• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文会议>The 3rd international conference on engineering for waste and biomass valorisation. >Heavy metal retention during low temperature pyrolysis of Chromated Copper Arsenate (CCA) treated wood waste: comparison between model compounds and real CCA treated wood pyrolysis
【24h】

Heavy metal retention during low temperature pyrolysis of Chromated Copper Arsenate (CCA) treated wood waste: comparison between model compounds and real CCA treated wood pyrolysis

机译：铬酸砷酸铜（CCA）处理的木材废料在低温热解过程中的重金属保留：模型化合物与实际CCA处理的木材热解之间的比较

获取原文
获取原文并翻译 | 示例
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Lab-scale experiments have been carried out to gain more insight in the mechanisms responsible for the volatilisation of heavy metals during CCA wood waste pyrolysis. A step-wise approach has been followed, starting with mixtures of wood model compounds-lignin and glucose-and arsenic model compounds -arsenic pentoxide (As2O5) and chromium arsenate (CrAsO4)-and applying thereafter these insights to CCA wood waste pyrolysis. Samples were pyrolysed in an updraft fixed bed reactor at various gage pressures (0-5 bar) and till various temperatures (310℃-390℃). After pyrolysis the samples were analysed by inductively coupled plasma-mass spectrometry (ICP-MS), to determine the amount of heavy metals still present in the solid pyrolysis residue. Moreover a ratio method was used to calculate arsenic and chromium retentions in pyrolysed CCA wood samples in order to reduce the experimental uncertainty. Elevated pressure resulted in higher metal retentions in all model compound mixtures, except for lignin/As2O5 mixtures, while metal retentions are on average little affected by temperature in the range of 310℃ to 370℃. Arsenic retention in glucose/As2O5 mixtures is substantially higher compared to lignin/As2O5 mixtures. Probably arsenic volatilisation in As2O5 samples is mainly controlled by desorption of arsenic trioxide (As2O3) from the solid residue and subsequent entrainment by pyrolysis gasses. Average arsenic retention in lignin/CrAsO4 samples is higher compared to lignin/As2O5 mixtures but lower compared to glucose/As2O5 mixtures while CrAsO4 decomposition already starts at 310℃. Average metal retention in glucose/CrAsO4 mixtures is lower compared to glucose/As2O5 mixtures and lignin/CrAsO4 mixtures. Apparently, due to a better binding to lignin, CrAsO4 is better stabilised on the lignin pyrolysis residue. In the case of glucose, arsenic and chromium species are poorly retained in the pyrolysis residue, leading to higher metal volatilisation in glucose samples. Metal retentions during pyrolysis of real CCA wood samples are higher at higher pressure while, between 330℃ and 370℃, retention decreases with increasing temperature. In this temperature range average arsenic retention attains 94% at 0 bar and 99% at 5 bar and average chromium retention is 97% at 0 bar and 96% at 5 bar. Metal retention in CCA wood samples is higher compared to CrAsO4 experiments. This is believed to be due to better fixation of CrAsO4 to the wood substrate and due to formation of agglomerates, consisting of thermally stable compounds like calcium arsenate (Ca5(AsO4)3(OH)).
机译：已经进行了实验室规模的实验，以更深入地了解造成CCA木材废料热解过程中重金属挥发的机理。已经采取了逐步方法，从木材模型化合物-木质素和葡萄糖-以及砷模型化合物-五氧化二砷（As2O5）和砷酸铬（CrAsO4）的混合物开始，然后将这些见解应用于CCA木材废料的热解。在上升压力固定床反应器中，在不同的表压下（0-5 bar）并在不同的温度下（310℃-390℃）将样品热解。热解后，通过电感耦合等离子体质谱法（ICP-MS）分析样品，以确定固体热解残留物中仍存在的重金属含量。此外，为了减少实验的不确定性，使用比率法来计算热解CCA木材样品中的砷和铬保留量。除木质素/ As2O5混合物外，升高的压力导致所有模型化合物混合物中的金属保留都较高，而平均温度在310℃至370℃范围内，金属保留的影响很小。与木质素/ As2O5混合物相比，葡萄糖在葡萄糖/ As2O5混合物中的保留率要高得多。 As2O5样品中可能的砷挥发主要是通过从固体残留物中解吸三氧化二砷（As2O3）并随后通过热解气体夹带来控制的。木质素/ CrAsO4样品中的平均砷保留量高于木质素/ As2O5混合物，但低于葡萄糖/ As2O5混合物，而CrAsO4的分解已经开始于310℃。与葡萄糖/ As2O5混合物和木质素/ CrAsO4混合物相比，葡萄糖/ CrAsO4混合物中的平均金属保留量更低。显然，由于与木质素的更好结合，CrAsO4在木质素热解残基上的稳定性更好。对于葡萄糖，砷和铬物质很难保留在热解残留物中，从而导致葡萄糖样品中的金属挥发更高。实际CCA木材样品在高温下热解过程中的金属保留率更高，而在330℃至370℃之间，保留率随温度升高而降低。在此温度范围内，砷的平均保留率在0 bar时达到94％，在5 bar时达到99％，平均铬保留率在0 bar时达到97％，在5 bar时达到96％。与CrAsO4实验相比，CCA木材样品中的金属保留率更高。据信这是由于CrAsO4更好地固定在木材基材上，并且由于形成了由热稳定化合物（如砷酸钙（Ca5（AsO4）3（OH）））组成的附聚物。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号