JP2002356231A - Delivery method and delivery system for liquefied natural gas - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a delivery method and delivery system for liquefied natural gas inexpensively transporting a large quantity of LNG. SOLUTION: In the delivery method for the liquefied natural gas, a schedule 23 for secondary delivery is prepared and a pressure in delivery by a secondary delivery means 14 is managed by using the delivery system 10 for the LNG having a primary delivery means 12 delivering the LNG to a primary base 11, the secondary delivery means 14 delivering the LNG to a secondary base 13, a calculating means 16 predicting changes in fluctuation factors including an LNG pressure and/or an LNG pressure of a transportation tank 15 of the secondary delivery means 14, an inventory managing means 18 for grasping an inventory amount of the LNG inside a storage tank 17, a shipping predicting means 20, and a schedule preparing means 21 preparing the schedule 23 of the secondary delivery means 14 in consideration of these.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and a system for delivering liquefied natural gas to a consumer via a delivery means and a receiving terminal.

[0002]

2. Description of the Related Art Natural gas, which is clean energy and has an important position as a fuel for power generation and as a raw material for city gas, depends largely on imports from abroad in Japan. Gas (LNG;
L as Liquidified naturals)
They were transported by sea to Japan by NG ships, received at receiving bases, vaporized and used. LNG
For the distribution of natural gas, a receiving base should be installed as close as possible to thermal power plants and city gas companies as consumers, and natural gas vaporized from this receiving base should be delivered through pipes, or relatively small such as tank trucks. A method has been adopted in which a supply is made to a customer by means of conveying the capacity.

[0003]

However, the above-mentioned conventional liquefied natural gas delivery system is excellent in supplying LNG in a timely manner according to the demands of customers, but LNG is supplied at -160 ° C. Transporting large amounts of LNG over long distances is limited by liquefaction at low temperatures. For this reason, LNG consumers, especially large-scale customers, have a locational restriction that they must be located relatively close to a limited number of LNG receiving bases. It was a factor that hindered. The present invention has been made in view of such circumstances, and an object of the present invention is to provide a liquefied natural gas delivery method and a delivery system for transporting a large amount of LNG at low cost.

[0004]

According to the present invention, there is provided a method for delivering liquefied natural gas according to the present invention, wherein the liquefied natural gas is delivered to a primary base by a primary delivery means, and then to a secondary base by a secondary delivery means. In the method for delivering liquefied natural gas to the secondary delivery means and further to the consumer, the schedule of the secondary delivery means may include a variation including an LNG pressure and / or a LNG temperature of a transport tank provided in the secondary delivery means. Factors, the inventory amount of liquefied natural gas in the storage tank of the secondary base, and the predicted amount of liquefied natural gas sent out from the secondary base to the customer. To control the pressure during delivery. The primary base is, for example, constructed in a large port and has a storage tank on which large vessels can be anchored and which can store the liquefied natural gas by adjusting its pressure and temperature. The primary delivery means refers to delivery means to the primary base, for example, a large-scale LN of 30,000 to 50,000 ton class
Vessels G, so-called oceangoing vessels, fall under this category.

[0005] The secondary base is, for example, constructed in a port capable of berthing domestic vessels, and can be formed smaller than the primary base. The secondary delivery means refers to a means for transporting LNG from a primary base to a secondary base.
Ships of the order of up to 5,000 tons, so-called coastal ships, fall under this category. Between the secondary terminal and the customer, for example,
NG can be transported in a vaporized state, and can also be supplied to consumers using a transportation means such as a tank truck. The vaporization temperature (boiling point) of liquefied natural gas is
Since the temperature is low at about −160 ° C., when the liquefied natural gas is transported by a coastal ship or the like, the liquefied natural gas gradually evaporates in the transport tank, and the pressure in the transport tank increases. If left untreated, natural gas must be released to the atmosphere to protect the transport tanks.
Taking into account the stock of liquefied natural gas in the storage tank provided at the secondary terminal, in addition to supplementing the predicted amount of LNG sent out from the secondary terminal to the customer, the LNG pressure of the transport tank, and And / or LNG temperature needs to be taken into account.

Here, the LNG pressure and / or
Alternatively, the reason why the LNG temperature is included is that in order to maintain the pressure in the transport tank below a predetermined value, it is necessary to grasp at least one of the pressure and the temperature, preferably both. Also, the reason why the predicted delivery amount is taken into account is that the amount is directly related to the replenishment amount of LNG to the transport tank. With such a configuration, a schedule is created in consideration of the LNG pressure and / LNG temperature of liquefied natural gas which is difficult to handle, pressure is reliably controlled, and a large amount of LNG is generated.
Can be transported at low cost.

Here, when the schedule of the secondary delivery means is created, it is possible to consider the LNG filling rate of the transport tank. For example, when liquefied natural gas is stored in a transport tank in a substantially full state, the liquefied natural gas evaporates gradually with the passage of days, and the temperature inside the transport tank gradually increases. On the other hand, in a state where the inside of the transport tank is almost empty, LNG evaporates in the transport tank and is in a gaseous state. In the case of gas, the pressure and temperature rapidly rise in the early stages in response to a change in external temperature, but reach the limit soon, and the fluctuations in pressure and temperature become smaller as the number of days elapses. Therefore, by adding the LNG filling rate to the fluctuation factors, changes in pressure and temperature rise can be predicted accurately, and a schedule can be created with high accuracy.

[0008] Further, when the liquefied natural gas is transferred from the secondary delivery means to the secondary base, the flash gas generated at the secondary base is recovered and transported to the primary base by the secondary delivery means. Thus, the flash gas can be processed at the primary station. The flash gas is L
This refers to the vaporized natural gas generated when NG is transferred. When the liquefied natural gas flows from the transport tank to the storage tank, a difference in temperature and pressure between the transport tank and the storage tank generates a flash gas in which a part of the liquefied natural gas evaporates. If the generated flash gas is left unattended, the pressure in the storage tank at the secondary terminal increases, and may exceed the allowable range. In this case, it is necessary to remove the flash gas and perform the combustion process. At this time, natural gas has a large amount of energy,
Depending on the equipment at the secondary base, there were cases where the processing could not be completed, but since the flash gas is collected by the secondary delivery means and processed at the primary base, the processing can be performed reliably. In addition, since the flash gas can be used for other operations at the primary base, the operation can be performed efficiently by preventing waste of raw materials.

Further, it is possible to set the pressure in the transport tank during delivery to a predetermined value or less. Liquefied natural gas evaporates gradually in an atmosphere of -160 ° C or higher, and increases the pressure in the transport tank. If this is left unchecked, the pressure in the transport tank will rise and the natural gas may need to be released to the atmosphere to protect the tank. Schedules can be created. Pressure transport tank, it is necessary to maintain the range of 0.5 to 10 / cm ^2, when the pressure is less than 0.5 kg / cm ^2,
Flash gas during loading increases. On the other hand, if the pressure is 1
If it exceeds 0 kg / cm ² , the cost of manufacturing a transport tank and heat insulating processing increases. Therefore, when the pressure of the transport tank is set to 1.0 to 3.0 kg / cm ² , more preferable results are obtained. As a method of suppressing the pressure rise in the transport tank, for example, the time of daytime transport is changed to the time of nighttime transport, or a temporary depot located near the primary base during transport is temporarily degassed. it can. With such a configuration, LNG can be transported to a long distance. Further, the secondary delivery means can be a coastal ship. Since LNG is transported by coastal vessels, it can be transported in large quantities.

A liquefied natural gas delivery system according to the present invention, which meets the above object, comprises a primary delivery means for delivering liquefied natural gas to a primary base, and a secondary delivery means for delivering the liquefied natural gas from the primary base to a secondary base. Delivery means, and LNG pressure and / or LN of a transport tank provided in the secondary delivery means
G calculating means for predicting changes in fluctuation factors including temperature, inventory management means for grasping the amount of liquefied natural gas in the storage tank of the secondary base, and liquefied natural gas from the secondary base to consumers. Shipping forecasting means for estimating the predicted gas delivery amount, and a change in the fluctuation factor predicted by the calculating means,
A schedule creation unit that creates a schedule for the secondary delivery unit in consideration of the liquefied natural gas inventory amount grasped by the inventory management unit and the estimated delivery amount estimated by the shipment prediction unit. The schedule creator calculates the required transport amount from the estimated predicted delivery amount and the liquefied natural gas inventory amount, and calculates the expected increase pressure in the transport tank of the secondary delivery device.
With this configuration, it is possible to reliably perform pressure management during transportation, and to prevent an accident such as the natural gas in the tank from being released to the atmosphere due to a rise in pressure.

Here, it is also possible to make the calculating means predict a change in a variation factor in consideration of an LNG filling rate of the transport tank provided in the secondary delivery means. Since the ratio of the pressure change in the transport tank to the temperature change in the external environment differs depending on the LNG filling rate, the expected rising pressure of the transport tank is improved by taking into account the LNG filling rate and creating a schedule based on this. It can be calculated accurately. Further, in the secondary delivery means,
It is also possible to provide a gas recovery means for recovering the flash gas generated at the secondary terminal, and to provide a processing means for processing the recovered flash gas at the primary terminal. The gas recovery means can be configured using a transport tank. When the flash gas cannot be processed at the secondary terminal, or when the flash gas can be used for other purposes at the primary terminal, the flash gas generated in the gas recovery means of the secondary delivery means is filled with the generated flash gas, and the gas is transferred to the primary terminal. Can be transported. The processing means of the primary terminal can take out, for example, the amount of heat generated by burning the flash gas. With this configuration, the generated flash gas can be effectively used.

Further, the secondary delivery means may be provided with a vaporization amount control means for setting the vaporization amount of the liquefied natural gas being delivered to a predetermined value or less. The vaporization amount control means includes, for example, a pressure gauge capable of measuring the pressure in the transport tank and an exhaust valve capable of discharging the vaporized natural gas to the outside. The amount of liquefied natural gas vaporized during delivery is 0.7%
When the amount of vaporization exceeds 0.7%,
The pressure in the transport tank increases and the frequency of release of natural gas due to the operation of the safety valve increases, resulting in loss of natural gas,
Moreover, it is not preferable from an environmental point of view. If the amount of vaporization is expected to exceed a specified value, it is possible to call at a nearby primary base, open the exhaust valve, collect the vaporized natural gas in the transport tank, and reduce the pressure It is. With this configuration, the transport tank can be prevented from being damaged, and transport can be stably performed. Further, the secondary delivery means can be a coastal ship. With this configuration, a large amount of liquefied natural gas can be carried at once, and the transportation efficiency can be improved.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the accompanying drawings to provide an understanding of the present invention. As shown in FIGS. 1 and 2, a liquefied natural gas delivery system 10 according to one embodiment of the present invention
Is an ocean-going vessel 12 which is an example of a primary delivery means for delivering liquefied natural gas (hereinafter referred to as LNG) to a primary base 11.
And a coastal ship 14 which is an example of secondary delivery means for delivering LNG from the primary base 11 to the secondary base 13.
Further, the delivery system 10 includes a calculating unit 16 for predicting a change in a variation factor including the LNG pressure and the LNG temperature of the transport tank 15 provided on the coastal ship 14, and the LNG in the storage tank 17 of the secondary base 13. Inventory management means 18 for ascertaining the inventory amount of the cargo, shipping forecasting means 20 for estimating the estimated amount of LNG to be sent from the secondary base 13 to the customers 19 such as chemical manufacturers and gas supply companies, and secondary delivery means (including Vessel 1
4) a schedule creating means 21 for creating the schedule 23. The details will be described below.

First, referring to FIG.
LNG delivery route will be described. Oceangoing vessels 12
Is a large vessel of, for example, 30,000 to 50,000 tons, carries LNG into a primary base 11 provided in large-scale ports located at several places in Japan, and large-sized tanks capable of adjusting the temperature and pressure of the carried LNG. Store at 22. The coastal ship 14 is, for example, a ship of 3 to 5,000 tons, receives a predetermined amount of LNG in a liquid state from the large tank 22 to the transport tank 15,
The LNG is delivered to the secondary bases 13 provided in a large number of small and medium-sized ports, respectively, and the LNG flows into the storage tanks 17 provided in the respective secondary bases 13. The LNG in the storage tank 17 is transported to the customer 19 directly or via a satellite (relay station) by a truck, a tank lorry, or a pipeline. Since LNG has a lower boiling point than LPG (liquefied petroleum gas), it must be managed with care to prevent the temperature and pressure during transportation from increasing. Here, the LNG temperature and the LNG pressure are LNG
Refers to the temperature and pressure in the transport tank 15 in which

Next, referring to FIG.
The inventory management unit 18, the shipment prediction unit 20, and the schedule creation unit 21 will be described. Each of these means
Built in one or more computers as a program, the location of the computer can be wired or wirelessly exchanged data between the primary base 11, secondary base 13, oceangoing vessel 12, and coastal vessel 14 Position is not particularly limited. First, referring to FIGS.
The calculation means 16 will be described. The calculating means 16 inputs the outside air temperature, the seawater temperature, the initial tank temperature, the initial pressure, the residual liquid amount, etc., based on the shape of the transport tank 15, the voyage conditions of the coastal ship 14, and the like. And pressure changes can be simulated. The remaining liquid amount refers to the amount of LNG stored in the transport tank 15, and the LNG filling rate can be calculated from this amount.
That is, the LNG temperature and the LNG
Changes in NG pressure can be predicted. FIG. 3 shows a graph that predicts a change in LNG temperature and a change in LNG pressure when LNG is fully loaded in the transport tank 15. As shown in FIG. 3, 20
When the day has elapsed, the temperature in the transport tank 15 is reduced by -14.
It can be expected that the temperature will reach 4 ° C. and the pressure will reach 2.3 kg / cm ² G. Also, as shown in FIG. 4, when the loading state in the transport tank 15 is substantially empty, the rate of increase in temperature and pressure immediately after departure is large because the gas expands. It can be predicted that the rate of increase gradually decreases, and after 20 days, the temperature becomes substantially constant at about 40 ° C., and the LNG pressure does not reach 2.5 kg / cm ² G.

Next, referring to FIG.
Will be described. The inventory management means 18 grasps the amount of LNG in the storage tank 17 and the amount of incoming and outgoing shipments,
It is provided so that data can be exchanged with the schedule creation means 21. Next, the shipment prediction means 20 will be described. The shipment forecasting means 20 can receive order data from the customer 19 from a management computer (not shown), and has a past order database.
It is possible to estimate the predicted delivery amount for each month and week.
In addition, the shipment prediction means 20
It is provided so that data can be transferred between and.

Next, the schedule creating means 21 will be described with reference to FIGS. The schedule creation means 21 takes into account the change in the fluctuation factors predicted by the calculation means 16, the liquefied natural gas inventory amount grasped by the inventory management means 18, and the estimated delivery amount estimated by the shipment prediction means 20. The schedule 23 of the secondary delivery means by the ship 14 is created. For example, it is possible to deliver only the amount obtained by subtracting the stock amount from the predicted delivery amount, or to deliver an amount equal to the predicted delivery amount so that the storage tank 17 is always full. As shown in FIG. 5, for example, a predetermined coastal ship 14 is fully loaded, the time taken from the primary base 11 to the secondary base 13 is calculated, and the departure time and the arrival time are determined. It is preferable that the operating time be utilized at night as much as possible in order to suppress a rise in temperature. Further, a predicted amount of change in LNG pressure and LNG temperature is calculated. At night, the temperature of the outside air drops,
The rate of increase in LNG pressure and LNG temperature decreases. On the second day of schedule 23, coastal vessel 14 transfers LNG from transport tank 15 to storage tank 17,
Move to the primary base 11 again. At this time, since the coastal ship 14 is empty, the rate of increase in the LNG temperature and the LNG pressure in the transport tank 15 is high.

Here, the gas recovery means 24 provided on the coastal ship 14 and the processing means 25 provided on the primary base 11 will be described. The gas recovery means 24 is provided in the transport tank 15 of the coastal ship 14 and removes LNG from the transport tank 15.
The flash gas generated at the time of transfer to the storage tank 17 of the secondary base 13 can be recovered. The amount of the generated flash gas varies depending on the temperature difference and the pressure difference between the transport tank 15 and the storage tank 17, and when the generated amount is small, the flash gas can be stored in the storage tank 17 as it is. However, when a large amount of flash gas is generated, the pressure in the storage tank 17 increases,
Since the storage tank 17 may be damaged, it is necessary to release generated flash gas to the outside of the storage tank 17 and perform a combustion process or the like. Here, when the processing facility is not provided in the secondary base 13 or when the amount of generated flash gas exceeds the processing limit of the processing facility, the generated flash The gas can be collected in the transport tank 15 after the transfer of the LNG. With this configuration, the burden on the secondary base 13 can be reduced. In the schedule 23 shown in FIG. 5, a schedule when the gas recovery means 24 is not used is used. Each primary station 11 is provided with a processing means 25 capable of burning flash gas. The coastal ship 14 that has recovered the flash gas at the secondary base 13 can call at the nearby primary base 11 and process the flash gas in the transport tank 15. In addition, the coastal ship 14 that does not collect the flash gas can process the natural gas vaporized in the transport tank 15 at the primary base 11 that performs the next delivery. With this configuration, the pressure in the transport tank 15 can be reduced, and subsequent operations can be performed stably.

Further, the coasting ship 14 has a vaporization amount control means 2 for setting the vaporization amount of the liquefied natural gas being delivered to a predetermined value or less.
6 are provided. The vaporization amount control means 26 has a pressure gauge (not shown) that measures the pressure in the transport tank 15, an alarm device that generates an alarm when a set pressure is detected, and an exhaust valve. If the LNG pressure rises more than expected during transportation of the LNG, for example because the outside air is higher than expected, the pressure gauge detects that the measured value of the LNG pressure has reached the set pressure, and an alarm device. Can generate an alarm. Then, after calling at the nearby primary base 11, the exhaust valve is opened, the vaporized natural gas in the transport tank 15 is recovered, and the LNG pressure in the transport tank 15 can be reduced. The vaporization amount control means 26 can also be activated when the flush gas is collected in the transport tank 15 and the coastal ship 14 is operated.

Subsequently, using the distribution system 10, the liquefied natural gas is delivered to the primary base 11 by the oceangoing vessel 12, then to the secondary base 13 by the coastal vessel 14, and further to the customer 19. A method for delivering liquefied natural gas will be described. (Preparation process) Each primary base 11 is connected to an ocean going ship 12
The NG has been delivered (primary delivery). (Inventory Confirmation and Shipment Forecasting Process) The inventory amount of liquefied natural gas in the storage tank 17 of the secondary base 13 is confirmed by the inventory management means 18, and the secondary base 1
3 to estimate the predicted amount of liquefied natural gas to be sent to the consumer 19. The data of the stock amount and the estimate are sent to the schedule creating means 21, respectively.

(Schedule Creation Step) First, the delivery amount of LNG is calculated by the schedule creation means 21, and then the LNG pressure and the LNG temperature of the transport tank 15 provided on the coastal ship 14 are calculated using the calculation means 16. Calculate the change in the variables. At this time, the LNG of the transport tank 15 is
Also consider the filling rate. Further, the delivery date and time and the time are calculated in consideration of the delivery date and the like, and incorporated into the schedule 23. At this time, if the LNG pressure and the LNG temperature exceed the predetermined values, the LNG filling rate or the like is changed, or the calculation is performed again in consideration of the pressure adjustment by the vaporization amount control unit 26. Further, the temperature and pressure in the storage tank 17 and the stock in the large tank 22 are also added to the schedule 23. The schedule 23 basically includes a monthly schedule created every month and a daily schedule readjusted in consideration of changes in weather, demand and supply. (Delivery process) Primary base 11 according to schedule 23
Then, LNG is loaded into the transport tank 15 of the coastal ship 14, delivered to the secondary base 13 (secondary delivery), and transferred to the storage tank 17. After the transfer, the coastal ship 14 moves to the predetermined primary base 11 according to the schedule 23.

In the delivery process, the vaporization amount control means 26
Is operated to set the pressure in the transport tank 15 during delivery at the time of secondary delivery to a predetermined value or less. That is, when the pressure becomes equal to or higher than the set value as described above on the outgoing route and the return route of the coastal vessel 14, the port calls at the nearby primary base 11 to collect the vaporized natural gas in the transport tank 15. , Reduce pressure. This step is performed in advance according to schedule 2
3, but it is also possible to take measures only in an emergency as a measure against an accident. In the case of an emergency, the schedule is contacted to the schedule creation means 21 and the schedule 23 is reconfigured. (Flash gas recovery step) When the amount of flash gas generated at the secondary base 13 when transferring LNG is large, the flash gas is recovered by the gas recovery means 24 of the coastal ship 14. Then, the flash gas is transported to the primary base 11 by the coastal ship 14 and processed by the processing means of the primary base 11. This process depends on the amount of flash gas generated and the secondary station 1
3 is performed as appropriate according to the scale of the processing equipment. Therefore, this step can be omitted when unnecessary. In this manner, the pressure at the time of delivery by the coastal ship 14 can be managed. (Post-process) The LNG stored in the storage tank 17 of the secondary base 13 is delivered to the customer 19 by tertiary delivery means such as a pipeline or a truck. With this configuration, a large amount of LNG can be delivered to the customer 19 located at a position away from the primary base 11. As described above, the embodiments according to the present invention have been described.
The present invention is not limited to the above embodiment,
For example, although the case where the secondary delivery means is a coastal ship has been described, for example, a land transportation means such as a railroad or a truck may be used. Further, only one of the LNG pressure and the LNG temperature may be considered as a variation factor to be considered when creating a schedule.

[0023]

In the liquefied natural gas delivery method according to the first to fifth aspects, the schedule of the secondary delivery means is determined by changing factors including the LNG pressure and / or LNG temperature of the transport tank, and the inside of the storage tank. Of LNG from the secondary terminal and the predicted amount of LNG sent out from the secondary terminal to the customer.
Can be transported at low cost. In particular, in the liquefied natural gas delivery method according to claim 2, when the schedule of the secondary delivery means is created, the LN of the transport tank is used.
Since the G filling rate is also taken into account, changes in pressure and temperature rise can be accurately predicted, and a schedule can be created with high accuracy. In the liquefied natural gas delivery method according to claim 3, the flash gas generated at the secondary terminal is collected and processed at the primary terminal, so that the processing can be performed reliably.
In addition, since the flash gas can be used for other operations at the primary base, the waste can be prevented from being wasted, and the operations can be performed efficiently. In the liquefied natural gas delivery method according to the fourth aspect, the pressure in the transport tank during delivery at the time of the secondary delivery is set to a predetermined value or less, so that the pressure increase in the transport tank is suppressed and LNG is reduced. Can be transported up to a distance. In the liquefied natural gas delivery method according to the fifth aspect, since the secondary delivery means is a coastal ship, LN
G can be transported in large quantities. In the liquefied natural gas delivery system according to claims 6 to 10, calculation means for predicting a change in a variation factor including LNG pressure and / or LNG temperature of the transport tank, and inventory of the liquefied natural gas in the storage tank Since it has inventory management means for grasping the quantity, shipment forecasting means for estimating the predicted quantity of LNG sent from the secondary base to the customer, and schedule creation means for creating a schedule for the secondary delivery means, the transportation tank It is possible to calculate the expected pressure increase in the inside, reliably perform pressure management during transportation, and prevent accidents such as damage to containers due to the pressure increase. In particular, in the liquefied natural gas delivery system according to the seventh aspect, since the LNG filling rate of the transport tank is included in the fluctuation factor, the expected rising pressure of the transport tank can be calculated more accurately. Claim 8
In the liquefied natural gas delivery system described above, the secondary delivery means is provided with gas recovery means for recovering flash gas generated at the secondary terminal, and the primary terminal is provided with processing means for processing the recovered flash gas. The amount of heat generated by burning the flash gas can be taken out, and the generated flash gas can be used effectively.
In the liquefied natural gas delivery system according to the ninth aspect, since the secondary delivery means is provided with the vaporization amount control means for setting the vaporization amount of the liquefied natural gas being delivered to a predetermined value or less, the pressure in the transport tank is reduced. It is possible to prevent the transport tank from being damaged by controlling the rise and to carry out the transport stably. And
In the liquefied natural gas delivery system according to the tenth aspect, since the secondary delivery means is a coastal ship, a large amount of liquefied natural gas can be carried at once, and the transportation efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a transportation route of a liquefied natural gas delivery system according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a data flow of the delivery system.

FIG. 3 is a view showing a fully loaded L by a calculating means of the delivery system;
It is an expected graph of the change of NG temperature, and the change of LNG pressure.

FIG. 4 shows an empty state L by a calculating means of the delivery system.
It is an expected graph of the change of NG temperature, and the change of LNG pressure.

FIG. 5 is an explanatory diagram of a schedule created by schedule creating means of the delivery system.

[Explanation of symbols]

10: delivery system, 11: primary base, 12: oceangoing vessel (primary delivery means), 13: secondary base, 14: coastal vessel (secondary delivery means), 15: transport tank, 16: calculation means,
17: Storage tank, 18: Inventory management means, 19: Consumer, 20: Shipment prediction means, 21: Schedule creation means, 22: Large tank, 23: Schedule, 24: Gas recovery means, 25: Processing means, 26 : Vaporization control means

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Keiji Nakanishi 1-1, Tobata-cho, Tobata-ku, Kitakyushu-shi, Fukuoka New Nippon Steel Corporation Yawata Works (72) Inventor Kazuo Watanabe 2, Otemachi 2 Chiyoda-ku, Tokyo 6th-3rd New Nippon Steel Corporation F-term (reference) 3J071 AA23 BB11 DD28 EE01 EE19 FF03

Claims (10)

[Claims] 1. A method for delivering liquefied natural gas, comprising: delivering liquefied natural gas to a primary base by a primary delivery means, delivering the liquefied natural gas to a secondary base by a secondary delivery means, and further delivering the liquefied natural gas to a customer. The schedule of the secondary delivery means is set to the LN of the transport tank provided in the secondary delivery means.
Variable factors including G pressure and / or LNG temperature, the amount of liquefied natural gas in the storage tank of the secondary terminal, and the estimated amount of liquefied natural gas sent from the secondary terminal to the customer are considered. A method for delivering liquefied natural gas, characterized in that the pressure is controlled during delivery by the secondary delivery means. 2. The liquefied natural gas delivery method according to claim 1, wherein when the schedule of the secondary delivery means is created, an LNG filling rate of the transport tank is taken into account. Shipping method. 3. The method for distributing liquefied natural gas according to claim 1, wherein the flash gas generated at the secondary base is transferred when the liquefied natural gas is transferred from the secondary delivery means to the secondary base. A method for delivering liquefied natural gas, comprising: collecting and transporting the flash gas to the primary base by the secondary delivery means; and treating the flash gas at the primary base. 4. The liquefied natural gas delivery method according to claim 1, wherein the pressure in the transport tank during delivery is set to a predetermined value or less. Gas delivery method. 5. The liquefied natural gas delivery method according to claim 1, wherein the secondary delivery means is a coastal vessel. 6. A primary delivery means for delivering liquefied natural gas to a primary base, a secondary delivery means for delivering the liquefied natural gas from the primary base to a secondary base, and a transport provided in the secondary delivery means Calculating means for predicting a change in a fluctuation factor including LNG pressure and / or LNG temperature of the storage tank, inventory management means for ascertaining the amount of liquefied natural gas in the storage tank at the secondary base, Shipment forecasting means for estimating the estimated amount of liquefied natural gas sent from the base to the consumer,
The schedule of the secondary delivery unit is considered in consideration of the change of the fluctuation factor predicted by the calculation unit, the liquefied natural gas inventory amount grasped by the inventory management unit, and the predicted delivery amount estimated by the shipment prediction unit. A liquefied natural gas distribution system, comprising: 7. The liquefied natural gas delivery system according to claim 6, wherein said calculating means predicts a change in a variation factor in consideration of an LNG filling rate of said transport tank provided in said secondary delivery means. A liquefied natural gas delivery system characterized by performing: 8. The liquefied natural gas delivery system according to claim 6, wherein said secondary delivery means is provided with gas recovery means for recovering flash gas generated at said secondary base, and said primary base is provided with a gas recovery means. , A processing system for processing the recovered flash gas is provided. 9. The liquefied natural gas delivery system according to claim 6, wherein the secondary delivery means sets a vaporized amount of the liquefied natural gas during delivery to a predetermined value or less. A liquefied natural gas delivery system comprising a quantity control means. 10. The liquefied natural gas delivery system according to claim 6, wherein said secondary delivery means is a coastal vessel.