Dynamics and control of thermal- versus electrical-driven pressure-swing distillation to separate a minimum-boiling azeotrope
Journal
Separation and Purification Technology
Journal Volume
280
Date Issued
2022
Author(s)
Abstract
The implementations of heat integration (HI, thermal-driven), vapor recompression (VRC, electrical-driven), and self-heat recuperation (SHR, electrical-driven) in pressure-swing distillation (PSD) are available for providing energy saving and CO2 emission reduction over the conventional design (CONV, thermal-driven), exemplified by a minimum-boiling tetrahydrofuran/water. Approximately a 20 % decrease in total annual cost (TAC) and over 25 % CO2 emission reduction can be reached by using these measures. However, these steady-state advantages sometimes go along with decreases in controllability, so it is necessary to investigate the dynamics and control of these highly integrated and interacting processes. Robust temperature control structures based on decentralized proportional-integral (PI) feedback controllers are developed to tackle ± 20% disturbances in throughput and feed composition. For the thermal-driven processes, the PSD-CONV is easily controlled with the single-end control strategy. Based on that, the effective control of PSD-HI is achieved by either pressure compensation or bypass strategy. Regarding the complicated electrical-driven arrangements, the dynamic responses of PSD-VRC and PSD-SHR indicate their controllability is comparable to those of a regular sequence. These results demonstrate that there are no conflicts between the steady-state advantages and dynamic controllability for this specific separation. Meanwhile, these electrical-driven processes can be considered to extend to other minimum-boiling azeotropes owing to their economic and environmental advantages. ? 2021 Elsevier B.V.
Subjects
Dynamics and control
Heat integration
Hot vapor bypass strategy
Pressure-swing distillation
Vapor recompression
Carbon dioxide
Controllability
Distillation
Dynamics
Energy conservation
Two term control systems
CO 2 emission
Emission reduction
Hot vapor
Minimum boiling azeotropes
Pressure swing distillation
Thermal driven
Vapour recompression
Emission control
SDGs
Type
journal article