Study On Separation Of Methanol-acetone-butanone-water Quaternary Mixed Solvent

With the rapid development of chemical,electronics,medicine,photovoltaic and other industrial fields,the use of organic solvent quantity is becoming more and more frequent.As common organic solvent,Methanol,Acetone,and Butanone make up of the most use which inevitably produce a large number of methanol-acetone-butanone-water mixed solvent waste.It is necessary to search an effective way to recycle methanol,acetone,butanone from the waste solvent to achieve the maximize use of resources.There exists a group of azeotropic phenomenon in the mixed solvents,so it is difficult to separate the components completely in the raw materials only using the traditional distillation method.The existing relevant separation process was summarized and analyzed in this paper,on the basis of consideration of product purity,yield,energy consumption and other conditions,the technological route which combined liquid-liquid extraction and extractive distillation was determined as the method to separate the mixed solvents.Through the theoretical analysis,the glycerin was determined as the extraction agent in the liquid-liquid extraction process.The mixing time,string time and other factors were talked about on the efficiency in the extraction process through the single factor experiment.On the basis of comprehensive consideration of the efficiency,the mixing time of 30 min,the static time of 30 min,the solvent ratio of 1:1,extraction stages of two were determined.Under such circumstances,the water in raffinate decreased to below 1%by cross flow liquid-liquid extraction.The methanol-acetone azeotropic mixture in raffinate phase was separated by extractive distillation method.Through the determination of methanol-acetone binary system VLE data,water was determined as solvent in extractive distillation.Furthermore,the separation effects of theoretical plate number,raw material feed stage,extraction agent feed stage,reflux ratio and other parameters on the extractive distillation column and the solvent recovery column were investigated by the method of single factor experiment and orthogonal experiment.On the basis of simulation calculation,the extractive distillation unit was designed and verified.The experimental results showed that under the optimized conditions,the purity of recovered acetone reached 98.8%,methanol reached 99.5%,and the purity of recovered product reached the standard of recycling.The extraction solution was further treated by continuous distillation.The results showed that the water from the top of the column reached the standard of enterprise takeover and the glycerol from the bottom of the column was used as the liquid solvent extraction reagent.Through the process of liquid-liquid extraction and extractive distillation,the final purity of methanol reached 99.5%,acetone reached 98.8%,butanone reached 99.6%which reached the recycling standards of enterprise and the purity of the water reached the takeover standard.The work in this paper provided the technical reference for the recycling treatment of the organic waste solvents.