FR3004514A1 - IMPROVED SYSTEM FOR PROCESSING AND DELIVERING NATURAL GAS COMPRISING A CIRCUIT FOR HEATING THE TANK - Google Patents

Abstract

The invention relates to a system for treating and transporting natural gas comprising: - a power supply circuit of a power generation equipment selected from a heat engine, a fuel cell, or a gas turbine to conveying natural gas from a tank (2) for storing liquefied natural gas to said power generation equipment (4, 6), said supply circuit comprising an upstream portion connected to the tank (2) and a portion downstream connected to the power generation equipment (4, 6); a feed circuit of a burner (5) for conveying natural gas from the tank (2) to the burner (6) comprising an upstream portion connected to the tank (2) and a downstream portion connected to the burner ( 5); a heating circuit of the tank (2) capable of collecting a gaseous flow in the lower part of the tank (2) and injecting it into the upper part of the tank (2), said heating circuit comprising a connected upstream portion a pipe (52) opening in the lower part of the tank (2) and a downstream portion connected to a pipe (71) opening in the upper part of the tank (2).

Description

TECHNICAL FIELD The invention relates to the field of ships comprising a liquefied natural gas storage tank. The invention relates more particularly to an on-board system for the treatment and transport of natural gas for the supply of natural gas to power generation equipment, such as a heat engine, a fuel cell or a gas turbine, and the heating of a tank, in particular to allow its inspection. BACKGROUND In the state of the art, it is known vessels having a liquefied natural gas storage tank and a system for treating and transporting gas from the tank to one or more power generation equipment. , such as heat engines, fuel cells or gas turbines and / or to one or more burners of a power plant.

Such vessels are subject to particularly thorough control and maintenance operations. In particular, liquefied natural gas storage tanks are regularly inspected. To do this, the tanks are emptied and heated to reach appropriate temperatures to allow such inspections.

SUMMARY An idea underlying the invention is to propose an improved system for treating and conveying natural gas that can supply, on the one hand, a power generation equipment chosen from a heat engine, a battery combustion and a gas turbine and, secondly, a burner and which further allows efficient heating of the tank. According to one embodiment, the invention provides a system for treating and transporting natural gas comprising: a supply circuit of a heat engine of a power generation equipment selected from a heat engine, a battery combustion engine, or a gas turbine for conveying natural gas from a liquefied natural gas storage tank to said power generation equipment, said supply circuit having an upstream portion connected to the vessel and a downstream portion connected to the power generation equipment; - A burner supply circuit for conveying natural gas from the tank to the burner having an upstream portion connected to the tank and a downstream portion connected to the burner; a heating circuit of the vessel able to collect a gaseous flow in the lower part of the tank and to inject it into the upper part of the tank, said heating circuit comprising an upstream portion connected to a pipe opening at the bottom of the tank; tank and a downstream portion connected to a pipe opening into the upper part of the tank; wherein: the power supply circuit of the power generation equipment and the heating circuit comprise a common circuit portion which includes a compressor having an input and an output and for increasing the pressure and temperature of a gas flow, said common portion being delimited, upstream, by a first switchable three-way connection device for selectively connecting the upstream portion of the motor supply circuit or the upstream portion of the heating circuit to the input of the compressor and, downstream, by a second switchable second connection member for selectively connecting the compressor output to the downstream portion of the power supply circuit of the power generation equipment or to the downstream portion of the power supply circuit. heater ; the downstream portion of the heating circuit comprising a third three-way connection device for connecting said downstream portion of the heating circuit to the downstream portion of the burner supply circuit so as to evacuate a portion of the gas flow conveyed into the circuit heating to the burner. Such a system is particularly advantageous in that, on the one hand, it effectively heats the liquefied natural gas storage tank while valuing the natural gas discharged from the tank, and, on the other hand, it has a design optimized to allow use of components, such as the compressor, to provide many of the system features. According to embodiments, such a system for treating and transporting natural gas may comprise one or more of the following characteristics. the downstream portion of the heating circuit comprises a connection section at the outlet of the compressor and a return section to the tank and the downstream portion of the heating circuit and the burner supply circuit comprise a common portion which comprises a gas heating having an inlet and an outlet, said common portion being delimited, upstream by a fourth switchable three-way connection device for selectively connecting the upstream portion of the burner supply circuit or the connection section to the outlet of the heating circuit compressor at the inlet of the heating apparatus and, downstream, by the third three-way connection member which makes it possible to concomitantly connect the outlet of the gas heater to the downstream portion of the burner feed circuit and the return section to the heating circuit tank. the system comprises a switchable three-way connection device making it possible to selectively connect said pipe opening into the upper part of the tank, on the one hand, to the downstream portion of the heating circuit so as to allow an injection of the gaseous flow in the upper part. of the tank or, on the other hand, to the upstream portion of the power supply circuit of the power generation equipment and / or to the upstream portion of the burner supply circuit in order to allow collection of the gas, evaporated in the tank. the system comprises a tank filling circuit and a switchable three-way connection device making it possible to selectively connect said duct opening in the lower part of the tank, on the one hand, to the upstream portion of the heating circuit so as to allow a gas flow collection in the lower part of the tank or, on the other hand, to the filling circuit of the tank. the power supply circuit of the power generation equipment comprises a phase separator connected downstream, on the one hand, to a return duct making it possible to return, in the form of condensate, to the tank, a heavy fraction natural gas comprising the hydrocarbons having the longest carbon chain and, secondly, a duct connected to the compressor inlet to conduct a light fraction of the natural gas comprising the hydrocarbons having the shortest carbon chain. the burner supply circuit bypasses said phase separator. the compressor is a typical multi-stage compressor. the system comprises a compressor protection device, said protection device comprising, a recirculation loop equipped with a valve for returning upstream of the compressor a gaseous stream collected downstream of said compressor. the circuit portion common to the power supply circuit of the power generation equipment and the heating circuit comprises a plurality of compressors arranged in parallel. According to one embodiment, the invention relates to a vessel comprising a liquefied gas storage tank, a power generation equipment selected from a heat engine, a fuel cell and a gas turbine, a production plant of energy equipped with a burner and a system for treating and transporting natural gas as mentioned above. In one embodiment, the power generation equipment is for propelling the ship.

According to one embodiment, the invention also relates to a method of filling the vessel of a vessel as mentioned above in which a fluid is conveyed through isolated pipes from a floating or land storage facility to the tank of the ship. According to one embodiment, the invention also relates to a system comprising a ship as mentioned above, insulated pipes arranged to connect the tank installed in the hull of the ship to a floating or ground storage facility and a pump. to entrain a flow of fluid through the isolated pipes from the floating or ground storage facility to the vessel vessel.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be better understood, and other objects, details, features and advantages thereof will become more clearly apparent from the following description of several particular embodiments of the invention, given solely for the purposes of the invention. illustrative and not limiting, with reference to the accompanying drawings. - Figure 1 is a schematic view of a system for processing and transporting natural gas onboard a ship. FIG. 2 illustrates the system of FIG. 1, in which a path of natural gas for supplying power generation equipment for the propulsion of the ship and for feeding a production equipment of energy for electricity generation is highlighted by a highlight. FIG. 3 illustrates the system of FIG. 1, in which a path of the natural gas for supplying power generation equipment for the generation of electricity is highlighted by a highlighting. - Figure 4 illustrates the system of Figure 1, wherein a natural gas path to a burner of an energy production facility for the recovery of the heavy fraction of natural gas is highlighted. - Figure 5 illustrates the system of Figure 1, wherein a path of natural gas, evaporated in the tank to the burner of the power generation facility is highlighted. FIG. 6 illustrates the system of FIG. 1, in which a path of the natural gas during the implementation of a method of heating the tank is highlighted. - Figure 7 illustrates a vessel equipped with a gas storage tank and natural gas-fired power generation equipment for the propulsion of the ship.

DETAILED DESCRIPTION OF EMBODIMENTS In the description and claims, the terms "upstream" and "downstream" are defined relative to the direction of flow of the natural gas. FIG. 7 represents a vessel 1 equipped with one or more liquefied natural gas storage tanks 2 and a power train comprising one or more power generation equipment 4, chosen from heat engines, fuel cells or gas turbines, powered by natural gas. Such a vessel 1 may in particular be a LNG carrier for the transport of liquefied natural gas, but may also be intended for all other applications. For example, it may be a cargo ship, a passenger ship, a fishing vessel or others.

FIG. 1 represents a tank 2 for storing natural gas and a system 3, on board the ship 1, for processing and conveying natural gas. The system 3 for treating and transporting natural gas is suitable for supplying power generation equipment 4 of the powertrain, as shown in FIG. 2, for supplying a burner 5, as shown in FIGS. 4, 5 and 6 and, optionally, for the supply of another power generation equipment, such as a heat engine, a combustion cell or a gas turbine 6 of a electric generator, as shown in Figures 2 and 3.

The tank 2 is a sealed and thermally insulating tank adapted for the storage of liquefied natural gas (LNG). The tank 2 may in particular be of the membrane type for storing liquefied natural gas at atmospheric pressure. The power generation equipment 4 of the powertrain is selected from heat engines, fuel cells and gas turbines.

When the power generation equipment 4 is a heat engine, the engine can be mixed diesel-natural gas feed. Such engines 4 can operate either in diesel mode in which the engine is fully powered by diesel or in natural gas mode in which the engine fuel is mainly made of natural gas while a small amount of pilot diesel is injected to initiate combustion. The output shaft associated with the mechanical energy generated by the power generation equipment 4 may be coupled to one or more propellers for the propulsion of the ship, or may be coupled to an alternator for transforming the mechanical energy. in electrical energy, the electrical energy being in this case used for powering an electric motor coupled to a propeller for the propulsion of the ship. In this latter alternative, if a heat engine is applied, it can in particular be a DFDE technology engine for "Dual Fuel Diesel Electric" in English. The power generation equipment 6 for the generation of electricity 30 may be a diesel-natural gas mixed-feed heat engine, for example of the DFDE type, a combustion cell or a gas turbine. The burner 5 is integrated in a power generation facility. The energy production facility may include a boiler for steam production. The steam may be for supplying steam turbines for power generation and / or for supplying a heating network of the ship 1. FIG. 2 illustrates two circuits respectively supplying the power generation equipment 4 of the group power plant and power generation equipment 6 for power generation. The circuit supplying power generation equipment 4 to the powertrain will subsequently be designated "main circuit" while the circuit supplying the power generation equipment 6 for power generation will be referred to as "circuit". secondary education ". Note that the main circuit can also be used to route the natural gas to the secondary circuit. Such an arrangement makes it possible to ensure redundancy of the supply of the secondary circuit, so as to overcome any malfunctions. The main circuit comprises a suction pipe 7a opening towards the bottom of the tank 2 and supplied by a pump 8a. The suction pipe 7a conducts the liquefied natural gas to a three-way connection 23 for connecting the suction pipe 7a, on the one hand, to a pipe 24, equipped with a valve 123, connected to the inlet a forced evaporation plant 9a, also called an evaporator, and on the other hand to a pipe 25, equipped with a valve 223, connected to a sprayer 10a. The forced evaporation plant 9a makes it possible to convert the liquefied natural gas into a gas stream. The output of the forced evaporation plant 9a is connected via a conduit 26 to the sprayer 10a to drive the gas flow to said sprayer 10a. The sprayer 10a is capable of spraying, in the gas stream, obtained at the outlet of the forced evaporation plant 9a, liquefied natural gas collected upstream of said forced evaporation plant 9a. The sprayer 10a thus makes it possible to cool the gas stream so that the heavier hydrocarbons, that is to say those having the longest carbon chain and the highest evaporation temperatures, condense. The gas stream is typically cooled to below -100 ° C. At the outlet of the sprayer 10a, the gaseous stream loaded with suspended natural gas droplets is led to a phase separator 11a via the pipe 27. This phase separator 11a, sometimes called mist separator, or "mist separator" in the English language , allows to separate the liquid phase from the gas phase. The liquid phase consists of a heavy fraction of natural gas comprising the heavier hydrocarbons, that is to say having the longest carbon chain. The heavy fraction of the natural gas is returned in the form of condensates to the storage tank 2 via a condensate return line 12a. The condensate return line 12a is equipped with a condensate recovery container 72a which is regularly purged when its condensate level reaches a threshold. The gaseous phase, consisting of the light fraction of the natural gas comprising the hydrocarbons having the shortest carbon chain, is itself conducted, via the pipe 28, to a gas heating apparatus 13 for heating the gas phase to a gas typical temperature of 30 ° C. Such a gas heater 13 is typically a gas / liquid or gas / gas heat exchanger. The gas heater 13 is here equipped with a recirculation loop 29.

Finally, at the outlet of the gas heating apparatus 13a, the gas flow can be led to the power generation equipment 4 of the powertrain via the pipe 30. Similarly, the secondary circuit comprises a pipe of suction 7b opening towards the bottom of the tank 2 and fed by a pump 8b. The suction pipe 7b makes it possible to bring the liquefied natural gas to a forced evaporation plant 9b and to two sprayers 10b and 31. To do this, the suction pipe 7b is connected via a three-way connection 32, d firstly to a pipe 33, equipped with a valve 132, leading to a sprayer 31 and, secondly, to a pipe 34, equipped with a valve 232, and itself connected to a three-way connection 35 making it possible to connect said duct 34, on the one hand, to the sprayer 10b via the duct 36, equipped with a valve 135 and, on the other hand, to the inlet of the forced evaporation plant 9b via the duct 17 equipped with a valve 235. The output of the forced evaporation plant 9b is connected by a series of lines 37, 38, 39 to the sprayers 10a, 31 for spraying liquefied natural gas so as to condense the most hydrocarbons. heavy. The gas stream at the outlet of the sprayer 31 is led to the inlet of a phase separator 11b via a pipe 40.

Similarly, the phase separator 11b makes it possible to separate the liquid phase from the gaseous phase and to return the condensates to the tank 2 via a condensate return line 12b. The condensate return line 12b is equipped with a condensate recovery container 72b which is regularly purged when its condensate level reaches a threshold. On the other hand, at the outlet of the phase separator 11b, the gas phase, consisting of the light fraction of the natural gas, is conducted via a pipe 42 to one or more compressors 16a, 16b arranged in parallel. In order to allow the flow of gas flow, in parallel, to several compressors 16a, 16b, the pipe 42 is provided with one or more multi-channel connections 43 leading to pipes equipped with valves 143, 243. In the figure 2, the gas flow is conducted through one of the two compressors 16a, 16b. However, depending on the supply flow setpoint of the power generation equipment 4 or 6, it may be envisaged to pass the gas flow, in parallel, through the two compressors 16a, 16b. For example, the compressors 16a, 16b are multi-stage compressors, for heating the gas flow and compressing it to pressures compatible with the specifications of the power generation equipment 6 supplied with natural gas, for example of the order of 5 to 6 absolute bar for DFDE type heat engines. The compressor 16a, 16b may be a volumetric compressor, a centrifugal compressor or any other type compatible with the input supply pressures of a heat engine, a fuel cell, or a gas turbine.

Advantageously, the system 3 is equipped with an anti-instability protection device or "anti-surge" to protect the compressor 16a, 16b against low input volume flow regimes. Such a device comprises, at the output of the compressor 16a, 16b, a recirculation loop 44 which makes it possible to return a portion of the compressed gas flow, upstream of said compressor 16. The recirculation loop 44 is equipped with a valve 18a, 18b allowing to control the flow rate in the recirculation loop 44. In the embodiment shown, the recirculation loop 44 is connected to a pipe 14, whose arrangement will be described later.

At the output of the compressor (s) 16a, 16b, the gas flow is led to a cooling apparatus 19 for controlling the temperature of the gas stream at a set temperature. When the system comprises several compressors 16a, 16b in parallel, the outputs of said compressors 16a, 16b are connected to the inlet of the cooling apparatus 19 via three-way connections 45, 63. Finally, at the output of the cooling device 19, the gas stream is led to the power generation equipment 6 of the electric generator via a pipe 46. Note that said pipe 46 is equipped with a three-way connection 47 whose two outgoing channels are equipped valves 147, 247 for selectively directing the gas flow to the power generation equipment 6 of the electric generator and / or to the power generation equipment 4 of the powertrain. Note further that, in the embodiment shown, the main circuit for powering the power generation equipment 4 of the powertrain is not equipped with a compressor, unlike the secondary circuit because the circuit main and the pump 8a supplying the suction pipe 7a of the main circuit are able to provide pressures in accordance with the operating conditions of said power generation equipment 4.

FIG. 3 shows the routing of the gas through the secondary circuit when natural gas evaporated in the storage tank is incorporated in the secondary supply circuit of the power generation equipment 6. To do this , the system 3 comprises a pipe 71 opening in the upper part of the tank 2. A three-way connection 70 connects the pipe 71 opening in the upper part of the tank 2, to the secondary circuit via a pipe 48 provided with a valve 170, and a pipe 49, provided with a valve 270 and was part of a heating circuit whose function will be detailed later. The three-way connection 70 and the valves 170, 270 form a switchable three-way connection device.

The pipe 48 is, moreover, connected via a three-way connection 50 to a pipe 14. The three-way connection 50 connects the pipe 14 to a pipe 51 equipped with a valve 150 and forming part of the heating circuit and to the line 48 equipped with the valve 170. The three-way connection 50 and the valves 150 and 170 also form a switchable connection member. The pipe 14 is connected to the secondary circuit via a three-way connection 54 making it possible to connect the outlet of the sprayer 10b and the said pipe 14 to the inlet of the sprayer 31. The gas evaporated in the tank 2 is thus incorporated into the gas stream. leaving the forced evaporation plant 9b, before being led to the second sprayer 31, also having the function of controlling the temperature of the gas flow at the inlet of the phase separator 11b by spraying natural gas at liquefied state in the gas stream. Thus, the secondary supply circuit 10 comprises, in its upstream portion, an evaporated natural gas supply path, collected in the tank 2, and a forced evaporation path of natural gas. Such a gas supply path, evaporated in the tank, is particularly suitable when the liquefied natural gas is stored at ambient temperature and results in a consequent natural evaporation. Figures 4 and 5 illustrate the path for the natural gas supply of the burner 5. Figure 4 illustrates the forced vaporization path of the natural gas while Figure 5 illustrates the path of evaporated natural gas, collected in the tank 2. It should be noted that in both cases the burner supply circuit 20 bypasses the phase separator 11b so as to allow energy recovery of the heavy fraction of the natural gas. In FIG. 4, the burner supply circuit 5 comprises a common circuit portion with the secondary circuit. This common circuit portion allows the forced vaporization of the liquefied natural gas and includes the suction line 8b fed by the pump 8b, the forced spray installation 9b and, optionally, the sprayer 10b. Downstream of the forced evaporation plant 9b, the treatment and routing system 3 comprises a three-way connection 55 connecting the outlet of the forced evaporation plant 9b to the series of ducts 38, 39, 40. equipped with a valve 155 and leading to the phase separator 11b, and a pipe 56, equipped with a valve 255 for short-circuiting said phase separator 11b, in order to valorize, in the burner 5, the heavy fraction natural gas. Thus, the switchable connection member thus formed makes it possible to selectively convey the output of the forced evaporation plant 9b either to the phase separator 11b or to the burner 5. The line 56 conducts the gas flow, at the outlet of the the forced vaporization plant to a gas heater 57. The gas heater 57 is, for example, a gas / liquid or gas / gas heat exchanger. The gas heating apparatus 57 is here equipped with a recirculation loop 58. The gas heating apparatus 57 makes it possible to heat the gas phase upstream of said burner 5 at a set temperature, typically of the order 30 ° C. At the outlet of the gas heater 57, lines 68, 59 enable the gas to be led to the burner 5. In FIG. 5, the burner supply circuit 5 comprises another common circuit portion with the secondary circuit. This common circuit portion allows the collection of natural gas, evaporated in the tank 2. This common circuit portion comprises the pipe 71 opening in the upper part of the tank 2, the pipe 48 connected to the pipe 71 by the connection to three 70 and the line 14 connected to the pipe 71 by the three-way connection 50. The pipe 14 is, moreover, connected to a three-way connection 60 connecting the pipe 14 to the series of pipes 39, 40 leading to the phase separator 11b and to valves 143, 243 and to a line 56, equipped with a valve 160, and making it possible to short-circuit said phase separator 11b, in order to valorize, in the burner 5, the heavy fraction natural gas. Subsequently, as we have previously detailed in connection with FIG. 4, the pipe 56 conducts the gas flow to the gas heating apparatus 57 and then, at the outlet of the gas heating apparatus 57, pipes 68, 59 25 can lead the gas to the burner 5. Note that, if the natural gas path, evaporated in the tank 2, and the forced vaporization path of the natural gas are illustrated in two different figures in order to To facilitate understanding, it is quite possible to use both paths simultaneously to drive natural gas to the burner 5. The natural gas treatment and delivery system 3 is advantageously equipped with a control device for controlling the natural gas. a variable representative of the methane index of the liquefied natural gas conveyed. The methane number indicates the ability of the gas mixture to resist the unwanted knock phenomenon and is between 0 and 100. The methane number depends on the composition of the natural gas. The index of pure methane is 100. The index decreases when the proportion of heavier hydrocarbons such as propane and / or butane and / or pentane increases.

Such a control device for a variable representative of the methane index of the natural gas may include in particular one or more flow meters arranged downstream of one or both phase separators 11a, 11b, in the pipe 42 for example, to measure the gas flow rate of the light fraction of natural gas. This flow rate is representative of the methane index of the liquefied natural gas conveyed. Indeed, in steady state, constant pumping rate, this flow will tend to decrease when the tank 2 is empty and the concentration of heavy hydrocarbons increases. Alternatively or in addition, it is also possible to place a temperature sensor, for example in the pipe 48 for driving the evaporated gas, collected in the tank, to measure the temperature of the evaporated gas collected in the tank 2 Indeed, the higher the temperature of the evaporated gas, the more it has a significant proportion of heavy hydrocarbons, since we are approaching the end of the trip. In addition, alternatively or in addition, it is also possible to record the purge frequency of at least one of the condensate recovery containers 72a, 72b and / or to follow the evolution of the condensate level. at least one of the containers 72a, 72b. The control device also comprises a control unit able to receive and process the data collected by at least one of the sensors mentioned below. The control unit compares the representative variable (s) of the methane index with a threshold. According to this comparison, the control unit is able to generate an alarm or to automatically switch from an operating mode in which the natural gas supplies power generation equipment 4, 6 of the powertrain and / or of the electric generator in a mode of operation in which the heavy fraction of the natural gas is upgraded and conducted to the burner 5 of the power plant. In practice, when the representative variable of the methane index corresponds to a methane index of less than an index of about 80, the control unit generates an alarm or automatically switches to the recovery mode of the heavy fraction of the natural gas. In the embodiment providing such an automatic change of operating mode, the control device is able to transmit a setpoint signal to a plurality of valves 155, 255, 160, 143, 243 fitted to the three-way connections 55 and 60 of FIG. so as to bifurcate the gas flow to the burner 5 by short-circuiting said phase separator 11b. When the power generation equipment is a diesel-fueled mixed-gas combustion engine, in parallel with the transition to an operating mode in which the heavy fraction of the natural gas is recovered and sent to the burner 5, the heat engine 4 powertrain and / or that of the electric generator 6 switches to diesel mode in order to continue the propulsion of the ship and / or the generation of electricity. FIG. 6 illustrates the path of the natural gas when a method for heating the tank 2 is used. This process is implemented when the tank 2 is almost empty, the remainder of natural gas then being in gaseous form. in the tank 2. During the implementation of the heating method, the natural gas is collected in the lower part of the tank 2 by means of a pipe 52 opening 20 in the lower part of the tank 2. In the embodiment shown, the pipe 52 opening in the lower part of the tank 2 is connected to a switchable three-way connection member 53 for selectively connecting said pipe 52, or to a pipe 51 of the upstream portion of the heating circuit so as to allow A collection of gaseous flow in the lower part of the tank 2, or a circuit 61 for filling the tank 2 for conveying liquefied natural gas from a terrestrial tank to the tank 2. By elsewhere, the pipe 51 of the upstream portion of the heating circuit is connected, downstream, to a three-way connection 50. The valves 170, 150 can selectively connect either the pipe 51 of the upstream portion of the heating circuit, or the pipe 48 for driving the evaporated gas, collected in the tank 2, to the pipe 14.

The upstream portion of the heating circuit can thus be connected to the input of the compressors 16a, 16b via the pipes 39, 40 and 42 so as to conduct the gas collected at the bottom of the tank to the compressors. The temperature of the gas stream at the outlet of the compressors 16a, 16b, for carrying out the heating process of the tank 2, is, for example, of the order of 50 ° C. The circuit portion comprising the pipes 14, 39, 40 and 42 and at least one of the compressors 16a, 16b is thus common to the secondary gas supply circuit of a power generation equipment 4, 6 and heating circuit. Therefore, the design of the system 3 for treating and routing gas is optimized and at least one of the compressors 16a, 16b ensures both the preparation of a gas flow for the supply of a production equipment. energy 4, 6 and the implementation of a heating process of the tank 2. At the output of the compressors 16a, 16b, three-way connections 62, 63 connecting the output of the compressors 16a, 16b to the pipes 64, 65 equipped with valves 162, 163 and with ducts opening towards the secondary supply circuit and equipped with valves 262, 263. These ducts 64, 65 are connected via three-way connections 66, 67 to the duct 56 forming part of the circuit. supplying the burner 6 leading to the gas heating apparatus 57. Thus, for the heating of the tank 2, the gas flow passes both through the compressors 16a, 16b and through the apparatus of FIG. heating 57. Out of the device for heating the gas 57, the gas flow has, for example, a temperature of the order of 80 ° C. Furthermore, at the outlet of the gas heating apparatus 57, a duct 68 leads to a three-way connection 69 which makes it possible to discharge part of the flow, in excess, to the burner 5 via the duct 59 equipped with a valve 169 and return the other part of the gas stream to the tank 2 via a pipe 49 equipped with a valve 269 and forming a return section to the tank 2. It is thus understood that the pipe 56, the gas heater 57 as well as the duct 68 define a circuit portion which is common to the heating circuit of the tank 2 and the burner gas supply circuit 5. As a result, the pipes 64, 65 form sections connection for connecting the output of the compressors 16, 16b to the circuit portion which is common to the heating circuit of the tank 2 and the burner gas supply circuit 5. The pipe 49 forming a return section to the tank 2 is connected , by the three-way connection 70, to the pipe 71 opening in the upper part of the tank 2. Thus, depending on the position of the valves 170, 270, the pipe 71 opening in the upper part of the tank 2 can be used to the collection of the evaporated gas in the tank 2 when it is desired to supply a power generating equipment 4, 6 or the burner 5 with natural gas, or to inject hot gas when it is desired to heat the tank 2 Therefore, during the implementation of the heating process of the tank 2, hot gas is injected in the upper part of the tank 2 while the gas is extracted in the lower part of the tank 2. The hot gas having by nature This arrangement makes it possible to obtain a thermal stratification of the vessel 2, which increases the efficiency of the heating process of the vessel 2. In a manner known per se, as shown in FIG. Figure 7, loading lines / Unloading can be connected, by means of appropriate connectors, to a marine or port terminal for transferring a shipment of LNG to or from the tank 2. Figure 7 shows an example of a marine terminal with a liquefied natural gas supply station. 82, an underwater line 83 and an onshore facility 81. The liquefied natural gas supply station 82 is a fixed off-shore facility having a movable arm 84 and a tower 85 which supports the movable arm 84. The movable arm 84 insulated flexible pipe 80 which can connect to the loading lines. The swiveling arm 84 adapts to all ship sizes. A connection pipe (not shown) extends inside the tower 85. The liquefied natural gas supply station 82 allows the tank 1 of the vessel 1 to be filled from the shore installation 81. This comprises liquefied gas storage tanks 86 and connecting pipes 87 connected by the underwater pipe 83 to the liquefied natural gas supply station 82. The underwater pipe 83 allows the transfer of the liquefied gas between the station of supply of liquefied natural gas 82 and the onshore installation 81. In order to generate the pressure necessary for the transfer of the liquefied gas, pumps on board the ship 1 and / or pumps fitted to the shore installation 81 are used. / or pumps equipping the loading and unloading station 82. Although the invention has been described in connection with several particular embodiments, it is obvious that it is in no way limited and that it comprises all the technical equivalents of the means described and their combinations if they fall within the scope of the invention. In particular, if in the embodiments described above, the vessel has only one liquefied natural gas storage tank, it is also possible to connect the gas treatment and delivery system to a plurality of storage tanks. The storage tanks are, in this case, each equipped with suction lines fed by pumps and pipes opening into the upper part and the lower part of the tank, connected to the circuits of the treatment system as described above. . Note also that if the term connection member has been used above to describe the combination of a three-way connection with several valves equipping one or more incoming pipes or one or more outgoing pipes, this term extends to all the technical equivalents for connecting two incoming pipes to an outgoing pipe or an incoming pipe to two outgoing pipes, and equipped with means making it possible, according to the circumstances, to make a selection to favor either a stream coming from one of the two incoming pipes is a flow towards one of the two outgoing pipes or to distribute either an incoming flow to two outgoing flows or two incoming flows to an outgoing flow. The use of the verb "to include", "to understand" or "to include" and of its conjugate forms does not exclude the presence of other elements or other steps than those set forth in a claim. The use of the indefinite article "a" or "an" for an element or a step does not exclude, unless otherwise stated, the presence of a plurality of such elements or steps.

In the claims, any reference sign in parentheses can not be interpreted as a limitation of the claim.

Claims (13)

REVENDICATIONS1. Natural gas processing and conveying system comprising: a power supply circuit of a power generation equipment selected from a heat engine, a fuel cell, or a gas turbine, for conveying natural gas from a tank (2) for storing liquefied natural gas to said power generation equipment (4, 6), said supply circuit comprising an upstream portion connected to the tank (2) and a downstream portion connected to the power generation equipment (4, 6); a burner supply circuit for conveying natural gas from the tank (2) to the burner (5) having an upstream portion connected to the tank (2) and a downstream portion connected to the burner (5); a heating circuit of the tank (2) capable of collecting a gaseous flow in the lower part of the tank (2) and injecting it into the upper part of the tank (2), said heating circuit comprising an upstream portion connected to a pipe (52) opening in the lower part of the tank (2) and a downstream portion connected to a pipe (71) opening in the upper part of the tank (2); wherein: the power supply circuit of the power generation equipment and the heating circuit comprise a common circuit portion which includes a compressor (16a, 16b) having an input and an output and for increasing the pressure and the temperature of a gaseous flow, said common portion being delimited, upstream, by a first switchable first three-way connecting member (50, 150, 170) for selectively connecting the upstream portion of the feed circuit of the energy generating equipment or the upstream portion of the heating circuit at the inlet of the compressor (16a, 16b) and, downstream, by a second switchable three-way connecting member (62, 162, 262; , 263) for selectively connecting the compressor output to the downstream portion of the power supply circuit of the power generation equipment or to the downstream portion of the heating circuit; the downstream portion of the heating circuit comprising a third three-way connection member (69) for connecting said downstream portion of the heating circuit to the downstream portion of the burner supply circuit (5) so as to evacuate a portion of the gas flow fed into the heating circuit to the burner (5). 2. System according to claim 1, wherein the downstream portion of the heating circuit comprises a connection section (64, 65) at the outlet of the compressor and a return section (49) towards the tank (2) and in which the downstream portion of the heating circuit and the burner feed circuit comprise a common portion which comprises a gas heater (57) having an inlet and an outlet, said common portion being delimited upstream by a fourth connecting member three-way switchable circuit (66, 67, 160, 162, 163) for selectively connecting the upstream portion of the burner supply circuit (5) or the connection section (64, 65) to the output of the compressor (16a, 16b) of the heating circuit at the inlet of the heating apparatus (57) and, downstream, by the third three-way connection member (69, 169, 269) which makes it possible to connect the output of the gas heater (57) to the portio n downstream of the burner supply circuit and the return section (49) to the heating circuit tank. 3. System according to claim 1 or 2, comprising a switchable three-way connecting member (70, 170, 270) for selectively connecting said pipe (71) opening at the top of the tank, on the one hand, to the downstream portion of the heating circuit so as to allow an injection of the gaseous flow in the upper part of the tank (2) or, on the other hand, to the upstream portion of the supply circuit of the power generation equipment ( 4, 6) and / or the upstream portion of the burner supply circuit to allow collection of the gas, evaporated in the tank (2). 4. System according to any one of claims 1 to 3, comprising a filling circuit (61) of the tank and a switchable three-way connection member (53) for selectively connecting said pipe (52) opening at the bottom of the tank (2), on the one hand, to the upstream portion of the heating circuit so as to allow a gas flow collection in the lower part of the tank (2) or, on the other hand, to the filling circuit of tank. 5. System according to any one of claims 1 to 4, wherein the supply circuit of the power generation equipment comprises a phase separator (11a) connected, downstream, on the one hand, to a return duct (12a) for returning, in the form of condensate, to the tank (2), a heavy fraction of the natural gas comprising the hydrocarbons having the longest carbon chain and, on the other hand, to a duct (42). ) connected to the inlet of the compressor (4) to conduct a light fraction of the natural gas comprising the hydrocarbons having the shortest carbon chain. 6. System according to claim 5, and wherein the burner supply circuit (5) bypasses said phase separator (11a). 7. System according to any one of claims 1 to 6, wherein the compressor (16a, 16b) is a multi-stage compressor. 8. System according to any one of claims 1 to 7, comprising a device for protecting the compressor, said protection device comprising, a recirculation loop (44) equipped with a valve (18a, 18b) for returning upstream. compressor (16a, 16b) a gas stream collected downstream of said compressor (16a, 16b). 9. System according to any one of claims 1 to 8, wherein the circuit portion common to the power supply circuit of the power generation equipment (4, 6) and to the heating circuit comprises a plurality of compressors ( 16a, 16b) arranged in parallel. A vessel having a liquefied gas storage tank (2), a power generating equipment (4, 6) selected from a heat engine, a fuel cell and a gas turbine (4, 6), an installation energy production system with a burner (5) and a natural gas treatment and delivery system according to any one of claims 1 to 9. 11. Ship according to claim 10, wherein the power generation equipment (4, 6) is intended to propel the ship. A method of filling a tank of a vessel (1) according to claim 11, wherein a fluid is conveyed through insulated pipelines (80) from a floating or land storage facility (81) to the vessel ( 2) of the ship (1). 13. Transfer system for a fluid, the system comprising a ship (1) according to claim 11, insulated pipes (80) arranged to connect the vessel (2) installed in the hull of the vessel to a floating storage facility or earth (81) and a pump for driving a flow of fluid through the insulated pipelines from the floating or land storage facility to the vessel vessel.