30 research outputs found
Recommended from our members
Comparison of Conventional and Middle Vessel Batch Reactive Distillation Column: Application to Hydrolysis of Methyl Lactate to Lactic Acid
NoComparison of optimal operation between conventional batch reactive distillation column (CBRD) and middle-vessel batch reactive column (MVBRD) for the production of lactic acid via hydrolysis of methyl lactate has not been considered in the past. Therefore, it is the main focus in this work. A dynamic optimization problem incorporating a process model is formulated to minimize the batch time subject to constraints on the amount and purity of lactic acid. Control variables (reflux ratio or/and a reboil ratio) are treated as a piecewise constant. Optimization results indicate that MVBRD is more effective than CBRD in terms of saving in batch time which can be as high as of 20 %
Recommended from our members
Optimal Operation of Batch Reactive Distillation Process Involving Esterification Reaction System
NoThe performance of batch reactive distillation process involving the esterification of acetic acid with methanol to produce methyl acetate and water is considered in this work. Two cases studies with varying amount of the reactants are considered. The reflux ratio (single time interval) is selected as the control variable to be optimised (treated as piecewise constant) for different but fixed batch time ranging from 5 to 15 h, so as to maximise the conversion of methanol subject to product purity of methyl acetate. The dynamic optimisation problem is converted to a nonlinear programming problem by Control Vector Parameterization (CVP) technique and is solved by using efficient SQP method. The optimisation results show that as the methanol and methyl acetate are wide boiling, the separation of methyl acetate is easier without losing much of methanol reactant. The conversion improves by 6.4 % due to sufficient amount of acetic acid being reacted with methanol. Moreover an excess of acetic acid leads to high operation temperature and therefore high reflux operation (to reduce loss of methanol from the top of the column) to maximise the conversion
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
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.EThOS - Electronic Theses Online ServiceLibyan Petroleum InstituteGBUnited Kingdo
Comparison of Conventional and Middle Vessel Batch Reactive Distillation Column: Application to Hydrolysis of Methyl Lactate to Lactic Acid
NoComparison of optimal operation between conventional batch reactive distillation column (CBRD) and middle-vessel batch reactive column (MVBRD) for the production of lactic acid via hydrolysis of methyl lactate has not been considered in the past. Therefore, it is the main focus in this work. A dynamic optimization problem incorporating a process model is formulated to minimize the batch time subject to constraints on the amount and purity of lactic acid. Control variables (reflux ratio or/and a reboil ratio) are treated as a piecewise constant. Optimization results indicate that MVBRD is more effective than CBRD in terms of saving in batch time which can be as high as of 20 %