A Design Methodology for Retrofit of Crude Oil Distillation Systems

Retrofit of crude oil distillation systems is a non-trivial problem with many degrees of freedom and constraints. This work proposes a systematic retrofit methodology for increasing the throughput to crude oil distillation systems, embedded in a computational tool with mass and energy balance results from rigorous simulations, hydraulic correlations for valve trays and structured packings and a retrofit model for heat exchanger networks. The feasibility of retrofit options is assessed against constraints related to product specifications, jet flooding and liquid load per weir length in the main fractionator and side strippers and the required area for heat exchangers in the heat exchanger network (HEN). The methodology is applied to an existing crude oil distillation system; the results show the impact of increasing throughput on column hydraulics and heat transfer area requirements. Retrofit solutions are proposed for relieving hydraulic bottlenecks and minimizing impact on the HEN by varying column operating conditions.