Pressure Swing Reforming Reactor for High-Pressure Hydrogen
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Solution Overview
Problem
The steam reforming process for hydrogen production is limited by low efficiency and large volume occupancy, requiring high-temperature furnaces that are not economically attractive due to low productivity and inefficient heat utilization.
Innovation Solution
Integrating pressure swing reforming with the water gas shift reaction and hydrogen separation under high pressures, allowing for improved thermal efficiency and high-pressure hydrogen production, while recycling flue gas to reduce air and oxygen usage in the regeneration phase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If steam reforming is carried out in large furnaces with catalyst packed into tubes, then the reaction can proceed at high temperatures, but the furnaces occupy very large volumes of space resulting in low productivity
Solution Approach 1:
The reforming process is divided into multiple sequential zones (first zone for reforming, second zone for cooling, third zone for reheat) within a single reactor vessel. This segmentation allows the system to achieve high temperatures for reforming while maintaining a compact overall footprint, as each zone performs a specific function and the zones are arranged in series rather than requiring large furnace volumes.
Solution Approach 2:
The system employs periodic cycling between reforming operation and regeneration phases. During regeneration, the reactor is isolated and reheat gas is introduced to restore catalyst activity. This periodic action allows the same reactor volume to be used continuously for high-temperature reforming without requiring larger furnaces, thereby maintaining high productivity per unit volume.
2Stress or pressure
If steam reforming furnaces are designed to withstand high pressure, then synthesis gas can be produced at useful pressures, but the furnace volume must be large to accommodate the high-temperature reaction zones
Solution Approach 1:
Multiple functional zones (reforming, cooling, reheat) are merged into a single integrated reactor vessel that operates at high pressure throughout. This eliminates the need for separate low-pressure and high-pressure vessels and interconnectors, reducing the overall stationary volume while maintaining high synthesis gas pressure. The compact high-pressure design is achieved by combining functions that would traditionally require separate equipment.
3Loss of energy
If the reforming process is made more efficient through heat recovery, then thermal efficiency improves, but the device complexity increases due to additional heat exchange equipment
Solution Approach 1:
The cooling zone is nested within the reactor structure, with cooling channels arranged concentrically around the reforming catalyst beds. This nested arrangement allows heat recovery to occur within the same reactor volume without requiring external heat exchangers, thereby improving thermal efficiency while minimizing additional equipment and maintaining structural compactness.
4Stress or pressure
If pressure swing reforming is used to produce high-pressure synthesis gas, then compressor requirements are reduced, but the process complexity increases due to pressure cycling operations
Solution Approach 1:
The system uses its own product synthesis gas as the reheat gas during regeneration cycles. This self-service approach eliminates the need for external fuel gases or additional heating utilities, simplifying the pressure cycling operation. The synthesis gas circulates through the reactor, absorbing heat during cooling and then reheat, automatically providing the temperature control needed for pressure swing operation without external complexity.
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 enhances thermal efficiency and productivity, enabling the production of high-pressure hydrogen with reduced space requirements, thus improving the economic attractiveness of the process.
Implementation Method 1
the reforming step involves preheating a first zone to a temperature in the range of about 700° C. to 2000° C. and then introducing a 20° C. to 600° C. hydrocarbon-containing feed, along with steam and optionally CO2 to the inlet of the first zone. Upon introduction of the reactants, the hydrocarbon is reformed into synthesis gas
Implementation Method 2
The synthesis gas is then passed from the first zone to a second zone, where the gas is cooled to a temperature close to the inlet temperature of the hydrocarbon feed
Implementation Method 3
an oxygen-containing gas and fuel are combusted near the interface of the two zones, producing a hot flue gas that travels across the first zone, thus re-heating that zone to a temperature high enough to reform the feed
Data Source
AI summary
The invention provides a method for generating high pressure hydrogen at improved thermal efficiencies. First a synthesis gas stream at a first pressure is produced in a pressure swing reformer. Next the synthesis gas stream is subjected to a high temperature water gas shift process to produce a hydrogen enriched stream from which high pressure hydrogen is obtained. Specific embodiments of the invention involve: regenerating the reformer at a pressure lower than the synthesis gas generation; operating the synthesis gas generation step at conditions sufficient to provide a syn gas stream at a temperature in the range used in the water gas shift reaction; and using pressure swing adsorption to separate the hydrogen.