An isothermal model is commonly used in computational fluid dynamics (CFD) modeling of biomass devolatilization in fluidized beds. However, the particle internal heat transfer, which is neglected by the isothermal model, influences significantly the devolatilization process for large biomass particles. To consider the effect of internal heat transfer, a heat-transfer-corrected isothermal model is introduced by comparing the differences between an isothermal model and a nonisothermal model. Two correction coefficients for external heat transfer, H_T, and reaction rate, H_R,i, were defined to correct the conventional isothermal model. The predictions of the heat-transfer-corrected isothermal model and the nonisothermal model were in good agreement with the experimental data for both thermally thick (Biot number, Bi ≥ 1.0) and thermally thin (Bi < 1.0) biomass particles, while the conventional isothermal model gave reasonable results only for thermally thin biomass particles. The heat-transfer-corrected isothermal model was further implemented in a CFD model to simulate biomass devolatilization in a batch bubbling fluidized bed. Compared to the conventional isothermal model, the heat-transfer-corrected isothermal model had similar computational efficiency, but it predicted a lower heating rate and a lower devolatilization rate, which were in good agreement with the observations from single-particle modeling.

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热厚生物质颗粒脱挥发分的传热校正等温模型

等温模型通常用于流化床中生物质挥发的计算流体动力学（CFD）建模。然而，等温模型所忽略的颗粒内部传热会极大地影响大型生物质颗粒的脱挥发分过程。为了考虑内部传热的影响，通过比较等温模型和非等温模型之间的差异，引入了经过传热校正的等温模型。外部传热的两个校正系数H _T和反应速率H _R，i被定义为校正常规的等温模型。传热校正的等温模型和非等温模型的预测与热厚（比奥数，Bi≥1.0）和热薄（Bi的实验数据）吻合良好。<1.0）的生物质颗粒，而常规的等温模型仅对热薄的生物质颗粒给出了合理的结果。在CFD模型中进一步实施了传热校正的等温模型，以模拟分批鼓泡流化床中的生物质脱挥发分。与传统的等温模型相比，传热校正的等温模型具有相似的计算效率，但是它预测了较低的加热速率和较低的脱挥发分速率，与单颗粒模型的观测结果非常吻合。