Drying Technology ( IF 3.3 ) Pub Date : 2021-03-22 , DOI: 10.1080/07373937.2021.1898418 Mojtaba Nosrati 1 , Dariush Zare 1 , Seyed Mehdi Nassiri 1 , Guangnan Chen 2 , Abdolabbas Jafari 1
Abstract
Moisture variation and fissure formation of rice kernels during multi-stage intermittent drying (MSID) were simulated and analyzed based on the experimental data obtained in a laboratory-scale infrared-assisted vibratory bed dryer. The variations of drying parameters included far-infrared radiation (FIR) intensity (0, 1000 and 2000 W m−2), inlet drying air temperature (30, 40 and 50 °C), drying duration (15, 30 and 40 min), and tempering ratio (0, 2, 4 and 6). Two-dimensional moisture distribution within individual kernel was predicted. Drying rate, percentage of the cracked kernel (PCK), and specific energy consumption (SEC) were also determined, experimentally. By assessing PCK and SEC and simulation results, it was found that the magnitude of 10% d.b. mm−1 was considered as an index for the critical value for moisture content gradient (MCG) to achieve the suitable drying and tempering duration. It was further recommended that the intermittent drying duration at each stage should be selected in such a way that the MCG value does not exceed the critical level and the shortest possible tempering duration should be chosen in a manner that at least 40% of critical level of MCG be eliminated. The suitable treatment for intermittent drying was selected at FIR intensity of 1000 W m−2, inlet air temperature in 40 °C, drying duration in 30 min, and tempering ratio in 4.
中文翻译:
FIR-组合式干燥机间歇式干燥糙米的试验与数值研究
摘要
基于实验室红外辅助振动床干燥机的实验数据,模拟分析了多级间歇干燥(MSID)过程中米粒的水分变化和裂隙形成。干燥参数的变化包括远红外辐射(FIR)强度(0、1000和2000 W m -2)、入口干燥空气温度(30、40和50°C)、干燥时间(15、30和40分钟) , 和回火比 (0, 2, 4 和 6)。预测了单个籽粒内的二维水分分布。还通过实验确定了干燥速率、碎仁百分比 (PCK) 和比能量消耗 (SEC)。通过评估 PCK 和 SEC 以及模拟结果,发现 10% db mm -1的量级被认为是水分含量梯度(MCG)的临界值的指标,以实现合适的干燥和回火持续时间。进一步建议,每个阶段的间歇干燥时间应选择为使 MCG 值不超过临界水平,并且应选择尽可能短的回火持续时间,以使至少 40% 的临界水平MCG被淘汰。间歇干燥的适宜处理选择为远红外强度为 1000 W m -2,进风温度为 40 ℃,干燥时间为 30 min,回火比为 4。