This part of GOV.UK is being rebuilt – find out what beta means

HMRC internal manual

Oils Technical Manual

Traders accounts, records and returns: Synthesis refineries

Simplified return for use in certain producers premises (“synthesis refineries”)

You may waive the need for synthesis refiners to calculate process and storage losses separately if you are satisfied that separate calculations are of no real value in any particular case.

A “synthesis refinery” is one whose primary purpose is to convert hydrocarbon oil into non-oil. An example is Humber Oil Refinery where the principal activity is the production of petroleum coke, and where the production of oil is secondary to that purpose.

Chemicals can be produced from a variety of petroleum fractions, first in what are primary conversion processes (cracking, steam conversion, pyrolysis, etc) where the fraction is directly converted to a derivative that is used either as a chemical or as an intermediate product for further processing.

Chemicals can also be produced by more complex processes involving the synthesis of chemicals from these primary products, e.g. alkylation to produce detergents.