In-tube convective heat transfer characteristics of CO2 mixtures in a pipeline

In the Carbon Capture, Transportation & Storage (CCS) process, CO2 is captured with impurities such as N-2, CH4 and Ar and is transported under a supercritical state. In this study, the characteristics of in tube convective heat transfer of CO2 mixtures such as CO2 + N-2, CO2 + CH4 and CO2 + Ar were experimentally investigated under the land transportation conditions of the CCS process. The test tube was made of a cooper tube buried in a PVC (Polyvinyl Chloride) pipe which was compactly filled with sand, which simulated the land CO2 transportation. Mass flux was changed by 200, 400 and 600 kg m(-2) s(-1), and operational pressures were 80, 90, and 100 bar. Operational temperatures ranged from 25 to 55 degrees C. The heat transfer coefficient of the CO2 mixtures dominantly followed the trends of pure CO2; however, they were decided by the type and quantity of the impurity. When the CO2 mole fraction was changed from 1.00 to 0.95, the maximum heat transfer coefficient at the pseudo-critical temperature of CO2 + N-2 and CO2 + CH4 decreased by 4389 W.m(-2) K-1 and 2770 W.m(-2) K-1, respectively. As the mass flux increased, the heat transfer coefficient increased in all of the CO2 mixtures. (C) 2018 Elsevier Ltd. All rights reserved.