Upgrading Of Fast Pyrolysis Bio-oil Research Articles

Comparative Production of Bio-Oil from In Situ Catalytic Upgrading of Fast Pyrolysis of Lignocellulosic Biomass

Catalytic upgrading of fast pyrolysis bio-oil from two different types of lignocellulosic biomass was conducted using an H-ZSM-5 catalyst at different temperatures. A fixed-bed pyrolysis reactor has been used to perform in situ catalytic pyrolysis experiments at temperatures of 673, 773, and 873 K, where the catalyst (H-ZSM-5) has been mixed with wood chips or lignin, and the pyrolysis and upgrading processes have been performed simultaneously. The fractionation method has been employed to determine the chemical composition of bio-oil samples after catalytic pyrolysis experiments by gas chromatography with mass spectroscopy (GCMS). Other characterization techniques, e.g., water content, viscosity, elemental analysis, pH, and bomb calorimetry have been used, and the obtained results have been compared with the non-catalytic pyrolysis method. The highest bio-oil yield has been reported for bio-oil obtained from softwood at 873 K for both non-catalytic and catalytic bio-oil samples. The results indicate that the main effect of H-ZSM-5 has been observed on the amount of water and oxygen for all bio-oil samples at three different temperatures, where a significant reduction has been achieved compared to non-catalytic bio-oil samples. In addition, a significant viscosity reduction has been reported compared to non-catalytic bio-oil samples, and less viscous bio-oil samples have been produced by catalytic pyrolysis. Furthermore, the obtained results show that the heating values have been increased for upgraded bio-oil samples compared to non-catalytic bio-oil samples. The GCMS analysis of the catalytic bio-oil samples (H-ZSM-5) indicates that toluene and methanol have shown very similar behavior in extracting bio-oil samples in contrast to non-catalytic experiments. However, methanol performed better for extracting chemicals at a higher temperature.

Production of upgraded fuel blend from fast pyrolysis bio-oil and organic solvent using a novel three-stage catalytic process and its combustion characteristics in a diesel engine

An interdisciplinary approach involving the production and engine testing of a fuel blend containing upgraded bio-oil and fossil-derived solvent has been investigated in this present study. First, a novel 3-stage process of solvent-assisted catalytic upgrading of fast pyrolysis bio-oil was used to obtain a fuel blend with nearly 18 vol% biofuel content. Upgrading reactions were carried out between 160 °C and 300 °C, with 10 bar hydrogen gas, using 5 wt% Pt/Al203 catalyst for each of the three stages, with the main conversion reactions occurring in the first stage. The upgrading process produced 21.8 wt% of hydrocarbon-rich biofuel on bio-oil basis, achieving a high degree of deoxygenation with only 0.19 wt% oxygen in the final product. This was followed by the study of its combustion and emission characteristics in a 3-cylinder diesel engine, using a 10 vol% biofuel content in kerosene. All relevant testing regimes for liquid fuels were carried out, with its combustion and emission characteristics showing superior or similar results to those of conventions kerosene and diesel. The tested biofuel blend showed 2 % increments in engine performance. Overall, this work represents a significant advancement in the production of green liquid hydrocarbon-rich fuels for transport and domestic uses.

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.

Fractional Composition Analysis for Upgrading of Fast Pyrolysis Bio-Oil Produced from Sawdust

We can prevent climate change by reducing greenhouse gas (GHG) emissions caused by fossil fuel usage through introducing alternative fuels such as bio-oil. The fast pyrolysis process used for wood materials has recently gained substantial attention as an approach to produce bio-oil worldwide and in Korea as well. Bio-oil from fast pyrolysis contains highly oxygenated compounds and phenolics, thereby requiring upgrading processes, such as deoxygenation and condensation, for high-end use. To determine an efficient upgrading method for fast pyrolysis bio-oil (FPBO), one needs to elucidate its composition and classify it into chemical groups. We analyzed the composition of fractionized FPBO toward high-end use. FPBO was separated into two layers by adding distilled water: (a) the water-soluble phase, and (b) the oil phase, whereas liquid-liquid extraction and multi-step separation were applied for fractionization, respectively. The fractions were obtained, and their chemical groups were analyzed by gas chromatography time-of-flight mass spectrometry (GC×GC-TOF/MS). The water phase was separated into two fractions and classified into the main chemical groups of phenolics (9%) and heterocyclics (31%). The oil phase, which was separated into four fractions, was classified into the main chemical groups of phenolics (32%) and heterocyclics (23%). Our findings can help to upgrade products for high-end use.

Kinetic study of carbonaceous deposit formation and catalyst deactivation in hydrotreating of fast pyrolysis bio-oil

Fast pyrolysis of biomass followed by hydrotreating of bio-oil is considered to be a promising thermochemical conversion process of biomass to liquid fuel. Catalytic hydrotreating converts the crude bio-oil from biomass pyrolysis into liquid intermediates with reduced oxygen content, and low viscosity and acidity. However, effective lifetime of catalyst can be significantly reduced by coking which has been recognized as the main cause of catalyst deactivation during the hydrotreating process. In this study, similar phenomenon has been observed but the catalyst deposit was different from the reported coke and thus a new term of carbonaceous deposit is introduced. Kinetics of the carbonaceous deposit formation and its characteristics have been investigated for hydrotreating of bio-oil derived from fast pyrolysis of rice husk using commercial HTB-45 Ni-based catalyst. A mathematical model for the hydrotreating process, which is based on key chemical reactions and consists of ordinary differential equations (ODEs), has been developed and solved with the kinetic parameters being obtained from the experiments. Results of this study are helpful for better understanding and optimization of the catalytic upgrading of fast pyrolysis bio-oil.

Production of renewable fuels by blending bio-oil with alcohols and upgrading under supercritical conditions

The work studied a non-catalytic upgrading of fast pyrolysis bio-oil by blending under supercritical conditions using methanol, ethanol and isopropanol as solvent and hydrogen donor. Characterisation of the bio-oil and the upgraded bio-oils was carried out including moisture content, elemental content, pH, heating value, gas chromatography-mass spectrometry (GCMS), Fourier transform infrared radiation, 13C nuclear magnetic resonance spectroscopy, and thermogravimetric analysis to evaluate the effects of blending and supercritical reactions. The GCMS analysis indicated that the supercritical methanol reaction removed the acids in the bio-oil consequently the pH increased from 2.39 in the crude bio-oil to 4.04 after the supercritical methanol reaction. The ester contents increased by 87.49% after the supercritical methanol reaction indicating ester formation could be the major deacidification mechanism for reducing the acidity of the bio-oil and improving its pH value. Simply blending crude bio-oil with isopropanol was effective in increasing the C and H content, reducing the O content and increasing the heating value to 27.55 from 17.51 MJ·kg−1 in the crude bio-oil. After the supercritical isopropanol reaction, the heating value of the liquid product slightly further increased to 28.85 MJ·kg−1.

Upgrading of fast pyrolysis bio-oil to drop-in fuel over Ru catalysts

Catalyst plays a key role in the upgrading of fast pyrolysis bio-oil to advanced drop-in fuel, while the selectivity and deactivation of catalyst still remain the biggest challenge. In this study, three Ru catalysts with activated carbon, Al2O3 and ZSM-5 as supports were prepared and tested in bio-oil hydrotreating process. The physical properties and components of upgraded bio-oil were detected to identify the difference in catalytic performance of three catalysts. The results showed that furan, phenols and their derivatives in fast pyrolysis bio-oil could be hydrogenated to alkanes, alkenes and benzenes over Ru catalysts. The different components of oil phase over three catalysts may be resulted from the surface properties of three supports. Activated carbon supported Ru catalyst showed the best catalytic performance and was suggested to be the most promising catalyst for pyrolysis bio-oil upgrading.

Impact of Macroporosity on Catalytic Upgrading of Fast Pyrolysis Bio-Oil by Esterification over Silica Sulfonic Acids.

Fast pyrolysis bio‐oils possess unfavorable physicochemical properties and poor stability, in large part, owing to the presence of carboxylic acids, which hinders their use as biofuels. Catalytic esterification offers an atom‐ and energy‐efficient route to upgrade pyrolysis bio‐oils. Propyl sulfonic acid (PrSO3H) silicas are active for carboxylic acid esterification but suffer mass‐transport limitations for bulky substrates. The incorporation of macropores (200 nm) enhances the activity of mesoporous SBA‐15 architectures (post‐functionalized by hydrothermal saline‐promoted grafting) for the esterification of linear carboxylic acids, with the magnitude of the turnover frequency (TOF) enhancement increasing with carboxylic acid chain length from 5 % (C3) to 110 % (C12). Macroporous–mesoporous PrSO3H/SBA‐15 also provides a two‐fold TOF enhancement over its mesoporous analogue for the esterification of a real, thermal fast‐pyrolysis bio‐oil derived from woodchips. The total acid number was reduced by 57 %, as determined by GC×GC–time‐of‐flight mass spectrometry (GC×GC–ToFMS), which indicated ester and ether formation accompanying the loss of acid, phenolic, aldehyde, and ketone components.

Upgrading of fast pyrolysis bio-oil over Fe modified ZSM-5 catalyst to enhance the formation of phenolic compounds

The present study is aimed to investigate the upgrading of beech sawdust pyrolysis bio-oil through catalytic cracking of its vapors over Fe-modified ZSM-5 zeolite in a fixed bed tubular reactor. The zeolite supported iron catalyst was successfully prepared with varying metal loading ratios (1, 5, 10 wt%) via dry impregnation method and further characterized by BET, XRD, and SEM-EDX techniques. TG/FT-IR/MS analysis was used for the detection of biomass thermal degradation. Product yields of non-catalytic and catalytic pyrolysis experiments were determined and the obtained results show that bio-oil yields decreased in the presence of catalysts. Besides, the bio-oil composition is characterized by GC/MS. It was indicated that the entity of the ZSM-5 and Fe/ZSM-5 catalyst reveal a significant enhancement quality of the pyrolysis products in comparison with non-catalytic experiment. The catalyst increased oxygen removal from the organic phase of bio-oil and further developed the production of desirable products such as phenolics and aromatic compounds.

Non-catalytic upgrading of fast pyrolysis bio-oil in supercritical ethanol and combustion behavior of the upgraded oil

Fast pyrolysis bio-oil derived from empty palm fruit bunch was upgraded in supercritical ethanol (scEtOH) without using external catalysts and molecular hydrogen. The effects of the reaction temperature and time on the product yield and the quality of the upgraded oil based on parameters like the elemental content, total acid number (TAN), water content, high heating value (HHV), and viscosity were examined. At 400°C, almost all of the organic species in the fast pyrolysis bio-oil were converted to the liquid and gas phase in 30min, resulting in a high yield of the upgraded oil (83.0wt%) with an enhanced HHV of 34.1MJkg−1 and very low values of TAN (4.8mgKOHg−1) and water (1.6wt%) when compared to the fast pyrolysis bio-oil (HHV, 24.3MJkg−1; TAN, 69.4mgKOHg−1; water, 14.0wt%). The major chemical species in the upgraded oil were alcohols, esters, phenols, hydrocarbons, and aromatics. After aging at 80°C for one week, a marginal increase in the viscosity of the upgraded bio-oil was observed, indicating a significant improvement in the stability of the bio-oil. Computational fluid dynamics (CFD) analysis of the process performed in a commercial boiler demonstrated that the upgraded oil firing exhibited high gas temperature profiles, a high firing peak of 1599°C, and a high total heat transfer rate of 121.81MWth. These results are comparable to the performance parameters of conventional heavy oil-firing processes.

Experimental study on bio-oil upgrading over [formula omitted] catalyst in supercritical ethanol

The effects of reaction conditions, including the initial hydrogen pressures (0.5MPa, 2.0MPa), the mass ratios of ethanol to bio-oil (5:1, 3:1, 2:1, 1:1) and reaction temperatures (260°C, 280°C, 300°C) on catalytic upgrading of fast pyrolysis bio-oil were investigated in this work. Experiments were carried out in supercritical ethanol with bifunctional 5%Pt/SO42-/ZrO2/SBA-15 catalyst. The physical properties and organic compounds of upgraded bio-oil were compared and the mass and energy balance of certain upgrading processes were studied. The results showed that higher initial hydrogen pressure (2.0MPa) could inhibit coke formation effectively. Increasing mass ratio of ethanol to bio-oil (5:1, 3:1) was helpful for desired products formation and heating value improvement as well as lower coke yield. With the rising temperature, the heating value of upgraded bio-oil increased, but the amount of desired products reduced and the formation of coke became much more serious.

Life cycle assessment of transportation fuels from biomass pyrolysis

This article evaluates the environmental performance of a biofuel production system based on the fast pyrolysis of short-rotation poplar biomass using a Life Cycle Assessment (LCA) approach. The system includes a circulating fluidized bed reactor followed by bio-oil upgrading through hydrotreating and hydrocracking to produce gasoline and diesel. The investigated system was selected on the basis of an overview of available technologies for the production and upgrading of fast pyrolysis bio-oil.Inventory data for the whole system were collected and used in order to carry out the life cycle impact assessment. Seven impact categories were evaluated: cumulative energy demand, global warming, ozone layer depletion, photochemical oxidant formation, land competition, acidification and eutrophication. Feedstock pre-treatment, pyrolysis and steam reforming for the production of the hydrogen required for hydroprocessing were identified as the subsystems with the highest contributions to the potential impacts. Within these subsystems, natural gas production, electricity generation and direct emissions to air were the main contributors. Special attention should also be paid to the production of the lignocellulosic biomass feedstock, especially to the associated land occupation and fertilizer requirements.

One-Step Hydrogenation−Esterification of Aldehyde and Acid to Ester over Bifunctional Pt Catalysts: A Model Reaction as Novel Route for Catalytic Upgrading of Fast Pyrolysis Bio-Oil

The bio-oil from fast pyrolysis of biomass cannot be used effectively as engine fuel because of its high corrosiveness and instability mainly due to substantial amounts of organic acids and reactive aldehydes. In this paper a treatment of acids and aldehydes in the bio-oil was focused on. A novel upgrading method named one-step hydrogenation−esterification (OHE) was established to convert acids and aldehydes to stable and combustible components. Acetaldehyde (butyl aldehyde) and acetic acid were chosen as model compounds for the OHE reaction over platinum catalysts that acidic supports such as HZSM-5 or amorphous aluminum silicate were adopted. The catalysts were bifunctional, which means they have properties of hydrogenation and esterification. Experiments showed this, and it was a feasible route to convert these main unstable components of bio-oil to esters through this simple and effective OHE reaction. The catalysts with high surface area, large pore size distribution, small metal particles,and strong...