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Energy saving in conventional and uncoventional batch reactive distillation: application to hydrolysis of methyl lactate systemEdreder, E.A., Emtir, M., Mujtaba, Iqbal M. January 2014 (has links)
No / In this work, energy consumption in a middle vessel batch reactive distillation (MVBRD) column is considered for the production of lactic acid via hydrolysis of methyl lactate. A dynamic optimization problem incorporating a process model is formulated to minimize the batch time which consequently minimizes the total energy consumption. The problem is subject to constraints on the amount and purity of lactic acid. The optimisation variables are reflux ratio and/or reboil ratio which are treated as piecewise constant. The earlier work of the authors on energy consumption in conventional batch reactive distillation column (CBRD) for the same reaction system is used for comparative analysis with the energy consumption in MVBRD. As an example, for a given separation task, the optimization results show that MVBRD is capable of saving over 23 % energy compared to energy consumption in CBRD column for the same task.
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Modelling and Optimization of Conventional and Unconventional Batch Reactive Distillation Processes. Investigation of Different Types Batch Reactive Distillation Columns for the Production of a Number of Esters such as Methyl Lactate, Methyl Decanoate, Ethyl Benzoate, and Benzyl Acetate using gPROMSAqar, Dhia Y. January 2018 (has links)
The synthesis of a number of alkyl esters such as methyl lactate, methyl decanoate, and ethyl benzoate via esterification in a reactive distillation is quite challenging. It is due to the complexity in the thermodynamic behaviour of the chemical species in the reaction mixture in addition to the difficulty of keeping the reactants together in the reaction section. One of the reactants (in these esterification reactions) having the lowest boiling point can separate from the other reactant as the distillation continues. This can result in a significant drop in the reaction conversion in a conventional reactive distillation whether it is a batch or a continuous column.
To overcome this challenge, new different types of batch reactive distillation column configurations: (1) integrated conventional (2) semi-batch (3) integrated semi-batch (4) integrated dividing-wall batch distillation columns have been proposed here.
Four esterification reaction schemes such as (a) esterification of lactic acid (b) esterification of decanoic acid (c) esterification of benzoic acid (d) esterification of acetic acid are investigated here. A detailed dynamic model based on mass, energy balances, chemical reaction, and rigorous thermodynamic (chemical and physical) properties is considered and incorporated in the optimisation framework within gPROMS (general PROcess Modelling System) software.
It is found that for the methyl lactate system, the i-SBD operation outperforms the classical batch operations (CBD or SBD columns) to satisfy the product constraints. While, for the methyl decanoate system, the i-DWCBD operation outperforms all CBD, DWBD and sr-DWBD configurations by achieving the higher reaction conversion and the maximum product purity. For the ethyl benzoate system, the performance of i-CBD column is superior to the CBD process in terms of product quality, and conversion rate of acid. The CBD process is found to be a more attractive in terms of operating time saving, and annual profit improvement compared to the IBD, and MVD processes for the benzyl acetate system. / The Higher Committee for Education Development in Iraq (HCED)
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Methyl lactate synthesis using batch reactive distillation: Operational challenges and strategy for enhanced performanceAqar, D.Y., Rahmanian, Nejat, Mujtaba, Iqbal M. 13 December 2015 (has links)
Yes / Batch reactive distillation is well known for improved conversion and separation of desired reaction products. However, for a number of reactions, the distillation can separate the reactants depending on their boiling points of them and thus not only reduces the benefit of the reactive distillation but also offers operational challenges for keeping the reactants together. Methyl lactate (ML) synthesis via the esterification of lactic acid (LA) with methanol in a reactive distillation falls into this category and perhaps that is why this process has not been explored in the past. The boiling points of the reactants (LA, methanol) are about 490 K and 337 K while those of the products (ML, water) are 417 K and 373 K respectively. Clearly in a conventional reactive distillation (batch or continuous) methanol will be separated from the LA and will reduce the conversion of LA to ML significantly.
Here, first the limitations of the use of conventional batch distillation column (CBD) for the synthesis of ML is investigated in detail and a semi-batch reactive distillation (SBD) configuration is studied in detail where LA is the limiting reactant and methanol is continuously fed in excess in the reboiler allowing the reactants to be together for a longer period. However, this poses an operational challenge that the column has to be carefully controlled to avoid overflow of the reboiler at any time of the operation. In this work, the performance of SBD for the synthesis of ML is evaluated using model based optimization in which operational constraints are embedded. The results clearly demonstrate the viability of the system for the synthesis of ML.
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Significant thermal energy reduction in lactic acid production processMujtaba, Iqbal M., Edreder, E.A., Emtir, M. January 2012 (has links)
No description available.
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Improvement of multicomponent batch reactive distillation under parameter uncertainty by inferential state with model predictive controlWeerachaipichasgul, W., Kittisupakorn, P., Mujtaba, Iqbal M. January 2013 (has links)
yes / Batch reactive distillation is aimed at achieving a
high purity product, therefore, there is a great deal to find an
optimal operating condition and effective control strategy to
obtain maximum of the high purity product. An off-line
dynamic optimization is first performed with an objective
function to provide optimal product composition for the batch
reactive distillation: maximum productivity. An inferential
state estimator (an extended Kalman filter, EKF) based on
simplified mathematical models and on-line temperature
measurements, is incorporated to estimate the compositions in
the reflux drum and the reboiler. Model Predictive Control
(MPC) has been implemented to provide tracking of the
desired product compositions subject to simplified model
equations. Simulation results demonstrate that the inferential
state estimation can provide good estimates of compositions.
Therefore, the control performance of the MPC with the
inferential state is better than that of PID. In addition, in the
presence of unknown/uncertain parameters (forward reaction
rate constant), the estimator is still able to provide accurate
concentrations. As a result, the MPC with the inferential state
is still robust and applicable in real plants.
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Modelling and optimisation of batch distillation involving esterification and hydrolysis reaction systems : modelling and optimisation of conventional and unconventional batch distillation process : application to esterification of methanol and ethanol using acetic acid and hydrolysis of methyl lactate systemEdreder, Elmahboub A. January 2010 (has links)
Batch distillation with chemical reaction when takes place in the same unit is referred to as batch reactive distillation process. The combination reduces the capital and operating costs considerably. Among many different types of batch reactive distillation column configurations, (a) conventional (b) inverted (c) semi-batch columns are considered here. Three reaction schemes such as (a) esterification of methanol (b) esterification of ethanol (c) hydrolysis of methyl lactate are studied here. Four different types of dynamic optimisation problems such as (a) maximum conversion (b) maximum productivity (c) maximum profit and (d) minimum time are formulated in this work. Optimal design and or operation policies are obtained for all the reaction schemes. A detailed rigorous dynamic model consisting of mass, energy balances, chemical reaction and thermodynamic properties is considered for the process. The model was incorporated within the dynamic optimisation problems. Control Vector Parameterisation (CVP) technique was used to convert the dynamic optimisation problem into a nonlinear programming problem which was solved using efficient SQP (Successive Quadratic Programming) method available within the gPROMS (general PROcess Modelling System) software. It is observed that multi-reflux ratio or linear reflux operation always led to better performance in terms of conversion, productivity for all reaction schemes compared to that obtained using single reflux operation. Feed dilution (in the case of ethanol esterification) led to more profit even though productivity was found to be lower. This was due to reduction in feed price because of feed dilution. Semi-batch reactive distillation opertation (for ethanol esterification) led to better conversion compared to conventional batch distillation, however, the total amount of acetic acid (reactant) was greater in semi-batch operation. Optimisation of design and operation (for ethanol esterification) clearly showed that a single cloumn will not lead to profitable operation for all possible product demand profile. Also change in feed and /or product price may lead to adjust the production target to maximise the profitability. In batch distillation, total reflux operation is recommended or observed at the begining of the operation (as is the case for methnaol or ethanol esterification). However, in the case of hydrolysis, total reflux operation was obseved at the end of the operation. This was due to lactic acid (being the heaviest) was withrawn as the final bottom product.
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Modelling and optimisation of batch distillation involving esterification and hydrolysis reaction systems. Modelling and optimisation of conventional and unconventional batch distillation process: Application to esterification of methanol and ethanol using acetic acid and hydrolysis of methyl lactate system.Edreder, E.A. January 2010 (has links)
Batch distillation with chemical reaction when takes place in the same unit is referred to
as batch reactive distillation process. The combination reduces the capital and operating
costs considerably. Among many different types of batch reactive distillation column
configurations, (a) conventional (b) inverted (c) semi-batch columns are considered
here.
Three reaction schemes such as (a) esterification of methanol (b) esterification of
ethanol (c) hydrolysis of methyl lactate are studied here. Four different types of
dynamic optimisation problems such as (a) maximum conversion (b) maximum
productivity (c) maximum profit and (d) minimum time are formulated in this work.
Optimal design and or operation policies are obtained for all the reaction schemes.
A detailed rigorous dynamic model consisting of mass, energy balances, chemical
reaction and thermodynamic properties is considered for the process. The model was
incorporated within the dynamic optimisation problems. Control Vector
Parameterisation (CVP) technique was used to convert the dynamic optimisation
problem into a nonlinear programming problem which was solved using efficient SQP
(Successive Quadratic Programming) method available within the gPROMS (general
PROcess Modelling System) software.
It is observed that multi-reflux ratio or linear reflux operation always led to better
performance in terms of conversion, productivity for all reaction schemes compared to
that obtained using single reflux operation.
Feed dilution (in the case of ethanol esterification) led to more profit even though
productivity was found to be lower. This was due to reduction in feed price because of
feed dilution. Semi-batch reactive distillation opertation (for ethanol esterification) led
to better conversion compared to conventional batch distillation, however, the total
amount of acetic acid (reactant) was greater in semi-batch operation. Optimisation of
design and operation (for ethanol esterification) clearly showed that a single cloumn
will not lead to profitable operation for all possible product demand profile. Also
change in feed and /or product price may lead to adjust the production target to
maximise the profitability.
In batch distillation, total reflux operation is recommended or observed at the begining
of the operation (as is the case for methnaol or ethanol esterification). However, in the
case of hydrolysis, total reflux operation was obseved at the end of the operation. This
was due to lactic acid (being the heaviest) was withrawn as the final bottom product. / Libyan Petroleum Institute
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