Modelling of Chemical Reaction Systems
Modelling of Chemical Reaction Systems

Author: K.H. Ebert

Publisher: Springer Science & Business Media

Published: 2012-12-06

Total Pages: 399

ISBN-13: 3642682200

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For rather a long time numerical results in chemical kinetics could only be obtained for very simple chemical reactions, most of which were of minor practi ca 1 importance. The avail abil ity of fast computers has provi ded new opportunities for developments in chemical kinetics. Chemical systems of practical interest are usually very complicated. They consi st of a great number of different el ementary chemi cal reacti ons, mostly with rate constants differi ng by many orders of magni tude, frequently with surface reacti on steps and often wi th transport processes. The deri vati on of a 'true' chemical mechani sm can be extremely cumbersome. Mostly this work is done by setting up 'reaction models' which are im proved step by step in comparison with precise experimental data. At this early stage mathematics is involved, which may al ready be rather complicated. Mathematical methods such as pertubation theory, graph theory, sensitivity analysis or numerical integration are necessary for the derivation and application of optimal chemical reaction models. Most theoretical work aimed at improving the mathematical methods was done on chemical reactions which mostly were of little practical im portance. Chemi cal engi neers, who evi dently k now well how important the chemical model s and their dynamics are for reactor desi gn, have al so to be convinced not only on the theoretical work but also on its practical applic abil ity.

Optimization of Emulsion Polymerization of Styrene and Methyl Methacrylate (MMA)
Optimization of Emulsion Polymerization of Styrene and Methyl Methacrylate (MMA)

Author: Kam Yok Loke

Publisher:

Published: 2013

Total Pages: 67

ISBN-13:

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This paper studies the optimization of emulsion copolymerization of Styrene and Methyl Methacrylate (MMA). A model-based framework for optimal operation of copolymerization processes was used in gPROMS environment and enables us to predict the maximum monomer conversion for a given total monomer feed over the batch time. The complexities of the process were represented by mathematical models for optimization and control. A process model involving the equations for mass and energy balance describing the particle evolution in a batch reactor and diffusion controlled kinetics is incorporated into the optimization framework. The modeling is account for complex physic-chemical sub-processes involving particle formation mechanisms with two monomer droplets, surfactants, initiator and particulates. Using gPROMS, the system analyzed the data, created models, developed algorithms, manipulated and plotted based on the functions and data. The determination of optimal profile for control variables used for emulsion polymerization of styrene and MMA that yielded desired conversion with fixed batch time and fixed number average molecular weight in batch reactor respectively were carried out in batch reactor. Reduction of the pre-batch time increases the Mn but decreases the conversion (Xn). The faster the addition of monomer into the reactor, the earlier the growth of the polymer chain leading to higher Mn. The increases of the reaction temperature will decrease the Mn since increases of temperature will increase the rate of termination reaction.