Hydroskimming is one of the simplest types of refinery used in the petroleum industry[1] and still represents a large proportion of refining facilities, particularly in developing countries.
[3] A hydroskimming refinery is therefore more complex than a topping refinery (which just separates the crude into its constituent petroleum products by distillation, known as atmospheric distillation, and produces naphtha but no gasoline) and it produces gasoline.
The addition of catalytic reformer enables a hydroskimming refinery to generate higher octane reformate; benzene, toluene, and xylene; and hydrogen for hydrotreating units.
[4] However, a hydroskimming refinery produces a surplus of fuel oil with a relatively unattractive price and demand.
The Nelson Complexity Index, captures the proportion of the secondary conversion unit capacities relative to the primary distillation or topping capacity.