高灰低挥发分煤空气分级燃烧特性研究

Study on Air-staged Combustion of High-Ash and Low-Volatile Coal

为降低高灰低挥发分煤在燃烧过程中产生的NOx,在研究化学渗透脱挥发分热解模型的基础上,利用气相燃烧的简化机理对计算流体动力学软件模拟煤粉燃烧过程进行改进,并进行空气分级燃烧工况的数值模拟,着重分析高灰低挥发分煤空气分级燃烧的控制机制。通过与未分级燃烧进行比较,发现高灰低挥发分煤采用空气分级燃烧,可以形成还原性气氛来抑制NOx生成,但存在煤粉着火滞后和NOx排放量较高等问题。

In order to reduce the NOxproduced in the combustion of high-ash and low-volatile coal,the simplified mechanism for gas-phase combustion was used to improve Computational Fluid Dynamics simulation on the combustion process of pulverized coal and the numerical simulation of air-staged combustion conditions were carried out on the basis of the study of Chemical Percolation Devolatilization.Then the paper analyzed the control mechanism of airstaged combustion,and found that air-staged combustion was adotped for high-ash and lowvolatile coal to form a reducing atmosphere and suppress the generation of NOx,but there were existing problems such as pulverized coal ignition delay and higher NOxemission,etc.