Patent Application
20240200868
The present invention is directed to a device for cooling a flow of a target fluid to a temperature of less than or equal to 90 K and a method for cooling a flow of a target fluid to a temperature of less than or equal to 90 K. It applies, for example, to the field of hydrogen liquefaction.
A fluid liquefaction method is schematically divided into three major temperature technology blocks: compression, pre-cooling and refrigeration. The purpose of pre-cooling, for example, is to lower inlet temperatures between 273 K and 320 K of a hydrogen flow of interest and the fluid used for refrigeration in the next block to a so-called pre-cooling temperature between 78 K and 120 K.
In known systems, the cooling step is historically performed using liquid nitrogen flowing in the opposite direction in a heat exchanger. This nitrogen enters at a temperature of about 78 K, exits at ambient temperature and is discharged into the atmosphere. Such systems are hereinafter referred to as “P1”.
In such systems, the implementation of an open loop of liquid nitrogen has the drawbacks of involving logistical management of its supply, storage of large amounts of nitrogen and low energy performance (approximately from 3.5 to 4.5 kWh/kg LH2). Economic and practical advantages of these systems are justified in the context of small productions of less than 5 tonnes per day, but are not viable or operationally complex beyond this. Finally, these systems are not suitable for productions in remote and hard-to-reach areas due to the need to create a liquid nitrogen supply chain.
Other known systems focus on recycling nitrogen in a closed cycle (or circuit). Such systems are hereinafter referred to as “P2”.
This is achieved by a series of compression and cooling operations with a final expansion allowing temperature of the nitrogen to be lowered to about 80 K. Using heat exchangers, fluids to be cooled are also brought to about 80 K. Such systems are hereinafter referred to as “P2.1”.
An improvement of this loop performs several expansion operations during cooling to optimise cold supply within the exchangers. Such systems are hereinafter referred to as “P2.2”.
An improvement of P2.2 can be achieved by implementing a so-called dual closed nitrogen cycle as there are two simultaneous inlet pressures in the compressors. Such systems are hereinafter referred to as “P2.3”.
All such systems are alternatives to solution P1 in that they operate in a closed nitrogen cycle, avoiding all the problems recited above. The P2.3 solution is an improvement of the P2.2 and P2.1 solutions making it possible to optimise cold supply within the exchangers. Nonetheless, these solutions require high investment in equipment, especially compressors, due to their high nitrogen throughput (approximately 8 tonnes per day to produce one tonne of liquid hydrogen per day).
Other systems known as “MRC” (Mixed-Refrigerant Cycle) use a mixture of hydrocarbons and nitrogen as a refrigerant, the composition of which varies depending on the solutions. By the same operating principle of compression, cooling and expansion, the refrigerant is cooled to about 90 to 130 K. Using heat exchangers, the fluids to be cooled are also brought to about 90 to 130 K. Such systems are hereinafter referred to as “P3”.
A variant to this solution produces cold in the 90-110K range using a blended refrigerant consisting of nitrogen, methane, ethane and propane. Such systems are hereinafter referred to as “P3.1”.
A variant to this solution applies the concept to hydrogen liquefaction with a three-stage expansion pre-cooling carried out through a Joule-Thomson valve (referred to as “J-T”). Such systems are hereinafter referred to as “P3.2”.
A variant provides a similar cycle, but turbines were used instead of J-T valves. On the other hand, the composition then comprised nitrogen, C1-C5 hydrocarbons, ethylene, tetrafluoromethane R14 and neon. Such systems are hereinafter referred to as “P3.3”.
One variant simplifies the single-stage expansion and five-component refrigerant (N2 and C1-C4) mixing cycle. Such systems are hereinafter referred to as “P3.4”.
Another variant also results in a simplified composition (H2, N2, C1, C2 and C4) in a three-stage expansion system and adds a compression stage partly performed by a pump. Such systems are hereinafter referred to as “P3.5”.
Another variant uses a two-stage expansion cooling mixing system, where compression is partly made with a pump and the composition is limited to four components (N2, C1, C2, iC4). Such systems are hereinafter referred to as “P3.6”.
These P3 systems resort to a combined cooling cycle and optimise the cycle energy efficiency compared to previous systems by enabling heat exchanges between cold and hot fluids to be adapted by virtue of successive partial evaporation operations of the different compounds. Variations between these solutions are due to changes in compositions, number of expansion stages and addition of a compression stage, partly provided by a pump.
However, pre-cooling using a mixed refrigerant described above allows the target fluid to be cooled down to a temperature limited to approximately 90K without the risk of crystallisation. This limit requires the cooling cycle to perform cooling above 90 K or take the risk of crystallisation, increasing the need for the compressive power thereof compared to a cycle using pure nitrogen.
US patent application 2018,347,897 A is known, which discloses a device for pre-cooling a target gas by implementing two separate cooling fluid circuits. However, such a device does not allow pre-cooling of a gas to a temperature below 90 K.
US patent application 2019,063,824 is also known, which discloses a device for pre-cooling a target gas by implementing four separate circuits of natural gas joint cooling and liquefaction fluid. However, such a device implements a large number of target fluid and cooling fluid circuits. Furthermore, this device is complex and costly due to the joint use of some elements, such as expansion turbines, in cooling circuits.
Scientific publication “A novel Hydro liquefaction process configuration with combined mixed refrigerant systems” by Asadnia et al is also known, which discloses a device for pre-cooling a target gas by implementing two separate cooling fluid circuits. However, such a device is complex due to some elements, such as expansion turbines, used in cooling circuits.
The present invention aims to remedy all or part of these drawbacks.
For this purpose, according to a first aspect, the present invention is directed to a device for pre-cooling a flow of a target gas at a temperature of less than or equal to 90 K, which comprises:
By virtue of these provisions, it is possible to achieve pre-cooling temperatures below 90K at low energy and economic cost while maintaining optimised exchanges enhanced between the refrigerant mixture and the fluids to be cooled without the risk of crystallisation.
The present invention is distinguished by a pre-cooling to overcome the compromise between energy efficiency and pre-cooling temperature found in existing solutions. Indeed, the method provided is both very energy efficient by virtue of the use of a mixture of refrigerants and both capable of reaching the coldest temperatures usually reached without risk of crystallisation by a pre-cooling circuit in the liquefaction of a target fluid, especially hydrogen, by virtue of the nitrogen loop.
The present invention thus makes it possible to significantly reduce energy consumption of the cooling circuit of the entire method.
Furthermore, the present invention makes it possible to avoid the use of an expansion turbine in the circulation circuit for a flow of the third cooling fluid. This simplifies the circuit, therefore reducing the cost of the device.
In embodiments, the circulation circuit for a flow of the third cooling fluid comprises at least one expansion stage for the flow of third fluid, the expansion stage comprising a Joule-Thompson valve, upstream of said at least one heat exchanger.
In embodiments, the circulation circuit for the flow of third fluid is configured so that the third cooling fluid has a mixture of liquid and gas downstream of the expansion stage.
In embodiments, the circulation circuit for the flow of third fluid is configured to pass through at least two of the heat exchangers of the heat exchanger group.
In embodiments, the circulation circuit for a flow of the third cooling fluid comprises the expansion stage for the flow of third fluid between a third fluid outlet of a heat exchanger among the two of said heat exchangers and a third fluid inlet of a heat exchanger among the two of said heat exchangers.
In embodiments, the circulation circuit for a flow of the third cooling fluid comprises at least one compression stage for the flow of the third fluid between a third fluid outlet of a heat exchanger among the two of said heat exchangers and a third fluid inlet of a heat exchanger among the two of said heat exchangers.
In embodiments, the circulation circuit for a flow is a closed circulation circuit for a flow of a third cooling fluid.
In embodiments, the circulation circuit for a flow is a closed circulation circuit for a flow of a third cooling fluid through at least two of said heat exchangers, comprising:
These embodiments make it possible to form pre-cooling with two integrated loops, further optimising the operation of the device.
In embodiments:
These embodiments make it possible to condition, in pressure, the third refrigerant fluid upstream of the injection of this fluid into the group of exchangers performing pre-cooling of the target fluid.
In embodiments:
These embodiments make it possible to regenerate frigories in the third fluid, in particular upstream of an inverse passage through the heat exchanger group.
In embodiments, the circulation circuit for a flow of a third fluid is an open circulation circuit for a flow of a third cooling fluid through at least one heat exchanger.
These embodiments make it possible to reduce the number of exchanger channels and decrease complexity of the refrigeration cycle in the event of a third fluid open circuit.
In embodiments, the open circulation circuit for the flow of third fluid is configured to pass through at least two of the heat exchangers of the heat exchanger group.
These embodiments make it possible to reduce the number of exchanger channels and decrease complexity of the refrigeration cycle in the event of a third fluid open circuit.
In embodiments, the flow of third cooling fluid is a nitrogen flow.
In embodiments, the flow of third cooling fluid has a liquefaction temperature at atmospheric pressure less than or equal to the liquefaction temperature at atmospheric pressure of the second cooling fluid.
In embodiments, the circulation circuit of the nitrogen flow is configured so that the nitrogen flow is constrained by at least one of the following operating conditions:
These operating conditions have the best pre-cooling efficiencies.
In embodiments:
These embodiments make it possible to restore part of the frigories of the second cooling fluid upstream of the complete or partial reverse passage through the heat exchanger group.
In embodiments:
These embodiments make it possible to condition the second cooling fluid upstream of the pre-cooling step.
In embodiments:
Separations make it possible to constitute flows mainly comprised of light species vaporising at low temperature and flows mainly comprised of heavy species vaporising at medium or high temperature (cryogenic baseline).
The benefits are many:
In embodiments:
In embodiments, the device object of the present invention comprises, downstream of a compression stage for the second cooling fluid:
In embodiments, the circulation circuit of the second refrigerant fluid is configured so that the flow of the second refrigerant fluid is constrained by at least one of the following operating conditions:
These operating conditions have the best pre-cooling efficiencies.
In embodiments, the flow of target fluid is a hydrogen and/or helium flow.
In embodiments, the flow of first refrigerant fluid is a flow comprising or at least or consisting of:
In embodiments, the flow of second refrigerant fluid is a flow comprising at least or consisting of a mixture from:
In embodiments, the flow of the second refrigerant fluid consists, in mole percent, of:
According to a second aspect, the present invention is directed to a method for pre-cooling a flow of a target gas to a temperature of less than or equal to 90 K, which comprises:
The method object of the present invention has the same advantages as the device object of the present invention.
Further particular advantages, purposes and characteristics of the invention will become clearer from the non-limiting description that follows of at least one particular embodiment of the device and method object of the present invention, with regard to the attached drawings, wherein:
This description is provided for non-limiting purposes, wherein each characteristic of an embodiment can be advantageously combined with any other characteristic of any other embodiment.
From now on, it is noted that the figures are not drawn to scale.
As used herein, “fluid” of a given compound denotes a fluid comprising at least said compound in major proportion. “Major proportion” refers to at least one relative major proportion.
In variants, the term “major proportion” means a proportion corresponding to at least 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95% or 99% in volume of the flow.
A “target fluid” denotes a gas to be liquefied by the action of one of the variants of the device or method object of the present invention. Such a gas may, for example, correspond to dihydrogen. Such a target fluid is, for example, configured to initially have a temperature of 298 K. Such a target fluid is, for example, configured to initially have a pressure of 21 bara.
“First cooling fluid” denotes any gas or liquid likely to allow the device or method to cool the target flow to a temperature of 90 K or less. Such a first fluid comprises at least or consists of, for example:
Such a flow of first fluid is, for example, configured to operate in a closed circuit between 298 K and 22 K as the circulation in the closed circuit proceeds.
“Second cooling fluid” denotes any gas or liquid likely to allow the device or method to cool the target flow to a temperature of 90 K or less and preferably 80 K or 83 K or less.
Preferably, the second refrigerant fluid circulating, for example, in a closed circulation circuit is in liquid or two-phase form, that is a liquid-gas mixture, in most of the circuit.
This second refrigerant fluid has several variants:
In a first variant, the second fluid consists of or comprises five compounds:
In a second variant, the second fluid consists of four compounds:
In a third variant, the second fluid consists of six compounds:
“Third cooling fluid” denotes any gas or liquid likely to allow the device or method to cool the target flow to a temperature of 90 K or less. In other words, the third cooling fluid has a circulation temperature in a heat exchanger of less than 90 K. Such a third fluid is, for example, nitrogen or argon.
In embodiments, the flow of third cooling fluid has a liquefaction temperature at a predetermined pressure, for example, at atmospheric pressure, less than or equal to the same predetermined pressure liquefaction temperature of the second cooling fluid.
In embodiments, the flow of third cooling fluid has a dew point less than or equal to the dew point of the second cooling fluid at a predetermined pressure, for example, at atmospheric pressure. Preferably, the flow of third cooling fluid also has a bubble point less than or equal to the bubble point of the second cooling fluid at a predetermined pressure, for example, at atmospheric pressure.
In the description below, “heat exchanger” denotes any heat exchanger likely to be suitable for the operating conditions allowing cooling of less than 90 K of the target fluid. For example, such a heat exchanger is a multiple-flow plate and fin heat exchanger.
It is noted that devices of the same type, for example compressors or exchangers, may not be separate devices, but stages of a single device for all or part of the devices of a given type. For example, the exchangers, 106, 107, 108 and 136, can correspond to three separate stages of a single exchanger.
A schematic view of one embodiment of the device 100 object of the present invention is observed in
In embodiments, the third fluid circulating in the circulation circuit 125 has a circulation temperature in an exchanger of less than 90 K. In other words, in these embodiments, the third cooling fluid cools the target fluid to a temperature of less than or equal to 90 K in such a heat exchanger.
In embodiments, the circuit 125 of circulating a flow of the third cooling fluid does not comprise an expansion turbine (“turboexpander”). In particular, the amount of frigories produced in the closed circuit 110 of the second circulation refrigerant fluid is sufficient to avoid the use of a circuit 125 expansion turbine for circulating a flow of the third cooling fluid. In other words, the closed circulation circuit 110 of the second refrigerant fluid, comprising different stages, is therefore sufficiently energy efficient and thus makes it possible to simplify the circulation circuit 125 for a flow of the third cooling fluid. In addition, the presence of an expansion turbine limits the use of the third fluid to specific pressure and temperature ranges, as such a fluid should remain in gas form during the expansion in order not to damage the turbine. Preferably, such a limitation should be avoided in circuit 125 of the third fluid since the liquid part of the third fluid participates in intensifying heat exchanges in one or more exchangers. In addition, such a liquid part of the third fluid allows effective cooling of the target fluid to a temperature of 90 K or less.
In embodiments, the circulation circuit 125 for the flow of the third cooling fluid comprises an expansion stage. Such a circulation circuit 125 for the flow of the third cooling fluid may be closed or open. Preferably, such an expansion stage does not have an expansion turbine (turboexpander).
In embodiments, the expansion stage of the circuit 125 of circulating a flow of the third cooling fluid is a Joule-Thompson valve. Even more preferentially, the flow of the third cooling fluid is a two-phase fluid, that is the flow of the third cooling fluid comprises a mixture of liquid and gas, downstream of the expansion stage.
The term group 105 denotes at least two exchangers, 106, 107, 108 and/or 136, preferably heat exchangers belonging to a group for pre-cooling the target fluid 101.
The group 105 of exchangers is characterised by the fact that, in at least one exchanger, 106, 107, 108 and/or 136, the target fluid flow 101, the first cooling fluid 102 and the second cooling fluid interact therein. This group 105 of exchangers may also, in variants, be a place of exchange between the aforementioned fluids and a third cooling fluid.
In at least one exchanger, 106, 107, 108 and/or 136, of the group 105 of exchangers, the first cooling fluid 102 has a temperature lower than the temperature of the target fluid 101 passing through each said exchanger, 106, 107, 108 and/or 136.
Preferably, each exchanger, 106, 107, 108 and 136, of the group 105 of exchangers has both the target fluid 101 and the first cooling fluid 102 passing therethrough. The target fluid 101 and the first cooling fluid 102 may circulate in a co-current and/or counter-current manner with each other.
The cooling device 100 may further comprise a plurality of additional heat exchangers downstream of the heat exchanger group 105. These heat exchangers correspond to the ordinary implementation of the cooling stage of a liquefaction device for the target fluid 101.
Thus, as is understood, in embodiments such as those shown in
At the outlet of these two stages, the liquefied target fluid 101 may be discharged or inserted into a gas-liquid separation stage, the liquid fraction of the target fluid 101 being discharged and the gaseous fraction of the target fluid 101 being recirculated in at least one of the exchangers of the pre- cooling or cooling stage.
Such a mechanism is represented in
The first refrigerant fluid 102 may pass through all or part of the heat exchangers through which the target fluid 101 passes, whether in group 105 of exchangers or in at least one exchanger positioned upstream or downstream of said group 105 of exchangers.
Preferably, the device 100 comprises a closed circulation circuit for the first refrigerant fluid 102 in all or part of the heat exchangers of the device, in the group 105 of exchangers, upstream and/or downstream of said group 105 of exchangers. In these embodiments, represented in
This closed circuit may comprise intermediate stages of compression, expansion, division or mixing of the flow 102 of the first refrigerant fluid, as represented in
The closed circulation circuit 110 of a flow of a second cooling fluid is intended to contribute to cooling, in at least one heat exchanger, 106, 107, 108 and/or 136, of the group 105 of exchangers, the first refrigerant fluid 102 and/or the target fluid 101.
The exact architecture of the circuit 110 depends on a compromise between theoretical performance and cycle complexity.
The number of exchangers is additionally related to the number of separations, as is the number of expansion operations related to the number of separation operations.
A circuit with a single separation (and therefore two exchangers and two expansions) is adapted if the composition of the refrigerant is adapted and the risks of crystallisation of the heaviest species at low temperatures are limited. Also, some variants do not implement separation. Such variants further restrict the composition and lowest achievable temperature.
Both variants degrade method performance by increasing energy consumption, but simplify the device variants set out in
Conversely, with additional separation (i.e. four exchangers and four expansion operations) reduces energy consumption, but makes the cycle more complex.
This closed circuit 110 comprises:
At least one compression stage, 111 and/or 112, or a compression means 150 is, for example, a turbocompressor, a mechanical or reciprocating compressor.
At least one liquid-gas separation stage, 115 and/or 116 is, for example, a separation column.
At least one expansion stage, 120, 121 and/or 122 is, for example, a Joule-Tompson valve. As is understood, there are many embodiments for this closed circuit 110.
In some embodiments, such as the one represented in
In some embodiments, such as that represented in
In some embodiments, such as the one represented in
In some embodiments, such as the one represented in
In some embodiments, such as that represented in
In some embodiments, such as that represented in
In some embodiments, such as the one represented in
In some embodiments, such as the one represented in
In some embodiments, such as the one represented in
In some embodiments, such as that represented in
In some embodiments, such as that represented in
In some embodiments, such as that represented in
In some embodiments, such as that represented in
In some embodiments, such as that represented in
In some embodiments, such as that represented in
As is understood, the following diagram can be implemented iteratively:
The last step, at the end of the iteration of the diagram, is characterised by the absence of separation upstream of injection in a heat exchanger.
In embodiments, such as those represented in
As is understood, there are many ways to implement the closed circuit 125. Below, several particular embodiments are set forth.
In a first embodiment, represented in
In embodiments, such as those represented in
Here, “successively” denotes a direct or indirect sequence of the staps of passing through the heat exchangers, 106, 107, 108 and/or 136, by the third cooling fluid.
In these embodiments, at least one compression stage 130 is positioned at the junction between a co-current through-passage and a counter-current through-passage of the third refrigerant fluid.
In embodiments, such as those represented in
In these embodiments, at least one expansion stage 135 is positioned at the junction between a co-current through-passage and a counter-current through-passage of the third refrigerant fluid.
In embodiments, such as that represented in
In these embodiments, the closed circuit 125 comprises a separator 202 positioned downstream of the compression stage 130 and upstream of the group 105 of heat exchangers, along the path in which the third refrigerant fluid travels. This separator 202 is configured to separate a predetermined or variable part, according to a command issued by an automaton for example. The part thus separated is provided to the dedicated heat exchanger 205 so as to cool the flow of the third decompressed refrigerant fluid from the expansion stage 135.
The third cooling fluid from the dedicated heat exchanger 205 is provided to a mixing means 201, in which said fluid and the part not provided to the dedicated heat exchanger 205 are mixed.
At the outlet of the mixing means 201, the third refrigerant fluid is provided to the expansion stage 135.
In embodiments, such as those represented in
In embodiments, preferably adapted to the embodiment represented in
In embodiments, preferably adapted to the embodiment represented in
For example, in variants, the target fluid flow 101 is comprised of normal hydrogen (25% para-hydrogen and 75% orthohydrogen) at 21 bara, 298K (25° C.) with a mass flow rate of 0,116 kg/s. The flow is first cooled to 90K (−183° C.) by three heat exchangers, 106, 107, 108 and 136. The target fluid 101 then enters a first heat exchanger 136, for example catalytic exchanger, performing the first step of the ortho-para conversion. The target fluid flow 101 exits the pre-cooling part at 80K (−193° C.) and 48% of para-hydrogen. In the downstream cooling section, the supply hydrogen reaches 26K (−247° C.) and 98% para-hydrogen through five serial catalytic heat exchangers (not referenced). The target fluid flow 101 is mixed with evaporative gas (boil-off gas) from the last stage of liquefaction and enters the last catalytic heat exchanger to reach 22K (−251° C.). At this stage, the supply hydrogen is at 22K (−251° C.), 20 bara and 99% para-hydrogen. The final liquefaction step is performed with a Joule-Thompson valve which lowers pressure to 2 bara. The liquid part of the flow (98%) exits the liquefier and the remaining gas part is liquefied.
Performing the conversion of orthohydrogen to parahydrogen during liquefaction can be performed in several ways and therefore leads to variants.
The advantage of using a catalytic exchanger is to carry out a first stage of conversion in the pre-cooling circuit to avoid doing so in the cooling circuit.
However, there may not be a catalytic exchanger and a dedicated reactor can be used, or even a conversion may not be performed at this location.
The general idea is to perform a conversion step and dissipate conversion heat with the third refrigerant, especially with a catalytic exchanger.
In variants, the circuit 102 of first refrigerant fluid is a double pressure Claude loop and the refrigerant used is normal hydrogen. The refrigerant fluid is first compressed to 29 bara by a multi-stage compressor (not referenced). The fluid is cooled to 90 K (−183° C.) in three heat exchangers, 106, 107, 108 and 136 by exchange against the flow of the third refrigerant fluid, then cooled to 80 K (−193° C.) in the exchanger 136 by exchange against the flow of the third refrigerant fluid. The first refrigerant fluid then enters the cooling section and is cooled to 69 K (−204° C.) in the first cooling heat exchanger (not referenced). The refrigerant is separated, 89% of the total flow rate is expanded to 18.5 bara and reaches 60K (−213° C.). The first refrigerant fluid is then cooled to 51K (−222° C.) in a heat exchanger (not referenced) and is again expanded with a two-stage expander to 4.5 bara to reach 31.5K (−241.5° C.). From this point on, the first refrigerant fluid is used as a refrigerant in the first four cooling heat exchangers (not referenced). The remaining part (11%) is cooled to 26K through four heat exchangers (not referenced). This part is then expanded with a Joule-Thompson valve to 1.5 bara to reach 22K. The liquid refrigerant cools the target fluid 101 to 22K in two (unreferenced) two-phase heat exchangers and seven multi-flow heat exchangers, comprising the heat exchanger group 105 and exchanger 136. The two refrigerant flows at 4.5 and 1.5 bara exit the pre-cooling part at ambient temperature. The one at low pressure is compressed to 4.5 bara in a first compressor (not referenced). It is then mixed with the medium pressure flow before entering the second compression stage (not referenced).
The third refrigerant fluid, for example nitrogen, cools the target fluid 101 from 90 K (−183° C.) to 80 K (−193° C.). Nitrogen is first compressed from 1 bara to 40 bara by a multi-stage compressor 130. Nitrogen is then cooled to 90 K (−183° C.) in three heat exchangers, 106, 107, 108 and 136. Nitrogen is then partially liquefied using a Joule-Thompson valve to reach 78 K (−195° C.) and nitrogen operates in the heat exchanger 106 as the main refrigerant. The remaining cooling capacity of nitrogen is used in the pre-cooling heat exchangers 106, 107, 108 and 136.
In variants, the second refrigerant fluid comprises a mixture of five components, the mole percents of which, relative to the total amount of the mixture of the five components, are as follows: R728 (nitrogen), 4-14%, R50 (methane) 26.4-40%, R1150 (ethylene) 14.9-36.4%, R290 (propane) 21.5-35% and R600 (butane) 14.8-25%. These refrigerants have different boiling points ranging from 78K (−195° C.) to 261K (−12° C.) at atmospheric pressure, making the second refrigerant partially liquid during most of the process.
The second refrigerant fluid is first compressed from 1 bara to 11 bara by a compression stage 111. At 11 bara a liquid fraction appears (about 10%) after intermediate cooling to ambient temperature, the phases are separated and the gas part finishes its compression in a compressor 112 while the liquid part finishes it in a pump 150. The use of a pump reduces the compression power and thus the energy consumption of the facility. The compressed flows are then mixed and the phases are separated again. The liquid part (30%) is cooled to 182K (−91° C.) in the first heat exchanger 106 and expanded with a Joule-Thompson valve at 1 bara. The gas part (80%) is cooled to 182K (−91° C.) in the first heat exchanger 106 and the phases are separated once again. The liquid part (73%) is cooled to 115K (−158° C.) in the intermediate heat exchanger 107 and expanded to 1 bara with a Joule-Thompson valve. The gas part (27%) is cooled to 90K (−183° C.) in two heat exchangers, 107 and 108, before being expanded in a Joule-Thompson valve to 1 bara and providing its cold power in the heat exchanger 108. The two previous flows are mixed and provide cooling power to the heat exchanger 107. Finally, the remaining two flows are mixed, provide cooling power in the first heat exchanger 106 and are provided to the compression stage 111.
In
This method is described, mutatis mutandis, in different embodiments and variants, with respect to the device, 100, 200, 300, and/or 400, illustrated in
In
This sub-method 600 comprises:
A succession of particular steps of the sub-method 700 object of the present invention is schematically observed in
This sub-method 700 comprises:
In a variant, step 720 is performed only in the exchanger 136.
A sequence of particular steps of the sub-method 800 object of the present invention is schematically observed in
This sub-method 800 comprises:
| Number | Date | Country | Kind |
|---|---|---|---|
| FR2105723 | May 2021 | FR | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2022/064796 | 5/31/2022 | WO |
