文档介绍：摘要 I 摘要对富氧燃烧下循环流化床锅炉炉内的传热特性进行了研究分析。参考常规空气状态下的传热模型,建立循环流化床锅炉在富氧燃烧下的传热模型。在不同氧气浓度( 如 30% , 50% , 70% 氧气浓度) 下,分析了烟气成分、颗粒粒径、烟气温度、空隙率、烟气浓度、炉膛高度等参数对锅炉内部气固两相的流动、挥发份的释放和燃烧、焦炭燃烧的影响,得到各参数对富氧条件下的循环流化床传热参数影响曲线。燃烧模型结合了等密度缩核模型和等径缩核模型,引入了和煤种相关的灰层阻力扩散速率,动力反应速率引入了通用煤种理论。通过和常规空气下的传热计算结果相比,验证模型的准确性。主要结论为:富氧条件下相比空气模式,烟气成分对传热系数的有影响但不大,传热特性变化不是太明显,常规锅炉有可能通过一些较简单的改造来满足富氧燃烧的条件。选择了一个 300MW 循环流化床锅炉机组为算例来研究锅炉内部传热特性,通过模型的分析结果,探讨富氧燃烧下的循环流化床锅炉设计。分别对 30% , 50% , 70% 三个浓度下炉膛的受热面面积比以及吸收热量比等进行计算,对比得到富氧燃烧下的炉型。归纳出 CFB 锅炉尺寸、流动以及传热特性随着氧气浓度的增加的变化规律并进行了富氧燃烧下的炉型概念性设计。关键词:循环流化床;富氧燃烧;传热;模型华北电力大学硕士学位论文 II Abstract Making an analysis and research to the heat transfer charac ter of circulating fluidized bed under oxy-enriched atmosphere. Under different oxygen concentration(such as 30%, 50%, 70% oxygen concentration), st udied impact parameters such as gas composition, particle diameter, flue gas temp erature, voidage matter, gas concentration, furnace height etc. how to effect the gas-so lid phase flowing in boiler, diffusion and combustion of volatile and bustion, and get the effect curve of CFB heat transfer under oxy-enriched condition. Th ereinto bustion bined ic shrinkage nuclear model and the isodiametric shrinkage nuclear model, brought in the ash layer resistance diffusion ra tes which is relevant to coal category, and dynamic reaction rate brought in general lithot ype theory. paring with the results of normal air condition, proving the veracity. Get the main conclusions: in the oxy-enriched pared to norma l air condition, the co efficient of heat transfer can be influenced by positi on but not very much, the change of heat transfer characteristics is not a lot, it is feasible to transform the normal boilers into oxy-enriched ones by some easy remaking. Ch oose an example of 300MW circulating fluidized bed unit to discuss boiler inner heat transfer ch aracter, and designed the CFB boiler under oxy-enriched atmosphere according to the results. Calculated the heating area ratio and