Boiling liquid expanding vapour explosions (BLEVEs): A brief review

• Published in: Journal of loss prevention in the process industries Vol. 32; pp. 30 - 43
• Main Author: Eckhoff, Rolf K.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.11.2014; Elsevier Science Ltd
• Subjects: Accidental explosions; BLEVE; Evaporation; Explosions; Fireballs; Fires; Flammability; Fluids; Gases; Liquids; Pressure; Process safety; Superheat limit temperature; Toxicity; Vapour; Vessel failure; Vessels; Superheat limit temperature; Process safety; Accidental explosions; Vessel failure; BLEVE
• ISSN: 0950-4230; 1873-3352
• DOI: 10.1016/j.jlp.2014.06.008

BLEVEs remain a complex multi-faced phenomenon. The point of departure of the paper is the extensive review by Abbasi and Abbasi (2007), and the paper starts with presenting some deviating definitions and suggested characteristics of BLEVEs. Then a step-by-step description of the chain of events in typical BLEVEs follows. In most cases the first step will be that a vessel containing a gas that has been liquefied by pressurization (PLG) gets accidentally exposed to heat (most often a fire). The next step is that the vessel suddenly fails due to the increased internal vapour pressure and the weakening of the vessel material. The resulting very sudden depressurization of the hot liquid gives rise to intense, often volumetric, evaporation. The central role of the superheat limit temperature (SLT) of the liquid in the evaporation process is discussed. The very rapid evaporation in turn gives rise to powerful blast wave emission. If the evaporated liquid is combustible and gets ignited, a huge fireball will most often be generated. Properties and effects of fireballs from BLEVEs are discussed. The shattering of the initial vessel may cause propelling of high-speed missiles, which when hitting other PLG vessels may give rise to secondary BLEVEs. The remaining part of the combustible liquid from a BLEVEed vessel that has not evaporated will, when ignited, give rise to pool fires. Emission of toxic gases/vapours requires special actions. However, BLEVEs can also occur with non-toxic gases, and even in the absence of an initial fire. The induction time preceding a BLEVE is an important parameter, e.g. for the time available for rescue operations. Long-duration BLEVEs require special concerns. A part of the paper is devoted to various categories of BLEVE case histories. Available means for preventing process situations that can lead to BLEVEs are then discussed. If PLG-vessels get engulfed in fire measures for preventing catastrophic vessel failure may be activated. Finally measures for mitigating the consequences if BLEVEs do occur in spite of taking preventive measures are discussed. •The superheat limit temperature of the liquid plays a key role in BLEVE development.•Strong pressure waves result from BLEVEs.•Huge fireballs can result from BLEVEs with flammable liquids.•Ejection of missiles from shattered vessels is central in BLEVE escalation.•Measures for preventing BLEVEs and minimizing consequences are available.