Predicting Multiple Steady States in Equilibrium Reactive Distillation. 1. Analysis of Nonhybrid Systems

1999 ◽  
Vol 38 (4) ◽  
pp. 1633-1648 ◽  
Author(s):  
Thomas E. Güttinger ◽  
Manfred Morari
Keyword(s):  
Reactive Distillation ◽  
Steady States ◽  
Multiple Steady States

scholarly journals Intensification of Reactive Distillation for TAME Synthesis Based on the Analysis of Multiple Steady-State Conditions

Processes ◽  
2018 ◽  
Vol 6 (12) ◽  
pp. 241 ◽  
Author(s):  
Takehiro Yamaki ◽  
Keigo Matsuda ◽  
Duangkamol Na-Ranong ◽  
Hideyuki Matsumoto
Keyword(s):  
Liquid Flow ◽  
Reactive Distillation ◽  
Steady States ◽  
Vapor Flow ◽  
Multiple Steady States ◽  
Reflux Ratio ◽  
Flow Rates ◽  
Reaction Conversion ◽  
Reaction Performance ◽  
Separation Performances

Our previous study reported that operation in multiple steady states contributes to an improvement in reaction conversion, making it possible to reduce the energy consumption of the reactive distillation process for tert-amyl methyl ether (TAME) synthesis. This study clarified the factors responsible for an improvement in the reaction conversion for operation in the multiple steady states of the reactive distillation column used in TAME synthesis. The column profiles for those conditions, in which multiple steady states existed and those in which they did not exist, were compared. The vapor and liquid flow rates with the multiple steady states were larger than those when the multiple steady states did not exist. The effect of the duty of the intermediate condenser, which was introduced at the top of the reactive section, on the liquid flow rate for a reflux ratio of 1 was examined. The amount of TAME production increased from 55.2 to 72.1 kmol/h when the intermediate condenser was operated at 0 to −5 MW. Furthermore, the effect of the intermediate reboiler duty on the reaction performance was evaluated. The results revealed that the liquid and vapor flow rates influenced the reaction and separation performances, respectively.

Effect of Operating Conditions on the Multiple Steady States in Reactive Distillation

2014 ◽  
Vol 40 (3) ◽  
pp. 244-249 ◽  
Author(s):  
Takehiro Yamaki ◽  
Masahiro Shishido ◽  
Keigo Matsuda ◽  
Hideyuki Matsumoto
Keyword(s):  
Reactive Distillation ◽  
Steady States ◽  
Operating Conditions ◽  
Multiple Steady States

Theoretical study on transesterification in a combined process consisting of a reactive distillation column and a pervaporation unit

2011 ◽  
Vol 65 (2) ◽  
Author(s):  
Zuzana Švandová ◽  
Jozef Markoš
Keyword(s):  
Steady State ◽  
Distillation Column ◽  
Reactive Distillation ◽  
Steady States ◽  
Multiple Steady States ◽  
Process Unit ◽  
Steady State Analysis ◽  
Operation Temperature ◽  
State Behaviour ◽  
State Analysis

AbstractSteady state analysis of a combined hybrid process consisting of a reactive distillation column, pervaporation unit, and a distillation column is presented. This process configuration was first presented by Steinigeweg and Gmehling (2004) for the transesterification of methyl acetate and butanol to butyl acetate and methanol. This system is characteristic for its low reaction rate and complex phase equilibrium. Steinigeweg and Gmehling (2004) have shown that the combination of reactive distillation and pervaporation is favourable since conversions close to 100 % can be reached with a reasonable size of the reactive section in the reactive distillation column. The aim of this paper is to show that although high conversion can be achieved, very complicated steady state behaviour must be expected. The presented analysis is based on mathematical modelling of a process unit, where the steady-state analysis, including continuation and bifurcation analyses, was used. Multiple steady states were predicted for the studied system; three steady states with conversions higher than 98 %. However, not all predicted steady states met the maximal allowed temperature condition in the reactive section (catalyst maximal operation temperature of 393 K). The presence of multiple steady states reduces the operability and controllability of the reactive distillation column during its start-up and during the occurrence of any variation of operating parameters because the system can be shifted from one steady state to another one (concurrent exceeding the maximal allowed temperature) with unwanted consequences, e.g. production loss. Therefore, design and subsequent operation of such a complicated system is an ambitious task requiring knowledge of any possible system behaviour.

Multiple steady states in a CSTR with total condenser: Comparison of equilibrium and nonequilibrium models

2006 ◽  
Vol 60 (6) ◽  
Author(s):  
Z. Švandová ◽  
J. Markoš ◽  
L’. Jelemenský
Keyword(s):  
Distillation Column ◽  
Dynamic Behaviour ◽  
Reactive Distillation ◽  
Steady States ◽  
Multiple Steady States ◽  
Reflux Ratio ◽  
Start Up ◽  
State Behaviour ◽  
Steady State Behaviour ◽  
Nonequilibrium Models

AbstractComparison of equilibrium and nonequilibrium models of a CSTR with total condenser focused on the multiple steady states and dynamic behaviour was carried out. The steady-state behaviour of the model system, MTBE synthesis from methanol and isobutene in a reactive distillation column, was studied in terms of the input parameters, i. e. feed flow rate of methanol or butenes, reflux ratio, and mass of catalyst. The dynamic behaviour of the system during the start-up was investigated and perturbations of manipulated variables were found to cause transitions between the parallel steady states.

Multiple steady states in reactive distillation: kinetic effects

2002 ◽  
Vol 26 (1) ◽  
pp. 81-93 ◽  
Author(s):  
Fengrong Chen ◽  
Robert S. Huss ◽  
Michael F. Doherty ◽  
Michael F. Malone
Keyword(s):  
Reactive Distillation ◽  
Steady States ◽  
Multiple Steady States ◽  
Kinetic Effects
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