Finite Element Modeling of Selective Heating in Microwave Pyrolysis of Lignocellulosic Biomass
Finite Element Modeling of Selective Heating in Microwave Pyrolysis of Lignocellulosic Biomass
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DOI：
10.2528/pierb13082502
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发表时间：
2013
影响因子：
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通讯作者：
B. Dutta;S. Dev;V. Raghavan
中科院分区：
文献类型：
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作者：
B. Dutta;S. Dev;V. Raghavan
微波热解克服了传统热解方法的缺点，有效提高了最终热解产品的质量。生物炭是该过程的最终产品之一，被认为是固碳以抵消大气二氧化碳的有效载体。掺杂剂（即炭和石墨）的介电性能在 25°– 400°C 范围内进行评估，并用于开发有限元模型 (FEM)。该模型用于耦合电磁加热、燃烧以及传热传质现象，并评估微波热解过程中木质生物质选择性加热的优势。掺杂剂的介电性能是温度的函数，温度降低到 100°C，此后保持恒定。回归分析表明，炭是比石墨更好的掺杂物质。模拟研究发现，与未掺杂的样品相比，掺杂有助于在生物质内提供更有效的传热。与石墨掺杂相比，炭掺杂产生了更好的传热，因为它产生了最大化生物炭产量的最佳温度。然后通过在定制的微波热解装置中进行的实验试验对该模型进行了验证，证实了炭掺杂更适合生物炭的最大化。 2013年8月25日收稿，2013年10月16日接受，预定日期2013年10月22日 * 通讯作者：Baishali Dutta (baishali.dutta85@gmail.com)。 2 杜塔、戴夫和拉加万
Microwave pyrolysis overcomes the disadvantages of conventional pyrolysis methods by efficiently improving the quality of final pyrolysis products. Biochar, one of the end products of this process is considered an efficient vector for sequestering carbon to offset atmospheric carbon dioxide. The dielectric properties of the doping agents (i.e., char and graphite) were assessed over the range of 25◦– 400◦C and used to develop a finite element model (FEM). This model served to couple electromagnetic heating, combustion, and heat and mass transfer phenomena and evaluated the advantages of selective heating of woody biomass during microwave pyrolysis. The dielectric properties of the doping agents were a function of temperature and decreased up to 100◦C and thereafter remained constant. Regression analysis indicated that char would be a better doping substance than graphite. The simulation study found that doping helped to provide a more efficient heat transfer within the biomass compared to non-doped samples. Char doping yielded better heat transfer compared to graphite doping, as it resulted in optimal temperatures for maximization of biochar production. The model was then validated through experimental trials in a custom-built microwave pyrolysis unit which confirmed that char doping would be better suited for maximization of biochar. Received 25 August 2013, Accepted 16 October 2013, Scheduled 22 October 2013 * Corresponding author: Baishali Dutta (baishali.dutta85@gmail.com). 2 Dutta, Dev, and Raghavan