School of Engineering, RMIT University, Melbourne, 3000, Australia.
Department of Chemical Engineering, Faculty of Engineering and Science, Curtin University, 98009, Sarawak, Malaysia.
Environ Sci Pollut Res Int. 2018 Jun;25(18):17529-17539. doi: 10.1007/s11356-018-1876-7. Epub 2018 Apr 16.
The process parameters of microwave hydrothermal carbonization (MHTC) have significant effect on yield of hydrochar. This study discusses the effect of process parameters on hydrochar yield produced from MHTC of rice husk. Results revealed that, over the ranges tested, a lower temperature, lower reaction time, lower biomass to water ratio, and higher particle size produce more hydrochar. Maximum hydrochar yield of 62.8% was obtained at 1000 W, 220 °C, and 5 min. The higher heating value (HHV) was improved significantly from 6.80 MJ/kg of rice husk to 16.10 MJ/kg of hydrochar. Elemental analysis results showed that the carbon content increased and oxygen content decreased in hydrochar from 25.9 to 47.2% and 68.5 to 47.0%, respectively, improving the energy and combustion properties. SEM analysis exhibited modification in structure of rice husk and improvement in porosity after MHTC, which was further confirmed from BET surface analysis. The BET surface area increased from 25.0656 m/g (rice husk) to 92.6832 m/g (hydrochar). Thermal stability of hydrochar was improved from 340 °C for rice husk to 370 °C for hydrochar.
微波水热碳化（MHTC）的工艺参数对水热炭的产率有显著影响。本研究探讨了工艺参数对稻壳 MHTC 产生的水热炭产率的影响。结果表明，在所测试的范围内，较低的温度、较短的反应时间、较低的生物质与水的比例和较大的粒径会产生更多的水热炭。在 1000 W、220°C 和 5 分钟的条件下，获得了 62.8%的最大水热炭产率。稻壳的高位发热量（HHV）从 6.80 MJ/kg 显著提高到 16.10 MJ/kg 的水热炭。元素分析结果表明，水热炭中的碳含量从 25.9%增加到 47.2%，氧含量从 68.5%降低到 47.0%，提高了能量和燃烧性能。SEM 分析表明，MHTC 后稻壳的结构发生了变化，孔隙度得到了改善，这从 BET 表面分析进一步得到了证实。BET 比表面积从 25.0656 m/g（稻壳）增加到 92.6832 m/g（水热炭）。水热炭的热稳定性从稻壳的 340°C 提高到水热炭的 370°C。
