On the particle sizing of torrefied biomass for co-firing with pulverized coal
On the particle sizing of torrefied biomass for co-firing with pulverized coal
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DOI：
10.1016/j.combustflame.2018.04.014
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发表时间：
2018-08-01
影响因子：
4.4
通讯作者：
Levendis, Yiannis A.
中科院分区：
文献类型：
--
作者：
Panahi, Aidin;Tarakcioglu, Mahmut;Levendis, Yiannis A.
在生物质收获和燃料制备过程中，研磨会导致显著的能源消耗惩罚，从而导致类似的成本影响。这是由于生物质的纤维性和坚韧性。生物质的焙烧使其变脆，因为它减少了其纤维性质，因此增强了其可磨性。然而，研磨成本仍然很重要，并且随着目标粒度的减小而增加。因此，本研究介绍了一种评估现有煤粉燃料锅炉中适用于燃烧或与煤共烧的碳化生物质磨粉粒度的方法。它检查燃烧生物质的不同来源，草本，木本，或作物相关。生物质在275℃的氮气中固化30分钟。随后，它被磨碎并筛选成各种尺寸的切割，这反映了这些典型的细长颗粒的平均宽度而不是长度。随后，颗粒在降管炉（DTF）中在高温和高升温速率条件下一次一个地燃烧。用热计法和电影摄影法观察了不同尺寸切口的许多单个粒子的发光燃烬时间。然后将其与75 ~ 90 μ m的单个煤颗粒（即燃煤锅炉燃烧颗粒的上端）的燃尽时间进行对比。基于这一比较，所研究的碳化生物质颗粒的公称筛孔尺寸为212-300 μ m，其总体观察到的燃尽时间与75-90 μ m煤颗粒的燃烧时间相匹配。因此，为了使现有锅炉中这种碳化生物质与煤共烧的粉碎成本最小化，可能不需要对其进行更细的粉碎。(C) 2018燃烧研究所。Elsevier Inc.出版。版权所有。
In biomass harvesting and fuel preparation processes, grinding causes a prominent energy consumption penalty, which results in an analogous cost impact. This is due to the fibrous and tenacious nature of biomass. Torrefaction of biomass makes it brittle, as it diminishes its fibrous nature and, hence, it enhances its grindability. Nevertheless, grinding costs are still important and increase with decreasing targeted particle size. Therefore, this study introduces a methodology for assessing the torrefied biomass grind size that is suitable for firing or co-firing with coal in existing pulverized fuel boilers. It examines combustion of biomass of different origins, herbaceous, woody, or crop-related. Biomass was torrefied for 30 min at 275 degrees C in nitrogen. It was subsequently ground and sieved to various size cuts, which reflect the mean widths rather than the lengths of these typically elongated particles. Subsequently, the particles were burned, one at a time, in a drop tube furnace (DTF) under high temperature and high heating rate conditions. Luminous burnout times were observed pyrometrically and cinematographically for a number of single particles from various size cuts. Such burnout times were then contrasted with those of individual coal particles in the size range of 75-90 mu m, i.e., at the upper end of particle sizes burned in coal-fired boilers. Based on this comparison, the nominal sieve size of the examined torrefied biomass particles whose overall observed burnout times matched those of the 75-90 mu m coal particles was determined to be 212-300 mu m. Hence, to minimize the grinding cost of co-firing such torrefied biomass with coal in existing boilers, its finer pulverization may not be necessary. (C) 2018 The Combustion Institute. Published by Elsevier Inc. All rights reserved.