A technique for recovering heavy distillates from residue. The process lowers pressure under the level of the atmosphere, thereby reducing the temperature where hydrocarbons boil. This approach gives refiners access to molecules which would crack before they evaporated in a crude distiller.
process by which heavier cuts of crude not vaporized in the topping (atmospheric distillation) process are heated in a vaccum to accomplish their fractionation.
Distillation under reduced pressure (less the atmospheric) which lowers the boiling temperature of the liquid being distilled. This technique with its relatively low temperatures prevents cracking or decomposition of the charge stock.
Distillation that occurs at a pressure somewhat below atmospheric pressure. Lowering the pressure also lowers the boiling point of water, thus conserving energy by requiring less heat to bring about distillation.
A secondary refining process in which straight-run residue is distilled in a vacuum in order to separate more light hydrocarbons than through atmospheric distillation. The output of the process is vacuum gas oil, which can be used as feedstock for cracking units, and vacuum bottoms or residue, which are usually used as boiler fuel.
Vacuum distillation is a method of distillation whereby the pressure above the solution to be distilled is reduced to less than one Atmosphere causing evaporation of the most volatile liquid(s) (those with the lowest boiling points). Vacuum distillation is used with or without heating the solution.