JP4893928B2 - Method and apparatus for cooling liquefied gas receiving pipe - Google Patents

Description

  The present invention relates to a cooling method and apparatus for a liquefied gas receiving pipe for receiving liquefied gas from a liquefied gas supply source such as an LNG ship tank into a storage tank.

  Natural gas is liquefied in an LNG (Liquid Natural Gas) liquefaction facility. The liquefied LNG is transported to various places by, for example, an LNG ship, and the LNG is sent from the tank of the LNG ship that has berthed to the storage tank on the ground side at the LNG receiving terminal of the transport destination.

FIG. 4 shows a schematic structure of an LNG receiving terminal that sends LNG from a LNG ship berthing to the storage tank 41 on the ground side.
When the loading arm 43 is connected to the LNG ship tank, the LNG is sent to the storage tank 41 through the loading arm 43 and the receiving pipe 45 by the cargo pump in the LNG ship tank.

When the LNG is received from the LNG ship tank to the storage tank 41, the pressure in the LNG ship tank decreases, so that BOG (Boil Off Gas) is returned to the LNG ship tank.
For this purpose, a return gas pipe 47 and a return gas blower 49 provided in the return gas pipe 47 are provided.
One end of the return gas pipe 47 is connected to the return gas arm 51, and the other end is connected to the top of the storage tank 41 and communicates with the inside of the storage tank 41.
The BOG generated by the heat input to the storage tank 41 is returned to the LNG ship tank through the return gas pipe 47 and the return gas arm 51 by operating the return gas blower 49. In this way, the pressure in the LNG ship tank is secured.

In the LNG receiving terminal as described above, LNG is normally received from the LNG ship tank to the storage tank 41 periodically. The time required for one acceptance is about one day, and the acceptance interval is, for example, several days to one week.
When LNG is fed into the receiving pipe 45, the evaporating temperature of LNG is about −162 ° C. at normal pressure, so that the receiving pipe 45 is cooled to this temperature.
On the other hand, when the LNG receiving from the LNG ship tank to the storage tank 41 is not performed, if the receiving pipe 45 is left unattended, the temperature of the receiving pipe 45 rises to around room temperature. Therefore, when the next LNG reception is started in this state, problems such as evaporation of a large amount of liquefied gas and a change in length due to thermal contraction of the reception pipe 45 occur.

  Therefore, conventionally, the receiving pipe 45 is cooled and held during a period when LNG is not received. In order to cool and hold the receiving pipe 45, for example, a forced circulation cooling system and a pressurized injection cooling and holding system are employed.

  In the forced circulation cooling system, as shown in FIG. 5, a circulation pipe 53 having one end communicating with the storage tank 41 below the liquid surface and the other end communicating with the receiving pipe 45 is provided on the circulation pipe 53. The LNG is circulated in the order of the storage tank 41, the circulation pipe 53, the receiving pipe 45, and the storage tank 41 by the pump 55. The receiving pipe 45 is cooled and held by the LNG circulating in this way.

In the pressure injection cooling and holding method, as shown in FIG. 6, after the LNG is received, the on-off valve 56 is closed, and the LNG in the receiving tube 45 is recovered until the liquid level in the receiving tube 45 reaches the center level. Collect in drum 57. That is, by maintaining the liquid level in the receiving pipe 45 at the central level, the contact area between the gas and the liquid is increased to promote the evaporation of LNG so that heat is not stored in the liquid. During this cooling and holding, the vaporized gas generated in the receiving pipe 45 is returned to the storage tank 41 through the gas vent pipe 44 and the return gas pipe 47, and the evaporated LNG is supplied from the discharge pump 59.
In this way, the receiving pipe is held at a low temperature by holding LNG in the receiving pipe in a stable state at all times.

Such a forced circulation cooling method, a pressure injection cooling and holding method, and the like are described in, for example, [Prior Art] in Patent Documents 1 and 2 below.
JP 2001-200996 A "Liquid gas receiving pipe cooling and holding device" Japanese Utility Model Publication No. Hei 6-32900 "Pressure and cooling device for LNG receiving pipe"

However, recently, there is a receiving base in which the interval for receiving LNG from the LNG ship tank to the storage tank is longer than one month. In other words, there is a receiving base in which the LNG receiving suspension period is one month or longer.
In such a receiving terminal, when the above-described forced circulation cooling method and pressure injection cooling and holding method are adopted, a large amount of BOG is generated or power for circulating LNG is wasted. There is.
The techniques disclosed in Patent Documents 1 and 2 are not intended to solve this problem.

  Accordingly, an object of the present invention is to receive liquefied gas from a liquefied gas supply source such as an LNG ship tank through a receiving pipe into a storage tank periodically, and when the liquefied gas receiving interval is long. Provided is a method and an apparatus for cooling a liquefied gas receiving pipe, which can greatly reduce the amount of vaporized gas generated to cool the receiving pipe and can greatly reduce the power for cooling the receiving pipe. There is to do.

According to the reference example, in order to achieve the above object, the cooling method of the receiving pipe for receiving the liquefied gas from the liquefied gas supply source to the storage tank, after the liquefied gas acceptance from the liquefied gas supply source to the storage tank is completed. When receiving again, in preparation for the next reception, the vaporized gas in the storage tank is sent to the receiving pipe to cool the receiving pipe, and then the liquefied gas reception is started through the receiving pipe. A method for cooling the liquefied gas receiving pipe is provided.

In the above method, when the next liquefied gas reception from the liquefied gas supply source to the storage tank is started, the vaporized gas in the storage tank is supplied to the receiving pipe in preparation for the next reception. The receiving pipe is cooled by feeding. Thus, since the receiving pipe is cooled immediately before the start of liquefied gas reception, even if the amount of vaporized gas increases due to cooling of the receiving pipe in preparation for the start of liquefied gas reception, the period during which liquefied gas reception is not performed There is no need to cool the receiving pipe, and no unnecessary vaporized gas is generated in the receiving pipe during this time. Therefore, as a whole, the amount of vaporized gas generated for cooling the receiving pipe can be greatly reduced.
Further, the receiving pipe is cooled by sending gas into the receiving pipe. Therefore, the power required for cooling the receiving pipe can be greatly reduced as compared with the power for feeding the liquid into the receiving pipe as in the prior art.

According to a preferred embodiment of the reference example , when the liquefied gas reception from the liquefied gas supply source to the storage tank is completed, the liquefied gas remaining in the receiving pipe is extracted, and in this state, the receiving pipe is received until the next liquefied gas is received. put

As described above, since the liquefied gas remaining in the receiving pipe is extracted while the liquefied gas is not received (between the receiving and receiving), it is wasted in the receiving pipe during the period when the liquefied gas is not received. Generation of vaporized gas is prevented.
Further, since the receiving pipe is left until the next liquefied gas reception is started, it is not necessary to monitor the receiving pipe, so that the burden on the worker can be reduced.

According to a preferred embodiment of the reference example, the gas pipe connecting the receiving pipe and the storage tank is used to circulate the vaporized gas in the order of the storage tank, the gas pipe, the receiving pipe, and the storage tank, and store from the gas pipe. Spray liquefied gas on the vaporized gas returning to the tank.

  Thus, by circulating the vaporized gas in the order of the storage tank, gas pipe, receiving pipe, and storage tank, the receiving pipe can be cooled and the liquefied gas is sprayed on the vaporized gas returning from the gas pipe to the storage tank. , The vaporized gas can be returned to the storage tank with the temperature lowered

According to a preferred embodiment of the reference example , the liquefied gas is supplied from the storage tank to the receiving pipe after the vaporized gas is sent to the receiving pipe and the receiving pipe is cooled and before the next liquefied gas is started to be received. .

As described above, since the liquefied gas is supplied to the receiving pipe after the vaporized gas is sent to the receiving pipe and before the next liquefied gas reception is started, the receiving pipe is gradually cooled to the temperature of the liquefied gas. be able to.
In addition, after leaving the receiving pipe in the period when liquefied gas is not being received, the receiving pipe that has reached room temperature is gradually cooled by vaporized gas and liquefied gas, so that rapid thermal contraction of the receiving pipe is suppressed. be able to.

According to the present invention, there is also provided a receiving pipe cooling device for receiving liquefied gas from a liquefied gas supply source to a storage tank,
A receiving tube for receiving liquefied gas from a liquefied gas supply source;
A storage tank for storing the liquefied gas by receiving the liquefied gas from the liquefied gas supply source through the receiving pipe;
A gas pipe communicating with the receiving pipe and the gas portion of the storage tank;
A pump for feeding the liquefied gas in the storage tank to a receiving pipe;
A thermometer for measuring the temperature of the receiving pipe;
The cooling gas is circulated in the order of a storage tank, a gas pipe, a receiving pipe, and a storage tank by the blower to cool the receiving pipe, and based on a signal received from the thermometer, When it is determined that the temperature has become a predetermined value or less, a control device that performs control to operate the pump , and
The receiving pipe is in communication with the gas portion of the storage tank;
Furthermore, a cooling device for a liquefied gas receiving pipe, comprising: a blower that circulates vaporized gas in the order of a storage tank, a gas pipe, a receiving pipe, and a storage tank to cool the receiving pipe is provided. .

In the above configuration, the gas pipe communicates with the receiving pipe and the gas part of the storage tank, and the receiving pipe communicates with the gas part of the storage tank, so that the storage tank, the gas pipe, the receiving pipe, and the storage tank are vaporized in this order. A path for circulating the gas can be formed.
Therefore, when receiving the liquefied gas from the liquefied gas supply source to the storage tank using the above apparatus and starting the next liquefied gas reception, the fan is operated in preparation for the next reception. The vaporized gas can be circulated in the order of storage tank, gas pipe, receiving pipe, and storage tank. Thereby, a receiving pipe can be cooled.
By performing such a circulation of the vaporized gas immediately before receiving the next liquefied gas, the receiving pipe can be cooled. Therefore, even if the amount of vaporized gas increases due to the cooling of the receiving pipe in preparation for the start of the next liquefied gas reception, it is not necessary to cool the receiving pipe while the liquefied gas is not being received. Wasteful vaporized gas is not generated in the pipe. Therefore, as a whole, the amount of vaporized gas generated for cooling the receiving pipe can be greatly reduced.
Furthermore, when the receiving pipe is cooled by circulating gas, the receiving pipe is uniformly cooled, and the power required for cooling the receiving pipe is circulated as in the conventional case to cool the receiving pipe. Compared with the power of, it can be greatly reduced.
In addition, since the liquefied gas can be supplied by the pump to the receiving pipe cooled by the vaporized gas before starting the next liquefied gas receiving, the receiving pipe can be cooled stepwise.

  According to a preferred embodiment of the present invention, the apparatus further includes a spraying device that sprays the liquefied gas onto the vaporized gas that is provided in the receiving pipe and returns from the receiving pipe to the storage tank.

  Thus, since the liquefied gas is sprayed on the vaporized gas returning to the storage tank by the spraying device, the vaporized gas can be returned to the storage tank in a state where the vaporized gas is returned to a low temperature.

  Further, according to a preferred embodiment of the present invention, the receiving pipe includes a receiving portion extending from the liquefied gas supply source side toward the storage tank, a rising portion connected to the receiving portion and extending upward, and a rising portion of the rising portion. A connection part connected to the upper part and connected to the gas part of the storage tank, and further comprising a liquid injection pipe connecting the liquid part of the storage tank and the rising part, and the pump is liquefied through the liquid injection pipe Gas is fed into the rising part.

  Thus, the liquid injection pipe which connects the liquid part of a storage tank and the rising part of a receiving pipe is further provided, and the pump sends liquefied gas to the rising part through this liquid injection pipe. Therefore, the liquefied gas sent to the rising portion falls down the rising portion and is sent vigorously to the receiving portion of the receiving pipe. Thereby, the liquefied gas can be efficiently filled into the receiving pipe in preparation for the start of the next liquefied gas reception.

  According to the present invention described above, when the liquefied gas is periodically received from the liquefied gas supply source such as the LNG ship tank to the storage tank via the receiving pipe, and the liquefied gas is not received over a long period of time. In addition, the amount of vaporized gas generated for cooling the receiving pipe can be greatly reduced, and the power for cooling the receiving pipe can be greatly reduced.

  A preferred embodiment of the present invention will be described with reference to the drawings.

First, each configuration of the LNG receiving terminal will be described, and then the liquefied gas receiving pipe cooling device 10 according to the embodiment of the present invention will be described.
FIG. 1 shows a configuration of an LNG receiving terminal including a liquefied gas receiving pipe cooling device 10 according to an embodiment of the present invention.

As a configuration for sending LNG from the LNG ship that has berthed to the storage tank 2, a loading arm 3 that is connected to the tank of the LNG ship and a receiving pipe 5 that connects the loading arm 3 and the storage tank 2 are provided. .
With this configuration, LNG is sent from the LNG ship tank to the storage tank 2 through the loading arm 3 and the receiving pipe 5. At this time, the on-off valves 6 and 14 in FIG. 1 are opened. The LNG ship tank in which LNG as liquefied gas is stored constitutes a liquefied gas supply source. However, the present invention is not limited to this, and the liquefied gas supply source may be constituted by other appropriate ones. Good. In this case, liquefied gas other than LNG may be sent from the liquefied gas supply source to the storage tank 2.

LNG is a liquid having a normal pressure and a boiling point of about −162 ° C., and is always in a boiling state due to intrusion heat. While receiving LNG from the LNG ship tank to the storage tank 2 via the receiving pipe 5, LNG is vaporized in the storage tank 2 due to heat input to the receiving pipe 5 and the storage tank 2, and the LNG evaporates. A certain BOG occurs.
As a configuration for returning this BOG to the LNG ship tank, a return gas pipe 11, a return gas blower 9 provided in the return gas pipe 11, and a return gas arm 13 connecting the return gas pipe 11 and the LNG ship are provided. It is done. The return gas pipe 11 is also connected to the gas portion of the storage tank 2.
With this configuration, the BOG generated in the storage tank 2 is returned to the LNG ship tank through the return gas pipe 11 and the return gas arm 13 by the operation of the return gas blower 9. At this time, in FIG. 1, the on-off valves 18 and 19 are opened, and the on-off valve 21 is closed.

  A liquefied gas receiving pipe cooling device 10 according to an embodiment of the present invention provided in the LNG receiving terminal having the above-described configuration will be described.

The liquefied gas receiving pipe cooling device 10 according to the embodiment of the present invention is configured to reduce the BOG generated to cool the receiving pipe 5 when the period from the end of the LNG reception from the LNG ship tank to the start of the next reception becomes long. The power for cooling the receiving pipe 5 can be greatly reduced by greatly reducing the amount.
For this purpose, the cooling device 10 for the liquefied gas receiving pipe, when the LNG reception from the LNG ship tank to the storage tank 2 is completed and then starts the next LNG reception, the storage tank 2 is prepared for this next reception. The BOG is sent to the receiving pipe 5 to cool the receiving pipe 5, and then the LNG receiving can be started through the receiving pipe 5.
Further, the cooling device 10 for the liquefied gas receiving pipe extracts the LNG remaining in the receiving pipe 5 to the storage tank 2 when the LNG receiving from the LNG ship tank to the storage tank 2 is completed, and the receiving pipe 5 is connected in this state. It is configured so that it can be left until the next LNG acceptance start.

  Hereinafter, a specific configuration of the cooling device 10 for the liquefied gas receiving pipe will be described.

As a configuration for extracting the LNG remaining in the receiving pipe 5 when the LNG reception into the storage tank 2 is completed, a drain pipe 25 connected to the receiving pipe 5 and extending to the storage tank 2, and the drain pipe 25, and a pump 26 provided at 25.
By operating the pump 26, the LNG remaining in the receiving pipe 5 can be extracted through the drain pipe 25 and sent to the storage tank 2. At this time, the on-off valves 29 and 30 are kept open. In addition, you may make it extract LNG remaining in the receiving pipe 5 with another structure.
Therefore, when the LNG acceptance is completed, the LNG in the acceptance pipe 5 can be extracted, so that the LNG remains in the acceptance pipe 5 after the LNG acceptance is completed until the next LNG acceptance is started. The receiving pipe 5 can be left unattended. Therefore, no BOG is generated in the receiving pipe 5 during this period.

In order to cool the receiving tube 5 by sending LNG to the receiving tube 5 in preparation for the start of the reception when the next LNG receiving is started after the LNG is extracted from the receiving tube 5 and left to stand. The following configuration is provided in the cooling device 10 of the liquefied gas receiving pipe.
The cooling device 10 for the liquefied gas receiving pipe includes a receiving pipe 5 for receiving LNG from the LNG ship tank, a storage tank 2 for receiving LNG from the LNG ship tank through the receiving pipe 5, and a receiving pipe 5 and a storage tank for storing LNG. And a gas pipe 28 communicating with the two gas portions. In addition, the receiving pipe 5 communicates with the gas portion of the storage tank 2. In the example of FIG. 1, the gas pipe 28 includes a gas vent pipe 7 and a return gas pipe 11.
Thereby, immediately before starting the LNG acceptance to the storage tank 2, the BOG in the storage tank 2 is circulated in the order of the storage tank 2, the gas pipe 28, the reception pipe 5, and the storage tank 2 to cool the reception pipe 5. be able to. This circulation can be performed by operating the return gas blower 9 as a blower.
This circulation can be performed, for example, by operating the return gas blower 9 with the on-off valves 14, 16, 19 opened and the on-off valves 6, 18, 21, 29 closed.

In order to return the circulating BOG to the storage tank 2 in a state of returning to a low temperature as described above, the following configuration is provided in the cooling device 10 for the liquefied gas receiving pipe.
The liquefied gas receiving pipe cooling device 10 includes a spraying device 32 that is provided in the receiving pipe 5 and sprays LNG onto the BOG that returns from the receiving pipe 5 to the storage tank 2. FIG. 2 is an enlarged view of a portion surrounded by a broken line in FIG. The spray device 32 may be, for example, an injection nozzle 32 attached to the tip of a liquid injection pipe 34 (see FIG. 1) as shown in FIG. By opening the on-off valve 36 and operating the pump 35, LNG is supplied to the injection nozzle 32 through the liquid injection pipe 39 and the liquid injection pipe 34 branched from the middle of the liquid injection pipe 39. Sprayed.
While the BOG is being circulated using the spraying device 32, the BOG returned to the storage tank 2 is sprayed with LNG, so that the BOG is returned to a low temperature (for example, −150 ° C.). It can be returned to the storage tank 2.

In order to confirm whether the receiving pipe 5 is sufficiently cooled by circulating the BOG as described above, the liquefied gas receiving pipe cooling device 10 is provided with a thermometer 33 for measuring the temperature of the receiving pipe 5. The thermometer 33 is provided in the receiving pipe 5 and is preferably disposed near the loading arm 3 in the vicinity of the LNG ship tank.
By using this thermometer 33, in preparation for the start of LNG reception, the BOG is circulated in the order of the storage tank 2, the gas pipe 28, the reception pipe 5, and the storage tank 2 as described above, so that the reception pipe 5 is It can be confirmed whether or not a desired temperature (for example, −100 ° C.) or lower is reached.

In order to fill the LNG from the storage tank 2 to the receiving pipe 5 in preparation for the start of LNG receiving into the storage tank 2 after the receiving pipe 5 is sufficiently cooled by the circulation of the BOG described above, the following configuration is used to receive the liquefied gas. A tube cooling device 10 is provided.
The liquefied gas receiving pipe cooling device 10 includes a pump 35 that sends LNG in the storage tank 2 to the receiving pipe 5. The pump 35 mainly pays LNG to a demand point, but branches from the payout line and fills the receiving pipe 5 with LNG in the storage tank 2.
Therefore, after the receiving pipe 5 is left in a period during which no LNG is received, the receiving pipe 5 that has become normal temperature is prepared by circulating the BOG and filling the LNG in preparation for the start of receiving LNG into the storage tank 2. Since the cooling is performed step by step, rapid thermal contraction of the receiving pipe 5 can be suppressed.

When the operation of filling LNG from the storage tank 2 to the receiving pipe 5 is automatically performed after the receiving pipe 5 is sufficiently cooled by the circulation of the BOG described above, the following configuration is a cooling device 10 for the liquefied gas receiving pipe. Prepared for.
The liquefied gas receiving pipe cooling device 10 receives a signal from the thermometer 33 during the cooling of the receiving pipe 5 by the BOG circulation described above in preparation for the start of LNG reception, and based on this signal, When it is determined that the temperature of the receiving pipe 5 has become equal to or lower than a predetermined value, a control device 37 that performs control to operate the pump 35 is provided. At this time, the control device 37 also sends a signal to the on-off valves 38 and 36 provided in the liquid injection pipe 39 to perform control to open the on-off valve 38 and close the on-off valve 36.
By this control, when the control device 37 determines that the temperature of the receiving pipe 5 has become a predetermined value (for example, −100 ° C.) or less, the pump 35 is operated, so that the receiving pipe 5 is automatically cooled sufficiently by the BOG. After that, LNG can be supplied to the receiving pipe 5. Thereby, the amount of BOG generated in the receiving pipe 5 can be minimized when the LNG is received and filled from the storage tank 2 into the receiving pipe 5 in preparation for the start of LNG reception.

In order to efficiently fill the receiving pipe 5 with LNG in preparation for the start of LNG reception, the following configuration is provided.
The receiving pipe 5 includes a receiving portion 5a extending from the loading arm 3 on the LNG ship tank side toward the storage tank 2, a rising portion 5b connected to the receiving portion 5a and extending upward, and an upper portion of the rising portion 5b. And a connecting portion 5c connected to the gas portion of the storage tank 2. Further, the liquid injection tube 39 connects the liquid portion of the storage tank 2 and the rising portion 5b. The pump 35 is provided in the liquid injection pipe 39, and sends LNG through the liquid injection pipe 39 to the rising portion 5b.
Thus, the pump 35 sends LNG to the rising portion 5b through the liquid injection tube 39. Accordingly, the LNG sent to the rising portion 5b falls down the rising portion 5b and is sent to the receiving portion 5a of the receiving pipe 5 with a high force.

  Next, a cooling method of the liquefied gas receiving pipe by the liquefied gas receiving pipe cooling apparatus having the above-described configuration will be described with reference to FIG.

  In step S1, when the LNG reception from the LNG ship tank to the storage tank 2 is completed, the on-off valves 29 and 30 are opened, the pump 26 is operated, and the LNG remaining in the reception pipe 5 is sent to the storage tank 2, LNG in the receiving pipe 5 is extracted. After extraction, the on-off valves 29 and 30 are closed. This draining is performed, for example, over about 12 hours.

  Subsequently, in step S2, the receiving pipe 5 is left until the next LNG receiving from the LNG ship tank to the storage tank 2 is started. During this time, since no LNG remains in the receiving pipe 5, it is possible to prevent useless BOG from occurring in the receiving pipe 5. The period during which LNG is not accepted is, for example, about 30 days or more.

  Next, in the case where the next LNG reception is started in step S3, in preparation for the start of the reception, the on-off valves 19, 16, 14 are opened, the on-off valve 21 is closed, the return gas blower 9 is operated, and the BOG is operated. The storage tank 2, the gas pipe 28, the receiving pipe 5, and the storage tank 2 are circulated in this order. Thereby, the receiving pipe 5 is cooled. The receiving pipe 5 is cooled, for example, over about 16 hours. At this time, LNG is sprayed from the spraying device 32 (see FIG. 2), so that the BOG is lowered to a low temperature (for example, −150 ° C. or lower) and returned to the storage tank 2.

  Subsequently, when the control device 37 determines in step S4 that the temperature of the receiving pipe 5 has become equal to or lower than a desired temperature (for example, −100 ° C.) based on the temperature signal from the thermometer 33, the process proceeds to step S5. .

In step S <b> 5, the control device 37 opens the on-off valve 38 to inject LNG from the storage tank 2 to the rising portion 5 b of the receiving pipe 5. Thereby, the LNG is filled in the receiving pipe 5 in preparation for the start of LNG reception. This LNG filling is performed, for example, over about 5 hours.
The determination of the completion of the LNG filling is made by confirming that the temperature measured by the thermometer 33 is −160 ° C. or lower, or by measuring the liquid level with a liquid level detecting device such as a differential pressure gauge provided in the receiving pipe 5. It can be done by checking. In other words, for example, when the control device 37 determines that the temperature of the receiving pipe 5 is equal to or lower than a predetermined value (in this example, −160 ° C. or lower) based on the signal received from the thermometer 33, the control device 37 returns to the on-off valve 38. A control signal is sent to close the on-off valve 38. When the LNG filling is completed, the process proceeds to step S6.
The BOG generated by filling the LNG into the receiving pipe 5 can be sent to the BOG compressor 40 in FIG. 1 and compressed, and then sent to a predetermined demand point.

  In step S <b> 6, LNG reception from the LNG ship tank to the storage tank 2 is started through the reception pipe 5, and LNG is received into the storage tank 2. This LNG acceptance is performed, for example, over about 12 hours. Then, it returns to step S1.

As described above, according to the cooling apparatus and method for the liquefied gas receiving pipe according to the embodiment of the present invention, when the LNG reception from the LNG ship tank to the storage tank 2 is completed and then the LNG reception is started, the acceptance is started. The receiving pipe 5 is cooled by sending the BOG in the storage tank 2 to the receiving pipe 5. As described above, since the receiving pipe 5 is cooled immediately before the start of LNG reception, even if the amount of BOG increases due to cooling of the receiving pipe 5 in preparation for the start of LNG reception, There is no need for cooling, and no wasteful BOG is generated in the receiving pipe 5 during this time. Therefore, as a whole, the amount of BOG generated for cooling the receiving pipe 5 can be greatly reduced.
Further, in the present embodiment, the receiving pipe 5 is cooled by sending BOG, which is a gas, into the receiving pipe 5. Therefore, the power required for cooling the receiving pipe 5 can be greatly reduced as compared with the power for feeding the liquid into the receiving pipe 5 as in the prior art.

  In addition, this invention is not limited to embodiment mentioned above, Of course, a various change can be added in the range which does not deviate from the summary of this invention.

It is a figure which shows the cooling device of the liquefied gas receiving pipe by embodiment of this invention. It is an enlarged view of the part enclosed with the broken line of FIG. 1, and has shown the spraying apparatus. It is a flowchart which shows the cooling method of the liquefied gas acceptance pipe | tube by embodiment of this invention. It is a figure which shows schematic structure of an LNG receiving base. It is explanatory drawing of the forced circulation cooling system used for the cooling holding | maintenance of the receiving pipe in an LNG receiving base. It is explanatory drawing of the pressurization injection cooling holding | maintenance system used for cooling holding | maintenance of the receiving pipe in an LNG receiving base.

Explanation of symbols

2 storage tank 3 loading arm 5 receiving pipe 5a receiving part 5b rising part 5c connecting part 7 degassing pipe 9 return gas blower (blower)
10 Cooling and holding device 11 for liquefied gas receiving pipe Return gas pipe 11
13 Return gas arm 14, 16, 18, 19, 21, 22 On-off valve 25 Drain pipe 26 Pump 28 Gas pipe 32 Spraying device 33 Thermometer 34 Liquid injection pipe 35 Pump 36 On-off valve 37 Controller 38 On-off valve 39 Liquid injection pipe 40 BOG compressor

Claims (3)

A receiving pipe cooling device for receiving liquefied gas from a liquefied gas supply source into a storage tank,
A receiving tube for receiving liquefied gas from a liquefied gas supply source;
A storage tank for storing the liquefied gas by receiving the liquefied gas from the liquefied gas supply source through the receiving pipe;
A gas pipe communicating with the receiving pipe and the gas portion of the storage tank;
A pump for feeding the liquefied gas in the storage tank to a receiving pipe;
A thermometer for measuring the temperature of the receiving pipe;
The cooling gas is circulated in the order of a storage tank, a gas pipe, a receiving pipe, and a storage tank by the blower to cool the receiving pipe, and based on a signal received from the thermometer, When it is determined that the temperature has become a predetermined value or less, a control device that performs control to operate the pump , and
The receiving pipe is in communication with the gas portion of the storage tank;
A cooling device for a liquefied gas receiving pipe, further comprising a blower for circulating the vaporized gas in the order of a storage tank, a gas pipe, a receiving pipe, and a storage tank to cool the receiving pipe. Wherein provided in the receiving tube, liquefied gas receiving tube of the cooling device according to claim 1, the spraying device for spraying the vaporized gas in the liquefied gas returning from the receiving tube to the storage tank, and further comprising. The receiving pipe is connected to the receiving portion extending from the liquefied gas supply side toward the storage tank, the rising portion connected to the receiving portion and extending upward, and the upper portion of the rising portion connected to the gas portion of the storage tank. A connecting portion, and
A liquid injection pipe connecting the liquid portion of the storage tank and the rising portion;
2. The cooling device for a liquefied gas receiving pipe according to claim 1 , wherein the pump feeds the liquefied gas to the rising portion through the liquid injection pipe.

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