Producing clean energy from waste biomass via pyrolysis is critical in reducing dependence on fossil fuels and alleviating their environmental impacts. Inherent potassium in low energy density coconut fibers reduces bio-oil yield and compromises bio-oil quality and the integrity of reactors within which pyrolysis occurs. The effect of consecutive hydrothermal treatment (180°C-220 °C) and water washing on coconut fiber demineralization, pyrolysis behavior, and bio-oil composition was investigated. Chemical fractionation method classified the most occurring inorganic (potassium) as ~76% water-soluble, ~19% ion-exchangeable, and ~5% acid-soluble species. Demineralization results show that combined pretreatment at ≤200 °C leached out all water-soluble and exchangeable potassium. However, at 220 °C, electrostatic attraction and increased tortuosity imposed by the high density of oxygenated functional groups and a well-developed porous structure hamper demineralization. Nevertheless, a maximum potassium removal efficiency of 95% could be achieved. Although pretreatment marginally affects apparent activation energy, the reaction mechanism of hydrochars became insensitive to the heating rate between 10 and 50 °C min⁻¹. Due to pretreatment, the selectivity of thermally stable phenolic and anhydrosugar derivatives increased at the expense of the light oxygenates of low thermal stability because of suppressing fragmentation reactions and enriching polymers with a high degree of polymerization. Light oxygenates decreased from 27.45 area % to 24.02, 16.33, and 13.32 area % for hydrochars produced at 180 °C, 200 °C, and 220 °C, respectively. Therefore, this pretreatment approach can produce inorganic-free, thermally stable, and chemically stable bio-oils.

通过热解从废弃生物质中生产清洁能源对于减少对化石燃料的依赖和减轻其对环境的影响至关重要。低能量密度椰子纤维中的固有钾会降低生物油产量并损害生物油质量和发生热解的反应器的完整性。研究了连续水热处理 (180°C-220°C) 和水洗对椰子纤维脱矿质、热解行为和生物油组成的影响。化学分馏方法将最常见的无机物（钾）分类为约 76% 的水溶性、约 19% 的离子交换性和约 5% 的酸溶性物质。脱盐结果表明，≤200℃的联合预处理浸出所有水溶性和可交换钾。然而，在 220 °C 时，高密度含氧官能团和发达的多孔结构所施加的静电吸引力和弯曲度增加阻碍了脱矿质。尽管如此，仍可达到 95% 的最大除钾效率。尽管预处理对表观活化能的影响很小，但氢化碳的反应机制对 10 到 50 °C min 之间的加热速率变得不敏感^-1。由于预处理，热稳定的酚类和脱水糖衍生物的选择性增加，以牺牲低热稳定性的轻质含氧化合物为代价，因为抑制了断裂反应并富集了具有高聚合度的聚合物。对于在 180 °C、200 °C 和 220 °C 下生产的加氢碳，轻质含氧物从 27.45 面积 % 分别下降到 24.02、16.33 和 13.32 面积 %。因此，这种预处理方法可以生产不含无机物、热稳定和化学稳定的生物油。