Combustion details of raw and torrefied biomass fuel particles with individually-observed size, shape and mass
Combustion details of raw and torrefied biomass fuel particles with individually-observed size, shape and mass
复制标题
DOI：
10.1016/j.combustflame.2019.06.009
复制
发表时间：
2019-09
影响因子：
4.4
通讯作者：
A. Panahi;N. Vorobiev;M. Schiemann;Mahmut Tarakcioglu;M. Delichatsios;Y. Levendis
中科院分区：
文献类型：
--
作者：
A. Panahi;N. Vorobiev;M. Schiemann;Mahmut Tarakcioglu;M. Delichatsios;Y. Levendis
采用了一种独特的方法和提出的方法，通过对暴露于高温（>1000 K）和非常高的加热速率（104-105K /s）下的小型生物质燃料颗粒的燃烧历史的详细结果，来确定木炭燃烧速率及其主要结构。类似的情况通常在发电用的粉状燃料锅炉中普遍存在。从五种不同类型的原料和碳化生物质中选择预先测量大小、形状、长径比和质量的单个颗粒进行研究。这些颗粒被注入一个透明的滴管炉，电加热到1400 K，在那里它们被迅速加热，点燃并在空气中燃烧。单个颗粒的温度-时间历史记录的高温，并用于评估他们的个别燃烧速率。这些颗粒以不同的挥发相和炭相燃烧。对已发表的含碳燃料颗粒的现象燃烧模型进行了改进，并将其应用于实验数据，计算了炭的燃烧速率。这些在挥发性物质包壳火焰中形成的炭的性质的重要信息，是通过将其原始性质的知识与高温观测和数值模拟相结合而获得的。结果表明，在这些实验条件下，大多数类型的生物质炭由薄壁微球形颗粒组成。模拟结果表明，要进行可靠的燃烬预测，需要考虑这种主要颗粒结构。
A unique approach and proposed methodology was implemented to determine char burning rates in conjunction to their prevailing structure from detailed results on the combustion histories of small biomass fuel particles, exposed to elevated temperatures (>1000 K) at very high heating rates (104–105K/s). Analogous conditions typically prevail in pulverized fuel utility boilers for power generation. Individual particles of pre-measured size, shape, aspect ratio and mass from five different types of raw and torrefied biomass were selected for this study. The particles were injected into a transparent drop-tube furnace, electrically heated to 1400 K, where they were rapidly heated, ignited and burned in air. Temperature-time histories of the individual particles were recorded pyrometrically and were used to assess their individual combustion rates. These particles burned in distinct volatile and char phases. A published phenomenological combustion model for carbonaceous fuel particles was enhanced and applied to the experimental data to calculate the char burning rates. Important information on the nature of these chars, which formed inside volatile matter envelope flames, was obtained by juxtaposition of the knowledge of their original properties with the pyrometric observations and the numerical simulations. It was concluded that, under the conditions of these experiments, chars of most types of biomass consisted of thin-wall cenospherical particles. The modeling results show that this predominant particle structure needs to be considered for reliable burnout predictions.