Also known as: vacuum gasoil
VGO is one of the two outputs of the vacuum distillation tower (along with vacuum resid). VGO is the lighter material of the two.
The primary use of VGO is as feed to cracking units such as the FCC or the hydrocracker. These units upgrade VGO into more valuable products, namely gasoline and diesel.
If not upgraded, VGO is blended into residual fuel oil. However, this is fairly rare since the value of VGO is much greater as a feed into upgrading. Often, if a refinery lacks enough cracking to upgrade the VGO it generates, it will sell this as an intermediate to another refinery, rather than downgrading it by blending into residual fuel oil.
VGO is often sub-divided into a lighter and heavier fraction called LVGO and HVGO, respectively.