Propylene Separation via Adsorption and Guard Bed Protection

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Solution Overview

Problem

Conventional methods for separating propylene from dehydrogenation products of propane-containing feedstock require excessive energy and result in inefficient separation due to the deterioration of adsorbing agents, necessitating a more efficient process that reduces equipment investment and operation costs.

Innovation Solution

A method involving a depropanizer to separate C4+ hydrocarbons, followed by an adsorption separation unit with a guard bed and selective adsorption-desorption using a desorbing agent to maintain separation efficiency and reduce adsorbing agent deterioration, allowing for the separation of propylene without low-temperature cooling and a C3 product splitter.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional low-temperature separation process and C3 product splitter are used, then propylene can be separated from dehydrogenation products, but excessive energy is consumed and adsorbing agents deteriorate

Engineering Contradiction:

Improveseparation efficiencyVSAvoidenergy consumption

Core Design Contradiction:

Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The depropanizer is positioned upstream of the adsorption separation unit to remove C4+ hydrocarbons before they can deteriorate the adsorbing agent. This preliminary action prevents the harmful interaction between C4+ components and the adsorbing agent, maintaining separation efficiency while avoiding the need for excessive energy consumption in subsequent separation stages

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The separation process is divided into distinct stages: first, the depropanizer separates C4+ hydrocarbons from the feed stream; second, the adsorption separation unit separates propylene from propane using adsorbing agents. This segmentation protects the adsorbing agents from exposure to C4+ components, preventing deterioration and reducing energy consumption

Inventive Principle:

Principle #1Segmentation

2Device complexity

If adsorption separation unit is used without depropanizer, then equipment investment is reduced, but adsorbing agents deteriorate and separation efficiency decreases

Engineering Contradiction:

Improveequipment investmentVSAvoidseparation efficiency

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The depropanizer is installed upstream to perform preliminary removal of C4+ hydrocarbons before the feed enters the adsorption separation unit. This preliminary action prevents the C4+ components from reaching and deteriorating the adsorbing agents, thereby maintaining high separation efficiency over time

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The depropanizer acts as an intermediary device between the feed stream and the adsorption separation unit. It removes harmful C4+ components that would otherwise directly contact and deteriorate the adsorbing agents, protecting the separation efficiency without requiring complex additional equipment downstream

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If depropanizer is added upstream, then adsorbing agent deterioration is prevented, but equipment investment increases

Engineering Contradiction:

Improveseparation efficiencyVSAvoidequipment investment

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The depropanizer extracts and removes C4+ hydrocarbons from the feed stream before it enters the adsorption separation unit. By taking out the harmful components that cause adsorbing agent deterioration, the system maintains reliable separation efficiency. The extracted C4+ stream can be processed separately or utilized in other applications

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Rather than using expensive, highly durable adsorbing agents that can handle C4+ components, the invention uses a simpler, more economical depropanizer upstream to remove C4+ hydrocarbons. This approach trades a relatively simple separation device for the protection of more critical separation components, reducing overall equipment investment while maintaining reliability

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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 effectively separates propylene and propane using fewer distillation trays, reducing energy consumption and maintaining high separation efficiency over time, thereby lowering equipment costs and improving processing efficiency.

Implementation Method 1

transferred into a depropanizer 108 so that at least a portion of a C4+ hydrocarbon is separated as a bottom stream

Methodology Applied

Scientific EffectDistillation: Distillation

Implementation Method 2

split into a propane-rich stream and a propylene-rich stream through which olefin is selectively adsorbed on an adsorbing agent

Methodology Applied

Scientific EffectAdsorption: Adsorption

Implementation Method 3

displacement desorption is performed using a desorbing agent

Methodology Applied

Scientific EffectDesorption: Desorption

Data Source

PatentUS10221111B2Method for separating propylene from dehydrogenation reaction products of propane-containing feedstock

Publication Date: 2019.03.05 GAS CO

AI summary

An embodiment of this invention provides a method of effectively producing propylene by separating reaction products obtained by dehydrogenating propane-containing feedstock, using an adsorption process in lieu of conventional low-temperature separation processes.