@@ 引言rn干燥是流程工业中重要的单元操作,是众多产品生产的关键步骤,在医药化工、食品、矿产加工、农产品加工等领域都有涉及[1-4].干燥效果的好坏不仅决定了生产单元的能耗,还会对产品的性能、形态、质量等产生影响.研究干燥过程的目的在于控制过程参数(包括干燥时间、进出口温度、风速等),对物料进行适度干燥,以使产品的湿度、质量等指标达到要求.在过程参数的设定过程中,干燥时间的控制(或称为干燥终点的确定)是影响产品质量最为关键的环节之一.%Real-time, on-line measurement of moisture content of particles has become one of the most important issues in drying process controlling. In this work, acoustic emission (AE) technique was applied to determine the moisture content. A characteristic frequency band of AE signals, which represents the moisture content, was obtained by using wavelet transform and spectral analysis. The analysis results showed that, with the decrease of moisture content, the 1st and 3rd energy fractions decreased and increased respectively, and the characteristic peak moved to lower frequency. Furthermore, a moisture prediction model based on the characteristic frequency analysis was constructed, which could quantitatively establish the relationship between the energy features and moisture. The root mean square error (RMSE) of the prediction model was 0. 0422, indicating that the model predicted the moisture with high precision. The AE method is a non-intrusive and rapid technique that makes online measurement possible,which has a positive impact on process optimization and product upgrading.
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