Experiment 7: Density, Specific Gravity, and API of Liquid Petroleum Products

1. Measure the specific gravity (relative density) and API gravity of petroleum products using hydrometers

2. Mesure the density of petroleum products using a digital density meter

3. Perform corrections for the observed specific and API gravities

Objetives of the experiment

Specific gravity, API gravity, and density

Expressions of the mass-to-volume relationship of a product

Density

Mass of liquid per unit volume

15^o C

Temperature used to determine density in the experiment

Relative density/specific gravity

Ratio of the mass of a given volume of liquid to a mass of an equal volume of pure water at the same temperature

API gravity

Special function of relative density

Equation of API gravity

10

API gravity of water

Decrease in its mass per unit volume

Result of petroleum product expanding when heated

Refinery operations

Operation where gravity is useful

Type of petroleum products

What gravity helps to indentify

Petroleum and market value

What API gravity helps to identify

Light crude oils

Crude oils with API gravities greated than 31.1^o classify as

Heavy crude oils

Crude oils with API gravities less than 22.3^o classify as

Heat of combustion of diesel, burner, and aviation fuels

What density helps estimate

American Society for Testing and Materials

ASTM stands for

Using ASTM D1298 to determine the density, relative density, and API gravity using a glass hydrometer

First method of the experiment

Using ASTM D4052 to measure the density of petroleum products at 15^o C using a digital density meter

Second method of the experiment

Measuring the change in oscillation frequency of the sample tube caused by the change of mass in the tube

How the density is determined in the second method of the experiment

1. Gasoline

2. Motor oil

3. Diesel fuel

Samples used in the experiment

1. Hydrometer

2. Density meter

Equipment used in the experiment