Endocarps of the olive fruit were subjected to short-time hydrothermal carbonization (SHTC) to study the effect of temperature and holding time on the properties of hydrochars. In general, the increase of these variables improved the calorific value and the combustion properties of the hydrochars, and decreased their capacity to adsorb moisture and the ash content. The best hydrochar was produced at 225 °C for 10 min, showing maximum values of higher calorific value (23.4 MJ/kg), energy yield (74.7%), and comprehensive combustibility index (6.19 × 10^–7 min^–2 °C^–3), higher values than those were managed working at 250 °C. The increase in energy efficiency at 225 °C at longer reaction residence times was related to repolimerization phenomena studied by mean of the analysis of the structural components of the biomass (fiber analysis), scanning electron microscopy inspection, and Fourier-transform infrared spectroscopy. Finally, the pyrolysis of the olive-fruit endocarp could be mathematically modeled, from thermogravimetric analysis, concluding that this process requires higher temperatures to remove volatile materials of the biomass, in comparison with the SHTC.

中文翻译：

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短时热液碳化对橄榄果内果皮制备炭的性能的影响

对橄榄果实的内果皮进行短时热液碳化（SHTC），以研究温度和保温时间对水炭特性的影响。通常，这些变量的增加会改善水蒸气的热值和燃烧特性，并降低其吸收水分和灰分的能力。最佳水炭在225°C下产生10分钟，显示出较高的最高值（23.4 MJ / kg），较高的热值（74.7％）和综合可燃性指数（6.19×10 ^–7 min ^–2 °C ^{– 3}）的值高于在250°C下管理的值。在225°C下更长的反应停留时间下，能量效率的提高与通过生物质的结构成分分析（纤维分析），扫描电子显微镜检查和傅里叶变换红外光谱研究的再聚合现象有关。最后，通过热重分析可以对橄榄果皮的热解进行数学建模，从而得出结论：与SHTC相比，该过程需要更高的温度才能去除生物质中的挥发性物质。