低温低湿条件下海鳗冷风干燥动力学特性

利用两级除湿热泵干燥装置模拟低温、低湿环境,研究海鳗干燥动力学特性。研究结果表明,海鳗低温、低湿冷风干燥时无恒速干燥阶段,而是一开始就进入降速干燥。在整个降速干燥过程中存在2个阶段,即第一降速干燥阶段和第二降速干燥阶段。分析了两阶段中水分扩散特性。采用非线性回归分析比较不同的干燥模型,在试验条件下Page模型拟合较优,并求得模型表达式。通过菲克第二扩散定律和Arrhenius方程求得实验条件下的有效水分扩散系数及扩散活化能分别为(2.6197～4.0224)×10-10m2/和15.23kJ/mol。

Cold-air Drying Kinetic Characteristic of Pike Eel at Low-temperature and Low-relative Humidity

Two-stage heat pump dryer was used to simulate low temperature and low relative humidity condition that drying kinetics of pike eel was studied.Results indicated that low temperature,low relative humidity drying of pike eel showed no constant rate period and was entering the falling rate period in the very beginning.The whole falling rate period could be divided into two parts named the first falling rate period and the second falling rate period,furthermore,their moisture diffusion characteristic was analyzed.Different drying models were compared by non-linear regression analysis,and concluded that under experiment conditions Page model fitting best,also figure out the model expression formula.Combining Fick’s second law for diffusion with Arrhenius-type relationship calculated that effective moisture diffusivity and diffusion activation energy were 2.6197～4.0224×10-10 m2/s & 15.23 kJ/mol,respectively.