Fibrous Substrates for Hydrogen Generation via Pyrolysis
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Solution Overview
Problem
In environmental control systems, especially in spacecraft or submarines, the pyrolysis of hydrocarbons generates solid carbon as a byproduct, which forms soot that can foul surfaces and decrease air quality, and existing methods for oxygen recovery from carbon dioxide waste oxygen, leading to inefficiencies and maintenance challenges.
Innovation Solution
The use of fibrous substrates with high surface area to volume ratios and optimized void fractions to collect and manage carbon deposition during pyrolysis, reducing soot formation and extending the operational life of the substrates by varying their surface area and density along the reactor axis, and monitoring hydrocarbon precursor concentrations to control carbon deposition and maintain substrate effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If fibrous substrates with high surface area are used to reduce soot formation, then carbon deposition effectiveness improves, but substrate weight and volume increase
Solution Approach 1:
The substrate employs varying fiber diameters across different regions - smaller diameter fibers (5-10 microns) in high carbon deposition zones and larger diameter fibers (15-30 microns) in low deposition zones. This local variation optimizes surface area where needed while reducing overall substrate mass, resolving the contradiction between soot reduction effectiveness and substrate weight.
Solution Approach 2:
The substrate is divided into multiple zones with different fiber density and diameter characteristics along the reactor axis. This segmentation allows high surface area regions to capture carbon effectively while low surface area regions reduce overall weight, achieving both soot formation reduction and weight management simultaneously.
2Weight of moving object
If substrate void fraction is increased to reduce density and weight, then substrate weight decreases, but carbon loading capacity reduces
Solution Approach 1:
The substrate structure varies locally along the reactor axis with different void fractions optimized for specific deposition rates. Regions with high carbon deposition rates have lower void fraction to maximize loading capacity, while regions with low deposition rates have higher void fraction to reduce overall density and weight, resolving the contradiction between weight reduction and carbon loading capacity.
3Object-affected harmful factors
If substrate surface area is increased to prevent sooty carbon formation, then carbon deposition effectiveness improves, but substrate volume increases
Solution Approach 1:
The substrate employs spatially varying fiber diameters and densities - smaller diameter fibers providing higher surface area to volume ratio in regions requiring high carbon capture, while larger diameter fibers reduce overall substrate volume in regions with lower deposition requirements, simultaneously preventing sooty carbon formation and minimizing substrate volume.
4Weight of moving object
If substrate density is reduced to decrease weight, then substrate weight decreases, but substrate life decreases
Solution Approach 1:
The substrate structure is optimized locally with appropriate fiber densities - denser regions in high deposition zones to extend substrate life through higher carbon loading capacity, and less dense regions in low deposition zones to reduce overall weight, resolving the contradiction between weight reduction and substrate life extension.
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 approach reduces soot formation, increases carbon loading capacity, and decreases the weight and volume of substrates required, enhancing the efficiency of oxygen recovery and maintaining air quality in resource-limited environments.
Implementation Method 1
fibrous substrates for collecting carbon produced during pyrolysis of hydrocarbons
Implementation Method 2
a pyrolysis reactor is configured to generate both hydrogen gas and solid carbon from one or more hydrocarbons, such as methane, through pyrolysis
Data Source
AI summary
The disclosure describes a system for generating hydrogen gas from a hydrocarbon through pyrolysis with reduced soot formation and increased carbon loading. The system includes a pyrolysis reactor configured to generate the hydrogen gas from the hydrocarbon through pyrolysis. The pyrolysis reactor includes one or more fibrous substrates configured to provide a deposition surface for carbon generated from the pyrolysis of the hydrocarbon. Each fibrous substrate has an effective void fraction between 40% and 95%, and includes a plurality of fibers configured to maintain chemical and structural stability between about 850° C. and about 1300° C. The one or more fibrous substrates may have a relatively high surface area to fiber volume of the plurality of fibers.