Simulation of an Industrial Linear Low Density Polyethylene Plant

2011 ◽  
Vol 6 (1) ◽  
Author(s):  
Ali Farhangiyan Kashani ◽  
Hossein Abedini ◽  
Mohammad Reza Kalaee
Keyword(s):  
Steady State ◽  
Average Molecular Weight ◽  
Molar Fraction ◽  
Operating Conditions ◽  
Low Density Polyethylene ◽  
Process Equipment ◽  
Flow Index ◽  
Low Density ◽  
Linear Low Density Polyethylene ◽  
Wide Range

In this paper, an industrial linear low density polyethylene (LLDPE) production process including two serried fluidized bed reactors (FBR) and other process equipment was completely simulated in steady state mode. Both of FBRs were considered like two serried continuous stirred tank reactors (CSTR). In this simulation, a kinetic model that is based on a multiple active site heterogeneous Ziegler-Natta catalyst was used for simulation of reactions in two FBRs. Simulator by using this model is able to predict the important attributes of LLDPE like melt flow index (MFI), density (ρ), polydispersity (PDI), numerical and weight average molecular weight (Mn, Mw) and co-polymer molar fraction (SFRAC). On the other hand, this simulator can be applied in wide range of changing in inlet operating conditions. The results of the simulation are compared with industrial data of LLDPE plant. A good agreement is observed between the simulator predictions and actual plant data. Finally, by using of the simulator, the steady state operating conditions for producing different grades of polyethylene are obtained.

A Comparison of Rheological Models and Experimental Data of Metallocene Linear Low Density Polyethylene Solutions as a Function of Temperature and Concentration

2016 ◽  
Vol 12 (3) ◽  
pp. 4322-4339
Author(s):  
Salah Hamza
Keyword(s):  
Experimental Data ◽  
Shear Rate ◽  
Rheological Properties ◽  
Power Law ◽  
Low Density Polyethylene ◽  
Effect Of Temperature ◽  
Low Density ◽  
Linear Low Density Polyethylene ◽  
Shear Rates ◽  
Wide Range

Knowledge of rheological properties of polymer and their variation with temperature and concentration have been globally important for processing and fabrication of polymers in order to make useful products. Basheer et al. [1] investigated, experimentally, the changes in rheological properties of metallocene linear low density polyethylene (mLLDPE) solutions by using a rotational rheometer model AR-G2 with parallel plate geometry. Their work covered the temperature range from  to  and  concentration from  to . In this paper, we reconsider Basheer work to describe the rheological behavior of mLLDPE solutions and its dependence on concentration and temperature.Until now, several models have been built to describe the complex behavior of polymer fluids with varying degrees of success. In this article, Oldroyd 4-constant, Giesekus and Power law models were tested for investigating the viscosity of mLLDPE solution as a function of shear rate. Results showed that Giesekus and power law models provide the best prediction of viscosity for a wide range of shear rates at constant temperature and concentration. Therefore, Giesekus and power law models were suitable for all mLLDPE solutions while Oldroyd 4-constant model doesn't.A new proposed correlation for the viscosity of mLLDPE solutions as a function of shear rate, temperature and concentration has been suggested. The effect of temperature and concentration can be adequately described by an Arrhenius-type and exponential function respectively. The proposed correlation form was found to fit the experimental data adequately.

An experimental study on foaming of linear low-density polyethylene/high-density polyethylene blends

2016 ◽  
Vol 53 (1) ◽  
pp. 83-105 ◽  
Author(s):  
Peyman Shahi ◽  
Amir Hossein Behravesh ◽  
Ali Haghtalab ◽  
Ghaus Rizvi ◽  
Fatemeh Goharpei
Keyword(s):  
Bulk Density ◽  
High Density Polyethylene ◽  
Cell Structure ◽  
High Density ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Linear Low Density Polyethylene ◽  
Polyethylene Blends ◽  
Wide Range ◽  
Foaming Behavior

In this research work, foaming behavior of selected polyethylene blends was studied in a solid-state batch process, using CO2 as the blowing agent. Special emphasis was paid towards finding a relationship between foamability and thermal and rheological properties of blends. Pure high-density polyethylene, linear low-density polyethylene, and their blends with two weight fraction levels of high-density polyethylene (10 and 25%wt.) were examined. The dry blended batches were mixed using an internal mixer in a molten state, and then the disk-shaped specimens, 1.8 mm in thickness, were produced for foaming purposes. The foaming step was conducted over a wide range of temperatures (120–170℃), and the overall expansion and cellular morphology were evaluated via density measurements and captured SEM micrographs, respectively. Three-dimensional structural images were also captured using a high resolution X-ray micro CT for different foamed samples and were compared. Rheological and DSC tests for the virgin and blends were also performed to seek for a possible correlation with the formability. Based on the results, blended polyethylene foams exhibited remarkable expansion and highly enhanced cell structure compared to pure polymers. Bulk density, as low as 0.33 g/cm3, was obtained for blends, while for the virgin high-density polyethylene  and linear low-density polyethylene, bulk density lower than 0.5 g/cm3 was not attainable. The lowest density was observed at a foaming temperature of 10–20℃ above the melting (peak) temperature obtained via DSC test. Rheological characteristics, including storage modulus and cross-over frequency value, were also found to be the indicators for the materials foaming behavior. Moreover, blends with 25% wt. of high-density polyethylene exhibited the highest expansion values over a wider range of temperature compared with 90% linear low-density polyethylene/10% high-density polyethylene.

Hemp Fibers Waste and Linear Low Density Polyethylene Composite Properties

2016 ◽  
Vol 721 ◽  
pp. 33-37
Author(s):  
Zane Zelca ◽  
Silvija Kukle ◽  
Janis Kajaks ◽  
Marija Geikina-Geimana
Keyword(s):  
Water Resistance ◽  
Melt Flow Index ◽  
Lubricant Additive ◽  
Low Density Polyethylene ◽  
Flow Index ◽  
Low Density ◽  
Linear Low Density Polyethylene ◽  
Melt Flow ◽  
Hemp Fibers ◽  
Polyethylene Composite

Influence of the composite preparing technology and filler type (hemp waste and hemp fibres) on the performance characteristics (melt flow index and water resistance) of the composites based on a linear low density polyethylene (LLDPE) was investigated. The best melt flow index (MFI) results were achieved when as composites preparing method extrusion and two rolls mill with lubricant additive combination were used. It is established that usage of extrusion mixing method of the hemp fibers containing LLDPE composites significantly affects materials melts fluidity evaluated by values of MFI and quality of extruded profile. The lowest fluidity was observed for composite with hemp waste prepared by two rolls mill processing method. The best water resistance was observed for composites with lubricant and for their preparing two rolls mill and extrusion processing methods combination was used.

Phase inversion and co-continuity domain in immiscible polyethylene/polystyrene blends

e-Polymers ◽  
2003 ◽  
Vol 3 (1) ◽  
Author(s):  
Frédéric Prochazka ◽  
Romulus Dima ◽  
Jean-Charles Majesté ◽  
Christian Carrot
Keyword(s):  
Electron Microscopy ◽  
Phase Inversion ◽  
Single Point ◽  
Selective Extraction ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Linear Low Density Polyethylene ◽  
Wide Range ◽  
Internal Mixer ◽  
Scanning Electron

Abstract Blends of polystyrene and high-density or linear low-density polyethylene have been prepared in an internal mixer and studied in a wide range of compositions. Phase inversion compositions have been determined using selective extraction and scanning electron microscopy. It appears that phase inversion can occur in a domain of compositions rather than at a single point. The existing models of phase inversion are not complete enough to explain the entire phenomenon, and percolation of each component may be considered to describe the formation of co-continuity.

Investigation the Phase Separation in Metallocene Linear Low Density Polyethylene/Polypropylene Blends

2020 ◽  
Vol 1159 ◽  
pp. 1-18
Author(s):  
Haia Aldosari
Keyword(s):  
Melt Flow Index ◽  
Melting Behavior ◽  
Low Density Polyethylene ◽  
Flow Index ◽  
Low Density ◽  
Linear Low Density Polyethylene ◽  
Binary Blend ◽  
X Ray ◽  
The Stability ◽  
Polypropylene Blends

The present study is aimed at investigated the miscibility in binary blend the Metallocene linear low density polyethylene (PE) and the Polypropylene homo (PP). Metallocene linear low density polyethylene is one of LLDPEs but with lower density higher melt flow index (MFI) than conventional LLDPE. The polyethylene and polypropylene blends (PB) were prepare by using o-xylene as solvent and polyethylene-co-glycidyl methacrylate (PE-co-GMA) as compatibilizer promote blending of immiscible homopolymers and the stability of the blend . The composites were characterized by wide angle X-ray diffraction (WAXD). Long period spacing was obtained using small angle X-ray scattering (SAXS).Crystallinity and melting behavior were studying by use the DSC and TGA, Metallocene linear low density polyethylene provide better behavior than the conventional LLDPE. The tensile test and DMA test were applied on the blends, which displayed improvement on the blend properties by using the PE-co-GMA and confirm the incompatible nature of the blends.

Optimization studies of low-density polyethylene process: effect of different interval numbers

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Ashraf Azmi ◽  
Suhairi Abdul Sata ◽  
Fakhrony Sholahudin Rohman ◽  
Norashid Aziz
Keyword(s):  
Dynamic Optimization ◽  
Monomer Conversion ◽  
Polymerization Process ◽  
Low Density Polyethylene ◽  
Quadratic Program ◽  
Flow Index ◽  
Low Density ◽  
Orthogonal Collocation ◽  
Interval Numbers ◽  
Optimization Study

AbstractThe highly exothermic nature of the low-density polyethylene (LDPE) polymerization process and the heating-cooling prerequisite in tubular reactor can lead to various problems particularly safety and economic. These issues complicate the monomer conversion maximization approaches. Consequently, the dynamic optimization study to obtain maximum conversion of the LDPE is carried out. A mathematical model has been developed and validated using industrial data. In the dynamic optimization study, maximum monomer conversion (XM) is considered as the objective function, whereas the constraint and bound consists of maximum reaction temperature and product melt flow index (MFI). The orthogonal collocation (OC) on finite elements is used to convert the original optimization problems into Nonlinear Programming (NLP) problems, which are then solved using sequential quadratic program (SQP) methods. The result shows that five interval numbers produce better optimization result compared to one and two intervals.

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