Material Of Construction For Caustic Absorber

i have designed a absorber for the removal of SO2 from ethanol,ether and water mixture using dil.NaOH solution.reaction product is NaHSO3.
inlet gas temperature is 128 C
outlet =========== 80 C
inlet solution temperature is 25 C.
outlet may be at any temperature.
design pressure is 1 atm.
tower is packed with 1 in ceramic intalox saddles.
tower dia is 3.6 ft.and height is app.20 ft.
plz seggest me any suitable material of construction for this absorber under these process conditions.and also give some reason for ur nice answer for this.
my email add is
secretpearls33@hotmail.com
secretpearls33@yahoo.com
pleaze, guide me in this problem.
Muhammad Naeem
(final year Chemical Engineering)
(Engineering University,Lahore,Pakistan)

Dear Mohammed
You havent mentioned the concentration of the SO2 .
At 128 deg C, the SO2 is in the dewpoint zone already and the choice material of construction will not be carbon steel .
I would use SS316i. It is not too expensive and has good corrosion resistance to the product gases you are working with.

Dont forget to consider foaming problems. You might want to fit a demister at the top. Knitted filament of polypropylene is a popular solution to minimise entrainment.

Ahmed Vawda
HOD Teh Services
www.unitedsugar.com