Effect of monomer feed and production rate on the control of molecular weight distribution of polyethylene in gas phase reactors
Effect of monomer feed and production rate on the control of molecular weight distribution of polyethylene in gas phase reactors
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DOI：
10.1016/j.compchemeng.2011.04.014
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发表时间：
2011-11-15
影响因子：
4.3
通讯作者：
Ali, Emad M.
中科院分区：
文献类型：
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作者：
Ali, Mohammad Al-haj;Ali, Emad M.
研究了通过改变流化床反应器中单体与氢的摩尔比来控制聚合物分子量分布的方法。采用非线性模型预测控制器通过控制单体和氢气进料速率来改变摩尔比。模拟结果显示了有希望的结果，但是同时利用单体和氢流和氢流之间存在权衡。使用单体和氢气流有利于快速过渡到所需的随钻速度，但代价是更高的吹扫和不稳定的产量。采用专用进氢装置，生产速度稳定，吹扫消耗少。然而，需要更长的时间才能达到期望的MWD。采用离散的产品退出机制时，也观察到同样的现象。(C) 2011 Elsevier Ltd.版权所有。
The control of the polymer molecular weight distribution via altering the monomer to hydrogen molar ratio in fluidized bed reactors is examined. The molar ratio is altered by manipulating the monomer and hydrogen feed rates using nonlinear model predictive controller. The simulation revealed promising results however a trade-off between utilizing both the monomer and hydrogen flows simultaneously and the hydrogen flow exclusively exists. Utilization of the monomer and hydrogen flows together favors the rapid transition to the required MWD but at the expense of higher purge and inconsistent production rate. Exclusive use of the hydrogen intake leads to steady production rate and less consumption of the purge. However, longer time is needed to achieve the desired MWD. The same phenomena are observed when discrete mechanism for product withdrawal is implemented. (C) 2011 Elsevier Ltd. All rights reserved.