Hi all,
I'm in charge of a continuous filter unit that uses two liquid ring vacuum pumps (3000m3/h @ -200mbarg) to produce the vacuum underneath the cloth.
The unit is operated under a nitrogen blanket with a continuous nitrogen purge (60m3/h) and a fan & control valve for venting.
We currently use water as the seal liquor but the higher humidity this causes in the unit means water is being entrained in the liquor being filtered which is bad for solvent recovery/recycle in a later stage.
My question is, can anyone recommend a liquid that can meet the following requirements:
- High boiling point (to minimize the quantity of seal liquor removed/lost);
- compatible with Viton is a must, as both the pumps and a recirculation pump used for cooling the sealing liquor through a heat exchanger have Viton seals.
- Low viscosity is a must to ensure an adequate flow around the pumps is maintain at there relatively low operating vacuums. An oil was tried in the past but water contamination caused it to emulsify and go thick.
- Ideally low toxicity but this isn't a must
- A flash point more than 80 oC is desirable
- high heat capacity would be desirable to minimize the temperature rise across the pump.
Any suggestions/comments/recommendations are welcome.