4 replies to this topic

Dear All ,
I need your help. WE have a shell and tube condenser with water in tube side and LPG vapours on shell side. There are 1000 tubes 4 passes total. The water inlet and outlet temperatures are about 30 to 40 degree centigrade. Water quality is good. However in every one month we are encountering choking in tubes due to which we require cleaning. The product we get on cleaning is paste like material and is loose bound-appears to be mud like smelly paste. We heated this paste at 60 deg centigrade for 3 hours and 94% of it got lost. What could be this paste. tHE COOLING tower is being cleaned regularly .
Could it be result of some corrosion or chemical incompatibility or some bacterial sludge. How to be sure of what it is/ How to prevent its formation. This is found in last (4th pass) . Pressures on tube side are about 4 Ksc.
Due to this we are unable to condense the vapours and it leads to flare. Any advice pls.
Arvind
sbhit2001@indiatimes.com
Thanks in advance.

[Milutin]

It could be bacterial sludge. It happens in our refinery, because of hydrocarbons present in cooling water (caused by some leaking heat exchanger), plugging of cooling tower. You should check if hydrocarbons present in cooling water.

Regards,

Milutin

[Alawi]

The case you are describing is quite likely to be bacterial sludge , the temp range in the tubes is ideal for bacterial growth, you have not mentioned anything about the velocity in the tubes ,but it is more likely that they are relatively low.
It is very easy to test for bacterial growth in the you lab. Add a few drops of water to a petri dish after adding a layer of Agar leave the petri dish In temperature controlled room and compare the results of bacterial growth to the normal.
What type of treatment program are you using in the cooling towers?

Dear Alawi,

Thanks for sharing the knowledge.

I would be thankful if you could let me know the detailed procedure of test for bacterial growth as I could not understand your instructions.

We are using continuous chlorine dosing in Cooling Towers . In absemce of Chlorine (due to non availibilty of Chlorine cylinders) we use Bactericide slug dosing alternatively.
Waiting for your reply pls.

Arvind Bhatia

[Alawi]

Hi

Things have been made a little more easy for you. Check out “GE Infrastructure water & Process Technologies” they are one of the best in this area, they sell dip slides that you just dip in your water “ cooling water” and check how much bacteria you have. You can also check with “Nalco” also a very well respected company in this area. I am not claiming that theses companies are better then any other, but they just came to my mind.

ALAWI