Epoxidation Process With Sequential Flash Ethylene Recovery

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Solution Overview

Problem

Large ethylene oxide production plants face challenges in efficiently separating carbon dioxide and recovering ethylene for recycling due to increased amounts of byproducts and unreacted gases, leading to higher operating costs and capital expenditures.

Innovation Solution

A process involving two heat exchangers and flash drums to elevate the temperature of a rich carbonate solution, followed by sequential flashing to separate ethylene from carbon dioxide, ensuring less than 50 ppm ethylene remains in the regenerator overhead.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If larger production plants are used to increase ethylene oxide production, then productivity increases, but the complexity of separating carbon dioxide and recovering ethylene increases

Engineering Contradiction:

Improveethylene oxide production volumeVSAvoidseparation and purification system complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The separation system is divided into multiple functional units: a carbon dioxide absorber column, a flash drum for phase separation, and a regenerator column. This segmentation allows each unit to perform a specific separation function independently, making the overall system more manageable and efficient for handling large volumes of gas stream

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A carbon dioxide-absorbing solvent acts as an intermediary substance that selectively absorbs carbon dioxide from the gas stream. This intermediary enables selective separation without requiring complex physical separation equipment, simplifying the overall system while maintaining high productivity

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If larger production plants are used to increase ethylene oxide production, then productivity increases, but capital costs increase due to upsizing equipment

Engineering Contradiction:

Improveethylene oxide production volumeVSAvoidcapital expenditure on equipment

Core Design Contradiction:

ProductivityVSEase of manufacture

Solution Approach 1:

The carbon dioxide absorber column serves multiple functions: it absorbs carbon dioxide from the gas stream, separates ethylene for recycling, and handles large volume gas streams efficiently. This multi-functionality reduces the need for additional specialized equipment, thereby reducing capital costs while maintaining high productivity

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system operates at optimized temperature and pressure parameters that enhance the efficiency of the absorption and separation processes. By operating within these optimized parameter ranges, the equipment can handle larger production volumes without requiring proportional increases in equipment size, thus reducing capital expenditure

Inventive Principle:

Principle #35Parameter changes

3Productivity

If larger production plants are used to increase ethylene oxide production, then productivity increases, but operating costs increase due to greater energy consumption

Engineering Contradiction:

Improveethylene oxide production volumeVSAvoidenergy consumption for separation and purification

Core Design Contradiction:

ProductivityVSLoss of energy

Solution Approach 1:

The flash drum utilizes the inherent temperature and pressure differential of the rich carbonate solution to automatically separate liquid from gas phases without requiring external energy input. The system self-regulates the separation process, reducing energy consumption while maintaining high productivity for large-scale operations

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system exploits phase transition phenomena where the rich carbonate solution undergoes temperature and pressure changes to facilitate automatic phase separation in the flash drum. This phase transition-based separation eliminates the need for energy-intensive mechanical separation equipment, reducing operating costs while scaling production

Inventive Principle:

Principle #36Phase transitions

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 enhances ethylene recovery and recycling, reducing operating costs and minimizing waste, while avoiding capital expenditures on larger equipment.

Implementation Method 1

passing the rich carbonate solution under a pressure of between about 10 atm to about 20 atm to and through a first heat exchanger, where the temperature of the rich carbonate solution is raised to an elevated temperature

Methodology Applied

Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

dividing, in a first flash drum, the rich carbonate solution into a first flash drum overhead and a first flash liquid

Methodology Applied

Scientific EffectFlash evaporation: Flash Evaporation

Implementation Method 3

passing the rich carbonate solution under a pressure of between about 10 atm to about 20 atm

Methodology Applied

Scientific EffectPressure reduction: Depressurisation

Implementation Method 4

contacting the scrubber overheads with a carbon dioxide-absorbing solvent to form a remaining gas stream and a rich carbonate solution

Methodology Applied

Scientific EffectAbsorption: Absorption (physical)

Data Source

PatentUS20250313541A1Epoxidation process with improved ethylene separation and recovery

Publication Date: 2025.10.09 SCIENTIFIC DESIGN CO LTD

AI summary

A process for the preparation of ethylene oxide in which the efficiency of separating ethylene from carbon dioxide is improved.