Reactive Distillation for Acetates from Butanol and Pentanol Mixtures
Date Issued
2008
Date
2008
Author(s)
Yen, Ling-Ting
Abstract
This work presents a feasible design for esterifications of n-butanol (BuOH) and n-amyl alcohol (AmOH) mixtures with acetic acid (HAc) and finds the rules of feed location for alternating system. NRTL-HOC thermodynamic models are used for modeling the vapor-liquid and vapor-liquid-liquid equilibrium. The reactions are catalyzed by using Amberlyst-15 catalyst. There are two alternative arrangements regarding the alcohol mixtures as feed for reactive distillation. In the first, separation of the mixture into pure alcohols goes first and esterifying with RD follows. In the second, esterification by RD directly goes first and purifying the products goes next. Two designs for products separation after the RD column are considered: (1)Direct Sequence: Reactive distillation (RD) produces water (H2O) at the top and produces butyl acetate (BuAc) and amyl acetate (AmAc) at the bottom. (2)Indirect Sequence: RD produces H2O and BuAc at the top and produces AmAc at the bottom. Besides, Indirect Sequence has two alternative flowsheets-Organic reflux and Aqueous reflux. After comparing the total annual cost (TAC), Aqueous reflux is more economical. Aqueous reflux includes a RD and a distillation column. The RD bottom obtains the heaviest product AmAc, and the top RD overhead is fed to a decanter for water separation. Part of aqueous phase as entrainer is refluxed to the RD and forms the azeotrope with BuAc. Organic phase enters to another distillation column and pure ester BuAc is obtained from the bottom.s the boiling point of acid between the alcohols (BuOH < HAc < AmOH) is called alternating system. Feed location of alternating system is also an important issue in this study. Reaction kinetics is varied to seek the effect on the feed location. It is found that the boiling point of mixed alcohols (Tb,mix) and the reaction rate constant (k) are the important factors to be considered in determining the feed location of alternating system.
Subjects
reactive distillation, alcohol mixtures
esterification
aqueous reflux
feed location
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-97-R95524066-1.pdf
Size
23.53 KB
Format
Adobe PDF
Checksum
(MD5):d6f808146addf5022df7d217700627c6