Abstract: The importance of deep vacuum distillation technology is prominent because of inferior heavy oil is rolled out and atmospheric residual oil is difficult to be directly used as a raw material of RFCC. The atmospheric and vacuum distillation units are optimized as a whole in this paper. The tower internals technologies of the NS stripping plate, NS vacuum tower feed distributor, NS dedicated grille packing of washing section, NS dual flow compound tray, NS resistance wall jet type liquid distributor, NS layer tower liquid collector and a complete set of equipment of direct contact heat transfer technology are integrated. Based on the integrated technologies, the operation conditions can be optimized such as increasing atmospheric column distillation rate, improving separation effect of flash distillation section, and vacuum degree and temperature of flash distillation section in vacuum tower, reducing entrainment, reducing backflow in flash distillation section, creating micro wet distillation in vacuum tower bottom and improving cutting clarity. The deep-cut vacuum distillation with low cost and low energy consumption is achieved.