Cryogenic gas cooling system and method

Abstract

The pre-cooling heat exchanger system receives the flow of the first cryogenic fluid and heats the second cryogenic fluid. The first splitter receives the flow of the first cryogenic fluid and splits it into a drive flow and a secondary cooling flow. The ejector receives the drive flow. The expansion device receives the secondary cooling flow and expands it, directing at least a portion of it to the pre-cooling heat exchanger system, which in turn cools the second cryogenic fluid. The first cryogenic fluid from the pre-cooling heat exchanger is directed to the ejector suction port, where its pressure decreases. The main separator splits the mixed-phase flow of the first cryogenic fluid from the ejector into a first cryogenic fluid vapor flow and a liquid recycle flow that exit the main separator. The recycle pump directs the first cryogenic fluid to the first splitter.

Description

Technical Field

[0001] Claims of Priority

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 495,681, filed on April 12, 2023, the content of which is incorporated herein by reference.

[0002]

[0002] The present disclosure generally relates to systems and methods for performing refrigeration using cryogenic gases, and more particularly, to systems and methods for pre-cooling cryogenic gases using a cryogenic pre-cooling loop.

Background Art

[0003]

[0003] Liquid natural gas (LNG) pre-cooling for air separation and the liquefaction of hydrogen and other cryogenic gases is known in the art. In many cases, LNG is vaporized in a heat exchanger to pre-cool nitrogen in a nitrogen cooling cycle.

[0004]

[0004] In hydrogen liquefaction applications, a nitrogen cooling cycle typically pre-cools the hydrogen gas to be liquefied (e.g., to about -190°C). The pre-cooled hydrogen gas is then typically further cooled (e.g., to about -253°C) and liquefied in one or more additional cooling cycles using a hydrogen or helium refrigerant. As a result, typical liquefaction processes consume large amounts of energy. Further, this process includes multiple refrigeration cycles and may involve multi-stage gas compression.

[0005]

[0005] The natural gas resulting from the evaporation of LNG is typically used in subsequent processes, so the evaporation pressure of LNG is kept sufficiently high, e.g., often higher than 0.3 MPa (absolute pressure) (3 bar (absolute pressure)). At this pressure, the boiling temperature of LNG is 126.7 K. The boiling temperature of LNG is even higher at higher pressures (e.g., 144.2 K at 0.8 MPa (absolute pressure) (8 bar (absolute pressure))). Such high boiling temperatures limit the cooling performed by the evaporation of LNG.

[0006]

[0006] It is desirable to improve the efficiency of using cryogenic fluids such as LNG and nitrogen in the pre-cooling loop. [Overview of the Initiative]

[0007]

[0007] The subject matter includes several embodiments that can be implemented individually or in combination in the methods, apparatus, and systems described below and claimed. These embodiments can be used individually or in combination with other embodiments of the subject matter described herein, and the joint description of these embodiments is not intended to prevent the use of these embodiments individually or to claim embodiments individually or in different combinations as described in the claims attached herein.

[0008]

[0008] In one embodiment, a system for pre-cooling a second cryogenic fluid using a first cryogenic fluid includes a pre-cooling heat exchanger system comprising a primary heating passage, a secondary heating passage, and at least one cooling passage. The primary heating passage is configured to receive a flow of the first cryogenic fluid to heat the second cryogenic fluid in at least one cooling passage. A first splitter is configured to receive the first cryogenic fluid flow and split the first cryogenic fluid flow into a drive flow and a secondary cooling flow. An ejector has an ejector inlet, an ejector outlet, and a suction port. The ejector inlet is configured to receive the drive flow from the first splitter. An expansion device is configured to receive and expand the secondary cooling flow from the first splitter and direct at least a portion of the expanded secondary cooling flow into the secondary heating passage of the pre-cooling heat exchanger system, thereby cooling the second cryogenic fluid in at least one cooling passage of the heat exchanger system. The secondary heating passage of the pre-cooling heat exchanger system is in fluid communication with the ejector's suction port, and as a result, the first cryogenic fluid from the secondary heating passage is guided to the ejector's suction port, and the pressure in the secondary heating passage decreases. The main separator has a main separator inlet, a main separator vapor outlet, and a main separator liquid outlet. The main separator inlet is in fluid communication with the ejector outlet and splits the first cryogenic fluid mixed phase flow into a first cryogenic fluid vapor flow that exits the main separator through the main separator vapor outlet and a liquid recycle flow that exits the main separator through the main separator liquid outlet. The recycle pump has a pump inlet that is in fluid communication with the main separator liquid outlet and a pump outlet configured to guide the first cryogenic fluid to a first splitter.

[0009]

[0009] In another embodiment, a method for pre-cooling a second cryogenic fluid using a first cryogenic fluid includes the steps of: dividing a first cryogenic fluid flow into a drive flow and a secondary cooling flow; directing the drive flow to an ejector having a suction port; expanding the secondary cooling flow; cooling a second cryogenic fluid using at least a portion of the expanded secondary cooling flow, thereby forming a heated first cryogenic fluid; directing the heated first cryogenic body to a suction port of the ejector; separating a first cryogenic fluid mixed phase flow from the outlet of the ejector into a vapor flow and a liquid recycle flow; and pumping at least a portion of the liquid recycle flow for use as the first cryogenic fluid flow in the first step.

[0010]

[0010] In yet another embodiment, a system for liquefying a cryogenic gas supply stream includes a first pre-cooling heat exchanger, a second pre-cooling heat exchanger, a liquefaction heat exchanger, a natural gas pre-cooling refrigeration circuit, a nitrogen pre-cooling refrigeration circuit, and a main refrigeration circuit.

[0011]

[0011] The natural gas pre-cooling refrigeration circuit includes a liquid natural gas heating passage of a first pre-cooling heat exchanger configured to receive and heat a liquid natural gas supply flow. A first pre-cooling expansion device is configured to receive a fluid flow from the liquid natural gas heating passage of the first pre-cooling heat exchanger. A first pre-cooling separation device has a first pre-cooling separation device vapor outlet configured to guide the fluid to the inlet of the natural gas heating passage of the first pre-cooling heat exchanger. The first pre-cooling separation device also has a first pre-cooling separation device liquid outlet configured to receive and separate a fluid flow from the first pre-cooling expansion device, so that the natural gas vapor flow exits the first pre-cooling separation device vapor outlet and the liquid natural gas flow exits the first pre-cooling separation device liquid outlet. A second pre-cooling expansion device is configured to receive a liquid natural gas flow from the first pre-cooling separation device liquid outlet and guide the expansion fluid flow to the inlet of the expansion fluid heating passage of the first pre-cooling heat exchanger. The first pre-cooling compressor has an inlet that is in fluid communication with the outlet of the expansion fluid heating passage of the first pre-cooling heat exchanger, in order to reduce the pressure in the expansion fluid heating passage.

[0012]

[0012] The nitrogen pre-cooling refrigeration circuit includes a nitrogen cooling passage in the first heat exchanger. A third pre-cooling expansion device is configured to receive and expand the fluid flow from the nitrogen cooling passage in the first heat exchanger. A second pre-cooling separation device has an inlet configured to receive the expanding fluid from the third pre-cooling separation device, a second pre-cooling separation device vapor outlet, and a second pre-cooling separation device liquid outlet. The second pre-cooling separation device is configured to receive and separate the fluid flow from the third pre-cooling expansion device, so that the nitrogen vapor flow exits the second pre-cooling separation device vapor outlet and the liquid nitrogen flow exits the second pre-cooling separation device liquid outlet. The second pre-cooling heat exchanger has a liquid nitrogen heating passage configured to receive and heat the liquid nitrogen flow from the second pre-cooling separation device liquid outlet. The first pre-cooling heat exchanger has a nitrogen vapor heating passage having an outlet for the liquid nitrogen heating passage of the second pre-cooling heat exchanger and an inlet that is in fluid communication with the second pre-cooling separation device vapor outlet. The nitrogen compression cooling system has an inlet that is in fluid communication with the outlet of the nitrogen vapor heating passage, and an outlet that is in fluid communication with the nitrogen cooling passage of the first heat exchanger.

[0013]

[0013] The main refrigeration circuit includes a first main refrigerant pre-cooling passage in a first pre-cooling heat exchanger and a second main refrigerant pre-cooling passage in a second pre-cooling heat exchanger, each configured to receive and pre-cool a flow of main refrigerant. A main refrigerant adsorbent is configured to receive a pre-cooled flow of main refrigerant from the second main refrigerant pre-cooling passage of the second pre-cooling heat exchanger. A liquefied main refrigerant cooling passage in a liquefied heat exchanger is configured to receive a flow of main refrigerant from a main refrigerant adsorbent. A first main refrigerant expander has an inlet that is in fluid communication with the main refrigerant cooling passage and is configured to receive a first portion of the main refrigerant flowing through the main refrigerant cooling passage. The first main refrigerant expander has an outlet configured to guide the expanded main refrigerant to a first liquefied main refrigerant heating passage in a liquefied heat exchanger. The first main refrigerant expansion device has an inlet configured to receive a second portion of the main refrigerant from the first liquefier main refrigerant cooling passage, and an outlet that is in fluid communication with the second liquefier main refrigerant heating passage of the liquefier heat exchanger. The first pre-cooling main refrigerant heating passage of the first pre-cooling heat exchanger is configured to receive and heat the main refrigerant flow from the first liquefier main refrigerant heating passage. The second pre-cooling main refrigerant heating passage of the first pre-cooling heat exchanger is configured to receive and heat the secondary refrigerant flow from the second liquefier main refrigerant heating passage. The main refrigerant compression cooling system has a first inlet that is in fluid communication with the outlet of the first pre-cooling main refrigerant heating passage, and a second inlet that is in fluid communication with the outlet of the second pre-cooling main refrigerant heating passage. The main refrigerant compression cooling system also has an outlet configured to guide the main refrigerant to the inlet of the first main refrigerant pre-cooling passage in the first pre-cooling heat exchanger.

[0014]

[0014] The first pre-cooling heat exchanger includes a first cryogenic fluid pre-cooling passage configured to receive and cool a cryogenic supply gas flow. The second pre-cooling heat exchanger includes a second cryogenic fluid pre-cooling passage configured to receive and cool a cryogenic supply gas flow from the first cryogenic fluid pre-cooling passage. The pre-cooling adsorber has an inlet configured to receive the pre-cooled cryogenic fluid from the second cryogenic fluid pre-cooling passage of the second pre-cooling heat exchanger. The first cryogenic fluid cooling passage of the first liquefier heat exchanger is configured to fluidly communicate with the pre-cooling adsorber and cool the cryogenic fluid inside. The first liquefier adsorber is configured to receive the cryogenic fluid from the first cryogenic fluid cooling passage. The second cryogenic fluid cooling passage of the first liquefier heat exchanger is configured to receive and cool the cryogenic fluid from the first liquefier adsorber. The second liquefier adsorber is fluidly communicating with the second cryogenic fluid cooling passage. [Brief explanation of the drawing]

[0015] [Figure 1]

[0015] This is a schematic diagram of a first embodiment of the system of the present disclosure. [Figure 2]

[0016] This is a schematic diagram of a second embodiment of the system of the present disclosure. [Figure 3]

[0017] This is a schematic diagram of a third embodiment of the system of the present disclosure. [Modes for carrying out the invention]

[0016]

[0018] A more detailed description of the systems and methods described herein is given below. It should be understood that the following descriptions of specific systems and methods are intended to be illustrative and do not encompass all possible variations or applications. Therefore, the scope of this disclosure is not intended to be limiting and should be understood to include variations or embodiments that a person skilled in the art might conceive of.

[0017]

[0019] It should be noted that in this specification, lines, conduits, pipes, passages, and similar structures, as well as corresponding flows, may both be referred to by the same element number indicated in the figures.

[0018]

[0020] In the following explanation, the terms "gas" and "vapor" are used interchangeably.

[0019]

[0021] The term "heating passage" is used below in reference to a heat exchanger and refers to a passage through which the incoming fluid is heated. The term "cooling passage" is used below in reference to a heat exchanger and refers to a passage through which the incoming fluid is cooled.

[0020]

[0022] Reference numerals introduced in the specification in relation to the drawings may be repeated in one or more subsequent drawings for shared elements or components to illustrate other features without further explanation in the specification.

[0021]

[0023] In the claims, letters are used to identify the claimed steps (e.g., a, b, and c). These letters are used for reference purposes only when referring to method steps and are not intended to indicate the order in which the claimed steps are performed, unless the order is specifically stated in the claims, and only within that scope.

[0022]

[0024] Although the separator or separation device is shown as a drum in the figure, the separator or separation device referred to below may be, but not limited to, another type of vessel, a cyclone separator, a distillation unit, a coalescing separator, a mesh or vane type mist eliminator, or any other separation device known in the art. In addition, any type of mixer or splitter device known in the art may be used as the mixer or splitter referred to below.

[0023]

[0025] The embodiments described below refer to a system and method for cooling for a hydrogen gas liquefier, but the technology of the present disclosure may be used to perform cooling in an air separation process or system, or other types of processes or systems that require cooling by cryogenic fluids.

[0024]

[0026] According to an embodiment of the present disclosure, as described below, boiling a first cryogenic fluid such as liquid natural gas or nitrogen to precool a second cryogenic fluid such as nitrogen or hydrogen is improved when an ejector in which the first cryogenic fluid is used as a driving flow is added to the precooling loop, and with the help of the ejector, a portion of the first cryogenic fluid is depressurized and used to precool the second cryogenic fluid.

[0025]

[0027] Referring to FIG. 1, an embodiment of the system of the present disclosure is shown generally at 10. The precooling heat exchanger system includes a precooling heat exchanger 12 that includes a main heating passage 14 and a secondary heating passage 16 for a first cryogenic fluid that is LNG / natural gas in the illustrated embodiment. In addition, the precooling heat exchanger 12 includes a cooling passage 18 for a second cryogenic fluid that is nitrogen in the illustrated embodiment.

[0026]

[0028] The number of cooling and heating passages shown in the figure for the precooling heat exchanger 12 may be changed from that shown in FIG. 1, and the precooling heat exchanger system may take the form of a single heat exchanger (as shown in FIG. 1), or alternatively may take the form of a plurality of precooling heat exchangers.

[0027]

[0029] In the embodiment shown in FIG. 1, the first cryogenic fluid (LNG / natural gas) is used to precool the second cryogenic fluid (nitrogen), and the precooled second cryogenic fluid may be used to precool hydrogen gas before liquefying it in one or more downstream heat exchangers using a refrigerant such as hydrogen or helium.

[0028]

[0030] As is known in the art, the liquefaction of hydrogen may require additional components and / or processing steps such as purification (by adsorption systems, for example) and ortho-para conversion. Such components and processing steps are not illustrated or described herein, but are well known to those skilled in the art, and their implementation is not affected by the art of this disclosure.

[0029]

[0031] Continuing to refer to Figure 1, the LNG supply flow enters the system 10 at 24, flows into the mixer 26, and then flows into the splitter 32 as part of flow 28, where flow 28 is split into flow 34 and flow 36. As just one example, the splitter 32 may split approximately 90% of flow 28 into flow 34 and approximately 10% of flow 28 into flow 36.

[0030]

[0032] The flow 34 is guided to the ejector 40 as a driving flow.

[0031]

[0033] The flow 36 is directed to pass through an expansion device such as a Joule-Thomson (JT) valve 42, resulting in a partially condensed flow 44 with a lower boiling point. Instead of the JT valve 42, alternative types of expansion devices may be used, including alternative types of expansion valves, turbines, orifices, or any other types of expansion devices known in the art.

[0032]

[0034] The fluid 44 is led to a depressurized (e.g., below atmospheric pressure) separation device 46, where it is separated into a secondary vapor phase and a liquid phase. The vapor port of the separation device 46 leads the flow 48 through the mixer 52 to the suction port of the ejector 40. As a result, a suction force is generated at the vapor port of the separation device 46, and the pressure inside the separation device 46 decreases.

[0033]

[0035] The LNG flow 54 flows from the separation unit through the pre-cooling heat exchanger 12, where it is heated by heat transfer to the nitrogen flow that flows at least through the cooling passage 18. The LNG flow 54 is vaporized in the secondary heating passage 16, and the resulting natural gas flow 56 flows to the mixer 52, where it is mixed with the natural gas flow 48, and the mixed natural gas flow 58 is then accepted by the suction port of the ejector 40. As a result, an suction force is generated in the secondary heating passage 16 of the pre-cooling heat exchanger 12, causing the pressure to drop, which in turn lowers the pressure of the LNG flow 54, and consequently lowers its boiling point.

[0034]

[0036] The heating and vaporization of flow 54 removes some of the load on the nitrogen cycle, including the cooling passage 18 of the pre-cooling heat exchanger 12. As a result, the size of the compressor in the nitrogen cycle can be reduced, which can lower both the system equipment and energy costs.

[0035]

[0037] The driving LNG flow 34 is expanded and cooled, and as a result, the mixed-phase flow 62 exits the ejector 40 and moves to the main separation unit 64, where it is split into a natural gas flow 66 and an LNG recycling flow 68. The natural gas flow 66 is guided through the main heating passage 14 of the pre-cooled heat exchanger 12, where it is heated while cooling the nitrogen flow flowing through the passage 18. The resulting heated natural gas flow exits the system 10 as flow 72.

[0036]

[0038] After leaving the separation unit 64, the LNG recycled flow 68 is sent by the recycling pump 74 to form flow 76, which then merges with the LNG supply flow 24 in the mixer 26.

[0037]

[0039] The exemplary flow temperatures and pressures for the LNG and natural gas flows in the system shown in Figure 1 are shown in Table 1.

[0038] [Table 1]

[0039]

[0040] In an alternative embodiment of the present disclosure shown as 100 overall in Figure 2, the cooling of liquid natural gas is omitted, and the technique is used for pre-cooling a nitrogen flow, which can be used, for example, for pre-cooling a hydrogen gas flow for a hydrogen liquefaction system, or for pre-cooling an alternative cryogenic fluid in an alternative process. Referring more specifically to Figure 2, a first cryogenic fluid flow, such as a nitrogen supply flow, flows through an expansion device such as a JT valve 110, enters a mixer 112 as flow 114, and then flows into a main separator 116. The resulting nitrogen vapor flow 122 exits the top of the separator 116 for use as described below. As just one example, the main separator 116 may operate at atmospheric pressure.

[0040]

[0041] Instead of the JT valve 110, an alternative type of expansion device may be used, including an alternative type of expansion valve, turbine, orifice, or any other type of expansion device known in the art.

[0041]

[0042] The liquid nitrogen recycled flow 124 exits the bottom of the separation device 116 and is split by the splitter 126 into flow 128 and flow 130. For example, 90% of flow 124 may exit the splitter 126 as flow 128, and 10% of flow 124 may exit the splitter 126 as flow 130.

[0042]

[0043] Flow 128 is led to the main heating passage 129 of the first pre-cooling heat exchanger 132 of the pre-cooling heat exchanger system, where it is used to cool a second cryogenic fluid flow, which may be, for example, hydrogen gas flows 134a, 134b, and 134c flowing through the corresponding cooling passage of the heat exchanger 132. The resulting heated nitrogen gas flow 136 may exit the first pre-cooling heat exchanger 132 and be led to a mixer (not shown) to merge with flow 122. The resulting mixed flow can be led to a heating passage of a heat exchanger (not shown) to cool the hydrogen flow, and the resulting heated nitrogen flow is led to a JT valve, a series of compressors, and an aftercooler for regulation. The JT valve allows for the use of smaller and less expensive compressors, which in turn reduces the cost of system equipment and energy.

[0043]

[0044] After exiting splitter 126, the liquid nitrogen flow 130 is sent by recycle pump 142 to another splitter 146 as liquid nitrogen flow 144, where it is split into flow 152 and flow 154. As just one example, 90% of flow 144 exits splitter 146 as flow 152, while 10% of flow 144 exits splitter 146 as flow 154.

[0044]

[0045] The liquid nitrogen stream 154 is expanded through an expansion device such as a JT valve 156 to form a mixed-phase nitrogen stream 158 at a pressure of approximately half atmospheric pressure, as just one example, thereby lowering the boiling point of the stream 158 to approximately 70°K. The stream 158 is led to a secondary heating passage 160 of a second pre-cooling heat exchanger 162 of the pre-cooling heat exchanger system, where it is heated to lower the temperature of the hydrogen gas stream flowing through, for example, a cooling passage 164. This removes some load from the nitrogen cooling cycle and the downstream cooling cycle that further cools and liquefies the hydrogen flowing through the cooling passage 164. As a result, the size of the compressor in the downstream cooling cycle and any compressor (not shown) used in the nitrogen cooling cycle can be reduced, which can lower both the system equipment and energy costs.

[0045]

[0046] The nitrogen gas exits the heat exchanger 162 as flow 166 and is received by the suction port of the ejector 168. As a result, an attractive force is generated in the line through which flow 166 passes, causing the pressure in the secondary heating passage 160 of the second pre-cooling heat exchanger 162 to decrease in response to this pressure drop, and consequently the boiling point of the nitrogen flow 158 to decrease.

[0046]

[0047] Instead of the JT valve 156, an alternative type of expansion device may be used, including an alternative type of expansion valve, turbine, orifice, or any other type of expansion device known in the art.

[0047]

[0048] The number of cooling and heating passages shown in the figure for the first pre-cooling heat exchanger 132 and the second pre-cooling heat exchanger 162 may be changed from those shown in Figure 2, and the pre-cooling heat exchanger system may instead take the form of a single pre-cooling heat exchanger, or instead take the form of three or more pre-cooling heat exchangers.

[0048]

[0049] The liquid nitrogen flow 152 flows as the driving flow into the inlet of the ejector 168. The mixed phase flow 172 leaves the ejector 168 and moves to the mixer 112, where it merges with the nitrogen gas supply flow 110 and then flows as flow 174 to the main separator 116.

[0049]

[0050] The temperature and pressure of the exemplary nitrogen flow in the system shown in Figure 2 are shown in Table 2.

[0050] [Table 2]

[0051]

[0051] A third embodiment of the system of the present disclosure is shown as a whole in Figure 3 as 200 and is configured to liquefy a hydrogen gas supply stream 202 using nitrogen, natural gas, and hydrogen as refrigerants. Although the system is described in relation to the liquefaction of hydrogen gas, it may be used to liquefy different cryogenic gases instead. In this system, the ejector of the previous embodiment is omitted. Furthermore, as will be described in more detail below, the system of Figure 3 uses a Joule-Thomson (JT) valve for the nitrogen refrigerant cycle. In addition, as will be described further below, the system of Figure 3 uses a natural gas vacuum pump as part of the liquid natural gas cooling circuit.

[0052]

[0052] The system in Figure 3 features a pre-cooling cold box 204 and a liquefaction or liquefier cold box 206 for insulating the internally located components from the ambient temperature. The structure of such cold boxes is well known in the art. The pre-cooling cold box includes a first pre-cooling heat exchanger 210 and a second pre-cooling heat exchanger 212. As merely an example, the first and second pre-cooling heat exchangers may be brazed aluminum heat exchangers (BAHX). Although two pre-cooling heat exchangers are shown, there may be a single pre-cooling heat exchanger or three or more pre-cooling heat exchangers instead. The liquefaction cold box 206 includes a first liquefaction or liquefier heat exchanger 214 and a second liquefaction or liquefier heat exchanger 215. Although two liquefaction heat exchangers are shown in Figure 3, there may be one or three or more liquefaction heat exchangers instead.

[0053]

[0053] Nitrogen, natural gas, and hydrogen refrigerants pre-cool the hydrogen gas supply stream 202 in the pre-cooled cold box 204, while the hydrogen refrigerant stream cools the pre-cooled hydrogen gas supply stream in the liquefaction cold box 206.

[0054]

[0054] The flow of liquid natural gas (LNG) 216 is transferred to the first pre-cooling heat exchanger 210 using a pump 218. The LNG flow delivered by the pump is heated in the first LNG heating passage 222 of the heat exchanger 210 and then expanded by an expansion device 224 (which may be a JT valve as just one example). As just one example, the LNG flow 216 is supplied from one or more tanks at a temperature of -162°C (the boiling point of pure methane at atmospheric pressure), pressurized to a pressure of 1 MPa (10 bar) by the pump 218, and then preheated to -124.5°C and partially evaporated in the first LNG heating passage 222 of the first pre-cooling heat exchanger 210. The JT valve 224 then returns the flow temperature to -160°C with further evaporation.

[0055]

[0055] The mixed phase flow 226 exits the JT valve 224 and enters a subsequent separation device or phase separator 228, and the resulting steam flow 232 is led to the natural gas heating passage 234 of the first pre-cooling heat exchanger 210. The LNG flow 236 exits the phase separator 228 and is led to the JT valve (or other expansion device), and the resulting flow is led to the expansion fluid heating passage 242 of the first pre-cooling heat exchanger 210. A vacuum pump compressor 244, as just one example, allows the evaporation of the liquid in the passage 242 at 43 to 28 kPa (430 to 280 mbar) at -171°C. In some embodiments, this evaporation can remove a large portion of the heat load of the first pre-cooling heat exchanger 210. The vacuum compressor pressurizes the natural gas flow 246 exiting the passage 242 back to atmospheric pressure. The natural gas flow 250 exiting compressor 244 and the natural gas flow 252 exiting passage 234 merge to form flow 254, which then exits the system and is used further elsewhere.

[0056]

[0056] Additional cooling in the first and second pre-cooled heat exchangers in Figure 3, such as for the system adsorber shown below, may be performed by a liquid nitrogen cooling cycle. The nitrogen supply flow 256, which is at least partially liquid, is further cooled in the nitrogen cooling passage 258 of the first pre-cooled heat exchanger 210. The cooled flow is then expanded in the JT valve 262, and the resulting expanded flow is led to the separator 264. The liquid flow 266 exits the bottom of the separator 264 and is heated in the liquid nitrogen heating passage 270 of the second pre-cooled heat exchanger 212, where it cools. The resulting nitrogen vapor flow exits the passage 270 and merges with the nitrogen vapor flow 268 exiting the top of the separator 264. The merged nitrogen vapor flow then travels through the nitrogen vapor heating passage 272 of the first heat exchanger 210, where it is heated and cools. The resulting heated nitrogen vapor flow 274 exits passage 272, is compressed in a first nitrogen compressor 276, subsequently cooled in a first nitrogen aftercooler 278, further compressed in a second nitrogen compressor 280, and then finally cooled in a second nitrogen aftercooler 282. As a result, a nitrogen supply flow 256 is formed. As a mere example, compressors 280 and 282 may be screw compressors. In alternative embodiments, single-stage or three-stage or more nitrogen compressors and aftercoolers may be used. Furthermore, in alternative embodiments, the JT valve 262 may be replaced by a different expansion device such as a compander.

[0057]

[0057] In the first liquefied heat exchanger 214 and the second liquefied heat exchanger 215, cooling is performed by the main refrigerant containing hydrogen in the main refrigeration circuit. In addition, the first and second pre-cooling heat exchangers are further cooled by the main refrigerant circuit.

[0058]

[0058] In the main refrigeration circuit, the hydrogen refrigerant flow 292 flows through the first main refrigerant pre-cooling passage 294 of the first pre-cooling heat exchanger 210 and the second main refrigerant pre-cooling passage 296 of the second pre-cooling heat exchanger 212, where it is cooled by the nitrogen and LNG / NG refrigeration circuits described above. The cooled hydrogen fluid flow exiting passage 296 then moves through the adsorber 298 and exits the pre-cooled cold box 204 as flow 302. The continuously circulating refrigerant has a low risk of carrying / taking in contaminants. For this reason, it is possible to operate the system without adsorbers during the short period of adsorber regeneration.

[0059]

[0059] The flow 302 enters the liquefier cold box 206 and is further cooled in the main refrigerant cooling passage 304 of the liquefier heat exchanger 214. The first main refrigerant branch pipe 306 directs a portion of the hydrogen refrigerant flow 302 to the first main refrigerant expander 308a and the second main refrigerant expander 308b, and the resulting expanded flow 312 is directed back to the first main refrigerant heating passage 314 of the first liquefier heat exchanger 214. The remaining portion of the flow 302 is directed to pass through further portions of the main refrigerant cooling passage 304 for further cooling. The second main refrigerant branch pipe 316 directs a portion of the hydrogen refrigerant flow to the third main refrigerant expander 318, and the resulting expanded flow 322 is directed back to the first main refrigerant heating passage 314 of the first liquefier heat exchanger 214. The hydrogen refrigerant is heated in the main refrigerant heating passage of the first liquefier heat exchanger 214, and refrigeration takes place within it.

[0060]

[0060] Figure 3 shows expansion turbines 308a, 308b, and 318, but instead, a single turbine flow path or additional turbine flow paths with heat exchanger flow paths in between may be used. In addition, instead of turbines, alternative types of expansion devices including, but not limited to, expansion valves may be used.

[0061]

[0061] The hydrogen refrigerant remaining in the main refrigerant cooling passage 304 after the branch pipes 306 and 316 is further cooled and exits the passage 304 as flow 324, which is then expanded by the JT valve 326 (or any other type of expansion device), and the resulting expanded flow is led to the separator 328. The vapor flow 332 exits the separator 328 and is led through the second main refrigerant heating passage 334, where it undergoes further cooling in the liquefier heat exchanger 214. The liquid hydrogen refrigerant flow 336 exits the separator 328 and enters the liquid hydrogen heating passage 338 of the second liquefier heat exchanger 215, where it undergoes cooling. The resulting at least partially vaporized hydrogen refrigerant flow exits the passage 338 and is led to the separator 328.

[0062]

[0062] Flows 312, 322, and 332 work together to perform the necessary refrigeration for liquefying the pre-cooled hydrogen flow 202 in the liquefier cold box 206. For example, the temperature of the hydrogen gas flow 202 can be lowered to about 20°K to 22°K at the low-temperature end of the liquefier cold box 206.

[0063]

[0063] The flow 342 exiting the first main refrigerant heating passage 314 of the first liquefier heat exchanger 214, and the flow 344 exiting the second main refrigerant heating passage 334, are guided to pass through the first pre-cooling hydrogen heating passage 346 and the second pre-cooling hydrogen heating passage 348 of the first pre-cooling heat exchanger 210, where part of the refrigeration takes place. The resulting hydrogen gas flows 352 and 354 exit the pre-cooling cold box 204.

[0064]

[0064] The hydrogen refrigerant vapor flow 354 travels through the first main compressor 356, the first main aftercooler 358, the second main compressor 362, and the second main aftercooler 364 of the main refrigeration circuit to form an intermediate-pressure vapor flow 366. The hydrogen refrigerant vapor flow 352 merges with the intermediate-pressure vapor flow 366 to form a mixed hydrogen refrigerant vapor flow 368, which is guided to pass through the third main compressor 372, the third main aftercooler 374, the fourth main compressor 376, and the fourth main aftercooler 378 to form a high-pressure hydrogen refrigerant flow 292. A portion of the hydrogen refrigerant flow 292 can be introduced into the hydrogen vapor supply flow 202 by operating the valve 382 to perform initial cooling of the flow 202.

[0065]

[0065] As shown in Figure 3, the gaseous hydrogen supply flow 202 enters the pre-cooled cold box 204 and passes through the first hydrogen pre-cooling passage 392 of the first pre-cooled heat exchanger 210 and the second hydrogen pre-cooling passage 394 of the second pre-cooled heat exchanger 212, where it is cooled as will be described in more detail below. The cooled flow 396 then passes through the adsorbers 398a, 398b, and 402. The adsorbers function to remove any type of impurities from the hydrogen fluid flow. The adsorbers include a specific material to which impurities are bound or absorbed. In one embodiment, the adsorbers may be made of carbon, specifically activated carbon material, but zeolites may also be used.

[0066]

[0066] The purified hydrogen gas stream that exits the adsorber 402 then travels again through the third hydrogen pre-cooling passage 404 of the second pre-cooling heat exchanger 212 as a second flow path, where it is further cooled to (just as an example) about 80°K or below.

[0067]

[0067] The cooled flow 405 of the second channel then enters the liquefier cold box 206 and flows through the first hydrogen liquefier cooling passage 406 of the first liquefier heat exchanger 214. The resulting cooled hydrogen flow flows through the first liquefier adsorber 408, which directs the outgoing hydrogen flow to the second hydrogen liquefier cooling passage 412. The further cooled hydrogen flow that exits passage 412 is directed to the second liquefier adsorber 414, which directs the outgoing hydrogen flow to the third hydrogen liquefier cooling passage 416. The fully or partially liquefied hydrogen flow that exits passage 416 moves to the third liquefier adsorber 418. The hydrogen flow exiting the third liquefier adsorber 418 is further cooled or subcooled in the fourth hydrogen liquefier cooling passage 422, which is cooled by the second liquefier heat exchanger 215, and the resulting liquid hydrogen flow 424 moves to the hydrogen storage container 426. The line carrying the flow 424 may optionally include a JT valve 428 (or other product expansion device) for cooling the flow. Steam from both the hydrogen storage container 426 and the tank truck 432 is discharged through the vent line 434.

[0068]

[0068] The hydrogen pre-cooling passages of the first pre-cooling heat exchanger 210 and the second pre-cooling heat exchanger 212, and / or the hydrogen liquefier cooling passages of the first liquefier heat exchanger 214 and / or the second liquefier heat exchanger 215 may include an ortho-para conversion catalyst that converts ortho-hydrogen to para-hydrogen to reduce volatilization. Such a conversion catalyst may instead be placed in one of the adsorbers or in a standalone device.

[0069]

[0069] As mentioned above, the number of heat exchangers and adsorbents shown in the figure may be changed from those shown in Figure 3.

[0070]

[0070] Preferred embodiments of the present disclosure have been shown and described, but it will be apparent to those skilled in the art that the scope may be modified and altered without departing from the spirit of the present disclosure as defined by the following claims.

Claims

1. A system for pre-cooling a second cryogenic fluid using a first cryogenic fluid, a. A pre-cooling heat exchanger system comprising a main heating passage, a secondary heating passage, and at least one cooling passage, wherein the main heating passage is configured to receive a flow of a first cryogenic fluid to heat a second cryogenic fluid in the at least one cooling passage, b. A first splitter configured to receive a first cryogenic fluid flow and to split the first cryogenic fluid flow into a drive flow and a secondary cooling flow, c. An ejector having an ejector inlet, an ejector outlet, and a suction port, wherein the ejector inlet is configured to receive the drive flow from the first splitter, d. An expansion device configured to receive and expand the secondary cooling flow from the first splitter, and to guide at least a portion of the expanded secondary cooling flow into the secondary heating passage of the pre-cooled heat exchanger system, thereby cooling the second cryogenic fluid in at least one cooling passage of the heat exchanger system. e. The secondary heating passage of the pre-cooling heat exchanger system, which is in fluid communication with the suction port of the ejector, and as a result, the first cryogenic fluid from the secondary heating passage is guided to the suction port of the ejector, and the pressure in the secondary heating passage decreases. f. A main separation device having a main separation device inlet, a main separation device steam outlet, and a main separation device liquid outlet, wherein the main separation device inlet is in fluid communication with the ejector outlet, and the main separation device divides a first cryogenic fluid mixed phase flow into a first cryogenic fluid vapor flow that exits the main separation device through the main separation device steam outlet and a liquid recycling flow that exits the main separation device through the main separation device liquid outlet, g. A recycling pump having a pump inlet that is in fluid communication with the liquid outlet of the main separator, and a pump outlet configured to guide the first cryogenic fluid to the first splitter. A system equipped with these features.

2. The system according to claim 1, wherein the main heating passage of the heat exchanger system is configured to be in fluid communication with the steam outlet of the main separator and to receive and heat the steam flow from the main separator, thereby cooling the second cryogenic fluid in at least one cooling passage of the heat exchanger system.

3. The system according to claim 1, further comprising a second splitter configured to receive the liquid recycle flow from the liquid outlet of the main separator and to divide the liquid recycle flow into a first portion and a second portion to be received by the recycle pump, wherein the main heating passage of the heat exchanger system is configured to receive and heat the second portion of the liquid recycle flow, thereby cooling a second cryogenic fluid in the at least one cooling passage of the heat exchanger system.

4. The system according to claim 1, further comprising a first mixer configured to receive a liquid recycle flow from the recycle pump and a first cryogenic liquid supply flow, thereby forming a mixed first cryogenic liquid flow which is led to the first splitter.

5. The system according to claim 1, wherein at least one cooling passage is a single cooling passage, and the pre-cooling heat exchanger system includes a single pre-cooling heat exchanger comprising the main heating passage, the secondary heating passage, and the single cooling passage.

6. The system according to claim 1, wherein at least one cooling passage includes a first cooling passage and a second cooling passage, and the pre-cooling heat exchanger system includes a first pre-cooling heat exchanger including the main heating passage and the first cooling passage, and a second pre-cooling heat exchanger including the secondary heating passage and the second cooling passage.

7. The system according to claim 1, wherein the first cryogenic fluid contains liquid natural gas and the second cryogenic fluid contains nitrogen.

8. The system according to claim 1, wherein the first cryogenic fluid contains nitrogen and the second cryogenic fluid contains hydrogen.

9. The system according to claim 1, wherein the expansion device is a Joule-Thomson valve.

10. The system according to claim 1, wherein the main separation device is configured to operate at atmospheric pressure.

11. The system according to claim 10, further comprising a vacuum separator and a third mixer, wherein the vacuum separator is configured to receive the expanded secondary cooling flow from the expansion device and separate the expanded secondary cooling flow into a secondary liquid flow and a secondary vapor flow, the secondary liquid flow being led to the secondary heating passage of the pre-cooling heat exchanger system, the secondary vapor flow being led to the third mixer, the third mixer being configured to also receive the heated first cryogenic fluid from the secondary heating passage of the pre-cooling heat exchanger system and to lead the resulting mixed flow to the suction port of the ejector.

12. The system according to claim 1, further comprising a second mixer configured to receive a first cryogenic fluid mixed phase flow and a first cryogenic liquid supply flow from the ejector outlet, thereby forming a mixed first cryogenic liquid flow which is then led to the main separator.

13. A method for pre-cooling a second cryogenic fluid using a first cryogenic fluid, a. A step of dividing the first cryogenic fluid flow into a driving flow and a secondary cooling flow, b. The step of guiding the drive flow to an ejector having a suction port, c. The step of expanding the secondary cooling flow, d. A step of cooling a second cryogenic fluid using at least a portion of the expanding secondary cooling flow, wherein a heated first cryogenic fluid is formed as a result. e. The step of guiding the heated first cryogenic body to the suction port of the ejector, f. A step of separating the first cryogenic fluid mixed phase flow from the outlet of the ejector into a vapor flow and a liquid recycle flow, g. Step a, pumping at least a portion of the liquid recycle flow for use as the first cryogenic fluid flow. A method that includes this.

14. The method according to claim 13, wherein the first cryogenic fluid contains liquid natural gas and the second cryogenic fluid contains nitrogen.

15. The method according to claim 13, wherein the first cryogenic fluid contains nitrogen and the second cryogenic fluid contains hydrogen.

16. The method according to claim 13, wherein the expansion in step c is achieved using a Joule-Thomson valve.

17. The method according to claim 13, wherein the vapor flow in step f is heated to cool the second cryogenic fluid flow.

18. The method according to claim 13, further comprising the step of mixing the liquid recycling flow delivered by the pump in step g with the first cryogenic liquid supply flow to form the first cryogenic fluid flow in step a.

19. The method according to claim 13, wherein a portion of the liquid recycling flow in step f is heated to cool the second cryogenic fluid flow.

20. The method according to claim 13, further comprising the step of mixing the first cryogenic fluid mixed phase flow from the outlet of the ejector with the first cryogenic fluid before the separation of step f.

21. A system for liquefying cryogenic gas supply streams, a. The first pre-cooling heat exchanger, b. A second pre-cooling heat exchanger, c. Liquefied heat exchanger and d. A natural gas pre-cooling refrigeration circuit, i) A liquid natural gas heating passage of the first pre-cooling heat exchanger configured to receive and heat a liquid natural gas supply flow, ii) A first pre-cooling expansion device configured to receive the fluid flow from the liquid natural gas heating passage of the first pre-cooling heat exchanger, iii) A first pre-cooling separation device having a first pre-cooling separation device steam outlet configured to guide a fluid to the inlet of the natural gas heating passage of the first pre-cooling heat exchanger, the first pre-cooling separation device also having a first pre-cooling separation device liquid outlet, configured to receive and separate a fluid flow from the first pre-cooling expansion device, such that a natural gas vapor flow exits the first pre-cooling separation device steam outlet and a liquid natural gas flow exits the first pre-cooling separation device liquid outlet, iv) A second pre-cooling expansion device configured to receive the liquid natural gas flow from the liquid outlet of the first pre-cooling separation device and guide the expanding fluid flow to the inlet of the expanding fluid heating passage of the first pre-cooling heat exchanger, v) A first pre-cooling compressor having an inlet that is in fluid communication with the outlet of the expansion fluid heating passage of the first pre-cooling heat exchanger, in order to reduce the pressure in the expansion fluid heating passage. A natural gas pre-cooling refrigeration circuit including, e. A nitrogen pre-cooling refrigeration circuit, i) The nitrogen cooling passage of the first heat exchanger, ii) A third pre-cooling and expansion device configured to receive and expand the fluid flow from the nitrogen cooling passage of the first heat exchanger, iii) A second pre-cooling separator having an inlet configured to receive an expanding fluid from the third pre-cooling separator, a second pre-cooling separator vapor outlet, and a second pre-cooling separator liquid outlet, wherein the second pre-cooling separator is configured to receive and separate a fluid flow from the third pre-cooling expansion unit, so that a nitrogen vapor flow exits the second pre-cooling separator vapor outlet and a liquid nitrogen flow exits the second pre-cooling separator liquid outlet, iv) The second pre-cooling heat exchanger having a liquid nitrogen heating passage configured to receive and heat a liquid nitrogen flow from the liquid outlet of the second pre-cooling separation device, v) The first pre-cooling heat exchanger having a nitrogen vapor heating passage having an outlet for the liquid nitrogen heating passage of the second pre-cooling heat exchanger and an inlet that is in fluid communication with the vapor outlet of the second pre-cooling separation device, vi) A nitrogen compression cooling system having an inlet that is in fluid communication with the outlet of the nitrogen vapor heating passage, and an outlet that is in fluid communication with the nitrogen cooling passage of the first heat exchanger. A nitrogen pre-cooling refrigeration circuit equipped with, f. The main refrigeration circuit, i) A first main refrigerant pre-cooling passage in the first pre-cooling heat exchanger and a second main refrigerant pre-cooling passage in the second pre-cooling heat exchanger, each configured to receive and pre-cool the flow of the main refrigerant, ii) A main refrigerant adsorbent configured to receive a pre-cooled main refrigerant flow from the second main refrigerant pre-cooling passage of the second pre-cooling heat exchanger, iii) A liquefied main refrigerant cooling passage of the liquefied heat exchanger configured to receive the main refrigerant flow from the main refrigerant adsorbent, iv) A first main refrigerant expander having an inlet that is in fluid communication with the main refrigerant cooling passage and configured to receive a first portion of the main refrigerant flowing through the main refrigerant cooling passage, the first main refrigerant expander having an outlet configured to guide the expanded main refrigerant to a first liquefier main refrigerant heating passage of the liquefier heat exchanger, v) A first main refrigerant expansion device having an inlet configured to receive a second portion of the main refrigerant from the first main refrigerant cooling passage of the liquefier, and an outlet that is in fluid communication with the second main refrigerant heating passage of the liquefier heat exchanger, vi) A first pre-cooling main refrigerant heating passage of the first pre-cooling heat exchanger configured to receive and heat the main refrigerant flow from the first liquefier main refrigerant heating passage, and a second pre-cooling main refrigerant heating passage of the first pre-cooling heat exchanger configured to receive and heat the secondary refrigerant flow from the second liquefier main refrigerant heating passage, vii) A main refrigerant compression cooling system having a first inlet that is in fluid communication with the outlet of the first pre-cooling main refrigerant heating passage, a second inlet that is in fluid communication with the outlet of the second pre-cooling main refrigerant heating passage, and an outlet configured to guide the main refrigerant to the inlet of the first main refrigerant pre-cooling passage in the first pre-cooling heat exchanger. The main refrigeration circuit includes, g. A first pre-cooling heat exchanger comprising a first cryogenic fluid pre-cooling passage configured to receive and cool a cryogenic supply gas flow, and a second pre-cooling heat exchanger comprising a second cryogenic fluid pre-cooling passage configured to receive and cool a cryogenic supply gas flow from the first cryogenic fluid pre-cooling passage, h. A pre-cooling adsorbent having an inlet configured to receive the pre-cooled cryogenic fluid from the second cryogenic fluid pre-cooling passage of the second pre-cooling heat exchanger, i. The first cryogenic fluid cooling passage of the first liquefier heat exchanger, which is configured to communicate with the pre-cooled adsorbent and cool the cryogenic fluid inside, j. A first liquefier adsorbent configured to receive cryogenic fluid from the first cryogenic fluid cooling passage, k. A second cryogenic fluid cooling passage of the first liquefier heat exchanger, configured to receive and cool the cryogenic fluid from the first liquefier adsorbent, l. The second cryogenic fluid cooling passage and the second liquefier adsorbent that are in fluid communication with each other A system equipped with these features.

22. The system according to claim 21, further comprising a pre-cooling cold box in which the pre-cooling heat exchanger is disposed inside, and a liquefaction cold box in which the liquefaction heat exchanger is disposed inside.

23. The system according to claim 21, wherein the first pre-cooling expansion device, the second pre-cooling expansion device, the third pre-cooling expansion device, and the first main refrigerant expansion device are Joule-Thomson valves.

24. The system according to claim 21, wherein the main refrigerant is hydrogen.

25. The system according to claim 21, m. A liquefier main refrigerant separation device having a first inlet configured to receive the main refrigerant flow from the first main refrigerant expansion device, and an outlet that is in fluid communication with the second liquefier main refrigerant heating passage of the liquefier heat exchanger, n. A second liquefier heat exchanger having a liquid main refrigerant heating passage and a cryogenic fluid cooling passage, wherein the liquid main refrigerant heating passage is configured to receive and heat a liquid main refrigerant flow from the liquefier main refrigerant separation device, and the cryogenic fluid cooling passage is configured to receive and cool a cryogenic fluid flow from the second liquefier adsorbent, o. The main refrigerant heating passage of the second liquefier heat exchanger, which is configured to guide the heated main refrigerant to the second inlet of the liquefier main refrigerant separation device, A system that further enhances this feature.

26. The system according to claim 25, p. A product expansion device configured to receive and expand the cryogenic fluid from the cryogenic fluid cooling passage of the second liquefier heat exchanger, q. A cryogenic liquid storage container configured to receive the flow of cryogenic liquid from the product expansion device, A system that further enhances this feature.

27. The system according to claim 26, wherein the product expansion device is a Joule-Thomson valve.

28. The system according to claim 21, wherein the cryogenic supply gas flow is hydrogen gas.

29. The system according to claim 21, further comprising a branch valve having an inlet that is in fluid communication with the outlet of the main refrigerant compression cooling system and an outlet that is in fluid communication with the inlet of the first cryogenic fluid pre-cooling passage, thereby enabling selective guidance of a portion of the main refrigerant to the first cryogenic fluid pre-cooling passage of the first pre-cooling heat exchanger.

30. The system according to claim 21, further comprising a liquid natural gas pump configured to supply liquefied natural gas to the liquid natural gas heating passage of the first pre-cooling heat exchanger.

31. The system according to claim 21, wherein the first main refrigerant expander is a turbine.

32. The system according to claim 21, wherein each of the nitrogen compression cooling system and the main refrigerant compression cooling system includes a compressor and a plurality of stages of an aftercooler.

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