Abstract To study the role of gasifying agents (H 2 O/CO 2 ) on the improvement and maintenance of biochar catalytic activity for in situ biomass tar reforming, experiments were carried out in a two-stage fluidized-bed/fixed-bed reactor. The physicochemical properties of biochar, which are responsible for its catalytic activity during tar reforming, were analyzed by ICP–AES, SEM–EDX, BET and XPS methods. The conversion of biomass tar was investigated by GC–MS. Adding H 2 O or CO 2 was found to improve the homogeneous and heterogeneous reforming of biomass tar, the latter of which involved first forming an intermediary coke product that was subsequently gasified by H 2 O/CO 2 . Activation of biochar by H 2 O/CO 2 impacted the biochar surface's morphology and distribution of metal species. During tar reforming, the presence of H 2 O/CO 2 also affected the creation and regeneration of pore structures, influencing the biochar's structure and dynamically distributing AAEM species, which ensured enough surface active sites to maintain the biochar's catalytic activity. CO 2 produced more micropores in the biochar, whereas H 2 O favored the formation of mesopores, which are more important for tar reforming. The addition of H 2 O/CO 2 was found to notably enhance in situ reforming of both large and small aromatic ring systems in biomass tar over biochar.

中文翻译：

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生物炭在热解和 H 2 O/CO 2 气化过程中原位生物质焦油重整的催化活性的提高和维持

摘要 为研究气化剂（H 2 O/CO 2 ）对生物质焦油原位重整生物炭催化活性的提高和维持作用，在两级流化床/固定床反应器中进行了实验。通过 ICP-AES、SEM-EDX、BET 和 XPS 方法分析了生物炭的理化性质，这在焦油重整过程中起催化作用。通过GC-MS研究生物质焦油的转化。发现添加 H 2 O 或 CO 2 可以改善生物质焦油的均质和非均质重整，后者首先形成中间焦炭产品，然后由 H 2 O/CO 2 气化。H 2 O/CO 2 对生物炭的活化影响了生物炭表面的形态和金属种类的分布。在焦油重整过程中，H 2 O/CO 2 的存在也影响了孔隙结构的产生和再生，影响了生物炭的结构和动态分布的AAEM物种，这确保了足够的表面活性位点来维持生物炭的催化活性。CO 2 在生物炭中产生更多的微孔，而 H 2 O 有利于形成对焦油重整更重要的中孔。发现添加 H 2 O/CO 2 显着增强了生物质焦油中大和小芳环系统在生物炭上的原位重整。而 H 2 O 有利于形成对焦油重整更重要的中孔。发现添加 H 2 O/CO 2 显着增强了生物质焦油中大和小芳环系统的原位重整优于生物炭。而 H 2 O 有利于形成对焦油重整更重要的中孔。发现添加 H 2 O/CO 2 显着增强了生物质焦油中大和小芳环系统在生物炭上的原位重整。