Research On Optimization Of High-efficiency And Energy-saving Drying Process For Camellia Seeds

Camellia oil is one of the edible vegetable oils in my country.Unsaturated fatty acids account for more than 90%of the whole tea oil.It also contains a variety of healthy ingredients.It is known as "Oriental Olive Oil".In recent years,with the continuous improvement of people’s living standards in our country,the relationship between supply and demand in the edible oil market has become increasingly tense.The industry related to camellia oil has been vigorously supported by government departments at all levels.Many farmers and enterprises have rapidly expanded the scale of camellia oleifera planting,and the output of camellia oleifera fruit has been increasing year by year.Therefore,the processing of camellia seeds has also received more and more attention.In this paper,the hot air drying research was carried out on the fresh camellia seed part,and the drying effect of hot air drying under different conditions(temperature,wind speed and stacking thickness)was studied,and the degree of influence on the drying time and drying energy consumption of the system under different conditions was also analyzed,compared and analyzed the drying effect of camellia seeds per unit mass by hot air drying and heat pump drying,aiming to provide an efficient and energy-saving drying process for the multi-factor hot air drying of camellia seeds and provide a theoretical reference for the development of hot air drying equipment.The main findings of this paper are as follows:(1)By studying the hot air drying characteristics of Camellia oleifera seeds,under the conditions of different temperatures,wind speeds and stacking thicknesses,record the drying characteristics of each parameter,as well as the drying time and drying energy consumption during the drying process,and draw the drying characteristic curve by drawing the drying characteristic curve.and data analysis methods to derive the reference process.The research on the drying characteristics of camellia seeds by hot air shows that the drying rate is high first and then low.The main factors affecting the drying rate are the influence of the physical properties of the camellia seeds and the influence of the external drying environment(drying temperature,drying wind speed and drying stack thickness).The higher the temperature,the lower the humidity of the camellia seeds at the same time,the faster the mass and heat transfer of the camellia seeds,thereby shortening the drying time of the camellia seeds.The optimization experiment of hot air drying of camellia seeds showed that the safe moisture(9.48%)was used as the drying end point,the multi-factor variance and multiple comparison test were used as the analysis methods,and the specific drying parameters selected during the experiment were used as independent variables to analyze.When the drying time is used as the evaluation index,the optimal process parameters are:drying temperature of 80℃,drying wind speed of 2m/s,and drying stack thickness of 2cm.When the drying energy consumption is used as the evaluation index,the optimal process parameters are:drying temperature of 80℃,The drying wind speed is 0.5m/s,and the drying stacking thickness is 2cm.(2)To study the hot air drying characteristics of Camellia oleifera seeds under different temperature,wind speed and thickness conditions.The relationship between water content and water ratio(MR)and time was recorded,and the relevant drying characteristic curve was drawn,so as to analyze the changing law of water content during hot air drying of camellia oleifera seeds and the use of hot air drying mathematical model and BP neural network.Data processing,fitting and verification of the rationality and accuracy of the model are carried out according to the changing law of water content.In this paper,the commonly used drying mathematical model and BP neural network model are used to fit the hot air drying process of Camellia oleifera.The results show that the commonly used Page mathematical model has a high degree of fitting to the drying process,and the fitting condition of each drying situation reaches 0.97.The above;and the BP neural network model in the process of training,verification,and testing,the model fitting degree is above 0.98,indicating that the parameters obtained by the BP neural network model training can more accurately predict the moisture content of camellia seeds in the process of hot air drying.changing laws.From the relationship between the moisture content and time of heat pump drying and hot air drying,it can be concluded that when the drying conditions remain unchanged,the hot air drying characteristics of the two are the same,and the same model can be used to fit and predict the moisture content characteristic curve.(3)Experiments on the wind speed and stacking thickness of the camellia seed material layer showed that after obtaining the porosity of the camellia seed material layer by the indirect method,the relationship between the pressure difference and the thickness and the wind speed of the camellia seeds was simulated and solved,and the relationship between the pressure difference and the dependent variable was calculated.The mathematical relationship is fitted and verified by a variety of mathematical equations,and the functional relationship that is most suitable for the actual situation is obtained.There was no significant difference in the pressure loss of camellia seeds under low wind speed and low material layer thickness,but the pressure difference of camellia seeds changed greatly under high wind speed and high material layer thickness.When the thickness of camellia seeds is constant,the relationship between wind speed and pressure difference conforms to a quadratic function,and the specific function expressions under the respective wind speeds are obtained,and the R2 values are all above 0.99.At the same time,the coefficients of the function expressions under different thicknesses are Differently,an expression between quadratic function coefficients and thickness can be derived.(4)After obtaining the mathematical model of heat pump drying energy consumption and the mathematical model of material pressure drop,the energy consumption of the heat pump unit can be obtained through the relationship between the wind speed and the fan power.When the safe moisture content(9.48%)is reached,the drying energy consumption is used as the evaluation index.The optimal process parameters are:the wind speed is 0.5m/s,the hot air temperature is 50℃,and the material layer thickness is 2cm.At the same time,it can be seen from the simulation of material layer drop that the thicker the camellia seed stacking thickness,the greater the pressure difference between the two sides of the material layer,resulting in a decrease in the overall pressure in the system,thereby increasing the fan power and energy consumption.By calculating the actual energy consumption of the heat pump and the energy consumption of the air supply fan,the drying energy consumption of camellia seeds per unit mass is obtained,and an efficient and energy-saving drying process is determined.The optimal operation strategy is:hot air temperature 80℃,The wind speed is 0.5m/s,and the stacking thickness is 10cm.