Ethylene polymerization process with a highly active Ziegler-Natta catalyst: 2. Molecular weight regulation

Polymer ◽  
1978 ◽  
Vol 19 (5) ◽  
pp. 562-566 ◽  
Author(s):  
L.L Böhm
Keyword(s):  
Molecular Weight ◽  
Ethylene Polymerization ◽  
Polymerization Process ◽  
Weight Regulation ◽  
Highly Active ◽  
Natta Catalyst ◽  
Ziegler Natta Catalyst

scholarly journals Modeling of Ethylene Polymerization with Ziegler-Natta Catalyst in a Bubbling Fluidized Bed Reactor

2021 ◽  
Author(s):  
Neda Felorzabihi
Keyword(s):  
Molecular Weight ◽  
Kinetic Model ◽  
Fluidized Bed ◽  
Ethylene Polymerization ◽  
Fluidized Bed Reactor ◽  
Polymerization Reaction ◽  
Solid Catalyst ◽  
Gas Temperature ◽  
Natta Catalyst ◽  
Ziegler Natta Catalyst

In the present study, a new dynamic fluidized bed reactor (FBR) model is developed to account for the effect of bubble growth in the bed height on the dynamic behaviour of the reactor and the molecular properties of the polymer product. The model takes into account the existence of solid catalyst in both phases and consequently, the occurrence of polymerization reaction in both bubble and emulsion phases. A dynamic two-phase model is employed for predicting the key hydrodynamic parameters of the bed. A comprehensive kinetic model for ethylene polymerization in the presence of multiple-site Ziegler-Natta catalyst is considered to describe the number and molecular weight averages and molecular weight distribution of polymer in the FBR. The hydrodynamic model and the kinetic model have been coupled and solved simultaneously to simulate the performance of the fluidized bed reactor. The study incorporates the effects of the most important reactor parameters such as superficial gas velocity, mean particle size, inlet gas temperature, bubble size, recycle stream and chain transfer agent on the steady-state behaviour of the FBR. The proposed dynamic model is capable of predicting both the performance of the reactor and the polymer physiochemical properties.

scholarly journals Modeling of Ethylene Polymerization with Ziegler-Natta Catalyst in a Bubbling Fluidized Bed Reactor

2021 ◽  
Author(s):  
Neda Felorzabihi
Keyword(s):  
Molecular Weight ◽  
Kinetic Model ◽  
Fluidized Bed ◽  
Ethylene Polymerization ◽  
Fluidized Bed Reactor ◽  
Polymerization Reaction ◽  
Solid Catalyst ◽  
Gas Temperature ◽  
Natta Catalyst ◽  
Ziegler Natta Catalyst

In the present study, a new dynamic fluidized bed reactor (FBR) model is developed to account for the effect of bubble growth in the bed height on the dynamic behaviour of the reactor and the molecular properties of the polymer product. The model takes into account the existence of solid catalyst in both phases and consequently, the occurrence of polymerization reaction in both bubble and emulsion phases. A dynamic two-phase model is employed for predicting the key hydrodynamic parameters of the bed. A comprehensive kinetic model for ethylene polymerization in the presence of multiple-site Ziegler-Natta catalyst is considered to describe the number and molecular weight averages and molecular weight distribution of polymer in the FBR. The hydrodynamic model and the kinetic model have been coupled and solved simultaneously to simulate the performance of the fluidized bed reactor. The study incorporates the effects of the most important reactor parameters such as superficial gas velocity, mean particle size, inlet gas temperature, bubble size, recycle stream and chain transfer agent on the steady-state behaviour of the FBR. The proposed dynamic model is capable of predicting both the performance of the reactor and the polymer physiochemical properties.

Polymerization of ethylene using a high-activity Ziegler–Natta catalyst. II. Molecular weight regulation

1993 ◽  
Vol 31 (1) ◽  
pp. 219-225 ◽  
Author(s):  
Maria M. V. Marques ◽  
Clemente Pedro Nunes ◽  
Peter J. T. Tait ◽  
Alberto Romão Dias
Keyword(s):  
Molecular Weight ◽  
High Activity ◽  
Weight Regulation ◽  
Natta Catalyst ◽  
Ziegler Natta Catalyst

scholarly journals Multiplicity of Active-Site in Heterogeneous Ziegler-Natta Catalyst and Its Correlation with Polymer Microstructure

1970 ◽  
Vol 46 (4) ◽  
pp. 487-494
Author(s):  
ATM Kamrul Hasan
Keyword(s):  
Molecular Weight ◽  
Computer Simulation ◽  
Active Site ◽  
Photoelectron Spectroscopy ◽  
Active Sites ◽  
Chain Structure ◽  
Surface Complexes ◽  
Polymer Microstructure ◽  
Natta Catalyst ◽  
Ziegler Natta Catalyst

Multiplicity of active-site in heterogeneous Ziegler-Natta catalysts and its correlation with polymer microstructure was studied through the surface structure analysis of catalyst by computer simulation of X-ray Photoelectron Spectroscopy (XPS) data and microstructure investigation of polypropylene chains based on the deconvolution of the molecular weight distribution curves by multiple Flory most probable distributions using Gel Permeation Chromatography (GPC) method. The number and relative intensities of these peaks were found correlated to the distribution of multiple active sites. In this investigation, four individual categories of active sites were identified, each of which yields polypropylene with unique properties of molecular weight and chain structure different from other active sites. The reason of the multiplicity of active sites was determined by the presence of different locations of surface titanium species coordinated with other surface atoms or molecules. These different surface complexes of active species determine the multiple active site nature of catalyst which replicates the microtacticity, molecular weight and chain microstructure distribution of polymer. Keywords: Ziegler-Natta catalyst; Multiple active sites; Flory components; Computer simulation; Deconvolution; MWD. DOI: http://dx.doi.org/10.3329/bjsir.v46i4.9596 BJSIR 2011; 46(4): 487-494

Chromium complexes supported by the bidentate PN ligands: synthesis, characterization and application for ethylene polymerization

2018 ◽  
Vol 47 (38) ◽  
pp. 13459-13465 ◽  
Author(s):  
Quande Zheng ◽  
Dejuan Zheng ◽  
Binghao Han ◽  
Shaofeng Liu ◽  
Zhibo Li
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Ethylene Polymerization ◽  
Chromium Complexes ◽  
Highly Active ◽  
Imine Ligands

Chromium complexes bearing phosphine–imine ligands are highly active for ethylene polymerization and produce HDPE with a high molecular weight.

Constructing spherical Ziegler-Natta catalyst through an emulsion process for ethylene polymerization

2019 ◽  
Author(s):  
Zhaoliang Xing ◽  
Chong Zhang ◽  
He Huang ◽  
Hui Liu ◽  
Xiangyu Zhang ◽  
...  
Keyword(s):  
Ethylene Polymerization ◽  
Natta Catalyst ◽  
Emulsion Process ◽  
Ziegler Natta Catalyst

Preparation of Octadecylamine-Graphene/MgCl2-Supported Ziegler-Natta Catalyst and Its Application in Ethylene Polymerization

2018 ◽  
Vol 18 (4) ◽  
pp. 2643-2649
Author(s):  
Hao Zhang ◽  
Jing-Sheng Liu ◽  
He-Xin Zhang ◽  
Eun-Bin Ko ◽  
Jae-Hyeong Park ◽  
...  
Keyword(s):  
Ethylene Polymerization ◽  
Natta Catalyst ◽  
Ziegler Natta Catalyst
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