In thermal power plants, the corrosion of main equipment can cause major safety hazards and economic losses. Thus, it is very important to take proper maintenance for thermal equipment in power plant during shutdown. A maintenance method of hot air combined with vapor phase corrosion inhibitor was developed for the water vapor system of waste heat boiler in the 9F class gas-turbine combined cycle generation unit. The protection for the thermal equipment was achieved by reducing the inner moisture and injecting vapor phase corrosion inhibitor. The design and implementation of the shutdown maintenance system were described in detail. The actual operation of this maintenance in electric power plant shows the advantages of low cost, simple operation and high protection efficiency. The maintenance of hot air combined with vapor phase corrosion inhibitor has the great guiding significance for the protection of thermal equipment and other related machinery during shutdown.
