Optimal grade transition and selection of closed-loop controllers in a gas-phase olefin polymerization fluidized bed reactor
Optimal grade transition and selection of closed-loop controllers in a gas-phase olefin polymerization fluidized bed reactor
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DOI：
10.1016/s0009-2509(03)00223-9
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发表时间：
2003-08-01
影响因子：
4.7
通讯作者：
Kiparissides, C
中科院分区：
文献类型：
--
作者：
Chatzidoukas, C;Perkins, JD;Kiparissides, C
为了满足广泛的聚烯烃应用所需的各种产品质量规格，聚合装置被迫在频繁的牌号转换政策下运行。通常，该问题的最佳解决方案是基于使用动态优化方法将根据转换时间、产品质量规格、工艺安全约束和不合格聚合物的量定义的合适的目标函数最小化。然而，考虑到一个给定的控制结构配置可以对过程的可操作性和产品质量优化的巨大影响，时间最优的等级转换问题需要并行解决的控制和操纵变量之间的闭环控制配对的最优选择。在本研究中，混合整数动态优化方法应用于催化气相乙烯-1-丁烯共聚流化床反应器（FBR）的“最佳”的闭环控制配置和时间最优的等级转换策略计算。gPROMS/gOPT的建模和动态优化的计算工具，和GAMS/CPLEX MILP求解器的组合优化问题的解决方案。模拟结果表明，通过应用所提出的综合方法，可以实现显着的质量和经济效益的最佳牌号过渡问题的气相聚烯烃快堆。(C)2003 Elsevier Ltd.保留所有权利。
To satisfy the diverse product quality specifications required by the broad range of polyolefin applications, polymerization plants are forced to operate under frequent grade transition policies. Commonly, the optimal solution to this problem is based on the minimization of a suitable objective function defined in terms of the changeover time, product quality specifications, process safety constraints and the amount of off-spec polymer, using dynamic optimization methods. However, considering the great impact that a given control structure configuration can have on the process operability and product quality optimization, the time optimal grade transition problem needs to be solved in parallel with the optimal selection of the closed-loop control pairings between the controlled and manipulated variables. In the present study, a mixed integer dynamic optimization approach is applied to a catalytic gas-phase ethylene-1-butene copolymerization fluidized bed reactor (FBR) to calculate both the "best" closed-loop control configuration and the time optimal grade transition policies. The gPROMS/gOPT computational tools for modelling and dynamic optimization, and the GAMS/CPLEX MILP solver are employed for the solution of the combined optimization problem. Simulation results are presented showing the significant quality and economic benefits that can be achieved through the application of the proposed integrated approach to the optimal grade transition problem for a gas-phase polyolefin FBR. (C) 2003 Elsevier Ltd. All rights reserved.