Abstract:

In this work, an optimal grade transition strategy based on the combination of regulatory control and dynamic optimization for a continuous multi-grades polymerization process was proposed. The optimal grade transition of a continuous stirred tank reactor (CSTR) to minimize consumption of raw materials during transition operation was discussed, and the optimal trajectories of the reaction conditions and polymer quality are calculated using iterative dynamic programming. The path constraints on the reaction temperature change was introduced to alleviate the fluctuations during grade transition, and to obtain an easily tracked optimal trajectory as well. Through case study of a free radical styrene polymerization in a pilot CSTR, it is shown that the grade transition strategy can shorten the transition time and minimize the material consumption, and overcome the disturbance of feed temperature as well.

Key words: grade transition, iterative dynamic programming, continuous stirred tank reactor (CSTR), styrene polymerization

摘要：

针对单反应器多牌号聚合物生产过程, 提出一种结合动态优化和反馈控制的牌号切换策略。以实验室规模的连续搅拌釜式反应器中苯乙烯聚合牌号切换为对象, 以原料消耗最少为优化目标, 利用迭代动态规划求得切换过程中反应条件和产品性能指标的优化轨迹。引入针对反应温度的路径约束, 使优化后的切换轨迹更易跟踪实现, 防止过渡过程中变量的剧烈波动。仿真结果表明, 这一切换策略可以显著减少牌号切换过渡时间及过渡过程中原料的消耗量, 并能够有效克服进料温度变化的干扰。

关键词: 牌号切换, 迭代动态规划, 连续搅拌釜式反应器, 苯乙烯聚合