Optimization of ethylene process design

Conceptual process design and process optimization of triple-column pressure-swing distillation for the separation of ternary mixtures embedding two azeotropes with different feed composition via thermodynamic insights and genetic algorithm

Semiconductor and pharmaceutical industries often produce waste alcohol mixtures. This study discusses a reactive distillation process of a mixed alcohol feed containing n-amyl alcohol and n-hexanol to react with acetic acid to produce useful esters. In an earlier paper (Lee et al. Ind. Eng. Chem. Res. 2009 48, 7186–7204), optimal design of the same Type-III mixed-alcohol reactive distillation process containing n-butanol and n-amyl alcohol was developed. In that paper, the indirect sequence containing a reactive distillation column with heavier amyl acetate bottom product and a second column to produce butyl acetate gives the lowest total annual cost. In this study, with different mixed alcohol feed (although of the same reaction type), it is found that an alternative direct sequence design is much more economically favorable with 34% reduction in total annual cost as compared to the indirect sequence. The reason for the seemingly contradictory results can be explained by differences in relative volatilities of binary pairs in the stripping sections of the reactive distillation towers. Process intensification technology is also attempted to devise a thermally coupled reactive distillation configuration to further save 13% of the operating energy. The overall control strategy using tray temperatures is also proposed to maintain high-purity products despite various disturbances.

Optimal configuration of ternary distillation columns using heat integration with external heat exchangers

Energy-efficient extractive distillation combined with heat-integrated and intermediate reboilers for separating acetonitrile/isopropanol/water mixture

Optimal design and performance enhancement of heteroazeotropic and pressure-swing coupling distillation for downstream isopropanol separation

Design and optimization of Kemira-Leonard process for formic acid production

Intensified hybrid reactive-extractive distillation process for the separation of water-containing ternary mixtures

Design and control for recycle plants with heat-integrated separators

In this paper, pressure-swing distillation (PSD) is applied to separate pressure-insensitive minimum boiling azeotrope methanol/toluene via introducing chloroform as a light pressure-swing entrainer. The feasibility of this process is verified by analyzing the residue curve maps. Both partially and fully heat-integrated PSD processes are implemented. The steady-state designs of these processes are optimized based on total annual cost (TAC). In this extended PSD process, the high-pressure column (HPC) serves as the homogeneous azeotropic distillation column, while the low-pressure column (LPC) serves as the entrainer recovery column. It is found that the HPC has large temperature slope in the stripper section while with relatively flat trend above. This unique phenomenon makes it beneficial to reduce the energy consumption by preheating the feed and recycling stream using low-grade heat. Both conventional and partially heat-integrated extractive distillation processes with aniline as the entrainer are also implemented to compare the economy with these PSD processes. The results reveal that TAC of the partially heat-integrated extractive distillation process is higher than the conventional one. It also reveals that the partially and fully heat-integrated PSD processes have almost similar TAC and energy consumption, while the optimal PSD process has 5.39% reduction of TAC and 8.32% energy savings compared to the optimal conventional extractive distillation process. The dynamic controllability of this extended PSD is investigated by introducing ±20% disturbances of feed flow rate and composition for both partially and fully heat-integrated processes. The results reveal that the enthalpic state of the feed has crucial influence on the dynamic controllability, as it can influence the temperature profile and composition profiles of HPC greatly. Although the economic optimal PSD process shows weak controllability, robust control can be achieved under another superior design.

Design, optimization, and industrial-scale experimental study of a high-efficiency dividing wall column

Distillation column is a well-known unit operation in chemical and petrochemical industries for an intended separation task. However, the energy usage still becomes a problem particularly for a multicomponent system of distillation columns sequence. Therefore, this research aims to investigate the applicability of Thermal Pinch Analysis to be employed in a distillation columns sequence to solve the problem. The method is complemented by the sequencing method of Driving Force which leads to a novel method namely Energy Integrated Distillation Columns Sequence (EIDCS). This systematic method has been designed for optimal distillation columns sequence and further energy saving by Thermal Pinch Analysis. The Driving Force Sequence was firstly determined by the use of Driving Force Plot. Then the shortcut and rigorous simulations have been carried out and the resulting data were extracted for Thermal Pinch Analysis at a fixed value of ΔTmin at 10 °C. Next, the Problem Table Algorithm (PTA) was constructed to indicate the possible energy saving for the distillation columns sequence. Finally, the proposed Heat Exchanger Network (HEN) via Grid Diagram that satisfies the energy requirement was constructed. A case study of 6-component Aromatic Mixture has been selected to evaluate the proposed EIDCS method in this study.

Optimization and heat integration of hybrid R-HIDiC and pervaporation by combining GA and PSO algorithm in TAME synthesis

Flexible design and optimization of electronic-grade propylene glycol monomethyl ether acetate production via integrated reactive and pressure-swing distillation

Energy Integrated Distillation Column Sequence by Driving Force Method and Pinch Analysis

The concept of reactive-extractive distillation (RED) is not new and has gained significant attention as an innovative approach for separating azeotropic mixtures. Presently, there have been at least 18 studies on RED, exploring variations such as triple column RED (TCRED), double column RED (DCRED), and their intensified configurations like dividing-wall DCRED (DW-DCRED) or side-stream DCRED (SS-DCRED). However, a major drawback observed in all existing intensified RED studies is the inability to achieve energy savings, which contrasts with the outcomes of most conventional distillation system studies. To address this, we propose a new alternative configuration called extractive-reactive distillation (ED-RD) by rearranging the column sequence in DCRED. The ED-RD configuration achieves a substantial 7 % reduction in the total annual cost (TAC) compared to DCRED, primarily due to a reduced number of stages and the utilization of relatively cheaper low-pressure steam in the extractive distillation column (EDC). Furthermore, the intensified thermally coupled ED-RD (TC-ED-RD) configuration demonstrates superior performance, achieving an impressive 21 % reduction in TAC compared to the proposed ED-RD configuration, mainly driven by a significant decrease in total reboiler energy consumption. Overall, the TC-ED-RD configuration excels with a remarkable 28 % reduction in total reboiler energy consumption and a 27 % decrease in TAC compared to DCRED. This reflects the potential of incorporating process intensification techniques to the proposed configuration to achieve substantial energy and cost savings, in contrast to the limitations observed in the conventional RED systems.