分级孔HZSM-5催化烘焙预处理杨木快速热解制取芳烃

采用NaOH溶液对HZSM-5进行处理,通过XRD,BET,NH3-TPD方法对改性前后的HZSM-5进行表征。在管式炉中对杨木进行烘焙预处理,利用改性前后的HZSM-5在催化剂评价装置中进行烘焙预处理杨木的催化热解实验,探究杨木烘焙预处理温度和HZSM-5碱处理浓度对芳烃产物的影响。研究结果表明,碱处理后的HZSM-5形成了含有微-介孔的分级孔道结构,酸分布有所变化;随着NaOH浓度的增加,生物油中多环芳烃的含量逐渐降低,单环芳烃的含量呈现先增加后降低的趋势,在0.3-HZSM-5催化下达到最高产率58.12%;随着烘焙温度的升高,生物油中单环芳烃的含量先增加后降低,含氧化合物的含量先减小后增加,260℃烘焙预处理杨木催化热解效果最佳,芳烃化合物总收率达到82.01%,其中单环芳烃选择性达到70.87%。     

碱脱硅改性的HZSM-5分子筛催化裂解小球藻的研究

用NaOH水溶液对HZSM-5分子筛进行脱硅改性。通过XRD、N_2物理吸附、NH_3-TPD对脱硅前后的HZSM-5分子筛进行表征,并研究脱硅改性前后分子筛对小球藻催化裂解的影响规律。结果表明:在适宜的温度和相同的碱处理时间下,改变NaOH水溶液的浓度,能调节分子筛晶体中产生的介孔比例并改变分子筛酸性能;以0.3 mol/L NaOH溶液在80℃下处理2 h改性制备的HZSM-5分子筛催化剂,其表面酸量增加、酸强度降低,有利于反应;小球藻催化热解产物中的氧大部分以CO和CO_2的形式脱除,可有效降低生物油的含氧量;裂解液体产率和生物油热值分别为46.83%、32.851 MJ/kg,生物油中烃类物质总量达到40.34%(质量分数),羰基化合物和醇类物质明显减少。     

Ga改性HZSM-5分子筛催化2-甲基呋喃和甲醇制备芳香烃

采用等体积浸渍法在HZSM-5分子筛上引入Ga₂O₃，探究Ga改性HZSM-5分子筛对2-甲基呋喃（MF）和甲醇在固定床反应器中进行偶合反应的产物分布的影响。采用XRD、HTEM、BET和NH₃-TPD对催化剂的理化性质进行表征，结果显示，Ga的负载使得HZSM-5比表面积和孔容减小，改变了HZSM-5的酸类型及酸位强度分布。偶合反应结果表明，Ga的负载能够促进MF和甲醇的转化，Ga/HZSM-5不仅可以提高芳香烃的产率，而且提高了芳香烃产物中BTX的选择性。与HZSM-5相比，0.1%Ga/HZSM-5在反应温度为500℃、MF与甲醇摩尔比为1∶2、WHSV为2 h⁻¹反应条件下，使芳香烃产率从14.6%提高到23.7%，而BTX的选择性则从55.2%提高到67.8%。     

改性HZSM-5催化玉米秸秆与HDPE共热解制轻质芳烃

为提高生物质与聚乙烯共热解中苯、甲苯、乙苯、二甲苯和萘(简称)BTEXN和轻烯烃的产量，同时抑制C⁺₂₁蜡的形成，通过TG-MS/FTIR和Py-GC/MS探究催化共热解中HZSM-5和改性HZSM-5对玉米秸秆和HDPE相互作用的影响，并对BTEXN进行定量分析。结果表明，在HZSM-5的催化共热解中，HZSM-5可促进玉米秸秆与HDPE之间的相互反应，芳烃和轻烃产率增加。相比HZSM-5，在改性HZSM-5的催化共热解中，改性HZSM-5可促进轻烯烃、C₅-C₁₁脂肪烃和芳烃的析出，并抑制C⁺₂₁蜡的形成。Cu、Fe和Ce改性可促进单环芳烃的形成，同时提高BTEXN产量，相比HZSM-5分别提高20.99、25.43和20.89 mg/g，而P改性会抑制BTEXN形成。对于形成芳烃的Diels-Alder反应，Fe和Ce改性表现出较强的催化效果，而Cu改性对烃池反应催化效果较强。此外积碳分析表明，Fe和P改性具有较强的抗积碳能力。     

松木生物质催化加氢热解控制BTXN产物分布研究

在双颗粒流化床连续热解反应装置(PPFB)中考察松木生物质在MS-5A、MS-13X和HZSM-5分子筛作用下的催化加氢热解产物分布和收率并与SiO_2条件下的结果进行比较。结果表明:分子筛的孔道结构能促进松木生物质催化加氢热解的二次气相分解反应,有效控制其催化加氢热解的产物分布;MS-5A孔径(5?)过小,对轻质芳烃化合物(HCL)苯、甲苯、二甲苯和萘(BTXN)的选择性不高;大孔径(10?)的MS-13X对轻质芳烃具有较好的选择性;孔径介于MS-5A和MS-13X之间的HZSM-5的催化热解加氢过程,不仅可获得较高的HCL收率,还可得到较好分布的轻质碳氢化合物气体(HCG)产物,973 K时,其HCL和HCG收率分别为3.44%和14.98%。     

内循环串行流化床生物质催化热解试验研究

在处理量为0.2 kg/h的新型内循环串行流化床(IIFB)上进行了生物质催化热解制油的试验研究.以木屑为原料、石英砂为热载体,研究了在没有催化剂条件下反应温度对热解产物分布的影响;以HZSM-5催化剂与石英砂混合物为床料进行了催化热解试验,并对热解产物和反应后的催化剂进行了表征分析.结果表明:反应温度为515℃时,液体产物的收率最高.HZSM-5催化剂的加入促进了气体以及焦炭的生成,使液体产物的收率降低,且催化剂体积分数越大,影响越显著.催化荆表面的积炭经燃烧反应后被除去,催化剂的稳定性得到改善.热解不可冷凝气体的主要成分为CO和CO2,随着热解温度的升高,CO2产量下降,CO和CH4的产量增加.经HZSM-5催化热解后,生物油中的酸、醛和酮类物质含量明显减少,而小分子的烃类与酚类物质含量明显增加,表明催化剂具有明显的脱氧效果.     

Na_2CO_3处理HZSM-5分子筛在线催化生物质热解焦油的研究

用不同浓度Na_2CO_3溶液处理HZSM-5分子筛,采用X射线衍射(XRD)、N2吸脱附测试(BET)、吡啶吸附红外光谱(Py-IR)表征改性前后的分子筛。利用改性前后的HZSM-5在两段式固定床反应器上进行生物质热解产物在线催化试验,并对得到的生物油有机相进行理化特性和组成成分分析。结果表明,经过Na_2CO_3溶液处理后的HZSM-5分子筛介孔孔容和外比表面积增加,同时保留HZSM-5的MFI结构并改变分子筛的酸分布。随着Na_2CO_3溶液浓度的增加,生物油有机相产率和运动黏度不断减小,含氧化合物和羰基类化合物含量先减小后增加。经3 mol/L的Na_2CO_3溶液处理后的HZSM-5分子筛制得的生物油中,有机相热值达到35.3 MJ/kg,烃类物质含量达到46.27%,含氧化合物和羰基类化合物含量分别减少了27.6%和41.7%。     

中药渣固废的碳酸钾催化热解特性与产物分布规律

以木本中药渣为原料,采用浸渍法负载不同含量K₂CO₃催化剂;通过热重实验,分析中药渣催化热解特性和热解特征参数,并采用Starink法进行动力学分析,计算催化热解反应的表观活化能;使用固定床热解炉,优化催化热解反应条件,考察不同K₂CO₃负载量对热解产物分布的影响规律。热重结果表明,K₂CO₃能显著降低中药渣的初始热解温度和最大热解温度,从而降低热解快速失重段的反应活化能;且K₂CO₃负载量越大,催化热解效果越好。热解实验证实：K₂CO₃含量为中药渣催化热解反应的最主要影响因素,它可加速生物基大分子的低温解聚和热解中间产物的催化裂解,既可降低热解油产率,又能大幅提升H₂、CO和C₂H₆等小分子低碳烃气体的产率,且有利于提高热解气的H₂/CO比例。     

Py-GC/MS技术用于Chaetoceros sp. 硅藻的催化热解研究

采用热裂解−气质联用（Py-GC/MS）技术研究Chaetoceros sp. 硅藻粉末的催化热解特性。以HZSM-5为催化剂,考察了不同Si/Al比的HZSM-5催化剂对硅藻热解产物的影响,并考察了催化剂的使用量、热解升温速率、热解反应时间对产物的影响。结果表明：未加催化剂时,硅藻热解产物以脂肪酸为主,含量为50.05%,苯系物含量仅为0.87%;加入HZSM-5催化剂后,硅藻热解产物中脂肪酸含量减少,芳香类化合物显著增加。热解实验结果发现,Si/Al比为38、硅藻和HZSM-5比例为1∶9、热解速率10 000℃/s、热解时间为10 s时,能得到较理想的热解产品,其中苯系物产率可达57.76%,脂肪酸含量为2.63%。这说明HZSM-5（38）具有较好的脱氧和芳构化功能,有利于硅藻催化热解生成高品质的生物油产品。     

黄铁矿在CO2气氛下非等温氧化转化及动力学分析

针对煤中常见含铁矿物黄铁矿在富氧燃烧典型气氛下转化特性,通过同步热分析结合烟气分析研究了黄铁矿在CO₂气氛下的转化行为．结果发现,黄铁矿在CO₂气氛下主要经历5个失重阶段且均为吸热过程,首先是黄铁矿颗粒表面硫脱除的起始热解段(相界面反应,n=1/2),活化能低于其在N₂气氛下近30 k J/mol,为220.27 k J/mol,随后裂解成磁黄铁矿(三维扩散,n=1/2)活化能与其在N₂(177.27 k J/mol)下接近为178.1 k J/mol;温度高于690℃,随着升温磁黄铁矿缓慢失硫,CO₂逐渐参与磁黄铁矿转化且释放SO₂和CO;820～1 150℃经历双峰失重峰阶段,820～1 020℃,氧化气体产物SO₂大量生成且在约1 000℃达到体积浓度峰值;最后1 020～1 150℃,坩埚中残留物大量与CO₂持续氧化反应失重形成SO₂和CO,坩埚中形成复杂物相体系,铁硫化物和铁氧化物...     

双金属共改性沸石催化杉木热解制备轻质芳烃

以杉木为原料在金属改性分子筛作用下进行热解制备芳烃,采用热裂解-气相色谱质谱法进行热解。结果表明：单金属改性中5%Zn/HZSM-5可达到最好催化效果,其芳烃的相对峰面积达到最高的34.17%,苯、二甲苯的产率相对最高;与单金属改性相比,1%Zn-4%Co/HZSM-5可增大单环芳烃产率,其中苯增大1.19倍,甲苯增大1.21倍;萘、甲基萘等大分子芳烃产率显著减小,同时氧化物产率减少。验证不同金属结合会产生某种协同效应,在热解过程中添加双金属改性分子筛有利于热解油品位的提高。通过NH₃-TPD表征和BET测试阐述金属改性对催化剂表面结构及酸位点变化的影响。     

Influence of metal (Fe/Zn) modified ZSM-5 catalysts on product characteristics based on the bench-scale pyrolysis and Py-GC/MS of biomass

In this study, sawdust was selected as the raw material for biomass pyrolysis to obtain organic products. The catalyst was modified with two elements (Fe and Zn). Through analysis of the catalytic products, we attempted to identify a pyrolysis catalyst that can improve the yield of aromatic hydrocarbon products. ZSM-5, modified with Fe and Zn, was investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and Brunauer–Emmett–Teller (BET) measurements. Tube furnace and flash pyrolysis-gas chromatography-mass spectrometry (Py-GC/MS) were used to comprehensively investigate the characteristics of the products of biomass pyrolysis. The highest yield of phenols was obtained using the Fe-modified ZSM-5 catalyst, which was 18.30% higher than the yield obtained by the pure ZSM-5 catalyst. The lowest yield of acid products was obtained by single-metal-supported catalytic pyrolysis with Fe or Zn, which was 50.66% lower than the yield obtained by direct pyrolysis. During the pyrolysis of biomass using metal-modified catalysts, the production of aromatic hydrocarbons was greatly improved. Among them, compared with direct pyrolysis, the Fe-Zn co-modified ZSM-5 catalyst exhibited the weakest promotion of aromatic hydrocarbon formation, but there was still a 68.50% improvement. Although the co-modified catalyst did not show absolute advantages under the conditions used for this experiment, the improvements in the production of aromatics and phenolic products also showed its potential for improving bio-oil products. Under the action of Fe-modified catalysts, the most abundant components in the gas product were CO and CO₂, which reached levels as high as 53.45% and 15.34%, respectively, showing strong deoxidation capabilities. Therefore, Fe-modified ZSM-5 catalysts were found to better promote the formation of aromatic hydrocarbon products of biomass pyrolysis.     

活化剂种类对生物质活性炭理化特性的影响

采用KOH、K2CO3和ZnCl2为活化剂,椰壳、竹子、杨木和棉秆为原材料制备活性炭,研究不同活化剂对生物质热解活化产物及活性炭理化特性的影响.结果表明,KOH活化时,生物质的固液气三相比例均衡,CO体积产量最高,活性炭的表面官能团稳定性最好,骨架破碎,微孔结构发达,微孔面积可达749.90 m2/g.K2CO3活化时...     

Catalytic upgrading pyrolysis vapors of Jatropha waste using metal promoted ZSM-5 catalysts: An analytical PY-GC/MS

HZSM-5 with high surface area of 625 m²/g was successfully synthesized by hydrothermal method at 160 °C for 72 h. The metal promoted on HZSM-5 catalyst was prepared by liquid ion exchange method. From XRD results, the addition of metals such as Co and Ni did not change the HZSM-5 structure. The metal/HZSM-5 showed lower crystallinity and surface area than the parent HZSM-5 because of the metal dispersion on the HZSM-5 surface. The metal contents of Co/HZSM-5 and Ni/HZSM-5 detected by EDX were less than 1 wt%. Catalytic fast pyrolysis of Jatropha waste using HZSM-5 and metals/HZSM-5 was investigated in terms of biomass to catalyst ratios (1:0, 1:1, 1:5 and 1:10) and types of metals (Co and Ni). From the results, it can be concluded that both biomass to catalyst ratios and the presence of metals had an effect on the increase in aromatic hydrocarbons yields as well as the decrease in the oxygenated and N-containing compounds. Both Co/HZSM-5 and Ni/HZSM-5 promoted the production of aliphatic compounds. Additionally, the PAHs compounds such as napthalenes and indenes, which caused the formation of coke, could be inhibited by metal/HZSM-5, particularly, Ni/HZSM-5. Among catalysts, Ni/HZSM-5 showed the highest hydrocarbon yield of 97.55% with N-containing compounds remained only 1.78%. The formation of hydrocarbon compounds increased the heating values of bio-oils while the elimination of the undesirable oxygenated compounds such as acids and ketones could alleviate problem regarding acidity and instability in bio oils.     

Catalytic conversion of particle board over microporous catalysts

Catalytic pyrolysis of particle board, a type of waste wood that is increasingly produced all over the world, was carried out over three types of zeolite catalysts: HBETA, HZSM-5, and Ga-impregnated HZSM-5 (Ga/HZSM-5). Experiments conducted using a batch reactor showed that the bio-oil yield and gas yield in catalytic pyrolysis were lower and higher than those in non-catalytic pyrolysis, respectively. Analysis of the bio-oil using pyrolysis gas chromatography/mass spectrometry (Py-GC/MS) showed that the yields of high-value-added species such as aromatics and phenolics were increased to a large extent by catalytic upgrading, thus increasing the value of the product bio-oil. In particular, HZSM-5 exhibited high selectivity for aromatic compounds, and impregnation of Ga further increased the selectivity. HBETA could cause levoglucosans to decompose completely owing to its large pore size, resulting in increased yields of low-molecular-mass species.     

Enhancing the aromatic hydrocarbon yield from the catalytic copyrolysis of xylan and LDPE with a dual-catalytic-stage combined CaO/HZSM-5 catalyst

The high concentration of oxygenated compounds in pyrolytic products prohibits the conversion of hemicellulose to important biofuels and chemicals via fast pyrolysis. Herein CaO and HZSM-5 was developed to convert xylan and LDPE to valuable hydrocarbons by thermogravimetric analysis (TGA) and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) and elucidate the reaction mechanism were also investigated in detail. The results indicated that xylan/LDPE copyrolysis was more complicated than pyrolysis of the individual components. LDPE hindered the thermal decomposition and aromatic hydrocarbon formation from xylan at temperatures under 350 °C and had a synergistic effect at high temperatures. 50% LDPE was proven to be more beneficial than other percentages for the formation of monocyclic aromatic hydrocarbons. Simultaneously, the addition of CaO/HZSM-5 significantly reduced the reaction Ea and increased the reaction rate. CaO can effectively improve the deoxygenation and aromatization reaction, enhancing the yield and selectivity of aromatics to a certain extent. The maximum yield of hydrocarbons (96.01%), mono-aromatic hydrocarbons (88.53%) and S_BTXE (85.79%) were obtained at a CaO/HZSM-5 ratio of 1:2, a pyrolysis temperature of 450 °C, a catalytic temperature of 550 °C, a catalyst dose of 1:2 and a xylan-to-LDPE ratio of 1:1 via an ex situ process. The system was dominated by toluene, xylene and alkyl benzene. Diels-Alder reactions of furans and hydrocarbon pool mechanism of nonfuranic compounds improved aromatic formation. This study provides a fundamental for recovering energy and chemicals from pyrolysis of hemicellulose.     

纤维素催化热解定向调控制取不含氧烃类液体燃料

为了将生物质能高效转化为高品位不含氧的液体燃料,以纤维素为例,研究了以催化热解方式将热解产物转化为芳香烃类液体燃料的过程.实验发现,纤维素热解产生的含氧有机小分子,可以通过催化热解的形式高效转化为不含氧的芳香烃类液体.催化剂采用HZSM-5(23)、催化剂原料质量比例为5∶1、热解温度为650℃、升温速率为10000 K/s的工况为纤维素催化热解的最佳工况,单环芳烃、多环芳烃产率分别为9.90%和12.91%,总芳香烃类产率为22.81%.热解温度提升至650℃前,更高的热解温度能获得更高的芳香烃产率.继续提高热解温度,单环芳烃、多环芳烃分子间还可能进一步发生聚合反应,最终产生积碳.同时本文也提出了一种可行的纤维素催化热解中的反应途径,与本文实验结果较为匹配.     

Upgrading of a wood-derived oil over various catalysts

The upgrading of a bio-oil using a fixed bed micro-reactor operating at 1 atm, 3.6 WHSV and 330–410°C over various catalysts is reported. The catalysts used were HZSM-5, silicalite, H-mordenite, H-Y and silica-alumina. The yield of hydrocarbons as well as the extent of deoxygenation, coke formation and conversion of the non-volatile portion of the bio-oil were used as measures of catalyst performance. The maximum hydrocarbon yield when HZSM-5 was used occurred at 370°C and was 39.3 wt% of the bio-oil. For the other catalysts, the hydrocarbon yields increased with temperature and were up to 22.1 wt% for silicalite; 27.5 wt% for H-mordenite; 21.0 wt% for H-Y; and 26.2 wt% for silica-alumina at 410°C. The hydrocarbon selectivity with HZSM-5 and silicalite catalysts was mostly for gasoline range hydrocarbons (C₆ to C₁₂) and for H-mordenite and H-Y for kerosene range hydrocarbons (C₉ to C₁₅). The hydrocarbon fraction obtained with silica-alumina did not produce any defined distribution. The pore size, catalyst acidity and catalyst shape selectively affected the product distribution. The overall performance followed the order: HZSM-5 > H-mordenite > H/Y > silica-alumina, silicalite.