FR3034746A1 - EMBARKATION AND METHOD OF SUPPLYING LIQUEFIED NATURAL GAS - Google Patents

Abstract

The liquefied natural gas refueling vessel (10) comprises: at least one first reservoir (105) of liquefied natural gas, integral with the boat, for storing liquefied natural gas at a first pressure; a second removable tank (110) of liquefied natural gas for storing natural gas at a pressure higher than the first pressure; - means for displacing (115) a portion of the liquefied natural gas from a first reservoir to a second reservoir; reservoir, said displacement means comprising means (120) for compressing the displaced liquefied natural gas and means (125) for fixing each second reservoir to a storage surface of the boat.

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to a liquefied natural gas refueling vessel and a liquefied natural gas refueling method. It applies in particular to the refueling of ships using liquefied natural gas as fuel. STATE OF THE ART The introduction of the international MARPOL (Marine Pollution) regulation aims to reduce sulfur emissions from ships in the SECA zones Emission Control Areas ", such as the North Sea, the Baltic Sea and the Channel from January 2015. This regulation is also aimed at tightening regulations on greenhouse gas emissions. greenhouse effect.

These two constraints have the effect of promoting liquefied natural gas (hereinafter abbreviated as "LNG") as an alternative to diesel fuel, especially for maritime or river use. The weakness of LNG as an alternative is mainly based on the current lack of distribution and supply infrastructure for boats. In particular, the distribution and supply of LNG are all the more difficult as the boats do not all implement the same standard. Some vessels use LNG tanks at atmospheric pressure and other vessels use pressurized LNG tanks. In some systems, tanker ships transfer LNG from their tanks to the ships' tanks. The disadvantage of these systems is that the supply vessels present tanks of LNG either at atmospheric pressure or pressurized, which complicates the compatibility between these vessels and ships that are not of the same type.

In other systems, distribution stations, including an LNG storage tank and an LNG transfer means, are positioned in ports. These distribution stations require a very high investment, which prevents the availability of this solution for all ports.

5 For all of these reasons, there is currently no single solution for refueling ships in LNG, pressurized or not, not requiring docking of these ships in a port equipped with a distribution station . OBJECT OF THE INVENTION The present invention aims to remedy all or part of these disadvantages. For this purpose, according to a first aspect, the present invention is directed to a liquefied natural gas refueling vessel, which vessel comprises: at least one liquefied natural gas reservoir, integral with the vessel, for storing liquefied natural gas at a first pressure, at least one second removable tank of liquefied natural gas for storing natural gas at a pressure greater than the first pressure; means for displacing a portion of the liquefied natural gas from a first reservoir; to a second reservoir, said displacement means comprising a means for compressing displaced liquefied natural gas and - a means for attaching each second reservoir to a storage surface of the vessel. With these provisions, the boat has two types of tank: a type filled with pressurized LNG and a type filled with non-pressurized LNG, for example. In this way, the boat can refuel vessels operating with pressurized LNG and ships operating with non-pressurized LNG. In addition, the pressurized LNG is obtained from non-pressurized LNG, which allows a supply of the boat object of the invention only in non-pressurized LNG. Finally, the mobile nature of each second tank allows the use of these tanks as transportable refills from the refueling boat to another vessel. In embodiments, the moving means includes a liquefied natural gas transfer line from a first tank to a tank, another vessel, for storing liquefied natural gas at the first pressure.

These embodiments make it possible to transfer LNG from the refueling boat to a tank of another boat, this LNG being for example at atmospheric pressure. In embodiments, the displacement means is configured to supply a tank, separate from the boat, in liquefied natural gas at the first pressure. These embodiments make it possible to transfer LNG from the refueling boat to a tank of another boat, this LNG being pressurized. In embodiments, at least one second reservoir has standardized dimensions. These embodiments make it possible to use mobile tanks of standardized dimensions so as to allow transport and manufacture of facilitated means of transport. In embodiments, the pressure of the liquefied natural gas present in at least one second reservoir is between 2 and 25 bar. These embodiments make it possible to pressurize LNG at a pressure usually used by vessels using pressurized LNG as a fuel. In embodiments, the craft object of the present invention comprises: a means for capturing evaporation gas of the liquefied natural gas present in a first reservoir, a means for compressing the evaporation gas captured and means for supplying the evaporation gas compressed to a second reservoir. These embodiments give the boat the ability to process and dispose of evaporation gases for useful purposes. In embodiments, the craft object of the present invention comprises means for cooling the evaporation gas captured before compression. These embodiments make it possible to compress the evaporation gas at the pressure of the LNG contained in a second tank.

In embodiments, the cooling means comprises means for mixing evaporation gas captured with liquefied natural gas. These embodiments allow for low cost cooling of the evaporation gas.

These embodiments allow a separation between the recovered evaporation gas and the LNG stored in the tanks of the boat. According to a second aspect, the present invention aims at a liquefied natural gas refueling process, which comprises: a first step of filling at least a first tank of liquefied natural gas integral with a refueling vessel for storing liquefied natural gas at a first pressure; - a second step of filling at least a second removable liquefied natural gas reservoir of a refueling boat to store natural gas at a pressure greater than the first pressure, which comprises a step of moving a portion of the liquefied natural gas, from a first reservoir to a second reservoir, the displacement step comprising a step of compressing the displaced gas and - a step of fixing each second reservoir to a surface storage of the boat.

Since the aims, advantages and particular characteristics of the process which are the subject of the present invention being similar to those of the boat which is the subject of the present invention, they are not recalled here. In embodiments, the method which is the subject of the present invention comprises a step of setting the boat in motion carried out at least in part simultaneously with the secondary filling step. These embodiments allow, from a single feeding step during which the boat is stationary, to move the boat and simultaneously fill a second tank. The rotation of the boat is thus improved.

BRIEF DESCRIPTION OF THE FIGURES Other particular advantages, aims and features of the invention will be apparent from the following nonlimiting description of at least one embodiment of the invention and method of the present invention, with reference to the accompanying drawings, in which: FIG. 1 is a diagrammatic and sectional view of a particular embodiment of the craft object of the present invention and FIG. 2 represents, in the form of a logic diagram, steps of FIG. a particular embodiment of the method which is the subject of the present invention. DESCRIPTION OF EXAMPLES OF THE INVENTION This description is given in a nonlimiting manner, each feature of an embodiment being combinable with any other feature of any other embodiment in an advantageous manner. Note that the term "one" is used in the sense of "at least one". As of now, we note that the figures are not to scale. FIG. 1, which is not to scale, shows a sectional view of an embodiment of the boat 10 which is the subject of the present invention. This liquefied natural gas refueling boat 10 comprises: at least one first tank 105 of liquefied natural gas, integral with the boat, for storing liquefied natural gas at a first pressure; at least one second removable tank 110; liquefied natural gas for storing natural gas at a pressure higher than the first pressure, means for displacing a portion of the liquefied natural gas from a first reservoir to a second reservoir, said moving means comprising a means 120 compressing the displaced liquefied natural gas and means 125 for attaching each second reservoir to a storage surface of the boat. Each first reservoir 105 is, for example, a closed vessel having a tank supply valve through an LNG supply line. The LNG stored in each first tank 105 is, for example, stored at atmospheric pressure.

The total storage volume of all the first tanks 105 is, for example, between 1,000 and 20,000 cubic meters. In variants, the boat 10 comprises a single first tank 105 of significant dimensions compared to the storage volume dimensions of the second tanks 110, that is to say having a storage volume equal to half the total volume of storage of all the tanks, 105 and 110, of the boat 10. In variants, the LNG stored in a first tank 105 is stored at a pressure lower than the pressure of the second tanks 110. Each second tank 110 is for example, a tank having a container shape. Each second tank 110 has a feed opening (not shown) that can be connected to a supply line. Each second tank 110 comprises a means of attachment 125 to the boat 10. This attachment means 125 is, for example, an assembly formed by chaining and rings connecting the second tank 110 to the boat 10. The attachment each second tank 110 is made, for example, by the implementation of a crane present on a wharf, on a nearby ship or on the boat 10 itself.

Each second tank 110 may be attached to the vessel 10 empty, partially filled or filled completely with LNG. In embodiments, such as the embodiment shown with reference to FIG. 1, at least one second tank 110 has standardized dimensions, notably allowing the transport of this tank on a truck.

The displacement means 115 is, for example, an LNG pump drawing LNG at atmospheric pressure from a first tank 105 to move this LNG into a second tank 110. Before being moved, the LNG is compressed by the means 120. The compression means 120 is, for example, the pump performing the displacement of the LNG. LNG is compressed at a pressure greater than the first pressure. For example, this LNG is compressed at a pressure of between 2 bars and 25 bars. In embodiments, such as the embodiment shown in FIG. 1, the displacement means 115 includes a line 130 for transferring the liquefied natural gas from a first reservoir 105 to a tank (not shown), a reservoir other craft (not shown) for storing liquefied natural gas at first pressure. This transfer line 130 allows the LNG feed of a vessel operating on the basis of LNG at atmospheric pressure. The transfer of LNG carried out in this transfer line 130 is set in motion, for example, by the displacement means 115. In these variants, the boat 110 comprises a means for selecting a pipe supplied by the means of transport. 115. In variants, the transfer pipe 130 is merged with a pipe for feeding a second tank 110, this transfer pipe 130 being movable from a second tank to the tertiary tank. To carry out this transfer, the boat 10 is approached to the vessel to be refueled LNG and the transfer pipe 130 is attached to an opening of the tank in which the LNG is transferred.

In embodiments, such as the embodiment shown in FIG. 1, the displacement means 115 is configured to feed a tank (not shown), distinct from the boat 10, into liquefied natural gas at the first pressure. The displacement means 115 feeds this tank by the implementation of a feed means 135. This supply means is, for example, a transfer line similar to the transfer line 130. The compression means 140 is, for example, similar to the compression means 120. In variants, the transfer line 130 and / or the feed means 135 are supported by an articulated arm.

In variants, this feed means 135 comprises a compression means 140. In variants, the compression means 140 and the compression means 120 are combined, the feed means 135 implementing the displacement means 115. to feed the compression means 120 and the tank of the other boat.

To achieve this supply, the boat 10 is approached to the boat to be refueled LNG and the transfer pipe 130 is attached to an opening of the tank in which the LNG is fed. In variants, the feed is made by transferring a second tank 110 from the boat 10 to the boat to be refueled. This transfer is carried out, for example, by the implementation of a crane moving the second tank 110 to the boat to be refueled. This second tank 110 is then connected by a pipe to an internal propulsion system of the boat to supply the system with pressurized LNG.

In embodiments, such as the embodiment shown in FIG. 1, the boat 10 comprises: a means 145 for capturing the evaporation gas of the liquefied natural gas ("boiloff gas" in English) present in a first reservoir 105, a means 150 for compressing the evaporation gas captured and a means 155 for supplying the compressed evaporation gas to a second reservoir 110. The gas capture means 145 is, for example, similar to an extractor hood evaporation gas more volatile than LNG.

The compression means 150 is, for example, a compressor. The feed means 155 is, for example, similar to the displacement means 115. In variants, the feed means 155 and the displacement means 115 are combined. The transfer of the evaporated gases, stored at the pressure of the first tank, that is to say at a pressure close to atmospheric pressure and then the compression of said gases causes their liquefaction. In variants, the boat 10 comprises a means 160 for cooling the evaporation gas captured before compression. This cooling means 160 is, for example, a heat exchanger. This heat exchanger cools the evaporation gas captured at a temperature below -160 ° C, for example. In variants, this cooling means 160 comprises means 165 for mixing the evaporation gas captured with LNG contained in a first reservoir 105, this LNG having a temperature below the temperature of the evaporation gas. This mixing means 165 is, for example, a pump sucking a portion of the LNG from a first reservoir 105 for transferring this sucked LNG to a pipe or tank containing the evaporation gas. FIG. 2 shows a particular embodiment of the method 20 of the present invention. This liquefied natural gas refueling method comprises: a first filling stage 605 of at least a first tank of liquefied natural gas secured to a refueling boat for storing liquefied natural gas at a first pressure a second step 610 of filling at least a second removable reservoir 5 of liquefied natural gas of a refueling boat for storing natural gas at a pressure greater than the first pressure, which comprises a step 615 of displacement of part of the liquefied natural gas, from a first reservoir to a second reservoir, the displacement step comprising a displaced gas compression step 620 and a step 625 of attaching each second reservoir to a storage surface of the boat. The filling step 605 is carried out, for example, by the implementation of an LNG transfer line from an external source to a first reservoir as described with reference to FIG. 1, for example. This external source 15 is, for example, a stationary distribution station or a refueling boat. The filling step 610 comprises the displacement step 615 and the compression step 620. The displacement step 615 is carried out, for example, by the implementation of a pump sucking a part of the LNG in a first stage. tank. The compression step 620 is performed, for example, by the pump moving and compressing the LNG. The fixing step 625 is performed, for example, by the implementation of chaining and rings to fix at least a second reservoir to a support surface of the boat. In embodiments, such as the embodiment shown in FIG. 2, the method 20 includes a step 630 of setting the boat in motion performed at least partially simultaneously with the secondary filling step 610. The step of setting in motion 630 is carried out, for example, by the implementation of a motor or a means of propulsion of the boat.

Thus, as understood from reading the present description, the boat and the method which are the subject of the present invention make it possible, thanks to a single LNG feed, to be able to supply LNG at two different pressures. These two pressures correspond to the pressures used by ships using LNG as a fuel. The loading and unloading of second reservoirs makes it possible, in addition, to create ad-hoc distribution stations from a set of second tanks and a means for extracting the LNG contained in these tanks.

Four types of circuit can thus be implemented: a first circuit for compressing the LNG and moving it from a first tank to a second tank; a second circuit for compressing the LNG and moving it from a first tank to a second tank outside the boat, 10 - a third circuit to move the LNG from a second tank to another second tank outside the boat and - a fourth circuit to move the LNG from one tank to another first tank outside the boat. Each of these circuits may be distinct from the other circuits or comprise common elements, such as the displacement means 115 described with reference to FIG. 1. The presence of at least one second reservoir and means configured to fill them during navigation. of the boat saves time. Indeed, the compression of LNG is a long process. Pressurizing the LNG 20 on the boat saves time in the service. In addition each second tank can then be delivered directly, by exchange with a second empty tank. Advantageously, a fifth circuit makes it possible to recover and compress the evaporation gas in a first tank and transfer it to a second tank. The evaporation gas is liquefied during compression.

Claims (8)

REVENDICATIONS1. Boat (10) for refueling liquefied natural gas, craft characterized in that it comprises: at least a first tank (105) of liquefied natural gas, integral with the boat, for storing liquefied natural gas at a first pressure at least one second removable reservoir (110) of liquefied natural gas for storing natural gas at a pressure higher than the first pressure, means for displacing (115) a portion of the liquefied natural gas, a first reservoir to a second reservoir, said displacement means comprising means (120) for compressing the liquefied natural gas displaced and means (125) for fixing each second reservoir to a storage surface of the boat. 2. Craft (10) according to claim 1, wherein the displacement means (115) comprises a pipe (130) for transferring liquefied natural gas from a first tank (105) to a tank, another boat, to store the liquefied natural gas at the first pressure. 3. Craft (10) according to one of claims 1 or 2, wherein the displacement means (115) is configured to supply a reservoir, separate from the boat, liquefied natural gas at the first pressure. 4. Craft (10) according to one of claims 1 to 3, wherein at least a second tank (110) has standardized dimensions. 5. Craft (10) according to one of claims 1 to 4, wherein the pressure of the liquefied natural gas present in at least a second tank (110) is between 2 and 25 bar. 6. Craft (10) according to one of claims 1 to 5, which comprises: - means (145) for capturing evaporation gas liquefied natural gas present in a first reservoir (105), 3034746 12 - a means (150) for compressing evaporation gas captured and - means (155) for supplying compressed evaporation gas to a second reservoir (110). 5 7. A method (20) for refueling liquefied natural gas, characterized in that it comprises: - a first step (605) for filling at least a first liquefied natural gas tank secured to a refueling boat for storing liquefied natural gas at a first pressure; 10 - a second step (610) for filling at least a second removable liquefied natural gas reservoir of a refueling vessel to store natural gas at a pressure greater than the first pressure, which comprises a step (615) for moving a portion of the liquefied natural gas from a first reservoir to a second reservoir, the displacement step comprising a step (620) for compressing the displaced gas, and - A step (625) for fixing each second reservoir to a storage surface of the boat. The method (20) of claim 7 which comprises a step (630) of moving the boat at least partially simultaneously with the secondary filling step (610).