(145f) Optimal Operation of Middle-Vessel Batch Distillation
AIChE Annual Meeting
2023
2023 AIChE Annual Meeting
Separations Division
Distillation and Absorption Processes Fundamentals, Developments, Optimization, and Applications II
Tuesday, November 7, 2023 - 2:35pm to 3:00pm
Optimization of batch distillation can be performed to maximize productivity (or separation efficiency) or minimize energy consumption (or maximize energy efficiency). Previously, it has been shown that these objectives conflict each other and can lead to practically limiting designs [2]. In this work, a new performance indicator, overall performance index (OPI), is defined for a MVBD column to capture the trade-off between separation and energy efficiency. The optimal operation policy for MVBD is then formulated to maximize this index. Specifically, the trajectories of the two reflux flows (R1 and R2) and reboiler duty (Qreboiler) are obtained to maximize OPI of a batch. Subsequently, a feedback control system is designed to track this optimal operational policy.
The proposed work helps address key operational issues, such as initial feed distribution and constant versus variable holdup policy. Specifically, physical insights are drawn from the obtained optimal solutions to relate the observed performance with the properties (e.g. relative volatility, relative cost of products, etc.) of the feed. The performance of the MVBD column is compared with the conventional multi-cut operation via simulations to demonstrate the benefits of the proposed work.
References:
[1] Davidyan, A. G., Kiva, V. N., Meski, G. A., & Morari, M. (1994). Batch distillation in a column with a middle vessel. Chemical Engineering Science, 49(18), 3033-3051.
[2] Vibhute, M. M., & Jogwar, S. S. (2020). Optimal operation and tracking control of vaporârecompressed batch distillation. AIChE Journal, 66(12), e17049.