1 reply to this topic

[Ghasem.Bashiri]

Dear Sir, Madam
Within one project owner asked from us to consider fouling factor for air side of heat exchanger which is equal to sea water fouling factor recommendation in TEMA.
I am going to check effect of such fouling factor on over design of exchanger. For information 10-15% additional overdesign should be considered as per our design basis also.
I checked API 661 standard datasheet that does not contain input data for Air Side fouling Factor. Is it required to consider such item for thermal rating of heat exchanger?
What is effect of this parameter on overdesign of heat exchanger?
Do you have any practice? if yes let me to have a copy of it!
Best Regards
Ghasem.Bashiri@gmail.com

[smalawi]

Dear Sir, Madam
Within one project owner asked from us to consider fouling factor for air side of heat exchanger which is equal to sea water fouling factor recommendation in TEMA.
I am going to check effect of such fouling factor on over design of exchanger. For information 10-15% additional overdesign should be considered as per our design basis also.
I checked API 661 standard datasheet that does not contain input data for Air Side fouling Factor. Is it required to consider such item for thermal rating of heat exchanger?
What is effect of this parameter on overdesign of heat exchanger?
Do you have any practice? if yes let me to have a copy of it!
Best Regards
Ghasem.Bashiri@gmail.com

Hi,

Typically only the process side fouling is specifed and it should be representative of both air & process. The air side is considered stable and does not vary significantly unless you have very fouling air side conditions. The overall foulign factor will simply increase your required area for a given design, its another safety factor.

You can check with manufacture standards (Hudsen / GEA.. others), you can contact them directly in case of new purchase / query.

Depending on which software you use (HTRI / HTFS ... other) you will be able to fine more info on fouling in air coolers service. HTRI has very good sources, but its linked to the license server.

If you work in a refinery, suggest to check similar service, if you work in an engineering company, check your standards. The TEMA standards can be way off (many articles on the web on this subjet)

Be maindfull when you look at design margins, they are not overdesign, they are margains for flexible design to enable good control / operation. This is needed in any good design as the feed / product compostions will vary and so if the flow rate. Fouling factor is a saftey margin to account for fouled conditions or accuracy of the correlation used in sizing. Do not include unnessesary high fouling factors as the air fan size will expan quickly making the cost extermly high. There is a point where you need two banks and more area means another bank with fans / fondation ... etc

Hope this helps,

Regards,

sm