CAJ | 학술논문

在模块环境(Aspen Plus)下,建立了基于多目标遗传算法NSGA-Ⅱ求解多目标优化问题的系统结构,并对含循环物流的连续过程废料最小化问题进行求解.在求解过程中遗传算法需要反复调用流程模拟,而流程中循环物流的迭代收敛使优化计算效率较低.为减少流程迭代次数本文提出2个加速策略:一是变收敛精度策略,在优化计算初始阶段,使流程在较低精度下收敛,快速淘汰劣点,随着优化的进行,将流程收敛精度逐步提高,得到高质量的非劣解;二是循环流初值策略,利用已有的计算值,回归决策变量与循环流变量的对应关系,改善循环流初值.实例结果表明,加速策略减少了一半左右的流程迭代次数,效率提高50%,本文提出的求解多目标问题的方法能方便地得到问题的Pareto最优解集,可应用于一般连续化工过程的多目标优化.
재모괴배경(Aspen Plus)하,건립료기우다목표유전산법NSGA-Ⅱ구해다목표우화문제적계통결구,병대함순배물류적련속과정폐료최소화문제진행구해.재구해과정중유전산법수요반복조용류정모의,이류정중순배물류적질대수렴사우화계산효솔교저.위감소류정질대차수본문제출2개가속책략:일시변수렴정도책략,재우화계산초시계단,사류정재교저정도하수렴,쾌속도태렬점,수착우화적진행,장류정수렴정도축보제고,득도고질량적비렬해;이시순배류초치책략,이용이유적계산치,회귀결책변량여순배류변량적대응관계,개선순배류초치.실례결과표명,가속책략감소료일반좌우적류정질대차수,효솔제고50%,본문제출적구해다목표문제적방법능방편지득도문제적Pareto최우해집,가응용우일반련속화공과정적다목표우화.
A framework based on NSGA-II in modular environment(Aspen Plus)is proposed and a waste minimization problem of acontinuous process which contains recycle is solved on this platform.MOGA needs to spend lots of computer time to simulate flowsheet,especially when the flowsheet contains recycle.For reducing iteration number of simulation,we propose two strategies:one is changingtolerance strategy,that at initial stage of optimization the convergence tolerance of recycle is lower in order to get rid of inferior solutionquickly,then the tolerance is higher graduaUy in order to get better non-inferior solution set,the other strategy is improved initial recy-cle strategy,that the initial value of recycle is calculated by a correlation which is acquiredfrom the initial flowsheet simulation.Resultsshowed that the number of iteration is reduced about a half.The method in this paper can attain the Pareto front ofthe problem and thefranlcwork can be easily used to optimize other continuous processes.