Method and system for separation of a hydrocarbon mixture

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Current methods for separating hydrocarbon mixtures, such as those produced by steam cracking, are complex and require significant instrumentation and safety efforts due to the use of C3 absorbers and intercoolers in deethanization and demethanization processes, which increase operational complexity and costs.

Innovation Solution

A method that involves partial condensation of the gas mixture at specific temperature and pressure levels to separate hydrocarbons, eliminating the need for C3 absorbers by using purely condensative processes, followed by rectification to achieve high purity fractions of hydrogen, methane, and hydrocarbons with two or more carbon atoms, reducing the complexity and instrumentation required.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If C3 absorber and intercooler are used in deethanization and demethanization processes, then separation effectiveness is improved, but device complexity and instrumentation requirements increase

Engineering Contradiction:
Improveseparation effectivenessVSAvoiddevice complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent extracts and removes the C3 absorber and intercooler from the traditional separation sequence, replacing them with a simplified two-column process (depropanizer followed by deethanizer) that achieves the same separation effectiveness without the additional complexity of these units

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent inverts the traditional separation sequence by performing depropanization before deethanization, rather than the conventional approach of deethanization first. This reversal eliminates the need for C3 absorber and intercooler units while maintaining separation effectiveness

Inventive Principle:
Principle #13The other way round (Inversion)

2Manufacturing precision

If C3 absorber and intercooler are used in deethanization and demethanization processes, then separation effectiveness is improved, but operational costs increase

Engineering Contradiction:
Improveseparation effectivenessVSAvoidoperational costs
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent extracts and removes the C3 absorber and intercooler from the traditional separation sequence, replacing them with a simplified two-column process (depropanizer followed by deethanizer) that achieves the same separation effectiveness without the additional complexity of these units

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent inverts the traditional separation sequence by performing depropanization before deethanization, rather than the conventional approach of deethanization first. This reversal eliminates the need for C3 absorber and intercooler units while maintaining separation effectiveness

Inventive Principle:
Principle #13The other way round (Inversion)

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 simplifies the deethanization and demethanization processes, reducing the separation effort by over 60%, lowering capital and operating costs, and minimizing fouling, while maintaining high energy efficiency and product purity.

Implementation Method 1

partial condensation of the gas mixture at specific temperature and pressure levels to separate hydrocarbons

Methodology Applied
Scientific EffectPartial condensation: Condensation

Implementation Method 2

A method that involves partial condensation of the gas mixture at specific temperature and pressure levels

Methodology Applied
Scientific EffectCooling: Cooling

Data Source

PatentEP3775735B1Method and system for separation of a hydrocarbon mixture
Publication Date: 2023.12.27 LINDE AG
  • EP3775735B1 patent drawingFigure 1
  • EP3775735B1 patent drawingFigure 2
  • EP3775735B1 patent drawingFigure 3

AI summary

The invention relates to a process for separating a component mixture (K) which contains hydrogen, methane, hydrocarbons having two carbon atoms and hydrocarbons having three or more carbon atoms, wherein in a deethanization at least one portion of the component mixture (K) is subjected to a first partial condensation by cooling from a first temperature level to a second temperature level at a first pressure level to obtain a first gas fraction (G1) and a first liquid fraction (C1), at least one portion of the gas fraction (G1) is subjected to a second partial condensation by cooling from the second temperature level to a third temperature level at the first pressure level to obtain a second gas fraction (G4) and a second liquid fraction (C2) and at least a portion of the first liquid fraction (C1) and at least a portion of the second liquid fraction (C1) are subjected to a rectification to obtain a third gas fraction (G3) and a third liquid fraction (C3+). The first liquid fraction (C1) or the portion thereof subjected to the rectification and the second liquid fraction (C2) or the portion thereof subjected to the rectification are decompressed to a second pressure level and the rectification is performed at the second pressure level, wherein the first pressure level is 25 to 35 bar and the second pressure level is 14 to 17 bar. A tops gas formed during the rectification is cooled to -25°C to -35°C and thus partially condensed, wherein a condensed proportion of the tops gas is in part or in whole used in the rectification as reflux and a non-condensed proportion of the tops gas is in part or in whole provided as the third gas fraction (G3). The present invention likewise provides a corresponding plant (100, 200).