Vacuum Residual is the bottom of the barrel . It includes asphalt and some coke . Pitch is a thick, black, sticky material. It is left behind when the lighter components of coal tar or petroleum are distilled off. Asphalt is a high boiling component of crude oil .
Tars are byproducts formed when coke is made from coal or charcoal is made from wood.
It is a thick, complex, oily black mixture of heavy organic compounds very similar to pitch or asphalt, though from a different source.