Pulsed Flow Reactor Scalability and Mixing

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Solution Overview

Problem

Existing flow reactors face challenges in scalability, process control, and production capacity due to limitations in design, particularly in laboratory settings, where increasing reactor size affects mass transfer, heat exchange, and flow hydrodynamics, leading to issues with pressure drop and residence time distribution.

Innovation Solution

A flow reactor with a substantially straight planar process channel and a pulsatile flow generator that creates a unidirectional net flow with an oscillatory flow superposed, allowing for turbulence generation at low net flow rates without the need for extensive static mixing elements, enabling increased reactor volume and throughput while maintaining process control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the tube diameter or channel cross-section is increased to increase internal volume, then production capacity is improved, but mass transfer and heat exchange control deteriorate

Engineering Contradiction:

Improveproduction capacityVSAvoidprocess control

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The reactor channel is divided into multiple segments with static mixing elements that create local splitting and recombination of fluid flow. This segmentation allows the reactor to achieve high production capacity through increased overall volume while maintaining effective mass transfer and heat exchange control in each segmented section, preventing the deterioration of process control that would occur in a single large-volume channel.

Inventive Principle:

Principle #1Segmentation

2Productivity

If the tube or channel length is increased to increase internal volume, then production capacity is improved, but pressure drop increases

Engineering Contradiction:

Improveproduction capacityVSAvoidpressure drop

Core Design Contradiction:

ProductivityVSStress or pressure

Solution Approach 1:

The reactor transitions from a simple linear channel to a serpentine (meander) pattern, utilizing two-dimensional space more effectively. This dimensional change allows the channel to achieve the necessary length for high production capacity while being arranged in a compact configuration that reduces the linear distance and associated pressure drop compared to a straight channel of equivalent volume.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Ease of operation

If high flow rates are used to create turbulent flow and avoid dead volume, then mixing is improved, but the reactor length must be increased leading to higher pressure drop

Engineering Contradiction:

Improvemixing efficiencyVSAvoidpressure drop

Core Design Contradiction:

Ease of operationVSStress or pressure

Solution Approach 1:

The static mixing elements create periodic splitting and recombination of fluid streams as flow progresses through the reactor. This periodic action generates localized turbulence and enhances mixing efficiency without requiring continuously high flow rates throughout the entire reactor length, thereby achieving effective mixing while limiting the overall pressure drop.

Inventive Principle:

Principle #19Periodic action

4Productivity

If serpentine reactors are placed in series to increase length and residence time, then production capacity is improved, but pressure drop becomes uncontrollable

Engineering Contradiction:

Improveproduction capacityVSAvoidpressure drop

Core Design Contradiction:

ProductivityVSStress or pressure

Solution Approach 1:

Multiple serpentine channels are merged into a single integrated reactor structure with shared inlet and outlet connections. This merging allows the reactor to achieve the equivalent length and residence time of series-connected reactors while maintaining a unified flow path that enables better pressure drop control compared to truly series-connected separate reactor units.

Inventive Principle:

Principle #5Merging (Combining)

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 enhances scalability, increases production capacity, and improves mixing and mass transfer, making it suitable for multiphasic reactions and photochemical processes without significant changes in pressure drop or residence time distribution.

Implementation Method 1

a flow generator configured to generate a pulsatile flow within said process channel, the pulsatile flow comprising a unidirectional net flow component through said process channel along said longitudinal direction and an oscillatory flow component superposed on said net flow component

Methodology Applied

Scientific EffectPulsatile flow:

Implementation Method 2

allowing for turbulence generation at low net flow rates

Methodology Applied

Scientific EffectTurbulence: Turbulence

Data Source

PatentUS11291971B2Pulsed flow reactor and use thereof

Publication Date: 2022.04.05 AJINOMOTO OMNICHEM SA

AI summary

A planar flow reactor includes a straight planar process channel, a flow generator, and a plurality of static mixing elements disposed within the process channel. The flow generator is configured to generate a pulsatile flow within the process channel, and the static mixing elements are configured to locally split and recombine the flow. The straight planar process channel enables the generation of a flow pattern that is largely independent of the width of the process channel, meaning that the throughput may be increased by increasing the width without significantly affecting the residence time distribution or the flow behavior. Furthermore, by creating a pulsatile flow within the process channel, turbulence and/or chaotic fluid flows may be generated even at low net flow rates, i.e. low net Reynolds numbers.