TP26-12 Development in Non-Azole Chemistry with Low Toxicity for Copper Corrosion Inhibition in Open Recirculating Cooling Systems

Recirculating cooling systems commonly use copper metallurgies for heat exchanger tubes due to the favorable heat transfer properties. Traditional corrosion inhibitor treatments utilized the benzotriazole family of chemistries: benzotriazole (BZT), tolyltriazole (TTA), chloro-tolyltriazole (ClTTA), and butyl-benzotriazole (BBZT). Utilizing these benzotriazole compounds requires accepting their fluctuation in pricing, supply chain shortages, and more recently, tariffs. More importantly, benzotriazole chemistries present unfavorable aquatic toxicity profiles compared to other conventional cooling water treatments such as salt inhibitors, dispersants, and phosphorus chemistries. Several European countries have started to restrict or ban their use in industrial applications, and effluent discharge toxicity limits have led operators to look for alternative solutions. Recently, a true non-azole solution for use in industrial recirculating applications was presented by Sui et al. This new approach delivers a non-toxic and biodegradable solution to replace benzotriazoles as the copper corrosion inhibitor, without loss in protection performance. Presented here is a continued evaluation of the non-azole solution utilizing surface analysis to understand the passivation process and an in-depth review of successful field trials under industrial cooling conditions.