Numerical analysis of temperature fields around the buried arctic gas pipe-line in permafrost regions

• Main Authors: Li Xinze, Jin Huijun, Wei Yanjing, Wen Zhi, Li Yan, Li Xinyu
• Format: Article
• Language: English
• Published: VINCA Institute of Nuclear Sciences 2021-01-01
• Series: Thermal Science
• Subjects: natural gas pipe-line; coupled thermal-hydraulic modeling; pipe-soil heat exchange; numerical simulation; permafrost; chilled transporting processes
• Online Access: http://www.doiserbia.nb.rs/img/doi/0354-9836/2021/0354-98362000248L.pdf
• ISSN: 0354-9836; 2334-7163

Based on one planned arctic natural gas pipe-line engineering which will cross continuous, discontinuous, sporadic and non-permafrost areas from north to south, with different pipe-line temperatures set, a thermal model of the interac-tion between pipe-line and permafrost is established to investigate the influence of pipe-lines on the freezing and thawing of frozen soil around pipe-line and thermal stability of permafrost. The results show that different pipe-line temperatures influ¬ence the permafrost table greatly. Especially in discontinuous permafrost areas the permafrost table is influenced in both positive temperature and negative tempera¬ture. The warm gas pipe-line of 5℃ could decrease the value of permafrost table about 1 to 3 times pipe diameter and aggravate the degradation of permafrost around pipe-line; –1℃ and –5℃ chilled gas pipe-line can effectively improve the permafrost table and maintain the temperature stability of frozen soil, but the temperature of soils below pipe-line of –5℃ decreases obviously, which may lead to frost heave hazards. In terms of thermal stability around pipe-line, it is advised that transporting temperature of –1℃ is adopted in continuous permafrost area; in discontinuous permafrost area pipe-line could operate above freezing in the summer months with the station discharge temperature trending the ambient air temperature, but the discharge temperature must be maintained as –1℃ through¬out the winter months; in seasonal freezing soil area chilled pipe-line may cause frost heave, therefore, pipe-line should run in positive temperature without extra temperature cooling control.