Reactor with Titanium Silicalite Recycling via Solid Silicon

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Solution Overview

Problem

The existing technologies face challenges in achieving continuous and efficient separation and recycling of the active catalyst in chemical reactions involving titanium silicalite, as the nanoscale TiO2 particles formed during ammoximation reactions clog filtration membranes, leading to irreversible blockages and catalyst depletion, and the addition of liquid silicon sources can cause sudden precipitation and blockages.

Innovation Solution

Incorporating a solid silicon sacrificial system, such as precipitated silicic acid, to control the dissolution of titanium silicalite, preventing the formation of inert TiO2 particles and extending filter service life by maintaining a self-regulated silicon dosage, allowing for continuous separation and recycling of the catalyst through a water discharge and return line system with a membrane filter.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If nanoscale TiO2 particles are formed during ammoximation reactions, then catalyst activity is maintained, but filtration membranes become clogged and blockages occur

Engineering Contradiction:
Improvecatalyst activityVSAvoidmembrane clogging
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

Silica particles are introduced as an intermediary substance that preferentially interacts with the filtration membrane surface. These silica particles act as sacrificial agents that bind to the membrane first, preventing the harmful TiO2 particles from causing irreversible clogging. The silica serves as a mediator between the catalyst particles and the membrane, controlling their interaction to maintain filtration functionality.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention uses inexpensive silica particles as disposable sacrificial material. These silica particles are intentionally consumed or depleted over time as they protect the membrane from TiO2 clogging. By using cheap, readily available silica instead of expensive membrane materials or complex anti-fouling coatings, the system achieves cost-effective long-term operation with extended filter service life.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Stability of the object's composition

If liquid silicon source is added to prevent catalyst dissolution, then catalyst stability is improved, but sudden precipitation and blockages occur

Engineering Contradiction:
Improvecatalyst stabilityVSAvoidsudden precipitation
Core Design Contradiction:
Stability of the object's compositionVSObject-generated harmful factors

Solution Approach 1:

The invention changes the physical state parameter of the silicon source from liquid to solid form. Solid silica particles dissolve or disperse gradually and controllably, avoiding the sudden supersaturation and rapid precipitation that occurs with liquid silicon sources. This parameter change transforms the release kinetics of silicon, maintaining catalyst stability while preventing harmful sudden blockages in the filtration system.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

Silica particles are introduced in advance as a preventive measure to control silicon availability in the reaction system. By having solid silica particles present from the beginning, the system maintains a controlled reservoir of silicon that prevents catalyst dissolution without causing sudden precipitation events. The preliminary presence of solid silica regulates the silicon concentration gradient and prevents supersaturation.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If cross-flow filtration is used to separate catalyst, then continuous recycling is achieved, but filter service life is reduced due to blockages

Engineering Contradiction:
Improvecontinuous recyclingVSAvoidfilter service life
Core Design Contradiction:
ProductivityVSDuration of action of stationary object

Solution Approach 1:

The invention converts the potentially harmful effect of particle accumulation on the membrane into a beneficial protective layer. By introducing silica particles that preferentially deposit on the membrane surface, the system creates a protective silica layer that actually enhances filtration performance and prevents more harmful TiO2 particle clogging. What could be seen as harmful (particle deposition) is transformed into a beneficial protective mechanism that extends filter service life while maintaining continuous recycling capability.

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

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 approach enables effective catalyst recycling and maintains a stable permeate flow, preventing membrane clogging and ensuring long filter service life, allowing for continuous operation in chemical reactions like ammoximation, while reducing equipment complexity and costs.

Implementation Method 1

a membrane filter which separates components dissolved and/or dispersed in the water from the water

Methodology Applied
Scientific EffectFiltration: Filter (physical)

Implementation Method 2

dosing a solid silicon sacrificial system (3 Si) is possible effectively to stop the dissolution process of the catalyst at the level of the nanoscale catalyst particles

Methodology Applied
Scientific EffectDissolution control: Solvation

Data Source

PatentEP2321263B1Reactor with titanium silicate recycling
Publication Date: 2017.06.07 EVONIK OPERATIONS GMBH
  • EP2321263B1 patent drawingFigure 1
  • EP2321263B1 patent drawingFigure 2
  • EP2321263B1 patent drawingFigure 3

AI summary

The invention relates to a system for carrying out chemical reactions, comprising a reactor (1), the reaction chamber of which contains hydrogen peroxide (H2O2) and titanium silicalite (TS-1) (Figure 3). The object of the invention is to improve upon such a system so that a continuous separation and recycling of the active catalyst to the reaction chamber is possible together with a long filter life. This object is achieved in that the reaction chamber contains a solid silicon source, the system comprises a water drain line (3) for draining water and components dissolved and/or dispersed therein out of the reaction chamber, that the water drain line (3) leads to a filter (4) that separates the components dissolved and/or dispersed in the water, and that the system comprises a recycle line (5) for returning components separated by way of the filter (4) back to the reaction chamber.