Three-Compartment Electrochemical Cell for In-Situ CO2 Reduction
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Solution Overview
Problem
Current carbon dioxide reduction technologies are inefficient and costly due to the need for multiple sequential steps, including carbon dioxide capture, purification, and regeneration of solvents, which require high energy consumption and result in low product concentration and expensive product separation.
Innovation Solution
A three-compartment electrochemical cell is used to reduce carbon dioxide directly from a carbon dioxide-rich absorbent, allowing in-situ extraction of high-value carboxylic acids like formic acid and oxalic acid without the need for concentration or purification of the carbon dioxide feed, and simplifies the regeneration of the absorbent, thereby reducing processing costs and energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multiple sequential steps (capture, purification, regeneration) are used for carbon dioxide reduction, then carbon dioxide can be converted to high value-added products, but energy consumption increases and process complexity increases
Solution Approach 1:
The patent combines carbon dioxide capture, electrochemical reduction, and product extraction into a single integrated electrochemical cell system. The absorbent solution flows through multiple compartments (anode compartment, product compartment, cathode compartment) where carbon dioxide is captured and simultaneously reduced to formic acid or other carboxylic acids, eliminating the need for separate capture and purification steps.
Solution Approach 2:
The electrochemical cell serves multiple functions simultaneously: it acts as a carbon dioxide capture unit, an electrochemical reactor for reduction, and an in-situ extraction system for product separation. The absorbent solution performs dual roles as both carbon dioxide carrier and reaction medium throughout the process.
2Productivity
If multiple sequential steps including solvent regeneration with heat application are used, then carbon dioxide capture and conversion can be achieved, but process complexity and equipment requirements increase
Solution Approach 1:
The patent merges the electrochemical reduction reactor and absorbent regeneration system into a single integrated cell. The electrochemical reactions at the electrodes simultaneously drive carbon dioxide reduction and facilitate absorbent regeneration, eliminating the need for separate thermal regeneration equipment and reducing overall system complexity.
Solution Approach 2:
The patent replaces thermal processing (heat application for solvent regeneration) with electrochemical processing. Instead of using external heat to regenerate the absorbent, the system uses electrical energy to drive electrochemical reactions that simultaneously reduce carbon dioxide and regenerate the absorbent solution in-situ within the cell.
3Ease of operation
If low concentration carbon dioxide absorbent is used, then carbon dioxide capture can be performed, but reaction kinetics are slow and product concentration is low leading to expensive separation
Solution Approach 1:
The patent changes the concentration parameter of the absorbent solution, using high concentration absorbent (30-50 wt% for monoethanolamine, 25-35 wt% for diethanolamine, or 30-50 wt% for diisopropanolamine) to achieve faster reaction kinetics and higher product concentration, thereby improving both reaction rate and ease of product separation.
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 method enables a cost and energy-efficient electrochemical reduction of carbon dioxide to high-value chemical compounds with continuous in-situ extraction, eliminating the need for separate capture and purification steps, thus enhancing the economic viability and efficiency of the process.
Implementation Method 1
applying an electrical potential between an anode and a cathode in the electrochemical cell sufficient for the cathode to reduce carbon dioxide into a reduced carbon dioxide product or product mixture
Implementation Method 2
collecting reduced carbon dioxide product or product mixture via in-situ extraction into an acidic environment
Data Source
AI summary
The disclosure is directed to a method for in-situ extracting a reduced carbon dioxide product or product mixture in an electrochemical cell, and the use of a three-compartment electrochemical cell for in-situ extraction of organic carboxylic acids such as formic acid, acetic acid, oxalic acid, glycolic acid, tartaric acid, malonic acid, propionic acid, glyoxylic acid, and/or salts thereof.