基于改进同步策略的PE多牌号切换优化

大型PE生产中,同一装置往往承担着不同牌号的生产任务,且牌号生产过程具有典型非线性,传统操作模式下牌号切换过渡过程较长,产品质量不稳定。同步策略算法是解决大规模复杂非线性优化问题的有效方法,然而常规同步策略算法没有规定微分变量在有限元端点处的可导性。提出了一种改进的同步策略算法,通过对微分状态变量在有限元端点处施加导数约束,提高了算法的求解性能;其次,对于NLP问题,采用罚函数自由的非单调线搜索内点SQP算法,避免了罚函数及罚因子的选取对最优结果的影响。此外,在牌号切换目标函数中引入了路径约束和露点温度等冷凝操作约束,实例证实了该方法的快速稳定性和求解准确性。

PE Multi-grade Transition Optimization Based on the Improved Simultaneous Strategies

The same plant often produces different grade products in a large PE process,and the production process is typical nonlinear.The time is long and the product quality is unstable during different grades transition under traditional operation mode.Simultaneous strategies algorithm is an effective way to solve this large scale complicated nonlinear optimization problem.Traditional simultaneous strategies don’t regulate the conductivity of differential variables in finite element endpoint.An improved simultaneous algorithm is approached,the performance of this algorithm has been improved through introducing into derivative restrictions in finite element endpoint;Secondly,for NLP,the penalty function free nonmonotone line search interior point SQP algorithm is adopted to avoid the selection of penalty function and factor to affect the optimal results.In addition,path constraints and dew point temperature and other condensing operation constraints are contained in objective function.It has been proved that the proposed method is of stability and effectiveness.