blog

Welding the LNG Tanks

LNG Tanks are structures designed to store natural gas in a liquid state at atmospheric pressure. Depending on its chemical composition, the liquid state at atmospheric pressure is achieved by cooling the natural gas to a temperature below -160°C. Flat bottom cylindrical tanks can be from simple containment to full containment tanks. The outermost is usually a concrete cylinder with a framework of cryogenic bars and pre-stressed with circular and vertical steel cables. The full containment tanks are typically made up of 4 containers.

Petroleum tanks used to store crude oil, aviation fuel, gasoline, diesel and other products above and below ground. Leaking tanks may create significant environmental damage and jeopardize safety. Soil and water contamination can be tremendous and be undetected for years. Different methods have been developed and applied during the recent decades for non-destructive evaluation of metal and fiber-reinforced plastics (FRP) structures. Among these methods, acoustic emission technology is unique as it not only detects flaws but also is used for on-line, real-time monitoring of structural integrity without interruption of operation, cleaning, or product evacuation.

The oil and gas industry experienced some major challenges in 2020. With the sudden reduction in fuel consumption, there was a substantial global surplus of crude oil. This unique situation has seen storage facilities reach maximum capacity and even crude tankers being used to store unwanted product. Retired storage facilities are being targeted for reinstatement, and operators are considering tank construction to increase capacity. With increased storage requirements and potential inspection deferrals, there is also an increased requirement to perform in-service tank inspection to assess critical components within the asset. This article will do a complete NDT techniques revision that can be applied to the recommissioning tanks.

The oil and gas industry experienced some major challenges in 2020. With the sudden reduction in fuel consumption, there was a substantial global surplus of crude oil. This unique situation has seen storage facilities reach maximum capacity and even crude tankers being used to store unwanted product. Retired storage facilities are being targeted for reinstatement, and operators are considering tank construction to increase capacity. With increased storage requirements and potential inspection deferrals, there is also an increased requirement to perform in-service tank inspection to assess critical components within the asset. This article will do a complete NDT techniques revision that can be applied to the recommissioning tanks.

The austenitic and nickel-based metal alloys used for welding, as well as other coarse-grained anisotropic materials, affect the propagation of ultrasound. This results in beam distortion or scattering, mode conversions, and significantly increased attenuation resulting in a poor signal-to-noise ratio (SNR), compared to shear wave inspections on low-alloy carbon steels.

Phased-array technique has been used for years and approved in many NDE applications thanks to its flexibility and the great improvement in productivity. They can display ultrasonic data as sectorial or linear images (S-scan or E-scan) allowing an inspector to see instantly a complete zone of the component and thus interpret data more easily. These images are obtained by applying time delays to each element of an array probe. But now, recent developments in Non-Destructive Testing (NDT) technology have resulted in new techniques as Total Focusing Method (TFM). Let us summary the key difference between Phased Array Ultrasonic Testing (PAUT) and Total Focusing Method (TFM): Is one better than the other?

If you belong to the world of Non-Destructive Testing and more specifically, in those techniques related to Ultrasound, most likely, you have recently heard about these 2 inseparable brothers! FULL MATRIX CAPTURE (FMC) and the TOTAL FOCUSING METHOD, let see: What are both techniques and Why are inseparables? In this article let us talk about Total Focusing Method (TFM)

If you belong to the world of Non-Destructive Testing and more specifically, in those techniques related to Ultrasound, most likely, you have recently heard about these 2 inseparable brothers! FULL MATRIX CAPTURE (FMC) and the TOTAL FOCUSING METHOD, let see: What are both techniques and Why are inseparables? In this article let’s talk about FULL MATRIX CAPTURE (FMC)

In the past article, we talked about Guided Waves as a method to detect Corrosion Under Insulation (known by its acronym in English, CUI) in fact, the GW’s were born to inspect CUI. Now in this paper we are exploring the Digital Radiography as an alternative method to find this kind of phenomenon in pipes or vessels.

In the past article about CUI, we defined Corrosion Under Insulation (known by its acronym in English, CUI) as a phenomenon that normally affects pipes and pressure equipment made of carbon steel, as a result of the entry or condensation of water under the thermal insulation. Within this category of corrosion can also be included the corrosion generated –for the same cause– under the lagging (CUF, corrosion under fireproofing) of pipes and pressure equipment.