Compact Pressure Swing Reformer with Rotary Valves
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Solution Overview
Problem
Current hydrogen production methods for fuel cell vehicles face challenges in providing a compact and cost-effective means to generate pure hydrogen on-board, as conventional methods require high-pressure storage or complex systems, and existing reformers are inefficient and costly.
Innovation Solution
The use of a compact, multi-bed pressure swing reformer with high temperature rotary valves and direct liquid injection, which enables efficient hydrogen production by preserving syngas through pressure equalization and reducing steam usage, and employs a rotary valve system to manage high temperature and pressure conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional hydrogen storage methods are used (high-pressure compressed gas, cryogenic liquid, or solid alloys), then hydrogen can be stored on-board, but the system becomes heavy, expensive, and complex
Solution Approach 1:
The reformer system generates hydrogen on-board by converting liquid hydrocarbon fuels (such as gasoline or diesel) into hydrogen through reforming reactions, eliminating the need for external hydrogen storage systems. The system serves itself by producing its own fuel from readily available liquid fuels, thereby reducing system complexity and cost while maintaining adequate hydrogen supply for fuel cell operation
Solution Approach 2:
The invention employs pressure swing reforming that utilizes cyclic pressure variations (between approximately 1-10 atm) to drive the reforming process and separate hydrogen from the reformate stream. By dynamically changing pressure parameters during operation, the system achieves efficient hydrogen production and separation without requiring complex storage infrastructure, thus resolving the contradiction between hydrogen quantity and system complexity
2Volume of moving object
If a compact reformer is designed to reduce system size, then on-board hydrogen generation becomes feasible, but maintaining sufficient catalyst temperature for effective reforming becomes difficult
Solution Approach 1:
The pressure swing reformer operates through periodic cycles of pressurization and depressurization, during which the catalyst bed temperature is dynamically controlled. The cyclic pressure changes enable alternating endothermic reforming and exothermic combustion phases, allowing the compact catalyst bed to achieve and maintain the necessary temperatures (>700°C) for effective reforming reactions despite the reduced system size. This periodic operation resolves the contradiction between compact size and sufficient temperature maintenance
3Productivity
If steam is used to push syngas out of reformer beds to enhance recovery, then hydrogen production efficiency improves, but water/steam demand increases
Solution Approach 1:
The pressure swing reforming process recovers syngas through pressure equalization between beds during the pressure swing cycles, eliminating the need for additional steam to push syngas out of the beds. The system discards the conventional steam push step and recovers syngas by utilizing the pressure differential naturally created during bed depressurization and the heat of compression, thereby maintaining high hydrogen production efficiency while significantly reducing water/steam consumption
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 solution increases hydrogen production efficiency, reduces system size and cost, and achieves high purity hydrogen with reduced water and steam demand, while maintaining peak catalyst temperatures for effective conversion.
Implementation Method 1
pressure equalizations may be used (in which high pressure gases released from beds which have completed the reforming stage are used to pressurize beds which have completed the regeneration stage)
Implementation Method 2
employs a rotary valve system to manage high temperature and pressure conditions
Implementation Method 3
reacting the hydrocarbon fuel with steam and/or with air or oxygen-enriched air, to produce a syngas stream, which contains hydrogen
Implementation Method 4
maintaining peak catalyst temperatures for effective conversion
Implementation Method 5
the catalyst bed temperature is hot enough to accomplish the reforming reaction (e.g. >1000°C)
Data Source
AI summary
Embodiments of a compact pressure swing reformer are disclosed. Certain embodiments have a construction comprising multiple rotating reformer beds, high temperature rotary valves at the bed ends, and E-seals to seal the beds to the valves. Several possible designs for introducing reactants into the beds also are disclosed. The multiple reformer beds are configured to provide for pressure equalization and ‘steam push’. The compact pressure swing reformer is suitable for use in fuel cell vehicle applications.