原料对自由落下床中生物质与煤共热解行为的影响

摘要

在500～700℃和生物质混合比0～100％(质量分数)条件下,利用自由落下床反应器考察原料对生物质与煤共热解行为的影响.所用煤原料为大雁褐煤(DY)和铁法烟煤(TF),而生物质原料为农业废弃物秸秆(LS)和木材加工余料白松木屑(SD).结果表明,即使在自由落下床中停留时间短的条件下,生物质与煤共热解的协同效应仍然发生.原料种类对共热解产品的产率和半焦反应性影响大:以综纤维素和灰分含量大的LS为原料时,共热解的协同效应比以SD为原料时明显；以高阶煤TF为原料时,共热解的液体产率高于以低阶煤DY为原料时的产率；在特定条件下共热解可提高半焦的反应性；与TF相比,DY存在下的共热解有利于提高半焦的反应性.在生物质与煤共热解过程中,通过选择适当原料可以制取目标产品.%Effects of feedstock on the co-pyrolysis of biomass and coal were investigated in a free fall reactor at 500°C～700°Cwith biomass blending ratio of 0 ～100％(mass ratio).The selected coal samples were Dayan brown coal (DY) and Tiefa bituminous coal(TF),and the biomass samples were agricultural residues legume straw (LS) and woody residues pine sawdust (SD).The results indicate that the synergy can occur even in a short gas residence time during the co-pyrolysis of biomass and coal in a free-fall reactor.The product yields and the CO2 reactivity of char from the co-pyrolysis are greatly influenced by the type of feedstock.The synergy in the presence of LS with high holocellulose and ash content is more significant than that in the presence of SD.The liquid yield of high rank TF co-pyrolysis is higher than that of low rank DY coal.The char reactivity can be improved by the co-pyrolysis at specific conditions.The co-pyrolysis in presence of DY can improve the reactivity of the produced char.