生物质与烟煤混燃过程灰分的烧结特性研究

Study on Sintering Characteristics of Ash From Combustion Process of Mixed Biomass and Bituminous Coal

生物质与煤的成分十分复杂,这些成分共同决定了生物质与煤混合热转化过程灰样的烧结或结渣特性,这对生物质与煤混合热转化技术的应用和推广具有重要影响。本文以典型的生物质秸秆和烟煤为原料,深入研究不同掺混比例以及灼烧温度和灼烧时间对生物质与煤混燃灰烧结特性的影响。研究结果表明:玉米秸秆与神木烟煤混燃过程中玉米秸秆的掺混比例越大,脱灰效应越明显。水稻秸秆与烟煤混燃后灰分含量要高于玉米秸秆与烟煤混燃后的灰分含量,这主要是由两种秸秆生物质的化学组分和结构不同所致。在相同的灼烧温度和掺混比例下,灼烧时间对灰分含量的影响不明显。随着灼烧温度的增加,玉米秸秆与烟煤混合热转化得到的灰样的灰分含量越低,脱灰效应越明显。当玉米秸秆的掺混比例由25%升至75%时,灰样形貌由原来的无规则形状或蜂窝状结构转变成明显的熔融粘结现象。灼烧温度升高,混燃灰样的结渣趋势增强,而灼烧时间对灰样微观形貌的影响较小。

The composition of biomass and coal is very complex,and these components jointly determine the sintering or slagging characteristics of ashes in the thermal conversion process of mixed biomass and coal,which has an important impact on the application and promotion of thermal conversion technology of the mixed biomass and coal.In this paper,typical biomass straw and bituminous coal were used as raw materials,and the influence of different mixing ratios,burning temperature and time on the sintering characteristics of the combustion ash of mixed biomass and coal was deeply studied.The results indicated that the higher the mixing ratio of corn stalk,the more obvious the deashing effect was.The ash content of rice straw mixed with bituminous coal was higher than that of corn straw mixed with bituminous coal,which was mainly caused by the different chemical compositions and structure of the two kinds of straw biomass.Under the same sintering temperature and biomass mixing ratio,the effect of sintering time on ash content was not obvious.With the increase of burning temperature,the lower the ash content of the mixed ash samples obtained from the thermal conversion of mixed corn straw and bituminous coal,the more obvious the ash removal effect.When the mixing proportion of corn straw increased from 25%to 75%,the ash morphology varied from irregular shape or honeycomb structure to obvious melting and bonding phenomenon.The slagging tendency of the mixed combustion ash was enhanced by the increase of the ignition temperature,while the effect of the burning time on the microstructure of the ash sample was small.