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Plant-wide Design and Control of Lactic acid Recovery Processes by Reactive Distillation with Different Alcohols
Date Issued
2014
Date
2014
Author(s)
Su, Chien-Yuan
Abstract
Process designs for the continuous recovery of lactic acid from fermentation broth by reactive distillation (esterification and hydrolysis with C1 to C4 alcohols) are developed and optimized to minimize cost. The best designs are qualitatively different for different alcohols because of differing volatility ranking of reactants and products and the formation of a two liquid phase zone in some cases. The results suggest that the methanol and butanol processes are the most attractive solution. The costs of these two processes are similar, and the ranking depends on the payback period (when payback period is 3 butanol is more economical, vise versa). The ethanol and isopropanol processes are more expensive because an entrainer is required to break the alcohol/water azeotrope. Control structures for the methanol and butanol processes are designed and tested for the performance through feed flowrate, lactic acid composition and impurity composition disturbances.
Designed control structures can be separated into 2 scenarios. One is 1-recycle stream of recovered alcohol. Another one is 2-recycle streams with recovered alcohol and water. Methanol system can implement 2 recycle streams and butanol system can implement 1 recycle stream. Results show that 1-recycle scenario is more robust than 2-recycle scenario because it has a more straight forward flowsheet. Combined composition and temperature control structures can handle more disturbances and maintain the constraints. Both methanol and butanol control structures can pass flow rate and composition disturbances. Methanol control structure is more robust than butanol control structure because it can handle the disturbances in less time.
Designed control structures can be separated into 2 scenarios. One is 1-recycle stream of recovered alcohol. Another one is 2-recycle streams with recovered alcohol and water. Methanol system can implement 2 recycle streams and butanol system can implement 1 recycle stream. Results show that 1-recycle scenario is more robust than 2-recycle scenario because it has a more straight forward flowsheet. Combined composition and temperature control structures can handle more disturbances and maintain the constraints. Both methanol and butanol control structures can pass flow rate and composition disturbances. Methanol control structure is more robust than butanol control structure because it can handle the disturbances in less time.
Subjects
乳酸純化
反應蒸餾
最適化流程
動態控制
Type
thesis
File(s)
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Name
ntu-103-D96524019-1.pdf
Size
23.54 KB
Format
Adobe PDF
Checksum
(MD5):b093748e1b45e559d028470198dc3cf2