Experimental study of the effect of ambient air humidity on the efficiency of tribo-aero-electrostatic separation of mixed granular solids
Experimental study of the effect of ambient air humidity on the efficiency of tribo-aero-electrostatic separation of mixed granular solids
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DOI：
10.1109/ias.2011.6074274
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发表时间：
2011-11
期刊：
影响因子：
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通讯作者：
M. Miloudi;M. Remadnia;C. Dragan;K. Medles;A. Tilmatine;L. Dascalescu
中科院分区：
文献类型：
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作者：
M. Miloudi;M. Remadnia;C. Dragan;K. Medles;A. Tilmatine;L. Dascalescu
混合颗粒绝缘材料可以通过在与流态化空气方向垂直的电场作用下在流态化床中摩擦充电来实现静电分离。本文的目的是评估环境空气湿度对这种摩擦-空气-静电分离过程的结果的影响，即在产生电场的两个电极上收集的颗粒的质量。待分离混合物由丙烯腈、丁二烯、苯乙烯(ABS)和高抗冲聚苯乙烯(HIPS)组成，这些混合物来自废旧电子电气设备的回收。在两个环境相对湿度(RH=20%和RH=40%)下进行了两个持续时间(30 S和60 S)的实验，结果表明，当混合物的初始质量超过一定值时，分离变得有效。然后利用实验设计方法和商业软件Mode5.0研究了两个工艺变量的影响：用作高压电极的金属传送带的速度和环境空气的湿度。研究发现，分离的有效性在很大程度上取决于后一个因素。对两种粒子的电荷层进行的表面电位衰减测量有助于解释分离结果：在较高的相对湿度下，亲水性ABS粒子与接地板接触时释放电荷的速度更快。因此，它们的数量少于在摩擦-空气-静电分离室出口处收集的HIPS颗粒。
Mixed granular insulating materials can be electro-statically separated by tribocharging them in a fluidized bed affected by an electric field orthogonally oriented to the direction of the fluidization air. The aim of the present paper is to evaluate the effect of ambient air humidity on the outcome of this tribo-aero-electrostatic separation process, i.e. the mass of the granules collected at the two electrodes that generate the electric field. The mixture to be separated was composed of Acrylonitrile Butadiene Styrene (ABS) and High Impact Polystyrene (HIPS) originating from the recycling of waste electric and electronic equipment. A set of experiments carried out for two durations (30 s and 60 s), at two values of ambient relative humidity (RH = 20% and RH = 40%), pointed out that the separation becomes efficient beyond a certain value of the initial mass of the mixtures. The experimental design methodology and commercial software MODDE 5.0 were then employed for investigating the effects of two process variables: the speed of the metallic conveyors that serve as high-voltage electrodes, and the humidity of ambient air. The effectiveness of separation was found to depend significantly on the latter factor. Surface potential decay measurements performed on charged layers of the two sorts of particles facilitate the interpretation of separation results: at higher RH, the hydrophilic ABS granules loose faster their charge when in contact with a grounded plate. As a consequence, they are in less number than the HIPS granules to be collected at the exit of the tribo-aero-electrostatic separation chamber.