What are the main methods of drying rice?

At present, there are three main methods for rice drying, namely, conventional drying, mechanical ventilation drying and mechanical drying. Sunlight drying is a widely used method in rural areas and grass-roots grain depots, which uses sunlight heat and natural wind to reduce rice moisture. However, the sun-dried rice is easy to be mixed with impurities such as ash and sand, and it is easy to "crack the waist" (crack the rice), which affects the rice quality. Mechanical ventilation is a drying technology to convey normal temperature air or heated air to grain piles. Dry rice is of good quality. Mechanical ventilation equipment is simple. Simple operation and low investment, but the rice layer should not be too high, the drying time is long, and the drying ability is limited due to climatic conditions. Mechanical drying is to treat high-moisture rice with a dryer, and send hot air at 40~ 150℃ to the dryer to heat wet rice. It has the characteristics of fast dehydration, large precipitation range and large treatment capacity, but it has large investment, high energy consumption, high drying cost and complicated operation.