Abstract

The demand for energy has been increasing all over the world, necessitating the introduction of novel devices to work with lower energy consumption. Modern technologies used for paddy drying are one of such processes which consumes a substantial amount of energy. The present work introduces a device (passive spiral) to be incorporated in fluidized bed dryers which could considerably reduce energy consumption and enhance drying characteristics while providing better nutritional values and quality end product in terms of paddy drying. Two conical fluidized bed with various cone angles (5° and 10°) and a columnar fluidized bed (0° cone angle) are used for the study to investigate the performance of dryers with and without spiral which shows that energy consumptions could be considerably reduced with the incorporation of a spiral inside the conical fluidized dryer and least with 10° cone angle. The pressure drop across the dryers, drying characteristics, the total energy consumptions such as blower and thermal energy consumption, nutritional values and milling quality of drying products are investigated for these three dryers with and without spiral and results are compared. The experiments are performed with two different inlet air velocities (1.1 and 1.6 m/s), and three different inlet air temperatures (55, 60, and 65 °C) with 1–3 kg batch size of paddy as a bed inventory. It is observed that the time taken to reduce the moisture content in conical bubbling fluidized dryer having cone angle 10° is lesser than the other two dryers. The drying rate is also found to be faster with the use of a spiral inside the three dryers than without the spiral. Incorporation of spiral exhibits better drying characteristics in terms of milling quality. Conical fluidized bed dryer having larger cone angle (10°) consumes less energy than the conical fluidized bed dryer having smaller cone angle (5°) and conventional fluidized bed dryer (0°). A total of around 40% less energy of blower and heater was consumed when spiral was used.

摘要

全世界对能源的需求一直在增加，因此需要引入新型设备以降低能耗。用于稻谷干燥的现代技术是消耗大量能源的此类过程之一。目前的工作介绍了一种设备（被动螺旋），该设备将被整合到流化床干燥机中，该设备可以显着降低能源消耗并增强干燥特性，同时在稻谷干燥方面提供更好的营养价值和优质的最终产品。两个具有不同锥角（5° 和 10°）的锥形流化床和一个柱状流化床（0° 锥角）用于研究带和不带螺旋的干燥器的性能，这表明可以显着降低能耗在锥形流化干燥器内部加入一个螺旋，至少有 10° 的锥角。对这三种有螺旋和无螺旋干燥器的干燥器压降、干燥特性、鼓风机和热能消耗等总能耗、干燥产品的营养价值和研磨质量进行了研究，并比较了结果。实验是在两种不同的进气速度（1.1 和 1.6 m/s）和三种不同的进气温度（55、60 和 65 °C）下进行的，以 1-3 kg 批次大小的稻谷作为床位库存。观察到在锥角为10°的锥形鼓泡流化干燥器中降低水分含量所需的时间少于其他两个干燥器。还发现在三个干燥器中使用螺旋的干燥速度比没有螺旋的要快。螺旋的结合在研磨质量方面表现出更好的干燥特性。具有较大锥角（10°）的锥形流化床干燥器比具有较小锥角（5°）的锥形流化床干燥器和传统的流化床干燥器（0°）消耗更少的能量。使用螺旋式时，鼓风机和加热器的能耗总共减少了约 40%。还发现在三个干燥器中使用螺旋的干燥速度比没有螺旋的要快。螺旋的结合在研磨质量方面表现出更好的干燥特性。具有较大锥角（10°）的锥形流化床干燥器比具有较小锥角（5°）的锥形流化床干燥器和传统的流化床干燥器（0°）消耗更少的能量。使用螺旋式时，鼓风机和加热器的能耗总共减少了约 40%。还发现在三个干燥器中使用螺旋的干燥速度比没有螺旋的要快。螺旋的结合在研磨质量方面表现出更好的干燥特性。具有较大锥角（10°）的锥形流化床干燥器比具有较小锥角（5°）的锥形流化床干燥器和传统的流化床干燥器（0°）消耗更少的能量。使用螺旋式时，鼓风机和加热器的能耗总共减少了约 40%。