Oil fuel,in all of its usable forms,is a refined product,unlike coal and natural gas which can often be burned in their natural condition.

Oil Fuel

is a type of fuel derived from the refinement of crude oil used primarily for heating, transportation, and generating electricity.

Refined Product

A substance that has been processed and purified from its raw state to enhance its utility or value.

Coal

A combustible black or brownish-black sedimentary rock made largely of carbon and hydrocarbons, used as a fossil fuel for producing energy.