Integrated RWGS and CO Electrolysis for CO2-to-Ethylene Conversion
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Solution Overview
Problem
Existing CO2 conversion methods increase the number of steps and equipment cost due to the generation of by-products like methanol and require additional energy inputs, particularly in the conversion of CO to lower olefins such as ethylene.
Innovation Solution
A CO2 conversion method that integrates a reverse water gas shift (RWGS) reaction with CO electrolysis to generate CO and H2O, followed by producing C2H4 and H2, utilizing H2 from CO electrolysis as both reactant and heat source for RWGS, thereby reducing steps and energy input.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a catalyst is used to convert CO to lower olefins, then the conversion can proceed, but by-products such as methanol are generated and the number of steps is increased
Solution Approach 1:
The invention extracts and eliminates the catalyst step from the conventional process. Instead of using a catalyst to convert CO to lower olefins, the patent directly electrolyzes CO to produce ethylene and other hydrocarbons, removing the intermediate catalytic conversion step and its associated by-products.
Solution Approach 2:
The invention replaces the chemical catalysis mechanism with an electrochemical mechanism. The electrolysis cell uses electrical energy to directly convert CO to ethylene, substituting the traditional catalyst-based chemical reaction pathway with an electrochemical pathway that avoids by-product formation.
2Productivity
If a catalyst is used to convert CO to lower olefins, then the conversion can proceed, but equipment cost is increased
Solution Approach 1:
The invention removes the expensive catalytic conversion equipment from the process flow. By using direct CO electrolysis, the patent eliminates the need for catalyst beds, reactors, and associated high-temperature processing equipment, thereby reducing overall equipment cost.
3Quantity of substance
If conventional CO2 conversion methods are used, then CO can be produced, but additional energy input is required
Solution Approach 1:
The invention merges the CO2 conversion step with the CO utilization step into a single integrated electrolysis process. The electrolysis cell simultaneously converts CO2 to CO and directly converts the generated CO to ethylene, eliminating the need for separate energy-intensive processing steps.
Solution Approach 2:
The electrolysis cell performs multiple functions: it acts as both a CO2 reduction device and a CO-to-ethylene conversion device. This multi-functional approach consolidates what would traditionally require separate energy-intensive processes into a single energy-efficient operation.
4Quantity of substance
If conventional CO2 conversion methods are used, then CO can be produced, but the number of steps is increased
Solution Approach 1:
The invention combines the CO2 to CO conversion and CO to ethylene conversion into a single electrolysis step. This merging of steps eliminates intermediate processing stages and simplifies the overall process flow from CO2 to final product.
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 efficiently converts CO from RWGS to C2H4 with reduced equipment cost and energy consumption by optimizing C2H4 current efficiency and utilizing H2 as both reactant and heat source, enabling continuous CO2 conversion without external H2 supply.
Implementation Method 1
generating CO and H2O by a RWGS reaction from CO2 and H2
Implementation Method 2
generating C2H4 and H2 by CO electrolysis from the CO and H2O
Data Source
AI summary
A CO2 conversion method includes: generating CO and H2O by a RWGS reaction from CO2 and H2; generating C2H4 and H2 by CO electrolysis from the CO and H2O; and using the H2 generated by the CO electrolysis as the H2 of the RWGS reaction.