Polygon Provides Dry Air

A 500 MW power plant was scheduled for a nine-month offline maintenance project. The goal of the maintenance was to increase the size of the precipitator to improve particulate removal and meet clean air legislation requirements. Having previously trialled dry air layups during maintenance periods, the utility company contacted Polygon to provide dry air protection for the duration of this major project.

Challenges

Initially, dry air protection was needed for the water/steam side, the air/gas side, and the penthouse above the generator. As work progressed, condensation was discovered collecting in the generator housing, requiring an adaptation of the system to protect the generator as well. In any dry layup process, the complete removal of water from the system is critical to avoid corrosion and damage to sensitive components.

Solution

Polygon designed and implemented a dry air protection system tailored to the specific requirements of the plant. As the unit was taken offline, Polygon technicians began draining the boiler, while plant staff applied nitrogen to displace oxygen and protect internal components while water and condensate remained.

Once drained, the boiler was fired and maintained until all remaining moisture was eliminated. The crew then methodically drained each system, vacuuming and mopping low points to ensure complete water removal. When all systems were dry, dry air was introduced and circulated through the entire plant. Dehumidifiers were activated, and airflow was continuously monitored throughout the system to ensure effective protection.

Result

The maintenance work, including repair, expansion and replacement of key components, required full access to all parts of the unit. Using dry air instead of nitrogen or a wet layup enabled unrestricted access and a safer working environment. The entire maintenance project was completed on time and without incident.

Benefits

Polygon’s dry air protection enabled continuous, monitored drying of critical systems, ensuring safe and efficient working conditions. Unlike nitrogen blankets or wet layups, dry air allowed easy access to all components throughout the maintenance. The system effectively prevented corrosion, supported environmental compliance, and contributed to the successful, timely completion of the project.