Due to the nonlinearity, strong coupling and hysteresis of the parameters used in measuring the grain drying process, it is always a challenge to perform accurate control of the drying system. The purpose of this paper is to describe the design of a suitable neural network model to control the grain dryer more effectively. First, the operating mechanism of a continuous grain dryer and the principle of the heat and mass transfer that can be used in the process of grain drying was analyzed before an intelligent control system was designed accordingly. Second, an intelligent control system based on the Back Propagation Neural Network (BPNN) was developed. The BPNN was the optimal model selected based on a series of comparative test results. According to the BPNN prediction of the moisture content of dried rice, the system could adjust the rate of grain discharge of the dryer, and then control the drying process accurately. Finally, the neural network control model was simulated using computer simulation technology, and was optimized by comparing analysis results with experimental results. The results showed that the optimized intelligent control system using BPNN has the advantage of strong stability and good noise handling, and could have great potential for future implementation studies.

In order to study the effect of corn kernel composition and physical structure on moisture distribution and transfer process and obtain the optimal tempering-drying parameters of corn kernel, a physical model was constructed with four different components as follows: seed coat, horny endosperm, farinaceous endosperm and embryo. The drying model was established based on the assumption of different diffusion coefficients and same thermal conductivity for the four components. The software of COMSOL Multiphysics was used to simulate the heat and mass transfer process inside the corn kernel during the thin-layer drying. The results showed that the least total drying time and the best drying quality were achieved under the multistage circulating drying of 10 min hot air drying and 60 min tempering, and the tempering degree was up to 0.9207.