流化床煤气化技术因具有良好的混合与传热性能被广泛应用于煤化工领域。流化床内气固混合剧烈，高温将导致排灰残留大量碳。传统流化床气化采用低温操作降低灰渣含碳量，但相应气化效率不足。为此，研究人员提出灰熔聚流化床气化技术，通过煤灰有限度的团聚增加床层温度。团聚体尺寸是灰熔聚流化床气化的关键参数，因此需对颗粒团聚过程进行研究。灰熔聚气化炉内颗粒运动情况复杂，仅用实验方式进行分析会付出高昂成本，需结合反应器数学建模实现高效研究。然而，现有灰熔聚流化床气化炉数学模型很少体现颗粒团聚过程，并采用平均粒径模拟团聚体尺寸，无法准确描述反应器内实际的传递和反应过程。为此，本研究提出一种新型灰熔聚流化床气化炉模型：(1) 气化炉分为鼓泡区和自由空域，鼓泡区由气泡相和乳化相组成，自由空域视为拟均相；(2) 考虑床内灰分团聚现象建立颗粒团聚机制，并结合颗粒初始粒径分布描述鼓泡区内灰分团聚过程。然后对所建立的模型进行求解并对比实际装置的运行数据与模型的模拟结果，两者偏差小于10%，说明模型的有效性。最后利用本模型计算不同氧气煤比的团聚体尺寸和碳转化率变化情况。进一步分析颗粒团聚对碳转化率的影响关系，团聚体处于临界尺寸时的碳转化率最大，若尺寸继续增加则颗粒无法维持流化状态。

Fluidized bed gasification technology has wide applications on coal industry due to its excellent mixing and heat transfer performances. With the influence of strong gas-solid mixing, char content of discharged ash will increase at high temperature. The operating temperature of traditional fluidized bed gasification is low to decrease the carbon loss, but it will lead to a shortage of gasification efficiency. As a result, the ash agglomerating fluidized bed gasification allowing limited particle agglomeration is proposed to increase operating temperature. The agglomeration size is the core of ash agglomerating gasifier so it is important to investigate the process of ash agglomeration. Expensive costs will be required if the research of complicated particle behavior in the gasifier depends on experimental analysis only. Thus, it is necessary to combine reactor modeling with experiment to improve research efficiency. However, the actual reaction and transport process of ash agglomerating gasifier cannot be described by existing models because the particle agglomeration was neglected and particle size was average during the modeling process. In this paper, a novel model for ash agglomerating fluidized bed gasifier was proposed: (1) the gasifier is divided into bubbling region consisting of bubble and emulsion phases, and freeboard regarded as pseudo-homogeneous phase; (2) the particle agglomeration is described by the integration agglomeration mechanism considering the particle agglomerating phenomenon, and the initial size distribution of particle. The model was validated according to the comparison that the deviation of simulation results and practical data is within 10%. Finally, the agglomeration size and carbon conversion with different oxygen-coal ratio was calculated by the model. With the agglomeration size reaching the critical value, the maximum carbon conversion is observed. The fluidization of agglomeration cannot keep if the agglomeration size exceeds the critical value.