Application: Mixing
Mixing/Blending:
- Solid-liquid, including crystallisation, switch from batch to continuous, control of in-line mixing
- Gas-liquid, including optimisation of high intensity gas mixing
- Liquid-liquid, including investigation of static mixers
Applications:
- Liquid-Liquid/Solid-Liquid/Gas-Liquid
- Lab/Pilot/Production
- Continuous/Batch/Semi-Batch
- Research/Process monitoring/Process Development
Benefits include:
- Development of new mixing techniques
- Determine mixing efficiency
- Monitor and improve product quality
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The experimental results shown are from a study for a chemical company who were designing a new manufacturing facility. Part of the manufacturing process involved an addition into stirred tank reactors.
How it is used
Process vessels can be retrofitted with a linear tomography probe - typically as a baffle - to measure axial mixing and solids concentration levels. By combining this with radial data from the probe, it can also be used as a mixing index.
Mixing index versus mixing speed
Heterogeneity index at different
impeller speeds
Mixing Research
At the research level, tomography provides conductivity information on over 300 unit volumes (voxels) in a single plane. This conductivity data can be correlated with component concentrations.
Each set of data is captured in less than 30 milliseconds, allowing the progression of many mixing processes to be viewed over time. By combining planes together - up to 8 with a single instrument - it is possible to interpolate between planes and render 3-D images of different stages in the mixing process.
The benefits from using this data include:
- testing CFD models with actual data throughout the vessel
- determining levels of homogeneity / heterogeneity within a process vessel or static mixer by looking at the differences between different unit volumes
- measuring residence times within reactors
- mapping flow paths within vessels and identifying recirculation loops and dead zones
- improved mixing homogeneity and efficiency
These mixing plots show the mean conductivity from measurement planes 2, 4, 6 and 8 from an eight-plane stirred tank following the addition of a high conductivity tracer next to the impeller (Figure 1) (which is located in measurement plane 8) and on the liquid surface (Figure 2).
Figure 1
Figure 2
