There are numerous hazards associated with chemical processing, especially with highly inflammable substances like Liquefied Petroleum Gas (LPG). The process safety engineer plays a pivotal role in identifying the associated hazards, areas of influence and their mathematical representation to ensure that the risks involved in these hazards can be reduced to acceptable levels through the application of engineering principles and proven engineering practice. In modern hydrocarbon plants, LPG is widely stored in various vessels. The fire and explosion hazards of these objects are extremely high. This has been confirmed by a series of accidents involving fires and explosions that have taken place around the world. In the present paper, the fire and explosion hazards associated with the LPG are described with the most appropriate mathematical models. Safe storage options which avoid the chances of these explosion hazards are also reviewed.

Liquefied Petroleum Gas (LPG) is the generic name of the predominant mixture of propane and butane having both saturated and unsaturated hydrocarbons. Propane and butane have the special property of changing into liquid state at atmospheric temperature if moderately compressed, and reverting to gaseous state when the pressure is sufficiently reduced. This property is taken advantage of to transport and store these products in liquid state since they are roughly 250 times denser than in gaseous state.

It has been observed that the quality of LPG dealt in India varies a lot depending on the source of supply and number of constituents, which mainly consist of one or more of the following hydrocarbons (HPCL, 2006): Propane (C₃H₈), Propylene (C₃H₆), n-butane (C₄H₁₀), Isobutane (C₄H₁₀), and Butylene (C₄H₈). However, small quantities of one or more of the following hydrocarbons may also be present: Ethane (C₂H₆), Ethylene (C₂H₄), Pentane (C₅H₁₂) and Pentene (C₅H₁₀).

Currently LPG is being widely used for various applications like cooking, Industrial applications for heating, heat treatment, metal cutting, solvent, aerosol applications, automotive fuel, etc.

The event that occurs after the release of LPG depends on the nature and, particularly the position of the failure on the vessel, the rate of release, rate of admixture with air, proximity of sources of ignition, etc. (Crocker and Napier, 1986). The resulting event may be one of the fires (jet fire, flash fire, pool fire and fireball) or an explosion (Boiling Liquid Expanding Vapor Explosion (BLEVE) or Unconfined Vapour Cloud Explosion (UVCE)). The evolution of the effects after the release of LPG is presented in Figure 1.

Chemical Engineering Journal, Liquefied Petroleum Gas, Mathematical Models, Industrial Applications, Pool Fires, Chemical Process Industries, Thermal Radiation, Quantitative Risk Analysis, Combustion Stoichiometry, Industrial Risk Insurers, Surface Emitted Flux.