Biomass Pyrolysis Oil Research Articles

Compositional Changes during Hydrodeoxygenation of Biomass Pyrolysis Oil

Hydrodeoxygenation (HDO) is usually considered as a promising process for upgrading biomass pyrolysis oil (PO) to bio-fuels. However, cognition of HDO is inhibited by the complexity of the PO and upgraded products. In this study, a PO and its upgraded pyrolysis oil (UPO) samples were analyzed by nuclear magnetic resonance, gas chromatography/mass spectrometry, and electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS). ESI FT-ICR MS revealed the most abundant compounds in PO were O2–O18 species with double bond equivalent (DBE) values of 0–22. After HDO, oxygen numbers gradually shifted to a range of O1–O10, and DBE number also progressively decreased. The major oxygen compounds such as carbonyls, carboxylic acids, ethers, carbohydrates, and alcohols were significantly changed with respect to relative content and molecular composition. Lignin polymers were depolymerized after reduction of the carbonyl and methoxy groups. For HDO, hydrogenation of carbonyls, car...

Stability mechanism investigation of emulsion fuels from biomass pyrolysis oil and diesel

In this paper, emulsion fuels from crude bio-oil and its molecular distillation fractions were prepared by single ultrasonic and ultrasonic-mechanical emulsification. The results showed that the emulsions from crude bio-oil and 0# diesel had the best stability, with a stability time of 31 days. The stability time of the bio-oil middle fraction emulsion was 216 min, while that of the bio-oil heavy fraction emulsion was as low as 14 min. The particle size distributions of the emulsions were analyzed by a Malvern particle size analyzer. Emulsion fuels made from crude bio-oil and the bio-oil middle fraction had a smaller droplet size of 8–60 nm. In contrast, the emulsion fuel from the alcohol-diluted bio-oil heavy fraction had much larger droplet size, reaching up to 6000 nm. Compared with single ultrasonic emulsification, ultrasonic-mechanical emulsification had positive effects on increasing the stability time of the crude bio-oil emulsion, but negative effects on the stability time of the bio-oil middle and heavy fraction emulsions. To explain the above differences, spherical shell mechanism models were proposed according to the composition properties of the crude bio-oil and its fractions.

Using Bio-oil Produced by Biomass Pyrolysis as Diesel Fuel

This study evaluated the effect of biomass (soybean oil, eucalyptus sawdust, and coffee grounds) pyrolysis oil on the formulation of diesel fuels. The parameters analyzed were ignition delay time, emission of particulate matter and unburned hydrocarbons, and specific fuel consumption. The fraction of pyrolysis oil used as fuel was obtained by vacuum distillation at 80–240 °C. The use of this fraction resulted in a decrease in the ignition delay time in the combustion process, with the resulting increase in the cetane number due to the presence of phenolic groups in the pyrolysis oil, which modify the formation mechanism of peroxyl radicals by altering the temperature of the flame front. Additionally, particulate matter emissions are reduced significantly by up to 30% when compared with the base fuel. This is probably due to the high solubility of water in pyrolysis oil, which leads to the formation of an azeotropic mixture that lowers the boiling point and contributes to vaporize the fuel inside the combustion chamber, reducing the formation of particulate matter. These results indicate the promising potential of this fraction for use in the formulation of diesel fuel, decreasing ignition delay and increasing the cetane number, as well as significantly reducing particulate matter emissions. The main difficulty in using this fraction of pyrolysis oil is its chemical stability, since it has a strong tendency to form oligomers.

Benefit assessment of cost, energy, and environment for biomass pyrolysis oil

This study used life cycle assessment (LCA) to clarify the feasibility and potential effects of a new type of bioenergy by evaluating the cost, energy, and environmental efficiency of biomass pyrolysis oil in the production and usage stages. An annual yield of 10,000 t of pyrolysis oil processed with the raw material of Cryptomeria residue was selected as the evaluated target. We used life cycle inventory and effect assessment to evaluate the advantages and disadvantages associated with the production of the new bioenergy. GaBi®4 software and the Eco-indicator 95 system were selected for the evaluation. The resulting calculated specific cost of pyrolysis oil production was NT$11,758/m3 pyrolysis oil (NT$1 = US$0.034 in October 2012), and pyrolysis oil with its byproduct could provide the energy of 36,019 MJ/m3 pyrolysis oil. The output–input energy ratio is approximately 13.2, indicating the high energy efficiency of pyrolysis oil. In terms of the environmental aspect, the total net carbon emission is 176.6 kg CO2/m3 pyrolysis oil. Using pyrolysis oil and the biochar byproduct to replace fuel oil and coal can produce a reduction of approximately 2835 kg CO2/m3 pyrolysis oil (0.079 kg CO2/MJ) of greenhouse gas emissions. The environmental impact indicator is 0.105 Pt, which is much lower than the fuel oil energy-equivalent. These findings suggest that pyrolysis oil produced from Cryptomeria residue yields enhanced energy and environmental efficiency. However, the production cost is higher than that of existing fossil fuels.

Lignin Pyrolysis Components and Upgrading—Technology Review

Biomass pyrolysis oil has been reported as a potential renewable biofuel precursor. Although several review articles focusing on lignocellulose pyrolysis can be found, the one that particularly focus on lignin pyrolysis is still not available in literature. Lignin is the second most abundant biomass component and the primary renewable aromatic resource in nature. The pyrolysis chemistry and mechanism of lignin are significantly different from pyrolysis of cellulose or entire biomass. Therefore, different from other review articles in the field, this review particularly focuses on the recent developments in lignin pyrolysis chemistry, mechanism, catalysts, and the upgrading of the bio-oil from lignin pyrolysis. Although bio-oil production from pyrolysis of biomass has been proven on commercial scale and is a very promising option for production of renewable chemicals and fuels, there are still several drawbacks that have not been solved. The components of biomass pyrolysis oils are very complicated and related to the properties of bio-oil. In this review article, the details about pyrolysis oil components particularly those from lignin pyrolysis processes will be discussed first. Due to the poor physical and chemical property, the lignin pyrolysis oil has to be upgraded before usage. The most common method of upgrading bio-oil is hydrotreating. Catalysts have been widely used in petroleum industry for pyrolysis bio-oil upgrading. In this review paper, the mechanism of the hydrodeoxygenation reaction between the model compounds and catalysts will be discussed and the effects of the reaction condition will be summarized.

Reaction Mechanism of Oxygenate Components of Biomass Pyrolysis Oil on HZSM-5 Zeolite

In this paper, phenol, m-cresol and cyclopentanone, chosen as model compounds, were catalyzed upgrading at 500 degrees C, space velocity 5.0 h(-1) and different water content conditions. The results showed that the phenol can't be catalyzed on the phase of zeolite HZSM-5. According to the catalytic pyrolysis products of m-cresol and cyclopentanone, simply catalytic reaction pathways were speculated that m-cresol cracking included demethylation and isomerizate reactions and cyclopentanone cracking was firstly dehydration or detarbonylation and then cyclized to produce cyclocompounds, which provided a theoretical basis for the bio-oil catalytic pyrolysis mechanism research.

Research Progress in the Bio-Oil Hydrotreating Process

Bio-oil derived from biomass fast pyrolysis and biodiesel are all clean and renewable energy, which have been paid more and more attention by relevant researchers. The technology of biomass pyrolysis oil’s refining and producing second generation biodiesel by hydrotreating process are developed rapidly. This article presents the new research progress in the bio-oil hydrotreating refining for fuel.

Production of renewable gasoline from aqueous phase hydrogenation of lignin pyrolysis oil

The hydrogenation of biomass pyrolysis oils to upgraded biofuels, especially the aliphatic compounds with a low boiling range has attracted significant research attention. However, compared with the water soluble phase of pyrolysis oils, the water insoluble parts are relatively difficult to upgrade due to the complex high molecular weight aromatic structures. To solve this problem, a two step hydrogenation of water insoluble pyrolysis oil (heavy oil) produced from pyrolysis of pine wood ethanol organosolv lignin (EOL) at 600°C for 30min was examined. Ru/C was used as the catalyst and water was used as the dispersant for the heavy oil and hydrogenation products. The carbon conversion yields for the first and second step hydrogenation are 35% and 33% (overall molar% of carbon content in the heavy oil), respectively. The products of first step of hydrogenation are primarily aromatic molecules which are produced from the hydrolytic cleavage of ether bond and methoxy groups in the heavy oils. Further hydrogenation was shown to covert the insoluble heavy oils (weight average molecular weight is 265g/mol) to the aliphatic alcohols and other aliphatic components which could be used as renewable gasoline. As far as we know, this is the first reported effort to upgrade water insoluble parts of lignin pyrolysis oil to the total aliphatic components by aqueous phase hydrogenation.

Fluid Catalytic Cracking of Biomass-Derived Oils and Their Blends with Petroleum Feedstocks: A Review

To reduce the carbon footprint and greenhouse gas (GHG) emissions associated with heavy crude oil/bitumen upgrading and refining in the production of clean transportation fuels, researchers are targeting the production of fuels from renewable energy resources. These resources are mainly biomass-derived oils, which include oils produced by biomass pyrolysis (bio-oil), edible and inedible vegetable oils, and animal fats. Over the past 2 decades, research has focused on the evaluation of biomass-derived oil processing using conventional fluid catalytic cracking (FCC), a technology responsible for producing the majority of gasoline in a petroleum refinery. The present review summarizes research associated with the FCC of various biomass-derived oil feedstocks as well as studies related to the co-processing of these oils with conventional petroleum feedstocks. The objective of this review is to present a comprehensive perspective of the effects of renewable oil processing on existing FCC technology, operation, catalysts, and product quality and quantity.

In Situ NMR Characterization of Pyrolysis Oil during Accelerated Aging

COMING OF AGE: A method for investigating the accelerated aging of biomass pyrolysis oils is reported. The in situ NMR investigation, done by using quantitative ¹H, ¹³C NMR and heteronuclear single-quantum correlation (HSQC)-NMR techniques, reveals the chemical structural changes of pyrolysis oil during the aging process, providing insight into the mechanism of aging process.

Co-processing of standard gas oil and biocrude oil to hydrocarbon fuels

The major obstacle in thermochemical biomass conversion to hydrocarbon fuels using pyrolysis has been the high oxygen content and the poor stability of the product oils, which cause them to solidify during secondary processing. We have developed a fractional catalytic pyrolysis process to convert biomass feedstocks into a product termed “biocrude oils” (stable biomass pyrolysis oils) which are distinct from unstable conventional pyrolysis oils. The biocrude oils are stable, low viscosity liquids that are storable at ambient conditions without any significant increases in viscosity; distillable at both atmospheric pressure and under vacuum without char or solid formation. About 15 wt% biocrude oils containing 20–25% oxygen were blended with 85 wt% standard gas oil and co-cracked in an Advanced Catalyst Evaluation (ACE™) unit using fluid catalytic cracking (FCC) catalysts to produce hydrocarbon fuels that contain negligible amount of oxygen. For the same conversion of 70% for both the standard gas oil and the biocrude oil/gas oil blends, the product gasoline yield was 44 wt%, light cycle oil (LCO) 17 wt%, heavy cycle oil (HCO) 13 wt%, and liquefied petroleum gas (LPG) 16 wt%. However, the coke yield for the standard gas oil was 7.06 wt% compared to 6.64–6.81 wt% for the blends. There appeared to be hydrogen transfer from the cracking of the standard gas oil to the biocrude oil which subsequently eliminated the oxygen in the fuel without external hydrogen addition. We have demonstrated for the first time that biomass pyrolysis oils can be successfully converted into hydrocarbons without hydrogenation pretreatment.

Preparation of Bio-Oil-Phenol-Formaldehyde Resins from Biomass Pyrolysis Oil

Three kinds of bio-oil-phenol-formaldehyde (BPF) resins were prepared which contained 30 wt% replacement of phenol with bio-oil derived from poplar, larch and bamboo. Main component of different pyrolysis bio-oil, physical properties of different BPF resins and their plywood specimens were investigated. The results show that phenolics in bio-oil derived from poplar, larch and bamboo are 13.8653%, 14.7529% and 10.3987%. All the experimental BPF resins have similar physical properties, which comply with GB/T 14732-2006. The performance of the plywood specimens bonded with different BPF resins were larch-BPF > poplar-BPF > bamboo-BPF, all of which could achieve the demands of GB/T 9846-2004.

The fate of bio-carbon in FCC co-processing products

A promising alternative to the first generation of bio-fuels is to produce mixed bio- and fossil fuels by co-processing mixtures of biomass pyrolysis oil with crude oil fractions obtained from distillation in a conventional oil refinery. This was demonstrated to be technically feasible for fluid catalytic cracking (FCC), which is the main refinery process for producing gasoline. However, co-processing leads to more coke formation and to a more aromatic gasoline fraction. A detailed understanding is necessary on how the oxygenated moieties effect the reaction mechanism to further improve the process/catalysts. Moreover, for technical and marketing reasons, it is absolutely required to accurately determine the proportion of renewable molecules in the commercialized products. The carbon-14 method (also called radiocarbon or 14C) has been used as the most accurate and powerful method to discriminate fossil carbon from bio-carbon, since fossil fuel is virtually 14C-free, while biofuel contains the present-day “natural” amount of 14C. This technique has shown that not all FCC products share bio-carbon statistically. The coke formed during a FCC cycle and to a lesser extent the gases are found richer in 14C than gasoline. This result gives valuable information on the co-processing mechanism, supporting that the bio-oil oxygenated molecules are processed more easily at the expenses of the crude oil hydrocarbons, favouring the bio-coke and the bio-light gases production.

Further Separation, Characterization, and Upgrading for Upper and Bottom Layers from Phase Separation of Biomass Pyrolysis Oils

Effective separation methods must be developed before bio-oils become a source of chemical products or liquid fuels by further upgrading. Phase separation is one effective pathway to realize an initial isolation of bio-oils. When aqueous salt solutions are added, phase separation of the pyrolysis bio-oil can occur to form two different phases: the upper layer with high contents of water, acetic acid, and water-soluble compounds and the bottom layers with low water content and high lignin pyrolysis compounds [Song, Q.-H.; Nie, J.-Q.; Ren, M.-G.; Guo, Q.-X.Effective phase separation of biomass pyrolysis oils by adding aqueous salt solutions. Energy Fuels 2009, 23 (6), 3307−3312]. In this paper, the salt-induced phase separation of bio-oils with 20 kinds of salt solutions was investigated. On the basis of the dependence of the mass ratio of the bio-oil bottom layer to the whole bio-oil sample upon the salt solution concentrations, it has been demonstrated that the phase separation derives from a normal ionic...

What Should We Demand from the Catalysts Responsible for Upgrading Biomass Pyrolysis Oil?

What Should We Demand from the Catalysts Responsible for Upgrading Biomass Pyrolysis Oil?

Real-Time Viscosity Measurements during the Accelerated Aging of Biomass Pyrolysis Oil

An oak bio-oil was aged at 90 °C using various times and methods. A novel method for aging bio-oils under shear is introduced and compared to standard (quiescent) aging experiments. In a hermetically sealed concentric cylinder rheometer, aging with shear for 8, 16, and 24 h showed increases in viscosity of 57, 300, and 720%, respectively. A similar increase in viscosity was observed after quiescently aging of sealed samples in a forced air oven (100, 120, and 740% after 8, 16, and 24 h, respectively). Another aging experiment under shear consisted of three 8 h aging steps with intermediate viscosity measurements. Viscosity increases were comparable to the 8, 16, and 24 h tests. A control experiment in the rheometer without shear found the increase in viscosity to be 30–50% less than the sheared experiments. The number-average molecular weight increased as samples were heat-treated at 90 °C for longer times. The water content showed small increases and decreases with aging, which was attributed to the hete...

Biomass pyrolysis oils for hydrogen production using chemical looping reforming

This study considers the feasibility of using highly oxygenated and volatile pyrolysis oils from biomass wastes as sustainable liquid fuels for conversion to a hydrogen-rich syngas using the chemical looping reforming process in a packed bed. Pine oil and palm empty fruit bunches oil- ‘EFB’- were investigated with a Ni/Al2O3 catalyst doubling as oxygen transfer material (OTM). The effect of molar steam to carbon ratio (S/C) and weight hourly space velocity were investigated at 600 °C and atmospheric pressure on the fuel and steam conversion, the H2 yield and the H- and C-products distribution. With a downward fuel feed configuration and using a H2-reduced catalyst, maximum averaged fuel conversions of ∼97% for pine oil and 89% for EFB oil were achieved at S/C ratios of 2.3 and 2.6 respectively (on a water-free oil basis). This produced H2 with a yield efficiency of approximately 60% for pine oil and 80% for EFB oil notwithstanding equilibrium limitations, and with little CH4 by-product. Both oils exhibited very similar outputs with varying S/C. Upon a short number of cycles, i.e. starting from an oil-reduced catalyst, the fuel conversion dropped slightly but the steam conversion was constant, resulting in a slow decrease in H2 yield. Despite their high level of oxygen content, the pyrolysis oils were shown to maintain close to 90% reduction of the oxidised catalyst upon repeated cycles, but the rate of reduction decreased with cycling.

Production and Analysis of Fast Pyrolysis Oils from Proteinaceous Biomass

Fast pyrolysis of lignocellulosic biomass is a facile method for producing high yields of liquid fuel intermediates. However, because most fast pyrolysis oils are highly oxygenated, acidic, and unstable, identification of feedstocks that produce higher quality pyrolysis liquids is desirable. Therefore, the effect of feedstock protein content was studied by performing fast pyrolysis experiments on biomass with varying protein content. The feedstocks ranged from low-protein content, ∼5% up to feedstocks with >40 wt.% protein content. Protein content was not a major factor in the yield of pyrolysis oil or the distribution of biomass carbon into the pyrolysis products. However, elevated levels of protein did cause a deoxygenation effect in the pyrolysis process with more of the oxygen rejected from the biomass as water. The deoxygenation caused the pyrolysis oil from the higher protein containing biomass to have higher energy content. Furthermore, the concentration of basic nitrogen groups caused the pyrolysis oil from the higher protein biomass to shift to a more neutral pH and lower total acid number than has been measured typically for lignocelluloic biomass pyrolysis oils. Some of the pyrolysis oils, particularly those from the mustard seed family presscakes exhibited better thermal stability than low-protein pyrolysis oils.

An Investigation of Wood-Plastic Novolac Modified by Biomass Pyrolysis Oils

The possibility of using water insoluble fraction from biomass pyrolysis oil as additive in synthesis of Wood-Plastic novolac has been proved by using Differential Scanning Calorimetry (DSC) and Fourier Transformed Infra Red (FT-IR) spectroscopy. Synthesis of novolac with different concentrations (10, 20 and 30 wt %) of water insoluble fraction were performed. It was found that mechanical properties were improved by using water insoluble fraction as additive. However, furthe increasing amount of water insoluble fraction, the mechanical properties of wood-plastic novolac were decreased. When the amount of water insoluble fraction in wood-plastic novolac was 10%, the flexural strength of wood-plastic novolac was 57.8 MPa, tensile strength was 29.5 MPa. The performance and thermal behavior of novolac were characterized by DSC and TG.

Catalytic upgrading of lignocellulosic biomass pyrolysis vapours: Effect of hydrothermal pre-treatment of biomass

The main objective of the present work was the study of the effect of hydrothermal pretreatment of lignocellulosic biomass (beech wood) on the product yields and bio-oil composition produced from biomass flash pyrolysis as well as from the catalytic upgrading of the biomass pyrolysis vapours. The hydrothermal pretreatment of lignocellulosic biomass was performed at a severity factor (Ro) of 3.55 leading to ∼35wt.% loss of solids, mainly due to solubilization and removal of hemicellulose. The production of sugars (mainly levoglucosan) was significantly increased by the use of the hydrothermally pretreated biomass instead of the untreated biomass in the non-catalytic flash pyrolysis experiments. On the other hand, the concentration of carboxylic acids, ketones and phenols was decreased in the bio-oil derived from the pretreated biomass. The catalysts tested in the upgrading of the biomass pyrolysis vapours were the strongly acidic zeolites H-ZSM-5 and silicalite (with very low number of acid sites) and the mildly acidic mesoporous aluminosilicate Al-MCM-41. The effect of catalysts on product yields and composition of bio-oil in the upgrading of pyrolysis vapours, was similar for both the pretreated and untreated biomass. The use of zeolite H-ZSM-5 decreased the total liquid yield (bio-oil) via decreasing the organic phase of bio-oil and increasing its water content, accompanied by increase of gases and moderate formation of coke on the catalyst. The zeolite silicalite and the Al-MCM-41 induced similar effects with those of H-ZSM-5 but to a less extent, except of the significantly higher coke that was deposited on Al-MCM-41. With regard to the composition of the bio-oil, all the catalysts and mostly the strongly acidic H-ZSM-5 zeolite reduced the oxygen content of the organic fraction, mainly by decreasing the concentration of acids, ketones and phenols in the untreated biomass pyrolysis oil or the concentration of sugars in the pretreated biomass pyrolysis oil. Aromatics and polycyclic aromatic hydrocarbons (PAHs) were significantly increased by the use of all catalysts, for both types of biomass feed. A substantial increase in the concentration of phenols was observed in the upgraded bio-oil derived by the hydrothermally pretreated biomass, using the less acidic silicalite and Al-MCM-41 catalysts.