CO Electrolyzer with RWGS Reactor for CO2 Conversion
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Solution Overview
Problem
Current carbon dioxide electrolysis processes face challenges such as high energy consumption and reduced efficiency due to the 'carbonate problem', which involves the reaction of carbon dioxide with alkaline equivalents, leading to pH changes and component degradation, and the lack of sustainable sources for carbon monoxide in carbon monoxide electrolyzers.
Innovation Solution
A system integrating a reverse water gas shift (RWGS) reactor with a carbon monoxide electrolyzer, where carbon dioxide is converted to carbon monoxide, which is then used in a low-temperature electrolysis process to produce valuable chemicals like hydrocarbons, olefins, and alcohols, avoiding the carbonate problem and utilizing a novel dihydrogen recirculation system to optimize energy use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If carbon dioxide electrolysis is operated in highly alkaline electrolyte to minimize energy consumption, then energy efficiency is improved, but carbonate problem occurs leading to pH changes and component degradation
Solution Approach 1:
The system is divided into two separate electrolyzers: a first electrolyzer that produces carbon monoxide from carbon dioxide, and a second electrolyzer that produces valuable chemicals from the carbon monoxide. This segmentation allows each electrolyzer to operate under optimized conditions independently, preventing the carbonate problem from affecting the overall system reliability while maintaining energy efficiency.
Solution Approach 2:
Carbon monoxide serves as an intermediary substance between carbon dioxide and the final valuable chemical products. By converting carbon dioxide to carbon monoxide in the first electrolyzer and then using this intermediate in the second electrolyzer, the system avoids direct carbonate formation issues while maintaining the beneficial alkaline environment for energy-efficient operation.
2Productivity
If carbon dioxide is converted directly to valuable chemicals through electrolysis, then product value is improved, but energy consumption increases due to carbonate problem
Solution Approach 1:
The conversion process is segmented into two distinct electrochemical steps: first converting carbon dioxide to carbon monoxide, then converting carbon monoxide to valuable chemicals. This segmentation allows each step to operate at optimal efficiency, reducing total energy consumption while maintaining high productivity of valuable chemical products.
Solution Approach 2:
The system maintains continuous useful action by using the carbon monoxide produced in the first electrolyzer as the feedstock for the second electrolyzer. This continuous conversion chain ensures that carbon dioxide is efficiently transformed into valuable chemicals without energy losses from carbonate formation, maximizing both productivity and energy efficiency.
3Power
If alkaline equivalents are used in electrolyzer to enable efficient metallic catalysts for water oxidation, then catalytic activity is improved, but carbonate problem leads to consumption of alkaline equivalents and pH lowering
Solution Approach 1:
The system segments the electrochemical processes into two separate electrolyzers, allowing the first electrolyzer to maintain a stable alkaline environment with sufficient hydroxide ions for efficient water oxidation catalysis. The second electrolyzer then processes the carbon monoxide without requiring high concentrations of alkaline equivalents, thus preventing carbonate formation and preserving catalytic activity.
Solution Approach 2:
Carbon monoxide acts as an intermediary that decouples the water oxidation reaction from direct carbon dioxide reduction. This allows the alkaline electrolyte to function efficiently at the anode for water oxidation while the cathode processes carbon monoxide without consuming excessive hydroxide ions, maintaining stable pH and preventing carbonate problem.
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 enables cost-competitive production of sustainable chemicals, reduces greenhouse gas emissions, and lowers the overall energy demand by minimizing dihydrogen consumption and extending system lifetime, while providing a sustainable source of carbon monoxide for electrolyzers.
Implementation Method 1
A reverse water gas shift (RWGS) reactor with a carbon monoxide electrolyzer, where carbon dioxide is converted to carbon monoxide
Implementation Method 2
carbon dioxide electrolysis is a recent technological pathway to electrolyze carbon dioxide and water to carbon monoxide and other small molecules using low-carbon electricity
Data Source
AI summary
Methods and systems related to valorizing carbon dioxide are disclosed. A disclosed system includes a reverse water gas shift (RWGS) reactor, a carbon dioxide source connection fluidly connecting a carbon dioxide source to the RWGS reactor, an electrolyzer having an anode area and a cathode area, and a carbon monoxide source connection fluidly connecting the RWGS reactor to the cathode area. The RWGS reactor is configured to generate, using a volume of carbon dioxide from the carbon dioxide source connection, a volume of carbon monoxide in a RWGS reaction. The electrolyzer is configured to generate, using the electrolyzer and a reduction of the volume of carbon monoxide from the carbon monoxide source connection and an oxidation of an oxidation substrate, a volume of generated chemicals including hydrocarbons, organic acids, alcohol, olefins, or N-rich organic compounds.