rule for selecting fouling factor

[kyong]

Hi,
Is there any code rule for selecting fouling factor when designing shell & tube heat exchanger?
Similarly, is there any rule for selecting allowance for roughening/plugging of tube inside surface when calculating head loss along tubes of shell and tube heat exchangers?
Any comments would be appreciated.

 

[TD2K]

TEMA has quite an extensive list of suggested fouling factors in the back of their standard but ultimately, you need to review those to ensure they are applicable to your service. Use them as a starting point. I've worked in plants where they have gone with the TEMA #s in some cases, used higher or lower ones in other cases based on their experience.

The fouling factors do not in themselves affect the pressure drop calculations through the tubes/shells. If the deposits are thick enough to have that effect, you'll need to tweak some other parameter to handle that but I don't know how that is done. Anyone else? I don't think I've seen a 'clean' and 'dirty' dP on an exchanger data sheet.

 

[MJCronin]

kyong,

I suggest using field data whenever possible...

If there are similar heat exchangers i similar service, back calculate the "operating" or actual fouling factors and use this as a basis for your decision.

Some heat exchangers provide acceptable service with regular cleaning schedules. Remember, the maintenance people would love to have huge exchangers that the clean less often......... however, the people who price the capital projects would, of course, love to pay for much smaller units

Just some thoughts......

MJC

 

[kyong]

TD2K, MJC,

Thanks, your comments helped me.

kyong

 

[Shahin71]

Hi

There is a good article in CEP magazine

"TO FOUL OR NOT TO FOUL,That is the question" November,2001



Hope this helps

Shahin71