Investigations on vapor cloud explosion hazards and critical safe reserves of LPG tanks

To clarify vapor cloud explosion hazards in process industries and strengthen emergency treatment measures, a full-scale liquefied petroleum gas (LPG) tank model was established using computational fluid dynamics (CFD). Also, gas dispersion behavior and explosion hazards under different leakage characteristics were investigated and LPG safe reserves reasonably predicted. The results showed that heavy gas expansion near the ground mainly moved along gaps between structural congestions, while continuous large-scale congestion had significant enhancement effects on gas expansion and concentration accumulation. When an LPG cloud with nonuniform concentration ignited, the turbulent flame impacted the diluted explosive cloud at high speed, resulting in more serious consequences. When LPG leakage exceeded 300 s and the aperture greater than 10 mm, the hazard zone (P_c > 2 kPa) sharply increased and therefore considered to be the key factor in controlling explosion hazards. The LPG safe reserve varied little under low protection distance (R_p) and critical overpressure (P_c), but increased exponentially when R_p and P_c exceeded 200 m and 20 kPa, respectively. The present research conclusions provided a theoretical reference for emergency disposal, disaster assessment, and reserve safety design of LPG leakage and explosion accidents.