Methodology for the design and evaluation of distillation systems: Exergy analysis, economic features and GHG emissions

Abstract

This work presents a process design methodology that evaluates the distillation systems based on exergetic, economic, and greenhouse gas (GHG) emission aspects. The aim of the methodology is to determine how these three features should be applied in process design to obtain information about the accuracy of the design alternatives. The methodology is tested and demonstrated on three different energy-integrated distillation systems: the direct sequence with backward heat-integration (DQB), fully thermally coupled distillation column (FTCDC), and sloppy distillation system with forward heat-integration (SQF). The average relative emission saving is the highest for the DQB scheme and this sequence shows the most flexible range of use. The case studies prove the accuracy of our evaluation methodology. On the other hand, it highlights and demonstrates that the exergy analysis can predict the results of the economic study and the environmental evaluation to make the decisions, associated with process design, much simpler. V

Ranking of rectification structures separating quaternary mixtures with exergy analysis

“…The backwards heat integrated direct sequence (DQB) system has good efficiencies in all cases and can be recommended for any applications. Good performance of the DQB structure is in correspondence with many previous studies [2,13,14,20]. DQB is a simple, reliable structure with good properties, its usage is recommended, especially for retrofitting, where the application of newer, complicated structures would be impossible.…”

“…A simple enthalpy balance fails to indicate these differences between different forms of energy. Published works either discuss the development of exergy analysis methods and expressive parameters to quantify exergy loss and thermodynamic efficiency of distillation columns [1,4,5,17,30] or use the basic equations of thermodynamics related to exergy to make the calculations to obtain thermodynamic efficiency of distillation systems [13,14,23,24]. Exergy analysis can be applied for the examination of complex distillation plants also to locate process sections where exergy losses are high and improvements are possible [21,24].…”

“…Such sensitive systems would not produce constant quality which is disadvantageous from an economic point of view; moreover, inappropriate product quality requires additional separational work, thus more energy. Other works are investigating different new improvements on thermally coupled distillation systems [7,11,12,14,15,18,[27][28][29]. These topics all show the importance and actuality of saving energy, especially in such energy consuming processes like distillation.…”

“…These papers discuss the integrated technological, economical or environmental design together [11,28,29]. Kencse and Mizsey [14] presented a simpler way to aggregate these aspects with the desirability func-tion. This paper is showing the usefulness of exergy analysis through ranking of commonly used distillation systems that may be included in the selection of distillation structures and complex design methodologies.…”

A novel application of exergy analysis: Lean manufacturing tool to improve energy efficiency and flexibility of hydrocarbon processing

“…Kencse and Mizsey use exergy analysis in parallel with greenhouse gas emission [21] and later combined with both greenhouse gas emission and cost assessment [5].…”