A glossary of common terms and abbreviations used in the industry, with links to more in-depth articles on key words
Vacuum distillation - (VDU) a refinery process unit that separates the atmospheric resid generated by the atmospheric distillation tower into its components by distilling the resid under a vacuum
Vacuum resid - (VR) the heaviest of the distillation cuts
Value chain optimization - (VCO) part of a refining organization responsible for optimizing sourcing and use of feedstocks and production and placement of refined products
Van Gogh (crude) - a heavy, sweet crude grade produced in the Australia
Vanadium - one of the (contaminant) metals that occurs naturally in crude oil
Variable cash margin - one common measure of refinery margin or economic performance. Variable cash margin is typically calculated per barrel of crude oil processed and is equal to the gross margin, less variable costs such as energy, catalyst and chemicals
Variable costs - any costs that are tied to the volume of crude that a refinery processes, in contrast to fixed costs which are not volume dependent
Varsol - a naphtha range refined product used as an extraction solvent, cleaner (paint thinner) or degreaser
Vasconia (crude) - a heavy, sour crude grade produced in Colombia
Vapor lock - (VL) a condition when gasoline fuel vapor forms somewhere in the fuel system of a vehicle, reducing or stopping the flow of fuel to the engine
Vapor lock index - (VLI) the measure used to control the tendency of gasoline to form vapor lock in most markets outside of US
Vapor pressure - a measure of the volatility of a fuel, or the degree to which it vaporizes at a given temperature
Vapor pressure index - index used to calculate the vapor pressure of a gasoline blend comprised of blendstocks that have different vapor pressures
VBI - (Viscosity blend index) an index used to calculate the viscosity of a blend of components of different viscosity
VCO - (Value chain optimization) part of a refining organization responsible for optimizing sourcing and use of feedstocks and production and placement of refined products
before they are fed to the FCC
Very large crude carrier - (VLCC) a class of large oil tanker, larger than Suezmax and smaller than ULCC
VGO - (vacuum gasoil) one of the two outputs of the vacuum distillation tower (along with vacuum resid). VGO is the lighter material of the two
VGO hydrotreater - a hydrotreater used to reduce the sulfur in FCC feedstocks such as VGO
Vincent (crude) - a heavy, sweet crude grade produced in the Australia
Visbreaker - a mild bottoms conversion unit. It upgrades vacuum resid by cracking it so that viscosity is reduced and the amount of high-value cutter stock required to blend it into residual fuel oil is reduced
Viscosity - an important quality specification for residual fuel oil. Specifically, it is a measure of a liquid's resistance to flow
Viscosity blend index - (VBI) an index used to calculate the viscosity of a blend of components of different viscosity
VLCC - (Very-large crude carrier) a class of large oil tanker, larger than Suezmax and smaller than ULCC
VOCs - (Volatile organic compounds) compounds in fuels (especially gasoline) that when released into the atmosphere (usually from evaporative emissions) react to form air pollution