Fuel cell systems and methods with improved fuel utilization
Patent Information
- Authority / Receiving Office
- TW · TW
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2022-10-25
- Publication Date
- 2023-09-16
Smart Images
Figure TWG2TA000924725_001 
Figure TWG2TA000924725_002 
Figure TWG2TA000924725_003
Abstract
Description
[Technical Field]
[0001] The present invention relates to a fuel cell system and a method for operating a fuel cell system. [Previous Technology]
[0002] For example, fuel cell systems such as solid oxide fuel cells are electrochemical devices that can efficiently convert the energy stored in fuel into electrical energy. High-temperature fuel cells include solid oxide and molten carbonate fuel cells. These fuel cells can operate using hydrogen and / or hydrocarbon fuels. Various fuel cells exist, such as solid oxide regenerative fuel cells, which also allow reverse operation, so that oxidized fuel can be reduced to unoxidized fuel using electrical energy as input. [Summary of the Invention]
[0003] One embodiment of the fuel cell system includes: at least one heatbox including a fuel cell stack and generating anode exhaust products; at least one hydrogen pump; at least one product conduit fluidly connecting the anode exhaust product outlet of the heatbox to the inlet of the 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 at least one effluent conduit connected to the unpumped effluent outlet of the at least one hydrogen pump.
[0004] Another embodiment of the fuel cell system includes: at least one heatbox including a fuel cell stack and generating anode exhaust products; at least one carbon dioxide pump; at least one product conduit fluidly connecting the anode exhaust product outlet of the heatbox 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 effluent conduit connected to the unpumped effluent outlet of the at least one carbon dioxide pump.
[0005] Another embodiment includes a method of operating a fuel cell system, the method comprising: providing a fuel inlet flow to at least one heatbox of the fuel cell system; generating an anode exhaust product flow from the at least one heatbox of the fuel cell system; providing 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 recycling at least a portion of the compressed hydrogen products to the at least one heatbox of the fuel cell system.
[0006] Another embodiment includes a method of operating a fuel cell system, the method comprising: providing a fuel inlet 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; providing the anode exhaust product flow to at least one carbon dioxide pump; generating compressed carbon dioxide product and unpumped effluent in the at least one carbon dioxide pump; and recycling 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.
Implementation Method
[0014] Various embodiments are described in detail with reference to the accompanying drawings. Where 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 and are not intended to limit the scope of the invention or the claims.
[0015] Figure 1 is a schematic diagram of a heat box 100 of a fuel cell system 10 (e.g., a solid oxide fuel cell (SOFC) system) according to various embodiments of the present invention. The heat box 100 may contain a fuel cell stack 102, such as a solid oxide fuel cell stack (wherein one of the stacked solid oxide fuel cells contains a ceramic electrolyte, such as yttrium-stabilized zirconium oxide (YSZ) or scandium oxide-stabilized zirconium oxide (SSZ); an anode, such as nickel-YSZ or Ni-SSZ cermet; and a cathode electrode, such as strontium lanthanum manganese oxide (LSM)). The stack 102 may be arranged in multiple columns stacked on top of each other.
[0016] The heat exchanger 100 may also include an anode reflux heat exchanger 110, a cathode reflux heat exchanger 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 lines 300D, 302A, 304C, 306, and 308G, as well as other components of the fuel cell system 10 that may be located outside or partially outside the heat exchanger 102. However, the invention is not limited to any particular location of the components relative to the heat exchanger 102.
[0017] The fuel stream may enter the heat box 102 and flow to the anode recirculation heat exchanger 110 via fuel conduit 300D. The fuel stream may include a mixture of hydrocarbon fuel (e.g., natural gas), recirculated anode exhaust from the fuel cell system 10, and, where applicable, recirculated hydrogen products, as described in further detail below. The fuel stream may be heated in the anode recirculation heat exchanger 110 and may flow from the anode recirculation heat exchanger 110 to the stack 102 via fuel conduit 300E.
[0018] The system blower 208 can be configured to provide airflow (e.g., inlet flow) to the anode exhaust cooler 140 via air duct 302A. Air flows from the anode exhaust cooler 140 to the cathode return heat exchanger via air duct 302B. Air flows from the cathode return heat exchanger 120 to the stack 102 via air duct 302C.
[0019] Anode exhaust generated in stack 102 is supplied to anode reflux heat exchanger 110 via anode exhaust duct 308A. Anode exhaust may contain unreacted fuel and may also be referred to herein as fuel exhaust. The anode exhaust located within anode reflux heat exchanger 110 transfers heat to the incoming fuel flow flowing through anode reflux heat exchanger 110 to stack 102. Anode exhaust can be supplied from anode reflux heat exchanger 110 to anode exhaust duct 308B. Anode exhaust can flow through anode exhaust duct 308B to anode exhaust cooler 140. Anode exhaust from anode exhaust cooler 140 can exit heatbox 100 via anode exhaust duct 308C. An anode recirculation blower (not shown in Figure 1) is in fluid communication with anode exhaust duct 308C and can be configured to move anode exhaust through anode exhaust duct 308C, as discussed in further detail below. In some embodiments, separator 511 may be configured to selectively supply a portion of the anode exhaust gas exiting anode exhaust conduit 308C to anode exhaust conduit 308D. Separator 511 may be, for example, a computer-controlled or operator-controlled valve or any other suitable fluid separation device, such as a passive separator containing openings or gaps in the fluid conduit. Anode exhaust conduit 308D may, for example, during startup or other transient operating states of the SOFC system 10, selectively redirect a portion of the anode exhaust gas exiting anode exhaust cooler 140 to ATO 130 via anode exhaust conduit 308D.
[0020] In the embodiment shown in FIG1, all anode exhaust in the heat box 100 passes through the anode exhaust cooler 140 before leaving the heat box 100 via the anode exhaust conduit 308C. In other embodiments, as described in further detail below, at least a portion of the anode exhaust may leave the heat box 100 before passing through the anode exhaust cooler 140. For example, a portion of the anode exhaust flow may leave the heat box 100 via an anode exhaust conduit (not shown in FIG1), which may be located between the anode reflux heat exchanger 110 and the anode exhaust cooler 140.
[0021] The cathode exhaust generated in stack 102 flows to ATO 130 via exhaust pipe 304A. A vortex generator 550 can be housed in exhaust pipe 304A and configured to vortex the cathode exhaust. Anode exhaust pipe 308D can be fluidly connected downstream of the vortex generator 550 to either cathode exhaust pipe 304A or ATO 130. The vortexed cathode exhaust can be mixed with the anode exhaust from anode exhaust pipe 308D and then supplied to ATO 130. The mixture can be oxidized in ATO 130 to produce ATO exhaust. ATO exhaust flows from ATO 130 to cathode return heat exchanger 120 via exhaust pipe 304B. ATO exhaust flows from cathode return heat exchanger and exits heat box 100 via exhaust pipe 304C.
[0022] Water flows from a water source 206, such as a water tank or pipe, through water pipe 306 to steam generator 160. Steam generator 160 sprays water into anode exhaust pipe 308B. Heat from the anode exhaust supplied to exhaust pipe 308B from anode reflux heat exchanger 110 vaporizes the water to generate steam. Steam mixes with anode exhaust to provide a humidified anode exhaust flow, which flows from anode exhaust pipe 308B through anode exhaust cooler 140 and into anode exhaust pipe 308C.
[0023] System 10 may further include a system controller 225 configured to control various components of system 10. Controller 225 may include a central processing unit configured to execute stored instructions. For example, controller 225 may be configured to control the flow of fuel and / or air through system 10 based on fuel composition data. System 10 may also include one or more fuel reforming catalysts 112, 114, and 116.
[0024] During operation, stack 102 uses the supplied fuel and air to generate electricity and produces anode exhaust (i.e., fuel exhaust) and cathode exhaust (i.e., air exhaust). Anode exhaust may contain hydrogen, water vapor, carbon monoxide, carbon dioxide, some unreacted hydrocarbon fuels (such as methane), and other reaction byproducts and impurities.
[0025] FIG2 is a schematic diagram of the components of a fuel cell system 10 according to an embodiment of the present invention. The fuel cell system 10 may include at least one heat box 100, such as the heat box 100 described above with reference to FIG1. For example, the fuel cell system 10 may include n heat boxes 100, where n is an integer between 1 and 100, such as 2 to 10, such as 4 to 8. The fuel cell system 10 shown in FIG2 includes two heat boxes 100, but fuel cell systems according to various embodiments may include more or fewer heat boxes 100.
[0026] Figure 2 schematically illustrates the flow of fuel and anode exhaust through a fuel cell system 10 according to an embodiment of the present invention. Referring to Figure 2, system 10 may be coupled to a fuel source 400, which may supply suitable fuel to fuel cell system 10. Fuel source 400 may include one or more fuel storage containers (e.g., fuel tanks or similar containers) that may be located in the same location as system 10. Alternatively, fuel source 400 may supply fuel to system 10 from a remote source (e.g., on a gas utility line). Fuel supplied to fuel cell system 10 from fuel source 400 may include any suitable hydrocarbon fuel, including (but not limited to) methane, natural gas containing methane and hydrogen and other gases, propane or other biogas, or carbon fuels (e.g., carbon monoxide), oxygenated carbon gases (e.g., methanol), or mixtures containing other carbon gases and hydrogen gases (e.g., water vapor, H2 gas, or mixtures thereof). For example, the mixture may contain syngas derived from coal or natural gas reforming.
[0027] In some embodiments, fuel from fuel source 400 may undergo one or more pretreatment steps before being supplied to the heat box 100 of fuel cell system 10. For example, fuel inlet pipe 300A coupled to fuel source 400 may supply fuel to one or more pretreatment units 402, such as one or more desulfurizers, to remove sulfur and / or other undesirable impurities from the fuel stream. The pretreated fuel may then flow through fuel pipe 300B to each of the heat boxes 100.
[0028] In some embodiments, each heat chamber 100 may additionally include a catalytic partial oxidation (CPOx) reactor 200, a mixer 210, a CPOx blower 204 (e.g., an air blower), and an anode recirculation blower 212, which may be located outside the heat chamber 100. However, the invention is not limited to any particular position of the components relative to the heat chamber 100.
[0029] Referring again to Figure 2, each CPOx reactor 200 associated with the corresponding hot box 100 can receive an inlet fuel flow through fuel line 300B. A CPOx blower 204 can supply air to the CPOx reactor 204. Fuel and / or air from the CPOx reactor 200 can be supplied to mixer 210 through fuel line 300C. Mixer 210 can be configured to mix the fuel flow with the recirculated anode exhaust from hot box 100. This mixture of fresh fuel and recirculated anode exhaust can then be supplied to hot box 100 through fuel line 300D, as described above with reference to Figure 1.
[0030] Anode exhaust (i.e., fuel exhaust) from each heatbox 100 may exit the heatbox 100 via anode exhaust conduit 308C, as discussed above with reference to Figure 1. Separator 511 (see Figure 1) may selectively redirect a portion of the anode exhaust located in anode exhaust conduit 308C to the heatbox 100 via anode exhaust conduit 308D. As previously discussed, during startup or other transient operating conditions, a portion of the anode exhaust redirected via anode exhaust conduit 308D may be supplied to the ATO 130 of the heatbox 100.
[0031] In the embodiment shown in Figure 2, residual anode exhaust gas located in anode exhaust duct 308C can be supplied to separator 403. Separator 403 can be, for example, a computer-controlled or operator-controlled valve or any other suitable fluid separation device, such as a passive separator containing openings or gaps in the fluid duct. A first portion of the anode exhaust gas can be supplied from separator 403 to anode recirculation blower 212 via anode exhaust duct 308E. Anode recirculation blower 212 can be any suitable fluid (e.g., gas) blower, pump, compressor, etc. A first portion of the anode exhaust gas can be supplied from anode recirculation blower 212 to mixer 210 via anode exhaust duct 308F. As discussed above, the recirculated anode exhaust gas can be mixed with fresh fuel in mixer 210 before re-entering the hot box 100 via fuel duct 300D. As used herein, the portion of the anode exhaust that leaves the heatbox 100 via the anode exhaust pipe 308C, is recirculated by the anode recirculation blower 212 to mix with fresh fuel in the mixer 210, and re-enters the heatbox 100 via the fuel pipe 300D can be referred to as "anode recirculation". The fluid path of the anode that is recirculated between the anode exhaust pipe 308C at the outlet of the heatbox 100 and the fuel pipe 300D at the inlet of the heatbox 100 can be referred to as "anode recirculation loop".
[0032] A second portion of the anode exhaust can be provided to manifold 104 via anode exhaust conduit 308G from separator 403. Manifold 104 can be connected to a plurality of heatboxes 100 of system 10 via corresponding anode exhaust conduit 308G, and in some embodiments includes connections to all heatboxes 100 of system 10. Alternatively, system 10 may include a plurality of manifolds 104, wherein each manifold 104 can be connected to a subset of heatboxes 100 of system 10. In various embodiments, anode exhaust flows from the plurality of heatboxes 100 of system 10 can be combined in manifold 104.
[0033] Referring again to FIG. 2, in some embodiments, each of the heatboxes 100 may include an additional anode exhaust conduit 308H, which is fluidly connected to the manifold 104 as appropriate. In some embodiments, the additional anode exhaust conduit 308H, as appropriate, provides a direct fluid path between the heatbox 100 and the manifold 104. In some embodiments, the anode exhaust within the anode exhaust conduit 308H, as appropriate, may exit the heatbox 100 upstream of the anode exhaust cooler 104 (see FIG. 1). For example, the heatbox 100 may include a separator (e.g., a valve, a passive separator, etc.) within the anode fluid conduit 308B located between the anode reflux heat exchanger 110 and the anode exhaust cooler 140 in the heatbox 100 shown in FIG. 1. The separator may divert a portion of the anode exhaust flow from the anode exhaust conduit 308B to the anode exhaust conduit 308H, as appropriate, so that this portion of the anode exhaust flow can be directly supplied to the manifold 104 shown in FIG. 2. As described above, the remainder of the anode exhaust flow can continue through the anode exhaust cooler 140 and into the anode exhaust duct 308C.
[0034] Therefore, in some embodiments, the anode exhaust provided to manifold 104 may include a first portion of the anode exhaust that exits the heat box 100 at the outlet of the anode exhaust cooler 140 and flows through anode exhaust conduit 308C, separator 511 and / or 403, and anode exhaust conduit 308G to manifold 104; and a second portion of the anode exhaust that exits the heat box 100 upstream of the anode exhaust cooler 140 and flows through anode exhaust conduit 308H to manifold 104. Thus, the second portion of the anode exhaust may bypass the anode exhaust cooler 140 and therefore may have a higher temperature than the first portion of the anode exhaust flowing through the anode exhaust cooler 140.
[0035] In some embodiments, the mixture of anode exhaust gas received in manifold 104 may be variable, such that during a certain period of time, a larger portion (including all anode exhaust gas) of the anode exhaust gas supplied to manifold 104 from one or more heat boxes 100 may be a first portion of the anode exhaust gas supplied via anode exhaust conduit 308G (i.e., the anode exhaust gas that has passed through the anode exhaust gas cooler 140 of heat box 100), and at other times, a larger portion (including all anode exhaust gas) of the anode exhaust gas supplied to manifold 104 from one or more heat boxes 100 may be a second portion of the anode exhaust gas supplied via anode exhaust conduit 308H (i.e., the anode exhaust gas that has bypassed the anode exhaust gas cooler 140 of heat box 100). The system controller 225 described above with reference to FIG. 1 may be used to control the mixture of the first and second portions of the anode exhaust gas supplied to manifold 104 from each of the heat boxes 100.
[0036] In some embodiments, the first portion of the anode exhaust supplied to the manifold 104 via 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 about 100°C and 180°C, and the second portion of the anode exhaust supplied to the manifold 104 via 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 about 300°C and 500°C.
[0037] Therefore, by providing an anode exhaust stream comprising a mixture of a low-temperature first portion of the anode exhaust passing through the anode exhaust cooler 140 of the hot box 100 and a low-temperature second portion of the anode exhaust bypassing the anode exhaust cooler 140, the temperature of the anode exhaust in the manifold 104 can be controlled to vary. In some embodiments, the temperature of the anode exhaust in the manifold 104 can be controlled to include more heat than is required for subsequent H2 recovery and / or CO2 separation processes, as described in further detail below. Providing an anode exhaust stream containing excess heat offers the advantage that, if cooling of the anode exhaust is required in one or more subsequent processes, the parasitic power consumed is less than the power required to heat the anode exhaust for such similar processes.
[0038] Referring again to FIG. 2, a combined anode exhaust stream from multiple heatboxes 100 can be provided from manifold 104 to anode exhaust regulating unit 404 via anode exhaust conduit 308I. Anode exhaust regulating unit 404 can be configured to modify the temperature of the anode exhaust stream so that the anode exhaust stream is suitable for introduction into water-gas shift (WGS) reactor 405 located downstream of anode exhaust regulating unit 404. Anode exhaust regulating 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 scope of the present invention. In some embodiments, when the temperature of the anode exhaust stream is greater than the operating temperature range of the WGS reactor, one or more heat transfer devices may be cooled by a cooling medium (e.g., cooling water and / or air) to reduce the temperature of the anode exhaust stream flowing through anode exhaust regulating unit 404. In other embodiments, when the temperature of the anode exhaust stream is below the operating temperature range of the WGS reactor 405, one or more heat transfer devices may transfer heat to the anode exhaust stream to increase the temperature of the anode exhaust stream flowing through the anode exhaust regulating unit 404. Heat transfer to the anode exhaust stream can be achieved by heat exchange with a fluid medium (e.g., combustion gas) having a higher temperature than the anode exhaust stream, or by directly heating the anode exhaust stream using a heater (e.g., an electric heater). In various embodiments, the temperature of the anode exhaust exiting the anode exhaust regulating unit 404 can be between approximately 150°C and 300°C, for example, between approximately 200°C and 250°C.
[0039] Referring again to Figure 2, the anode exhaust stream can be supplied from the anode exhaust regulating unit 404 to the WGS reactor 405 via the anode exhaust pipe 308J. The WGS reactor 405 can be configured to use a water-gas shift reaction to convert CO and H2O in the anode exhaust into CO2 and H2. In various embodiments, the WGS reactor 405 can be a low-temperature WGS reactor 405 and can have a nominal operating temperature between approximately 200°C and 250°C. After the water-gas shift reaction, the anode exhaust stream can mainly consist of H2O, CO2, and H2, and smaller amounts of CO, N2, and other impurities.
[0040] The anode exhaust stream can then be supplied from the WGS reactor 405 to the condenser 406 via anode exhaust conduit 308K. The condenser 406 can be cooled by a cooling medium (e.g., cooling water and / or air) to condense water vapor into liquid water and reduce the temperature of the anode exhaust stream to below 100°C, for example, between 50°C and 80°C (e.g., about 70°C). The liquid water can be removed from the condenser 406 via a water discharge conduit 407, and the liquid water in conduit 407 can be purified and / or reused as appropriate. In various embodiments, a water eliminator can be integrated into the design of the condenser 406 or included as a separate component downstream of the condenser 406. A partially dehydrated anode exhaust stream can be supplied from the condenser 406 to at least one hydrogen pump 408 via anode exhaust conduit 308L.
[0041] In various embodiments, the partial hydrogenated anode exhaust stream provided to at least one hydrogen pump 408 may include at least about 40% molar fraction of H₂O, for example 50-60% (e.g., about 56%) molar fraction of H₂O, at least about 20% molar fraction of CO₂, for example 25-35% (e.g., about 29%) molar fraction of CO₂, at least about 10% molar fraction of H₂, for example 10-20% (e.g., about 14%) molar fraction of H₂, less than 1% molar fraction of CO, and less than 1% molar fraction of N₂. Depending on the CO tolerance of the at least one hydrogen pump 408, in some embodiments, the molar fraction of CO in the anode exhaust stream may be between 0.5% and 1%. This allows for relatively high temperature operation of the WGS reactor 405 and allows the WGS reactor 405 to have a larger thermal operating window.
[0042] 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 separator that electrochemically pumps pure hydrogen through the polymer membrane when a current or voltage is applied across the membrane. In various embodiments, at least one electrochemical hydrogen pump 408 may include a high-pressure hydrogen separation and compression system, which is available from Skyre under the name "H2RENEW™" and / or described in U.S. Patent Nos. 10,756,361 and / or 10,648,089. At least one hydrogen pump 408 may include multiple pumps (e.g., multiple membrane stacks) connected in series and / or in parallel to achieve a higher overall hydrogen recovery fraction and / or a higher delivery rate. In some embodiments, at least one hydrogen pump 408 may withstand at least about 0.5% molar fraction of CO, including at most about 1% molar fraction of CO, in the dehydrated anode exhaust stream provided to at least one hydrogen pump 408.
[0043] In one embodiment, at least one hydrogen pump 408 can recover more than 80% of the hydrogen in the dehydrated anode exhaust stream and output more than 99% pure compressed hydrogen product via a compressed hydrogen product conduit 410. For example, the compressed hydrogen product can be at least 99.99% pure (i.e., dry) hydrogen, which can be pressurized to 1 psig to 10,000 psig, such as 15 psig to 2,000 psig, for example, 15 psig to 150 psig. In various embodiments, the compressed hydrogen product produced by at least one hydrogen pump 408 can be suitable for use or storage without additional mechanical compression or drying.
[0044] Referring again to FIG2, the compressed hydrogen product in the compressed hydrogen product pipeline 410 can be provided to the separator 411. The separator 411 can be, for example, a computer-controlled or operator-controlled valve or any other suitable fluid separation device, such as a passive separator having an opening or gap in the fluid pipeline. A first portion of the compressed hydrogen product can be provided from the separator 403 to the hydrogen recirculation pipeline 412A for further use in the fuel cell system 10. A second portion of the compressed hydrogen product can be provided from the separator 403 to the hydrogen storage pipeline 413 for storage and / or distribution or sale of the compressed hydrogen product. In some embodiments, the hydrogen storage pipeline 413 can provide the compressed hydrogen product directly to one or more hydrogen storage containers 414 connected to the hydrogen storage pipeline 413. Alternatively, one or more compressors (not shown in Figure 2) may be coupled to a hydrogen storage pipeline and may be configured to further compress the compressed hydrogen product to a pressure suitable for storage in one or more hydrogen storage containers 414.
[0045] In various embodiments, the hydrogen recirculation conduit 412A can be used to provide compressed hydrogen products to one or more locations in the fuel cell system 10. In some embodiments, the hydrogen recirculation conduit 412A can provide at least a portion of the compressed hydrogen products to a fuel source 400, which may be, for example, a natural gas supply.
[0046] Alternatively, in some embodiments, at least a portion of the compressed hydrogen product may be provided to the inlet fuel stream for the fuel cell system 10. In some embodiments, the compressed hydrogen product may be provided downstream of one or more pretreatment units 402 (e.g., desulfurizers) of the fuel cell system 10 to the inlet fuel. In one embodiment shown in FIG2, a separator 415 may direct at least a portion of the compressed hydrogen product from hydrogen recirculation line 412A to hydrogen recirculation line 412B, which may provide at least a portion of the compressed hydrogen product to fuel inlet line 300A.
[0047] Alternatively, in some embodiments, at least a portion of the compressed hydrogen product may be provided to one or more anode recirculation loops in the heatbox 100. In various embodiments, the compressed hydrogen product may be provided to the anode recirculation loops of all heatboxes 100 of the fuel cell system 10. In one embodiment shown in FIG2, one or more separators 416 may direct at least a portion of the compressed hydrogen product from hydrogen recirculation line 412A to one or more hydrogen recirculation lines 412C. Each of the anode recirculation lines 412C may be fluidly connected to the anode recirculation loop of the corresponding heatbox 100. The compressed hydrogen product provided to the anode recirculation loop of the heatbox 100 may be mixed with both anode recirculation and fresh fuel in the anode recirculation loop and may enter the heatbox 100 via fuel line 300D.
[0048] In some embodiments, at least a portion of the compressed hydrogen product may also be provided to the ATO 130 of one or more heatboxes 100 of the fuel cell system 10. In embodiments, the compressed hydrogen product may be provided to the ATO 130 during the start-up of the heatbox 100 or other transient situations and may be used for thermal management of the heatbox 100. In the embodiment shown in FIG2, one or more hydrogen recirculation lines 412D may selectively redirect a portion of the compressed hydrogen product to the ATO 130 of one or more corresponding heatboxes 100. In some embodiments, the hydrogen recirculation line 412D may be fluidly coupled to the anode exhaust line 308D for guiding the compressed hydrogen product to the corresponding ATO 130. By providing hydrogen to the ATO 130, the temperature of the heatbox 100 is maintained at a near-constant temperature, or maintained as close as possible to a constant or actual temperature. Considering other variations (such as changes in ambient temperature, intentional changes in airflow, etc.), there is no predetermined flow control for the feed flow of the ATO 130. In some configurations, a proportional solenoid valve can be used to control the flow rate within + / - 3-5%. Other configurations allow for further flow control (e.g., + / - 0.5%), but these other configurations are expensive.
[0049] In embodiments, the compressed hydrogen product is sufficiently pure (i.e., dry) to be recyclable for use in the fuel cell system 10 without any additional processing or conditioning. Additionally, in some embodiments, the dried compressed hydrogen product can be supplied to various components / locations of the fuel cell system 10 without requiring tracing and insulation of the conduits 412A, 412B, 412C, 412D carrying the compressed hydrogen product to prevent water condensation. The dried compressed hydrogen product may also avoid condensation in undesirable locations within the fuel cell system 10, such as in a desulfurization tank.
[0050] If the compressed hydrogen product is not sufficiently dry for use in the fuel cell system 10 or its components, a refrigerated condenser may be used as appropriate to further reduce the water content of the compressed hydrogen product before it is used in the fuel cell system 10.
[0051] In various embodiments, the system controller 225 (see FIG. 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 a non-limiting example, during steady-state operation of the fuel cell system 10, all or almost all of the compressed hydrogen product can be supplied to the heat box 100 of the fuel cell system 10. Any 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. One advantage of recycling most of the compressed hydrogen product to the fuel cell system 10 is that the need to meet the precise and high fuel utilization targets of the fuel cell system 10 may be reduced as more hydrogen product is recycled as fuel. With a relatively large amount of recycled hydrogen product, a lower utilization rate per use can still support a high overall fuel utilization rate of the fuel cell system 10. In addition, by reducing the fuel utilization rate of the fuel cell system 10 as needed, the amount of hydrogen product supplied to one or more hydrogen storage containers 414 can be increased.
[0052] Referring again to Figure 2, the unpumped effluent from at least one hydrogen pump 408 may primarily contain 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% molar fraction of H₂, such as 0-5% molar fraction of H₂, 0-1% molar fraction of CO, and 0-1% molar fraction of nitrogen. Liquid water may be removed from at least one hydrogen pump 408 via a water discharge conduit 417, and the liquid water in conduit 417 may be purified and / or reused, as appropriate. Unpumped gaseous effluent from at least one hydrogen pump 408 may be supplied from at least one hydrogen pump 408 to an effluent conduit 418.
[0053] In some embodiments, effluent from at least one hydrogen pump may be fed from effluent conduit 418 to blower 419, which may be any suitable fluid (e.g., gas) blower, pump, compressor, etc. Blower 419 may "pull" unpumped effluent from at least one hydrogen pump 408. Blower 419 may further compress the effluent, for example, to a pressure between 2-15 psig. The heat of compression of the unpumped effluent may raise its temperature. This may preheat the effluent for subsequent catalytic or thermal reactions, configured to oxidize some or all of the residual H2 and CO in the effluent. The compression of the effluent may also separate the compression from subsequent CO2 compression, dehydration, and / or liquefaction processes that may be performed. In embodiments where blower 419 is present, as selected, the compressed effluent from blower 419 may be provided to effluent conduit 420. In some cases, adjusting a large compressor with a high compression ratio (i.e., changing the compressor speed) can be difficult. For example, a small change in compressor speed can draw too much or too little gas from the pipeline, causing upstream pressure disturbances. However, small blowers have lower gain, and small speed adjustments have less impact on flow rate and inlet pressure. In some cases, a small storage capacity downstream of the blower can be used to provide some capacitance to the system for pressure control. For example, the downstream storage capacity can be on the order of a one-minute residence time.
[0054] In various embodiments, the compressed effluent from blower 419 may be provided to oxidation reactor 421 via effluent conduit 420, as appropriate. Oxidation reactor 421 may be a catalytic or thermal oxidation reactor configured to reduce or eliminate residual H2 and CO content from the effluent prior to subsequent CO2 treatment steps. Oxygen source 422 may be coupled to oxidation reactor 421 and may provide oxygen for the oxidation reaction. In some embodiments, oxygen source 422 may include a blower. Alternatively or additionally, oxygen source 422 may be an oxygen generator or oxygen storage device that provides purified oxygen for the oxidation reaction. In embodiments where oxidation reactor 421 is present, as appropriate, effluent from oxidation reactor 421 may be provided to effluent conduit 423, which may consist substantially entirely of H2O and CO2.
[0055] In some embodiments, system 10 may optionally include a carbon dioxide treatment device 424 operatively 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 is operable to compress and / or cool the effluent received from at least one hydrogen pump 408, which may be compressed by a blower 419 and / or undergo oxidation in an oxidation reactor 421. The carbon dioxide treatment device 424 may, as appropriate, be a condenser and / or dryer configured to remove water from the effluent. In some embodiments, the carbon dioxide treatment device 424 may also convert the effluent into liquefied CO2 products. Water removed from the effluent may, as appropriate, be removed from the carbon dioxide treatment device 424 via a water discharge conduit 425 for purification and / or reuse, as appropriate. The remaining portion of the purified or pure CO2 effluent may be supplied via conduit 426 to one or more CO2 storage containers 427 for CO2 storage and / or sealing, or may be used in chemical processes, beverage carbonation, etc. In some embodiments, the one or more CO2 storage containers may include one or more cryogenic storage devices configured to convert CO2 into dry ice for storage.
[0056] FIG3 schematically illustrates a fuel cell system 20 according to another embodiment of the present invention. The fuel cell system 20 of FIG3 may be similar to the fuel cell system 10 described above with reference to FIG2. Therefore, for the sake of brevity, repeated descriptions of similar components are omitted. The fuel cell system 20 of FIG3 may differ from the fuel cell system 10 of FIG2, wherein lower pressure and higher pressure hydrogen pumps may be used to recover hydrogen products.
[0057] Specifically, referring to FIG3, a separator 450 (e.g., a valve, passive separator, etc.) located in the anode exhaust duct 308L can direct a portion of the partially hydrated anode exhaust stream to the anode exhaust duct 451. The remaining portion of the partially hydrated anode exhaust stream in the anode exhaust duct 308L can be provided to at least one low-pressure hydrogen pump 452. The at least one low-pressure hydrogen pump 452 can be configured to pump hydrogen separated from the anode exhaust stream to a relatively low pressure (e.g., 1-150 psig). In various embodiments, the 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 the at least one low-pressure hydrogen pump 452 can be provided to the hydrogen recirculation duct 412A for further use in the fuel cell system 20 as described above with reference to FIG2. The residual effluent from at least one low-pressure hydrogen pump 452 can be supplied to effluent conduit 418 and can continue to a blower 419, an oxidation reactor 421, and a carbon dioxide treatment device 424, as appropriate, for CO2 separation, as described above with reference to Figure 2. Liquid water from the effluent can be recovered via water discharge conduit 453, as appropriate.
[0058] Referring again to Figure 3, a portion of the hydrated anode exhaust stream located within the anode exhaust conduit 451 can be supplied to at least one high-pressure hydrogen pump 454. The at least one high-pressure hydrogen pump 454 can be configured to pump hydrogen separated from the anode exhaust stream to a relatively high pressure (e.g., 200 to 10,000 psig). In various embodiments, at least one high-pressure hydrogen pump 452 can pump hydrogen to a pressure suitable for hydrogen storage and / or commercial sale of purified hydrogen products. The compressed hydrogen product from the at least one high-pressure hydrogen pump 454 can be supplied to one or more hydrogen storage containers 414 via a hydrogen product conduit 456. The remaining gaseous effluent from the at least one high-pressure hydrogen pump 454 can be supplied to an effluent conduit 457, and liquid water from the effluent can be recovered via a water discharge conduit 453, if applicable. In some embodiments, the effluent conduit 457 may supply effluent from at least one high-pressure hydrogen pump 454 to a blower 419, an oxidation reactor 421, and a carbon dioxide treatment device 424, as appropriate, for CO2 separation, as described above with reference to FIG2.
[0059] Generally, hydrogen products intended for storage and / or commercial sale may require higher pressure levels than hydrogen products recycled 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 stream in parallel. In some embodiments, one or more buffer tanks (not shown in FIG. 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 rate of the parallel anode exhaust stream fed to the respective hydrogen pumps 452, 454.
[0060] Therefore, the fuel cell systems 10 and 20 shown in Figures 1 to 3 can utilize or recapture substantially all of the hydrogen content and substantially all of the carbon content of the input fuel supplied to the fuel cell systems 10 and 20. This can provide increased fuel utilization for the fuel cell systems 10 and 20.
[0061] FIG4 schematically illustrates a fuel cell system 30 according to another embodiment of the present invention. The fuel cell system 30 of FIG4 may be similar to the fuel cell systems 10 and 20 described above with reference to FIG2 and 3. Therefore, for the sake of brevity, repeated descriptions of similar components are omitted. The fuel cell system 30 of FIG4 may differ from the fuel cell systems 10 and 20 of FIG2 and 3, wherein a carbon dioxide pump may be used to separate at least a portion of CO2 from the anode exhaust stream.
[0062] 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 stream from the heatbox 100 of the fuel cell system 30. The condenser 406 may be configured to condense water vapor into liquid water and reduce the temperature of the anode exhaust stream, such that the temperature and / or water content of the anode exhaust stream are within the operating range of the carbon dioxide pump 600. The liquid water condensed from the anode exhaust stream may be removed via a water discharge pipe 407. An anode exhaust pipe 308L may provide a portion of the dehydrated anode exhaust stream from the condenser 406 to the inlet of at least one carbon dioxide pump 600.
[0063] At least one carbon dioxide pump 600 may include one or more electrochemical carbon dioxide pumps. The at least one electrochemical carbon dioxide pump 600 may be configured to pump CO2 from a low-pressure anode exhaust stream to a high-pressure, nearly pure CO2 product, which may also contain water. In some embodiments, the at least one electrochemical carbon dioxide pump may include a scrubber and separator (i.e., a concentrator) that electrochemically pumps pure carbon dioxide through the membrane when a current or voltage is applied across the polymer membrane. In various embodiments, the at least one electrochemical carbon dioxide pump 600 may include a high-pressure carbon dioxide separation and compression system, which may be obtained from Skyre under the name "CO2RENEW™" and / or described in U.S. Patent Application Publication No. 2020 / 0222852. The at least one carbon dioxide pump 600 may include multiple pumps (e.g., multiple membrane stacks) connected in series and / or in parallel to achieve a higher overall CO2 recovery fraction and / or a higher delivery rate.
[0064] 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, for example 1-5 psig, 5-150 psig, or 150-5,000 psig. In some embodiments, the compressed CO2 product produced by at least one carbon dioxide pump 600 may be suitable for use, storage, or sequestration without additional mechanical compression.
[0065] In some embodiments, compressed CO2 product from at least one CO2 pump 600 may be provided via conduit 602 to a CO2 treatment device 424. The CO2 treatment device 424 may remove any residual water from the compressed CO2 product, for example by temperature swing adsorption (TSA) and / or pressure swing adsorption (PSA). Water removed from the compressed CO2 product may, as appropriate, be removed via a water discharge conduit 425 for purification and / or reuse. The compressed CO2 product may, as appropriate, undergo further compression to pressurize the CO2 product to a pressure suitable for storage, use, and / or sequestration. In some embodiments, the compressed CO2 product may be liquefied or solidified into dry ice. After treatment by the CO2 treatment device 424, the compressed CO2 product, which may include purified or pure CO2, may be provided via conduit 426 to one or more CO2 storage containers 427 for CO2 storage and / or sequestration, or for use in chemical processes, beverage carbonation, etc.
[0066] Referring again to Figure 4, the unpumped effluent from at least one carbon dioxide pump 600 may contain hydrogen, water (e.g., water vapor 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, the liquid water from the unpumped effluent may be removed via water discharge line 601 as appropriate. The remaining unpumped effluent from at least one carbon dioxide pump 600 may be provided to line 603 for recirculation back to the fuel cell system 30.
[0067] In various embodiments, the unpumped effluent from at least one carbon dioxide pump 600 may include substantially all of the hydrogen and carbon monoxide from the anode exhaust stream. The concentration of hydrogen and carbon monoxide in the unpumped effluent will generally be greater than their concentration in the anode exhaust stream because most of the carbon dioxide and some water from the anode exhaust stream are removed by at least one carbon dioxide pump 600. This allows the effluent in conduit 603 to be advantageously used in the fuel cell system 30, including as a fuel source or supplemental fuel for stack 102 and / or ATO 130. In various embodiments, at least one blower 604 may be in fluid communication with conduit 603. At least one blower 604 may include any suitable fluid (e.g., gas) blower, pump, compressor, etc. At least one blower 604 may compress the effluent 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 effluent to different pressures for different uses in the fuel cell system 10. For example, a first blower 604, fluidly connected to anode recirculation line 412C, can be used to increase the pressure of the effluent from the anode recirculation loop fed to heatbox 100 by between 1 psi and 2 psi. At least a portion of the effluent supplied to heatbox 100 can also be supplied to the ATO 130 of heatbox 100 for thermal management and / or nitrogen removal from the ATO 130. A proportional solenoid valve can be used to control a portion of the effluent fed to the corresponding heatbox 100's ATO 130. An additional blower 604, fluidly connected to anode recirculation line 412B, can be used to increase the pressure of the effluent from the fuel inlet stream fed to fuel cell system 30 by between 10 psi and 15 psi.
[0068] In the fuel cell system 30 shown in Figure 4, since almost all fuel can be recycled as a separated carbon dioxide product and / or as recycle fuel for the fuel cell system 30, the per-fuel utilization rate of the fuel cell system 30 can be reduced. Furthermore, since any residual CO2 in the effluent stream from at least one CO2 pump 600 is recycled through the fuel cell system 30 and ultimately from the heatbox 100 to the anode exhaust stream, at least one CO2 pump 600 does not need to have an extremely high CO2 recovery rate. In some embodiments, the per-fuel CO2 recovery rate of at least one CO2 pump 600 can be between 70% and 90%. This achieves almost 100% overall CO2 recovery for the fuel cell system 30, minus the ATO 130 that can be recycled to the heatbox 100 and / or the small amount of CO2 generated therefrom.
[0069] Depending on the CO tolerance of at least one CO2 pump 600, in some embodiments, the WGS reactor 405 and anode exhaust conditioning unit 404 may be eliminated from the fuel cell system 30 of FIG4. Therefore, the anode exhaust from manifold 104 can be fed to condenser 406, which can be configured to regulate the anode exhaust flow such that the temperature and / or water content of the anode exhaust flow is within the operating range of at least one CO2 pump 600. In this case, the anode exhaust flow entering at least one CO2 pump 600 and the effluent from at least one CO2 pump 600 may have relatively high concentrations of H2 and CO.
[0070] FIG5 schematically illustrates a fuel cell system 40 according to another embodiment of the present invention. The fuel cell system 40 of FIG5 may be similar to the fuel cell system 30 described above with reference to FIG4. Therefore, for the sake of brevity, repeated descriptions of similar components are omitted. The fuel cell system 40 of FIG5 may differ from the fuel cell system 30 of FIG4 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 provided from the condenser 406 to at least one hydrogen pump 408 via the anode exhaust conduit 308L. At least one hydrogen pump 408 may produce compressed hydrogen products as described above, which may be provided to conduit 410. The compressed hydrogen products from at least one hydrogen pump 408 may be recycled to the fuel cell system 30 and / or provided to one or more hydrogen storage containers 414 for storage and potential commercial sale. In the embodiment shown in Figure 5, the separator 413 can be used to supply a portion of the compressed hydrogen product to one or more hydrogen storage containers 414 via hydrogen storage pipe 413, while the remaining portion of the compressed hydrogen product can be recycled via pipe 412A for use in a fuel cell system.
[0071] Unpumped effluent from at least one hydrogen pump 408 may primarily contain water (e.g., water vapor and / or liquid water) and carbon dioxide, as well as smaller amounts of hydrogen, carbon monoxide, nitrogen, and other impurities. Liquid water from the unpumped effluent may be removed via water discharge line 417, if applicable. The remaining effluent may be supplied via line 308M to at least one carbon dioxide pump 600. At least one carbon dioxide pump 600 may separate most (e.g., 70% or more) of the CO2 from the effluent and supply compressed CO2 product, as described above with reference to Figure 4. The compressed CO2 product may be supplied via line 602 to CO2 treatment unit 424, if applicable.
[0072] Unpumped effluent from at least one carbon dioxide pump 600 may include 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 trace amounts of hydrogen, carbon monoxide, nitrogen, and other impurities. Liquid water from the unpumped effluent may be removed via water discharge line 601, if necessary. Remaining effluent may be supplied to line 603 for use in the fuel cell system 40 as described above.
[0073] One advantage of providing at least one hydrogen pump 408 upstream of at least one carbon dioxide pump 600 is that the at least one hydrogen pump 408 can reduce the gas flow rate of the process stream before feeding the process stream to at least one carbon dioxide pump 600. Additionally, by removing hydrogen using at least one hydrogen pump 408, the concentration of CO2 in the process stream fed to at least one carbon dioxide pump 600 can be increased. The system 40 of Figure 5 can also produce pure or purified hydrogen products, which can be stored for later use and / or sale.
[0074] FIG6 schematically illustrates a fuel cell system 50 according to another embodiment of the present invention. The fuel cell system 50 of FIG5 may be similar to the fuel cell system 10 described above with reference to FIG2. Therefore, for the sake of brevity, repeated descriptions of similar components are omitted. The fuel cell system 50 of FIG3 may differ from the fuel cell system 10 of FIG2 by adding at least one carbon dioxide pump 600 upstream of at least one hydrogen pump 408. In various embodiments, the anode exhaust stream may be provided from the condenser 406 to at least one carbon dioxide pump 600 via the anode exhaust conduit 308L. The at least one carbon dioxide pump 600 may separate most (e.g., 70% or more) of the CO2 from the anode exhaust stream and provide compressed CO2 products, as described above with reference to FIG4. The compressed CO2 products may be provided to the CO2 processing device 424 via conduit 602, if applicable.
[0075] Unpumped effluent from at least one carbon dioxide pump 600 may include a hydrogen-rich process stream comprising water (e.g., water vapor and / or liquid water), hydrogen, and carbon dioxide not separated by at least one carbon dioxide pump 600, as well as trace amounts of carbon monoxide, nitrogen, and other impurities. Liquid water from the unpumped effluent may be removed via water discharge line 601, if necessary. Remaining effluent may be supplied to at least one hydrogen pump 408 via line 604.
[0076] At least one hydrogen pump 408 can produce the compressed hydrogen product as described above, which can be provided to line 410. The compressed hydrogen product from at least one hydrogen pump 408 can be recycled to fuel cell system 30 and / or provided to one or more hydrogen storage containers 414 for storage and potential commercial sale. In the embodiment shown in FIG6, separator 411 can be used to provide a portion of the compressed hydrogen product to one or more hydrogen storage containers 414 via hydrogen storage line 413, while the remaining portion of the compressed hydrogen product can be recycled via line 412A for use in fuel cell system.
[0077] Unpumped gaseous effluent from at least one hydrogen pump 408 may be supplied from at least one hydrogen pump 408 to effluent conduit 418 and may be fed, as appropriate, to blower 419 and oxidation reactor 421, which are configured to reduce or eliminate residual H2 and CO from the effluent as previously described with reference to FIG2. Residual effluent, which may consist primarily of water and CO2, may be supplied via conduit 605 to CO2 treatment unit 424 for recovery, storage and / or use of residual CO2 as described above.
[0078] The prior description of the disclosed embodiments is provided to enable those skilled in the art to make or use the invention. Those skilled in the art will readily understand various modifications to these embodiments, and the general principles defined herein can be applied to other embodiments without departing from the scope of the invention. Therefore, the invention 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. [Simplified Explanation of the Diagram]
[0007] The accompanying drawings, which are incorporated herein and constitute a part of this specification, illustrate exemplary embodiments of the invention and, together with the general description given above and the detailed description given below, serve to explain the features of the invention.
[0008] Figure 1 is a schematic diagram of the heat box of a solid oxide fuel cell system according to various embodiments.
[0009] Figure 2 is a schematic diagram of the components of a fuel cell system according to an embodiment of the present invention.
[0010] Figure 3 is a schematic diagram of the components of a fuel cell system according to another embodiment of the present invention.
[0011] Figure 4 is a schematic diagram of the components of a fuel cell system according to another embodiment of the present invention.
[0012] Figure 5 is a schematic diagram of the components of a fuel cell system according to another embodiment of the present invention.
[0013] Figure 6 is a schematic diagram of the components of a fuel cell system according to another embodiment of the present invention.
Claims
1. A fuel cell system comprising: at least one heatbox containing a fuel cell stack and generating anode exhaust products; at least one hydrogen pump; at least one product conduit fluidly connecting the anode exhaust product outlet of the heatbox to the inlet of the 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 at least one effluent conduit connected to the unpumped effluent outlet of the at least one hydrogen pump.
2. The fuel cell system of claim 1, wherein the fuel cell system further comprises: a plurality of heat boxes, each containing a fuel cell stack and generating anode exhaust products; at least one product conduit fluidly connecting the anode exhaust product outlet of each of the plurality of heat boxes to a manifold; and at least one product conduit fluidly connecting the outlet of the manifold to the inlet of the at least one hydrogen pump.
3. The fuel cell system of claim 2, wherein each of the plurality of hot boxes includes a first anode exhaust outlet fluidly connected to the manifold via at least one product pipe, and a second anode exhaust outlet fluidly connected to the manifold via at least one product pipe.
4. The fuel cell system of claim 3, wherein the anode exhaust product discharged from each of the heatboxes through the first anode exhaust outlet includes anode exhaust that has passed through the anode exhaust cooler of the respective heatbox, and the anode exhaust product discharged from each of the heatboxes through the second anode exhaust outlet includes anode exhaust that bypasses the anode exhaust cooler of the respective heatbox.
5. The fuel cell system of claim 1, further comprising a blower fluidly connected to the at least one effluent conduit, the blower being configured to compress unpumped effluent products from the unpumped effluent outlet of the at least one hydrogen pump.
6. The fuel cell system of claim 5 further includes an oxidation reactor fluidly connected to the outlet of the blower via at least one effluent conduit, the oxidation reactor being configured to reduce or eliminate residual H2 and CO content in the unpumped effluent products compressed by the blower.
7. The fuel cell system of claim 6 further includes a carbon dioxide treatment device fluidly connected to the outlet of the oxidation reactor via at least one effluent conduit, the carbon dioxide treatment device being configured to convert the unpumped effluent product into purified or pure CO2 product.
8. 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 comprising more than 99% by volume hydrogen.
9. The fuel cell system of claim 8, wherein the compressed hydrogen product pipeline is fluidly connected to at least one hydrogen recirculation pipeline, the at least one hydrogen recirculation pipeline being configured to recirculate at least a portion of the compressed hydrogen product for use by the fuel cell system.
10. The fuel cell system of claim 9, wherein the compressed hydrogen product pipeline is fluidly connected to at least one hydrogen recirculation pipeline, the at least one hydrogen recirculation pipeline being fluidly connected to the anode recirculation loop of the heatbox of the fuel cell system.
11. The fuel cell system of claim 9, wherein the compressed hydrogen product pipeline is fluidly connected to at least one hydrogen recirculation pipeline, the at least one hydrogen recirculation pipeline being fluidly connected to the anode tail gas oxidizer (ATO) of the hot box of the fuel cell system.
12. The fuel cell system of claim 9, wherein the compressed hydrogen product pipeline is fluidly connected to at least one hydrogen recirculation pipeline, the at least one hydrogen recirculation pipeline being fluidly connected to at least one of the fuel source of the fuel cell system and the fuel inlet pipeline of one or more heat boxes of the fuel cell system.
13. The fuel cell system of claim 9, wherein the at least one hydrogen recirculation 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 containers.
14. The fuel cell system of claim 3, further comprising: a water-gas shift (WGS) reactor, at least one product line fluidly connecting the outlet of the manifold to the inlet of the WGS reactor; and a condenser, at least one product line fluidly connecting the outlet of the WGS reactor to the inlet of the condenser, and at least one product line fluidly connecting the outlet of the condenser to the inlet of the at least one hydrogen pump.
15. The fuel cell system of claim 1, wherein the at least one hydrogen pump comprises: a low-pressure hydrogen pump, at least one product conduit fluidly connected to the inlet of the low-pressure hydrogen pump for receiving a first portion of the anode exhaust product, wherein the compressed hydrogen product generated by the low-pressure hydrogen pump is recycled for use in the fuel cell system; and a high-pressure hydrogen pump, at least one product conduit fluidly connected to the inlet of the high-pressure hydrogen pump for receiving a second portion of the anode exhaust product, wherein the compressed hydrogen product generated by the high-pressure hydrogen pump is provided to one or more hydrogen storage containers.
16. The fuel cell system of claim 1, wherein the fuel cell system comprises a solid oxide fuel cell (SOFC) system.
17. The fuel cell system of claim 1, further comprising at least one carbon dioxide pump, wherein: (a) The inlet of the at least one carbon dioxide pump is fluidly connected to the unpumped effluent outlet of the at least one hydrogen pump via at least one unpumped effluent conduit, connected to the compressed carbon dioxide product outlet of the at least one carbon dioxide pump via a compressed carbon dioxide product conduit, and at least one unpumped effluent recirculation conduit is coupled to the unpumped effluent outlet of the at least one carbon dioxide pump to recirculate the unpumped effluent from the at least one carbon dioxide pump for use by the fuel cell system; or (b) At least one product conduit is fluidly connected to the anode exhaust product outlet of the heatbox to the inlet of the at least one carbon dioxide pump, connected to the compressed carbon dioxide product outlet of the at least one carbon dioxide pump via a compressed carbon dioxide product conduit, and at least one unpumped effluent recirculation conduit is coupled to the unpumped effluent outlet of the at least one carbon dioxide pump to supply the unpumped effluent from the at least one carbon dioxide pump to the inlet of the at least one hydrogen pump.
18. A fuel cell system comprising: at least one heatbox containing a fuel cell stack and generating anode exhaust products; at least one carbon dioxide pump; at least one product conduit fluidly connecting the anode exhaust product outlet of the heatbox 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 effluent conduit connected to the unpumped effluent outlet of the at least one carbon dioxide pump.
19. The fuel cell system of claim 18, wherein the at least one carbon dioxide pump comprises an electrochemical carbon dioxide pump configured to remove at least about 70% of the carbon dioxide from the anode exhaust product supplied to the at least one carbon dioxide pump, and to produce compressed carbon dioxide product and unpumped effluent.
20. The fuel cell system of claim 19, further comprising at least one blower fluidly connected to the at least one effluent conduit, the blower being configured to recirculate the unpumped effluent from the at least one carbon dioxide pump for use by the fuel cell system.
21. A method of operating a fuel cell system, comprising: providing a fuel inlet flow to at least one heatbox of the fuel cell system; generating an anode exhaust product flow from the at least one heatbox of the fuel cell system; providing 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 recycling at least a portion of the compressed hydrogen products to the at least one heatbox of the fuel cell system.
22. The method of claim 21 further comprises at least one of the following: generating purified or pure CO2 product from the unpumped effluent from the at least one hydrogen pump, and providing a portion of the compressed hydrogen product to at least one hydrogen storage container.
23. A method of operating a fuel cell system, comprising: providing a fuel inlet flow to at least one heatbox of the fuel cell system; generating an anode exhaust product flow from the at least one heatbox of the fuel cell system; providing the anode exhaust product flow to at least one carbon dioxide pump; generating compressed carbon dioxide product and unpumped effluent in the at least one carbon dioxide pump; and recycling at least a portion of the unpumped effluent from the carbon dioxide pump to the at least one heatbox of the fuel cell system.
24. The method of claim 23, further comprising: generating a purified or pure CO2 product from the compressed carbon dioxide product from the at least one carbon dioxide pump.