Theoretical And Experimental Study On Solid CO₂BLEVE Under Thermal Attack

Emission of carbon dioxide is considered to be an important reason for global warming.Currently, as a promising method to CO2mitigation, carbon capture and storage (CCS) hasbeen widely used in many countries, and it is also applied to enhance oil recovery (EOR).Both CCS and CCS-EOR require handling large volumes of high pressure CO2, Whichassociated with a severe hazard, i.e. the Boiling Liquid Expanding Vapor Explosion(BLEVE) due to the failure of the vessel.The current study on BLEVE is mainly forliquefied petroleum gas, liquefied natural gas, superheated water and other substances,however, the mechanism of CO2remains unclear, with very limited experimental workperformed.In this work, a new theoretical approach has been proposed to calculate the superheatlimit temperature (SLT) of CO2. The SLT has provided a framework with which thelikelihood as well as the severity of a possible BLEVE can be predicted. With thecharacteristics of discontinuity and mutability, CO2BLEVE procedure under thermal attackcan be qualitatively descripted with a catastrophe model established by the van der Waalsequations, which made a good explanation of the mutation process of CO2phase transition.Experimental work on CO2BLEVE studies has been performed in laboratory. It isfound that there is thermal stratification in the liquid zone, and from top to bottom, is thegas phase, gas-liquid phase, liquid phase. Besides, both the amount of repressurization andthe rate of repressurization are found to be proportional to the amount of depressurizationand the rate of depressurization. The time for repressurization is typically an order ofmagnitude larger than the time for the pressure drop. It is also indicated that a BLEVE canoccur below the SLT and may not occur beyond the SLT, but the blast effect may be muchhigher with a higher degree of superheat degree.