Project Description
Managing LNG on-site is tricky due to the low temperatures required (~-150°C), therefore stainless steel is often used due to its resistance to becoming brittle at these temperatures. Typically, pipelines and supporting structures (pipe shoes) are made up of stainless steel. However, as stainless steel is costly, the underlying support beams are made from mild steel. Currently, there is an insulating pad between the pipe shoe and steel support structure as there is a requirement for the temperature of the mild steel to not drop below 0°C during a blow-down event.
However, due to the age of the plant, these insulation blocks are starting to degrade and need replacing. This project looked at whether these insulation pads are actually necessary. Ten tests were carried out using a simulated blow-down event at different atmospheric conditions. A short section of pipe was filled with liquid nitrogen, which was maintained at greater than 50% capacity. Seventeen temperature sensors and 1 humidity sensor were used to measure the temperature of the pipe, shoe and support structure. The plain steel support took long time to reach 0°C even under unrealistic atmospheric conditions. In more realistic cases, 0°C was never reached. Therefore the support structure for these pipeworks can forgo the use of Permali insulation at a saving of $3 million.
Woodside contact: Rory O’Keeffe, Technology & Innovation Manager