UF Permeate Flow Control

[handling2]

Before I ask my questions to you, this is the application:

Filter: 1 ceramic module, total membrane surface of 9 m2.
Pumps: 1 feed pump, 2 bar; 1 recirculation pump 2 bar which creates a cross flow velocity of 5 m/s along membrane surface
Purpose: concentrate oily wastewater in a tank to discharge a minimal volume of wastewater (recirculation)

Questions:
is there a way to predict flux in fonction of tmp, cross flow velocity and feed viscosity ?
I am planning to regulate permeate flow by a control valve which regulates permeate flow (with a flow transmitter + controller) in order to reach permeate SETPOINT, using minimal TMP.

Is there beside this regulation another method to control permeate flow? I was thinking about varying pump speed?

Best Regards

 

[FiltrationEngineer]

I would control the system the way you have it described. If you vary internal pressure via pump speed you will lose the scouring effect you get from maximum velocity against the membrane.

Using a control valve and a permeate flow meter will work best.
The best way to figure out what flux rates you can achieve is to run a pilot test. With a pilot, you can find out what maximum concentration you can achieve on the feed side and What kind of flux rates and fouling you can expect in the full scale system. Also, you really don't know all the chemicals in the wastewater and lots of stuff in cleaning compounds are bad for ceramic membranes (silicates, wax, etc.) A pilot will identify those problems.