Montero Irene, Miranda Teresa, Arranz Jose Ignacio, Rojas Carmen Victoria
Department of Mechanical, Energetic, and Materials Engineering, Industrial Engineering School, University of Extremadura, Avenue Elvas s/n, 06006, Badajoz, Spain; E-Mails:
Int J Mol Sci. 2011;12(11):7885-97. doi: 10.3390/ijms12117885. Epub 2011 Nov 15.
The thin-layer behavior of by-products from olive oil production was determined in a solar dryer in passive and active operation modes for a temperature range of 20-50 °C. The increase in the air temperature reduced the drying time of olive pomace, sludge and olive mill wastewater. Moisture ratio was analyzed to obtain effective diffusivity values, varying in the oil mill by-products from 9.136 × 10(-11) to 1.406 × 10(-9) m(2)/s in forced convection (m(a) = 0.22 kg/s), and from 9.296 × 10(-11) to 6.277 × 10(-10) m(2)/s in natural convection (m(a) = 0.042 kg/s). Diffusivity values at each temperature were obtained using the Fick's diffusion model and, regardless of the convection, they increased with the air temperature. The temperature dependence on the effective diffusivity was determined by an Arrhenius type relationship. The activation energies were found to be 38.64 kJ/mol, 30.44 kJ/mol and 47.64 kJ/mol for the olive pomace, the sludge and the olive mill wastewater in active mode, respectively, and 91.35 kJ/mol, 14.04 kJ/mol and 77.15 kJ/mol in natural mode, in that order.
在太阳能干燥器中，于20 - 50°C的温度范围内，对橄榄油生产副产物的薄层干燥行为在被动和主动运行模式下进行了测定。空气温度的升高缩短了橄榄果渣、污泥和橄榄油厂废水的干燥时间。通过分析含水率来获取有效扩散率值，在强制对流（空气流量(m_a = 0.22) kg/s）条件下，橄榄油厂副产物的有效扩散率值在(9.136×10^{-11})至(1.406×10^{-9}) (m^2)/s之间变化；在自然对流（空气流量(m_a = 0.042) kg/s）条件下，有效扩散率值在(9.296×10^{-11})至(6.277×10^{-10}) (m^2)/s之间变化。利用菲克扩散模型获得了每个温度下的扩散率值，且无论对流方式如何，扩散率值均随空气温度升高而增大。有效扩散率与温度的关系由阿累尼乌斯型关系式确定。在主动模式下，橄榄果渣、污泥和橄榄油厂废水的活化能分别为38.64 kJ/mol、30.44 kJ/mol和47.64 kJ/mol；在自然模式下，活化能依次为91.35 kJ/mol、14.04 kJ/mol和77.15 kJ/mol。
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