乙烯生产流程中联塔模拟与优化

在建立精馏塔单塔严格机理形式的开放式模型方程, 并对单塔进行模拟与优化的基础上, 对大规模乙烯生产过程中脱丙烷塔和脱丁烷塔组成的联塔系统进行模拟与操作优化研究.在对整个系统分析和处理后, 成功对其进行了模拟与优化, 结果对脱丙烷和脱丁烷塔精馏过程和操作优化具有指导意义.在优化过程中, 改进过的简约空间序列二次规划(reduced-space sequential quadratic programming, RSQP)算法具有比SNOPT和FMINCON更高的求解效率也得到验证.本文对联塔系统的研究和在模拟与优化过程中的处理、优化方法为将来整个乙烯生产流程系统的模拟与优化奠定了良好的基础.

Simulation and optimization of distillation column sequence in large-scale ethylene production

Based on authors’ previous work on single column simulation and optimization, this paper focuses on simulation and optimization of a distillation column system composed of a depropanizer and a debutanizer in ethylene production.The distillation column sequence was modeled with open-form equations.It had 4293 variables and 4188 equality equations characterized by its block triangular and highly sparse structure.The operation optimization problem was properly defined for profit improvement.It had relatively small degree of freedom, which could be effectively utilized in RSQP (reduced-space sequential quadratic programming) algorithm.The gradient information was obtained with hybrid automatic differentiation method.Variant implementation of SQP solvers including RSQP(from authors), SNOPT(from TOMLAB) and FMINCON(from Matlab Optimization Toolbox) were used to solve this problem.The results and efficiency value were compared.It was illustrated in numerical experiments that RSQP outperformed other solvers with the same initial values and convergence tolerance.This work can be useful in the simulation and optimization of the whole process of ethylene production.