Experimental Study On Drying Process And Control Process Of Rice Temperature Change

The improvement of the national economy has made the people’s demand for high-quality ingredients increasingly increasing.Heilongjiang Province is China’s largest commodity grain base.The rice planting area is wide,the harvest time is relatively concentrated,and the water content is high.Because of the lack of drying,it causes a lot of losses,and the drying equipment can be used in a short time.Reduce the moisture content of rice to meet the requirements of safe storage.However,the drying process is a complex nonlinear system,and the influencing factors are changeable.There is a systematic time lag problem,which affects the further improvement of the automation level,causing problems such as bursting and scorching in the drying process,resulting in a decline in grain quality.By adopting the PLC control system of rice temperature-changing and quality-drying process combined with deep-bed drying and drying characteristics,the quality of dried rice can be improved to some extent.In this paper,aiming at the problem of quality degradation during rice drying,the rice temperature-changing quality control drying control system was taken as the research object,and the research on variable temperature and quality drying process,drying control model,variable temperature regulating device and the development of the whole machine system were carried out.The main research contents are as follows:（1）Based on the combination of drying process parameters of rice quality,design L₉（3⁴）orthogonal test,using Matlab to carry out cubic convolution interpolation of drying process temperature,wind speed and water content,forming the value of taste and roughness.The protein content,starch content,taste value and roughness rate are normalized and the comprehensive index affects the surface.By drying the surface,the highest comprehensive index is obtained,and the rice is set at a temperature of 45℃when the water value is greater than 16%.The wind speed is 0.16 m/s.When the water content is lower than 16%,a variable temperature drying process of 35℃and a wind speed of 0.64 m/s is used.（2）By simplifying the deep bed drying process into a thin layer drying model,the heat transfer and mass transfer process between grains and grains in different states is described parametrically,and the network diagram of coupling control relationship among various influencing factors is obtained,which is returned by L₈（2⁷）Experiment,establish a dry preheating time control model,and obtain a flow chart of the whole machine operation process based on the quality and drying temperature change process.（3）Using the principle of airflow mixing,a variable temperature regulating mixing device was designed,and L₉（3⁴）simulation analysis was performed using FLUENT.The device was used to adjust the temperature of the mixed hot and cold airflow.The difference between the control temperature and the target was 0.96℃,and the temperature parameters were qualified.The rate is 100%.（4）Based on the above research content,a PLC-based variable temperature and quality drying control system was developed.The target moisture value was set at 14.5%,and the experimental results showed that the average moisture value was 14.6%,the standard deviation was 0.035,and the control chart was not violated.phenomenon.Through the research,it is concluded that on the basis of simplifying the description of the drying process parameters,the variable temperature drying process combined with the deep bed drying theory to develop the control system of the dryer can improve the comprehensive score of the rice after drying.The variable temperature drying process,combined with the innovative design of the variable temperature regulating device,can change the temperature of the drying process.The PLC fuzzy control system was used to carry out the drying process.The dried rice taste value was 82,the roughness rate was 3.4%,and the whole machine was running reliably,realizing the temperature-changing and quality-drying operation of rice.