Energy saving in a crude distillation unit by a preflash implementation

After the 70s energy crisis the revamping of plants designed before this date is very attractive for improving energy recovery and lowering operation costs. A typical case is the oil refinery plant where an intensive usage of energy takes place and is a promising case for the application of energy saving solutions. In this work we focused our attention to an industrial crude oil distillation unit, evaluating the possibility to modify the feed conditions by installing a preflash drum or a preflash plate column. Real data plant were collected to obtain a reliable simulation of the unit by means of the software package Aspen Plus 13.0. To characterize the crude oil fed the TBP curve was used. The results obtained were compared with the plant data in terms of flow rate and product quality utilizing the ASTM D-86 curves and a good agreement was obtained. According to the specialized literature the preflash drum/column was placed at the end of the pre-heat train, just before the column furnace. The furnace is the bottleneck of the plant and with both the preflash devices it is possible to lower its energy consumption. However the energy reduction is associated to the decrease of one kind of distillates (light or middle). The choice of the best preflash device was made according to the production asset of the plant.