Wet Oxidation Hydrogen Purification via Metal Redox Cycles
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Solution Overview
Problem
Current hydrogen gas supply methods for fuel cells, such as tube trailers, pipelines, and on-site production, face challenges like high infrastructure costs, contamination risks, and inefficiencies, particularly in decentralized applications like hydrogen refueling stations, where high purity hydrogen is required but not always economically viable or safe to produce.
Innovation Solution
A process involving the use of existing gas infrastructure to transport hydrogen gas with lower purity, combined with a local purification method where raw hydrogen gas is purified by reducing metal oxides with the hydrogen stream and subsequent oxidation with water, producing a highly pure hydrogen gas stream suitable for fuel cells, utilizing iron oxides and porous beds for efficient gas flow and contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydrogen gas is transported through dedicated infrastructure (tube trailers or pipelines), then high purity hydrogen supply is achieved, but infrastructure costs and complexity increase significantly
Solution Approach 1:
The patent enables existing natural gas infrastructure to serve dual purposes: transporting both natural gas and hydrogen gas. By using the same pipeline network for both gases, the system eliminates the need for dedicated hydrogen infrastructure while maintaining hydrogen supply capability, thus reducing infrastructure complexity and costs.
Solution Approach 2:
The patent changes the purity parameter of hydrogen gas in the pipeline from high purity (99.97% or higher) to lower purity (85-99% hydrogen with acceptable impurities). This parameter change allows the use of existing natural gas infrastructure, as the infrastructure can tolerate the presence of impurities like carbon dioxide, water vapor, and other gases without requiring specialized purification systems throughout the transport network.
2Device complexity
If impure hydrogen gas is used in existing infrastructure, then infrastructure costs are reduced, but contamination risks increase
Solution Approach 1:
The patent introduces a local purification unit as an intermediary component at the point of use (e.g., refueling station). This unit receives impure hydrogen gas from the existing infrastructure and performs final purification to meet fuel cell requirements. The purification unit acts as a mediator between the low-purity pipeline infrastructure and the high-purity requirement of fuel cells, eliminating contamination risks without requiring pure gas throughout the entire infrastructure.
3Object-affected harmful factors
If hydrogen gas is produced on site at the refueling station, then contamination risks are reduced, but production costs and complexity increase
Solution Approach 1:
The patent extracts the purification function from a centralized on-site production system and relocates it to a distributed local purification unit. Instead of producing and purifying hydrogen entirely at the refueling station, the system transports impure hydrogen through existing infrastructure and performs purification locally at the point of use. This extraction reduces the complexity of on-site production while maintaining low contamination risk.
4Device complexity
If existing gas infrastructure is used for hydrogen transport, then infrastructure costs are reduced, but purity requirements for the gas stream become less stringent
Solution Approach 1:
The patent segments the hydrogen supply system into two distinct stages: (1) transport stage through existing natural gas infrastructure where lower purity (85-99% hydrogen) is acceptable, and (2) final purification stage at the point of use where gas is purified to fuel cell specifications (99.97% or higher). This segmentation allows each stage to operate with appropriate purity levels for its specific function, reducing overall infrastructure requirements while maintaining final product quality.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method achieves hydrogen gas purity of 99.97% or more, meeting ISO 14687-2 standards, while reducing infrastructure costs and contamination risks, and allows for the use of existing gas infrastructure, enabling flexible and efficient hydrogen supply for decentralized applications like hydrogen refueling stations.
Implementation Method 1
contacting said raw hydrogen gas stream with an oxidized bed comprising an oxidized metal resulting in a waste gas stream comprising water, carbon dioxide and less than 5% hydrogen gas, and in a reduction of said oxidized metal
Implementation Method 2
contacting a bed comprising a reduced metal with water to produce a purified hydrogen gas stream comprising more than 99% hydrogen gas, preferably 99.97% or more and more preferably comprising 99.997% or more hydrogen gas, and an oxidized metal
Data Source
AI summary
The invention is directed to a process for the purification of a raw hydrogen gas stream comprising hydrogen gas in an amount of 85-99%, said process comprising the step of contacting said raw hydrogen gas stream with an oxidized bed comprising an oxidized metal resulting in a waste gas stream comprising water and less than 5% hydrogen gas, and in a reduction of said oxidized metal; and a step of contacting a bed comprising a reduced metal with water to produce a purified hydrogen gas stream comprising more than 99% hydrogen gas, preferably comprising 99.97% or more hydrogen gas, and the oxidized metal. In a further aspect, the invention is directed to an apparatus suitable to carry out said process.