Hydrodearylation of C9+ Aromatic Bottoms for BTEX Recovery

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Solution Overview

Problem

Refineries face challenges in economically utilizing aromatic complex bottoms, which deteriorate gasoline quality and are not suitable for blending due to high sulfur, aromatics, and benzene levels, leading to engine performance issues and process reject material.

Innovation Solution

A method involving hydrodearylation of C9+ aromatic complex bottoms using a catalyst and hydrogen under specified conditions to produce BTEX-rich and solvent fractions, with the solvent fraction being further processed into fuel oil blending components and the BTEX-rich fraction used for gasoline blending.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If aromatic complex bottoms are added to the gasoline fraction, then the utilization of bottoms is improved, but the gasoline quality deteriorates and engine performance is negatively impacted

Engineering Contradiction:

Improveutilization of aromatic complex bottomsVSAvoidgasoline quality and engine performance

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent applies parameter changes by subjecting aromatic complex bottoms to hydrodealkylation reaction conditions (temperature, pressure, catalyst, hydrogen) to transform the chemical composition. This converts high-boiling aromatic compounds into lower-boiling BTEX components that meet gasoline quality specifications, thereby improving both utilization and quality simultaneously

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent extracts and removes the problematic high-boiling aromatic compounds from the bottoms stream through hydrodealkylation, separating them into usable BTEX fractions for gasoline blending and rejecting only the residual heavy components, thus eliminating the quality deterioration issue while maintaining high utilization

Inventive Principle:

Principle #2Taking out (Extraction)

2Object-affected harmful factors

If aromatic complex bottoms are rejected as process reject material, then the gasoline quality is maintained, but the economic value of the bottoms is lost

Engineering Contradiction:

Improvegasoline qualityVSAvoideconomic value of aromatic complex bottoms

Core Design Contradiction:

Object-affected harmful factorsVSLoss of substance

Solution Approach 1:

The patent converts the harmful high-boiling aromatic bottoms into beneficial BTEX components through hydrodealkylation. The reaction transforms what was previously waste material into valuable gasoline blending components, simultaneously maintaining quality standards and recovering economic value

Inventive Principle:

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

Solution Approach 2:

By changing the chemical parameters of the bottoms through catalytic hydrodealkylation (using hydrogen, catalyst, and specific reaction conditions), the patent transforms the composition from unsuitable heavy aromatics into valuable BTEX, turning a loss into a gain

Inventive Principle:

Principle #35Parameter changes

3Productivity

If toluene is converted through disproportionation or hydrodealkylation, then higher value products are produced, but benzene is formed which creates environmental compliance issues

Engineering Contradiction:

Improveproduction of higher value productsVSAvoidbenzene formation

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent applies local quality by using a zeolite catalyst with specific pore structure and acidity that selectively promotes hydrodealkylation reactions while suppressing disproportionation reactions. This localized catalytic action at the molecular level directs the reaction pathway to produce desired products while minimizing unwanted benzene formation

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the reaction parameters including using hydrogen atmosphere, specific temperature ranges, and zeolite catalyst to favor hydrodealkylation over disproportionation. These parameter changes shift the reaction selectivity to produce ethylbenzene and xylene while suppressing benzene formation, thus maintaining productivity while reducing harmful emissions

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 method effectively converts aromatic complex bottoms into valuable BTEX and solvent fractions, meeting regulatory standards for benzene content and improving gasoline quality while utilizing the waste as fuel oil blending components.

Implementation Method 1

reacting a feedstream comprising all or a portion of the C9+ aromatic bottoms in the presence of a hydrodearylation catalyst and hydrogen under specified reaction conditions for hydrodearylation to produce at least liquid effluents containing dearylated hydrocarbons

Methodology Applied

Scientific EffectHydrodearylation: Chemical Bonding

Data Source

PatentUS20250388825A1Hydrodearylation of aromatic bottoms to produce BTEX and aromatic solvent

Publication Date: 2025.12.25 SAUDI ARABIAN OIL CO

AI summary

A process for treatment of C9+ aromatic complex bottoms feedstream that includes reacting the feedstream in the presence of a hydrodearylation catalyst and hydrogen under specified reaction conditions for hydrodearylation to produce liquid effluents containing dearylated hydrocarbons and separating the liquid effluents into a BTEX-rich fraction and a solvent fraction, and recovering the solvent fraction.