Abstract: At present, researchers generally believe that when Char-N transforms to NO, the Char-N reaction rate is directly proportional to the coke burning rate. This way of treatment ignores the difference of reaction area between coke and Char-N during the combustion of coke particles, which is quite different from the actual situation. As for this problem, based on a full consideration of the difference of reaction area between carbon base and Char-N caused by different forms of coke combustion, the combustion of coke particles was treated by a random pore model while the transformation of Char-N was treated by the contraction model. Finally, a comprehensive model with two models was established. The combustion process of coke particles with a particle size of 100 μm under O₂/CO atmosphere was simulated, and the conversion of Char-N to NO in the particles was also studied by programming and computing independently through Fortran. The results showed that the computational results of the new model agreed well with the experimental data and had good applicability. At the same time, the new model had the ability to characterize the parameters of Char-N transformation. The increase of the concentration of O₂ and the particle size of the coke will lead to the increase of the NO production in the reaction process. At the same time, because of the different changes of reaction area between coke and Char-N, the generation curve of NO was rising for the second times.

Key words: mass transfer, reaction kinetics, numerical simulation, Char-N

摘要： 目前，研究者普遍认为焦炭氮（Char-N）向NO转化时Char-N反应速率与焦炭燃烧速率成正比，这种处理方式忽略了焦炭颗粒燃烧过程中焦炭和Char-N反应面积变化的差别，与实际情况相差较大。针对此问题，本文充分考虑了焦炭燃烧时碳基和Char-N由于存在形式不同导致的反应面积变化的差别，在通过随机孔模型处理焦炭颗粒燃烧的同时采用收缩模型的思维处理Char-N的转化，建立了一个具有两种模型优势的综合模型。模拟了粒径为100μm的焦炭颗粒在O₂/CO₂气氛下的燃烧过程，以及颗粒内部Char-N向NO的转化过程。通过Fortran自主编程并进行计算。结果表明，新建立的模型计算结果能够与实验数据吻合，具有较好的适用性。同时新模型具有表征Char-N转化过程中各参数变化的能力。环境O₂浓度的增大和焦炭颗粒粒径的增大都会导致反应过程中NO生成量增多，同时由于焦炭和Char-N反应面积变化不同，NO的生成曲线存在二次升高的现象。

关键词: 传质, 反应动力学, 数值模拟, 焦炭氮