Study Of Refining Camellia Oil Experiment By Wiped Film Molecular Distillation And Simulation Of Liquid Film Flow And Heat Transfer

Camellia oil which is a natural product with high added values has important edible value.But now the technology of deeply processing camellia oil is imperfect,so the applications of it are limited in many high-end fields,such as,medicine,cosmetics and so on.Wiped film molecular distillation technology has absolute advantages in fine chemical separation and purification,because of its unique dynamic membrane evaporation process.It is of great theoretical significance and economic value to study the process of refining camellia oil which gained through the wiped film molecular distillation.Firstly,based on the VKL70-5FDRR wiped film molecular distillation apparatus,the experimental schemes and methods were formulated and the control parameters and its range of temperature,pressure,scraping speed and input quantity were determined.The orthogonal test method was used to select the test points,and experiment was carried out to refine camellia oil on VKL70-5FDRR device aiming at those test points.The acid value and peroxide value of camellia oil which was refined under different control parameters were tested according to the method in GB/T5530-2005 and GB 5009.227-2016.The results show that compared with the acid value and peroxide value of first grade camellia oil prescribed by GB/T 5530-2005,the camellia oil which was refined in this experiment has reached the first grade standard.Through the analysis of experimental data and product quality requirements,the comprehensive index of the system is the best when the temperature is 190 ?,system pressure is 1 Pa,scraping speed is 300 r/min,and the input quantity is 900 g/h.Secondly,according to the structure of the test equipment,the fluid mathematical model of camellia oil in evaporator was established.The flow characteristics of camellia oil on the evaporator surface were studied by computational fluid dynamics.The distribution of liquid film was analyzed especially in axial and circumferential directions,under different rotate speeds.According to the simulation results,with the increase of scraping speed,the distribution of liquid film tends to be uniform,which isconducive to refining,but the high rotating speed will lead to fluid splashing,which is not conducive to refining.Similarly,increasing input quantity properly is beneficial to the uniformity of film distribution and will increase the treatment capacity as well,however,the excessive input quantity will cause the thickening of liquid film,and on the contrary,the treatment capacity does not increase.The simulation results show that each process parameter has an optimal working point based on the structure of the test equipment,which is consistent with the experimental results.Thirdly,the heat transfer process of liquid film was simulated under different operating conditions including temperature,scraping speed and input quantity.The temperature distribution and heat transfer coefficient of liquid film in axial and circumferential directions were studied.The results show that the temperature of liquid film gradually rose from top to bottom,and the temperature changes fastest at the inlet,and became slower and slower along the downward direction,and then reached the set value.On the same circumference,the liquid film temperature rose rapidly from the front of the rotor to the back of the rotor,then dropped slowly until the next head wave decreases rapidly.For the heat transfer coefficient,Increasing temperature,rotate speed and input quantity properly can enhance the heat transfer,improve separation quality and distillation efficiency.Finally,the simulation results were analyzed,these results have a good reference value for the process optimization and parameter control of camellia oil refined by wiped film molecular distillation.