Vertical Electrolysis Cell for Industrial CO2 Reduction
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Solution Overview
Problem
Current industrial processes for the electrochemical reduction of CO2 to produce CO or CO/H2 mixtures face challenges in scaling up due to limitations in construction height and pressure differences between gas and electrolyte spaces in gas diffusion electrodes, leading to inefficient operation and limited production capacity.
Innovation Solution
An electrolysis cell design featuring a gas diffusion electrode with a cathode and anode arranged vertically, utilizing an ion exchange membrane or diaphragm separator, and a falling liquid film principle to maintain the catholyte gap, preventing permeation and allowing for increased construction height and efficient operation at industrial scales.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the construction height of the electrolysis cell is increased to achieve industrial scale production, then the production capacity is improved, but the pressure difference between gas and electrolyte spaces causes gas breakthrough or electrolyte flooding that destroys GDE function
Solution Approach 1:
The patent transitions from horizontal to vertical electrode arrangement, changing the spatial dimension of the electrolysis cell. This vertical configuration allows the GDE to be positioned at the bottom with electrolyte flowing downward under gravity, enabling taller construction heights while maintaining pressure balance and preventing gas breakthrough or electrolyte flooding that would occur in horizontal configurations.
Solution Approach 2:
The patent employs hydrodynamic principles by allowing electrolyte to flow downward under gravity in the vertical configuration. This hydraulic approach uses the weight of the electrolyte column to naturally balance the gas pressure, eliminating the need for complex pressure control systems and enabling stable operation at industrial scale heights.
2Productivity
If the electrode area is increased to achieve industrial production amounts, then the productivity is improved, but the pressure management becomes difficult leading to GDE failure
Solution Approach 1:
By arranging electrodes vertically and positioning the GDE at the bottom, the patent enables tall, large-area cells without increasing pressure management complexity. The vertical orientation allows gravity to naturally manage electrolyte pressure, scaling to industrial dimensions without proportionally increasing system complexity.
Solution Approach 2:
The vertical configuration allows the electrolyte to self-regulate pressure through its own weight under gravity. This self-balancing mechanism eliminates the need for external pressure control systems, enabling large-scale operation without proportional increases in device complexity.
3Productivity
If the gas-side pressure is increased to improve reaction efficiency, then the CO2 supply is improved, but the gas breaks through the GDE and destroys its function
Solution Approach 1:
The vertical arrangement with GDE at the bottom allows the electrolyte to exert downward pressure under gravity, naturally counterbalancing gas pressure. This enables higher gas-side pressures for improved reaction efficiency without gas breakthrough, as the electrolyte column weight provides automatic pressure compensation.
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 design enables the electrochemical reduction of CO2 at industrial scales, achieving higher production capacities and maintaining the integrity of the gas diffusion electrode, thus overcoming previous limitations in construction height and pressure management.
Implementation Method 1
The internal structure of the GDE has to make it possible for the reaction of the gas to occur at the three-phase boundary between electrolyte, catalyst and gas as close as possible to the electrolyte. This boundary layer is stabilized by the hydrophobicity of the GDE material. However, it is found that this stabilization, which is brought about by the surface tension of the electrolyte at the electrode surface, permits only a finite pressure gradient between gas side and liquid side of the GDE.
Implementation Method 2
a gap for passage of the catholyte according to the principle of a falling liquid film is arranged between separator and cathode
Implementation Method 3
an ion exchange membrane or a diaphragm, with the separator particularly preferably being an ion exchange membrane
Implementation Method 4
The electrochemical reaction of CO2 in an electrolysis cell preferably occurs at a gas diffusion electrode which is connected as cathode and can in principle be carried out according to the reaction indicated below by way of illustration: CO2+H2O+2e−→CO+2 OH−
Data Source
AI summary
The invention relates to an electrolysis cell, an electrolyzer and to a method for the electrochemical reduction of carbon dioxide on an industrial scale.