Tank equipment
The tank facility design uses a BOG compressor and heat exchanger to compress boil-off gas for cooling the receiving pipe, addressing the challenge of density reduction and temperature mismatch, ensuring efficient compression and cooling without additional equipment.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- KAWASAKI JUKOGYO KK
- Filing Date
- 2022-03-30
- Publication Date
- 2026-06-24
AI Technical Summary
The challenge is to compress boil-off gas used to cool the receiving piping in a tank facility effectively, as its density decreases after being heated, making it difficult for the boil-off gas compressor to achieve the desired pressure.
A tank facility design that includes a BOG compressor in the BOG piping, a cooling gas supply pipe to cool the receiving pipe using boil-off gas, and a heat exchanger to exchange heat between the cooling gas and liquefied gas, ensuring the cooling gas can be compressed by the BOG compressor.
Enables the boil-off gas to cool the receiving piping effectively while being compressible by the BOG compressor, eliminating the need for additional compressors and maintaining the cooling gas temperature similar to the boil-off gas.
Smart Images
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Abstract
Description
Technical Field
[0006] , , , ,
[0001] The present disclosure relates to tank facilities for storing cryogenic liquefied gases.
Background Art
[0002] Cryogenic liquefied gases such as liquefied hydrogen and LNG (Liquefied Natural Gas) are transported to a receiving base by means of liquefied gas transportation such as a ship and temporarily stored in the tank facilities of the receiving base. Patent Document 1 exemplifies this type of tank facility.
[0003] The tank facility disclosed in Patent Document 1 includes a tank, a receiving pipe for supplying liquefied gas from a transportation means to the tank, a discharge pipe for discharging liquefied gas from the tank to the outside, a boil-off gas pipe for discharging boil-off gas generated in the tank to the outside, a boil-off gas compressor installed in the boil-off gas pipe, and a return gas pipe for returning a part of the boil-off gas to the transportation means.
[0004] When receiving liquefied gas, it is necessary to cool the receiving pipe in order to prevent the vaporization of the liquefied gas. Therefore, Patent Document 1 further includes a bypass pipe that connects the tank facility's receiving pipe and the return gas pipe, and when not receiving liquefied gas, boil-off gas is flowed from the tank in the order of the receiving pipe, the bypass pipe, the return gas pipe, and the boil-off gas pipe to cool the receiving pipe with the boil-off gas.
Prior Art Documents
Patent Documents
[0005]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0006] The boil-off gas produced by vaporization in the tank is heated by cooling the receiving pipe through it. The boil-off gas compressor is selected to compress the low-temperature boil-off gas produced by vaporization in the tank, and its intake gas temperature is corresponding to that of the low-temperature boil-off gas. In other words, since the density of the boil-off gas decreases after it has been heated through the receiving pipe, it is difficult to compress it to the desired pressure using the boil-off gas compressor.
[0007] This disclosure is made in view of the above circumstances, and its purpose is to enable the boil-off gas used to cool the receiving piping in a tank facility to be compressed by a boil-off gas compressor installed in the boil-off gas piping. [Means for solving the problem]
[0008] To solve the above problems, a tank facility according to one aspect of this disclosure is provided. A tank having a liquid inlet, a liquid outlet, and a gas outlet, for storing liquefied gas, A receiving pipe connected to the liquid inlet of the tank, through which the liquefied gas to be received into the tank flows, A discharge pipe is connected to the liquid outlet of the tank, through which the liquefied gas to be discharged from the tank flows, A BOG pipe is connected to the gas outlet of the tank, into which boil-off gas generated by the vaporization of the liquefied gas in the tank flows, A BOG compressor is arranged in the aforementioned BOG piping, A cooling gas supply pipe connected to the upstream portion of the receiving pipe, which supplies the boil-off gas as a cooling gas to the receiving pipe when the liquefied gas is not flowing through the receiving pipe, A cooling gas discharge pipe is connected to the downstream portion of the receiving pipe and the upstream side of the BOG compressor in the BOG pipe, and transports the cooling gas that has flowed through the receiving pipe to the BOG pipe. The system includes a heat exchanger, which is placed in the cooling gas discharge piping and exchanges heat between the cooling gas and the liquefied gas. [Effects of the Invention]
[0009] According to one aspect of the present disclosure described above, in a tank facility, the boil-off gas used to cool the receiving piping can be compressed by a boil-off gas compressor installed in the boil-off gas piping. [Brief explanation of the drawing]
[0010] [Figure 1] Figure 1 is a schematic diagram showing the general configuration of a tank facility according to the first embodiment of this disclosure. [Figure 2] Figure 2 shows the flow of cooling gas during pre-cooling of the receiving piping. [Figure 3] Figure 3 is a schematic diagram showing the general configuration of the tank equipment according to Modification 1. [Figure 4] Figure 4 is a schematic diagram showing the general configuration of the tank equipment according to Modification 2. [Modes for carrying out the invention]
[0011] Next, embodiments of the present disclosure will be described with reference to the drawings. Figure 1 is a schematic diagram showing the general configuration of a tank facility 1 according to one embodiment of the present disclosure. As shown in this figure, the tank facility 1 according to the present disclosure is installed, for example, at a liquefied gas receiving base 11 located in a coastal area. The liquefied gas receiving base 11 is equipped with an unloading arm 5 and a return gas arm 16, and the tank facility 1. The unloading arm 5 and the return gas arm 16 are located on a quay where a liquefied gas transport means 10, such as a liquefied gas transport ship, docks. The tank facility 1 is equipment that receives and stores the liquefied gas 100 transported by the liquefied gas transport means 10, and vaporizes the stored liquefied gas 100 and sends it out to the outside. The liquefied gas 100 stored in the tank facility 1 according to this embodiment is liquefied hydrogen, but the liquefied gas 100 stored in the tank facility 1 according to this disclosure is not limited to this, and may be any low-temperature or cryogenic liquefied gas such as LNG (Liquefied Natural Gas) or cooled LPG (Liquefied Petroleum Gas). Furthermore, the tank facility 1 is not limited to coastal areas, but may be installed on land or at sea, depending on the liquefied gas transport means 10.
[0012] The tank equipment 1 comprises a tank 2, a receiving pipe 3, a discharge pipe 7, a vaporizer 8, a supply gas pipe 9, a return gas pipe 15, a BOG pipe 12, a BOG compressor 14, a bypass pipe 17, and a cooling gas discharge pipe 31.
[0013] Tank 2 is a container for storing liquefied gas 100 in a low-temperature liquid state. Since the liquefied gas 100 in Tank 2 is stored approximately at its boiling point, it naturally vaporizes within Tank 2, generating boil-off gas 300, which accumulates at the top and apex of Tank 2. Tank 2 has a liquid inlet 24, a liquid outlet 25, and a gas outlet 26. The gas outlet 26 opens at the top or apex of Tank 2.
[0014] The receiving pipe 3 connects the unloading arm 5 and the tank 2. The upstream end of the receiving pipe 3 is connected to the unloading arm 5, and the downstream end is connected to the liquid inlet 24 of the tank 2. In the middle of the receiving pipe 3, in its downstream part, a receiving valve 4 for opening and closing the flow path of the receiving pipe 3 is provided. When receiving the liquefied gas 100, the receiving valve 4 is opened, and the low-temperature liquefied gas 100 transported by the liquefied gas transport means 10 is supplied to the receiving pipe 3 through the unloading arm 5, flows into the tank 2 through the receiving pipe 3, and is stored in the tank 2.
[0015] The dispensing pipe 7 connects the liquid outlet 25 of the tank 2 and the inlet of the vaporizer 8. The gas supply pipe 9 is a pipe for sending the vaporized gas 200 to the outside of the tank facility 1. A dispensing pump 6 is provided in the dispensing pipe 7. However, the dispensing pump 6 may be provided in the tank 2. When dispensing the liquefied gas 100 stored in the tank 2, the liquefied gas 100 flowing out into the dispensing pipe 7 is pressurized to the pressure required for sending by the operation of the dispensing pump 6 and sent to the vaporizer 8.
[0016] The vaporizer 8 forcibly vaporizes the liquefied gas 100 into the vaporized gas 200 by, for example, heat-exchanging the water supplied from the outside and the liquefied gas 100 supplied through the dispensing pipe 7. A gas supply pipe 9 is connected to the outlet of the vaporizer 8, and the vaporized gas 200 is sent out to the outside through the gas supply pipe 9.
[0017] The BOG pipe 12 connects the tank 2 and the gas supply pipe 9. The upstream end of the BOG pipe 12 is connected to the gas outlet 26 of the tank 2, and the boil-off gas 300 staying in the upper part of the tank 2 flows out into the BOG pipe 12. The downstream end of the BOG pipe 12 is connected to a connection part P1 arranged in the gas supply pipe 9. The boil-off gas 300 of the tank 2 is sent to the gas supply pipe 9 through the BOG pipe 12, merges with the vaporized gas 200, and is sent out to the outside through the gas supply pipe 9.
[0018] In the middle of the BOG pipe 12, a BOG valve 13 for opening and closing the flow path of the BOG pipe 12 is provided. The BOG valve 13 may be open except during the precooling of the receiving pipe 3 described later. Further, a BOG compressor 14 is provided on the downstream side of the BOG valve 13 in the BOG pipe 12. The BOG compressor 14 may be a reciprocating type including, for example, a cylinder that inhales the low-temperature boil-off gas 300 and a piston that compresses the inhaled boil-off gas 300. The BOG compressor 14 compresses the boil-off gas 300 flowing through the BOG pipe 12 to a pressure comparable to that of the vaporized gas 200 sent out from the vaporizer 8.
[0019] The return gas pipe 15 connects the tank 2 and the return gas arm 16. In the tank facility 1 according to the present embodiment, the upstream portion of the return gas flow path and the upstream portion of the BOG flow path are shared, and the return gas pipe 15 is connected to the gas outlet 26 of the tank 2 via the upstream portion of the BOG pipe 12. More specifically, the upstream end of the return gas pipe 15 is connected to the connection portion P2 on the upstream side of the BOG valve 13 in the BOG pipe 12. However, the upstream end of the return gas pipe 15 may be directly connected to the gas outlet 26 of the tank 2. The downstream end of the return gas pipe 15 is connected to the return gas arm 16. A return gas blower 21 is provided in the middle of the return gas pipe 15. The return gas blower 21 operates, for example, during the precooling of the receiving pipe 3 described later or during the reception of the liquefied gas 100. During the reception of the liquefied gas 100, by operating the return gas blower 21, a part of the boil-off gas 300 in the tank 2 is returned to the loading / unloading tank of the liquefied gas transport means 10 through the return gas pipe 15 and the return gas arm 16, and the decrease in the pressure of the loading / unloading tank accompanying the loading / unloading is compensated. When the pressure of the boil-off gas 300 is sufficiently high, the return gas blower 21 may be omitted.
[0020] The bypass pipe 17 connects the return gas pipe 15 and the receiving pipe 3. The upstream end of the bypass pipe 17 is connected to a connection part P3 located on the return gas pipe 15. The downstream end of the bypass pipe 17 is connected to a connection part P4 located on the upstream part of the receiving pipe 3. It is desirable that the connection part P4 be located closer to the unloading arm 5 on the receiving pipe 3. A bypass valve 18 is provided in the middle of the bypass pipe 17 to open and close the flow path of the bypass pipe 17. The bypass valve 18 is opened when the receiving pipe 3 is pre-cooled (described later) and is otherwise closed.
[0021] The cooling gas discharge pipe 31 connects the receiving pipe 3 and the BOG pipe 12. The upstream end of the cooling gas discharge pipe 31 is connected to a connection part P5 located downstream of the receiving pipe 3 and upstream of the receiving valve 4. The downstream end of the cooling gas discharge pipe 31 is connected to a connection part P6 located upstream of the BOG compressor 14 and downstream of the BOG valve 13 in the BOG pipe 12. A discharge valve 32 that opens and closes the flow path of the cooling gas discharge pipe 31 is provided in the upstream part of the cooling gas discharge pipe 31. The discharge valve 32 is opened when the receiving pipe 3, which will be described later, is pre-cooled, and is otherwise kept closed. A heat exchanger 33 is also provided in the middle of the cooling gas discharge pipe 31. The heat exchanger 33 cools the cooling gas 301 passing through the cooling gas discharge pipe 31 by exchanging heat with the liquefied gas 100 passing through the discharge pipe 7.
[0022] [Pre-cooling of receiving piping 3] Here, the pre-cooling of the receiving pipe 3 will be explained using Figure 2. In the tank equipment 1 with the above configuration, the receiving pipe 3 is pre-cooled before receiving the liquefied gas 100 from the liquefied gas transport means 10. In Figure 2, the flow of cooling gas 301 in the tank equipment 1 during the pre-cooling of the receiving pipe 3 is shown by a thick line. During pre-cooling, the receiving valve 4 and the BOG valve 13 are closed, the bypass valve 18 and the discharge valve 32 are open, and the discharge pump 6, the return gas blower 21, and the BOG compressor 14 are in operation. The discharge pump 6 and the BOG compressor 14 are basically in operation at all times.
[0023] To cool the receiving pipe 3, a cooling gas 301 is flowed into the receiving pipe 3, and the boil-off gas 300 in the tank 2 is used as the cooling gas 301. During pre-cooling, the boil-off gas 300 that has flowed out of the tank 2 flows as the cooling gas 301 in the following order: from the upstream end of the BOG pipe 12 to connection P2, from the upstream end of the return gas pipe 15 to connection P3, through the bypass pipe 17, from connection P4 to connection P5 of the receiving pipe 3, through the cooling gas discharge pipe 31, from connection P6 to the downstream end of the BOG pipe 12, and downstream from connection P1 of the supply gas pipe 9. In this embodiment, the return gas pipe 15 and the bypass pipe 17 function as cooling gas supply pipes 30 that supply low-temperature cooling gas 301 to the receiving pipe 3. The receiving pipe 3 is cooled by the flow of low-temperature cooling gas 301.
[0024] The cooling gas 301, warmed by cooling the receiving pipe 3, flows into the cooling gas discharge pipe 31, where it is cooled by heat exchange with the liquefied gas 100 in the heat exchanger 33 before reaching the inlet of the BOG compressor 14. Here, it is desirable that the cooling gas 301 that reaches the inlet of the BOG compressor 14 is cooled to a temperature similar to that of the boil-off gas 300 flowing out of the tank 2 and through the BOG pipe 12. In this way, the cooling gas 301 used to cool the receiving pipe 3 is sufficiently cold to be compressible by the BOG compressor 14. Therefore, the tank equipment 1 does not need to be equipped with an additional compressor for high-temperature gas compression compared to the BOG compressor 14 in order to compress the cooling gas 301 used to cool the receiving pipe 3.
[0025] When the receiving pipe 3 has cooled to a predetermined temperature, pre-cooling is terminated and the receiving of liquefied gas 100 begins. When pre-cooling is complete, the bypass valve 18 and the discharge valve 32 are closed, and the receiving valve 4 and the BOG valve 13 are opened.
[0026] [Variation 1] Here, we will describe Modification 1 of the above embodiment. Figure 3 is a schematic diagram showing the general configuration of the tank equipment 1 according to Modification 1. In this figure, the flow of cooling gas 301 in the tank equipment 1 during pre-cooling of the receiving pipe 3 is shown by a thick line. In the description of this modification, the same or similar components as in the above embodiment are denoted by the same reference numerals in the drawings, and their descriptions are omitted.
[0027] As shown in Figure 3, in the modified example 1 of the tank equipment 1, an extraction pipe 71 is connected to the discharge pipe 7. The extraction pipe 71 is a pipe that extracts a portion of the liquefied gas 100 flowing through the discharge pipe 7 and returns it to the main flow of the discharge pipe 7. The upstream end of the extraction pipe 71 is connected to a connection part P7 located downstream of the discharge pump 6 of the discharge pipe 7. The downstream end of the extraction pipe 71 is connected to a connection part P8 located downstream of the connection part P7 of the discharge pipe 7. The extraction pipe 71 is equipped with an on-off valve 72 that opens and closes the flow path of the extraction pipe 71, and a heat exchanger 33 located downstream of the on-off valve 72. The on-off valve 72 is opened when the receiving pipe 3 is pre-cooled, and is otherwise closed.
[0028] In the tank equipment 1 according to Modification 1, during the pre-cooling of the receiving pipe 3, the cooling gas 301 heated through the receiving pipe 3 is cooled by heat exchange with the liquefied gas 100 flowing through the extraction pipe 71 in the heat exchanger 33. In other words, a portion of the liquefied gas 100 flowing through the discharge pipe 7 is used to cool the cooling gas 301, while the main flow of liquefied gas 100 flowing through the discharge pipe 7 is not used to cool the cooling gas 301. This makes it possible to suppress the temperature rise of the liquefied gas 100 flowing through the discharge pipe 7.
[0029] [Variation 2] Next, a modified example 2 of the above embodiment will be described. Figure 4 is a schematic diagram showing the general configuration of the tank equipment 1 according to modified example 2. In this figure, the flow of cooling gas 301 in the tank equipment 1 during pre-cooling of the receiving pipe 3 is shown by a thick line. In the description of this modified example, the same or similar components as in the above embodiment are denoted by the same reference numerals in the drawings, and their descriptions are omitted.
[0030] As shown in Figure 4, in the modified tank equipment 1 according to the 2nd modification, a circulation pipe 73 is connected to the discharge pipe 7. The circulation pipe 73 is a pipe for taking out a portion of the liquefied gas 100 flowing through the discharge pipe 7 and returning it to the tank 2. The upstream end of the circulation pipe 73 is connected to a connection part P9 located upstream of the discharge pump 6 of the discharge pipe 7. The downstream end of the extraction pipe 71 is connected to the tank 2. The circulation pipe 73 is equipped with an on-off valve 74 that opens and closes the flow path of the circulation pipe 73, and a heat exchanger 33 located downstream of the on-off valve 74. The on-off valve 74 is opened when the receiving pipe 3 is pre-cooled, and is otherwise closed.
[0031] In the tank equipment 1 according to Modification 2, during the pre-cooling of the receiving pipe 3, the cooling gas 301 heated through the receiving pipe 3 is cooled by heat exchange with the liquefied gas 100 flowing through the circulation pipe 73 in the heat exchanger 33. In other words, a portion of the liquefied gas 100 flowing through the discharge pipe 7 is used to cool the cooling gas 301, while the main flow of liquefied gas 100 flowing through the discharge pipe 7 is not used to cool the cooling gas 301. This makes it possible to suppress the temperature rise of the liquefied gas 100 flowing through the discharge pipe 7.
[0032] [Summary] As explained above, the tank equipment 1 relating to this disclosure is A tank 2 for storing liquefied gas 100 has a liquid inlet 24, a liquid outlet 25, and a gas outlet 26. A receiving pipe 3 is connected to the liquid inlet 24 of tank 2, through which the liquefied gas 100 to be received into tank 2 flows, A discharge pipe 7 is connected to the liquid outlet 25 of tank 2, and through which the liquefied gas 100 discharged from tank 2 flows. A BOG pipe 12 is connected to the gas outlet 26 of tank 2, into which boil-off gas 300 generated by the vaporization of liquefied gas 100 in tank 2 flows, A BOG compressor 14 is located in the BOG piping 12, A cooling gas supply pipe 30 is connected to the upstream portion of the receiving pipe 3 and supplies boil-off gas 300 as cooling gas 301 to the receiving pipe 3 when liquefied gas 100 is not flowing through the receiving pipe 3. A cooling gas discharge pipe 31 is connected to the downstream portion of the receiving pipe 3 and the upstream side of the BOG compressor 14 of the BOG pipe 12, and transports the cooling gas 301 that has flowed through the receiving pipe 3 to the BOG pipe 12. The system is characterized by comprising a heat exchanger 33 located in the cooling gas discharge piping 31, which exchanges heat between the cooling gas 301 and the liquefied gas 100.
[0033] According to the tank equipment 1 with the above configuration, the cooling gas 301, which is heated by cooling the receiving pipe 3, is cooled in the heat exchanger 33 before being sent upstream of the BOG compressor 14 in the BOG pipe 12. As a result, the BOG compressor 14 can compress the cooling gas 301 in the same way as the low-temperature boil-off gas 300 generated in the tank 2, and does not require a special compressor for compressing the cooling gas 301. In addition, the cooling gas 301 used to cool the receiving pipe 3 can be supplied as gas in the same way as the boil-off gas 300.
[0034] Furthermore, in the tank equipment 1 with the above configuration, the heat exchanger 33 may be configured to exchange heat between a portion or all of the liquefied gas 100 flowing through the discharge pipe 7 and the cooling gas 301. Alternatively, a circulation pipe 73 that returns a portion of the liquefied gas 100 flowing through the discharge pipe 7 to the tank 2 may be connected to the discharge pipe 7, and the heat exchanger 33 may be configured to exchange heat between the liquefied gas 100 flowing through the circulation pipe 73 and the cooling gas 301.
[0035] In this way, the heat exchanger 33 can sufficiently cool the cooling gas 301 by utilizing the liquefied gas 100 flowing through the discharge pipe 7 as a cooling source. Furthermore, no special refrigerant is required to cool the cooling gas 301.
[0036] Furthermore, in the tank equipment 1 with the above configuration, the cooling gas supply piping 30 may consist of a return gas piping 15 connected to the gas outlet 26 of the tank 2, and a bypass piping 17 connecting the return gas piping 15 to the upstream portion of the receiving piping 3.
[0037] However, the cooling gas supply piping 30 is not limited to the above, and any configuration that can supply boil-off gas 300 as cooling gas 301 to the receiving piping 3 is acceptable. The cooling gas supply piping 30 may be configured, for example, as piping connecting the BOG piping 12 and the receiving piping 3, or as piping connecting the gas outlet 26 of the tank 2 and the receiving piping 3.
[0038] The foregoing discussions in this disclosure are presented for illustrative and explanatory purposes only and are not intended to limit this disclosure to the forms disclosed herein. For example, in the foregoing detailed description, various features of this disclosure are grouped into a single embodiment for the purpose of streamlining the disclosure. However, some of the features contained herein can be combined into alternative embodiments, configurations, or aspects other than those discussed above. [Explanation of Symbols]
[0039] 1: Tank equipment 2: Tank 3: Receiving piping 7: Discharge piping 12: BOG Piping 14: BOG Compressor 15: Return gas piping 17: Bypass piping 24 :Liquid inlet 25:Liquid outlet 26: Gas outlet 30: Cooling gas supply piping 31: Cooling gas discharge piping 33: Heat exchanger 73: Circulation piping 100: Liquefied gas 200: Vaporized gas 300: Boil-off gas 301: Cooling gas
Claims
1. A tank having a liquid inlet, a liquid outlet, and a gas outlet, for storing liquefied gas, A receiving pipe connected to the liquid inlet of the tank, through which the liquefied gas to be received into the tank flows, A discharge pipe is connected to the liquid outlet of the tank, through which the liquefied gas to be discharged from the tank flows, A BOG pipe is connected to the gas outlet of the tank, into which boil-off gas generated by the vaporization of the liquefied gas in the tank flows, A BOG compressor is placed in the aforementioned BOG piping, A cooling gas supply pipe connected to the upstream portion of the receiving pipe, which supplies the boil-off gas as a cooling gas to the receiving pipe when the liquefied gas is not flowing through the receiving pipe, A cooling gas discharge pipe is connected to the downstream portion of the receiving pipe and the upstream side of the BOG compressor in the BOG pipe, and transports the cooling gas that has flowed through the receiving pipe to the BOG pipe. The system includes a heat exchanger positioned in the cooling gas discharge piping, which exchanges heat between the cooling gas and part or all of the liquefied gas that has flowed out into the discharge piping. Tank facilities.
2. A circulation pipe is connected to the discharge pipe to return a portion of the liquefied gas flowing through the discharge pipe back to the tank. The heat exchanger exchanges heat between the liquefied gas flowing through the circulation piping and the cooling gas. The tank equipment according to claim 1.
3. The cooling gas supply piping includes a return gas piping connected to the gas outlet of the tank, and a bypass piping connecting the return gas piping and the upstream portion of the receiving piping. The tank equipment according to claim 1 or 2.