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A Prediction Method of Polyolefin Microstructure

A prediction method and technology of microstructure, applied in the field of modeling and simulation of polymerization process, can solve problems such as inability to reflect, achieve the effect of shortening time, simple and clear principle, and improving economic benefits

Active Publication Date: 2018-10-26
EAST CHINA UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] The purpose of the present invention is to overcome the shortcomings of the existing simulation technology and conventional commercial software that only predict the melt index, density and molecular weight distribution, which cannot reflect a kind of important chain structure of polyethylene - the distribution of short branched chains, for the ethylene polymerization process , providing a method for predicting the distribution of short chain branches in polyethylene

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  • A Prediction Method of Polyolefin Microstructure
  • A Prediction Method of Polyolefin Microstructure
  • A Prediction Method of Polyolefin Microstructure

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0074] figure 1 It is a schematic diagram of the modeling method of the present invention; figure 2 It is a schematic diagram of the continuous stirred tank reactor model (CSTR) with two tanks connected in series.

[0075] The object of this example is the production of high-density polyethylene (HDPE) with bimodal distribution by ethylene double-tank series polymerization reactors, and the catalyst is a Ziegler-Natta titanium-based magnesium chloride-supported catalyst, which is operated in a steady state. The operating pressure and operating temperature of the first kettle are 64bar and 95°C respectively, with no comonomer and high hydrogen concentration, and the slurry phase ethylene homopolymerization reaction is carried out. The operating pressure and operating temperature of the second tank are respectively 20 bar and 85° C., with comonomer 1-butene and low hydrogen concentration, to carry out ethylene-1-butene copolymerization reaction. According to the equations in ...

Embodiment 2

[0078] The object of this example is the production of high-density polyethylene (HDPE) with bimodal distribution by ethylene double-tank series polymerization reactors, and the catalyst is a Ziegler-Natta titanium-based magnesium chloride-supported catalyst, which is operated in a steady state. The operating pressure and operating temperature of the first tank are 64 bar and 95°C respectively, with comonomer 1-butene and high hydrogen concentration, and the slurry phase ethylene-1-butene copolymerization reaction is carried out. The operating pressure and operating temperature of the second kettle are respectively 20 bar and 85°C, with no co-monomer and low hydrogen concentration, for ethylene homopolymerization. According to the equation of Table 2 and formulas (1)~(12), first adopt commercialized Polymer Plus calculation software to set up the steady-state model of process, calculate the output of each reactor and the average molecular weight and the average comonomer conten...

Embodiment 3

[0081] The object of this example is high-density polyethylene (HDPE) produced by a single ethylene polymerization reactor, the catalyst is a Ziegler-Natta titanium-based magnesium chloride supported catalyst, and it operates in a steady state. The operating pressure and operating temperature are respectively 19 bar and 80°C, with comonomer and low hydrogen concentration, and the gas phase polymerization reaction of ethylene-1-butene is carried out. According to the equation of Table 2 and formulas (1)~(12), first adopt commercialized Polymer Plus calculation software to set up the steady-state model of process, calculate the output of each reactor and the average molecular weight and the average comonomer content of product; Then, the molecular weight distribution and short-chain branch distribution were calculated by the method of instantaneous distribution. The result is as Figure 5 shown.

[0082] Figure 5 The simulation results show that the prediction method can cal...

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Abstract

The invention discloses a polyolefin microstructure prediction method. Aiming at the polyolefin polymerization process, short branch distribution and molecular weight distribution are utilized as micro mass indexes of polyolefin. A moment method and an instant distribution method are adopted to calculate the average molecular weight, the average co-monomer content, molecular weight distribution and short branch distribution. The method is applicable to various polyolefin production processes, and the intermittent semi-continuous or continuous operation mode can be adopted. Compared with the prior art, the method has the advantages of being capable of predicting polymer short branch distribution and being applied to control and optimization of the polymerization process and design and development of new products.

Description

technical field [0001] The invention belongs to the technical field of modeling and simulation of polymerization processes, and relates to a method for predicting the microstructure of polyolefins, in particular to a method for predicting the distribution of polyethylene short-chain branches. Background technique [0002] Melt index and density are often used as product quality indicators in polyolefin industrial production, but both are very macroscopic properties, which only reflect the average molecular weight of the polymer and the average content of comonomers. Products with the same melt index and density may have very different microscopic molecular structures, and their mechanical properties and processing properties may also vary greatly. The reason is that polyolefins have complex chain structures such as molecular weight distribution, short chain branch distribution, and fine structures such as copolymer composition distribution and sequence distribution. It is t...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G06F17/50
Inventor 钱锋田洲罗娜杜文莉刘柏平
Owner EAST CHINA UNIV OF SCI & TECH