苯乙烯聚合反应过程的牌号切换优化策略

Optimal grade transition strategy for a continuous styrene polymerization process

柔性生产模式下的多牌号聚合物生产过程,不仅需要稳态生产中的精确质量控制,也需要建立有效的牌号切换过渡过程运行策略。本文针对单反应器多牌号聚合物生产过程,提出一种以经济优化为目标,基于迭代动态规划的分段式牌号切换操作优化策略,将牌号切换过渡过程划分为动态优化阶段和准稳态过渡阶段。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,构造了一个包含分子量分布参数、反应温度以及引发剂流量等变量的目标函数,利用迭代动态规划求得切换过程中操作变量和产品性能指标的优化轨迹。仿真研究结果表明,本文提出的优化策略能显著缩短切换时间,减少切换过程中单体和引发剂的消耗量。

An effective grade transition policy is essential when several grades of polymers are produced in the same continuous stirred tank reactor( CSTR). In order to minimize operation costs,an optimal two-stage grade transition operation strategy has been developed in this study. In the dynamic optimization stage,the input variable trajectories were calculated by iterative dynamic programming( IDP). The objective function measuring the molecular weight distribution,temperature and initiator flow was formulated to minimize the raw material consumption during the transition operation. Through a case study of free radical styrene polymerization in a pilot CSTR,we show that the proposed operation strategy can shorten the transition time,and also reduce the consumption of monomer and initiator during the grade transition.