高水分玉米真空低温干燥工艺生产性试验研究

东北是我国玉米的主产区，产量占全国的30％～40％。受自然条件的影响，玉米收获水分常达22％～30％；成熟度及含水率都不均匀。根据玉米热敏性物料干燥的热特性及市场要求，考虑到它的热稳定性及破碎敏感性的特点，采用真空低温干燥技术进行了生产性试验，设计了300t／d高水分玉米真空低温连续干燥工业自动化生产线，对生产性试验关键技术进行了分析和研究。依据试验结果，分析玉米含水率、干燥介质温度、真空度、玉米温度、干燥时间、汽化蒸发温度等参数之间的联系与相互作用。生产试验表明：玉米含水率在24％时，维持干燥塔内真空度，采用高温水加热，汽化蒸发温度40～43℃，一次降水幅度达到10％～15％，保证了玉米品质的色、香、味、形及营养成分，具有干燥品质好、降水速度快、产量高、能耗低、操作方便、经济性价比高等优点。

Industrial Experiments on Low-temperature and Vacuum Drying Technology of Corn with High Moisture Content

Northeast of china is corn major production region, in which, corn capacity is 30 to 40 percent of total yield in china. Limited by natural factors, water content of harvest corn is 22 to 30 percent; the maturity and moisture content are all non-uniform. According to market requirement and heat character of drying heat-sensitive material, and heat stability and fragile character, by production test method of low-temperature vacuum drying technology, we analyze and research drying technology and drying mode, design auto production line of low-temperature vacuum continuous drying of high-moisture corn with the capacity of 300tons per day, analyze and research key technology of production test. Based on the test result, we analyze interrelation and interaction between parameters, such as moisture content of corn, media temperature for drying, vacuum degree, corn temperature, drying time, evaporating temperature, etc. The operation test shows, when moisture content of corn is 24 percent, the vacuum degree in the drying tower is minus 0.096MPa, corn is heated with 95 to 100 Celsius degree water, evaporating temperature is 40 to 43 Celsius degree, range of corn moisture removed for once is 10 to 15 percent. By this technology, we retain its color, favor, taste, shape and nutrient composition of corn, this technology has characters of good drying quality, moisture removed rapidly, large capacity, energy saving, easy operation, high ratio of price to performance.