Hydrogen from scrap tyre oil via steam reforming and chemical looping in a packed bed reactor
Hydrogen from scrap tyre oil via steam reforming and chemical looping in a packed bed reactor
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DOI：
10.1016/j.apcatb.2012.07.010
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发表时间：
2012-09
影响因子：
22.1
通讯作者：
N. Giannakeas;A. Lea-Langton;V. Dupont;M. Twigg
中科院分区：
文献类型：
--
作者：
N. Giannakeas;A. Lea-Langton;V. Dupont;M. Twigg
研究了利用催化蒸汽重整从废轮胎热解油（STPO）中生产氢气。 STPO 的硫含量高、有机成分复杂、酸性和粘度高，容易导致催化剂失活，因此很难升级为更清洁的燃料。通过对 STPO 中已知存在的主要芳香族、脂肪族以及杂氮和硫化合物的热力学平衡计算，研究了温度和蒸汽与碳比率的影响。采用 Ni/Al2O3 催化剂、常压、蒸汽与碳摩尔比为 4:1 的填充床反应器中的最佳操作条件为 750°C，WHSV 为 0.82h−1。最大氢气产率为 STPO 原料的 26.4wt%，相当于最大理论产率的 67%，而相同条件下 22 种 STPO 化合物的模型混合物在平衡时的预测值为 79.4%。含氢产物的选择性分别为 98% H2 和 2% CH4，表明几乎没有不期望的副产物形成，并且与平衡值相当。通过化学循环重整 (CLR) 的可行性测试，探索了优化工艺以进一步提高氢气产量的潜力，旨在降低 STPO 制氢的加热和纯化成本。然而，氢气产率随着 CLR 的每次循环而下降。对催化剂的分析表明，这很可能是由于油中原本存在的碳积累和硫以及微量元素（Ca、Na）造成的失活所致。 STPO 的 CLR 后，催化剂中的 NiO 颗粒也出现了生长。因此，进一步的开发需要对油进行预处理以去除硫，并使用更耐受碳形成的催化剂。
The production of hydrogen from scrap tyre pyrolysis oil (STPO) was investigated using catalytic steam reforming. STPO is difficult to upgrade to cleaner fuels due to its high sulphur content, complex organic composition, acidity and viscosity, which contribute to catalyst deactivation. The effects of temperature and steam to carbon ratio were investigated through thermodynamic equilibrium calculations of the main aromatic, aliphatic and hetero-N and -S compounds known to be present in STPO. The optimum operating conditions in a packed bed reactor with a Ni/Al2O3catalyst at atmospheric pressure and molar steam to carbon ratio of 4:1 were 750°C at a WHSV of 0.82h−1. The maximum hydrogen yield was 26.4wt% of the STPO feedstock, corresponding to 67% of the maximum theoretical yield, compared to 79.4% predicted at equilibrium for a model mixture of 22 STPO compounds in the same conditions. The selectivity to the H-containing products was 98% H2and 2% CH4, respectively, indicating little undesirable by-product formation, and comparable to equilibrium values. The potential to optimize the process to enhance further the H2yield was explored via feasibility tests of chemical looping reforming (CLR) aimed at lowering the heating and purification costs of the hydrogen production from STPO. However, the hydrogen yield decreased with each cycle of CLR. Analysis of the catalyst indicated this was most likely due to deactivation by carbon accumulation and sulphur originally present in the oil, and possibly also by trace elements (Ca, Na). The NiO particles in the catalyst were also shown to have grown after CLR of STPO. Hence further development would require pre-treating the oil for removal of sulphur, and use of a catalyst more tolerant to carbon formation.