Conversion of manure into energy products via hydrothermal liquefaction was studied. Hydrothermal reactions, conducted at different temperatures (200–300 °C), were compared on the basis of conversion yields, carbon and energy recoveries and product quality. The results demonstrate how reaction temperatures affect the relative production of biocrude oil and hydrochar. Comprehensive analyses of both biocrude oil and hydrochar suggest that decarboxylation was the dominant mechanism involved in the reaction and was enhanced with temperature. With a relatively high carbon (67–74%) and low oxygen (13–18%) content, biocrude oil seems to provide a better platform to deliver recovered energy, with higher heating values of 30–35 MJ kg⁻¹. An overall energy balance, supported by a sensitivity analysis, demonstrated how the higher temperature enhanced the overall energy return. Twelve scenarios were used to estimate the daily net energy gained in feedlots of different sizes. All scenarios provided a positive energy balance with returned energy found to be 2 to 3 times higher than invested energy. The estimation presented herein highlights the feasibility of hydrothermal technology to return energy by multiple products and, hence, to provide a sustainable waste management practice in confined feedlots.

中文翻译：

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肉牛粪便的水热转化可提高密闭饲养场的能量回收

研究了通过水热液化将粪便转化为能源产品的过程。根据转化率，碳和能量回收率以及产品质量，比较了在不同温度（200–300°C）下进行的水热反应。结果表明反应温度如何影响生物原油和水焦油的相对产量。对生物原油和烃的综合分析表明，脱羧是反应的主要机理，并随温度的升高而增强。具有相对较高的碳含量（67-74％）和较低的氧气含量（13-18％），生物原油似乎提供了一个更好的平台来提供回收的能量，具有更高的热值30-35 MJ kg ^-1。通过灵敏度分析支持的总体能量平衡表明，较高的温度如何提高总体能量返回。十二种情况被用来估计不同大小的饲养场每天获得的净能量。所有方案都提供了积极的能量平衡，并且返回的能量比投资的能量高出2至3倍。本文提出的估算结果突出了水热技术通过多种产品返回能量并因此在密闭饲养场中提供可持续废物管理实践的可行性。