Why WFE/SPD? Part 5 of 5 Flowable and Lubricating

Reason five to consider wiped film distillation: Flowable and Lubricating

The question arises: How do you know when wiped film distillation is the better option?

Wiped film distillation has many advantages as discussed in this series.  It also has a number of limitations.  Part 4 discussed the fact that wiped films stills are simple distillation apparatuses.  This post discusses the requirement of a flowable and lubricating feed material.

Wiped film still depends on the ability of the feed material to flow down the walls of the still.  Therefore, the feed material must be a liquid, or it must be handled under conditions that make it a liquid.  In addition, it must be a relatively thin liquid. 

Wiped film distillation becomes challenging when the feed materials rise to a viscosity of 10,000 cP and becomes impossible once the viscosity is greater than 100,000 cP. 

The material simply won’t flow down the walls of the still at these high viscosities and other technologies must be considered.

It is also important for the material to be lubricating. 

For instance, if your feed material is a product in water, this could pose a problem.  Water is not a very lubricating fluid.  Running a water solution in the still can cause wearing of the wiper blades and result in solid contamination entering your product stream.  If your desired product is the distillate, this is less of a concern. 

But in cases where the product is the residue, a non-lubricating fluid can cause problems.

For these reasons, the best feed materials for wiped film distillation are flowable, lubricating fluids.  If this describes your feed material, this is a technology to consider.

Should you wish to discuss a specific application, please message me, and we will set up a free call.