Brush Cleaning for Tube Bundle Reactor Catalyst Recharge

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Solution Overview

Problem

Current methods for recharging tube bundle reactors with new catalyst beds are costly and inefficient, as they require abrasive sandblasting or corrosive liquid washing, which can damage the catalyst and lead to uneven deposition of carbon and rust, affecting the reactor's performance and selectivity in heterogeneously catalyzed partial gas phase oxidations.

Innovation Solution

A process where, after removing the spent catalyst bed, a solid deposit of molybdenum oxide or molybdenum oxide hydrate is brushed away from the reactor tubes' inner walls using a brush before recharging with a new catalyst bed, utilizing the protective properties of these deposits to prevent rust and carbon formation, thus avoiding abrasive methods and maintaining catalyst activity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If abrasive sandblasting or corrosive liquid washing is used to clean reactor tubes, then deposits are removed, but the reactor walls and catalyst are damaged

Engineering Contradiction:
Improvecleaning effectivenessVSAvoiddamage to reactor walls and catalyst
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces abrasive mechanical cleaning (sandblasting) and corrosive chemical cleaning with a mechanical brush cleaning system that uses controlled friction. The brush mechanically removes deposits through friction without the damaging effects of abrasives or corrosives, solving the contradiction between cleaning effectiveness and protection of reactor components.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the parameters of the cleaning process by controlling brush pressure, rotation speed, and contact force to achieve effective deposit removal while maintaining safe stress levels on the reactor walls and catalyst. This parameter control allows cleaning effectiveness without component damage.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If abrasive cleaning methods are used, then deposits are removed, but catalyst activity is reduced and deposition becomes uneven

Engineering Contradiction:
Improvedeposit removalVSAvoidcatalyst performance and selectivity
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent substitutes harsh abrasive mechanical cleaning with a controlled brush cleaning system that applies gentle, uniform friction. This removes deposits effectively while preserving catalyst integrity and activity, preventing the reliability issues caused by abrasive damage and uneven catalyst deposition.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent controls cleaning parameters (brush pressure, contact time, rotation speed) to achieve uniform deposit removal without damaging the catalyst. This parameter optimization ensures both effective cleaning and preservation of catalyst performance and selectivity.

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 method effectively removes deposits without damaging the reactor walls, maintains catalyst performance, and reduces the need for abrasive cleaning, ensuring consistent reactor operation and product selectivity over extended periods.

Implementation Method 1

a solid deposit (solid film) which comprises molybdenum oxide and/or molybdenum oxide hydrate and has been deposited on their inner wall is brushed away at least partly with the aid of a brush

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

brushed away at least partly with the aid of a brush

Methodology Applied
Scientific EffectAbrasion: Abrasion

Implementation Method 3

a heterogeneously catalyzed partial preceding gas phase oxidation of an organic compound has been performed in a fixed catalyst bed which was disposed in these reaction tubes and comprised at least shaped catalyst bodies whose active composition is a multielement oxide comprising the element Mo in the oxidized state

Methodology Applied
Scientific EffectHeterogeneous catalysis: Catalysis

Implementation Method 4

partial gas phase oxidation of an organic compound

Methodology Applied
Scientific EffectOxidation: Oxidation

Data Source

PatentUS9126171B2Process for recharging the reaction tubes of a tube bundle reactor with a new fixed catalyst bed
Publication Date: 2015.09.08 BASF SE

AI summary

A process for recharging the reaction tubes of a tube bundle reactor with a new fixed catalyst bed, in which a heterogeneously catalyzed partial gas phase oxidation of an organic compound had been performed beforehand in a preceding fixed catalyst bed comprising Mo-comprising multielement oxide active compositions to form a steam-comprising product gas mixture, in which, before the recharge, solid deposit which had been deposited on the tube inner walls and comprises molybdenum oxide and/or molybdenum oxide hydrate is brushed away with the aid of a brush.