Method for recovering an ethylene stream from a carbon monoxide rich feed stream

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Solution Overview

Problem

Current methods for recovering ethylene from unconventional sources with high carbon monoxide content are inefficient, resulting in low yields and recovery rates, and require complex equipment such as multiple distillation columns.

Innovation Solution

A process involving a processing unit to purify the feed stream, a carbon monoxide elimination assembly using pressure swing adsorption, and a single distillation column to achieve high ethylene recovery and purity, with a simplified setup that includes a washing tower, molecular sieves for drying, and a distillation column with reboiling capability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional methods are used to recover ethylene from feed streams with high carbon monoxide content, then the recovery process can be implemented, but the recovery rate and purity are low

Engineering Contradiction:
Improveethylene purityVSAvoidethylene recovery rate
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The invention changes the operating parameters of the distillation column, specifically operating at a pressure of 10-40 bar and with a reboiler temperature of 100-200°C, which allows for high recovery rates (>99%) and purity (>99.5%) of ethylene from feed streams containing high carbon monoxide content (20-80%)

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention segments the separation process into distinct functional units: a processing unit for preliminary treatment, a carbon monoxide elimination assembly using pressure swing adsorption, and a distillation column for final purification. This segmentation allows each unit to optimize for its specific function, achieving both high recovery and purity

Inventive Principle:
Principle #1Segmentation

2Manufacturing precision

If multiple distillation columns are used to recover ethylene from unconventional sources, then ethylene purity can be improved, but the equipment complexity increases

Engineering Contradiction:
Improveethylene purityVSAvoidnumber of distillation columns
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention merges the carbon monoxide elimination function and ethylene purification function into a single integrated distillation column system. The column is designed with specific internal configurations (trays or packing, reboiler, condenser) that allow it to perform both CO removal and ethylene purification in one unit, achieving >99.5% purity without requiring multiple separate columns

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The distillation column is designed as a multi-functional unit that simultaneously eliminates carbon monoxide and purifies ethylene. The column can handle feed streams with varying CO content (20-80%) and consistently produce high-purity ethylene, making it a universal solution for unconventional ethylene sources

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Device complexity

If a single distillation column is used to recover ethylene from high carbon monoxide feed streams, then the equipment complexity is reduced, but the recovery rate and purity decrease

Engineering Contradiction:
Improvenumber of distillation columnsVSAvoidethylene purity
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The invention introduces a carbon monoxide elimination assembly using pressure swing adsorption as an intermediary unit before the distillation column. This intermediary removes the bulk of carbon monoxide from the feed stream, allowing the single distillation column to focus on final purification and achieve >99.5% ethylene purity without requiring multiple columns

Inventive Principle:
Principle #24Intermediary (Mediator)

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 achieves ethylene recovery rates greater than 99% and purity greater than 99.5%, making it suitable for polymer production without the need for additional distillation, using a straightforward and economical approach.

Implementation Method 1

a carbon monoxide elimination assembly (22) intended to eliminate the carbon monoxide contained in the intermediate stream (20)

Methodology Applied
Scientific EffectPressure swing adsorption: Pressure Swing Adsorption

Implementation Method 2

a set (18) for distillation of the stream of treated gas (70) to form an ethylene-rich stream

Methodology Applied
Scientific EffectDistillation: Distillation

Implementation Method 3

an assembly (16) for cooling and at least partial condensation of a treated gas (70) obtained from the feed stream

Methodology Applied
Scientific EffectCondensation: Condensation

Data Source

PatentEP3013924B1Method for recovering an ethylene stream from a carbon monoxide rich feed stream
Publication Date: 2019.12.11 TECH FRANCE SA
  • EP3013924B1 patent drawingFigure 1
  • EP3013924B1 patent drawingFigure 2~4
  • EP3013924B1 patent drawingFigure 5

AI summary

The method according to the invention comprises the following steps: - treating a feed stream (12) to obtain a treated gas stream (60); - cooling the treated gas stream (60) in a heat exchanger (34) to form at least one column feed fraction; - introducing each column feed fraction into a distillation column (50); - heating at least one downstream flow (106) coming from the head stream (104) of the column in the heat exchanger (34). The treatment step comprises the formation of an intermediate stream (20) comprising at least 20 mol% of ethylene and at least 20 mol% of carbon monoxide, the method comprising a step for eliminating the carbon monoxide contained in the intermediate stream (20).