Quench tower with two sections: packing and trays 1

[zorn]

Hello,

the attached image represents a quench tower installed at the end of a Claus tail gas treatment unit. It's divided in two sections and it has two recycles. The lower recycle takes part of the bottom water (sour water) and recycles it on the 7th tray, the upper recycle takes the water from the chimney tray and recycles it on the top. What do you think about using trays in a section and packing in the other one?Why did they do so, maybe for avoyding pressure loss?

thank you,
ZorN

http://img3.imageshack.us/img3/4901/aaawa.jpg

 

[ATMChemE]

If you want to, I can help you take a look at this example. You can reach me at ATMChemE@yahoo.com

 

[zorn]

Another question in the same image:

does the chimney tray permit the liquid to go down, to the tray below?

 

[sshep]

Hey zorn,

I couldn't see your picture for some reason, but I think the answer is this: Trays will be less likely than packing to foul up, so they are in the bottom as a wash section to handle the dirtiest water. If the packing were used first, it could foul easily, then you would see a high pressure drop.

just a guess from experience,
sshep