Abstract This work studied the changes of stable isotope compositions (C and N) of diverse biomass feedstocks (loblolly pine, cow manure, and sewage biosolids) as a result of hydrothermal carbonization (HTC), and provides insight into degradation pathways based on these changes. HTC was conducted at different times (5 and 30 min) and temperatures (180, 220, and 260 °C) and produced hydrochars were characterized in terms of ultimate, proximate, stable carbon isotope (δ 13 C), and stable nitrogen isotope (δ 15 N) compositions. In addition to reaction conditions, results showed that the differences in feedstock composition, closely related to reactivity, determined in large part isotope behavior. In general, the carbon densification associated with HTC corresponded to a small but consistent decrease of δ 13 C values. In contrast, there were significant increases of δ 15 N values during HTC, with larger shifts associated with increased HTC reaction severity. These trends in isotopic compositions, related to changes of characteristic elemental indices (O/C, H/C, O/N, H/N), allowed for the identification of particular reaction pathways for individual feedstocks.

中文翻译：

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生物质水热碳化过程中稳定碳和稳定氮同位素的行为

摘要 这项工作研究了不同生物质原料（火炬松、牛粪和污水生物固体）的稳定同位素组成（C 和 N）由于热液碳化 (HTC) 的变化，并提供了基于这些变化的降解途径的见解。 . HTC 在不同的时间（5 和 30 分钟）和温度（180、220 和 260 °C）下进行，并根据最终、近似、稳定的碳同位素（δ 13 C）和稳定的氮同位素（ δ 15 N) 组成。除了反应条件外，结果表明，与反应性密切相关的原料组成的差异在很大程度上决定了同位素行为。一般而言，与 HTC 相关的碳致密化对应于 δ 13 C 值的小而一致的下降。相比之下，在 HTC 期间，δ 15 N 值显着增加，较大的变化与 HTC 反应严重程度的增加有关。同位素组成的这些趋势与特征元素指数（O/C、H/C、O/N、H/N）的变化有关，可以识别单个原料的特定反应途径。