Classification and characteristics of supercritical carbon dioxide leakage from a vessel

Abstract

Accidental leakage is one of the major safety issues of carbon capture, utilization and storage (CCUS) projects. Fully understanding SCO2 leakage characteristics is very important for safety system design and leakage detection. In this paper, supercritical carbon dioxide decompression experiments were studied based on a set of 50.0 L pressurized vessel experimental apparatus. The decompression characteristics and influence of orifice sizes, initial temperature and initial pressure were analyzed. The results show that the supercritical CO2 vessel decompression undergoes two different decompression processes. This is mainly because of drastic changes in physical properties near critical point and pseudo-critical point. Supercritical region is divided into gas-like phase and liquid-like phase according to initial temperature higher or lower than pseudo critical temperature. Besides, low initial temperature and large orifice size resulted in great temperature drop in the vessel. In each decompression processes, decompression time is mainly related to leakage diameters and initial pressure. The experiments results show lower temperature will not damage material. Experiment results are of great significance for understanding process of accident and model development.