超细干污泥与煤粉的着火特性分析

Thermal Analysis on Ignition Characteristics of Micro-pulverized Sewage Sludge With Coal

利用热天平研究沈阳市3个污水处理厂超细化干污泥与超细煤粉的着火特性,讨论了氧气浓度、污泥掺混比例对污泥着火特性的影响,并对燃烧反应低温段进行了反应动力学分析。结果表明,当升温速率为20℃/min,氧气体积浓度为20%时,污泥样品的着火温度低于铁法煤粉约50～60℃,主要原因是污泥挥发分含量(49.3%)远高于煤粉(30.3%);挥发分含量(x)和着火温度(y)呈指数关系y=215.0433+2382.723e-x/12.1355;厌氧消化污泥与生物膜法腐殖污泥具有相近的挥发分含量及着火温度,由于二者的挥发分含量低于活性污泥法的剩余污泥,二者的着火温度相对较高;随着氧气浓度和挥发分含量的增加,超细化干污泥和煤粉的着火温度降低,但挥发分含量对着火温度的影响远大于氧气浓度的影响。污泥掺混比例大于40%时,污泥与煤掺混样品的着火温度明显下降。

The ignition characteristics of sewage sludges which were obtained from three municipal wastewater treatment plants（WWTP） in Shenyang City, were studied with thermogravimetric apparatus. The effect of oxygen concentration and sludge/coal ratio on the ignition characteristics and the reaction kinetics in the low temperature range were analyzed. The results show that the ignition temperatures（ti） of sludge is about 50-60℃ lower than Tiefa coal. The main reason is that sludge has more volatile matter w（Va）（49.3%） than coal （30.3%）. The regression equation of ignition temperature （y） and volatile content （x） may be expressed as： y=215.043 3＋2 382.723e^-x/12.1355. The digested sludge in an activated sludge process and excess sludge in an BAF process has similar w（Vd） and ti. Their W（Vd） is clower and their ti is high than excess sludge in an activated sludge process. The ti decreased with increasing concentration of oxygen and W（Vd） for a given sludge source and sludge/coal ratio, but the effect of w（Vd） on the ti is greater than concentration of oxygen. When the mixing ratio of sludge is more than 40%, ti of samples is decreased significantly.