Atmospheric residue and vacuum wax oil

The feed to the vacuum distillation tower is atmospheric residue. The various properties of vacuum wax oil are better than those of atmospheric residue because the gums and asphaltenes in it are removed through vacuum distillation.

Atmospheric pressure residue is heated in a vacuum furnace and then fed into a vacuum distillation column as its feed. Under vacuum conditions, the residue is separated into first-line diesel, second-line wax oil, third-line catalytic feed, fourth-line vaporized oil, as well as vacuum residue and vacuum wax oil, depending on the boiling points of the different components. The quality parameters of vacuum wax oil are better than those of ordinary residue because ordinary residue contains gums and asphaltenes from the vacuum residue; these gums and asphaltenes have high boiling points and high carbon residue content. Under vacuum conditions, vacuum wax oil and these gums and asphaltenes are separated due to their differing boiling points, which is why the quality parameters of wax oil are superior to those of ordinary residue. The details regarding the separation process can be found in the technical Q&A section, so they will not be explained in detail here

Under different operating conditions, the boiling point of the oil is reduced by vacuuming to produce diesel and wax oil, while most of the original gums and asphaltenes remain in the residue.