Experimental investigation of the flow characteristics of jettisoning in a CO2 carrier

Abstract

This experimental study was performed to investigate the flow characteristics in the jettisoning flow line of a liquid CO2 carrier. When a pressurized liquid CO2 container loses mechanical integrity, possibly by material or mechanical defects, the liquid inventory should be drained out rapidly for safety reasons using the so-called jettisoning process. In the course of jettisoning, the liquid CO2 undergoes two phase change stages, from liquid to liquid + vapor and from liquid + vapor to solid +vapor. Consequently, the jettisoning release rate is affected by the characteristics of these-phase changes. In this study, liquid CO2 was discharged through a small tube, representing a jettisoning flow line. The temperature and pressure were measured along the tube, and the locations of the phase changes were inferred from the measured data. The experimental results showed that active nucleation occurred near the tube tip and that the phase change into solid and vapor occurred just after leaving the pipe, irrespective of the tube length in this study.