Integrated EO Process Without Ethylene-Ethane Separation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The production of ethylene oxide (EO) through ethane oxidative dehydrogenation and subsequent ethylene epoxidation faces challenges due to the high capital and operational costs associated with separating unconverted ethane and ethylene streams, which are typically achieved through cryogenic distillation, making the process economically unfeasible.
Innovation Solution
A process integrating oxidative dehydrogenation (ODH) and ethylene epoxidation (EO) reactors, where the unreacted effluent from the EO reactor is recycled to both reactors without separating ethylene from ethane, and oxygen is recycled back, allowing for low ethane concentrations in the EO reactor feed, thereby enhancing carbon and capital efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If cryogenic distillation is used to separate unconverted ethane and ethylene streams, then separation purity is improved, but capital cost and operational cost increase significantly
Solution Approach 1:
The patent extracts and removes the separation step from the process by directing the combined stream containing unconverted ethane and ethylene directly to the epoxidation reactor. This eliminates the need for cryogenic distillation infrastructure, thereby reducing capital cost while maintaining product purity through selective chemical reaction.
Solution Approach 2:
The patent merges the effluent stream from the ODH reactor with fresh ethane feed and directs the combined stream directly to the epoxidation reactor without intermediate separation. This integration eliminates the separation unit and reduces overall process complexity and capital investment.
2Manufacturing precision
If cryogenic distillation is used to separate unconverted ethane and ethylene streams, then separation purity is improved, but operational cost increases significantly
Solution Approach 1:
The patent extracts and removes the energy-intensive separation step from the process by directing the combined stream containing unconverted ethane and ethylene directly to the epoxidation reactor. This eliminates the need for cryogenic distillation operations, thereby reducing operational costs associated with refrigeration and distillation.
Solution Approach 2:
The patent merges the effluent stream from the ODH reactor with fresh ethane feed and directs the combined stream directly to the epoxidation reactor without intermediate separation. This integration eliminates the separation unit and reduces overall operational costs.
3Productivity
If ethane steam cracking is used for ethylene production, then ethylene is produced, but capital intensity and incomplete selectivity are issues
Solution Approach 1:
The patent changes the fundamental reaction parameters by using oxidative dehydrogenation instead of steam cracking. This alternative reaction pathway achieves ethylene production with different selectivity characteristics and eliminates the need for subsequent separation and purification steps, thereby reducing capital intensity.
Solution Approach 2:
The patent performs preliminary oxidation during the ethane conversion step itself, converting unreacted ethane to ethylene in situ before the epoxidation stage. This preliminary action eliminates the need for separate steam cracking and separation units, reducing overall capital intensity.
4Manufacturing precision
If separation of ethylene-ethane streams is implemented, then product purity is improved, but process complexity increases
Solution Approach 1:
The patent extracts and removes the separation step from the process by directing the combined stream containing unconverted ethane and ethylene directly to the epoxidation reactor. This eliminates the need for cryogenic distillation infrastructure, thereby reducing capital cost while maintaining product purity through selective chemical reaction.
Solution Approach 2:
The patent merges the effluent stream from the ODH reactor with fresh ethane feed and directs the combined stream directly to the epoxidation reactor without intermediate separation. This integration eliminates the separation unit and reduces overall process complexity.
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 integrated process achieves higher overall carbon efficiency and lower capital intensity by eliminating the need for costly ethylene-ethane separation and oxygen recycling, leading to improved ethylene oxide production efficiency.
Implementation Method 1
using (i) a first catalytic reactor (e.g., oxidative dehydrogenation (ODH) reactor) for converting ethane to ethylene by ODH
Implementation Method 2
a second catalytic reactor (e.g., EO reactor) for converting ethylene to EO
Data Source
AI summary
An ethylene oxide (EO) production process comprising (a) introducing a first reactant mixture (C2H6, C2H4, O2) to a first reactor to produce a first effluent stream (C2H4, C2H6, O2), wherein the mole fraction of ethylene in first effluent stream is greater than in first reactant mixture; wherein the first reactant mixture is characterized by a molar ratio of ethylene to ethane of ≥1.3; (b) introducing the first effluent stream to a second reactor to produce a second effluent stream (EO, C2H4, C2H6, O2); (c) separating the second effluent stream into an EO product stream (EO) and recycle stream (C2H4, C2H6, O2); wherein ethylene is not separated from recycle stream and/or first effluent stream; and (d) recycling at least a portion of recycle stream to the first reactor, and a portion of recycle stream to the second reactor.