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Liquid-liquid coalescers

Liquid-liquid coalescers

Liquid-liquid coalescers

We are small producers of biodiesel and we want to increase our production capacity to 20000 tons per year. One of the problems is slow separation of methylester and glycerin phase. We have horizontal gravity separators .Does anybody know what kind of coalescing mediums are being used for the better separation of methyl ester and glycerine ? Which companies produce this coalescers?Do you have any additional suggestions for the better separation?
Thank you,

RE: Liquid-liquid coalescers


try PALL,


RE: Liquid-liquid coalescers

Try 3L Filters in Cambridge, Ontario Canada.  Sounds like a good application for a coalescing filter.

RE: Liquid-liquid coalescers

Have you tried cooling? This will enhance the separation of some mixtures.


RE: Liquid-liquid coalescers

Some recommend centrifuging followed by a water wash.

RE: Liquid-liquid coalescers

Koch-Otto-York and Knitmesh are two manufacturers who can make this kind of equipment.
Cooling (or heating) can help, depending on the physical properties of the two components.  I've seen it work both ways.  Depends how much capacity increase you need.

RE: Liquid-liquid coalescers

We used several very large horizontal separators where we added Coalescing Baffles to increase production and seperation.  

To further increase production we went to Centrifugal Contactors, at the time Podbielniaks.  Not only did the machines permit the production increase desired they greatly increased the purity of the desired component eliminating an additional washing step.


RE: Liquid-liquid coalescers

I am biased I am afraid as an employee of Pall Corporation in the UK. I am sure my colleagues in the USA (based in Cortland NY state)would be happy to receive an enquiry from you. I have copied the link to them and hopefully since the company name has already been suggested by another contributor my action will not be contrived as "selling".
We are more experienced in Liquid/Liquid coalescer design here in Europe, so out of interest I will also pass your query on here just in case we have some relevant experience - sorry it is not my area so I cannot give you any immediate help.

Good Luck,


RE: Liquid-liquid coalescers

i recently spoke to PALL regarding seperating oil from water (down to levels of 1ppm).

They seem very experienced in phase separation etc using there Liquid/liquid coalsescers.

RE: Liquid-liquid coalescers


Don't get me wrong my PAll colleagues in the USA are more than capable of looking at any L/L or L/G coalescer. In Europe we have done slightly more in the way of more difficult separations, which has been led by the greater environmental drive in Europe.

Orion may be interested to know that we have already tested and sold coalescers in respect of his application.


RE: Liquid-liquid coalescers

To increase the throughput on your vessel you need to increase the settling rates and improve coalescing.

Settling rates are a function of droplet size, the gravity difference between the fluids being separated and the viscosity of the continuous phase.  

To create optimum separation conditions you need to do the following: -

- Maximise droplet sizes in the vessel by minimising shear upstream of the vessel (No unnecessary pressure drops!) and by installing media in the vessel that encourages droplet growth (coalescing media).
- Creating optimum settling rates by adjusting the feed temperature.  The optimum feed temperature can be determined by calculating the settling velocity using Stokes law, over a range of feed temperatures.  If the feed temperature is to be increased remember you may have to increase cooling capacity downstream of the vessel.

The cost of providing additional heat input upstream of the vessel (larger heat exchangers and fuel\utility costs) together with the costs of installing new coalescing media within the vessels should be compared to simply installing larger vessels to increase residence time.  

If you are not used to carrying out these evaluations yourself it might be worth enlisting the services of a design house or consultant who will be helpful in formulating an overall execution plan for carrying out the upgrade.


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