Dynamic Controllability Comparison of Conventional Distillation Sequences and Dividing-Wall Columns with Upper and Lower Partitions Using the Desirability Function

Abstract

The aim of this study is to compare the controllability properties of conventional distillation sequences and dividing-wall columns with upper and lower partitions (DWCs). The controllability analysis methodology uses the Control Design Interface (CDI) module of Aspen Dynamics to obtain the state space representation of the studied systems. The frequency dependent controllability indices are calculated by Matlab on the basis of the matrices of the transferred state space representation. The study includes the examination of the conventional direct and indirect sequences and two DWCs systematically generated from the corresponding conventional sequences. Case studies are completed using ternary alcohol mixtures with different eases of separation. Results show that conventional distillation sequences have more favorable controllability properties than those of the DWCs if direct separation and mixtures with symmetrical ease of separation are considered. In the cases of mixtures with nonsymmetrical ease of separation, the indirect separation, the DWCs with lower partition show practically similar controllability features than those of the corresponding conventional sequences.

Comparison of Controllability Features of Extractive and Pressure Swing Distillations on the Example of Tetrahydrofuran Dewatering

“…The built-in Ziegler–Nichols tuning method of ASPEN is used. Time constants are determined on the basis of load rejection investigations with disturbances in the feed composition and feed flow rate . The methodology for controllability analysis is established on the basis of the study by Gabor and Mizsey, which is the fastest methodology for calculating the controllability indices within the frequency domain.…”

Thermodynamic and Exergy Analysis of Energy-Integrated Distillation Technologies Focusing on Dividing-Wall Columns with Upper and Lower Partitions

“…As it was mentioned previously, three ternary alcohol mixtures are used in the simulations identical to the ones in our previous study. 1 Components, relative volatilities (α ij ), and the ease of separation is listed in Table 1 for each mixture. Separation indices (SI) are calculated with eq 12:…”

“…Following the overall process synthesis concept it is vital to consider thermodynamic, economic, and controllability results simultaneously. In our previous study controllability properties of conventional distillation sequences and DWCs with upper and lower partition (Figures and ) have been examined through the separation of ternary alcohol mixtures. Conventional technologies proved to have favorable controllability results in the case of the studied mixtures.…”

“…Following the overall process synthesis concept 15 it is vital to consider thermodynamic, economic, and controllability results simultaneously. In our previous study 1 of conventional distillation sequences and DWCs with upper and lower partition (Figures 1 and 2) have been examined…”