【作者】 陈雷；

【导师】 代建军； 吴锋清；

【作者基本信息】 北京化工大学 ， 材料与化工（专业学位）， 2023， 硕士

【摘要】 化石能源的大量使用带来了环境问题、气候变化、能源危机,生物质能作为可再生能源的主力,对于我国碳中和目标的实现具有重要意义。本实验使用热解气化循环流化双床,试验设备高约5.7 m,宽3 m,实验进料速率选择50 kg/h,利用该装置对榉木颗粒（Beech wood particle,BP）在不同热解与气化温度下的性质变化进行了探究。（1）对设备运行参数进行计算,得出床料快速流态化气速11.8 m/s,选定气化炉工作气量为75 Nm³/h,对应颗粒循环速率G_s约为89.31 kg/（m²·s）。一步法与两步法实验中,两者循环阶段压力均处于5～12 k Pa,一步法反应时间更短,更适于工业上连续化生产。分析实验过程中非机械阀门前后压力变化从升温阶段到循环阶段,气化炉与热解炉平均压力差从0.011 k Pa增加至1.83 k Pa,根据非机械式阀门与两反应器间压力差变化判断,循环过程中通过床料实现了气化炉与热解炉相对隔离。（2）榉木颗粒利用热重分析（Thermogravimetric analysis,TG）将热解过程为三个阶段,第二阶段（160～510℃）为失重的主要阶段,质量损失为62.81 wt.%,主要为纤维素的脱羟基、脱羧、脱羰基和脱甲氧基等复杂反应。随着热解温度升高,生物炭产率逐渐降低,生物炭中sp²杂化的碳原子逐渐向sp³杂化与缺陷炭转化,促进生物炭中的脱羧反应,同时无定形碳结构含量增加。一步法与两步法相比,两种生物炭化学结合态变化不大。（3）榉木生物油（Beech particle bio-oil,BPO）在热解炉温度550℃、气化炉800℃时产率最高,达到32.88%,苯酚、苯衍生物为生物油中的主要成分,主要来自木质素中愈创木基（guaiacyl,G单元）、对-羟基苯基（p-hydroxy phenyl,H单元）、紫丁香基（syringyl,S单元）的裂解断链脱氧、脱甲基。不可凝气体主要为CO₂、CO、CH₄、H₂,双床循环时氧气、水蒸气促进了水煤气反应及C的气化。（4）对实验进行能量分析,能量产率达到56.52%～82.68%,其中生物油能量产率达到18.64%～52.45%,生物炭次之,产率为22.13%～33.62%,热解气最少,介于1.46%～15.75%;对生物炭进行亚甲基蓝与碘吸附实验,两步法中气化炉温度800℃时,热解温度从450℃升高至600℃时,亚甲基蓝吸附值从184.04 mg/g增加至261.38 mg/g,碘吸附值从80.28 mg/g增加至99.72 mg/g,一步法中由于循环时间的延长,亚甲基蓝与碘吸附值进一步提高至327.24 mg/g与117.46 mg/g。更多还原

【Abstract】 The extensive use of fossil energy has brought about environmental problems,climate change,and energy crisis,and biomass energy,as a mainstay of renewable energy,is of great significance for the achievement of carbon neutrality goal in China.In this experiment,a 50 kg/h pyrolysis and gasification circulating fluidized dual bed with a height of about 5.7 m and a width of 3 m was used to investigate the pyrolysis and gasification behavior of beech wood particle（BP）at different pyrolysis and gasification temperatures.（1）The rapid fluidization gas velocity of the bed material in the device was calculated,and the working gas volume of the gasifier was selected as 75Nm³/h,which corresponds to a particle circulation rate Gs of about 89.31kg/（m²·s）.The pressure in the cycling stage of both one-step and two-step experiments was in the range of 5～12 k Pa,and the average pressure difference between the gasifier and pyrolyzer increased from 0.011 k Pa in the no-load stage to 1.83 k Pa in the cycling stage during the experiment,and the temperature of the pyrolyzer increased rapidly,which realized the dynamic relative isolation between the gasifier and the pyrolyzer,and the reaction time of the one-step method was shorter and operationally more suitable for subsequent industrialization..（2）The beech wood particle were pyrolyzed into three stages by Thermogravimetric analysis.Stage 2（160～510°C）was the main stage with62.81 wt.%weight loss,when the complex reactions such as dehydroxylation,decarboxylation,decarbonylation and demethoxylation of cellulose were mainly carried out.As the pyrolysis temperature increases,the sp²hybridized carbon atoms in biochar gradually transformed to sp³hybridized and defective carbon,and the C-O changes had little relationship with the changes of pyrolysis and gasification temperature,which was favorable to promote the decarboxylation reaction in biochar,while the content of amorphous carbon structure increased.The one-step method showed little change in the chemical binding state of the two biochars compared to the two-step method（3）Beech particle bio-oil had the highest yield of 32.88%at the pyrolyzer temperature of 550°C and the gasifier of 800°C.Phenols and benzene derivatives were the main components in bio-oil,which were produced from the cracking of broken chains of guaiacyl,p-hydroxy phenyl and syringyl in lignin to deoxygenate and demethylate.The non-condensable gases are mainly CO₂,CO,CH₄and H₂.Oxygen and water vapor can promote the water gas reaction as well as methane formation and the oxidation of gasification of char.（4）The energy analysis of the whole equipment showed that the energy yield reached 56.52%～82.68%,among which the highest energy yield of bio-oil reached 18.64%～52.45%,followed by biochar with 22.13%～33.62%and the least pyrolysis gas between 1.46%～15.75%and methylene blue and iodine adsorption experiments were also conducted on the produced biochar.The adsorption values of methylene blue increased from 184.04 mg/g to 261.38mg/g and iodine adsorption values increased from 80.28 mg/g to 99.72 mg/g when the pyrolysis temperature was increased from 450°C to 600°C at a gasifier temperature of 800°C.In the one-step method,the adsorption values of methylene blue and iodine further increased to 327.24 mg/g and 117.46mg/g due to the extension of the cycle time.更多还原