Application of exergetic methods in the analysis of different purifying techniques

Abstract

This paper provides the rationale for applying an exergetic method when evaluating the thermodynamics of column-rectification apparatuses, while reviewing the operating profiles of typical purifying columns and purifying columns with stripping modules operating under atmospheric pressure, vacuum, and with mechanical vapour recompression. Graphical representations of the purifying column's exergy balance are provided as Grassmann-Szargut diagrams. The exergy balance data showed that the total value of exergy loss is comparable between conventional purifying columns and those equipped with a stripping module (30.94% and 30.78% efficiency, respectively); moreover, exergy loss is lower in systems where the components operate under a vacuum (31.33% efficiency). For purifying columns that operate using mechanical vapour recompression, their exergetic efficiency is highest (32.6%), which indicates that the thermodynamic precision of system being studied increases when a heat pump is used as the primary source of high-grade energy supply in the column apparatus.