Methods and apparatus for vacuum separation are described. The method includes heating a feed comprising a mixture of light and heavy hydrocarbons in a first heating zone. The heated feed is flashed in a flash drum to form a liquid stream and a vapor stream. The liquid stream is heated in a second heating zone. The heated liquid stream is introduced into a vacuum distillation column through a first inlet. The vapor stream from the flash drum is introduced into the vacuum distillation column through a second inlet located above the first inlet, the vapor stream of the flash drum being in fluid communication with the vacuum distillation column.