Abstract Ignition of large size coal was the basis of the design and application of Fluidized Bed (FB) and Circulating Fluidized Bed (CFB) combustion technologies. The strongly coupled gas-phase and solid-phase temperature fields in existing experimental apparatus provoked obstacles for the determination of the influence of volumetric reactions on large size coal ignition. In this study, a gas-phase temperature adjustable concentrating photothermal reactor (GTA-CPR) was developed, and the gas-phase temperature could be effectively regulated by the preheated gas flow while the solid-phase temperature was determined by the irradiation voltage. 25 experimental conditions corresponded to 5 levels of solid-phase temperatures with 5 levels of gas-phase temperatures. Enhanced volumetric reactions (by higher gas-phase temperature) led to significant decrease in ignition delay (≥50%) and prolongation of flame duration (≥1.1 times). Real-time CH4 concentration in volumetric reaction boundary was detected with Mass Spectrometry (MS), which exhibited double peaks. The first CH4 peak height decreased dramatically while the second CH4 peak height increased with the gas-phase temperature, indicating the advanced ignition and enhanced volumetric reactions. Ultimately, an ignition delay prediction model was proposed through Backward induction and the indispensable importance of volumetric reactions to coal ignition was evidenced.

中文翻译：

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在气相温度可调的浓缩光热反应器中点燃大尺寸煤：体积反应的影响

摘要 大尺寸煤的点火是流化床（FB）和循环流化床（CFB）燃烧技术设计和应用的基础。现有实验装置中强耦合的气相和固相温度场为确定体积反应对大尺寸煤点火的影响造成了障碍。本研究开发了一种气相温度可调浓缩光热反应器（GTA-CPR），通过预热气流可以有效调节气相温度，而固相温度则由辐照电压决定。25 个实验条件对应于 5 个固相温度水平和 5 个气相温度水平。增强的体积反应（通过更高的气相温度）导致点火延迟显着减少（≥50%）和火焰持续时间延长（≥1.1 倍）。使用质谱 (MS) 检测体积反应边界中的实时 CH4 浓度，显示双峰。第一个 CH4 峰高显着降低，而第二个 CH4 峰高随气相温度升高而增加，表明提前点火和增强的体积反应。最终，通过反向归纳提出了点火延迟预测模型，并证明了体积反应对煤点火不可或缺的重要性。表现出双峰。第一个 CH4 峰高显着降低，而第二个 CH4 峰高随气相温度升高而增加，表明提前点火和增强的体积反应。最终，通过反向归纳提出了点火延迟预测模型，并证明了体积反应对煤点火不可或缺的重要性。表现出双峰。第一个 CH4 峰高显着降低，而第二个 CH4 峰高随气相温度升高而增加，表明提前点火和增强的体积反应。最终，通过反向归纳提出了点火延迟预测模型，并证明了体积反应对煤点火不可或缺的重要性。