The Study On The Method Of Optical Real-time Detection For The Process Of Vacuum Distillation

Distillation is a common physical and chemical process,widely used in biological,chemical,pharmaceutical,petroleum and other fields.Among them,vacuum distillation has important application value because it can boil at low temperature and will not decompose the material at high temperature.In recent years,with the development of seawater desalination and alcohol fractionation,real-time monitoring of the process of vacuum distillation has become very significant.In this paper,based on the spatial refractive index resolution of liquid cylindrical lens,a new method for real-time measurement of evaporation and concentration changes in the process of vacuum distillation is proposed.By using these methods,the physical parameters of evaporation and concentration changes in vacuum evaporation of seawater and fractional distillation of alcohol solution are measured.the specific work content is as follows:1.Based on the study of the process of vacuum distillation,a method of optical detection is proposed to study the process of vacuum distillation using liquid cylindrical lens as the core optical element.The characteristics of this method are that evaporation and concentration change can be measured simultaneously through a group of experimental images,which has the advantages of simple operation and visualization of the process of vacuum distillation.2.Based on the related theories of the process of vacuum distillation,the laws of evaporation and concentration of residual solution with pressure and temperature are deduced,and the experimental results are consistent with the theoretical expectations.According to the formula and the setup of optical detection system,the simulation program is written and the simulation results are in good agreement with the experimental results.3.An optical experiment system is built based on liquid cylindrical lens as the core optical element,the vacuum device is built based on the vacuum pump as the main pressure-relief device structures,this paper has completed two experiments of the decompression evaporation of seawater and the fractionation of alcohol aqueous solution,physical parameters such as evaporation,residual amount and concentration changes are calculated,and corresponding experimental conclusions are obtained by fitting curves with experimental data.4.The results of vacuum distillation under different conditions are obtained by changing temperature,pressure and volume of solution.The results of the two groups of experiments show that the vacuum distillation factor β has no significant change at the temperature of 20℃～40℃ and can be regarded as a constant.