Design of a Repsol's refinery gas concentration unit

Identifier:  TFG:2471

Handle: https://hdl.handle.net/20.500.11797/TFG2471

Authors:  Alvarado Izáziga, Andrés Felipe

Abstract:
The aim of this project is to conceptually design two Gas Concentration Units in sufficient detail to be able to compare them economically and, therefore, decide which one is more profitable. On the one hand, the Gas Concentration Unit currently used at the Repsol refinery in Tarragona will be taken as reference. It is configured from an ensemble of two absorbers and a stripper that works among 10 and 11 bar. On the other hand, an alternative will be designed with the premise of a reduction of equipment in comparison to Repsol's option. Consequently, the ensemble absorber/stripper will be substituted for one deethanizer distillation column that will lead to an increase of pressure to 38 bar. The design of both Units has been performed by using the simulator Aspen HYSYS and has been complemented with an energetic study done through the software Aspen Energy Analyzer. The study has shown that it is only possible to perform an energetic integration in the case of the Absorber/Stripper's configuration; however, the Deethanizer's configuration consumes fewer utilities than the former one. Lastly, economic evaluation and comparison have been done on both configurations. The initial investment required during the first year of the project would be higher in the case of the Deethanizer's configuration, since the cost of the equipment is 2.20 million euros more expensive, due to the higher pressure used in the system. In addition, although the Deethanizer's configuration consumes fewer utilities, the Absorber/Stripper's spends 2.80 million fewer euros on annual production. Therefore, it can be concluded – and confirmed by using the Net Present Value method- that the Absorber/Stripper's configuration used by Repsol is more profitable than the proposed alternative.