Catalytic Fast Pyrolysis Of Biomass Research Articles

Intrinsic promotion mechanism of calcium oxide on ketone production during catalytic fast pyrolysis of biomass via experiment and density functional theory simulation

CaO modified with acetic acid solution or sodium hydroxide (H-CaO/OH-CaO) was used to explore the relationship between the physical and chemical properties of CaO and the components of bio-oil during the pyrolysis of rice straw (RS) and model compounds via experiment and density functional theory(DFT) simulation. The results showed that the modification changed the properties of CaO, and thus the catalytic performance on production of bio-oil components. H-CaO with the larger number of strong basic sites (1.10 ∼ 2 times than commercial CaO) and the longer Ca-O bond length showed the better selectivity and performance on formation of ketones (the maximum relative content in bio-oil reached 43 %). The conversion pathway of cellulose/hemicellulose was changed by H-CaO, which promoted the formation of ketones. The easier combining of H-CaO with the pyrolysis primary products due to the longer Ca-O bond was the key to its better performance.

Catalytic Fast Pyrolysis of Biomass over Hierarchical Zeolites: Comparison of Mordenite, Beta, and ZSM-5

Catalytic Fast Pyrolysis of Biomass over Hierarchical Zeolites: Comparison of Mordenite, Beta, and ZSM-5

Benzene, Toluene, and Xylene (BTX) Production from Catalytic Fast Pyrolysis of Biomass: A Review

Benzene, Toluene, and Xylene (BTX) Production from Catalytic Fast Pyrolysis of Biomass: A Review

Hollow ZSM-5 encapsulated with single Ga-atoms for the catalytic fast pyrolysis of biomass waste

The development of efficient metal-zeolite bifunctional catalysts for catalytic fast pyrolysis (CFP) of biomass waste is highly desirable for bioenergy and renewable biofuel production. However, conventional metal-loaded zeolites often suffer from metal sintering during pyrolysis and are thus inactivated. In this study, single-site Ga-functionalized hollow ZSM-5 (GaOx@HS-Z5) was synthesized via an impregnation-dissolution-recrystallization strategy without H2 reduction. The Ga atom was coordinated to four oxygen atoms in HS-Z5 frameworks. Benefitting from the highly dispersed single-Ga atoms and hollow zeolite framework, 3GaOx@HS-Z5 performed the best in producing hydrocarbon-rich bio-oil compared to impregnated 3GaOx/HS-Z5 and H2-reduced 3Ga@HS-Z5 in the maize straw CFP. In particular, 3GaOx@HS-Z5 delivered the highest bio-oil yield (23.6 wt%) and hydrocarbon selectivity (49.4 area%). 3GaOx@HS-Z5 also retained its structural integrity and catalytic activity after five pyrolysis-regeneration cycles, demonstrating its advantage in practical biomass CFP. The elimination of H2 reduction during the synthesis of catalyst provides an additional advantage for simplifying the CFP process and reducing operating costs. The retained Ga micro-environment and anti-sintering properties were unique for 3GaOx@HS-Z5, as severe metal sintering occurred during pyrolysis for other metals (e.g., NiOx, ZnOx, FeOx, and CoOx) that encapsulated HS-Z5.

Production of bio-oils from the catalytic pyrolysis of neem sawdust: Comparative study of versatile zeolite parameters

Catalytic fast pyrolysis (CFP) is promising in converting biomass into renewable bio-oils, wherein zeolites play a critical role in bio-oil upgrading. Although it is widely known that zeolite properties (e.g., morphology, acidity, metal modification) determine bio-oil quality, studies on their uniformly comparative effect are limited and hinders a precise design of efficient zeolite catalyst for biomass CFP. Herein, the CFP of neem sawdust was catalyzed by fourteen ZSM-5 zeolites with different structural parameters. The separate impacts of zeolite morphologies (0.2, 0.5, 1, 3 μm), acidity (Si/Al = 25, 50, 100, 200), loaded metal types (Ni, Zn, Co, Ce), and metal loadings (1, 2, 5, 8 wt%) on bio-oil production were initially studied in detail. Then, their relative contributions in regulating bio-oil yield and hydrocarbon selectivity were compared. Results showed that nanosized ZSM-5 with a higher Si/Al ratio improved bio-oil yield, while metal modification had a greater impact on hydrocarbon selectivity. The nanosized 2NiOx/ZSM-5 with a Si/Al ratio of 50 and a NiOx loading of 2 wt% was superior in producing a maximized bio-oil yield and a satisfactory hydrocarbon selectivity. To shed light on future zeolite catalyst design, a pyrolysis mechanism was proposed for neem sawdust over ZSM-5 with varied parameters.

Aromatics production from segmented co-pyrolysis of poplar sawdust and high-density polyethylene: Enhancing the synergistic effects

Catalytic co-pyrolysis of biomass and plastic waste is a promising approach for producing renewable biofuels and value-added chemicals. However, because of their different pyrolysis behaviors, the synergy between biomass and plastic is limited, and low-yield aromatics are produced. Herein, a modified segmented catalytic co-pyrolysis technology was proposed, and the effects of pyrolysis parameters were studied in detail to enhance the synergistic effect between feedstocks. For the biomass section (segment 1), catalytic fast pyrolysis (CFP) of poplar sawdust was conducted, and results showed that employing 15 wt% MgCl2 at 500 °C facilitated the production of furans. For the plastic section (segment 2), CFP of high-density polyethylene (HDPE) were performed. It was showed that instead of Y and beta zeolites, the utilization of ZSM-5 as a pyrolysis catalyst with a loading of ZSM-5/HDPE = 1.0, and a temperature of 600 °C was beneficial for the production of short-chain olefins. For the segmented co-pyrolysis of poplar sawdust and HDPE (segment 1 + segment 2), the biomass-to-plastic ratio was crucial in aromatics production. A ratio of 1:1 was found to be most effective in producing MAHs (54.8 area%), which was ∼3.9 or 1.6 times that for the separate CFP of biomass or HDPE. This was also consistent with its higher enhancement factor, confirming that the synergy between poplar sawdust and HDPE was dramatically enhanced. Finally, a segmented catalytic co-pyrolysis reaction pathway was proposed.

Advancements and challenges in the production of low-carbon fuels via catalytic fast pyrolysis of biomass through refinery integration and co-product generation

Creating pathways to renewable fuels, chemicals, and materials through improved catalyst formulations and integrated process development.

Prediction of sustainable aviation fuel properties for liquid hydrocarbons from hydrotreating biomass catalytic fast pyrolysis derived organic intermediates

Prediction of fuel properties of the jet boiling range product after hydrotreating biomass-derived catalytic fast pyrolysis oil enables research, development, and adoption of sustainable aviation fuels (SAF) via pyrolytic conversion.

Perspectives of Biomass Catalytic Fast Pyrolysis for Co-refining: Review and Correlation of Literature Data from Continuously Operated Setups

Perspectives of Biomass Catalytic Fast Pyrolysis for Co-refining: Review and Correlation of Literature Data from Continuously Operated Setups

Sustainable Aromatic Production from Catalytic Fast Pyrolysis of 2-Methylfuran over Metal-Modified ZSM-5

The catalytic fast pyrolysis (CFP) of bio-derived furans offers a promising approach for sustainable aromatic production. ZSM-5 modified by different metal species (Zn, Mo, Fe, and Ga) was employed in the CFP of bio-derived furans for enhancing aromatic production. The effects of metal species, metal loadings, and the weight hourly space velocity (WHSV) on the product distributions from the CFP of 2-methylfuran (MF) were systemically investigated. It is found that the introduction of Zn, Mo, Fe, and Ga on ZSM-5 significantly increases the MF conversion and aromatic yields. The maximum MF conversions of 75.49 and 69.03% are obtained, respectively, by Fe-ZSM-5 and Ga-ZSM-5, which boost the aromatic yield by 34.5 and 42.7% compared to ZSM-5. The optimal loading of Fe on ZSM-5 is 2%. Additionally, the highest aromatic yield of 40.03% is achieved by 2%Fe-ZSM-5 at a WHSV of 2 h−1. The catalyst characterization demonstrates that the synergistic effect of Brønsted and Lewis acid sites in Fe-ZSM-5 is responsible for achieving the efficient aromatization of MF. The key to designing improved zeolite catalysts for MF aromatization is the introduction of large numbers of new Lewis acid sites without a significant loss of Brønsted acid sites in ZSM-5. These findings can provide guidelines for the rational design of better zeolite catalysts used in the CFP of biomass and its derived furans.

Synergistic enhancement of bio-oil quality through hydrochloric or acetic acid-washing pretreatment and catalytic fast pyrolysis of biomass

Peanut shells were used as raw materials, and the synergistic effects of various acid pretreatments and catalytic pyrolysis for biomass were comprehensively studied. The results showed that the oil yield of 0.5 mol/L hydrochloric acid treatment was 44.75 wt%, and that of 0.5 mol/L acetic acid treatment was 43.40 wt%. The solid products decreased apparently after pretreatment. Acid-washing pretreatment and the subsequent catalytic pyrolysis of the pretreated biomass promoted the yield of aromatic in bio-oil. The yield of bio-oil gradually decreased while the gas yield increased with the increase of catalytic pyrolysis temperature. Ketones and anhydrosugars were also reduced in the bio-oil, while aromatics increased significantly, reaching the highest value of 19.62 wt% (0.5 mol/L hydrochloric acid treatment) and 19.30 wt% (0.5 mol/L acetic acid treatment) respectively at 600 ℃. Synergy effect facilitated the conversion of pyrolytic intermediates to gas and aromatics. Besides, the possible formation mechanism of bio-oil under different pyrolysis conditions is proposed. The study indicates the optimized combination could effectively improve the quality of bio-oil.

The mechanism for catalytic fast pyrolysis of levoglucosan, furfural and furan over HZSM-5: An experimental and theoretical investigation

• The mechanism of levoglucosan conversion over HZSM-5 was investigated. • Catalytic fast pyrolysis of levoglucosan, furfural and furan were carried out. • Experiments and DFT modelling were employed to elucidate the reaction mechanism. • The mechanism of direct catalytic route from levoglucosan to furan was revealed. In this work, we have investigated the complicated reaction network of biomass catalytic fast pyrolysis, particularly the decomposition of the key cellulose pyrolysis intermediate, levoglucosan. Fast pyrolysis of levoglucosan using a Py-GC-MS-FID system in the presence of HZSM-5 suggested that furan and furfural are key intermediates to aromatic hydrocarbons. This was followed by theoretical modelling adopting density functional theory (DFT) to unravel the details of the catalytic reaction mechanism from levoglucosan to furan. Our investigations revealed for the first time a direct route from levoglucosan to furan without furfural as an intermediate, with the highest energy barrier along the most favourable pathway to be 2.15 eV. Combined with previously reported mechanisms in the literature, we provide here a detailed reaction network for the conversion of cellulose-derived intermediates to aromatic hydrocarbons.

Product regulation and catalyst deactivation during ex-situ catalytic fast pyrolysis of biomass over Nickel-Molybdenum bimetallic modified micro-mesoporous zeolites and clays

Ni-Mo bimetallic modified micro-mesoporous zeolite catalysts were prepared and employed in the process of ex-situ catalytic fast pyrolysis (CFP) of poplar to produce liquid fuel. Clay catalysts were incorporated to further improve the products quality. The mass yield of monocyclic aromatic hydrocarbons (MAHs) increased under the catalysis of composite catalysts AZM and NiMo/AZM. HAP&Zeolite dual catalyst system reduced coke yield of NiMo/AZM to 5.01 wt%. Through real-time monitoring of gas products, the catalytic performance of zeolites began to decrease after the ratio of biomass and catalyst was more than 1. A series of characterization results futher demonstrated that AZM and NiMo/AZM possessed more stable catalytic ability and higher catalytic activity during the whole CFP process. N2 adsorption–desorption measurement and Raman characterization illustrated the formation and structure of coke, catalyst deactivation and the protective mechanism of mesopores on micropores.

Model quantification of the effect of coproducts and refinery co-hydrotreating on the economics and greenhouse gas emissions of a conceptual biomass catalytic fast pyrolysis process

In this work we present model results for a scaled-up conceptual process informed by bench scale biomass catalytic fast pyrolysis (CFP) and hydrotreating experimental data. This process uses a Pt/TiO2 catalyst during CFP, which produces a partially deoxygenated organic biocrude intermediate that is then hydroprocessed to a hydrocarbon fuel blendstock; the catalyst also enables high yields of acetone and methyl-ethyl-ketone (MEK) coproducts. Two options for hydroprocessing were modeled: (A) co-hydrotreating at a petroleum refinery using hydrogen sourced from steam reforming of natural gas and (B) standalone hydrotreating at a biorefinery using hydrogen sourced from CFP off gases. The results revealed that Case A was economically advantageous with a modeled minimum fuel selling price (MFSP) of $2.83/GGE or gallon gasoline equivalent (in 2016 US dollars), while the additional cost of standalone hydrotreating facilities in Case B increased the MFSP to $3.13/GGE. Conversely, greenhouse gas (GHG) emissions were lower for Case B (3.9 g CO2e/MJ) compared to Case A (21.5 g CO2e/MJ) due to the use of biogenic (Case B) and fossil-derived (Case A) hydrogen. In a third option (Case C), the requirements for separation and purification of acetone and MEK were removed from the refinery co-processing scenario (Case A) to evaluate the impacts of this process simplification. Elimination of these coproducts increased the MFSP to $3.21/GGE and GHG emissions to 35 g CO2e/MJ. These comparisons based on our detailed conceptual models provide economic and sustainability guidance regarding processing choices for future biorefineries. While refinery coprocessing using existing equipment and the production of relatively valuable coproducts can benefit the economics, the hydrogen-source and biogenic coproducts can have significant impacts on the sustainability of the process, and feasibility to use CFP off-gases or other renewable sources for hydrogen production can help lower GHG emissions.

Accelerating catalyst development for biofuel production through multiscale catalytic fast pyrolysis of biomass over Mo2C

Advanced catalytic materials play an enabling role in producing renewable fuels and chemicals from biomass, thereby helping meet the global climate-change goals set forth by the Intergovernmental Panel on Climate Change. Herein, we present a multiscale approach to accelerate the catalyst-process development cycle for catalytic fast pyrolysis (CFP) of biomass over Mo 2 C. Mo 2 C has been shown to possess co-localized acidic and metallic sites and exhibit high activity for deoxygenation of biomass pyrolysis model compounds. However, critical knowledge gaps remain regarding the effectiveness of this catalyst for CFP of whole biomass. We address these knowledge gaps and demonstrate that Mo 2 C is effective at deoxygenating biomass-pyrolysis products in the presence of H 2 but that it undergoes rapid selective and non-selective deactivation. The knowledge gaps addressed from this integrated study, targeting appropriate experiments across scales and feed types, enabled identification of critical modifications for advancing the CFP catalyst-process development cycle. • A multiscale evaluation of Mo 2 C for biomass catalytic fast pyrolysis is performed • Mo 2 C exhibits both selective and non-selective deactivation with whole biomass • Process and catalyst modifications are proposed for reducing deactivation • Model compound studies are essential but insufficient at predicting performance Catalytic fast pyrolysis (CFP) of biomass is an attractive process for producing bio-oils that can be further refined into fuels and chemicals, thus helping to reduce greenhouse-gas emissions. To meet the emissions reduction goals set forth by the Intergovernmental Panel on Climate Change, catalysts and processes for generating renewable products need to be rapidly designed and developed, calling for an accelerated catalyst-process development timeline. However, in the case of CFP, biomass pyrolysis produces a complex stream involving hundreds of molecules with multifunctional groups, steam, and metal impurities, which makes catalyst design challenging. This integrated study on biomass CFP over a promising multifunctional catalyst, Mo 2 C, addresses knowledge gaps critical to accelerating development of this catalyst and process. The intended outcome is to share lessons learned toward accelerating catalyst-process development cycles for systems with similar complex reaction chemistries. Accelerating the catalyst-process development cycle for complex chemistries, especially biomass processing, requires multiscale studies spanning model compound experiments to integrated, bench-scale tests with realistic feedstocks.

Insight into the synergistic reaction mechanism of biomass pseudo components and low-density polyethylene for the production of light aromatics through co-catalytic fast pyrolysis over hierarchical HZSM-5

Co-feeding of waste plastics during biomass catalytic fast pyrolysis can improve remarkably the yield of aromatic hydrocarbons. In this work, the simulated biomass by using its model components of cellulose, xylan, and lignin at different proportions was Co-CFP with LDPE to investigate the synergistic reaction mechanism between biomass and low-density polyethylene (LDPE) over hierarchical HZSM-5. Results showed that biomass and its model components were oxygen-enriched feedstock, while LDPE was the hydrogen-enriched feedstock with H/Ceff over 2. The synergistic effect between biomass model components and LDPE was ordered as cellulose and LDPE > xylan and LDPE > lignin and LDPE. Because pyrolysis of cellulose produced higher yield of furans than that of xylan and lignin which acted as the key synergistic compounds in Diels-Alder reaction to form light aromatics. The transfer of hydrogen free radical from the LDPE-derived hydrocarbons to the biomass-derived oxygenates promoted the deoxygenation reaction of oxygenates in hierarchical HZSM-5. Diels-Alder reaction between furans and olefins was the key synergistic reaction which highly improved the yield of hydrocarbon aromatics. In general, the difference of the pyrolysis oxygenated intermediate among the biomass pseudo components resulted in different yields of light aromatics, where cellulose presented highest extent of synergistic reaction to LDPE.

Effect of low-temperature hydrothermal treatment of HZSM-5 extrudates on the production of deeply-deoxygenated bio-oil via ex-situ catalytic fast pyrolysis of biomass

Catalytic fast pyrolysis (CFP) of biomass has high potential for producing deoxygenated bio-oil in one single process. HZSM-5 is a widely used catalyst for this purpose and various parameters have already been extensively investigated on this catalytic material. Limited studies were performed on the effect of low-temperature hydrothermal treatment of the catalyst with none being applied in ex-situ CFP in a lab-scale pyrolysis unit. The current paper therefore reports the investigation of HZSM-5 characteristics and activities when hydrothermally treated by steam at 550 °C for 5 h. The treatment modified the catalyst in a positive way that can increase 30% of the non-aqueous catalytic bio-oil yield. A maximum organic liquid yield of 11.4 wt% was achieved with 6.7 wt% being heavy fraction and 4.7 wt% being light fraction. These heavy and light bio-oils had very low oxygen contents of 4.3 and 1.6 wt%, respectively. This is equivalent to 93% oxygen removal compared to its corresponding non-catalytic bio-oil. Based on the elemental, FTIR, and GC/MS analyses, the hydrothermal treatment slightly increased the bio-oil oxygen content. Characterization of the catalysts reveal irreversible catalyst deactivation by dealumination. The severity of the deactivation increased continuously with higher amount of biomass being fed to the process. However, the catalyst deoxygenation ability was still acceptable for producing partially-deoxygenated bio-oil even after applying the biomass-to-catalyst ratio of 20.5.

Enhancement of BTX production via catalytic fast pyrolysis of almond shell, olive pomace with polyvinyl chloride mixtures

This work addresses enhanced benzene, toluene and xylene (BTX) production by catalytic fast co-pyrolysis from agroindustrial biomass blended with PVC and the use of prepared NaZSM-5 and HZSM-5. Results from catalytic fast pyrolysis of biomass indicates that oxygen-containing compounds decreased whereas aromatics increased. The catalytic effect of mineral content altered the co-pyrolysis intermediates by increasing the formation of mono-aromatics while reducing poly-aromatic hydrocarbons. Furthermore, the addition of PVC strongly influenced thermal decomposition of agricultural waste biomass, where BTX yields were enhanced up to 26.6% and 25.1% for 1:2 OP/PVC-HZ and 1:2 AS/PVC-HZ, respectively. Yields of toluene and xylene peaked at 19% and 10.5% hydrocarbon yields with 1:2 OP/PVC-HZ blend. Additionally, from the pyrolytic gas, CH4 yields increased while the CO2 yield fell due to oxygen removal by decarboxylation. These findings could provide a great insight into the olive pomace and almond shell valorization through an inexpensive and straightforward easy process.

Dual-catalyst catalytic pyrolysis of poplar sawdust: A systematic study on first-layered catalysts

• A systematic study was conducted on the dual-catalyst CFP of poplar sawdust. • Totally 18 catalysts belonging to three types were tested as first-layered catalysts. • Effects of the 18 first-layered catalysts on the bio-oil production were evaluated. • Synergistic effects between the dual-layered catalysts were studied and compared. • Porous materials + ZSM-5 provided the highest bio-oil yield and quality. Dual-catalyst catalytic fast pyrolysis (CFP) technology is effective in converting biomass waste into hydrocarbon-rich bio-oils. However, systematic studies on dual-catalyst biomass CFP are limited, especially with respect to the best-performed dual catalyst design. In this context, dual-catalyst CFP of poplar sawdust was conducted with 18 in-situ first-layered catalysts, including 6 inorganic salts (NaCl, KCl, MgCl 2 , ZnCl 2 , K 3 PO 4 , and K 2 HPO 4 ), 7 metal oxides (SiO 2 , Al 2 O 3 , CaO, MgO, ZnO, Fe 2 O 3 , and CuO), and 5 porous materials (SBA-15, MCM-41, Y zeolite, Beta zeolite, and SAPO-34), while the ZSM-5 zeolite was fixed as an ex-situ second-layered catalyst. The effects of the 18 first-layered catalysts on bio-oil production were investigated and compared. Applying the porous materials as the first-layered catalysts increased the bio-oil yields compared to the inorganic salts and metal oxides. In particular, mesoporous SBA-15 combined with ZSM-5 led to the highest bio-oil yield of 19.4 wt% and a satisfactory hydrocarbon selectivity of 30.5 area%. The synergistic effects of the dual-layered catalysts were also studied. The first-layered catalysts cracked the primary biomass volatiles into smaller oxygenates, while the second-layered ZSM-5 deoxidized these molecules to hydrocarbons. In addition, the porous materials exhibited better synergy with ZSM-5 by simultaneously deoxygenating all the oxygenate types. The dual catalysts configured by Beta + ZSM-5 converted the most oxygenates into hydrocarbons, and the hydrocarbon selectivity (41.4 area%) was twice that in the blank experiment ( Thermal/ZSM-5 ). Therefore, combining the porous materials and ZSM-5 delivers a promising catalyst for dual-catalyst biomass CFP.

Computational fluid dynamics modeling of biomass catalytic fast pyrolysis in bubbling fluidized reactor: Effects of catalyst parameters on process performance

AbstractIn 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.