Corrosion and erosion are two of the most persistent threats to the integrity of industrial infrastructure, particularly in coastal environments where moisture, salinity, and operational stress converge. At a major coastal Thermal Power Station in India, these factors had severely compromised the Circulating Water (CWC) Pipelines. Left unaddressed, the degradation posed a significant risk of unplanned shutdowns and high maintenance costs.

Recognizing the urgency of the situation, Arudra Engineers Pvt. Ltd. was entrusted with the comprehensive rehabilitation of the CWC pipeline system. The solution deployed centered around Duromar®’s 100% solids (Zero VOC) polymeric epoxy technology — a high-performance, environmentally responsible coating system known for its exceptional mechanical and chemical resistance.

Project Scope and Challenge

The CWC pipelines, both internally and externally, were exhibiting advanced stages of corrosion and erosion. These pipelines, which serve as critical ducts for the continuous flow of seawater for cooling operations, are under constant exposure to highly aggressive conditions. Traditional repair methods were no longer sufficient to offer long-term protection.

Arudra’s approach was to not just repair, but fully restore and future-proof the pipeline system with a solution that offers structural reinforcement and superior corrosion resistance — while ensuring the system remained as close to original operational specifications as possible.

Internal Rehabilitation Strategy

The internal pipeline refurbishment began with the complete removal of the existing cement mortar lining, which had deteriorated beyond repair. A meticulous surface preparation followed, achieving SA 2.5 cleanliness standard through abrasive blasting to ensure optimal adhesion of the coating system.

A solvent-free epoxy build-up was applied to restore the internal lining thickness to approximately 5 mm. This layer served as a structural rebuild, compensating for material lost due to erosion.

Following this, Duromar® HPL 2131 — a high-performance, solvent-free epoxy coating — was applied at 4 mm thickness. This material is specially designed for immersion service in aggressive chemical environments, offering superior resistance to corrosion and mechanical wear.

A final topcoat of Duromar® HPL 2510 was applied at 1 mm to provide a smooth, low-friction surface that enhances hydraulic efficiency and ensures long-term durability under continuous water flow.

External Rehabilitation Strategy

Externally, the pipeline system had suffered extensive atmospheric and splash-zone corrosion, requiring an equally rigorous restoration process. Surface preparation to SA 2.5 standard was carried out to eliminate rust, scale, and contaminants.

The application of Duromar® SAR — a ceramic-reinforced epoxy putty — followed, with a build thickness of 4 mm. This material is engineered to rebuild and protect surfaces subjected to high abrasion and impact, making it ideal for the harsh conditions in coastal power stations.

To further reinforce the structural integrity, a specialised wrap system was applied over the cured putty at 1 mm thickness. This added layer served both as reinforcement and as a barrier to environmental exposure.

Finally, a topcoat of Duromar® HPL 2510 was applied to ensure robust protection against seawater corrosion, UV radiation, and fluctuating weather conditions — all common in coastal zones.

The Outcome

The pipeline restoration project not only recovered the lost mechanical strength and dimensions but also significantly improved long-term corrosion resistance. The Duromar® system ensures a low-maintenance solution with high uptime reliability — critical for power plants operating on tight schedules and limited shutdown windows.

With this rehabilitation, the plant avoided the need for complete pipeline replacement, saving both time and capital expenditure while ensuring compliance with environmental and operational safety standards. One of the most significant advantages of the solution is its low-maintenance nature. The Duromar® coatings are engineered for extended service life with minimal need for future intervention, allowing plant operators to maintain high uptime reliability.

Commitment to Innovation and Collaboration

This project was executed in technical collaboration with Duromar Inc., USA. Arudra Engineers Pvt. Ltd. serves as the licensed manufacturer, distributor, and applicator of Duromar®’s complete range of high-performance coatings and repair systems in India.

By combining advanced polymeric technologies with field-tested application expertise, Arudra continues to support India’s critical infrastructure sectors — from power generation to heavy industry — with solutions that are both durable and environmentally responsible. In summary, the restoration of the CWC pipelines not only addressed existing damage but also upgraded the asset to a higher standard of durability and environmental compliance. It stands as a strong example of how advanced materials science, applied with precision engineering, can extend the lifespan of critical infrastructure — economically, efficiently, and sustainably.

Arudra– in technical collaboration with Duromar Inc (USA) – is a licensed manufacturer & applicator of Duromar® epoxy coating & lining products.