REP Assembly Using Reverse Molten Carbonate Electrolysis
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Solution Overview
Problem
Conventional hydrogen production methods from hydrocarbon fuels are inefficient, produce excessive CO2 emissions, and require high power consumption, making them impractical for small-scale applications and non-industrial areas, especially when using steam methane reforming and low-temperature electrolysis.
Innovation Solution
A high temperature electrolyzer assembly, or reformer-electrolyzer-purifier (REP) system, that reforms and purifies hydrogen in one step by using a molten carbonate fuel cell stack operated in reverse to electrolyze CO2 and water, producing hydrogen while removing CO2 electrochemically, utilizing waste heat to drive the endothermic reforming reaction to completion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If low temperature electrolysis is used for hydrogen production from water, then hydrogen can be produced, but power consumption is excessively high
Solution Approach 1:
The patent changes the operating temperature parameter from low temperature to high temperature (700-1000°C) in the electrolyzer. This parameter change enables the use of molten carbonate electrolyte instead of aqueous electrolyte, fundamentally altering the electrolysis mechanism and reducing power consumption by 55% while maintaining hydrogen production efficiency
Solution Approach 2:
The patent replaces the conventional electrical energy input system with a hybrid system that utilizes thermal energy from waste heat sources to drive the endothermic reforming reaction. This substitution reduces the mechanical/electrical power requirement for hydrogen production
2Productivity
If steam methane reforming is used for hydrogen production from natural gas, then hydrogen can be produced, but CO2 emissions are excessive and conversion is incomplete
Solution Approach 1:
The patent converts the harmful CO2 produced during methane reforming into a useful component by feeding it back into the electrolyzer where it undergoes electrochemical reduction to produce additional hydrogen. This transforms the harmful emission into a valuable resource, reducing net CO2 emissions while increasing hydrogen production
Solution Approach 2:
The patent merges the steam methane reforming process with the electrolysis process into a single integrated system. The reformer and electrolyzer are coupled such that the reforming reaction and electrochemical reduction occur in close proximity, allowing direct utilization of reforming products and waste heat, thereby improving overall efficiency and reducing emissions
3Productivity
If conventional steam methane reformer coupled to pressure swing adsorption is used, then hydrogen can be produced, but system complexity increases and scalability to small-scale is difficult
Solution Approach 1:
The patent combines multiple functions (methane reforming, CO2 separation, and hydrogen production) into a single integrated reactor-electrolyzer unit. This merging eliminates the need for separate PSA units and complex separation systems, reducing overall system complexity while maintaining scalable hydrogen production capacity from 1 to 500,000 kg/day
Solution Approach 2:
The electrolyzer component performs multiple functions simultaneously: it conducts electrochemical reduction of CO2 to produce hydrogen, separates CO2 from the reformate stream, and utilizes waste heat from the reforming process. This multi-functionality reduces the number of separate components needed, simplifying the overall system structure
4Adaptability or versatility
If conventional hydrogen production systems are scaled down for distributed production, then local hydrogen supply is enabled, but efficiency losses increase and cost increases
Solution Approach 1:
The patent designs a modular reactor-electrolyzer system that can be segmented into multiple identical units. Each module operates independently but can be easily replicated and combined to achieve different production scales from 1 to 500,000 kg/day. This segmentation enables distributed production while maintaining constant efficiency and cost-effectiveness across all scales
Solution Approach 2:
The patent utilizes high operating temperature (700-1000°C) which enables the system to operate efficiently at small scales by utilizing waste heat from other industrial processes. This parameter change makes the system adaptable to distributed production scenarios where waste heat availability can compensate for the smaller scale of operation
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 REP system achieves efficient hydrogen production with low greenhouse emissions, reducing power consumption by 55% compared to low-temperature electrolysis, and enables scalable hydrogen generation with minimal CO2 emissions, suitable for both central and distributed production.
Implementation Method 1
using a molten carbonate fuel cell stack operated in reverse to electrolyze CO2 and water, producing hydrogen
Implementation Method 2
utilizing waste heat to drive the endothermic reforming reaction to completion
Data Source
AI summary
A high temperature electrolyzer assembly comprising at least one electrolyzer fuel cell including an anode and a cathode separated by an electrolyte matrix, and a power supply for applying a reverse voltage to the at least one electrolyzer fuel cell, wherein a gas feed comprising steam and one or more of CO2 and hydrocarbon fuel is fed to the anode of the at least one electrolyzer fuel cell, and wherein, when the power supply applies the reverse voltage to the at least one electrolyzer fuel cell, hydrogen-containing gas is generated by an electrolysis reaction in the anode of the at least one electrolyzer fuel cell and carbon dioxide is separated from the hydrogen-containing gas so that the at least one electrolyzer fuel cell outputs the hydrogen-containing gas and separately outputs an oxidant gas comprising carbon dioxide and oxygen.