Three flexible PVC sheets were evaluated to determine their suitability as liners to protect existing steel tanks handling treated brine at 55°C in a membrane technology Chlor- Alkali plants. The evaluation included: characterization of liners and plasticizers (by Soxhlet technique, Infrared Spectroscopy (IRS), Secondary Ion Mass Spectroscopy (SIMS) and Gel
Permeation Chromatography (GPC); quantification of brine pollutants by Atomic Emission Spectroscopy (AES) and weight-loss/volume ratios; observation of the superficial damage produced by extended immersion in acid hot brine by Scanning Electron Microscopy (SEM); and the estimation of remaining properties in high temperature oxidative atmospheres (per ASTM D 30451). As a result of this evaluation, remaining property curves as a function of time and temperature are presented for high temperature atmospheric exposure. These curves are related to actual service and to changes in liner hardness. Economics of using flexible PVC liners are compared to flakeglass filled thermosetting coatings. The conclusions are that, even though flexible PVC linings are disposable, they protect steel against hot acid brine corrosion, and they
are economically attractive compared to flakeglass filled coatings. In addition PVC linings may be more reliable because remaining PVC properties can be measured using nondestructive hardness measurements. PVC linings are not recommended above 65°C in corrosive service because life is notably reduced.
Keywords: PVC, lining, acid brine, life prediction, contamination, leaching, plasticizer