Corrosion and abrasion damage to plant and manufacturing equipment has long been a problem in the Pulp & Paper industry. The basis of remaining productive is ensuring equipment is maintained to allow seamless and uninterrupted operation. Therefore, companies must formulate and adopt corrosion control processes for production and finishing alongside flooring and containment. When each of these aspects is considered and addressed, it will vastly reduce the likelihood of contaminated paper, damaged machinery and regulatory violations, which impedes business and productivity. It will also reduce the possibility of health and safety risks for workers posed by faulty equipment and the surrounding environment, contributing immensely to the company’s bottom line.
Where are Corrosion and Abrasion Most Likely to Occur?
When producing pulp and paper, many production aspects can expose materials and machinery to corrosion and abrasion. The environments can be extreme, with high impact and wear, a standard element of operations. Plants may include digesters, evaporators, recovery boilers, bleaching apparatus, paper-making machines, rollers, and chemical storage tanks. Corrosion can become an issue in any of these and even throughout the entire facility – from pipework, floor and wall surfaces, and any other mechanisms that operate in the environment.
Types of Corrosion Commonly Found in Pulp & Paper Mills
Various types of corrosion and abrasion are found in Pulp & Paper mills. However, those most observed include stress corrosion cracking, uniform corrosion, and crevice corrosion. Each of these can exhibit many variations – the variety will feature in Part 2 of this series.
Stress Corrosion Cracking
A combination of material, mechanical stresses and environment causes stress cracking. These cracks can spread and lead to catastrophic failure. Combining mechanical stress and any corrosive environmental elements can cause stress corrosion cracking (SCC). SCC can be unpredictable and dangerous, associated with high failure rates as it may occur without warning – in severe cases, within hours or days. SCC is considered an insidious form of corrosion that contributes to rapid loss of mechanical strength leading to fractures and catastrophic failure. Stress might result from applied forces during manufacture, fabrication, and heat treatment, but it can also be from rapid temperature changes or uneven contractions.
Uniform Corrosion
Uniform corrosion often occurs in the presence of alkaline solutions and molten salts, where the passive layer that protects the metal breaks down across the entire surface. Sometimes known as generalised corrosion, this type will affect an entire surface exposed to the corrosive environment and destroy the whole or a large part of an unprotected surface. While destructive, this type of corrosion is less dangerous as it occurs uniformly and leads to predictable degradation. It is also easy to avoid when durable surface protections are implemented.
Crevice Corrosion
Crevice and pitting Corrosion are like uniform corrosion but are usually limited to smaller areas. It is common in almost all industries as it often occurs in engineered and mechanical equipment and causes non-uniform corrosion formation in any unprotected crack or crevice. Crevice corrosion depends on environmental factors such as alloy resistance, crevice geometry, and any imbalances in the pH levels. It’s also easy to miss on inspection, which makes it a necessary corrosion form to be aware of and check for.
Solution
The best way to identify which product would suit your requirements for corrosion resistance is to consult a Chesterton® product expert. However, certain products are used extensively throughout the Pulp & Paper industry and are known to provide reliable corrosion resistance. One such product is Chesterton’s ARC Industrial Coatings. With four decades of proven high performance and engineered to protect metal and concrete from damaging abrasion, erosion, and chemical attack, the coatings are a solid choice for essential equipment and structures. One popular coating for the Pulp & Paper industry is ARC S1HB. This single-coat, low VOC barrier has high-build, edge-retentive properties to maximise coverage over hard 90° and sharp edges with minimal thinning. Most importantly, it is resistant to various corrosive agents.
ARC Coating Case Study
A Chesterton Pulp & Paper client in Malaysia suffered from extreme wear in their Cyclone due to abrasive material flow. 24-hour operations and abrasive, slurry medium containing scrap pulp and metal stapler bullets caused the existing competitor coating to fail within 3 months. The client sought a coating lasting over three months without service or maintenance. The local Chesterton expert applied ARC BX1 and ARC SD4i. After 6 months of operation, an inspection showed that the coating still looked almost new. As a result, the customer was delighted and sent more equipment for repair with Chesterton coatings. To discover more, read the entire case study here.
Discover Solutions from Chesterton®
Pulp & Paper plant operators can ensure industrial compliance and equipment longevity by increasing their knowledge of common corrosion issues and taking preventative steps to avoid failure while incorporating preventative protective coatings and monitoring equipment to stop it. Different corrosive and abrasive environments require different solutions, so the best way to identify what best suits your needs is to consult a Chesterton® product expert. Visit our website at www.chesterton.com or email an enquiry to enquiries_apac@chesterton.com.
This article was featured in Paper Mart Directory.
