Optimization of diffusion-controlled free radical polymerizations in a distributed parameter system
Optimization of diffusion-controlled free radical polymerizations in a distributed parameter system
复制标题
分布式参数系统中扩散控制自由基聚合的优化
DOI：
10.1016/0009-2509(89)85073-0
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发表时间：
1989
影响因子：
4.7
通讯作者：
L. J. Lee
中科院分区：
文献类型：
--
作者：
Y. J. Huang;L. J. Lee
本文研究了铸造过程中苯乙烯自由基聚合的开环最优边界控制问题。该体系的特征是一组抛物型偏微分方程组，其中单体转化率、引发剂转化率、死聚合物的力矩和温度(状态变量)都依赖于时间和反应器中的径向位置。目标是寻求最优的壁温，使反应时间或分子量分布(MWD)最小化。采用了考虑凝胶效应和玻璃效应的动力学扩散模型。利用变分方法，可以通过“早期离散化”或“晚期离散化”方法来描述问题。将Min-H技术应用于“早期离散化”方法所建立的问题，以获得最优的壁温分布。对于所研究的系统，发现最优壁面温度分布的变化与相应的集中参数情况下得到的变化非常相似。
This paper deals with open-loop optimal boundary control for free radical polymerizations of styrene in the casting process. The system is characterized by a set of parabolic partial differential equations, where the monomer conversion, initiator conversion, moments of dead polymers, and temperature (state variables) depend on both time and radial position in the reactor. The objective is to seek the optimal wall temperature that will minimize either reaction time or molecular weight distribution (MWD). A kinetic-diffusion model considering the gel effect and the glass effect is used. By using variational methods, the problems can be formulated via either “early discretization” or “late discretization” approach. The Min-H technique is applied to the problems formulated by the “early discretization” approach in obtaining optimal wall temperature profiles. For the system studied, it is found that variations of the optimal wall temperature profiles show great resemblance to those obtained for the corresponding lumped-parameter cases.