Modeling and Simulation of a Multi Phase Semi-batch Reactor
The operation of an industrial semi-batch reactor is modeled and the flow of one reactant
is investigated. In the reactor a strongly exothermic polymerization reaction
takes place followed by a slightly exothermic reaction, and the objective is to minimize
the duration of the operation of the process. Various operational as well as
quality and safety related constraints have to be met during the batch. The complete
process model is derived from measurements, first principles, and reasoning about
effects on molecular level.
This work has been performed in cooperation between Akzo Nobel Functional
Chemicals and Chalmers. We have increased the knowledge of one semi batch process
and tried to improve the production of thickeners by modeling the production
process with the aid of mathematics. A better understanding of the underlying principles
including the chemical reaction heat, energy transfer and the control system
has been gained.
The process model is simulated using MATLAB and SIMULINK. The optimization
is made through investigations of manually chosen EO profiles and simulations.
Piecewise constant EO profiles with up to three constant plateaus and varying
levels have been used. Simulations show that a 5 % increase in total batch time is
possible, using a profile with two plateaus as in the original, but with 20 % higher
levels and no delay.
A 10 % shorter batch time than today is possible using a profile with three different
plateau levels. However, in this a profile, a large portion of the EO is added
prior to the wanted reaction temperature is reached, which may result in a worsened
end product quality. In order to decide which profiles are acceptable, more
research about the effect of the reaction temperature used on the end product quality