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The large-scale blooming of Enteromorpha prolifera (EP) results in "green tide," triggering significant environmental issues. However, EP as algal biomass can be converted to syngas through fast pyrolysis. This research investigates the fast pyrolysis of modeled compounds of EP for syngas production. Rhamnose (Rha), glucuronic acid (GlcA), aspartic acid (Asp), glutamic acid (Glu), and alanine (Ala) are used as the model compounds. This study employs experiments and simulations on fast pyrolysis processes. The results reveal that polysaccharide sulfate (PS) undergoes various reactions, including glycosidic bond cleavage, pyran ring opening, dehydration, and C-C bond cleavage. Simultaneously, amino acids experience dehydration, deamination, decarboxylation, and decarboxylation reactions. Fast co-pyrolysis of modeled compounds of EP, the monosaccharides and uronic acid molecules produced by PS pyrolysis also attack each other with amino acid molecules to produce other substances. The pyrolysis gas obtained from the model compounds of PS exhibits the highest CO content. Notably, amino acids possess a superior capability to produce H 2 compared with PS. With the fast co-pyrolysis of EP model compounds, the CO 2 content increases while the CO content decreases. This study provides a theoretical basis for the fast pyrolysis of EP to produce syngas. [Display omitted] • Fast pyrolysis reaction processes of modeled substances of EP are conducted. • The synergistic effect between modeled substances is researched. • The H 2 and CO contents from fast pyrolysis of EP are 18.08 vol% and 25.69 vol%. [ABSTRACT FROM AUTHOR]

Abstract: Pyrolysis has been increasingly perceived as a promising technology to produce biofuel precursors (bio‐oil) from agricultural residuals; however, there is a significant quality gap between a bio‐oil and the fuels used for transportation. In this study, we autohydrolyzed pretreated sugarcane bagasse at three different conditions (180 °C–10 min, 180 °C–40 min, 200 °C–40 min), then we investigated the effect of this pretreatment on a subsequent pyrolysis stage. High‐pressure ion‐exchange chromatography (HPIC) and the 13C cross‐polarization/magic angle spinning (CP/MAS) solid‐state nuclear magnetic resonance (NMR) revealed that the autohydrolysis pretreatment significantly disrupted the hemicellulose fractions in the sugarcane bagasse and caused the breakage of lignin ether linkages in the sugarcane bagasse feedstocks. As the 31P NMR results indicated, the autohydrolysis pretreatment removed carboxylic acid groups up to 66.7 %, which could significantly address the corrosion problem of bio‐oils. Heteronuclear single quantum correlation (HSQC) analysis suggested that the autohydrolysis pretreatment effectively lowered the presence of the oxygenated aromatic compounds in the bio‐oils. Gel permeation chromatography (GPC) analysis of the bio‐oils indicated that the oils from severely pretreated sugarcane bagasse pyrolyzed at a low temperature (i.e., 400 °C) contained lower‐molecular‐weight components similar to those present gasoline products. [ABSTRACT FROM AUTHOR]

Aqueous phase hydrodeoxygenation of lignin pyrolysis oil and related model compounds were investigated using four noble metals supported on activated carbon. The hydrodeoxygenation of guaiacol has three major reaction pathways and the demethylation reaction, mainly catalyzed by Pd, Pt and Rh, produces catechol as the products. The presence of catechol and guaiacol in the reaction is responsible for the coke formation and the catalysts deactivation. As expected, there was a significant decrease in the specific surface area of Pd, Pt and Rh catalysts during the catalytic reaction because of the coke deposition. In contrast, no catechol was produced from guaiacol when Ru was used so a completely hydrogenation was accomplished. The lignin pyrolysis oil upgrading with Pt and Ru catalysts further validated the reaction mechanism deduced from model compounds. Fully hydrogenated bio-oil was produced with Ru catalyst. [ABSTRACT FROM AUTHOR]

The conversion of biomass primary pyrolysis vapors over several β-zeolites with silica-to-alumina ratios (SAR) varying from 21 to 250 was carried out in a flow microreactor to investigate the effect of number of acid sites on product speciation and deactivation of the catalyst. Experiments were conducted using a horizontal fixed bed semi-batch reactor in which up to 40 discrete 50 mg boats of biomass were pyrolyzed and the vapors upgraded over 0.5 g of the catalyst. Products were measured with a molecular beam mass spectrometer (MBMS). These studies were complemented using a tandem micropyrolyzer connected to a GCMS (py-GCMS) for speciation and quantifying the products. In the py-GCMS experiments, several 0.5 mg loads of pine were pyrolyzed sequentially and the vapors upgraded over 4 mg of catalyst. In all of these experiments, real-time measurements of the products formed were conducted as the catalyst aged and deactivated during upgrading. The results from these experiments showed that: (1) fresh catalyst for β-zeolites with lower SAR (more acid sites) produced primarily aromatic hydrocarbons and olefins with no detectable oxygen-containing species; (2) a suite of oxygenated products was observed from fresh catalysts with high SAR (few acid sites), indicating that 0.5 g of these catalyst materials did not have sufficient acid sites to deoxygenate vapors produced from pyrolysis of 50 mg of pine. This suite of oxygen containing products consisted of furans, phenol and cresols. The amount of coke deposited on each catalyst and the yield of aromatic hydrocarbons increased with the number of acid sites. However, while the catalysts were active, the biomass selectivity towards coke and hydrocarbons remained essentially constant on the catalysts of varying SAR. [ABSTRACT FROM AUTHOR]

Threeconstituents of loblolly pine (stem, residue, and bark) wereindependently pyrolyzed to produce light oil. The chemical structuresof the light oils were analyzed using GC-MS, 1H NMR, 13C NMR, and HSQC-NMR. The experimental results indicate thatlevoglucosan observed in the light oil is the major product from cellulosepyrolysis. Furanic and phenolic monomers are derived from hemicelluloseand lignin, respectively. The light oil hydrodeoxygenation reactionstudy was carried out using carbon-supported ruthenium as a catalyst.Light oils from all three constituents were independently upgradedunder 8 MPa hydrogen gas at 300 °C for 2 h. After the upgradingprocess, the aromatic rings were hydrogenated and the oxygen-containingfunctional groups were extensively removed. According to 1H NMR, the percentage of the CHnO peakarea for stem, residue, and bark decreases by 90.03%, 77.84%, and94.98%, respectively, comparedto that for the pre-HDO light oil After upgrading, the carbon yieldsare 83.31% for the bark and approximately 100% for both the stem andthe residue. The results indicate that ruthenium can hydrogenate carbonyl(CO) bonds, furan ring, and aromatic ring as well as cleavethe aliphatic C–O and C–C bonds by hydrogenolysis. However,it cannot cleave the ether and ester type bonds. [ABSTRACT FROM AUTHOR]

Highlights: [•] Pyrolysis of SW kraft lignin and pine wood were examined. [•] Various NMR and GPC were used to characterize various pyrolysis oils. [•] Fast pyrolysis improved cleavage of methoxyl, aliphatic C C and carbonyl bonds. [•] Fast pyrolysis produced more PAH from lignin. [•] Molecular weight of fast pyrolysis oils increased by ∼100%. [Copyright &y& Elsevier]

Abstract: The hydrogenation of biomass pyrolysis oils to upgraded biofuels, especially the aliphatic compounds with a low boiling range has attracted significant research attention. However, compared with the water soluble phase of pyrolysis oils, the water insoluble parts are relatively difficult to upgrade due to the complex high molecular weight aromatic structures. To solve this problem, a two step hydrogenation of water insoluble pyrolysis oil (heavy oil) produced from pyrolysis of pine wood ethanol organosolv lignin (EOL) at 600°C for 30min was examined. Ru/C was used as the catalyst and water was used as the dispersant for the heavy oil and hydrogenation products. The carbon conversion yields for the first and second step hydrogenation are 35% and 33% (overall molar% of carbon content in the heavy oil), respectively. The products of first step of hydrogenation are primarily aromatic molecules which are produced from the hydrolytic cleavage of ether bond and methoxy groups in the heavy oils. Further hydrogenation was shown to covert the insoluble heavy oils (weight average molecular weight is 265g/mol) to the aliphatic alcohols and other aliphatic components which could be used as renewable gasoline. As far as we know, this is the first reported effort to upgrade water insoluble parts of lignin pyrolysis oil to the total aliphatic components by aqueous phase hydrogenation. [Copyright &y& Elsevier]

A common goal in present and future forestry, biofuels and biomaterials practices, is the need to valorize lignocellulose processes to maximize value and optimize autonomic economy. Consequently, a key focus of modern biorefining is the on-site utilization of all residual materials generating products of the highest possible value. The LignoBoost process, recently demonstrated on the pilot-scale at Kraft pulp mills, injects CO2 into pulping liquors which results in a lower solution pH and thereby precipitates lignin. The present paper compares and evaluates the pyrolysis of pulping liquor lignins precipitated by sulfuric acid (pH 3) and the aforementioned CO2 method (pH 10.5 and 9.5). The CO2 based process yielded lignin that showed superior pyrolysis properties including low gas formation and increased bio-oil yields, close to 40%, consisting primarily of low (∼150 g mol−1) molecular weight compounds. Subsequent NMR analysis showed that the oils exhibit favorable changes in functionalities, e.g. loss of aromatic and gain in aliphatic carbon percentages as well as decrease in carboxyl and methoxyl (oxygen containing) groups. Moreover, NMR results further confirmed previously hypothesized lignin pyrolysis reactions, while at the same time showed the potential of CO2 precipitated lignin for pyrolysis and subsequent liquid biofuel production. [ABSTRACT FROM AUTHOR]

The pyrolysis of poly (ethylene terephthalate) (PET) in the presence of ZSM-5 zeolite and NiCl2 as a catalyst was studied at different temperatures under N2 atmosphere. Quantitative 13C nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FT-IR) were applied to characterize the waxy and solid residue. The carboxyl and aliphatic hydroxyl groups in the waxy residue have been greatly depleted after the use of zeolite during pyrolysis on the basis of the results of 13C NMR and FT-IR analysis. The proportion of aromatic hydroxyl groups increased by 21.82% when the mass ratio of zeolite to PET was set to 2.0/1.0. The results indicate that ZSM-5 is able to facilitate the decomposition of carboxyl, aliphatic groups, and ether bonds in the primary products produced from the pyrolysis of PET. In addition, the deoxygenation effects on the waxy products have been significantly enhanced with the addition of zeolite based on the results of NMR. [ABSTRACT FROM AUTHOR]

The pyrolytic behavior of several biomass components including cellulose, hemicellulose, lignin, and tannin, from two sources of waste biomass (i.e., pine bark and pine residues) were examined. Compared to the two aromatic-based components in the biomass, carbohydrates produced much less char but more gas. Surprisingly, tannin produced a significant amount of water-soluble products; further analysis indicated that tannin could produce a large amount of catechols. The first reported NMR chemical shift databases for tannin and hemicellulose pyrolysis oils were created to facilitate the HSQC analysis. Various C–H functional groups (>30 different C–H bonds) in the pyrolysis oils could be analyzed by employing HSQC-NMR. The results indicated that most of the aromatic C–H and aliphatic C–H bonds in the pyrolysis oils produced from pine bark and pine residues resulted from the lignin and tannin components. A preliminary study for a quantitative application of HSQC-NMR on the characterization of pyrolysis oil was also done in this study. Nevertheless, the concepts established in this work open up new methods to fully characterize the whole portion of pyrolysis oils produced from various biomass components, which can provide valuable information on the thermochemical mechanisms. [ABSTRACT FROM AUTHOR]

The large-scale flooding of Enteromorpha prolifera (EP) forms "green tide", which causes severe environmental problems. However, EP, an algal biomass, can be converted into syngas via pyrolysis. In this study, the pyrolysis mechanisms of the main compositional models of EP used to produce syngas are investigated using a combination of molecular dynamics simulations and fixed-bed experiments. Rhamnose (Rha), glucuronic acid (GlcA), aspartic acid (Asp), glutamic acid (Glu), and alanine (Ala) are used as the model compounds. The results indicate that H 2 is primarily produced by Glu (reached 24.68 vol%), followed by Asp and Ala, and CO is produced by Ala (reached 44.94 vol%), Glu, and Asp. The molecular dynamics simulation results indicate that the energy barriers for the pyrolysis of Glu and Ala to produce H 2 and CO, respectively, are the lowest. Three amino acids undergo dehydration, deamination, and decarboxylation. Moreover, the synergistic effect of the three amino acids in co-pyrolysis is reflected in the production of hydrogen groups from Asp; and the hydrogen group then attacks Glu to seize the hydrogen group on it to produce hydrogen. In addition, the H 2 content in the syngas produced by the separate pyrolysis of Rha (17.75 vol%) and GlcA (17.35 vol%) are similar and lower than those of the Rha and GlcA mixtures (19.12 vol%). The CO content in the pyrolysis gas of GlcA is higher than that of Rha. The simulation results prove that the amino acids undergo dicarboxylic and deamination reactions to produce amino acids and CO 2. Meanwhile, polysaccharide sulfate breaks glycosidic bonds, producing free radicals such as hydrogen and hydroxyl groups at 700 K. When the temperature rises to 1900 K, the products of the previous stage further break the bond, producing small-molecule gases. However, the addition of polysaccharide model compounds promotes the production of CO 2 and C O groups and inhibits the formation of CO. Co-pyrolysis cannot increase H 2 , and the synergistic effect is not significant. Moreover, Ni and SAPO-34 exhibited good catalytic activities, which could increase syngas production. A raw materials to catalyst ratio of 5:1 is a good choice because it improves the H 2 and CO contents and makes economical use of Ni. With the increase of Ni catalyst cycles, H 2 content also shows a decreasing trend, from 22.86 vol% to 16.27 vol% (third cycle). With the number of SAPO-34 cycles, the increase of CO content, from 28.66 vol% to 32.67 vol% is explained by the increase in the specific surface area of the catalyst caused by repeated use, which increases the selectivity of C2 and enhances the ability of decarbonylation. This study focuses on the syngas reaction paths and pyrolysis reactions of different EP model compounds. The pyrolysis mechanism of EP to produce syngas is determined using a combination of experiments and simulations, providing a method for the energy utilization of EP. [Display omitted] • The reaction pathways of syngas from model compounds of EP is clarified. • The synergistic effects of amino acids or saccharides exist in the hydrogen production. • The most likely amino acids to produce H2 and CO are glutamic acid and alanine. • The proportion of hydrogen gas produced by rhamnose glucuronic acid is similar. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A tandem bubbling fluidized bed/fixed bed reactor was used for CFP of bamboo sawdust. • Effect of pyrolytic/catalyst temperature on bio-oil yield and distributions was studied. • Ex-situ enhanced the formation of alkylphenols using base metal oxides as catalysts. • Mixed CaO with HZSM-5 mode facilitated the content of aromatic hydrocarbons in bio-oil. • Synergistic effect between base catalysts and HZSM-5 was revealed. Abstract Catalytic fast pyrolysis of bamboo sawdust was conducted by a tandem bubbling fluidized bed/fixed bed reactor. Effect of pyrolysis and catalyst temperatures on product yield was studied. In addition, synergistic effect of HZSM-5 and base catalysts (including CaO, MgO, and SrO) for the promotion of aromatic hydrocarbons was revealed. Experimental results illustrated that both pyrolytic and catalytic reactor temperatures played pivotal roles in the yield of bio-oil, and the optimal pyrolysis and catalytic reactor temperatures were 550 °C and 500 °C, respectively. Ex-situ catalytic trial decreased the yield of bio-oil compared to in-situ run, while it facilitated the formation of phenol and alkylphenols. Mixed catalytic upgrading modes exhibited more significant aromatization and deoxygenation activities than sequential ones. In particular, ex-situ run using CaO mixed with HZSM-5 increased the concentration of aromatic hydrocarbons to 31.34%, which was ∼11.48% higher than that derived from CaO and HZSM-5 sequentially processed mode. The dominated products in alkylphenols were cresol isomers and ethylphenols, and compared to sequential cases, mixed catalytic upgrading trials promoted the relative selectivity of phenol. Synergistic effect of base catalysts and HZSM-5 contributed to the production of monocyclic aromatic hydrocarbons, and CaO mixed with HZSM-5 mode showed the most prominent synergistic effect for the enhanced relative selectivity to xylenes and toluene. [ABSTRACT FROM AUTHOR]

[Display omitted] • The highest relative content of H 2 from MACP of waste tires over 10 wt. %Ni/HZSM-5. • The optimal reaction pathways of catalytic pyrolysis of NR, SBR, and BR for hydrogen are found. • The simulation of Ni/HZSM-5 shows the best hydrogen production capacity consistent. The mechanism for the formation of gaseous products, especially hydrogen, from the catalytic pyrolysis of waste tires by using Ni-based catalysts has been studied. The catalytic pyrolysis of the three essential components of waste tires such as natural rubber (NR), styrene-butadiene rubber (SBR), and cis -polybutadiene rubber (BR) was simulated and the pyrolysis fracture of the molecular chain was investigated. This work aims to provide a deeper understanding of the reaction thermodynamics and kinetics for the formation mechanisms of gaseous products, primarily hydrogen. Microwave-assisted catalytic pyrolysis of the waste tires over Ni-based catalysts was carried out and used to assent to the simulation results. The study revealed that with the incorporation of 10 wt% Ni/ZSM-5 catalyst, the relative content of H 2 from the catalytic pyrolysis of waste tires can be significantly improved by about 41.3 % in comparison to the same measurement done in the absence of the catalyst. Kinetic and thermodynamic simulations for the catalytic pyrolysis of waste tires were also performed and the corresponding energy barriers and Gibbs free energy changes were calculated. Accordingly, the optimal reaction path for the hydrogen production was determined by comparing and analyzing the values of those parameters. It was confirmed that the addition of Ni, ZSM-5, and Ni/ZSM-5 catalysts promote the hydrogen production reaction pathways. Among those catalysts, the simulation result verified that Ni/ZSM-5 brings a pronounced hydrogen production capacity, which was consistent with the experimental findings. [ABSTRACT FROM AUTHOR]

Pyrolysis is a promising method for converting biomass to biofuels. However, some of pyrolysis oil's physiochemical properties still limit its commercial applications. In this study, the autohydrolysis pretreatment at 175 ± 3 °C for 40 min was conducted to improve the resulting pine pyrolysis oil’s properties as a fuel. During autohydrolysis, deacetylation and decomposition of hemicellulose was observed by ion-exchange chromatography and Fourier transform infrared spectroscopy (FT-IR). In addition, the cleavage of lignin ether bonds was clearly determined by 13 C cross-polarization/magic angle spinning (CP/MAS) nuclear magnetic resonance (NMR). Phosphitylation followed by 31 P NMR analysis of the heavy oils gave detailed structural information of the hydroxyl groups; the results revealed that autohydrolysis pretreatment led to a reduction of carboxyl acids in the heavy oils generated at all three pyrolysis temperatures (400, 500, and 600 °C). The 31 P NMR analysis also revealed that autohydrolysis pretreatment led to a reduction of condensed phenolic hydroxyl groups in the heavy oils produced at 600 °C. 1 H- 13 C heteronuclear single-quantum correlation (HSQC) NMR analysis showed that at a pyrolysis temperature of 600 °C, the pretreated pine produced lower methoxy group constituents. Both 31 P and HSQC NMR results indicated that autohydrolysis pretreatment increased levoglucosan yields in the bio-oils. [ABSTRACT FROM AUTHOR]

Pyrolysis oil is a complex mixture of different chemical compounds with a wide range of molecular weights and boiling points. Due to its complexity, an efficient fractionation of the oil may be a more promising approach of producing liquid fuels and chemicals than treating the whole oil. In this work a sampling system based on fractional condensation was attached to a cyclone pyrolysis pilot plant to enable separation of the produced pyrolysis vapors into five oil fractions. The sampling system was composed of cyclonic condensers and coalescing filters arranged in series. The objective was to characterize the oil fractions produced from three different Nordic feedstocks and suggest possible applications. The oil fractions were thoroughly characterized using several analytical techniques including water content; elemental composition; heating value, and chemical compound group analysis using solvent fractionation, quantitative 13 C NMR and 1 H NMR and GC x GC − TOFMS. The results show that the oil fractions significantly differ from each other both in chemical and physical properties. The first fractions and the fraction composed of aerosols were highly viscous and contained larger energy-rich compounds of mainly lignin-derived material. The middle fraction contained medium-size compounds with relatively high concentration of water, sugars, alcohols, hydrocarbonyls and acids and finally the last fraction contained smaller molecules such as water, aldehydes, ketones and acids. However, the properties of the respective fractions seem independent on the studied feedstock types, i.e. the respective fractions produced from different feedstock are rather similar. This promotes the possibility to vary the feedstock depending on availability while retaining the oil properties. Possible applications of the five fractions vary from oil for combustion and extraction of the pyrolytic lignin in the early fractions to extraction of sugars from the early and middle fractions, and extraction of acids and aldehydes in the later fractions. [ABSTRACT FROM AUTHOR]

Ni/ZSM-5 catalyst has better catalytic effects leading to higher H 2 and hydrocarbon productions contents. [Display omitted] • The mechanism of hydrogen from CP of WTR was studied by simulations and experiments. • The Ni/ZSM-5 catalyst improves the hydrogen yield from CP of WTR. • Three catalysts reduce the energy barriers to generating the H2 pathway. • The catalysts reduce the pyrolysis temperature and improve the gas production rate. • The experimental results show that Ni/ZSM-5 has the best hydrogen production effect. Waste tires are currently disposed of through various approaches such as landfill and incineration, which not only causes environmental pollution, but also lead to the wastage of resources. As an important type of solid waste, tire rubber has a high carbon-to-hydrogen ratio, which makes it a good material for hydrogen production from pyrolysis. In this study, molecular dynamics simulations combined with experimental methods are used to explore the mechanism of hydrogen production from the catalytic pyrolysis (CP) of waste tire rubber (WTR) over Ni, ZSM-5 and Ni/ZSM-5. The simulation results show that the three catalysts potentially promote the release of hydrogen radicals from monomers and facilitate attack by H· radicals to generate hydrogen. Compared with ZSM-5 and Ni, the Ni/ZSM-5 catalyst exerts better catalytic effects, leading to higher contents of produced H 2 and hydrocarbons. In the low-temperature stage, the long chain cracks into monomer compounds, which mainly include isoprene, styrene, and 1,3-butadiene. Meanwhile, in the high-temperature stage, free radicals attack monomers to generate small molecules. The main gas products from the catalytic pyrolysis of waste tire rubber are hydrogen, methane, and ethylene. The use of all three catalysts leads to a low final catalytic pyrolysis temperature, high catalytic pyrolysis rate, and excellent catalytic effect. This work aims to provide a deeper understanding of the reaction thermodynamics and kinetics for the formation mechanisms of gaseous products, primarily hydrogen. [ABSTRACT FROM AUTHOR]

The mechanism of gas-phase products from pyrolysis of polysaccharides from Enteromorpha prolifera (PE) is researched. The sulfated polysaccharides are the most important polysaccharides in Enteromorpha prolifera. The molecular dynamics (MD) method is used to simulate the pyrolysis process of sulfated polysaccharides of Enteromorpha prolifera. Combined with the results of the pyrolysis simulations and density functional theory (DFT), rhamnose, glucuronic acid, glucose, and xylose are used as model compounds to estimate and calculate the reaction paths of hydrogen and carbon monoxide. In addition, fixed-bed pyrolysis experiments are performed with the above four monomers. The pyrolysis simulation results show that the pyrolysis process of sulfated polysaccharides is approximately divided into three stages: low-temperature, medium-temperature, and high-temperature stages. Gas-phase products are mainly produced in the high-temperature stage, and the main components of syngas are hydrogen, methane, and carbon monoxide. The simulation and experimental results show that pyrolysis of xylose is the most likely to generate hydrogen, followed by glucose, rhamnose, and glucuronic acid. The process of producing carbon monoxide from monomers goes through reactions such as dehydration, isomerization, C-C bond breakage, and decarbonylation. Moreover, the results of fixed-bed experiments indicate that when the four monomers are pyrolyzed individually, the highest proportions of hydrogen, carbon monoxide, and methane in the gas-phase products are obtained from the pyrolysis of xylose, glucuronic acid, and rhamnose. When the four monomers are mixed and then pyrolyzed, the proportion of hydrogen and carbon monoxide in the obtained gas-phase products decreases, and the proportion of carbon dioxide increases. • Mechanism of pyrolysis of polysaccharides from Enteromorpha prolifera for hydrogen production. • Mechanism of pyrolysis of polysaccharides from Enteromorpha prolifera for CO production. • Mechanism of pyrolysis of polysaccharides for syngas production was studied by a combination of experiment and simulation. [ABSTRACT FROM AUTHOR]

[Display omitted] • A microwave-heated fluidized bed system was first built. • Further improving the efficiency of the CFP of biomass and bio-oil quality. • The pyrolysis characteristics of different catalysts and biomass ratios was studied. • Hierarchical micro-mesoporous catalyst has strong regeneration ability. To improve the efficiency of the catalyst fast pyrolysis (CFP) of rice husk and the quality of bio-oil, we integrate both microwave heating and fluidized bed reactor methods and build a microwave-heated fluidized bed system. In this study, the liquid yield from the CFP of rice husk in a microwave-heated fluidized bed (55.3 wt.%) is significantly higher than that obtained from a fixed bed (47.6 wt.%). Meanwhile, the relative content of hydrocarbons from microwave assisted catalytic fast pyrolysis (MACFP) of rice husk (RH) over a hierarchical micro-mesoporous composite molecular sieve (HM-2.0 T) is 67.6 % higher than that (51.6 %) of the organic base modified HZSM-5 (HT-2.0) and HZSM-5 (40.2 %) in the microwave-heated fluidized bed system. Furthermore, we focused on the ratio of biomass to catalyst in CFP processing and discover that the increased amount of catalyst promoted the decarbonylation and decarboxylation reactions, producing more hydrocarbon compounds, however, the excessive amount of catalyst does not contribution to higher monocyclic aromatic hydrocarbon selectivity. Besides, the hierarchical micro-mesoporous composite catalyst had strong regeneration ability and reusability. The selectivity of monocyclic aromatics remained high when the regeneration times increase from 1 to 4, which provided possibilities for applications of hierarchical micro-mesoporous composite catalyst in industrial production in the future. [ABSTRACT FROM AUTHOR]