Abstract: For the on-line optimization of complex，large-scale chemical process systems，because optimization time may be too long or optimal solution cannot be obtained，the method of subsystem coordinating optimization can be an approach to solving the above problem.But interrelated variables of coordinating optimization may have different directions for a better solution.A coordinating optimization based on interrelated variables alternation is proposed.The subsystems are optimized based on alternation，and multi-problems of every subsystem optimization are solved by optimizing interrelated variables without changing independent variables or optimizing independent variables without changing interrelated variables.The alternation of subsystems is an iterative process until the condition of ending is satisfied.The proposed method is used in the optimization of simulated FCCU(fluid catalytic cracking unit).The solution is compared with the whole optimal solution，which shows the effectiveness of the proposed method.At last，the solution of on-line optimization with the proposed method shows its feasibility for chemical process on-line optimization.

Key words: on-line optimization, coordination, interrelated variables, alternation

摘要： 化工过程复杂大系统的在线优化过程中，存在流程前后的关联导致优化时间过长或得不到优化解的问题，需要按子系统优化并协调的优化方法来解决，而协调优化方法存在关联变量寻优方向不一致的问题。提出了一种基于子系统间关联变量轮换思想的分解协调优化方法，对大系统分解得到的子系统以轮换的方式进行优化，子系统中包含的多个优化问题分别在固定关联变量优化独立变量和固定独立变量优化关联变量的条件下求解，此轮换过程迭代进行，直至满足优化终止条件。将提出的方法应用在催化裂化装置仿真实例中与整体优化方法的结果作比较，证明了方法的有效性。最后，将基于关联变量轮换的协调优化方法应用在化工过程的在线优化中，结果表明本方法在在线优化应用中是可行的。

关键词: 在线优化, 协调, 关联变量, 轮换