STRESS EVALUATION IN CRYOGENIC PIPING: ENGINEERING SOLUTIONS AT -90°C

A major LNG production facility in the Arctic required a redesign of critical piping near one of its main compressors, where carbon steel was being replaced with stainless steel. Belman Design was brought in for a fast-paced, collaborative reconfiguration effort based on a revised isometric layout provided by the client.

CLIENT ISSUE
The site faced extreme environmental conditions, with temperatures dropping to -50°C and permafrost present most of the year. The piping system operated under demanding parameters with temperatures ranging from -90°C to +90°C, pressures up to 49.5 barg, and tight spatial constraints within an existing ethane system. Key issues included excessive nozzle loads, complex routing geometry and multiple component clashes.

The redesign had to respect strict space limitations and avoid major physical modifications to the existing structure. Additional complications included limited access to accurate 3D models early in the process, mechanical interferences and the need to account for rapid thermal shifts that could significantly affect pressure behaviour and cycle loading.

BELMAN DESIGN SOLUTION

Expert evaluation of pipe stresses in severe cold conditions

Belman Design was asked to evaluate the feasibility of the original concept and develop a robust alternative. Initial efforts focused on improving load distribution without altering the general piping layout. Through detailed stress analysis in ROHR2, Belman Design identified the need to modify support positions, adjust fixed points and implement new Expansion Joint configurations. The team proposed Pressure Balanced Expansion Joints tailored to each section, striking a balance between performance and space availability. As part of this work, critical nozzle loads were reduced to acceptable levels, with deviations clearly justified and accepted by the client based on applicable design codes.

Adjusted pipe layout were suggested as 3D model revealed conflicts

The 3D model later provided by the client revealed additional spatial conflicts. Belman Design re-evaluated the configurations to avoid interference with platforms, buildings and nearby lines, suggesting adjusted layouts using more compact and applicationspecific units such as Corner Relief and Tied Expansion Joints. A final configuration combined Gimbal Expansion Joints inside the building with Pressure Balanced (Finger Type) Expansion Joints outside, tailored for flexibility and minimal installation footprint.

Throughout, Belman Design worked closely with the client and their engineering teams to verify compressor loads, establish anchor point reactions and supply calculation data for approval by the regulatory authorities. The designs accounted for installation temperatures, operating regimes, cycle life under fluctuating pressure and integration with the surrounding structure.