Abstract This paper presents an experimental study of argan nut shell (ANS) combustion in a lab-scale furnace. Biomass composition, properties and microstructures were determined. Combustion behaviour, fuel burn rate (FBR), pollutants (CO and NOx), modified combustion efficiency (MCE) and ash analysis were investigated. A comparison with wood pellets (WP) complying with the ENplus Standard was performed. The impacts of air flow rate and particle sizes on the combustion characteristics were analysed and discussed using three average ANS particle lengths: 5–8 mm, 10–18 mm and 25–30 mm. The results show that the smallest length of ANS particles induced a higher FBR and a regular distribution of the flame shapes compared to the other sizes and to wood pellets. Furthermore, the combustion temperatures, CO emission and MCE values were improved with the highest air flow rate used. CO emission was strongly affected by the operating conditions while NOx was very low for all selected cases. Elemental ash composition reveals that no ash agglomeration was observed during experiments in terms of alkali index. Moreover, the obtained ash was in the form of powder instead of agglomerated particles. This experimental investigation improves the understanding of the operational characteristics and the combustion effect of ANS biomass.

中文翻译：

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摩洛哥坚果壳（ANS）生物质燃烧及污染物排放特性

摘要 本文介绍了在实验室规模的熔炉中对摩洛哥坚果壳 (ANS) 燃烧进行的实验研究。确定了生物质组成、性质和微观结构。研究了燃烧行为、燃料燃烧率 (FBR)、污染物（CO 和 NOx）、改进的燃烧效率 (MCE) 和灰分分析。与符合 ENplus 标准的木屑颗粒 (WP) 进行了比较。使用三种平均 ANS 颗粒长度来分析和讨论空气流速和颗粒尺寸对燃烧特性的影响：5-8 毫米、10-18 毫米和 25-30 毫米。结果表明，与其他尺寸和木屑颗粒相比，最小长度的 ANS 颗粒诱导了更高的 FBR 和火焰形状的规则分布。此外，燃烧温度、CO 排放和 MCE 值随着使用的最高空气流速而得到改善。CO 排放受操作条件的影响很大，而所有选定情况下的 NOx 都非常低。元素灰分组成表明，就碱指数而言，在实验过程中没有观察到灰团聚。此外，所获得的灰分呈粉末形式而不是附聚颗粒。这项实验研究提高了对 ANS 生物质的运行特性和燃烧效果的理解。所获得的灰分呈粉末状而不是团块状。这项实验研究提高了对 ANS 生物质的运行特性和燃烧效果的理解。所获得的灰分呈粉末状而不是团块状。这项实验研究提高了对 ANS 生物质的运行特性和燃烧效果的理解。