Exergy analysis for a petroleum refinery

Abstract

The aim of exergy analysis is to detect and evaluate quantitatively thermodynamic imperfection of the process under consideration. Therefore, exergy analysis can indicate the possibility of thermodynamic improvement of the process, but only an economic analysis can decide the expediency of a possible improvement. In this work, exergy analysis was implemented on plant2 which is one of the complexes in the Bangchak refinery. The complex consisted of 9 units in total. The exergetic efficiency of the overall and individual units was determined using the operating plant data in associate with a provision II computer program. The results indicate that the exergetic efficiency of the complex is about 30% and the units equipped with furnaces yield lower exergetic efficiency. A number of modifications for thermodynamic improvement of the complex have been proposed as follows: i) to reduce a reflux ratio of distillation column, ii) to preheat air with effluent combustion gas, and iii) to replace a furnace with a high pressure steam heat exchanger in Catalytic Reforming Unit.