Catalytic Upgrading Of Pyrolysis Vapors Research Articles

Cooperative production of monophenolic chemicals and carbon adsorption materials from cascade pyrolysis of acid hydrolysis lignin

A novel cascade pyrolysis upgrading process for acid hydrolysis lignin (AHL), consisting of pyrolysis, catalytic upgrading of pyrolysis vapors, and pyrolysis char, was developed to improve the yield of value-added products (monophenolic chemicals and carbon materials). Pyrolysis of AHL at 450 °C and subsequent catalytic upgrading of pyrolysis vapors over Ni/H-ZSM-5 boosted the concentration of monophenolic chemicals in pyrolysis liquids by 58%. The carbon material prepared from pyrolysis char using KOH as activating agent exhibited a large specific surface area of 2902.5 m2/g and a large total pore volume of 1.45 cm3/g, thus affording good adsorption capacity for methylene blue (824.87 mg/g) and iodine (2333.17 mg/g). Moreover, the cascade pyrolysis upgrading of AHL achieved a yield of 68.52% desired products, which was much higher than the reported results (single production of monophenols and pyrolysis char). In summary, this work provides a potential reference for efficient utilization of lignin in large-scale applications.

Catalytic Upgrading of Pyrolysis Vapors from Scenedesmus sp. Microalgae towards Renewable Hydrocarbons using a Low-Cost Zeolite Synthesized from Rice Husk Ash and Diatomite Residue

Catalytic Upgrading of Pyrolysis Vapors from Scenedesmus sp. Microalgae towards Renewable Hydrocarbons using a Low-Cost Zeolite Synthesized from Rice Husk Ash and Diatomite Residue

Exploring a Low-Cost Valorization Route for Amazonian Cocoa Pod Husks through Thermochemical and Catalytic Upgrading of Pyrolysis Vapors.

Ecuador as an international leader in the production of cocoa beans produced more than 300 000 tons in 2021; hence, the management and valorization of the 2 MM tons of waste generated annually by this industry have a strategic and socioeconomic value. Consequently, appropriate technologies to avoid environmental problems and promote sustainable development and the bioeconomy, especially considering that this is a megadiverse country, are of the utmost relevance. For this reason, we explored a low-cost pyrolysis route for valorizing cocoa pod husks from Ecuador's Amazonian region, aiming at producing pyrolysis liquids (bio-oil), biochar, and gas as an alternative chemical source from cocoa residues in the absence of hydrogen. Downstream catalytic processing of hot pyrolysis vapors using Mo- and/or Ni-based catalysts and standalone γ-Al2O3 was applied for obtaining upgraded bio-oils in a laboratory-scale fixed bed reactor, at 500 °C in a N2 atmosphere. As a result, bimetallic catalysts increased the bio-oil aqueous phase yield by 6.6%, at the expense of the organic phase due to cracking reactions according to nuclear magnetic resonance (NMR) and gas chromatography-mass spectrometry (GC-MS) results. Overall product yield remained constant, in comparison to pyrolysis without any downstream catalytic treatment (bio-oil ∼39.0-40.0 wt % and permanent gases 24.6-26.6 wt %). Ex situ reduced and passivated MoNi/γ-Al2O3 led to the lowest organic phase and highest aqueous phase yields. The product distribution between the two liquid phases was also modified by the catalytic upgrading experiments carried out, according to heteronuclear single-quantum correlation (HSQC), total correlation spectroscopy (TOCSY), and NMR analyses. The detailed composition distribution reported here shows the chemical production potential of this residue and serves as a starting point for subsequent valorizing technologies and/or processes in the food and nonfood industry beneficiating society, environment, economy, and research.

Catalytic upgrading of cow manure pyrolysis vapors over zeolite/carbon composites prepared from coal gasification fine slag: High quality bio-oil obtaining and mechanism investigation

The resource utilization of solid waste not only reduces the environmental pollution, but also reduces the use of fossil energy. In this study, three low-cost zeolite/carbon composites, including Y-type zeolite/carbon, Beta zeolite/carbon and ZSM-5 zeolite/carbon, were prepared from coal gasification fine slag (CGFS), which were used for catalytic upgrading of pyrolysis vapors of cow manure (CM). The composition and distribution of products from the catalytic pyrolysis of CM over different types composites were explored, and the relationship between catalysts structure and product selectivity was clarified. The results show that different types of catalysts have virous effects on the composition and distribution of products due to different physiochemical structures such as pore size and acid site. Among them, ZSM-5 zeolite/carbon is more conducive to the formation of monocyclic aromatics due to its shape selective catalysis, Beta zeolite/carbon has relatively large pore size and has high selectivity for polycyclic aromatics, and Y-type zeolite/carbon is more conducive to the removal of nitrogen and oxygen-containing compounds. Moreover, vanillin, glucose and valine, which are the main components of lignin, cellulose and protein in CM were selected as model compounds to reveal the reaction mechanism of catalytic upgrading. The results of this study can provide reference and theoretical guidance for the comprehensive utilization of solid waste and the development of low-carbon green industry.

Ex-situ catalytic upgrading of pyrolysis vapors using mixed metal oxides

Ex-situ catalytic fast pyrolysis (CFP) was employed to produce bio-oils from beech wood. The effect of Nb-based mixed oxides (with second metal oxide = W, Al or Mn) in upgrading the pyrolysis vapors was compared to an H-ZSM-5 catalyst and to non-catalyzed pyrolysis. The catalysts acidic properties were assessed by NH3-TPD and FTIR of adsorbed pyridine. The bio-oils obtained were characterized by Karl-Fischer titration, GPC, CHNS analyses, 13C-NMR, GC–MS, GCxGC–MS. In spite their very different acidic properties, the NbxMnyOz catalyst (with essentially Lewis acid sites) exhibited similar performances as H-ZSM-5 (that presents a high density of Brønsted sites), in terms of liquid phase selectivity and reduction of oxygen content in the bio-oils produced. These observations were accompanied by a reduction of compounds such as acids, aldehydes, ketones, ethers and sugars that contribute to the detrimental properties of bio-oils. Finally, the results suggest that the Lewis acid sites of NbxMnyOz are converted into Brønsted sites in the presence of water vapor produced by pyrolysis of wood, whereas the strongest Brønsted sites of H-ZSM-5 have a limited impact on the upgrading process due to their limited accessibility for most components of pyrolysis vapors.

Deoxygenation of wheat straw fast pyrolysis vapors over Na-Al2O3 catalyst for production of bio-oil with low acidity

Catalytic upgrading of pyrolysis vapors from wheat straw over Na2CO3 impregnated γ-Al2O3 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 CO2/g catalyst, at 80% lower catalyst acidity. Analytical pyrolysis using a micro-pyrolyzer showed that Na-Al2O3 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-Al2O3 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-Al2O3 was highly effective in reducing the acidity of the bio-oils. Total acid numbers (TAN) as low as ~1–4 mgKOH/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-Al2O3 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-Al2O3 was regained by coke combustion, the Na remained well dispersed on the support, and the catalyst maintained its capacity for CO2 adsorption at 500 °C after six reaction/regeneration cycles.

Insights into the scalability of catalytic upgrading of biomass pyrolysis vapors using micro and bench-scale reactors

Comparison of catalytic upgrading of pyrolysis vapors in microscale Py-GC and continuous bench-scale reactor provides qualitative agreement in catalyst ranking between scales.

Flow and reaction characteristics on catalytic upgrading of biomass pyrolysis vapors in novel cyclone reactors

To improve the catalytic upgrading efficiency of biomass pyrolysis vapors and reduce secondary cracking of aimed products in current conventional reactors, a novel cyclone reactor was designed for the gas (biomass pyrolysis vapors)-solid (catalysts) heterogeneous reaction. The contact effect of gas-solid two-phase could be increased in the cyclonic flow field, and the separation between the gas products and catalysts occurs while flowing down due to the centrifugal force in short residence time. The rapid separation reduces secondary cracking effectively. In this study, the catalytic upgrading of pyrolysis vapors in the cyclone reactor were investigated from the aspect of fluid dynamics, residence time distribution and catalytic reaction by CFD simulation combining with the experimental method. The results indicate that in the reaction chamber of the cyclone reactor the concentration gradient of catalysts decreases gradually while flowing down. The cyclonic flow is intensified due to the guided vanes in the middle part of the reactor, and the separation effect is improved remarkably. The effects of outlet structures were investigated based on the residence time distribution and the product selectivity, the structure of Case 2 that has a vertical catalyst outlet and a horizontal gas outlet is better. The residence time of catalysts in Case 2 is 1.0s–2.0s. And the overall mass fraction of the bio-oil is 54%.

In situ catalytic upgrading of pyrolysis vapours from vacuum pyrolysis of rape straw over La/MCM-41

By combining the large pore size of MCM-41 and the adjustable acid property of La, La/MCM-41 catalysts with La loading mass fractions of 1%, 5% and 10% were prepared and used in the catalytic upgrading of pyrolysis vapours from vacuum pyrolysis of rape straw to obtain high-value bio-oil. MCM-41 zeolite before and after the La loading was characterized in detail by TEM, Py-IR and TG. The characterization data showed that the amount of Brönsted and Lewis acid sites on the surface of La/MCM-41 increased. The highest hydrocarbon content (35%), and the highest higher heating value (34 MJ kg−1) were obtained at a La loading of 5% (La(5)/MCM-41). This may be closely related to the promotion of the reaction efficiency of the active sites with proper acid concentrations. Simultaneously, the coke content of the catalyst decreased further, and the selectivity for the high-value aromatic hydrocarbons increased. Considering the suitable concentration of La(5)/MCM-41 with strong acidity and stability, it is more appropriate for use in the upgrading of pyrolysis vapour for liquid fuel production.

Numerical simulation and experiment on catalytic upgrading of biomass pyrolysis vapors in V-shaped downer reactors

Catalytic upgrading of biomass pyrolysis vapors is an effective utilization technology of biomass energy. Based on the disadvantages of commonly used reactors, the V-shaped downer reactors were designed to increase gas-solid two-phase turbulent intensity, contact frequency and then increase the catalytic efficiency in short residence time. The catalytic upgrading of pyrolysis vapors in V-shaped downer reactors in terms of hydrodynamics, chemical reaction and residence time distribution were analyzed by CFD simulation and experiment. The results indicate that the solid concentration gradient decreases while flowing down. The overall mass fraction of the bio-oil vapors is around 50%. The mean residence time of catalysts in the V-shaped reactor is 2.0 s–3.0 s. The effects on product yield and residence time distribution were investigated for optimizing product selectivity and the performance of catalysts. In this paper the optimal flow rates of gas and catalysts are vg = 1.2 m s−1, vs = 0.4 m s−1.

Preparation of hierarchical HZSM-5 based sulfated zirconium solid acid catalyst for catalytic upgrading of pyrolysis vapors from lignite pyrolysis

H5 was developed to mesoporous system via alkali treatment, and sulfated zirconia (SZr) modified hierarchical HZSM-5 (AT0.2/H5) catalysts (named AT0.2/SZxH5) were successfully prepared by a series of post-treated method followed by Zr(NO3)4·5H2O and H2SO4 as active component. The innovative approach really enhanced acidity of AT0.2/H5 support, which results from the interaction of the sulfate groups attached to zirconia that doped on MFI framework with silanol groups. Adding active component can not only compensate for the loss of acid sites caused by NaOH treatment, but also re-develop more active sites owing to the formation of SZr. Meanwhile, NH3-TPD showed higher strong acid sites and weak acid sites in AT0.2/SZ6:1H5 than other prepared catalysts. The catalytic activity in converting lignite pyrolysis volatiles to light aromatics, including benzene, toluene, ethylbenzene, xylene and naphthalene (BTEXN), correlates well with the enhanced acidity. Compared with H5, the yield of light aromatics increased significantly from 15.2 to 19.3 mg/g over AT0.2/SZ6:1H5 at 600 °C. According to the characterization of N2 adsorption–desorption, SEM, and XRD, both the S species as SO42− and Z species as ZrO2 improved the textural properties of the support itself. Besides, the molar ratio of S/Zr was in direct proportion to the yield of BTEXN in a certain range, and 6:1 exhibited the optimal catalytic performance. The prepared solid acid catalyst provides a promising strategy to directional prepare light aromatics during lignite catalytic pyrolysis.

Catalytic upgrading of pyrolysis vapours: Effect of catalyst support and metal type on phenolic content of bio-oil

Abstract Bio-oil from low-cost and renewable lignocellulosic biomass is a complex mixture of organic compounds and water. It is necessary to selectively control the biomass pyrolysis pathways to obtain specific bio-oils rich in value-added chemicals. Microporous and mesoporous catalysts can be good candidates for the catalytic pyrolysis of biomass leading to the production of valuable components such as aromatic hydrocarbons and phenolics. In this study, in-situ catalytic upgrading of pyrolysis vapours from acid pre-treated walnut shell was carried out in a lab scale fixed bed reactor with microporous nickel or cobalt impregnated Zeolite Socony Mobil–5 and mesoporous aluminum or iron impregnated Santa Barbara Amorf-15 catalysts. The effects of catalyst modification on product yields, bio-oil quality and the variation of the phenolic compounds in pyrolytic-oil were examined using elemental analysis, gas chromatography and mass spectrometry. The major improvement in the bio-oil quality by the catalyst addition was the reduction of the oxygen content of the bio-oil's organic fraction and the increase in valuable chemicals (aromatics and phenolics), while the total liquid yield (bio-oil) decreased. Catalysts also increased the gaseous product yields. In comparison to non-catalytic experiments, all the Proton-exchanged Zeolite Socony Mobil-5 catalysts decreased both the total liquid and the total organic content yield due to the H+-form zeolite catalysing hydrocarbon conversion reactions. Compared to Proton-exchanged Zeolite Socony Mobil-5, the metal impregnated catalysts yielded less water, but favoured the formation of gas products. It was evident that impregnation with metals changed the mechanism of oxygen removal. Cobalt/Proton-exchanged Zeolite Socony Mobil-5 favoured the formation of carbon dioxide over carbon monoxide, while nickel/Proton-exchanged Zeolite Socony Mobil-5 favoured the formation of carbon monoxide over carbon dioxide. When using Proton-exchanged Zeolite Socony Mobil-5 instead of silica sand, the guaicols and syringol that are formed from the thermal decomposition of the lignin fraction in the sulphuric acid treated walnut shell are significantly reduced and are mainly converted to alkylated phenols and aromatic and polyaromatic hydrocarbons. With the impregnation of metals on the Santa Barbara Amorf-15, the selectivity of the Santa Barbara Amorf-15 exhibited a shift from catechol- and pyrogallols-type compounds to alkylated phenols, especially at 10% aluminum, 30% and 50% iron metal loadings. As a result, the bio-oil composition and quality can be improved by utilizing different metals and metal impregnation ratios during catalytic upgrading. According to the preliminary economic analysis, pyrolysis oil production cost predicted from catalytic pyrolysis of walnut shell is higher than catalytic pyrolysis of woody biomass because of lower pyrolysis oil yield of walnut shell.

Catalytic upgrading of pyrolysis vapors from lignite over mono/bimetal-loaded mesoporous HZSM-5

HZSM-5 was modified via alkaline treatment and wet impregnation method which loading transition metals (Co, Mo–Co and Ni–Co). The performance of catalysts for the catalytic fast pyrolysis of lignite was tested in a drop tube reactor at 600 °C. In comparison to non-catalytic experiment, the chemical composition of upgrading tar was obviously simplified, which mainly contains light aromatics such as benzene, toluene, ethylbenzene, xylene and naphthalene (BTEXN). The yield of BTEXN was significantly increased from 12.9 to 26.4 mg/g when Ni/Co-H-5 was used. Meanwhile, the Ni/Co-H-5 treated by NaOH solution achieved considerable deoxygenation performance (86.6%) than other ones. The addition of bimetallic Mo–Co or Ni–Co significantly enhanced the BTEXN selectivity of HZSM-5. Ni promoted H2 formation in gaseous product and caused the decrease of naphthalenes yield. Whereas the yields of toluene and o-xylene increased after the pyrolysis vapors pass through Mo/Co-H-5. The zeolite treated by NaOH solution (AT-HZSM-5) favors the generation of aromatics and phenolics, conversely naphthalene derivatives. Moreover, AT-Mo/Co-H-5 and AT-Ni/Co-H-5 inhibited the coke formation. A catalytic pathway was also proposed to describe the diffusion process of pyrolysis vapors on the active site of catalyst.

Numerical simulation of catalytic upgrading of biomass pyrolysis vapours in a FCC riser

Catalytic upgrading of biomass pyrolysis vapours is a potential method for the production of hydrocarbon fuel intermediates. This work attempts to study the catalytic upgrading of pyrolysis vapours in a pilot scale FCC riser in terms of hydrodynamics, residence time distribution (RTD) and chemical reactions by CFD simulation. NREL's Davison Circulating Riser (DCR) reactor was used for this investigation. CFD simulation was performed using 2-D Eulerian–Eulerian method which is computationally less demanding than the alternative Euler-Lagrangian method. First, the hydrodynamic model of the riser reactor was validated with the experimental results. A single study of time-averaged solid volume fraction and pressure drop data was used for the validation. The validated hydrodynamic model was extended to simulate hydrodynamic behaviours and catalyst RTD in the Davison Circulating Riser (DCR) reactor. Furthermore, the effects on catalyst RTD were investigated for optimising catalyst performance by varying gas and catalyst flow rates. Finally, the catalytic upgrading of pyrolysis vapours in the DCR riser was attempted for the first time by coupling CFD model with kinetics. A kinetic model for pyrolysis vapours upgrading using a lumping kinetic approach was implemented to quantify the yields of products. Five lumping components, including aromatic hydrocarbons, coke, non–condensable gas, aqueous fraction, and non–volatile heavy compounds (residue) were considered. It was found that the yield of lumping components obtained from the present kinetic model is very low. Thus, the further research needs to be carried out in the area of the kinetic model development to improve the yield prediction.

Catalytic Upgrading of Biomass-Derived Compounds via C–C Coupling Reactions: Computational and Experimental Studies of Acetaldehyde and Furan Reactions in HZSM-5

Catalytic C–C coupling and deoxygenation reactions are essential for upgrading of biomass-derived oxygenates to fuel-range hydrocarbons. Detailed understanding of mechanistic and energetic aspects of these reactions is crucial to enabling and improving the catalytic upgrading of small oxygenates to useful chemicals and fuels. Using periodic density functional theory (DFT) calculations, we have investigated the reactions of furan and acetaldehyde in an HZSM-5 zeolite catalyst, a representative system associated with the catalytic upgrading of pyrolysis vapors. Comprehensive energy profiles were computed for self-reactions (i.e., acetaldehyde coupling and furan coupling) and cross-reactions (i.e., acetaldehyde + furan) of this representative mixture. Major products proposed from the computations are further confirmed using temperature controlled mass spectra measurements. The computational results show that furan interacts with acetaldehyde in HZSM-5 via an alkylation mechanism, which is more favorable than...

Catalytic upgrading of pyrolysis vapors from Jatropha wastes using alumina, zirconia and titania based catalysts.

The objective of this study was to catalytically upgrade bio-oil from organic vapors of Jatropha wastes using Py-GC/MS. Catalytic testing included Al2O3, ZrO2, TiO2 (rutile, T1) and TiO2 (anatase, T2) supporter catalysts modified with transition metals (Pd, Ru or Ni) by impregnation method. In non-catalytic runs, the main vapor products were fatty acids (60.74%). With the presence of Al2O3 based catalysts, carboxylic acids were obviously reduced to 0.76-19.61% while hydrocarbons were the main products (42.00-64.06%). Comparing among four supporters, total hydrocarbon yields increased with presence of all catalysts. Higher yields were obtained by T2>Al2O3>CA>NiCA>RuCA catalysts. Al2O3 and T2 supports were the most effective for increased hydrocarbons while decreased oxygenated compounds (15%) which is one of the primary aims of this study. The result indicating that high surface area resulted in better catalytic activity but also adversely promoted N-compounds. Therefore these catalysts can be applied to improve properties of pyrolytic products.

Packed-Bed Catalytic Cracking of Oak-Derived Pyrolytic Vapors

Catalytic upgrading of pyrolysis vapors derived from oak was carried out using a fixed-bed catalytic column at 425 °C. The vapors were drawn by splitting a fraction from the full stream of vapors produced at 500 °C in a 5 kg/h bench-scale fast pyrolysis reactor system downstream from the cyclone separator. The placement of the fixed-bed column was varied within the condenser train to determine the effect of temperature, residual water, solids, and oxygenated components of the approach vapor stream on the upgraded product quality. The upgraded liquid was collected by immediate contact with a dry ice acetone bath, complimented by a secondary collection system comprised of a methanol spray condenser. Quantitative gas chromatography/mass spectroscopy (GC/MS) analysis of the recovered liquid showed a substantial decrease of oxygen-containing species with a significant increase in carbon-rich (≥C6) aromatic hydrocarbons. The extent of deoxygenation was location-specific and dependent upon temperature and the re...

Catalytic upgrading of biomass fast pyrolysis vapors with titania and zirconia/titania based catalysts

Fast pyrolysis of poplar wood followed with catalytic upgrading of the pyrolysis vapors was performed using analytical pyrolysis–gas chromatography/mass spectrometry (Py-GC/MS). The catalysts applied in this study were three commercial meso- or macroporous catalysts (TiO 2 (Rutile), TiO 2 (Anatase) and ZrO 2&TiO 2) and their modified ones with incorporation of Ce, Ru or Pd. These catalysts displayed different catalytic effects on the pyrolytic products. The TiO 2 (Rutile) based catalysts, especially the Pd/CeTiO 2 (Rutile), were effective to convert the lignin-derived oligomers to monomeric phenolic compounds, with the phenols increasing from 25.6% in the non-catalytic products to 37.2% after catalyzed by the Pd/CeTiO 2 (Rutile). The ZrO 2&TiO 2 based catalysts were the most effective to change the pyrolytic products. They significantly reduced the phenols, acids and sugars, and meanwhile, increased the hydrocarbons, linear ketones and cyclopentanones. The highest hydrocarbon content of 13.1% was obtained by the ZrO 2&TiO 2, compared with only 0.1% in the non-catalytic products. The catalytic effects of the TiO 2 (Anatase) based catalysts were between that of the TiO 2 (Rutile) and ZrO 2&TiO 2 based catalysts.

Catalytic pyrolysis of biomass for biofuels production

Abstract Fast pyrolysis bio-oils currently produced in demonstration and semi-commercial plants have potential as a fuel for stationary power production using boilers or turbines but they require significant modification to become an acceptable transportation fuel. Catalytic upgrading of pyrolysis vapors using zeolites is a potentially promising method for removing oxygen from organic compounds and converting them to hydrocarbons. This work evaluated a set of commercial and laboratory-synthesized catalysts for their hydrocarbon production performance via the pyrolysis/catalytic cracking route. Three types of biomass feedstocks; cellulose, lignin, and wood were pyrolyzed (batch experiments) in quartz boats in physical contact with the catalysts at temperature ranging from 400 °C to 600 °C and catalyst-to-biomass ratios of 5–10 by weight. Molecular-beam mass spectrometry (MBMS) was used to analyze the product vapor and gas composition. The highest yield of hydrocarbons (approximately 16 wt.%, including 3.5 wt.% of toluene) was achieved using nickel, cobalt, iron, and gallium-substituted ZSM-5. Tests performed using a semi-continuous flow reactor allowed us to observe the change in the composition of the volatiles produced by the pyrolysis/catalytic vapor cracking reactions as a function of the catalyst time-on-stream. The deoxygenation activity decreased with time because of coke deposits formed on the catalyst.

Rapid Pyrolysis of Olive Residue. 2. Effect of Catalytic Upgrading of Pyrolysis Vapors in a Two-Stage Fixed-Bed Reactor

The upgrading of the rapid pyrolysis vapors was performed using various catalysts (clinoptilolite (a natural zeolite, NZ), ZSM-5, H−Y) with catalyst/feed ratios of 0.05, 0.1, 0.15, 0.20, and 0.25 in the catalyst bed temperature range of 350−500 °C on the product distributions. The catalytic treatment with synthetic zeolites provided enhancement of the gas yields and reduction of the oil yields. Moreover, the high catalyst/feed ratio was favored to increase of gas yields. ZSM-5 was very effective in gas production, whereas NZ was in bio-oil production without any severe coking, compared to synthetic zeolites. H−Y showed a higher tendency of formation of coke and tar. Moreover, a catalyst bed temperature of >450 °C caused enhancement of the gas yields and reduction of the oil yields. After application of catalytic treatment, the long chains of alkanes and alkenes of the pyrolysis oil were converted to lower-weight hydrocarbons. An increase of aliphatics, aromatics, and olefins and a sharp decrease of asphal...