Abstract: Because of the large scale feature of the rigorous model,process optimization on multi-stage columns could be difficult to converge.In this paper,a reduced-order model based on the group method is proposed for high purity distillation columns which correlates the component recoveries with absorption factors and number of theoretical stages.Considering the strongly nonlinear characteristics of absorption factor along the column of high purity distillation column,a piecewise linear fitting method is proposed to obtain the component recoveries.Simulations are conducted under different loads to compare the performance of the reduced-order model and the rigorous model.The results show that the model scale is dramatically decreased from 2377 variables in the rigorous model to 34 variables in the proposed reduced-order model,the convergence time is also greatly reduced from 6136 s to that around 1 s,but the model accuracy is not damaged with very small errors between these two models.

Key words: air separation, high purity distillation column, reduced-order model, aggregated model

摘要： 多级汽液平衡过程的严格模型变量维数高,用于构建优化命题时不易收敛且计算速度较慢。采用集合算法中基于吸收因子和理论塔板数计算全塔段组分回收率的组分分配特征方程代替逐板相平衡,加入物料衡算等基本方程与若干简化关系匹配模型自由度,建立可用于联立计算的逐段降维GM模型。同时根据高纯度精馏塔吸收因子沿塔分布的强非线性特征,提出分段线性拟合求解组分回收率的线性GM模型。以空分装置的粗氩塔为例进行高纯度精馏塔的严格模型、降维GM模型和线性GM模型的对比计算。结果表明,降维GM模型的计算变量由逐板模型的2377个减少到34个,同样平台下收敛时间由6136 s缩短至1 s左右,而关键组分纯度模拟与严格机理模型一致。

关键词: 空分, 高纯度精馏塔, 降维模型, 分段模型