Multi-role pump, system comprising the same, methods of making and method of using the same

Abstract

A multi-role pump and a system such as a refueling station comprising such a pump are provided. The multi-role pump is configured to transfer a liquefied fuel such as hydrogen from a delivery truck, fuel the liquefied fuel in liquid form to a first vehicle, and boost the liquefied fuel for a second vehicle with various higher pressure onboard storage systems, while minimizing liquid fuel boil-off loss. The system is configured to dispense a fuel such as hydrogen to vehicles in different modes, for example, in a form selected from liquid hydrogen, cryo-compressed hydrogen, and compressed hydrogen gases under different pressures such as 35 MPa and 70 MPa. A method of making the same and a method of using are also provided.

Description

MULTI-ROLE PUMP, SYSTEM COMPRISING THE SAME, METHODS OF MAKINGAND METHOD OF USING THE SAMEPRIORITY CLAIM AND CROSS-REFERENCE

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 655,389, filed June 3, 2024, which application is expressly incorporated by reference herein in its entirety.FIELD OF THE INVENTION

[0002] The disclosure relates to systems and methods for storing, dispensing, and using a liquefied gas generally. More particularly, the disclosed subject matter relates to a pump, a system comprising the pump, a method of making the pump or system, and a method for dispensing and using liquefied gas such as liquid hydrogen for uses such as transportation applications.BACKGROUND

[0003] Many motor vehicles are currently powered by internal combustion engines with fossil fuels. Due to limited supply and adverse environmental effects associated with burning petroleum-derived fuels, vehicles are now being developed that are powered by alternative environmentally friendly fuels like hydrogen. Fuel cells can be used to produce electric power for motor vehicles by electrochemically reacting hydrogen fuel with an oxidant such as air. Other hydrogen-powered vehicles can be powered by combustion of hydrogen. Fueling or refueling hydrogen to fuel cell vehicles (FCV) and other hydrogen- powered vehicles presents different challenges from adding petroleum-based fuels like gasoline into a vehicle.

[0004] Hydrogen refueling stations for hydrogen powered vehicles with fuel cells or internal combustion engines can store fuel as a gas or a liquid before it is dispensed to vehicles. Liquefied gases or fuels such as liquid hydrogen can be stored in a cryogenic tank, which is thermally insulated from the environment. However, heat leak into a tank causes liquefied gas to vaporize to generate “boil-off’ vapor as the liquid absorbs the heat leak from the environment. Pressure inside the tank increases as the vapor continues to build up in it. Excess vapor must be vented through a relief valve to the environment to keep the tank under the pressure limit, causing loss of some liquefied fuel or gas.

[0005] Vent loss during liquid hydrogen (LH2) transfer or offloading from a delivery tanker truck, also known as a liquid hauler, to a stationary cryotank can be substantial, up to 20% of the delivered product amount, with the state-of-the-art pressure transfer method. International Application No. PCT / US2023 / 027245 filed July 10, 2023 discloses a method for zero boil-off operation in liquefied gas applications. In such applications, a high flow pump, approximately 100 gallons per minute (gpm) of LH2, at discharge pressures up to 25 bar(g) (2.5 MPa) is required as a transfer pump to provide the motive force for liquid transfer. Such a flow rate is desirable because the transfer operation is ideally completed in less than two hours. For a typical stationary cryotank of 18,000 gallons with starting liquid level of 30% and final fill liquid level of 90%, a 100-gpm pump would finish transfer in the desired time window.

[0006] Industry is also exploring new methods of onboard storage for heavy duty vehicles. In addition to H70 and H35 compressed gas at a nominal pressure of 70 MPa and 35 MPa, respectively, efforts are underway to store liquid hydrogen onboard (liquid onboard) and cryo-compressed hydrogen (ccFh). For liquid onboard, the maximum onboard storage pressure is less than 25 bar(g) (2.5 MPa), but with ccFh, the maximum pressure is approximately 400 bar(g) (40 MPa), similar to the H35 storage system, except that the storage vessel also needs to be vacuum-insulated.

[0007] Other liquefied gas applications involving liquid helium, liquid natural gas, liquid oxygen, liquid nitrogen, and others generally known as industrial gases face similar challenges associated with vent loss, although the economic impact varies depending on the value of the product involved.

[0008] Liquid transfer operation and vehicle fueling with different onboard storage methods are time-shifted and do not always occur simultaneously. Thus, providing dedicated equipment for each role would complicate the refueling station design and increase station capital and maintenance cost.

[0009] It is desirable to have a method to maximize flexibility and capital efficiency for equipment by using one pump for multiple roles that are not simultaneously needed.SUMMARY OF THE INVENTION

[0010] The present disclosure provides a pump, a system such as a refueling station comprising the pump, a method of making the pump or the system, and a method of using the pump or the system for storing, dispensing, and using liquefied gas such as liquid hydrogen, for applications, for example, for transportation applications.

[0011] In accordance with some embodiments, a multi-role pump is provided. Such a pump comprises a plurality of single-piston elements arranged mechanically or controlled electronically to provide the desired flow, pressure, power demand and boil-off loss targets. This multi-role pump is used in a refueling station where, by activating appropriate control valves, it supports zero-loss liquid transfer operation from a liquid hydrogen delivery tanker truck, liquid onboard fueling, and as a booster pump in a two-stage high-pressure pumping operation to support ccH2, H35, and H70 fueling.

[0012] In accordance with some embodiments, a pump provided in the present disclosure comprises an inlet, an outlet, and a plurality of single-piston elements, which are configured to accept a liquefied fuel via the inlet and discharge the liquefied fuel via the outlet. The plurality of single-piston elements are arranged mechanically or controlled electronically to achieve a flow rate and a pressure. The flow rate is selected from at least two predetermined different flow rates. The pressure is selected from at least two predetermined different pressures. The flow rate has a peak-to-average ratio less than 1.6 for a smooth operation. The pumping efficiency is at least 70%. In some embodiments, the liquefied fuel comprises or is liquid hydrogen.

[0013] In some embodiments, the plurality of single-piston elements are arranged in parallel. The pump further comprises a crank shaft. The plurality of single-piston elements are mechanically connected with the crank shaft.

[0014] In some embodiments, the pump further comprises a gear. The plurality of single-piston elements are mechanically connected eccentrically.

[0015] In some embodiments, each of the plurality of single-piston elements is connected with a respective drive and synchronized via electronic controls.

[0016] In some embodiments, the inlet is configured to be fluidly connected to a cryotank, which is configured to store the liquefied fuel therein and having a liquid space and a vapor space. The liquefied fuel comprises a liquid phase in the liquid space and a vapor phase in the vapor space. The inlet is connected with the liquid space via a first control valve, and is configured to discharge the liquefied fuel to a first vehicle with a liquid onboard storage system through a first nozzle.

[0017] In some embodiments, the inlet is configured to be fluidly connected to a liquid delivery tanker truck fluidly via a second control valve, and is configured to transfer the liquefied fuel from the liquid delivery tanker truck to the cryotank. The outlet is configured to provide the liquefied fuel to the vapor space via a third control valve or to the liquid space via a fourth control valve of the cryotank.

[0018] In some embodiments, the pump is a low-pressure, high flow reciprocating piston pump. The pump has a maximum discharge pressure of 25 bar(g) (2.5 MPa), and a flow rate up to 150 gpm. The pump may be a single acting or a double acting pump. In each cycle of operation, a reciprocating pump has an extend stroke and a retract stroke with piston moving in two different directions. A “single acting” pump discharges flow only in the extend stroke, whereas a “double acting” pump discharges flow in both extend and retract strokes.

[0019] The peak-to-average ratio of the flow rate of the pump is less than 1.2 in some embodiments. This ratio is computed by identifying the instantaneous peak flow rate, averaging the output flow over time, and taking the ratio of the peak value to the average value. As a reference, a perfectly smooth flow has a peak-to-average ratio of 1.0.

[0020] In another aspect, the present disclosure provides a system comprising the pump as described herein. In accordance with some embodiments, the system comprises a cryotank, a first pump, a first control valve, a second control valve, and a third control valve.

[0021] The cryotank is configured to store a liquefied fuel therein and having a liquid space and a vapor space. The liquefied fuel comprising a liquid phase in the liquid space and a vapor phase in the vapor space. The liquefied fuel comprises or is liquid hydrogen in some embodiments.

[0022] The first pump comprises an inlet, an outlet, and a plurality of single-piston elements, which are configured to accept a liquefied fuel from the inlet and provide a first discharge at the outlet. The plurality of single-piston elements are arranged mechanically or controlled electronically to achieve a flow rate and a pressure. The flow rate is selected from at least two different predetermined flow rates. The pressure is selected from at least two different predetermined pressures. The flow rate has a peak-to-average ratio less than 1.6 for a smooth operation.

[0023] The first pump is configured to be fluidly connected with the liquid space via the first control valve so as to provide the liquid phase of the liquefied fuel for fueling a first vehicle with a liquid onboard storage system though a first nozzle.

[0024] The inlet is configured to be fluidly connected to a liquid delivery tanker truck fluidly via the second control valve, and is configured to transfer the liquefied fuel from the liquid delivery tanker truck to the cryotank. The outlet is configured to be fluidly connected to the cryotank and provide the liquefied fuel to the vapor space via the third control valve or to the liquid space via the fourth control valve.

[0025] In some embodiments, the first pump further comprises a crank shaft, and the plurality of single-piston elements are mechanically connected with the crank shaft in parallel.

[0026] In some embodiments, the first pump further comprises a gear, and the plurality of single-piston elements are mechanically connected eccentrically.

[0027] In some embodiments, each of the plurality of single-piston elements is connected with a respective drive and synchronized via electronic controls.

[0028] In some embodiments, the first pump is a low-pressure, high flow reciprocating piston pump, and / or the first pump has a maximum discharge pressure of 25 bar(g), and a flow rate up to 150 gpm. The first pump may be a single acting or a double acting pump. The flow rate has a peak-to-average ratio less than 1.2 in some embodiments.

[0029] In some embodiments, the system further comprises a second pump and a fifth control valve, the second pump configured to be fluidly connected with the first pump via the fifth control valve to accept the first discharge from the first pump so as to provide a second discharge in a cryo-compressed form for fueling a second vehicle with a cryo-compressed fuel onboard storage system through a second nozzle.

[0030] The system also further comprises at least one gas conditioning device, which comprises either or both of a vaporizer and a heat exchanger, and is configured to convert the second discharge from the second pump into a third discharge in a compressed gas form for fueling at least one vehicle with a compressed gas fuel onboard storage system.

[0031] In some embodiments, the cryo-compressed (cc) fuel onboard storage system is configured to accept ccH2. The at least one vehicle with a compressed gas fuel onboard storage system comprises a third vehicle with a H35 fuel onboard storage system configured to accept H35 compressed hydrogen, and a fourth vehicle with a H70 fuel onboard storage system configured to accept H70 compressed hydrogen, and the refueling station is configured to convert and dispense the third discharge to the third vehicle through a third nozzle and to the fourth vehicle through a fourth nozzle. The third nozzle and the fourth nozzle may be the same nozzle or different nozzles.

[0032] In some embodiments, the second pump is a high-pressure, low flow reciprocating piston pump, and / or has a maximum pressure of 1,000 bar(g) (100 MPa) and a flow rate up to 10 kg / min, preferably 960 bar(g) (96 MPa) and 4 kg / min, and / or the second pump is a single acting or a double acting pump.

[0033] In some embodiments, the system further comprises a controller connected electronically with and configured to individually control each control valve and each dispensing route.

[0034] In another aspect, the present disclosure provides a method of making the pump or the system such as the refueling station as described herein. The method comprises steps of providing components; and assembling the components together to provide the pump or the system.

[0035] In another aspect, the present disclosure provides a method of using the pump or the system. Such a method comprises a step of determining a type of fuel onboard storage system of a vehicle. The type of fuel onboard fuel storage system is selected from at least two different types of fuel onboard storage systems. The method further comprises fueling a type of fuel corresponding to the type of fuel onboard storage system to the vehicle. The type of fuel onboard storage system is selected from a liquid hydrogen onboard storage system, a cryo-compressed H2 system, a H35 fuel onboard storage system, and a H70 fuel onboard storage system. The method comprises the steps of controlling the control valves as described herein.

[0036] Other features of the system and the methods as described herein.BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The present disclosure is best understood from the following detailed description when read in conjunction with the accompanying drawings. It is emphasized that, according to common practice, the various features of the drawings are not necessarily to scale. On the contrary, the dimensions of the various features are arbitrarily expanded or reduced for clarity. Like reference numerals denote like features throughout specification and drawings.

[0038] FIGS. 1 A-1B illustrate examples of discharge profiles of a multi-unit pump such as a duplex pump in some embodiments.

[0039] FIGS. 2A-2C illustrate an exemplary pump comprising a plurality of piston pump elements in three exemplary arrangements in accordance with some embodiments.

[0040] FIG. 3 illustrates an exemplary system comprising an exemplary pump in accordance with some embodiments. The exemplary system is in a cryotank filling mode.

[0041] FIG. 4 illustrates the exemplary system of FIG. 3 in a mode of fueling a liquid onboard vehicle in accordance with some embodiments.

[0042] FIG. 5 illustrates the exemplary system of FIG. 3 in a booster pump mode, in which the exemplary pump is used as a booster pump, in accordance with some embodiments.DETAILED DESCRIPTION

[0043] This description of the exemplary embodiments is intended to be read in connection with the accompanying drawings, which are to be considered part of the entire written description. In the description, relative terms such as “lower,” “upper,” “horizontal,” “vertical,”, “above,” “below,” “up,” “down,” “top” and “bottom” as well as derivative thereof (e.g., “horizontally,” “downwardly,” “upwardly,” etc.) should be construed to refer to the orientation as then described or as shown in the drawing under discussion. These relative terms are for convenience of description and do not require that the apparatus be constructed or operated in a particular orientation. Terms concerning attachments, coupling and the like, such as “connected” and “interconnected,” refer to a relationship wherein structures are secured or attached to one another either directly or indirectly through intervening structures, as well as both movable or rigid attachments or relationships, unless expressly described otherwise.

[0044] For purposes of the description hereinafter, it is to be understood that the embodiments described below may assume alternative variations and embodiments. It is also to be understood that the specific articles, compositions, and / or processes described herein are exemplary and should not be considered as limiting.

[0045] In the present disclosure the singular forms “a,” “an,” and “the” include the plural reference, and reference to a particular numerical value includes at least that particular value, unless the context clearly indicates otherwise. When values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another embodiment. As used herein, “about X” (where X is a numerical value) preferably refers to ±10% of the recited value, inclusive. For example, the phrase “about 8” preferably refers to a value of 7.2 to 8.8, inclusive. Where present, all ranges are inclusive and combinable. For example, when a range of “1 to 5” is recited, the recited range should be construed as including ranges “1 to 4”, “1 to 3”, “1-2”, “1-2 & 4-5”, “1-3 & 5”, “2-5”, and the like. In addition, when a list of alternatives is positively provided, such listing can be interpreted to mean that any of the alternatives may be excluded, e.g., by a negative limitation in the claims. For example, when a range of “1 to 5” is recited, the recited range may beconstrued as including situations whereby any of 1, 2, 3, 4, or 5 are negatively excluded; thus, a recitation of “1 to 5” may be construed as “1 and 3-5, but not 2”, or simply “wherein 2 is not included.” It is intended that any component, element, attribute, or step that is positively recited herein may be explicitly excluded in the claims, whether such components, elements, attributes, or steps are listed as alternatives or whether they are recited in isolation.

[0046] The word “tank” or “cryotank” or “vessel” may be used interchangeably.

[0047] Hydrogen storage includes at least four types including cryogenic hydrogen storage (liquid hydrogen storage), subcooled liquid hydrogen (SLH2) storage, cryocompressed hydrogen (CCH2) storage, and compressed hydrogen storage in an order of increasing pressure. The term “cryogenic hydrogen storage” refers to liquid hydrogen being stored at a cryogenic temperature and a low pressure. One of disadvantages of cryogenic hydrogen storage is the inevitable boil-off losses. The term “subcooled liquid hydrogen (SLH2)” refers to liquid hydrogen stored at a higher pressure, for example, in a range from 1 MPa to 2 MPa (e.g., 1.6 MPa). The term “compressed hydrogen storage” refers to compressed hydrogen gas stored under ambient temperature but at a high pressure, for example, between 300 bar (30 MPa) and 1000 bar (100 MPa). The term “cryo-compressed hydrogen (ccH2) storage” refers to hydrogen being stored at a lower pressure, for example, between 300 bar (30 MPa) and 500 bar (50 MPa), but at low, cryogenic temperatures. The term “cryo-compressed hydrogen (ccH2)” used herein refers to hydrogen stored or dispensed at a pressure equal to or less than 450 bar (45 MPa).

[0048] Hydrogen dispensing described herein includes at least four types including SLH2, ccH2, H35, and H70. The term “H35” means that hydrogen is dispensed at a nominal pressure of 350 bar(g) (35 MPa). The term “H70” means that hydrogen is dispensed at a nominal pressure of 700 bar(g) (70 MPa). Hydrogen may be dispensed at any other pressure coded as “Hn,” where n refers to the pressure in MPa.

[0049] In FIGS. 2-5, like items are indicated by like reference numerals, and for brevity, descriptions of the structure, provided above with reference to the preceding figures, are not repeated. The methods described herein are described with reference to the exemplary structure described in FIGS. 2-5.

[0050] Hydrogen is an energy carrier that can be used as a fuel for transportation. In transportation, hydrogen can be used to power vehicles with fuel cell drive systems or internal combustion engines that run on hydrogen.

[0051] Options for storing the fuel on-board include: (1) as a compressed gas at 35 or 70 MPa; (2) as a cryocompressed fluid at certain pressure; or (3) as liquid hydrogen. Thestorage pressure for such a cryocompressed fluid is between 300 bar to 500 bar (30 MPa to 50 MPa), and temperature between 30 to 80 K. In all three cases, the storage and delivery of hydrogen in liquid form at the station can offer advantages in vehicle refueling. For compressed gas, the use of LH2 facilitates pressurization and pre-cooling of the gas so as to reduce energy demand of the fueling station equipment, allow for faster refueling, and allow for extended vehicle throughput (back-to-back fueling). For cryocompressed and LH2 onboard storage modes, the use of LH2 simplifies the refueling equipment, and allows rapid vehicle refueling.

[0052] Liquid hydrogen (LH2) storage together with a liquid pump has proven to be a low-cost hydrogen dispensing option for hydrogen fuel cell electrical vehicles. Compared to the gaseous hydrogen option, liquid storage has a much lower unit cost of storage so that more hydrogen can be stored at the same cost as high-pressure gas. Liquid pumping is up to 10 times more energy efficient than gas compression. Although hydrogen liquefaction is energy intensive, the subsequent savings in transport costs and station dispensing costs along the supply chain outweigh the initial production cost, and liquid hydrogen has become the preferred choice in most of the newly built stations. However, a significant boiloff occurs during the storage of liquid hydrogen. As the storage tank pressure increases, the boiloff vapor has to be vented through a safety relief valve if not used. A system with minimal boiloff is needed. Alternatively, a system to recycle and / or use the boiloff gas is also desirable.

[0053] A limitation of the LH2 approach is that liquefaction is a complex process, and industrial liquefaction plants are constructed at large scale (>10 tons per day) for energy efficiency. Hydrogen refueling stations that are smaller than this size will require the construction of a smaller and less efficient liquefier, or the delivery of LH2 to onsite storage tanks. In addition, if the refueling profile (e.g., vehicles per hour) is uneven, the refueling station would experience inefficiencies in performance and H2 losses associated with start-up and cycling of equipment. Additional cycling could also increase maintenance requirements and cost.

[0054] The need is for a system that has the ability to deliver hydrogen in three forms - compressed gas, cryo-compressed (supercritical fluid), and liquid - to provide flexibility for hydrogen refueling stations throughout their entire operating cycle. The pump, the system, and the method provided in the present disclosure are developed to meet such a need.

[0055] The phase, pressure, and flow requirements of the three forms fall within various ranges for feasibility, and the current art uses separate pumping systems to deliver the required discharge: a. compressed gas - 35 or 70 MPa, 233K (-40°C) to ambient, 1 to 10 kg / min; b. ccH2 / supercritical - 30-40 MPa, 33K-233K (-40°C), 1 to 10 kg / min; c. LH2 (liquid onboard or sLH2) - less than 25 bar, 20-33K, 20 kg / min; and d. LH2 (stationary tank refill or offloading) - less than 10 bar, 100 gallons / min (25 kg / min).

[0056] The discharge pressure requirements for Scenarios (c) and (d) are similar. Thus, a single pump can serve both functions in some embodiments. Similarly, the same pump can serve as the first-stage booster pump to support Scenarios (a) and (b) to deliver fluid to the suction site of the high-pressure pump to guarantee net positive suction pressure (NPSP) and avoid cavitation in some embodiments.

[0057] Scenario (d) represents an additional relevant scenario since LH2 is delivered to a refueling station by a tanker truck or liquid hauler. The existing practice is to boil off some LH2 to increase the headspace pressure in the tanker. At the same time, the headspace pressure in the station cryotank is reduced by venting. The relative pressure gradient provides a driving force for fluid transfer. Continued pressure adjustment results in additional LH2 loss from the tanker and venting from the receiving cryotank. At the end of the LH2 transfer, the headspace vapor in the tanker is vented to reduce its pressure to a level necessary for on-road transport in the tanker. This process results in significant LH2 losses during the refilling of the stationary cryotank, as high as 20% of the LH2 delivered, or up to 1000 kg for a 4000 kg refill of a 50,000-gal cryotank, as described in International Application No. PCT / US2023 / 027245. A different mechanism for transferring LH2 for refilling the stationary cryotank would have benefits in reducing LH2 losses and needs a high-flow transfer pump.

[0058] Theoretically, a single pump capable of delivering high pressure at lower flow structurally can be operated at lower pressure to deliver high flow at a higher cycle rate within the same power rating. However, the power requirement for a single piston H70 pump with pump discharge pressure at 960 barg (96 MPa) at 10 kg / min is 246 kW on average, and 773 kW peak. Such high power supply can be difficult to obtain and requires prolonged permitting and / or expensive electrical infrastructure upgrades.

[0059] Furthermore, in a two-stage arrangement where a low-pressure pump supplies a downstream high-pressure pump, synchronization of the piston movements of the twopumps is required. Currently, industry uses a centrifugal pump as the first stage. Although a centrifugal pump does not present the piston synchronization problem, it requires a dozen stages or more to achieve the required discharge pressure for the low-density liquid hydrogen fluid and the efficiency is extremely low.

[0060] An integrated pump system that can receive LH2 and deliver H2 in any of the selected forms in the range of flow, pressure, and temperature windows relevant to hydrogen refueling is needed. Such a system would have value in vehicle refueling, and the ability to further integrate cryotank refilling is needed to offer the simplest and most effective system.

[0061] In accordance with some embodiments, the present disclosure provides a multi-role pump, a method of making such a pump, and a method of using such a pump. The pump is configured to be used for multiple roles, for example: (1) as a transfer pump for zeroloss transfer; (2) as a liquid onboard fueling pump; and (3) as a booster pump for higher pressure fueling such as H35, H70 and ccH2 operation. The disclosed method is to use multiple single-piston elements to achieve the desired flow rate, solve the synchronization problem, and stay within reasonable power demand. Such a single-piston pump, which is a pump with a direct drive linear motor, is disclosed in a co-pending U.S. Provisional Patent Application No. 63 / 655,337, filed June 3, 2024 by the same inventors, as the fundamental building element. This application is incorporated herein by reference. By operating multiple single-piston pumps and using switching valves, the multi-role pump can be used for different roles, thus simplifying refueling station design and saving significant capital.

[0062] A duplex, triplex or high number of units can be combined to create a high flow. See Henshaw, T.L., “Displacement pumps,” Chapter 14.1 in Marks’ Standard Handbook for Mechanical Engineers, Eleventh Edition, 2007, McGraw-Hill, New York, p. 15, FIG. 14.1.16. Henshaw describes a system with multiple pistons each with a sinusoidal profile, as would be generated in a crankshaft arrangement. A crankshaft is a device that converts rotating motion into reciprocating motion.

[0063] In the pump provided in the present disclosure, multiple single elements are used to solve the synchronization problem and lead to lower boil-off The state-of-the-art avoids the synchronization problem by using a centrifugal pump which has low efficiency. For example, a state-of-the-art 12-stage centrifugal turbo pump for liquid hydrogen has efficiencies of 41% to 46%, due in large part to the low density of the liquid hydrogen fluid. Pumping efficiency is defined as the ratio of discharge fluid enthalpy gain over the intake condition to drive system power input, commonly known as shaft power. Since the high- pressure pump is a reciprocating piston pump, it takes in fluid only half the cycle, but when itis in the suction stroke, it needs twice the average flow. As a result, the first stage booster pump must provide more than the average flow to ensure sufficient intake for the high- pressure pump. The excess flow is returned to the cryotank, along with the added heat from the booster pump. The inefficiency of the centrifugal pump significantly increases the heat addition and creates boil-off loss. In the end, the centrifugal booster pump solves the cavitation problem but creates a boil-off problem.

[0064] The pump, the resulting system, and the method provide significant technical benefits. For example, a multi-role pump simplifies refueling station design and reduces capital cost and maintenance cost, and reduces boil-off loss. A simplified design also leads to higher reliability of the refueling station. Both cost and reliability are key metrics for better refueling stations, leading to lower cost at the dispenser for the customer and better economic outcome for the station owner.

[0065] As described in Henshaw, the peak-to-average ratio for a single piston with sinusoidal output profile is 3.14. With a duplex arrangement, the ratio improves to 1.57, and it improves further to 1.05 for a triplex arrangement. That is, a triplex pump produces nearly uniform output flow. Because reciprocating piston pumps routinely achieves efficiencies in the 80% to 90% range, a multi-element pump can be used as a booster pump without a synchronization problem. Such a multi-element reciprocating pump, when used as a booster pump, reduces heat input to the fluid thus boil-off loss. Taking the example earlier about 10 kg / min flow and a discharge pressure of 960 barg (96 MPa), a triplex arrangement would need three single-piston elements, each 3.33 kg / min, and a peak power demand of 258 kW. That’s just one-third the peak power demand of a single, large-piston pump. Furthermore, the output is nearly constant with an average output at 95.6% of peak value.

[0066] For a 10 bar, 100 gallons / min (25 kg / min) transfer pump, a triplex arrangement would need three 8.5 kg / min single-piston elements, and a peak power of 17.8 kW at a 25-bar (2.5 MPa) design discharge pressure. This triplex pump can easily operate at a slightly turndown flow rate of 20 kg / min to serve as a booster pump.

[0067] Although theoretically it is possible to operate the high-pressure pump to deliver 25 kg / min at 25 barg (2.5 MPa) discharge pressure at a much lower peak power demand of 17.82 kW, the required pump speed would be more than double which may be undesirable for pump life. Thus, a booster-transfer pump combination with a separate high- pressure second-stage pump is a better arrangement to cover the spectrum of operation.

[0068] Disclosed so far is a sinusoidal pump discharge profile as expected from a crankshaft drive arrangement. With electronic control for a linear motor as disclosed in a co-pending U.S. Provisional Patent Application No. 63 / 655,337, filed June 3, 2024 (disclosing a pump with a direct drive linear motor), or a hydraulically driven pump, the discharge profile can be non-sinusoidal. During the intake portion of the stroke, it is beneficial to quickly open the intake valve to reduce pressure loss through the intake system which could lead to cavitation. At the beginning of the discharge stroke, it is also desirable to open the discharge valve quickly by faster piston motion to reduce exit losses. Such piston motion profile optimization becomes available with electronic controls.

[0069] For an example of piston motion optimization, using a trapezoidal profile with a 5% start ramp and a 10% end ramp as shown in FIG. 1 A, the peak-to-average ratio for a duplex is 1.08 with the same power demand for a simplex. Such a duplex pump output profile is shown in FIG. IB. However, a triplex arrangement would increase the peak power demand to two times the simplex and the peak-to-average ratio is 1.44. Thus, profile optimization can provide another dimension in managing pump flow and power demand.

[0070] The single-piston elements can be mechanically arranged in line with a crankshaft like an automobile engine or circular with an eccentric cam gear like a rotary plunger or swashplate as shown in FIG. 14.1.32 and FIG. 14.1.33 (Henshaw, T.L., “Displacement pumps,” Chapter 14.1 in Marks’ Standard Handbook for Mechanical Engineers, Eleventh Edition, 2007, McGraw-Hill, New York, p. 27.), or electronically synchronized using linear motors as disclosed in the co-pending U.S. Provisional Patent Application No. 63 / 655,337, filed June 3, 2024 (disclosing a pump with a direct drive linear motor). The elements of such an exemplary pump are further illustrated in FIG. 2.

[0071] Referring to FIG. 2 A, in a first embodiment, the multi-role pump 420 comprises three single piston pump elements 421 connected via crankshaft 422. The phase shift among the elements is built into the mechanical crankshaft. A single-piston element includes a single piston reciprocating pump having an inlet and an outlet with the capability of increasing the fluid pressure from the inlet level to the desired outlet level. Such singlepiston elements can be any suitable conventional single-piston pumps available in the market.

[0072] Referring to FIG. 2B, in a second embodiment, the three single piston pump elements 431 are connected via an eccentric gear 423, which drives the pistons radially.

[0073] Referring to FIG. 2C, in a third embodiment, each of the three single piston pump elements 421 has its own drive 424. These drives 424 are electronically connected via wires 426 to an electronic controller 425, which synchronizes the piston element motion. These pump elements can be more flexibly controlled.

[0074] In all embodiments as shown in FIGS. 2A-2C, each pump element 421 is fluidly connected to liquid hydrogen supply source at an inlet, and each is discharged through an outlet. The inlets may be branched off from a single source, and the outlets may be combined into a single stream. Whereas the piston motion in a single element 421 in FIG. 2A and FIG. 2B are mechanically controlled to be substantially sinusoidal, such motion is more flexible with the electronic control in FIG. 2C. Furthermore, the electronic controller may selectively switch on a subset of elements 421 to produce the desired output requirements, or to isolate an element for maintenance. In all configurations, multiple elements combine to work as a whole to provide the desired flow and pressure requirements. Although three elements are shown in FIGS. 2A-2C, more or less elements can be used depending on the specific flow requirements.

[0075] FIGS. 2A-2C are shown for illustration only. Three single piston pump elements 421 for the multi-role pump 420 are illustrated, while more than three or less than three single piston pump elements can be possibly used too.

[0076] FIGS. 3-5 illustrate an exemplary system 110 comprising the exemplary pump 420 as described herein, and the exemplary system in three different operation modes. Pump 420 is a multi-role pump because it serves as a liquid transfer pump in offloading operation, a liquid onboard (sLH2) fueling pump, and a booster pump to support the high-pressure pump 20. The high-pressure pump 20 may not be considered as a multi-role pump because some existing refueling stations have dual pressure dispensing capabilities (H35 and H70) using a single high-pressure pump. Such dual pressure dispensing capability is achieved by simply reducing the discharge pressure of the high pressure pump.

[0077] Referring to FIG. 3, in accordance with some embodiments, the multi-role pump is used in an exemplary system such as an exemplary refueling station. A stationary cryotank 10 has a vapor space 12 and a liquid space 11. The liquid space 11 may supply liquid such as liquid hydrogen to pump 420 via valve 410 and directly fills a liquid onboard vehicle 400. A pressure relief valve 401 is set at the correct pressure to guarantee safe operation.

[0078] Alternatively, the discharge from the pump 420 may supply the suction fluid to pump 20 through valve 450. The discharge from pump 20 may fill vehicles with ccH2, H35 and H70 onboard storage systems 100. A pressure relief valve 101 is set to the desired pressure for safe operation.

[0079] Yet another mode of operation is to supply pump 420 from a liquid hydrogen delivery tanker truck 500 via valve 510. The discharge from pump 420 feeds the diffuser 550in the vapor space 12 in the stationary cryotank 10 via valve 520 and valve 530 as a top-fill commonly known in the industry, or to the liquid space 11 at the bottom of the cryotank 10 via valve 540 as a bottom-fill, in a manner required to achieve the desired zero-loss transfer operation.

[0080] Referring to FIG. 3, the operation is for zero-loss liquid transfer operation in some embodiments. The blacked-out valves indicate closed position. Arrows indicate flow direction. Compound lines with a thicker middle line and two thin outer lines indicate vacuum insulated piping. Valves 530 and 540 are both open as indicated to show the zeroloss transfer process requires switching between top-fill and bottom-fill to achieve the desired cryotank 10 pressure.

[0081] As described herein, the pump 420 is a multi-role low-pressure pump, whereas pump 20 is a high-pressure multi-role pump. As an exemplary design for the low-pressure pump 420, a single-acting reciprocating pump with triplex arrangement, each single piston having a diameter of 80 mm, stroke length 60 mm, operating at 500 cycles per minute (cpm), would provide 100 gpm (~25 kg / min at liquid density of 65 kg / m3) flow rate at a maximum discharge pressure of 25 bar(g). Such a triplex pump would draw on average 16.7 kW power and a peak demand of 17.8 kW. For a typical design for a high-pressure pump to support H70 fueling, a single-acting reciprocating pump with piston diameter of 40 mm, stroke length 60 mm, operating at 500 cpm, would provide 2.2 kg / min flow at a liquid density of 65 kg / m3at a maximum discharge pressure of 960 bar(g). Such a pump would draw on average 54.3 kW power and a peak demand of 170.5 kW.

[0082] Referring to FIG. 4, the multi-role pump 420 is in a liquid onboard fueling mode in some embodiments. Here, the liquid delivery tanker truck is no longer present, and the transfer connection is capped 560. Liquid from the liquid space 11 in the cryotank 10 enters pump 420 via open valve 410 and discharges to onboard vehicle storage system 400 via pressure relief valve 401. All other flow paths are closed.

[0083] Referring to FIG. 5, the multi-role pump (420) is in a booster pump mode in some embodiments. The liquid delivery tanker truck is no longer present, and the transfer connection is capped 560. Liquid from the liquid space 11 in the cryotank 10 enters pump 420 via open valve 410 and discharges to the suction side of the high-pressure pump 20 via open valve 450. The high-pressure pump 20 fuels vehicles with H35, H70 and ccH2 storage systems (100) as appropriate, through properly set pressure relief valve 101. All other flow paths are closed. As a booster pump, pump 420 discharges at a pressure below the hydrogen critical pressure value (approximately 12 barg or 1.2 MPa), and serves as the first stage of thetwo-stage compression process, where the second stage is through the high-pressure pump 20. The main purpose of a booster pump is to increase the pressure of the fluid entering the high-pressure pump above its saturation pressure so that cavitation is avoided. It is noted that excess flow from the booster pump, as discussed earlier, is returned to the cryotank but is not shown for clarity.

[0084] In FIGS. 2-5, the compound lines indicate vacuum jacketed piping. The single lines indicate uninsulated piping. Those with ordinary skills in the art also recognize that valves, equipment, instruments that are not essential to the description of this invention are not shown for clarity.

[0085] The current practice for supporting different pumping needs such as LH2 transfer, liquid onboard, ccH2, H35 and H70 is to use multiple dedicated pumps separately. Such cryogenic pumps are expensive. Because the high-pressure pump is a reciprocating piston pump, a centrifugal booster pump is used to avoid the synchronization problem. But the low efficiency centrifugal booster pump creates excessive boil-off loss. In the present disclosure, by combining the function of a transfer pump and a booster pump together, the multi-role pump disclosed herein achieves the desired high flow rate, solves the synchronization problem, reduces boil-off loss, and stays within reasonable power demand. In the present disclosure, one of the unexpected and surprisingly good results is that the replacement of the centrifugal pump by the disclosed multi-role pump reduces boil-off loss. This multi-role pump also reduces the number of pumps used in a refueling station which lowers capital cost, reduces maintenance and improves reliability. As evidenced by the name, a multi-role pump is one that performs multiple roles or functions without changing its construction. The multiple roles are accomplished by switching valves to create different flow paths or by operating the same equipment at different parameters such as discharge pressure or cycle rate. The benefit is that the same capital equipment is used for different outputs whereas each output used to require a piece of dedicated equipment. In the existing technologies, there is a synchronization issue with the downstream high-pressure pump. In the present disclosure, this synchronization problem is avoided by using a multi-piston pump so that its flow is uniform. But compared to the pumps such as a centrifugal pump, the pump disclosed herein has much higher efficiency, thus lowers boil-off of hydrogen.

[0086] In another aspect, the present disclosure also provides a system such as a refueling station comprising the pump as described herein.

[0087] In some embodiments, the system such as the refueling station further comprises a controller connected electronically with and configured to individually controlthe control valves such as the first control valve, the second control valve, the third control valve, the fourth control valve, the fifth control valve, and each dispensing route. The electronic connection may be made through wire or wirelessly, and may be controllable through cloud operations.

[0088] In another aspect, the present disclosure provides a method of making the pump or the system such as the refueling station as described herein. The method comprises steps of providing components; and assembling the components together to provide the pump or the system.

[0089] In another aspect, the present disclosure provides a method of using the pump or the system. Such a method comprises a step of determining a type of fuel onboard storage system of a vehicle. The type of fuel onboard fuel storage system is selected from at least two different types of fuel onboard storage systems. The method further comprises fueling a type of fuel corresponding to the type of fuel onboard storage system to the vehicle. The type of fuel onboard storage system is selected from a liquid hydrogen onboard storage system, a cryo-compressed H2 system, a H35 fuel onboard storage system, and a H70 fuel onboard storage system. The method comprises the steps of controlling the control valves as described herein.

[0090] The controller is used for controlling the steps of the method including selection of the device and the amount of the material flow in each step or going through each component. The control unit(s) may be electronically connected with the related components in the system. The control unit may comprise one or more processors and at least one tangible, non-transitory machine readable medium encoded with one or more programs to be executed by the one or more processors. The control unit is configured to coordinate with each component so as to control the operation for selecting top fill and bottom fills for liquid offloading, discharging liquid to refuel fuel cell electric vehicles, monitoring safety, and so on.

[0091] The methods and system described herein may be at least partially embodied in the form of computer-implemented processes and apparatus for practicing those processes. The disclosed methods may also be at least partially embodied in the form of tangible, nontransient machine-readable storage media encoded with computer program code. The media may include, for example, RAMs, ROMs, CD-ROMs, DVD-ROMs, BD-ROMs, hard disk drives, flash memories, or any other non-transient machine-readable storage medium, or any combination of these mediums, wherein, when the computer program code is loaded into and executed by a computer, the computer becomes an apparatus for practicing the method. Themethods may also be at least partially embodied in the form of a computer into which computer program code is loaded and / or executed, such that the computer becomes an apparatus for practicing the methods. When implemented on a general-purpose processor, the computer program code segments configure the processor to create specific logic circuits. The methods may alternatively be at least partially embodied in a digital signal processor formed of application specific integrated circuits for performing the methods. The methods may partially or fully be performed through cloud operations as well.

[0092] The references described herein are incorporated herein by reference.

[0093] Although the subject matter has been described in terms of exemplary embodiments, it is not limited thereto. Rather, the appended claims should be construed broadly, to include other variants and embodiments, which may be made by those skilled in the art.

Claims

What is claimed is:

1. A pump, comprising: an inlet; an outlet; and a plurality of single-piston elements configured to accept a liquefied fuel via the inlet and discharge the liquefied fuel via the outlet, the plurality of single-piston elements arranged mechanically or controlled electronically to achieve a flow rate and a pressure, wherein the flow rate is selected from at least two predetermined different flow rates, the pressure is selected from at least two predetermined different pressures, the flow rate has a peak-to-average ratio less than 1.6 for a smooth operation, and the pumping efficiency is at least 70%.

2. The pump of claim 1, wherein the plurality of single-piston elements are arranged in parallel.

3. The pump of claim 2, further comprising a crank shaft, wherein the plurality of singlepiston elements are mechanically connected with the crank shaft.

4. The pump of claim 1, further comprising a gear, wherein the plurality of single-piston elements are mechanically connected eccentrically.

5. The pump of claim 1, wherein each of the plurality of single-piston elements is connected with a respective drive and synchronized electronically.

6. The pump of claim 1, wherein the inlet is configured to be fluidly connected to a cryotank configured to store the liquefied fuel therein and having a liquid space and a vapor space, the liquefied fuel comprising a liquid phase in the liquid space and a vapor phase in the vapor space, wherein the inlet is connected with the liquid space via a first control valve, andconfigured to discharge the liquefied fuel to a first vehicle with a liquid onboard storage system through a first nozzle.

7. The pump of claim 6, wherein the inlet is configured to be fluidly connected to a liquid delivery tanker truck fluidly via a second control valve, and configured to transfer the liquefied fuel from the liquid delivery tanker truck to the cryotank.

8. The pump of claim 7, wherein the outlet is configured to provide the liquefied fuel to the vapor space via a third control valve or to the liquid space via a fourth control valve of the cryotank.

9. The pump of claim 8, wherein the liquefied fuel comprises or is liquid hydrogen.

10. The pump of claim 1, wherein the pump is a low-pressure, high flow reciprocating piston pump.

11. The pump of claim 1, wherein the pump is a high-pressure, low flow reciprocating piston pump.

12. The pump of claim 1, wherein the pump has a maximum discharge pressure of 25 bar(g) (2.5 MPa), and a flow rate up to 150 gpm.

13. The pump of claim 1, wherein the pump has a maximum discharge pressure of 1,000 bar(g) (100 MPa), and a flow rate between 1 kg / min and 25 kg / min, preferably between 2 kg / min and 10 kg / min.

14. The pump of claim 1, wherein the pump is a single acting or a double acting pump.

15. The pump of claim 1, wherein the peak-to-average ratio of the flow rate is less than 1.2.

16. A system, comprising a cryotank configured to store a liquefied fuel therein and having a liquid space and a vapor space, the liquefied fuel comprising a liquid phase in the liquid space and a vapor phase in the vapor space; a first pump, the first pump comprising an inlet, an outlet, and a plurality of singlepiston elements configured to accept a liquefied fuel from the inlet and provide a first discharge at the outlet, the plurality of single-piston elements arranged mechanically or controlled electronically to achieve a flow rate and a pressure, wherein the flow rate is selected from at least two different predetermined flow rates, the pressure is selected from at least two different predetermined pressures, and the flow rate has a peak-to-average ratio less than 1.6 for a smooth operation, where the at least two different flow rates and at least two different pressures define at least two operations generally accomplished by at least two sets of equipment; a first control valve, the first pump configured to be fluidly connected with the liquid space via the first control valve so as to provide the liquid phase of the liquefied fuel for fueling a first vehicle with a liquid onboard storage system though a first nozzle; a second control valve, wherein the inlet is configured to be fluidly connected to a liquid delivery tanker truck fluidly via the second control valve, and configured to transfer the liquefied fuel from the liquid delivery tanker truck to the cryotank; and a third control valve and a fourth control valve, wherein the outlet is configured to be fluidly connected to the cryotank and provide the liquefied fuel to the vapor space via the third control valve or to the liquid space via the fourth control valve.

17. The system of claim 16, wherein the first pump further comprises a crankshaft, and the plurality of single-piston elements are mechanically connected with the crankshaft in parallel.

18. The system of claim 16, wherein the first pump further comprises a gear, and the plurality of single-piston elements are mechanically connected eccentrically.

19. The system of claim 16, wherein each of the plurality of single-piston elements is connected with a respective drive and synchronized electronically.

20. The system of claim 16, wherein the liquefied fuel comprises or is liquid hydrogen.

21. The system of claim 16, wherein the first pump is a low-pressure, high flow reciprocating piston pump, and / or the first pump has a maximum discharge pressure of 25 bar(g) (2.5 MPa), and a flow rate up to 150 gpm.

22. The system of claim 16, wherein the first pump is a single acting or a double acting pump, and / or the flow rate has a peak-to-average ratio less than 1.2.

23. The system of claim 16, further comprising: a second pump and a fifth control valve, the second pump configured to be fluidly connected with the first pump via the fifth control valve to accept the first discharge from the first pump so as to provide a second discharge in a cryo-compressed form for fueling a second vehicle with a cryo-compressed fuel onboard storage system through a second nozzle; and at least one gas conditioning device comprising either or both of a vaporizer and a heat exchanger, and configured to convert the second discharge from the second pump into a third discharge in a compressed gas form for fueling at least one vehicle with a compressed gas fuel onboard storage system.

24. The system of claim 23, wherein the cryo-compressed (cc) fuel onboard storage system is configured to accept ccH2, the at least one vehicle with a compressed gas fuel onboard storage system comprises a third vehicle with a H35 fuel onboard storage system configured to accept H35 compressed hydrogen, and a fourth vehicle with a H70 fuel onboard storage system configured to accept H70 compressed hydrogen, and the refueling station is configured to convert and dispense the third discharge to the third vehicle through a third nozzle and to the fourth vehicle through a fourth nozzle.

25. The system of claim 23, wherein the second pump is a high-pressure, low flow reciprocating piston pump, and / or has a maximum pressure of 1,000 bar(g) (100 MPa) and a flow rate up to 10 kg / min, preferably 960 bar(g) (96 MPa) and 4 kg / min, and / or the second pump is a single acting or a double acting pump.

26. The system of claim 16, further comprising a controller connected electronically with and configured to individually control each control valve and each dispensing route.

27. A method of making the pump or the system of any of the preceding claims, comprising: providing components; and assembling the components together to provide the pump or the system.

28. A method of using the system of any of the preceding claims, comprising: determining a type of fuel onboard storage system of a vehicle, the type of fuel onboard fuel storage system selected from at least two different types of fuel onboard storage systems; fueling a type of fuel corresponding to the type of fuel onboard storage system to the vehicle, wherein the type of fuel onboard storage system is selected from a liquid hydrogen onboard storage system, a cryo-compressed H2 system, a H35 fuel onboard storage system, and a H70 fuel onboard storage system.

Images