污泥及其与煤混合物的热解特性和灰熔融特性

采用热重分析法对造纸污泥、市政污泥及其与煤的混合物的热解特性进行了系统研究.揭示了污泥、煤及其两者混合物热解特性的异同,研究了升温速率、掺混比等因素对混合试样热解特性的影响,提出了挥发分综合释放特性指数.研究表明:造纸污泥的挥发分析出特性与烟煤相当,而市政污泥的挥发分析出特性远优于造纸污泥和烟煤;在污泥与煤混合物的热解过程中,2种组分之间的相互作用可以忽略不计.随着升温速率的增加,污泥与煤混合物的挥发分初析温度提高,挥发分最高析出速率和平均析出速率升高.但升温速率对挥发分析出总量没有明显影响.测定了煤灰和污泥灰在不同混合比例下的熔融特征温度,测试结果表明,随着污泥灰比例的增大,混合试样的灰熔点逐渐下降,但由于存在低温共熔现象,不按线性规律变化.

Pyrolysis characteristics and ash fusion property of sludge and blended fuel of sludge and coal

Pyrolysis characteristics of paper mill sludge,municipal sewage sludge,one kind of coal and the mixtures of sludge and the coal were investigated with a thermogravimetric analysis apparatus.The difference of pyrolysis behavior of paper mill sludge,municipal sewage sludge,coal and sludge-coal blends were disclosed,and the influences of heating rate and mixing ratio of sludge and coal on the pyrolysis process were studied.A comprehensive devolatilization parameter was put forward.It is found that the pyrolysis feature of paper mill sludge is similar to that of the bituminous coal,and that of the municipal sewage sludge is much better than that of the paper mill sludge and bituminous coal.The pyrolysis behavior of sludge-coal blends follows the behavior of their parent materials in an additive manner,the two fuels do not chemically interact on each other under inertial conditions indicating a general lack of synergistic effects.With the increase of in heating rate,the initial pyrolysis temperature of sludge-coal blends increases,also the maximum release rate and average release rate of volatile increase rapidly.However,the heating rate has no notable influence upon the total amount of volatile released.The ash fusion temperature of sludge ash,coal ash and their blends were measured.Test results show that the low temperature co-fusion of blended ash leads to the nonlinear relation between fusion temperature and ash mixing ratio,and the ash fusion temperature decreases with the increase in content of sludge ash in blended ash.