Properties that affect the behaviour and the persistence of an oil spilled at sea.

The main physical properties that affect the behaviour and persistence of oil spilled at sea is,

Specific Gravity

Distillation Characteristics

Vapour Pressure

Viscosity

Pour Point…..all these depends on chemical composition, such as the proportion of volatile component and the content of asphaltenes, resins and waxes.

i.?????????????Specific Gravity: Specific gravity of an oil is its density in relation to pure water. American Petroleum Institute (API) is commonly used to describe the specific gravity of crude oil and petroleum products.

ii.???????????Distillation characteristics: It describes its volatility. It also expresses the proportion of the parent oil that distil within given temperature ranges.

iii.??????????Vapour pressure: It is indication of volatility of an oil. Vapour pressure greater than 3kPa (23mm of Hg) is the criteria for evaporation to occur under most conditions.

iv.??????????Viscosity: Resistance to flow.

Viscosity is inversely proportional to temperature.

v.???????????Pour point: The temperature below which oil no longer flows. It is a function of wax and asphaltene content.

On cooling, an oil will reach a temperature, termed cloud point (point where wax converts to crystals), further cooling the pour point is reached (point where liquid converts to semi-solid).

Understanding basic properties can helps determine the fate of oil spill.