Friday 3/5/20021 Metallocene Catalyzed Liquid-Pool Polymerization in a Continuous HSR DPI # 114 Mohammad Al-haj Ali DCP\IPP Groups Chemical Engineering Department Quality Assurance of a Polypropylene Reactor During Continuous Production and Product Switch-Over

Friday 3/5/20022 Presentation Outline:  The mechanism of polypropylene polymerization. 1) The catalyst system. 2) Polymerization steps.  Development of expected MWD function. 1) Instantaneous MWD. 2) Derivation of instantaneous MWD function.  Factors affecting MWD. 1) Catalytic System. 2) Polymerization Parameters.

Friday 3/5/20023  Grade transition strategies. 1) Factors affecting grade transition policies. 2) Grade transition approaches. 3) Optimization problem formulation. 4) Objective function. 5) The method of solution.  What is next.

Friday 3/5/20024 Catalyst System: The catalyst system used in this work is: rac-Me 2 Si[Ind] 2 ZrCl 2 /MAO/TIBA 1- Metallocene Catalyst: rac-Me 2 Si[Ind] 2 ZrCl 2

Friday 3/5/20025 Catalyst System: 2- Cocatalysts: a- MAO b- TIBA

Friday 3/5/20026 The Mechanism of Propylene Polymerization: 1- Initiation MCl 2 Me AlO + MMe 2 Me AlO Me AlO - MMe 2 Me M + ++

Friday 3/5/20027 The Mechanism of Propylene Polymerization: 2- Propagation: Me M + R RM + R + M n R M + R

Friday 3/5/20028 The Mechanism of Propylene Polymerization: 2- Propagation:

Friday 3/5/20029 The Mechanism of Propylene Polymerization: 2- Propagation:

Friday 3/5/ The Mechanism of Propylene Polymerization: 3- Termination: a-Transfer with Hydrogen: H2H2 + M n R + + M H n R + b- Transfer with Monomer: + + M n R + n R + M Me

Friday 3/5/ Development of Expected MWD Function: Instantaneous MWD: The method of instantaneous MWD relies on the big difference in time scale for the polymerization reactor and the polymers life time. The instantaneous MWD of polyolefins with single-type catalyst: Schulz-Flory distribution function assumptions: 1- All chain propagating species have the same kinetic parameters. 2- The probability of chain termination does not depend on chain length. 3- polymerization reactions are carried out at constant monomer concentrations.

Friday 3/5/ Development of Expected MWD Function: Derivation of instantaneous MWD function: 1- Propagation reaction 2- Transfer reactions a- transfer with hydrogen: b- transfer with monomer 3- Deactivation

Friday 3/5/ Development of Expected MWD Function: Derivation of instantaneous MWD function The production rate of active and dead polymers:

Friday 3/5/ Development of Expected MWD Function: Derivation of instantaneous MWD function By using QSSA for the active polymer

Friday 3/5/ Development of Expected MWD Function: Derivation of instantaneous MWD function

Friday 3/5/ Development of Expected MWD Function: Derivation of instantaneous MWD function

Friday 3/5/ Factors Affecting MWD: 1- Catalytic System: a- Catalyst type. b- Cocatalyst. c- Catalyst / Cocatalyst 2- Polymerization Parameters: a- Hydrogen concentration. b- Reaction temperature. c- Reaction time.

Friday 3/5/ Factors Affecting MWD: 1- Hydrogen concentration Low H 2 High H 2

Friday 3/5/ Factors Affecting MWD: 1- Reaction temperature Low T High T

Friday 3/5/ Factors Affecting MWD: 1- Reaction time No effect is found for time in MWD: 1- Naofumi & Mizunuma, Chien & Wang, 1990.

Friday 3/5/ Grade transition strategies: Desirable grade transition policy, takes the following points into account:  Time.  Plant safety.  Polymer instantaneous properties.

Friday 3/5/ Requires an extensive trial & error Can not represent PDIConsider all polymer properties

Friday 3/5/ Grade transition strategies: Optimization problem formulation

Friday 3/5/ Grade transition strategies: Objective function

Friday 3/5/ Grade transition strategies: The method of solution Control Vector Parameterization time  ij

Friday 3/5/ Applying U(t) in the original optimization problem gives: Grade transition strategies: The method of solution

Friday 3/5/ What is Next: 1-Formulation of the second optimal strategy for grade transition of 1- Formulation of the second optimal strategy for grade transition of Polyolefins using Barrier Approach. Polyolefins using Barrier Approach. 2- Experimental model validation of the batch mode of the HSR model, and producing bimodal PP theoretically and experimentally. and producing bimodal PP theoretically and experimentally.

Friday 3/5/ Development of Expected MWD Function: Derivation of instantaneous MWD function