Feedstock

Fractions also provide feedstock for the petrochemical industry: starting materials that can be processed into useful substances. These include solvents, lubricants, polymers and detergents. Carbon atoms can bond to one another in chains and rings, allowing families of related compounds and a very large range of natural and synthetic carbon compounds.

Recycling makes better use of the feedstocks and increases the overall amount of ammonia obtained, without claiming that each pass has a higher equilibrium yield.

The factory must first obtain or manufacture the ammonia and acid that will react to form it. These linked stages are integrated processes: the product of one process becomes a feedstock for another.

Some hydrocarbons obtained from crude oil are used as fuels. They are burned to release energy. But crude oil is also a feedstock for the petrochemical industry: it supplies raw materials that are changed by chemical reactions into other substances.