Abstract In the experiment of measuring drying characteristic curve, the drying curve (X-t) is drawn according to the change of moisture content (X) of material with time (t). The drying rate (U) is obtained by derivation, which is then plotted vs. X to get the drying rate curve (U-X). Because there are a great number of X-t data points, the U-X curve fluctuates wildly. It is important to select the appropriate processing method to get the accurate U-X curve for studying the drying process. In this paper, several kinds of processing methods of the drying curve are compared. Results show that when the interval is too narrow, the difference quotient method may bring great fluctuation. Although increasing the interval can reduce the fluctuation, some important details in the U-X curve maybelost when it is too wide. In contrast,derivation aftersmoothing the X-t curve can significantly reduce the fluctuation of the U-X curve and well keep its trend. Another better processing method is the piecewise fitting, by which the U-X curve can be clearly divided into different stages, and thereby more accurate key data can be acquired. In addition to linear fitting, hyperbolic model can also be used to fit the U-X curve in the deceleration stage, both of which have good fitting effect.
LI Zhong-Ze, LIU Wen-Fang, WANG Ye, ZHAO Zhi-Ping. Discussion on Processing Methods of Drying Curve in Drying Experiment[J]. Chinese Journal of Chemical Education, 2022, 43(20): 49-56.
