Bulletin 5002
Sulfonator Materials/Installation Notes

Chemical Injection Technologies
Technical Bulletin
SUPERIOR™ Gas Sulfonators
Materials and Installation Notes
DESIGNSUPERIOR™ Gas Sulfonators are identical in design and function to SUPERIOR™ Gas Chlorinators. All features,advantages, dimensions and specifications contained in SUPERIOR™ Gas Chlorinator literature may beinterchanged for use with SUPERIOR™ Gas Sulfonators.

MATERIALS
Sulfur Dioxide (SO2) in a dry (anhydrous), gaseous state is relatively compatible with a number of common
engineering plastics, as well as most ferrous metals. However, when SO2 comes in contact with moisture (liquidor vapor) it forms acids that can cause serious corrosion to most metals and even some plastics. The samesituation applies to Chlorine as well. In addition, Chlorine and Sulfur Dioxide gases have almost identical specificgravities. Both PVC and ABS plastics have been used for decades with both of these gases, in a vacuum state(below atmospheric pressure) with very good results. Thus, it would seem that a common gas feeding device
should be applicable for both of these gases.
However, PVC (Poly Vinyl Chloride) and ABS (Acrylonitrile Butadiene Styrene) react quite differently to these twogases when they are in their pure liquid state. ABS has proven to be able to withstand a brief exposure to liquid
chlorine, in an unpressurized condition, with little or no noticeable attack. PVC, on the other hand, will be severely
attacked by liquid chlorine. These two situations are reversed with liquid Sulfur Dioxide. PVC will withstand attack
but ABS will be severely damaged by liquid SO2.
Thus, SUPERIOR™ Gas Chlorinators are designed so that the areas which could come in contact with liquid
chlorine are constructed of either ABS or materials that are impervious to any form of chlorine or SO2.
SUPERIOR™ Gas Sulfonators are designed so that the areas which could come in contact with liquid SO2 areconstructed of either PVC or materials that are impervious to any form of chlorine or SO2. These other materials
consist of, but are not limited to, PVDF, Teflon® and Tantalum.

RELIQUIFICATION OF SULFUR DIOXIDEA major physical property difference between chlorine gas and sulfur dioxide gas is the tendency of SO2 toreliquify with a very small change in temperature. It has also been found that SO2 has a greater likelihood offorming small droplets of liquid at the cylinder valve outlet, which are carried into the sulfonator regulator area
without vaporizing, when ambient temperatures fall below 50E F, although high SO2 feed rates can cause somereliquification at ambient temperatures up to 72E F.
It is recommended that Sulfonator installations be made in temperature controlled environments wheneverpossible and practical. When ambient temperatures are likely to fall below 50E F, a heated enclosure is necessary
to avoid operational problems caused by liquid SO2 entering the gas regulator. While reliquified SO2 will not cause
irreparable damage to SUPERIOR Gas Sulfonators, the re-vaporization of SO2 inside the vacuum regulator andmetering areas will create deposits of impurities which will cause operating problems.
Bulletin 5002 SO2 Materials/Installation

Copyright © 1995, Chemical Injection Technologies, Inc., Pub.No. 495-1 Printed in U.S.A.