【作者】 王新运；

【导师】 陈明强； 王君；

【作者基本信息】 安徽理工大学 ， 化学工艺， 2006， 硕士

【摘要】 生物质能是重要的可再生资源之一,而热解是未来最有前景的生物质利用方式之一。通过对生物质的热解动力学研究,可以获得热解反应动力学参数,对于判断热解反应机理和影响因素以及优化反应条件具有重要意义。 利用热分析仪,在氮气气氛下,采用不同升温速率和催化剂对三种生物质（马尾松、棉秆和杉木）热解行为进行了研究。实验考察了升温速率、生物质组成和催化剂对三种生物质热解行为的影响,研究表明:随着升温速率的增加,TG和DTG曲线均向高温侧移动;灰分越高,热解温度和达到最大热解速率对应的温度越低,挥发分越高,最大热解速率越高;NaOH、Na₂CO₃、Na₂SiO₃和NaCl使初始热解温度和最大失重速率对应的温度向低温区移动。TiO₂和HZSM-5对马尾松和杉木的初始热解温度和最大失重速率没有明显影响,却提高了棉秆的初始热解温度和最大失重速率对应的温度;碱性催化剂NaOH、Na₂CO₃和Na₂SiO₃可以明显降低最大失重速率,NaCl和HZSM-5趋向提高最大失重速率,TiO₂对最大失重速率几乎没有影响;NaOH、Na₂CO₃碱性催化剂可增大热解的放热峰,而TiO₂和HZSM-5对热解的反应热影响很小。 根据热重实验数据,采用Flynn-Wall-Ozawa法求出了生物质热解反应的活化能。利用双外推法计算表明:未处理试样在主要挥发分脱除阶段的最佳机理函数是Z-L-T方程(F（α）={[1/（1-α）]^1/3-1}²),热解过程受三维扩散控制。而该法不能确定催化热解的机理函数。通过Popescu法计算表明:对于未处理的试样,在250℃～350℃区间内,Z-L-T方程是最佳机理函数,而在350℃-370℃区间内,Jander方程（F（α））=[1-（1-α）^1/3]²)是最佳机理函数。对于催化剂处理的试样,在250℃-290℃区间内,z-L-T方程是最佳机理函数。利用不同温度段的最佳机理函数求出了对应的动力学参数。比较发现,采用三种不同的方法,计算的活化能较为接近,推出的机理函数基本一致。 在氧气气氛下,采用不同升温速率对生物质裂解油的热解行为进行了研究。实验考察了不同气氛和升温速率对生物质裂解油燃烧特性的影响。根据热重实验数据,用Flynn-Wall-Ozawa法求出了生物质裂解油燃烧反应的活化能。用Popescu法确定了400℃～430℃内燃烧的最佳机理函数,发现二级化学反应更多还原

【Abstract】 Biomass energy is one of most important renewable energies. Pyrolysis is one of most promising methods of biomass utilization in future. Study on biomass pyrolysis kinetics which can obtain pyrolysis kinetic parameters is of great important significance toward judging pyrolysis mechanism and influence factors and optimizing reaction conditions.The thermal characteristics of three biomass samples, pine wood, cotton stalk and fir wood were investigated by thermal analysis technique at different heating rates in N₂ atmosphere. The influences of heating rate, biomass composition and catalysts on the process of biomass pyrolysis were researched. Experiments showed that TG and DTG curves all moved to higher temperature ranges with increasing heating rate. The higher ash content, the lower initial pyrolysis temperature and temperature at the maximum weight loss rates meanwhile the higher volatile content, the higher maximum weight loss rates. NaOH, Na₂CO₃, Na₂SiO₃ and NaCl made initial pyrolysis temperature and temperature at the maximum weight loss rates of three kinds of biomass shift to lower temperature regions, whereas TiC>2 and HZSM-5 made initial pyrolysis temperature and temperature at the maximum weight loss rates of cotton stalk move to higher temperature regions and had no obvious effects on initial pyrolysis temperature and temperature at the maximum weight loss rates of pine wood and fir wood. The basic catalysts NaOH, Na₂CO₃ and Na₂SiO₃ can obviously decrease the maximum weight loss rates while NaCl and HZSM-5 tend to increase the maximum weight loss rates, TiO₂ had few effects on the maximum weight loss rates. The basic catalysts NaOH and Na₂CO₃ can increase the pyrolysis exothermic peak while TiO₂ and HZSM-5 have minor effects on reaction heat.According to TG data, activation energies for pyrolysis of three samples were calculated by Flynn-Wall-Ozawa method. It was found that Zhuralev, Lesokin and Tempelmen （Z-L-T）equation(F（α）=1/（1-α）]^1/3-1}²) was the optimal mechanism function, which indicated that the thermolysis mechanism was three dimensional diffusion in pyrolysis temperature range for untreated samples by doubleextrapolation method, whereas double extrapolation method fail to apply for treated samples. It was found that Z-L-T equation was the optimal mechanism function in pyrolysis temperature range 250°C³50°C, Jander equation（F（a）=[l-（l-a）1/3]2） was the optimal mechanism function.which indicated that the thermolysis mechanism was three dimensional diffusion in pyrolysis temperature range 350oC³70oC for untreated sample and Z-L-T equation was the optimal mechanism function in pyrolysis temperature range 250°C²90°C for treated samples by Popescu method, and then, kinetic parameters of biomass pyrolysis was calculated by the optimal mechanism function of different temperature ranges . It was show that activation energy calculated and the optimal mechanism function obtained by three methods agree well with each other.The thermal characteristics of biomass pyrolysis oil were investigated by thermogravimetric analysis technique at different heating rates in O2 atmosphere. The influences of different atmosphere and heating rate on the pyrolysis or combustion process of biomass pyrolysis oil were researched. According to TG data, activation energy of the biomass pyrolysis oil was calculated by Flynn-Wall-Ozawa method. The optimal mechanism function of combustion in range 400°C⁴30°C was determined by Popescu method. It was found that second order（F（a）=（l-a）"1） , three order（F（a） =（l-a ）"2） and one and one-half order（F（a） =（l-a ）"1/2） of chemical reaction were fit for describing the combustion process at different temperature scopes, and then, the optimal function of different temperature range was used to calculate the kinetic parameters. Results indicated that the activation energy calculated by the two different methods are approximately the same.更多还原