Mixing, Homogenization and Blend Time

In industrial process engineering, mixing is a unit operation that involves manipulation of a heterogeneous physical system to make it more homogeneous. By homogenization is understood the minimization of the concentration gradient of different compounds or temperature gradients in the entire system. This unit operation plays a critical role in many chemical processes: from food in grocery stores, healthcare and pharmaceutical products, to polymers, minerals, paint and coating, biofuels, and many others, most products require mixing as an essential production step.

A distinction is made in process engineering between the following basic mixing tasks:

  1. Homogenization: Reduction of concentration or temperature gradients within defined system
  2. Suspension: Whirling up and suspending solid particles
  3. Dispersion: liquid/liquid: emulsions, polymerization, etc.
  4. Dispersion liquid/gas : aeration, mass transfer
  5. Heat transfer : intensifying of the heat transmission (cooling, heating)

In order to reduce the investments and operating costs and maximizing the performance of stirred reactors, Computational Aided Engineering (CAE) offers proven tools, such as advanced Computational Fluid Dynamic (CFD) and automatic optimization, to design optimal mixing solutions. There is no longer need to take the conventional route of experimental trial and error, which is expensive and very time consuming. Nowadays it is possible to reliably simulate dozens (or hundreds) of design in very short time; modern optimization algorithms can analyze thousands of data and propose optimum designs, saving time, capital expenditure and operating costs.

With high performance CFD, it is possible to simulate a large number of problems and tasks operations and to analyze and evaluate critical process parameters:

 

Figure 1: Suspension of solid particles in stirred tank reactor (click on the picture to watch the video)

Figure 2: Analysis of mixing time in stirred tank reactor (click on the picture to watch the video)

Figure 3: Analysis of tracer distribution (click on the picture to watch the video)

Figure 4: Rushton turbine - Velocity field (normalized)

Figure 5: Rushton turbine – Turbulent dissipation rate (normalized)

Stirred tank design engineers have always been drive by the desire of reaching the highest mixing efficiency, THINK Fluid Dynamix has the tools, the people and the experience to help our clients to achieve their goals.