Aromatics are any hydrocarbons that contain a benzene ring (six carbon, unsaturated ring).
In a refinery, aromatics products mostly come from the BTX plant, where they are extracted from the reformate produced in the reformer. BTX plants also source pygas from steam crackers for aromatics extractions.
The most common aromatics produced by refiners are:
Benzene
Toluene
Xylene
Most refineries do not have BTX extraction and leave all of the produced aromatics in the reformate blended into gasoline. Consequently, aromatics are generally considered a specialty product.