A Corrosion Protection Methed for Preventing Corriosion Due to Inner-Jumping Current in High-Temperature, High-Pressure Water Pipelines
Akinobu NISHIKAWA and Hidemasa NONAKA
Abstract:Cathodic protection is being applied to buried heat supply pipelines in district heating and cooling systems. However, there is possibility of corrosion due to the inner-jumping current occurring at insulating joints. In this study, a corrosion protection method which makes the bare pipe behave as if it were coated on its inner surface with resin or a resin tube was developed and evaluated. This method utilizes the behavior that the passivity of corrosion-resistant material restrains the outflow of current from its surface. As a result of various experiments, it has been found to be most effective to use a pipe made of titanium with insulating joints at both ends for reducing the inner-jumping current. This corrosion protection method has already been adopted at worksites and confirmed in its effect. Key Words:District heating and cooling system, Inner-jumping current, Titanium pipe, Corrosion protection