the other hand, since both the deck tank DT and the liquid cargo tank CT1 store liquid cargo A, the liquid cargo A in the deck tank DT can also be used as a cooling medium for the liquid cargo tank CT1.

[0100] For example, after unloading liquid cargo A, during the process of loading liquid cargo A at the next port, the liquid cargo tank CT1 will absorb ambient heat, causing its temperature to rise and making it unsuitable for loading and unloading. If the dock provides cooling for the liquid cargo A upon arrival at the port, it will result in a longer berthing time, extending the ship's transit cycle and increasing berthing costs. At this point, near the dock, valves V605, V606, V602, V212a, V214a, and fuel pump FP601 are opened. A portion of liquid cargo A from deck tank DT is transferred out through fuel pump FP601 and sprayed from the top of liquid cargo tank CT1 via L606→L607→L608→L603→L602→L201→L209a→L210a→L212a. The sprayed liquid cargo A vaporizes in liquid cargo tank CT1, absorbing heat and cooling the tank to the required temperature for the next loading. During this process, the evaporated gas of liquid cargo A generated in the liquid cargo tank CT1 is directly sent to the compression and reliquefaction assembly 5, where it can be liquefied through direct compression, which will not be elaborated here. Correspondingly, the portion of liquid cargo A transferred from the deck tank DT can pass through the fuel cryogenic heat exchanger HE601 during its flow through pipe L607→L608, allowing for appropriate cryogenic heat exchange based on the actual temperature of the material.

[0101] 9. When the liquid cargo tanks CT1~CTn and the deck tank DT require internal maintenance, the warming, inerting, and venting procedures for the liquid cargo tanks CT1~CTn and the deck tank DT must be carried out.

[0102] Taking cargo tank CT1 as an example, after liquid cargo A is unloaded from cargo tank CT1, valves V210a, V502, V507, V504, V212a, V213a, and evaporative gas compressor BC501 are opened. The residual evaporative gas of liquid cargo A in cargo tank CT1 enters evaporative gas compressor BC501 through L207a→L206a→L203→L502→L503, and then is discharged into evaporative gas liquefaction unit HE501 through pipe L504. After heat exchange, it is sent to L507 through pipe L512. When the evaporating gas of liquid cargo A does not pass through the expansion valve, the back pressure of the evaporating gas compressor BC501 is low, and the evaporating gas compressor BC501 has little impact on the pressure and temperature of the evaporating gas. After the evaporating gas enters the evaporating gas liquefaction unit HE501, it is heated to room temperature by the room temperature seawater and enters the bottom of the liquid cargo tank CT1 via L512→L507→L201→L209a→L210a→L211a to warm up the liquid cargo tank CT1. When the temperature of the liquid cargo tank CT1 rises to the specified value, the warming operation of the liquid cargo tank CT1 is completed.

[0103] Following the drying and inerting process described earlier for the liquid cargo tanks, nitrogen and dry air were sequentially introduced into the tanks via the dock to complete the warming, inerting, and venting operations for liquid cargo tank CT1. This ensured that the internal temperature and oxygen content of liquid cargo tank CT1 met the operational requirements for personnel, after which internal maintenance was carried out on liquid cargo tank CT1. The warming, inerting, and venting methods for liquid cargo tanks CTn and deck tank DT are the same as those for liquid cargo tank CT1, and will not be repeated here.

[0104] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A liquid cargo handling system suitable for liquefied gas transport ships carrying various types of goods, characterized in that, The system includes a loading and unloading main pipe assembly (2), at least one loading and unloading pipe assembly, and at least two liquid cargo tanks. The loading and unloading pipe assembly includes at least two liquid phase pipes and at least two gas phase pipes. The loading and unloading main pipe assembly (2) has four main pipes, including two liquid phase main pipes and two gas phase main pipes. Any two main pipes are connected in parallel. Any liquid phase pipe can be connected to any liquid phase main pipe, and any gas phase pipe can be connected to any gas phase main pipe. The liquid cargo tank has a cargo tank loading and unloading pipe assembly (21). The liquid cargo tank can be connected to any liquid phase main pipe and any gas phase main pipe through the cargo tank loading and unloading pipe assembly (21). The cargo hold loading and unloading pipe assembly (21) includes a liquid phase loading and unloading pipe and a gas phase loading and unloading pipe. One end of the liquid phase loading and unloading pipe can be connected to any liquid phase main pipe, and the other end can be connected to the liquid cargo tank. One end of the gas phase loading and unloading pipe can be connected to any gas phase main pipe, and the other end can be connected to the liquid cargo tank. The liquid cargo tank is equipped with a top spray pipe and a bottom loading pipe. The liquid phase loading and unloading pipe can be connected to the top spray pipe and the bottom loading pipe. The gas phase loading and unloading pipe is connected to the top of the liquid cargo tank. The liquid cargo tank is equipped with a liquid cargo pump and a self-pressurized unloading pipe. The suction port of the liquid cargo pump is located in the bottom space of the liquid cargo tank. The outlet of the liquid cargo pump can be connected to the liquid phase loading and unloading pipe. One end of the self-pressurized unloading pipe is connected to the bottom space of the liquid cargo tank, and the other end is connected to the liquid phase loading and unloading pipe. The system includes at least two sets of liquid cargo pressurization and heating components. Each liquid cargo pressurization and heating component includes a pressurization and heating pipe. One end of the pressurization and heating pipe can be connected to any liquid phase main pipe, and the other end can be connected to any liquid phase pipeline. A pressurization pump and a liquid cargo heat exchanger are sequentially arranged along the flow path of the liquid cargo unloading. The pressurization and heating pipe can be connected to any gas phase pipeline. The pressurization and heating pipe includes a bridge pipe. The bridge pipe is connected in parallel with the pressurization pump, and both the bridge pipe and the pressurization pump are connected in series with the liquid cargo heat exchanger.

2. The liquid cargo handling system for liquefied gas transport ships of various cargo types according to claim 1, characterized in that, The loading and unloading pipe assembly includes, in sequence, a first liquid phase pipe, a first gas phase pipe, a second gas phase pipe, a second liquid phase pipe, a third liquid phase pipe, and a third gas phase pipe.

3. A liquid cargo handling system suitable for liquefied gas transport ships carrying various types of goods, as described in claim 1, characterized in that, The system includes a cryogenic assembly (4) and a compression-reliquefaction assembly (5). The inlet side of the cryogenic assembly (4) can be connected to the outlet pipe of the liquid cargo pump of any liquid cargo tank, and the outlet side of the cryogenic assembly (4) can be connected to any liquid phase main pipe of the loading and unloading main pipe group (2). The inlet side of the compression-reliquefaction assembly (5) can be connected to any gas phase main pipe of the loading and unloading main pipe group (2), and the outlet side of the compression-reliquefaction assembly (5) can be connected to any liquid phase main pipe of the loading and unloading main pipe group (2).

4. A liquid cargo handling system suitable for liquefied gas transport ships carrying various types of goods, as described in claim 1, characterized in that, The system includes a fuel assembly (6), which includes a deck tank DT. The deck tank DT can be connected to any liquid phase main of the loading and unloading main assembly (2) or any gas phase main of the loading and unloading main assembly (2). The deck tank DT is equipped with a fuel supply pump FP601 and a fuel supply pipe L609. The suction port of the fuel supply pump FP601 is located in the bottom space of the deck tank DT. The outlet pipe L606 of the fuel supply pump FP601 is connected to the fuel supply pipe L609. The fuel supply pipe L609 can be connected to a clean fuel supply system.

5. A liquid cargo handling system suitable for liquefied gas transport ships carrying various types of goods, as described in claim 4, characterized in that, The system includes a compression-reliquefaction assembly (5), which includes an evaporative gas compressor BC501, an evaporative gas liquefier HE501, a liquefied gas-liquid separator KOD501, and a liquefied gas-liquid separator KOD502 connected in sequence. The inlet of the evaporative gas compressor BC501 can be connected to any one of the gas phase main pipes of the loading and unloading main pipe group (2), and the outlet of the liquefied gas-liquid separator KOD502 can be connected to any one of the liquid phase main pipes of the loading and unloading main pipe group (2).

6. A liquid cargo handling system suitable for liquefied gas transport ships carrying various types of cargo, as described in claim 5, is characterized in that... The fuel assembly (6) includes a cryogenic fuel heat exchanger HE601, with the fuel inlet pipe L607 of the cryogenic fuel heat exchanger HE601 connected to the outlet pipe L606 of the fuel supply pump FP601, and the fuel outlet pipe L608 of the cryogenic fuel heat exchanger HE601 connected to the fuel liquid phase pipe; the liquefied gas gas-liquid separator KOD501 is provided with a discharge pipe L509, which is connected to the cold source inlet of the cryogenic fuel heat exchanger HE601 through an expansion valve EV52, and the cold source outlet of the cryogenic fuel heat exchanger HE601 is provided with a pipe L510, which is connected to the inlet pipe L503 of the evaporative gas compressor BC501 through the pipe L510.

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