基于能量目标的芳烃萃取精馏溶剂评价模型

Solvent evaluation model base on energy consumption objective for aromatic extraction distillation units

以NRTL活度系数模型为基础,利用Aspen Plus对不同单组分萃取剂回收芳烃的萃取精馏装置进行了全流程模拟和工艺操作参数优化。综合考虑各操作变量及其关联,提出了基于局部耦合参数迭代优化的整体协同优化策略,在保证分离要求的条件下,以能耗为目标,对萃取精馏塔(EDC)、溶剂回收塔(ERC)的进料位置、ERC回流比等关键操作参数进行优化,建立过程能耗的物性关联模型。通过分析不同溶剂对芳烃萃取精馏过程能耗和分离效果的影响,提出了基于能耗目标的芳烃萃取精馏溶剂评价模型,结果表明影响芳烃萃取精馏过程能耗的关键物性为溶剂的分子量及常压沸点,所建立的过程能耗关联模型具有较高的关联性,其R2均大于0.9,可有效指导萃取精馏溶剂选择,为计算机辅助分子设计提供简化的目标函数。

Based on the NRTL activity coefficient model, the whole process simulation and process parameters were optimized by using Aspen Plus for extractive distillation equipment for aromatics recovery from different single component extractants. With consideration of multiple variables and their interactions, a coordinative optimization strategy was further proposed from iterative optimization of local coupling parameters. At given separation specifications, energy consumption was optimized through adjusting critical operating parameters, such as the feed stages of extractive distillation column(EDC), the feed stage of entrainer recovery column(ERC) and the reflux ratio of ERC. An energy consumption model correlated with physical properties was presented based on the energy transfer rules. A solvent evaluation model based on the energy consumption objective for aromatic extraction distillation processes was put forward through the analysis of energy consumption and separation efficiency with different solvents. The results show that the molecular weight and boiling point of solvent are the pivotal factors influencing the energy consumption of aromatics extraction distillation units. There is a high correlation of the energy consumption model with the R 2 value bigger than 0.9 which can guide the selection, evaluation and design of the extracting solvent for an aromatic ED process.