Paper Machine Dryer and Felt Roll Corrosion, 2010 TAPPI PEERS Conference

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While modest corrosion of carbon steel felt rolls and wet-end cast iron dryers has always been a problem, some producers of alkaline bleached fine paper furnish are experiencing relatively new problems of excessive corrosion of roll surfaces. Operators have also experienced pronounced deterioration in machine fabrics running on corroded roll surfaces. The corrosion problem is apparently due to excessive carryover of residual chlorine dioxide and hydrogen peroxide from the bleach plant onto the paper machine. High levels of these oxidants, exceeding 40 ppm, can be present in the sheet due to increased demand to produce higher brightness paper. Corrosion of mild steel and cast iron roll surfaces is exacerbated by concentration of these chemicals, particularly chlorides, in the “wet-dry” sections of the paper machine. The author describes the metallurgical nature of this corrosion damage, methods used to combat the corrosion problem, and the challenges in refurbishing roll surfaces.