3 replies to this topic

[malikch06]

dear viewers!
i' m having a problem in hydraulic calculations of thermosiphon reboilers, any one having the idea of thermosiphon working criteria, please assist me...

Sohail Malik

[Zauberberg]

In absence of any corporate (process) design standards, I'd suggest you to obtain at least one of the following resources:

1. D.Kern, "Process heat transfer"
2. E.Ludwig, "Applied process design"
3. R.Serth, "Process heat transfer"

In addition to that, browse these forums - I remember a lot of topics dedicated to thermosyphon circulation.
Some help from Google:

http://tx.technion.a.../LECTURE_08.pdf

[malikch06]

i'v studied ur linked article,, my concern is regarding the thermosiphon reboiler working criteria, which in this article is stated as:: the pressure drop due to frictional losses must be equal to or greater than the pressure drop due to the density difference(termed as driving force),
in common sense, driving force must be greater than resistive forces, but here the case is reversely stated,
please explain this ambiguity

Eng. Sohail Malik

[Zauberberg]

Actually these two forces (the driving and the resistance force) are equal, in any point of time in reboiler operation. More heat --> more vaporization --> lower density in reboiler return line --> higher driving force, but also higher frictional losses due to increased flow through the reboiler. As simple as that.

Not sure what the author was thinking by this sentence, but the equations given - as long as you use the equation sign between the driving and the resistance forces - are correct.