Miyawaki Nozomi, Fukushima Takashi, Mizuno Takafumi, Inoue Miyao, Takisawa Kenji
Graduate School of Bioresources, Mie University, 1577 Kurimamachiyacho, Tsu, Mie, 514-8507, Japan.
Faculty of Home Economics, Tokyo Kasei University, 1-18-1 Kaga, Itabashi, Tokyo, 173-8602, Japan.
Bioresour Bioprocess. 2021 Feb 27;8(1):21. doi: 10.1186/s40643-021-00373-7.
Biomass may ignite due to biological oxidation and chemical oxidation. If this phenomenon (spontaneous ignition) is controlled, it would be possible to produce biochar at a lower cost without the need for an external heat resource. We investigated if self-heating could be controlled by using sawdust and bark chips. When sawdust and bark chips were used under controlled conditions, the bark chips temperature increased to the torrefaction temperature. The ash content of bark chips was ~ 2%d.b. higher than that of sawdust; consequently, the inorganic substances contained in the bark chips might affect the self-heating. Self-heating was suppressed when inorganic substances were removed by washing with water. Therefore, the inorganic substances in the biomass might have affected self-heating. The inorganic element contents of the bark chips were measured by inductively coupled plasma optical emission spectrometry before and after washing. The potassium content of the bark chips was reduced remarkably by washing, and there was a possible influence of potassium on self-heating. Finally, the effect of moisture content on self-heating was investigated to obtain stable reactivity. Thus, at a moisture content of 40%w.b., a steady self-heating behavior may be realized.
生物质可能由于生物氧化和化学氧化而着火。如果能控制这种现象（自燃），就有可能在无需外部热源的情况下以较低成本生产生物炭。我们研究了是否可以通过使用锯末和树皮碎片来控制自热。在受控条件下使用锯末和树皮碎片时，树皮碎片的温度升高到了烘焙温度。树皮碎片的灰分含量比锯末高约2%（干基）；因此，树皮碎片中所含的无机物可能会影响自热。通过水洗去除无机物后，自热受到抑制。所以，生物质中的无机物可能影响了自热。在水洗前后，通过电感耦合等离子体发射光谱法测量了树皮碎片的无机元素含量。水洗后树皮碎片的钾含量显著降低，钾可能对自热有影响。最后，研究了水分含量对自热的影响以获得稳定的反应性。因此，在水分含量为40%（湿基）时，可能实现稳定的自热行为。
