Process Control of Reactive Distillation for Esterification of Butanol and Pentanol Mixtures
Date Issued
2009
Date
2009
Author(s)
Kou, Hung-Jui
Abstract
The objective of this work is to design a feasible control system for the esterifications process of mixed butanol and pentanol (Yen, 2008[6]). It is found that thebovementioned process has a steady-state bifurcation. The optimal operating conditiont the aqueous split ratio (abbrev ASR) of 0.66, which minimizes the total annual costTAC), is a turning point on the bifurcation trajectory. Thus, the optimal point at ASRof.66 is not feasible for designing control system. A more conservative ASR (i.e. 0.75)or control system design is thus used.n constructing the inventory loops, it is found that the stable range of theraditional inventory loops is too small to operate. Thus, an alternative design, whichses reboiler duty of RD column to control the RD sump level, is used. The results fromimulation show that good performance in both dynamic response and range ofisturbance management can be achieved with this chosen ASR at 0.75.fter fixing the inventory loops, temperature control loops are designed to controlhe quality of products. Three control schemes (CS-1, CS-2, CS-3) with Multi-loopontrol are thus proposed. By simple analyses, it is found that only CS-3 is feasible foristurbance rejection. As a consequence, CS-3 only is taken for further study. Controllerairing is determined by using the SVD and RGA analyses, and controller parametersre tuned by using ATV test with Tyreus and Luyben’s tuning rules[22]. Disturbancesrom feed rate, feed composition changes are used to test the control performance.imulation results show that at ASR of 0.75, the control scheme CS-3 works well in allspects.
Subjects
Reactive distillation
esterification
control scheme
multi steady-state
bifurcation
step change
Type
thesis
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