JP2003014197A - Receiving piping cooling down method for lng satellite equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a LNG unloading time and to improve its efficiency in LNG satellite equipment using one of a pair of LNG tanks as a discharging tank and the other as a receiving tank. SOLUTION: This LNG satellite equipment is provided with receiving piping for receiving LNG from a LNG lorry to the respective LNG tanks, discharging piping for discharging LNG from the respective LNG tanks, and returning piping for returning the LAG discharged to the respective discharging pipes to the receiving piping. Within a predetermined time before arrival of the LNG lorry, the LNG is discharged from one LNG tank serving as the discharging tank to the discharging piping. When the discharged LNG is let flow into the other LNG tank serving as the receiving tank via the returning piping and the receiving piping, the receiving piping is cooled down previously.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an LNG satellite facility configured to receive liquefied natural gas (LNG) in an LNG tank, store it at a cryogenic temperature, and discharge it from the LNG tank as needed. More specifically, it relates to a method for cooling down a receiving pipe used for receiving LNG.

[0002]

2. Description of the Related Art Recently, small-scale LNG satellite facilities of this type are provided in various locations inland as compared with large-scale LNG storage facilities provided in ports. Therefore, in LNG satellite equipment, LNG transported from large-scale LNG storage equipment etc. using LNG truck is
Unloaded to G tank. Generally, LNG supplied from LNG Lori is LN to the LNG satellite equipment.
A receiving pipe for receiving the G tank is provided. Here, the LNG tank is always kept at an extremely low temperature, whereas the receiving pipe is often left at room temperature. Therefore, if unloading of LNG is started from room temperature,
The cryogenic LNG supplied from the NG truck is heated in the receiving pipe before being received in the LNG tank, which causes a problem of lowering the LNG receiving efficiency for the LNG tank.

Therefore, in the conventional LNG satellite equipment, the LNG supplied from the LNG truck is used for unloading.
One of the countermeasures was to gradually cool down the receiving piping by using the cold heat of.

However, the cooling down of the receiving pipe at the time of unloading has the following problems. For one thing, in order to cool down the receiving pipe, it takes an extra 5 to 10 minutes to unload the LNG. Secondly, the internal pressure of the LNG tank rises due to the LNG vaporized gas generated during the cool down, and the time required for unloading the LNG is prolonged. This is because the unloading of LNG is performed by utilizing the differential pressure between the pressure applied by the LNG lorry and the internal pressure of the LNG tank, so the increase in the internal pressure of the LNG tank reduces the differential pressure, and This is because the acceptance efficiency is reduced. In this way, if the receiving piping is cooled down during the unloading of LNG, the unloading time will be lengthened due to the securing of the cooldown time and the decrease in LNG receiving efficiency, and the workability of unloading will be reduced. Became.

[0005] Here, the "liquefaction natural gas storage tank piping facility" that aims to improve the above-mentioned decrease in workability of LNG unloading as a common problem is a utility model registration No. 3069.
It is disclosed in the registered utility model gazette of No. 391. As shown in FIG. 6, this piping facility has one end connected to the storage tank 51 and the other end provided between the storage tank 51 and the first opening / closing valve 53 in the middle of the supply pipe (reception pipe) 52. A return pipe 55 connected through the two opening / closing valve 54 is provided. Then, the opening / closing operation of the first opening / closing valve 53 and the second opening / closing valve 5
Based on the opening / closing operation of 4, the LNG in the storage tank 51 is returned from the supply pipe 52 to the storage tank 51 via the return pipe 55 so that it can be circulated. With this configuration,
Even when the LNG is not unloaded, the supply pipe 52 is kept in the cool-down state to suppress the temperature rise of the supply pipe 52.

[0006]

However, in the above-mentioned conventional piping equipment, the LNG in the storage tank 51 is stored again through the return pipe 55 from the supply pipe 52 even when the LNG is not unloaded. It is returned to the tank 51 and circulated to maintain the cool-down state. Therefore, boil-off gas (BOG) generated by heating LNG while circulating through the supply pipe 52 and the return pipe 55 becomes a problem. That is, since BOG generated in LNG circulating in the supply pipe 52 and the return pipe 55 is constantly returned to the storage tank 51, the internal pressure of the storage tank 51 rises. Therefore, it is necessary to process the increased internal pressure of the storage tank 51 by some means.

On the other hand, in the present general LNG satellite equipment, a pair of LNG tanks are provided, and one of them is configured to be used alternately as a payout tank and the other as a receiving tank. . Therefore, LNG
Regarding the cooldown of the receiving pipe (supply pipe) for the unloading of the above, it is necessary to assume these receiving tank and the discharging tank, but there has been no proposal for such a cooldown until now.

The present invention has been made in view of the above circumstances, and an object thereof is to use one of a pair of LNG tanks as a delivery tank and the other as a receiving tank for unloading LNG. It is an object of the present invention to provide a receiving pipe cooldown method for LNG satellite equipment, which enables shortening of time and efficiency of unloading work.

[0009]

In order to achieve the above object, the invention according to claim 1 stores LNG at a low temperature, and one of them is alternately used as a payout tank and the other as a receiving tank. A pair of LNG tanks and LNG
Receiving piping for receiving LNG supplied from Lori into each LNG tank, and LNG from each LNG tank
A method for cooling down an LNG satellite facility's receiving pipe, comprising: a pay-out pipe for paying out the vapor to a vaporizer; and a return pipe for returning the LNG paid out to each pay-out pipe to the receive pipe. Within a predetermined time immediately before the arrival of the loli
The purpose is to cool down the receiving pipe in advance by discharging G to the discharging pipe and flowing the discharged LNG to the other LNG tank serving as a receiving tank through the return pipe and the receiving pipe.

In the LNG satellite equipment of the above-mentioned structure, from the state where both the pair of LNG tanks are full,
LN using one LNG tank as a payout tank
When G is dispensed and the LNG tank becomes almost empty, the LNG tank is used as a receiving tank to wait for LNG from LNG Lori, and this time the other LNG tank is received.
The tank will be used as a dispensing tank. Here, according to the configuration of the above invention, LNG is dispensed from one of the LNG tanks serving as a dispensing tank to the dispensing pipe within a predetermined time immediately before the arrival of the LNG loli, and the dispensed LNG is returned to the return pipe. Also, the receiving pipe is flown to the other LNG tank serving as a receiving tank through the receiving pipe, so that the receiving pipe is cooled down in advance before receiving the LNG from the LNG lorry. Therefore, the cooling down of the receiving pipe is completed before the unloading of the LNG by the LNG lorry starts, so that the unloading time of the LNG is not prolonged due to the cooldown. Also, since the cool down is performed only for the predetermined time immediately before the arrival of the LNG loli, the heating time of the LNG flowing through the return pipe and the receiving pipe is shortened, the generation of BOG is suppressed, and the BOG to the receiving tank is suppressed. Is suppressed.

In order to achieve the above object, the invention according to claim 2 is the invention according to claim 1, wherein the LNG satellite equipment has a BOG sending pipe for sending BOG from each LNG tank, and a receiving pipe. Connected to the BOG delivery pipe, and a depressurizing pipe for releasing the internal pressure of each LNG tank to the receiving pipe. Prior to the cool down, one LNG tank that serves as the receiving tank is connected to the BO pipe.
It is intended to precool down the receiving pipe by extracting G and flowing the extracted BOG to the BOG sending pipe through the depressurizing pipe, the receiving pipe and the connecting pipe.

According to the structure of the above invention, in addition to the operation of the invention described in claim 1, BOG is extracted from one of the LNG tanks serving as a receiving tank prior to the cool down, and the extracted BOG. Is pre-cooled down by flowing into the BOG delivery pipe through the depressurizing pipe, the receiving pipe and the connecting pipe. Therefore, the receiving pipe is cooled stepwise by the pre-cooldown before the cooldown. In addition, BOG from the receiving tank in advance
As a result, the internal pressure of the receiving tank decreases, the differential pressure between the pressure applied by the LNG lorry and the internal pressure during unloading increases, and the flow rate of LNG received in the receiving tank increases. To be

In order to achieve the above object, the invention according to claim 3 stores a pair of LNG tanks which store LNG at a low temperature and one of which is alternately used as a payout tank and the other as a receiving tank. , LNG Lori supplied from Lori to each LNG tank, the receiving pipe, the receiving on-off valve provided in the receiving pipe corresponding to each LNG tank, and the LNG from each LNG tank to the carburetor For the delivery pipe for delivering, the delivery opening / closing valve provided for each delivery pipe corresponding to each LNG tank, the return pipe for returning the LNG delivered to each delivery pipe to the receiving pipe, and the return pipe Equipped with a return on-off valve provided, L
Before the arrival of the NG loli, by selectively opening and closing each receiving on-off valve, each dispensing on-off valve and the return on-off valve, LNG is dispensed from one of the LNG tanks serving as a dispensing tank, and the dispensed LNG is The purpose is to cool down the receiving pipe by flowing a required amount through the return pipe and the receiving pipe to the other LNG tank serving as the receiving tank.

According to the structure of the above invention, by selectively opening and closing each receiving on-off valve, each dispensing on-off valve, and the return on-off valve before the arrival of the LNG lory, one LNG tank serving as a dispensing tank is opened. LNG is dispensed, and the dispensed LNG is flowed through the return pipe and the receiving pipe to the other LNG tank that serves as the receiving tank, so that the receiving pipe is in advance prior to receiving the LNG from the LNG loli. Will be cooled down to. Therefore, LN
Since the cooling down of the receiving piping is completed before the unloading of LNG by G Lori starts, the unloading time of LNG is not prolonged due to the cooldown. Also, LN
Since the cooldown is only performed for a predetermined time immediately before the arrival of G Lori, L flowing through the return pipe and the receiving pipe
The heating time of NG is shortened, the generation of BOG is suppressed,
BOG is prevented from flowing into the receiving tank.

In order to achieve the above-mentioned object, the invention according to claim 4 is the invention according to claim 3, wherein each of the receiving opening / closing valves, each of the dispensing opening / closing valves and the returning opening / closing valve is based on a predetermined control signal. It is a control valve to be controlled, temperature detecting means for detecting the pipe temperature of the receiving pipe, and each receiving on-off valve, each paying on-off valve and the return on-off valve for starting the cool down of the receiving pipe. After controlling the opening / closing, a cooldown control means for controlling the opening / closing of each receiving opening / closing valve, each dispensing opening / closing valve, and the returning opening / closing valve to end the cooldown when the detected pipe temperature reaches a predetermined value. The purpose is to have and.

According to the configuration of the above invention, in addition to the effect of the invention described in claim 3, in order to start and end the cooldown, the opening and closing of each receiving on-off valve, each dispensing on-off valve and the return on-off valve is cool. Since it is automatically controlled by the down control means, it is not necessary to manually operate each on-off valve.

In order to achieve the above object, the invention described in claim 5 is the same as the invention described in claim 3, wherein each LNG is
BOG delivery pipe for delivering BOG from the tank,
A BOG on-off valve provided in each BOG delivery pipe corresponding to each LNG tank, a depressurizing pipe for releasing the internal pressure of each LNG tank to the receiving pipe, and a depressurizing on-off valve provided in each depressurizing pipe, Each receiving opening / closing valve, each paying opening / closing valve, each BOG is equipped with a connecting pipe for connecting the receiving pipe to the BOG sending pipe and a connecting opening / closing valve provided in the connecting pipe, prior to the cool down.
By selectively opening and closing the on-off valve, return on-off valve, depressurizing on-off valve and connection on-off valve, BOG is extracted from one LNG tank that is the receiving tank, and the extracted BOG is depressurized pipe and receiving piping. Also, it is intended that the receiving pipe is precooled down by flowing it to the BOG sending pipe through the connecting pipe.

According to the configuration of the above invention, in addition to the function of the invention described in claim 3, prior to the cool down, each receiving opening / closing valve, each dispensing opening / closing valve, each BOG opening / closing valve, return opening / closing valve, depressurization opening / closing. By selectively opening and closing the valve and the connecting on-off valve, the BOG from the one LNG tank that becomes the receiving tank
Is extracted, and the extracted BOG is caused to flow to the BOG delivery pipe through the depressurizing pipe, the receiving pipe, and the connecting pipe, so that the receiving pipe is precooled down. Therefore, the receiving pipe is cooled stepwise by the pre-cooldown before the full-scale cooldown. Further, since the BOG is discharged from the receiving tank in advance, the internal pressure of the receiving tank is lowered, and the LN at the time of unloading is decreased.
The differential pressure between the pressure applied by the G truck and the internal pressure increases, and the flow rate of LNG received in the receiving tank increases.

In order to achieve the above object, the invention according to claim 6 is the invention according to claim 5, wherein each receiving opening / closing valve, each paying opening / closing valve, each BOG is provided for precooling down the receiving piping. The purpose of the present invention is to provide a pre-cool down control means for controlling opening / closing of the on-off valve, the return on-off valve, the depressurizing on-off valve and the connection on-off valve.

According to the structure of the above-mentioned invention, in addition to the function of the invention described in claim 5, in order to perform pre-cooldown,
Since the opening and closing of each receiving on-off valve, each dispensing on-off valve, each BOG on-off valve, each return on-off valve, the depressurizing on-off valve and the connection on-off valve is automatically controlled by the pre-cool down control means, each on-off valve described above is manually operated. There is no need to operate.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION The liquefied natural gas of the present invention (L
NG) An embodiment embodying a satellite facility and a method for cooling down a receiving pipe thereof will be described in detail with reference to the drawings.

FIG. 1 shows a circuit configuration of the LNG satellite equipment according to the present embodiment. FIG. 1 shows only relevant parts of the present invention as an LNG satellite facility. LNG
The satellite facility stores LNG at a low temperature, and one pair of the first LNG tank 1 and the second LNG are alternately used as a delivery tank and the other as a receiving tank.
An NG tank 2 and a receiving pipe 3 for receiving LNG supplied from an LNG tank (not shown) into each LNG tank 1, 2 are provided.

At the upstream portion of the receiving pipe 3, three upstream branch pipes 3a, 3b, 3c are provided. Each upstream branch pipe 3a-3c
Each of the LNG receiving arms 4A, 4B, 4C used when unloading LNG from the LNG truck,
Receiving on-off valves 5A, 5B, 5C and check valves 6A, 6B, 6
C and are provided. The downstream portion of the receiving pipe 3 is divided into two downstream branch pipes 3d and 3e and connected to the bottom portions of the LNG tanks 1 and 2. Each of the downstream branch pipes 3d, 3e is provided with a first receiving on-off valve 7A and a second receiving on-off valve 7B for opening and closing the branch pipes 3d, 3e corresponding to the LNG tanks 1, 2. A pipe thermometer 8 corresponding to the temperature detecting means of the present invention for detecting the pipe temperature Tpa is provided in the middle of the receiving pipe 3.

A first delivery pipe 9A for delivering LNG to a vaporizer (not shown) is connected to the bottom of the first LNG tank 1. The first delivery pipe 9A has a first LNG
First for opening and closing the same piping 9A corresponding to the tank 1
A dispensing opening / closing valve 10A is provided. Similarly, a second delivery pipe 9B for delivering LNG to the vaporizer is connected to the bottom of the second LNG tank 2. Second dispensing pipe 9B
A second delivery opening / closing valve 10B corresponding to the second LNG tank 2 is provided to open / close the pipe 9B. Second
The downstream portion of the dispensing pipe 9B is connected to the first dispensing pipe 9A on the downstream side of the first dispensing on-off valve 10A.

The second delivery pipe 9B has a lory pressure pipe 1
The upstream ends of 1 are connected. This pressurizing pipe 11 is LNG
It is for supplying a pressure force by LNG vaporized gas (NG) to the lorry for unloading LNG. A pressure evaporator 12 for pressure-evaporating LNG and a pressure adjusting valve 13 for adjusting the pressure applied by NG are provided in the middle of the pipe 11. Therefore, the LNG delivered from the LNG tanks 1 and 2 to the delivery pipes 9A and 9B, respectively.
Part of the gas flows into the Lori pressurizing pipe 11 and flows into the pressurizing evaporator 12
Is vaporized under pressure to become NG. At this time, the pressure control valve 13 operates to adjust the NG to a predetermined value.
Is applied to the LNG truck.

The Lori pressurizing pipe 11 between the pressurizing evaporator 12 and the pressure adjusting valve 13 has an upstream end of a tank pressurizing pipe 14 for sending out NG for pressurizing the LNG tanks 1 and 2. Connected. The downstream side of the tank pressurizing pipe 14 is branched into two branch pipes 14a and 14b, and each LNG is
A first BOG exhaust pipe 15A and a second BOG exhaust pipe 15A provided to discharge boil-off gas (BOG) at the top of the tanks 1 and 2.
Each of them is connected to the BOG discharge pipe 15B.

The top of the first LNG tank 1 is the first BOG
It is connected to the first BOG delivery pipe 30a via the discharge pipe 15A. The downstream side of the first BOG delivery pipe 30a is B
It is connected to a BOG warmer (not shown) for heating the OG. In the middle of this first BOG delivery pipe 30a, a second
The BOG delivery pipe 30b is connected. The top of the second LNG tank 2 is connected to the first BOG delivery pipe 30a via the second BOG discharge pipe 15B and the second BOG delivery pipe 30b. The BOG discharged from the LNG tanks 1 and 2 is the BOG discharge pipes 15A and 15B and the BOGs.
It is adapted to be delivered to the BOG warmer through delivery pipes 30a and 30b.

Corresponding to the first LNG tank 1, a first NG opening / closing valve 16 is provided in the first branch pipe 14a of the tank pressurizing pipe 14.
A is provided, and the first BOG delivery pipe 30a is connected to the first B
An OG on-off valve 16B is provided. Further, a first pressure gauge 17A as a pressure detecting means for detecting the BOG pressure in the first LNG tank 1 is provided at the connecting portion between the first BOG delivery pipe 30a and the first BOG discharge pipe 15A. Similarly, a second NG opening / closing valve 18A is provided in the second branch pipe 14b of the tank pressurizing pipe 14 corresponding to the second LNG tank 1.
The second BOG on-off valve 18 is connected to the second BOG delivery pipe 30b.
B is provided. In addition, the second BOG delivery pipe 30b and the second
A second portion serving as a pressure detecting unit that detects the BOG pressure in the second LNG tank 2 is provided at the connection portion with the BOG discharge pipe 15B.
A pressure gauge 17B is provided.

The first LNG tank 1 receives the internal pressure of the tank 1 at the time of precooling, which will be described later, in the receiving pipe 3
A first depressurization pipe 19 used to draw out to the downstream side branch pipe 3d is provided. The depressurizing pipe 19 is provided with a first depressurizing on-off valve 20A for opening and closing the same. The first depressurizing pipe 19 and the first depressurizing on-off valve 20A normally have a first LNG flowing through the downstream side branch pipe 3d of the receiving pipe 3.
It is used to receive from the top of the LNG tank 1 and originally functions as a receiving pipe. Similarly, the second LNG tank 2 receives the internal pressure of the second LNG tank 2 at the time of pre-cooling, which will be described later, in the receiving pipe 3
The second depressurization pipe 21 used for extracting to the downstream side branch pipe 3e is provided. The depressurizing pipe 21 is provided with a second depressurizing on-off valve 20B for opening and closing the same. The second depressurizing pipe 21 and the second depressurizing on-off valve 20B normally have a second LNG flowing through the downstream branch pipe 3e of the receiving pipe 3.
It is used to receive from the top of the LNG tank 2 and originally functions as a receiving pipe.

In the Lori pressurizing pipe 11 upstream of the pressurizing evaporator 12, the LNG delivered to the respective dispensing pipes 9A and 9B.
Is connected to the upstream end of a return pipe 22 for returning to the receiving pipe 3. The downstream end of the return pipe 22 is connected to the upstream end of the receiving pipe 3. A return opening / closing valve 23 for opening and closing the return pipe 22 is provided in the middle of the return pipe 22.

The upstream end of the receiving pipe 3 is the first BOG.
A connection pipe 24 is provided to connect to the downstream side of the delivery pipe 30a. A connection opening / closing valve 25 for opening / closing the connecting pipe 24 is provided in the middle of the connecting pipe 24.

In this embodiment, the various on-off valves 5A to
5C, 7A, 7B, 10A, 10B, 16A, 16B,
18A, 18B, 20A, 20B, 23 and 25 are automatic control valves controlled based on a predetermined control signal, and are configured to drive a valve element by an actuator.

In this embodiment, the LNG satellite equipment is provided with a control panel 31 for automatically controlling the operation of the equipment. A controller 32 is provided inside the control panel 31, and a plurality of switches 33 are provided on the front surface of the control panel 31.
An operation panel 34 including, a first lamp 35A and a second lamp 35B are provided. The controller 32 provided on the control panel 31 has an output section at which the various on-off valves 5A to
5C, 7A, 7B, 10A, 10B, 16A, 16B,
18A, 18B, 20A, 20B, 23, 25, and the first and second lamps 35A, 35B are respectively connected. Similarly, the pipe thermometer 8, the first and second BOG pressure gauges 17A and 17B, and the operation panel 34 are connected to the input section of the controller 32, respectively.

In the LNG satellite equipment of this embodiment, when the LNG is unloaded from the LNG truck, the receiving pipe 3 is cooled from the room temperature to the cryogenic temperature suitable for receiving the LNG, and the cooling down is performed. The preceding pre-cooldown process is configured to be executable.
The controller 32 is configured to control both of these processes.

Here, the contents of the pre-cool down processing executed by the controller 32 will be described with reference to the "pre-cool down processing routine" shown in FIG.

This pre-cool down is carried out in the LNG satellite equipment prior to the LNG unloading from the LNG loli, and is before the cool down described later, and pre-cools the LNG receiving pipe 3 before the arrival of the LNG loli. It is a process of down. This pre-cool down
It also serves as depressurizing work for lowering the internal pressure of the LNG tanks 1 and 2 used as receiving tanks.

First, at step 100, when a predetermined switch 33 on the operation panel 34 of the operation panel 31 is turned on, at step 110, the controller 32 opens a predetermined open / close valve to start precooling. Control.

For example, when the first LNG tank 1 is a receiving tank for receiving LNG, the controller 3
2 opens the first depressurizing on-off valve 20A and the connection on-off valve 25. In addition, the controller 32 includes a first receiving opening / closing valve 7A, a first payout opening / closing valve 10A, a first NG opening / closing valve 16A,
The first BOG on-off valve 16B and the return on-off valve 23 are closed. Similarly, when the second LNG tank 2 is a receiving tank that receives LNG, the controller 32 opens the second depressurizing on-off valve 20B and the connection on-off valve 25, and the second receiving on-off valve 7B and the second payout. Open / close valve 10B, second NG open / close valve 18A, second BOG open / close valve 18B, and return open / close valve 2
3 is closed.

Next, in step 120, the controller 3
In No. 2, the first lamp 35A is turned on to indicate that the pre-cool down is in progress.

Next, in step 130, the controller 3
2 reads the BOG pressure Pbog. That is, when the first LNG tank 1 is used as the receiving tank as described above, the controller 32 reads the detection value of the first pressure gauge 17A as the value of the BOG pressure Pbog.

Next, in step 140, the controller 3
2 is the read BOG pressure Pbog is a predetermined set value P1
It is determined whether or not Here, for example, "0.3 MPa" can be applied as the set value P1.

If the above determination result is negative, the controller 32 returns the process to step 130 and returns to step 13
The processing of 0 and 140 is repeated. These steps 130,
While the process of 140 is repeated, as shown by the thick line in FIG. 3, BOG at a cryogenic temperature (about −130 ° C.) is extracted from the top of the first LNG tank 1 to the first depressurization pipe 19, and the B
The OG is flowed through the downstream branch pipe 3d, the receiving pipe 3 and the connecting pipe 24 to the first BOG sending pipe 30a, and the receiving pipe 3 is precooled down. On the other hand, if the determination result is affirmative, the controller 32 moves the process to step 150 to end the precooldown.

In step 150, the controller 32
Controls to close the predetermined on-off valve that was opened in step 110 above.

Then, in step 160, the controller 32 turns off the first lamp 35A to indicate that the pre-cooldown is finished, and the process is finished.

That is, in this "pre-cooldown processing routine", BOG is extracted from one of the LNG tanks 1 and 2 which are receiving tanks before the cooldown, and the extracted BOG is received in the depressurizing pipes 19 and 21. The receiving pipe 3 is precooled down by flowing it to the first BOG delivery pipe 30a through the pipe 3 and the connecting pipe 24. That is, prior to the cool down, each of the receiving opening / closing valves 7A, 7B, each of the dispensing opening / closing valves 10A, 10B, each of the NG opening / closing valves 16A, 18A, each of the BOG opening / closing valves 16B, 18B, the return opening / closing valve 23, the depressurizing opening / closing valve 20A, 20B and the connection on-off valve 25 are selectively opened and closed. Then, the BOG is extracted from one of the LNG tanks 1 and 2 which will be the receiving tank,
The extracted BOG is passed through the depressurizing pipes 19 and 21, the receiving pipe 3, the connecting pipe 24 and the like to form the first BOG sending pipe 30a.
The receiving pipe 3 is pre-cooled down by flowing it to. Due to this pre-cooldown, the receiving pipe 3 in the normal temperature state will have a temperature of "-80 to-" within about 1 hour.
It is cooled down to about 100 ° C. The controller 32 that executes the "precooldown processing routine" corresponds to the precooldown control means of the present invention.

Next, the contents of the cooldown process executed by the controller 32 will be described with reference to the "cooldown process routine" shown in FIG.

This cool down is carried out in the LNG satellite equipment prior to the LNG unloading from the LNG loli, and is a process carried out to cool down the LNG receiving pipe 3 before the arrival of the LNG loli. This processing is performed by itself or in combination with the above-described pre-cooldown processing.

First, at step 200, when a predetermined switch 33 on the operation panel 34 of the operation panel 31 is turned on, at step 210, the controller 32 opens a predetermined open / close valve to start cool down. Control.

For example, when the first LNG tank 1 is a receiving tank for receiving LNG, the controller 3
2 opens the 1st receiving opening / closing valve 7A, the 2nd delivery opening / closing valve 10B, and the return opening / closing valve 23. In addition, controller 3
2 is a first payout opening / closing valve 10A, a first NG opening / closing valve 16A,
The first depressurizing on-off valve 20A and the connection on-off valve 25 are closed. Similarly, when the second LNG tank 2 is a receiving tank that receives LNG, the controller 32 opens the second receiving on-off valve 7B, the first payout on-off valve 10A, and the return on-off valve 23. In addition, the controller 32 closes the second payout opening / closing valve 10B, the second NG opening / closing valve 18A, the second depressurizing opening / closing valve 20B, and the connection opening / closing valve 25.

Next, in step 220, the controller 3
2 is the second to show that it is in cooldown
The lamp 35B is turned on.

Next, in step 230, the controller 3
2 reads the pipe temperature Tpa. That is, when the first LNG tank 1 is used as the receiving tank as described above, the controller 32 reads the value detected by the pipe thermometer 8 as the value of the pipe temperature Tpa.

Next, in step 240, the controller 3
In step 2, it is determined whether the read pipe temperature Tpa is equal to or lower than a predetermined set value T1. Here, as the set value T1,
For example, "-120 ° C" can be applied.

When the above determination result is negative, the controller 32 returns the processing to step 230 and returns to step 23.
The process of 0,240 is repeated. These steps 230,
While the process of 240 is repeated, as shown by the thick line in FIG. 5, from the bottom of the second LNG tank 2 to the second delivery pipe 9B.
Very low temperature (about −140 ° C.) LNG is discharged, and the LNG is flown to the first LNG tank 1 via the Lori pressurizing pipe 11, the return pipe 22, the receiving pipe 3 and the downstream branch pipe 3d, and the receiving pipe 3 Cooldown is done. On the other hand, if the determination result is affirmative, the controller 32 moves the process to step 250 to end the cooldown.

In step 250, the controller 32
Controls to close the predetermined on-off valve which was controlled to be opened in step 210.

Then, in step 260, the controller 32 makes a second indication to indicate that the cooldown is complete.
The lamp 35B is turned off, and the process ends.

That is, this "cooldown processing routine"
Then, within a predetermined time immediately before the arrival of the LNG loli, the LNG is discharged from one of the LNG tanks 1 and 2 serving as a discharge tank to the discharge pipes 9A and 9B, and the discharged LNG is discharged.
Is supplied to the other LNG tank 2 or 1 serving as a receiving tank through the return pipe 22 and the receiving pipe 3 to cool the receiving pipe 3 in advance. That is, the controller 32 starts the cooling down of the receiving pipe 3 by receiving the receiving opening / closing valves 7A, 7B, the dispensing opening / closing valves 10A, 10B, the NG opening / closing valves 16A, 18A, and the B's.
OG on-off valves 16B, 18B, depressurizing on-off valves 20A, 20
B, after controlling the opening / closing of the return opening / closing valve 23 and the connection opening / closing valve 25, when the detected pipe temperature Tpa reaches a predetermined set value T1, the opening / closing valves 7A, 7B, 10A, 10B, 16A, 16B, 18
The opening / closing of A, 18B, 20A, 20B, 23, 25 is controlled. By this cooldown, the receiving pipe 3 in the normal temperature state is cooled to about "-120 ° C". The controller 32 that executes the "cooldown processing routine" corresponds to the cooldown control means of the present invention.

As described above, the LNG of the present embodiment
In the satellite equipment, the LNG is dispensed by using one of the LNG tanks 1 and 2 as a dispensing tank from the state where both the pair of LNG tanks 1 and 2 are full.
When the G tank becomes almost empty, its LNG tank 1,
Waiting for LNG to be received from the LNG tanker 2 using the LNG tank 2 as the receiving tank, this time the other LNG tanks 2, 1 will be used as the dispensing tank.

Here, according to the above-described cooling method for the receiving pipe of the LNG satellite facility, one LN serving as a payout tank is delivered within a predetermined time immediately before the arrival of the LNG truck.
LNG is discharged from the G tanks 1 and 2 to the discharge pipes 9A and 9B. Then, the delivered LNG is flown through the return pipe 22 and the receiving pipe 3 to the other LNG tanks 2 and 1 serving as receiving tanks. As a result, the receiving pipe 3 is cooled down in advance before receiving the LNG from the LNG truck.

Therefore, since the cool down of the receiving pipe 3 is completed before the unloading of the LNG by the LNG lorry is started, the unloading time of the LNG is not prolonged due to the cool down. Further, since the cool down is performed only for the predetermined time immediately before the arrival of the LNG loli, the heating time of the LNG flowing through the return pipe 22 and the receiving pipe 3 is shortened, the generation of BOG is suppressed, and the tank for receiving is reduced. BOG is prevented from flowing into the LNG tanks 1 and 2. Therefore, in an LNG satellite facility that uses one of the pair of LNG tanks 1 and 2 as a delivery tank and the other as a receiving tank, it is possible to shorten the LNG unloading time and improve the efficiency of the unloading work. You will be able to plan.

According to the cooling down method of the receiving pipe of this embodiment, prior to the cooling down of the receiving pipe 3, one of the LNG tanks 1 and 2 serving as the receiving tank is connected to the BOG.
Is extracted. Then, the extracted BOG passes through the depressurizing pipes 19 and 21, the receiving pipe 3 and the connecting pipe 24 to B.
It is flowed to the OG delivery pipe 30a. As a result, the receiving pipe 3 is precooled down.

Therefore, the receiving pipe 3 is cooled stepwise by the pre-cooldown before the cooldown. Therefore, in some cases, it is possible to prevent the receiving pipe 3 from suddenly receiving cold heat and contracting and deforming. In addition, since the BOG is discharged in advance from the LNG tanks 1 and 2 that are the receiving tanks, the internal pressure on the receiving tank side is reduced, and the pressure and internal pressure of the LNG lorry during unloading are reduced. The differential pressure between the two increases and becomes the receiving tank L
The flow rate of LNG received in the NG tanks 1 and 2 is increased. From this point of view, the LNG unloading time from the LNG lorry can be further shortened, and the efficiency of the unloading work can be further improved.

In the LNG satellite equipment of this embodiment, in order to start and end the cooldown, each of the receiving opening / closing valves 7A and 7B, each of the dispensing opening / closing valves 10A and 10B, each of the NG opening / closing valves 16A and 18A, and each of the BOG opening / closing. The controller 32 automatically controls the opening and closing of the valves 16B and 18B, the depressurizing on-off valves 20A and 20b, the return on-off valve 23, and the connection on-off valve 25. Therefore, each of the on-off valves 7A, 7B, 1 is manually operated.
0A, 10B, 16A, 16B, 18A, 18B, 20
There is no need to operate A, 20B, 23, 25. Therefore, it is possible to reduce the burden of the driving work that the operator has to perform for the cool down.

Similarly, in the LNG satellite equipment of this embodiment, in order to perform pre-cool down, each receiving on-off valve 7A, 7B, each paying on-off valve 10A, 10B, each NG.
Open / close valves 16A, 18A, BOG open / close valves 16B, 18
The controller 32 automatically controls opening / closing of B, the return opening / closing valve 23, the depressurizing opening / closing valves 20A and 20B, and the connection opening / closing valve 25. Therefore, each on-off valve 7A, 7B,
10A, 10B, 16A, 16B, 18A, 18B, 2
There is no need to operate 3, 20A, 20B, 25. Therefore, it is possible to reduce the burden of the driving work that the operator has to perform for the pre-cooldown.

The present invention is not limited to the above-mentioned embodiment, but can be carried out as follows within the scope of the invention.

(1) In the above embodiment, the case where the pre-cooldown processing and the cooldown processing are combined has been described. However, the precooldown processing is omitted and only the cooldown processing is performed. It can also be converted.

(2) In the above embodiment, each on-off valve 7
A, 7B, 10A, 10B, 16A, 16B, 18A,
18B, 23, 20A, 20B, and 25 are used as automatic control valves, and they are controlled by the controller 32. On the other hand, each on-off valve 7A, 7B, 10A, 10
B, 16A, 16B, 18A, 18B, 23, 20A,
All or part of 20B and 25 may be manually operated valves that are manually operated individually.

(3) In the above embodiment, the present invention is embodied in the LNG satellite equipment having the circuit configuration shown in FIG. 1. However, the circuit configuration shown in FIG. The present invention can also be embodied in a properly modified part.

[0068]

According to the configuration of the invention described in claim 1,
In an LNG satellite facility that uses one of a pair of LNG tanks as a delivery tank and the other as a receiving tank, the unloading time can be shortened because the cool down is performed immediately before the arrival of the LNG loli. There is an effect that the work efficiency can be improved.

According to the configuration of the invention described in claim 2, in addition to the effect of the invention described in claim 1, precooling is performed, so that in some cases, the receiving pipe suddenly receives cold heat and shrinks and deforms. Can be prevented.
Further, since the BOG is paid out in advance by the pre-cool down, the LNG unloading time from the LNG lorry can be further shortened, and the efficiency of the unloading work can be further improved.

According to the third aspect of the present invention, in the LNG satellite equipment using one of the pair of LNG tanks as the payout tank and the other as the receiving tank, the cooldown is performed immediately before the arrival of the LNG loli. Since it is performed, there is an effect that the unloading time can be shortened and the efficiency of the unloading work can be achieved.

According to the configuration of the invention described in claim 4, in addition to the effect of the invention described in claim 3, since it is not necessary to manually operate each on-off valve, it is necessary for the operator to perform the cool-down. There is an effect that the burden of driving work can be reduced.

According to the configuration of the invention described in claim 5, in addition to the effect of the invention described in claim 3, pre-cool down is performed, so in some cases, the receiving pipe suddenly receives cold heat and shrinks and deforms. Can be prevented.
Further, since the BOG is paid out in advance by the pre-cool down, the LNG unloading time from the LNG lorry can be further shortened, and the efficiency of the unloading work can be further improved.

According to the structure of the invention described in claim 6, in addition to the effect of the invention described in claim 5, since it is not necessary to manually operate each on-off valve, an operator should perform it for precooling. There is an effect that the burden of driving work can be reduced.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram showing an LNG satellite facility according to an embodiment.

FIG. 2 is a flowchart showing a “pre-cooldown processing routine”.

FIG. 3 is an explanatory diagram showing a flow of BOG at the time of precooling.

FIG. 4 is a flowchart showing a “cooldown processing routine”.

FIG. 5 is an explanatory diagram showing a flow of LNG at the time of cool down.

FIG. 6 is a circuit diagram showing a conventional piping facility.

[Explanation of symbols]

1 1st LNG tank 2 2nd LNG tank 3 receiving piping 3d downstream branch pipe 3e downstream branch pipe 7A 1st receiving opening / closing valve 7B 2nd receiving opening / closing valve 8 piping thermometer (temperature detection means) 9A 1st delivery piping 9B 2nd delivery piping 10A 1st 1 delivery opening / closing valve 10B 2nd delivery opening / closing valve 15A 1st BOG discharge pipe 15B 2nd BOG discharge pipe 16B 1st BOG opening / closing valve 18B 2nd BOG opening / closing valve 19 1st depressurizing pipe 20A 1st depressurizing opening / closing valve 20B 2nd depressurizing opening / closing valve 21 Second depressurization pipe 22 Return pipe 23 Return on-off valve 24 Connection pipe 25 Connection on-off valve 30a First BOG delivery pipe 30b Second BOG delivery pipe 32 Controller (cool-down control means, pre-cool-down control means)

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shoube Masahiro             186 Nishitsuka-cho, Hamamatsu City, Shizuoka Prefecture Chubu Gas Co., Ltd.             Inside the Hamamatsu Factory (72) Inventor Kazuo Ito             Toho Gas, 19-18 Sakurada-cho, Atsuta-ku, Nagoya-shi             Engineering Co., Ltd. F-term (reference) 3E073 AA01 DA02 DB04 DD03

Claims (6)

[Claims] 1. A pair of LNG tanks in which LNG is stored at a low temperature and one of which is alternately used as a delivery tank and the other of which is used as a receiving tank, and LNG supplied from an LNG tanker is received in each of the LNG tanks. A receiving pipe for discharging the LNG from the LNG tanks to the vaporizer, and a return pipe for returning the LNG discharged to the respective discharging pipes to the receiving pipes. A method for cooling down a receiving pipe of an LNG satellite facility, wherein LNG is discharged from one of the LNG tanks serving as the discharging tank to the discharging pipe within a predetermined time immediately before the arrival of the LNG loli. Delivery of LNG through the return pipe and the receiving pipe to the other LNG tank serving as the receiving tank LN, which is characterized in that so as to cool down in advance
How to cool down the receiving piping of G satellite equipment. 2. The LNG satellite equipment is a BOG for sending BOG from each of the LNG tanks.
A delivery pipe, a connection pipe that connects the reception pipe to the BOG delivery pipe, and a depressurization pipe for releasing the internal pressure of each LNG tank to the reception pipe, prior to the cooldown,
From the one LNG tank serving as the receiving tank to the B
The pre-cool down of the receiving pipe is performed by extracting the OG and flowing the extracted BOG to the BOG sending pipe through the depressurizing pipe, the receiving pipe and the connecting pipe. LN described
How to cool down the receiving piping of G satellite equipment. 3. A pair of LNG tanks that store LNG at a low temperature and one of which is alternately used as a payout tank and the other as a receiving tank, and receive LNG supplied from LNG lory to each of the LNG tanks. A receiving pipe for making the LNG tank, a receiving opening / closing valve provided in the receiving pipe corresponding to the LNG tank, a paying pipe for paying out LNG from the LNG tank to the carburetor, and the LNG. A payout on-off valve provided in each of the payout pipes corresponding to the tank, a return pipe for returning LNG paid out to each of the payout pipes to the receiving pipe, and a return on-off valve provided in the return pipe And L
Before the arrival of the NG loli, the LNG tank is dispensed from one LNG tank serving as the dispensing tank by selectively opening and closing the receiving on-off valves, the dispensing on-off valves, and the return on-off valve, and paying them. The LNG satellite facility is configured to cool down the receiving pipe by flowing a required amount of the discharged LNG to the other LNG tank serving as the receiving tank through the return pipe and the receiving pipe. 4. Each of the receiving on-off valves, each of the dispensing on-off valves and the return on-off valve is a control valve controlled based on a predetermined control signal, and the pipe temperature of the receiving pipe is detected. After detecting the temperature detecting means and controlling the opening and closing of each of the receiving opening / closing valves, the respective paying opening / closing valves and the return opening / closing valve in order to start the cooling down of the receiving piping, the detected piping temperature becomes a predetermined value. A cooldown control means for controlling the opening and closing of each of the reception opening / closing valves, the respective payout opening / closing valves and the return opening / closing valve in order to end the cooldown when reached. LNG satellite equipment described in 3. 5. A BOG delivery pipe for delivering BOG from each of the LNG tanks, a BOG on-off valve provided in each of the BOG delivery pipes corresponding to each of the LNG tanks, and an internal pressure of each of the LNG tanks. A depressurizing pipe for pulling out to the receiving pipe, a depressurizing on-off valve provided on each depressurizing pipe, a connecting pipe connecting the receiving pipe to the BOG delivery pipe, and a connecting on-off valve provided on the connecting pipe. And selectively opening and closing each of the receiving on-off valves, each of the dispensing on-off valves, each of the BOG on-off valves, the return on-off valve, the depressurizing on-off valve and the connection on-off valve prior to the cool-down. The BOG is extracted from one of the LNG tanks serving as the receiving tank, and the extracted BOG is passed through the depressurizing pipe, the receiving pipe, and the connecting pipe to the BOG.
The LNG satellite equipment according to claim 3, wherein the receiving pipe is pre-cooled down by flowing it to a sending pipe. 6. The receiving opening / closing valves, the dispensing opening / closing valves, and the B's for precooling down the receiving piping.
The LN according to claim 5, further comprising a pre-cool down control means for controlling opening / closing of an OG on-off valve, the return on-off valve, the depressurizing on-off valve and the connection on-off valve.
G satellite equipment.