Bifurcation characteristics of coal spontaneous combustion and analysis of critical state of gaseous reaction in a packed bed

• 来源期刊: 煤炭学报（英文版）
• 年，卷（期）: 2008,（2）
• 页码范围: 244-247
• 页数: 4页
• 语种: 英文

摘要

The numerical model was presented for the coal combustion in the packed bed.The bifurcation characteristic of the ignition-extinction of solid-phase smoldering and transition to flaming was studied for the packed bed of coal. One of the Frank-Kamenetskii parameter β1 was selected as the control parameter. The computed results show that the bifurcation curve is obviously divided into two zones of solid-phase reaction and gasphase reaction, and the total process of ignition-extinction presents twice bifurcation characteristic. Moreover, the vanishing of critical state of ignition-extinction is studied. One of the transition points, ε2=0.05, is numerically solved for the vanishing of critical state. The larger the value of ε2 is, the easier the gas-phase can react. However, the combustion temperature will decrease with increasing ε2. The other transition point α2=0.53 is also obtained. With increasing the value of α2, the combustion temperature of gas-phase reaction is close to the smoldering temperature of coal. When α2 is infinite, the only reaction occurring is the smoldering combustion of solid-phase, and the gas-phase cannot react.