基于简单碰撞理论煤粉燃烧动力学模型的研究—PART Ⅱ:颗粒表面的氧气浓度分布模型  

STUDY ON THE REACTION KINETICS MODEL OF PULVERIZED COAL COMBUSTION BASED ON SCT -PART II: OXYGEN CONCENTRATION DISTRIBUTION ON PARTICLE SURFACE

作　　者：傅培舫[1] 方庆艳[1] 周怀春[1] 

机构地区：[1]华中科技大学煤燃烧国家重点实验室,武汉430074

出　　处：《工程热物理学报》2005年第4期701-704,共4页Journal of Engineering Thermophysics

基　　金：国家自然科学基金资助项目(No.50476070)

摘　　要：为了较准确地预报炉内煤粉燃烧速率,正确区分TGA中滞止煤粉表面与炉内载流煤粉表面氧气浓度的变化规律是非常关键的。从TGA中非稳态条件下坩埚内颗粒表面氧气浓度分布的数理解知,煤样的氧化过程是同时进行的,只是上部的氧化速率大一些,底部的氧化速率小一些;同一样品,同一升温速率,试样的堆积厚度的差异,会影响实验结果的重复性。分析表明,在初始和反应结束时,坩埚内颗粒表面氧气浓度等于环境浓度;反应速率达到最大值时,颗粒表面氧气浓度达到最小值。颗粒在炉内流动燃烧过程中,环境中氧气浓度值是单调减少的,煤焦表面氧的浓度是非线性变化的。It is very pivotal for more accurately predicting the pulverized coal (p.c.) burning rate to differentiate the changes of oxygen concentration on p.c. surface under the condition of still p.c. in TGA and entrained p.c. in furnace. According to the solution of unstable oxygen mass transfer equation with source item of reaction, the oxidation of p.c. particles in crucible take place at the same time, but the oxidation rate is more quick at the top than at the bottom. For the same coal sample at the same heating up rate, the height of packed p.c. sample would affect TGA results. It is shown that the oxygen concentration of p.c. surface is up to the minimum value while the burning rate is up to the maximum value, and at the start and end of combustion, the oxygen concentration is equal to the value of ambient. In the process of entrained p.c. combustion in furnace, the ambient oxygen concentration is decreased monotonously and the change of oxygen concentration of p.c. surface is nonlinear.

关 键 词：煤粉燃烧 非稳态传质 浓度分布 TGA 

分 类 号：TK16[动力工程及工程热物理—热能工程]