Vapor Losses

Vapors emitted from the vents and/or relief valves of a storage tank are generated in two ways:  they are forced out of the tank during filling operations and  they are generated by vaporization of the liquid stored in the tank. Technical Data used in the field explained in petroleum courses in Rawalpindi. The total vapor produced in these two instances is the volume that would be available for recovery.

Filling Losses

Vapors that are forced out of the tank are generally called “filling losses.” A storage tank generally is not pumped completely dry when emptied. The vapor above the remaining liquid in the tank will expand to fill the void space at the vapor pressure of the liquid stored in the tank at storage temperature. As the tank is filled, the vapors are compressed into a smaller void space until the set pressure on the vent/relief system is reached. There are also some filling losses that are associated with the expansion of the liquid entering the tank. provides a graphical approach to estimating the filling losses as a percentage of the liquid being pumped into the tank. Some more details of petroleum courses in rawalpindi are as under.

Vaporization Losses

This type of loss is characterized as the vapors generated by heat gain through the shell, bottom. and roof. The total heat input is the sum of the radiant, conductive, and convective energy forces. This type of loss is especially prevalent where light hydrocarbon liquids arc stored in full-pressure or refrigerated storage. This is less prevalent but still quite common in crude oil and finished product storage tanks. These vapors may be recovered by the use of a vapor-recovery system.

Crude oils and condensates are composed of many different paraffin hydrocarbons. Propane is the lightest hydrocarbon found in any measureable amount and the hydrocarbon with the greatest tendency to evaporate or vaporize from the liquid stored. When propane and other hydrocarbons pass into the vapor phase by vaporization, the volume of the liquid stored is decreased. and because these lighter hydrocarbons arc not now present in their initial amounts, the API gravity of the crude is decreased. There is a definite relationship between API gravity lost and volume lost. depending on the character of the crude. TSK Training for Skills and Knowledge is the best institute in Rawalpindi Islamabad for Pakistani Students who wants to join petroleum courses in Islamabad.