Ethylene Oxide Stripper Configuration for Energy Reduction

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Solution Overview

Problem

The existing ethylene oxide (EO) recovery process in integrated EO/EG processes consumes excessive energy for water evaporation and removal of impurities, leading to inefficiencies and downstream process disruptions.

Innovation Solution

The introduction of an additional unheated FA feed in the EO Stripper Concentrator stage, combined with external process streams from the EO Absorber and Residual Gas Absorber, condenses water and increases EO concentration, reducing reboiler duty and impurities in the overhead stream.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the existing EO recovery process uses a single FA feed to the EO Stripper, then the process is simple to operate, but excessive energy is consumed for water evaporation and the overhead stream contains impurities

Engineering Contradiction:
Improveenergy consumptionVSAvoidprocess complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The single FA feed stream is segmented into two separate feeds: one heated FA feed and one unheated FA feed. This segmentation allows the unheated feed to condense water vapor in the upper section of the stripper, reducing the energy burden on the reboiler while maintaining process functionality.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The unheated FA feed acts as an intermediary that condenses water vapor in the overhead stream. By introducing this intermediate stream at a lower temperature, water condensation occurs naturally, reducing the energy required for water removal without requiring additional heating or cooling equipment.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Quantity of substance

If the EO Stripper operates with high temperature to evaporate water, then water removal is effective, but energy consumption increases significantly

Engineering Contradiction:
Improvewater removal efficiencyVSAvoidenergy consumption
Core Design Contradiction:
Quantity of substanceVSUse of energy by moving object

Solution Approach 1:

Water vapor condensation is performed preliminarily by the unheated FA feed before the vapor reaches the reboiler. This preliminary condensation action reduces the amount of water that needs to be evaporated by the energy-intensive reboiler, thereby reducing overall energy consumption.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The temperature parameter of the FA feed is changed by introducing an unheated stream. This parameter change creates a temperature gradient within the stripper that promotes water condensation in the upper section, reducing the energy required for water removal.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If the EO Stripper processes all FA from the absorber, then complete EO recovery is achieved, but impurities affect downstream EG process

Engineering Contradiction:
ImproveEO recovery efficiencyVSAvoidimpurity content
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The FA feed is segmented into heated and unheated streams that are introduced at different locations in the stripper. This segmentation allows for selective condensation of water and concentration of EO in different sections, separating EO recovery from impurity removal functions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different sections of the stripper are given different local qualities: the upper section receives unheated FA for water condensation and EO concentration, while the lower section handles the heated FA for complete EO recovery. This local differentiation allows simultaneous achievement of high EO recovery and low impurity content.

Inventive Principle:
Principle #3Local quality

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 approach results in significant energy savings, reduced water content in the EO Stripper overhead, and improved purity of the EO product, minimizing downstream issues and energy consumption.

Implementation Method 1

providing one or more external process stream feeds to the EO Stripper at a location above the elevated temperature FA feed and at a lower temperature with respect to the elevated temperature FA feed thereby condensing water going up the EO Stripper

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 2

an EO Absorber and Stripper for EO recovery from absorbent by absorption in water

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Data Source

PatentEP1888194B1New stripper configuration for the production of ethylene oxide
Publication Date: 2015.11.04 SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ BV
  • EP1888194B1 patent drawingFigure 1~2
  • EP1888194B1 patent drawingFigure 3~4
  • EP1888194B1 patent drawingFigure 5~6

AI summary

Process for the recovery of ethylene oxide (EO) from fat absorbent (FA) which comprises providing a feed of elevated temperature FA to an EO Stripper, providing a stripping gas feed and contacting at elevated temperature with the elevated temperature FA feed, obtaining stripped lean absorbent (LA) and an EO- containing gas, and providing one or more external process stream feeds to the EO Stripper at a location above the elevated temperature FA feed and at a lower temperature with respect to the elevated temperature FA feed thereby concentrating EO in the E0-containing gas and/or comprising one or more impurity removal stages in the form of one or more side draws from the EO Stripper or EO Stripper Concentrator; and apparatus therefore.