Thermal and mechanical response of frozen soils and buried pipeline armed with thermosyphons and insulation layer

• Published in: Heat and mass transfer Vol. 59; no. 9; pp. 1591 - 1599
• Main Authors: Zhou, Jiawei, Liang, Zheng, Zhang, Liang, Zheng, Ting, Zhang, Siyang
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.09.2023; Springer Nature B.V
• Subjects: Buried pipes; Degradation; Engineering; Engineering Thermodynamics; Frozen ground; Heat and Mass Transfer; Industrial Chemistry/Chemical Engineering; Insulation; Mechanical analysis; Original Article; Permafrost; Petroleum pipelines; Pipeline safety; Pipelines; Soil mechanics; Thermodynamics; Thermosyphons; Yield stress
• ISSN: 0947-7411; 1432-1181
• DOI: 10.1007/s00231-023-03352-0

In permafrost regions, permafrost degradation negatively jeopardizes the security of infrastructures, in which large pipeline deformation will happen owing to settlement disaster. Under the scenarios of climate warming and positive oil temperature, how to effectively alleviate permafrost degradation is a critical issue. Numerical evaluation is performed on the influences of the protective measures, which include insulation layer, two-phase closed thermosyphon (TPCT), and combined measures based on the thermo-mechanical coupled model. The numerical results show that most of the heat released from the warm-oil pipeline to soil is isolated by insulation layer, and the expected insulation thickness is 8 cm. On the other hand, TPCT can effectively cool underlying permafrost inhibiting the thaw bulb from growing over time by air-TPCT-soil heat transfer. The combination of insulation layer and TPCT has significantly reduced the pipe stress by more than 60% within 30 years, in which the maximum stress of pipeline is consistently lower than the yield stress. Consequently, the combined measure should be considered for application to ensure pipeline safety in permafrost.