Membrane Separation for CO2 and Argon Removal in Ethylene Oxide Production
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Solution Overview
Problem
Conventional methods for producing ethylene oxide result in high energy consumption and loss of unreacted ethylene due to the separation of carbon dioxide and argon, which increases production costs.
Innovation Solution
A method utilizing a membrane separation unit to separate carbon dioxide and argon from unreacted ethylene, reducing energy consumption and avoiding ethylene loss, thereby improving the efficiency and cost-effectiveness of ethylene oxide production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional CO2 scrubbing with metal carbonates is used to separate carbon dioxide from unreacted ethylene, then carbon dioxide removal is achieved, but energy consumption increases due to steam regeneration of potassium carbonate
Solution Approach 1:
The patent replaces the conventional thermal regeneration process (steam heating) with a membrane-based separation system. The membrane unit physically separates CO2 from ethylene based on permeability differences, eliminating the need for energy-intensive steam regeneration of potassium carbonate while maintaining effective CO2 removal from the ethylene stream
Solution Approach 2:
The patent employs a membrane separation unit with selective permeable membranes to separate CO2 from unreacted ethylene. The thin film structure of the membrane allows selective passage of CO2 molecules while retaining ethylene, achieving efficient separation without the high energy consumption associated with conventional thermal regeneration processes
2Reliability
If argon is removed from ethylene by bleeding it off, then argon separation is achieved, but loss of unreacted ethylene occurs
Solution Approach 1:
The patent combines the separation of both argon and CO2 into a single membrane-based process. The membrane unit simultaneously removes both gases from the ethylene stream based on their permeability characteristics, eliminating the need for separate argon bleeding operations and preventing ethylene loss that would occur with conventional argon removal methods
Solution Approach 2:
The membrane separation unit performs multiple functions: it removes both CO2 and argon from the ethylene stream in a single operation. This multi-functional approach replaces the need for separate CO2 scrubbing and argon bleeding processes, maintaining separation effectiveness while preventing ethylene loss
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 membrane separation unit effectively reduces energy consumption and minimizes ethylene loss, leading to lower production costs and improved efficiency in ethylene oxide production compared to conventional methods.
Implementation Method 1
removing carbon dioxide and argon with a membrane separation unit
Data Source
AI summary
Systems and methods for producing ethylene oxide (EO) are disclosed. Ethylene oxide is produced by direct oxidizing ethylene with oxygen in a reactor. The effluent from the reactor is processed to produce (a) a product stream comprising water and ethylene oxide, (b) a reabsorber overhead stream comprising ethylene, methane, argon, and carbon dioxide, and (c) a carbonate flash gas stream comprising carbon dioxide, ethylene, methane, and water. The reabsorber overhead stream and the carbonate flash gas stream are combined to form a reclaim gas stream. The reclaimed gas stream is separated in a membrane separation unit to remove carbon dioxide and argon, forming a recycle stream comprising primarily ethylene and methane, collectively.