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类型 基础研究 预答辩日期 2017-11-29
开始(开题)日期 2015-12-22 论文结束日期 2017-10-18
地点 热能所一楼会议室 论文选题来源 973、863项目     论文字数 4 (万字)
题目 催化快速热解不同生物质原料生产芳烃和烯烃
主题词 生物质,沸石催化剂,流化床反应器,芳烃,烯烃
摘要 木质纤维素生物质可以转化为最初从化石基材料获得的生物燃料和化学品。尽管所有生物质类型都可以热和生物化学转化为生物燃料和化学品,但在各类型和组成之间,有效转化成烃的效率存在着显著差异。另化石消耗和环境问题也引发了对可再生能源的探索,如资源丰富且环境友好的生物质。催化快速热解是在单个反应器和步骤中将固体生物质转化成高价值化学品产品如芳烃和烯烃的先进的技术。在本文中,首先描述了研究中使用的各种生物质材料。其次,在流化床反应器中进行了十种生物质物种的催化和非催化裂解以产生芳族化合物和烯烃。然后调查了固有矿物质在生物质中对芳烃和烯烃催化生产的影响。最后,提出了几种提高芳族烃产率的技术。 在第一项任务中,选择10种生物质材料进行热重分析仪的研究。研究了它们的热特性和热解动力学性质。并且对最终的分析和化学成分进行了评估。结果表明,热解特性会随着加热速率的升高而发生变化。最值得注意的是,这些生物质材料热力分析图的形状是相似的;不同的是,初始最大质量损失和最终降解温度转移到了更高的温度。反应过程主要由加热速率为10℃/分钟和20℃/分钟的一阶反应和扩散模型控制,而在升高的加热速率下,反应部分地由扩散和幂律模型控制。研究发现反应最好代表各种生物质的热解动力学的模型具有活化能,其前指数因子为:甘蔗渣为103.7 KJmol-1和108秒-1,稻草为98.5 KJmol-1和107sec-1,核桃为93.99 KJmol-1和107sec-1,松木为99.68KJmol-1和107sec-1,竹为108.23KJmol-1和1013sec-1,柏树为122.56KJmol-1和109sec-1,130KJmol -1和1010秒-1和94.3 KJmol-1和107秒-1。生物质组分的活化能和前指数因子在本工作中使用的所有实验条件下显示出高反应性动力学参数。然而,木质素能够在更宽的温度范围内分解,并且在所有条件下都具有非常小的前置因子。 其次,使用HZSM-5催化剂上的流化床反应器和沙子作为床料,进行了十种生物质物种的催化和非催化快速热解(CFP和非CFP)转化为烯烃和芳烃化合物的实验。研究了生物质类型和组成(纤维素,半纤维素和木质素)对热解产物的产率和选择性的影响。 CFP和非CFP产品产量差异很大。在非CFP测试期间,最高的芳烃碳产量仅为1.34%(玉米芯)。而在CFP试验中,芳烃产率显著提高,松木、玉米芯和杨树分别为生物量的12.12%,12.52%和12.58%。主要芳族化合物为苯,其他选择性产物为49.6%(甘蔗渣),46.8%(稻草),48.0%(坚果壳)和50.78%(玉米芯)。此外,最高的CFP烯烃碳产量分别为10.19%(松柏),10.69%(玉米芯)和9.89%(杨树),与最高的非CFP烯烃相比,碳产量较低,分别为3.37%(甘蔗渣),2.85%)和2.82%(简单的)。而在松木,竹,印度和白杨中,乙烯的碳选择率分别为50.31%,59.46%,54.59%和51.67%。富含纤维素和半纤维素的生物质原料比具有较高木质素含量的生物质原料具备更高的烃产量。因此,生物质组成可用作选择生物质和预测热解产物分布的标记。 在第三次尝试中,在流化床反应器中进行了甘蔗渣(预处理和未处理)在HZSM-5沸石催化剂下的催化快速热解(CFP)转化。比较预处理和生物质材料的碳氢化合物产量和选择性,以确定无机物质对芳族化合物和烯烃产率的影响。此外还研究了反应温度(RT)和吹扫气体流速(SGFR)对芳烃和烯烃产率和选择性的影响。结果表明,在预处理甘蔗渣的CFP中,最佳气体流量为2.5 Lmin-1,温度为500oC时,芳烃产率达到12.41%。在相同的CFP条件下,最高的烯烃产率为10.89%。苯和乙烯分别是芳烃和烯烃中的主要化合物。苯的最高选择性为46.44%,而乙烯的选择性最高为45.45%。从未经处理的生物质的CFP获得的芳烃和烯烃产率略低分别为11.77%和9.9%。最后,比较了未处理和处理过的甘蔗渣中芳烃和烯烃的产率;并且比较了在最佳条件下的产率和选择性。结果表明,无机物质对烃类生产具有抑制作用,并通过堵塞催化剂孔引起催化剂失活。显然在HZSM-5催化下,去除无机物质会增加CFP期间的液体和烃产量。另烃产量和选择性不仅仅取决于温度和扫气量,而且还取决于处理过程的剧烈程度。 最后,通过HZSM-5,USY和双催化剂布置,进行蔗渣(BG)和生物塑料(BP)(鸡羽角蛋白)及其混合物的共热解生产芳烃。研究了温度,共同进料比,进料 - 催化剂比以及双催化剂设计对烃产率和选择性的影响。结果表明,在所有研究中,芳烃产率总体上有所改善。当温度从400-700℃变化时,芳烃增加10倍。而其他情况下共同进料时芳烃产率增加为1.5倍;进料/ HZSM-5比例为1:6时增加为2倍;进料/ USY比为1:16时增加为1.21倍; HZSM-5/USY配置下为0.7倍; USY / HZSM-5配置下为2.66倍。苯的选择性以较高的比例增加,而甲苯的选择性呈现相反的趋势。二甲苯选择性对共同进料比率的变化较不敏感。随着两种催化剂的催化剂比例的增加,芳族产率先增加后降低。对于HZSM-5催化剂,以1:6的进料-催化剂比可获得最佳的芳族产率,而USY催化剂的最佳进料-催化剂比为1:16。甘蔗渣的非CFP根本不产生芳烃。而HZSM-5产生较高的芳烃产率。相比之下,USY催化剂只生产甲苯和二甲苯等烃类。双催化剂设计(USY / HZSM-5)可获得最高的芳烃产率。热解温度是碳氢化合物生产的重要参数。BG和BP的共同进料增强了生物质转化为芳族化合物的转化率。对于任何类型的沸石催化剂,都存在产生最大烃的最佳进料 - 催化剂比。双催化剂布局揭示了将生物质材料有效转化为碳氢化合物的新机会。
英文题目 Catalytic Fast Pyrolysis of Different Biomass Feedstocks to Produce Aromatics and Olefins
英文主题词 Biomass, Catalyst, Fluidized ractor, Aromatics, Olefins
英文摘要 Lignocellulose biomass has the potential to be transformed into biofuels and chemicals initially obtained from fossil-based materials. Although all biomass types can be thermally and biochemically converted into biofuels and chemicals, there is significant variation among types and compositions which makes challenging and less attractive to be efficiently converted into hydrocarbons. Fossil fuels depletion and environmental concern drive the search for an alternative energy source such as biomass which abundant and environment-friendly. Catalytic fast pyrolysis is a very promising technique for solid biomass conversion into high-value chemicals products such as aromatics and olefins in a single reactor and step. In this work, the first task was to characterize various biomass materials used in the study. Secondly, catalytic and non-catalytic pyrolysis of ten biomass species to produce aromatics and olefins were conducted in the fluidized bed reactor. The third undertaking was to investigate the effects of inherent mineral matters in the biomass on the catalytic production of aromatic and olefins. Finally, several techniques to improve the yields of aromatics hydrocarbons were proposed. In the first task, ten biomass materials were selected for investigation in the thermogravimetric analyzer. The thermal characteristics and pyrolysis kinetics were investigated. In addition to proximate, ultimate analysis and chemical composition were evaluated. The results revealed changes in the pyrolysis characteristics with the rise in heating rates. Most notably, the shapes of thermograms were similar; however, the initial, maximum mass loss and final degradation temperatures shift to higher temperatures. The reaction processes are predominantly controlled by the first-order reaction and diffusion models at heating rates of 10°C/min and 20°C/min, while at elevated heating rates the reactions are partly controlled by diffusion and power law models. It was found that reaction the models best representing the pyrolysis kinetics of various biomass were having activation energies and pre-exponential factors were: 103.7 KJmol-1 and 108 sec-1 for bagasse, 98.5 KJmol-1 and 107sec-1 for rice straw, 93.99 KJmol-1 and 107 sec-1 for walnut, 99.68 KJmol-1 and 107 sec-1 for Pinewood, 108.23 KJmol-1 and 1013 sec-1 for bamboo, 122.56 KJmol-1 and 109 sec-1 for cypress, 130 KJmol-1 and 1010 sec-1 and 94.3 KJmol-1 and 107 sec-1 for poplar respectively. The activation energies and pre-exponential factors for the biomass components showed high reactivity based kinetics parameters at all the experimental conditions used in this work. However, lignin decomposed over a wider temperature range and has very small pre-exponential factors at all conditions. Secondly, the catalytic and non-catalytic fast pyrolysis (CFP and non-CFP) conversion of the ten biomass species into olefins and aromatics compounds were conducted using a fluidized-bed reactor over HZSM-5 catalyst and sand as bed materials. The influence of biomass type and composition (cellulose, hemicellulose, and lignin) on the yield and selectivity of pyrolysis products was investigated. There was a great difference between CFP and non-CFP products yield. The highest aromatics carbon yield was only 1.34% (corncob) during non-CFP tests. While a remarkable improvement in aromatics carbon yields were 12.12 %, 12.52 %, and 12.58 % obtained from pinewood, corncob and poplar biomass during CFP tests, respectively. The dominant aromatic compound was benzene with selectivities of 49.6% (bagasse), 46.8% (rice straw), 48.0% (nutshell) and 50.78% (corncob). Moreover, the highest CFP olefins carbon yields were 10.19 % (pinewood), 10.69% (corncob) and 9.89 % (poplar), compared to highest non-CFP olefins carbon yields were low as 3.37% (bagasse), 2.85% (rice straw), and 2.82% (nutshell). While the higher carbon selectivities toward ethylene were 50.31 %, 59.46 %, 54.59 % and 51.67 % in pinewood, bamboo, indus, and poplar, respectively. The biomass feedstock rich in cellulose and hemicellulose content produce higher hydrocarbon yields than those with higher lignin content. Thus biomass composition can be used as markers for selecting biomass and predicting pyrolysis products distribution. In the third endeavor, the catalytic fast pyrolysis (CFP) conversion of sugarcane bagasse (pretreated and untreated) over HZSM-5 zeolite catalyst were conducted in the fluidized-bed reactor. To compare the hydrocarbons yields and selectivities of pretreated and raw biomass materials in order to determine the effect of inorganic matter on the aromatics and olefins yields. The effects of reaction temperatures (RT) and sweeping gas flow rates (SGFR) on aromatics and olefins yields and selectivities were studied. The results showed a maximum aromatic yield of 12.41 % carbon was obtained during CFP of pretreated bagasse at an optimum gas flow rate of 2.5 Lmin-1 and temperature of 500 oC. While the highest olefin yield was 10.89 % carbon under the same CFP conditions. Benzene and ethylene were the dominant compounds in the aromatics and olefins respectively. The highest selectivity to benzene was 46.44 %, while that of ethylene was 45.45 % carbon. Slightly lower aromatic and olefin yields of 11.77 % and 9.9 %, respectively, were obtained from CFP of untreated biomass. In the last part, the yields of aromatics and olefins for the raw and treated bagasse were compared; and in addition to the yields and selectivities at optimum conditions were compared. The results suggest that inorganic matters have an inhibiting effect on hydrocarbons production and also caused catalyst deactivation by blocking the catalyst pores. It is evident that removal of inorganic matter would increase both liquid and hydrocarbon yields during CFP over HZSM-5. Hydrocarbon yields and selectivities were found not to depend only on temperature and sweeping gas flow rate, but also on the treatment process severity. Lastly, the co-pyrolysis of bagasse(BG) and bio-plastic(BP) (chicken feather keratin) and their mixtures were conducted to produce aromatic hydrocarbons over an HZSM-5, USY, and dual catalysts layout. The effects of temperature, co-feeding ratios, feed-to-catalyst ratios and dual catalyst design on hydrocarbons yields and selectivities were investigated. The results showed general improvement in the aromatic hydrocarbons yields in all cases being studied. The aromatic hydrocarbons increase by 10 times when the temperature was changed from 400 – 700C. While the aromatics yields increase in the other cases were 1.5 times at co-feeding, 2.0 greater at feed/HZSM-5 ratio of 1:6, 1.21 higher at feed/USY ratio of 1:16, 0.7 times at HZSM-5/USY layout and 2.66 times at USY/HZSM-5 scenario. The selectivities towards benzene increase at higher ratios, while that of toluene showed an opposite trend. Xylenes selectivities were less sensitive to the changes in co-feeding ratios. The aromatic yields increase and then decrease with increasing feed-to-catalyst ratios for both catalysts. For HZSM-5 catalyst, the optimum aromatic yield was obtained at 1:6 feed-to-catalyst ratios, while that for USY catalyst was 1:16. Non-CFP of bagasse produced no aromatic hydrocarbons at all. While the HZSM-5 generated higher yields of aromatics. In contrast, the USY catalyst only produced toluene and xylenes and other hydrocarbons. The dual catalyst design (USY/HZSM-5) resulted in the highest aromatic hydrocarbons yields. The pyrolysis temperature is a significant parameter for hydrocarbons production. Co-feeding BG and BP enhance biomass conversion to aromatic compounds. For any type of a zeolite catalyst, there is an optimum feed-to-catalyst ratio that generates maximum hydrocarbons. Dual catalyst layout showed a new opportunity for efficient conversion of biomass materials into hydrocarbons
学术讨论
主办单位时间地点报告人报告主题
Southeast University 2016-11-15 School of Energy and Environment Peter Keliona Catalytic pyrolysis of different biomass to produce hydrocarbons
Southeast University 2015-07-08 School of Energy and Environment Peter Keliona Fast pyrolysis of biomass and their components: pyrolysis characteristics and kinetics
Southeast University 2015-12-17 School of Energy and Environment Peter Keliona Research Proposal
Southeast University 2016-11-04 School of Energy and Environment Peter Keliona Py-GC/MS experimental results
Southeast University 2016-11-06 School of Energy and Environment Peter Keliona Co-pyrolysis of bagasse and bioplastic(Chicken feathers)
Southeast University 2016-12-19 School of Energy and Environment Peter Keliona Techniques to enhance hydrocarbons production
Southeast University 2016-12-25 School of Energy and Environment Peter keliona Semester progress report
Southeast University 2017-3-25 School of Energy and Environment Peter Keliona Comparison of catalytic and non-catalytic pyrolysis of biomass
     
学术会议
会议名称时间地点本人报告本人报告题目
National symposium of combustion 2017-Sept 13-15 Southeast University Combustion
The first International Symposium on BioEnergy and Environment (BEE 2017) 2017 July 9-12 Tainjin University, China Improving hydrocarbons production via Co-pyrolysis, single, and dual catalyst layout
The 4th International Conference on Environment Enhancing Energy 2016 July 06-08 China Agricultural University Comparison of catalytic and non-catalytic pyrolysis of ten typical biomass feedstocks to produce aromatics and olefins in a fluidized-bed reactor
5th International Conference on biorefiner- Towards Bioernergy(ICBB2015) 2015 August 10-12 Vancouver, Canada Co-firing Biomass and Coals
     
代表作
论文名称
Co-Firing Behaviors and Kinetics of Different Coals and Biomass
Influence of Inorganic Matter in Biomass on the Catalytic Production of aromatics and Olefins
Comparison of catalytic and non-catalytic pyrolysis of ten typical biomass materials to produce arom
 
答辩委员会组成信息
姓名职称导师类别工作单位是否主席备注
朱跃钊 正高 教授 博导 南京工业大学
周宏仓 正高 教授 硕导 南京信息工程大学
肖国民 正高 教授 博导 东南大学
仲兆平 正高 教授 博导 东南大学
熊源泉 正高 教授 博导 东南大学
      
答辩秘书信息
姓名职称工作单位备注
张会岩 副高 副教授 东南大学