Inline Mixing
Key Benefits Include:
- determine optimal mixing lengths / settings
- determine residence times
- improvement of yield / quality by responding to process or material variations
Introduction
Inline mixing/blending is widely used in many industries, such as pulp and paper, food, petrochemical. There are two main inline mixing techniques:
- static mixers
- driven mixers
These offer different trade-offs in terms of process efficiency, energy efficiency and relative pressure drop across the mixer.
In the case of static mixers, the critical factor is the number of elements / overall length of the mixer. Although other factors can include injection point, flow rate and changing physical properties of ingredients.
As with batch mixing, the same issues of identifying mixing end-points is a critical factor.
Process tomography provides a useful tool to quantifying mixing characteristics.
The mixing index σ is calculated as follows where:
|
C1i = conductivity of pixel i in tomogram 1 For example, |
 |
This technique can be used to:
- optimise set up conditions
- adjust mixing rates for changes to raw materials
Process tomography can also be used to continuously sample materials as they pass through a pipe. This can provide an on-line measurement of product quality to validate that materials have been mixed to the appropriate standard.
The instrumentation required for inline mixing is typically the two plane p2000. This unit is highly portable and can be taken from plant to plant for process optimisation.
In cases where organic materials are being mixed, the m3000 should be used.
In rapid mixing systems (such as jet mixing which are frequently used in the production of nano-particles), the z8000 can be used. The z8000 can measure at more than 1,000 frames per second, resolving rapidly changing flow features. This provides an opportunity to improve homogeneity of the reaction space and so improve the quality of the nano-particles produced.
Generally inline sensors are fitted for inline mixing processes.
