Systematic Comparison of Slurry and Gas-Phase Polymerization of Ethylene: Part I Thermodynamic Effects,Macromolecular Reaction Engineering

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Systematic Comparison of Slurry and Gas-Phase Polymerization of Ethylene: Part I Thermodynamic Effects
Macromolecular Reaction Engineering ( IF 1.8 ) Pub Date : 2021-06-19 , DOI: 10.1002/mren.202100006
Arash Alizadeh ₁ , Vasileios Touloupidis ₂ , João B. P. Soares ₁

Affiliation

The Sanchez–Lacombe model is used to investigate the multiphase and multicomponent thermodynamic equilibrium during ethylene polymerization and ethylene/1-hexene copolymerization in slurry and gas-phase reactors. The simulation study focuses on the interactions among ethylene, polyethylene, hydrogen, 1-hexene, and n-hexane under typical polymerization conditions. When used as a diluent, n-hexane increases the concentrations of all reactants in the amorphous polymer phase due to the cosolubility effect. Moreover, n-hexane significantly swells the amorphous polyethylene. This means that a polyethylene particle with the same degree of crystallinity has a larger amorphous phase fraction in slurry than in gas-phase reactors. Consequently, if the gas phase concentration is the same in both modes of polymerization, the concentration of all reactive species in semi-crystalline polyethylene particles will be higher in slurry reactors. The thermodynamic equilibrium simulations agree with the reported experimental results and can explain why supported catalysts behave differently in slurry and gas-phase polymerizations.

中文翻译：

乙烯的淤浆和气相聚合的系统比较：第一部分热力学效应

Sanchez-Lacombe 模型用于研究淤浆和气相反应器中乙烯聚合和乙烯/1-己烯共聚过程中的多相和多组分热力学平衡。模拟研究的重点是，乙烯，聚乙烯，氢，1-己烯的相互作用，和Ñ典型的聚合条件下正己烷。当作为稀释剂使用时，Ñ己烷增加了无定形聚合物相的所有反应物的浓度由于cosolubility效果。此外，n-己烷显着膨胀无定形聚乙烯。这意味着与气相反应器相比，具有相同结晶度的聚乙烯颗粒在淤浆中具有更大的无定形相分数。因此，如果两种聚合模式的气相浓度相同，则半结晶聚乙烯颗粒中所有反应性物质的浓度在淤浆反应器中会更高。热力学平衡模拟与报道的实验结果一致，可以解释为什么负载型催化剂在淤浆和气相聚合中表现不同。

更新日期：2021-06-19

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