Vinyl Aromatic Distillation Column Passivation

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Solution Overview

Problem

Distillation units for vinyl aromatic compounds, such as styrene, face fouling issues due to polymerization, leading to decreased efficiency and the need for frequent maintenance to remove polymer seeds.

Innovation Solution

A cleaning process involving mechanical cleaning followed by passivation, where a flux comprising a passivation mixture is passed through the distillation columns at elevated temperatures and pressures, using polymerization inhibitors and steam or hydrocarbons devoid of vinyl groups.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If mechanical cleaning is performed to remove polymer seeds, then fouling is reduced, but polymer seeds remain as living chain residues that reactivate fouling

Engineering Contradiction:

Improvedistillation efficiencyVSAvoidpolymer seeds

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The cleaning process is followed by a passivation step that performs preliminary deactivation of polymer seeds before the distillation unit is restarted. This preliminary action ensures that harmful polymer seeds are neutralized in advance, preventing reactivation and fouling during subsequent operation.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The passivation mixture converts the harmful polymer seeds into inactive forms through chemical reaction. The polymerization inhibitors in the passivation mixture react with the living chain polymer residues, transforming them from harmful active seeds into benign inactive compounds, thereby eliminating the fouling problem.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Reliability

If polymerization inhibitors are used during distillation to prevent polymerization, then polymerization is inhibited, but costs increase

Engineering Contradiction:

Improvepolymerization preventionVSAvoidpolymer inhibitor cost

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

Instead of continuously adding polymerization inhibitors during distillation, the process performs a preliminary passivation step during cleaning that deactivates polymer seeds. This preliminary action eliminates the need for continuous inhibitor addition, reducing costs while maintaining polymerization prevention.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The passivation step enables the distillation unit to self-protect against polymerization by deactivating polymer seeds during cleaning. This self-service mechanism eliminates the need for continuous external intervention with polymerization inhibitors, reducing operational costs.

Inventive Principle:

Principle #25Self-service

3Ease of manufacture

If high-pressure cleaning is used to remove dirt from heat exchangers, then cleaning effectiveness is improved, but jet water cannot reach every nook and cranny

Engineering Contradiction:

Improvecleaning effectivenessVSAvoiddirt in nooks and crannies

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent replaces mechanical high-pressure jet cleaning with a thermal-chemical passivation process. The passivation mixture, heated to elevated temperatures, chemically deactivates polymer seeds and penetrates into nooks and crannies where mechanical jets cannot reach, achieving complete cleaning effectiveness.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The passivation process changes the temperature parameter by heating the cleaning medium to elevated temperatures (typically 50-100°C). This temperature increase enhances the penetration ability of the cleaning solution into difficult-to-reach areas and accelerates the chemical deactivation of polymer seeds, overcoming the limitations of mechanical high-pressure cleaning.

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

The process effectively deactivates polymer seeds, reducing the need for polymer inhibitors during distillation, and restores the original efficiency of the distillation unit.

Implementation Method 1

a flux comprising a passivation mixture is passed through at least one distillation column under passivation conditions comprising a temperature of at least 90° C.

Methodology Applied

Scientific EffectThermal heating: Heating

Implementation Method 2

a flux comprising a passivation mixture is passed through at least one distillation column

Methodology Applied

Scientific EffectDiffusion: Diffusion

Data Source

PatentUS12319650B2Cleaning process of a vinyl aromatic compounds distillation unit and processes including such cleaning process

Publication Date: 2025.06.03 TOTALENERGIES ONETECH

AI summary

The disclosure relates to a cleaning process of a vinyl aromatic compounds distillation unit wherein the vinyl aromatic compounds distillation unit comprises one or more distillation columns, the process comprises a step of cleaning one or more distillation columns followed by a step of passivation of at least one distillation column wherein a flux comprising a passivation mixture is passed through at least one distillation column under passivation conditions comprising a temperature of at least 90° C., wherein the passivation mixture comprises a component A being one or more polymerisation inhibitors; and a component B selected from steam and/or one or more hydrocarbons devoid of vinyl group. The disclosure also relates to the process of purification and of production of one or more vinyl aromatic compounds that include the said cleaning process.