1.1 Conceptual Framework
Vaporization Losses are encountered through vapors generated by heat gained through the shell, bottom and roof vessels. The total heat input is the algebraic sum of the three modes of heat transfer which are radiant, conductive and convective heat transfer. This type of loss is especially prevalent where light HC liquids are stored in full pressure or refrigerated storage. They are less prevalent but still quite common in crude oil and finished product tanks. This vapor can be recovered by using the vapor recovery systems.
Displacement losses are losses made up of combined loss from filling and emptying is considered a working loss or displacement loss. As liquid level increase, the pressure inside the vessel exceeds the relief pressure and vapors are then expelled from the vessel. During emptying of liquids product evaporative loss occurs, and air is drawn into the tank during liquid removal, it become saturated with organic vapors and expands, thereby exceeding the vapor space capacity.