Design - Quench tower

[misterd]

How do you size a gas quench tower. We have to design a quench to cool down hot air (420 F) to 140 F. This would be done using water injection. What diameter for the quench? length? Rule of thumb for residence time?...

 

[25362]

Look for Donald R. Woods book titled Process Design and Engineering Practice published by Prentice Hall. You may find it has all the information you are looking for. Good luck.

 

[tkdhwjd]

It is not a simple design.
First you must decide what tower internals you are going to use... ex. packings, trays, etc. For quench tower, generally packings are used.

Here are my suggestions...

1) For brief simulation, use a series of flash drums to see how many equivalent stages are required to meet the target temperature.

2) Then deicde which packings to use based on vapor and liquid flowrates at each stage. You should make sure your packings will not flood. At this stage, you can adjust/optimize a tower diameter.

3) Calculate required height of heat transfer section, from which you can derive how high the packings must be stacked.


You will also have to provide a quench water drum, where the residence time plays an important role. You can do few rough settling/floating velocity calculations based on your expected oil/solid particle size, water flowrate, and drum dimension. Once again, designing these is very complicated and commonly done by a specialist, unless the existing tower is simply being debottlenecked. It is not an exaggerating statement to say that you can spend a life researching/designing quench tower only.

 

[PeterAB]

The quickest and simplest way to quench is with an air-atomized spray nozzle. See

http://www.turbosonic.com

Peter Brekelmans