Investigations into the effects of volatile biomass tar on the performance of Fe-based CLC oxygen carrier materials
Investigations into the effects of volatile biomass tar on the performance of Fe-based CLC oxygen carrier materials
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DOI：
10.1088/1748-9326/11/11/115001
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发表时间：
2016-11-01
影响因子：
6.7
通讯作者：
Fennell, Paul S.
中科院分区：
文献类型：
--
作者：
Boot-Handford, Matthew E.;Florin, Nick;Fennell, Paul S.
在这项研究中，我们展示了对生物质焦油与两种设计用于化学环应用的铁基氧载体材料（OCM）之间相互作用的研究结果：100% Fe2O3 (100Fe) OCM和60 wt% Fe2O3/40 wt% Al2O3 (60Fe40Al) OCM。设计并建造了一种新型的6 kW(e)两级固定床反应器，用于模拟生物质非原位气化的化学环燃烧（CLC）过程。在第一级反应器中，山毛榉木材在773 K下进行热解，产生含焦油的燃料气体，用于减少在973 K下装载到第二级的OCM。与将生物质焦油化合物暴露于惰性砂床的类似实验相比，发现任何一种OCM的存在都可显着减少出反应器的生物质焦油量，最多可减少71%。60Fe40Al OCM的焦油裂解效应略大于100Fe OCM，尽管与100Fe OCM相比，60Fe40Al OCM所观察到的焦油收率的降低大致相当于碳沉积的增加。在这两种情况下，OCM的焦油裂解效果似乎与OCM暴露于挥发性生物质热解产物（即Fe2O3或Fe3O4）的氧化状态无关。将热解蒸汽暴露于氧化态（Fe2O3）的ocm中有利于CO2的生成。当ocm处于还原态（Fe3O4）时，有利于CO的生成。碳沉积在随后的氧化阶段被去除，在随后的3 mol% CO还原的CLC循环中对反应活性没有明显的有害影响。
In this study we present findings from investigations into interactions between biomass tar and two iron based oxygen carrier materials (OCMs) designed for chemical-looping applications: a 100% Fe2O3 (100Fe) OCM and a 60 wt% Fe2O3/40 wt% Al2O3 (60Fe40Al) OCM. A novel 6 kW(e) two-stage, fixed-bed reactor was designed and constructed to simulate a chemical-looping combustion (CLC) process with ex situ gasification of biomass. Beech wood was pyrolysed in the first stage of the reactor at 773 K to produce a tar-containing fuel gas that was used to reduce the OCM loaded into the 2nd stage at 973 K. The presence of either OCM was found to significantly reduce the amount of biomass tars exiting the reactor by up to 71 wt% compared with analogous experiments in which the biomass tar compounds were exposed to an inert bed of sand. The tar cracking effect of the 60Fe40Al OCM was slightly greater than the 100Fe OCM although the reduction in the tar yield was roughly equivalent to the increase in carbon deposition observed for the 60Fe40Al OCM compared with the 100Fe OCM. In both cases, the tar cracking effect of the OCMs appeared to be independent of the oxidation state in which the OCM was exposed to the volatile biomass pyrolysis products (i.e. Fe2O3 or Fe3O4). Exposing the pyrolysis vapours to the OCMs in their oxidised (Fe2O3) form favoured the production of CO2. The production of CO was favoured when the OCMs were in their reduced (Fe3O4) form. Carbon deposition was removed in the subsequent oxidation phase with no obvious deleterious effects on the reactivity in subsequent CLC cycles with reduction by 3 mol% CO.