Abstract In this work, water caltrop husk (WCH), a special agricultural residue in tropical and subtropical Asian countries, was used as a potential precursor for preparing torrefied biomass at different temperatures (i.e., 200, 240, 280, 320, and 360 °C) and residence times (i.e., 0, 30, 60, and 120 min). To best of our knowledge, this is currently the first study on the thermochemical characteristics of WCH-torrefied products. The mass yields and energy yields of resulting products indicated a decreasing trend with increasing temperature. By contrast, their calorific values and carbon contents generally increased at higher temperatures and longer residence times. These findings were consistently verified by the energy dispersive X-ray spectroscopy (EDS). Based on the thermochemical characteristics, the optimal WCH-torrefied product, which corresponded to mass yield of 45.2%, carbon content of 65.23%, calorific value of 25.3 MJ/kg and energy yield of 65.7%, was obtained at 320 °C for 60 min. According to the classification of solid fuels by the van Krevelen diagram, the optimal torrefied product showed a lignite-like feature. However, this lignite-like biomass fuel would not be appropriate to be directly used in boilers because of its relatively high minerals. Alternatively, it may be blended with coal in existing coal-fired power plants.

中文翻译：

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通过烘焙将菱角壳转化为烘焙生物质

摘要 在这项工作中，菱角壳（WCH）是亚洲热带和亚热带国家的一种特殊农业残留物，被用作在不同温度（即 200、240、280、320 和 360°）下制备烘焙生物质的潜在前体。 C) 和停留时间（即 0、30、60 和 120 分钟）。据我们所知，这是目前对 WCH 烘焙产品的热化学特性的首次研究。所得产物的质量产率和能量产率随温度升高呈下降趋势。相比之下，它们的热值和碳含量通常在较高温度和较长停留时间下增加。这些发现得到了能量色散 X 射线光谱 (EDS) 的一致验证。基于热化学特性，最佳WCH烘焙产品，在 320 °C 下 60 分钟，对应的质量产率为 45.2%，碳含量为 65.23%，热值为 25.3 MJ/kg，能量产率为 65.7%。根据van Krevelen图对固体燃料的分类，最佳烘焙产品表现出类似褐煤的特征。然而，这种类似褐煤的生物质燃料由于其矿物质含量相对较高，不适合直接用于锅炉。或者，它可以与现有燃煤电厂中的煤混合。这种类似褐煤的生物质燃料不适合直接用于锅炉，因为其矿物质含量相对较高。或者，它可以与现有燃煤电厂中的煤混合。这种类似褐煤的生物质燃料不适合直接用于锅炉，因为其矿物质含量相对较高。或者，它可以与现有燃煤电厂中的煤混合。