Fuel cell systems and methods with improved fuel utilization

Abstract

To provide a fuel cell system using or recapturing essentially all of the hydrogen content and nearly all of the carbon content of input fuel provided to the fuel cell system.SOLUTION: A fuel cell system comprises: at least one hot box (100) comprising a fuel cell stack and producing an anode exhaust product; at least one hydrogen pump (408); at least one product conduit (410) fluidly connecting an anode exhaust product outlet of the hot box (100) to an inlet of the hydrogen pump (408); a compressed hydrogen product conduit (410) connected to a compressed hydrogen product outlet of the hydrogen pump; and at least one effluent conduit (418) connected to an unpumped effluent outlet of the hydrogen pump (408).SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] Aspects of the present disclosure relate to fuel cell systems and methods of operating a fuel cell system.

Background Art

[0002] A fuel cell, such as a solid oxide fuel cell, is an electrochemical device that can convert the energy stored in a fuel into electrical energy with high efficiency. High-temperature fuel cells include solid oxide fuel cells and molten carbonate fuel cells. These fuel cells can operate using hydrogen and / or hydrocarbon fuels. There are types of fuel cells, such as solid oxide regenerative fuel cells, that can also operate in reverse, using electrical energy as an input to reduce oxidized fuel back to unoxidized fuel.

Summary of the Invention

[0003] A fuel cell system according to one embodiment includes at least one hot box that includes a fuel cell stack and generates anode exhaust products, at least one hydrogen pump, at least one product conduit fluidly connecting an anode exhaust product outlet of the hot box to an inlet of the at least one hydrogen pump, a compressed hydrogen product conduit connected to a compressed hydrogen product outlet of the at least one hydrogen pump, and at least one effluent conduit connected to an unpumped effluent outlet of the at least one hydrogen pump.

[0004] A fuel cell system in a further embodiment includes a fuel cell stack and at least one hot box that generates anode exhaust products; at least one carbon dioxide pump; at least one product conduit that fluidly connects the anode exhaust product outlet of the hot box to the inlet of the at least one carbon dioxide pump; a compressed carbon dioxide product conduit connected to the compressed carbon dioxide product outlet of the at least one carbon dioxide pump; and at least one fouling conduit connected to the unpumped fouling outlet of the at least one carbon dioxide pump.

[0005] Further embodiments include a method for operating a fuel cell system, comprising the steps of: supplying a fuel intake flow to at least one hot box of the fuel cell system; generating an anode exhaust product flow from the at least one hot box of the fuel cell system; supplying the anode exhaust product flow to at least one hydrogen pump; generating compressed hydrogen products and unpumped effluent in the at least one hydrogen pump; and recirculating at least a portion of the compressed hydrogen products to the at least one hot box of the fuel cell system.

[0006] Further embodiments include a method for operating a fuel cell system, comprising the steps of: supplying a fuel intake flow to at least one hot box of the fuel cell system; generating an anode exhaust product flow from the at least one hot box of the fuel cell system; supplying the anode exhaust product flow to at least one carbon dioxide pump; generating compressed carbon dioxide products and unpumped effluent in the at least one carbon dioxide pump; and recirculating at least a portion of the unpumped effluent from the carbon dioxide pump to the at least one hot box of the fuel cell system. [Brief explanation of the drawing]

[0007] The attached figures, which are incorporated herein and constitute part of this specification, illustrate exemplary embodiments of this disclosure and, together with the above-mentioned general description and the detailed description below, are useful in illustrating the features of this disclosure.

[0008] [Figure 1] Figure 1 is a schematic diagram of a hot box for a solid oxide fuel cell system according to various embodiments. [Figure 2] Figure 2 is a schematic diagram of the components of a fuel cell system according to one embodiment of the present disclosure. [Figure 3] Figure 3 is a schematic diagram of the components of a fuel cell system according to another embodiment of the present disclosure. [Figure 4] Figure 4 is a schematic diagram of the components of a fuel cell system according to yet another embodiment of the present disclosure. [Figure 5] Figure 5 is a schematic diagram of the components of a fuel cell system according to yet another embodiment of the present disclosure. [Figure 6] Figure 6 is a schematic diagram of the components of a fuel cell system according to yet another embodiment of the present disclosure. [Modes for carrying out the invention]

[0009] Various embodiments will be described in detail with reference to the attached drawings. Wherever possible, the same reference numerals will be used throughout the drawings to refer to the same or similar parts. References to specific examples and embodiments are for illustrative purposes only and are not intended to limit the scope of the invention or the claims.

[0010] Figure 1 is a schematic diagram of a hot box 100 of a fuel cell system 10, such as a solid oxide fuel cell (SOFC) system, according to various embodiments of the present disclosure. The hot box 100 may include a fuel cell stack 102, such as a solid oxide fuel cell stack (wherein one solid oxide fuel cell in the stack includes a ceramic electrolyte such as yttria-stabilized zirconia (YSZ) or scandia-stabilized zirconia (SSZ), an anode electrode such as nickel-YSZ or Ni-SSZ cermet, and a cathode electrode such as lanthanum strontium manganite (LSM)). The stacks 102 can be stacked on top of each other to form multiple columns.

[0011] The hot box 100 may also include an anode reheater 110, a cathode reheater 120, an anode tail gas oxidizer (ATO) 130, an anode exhaust cooler 140, a vortex generator 550, and a steam generator 160. The fuel cell system 10 may further include additional components such as a system blower 208 (e.g., an air blower), a water source 206, valves 511 and / or fluid conduits 300D, 302A, 304C, 306 and 308G, which may be located outside or partially outside the hot box 102. However, this disclosure does not limit the location of each component relative to the hot box 102 to any particular location.

[0012] The fuel flow enters the hot box 102 through the fuel conduit 300D and flows to the anode reheater 110. The fuel flow may include a mixture of hydrocarbon fuel such as natural gas, recirculated anode exhaust from the fuel cell system 10, and optionally, recirculated hydrogen products, which will be described in more detail below. The fuel flow may be heated in the anode reheater 110 and may flow from the anode reheater 110 through the fuel conduit 300E to the stack 102.

[0013] The system blower 208 may be configured to supply an airflow (e.g., an air intake flow) to the anode exhaust cooler 140 through the air conduit 302A. Air flows from the anode exhaust cooler 140 through the air conduit 302B to the cathode reheater. Air flows from the cathode reheater 120 through the air conduit 302C to the stack 102.

[0014] The anode exhaust generated in stack 102 is supplied to the anode regenerator 110 through the anode exhaust conduit 308A. The anode exhaust may contain unreacted fuel and is sometimes referred to herein as fuel exhaust. The anode exhaust located within the anode regenerator 110 can transfer heat to the incoming fuel flow that flows through the anode regenerator 110 to stack 102. The anode exhaust can be supplied from the anode regenerator 110 to the anode exhaust conduit 308B. The anode exhaust can flow through the anode exhaust conduit 308B to the anode exhaust cooler 140. The anode exhaust from the anode exhaust cooler 140 can exit the hot box 100 through the anode exhaust conduit 308C. An anode recycle blower (not shown in Figure 1) in fluid communication with the anode exhaust conduit 308C may be configured to move the anode exhaust through the anode exhaust conduit 308C, as will be described in more detail below. In some embodiments, the splitter 511 may be configured to selectively supply a portion of the anode exhaust from the anode exhaust conduit 308C to the anode exhaust conduit 308D. The splitter 511 may be any other suitable fluid splitting device, such as a computer-controlled or operator-controlled valve, or a passive splitter having an opening or slit in the fluid conduit. The anode exhaust conduit 308D can selectively redirect a portion of the anode exhaust leaving the anode exhaust cooler 140 to the ATO 130 through the anode exhaust conduit 308D, for example, during startup of the SOFC system 10 or other transient operating conditions.

[0015] In the embodiment shown in Figure 1, all of the anode exhaust in the hot box 100 passes through the anode exhaust cooler 140 before leaving the hot box 100 through the anode exhaust conduit 308C. In other embodiments described in more detail below, at least a portion of the anode exhaust can leave the hot box 100 before passing through the anode exhaust cooler 140. For example, a portion of the anode exhaust flow can leave the hot box 100 through an anode exhaust conduit (not shown in Figure 1) which may be located between the anode reheater 110 and the anode exhaust cooler 140.

[0016] The cathode exhaust generated in stack 102 flows through exhaust conduit 304A to ATO 130. A vortex generator 550 can be placed within exhaust conduit 304A and configured to swirl the cathode exhaust. An anode exhaust conduit 308D can be fluidly connected downstream of the vortex generator 550 to either the cathode exhaust conduit 304A or ATO 130. The swirled cathode exhaust can be mixed with the anode exhaust from anode exhaust conduit 308D before being supplied to ATO 130. This mixture can be oxidized within ATO 130 to produce ATO exhaust. The ATO exhaust flows from ATO 130 through exhaust conduit 304B to cathode reheater 120. The ATO exhaust flows out of the hot box 100 through exhaust conduit 304C from the cathode reheater.

[0017] Water flows from a water source 206, such as a water tank or water pipe, through a water conduit 306 to the steam generator 160. The steam generator 160 injects water into the anode exhaust conduit 308B. Heat from the anode exhaust supplied to the exhaust conduit 308B from the anode reheater 110 vaporizes this water and generates steam. The steam mixes with the anode exhaust and supplies a humidified anode exhaust flow that flows from the anode exhaust conduit 308B through the anode exhaust cooler 140 to the anode exhaust conduit 308C.

[0018] System 10 may further include a system controller 225 configured to control various elements of System 10. The controller 225 may include a central processing unit configured to execute stored instructions. For example, the controller 225 may be configured to control the flow of fuel and / or air through System 10 according to fuel composition data. System 10 may also include one or more fuel reforming catalysts 112, 114, and 116.

[0019] During operation, stack 102 generates electricity using the supplied fuel and air, producing anode exhaust (i.e., fuel exhaust) and cathode exhaust (i.e., air exhaust). The anode exhaust may contain unreacted hydrocarbon fuels such as hydrogen, water vapor, carbon monoxide, carbon dioxide, methane, and other reaction by-products and impurities.

[0020] Figure 2 is a schematic diagram of the components of a fuel cell system 10 according to an embodiment of the present disclosure. The fuel cell system 10 may include at least one hot box 100, such as the hot box 100 described above with reference to Figure 1. For example, the fuel cell system 10 may include n hot boxes 100, where n is an integer between 1 and 100, such as 2 to 10, for example, 4 to 8. The fuel cell system 10 shown in Figure 2 includes two hot boxes 100, but fuel cell systems according to various embodiments may include more or fewer hot boxes 100.

[0021] FIG. 2 schematically shows the flow of fuel and anode exhaust throughout the fuel cell system 10 according to one embodiment of the present disclosure. Referring to FIG. 2, the system 10 can be connected to a fuel source 400 that can supply a suitable fuel to the fuel cell system 10. The fuel source 400 can include one or more fuel storage containers (e.g., fuel tanks or similar containers) that can be located at the same site as the system 10. Alternatively, the fuel source 400 can supply fuel to the system 10 from a remote fuel source through, for example, a gas utility line. The fuel supplied from the fuel source 400 to the fuel cell system 10 can include any suitable hydrocarbon fuel, including, but not limited to, natural gas, propane, or other biogas containing methane, along with methane, hydrogen, and other gases, or carbon fuels such as carbon monoxide, oxygenated carbon-containing gases such as methanol, or other carbon-containing gases, and hydrogen-containing gases such as steam, H2 gas, or mixtures thereof. For example, the mixture can include syngas derived from the reforming of coal or natural gas.

[0022] In some embodiments, the fuel from the fuel source 400 can undergo one or more pretreatment steps before being supplied to the hot box 100 of the fuel cell system 10. For example, the fuel suction conduit 300A connected to the fuel source 400 can supply fuel to one or more pretreatment units 400, such as one or more desulfurizers, to remove sulfur and / or other undesirable impurities from the fuel stream. The pretreated fuel can then flow through the fuel conduit 308B to each of the hot boxes 100.

[0023] In some embodiments, each hot box 100 can further include a catalytic partial oxidation (CPOx) reactor 200, a mixer 210, a CPOx blower 204 (e.g., an air blower), and an anode recycle blower 212, which can be located outside the hot box 100. However, the present disclosure is not limited to the specific location of each component with respect to the hot box 100.

[0024] Referring again to FIG. 2, each CPOx reactor 200 associated with each hot box 100 can receive an intake fuel flow through fuel conduit 308B. The CPOx blower 204 can supply air to the CPOx reactor 204. Fuel and / or air from the CPOx reactor 200 can be supplied to the mixer 210 by fuel conduit 300C. The mixer 210 can be configured to mix the fuel flow with the recirculated anode exhaust from the hot box 100. This mixture of fresh fuel and recirculated anode exhaust can then be supplied to the hot box 100 through fuel conduit 300D as described above with reference to FIG. 1.

[0025] The anode exhaust (i.e., fuel exhaust) from each hot box 100 can exit the hot box 100 through the anode exhaust conduit 308C as described above with reference to FIG. 1. A splitter 511 (see FIG. 1) can selectively redirect a portion of the anode exhaust located within the anode exhaust conduit 308C back to the hot box 100 through the anode exhaust conduit 308D. As described above, a portion of the anode exhaust redirected through the anode exhaust conduit 308D can be supplied to the ATO 130 of the hot box 100 during startup or other excessive operating conditions.

[0026] In the embodiment shown in Figure 2, the remaining anode exhaust located in the anode exhaust conduit 308C can be supplied to a splitter 403. The splitter 403 may be any other suitable fluid splitting device, such as a computer-controlled or operator-controlled valve, or a passive splitter with an opening or slit in the fluid conduit. The first portion of the anode exhaust can be supplied from the splitter 403 through the anode exhaust conduit 308E to an anode recycle blower 212. The anode recycle blower 212 may be any suitable fluid (e.g., gas) blower, pump, compressor, etc. The first portion of the anode exhaust can be supplied from the anode recycle blower 212 through the anode exhaust conduit 308F to a mixer 210. As described above, the recirculated anode exhaust can be mixed with new fuel in the mixer 210 before being reintroduced to the hot box 100 through the fuel conduit 300D. As used herein, a portion of the anode exhaust that exits the hot box 100 through the anode exhaust conduit 308C, is recirculated by the anode recycle blower 212 and mixed with new fuel in the mixer 210, and re-enters the hot box 100 through the fuel conduit 300D may be called "anode recycle," and the fluid path of the anode recycle between the anode exhaust conduit 308C at the outlet of the hot box 100 and the fuel conduit 300D at the inlet of the hot box 100 may be called the "anode recycle loop."

[0027] A second portion of the anode exhaust can be supplied from the splitter 403 through the anode exhaust conduit 308G to the manifold 104. The manifold 104 can be connected to multiple hot boxes 100 of the system 10 (including, in some embodiments, all of the hot boxes 100 of the system 10) by their respective anode exhaust conduits 308G. Alternatively, the system 10 may include multiple manifolds 104, each manifold 104 may be connected to a subset of the hot boxes 100 of the system 10. In various embodiments, the anode exhaust flows from multiple hot boxes 100 of the system 10 may be combined within the manifold 104.

[0028] Referring again to Figure 2, in some embodiments, each of the hot boxes 100 may include an optional additional anode exhaust conduit 308H that fluidly communicates with the manifold 104. In some embodiments, the optional additional anode exhaust conduit 308H can provide a direct fluid path between the hot box 100 and the manifold 104. In some embodiments, the anode exhaust in the optional anode exhaust conduit 308H can exit the hot box 100 upstream of the anode exhaust cooler 104 (see Figure 1). For example, the hot box 100 may include a splitter (e.g., a valve, a passive splitter, etc.) in the anode fluid conduit 308B located between the anode reheater 110 and the anode exhaust cooler 140 within the hot box 100 as shown in Figure 1. The splitter can redirect a portion of the anode exhaust flow from anode exhaust conduit 308B to an optional anode exhaust conduit 308H, so that this portion of the anode exhaust flow can be directly supplied to the manifold 104 shown in Figure 2. The remaining portion of the anode exhaust flow can proceed through the anode exhaust cooler 140 to the anode exhaust conduit 308C, as described above.

[0029] Therefore, in some embodiments, the anode exhaust supplied to the manifold 104 may include a first component of anode exhaust that exits the hot box 100 at the outlet of the anode exhaust cooler 140 and flows to the manifold 104 through anode exhaust conduit 308C, splitter 511 and / or 403, and anode exhaust conduit 308G, and a second component of anode exhaust that exits the hot box 100 upstream of the anode exhaust cooler 140 and flows to the manifold 104 through anode exhaust conduit 308H. Thus, the second component of anode exhaust can bypass the anode exhaust cooler 140 and therefore can have a higher temperature than the first component of anode exhaust that flows through the anode exhaust cooler 140.

[0030] In some embodiments, the mixture of anode exhaust received by the manifold 104 can be varied so that, for a certain period of time, the larger portion of anode exhaust (including all of the anode exhaust) supplied to the manifold 104 from one or more hot boxes 100 is a first component of anode exhaust supplied through anode exhaust conduit 308G (i.e., anode exhaust that has passed through the anode exhaust cooler 140 of the hot box 100), and for other periods of time, the larger portion of anode exhaust (including all of the anode exhaust) supplied to the manifold 104 from one or more hot boxes 100 is a second component of anode exhaust supplied through anode exhaust conduit 308H (i.e., anode exhaust that bypasses the anode exhaust cooler 140 of the hot box 100). The system controller 225 described above with reference to Figure 1 may be used to control the mixture of the first and second components of anode exhaust supplied to the manifold 104 from each of the hot boxes 100.

[0031] In some embodiments, a first component of the anode exhaust supplied to the manifold 104 through the anode exhaust conduit 308G (i.e., the anode exhaust that has passed through the anode exhaust cooler 140 of the hot box 100) may have a temperature between approximately 100°C and 180°C, and a second component of the anode exhaust supplied to the manifold 104 through the anode exhaust conduit 308H (i.e., the anode exhaust that bypasses the anode exhaust cooler 140 of the hot box 100) may have a temperature between approximately 300°C and 500°C.

[0032] Therefore, the temperature of the anode exhaust in the manifold 104 can be controlled by supplying an anode exhaust flow containing a mixture of a first component of anode exhaust at a lower temperature that passes through the anode exhaust cooler 140 of the hot box 100, and a second component of anode exhaust at a higher temperature that bypasses the anode exhaust cooler 140. In some embodiments, the temperature of the anode exhaust in the manifold 104 can be controlled to contain more heat than is required for the subsequent H2 recovery process and / or carbon dioxide separation process, as will be described in more detail below. Supplying an anode exhaust flow containing excess heat may offer the advantage that the cooling of the anode exhaust required for one or more subsequent processes may consume less parasitic power than is required to heat the anode exhaust for these same processes.

[0033] Referring again to Figure 2, the combined anode exhaust flow from multiple hot boxes 100 can be supplied from the manifold 104 through the anode exhaust conduit 308I to the anode exhaust adjustment unit 404. The anode exhaust adjustment unit 404 can be configured to change the temperature of the anode exhaust flow to make it suitable for introduction into the water-gas shift (WGS) reactor 405 located downstream of the anode exhaust adjustment unit 404. The anode exhaust adjustment unit 404 may include one or more heat transfer devices, such as one or more heat exchangers and / or condensers. Other suitable heat transfer devices are within the expected scope of this disclosure. In some embodiments, if the temperature of the anode exhaust flow is higher than the operating temperature range of the WGS reactor, one or more heat transfer devices may be cooled with a cooling medium, such as cooling water and / or air, to reduce the temperature of the anode exhaust flow flowing through the anode exhaust adjustment unit 404. In other embodiments, if the temperature of the anode exhaust flow is lower than the operating temperature range of the WGS reactor 405, one or more heat transfer devices can transfer heat to the anode exhaust flow to raise the temperature of the anode exhaust flow flowing through the anode exhaust adjustment unit 404. Heat transfer to the anode exhaust flow can be achieved by heat exchange with a fluid medium (e.g., combustion gas) at a higher temperature than the anode exhaust flow, or by directly heating the anode exhaust flow using a heater such as an electric heater. In various embodiments, the temperature of the anode exhaust exiting the anode exhaust adjustment unit 404 may be between approximately 150°C and 300°C, for example, between approximately 200°C and 250°C.

[0034] Referring again to Figure 2, the anode exhaust flow can be supplied from the anode exhaust adjustment unit 404 to the WGS reactor 405 through the anode exhaust conduit 308J. The WGS reactor 405 can be configured to convert CO and H2O in the anode exhaust to CO2 and H2 using a water-gas shift reaction. In various embodiments, the WGS reactor 405 may be a low-temperature WGS reactor 405 and may have a nominal operating temperature between about 200°C and 250°C. After the water-gas shift reaction, the anode exhaust flow mainly consists of H2O, CO2 and H2, and may contain small amounts of CO, N2 and other impurities.

[0035] Next, the anode exhaust flow can be supplied from the WGS reactor 405 to the condenser 406 through the anode exhaust conduit 308K. The condenser 406 is cooled by a cooling medium such as cooling water and / or air to condense the water vapor into liquid water, thereby lowering the temperature of the anode exhaust flow to below 100°C, for example, between 50°C and 80°C (e.g., ~70°C). The liquid water can be removed from the condenser 406 through the water discharge conduit 407, and the liquid water in the conduit 407 can optionally be purified and / or reused. In various embodiments, water knockout can be incorporated into the design of the condenser 406 or included as a separate component downstream of the condenser 406. The partially dehydrated anode exhaust flow can be supplied from the condenser 406 to at least one hydrogen pump 408 through the anode exhaust conduit 308L.

[0036] In various embodiments, the partially hydrogenated anode exhaust stream supplied to at least one hydrogen pump 408 may contain at least about 40% mole fraction of H2O, e.g., 50-60% (e.g., ~56%) mole fraction of H2O, at least about 20% mole fraction of CO2, e.g., 25-35% (e.g., ~29%) mole fraction of CO2, at least about 10% mole fraction of H2, e.g., 10-20% (e.g., ~14%) mole fraction of H2, less than 1% mole fraction of CO, and less than 1% mole fraction of N2. Depending on the CO tolerance of at least one hydrogen pump 408, in some embodiments the mole fraction of CO in the anode exhaust stream may be between 0.5% and 1%. This may enable the WGS reactor 405 to operate at relatively high temperatures and allow for a larger thermal window of operation for the WGS reactor 405.

[0037] At least one hydrogen pump 408 may include one or more electrochemical hydrogen pumps. At least one electrochemical hydrogen pump 408 may include a hydrogen pump and a separator that electrochemically pumps pure hydrogen through a polymer membrane when an electric current or voltage is applied across the polymer membrane. In various embodiments, at least one electrochemical hydrogen pump 408 may include the high-pressure hydrogen separation and compression systems described in U.S. Patent No. 10,756,361 and / or No. 10,648,089, which are available from Skyre, Inc. under the name "H2RENEW®". At least one hydrogen pump 408 may include multiple pumps (e.g., multiple separation membrane stacks) connected in series and / or parallel, which can enable a higher overall hydrogen recovery rate and / or higher throughput. In some embodiments, at least one hydrogen pump 408 can withstand at least about 0.5% mole fraction of CO (including up to about 1% mole fraction of CO) in the dehydrated anode exhaust stream supplied to at least one hydrogen pump 408.

[0038] In one embodiment, at least one hydrogen pump 408 can recover more than 80% of the hydrogen in the dehydrated anode exhaust stream and discharge more than 99% pure compressed hydrogen product through the compressed hydrogen product conduit 410. For example, the compressed hydrogen product may be at least 99.99% pure (i.e., dry) hydrogen that can be pressurized to a pressure of 1 psig to 10,000 psig, such as 15 psig to 2,000 psig, e.g., 15 psig to 150 psig. In various embodiments, the compressed hydrogen product generated by at least one hydrogen pump 408 may be suitable for use or storage without additional mechanical compression or drying.

[0039] Referring again to Figure 2, the compressed hydrogen product in the compressed hydrogen product conduit 410 may be supplied to a splitter 411. The splitter 411 may be any other suitable fluid splitting device, such as a computer-controlled or operator-controlled valve, or a passive splitter including an opening or slit in the fluid conduit. The first portion of the compressed hydrogen product may be supplied from the splitter 403 to the hydrogen recycling conduit 412A for further use in the fuel cell system 10. The second portion of the compressed hydrogen product may be supplied from the splitter 403 to the hydrogen storage conduit 413 for storage and / or distribution or sale of the compressed hydrogen product. In some embodiments, the hydrogen storage conduit 413 may directly supply the compressed hydrogen product to one or more hydrogen storage containers 414 connected to the hydrogen storage conduit 413. Alternatively, one or more compressors (not shown in Figure 2) may be connected to the hydrogen storage conduit and configured to further compress the compressed hydrogen product to a pressure suitable for storage in one or more hydrogen storage containers 414.

[0040] In various embodiments, the hydrogen recycling conduit 412A can be used to supply compressed hydrogen products to one or more locations within the fuel cell system 10. In some embodiments, the hydrogen recycling conduit 412A can supply at least a portion of the compressed hydrogen products to a fuel source 400, which may be, for example, a natural gas source.

[0041] Alternatively or additionally, in some embodiments, at least a portion of the compressed hydrogen product can be supplied to the intake fuel flow of the fuel cell system 10. In some embodiments, the compressed hydrogen product may be supplied to the intake fuel downstream of one or more pretreatment units 400 (e.g., desulfurizers) of the fuel cell system 10. In one embodiment shown in Figure 2, the splitter 415 can direct at least a portion of the compressed hydrogen product from the hydrogen recycling conduit 412A to the hydrogen recycling conduit 412B, and the hydrogen recycling conduit 412B can supply at least a portion of the compressed hydrogen product to the fuel intake conduit 300A.

[0042] Alternatively or additionally, in some embodiments, at least a portion of the compressed hydrogen product can be supplied to one or more anode recycle loops of the hot box 100. In various embodiments, the compressed hydrogen product can be supplied to all anode recycle loops of the hot box 100 of the fuel cell system 10. In one embodiment shown in Figure 2, one or more splitters 416 can direct at least a portion of the compressed hydrogen product from hydrogen recycle conduit 412A to one or more hydrogen recycle conduits 412C. Each of the anode recycle conduits 412C can be fluidly connected to the anode recycle loop of its respective hot box 100. The compressed hydrogen product supplied to the anode recycle loops of the hot box 100 can mix with both the anode recycle fuel and new fuel in the anode recycle loop and enter the hot box 100 through the fuel conduit 300D.

[0043] In some embodiments, at least a portion of the compressed hydrogen product can also be supplied to the ATO 130 of one or more hot boxes 100 of the fuel cell system 10. In embodiments, the compressed hydrogen product can be supplied to the ATO 130 during the startup of the hot boxes 100 or other transient conditions and can be used for thermal management of the hot boxes 100. In embodiments shown in Figure 2, one or more hydrogen recycle conduits 412D can selectively redirect a portion of the compressed hydrogen product to the ATO 130 of one or more hot boxes 100. In some embodiments, the hydrogen recycle conduits 412D can be fluidly connected to anode exhaust conduits 308D for directing the compressed hydrogen product to their respective ATOs 130. By supplying hydrogen to the ATOs 130, the temperature of the hot boxes 100 is maintained at a substantially constant temperature, or as close to constant as is feasible or practical. Considering other variations (e.g., changes in ambient temperature, intentional changes in airflow), there is no predetermined flow rate control for the supply flow to the ATO130. In some configurations, the flow rate can be controlled to + / - 3 to 5% using a proportional solenoid valve. In other configurations, the flow rate can be controlled further (e.g., + / - 0.5%), but such other configurations are expensive.

[0044] In some embodiments, the compressed hydrogen product may be sufficiently pure (i.e., dry) to be reusable for use in the fuel cell system 10 without requiring additional processing or adjustment. Furthermore, in some embodiments, the dry compressed hydrogen product can be delivered to various components / locations of the fuel cell system 10 without the need for insulation, by tracing the conduits 412A, 412B, 412C, and 412D that carry the compressed hydrogen product to avoid water condensation. The dry compressed hydrogen product also does not risk condensation in undesirable locations in the fuel cell system 10, such as desulfurization tanks.

[0045] If the compressed hydrogen product is not sufficiently dry for use in the fuel cell system 10 or its components, a cooling condenser may optionally be used to further reduce the water content of the compressed hydrogen product before it is used in the fuel cell system 10.

[0046] In various embodiments, the system controller 225 (see Figure 1) can control the amount of compressed hydrogen product supplied to various locations within the fuel cell system 10 and / or to one or more hydrogen storage containers 414. In one non-limiting embodiment, during steady-state operation of the fuel cell system 10, all or almost all of the compressed hydrogen product can be supplied to the hot box 100 of the fuel cell system 10. Excess compressed hydrogen product not required for the operation of the fuel cell system 10 can be supplied to one or more hydrogen storage containers 414. The advantage of recirculating a large portion of the compressed hydrogen product into the fuel cell system 10 is that as more hydrogen product is recirculated as fuel, the need to meet precise and high fuel utilization targets for the fuel cell system 10 can be reduced. By supplying a relatively large amount of recirculated hydrogen product, the overall fuel utilization rate of the fuel cell system 10 can be kept high even with a lower utilization rate per pass. Furthermore, by lowering the fuel utilization rate of the fuel cell system 10 as desired, the amount of hydrogen product supplied to one or more hydrogen storage containers 414 can be increased.

[0047] Referring again to Figure 2, the unpumped effluent from at least one hydrogen pump 408 may mainly consist of water (e.g., water vapor and / or liquid water) and carbon dioxide. The unpumped effluent may also contain small amounts of hydrogen not separated from the anode exhaust, as well as smaller amounts of carbon monoxide, nitrogen, and other impurities. For example, the unpumped effluent may contain less than 10% mole fraction of H2, such as 0-5% mole fraction of H2, 0-1% mole fraction of CO, and 0-1% mole fraction of nitrogen. Liquid water can optionally be removed from at least one hydrogen pump 408 through a water discharge conduit 417, and the liquid water in the conduit 417 can optionally be purified and / or reused. Gaseous unpumped effluent from at least one hydrogen pump 408 may be supplied from at least one hydrogen pump 408 to the effluent conduit 418.

[0048] In some embodiments, the effluent from at least one hydrogen pump may optionally be supplied from the effluent conduit 418 to a blower 419, which may be any suitable fluid (e.g., gas) blower, pump, compressor, etc. The blower 419 can “pull” the unpumped effluent from at least one hydrogen pump 408. The blower 419 can further compress the effluent to a pressure between 2 and 15 psig, for example. The heat from compressing the unpumped effluent may raise the temperature of the unpumped effluent. This can preheat the effluent for subsequent catalytic or thermal reactions configured to oxidize some or all of the residual H2 and CO in the effluent. Compression of the effluent can also decouple the compression from subsequent CO2 compression, dewatering, and / or liquefaction processes that may be performed. In embodiments where the optional blower 419 is present, the compressed effluent from the blower 419 may be supplied to the effluent conduit 420. In some cases, it may be difficult to adjust (i.e., change the speed of) a large compressor with a high compression ratio. For example, a slight change in compressor speed can cause too much or too little gas to be drawn from the pipe, potentially leading to pressure turbulence upstream. However, small blowers have low gain, and slight speed adjustments will only slightly alter the flow rate and suction pressure. In some cases, a small storage volume downstream of the blower can be used to provide some capacitance to the system for pressure control. For example, the downstream storage volume might have a residence time of around one minute.

[0049] In various embodiments, the compressed effluent from the blower 419 may optionally be supplied to an oxidation reactor 421 through an effluent conduit 420. The oxidation reactor 421 may be a catalytic or thermal oxidation reactor, which may be configured to reduce or remove the remaining H2 and CO content from the effluent before a subsequent carbon dioxide treatment step. An oxygen source 422 may be connected to the oxidation reactor 421 and can supply oxygen for the oxidation reaction. In some embodiments, the oxygen source 422 may include an air blower. Alternatively or additionally, the oxygen source 422 may be an oxygen generator or oxygen storage device that can provide purified oxygen for the oxidation reaction. In embodiments where an optional oxidation reactor 421 is present, the effluent from the oxidation reactor 421 (which may consist almost entirely of H2O and CO2) may be supplied to an effluent conduit 423.

[0050] In some embodiments, the system 10 may optionally include a carbon dioxide treatment device 424 which can be operably connected to effluent conduits 418, 420, and / or 423 containing effluent products from at least one hydrogen pump 408. The carbon dioxide treatment device 424 may operate to compress and / or cool the effluent received from at least one hydrogen pump 408, which may optionally be compressed by a blower 419 and / or undergo an oxidation reaction in an oxidation reactor 421. The optional carbon dioxide treatment device 424 may be a condenser and / or dryer configured to remove water from the effluent. In some embodiments, the optional carbon dioxide treatment device 424 may also convert the effluent into liquefied CO2 products. The water removed from the effluent may optionally be removed from the carbon dioxide treatment device 424 through a water discharge conduit 425 for optional purification and / or reuse. The remaining portion of the spillway, which may contain purified or pure CO2, may be supplied through conduit 426 to one or more carbon dioxide storage containers 427 for CO2 storage and / or sequestration, or may be used for chemical processes, beverage carbonation, etc. In some embodiments, one or more carbon dioxide storage containers may include one or more cryogenic storage devices configured to convert CO2 into dry ice for storage.

[0051] Figure 3 schematically shows a fuel cell system 20 according to another embodiment of the present disclosure. The fuel cell system 20 of Figure 3 may be similar to the fuel cell system 10 described above with reference to Figure 2. Therefore, repeated descriptions of similar components are omitted for brevity. The fuel cell system 20 of Figure 3 may differ from the fuel cell system 10 of Figure 2 in that it can recover hydrogen products using lower pressure hydrogen pumps and higher pressure hydrogen pumps.

[0052] In particular, referring to Figure 3, a splitter 450 (e.g., a valve, a passive splitter, etc.) located within the anode exhaust conduit 308L can direct a portion of the partially hydrated anode exhaust flow to the anode exhaust conduit 451. The remaining portion of the partially hydrated anode exhaust flow in the anode exhaust conduit 308L can be supplied to at least one low-pressure hydrogen pump 452. At least one low-pressure hydrogen pump 452 may be configured to pump hydrogen separated from the anode exhaust flow to a relatively low pressure (e.g., 1 to 150 psig). In various embodiments, at least one low-pressure hydrogen pump 452 can pump hydrogen to a pressure suitable for use in the fuel cell system 20. The compressed hydrogen product from at least one low-pressure hydrogen pump 452 can be supplied to a hydrogen recycling conduit 412A for further use in the fuel cell system 20, as described above with reference to Figure 2. The remaining effluent from at least one low-pressure hydrogen pump 452 is fed into an effluent conduit 418 and can proceed to an optional blower 419, an optional oxidation reactor 421, and an optional carbon dioxide treatment device 424 for CO2 separation, as described above with reference to Figure 2. Liquid water from the effluent can optionally be recovered through a water discharge conduit 453.

[0053] Referring again to Figure 3, a portion of the partially hydrated anode exhaust flow located inside the anode exhaust conduit 451 may be supplied to at least one high-pressure hydrogen pump 454. At least one high-pressure hydrogen pump 454 may be configured to pump hydrogen separated from the anode exhaust flow to a relatively high pressure (e.g., 200 to 10,000 psig). In various embodiments, at least one high-pressure hydrogen pump 452 may pump hydrogen to a pressure suitable for hydrogen storage and / or commercial sale of purified hydrogen products. Compressed hydrogen products from at least one high-pressure hydrogen pump 454 may be supplied to one or more hydrogen storage containers 414 through a hydrogen product conduit 456. The remaining gaseous effluent from at least one high-pressure hydrogen pump 454 may be supplied to an effluent conduit 457, and liquid water from the effluent may optionally be recovered through a water discharge conduit 453. In some embodiments, the effluent conduit 457 can supply effluent from at least one high-pressure hydrogen pump 454 to an optional blower 419, an optional oxidation reactor 421, and an optional carbon dioxide treatment device 424 for separating CO2, as described above with reference to Figure 2.

[0054] In general, hydrogen products intended for storage and / or commercial sale may require higher pressures than hydrogen products recycled for use in the fuel cell system 20. In various embodiments, the compressed hydrogen products recovered from the anode exhaust of the fuel cell system 20 can be optimized for different applications by providing at least one low-pressure hydrogen pump 452 and at least one high-pressure hydrogen pump 454 capable of processing the anode exhaust flow in parallel. In some embodiments, one or more buffer tanks (not shown in Figure 3) may be provided upstream of at least one low-pressure hydrogen pump 452 and / or at least one high-pressure hydrogen pump 454 to mitigate fluctuations in the flow rates of the parallel anode exhaust flows feeding to each of the hydrogen pumps 452, 454.

[0055] Therefore, the fuel cell systems 10 and 20 shown in Figures 1-3 can use or recapture essentially all of the hydrogen and carbon content of the intake fuel supplied to the fuel cell systems 10 and 20. This increases the fuel utilization rate of the fuel cell systems 10 and 20.

[0056] Figure 4 schematically shows a fuel cell system 30 according to another embodiment of the present disclosure. The fuel cell system 30 of Figure 4 may be similar to the fuel cell systems 10 and 20 described above with reference to Figures 2 and 3. Therefore, repeated descriptions of similar components are omitted for brevity. The fuel cell system 30 of Figure 4 may differ from the fuel cell systems 10 and 20 of Figures 2 and 3 in that it can separate at least a portion of the CO2 from the anode exhaust flow using a carbon dioxide pump.

[0057] Referring to Figure 4, at least one carbon dioxide pump 600 may be located downstream of the water-gas shift (WGS) reactor 405 and condenser 406 in the anode exhaust flow from the hot box 100 of the fuel cell system 30. The condenser 406 may be configured to condense water vapor into liquid water and lower the temperature of the anode exhaust flow so that the temperature and / or water content of the anode exhaust flow are within the operating range of the carbon dioxide pump 600. The liquid water condensed from the anode exhaust flow can be removed through a water discharge conduit 407. The anode exhaust conduit 308L can supply the partially dehydrated anode exhaust flow from the condenser 406 to the inlet of at least one carbon dioxide pump 600.

[0058] At least one carbon dioxide pump 600 may include one or more electrochemical carbon dioxide pumps. At least one electrochemical carbon dioxide pump 600 may be configured to pump CO2 from a lower-pressure anode exhaust flow to a higher-pressure, nearly pure CO2 product, which may also contain water. In some embodiments, at least one electrochemical carbon dioxide pump may include a scrubber and a separator (i.e., a concentrator) which electrochemically pumps carbon dioxide through a polymer membrane when an electric current or voltage is applied across the polymer membrane. In various embodiments, at least one electrochemical carbon dioxide pump 600 may include the high-pressure carbon dioxide separation and compression system described in U.S. Patent Application Publication No. 2020 / 0222852, which is available from Skyre, Inc. under the name "CO2RENEW®". At least one carbon dioxide pump 600 may include multiple pumps (e.g., multiple separation membrane stacks) connected in series and / or parallel, enabling a higher overall recovery rate and / or higher throughput of CO2.

[0059] In one embodiment, at least one carbon dioxide pump 600 can recover at least 70%, for example 70-90% or more, of the CO2 present in the dehydrated anode exhaust stream. In some embodiments, at least one carbon dioxide pump 600 can pressurize the separated CO2 product to a pressure between 1 psig and 5,000 psig, such as 1-5 psig, 5-150 psig, or 150-5,000 psig. In some embodiments, the compressed CO2 product generated by at least one carbon dioxide pump 600 may be suitable for use, storage, or isolation without additional mechanical compression.

[0060] In some embodiments, compressed CO2 products from at least one carbon dioxide pump 600 may be supplied to a carbon dioxide processing apparatus 424 via a conduit 602. The carbon dioxide processing apparatus 424 can remove residual water from the compressed CO2 products by means of thermal swing adsorption (TSA) and / or pressure swing adsorption (PSA), etc. The water removed from the compressed CO2 products may optionally be removed via a water discharge conduit 425 for optional purification and / or reuse. The compressed CO2 products may optionally undergo further compression to pressurize the CO2 products to a pressure suitable for storage, use and / or sequestration. In some embodiments, the compressed CO2 products may be liquefied or solidified to form dry ice. Following processing by the carbon dioxide processing apparatus 424, the compressed CO2 products, which may contain purified or pure CO2, may be supplied to one or more carbon dioxide storage containers 427 via a conduit 426 for CO2 storage and / or sequestration, or may be used in chemical processes, drinking water carbonation, etc.

[0061] Referring again to Figure 4, the unpumped effluent from at least one carbon dioxide pump 600 may include hydrogen, water (e.g., steam and / or liquid water), carbon dioxide not separated from the anode exhaust by at least one carbon dioxide pump 600, and small amounts of carbon monoxide, nitrogen, and other impurities. In some embodiments, liquid water from the unpumped effluent can optionally be removed through a water discharge conduit 601. The remaining unpumped effluent from at least one carbon dioxide pump 600 may be supplied to a conduit 603 for recirculation to the fuel cell system 30.

[0062] In various embodiments, the unpumped spill from at least one carbon dioxide pump 600 may contain substantially all of the hydrogen and carbon monoxide from the anode exhaust flow. The concentrations of hydrogen and carbon monoxide in the unpumped spill flow are generally higher than those in the anode exhaust flow because most of the carbon dioxide and some of the water from the anode exhaust flow are removed by at least one carbon dioxide pump 600. This may favor the use of the spill flow in the conduit 603 in the fuel cell system 30, including use as a fuel source or auxiliary fuel for the stack 102 and / or ATO 130. In various embodiments, at least one blower 604 may be in fluid communication with the conduit 603. At least one blower 604 may include any suitable fluid (e.g., gas) blower, pump, compressor, etc. At least one blower 604 can compress the spill flow to a pressure suitable for use in the fuel cell system 10. In some embodiments, multiple blowers 604 may be used to compress portions of the spill flow to different pressures for different uses in the fuel cell system 10. For example, using a first blower 604 that is in fluid communication with the anode recycle conduit 412C, the pressure of the outflow material supplied to the anode recycle loop of the hot box 100 can be increased by 1 psi to 2 psi. At least a portion of the outflow supplied to the hot box 100 can also be supplied to the ATO 130 of the hot box 100 for thermal management and / or to remove nitrogen from the ATO 130. A proportional solenoid valve can be used to control a portion of the outflow supplied to the ATO 130 of each hot box 100. Using an additional blower 604 that is in fluid communication with the anode recycle conduit 412B, the pressure of the outflow material supplied to the fuel intake flow of the fuel cell system 30 can be increased by 10 psi to 15 psi.

[0063] In the fuel cell system 30 shown in Figure 4, almost all of the fuel can be recirculated as either separated carbon dioxide products or / or recirculated fuel for the fuel cell system 30, thus reducing the fuel utilization rate per pass of the fuel cell system 30. Furthermore, since residual CO2 in the outflow from at least one carbon dioxide pump 600 is recirculated back through the fuel cell system 30 and ultimately returned to the anode exhaust flow from the hot box 100, at least one carbon dioxide pump 600 does not need to have an extremely high CO2 recovery rate. In some embodiments, the CO2 recovery rate per pass of at least one carbon dioxide pump 600 may be between 70 and 90%. This enables nearly 100% overall CO2 recovery of the fuel cell system 30, minus the small amount of CO2 that is recirculated to the ATO 130 of the hot box 100 and / or may be generated thereby.

[0064] Depending on the CO tolerance of at least one carbon dioxide pump 600, in some embodiments the WGS reactor 405 and the anode exhaust adjustment unit 404 can be removed from the fuel cell system 30 in Figure 4. Thus, the anode exhaust from the manifold 104 can be supplied to a condenser 406 which can be configured to adjust the anode exhaust flow so that the temperature and / or water content of the anode exhaust flow is within the operating range of at least one carbon dioxide pump 600. In such cases, the anode exhaust flow entering at least one carbon dioxide pump 600, as well as the outflow flow from at least one carbon dioxide pump 600, may have relatively high concentrations of H2 and CO.

[0065] Figure 5 schematically shows a fuel cell system 40 according to another embodiment of the present disclosure. The fuel cell system 40 of Figure 5 may be similar to the fuel cell system 30 described above with reference to Figure 4. Therefore, repeated descriptions of similar components are omitted for brevity. The fuel cell system 40 of Figure 5 may differ from the fuel cell system 30 of Figure 4 by adding at least one hydrogen pump 408 upstream of at least one carbon dioxide pump 600. In various embodiments, the anode exhaust flow may be supplied from the condenser 406 through the anode exhaust conduit 308L to at least one hydrogen pump 408. The at least one hydrogen pump 408 may generate compressed hydrogen products as described above, which may be supplied to the conduit 410. The compressed hydrogen products from the at least one hydrogen pump 408 may be recirculated to the fuel cell system 30 and / or supplied to one or more hydrogen storage containers 414 for storage and potential commercial sale. In the embodiment shown in Figure 5, a splitter 413 can be used to supply a portion of the compressed hydrogen product to one or more hydrogen storage containers 414 through a hydrogen storage conduit 413, and the remaining portion of the compressed hydrogen product can be recycled through a conduit 412A for use in a fuel cell system.

[0066] The unpumped effluent from at least one hydrogen pump 408 may contain mainly water (e.g., water vapor and / or liquid water) and carbon dioxide, along with small amounts of hydrogen, carbon monoxide, nitrogen, and other impurities. The liquid water from the unpumped effluent can optionally be removed through the water discharge conduit 417. The remaining effluent can be supplied to at least one carbon dioxide pump 600 through conduit 308M. At least one carbon dioxide pump 600 can separate the majority of CO2 (e.g., 70% or more) from the effluent and supply compressed CO2 products, as described above with reference to Figure 4. The compressed CO2 products can optionally be supplied to the carbon dioxide treatment device 424 through conduit 602.

[0067] The unpumped effluent from at least one carbon dioxide pump 600 may contain water (e.g., water vapor and / or liquid water) and carbon dioxide not separated by at least one carbon dioxide pump 600, as well as small amounts of hydrogen, carbon monoxide, nitrogen, and other impurities. The liquid water from the unpumped effluent can optionally be removed through the water discharge conduit 601. The remaining effluent can be fed into the conduit 603 and recycled for use in the fuel cell system 40 as described above.

[0068] An advantage of providing at least one hydrogen pump 408 upstream of at least one carbon dioxide pump 600 is that at least one hydrogen pump 408 can reduce the gas flow rate of the process flow before it is supplied to at least one carbon dioxide pump 600. Furthermore, by removing hydrogen using at least one hydrogen pump 408, the concentration of CO2 in the process flow supplied to at least one carbon dioxide pump 600 can be increased. The system 40 in Figure 5 can also generate a pure or purified hydrogen product, which can be stored for later use and / or sale.

[0069] Figure 6 schematically shows a fuel cell system 50 according to another embodiment of the present disclosure. The fuel cell system 50 in Figure 5 may be similar to the fuel cell system 10 described above with reference to Figure 2. Therefore, repeated descriptions of similar components are omitted for brevity. The fuel cell system 50 in Figure 3 may differ from the fuel cell system 10 in Figure 2 by adding at least one carbon dioxide pump 600 upstream of at least one hydrogen pump 408. In various embodiments, the anode exhaust flow may be supplied from the condenser 406 to at least one carbon dioxide pump 600 through the anode exhaust conduit 308L. The at least one carbon dioxide pump 600 can separate most of the CO2 (e.g., 70% or more) from the anode exhaust flow and provide compressed CO2 products, as described above with reference to Figure 4. The compressed CO2 products may optionally be supplied to a carbon dioxide treatment device 424 through the conduit 602.

[0070] The unpumped effluent from at least one carbon dioxide pump 600 may include a hydrogen enrichment process flow containing water (e.g., steam and / or liquid water), hydrogen, and carbon dioxide not separated by at least one carbon dioxide pump 600, as well as small amounts of carbon monoxide, nitrogen, and other impurities. Liquid water from the unpumped effluent can optionally be removed through a water discharge conduit 601. The remaining effluent can be supplied to at least one hydrogen pump 408 through a conduit 604.

[0071] At least one hydrogen pump 408 can generate compressed hydrogen products as described above, which can be supplied to the conduit 410. The compressed hydrogen products from at least one hydrogen pump 408 can be recirculated to the fuel cell system 30 and / or supplied to one or more hydrogen storage containers 414 for storage and potential commercial sale. In the embodiment shown in Figure 6, a splitter 411 can be used to supply a portion of the compressed hydrogen products to one or more hydrogen storage containers 414 through the hydrogen storage conduit 413, and the remainder of the compressed hydrogen products can be recirculated through the conduit 412A for use in the fuel cell system.

[0072] The gaseous, unpumped effluent from at least one hydrogen pump 408 may be supplied from at least one hydrogen pump 408 to an effluent conduit 418, which may optionally be supplied to a blower 419 and an oxidation reactor 421 configured to reduce or remove residual H2 and CO from the effluent, as previously described with reference to Figure 2. The remaining effluent may mainly consist of water and CO2, which may be supplied through conduit 606 to a carbon dioxide treatment device 424 for recovery, storage and / or use of the remaining CO2, as described above.

[0073] The foregoing description of the disclosed embodiments is provided to enable those skilled in the art to make or use the disclosure. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other embodiments without departing from the scope of the disclosure. Accordingly, the disclosure is not intended to be limited to the embodiments shown herein, but should be given the broadest scope consistent with the principles and novel features disclosed herein.

Claims

1. at least one hot box including a fuel cell stack configured to generate an anode exhaust product; at least one hydrogen pump configured to use the anode exhaust product to produce a compressed hydrogen product and an unpumped effluent product; an oxidation reactor configured to reduce or remove residual H2 and CO from said unpumped effluent product; at least one product conduit fluidly connecting an anode exhaust product outlet of said hot box to an inlet of said at least one hydrogen pump; a compressed hydrogen product conduit connected to the compressed hydrogen product outlet of the at least one hydrogen pump; and a fuel cell system comprising at least one effluent conduit fluidly connecting an unpumped effluent outlet of said at least one hydrogen pump to said oxidation reactor;

2. 10. The fuel cell system of claim 1, further comprising: a plurality of hot boxes each containing a fuel cell stack and generating an anode exhaust product; at least one product conduit fluidly connecting an anode exhaust product outlet of each of the plurality of hot boxes to a manifold; and at least one product conduit fluidly connecting an outlet of the manifold to the inlet of the at least one hydrogen pump.

3. 3. The fuel cell system of claim 2, wherein each hot box of the plurality of hot boxes includes a first anode exhaust outlet fluidly connected to the manifold by at least one product conduit, and a second anode exhaust outlet fluidly connected to the manifold by at least one product conduit.

4. the anode exhaust products discharged from each of the hot boxes through the first anode exhaust outlet include anode exhaust that has passed through an anode exhaust cooler of each of the hot boxes; 4. The fuel cell system of claim 3, wherein the anode exhaust products discharged from each of the hot boxes through the second anode exhaust outlet include anode exhaust that bypasses the anode exhaust cooler of each of the hot boxes.

5. A method for producing a water-gas shift reactor, further comprising: at least one product conduit fluidly connects an outlet of the manifold to an inlet of the water-gas shift reactor; at least one product conduit fluidly connects the outlet of the water-gas shift reactor to the inlet of the condenser; 4. The fuel cell system of claim 3, wherein at least one product conduit fluidly connects an outlet of the condenser to the inlet of the at least one hydrogen pump.

6. 3. The fuel cell system of claim 2, wherein the at least one hydrogen pump comprises an electrochemical hydrogen pump that produces a compressed hydrogen product containing greater than 99 percent hydrogen by volume.

7. 7. The fuel cell system of claim 6, wherein the compressed hydrogen product conduit is fluidly connected to at least one hydrogen recycle conduit configured to recirculate at least a portion of the compressed hydrogen product for use by the fuel cell system.

8. 8. The fuel cell system of claim 7, wherein the compressed hydrogen product conduit is fluidly connected to at least one hydrogen recycle conduit that is fluidly connected to an anode recycle loop of a hot box of the fuel cell system.

9. 8. The fuel cell system of claim 7, wherein the compressed hydrogen product conduit is fluidly connected to at least one hydrogen recycle conduit that is fluidly connected to an anode tail gas oxidizer of a hot box of the fuel cell system.

10. 8. The fuel cell system of claim 7, wherein the compressed hydrogen product conduit is fluidly connected to at least one hydrogen recycle conduit that is fluidly connected to at least one of a fuel source of the fuel cell system and a fuel intake conduit to one or more hot boxes of the fuel cell system.

11. 8. The fuel cell system of claim 7, wherein the at least one hydrogen recycle conduit is configured to recirculate a first portion of the compressed hydrogen product for use by the fuel cell system, and the compressed hydrogen product conduit is fluidly connected to at least one hydrogen storage conduit configured to supply a second portion of the compressed hydrogen product to one or more hydrogen storage vessels.

12. The fuel cell system of claim 1, further comprising a blower configured to compress an unpumped effluent product from the unpumped effluent outlet of the at least one hydrogen pump and fluidly connected to the at least one effluent conduit.

13. An anode tail gas oxidizer (ATO) disposed within the at least one hot box of the fuel cell system; The fuel cell system of claim 1 , wherein the oxidation reactor is located outside the at least one hot box.

14. The method of claim 13, further comprising: a carbon dioxide treatment device fluidly connected to an outlet of the oxidation reactor by at least one effluent conduit; 10. The fuel cell system of claim 1, wherein the carbon dioxide treatment device is configured to convert the unpumped effluent product into a purified or pure CO2 product.

15. The fuel cell system of claim 1 , wherein the fuel cell system comprises a solid oxide fuel cell system.

16. further comprising at least one carbon dioxide pump; (a) an inlet of the at least one carbon dioxide pump is fluidly connected to the unpumped effluent outlet of the at least one hydrogen pump by at least one unpumped effluent conduit, a compressed carbon dioxide product conduit is connected to the compressed carbon dioxide product outlet of the at least one carbon dioxide pump, and at least one unpumped effluent recycle conduit is connected to the unpumped effluent outlet of the at least one carbon dioxide pump for recirculating unpumped effluent from the at least one carbon dioxide pump for use in the fuel cell system; Or, (b) at least one product conduit fluidly connects the anode exhaust product outlet of the hot box to the inlet of the at least one carbon dioxide pump, a compressed carbon dioxide product conduit is connected to the compressed carbon dioxide product outlet of the at least one carbon dioxide pump, and at least one unpumped effluent recycle conduit is connected to the unpumped effluent outlet of the at least one carbon dioxide pump for supplying unpumped effluent from the at least one carbon dioxide pump to the inlet of the at least one hydrogen pump; The fuel cell system according to claim 1 .

17. At least one hot box including a fuel cell stack configured to generate an anode exhaust product; a lower pressure hydrogen pump, at least one product conduit fluidly connected to an inlet of the lower pressure hydrogen pump for receiving a first portion of the anode exhaust product, wherein compressed hydrogen product produced by the lower pressure hydrogen pump is recycled for use in the fuel cell system; a higher pressure hydrogen pump, at least one product conduit fluidly connected to an inlet of the higher pressure hydrogen pump for receiving a second portion of the anode exhaust product, and wherein the compressed hydrogen product produced by the higher pressure hydrogen pump is supplied to one or more hydrogen storage vessels; at least one hydrogen pump configured to use the anode exhaust product to produce a compressed hydrogen product and an unpumped effluent product; an oxidation reactor configured to reduce or remove residual H2 and CO from said unpumped effluent product; at least one product conduit fluidly connecting an anode exhaust product outlet of said hot box to an inlet of said at least one hydrogen pump; a compressed hydrogen product conduit connected to the compressed hydrogen product outlet of the at least one hydrogen pump; and a fuel cell system comprising at least one effluent conduit fluidly connecting an unpumped effluent outlet of said at least one hydrogen pump to said oxidation reactor; 18. At least one hot box including a fuel cell stack configured to generate an anode exhaust product; at least one carbon dioxide pump configured to remove at least about 70% of the carbon dioxide from the anode exhaust product to produce a compressed carbon dioxide product and an unpumped effluent product; an oxidation reactor located outside of the at least one hot box and configured to reduce or remove residual H2 and CO from the unpumped effluent product; at least one product conduit fluidly connecting an anode exhaust product outlet of the hot box to an inlet of the at least one carbon dioxide pump; a compressed carbon dioxide product conduit connected to the compressed carbon dioxide product outlet of the at least one carbon dioxide pump; and a fuel cell system comprising at least one effluent conduit fluidly connecting an unpumped effluent outlet of said at least one carbon dioxide pump to said oxidation reactor;

19. 1. A method of operating a fuel cell system, comprising: providing a fuel inlet flow to at least one hot box of the fuel cell system; generating an anode exhaust product stream from the at least one hot box of the fuel cell system; supplying the anode exhaust product stream to at least one hydrogen pump; producing a compressed hydrogen product and an unpumped effluent in said at least one hydrogen pump; recycling at least a portion of the compressed hydrogen product to the at least one hot box of the fuel cell system; and feeding the unpumped effluent to an oxidation reactor and reducing or removing residual H2 from the unpumped effluent product compressed by a blower; A method comprising:

20. The oxidation reactor is disposed outside the at least one hot box; and extracting purified or pure CO from the unpumped effluent from the at least one hydrogen pump. ２ generating a product; and providing a portion of the compressed hydrogen product to at least one hydrogen storage vessel.

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