| The separation of azeotropes has always been a hot issue in chemical production.With the increasing demand for clean production in China,the high energy consumption and pollution of traditional separation methods have become increasingly prominent.Exploring new separation processes that are more energy-efficient and environmentally friendly has become a key direction in recent years.Based on previous work,this paper establishes a set of solution strategies for distillation-membrane separation integrated process based on an improved membrane segmentation and recombination model,which can efficiently and quickly find the optimal distillation-membrane separation integrated process and obtain the optimal equipment and operating parameters of the process.Based on the solution and optimization of the integrated process using this strategy,we can further explore the impact of changes in factors such as pervaporation membrane operation temperature and membrane separation performance on the system,economy,and environmental performance of the integrated process.This paper proposes an improved membrane segmentation and recombination model,which improves and optimizes membrane separation processes by combining multiple small membrane modules into intermediate membrane modules and finally combining them into a large membrane.The model replaces the intermediate membrane module with a more reasonable and precise membrane separation model,dividing the membrane into countless small elements,calculating the material balance for each element,and then integrating to obtain the overall flow situation of the whole membrane.Theoretically,this model eliminates the problem of oversized membrane area caused by the inability to infinitely divide small membrane modules in previous models.By studying the distillation-membrane separation integrated process of n-heptanethiophene system separation,the reliability and rationality of the improved membrane segmentation and recombination model were verified.Using this solution strategy,the distillation-membrane separation integrated process was optimized for the hot issue of dimethyl carbonate(DMC)methanol removal in industrial production.Compared with conventional organic solvent extraction distillation processes and ionic liquid extraction + distillation processes under different feed concentrations and flow rates,the annual total cost and environmental impact indicators of the distillation-membrane separation integrated process were better.To further explore the impact of membrane performance changes on the characteristics of the integrated process,membrane types with different permeability to different components of the system were selected to explore the performance differences between the distillation-mixed membrane integrated process and the distillation-single membrane integrated process.The results showed that the integrated process constructed with a mixed membrane has unique advantages in terms of cost and environmental impact.Since the solution strategy proposed in this paper can quickly find the optimal distillation-membrane separation integrated process,in order to further promote its application in industrial production,the distillation-membrane separation integrated process was optimized for key parts of two typical industrial production processes,and compared with various parameters of the original process to explore the industrial application potential of the distillation-membrane separation integrated process.Methyl methacrylate(MMA)refining process and downstream separation process of renewable biomass resources acetone-butanol-ethanol(ABE)fermentation process were selected for study.For the integrated process design of MMA separation,the characteristics of the integrated process using different types of membranes permeable to different substances and membrane combinations after parameter modification were analyzed.For the integrated process design of butanol separation,the impact of different membrane operating temperatures,different types of membranes,and changes in membrane support on the characteristics of the integrated process were analyzed,and the characteristics of the integrated process using different types of membrane combinations were also analyzed.The results showed that flexible use of different types of mixed membranes and changes in membrane operating parameters,membrane operating temperature,and membrane support can make the distillation-membrane separation integrated process more economically and environmentally advantageous.The above conclusions not only provide guidance for the future industrialization of various types of membranes,but also provide a reliable basis for the widespread industrialization of the distillation-membrane separation integrated process. |
