流化床中吸附干燥大豆特性研究

Study on Soybean Seeds Quality after Sorption Drying in Fluidized-Bed

在流化状态下种子(大豆)与硅胶能够很好的混合,通过湿含量梯度进行传质,干燥后种子质量显著提高;种子与硅胶粒径不同,便于分离。通过实验比较了在不同混合比和不同流化条件下种子的干燥特性。随着吸附剂的加入,干燥速率明显增大,并且随着风速的提高、硅胶与种子混合比的增大,干燥速率也随之提高。通过试验还表明,采取流化床与固定床动静结合的吸附干燥方式,在节能和产品质量方面有一定的优势。

Soybean seeds were contacted with silica gel in a fluidized bed, where mass transfer is driven by moisture concentration gradient. It has the advantage of well-mixing the solid adsorbent （silica gel） with the material being dried （soybean seeds） in fluidization state, and thus the dried seeds quality could be improved sincethey are in a uniform environment of low humidity. Separation of these two solids once desired moisture content is reached can be realized due to the size difference as well as the operation conditions of fluidization. The drying kinetics was compared under different mass ratios and fluidization conditions. The dispersion rate of soybean seeds was increased with addition of either silica gel particles, whereas the drying rate was improved with the gas velocity and mass ratio of silica gel. A scheme of sorption drying in a hybrid process of fluidized/fixed bed is proposed in the viewpoint of energy efficiency and product quality.