During the service life of a pipeline, the coating has to maintain its integrity under operating environments and in the presence of cathodic protection (CP). A coating that exposes bare metal areas renders the pipe surface susceptible to corroding species, and a functional CP system will be required. This article discusses the basic principles of corrosion protection with coatings and CP, and the attributes of an effective pipeline coating.
NACE International’s new IMPACT emphasizes how to integrate corrosion technology with management systems to optimize corrosion decisions. For findings related to the pipeline industry, three IMPACT study and pipeline experts answer a series of questions.
It is becoming more common for crude oil or gas pipelines to share their rights-of-way with high-voltage alternating current (AC) power lines. The integrity of AC mitigation facilities is crucial for personnel safety and continued operation of pipelines with effective cathodic protection.
Structures such as steel bulkheads, steel piles supporting piers or wharfs, offshore drilling platforms, and other similar structures may be cathodically protected with either sacrificial galvanic anode systems or impressed current systems.
Some unique capabilities of cathodic protection design methodology are showcased with grillage-type foundations for power transmission structures.
One of the areas where cathodic protection is commonly applied to marine structures for corrosion protection is the steel piling systems on jetties and piers. This article discusses the design and implementation of CP on a newly constructed jetty in Surabaya, Indonesia.
As pipelines age, it is important to verify the effectiveness of the coating and cathodic protection systems that protect them against external corrosion, and implement remedial actions if necessary.
A major U.S. university is using funding from Phillips 66 to develop a new outdoor pipeline integrity lab, which will include buried pipe with an active rectifier to simulate real-life activities.
Due to the high carbon dioxide (CO2) and chloride content in natural gas produced by a gas field in Western China, a high-performance duplex stainless steel was chosen for gas gathering and transmission piping in this area.
The principle of a close-interval potential survey is to record the pipe-to-soil potential profile of a pipeline over its entire length by measuring potentials at intervals that do not significantly exceed the depth of the pipe.
Cathodic protection (CP) is an important component for the sustainability of many metal structures. The most common impressed current voltage sources are rectifiers, which can break down. Well-maintained rectifiers can provide uninterrupted CP, which reduces repair costs and labor/technician time.
The application of CP polarizes steel in the electronegative direction, while raising the pH at the interface at the same time.
Generally speaking, galvanized steel can last for many years in nonaggressive environments, and typically does an excellent job of protecting steel when the structure is located in moderately corrosive environments where oxidizing conditions prevail.
New probe technology developed from recent academic research can conduct safety-critical testing inside galvanizing kettles holding molten zinc at 450 °C.
The measurement and interpretation of cathodic protection (CP) data in plants or other complex facilities present inherent challenges where mixed metals are electrically continuous within the protected structures’ CP system.