DEVICE AND METHOD FOR PRE-COOLING A TARGET FLUID TO BE LIQUEFYING

Abstract

TITLE: DEVICE AND METHOD FOR PRE-COOLING A TARGET FLUID TO BE LIQUEFYING The device (100) for pre-cooling a target fluid comprises: - an inlet (105) for a first fluid in the liquid phase, - a means (155) for compressing the first fluid in the liquid phase, - a heat exchanger (115) between the first compressed fluid and a pre-cooling fluid to cool the pre-cooling fluid, - an expander (120) for the first fluid downstream of the heat exchanger, - a compressor (125) for the pre-cooling fluid, - a converter (130) of mechanical expansion energy, obtained by the operation of the expander, into mechanical compression energy supplied to the compressor, - a means (135, 205) for expanding the pre-cooling fluid at the outlet of the heat exchanger and - a means (140) for pre-cooling between the expanded pre-cooling fluid and a target fluid to cool the target fluid. Figure for abstract: Figure 1

Description

Title of the invention: DEVICE AND METHOD FOR PRE-COOLING A TARGET FLUID TO BE LIQUEFYING Technical field of the invention

[0001] The present invention relates to a device for pre-cooling a target fluid to be liquefied and a method for pre-cooling a target fluid to be liquefied. It applies, in particular, to the field of fluid liquefaction. State of the art

[0002] The approaches described in this section are approaches that could be pursued, but not necessarily approaches that have been conceived or pursued previously. Therefore, unless otherwise indicated, it should not be assumed that any of the approaches described in this section constitute prior art solely because of its inclusion in this section.

[0003] Liquefaction processes are divided into three major temperature technological blocks: compression, pre-cooling and refrigeration.

[0004] For example, for a flow of dihydrogen (hereinafter "hydrogen"), the precooling aims to lower the inlet temperatures located between 273 K (-0.15 °C) and 320 K (46.85 °C) of the hydrogen fluid of interest and of the fluid used for refrigeration in the following block, to a temperature located between 78 K (-195.15 °C) and 120 K (-153.15 °C).

[0005] The liquefaction of a fluid, and in particular of hydrogen, is an energy and economic intensive process.

[0006] Hydrogen liquefaction is characterized by its pre-cooling and cooling cycles, also called "pre-cooling" and "cooling". Many liquefaction solutions have been developed, based on open, closed, Joule-Thomson, Brayton or Claude cycles for their cooling and / or pre-cooling.

[0007] For cooling, the refrigerants encountered in the literature are restricted due to the extremely low liquefaction temperature of hydrogen (approx. 20K or -253.15°C at 1 atm). These include helium, hydrogen, neon or a mixture combining at least two of the above elements.

[0008] For pre-cooling, nitrogen, methane, or a mix of C1 to C5 hydrocarbons and nitrogen are conventionally used in Brayton or Claude cycles.

[0009] The use of the cold of liquefied natural gas (or "LNG") has been applied to the liquefaction of hydrogen in that it allows the reduction of energy consumption of pre-cooling. Three main families of solutions can be distinguished.

[0010] The first family of solutions covers processes using the cold of LNG in an open cycle of hydrogen compressed at cryogenic temperature. Compression at cryogenic temperature or cryo-compression refers to a particular compression where the fluid enters the compressor at a sub-ambient temperature (< -40°C).

[0011] Thus, since 1990, the recovery of cold from LNG has been applied to an open hydrogen cooling cycle, and replaces the open liquid nitrogen circuit of the pre-cooling with an open circuit of LNG at low pressure and at -158°C (115 K). Cryo-compression of hydrogen at -100°C (173 K) cooled by LNG has also been introduced, allowing a reduction in specific energy consumption. This cooling cycle can be optimized with intermediate Brayton expansions in the hydrogen circuit. The refrigerant hydrogen is also compressed to a cryogenic temperature between -140°C (133 K) and -158°C (115 K) thanks to the cold of the high-pressure LNG. In some cases, the hydrogen is also cooled with LNG between the two compression stages. LNG consumption varies between 22.9 kgGNL / kgLH2 and 37.1 kgGNL / kgLH2.In recent approaches, a liquid nitrogen production cycle is integrated and, in this process, gaseous nitrogen is compressed cold (approximately to LNG temperature) and then cooled by LNG before being expanded, thus producing two-phase nitrogen. The latter pre-cools the hydrogen to -193°C (80 K), allowing a lower temperature to be reached than simple pre-cooling with LNG.

[0012] The second family of solutions brings together solutions integrating the frigories of LNG into a closed hydrogen cycle whose cooling fluid is cryo-compressed to the bubble temperature of LNG. A process for liquefying hydrogen produced by a methane steam reforming unit, itself supplied with LNG, is thus known. The regasification of LNG is carried out in a closed Claude cycle with pre-cooling with LN2 (i.e. liquid nitrogen) for pre-cooling the feed and the cooling refrigerant. LNG is also supplied to carry out cryogenic compression of the refrigerant. The regasification of LNG to provide frigories is carried out simply using two heat exchangers. One between the LNG and the hydrogen flow to be liquefied, the other between the LNG and the hydrogen refrigerant. The liquid nitrogen supply was maintained to bring the fluids down to -193°C (80 K).There is also a known solution using a hydrogen liquefier with the same concepts, but the two stages of hydrogen compression in the cooling circuit are cryogenic compressions. Some other approaches implement cryogenic compression of the two stages of hydrogen refrigeration but do not include LN2 for its pre-cooling. Some others . approaches complicate the process with a closed nitrogen cycle from Claude which is also refrigerated by LNG for its compression.

[0013] A final family of solutions can also be cited vaporizing LNG in a hydrogen liquefaction cycle without performing cryogenic compression of its cooling refrigerant. Such a liquefaction cycle comprises, for example, an open hydrogen cooling cycle and a nitrogen Brayton cycle for pre-cooling, both cooled by LNG. Other approaches limit the use of LNG to pre-cooling the hydrogen supply but have respectively integrated the latter into a helium Brayton cooling cycle and refrigerant mix Brayton cooling cycles including at least two components from among helium, neon and hydrogen.

[0014] In addition, inspired by the LNG industry, the recycling of frigories produced on a methane terminal during the regasification of LNG before its injection into the network is well known to those skilled in the art. Thus, families of solutions such as ORCs (for "Organic Rankine Cycle") whose objective is to produce electricity or industrial synergies with air separation plants (abbreviated "ASU" for Air Separation Unit) for example have been extensively developed.

[0015] All the solutions described above are, however, energetically and economically inefficient and difficult to implement near a liquefied natural gas regasification system. Statement of the invention

[0016] The present invention aims to remedy all or part of these drawbacks.

[0017] To this end, according to a first aspect, the present invention relates to a device for pre-cooling a target fluid, which comprises: - an inlet for a first fluid in the liquid phase, - a means for compressing the first fluid in the liquid phase, - a heat exchanger between the first compressed fluid and a pre-cooling fluid for cooling the pre-cooling fluid, - an expander for the first fluid downstream of the heat exchanger, - a compressor for the pre-cooling fluid, - a converter of mechanical expansion energy, obtained by the operation of the expander, into mechanical compression energy supplied to the compressor, - a means for expanding the pre-cooling fluid at the outlet of the heat exchanger and - a pre-cooling means between the expanded pre-cooling fluid and a target fluid for cooling the target fluid.

[0018] The present invention makes it possible to extract from the first fluid, for example LNG, both frigories and mechanical energy production in order to supply a pre-cooling circuit in the liquefaction cycle of the target fluid and to reduce the energy consumption of the latter. This also makes it possible to spatially separate the regasification of the LNG and the liquefaction of the hydrogen.

[0019] Thus, the use of a converter of mechanical energy (such as a turbocharger) from the expansion valve into mechanical energy from the compression of the compressor allows: - to carry out pre-cooling of target fluid with, in variants, for only energy consumption a means of overpressurizing the first fluid, - to achieve a pre-cooling temperature of the target fluid lower than the LNG temperature thanks to the expansion of the pre-cooling fluid, - to separate the gas regasification and target fluid liquefaction circuits and - to be robust in the face of variations in composition and temperature of the first fluid.

[0020] In optional embodiments, the first fluid is methane-rich gas, such as natural gas or biogas.

[0021] In optional embodiments, the target fluid is dihydrogen.

[0022] In optional embodiments, the device which is the subject of the present invention comprises a means for vaporizing the first fluid in liquid phase downstream of the first fluid regulator and / or downstream of the inlet for the first fluid.

[0023] These embodiments make it possible to obtain natural gas in the vapor phase.

[0024] In optional embodiments, the device which is the subject of the present invention comprises at least one additional heat exchanger, between the first fluid and the pre-cooling fluid coming from the pre-cooling means, the pre-cooling fluid at the outlet of an additional heat exchanger being supplied to the compressor. In optional embodiments, at least two heat exchangers are combined.

[0025] In optional embodiments, the device which is the subject of the present invention comprises a turbocharger configured to expand the pre-cooling fluid upstream of the pre-cooling means and to compress the pre-cooling fluid upstream of a heat exchanger.

[0026] The implementation of such a turbocharger is particularly suitable, although optional, when the pre-cooling fluid is nitrogen.

[0027] In optional embodiments, the device which is the subject of the present invention comprises a heat exchanger configured to heat the first fluid at the outlet of the heat exchanger and to supply the first heated fluid to the expansion valve.

[0028] These embodiments make it possible to optimize the expansion of the first fluid and therefore the quantity of compression energy obtained as a result.

[0029] In optional embodiments, the device which is the subject of the present invention comprises a compression block for the target fluid and a circuit for circulating a heat transfer fluid between the heat exchanger and the compression block for the target fluid.

[0030] These embodiments make it possible to use the frigories of the first fluid to cool a heat transfer fluid used in a compression block of the target fluid.

[0031] According to a second aspect, the present invention aims at a method of pre-cooling a target fluid, which comprises: - an entry step for a first fluid in liquid phase, - a step of compression of the first fluid in liquid phase, - a heat exchange step between the first compressed fluid and a pre-cooling fluid to cool the pre-cooling fluid, - a stage of expansion of the first fluid downstream of the heat exchange stage, - a step of compression of the pre-cooling fluid, supplied with mechanical energy by a step of conversion of the mechanical expansion energy obtained during the expansion step, - a stage of expansion of the pre-cooling fluid at the outlet of the heat exchange stage and - a pre-cooling step between the expanded pre-cooling fluid and a target fluid to cool the target fluid. Brief description of the figures

[0032] Other advantages, aims and particular characteristics of the invention will emerge from the following non-limiting description of at least one particular embodiment of the device and method which are the subject of the present invention, with reference to the appended drawings, in which:

[0033] [Fig. 1] schematically represents a first particular embodiment of the device which is the subject of the present invention,

[0034] [Fig.2] schematically represents a second particular embodiment of the device which is the subject of the present invention,

[0035] [Fig.3] schematically represents a third particular embodiment of the device which is the subject of the present invention,

[0036] [Fig.4] schematically represents a fourth particular embodiment of the device which is the subject of the present invention,

[0037] [Fig.5] schematically represents a fifth particular embodiment of the device which is the subject of the present invention,

[0038] [Fig.6] schematically represents a sixth particular embodiment of the device which is the subject of the present invention and

[0039] [Fig.7] represents, schematically and in the form of a flowchart, a succession of particular steps of the method which is the subject of the present invention. Description of the embodiments

[0040] The present description is given without limitation, each characteristic of an embodiment being able to be combined with any other characteristic of any other embodiment in an advantageous manner.

[0041] It should be noted from now on that the figures are not to scale.

[0042] As understood from reading this description, various concepts The inventive methods may be implemented by one or more methods or devices described below, several examples of which are provided herein. The actions or steps performed in carrying out the method or device may be ordered in any suitable manner. Accordingly, it is possible to construct embodiments in which the actions or steps are performed in a different order than illustrated, which may include performing certain acts simultaneously, even if they are shown as sequential acts in the illustrated embodiments.

[0043] As used herein in the description and in the claims, "or" is to be understood as having the same meaning as "and / or". For example, when separating elements in a list, "or" or "and / or" is to be interpreted as being inclusive, i.e., the inclusion of at least one, but also more than one, number or list of elements, and, optionally, additional elements not listed. Only terms clearly indicating the contrary, such as "only one of" or "exactly one of", or, when used in the claims, "consisting of", refer to the inclusion of only one element of a number or list of elements. In general, the term "or" as used herein should only be construed as indicating exclusive alternatives (i.e., "either but not both") when preceded by terms of exclusivity, such as "either," "one of," "only one of," or "exactly one of."

[0044] As used in this specification and in the claims, the expression "at least one", with reference to a list of one or more elements, is to be understood to mean at least one element selected from one or more elements in the list of elements, but not necessarily including at least one of each element specifically listed in the list of elements and not excluding every combination of elements in the list of elements. This definition also allows for the optional presence of elements other than the specifically identified elements in the list of elements to which the expression "at least one" refers, whether or not related to those specifically identified elements. Thus, by way of example not limiting, "at least one of A and B" (or, equivalently, "at least one of A or B", or, equivalently, "at least one of A and / or B") may refer, in one embodiment, to at least one, optionally including more than one, A, without B present (and optionally including elements other than B); in another embodiment, to at least one, optionally including more than one, B, without A present (and optionally including elements other than A); in yet another embodiment, to at least one, optionally including more than one, A, and at least one, optionally including more than one, B (and optionally including other elements); etc.

[0045] In the claims, as well as in the description below, all transitional expressions such as "comprising", "including", "carrying", "having", "containing", "involving", "holding", "composed of", and the like, are to be understood as being open, i.e., as meaning including but not limited to. Only the transitional expressions "consisting of" and "consisting essentially of" are to be understood as closed or semi-closed transitional expressions, respectively.

[0046] In the present description, a gas or fluid of a given compound is understood as a gas or fluid comprising a majority of this given compound. By majority, we mean at least 50% and preferably at least 60%, 70%, 80% or 90%.

[0047] The target fluid designates any gas or liquid to be cooled, subcooled or liquefied suitable for the implementation of the present invention.

[0048] [Fig. 1], which is not to scale, shows a schematic view of an embodiment of the device 100 which is the subject of the present invention. This device 100 for pre-cooling a target fluid comprises: - an inlet 105 for a first fluid in liquid phase, - a means 155 for compressing the first fluid in liquid phase, - a heat exchanger 115 between the first compressed fluid and a pre-cooling fluid to cool the pre-cooling fluid, - a pressure regulator 120 of the first fluid downstream of the heat exchanger, - a 125 compressor of the pre-cooling fluid, - a converter 130 of mechanical expansion energy, obtained by the implementation of the expander, into mechanical compression energy supplied to the compressor, - a means 135 for expanding the pre-cooling fluid at the outlet of the heat exchanger and - a means 140 for pre-cooling between the expanded pre-cooling fluid and a target fluid for cooling the target fluid.

[0049] The inlet 105 for the first fluid is, for example, a pipe adapted to the nature of the first fluid considered. The particular dimensions of this pipe are not limiting and are adapted to the use case.

[0050] The first fluid is here, for example, a methane-rich gas, such as liquefied natural gas. By "methane-rich gas" is meant a gas whose molar composition comprises a relative or absolute majority of methane. In variants, a methane-rich gas comprises at least 50%, 60%, 70%, 90% or 95% methane.

[0051] This first fluid is preferably intended to be regasified, that is to say to adopt a vapor phase at a temperature adapted to its use case by heating.

[0052] Such heating may partially take place in the heat exchanger 115.

[0053] The compression means 155 may be a compressor of any known type suitable for the use case, such as a pump for example. At the outlet of this compression means 155, the first fluid may have a pressure of 80 bara.

[0054] The heat exchanger 115 may be of any known type of heat exchanger adapted to the use case of implementing the device 100. For example, this heat exchanger 115 is a multi-flow exchanger.

[0055] This heat exchanger 115 admits, as a cold source, the first fluid in liquid phase and, as a hot source, the pre-cooling fluid.

[0056] The pre-cooling fluid is, for example: - a refrigerant mixture mainly comprising methane, in liquid or gaseous phase, - dihydrogen, - nitrogen or - carbon dioxide.

[0057] At the outlet of this heat exchanger 115, the first partially heated fluid is supplied to an expansion valve 120.

[0058] At the outlet of this heat exchanger 115, the pre-cooling fluid has a temperature comparable to the temperature of the first fluid.

[0059] At the outlet of this heat exchanger 115, the pre-cooling fluid has, for example, a temperature approximately equal to 121 K (-152°C).

[0060] The regulator 120 may be of any known type of regulator adapted to the use case of implementing the device 100.

[0061] For example, this expander 120 is the expansion segment of a turbocharger.

[0062] At the output of the device, 100, 200, 300, 400, 500, 600, as shown in figures 1, 2, 3, 4, 5 and 6, the first fluid has for example a temperature of the order of 275 K (2°C).

[0063] In particular embodiments, such as shown in figures 1, 2, 3, 4, 5 and 6, the device, 100, 200, 300, 400, 500, 600, object of the present invention comprises a heat exchanger 160 configured to heat the first fluid upstream of the inlet of the first fluid into the expansion valve 120.

[0064] The presence of such an exchanger 160 is not obligatory, but its presence substantially improves the performance of the device 100 because, the hotter the flow of first fluid entering the expander 120, the higher the compression performance of the compressor 125.

[0065] At the outlet of the heat exchanger 160, the first fluid has, for example, a temperature of 275 K (2°C). The objective of this heat exchanger 160 is to vaporize the first fluid to obtain as much energy as possible in the expansion valve 120.

[0066] In particular embodiments, such as that shown in [Fig.6], the heat exchange carried out in the heat exchanger 160 is used to cool the target fluid.

[0067] In such embodiments, the device 600 comprises a compression block 101 of the target fluid and a circuit 605 for circulating a heat transfer fluid between the heat exchanger 160 and the compression block 101 of the target fluid.

[0068] Downstream of the regulator 120, the first fluid is in the vapor phase or at least partially in the liquid phase.

[0069] In particular embodiments, such as represented in figures 1, 2, 3, 4, 5 and 6, the device, 100, 200, 300, 400, 500, 600, object of the present invention comprises a means (referenced 145 in [Fig.l]) for vaporizing the first fluid in liquid phase downstream of the expander 120 of the first fluid and / or downstream of the inlet 105 for the first fluid.

[0070] The first fluid leaves the device 100 through an outlet 166 for the first fluid in vapor phase. For example, the first fluid leaving the device 100 has a temperature of 275 K (2°C) and a pressure of 30 bara.

[0071] In variants, the entire flow of first liquid fluid passes through the heat exchanger 115.

[0072] In other variants, such as that shown in [Fig.l] and implicitly in figures 2, 3, 4, 5 and 6, the device 100 comprises a bypass 165 configured to receive a portion of the flow of first liquid fluid not passing through the heat exchanger 115 or, more generally, not interacting with the pre-cooling fluid.

[0073] In such variants, the flow of first fluid passing through the heat exchanger 115 and the flow of first fluid passing through the bypass 165 can join. upstream of the vaporization means 145. In other variants, at least one of these flows is associated with a specific vaporization means 145.

[0074] The pre-cooling fluid flow is preferably designed to operate in a closed cycle. In variants, an open cycle can be implemented.

[0075] The flow of pre-cooling fluid, at the outlet of the heat exchanger 115, is supplied to an expansion means 135.

[0076] This expansion means 135 can be of any type adapted to the use case of the device 100. For example, this expansion means 135 is a Joule-Thomson valve.

[0077] In variants, such as that shown in [Fig.2], the expansion means 205 is a pressure reducer.

[0078] In other variants, such as those shown in Figures 3 and 5, the expansion means 305 corresponds to an expansion part of a turbocharger.

[0079] At the outlet of the expansion means 135, the flow of pre-cooling fluid has a temperature lower than the temperature of the first fluid in the heat exchanger 115. This expanded pre-cooling fluid is supplied to the pre-cooling means 140.

[0080] At the outlet of the expansion means 135, the flow of pre-cooling fluid has, for example, a temperature of 113.5 K (-159.5°C).

[0081] The pre-cooling means 140 may be any type of known heat exchanger suitable for the use case of implementing the device 100. For example, this heat exchanger 140 is a finned exchanger.

[0082] The pre-cooling means 140 admits, as a cold source, the expanded pre-cooling fluid and, as a hot source, the target fluid.

[0083] At the outlet of the pre-cooling means 140, the pre-cooling fluid is, directly or indirectly, supplied to a compressor 125.

[0084] At the outlet of the pre-cooling means 140, the target fluid has, for example, a temperature of 115.6 K (-157.5°C).

[0085] The compressor 125 may be of any known type of compressor suitable for the use case of implementing the device 100.

[0086] For example, this compressor 125 corresponds to a compression part of a turbocharger.

[0087] The compressor 125 is operated by recovering the energy produced by the expansion of the flow of the first fluid. Such recovery is carried out by the energy converter 130.

[0088] At the outlet of the compressor 125, the flow of refrigerant fluid has, for example, a pressure of approximately 16.5 bara.

[0089] The energy converter 130 is, for example, a shaft implemented in a turbocharger for expanding the first fluid and compressing the pre-cooling fluid.

[0090] The energy converter 130 may also consist of two parts: - a conversion of mechanical energy from expansion into electrical energy comprising a generator on a turbine shaft and - a conversion of electrical energy into mechanical compression energy by a motor, each conversion then being carried out by a separate device.

[0091] In variants, such as those shown in figures 1, 2 and 6, the pre-cooling fluid from the pre-cooling means 140 is supplied to the heat exchanger 115, here merged with an additional heat exchanger 150, and the pre-cooling fluid subsequently from this heat exchanger 115 is supplied to the compressor 125.

[0092] In such variants, the pre-cooling fluid makes two passages in the heat exchanger 115: a first downstream of compression and a second downstream of the pre-cooling means 140.

[0093] In variants, such as that shown in [Fig.3]: - the pre-cooling fluid from the pre-cooling means 140 is supplied to the heat exchanger 115, here combined with an additional heat exchanger 150, - the pre-cooling fluid subsequently coming from this heat exchanger 115 is supplied to the compressor 125 and - the pre-cooling fluid subsequently coming from this heat exchanger 115 is supplied to a compressor 310 then reinjected into the heat exchanger 115.

[0094] In particular embodiments, the device comprises a turbocharger 306 configured to expand the pre-cooling fluid upstream of the pre-cooling means and to compress the pre-cooling fluid upstream of a heat exchanger 150.

[0095] The compressor 310 is, for example, a compression part of the turbocharger 306.

[0096] In variants, such as that shown in [Fig.4], the pre-cooling fluid from the pre-cooling means 140 is supplied to an additional heat exchanger 150, and the pre-cooling fluid subsequently from this additional heat exchanger 150 is supplied to the compressor 125 before being supplied to the heat exchanger 115.

[0097] In variants, such as that represented in [Fig.5], the principle represented in [Fig.4] is extended to a succession of additional heat exchangers, 150 and 151, of variable number and here limited to two.

[0098] In these variants, the pre-cooling fluid from the pre-cooling means 140 is supplied to a first additional heat exchanger 150. The pre-cooling fluid subsequently from this additional heat exchanger 150 is supplied to the compressor 125 before being supplied to a second additional heat exchanger 151. The pre-cooling fluid subsequently from this additional heat exchanger 151 is supplied to a compressor 310, such as the compression part of a turbocharger, before being supplied to the heat exchanger 115.

[0099] The target fluid is preferably dihydrogen.

[0100] This target fluid is, for example, injected into the pre-cooling means 140 via a target fluid inlet 110.

[0101] Such an inlet 110 corresponds, for example, to a pipe adapted to the nature of the target fluid considered. The particular dimensions of this pipe are not limiting and are adapted to the use case.

[0102] The target fluid may pass through, for example, a complex liquefaction system.

[0103] Such a system comprises, for example: - a compression block 101 of the target fluid, - a device 102 for cooling the target fluid and - a circulation circuit 103 between the compression block 101, the cooling device 102 and the pre-cooling means 140, configured to provide, to the pre-cooling means 140: - a target fluid flow from the target fluid inlet 110, - a low-pressure target fluid flow 104 from the cooling device 102, - a medium-pressure target fluid flow 106 from the cooling device 102 and - a flow 107 of high-pressure target fluid from the compression block 101.

[0104] Such liquefaction systems are also well known in the field of gas liquefaction.

[0105] In particular embodiments, such as those shown in figures 1, 2, 3, 4, 5 and 6, the device, 100, 200, 300, 400, 500, 600, object of the present invention comprises a compressor 108 of the flow of first fluid coming from the inlet 105 of the first fluid.

[0106] Such a compressor 108 may be of any known type and adapted to the use case, such as a pump for example. For example, at the outlet of the compressor 108, the first fluid may have a pressure of 30 bara.

[0107] As understood, in certain variants, the device 100 implements: - an LNG regasification circuit, which aims to exchange part of the frigories with a pre-cooling fluid and to supply an expansion turbine before being regasified at a temperature of 275 K (2°C), - a pre-cooling fluid circuit, operating in a closed loop between 303 K (30°C) and 113.6 K (-159.5°C), the main purpose of which is to refrigerate a flow of dihydrogen and the cooling flow of hydrogen from 298 K (25°C) to 115.6 K (-157.5°C) and - a hydrogen pre-cooling cycle, comprising a multi-flow heat exchanger allowing an exchange of cold between the refrigerant flow, the hydrogen supply flow and the hydrogen cooling flow.

[0108] Such variants allow the use of a turbocharger on the regasification circuit and the reuse of the recovered mechanical energy for the compression of an intermediate fluid used for the pre-cooling of the hydrogen.

[0109] Table 1 below presents proposed operating value ranges for the device 100 presented in [Fig.l] for a device 100 using LNG as the first fluid and hydrogen as the target fluid.

[0110] [Tables 1] Parameters Lower limit Upper limit LNG high pressure (bara), at outlet 155 40 200 LNG flow rate (tons per day) at inlet 105 145 256 Pre-cooling fluid high pressure (bara), at compressor outlet 125 6.8 25.3 Pre-cooling fluid low pressure (bara), at expander outlet 135 1 2 Pre-cooling fluid flow rate (tons per day) 31.5 40 Pre-cooling fluid temperature at heat exchanger outlet 115 (K / °C) 111 / -162 130 / -143 Hydrogen pre-cooling temperature (K / °C) 115.6 / -157.5 120 / -153 LNG / pre-cooling fluid flow ratio pre-cooling 4.39 7.75 LNG / liquefied hydrogen flow ratio 14.5 25.6

[0111] The interests of the cycle described are multiple: - carry out pre-cooling of the hydrogen whose only energy consumption corresponds to the initial additional compression of the LNG, - achieve a pre-cooling temperature of the hydrogen lower than the temperature of the LNG thanks to the expansion of the pre-cooling fluid, - separate the gas regasification and hydrogen liquefaction circuits and - be robust in the face of variations in the composition and temperature of the LNG.

[0112] In variants not shown, the first fluid at the inlet 105 of the device 100 has a so-called “low” pressure. Such a variant is for example implemented by the reinjection of a methane-rich gas into a lower pressure distribution network. Such variants make it possible to obtain greater energy recovery at the level of the expander 120, thanks to a higher expansion rate compared to the operating conditions of the device 100 as presented in Table 1. The result is a reduction in the LNG required for the operation of the refrigeration cycle. These variants can be implemented for Bio-LNG distribution networks, which are at a pressure of 7 bara. The LNG / LH2 ratio is between 9.5 and 12 in this case and the cooling temperature is unchanged.

[0113] In variants, it is possible to cool the methane in the pre-cooling fluid circulation circuit without causing a phase change. In this case, the temperature of the pre-cooling fluid will be higher resulting in pre-cooling of the hydrogen to 121 K (-152°C). The result is a less efficient pre-cooling cycle but which requires a lower use of LNG. The LNG / LH2 ratio is, for example, between 4 and 9.

[0114] In variants, both without phase change and at low pressure, the LNG / LH2 ratio is between 3.5 and 8 and the pre-cooling temperature is 121 K(-152°C).

[0115] In addition to the structural differences of the variants shown in Figures 2 to 6, the functional differences of these variants are shown below.

[0116] In the variant of the device 200 shown in [Fig.2], it is possible to use a pre-cooling fluid having the possibility of reaching lower temperatures than methane. An example is the use of nitrogen in the refrigerant loop. Nitrogen makes it possible to reach pre-cooling temperatures below 100 K (173°C) with the counterpart of the need to increase the flow rate of LNG required. The LNG / LH2 ratios are in this configuration between 18 and 33 depending on the desired pre-cooling temperature.

[0117] In the variant of the device 300 shown in [Fig.3], it is possible to implement a pre-cooling fluid having the possibility of reaching lower temperatures than methane. An example is the use of nitrogen in the loop refrigeration. In this configuration, a compressor and a turbine (or a turbocharger) are added to the device 300. The nitrogen is expanded in the turbine, or the expansion part of a turbocharger, which drives an additional nitrogen compressor. This configuration makes it possible to achieve higher compression pressures or to perform pre-cooling using a lower LNG flow rate. This configuration makes it possible to achieve pre-cooling temperatures below 100 K (-173°C) with LNG / LH2 ratios between 10 and 14 depending on the desired pre-cooling temperature.

[0118] The variants of the device, 400 and 500, shown in [Fig.4] and 5, aim to reduce the construction complexity of the heat exchanger 115 by using several heat exchangers, 115, 150 and 151, instead of a single heat exchanger 115. The advantage of this configuration is to have the possibility of using bi-flow exchangers and not using a multi-flow exchanger. In this configuration, an additional heat exchanger 150 is used before each compression step to cool the pre-cooling fluid and improve the compression efficiency. This configuration ([Fig.5]) has two additional heat exchangers compared to the device shown in [Fig.1] and one additional exchanger compared to the variant shown in [Fig.4].

[0119] In the variant of the device 600 shown in [Fig.6], the additional recovery of the remaining cold from the LNG after the exchanges with the pre-cooling fluid and before the expansion step is carried out in the heat exchanger 160. Indeed, the LNG leaving the exchanges has a temperature between 200 K (-73°C) and 220 K (-53°C), allowing subsequent recovery of the frigories. This recovery is carried out with the use of a closed cycle containing a second heat transfer fluid, which is cooled by exchange against the LNG and then used as heat transfer fluid for cooling the hydrogen and the compression block.

[0120] In [Fig.7], we observe a succession of particular steps of the method 700 which is the subject of the present invention. This method 700 for pre-cooling a target fluid comprises: - a step 705 of entry of a first fluid in liquid phase, - a step 706 of compression of the first fluid in liquid phase, - a step 715 of heat exchange between the first compressed fluid and a pre-cooling fluid to cool the pre-cooling fluid, - a step 720 of expansion of the first fluid downstream 715 of the heat exchange step, - a step 725 of compression of the pre-cooling fluid, supplied with mechanical energy by a step 730 of conversion of the mechanical expansion energy obtained during the expansion step 720, - a step 735 of expansion of the pre-cooling fluid at the outlet of the heat exchange step and - a pre-cooling step 740 between the expanded pre-cooling fluid and the target fluid to cool the target fluid.

[0121] Particular embodiments of the steps of the method 700 which is the subject of the present invention are described with reference to FIGS. 1 to 6.

[0122] .

Claims

Claims

1. Device (100, 200, 300, 400, 500, 600) for pre-cooling a target fluid, characterized in that it comprises: - an inlet (105) for a first fluid in the liquid phase, in which the first fluid is methane-rich gas, - a means (155) for compressing the first fluid in the liquid phase, - a heat exchanger (115) between the first compressed fluid and a pre-cooling fluid for cooling the pre-cooling fluid, - a turbocharger comprising an expander (120) for the first fluid downstream of the heat exchanger and a compressor (125) for the pre-cooling fluid, so as to form a converter (130) of mechanical expansion energy, obtained by the operation of the expander, into mechanical compression energy supplied to the compressor, - a means (135, 205,305) for expanding the pre-cooling fluid at the outlet of the heat exchanger and - a means (140) for pre-cooling between the expanded pre-cooling fluid and a target fluid for cooling the target fluid.,

2. The device (100, 200, 300, 400, 500, 600) of claim 1, wherein the target fluid is dihydrogen.

3. Device (100, 200, 300, 400, 500, 600) according to one of claims 1 or 2, which comprises means (145) for vaporizing the first fluid in liquid phase downstream of the regulator (120) of the first fluid and / or downstream of the inlet (105) for the first fluid.

4. Device (100, 200, 300, 400, 500, 600) according to one of claims 1 to 3, which comprises at least one additional heat exchanger (150, 151), between the first fluid and the pre-cooling fluid coming from the pre-cooling means (140), the pre-cooling fluid at the outlet of an additional heat exchanger being supplied to the compressor (125).

5. Device (100, 200, 300, 600) according to claim 4, in which at least two heat exchangers (115, 150) are combined.

6. Device (300, 500) according to one of claims 4 or 5, which comprises another turbocharger (306) configured to expand the pre-cooling fluid upstream of the pre- cooling and for compressing the pre-cooling fluid upstream of a heat exchanger (150).

7. Device (100, 200, 300, 400, 500, 600) according to one of claims 1 to 6, which comprises a heat exchanger (160) configured to heat the first fluid at the outlet of the heat exchanger (115) and to supply the first heated fluid to the expansion valve (120).

8. Device (600) according to one of claims 1 to 7, which comprises a compression block (101) of the target fluid and a circuit (605) for circulating a heat transfer fluid between the heat exchanger (160) and a compression block of the target fluid.

9. Method (700) for pre-cooling a target fluid, characterized in that it comprises: - a step (705) of inputting a first fluid in the liquid phase, in which the first fluid is methane-rich gas, - a step (706) of compressing the first fluid in the liquid phase, - a step (715) of heat exchange between the first fluid and a pre-cooling fluid to cool the pre-cooling fluid, - a step (720) of expanding the first fluid downstream of the heat exchange step, - a step (725) of compressing the pre-cooling fluid, supplied with mechanical energy by a step (730) of mechanical conversion of the expansion energy obtained during the expansion step, - a step (735) of expanding the pre-cooling fluid at the outlet of the heat exchange step and - a step (740) of pre-cooling between the pre-cooling fluid relaxed and the target fluid to cool the target fluid.

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