US20140065020A1 - Hydrogen generation assemblies - Google Patents

Abstract

Hydrogen generation assemblies and their components are disclosed. In some embodiments, the assemblies may include a pump controller configured to select a flowrate from a plurality of flowrates based on detected pressure, and to operate the pump at the selected flowrate. In some embodiments, the assemblies may include a purge valve assembly configured to allow at least one pressurized gas to flow through a purge conduit from a pressurized gas assembly to a fuel processing assembly when power to the fuel processing assembly is interrupted. In some embodiments, the assemblies may include a damper controller configured to move a damper between fully open and closed positions based, at least in part, on detected temperature in a hydrogen-producing region. In some embodiments, the assemblies may include a reformer controller configured to operate a fuel processing assembly between run and standby modes based, at least in part, on detected pressure.

Description

BACKGROUND OF THE DISCLOSURE
• A hydrogen generation assembly is an assembly that converts one or more feedstocks into a product stream containing hydrogen gas as a majority component. The feedstocks may include a carbon-containing feedstock and, in some embodiments, also may include water. The feedstocks are delivered to a hydrogen-producing region of the hydrogen generation assembly from a feedstock delivery system, typically with the feedstocks being delivered under pressure and at elevated temperatures. The hydrogen-producing region is often associated with a temperature modulating assembly, such as a heating assembly or cooling assembly, which consumes one or more fuel streams to maintain the hydrogen-producing region within a suitable temperature range for effectively producing hydrogen gas. The hydrogen generation assembly may generate hydrogen gas via any suitable mechanism(s), such as steam reforming, autothermal reforming, pyrolysis, and/or catalytic partial oxidation.
• The generated or produced hydrogen gas may, however, have impurities. That gas may be referred to as a mixed gas stream that contains hydrogen gas and other gases. Prior to using the mixed gas stream, it must be purified, such as to remove at least a portion of the other gases. The hydrogen generation assembly may therefore include a hydrogen purification device for increasing the hydrogen purity of the mixed gas stream. The hydrogen purification device may include at least one hydrogen-selective membrane to separate the mixed gas stream into a product stream and a byproduct stream. The product stream contains a greater concentration of hydrogen gas and/or a reduced concentration of one or more of the other gases from the mixed gas stream. Hydrogen purification using one or more hydrogen-selective membranes is a pressure driven separation process in which the one or more hydrogen-selective membranes are contained in a pressure vessel. The mixed gas stream contacts the mixed gas surface of the membrane(s), and the product stream is formed from at least a portion of the mixed gas stream that permeates through the membrane(s). The pressure vessel is typically sealed to prevent gases from entering or leaving the pressure vessel except through defined inlet and outlet ports or conduits.
• The product stream may be used in a variety of applications. One such application is energy production, such as in electrochemical fuel cells. An electrochemical fuel cell is a device that converts fuel and an oxidant to electricity, a reaction product, and heat. For example, fuel cells may convert hydrogen and oxygen into water and electricity. In those fuel cells, the hydrogen is the fuel, the oxygen is the oxidant, and the water is a reaction product. Fuel cell stacks include a plurality of fuel cells and may be utilized with a hydrogen generation assembly to provide an energy production assembly.
• Examples of hydrogen generation assemblies, hydrogen processing assemblies, and/or components of those assemblies are described in U.S. Pat. Nos. 5,861,137; 6,319,306; 6,494,937; 6,562,111; 7,063,047; 7,306,868; 7,470,293; 7,601,302; 7,632,322; U.S. Patent Application Publication Nos. 2006/0090397; 2006/0272212; 2007/0266631; 2007/0274904; 2008/0085434; 2008/0138678; 2008/0230039; 2010/0064887; and U.S. patent application Ser. No. 13/178,098. The complete disclosures of the above patents and patent application publications are hereby incorporated by reference for all purposes.
SUMMARY OF THE DISCLOSURE
• Some embodiments may provide a hydrogen generation assembly. In some embodiments, the hydrogen generation assembly may include a fuel processing assembly configured to receive a feed stream and produce a product hydrogen stream from the feed stream. The hydrogen generation assembly may additionally include a feed assembly configured to deliver the feed stream to the fuel processing assembly. The feed assembly may include a feed tank configured to contain feedstock for the feed stream, and a feed conduit fluidly connecting the feed tank and the fuel processing assembly. The feed assembly may additionally include a pump configured to deliver the feed stream at a plurality of flowrates to the fuel processing assembly via the feed conduit. The hydrogen generation assembly may further include a control system. The control system may include a feed sensor assembly configured to detect pressure in the feed conduit downstream from the pump. The control system may additionally include a pump controller configured to select a flowrate from the plurality of flowrates based on the detected pressure in the feed conduit, and to operate the pump at the selected flowrate.
• In some embodiments, the hydrogen generation assembly may include a fuel processing assembly configured to receive a feed stream and produce a product hydrogen stream from the feed stream. The hydrogen generation assembly may additionally include a pressurized gas assembly configured to receive at least one container of pressurized gas that is configured to purge the fuel processing assembly. The hydrogen generation assembly may further include a purge conduit configured to fluidly connect the pressurized gas assembly and the fuel processing assembly. The hydrogen generation assembly may additionally include a purge valve assembly configured to allow the at least one pressurized gas to flow through the purge conduit from the pressurized gas assembly to the fuel processing assembly when power to the fuel processing assembly is interrupted.
• In some embodiments, the hydrogen generation assembly may include a fuel processing assembly configured to receive a feed stream and to be operable among a plurality of modes, including a run mode in which the fuel processing assembly produces a product hydrogen stream from the feed stream, and a standby mode in which the fuel processing assembly does not produce the product hydrogen stream from the feed stream. The hydrogen generation assembly may additionally include a buffer tank configured to contain the product hydrogen stream, and a product conduit fluidly connecting the fuel processing assembly and the buffer tank. The hydrogen generation assembly may further include a tank sensor assembly configured to detect pressure in the buffer tank, and a control assembly configured to operate the fuel processing assembly between the run and standby modes based, at least in part, on the detected pressure in the buffer tank.
• Some embodiments may provide a steam reforming hydrogen generation assembly configured to receive at least one feed stream and generate a reformate stream containing hydrogen gas as a majority component and other gases. In some embodiments, the steam reforming hydrogen generation assembly may include an enclosure having an exhaust port, and a hydrogen-producing region contained within the enclosure and configured to produce, via a steam reforming reaction, the reformate stream from the at least one feed stream. The steam reforming hydrogen generation assembly may additionally include a reformer sensor assembly configured to detect temperature in the hydrogen-producing region. The steam reforming hydrogen generation assembly may further include a heating assembly configured to receive at least one air stream and at least one fuel stream and to combust the at least one fuel stream within a combustion region contained within the enclosure producing a heated exhaust stream for heating at least the hydrogen-producing region to at least a minimum hydrogen-producing temperature. The steam reforming hydrogen generation assembly may additionally include a damper moveably connected to the exhaust port and configured to move among a plurality of positions including a fully open position in which the damper allows the heated exhaust stream to flow through the exhaust port, a closed position in which the damper prevents the heated exhaust stream from flowing through the exhaust port, and a plurality of intermediate open positions between the fully open and closed positions. The steam reforming hydrogen generation assembly may further include a damper controller configured to move the damper between the fully open and closed positions based, at least in part, on the detected temperature in the hydrogen-producing region.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is a schematic view of an example of a hydrogen generation assembly.
• FIG. 2 is a schematic view of another example of a hydrogen generation assembly.
• FIG. 3 is a partial schematic view of an additional example of a hydrogen generation assembly.
• FIG. 4 is a schematic view of an example of a control assembly.
• FIG. 5 is a graph showing an example of the control assembly ofFIG. 4 receiving a detection signal and conditioning the detection signal to generate a conditioned signal.
• FIG. 6 is a partial schematic view of a further example of a hydrogen generation assembly.
• FIG. 7 is an example of a purge assembly of a hydrogen generation assembly.
• FIG. 8 is another example of a purge assembly of a hydrogen generation assembly.
• FIG. 9 is a partial schematic view of an additional example of a hydrogen generation assembly.
• FIGS. 10-12 are partial schematic views of the hydrogen generation assembly ofFIG. 9 showing another example of a damper and examples of positions for that damper.
• FIG. 13 is a partial schematic view of a further example of a hydrogen generation assembly.
• FIG. 14 is a partial schematic view of another example of a hydrogen generation assembly.
• FIG. 15 is a partial schematic view of the hydrogen generation assembly ofFIG. 14 showing a three-way valve in a flow position.
• FIG. 16 is a partial schematic view of the hydrogen generation assembly ofFIG. 14 showing the three-way valve ofFIG. 15 in a vent position.
• FIG. 17 is a partial schematic view of a further example of a hydrogen generation assembly.
• FIG. 18 is a partial schematic view of the hydrogen generation assembly ofFIG. 17 showing a first valve in an open position and a second valve in a closed position.
• FIG. 19 is a partial schematic view of the hydrogen generation assembly ofFIG. 17 showing the first valve ofFIG. 18 in a closed position and the second valve ofFIG. 18 in an open position.
DETAILED DESCRIPTION OF THE DISCLOSURE
• FIG. 1 shows an example of ahydrogen generation assembly20. Unless specifically excluded hydrogen generation assembly may include one or more components of other hydrogen generation assemblies described in this disclosure. The hydrogen generation assembly may include any suitable structure configured to generate aproduct hydrogen stream21. For example, the hydrogen generation assembly may include afeedstock delivery system22 and afuel processing assembly24. The feedstock delivery system may include any suitable structure configured to selectively deliver at least onefeed stream26 to the fuel processing assembly.
• In some embodiments,feedstock delivery system22 may additionally include any suitable structure configured to selectively deliver at least onefuel stream28 to a burner or other heating assembly offuel processing assembly24. In some embodiments, feedstream26 andfuel stream28 may be the same stream delivered to different parts of the fuel processing assembly. The feedstock delivery system may include any suitable delivery mechanisms, such as a positive displacement or other suitable pump or mechanism for propelling fluid streams. In some embodiments, feedstock delivery system may be configured to deliver feed stream(s)26 and/or fuel stream(s)28 without requiring the use of pumps and/or other electrically powered fluid-delivery mechanisms. Examples of suitable feedstock delivery systems that may be used withhydrogen generation assembly20 include the feedstock delivery systems described in U.S. Pat. Nos. 7,470,293 and 7,601,302, and U.S. Patent Application Publication No. 2006/0090397. The complete disclosures of the above patents and patent application are hereby incorporated by reference for all purposes.
• Feed stream26 may include at least one hydrogen-production fluid30, which may include one or more fluids that may be utilized as reactants to produceproduct hydrogen stream21. For example, the hydrogen-production fluid may include a carbon-containing feedstock, such as at least one hydrocarbon and/or alcohol. Examples of suitable hydrocarbons include methane, propane, natural gas, diesel, kerosene, gasoline, etc. Examples of suitable alcohols include methanol, ethanol, polyols (such as ethylene glycol and propylene glycol), etc. Additionally, hydrogen-production fluid30 may include water, such as when fuel processing assembly generates the product hydrogen stream via steam reforming and/or autothermal reforming. Whenfuel processing assembly24 generates the product hydrogen stream via pyrolysis or catalytic partial oxidation, feedstream26 does not contain water.
• In some embodiments,feedstock delivery system22 may be configured to deliver a hydrogen-production fluid30 that contains a mixture of water and a carbon-containing feedstock that is miscible with water (such as methanol and/or another water-soluble alcohol). The ratio of water to carbon-containing feedstock in such a fluid stream may vary according to one or more factors, such as the particular carbon-containing feedstock being used, user preferences, design of the fuel processing assembly, mechanism(s) used by the fuel processing assembly to generate the product hydrogen stream etc. For example, the molar ratio of water to carbon may be approximately 1:1 to 3:1. Additionally, mixtures of water and methanol may be delivered at or near a 1:1 molar ratio (37 weight % water, 63 weight % methanol), while mixtures of hydrocarbons or other alcohols may be delivered at a water-to-carbon molar ratio greater than 1:1.
• Whenfuel processing assembly24 generatesproduct hydrogen stream21 via reforming, feedstream26 may include, for example, approximately 25-75 volume methanol or ethanol (or another suitable water-miscible carbon-containing feedstock) and approximately 25-75 volume % water. For feed streams that at least substantially include methanol and water, those streams may include approximately 50-75 volume methanol and approximately 25-50 volume % water. Streams containing ethanol or other water-miscible alcohols may contain approximately 25-60 volume % alcohol and approximately 40-75 volume % water. An example of a feed stream forhydrogen generating assembly20 that utilizes steam reforming or autothermal reforming contains 69 volume % methanol and 31 volume % water.
• Althoughfeedstock delivery system22 is shown to be configured to deliver asingle feed stream26, the feedstock delivery system may be configured to deliver two or more feed streams26. Those streams may contain the same or different feedstocks and may have different compositions, at least one common component, no common components, or the same compositions. For example, a first feed stream may include a first component, such as a carbon-containing feedstock and a second feed stream may include a second component, such as water. Additionally, althoughfeedstock delivery system22 may, in some embodiments, be configured to deliver asingle fuel stream28, the feedstock delivery system may be configured to deliver two or more fuel streams. The fuel streams may have different compositions, at least one common component, no common components, or the same compositions. Moreover, the feed and fuel streams may be discharged from the feedstock delivery system in different phases. For example, one of the streams may be a liquid stream while the other is a gas stream. In some embodiments, both of the streams may be liquid streams, while in other embodiments both of the streams may be gas streams. Furthermore, althoughhydrogen generation assembly20 is shown to include a singlefeedstock delivery system22, the hydrogen generation assembly may include two or morefeedstock delivery systems22.
• Fuel processing assembly24 may include a hydrogen-producingregion32 configured to produce anoutput stream34 containing hydrogen gas via any suitable hydrogen-producing mechanism(s). The output stream may include hydrogen gas as at least a majority component and may include additional gaseous component(s).Output stream34 may therefore be referred to as a “mixed gas stream” that contains hydrogen gas as its majority component but which includes other gases.
• Hydrogen-producingregion32 may include any suitable catalyst-containing bed or region. When the hydrogen-producing mechanism is steam reforming, the hydrogen-producing region may include a suitablesteam reforming catalyst36 to facilitate production of output stream(s)34 from feed stream(s)26 containing a carbon-containing feedstock and water. In such an embodiment,fuel processing assembly24 may be referred to as a “steam reformer,” hydrogen-producingregion32 may be referred to as a “reforming region,” andoutput stream34 may be referred to as a “reformate stream.” The other gases that may be present in the reformate stream may include carbon monoxide, carbon dioxide, methane, steam, and/or unreacted carbon-containing feedstock.
• When the hydrogen-producing mechanism is autothermal reforming, hydrogen-producingregion32 may include a suitable autothermal reforming catalyst to facilitate the production of output stream(s)34 from feed stream(s)26 containing water and a carbon-containing feedstock in the presence of air. Additionally,fuel processing assembly24 may include anair delivery assembly38 configured to deliver air stream(s) to the hydrogen-producing region.
• In some embodiments,fuel processing assembly24 may include a purification (or separation)region40, which may include any suitable structure configured to produce at least one hydrogen-rich stream42 from output (or mixed gas)stream34. Hydrogen-rich stream42 may include a greater hydrogen concentration thanoutput stream34 and/or a reduced concentration of one or more other gases (or impurities) that were present in that output stream.Product hydrogen stream21 includes at least a portion of hydrogen-rich stream42. Thus,product hydrogen stream21 and hydrogen-rich stream42 may be the same stream and have the same composition and flow rates. Alternatively, some of the purified hydrogen gas in hydrogen-rich stream42 may be stored for later use, such as in a suitable hydrogen storage assembly and/or consumed by the fuel processing assembly.Purification region40 also may be referred to as a “hydrogen purification device” or a “hydrogen processing assembly.”
• In some embodiments,purification region40 may produce at least onebyproduct stream44, which may contain no hydrogen gas or some hydrogen gas. The byproduct stream may be exhausted, sent to a burner assembly and/or other combustion source, used as a heated fluid stream, stored for later use, and/or otherwise utilized, stored, and/or disposed. Additionally,purification region40 may emit the byproduct stream as a continuous stream responsive to the deliver ofoutput stream34, or may emit that stream intermittently, such as in a batch process or when the byproduct portion of the output stream is retained at least temporarily in the purification region.
• Fuel processing assembly24 may include one or more purification regions configured to produce one or more byproduct streams containing sufficient amounts of hydrogen gas to be suitable for use as a fuel stream (or a feedstock stream) for a heating assembly for the fuel processing assembly. In some embodiments, the byproduct stream may have sufficient fuel value or hydrogen content to enable a heating assembly to maintain the hydrogen-producing region at a desired operating temperature or within a selected range of temperatures. For example, the byproduct stream may include hydrogen gas, such as 10-30 weight % hydrogen gas, 15-25 weight % hydrogen gas, 20-30 weight % hydrogen gas, at least 10 or 15 weight % hydrogen gas, at least 20 weight % hydrogen gas, etc.
• Purification region40 may include any suitable structure configured to reduce the concentration of at least one component ofoutput stream21. In most applications, hydrogen-rich stream42 will have a greater hydrogen concentration than output stream (or mixed gas stream)34. The hydrogen-rich stream also may have a reduced concentration of one or more non-hydrogen components that were present inoutput stream34 with the hydrogen concentration of the hydrogen-rich stream being more, the same, or less than the output stream. For example, in conventional fuel cell systems, carbon monoxide may damage a fuel cell stack if it is present in even a few parts per million, while other non-hydrogen components that may be present inoutput stream34, such as water, will not damage the stack even if present in much greater concentrations. Therefore, in such an application, the purification region may not increase the overall hydrogen concentration but will reduce the concentration of one or more non-hydrogen components that are harmful, or potentially harmful, to the desired application for the product hydrogen stream.
• Examples of suitable devices forpurification region40 include one or more hydrogen-selective membranes46, chemical carbon monoxide removal assemblies48, and/or pressure swing adsorption (PSA)systems50.Purification region40 may include more than one type of purification device and the devices may have the same or different structures and/or operate by the same or difference mechanism(s).Fuel processing assembly24 may include at least one restrictive orifice and/or other flow restrictor downstream of the purification region(s), such as associated with one or more product hydrogen stream(s), hydrogen-rich stream(s), and/or byproduct stream(s).
• Hydrogen-selective membranes46 are permeable to hydrogen gas, but are at least substantially (if not completely) impermeable to other components ofoutput stream34.Membranes46 may be formed of any hydrogen-permeable material suitable for use in the operating environment and parameters in whichpurification region40 is operated. Examples of suitable materials formembranes46 include palladium and palladium alloys, and especially thin films of such metals and metal alloys. Palladium alloys have proven particularly effective, especially palladium with 35 weight % to 45 weight % copper. A palladium-copper alloy that contains approximately 40 weight % copper has proven particularly effective, although other relative concentrations and components may be used. Another especially effective alloy is palladium with 2 weight % to 10 weight % gold, especially palladium with 5 weight % gold. When palladium and palladium alloys are used, hydrogen-selective membranes46 may sometimes be referred to as “foils.”
• Chemical carbon monoxide removal assemblies48 are devices that chemically react carbon monoxide and/or other undesirable components ofoutput stream34 to form other compositions that are not as potentially harmful. Examples of chemical carbon monoxide removal assemblies include water-gas shift reactors that are configured to produce hydrogen gas and carbon dioxide from water and carbon monoxide, partial oxidation reactors that are configured to convert carbon monoxide and oxygen (usually from air) into carbon dioxide, and methanation reactors that are configured to convert carbon monoxide and hydrogen to methane and water.Fuel processing assembly24 may include more than one type and/or number of chemical removal assemblies48.
• Pressure swing adsorption (PSA) is a chemical process in which gaseous impurities are removed fromoutput stream34 based on the principle that certain gases, under the proper conditions of temperature and pressure, will be adsorbed onto an adsorbent material more strongly than other gases. Typically, the non-hydrogen impurities are adsorbed and removed fromoutput stream34. Adsorption of impurity gases occurs at elevated pressure. When the pressure is reduced, the impurities are desorbed from the adsorbent material, thus regenerating the adsorbent material. Typically, PSA is a cyclic process and requires at least two beds for continuous (as opposed to batch) operation. Examples of suitable adsorbent materials that may be used in adsorbent beds are activated carbon and zeolites.PSA system50 also provides an example of a device for use inpurification region40 in which the byproducts, or removed components, are not directly exhausted from the region as a gas stream concurrently with the purification of the output stream. Instead, these byproduct components are removed when the adsorbent material is regenerated or otherwise removed from the purification region.
• InFIG. 1,purification region40 is shown withinfuel processing assembly24. The purification region may alternatively be separately located downstream from the fuel processing assembly, as is schematically illustrated in dash-dot lines inFIG. 1.Purification region40 also may include portions within and external to the fuel processing assembly.
• Fuel processing assembly24 also may include a temperature modulating assembly in the form of aheating assembly52. The heating assembly may be configured to produce at least one heated exhaust stream (or combustion stream)54 from at least oneheating fuel stream28, typically as combusted in the presence of air. Heated exhaust stream54 is schematically illustrated inFIG. 1 as heating hydrogen-producingregion32.Heating assembly52 may include any suitable structure configured to generate the heated exhaust stream, such as a burner or combustion catalyst in which a fuel is combusted with air to produce the heated exhaust stream. The heating assembly may include an ignitor orignition source58 that is configured to initiate the combustion of fuel. Examples of suitable ignition sources include one or more spark plugs, glow plugs, combustion catalyst, pilot lights, piezoelectric ignitors, spark igniters, hot surface igniters, etc.
• In some embodiments,heating assembly52 may include aburner assembly60 and may be referred to as a combustion-based, or combustion-driven, heating assembly. In a combustion-based heating assembly,heating assembly52 may be configured to receive at least onefuel stream28 and to combust the fuel stream in the presence of air to provide a hot combustion stream54 that may be used to heat at least the hydrogen-producing region of the fuel processing assembly. Air may be delivered to the heating assembly via a variety of mechanisms. For example, an air stream62 may be delivered to the heating assembly as a separate stream, as shown inFIG. 1. Alternatively, or additionally, air stream62 may be delivered to the heating assembly with at least one of the fuel streams28 forheating assembly52 and/or drawn from the environment within which the heating assembly is utilized.
• Combustion stream54 may additionally, or alternatively, be used to heat other portions of the fuel processing assembly and/or fuel cell systems with which the heating assembly is used. Additionally, other configuration and types ofheating assemblies52 may be used. For example,heating assembly52 may be an electrically powered heating assembly that is configured to heat at least hydrogen-producingregion32 offuel processing assembly24 by generating heat using at least one heating element, such as a resistive heating element. In those embodiments,heating assembly52 may not receive and combust a combustible fuel stream to heat the hydrogen-producing region to a suitable hydrogen-producing temperature. Examples of heating assemblies are disclosed in U.S. Pat. No. 7,632,322, the complete disclosure of which is hereby incorporated by reference for all purposes.
• Heating assembly52 may be housed in a common shell or housing with the hydrogen-producing region and/or separation region (as further discussed below). The heating assembly may be separately positioned relative to hydrogen-producingregion32 but in thermal and/or fluid communication with that region to provide the desired heating of at least the hydrogen-producing region.Heating assembly52 may be located partially or completely within the common shell, and/or at least a portion (or all) of the heating assembly may be located external that shell. When the heating assembly is located external the shell, the hot combustion gases fromburner assembly60 may be delivered via suitable heat transfer conduits to one or more components within the shell.
• The heating assembly also may be configured to heatfeedstock delivery system22, the feedstock supply streams, hydrogen-producingregion32, purification (or separation)region40, or any suitable combination of those systems, streams, and regions. Heating of the feedstock supply streams may include vaporizing liquid reactant streams or components of the hydrogen-production fluid used to produce hydrogen gas in the hydrogen-producing region. In that embodiment,fuel processing assembly24 may be described as including avaporization region64. The heating assembly may additionally be configured to heat other components of the hydrogen generation assembly. For example, the heated exhaust stream may be configured to heat a pressure vessel and/or other canister containing the heating fuel and/or the hydrogen-production fluid that forms at least portions offeed stream26 andfuel stream28.
• Heating assembly52 may achieve and/or maintain in hydrogen-producingregion32 any suitable temperatures. Steam reformers typically operate at temperatures in the range of 200° C. and 900° C. However, temperatures outside this range are within the scope of this disclosure. When the carbon-containing feedstock is methanol, the steam reforming reaction will typically operate in a temperature range of approximately 200-500° C. Example subsets of that range include 350-450° C., 375-425° C., and 375-400° C. When the carbon-containing feedstock is a hydrocarbon, ethanol or another alcohol, a temperature range of approximately 400-900° C. will typically be used for the steam reforming reaction. Example subsets of that range include 750-850° C., 725-825° C., 650-750° C., 700-800° C., 700-900° C., 500-800° C., 400-600° C., and 600-800° C. Hydrogen-producingregion32 may include two or more zones, or portions, each of which may be operated at the same or at different temperatures. For example, when the hydrogen-production fluid includes a hydrocarbon, hydrogen-producingregion32 may include two different hydrogen-producing portions, or regions, with one operating at a lower temperature than the other to provide a pre-reforming region. In those embodiments, the fuel processing assembly may also be referred to as including two or more hydrogen-producing regions.
• Fuel stream28 may include any combustible liquid(s) and/or gas(es) that are suitable for being consumed byheating assembly52 to provide the desired heat output. Some fuel streams may be gases when delivered and combusted byheating assembly52, while others may be delivered to the heating assembly as a liquid stream. Examples of suitable heating fuels forfuel streams28 include carbon-containing feedstocks, such as methanol, methane, ethane, ethanol, ethylene, propane, propylene, butane, etc. Additional examples include low molecular weight condensable fuels, such as liquefied petroleum gas, ammonia, lightweight amines, dimethyl ether, and low molecular weight hydrocarbons. Yet other examples include hydrogen and carbon monoxide. In embodiments ofhydrogen generation assembly20 that include a temperature modulating assembly in the form of a cooling assembly instead of a heating assembly (such as may be used when an exothermic hydrogen-generating process—e.g., partial oxidation—is utilized instead of an endothermic process such as steam reforming), the feedstock delivery system may be configured to supply a fuel or coolant stream to the assembly. Any suitable fuel or coolant fluid may be used.
• Fuel processing assembly24 may additionally include a shell orhousing66 in which at least hydrogen-producingregion32 is contained, as shown inFIG. 1. In some embodiments,vaporization region64 and/orpurification region40 may additionally be contained within the shell.Shell66 may enable components of the steam reformer or other fuel processing mechanism to be moved as a unit. The shell also may protect components of the fuel processing assembly from damage by providing a protective enclosure and/or may reduce the heating demand of the fuel processing assembly because components may be heated as a unit.Shell66 may include insulatingmaterial68, such as a solid insulating material, blanket insulating material, and/or an air-filled cavity. The insulating material may be internal the shell, external the shell, or both. When the insulating material is external a shell,fuel processing assembly24 may further include an outer cover orjacket70 external the insulation, as schematically illustrated inFIG. 1. The fuel processing assembly may include a different shell that includes additional components of the fuel processing assembly, such asfeedstock delivery system22 and/or other components.
• One or more components offuel processing assembly24 may either extend beyond the shell or be located external the shell. For example,purification region40 may be locatedexternal shell66, such as being spaced-away from the shell but in fluid communication by suitable fluid-transfer conduits. As another example, a portion of hydrogen-producing region32 (such as portions of one or more reforming catalyst beds) may extend beyond the shell, such as indicated schematically with a dashed line representing an alternative shell configuration inFIG. 1. Examples of suitable hydrogen generation assemblies and its components are disclosed in U.S. Pat. Nos. 5,861,137; 5,997,594; and 6,221,117, the complete disclosures of which are hereby incorporated by reference for all purposes.
• Another example ofhydrogen generation assembly20 is shown inFIG. 2, and is generally indicated at72. Unless specifically excluded, hydrogen generation assembly72 may include one or more components ofhydrogen generation assembly20. Hydrogen-generation assembly72 may include afeedstock delivery system74, avaporization region76, a hydrogen-producingregion78, and aheating assembly80, as shown inFIG. 2. In some embodiments,hydrogen generation assembly20 also may include apurification region82.
• The feedstock delivery system may include any suitable structure configured to deliver one or more feed and/or fuel streams to one or more other components of the hydrogen-generation assembly. For example, feedstock delivery system may include a feedstock tank (or container)84 and apump86. The feedstock tank may contain any suitable hydrogen-production fluid88, such as water and a carbon-containing feedstock (e.g., a methanol/water mixture).Pump86 may have any suitable structure configured to deliver the hydrogen-production fluid, which may be in the form of at least one liquid-containingfeed stream90 that includes water and a carbon-containing feedstock, to vaporizationregion76 and/or hydrogen-producingregion78.
• Vaporization region76 may include any suitable structure configured to receive and vaporize at least a portion of a liquid-containing feed stream, such as liquid-containingfeed stream90. For example,vaporization region76 may include avaporizer92 configured to at least partially transform liquid-containingfeed stream90 into one or more vapor feed streams94. The vapor feed streams may, in some embodiments, include liquid. An example of a suitable vaporizer is a coiled tube vaporizer, such as a coiled stainless steel tube.
• Hydrogen-producingregion78 may include any suitable structure configured to receive one of more feed streams, such as vapor feed stream(s)94 from the vaporization region, to produce one ormore output streams96 containing hydrogen gas as a majority component and other gases. The hydrogen-producing region may produce the output stream via any suitable mechanism(s). For example, hydrogen-producingregion78 may generate output stream(s)96 via a steam reforming reaction. In that example, hydrogen-producingregion78 may include asteam reforming region97 with a reforming catalyst98 configured to facilitate and/or promote the steam reforming reaction. When hydrogen-producingregion78 generates output stream(s)96 via a steam reforming reaction, hydrogen generation assembly72 may be referred to as a “steam reforming hydrogen generation assembly” andoutput stream96 may be referred to as a “reformate stream.”
• Heating assembly80 may include any suitable structure configured to produce at least oneheated exhaust stream99 for heating one or more other components of the hydrogen generation assembly72. For example, the heating assembly may heat the vaporization region to any suitable temperature(s), such as at least a minimum vaporization temperature or the temperature in which at least a portion of the liquid-containing feed stream is vaporized to form the vapor feed stream. Additionally, or alternatively,heating assembly80 may heat the hydrogen-producing region to any suitable temperature(s), such as at least a minimum hydrogen-producing temperature or the temperature in which at least a portion of the vapor feed stream is reacted to produce hydrogen gas to form the output stream. The heating assembly may be in thermal communication with one or more components of the hydrogen generation assembly, such as the vaporization region and/or hydrogen-producing region.
• The heating assembly may include aburner assembly100, at least oneair blower102, and anigniter assembly104, as shown inFIG. 2. The burner assembly may include any suitable structure configured to receive at least oneair stream106 and at least one fuel stream108 and to combust the at least one fuel stream within acombustion region110 to produceheated exhaust stream99. The fuel stream may be provided byfeedstock delivery system74 and/orpurification region82. The combustion region may be contained within an enclosure of the hydrogen generation assembly.Air blower102 may include any suitable structure configured to generate air stream(s)106.Igniter assembly104 may include any suitable structure configured to ignite fuel stream(s)108.
• Purification region82 may include any suitable structure configured to produce at least one hydrogen-rich stream112, which may include a greater hydrogen concentration thanoutput stream96 and/or a reduced concentration of one or more other gases (or impurities) that were present in that output stream. The purification region may produce at least one byproduct stream or fuel stream108, which may be sent toburner assembly100 and used as a fuel stream for that assembly, as shown inFIG. 2.Purification region82 may include aflow restricting orifice111, afilter assembly114, amembrane assembly116, and amethanation reactor assembly118. The filter assembly (such as one or more hot gas filters) may be configured to remove impurities fromoutput stream96 prior to the hydrogen purification membrane assembly.
• Membrane assembly116 may include any suitable structure configured to receive output or mixed gas stream(s)96 that contains hydrogen gas and other gases, and to generate permeate or hydrogen-rich stream(s)112 containing a greater concentration of hydrogen gas and/or a lower concentration of other gases than the mixed gas stream.Membrane assembly116 may incorporate hydrogen-permeable (or hydrogen-selective) membranes that are planar or tubular, and more than one hydrogen-permeable membrane may be incorporated intomembrane assembly116. The permeate stream(s) may be used for any suitable applications, such as for one or more fuel cells. In some embodiments, the membrane assembly may generate a byproduct or fuel stream108 that includes at least a substantial portion of the other gases.Methanation reactor assembly118 may include any suitable structure configured to convert carbon monoxide and hydrogen to methane and water. Althoughpurification region82 is shown to includeflow restricting orifice111,filter assembly114,membrane assembly116, andmethanation reactor assembly118, the purification region may have less than all of those assemblies, and/or may alternatively, or additionally, include one or more other components configured to purifyoutput stream96. For example,purification region82 may includeonly membrane assembly116.
• In some embodiments, hydrogen generation assembly72 may include a shell orhousing120 which may at least partially contain one or more other components of that assembly. For example,shell120 may at least partially containvaporization region76, hydrogen-producingregion78,heating assembly80, and/orpurification region82, as shown inFIG. 2.Shell120 may include one or moreexhaust ports122 configured to discharge at least onecombustion exhaust stream124 produced byheating assembly80.
• Hydrogen generation assembly72 may, in some embodiments, include acontrol system126, which may include any suitable structure configured to control operation of hydrogen generation assembly72. For example,control assembly126 may include acontrol assembly128, at least onevalve130, at least onepressure relief valve132, and one or moretemperature measurement devices134.Control assembly128 may detect temperatures in the hydrogen-producing region and/or purification regions via thetemperature measurement device134, which may include one or more thermocouples and/or other suitable devices. Based on the detected temperatures, the control assembly and/or an operator of the control system may adjust delivery offeed stream90 tovaporization region76 and/or hydrogen-producingregion78 via valve(s)130 and pump(s)86. Valve(s)130 may include a solenoid valve and/or any suitable valve(s). Pressure relief valve(s)132 may be configured to ensure that excess pressure in the system is relieved.
• In some embodiments, hydrogen generation assembly72 may include aheat exchange assembly136, which may include one ormore heat exchangers138 configured to transfer heat from one portion of the hydrogen generation assembly to another portion. For example,heat exchange assembly136 may transfer heat from hydrogen-rich stream112 to feedstream90 to raise the temperature of the feed stream prior to enteringvaporization region76, as well as to cool hydrogen-rich stream112.
• Another example ofhydrogen generation assembly20 is generally indicated at140 inFIG. 3. Unless specifically excluded,hydrogen generation assembly140 may include one or more components of one or more other hydrogen generation assemblies described in this disclosure.Hydrogen generation assembly140 may include a feedstock delivery system or feedassembly142 and afuel processing assembly144 configured to receive at least one feed stream from the feedstock delivery system and produce one or more product hydrogen stream(s), such as a hydrogen gas stream, from the feed stream(s).
• The feedstock delivery system may include any suitable structure configured to deliver one or more feed and/or fuel streams to one or more other components of the hydrogen generation assembly, such asfuel processing assembly144. For example, the feedstock delivery system may include a feedstock tank or feed tank (and/or container)146, afeed conduit148, apump150, and acontrol system152. The feed tank may contain feedstock for one or more feed streams of the fuel processing assembly. For example,feed tank146 may contain any suitable hydrogen-production fluid, such as water and a carbon-containing feedstock (e.g., a methanol/water mixture).
• Feed conduit148 may fluidly connectfeed tank146 withfuel processing assembly144. The feed conduit may include afeed portion154 and abypass portion156. The bypass portion may be configured to prevent overpressurization in the feed conduit, in the fuel processing assembly, and/or in one or more other components ofhydrogen generation assembly140. For example,bypass portion156 may include avalve assembly158, such as a pressure relief valve or a check valve.
• Pump150 may have any suitable structure configured to deliver one or more feed and/or fuel streams to the fuel processing assembly at a plurality of flowrates tofuel processing assembly144 via, for example, feedconduit148. For example, pump150 may be a variable-speed pump (or a pump that includes a variable speed motor) that injects the feed and/or fuel streams into the fuel processing assembly under pressure. The pump may operate at a speed based on a control signal from the control system. For example, pump150 may operate or turn at a higher speed (which results in the pump discharging the feed and/or fuel streams at a higher flowrate) when the control signal increases in magnitude, while the pump may operate or turn at a lower speed (which results in the pump discharging the feed and/or fuel streams at a lower flowrate) when the control signal decreases in magnitude.
• Pressure in the fuel processing assembly (such as in the hydrogen-producing region of the fuel processing assembly) may increase with higher pump flowrates and may decrease with lower pump flowrates. For example, one or more fixed flow restriction devices in the fuel processing assembly may cause a proportional increase in pressure with higher pump flowrates, and a proportional decrease in pressure with lower pump flowrates. Becausefeed conduit148 fluidly connects the feedstock delivery system and the fuel processing assembly, an increase (or decrease) in pressure in the fuel processing assembly may result in an increase (or decrease) in pressure in the feed conduit downstream frompump150.
• Control system152 may include any suitable structure configured to control and/or operatepump150 and/or other controlled devices ofhydrogen generation assembly140. For example,control system152 may include asensor assembly160, acontrol assembly162, andcommunication linkages164.
• The sensor assembly may include any suitable structure configured to detect and/or measure one or more suitable operating variables and/or parameters in the hydrogen generation assembly and/or generate one or more signals based on the detected and/or measured operating variable(s) and/or parameter(s). For example, the sensor assembly may detect mass, volume, flow, temperature, electrical current, pressure, refractive index, thermal conductivity, density, viscosity, optical absorbance, electrical conductivity, and/or other suitable variable(s), and/or parameter(s). In some embodiments, the sensor assembly may detect one or more triggering events. A “triggering event,” as used herein, is a measurable event in which a predetermined threshold value or range of values representative of a predetermined amount of one or more of the components forming one or more streams associated with the hydrogen generation assembly is reached or exceeded.
• For example,sensor assembly160 may include one ormore sensors166 configured to detect pressure, temperature, flowrate, volume, and/or other parameters.Sensors166 may, for example, include at least onefeed sensor168 configured to detect one or more suitable operating variables, parameters, and/or triggering events infeed conduit148. The feed sensor may be configured to detect, for example, pressure in the feed conduit and/or generate one or more signals based on the detected pressure.
• Control assembly162 may be configured to communicate withsensor assembly160 and pump150 (and/or other controlled devices of hydrogen generation assembly140) viacommunication linkages164. For example,control assembly162 may include any suitable structure configured to select a flowrate from the plurality of flowrates ofpump150 based on the detected pressure in the feed conduit, and/or to operate the pump at the selected flowrate.Communication linkages164 may be any suitable wired and/or wireless mechanism for one- or two-way communication between the corresponding devices, such as input signals, command signals, measured parameters, etc.
• Control assembly162 may, for example, include at least oneprocessor170, as shown inFIG. 4. The processor may communicate withsensor assembly160 and pump150 and/or other controlled-devices viacommunication linkages148.Processor170 may have any suitable form, such as a computerized device, software executing on a computer, an embedded processor, programmable logic controller, an analog device (with one or more resistors), and/or functionally equivalent devices. The control assembly may include any suitable software, hardware, and/or firmware. For example,control assembly162 may include memory device(s)172 in which preselected, preprogrammed, and/or user-selected operating parameters may be stored. The memory device may include volatile portion(s), nonvolatile portion(s), and/or both.
• In some embodiments,processor170 may be in the form of asignal conditioner174, which may include any suitable structure configured to condition one or more signals received fromsensor assembly160. The signal conditioner may amplify, filter, convert, invert, range match, isolate, and/or otherwise modify one or more signals received from the sensor assembly such that the conditioned signals are suitable for downstream components. For example,signal conditioner174 may invert one or more signals received fromsensor assembly160. “Invert,” as used herein, refers to one or more of the following: converting a signal with a characteristic having ascending values to a signal with the characteristic having descending values, converting a signal with a characteristic having descending values to a signal with the characteristic having ascending values, converting a signal with a characteristic having a high value to a signal with the characteristic having a low value (or having the highest value to the lowest value), and/or converting a signal with a characteristic having a low value to a signal with the characteristic having a high value (or having the lowest value to the highest value). Characteristics of the signals may include voltage, current, etc. One or more of the converted values may match and/or correspond to values from the original signal, such as converting the highest original value to the lowest original value and/or converting the lowest original value to the highest original value. Alternatively, one or more of the converted values may be different from the original values of the signals.
• In some embodiments,control assembly162 may include auser interface176, as shown inFIG. 4. The user interface may include any suitable structure configured to allow a user to monitor and/or interact with operation ofprocessor170. For example,user interface176 may include adisplay region178, auser input device180, and/or a user-signalingdevice182, as shown inFIG. 4. The display region may include a screen and/or other suitable display mechanism in which information is presented to the user. For example,display region178 may display current values measured by one ormore sensors166, current operating parameters of the hydrogen generation assembly, stored threshold values or ranges, previously measured values, and/or other information regarding the operation and/or performance of the hydrogen generation assembly.
• User input device180 may include any suitable structure configured to receive input from the user and send that input toprocessor170. For example, the user input device may include rotary dials, switches, push-buttons, keypads, keyboards, a mouse, touch screens, etc.User input device180 may, for example, enable a user to specify how signals fromsensor assembly160 will be conditioned, such as whether the signal will be inverted, what the range of values of the inverted signal should be, etc. User-signalingdevice182 may include any suitable structure configured to alert a user when an acceptable threshold level has been exceeded. For example, the user-signaling device may include an alarm, lights, and/or other suitable mechanism(s) for alerting a user.
• In some embodiments,control assembly162 may be configured to only condition signals received fromsensor assembly160 viasignal conditioner168 without additional processing of the signal and/or sending a different signal. In other words, the signal(s) fromsensor assembly160 may be conditioned viasignal conditioner168 and the conditioned signals may be sent to pump150 and/or other controlled device(s) viacommunication linkages164 to operate the pump and/or other controlled devices without additional processing by the control assembly and/or other assemblies.
• The conditioned signal (such as an inverted signal) may be configured, for example, to select a flowrate forpump150 from the plurality of flowrates. When the conditioned signal is configured to select a flowrate for the pump, the control assembly may be described as being configured to select the flowrate based on (or based solely on) the conditioned signal.
• An example of controllingpump150 with a conditioned signal is shown ingraph184 inFIG. 5.Sensor assembly160 may includefeed sensor168 that detects pressure and sends adetection signal186 to controlassembly162 based on the detected pressure. The detection signal may be a voltage signal as shown inFIG. 5, a current signal, and/or other suitable signals that are proportional to the detected pressure. The detection signal(s) may be any suitable voltage(s) and/or current(s), such as 0-5 volts and/or 4-20 milliampere (mA).
• Control assembly162 may condition (such as invert) the detection signal into aconditioned signal188 such that the conditioned signal is configured to select one or more parameters (such as flowrate and/or speed) forpump150 and/or other controlled devices. The conditioned signal(s) may be any suitable voltage(s) and/or current(s), such as 0-5 volts and/or 4-20 mA. The voltages and pressure shown inFIG. 5 are only one example of the various voltages and pressures that may be generated and/or detected bycontrol system152. In other words,control system152 is not limited to operation in the voltages and pressures shown in that figure.
• Another example ofhydrogen generation assembly20 is generally indicated at190 inFIG. 6. Unless specifically excluded,hydrogen generation assembly190 may include one or more components of one or more other hydrogen generation assemblies described in this disclosure.Hydrogen generation assembly190 may include a feedstock delivery system or feedassembly192 and afuel processing assembly194 configured to receive at least one feed stream from the feedstock delivery system and produce one or more product hydrogen stream(s), such as a hydrogen gas stream, from the feed stream(s).
• The feedstock delivery system may include a feedstock tank or feed tank (and/or container)196, afeed conduit198, apump200, and acontrol system202. The feed tank may contain feedstock for one or more feed streams of the fuel processing assembly.Feed conduit198 may fluidly connectfeed tank196 withfuel processing assembly194. The feed conduit may include afeed portion204 and abypass portion206. The bypass portion may be configured to prevent overpressurization inhydrogen generation assembly190. For example,bypass portion206 may include apressure relief valve208.
• Pump200 may have any suitable structure configured to deliver one or more feed and/or fuel streams to the fuel processing assembly at a plurality of flowrates tofuel processing assembly194 via, for example, feedconduit198. For example, pump200 may be a variable-speed pump (or a pump that includes a variable speed motor) that injects the feed and/or fuel streams into the fuel processing assembly under pressure. The pump may operate at a speed based on a control signal from the control system.
• Control system202 may include any suitable structure configured to control and/or operatepump200 and/or other controlled devices ofhydrogen generation assembly190. For example,control system202 may include at least onepressure transducer210, acontrol assembly212, andcommunication linkages214.Pressure transducer210 may be configured to detect pressure infeed conduit198. Althoughpressure transducer210 is shown to be adjacent to pump200 and/orbypass portion206, the pressure transducer may be positioned in any suitable portions along the feed portion.
• Control assembly212 may include apower supply assembly216 and asignal conditioner assembly218. The power supply assembly may include any suitable structure configured to provide suitable power to the signal conditioner assembly. For example, the power supply assembly may include one or more batteries, one or more solar panels, one or more connectors for connecting to a DC or AC power source, etc. In some embodiments,power supply assembly216 may include a DC power supply, which may provide the same voltage as is required to operatepump200 and/orpressure transducer210.
• Signal conditioner assembly218 may include any suitable structure configured to condition one or more signals received frompressure transducer210 such that one or more of the conditioned signals may be used to operatepump200. For example,signal conditioner assembly218 may invert the pressure signals (or transducer signals) received from the pressure transducer and relay the inverted signals viacommunication linkages214 to pump200. The inverted signals may be configured to select a speed and/or flowrate forpump200 among the plurality of speeds and/or flowrates for the pump. When the inverted signals are used to control the pump's speed, the signals may be referred to as “speed control signals.”
• An example of a purge assembly of the hydrogen generation assemblies described in the present disclosure is shown inFIG. 7 and is generally indicated at220. The purge assembly may include any suitable structure configured to purge one or more other portions of a hydrogen generation assembly.Purge assembly220 may be configured to purge one or more gases from reactor(s), purifier(s), fuel processing assembly(ies), and/or other component(s) and/or device(s) of hydrogen generation assemblies of the present disclosure and/or other hydrogen generation assemblies. For example,purge assembly220 may include apressurized gas assembly222, apurge conduit224, and avalve assembly226. Purgeconduit224 may be configured to fluidly connect the pressurized gas assembly and one or more other portions of the hydrogen generation assembly.
• Pressurized gas assembly222 may include any suitable structure configured to connect to and/or receive at least one gas supply assembly228. For example,pressurized gas assembly222 may include any suitable connectors, piping, valves, and/or other components configured to connect to and/or receive gas supply assembly228. The gas supply assembly may include one or more containers of pressurized gas (such as one or more cartridges and/or cylinders) and/or one or more tanks of pressurized gas. The gas supply assembly may include any suitable pressurized gas configured to purge one or more other components of the hydrogen generation assemblies described in the present disclosure. For example, gas supply assembly may include compressed carbon dioxide or compressed nitrogen.
• Purgeconduit224 may be configured to fluidly connect the pressurized gas assembly and one or more other portions of the hydrogen generation assembly, such as the fuel processing assembly. The purge conduit may include any suitable connectors, piping, valves, and/or other components to provide for the fluid connection between the above assemblies.
• Valve assembly226 may include any suitable structure configured to manage flow of the pressurized gas throughpurge conduit224 frompressurized gas assembly222 to one or more other portions of the hydrogen generation assembly. For example,valve assembly226 may be configured to allow at least one pressurized gas to flow through the purge conduit from the pressurized gas assembly to one or more other portions of the hydrogen generation assembly and/or to prevent the at least one pressurized gas to flow through the purge conduit from the pressurized gas assembly to one or more other portions of the hydrogen generation assembly. The valve assembly may be configured to allow or prevent flow based on one or more detected variable(s), parameter(s) and/or triggering event(s). For example, the valve assembly may be configured to allow flow of at least one pressurized gas from the pressurized gas assembly to one or more other portions of the hydrogen generation assembly when power to one or more portions of the hydrogen generation assembly is interrupted.
• In some embodiments, acontrol system230 may control one or more valves ofvalve assembly226.Control system230 may also control one or more other components of the hydrogen generation assembly, or may be dedicated to controllingonly purge assembly220. In some embodiments,valve assembly226 may be configured to manage flow in the purge conduit independent ofcontrol system230 and/or any control system of the hydrogen generation assembly. In other words,valve assembly226 may be configured to selectively allow and prevent flow without direction fromcontrol system230 and/or any control system of the hydrogen generation assembly.
• The purge assembly may be located within enclosure orshell66, external to the shell, or partially within the shell and partially external the shell. In some embodiments, at least a portion of the fuel processing assembly may be contained within an enclosure and at least a portion of the purge assembly may be contained within the enclosure, as shown inFIG. 1.
• Purge assembly220 may be connected to any suitable other component(s) of the hydrogen generation assembly. For example, as shown inFIG. 2,purge assembly220 may be connected to the feed conduit either upstream of heat exchange assembly136 (such as shown via purge conduit224), and/or downstream of the heat exchange assembly (such as shown via a purge conduit225). In some embodiments, the feed conduit of the hydrogen generation assembly may include acheck valve232 to prevent backflow of the pressurized gas into the feedstock delivery system, such as when the pump does not prevent backflow. The pressurized gas from the purge assembly may exit the hydrogen generation assembly at any suitable portions, such as the burner and/or the product hydrogen line.
• Another example ofpurge assembly220 is shown inFIG. 8 and is generally indicated at232.Purge assembly232 may include apressurized gas assembly234, apurge conduit236, and avalve assembly238. The pressurized gas assembly may include any suitable structure configured to receive at least onepressurized gas container240 having at least one pressurized gas. Purgeconduit236 may include any suitable structure configured to fluidly connectpressurized gas assembly234 and one or more other portions of the hydrogen generation assembly.
• Valve assembly238 may include any suitable structure configured to manage flow of the at least one pressurized gas through the purge conduit from the pressurized gas assembly to one or more other portions of the hydrogen generation assembly. For example,valve assembly238 may include amanual valve240 and a solenoid valve (or purge solenoid valve)242, as shown inFIG. 8. The manual valve may be closed to isolate the pressurized gas assembly from one or more other portions of the hydrogen generation assembly, such as when installing or connecting a compressed or pressurized gas canister to the pressurized gas assembly.Manual valve240 may then be opened to allow the solenoid valve to manage flow of the gas through the purge conduit from the pressurized gas assembly to one or more other portions of the hydrogen generation assembly.Manual valve240 may sometimes be referred to as a “manual isolation valve.”
• Solenoid valve242 may include at least one solenoid orpurge solenoid244 and at one valve orpurge valve246. The valve may be configured to move among a plurality of positions, including between a closed position and an open position. In the closed position, the pressurized gas assembly is isolated from one or more other portions of the hydrogen generation assembly and the pressurized gas does not flow through the purge conduit from the pressurized gas assembly. In the open position, the pressurized gas assembly is in fluid communication with one or more other portions of the hydrogen generation assembly and pressurized gas is allowed to flow through the purge conduit from the pressurized gas assembly.Solenoid244 may be configured to movevalve226 between the open and closed positions based on one or more detected variable(s), parameter(s) and/or triggering event(s).Solenoid valve242 may, for example, be configured to allow flow of at least one pressurized gas from the pressurized gas assembly to one or more other portions of the hydrogen generation assembly when power to the solenoid and/or one or more portions of the hydrogen generation assembly is interrupted, such as when power to the fuel processing assembly is interrupted.
• For example,valve246 may be configured to be in the open position without power to solenoid244 (may also be referred to as “normally open”), such as via urging of one or more bias elements or springs (not shown). Additionally,valve246 may be configured to be in the closed position with power to solenoid244 (which may move the valve to the closed position against urging of the bias element(s)). Thus, a loss of electrical power to one or more portions of the hydrogen generation assembly (and/or a loss of electrical power to solenoid244) may causevalve246 to automatically move from the closed position to the open position. In other words,valve246 ofsolenoid valve242 may be configured to be in the closed position when there is power to the solenoid and/or one or more portions of the hydrogen generation assembly (such as the fuel processing assembly), and may automatically move to the open position when power to the solenoid and/or one or more portions of the hydrogen generation assembly is interrupted.
• In some embodiments,solenoid valve242 may be controlled by acontrol system248. For example,control system248 may be configured to send a control signal tosolenoid244 and the solenoid may be configured to movevalve246 to the closed position when the control signal is received. Additionally,valve246 may be configured to automatically move to the open position when the solenoid does not receive a control signal from the control system.Control system248 may control one or more other components of the hydrogen generation assembly or may be separate from any control system. The solenoid valve may, in some embodiments, be controlled by both the control system and whether power is supplied to the solenoid.
• In some embodiments,purge assembly220 may include a flow-restriction orifice250, which may be configured to reduce or limit flow rate of the pressurized gas discharged from the pressurized gas assembly. For example, when the pressurized gas is nitrogen, the flow-restriction orifice may reduce or limit flow rate of the nitrogen gas to avoid overpressure in one or more other components of the hydrogen generation assembly, such as in the reformer and/or purifier. However, when the pressurized gas is liquefied compressed gas, such as carbon dioxide, the purge assembly may not include the flow-restriction orifice.
• The purge assemblies of the present disclosure may be used as part of (or in) any suitable hydrogen generation assembly, such as a hydrogen generation assembly with a reformer but without a hydrogen purifier, a hydrogen generation assembly with a hydrogen purifier but without a reformer, a hydrogen generation assembly with a methanol/water reformer, a natural gas reformer, a LPG reformer, etc.
• Another example ofhydrogen generation assembly20 is generally indicated at252 inFIG. 9. Unless specifically excluded,hydrogen generation assembly252 may include one or more components of one or more other hydrogen generation assemblies described in this disclosure.Hydrogen generation assembly252 may include an enclosure orshell254, a hydrogen-producingregion256, a heating assembly258, and anexhaust management assembly260. The enclosure or shell may include any suitable structure configured to at least partially contain one or more other components ofhydrogen generation assembly252 and/or provide insulation (such as thermal insulation) for those component(s). The enclosure may define an insulated zone or insulatedhot zone261 for the components within the enclosure.Enclosure254 may include at least oneexhaust port262 configured to exhaust gases within the enclosure to the environment and/or to an exhaust collection system.
• Hydrogen-producingregion256 may be partially or fully contained within the enclosure. The hydrogen-producing region may receive one ormore feed streams264 and produce anoutput stream266 containing hydrogen gas via any suitable hydrogen-producing mechanism(s), such as steam reforming, autothermal reforming, etc. The output stream may include hydrogen gas as at least a majority component and may include additional gases. Whenhydrogen generation assembly252 is a steam reforming hydrogen generation assembly, then the hydrogen-producing region may be referred to as being configured to produce, via a steam reforming reaction, areformate stream266.
• In some embodiments,hydrogen generation assembly252 may include apurification region268, which may include any suitable structure configured to produce at least one hydrogen-rich (or permeate)stream270 from output (or reformate)stream266 and at least one byproduct stream272 (which may contain no or some hydrogen gas). For example, the purification region may include one or more hydrogen-selective membranes274. The hydrogen-selective membrane(s) may be configured to produce at least part of the permeate stream from the portion of the reformate stream that passes through the hydrogen-selective membrane(s), and to produce at least part of the byproduct stream from the portion of the reformate stream that does not pass through the hydrogen-selective membrane(s). In some embodiments,hydrogen generation assembly252 may include avaporization region276, which may include any suitable structure configured to vaporize the feed stream(s) containing one or more liquid(s).
• Heating assembly258 may be configured to receive at least one air stream278 and at least onefuel stream280 and to combust the fuel stream(s) within acombustion region282 contained withinenclosure254.Fuel stream280 may be produced from the hydrogen-producing region (and/or the purification region), and/or may be produced independent of the hydrogen generation assembly. The combustion of the fuel stream(s) may produce one or more heated exhaust streams284. The heated exhaust stream(s) may heat, for example, hydrogen-producingregion256, such as to at least a minimum hydrogen-producing temperature. Additionally, the heated exhaust stream(s) may heatvaporization region276, such as to at least a minimum vaporization temperature.
• Exhaust management assembly260 may include any suitable structure configured to manage exhaust streams inenclosure254, such as heated exhaust streams284. For example, the exhaust management assembly may include asensor assembly286, adamper assembly288, and acontrol assembly290, as shown inFIG. 9.
• Sensor assembly286 may include any suitable structure configured to detect and/or measure one or more suitable operating variables and/or parameters in the hydrogen generation assembly and/or generate one or more signals based on the detected and/or measured operating variable(s) and/or parameter(s). For example, the sensor assembly may detect mass, volume, flow, temperature, electrical current, pressure, refractive index, thermal conductivity, density, viscosity, optical absorbance, electrical conductivity, and/or other suitable variable(s), and/or parameter(s). In some embodiments, the sensor assembly may detect one or more triggering events.
• For example,sensor assembly286 may include one ormore sensors292 configured to detect pressure, temperature, flowrate, volume, and/or other parameters in any suitable portion(s) of the hydrogen generation assembly.Sensors292 may, for example, include at least one hydrogen-producingregion sensor294 configured to detect one or more suitable operating variables, parameters, and/or triggering events in hydrogen-producingregion256. The hydrogen-producing region sensor may be configured to detect, for example, temperature in the hydrogen-producing region and/or generate one or more signals based on the detected temperature in the hydrogen-producing region.
• Additionally,sensors292 may include at least onepurification region sensor296 configured to detect one or more suitable operating variables, parameters, and/or triggering events inpurification region268. The purification region sensor may be configured to detect, for example, temperature in the purification region and/or generate one or more signals based on the detected temperature in the purification region.
• Damper assembly288 may include any suitable structure configured to manage flow, such as the flow of exhaust gases (or heated exhaust stream(s)284), throughexhaust port262. For example,damper assembly288 may include at least onedamper298 and at least oneactuator300. The damper may be moveably connected to exhaustport262. For example,damper298 may be slidably, pivotably, and/or rotatably connected to the exhaust port.
• Additionally, the damper may be configured to move among a plurality of positions. Those positions may include, for example, a fullyopen position302, aclosed position304, and a plurality of intermediateopen positions306 between the fully open and closed positions, as shown inFIGS. 10-12. In the fully open position,damper298 may allow one or more exhaust streams307 (such as heated exhaust stream(s)284 and/or other exhaust gases in the enclosure) to flow throughexhaust port262. In the closed position,damper298 may block the exhaust port and prevent exhaust stream(s) from flowing through the exhaust port. The intermediate open positions may allow the exhaust stream(s) to flow throughexhaust port262 at slower rate(s) than when the damper is in the fully open position. During operation, the temperature in the hydrogen-producing region may decrease when the exhaust stream(s) are restricted by the damper.
• Damper298 may include any suitable structure. For example,damper298 may be a gate-type damper with one or more plates that slide across the exhaust port, such as shown inFIGS. 10-12. Additionally,damper298 may be a flapper-type damper, such as shown inFIG. 9. The flapper-type damper may, for example, include full circle or half-circle inserts that pivot to open or close the exhaust.Actuator300 may include any suitable structure configured to movedamper298 among the plurality of positions. In some embodiments, the actuator may move the damper incrementally between the fully open and closed positions. Althoughdamper assembly288 is shown to include a single damper and a single actuator, the damper assembly may include two or more dampers and/or two or more actuators.
• Control assembly290 may include any suitable structure configured to controldamper assembly288 based, at least in part, on input(s) fromsensor assembly286, such as based, at least in part, on detected and/or measured operating variable(s) and/or parameter(s) by the sensor assembly.Control assembly290 may receive input(s) only fromsensor assembly286 or the control assembly may receive input(s) from other sensor assemblies of the hydrogen generation assembly.Control assembly290 may control only damper assembly, or the control assembly may control one or more other components of the hydrogen generation assembly.
• Control assembly290 may, for example, be configured to movedamper298, such as viaactuator300, between the fully open and closed positions based, at least in part, on the detected temperature in the hydrogen-producing region and/or the purification region. Whencontrol assembly290 receives inputs from two or more sensors, the control assembly may select the input with a higher value, may select the input with a lower value, may calculate an average of the input values, may calculate a median of the input values, and/or perform other suitable calculation(s). For example,control assembly290 may be configured to move the damper toward (or incrementally toward) the closed position when detected temperature in the hydrogen-producing and/or purification regions are above a predetermined maximum temperature, and/or to move the damper toward (or incrementally toward) the fully open position when the detected temperature in the hydrogen-producing and/or purification regions are below a predetermined minimum temperature. The predetermined maximum and minimum temperatures may be any suitable maximum and minimum temperatures. For example, the maximum and minimum temperatures may be set based on a desired range of temperatures for operating the vaporization, hydrogen-producing, and/or purification regions.
• Another example ofhydrogen generation assembly20 is generally indicated at308 inFIG. 13. Unless specifically excluded,hydrogen generation assembly308 may include one or more components of one or more other hydrogen generation assemblies described in this disclosure. The hydrogen generation assembly may provide or supply hydrogen to one or morehydrogen consuming devices310, such as a fuel cell, hydrogen furnace, etc.Hydrogen generation assembly308 may, for example, include afuel processing assembly312 and a producthydrogen management system314.
• Fuel processing assembly312 may include any suitable structure configured to generate one or more product hydrogen streams316 (such as one or more hydrogen gas streams) from one ormore feed streams318 via one or more suitable mechanisms, such as steam reforming, autothermal reforming, electrolysis, thermolysis, partial oxidation, plasma reforming, photocatalytic water splitting, sulfur-iodine cycle, etc. For example,fuel processing assembly312 may include one or morehydrogen generator reactors320, such as reformer(s), electrolyzer(s), etc. Feed stream(s)318 may be delivered to the fuel processing assembly via one ormore feed conduits317 from one or more feedstock delivery systems (not shown).
• Fuel processing assembly312 may be configured to be operable among a plurality of modes, such as a run mode and a standby mode. In the run mode, the fuel processing assembly may produce or generate the product hydrogen stream(s) from the feed stream(s). For example, in the run mode, the feedstock delivery system may deliver the feed stream to the fuel processing assembly and/or may perform other operation(s). Additionally, in the run mode, the fuel processing assembly may receive the feed stream, may combust the fuel stream via the heating assembly, may vaporize the feed stream via the vaporization region, may generate the output stream via the hydrogen producing region, may generate the product hydrogen stream and the byproduct stream via the purification region, and/or may perform other operations.
• In the standby mode,fuel processing assembly312 may not produce the product hydrogen stream(s) from the feed stream(s). For example, in the standby mode, the feedstock delivery system may not deliver the feed stream to the fuel processing assembly and/or may not perform other operation(s). Additionally, in the standby mode, the fuel processing assembly may not receive the feed stream, may not combust the fuel stream via the heating assembly, may not vaporize the feed stream via the vaporization region, may not generate the output stream via the hydrogen producing region, may not generate the product hydrogen stream and the byproduct stream via the purification region, and/or may not perform other operations. The standby mode may include when the fuel processing assembly is powered down or when there is no power to the fuel processing assembly.
• In some embodiments, the plurality of modes may include one or more reduced output modes. For example,fuel processing assembly312 may produce or generate product hydrogen stream(s)316 at a first output rate when in the run mode (such as at a maximum output rate or normal output rate), and produce or generate the product hydrogen stream(s) at second, third, fourth, or more rates that are lower (or higher) than the first rate when in the reduced output mode (such as at a minimum output rate).
• Producthydrogen management system314 may include any suitable structure configured to manage product hydrogen generated byfuel processing assembly312. Additionally, the product hydrogen management system may include any suitable structure configured to interact withfuel processing assembly312 to maintain any suitable amount of product hydrogen available for hydrogen consuming device(s)310. For example, producthydrogen management system314 may include aproduct conduit322, abuffer tank324, abuffer tank conduit325, asensor assembly326, and acontrol assembly328.
• Product conduit322 may be configured to fluidly connectfuel processing assembly312 withbuffer tank324.Buffer tank324 may be configured to receiveproduct hydrogen stream316 viaproduct conduit322, to retain a predetermined amount or volume of the product hydrogen stream, and/or to provide the product hydrogen stream to one or morehydrogen consuming devices310. In some embodiments, the buffer tank may be a lower-pressure buffer tank. The buffer tank may be any suitable size based on one or more factors, such as expected or actual hydrogen consumption by the hydrogen consuming device(s), cycling characteristics of the hydrogen generator reactor, fuel processing assembly, etc.
• In some embodiments,buffer tank324 may be sized to provide enough hydrogen for a minimum amount of time of operation of the hydrogen consuming device(s) and/or for a minimum amount of time of operation for the fuel processing assembly, such as a minimum amount of time of operation for the vaporization region, hydrogen-producing region, and/or purification region. For example, the buffer tank may be sized for two, five, ten, or more minutes of operation of the fuel processing assembly.Buffer tank conduit325 may be configured to fluidly connectbuffer tank324 with hydrogen consuming device(s)310.
• Sensor assembly326 may include any suitable structure configured to detect and/or measure one or more suitable operating variables and/or parameters in the buffer tank and/or generate one or more signals based on the detected and/or measured operating variable(s) and/or parameter(s). For example, the sensor assembly may detect mass, volume, flow, temperature, electrical current, pressure, refractive index, thermal conductivity, density, viscosity, optical absorbance, electrical conductivity, and/or other suitable variable(s), and/or parameter(s). In some embodiments, the sensor assembly may detect one or more triggering events.
• For example,sensor assembly326 may include one ormore sensors330 configured to detect pressure, temperature, flowrate, volume, and/or other parameters.Sensors330 may, for example, include at least onebuffer tank sensor332 configured to detect one or more suitable operating variables, parameters, and/or triggering events in the buffer tank. The buffer tank sensor may be configured to detect, for example, pressure in the buffer tank and/or generate one or more signals based on the detected pressure. For example, unless product hydrogen is being withdrawn from the buffer tank at a flow rate that is equal to, or greater than, the incoming flow rate into the buffer tank, the pressure of the buffer tank may increase and the tank sensor may detect the increase of pressure in the buffer tank.
• Control assembly328 may include any suitable structure configured to controlfuel processing assembly312 based, at least in part, on input(s) fromsensor assembly326, such as based, at least in part, on detected and/or measured operating variable(s) and/or parameter(s) by the sensor assembly.Control assembly328 may receive input(s) only fromsensor assembly326 or the control assembly may receive input(s) from other sensor assemblies of the hydrogen generation assembly.Control assembly328 may control only the fuel processing assembly, or the control assembly may control one or more other components of the hydrogen generation assembly. The control assembly may communicate with the sensor assembly, the fuel processing assembly, and/or a product valve assembly (further described below) viacommunication linkages333.Communication linkages333 may be any suitable wired and/or wireless mechanism for one- or two-way communication between the corresponding devices, such as input signals, command signals, measured parameters, etc.
• Control assembly328 may, for example, be configured to operatefuel processing assembly312 between the run and standby modes based, at least in part, on the detected pressure inbuffer tank324. For example,control assembly328 may be configured to operate the fuel processing assembly in the standby mode when the detected pressure in the buffer tank is above a predetermined maximum pressure, and/or to operate the fuel processing assembly in the run mode when the detected pressure in the buffer tank is below a predetermined minimum pressure.
• The predetermined maximum and minimum pressures may be any suitable maximum and minimum pressures. Those predetermined pressures may be independently set, or set without regard to other predetermined pressure(s) and/or other predetermined variable(s). For example, the predetermined maximum pressure may be set based on the operating pressure range of the fuel processing assembly, such as to prevent overpressure in the fuel processing assembly because of back pressure from the product hydrogen management system. Additionally, the predetermined minimum pressure may be set based on the pressure required by the hydrogen consuming device(s). Alternatively,control assembly328 may operate the fuel processing assembly to operate in the run mode within a predetermined range of pressure differentials (such as between the fuel processing assembly and the buffer tank and/or between the buffer tank and the hydrogen consuming device(s)), and in the standby mode when outside the predetermined range of pressure differentials.
• In some embodiments, producthydrogen management system314 may include aproduct valve assembly334, which may include any suitable structure configured to manage and/or direct flow inproduct conduit322. For example, the product valve assembly may allow the product hydrogen stream to flow from the fuel processing assembly to the buffer tank, as indicated at335. Additionally,product valve assembly334 may be configured to ventproduct hydrogen stream316 fromfuel processing assembly312, as indicated at337. The vented product hydrogen stream may be discharged to atmosphere and/or to a vented product hydrogen management system (not shown).
• Product valve assembly334 may, for example, include one ormore valves336 that are configured to operate between a flow position in which the product hydrogen stream from the fuel processing assembly flows through the product conduit and into the buffer tank, and a vent position in which the product hydrogen stream from the fuel processing assembly is vented. Valve(s)336 may be positioned along any suitable portion(s) of the product conduit prior to the buffer tank.
• Control assembly328 may be configured to operate the product valve assembly based on, for example, input(s) from sensor assembly. For example, the control assembly may direct or control the product valve assembly (and/or valve(s)336) to vent the product hydrogen stream from the fuel processing assembly when the fuel processing assembly is in the standby mode. Additionally,control assembly328 may direct or control product valve assembly334 (and/or valve(s)336) to allow the product hydrogen stream to flow from the fuel processing assembly to the buffer tank whenfuel processing assembly312 is in the run mode and/or reduced output mode(s).
• Another example ofhydrogen generation assembly20 is generally indicated at338 inFIG. 14. Unless specifically excluded,hydrogen generation assembly338 may include one or more components of one or more other hydrogen generation assemblies described in this disclosure. The hydrogen generation assembly may provide or supply hydrogen to one or morehydrogen consuming devices340, such as a fuel cell, hydrogen furnace, etc.Hydrogen generation assembly338 may, for example, include afuel processing assembly342 and a producthydrogen management system344.Fuel processing assembly342 may include any suitable structure configured to generate one or more product hydrogen streams346 (such as one or more hydrogen gas streams) from one ormore feed streams348 via one or more suitable mechanisms.
• Producthydrogen management system344 may include any suitable structure configured to manage product hydrogen generated byfuel processing assembly342. Additionally, the product hydrogen management system may include any suitable structure configured to interact withfuel processing assembly342 to maintain any suitable amount of product hydrogen available for hydrogen consuming device(s)340. For example, producthydrogen management system344 may include aproduct conduit349, abuffer tank352, abuffer tank conduit353, a buffertank sensor assembly354, aproduct valve assembly355, and acontrol assembly356.
• Product conduit349 may be configured to fluidly connectfuel processing assembly342 withbuffer tank352. The product conduit may include any suitable number of valves, such as check valve(s) (such as check valve350), control valve(s), and/or other suitable valves.Check valve350 may prevent backflow from the buffer tank toward the fuel processing assembly. The check valve may open at any suitable pressures, such as 1 psi or less.Buffer tank352 may be configured to receiveproduct hydrogen stream346 viaproduct conduit349, to retain a predetermined amount or volume of the product hydrogen stream, and/or to provide the product hydrogen stream to one or morehydrogen consuming devices340.
• Buffer tank conduit353 may be configured to fluidly connectbuffer tank352 and hydrogen consuming device(s)340. The buffer tank conduit may include any suitable number of valves, such as check valve(s), control valve(s), and/or other suitable valve(s). For example, the buffer tank conduit may include one ormore control valves351.Control valve351 may allow isolation of the buffer tank and/or other components of the hydrogen generation assembly. The control valve may, for example, be controlled bycontrol assembly356 and/or other control assembly(ies).
• Tank sensor assembly354 may include any suitable structure configured to detect and/or measure one or more suitable operating variables and/or parameters in the buffer tank and/or generate one or more signals based on the detected and/or measured operating variable(s) and/or parameter(s). For example, the buffer tank sensor assembly may detect mass, volume, flow, temperature, electrical current, pressure, refractive index, thermal conductivity, density, viscosity, optical absorbance, electrical conductivity, and/or other suitable variable(s), and/or parameter(s). In some embodiments, the buffer tank sensor assembly may detect one or more triggering events. For example, buffertank sensor assembly354 may include one ormore tank sensors358 configured to detect pressure, temperature, flowrate, volume, and/or other parameters.Buffer tank sensors358 may, for example, be configured to detect pressure in the buffer tank and/or generate one or more signals based on the detected pressure.
• Product valve assembly355 may include any suitable structure configured to manage and/or direct flow inproduct conduit349. For example, the product valve assembly may allow the product hydrogen stream to flow from the fuel processing assembly to the buffer tank, as indicated at359. Additionally,product valve assembly355 may be configured to ventproduct hydrogen stream346 fromfuel processing assembly342, as indicated at361. The vented product hydrogen stream may be discharged to atmosphere and/or to a vented product hydrogen management system (not shown) including discharging vented product hydrogen back to the fuel processing assembly.
• Product valve assembly355 may, for example, include a three-way solenoid valve360. The three-way solenoid valve may include asolenoid362 and a three-way valve364. The three-way valve may be configured to move between a plurality of positions. For example, three-way valve364 may be configured to move between aflow position363 and avent position365, as shown inFIGS. 15-16. In the flow position, the product hydrogen stream is allowed to flow from the fuel processing assembly to the buffer tank, as indicated at359. In the vent position, the product hydrogen stream from the fuel processing assembly is vented, as indicated at361. Additionally, the three-way valve may be configured to isolate the buffer tank from the product hydrogen stream when the valve is in the vent position.Solenoid362 may be configured to movevalve364 between the flow and vent positions based on input(s) received fromcontrol assembly356 and/or other control assembly(ies).
• Control assembly356 may include any suitable structure configured to controlfuel processing assembly342 and/orproduct valve assembly355 based, at least in part, on input(s) from buffertank sensor assembly354, such as based, at least in part, on detected and/or measured operating variable(s) and/or parameter(s) by the buffer tank sensor assembly.Control assembly356 may receive input(s) only from buffertank sensor assembly354 and/or the control assembly may receive input(s) from other sensor assemblies of the hydrogen generation assembly. Additionally,control assembly356 may control only the fuel processing assembly, only the product valve assembly, only both the fuel processing assembly and the product valve assembly, or the fuel processing assembly, product valve assembly and/or one or more other components of the hydrogen generation assembly.Control assembly356 may communicate with the fuel processing assembly, the buffer tank sensor assembly, and the product valve assembly viacommunication linkages357.Communication linkages357 may be any suitable wired and/or wireless mechanism for one- or two-way communication between the corresponding devices, such as input signals, command signals, measured parameters, etc.
• Control assembly356 may, for example, be configured to operatefuel processing assembly342 among or between the run and standby modes (and/or reduced output mode(s)) based, at least in part, on the detected pressure inbuffer tank352. For example,control assembly356 may be configured to operate the fuel processing assembly in the standby mode when the detected pressure in the buffer tank is above a predetermined maximum pressure, to operate the fuel processing assembly in one or more reduced output mode(s) when the detected pressure in the buffer tank is below a predetermined maximum pressure and/or above a predetermined operating pressure, and/or to operate the fuel processing assembly in the run mode when the detected pressure in the buffer tank is below a predetermined operating pressure and/or predetermined minimum pressure. The predetermined maximum and minimum pressures and/or predetermined operating pressure(s) may be any suitable pressures. For example, the one or more of the above pressures may be independently set based on a desired range of pressures for the fuel processing assembly, product hydrogen in the buffer tank, and/or the pressure requirements of the hydrogen consuming device(s). Alternatively,control assembly356 may operate the fuel processing assembly to operate in the run mode within a predetermined range of pressure differentials (such as between the fuel processing assembly and the buffer tank), and in the reduced output and/or standby mode when outside the predetermined range of pressure differentials.
• Additionally,control assembly356 may be configured to operate the product valve assembly based on, for example, input(s) from sensor assembly. For example, the control assembly may direct orcontrol solenoid362 to move three-way valve364 to the vent position when the fuel processing assembly is in the standby mode. Additionally,control assembly356 may direct or control the solenoid to move three-way valve364 to the flow position whenfuel processing assembly342 is in the run mode.
• Control assembly356 may, for example, include acontroller366, aswitching device368, and apower supply370.Controller366 may have any suitable form, such as a computerized device, software executing on a computer, an embedded processor, programmable logic controller, an analog device, and/or functionally equivalent devices. Additionally, the controller may include any suitable software, hardware, and/or firmware.
• Switching device368 may include any suitable structure configured to allowcontroller366 to controlsolenoid362. For example, the switching device may include a solid-state relay372. The solid-state relay may allowcontroller366 to controlsolenoid362 viapower supply370. For example, whensolenoid362 is controlled with 24 volts, the solid-state relay may allowcontroller366 to use a voltage signal less than 24 volts (such as 5 volts) to controlsolenoid362.Power supply370 may include any suitable structure configured to provide power sufficient to controlsolenoid362. For example,power supply370 may include one or more batteries, one or more solar panels, etc. In some embodiments, the power supply may include one or more electrical outlet connectors and one or more rectifiers (not shown). Although the solenoid and controller are described to operate at certain voltages, the solenoid and controller may operate at any suitable voltages.
• Another example ofhydrogen generation assembly20 is generally indicated at374 inFIG. 17. Unless specifically excluded,hydrogen generation assembly374 may include one or more components of one or more other hydrogen generation assemblies described in this disclosure. The hydrogen generation assembly may provide or supply hydrogen to one or morehydrogen consuming devices376, such as a fuel cell, hydrogen furnace, etc.Hydrogen generation assembly374 may, for example, include afuel processing assembly378 and a producthydrogen management system380.Fuel processing assembly378 may include any suitable structure configured to generate one or more product hydrogen streams382 (such as one or more hydrogen gas streams) from one ormore feed streams384 via one or more suitable mechanisms.
• Producthydrogen management system380 may include any suitable structure configured to manage product hydrogen generated byfuel processing assembly382 and/or interact withfuel processing assembly382 to maintain any suitable amount of product hydrogen available for hydrogen consuming device(s)376. For example, producthydrogen management system380 may include aproduct conduit386, abuffer tank388, a buffer tank conduit389, atank sensor assembly390, aproduct valve assembly392, and acontrol assembly394.
• Product conduit386 may be configured to fluidly connectfuel processing assembly378 withbuffer tank388. The product conduit may include a flow portion orleg395 and a vent portion orleg396. Additionally,product conduit386 may include any suitable number of valves, such as check valve(s) (such as check valve397), control valve(s), and/or other suitable valve(s).Buffer tank388 may be configured to receiveproduct hydrogen stream382 viaproduct conduit386, to retain predetermined amount(s) or volume(s) of the product hydrogen stream, and/or to provide the product hydrogen stream to one or morehydrogen consuming devices376.
• Buffer tank conduit389 may be configured to fluidly connectbuffer tank388 with hydrogen consuming device(s)376. The buffer tank conduit may include any suitable number of valves, such as check valve(s), control valve(s), and/or other suitable valve(s). For example, the buffer tank conduit may include one ormore control valves398.Control valve398 may allow isolation of the buffer tank and/or other components of the hydrogen generation assembly. The control valve may, for example, be controlled bycontrol assembly394 and/or other control assembly(ies).
• Tank sensor assembly390 may include any suitable structure configured to detect and/or measure one or more suitable operating variables and/or parameters in the buffer tank and/or generate one or more signals based on the detected and/or measured operating variable(s) and/or parameter(s). For example, the tank sensor assembly may detect mass, volume, flow, temperature, electrical current, pressure, refractive index, thermal conductivity, density, viscosity, optical absorbance, electrical conductivity, and/or other suitable variable(s), and/or parameter(s). In some embodiments, the tank sensor assembly may detect one or more triggering events. For example,tank sensor assembly390 may include one ormore tank sensors400 configured to detect pressure, temperature, flowrate, volume, and/or other parameters.Tank sensors400 may, for example, be configured to detect pressure in the buffer tank and/or generate one or more signals based on the detected pressure.
• Product valve assembly392 may include any suitable structure configured to manage and/or direct flow inproduct conduit386. For example, the product valve assembly may allow the product hydrogen stream to flow from the fuel processing assembly to the buffer tank (as indicated at401), and/or ventproduct hydrogen stream382 from fuel processing assembly378 (as indicated at403). The vented product hydrogen stream may be discharged to atmosphere and/or to a vented product hydrogen management system (not shown).
• Product valve assembly392 may, for example, include afirst solenoid valve402 and asecond solenoid valve404. The first solenoid valve may include afirst solenoid406 and afirst valve408, while the second solenoid valve may include asecond solenoid410 and asecond valve412. As shown inFIGS. 18-19, the first valve may be configured to move between a plurality of positions, including a firstopen position407 and a firstclosed position409. Additionally, the second valve may be configured to move between a plurality of positions, including a secondopen position411 and a secondclosed position413.
• When the first valve is in the open position, the product hydrogen stream is allowed to flow from the fuel processing assembly to the buffer tank. In contrast, when the first valve is in the closed position, buffer tank is isolated from the product hydrogen stream from the fuel processing assembly (or the product hydrogen stream from the fuel processing assembly is not allowed to flow to the buffer tank). When the second valve is in the open position, the product hydrogen stream from the fuel processing assembly is vented. In contrast, when the second valve is in the closed position, the product hydrogen stream from the fuel processing assembly is not vented.
• First solenoid406 may be configured to movefirst valve408 between the open and closed positions based on input(s) received fromcontrol assembly394. Additionally,second solenoid410 may be configured to movesecond valve412 between the open and closed position based on input(s) received from the control assembly.
• Control assembly394 may include any suitable structure configured to controlfuel processing assembly378 and/orproduct valve assembly392 based, at least in part, on input(s) from buffertank sensor assembly390, such as based, at least in part, on detected and/or measured operating variable(s) and/or parameter(s) by the buffer tank sensor assembly.Control assembly394 may receive input(s) only from buffertank sensor assembly390 and/or the control assembly may receive input(s) from other sensor assemblies of the hydrogen generation assembly. Additionally,control assembly394 may control only the fuel processing assembly, only the product valve assembly, only both the fuel processing assembly and the product valve assembly, or the fuel processing assembly, product valve assembly and/or one or more other components of the hydrogen generation assembly.Control assembly394 may communicate with the fuel processing assembly, the buffer tank sensor assembly, and/or the product valve assembly viacommunication linkages393.Communication linkages393 may be any suitable wired and/or wireless mechanism for one- or two-way communication between the corresponding devices, such as input signals, command signals, measured parameters, etc.
• Control assembly394 may, for example, be configured to operatefuel processing assembly378 between the run and standby modes (and/or reduced output mode(s)) based, at least in part, on the detected pressure inbuffer tank388. For example,control assembly394 may be configured to operate the fuel processing assembly in the standby mode when the detected pressure in the buffer tank is above a predetermined maximum pressure, to operate the fuel processing assembly in one or more reduced output mode(s) when the detected pressure in the buffer tank is below a predetermined maximum pressure and/or above a predetermined operating pressure, and/or to operate the fuel processing assembly in the run mode when the detected pressure in the buffer tank is below a predetermined operating pressure and/or predetermined minimum pressure. The predetermined maximum and minimum pressures and/or predetermined operating pressure(s) may be any suitable pressures. For example, the one or more of the above pressures may be independently set based on a desired range of pressures for the fuel processing assembly, the product hydrogen in the buffer tank, and/or the pressure requirements of the hydrogen consuming device(s). Alternatively,control assembly394 may operate the fuel processing assembly to operate in the run mode within a predetermined range of pressure differentials (such as between the fuel processing assembly and the buffer tank and/or between the buffer tank and the hydrogen consuming device(s)), and in the reduced output and/or standby mode(s) when outside the predetermined range of pressure differentials.
• Additionally,control assembly394 may be configured to operate the product valve assembly based on, for example, input(s) from sensor assembly. For example, the control assembly may direct or control the first and/or second solenoids to move the first valve in the closed position and/or the second valve in the open position when the fuel processing assembly is in the standby mode. Additionally,control assembly394 may direct or control the first and/or second solenoids to move the first valve in the open position and/or the second valve in the closed position whenfuel processing assembly378 is in the run mode and/or reduced output mode(s).
• Control assembly394 may, for example, include acontroller414, aswitching device416, and apower supply418.Controller414 may have any suitable form, such as a computerized device, software executing on a computer, an embedded processor, programmable logic controller, an analog device, and/or functionally equivalent devices. Additionally, the controller may include any suitable software, hardware, and/or firmware.
• Switching device416 may include any suitable structure configured to allowcontroller414 to control the first and/or second solenoids. For example, the switching device may include a solid-state relay420.Power supply418 may include any suitable structure configured to provide power sufficient to control the first and/or second solenoids.
• Hydrogen generation assemblies of the present disclosure may include one or more of the following:
• • A feed assembly configured to deliver a feed stream to a fuel processing assembly.
  • A feed tank configured to contain feedstock for a feed stream.
  • A feed conduit fluidly connecting a feed tank and a fuel processing assembly.
  • A pump configured to deliver a feed stream at a plurality of flowrates to a fuel processing assembly via a feed conduit.
  • A feed sensor assembly configured to detect pressure in a feed conduit downstream from a pump.
  • A feed sensor assembly configured to generate a signal based on detected pressure.
  • A pump controller configured to select a flowrate from a plurality of flowrates based on detected pressure.
  • A pump controller configured to operate a pump at a selected flowrate.
  • A pump controller configured to select a flowrate for a pump based solely on detected pressure.
  • A pump controller configured to condition a signal received from a sensor assembly.
  • A pump controller configured to invert a signal received from a feed sensor assembly.
  • A pump controller configured to select a flowrate based on a conditioned signal.
  • A pump controller configured to select a flowrate based on an inverted signal.
  • A fuel processing assembly configured to receive a feed stream.
  • A fuel processing assembly configured to produce a product hydrogen stream from a feed stream.
  • A fuel processing assembly configured to be operable among a plurality of modes.
  • A fuel processing assembly configured to be operable among a run mode in which the fuel processing assembly produces a product hydrogen stream from a feed stream, and a standby mode in which the fuel processing assembly does not produce the product hydrogen stream from the feed stream.
  • A purge assembly.
  • A pressurized gas assembly configured to receive at least one container of pressurized gas that is configured to purge a fuel processing assembly.
  • A purge conduit configured to fluidly connect a pressurized gas assembly and a fuel processing assembly.
  • A purge valve assembly configured to allow at least one pressurized gas to flow through a purge conduit from a pressurized gas assembly to a hydrogen generation assembly when power to the hydrogen generation assembly is interrupted.
  • A solenoid valve that moves between a closed position in which at least one pressurized gas does not flow through a purge conduit from a pressurized gas assembly, and an open position in which the at least one pressurized gas is allowed to flow through the purge conduit from the pressurized gas assembly.
  • A solenoid valve that is in the closed position when there is power to a fuel processing assembly.
  • A solenoid valve that automatically moves to an open position when power to a fuel processing assembly is interrupted.
  • A solenoid valve configured to move to a closed position when the solenoid valve receives a control signal.
  • A solenoid valve configured to automatically move to an open position when the solenoid valve does not receive a control signal.
  • A control system configured to send a control signal to a solenoid valve.
  • An enclosure containing at least a portion of a fuel processing assembly and at least a portion of a purge assembly.
  • An enclosure having an exhaust port.
  • A hydrogen-producing region contained within an enclosure.
  • A hydrogen-producing region configured to produce, via a steam reforming reaction, a reformate stream from at least one feed stream.
  • A purification region contained within an enclosure.
  • A purification region including a hydrogen-selective membrane.
  • A purification region configured to produce a permeate stream comprised of the portion of a reformate stream that passes through a hydrogen-selective membrane, and a byproduct stream comprised of the portion of the reformate stream that does not pass through the membrane.
  • A reformer sensor assembly configured to detect temperature within a hydrogen-producing region.
  • A reformer sensor assembly configured to detect temperature in the purification region.
  • A heating assembly configured to receive at least one air stream and at least one fuel stream.
  • A heating assembly configured to combust at least one fuel stream within a combustion region contained within an enclosure producing a heated exhaust stream for heating at least a hydrogen-producing region to at least a minimum hydrogen-producing temperature.
  • A damper moveably connected to an exhaust port.
  • A damper configured to move among a plurality of positions.
  • A damper configured to move among a fully open position in which the damper allows a heated exhaust stream to flow through an exhaust port, a closed position in which the damper prevents the heated exhaust stream from flowing through the exhaust port, and a plurality of intermediate open positions between the fully open and closed positions.
  • A damper controller configured to move a damper between fully open and closed positions based, at least in part, on a detected temperature in a hydrogen-producing region.
  • A damper controller configured to move a damper between fully open and closed positions based, at least in part, on a detected temperature in at least one of a hydrogen-producing region and a purification region.
  • A damper controller configured to move a damper toward a closed position when a detected temperature is above a predetermined maximum temperature.
  • A damper controller configured to move a damper toward an open position when a detected temperature is below a predetermined minimum temperature.
  • A buffer tank configured to contain a product hydrogen stream.
  • A product conduit fluidly connecting a fuel processing assembly and a buffer tank.
  • A tank sensor assembly configured to detect pressure in a buffer tank.
  • A product valve assembly configured to manage flow in a product conduit.
  • At least one valve that is configured to operate between a flow position in which a product hydrogen stream from a fuel processing assembly flows through a product conduit and into a buffer tank, and a vent position in which the product hydrogen stream from the fuel processing assembly is vented prior to the buffer tank.
  • A three-way solenoid valve.
  • A first valve configured to control flow of a product hydrogen stream between a fuel processing assembly and a buffer tank.
  • A first valve configured to move between a first open position in which a product hydrogen stream flows between a fuel processing assembly and a buffer tank, and a first closed position in which the product hydrogen stream does not flow between the fuel processing assembly and the buffer tank.
  • A second valve configured to vent a product hydrogen stream from a fuel processing assembly.
  • A second valve configured to move between a second open position in which a product hydrogen stream is vented, and a second closed position in which the product hydrogen stream is not vented.
  • A control assembly configured to operate a fuel processing assembly between run and standby modes based, at least in part, on detected pressure.
  • A control assembly configured to operate a fuel processing assembly in a standby mode when detected pressure in a buffer tank is above a predetermined maximum pressure.
  • A control assembly configured to operate a fuel processing assembly in a run mode when detected pressure in a buffer tank is below a predetermined minimum pressure.
  • A control assembly configured to direct a product valve assembly to vent a product hydrogen stream from a fuel processing assembly when the fuel processing assembly is in the standby mode.
  • A control assembly configured to move at least one valve to a flow position when a fuel processing assembly is in a run mode.
  • A control assembly configured to move at least one valve to a vent position when a fuel processing assembly is in a standby mode.
  • A control assembly configured to move a first valve to a first open position and a second valve to a second closed position when a fuel processing assembly is in a run mode.
  • A control assembly configured to move a first valve to a first closed position and a second valve to a second open position when a fuel processing assembly is in a standby mode.
INDUSTRIAL APPLICABILITY
• The present disclosure, including hydrogen generation assemblies, hydrogen purification devices, and components of those assemblies and devices, is applicable to the fuel-processing and other industries in which hydrogen gas is purified, produced, and/or utilized.
• The disclosure set forth above encompasses multiple distinct inventions with independent utility. While each of these inventions has been disclosed in its preferred form, the specific embodiments thereof as disclosed and illustrated herein are not to be considered in a limiting sense as numerous variations are possible. The subject matter of the inventions includes all novel and non-obvious combinations and subcombinations of the various elements, features, functions and/or properties disclosed herein. Similarly, where any claim recites “a” or “a first” element or the equivalent thereof, such claim should be understood to include incorporation of one or more such elements, neither requiring nor excluding two or more such elements.
• Inventions embodied in various combinations and subcombinations of features, functions, elements, and/or properties may be claimed through presentation of new claims in a related application. Such new claims, whether they are directed to a different invention or directed to the same invention, whether different, broader, narrower or equal in scope to the original claims, are also regarded as included within the subject matter of the inventions of the present disclosure.

Claims (35)

What is claimed is:

1. A hydrogen generation assembly, comprising:

a fuel processing assembly configured to receive a feed stream and produce a product hydrogen stream from the feed stream;

a feed assembly configured to deliver the feed stream to the fuel processing assembly, the feed assembly including:

a feed tank configured to contain feedstock for the feed stream,

a feed conduit fluidly connecting the feed tank and the fuel processing assembly, and

a pump configured to deliver the feed stream at a plurality of flowrates to the fuel processing assembly via the feed conduit; and

a control system, including:

a feed sensor assembly configured to detect pressure in the feed conduit downstream from the pump, and

a pump controller configured to select a flowrate from the plurality of flowrates based on the detected pressure in the feed conduit, and to operate the pump at the selected flowrate.

2. The assembly ofclaim 1, wherein the pump controller is further configured to select the flowrate based solely on the detected pressure in the feed conduit.

3. The assembly ofclaim 1, wherein the feed sensor assembly is further configured to generate a signal based on the detected pressure in the feed conduit, the pump controller being further configured to condition the signal received from the sensor assembly and to select the flowrate based on the conditioned signal.

4. The assembly ofclaim 3, wherein the pump controller is further configured to invert the signal received from the feed sensor assembly and to select the flowrate based on the inverted signal.

5. The assembly ofclaim 1, further comprising a purge assembly, including:

a pressurized gas assembly fluidly connected to the feed conduit and configured to receive at least one container of pressurized gas that is configured to purge the fuel processing assembly; and

a purge valve assembly configured to allow the at least one pressurized gas to flow through the feed conduit from the pressurized gas assembly to the fuel processing assembly when power to the fuel processing assembly is interrupted.

6. The assembly ofclaim 1, further comprising an enclosure having an exhaust port, the fuel processing assembly including a hydrogen-producing region contained within the enclosure and configured to provide, via a steam reforming reaction, the product hydrogen stream from the feed stream, wherein the control system further includes a reformer sensor assembly configured to detect temperature in the hydrogen-producing region.

7. The assembly ofclaim 6, further comprising:

a heating assembly configured to receive at least one air stream and at least one fuel stream and to combust the at least one fuel stream within a combustion region contained within the enclosure producing a heated exhaust stream for heating at least the hydrogen-producing region to at least a minimum hydrogen-producing temperature; and

a damper moveably connected to the exhaust port and configured to move among a plurality of positions including a fully open position in which the damper allows the heated exhaust stream to flow through the exhaust port, a closed position in which the damper prevents the heated exhaust stream from flowing through the exhaust port, and a plurality of intermediate open positions between the fully open and closed positions, and wherein the control system further includes a damper controller configured to move the damper between the fully open and closed positions based, at least in part, on the detected temperature in the hydrogen-producing region.

8. The assembly ofclaim 1, wherein the fuel processing assembly is further configured to be operable among a plurality of modes, including a run mode in which the fuel processing assembly produces the product hydrogen stream from the feed stream, and a standby mode in which the fuel processing assembly does not produce the product hydrogen stream from the feed stream.

9. The assembly ofclaim 8, further comprising a buffer tank configured to contain the product hydrogen stream, and a product conduit fluidly connecting the fuel processing assembly and the buffer tank, wherein the control system further includes:

a product sensor assembly configured to detect pressure in the buffer tank, and

a control assembly configured to operate the fuel processing assembly between the run and standby modes based, at least in part, on the detected pressure in the buffer tank.

10. A hydrogen generation assembly, comprising:

a fuel processing assembly configured to receive a feed stream and produce a product hydrogen stream from the feed stream;

a pressurized gas assembly configured to receive at least one container of pressurized gas that is configured to purge the fuel processing assembly;

a purge conduit configured to fluidly connect the pressurized gas assembly and the fuel processing assembly; and

a purge valve assembly configured to allow the at least one pressurized gas to flow through the purge conduit from the pressurized gas assembly to the fuel processing assembly when power to the fuel processing assembly is interrupted.

11. The assembly ofclaim 10, wherein the purge valve assembly includes a purge valve that moves between a closed position in which the at least one pressurized gas does not flow through the purge conduit from the pressurized gas assembly, and an open position in which the at least one pressurized gas is allowed to flow through the purge conduit from the pressurized gas assembly.

12. The assembly ofclaim 11, wherein the purge valve is in the closed position when there is power to the fuel processing assembly, and wherein the purge valve automatically moves to the open position when power to the fuel processing assembly is interrupted.

13. The assembly ofclaim 11, wherein the purge valve assembly further includes a purge solenoid configured to move the purge valve between the open and closed positions, the fuel processing assembly including a control system configured to send a control signal to the purge solenoid, and wherein the purge solenoid is configured to move the purge valve to the closed position when the purge solenoid receives the control signal, and to automatically move the purge valve to the open position when the purge solenoid does not receive the control signal.

14. The assembly ofclaim 10, wherein at least a portion of the fuel processing assembly and at least a portion of the purge assembly are contained within an enclosure.

15. A steam reforming hydrogen generation assembly configured to receive at least one feed stream and generate a reformate stream containing hydrogen gas as a majority component and other gases, comprising:

an enclosure having an exhaust port;

a hydrogen-producing region contained within the enclosure and configured to produce, via a steam reforming reaction, the reformate stream from the at least one feed stream;

a reformer sensor assembly configured to detect temperature in the hydrogen-producing region;

a heating assembly configured to receive at least one air stream and at least one fuel stream and to combust the at least one fuel stream within a combustion region contained within the enclosure producing a heated exhaust stream for heating at least the hydrogen-producing region to at least a minimum hydrogen-producing temperature; and

a damper moveably connected to the exhaust port and configured to move among a plurality of positions including a fully open position in which the damper allows the heated exhaust stream to flow through the exhaust port, a closed position in which the damper prevents the heated exhaust stream from flowing through the exhaust port, and a plurality of intermediate open positions between the fully open and closed positions, and

a damper controller configured to move the damper between the fully open and closed positions based, at least in part, on the detected temperature in the hydrogen-producing region.

16. The assembly ofclaim 15, further comprising a purification region contained within the enclosure and including a hydrogen-selective membrane, the purification region being configured to produce a permeate stream comprised of the portion of the reformate stream that passes through the hydrogen-selective membrane, and a byproduct stream comprised of the portion of the reformate stream that does not pass through the membrane, wherein the reformer sensor assembly is further configured to detect temperature in the purification region and the damper controller is configured to move the damper between the fully open and closed positions based, at least in part, on the detected temperature in at least one of the hydrogen-producing region and the purification region.

17. The assembly ofclaim 15, wherein the damper controller is configured to move the damper toward the closed position when the detected temperature is above a predetermined maximum temperature.

18. The assembly ofclaim 15, wherein the damper controller is configured to move the damper toward the fully open position when the detected temperature is below a predetermined minimum temperature.

19. The assembly ofclaim 15, further comprising:

a purge gas assembly configured to receive at least one container of pressurized gas that is configured to purge the hydrogen-producing region;

a purge conduit configured to fluidly connect the pressurized gas assembly and the hydrogen-producing region; and

a purge valve assembly configured to allow the at least one pressurized gas to flow through the purge conduit from the pressurized gas assembly to the hydrogen-producing region when power to the hydrogen-producing region is interrupted.

20. The assembly ofclaim 19, further comprising a purification region contained within the enclosure and fluidly connected to the hydrogen-producing region, the purification region including a hydrogen-selective membrane, the at least one container of pressurized gas being configured to purge the hydrogen-selective membrane, and the purge valve assembly being configured to allow the at least one pressurized gas to flow through the purge conduit from the pressurized gas assembly to the hydrogen-selective membrane when power to the hydrogen-producing region is interrupted.

21. The assembly ofclaim 15, wherein the hydrogen-producing region is configured to be operable between a plurality of modes, including a run mode in which the hydrogen-producing region produces the reformate stream from the at least one feed stream, and a standby mode in which the hydrogen-producing region does not produce the reformate stream from the at least one feed stream, the assembly further comprising:

a buffer tank configured to contain the reformate stream;

a product conduit fluidly connecting the hydrogen-producing region and the buffer tank;

a buffer tank sensor assembly configured to detect pressure in the buffer tank; and

a reformer controller configured to operate the hydrogen-producing region between the run and standby modes based, at least in part, on the detected pressure in the buffer tank.

22. A hydrogen generation assembly, comprising:

a fuel processing assembly configured to receive a feed stream and to be operable among a plurality of modes, including a run mode in which the fuel processing assembly produces a product hydrogen stream from the feed stream, and a standby mode in which the fuel processing assembly does not produce the product hydrogen stream from the feed stream;

a buffer tank configured to contain the product hydrogen stream;

a product conduit fluidly connecting the fuel processing assembly and the buffer tank;

a tank sensor assembly configured to detect pressure in the buffer tank; and

a control assembly configured to operate the fuel processing assembly between the run and standby modes based, at least in part, on the detected pressure in the buffer tank.

23. The assembly ofclaim 22, wherein the control assembly is configured to operate the fuel processing assembly in the standby mode when the detected pressure in the buffer tank is above a predetermined maximum pressure.

24. The assembly ofclaim 22, wherein the control assembly is configured to operate the fuel processing assembly in the run mode when the detected pressure in the buffer tank is below a predetermined minimum pressure.

25. The assembly ofclaim 22, further comprising a product valve assembly configured to manage flow in the product conduit, wherein the control assembly is configured to direct the product valve assembly to vent the product hydrogen stream from the fuel processing assembly when the fuel processing assembly is in the standby mode.

26. The assembly ofclaim 25, wherein the product valve assembly includes at least one valve that is configured to operate between a flow position in which the product hydrogen stream from the fuel processing assembly flows through the product conduit and into the buffer tank, and a vent position in which the product hydrogen stream from the fuel processing assembly is vented prior to the buffer tank.

27. The assembly ofclaim 26, wherein the control assembly is further configured to move the at least one valve to the flow position when the fuel processing assembly is in the run mode.

28. The assembly ofclaim 26, wherein the control assembly is further configured to move the at least one valve to the vent position when the fuel processing assembly is in the standby mode.

29. The assembly ofclaim 26, wherein the at least one valve is a three-way valve.

30. The assembly ofclaim 26, wherein the at least one valve includes a first valve configured to control flow of the product hydrogen stream between the fuel processing assembly and the buffer tank, and a second valve configured to vent the product hydrogen stream from the fuel processing assembly.

31. The assembly ofclaim 30, wherein the first valve is configured to move between a first open position in which the product hydrogen stream flows between the fuel processing assembly and the buffer tank, and a first closed position in which the product hydrogen stream does not flow between the fuel processing assembly and the buffer tank, wherein the second valve is configured to move between a second open position in which the product hydrogen stream is vented, and a second closed position in which the product hydrogen stream is not vented.

32. The assembly ofclaim 31, wherein the control assembly is further configured to move the first valve to the first open position and the second valve in the second closed position when the fuel processing assembly is in the run mode.

33. The assembly ofclaim 32, wherein the control assembly is further configured to move the first valve to the first closed position and the second valve in the second open position when the fuel processing assembly is in the standby mode.

34. The assembly ofclaim 22, further comprising:

a purge gas assembly configured to receive at least one container of pressurized gas that is configured to purge the fuel processing assembly;

a purge conduit configured to fluidly connect the pressurized gas assembly to the fuel processing assembly; and

a purge valve assembly configured to allow the at least one pressurized gas to flow through the purge conduit from the pressurized gas assembly to the fuel processing assembly when the fuel processing assembly is in the standby mode.

35. The assembly ofclaim 22, further comprising:

a purge gas assembly configured to receive at least one container of pressurized gas that is configured to purge the fuel processing assembly;

a purge conduit configured to fluidly connect the pressurized gas assembly to the fuel processing assembly; and

a purge valve assembly configured to allow the at least one pressurized gas to flow through the purge conduit from the pressurized gas assembly to the fuel processing assembly when power to the fuel processing assembly is interrupted.

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