Compact CO Preferential Oxidation Reactor for Marine Fuel Cells
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Solution Overview
Problem
Existing CO preferential oxidation reactors are inefficient in reducing CO concentration to low levels (5-10 ppm) in hydrogen-rich streams for fuel cells, especially in marine applications due to large volume requirements and inadequate water management, leading to suboptimal performance and space constraints.
Innovation Solution
A compact CO preferential oxidation reactor with integrated shell and tube heat exchangers and catalyst beds, utilizing pure O2 injection and static mixers to achieve efficient CO reduction, along with a drop separation device and level sensors to manage water levels and prevent water carryover, allowing operation in small volumes and varying inclinations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional CO preferential oxidation reactors are used, then CO concentration can be reduced to low levels, but the reactor occupies a large volume (more than 0.45 m³)
Solution Approach 1:
The patent combines multiple functions (heat exchange, water evaporation, CO purification) into a single integrated reactor unit. The shell and tube heat exchanger is merged with the catalyst bed, allowing simultaneous heat recovery and CO oxidation in one compact structure, thereby reducing overall reactor volume while maintaining purification effectiveness.
Solution Approach 2:
The reactor performs multiple functions simultaneously: it acts as a heat exchanger to recover thermal energy, an evaporator to generate steam, and a catalytic reactor for CO oxidation. This multi-functionality eliminates the need for separate equipment, achieving compact dimensions suitable for marine applications.
2Loss of energy
If water is used for cooling in conventional reactors, then heat exchange occurs, but water levels are not properly managed and water drops are carried over with the vapor
Solution Approach 1:
The patent incorporates level sensors that continuously monitor water levels in the evaporator section and provide feedback to the control system. This enables automatic adjustment of water flow rates to maintain optimal levels, preventing both water deficiency (which would reduce heat exchange efficiency) and water excess (which would cause carryover).
Solution Approach 2:
The patent introduces a droplet separator as an intermediary component between the evaporator and the outlet. This device removes water drops from the vapor stream before it leaves the reactor, preventing water carryover while maintaining effective heat exchange and evaporation processes.
3Productivity
If pure O2 is injected for CO oxidation, then CO reduction efficiency improves, but the risk of H2 ignition increases
Solution Approach 1:
The patent employs static mixers with specifically designed geometry to create localized mixing zones where O2 and H2-rich reformate gas are thoroughly mixed before reaching the catalyst bed. This ensures uniform distribution and controlled reaction conditions, preventing localized hot spots that could lead to H2 ignition while maintaining high CO oxidation efficiency.
Solution Approach 2:
The static mixer acts as an intermediary device that facilitates controlled mixing of O2 with the H2-rich stream. By providing a controlled mixing environment with enhanced heat and mass transfer, it ensures safe integration of pure oxygen without creating conditions for uncontrolled H2 combustion, while still achieving effective CO oxidation.
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
The reactor effectively reduces CO concentration to 5-10 ppm, enabling fuel cell operation up to 600 kW with a volume less than 0.45 m3, suitable for marine applications, while ensuring efficient water management and heat transfer across different inclinations.
Implementation Method 1
integrated with a heat exchanger that uses the heat generated in the exothermic preferential oxidation reaction for water evaporation
Implementation Method 2
heat exchanger that uses the heat generated in the exothermic preferential oxidation reaction for water evaporation
Implementation Method 3
uses the heat generated in the exothermic preferential oxidation reaction for water evaporation
Implementation Method 4
The CO preferential oxidation reactor comprises at least a first heat exchanger for cooling a gas stream with a high H2 concentration, prior to carrying out the reaction stage, by means of a water stream that is transformed into a steam stream and at least a first CO preferential oxidation reactor module having at least one catalyst bed for carrying out the purification of the gas stream
Implementation Method 5
CO preferential oxidation reactor module having at least one catalyst bed for carrying out the purification of the gas stream with a high H2 concentration, by means of a pure O2 stream
Implementation Method 6
utilizing pure O2 injection and static mixers to achieve efficient CO reduction
Implementation Method 7
a drop separation device and level sensors to manage water levels and prevent water carryover
Data Source
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AI summary
The present invention can be included in the technical field of CO preferential oxidation reactors and, more specifically, in preferential oxidation reactors that form part of an ethanol processing system for subsequently feeding a fuel cell used in naval or marine applications, which comprises at least three heat exchangers for cooling a gas stream with a high H2 concentration by means of a water stream and at least three preferential oxidation reactor modules having a catalyst bed, characterised in that the total number of tubes (15) of the heat exchangers (1, 10, 12) is integrated in a single cylindrical shell (14) and wherein an inlet manifold for the reformate gas (2) is disposed on one base of the cylindrical shell, while an oulet manifold that collects the reformate gas that flows out of the tubes and feeds it to each of the CO preferential oxidation modules (5, 11, 13) is disposed on the other base of the cylindrical shell.