There is a practice of filling sulphur di oxide liquified in tonners/cylinders normally used for liquid cylinders . Being corrosive gas additional safety is alwayas better.Many of the filler are using old /used cylinders for the purpose. liquid chlorine design pressure is higher 19.9g/cm2.Bases on vapor pressure of Sulphur di oxide desigin pressure can be reduced.But still i suggest you to use chlorine tonner design for safety reasons. You can approach the tonner manufacturer INDIAN SUGAR AND GENERAL ENGG COMPANY YAMUNAGAR -HARYANA,Concerned person contact no is 09996048709.
DETAIL DESIGN DETAIL OF CHLORINE TONNER/CYLINER IS ATTACHED.
CYLINDER/TONNER IS THE NOMANCLATURE BESED ON ONE TON QUANTITY IN IT. ANY VESSEL LESS THAN 1000 LITRES IS CALLED TONNER/ CYLINDER