Marine liquefied gas self-pressurization drainage system and drainage method

Abstract

The invention provides a marine liquefied gas self-pressurization liquid drainage system and a liquid drainage method.The liquid drainage system is provided with a first heating pipeline and a second heating pipeline, and liquid cargo enters an inlet three-way valve through a pressurization inlet pipeline; liquid cargo flowing out of the inlet three-way valve is heated and gasified through the first heating pipeline and / or the second heating pipeline, then enters the outlet three-way valve and flows back to the liquid tank through the pressurizing outlet pipeline, and therefore the pressure of the liquid tank is increased to meet the liquid discharging requirement. The liquid drainage system can effectively achieve the liquid drainage function of the liquid tank without an immersed pump, and the pressure in the liquid tank is automatically adjusted through air heating and electric heating, so that the liquid drainage speed is adjusted. Compared with a deep-well pump, the cost is low, installation and maintenance are easy and convenient, and the safety and stability of the drainage system are more reliable than those of the deep-well pump. And a stable, safe and effective scheme is provided for the liquefied gas drainage system for the ship.

Description

Technical Field

[0001] The present invention relates to the technical field of ship design and manufacturing, and particularly to a marine liquefied gas self-pressurizing liquid drainage system and a liquid drainage method. Background Art

[0002] Methanol, ammonia, natural gas, and liquefied petroleum gas are currently the most mainstream clean energies applied in the shipping industry. Carbon capture is one of the main ways for the shipping industry to achieve carbon neutrality in the future. With the technological maturity of various dual-fuel main engines and generators, more and more ships use methanol, ammonia, natural gas, and liquefied petroleum gas as fuels. The storage and transportation of liquefied gases are becoming more frequent and important. Among them, deep-well pumps are one of the most critical equipment in the transportation process. Currently, marine liquid cargo deep-well pumps are mainly supplied by foreign brands such as Shinko, Vanzetti, and Cryostar. They are expensive, have a long supply cycle, and the after-sales service costs are high and not guaranteed.

[0003] Therefore, it is necessary to design a liquid drainage method to achieve the liquid drainage function without the need for a deep-well pump, so as to get rid of the dependence on marine liquid cargo deep-well pumps. Summary of the Invention

[0004] In view of the above-mentioned disadvantages of the prior art, the purpose of the present invention is to provide a marine liquefied gas self-pressurizing liquid drainage system and a liquid drainage method. The system autonomously adjusts the pressure in the liquid tank through air heating and electric heating, thereby adjusting the liquid drainage speed and achieving the liquid drainage function. The system can achieve the liquid drainage function without the need for a deep-well pump, and the safety and stability of the liquid drainage system are more reliable than those using a deep-well pump.

[0005] To achieve the above purpose and other related purposes, the present invention provides a marine liquefied gas self-pressurizing liquid drainage system, including a liquid tank. The upper side wall and the lower side wall of the liquid tank are respectively provided with an inlet pipeline and an outlet pipeline. The inlet pipeline is used for filling liquid cargo, and the outlet pipeline is used for transporting the liquid cargo in the liquid tank out;

[0006] The upper side wall and the lower side wall of the liquid tank are also respectively connected to a pressurization outlet pipeline and a pressurization inlet pipeline. The port of the pressurization inlet pipeline far from the liquid tank is connected to an inlet three-way valve, and the port of the pressurization outlet pipeline far from the liquid tank is connected to an outlet three-way valve. A first heating pipeline and a second heating pipeline are arranged in parallel between the inlet three-way valve and the outlet three-way valve. The liquid cargo enters the inlet three-way valve through the pressurization inlet pipeline, and the liquid cargo flowing out of the inlet three-way valve is heated and vaporized through the first heating pipeline and / or the second heating pipeline, then enters the outlet three-way valve and flows back to the liquid tank through the pressurization outlet pipeline, thereby increasing the pressure in the liquid tank.

[0007] Optionally, the connection port between the upper side wall of the liquid tank and the pressurization inlet pipeline is above the liquid level of the liquid tank.

[0008] Optionally, the liquid tank is provided with a safety valve port and a pressure sensor.

[0009] Optionally, an air vaporizer is provided in the first heating pipeline, and an electric heating vaporizer is provided in the second heating pipeline.

[0010] Optionally, two ball valves are provided in the first heating pipeline, and the two ball valves are respectively connected to both ends of the air vaporizer; two ball valves are also provided in the second heating pipeline, and the two ball valves are respectively connected to both ends of the electric heating vaporizer; the two ball valves in the first heating pipeline open and close simultaneously, and the two ball valves in the second heating pipeline also open and close simultaneously.

[0011] Optionally, pneumatic ball valves are provided in both the pressurized outlet pipeline and the pressurized inlet pipeline.

[0012] Optionally, a drain port is further provided at the bottom of the liquid tank.

[0013] The present invention also provides a liquid discharging method for the marine liquefied gas self-pressurizing liquid discharging system as described above, including the following steps:

[0014] S1. Before the liquid tank operates, liquid cargo is filled through the inlet pipeline, and after the filling is completed, the inlet pipeline is closed;

[0015] S2. The liquid cargo in the liquid tank is transported through the outlet pipeline, and the liquid discharging rate is adjusted by controlling different pressures maintained inside the liquid tank;

[0016] S3. When the required liquid discharging rate of the liquid tank is small, the first heating pipeline is in a through state, the second heating pipeline is in a cut-off state, the air vaporizer is opened, and the electric heating vaporizer is closed; the liquid cargo is heated and vaporized by the air vaporizer and then flows back to the liquid tank, and the pressure of the liquid tank increases to reach the liquid discharging pressure;

[0017] S4. When the required liquid discharging rate of the liquid tank is large, both the first heating pipeline and the second heating pipeline are in a through state, the air vaporizer is opened, and the electric heating vaporizer is opened; the liquid cargo is heated and vaporized by the air vaporizer, and at the same time, the liquid cargo is heated and vaporized by the electric heating vaporizer, and the pressure of the liquid tank rapidly rises to reach the liquid discharging pressure;

[0018] S5. After the liquid discharging of the liquid tank is completed, the air vaporizer is closed, the electric heating vaporizer is closed, and the pneumatic ball valve is closed;

[0019] S6. The self-pressurizing liquid discharging system completes the liquid discharging.

[0020] As described above, the present invention provides a marine liquefied gas self-pressurizing liquid discharging system and a liquid discharging method. The liquid discharging system is provided with a first heating pipeline and a second heating pipeline. The liquid cargo enters the inlet three-way valve through the pressurizing inlet pipeline. The liquid cargo flowing out of the inlet three-way valve enters the outlet three-way valve after being heated and vaporized by the first heating pipeline and / or the second heating pipeline and flows back to the liquid tank through the pressurizing outlet pipeline, so that the pressure in the liquid tank rises to meet the liquid discharging requirements. The liquid discharging system can effectively realize the liquid discharging function of the liquid tank without a submerged pump, and autonomously adjust the pressure in the liquid tank through air heating and electric heating, thereby adjusting the liquid discharging speed. It is relatively cheap compared to deep well pumps, and the installation and maintenance are simple and convenient. The safety and stability of the liquid discharging system are more reliable than those using deep well pumps. It provides a stable, safe and effective solution for the marine liquefied gas liquid discharging system. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It shows a schematic diagram of the pipeline connection of the marine liquefied gas self-pressurizing liquid discharging system in Embodiment 1 of the present invention.

[0022] DESCRIPTION OF REFERENCE NUMERALS

[0023] 1. Liquid tank; 2. Electric heating vaporizer; 3. Air vaporizer; 4. Pressure sensor; 5. Safety valve; 6. Pneumatic ball valve; 7. Pneumatic ball valve; 8. Outlet three-way valve; 9. Inlet three-way valve; 10. Ball valve; 11. Ball valve; 12. Ball valve; 13. Ball valve. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] The following specific examples illustrate the embodiments of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0025] When detailing the embodiments of the present invention, for the sake of convenience of description, the cross-sectional views showing the device structure will be enlarged locally out of the general proportion, and the schematic diagrams are only examples and should not limit the scope of protection of the present invention here. In addition, in actual production, three-dimensional spatial dimensions including length, width and depth should be included.

[0026] For ease of description, spatial relationship terms such as "below", "beneath", "lower", "under", "above", "upper", etc. may be used herein to describe the relationship of one element or feature shown in the drawings to other elements or features. It will be understood that these spatial relationship terms are intended to encompass other orientations of the device in use or operation, in addition to the orientation depicted in the drawings. Further, when a layer is referred to as being "between" two layers, it can be the only layer between the two layers, or there can be one or more intervening layers. As used herein, "between... and..." means including the endpoint values.

[0027] In the context of the present application, the structure in which the first feature described is "above" the second feature may include an embodiment in which the first and second features are formed in direct contact, or may include an embodiment in which additional features are formed between the first and second features, such that the first and second features may not be in direct contact.

[0028] It should be noted that the diagrams provided in this embodiment only schematically illustrate the basic concept of the present invention. Therefore, only the components related to the present invention are shown in the diagrams, rather than being drawn according to the number, shape, and size of the components in actual implementation. The types, quantities, and proportions of the components in actual implementation can be arbitrarily changed, and the component layout type may also be more complex.

[0029] Embodiment 1

[0030] As Figure 1 shown, this embodiment provides a marine liquefied gas self-pressurizing drainage system, including:

[0031] A liquid tank 1, an inlet pipeline A and an outlet pipeline B are respectively provided on the upper side wall and the lower side wall of the liquid tank 1. The inlet pipeline A is used for filling liquid cargo, and the inlet pipeline A is closed after filling is completed; the outlet pipeline B is used for transferring the liquid cargo in the liquid tank 1 out.

[0032] The upper side wall and the lower side wall of the liquid tank 1 are also respectively communicated with a pressurization outlet pipeline and a pressurization inlet pipeline. The port of the pressurization inlet pipeline far from the liquid tank 1 is connected to an inlet three-way valve 9, and the port of the pressurization outlet pipeline far from the liquid tank 1 is connected to an outlet three-way valve 8. A first heating pipeline and a second heating pipeline arranged in parallel are connected between the inlet three-way valve 9 and the outlet three-way valve 8. The liquid cargo enters the inlet three-way valve 9 through the pressurization inlet pipeline, and the liquid cargo flowing out of the inlet three-way valve 9 is heated and vaporized through the first heating pipeline and / or the second heating pipeline, then enters the outlet three-way valve 8 and flows back to the liquid tank 1 through the pressurization outlet pipeline. Among them, the communication port between the upper side wall of the liquid tank 1 and the pressurization inlet pipeline is above the liquid level of the liquid tank 1, that is, in the gas phase space at the top of the liquid tank.

[0033] Further, an air vaporizer 3 is provided in the first heating pipeline, and an electric heating vaporizer 2 is provided in the second heating pipeline. Specifically, the air vaporizer 3 relies on the convection of natural air or forced ventilation to absorb ambient heat. The liquid cargo flows through the finned tubes or heat exchangers of the air vaporizer 3 and exchanges heat with the air, absorbing the heat in the air to vaporize. During the process, no external energy is required and it completely depends on the ambient temperature, which is energy-saving and environmentally friendly but has a low heating efficiency. The electric heating vaporizer 2 directly provides heat through electric heating elements (such as resistance wires). The liquid cargo flows through the heat exchange pipeline with an in-built electric heater and is vaporized by electric energy. During the process, it depends on electricity and has a high energy consumption but a high heating efficiency.

[0034] Further, two ball valves 10 and 11 are provided in the first heating pipeline, and the two ball valves 10 and 11 are respectively arranged at both ends of the air vaporizer 3. Two ball valves 12 and 13 are also provided in the second heating pipeline, and the two ball valves 12 and 13 are respectively arranged at both ends of the electric heating vaporizer 2. The two ball valves in the first heating pipeline open and close simultaneously, and the two ball valves in the second heating pipeline also open and close simultaneously, so that the liquid cargo flowing out of the inlet three-way valve can selectively enter the first heating pipeline, or the second heating pipeline, or enter both heating pipelines simultaneously. Correspondingly, pneumatic ball valves 6 and 7 are provided in both the pressurized outlet pipeline and the pressurized inlet pipeline.

[0035] Further, the liquid tank is provided with a safety valve port 5, the liquid tank 1 is provided with a pressure sensor 4, the liquid tank 1 is also provided with other auxiliary interfaces, and a drain port is provided at the bottom of the liquid tank 1. The drain port is used to drain the liquid, completely drain the residual liquid in the tank, avoid corrosion or pollution caused by accumulation, and at the same time facilitate flushing the sediment at the bottom of the tank. The safety valve port is a key component to ensure the safe pressure relief of the liquid tank in case of abnormal pressure, and it is usually arranged in the gas phase space at the top of the liquid tank. The pressure sensor 4 is used for real-time pressure monitoring, detecting the pressure in the liquid cargo tank to prevent overpressure.

[0036] Based on the above-mentioned marine liquefied gas self-pressurizing liquid discharge system, this embodiment also provides a liquid discharge method, including the following steps:

[0037] S1. Before the operation of the liquid tank 1, liquid cargo is filled through the inlet pipeline A. After the filling is completed, the inlet pipeline A is closed;

[0038] S2. The liquid cargo in the liquid tank 1 is transported through the outlet pipeline B, and the liquid discharge rate is adjusted by controlling the internal pressure of the liquid tank 1 to be maintained at different levels;

[0039] S3. When the required drainage rate of the liquid tank 1 is relatively small, the first heating pipeline is in a passage state, and the second heating pipeline is in a cut-off state. Specifically, open the pneumatic ball valves 6 and 7, the outlet three-way valve 8, the inlet three-way valve 9, the ball valves 10 and 11, close the ball valves 12 and 13, open the air vaporizer 3, and close the electric heating vaporizer 2; the liquid cargo is heated and vaporized by the air vaporizer 3 and then flows back to the liquid tank 1, and the pressure of the liquid tank 1 increases to reach the drainage pressure.

[0040] S4. When the required drainage rate of the liquid tank 1 is relatively large, both the first heating pipeline and the second heating pipeline are in a passage state. Specifically, open the pneumatic ball valves 6 and 7, the outlet three-way valve 8, the inlet three-way valve 9, the ball valves 10 and 11, open the ball valves 12 and 13, open the air vaporizer 3, and open the electric heating vaporizer 2; the liquid cargo is heated and vaporized by the air vaporizer 3, and at the same time, the liquid cargo is heated and vaporized by the electric heating vaporizer 2, and the pressure of the liquid tank 1 rapidly increases to reach the drainage pressure.

[0041] S5. After the drainage of the liquid tank 1 is completed, close the air vaporizer 3, close the electric heating vaporizer 2, and close the pneumatic ball valves 6 and 7.

[0042] S6. The self-pressurizing system completes the drainage.

[0043] In summary, the present invention provides a marine liquefied gas self-pressurizing drainage system and a drainage method. The drainage system is provided with a first heating pipeline and a second heating pipeline. The liquid cargo enters the inlet three-way valve through the pressurization inlet pipeline, and the liquid cargo flowing out of the inlet three-way valve is heated and vaporized by the first heating pipeline and / or the second heating pipeline and then enters the outlet three-way valve and flows through the pressurization outlet pipeline and returns to the liquid tank, so that the pressure of the liquid tank increases to reach the drainage requirement. The drainage system can effectively realize the drainage function of the liquid tank without a submersible pump, and independently adjust the pressure in the liquid tank through air heating and electric heating, so as to adjust the drainage speed. It is relatively cheap compared with deep well pumps, and the installation and maintenance are simple and convenient. The safety and stability of the drainage system are more reliable than those using deep well pumps. It provides a stable, safe and effective solution for the marine liquefied gas drainage system.

[0044] The above embodiments are only illustrative of the principles and effects of the present invention, and are not used to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes completed by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A marine liquefied gas self-pressurizing liquid drainage system, characterized in that, It includes a liquid tank. The upper side wall and the lower side wall of the liquid tank are respectively provided with an inlet pipeline and an outlet pipeline. The inlet pipeline is used for filling liquid cargo, and the outlet pipeline is used for transferring the liquid cargo in the liquid tank out. The upper side wall and the lower side wall of the liquid tank are also respectively communicated with a pressurization outlet pipeline and a pressurization inlet pipeline. The port of the pressurization inlet pipeline far away from the liquid tank is connected to an inlet three-way valve, and the port of the pressurization outlet pipeline far away from the liquid tank is connected to an outlet three-way valve. A first heating pipeline and a second heating pipeline arranged in parallel are connected between the inlet three-way valve and the outlet three-way valve. The liquid cargo enters the inlet three-way valve through the pressurization inlet pipeline, and the liquid cargo flowing out of the inlet three-way valve is heated and vaporized through the first heating pipeline and / or the second heating pipeline and then enters the outlet three-way valve and flows back to the liquid tank through the pressurization outlet pipeline, so as to increase the pressure in the liquid tank.

2. The marine liquefied gas self-pressurizing liquid drainage system according to claim 1, wherein: The connection port between the upper side wall of the liquid tank and the pressurization inlet pipeline is above the liquid level of the liquid tank.

3. The marine liquefied gas self-pressurizing liquid drainage system according to claim 1, characterized in that: The liquid tank is provided with a safety valve port and a pressure sensor.

4. The marine liquefied gas self-pressurizing liquid drainage system according to claim 1, characterized in that: An air vaporizer is provided in the first heating pipeline, and an electric heating vaporizer is provided in the second heating pipeline.

5. The marine liquefied gas self-pressurizing liquid drainage system according to claim 4, wherein: Two ball valves are arranged in the first heating pipeline, and the two ball valves are respectively connected to both ends of the air vaporizer; two ball valves are also arranged in the second heating pipeline, and the two ball valves are respectively connected to both ends of the electric heating vaporizer; the two ball valves in the first heating pipeline open and close simultaneously, and the two ball valves in the second heating pipeline also open and close simultaneously.

6. The marine liquefied gas self-pressurizing liquid drainage system according to claim 5, characterized in that: Pneumatic ball valves are arranged in both the pressurization outlet pipeline and the pressurization inlet pipeline.

7. The marine liquefied gas self-pressurizing liquid drainage system according to claim 1, characterized in that: A drain port is also provided at the bottom of the liquid tank.

8. A liquid discharge method of the marine liquefied gas self-pressurizing liquid discharge system as described in claim 6, characterized in that, It includes the following steps: S1. Before the liquid tank operates, fill the liquid cargo through the inlet pipeline. After filling is completed, the inlet pipeline is closed. S2. The liquid cargo in the liquid tank is transferred through the outlet pipeline, and the drainage rate is adjusted by controlling the internal pressure of the liquid tank to be different. S3. When the required drainage rate of the liquid tank is small, the first heating pipeline is in a through state, the second heating pipeline is in a cut-off state, the air vaporizer is opened, and the electric heating vaporizer is closed; the liquid cargo is heated and vaporized by the air vaporizer and then flows back to the liquid tank, and the pressure of the liquid tank increases to reach the drainage pressure. S4. When the required drainage rate of the liquid tank is large, both the first heating pipeline and the second heating pipeline are in a through state, the air vaporizer is opened, and the electric heating vaporizer is opened; the liquid cargo is heated and vaporized by the air vaporizer, and at the same time the liquid cargo is heated and vaporized by the electric heating vaporizer, and the pressure of the liquid tank rapidly increases to reach the drainage pressure. S5. After the drainage of the liquid tank is completed, the air vaporizer is closed, the electric heating vaporizer is closed, and the pneumatic ball valve is closed. S6. The self-pressurization drainage system completes the drainage.

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