A numerical study on the non‐isothermal flow characteristics and hydrate risk of CO₂ in buried transmission pipelines under the gas‐phase transportation mode

With the development and progress of carbon dioxide (CO 2 ) capture and storage technology, the study of the flow assurance of CO 2 in transmission pipelines needs to be further deepened. In this study, aiming at the gas‐phase transportation mode of CO 2 , first, a new prediction model of temperature, pressure as well as hydrate formation risk in buried CO 2 transmission pipelines is established. Second, the model solving methods of differential discretization and piecewise iteration are introduced in detail. Third, model validation and sensitivity analysis of typical transmission parameters are performed. The results show that: (a) there is good agreement between the model prediction results and software simulation results. (b) The subcooling and the length of the hydrate formation region increase with the increase in the transmission rate. Appropriate increase in the CO 2 transmission rate can reduce the risk of hydrate formation in CO 2 transmission pipelines. (c) The subcooling and the length of the hydrate formation region decrease as the transmission temperature increases. In order to prevent hydrate risk in the CO 2 transmission process, low transmission temperatures should be avoided. (d) The subcooling and the length of the hydrate‐formation area increase first and then decrease as the transmission pressure increases. Appropriate increase in CO 2 transmission pressure is conducive to avoiding hydrate formation risk. This study provides basic theoretical guidance for optimizing transmission parameters and risk assessment of hydrate formation in CO 2 transmission pipelines.