Comparative study on pyrolysis and catalytic pyrolysis upgrading of biomass model compounds: Thermochemical behaviors,kinetics, and aromatic hydrocarbon formation

In order to understand the pyrolysis mechanism, reaction kinetic and product properties of biomass and select suitable agricultural and forestry residues for the generation desired products, the pyrolysis and catalytic pyrolysis characteristics of three main components (hemicellulose, cellulose, and lignin) of biomass were investigated using a thermogravimetric analyzer (TGA) with a fixed-bed reactor. Fourier transform infrared spectroscopy (FTIR) and elemental analysis were used for further characterization. The results showed that: the thermal stability of hemicellulose was the worst, while that of cellulose was higher with a narrow range of pyrolysis temperatures. Lignin decomposed over a wider range of temperatures and generated a higher char yield. After catalytic pyrolysis over HZSM-5 catalyst, the conversion ratio increased. The ratio for the three components was in the following order: lignincellulose < biomass < xylan. The Starink method was introduced to analyze the thermal reaction kinetics, activation energy (Ea), and the pre-exponential factor (A). The addition of HZSM-5 improved the reactivity and decreased the activation energy in the following order: xylan (30.54%) > biomass(15.41%) > lignin (14.75%) > cellulose (6.73%). The pyrolysis of cellulose gave the highest yield of bio-oil rich in levoglucosan and other anhydrosugars with minimal coke formation. Xylan gave a high gas yield and moderate yield of bio-oil rich in furfural, while lignin gave the highest solid residue and produced the lowest yield of bio-oil that was rich in phenolic compounds. After catalytic pyrolysis, xylan gave the highest yield of monocyclic aromatic hydrocarbons, 76.40%, and showed selectivity for benzene and toluene. Cellulose showed higher selectivity for xylene and naphthalene; however, lignin showed enhanced for selectivity of C10 + polycyclic aromatic hydrocarbons. Thus, catalytic pyrolysis method can effectively improve the properties of bio-oil and bio-char.     

Microwave-assisted catalytic pyrolysis of cellulose for phenol-rich bio-oil production

The microwave-assisted catalytic pyrolysis (MACP) of cellulose was carried out using modified HZSM-5 catalysts for bio-oil production. The catalysts of Fe/HZSM-5, Ni/HZSM-5 and Fe–Ni/HZSM-5 were developed and characterized by the X-ray diffraction (XRD) and field-emission scanning electron microscopy (FE-SEM). The bio-oil was characterized by the Fourier transform infrared analyzer (FTIR) and gas chromatography/mass spectrometry (GC/MS). Results showed that Fe/HZSM-5 enhanced the yields of bio-oil by 11.4% and decreased the coke by about 24% compared to HZSM-5 without modification. The saccharides in bio-oil disappeared and were totally converted into phenols and low molecular compounds with the catalysis of Fe–Ni/HZSM-5. Fe–Ni/HZSM-5 showed high selectivity of phenols (20.86%) in the bio-oil. It was a unique finding because usually phenols can only be obtained by the pyrolysis of lignin, not cellulose. The formation of phenols from MACP of cellulose was probably caused by the conversion of furans to aromatics in the pores of HZSM-5, and followed by further conversion of aromatics into phenols on the external surface of HZSM-5.     

Preparation of bio-oil derived from catalytic upgrading of biomass vacuum pyrolysis vapor over metal-loaded HZSM-5 zeolites

The Fe-, Co-, Cu-loaded HZSM-5 zeolites were prepared via impregnation method. The upgrading by catalyst on biomass pyrolysis vapors was conducted over modified zeolites to investigate their catalytic upgrading performance and anti-coking performance. The Brønsted acid sites amount on Cu-,Co-loaded HZSM-5 decreased sharply, while that of Lewis both increased. The yield of liquid fraction and refined bio-oil over metal loaded ZSM-5 catalysts decreased, while that of char almost kept constant. The physical property of refined bio-oil was promoted in terms of pH value, dynamic viscosity and higher heating value (HHV). FT-IR analysis revealed that the chemical structure of refined bio-oil obtained over Fe-, Co-, Cu-loaded HZSM-5 zeolites was highly similar. The yield of monocyclic aromatic and aliphatic hydrocarbon over Fe-,Co-loaded HZSM-5 were boosted by around 2.5 times compared with original ZSM-5 zeolites. Data analysis revealed that Cu/HZSM-5 presented the worst deoxygenation ability. The anti-coking capability of Fe/HZSM-5 was obviously better, i.e., the coke content showed an approximate decrease of 38%. Thus, this study provided an efficient Fe/HZSM-5 catalysts for preparation of bio-oil derived from catalytic upgrading of biomass pyrolysis vapor.     

Development of a bifunctional Ni/HZSM-5 catalyst for converting prairie cordgrass to hydrocarbon biofuel

Ni/HZSM-5 catalysts were prepared using the impregnation method. The HZSM-5 and impregnated Ni/HZSM-5 catalysts were characterized by Brunauer–Emmett–Teller and X-ray diffraction. The HZSM-5 and Ni/HZSM-5 catalysts were used for prairie cordgrass (PCG) thermal conversion in a two-stage catalytic pyrolysis system. The products contained gas, bio-oil, and bio-char. The gas and bio-oil were analyzed by gas chromatography and gas chromatography–mass spectrometry separately. Higher heating values and elemental composition of bio-char were determined. The results indicated that 12% Ni/HZSM-5 treatment yielded the highest amount of gasoline fraction for hydrocarbons and showed a robust ability to upgrade bio-oil vapor.     

碱改性HZSM-5热解生物质模型化合物影响研究

实验采用Py-GC/MS在500 ℃下对NaOH、Na₂CO₃和有机碱（CTAB/TPAOH）改性HZSM-5催化热解生物质模型化合物的产物分布影响机制进行探究。结果表明,利用0.1 mol/L NaOH/Na₂CO₃改性HZSM-5使热解油中小分子酮、酚和酯类物质的收率有所提高,有利于碳链长度≥5产物（C_≥5）的生成;0.2 mol/L NaOH/Na₂CO₃改性HZSM-5催化剂有助于脱羰和脱羟基反应的进行,促使环状化合物开裂转化为链状化合物。TPAOH的加入使NaOH改性HZSM-5催化热解产物中酮类产物收率降至18.56%、醛类产物收率增至3.01%,并促使C_≥9产物向C_≤4转化,链状产物增加;经CTAB改性后C_≥9产物向C_5-8转化,环状产物增加。     

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%。     

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。     

Production of aromatic compounds from catalytic fast pyrolysis of Jatropha residues using metal/HZSM-5 prepared by ion-exchange and impregnation methods

Metal based-zeolite catalysts were successfully prepared by two different methods including ion-exchange and wet impregnation. HZSM-5 synthesized by hydrothermal method at 160 °C was used as a support for loading metals including Co, Ni, Mo, Ga and Pd. The metal/HZSM-5 had surface area and pore size of 530–677 m²/g and 22.9-26.0 Å. Non- and catalytic fast pyrolysis of Jatropha residues using metal/HZSM-5 were studied using an analytical pyrolysis-GC/MS at 500 °C. Non-catalytic pyrolysis vapors contained primarily high levels acid (50.7%), N-containing compounds (20.3%), other oxygenated compounds including ketones, alcohols, esters, ethers, phenols and sugars (25.0%), while generated small amount of aromatic and aliphatic hydrocarbons of 3.0% and 1.0%. The addition of synthesized metal/HZSM-5 improved the aromatic selectivity up to 91–97% and decreased the undesirable oxygenated (0.6–4.0%) and N-containing compounds (1.8–4.6%). The aromatic selectivity produced by metal-ion exchanged catalysts was slightly higher than that produced by impregnated ones. At high catalyst content (biomass to catalyst ratio of 1:10), Mo/HZSM-5 showed the highest aromatic selectivity of 97% for ion-exchanged catalysts and Ga/HZSM-5 revealed the highest aromatics of 95% for impregnated catalysts. The formation of aromatic compounds could be beneficial to improve calorific values of bio-oils. The presence of metal/HZSM-5 from both preparation methods greatly enhanced MAHs selectivity including benzene, toluene, and xylene (BTX), while substantially reduced unfavorable PAHs such as napthalenes.     

Effect of zeolite structure on light aromatics formation during upgrading of cellulose fast pyrolysis vapor

Promising technology for the conversion of cellulose to aromatics by catalytic fast pyrolysis (CFP) was investigated using five zeolite catalysts, i.e., 5A, SAPO-34, HY, BETA and HZSM-5. The relationship between the porosity and acidity of different zeolites with product selectivity was studied. The results showed that both the acidity and pore size of the zeolite significantly affected the production of aromatics and coke, especially the bio-oil composition. The bio-oils obtained over 5A or SAPO-34 (small pore<5.5 nm) have relatively high oxygen content. The BTEXN (benzene, toluene, ethylbenzene, xylenes and naphthalene) carbon yields over weak acidic zeolites of HY and BETA are only 6.5% and 9.0%, respectively. Due to the appropriate pore size distribution and acid position, HZSM-5 gave the highest BTEXN carbon yield of 21.1%. Moreover, the coke deposited on the spent zeolites was analyzed by temperature programmed oxidation. Furthermore, three possible mechanisms that the acid sites catalyze vapor towards non-condensable gases, aromatics and coke were also studied. HZSM-5 achieved satisfactory deoxygenation and aromatic production simultaneously, made it a potential catalyst for producing light aromatics from reforming the biomass pyrolytic vapors.     

Catalytic co-pyrolysis of polypropylene and Laminaria japonica over zeolitic materials

Catalytic co-pyrolysis of polypropylene and Laminaria japonica was carried out using Py-GC/MS and a fixed-bed reactor over different catalysts: HZSM-5, mesoporous MFI, Pt/mesoporous MFI, and mesoporous Al-SBA-16. The contents of oxygenates, acids, and wax species were reduced substantially by catalytic upgrading, whereas the contents of aromatics and light hydrocarbons in the gasoline and diesel range were significantly increased, enhancing the economic value of the bio-oil. Among the catalysts used in this study, Pt/mesoporous MFI showed the highest catalytic upgrading capability, which was attributed to large pore size, strong Brönsted acid sites, and the catalytic effect of added Pt.     

Non-catalytic and catalytic pyrolysis of Ulva prolifera macroalgae for production of quality bio-oil

Pyrolysis of Ulva prolifera macroalgae (UM), an aquatic biomass, was carried out in a fixed-bed reactor in the presence of three zeolites based catalysts (ZSM-5, Y-Zeolite and Mordenite) with the different catalyst to biomass ratio. A comparison between non-catalytic and catalytic behavior of ZSM-5, Y-Zeolite and Mordenite catalyst in the conversion of UM showed that is affected by properties of zeolites. Bio-oil yield was increased in the presence of Y-Zeolite while decreased with ZSM-5 and Mordenite catalyst. Maximum bio-oil yield for non-catalytic pyrolysis was (38.5 wt%) and with Y-Zeolite catalyst (41.3 wt%) was obtained at 400 °C respectively. All catalyst showed a higher gas yield. The higher gas yield might be attributed to that catalytic pyrolysis did the secondary cracking of pyrolytic volatiles and promoted the larger small molecules. The chemical components and functional groups present in the pyrolytic bio-oils are identified by GC–MS, FT-IR, ¹H-NMR and elemental analysis techniques. Phenol observed very less percentage in the case of non-catalytic pyrolysis bio-oil (9.9%), whereas catalytic pyrolysis bio-oil showed a higher percentage (16.1%). The higher amount of oxygen present in raw biomass reduced significantly when used catalyst due to the oxygen reacts with carbon and produce (CO and CO₂) and water.     

Upgrading of fast pyrolysis bio-oil to drop-in fuel over Ru catalysts

Catalyst plays a key role in the upgrading of fast pyrolysis bio-oil to advanced drop-in fuel, while the selectivity and deactivation of catalyst still remain the biggest challenge. In this study, three Ru catalysts with activated carbon, Al₂O₃ and ZSM-5 as supports were prepared and tested in bio-oil hydrotreating process. The physical properties and components of upgraded bio-oil were detected to identify the difference in catalytic performance of three catalysts. The results showed that furan, phenols and their derivatives in fast pyrolysis bio-oil could be hydrogenated to alkanes, alkenes and benzenes over Ru catalysts. The different components of oil phase over three catalysts may be resulted from the surface properties of three supports. Activated carbon supported Ru catalyst showed the best catalytic performance and was suggested to be the most promising catalyst for pyrolysis bio-oil upgrading.     

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.     

Microwave assisted catalytic pyrolysis of bagasse to produce hydrogen

Using Ni/SiC as a catalyst, bagasse was microwave-assisted pyrolysis in a homemade quartz reactor. The results showed that with the continuous increase of Ni content, the experimental catalytic pyrolysis effect on bio-oil became more and more obvious, and the hydrogen yield gradually increased. When Ni content exceeded 8%, the hydrogen yield and bio-oil catalytic pyrolysis efficiency decreased, and the lowest bio-oil yield was 9.55% when Ni content was 15%, With the increase of power, the catalytic cracking efficiency and hydrogen yield of bio-oil increased, With the increase of catalyst dosage, the catalytic efficiency and the hydrogen yield increase gradually. When the catalyst quality exceeds 1/4 of the material, the growth rate of catalytic efficiency decreases, after alkali treatment, the variation law of hydrogen yield and bio-oil is consistent with that without alkali treatment. In contrast, more hydrogen can be produced after alkali treatment. Under the optimum conditions, the hydrogen yield was 35.85 g/kg biomass.     

In-situ catalytic upgrading of biomass-derived vapors using HZSM-5 and MCM-41: Effects of mixing ratios on bio-oil preparation

In this paper, two molecular sieves with different pore sizes, namely HZSM-5 and MCM-41, were mixed using different ratios and used in the in-situ catalytic pyrolysis of rape straw. The effects of different HZSM -5 and MCM -41 mixing ratios on the quality of the bio-oil were studied by physicochemical properties, product yields and compositions. Moreover, Brunauer-Emmett-Teller (BET) catalyst analysis was performed. The results showed that the liquid yield and organic phase decreased first and then increased, whereas the gas yield showed an opposite trend. The density, O/C and kinematic viscosity of the bio-oil organic phase decreased first then increased, whereas the H/C, pH values and higher heating values initially increased, then declined. The oxygen content, H/C, O/C, kinematic viscosity, density, higher heating value and pH value of the bio-oil organic phase obtained at 1:1 mixed ratio were 12.81%, 1.701, 0.126, 5.06 mm²/s, 0.94 g/cm³, 34.31 MJ/kg and 5.41, respectively. The organic phase included numerous organic compounds, such as carboxylic acids, aldehydes, ketones, hydrocarbons, alcohols, ethers and esters. The hydrocarbon content in the bio-oil organic phase gradually increased and the carbonyl groups content gradually decreased as the MCM-41 content increased from 0 to 50%. In contrast, the hydrocarbon content gradually decreased and the carbonyl groups content gradually increased as the MCM-41 content increased from 50% to 100%. The hydrocarbon and carbonyl groups contents were 53.83% and 6.35%, respectively, at the MCM-41 content of 50%. The mixed catalyst activity increased with the increase in MCM-41 content (up to 50%), and tended to be stable once the MCM-41 contents surpassed 50%.     

The effect of oyster shell powder and rice husk ash on the pyrolysis of rice husk for bio-oil

The aim of this study was to investigate the effect of oyster shell powder (OSP) and rice husk ash (RHA) on the pyrolysis of rice husk (RH) for bio-oil. The present study focuses on the effect of catalysts on pyrolysis of RH for bio-oil and the quantity of bio-oil produced. The results showed that both OSP and RHA could improve the yield and quality of bio-oil, and the catalytic effect of OSP was better than that of RHA. With the content of the two catalysts increased, the net increase range of bio-oil yield decreased gradually. With 3 wt.% of OSP or 2 wt.% of RHA, the yield of bio-oil achieved to 57.06% and 56.07% respectively, which increased by 6.03% and 4.20% compared to that of single pyrolysis of rice husk. Both OSP and RHA can increase the bio-oil heating value and decrease the acid value. With the presence of 1–5 wt.% of OSP or RHA in the RH pyrolysis process, the heating value of the bio-oil can be increased by 5.04–10.25% and 4.32–5.78%, the acid value of the bio-oil can be decreased by 5.30–13.54% and 9.81–33.01%, respectively. OSP was better than RHA on the heating value improvement, while RHA was superior to OSP in decreasing the acid value. The gas chromatography/mass spectrometry (GC-MS) analysis of bio-oil composition indicated that the formation of phenols, acids and ketones compounds were inhibited and alcohols and furan compounds were promoted with the addition of OSP and RHA catalysts. The study made the catalytic pyrolysis process more favorable for the production of high heating value fuel.     

Optimizing Ni–Ce/HZSM-5 catalysts for ex-situ conversion of pine wood pyrolytic vapours into light aromatics and phenolic compounds

The main objective of the present work is to investigate the influence of nickel to cerium ratio on hydrogen exchanged Zeolite Socony Mobil-5 (HZSM-5) towards the catalytic upgrading of pine derived oxygenated pyrolysis vapours into aromatic hydrocarbon and phenol in pyrolysis oil via ex-situ fixed bed reactor. The presence of CeO₂ could change electron density of Ni, promote the reduction of Ni species, accelerate the transfer of carbon species, and suppress the production of carbon deposits (17.53%–25.11%) compared with the parent HZSM-5 catalyst (28.95%); it also improved the hydrodeoxygenation ability of all xNiyCe/HZSM-5(nickel and cerium bimetal modified HZSM-5) catalysts, resulting increases in noncondensable gas content (from 31.46% to 52.99%–65.53%). Ni to Ce ratio of 1:1 and 1:2 produced highest aromatic hydrocarbon (32.14%) and phenols (55.51%) relative peak areas. The acid center of HZSM-5 and the metal acid center of the Ni:Ce = 1:1 catalyst obviously fine-tuned the formation of coke; and promoted hydrocarbon production. Moreover, high Ni content promoted alkylation of benzene at C6–C9 and increased C10⁺ PAHs relative peak area; high Ce content promoted the formation of olefin and Increasing the cleavage of C–O bonds and promoted hydrogenation or dehydrogenation, reduced polycyclic aromatic hydrocarbons and coke yield, and increased phenols and alkylphenols selectivity.     

Research on Non-Thermal Plasma assisted HZSM-5 online catalytic upgrading bio-oil

In order to improve the quality of bio-oil and reduce the coking and deactivation of HZSM-5 molecular sieve catalyst in the catalytic cracking of bio-oil upgrading process, Non-Thermal Plasma (NTP) assisted HZSM-5 technical scheme was proposed, online upgrading of rape straw vacuum pyrolytic vapors were conducted in a fixed bed reactor to verify the effectiveness of the technology. In the research, the influence of catalyzing temperature, catalyst bed height, discharge power on the physicochemical properties of refined bio-oil were studied, and the yield of refined bio-oil was regarded as evaluation index, response surface methodology was adopted to optimize upgrading processing parameters. Chemical composition of the refined bio-oil which was obtained under optimized parameters was analyzed by GC–MS, and using thermogravimetric analysis, the impact of NTP on catalyst anti-coking property was evaluated. Research results indicates that catalyzing temperature, catalyst bed height and discharge power have significance effect on yield and physicochemical properties of refined bio-oil. With the optimized processing parameters of 392 °C catalyzing temperature, 34 mm catalyst bed height and 23.7 W discharge power, the oxygen content, high heating value and pH of refined bio-oil were respectively 19.79%, 33.14 MJ/kg and 4.98. Compared with original HZSM-5 catalytic upgrading method, the quality of refined bio-oil was improved obviously, and the amount of catalyst coke deposit reduced from 5.88% to 2.14%, the feasibility of NTP assisted HZSM-5 online upgrading bio-oil was confirmed.     

Selective catalytic fast pyrolysis of Jatropha curcas residue with metal oxide impregnated activated carbon for upgrading bio-oil

Jatropha curcas waste was subjected to catalytic pyrolysis at 873 K using an analytical pyrolysis–gas chromatography/mass spectrometry in order to investigate the relative effect of various metal oxide/activated carbon (M/AC) catalysts on upgrading bio-oil from fast pyrolysis vapors of Jatropha waste residue. A commercial AC support was impregnated with Ce, Pd, Ru or Ni salts and calcined at 523 K to yield the 5 wt.% M/AC catalysts, which were then evaluated for their catalytic deoxygenation ability and selectivity towards desirable compounds. Without a catalyst, the main vapor products were fatty acids of 60.74% (area of GC/MS chromatogram), while aromatic and aliphatic hydrocarbon compounds were presented at only 11.32%. Catalytic pyrolysis with the AC and the M/AC catalysts reduced the oxygen-containing (including carboxylic acids) products in the pyrolytic vapors from 73.68% (no catalyst) to 1.60–36.25%, with Ce/AC being the most effective catalyst. Increasing the Jatropha waste residue to catalyst (J/C) ratio to 1:10 increased the aromatic and aliphatic hydrocarbon yields in the order of Ce/AC > AC > Pd/AC > Ni/AC, with the highest total hydrocarbon proportion obtained being 86.57%. Thus, these catalysts were effective for deoxygenation of the pyrolysis vapors to form hydrocarbons, with Ce/AC, which promotes aromatics, Pd/AC and Ni/AC as promising catalysts. In addition, only a low yield (0.62–7.80%) of toxic polycyclic aromatic hydrocarbons was obtained in the catalytic fast pyrolysis (highest with AC), which is one advantage of applying these catalysts to the pyrolysis process. The overall performance of these catalysts was acceptable and they can be considered for upgrading bio-oil.     

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。