Abstract
Large pressurized steel hot water storage tanks must be protected from internal corrosion, as they have no protective coatings on the water-side. Six pressurized steel hot water storage tanks at an Army installation were chosen for implementation with impressed current cathodic protection systems using ceramic anodes. The tanks, ranging from 5,000 to 13,300 liters (1,300 to 3,500 gal.) in size, are part of a closed loop system that supplies hot water 60°C (140°F) to soldier’s barracks for bathing and to the adjoining mess halls for washing dishes. The tanks will be taken off-line, drained, and holes will be bored in the steel walls to install mixed metal oxide ceramic coated titanium rod anodes connected to a local rectifier and control system. Ceramic anodes have potential to extend the service life of the water storage tank, many times that of the sacrificial anodes, even in corrosive waters.
The design of the system took into account the water chemistry and current density required to mitigate corrosion at a maximum continuous operating temperature of up to 60°C (140°F) in accordance with NACE Standards RP0388-2001 and RP0169-96 for cathodic protection. The benefits of installation of the CP systems are expected to be service life extension of the hot water storage tanks, and reduction in the potential of the tanks to leak and damage other electrical/mechanical equipment. Also, these tanks are located in areas where they would be difficult and costly to remove and replace without breaking through a wall in the mechanical room.
