摘要
气流床煤气化炉内的湍流流动和反应过程存在强烈耦合作用,为确定气化炉不同区域中起主导作用的控制因素,通过对Texaco气化炉进行三维数值模拟以及对计算结果进行分析,详细列出了气化炉中与流动、反应相关的主要长度尺度和时间尺度.通过对这些特征尺度进行比较,发现在火焰区不能忽略因气体组分脉动而对焦炭异相反应产生的影响;在非火焰区,尽管慢反应控制气相反应过程,但总体来说,同相反应的时间尺度远小于宏观混合过程的时间尺度,这说明采用快反应假定对气化炉内的化学机理进行简化能够合理预测气化炉的运行特性.
In an entrained flow coal gasifier, strong coupling exists between turbulent flow and reaction. In order to figure out which factor in the mixing process, homogeneous reaction and heterogeneous reaction, dominates the coal gasification process in a Texaco gasifier, numerical simulations for a Texaco gasifier were carried out. Based on simulation results, time scales and length scales of turbulent flow and reactions in different regions of the gasifier were compared. The analysis shows that the interaction between species fluctuation and particle heterogeneous reactions is very important in the flame region and can＇ t be neglected. In the non-flame region in the gasifier, slow reverse homogeneous reactions dominates gasification reactions. However, time scales of homogeneous reactions are much smaller than those of macro-mixing process. This means that the assumption that mixing process dominates gasification process in this region is reasonable and can be used in numerical modeling to predict the performance of an entrained coal gasifier.
出处
《燃烧科学与技术》
EI
CAS
CSCD
北大核心
2009年第4期287-292,共6页
Journal of Combustion Science and Technology
基金
国家重点基础研究发展计划(973)资助项目(2004CB217705)
关键词
气流床煤气化炉
数值模拟
时间尺度
长度尺度
entrained flow coal gasifier
numerical simulation
time scale
length scale
