WO2022263754A1

WO2022263754A1 - System for recovering compression energy of a gas, liquefier comprising such a system and method for recovering compression energy of a gas

Info

Publication number: WO2022263754A1
Application number: PCT/FR2022/051117
Authority: WO
Inventors: Davide DURI; Loïc PENIN; Géraldine PALISSAT; Louis-Vianney Mabille De La Paumeliere; Pierre CHABERNAUD
Original assignee: Arianegroup Sas
Priority date: 2021-06-16
Filing date: 2022-06-13
Publication date: 2022-12-22
Also published as: EP4355985A1; FR3124247A1; FR3124247B1

Abstract

System for recovering compression energy of a gas (56), the system comprising an organic Rankine cycle module (40) and an adiabatic compressor (14), the organic Rankine cycle module (40) containing a heat-transfer fluid (54) and the adiabatic compressor comprising N adiabatic gas compression stages (14A, 14B, 14C), N being greater than or equal to 2, and, downstream of each adiabatic gas compression stage (14A, 14B, 14C), two heat exchangers, a first heat exchanger (50A, 50B, 50C) configured to extract heat from the gas leaving the adiabatic compression stage (14A, 14B, 14C) and to heat the heat-transfer fluid (54) passing through the first heat exchanger (50A, 50B, 50C), and a second heat exchanger (52A, 52B, 52C) configured to extract heat from the gas leaving the first heat exchanger (50A, 50B, 50C) towards a cold source (58) passing through the second heat exchanger (52A, 52B, 52C). Liquefier comprising such a system and method for recovering compression energy of a gas.

Description

GAS COMPRESSION ENERGY RECOVERY SYSTEM, LIQUEFACTOR COMPRISING SUCH A SYSTEM AND GAS COMPRESSION ENERGY RECOVERY METHOD

Technical area

This presentation relates to the compression of a gas and in particular the recovery of gas compression energy.

Prior technique

[0002] The liquefaction of a gas generally requires a step of compressing the gas at high pressure. This compression stage is qualified as isothermal and is generally carried out by a succession of adiabatic compression stages during which the gas is heated. Thus, between each compression stage, the gas is cooled before entering the next compression stage.

[0003] The gas is cooled in a heat exchanger. In liquefiers, also called "liquefier" in English, the heat recovered in this heat exchanger is either lost to the atmosphere or, for example as described in JP2005241232, used as a hot source for the vaporization of natural gas liquid.

[0005] The liquefier-liquefied natural gas installation coupling implies that the liquefier and the liquefied natural gas installation are in the same place. Also, this heat recovery solution greatly limits the possibility of recovering this heat, in particular the number of liquefied natural gas installation sites, the fluctuation in demand for liquefied natural gas which will have an impact on cooling compressed gas between two compression stages as well as safety constraints linked to the presence of liquefied natural gas and liquid hydrogen, for example.

Disclosure of Invention

[0006] This presentation aims to remedy, at least in part, these disadvantages.

To this end, the present presentation relates to a system for recovering energy from the compression of a gas, the system comprising an organic Rankine cycle module and an adiabatic compressor, the organic Rankine cycle module comprising a fluid coolant and the adiabatic compressor comprising N stages of adiabatic compression of the gas, N being greater than or equal to 2, and, downstream of each stage of adiabatic compression, two heat exchangers, a first heat exchanger configured to extract heat from the gas leaving the adiabatic compression stage and reheating the heat transfer fluid passing through the first heat exchanger and a second heat exchanger configured to extract heat from the gas leaving the first heat exchanger to a cold source passing through the second heat exchanger.

[0008] Subsequently, the terms “upstream” and “downstream” are defined with respect to the normal flow direction of the gas in the system. Thus, a second element arranged downstream of a first element receives the gas which leaves the first element.

[0009] Thanks to the organic Rankine cycle module, it is possible not to lose the heat of the gas compressed in an adiabatic compression stage to the atmosphere, and this, by overcoming the constraint of direct coupling with a unit of liquefied natural gas.

In known manner, an organic Rankine cycle module comprises at least one heat exchanger configured to heat the heat transfer fluid circulating in the module from a heat source external to the module, a device for expanding the heated heat transfer fluid, a condenser to cool the heat transfer fluid and a pump to circulate the heat transfer fluid in the module. The expansion device makes it possible to expand the heated and pressurized heat transfer fluid and to transform the energy recovered in the form of heat into mechanical energy. The expansion device is generally coupled to an energy recovery device making it possible to transform the mechanical energy recovered at the output of the expansion device into usable energy. In the present presentation, the hot source is the gas leaving a compression stage of the adiabatic compressor. [0011] The system comprising, after each compression stage, a first heat exchanger configured to exchange heat between the gas leaving a compression stage and the heat transfer fluid of the organic Rankine cycle module, part of the heat generated during the adiabatic compression of the gas is recovered in the heat transfer fluid of the organic Rankine cycle module, the heated heat transfer fluid is then expanded in order to produce energy.

By way of non-limiting example, the expansion device can be a turbine or a volumetric expansion device, for example of the spiral type, also identified according to the term in English as “scroll” type volumetric expansion devices. . In general, for large expansion ratios, for example greater than or equal to 7, preference will be given to a turbine and for lower expansion ratios, preference will be given to a volumetric expansion device. Criteria other than the expansion ratio can also be taken into consideration in the choice of the expansion device.

[0013] By way of non-limiting example, the expansion device can be coupled to an electric generator to recover energy in electrical form.

[0014] It is also possible to envisage coupling another device to the expansion device to transform the energy into mechanical energy.

[0015] The coupling of the organic Rankine cycle module with the first heat exchangers makes it possible to increase the flow rate of the coolant which is vaporized and thus increase the size of the turbine. When the size of the turbine is increased, the relative clearances in the turbine decrease and therefore the performance of the turbine is improved, thus making it possible to increase the efficiency of energy recovery.

[0016] The electrical energy produced can be used to power components of the system itself or components external to the system, or even be injected into the electrical network.

[0017] By way of non-limiting example, the compressor of the isothermal compression stage can be a volumetric compressor or a centrifugal compressor.

[0018] In certain embodiments, the second heat exchanger can be a gas-air exchanger. [0019] In certain embodiments, the second heat exchanger can be a gas-water exchanger.

[0020] In some embodiments, the heat transfer fluid may have a boiling point between an inlet temperature of the cold source and an outlet temperature of the gas in the adiabatic compression stage.

[0021] In certain embodiments, the heat transfer fluid can be methanol, isobutane or ethanol.

This presentation also relates to a liquefier comprising a system as defined above.

[0023] The electrical energy produced can be used to supply components of the liquefier itself or components external to the liquefier, or even be injected into the electrical network. The energy recovery can be around 2% to 5% of the power required to operate the liquefier, which is not negligible with regard to the service life of a liquefier, which can be at least 20 years.

[0024] In certain embodiments, the gas may be the gas to be liquefied.

[0025] In certain embodiments, the liquefier may be a refrigerated liquefier comprising at least one cooling circuit and the gas is the gas from the at least one cooling circuit of the refrigerated liquefier and/or the gas to be liquefied.

In the case of a refrigerated liquefaction cycle with multiple cooling circuits, the gas compression energy recovery system can be implemented at the level of the compression stages of at least one cooling circuit. cooling.

It is understood that the gas of the cooling circuit of the refrigerated liquefier can be a pure gas or a mixture of gases. Pure gas means a gas comprising at least 99% of a gaseous compound.

[0028] In certain embodiments, the gas to be liquefied can be hydrogen, nitrogen, helium or natural gas.

This presentation also relates to a method for recovering energy from the compression of a gas, the method comprising the following steps: a) adiabatic compression of the gas in an adiabatic compression stage; b) extracting part of the heat from the gas compressed in a first heat exchanger comprising a heat transfer fluid from an organic Rankine cycle module; c) extracting part of the heat from the gas coming from the first heat exchanger in a second heat exchanger comprising a cold source; repeating steps a) to c) N times, N being greater than or equal to 2; using the heat extracted in the first heat exchanger to generate power in the organic Rankine cycle module.

Brief description of the drawings

Other characteristics and advantages of the object of this presentation will emerge from the following description of embodiments, given by way of non-limiting examples, with reference to the appended figures.

[0031] [Fig. 1] Figure 1 is a schematic view of a liquefier.

[0032] [Fig. 2] Figure 2 is a schematic view of a gas compression energy recovery system.

[0033] [Fig. 3] Figure 3 is a schematic view of a compression stage of the system of Figure 2.

[0034] [Fig. 4] FIG. 4 is a flowchart representing the steps of a method for recovering energy from the compression of a gas.

In all of the figures, the elements in common are identified by identical reference numerals.

detailed description

Figure 1 is a schematic view of a liquefier 10, for example a hydrogen (H ₂ ) liquefier using the Collins cycle. A liquefier comprises a cold box 12, also designated by the expression “Cold box” in English, an adiabatic compressor 14 and a heat exchanger 16 supplying the cold box 12 with pressurized hydrogen. The whole of the adiabatic compressor 14 and of the heat exchanger 16 forming an isothermal compressor. The cold box 12 is known per se and comprises a plurality of regenerators 18 arranged in series to arrive at a liquid hydrogen storage tank 24 passing through a Joie-Thompson isenthalpic expansion valve 22. Part of the hydrogen, in gaseous form, leaving a regeneration stage 18 is directed to a heat exchanger 20 and redirected to the adiabatic compressor 14.

For simplicity, the adiabatic compressor 14 and the heat exchanger 16 have been shown in Figure 1 as single elements. However, the adiabatic compressor 14 is an adiabatic compressor comprising several stages of adiabatic compression 14A, 14B, 14C, as shown in Figure 2. Likewise, the heat exchanger 16 comprises a plurality of heat exchangers 50, 52. In particular, the heat exchanger 16 comprises, downstream of each adiabatic compression stage 14A, 14B, 14C, two heat exchangers.

In the embodiment of Figure 2, the adiabatic compressor 14 comprises three stages of adiabatic compression 14A, 14B, 14C. Also, N the number of adiabatic compression stages is equal to 3. It is understood that N is not limited to 3 as long as N is greater than or equal to 2.

In the embodiment of Figure 2, downstream of each adiabatic compression stage 14A, 14B, 14C, the heat exchanger 16 comprises a first heat exchanger 50A, 50B, 50C and a second heat exchanger. heat 52A, 52B, 52C.

Figure 2 shows a compression energy recovery system of the gas to be liquefied from the liquefier, for example hydrogen. The energy recovery system includes the adiabatic compressor 14 and the heat exchanger 16. The energy recovery system also includes a module 40 organic Rankine cycle. In the embodiment of Figure 2, the gas 56 to be compressed enters the first adiabatic compression stage 14A. The first adiabatic compression stage 14A is supplied with gas 56 by a supply line 26 and by the gas recovered from the cold box 12 by a line 28.

The organic Rankine cycle module 40 comprises a heat transfer fluid 54 circulating in the module 40.

In the embodiment of Figure 2, the organic Rankine cycle module 40 comprises three first heat exchangers 50A, 50B, 50C configured to heat the heat transfer fluid 54 circulating in the module 40 from a heat source external to module 40, an expansion device 42, a condenser 46 to cool the heat transfer fluid 54 and a pump 48 to circulate the heat transfer fluid 54 in the module 40. The expansion device 42 makes it possible to expand the heat transfer fluid 54 heated in the heat exchangers 50A, 50B, 50C and under pressure and to transform the energy recovered in the form of heat into mechanical energy. By way of non-limiting example, the expansion device 42 can be a turbine or a volumetric expansion device.

In the embodiment of Figure 2, the expansion device 42 is coupled to an energy recovery device 44.

By way of non-limiting example, the expansion device 42 can be a turbine and the energy recovery device 44 can be an electric generator to transform the mechanical energy recovered from the turbine into electrical energy. It is understood that the expansion device 42 of the organic Rankine cycle module 40 can be coupled to another energy recovery device 44, allowing for example to transform the recovered energy into mechanical form, for example.

In the embodiment of Figure 2, the hot source is the gas 56 leaving the compression stages 14A, 14B, 14C and the condenser 46 is a heat exchanger using ambient air 60 as a cold source to cool the heat transfer fluid 54 which came out of the expansion device 42.

The heat transfer fluid 54 successively passes through the first heat exchangers 50A, 50B, 50C, where, by heat exchange with the gas 56 leaving the compression stages 14A, 14B, 14C, the heat transfer fluid 54 is brought to a boil . The heat transfer fluid 54, in the form of vapor, is then expanded in the expansion device 42 which is coupled to the energy recovery device 44. The vapor is then condensed in the condenser 46 by exchange with the ambient air 60. The heat transfer fluid 54 is again in the form of liquid and can once again travel through the first heat exchangers 14A, 14B, 14C.

The gas 56 at the outlet of each adiabatic compression stage 14A, 14B, 14C passes through the first heat exchanger 50, 50B, 50C and exchanges part of the heat stored in the gas 56 during compression with the coolant 54 circulating in the first heat exchanger 50A, 50B, 50C. The gas 56 leaving the first heat exchanger 50A, 50B, 50C then passes through the second heat exchanger 52A, 52B, 52C and exchanges the rest of the stored heat with a cold source 58. By way of non-limiting example, the cold source 58 can be the ambient air or water.

At the outlet of the second heat exchanger 52A, 52B, the gas 56 enters the adiabatic compression stage arranged downstream of the second heat exchanger 52A, 52C. At the outlet of the second heat exchanger 52C disposed downstream of the last adiabatic compression stage 14C, the gas 56 is sent to the cold box through a pipe 30.

By way of non-limiting example, the heat transfer fluid 54 can be methanol. Methanol has a boiling temperature at 1 bar approximately equal to 338 K (Kelvin) and the cold source 58 can be ambient air estimated at 300 K. For simplicity of representation, FIG. 3 represents a single stage adiabatic compression, for example the first adiabatic compression stage 14A. The elements common to the different figures are identified by the same reference numerals.

By way of non-limiting example, the temperature of the gas at the outlet of the adiabatic compression stage will be limited to 400 K. Also, the boiling temperature of the heat transfer fluid 54 is between the temperature of the temperature of entry of the cold source 58 into the second heat exchanger 52A, 52B, 52C and the temperature of the gas at the outlet of the adiabatic compression stage 14A, 14B, 14C.

Thus, in an ideal example, the hydrogen entering the first adiabatic compression stage 14A has an ambient temperature of approximately 300 K (item 1 in FIG. 3). After adiabatic compression, the hydrogen leaves at a temperature of 400 K (item 2 in FIG. 3). After passing through the first heat exchanger 50A, the gas 56 is at a temperature of 338 K (item 3 in FIG. 3), which is the boiling temperature of the heat transfer fluid 56). After passing through the second heat exchanger 52A, the gas 56 is at a temperature of approximately 300 K (item 4 in FIG. 3). It is understood that in practice, in a non-ideal system, the temperature of gas 56 will be slightly higher than 338 K. Similarly, after passing through the second heat exchanger 52A, the temperature of gas 56 will be slightly higher than the temperature of Ambiant air. The compression energy recovery system can also be implemented in a refrigerated liquefaction cycle.

Refrigerated liquefaction cycles are well known in the state of the art and implement cooling/refrigeration circuits of the gas to be liquefied by using another gas or a mixture of gas maintained at low temperature by a refrigeration cycle which comprises compression stages specific to this gas or this gaseous mixture and expansion stages, this other gas or gas mixture being used as refrigerant for the main liquefaction circuit. The nature of the gases or mixtures of gases used as refrigerant gases in such cycles can be distinct from the nature of the gas to be liquefied in the main liquefaction circuit.

It is then understood that in the context of a refrigerated liquefaction cycle, the compression energy recovery system can be implemented at the level of the compression stages specific to the cooling circuit of the refrigerated liquefaction cycle.

In the case of a refrigerated liquefaction cycle with multiple cooling circuits, the gas compression energy recovery system can be implemented at the level of the compression stages of one or more circuits. cooling.

The method 100 of gas compression energy recovery 56 will be described with reference to Figures to 4.

The method 100 comprises: a) an adiabatic compression step 102 of the gas 56 in an adiabatic compression stage 14A, 14A, 14C; b) a step 104 for extracting part of the heat from the gas compressed in a first heat exchanger 50A, 50B, 50C comprising the heat transfer fluid 54 of the module 40 with an organic Rankine cycle; c) a step 106 of extracting part of the heat from the gas coming from the first heat exchanger 50A, 50B, 50C in a second heat exchanger 52A, 52B, 52C comprising a cold source 58;

Steps a) to c) are repeated 108 N times, N being greater than or equal to 2.

In the embodiment of Figure 2, steps a) to c) are repeated three times. The method 100 includes a step 110 of using the heat extracted in the first heat exchanger 50A, 50B, 50C to produce energy in the organic Rankine cycle module 40.

[0066] Although this presentation has been described with reference to a specific embodiment, it is obvious that various modifications and changes can be made to these examples without departing from the general scope of the invention as defined by the claims. Further, individual features of the various embodiments discussed may be combined in additional embodiments. Accordingly, the description and the drawings should be considered in an illustrative rather than restrictive sense.

Claims

[Claim 1] A gas compression energy recovery system (56), the system comprising an organic Rankine cycle module (40) and an adiabatic compressor (14), the organic Rankine cycle module (40) Rankine comprising a heat transfer fluid (54) and the adiabatic compressor (14) comprising N adiabatic compression stages (14A, 14B, 14C) of the gas, N being greater than or equal to 2, and, downstream of each adiabatic compression stage ( 14A, 14B, 14C), two heat exchangers, a first heat exchanger (50A, 50B, 50C) configured to extract the heat from the gas leaving the adiabatic compression stage (14A, 14B, 14C) and heat the fluid coolant (54) passing through the first heat exchanger (50A, 50B, 50C) and a second heat exchanger (52A, 52B, 52C) configured to extract heat from gas exiting the first heat exchanger (50A, 50B, 50C) to a cold source (58) passing through the second heat exchanger (52A, 52B, 52C).

[Claim 2] A system according to claim 1, wherein the second heat exchanger (52A, 52B, 52C) is a gas-air exchanger.

[Claim 3] A system according to claim 1, wherein the second heat exchanger (52A, 52B, 52C) is a gas-water exchanger.

[Claim 4] A system according to any one of claims 1 to 3, wherein the heat transfer fluid (54) has a boiling temperature between an inlet temperature of the cold source (58) and an outlet temperature of the gas in the adiabatic compression stage (14A, 14B, 14C).

[Claim 5] A system according to claim 4, wherein the heat transfer fluid (54) is methanol, isobutane or ethanol.

[Claim 6] A liquefier (10) comprising a system according to any one of claims 1 to 5.

[Claim 7] A liquefier (10) according to claim 6, wherein the gas is the gas to be liquefied.

[Claim 8] Liquefier according to claim 6, in which the liquefier is a refrigerated liquefier comprising at least one cooling circuit and the gas is the gas from the at least one cooling circuit of the refrigerated liquefier and/or the gas to be liquefied.

[Claim 9] A liquefier (10) according to claim 7 or 8, wherein the gas (56) to be liquefied is hydrogen, nitrogen, helium or natural gas.

[Claim 10] A method (100) of recovering compression energy from a gas, the method comprising the steps of: a) adiabatically compressing (102) gas in an adiabatic compression stage (14A, 14B, 14C); b) extracting (104) part of the heat from the gas compressed in a first heat exchanger comprising a heat transfer fluid (54) from an organic Rankine cycle module (40); c) extracting (106) part of the heat from the gas coming from the first heat exchanger (50A, 50B, 50C) in a second heat exchanger (52A, 52B, 52C) comprising a cold source (58); repeating (108) steps a) to c) N times, N being greater than or equal to 2; using (110) the heat extracted in the first heat exchanger (50a, 50B, 50C) to generate power in the organic Rankine cycle module (40).