3 replies to this topic

[antator]

I have a situation where I have several tanks (approx. 10m in height and 15m in diameter) that need to be heated, it is required to heat these tanks externally using LP steam in shell-and-tube heat exchangers (Each tank will have one heat exchanger).

Obviously, it is easy to calculate the heat duty of the exchangers by calculating the heat loss from the tanks. However, it occurs to me that it doesn't matter what heat duty you have if the recirculation system does not thoroughly mix the tank. As such, can anyone help me in working out the recirculation rate that would result in good mixing, are there any good references / rules of thumb for calculating this?

To me it seems that in order to do this accurately you need to specify your tank, and then specify your mixing eductor system to calculate the motive fluid flowrate required. What I'm trying to do at present is obtain a ballpark figure of what the motive fluid flowrate may be with specifying by mixing eductor(s).

[ankur2061]

Antator,

You may look at the following link to get a pathforward to your query:

http://www.cheresour...__1

Regards,
Ankur.

[breizh]

Hi ,

Attached a reference which may support your query :

http://www.s-k.com/p.../pro_01_04.html

Hope it helps

Breizh

[pawan]

Since you are looking for a thumb rule figure I suggest general consideration where 3 vol changes in the tank are considered sufficient for homogeneous mixing. Now time required for this from your process side will determine the flow rate of mixing device.