Transcritical refrigeration pressure exchanger

Abstract

The pressure exchanger (PX) comprises a rotor configured to receive a first fluid, receive a second fluid, and exchange pressure between the first fluid and the second fluid, the rotor forming a plurality of ducts. The PX further comprises a first end cover in fluid communication with the rotor, the first end cover forming a first kidney, the kidney angular range of the first kidney being substantially an integer multiple of a duct angular spacing between at least two adjacent ducts of the plurality of ducts, the kidney angular range being the angular distance between an open edge and a closed edge of the first kidney, and the duct angular spacing being the angular distance between corresponding centers of the at least two adjacent ducts.

Description

[Technical Field]

[0001] The present disclosure relates to pressure exchangers (PX), and more particularly to PXs used in refrigeration systems. [Background technology]

[0002] The system uses fluids at different pressures. The system uses components to increase the pressure of the fluids.

[0003] The present disclosure is illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings. [Brief explanation of the drawings]

[0004] [Figure 1A] FIG. 1A shows a schematic diagram of a fluid treatment system including a hydraulic energy transfer system, according to certain embodiments. [Figure 1B] FIG. 1B shows a schematic diagram of a fluid treatment system including a hydraulic energy transfer system, according to certain embodiments. [Figure 1C] FIG. 1C shows a schematic diagram of a fluid treatment system including a hydraulic energy transfer system, according to certain embodiments. [Figure 1D] FIG. 1D shows a schematic diagram of a fluid processing system including a hydraulic energy transfer system, according to certain embodiments. [Figure 2A] FIG. 2A is an exploded perspective view of a pressure exchanger (PX), according to some embodiments. [Figure 2B] FIG. 2B is an exploded perspective view of a pressure exchanger (PX), according to some embodiments. [Figure 2C] FIG. 2C is an exploded perspective view of a pressure exchanger (PX), according to some embodiments. [Figure 2D] FIG. 2D is an exploded perspective view of a pressure exchanger (PX), according to some embodiments. [Figure 2E] FIG. 2E is an exploded perspective view of a pressure exchanger (PX), according to some embodiments. [Figure 3A]FIG. 3A illustrates a PX including an end cover forming a kidney and a rotor forming a duct, according to some embodiments. [Figure 3B] FIG. 3B illustrates a PX including end covers forming kidneys and rotors forming ducts, according to some embodiments. [Figure 3C] FIG. 3C illustrates an end cover, according to some embodiments. [Figure 3D] FIG. 3D illustrates a seal plate, according to some embodiments. [Figure 4] FIG. 4 illustrates an end cover, according to some embodiments. [Figure 5] FIG. 5 illustrates an end cover, according to some embodiments. [Figure 6] FIG. 6 illustrates an end cover including a buffer chamber, according to some embodiments. [Figure 7A] FIG. 7A illustrates a PX with a rotor and end cover, according to some embodiments. [Figure 7B] FIG. 7B illustrates a PX with a rotor and end cover, according to some embodiments. [Figure 8A] FIG. 8A illustrates a PX with a rotor and end cover, according to some embodiments. [Figure 8B] FIG. 8B illustrates a PX with a rotor and end cover, according to some embodiments. [Figure 9] FIG. 9 illustrates a rotor forming a duct, according to some embodiments. [Figure 10] FIG. 10 illustrates an end cover forming a pre-compression hole, according to some embodiments. [Figure 11] FIG. 11 illustrates a spot face of an end cover, according to certain embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0005] The embodiments described herein relate to PX for transcritical refrigeration.

[0006] Systems can use fluids at different pressures. One supply of fluid to a system may be at a lower pressure, while one or more portions of the system operate at a higher pressure. Systems can include closed loops with various fluid pressures maintained in different portions of the loop. These systems can include hydraulic fracturing (e.g., fracking or fracing) systems, desalination systems, refrigeration systems, heat pump systems, energy generation systems, mud pump systems, slurry pump systems, industrial fluid systems, waste systems, fluid transport systems, etc. Pumps or compressors can be used to increase the pressure of fluids in such systems.

[0007] Traditionally, systems (e.g., refrigeration systems, heat pump systems, reversible heat pump systems, etc.) use pumps or compressors to increase the pressure of a fluid (e.g., refrigeration fluids such as carbon dioxide (CO), R-744, R-134a, hydrocarbons, hydrofluorocarbons (HFCs), hydrochlorofluorocarbons (HCFCs), ammonia (NH), refrigerant mixtures, R-407A, R-404A, etc.). Traditionally, a separate pump or compressor mechanically coupled to a motor is used to increase the fluid pressure in any portion of the system that involves increasing the fluid pressure. Pumps and compressors, especially those operating across a large pressure differential (e.g., causing a large pressure increase in the fluid), require a large amount of energy. Therefore, traditional systems consume a large amount of energy to increase the fluid pressure (via the pump or compressor driven by the motor). Additionally, traditional heat transfer systems reduce the fluid pressure through expansion valves, capillaries, or orifices. Traditional systems inefficiently increase and reduce the fluid pressure. This is wasteful in terms of the energy used to run conventional systems (e.g., the energy used to repeatedly increase the pressure of the refrigeration fluid and cause the temperature of the surrounding environment to increase or decrease). In some embodiments, the present disclosure relates to the design of a high-performance transcritical carbon dioxide (CO2) PX. The PX of the present disclosure can be used for transcritical CO2 refrigeration and / or heat pump applications.

[0008] The disclosed systems, apparatus, and methods provide a PX for use in a system (e.g., a fluid processing system, a heat transfer system, a refrigeration system, a heat pump system, a cooling system, a heating system, etc.). In the system, the PX may be configured to exchange pressure between a first fluid (e.g., a high-pressure portion of a refrigeration fluid in a refrigeration cycle) and a second fluid (e.g., a low-pressure portion of a refrigeration fluid in a refrigeration cycle). The PX may receive the first fluid (e.g., a portion of the refrigeration fluid that is at high pressure) via a first inlet (e.g., a high-pressure inlet) and the second fluid (e.g., a portion of the refrigeration fluid that is at low pressure) via a second inlet (e.g., a low-pressure inlet). When entering the PX, the first fluid may be at a higher pressure than the second fluid. The PX may exchange pressure between the first fluid and the second fluid. The first fluid may exit the PX via a first outlet (e.g., a low-pressure outlet), and the second fluid may exit the PX via a second outlet (e.g., a high-pressure outlet). Upon exiting the PX, the second fluid may have a higher pressure than the first fluid (e.g., pressure has been exchanged between the first and second fluids). The PX may be a rotary PX that exchanges pressure energy between two streams of a transcritical gas (e.g., CO2 in either the liquid phase, the gas phase, or a mixture of these two phases).

[0009] Some systems (e.g., PX-based heat transfer systems) may have high vibration levels at the input / output ports (e.g., of the PX) that exceed refrigeration compressor standards (e.g., ASHRAE (American Society of Heating, Refrigerating, and Air-Conditioning Engineers) standards). Some systems may also generate high noise levels that exceed the upper limits adhered to by most compressor equipment manufacturers. Some systems (e.g., PX-based systems) may not effectively reduce energy consumption due to various losses, namely, expansion losses, mixing losses, internal leakage losses, and pressure losses. Some systems (e.g., PX-based systems) may not effectively mitigate mixing, resulting in increased enthalpy dilution in the high-pressure kidney (HPOUT kidney) and a reduced liquid fraction in the low-pressure kidney (LPOUT kidney), reducing the energy savings of the PX. Some systems (e.g., PX-based systems) may experience high pressure drops across the PX (especially at high flow rates and RPMs), resulting in increased compressor work and reduced energy savings. Some systems (e.g., PX-based systems) may have higher leakage through the PX bearings, reducing coolant flow through the rotor and reducing energy recovery. Some systems (e.g., PX-based systems) may have a higher risk of cavitation, reducing bearing stiffness / load capacity.

[0010] The disclosed system can solve one or more of these and other problems. The disclosed system reduces wear on components (e.g., pumps, compressors) compared to conventional systems. The disclosed system reduces mixing in transcritical CO2 PX, resulting in reduced enthalpy dilution in the HPOUT and increased liquid fraction in the LPOUT compared to conventional systems, improving PX energy savings. The disclosed system reduces pressure drop across the PX (especially at higher flow rates and RPMs), resulting in reduced booster work and improved energy savings compared to conventional systems. The disclosed system reduces leakage through the PX bearings, allowing for increased refrigerant flow through the rotor, thereby increasing energy recovery compared to conventional systems (e.g., conventional PX-based systems). The disclosed system can reduce the risk of cavitation and enhance bearing stiffness / load capacity compared to conventional systems (e.g., conventional PX-based systems). The use of end covers with reduced thickness and elimination of carrier plates results in a shorter and stiffer drivetrain compared to conventional systems (e.g., conventional PX-based systems).

[0011] In some embodiments, the PX includes one or more of the features described in one or more of Figures 3A-11.

[0012] In some embodiments, the PX comprises a rotor configured to receive a first fluid, receive a second fluid, and exchange pressure between the first fluid and the second fluid. The rotor forms a plurality of ducts. The PX further comprises a first end cover in fluid communication with the rotor, the first end cover forming a first kidney, the kidney angle range of the first kidney being substantially an integer multiple of a duct angle spacing between at least two adjacent ducts of the plurality of ducts. In some embodiments, the kidney angle range is the angular distance between an open edge and a closed edge of the first kidney, and the duct angle spacing is the angular distance between corresponding centers of the at least two adjacent ducts.

[0013] In some embodiments, the PX includes a second end cover forming a second kidney, and the delay angle between the first kidney and the second kidney is in the range of 15 to 20 degrees. In some embodiments, the delay angle is the angular distance between the closed edge of the second kidney and the closed edge of the first kidney. In some embodiments, a similar delay opening may be present in the first kidney within the second end cover. In some embodiments, a similar delay opening may be present in the third kidney formed by the first end cover and the fourth kidney formed by the second end cover.

[0014] In some embodiments, the rotor forms ducts in multiple concentric rows, with the ducts in two rows being staggered.

[0015] In some embodiments, the PX includes a second end cover, the second end cover forming a second kidney. In some embodiments, the second kidney may have a delay opening relative to the first kidney formed by the first end cover. The first end cover has a first end cover surface facing the rotor, the first end cover surface forming a buffer chamber disposed in a delay region of the first end cover. In some embodiments, the delay region is a region between an open edge of the second kidney and an open edge of the first kidney.

[0016] In some embodiments, the first end cover forms a third kidney. In some embodiments, fluid flow between the PX port and the rotor passes through the first kidney and the third kidney. In some embodiments, the ratio of the size of the first kidney to the size of the third kidney is in the range of 3:2 to 5:2.

[0017] In some embodiments, the PX includes a rotor configured to receive a first fluid, receive a second fluid, and exchange pressure between the first fluid and the second fluid. In some embodiments, the rotor forms a plurality of ducts. The pressure exchanger further includes a first end cover fluidly connected to the rotor, the first end cover having a first end cover surface facing the rotor. The first end cover surface forms a buffer chamber disposed within a delay region of the first end cover. In some embodiments, the PX includes a second end cover forming a second kidney, the delay region being a region between an open edge of the second kidney and an open edge of the first kidney.

[0018] In some embodiments, the PX further comprises a second end cover in fluid communication with the rotor, the second end cover forming a third kidney, and in some embodiments, when a first duct of the plurality of ducts is substantially aligned with the buffer chamber, the third kidney is substantially aligned with the first duct.

[0019] In some embodiments, a first duct and a second duct of the plurality of ducts are simultaneously substantially aligned with the buffer chamber, while the third kidney is substantially aligned with the first duct.

[0020] In some embodiments, the third kidney is a high pressure out (HPOUT) kidney, and the first duct and the second duct are low pressure ducts.

[0021] In some embodiments, the first kidney is a high pressure in (HPIN) kidney, and the first duct is substantially aligned with the first kidney after being aligned with the buffer chamber.

[0022] In some embodiments, the third kidney is a low pressure out (LPOUT) kidney, and the first duct and the second duct are high pressure ducts.

[0023] In some embodiments, the first kidney is a low pressure in (LPin) kidney, and the first duct is substantially aligned with the first kidney after being aligned with the buffer chamber.

[0024] In some embodiments, the kidney angle range of the first kidney is substantially an integer multiple of the duct angle spacing between at least two adjacent ducts of the plurality of ducts, hi some embodiments, the kidney angle range is the angular distance between the open edge and the closed edge of the first kidney, and the duct angle spacing is the angular distance between corresponding centers of the at least two adjacent ducts.

[0025] In some embodiments, the buffer chamber is substantially similar in shape to the first kidney and has an angular extent equal to or substantially twice the angular extent of one of the rotor ducts.

[0026] In some embodiments, the first end cover forms a third kidney. In some embodiments, fluid flow between the PX port and the rotor passes through the first kidney and the third kidney. In some embodiments, the ratio of the size of the first kidney to the size of the second kidney is in the range of 3:2 to 5:2.

[0027] In some embodiments, the PX comprises a rotor configured to receive a first fluid, receive a second fluid, and exchange pressure between the first and second fluids. The PX further comprises a first end cover in fluid communication with the rotor, the first end cover defining a first kidney and a second kidney. In some embodiments, fluid flow between a port of the PX and the rotor passes through the first kidney and the second kidney. In some embodiments, the ratio of the size of the first kidney to the size of the second kidney is in the range of 3:2 to 5:2.

[0028] In some embodiments, the first kidney is a high-pressure kidney and the second kidney is a low-pressure kidney.

[0029] In some embodiments, the PX further comprises a second end cover in fluid communication with the rotor, the second end cover defining a third kidney and a fourth kidney. In some embodiments, fluid flow between the port of the PX and the rotor passes through the third kidney and the fourth kidney. In some embodiments, the ratio of the size of the third kidney to the size of the fourth kidney is in the range of 3:2 to 5:2.

[0030] In some embodiments, the third kidney is a high-pressure kidney and the fourth kidney is a low-pressure kidney.

[0031] In some embodiments, the rotor forms a plurality of ducts. In some embodiments, a kidney angle range of the first kidney is substantially an integer multiple of a duct angle range between at least two adjacent ducts of the plurality of ducts. In some embodiments, the rotor forms a plurality of ducts. In some embodiments, a kidney angle range of the first kidney is substantially an integer multiple of an angular spacing between at least two adjacent ducts of the plurality of ducts. In some embodiments, the kidney angle range is an angular distance between an open edge and a closed edge of the first kidney, and the duct angular spacing is an angular distance between corresponding centers of the at least two adjacent ducts.

[0032] The disclosed systems, apparatus, and methods offer advantages over conventional solutions. The disclosed systems reduce energy consumption compared to conventional systems. For example, the use of the disclosed PX can recover energy stored as pressure and return that energy to the system, reducing the energy costs of operating the system. The disclosed systems reduce mixing in transcritical CO2 PX, resulting in reduced enthalpy dilution in the HPOUT and increased liquid fraction in the LPOUT compared to conventional systems, improving PX energy savings. The disclosed systems reduce pressure drop across the PX (especially at higher flow rates and RPMs), resulting in reduced booster work and improved energy savings compared to conventional systems. The disclosed systems reduce leakage through PX bearings and allow for increased coolant flow through the rotor, increasing energy recovery compared to conventional systems. The disclosed systems can reduce the risk of cavitation and increase bearing stiffness / load capacity compared to conventional systems. The use of end covers with reduced thickness and elimination of carrier plates results in a shorter and stiffer drivetrain compared to conventional systems.

[0033] Although some embodiments of the present disclosure are described in relation to PXs, energy recovery devices, and hydraulic energy transmission systems, the present disclosure may be applied to other systems and devices (e.g., non-isobaric PXs, non-PX rotating components, non-rotating PXs, systems that do not include a PX, etc.).

[0034] Although some embodiments of the present disclosure are described in connection with exchanging pressure between fluids used in fracing systems, desalination systems, heat pump systems, and / or refrigeration systems, the present disclosure may also be applied to other types of systems. Fluids may refer to liquids, gases, transcritical fluids, supercritical fluids, subcritical fluids, and / or combinations thereof.

[0035] 1A-D show schematic diagrams of a fluid treatment system 100 including a hydraulic energy transfer system 110, according to certain embodiments.

[0036] In some embodiments, hydraulic energy transmission system 110 includes a PX (e.g., PX). The PX may include one or more of the features described in one or more of Figures 3A-11.

[0037] The hydraulic energy transfer system 110 (e.g., PX) receives a low pressure (LP) in fluid 120 (e.g., a low pressure inlet flow) from an LP in system 122. The hydraulic energy transfer system 110 also receives a high pressure (HP) in fluid 130 (e.g., a high pressure inlet flow) from an HP in system 132. The hydraulic energy transfer system 110 (e.g., PX) exchanges pressure between the HP in fluid 130 and the LP in fluid 120 to provide an LP out fluid 140 (e.g., a low pressure outlet flow) to an LP out fluid system 142 and an HP out fluid 150 (e.g., a high pressure outlet flow) to an HP out fluid system 152.

[0038] In some embodiments, the hydraulic energy transmission system 110 includes a PX that exchanges pressure between the HP in fluid 130 and the LP in fluid 120. The PX can be a device that transfers fluid pressure between the HP in fluid 130 and the LP in fluid 120 with greater than about 50%, 60%, 70%, 80%, 90% efficiency or greater (e.g., without utilizing centrifugal techniques). High pressure (e.g., HP in fluid 130, HP out fluid 150) refers to a pressure greater than low pressure (e.g., LP in fluid 120, LP out fluid 140). The LP in fluid 120 at the PX can be pressurized and exit the PX at a high pressure (e.g., HP out fluid 150, which is a pressure greater than the LP in fluid 120), and the HP in fluid 130 can be depressurized and exit the PX at a low pressure (e.g., LP out fluid 140, which is a pressure lower than the HP in fluid 130). The PX may operate using the HPin fluid 130 to directly apply a force to pressurize the LIn fluid 120, with or without a fluid separator between the fluids. Examples of fluid separators that may be used with the PX include, but are not limited to, pistons, bladders, diaphragms, and the like. In some embodiments, the PX may be a rotary device. Rotary PXs, such as those manufactured by Energy Recovery Inc. of San Leandro, California, may not have isolation valves because effective valving is achieved internally through the relative motion of the rotor with respect to the end cover. Rotary PXs may also operate with internal pistons that isolate the fluids and are designed to exchange pressure with relatively little mixing of the inlet fluid streams. Reciprocating PXs may include pistons that move back and forth within a cylinder to transfer pressure between the fluid streams. For example, but not limited to, a rotary PX, a reciprocating PX, or a combination thereof, or multiple PXs may be used in the present disclosure. Additionally, the PX may be located on a skid that is separate from the other components of fluid treatment system 100 (eg, in situations where the PX is being added to an existing fluid treatment system).

[0039] In some embodiments, motor 160 is coupled to hydraulic energy transmission system 110 (e.g., to PX). In some embodiments, motor 160 controls the speed of a rotor of hydraulic energy transmission system 110 (e.g., to increase the pressure of HPout fluid 150 or decrease the pressure of HPin fluid 130). In some embodiments, motor 160 generates energy (e.g., acts as a generator) based on pressure exchange within hydraulic energy transmission system 110.

[0040] Hydraulic energy transfer system 110 may be a hydraulic protection system (e.g., hydraulic buffer system, hydraulic separation system) that exchanges work and / or pressure with other fluids while insulating or limiting contact between solid particle-laden fluids (e.g., fracking fluids) and various equipment (e.g., hydraulic fracturing equipment, high-pressure pumps). By insulating or limiting contact between solid particle-laden fluids and various equipment (e.g., fracturing equipment), hydraulic energy transfer system 110 improves the life and performance of various equipment (e.g., fracturing equipment, high-pressure fluid pumps) while reducing wear and tear. Using equipment (e.g., high-pressure fluid pumps) that is not designed for abrasive fluids (e.g., fracking fluids and / or corrosive fluids) may reduce the cost of equipment that may be used in fluid treatment system 100.

[0041] The hydraulic energy transfer system 110 may include a hydraulic turbocharger or hydraulic exchange system, such as a rotary PX. The PX may include one or more chambers (e.g., 1-100) that facilitate pressure transfer and equalization between a volume of a first fluid and a second fluid (e.g., gas, liquid, multiphase fluid). In some embodiments, the PX may transfer pressure between a first fluid (e.g., a pressure exchange fluid, such as a proppant-free or substantially proppant-free fluid) and a second fluid that may be highly viscous and / or contain solid particles (e.g., sand, proppant, powder, debris, ceramic-containing fracking fluid). Solid particle-containing fluids cause wear and / or erosion of PX components, such as the rotor and end covers of the PX. Fluids (e.g., abrasive particles within the fluid) can cause wear at the interface between the rotor and each end cover as the rotor rotates relative to the end cover. Replacing worn PX components can be costly.

[0042] The hydraulic energy transfer system 110 may be used in various types of systems, such as fracing systems, desalination systems, and refrigeration systems.

[0043] 1A shows a schematic diagram of a fluid treatment system 100A including a hydraulic energy transfer system 110, according to certain embodiments. The fluid treatment system 100A may include a control module 180 including one or more controllers 185.

[0044] 1B shows a schematic diagram of a fluid treatment system 100B including a hydraulic energy transfer system 110, according to certain embodiments. Fluid treatment system 100B may be a frating system. In some embodiments, fluid treatment system 100B includes more components, fewer components, the same routing, different routing, and / or the like than those shown in FIG. 1B.

[0045] The LPin fluid 120 and the HPout fluid may be fracking fluids (e.g., solid particle-containing fluids, proppant-containing fluids). The HPin fluid 130 and the LPout fluid 140 may be fluids that are substantially free of solid particles (e.g., proppant-free fluids, water, filtered fluids, etc.).

[0046] The LPin system 122 may include one or more low-pressure fluid pumps for supplying the LPin fluid 120 to the hydraulic energy transmission system 110 (e.g., PX). The HPin system 132 may include one or more high-pressure fluid pumps 134 for supplying the HPin fluid 130 to the hydraulic energy transmission system 110.

[0047] A hydraulic energy transfer system 110 exchanges pressure between LPin fluid 120 (e.g., low-pressure fracking fluid) and HPin fluid 130 (e.g., high-pressure water) to supply HPout fluid 150 (e.g., high-pressure fracking fluid) to an HPout system 152, which supplies LPout fluid 140 (e.g., low-pressure water). The HPout system 152 may include a rock formation 154 (e.g., a well) that includes cracks 156. Solid particles (e.g., proppant) from the HPout fluid 150 may be supplied into the cracks 156 in the rock formation.

[0048] In some embodiments, the LPout fluid 140, the high-pressure fluid pump 134, and the HPin fluid 130 are part of a first loop (e.g., a proppant-free fluid loop). The LPout fluid 140 may be fed to the high-pressure fluid pump to produce the HPin fluid 130, which becomes the LPout fluid 140 upon exiting the hydraulic energy transfer system 110.

[0049] In some embodiments, the LPin fluid 120, the HPout fluid 150, and the low-pressure fluid pump 124 are part of a second loop (e.g., a proppant-containing fluid loop). The HPout fluid 150 may be fed into the rock formation 154 and then pumped out of the rock formation 154 by the low-pressure fluid pump 124 to produce the LPin fluid 120.

[0050] In some embodiments, the fluid treatment system 100B is used in well completion operations in the oil and gas industry to perform hydraulic fracturing (e.g., fracking or fracing) to enhance the release of oil and gas within a rock formation 154. An HPout system 152 may include a rock formation 154 (e.g., a well). Hydraulic fracturing may include pumping an HPout fluid 150, including a combination of water, chemicals, and solid particles (e.g., sand, ceramic, proppant), at high pressure into the well (e.g., rock formation 154). The LPin fluid 120 and the HPout fluid 150 may include fluids containing particles that enhance the release of oil and gas within the rock formation 154 by propagating and increasing the size of cracks 156 within the rock formation 154. The high pressure of the HPout fluid 150 causes cracks 156 to initiate, expand in size, and propagate through the rock formations 154, releasing more oil and gas, while solid particles (e.g., powder, debris, etc.) enter the cracks 156, keeping them open (e.g., preventing them from closing once the HPout fluid 150 is depressurized).

[0051] To pump this particle-laden fluid into the rock formation 154 (e.g., a well), fluid treatment system 100B may include one or more high-pressure fluid pumps 134 and one or more low-pressure fluid pumps 124 coupled to hydraulic energy transfer system 110. For example, hydraulic energy transfer system 110 may be a hydraulic turbocharger or PX (e.g., a rotary PX). In operation, hydraulic energy transfer system 110 transfers pressure without any substantial mixing between a first fluid (e.g., HPin fluid 130, proppant-free fluid) pumped by high-pressure fluid pump 134 and a second fluid (e.g., LPin fluid 120, proppant-bearing fluid, fracking fluid) pumped by low-pressure fluid pump 124. In this manner, hydraulic energy transfer system 110 prevents or limits wear on high-pressure fluid pump 134 while simultaneously enabling fluid treatment system 100B to pump high-pressure fracking fluid (e.g., HPout fluid 150) into the rock formation 154 to release oil and gas. To operate in a corrosive and abrasive environment, hydraulic energy transmission system 110 may be constructed from materials that are resistant to the corrosive and abrasive substances contained in either the first or second fluid. For example, hydraulic energy transmission system 110 may be constructed from a ceramic (e.g., a cermet such as alumina, carbide, oxide, nitride, or boride hard phase) in a metal matrix (e.g., Co, Cr, or Ni, or any combination thereof), such as tungsten carbide in a matrix of CoCr, Ni, NiCr, or Co.

[0052] In some embodiments, hydraulic energy transfer system 110 includes a PX (e.g., a rotary PX) where an HPin fluid 130 (e.g., a first fluid, a high-pressure, solid-particle-free fluid) enters a first side of the PX. Here, the HPin fluid 130 contacts an LPin fluid 120 (e.g., a second fluid, a low-pressure fracking fluid) entering the PX on a second side. The contact between the fluids allows the HPin fluid 130 to increase the pressure of the second fluid (e.g., LPin fluid 120), which then pushes a second out fluid (e.g., HPout fluid 150) out of the PX and into a well (e.g., rock formation 154) for fracturing operations. The first fluid (e.g., LPout fluid 140) also exits the PX, but at a lower pressure after exchanging pressure with the second fluid. As previously mentioned, the second fluid may be a low-pressure fracking fluid that may contain abrasive particles that may wear away the interface between the rotor and each end cover as the rotor rotates relative to each end cover.

[0053] 1C shows a schematic diagram of a fluid treatment system 100C including a hydraulic energy transfer system 110, according to certain embodiments. Fluid treatment system 100C may be a desalination system (e.g., removing salt and / or other minerals from water). In some embodiments, fluid treatment system 100C includes more components, fewer components, the same routing, different routing, etc. than those shown in FIG. 1C.

[0054] The LPin system 122 may include a feed pump 126 (e.g., low-pressure fluid pump 124) that receives in seawater 170 (e.g., a reservoir feed or a direct ocean feed) and supplies the LPin fluid 120 (e.g., low-pressure seawater, feedwater) to the hydraulic energy transmission system 110 (e.g., the PX). The HPin system 132 may include a membrane 136 that supplies the HPin fluid 130 (e.g., high-pressure brine) to the hydraulic energy transmission system 110 (e.g., the PX). The hydraulic energy transmission system 110 exchanges pressure between the HPin fluid 130 and the LPin fluid 120 to supply the HPout fluid 150 (e.g., high-pressure seawater) to the HPout system 152 and the LPout fluid 140 (e.g., low-pressure brine) to the LPout system 142 (e.g., a geological mass, ocean, sea, wastewater, etc.).

[0055] Membrane 136 may be a membrane separator configured to separate fluids passing through the membrane, such as a reverse osmosis membrane. Membrane 136 may provide concentrated feedwater or concentrate (e.g., brine) HPin fluid 130 to hydraulic energy transfer system 110. The pressure of HPin fluid 130 may be used to compress low-pressure feedwater (e.g., LPin fluid 120) into high-pressure feedwater (e.g., HPout fluid 150). For simplicity and descriptive purposes, the term feedwater is used. However, fluids other than water may be used in hydraulic energy transfer system 110.

[0056] A circulation pump 158 (e.g., a turbine) delivers HPout fluid 150 (e.g., high-pressure seawater) to membrane 136. Membrane 136 filters HPout fluid 150 to deliver LP potable water 172 and HPin fluid 130 (e.g., high-pressure brine). LPout system 142 delivers out brine 174 (e.g., to a geological mass, ocean, sea, waste, etc.).

[0057] In some embodiments, a high-pressure fluid pump 176 is disposed between the feedwater pump 126 and the membrane 136. The high-pressure fluid pump 176 increases the pressure of the low-pressure seawater (e.g., LPin fluid 120, providing the high-pressure feedwater) that is mixed with the high-pressure seawater provided by the circulation pump 158.

[0058] In some embodiments, use of hydraulic energy transfer system 110 reduces the load on high-pressure fluid pump 176. In some embodiments, fluid treatment system 100C provides LP potable water 172 without using high-pressure fluid pump 176. In some embodiments, fluid treatment system 100C provides LP potable water 172 using high-pressure fluid pump 176 intermittently.

[0059] In some examples, hydraulic energy transfer system 110 (e.g., PX) receives LPin fluid 120 (e.g., low-pressure feedwater) at approximately 30 pounds per square inch (PSI) (approximately 207 kPa) and HPin fluid 130 (e.g., high-pressure brine or concentrate) at approximately 980 PSI (approximately 6757 kPa). Hydraulic energy transfer system 110 (e.g., PX) transfers pressure from the high-pressure concentrate (e.g., HPin fluid 130) to the low-pressure feedwater (e.g., LPin fluid 120). Hydraulic energy transfer system 110 (e.g., PX) outputs HPout fluid 150 (e.g., high-pressure (compressed) feedwater) at approximately 965 PSI (approximately 6653 kPa) and outputs LPout fluid 140 (e.g., low-pressure concentrate) at approximately 15 PSI (approximately 103 kPa). Thus, the hydraulic energy transmission system 110 (e.g., PX) can be approximately 97% efficient because the input volume is approximately equal to the output volume of the hydraulic energy transmission system 110 (e.g., PX), and 965 PSI (approximately 6653 kPa) is approximately 97% of 980 PSI (approximately 6757 kPa).

[0060] Figure 1D shows a schematic diagram of a fluid treatment system 100D including a hydraulic energy transfer system 110, according to certain embodiments. Fluid treatment system 100D may be a refrigeration system. In some embodiments, fluid treatment system 100D includes more components, fewer components, the same routing, different routing, etc. than those shown in Figure 1D.

[0061] A hydraulic energy transfer system 110 (e.g., PX) receives LPin fluid 120 from an LPin system 122 (e.g., low-pressure lift device 128, low-pressure fluid pump, etc.) and receives HPin fluid 130 from an HPin system 132 (e.g., condenser 138). The hydraulic energy transfer system 110 (e.g., PX) may exchange pressure between the LPin fluid 120 and the HPin fluid 130 to supply HPout fluid 150 to the HPout system 152 (e.g., high-pressure lift device 159) and supply LPout fluid 140 to the LPout system 142 (e.g., evaporator 144). The evaporator 144 may supply fluid to a compressor 178 and low-pressure lift device 128. The condenser 138 may receive fluid from the compressor 178 and high-pressure lift device 159.

[0062] Fluid treatment system 100D may be a closed system. LPin fluid 120, HPin fluid 130, LPout fluid 140, and HPout fluid 150 may all be fluids (e.g., refrigerants) that circulate in the closed system of fluid treatment system 100D.

[0063] In some embodiments, the fluid in the fluid treatment system 100D may contain solid particles. For example, solid particles (e.g., solid particles from welding) may be entrained in the fluid in the fluid treatment system 100D due to piping, equipment, connections (e.g., pipe welding, pipe soldering), etc. Solid particles in the fluid and / or high pressure of the fluid may cause wear and / or erosion of the PX components (e.g., rotors, end covers) of the hydraulic energy transfer system 110.

[0064] 2A-2E are exploded perspective views of a rotary PX 40 (eg, rotary PX, rotary liquid piston compressor (LPC)) according to certain embodiments. The PX 40 may include a motor 92 and / or a control module 94.

[0065] In some embodiments, PX 40 comprises one or more of the features described in one or more of Figures 3A-11.

[0066] The PX 40 is configured to transfer pressure and / or work between a first fluid (e.g., proppant-free fluid or supercritical carbon dioxide, HPin fluid 130) and a second fluid (e.g., fracking fluid or superheated carbon dioxide gas, LPin fluid 120) with minimal fluid mixing. The rotary PX 40 may include a generally cylindrical body portion 42 including a sleeve 44 (e.g., rotor sleeve) and a rotor 46. The rotary PX 40 may also include two end caps 48 and 50 including manifolds 52 and 54, respectively. The manifold 52 includes a respective inlet port 56 and outlet port 58, and the manifold 54 includes a respective inlet port 60 and outlet port 62. During operation, the inlet ports 56, 60 allow the first and second fluids to enter the rotary PX 40 and exchange pressure, while the outlet ports 58, 62 allow the first and second fluids to exit the rotary PX 40. In operation, inlet port 56 may receive a high-pressure first fluid (e.g., HPin fluid 130) and, after exchanging pressure, outlet port 58 may be used to deliver a low-pressure first fluid (e.g., LPout fluid 140) from rotary PX 40. Similarly, inlet port 60 may receive a low-pressure second fluid (e.g., LPin fluid 120) and outlet port 62 may be used to deliver a high-pressure second fluid (e.g., HPout fluid 150) from rotary PX 40. End caps 48 and 50 are disposed within respective manifolds 52 and 54 and include respective end covers 64 and 66 (e.g., end plates) that enable fluid-tight contact with rotor 46.

[0067] As noted above, one or more components of PX 40, such as rotor 46, end cover 64, and / or end cover 66, may be constructed from a wear-resistant material (e.g., carbide, cemented carbide, silicon carbide, tungsten carbide, etc.) having a hardness greater than a predetermined threshold (e.g., a Vickers hardness number of at least 1000, 1250, 1500, 1750, 2000, 2250, or greater). For example, tungsten carbide may be more durable and provide improved wear resistance to abrasive fluids compared to other materials, such as alumina ceramic.

[0068] The rotor 46 may be cylindrical and disposed within the sleeve 44, allowing the rotor 46 to rotate about an axis 68. The rotor 46 may have a plurality of channels 70 (e.g., ducts, rotor ducts) extending generally longitudinally therethrough, with openings 72 and 74 (e.g., rotor ports) at each end symmetrically disposed about the longitudinal axis 68. The openings 72 and 74 in the rotor 46 are positioned to be in fluid communication with inlet apertures 76 and outlet apertures 78 (e.g., end cover inlet ports and end cover outlet ports) and 80 and 82 (e.g., end cover inlet ports and end cover outlet ports) in the end covers 64 and 66, respectively, such that the channels 70 are exposed to high-pressure and low-pressure fluids during rotation. As shown, the inlet apertures 76 and outlet apertures 78, 80, and 82 may be designed in the shape of an arc or a portion of a circle (e.g., C-shaped).

[0069] In some embodiments, a controller using sensor feedback (e.g., revolutions per minute measured via a tachometer or optical encoder, or volumetric flow rate measured via a flow meter) may control the degree of mixing of the first and second fluids within the rotary PX 40. This controller may be used to improve the operability of a fluid treatment system (e.g., fluid treatment systems 100A-100D of FIGS. 1A-1D). For example, by varying the volumetric flow rates of the first and second fluids entering the rotary PX 40, a plant operator (e.g., a system operator) can control the amount of fluid mixing within the PX 40. Additionally, by varying the rotational speed of the rotor 46, the operator can also control mixing. Three characteristics of the rotary PX 40 that affect mixing include (1) the aspect ratio of the rotor channel 70, (2) the exposure time between the first and second fluids, and (3) the creation of a fluid barrier (e.g., an interface) between the first and second fluids within the rotor channel 70. First, the rotor channel 70 (e.g., a duct) is generally long and narrow, stabilizing the flow within the rotary PX 40. Furthermore, the first and second fluids may move through the channel 70 in a plug-flow manner, minimizing axial mixing. Second, in certain embodiments, the speed of the rotor 46 reduces contact between the first and second fluids. For example, the speed of the rotor 46 (e.g., a rotor speed of about 1200 RPM) may reduce the contact time between the first and second fluids to less than about 0.15 seconds, 0.10 seconds, or 0.05 seconds. Third, a small portion of the rotor channel 70 is used to exchange pressure between the first and second fluids. This leaves a certain amount of fluid within the channel 70 as a barrier between the first and second fluids. Both of these mechanisms can limit mixing within the rotary PX 40. Additionally, in some embodiments, the rotary PX40 may be designed to operate with all or part of an internal piston or other barrier that separates the first and second fluids while still allowing pressure transmission.

[0070] 2B-2E are exploded views of one embodiment of the rotary PX 40, illustrating the sequence of positions of a single rotor channel 70 within the rotor 46 as the channel 70 rotates through one complete cycle. Note that FIGS. 2B-2E are simplified diagrams of the rotary PX 40, illustrating one rotor channel 70, and depicting the channel 70 as having a circular cross-sectional shape. In other embodiments, the rotary PX 40 may include multiple channels 70 having the same or different cross-sectional shapes (e.g., circular, oval, square, rectangular, polygonal, etc.). Therefore, FIGS. 2B-2E are simplified for illustrative purposes, and other embodiments of the rotary PX 40 may have configurations different from those shown in FIGS. 2A-2E. As described in more detail below, the rotary PX 40 facilitates pressure exchange between a first fluid and a second fluid by allowing the first and second fluids to briefly come into contact with each other within the rotor 46. In certain embodiments, this exchange occurs at a rate that limits mixing of the first and second fluids. The speed of the pressure wave passing through rotor channel 70 (as soon as the channel is exposed to aperture 76), the rate of diffusion of the fluids, and the rotational speed of rotor 46 determine whether and to what extent mixing occurs.

[0071] FIG. 2B is an exploded perspective view of one embodiment of a rotary PX 40 (e.g., a rotary LPC) according to certain embodiments. In FIG. 2B, the channel opening 72 is in a first position. In the first position, the channel opening 72 is in fluid communication with an aperture 78 in the end cover 64 and thus with the manifold 52, while the opposite channel opening 74 is in fluid communication with an aperture 82 in the end cover 66 and extends therefrom to be in fluid communication with the manifold 54. As discussed below, the rotor 46 may rotate in a clockwise direction, as indicated by arrow 84. During operation, a low-pressure second fluid 86 passes through the end cover 66 and into the channel 70, where it contacts the first fluid 88 at a dynamic fluid interface 90. The second fluid 86 then pushes the first fluid 88 from the channel 70, through the end cover 64, and out of the rotary PX 40. However, due to the short contact time, mixing between the second fluid 86 and the first fluid 88 is minimal.

[0072] 2C is an exploded perspective view of one embodiment of a rotating PX 40 (e.g., a rotating LPC) in accordance with certain embodiments. In FIG. 2C, channel 70 has been rotated clockwise through an arc of approximately 90 degrees. In this position, opening 74 (e.g., outlet) is not in fluid communication with apertures 80 and 82 in end cover 66, and opening 72 is not in fluid communication with apertures 76 and 78 in end cover 64. Thus, a low-pressure second fluid 86 is temporarily contained within channel 70.

[0073] 2D is an exploded perspective view of one embodiment of a rotary PX 40 (e.g., a rotary LPC) according to certain embodiments. In FIG. 2D, the channel 70 has been rotated through an arc of approximately 60 degrees from the position shown in FIG. 2B. The opening 74 is now in fluid communication with the aperture 80 in the end cover 66, and the opening 72 in the channel 70 is now in fluid communication with the aperture 76 in the end cover 64. In this position, a first fluid 88 at high pressure flows in and pressurizes a second fluid 86 at low pressure, forcing the second fluid 86 out of the rotor channel 70 through the aperture 80.

[0074] 2E is an exploded perspective view of one embodiment of a rotary PX 40 (e.g., a rotary LPC) in accordance with certain embodiments. In FIG. 2E, channel 70 has rotated through an arc of approximately 270 degrees from the position shown in FIG. 2B. In this position, opening 74 is no longer in fluid communication with apertures 80 and 82 in end cover 66, and opening 72 is no longer in fluid communication with apertures 76 and 78 in end cover 64. As a result, first fluid 88 is no longer pressurized and is temporarily retained within channel 70 until rotor 46 rotates another 90 degrees and the cycle begins again.

[0075] Abrasion and / or erosion damage in the PX can occur when suspended matter is introduced into and mixed with the fluid entering the PX. Abrasion damage can occur when particles enter gaps within the PX (e.g., become trapped between the stationary and rotating end covers). Erosion damage can occur due to the presence of suspended matter (e.g., erodents) in high-velocity fluid jets (e.g., slurry jets) created by high pressure differentials inside the PX. When high-velocity jets impact PX components, they can damage those components. Damage (e.g., erosion damage) can occur when high-pressure rotor ports (e.g., rotor ducts) open against low-pressure end cover ports (e.g., kidneys), or when low-pressure rotor ports (e.g., rotor ducts) open against high-pressure end cover ports (e.g., kidneys), causing a high pressure differential.

[0076] The PX of the present disclosure may have lower vibration levels (e.g., within ASHRAE standards for refrigeration compressors) at the HPIN, HPOUT, and LPOUT ports compared to conventional systems. The PX of the present disclosure may have lower noise levels (e.g., within the upper limits adhered to by compressor manufacturers) compared to conventional systems. The PX of the present disclosure may reduce mixing in transcritical CO2 PXs, which may result in reduced enthalpy dilution at the HPOUT and increased liquid fraction at the LPOUT, which may improve the energy savings of the PX. The present disclosure may reduce pressure drop across the PX (e.g., at higher flow rates and RPMs), which may result in reduced booster work and improved energy savings. The present disclosure may reduce leakage through PX bearings, thereby allowing for increased refrigerant flow through the rotor and increased energy recovery. The present disclosure may reduce the risk of cavitation and improve bearing stiffness and / or load capacity (e.g., of the PX). The present disclosure may reduce the thickness of end covers and shrink or eliminate carrier plates, resulting in a shorter and stiffer drivetrain and improved performance. The present disclosure can be mated with a housing (eg, a redesigned housing) that allows for increased HPOUT flow rates, reducing the chance of oil separation and accumulation in the PX.

[0077] In some embodiments, the present disclosure includes a device (rotary PX) that exchanges pressure energy between two streams of CO2, either in the liquid phase, the gas phase, or a mixture of these two phases.

[0078] 3A-B illustrate a PX including end covers forming kidneys and rotors forming ducts, according to some embodiments.

[0079] In some embodiments, at least one of the H, HP, L, or LP kidney angular extents (e.g., the angular distance between the open and closed edges of the kidney) can be an integer multiple of the duct angular extent (e.g., the spacing between adjacent ducts). In some embodiments, the angular extent can be a measure of angular size or magnitude, typically expressed in degrees, radians, or other angular units, describing the amount of rotation or separation between two lines or rays that share a common vertex (e.g., the open and closed edges of the kidney). For example, given a circle (e.g., an end cover), the angular extent of a sector (a portion of the circle) is measured in degrees or radians and represents the angle formed by the two radii that define the sector. A full circle has an angular extent of 360 degrees (or 2π radians). If a sector covers only a portion of a full circle, its angular extent is a fraction of 360 degrees (or 2π radians), depending on the portion of the circle it represents. In some embodiments, angular distance, when referring to a circle, may be a measure of the angle formed by two lines (or rays) that have their origin at the center of the circle and extend to two different points on the circumference of the circle. This angle, typically measured in degrees or radians, indicates how far apart two points are when moving from one point to the other along the edge of the circle.

[0080] Additionally, in some embodiments, an integer multiple may refer to an integer multiple, a non-negative whole-number multiple, etc. Mathematically, an integer may be a non-negative integer. When a first integer is multiplied by a second integer, the result is also an integer. When a first integer is multiplied by a second integer, the resulting product is said to be an integer multiple of both the first and second integers. For example, 21 is an integer multiple of both 7 and 3. In some embodiments, the duct angle interval may be 30 degrees. The HPIN kidney angle range in such a case may be an integer multiple of 30. For example, the HPIN kidney angle range may be 60 degrees, 90 degrees, 120 degrees, 150 degrees, 180 degrees, 210 degrees, etc.

[0081] In some embodiments, the spacing between the ducts may be uniform for all ducts. By using a kidney angle range that is an integer multiple of the spacing between the ducts (e.g., the duct angle spacing), when one duct begins to overlap the kidney, simultaneously another duct begins to leave the kidney (e.g., begin to cease overlapping). This makes the duct area of ​​the rotor ducts opening to the kidney (e.g., overlapping) substantially constant at substantially all times. The PX inlet may receive fluid from a positive displacement compressor (e.g., with a constant volumetric flow rate), and any variation in the duct area opening to the kidney (e.g., overlapping) results in acceleration and deceleration of the flow rate and corresponding unwanted pressure fluctuations. In some embodiments, the PX of the present disclosure includes a duct area of ​​the rotor duct opening to the kidney of the end cover that is substantially constant (e.g., by using a kidney angle range that is an integer multiple of the angular spacing between the ducts). This avoids pressure fluctuations and also avoids vibration and noise resulting from pressure fluctuations.

[0082] In some embodiments, the PX may include a rotor 360 configured to receive a first fluid, receive a second fluid, and exchange pressure between the first and second fluids. In some embodiments, the rotor 360 may form multiple ducts (e.g., ducts 310A-C in FIGS. 3A and 3B).

[0083] In some embodiments, the PX may further include a first end cover 330 in fluid communication with the rotor 360. The first end cover 330 may define a first kidney 320 (e.g., fluid may travel between the duct 310 of the rotor 360 and the kidney 320 of the first end cover 330). In some embodiments, the kidney angle range 340 of the first kidney 320 may be substantially an integer multiple of a duct angle spacing 350A between at least two adjacent ducts (e.g., ducts 310B and 310C) of the plurality of ducts. In some embodiments, the kidney angle range 340 is the angular distance between the open edge 301 and the closed edge 302 of the first kidney 320, and the duct angle spacing 350A is the angular distance between corresponding centers of the at least two adjacent ducts (e.g., ducts 310B and 310C). In some embodiments, the kidney angle range of the kidney is substantially an integer multiple of the duct angle spacing between at least two adjacent ducts of the plurality of ducts (e.g., ducts 310B and 310C), and the angle range may include an angle range within + / - 10 percent of the integer multiple. For example, kidney angle range 340 would allow for a duct angle spacing between at least two adjacent ducts such that the duct area exposed to the kidney does not change by more than 10% over time.

[0084] In some embodiments, the kidney opening edge is the edge of the kidney where the duct begins to overlap the kidney as the rotor rotates. In some embodiments, the kidney closing edge is the edge of the kidney where the duct begins to reduce overlap and cease to overlap the kidney as the rotor rotates. For example, in Figure 3B, duct 310A is depicted as beginning to overlap kidney 320 at kidney 320 opening edge 301. In another example, in Figure 3B, duct 310C is depicted as beginning to reduce overlap with kidney 320 at kidney 320 closing edge 302.

[0085] In some embodiments, kidneys with an angular extent that is substantially an integer multiple of the duct angular spacing (e.g., the angular distance between two adjacent ducts) ensure that the duct area (e.g., of the rotor duct) open to the kidneys remains substantially constant as the rotor rotates, leading to reduced flow fluctuations and pressure pulsations. In some embodiments, reducing flow fluctuations and pressure pulsations in the PX is beneficial for enhancing performance and efficiency. Flow fluctuations characterized by flow fluctuations and pressure pulsations accompanied by periodic pressure fluctuations can lead to operational inefficiencies, equipment wear, and potential downstream problems. By minimizing these undesirable fluctuations, the PX can operate more reliably, more efficiently, and with less mechanical stress, resulting in longer equipment life, energy savings, and improved system performance.

[0086] 3A and 3B, the duct area open to kidney 320 remains substantially constant even though the ducts (e.g., ducts 310A-C) may continuously rotate past kidney 320. In conventional systems, the kidney angle range is not a substantially integer multiple of the duct angle spacing, and the duct area open to the kidney region does not remain substantially constant over time, resulting in high flow rate fluctuations and pressure pulsations. High flow rate fluctuations and pressure pulsations are harmful because they reduce system efficiency, increase equipment wear, and disrupt fluid system stability, potentially leading to operational problems and potential damage.

[0087] In some embodiments, the kidney angle range may be 40 degrees and the duct angle spacing may be about 10 degrees.

[0088] In some embodiments, the kidney angle range of the kidney is substantially an integer multiple of the duct angle spacing between at least two adjacent ducts of the plurality of ducts (e.g., ducts 310B and 310C), and this angle range may include an angle range within + / - 10 percent of the integer multiple.

[0089] In some embodiments, the kidney and duct may be substantially similar in shape (e.g., trapezoidal). In some embodiments, using a kidney shape that matches the duct shape maximizes the radial seal and reduces leakage. Using a kidney-shaped body with the same radial extent as the duct can enhance the radial seal and minimize leakage. The radial seal helps the fluid or gas remain contained. Kidney-shaped seals with a curved, conformal design can create a reliable seal. When these seals are matched to the shape of the corresponding duct or channel in the system, they can enhance the sealing process by closely conforming to the contours of the duct. Such a seal maximizes the contact area between the seal and the duct wall, reducing the likelihood of leakage and improving the overall integrity, reliability, and performance of the system. In some embodiments, the PX of the present disclosure has a kidney that matches the duct to maximize the radial seal area.

[0090] In some embodiments, the rotors of the present disclosure have trapezoidal rather than circular ducts, maximizing the duct area density within the annular kidney, thereby reducing the maximum velocity within the duct and thus reducing inertial losses.

[0091] 3C-D are associated with a PX according to some embodiments. A PX of the present disclosure may include one or more features of FIGS.

[0092] 3C illustrates an end cover according to some embodiments. In some embodiments, one or more end covers of a PX include a sealing area (e.g., a spacing between spot features on the end cover) that is approximately the rotor duct width plus the rotor duct wall width, as shown in FIG.

[0093] In some embodiments, the end cover 330 includes a sealing area 375 (e.g., the spacing between kidneys on the end cover, the spacing between spot features on the end cover, etc.) that is approximately the rotor duct width 385 plus the rotor duct wall width 395, as shown in Figure 3C. In some embodiments, the rotor duct wall may be a partition between two adjacent ducts formed by the rotor.

[0094] 3D illustrates a seal plate, according to some embodiments. In some embodiments, the PX includes a passageway from the LPIN aperture 384 to the LPIN center bore 382. In some embodiments, the LPIN aperture 384 may be an LPIN kidney. In some embodiments, the PX of the present disclosure has LPIN rather than LPOUT as the center bore fluid, which reduces liquid refrigerant loss and reduces leakage overall.

[0095] In some embodiments, one or more end covers of the PX include one or more pre-ramps. In some embodiments, one or more end covers of the PX include an early opening (e.g., about 5 degrees). For example, the ramp may begin 5 degrees early at LPOUT.

[0096] In some embodiments, the disclosed PX (e.g., PX) may perform the dual functions of an expander and a compressor. In some embodiments, the disclosed PX has an increased duct size that allows for a lower RPM for the same flow rate, thereby reducing the number of pressure cycles in a given time and reducing noise and vibration. In some embodiments, the disclosed PX has two slopes on each kidney, which allows for smooth fluid inflow and outflow from the rotor and reduces shock losses. In some embodiments, the disclosed PX has increased bearing stiffness through the use of shallow circumferential grooves and increased radial bearing clearance. In some embodiments, the disclosed PX has reduced axial clearance to minimize leakage.

[0097] In some embodiments, the PX of the present disclosure increases the size of the kidney, allowing multiple ducts to open to the kidney simultaneously, reducing pressure and flow pulsations at the ports and thereby reducing vibrations.

[0098] In some embodiments, the PX of the present disclosure has the addition of spot faces at the HPOUT and LPOUT ports, which slows down the rate at which the ducts pressurize and depressurize, thereby reducing mixing and noise.

[0099] In some embodiments, the present disclosure includes PX-based energy recovery devices and derivative applications in transcritical CO2 refrigeration systems or heat pumps. In some embodiments, the PX of the present disclosure reduces energy consumption in transcritical CO2 refrigeration cycles, heat pump cycles, and derivatives thereof.

[0100] FIG. 4 shows end covers 430 and 432, according to some embodiments.

[0101] In some embodiments, first end cover 430 of FIG. 4 is an end cover that is the same as or similar to end cover 430 of FIGS. 3A-3B.

[0102] In some embodiments, the PX may include a rotor configured to receive a first fluid, receive a second fluid, and exchange pressure between the first and second fluids. In some embodiments, the rotor may form multiple ducts (e.g., ducts 310A-C in FIGS. 3A and 3B).

[0103] In some embodiments, the PX further comprises a first end cover 430 in fluid communication with the rotor, the first end cover 430 forming the first kidney 420 as may be said.

[0104] In some embodiments, the PX may include a second end cover 432 in fluid communication with the rotor. In some embodiments, the first end cover 430 may be in fluid communication with a first distal end of the rotor, and the second end cover 432 may be in fluid communication with a second distal end of the rotor. In some embodiments, the first end cover 430 and the second end cover 432 substantially align to allow precise positioning of the kidneys (e.g., the first kidney 420 and the second kidney 422) relative to one another. For example, the first end cover 430 and the second end cover 432 can be aligned so that the first kidney 420 and the second kidney 422 are offset (e.g., there is a delay angle between the first and second kidneys, the low pressure duct opens to the HPOUT kidney on the first end cover before opening to the HPIN kidney on the second end cover, the high pressure duct opens to the LPOUT kidney on the first end cover before opening to the LPIN kidney on the second end cover, etc.).

[0105] In some embodiments, the second end cover 432 forms a second kidney 422. In some embodiments, a delay angle 470 between the first kidney 420 of the first end cover 430 and the second kidney 422 of the second end cover 432 is in the range of 15 to 20 degrees. In some embodiments, the delay angle 470 is the angular distance between the closing edge 403 of the second kidney 422 of the second end cover 432 and the closing edge 401 of the first kidney 420 of the first end cover 430. In some embodiments, the first kidney 420 includes a closing edge 402, and the second kidney 422 includes a closing edge 404. In some embodiments, the delay angle 470 may be described as the angular distance between the opening edge 404 of the second kidney 422 of the second end cover 432 and the opening edge 402 of the first kidney 420 of the first end cover 430.

[0106] In some embodiments, the first end cover 430 and the second end cover 432 are substantially aligned to allow precise positioning of the kidneys (e.g., the third kidney 424 and the fourth kidney 426) relative to one another. For example, the first end cover 430 and the second end cover 432 can be aligned such that the third kidney 424 and the fourth kidney 426 are offset (e.g., there is a delay angle between the third and fourth kidneys, the low-pressure duct opens to the HPOUT kidney on the first end cover before opening to the HPIN kidney on the second end cover, the high-pressure duct opens to the LPOUT kidney on the first end cover before opening to the LPIN kidney on the second end cover, etc.).

[0107] In some embodiments, the second end cover 432 forms a third kidney 424. In some embodiments, a delay angle 460 between the third kidney 424 of the second end cover 432 and the fourth kidney 426 of the first end cover 430 is in the range of 15 to 20 degrees. In some embodiments, the delay angle 460 is the angular distance between the open edge 413 of the fourth kidney 426 of the first end cover 430 and the open edge 411 of the third kidney 424 of the second end cover 432. In some embodiments, the third kidney 424 includes a closed edge 412, and the fourth kidney 426 includes a closed edge 414. In some embodiments, the delay angle 460 may also be described as the angular distance between the closing edge 414 of the fourth kidney 426 of the first end cover 430 and the closing edge 412 of the third kidney 424 of the second end cover 432.

[0108] In some embodiments, the PX of the present disclosure has a delayed opening of the HPIN kidney relative to the HPOUT kidney. The PX may reduce or eliminate (e.g., completely eliminate) the HPIN fluid exiting through the HPOUT. Some conventional systems have a rotating duct (carrying low-pressure (LP) fluid) that simultaneously opens to both the HPIN and HPOUT kidneys, resulting in the duct being pressurized by fluid from both the HPIN and HPOUT kidneys, causing significant mixing and enthalpy reduction at the HPOUT. The PX of the present disclosure can reduce this mixing by opening the LP duct (e.g., a duct containing LP fluid) to the HPOUT before opening to the HPIN. A delay angle (e.g., an optimal delay angle) allows the duct to be pressurized (e.g., purely pressurized) by the HPOUT. When the duct opens to the HPIN, the pressure difference (across the duct) is small, resulting in reduced mixing (e.g., no pressure-driven jet) and forcing the duct contents to the HPOUT in a manner close to plug flow. In some embodiments, quasi-plug flow behavior may refer to uniform and continuous flow with minimal mixing or turbulence.

[0109] Quasi-plug flow behavior can describe the behavior of a fluid as it moves through a conduit or system (e.g., a PX). This flow pattern is characterized by minimal lateral mixing, ensuring that fluid elements move closely together without significant dispersion. The velocity profile remains relatively uniform across the cross section of the conduit, with fluid elements proceeding in an orderly manner and with little turbulence. This controlled, organized flow is particularly useful in applications where maintaining the identity of fluid elements and minimizing mixing are important to process efficiency and predictability.

[0110] Enthalpy may refer to a fundamental thermodynamic concept that describes the total energy content of a system. Enthalpy, denoted as H, includes both the system's internal energy (U) and the product of its pressure (P) and volume (V), and is represented by the equation H=U+PV. Enthalpy can describe how mixing of substances within a system (e.g., a PX) affects the system's overall energy content and pressure. The mixing process can result in changes in the ability to absorb or release heat, affecting the system's behavior. In some embodiments, two fluids of different enthalpies, when mixed, produce an intermediate enthalpy. This mixing can be driven by pressure dynamics within the PX.

[0111] In some embodiments, the PX of the present disclosure has a delayed opening of the LPIN kidney relative to the LPOUT kidney. In some embodiments, the PX has reduced mixing. For example, a relatively small amount of high-pressure (HP) duct fluid may end up in the LPIN. Some conventional solutions have a rotating duct that simultaneously opens HP fluid to both the LPIN and LPOUT kidneys, resulting in the duct fluid expanding into both the LPIN and LPOUT kidneys at the same time (pressure-driven jet). To prevent this from occurring, the rotor duct containing the HP fluid of the present disclosure is first allowed to open (e.g., align) with the LPOUT kidney (e.g., with a delay angle, optimal delay angle) so that the duct contents expand into the LPOUT and duct pressure equalizes. Subsequently, when the duct opens to the LPIN, mixing is reduced (e.g., pressure-driven expansion into the LPIN is avoided), and the contents are forced to the LPOUT in a plug-flow manner.

[0112] In some embodiments, the PX of the present disclosure has an HPIN delay aperture that transfers pressure and flow pulsation events to the HPOUT instead of the HPIN. Because the fluid is purely gaseous or mostly gaseous at the HPOUT, the fluid at the HPOUT is less dense and can handle pulsations better (e.g., a given flow pulsation is converted into a smaller pressure pulsation) as opposed to the fluid at the HPIN.

[0113] FIG. 5 illustrates an end cover, according to some embodiments.

[0114] In some embodiments, the end cover 500 (e.g., in fluid communication with the rotor) forms a first kidney 510. In some embodiments, the end cover 500 forms a second kidney 520. In some embodiments, fluid flow between the PX port (not shown in FIG. 5 ) and the rotor can pass through the first kidney 510 and the second kidney 520. In some embodiments, the ratio of the size of the first kidney 510 to the size of the second kidney 520 ranges from 3:2 to 5:2. In some embodiments, the kidney size can be a kidney surface area (e.g., the ratio of the surface area 512 of the first kidney 510 to the surface area 522 of the second kidney 520 ranges from 3:2 to 5:2).

[0115] In some embodiments, the PX of the present disclosure has unequal HP and LP kidney sizes. Because the density of the HP fluid is many times higher than that of the LP fluid, the inertial pressure loss (caused by the duct fluid continuously accelerating and decelerating) is higher on the HP side than on the LP side. This results in unbalanced rotor thrust. By sizing the HP and LP kidneys differently, the inertial DP losses in both the HP and LP kidneys can be better balanced, resulting in reduced rotor thrust loads.

[0116] In some embodiments, the first end cover 500 includes an end cover surface 502 (e.g., facing the rotor). In some embodiments, the end cover surface 502 forms a buffer chamber 560 located within a delay region 580 of the end cover 500. The buffer chamber may be a recess formed on the surface of the end cover. In some embodiments, this buffer may face the rotor or other moving components within the PX. The primary function of the buffer chamber may be to act as a space or cavity designed to stabilize fluid flow and minimize pressure fluctuations, especially in applications where controlled flow is essential (e.g., the PX). The buffer chamber may also equalize pressure differentials, reduce turbulence, and aid in heat dissipation. In some embodiments, the buffer chamber may separate and capture particulate matter or contaminants, ensuring a cleaner downstream fluid or gas.

[0117] In some embodiments, the delay region 580 is the region between the open edge 530 of the first kidney 510 of the first end cover and the open edge 530 of the first kidney 510 of the second end cover. In some embodiments, the kidney open edge is the edge of the kidney where the duct begins to overlap with the kidney as the rotor rotates. In some embodiments, the kidney closed edge is the edge of the kidney where the duct begins to reduce overlap and ceases to overlap with the kidney as the rotor rotates. For example, arrow 590 indicates the direction of rotor rotation. In some embodiments, the duct passes over the first kidney 510, the second kidney 520, and the buffer chamber 560 in the direction indicated by arrow 590.

[0118] In some embodiments, the spacing between the buffer chamber and the kidney is the same width as at least one duct (e.g., duct 550), which can prevent HPIN fluid (or, in alternative embodiments, other fluids) from entering the buffer chamber.

[0119] In some embodiments, the buffer chamber 560 has a shape substantially similar to the first kidney 510 (e.g., trapezoidal) and has an angular extent 562 substantially equal to the angular extent of the rotor duct of the rotor. In some embodiments, the buffer chamber 560 has a shape substantially similar to the first kidney 510 (e.g., trapezoidal) and may have an angular extent 562 that is substantially twice the angular extent 592 of the rotor duct of the rotor. In some embodiments, the buffer chamber 560 may be a blind recess. In some embodiments, the buffer chamber 560 may minimize pressure fluctuations in the PX.

[0120] In some embodiments, the first kidney 510 may be an HPIN kidney and the second kidney 520 may be an LPOUT kidney. In some embodiments, the first kidney 510 may be an HPOUT kidney and the second kidney 520 may be an LPIN kidney. Conventional solutions (e.g., using high-pressure and low-pressure kidneys of the same size) cause pressure losses. Because the density of the high-pressure fluid is many times higher than the density of the low-pressure fluid, the high-pressure fluid has a higher inertia (e.g., caused by the duct fluid being continuously accelerated and decelerated). This results in unbalanced rotor thrust in conventional solutions. In some embodiments, using unequal kidney sizes between the high-pressure and low-pressure kidneys (e.g., by sizing the high-pressure kidney to be larger than the low-pressure kidney) better balances the inertial differential pressure losses between both the high-pressure and low-pressure kidneys, resulting in reduced rotor thrust loads.

[0121] In some embodiments, fluid flow between the PX port and the rotor passes through a first kidney 510 and a second kidney 520. In some embodiments, the ratio of the size of the first kidney 510 to the size of the second kidney 520 ranges from about 3:2 to about 5:2.

[0122] FIG. 6 shows an end cover 600 including a buffer chamber 670, according to some embodiments.

[0123] In some embodiments, the PX includes a rotor configured to receive a first fluid, receive a second fluid, and exchange pressure between the first and second fluids. In some embodiments, the rotor forms a plurality of ducts. In some embodiments, the PX further includes a first end cover 600 in fluid communication with the rotor, the first end cover 600 forming a first kidney 620.

[0124] In some embodiments, the first end cover 600 forms the second kidney 622, and the first end cover 600 includes a first end cover surface 602 that faces the rotor, the first end cover surface 602 forming a buffer chamber 670 disposed within a delay region 680 of the first end cover 600. In some embodiments, the delay region 680 is the region between the closed edge 660 of the buffer chamber 670 and the open edge 630 of the first kidney 620. In some embodiments, the delay region 680 is the region between the open edge 630 of the first kidney 620 on the first end cover 600 and the open edge of the second kidney on the second end cover. The open edge 630 of the first kidney 620 on the first end cover 600 is represented by the dotted line 660 in FIG. 6 .

[0125] In some embodiments, the kidney opening edge is the edge of the kidney where the duct begins to overlap the kidney as the rotor rotates. In some embodiments, the kidney closing edge is the edge of the kidney where the duct begins to overlap less and ceases to overlap the kidney as the rotor rotates. For example, arrow 690 indicates the direction of rotor rotation. In some embodiments, the duct passes over first kidney 620, second kidney 622, and buffer chamber 670 in the direction indicated by arrow 690.

[0126] In some embodiments, the open edge of the buffer chamber is the edge of the buffer chamber where the duct begins to overlap with the buffer chamber as the rotor rotates, hi some embodiments, the closed edge of the buffer chamber is the edge of the buffer chamber where the duct begins to overlap less and ceases to overlap with the buffer chamber as the rotor rotates.

[0127] In some embodiments, the buffer chamber 670 is substantially similar in shape to the first kidney 620 (e.g., trapezoidal) and has an angular extent 682 substantially equal to the angular extent of the rotor duct of the rotor. In some embodiments, fluid flow between the PX port and the rotor passes through the first kidney 620 and the second kidney 622. In some embodiments, the ratio of the size of the first kidney 620 to the size of the second kidney 622 ranges from about 3:2 to about 5:2.

[0128] In some embodiments, the spacing between the buffer chamber and the kidney is the same width as at least one duct (e.g., duct 650), which can prevent HPIN fluid (or, in alternative embodiments, other fluids) from entering the buffer chamber.

[0129] In some embodiments, line 660 indicates where the HPOUT kidney opens on the second end cover. For a more detailed description, see Figures 7A-B and 8A-B.

[0130] FIG. 7A illustrates a PX with an end cover forming a rotor and a buffer chamber, according to some embodiments.

[0131] In some embodiments, the PX includes a rotor 730A configured to receive a first fluid, receive a second fluid, and exchange pressure between the first and second fluids. In some embodiments, the rotor 730A forms multiple ducts (e.g., an LP duct 760A). In some embodiments, an HP duct refers to a duct that contains an HP fluid. In some embodiments, the PX includes a first end cover 710A in fluid communication with the rotor 730A, the first end cover 710A forming a first kidney 750A. In some embodiments, the second end cover 712A forms a second kidney, an HPOUT kidney 740A. In some embodiments, the first end cover 710A includes a first end cover surface 770A facing the rotor 730A, which forms a buffer chamber 720A located in a delay region of the first end cover 710A (e.g., upstream of the HPIN kidney 750A). In some embodiments, the delay region may be the region between the open edge of the second kidney 740A (indicated by the dotted line 761A) and the open edge of the first kidney 750A on the second end cover.

[0132] In some embodiments, the PX700A may include a buffer chamber 720A on the HPIN end cover 710A upstream of the HPIN kidney 750A in the delay region (e.g., between the open edge of the HPIN kidney 750A and the open edge of the HPOUT kidney 740A). In some embodiments, the buffer chamber 720A may be a blind recess having a shape and radial extent similar to that of the rotor duct. In some embodiments, the buffer chamber 720A may be machined into the HPIN end cover 710A in the delay region. In some embodiments, the start angle of the blind recess (e.g., the buffer chamber 720A) matches the start angle of the HPOUT kidney 740A (e.g., the buffer chamber 720A and the HPOUT kidney are substantially aligned). Line 761A indicates the match start angle between the buffer chamber 720A and the HPOUT kidney 740A. In some embodiments, the termination angle of the blind recess (e.g., buffer chamber 720A) can be set to prevent any communication with the HP IN kidney 750A through the duct. In some embodiments, the blind recess can continuously hold a "buffer" of HP IN fluid.

[0133] In some embodiments, the PX700A includes a second end cover 712A in fluid communication with the rotor 730A. In some embodiments, the second end cover 712A forms a third kidney 740A. In some embodiments, when a first duct of the plurality of ducts (e.g., partially pressurized duct 764A) is substantially aligned with the buffer chamber 720A, the third kidney 740A is substantially aligned with the first duct (e.g., as shown by line 761A).

[0134] In some embodiments, the third kidney 740A may be a HPOUT kidney, and the first and second ducts may be low-pressure ducts (e.g., ducts filled with low-pressure fluid). In some embodiments, the first kidney 750A may be a HPIN kidney, and the first duct (e.g., the partially pressurized duct 764A) is substantially aligned with the first kidney 750A after aligning with the buffer chamber 720A. For example, the partially pressurized duct 764A is aligned with the first kidney 750A only after rotating and passing through the buffer chamber 720A.

[0135] In some embodiments, the kidney angle range of the first kidney 750A can be substantially an integer multiple of the duct angle range between at least two adjacent ducts of the plurality of ducts (e.g., LP duct 760A and partially pressurized duct 764A). In some embodiments, the LP duct refers to a duct that contains the LP fluid. In some embodiments, the kidney angle range is the angular distance between the open edge and the closed edge of the first kidney 750A, and the duct angle range is the angular distance between the corresponding centers of the at least two adjacent ducts.

[0136] In some embodiments, when a duct carrying low-pressure fluid (e.g., LP duct 760A) opens to the HPOUT kidney 740A, the duct can simultaneously open to the buffer chamber 720A, causing the LP duct 760A to be pressurized simultaneously from its first and second distal ends. In some embodiments, when the duct is simultaneously pressurized at its first distal end (e.g., by the HPOUT kidney 740A) and its second distal end (e.g., by the buffer chamber 720A), the duct can be pressurized faster, and the amplitude of the pressure waves in the duct can be damped, resulting in reduced jetting (e.g., when opening to the HPIN kidney 750A) and reduced mixing.

[0137] In some embodiments, the buffer chamber 720A is substantially similar in shape to the first kidney 750A (e.g., trapezoidal) and has an angular extent substantially equal to the angular extent of the rotor duct (e.g., partially pressurized rotor duct 764A). In some embodiments, fluid flow between the ports of the PX700A and the rotor 730A is through a third kidney formed by the first kidney 750A and the end cover 710A. In some embodiments, the ratio of the size of the first kidney 750A to the size of the second kidney is in the range of 3:2 to 5:2.

[0138] In some embodiments, the spacing between the buffer chamber and the kidney is as wide as at least one duct, which can prevent the HPIN fluid (or, in alternative embodiments, other fluids) from entering the buffer chamber.

[0139] FIG. 7B illustrates a PX with an end cover forming a rotor and a buffer chamber, according to some embodiments.

[0140] In some embodiments, the PX700B includes a rotor 730B configured to receive a first fluid, receive a second fluid, and exchange pressure between the first and second fluids. In some embodiments, the rotor 730B includes a plurality of ducts (e.g., LP duct 760B). In some embodiments, the PX700B includes a first end cover 710B in fluid communication with the rotor 730B. In some embodiments, the first end cover 710B includes a first end cover surface 770B facing the rotor 730B. In some embodiments, the first end cover surface 770B forms a buffer chamber 720B located in a delay region of the first end cover 710B (see FIGS. 5 and 6). In some embodiments, the first end cover 710B forms a first kidney 750B. In some embodiments, the second end cover 712B forms a second kidney 740B. In some embodiments, the delay region is the region between the open edge of the first kidney 750B on the end cover 710B and the open edge of the first kidney 740B on the second end cover 712B.

[0141] In some embodiments, PX700B includes a second end cover 712B in fluid communication with rotor 730B. In some embodiments, second end cover 712B forms third kidney 740B. In some embodiments, a first duct and a second duct (e.g., partially pressurized duct 764B) of the plurality of ducts are simultaneously substantially aligned with buffer chamber 720B (e.g., as shown by lines 761B and 762B), while third kidney 740B is substantially aligned with the first duct (e.g., as shown by line 761B).

[0142] In some embodiments, the third kidney 740B may be a HPOUT kidney, and the first and second ducts may be low-pressure ducts (e.g., ducts filled with low-pressure fluid). In some embodiments, the first kidney 750B may be a HPIN kidney, and the first duct substantially aligns with the first kidney 750B after aligning with the buffer chamber 720B. For example, the partially pressurized duct 764B aligns with the first kidney 750B only after rotating past the buffer chamber 720B.

[0143] In some embodiments, the kidney angle range of the first kidney 750B can be substantially an integer multiple of the duct angle range between at least two adjacent ducts of the plurality of ducts (e.g., partially pressurized duct 764B). In some embodiments, the kidney angle range is the angular distance between the open edge and the closed edge of the first kidney 750B, and the duct angle range is the angular distance between the corresponding centers of the at least two adjacent ducts.

[0144] In some embodiments, the buffer chamber 720B is substantially similar in shape to the first kidney 750B (e.g., trapezoidal) and has an angular extent substantially twice that of the rotor duct 764B. In some embodiments, fluid flow between the ports of the PX700B and the rotor 730B passes through a third kidney formed by the first kidney 750B and the end cover 710B. In some embodiments, the ratio of the size of the first kidney 750B to the size of the second kidney is in the range of 3:2 to 5:2.

[0145] In some embodiments, the spacing between the buffer chamber and the kidney is as wide as at least one duct, which can prevent the HPIN fluid (or, in alternative embodiments, other fluids) from entering the buffer chamber.

[0146] FIG. 8A illustrates a PX with an end cover forming a rotor and a buffer chamber, according to some embodiments.

[0147] In some embodiments, a buffer chamber can be implemented upstream of the LPIN kidney in the delay region (see Figures 5 and 6), which effectively increases the delay angle and allows the high pressure duct to begin depressurizing before opening to the LPIN kidney.

[0148] In some embodiments, the PX800A includes a rotor 830A configured to receive a first fluid, receive a second fluid, and exchange pressure between the first and second fluids. In some embodiments, the rotor 830A forms multiple ducts (e.g., HP duct 860A, partially depressurized duct 864A, etc.). In some embodiments, an HP duct refers to a duct that contains an HP fluid. In some embodiments, the PX800A includes a first end cover 810A in fluid communication with the rotor 830A. In some embodiments, the first end cover 810A forms a first kidney 850A. In some embodiments, the first kidney 850A can be an LPIN kidney. In some embodiments, the first end cover 810A forms a second kidney (not shown in FIG. 8A ). In some embodiments, the first end cover 810A includes a first end cover surface 870A that faces the rotor 830A. In some embodiments, the first end cover surface 870A forms a buffer chamber 820A located in a delay region of the first end cover 810A (e.g., upstream of the HPIN kidney 850A). In some embodiments, the delay region may be the region between the open edge of the first kidney 850A and the open edge of the first kidney 840A (e.g., line 861A). In some embodiments, upstream refers to the direction opposite to the direction of rotor rotation.

[0149] In some embodiments, the PX800A may include a buffer chamber 820A on the LPIN end cover 810A upstream of the LPIN kidney 850A, within the delay region (e.g., between the open edge of the LPIN kidney 850A and the open edge of the LPOUT kidney 840A). In some embodiments, the buffer chamber 820A may be a blind recess having a similar shape and radial extent to the kidney. In some embodiments, the buffer chamber 820A may be machined into the LPIN end cover 810A within the delay region. In some embodiments, the start angle of the blind recess (e.g., the buffer chamber 820A) matches the start angle of the LPOUT kidney 840A (e.g., the buffer chamber 820A and the LPOUT kidney are substantially aligned). Line 861A indicates the alignment start angle between the buffer chamber 820A and the LPOUT kidney 840A. In some embodiments, the termination angle of the blind recess (e.g., buffer chamber 820A) can be set to prevent any communication with the LPIN kidney 850A through the duct. In some embodiments, the blind recess can continuously hold a "buffer" of LPOUT fluid.

[0150] In some embodiments, PX800A includes a second end cover 812A in fluid communication with rotor 830A. In some embodiments, second end cover 812A forms third kidney 840A. In some embodiments, when a first duct of the plurality of ducts (e.g., partially depressurized duct 864A) is substantially aligned with buffer chamber 820A, third kidney 840A is substantially aligned with the first duct (e.g., as shown by line 861A).

[0151] In some embodiments, the third kidney 840A may be an LPOUT kidney, and the first and second ducts may be high-pressure ducts (e.g., ducts filled with high-pressure fluid). In some embodiments, the first kidney 850A may be an LPIN kidney, and the first duct is substantially aligned with the first kidney 850A after aligning with the buffer chamber 820A. For example, the partially pressurized duct 864A is aligned with the first kidney 850A only after rotating and passing through the buffer chamber 820A.

[0152] In some embodiments, the kidney angle range of the first kidney 850A may be substantially an integer multiple of the duct angle range between at least two adjacent ducts of the plurality of ducts (e.g., LP duct 860A and partially pressurized duct 864A). In some embodiments, the kidney angle range is the angular distance between the open edge and the closed edge of the first kidney 850A, and the duct angle range is the angular distance between the corresponding centers of the at least two adjacent ducts.

[0153] In some embodiments, when a duct carrying high-pressure fluid (e.g., HP duct 860A) opens to the LPOUT kidney 840A, the duct can simultaneously open to the buffer chamber 820A, thereby simultaneously depressurizing the HP duct 860A from its first and second distal ends. In some embodiments, when the duct is simultaneously depressurized at its first distal end (e.g., by the LPOUT kidney 840A) and its second distal end (e.g., by the buffer chamber 820A), the duct can be depressurized faster, and the amplitude of pressure waves in the duct can be attenuated, jetting (e.g., when opening to the LPIN kidney 850A) can be reduced, and mixing can be reduced.

[0154] In some embodiments, the buffer chamber 820A is substantially similar in shape to the first kidney 850A (e.g., trapezoidal) and has an angular extent substantially equal to the angular extent of the rotor duct 860A. In some embodiments, fluid flow between the ports of the PX 800A and the rotor 830A passes through a third kidney formed by the first kidney 850A and the end cover 810A. In some embodiments, the ratio of the size of the first kidney 850A to the size of the second kidney is in the range of 3:2 to 5:2.

[0155] In some embodiments, the spacing between the buffer chamber and the kidney is as wide as at least one duct, which can prevent LPIN fluid (or, in alternative embodiments, other fluids) from entering the buffer chamber.

[0156] FIG. 8B illustrates a PX with an end cover forming a rotor and a buffer chamber, according to some embodiments.

[0157] In some embodiments, the PX800B includes a rotor 830B configured to receive a first fluid, receive a second fluid, and exchange pressure between the first and second fluids. In some embodiments, the rotor 830B includes a plurality of ducts (e.g., HP duct 860B, partially depressurized duct 864B, etc.). In some embodiments, the PX800B includes a first end cover 810B in fluid communication with the rotor 830B. In some embodiments, the first end cover 810B includes a first end cover surface 870B facing the rotor 830B. In some embodiments, the first end cover surface 870B forms a buffer chamber 820B located in a delay region of the first end cover 810B (see FIGS. 5 and 6). In some embodiments, the first end cover 810B forms a first kidney 850B and a second kidney (not shown in FIG. 8B). In some embodiments, the delay region is the region between the open edge of first kidney 840B and the open edge of first kidney 850B.

[0158] In some embodiments, PX800B includes a second end cover 812B in fluid communication with rotor 830B. In some embodiments, second end cover 812B forms third kidney 840B. In some embodiments, a first duct and a second duct (e.g., partially pressurized duct 864B) of the plurality of ducts are simultaneously substantially aligned with buffer chamber 820B (e.g., as shown by lines 861B and 862B), while third kidney 840B is substantially aligned with the first duct (e.g., as shown by line 861B).

[0159] In some embodiments, the third kidney 840B may be an LPOUT kidney, and the first and second ducts may be high-pressure ducts (e.g., ducts filled with high-pressure fluid). In some embodiments, the first kidney 850B may be an LPIN kidney, and the first duct is substantially aligned with the first kidney 850B after aligning with the buffer chamber 820B. For example, the partially pressurized duct 864B is aligned with the first kidney 850B only after rotating and passing through the buffer chamber 820B.

[0160] In some embodiments, the kidney angle range of the first kidney 850B can be substantially an integer multiple of the duct angle range between at least two adjacent ducts of the plurality of ducts (e.g., partially pressurized duct 864B). In some embodiments, the kidney angle range is the angular distance between the open edge and the closed edge of the first kidney 850B, and the duct angle range is the angular distance between the corresponding centers of the at least two adjacent ducts.

[0161] In some embodiments, the buffer chamber 820B is substantially similar in shape to the first kidney 850B (e.g., trapezoidal) and has an angular extent substantially twice that of the rotor duct 860B. In some embodiments, fluid flow between the ports of the PX 800B and the rotor 830B passes through a third kidney formed by the first kidney 850B and the end cover 810B. In some embodiments, the ratio of the size of the first kidney 850B to the size of the second kidney is in the range of 3:2 to 5:2.

[0162] In some embodiments, the spacing between the buffer chamber and the kidney is as wide as at least one duct, which can prevent LPIN fluid (or, in alternative embodiments, other fluids) from entering the buffer chamber.

[0163] FIG. 9 illustrates a rotor forming a duct, according to some embodiments.

[0164] In some embodiments, rotor 900 may be configured to receive a first fluid, receive a second fluid, and exchange pressure between the first and second fluids. In some embodiments, rotor 900 forms multiple ducts (e.g., inner duct 910, outer duct 920, etc.).

[0165] In some embodiments, rotor 900 forms ducts in multiple concentric rows (e.g., inner row 912, outer row 922, etc.). For example, inner duct 910 forms inner row 912, and outer duct 920 forms outer row 922. In some embodiments, inner row 912 and outer row 922 are concentric rows. In some embodiments, concentric rows may refer to a pattern in which multiple rows of objects (e.g., ducts) are arranged in a circular pattern, with each row spaced a distance from the center, creating a series of circles or rings. In some embodiments, rows may be staggered. For example, lines 930 and 932 show how ducts in inner ring 912 and ducts in outer ring 922 may be staggered. In some embodiments, using staggered rows can reduce the total amount of duct volume pressurized and / or depressurized at one time, reducing noise and vibration in the PX.

[0166] In some embodiments, the use of multiple rows of staggered ducts can reduce pressure pulsations at the HPOUT port and HPOUT kidney. For example, when a low-pressure duct (e.g., filled with LPIN fluid) opens to the HPOUT kidney, a pressure differential causes a jet of fluid to rush into the low-pressure duct, causing a short, nearly instantaneous flow reversal at the HPOUT port. This flow reversal causes a momentary pressure drop at the HPOUT port, resulting in pressure pulsations and oscillations. By increasing the number of ducts and reducing the size of each duct (while the total duct volume remains constant), the magnitude and duration of the flow reversal are kept small. This results in smaller pressure pulsations and corresponding oscillations at the HPOUT port.

[0167] In some embodiments, the duct size can be increased to allow for higher flow rates at lower RPMs, reducing the number of pressure cycles in a given time, thereby reducing noise and vibration. In some embodiments, as the kidney size increases, multiple ducts can open up to the kidney (e.g., overlap with the kidney), thereby simultaneously reducing pressure and flow pulsations at the ports, thereby reducing vibration. In some embodiments, trapezoidal ducts (rather than annular ducts) can be used to maximize duct area density within the annular kidney, thereby reducing maximum velocities within the ducts and thus inertial losses.

[0168] In some embodiments, using an odd number of ducts (e.g., rather than an even number) allows for the temporal separation of pressurization and depressurization events, thereby reducing noise and vibration.

[0169] FIG. 10 illustrates a pre-pressurization hole, according to some embodiments.

[0170] In some embodiments, pre-pressurizing the low-pressure duct before it opens to the HPOUT kidney 1010 can be achieved using a kidney pre-pressurization opening 1020, a pre-pressurization conduit 1030, and a pre-pressurization opening 1000 connecting the HPOUT kidney 1010 to the low-pressure duct upstream of the HPOUT kidney 1010. This allows pre-pressurization of the duct and allows for faster stabilization of the pressure when the duct finally opens to the HPOUT kidney 1010. In some embodiments, the conduit 1030 and the pre-pressurization opening 1000 are located in the end cover 1040. In some embodiments, the pre-pressurization opening 1000 faces the rotor (e.g., which is fluidly connected to the end cover 1040). An arrow 1070 indicates the direction of rotation of the rotor (e.g., which is fluidly connected to the end cover).

[0171] FIG. 11A illustrates a spot face, according to certain embodiments.

[0172] In some embodiments, the HP kidney may have a deeper spot face than a conventional spot face. For example, the PX may include a rotor 1110A that forms a duct. The PX may further include an end cover 1100A that includes an HP kidney 1120A. The HP kidney 1120A includes a deeper spot face 1190A than a conventional spot face. In some embodiments, the addition of a deeper spot face may be performed at the HPOUT or LPOUT port, thereby slowing the rate of pressurization and depressurization of the duct. This reduces mixing and noise. Compressible fluids, such as CO2, can choke when they leak from the HP kidney (e.g., the HP kidney 1120A) through a spot face into the LP duct. This effectively limits the rate of pressurization of the LP duct. An alternative spot face design (e.g., a deeper spot face) allows for faster pressurization, even when the pressure ratio exceeds the critical pressure ratio for choking.

[0173] A conventional PX may include an HP kidney with a shallow spot face. For example, a conventional PX may include a rotor that forms a duct. A conventional PX may further include an end cover that includes an HP kidney. The HP kidney may include a shallow spot face. A shallow spot face can slow the rate at which the duct is pressurized and depressurized, thereby reducing mixing and noise. A compressible fluid such as CO2 chokes when it leaks from the HP kidney (e.g., HP Kidney 1120A) through the spot face into the LP duct. This effectively limits the rate at which the LP duct is pressurized.

[0174] The foregoing description provides numerous specific details, including examples of specific systems, components, methods, etc., to provide a thorough understanding of some embodiments of the present disclosure. However, it will be apparent to one skilled in the art that at least some embodiments of the present disclosure may be practiced without such specific details. In other instances, well-known components or methods are not described in detail or are presented in simple block diagram form to avoid unnecessarily obscuring the present disclosure. As such, the specific details described are merely exemplary. Particular implementations may vary from such example details and still be considered within the scope of the present disclosure. The system descriptions herein may include descriptions of one or more optional components. Components may be included in combinations not specifically discussed in the present disclosure and still be within the scope of the present disclosure.

[0175] References throughout this specification to "one embodiment" or "an embodiment" mean that a particular feature, structure, or characteristic described in connection with that embodiment is included in at least one embodiment. Thus, the appearances of the phrase "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the term "or" is intended to mean an inclusive "or" rather than an exclusive "or." When the terms "about," "substantially," or "approximately" are used herein, this is intended to mean that the stated nominal value is accurate to within 10%. Additionally, the terms "first," "second," "third," "fourth," etc., as used herein are intended as labels to distinguish between different elements and do not necessarily have an ordinal meaning according to their numerical designations.

[0176] As used herein, the terms "across," "under," "between," "disposed on," "in front of," "after," and "on" refer to the relative location of a layer of material or component with respect to another layer or component. For example, a layer disposed on, over, or under another layer may be in direct contact with the other layer or there may be one or more intervening layers. Furthermore, a layer disposed between two layers may be in direct contact with the two layers or there may be one or more intervening layers. Similarly, unless explicitly stated otherwise, a feature disposed between two features may be in direct contact with the adjacent feature or there may be one or more intervening layers or components.

[0177] It is to be understood that the above description is intended to be illustrative, and not limiting. Many other embodiments will be apparent to those skilled in the art upon reading and understanding the above description. Thus, the scope of the present disclosure should be determined with reference to the appended claims, along with the full scope of equivalents to which each claim is entitled.

Claims

1. A pressure exchanger (PX), said PX comprising: a rotor configured to receive a first fluid, receive a second fluid, and exchange pressure between the first fluid and the second fluid, the rotor defining a plurality of ducts; a first end cover fluidly connected to the rotor, the first end cover forming a first kidney, the kidney angle range of the first kidney being substantially an integer multiple of a duct angle spacing between at least two adjacent ducts of the plurality of ducts, the kidney angle range being the angular distance between an open edge and a closed edge of the first kidney, and the duct angle spacing being the angular distance between corresponding centers of the at least two adjacent ducts, PX.

2. 2. The PX of claim 1, further comprising a second end cover in fluid communication with the rotor, the second end cover forming a second kidney, a delay angle between the first kidney of the first end cover and the second kidney of the second end cover being in the range of 15 to 20 degrees, and the delay angle being the angular distance between the closing edge of the second kidney and the closing edge of the first kidney.

3. The PX of claim 1 , wherein said rotor forms said ducts in a plurality of concentric rows, said rows being staggered.

4. 2. The PX of claim 1, wherein the PX comprises a second end cover, the second end cover forming a second kidney, the first end cover having a first end cover surface facing the rotor, the first end cover surface forming a buffer chamber disposed in a delay region of the first end cover, the delay region being the region between the open edge of the second kidney and the open edge of the first kidney.

5. 2. The PX of claim 1, wherein the first end cover forms a third kidney, fluid flow between the port of the PX and the rotor passes through the first kidney and the third kidney, and the ratio of the size of the first kidney to the size of the third kidney is in the range of 3:2 to 5:

2.

6. A pressure exchanger (PX), said PX comprising: a rotor configured to receive a first fluid, receive a second fluid, and exchange pressure between the first fluid and the second fluid, the rotor defining a plurality of ducts; a first end cover in fluid communication with the rotor, the first end cover having a first end cover surface facing the rotor, the first end cover surface forming a buffer chamber disposed in a delay region of the first end cover, the first end cover forming a first kidney; PX, comprising a second end cover forming a second kidney, wherein the delay region is the region between the open edge of the second kidney and the open edge of the first kidney.

7. 7. The PX of claim 6, further comprising a second end cover fluidly connected to the rotor, the second end cover forming a third kidney, the third kidney being substantially aligned with the first duct when a first duct of the plurality of ducts is substantially aligned with the buffer chamber.

8. The PX of claim 7, wherein the first duct and the second duct of the plurality of ducts are simultaneously substantially aligned with the buffer chamber, while the third kidney is substantially aligned with the first duct.

9. 9. The PX of claim 8, wherein the third kidney is a high pressure out (HPOUT) kidney, and the first duct and the second duct are low pressure ducts.

10. 10. The PX of claim 9, wherein the first kidney is a high pressure in (HPIN) kidney, and the first duct is substantially aligned with the first kidney after being aligned with the buffer chamber.

11. 9. The PX of claim 8, wherein the third kidney is a low pressure out (LPout) kidney, and the first duct and the second duct are high pressure ducts.

12. 12. The PX of claim 11, wherein the first kidney is a low pressure in (LPin) kidney, and the first duct is substantially aligned with the first kidney after being aligned with the buffer chamber.

13. 8. The PX of claim 7, wherein the kidney angle range of the first kidney is substantially an integer multiple of a duct angle spacing between at least two adjacent ducts of the plurality of ducts, the kidney angle range being the angular distance between an open edge and a closed edge of the first kidney, and the duct angle spacing being the angular distance between corresponding centers of the at least two adjacent ducts.

14. 8. The PX of claim 7, wherein the buffer chamber has a shape substantially similar to the first kidney and an angular extent substantially equal to or substantially twice the angular extent of a rotor duct of the plurality of ducts.

15. 7. The PX of claim 6, wherein the first end cover forms a third kidney, fluid flow between the port of the PX and the rotor passes through the first kidney and the third kidney, and the ratio of the size of the first kidney to the size of the second kidney is in the range of 3:2 to 5:

2.

16. A pressure exchanger (PX), said PX comprising: a rotor configured to receive a first fluid, receive a second fluid, and exchange pressure between the first fluid and the second fluid; a first end cover fluidly connected to the rotor, the first end cover forming a first kidney and a second kidney, fluid flow between a port of the PX and the rotor passing through the first kidney and the second kidney, and a ratio of the size of the first kidney to the size of the second kidney being in the range of 3:2 to 5:

2.

17. 17. The PX of claim 16, wherein the first kidney is a high-pressure kidney and the second kidney is a low-pressure kidney.

18. 18. The PX of claim 17, further comprising a second end cover in fluid communication with the rotor, the second end cover forming a third kidney and a fourth kidney, fluid flow between a port of the PX and the rotor passing through the third kidney and the fourth kidney, and a ratio of the size of the third kidney to the size of the fourth kidney being in the range of 3:2 to 5:

2.

19. 19. The PX of claim 18, wherein the third kidney is a high-pressure kidney and the fourth kidney is a low-pressure kidney.

20. 17. The PX of claim 16, wherein the rotor forms a plurality of ducts, and wherein a kidney angle range of the first kidney is substantially an integer multiple of a duct angle spacing between at least two adjacent ducts of the plurality of ducts, the kidney angle range being the angular distance between an open edge and a closed edge of the first kidney, and the duct angle spacing being the angular distance between corresponding centers of the at least two adjacent ducts.

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