Self-heating during storage of biomass in piles causes material losses, leads to emissions to air, and poses a risk of fire. There are different techniques to assess a biomass material's propensity for self-heating, some of these are briefly reviewed. One of these techniques is isothermal calorimetry, which measures thermal power from materials and produces time-resolved curves. A recently developed and published test standard, ISO 20049-1:2020, describes how the self-heating of pelletized biofuels can be determined by means of isothermal calorimetry and how thermal power and the total heat produced during the test should be measured by isothermal calorimetry. This paper supports interpretation of the result obtained by isothermal calorimetry; the mentioned standard provides examples of peak thermal power and total heat but does not provide any assistance on how the result from isothermal measurements should be interpreted or how the result from measurements on different samples could be compared. This paper addresses the impact of different types of reactions, peak thermal power, total heat released (heat of reaction), activation energy, heat conductivity, and pile size on the temperature development in a generic pile of biomass. This paper addresses important parameters when the result from isothermal calorimetry is evaluated. The most important parameter, with respect to temperature development in large piles, was found to be the total heat released. It was also proposed that safe storage times, that is, the time until a run-away of the temperature in the pile, could be ranked based on the time to the peak thermal power.

中文翻译：

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反应类型对生物质堆中产热和材料损失影响的理论评估

生物质堆存期间的自热会导致材料损失，导致排放到空气中，并造成火灾风险。有不同的技术来评估生物质材料的自加热倾向，其中一些技术进行了简要回顾。其中一种技术是等温量热法，它测量材料的热功率并生成时间分辨曲线。最近制定和发布的测试标准 ISO 20049-1:2020 描述了如何通过等温量热法测定颗粒状生物燃料的自热性，以及如何通过等温量热法测量测试过程中产生的热功率和总热量。本文支持对等温量热法所得结果的解释；上述标准提供了峰值热功率和总热量的示例，但没有就如何解释等温测量结果或如何比较不同样品的测量结果提供任何帮助。本文讨论了不同类型的反应、峰值热功率、释放的总热量（反应热）、活化能、热导率和堆尺寸对一般生物质堆中温度发展的影响。本文讨论了评估等温量热法结果时的重要参数。人们发现，就大堆的温度发展而言，最重要的参数是释放的总热量。还提出可以根据达到峰值热功率的时间对安全存储时间（即堆内温度失控之前的时间）进行排序。