JP5077881B2 - Facility for receiving liquefied natural gas - Google Patents

Description

The present invention relates to a receiving facility for receiving LNG from a transport device such as a tank lorry in an LNG storage tank provided in a small LNG (liquefied natural gas) base. In particular, the LNG receiving facility of the present invention is suitable for receiving LNG from a so-called two-port tank lorry.

  Conventionally, a relatively small satellite base is generally installed in an LNG demand area away from a primary receiving base that first receives LNG. The satellite base includes a storage tank for storing LNG and a receiving facility for receiving LNG from a tank lorry or the like to the storage tank. When LNG is received from the tank lorry to the storage tank, it is necessary to maintain the tank pressure in the tank lorry at a relatively high level. Therefore, the tank lorry has a self-pressurization method (1 Mouth specification) exists. On the other hand, due to the recent demand for larger tank capacity, a non-self-pressurization method that transfers LNG using a pump, compressor, etc. installed in the satellite base receiving facility without installing a pressurized evaporator or the like Tank lorries (two-port or three-port specifications) are becoming mainstream. In particular, the two-port tank lorry can hold the differential pressure with the LNG storage tank more stably than the three-port specification, and it is more powerful because it has better operability and reproducibility. is there. When receiving LNG, it is necessary to keep the pressure in the LNG storage tank relatively low, so the satellite base receiving facility is equipped with a compressor for discharging BOG (boil-off gas) There is.

Regarding the acceptance of LNG at such satellite bases, for example, in the LNG supply system, when LNG is received from the tank lorry into the LNG storage tank, BOG (boil-off gas) discharged from the LNG storage tank is supplied to the tank lorry. The pressure in the tank lorry is decreased and the pressure in the tank lorry is increased, and then the LNG in the tank lorry is boosted by a lorry pressurizer and the LNG is supplied to the storage tank. (See Patent Document 1).
Japanese Patent Laid-Open No. 2007-132490

  In the above prior art, since the BOG discharged to lower the pressure in the LNG storage tank is used for boosting the tank lorry, the pressure of the LNG storage tank and the tank lorry can be temporarily adjusted by effectively using the BOG. Become. However, since the supply of LNG from the tank lorry to the LNG storage tank thereafter requires a pressurizer for lorries (such as a low-temperature pump for LNG), the equipment cost increases, and the running cost due to the power consumption of the pressurizer In addition, there is a problem in that operations such as cooling down and venting of piping around the pressurizer are required at the time of acceptance.

  Also, in the above prior art, the satellite base has two LNG storage tanks. In such a case, without using the pressurizer, the pressure of one LNG storage tank is increased and used to pressurize the tank truck. A method of receiving LNG by lowering the pressure of the other LNG storage tank is also conceivable. However, in this case, since it is necessary to improve the pressure resistance so that both of the two LNG storage tanks can be used for pressurization, there is a problem that the equipment cost increases. Further, when the frequency of receiving LNG from the tank lorry increases, it is necessary to switch between the receiving side and the pressurizing side (pressurization and depressurization) in a short time, and there is a problem that the operation operation becomes complicated. Furthermore, it cannot be applied to a satellite base that is smaller and has only one LNG storage tank. Conventionally, when one LNG storage tank is used, a tanker lorry is equipped with a pressure evaporator for lorry pressurization. And accepting LNG. However, by installing a pressurized tank on the tank lorry, the load capacity of LNG was limited, and it was obliged to carry high-pressure gas licensed earners.

The present invention has been devised to solve such problems of the prior art. The purpose of the present invention is to store LNG from a non-self-pressurized transport device (such as a tank lorry) in a small LNG base. An object of the present invention is to provide an LNG receiving facility capable of receiving LNG into a tank with a simple facility at low cost.

  A first invention made to solve the above-described problem is a receiving facility for receiving LNG from a transport device in a storage tank provided in the LNG base, and is a pressurization facility for pressurizing LNG in the transport device. A tank for pressurizing LNG, a circulation line connecting a liquid phase part and a gas phase part of the tank for pressurization, and LNG provided on the circulation line and led from the liquid phase part of the tank for pressurization A pressure evaporator for evaporating the pressure, a pressure line from the gas phase part of the pressure tank to the transport device, a transfer line from the transport device to the storage tank, the pressure tank and the storage A tank connection line connecting the tank, the pressurizing tank has a smaller capacity than the storage tank, and the storage of the LNG from the transport device to the storage tank during the storage A structure for receiving the LNG supply of pressurization required the transfer from tank.

  According to this, boosters (pumps, compressors, etc.) to pressurize LNG in the transporting device, accepting LNG from non-self-pressurizing transporting devices (tank lorries, etc.) to storage tanks at small LNG bases It can be carried out at low cost with simple equipment without using.

  According to a second aspect of the present invention, the tank connection line includes: a supply line that connects a liquid phase part of the storage tank and a liquid phase part of the pressurization tank; A pressure equalizing line connecting a phase part and a gas phase part of the pressurization tank, wherein the pressurization tank is separated from the storage tank by a difference in head pressure between the pressurization LNG and the LNG of the storage tank. It can be set as the structure provided so that it might be supplied.

  According to this, LNG can be easily supplied from the storage tank to the pressurizing tank without requiring a transport device such as a pump.

  According to a third aspect of the present invention for solving the above-described problem, the pressure equalizing line has a configuration in which an opening end on the pressurizing tank side is disposed at a liquid surface upper limit position of the pressurizing LNG in the pressurizing tank. It can be.

  According to this, since the liquid level of the LNG in the pressurizing tank can be prevented from exceeding a preset upper limit position, an apparatus for adjusting the position of the liquid level (that is, the capacity of the pressurizing LNG) (for example, A required amount of LNG can be supplied to the pressurizing tank without requiring a liquid level adjuster) or an operation (for example, opening and closing of a regulating valve for maintaining a desired liquid level position).

  A fourth invention made to solve the above-mentioned problems is a pressure adjustment line connected to the gas phase part of the pressurizing tank for adjusting the pressure in the tank by discharging gas, and the pressure from the storage tank. When the pressurizing LNG is supplied to the pressure tank, it is possible to further include a communication line that communicates the pressure adjustment line and the pressure equalization line.

  According to this, when LNG is supplied to the pressurizing tank, the gas in the tank can be discharged at least temporarily to a pressure adjustment line whose pressure is lower than that of the storage tank. It can be done promptly.

  According to a fifth aspect of the present invention made to solve the above-described problem, the pressurizing evaporator is configured such that the pressurizing LNG is supplied from the pressurizing tank by a head pressure difference from the LNG of the pressurizing tank. It can be set as the structure provided.

  According to this, LNG can be easily supplied from the pressurization tank to the pressurization evaporator without requiring a transport device such as a pump.

  As described above, the present invention uses a booster for pressurizing LNG in a transport device for accepting LNG from a non-self-pressurized transport device (such as a tank lorry) to an LNG storage tank in a small LNG base. The present invention has an excellent effect that it can be performed at low cost with simple equipment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a configuration diagram schematically showing a satellite base equipped with an LNG receiving facility according to the present invention. This satellite base 1 is a relatively small receiving base provided in the LNG demand area away from the LNG primary receiving base, and an LNG storage tank 2 for storing the LNG and an LNG storage tank 2 to the LNG Is mainly provided with a payout facility 3 for paying out LNG to a payee (customer) and a receiving facility 5 for receiving LNG from the tank truck 4 in the LNG storage tank 2.

  The LNG storage tank 2 is a well-known LNG storage tank having an LNG cooling function. The LNG storage tank 2 may be of any container type (vertical type or horizontal type), but by adopting a vertical type, a difference in head pressure (liquid level) can be easily achieved with a small-pressure tank as described later. Difference in height), and it is advantageous in that the supply of LNG to the pressurizing tank is facilitated.

  The payout facility 3 includes a BOG (boil-off gas) line 11 composed of piping from the gas phase part G1 of the LNG storage tank 2 to the payout destination, a BOG warmer 12 provided on the BOG line 11, and an LNG storage tank. A discharge line 13 composed of a pipe from the second liquid phase portion L1 to the discharge destination, and an LNG vaporizer 14 provided on the discharge line 13. The payout equipment 3 causes the BOG generated in the LNG storage tank 2 to be heated toward the payout destination after being heated by the BOG heater 12, and the LNG stored in the LNG storage tank 2 is transferred to the LNG vaporizer 14. After being vaporized, it is sent to the payee.

  The tank lorry 4 is a well-known transport device including a tank 15 for transporting LNG from the primary receiving base to the satellite base 1. The tank lorry 4 is not equipped with means for pressurizing the LNG in the tank 15 (pressure evaporator, etc.), and as will be described later, the LNG in the tank 15 is stored in LNG by pressurization from the receiving facility 5. It is transferred to the tank 2. In addition, as a transport apparatus used for conveyance of LNG, it is not necessarily limited to a tank truck, Other vehicles, ships, etc. provided with the same conveyance function may be used.

  The receiving facility 5 includes a pressurizing tank 21 for storing pressurizing LNG used for pressurizing the LNG in the tank lorry 4, and a pipe connecting the liquid phase portion L2 and the gas phase portion G2 of the pressurizing tank 21. A circulation line 22, a pressure evaporator 23 provided on the circulation line 22, a pressure line 24 including a pipe extending from the gas phase portion G 2 of the pressurization tank 21 to the tank truck 4 through the circulation line 22, A transfer line 25 consisting of piping from the tank lorry 4 to the LNG storage tank 2, a supply line 26 consisting of piping connecting the liquid phase part L2 of the pressurizing tank 21 and the liquid phase part L1 of the LNG storage tank 2, and a pressurizing line A pressure equalizing line 27 composed of a pipe connecting the gas phase portion G2 of the tank 21 and the gas phase portion G1 of the LNG storage tank 2, and the BO of the discharge facility 3 from the gas phase portion G2 of the pressurizing tank 21. And a pressure adjustment line 28 of the pipe leading to the line 11.

  The pressurizing tank 21 is composed of, for example, a double-shell vacuum adiabatic storage tank, and has a very small capacity (for example, 1 kiloliter) compared to the capacity of the LNG storage tank (for example, 150 kiloliter). The capacity of the pressurizing tank 21 can be set to a size that can accommodate the LNG for pressurization having a capacity necessary for receiving the LNG from one tank lorry 4 to the LNG storage tank 2. By setting the pressure tank 21 to the minimum necessary capacity, the equipment cost can be greatly reduced. The pressurizing tank 21 is supported at a position (for example, the top is 5 m above the ground) lower than the position of the LNG storage tank 2 (for example, the top is 20 m above the ground) by a gantry (not shown). As a result, LNG can be supplied from the LNG storage tank 2 to the pressurizing tank 21 due to a difference in head pressure from the LNG storage tank 2 as will be described later.

  The circulation line 22 includes an upstream portion 33 that extends from the bottom of the pressurizing tank 21 to the pressurizing evaporator 23, and a downstream portion 32 that extends from the pressurizing evaporator 23 to the top of the pressurizing tank 21. The pressure evaporator 23 is an air temperature type vaporizer, and is led from the upstream portion 33 of the circulation line 22 due to the difference in head pressure between the pressure tank 21 and the pressure evaporator 23 (the difference in liquid level). LNG is evaporated under pressure and sent to the downstream portion 32. NG (vaporized gas) in the downstream portion is returned to the pressurizing tank 21 again, and the pressure in the pressurizing tank 21 is increased by circulation of this NG. The pressurized evaporator 23 is disposed at a position lower than the pressurizing tank 21, and the LNG in the pressurizing tank 21 is supplied to the pressurized evaporator 23 by the head pressure. With such a configuration, the pressurized evaporator 23 has a mechanism for boosting the LNG of the pressurizing tank 21 without requiring a device such as a pump and the power consumed by the device. The pressure in the pressurizing tank 21 is monitored by the pressure regulator PC.

  A pressurization line 24 is connected to the downstream portion 32 of the circulation line 22, and the pressurization line 24 reaches a pressurization connection port provided in the upper part of the tank 15 of the tank truck 4. The pressurization line 24 only needs to introduce at least the NG of the pressurization tank 21 to the tank lorry 4. For example, the gas phase part of the pressurization tank 21 does not pass through the circulation line 22 (downstream part 32). You may arrange | position so that G2 and the connection port for pressurization of the tank 15 may be connected directly.

  The transfer line 25 extends from the transfer connection port provided in the lower part of the tank 15 of the tank lorry 4 to the gas phase part G1 and the liquid phase part L1 of the LNG storage tank 2.

  The supply line 26 supplies the LNG in the LNG storage tank 2 to the pressurization tank 21 due to the difference in head pressure between the LNG in the LNG storage tank 2 and the LNG in the pressurization tank 21 (liquid level difference). belongs to. When the LNG is supplied, the pressure in the LNG storage tank 2 and the pressurizing tank 21 is maintained uniformly by the pressure equalizing line 27.

  Next, details of a method for receiving LNG from the tank truck 4 in the LNG storage tank 2 in the satellite base 1 will be described. When LNG is received, filling of the pressurizing tank 21 by the LNG supply from the LNG storage tank 2 (preparation mode), pressurization of the pressurization tank 21 by the pressurization evaporator 23 (pressurization mode), and the tank lorry 4 Four operation modes are sequentially executed: transfer of LNG to the LNG storage tank 2 (transfer mode) and release of pressure of the tank lorry 4 and the like after completion of transfer (end mode).

  FIG. 2 is an explanatory diagram of a preparation mode executed in the LNG receiving facility shown in FIG. When the preparation mode is executed, the on-off valve 41 on the supply line 26 and the on-off valves 42 and 43 on the pressure equalizing line 27 are opened, and the on-off valves 44 and 45 on the circulation line 22 and the adjusting valve 46 on the BOG line 11 are opened. In a state where is closed, the on-off valve 47 on the supply line 26 and the on-off valve 48 on the pressure equalizing line 27 are opened. The operation of each of these valves is executed by an electric or fluid pressure operation based on an instruction from a control device (not shown) or manually by an operator (hereinafter, the same applies to other operation modes). As a result, the LNG in the LNG storage tank 2 flows into the pressurization tank 21 through the supply line 26 due to the difference in head pressure, and is filled as pressurization LNG necessary for execution of the transfer mode described later (in FIG. 2). , See thick solid line with arrows). At this time, the liquid level of LNG in the pressurizing tank 21 displayed by the liquid level gauge LG rises from the lower limit position L to the upper limit position H. Further, the pressure in the pressurizing tank 21 is maintained at the same level as the LNG storage tank 2 (for example, 0.3 MPa) when the gas in the tank 21 flows into the LNG storage tank 2 through the pressure equalizing line 27. (See the thick broken line with an arrow in FIG. 2).

  Here, the pipe on the pressurizing tank 21 side in the pressure equalizing line 27 is inserted from the top of the tank into the tank and extends downward, and the opening end thereof is arranged so as to coincide with the upper limit position H of the LNG in the tank 21. ing. With such a configuration, the LNG reaching the upper limit position H of the pressurizing tank 21 is returned to the LNG storage tank 2 side again via the pressure equalizing line 27, and the liquid level can be easily prevented from exceeding the upper limit position. can do. That is, a device for adjusting the position of the liquid level (that is, the volume of the LNG for pressurization) (for example, a liquid level regulator) and an operation (for example, opening and closing of a regulating valve for maintaining a desired liquid level position) The required amount of LNG can be filled in the pressurizing tank 21 without the need for the above.

  Further, a communication line 52 is provided between the pressure equalization line 27 and the pressure adjustment line 28, and these can be communicated by opening the valve 49. When executing the above-described preparation mode, the gas in the pressurizing tank 21 is lower than the LNG storage tank 2 from the pressure equalizing line 27 through the communication line 52 by opening the valve 49 at least temporarily. It is possible to guide to a pressure adjustment line 28 that is at a pressure (for example, 0.1 MPa) (see a thick two-dot chain line with an arrow in FIG. 2). In this way, by introducing the gas in the pressurization tank 21 to the pressure adjustment line 28, compared with the case where the gas in the tank 21 as described above flows into the LNG storage tank 2, the pressurization is performed from the LNG storage tank 2. The supply of LNG to the tank 21 can be performed more promptly. The gas in the pressurizing tank 21 guided to the pressure adjustment line 28 is sent to the payout destination after being heated by the BOG heater 12.

  FIG. 3 is an explanatory diagram of a boosting mode executed in the LNG receiving facility shown in FIG. When the filling of the LNG into the pressurizing tank 21 is completed in the preparation mode, the pressurizing mode is subsequently executed. When executing the pressure increase mode, the on-off valves 44 and 45 on the circulation line 22 are opened with the on-off valve 47 on the supply line 26 and the on-off valve 48 on the pressure equalizing line 27 closed. As a result, the LNG in the pressurization tank 21 is supplied to the pressurization evaporator 23 via the upstream portion 33 of the circulation line 22 by the head pressure, and the generated vaporized gas is again supplied to the pressurization tank 21 via the downstream portion 32. Returned and circulated (see thick solid line with arrow in FIG. 3). At this time, the pressure in the pressurizing tank 21 is increased from a pressure similar to that of the LNG storage tank 2 (for example, 0.3 MPa) to a set pressure (for example, 0.6 MPa) necessary for execution of the subsequent transfer mode. . After the pressure in the pressurizing tank 21 reaches the set pressure, the pressure is appropriately maintained by controlling the pressure regulating valve 51 on the pressure regulating line 28 with the pressure regulator PC. Such a step-up operation is continuously executed even when the next transfer mode is entered.

  When this pressure increase mode is executed, a bypass line 52 extending from the gas phase portion of the tank 15 of the tank lorry 4 to the transfer line 25 is provided to close the on-off valve 53 on the transfer line 25, By opening the open / close valve 54 and the open / close valve 55 on the transfer line 25, the line from the circulation line 22 to the LNG storage tank 2 through the tank truck 4 can be communicated. Thereby, in the pressure | voltage rise mode, the low temperature gas of the circulation line 22 can be flowed through the pressurization line 24 and the transfer line 25, and the piping can be cooled down. The valves 54 and 55 may be either automatic valves or manual valves.

  FIG. 4 is an explanatory diagram of a transfer mode executed in the LNG receiving facility shown in FIG. When the pressurization mode completes the pressurization of the pressurizing tank 21 and the cool-down of the transfer line 25, the transfer mode is subsequently executed. When executing the transfer mode, the open / close valve 54 on the pressurization line 24 is opened with the open / close valves 43, 50, 53, 55 on the transfer line 25 and the open / close valve 56 on the pressurization line 24 being opened. . Thereby, NG (for example, vaporized gas having a pressure of 0.6 MPa) of the pressurized tank 21 that has been pressurized flows into the tank 15 via the pressure line 24 (see the thick solid line with an arrow in FIG. 4), The gas phase portion in the tank 15 is pressurized and sent to the transfer line 25 (see the thick broken line with an arrow in FIG. 4). The pressurization of the pressurization tank 21 by NG is continued until all the LNG in the tank 15 is transferred to the LNG storage tank 2 via the transfer line 25. At this time, when the amount of LNG in the tank 15 of the tank truck 4 becomes small, the valve 45 and the valve 56 on the pressurization line 24 are closed to stop pressurization, and the residual pressure in the tank 15 The remaining LNG can be transferred to the LNG storage tank 2. After the transfer of LNG is completed, the pressure in the tank 15 can be lowered to an appropriate value by equalizing the gas phase portions of the tank 15 of the tank truck 4 and the LNG storage tank 2.

  In addition, the transfer of LNG from the tank truck 4 to the LNG storage tank 2 can be performed through one line on the valve 43 side or the valve 50 side, or both lines. At this time, the pressure in the LNG storage tank 2 can be adjusted by adjusting the opening of the valve 50. In this case, the pressure in the LNG storage tank 2 can be reduced by increasing the LNG flow rate on the valve 43 side by adjusting the opening of the valve 50, while increasing the LNG flow rate on the valve 50 side. The pressure in the LNG storage tank 2 can be increased.

  FIG. 5 is an explanatory diagram of an end mode executed in the LNG receiving facility shown in FIG. When the transfer of LNG from the tank truck 4 to the LNG storage tank 2 is completed in the transfer mode, the end mode is subsequently executed. At this time, the pressurizing tank 21 is substantially empty, and the liquid level of the LNG is at the lower limit position L. When executing the end mode, the pressure regulating valve 51 is opened with the on-off valve 44 on the circulation line 22 and the on-off valve 55 on the transfer line 25 being closed. Thereby, the tank 15 of the tank lorry 4 communicates with the pressurization line 24, the downstream portion 32 of the circulation line 22, the pressurization tank 21, the pressure adjustment line 28, and the BOG line 11. Thereby, the residual gas in the tank 15 is released through these lines (see the thick solid line with an arrow in FIG. 5), and the pressure in the tank 15 of the tank lorry 4 is reduced to an appropriate value (for example, 0.3 MPa). be able to. Note that a new route from the pressurization line 24 to the upstream side of the BOG warmer 12 may be provided instead of the residual gas escape route shown in FIG.

  By sequentially executing each operation mode in this manner, LNG can be received from the tank truck 4 to the LNG storage tank 2. The preparation mode can be executed when it is necessary to receive LNG from the tank truck 4 to the LNG storage tank 2, but in some cases, the preparation mode is executed immediately after the end mode. The pressurizing tank 21 can also be filled. Accordingly, there is no need to cool down the piping to be used again, and there is an advantage that LNG can be received from the next tank lorry 4 even when all the LNG in the LNG storage tank 2 has been paid out.

Configuration diagram of a satellite base equipped with an LNG receiving facility according to the present invention Explanatory drawing of the preparation mode performed with the receiving equipment of LNG of FIG. Explanatory drawing of the pressure | voltage rise mode performed with the receiving facility of LNG of FIG. Explanatory drawing of the transfer mode executed by the LNG receiving facility in FIG. Explanatory drawing of the end mode executed by the LNG receiving facility of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Satellite base 2 LNG storage tank 3 Discharge equipment 4 Tank lorry 5 Receiving equipment 21 Pressurization tank 22 Circulation line 23 Pressurization evaporator 24 Pressurization line 25 Transfer line 26 Supply line 27 Pressure equalization line G1, G2 Gas phase part L1, L2 Liquid phase part

Claims (3)

A receiving facility for receiving liquefied natural gas from a transportation device in a storage tank provided in the liquefied natural gas base,
A pressurizing tank for storing liquefied natural gas for pressurization for pressurizing the liquefied natural gas in the transport device;
A circulation line connecting the liquid phase part and the gas phase part of the pressurizing tank;
A pressure evaporator provided on the circulation line and configured to pressurize and evaporate liquefied natural gas introduced from a liquid phase part of the pressurizing tank;
A pressurization line from the gas phase part of the pressurization tank to the transport device;
A transfer line from the transport device to the storage tank;
A supply line connecting the liquid phase part of the storage tank and the liquid phase part of the pressurizing tank;
A pressure equalization line connecting the gas phase portion of the storage tank and the gas phase portion of the pressurizing tank;
A pressure adjusting line connected to the gas phase part of the pressurizing tank and adjusting the pressure in the tank by discharging gas;
A communication line that communicates the pressure adjustment line and the pressure equalization line when the pressurized liquefied natural gas is supplied from the storage tank to the pressurization tank ;
The pressurization tank has a smaller capacity than the storage tank, and supply of liquefied natural gas for pressurization necessary for the transfer from the storage tank when the liquefied natural gas is transferred from the transport device to the storage tank. Receiving facility for liquefied natural gas, 2. The liquefied natural gas according to claim 1 , wherein the pressure equalizing line has an opening end on the pressurizing tank side disposed at a liquid surface upper limit position of the liquefied natural gas for pressurization in the pressurizing tank. Receiving facilities. 2. The pressurized evaporator is provided so that the pressurized liquefied natural gas is supplied from the pressurized tank due to a head pressure difference from the liquefied natural gas in the pressurized tank. Or the receiving facility of the liquefied natural gas of Claim 2 .

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