Before seeing how petroleum fuels impart thrust, let us first see how they are manufactured:
Refining crude oil produces petroleum fuels. Crude oil simply means unprocessed oil. Crude oil is a fossil fuel as it has been formed in the earth's crust by decaying of the fossils of plants and animals. These fossils are subjected to high temperature and pressure for millions of years to form crude oil.
The oil is made up of mixture of complex hydrocarbons (compounds containing mainly carbon and hydrogen).
Crude oil consists of large number of components mixed together. Therefore to obtain kerosene which is used as a propellant various components of crude oil will have to be separated. To separate the components of crude oil 2 processes have been employed
In this process various components of the crude oil having different weight, sizes and boiling temperatures are heated. The vapors formed enter a column called fractionating column. When a substance in the vapor reaches a height where the temperature of the column is equal to that substance's boiling point, it will condense to form a liquid. Thus this process separates all the components
They can also be employed to separate the components of crude oil. These include breaking of large hydrocarbons into smaller hydrocarbons, combining small hydrocarbons to make larger one and rearranging to obtain desired hydrocarbons.
After obtaining kerosene from one of the above processes it is used in combination with liquid oxygen as the oxidizer. Kerosene obtained is referred to as RP-1 (highly refined petroleum). RP-1 delivers a specific impulse considerably less than cryogenic fuels. (See cryogenic fuels).
Kerosene was used to power the first-stages of the Saturn 1B and Saturn V rockets.
The next type of liquid propellant is Cryogenic propellant