An experimental study on the ignition of single coal particles at low oxygen concentrations (\({X_{{{\rm{O}}_2}}} < 21\% \)) was conducted using a tube furnace. The surface temperature (T_s) and the center temperature (T_c) of the coal particles were obtained from the images taken by an infrared camera and thermocouples respectively. The ignition processes were recorded by a high-speed camera at different \({X_{{{\rm{O}}_2}}}\) values and furnace temperatures T_w. Compared with literature experimental data obtained at a high \({X_{{{\rm{O}}_2}}}\) value, the ignition delay time τ_i decreases more rapidly as \({X_{{{\rm{O}}_2}}}\) increases at the low \({X_{{{\rm{O}}_2}}}\) region. The responses of T_s and T_c to the variation of \({X_{{{\rm{O}}_2}}}\) are different: T_s decreases while T_c remains nearly constant with increasing \({X_{{{\rm{O}}_2}}}\) at a low \({X_{{{\rm{O}}_2}}}\) value. In addition, τ_i is less sensitive to T_w while the ignition temperature T_i is more sensitive to T_w at a low \({X_{{{\rm{O}}_2}}}\) value than in air. Observations of the position of flame front evolution illustrate that the ignition of a coal particle may change from a homogeneous mode to a heterogeneous or combined ignition mode as \({X_{{{\rm{O}}_2}}}\) decreases. At a low \({X_{{{\rm{O}}_2}}}\) value, buoyancy plays a more significant role in sweeping away the released volatiles during the ignition process.

使用管式炉进行了在低氧浓度（\（{X _ {{{rm {O}} _ 2}}} <21 \％\））点燃单个煤颗粒的实验研究。煤颗粒的表面温度（T _s）和中心温度（T _c）分别由红外相机和热电偶拍摄的图像获得。点火过程由高速摄像机以不同的\（{X _ {{{\ rm {O}} _ 2}}} \）值和炉温T _w记录。以高得文献的实验数据进行比较\（{X _ {{{\ RM {ö}} _ 2}}} \）值，点火延迟时间τ_我更迅速减小作为\（{X _ {{{rm {O}} _ 2}}} \）在较低的\（{X _ {{{rm {O}} _ 2}}} \）区域增加。T _s和T _c对\（{X _ {{{rm {O}} _ 2}}} \\）变化的响应是不同的：T _s减小，而T _c随着\（{X_ { {{\ rm {O}} _ 2}}} \）的\（{X _ {{{\ rm {O}} _ 2}}} \\）低值。此外，τ_我是较不敏感的Ť_瓦特，而点火温度Ť_我是更敏感Ť_瓦特在低\（{X _ {{{\ rm {O}} _ 2}}} \）的值比空气中的值大。对火焰前沿演变位置的观察表明，随着\（{X _ {{{{\ rm {O}} _ 2}}} \\）减小，煤粒的着火可能从均质模式变为异质或组合点火模式。。在\（{X _ {{{rm {O}} _ 2}}} \\较低的情况下，浮力在点燃过程中清除挥发物起着更重要的作用。