添加剂对煤粉-污泥混合燃烧特性的影响及动力学

Effects of different additives on co-combustion of pulverized coal-sludge and kinetic analysis

采用热重分析法考察污泥、煤粉以及两者混合样品的燃烧特性,通过着火温度(Ti)、燃尽温度(Tb)以及综合燃烧特性指数(S)的变化,进一步研究添加剂对污泥-煤粉混合燃烧特性的影响,并探讨催化燃烧机理。结果表明:添加污泥能够降低煤粉的Ti,加速煤粉热解燃烧,改善煤粉的燃烧性能;但当污泥掺混比>10%时,混合样品的最大失重速率降低,Tb升高,综合燃烧性能S变差。CaO,Na_2CO_3能够促进挥发分析出燃烧,并带动后续固定碳的燃烧,因此混合样品的燃烧速率提高,燃烧时间缩短,综合燃烧性能改善;MnO_2,Fe_2O_3对混合样品的无明显催化作用,且降低了混合样品的最大燃烧速率。同时,动力学分析表明添加CaO,Na_2CO_3能够减小燃烧体系的活化能,而添加MnO_2和Fe_2O_3对混合样品的表观活化能无明显影响。

Some experiments were conducted in a thermogravimetric analyzer to investigate the thermal behaviors of sludge,pulverized coal and their blended fuels. By analyzing the change of ignition temperature（ Ti）,burnout temperature（ Tb） and comprehensive combustibility index（ S）,the effects of different additives on the co-combustion of sludge- pulverized coal were studied and the mechanism of catalytic combustion was discussed. Results indicate that adding sludge can decrease the Tiof pulverized coal and accelerate its pyrolysis and combustion which improves the combustion performance of pulverized coal. However,when the mixing ratio of sludge is more than 10%,the maximum weight loss rate of blended samples decreases significantly and Tbincreases. The comprehensive combustion performance for blended fuels is deteriorated. Calcium oxide and sodium carbonate contribute to the devolatilization and combustion of volatile matter,thereby drive the subsequent combustion of fixed carbon. Therefore,the two additives improve the burning rate and comprehensive combustion performance of blended fuels,and shorten the burning time.Manganese dioxide and iron oxide have no significant catalysis on blended fuels and reduce its maximum combustion rate. Meanwhile,the kinetic analysis shows that adding calcium oxide and sodium carbonate can reduce the apparent activation energy of combustion system,while adding manganese dioxide and iron oxide have no obvious effect on that of blended fuels.