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