Control of steam input to the pyrolysis-gasification of waste plastics for improved production of hydrogen or carbon nanotubes
Control of steam input to the pyrolysis-gasification of waste plastics for improved production of hydrogen or carbon nanotubes
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DOI：
10.1016/j.apcatb.2013.09.018
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发表时间：
2014-04-05
影响因子：
22.1
通讯作者：
Williams, Paul T.
中科院分区：
文献类型：
--
作者：
Acomb, Jonathan C.;Wu, Chunfei;Williams, Paul T.
碳纳米管（CNTs）已被证明可以作为废塑料气化制氢的高价值副产品。在这项工作中，研究了气化过程中的蒸汽含量，以提高碳纳米管的纯度。对低密度聚乙烯（LDPE）、聚丙烯（PP）和聚苯乙烯（PS）三种不同的塑料进行了两段热解气化反应研究。塑料样品在600摄氏度的氮气中进行热解，然后释放出的气体进入第二阶段，在第二阶段注入蒸汽，气体在800摄氏度的温度下在镍-氧化铝催化剂的存在下进行重整。为了研究蒸汽对碳纳米管产量的影响，采用了0、0.25、1.90和4.74 g h（-1）的注蒸汽速率。由这三种塑料制成的碳纳米管都是多壁碳纳米管，直径在10到20纳米之间，长度在几微米之间。对于所有的塑料样品，随着蒸汽重整和沉积碳气化的增加，蒸汽注入速度的提高导致氢气产量的增加。通过TEM、TPO和拉曼光谱可以观察到，通过控制注汽速率可以得到高质量的CNTs。LOPE的产率在0 gh（-1）时达到最大，而PP和PS的产率在0.25 gh（-1）时达到最大。总的来说，PS在0.25 g h（-1）时获得了最大的碳纳米管收率，塑料到碳纳米管的转化率为32 wt%。(C) 2013 Elsevier B.V.版权所有
Carbon nanotubes (CNTs) have been proven to be possible as high-value by-products of hydrogen production from gasification of waste plastics. In this work, steam content in the gasification process was investigated to increase the quality of CNTs in terms of purity. Three different plastics low density polyethylene (LDPE), polypropylene (PP) and polystyrene (PS) were studied in a two stage pyrolysisgasification reactor. Plastics samples were pyrolysed in nitrogen at 600 degrees C, before the evolved gases were passed to a second stage where steam was injected and the gases were reformed at 800 degrees C in the presence of a nickel-alumina catalyst. To investigate the effect that steam plays on CNT production, steam injection rates of 0, 0.25, 1.90 and 4.74 g h(-1) were employed. The CNTs produced from all three plastics were multiwalled CNTs with diameters between 10 and 20 nm and several microns in length. For all the plastic samples, raising the steam injection rate led to increased hydrogen production as steam reforming and gasification of deposited carbon increased. High quality CNTs, as observed from TEM, TPO and Raman spectroscopy, were produced by controlling the steam injection rate. The largest yield for LOPE was obtained at 0 g h(-1) steam injection rate, whilst PP and PS gave their largest yields at 0.25 gh(-1). Overall the largest CNT yield was obtained for PS at 0.25 g h(-1), with a conversion rate of plastic to CNTs of 32 wt%. (C) 2013 Elsevier B.V. All rights reserved.