Mixing in microfluidic

structures

Dr. Ing. Daniel Jussen

B. Sc. David Lüthy

Dr. Ing. Peter Riedlberger

Microprocess engineering

and particulate systems

Advantages:

• Rapid mixing

• Defined temperature

control

• Continuous processing

• Ease of serial reactions

• Favorable for hazardous

processes

• Ease of Scale up

• Flexible processes

Challenges:

• Macro to micro interface

• Backpressure

• Fouling

• Overhead

Microfluidic mixing concepts

Kashid, M. N., Renken, A., & Kiwi-Minsker, L. (2015). Microstructured Devices for Cemical Processinf.

Campos Domínguez, C., & Gamse, T. (2016). Process intensification by the use of micro devices for liquid fractionation with supercritical carbon dioxide. Chemical Engineering

Research and Design, 108, 1–7. http://doi.org/10.1016/j.cherd.2016.01.011

Multilamelar mixer (Simm V2)

High collision mixer

Mixing efficiency – Test

reaction

4

Competitive parallel reaction

𝑋𝑠 =𝑌

𝑌𝑆𝑇𝑋𝑠= Segregation index 𝑌= Y is the ratio of acid mole number

consumed by reaction (2) to the total acid mole number

𝑌𝑆𝑇= Y in the total segregation case when the micromixing process is

infinitely slow

Villermaux-Dushman

Method

I3- detectable 353 nm

Villermaux-Dushman

Method

SIMM-V2 (multilamellar mixer)

R300 (SAR/caterpillar mixer)

R600 (SAR/caterpillar mixer)

Segregation index (XS) depence on the mixer type and flow rate (Q)

Precipitation of

Bariumsulfate

7

Model reaction: Ba2+ SO42- BaSO4

SIMM-V2 (multilamellar mixer)

Batch process

left: particle size distribution for diferent mixers and batch reaction,

right: dependence of the mean particle diameter for different mixers

Inte

nsity

/%

M4 (high collision mixer)

R600 (SAR/caterpillar mixer)

R300 (SAR/caterpillar mixer)

Particle Size d/ nm flow rate Q /mL min-1

Summary and Outlook

• Mixing has significant influence on reactions

• Choice of mixer influences reaction and

performance

• Utilization of microfluidic mixing setups for a

model process

– P/TiO2 process for exemplary process

intensification

– Fouling remidation studies for exemplary process

Villermaux-Dushman

Method

𝑋𝑠 =𝑌

𝑌𝑆𝑇𝑋𝑠 = Segregation index

𝑌 = Y is the ratio of acid mole number consumed by reaction (2) to the total acid mole number

𝑌𝑆𝑇 = Y in the total segregation case when the micromixing process is infinitely slow