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In this study, a computational fluid dynamics mathematical model has been developed for catalytic fast pyrolysis (CFP) of biomass based on multiphase flow, transfer process, and biomass pyrolysis reactions in a bubbling fluidized bed reactor. The multiphase fluid flow, and the inter‐phase momentum and energy transfer processes are modeled with Eulerian multiphase formulas, representing the flows of gases and solids (catalyst and biomass) within the reactor. The biomass CFP reactions are described by using a two‐stage, semi‐global model. Specified secondary tar catalytic cracking process, which considers both intrinsic reaction rates and mass‐transfer process, is embedded to the developed model by user‐defined function. The model simulation results of pyrolysis product yield and distribution are compared with the experimental data with close agreement. The model is then employed to investigate the effects of structural properties of catalyst, such as specific internal area, average size of active sites, pore diameter, and tortuosity, on products yields and composition. The tar cracking process by the selected catalyst is proposed and the influences of adsorption capability of tar molecule on catalyst surface and external film mass transfer are also analyzed. The developed model can be solved with short computational time and thus it can be employed for further research and engineering designs of the catalytic pyrolysis of carbonaceous materials. [ABSTRACT FROM AUTHOR]

Catalytic fast pyrolysis (CFP) is an advanced controlled process of biomass thermal decomposition designed to produce high volumes of ready-to-use transportation biofuels or to provide improved quality bio-oil for subsequent refining or upgrading. The present work is the second part of a thorough review on the CFP of lignocellulosic biomass, emphasizing on the exploitation of agricultural residues and dedicated energy crops. Due to the increased interest on the production of high energy density transportation biofuels, such as green gasoline, green jet fuel and green Diesel, CFP has been studied intensely during the last years, using various biomass feedstocks in both in-situ and ex-situ catalytic studies. The scope of the present review is to illustrate and critically discuss the known science and the latest research outcomes of the CFP of agricultural residues and herbaceous or woody dedicated energy crops as it has been tested experimentally over the wide spectrum of available catalysts in the groups of zeolites, mesoporous catalysts, metal oxides, inorganic salts and carbon-based materials. The selection of the appropriate catalyst has a paramount effect on the features of the produced bio-oil, such as composition and properties of the obtained liquid end-product of the CFP process. This is because it influences the overall chemistry/pathways of the CFP process through the selective promotion of certain dehydration, decarboxylation, decarbonylation, hydrodeoxygenation, catalytic cracking and condensation (ketonization and Aldol condensation) reactions, and also, determines the stability and quality of the obtained bio-oil by decreasing its oxygen content and by improving its final properties for use as a fuel or for subsequent further upgrading. As it is discussed in this review, many existing catalysts are able to greatly enhance bio-oil quality by promoting the production of useful aromatic hydrocarbons, phenolics or alkanes. However, further research is needed towards the optimization of the catalytic performances in terms of activity, product selectivity and resistivity against deactivation. • The composition/quality of the obtained CFP bio-oil depends on the catalyst used. • ZSM-5 and HZSM-5 are the most effective zeolites for the production of aromatics. • Meso-MFI catalysts are promising mesoporous materials for the yield of aromatics. • CaO and MgO oxides exhibit promising CFP performance and easier regeneration. • Transportation biofuels are attainable via second-stage uprgading of CFP bio-oil. [ABSTRACT FROM AUTHOR]

The integration of Torrefaction Deoxygenation Pretreatment (TDP) and Catalytic Fast Pyrolysis (CFP) with dual catalysts was employed to improve the yield of bio-aromatics (BTX) derived from Miscanthus. Results showed that the TDP could effectively remove the oxygen content up to 38.16% at 280 °C. This resulted in a remarkable reduction of undesired oxygenate compounds in the pyrolysis oil. With ZSM-5 catalyst, the dominant components in pyrolysis oil became aromatic hydrocarbons (up to 66.29%) instead of oxygenates. The selectivity of bio-BTX increased with the increase of torrefaction temperature up to 56.63%. For the pyrolysis process, the highest yield (37.54%) and selectivity (56.63%) of bio-BTX were obtained at 600 °C. Compared with ZSM-5, the addition of CaO and MoO 3 promoted bio-BTX yield due to the enhanced deoxygenation and olefins aromatization. The integrated TDP and CFP with ZSM-5 and MoO 3 significantly improved the selectivity of bio-BTX, reaching the highest selectivity of 70.69% and a yield of 51.07%. Combining these two processes can enhance bio-aromatics yields from biomass, thus considerably improving the quality and value of the liquid product. [ABSTRACT FROM AUTHOR]

Summary: Catalytic effects in fast pyrolysis of low‐rank coal and coal tar conversion were investigated in a two‐stage fixed‐bed reactor over HZSM‐5 zeolite and Mg/HZSM‐5. Mg/HZSM‐5 caused the lower total tar yield and the higher non‐condensable gas yield but the fraction of light tar (boiling point below 360°C) increased to allow a slightly higher total yield of light tar. It also exhibited good catalytic activity and increased the species of light tar than HZSM‐5 zeolite. The light tar fraction was increased from 45 to 74.6 wt% than without catalyst (66%) at the pyrolysis temperature of 600°C. Ex‐situ catalytic fast pyrolysis over Mg/HZSM‐5 also lowered the contents of element N and S in the resulting coal tars by 29% and 15% respectively. The corresponding increase in the content of element H and molar ratio of H to C of the resulting coal tars was reported as 17% and 13% respectively. The addition of Mg into HZSM‐5 increased the ability of the catalyst for inhibiting coke deposition. [ABSTRACT FROM AUTHOR]

In this study, magnetic solid acid Fe3O4/C–SO3H600 was synthesized and applied in catalytic fast pyrolysis of cellulose for the selective production of levoglucosenone (LGO). The catalytic pyrolysis of cellulose could not only reduce the reaction-required temperature and promote the LGO production, but also could be reused for recycling in an economical and practical approach. Under the experimental conditions that the ratio of catalyst to cellulose was 1:1 and the pyrolysis temperature was 300 °C, the yield of LGO reached 20 wt%. This research also explored the mechanism of cellulosic pyrolysis to produce LGO, indicating that LGO could be produced via further dehydration of levoglucosan. [ABSTRACT FROM AUTHOR]

The perpetual market demand for polystyrene results in the gradual accumulation of polystyrene waste, placing a serious burden on the environment. This study proposed a promising method to upcycle polystyrene for styrene-derived monomers through catalytic fast pyrolysis. The metals-incorporated biochar catalysts were synthesized from heavy metals-contaminated manure waste for catalytic fast pyrolysis of polystyrene. The experimental results showed that the bimetallic biochar-derived catalyst containing Zn and Cr (Zn-Cr/C) was more conducive to the liquid production, with an extremely high yield of 88.22 wt%. Monometallic Pb-incorporated biochar catalyst (Pb/C) and bimetallic Zn-Cu co-doped on biochar (Zn-Cu/C) were more favorable for the production of pure styrene, with the mass yield of 61.26 wt% and 60.39 wt%, respectively. Additionally, the study elucidated a deep understanding of the reaction mechanisms involved in the catalytic fast pyrolysis of polystyrene. Simply put, this study introduced a new concept to convert heavy metal-contaminated animal manure into metal-incorporated biochar catalysts for catalytic conversion of polystyrene waste in pure styrene-based monomers. [Display omitted] • A new concept of upcycling polystyrene into pure monomers. • Mono-/bi-/tri-metallic Zn, Cu, Pb, Cr-containing biochar catalysts were prepared. • Bimetallic Zn-Cr/C favored the liquid production, with the high yield of 88.22 wt%. • Pb/C was more favorable for pure styrene production, reaching 61.26 wt%. • Trimetallic Zn-Cu-Pb/C had an obviously negative impact on the liquid production. [ABSTRACT FROM AUTHOR]

Catalytic fast pyrolysis of sawdust was investigated over HZSM-5 zeolites (SiO 2 /Al 2 O 3 = 25, 50 and 80) in a drop tube quartz reactor for production of green aromatics and olefins. The effects of temperature, weight hourly space velocity (WHSV), SiO 2 /Al 2 O 3 ratio and atmosphere on yield and selectivity of aromatics were investigated. The results show that almost all small organic oxygen species in initial volatiles were converted into gaseous hydrocarbons and aromatics after in situ catalysis of HZSM-5. HZSM-5 whose SiO 2 /Al 2 O 3 is 25 exhibited the best performance with the aromatics yield of 21.8% on carbon basis at 500 °C. However, HZSM-5 can act as cracking and aromatization catalyst, but not as an agent to promote hydrogenation. The ESI-MS revealed the most abundant macromolecular compounds in initial volatiles were O 1 O 27 species with 0–20 double bond equivalent (DBE) values and 5–40 carbon numbers, while the macromolecules were O 1 O 9 species with 2–12 DBE and 10–25 carbon numbers after upgrading. Furthermore, the formation of coke on catalysts was influenced by the properties of HZSM-5 and experimental conditions. Image 1 • In situ catalytic reforming of volatiles from sawdust fast pyrolysis. • Renewable olefins and aromatics were produced directly using HZSM-5. • The yield and selectivity of aromatics can be adjusted. • The macromolecular substances in bio-oils was significantly changed. [ABSTRACT FROM AUTHOR]

The catalytic activity of calcium-containing complex oxides with perovskite structure (CaTiO 3), brownmillerite structure (Ca 2 Fe 2 O 5 and Ca 2 FeAlO 5), spinel structure (CaAl 2 O 4), and pseudowollastonite structure (CaSiO 3) was compared to CaO for the upgrading of Oakwood fast pyrolysis vapors. Initial catalyst particle sizes range between 0.61 and 3.21 μm, while the BET surface area is between 0.2 and 8.7 m2/g. In contrast to CaO, the complex oxides compounds demonstrated negligible CO 2 and H 2 O chemisorption during catalytic fast pyrolysis, thereby a low deactivation of catalysts, good structural and morphological stability and thus high reusage feasibility. Due to their unique features, Ca-containing catalysts were found to promote specific reaction pathways, such as the conversion of guaiacol to 3-methyl phenol, 4-ethenyl-2-methoxyphenol to 4-ethyl-2-methoxyphenol, 1-(4-hydroxy-3,5-dimethoxyphenyl)ethanone to 3,5-dimethoxy acetophenone and long chain carboxylic acids to acetic acid through a multitude of reaction routes including demethylation/demethoxylation, hydrogenation and hydrodeoxygenation, oxidative cleavage, and dehydration reactions. CaO and Ca 2 Fe 2 O 5 promoted the alkylation reactions within the methoxy phenolics, whilst CaSiO 3 promoted hydrogenation reactions. The formation of acetic acid was promoted over Ca 2 FeAlO 5 , CaAl 2 O 4 , and CaSiO 3 , while acetone, 2-butanone, new cyclic C5 ketones were revealed over CaO. The resulting ketonic fraction was noticeably affected by the use of Ca 2 Fe 2 O 5 and CaAl 2 O 4 catalysts. [Display omitted] • Regular BZ+ in close proximity to Ca cations govern specific reaction pathways. • CaO and Ca 2 Fe 2 O 5 facilitate the alkylation within the methoxy phenolics. • Strong basic catalyst is required to form acetone, 2-butanone, new cyclic C5 ketones. • Ca 2 FeAlO 5 , CaAl 2 O 4 and CaSiO 3 promote heavy acid cracking reactions. • Low deactivation of Ca-containing complex oxides as low CO 2 and H 2 O chemisorption. [ABSTRACT FROM AUTHOR]

Catalytic fast pyrolysis of biomass/cellulose is a promising way for the production of levoglucosenone (LGO) and other value-added anhydrosugars. Herein, ammonium dihydrogen phosphate (NH 4 H 2 PO 4) modified mesoporous niobium pentoxide (P-Nb 2 O 5) was first applied to selectively produce LGO. The catalyst had a stable amorphous mesoporous structure with abundant activity species (Nb-O-Nb, Nb-O-P, P-OH, and PO 4 3-), which affected the dehydration and depolymerization reactions of cellulose to alter the competing relationship between levoglucosan (LG) and LGO. Micro-scale pyrolysis experiments demonstrated that the yield of LGO reached 19.6 wt% under the optimized condition (P loading of 50 wt%, pyrolysis temperature of 400 °C, and catalyst-to-cellulose mass ratio of 7). In lab-scale experiments, the highest yield of LGO attained 16.5 wt%, and the catalytic activity could maintain over 80% after five recycles. Overall, the P-Nb 2 O 5 has been proven to be a promising catalyst to produce LGO from cellulose. [Display omitted] • Niobium catalysts were first applied in CFP of biomass for anhydrosugar production. • P-Nb 2 O 5 exhibited excellent capability to promote LGO formation. • LG and LGO formation competed via catalyzed depolymerization and dehydration. • The maximal LGO yield reached 19.6 wt% under the P-Nb 2 O 5 at 400 °C. • The catalyst maintained a satisfactory catalytic activity after five recycles. [ABSTRACT FROM AUTHOR]

Fast pyrolysis is a potential technology for converting lignocellulosic biomass into bio-oil. Nevertheless, the high amounts of acid, oxygenated compounds, and water content diminish the energy density of the bio-oil and cause it to be unsuitable for direct usage. Catalytic fast pyrolysis (CFP) is able to improve bio-oil properties so that downstream upgrading processes can be economically feasible. Here, calcium oxide (CaO), magnesium oxide (MgO), and zinc oxide (ZnO) were employed due to their potential in enhancing bio-oil properties. The results showed that overall, all three catalysts positively impacted the empty fruit bunch fibre-derived bio-oil properties. Among the catalysts, CaO showed the most favorable effects in terms of reducing the acidity of the bio-oil and anhydrosugar. Thermal stability of bio-oils produced in the presence of CaO was studied as well. • Fixed bed catalytic fast pyrolysis of EFBF. • CaO catalyst showed the most favorable physical effects for bio-oil. • ZnO catalyst exhibited mild catalytic effects. • Aging of bio-oil caused polymerization, acidity and high water content. [ABSTRACT FROM AUTHOR]

This work aimed to investigate the effect of several metal-modified (Fe, Co, Ni, Cu, Zn) USY catalysts on the high-value aromatic production from fast pyrolysis of waste truck-tire in an infrared-heated fixed-bed reactor. The relationship between the physical and chemical properties of the catalyst and the production of light aromatic hydrocarbons was revealed based on comprehensive catalyst characterization and catalytic reaction test results, guiding the selection of the optimal modified metal and loading amount. Among all the investigated metal-modified USY catalysts, 1%Cu/USY catalyst exhibited the best aromatics production capacity, with a relative content of monoaromatics of 63.70% and a yield of specific aromatics of 42.92 mg/g, both of which were significantly greater than those obtained over the parent USY catalyst (58.73% and 27.23 mg/g). The introduced copper species provided abundant Lewis acid sites and cooperated with Brønsted acid sites to promote the cracking, dehydrogenation, and aromatization reactions to reach a specific balance, thus enhancing catalytic performance. However, when the loading amount exceeded 1 wt%, Cu species aggregate on the surface of the zeolite, leading to pore blockage and surface area reduction. High Cu loading amounts could also result in excessive acidity, which could cause excessive cracking of volatiles and lower aromatics selectivity. In addition, the 1%Cu/USY catalyst exhibited excellent reusability in the reaction/regeneration cycles. This work demonstrates the feasibility of producing light aromatics via WTT catalytic fast pyrolysis over Cu-modified USY catalyst, which provides new ideas for the chemical recovery of waste tires. [Display omitted] • Metal-modified USY was used for CFP of WTT in an infrared-heated fixed-bed reactor. • The highest relative content of monoaromatics reached 63.70% over 1%Cu/USY. • The specific aromatics yield were improved by 57.58% when using 1% Cu/USY. • 1%Cu/USY showed excellent reusability during three reaction/regeneration cycles. • Cu addition promoted the balance of cracking, dehydrogenation and aromatization. [ABSTRACT FROM AUTHOR]

Silica-alumina catalyst was prepared and used in the catalytic fast pyrolysis of durian rind in a drop-type two-stage reactor. The effects of catalytic temperature (400 °C–600 °C) and catalyst-to-durian rind ratio (1:30–3:30) were evaluated. Bio-oil yield was increased with increased catalytic temperature due to considerable dehydration process, but it was reduced with high catalyst loading due to the overcracking of organics into light gases. Silica-alumina catalyst possessed good selectivity and the products changed according to the temperature. The major components in bio-oil were hydrocarbons, furan derivatives, and aromatic compounds at 400 °C, 500 °C, and 600 °C, respectively. The hydrogen and carbon contents of bio-oil were reduced with high catalyst loading due to the overcracking of organics, and the deoxygenation process became unfavorable. The silica-alumina catalyst worked well in catalytic fast pyrolysis of durian rind, and the condition may be adjusted based on the desired products. [ABSTRACT FROM AUTHOR]

The use of catalytic fast pyrolysis (CFP) of biomass to produce high-quality bio-oils as potential substitutes for conventional fuels plays an essential role in the decarbonization of the world. In this study, continuous CFP tests of sawdust using three commercial-ready catalysts were performed. The overall objective is to screen appropriate catalysts and catalyst loading amounts for further commercialization and upgrading by evaluating the quality of the organic fraction bio-oils and clarifying the relationship between the hydrogen-to-carbon atomic effective (H/C eff) ratio and bio-oil yield. The results displayed that, owing to a cracking effect of the catalyst, all catalytic cases had higher H/C eff ratios and larger relative area percentages of hydrocarbons determined by NMR. Thermogravimetric analysis reveals that, compared to non-catalytic bio-oils, catalytic bio-oils showed more distillates in the diesel range. Increasing the catalyst-loading amount also showed the same effect. Overall, all bio-oil products from catalytic cases had H/C eff ratios higher than 0.6, indicating the production of promising oil for hydrodeoxygenation. By analyzing and fitting the data from this work and comparing with the literature, it could be concluded that its yield would decrease as the bio-oil product quality increases (the H/C eff ratios increase). [Display omitted] • Continuous CFP tests were conducted, providing insight for scaling up. • Three different commercial-ready catalysts with two WHSV values were studied. • All catalysts-induced oil products with H/C eff higher than 0.6. • SA catalyst induced the most attractive oil production at WHSV of 0.5. • A negative correlation between H/C eff ratio and bio-oil yield was verified. [ABSTRACT FROM AUTHOR]

Nickel and iron supported on thermostable cellulose-derived carbon aerogels (CAG), were used for the catalytic fast pyrolysis (CFP) of crude and torrefied Eucalyptus globulus . Pyrolysis vapors produced from torrefied biomass under non-catalytic conditions were reduced by 70% in carboxylic acids with respect to vapors originating from crude biomass, but also were richer in ketones and aromatics. In the case of CFP of both crude and torrefied E.globulus on CAG-supported iron and nickel (Fe/CAG and Ni/CAG), the metallic clusters were activated for ketonization, while Ni 0 provided additional hydrogenation sites, increasing the production of monoaromatics (c.a.18% selectivity), leading to a high acids-to-ketone (ξ A-K = 1.3) and heavy-to-light (ξ H-L = 1.0) ratios. Accordingly, Ni/CAG and Fe/CAG were more effective than HZSM-5 –a traditional cracking catalysts– for upgrading CFP vapors to light compounds. The combination of zeolite acid sites with the oxophilic Ni 0 and Fe 0 allows the deoxygenation of vapors while the ratio of polyaromatics to light aromatics (ξ PAHs ) was reduced by nearly 50%. [ABSTRACT FROM AUTHOR]

In situ catalytic fast pyrolysis can be used to produce partially upgraded bio-oils. This process, however, suffers from rapid catalyst deactivation caused by coke formation, which necessitates the use of continuous catalyst regeneration. This can be achieved by using a circulating fluidized-bed reactor. In such a reactor, one key operational variable is the catalyst-to-biomass (C/B) ratio, which influences the extent of the catalytic reactions that take place. In this study, woody biomass is pyrolyzed in a pilot-scale circulating fluidized-bed reactor system using a HZSM-5 zeolite with varying C/B ratios. The C/B ratio influences the overall product distribution, the elemental distribution, and the characteristics of the liquid products. An increase of the C/B ratio enhances the conversion of pyrolysis vapors but this does not result in a continuous improvement in bio-oil quality. The C/B ratio is, nevertheless, a factor that can be used to optimize the catalytic fast pyrolysis process. [ABSTRACT FROM AUTHOR]

[Display omitted] • Direct conversion of volatiles to aromatics over Zn@MCM-41&ZSM-5 tandem catalysis. • High aromatics yield was achieved coupling with cracking and aromatization. • Lifetime of ZSM-5 was prolonged for tandem catalysis system. • The presence of Zn@MCM-41 would pre-catalyze macromolecules into small molecules. Direct conversion of lignite into light aromatics via catalytic fast pyrolysis is a great challenge because of severe catalyst deactivation and low aromatics yield. The tandem catalysis (1Zn@MCM-41 and ZSM-5) system was employed to promote the conversion of thermally-derived volatiles of lignite into aromatics at 600 °C. The mesoporous Zn-incorporated MCM-41 (xZn@MCM-41) with different doping amount of Zn was prepared with a one-pot hydrothermal procedure. The structure and the dispersion of Zn species of 1Zn@MCM-41 were systematically studied with XRD, SEM, BET, NH 3 -TPD and so on. The presence of 1Zn@MCM-41 significantly expands the lifetime of the microporous ZSM-5. Meanwhile, the yield of aromatics, especially benzene, is also increased to some extent. The content of the long-chain hydrocarbons and the phenolic compounds are decreased significantly after being cracked by the mesoporous 1Zn@MCM-41. More small molecules are able to contact with the active sites located in the micropores of ZSM-5 with the presence of Zn@MCM-41. In addition, the ZSM-5 in the tandem catalysts system presents an excellent stability. Therefore, this meso -microporous tandem catalysis system promotes the preferential cracking of macromolecular compounds, the cracked small molecules generated from which then contact with ZSM-5 to produce aromatics. This work provides a new perspective for the gradient catalyzing lignite-derived volatiles over a tandem catalysis system. [ABSTRACT FROM AUTHOR]

Catalytic fast pyrolysis (CFP) of lignin targeting for benzene, toluene and xylenes is attractive considering lignin's chemical structures. Zeolites have been widely used for producing aromatic hydrocarbon via a well-known hydrocarbon pool mechanism from lignocellulose pyrolysis vapors because of their unique shape-selective catalytic abilities, however, the large amount of phenols existing in the product reveals the catalyst's deficiency in direct deoxygenating of phenols. Finding a catalyst with a strong deoxidization ability against various lignin pyrolysis intermediates is necessary. Here, two niobium oxide-based catalysts, niobium oxophosphate (m-NbOP) and niobium oxide (m-NbO) with uniform mesoporous structures (pore sizes of 2-5 nm), large external areas (487 m2·g−1 for m-NbOP and 244 m2·g−1 for m-NbO), and strong acidities (1.25 mmol·g−1for m-NbOP and 0.69 mmol·g−1 for m-NbO) were synthesized and used without need for hydrogen in lignin CFP at 650 °C. Compared to zeolites, both niobium oxide-based catalysts considerably increased aromatic's contents and the selectivity to benzene, toluene, and xylenes but decreased the contents of phenols to some extent, indicating the improved abilities in direct deoxygenation by aromatic C O bond cleavage of lignin. A total carbon yield of benzene, toluene and xylenes of 39.2% was achieved over m-NbOP. Niobium oxide-catalyzed deoxygenation of lignin into aromatics with a high carbon yield about 39.2% without using high pressure hydrogen. [Display omitted] • Converting lignin into aromatics by catalytic fast pyrolysis over niobium oxide. • Highly selective benzene, toluene, and xylene formed over niobium oxide catalysts. • Niobium oxide promotes lignin deoxygenation via both sp2 and sp3 C O cleavage. • It enhanced thermal processing of large lignin oligomeric molecules and fragments. [ABSTRACT FROM AUTHOR]

In situ catalytic fast pyrolysis (CFP) of biomass was conducted with base or acid catalysts in a bench-scale fluidized bed pyrolyzer. Complete mass balances were performed, allowing for quantitatively investigating the catalytic impacts on the final bio-oil composition. Acidic catalysts exhibited relatively higher activities for decomposition of sugar and pyrolytic lignin, dehydration, decarbonylation, and coke formation, as relative to base catalysts. Carbon balances revealed that a significant amount of carbon in bio-oil was transformed to coke during CFP. Due to the decrease in the bio-oil yield during CFP, significantly less energy was recovered in CFP products than in control fast pyrolysis products. CFP was also performed in micropyrolyzer and the results were compared with those in the bench-scale reactor to determine the consistency across the experimental systems. Different from the bench-scale pyrolyzer, the basic catalyst more strongly influenced the micropyrolyzer products and the discrepancies suggest a more rapid deactivation of the basic catalyst. [ABSTRACT FROM AUTHOR]

NREL's thermochemical biomass conversion research is focused on ex-situ upgrading of biomass fast-pyrolysis (FP) vapors as an efficient route to completely biogenic pyrolysis-based fuel precursors, fuels, and value-added chemicals depending on catalyst and process conditions. A near term pathway being developed uses these liquids for co-processing with petroleum feedstocks to assess biogenic carbon incorporation in hydrocarbon fuel feedstocks for potential refinery use. In this work, the impact of feedstock and catalyst on catalytic fast pyrolysis oil (CFPO) composition was determined with the oils then assessed for biogenic fuel production via FCC (fluidized catalytic cracking) co-processing. Biomass vapors were generated via fast pyrolysis with destabilizing vapor components (char, inorganics, tar aerosols) removed by hot gas filtration to produce clean vapors more responsive to catalytic upgrading. A Davison Circulating Riser (DCR), a petroleum industry standard for fluidized catalytic cracking (FCC) catalyst evaluation, was coupled to a custom pyrolyzer system designed to produce consistent-composition pyrolysis vapors as feed to the DCR. Pyrolysis vapors, derived from pure hardwood and softwood, were upgraded using commercially available modified zeolite-based catalysts to produce CFPOs. These upgraded oils were analyzed via 31P and 13C NMR spectroscopy, GCxGC-TOF/MS, carbonyl and ultimate analysis (CHNO), and simulated distillation (SIMDIS) to assess both oil chemistry and distillation behavior as they relate to catalyst and feedstock type for producing fungible hydrocarbon product liquids. These exploratory vapor-phase-upgrading results demonstrated the feasibility of producing refinery-compatible hydrocarbon fuel intermediates entirely from biomass-derived fast-pyrolysis vapors using an industry-accepted DCR system for catalytic upgrading. The FCC co-processing results demonstrated the feasibility of using CFPOs with VGO feeds in FCC refinery operations to produce biogenic carbon containing fuels. • A coupled biomass pyrolyzer/DCR system was used to produce clean, low oxygenate content catalytic fast pyrolysis (CFP) oils. • Feedstock and catalyst type impact on CFP oil composition was determined. • These CFP oils were co-processed with vacuum gas oil in the DCR to produce biogenic carbon containing fuels. • About 80% of the biogenic C became liquid fuel comprising gasoline, jet and diesel, the remainder in tailgas/coke. [ABSTRACT FROM AUTHOR]

Considering the depletion of natural resources, growing environmental problems, massive demand for petroleum, the investigation of pyrolysis of lignocellulosic biomass for liquid biofuel (bio-oil) production rich in monocyclic aromatics is getting popular. However, the crude bio-oil has many shortcomings which can be mainly attributed to its high content of oxygen in primary products. Catalytic co-pyrolysis is considered an economical method for producing considerable biofuels to replace conventional energy. The addition of co-feedings and catalysts and suitable reactors could significantly enhance the yield of bio-oil and promote the generation of monocyclic aromatics. This paper is aimed to introduce the structure of the main components of lignocellulosic biomass and reveals the pyrolysis chemistry through the behaviors that occurred during the catalytic co-pyrolysis. The recent progress and development in the field of biomass catalytic co-pyrolysis were comprehensively reviewed in terms of selection of biomass, pretreatment of raw materials, kinds of catalysts, application of co-feedings, and set of reactors, for promoting monocyclic aromatic hydrocarbon production in bio-oil and improving its quality. • Properties of lignocellulosic biomass which are conducive to high-quality pyrolysis products are introduced. • The effects of different pretreatments on biomass structure and pyrolysis products are summarized • The effective catalysts used in catalytic pyrolysis and common modification of HZSM-5 catalysts are reviewed. • The application of different kinds of co-feedings is mentioned. [ABSTRACT FROM AUTHOR]

This work aimed to investigate the feasibility of using metal-modified (Fe, Co, Ni, Cu, Zn, Ga) HZSM-5 zeolite as catalysts for high-value monocyclic aromatic hydrocarbons production via lignin catalytic pyrolysis in a two-stage fixed bed reactor. The structure-performance relationship of the catalysts was revealed based on the catalytic reaction testing results along with the acidity and textural properties obtained via systematic physicochemical characterization techniques, thus guiding the selection of the best modification metal and the optimal loading amount. As demonstrated, the 1 wt% Co modified HZSM-5 (1%Co-HZ) exhibited relatively slight coverage effect on the active sites, while increased the mesoporous surface area and average pore size of the parent HZSM-5 zeolite. Consequently, enhanced mass-transfer efficiency was attained by the 1%Co-HZ catalyst, which achieved the highest monocyclic aromatic hydrocarbons content (29.3%) among all the investigated metal-modified HZSM-5 catalysts. In addition, the Co modified sample showed better resistance to carbon deposition than that of the unmodified one. Overall, 1%Co-HZ can be used as an effective catalyst for monocyclic aromatic hydrocarbons production in lignin catalytic pyrolysis. • Direct conversion of lignin into monocyclic aromatic hydrocarbons was demonstrated. • Increased mesoporous surface area and high acid amount were attained on 1%Co-HZ. • The 1%Co-HZ catalyst achieved high production of C7-C9 aromatic hydrocarbons. [ABSTRACT FROM AUTHOR]

Catalytic fast pyrolysis (CFP) is deemed as the most promising way to convert biomass to transportation fuels or value added chemicals. Most works in literature so far have focused on the in situ CFP where the catalysts are packed or co-fed with the feedstock in the pyrolysis reactor. However, the ex situ CFP with catalysts separated from the pyrolyzer has attracted more and more attentions due to its unique advantages of individually optimizing the pyrolysis conditions and catalyst performances. This review compares the differences between the in situ and ex situ CFP operation, and summarizes the development and progress of ex situ CFP applications, including the rationale and performances of different catalysts, and the choices of suitable ex situ reactor systems. Due to the complex composition of bio-oil, no single approach was believed to be able to solve the problems completely among all those existing technologies. With the increased understanding of catalyst performances and reaction process, the recent trend toward an integration of biomass or bio-oil fractionation with subsequent thermo/biochemical conversion routes is also discussed. [ABSTRACT FROM AUTHOR]

[Display omitted] • Synthesis of mesoporous Al-SBA-15 catalyst with similar acidity to ZSM-5. • Testing of high acidity Al-SBA-15 in comparison to ZSM-5 for CFP of beech wood. • Solid acid catalysts initially followed similar reaction pathway. • Shape selectivity of ZSM-5 directed selectivity towards aromatic production. • Mesoporous Al-SBA-15 lacked shape selectivity and formed more coke. The catalytic fast pyrolysis (CFP) of biomass represents an efficient integrated process to produce deoxygenated stable liquid fuels and valuable chemical products from lignocellulosic biomass. The zeolite ZSM-5 is a widely studied catalyst for the CFP process. However, its microporous structure may limit the diffusion of high molecular weight pyrolysis intermediates to its active sites. Mesoporous aluminosilicates such as Al-SBA-15 are promising materials with larger pore sizes that can overcome these diffusional limitations. Previous comparisons between mesoporous aluminosilicates and ZSM-5 for the CFP process have neglected the disproportionately high acidity of ZSM-5. In this study, an Al-SBA-15 catalyst has been synthesised with high acidity, comparable to that of a ZSM-5 catalyst with a Si:Al ratio of 15:1. The synthesised Al-SBA-15 catalyst was characterised by N 2 physisorption, XRD and propylamine-TPD, and was compared to a ZSM-5 catalyst and a typical industrial equilibrium fluid catalytic cracking catalyst (e-FCC). All three catalysts were used at three different catalyst to biomass (C/B) ratios, to investigate the effect of varying concentrations of acid sites on the product distribution from the catalytic fast pyrolysis of beech wood. Interestingly, despite their dissimilar structural architectures, all three solid acid catalysts displayed similar reaction pathways towards the cracking of high molecular weight products such as levoglucosan and formation of intermediates including phenolics and furans. However, the selectivity towards the final catalytic products was dictated mainly by the structure of the catalysts. Despite their very similar surface area and acidity, the ZSM-5 exhibited high selectivity for the formation of desirable aromatic hydrocarbon products due to its shape-selective micropore structure, while Al-SBA-15 instead shifted the selectivity towards the formation of undesirable coke. The results highlighted the importance of catalyst shape-selectivity in the catalytic fast pyrolysis of biomass for the conversion of pyrolysis vapours into desirable products and the suppression of undesirable solid byproduct formation. [ABSTRACT FROM AUTHOR]

Abstract: Catalytic fast pyrolysis of Jatropha residue was performed over SiO2 catalysts with different pore sizes (SiO2-Q3, -Q10, -Q30, and -Q50 with pore diameters of 3, 16, 45, and 68nm, respectively) at 500°C using a pyrolyzer-gas chromatography/mass spectrometry system. SiO2-Q10, which combined weak acidity and medium porosity, was the most effective catalyst in removing oxygenated compounds such as acids, ketones, and aldehydes, which are the principal reason for the polymerization of hydrocarbons from bio-oil, and in inhibiting coke and polycyclic aromatic compound formation. SiO2-Q10 is also useful for stabilizing bio-oil and has potential for catalytic fast pyrolysis. [Copyright &y& Elsevier]

Various types of mono- and bi-metallic modified HZSM-5 catalysts such as Mo-, Fe-, Zn-, Cu-, Mo–Fe-, Mo–Zn-, and Mo–Cu-modified HZSM-5 were prepared via impregnation and were characterized by scanning electron microscope (SEM), inductively coupled plasma atomic emission spectrometry (ICP-AES), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) and pyridine adsorption infrared spectroscopy (Py-IR) analysis. Online catalytic upgrading of Arundo donax pyrolysis vapors was performed using modified zeolite catalysts in a two-stage fixed bed reactor to investigate the catalytic performance. Results showed that loading of Mo, Fe, Zn and Cu were well-dispersed, the channels and acidity of zeolites were modified. Impregnation of HZSM-5 with metals resulted in relatively lower yield of oxygenates and nitrogen-containing compounds in bio-oil as compared to the reference condition without catalyst. Moreover, the addition of metals significantly favored the catalytic selectivity towards aromatics especially monocyclic aromatic hydrocarbons (MAHs). Mo-M/HZSM-5 catalysts was the best catalyst and exhibited the optimal de-oxygenation potential (from 62.66% to 18.03%), denitrification (from 6.53% to 0.43%) and produced maximum MAHs content approximately 28.77%. Among the bimetallic modified zeolite catalysts, Mo–Zn/HZSM-5 exhibited strong catalytic effect in oxygen-free aromatization of the mixed pyrolysis vapors containing methane and propane. In the presence of Mo–Zn/HZSM-5 catalyst, the content of oxygen in bio-oil decreased from 36.07 wt% to 15.05 wt%, and the calorific value reached a maximum value of 34.12 MJ kg−1. Mo–Zn/HZSM-5 has been identified as a superior catalyst for improving the value of Arundo donax pyrolysis to make bio-oil. • Mono and bimetallic loaded HZSM-5 was used for Arundo donax CFP in two-stage system. • Aromatization performance and MAH S selectivity was obviously improved through CFP. • Mo–Zn/HZSM-5 optimally improved the pyrolysis of Arundo donax to make bio-oil. • Co-doping of Mo and Zn on HZSM-5 enhanced the aromatization of CH 4 and propane. [ABSTRACT FROM AUTHOR]

[Display omitted] • Animal bones were used as catalysts to produce nitriles. • The catalytic activity phase in bone was verified as HAP. • The effect of reaction parameters on pyrolysis products was studied and confirmed. • 18.7 % yield of nitriles with high selectivity was obtained. • A highly stable catalyst was first reported. The selectivity and stability of catalysts have always been a challenge in the field of catalytic fast pyrolysis (CFP). Herein, a series of waste animal bones collected from local market were employed as catalyst to convert biomass, with only acetonitrile and propionitrile in bio-oil, via catalytic fast pyrolysis and ammonization (CFP-A) process. Combined with characterization and control experiments of calcium-based components in bone, it was found that hydroxyapatite (HAP) was the catalytic active phase, while NaCl and KCl inorganic salts in bone inhibited the production of nitriles. Under the optimized conditions, the selectivity of acetonitrile and propionitrile from cellulose were 74.9 % and 25.1 % in bio-oil, respectively. Importantly, for the raw biomass, it still maintained high nitriles selectivity. The carbon yield of nitriles did not decrease after 10 cycles with HAP. Such a stable catalyst is first reported in the field of CFP, which is important for CFP to be economically sustainable. [ABSTRACT FROM AUTHOR]

• Partially hydrated CaO(CaO OH) is an efficient catalyst for the fast pyrolysis. • CaO OH promoted the formation of ketone based compounds and ketonisation reaction. • CaO OH promoted the conversion of furfural to cyclopentanone in a vapour phase. • CaO OH reduced significantly the methoxy-phenolic products. The impact of CaO on oakwood pyrolysis was explored by the Py-GC/MS at 500 °C. Ca(OH) 2 presents on the CaO surface, indicating its partial hydration (noted as CaO OH). CaO OH promoted the ketonisation of carboxylic acids to aliphatic ketones, furfural to cyclopentanone/2-cyclopentenone, facilitated the elimination of the methoxy-phenolic compounds. The catalyst loading did not show any significant effect on the formation of acetone, while a noticeable reduction in the phenolics was revealed. Increasing catalyst loading almost eliminated CO 2 , acids, furans, aldehydes, ether groups, whilst the fractions of alcohols, esters, sugars, and alkoxybenzene decreased noticeably. The use of partially hydrated CaO OH in the CFP can create conditions where by-products generated during the ketonisation and phenolics upgrading reactions (CO 2 , H 2 O, CO) interact through the adsorption enhance water-gas-shift reaction and through coking reactions with formation of H 2 used for hydrogenation during multistep conversion of furfural to cyclopentanone in a vapour phase. [ABSTRACT FROM AUTHOR]

• LAC was selectively produced from LDO-catalyzed cellulose fast pyrolysis. • NiSn-LDO exhibited the best capability to promote LAC formation. • The maximal LAC yield reached 9.11 wt% under the NiSn-LDO at 320 °C. As a value-added chiral chemical, 1-hydroxy-3,6-dioxobicyclo[3.2.1]oct-2-one (LAC) can be obtained via cellulose pyrolysis, but its yield is extremely low in the conventional pyrolysis process. Herein, novel nickel-tin layered double oxide (NiSn-LDO) catalysts were developed for the selective production of LAC from the in-situ catalytic fast pyrolysis (CFP) of cellulose. Several layered double oxides (LDOs) were prepared and evaluated via pyrolysis-chromatography/mass spectrometry (Py-GC/MS) tests for the in-situ CFP of cellulose. NiSn-LDO was determined as the most capable catalyst for selective LAC preparation, and further experiments were conducted to confirm the optimal condition to produce LAC over several essential factors of reaction temperature, Ni/Sn molar ratio in the NiSn-LDO catalyst, and catalyst-to-cellulose (CA-to-CL) ratio. The results demonstrated that LAC was sensitive to the reaction conditions, and its yield always exhibited the tide of first increasing followed with decreasing along with the increase of pyrolysis temperature, Ni/Sn molar ratio, and CA-to-CL ratio. The maximal LAC yield reached 9.11 wt% over the pyrolysis temperature of 320 °C using NiSn-LDO with a Ni/Sn molar ratio of 2/1 at the CA-to-CL ratio of 1/1, which was more than 5 times of that from the non-catalytic process (1.72 wt%). In addition, the NiSn-LDOs possessed much better catalytic capability to yield LAC with high selectivity than previously reported catalysts. [ABSTRACT FROM AUTHOR]

• Production of biofuels not considering the desired fuel properties is inefficient. • The 'fuel-property-first' paradigm enables production of fit-for-purpose biofuels. • Catalytic processes considering the target fuel properties should be designed. • The new paradigm will be leveraged by recent advances in computational modeling. The hazards to health and the environment associated with the transportation sector include smog, particulate matter, and greenhouse gas emissions. Conversion of lignocellulosic biomass into biofuels has the potential to provide significant amounts of infrastructure-compatible liquid transportation fuels that reduce those hazardous materials. However, the development of these technologies is inefficient, due to: (i) the lack of a priori fuel property consideration, (ii) poor shared vocabulary between process chemists and fuel engineers, and (iii) modern and future engines operating outside the range of traditional autoignition metrics such as octane or cetane numbers. In this perspective, we describe an approach where we follow a "fuel-property first" design methodology with a sequence of (i) identifying the desirable fuel properties for modern engines, (ii) defining molecules capable of delivering those properties, and (iii) designing catalysts and processes that can produce those molecules from a candidate feedstock in a specific conversion process. Computational techniques need to be leveraged to minimize expenses and experimental efforts on low-promise options. This concept is illustrated with current research information available for biomass conversion to fuels via catalytic fast pyrolysis and hydrotreating; outstanding challenges and research tools necessary for a successful outcome are presented. [ABSTRACT FROM AUTHOR]

• Deoxygenation of biomass fast pyrolysis vapors with micro-pyrolyzer and at bench scale. • Na promoted γ-Al 2 O 3 effectively converts acids via ketonization, yielding bio-oil with low TAN. • Na-Al 2 O 3 active up to high B:C ratios and stable through six reaction/regeneration cycles. • Na promotion lowered the coke combustion temperature by ~100 °C. Catalytic upgrading of pyrolysis vapors from wheat straw over Na 2 CO 3 impregnated γ-Al 2 O 3 was studied as a promising route to biofuels. The Na species were homogenously distributed on the support and created a basicity of ~0.02 mmol CO 2 /g catalyst, at 80% lower catalyst acidity. Analytical pyrolysis using a micro-pyrolyzer showed that Na-Al 2 O 3 particularly decreased the yield of acids via ketonization, which was confirmed by feeding carboxylic acid model compounds. The presence of Na decreased the coke yield and catalyzed the coke combustion, decreasing the combustion temperature by ~100 °C. Subsequently, 100 g Na-Al 2 O 3 catalyst was tested in an ablative bench scale fast pyrolysis unit where ~5 kg of wheat straw was pyrolyzed and the vapors passed the catalytic reactor during six reaction/regeneration cycles. In agreement with the micro-pyrolyzer results, Na-Al 2 O 3 was highly effective in reducing the acidity of the bio-oils. Total acid numbers (TAN) as low as ~1–4 mg KOH/g could be maintained up to high B:C ratios of ~13. For a given TAN, this allowed operating to higher B:C ratios and provided higher oil yields compared to using acidic catalysts such as γ-Al 2 O 3 and HZSM-5 zeolite for vapor treatment. At bio-oil energy recoveries of ~60–70% relative to raw bio-oil, the deoxygenation was comparable to the acidic catalysts. Operation to higher B:C ratios allowed increasing the energy recovery to ~85% relative to the non-treated bio-oil while still obtaining a good deoxygenation performance of ~60%. Despite the hydrothermal conditions during reaction and oxidative regeneration, the activity of Na-Al 2 O 3 was regained by coke combustion, the Na remained well dispersed on the support, and the catalyst maintained its capacity for CO 2 adsorption at 500 °C after six reaction/regeneration cycles. [ABSTRACT FROM AUTHOR]

Analytical pyrolysis-comprehensive two-dimensional gas chromatography/mass spectrometry (Py-GC × GC/MS) was employed for the on-line analysis of cellulose via catalytic pyrolysis with different catalysts and catalytic temperatures to study the products and aromatic hydrocarbons selectivity. The catalysts were subjected to characterization methods, including XRD, TEM, NH 3 -TPD, to investigate the effects of the physicochemical properties of the catalyst on the product distribution. Results showed that the Ce 0.8 Zr 0.2-x Al x O 2 could significantly promote the formation of aromatic hydrocarbons under 400–550 °C. A lower catalytic temperature (≤350 °C) favored the formation of furan compounds, and a higher catalytic temperature (≥450 °C) supported the formation of aromatic hydrocarbons. The relative peak area of the aromatics prepared by using the Ce 0.8 Zr 0.15 Al 0.05 O 2 catalyst was the highest being 85.24% at 550 °C. Moreover, the selectivity of the single-ring aromatics, such as benzene, toluene and xylene, were significantly affected by the presence of the Ce 0.8 Zr 0.2-x Al x O 2 catalysts. The higher total acidity of Ce 0.8 Zr 0.15 Al 0.05 O 2 favored the formation of benzene and toluene. Additionally, the Ce 0.8 Zr 0.15 Al 0.05 O 2 catalyst had a great thermal stability. The catalyst recycling tests showed that the Ce 0.8 Zr 0.15 Al 0.05 O 2 catalyst can be reused five times to produce aromatic-rich bio-oil via catalytic fast pyrolysis. Unlabelled Image • Py-GC×GC/MS was employed to achieve catalytic fast pyrolysis of cellulose and on-line analysis of catalytic products. • Ce 0.8 Zr 0.2-x Al x O 2 catalysts were found to be an effective catalyst. • The highest relative peak area (87.24%) of aromatics was achieved from cellulose over Ce 0.8 Zr 0.15 Al 0.05 O 2 at 550°C. • Ce 0.8 Zr 0.15 Al 0.05 O 2 catalyst can be reused five times to produce aromatic-rich bio-oil via catalytic fast pyrolysis. • Reduction of coke formation in the CFP of cellulose using Ce 0.8 Zr 0.2-x Al x O 2 catalysts. [ABSTRACT FROM AUTHOR]

• MCM-41/ZSM-5 composites were successfully prepared via aerosol-based method. • Prepared composites were used for CFP of miscanthus × gigantus. • ZSM-5 in the composite was fully accessible during CFP of biomass. • MCM-41 acts as a sacrificial layer for coke deposition extending the lifetime of ZSM-5. ZSM-5 is a promising catalyst for the catalytic fast pyrolysis (CFP) of biomass due to its high selectivity to light hydrocarbons. However, rapid deactivation of catalyst has been a major challenge towards the commercialization of CFP. The objective of our study is to evaluate the performance of MCM-41/ZSM-5 composites during the CFP of biomass. Here, for the first time, we report the synthesis of a unique MCM-41/ZSM-5 composite via a one-step, facile aerosol-based method. The composition of ZSM-5 in the composites was varied and the prepared composites were used as catalysts for the in-situ and ex-situ CFP of miscanthus × gigantus. The prepared composites were characterized by N 2 adsorption-desorption, XRD, SEM, TEM and DRIFTS-pyridine adsorption. The results of CFP experiments demonstrated that ZSM-5 in the composites was fully accessible. Most importantly, MCM-41 acted as a sacrificial layer for coke deposition and decreased the deactivation rate of the ZSM-5. [ABSTRACT FROM AUTHOR]

The treatment of biomass-derived fast pyrolysis vapors with solid acid catalysts (in particular HZSM-5 zeolite) improves the quality of liquid bio-oils. However, due to the highly reactive nature of the oxygenates, the catalysts deactivate rapidly due to coking. Within this study, the deactivation and product yields using steam-treated phosphorus-modified HZSM-5/γ-Al2O3 and bare γ-Al2O3 was studied with analytical Py-GC. While at a fixed catalyst temperature of 450 °C, a rapid breakthrough of oxygenates was observed with increased biomass feeding, this breakthrough was delayed and slower at higher catalyst temperatures (600 °C). Nevertheless, at all (constant) temperatures, there was a continuous decrease in the yield of oxygen-free hydrocarbons with increased biomass feeding. Raising the reaction temperature during the vapor treatment could successfully compensate for the loss in activity and allowed a more stable production of oxygen-free hydrocarbons. Since more biomass could be fed over the same amount of catalyst while maintaining good deoxygenation performance, this strategy reduces the frequency of regeneration in parallel fixed bed applications and provides a more stable product yield. The approach appears particularly interesting for catalysts that are robust under hydrothermal conditions and warrants further investigations at larger scales for the collection and analysis of liquid bio-oil. [ABSTRACT FROM AUTHOR]