Ethylene Production via Ethanol Loop to Avoid Cryogenic Separation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing processes for producing ethylene from CO2 require cumbersome or expensive separation steps, such as cryogenic distillation, to separate CO, ethylene, and H2, and are not well-suited for intermittent renewable energy sources.
Innovation Solution
An electrolyzer converts a CO-containing stream into an ethylene-containing vapor and ethanol-containing liquid stream, followed by hydration, ethanol separation, and dehydration to produce ethylene, avoiding the need for cryogenic distillation and enabling ethanol storage for continuous downstream processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If direct conversion of CO2 to ethylene using an electrolyzer is employed, then ethylene production is achieved, but separation of CO, ethylene and H2 requires cumbersome or expensive cryogenic distillation
Solution Approach 1:
The patent introduces an intermediary substance (ethanol) that mediates the conversion process. Instead of directly converting CO2 to ethylene, the process first converts CO2 to CO, then to ethanol in the electrolyzer, and finally converts ethanol to ethylene. This intermediary approach allows ethanol to be produced in a separate liquid phase that can be easily separated from the electrolyzer, avoiding the need for complex cryogenic distillation of gas-phase products.
Solution Approach 2:
The patent changes the physical state parameter of the product by producing ethanol in liquid form rather than ethylene in gas form. This parameter change from gas to liquid phase enables simple separation through condensation and decantation, eliminating the need for complex cryogenic distillation equipment while maintaining ethylene production capability through subsequent dehydration of ethanol.
2Use of energy by stationary object
If intermittent renewable power sources are used to drive the electrolyzer, then cost reduction is achieved, but continuous operation of downstream processes cannot be ensured
Solution Approach 1:
The patent performs preliminary action by producing and storing ethanol in advance when renewable energy is available. The electrolyzer converts CO2 to ethanol during periods when renewable power is generated, and the ethanol is stored in tanks for later use. This preliminary production and storage action ensures that downstream processes can continue operating continuously even when renewable energy sources are intermittent, as the stored ethanol serves as a reliable feedstock.
3Ease of manufacture
If ethanol is stored instead of using expensive batteries, then storage cost is reduced, but energy storage for continuous electrolyzer operation is limited
Solution Approach 1:
The patent extracts the energy storage function from the electrolyzer system itself and separates it into two independent components: the electrolyzer that produces ethanol, and the ethanol storage tanks that provide temporal decoupling. By taking out the energy storage function and implementing it through chemical energy storage in ethanol rather than electrical energy storage in batteries, the system achieves long-duration storage capability with low-cost infrastructure while maintaining the ability to operate downstream processes continuously.
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 process efficiently produces ethylene while eliminating the need for cryogenic distillation and allows for ethanol storage, accommodating intermittent renewable energy sources without expensive batteries.
Implementation Method 1
converting the CO-containing stream provided in step (a) in an electrolyzer thereby producing an ethylene-containing vapour stream and an ethanol-containing liquid stream
Implementation Method 2
subjecting at least a part of the ethylene-containing vapour stream obtained in step (b) to hydration thereby obtaining a first ethanol-enriched stream
Implementation Method 3
separating the first ethanol-enriched stream obtained in step (c) thereby obtaining a second ethanol-enriched stream and a water-enriched stream
Implementation Method 4
subjecting the second ethanol-enriched stream to dehydration thereby obtaining ethylene
Data Source
AI summary
The present invention provides a process for producing ethylene, the process at least comprising the steps of: (a) providing a CO-containing stream (10); (b) converting the CO-containing stream (10) provided in step (a) in an electrolyzer (2) thereby producing an ethylene-containing vapour stream (30) and an ethanol-containing liquid stream (40); (c) subjecting at least a part of the ethylene-containing vapour stream (30) obtained in step (b) to hydration thereby obtaining a first ethanol-enriched stream (90); (d) separating the first ethanol-enriched stream (90) obtained in step (c) thereby obtaining a second ethanol-enriched stream (110) and a water-enriched stream (120); and (e) subjecting the second ethanol-enriched stream (110) to dehydration thereby obtaining ethylene (140).