包膜尿素控制释放过程传质模型

根据质量守衡定律和F ick扩散定律建立了包膜尿素控制释放过程的传质模型,并用3种新颖的石蜡-松香混合物包膜尿素在蒸馏水中的释放数据和扫描电镜照片对模型进行了验证。结果表明,该模型能有效地描述和预测由扩散机制控制的包膜尿素的养分释放行为,拟合的相关系数R2分别为0.997 6,0.997 3和0.998 4。模型显示,包膜尿素的养分释放速率与膜的有效扩散系数Deff成正比,与尿素粒径的平方及膜的厚度成反比。

Mass transfer model for coated urea in controlling-release process

According to mass conservation and Fick′s diffusion law,a mathematical model for describing the(nutrient) release from coated urea was proposed.The model was verified by the release data in distilled water of three sorts of novel paraffin wax-rosin coated urea and their scanning electron micrographs.The results indicate that the model is effective in describing and predicting the delivery behaviors for diffusion-controlled coated-urea and the regression correlation coefficient R~2 is 0.997 6,0.997 3 and 0.998 4 respectively.The model shows that the nutrient release rate of coated urea is direct proportion to effective diffusion coefficient D_(eff),and inverse proportion to the square of urea granule diameter,and inverse proportion to the coating thickness.