煤的超临界水热氧化反应动力学及系统热能的研究

Studies on Reaction Kinetics of Coal's Thermal Oxidation in Supercritical Water and Thermal Energy of the System

在连续式反应器上研究了煤的超临界水氧化反应，考察了反应时间、压力、温度和过氧量对试验效果的影响，并应用热量平衡规律对反应过程产生的热能进行了分析．结果表明：反应温度、停留时间和过氧量是影响超临界水氧化反应的重要因素，氧化反应的程度随着温度的升高及时间和过氧量的增加而加剧；氧化反应对水煤浆浓度的反应级数为1．79，对氧的反应级数为0．28，反应活化能和频率因子分别为（112.3±5．6）×10^3kJ·mol^-1和（4．12±0．35）×10^2，所建立的反应动力学模型与试验结果的偏差在±9％之内；在试验条件下，系统的热效率可达80％以上；在反应的初始阶段（30～75s），不完全燃烧热损是系统的主要热损；在反应终了的阶段（75～120s），“排烟”热损是系统的主要热损．

Supercritical water oxidation （SCWO） of coal was studied on a continuous reactor. The influence of reaction time, pressure, temperature and excess of oxidant on experimental result was investigated, and the thermal energy produced during the reaction was analyzed by use of heat balance law. Results show that reaction temperature, residence time and excess of oxidant are the notable factors that effect the reaction of supercritical water oxidation. The degree of the oxidation intensifies with increasing the temperature, time and excess of oxidant. The oxidation reaction is in the order of 1.79 in terms of concentration of coal slurry and 0.28 in terms of oxidant, and the activation energy and frequency factor are （112.3±5.6） kJ·mol^-1 and （4.12±0.35） ×10^3 respectively. The deviation between the results of the reaction kinetics model and the experimental data is within ±9 %. The thermal efficiency of the system can reach 80 % under the experimental conditions. In the initial stage of the reaction （30-75 s）, the heat loss due to incomplete combustion is the main heat loss, while in the final stage of the reaction （75-120 s）, the flue gas heat loss becomes the main heat loss of the system.