Kinetic Analysis and Optimization for the Catalytic Esterification Step of PPT Polymerization

Abstract

Summary: A well‐validated kinetic scheme has been studied for PPT, poly(propylene terephthalate) polymerization process in batch and semi‐batch mode with tetrabutoxytitanium (TBOT), a proven catalyst. Optimization study and analysis for PPT are rare, as the industrial relevance of PPT just became vibrant due to the commercial availability of one of its monomers in industrial scale in the recent past. Correctness of the analysis is checked by a new approach and parameters for the model are estimated from available experimental data. Solubility of terephthalic acid (TPA) is less in reaction medium and this effect is also considered along with the reaction scheme. Several simulations have been performed to see various process dynamics and this ultimately helps in formulating optimization problems. Using recently developed and well tested real‐coded non‐dominated sorting genetic algorithm‐II, a state‐of‐the art evolutionary optimization algorithm, a couple of three objective optimization problems have been solved and corresponding Pareto sets are presented. Results show remarkably promising aspects of productivity enhancement with an improvement in product quality. Sensitivity analysis for relatively uncertain solubility parameter is also performed to estimate its effect over the proposed optimal solutions.Multiobjective Pareto front for 3 objectives: degree of polymerization, time and (bTPA + bPG).imageMultiobjective Pareto front for 3 objectives: degree of polymerization, time and (bTPA + bPG).

Selection of Catalyst for the Esterification Step of the PPT Polymerization Process

“…Karayannidis et al1 used a functional group approach to develop a batch process model (a system of highly non‐linear coupled ordinary differential equations ‐ initial value problem (ODE‐IVP)) based on the kinetic scheme (Scheme ). Majumdar et al6 have converted those batch process equations to semi‐batch process equations with timely modification of process parameters (various reactant concentrations) while simulating intermediate addition of monomers in the reactor. Also some modifications were made for water generation and removal methodology.…”

“…Some logic is used to memorize the total amount of vaporized water to calculate the final conversion of TPA, which is based on water formation. In the semi‐batch mode of analysis, updating the parameters like the solid and liquid part of TPA requires a lot of attention, which otherwise leads to some erroneous facts (Majumdar et al6). For detailed process and modeling issues, one may refer to Karayannidis et al1 and Majumdar et al6…”

“…Comparable research work has been done by Kang et al2 for PET polymerization with functional group analysis. Other important research works that have been utilized in this present study are the works of Yamada3 (solubility of TPA in ethylene glycol), Padias and Hall4 (solubility of TPA in butanediol), Rieckmann and Volker5 (corrections to the kinetic rate constants for acid catalyzed esterification and polycondensation reactions) and Majumdar et al6 (use of a functional group approach to optimize the performance of the esterification step of PPT polymerization with respect to TBOT catalyst).…”

“…An optimization study by Majumdar et al6 took a critical look inside the PPT system to reveal some unknown process dynamics that are very difficult to unveil otherwise. All of this effort was supposed to minimize the gap between the mathematical analysis of a process with its actual plant realizations.…”

Simulation and Optimization of Wiped-Film Poly-Ethylene Terephthalate (PET) Reactor Using Multiobjective Differential Evolution (MODE)

“…Pareto sets of nondominated solutions are generated in all cases. Several researchers extended their study in the filed of polymer development [18][19][20][21][22][23][24][25].…”