In Nigeria, the majority of the oil/gas/liquids pipelines are 30 to 50 years old. Most of the pipes were laid on the surface. But these pipelines have become old, corroded and less effective. They fail due to corrosion induced leaks ( resulting from lack of pipeline integrity survey and inadequate corrosion monitoring program design ) as well as vandalism.
A close-interval potential (CIP) data survey on ~154 km of Crude Oil/Gas pipeline networks. This aim was to generate corrosion data to determine weak sections of the pipelines/flowlines and, to ascertain the effectiveness of the CP system and integrity of the Crude Oil/Gas pipeline networks. The pipeline networks were found safe for continued operation under its present condition.
Service life of any weapon system depends upon factors that impart long-term durability and robustness to its structure and subsystems, while sustaining its functional properties. The paper describes basic principles and guidelines on corrosion control and rules that could be easily followed to ascertain some specified service life and reduce total ownership costs.
In seawater, higher strength nickel-copper alloys are used as alternatives to copper alloys. These can be susceptible to chloride stress corrosion cracking and hydrogen embrittlement in conditions where cathodic protection is utilized. Copper-Nickel-Tin alloys (CuNiSn) show low corrosion rates in the free and coupled conditions. Resistance to hydrogen embrittlement is demonstrated.
Traditionally, closed system treatment programs have involved adding corrosion inhibitor and
periodically testing for the residual. To be effective, these treatment programs must also
include cleaning. This paper will discuss the various aspects that should be evaluated as part of a closed system treatment program.
Currently, a number of fracture mechanics-based methods are available for crack assessment. In this paper, a critical review is given to failure assessment diagram (FAD), in particular the API 579-2000 fracture mechanics assessment method for crack-like flaws. Illustrations, arranged by applicability to field examples, demonstrate the approach.
UNS N04400 cladding on steel valves can corrode during marine service. The uniform corrosion rate of an EN coating in artificial seawater was measured by electrochemical impedance spectroscopy and was found to be less than that for N04400. The main conclusion is that an EN coating could be a viable solution to repair N04400-clad valves in-situ.
Under-deposit corrosion is a common mode of failure in boiler tubes. Mechanisms include phosphate attack, caustic gouging, hydrogen damage, and wall thinning due to metal loss. Many aspects of these mechanisms and their mitigation are well-understood, while certain specific details remain uncertain or subject to controversy.