Rice Points-process Drying Techniques And Technology Research

China is a rice-producing prower. Whether post-harvest rice drying is finished timely is directly related to the rice storage and subsequent processing. There are as many as5million tons of grain are lost because of not dryed in time.The ownership of China’s rice dryer are not enough, the drying capacity of the dryer is limited, but the rice harvest period is so short. Using existing dryer to complete a lot of rice drying work is a problem to be solved.Based on the theory of the ricepoints-processand, the points-process drying model is raised, points-process drying model is that the rice drying should be divided into three stages, its main technical points is that in the rice harvest season, the harvest of high moisture paddy by the beginning of cereal cleaning,drying,tempering, and then drying, and then tempering until its moisture content reduced to18.5%～18%, then transport the rice into the rice temporary positions with slow cooling, ventilation temporary; over the rice harvest season, take out the rice then drying, tempering,drying,tempering,until the moisture content dropped to14.5percent, or to achieve the requirements of a company, finally, take the rice into the stock.Through the field experiment,do the research of constant temperature drying, variable temperature drying and points-drying technology, also the contrast test of these drying technology. The results showed that points-drying technology is obviously superior to constant temperature drying, variable temperature drying technology whether from drying rice yield, equipment efficiency, or energy conservation. The rice points-process drying on the basis of ensuring the quality of paddy drying, can effectively relieve the holdings of existing equipment is too small during the harvest season of rice processing partial big contradiction, greatly improving the utilization rate of the rice drying equipment, increase the enthusiasm of people to purchase paddy dryer.Combined with characteristics of points-drying process, this paper puts forward PLC control scheme to the points-drying technology. In the field of control, through the program control, PLC will moderate the dryer grain rice moisture content control in users set range, and to the dryer can be the hot air temperature within and the corresponding hot air flow in closed loop control.The man-machine interface can show rice moisture content, drying in the warehouse temperature, many sets of dry food inside machine temperature can concentrate shows that in, also it can set new goals temperature parameters according to work need.In the points on the basis of process-drying model the dry process parameters are optimized. In the six tons/group of partial type rice dryer the orthogonal test showed that, in the high moisture section, we can take higher blast temperature (70～80℃), the tempering drying ratio we take1to3and we can take smaller values air volume(≤3400m3/h). in the low moisture section, it is better to take the lower temperature (40～45℃), a larger air volume quartile (3800m3/h)and a larger tempering drying ratio(3～5).