Perez-Martinez Borja B, Lopez-Urionabarrenechea Alexander, Serras-Malillos Adriana, Acha Esther, Caballero Blanca Maria, Asueta Asier, Arnaiz Sixto
Chemical and Environmental Engineering Department, Faculty of Engineering of Bilbao, University of the Basque Country (UPV/EHU), Plaza Ingeniero Torres Quevedo 1, 48013 Bilbao, Spain.
Basque Research and Technology Alliance (BRTA), GAIKER Technology Centre, Parque Científico y Tecnológico de Bizkaia, Edificio 202, 48170 Zamudio, Spain.
ACS Omega. 2024 Jul 16;9(30):32593-32603. doi: 10.1021/acsomega.4c01415. eCollection 2024 Jul 30.
Rejected streams emerging from waste sorting and recycling plants are still capable of being valorized by unconventional recycling routes. This is the case of the plastic-rich fraction generated after the treatment of waste electrical and electronic equipment (WEEE). However, the material complexity of this stream supposes a handicap when it comes to obtaining repetitive results in laboratory-scale recycling processes. This work aims to highlight the influence that the pretreatment (mainly particle size reduction) of a real WEEE plastic-rich stream has on the variability of the concentration of halogens (representative pollutants) in the oils obtained from its recycling via pyrolysis. The pretreatment steps were based on the standards of the European Committee for Standardization (ECN) for the analysis of waste samples. Four samples were studied: the WEEE plastics as received; two milled samples (2 and 1 mm particle size) derived from the original one; and a simulated sample composed of virgin polymers. All the samples were treated under the same conditions: 500 °C reaction temperature, 15 °C min heating rate, 30 min dwell time, and a 1 L min nitrogen purge flow. The oils obtained in, at least, two pyrolysis tests performed on the same sample were deeply characterized, and the results were compared. The oils derived from the "as-received" sample showed an unacceptable relative standard deviation (RSD, ∼42%) in the chlorine concentration. The sample milled to 2 mm reduced the RSD on the concentration of chlorine in the oils down to 8%, while no enhancement in the results was observed for the further milled sample. The other two major pyrolysis fractions were also characterized, showing an overall enhancement in the RSD of the analysis of the main components of the gases, while no improvement in the solids pollutants' characterization was achieved.
从垃圾分类和回收工厂排出的废弃物流仍可通过非常规回收途径实现价值利用。废弃电子电气设备（WEEE）处理后产生的富含塑料的部分便是如此。然而，在实验室规模的回收过程中，该物流的材料复杂性使得难以获得重复性结果。这项工作旨在突出真实的富含WEEE塑料的物流的预处理（主要是粒度减小）对通过热解回收得到的油中卤素（代表性污染物）浓度变异性的影响。预处理步骤基于欧洲标准化委员会（ECN）分析废物样品的标准。研究了四个样品：原样的WEEE塑料；由原样衍生的两个研磨样品（粒度分别为2毫米和1毫米）；以及一个由原始聚合物组成的模拟样品。所有样品均在相同条件下处理：反应温度500°C，加热速率15°C/分钟，停留时间30分钟，氮气吹扫流量1L/分钟。对至少在同一样品上进行的两次热解试验中获得的油进行了深入表征，并对结果进行了比较。从“原样”样品得到的油中氯浓度的相对标准偏差（RSD，约42%）不可接受。研磨至2毫米的样品将油中氯浓度的RSD降低至8%，而进一步研磨的样品未观察到结果有改善。还对其他两个主要热解馏分进行了表征，结果表明气体主要成分分析的RSD总体有所增加，而固体污染物表征方面没有改善。
