PRETREATMENT FOR VAPOR COMPRESSION STILL

[funsharer]

I 'M A SYSTEM ENGINEER WORKING WITH A BIOPHAM COMPANY.
OUR WATER TREATMENT SYSTEM IS UNDER CONSTRUCTION LIKE BELOW;

CITY WATER(QUITE QOOD)--> SOFTENER(DUAL) --> STORAGE TANK
---> AC FILTER(DUAL) ---> VAPOR COMPRESSION STILL(ACUACAM)
----> HWFI STORAGE TANK

I BELIEVE IT IS A GOOD IDEA TO PUT A DEPTH FILTER RIGHT AFTER AC FITLER TO BLOCK SOLIDS EVEN THOUGH I KNOW THAT THE WATER QUALITY IS GOOD AND SOLIDS DO NOT HAVE MUCH EFFECT ON VCS. BUT SOME OF MY COWORKERS & STILL VENDOR SAY THAT AC FITER AND SOFTENER ARE JUST ENOUGH FOR PRETREATMENT AS THE WATER QUALITY IS GOOD.

WHAT WOULD BE BETTER IN THE LONG RUN? PLEASE HELP ME WITH THIS. THANK YOU.

JOHN

 

[quark]

If your suspended solids are below 5 ppm, you should not have problems. By vapor compression still, do you mean a multicolumn distillation still?

In that case you should take care about the ACF. I think the reason for placing ACF after softner is to take care of residual chlorine. If your ACF is not working properly (if pores get clogged) you will face corrosion problems with your MCDS. The recent trend is to use SMBS dosing instead of ACF as ACF is a breeding ground for living organism and it is a head ache to steam the ACF periodically.

Try to maintain water conductivity below 5 microsiemen/cm before MCDS otherwise it is difficult to get good quality of WFI.

Regards,

 

[GarySCWSVI]

If the purpose of the ACF is to take care of chlorine I would locate it before the softener as chlorine will damage the resin in the softener. With the ACF after the softener the resin in the softener will reduce the chlorine content by the chlorine oxidizing effect on the resin.

You should ask the vendor what the purpose of the ACF is. If it is to filter particulate then I would suggest a Depth Filter instead of the ACF. If it is to filter organics then its location after the storage tank is okay.

Gary Schreiber, CWS VI
The Purolite Co.

 

[quark]

I was presuming chlorine (or hypochlorite) addition after softner.

Regards,

 

[funsharer]

Thank you , Quark & Gary.

For your reference, it is not a MES( multi effect still), but vepor compression still made by Acuachem in US.

My concern is whether we need a prefilter(5micron) in between ACF & the storage tank when the water quality is good. I am aware that there are pros and cons where to locate AFC & softener.
Please advise.

Another question for Quark, what are MCDS & SMBS short for?
Please let me know.

Thank you for your kind help.

John

 

[quark]

I did a search about vapor compression stills and it seems the design can take care of your suspended solids problem. But you didn't indicate your feed water quality.

MCDS - Multi Column Distillation Still
SMBS - Sodium Meta BiSulphite

If your storage tank is not of SS then your softner should be after storage tank.

For other things I will agree with Gary.

Regards,