Abstract
Abstract
 
 Hydrogen, as chain transfer agent, effects on kinetic of propylene polymerization; consequently variation of hydrogen concentration leads to change final product properties and also activates site of used catalyst. This phenomenon is one of the most important process variables is to adjust the final product properties and optimize the operating conditions. This work has attempted to present a mathematical model that cable to calculate the most important indices of end used product, such as melt flow index, number and weight average molecular weight and poly dispersity index. The model can predict profile polymerization rates determining important kinetic parameters such as the activation energy, lumped deactivation reaction initial reaction rate and deactivation constant. The mathematical model was implemented in Matlab/Simulink environment for slurry polymerization in laboratory scale. The modeling approach is based on polymer moment balance method in the slurry semi-batch reactor. In addition, in this work have provided a model that calculating fraction activated sites catalyst via hydrogen concentration. The model was validated by experimental data from lab scale, reactor. The experimental and model outputs were compared; consequently, the errors were within acceptable range.
 KEY WORDS: Mathematical modeling, Propylene polymerization, Kinetics study, Hydrogen response, population balance
 Bull. Chem. Soc. Ethiop. 2018, 32(2), 371-386.
 DOI:https://dx.doi.org/10.4314/bcse.v32i2.15
Highlights
Polypropylene is one of the widest used polyolefin product and its application is strongly affected by the final product properties
Hydrogen was entered to the reactor, propylene was introduced to reactor according to controller program, the reactor was heated up until reach to equilibrium thermodynamic conditions (T = 70 oC, P = 7.5 bar), the reactor was ready to injecting catalyst for starting polymerization
The model has been validated by experimental data (as shown in Figure 2; in the absence of hydrogen concentration with different temperature and Figure 3 at the constant reactor temperature (70 oC) with different hydrogen concentration)
Summary
Polypropylene is one of the widest used polyolefin product and its application is strongly affected by the final product properties. It could be said that the most crucial indices of end used product of polypropylene are comprised of the melt flow index, number average molecular weight, weight average molecular weight, and polydispersity index. These indices depend heavily on independent operational variables such as temperature and hydrogen concentration, as well as the kinetics of polymerization. Hydrogen as a chain transfer agent is one of the most vital affecting factors on the reaction kinetics and final product properties. As reported that hydrogen leads to extra activated sites and yield of the catalyst [1]
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