Pyrolysis Bio-oil Research Articles

Evaluation of the Catalytic Deoxygenation Process of Pyrolytic Bio Oil Using Carbon Supported Ruthenium Catalyst

Evaluation of the Catalytic Deoxygenation Process of Pyrolytic Bio Oil Using Carbon Supported Ruthenium Catalyst

Effect of Carboxylic Acids on Corrosion of Type 410 Stainless Steel in Pyrolysis Bio-Oil

Biomass-derived oils are renewable fuel sources and commodity products and are proposed to partially or entirely replace fossil fuels in sectors generally considered difficult to decarbonize such as aviation and maritime propulsion. Bio-oils contain a range of organic compounds with varying functional groups which can lead to polarity-driven phase separation and corrosion of containment materials during processing and storage. Polar compounds, such as organic acids and other oxygenates, are abundant in bio-oils and are considered corrosive to structural alloys, particularly to those with a low-Cr content. To study the corrosion effects of small carboxylic acids present in pyrolysis bio-oils, type 410 stainless steel (SS410) specimens were exposed in bio-oils with varying formic, acetic, propionic and hexanoic acid contents at 50 °C during 48 h exposures. The specific mass change data show a linear increase in mass loss with increasing formic acid concentration. Interestingly, a mild corrosion inhibition effect on the corrosion of SS410 specimens was observed with the addition of acetic, propionic and hexanoic acids in the bio-oil.

Aqueous-phase reforming of water-soluble compounds from pyrolysis bio-oils

Aqueous-phase reforming (APR) of model compounds of bio-oil aqueous fraction (AFB) was studied at different operating conditions. Substrate conversion, carbon-to-gas yield (CCgas) and hydrogen and alkanes production were evaluated. Levoglucosan, hydroxyacetone, furfural and acetic acid were selected as representative of AFB and tested in batch APR at different concentrations (1–5 %wt.), temperatures (175–220 °C) and reaction times (0.5–4 h), using 3% (wt.) Pt/CB catalysts. Best results were obtained at 220 °C and 1%, with 70–90% substrate conversions, 45–70% CC gas and hydrogen production up to 50 mmol per gram of total organic carbon (TOC). Catalyst stability was checked in APR of levoglucosan during five successive 4 h reaction cycles. The catalyst exhibited high stability, CCgas remained constant and hydrogen production increased and became stable after first reaction cycle with only a slight decrease of TOC conversion. The catalyst with well dispersed metal phase and high contribution of nanoparticles smaller than 2 nm showed a higher production of hydrogen. APR was proved to be a feasible option for the valorisation of AFB.

Valorization of Eucalyptus, Giant Reed Arundo, Fiber Sorghum, and Sugarcane Bagasse via Fast Pyrolysis and Subsequent Bio-Oil Gasification.

Fast pyrolysis of giant reed Arundo (Arundo donax), fiber sorghum (Sorghum bicolor L.Moench), eucalyptus (Eucalyptus spp.), and sugarcane bagasse (Saccharum officinarum) was studied in bench-scale bubbling fluidized bed reactor. Product yields were determined, and detailed physicochemical characterization for produced fast pyrolysis bio-oils (FPBOs) was carried out. The highest organic liquid yield (dry basis) was observed with sugarcane bagasse (59–62 wt %), followed by eucalyptus (49–53 wt %), giant reed Arundo (39 wt %), and fiber sorghum (34–42 wt %). After the pyrolysis experiments, produced FPBOs were gasified in an oxygen-blown autothermal catalytic reforming system for the produced synthesis gas. The gasifier consists of a partial oxidation zone where the FPBO is gasified, and the raw syngas is then reformed over a fixed bed steam-reforming catalyst in the reforming zone. The gas production (∼1.7 Nm3/kg FPBO) and composition (H2 ∼ 50 vol %, CO 20–25 vol %, and CO2 25–30 vol %) were similar for all FPBOs tested. These results show that the combination of fast pyrolysis with subsequent gasification provides a technically feasible and feedstock flexible solution for the production of synthesis gas.

Contribution of atmospheric pressure chemical ionization mass spectrometry for the characterization of bio-oils from lignocellulosic biomass: Comparison with electrospray ionization and atmospheric pressure photoionization

Bio-oils obtained from lignocellulosic biomass pyrolysis present a very promising alternative to replace petroleum-based fuels. At the molecular level, these materials are highly complex organic mixtures comprising thousands of species covering a large range of mass and polarity. Compared to petroleum, they present a high amount of oxygen containing compounds, limiting their direct use in the classical refining system. To understand and improve both the conversion and upgrading processes, an advanced molecular description of the raw and upgraded bio-oils is required. The most powerful technique for the molecular characterization of such sample is Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS), thanks to its very high mass accuracy and resolving power. It allows assigning unambiguously a unique molecular formula to each m/z signal. Besides, the use of different ionization sources ensures an extensive molecular description and enables to assess the efficiency of different catalytic chemical treatments. In this study, we report the characterization of a pine pyrolysis bio-oil by the three main atmospheric pressure ionization sources: electrospray (ESI), atmospheric pressure photoionization (APPI) and atmospheric pressure chemical ionization (APCI) in positive mode coupled to FTICR analyzer. In addition, different solvents and dopants were used to ensure a comprehensive description of the molecular content. Regardless of the atmospheric pressure ionization sources used, C0–100H0–300O0–15 molecular formulas are mainly obtained with lignocellulosic biomass-based bio-oils. Nevertheless, depending on the ionization source, the ions relative intensity are significantly different in respect with their double bound equivalent (DBE), oxygen to carbon ratio (O/C) and hydrogen to carbon ratio (H/C). For example, the APPI source has shown the efficient ionization of aromatic (high DBE and low H/C) less polar (low O/C) molecules compared to the ESI source which efficiency ionized more polar species with high oxygen atom content (high O/C). APCI source has proven to be particularly useful for bio-oil characterization as it demonstrates the presence of an aliphatic distribution in addition to the other bio-oil components also ionized by APPI and ESI.

Promotion of biomass pyrolytic saccharification and lignin depolymerization via nucleophilic reagents quenching of the carbonium ions

The condensation of lignin under acidic conditions inhibited the subsequent value-added utilization of lignin, and the condensed lignin covered the biomass surface. Here, a method of benzenesulfonic acid pretreatment combined with nucleophilic reagents promoted pyrolytic saccharification and lignin hydrogenation was reported. The anhydrosugar content in the pyrolysis bio-oil increased from 66.91% to 69.00%, 72.88%, and 72.16% via adding methanol, propionaldehyde, 3-hydroxylic-2-naphthoic acid, respectively. The characterization of the biomass surface structure and the calculation of bond lengths indicated that carbonium ions prefer to bind with the added nucleophilic reagent rather than the lignin fragment. Furthermore, the quenching of the carbonium ions preserved the β-O-4 bond, as demonstrated in 2D NMR. In the subsequent hydrogenation reaction, it was found that methanol facilitated the production of lignin monomer. The calculation also revealed that the quenching of the carbonium ions with methanol reduced the bond-breaking energy of the β-O-4 bond.

Pyrolysis of Biosolids to Produce Biochars: A Review

The continuing increase in population means an increasing demand for products and services, resulting in huge amounts of waste being discharged into the environment. Therefore, waste management requires the application of new and innovative solutions. One new approach involves converting waste into value-added chemicals and products for use directly or after further processing into higher value-added products. These processes include biological, thermochemical, and physiochemical methods. Furthermore, biosolids, including treated sewage sludge (SS), represent one of the major by-products of human activities, constituting a major environmental hazard and requiring the treatment of contaminated wastewater with associated health hazards. Sustainable solutions to manage and dispose of this type of waste are required. In this review, pyrolysis, a thermochemical conversion technology, is explored to convert biosolids to biochars. The review addresses previous studies, by providing a critical discussion on the present status of biosolids processing, the potential for energy recovery from the pyrolysis bio-oil and biogas, and finally some benefits of the production of biochars from biosolids.

Derivatizing of Fast Pyrolysis Bio-Oil and Coprocessing in Fixed Bed Hydrotreater

In several countries forest-based biofuels are being developed and to some extent also deployed. Fast pyrolysis bio-oil produced from, for example, sawdust, has now been coprocessed in fluid catalytic cracking refinery units in a number of commercial trials. However, this application is limited to about 10% of the total feed, and coprocessing in conventional fixed bed hydrotreaters is necessary to reach the high potential with this feedstock. Feeding and upgrading of fast pyrolysis bio-oil in a fixed bed reactor configuration is still problematic due to the inherent bio-oil properties. Stabilization of reactive compounds in fast pyrolysis bio-oil and mild hydrotreatment in a separate refining unit prior to refinery integration has therefore been developed the past decade. Another approach, presented here, involves complete dewatering of fast pyrolysis bio-oil by azeotropic distillation using mesityl oxide as the solvent, followed by conversion of the abundant hydroxyl compounds via mixed anhydride esterification methodology using an external source of mixed carboxylic acids of different chain lengths originating from renewable tall oil fatty acids, providing a lipophilic feed component. Dewatering and derivatizing were carried out in reactors up to 50 dm3 with a mass ratio of fast pyrolysis bio-oil to tall oil fatty acid of 10:13. The produced lipophilic oils were miscible with a petroleum light gas oil fraction and exhibited superior stability even after accelerated aging at elevated temperature (80 °C). The derivatized oils were thus mixed with light gas oil, with a proportion of 30 wt % derivatized oil in final blends and hydrotreated continuously in pilot fixed bed reactors for 14 days at 4 operating conditions without plugging or excessive exotherms. The test conditions were varied; the reactor pressure was either 55 or 80 bar, temperature 380 or 400 °C, and liquid hourly space velocity either 1 or 2 h–1 during the hydrotreatment. Successful hydrodeoxygenation and desulfurization were accomplished, whereas an increasing nitrogen concentration could be observed in the liquid products with the particular catalyst and reaction conditions employed. The observed hydrogen consumption (15–20 g/kg feed) was compared with the stoichiometric consumption for direct deoxygenation and with typical consumptions for industrial hydrotreated vegetable oil processing. The measured biogenic carbon content in hydrotreated liquid products (26.7%) agreed extremely well with the calculated biogenic carbon content in the hydrotreating feed (26.6%) that consisted of the blend of derivatized oil and petroleum light gas oil. The overall results are very promising since simple unit operations can be used to produce derivatized fast pyrolysis bio-oils that do not need additional standalone hydrotreating units but can be coprocessed in existing ones.

Evolution of Stable Free Radicals during Bio-Oil Pyrolysis and Its Relation to Coke Formation: An in Situ EPR Study

Evolution of Stable Free Radicals during Bio-Oil Pyrolysis and Its Relation to Coke Formation: An in Situ EPR Study

Experimental and kinetic model studies on the pyrolysis of 2-furfuryl alcohol at two reactors: Flow reactor and jet-stirred reactor

2-Furfuryl alcohol, derived from non-edible biomass, is the significant component of bio-oil in the pyrolysis of lignocellulose biomass and a potential alternative fuel or fuel additive. To better optimize the pyrolysis model of lignocellulose to improve the properties of pyrolysis bio-oil and further understand the combustion characteristics of 2-furfuryl alcohol, the pyrolysis experiments were performed in a flow reactor at 30 Torr for T = 1006 – 1339 K and 760 Torr for T = 850 – 1131 K, and in a jet-stirred reactor at 760 Torr for T = 750 – 1050 K. The pyrolysis products, including radicals (methyl, propargyl, allyl, and cyclopentadienyl), isomers (furfural/2-ethyl furan, furan/vinyl ketene, and allene/propyne), and aromatics (benzene, toluene, indene, etc.) were identified and measured using synchrotron vacuum ultraviolet photoionization mass spectrometry. A comprehensive kinetic model for 2-furfuryl alcohol pyrolysis was developed and was validated against the experimental data in the present and previous work. Rate of production analysis indicated that the C–O bond dissociation reaction, H-abstraction reactions on the hydroxymethyl group, and the H-addition reactions on the furan-ring controlled the consumption of 2-furfuryl alcohol and the formation of primary pyrolysis products like 2-methyl furan, 2-ethyl furan, furfural, and furan. In addition, the OH-addition reaction on the furan-ring had a certain contribution to the consumption of 2-furfuryl alcohol, while the contribution of H-shift reactions was negligible. The present work systematically compared the effects of methyl, ethyl, and hydroxymethyl groups on the decomposition of furanic fuels and the formation of major products. The results showed that the substituent groups can reduce the decomposition temperature of the fuels, especially the ethyl and hydroxymethyl groups. The alkyl substituent group can promote the formation of small hydrocarbons, of which the mole fraction increased with the length of the carbon chain increasing. The hydroxymethyl group facilitated the formation of oxygenated products.

Valorization of sludge using microwave pyrolysis for green bio-energy: Combined effects of key parameters on the directional optimization of high-quality syngas

To directionally convert sludge into the high-quality syngas, the effects of various parameters on the biogas produced by the sludge microwave pyrolysis are explored, and the syngas generation mechanism under the synergistic effect of parameters is revealed. The results showed that the pyrolysis final temperature, reaction time, and the amount of the microwave absorber were the key factors that affected the biogas yield. A response surface analysis was used to explore the synergistic effect of each key parameter on the yield and the lower heating vale (LHV) of syngas. The pyrolysis temperature was the key to driving syngas generation. Properly prolonging the reaction time decreased the formation of tar by-products and increased the syngas yield. The addition of a microwave absorber increased the heating rate by enhancing the conversion efficiency of microwave energy, and this contributed to accelerating the dehydrogenation and the Boudouard reactions to promote the generation of H2 and CO. Under high temperature conditions (900 °C), a higher syngas yield (10.25–34.31 mol/kgDS) and LHV (4.85–14.53 MJ/kgDS) were obtained in a shorter period time by synergistically optimizing the amount of microwave absorbers (8–10 g) and the reaction time (28–40 min). As the pyrolysis temperature increased, the H2 content gradually rose to the peak, while the content of CO continued to increase. By analyzing the evolution of the specific pyrolysis products, the secondary pyrolysis of bio-oil at high temperatures and the Boudouard reaction were found to be the primary pathways that promoted syngas generation. This research provides strategic guidance for producing high-quality syngas using the microwave pyrolysis of waste biomass, thereby minimizing the exploration cost of basic experiments and providing directional control of the syngas quality.

Fast pyrolysis characteristics and its mechanism of corn stover over iron oxide via quick infrared heating

The harm done to the environment by fossil fuels was serious, and it is urgent to find effective methods and adopt carbon–neutral feedstock to prevent further environmental damage. An innovative infrared heating reactor was developed for the generation of high-yield bio-oil and cleaner pyrolysis gases. This work was devoted to exploring the fast pyrolysis characteristics and its mechanism of corn stover over the iron oxide in a novel infrared heating (IH) reactor and a traditional electric heating (EH) reactor. In the IH reactor, the bio-oil yield increased initially and then decreased with increasing pyrolysis temperature, reaching a maximum yield of 29 wt% at 600 °C. The yield of pyrolysis bio-oil and water decreased as the reusability number rose, whereas the char yield increased. Bio-oil yields decreased less from R0 to R3 and the catalyst was more effective in IH. IH produced more char and gas but considerably less water than EH, and its bio-oil had fewer phenols. Raman spectroscopy demonstrated that the aromatic structure of biochar increased as the pyrolysis temperature increased. Cellulose and hemicellulose can be completely cleaved at lower temperatures in IH. In addition, Fe2O3 catalysts have shown the advantages of low cost, efficient cycling, and long action time. Infrared heating coupled with iron oxide catalyst shows the potential to increase bio-oil yield and is more promising for industrial production than EH.

Recent progress in the catalytic thermochemical conversion process of biomass for biofuels

This review paper introduces various biomasses (e.g., agricultural, woody biomass waste) used in thermochemical conversion processes, including gasification, pyrolysis, and hydrothermal liquefaction. The recent advances and progress in catalytic thermochemical conversion technologies are analyzed. In particular, the role of catalysts in different reactors on the major products (bio-oil and syngas) is discussed with respect to the product yield and property. Various catalytic reaction mechanisms during the thermochemical conversion reaction are discussed to explain the conditions to enhance the desired pyrolysis product quality. Furthermore, different types of reactors for each thermochemical process are reviewed. Further processing technologies using biomass pyrolytic bio-oil products are also introduced. Finally, this review paper presents the related challenges and opportunities encountered in thermochemical conversion processes to understand better the future of thermochemical conversion processes in biorefineries.

Estimation of fast pyrolysis bio‐oil properties from feedstock characteristics using rough‐set ‐based machine learning

In this work, a data-driven rough-set-based machine learning model has been proposed as a pre-processing and predictive modelling tool to predict the pyrolysis bio-oil properties based on pyrolysis temperature and feedstock characteristics. A database consisting of feedstock proximate and ultimate analyses, pyrolysis temperature, bio-oil's pH value, and bio-oil's higher heating value was compiled and used to train the rough-set-based machine learning model. The resulting rule-based rough-set-based machine learning model demonstrated promising strength, certainty, and coverage factor. Furthermore, the emergent patterns and mechanistic plausibility of the rough-set-based machine learning models were analysed. The generated rules illustrated reasonable predictive capability in estimating the higher heating value and pH value of bio-oil based on the feedstock characterisation and pyrolysis temperature. Rough-set-based machine learning model is thus demonstrated to be a simple and straightforward approach for feedstock composition and pyrolysis temperature selection in pyrolysis/co-pyrolysis bio-oil production.

The effect of temperature distillation on products distribution derived from wood pyrolysis bio-oil

Bio-oil from biomass pyrolysis can be converted to chemicals, solid carbon materials, and syngas by various thermochemical conversion technology methods. Because of the elevated temperature, bio-oil suffers drastic component changes as the first step in these processes. Understanding the impact of heating temperature on bio-oil transformation during the distillation process is critical for practical bio-oil usage. A bio-oil feedstock produced from the pyrolysis of lamtoro wood residue at 500 °C was used in distillation from this work. Complete temperature range analysis of 96, 97, 98, 99, and 100 °C was conducted. Eight typical compounds in bio-oil were precisely quantified by gas chromatography-mass spectroscopy (GC-MS) and FTIR analysis. The results revealed that a common critical point was widely present during the distillation process, which may be attributed to a stable system generated by hydrogen bonding. As a result, the content of acetic acid, 2-Propanone, and phenol was up to 38%, 12%, and 20%, respectively. The detailed distillation characteristics and product distribution provide a comprehensive insight into the reaction process and component enrichment patterns, assisting design and parameter optimization.

Catalytic pyrolysis of holocellulose followed by integrated aldol condensation and hydrogenation to produce aviation fuel

The carbonyl platform compound from the catalytic pyrolysis of holocellulose was employed for the integrated aldol condensation and hydrogenation to produce hydrocarbons in the range of jet fuel. By the carbonylation of the pyrolysis vapor from holocellulose prepared from rape straw, bagasse and poplar (RS-Holo, BG-Holo and PL-Holo), it was revealed that BG-Holo rich in cellulose as the raw material presented the most production of carbonyl compounds including aldehydes and ketones. The optimal temperature for carbonylation of pyrolysis vapor from holocellulose was determined to be 400 °C, with the maximized carbon yield of carbonyls reaching 46.11%, which was boosted to the summit of 53.59% with more addition of ZrO2 catalyst. The integrated aldol condensation and hydrogenation were carried out using the catalytic pyrolysis bio-oil as the reactant over Ni/Mg-Al-O/AC bifunctional catalyst, with the highest carbon yield of hydrocarbons reaching 78.11%. The production mechanism of the final targeted alkanes was speculated, and it was discovered that ketones and aldehydes with short carbon chains are more prone to secondary condensation than those with long carbon chains, resulting in high-energy–density aviation fuel. Furthermore, the heating value of final oil was calculated based on an empirical formula, which was comparable to that of Jet A, meeting the standard of ASTM7566. The final oil’s distillation range distribution was simulated, and most of it fell in the range of aviation fuel. In this study, catalytic fast pyrolysis of holocellulose followed by integrated aldol condensation and hydrogenation was proved to be a promising way for producing aviation fuel.

Revealing the Reactivity of Individual Chemical Entities in Complex Mixtures: the Chemistry Behind Bio-Oil Upgrading.

Bio-oils are precursors for biofuels but are highly corrosive necessitating further upgrading. Furthermore, bio-oil samples are highly complex and represent a broad range of chemistries. They are complex mixtures not simply because of the large number of poly-oxygenated compounds but because each composition can comprise many isomers with multiple functional groups. The use of hyphenated ultrahigh-resolution mass spectrometry affords the ability to separate isomeric species of complex mixtures. Here, we present for the first time, the use of this powerful analytical technique combined with chemical reactivity to gain greater insights into the reactivity of the individual isomeric species of bio-oils. A pyrolysis bio-oils and its esterified bio-oil were analyzed using gas chromatography coupled to Fourier transform ion cyclotron resonance mass spectrometry, and in-house software (KairosMS) was used for fast comparison of the hyphenated data sets. The data revealed a total of 10,368 isomers in the pyrolysis bio-oil and an increase to 18,827 isomers after esterification conditions. Furthermore, the comparison of the isomeric distribution before and after esterification provide new light on the reactivities within these complex mixtures; these reactivities would be expected to correspond with carboxylic acid, aldehyde, and ketone functional groups. Using this approach, it was possible to reveal the increased chemical complexity of bio-oils after upgrading and target detection of valuable compounds within the bio-oils. The combination of chemical reactions alongside with in-depth molecular characterization opens a new window for the understanding of the chemistry and reactivity of complex mixtures.

Sustainable conversion of biomass to rationally designed lithium-ion battery graphite

The carbon net negative conversion of bio-char, the low value byproduct of pyrolysis bio-oil production from biomass, to high value, very high purity, highly crystalline flake graphite agglomerates with rationally designed shape and size tailored for lithium-ion battery energy storage material is reported. The process is highly efficient, 0.41 g/Wh; the energy content of its co-product of the process, bio-oil, exceeds that needed to power the process. It is shown that the shape of the starting material is retained during the transformation, allowing the ultimate morphology of the graphite agglomerates to be engineered from relatively malleable biomass. In contrast to commercial graphite production, the process can be performed at small scale with low equipment costs, enabling individual research laboratories to produce Li-ion grade graphite with customizable shape, size and porosity for Si/graphite composite and other graphite involved anodes. The mechanism of the graphitization of bio-char, a “non-graphitizable” carbon, is explored, suggesting the molten metal catalyst is absorbed into the pore structure, transported through and transforming the largely immobile biochar. Finally, the transformation of biomass to rationally designed graphite morphologies with Li-ion anode performance that closely mimic commercial shaped graphite is demonstrated.

Analysis of Lipophilic Extractives from Fast Pyrolysis Bio-Oils.

Fast pyrolysis bio-oils (FPBOs) originating from forest residues contain extractive-derived substances, which may form a separate, sticky layer with char particles on the surface of these bio-oils. In this study, first, the removal of extractive-derived substances from the bio-oil top phase was studied by common solvents with different polarities. In this case, the results indicated that when aimed at the maximum yield of single-phase fuel oil and thus the maximum amount of extractives removed, the use of n-heptane or n-hexane seems to be of benefit for this purpose. For safety reasons, the use of n-heptane was recommended. Second, an analysis practice (extraction time and the way of mixing) was optimized. In order to reduce the extraction time and enhance the extraction yield, it was important to break the oil surface in extraction. Third, based on the characterization results of the n-heptane extract by gas chromatography and ultraviolet spectroscopy, the detected compounds were classified as fatty acids, resin acids, esterified fatty acids, terpenoids, and steroids, and their total content (27 wt %) was lower than that of lignin-derived compounds (70 wt %). The extraction of the FPBO top phase with n-heptane followed by this analysis practice was a useful way to estimate the content and composition of lipophilic extractives.

Fractional Condensation of Fast Pyrolysis Bio-Oil to Improve Biocrude Quality towards Alternative Fuels Production

Fast pyrolysis of biomass is a well-known opportunity for sustainable alternative fuel production for transport and energy. However, bio-oils from biomass pyrolysis are viscous, acidic bio-crudes that need further steps of upgrading before being used either as fuels or chemicals. A process that is complementary to bio-oil hydrotreatment or co-processing consists of optimizing and tuning the upstream condensation steps of fast pyrolysis to separate and concentrate selected classes of compounds. This can be implemented by varying the condensation temperatures in a multi-step condensation unit. In this study, fractional condensation of fast pyrolysis vapors from pinewood has been applied to a bubbling fluidized bed reactor of 1 kg h−1 feed. The reactor was operated at 500 °C and connected to a downstream interchangeable condensation unit. Tests were performed using two different condensing layouts: (1) a series of two spray condensers and a tube-in-tube water-jacketed condenser, referred to as an intensive cooler; (2) an electrostatic precipitator and the intensive cooler. Using the first configuration, which is the focus of this study, high boiling point compounds—such as sugars and lignin-derived oligomers—were condensed at higher temperatures in the first stage (100–170 °C), while water-soluble lighter compounds and most of the water was condensed at lower temperatures and thus largely removed from the bio-oil. In the first two condensing stages, the bio-oil water content remained below 7% in mass (and therefore, the oil’s high calorific content reached 22 MJ kg−1) while achieving about 43% liquid yield, compared to 55% from the single-step condensation runs. Results were finally elaborated to perform a preliminary energy assessment of the whole system toward the potential upscaling of this fractional condensation approach. The proposed layout showed a significant potential for the upstream condensation step, simplifying the downstream upgrading stages for alternative fuel production from fast pyrolysis bio-oil.