Oscillating Flow Minireactor for Solid Suspension Stability

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Solution Overview

Problem

Minireactors face challenges in preventing sedimentation and clogging due to their small cross-sectional areas, which limits their ability to achieve turbulent flow and increases manufacturing costs, while scaling up these reactors is complex and costly.

Innovation Solution

An oscillating flow minireactor with a reactor channel featuring directional changes and a smooth, unbaffled design, where the hydraulic diameter and curvature of the channel induce secondary flows, enhancing mixing without the need for internal structures, thus preventing sedimentation and clogging.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If conventional tube reactors use turbulent flow to prevent sedimentation, then mixing performance is improved, but the required tube length becomes impractically long

Engineering Contradiction:
Improvesuspension stabilityVSAvoidreactor length
Core Design Contradiction:
Stability of the object's compositionVSLength of stationary object

Solution Approach 1:

The patent applies oscillatory flow by periodically reversing the flow direction through the reactor. This periodic action creates intense mixing during each oscillation cycle, achieving suspension stability without requiring the long tube length needed for continuous turbulent flow. The oscillatory motion disrupts sedimentation patterns and keeps solids suspended throughout the reaction period.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The reactor system transitions from static or steady-state flow to dynamic oscillatory flow. By making the flow regime dynamic with periodic reversals, the system achieves enhanced mixing and suspension stability in a compact configuration, avoiding the need for impractically long reactors required by conventional steady turbulent flow approaches.

Inventive Principle:
Principle #15Dynamics

2Loss of energy

If minireactors operate at low linear velocity to reduce pressure drop, then energy consumption is reduced, but mixing performance deteriorates

Engineering Contradiction:
Improvepressure dropVSAvoidmixing performance
Core Design Contradiction:
Loss of energyVSStability of the object's composition

Solution Approach 1:

The oscillatory flow creates periodic acceleration and deceleration phases that generate intense mixing even at low average linear velocities. During each oscillation cycle, the rapid changes in flow direction and velocity create turbulence and eddies that enhance mixing performance without requiring high steady-state velocities that would cause excessive pressure drop.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system changes the flow parameters from steady-state high velocity to oscillatory low velocity with high acceleration phases. By modifying the temporal characteristics of the flow (adding periodic variation), the system achieves effective mixing at lower energy consumption levels, decoupling mixing intensity from average linear velocity and pressure drop.

Inventive Principle:
Principle #35Parameter changes

3Stability of the object's composition

If internal structures like baffles are added to enhance mixing, then mixing performance is improved, but device complexity and manufacturing costs increase

Engineering Contradiction:
Improvemixing performanceVSAvoidreactor structure
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent removes internal mixing structures like baffles and helical elements from the reactor design. Instead of using complex internal geometries to achieve mixing, the system extracts the mixing function and achieves it through external oscillatory flow actuation, resulting in a simpler reactor structure with fewer manufacturing requirements and lower costs.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The system replaces mechanical mixing structures (baffles, helical ribbons, static mixers) with an oscillatory flow mechanism. This substitution eliminates the need for complex internal mechanical or geometric features, achieving mixing through controlled fluid motion generated by oscillatory pumping or boundary conditions, thereby simplifying the overall device design.

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

4Object-generated harmful factors

If ultrasound is applied to prevent fouling, then solid deposition is reduced, but the reactor itself is put into motion causing connection damage and high energy consumption

Engineering Contradiction:
Improvesolid depositionVSAvoidenergy consumption
Core Design Contradiction:
Object-generated harmful factorsVSLoss of energy

Solution Approach 1:

The patent introduces an intermediary oscillatory flow mechanism that indirectly prevents solid deposition without directly moving or vibrating the reactor structure. The oscillatory flow acts as an intermediary that creates mixing and prevents fouling through fluid motion, while the reactor itself remains stationary, avoiding connection damage and reducing energy consumption compared to direct ultrasonic or mechanical vibration of the reactor.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 design effectively maintains solid materials in suspension, prevents reactor blockage, and allows for easier scale-up with lower manufacturing costs by achieving intense and uniform mixing within the minireactor, improving heat and mass transfer capabilities.

Implementation Method 1

an oscillating flow device; wherein the microreactor channel pathway comprises one or more directional changes, wherein the net flow of the reaction stream is in the forward direction but the oscillating flow device slows, pauses and/or reverses this forward flow periodically

Methodology Applied
Scientific EffectOscillatory flow:

Implementation Method 2

the hydraulic diameter and curvature of the channel induce secondary flows, enhancing mixing

Methodology Applied
Scientific EffectSecondary flow:

Implementation Method 3

each directional change has a ratio of hydraulic diameter, d h, to radius of curve, R c, of from 0.5 to 5

Methodology Applied
Scientific EffectCurvature-induced secondary flow:

Data Source

PatentEP2663396B1Oscillating flow minireactor for processing solid suspensions
Publication Date: 2021.12.15 PATHEON AUSTRIA GMBH & CO KG
  • EP2663396B1 patent drawingFigure 1~4
  • EP2663396B1 patent drawingFigure 5~6
  • EP2663396B1 patent drawing

AI summary

The present invention relates to an apparatus comprising a) an unbaffled reactor or microreactor having a channel defined by a pathway, and b) an oscillating flow device, wherein the channel pathway comprises a pluraltiy of directional changes. The reactor channel has a hydrolic diameter from 0.1 mm to 10 mm. A method of making said apparatus and the use of said apparatus to carry out a process on a suspension is also disclosed.