5 replies to this topic

[Atthu]

Hello Everyone.. This is my first post in cheresources.com

 

Coming to the point, a 5-effect falling film plant is installed at our site. The plant is running well, achieving the designed reject concentration except the problem given below:

 

"Surface condenser water is colored and have a high tds of around 9000 mg/l - a issue of concern as this condensate is to be fed to boiler shell in future."

 

I would like to know what causes the tds in the surface condenser water to rise this much..

 

Details about 5-FF are:

 

Temperature profile - 90 deg C, 82 deg C, 77 deg C, 72 deg C, 62 deg C (design 49 deg C).

 

water is flashing in the 5th vapor separator whereas it is not the case in other separators... 

[Bobby Strain]

Obviously you have an entrainment problem. Or leaking coolant. I don't understand your last statement. It seems to me that flashing occurs in all effects. You didn't mention tds in other effects. Should we assume that they are all within specification? What are you feeding? How much concentration is accomplished? Maybe a drawing of at least the final evaporator would help you get response. Along with more process information.

 

Bobby

[breizh]

Hi ,

Can you share a PID of your units , are they all equiped with mist eliminator ? Are you sure about your instruments , temperature and pressure ,are they well calibrated ......,?

Recovery of condensate is always complicated .

What is your expectation for entrainment ?

 

A few pointers .

Good luck

 

Breizh

Edited by breizh, 21 January 2016 - 10:59 PM.

[Atthu]

Thank you Mr. Bobby and Mr. Breizh...

 

Flashing occurs in all effects, but it seems that the concentrated liquor is getting carried away towards surface condenser in the 5th effect.

 

Condensate TDS is well within specified limits of 500 mg/l.

 

Feed water is RO reject with 5% concentration.. The design concentration of 30% is successfully accomplished in the last effect.

 

All instruments are installed in parallel to physical gauges showing same and exact readings.

 

Please find the P&ID below...

 

 5-FF.pdf   190.35KB   364 downloads

[breizh]

Atthu,

Thanks for sharing your documents .

How do you manage the liquid  flow from one unit to the other or how do you manage the level in each effect ?

It seems to me that none of your separators are equipped with demistor , am I right ?

 

Breizh

[Atthu]

Thanks Mr. Breizh for sharing literature about mist eliminator.. No sir, we have not installed any mist eliminator.. Level sensor installed in every effect... Which facilitates level maintenance.