What Is Mixing?
As kids we all understand that the harder and more violently, we shake something the better it becomes mixed.
As engineers we want to understand what is the fundamental force that is causing this, and how can we optimize it “so we can get the most for the least.”
Mixing is the act of physically taking two different materials and dispersing them equally amongst each other.
Qualitative measure of this is, “ do I see uniformity in the blend”
Quantitatively is, have I produced enough force to break up the two substances in small enough “packets” i.e. ( droplets, material diameter, etc.) such that the smaller packets are able to disperse within the mixture
Process Mixing
Within industrial processes mixing two or more things together are critical in the operation. A few examples; large scale bakeries, gas treatment, measurement, and oil refineries to name a few.
Regardless of what is being mixed a means to put context into “what is good enough” so that achievement can be done safely and cost effectively to meet the desired outcome is always needed.
Mixing Using An Orifice Plate
- One of the first and simplest ways that process mixing was done between two liquids was placing an orifice plate in the line.
- The idea being that as you change the speed of the fluid increased eddies “ swirl and frothing” would occur just down stream.
- Fundamentally: I am converting potential energy stored as pressure into kinetic energy which is then imparted to the fluid causing the mixing downstream of the orifice.
Designing of a Mixing Column
- In 1928 it was common to design mixing columns which were a series of orifices to inject sulfuric acid into flowing oil to allow treatment of the oil.
- The material would be injected upstream of the flow and the bulk flow would be subjected to a series of plates to allow mixing.
Mixing Column Design
- In this example of mixing 300bbl/hr of crude oil with sulfuric acid years of experience showed that no more that 30-40psig of pressure drop was needed to properly mix.
- So, between 15-20 plates were needed.
Conclusion
- In today’s environment engineers have been given tools that can see more data, can monitor and model things that the old jedi engineers inherently understood through trial and error.
- Today we have fancy geometrically designed static mixers, and swirl tubes. We have developed new patterns with fractal diffusers, letting us improve on the concept of how best to impart the kinetic energy into the fluid.
- A.I. tools, such as the one offered by Mechademy coupled with decades of knowledge and experience will help bring your business from an inefficient orifice plate to a proverbial fractal diffuser.
