Fuel Cell Gas Purification

A purification process for hydrogen fuel cell vehicles that simultaneously removes a wide range of impurities like aldehydes, acids, ammonia, CO2, halogens, CO, O2 and sulfur from hydrogen sources to meet the stringent purity requirements for hydrogen fuel cell vehicles. The process involves using two specialized purification materials, A and B, connected in series. Material A removes aldehydes, acids, ammonia, CO2, halogens, etc. at lower temperatures. Material B removes CO, O2 and sulfur. The materials are optimized compositions of modified molecular sieves and copper silicates.

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A hydrogen purification system for removing impurities like oxygen and water vapor from hydrogen produced by alkaline water electrolysis to generate high-purity hydrogen. The system uses a deoxidation reactor with a catalyst to remove oxygen, followed by cooling, gas-liquid separation, drying, and filtration steps to further purify the hydrogen. The deoxidation, cooling, and drying steps are performed in parallel to enable continuous hydrogen production. The cooling and separation steps remove water vapor, while the drying steps remove remaining water. The system uses molecular sieve adsorption drying to achieve high hydrogen purity levels.

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A crude hydrogen purification system that uses a series connection of a pressure swing adsorption unit and multiple solid-state lithium batteries to efficiently remove impurities like nitrogen from crude hydrogen and increase hydrogen yield. The system involves using a pressure swing adsorption unit to initially remove impurities from the hydrogen-containing feed gas. The nitrogen-containing and hydrogen-rich gas stream is then passed through parallel-connected solid-state lithium batteries. During discharge, the lithium batteries capture nitrogen from the gas stream and release pure hydrogen. Charging the batteries regenerates them by releasing nitrogen. This allows selective separation of hydrogen and nitrogen. A buffer tank can store some of the gas stream between the adsorber and batteries to purge the adsorber.

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Tail exhaust hydrogen collection system for megawatt-scale fuel cell power plants that recycles and purifies the high-concentration hydrogen exhaust from the fuel cells to improve efficiency and reduce waste. The system consists of a gas-liquid separator, hydrogen purifier, and storage tank connected to the tail hydrogen outlet of the fuel cells. It removes water and concentrates the hydrogen before storing it. This allows recycling the hydrogen back into the fuel cell stack without diluting it with air, reducing hydrogen waste and improving overall system efficiency compared to diluting the exhaust hydrogen with air.

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Hydrogen recovery and purification system that efficiently recovers heavy components and purifies hydrogen from feed gas. The system uses a combination of condensation, absorption, and hydrogen separation steps. Heavy components are preliminarily condensed and separated, then deeply absorbed. The remaining gas is purified by pressure swing adsorption or membrane separation. This reduces impurities in the hydrogen separation step, improving purity and yield.

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Hierarchical purification system for hydrogen that combines pressure swing adsorption (PSA) and electrochemical purification to achieve high hydrogen recovery and purity. The system involves sequentially treating hydrogen feed gas with PSA to remove CO, CO2, and some hydrocarbons, followed by electrochemical purification to further remove impurities like N2 and Ar. The PSA step uses an adsorbent to capture CO. The electrochemical step involves passing hydrogen through an electrochemical cell with a membrane.

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A system and method for coupling catalytic and metal hydrogen storage alloys to purify high-purity hydrogen. The system involves using a catalytic unit to convert CO to CO2/methane in the hydrogen stream, followed by a metal hydrogen storage alloy unit to remove impurities and isolate hydrogen. This allows higher CO tolerance in the catalytic unit and higher hydrogen recovery compared to conventional methods. The catalytic unit can also regenerate in situ without high temperatures. Heat exchange and adsorption units can be added between steps.

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A hydrogen circulation CO removal system for proton exchange membrane fuel cells that allows efficient CO removal from hydrogen fuel to improve fuel cell performance. The system has a closed loop with a storage tank, pressure regulator, injector, ejector, CO removal module, fuel cell stack, and separator arranged in sequence. Hydrogen flows through the loop with purification in the CO removal module before entering the fuel cell stack. Unreacted hydrogen from the stack goes back through the loop to be recycled and purified again.

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Efficiently producing hydrogen from fuel cell exhaust for fuel cell applications, using a multi-stage pressure swing adsorption process. The method involves compressing the fuel cell exhaust, concentrating hydrogen in a first adsorption stage, compressing again, and then further purifying in a second adsorption stage. This allows upgrading the hydrogen concentration and impurity removal with minimal energy consumption using the fuel cell's own power.

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A process to extract hydrogen from ethylene glycol production tail gas to produce hydrogen for fuel cells. The process involves condensation, molecular sieve adsorption, and pressure swing adsorption steps to purify and separate the hydrogen-rich tail gas. This allows recovering and utilizing the hydrogen instead of flaring or discharging the tail gas. It improves efficiency and reduces pollution compared to direct combustion or recycling.

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Purification method for hydrogen-containing gas with high hydrogen recovery and carbon capture. The method involves two-stage purification: pressure swing adsorption (PSA) to capture heavy components like CO2, followed by electrochemical purification to separate hydrogen from the lighter components. This allows preparing high-purity hydrogen while capturing carbon dioxide and other heavy components. The PSA regeneration uses the non-hydrogen gases from electrochemical purification as purge.

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Efficient process for producing ultra-high purity hydrogen using a combination of cryogenic cooling, adsorption, and regeneration steps. The process involves cooling the hydrogen feed stream to a low temperature, passing it through an online adsorber at cryogenic temperatures to remove impurities, and regenerating the adsorber at ambient temperature to recover the hydrogen. This allows high purity hydrogen production with high recovery compared to traditional cryogenic methods. The cold hydrogen can also be further purified using liquid hydrogen wash or getter adsorption.

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A method to control hydrogen purging in fuel cell vehicles to prevent damage and improve efficiency. It uses an algorithm to estimate hydrogen concentration in the fuel cell stack by monitoring voltage and pressure changes when the hydrogen injection valve is closed. If the concentration falls below a threshold during injection pulses, the purge valve opens to remove water and nitrogen.

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A process to produce ultra-pure hydrogen with high recovery using a cryogenic adsorption system that can be integrated with existing hydrogen purification processes like pressure swing adsorption (PSA). The process involves cooling the hydrogen feed stream to produce a cooled hydrogen stream, then passing it through an online adsorber at cryogenic temperatures to adsorb impurities. The adsorber is regenerated with a cold stream like liquid hydrogen, and the spent regeneration gas is enriched in impurities. This regenerated stream can be used to purge the PSA beds. The cooled hydrogen stream can also be passed through a liquid hydrogen wash column to further purify. The process provides high impurity removal compared to just PSA, especially for impurities like argon that desorb at lower temperatures.

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A process to produce ultra-pure hydrogen with high recovery using a cryogenic temperature swing adsorption (CTSA) system. It involves cooling the hydrogen feed stream, adsorbing impurities at cryogenic temps, and regenerating the adsorber with a warm gas. This is combined with a pressure swing adsorption (PSA) step to further purify the hydrogen. The CTSA recycles spent regeneration gas back to the PSA to improve overall hydrogen recovery. The PSA can also be integrated with a cryogenic wash column for further impurity removal. The CTSA can be used as a standalone step for high purity hydrogen production.

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Increasing hydrogen permeability of hydrogen separation membranes in hydrogen production systems like fuel processors without removing them. The method involves selectively exposing the membranes to an oxidant-containing stream while the system is operating. This oxidation process removes contaminants that reduce permeability. The system monitors parameters like hydrogen flow and feed pressure to determine when to switch from production to recovery mode. In recovery, oxidant is delivered to the membranes at controlled flow rates and durations to increase permeability. This allows in situ membrane maintenance without system downtime or membrane replacement.

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A process for purifying hydrogen for fuel cells using adsorbents between the hydrogen storage tank and the fuel cell. The process involves passing the hydrogen stream containing impurities through a purifier containing an adsorbent like MOFs, POPs, or COFs at purification conditions. This removes contaminants like carbon monoxide from the hydrogen, making it suitable for fuel cells without harming the catalyst. The purified hydrogen is then fed to the fuel cell. The adsorbents can be regenerated by changing temperature or pressure.

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Techniques to control purging of fuel cells to remove accumulated gases and water at the anode, without excessive purging. The method involves periodically opening a purge valve when the fuel cell is at a lower pressure than its nominal operating pressure. The lower pressure is 70-95% of the nominal pressure. If the purge valve doesn't open within a maximum time, it could indicate a valve jam.

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Fuel cell system that improves hydrogen utilization by separating and recycling hydrogen from nitrogen exhaust to prevent waste and tail hydrogen exceeding discharge limits. The system connects the fuel cell stack to a manifold with a steam-water separator, hydrogen membrane separator, and bypass line. Nitrogen exhaust exits through a valve and goes through the hydrogen separator to recycle the hydrogen back to the stack. This prevents hydrogen from the exhaust entering the tail stream and potentially exceeding discharge limits.

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Two-stage purification system for fuel cell hydrogen that removes trace sulfide and carbon monoxide impurities efficiently. The system has parallel desulfurization and decarburization units. The desulfurization unit removes sulfides like hydrogen sulfide using sulfide adsorbents. The decarburization unit removes carbon monoxide using carbon monoxide adsorbents. The adsorption devices are switched when impurity concentrations reach thresholds. This allows continuous operation without cyclic pressure swing. The switching prevents saturation of adsorbents. The desulfurization unit switches sulfide adsorbents and the decarburization unit switches carbon monoxide adsorbents. This ensures optimal impurity removal. The system has separate hydrogen inlets, outlets, and regeneration units for each stage.

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