煤焦表面加压多组分扩散控制反应机制的研究

在湿空气和富氧条件下,燃煤电站锅炉、工业炉和高压煤气化炉中，煤焦高温燃烧气化，不同于化学动力学阶段，固相反应以CO生成为主的多组分反应，化学动力学过程耦合了较强的扩散控制过程，动力学模型和颗粒边界层的速度场、温度场和浓度场信息一直是研究的难点。采用不同煤阶的煤焦颗粒，在冻结和非冻结气相反应条件下，压力0.1-4MPa，终温 1800K，不同浓度比的O2、CO2和H2O混合气，以载流煤粉颗粒相对速度流过二维煤焦圆柱棒或平板，研究煤焦表面边界层、CO/CO2比、附着和离析火焰的生成规律，反应速率突跃条件及主要特征参数（反应速率、反应时间和转化率）的预测模型。借助数值实验和物理试验相结合的方法，获得单因素和多因素的作用机制，以检验预测模型的正确性。揭示高温高压多组分流动条件下煤焦燃烧气化的耦合规律及转变温度；建立对应条件下的特征参数计算模型；为煤的燃烧气化设计、预测与控制奠定理

For coal char conversion at high temperature in humid air-flow and oxy-fuel in coal-fired boiler power generation，industrial furnace,and coal gasifier,CO is substantially produced on char surface by multicomponent heterogeneous reactions and is controlled by diffusion, which distinguishes from the regime of chemical kinetics. It is the key factors of influence on the accurate prediction that chemical kinetics models are coupled with velocity field, temperature field and concentration field in the process of coal char conversion. Char particles formed from different coal rank, under conditions of P=0.1-4MPa，T≤1800K, mixtures which consist of different concentration of O2,CO2 and H2O flow in 2D direction around cylinder char-rod or char flat plate at relative velocity of pulverized coal in entrained flow, the boundary layers of velocity field, temperature field and concentration field, ratio CO/CO2， attached and detached flame, the condition of which reaction rate changes abruptly and prediction model of characteristic parameters such as reaction rate, burn-off time and burn-off extent is studied. With the aid of computational simulation and experiment, variable is separated from complex factors and the effect of every factor and models are verified .The objects are to discover the law of interaction between combustion and gasification at high pressure and high temperature in multicomponent system, and set up the prediction model of characteristic parameters and improve the precision of prediction so as to design and control of coal char conversion process.