Hydrogen applications for turboexpander machines.

Abstract

The apparatus includes a generator including a fluid inlet configured to receive hydrogen at a first pressure, a turbine wheel configured to expand the hydrogen and rotate in response to the expansion of the hydrogen entering through the inlet and exiting through the outlet, a rotor connected to the turbine wheel and configured to rotate therewith, a stationary stator, the generator generating alternating current upon rotation of the rotor within the stator, and a fluid outlet configured to output hydrogen at a second pressure lower than the first pressure. The apparatus includes a power electronics system electrically connected to an electrical output of the generator to receive the alternating current from the generator. The power electronics can regulate the generated current and power various types of loads.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. patent application Ser. No. 17 / 957,971, filed Sep. 30, 2022, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to the use of hydrogen in turboexpander machines. [Background technology]

[0003] Large and complex transportation systems are used to efficiently and effectively move gas from production areas to consumption areas. Gas transported in pipelines can be pressurized and can travel long distances through pipelines under high pressure. Hydrogen, for example, is a rapidly expanding global energy storage market. Hydrogen is used in many manufacturing processes, from oil refining to food processing. Hydrogen is also used as a fuel source for gas turbines and in a wide range of fuel cells for power generation in the industrial and civil transportation sectors. Other gases, such as propane, oxygen, and carbon dioxide, can also be transported through pipelines under high pressure. Summary of the Invention

[0004] An aspect of the embodiment relates to an apparatus including a generator including a fluid inlet configured to receive hydrogen at a first pressure, a turbine wheel configured to expand the hydrogen and rotate in response to the expansion of hydrogen entering the inlet and exiting the outlet, a rotor connected to the turbine wheel and configured to rotate therewith, a stationary stator, the generator generating an alternating current upon rotation of the rotor within the stator, and a fluid outlet configured to output hydrogen at a second pressure lower than the first pressure. The apparatus also includes a power electronics system electrically connected to an electrical output of the generator to receive the alternating current from the generator.

[0005] In some embodiments, the fluid outlet is connected to a fuel cell inlet of the fuel cell, the fluid outlet being configured to direct hydrogen gas at the second pressure to the fuel cell.

[0006] In some embodiments, the power electronics are electrically connected to the fuel cell, and the power electronics are configured to condition the alternating current to have a frequency and amplitude suitable for powering the fuel cell.

[0007] In some embodiments, the fluid outlet is connected to a gas turbine inlet of the gas turbine, the fluid outlet being configured to direct the hydrogen gas at the second pressure to the gas turbine.

[0008] In some embodiments, the fluid inlet is configured to receive hydrogen gas at a first pressure from a trailer container, and the fluid outlet is configured to output hydrogen gas at a second pressure to a compressor of a hydrogen gas storage facility.

[0009] In some embodiments, the power electronics are electrically connected to the compressor, and the power electronics are configured to condition the alternating current to have a frequency and amplitude suitable for powering the compressor.

[0010] In some embodiments, the fluid inlet is configured to receive cooled heat exchange fluid from a first heat exchanger device of the hydrogen liquefaction system at a first pressure, and the fluid outlet is configured to output expanded heat exchange fluid to a second heat exchanger of the hydrogen liquefaction system at a second pressure.

[0011] In some embodiments, the power electronics are electrically connected to one or more compressors of the first or second heat exchanger, and the power electronics are configured to condition the alternating current to have a frequency and amplitude suitable for powering the one or more compressors.

[0012] In some embodiments, the power electronics are electrically connected to one or more compressors of a pre-cooling heat exchanger of the liquefaction system, and the power electronics are configured to condition the alternating current to have a frequency and amplitude suitable for powering the one or more compressors.

[0013] In some embodiments, the power electronics include a variable speed drive connected to the electrical output of the generator, the variable speed drive converting alternating current received from the generator into alternating current compatible with the power grid.

[0014] In some embodiments, the variable speed drive includes a rectifier that receives AC current from the generator and converts the AC current to DC current, and an inverter that receives the DC current from the rectifier and converts the DC current to AC current having an amplitude and frequency compatible with the power grid.

[0015] In some embodiments, the generator includes a three-phase permanent magnet synchronous generator. In some embodiments, the generator includes a three-phase electrical output and the brake resistor assembly includes a brake resistor connected in series with each phase of the electrical output.

[0016] Aspects of the embodiment include a method including receiving hydrogen gas at a first pressure into a turbine wheel of a generator, where receiving the hydrogen gas into the turbine wheel at the first pressure causes the turbine wheel to rotate and expand the hydrogen gas; causing the rotation of the turbine wheel to rotate a rotor within a stator of the generator; causing the rotation of the rotor within the stator to generate an electric current in the generator; directing the electric current generated by the generator to power electronics; and outputting the hydrogen gas at a second pressure lower than the first pressure.

[0017] Some embodiments include outputting the hydrogen gas at a second pressure to a fuel cell.

[0018] Some embodiments include conditioning the current by power electronics so that it is suitable for powering a fuel cell, and directing the conditioned current to the fuel cell.

[0019] Some embodiments include receiving hydrogen gas at a first pressure from a trailer container and outputting the hydrogen gas at a second pressure to a compressor of a hydrogen gas storage facility.

[0020] Some embodiments include adjusting the current by power electronics to suitably power the compressor.

[0021] Some embodiments include receiving a cooled heat exchange fluid at a first pressure from a first heat exchanger of a hydrogen liquefaction system and outputting an expanded heat exchange fluid at a second pressure to a second heat exchanger of the hydrogen liquefaction system.

[0022] Some embodiments include using power electronics to condition the current to have a frequency and amplitude suitable for powering one or more compressors of a hydrogen liquefaction system. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is a schematic diagram of a power generation system connected to a power grid, according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a schematic diagram of a hydrogen decompression system including a turboexpander according to an embodiment of the present disclosure. [Figure 3] FIG. 3 is a process flow diagram for operating a turboexpander for high pressure hydrogen gas decompression according to an embodiment of the present disclosure. [Figure 4] FIG. 4 is a schematic diagram of a hydrogen fuel gas system including a turboexpander according to an embodiment of the present disclosure. [Figure 5] FIG. 5 is a process flow diagram for expanding hydrogen fuel gas using a turboexpander according to an embodiment of the present disclosure. [Figure 6A] FIG. 6A is a schematic diagram of a hydrogen storage vessel system including a turboexpander according to an embodiment of the present disclosure. [Figure 6B] FIG. 6B is a graphical representation of the change in hydrogen pressure in a hydrogen trailer container and hydrogen storage system according to an embodiment of the present disclosure. [Figure 7] FIG. 7 is a process flow diagram for transferring hydrogen from a trailer container to a storage tank using a turboexpander according to an embodiment of the present disclosure. [Figure 8] FIG. 8 is a schematic diagram of a hydrogen production system including a turboexpander according to an embodiment of the present disclosure. [Figure 9] FIG. 9 is a process flow diagram for producing hydrogen using a turboexpander according to an embodiment of the present disclosure. [Figure 10] FIG. 10 is a schematic diagram of a hydrogen liquefaction system including a turboexpander according to an embodiment of the present disclosure. [Figure 11] FIG. 11 is a process flow diagram for hydrogen liquefaction using a turboexpander according to an embodiment of the present disclosure.

[0024] Like reference symbols in different drawings indicate like elements. The drawings are not to scale. DETAILED DESCRIPTION OF THE INVENTION

[0025] The turboexpanders described herein can be used in a variety of hydrogen applications. Turboexpanders process high-pressure hydrogen and convert the pressure energy into electricity for use in a variety of applications. Examples of applications in which turboexpanders can be implemented include pipeline piping depressurization, hydrogen production, hydrogen fuel gas for gas turbines and combustion engines, hydrogen dispensing from trailers, and hydrogen liquefaction. Each of these applications provides sufficient pressure drop and flow rate to operate and produce energy using the turboexpanders described herein.

[0026] The power grid that the turboexpander may supply power to (and draw power from) may be a national or regional power grid, a city or district local power grid, or a small-scale grid, local grid, or microgrid (e.g., an on-site grid that supplies power to a building, campus, industrial manufacturing or processing plant, or its vicinity).

[0027] FIG. 1 is a schematic diagram of a power generation system 100 connected to a power grid 140 according to an embodiment of the present disclosure. The power generation system 100 may be added to a PLD station to recover energy from gas expansion from the PLD process, or any of the other applications described above. The power generation system 100 includes a turboexpander 102 in parallel with a pressure control valve 130. The turboexpander 102 is axially positioned such that the turboexpander 102 is mounted in-line with piping. The turboexpander 102 functions as a generator by generating electrical energy from rotational kinetic energy obtained from the expansion of gas through a turbine wheel 104. For example, rotation of the turbine wheel 104 can be used to rotate a rotor 108 within a stator 110, thereby generating electrical energy.

[0028] FIG. 1 is a schematic diagram of a power generation system 100 connected to a power grid 140 according to an embodiment of the present disclosure. The power generation system 100 can be added to a PLD station to recover energy from the expansion of gas from the PLD process. The power generation system 100 includes a turboexpander 102 in parallel with a pressure control valve 130. The turboexpander 102 is axially positioned such that the turboexpander 102 is mounted in-line with piping. The turboexpander 102 functions as a generator by generating electrical energy from the rotational kinetic energy obtained from the expansion of gas through a turbine wheel 104. For example, the rotation of the turbine wheel 104 can be used to rotate a rotor 108 within a stator 110, thereby generating electrical energy.

[0029] The turboexpander 102 is shown with the process gas flowing through the system, which cools the generator section and eliminates the need for auxiliary cooling. In some embodiments, a non-flow-through overhung system may also be implemented. The turboexpander's power electronics 118, in some embodiments, integrates a variable speed drive (VSD) 166 and a magnetic bearing controller (MBC) 168 into a single cabinet. The VSD allows the turboexpander 102 to provide uniform, clean power to the power grid 140. The VSD 166 adjusts the frequency and amplitude of the generated current to match the local grid. After expansion, the gas exits the turboexpander 102 along the same axial path for downstream processing.

[0030] The turboexpander 102 is shown as having a flow-through configuration. The flow-through configuration allows process gas to flow from the inlet side of the turboexpander 102 to the outlet side of the turboexpander 102. The gas enters the turbine wheel 104 through a radial gas inlet 154 and exits the turbine wheel 104 through an axial gas outlet 156. The gas then flows through a generator and exits through the outlet 156 before rejoining the gas pipeline 170. Generally, the high-pressure process gas 120 is directed into the turboexpander 102 through a flow control system 126. The flow control system 126 includes flow or mass control valves and an emergency shut-off valve. The flow control system 126 may be electrically controlled from the power electronics 118 by control line 164. In an embodiment, the turboexpander housing 112 is hermetically sealed. As noted above, the turboexpander may be non-flow-through and overhung without departing from the scope of this disclosure. The high-pressure process gas 120 is expanded by flowing through the turbine wheel 104, resulting in a pressure reduction of the process gas 120. Low-pressure process gas 128 exits the turboexpander. The expansion of the high-pressure process gas 120 through the turbine wheel 104 rotates the turbine wheel 104, which in turn rotates the rotor 108. The rotation of the rotor 108 within the stator 110 generates electrical energy. The turboexpander 102 achieves the desired pressure reduction and extracts energy from the reduced pressure to generate electricity. A pressure control valve 130, such as a conventional pressure regulator, may be installed in parallel with the turboexpander 102. The pressure control valve 130 may be used to control the pressure of the high-pressure process gas 120 flowing through the turboexpander. Excess high-pressure process gas not directed to the turboexpander may be directed through the pressure control valve 130. Additionally, when the turboexpander 102 is shut down, the flow control system 126 may shut off the flow of process gas to the turboexpander. In that case, pressure control valve 130 may be set to reduce the pressure of the high pressure gas for downstream distribution and consumption.

[0031] The flow control system 126 may include pressure relief valves, flow control valves, emergency shut-off valves, etc. Using one or more valves, the flow control system 126 may control the pressure of the hydrogen entering the turbine wheel 104 to achieve both a desired turbine wheel speed (and resulting electrical output) and a desired hydrogen output pressure from the turboexpander 102.

[0032] In some embodiments, a heater 122 can heat the high-pressure process gas 120 before passing the gas to the turboexpander 102. For example, if the expansion of the gas through the turbine wheel 104 reduces the temperature of the process gas and moisture in the gas may freeze at the turbine wheel or at other downstream locations in the pipeline, the pressurized process gas 120 can be heated by the heater 122. The (heated) high-pressure process gas 124 may be directed to the turboexpander 102. Heating the process gas can prevent moisture from freezing as the gas expands and cools.

[0033] The turboexpander 102 includes a turbine wheel 104. While the turbine wheel 104 is shown as a radial-inflow turbine wheel, other configurations, such as an axial-flow turbine wheel, are within the scope of this disclosure. In this example, heated high-pressure process gas 124 is received from an inlet conduit 150 in the housing 112 and enters a radially oriented inlet 154 of the turbine wheel 104. In certain embodiments, the fluid flows through the inlet conduit 150 and is diverted by a flow diverter to the radial inlet 154, which directs the flow to the radial inlet of the turbine wheel 104. After expansion, the lower-pressure process gas exits the turbine wheel 104 through an axially oriented outlet 156 and passes to an outlet conduit 152 in the housing 112.

[0034] The turbine wheel 104 may be directly secured to the rotor 108 or an intermediate common shaft, for example, by fasteners, a rigid drive shaft, welding, or other methods. For example, the turbine wheel 104 may be received at one end of the rotor 108 and held to the rotor 108 by a shaft. The shaft is threaded into the rotor 108 at one end and captures the turbine wheel 104 at the other end between one end of the rotor 108 and a nut threaded onto the shaft. The turbine wheel 104 and rotor 108 are connected without a gearbox and rotate at the same speed. In other cases, the turbine wheel 104 may be indirectly connected to the rotor 108, for example, by a gear train, a clutch mechanism, or other methods.

[0035] The turbine wheel 104 includes a plurality of turbine wheel blades 106 that extend outward from a hub and react with the expanding process gases to rotate the turbine wheel 104. Figure 1 illustrates an unshrouded turbine wheel in which the turbine blades 106 each have an exposed, generally radially oriented blade tip that extends between a radial inlet 154 and an axial outlet 156. As described in more detail below, the blade tips are substantially sealed against a shroud 114 inside a housing 112. In certain cases, the turbine wheel 104 is a shrouded turbine wheel.

[0036] In a configuration with an unshrouded turbine wheel 104, the housing 112 includes an inwardly facing shroud 114 that is adjacent to the turbine wheel blades 106 but generally does not contact the turbine wheel blades 106 during operation. The proximity of the turbine wheel blades 106 and the shroud 114 substantially seals the passage of process gas between the turbine wheel blades 106 and the shroud 114 as the process gas flows through the turbine wheel 104. While some amount of process gas may leak or pass between the turbine wheel blades 106 and the shroud 114, this leakage is not significant to the operation of the turbine wheel 104. In certain cases, leakage may be comparable to other similar unshrouded turbine / shroud surface interfaces using conventional tolerances between the turbine wheel blades 106 and the shroud 114. The amount of allowable leakage may be predetermined. The operating parameters of the turbine generator may be optimized to reduce leakage. In an embodiment, the housing 112 is hermetically sealed to prevent process gases from leaking out of the radial inlet 154 of the turbine wheel 104 .

[0037] The shroud 114 may be spaced a predetermined distance from the turbine wheel blades 106 and is maintained at that distance from the turbine wheel blades 106 during operation of the turboexpander 102 using a magnetic positioning device including active magnetic bearings and position sensors.

[0038] The turboexpander 102 may include a high-performance, high-speed permanent magnet generator. In certain embodiments, the turboexpander 102 includes a radial-inflow expansion turbine wheel 104. The turboexpander 102 may also include low-loss active magnetic bearings (AMBs) 116a,b. The rotor assembly includes a permanent magnet section of the turbine wheel 104 mounted directly to a rotor hub. The rotor 108 may be levitated by the magnetic bearing system, creating a frictionless (or nearly frictionless) interface between the dynamic and static components. The AMBs 116a,b facilitate lossless (or nearly lossless) rotation of the rotor 108.

[0039] The bearings 116a and 116b are positioned to rotatably support the rotor 108 and turbine wheel 104 relative to the stator 110 and shroud 114. The turbine wheel 104 is supported by the bearings 116a and 116b in a non-cantilevered manner. In embodiments, the turbine wheel 104 may be supported in a cantilevered manner, and the bearings 116a and 116b may be positioned on the outlet side of the turbine wheel 104. In certain cases, one or more of the bearings 116a or 116b may include a ball bearing, a needle bearing, a magnetic bearing, a foil bearing, a journal bearing, or the like.

[0040] Bearings 116a and 116b may be a combination radial and thrust bearing that provides radial and axial support for rotor 108. Other configurations are also possible. Bearings 116a and 116b do not have to be the same type of bearing.

[0041] In embodiments in which the bearings 116a and 116b are magnetic bearings, a magnetic bearing controller (MBC) 168 is used to control the magnetic bearings 116a and 116b. The position sensors 117a and 117b may be used to detect the position or change in position of the turbine wheel 104 and / or rotor 108 relative to the housing 112 or other reference point (e.g., a predetermined value). The position sensors 117a and 117b may detect axial and / or radial displacement. The magnetic bearings 116a and / or 116b may respond to information from the position sensors 117a and 117b and adjust the detected displacement as needed. The MBC 168 may receive information from the position sensors 117a and 117b, process the information, and provide control signals to the magnetic bearings 116a and 116b. The MBC 168 may communicate with various components of the turboexpander 102 via the communication channel 162.

[0042] The turboexpander 102 can operate at high efficiency by using the magnetic bearings 116a, 116b and position sensors 117a, 117b to maintain and / or adjust the position of the turbine wheel blades 106 so that they are close to the shroud 114. The use of active magnetic bearings 116a, b in the turboexpander 102 eliminates physical contact between rotating and stationary components and eliminates the need for lubrication and lubrication systems. In some embodiments, brush seals may be used to prevent gas leakage. The magnetic bearings 116a, b and position sensors 117a, b allow the rotor to remain close to the brush seal 157.

[0043] The turboexpander 102 may include one or more backup bearings. For example, during startup and shutdown, or during a power outage affecting the operation of the magnetic bearings 116a and 116b, the bearings may be used to rotatably support the rotor 108 during such periods. The backup bearings may include ball bearings, needle roller bearings, journal bearings, etc. As previously described, the turboexpander 102 is configured to generate electricity in response to the rotation of the rotor 108. In certain cases, the rotor 108 may include one or more permanent magnets. The stator 110 includes multiple conductive coils. Electric current is generated by the rotation of the magnets within the coils of the stator 110. The rotor 108 and the stator 110 may be configured as a synchronous permanent magnet multi-phase alternating current (AC) generator. The bidirectional electrical connection 160 may include, for example, a three-phase output. The bidirectional electrical connection 160 can facilitate the transfer of (e.g., three-phase) electrical power output from the generator and can also power the generator for starting (e.g., to initiate rotor rotation while the pressure of a process gas or other working fluid increases, causing the rotor 108 and turbine wheel 104 to rotate). In certain cases, the stator 110 may include multiple coils (e.g., three or six coils for a three-phase AC output). As the rotor 108 rotates, a voltage is induced in the stator coils. In either example, the magnitude of the voltage induced in the coils is proportional to the rate at which the magnetic field surrounding the coil changes over time (i.e., the rate at which the magnetic field passes on both sides of the coil). When the rotor 108 is connected to rotate at the same speed as the turbine wheel 104, the turboexpander 102 is configured to generate electricity at that speed. Such a turboexpander 102 is referred to as a “high-speed” turbogenerator. For example, in an embodiment, the turboexpander 102 can generate up to 280 kW at a continuous speed of 30,000 rpm. In an embodiment, the turboexpander can generate in the order of 350 kW at higher rotational speeds (e.g., in the order of 35,000 rpm).

[0044] In some embodiments, the design of the turbine wheel 104, rotor 108, and / or stator 110 may be based on desired parameters of the output gases from the turboexpander 102. In some embodiments, the design of the turbine nozzle 155 may be based on desired parameters of the output gases from the turboexpander 102. For example, the design of the turbine nozzle and turbine wheel may be based on a desired temperature of the gases 128.

[0045] The turboexpander 102 may be connected to power electronics 118. The power electronics 118 may include a variable speed drive (VSD) 166 (or variable frequency drive) and a magnetic bearing controller (MBC) 168 (discussed above).

[0046] The bidirectional electrical connection 160 of the turboexpander 102 is connected to a VSD 166, which can be programmed for specific power requirements. The VSD 166 may include an insulated-gate bipolar transistor (IGBT) rectifier 208 that converts the variable frequency high voltage output from the turboexpander 102 to direct current (DC). The rectifier 208 may be a three-phase rectifier for three-phase AC input current. An inverter 210 converts the DC from the rectifier to AC for supply to the power grid 140. The inverter 210 may convert the DC to 380 VAC to 480 VAC at 50-60 Hz for supply to the power grid 140. The specific output of the VSD 166 depends on the power grid and application. Other conversion values ​​are within the scope of this disclosure. The VSD 166 matches its output to the power grid 140 by sampling the grid voltage and frequency and changing the inverter's output voltage and frequency to match the sampled grid voltage and frequency. In an embodiment, the rectifier 208 and inverter 210 are bidirectional so that power from the grid 140 can be supplied to the turboexpander 102. The power from the grid 140 can be used to initiate rotation of the rotor 108 within the stator 110 during start-up.

[0047] The turboexpander 102 is also connected to the MBC 168 within the power electronics 118. The MBC 168 constantly monitors position, current, temperature, and other parameters to ensure that the turboexpander 102 and the active magnetic bearings 116a and 116b are operating as desired. For example, the MBC 168 is connected to position sensors 117a and 117b to monitor the radial and axial positions of the turbine wheel 104 and rotor 108. The MBC 168 can control the magnetic bearings 116a and 116b to selectively vary the stiffness and damping characteristics of the magnetic bearings 116a and 116b as a function of spin speed. The MBC 168 can also control desynchronization, which can include auto-balancing control, adaptive vibration control, adaptive vibration cancellation, and unbalanced force cancellation control.

[0048] The pressure reduction system converts the kinetic energy of the process stream into shaft power. The turboexpander can support islanding operations. The turboexpander can continue to power a location even if the power grid supplying the location is interrupted. This disclosure describes components that can facilitate load matching between the shaft power converted from the process gas stream at the pressure reduction station and the load demand. In this manner, the turboexpander can support microgrid functionality for islanding operations.

[0049] The turboexpander 102 described above includes example implementation-specific features. Specific features may be modified, added, removed, or redesigned without departing from the scope of this disclosure. Other types of bearings, such as ball bearings, fluid film bearings, etc., may be used instead of or in addition to AMBs. Various rotor and stator designs may be used, such as brushless DC, induction, etc. Other types of stator cooling configurations may also be used, such as non-flow-through, overhanging, etc.

[0050] Distribution pipelines have the highest gas flow rates in the distribution network and therefore the greatest potential for turboexpander-based pressure reduction. Both natural gas and hydrogen pressure reduction stations can utilize multiple turboexpander units in parallel to maximize power generation (although the illustration shows only one turboexpander). The potential power generation in high-flow applications is up to 3 megawatts (MW), equivalent to a reduction in CO2 emissions of approximately 12,000 tons per year.

[0051] The hydrogen is compressed for passage through the pipeline, and as the hydrogen flows from high pressure to low pressure, the pressure of the hydrogen is reduced along the pipeline. During the reduction in distribution pressure (e.g., using a pressure reducing device (PLD) or pressure reducing station (PRS)), usable energy can be recovered by the turboexpander 102 to generate clean electricity. Such a topology is shown generally in Figure 1 above and more specifically in Figure 2.

[0052] FIG. 2 is a schematic diagram of a hydrogen decompression system 200 including a turboexpander 102 according to an embodiment of the present disclosure. The hydrogen decompression system 200 includes the turboexpander 102 or a similar turboexpander. The turboexpander 102 receives high-pressure hydrogen gas 222 from a pipeline, for example, as part of a hydrogen gas decompression process. The high-pressure hydrogen gas may enter the turboexpander's turbine wheel. The high-pressure hydrogen gas may rotate the turbine wheel, which may then rotate a rotor within a stator. The rotation of the rotor within the stator may generate an electric current. The electric current may be output from the turboexpander to power electronics 118. The power electronics 118 may convert the electric current to meet the grid 140 or other electrical loads. This electricity may be consumed on-site by the facility, consumed on-site in an energy-intensive process such as green hydrogen production, or sold to a local energy utility, providing a source of revenue for the pipeline owner.

[0053] The high-pressure hydrogen gas 222 may travel through a pipeline and enter the hydrogen pressure reduction system 200. The hydrogen pressure reduction system 200 includes a flow control system (e.g., flow control system 126 in FIG. 1 ) and a pressure control valve 130 (also shown in FIG. 1 ). The flow control system 126 may include a flow control valve (FCV) 240 and an emergency shut-off valve (ESV) 242. The FCV 240 may control the pressure of the flow of high-pressure hydrogen gas 222 entering the turboexpander 102. The flow rate of the high-pressure hydrogen gas 222 may be controlled by the FCV 240 based on the size of the turbine wheel 104 and the desired power output of the power electronics 118, and the rotational speed of the rotor 108 may be determined based on the desired rotational dynamic performance of the rotor 108. The FCV 240 may be manually or electronically controlled. The FCV 240 may be electronically controlled, for example, based on information regarding the power output of the power electronics 118. If the power output is too low, the FCV 240 can be adjusted to increase the flow rate of high-pressure hydrogen gas 222 entering the turboexpander 102 and increase the torque of the rotor 108; conversely, if the power output is too high, the FCV 240 can be adjusted to decrease the flow rate of high-pressure hydrogen gas 222 entering the turboexpander 102 and decrease the torque of the rotor 108.

[0054] The flow control system 126 may also include an ESV 242 that can be rapidly closed to prevent high-pressure hydrogen gas 222 from entering the turboexpander 102 during an emergency situation, which may include a rotor overspeed condition, a hydrogen gas leak, a fault condition in the power electronics 118 or grid 140 or elsewhere (which may cause a rotor overspeed), or other emergency situation.

[0055] The turboexpander 102 may expand the high-pressure hydrogen gas 222 to generate low-pressure (or lower-pressure) hydrogen gas 224. The low-pressure hydrogen gas 224 may be directed to a downstream pipeline or other location for distribution. The expansion of the high-pressure hydrogen gas 222 by the turbine wheel 104 of the turboexpander 102 generates an electric current. The electric current may be output by the turboexpander 102 to the power electronics 118 through the two-way electrical connection 160. The power electronics 118 may convert the generated electric current to a form compatible with the intended consumer of the electric current. For example, the power electronics 118 may change the amplitude and frequency of the generated electric current to suit the power supply to the grid 140 or an electrical load.

[0056] The power electronics 118 may include a variable speed drive (VSD) 206. The VSD 206 may include circuitry that can modify the current to suit a particular load or grid. For example, the VSD 206 may include circuitry that can convert the generated current from AC to DC (e.g., a rectifier circuit) and circuitry that can convert DC to AC (e.g., an inverter circuit). The VSD 206 may include a bidirectional inverter that allows the turboexpander to receive power from the grid for starting. The VSD 206 may also include circuitry that modifies the waveform of the generated current to adapt the current to have a frequency and amplitude that is compatible with the power grid 140. Other electrical circuits are contemplated and within the scope of this disclosure.

[0057] The power electronics 118 may include a brake resistor assembly 202. The brake resistor assembly 202 may be used to counteract runaway current generation during a rotor overspeed condition, reducing rotor rotational speed and preventing rotor damage. The brake resistor assembly 202 may be connected to the bidirectional electrical connection 160 by a contactor 204. The contactor 204 may quickly close a circuit between the turboexpander power output and the brake resistor upon detection of an overspeed condition to protect the rotor. The impedance of the brake resistor assembly may be selected (or adjusted) based on the turboexpander power output. The brake resistor assembly may include multiple resistors (or, in some cases, resistors and capacitors). While shown as part of the power electronics 118, it is understood that the brake resistor assembly 202 and contactor 204 may be connected directly to the output of the turboexpander 102, thereby reducing the latency between detection of a fault condition causing a rotor overspeed and closing of the contactor 204.

[0058] 3 is a process flow diagram 300 for operating a turboexpander for depressurizing high-pressure hydrogen gas according to an embodiment of the present disclosure. High-pressure hydrogen gas is injected into the turbine wheel of the turboexpander (302). The high-pressure hydrogen gas injected into the turbine wheel may rotate the turbine wheel, which may then rotate a rotor within a stator (304). The turbine wheel also expands the high-pressure hydrogen gas, thereby reducing the pressure of the hydrogen gas. This low-pressure (or lower-pressure) hydrogen gas is output from the turboexpander for downstream distribution and consumption (306).

[0059] The current generated by the turboexpander may be output to a power electronics system, which may condition the current to match the intended load or to supply the grid (308). The power electronics system may output the conditioned current to the intended load or to the grid (310).

[0060] It is understood that the sequence of operations shown in FIG. 3 (or other process flow diagrams described herein) can be performed in an alternate order. Some processes are performed in parallel. For example, as the rotor of the turboexpander rotates at a constant speed with a constant torque, the turboexpander generates an electric current. The flow of hydrogen gas can be continuous, maintaining a desired power output from the power electronics. While the rotor rotates at the desired speed, the expanded hydrogen gas is output from the turboexpander and directed downstream, and an electric current is output from the power electronics. These processes of generating an electric current in the turboexpander from the expansion of high-pressure hydrogen gas can continue until the system is shut down for some reason.

[0061] 2 can be used in combination with other hydrogen applications. In general, the turboexpander 102 can be used to expand high-pressure hydrogen gas 222 to output lower-pressure hydrogen gas 224 and generate electrical current.

[0062] 4 is a schematic diagram of a hydrogen-based power plant 400 including a turboexpander 102 according to an embodiment of the present disclosure. Hydrogen is used to generate electricity in a gas turbine (such as gas turbine 410) or a fuel cell (such as fuel cell 412). Both applications use large amounts of hydrogen, which is supplied via a pipeline from an on-site storage facility or an associated production facility. Before the hydrogen enters the gas turbine 410 or fuel cell 412, the pressure in the pipeline or storage facility is reduced (i.e., reduced). The turboexpander 102 can be used to recover energy from the pressure reduction of the hydrogen fuel gas.

[0063] Depending on the circumstances, volumetric flow rates for these applications can be in the order of 1,000-5,000 Nm3 / h. Potential recoverable power ranges from 10 kW up to 300 kW, sufficient to improve overall plant efficiency. An example use of the generated power is to offset the electrical demand of a facility. The economic benefit or return on investment can then be assessed using the retail price of electricity, rather than the wholesale price of selling electricity to the grid.

[0064] Initially, high-pressure hydrogen gas 404 is delivered to the hydrogen-based power plant 400 from a hydrogen fuel gas source 402. The hydrogen fuel gas source may include a hydrogen storage tank or a hydrogen pipeline. The hydrogen-based power plant 400 includes a flow control system 126 and a pressure control valve 130. As previously described, the flow control system 126 includes the FCV 240 and the ESV 242. The flow control system 126 may control the flow of the high-pressure hydrogen fuel gas 404 to the turbine wheel 104 of the turboexpander 102. The turbine wheel 104 of the turboexpander 102 may expand and reduce the pressure of the high-pressure hydrogen fuel gas 404. The low-pressure (or lower-pressure) hydrogen fuel gas 406 may be supplied to a hydrogen-based power system 408, such as a gas turbine 410 or a fuel cell 412. The hydrogen-based power system 408 may provide power to a grid or to one or more loads.

[0065] Energy recovered from the reduction in pressure of the high-pressure hydrogen fuel gas 404 by the turbine wheel 104 is used to generate electrical current. The expansion of the high-pressure hydrogen fuel gas 404 rotates the turbine wheel 104, which in turn rotates the rotor 108. The rotation of the rotor 108 within the stator 110 generates electrical current. The electrical current can be used to power a specific load, such as a load at a power plant facility, or can be used to power the grid. For example, the electrical current generated by the turboexpander 102 can be routed to power electronics 118 (described above). The power electronics 118 can include circuitry to condition the generated electrical current to suit the load or the grid. The power electronics 118 can also condition the electrical power generated by the turboexpander 102 to a frequency and amplitude compatible with the gas turbine 410 or the fuel cell 412.

[0066] Figure 5 is a process flow diagram for expanding hydrogen fuel gas using a turboexpander according to an embodiment of the present disclosure. High-pressure hydrogen fuel gas is injected into a turbine wheel of the turboexpander (502). The high-pressure hydrogen fuel gas injected into the turbine wheel may rotate the turbine wheel, which may then rotate a rotor within a stator (504). The turbine wheel also expands the high-pressure hydrogen fuel gas, thereby reducing the pressure of the hydrogen fuel gas. This low-pressure (or lower-pressure) hydrogen fuel gas is output from the turboexpander for downstream distribution and consumption (506).

[0067] The current generated by the turboexpander can be output to power electronics, which can regulate the current to meet an intended load or to supply the grid (508). The power electronics can output the regulated current to the intended load or to the grid (510).

[0068] 6A is a schematic diagram of a hydrogen fueling station 600 including a turboexpander according to an embodiment of the present disclosure. Hydrogen gas may be transported in a bulk delivery trailer from an origination point to the hydrogen fueling station 600. The hydrogen gas is unloaded from a hydrogen gas trailer container 602 into an on-site storage vessel 614 at the fueling station 600 where it is stored until dispensed into a consumer's vehicle. While a global hydrogen pipeline infrastructure is being constructed and implemented, using trailers to transport the hydrogen gas is useful.

[0069] These large-capacity trailers deliver gaseous hydrogen 604 at high pressure (approximately 700 bar), which is pumped into a storage vessel 614 at the hydrogen fueling station 600. This process involves the expansion of the high-pressure hydrogen gas 604. In an embodiment of the present disclosure, a turboexpander 102 is used to control the expansion of the high-pressure hydrogen gas 604 from the trailer container 602 and to recover energy from the expansion of the high-pressure hydrogen gas to generate electrical current. During the early part of the trailer offloading process, when the pressure in the H gas trailer 602 is higher than the pressure in the H gas storage vessel 614, the turboexpander 102 can be used to recover the expansion energy by generating electrical current. This electrical current can be used to offset at least a portion of the electrical demand required to operate the compressor 612, which is used to pump hydrogen gas into the hydrogen gas storage vessel 614 during the later part of the emptying process, when the pressure in the H gas trailer 602 is lower than the pressure in the H gas storage vessel 614.

[0070] First, high-pressure hydrogen gas 604 is delivered to the hydrogen fueling station 600 by a hydrogen gas trailer 602. The hydrogen fueling station 400 includes a flow control system 126 and a pressure control valve 130. As described above, the flow control system 126 includes the FCV 240 and the ESV 242. The flow control system 126 can control the flow of the high-pressure hydrogen gas 604 to the turbine wheel 104 of the turboexpander 102. The turbine wheel 104 of the turboexpander 102 can expand and reduce the pressure of the high-pressure hydrogen gas 604.

[0071] Energy recovered from the decompression of the high-pressure hydrogen gas 604 by the turbine wheel 104 is used to generate electrical current. The expansion of the high-pressure hydrogen gas 604 rotates the turbine wheel 104, which in turn rotates the rotor 108. The rotation of the rotor 108 within the stator 110 generates electrical current. The electrical current can be used to power a specific load, such as the compressor 612, via the battery system 614, or can be used to at least offset the electrical power consumed by the compressor 612 by selling the generated electrical power to the grid or by using the generated electrical power to power other loads at the facility. For example, the electrical current generated by the turboexpander 102 can be routed to the power electronics 118 (described above). The power electronics 118 can include circuitry to condition the generated electrical current to suit the battery system 614, or other loads at the fueling station, or the grid.

[0072] 6B is a graphical representation 620 of hydrogen pressure changes in a hydrogen trailer container and hydrogen storage system according to an embodiment of the present disclosure. As hydrogen pressure drops within the trailer container, a compressor is used to pump hydrogen into the storage tank. The compressor is powered by a turboexpander via a battery system, as shown in FIG. 6A, allowing the storage tank to be filled with pressurized hydrogen at a fueling station.

[0073] 7 is a process flow diagram for transferring hydrogen from a trailer container to a storage tank using a turboexpander according to an embodiment of the present disclosure. High-pressure hydrogen gas is injected from the trailer container into the turbine wheel of the turboexpander (702). The high-pressure hydrogen gas injected into the turbine wheel may rotate the turbine wheel, which may then rotate a rotor within a stator (704). The turbine wheel also expands the high-pressure hydrogen gas, thereby reducing the pressure of the hydrogen gas. This low-pressure (or lower) hydrogen gas is output from the turboexpander to a storage vessel at a fuel distribution station (706).

[0074] The current generated by the turboexpander can be output to power electronics. The power electronics can condition the current to match the supply to a battery system, other utility loads, or the grid (708). The power electronics can output the conditioned current to the battery system, the intended load, or the grid (710). A compressor can be powered using the power generated from the expansion of the hydrogen gas to pump the hydrogen gas to a fuel tank (712).

[0075] 8 is a schematic diagram of a hydrogen production system 800 including a turboexpander 102 according to an embodiment of the present disclosure. The turboexpander 102 can recover energy lost during pressure reduction in natural gas distribution networks. Natural gas distribution is an energy-intensive process that uses multi-megawatt compressors to compress gas and send it through thousands of miles of pipelines. City gate pressure reducing stations (PRS) reduce this pressurized pipeline gas to a pressure suitable for distribution to local businesses, energy production, and homes.

[0076] In a PRS, pressure reduction can be achieved using a turboexpander 102 instead of a pressure reducing valve or a Joule-Thomson (JT) valve. Energy from the expansion of the natural gas can be recovered using the turboexpander 102 and converted into usable electricity.

[0077] Some PRSs are located in remote locations with limited access to the surrounding electrical grid. Therefore, it is desirable to consume the generated electricity on-site. In an embodiment, the electricity generated by the turboexpander 102 can be consumed for green hydrogen production by electrolysis. The electricity generated from the turboexpander 102 can power a bank of electrolyzers that can produce hydrogen and oxygen from water.

[0078] According to the Fuel Cells and Hydrogen Joint Undertaking, polymer electrolyte membrane (PEM) electrolyzer efficiency is currently 70-82% and is expected to reach 86% by 2030. Current PEM technology produces approximately 1 kg of hydrogen per 50 kWh of electricity. Therefore, a 280 kW FIT system producing 2.45 GWh of electricity per year could produce up to 54 tonnes of green hydrogen each year. The production of green hydrogen from clean, renewable energy sources plays an essential role in achieving the goals of the Paris Agreement.

[0079] In FIG. 8 , a hydrogen production system 800 is coupled to a natural gas PRS that connects a pipeline capable of transporting high-pressure natural gas 822. The high-pressure natural gas 822 can be heated using a heater 122. The heated high-pressure natural gas can be directed to a turboexpander 102 through a flow control system 126. The hydrogen production system 800 includes the flow control system 126 and a pressure control valve 130. As previously described, the flow control system 126 includes an FCV 240 and an ESV 242. The flow control system 126 can control the flow of the heated high-pressure natural gas 824 to the turbine wheel 104 of the turboexpander 102. The turbine wheel 104 of the turboexpander 102 can expand and reduce the pressure of the heated high-pressure natural gas 824. The low-pressure (or lower-pressure) natural gas 826 is directed to a pipeline for downstream distribution and consumption.

[0080] Energy recovered by the turbine wheel 104 from the reduction in pressure of the heated high-pressure natural gas 824 is used to generate electrical current. The expansion of the heated high-pressure natural gas 824 rotates the turbine wheel 104, which in turn rotates the rotor 108. The rotation of the rotor 108 within the stator 110 generates electrical current. The electrical current can be used to power the electrolyzer 802 or can at least offset the power consumed by the electrolyzer 802 by selling the generated electrical power to the grid or by using the generated electrical power to power other loads in the hydrogen production station 800. For example, the electrical current generated by the turboexpander 102 can be directed to the power electronics 118 (described above). The power electronics 118 can include circuitry to condition the electrical current generated from the turboexpander to suit the electrolyzer 802, other loads in the hydrogen production system 800, or the grid.

[0081] The electrolyzer 802 can take water as an input and produce hydrogen 804 and oxygen 806 through electrolysis. The hydrogen can then be transported off-site in a trailer or blended into a natural gas pipeline.

[0082] Figure 9 is a process flow diagram for producing hydrogen using a turboexpander according to an embodiment of the present disclosure. High-pressure natural gas is injected into the turbine wheel of the turboexpander (902). As the high-pressure natural gas is injected into the turbine wheel, the turbine wheel rotates, causing a rotor within a stator (904). The turbine wheel also expands the high-pressure natural gas, reducing the pressure of the natural gas. This low-pressure (or lower-pressure) natural gas is output from the turboexpander for downstream distribution and consumption (906).

[0083] The current generated by the turboexpander can be output to power electronics. The power electronics can condition the current to match the electrolyzer of the hydrogen production process system (908). The power electronics can output the conditioned current to power the electrolyzer (910). The electrolyzer can operate to produce hydrogen (912), as described in the text accompanying FIG. 8.

[0084] FIG. 10 is a schematic diagram of a hydrogen liquefaction system 1000 including a turboexpander according to an embodiment of the present disclosure. Hydrogen, like other gases, is most efficiently transported in liquid form. The liquefaction process shown in FIG. 10 can be used to convert hydrogen gas (GH2 1002) to liquid hydrogen (LH2 1004). A series of processes including compression, heat exchange, and expansion are used to reduce the temperature of GH2 1002 to -253°C. The turboexpander 102 can be used to recover energy lost during the expansion of the H2 and the closed-loop heat exchange fluid (hydrogen, helium, nitrogen, etc.).

[0085] The example liquefaction system 1000 shown in Figure 10 uses two heat exchangers (e.g., heat exchanger 1006 and heat exchanger 1008). The heat exchangers reduce the temperature of the incoming GH2 1002 and the outgoing LH2 1004. There may be more than two heat exchangers (or more than two heat exchange processes). This portion of the system may also include other equipment not shown, such as compressors and other devices. Heat exchangers may include pre-cooling heat exchangers, cryogenic heat exchangers, etc.

[0086] The heat exchange system 100 also includes a closed-loop Brayton cycle 1010. The closed-loop Brayton cycle includes a compressor 1006 for compressing a heat exchange fluid. The compressor 1012 directs the heat exchange fluid to a cooler 1014. The cooled heat exchange fluid may be used in the heat exchanger 1006 to cool hydrogen. The turboexpander 102a may be used to further expand and cool the heat exchange fluid for use in the heat exchanger 1008 and to further cool the hydrogen in the heat exchanger 1006. The heat exchange fluid is then directed to the compressor 1012 to continue the Brayton cycle 1010.

[0087] The expansion of the heat exchange fluid by the turbine wheel of the turboexpander 102a may generate electricity. The electrical power generated by the turboexpander 102a from the expansion of the heat exchange fluid may be used to power a load. The power electronics 118 may condition the electricity output by the turboexpander for use by one or more loads. For example, the electricity generated by the turboexpander 102a may be used to power the compressor 1012 (or to offset the electrical power used by the compressor 1012). The turboexpander 102a may also power other loads 1018. Such loads may include other equipment that is part of the liquefaction process, such as the compressors of the heat exchangers 1006, 1008, or other equipment.

[0088] In some embodiments, turboexpander 102b can also be used to generate electricity from the expansion of hydrogen during the liquefaction process. The power generated from the expansion of hydrogen can be used to power electric compressors and other devices.

[0089] FIG. 11 is a process flow diagram for hydrogen liquefaction using a turboexpander according to an embodiment of the present disclosure. As previously described, the liquefaction system includes a heat exchanger and a closed-loop Brayton cycle. The Brayton cycle may include a compressor that compresses a heat exchange fluid (1102). The pressurized heat exchange fluid may be cooled by a chiller (1104). The pressurized and cooled heat exchange fluid may be used in a heat exchanger of the hydrogen liquefaction process (1106). The heat exchange fluid may be expanded by a turbine wheel of the turboexpander (1108). Expansion of the heat exchange fluid by the turbine wheel of the turboexpander reduces the pressure of the heat exchange fluid and rotates a rotor connected to the turbine wheel.

[0090] The expanded heat exchange fluid exits the turboexpander and is returned to the Brayton cycle where it is directed to the heat exchangers of the liquefaction process to cool the hydrogen 1110. The heat exchange fluid is returned to the compressor 1102.

[0091] The rotation of the turboexpander rotor can generate electricity 1112. The electricity can be conditioned by power electronics 1114 to suitably power one or more loads, including one or more compressors and / or heat exchangers of a Brayton cycle. The compressors can be powered (at least in part) by the electricity generated by the turboexpander 1116.

[0092] In some embodiments, the energy lost during the expansion of hydrogen in the liquefaction process can also be used to spin the turbine wheel of a turboexpander to generate electricity, which in turn can be used to operate various loads, including heat exchanger compressors and other devices.

[0093] The use of turboexpander 102 for power generation by gas expansion provides the following advantages to the liquefaction process:

[0094] 1. Magnetic bearings enable operation without oil or air, so there is no contamination from process gases.

[0095] 2. Magnetic bearings enable long life (25 years) and maintenance-free operation.

[0096] 3. The system is designed to provide 125kW or 280kW, making it a convenient, scalable power building block for liquefaction plants.

[0097] 4. Modular design allows for lower capital costs as an alternative to custom-engineered solutions.

[0098] 5. Flow-through design eliminates dynamic sealing and leakage risk.

[0099] 6. Energy balance through generator load design.

[0100] Existing liquefaction plants process up to 40 tons per day (tpd) of liquid hydrogen, producing 400 kW of potential power generation from turboexpander 102. Future liquefaction plants are designed for capacities up to 200 tpd, generating up to 2 megawatts of clean electricity. Based on the Energy Information Administration's 2019 U.S. totals, 2 MW of power generation equates to a reduction of 8,000 tons of carbon dioxide equivalent (CO2e) emissions per year.

[0101] Accordingly, the specification and drawings should be regarded in an illustrative rather than a restrictive sense. Moreover, the use of the aforementioned embodiment and other exemplary language does not necessarily refer to the same embodiment or identical example, but may refer to different, distinct, and potentially identical embodiments. In the foregoing specification, a detailed description has been given with reference to certain exemplary embodiments. It will be apparent, however, that various modifications and changes can be made thereto without departing from the broad spirit and scope of the present disclosure as set forth in the appended claims.

Claims

1. A generator, a fluid inlet configured to receive hydrogen at a first pressure; a turbine wheel configured to expand the hydrogen and rotate in response to the expansion of the hydrogen flowing through its inlet and outlet; a rotor connected to the turbine wheel and configured to rotate with the turbine wheel; a fixed stator in which the generator generates alternating current by rotation of the rotor within the stator; a fluid outlet configured to output the hydrogen at a second pressure lower than the first pressure; a generator including: a power electronics system electrically connected to an electrical output of the generator to receive alternating current from the generator; An apparatus comprising:

2. The apparatus of claim 1 , wherein a fluid outlet is connected to a fuel cell inlet of a fuel cell, the fluid outlet being configured to direct hydrogen gas at the second pressure to the fuel cell.

3. 3. The apparatus of claim 2, wherein the power electronics are electrically connected to the fuel cell, the power electronics being configured to condition the alternating current to have a frequency and amplitude suitable for powering the fuel cell.

4. The apparatus of claim 1 , wherein a fluid outlet is connected to a gas turbine inlet of a gas turbine, the fluid outlet being configured to direct hydrogen gas at the second pressure to the gas turbine.

5. the fluid inlet is configured to receive hydrogen gas at the first pressure from a trailer container; the fluid outlet is configured to output hydrogen gas at the second pressure to a compressor of a hydrogen gas storage facility.

10. The apparatus of claim 1.

6. 6. The apparatus of claim 5, wherein the power electronics is electrically connected to the compressor, the power electronics configured to condition the alternating current to have a frequency and amplitude suitable for powering the compressor.

7. the fluid inlet is configured to receive cooled heat exchange fluid from a hydrogen liquefaction system of a first heat exchanger apparatus at the first pressure; the fluid outlet is configured to output expanded heat exchange fluid to a second heat exchanger of the hydrogen liquefaction system at the second pressure.

10. The apparatus of claim 1.

8. 8. The apparatus of claim 7, wherein the power electronics is electrically connected to one or more compressors of the first heat exchanger or the second heat exchanger, and the power electronics is configured to adjust the alternating current to have a frequency and amplitude adapted to power the one or more compressors.

9. 8. The apparatus of claim 7, wherein the power electronics is electrically connected to one or more compressors of a pre-cooling heat exchanger of the hydrogen liquefaction system, and the power electronics is configured to condition the alternating current to have a frequency and amplitude adapted to power the one or more compressors.

10. 2. The apparatus of claim 1, wherein the power electronics includes a variable speed drive connected to the electrical output of the generator, the variable speed drive converting the alternating current received from the generator to alternating current compatible with a power grid.

11. The variable speed drive a rectifier that receives AC current from the generator and converts the AC current into DC current; an inverter that receives the DC current from the rectifier and converts the DC current into an AC current having an amplitude and frequency compatible with the power grid; The apparatus of claim 10, comprising:

12. The apparatus of claim 1 , wherein the generator comprises a three-phase permanent magnet synchronous generator.

13. 10. The apparatus of claim 1, wherein the generator includes a three-phase electrical output, and the brake resistor assembly includes a brake resistor connected in series with each phase of the electrical output.

14. receiving hydrogen gas at a first pressure into a turbine wheel of a generator, the hydrogen gas being received into the turbine wheel at the first pressure to rotate the turbine wheel and expand the hydrogen gas; rotating the turbine wheel to rotate a rotor within a stator of the generator; generating an electric current in the generator due to rotation of the rotor within the stator; conducting the current generated by the generator to power electronics; and outputting the hydrogen gas at a second pressure lower than the first pressure; A method comprising:

15. The method of claim 14 further comprising outputting hydrogen gas at a second pressure to a fuel cell.

16. 15. The method of claim 14, further comprising: conditioning, by the power electronics, the current suitable for powering a fuel cell; and directing the conditioned current to the fuel cell.

17. receiving the hydrogen gas at the first pressure from a trailer container; and outputting the hydrogen gas at a second pressure to a compressor of a hydrogen gas storage facility; 15. The method of claim 14, further comprising:

18. 18. The method of claim 17, further comprising adjusting, by the power electronics, the current to be suitable for powering the compressor.

19. receiving a cooled heat exchange fluid at the first pressure from a first heat exchanger of a hydrogen liquefaction system; and outputting the expanded heat exchange fluid at the second pressure to a second heat exchanger of the hydrogen liquefaction system; 15. The method of claim 14, further comprising:

20. 20. The method of claim 19, further comprising using power electronics to adjust the current to have a frequency and amplitude suitable for powering one or more compressors of the hydrogen liquefaction system.

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