Analysis of Possible Negative Values for 2nd Law Efficiencies in an Extractive Distillation System

Abstract

Objective: The objective of this study is to investigate the occurrence of negative values for the second law efficiencies in distillation columns, in order to evaluate the relationship between these efficiencies, energy consumption and remixing effect. Theoretical Framework: This topic presents the main concepts and theories that underpin the research. The thermodynamic concepts related to the first and second laws of thermodynamics are highlighted, providing a solid basis for understanding the context of the investigation. Method: The methodology adopted for this research involves the simulation of the acetone/methanol system, in Aspen Plus, using two solvents, DMSO and water. The efficiencies of the second law, energy consumption and remixing effect were evaluated for different operational conditions. Results and Discussion: The results obtained revealed that not all operational conditions that present greater thermodynamic efficiency result in lower energy consumption. In addition, heat demand is directly related to lost work. In the discussion section, these results are contextualized in light of the theoretical framework, highlighting the implications and relationships identified. Possible discrepancies and limitations of the study are also considered in this section. Research Implications: The practical and theoretical implications of this research are discussed, providing insights into how the results can be applied or influence practices in the field of thermodynamic evaluation of distillation columns. These implications may include improving the sustainability of distillation processes by identifying and minimizing sources of irreversibilities. Originality/Value: This study contributes to the literature by conceptually addressing the interpretation of thermodynamic efficiencies of distillation columns, in addition to providing a detailed analysis of the relationship between efficiency, energy consumption and remixing effect. The relevance and value of this research are evidenced by perspectives for the thermodynamic optimization of distillation processes.