On-stream, real-time, asset integrity for the digital refinery
In the oil & gas, refining and power generation industries globally, it is estimated that 25% of the costs involved in outages could be avoided by replacing conventional risk-based inspection strategies during planned shutdowns, with in-service inspection and monitoring. On-stream, non-intrusive, ultrasonic corrosion monitoring and asset integrity transducers are becoming increasingly popular, to enable refiners to enhance process unit productivity, optimise shutdown and maintenance planning, whilst not compromising on safety.
A range of high-temperature ultrasonic inspection tools for operation on robotic crawlers for on-stream corrosion mapping, and automated wall thickness monitoring solutions have come to the market, enabling up-to-date, robust and reliable corrosion/erosion data to be autonomously collected and trended to give insights to better plan or defer maintenance and improve asset or process intelligence.
Like all emerging technologies, a thorough understanding of the strengths and also shortcomings of these systems is required to deploy them onto sites in such a way that they provide the required data, in the correct form, and at the required location(s).
For example, recent updates to recommended practices for high-temperature sulfidic corrosion require 100% inspection of components at risk and monitoring where accelerated corrosion is identified.
Sulfidation corrosion of steel downstream refining assets is a ubiquitous damage mechanism occurring in crudes when heated above 230°C which is difficult to predict, costly to repair and can cause catastrophic ruptures rather an leaks, in piping, tubing and pressure vessels.
Presented here is a review of the current and emerging technologies for ultrasonic inspection and monitoring, used to assess corrosion such as sulfidation, in high-temperature assets (up to 550°C). It covers all aspects, from the development and challenges associated with the selection of piezoelectric elements, transducer design and couplings, to the availability and application of commercial systems in the field.
Selecting what data to collect, who will benefit from it, how it will be stored, and the value of increased and improved data will be explained. The use of such technologies within the constraints of NDT regulations and standards, including calibration and temperature compensation will also be covered.
The location and environment of UT data collection is considered, including hazardous and potentially explosive environments, working at height /rope access and the integrity of insulation or cladding.
Finally, a case study, highlighting a field example, is presented and explores the key factors which must be considered when selecting an ultrasonic corrosion monitoring system.
This review will be of interest to all inspectors, integrity and corrosion engineers and plant managers who wish to improve their understanding of automated ultrasonic corrosion monitoring and apply it to their processes and plants.
The development of these high temperature resilient platforms also allows for extended applications to assess other damage mechanisms such as weld defects and material flaws and cracks.
