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Olefin polymerization method

A technology for olefin polymerization and aromatic hydrocarbons, applied in the field of olefin polymerization, can solve the problems of narrow molecular weight distribution, increased production cost, poor processing performance, etc., and achieves the effects of wide molecular weight distribution, improved production capacity and high bulk density

Active Publication Date: 2015-05-27
PETROCHINA CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] Catalyst research and development is the core of production technology in the olefin polymerization production process. In the past, when the slurry method and the gas phase method were used to produce polyolefin products, the catalyst used was mainly Ti / Mg carrier type Z-N catalyst. The molecular weight distribution of polyolefin products produced by this catalyst (MWD) is relatively narrow, and when producing higher molecular weight polyolefin products, the processability of the product is poor. If you want to obtain polyolefin products with high molecular weight and wide molecular weight distribution, you need to adopt a double reactor process or a composite catalyst system. It has caused problems such as increased difficulty in production process control and increased production costs.
In addition, the use of Ti / Mg carrier type Z-N catalyst system, the bulk density of the polymerization product is relatively low, which limits the improvement of the production capacity of the device
[0003] There are following three methods for preparing polyolefin products with wide molecular weight distribution: (1) blending of two kinds of polymers. This method is not only costly, but also difficult to achieve complete and uniform blending of the resin, which affects the performance of the product; (2) ) Through segmental polymerization in a graded reactor, uniform mixing in the reactor can be realized, and the operation adjustment flexibility is large, but the production efficiency is low and the production cost is high; (3) Bimetallic or multimetallic active component catalysts are used in a single reactor , using their respective different polymerization behaviors to directly produce wide molecular weight distribution polyethylene products in a single reactor. In theory, this method is the most desirable, but in practice it is difficult to integrate multiple polymerization behaviors into one

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] The polymerization reaction was carried out on a 2L slurry method polymerization evaluation apparatus. The 2L polymerization kettle was purged with nitrogen, 1000mL of hexane was added, stirring was started, and 4mmol of triisobutylaluminum cocatalyst hexane solution was added at the same time, the polymerization kettle control program was started, and the temperature was raised. When the temperature of the reaction system rises to 78°C, add 0.05MPa of hydrogen and 37mg of vanadium-containing compound (VMg nAl, n is 0.9), and when the polymerization temperature reaches 80°C, start to feed ethylene to the reaction pressure of 0.74MPa to carry out the polymerization reaction . After 2 hours of reaction time, stop passing through ethylene, start to lower the temperature, release the pressure and discharge the material, dry the product, and the polymerization activity reaches 1.6×10 7 gPE (molV h) -1 , polymer bulk density 0.38g / cm 3 , the molecular weight distribution o...

Embodiment 2

[0028] Change the hexane solution addition amount of triisobutylaluminum cocatalyst to be 2mmol, other operating conditions are identical with embodiment 1, polymerization activity reaches 0.5 * 10 7 gPE (molV h) -1 , polymer bulk density 0.38g / cm 3 , the molecular weight distribution of the polymer is 18, and the weight average molecular weight of the polymer is 320,000.

Embodiment 3

[0030]Change the hexane solution addition amount of triisobutylaluminum cocatalyst to be 6mmol, other operating conditions are identical with embodiment 1, polymerization activity reaches 2.1 * 10 7 gPE (molV h) -1 , polymer bulk density 0.40g / cm 3 , the molecular weight distribution of the polymer is 22, and the weight average molecular weight of the polymer is 510,000.

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Abstract

The invention relates to an olefin polymerization method. A compound containing vanadium is used as a primary catalyst and an organic compound of aluminum is used as an auxiliary catalyst. When olefin is polymerized, the mole ratio of the aluminum in the auxiliary catalyst to the vanadium in the primary catalyst is 10-10000:1. The constitutional formula of the compound containing the vanadium is VMg.nAl, wherein Mg.nAl is a magnesium and aluminum composite carrier and n ranges from 0.1 to 10. The polymerization temperature ranges from 70 DEG C to 110 DEG C, the pressure ranges from 0.7 MPa to 2.5 MPa, hydrogen is used as a molecular weight modifier, the reaction time is 2 hours to 4 hours, propylene is used as a monomer, other monoene or polyenoid is used as a comonomer, and a single reactor slurry process and a vapor phase method process are adopted. The olefin polymerization method is particularly suitable for the production of olefin products high in molecular weight and wide in molecular weight distribution. The polymers are regular spherical particles, and no fine powder or low polymers exist in the polymerization products. By means of measurement of a gel permeation chromatography (GPC) apparatus, the weight-average molecular weight of the polymer is larger than 350 thousand and the width of the molecular weight distribution is larger than 15.

Description

technical field [0001] The invention relates to a method for olefin polymerization, which uses a vanadium-containing catalyst system to catalyze olefin polymerization to produce polyolefin products with different molecular weights and molecular weight distribution widths. Background technique [0002] Catalyst research and development is the core of production technology in the olefin polymerization production process. In the past, when the slurry method and the gas phase method were used to produce polyolefin products, the catalyst used was mainly Ti / Mg carrier type Z-N catalyst. The molecular weight distribution of polyolefin products produced by this catalyst (MWD) is relatively narrow, and when producing higher molecular weight polyolefin products, the processability of the product is poor. If you want to obtain polyolefin products with high molecular weight and wide molecular weight distribution, you need to adopt a double reactor process or a composite catalyst system. ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08F10/02C08F10/06C08F210/16C08F210/02C08F210/06C08F4/68C08F4/02
Inventor 郎笑梅赵成才杨忠华张丽洋任鹤付义邹恩广马丽于占元赵增辉王立娟姜进宪张瑀健岳远航
Owner PETROCHINA CO LTD