CO2 Electrolysis Apparatus with Anode Gas Recycling
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Solution Overview
Problem
Current carbon dioxide conversion methods through electrolysis produce gases containing unreacted CO2, O2, and CO, leading to reduced CO2 emission reduction and lower effective usability of CO2, as the emitted purge gas contains these by-products, which hampers the reduction of CO2 emissions and utilization.
Innovation Solution
A carbon dioxide conversion apparatus comprising a CO2 supply part, CO2 electrolysis part, CO purification part, CO2 capture part, and oxidation part, which captures and purifies CO2 from anode chamber gases, reacts residual CO with captured CO2 and O2 to convert CO back to CO2, thereby reducing O2 concentration and enhancing CO2 usability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If CO2 electrolysis is performed to produce CO and H2, then CO and H2 are obtained as main products, but unreacted CO2 and by-produced CO2 remain in the gas mixture, reducing CO2 emission reduction effectiveness
Solution Approach 1:
The patent recovers unreacted CO2 from the gas mixture produced in CO2 electrolysis by passing it through a basic solution (NaOH or KOH), which absorbs CO2 to form carbonate or bicarbonate salts. The CO2 is then recovered by acidifying the basic solution and heating to release pure CO2, which can be reused in the electrolysis process. This closes the CO2 cycle and eliminates CO2 emissions.
Solution Approach 2:
The patent creates a multi-functional system where the same CO2 supply unit can both supply CO2 to the electrolysis cell and receive/recycle CO2 from the gas purification process. The CO2 circulation system integrates multiple functions: gas absorption, CO2 release, purification, and reuse, making the system more efficient and environmentally friendly.
2Measurement precision
If purge gas is emitted after purifying CO and H2, then active ingredients are captured, but O2 and residual CO2 are emitted, lowering effective usability of CO2
Solution Approach 1:
Instead of discarding the purge gas containing O2 and residual CO2, the patent recovers CO2 by absorbing it in a basic solution. The recovered CO2 is then reused in the electrolysis process, transforming waste into a valuable resource and improving CO2 usability.
Solution Approach 2:
The patent converts the harmful aspect of emitting CO2 and O2 in the purge gas into a benefit by using the basic solution to absorb CO2, which is then recovered and reused. What was previously waste (CO2 in purge gas) becomes a valuable input for the electrolysis process.
3Quantity of substance
If O2 is present in the CO2 gas stream, then CO2 is available for reuse, but O2 degrades the cathode electrode, reducing system reliability
Solution Approach 1:
The patent removes O2 from the CO2 gas stream by passing it through a reducing gas (H2 or CO) in a reaction process. The O2 reacts with the reducing gas to form H2O or CO2, effectively extracting O2 from the mixture and protecting the cathode electrode from degradation while maintaining CO2 availability for reuse.
Solution Approach 2:
The patent introduces a reducing gas (H2 or CO) as an intermediary substance to remove O2 from the CO2 stream. This intermediary reacts with O2 to form harmless products, protecting the cathode electrode while allowing CO2 to be reused in the electrolysis process.
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 apparatus effectively reduces O2 concentration in the CO2 gas stream, preventing O2 degradation of the cathode electrode and allowing for the reuse of CO2 in the electrolysis process, thereby increasing the effective usability of CO2 and reducing CO2 emissions.
Implementation Method 1
a cathode chamber configured to receive the carbon dioxide from the carbon dioxide supply part and reduce the carbon dioxide to produce carbon monoxide
Implementation Method 2
an anode chamber configured to oxidize an oxidizable substance to produce oxygen and carbon dioxide
Implementation Method 3
an oxidation part configured to perform a reaction between a reducing gas and a carbon dioxide containing gas, the reducing gas being discharged from the carbon monoxide purification part and containing a residual carbon monoxide, and the carbon dioxide containing gas being separated and captured in the carbon dioxide capture part and containing a residual oxygen
Data Source
AI summary
A carbon dioxide conversion apparatus 1 includes: a carbon dioxide electrolysis part 3 that includes: a cathode chamber 8 to reduce carbon dioxide to produce carbon monoxide; and an anode chamber 9 to oxidize an oxidizable substance to produce oxygen and carbon dioxide; a carbon dioxide capture part 5 to separate and capture the carbon dioxide from an oxygen-carbon dioxide containing gas produced in the anode chamber 9; a carbon monoxide purification part 4 to purify the carbon monoxide in a carbon monoxide containing gas produced in the cathode chamber 8; and an oxidation part 6 to perform a reaction between a reducing gas and a carbon dioxide containing gas, the reducing gas containing a residual carbon monoxide discharged from the carbon monoxide purification part 4, and the carbon dioxide containing gas being separated and captured in the carbon dioxide capture part 5 and containing a residual oxygen.