As a by-product of the rapid pyrolysis of biomass, biochar not only plays an important role in the biomass conversion process but also holds significant potential value in the catalytic conversion field. This study aimed to evaluate the physicochemical properties changes of biochars at different pyrolysis temperatures and their potential application in tar reforming. Biochars derived from three feedstocks of maize straw (MS), rice husk (RH), and cotton straw (CS) were achieved by fast pyrolysis within a broad temperature range of 300–900 °C, respectively. The results showed that the pyrolysis temperature exerted a pronounced influence on the structural characteristics of biochar. With increasing temperature, the H/C and O/C ratios progressively decreased, accompanied by a significant reduction in oxygen-containing structures. In addition, elevated pyrolysis temperatures contributed favorably to the formation of the crystalline structure of biochar. Raman analysis unveiled a correlation between the fused aromatic ring system and H/C ratios, validating the aromatization progress of biochar. In the tar catalytic reforming process, the three representative biochars, under the effect of MS-600 (standing for MS biochar derived at 600 °C), RH-600, and CS-600 catalysts, exhibited outstanding catalytic performance with tar conversion efficiencies of 73.26%, 68.51%, and 71.43%, respectively. This study provided systematic support for the high-value use of biochar from crop straw.

中文翻译：

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不同热解温度对农作物秸秆生物炭理化特性的影响及其在焦油重整中的应用

生物炭作为生物质快速热解的副产品，不仅在生物质转化过程中发挥着重要作用，而且在催化转化领域具有重要的潜在价值。本研究旨在评估不同热解温度下生物炭的物理化学性质变化及其在焦油重整中的潜在应用。分别从玉米秸秆（MS）、稻壳（RH）和棉秆（CS）三种原料中通过在 300-900 °C 的宽温度范围内快速热解获得生物炭。结果表明，热解温度对生物炭的结构特征有显着影响。随着温度升高，H/C和O/C比率逐渐降低，同时含氧结构显着减少。此外，升高的热解温度有利于生物炭晶体结构的形成。拉曼分析揭示了稠合芳环体系与 H/C 比率之间的相关性，验证了生物炭的芳构化进程。在焦油催化重整过程中，三种具有代表性的生物炭在MS-600（代表600℃下生成的MS生物炭）、RH-600和CS-600催化剂的作用下，表现出优异的催化性能，焦油转化效率为分别为 73.26%、68.51% 和 71.43%。该研究为农作物秸秆生物炭的高值化利用提供了系统支撑。