Flammability Limits Study ofVapour Mixtures above Crude Oil at Low Temperatures

Study of fire and explosion is very important mainly in oil and gas industries due to
the severity of fire and explosion incidents. Fire and explosion could cause property
damage and loss of lives. In this work, investigation had been carried out on the
flammability of crude oil at low temperatures 35°C, 40°C and 50°C. Hydrocarbon
components derived from refinery storage was assessed. The oil-liquid phase was
analyzed using Headspace-Gas Chromatography (HS-GC) and Gas Chromatography
Mass Spectrometry (GC-MS) to examine the composition of the sample.
Hydrocarbon compounds ranging from C6 to C9 were detected. Lower Flammability
Limits (LFLs) and Upper Flammability Limits (UFLs) for individual components
were calculated at each temperature using stoichiometric concentration method
proposed by Zabetakis et. al. Flammability limits of the mixture, LFLmiX and UFLn^
were calculated using the Le Chatelier equation. Limiting Oxygen Concentration
(LOCs) for each temperature are calculated using Hansen and Crowl method, while
the estimation ofLOC for the mixtures (LOC„ux) is calculated using Zlowchower and
Green method. Flammability diagramwas constructed which is used to determinethe
flammability of the mixture at respective temperature. It is found that as the
temperature increases, the flammability range of vapours above crude oil increases
too. The findings of this studymay assist in minimizing fire hazards associated with
presence ofhydrocarbon vapours.