Pyrolysis Bio-oil Research Articles

Investigation on bio-oil pyrolysis with Ni/Al2O3 blending: Influence of the blended catalyst on coke formation

Bio-oil can be converted into syngas, chemicals, and carbon materials via thermochemical and/or catalytic conversion routes. However, coking remains a significant challenge during the heating of bio-oil. In this study, we investigated the influence of pre-blending Ni/Al2O3 and bio-oil in an in-situ catalytic pyrolysis process on the coking behaviours of bio-oil. Our results indicate that the presence of Ni/Al2O3 significantly reduces coke yield and increases gas yield (for example, by a 14.2 % reduction in coke and a 44.1 % increase in gas at 700 °C). This is attributed to the suppression of the cross-linking reactions responsible for coke formation through the pre-elimination of O-containing groups into CO and CO2. Additionally, pre-blending of Ni/Al2O3 is highly desirable for transforming or stabilising the highly reactive substances in the early pyrolysis stage of bio-oil, minimising their tendency to polymerise. Furthermore, the presence of Ni/Al2O3 facilitates the cracking of C–H bonds and self-reforming of bio-oil, increasing H2 production (which is increased by 42.3 % at 700 °C), thereby promoting the breakage of side chains of lignin-derived aromatics and the hydrogenation of unsaturated structures, suppressing the formation of small aromatic systems in coke (<6 rings). Nevertheless, enhanced formation of alkyl-aryl C–C bonds during aromatisation leads to more condensed coke structures.

Importance of interaction of varied components in formation of carbon nanospheres via bio-oil pyrolysis

Bio-oil has a high tendency towards coking upon heating, which can be the feedstock for production of carbonaceous materials with particular morpholpgy. Herein, production of carbon nanospheres via bio-oil pyrolysis at 800–1100 °C was conducted. The results revealed that the increasing temperature promoted the formation of carbon-rich structures of the nanospheres. The primary precursors for carbon spheres were identified as small gas-phase molecules. The competitive production of carbon spheres and flake carbon was observed, while carbon spheres gradually became the main product at higher pyrolysis temperature (>1000 °C). Furthermore, the abundance of aromatic organics was a critical factor for carbon nanosphere formation. Among the typical model components, the yields of carbon nanosphere at 1100 °C followed the order: guaiacol (38.2 wt%) > furfural (36.6 wt%) > heavy components (28.5 wt%). While acetic acid, acetone, and methanol as model compounds showed a yield of 0 wt%. The degree of interactions among bio-oil components also influenced the yield and properties of the produced carbon nanospheres. The addition of guaiacol to bio-oil facilitated the production of carbon spheres and graphitization, achieving a substantial yield of 12.7 wt% at 900 °C. However, the addition of methanol leads to a decrease in yield of carbon nanospheres.

Production of pyrolytic lignin for the phenolic resin synthesis via fast pyrolysis

Recycling of waste wood into resol type phenol-formaldehyde (PF) resins via fast pyrolysis was demonstrated. Waste wood collected from the building demolition site in Finland was pyrolyzed with 20 kg/h circulating fluidized bed pyrolysis pilot unit. Pilot was operated with high organic liquid yield (60 wt% on average) and the produced fast pyrolysis bio-oil was fractionated by water addition into aqueous phase and water insoluble phase. The obtained fractions were characterized, and the water-insoluble viscous lignin fraction was used in the synthesis of PF-resins. Commercial phenol was successfully replaced by pyrolytic lignin fraction at 10 wt%, 20 wt%, 30 wt%, 40 wt% and 50 wt% producing resins of low in free formaldehyde content, but resins with high replacement ratio exhibited higher viscosities. The use of H2O/n-butanol mixture as solvent at a ratio 70:30 wt/wt% proved capable to prolong the storage time of the resin and helped to maintain the viscosity at acceptable values for at least 2 weeks before their use in the targeted application. Finally, the gluing performance of the resins was evaluated by measuring the tensile shear strength of lap joints formed by gluing 5 mm thick beech wood veneers. All the produced resins fulfilled a dry strength limit of ≥ 10 N/mm2. Wet strength limit ≥ 7 N/mm2 was fulfilled by the resins with the replacement ratio up 40 wt%, but resins with replacement ratio of 50 wt% had somewhat reduced wet strength. These results confirm a promising protentional application of pyrolysis derived lignin fraction in phenolic wood adhesives, at least in dry conditions.

Plating the hot potato: how to make intermediate bioenergy carriers an accelerator to a climate-neutral Europe

BackgroundWith sustainable bioenergy in the European energy mix, intermediate bioenergy carriers (IBC) become of growing importance, as they can ensure a more efficient utilisation of biomass feedstocks from agricultural and forest residues. A high potential for market uptake is foreseen for fast pyrolysis bio-oil (FPBO), one of several IBCs. While facing the chicken and egg problem in market entry, the aim of this study was the development of adequate strategies to support market implementation. The case study findings and methodological approach can provide policymakers, industry, and a broader audience with a vision for addressing similar challenges in market adoption of innovations in the bioeconomy and beyond. Therefore, we tested a new PESTEL + I approach and its practical applicability to an IBC value chain.ResultsWith an adopted PESTEL method, we analysed a promising value chain in which FPBO is produced from sawdust in Sweden and Finland, transported to the Netherlands and upgraded and marketed as a marine biofuel. Our results show that the market uptake of IBCs such as FPBO and subsequently produced biofuels is above all driven by the European Renewable Energy Directive II (RED II). In Annex IX Part A, sawdust is listed as a feedstock for advanced biofuels, which can be double counted towards the 14% renewable energy share goal in the transport sector in 2030. To support the use of advanced biofuels in the maritime and aviation sector, the proposal for revision of RED II 2021 contains a new multiplier (1.2x) for fuels delivered to these sectors, while all other multipliers are deleted. These legal European obligations and implementation into national law of member states create strong incentives for many downstream market actors to use advanced biofuel. However, technological challenges for FPBO use still hamper fast market introduction.ConclusionsOvercoming technology challenges and the creation of long-term validity of guidelines and regulatory framework will create stable market conditions, investment security and finally stimulate long-term offtake agreements between feedstock providers, technology developers and downstream customers. The approach and findings can provide a vision to overcome similar challenges in other bioeconomy innovations’ market uptake and beyond.

Petroleomics Approach to Investigate the Composition of Upgrading Products from Pyrolysis Bio-Oils as Determined by High-Field FT-ICR MS

Petroleomics Approach to Investigate the Composition of Upgrading Products from Pyrolysis Bio-Oils as Determined by High-Field FT-ICR MS

Comprehensive investigation on fast pyrolysis of waste Lotus shells to produce valuable products: Pyrolysis characteristics, reaction mechanism and economic analysis

Lotus shells (LS) represent an abundant, underutilized renewable resource with significant potential for producing bio-based fuels and chemicals. Pyrolysis emerges as an effective means to maximize the value derived from LS waste. This study assessed the behavior, kinetics of LS pyrolysis for bioenergy production through thermogravimetric analysis (TGA), model-free and model methods. The product distribution resulting from LS fast pyrolysis and the physicochemical properties of the derived products were comprehensively investigated. A plausible reaction mechanism for LS pyrolysis was proposed, followed by an estimation of the associated costs for bioenergy production through pyrolysis. The activation energy (Eα) for LS calculated through Flynn-Wall-Ozawa (FWO), Kissinger-Akahira-Sunose (KAS), and Friedman (FR) methods was 197.36 kJ/mol, 193.66 kJ/mol, and 197.16 kJ/mol, respectively. The kinetic reaction model for LS pyrolysis was represented by the equation f(α) = α−26.59(1-α)12.35[-ln(1-α)]−27.26, indicating the dominance of a diffusion model and nucleation mechanism in the LS pyrolysis process. Notably, the fast pyrolysis bio-oil derived from LS mainly comprised phenols (34.73 % at 300 °C), acids (42.33 % at 600 °C), and nitrogenous compounds (27.40 % at 800 °C), and the gaseous products primarily consisted of H2, CH4, CxHy, CO, and CO2. Biochar derived from LS exhibited abundant functional groups and mesoporous structure, and its moderate C/N ratio and low H/C ratio indicated potential for soil remediation. Furthermore, the high heating value (21.55–27.01 MJ/kg) of LS biochar exceeded that of Zhaotong lignite, demonstrating its favorable combustion characteristics. This study lays the theoretical foundation for the efficient treatment and high-value utilization of Lotus shells.

The impact of various catalysts on pyrolysis bio-oil characteristics and catalyst coking behavior of corn stover

ABSTRACT Biomass has immense potential to address energy and environmental issues. Catalytic pyrolysis is an effective technology for utilizing biomass. Six catalysts (CaO, Al2O3, Fe2O3, MCM-41, HZSM-5, and red mud(RM)) were used to pyrolyze corn stover in a fixed-bed reactor. Six catalysts (CaO, Al2O3, Fe2O3, MCM-41, HZSM-5, and red mud (RM)) were used in a fixed-bed reactor. The feedstock-to-catalyst (FCR) ratio was adjusted to optimize the catalytic effect. The comprehensive evaluation of the catalysts was carried out by analyzing the deoxygenation effect, liquid yield, and catalyst coke accumulation behavior through TG, GC-MS, SEM/EDS, and XRD techniques. The study revealed that superior deoxygenation performance among the six investigated were HZSM-5, CaO, and RM. At the highest FCR (2:1), the liquid yield and deoxygenation effect of CaO are both at their optimal state simultaneously. The bio-oil yield reached 51.98%, but it has a coke accumulation of 27.07% by TG. MCM-41 and HZSM-5 exhibited more severe coking with coke contents of 8.14% and 8.04%, respectively, along with higher maximum heat loss temperature, upon dichloromethane extraction. The relative peak areas of alkanes in the coke accumulation were more than 50% except for RM, which the main component of the latter was polycyclic aromatic hydrocarbons (78.43%). By comparing the bio-oil characteristics and carbon accumulation behavior of different catalysts, it provides a reference for the study of carbon accumulation in pyrolysis catalysts.

Pyrolysis of the bio-oil blended with Ni/Al2O3: Evolution of heavy components in the bio-oil

Heavy components in bio-oils pose significant challenges for their utilisation through thermal conversion, as they are highly reactive and prone to polymerisation upon heating. This study investigates the formation and reduction of heavy components during ex-situ and in-situ catalytic pyrolysis of bio-oil over Ni/Al2O3. The heavy components present in the volatile products from bio-oil pyrolysis can be cracked for ex-situ catalysis. In contrast, in-situ catalysis results in catalyst deactivation due to the polymerisation of bio-oil components. However, at temperatures >700 °C, as thermal cracking reactions dominate during bio-oil pyrolysis, in-situ catalysis can further suppress the polymerisation among bio-oil components. As a result, the tar and coke yields decrease by 9.8 wt% and 2.7 wt% at most.

The effect of citric acid pretreatment on composition and stability of bio-oil from sugar cane residues using a continuous lab-scale pyrolysis reactor

This study outlines the effect of citric acid leaching on the quality and stability of fast pyrolysis bio-oils from sugarcane bagasse (SCB) and sugarcane trash (SCT). The quality of bio-oil was probed by GC-MS analysis, elemental composition, higher heating value, water and solids content, pH, dynamic viscosity and stability (ageing). Pyrolysis was performed at 500 °C in a fully controlled, continuously operated plant with a biomass throughput of ca. 300 g.hr−1. While citric acid leaching causes a decrease of the average bio-oil yield with 5%, it does not lead to a bio-oil with improved fuel-related properties. However, the bio-oil composition became more advantageous in light of its biorefining. Indeed, citric acid leaching led to an increased levoglucosan concentration – a promising platform chemical – of 17% for SCB and of to 35% for SCT (based on relative abundance in GC-MS). In tandem, the concentration of carboxylic acids and phenols in the bio-oil decreased after citric acid leaching, which is beneficial for downstream purification of levoglucosan. Regarding the non-condensable gases, CO and CO2 represented between 88% and 91% by weight of the total non-condensable gases produced in pyrolysis. Therefore, the results of this study demonstrate that optimized biomass demineralization pretreatment with citric acid could produce bio-oil at high yield and rich in high-value chemical compounds like levoglucosan. Biomass demineralization pretreatment however, does not result in bio-oil with improved quality for fuel purposes, nor does it necessarily lead to bio-oil having higher stability.

From waste to food and bioinsecticides: An innovative system integrating Tenebrio molitor bioconversion and pyrolysis bio-oil production

To achieve a waste-free clean production, the present study aimed to valorize an underused agroindustrial byproduct (rice bran) by mealworms bioconversion and produce bio-oil from pyrolysis of insect excreta (frass) as bioinsecticide. To reach the first goal, the suitability of rice bran (RB) versus standard diet, wheat bran (WB), was examined by determining feed conversion, growth performance, and nutritional profile of T. molitor larvae. RB diet was an appropriate feed substrate for breeding mealworms, as evidenced by their high survival rates, optimal feed conversion parameters, and its capability to support the growth and life cycle of this insect. Besides, RB did not affect soluble larval protein content but modified crude fat content and fatty acid profile. In order to address the second aim, egested frass from RB and WB were subjected to pyrolysis to obtain bio-oils. The main compound was acetic acid (≈37%) followed by 1,6-anhydro-β-d-glucopyranose (from 16 to 25%), as measured by GC-MS analysis. Nitrogen-containing chemicals accounted for ≈10%. Frass bio-oils could represent a novel source of bioinsecticides due to their bioeffectiveness in insect pests of economic importance (Plodia interpunctella and Tribolium castaneum) and medical interest (Culex pipiens pipiens). For P. interpunctella adults, frass bio-oils produced insecticidal activity by fumigant and contact exposure whereas for T. castaneum adults, just fumigant. By a miniaturized model that simulates semireal storage conditions, it was seen that, on T. castaneum, frass RB bio-oil generated higher repellent effect than frass WB. Finally, bio-oils proved to have larvicidal activity against Cx. p. pipiens.

Effects of different pretreatment methods on millet straw and millet bran for fuel properties and pyrolysis bio-oil

Effects of different pretreatment methods on millet straw and millet bran for fuel properties and pyrolysis bio-oil

Quantitative Low-Field 19 F Nuclear Magnetic Resonance Analysis of Carbonyl Groups in Pyrolysis Oils.

Pyrolysis bio-oils, one of the products of lignocellulosic biomass pyrolysis, have the potential to be widely used as fuels. The chemical composition of bio-oils is very complicated as they contain hundreds, if not thousands, of different, mostly oxygen-containing, compounds with a wide distribution of physical properties, chemical structures, and concentrations. Detailed knowledge of bio-oil composition is crucial for optimizing both the pyrolysis processes and for any subsequent upgrading into a more viable fuel resource. Here we report the successful use of low-field, or benchtop, nuclear magnetic resonance (NMR) spectrometers in the analysis of pyrolysis oils. Pyrolysis oils from four different feedstocks were derivatized and analyzed using 19 F NMR techniques. The NMR results compare favorably with titrations for total carbonyl content. In addition, the benchtop NMR spectrometer proves able to reveal key spectral features, thus allowing the quantification of different carbonyl groups, such as aldehydes, ketones and quinones. Benchtop NMR spectrometers are typically compact, cheaper than their superconducting counterparts and do not require cryogens. Their use will make NMR analysis of pyrolysis oils easier and more accessible to a wide range of different potential users.

Bio-oil production from rubber seed cake via pyrolysis: Process parameter optimization and physicochemical characterization

Non-edible rubber (Hevea brasiliensis) seed cake (RSC) obtained as a by-product during oil extraction from rubbed seed can be utilized for bio-oil production. This study represents the evaluation of the potential of RSC as a novel matrix for bio-oil production via pyrolysis using a pyrolyzer. The optimum yield of RSC pyrolytic bio-oil (59.94 wt%) and carbon-rich RSC biochar (27.03 wt%) was obtained during pyrolysis at 500 °C temperature for 75 min at a heating rate of 20 °C/min. Thermogravimetric analysis (TGA), proximate analysis, ultimate analysis, Fourier Transform Infrared (FT-IR), calorific value of RSC were performed and these results confirm that RSC is a hydrocarbon-rich feedstock which can be exploited to produce bio-oil and biochar. The yield and characteristics of the products were significantly impacted by temperature during the thermal decomposition of RSC. GC–MS, FT-IR, CHNS elemental analysis etc. methods were used to determine the composition of RSC pyrolytic bio-oil and its distillate product as well as XRD and SEM images studies were employed to characterize the carbon-rich RSC biochar. Various value added organic chemicals including phenolic compounds, hydrocarbon (aliphatic/aromatic), esters, oxygenated compound and nitrogen containing compounds were identified in bio-oil and subsequent product using GC–MS and related techniques. An in depth physico-chemical-thermal analysis indicates that RSC bio-oil can be regarded as a suitable feedstock for the production of industrially important chemicals including fuel.

Contribution of LDI and MALDI for the Characterization of a Lignocellulosic-Based Pyrolysis Bio-Oil.

In recent years, various alternatives to fossil fuels have been developed. One of them involves the production of bio-oils from lignocellulosic-based biomass through pyrolysis. However, bio-oils present numerous heteroatoms and, in particular, oxygen atoms that need to be removed by an upgrading process. To optimize these processes, it is necessary to have good knowledge of the composition of the bio-oils at the molecular level. This work aims to establish the usefulness of laser desorption ionization (LDI) and matrix-assisted laser desorption/ionization (MALDI) techniques on lignocellulosic biomass-based bio-oils. Using a Fourier transform ion cyclotron mass spectrometer (FTICR MS), we showed that MALDI gives more information than LDI. The selectivity of a series of MALDI matrices was investigated, showing that some matrices are selective toward compound families and others ionize a wider range of compounds. In this study, nine proton-transfer matrices and three electron-transfer matrices were used and compared to results obtained in LDI. Dithranol, acetosyringone, and graphene oxide were the three promising matrices selected from all matrices, giving an overall characterization of oxygenated classes in a bio-oil. They allowed the ionization of many more species covering a wide range of polarity, aromaticity, and mass with a homogeneous relative intensity for all molecular classes such as lignin-derivative species, sugars, and lipid-derivative species.

Crucial correction of the Faix method for the determination of carbonyls in pyrolysis and hydrothermal liquefaction bio-oils with high nitrogen content

Accurate and reliable determination of carbonyl content in bio-oils from pyrolysis and hydrothermal liquefaction (HTL) of biomass is crucial not only for estimating the storage stability of the sample but also for creating an adequate design of the hydrotreatment process allowing long-term operation. The composition of bio-oils from various feedstocks can, however, significantly differ from woody bio-oils, which were utilized to develop the Faix method, the most frequently used for carbonyl determination. In this study, we present a limitation of this method when used for the analysis of bio-oils prepared from protein-rich biomass. These bio-oils are known to have a high nitrogen content, which can be present in the form of possibly interfering compounds. In this study, nitrogen interferences were identified, and a correction step mitigating the underestimation of carbonyl content was introduced. This novel approach was tested for 13 crude bio-oils prepared by pyrolysis or HTL from 10 different feedstocks with a wide range of nitrogen content. Besides crude bio-oils, five hydrotreated HTL oils from sewage sludge were also analyzed. For bio-oils or hydrotreated products with increased nitrogen content but containing less than 0.5 mmol/g of carbonyls, without the correction step, the method can provide zero and in extreme cases even negative values. Statistical analysis of results showed that the introduction of the correction step can be crucial for bio-oils containing more than 2 wt% of nitrogen and especially hydrotreated bio-oils from protein-rich biomass.

Chemical looping pyrolysis-gasification staged conversion of microalgae biomass with Ca-Fe composite oxygen carrier

Chemical looping pyrolysis-gasification staged conversion (CL-PGSC) of biomass was proposed in this work, which involves the separation of chemical looping gasification into two stages: biomass pyrolysis stage and bio-char gasification stage at different temperature. Pyrolysis and gasification behavior of Nannochloropsis sp., a microalga, with Ca-Fe composite oxygen carrier was investigated in a tubular reactor at varying temperatures and Ca-Fe molar ratios. The results indicate that all Ca-Fe composite oxygen carriers are capable of catalytically upgrading the quality of bio-oils in-situ during the pyrolysis stage. The complex metal oxides calcium ferrites facilitate the formation of aromatics and ketones, while both Fe2O3 and CaO components promote the production of alcohols. As for oxygen carrier with Ca-Fe molar ratio 1:1, the total peak area percentage of hydrocarbons and ketones reaches 66.5 area% within bio-oils, with 28.7 area% being toluene and 18.8 area% being 2-heptadecanone. Moreover, at the gasification stage, clean CO-rich or H2-rich syngas were generated from bio-chars produced at various pyrolysis temperatures with or without steam as a gasifying agent. In the proposed CL-PGSC process, Ca-Fe composite oxygen carrier serves as a catalysis for in-situ upgrading pyrolytic bio-oils, then as an oxygen donor for the gasification of pyrolytic char to achieve the simultaneous production of valuable pyrolytic bio-oils and clean syngas free from tar contamination. This provides a promising strategy for the full utilization of biomass.

Catalytic upgrading of intermediate pyrolysis bio-oil to hydrocarbon-rich liquid biofuel via a novel two-stage solvent-assisted process

A novel two-stage solvent-assisted batch catalytic hydroprocessing method has been developed for upgrading intermediate pyrolysis bio-oil to produce blended liquid fuels with ≈23 wt% hydrocarbon-rich biofuel content. Stage I reactions (160 °C for 3 h, then 300 °C for 3 h) involving mixtures of dodecane and bio-oil (mass ratio = 3:2), hydrogen gas and 5 wt%-metal supported catalysts (Pd/C, Pt/Al2O3 Pd/Al2O3, Ru/Al2O3) suppressed char formation. Up to 80 wt% liquid organic products were obtained, with the biofuel component dominated by ketones and phenols. Significant amounts of water and gas (mainly CO2) were also produced. Stage II reactions (300 °C for 3 h; 5 wt% Pt/Al2O3; hydrogen gas) with Stage I organic liquid products gave >90 wt% of blended liquid fuel. Overall, up to 96 wt% bio-oil deoxygenation and 53.4 wt% bio-carbon retention were achieved in the final organic liquid product via a combination of various reaction mechanisms. Pt/Al2O3 catalyst deactivated via hydrolysis of alumina and coking in stage I but remained stable during Stage II.

Role of in situ (in contact with biomass) and ex situ (in contact with pyrolysis vapors) transition metal catalysts on pyrolysis of cherry pits

While energy dense liquid biofuels can be produced from sustainable waste feedstocks via thermochemical conversion techniques, these biofuels are plagued by high acidity and low stability, largely due to the presence of oxygenated functional groups. By utilizing transition metal catalysts during pyrolysis either in situ within the biomass, or ex situ (directly downstream supported on an alumina substrate) acting on the pyrolysis vapors, the quality of the bio-oil can be improved via deoxygenation. Four transition metals (Cu, Mn, Ni, Zn) were either wet impregnated on cherry pit biomass, or were impregnated on alumina wool fibers placed downstream of the biomass to act on the devolatilized gases. The in situ catalysts Cu, Mn and Zn increase the pyrolysis bio-oil yield. The Mn, Ni and Zn used as ex situ catalysts increase the total non-condensable gas produced, suggesting that these downstream catalysts crack the pyrolyzed molecules into smaller organics and water. The ex situ catalysts result in larger quantities of especially oxygen-containing gases like CO2, which in turn lowered the bio-oil’s O/C ratio. However, such reactions also increase the water content of the resulting bio-oil. Both Mn and Zn used in either location enhance the concentration of alcohols relative to aromatic carbons, and when used ex situ, Mn shows a decrease in the ratio of aromatic to aliphatic carbon content.

Anthrone method combined with adsorption of interferents as a new approach towards reliable quantification of total carbohydrate content in pyrolysis bio-oils

Carbohydrates are a group of compounds abundantly present in pyrolysis bio-oils. Their quantitative analysis however presents many challenges such as possible co-elution with other oxygenates when liquid chromatographic methods are used. For a cheaper and faster analysis, spectrophotometric methods are a convenient alternative. Most of the absorption spectrometry-based methods stem from the reaction scheme, where the carbohydrates are converted into furfural or 5-hydroxymethylfurfural (HMF) derivatives and simultaneously react with colorizing agents such as phenol or anthrone. Alternatively, the produced compounds can be determined in the UV region without the addition of colorizing agent. An obvious problem arises when these furanic compounds are already present in the mixture, which is the case with most biomass-based pyrolysis bio-oils. In this study, we quantified the responses of 26 potential interferents that are expected to be present in the water-soluble fraction of bio-oils as well as 13 different carbohydrates. To mitigate the interferences, we used styrene-divinylbenzene polymeric resin adsorbents to separate the less polar interferents from the aqueous bio-oil extract and naturally formed bio-oil aqueous phases. A derivatization-GC-MS method was used as a reference for comparison of the results. We found that the adsorption step is crucial for acquiring more precise and accurate results. The anthrone method was the least susceptible to interferences and simultaneously produced results that were the closest to the reference GC-MS method. Statistical analysis showed no significant differences between the optimized anthrone method and the reference GC-MS method.

Sustainable biofuel production via catalytic hydrodeoxygenation of 4-methylanisole over Mo/nano γ-Al2O3

Recently, valorization of lignin biomass derived pyrolysis bio-oil for production of a sustainable fuel has turned to be a vital concern. Hydrodeoxygenation (HDO) has turned to be the most suitable developing process for production of a fuel with high heating value. In the current study, the HDO of 4-methylanisole as a model compound of pyrolysis oil, is investigated over Mo/nano γ-Al2O3 catalyst at a wide range of operating conditions. 4-methylanisole mainly follows hydrogenolysis and direct HDO to produce 4-methylphenol and toluene, respectively. Increasing operating temperature (623–773 K) and inverse weight hourly space velocity (WHSV−1: 0.008–0.333 g cat× h/g 4-methylanisole) lead in promoting toluene production. However, 4-methylphenol production and alkylation reactions are favored at high pressures (12–20 bar). 4-methylanisole conversion through HDO is 98% at 12 bar, 623 K and WHSV−1 of 0.333 g cat× h/g 4-methylanisole. The selectivity of toluene and 4-methylphenol production at the mentioned conditions is 0.44 and 0.17, respectively. It is inferred that hydrogenation, hydrogenolysis of Caliphatic—O, dehydration, deoxygenation of Caromatic—O, alkylation and tautomerization are the main reaction pathways during upgrading process which influence the selectivity of the products.