Apparatus and process for limiting thermal stresses of a heat exchanger

Abstract

An apparatus for a heat exchanger can include a mechanism or flow control process arrangement that can be configured to maintain a temperature profile of internal components of the heat exchanger within a preselected temperature range during a non-operational cycle of a plant process or facility to help reduce thermal stresses induced by the heat exchanger and its internal components. Embodiments of heat exchanger apparatus and heat exchanger operation processes can facilitate maintaining a preselected temperature profile in the heat exchanger during a non-operational or non-use cycle and also facilitate faster start-up operations when the plant process is to resume with the heat exchanger in operation.

Description

Technical Field

[0001] This invention relates to heat exchanger-related processes and equipment. Background Technology

[0002] Heat exchangers can be used in various processes to facilitate the cooling and heating of different process fluids. Examples of heat exchangers and heat exchange processes used in different types of industrial applications can be found in international publications WO 2021 / 037391 and WO2020 / 200521, as well as European publication EP4246070A1 and Japanese publication JP2022156743A. Summary of the Invention

[0003] In cryogenic applications, heat exchangers used to cool compressed gas feedstocks can have a warm end relatively close to ambient temperature (e.g., between 0°C and 40°C) and a cold end that can be within a cryogenic temperature range (e.g., for supplying air to air separation units, etc.). For example, the cold end of the heat exchanger can be in a temperature range of -150°C to -195°C. The middle section of the heat exchanger can be at different temperatures between the cold and warm ends (e.g., fluid transferred from the warm end to the cold end gradually cools as it moves to the colder end, and fluid transferred from the cold end to the warm end gradually warms as it moves to the warmer end). Such heat exchangers can be brazed aluminum heat exchangers (BAHX). Large cryogenic plants can combine several BAHXs together.

[0004] When a heat exchanger is not in use, processes including heat leakage and heat conduction can cause internal components of the heat exchanger to move to temperatures different from those during normal operation, such as average or ambient temperatures. In many operational conditions, for example, the average or ambient temperature can differ significantly from the temperature of the internal components of the heat exchanger during normal operation. This can generate thermal stress on the components of the heat exchanger. For example, thermal expansion or contraction that may occur when the temperature profile of the heat exchanger changes can lead to significant thermal stress on the components of the heat exchanger. This type of stress may occur when a plant liquefier is restarted after the heat exchanger's temperature profile has been allowed to deviate significantly from its operational profile (e.g., after a significant period of inactivity between plant shutdown and plant restart).

[0005] In cyclic operation, this thermal stress effect can combine with stress attributable to pressure cycling to generate total cyclic stress on the equipment. In typical operational configurations for conventional plants, such operational conditions for heat exchangers may occur only infrequently, making the cyclic stress unlikely to be considered problematic in any way. However, it has been determined that this type of cyclic stress can be a significant problem when the heat exchanger is expected to be used in processes that may involve multiple shutdowns and openings within a day, week, or month. In such operational conditions, cyclic stress events may occur hundreds of times per year, compared to only 0 to 5 times per year in non-cyclic operation. This more frequent occurrence of cyclic stress can lead to fatigue failure of internal components of the heat exchanger, potentially requiring extensive repair or replacement work on the heat exchanger equipment and resulting in extended facility downtime to address unforeseen problems.

[0006] To help address these issues, embodiments of processes for operating heat exchangers, heat exchanger equipment, and methods of their manufacture and use have been developed that can help avoid or limit the thermal stress that heat exchangers may experience when a plant is shut down or inoperable relatively frequently (e.g., daily, multiple times a week, etc.). Such embodiments can facilitate maintaining the temperature profile of the heat exchanger to a preselected temperature profile by utilizing a single fluid flow or a minimal number of fluid flows, providing the heat transfer that may be required to maintain the temperature profile to a preselected temperature range or within a preselected profile when the plant's liquefiers are inoperable. Embodiments can help minimize the thermal stress experienced by the heat exchanger and also enable faster restarting of the heat exchanger to support operation. Embodiments can also be provided in a way that requires relatively little additional equipment for implementation. These types of features can allow for more flexible operating methods, which can also reduce maintenance costs and help extend the life of the heat exchanger equipment. Embodiments can also be configured to help allow variable plant operation due to fluctuations in electricity prices, weather conditions that may affect the availability of renewable electricity for power supply operations, and / or other operational conditions, resulting in improved efficiency, reduced costs, and / or reduced environmental impact.

[0007] In some embodiments, the heat exchanger device may be used in conjunction with a high-temperature process, and the temperature profile of the heat exchanger may be maintained to a preselected temperature profile by using a single fluid flow or a minimum number of fluid flows (to provide the heat transfer that may be needed to maintain the temperature profile when the plant or process unit of the plant is not operational, to maintain the temperature profile of the heat exchanger to a preselected temperature range or preselected profile) at a temperature higher than the ambient temperature (e.g., a relatively hot temperature).

[0008] In other embodiments, the heat exchanger device can be used in conjunction with significantly low temperatures (e.g., cryogenic temperature ranges). Maintaining the temperature profile of the heat exchanger to a preselected temperature profile using a single fluid flow or a minimum number of fluid flows (to provide the heat transfer that may be needed to maintain the temperature profile when the plant or a process unit (e.g., a liquefier) ​​is inoperable) can be a temperature below ambient temperature (e.g., a relatively cold temperature or a temperature at or near a cryogenic temperature range).

[0009] For example, in some embodiments, the heat exchanger device may be used in conjunction with an air separation unit (ASU) to produce nitrogen, oxygen, and / or argon. Other embodiments may combine the heat exchanger with other types of ASU systems or other types of industrial processes or plants, such as, for example, liquefaction units or liquefaction plants (e.g., liquefaction plants for liquefying gases such as hydrogen, oxygen, natural gas, nitrogen, argon, or air) or other types of plants utilizing cryogenic fluids or cryogenic operating conditions.

[0010] In a first aspect, a process for operating a heat exchanger device may be provided. Embodiments of this process may include supplying at least a first feed fluid to the heat exchanger device and at least a first refrigerant fluid to the heat exchanger device, while a plant process is operable to cool the first feed fluid and heat the first refrigerant fluid. In response to shutdown of the plant process, the supply of the first feed fluid to the heat exchanger device and the supply of the first refrigerant fluid to the heat exchanger device may be stopped, and at least one process flow may be supplied to the heat exchanger device to maintain the temperature profile of the heat exchanger device when the plant process is shut down.

[0011] In some embodiments, the process flow supplied to the heat exchanger device to maintain the temperature profile of the heat exchanger device may pass through the heat exchanger device and then be recirculated back to the heat exchanger device to simulate heat transfer that occurs when the first feed fluid is cooled by the first refrigerant fluid. In other embodiments, the process flow may pass through the heat exchanger device in a single pass to maintain the temperature profile of the heat exchanger device.

[0012] In the second aspect, at least one process flow may include evaporated vapor or separator evaporated vapor of a cryogenic liquid fluid stored in at least one storage tank.

[0013] In a third aspect, the process may also include other steps. For example, the process may also include outputting at least one process stream from a heat exchanger device when the liquefier in the plant process is deactivated, and recycling the output at least one process stream back to the heat exchanger device. As another example, the process may include outputting at least one process stream from a heat exchanger device when the liquefier in the plant process is deactivated, heating the at least one process stream after it has been output from the heat exchanger device, and recycling the output at least one process stream back to the heat exchanger device as at least one recirculated process stream. In some embodiments, the process may also include outputting at least one recirculated process stream from the heat exchanger device to discharge the recirculated process stream.

[0014] In some embodiments, the recirculated process gas may have a temperature between 0°C and 50°C when it is returned to the heat exchanger device. In other embodiments, the recirculated process gas may have another suitable temperature.

[0015] In the fourth aspect, at least one process flow may include a refrigerant process flow at a temperature between -150°C and -200°C. In other embodiments, the process flow may be at another suitable temperature.

[0016] In the fifth aspect, the first feed fluid may consist of nitrogen and / or oxygen. For example, the first feed fluid may be air, may include air, may include a stream primarily composed of nitrogen, may include a stream comprising a large amount of nitrogen and oxygen, may include a stream comprising a large amount of oxygen, or may be a stream primarily composed of oxygen or primarily composed of nitrogen.

[0017] In a sixth aspect, the first feed fluid can be at a temperature between 0°C and 50°C, and the first refrigerant fluid can be at a temperature between -150°C and -200°C. In other embodiments, the feed and refrigerant fluids can be at different temperatures.

[0018] In a seventh aspect, the process may also include a regulating valve to supply at least one process stream to a heat exchanger device to maintain the temperature profile of the heat exchanger device when the liquefier in the plant process is shut down. In some embodiments, the at least one process stream may include evaporated vapor of a cryogenic liquid fluid stored in at least one storage tank, a stream output from the tower assembly of an air separation unit (ASU), and / or separator evaporated gas.

[0019] In the eighth aspect, the process of the first aspect may include one or more other features or elements. For example, the process of the first aspect may include one or more features of the second, third, fourth, fifth, sixth, and / or seventh aspects. Embodiments may also include other features or elements. For example, examples of other features or elements can be understood from exemplary embodiments of the processes discussed herein.

[0020] In a ninth aspect, a heat exchanger apparatus is provided. Some embodiments of the heat exchanger apparatus can be configured to implement embodiments of a process for operating the heat exchanger apparatus. Embodiments of the heat exchanger apparatus may include a first heat exchanger fluidly connected to at least a first warm fluid feed line and a first refrigerant feed line, such that refrigerant can be supplied to the heat exchanger apparatus via the first refrigerant feed line to cool the feed fluid supplied to the heat exchanger apparatus via the first warm fluid feed line when the plant process utilizing the heat exchanger apparatus is operable. The heat exchanger apparatus may also include a recirculation piping arrangement positioned to recirculate the process flow delivered to the first heat exchanger via the first refrigerant feed line when the plant process is shut down, to maintain the temperature profile of the heat exchanger apparatus when the plant process is shut down.

[0021] In a tenth aspect, the recirculation piping arrangement includes a temperature difference control device. In some embodiments, the temperature difference control device may be a heating device (e.g., an electric heater or other type of heating device). In other embodiments, the temperature difference control device may be a cooling device (e.g., a freezer, a refrigeration unit, etc.).

[0022] In the eleventh aspect, the plant process utilizing the heat exchanger equipment may be liquefied via a liquefaction device, and the first refrigerant feed pipe may be fluidly connected to the liquefaction device's liquefaction unit.

[0023] In a twelfth aspect, the heat exchanger apparatus may include a storage tank configured to store a cryogenic liquid. The storage tank may be fluidly connected to a first heat exchanger such that vapors from the cryogenic liquid can be supplied to the first heat exchanger as a process flow. In some embodiments, the storage tank may be fluidly connected to the first heat exchanger via a first refrigerant feed line such that vapors from the cryogenic liquid can be supplied to the first heat exchanger as, for example, a process flow.

[0024] In a thirteenth aspect, the heat exchanger apparatus may include a separator fluidly connected to the first heat exchanger, such that separator evaporated gas from the separator may be supplied to the first heat exchanger as a process flow. In some embodiments, the separator may be fluidly connected to the first heat exchanger via a first refrigerant feed line, such that separator evaporated gas from the separator may be supplied to the first heat exchanger as, for example, a process flow.

[0025] In a fourteenth aspect, the heat exchanger device may include a tower assembly of an air separation unit (ASU) that is fluidly connected to a first heat exchanger, such that a flow exiting the tower assembly may be passed to the first heat exchanger as a process flow. In some embodiments, the tower assembly may be fluidly connected to the first heat exchanger via a first refrigerant feed line, such that a flow exiting the tower assembly may be passed to the first heat exchanger as, for example, a process flow.

[0026] In the fifteenth aspect, the heat exchanger device of the ninth aspect may include one or more features of the tenth, eleventh, twelfth, thirteenth, and / or fourteenth aspects. Embodiments may also include other features or elements. For example, examples of other features or elements can be understood from exemplary embodiments of the heat exchanger device discussed herein.

[0027] In a sixteenth aspect, a plant is provided. The plant may include a liquefaction unit comprising at least one liquefier and a heat exchanger unit located upstream of the at least one liquefier. The heat exchanger unit may be positioned to liquefy a feed to be supplied to the at least one liquefier via at least one refrigerant output from the at least one liquefier during operation of the liquefaction unit. The heat exchanger unit may include a recirculation piping arrangement positioned and configured such that a process flow can be supplied to the heat exchanger unit to maintain a temperature profile of the heat exchanger unit when the liquefaction unit is shut down. The recirculation piping arrangement may include a differential temperature control device such that a process flow can be output from the heat exchanger unit, its temperature regulated by the differential temperature control device, and subsequently recirculated to the heat exchanger unit.

[0028] In the seventeenth aspect, the temperature difference control device can be configured such that a process flow can be output from a heat exchanger device, its temperature regulated by the temperature difference control device, and subsequently recirculated to the heat exchanger device to simulate heat transfer occurring to cool the feed to be supplied to at least one liquefier via at least one refrigerant output from at least one liquefier. In some embodiments, the temperature difference control device can be configured as a heating device or a cooling device.

[0029] In the eighteenth aspect, the plant can be configured to implement embodiments of processes for operating heat exchanger equipment. The plant may also include embodiments of the heat exchanger equipment described in the ninth, tenth, eleventh, twelfth, thirteenth, fourteenth, or fifteenth aspects.

[0030] It should be understood that embodiments of processes, plants, and equipment can utilize a variety of piping arrangements and process control elements. Embodiments may utilize sensors (e.g., pressure sensors, temperature sensors, flow rate sensors, concentration sensors, etc.), controllers, valves, piping, and other process control elements. For example, some embodiments may utilize automated process control systems and / or distributed control systems (DCS). A variety of different piping configurations and process control systems can be used to meet a specific set of design criteria.

[0031] Further details, objectives, and advantages of the heat exchanger equipment, the processes for operating the heat exchanger equipment, and the methods of manufacture and use thereof will become apparent from the following description of some exemplary embodiments thereof. Attached Figure Description

[0032] Exemplary embodiments of heat exchanger equipment, processes for operating heat exchanger equipment, and methods of manufacturing and using the same are shown in the accompanying figures. It should be understood that similar reference numerals used in the figures can identify similar components.

[0033] Figure 1 (Figure 1) (It can also be called) Figure 1 (FIG. 1) is a block diagram of an exemplary embodiment of a plant 1 that can utilize an embodiment of the heat exchanger device 10. Figures 3 to 5 The first, second, or third exemplary embodiments of the heat exchanger device 10 shown can be used in this exemplary embodiment of the plant 1.

[0034] Figure 2 (Figure 2) (It can also be called) Figure 2 (FIG. 2) is a block diagram of an exemplary embodiment of a plant 1 that can utilize an embodiment of the heat exchanger device 10. Figures 3 to 5 The first, second, or third exemplary embodiments of the heat exchanger device 10 shown can be used in this exemplary embodiment of the plant 1.

[0035] Figure 3 (Figure 3) (It can also be called) Figure 3 (FIG. 3) is a schematic flowchart illustrating the process of operating a first exemplary embodiment of a heat exchanger device 10, wherein the heat exchanger device 10 can switch between an operable state OP and a temperature maintenance state TM.

[0036] Figure 4 (Figure 4) (It can also be called) Figure 4(FIG. 4) is a schematic flowchart illustrating the process of operating a second exemplary embodiment of the heat exchanger device 10, wherein the heat exchanger device 10 can switch between an operable state OP and a temperature maintenance state TM.

[0037] Figure 5 (Figure 5) (It can also be called) Figure 5 (FIG. 5) is a schematic flowchart illustrating the process of operating a third exemplary embodiment of the heat exchanger device 10, wherein the heat exchanger device 10 can switch between an operable state OP and a temperature maintenance state TM.

[0038] Figure 6 (Figure 6) (It can also be called) Figure 6 FIG. 6 is a flowchart illustrating an exemplary embodiment of the process of operating a heat exchanger device. Embodiments of plant 1 and heat exchanger device 10 can be configured to implement this exemplary embodiment of the process of operating the heat exchanger device.

[0039] The reference numerals used in the figures include the following: 1 Factory 3. Compression System (COMP.SYS) 5. Pre-purification Unit (PPU) 7 ASU heat exchanger units (HX) 9. Sources of Process Flow 21 10. Heat Exchanger Equipment (HX) 11. Liquefaction unit 12 Air Separation Unit (ASU) 13 Tower Components 14. Liquefaction Plant Feed 15. Liquefaction Equipment 15a Heating components of liquefaction equipment 15b Cold components of liquefaction equipment 15c Feed processing components of liquefaction equipment 20 Recirculation Temperature Difference Control Device 21 Factory Process Flow 22 Purification feed 22a First warm fluid flow 22b Second warm fluid flow 23 Refrigerant process fluid flow 23a First refrigerant fluid flow 23b Second refrigerant fluid flow 23c Third refrigerant fluid flow 25 valve 30 valve 31 Recirculation Piping Layout 40 valve 50 valve 100 First warm fluid feed pipe 110 First warm fluid heat exchanger output pipe 150 Second warm fluid feed pipe 160 Second warm fluid heat exchanger output pipe 200 First refrigerant fluid inlet pipe 201 First Separation Feed Pipeline Section 202 Cooling Recirculation Flow 203 First Separation Output Pipeline Section 204 Second Separation Feed Pipe Section 205 Second Separation Output Pipeline Section 210 First refrigerant output pipe 250 Warming recirculating fluid flow 260 Waste recirculated gas stream 300 Second refrigerant fluid inlet pipe 310 Second refrigerant output pipe 400 Third refrigerant fluid inlet pipe 410 Third refrigerant output pipe Argon gas TMM Temperature Maintenance Mechanism FGS Feed Gas System GN Gaseous Nitrogen GO (Gaseous Oxygen) LN liquid nitrogen LO Liquid Oxygen LP liquefaction equipment product flow OP operational status TDCD temperature difference control device TM Temperature Profile Maintenance Status S1 First Step S2 Second Step S3 Third Step Valves 25, 30, 40, and 50 are adjustable between the open and closed positions. Figure 4 and Figure 5 In the diagram, when the valve is displayed as a white line filled with black, it indicates that the valve is in the open position. When in the closed position, the valve is displayed as solid black. Detailed Implementation

[0040] refer to Figures 1 to 6Industrial plant 1 can be configured to receive one or more feed fluid streams or utilize one or more feed fluids and process them to form one or more product fluids. The product fluids can be used for storage and / or transportation. Alternatively, the product fluids can be used in another downstream plant or plant process (e.g., to form an oxidant stream for supply to a combustion unit for burning fuel, etc.).

[0041] In some embodiments, plant 1 may include a liquefaction unit 15, which may include a feed gas system (FGS). The feed gas system 15c may compress and / or process feed gas for supplying to at least one liquefaction unit to liquefy a product stream (e.g., a product liquid nitrogen stream, etc.). The feed gas system 15c may output a compressed gas stream, sufficiently purified to liquefy the feed gas stream, to a heat exchanger unit 10 for cooling therein, for supplying to a downstream liquefaction unit 15b configured to operate at a cold temperature (e.g., cryogenic or near-cryogenic temperature). The heat exchanger unit 10 may be in fluid communication with a differential temperature control device (TDCD) 20, which may selectively operate depending on the operability of the heat exchanger unit 10. Furthermore, the heat exchanger unit 10 may be in fluid communication with a cold component of the downstream liquefaction unit 15b for transferring feed gas, already cooled by the heat exchanger unit 10, to the liquefaction unit to liquefy the gas to form at least one product stream LP, which may be output for storage in a storage device or for another downstream application.

[0042] When heat exchanger device 10 is not operated to cool the feed to a preselected temperature range that may be suitable for downstream liquefaction components, heat exchanger device 10 can be adjusted from a first operable state to a second state (e.g., from a normally operable state to an inoperable state). In the second state, heat exchanger device 10 can receive a refrigerant flow as process flow 21 from one or more sources of at least one process flow 9, and no longer receives feed for precooling the feed. Such flow of the process flow can be actuated via adjusting a valve 25 positioned between the source of process flow 9 and heat exchanger device 10 to supply process flow 21 to the heat exchanger device when it is in an inoperable state, and to stop supplying process flow to the heat exchanger device when it is in an operable state, for achieving heat transfer of the feed flow (e.g., precooling feed for liquefaction, etc.) during operation of plant 1.

[0043] At least one source of process flow 9 may be the heat exchanger 7 of an air separation unit (ASU), a cold fluid flow provided by the tower of ASU 12, evaporating gas output from a storage tank storing cryogenic liquid, or other suitable refrigerant. The refrigerant feed output from at least one source of process flow 9 may be supplied to heat exchanger device 10 to downstream liquefaction unit 15b when heat exchanger device 10 is not receiving a fluid flow for cooling the feed, in order to maintain the temperature profile of heat exchanger device 10 (e.g., maintain a preselected temperature difference between the warm and cold ends of heat exchanger device 10). The temperature profile to be maintained may be selected such that heat exchanger device 10 remains at its operating temperature profile when not in operation. This can reduce the thermal stress that may arise from the heat exchanger device when it is not in operation to cool the feed supplied to liquefaction unit 15b, and can also allow for faster restart of heat exchanger device 10 when it returns to an operating state for cooling the feed output from FGS 15c.

[0044] Process stream 21 can be supplied as refrigerant to heat exchanger device 10 at a first cooler temperature and output from heat exchanger device 10 for discharge or recirculation back to the source of at least one process stream 9. Alternatively, output warming refrigerant used to maintain the temperature profile of heat exchanger device 10 can be output from heat exchanger device 10 and supplied to temperature difference control device 20, wherein the stream can be heated or cooled to a recirculation temperature for supply back to heat exchanger device 10 to exchange heat with the cooler refrigerant stream supplied to heat exchanger device 10. The cooled recirculated refrigerant stream can then be output from heat exchanger device 10 for discharge, recirculation back to refrigerant source 12, or otherwise used in downstream processes or other plant processes. Temperature difference control device 20 can be operated to help maintain the temperature difference between the refrigerants supplied to the heat exchanger device, thereby helping to maintain the temperature profile of the heat exchanger and preventing heat exchanger device 10 from becoming overcooled when it is in a second operational state.

[0045] When resuming liquefaction operation, heat exchanger unit 10 can return to its first operable state, whereby refrigerant is no longer supplied to heat exchanger unit 10, and feed from FGS 15c is supplied to heat exchanger unit 10. Due to the temperature maintenance profile of heat exchanger unit 10, this adjustment and liquefaction recovery during operation can occur more quickly, allowing for a faster return to liquefaction operation.

[0046] Operational adjustments between active liquefaction and non-liquefaction operations can occur based on the availability of renewable electricity and / or other operational criteria. Heat exchanger unit 10 and TDCD 20 can be operated to facilitate adjustments in an operational state, enabling liquefaction operations to be brought online more quickly, to utilize renewable electricity (e.g., renewable electricity provided by solar or wind power) more efficiently, and / or to use available electricity at a lower cost.

[0047] For example, in some embodiments, plant 1 may include a compression system 3 (COMP. SYS.) that receives a gas feed and compresses it to a preselected feed pressure for use as feed downstream of compression system 3 for downstream processing in plant 1. In some embodiments, one or more booster compressors may be located downstream of the compression system to also increase the pressure of one or more portions of the feed fluid output from compression system 3.

[0048] Compression system 3 can output pressurized feed to pre-purification unit (PPU). In some embodiments, PPU 5 can be configured as an adsorption system. For example, PPU 5 may include a thermospin-assay (TSA) system, a pressure-spin-assay (PSA) system, or other types of adsorption systems. PPU 5 can be configured to remove one or more impurities from the pressurized feed fluid output from compression system 3, for supplying the purified feed to the main heat exchanger unit 7 of ASU 12. For example, PPU 5 can utilize one or more adsorbents having adsorbent material therein to remove water, carbon dioxide, and / or other components of the feed to purify the fluid feed, so that the purified feed can be supplied to the main heat exchanger unit 7.

[0049] The heat exchanger unit (HX) 7 of ASU 12 may include at least one heat exchanger configured to cool the pressurized and purified feed output from PPU 5 via heat exchange with one or more refrigerant process fluid flows supplied to the heat exchanger unit 7 when Plant 1 is operating to produce one or more product fluids. The one or more refrigerant process fluid flows may be warmed by absorbing heat from the purified feed supplied to the heat exchanger unit 7 to output a warmed refrigerant process fluid flow for discharge, as regeneration gas for the PPU, or for other uses of the warmed fluid output from the heat exchanger unit 7.

[0050] In some embodiments, the purified feed supplied to the heat exchanger device 7 for cooling may include one or more fluid streams in a temperature range between 0°C and 50°C. One or more refrigerant process fluid streams supplied to the heat exchanger device 7 for cooling the purified feed may be in a low-temperature range (e.g., between -150°C and -200°C, or between -160°C and -195°C, etc.). The central portion of the heat exchanger device 7, located inside the heat exchanger housing between its inlet and outlet ends where it receives the feed and refrigerant streams and outputs cooled feed and warmed refrigerant streams, may have a temperature profile during operation, wherein heat from the warmer purified feed stream is transferred to the cooler refrigerant process fluid stream 23, which may be significantly colder than ambient conditions. In portions adjacent to the ends of the heat exchanger device 7, the temperature may be lower, at which the cooled purified feed is output from the heat exchanger device 7, and in portions adjacent to the ends of the heat exchanger device 7, the temperature may be warmer, at which warm purified feed is supplied to the heat exchanger device.

[0051] The cooled, purified feed from the fluid output from heat exchanger unit 7 can be supplied to a downstream processing unit of plant 1. In some embodiments, the downstream processing unit may be, for example, a tower assembly 13 of an air separation unit (ASU) 12. In such embodiments, the purified feed may be purified air, and the feed may be air. ASU 12 may include multiple towers of tower assembly 13, including low-pressure and high-pressure towers, for receiving the purified air feed cooled by heat exchanger unit 7, for separating the air to form one or more product fluids. The one or more product fluids may include, for example, gaseous nitrogen (GN), liquid nitrogen (LN), gaseous oxygen (GO), and liquid oxygen (LO). In some embodiments, tower assembly 13 may also include one or more additional towers that may be positioned and configured to receive fluid from the low-pressure and / or high-pressure towers to also form an argon (Ar) product stream and / or other product streams. The argon product stream that can be formed may be liquid argon or gaseous argon, for example, to be supplied to a storage tank or to a downstream process where argon fluid is available.

[0052] Tower assembly 13 may also output one or more nitrogen streams. At least one of the nitrogen streams may be sufficiently pure to form a liquefied product stream. Such a stream may be output from tower assembly 13 to be supplied to heat exchanger device 7 for use as a refrigerant to cool the purified feed air supplied to tower assembly 13. The nitrogen product stream may then be supplied as liquefier feed 14 to warm liquefaction unit 15a (Liq. Comp. (warm)). For example, the warm liquefaction unit may include a feed compressor or other elements of the feed gas system 15c of liquefaction device 15. The feed gas system FGS of warm liquefaction unit 15a may also include purification elements (e.g., an adsorber configured to remove impurities from the stream). The feed gas output from feed gas system FGC may be supplied to heat exchanger device 10 to undergo heat transfer therein.

[0053] For example, heat exchanger device 10 may be a pre-liquefied feed cooler or a cooler for liquefaction device 15, used to cool the purified feed stream before supplying it to a colder liquefaction unit 15b for liquefaction (Liq. Comp. (cold)) to produce a product stream LP for storing liquefied products or for other uses of the liquefied product stream LP. Heat exchanger device 10 may also receive a fluid stream that can be used as a refrigerant for cooling the fluid feed. The fluid stream that can be used as a refrigerant for cooling the fluid feed may be a feed recirculation section, which may be supplied to one or more expanders or other elements to facilitate cooling of the feed for liquefaction. During operation of heat exchanger device 10 of liquefaction unit 11 for liquefaction operations, the fluid stream that can be used as a refrigerant for cooling the fluid feed may also include one or more streams output from the cold liquefaction unit, for example, before a discharge or recirculation stream. The cooled feed can be cooled to a preselected liquefaction feed temperature via one or more downstream cold liquefaction components 15b (e.g., one or more liquefaction units or liquefaction elements) to undergo liquefaction and / or depressurization.

[0054] In some embodiments, the feed supplied to the heat exchanger device 10 for cooling may include one or more fluid flows in a temperature range between 0°C and 50°C. One or more refrigerant process fluid flows 23 supplied to the heat exchanger device 10 for cooling the purified feed may be in a low-temperature range (e.g., between -150°C and -200°C, or between -160°C and -195°C, etc.). The central portion of the heat exchanger device 10, located inside the heat exchanger housing between its inlet and outlet ends where it receives the feed and refrigerant flows and outputs cooled feed and warmed refrigerant flows, may have a temperature profile during operation, wherein heat from the warmer purified feed flow is transferred to the cooler refrigerant process fluid flow 23, which may be significantly colder than ambient conditions. In the portion adjacent to the end of the heat exchanger device 10, the temperature may be lower, at which point cooled purified feed is output from the heat exchanger device 10 for supply to one or more downstream liquefiers of the liquefaction device 15, and in the portion adjacent to the end of the heat exchanger device 10, the temperature may be warmer, at which point warm purified feed is supplied to the heat exchanger device.

[0055] In some embodiments, the compression system and other components of plant 1 (e.g., compression system 3, feed compressor of feed gas system 15c of liquefaction unit 15, and / or other components of liquefaction unit 15, etc.) can be operated using renewable energy sources (e.g., electricity powered by solar panels, wind turbines, and / or other types of renewable energy). Other embodiments may rely on conventional power generation systems (e.g., natural gas or coal-fired power generation systems, etc.). Embodiments of plant 1 can be configured such that liquefaction unit 11 of plant 1 is operable when sufficient renewable electricity is available to power operation or when the price of electricity is at or below a preselected threshold. When renewable electricity available to power operation is insufficient or when the price of electricity is at or above the preselected threshold, operation of liquefaction unit 11 of plant 1 can be shut down, and therefore liquefaction unit 11 of plant 1 is not operated (e.g., liquefaction unit 15 is not operated to form one or more product streams, and heat exchanger unit 10 is not used to cool fluids to support the operation of liquefaction unit 10 to liquefy fluids, etc.).

[0056] An embodiment of Plant 1 can be configured such that the liquefier 11 and its heat exchanger device 10 of Plant 1 can switch between an operational and inoperable (or off) state once or more per day or several times per week (e.g., between 10 and 31 times per month, or between 15 and 25 times per month, etc.). However, due to the temperature cycling that may occur between when the heat exchanger device 10 is operated to provide heat exchange between warm and cold streams during operation of the liquefier 11 and when the heat exchanger device 10 is not so utilized during periods when the liquefier 11 of Plant 1 is not operated or is off, such an operational configuration may impose significant thermal stress on the heat exchanger device 10. For example, the intermediate temperature of the heat exchanger device 10 may cycle between -50°C or -100°C (when the liquefier 11 of Plant 1 is operational) and ambient temperature (when the liquefier 11 of Plant 1 may be in an inoperable state). If the heat exchanger device 10 is attributed to differential thermal expansion and contraction cycling between these temperatures due to temperature gradients, this type of cyclic thermal change can result in significant thermal stress on the components of the heat exchanger device. And where such cycles can occur regularly, such stress can be a significant factor that can greatly reduce the lifespan of the heat exchanger device 10 (e.g., leaks and / or failures in the heat exchanger device 10 may occur unexpectedly due to the frequency of such thermal stress events).

[0057] To help avoid such problems and enable the liquefier 11 of plant 1 to more effectively and reliably regulate between operational and inoperable states to better utilize renewable energy availability and / or electricity pricing changes, the heat exchanger device 10 can be configured to utilize a temperature maintenance mechanism (TMM) to help prevent significant thermal cycling due to the liquefier 11 of plant 1 switching from its operational state to an inoperable state (or a shut-off state). The TMM can be configured to facilitate the use of at least one fluid through the heat exchanger device 10 when the liquefier 11 of plant 1 is in an inoperable state to maintain the heat exchanger device 10 at or near the operational temperature profile of the heat exchanger device 10 when the liquefier 11 of plant 1 is operational. For example, embodiments of the TMM can be configured and operated such that the warm end of the heat exchanger device 10 is above -20°C or another suitable temperature, and the cold end of the heat exchanger device 10 is below -100°C or another suitable temperature, to help minimize or avoid thermal stress caused by the heat exchanger device 10 when the liquefier 11 of the plant 1 is not operating (e.g., due to insufficient available renewable electricity and / or due to electricity prices exceeding a preselected threshold, etc.). In some embodiments, the TMM can be configured such that the middle of the heat exchanger device (or the central portion of the heat exchanger device) has a temperature profile with a relatively gentle slope, wherein the temperature may be in the range, for example, between -20°C and -100°C or in another suitable temperature range.

[0058] If possible Figures 3 to 5 It is best seen that the TMM can be configured such that the heat exchanger device 10 is not used when the liquefier 11 of plant 1 is in an operational state (OP). However, when the liquefier 11 of plant 1 is regulated to a non-operating state or a shut-off state, the TMM can be activated and the heat exchanger device 10 can be regulated to a temperature profile maintenance state (TM). When the liquefier 11 of plant 1 returns to an operational state (OP) (e.g., due to changes in electricity pricing or renewable energy availability), the heat exchanger device 10 can also be regulated back to its operational state (OP), and the TMM can be deactivated in conjunction with the switch from the temperature profile maintenance state (TM) to the operational state (OP). The liquefier 11 of plant 1 and the heat exchanger device 10 of the liquefier 11 can be regulated between these different states multiple times a month (e.g., once a day, multiple times a day, several times a week, multiple times a week, etc.).

[0059] For example, heat exchanger device 10 may be configured to receive purified feed 22 as a first warm fluid stream 22a and a second warm fluid stream 22b. These first warm fluid streams 22a and second warm fluid streams 22b may also be considered as a first purified feed stream and a second purified feed stream. For example, these streams may be portions of purified feed from the feed gas system FGS, used for pre-cooling before being sent to a downstream liquefaction unit or other downstream liquefaction equipment that may be located downstream of heat exchanger device 10. In such embodiments, one such portion of the purified feed may be at a higher pressure than the other such streams.

[0060] The first warm fluid flow 22a can be supplied to the heat exchanger device 10 via the first warm fluid feed pipe 100 connected between the feed gas system FGS and the heat exchanger device 10. The second warm fluid flow 22b can be supplied to the heat exchanger device 10 via the second warm fluid feed pipe 150 connected between the feed gas system FGS and the heat exchanger device 10.

[0061] The heat exchanger device 10 may also be positioned to receive one or more refrigerant fluid flows 23. For example, the heat exchanger device 10 may be positioned to receive a first refrigerant fluid flow 23a, a second refrigerant fluid flow 23b, and a third refrigerant fluid flow 23c. Each refrigerant fluid may be at a cryogenic temperature. In some embodiments, the refrigerant fluid may include nitrogen and / or oxygen, and may be, for example, a recirculated or waste stream output from the tower of at least one downstream liquefier and / or ASU 12.

[0062] For example, heat exchanger device 10 may be connected to a first refrigerant fluid feed line 200, a second refrigerant fluid feed line 300, and a third refrigerant fluid feed line 400. A first refrigerant fluid flow 23a may be supplied to heat exchanger device 10 via the first refrigerant feed line 200, a second refrigerant fluid flow 23b may be supplied to heat exchanger device 10 via the second refrigerant feed line 300, and a third refrigerant fluid flow 23c may be supplied to heat exchanger device 10 via the third refrigerant feed line 400. In some embodiments, the first refrigerant feed line 200, the second refrigerant feed line 300, and the third refrigerant feed line 400 may be connected between heat exchanger device 10 and at least one tower of downstream liquefaction equipment and / or ASU 12 (e.g., such lines may be connected between the low-pressure or high-pressure tower of ASU tower assembly 13 and heat exchanger device 10 or may be connected between heat exchanger device 10 and downstream refrigeration equipment).

[0063] The heat exchanger device 10 may include one or more individual heat exchangers and may have different outlet pipes for discharging a cooled purified feed stream and a warmed refrigerant stream supplied to the heat exchanger device 10. For example, one or more heat exchangers of the heat exchanger device 10 may include a first heat exchanger. In some embodiments, the heat exchanger device 10 may also include additional heat exchangers (e.g., a second heat exchanger, a third heat exchanger, etc.).

[0064] The heat exchanger device 10 may include a first warm fluid heat exchanger outlet pipe 110 through which the cooled, warmer fluid of the first warm fluid flow 22a can be output from the heat exchanger device 10. The pipe may be located at an intermediate position along an individual heat exchanger of the heat exchanger device 10, or it may be output from the cold end of the heat exchanger device 10.

[0065] The heat exchanger device 10 may also include a second warm fluid heat exchanger outlet pipe 160 through which the cooled warmer fluid of the second warm fluid flow 22b can be output from the heat exchanger device 10.

[0066] The heat exchanger device 10 may also include an outlet pipe for discharging a warming refrigerant flow that can be supplied to the heat exchanger device. For example, the heat exchanger device 10 may include a first refrigerant outlet pipe 210, a second refrigerant outlet pipe 310, and a third refrigerant outlet pipe 410. A warming first refrigerant fluid flow 23a may be discharged from the heat exchanger device 10 via the first refrigerant outlet pipe 210, a warming second refrigerant fluid flow 23b may be discharged from the heat exchanger device 10 via the second refrigerant outlet pipe 310, and a warming third refrigerant fluid flow 23c may be discharged from the heat exchanger device 10 via the third refrigerant outlet pipe 410.

[0067] When heat exchanger device 10 is regulated to its temperature maintenance state TM, the warm feed stream and refrigerant feed stream may no longer be supplied to heat exchanger device 10 due to the shutdown of liquefier 11 in plant 1. However, at least one of the feed line or refrigerant line connected to heat exchanger device 10 can be used to receive refrigerant fluid that can pass through the heat exchanger to provide cooling therein, helping to maintain the temperature profile of heat exchanger device 10 when liquefier 11 in plant 1 is inoperable and heat exchanger device 10 is in temperature maintenance state TM. This refrigerant fluid can be provided via refrigerant process stream 21, which is operatively connected to heat exchanger device 10 to direct cooling fluid to heat exchanger device 10 when liquefier 11 in plant 1 is regulated to a shut-off or inoperable state. Refrigerant process stream 21 can be the vaporized vapor of a cryogenic liquid fluid (e.g., liquid oxygen, liquid nitrogen, liquid argon, or liquid hydrogen vaporized gas) that can be stored in at least one storage tank. For example, such a gas may be at a low temperature and discharged from the storage tank for venting to reduce the pressure in the storage tank or to maintain the pressure in the storage tank at or below a preselected storage pressure. In some embodiments, the refrigerant fluid may be supplied to the heat exchanger device 10 via a first refrigerant fluid inlet line 200, a second refrigerant fluid inlet line 300, or a third refrigerant fluid inlet line 400, wherein such inlet lines may be operatively connected to the storage tank via adjusting one or more valves in a piping arrangement positioned between the heat exchanger device 10 and the storage tank.

[0068] Alternatively, when the liquefier 11 of plant 1 is inoperable and the heat exchanger device 10 is in temperature maintenance state TM, the refrigerant gas supplied to the heat exchanger device 10 can be supplied as a refrigerant process stream 21 via another cold process gas, which can be supplied by another process element of the plant or an adjacent plant, or it can be a separator evaporator gas, which can be supplied via the separator of ASU 12 or other plant elements or plant units when the liquefier 11 of the plant is inoperable. The refrigerant process stream 21 utilized can also be supplied via a combination of such sources (e.g., in some embodiments, such a combination of sources can be a source of at least one process stream 9, etc.).

[0069] When heat exchanger device 10 is in temperature maintenance state TM, a refrigerant flow can be provided through the heat exchanger device to maintain the temperature profile of the heat exchanger device 10 at the same or a pre-selected similar temperature as when the plant's liquefier 11 is operable to produce the product fluid. For example, a refrigerant process flow 21 can be provided so that the warm end of the heat exchanger device 10 is closer to ambient temperature, the cold end of the heat exchanger is at or near a low temperature, and one or more individual heat exchangers of the heat exchanger device 10 can maintain the temperature profile of the warm and cold ends of the heat exchanger device 10 relative to the ambient temperature and the low temperature.

[0070] exist Figure 4 In an exemplary embodiment, the warmed refrigerant gas after passing through the heat exchanger device 10 can be discharged or sent to another plant component after the warmed refrigerant gas is output from the heat exchanger device 10 to help maintain the temperature profile of the heat exchanger device 10. In other embodiments, the refrigerant process gas can be recycled for further use as a working fluid to help maintain the temperature profile of the heat exchanger device 10 when operating in a temperature maintenance state TM. Figure 4 and Figure 5 Different recycling schemes that can be used in different embodiments are shown.

[0071] For example, the TMM may include a recirculation piping arrangement 31, which includes a recirculation line connecting the heat exchanger outlet line and the heat exchanger feed line. The recirculation piping arrangement 31 may also include a recirculation temperature differential control device 20, which is positioned to regulate the temperature of fluid output from the heat exchanger unit 10 before it is recirculated back to the heat exchanger unit 10, to be used as a heating fluid therein as part of the recirculation of the refrigerant process fluid, for maintaining the temperature profile in the heat exchanger unit when the heat exchanger unit 10 operates in temperature sustaining state TM. The recirculation piping arrangement 31 may also include at least one recirculation valve 30, which is adjustable between a closed position and an open position. In the closed position, fluid recirculation may not occur. In the open position of valve 30, fluid can be recirculated via the recirculation piping arrangement 31, such that the recirculated fluid is heated by the recirculation temperature differential control device 20, which is configured as a heating device, and then supplied back to the heat exchanger unit 10.

[0072] For example, in Figure 4 In an exemplary embodiment, when the heat exchanger device 10 is adjusted to operate in a temperature maintenance state TM, fluid can be supplied solely through a single inlet and a single outlet conduit of the heat exchanger device for conveying the refrigerant process flow 21 through the heat exchanger device 10, thereby helping to maintain the temperature profile of the heat exchanger device 10 as mentioned above. Figure 4 In the example shown, when the liquefier 11 of plant 1 is off or inoperable and the heat exchanger unit 10 is in temperature sustaining state TM, the first refrigerant fluid feed line 200 may receive the refrigerant process flow 21. In some embodiments, this may be the only fluid flow supplied to the heat exchanger unit 10 when it is operating in temperature sustaining state TM. As mentioned above, the refrigerant process flow 21 may be received from at least one storage tank as vaporized liquid fluid (e.g., liquid oxygen, liquid nitrogen, liquid argon, or liquid hydrogen vaporized gas) stored in the storage tank. Alternatively, the refrigerant gas supplied to the heat exchanger unit 10 when the liquefier 11 of plant 1 is inoperable and the heat exchanger unit 10 is in temperature sustaining state TM may be supplied as the refrigerant process flow 21 via another cold process gas, which may be supplied by another process element of plant 1 or an adjacent plant, or may be a separator vaporized gas, which may be supplied via a separator of the ASU or other plant element or plant unit 1 when the liquefier 11 of plant 1 is inoperable. The refrigerant process flow 21 used can also be provided via a combination of such sources.

[0073] The heat exchanger device 10 can receive the refrigerant process flow 21 via a first refrigerant fluid feed line 200, and the fluid can pass through the heat exchanger device 10 to maintain the temperature profile of the heat exchanger device 10, and be discharged from the heat exchanger device via a first refrigerant fluid output line 210. A recirculation valve 30, arranged in a recirculation pipeline, can be adjusted from a closed position to an open position, such that the refrigerant process flow 21 discharged from the heat exchanger device can be recirculated back to the heat exchanger device 10 after being discharged from the heat exchanger device 10 via the first refrigerant fluid output line 210. For example, the recirculation valve 30 can be connected to a recirculation pipeline extending between the first refrigerant fluid output line 210 and the third refrigerant output line 410, or to other pipelines of the heat exchanger device 10 for transferring the refrigerant process flow 21 discharged from the heat exchanger device 10 back to the heat exchanger device 10. The recirculation temperature differential control device 20 can be positioned in fluid connection with the recirculation piping arrangement 31, such that the recirculation fluid can be heated to a preselected temperature, resulting in a recirculation back to the heat exchanger unit 10 to simulate a warmed recirculation fluid flow 250 supplied to the heat exchanger unit 10 as a relatively warm feed to the environment when the liquefier 11 of plant 1 is operational. When the heat exchanger unit operates in temperature maintenance state TM, the warmed recirculation fluid can exchange heat with the cooler refrigerant process flow 21 supplied to the heat exchanger via the first refrigerant fluid feed line 200, such that the temperature profile in the heat exchanger unit 10 can be maintained within the preselected temperature range. The warmed recirculation process gas can then be output from the heat exchanger unit 10 as a waste recirculation gas flow 260, which can be discharged or recycled for further use in another plant process. In this configuration, the recirculation of the process flow can result in only a single recirculation pass before the discharge or other treatment of the waste recirculation gas flow 260.

[0074] When the liquefier 11 of plant 1 returns to the operable state, the temperature difference control device 20 can be deactivated and the recirculation valve 30 can be adjusted to the closed position to return the heat exchanger equipment to its operable state OP.

[0075] The recirculation temperature difference control device 20 can be configured as a heating device, such as an electric heater, an ambient air heat exchanger, a heat exchanger utilizing cooling water or ambient temperature water, or other types of heating devices or heaters for heating the recirculated gas initially output from the refrigerant process stream 21 from the heat exchanger device 10 to a preselected temperature, which can simulate the feed temperature of the purified feed 22 supplied to the heat exchanger device 10 when the liquefier 11 of plant 1 is operational. Surprisingly, the increased cost and power consumption of the recirculation temperature difference control device 20 can be offset by avoiding or minimizing the thermal stress that the heat exchanger device 10 may experience and by the improved speed at which the liquefier 11 of plant 1 can reach full productivity when it returns to an operational state. For example, the heat exchanger device 10 can be used more quickly for effective pre-cooling of the feed, thanks to the fact that the heat exchanger device maintains its temperature profile when the liquefier 11 of plant 1 is inoperable or shut down. For example, this could allow the liquefier 11 of plant 1 to come into its operational state more quickly in order to make more efficient use of available renewable electricity and / or lower electricity pricing.

[0076] Figure 5 Another type of recirculation method is shown, similarly using recirculation piping arrangement 31. However, Figure 5 The embodiments utilize a split-flow arrangement, wherein when the heat exchanger device 10 is in its operational state OP, the feed flow of fluid supplied to the heat exchanger device 10 can be split into first and second portions for supply to the heat exchanger device 10, and this split arrangement can also be used for the refrigerant process flow 21 recirculation when the heat exchanger device 10 is operating in its temperature maintenance state TM. For example, the first refrigerant fluid feed conduit 200 may include a first split feed conduit section 201 and a second split feed conduit section 204 for splitting the first refrigerant fluid supplied to the heat exchanger device 10 via the conduit into multiple portions for passage through the heat exchanger device 10.

[0077] The first refrigerant fluid output conduit 210 may include a first separate output conduit section 203 through which a first portion of the first refrigerant fluid, delivered to the heat exchanger device 10 via the first separate feed conduit section 201, is output from the heat exchanger device 10. The first refrigerant fluid output conduit 210 may also include a second separate output conduit section 205 through which a second portion of the first refrigerant fluid, delivered to the heat exchanger device 10 via the second separate feed conduit section 204, is output from the heat exchanger device 10. When the heat exchanger device 10 is in its operational state, and when the valve is in its open position, these portions may be combined and pass through the recirculation valve 30. These separate sections of the feed and output conduits may also be used as a recirculation conduit arrangement 31 via recirculation valves 30, 40, and 50, which are fluidly connected to the first refrigerant fluid output conduit 210 and the first refrigerant fluid feed conduit 200.

[0078] For example, when Figure 5 When the heat exchanger device 10 of the illustrated embodiment is adjusted to its temperature maintenance state TM, the first recirculation valve 30 can be adjusted to the closed position, the valve 50 of the first separation feed pipe section 201 can also be adjusted from the open position to the closed position, and the valve 40, which is also in fluid communication with the first separation feed pipe section 201, can be adjusted from the closed position to the open position. Then, the refrigerant process flow 21 can be supplied to the heat exchanger device 10 via the first refrigerant feed pipe 200, so that the fluid passes through the second separation feed pipe 204, through the heat exchanger device 10, and exits the heat exchanger device via the second separation output pipe section 205. The refrigerant fluid can then be heated via a recirculation temperature differential control device 20, which is configured as a heating device and is in fluid communication with the second separate output pipe section 205 and the first separate output pipe section 203. This allows the warmed refrigerant from the refrigerant process flow 21 output from the heat exchanger unit 10 to be further heated via the recirculation temperature differential control device 20 and then recirculated back to the heat exchanger unit 10 via the first separate output pipe 203, simulating the feed that can be supplied to the heat exchanger unit 10 when the liquefier 11 of the plant 1 is operational. This warmed recirculated refrigerant fluid flow 250 can exchange heat with another portion of the refrigerant process flow 21 passing through the heat exchanger unit to be output as a cooled recirculated flow 202 through the first separate feed pipe section 201. This cooled recirculated flow can be directed away from the heat exchanger unit 10 via an open valve 40 for discharge or for other uses (e.g., recovery to return to a storage tank from which the fluid may have originated).

[0079] After the liquefier 11 in plant 1 returns to an operable state by closing valve 40 and opening valves 30 and 50, the heat exchanger unit 10 can return to its operable state. Since the temperature difference control device 20 may not be needed when the heat exchanger unit 10 is in its operable state, it can also be deactivated. In some embodiments, a bypass piping arrangement (not shown) may be present such that fluid exiting from the second separate output pipe 203 when the heat exchanger unit 10 is in its operable state OP can bypass the recirculation temperature difference control device 20 as it travels toward the first refrigerant output pipe 210. Such a bypass configuration allows fluid to bypass the non-operating temperature difference control device 20 when the heat exchanger unit 10 is in its operable state OP.

[0080] Embodiments of the heat exchanger device 10 can also be used in further embodiments, wherein the temperature difference control device 20 can be configured as a cooling device rather than a heating device. In some of these types of embodiments, the refrigerant process flow 21 may become significantly warmer as it passes through the heat exchanger device 10 and may need to be cooled for recirculation to provide the desired temperature profile of the heat exchanger device 10 via the recirculation of the flow. In such configurations, the temperature difference control device 20 can be configured as a cooling device by being configured as an expander, cooler, Joule-Thomson (JT) valve, or other suitable type of cooling device.

[0081] In other embodiments where the temperature difference control device 20 can be used as a cooling device, the process flow 21 delivered to the heat exchanger device 10 can be an ambient temperature fluid and can be cooled via the temperature difference control device 20, which is configured as a cooling device so that when the process flow 21 is recirculated back to the heat exchanger device 10, it can be used as a refrigerant to maintain the temperature profile of the heat exchanger device 10. In such a configuration, the initially supplied process flow 21 can be supplied to the warm end of the heat exchanger (e.g., via a heat exchanger feed line through which purified feed is supplied to the heat exchanger device, such as a first warm fluid feed line 100), and can be recirculated back to the heat exchanger via a recirculation line arrangement positioned such that the process flow can be cooled and recirculated back to the heat exchanger device 10 to be used as a refrigerant to maintain the temperature profile in the heat exchanger device 10. In such a configuration, the temperature difference control device 20 can be configured as a cooling device by being configured as an expander, cooler, or Joule-Thomson (JT) valve.

[0082] The embodiment can be configured such that the temperature difference control device 20 can control the temperature of the warming refrigerant fluid to be recirculated back into the heat exchanger device 10 to help maintain the temperature profile of the heat exchanger to simulate its temperature profile when it is in its operational state. The provided temperature control can be performed to manage the temperature gradient between the warm and cold ends of the heat exchanger device 10 to simulate the gradient that exists when the heat exchanger device 10 is operational for feed heat transfer, to provide feed for liquefaction or other purposes at a desired preselected temperature, so that thermal stress that could act on the heat exchanger device 10 due to the inoperability of downstream equipment (e.g., liquefiers, etc.) can be avoided or significantly reduced.

[0083] An embodiment of Plant 1, its liquefier 11, and heat exchanger device 10 can be configured to implement a method of operating the heat exchanger device 10. In a first step, the heat exchanger device 10 can be operated when the liquefier 11 of Plant 1 is operable. In a second step S2, the liquefier 11 of Plant 1 can be shut down (e.g., due to unavailability of renewable electricity, due to excessively high electricity pricing, etc.), and the supply of warm fluid and refrigerant fluid can be stopped (e.g., the supply of purified nitrogen gas stream output from the tower assembly 13 of the ASU and the supply of refrigerant fluid via downstream liquefier elements can be stopped). Then, a fluid (e.g., process flow 21) can be supplied to the heat exchanger device 10 to maintain the temperature profile of the heat exchanger device 10. Examples of such a supply of process flow 21 have been discussed above. In some embodiments, process flow 21 may be recirculated after it is initially output from heat exchanger device 10, such that the recirculated process flow may be a recirculated process gas for undergoing heat exchange with process flow 21 initially supplied to heat exchanger device 10, to simulate the heat exchange that occurs via warm fluid and refrigerant fluid supplied to heat exchanger device 10 when liquefier 11 of plant 1 is operational.

[0084] As mentioned above, in some embodiments, the temperature of the recirculation process flow can be regulated by using the temperature difference control device 20. In some embodiments, the recirculation process flow can be a one-time recirculation pass, such that after being recirculated back through the heat exchanger device 10, the utilized fluid is discharged or transported elsewhere for other uses in the plant 1.

[0085] In the third step S3, the liquefaction operation can be resumed or restarted (e.g., the operation of liquefier 11 can be resumed or restarted). In response to the resumption of plant operation, the maintenance of the temperature profile of the heat exchanger device 10 can be stopped, and the supply of warm fluid and refrigerant fluid can be resumed, allowing the warm fluid to undergo cooling and the refrigerant fluid to undergo heating via heat exchange with the warm fluid. The process can then return to the first step S1, allowing the heat exchanger device 10 to operate when the liquefier 11 of plant 1 is operable. In such operation, the warm fluid cooled by the heat exchanger device 10 can be cooled to a cryogenic temperature suitable for supply to, for example, a liquefier or other types of equipment that can operate at cryogenic temperatures.

[0086] In other embodiments of this process, the heat exchanger device 10 may be operational when another type of plant process utilizing the heat exchanger device 10 is operational in the first step S1. In the second step S2, in response to the cessation of the other type of plant process utilizing the heat exchanger device 10 (e.g., due to a lack of available renewable electricity, electricity pricing, etc.), the supply of fluid to the heat exchanger device 10 to undergo cooling or heating may be stopped. In response to a change in the operational state of the plant process, the supply of fluid to the heat exchanger device 10 may also be initiated in the second step S2 to maintain the temperature profile of the heat exchanger device 10. In some embodiments (and as discussed above), the temperature difference control device 20 may be used to regulate the temperature of the fluid to allow the fluid to be recirculated back to the heat exchanger device 10, and to facilitate the maintenance of the temperature profile of the heat exchanger device 10.

[0087] In the third step S3, the maintenance of the temperature profile of the heat exchanger device 10 can be stopped, and the supply of fluid to the heat exchanger device 10 to undergo cooling and / or heating can be resumed in response to the resumption of other plant processes utilizing the heat exchanger device 10 (e.g., due to the availability of renewable electricity or a change in electricity pricing to a pre-selected appropriate level, etc.), as part of the cooling and / or heating process of downstream processes utilizing the heat exchanger device 10 (e.g., air separation, nitrogen liquefaction, etc.). The process can then return to the first step S1, allowing the heat exchanger device 10 to be operated to support the plant processes utilizing it.

[0088] The embodiments of the liquefier 11 of plant 1, plant 1, and heat exchanger equipment 10 can be used in the embodiments of this process. Such embodiments can also be used to implement embodiments of this process.

[0089] The process may also include additional steps or features. For example, the process flow used to maintain the temperature profile of the heat exchanger can be recirculated via a recirculation piping arrangement as discussed above. Such recirculation can utilize the temperature difference control device 20 discussed above.

[0090] In some embodiments, the process flow 21 used to maintain the temperature of the heat exchanger device may be the vaporized vapor of a cryogenic liquid fluid (e.g., liquid oxygen, liquid nitrogen, liquid argon, or liquid hydrogen vaporized gas) that can be stored in at least one storage tank. For example, such a gas may be cryogenic and discharged from the storage tank for venting to reduce the pressure in the storage tank or to maintain the temperature in the storage tank at or below a preselected storage pressure. In some embodiments, the refrigerant fluid may be supplied as process flow 21 to the heat exchanger device 10 via a first refrigerant fluid inlet line 200, a second refrigerant fluid inlet line 300, or a third refrigerant fluid inlet line 400, wherein such lines may be operatively connected to the storage tank via adjusting one or more valves in a piping arrangement positioned between the heat exchanger device 10 and the storage tank. Alternatively, process flow 21 can be supplied to heat exchanger 10 via another cold process gas as refrigerant process flow 21 when liquefier 11 at plant 1 is inoperable and heat exchanger equipment 10 is in temperature maintenance state TM. This other cold process gas can be supplied by another process element at the plant or an adjacent plant, or it can be separator evaporation gas, which can be supplied via separators at the ASU or other plant elements or plant units when the plant is inoperable. The refrigerant process flow 21 used can also be supplied via a combination of such sources.

[0091] In some other embodiments, the process flow utilized in the second step S2 of the process may be an ambient temperature flow, and the temperature difference control device 20 may be configured to cool the flow for recirculation of the fluid as discussed above.

[0092] In some embodiments, the heat exchanger device 10 may be positioned as a heating feed stream rather than a cooling feed stream. Downstream equipment of the heat exchanger device 10 may utilize the heated stream for other processes (e.g., fuel combustion). In such embodiments, the process stream 21 may originate from a heating medium source rather than a refrigerant source.

[0093] It should also be understood that other modifications can be made to meet a specific set of criteria for different embodiments of Plant 1, the liquefier 11 of Plant 1, the heat exchanger equipment 10, or the process. For example, the arrangement of valves, pipes, and other piping elements (e.g., pipe connections, tubes, seals, valves, etc.) for fluid communication between different units of interconnecting equipment for fluid flow between different components (e.g., pumps, compressors, fans, valves, pipes, etc.) can be configured to meet a specific plant layout design taking into account the available area of ​​the equipment, the size of the equipment, and other design considerations. As another example, the flow rate, pressure, and temperature of the fluid passing through one or more heat exchangers and other plant components can be varied to consider different plant design configurations and other design criteria. As yet another example, the number of plant units and their arrangement can be adjusted to meet a specific set of design criteria. As yet another example, the different structural components for the plant units and the material composition of the plant can be any type of suitable material that may be required to meet a specific set of design criteria.

[0094] As yet another example, embodiments of the liquefier 11, plant 1, heat exchanger equipment 10, and process can each be configured to include or utilize process control elements positioned and configured to monitor and control operation (e.g., temperature and pressure sensors, flow sensors, automated process control systems having at least one workstation including a processor, non-transient memory, and at least one transceiver for communicating with sensor elements, valves, and controllers to provide a user interface for the automated process control system, which may operate at the workstation and / or another computer device in the plant). It should be understood that embodiments can also utilize a distributed control system (DCS) to implement the operation of one or more processes and / or control equipment or processes.

[0095] As another example, it is contemplated that specific features described herein (individually or as part of an embodiment) may be combined with other individually described features or parts of other embodiments. Thus, elements and actions of the various embodiments described herein may be combined to provide further embodiments. Therefore, although certain exemplary embodiments of processes, apparatuses, systems, and methods of manufacture and use thereof have been shown and described above, it will be clearly understood that the invention is not limited thereto, but may be embodied and practiced differently in other ways within the scope of the following claims.

Claims

1. A process for operating a heat exchanger device, the process comprising: At least a first feed fluid is supplied to a heat exchanger device and at least a first refrigerant fluid is supplied to the heat exchanger device, while the plant process is operable to cool the first feed fluid and heat the first refrigerant fluid; In response to the shutdown of the plant process, the supply of the first feed fluid to the heat exchanger device and the supply of the first refrigerant fluid to the heat exchanger device are stopped, and at least one process flow is supplied to the heat exchanger device to maintain the temperature profile of the heat exchanger device when the plant process is shut down.

2. The process according to claim 1, wherein the at least one process flow comprises the vaporized vapor of a cryogenic liquid fluid stored in at least one storage tank.

3. The process according to claim 1, wherein the at least one process stream comprises separator evaporation steam.

4. The process according to claim 1, comprising: When the liquefier in the plant process is shut down, the at least one process flow is output from the heat exchanger device, and the at least one output process flow is recycled back to the heat exchanger device.

5. The process according to claim 1, comprising: When the liquefier in the plant process is shut down, the at least one process flow is output from the heat exchanger device; after the at least one process flow is output from the heat exchanger device, the at least one process flow is heated; and the at least one output process flow is recycled back to the heat exchanger device as at least one recirculated process flow.

6. The process according to claim 5, comprising: The heat exchanger device outputs at least one recirculation process stream to discharge the recirculation process stream.

7. The process of claim 5, wherein when the recirculated process gas is returned to the heat exchanger device, the recirculated process gas has a temperature between 0°C and 50°C.

8. The process of claim 1, wherein the at least one process flow comprises a refrigerant process flow at a temperature between -150°C and -200°C.

9. The process according to claim 1, wherein the first feed fluid is composed of nitrogen and / or oxygen, the first feed fluid is at a temperature between 0°C and 50°C, and the first refrigerant fluid is at a temperature between -150°C and -200°C.

10. The process according to claim 1, comprising: A regulating valve is used to supply the at least one process flow to the heat exchanger device to maintain the temperature profile of the heat exchanger device when the liquefier of the plant process is shut down.

11. The process of claim 10, wherein the at least one process stream comprises evaporated vapor of a cryogenic liquid fluid stored in at least one storage tank, a stream output from the tower assembly of an air separation unit (ASU), and / or evaporated gas from a separator.

12. A heat exchanger device, comprising: A first heat exchanger is fluidly connected to at least a first warm fluid feed line and a first refrigerant feed line, such that refrigerant can be supplied to the heat exchanger via the first refrigerant feed line to cool the feed fluid supplied to the heat exchanger via the first warm fluid feed line when the plant process utilizing the heat exchanger is operable. as well as A recirculation piping arrangement is configured to recirculate the process flow delivered to the first heat exchanger via the first refrigerant feed line when the plant process is shut down, in order to maintain the temperature profile of the heat exchanger equipment when the plant process is shut down.

13. The heat exchanger device of claim 12, wherein the recirculation piping arrangement includes a temperature difference control device.

14. The heat exchanger device according to claim 13, wherein the temperature difference control device is a heating device.

15. The heat exchanger device according to claim 13, wherein the temperature difference control device is a cooling device.

16. The heat exchanger apparatus of claim 11, wherein the plant process includes liquefying via a liquefaction device and the first refrigerant feed line is fluidly connected to the liquefaction device.

17. The heat exchanger device according to claim 11, comprising: A storage tank configured to store cryogenic liquid, the storage tank being fluidly connected to the first heat exchanger such that the vapors of the cryogenic liquid can be supplied to the first heat exchanger as the process flow.

18. The heat exchanger device according to claim 11, comprising: A separator, which is fluidly connected to the first heat exchanger, such that separator vapor gas from the separator can be supplied to the first heat exchanger as the process flow. or A tower assembly of an air separation unit (ASU) is fluidly connected to the first heat exchanger, so that the flow output from the tower assembly can be passed to the first heat exchanger as the process flow.

19. A factory comprising: A liquefaction device, comprising at least one liquefier and a heat exchanger device, the heat exchanger device being positioned upstream of the at least one liquefier and configured to liquefy a feed to be supplied to the at least one liquefier via at least one refrigerant output from the at least one liquefier during operation of the liquefaction device. The heat exchanger includes: A recirculation piping arrangement is positioned and configured such that a process flow can be supplied to the heat exchanger device to maintain the temperature profile of the heat exchanger device when the liquefaction device is shut down. The recirculation piping arrangement includes a temperature difference control device such that the process flow can be output from the heat exchanger device, its temperature regulated via the temperature difference control device, and subsequently recirculated to the heat exchanger device.

20. The plant of claim 19, wherein the temperature difference control device is configured such that the process flow can be output from the heat exchanger device, temperature regulated via the temperature difference control device, and subsequently recirculated to the heat exchanger device to simulate heat transfer occurring to cool the feed to be supplied to the at least one liquefier via the at least one refrigerant output from the at least one liquefier.

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