4 replies to this topic

[Supriyo Mukherjee]

We were dealing with a Evaporation Cooler.

 

This consists of a packed bed in which water gets cooled by incoming dry air.

 

Water falls from top to bottom. Air from bottom to top and vents to atm. Here the air is around 67% Nitrogen rest Oxygen.

 

The packed bed here was of 1.5 " Polypropylene Pall ring material.

 

When it was commisioned the bed was processing 6490 NM3/Hr of dry air of above composition. The pressure drop across bed was 10 millibar.

 

After one year of operation and a shutdown (which was done by client) the pressure drop has increased to 100 mbar and it is hardly taking around 3500 NM3/Hr. 

 

We suspect some foreign material has went into it during shutdown. 
We are opening the tower for inspection by taking a shutdown to find out the exact reason.

 

Before hand it will be very helpful to know if any group members has any idea of this kind of problems. Iam talking about a closed system Heat excahger- EVC precooling system for air separation units.

 

I will update hte findings after the inspection.

 

Thanks and regards..

 

 

[GHartmann]

You have chosen the most likely cause.  Have you evaluated your water circulation rate to determine if packing flooding conditions can be achieved?

[Supriyo Mukherjee]

Thanks for prompt reply.
At this moment after around five days of hard work what we found is the tower packings; internals all are choked with a material. The material has went for lab testing. About the flooding check. Yes we had checked earlier the flow rate and hydraulics for the packings never showed flooding.
Thankfully after restarting the problem is solved now and the pressure drop has been well less than 5 millibar.

[breizh]

Hi ,

Just curious , did you have in place or perform any chemical treatment and blow down to eliminate the deposit ?

 

 

Breizh

Edited by breizh, 17 November 2014 - 04:59 AM.

[Supriyo Mukherjee]

Thanks Mr. Breizh for putting forward a very important point regarding this. 
I am sorry I could not reply earlier due to my other commitments at the year end. 

I have gone in details for the analysis. The treatment was not proper and I have suggested proper treatment for the system concerned.