2 replies to this topic

[aliadnan]

HI...
I want to know what is the importance of L/D ratio in the design of reactors, vessels dryers and other equipments. I would be very gratefull for your help

Regards

[siretb]

It is difficult to give a general answer to your question, but the l/d ratio is Very important

Firstly, on a chemical engineering viewpoint, the larger the l/d, the closer to a plug flow behavior you will have. Very often, but not always a plugflow reactor is preferable to a perfectly mixed reactor (CSTR).
With a large l:d, also, for a given volume you increase the wall area, thus facilitating heat dissipation.

Secondly, you have economics. It is also clear that for quite large vessels or reactors a large l:d (cigar-like shape) is more expensive.

There is no clear cut answer. For a reactor the preffered choice depends on the kinetics of all the reactions, including the unwanted reactions. For a vessel a l:d of 2 to 3 is a good ratio.

[Ankur Shah]

also,

if u have a higher L/D ratio for a packed bed reactor, u will induce higher pressure drops across it.

to get a proper L or D, u will need to optimise for the economics, the operation and the requirement of the system.

Ankur