Abstract:
An apparatus for making hydrogen from a hydrocarbon feedstock and steam using heat stored in a vessel followed by the regeneration of the vessel to restore the heat. Regeneration is done by preheating within the vessel a hydrogen purge gas and steam. Downstream of the conventional reform catalyst, the preheated gases are mixed with an oxygen containing gas so that they combust within the vessel in a fuel lean mode and heat material disposed in the vessel. This is the heat which is used in converting the hydrogen feedstock to hydrogen. The addition of steam in the regeneration process to recover the heat remaining in the vessel following the hydrogen make cycle simplifies reactor bed design and improves operational flexibility. Incorporation of a regeneratable sulfur absorber in the vessel facilitates the removal of up to 90% of the feedstock sulfur.
Abstract:
A pair of reaction vessels provide hydrogen to a fuel cell by making hydrogen in one of the vessels while simultaneously regenerating the other vessel, and then reversing the function of the vessels. In the vessel making hydrogen a hydrocarbon feedstock is cracked and steam reformed using sensible heat generated during the regeneration of the vessel. Regeneration includes preheating, separately within the reaction vessel, fuel cell fuel electrode exhaust and an oxygen containing gas. Preheating is accomplished using the heat of combustion and/or sensible heat stored within material disposed within the vessel while it is making hydrogen. After being preheated the fuel electrode exhaust and oxygen containing gas are allowed to mix and combust within the vessel, thereby heating materials disposed therein. This heat is the heat used to crack and steam reform the hydrocarbon fuel.
Abstract:
In a fuel cell power plant the anode and cathode exhausts are combined and burned in a burner with a first portion of the burner exhaust being delivered into fuel conditioning apparatus to provide the heat for converting a carbonaceous fuel to hydrogen. The hydrogen is then fed to the anode side of the fuel cells. A second portion of the burner exhaust is preferably used to drive a turbocharger for compressing the fuel cell oxidant which is usually air. If the fuel cells do not operate on pressurized reactants, then the energy in the second portion of the burner exhaust can be used for any other suitable purpose.
Abstract:
A compact and efficient fuel reformer which is operable to produce a hydrogen-enriched process fuel from a raw fuel such as natural gas, or the like includes a compact array of catalyst tubes which are contained in a heat-insulated housing. The catalyst tube array preferably includes a multitude of catalyst tubes that are arranged in a hexagonal array. The housing includes internal hexagonal thermal insulation so as to ensure even heating of the catalyst tubes. The diameter of the tubes is sized so that spacing between adjacent tubes in the array can be minimized for efficient heat transfer. The interior of each of the catalyst tubes includes a hollow dead-ended central tube which serves as a fines trap for collecting catalyst fines that may become entrained in the fuel stream. The catalyst tubes are also provided with an upper frusto-conical portion which serves to extend the catalyst bed and provide a catalyst reserve. The assembly includes a side-fired startup burner which allows for an improved diffusion burner orifice array at the top of the reformer. The catalyst tubes are supported by side walls of the assembly in a manner that stabilizes the tubes in the assembly. In the assembly, the internal transverse manifold plates are tied together by portions of the tube assemblies so as to form a composite beam that supports the weight of the catalyst tube array.
Abstract:
A fuel cell power plant recycles a first portion of the exhaust of a main stack within the main stack and utilizes a second portion of the exhaust to provide fuel to a vent stack. The ratio of fuel cells between the main stack and the vent stack is greater than 3:1 and is preferably 9:1.
Abstract:
The steam for a steam reforming reactor of a fuel cell powerplant is generated by humidifying the reactor feed gas in a saturator by evaporating a small portion of a mass of liquid water which circulates in a loop passing through the saturator. The water is reheated in each pass through the loop by waste heat from the fuel cell, but is not boiled. In the saturator the relatively dry feed gas passes in direct contact with the liquid water over and through a bed a high surface area material to cause evaporation of some of the water in the loop. All the steam requirements for the reactor can be generated in this manner without the need for a boiler; and steam can be raised at a higher total pressure than in a boiler heated by the same source.
Abstract:
A system is disclosed for removing electrolyte from a fuel cell gas stream. The gas stream containing electrolyte vapor is supercooled utilizing conventional heat exchangers and the thus supercooled gas stream is passed over high surface area passive condensers. The condensed electrolyte is then drained from the condenser and the remainder of the gas stream passed on. The system is particularly useful for electrolytes such as phosphoric acid and molten carbonate, but can be used for other electrolyte cells and simple vapor separation as well.
Abstract:
A catalytic reaction vessel makes hydrogen from a hydrocarbon feedstock and steam using heat stored in the vessel, and the vessel is then regenerated to restore the heat. Regeneration is done by preheating, separately and within the vessel, an oxygen containing gas and a hydrogen purge gas, and mixing these preheated gases so that they combust within the vessel and heat material disposed in the vessel. This is the heat which is used in converting the hydrocarbon feedstock to hydrogen.
Abstract:
A process is disclosed for making hydrogen from a hydrocarbon feedstock and steam using heat stored in a vessel, and the vessel is then regenerated to restore the heat. Regeneration is done by preheating, separately and within the vessel, an oxygen containing gas and a hydrogen purge gas, and mixing these preheated gases so that they combust within the vessel and heat material disposed in the vessel. This is the heat which is used in converting the hydrocarbon feedstock to hydrogen.
Abstract:
A catalytic reaction apparatus, such as for steam reforming a hydrocarbon feedstock to produce hydrogen, includes a tubular reactor disposed within a furnace. The reactor includes an annular reaction chamber which is heated along its outer wall by a countercurrent flow of furnace gases traveling through a narrow annulus external thereof. The reaction chamber is also heated along its inner wall by regenerative heat from the reaction products which leave the annular chamber and flow countercurrent to the flow within the reaction chamber through a narrow annulus disposed along the inner wall thereof. This apparatus is capable of high reactor thermal efficiency over a wide range of heating rates, including very high heating rates. The apparatus is very compact and is particularly suited for use with a large number of closely packed tubular reactors disposed within a single furnace.