Thermal attenuation pattern in long-distance CO2 transport pipeline: Implications for careful heat management

Abstract The inherent thermal dissipation during long-distance CO2 pipeline transport poses significant challenges to operational safety and efficiency, particularly regarding hydrate formation and pipeline blockages. Careful thermal management is essential to deal with these challenges, which requires deep understanding of the thermal dissipation characteristics. In this study, we established a thermal dissipation model for long-distance gaseous CO2 pipeline transport to understand the thermal attenuation patterns under different thermal management strategies, and quantitatively evaluate the thermal dissipation intensity along the pipeline. Numerical results show that CO2 temperature decay generally follows an exponential relation with distance. For a common situation with the inlet temperature of 295 K, the ambient temperature of 275 K, and pipeline length of 30 km, the distance for an 80% decay in gas temperature is about 10 km. Regarding extending the distance without hydrate formation risk, intermediate heating after the temperature decay reaches 80% provides more effective thermal compensation than raising the inlet temperature of CO2. Increasing the inlet temperature by 10 K only extends the distance with a temperature above hydrate phase equilibrium temperature by 42%, but intermediate heating increases the distance by 89%. Passive thermal protection also shows substantial mitigation effects. Increasing the thickness of the insulation layer from 0 to 0.025 m extends the distance by 21 km, while optimizing the insulation thermal conductivity from 0.15 to 0.05 W/(m·K) extends this distance by 17 km. Findings enhance understanding of thermal dissipation in long-distance CO2 pipelines.