Olefin Removal from Isomerization Effluent in Paraffin Separation

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Solution Overview

Problem

The challenge in steam cracking processes is the low concentration of normal paraffins in feed streams, which limits the yield of valuable ethylene and propylene, due to the presence of non-normal paraffins and aromatics that are difficult to separate and convert efficiently.

Innovation Solution

A process involving the separation of normal paraffins from non-normal paraffins using adsorption, followed by isomerization to convert non-normal paraffins into normal paraffins, with the removal of olefins from the isomerization effluent stream to enhance the concentration of normal paraffins in the feed stream for steam cracking units.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If isomerization is performed to convert non-normal paraffins to normal paraffins, then the concentration of normal paraffins increases, but olefins are produced as byproducts that must be removed

Engineering Contradiction:

Improveconcentration of normal paraffinsVSAvoidolefin byproducts

Core Design Contradiction:

Quantity of substanceVSObject-generated harmful factors

Solution Approach 1:

The patent applies extraction by removing olefins from the isomerization effluent stream through a side-cut fractionation column. The olefin-rich fraction is separated and removed from the recycle stream, preventing olefin accumulation while maintaining the beneficial effect of normal paraffin production from isomerization.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces an intermediary olefin removal unit (fractionation column) between the isomerization reactor and the adsorption separation unit. This intermediary component handles the harmful olefin byproducts, allowing the main process to continue operating efficiently without olefin interference in the adsorption separation stage.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Quantity of substance

If adsorption separation is used to separate normal paraffins from non-normal paraffins, then normal paraffin concentration increases, but the process has a limit on olefin concentration in the feed

Engineering Contradiction:

Improvenormal paraffin concentrationVSAvoidolefin tolerance of adsorption process

Core Design Contradiction:

Quantity of substanceVSAdaptability or versatility

Solution Approach 1:

The patent applies preliminary action by removing olefins from the recycle stream before it enters the adsorption separation unit. The side-cut fractionation column pre-treats the feed stream by extracting olefins, ensuring the adsorption unit receives feed within its acceptable olefin concentration limits, thus preventing adsorption efficiency degradation.

Inventive Principle:

Principle #10Preliminary action

3Productivity

If the feed stream contains non-normal paraffins and aromatics, then steam cracking yield decreases, but these components are difficult to separate and convert efficiently

Engineering Contradiction:

Improvesteam cracking yieldVSAvoidseparation and conversion process complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the feed stream into different components through adsorption separation, isolating normal paraffins from non-normal paraffins and aromatics. This segmented approach allows selective processing of normal paraffins through isomerization and recycling, while managing unwanted components separately, thereby improving steam cracking yield without requiring complete separation of all components.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies parameter changes by modifying the composition parameters of the feed stream to the steam cracking unit. Through adsorption separation and selective isomerization, the normal paraffin content parameter is increased while controlling olefin and aromatic content, optimizing the feed composition for maximum ethylene and propylene yield in the steam cracking process.

Inventive Principle:

Principle #35Parameter changes

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 process significantly increases the concentration of normal paraffins, improving the quality of the feedstock and enhancing the yield of ethylene and propylene, thereby increasing the profitability of steam cracking operations.

Implementation Method 1

separating a naphtha feed stream into a normal paraffin stream and a non-normal paraffin stream

Methodology Applied

Scientific EffectAdsorption: Adsorption

Implementation Method 2

isomerizing an isomerization feed stream taken from the non-normal paraffin stream over an isomerization catalyst to convert non-normal paraffins to normal paraffins

Methodology Applied

Scientific EffectCatalysis: Catalysis

Implementation Method 3

removing olefins from an isomerization effluent stream... passing the isomerization effluent stream through a bed of saturation catalyst

Methodology Applied

Scientific EffectCatalysis: Catalysis

Data Source

PatentUS11597883B2Process for removing olefins from normal paraffins in an isomerization effluent stream

Publication Date: 2023.03.07 UOP LLC

AI summary

Favorable isomerization conditions for producing normal paraffins can produce olefins. The process for separating normal paraffins from non-normal paraffins by adsorption has a limit on olefin concentration, so the olefins must be removed. We propose to remove olefins from the isomerization effluent stream that is recycled to the adsorption separation process.