Nhuchhen Daya Ram, Afzal Muhammad T
Mechanical Engineering Department, University of New Brunswick, Fredericton, NB E3B 5A3, Canada.
Bioengineering (Basel). 2017 Jan 24;4(1):7. doi: 10.3390/bioengineering4010007.
Many correlations are available in the literature to predict the higher heating value (HHV) of raw biomass using the proximate and ultimate analyses. Studies on biomass torrefaction are growing tremendously, which suggest that the fuel characteristics, such as HHV, proximate analysis and ultimate analysis, have changed significantly after torrefaction. Such changes may cause high estimation errors if the existing HHV correlations were to be used in predicting the HHV of torrefied biomass. No study has been carried out so far to verify this. Therefore, this study seeks answers to the question: "Can the existing correlations be used to determine the HHV of the torrefied biomass"? To answer this, the existing HHV predicting correlations were tested using torrefied biomass data points. Estimation errors were found to be significantly high for the existing HHV correlations, and thus, they are not suitable for predicting the HHV of the torrefied biomass. New correlations were then developed using data points of torrefied biomass. The ranges of reported data for HHV, volatile matter (VM), fixed carbon (FC), ash (ASH), carbon (C), hydrogen (H) and oxygen (O) contents were 14.90 MJ/kg-33.30 MJ/kg, 13.30%-88.57%, 11.25%-82.74%, 0.08%-47.62%, 35.08%-86.28%, 0.53%-7.46% and 4.31%-44.70%, respectively. Correlations with the minimum mean absolute errors and having all components of proximate and ultimate analyses were selected for future use. The selected new correlations have a good accuracy of prediction when they are validated using another set of data (26 samples). Thus, these new and more accurate correlations can be useful in modeling different thermochemical processes, including combustion, pyrolysis and gasification processes of torrefied biomass.
文献中有许多关联式可用于通过元素分析和工业分析来预测原生生物质的高位发热量（HHV）。关于生物质烘焙的研究正在迅猛发展，这表明燃料特性，如高位发热量、元素分析和工业分析，在烘焙后发生了显著变化。如果使用现有的高位发热量关联式来预测烘焙生物质的高位发热量，这些变化可能会导致较高的估计误差。到目前为止，尚未有研究对此进行验证。因此，本研究旨在回答以下问题：“现有的关联式能否用于确定烘焙生物质的高位发热量？”为了回答这个问题，使用烘焙生物质数据点对现有的高位发热量预测关联式进行了测试。结果发现，现有的高位发热量关联式的估计误差非常高，因此，它们不适用于预测烘焙生物质的高位发热量。然后，利用烘焙生物质的数据点建立了新的关联式。报告的高位发热量、挥发物（VM）、固定碳（FC）、灰分（ASH）、碳（C）、氢（H）和氧（O）含量的数据范围分别为14.90 MJ/kg - 33.30 MJ/kg、13.30% - 88.57%、11.25% - 82.74%、0.08% - 47.62%、35.08% - 86.28%、0.53% - 7.46%和4.31% - 44.70%。选择了具有最小平均绝对误差且包含元素分析和工业分析所有组分的关联式以供未来使用。当使用另一组数据（26个样本）进行验证时，所选的新关联式具有良好的预测准确性。因此，这些新的、更准确的关联式可用于模拟不同的热化学过程，包括烘焙生物质的燃烧、热解和气化过程。
