ZSM-5–SBA-15复合分子筛的制备

采用后合成法合成了ZSM-5–SBA-15微介孔复合分子筛,考察了m(ZSM-5)/m(SBA-15)、晶化时间、盐酸量、焙烧温度对烷基化催化性能的影响。在m(ZSM-5)/m(SBA-15)=0.2,晶化时间为18 h,盐酸量为20 m L,焙烧温度为550℃条件下,合成的复合分子筛催化剂的甲醇转化率为94.93%,对二甲苯选择性为45.46%。惰性SBA-15介孔分子筛抑制了ZSM-5外表面酸性,提高了对二甲苯的选择性。     

Mo/ZSM-5催化作用下生物质快速热解制生物油实验研究

采用等体积浸渍法制备Mo/ZSM-5催化剂,并应用于生物质快速热解制备生物油。采用Py-GC/MS装置,重点研究了Mo负载量、反应温度、反应时间和催化剂与木粉质量比等参数对生物油产率和组成的影响规律。实验结果表明,与纯木粉热解相比较,ZSM-5和Mo/ZSM-5催化作用下生物油的产率大幅提高;在反应温度为600℃、反应时间为25 s、催化剂与木粉质量比为10/1的条件下,10Mo/ZSM-5催化作用下生物油中芳香烃类化合物的产率和相对含量达到最大值。根据生物油产率和组成的变化,可以得出Mo负载的ZSM-5催化剂强化促进酸类、醛酮类等含氧化合物转化为芳香烃类化合物,有效实现了生物质热解生物油品质的提升。     

Fe-Zn共改性ZSM-5催化作用下生物质快速热解特性研究

选取木屑和花生壳作为原料进行生物质热解,研究有机产物分布,催化剂使用Fe、Zn两种金属元素进行改性。通过X射线衍射（XRD）、扫描电镜（SEM）、傅里叶红外（FT-IR）、比表面积测试（BET）对Fe-Zn改性的ZSM-5进行分析。使用闪速裂解-气质联用仪（PY-GC/MS）对原料进行热解,探究生物质催化热解的产物分布变化。催化剂的使用使得芳烃类产物产率获得较大提升,在木屑热解中,Fe负载的分子筛催化获得了酚类的最高产率,比ZSM-5催化热解产率提升18.30%。金属改性催化剂在花生壳热解中,大幅提升了芳烃类产物产率,其中Zn负载催化剂芳烃类产物产率最高,Zn负载催化热解比直接热解的酚类产率降低了18.92%。Zn负载催化获得了最低的酮类产率,与直接热解相比酮类产率降低19.74%,显示出较强的脱羟基效果。此外Zn负载催化和Fe-Zn双金属负载催化在花生壳热解中都大幅降低了酸类产物产率,与直接热解相比酸类产率分别降低了30.46%、36.71%。     

KOH／SBA-15负载型固体碱催化剂的合成、表征及催化性能

采用后合成法制备出固体碱催化剂KOH／SBA-15,利用X射线衍射法（XRD）、N2吸附-脱附（BET）、透射电镜（TEM）、化学吸附剂表面碱性测定（COz—TPD）等对其进行表征。考察了其在大豆油酯交换反应制备生物柴油中的催化性能。结果表明,在相同反应条件下,与CaO／SBA-15和MgO／SBA-15相比,KOH／SBA-15在催化活性和孔扩散上都具有较大的优越性,催化制备生物柴油产率最高（83．56％）。     

生物质与废轮胎共热解及催化对热解油的影响

生物质稻壳与废轮胎以不同比例组成的均匀混合物在管式固定床内共热解,MCM-41和SBA-15作为催化剂,对产生的热解油性质进行了研究。结果表明,随着废轮胎在混合物中比例增加,热解油产率和热值在增加,而黏度和密度在降低。当稻壳占到60%（质量）时,热解液体产率为44.5%（质量）,热解油热值为40 MJ·kg-1,热值与柴油接近;温度对热解油的产率和组分柠檬精油的生成影响较大。对组成一定的混合物,在热解温度500℃时二者均达到最大。通过对热解油主要组分柠檬精油和氧含量的分析说明,共热解过程中组分间可以产生一定的相互作用,并具有协同效果,体现在柠檬精油组分的含量低于加权后的浓度,氧含量大于加权后的数值;与没有催化剂存在情况相比,MCM-41和SBA-15的存在能显著降低热解液体的黏度和密度,其中,SBA-15的降低效果更为明显。     

生物质/塑料共催化热解过程中HZSM-5失活分析

利用管式炉热解装置进行HZSM-5在线共催化热解玉米秸秆/高密度聚乙烯过程中的循环和再生利用实验,对玉米秸秆进行酸洗预处理,考察原料酸洗预处理对HZSM-5催化性能的影响。采用GC-MS（气相色谱-质谱联用仪）对生物油的化学组成进行分析,并对反应前、反应后以及再生催化剂进行TG（热重分析）、ICP-MS（电感耦合等离子体发射光谱仪）、SEM/EDS（场发射扫描电镜）、BET、NH₃-TPD（程序升温脱附技术）等表征分析。研究表明,HZSM-5催化玉米秸秆/高密度聚乙烯热解的主要产物为芳烃,随着催化剂重复利用次数的增加,芳烃含量逐渐降低,催化剂的比表面积、孔容、酸性等也随之降低,说明催化剂的活性逐渐降低;原料经酸洗预处理后有利于热解中间体的生成,加速了催化剂的结焦失活速率;催化热解酸洗玉米秸秆/高密度聚乙烯的催化剂经焙烧再生后其活性基本恢复至原有水平,而催化热解未处理玉米秸秆/高密度聚乙烯的催化剂再生后其活性有所降低,碱/碱土金属在HZSM-5催化剂上发生累积,从而引起酸性位点“中毒”失活,而原料经酸洗预处理后可有效降低催化剂上碱/碱土金属的累积量,有利于延长催化剂的使用寿命。     

ZSM-5/SBA-15催化氧化脱硫催化剂的制备表征及脱硫性能研究

结合分子筛ZSM-5与SBA-15自身的优点,合成了不同质量比例的ZSM-5/SBA-15微孔-介孔复合分子筛,并进行XRD、N2吸附-脱附表征,分析其结构特征。以其为载体负载金属W、Ni、Ce、Cu,制备出不同的氧化脱硫催化剂,对模拟油进行氧化脱硫研究。结果表明,负载金属W制备出的WO3-ZSM-5/SBA-15(ZSM-5质量分数为10%)复合分子筛,脱硫效果最好,脱硫率为75.44%。     

ZSM-5/SBA-15催化氧化脱硫催化剂的制备表征及脱硫性能研究

结合分子筛ZSM-5与SBA-15自身的优点,合成了不同质量比例的ZSM-5/SBA-15微孔-介孔复合分子筛,并进行XRD、N2吸附-脱附表征,分析其结构特征。以其为载体负载金属W、Ni、Ce、Cu,制备出不同的氧化脱硫催化剂,对模拟油进行氧化脱硫研究。结果表明,负载金属W制备出的WO3-ZSM-5/SBA-15(ZSM-5质量分数为10%)复合分子筛,脱硫效果最好,脱硫率为75.44%。     

纤维素快速热解反应气体的在线催化裂解

通过浸渍法制备MHZSM-5(M Fe,Zr,Co)催化剂,采用激光粒度分析仪、比表面积及孔径分析仪和X射线衍射仪(XRD)对催化剂的性质进行表征,并在立式两段加热炉上进行纤维素快速热解蒸汽的在线催化实验。对不同催化剂条件下的产物分布特性及生物油组成特性进行分析,结果表明,随着催化剂的引入,液相产率从52.06%最大下降至23.63%,气相产率从42.39%最大提高至70.84%,CoHZSM-5对于热解蒸汽的催化气化效果最为明显;纤维素快速热解生物油中以1,6-脱水-β-D-吡喃葡萄糖(左旋葡聚糖)为主,引入催化剂对纤维素热解蒸汽进行在线催化重整后,产物中芳烃类物质显著增加,以FeHZSM-5和ZrHZSM-5效果最佳;HZSM-5催化下生物油中左旋葡聚糖的含量提高至63.78%;催化后热解油中乙酸及丙酸含量均减少,但降低幅度有限。综合催化剂对产率及组分的影响效果来看,FeHZSM-5和ZrHZSM-5对纤维素快速热解蒸汽的催化调控作用较为显著。     

不同种类分子筛催化热解纤维素

以纤维素为原料,在固定床反应器上进行了催化热解研究。采用的催化剂分别为ZSM-5(38)、Al-MCM-41(40)、ZSM-5(38)/Al-MCM-41(40)。本研究通过改变催化剂种类,考察其对生物质热解产物及生物油成分的影响。实验结果表明:添加催化剂后,生物油产率降低,且其含水率也有所增加。与未添加催化剂相比,醇含量有明显提高。酮类、醛类、酯类、醚类、呋喃等含氧化合物及酸含量均有所降低,芳香类化合物有小幅升高趋势。     

Rapid and catalytic pyrolysis of corn stalks

Non-catalytic and catalytic rapid pyrolysis of corn stalks was studied in a tubular fixed-bed reactor. The optimum operating conditions giving the highest liquid yield was determined as pyrolysis temperature of 500 °C, sweeping gas flow rate of 400 cm³ min^− 1 and heating rate of 500 °C min^− 1. In the catalytic process, rapid pyrolysis of stalks was performed at the optimum conditions with catalysts such as ZSM-5, HY and USY. The highest liquid yield from the catalytic pyrolysis was 27.55% with ZSM-5, while the oil from non-catalytic pyrolysis was 33.30%. In the last part, various spectroscopic and chromatographic methods were applied for characterization of bio-oils. Although catalytic pyrolysis converts the long chains of alkanes and alkenes of the oils into lower weight hydrocarbons, the obtained oil yields were lower than those of non-catalytic pyrolysis. USY catalyst gives the highest amount of aromatics among the catalysts used. Moreover, TG–DTA analyses were applied on raw materials to investigate thermal degradation of corn stalks and calculate the kinetic parameters.     

Short Vapour Residence Time Catalytic Pyrolysis of Spruce Sawdust in a Bubbling Fluidized-Bed Reactor with HZSM-5 Catalysts

Catalytic pyrolysis of spruce sawdust was carried out in a bubbling fluidized-bed reactor using HZSM-5 catalysts. The effects of space velocity, catalyst deactivation, catalyst acidity and catalyst regeneration were studied. The use of catalysts decreased the yield of organic liquids compared to non-catalytic yields while the yields of pyrolytic water and gases increased. Decreasing the space velocity enhanced these effects. The rate of catalyst deactivation depended on the acidity of the catalyst, with more acidic catalysts deactivating more rapidly. Using a catalyst with a Si/Al ratio of 140 resulted in the largest changes in bio-oil properties. Periodic regeneration of the catalyst in the fluidized-bed reactor was also demonstrated using varying regeneration times and temperatures. It was shown that compared to BFB reactors, CFB reactor types would offer better operating characteristics for commercial scale catalytic pyrolysis processes in regard to vapour residence times, and catalyst activity and regeneration.     

Catalytic Pyrolysis of Pine Wood Sawdust to Produce Bio-oil: Effect of Temperature and Catalyst Additives

In this work, non-catalytic pyrolysis of Turkish pine (Pinus brutia Ten.) wood sawdust was performed in a fixed-bed reactor at various temperatures to obtain the optimum conditions to achieve a maximum bio-oil yield. The highest yield of bio-oil was obtained about 46 wt% at 550°C for non-catalytic pyrolysis. At the optimum conditions, the effects of different catalyst types (KOH, ZnCl₂, and ZnO) and amount of catalyst (5, 10, 15, and 20 wt%) on the pyrolysis product yields and bio-oil properties were investigated. The presence of catalysts changed the product distribution considerably. Increasing the amount of catalyst led to a decrease in the yield of liquid product, while the gas and char yields increased compared to non-catalytic pyrolysis. The chemical compositions of bio-oil were determined with GC-MS analyses. It was determined that bio-oils contain a large variety of organic compounds, such as furans, aldehydes, ketones, phenols, acids, benzenes, alcohols, alkanes, and polycyclic aromatic hydrocarbons (PAHs). The catalysis by KOH significantly increased the levels of phenols, while it reduced the formation of acids and aldehydes. ZnCl₂ produced bio-oil with high percentages of aldehydes. Moreover, ZnO reduced the proportion of PAH in the bio-oil. These results demonstrated that bio-oils could improve with a catalyst. Therefore, catalyst selection for high bio-oil quality is crucial in industrial applications.     

Catalytic pyrolysis of woody biomass in a fluidized bed reactor: Influence of the zeolite structure

Catalytic pyrolysis of biomass from pine wood was carried out in a fluidized bed reactor at 450 °C. Different structures of acidic zeolite catalysts were used as bed material in the reactor. Proton forms of Beta, Y, ZSM-5, and Mordenite were tested as catalysts in the pyrolysis of pine, while quartz sand was used as a reference material in the non-catalytic pyrolysis experiments. The yield of the pyrolysis product phases was only slightly influenced by the structures, at the same time the chemical composition of the bio-oil was dependent on the structure of acidic zeolite catalysts. Ketones and phenols were the dominating groups of compounds in the bio-oil. The formation of ketones was higher over ZSM-5 and the amount of acids and alcohols lower than over the other bed materials tested. Mordenite and quartz sand produced smaller quantities of polyaromatic hydrocarbons than the other materials tested. It was possible to successfully regenerate the spent zeolites without changing the structure of the zeolite.     

生物质双级催化热解制备燃料化学品的研究进展

生物质热解所得目标产物生物油因高含氧量、组分复杂等问题难以直接应用,通过使用适宜的催化剂升级热解蒸气可实现生物油的脱氧提质。本文基于前人研究,首先总结了生物质催化热解中金属氧化物和分子筛催化剂的结构特点、催化原理与催化效果。然后详细介绍了微介孔复合型、金属氧化物/ZSM-5复合型双级催化体系的构建原理、催化模式及其对于生物质催化热解产物分布规律产生的影响,并说明了双级催化体系的可行性与实用性;同时概述了影响生物质催化热解的其他因素,包括原料特性、工艺参数、操作模式等。最后针对目前双级催化热解研究与发展中存在的问题,对进行双级催化模式的比较研究、改进催化体系以降低生产成本、发掘双级催化剂的多种使用价值等方向提出了展望。     

纤维素热解生物油分子尺寸分布特性

分子筛催化剂的孔径与生物油分子尺寸之间的差异造成分子筛催化剂的择形选择性。分子筛的孔径数据来自晶体结构分析,而生物油的分子尺寸数据很难获得,对生物油的分子尺寸进行估算十分必要。采用热裂解气质联用技术(Py-GC/MS)研究了纤维素热解生物油的组成成分,以Joback基团贡献法为基础计算了纤维素热解生物油各组成成分的动力学直径,分析了纤维素热解生物油的分子尺寸分布特性。结果表明,纤维素在350~600℃热解产生生物油的主要成分为脱水糖、呋喃衍生物和酮类化合物,生物油各组成成分的动力学直径主要分布在[0.500, 0.600) nm。当热解温度由350℃升至600℃时,动力学直径位于[0.550, 0.600) nm的生物油各组成成分的峰面积百分比由88.72%降至64.53%,位于[0.500, 0.550) nm的生物油各组成成分的峰面积百分比则由2.88%升至21.95%。纤维素催化裂解制备高品质液体燃料可选用ZSM-5, ZSM-11和IM-5等孔径尺寸0.500~0.600 nm的分子筛催化剂。     

Improving hydrocarbons production via catalytic co-pyrolysis of torrefied-biomass with plastics and dual catalytic pyrolysis

To increase the low yield and selectivity of aromatic hydrocarbons during the biomass pyrolysis process, we torrefied the biomass and then co-pyrolyzing with plastics such as high-density polyethylene (HDPE), polystyrene (PS), ethylene-vinyl acetate (EVA) and polypropylene (PP) and also single and dual catalyst layouts were investigated by Py-GC/MS. The results showed that non-catalytic fast pyrolysis (CFP) of raw bagasse (RBG) generated no aromatics. After torrefaction non-CFP of torrefied bagasse (TBG) generated low aromatic yield. Indicating that torrefaction would enhance the proportion of aromatics during the pyrolysis process. The CFP of TBG_200℃ and TBG_240℃ over ZSM-5 produced the total aromatic yield of 1.96 and 1.88 times higher, respectively, compared to non-CFP of TBG. Furthermore, the addition of plastic could increase H/Ceff ratio of the mixture, consequently, increase the yield of aromatic compounds. Among the various torrefied-bagasse/plastic mixtures, the CFP of TBG/EVA (7:3 ratio) mixture generated the highest the total aromatic yield of 7.7 times more than the CFP of TBG alone. The dual catalyst layout could enhance the yield of aromatics hydrocarbons. The dual-catalytic co-pyrolysis of TBG_200℃/plastic (1:1) ratio over USY (ultra-stable Y zeolite)/ZSM-5, improved the total aromatics yield by 4.33 times more than the catalytic pyrolysis of TBG_200oC alone over ZSM-5 catalyst. The above results showed that the yield and selectivities of light aromatic hydrocarbons can be improved via catalytic co-pyrolysis and dual catalytic co-pyrolysis of torrefied-biomass with plastics.     

含油污泥在ZSM-5沸石上催化热解产物特性

采用U型固定床管式炉研究了含油污泥在ZSM-5分子筛催化剂上的热解产物特性。发现在450℃下未使用催化剂热解时,GC-MS和GC测得的油泥热解油产物中的主要成分为烷烃和烯烃,芳烃含量较低;气体产物中主要为短链烃类,氢气产量较少。而在ZSM-5分子筛的催化作用下,热解油中芳香烃产量达到88.4%,气体产物中的氢气产量和短链烃类产量均明显增加。研究了400～550℃之间分子筛对含油污泥的催化效果,发现ZSM-5在500℃时催化效果最佳,油相产率达到65.6%,油相中的沥青质和胶质含量较低,芳香烃产量达到90.9%。通过热重和XPS分析发现分子筛上的积炭主要以多环芳烃焦炭的形式存在。