Abstract:

The releasing characteristics of gas species during isothermal co-pyrolysis of pine sawdust (PS) and coal slime (CS) were studied in a micro fluidized bed reactor.Four main pyrolysis gaseous products,CH₄,CO,CO₂ and H₂,were investigated under different temperature and blending ratios.The kinetic parameters were calculated employing the universal integral method to examine the interaction of PS and CS during co-pyrolysis.It was observed by FT-IR that CS mainly contained aromatic compounds carrying C-O and C==O,while the PS was mainly consist of long-chain aliphatic hydrocarbon with-OH.The gas forming reaction rate of PS was higher than that of CS,and its value increased in a certain extent with the increase of biomass blending ratio.The kinetic parameters of pyrolysis gas formation of PS,CS and their blends were obtained by the mechanism function models,and the most probable mechanism function was determined by comparing the experimental and calculated values.The effect of blending PS and CS on the forming activations of the four gas species varied obviously.The activation energies of CO were significantly lower than the calculated ones,indicating that a positive synergistic effect existed between PS and CS.The co-pyrolysis reaction led to a negative effect on the formation of H₂ at a PS blending ratio of 75% as the activation energy was obviously higher than the calculated one.In comparison,biomass blending showed relatively small positive synergistic effect on the formation of CH₄,while that of CO₂ depended upon the blending ratio significantly.

Key words: micro fluidized bed reactor, biomass,coal slime, pyrolysis, isothermal reaction, reaction kinetics, interaction

摘要：

采用微型流化床反应器对松木屑和煤泥的等温混合热解气体释放行为进行实验研究。探讨不同温度和掺混比例对CH₄、CO、CO₂与H₂释放特性的影响，并通过模型配合法求解其动力学参数，研究松木屑和煤泥混合热解过程的相互作用。通过FT-IR检测发现煤泥的主要成分为含有C-O和C==O键的芳香化合物，松木屑则以带-OH键的长链脂肪烃为主。在等温稳定反应阶段，松木屑热解气体生成速率高于煤泥，随着生物质掺入比例的不断提高，混合原料气体生成反应速率亦呈现不同程度的增加。利用模型积分法求解了松木屑、煤泥及其混合物热解气体生成动力学参数，并通过实验值和计算值对比筛选出了最概然机理函数。通过活化能对比发现，混合热解对4种气体组分生成具有不同的影响作用，其中CO实验活化能明显低于计算值，表现为二者协同作用利于CO的生成释放；对H₂而言，在75%混合比例条件下，混合反应导致其生成活化能呈现协同负效应，使得活化能实验值明显高于计算值；相较而言，CH₄在混合热解过程影响相对较弱，并呈现小幅度的协同负效应，而CO₂的生成特性则受混合比例的影响较为明显。

关键词: 微型流化床, 生物质, 煤泥, 热解, 等温反应, 反应动力学, 相互作用