Thermal Decomposition Behavior of Loblolly Pine Stemwood, Bark, and Limbs/Foliage Using TGA And DSC Techniques
Thermal Decomposition Behavior of Loblolly Pine Stemwood, Bark, and Limbs/Foliage Using TGA And DSC Techniques
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使用 TGA 和 DSC 技术研究火炬松茎材、树皮和枝条/叶子的热分解行为
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发表时间：
2015
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影响因子：
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通讯作者：
S. Adhikari
中科院分区：
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作者：
K. Owen;O. Fasina;Steven Taylor;S. Adhikari
收获前，一棵直立的树有三个主要组成部分：树皮、树枝/树叶和树干。由于各种原因，森林生物质能源潜力的开发工作大多使用树干(也称为清洁碎屑)作为原料。然而，树木的树皮和树枝/树叶的数量很大(按质量计算约为25%)，可能会影响森林转化为生物能源过程的经济。在本研究中，研究了这三种主要组分在氮气和空气中的升温速率为5℃~20℃min-1时的热分解速度和动力学。其平均质量分数分别为：干材74.6%，枝条/叶18.2%，树皮7.2%。干材组分的灰分最低(0.32%，D.B.)挥发物含量最高(85.6%，D.B.)内容。当样品在氮气气氛中热分解时，每个组分的样品质量(根据样品类型而定，为原始质量的40%至60%)在150℃至425℃之间发生重大损失。在空气中，在150°C到600°C的温度范围内，几乎所有样品的非灰分都挥发掉了。树干木材的活化能比低挥发分含量的树皮和树枝/树叶至少低20%。样品在空气气氛中热分解的活化能高于在氮气气氛中的相应活化能。
A standing tree before harvest has three primary components: bark, limbs/foliage, and stemwood. For a variety of reasons, most of the development work on forest biomass energy potential has used stemwood (also known as clean chips) as the feedstock. However, the amount of bark and limbs/foliage in a tree is significant (around 25% on mass basis) and may influence the economics of the forest-to-bioenergy process. In this study, the rate and kinetics of thermal decomposition of these three primary components were studied at heating rates of 5°C to 20°C min -1 in both nitrogen and air atmospheres. The average mass fractions of the components were 74.6% stemwood, 18.2% limbs/foliage, and 7.2% bark. The stemwood component significantly had the lowest ash (0.32%, d.b.) and highest volatile matter (85.6%, d.b.) contents. Major loss in sample mass (40% to 60% of original mass depending on sample type) of each component occurred between 150°C and 425°C when the samples were thermally decomposed in nitrogen atmosphere. In air atmosphere, virtually all of the non-ash component of each sample was volatilized within the temperature range of 150°C to 600°C. The activation energies of stemwood were at least 20% lower than those of the low volatile matter content bark and limbs/foliage. The activation energies for the samples thermally decomposed in air atmosphere were higher than the corresponding values for nitrogen atmosphere.