Numerical study of the effect of heat transfer on solid phase formation during decompression of CO₂ in pipelines

Department of Chemical Engineering, University College London, WC1E 7JE, London, UK

^* Corresponding author: h.mahgerefteh@ucl.ac.uk

Abstract

CO₂ solid phase formation accompanying rapid decompression of high-pressure CO₂ pipelines may lead to blockage of the flow and safety valves, presenting significant hazard for safe operation of the high-pressure CO₂ storage and transportation facilities. In this study, a homogeneous equilibrium flow model, accounting for conjugate heat transfer between the flow and the pipe wall, is applied to study the CO₂ solid formation in a 50 mm internal diameter and 37 m long pipe for various initial thermodynamic states of CO₂ fluid and wide range of discharge orifice diameters. The results show that the rate of CO₂ solid formation in the pipe is limited by heat transfer at the pipe wall. The predicted amounts of solid CO₂ are discussed in the context of venting of CO₂ pipelines.