Hydrothermal treatment (HT) is a promising thermal conversion technology that can convert wastes with high moisture content into value-added products. The effects of reaction time on the dewatering performance and product characteristics of oily scum were investigated through HT in this study. The main components in liquid and the combustion characteristics of hydrochars were also studied. Results showed that as the HT reaction time increased, the appearance of the liquid product changed from light yellow clarifying solution to yellow turbidity oil-water mixture. The liquid yield obtained from the HT process of oily scum increased with the increase of reaction time, while the moisture yield in hydrochars decreased gradually. The increase of reaction time improved the filtration performance and dewaterability of oily scum. Hydrochars presented the microscopic properties of the smooth and rough surfaces as well as the particles with different sizes. The thermogravimetric analysis showed that the devolatilization and combustion process of hydrochars was further separated into the two combustion phases of light and heavy volatiles. The combustion process of hydrochars was easier than dried oily scum due to lower activation energy and pre-exponential factor. The results obtained in this study could provide valuable references for the reasonable treatment and effective utilization of oily scum.

中文翻译：

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水热处理延长反应时间下油性浮渣脱水性能及产物特性的实验研究

水热处理（HT）是一种很有前途的热转化技术，可以将高水分含量的废物转化为增值产品。本研究通过 HT 研究了反应时间对油性浮渣脱水性能和产品特性的影响。还研究了液体中的主要成分和水炭的燃烧特性。结果表明，随着HT反应时间的增加，液体产物的外观由淡黄色澄清液变为黄色浑浊油水混合物。油性浮渣HT工艺的液体收率随着反应时间的增加而增加，而水炭中的水分收率逐渐降低。反应时间的增加提高了油性浮渣的过滤性能和脱水性。Hydrochars 呈现了光滑和粗糙表面以及不同尺寸颗粒的微观性质。热重分析表明，水炭的脱挥和燃烧过程进一步分为轻挥发物和重挥发物两个燃烧阶段。由于较低的活化能和指前因子，水炭的燃烧过程比干燥的油状浮渣更容易。本研究结果可为油性浮渣的合理处理和有效利用提供有价值的参考。热重分析表明，水炭的脱挥和燃烧过程进一步分为轻挥发物和重挥发物两个燃烧阶段。由于较低的活化能和指前因子，水炭的燃烧过程比干燥的油状浮渣更容易。本研究结果可为油性浮渣的合理处理和有效利用提供有价值的参考。热重分析表明，水炭的脱挥和燃烧过程进一步分为轻挥发物和重挥发物两个燃烧阶段。由于较低的活化能和指前因子，水炭的燃烧过程比干燥的油状浮渣更容易。本研究结果可为油性浮渣的合理处理和有效利用提供有价值的参考。