Intensifying petroleum fractionators through internal partial condensation in place of pump-around

Abstract

Conventional crude distillation unit uses pump-around, or direct contact heat exchange, to remove extra heat and provide internal reflux flow. From the perspective of heat and mass transfer, pump-around streams experience two heat transfer processes in low efficiency, while essentially not contributing to distillation. Novel internal partial condensation sections are proposed to replace unwelcomed pump-around zones by cooling the rising vapor with the cold feed crude oil via a new plate-type heat exchanger inside the column. According to a simulative case study through building up the virtually assembled process within Aspen Plus, equipment size and pressure drop are reduced as the required vapor/liquid flow rate is decreased. For an existing petroleum fractionator, energy consumption reduction touches 11.88% while product yield is improved by 0.74%. This achievement is inspired by novel patented internal condensers featured of very low pressure drop, invented for ultrahigh vacuum distillation cases. These results infer industrial application prospects for advanced design or revamp for larger production capacity, or higher energy efficiency, or both. The developments and innovations in equipment facilitate the progress or intensification of the process as shown in this paper.