6 replies to this topic

[process.eng]

Can someone please urgently provide me the Fouling Factor or Coefficient For Ethylene Oxide ?

I can't find it online.

Coulson Richardson Vol.6 quotes typical value of 5000 W/m2 degC for organic liquids and vapours

Is it an appropriate estimate for Ethylene Oxide ?

I wish to know which one is more fouling : Steam (Used In Condensing Mode) or Ethylene Oxide

[Zauberberg]

At first, what you have quoted for the fouling factor is not possible. The units used for FF should be reciprocal to the units you have used in your post.

Secondly, fouling factors are in the range of 10E-05 to 10E-02 (m^2-C/W) and not hundreds or thousands. This more likely refers to the heat transfer coefficient (or film coefficient), not the fouling factor. The units used are indicating this as well.

Finally, there is no doubt that steam is the cleaner fluid, or at least less prone to fouling than Ethylene Oxide which is reactive component and may undergo degradation, polimerization etc. within the heat transfer equipment.

I would suggest you a thorough reading of dedicated chapters from D.Kern's "Process Heat Transfer" to give you completely clear picture about the subject - heat transfer, heat transfer coefficients, and fouling factors. A lot of information is available on the internet as well.

[ankur2061]

There is an excellent table (Appendix VII) at the following link about fouling resistances:

http://www.chemstati...icles/shell.pdf

Regards,
Ankur.

[latexman]

When you decide on a fouling factor, what you are actually doing is deciding on how frequently that heat exchanger will be cleaned, i.e. a maintenance schedule, and at what production level you will run. If someone gives you a fouling factor, you are getting their maintenance schedule. You may want to understand their maintenance schedule, cleaning methods, and production level before you use that fouling factor for design. It is a major decision that can impact profitability very much!

[process.eng]

Can someone please urgently provide me the fouling factor for Dowtherm A ?

[fatimah]

Hi there

as long as i knew, the unit for fouling factor is m2. degree C/W and not as W/m2 degC. just want to check with you if you refer to the wrong value.

[Art Montemayor]

Studentsphere:

First you "urgently" need a fouling factor for Ethylene Oxide (EO) and then one for Dowtherm.

What is obvious about your needs is that you urgently need to reflect on what advice you have received from Zauber and Latex: concentrate on reading and learning about what exactly a fouling factor is and how it is meant to be employed. You have missed the whole point about a fouling factor.

Strictly speaking, neither pure EO or Dowtherm will cause any fouling. What does cause fouling in a heat exchanger is decomposition by-products (in the case of EO), contamination, or impurities in the parent stream. Rusting of the exchanger tubes is not a fouling. It is a resistance caused by oxidation of the parent metal. As Latex has explained, all this specific knowledge goes towards affording the operator a means to deal with eventual maintenance or cleaning of the exchanger. Often times - as in the exchangers I've designed and operated - there is no fouling factor employed at all. I have done this by applying simple, practical rules on shell & tube velocities as well as exchanger geometry. I have explained all this in another thread which you and others can find by using the SEARCH feature on the Forums. I have submitted a copy of an excellent and classical article that fully explains how to deal with or avoid fouling factors altogether.

Good Luck.