1 reply to this topic

[Asif Aziz]

Dear Group Members,

 

Hope everybody is enjoying his/her good health.

 

We are using root blowers (lobe type pump) as a vacuum booster in our polyester polyol plant (circuit is attached). We apply vacuum to reactor through liquid ring vacuum pump and when this pump achieves its maximum vacuum, root blowers are used to fine the vacuum. We are facing a problem in root blower that water get mixed with lubrication oil at both ends of  the blower (at one end it is for gears and on other it is used for bearings). If there is any type of leakage in the seals then vacuum should pull the oil inside but here water is getting mixed with oil.

 

Please give your valuable suggestions to resolve this issue.

 

Regards,

 

Attached Files

•  Schematic circuit.pdf   50.25KB   5 downloads
•  Root Blower being used.jpg   5.32KB   0 downloads

[Dazzler]

Hi Asif Aziz, 

 

I have worked at some resin plants in the past with reactor "head gear" for vacuum etc.

 

A few thoughts:

• Have you talked with roots blower vendor?
• Have you tested the oil so be sure it is water or could it also be solvents from reactor contaminating the oil?
• Is the condenser working?  Perhaps cooling or process side is fouled?  Even if it is condensing well perhaps the vent gas is still too hot (or too cold (see below) for the roots blower?
• Is hot saturated reactor vapours bypassing the condenser via the KO Pt drain legs?  
• Are the KO pots working effectively for droplets/ mist?  ie tangential entry, no fouling or buildups disruption flow, demisters in place, liquid level no too high, or foam forming and carrying over ?  
• Some plants my have a second condenser.  So the first is partial condenser and then a second in series is a final condenser.  
• If you run different batch types, some formulations may have vapours that are more troublesome than others for condensing or effect on the oil?
• Different oil may be necessary in root blower?
• When the system is stopped, hopefully no liquid form liquid ring vac pump is flowing backwards?
• Is the roots at a low point in the piping, and between batches  the moisture on walls drains to the root blower?
• Perhaps in piping down stream of the roots blower heating is needs so that any vapours do not condense on cool surfaces, but instead can pass straight through the blower?

Do let us know what you find out so we can all learn from the real world/plant.......

 

Dazzler

Edited by Dazzler, 01 April 2017 - 01:26 AM.