Valorization of bio-oil from maple sawdust for transportation fuels

Fuels from biomass (biofuels) are used to mitigate the greenhouse gases produced through the utilization of fossil fuels. Non-edible or waste biomass can be pyrolized to produce bio-oil. The oil (an unstable and low energy product) can be further upgraded through hydrodeoxygenation to produce gas and/or diesel range hydrocarbons and value added chemicals. In this research, the valorization of fast pyrolysis bio-oil from maple sawdust was explored in two steps. Primarily, solvent extraction was carried out to remove water from the bio-oil (35% water, 55% oxygen and a heating value of 21.6 MJ/kg). The solvents explored were benzene, ethanol, and chloroform. Chloroform reduced the amount of high molecular oxygenates from 58 to 30%, increased the amount of hydrocarbons from 20 to 41%, and reduced the moisture content t

Hydrothermal Liquefaction of High-Water Content Biomass and Waste Materials for the Production of Biogas and Bio-Crude Oil

Growing interest in renewable energies due to shrinking reserves of fossil fuels and climate change concerns have led to extensive research towards gaseous and liquid fuels production from renewable energy resources such as biomass and wastes. Energy generation from municipal and industrial wastes such as wastewater sludge is also environmental friendly way to deal with large volume of waste disposal with the additional advantage of eliminating part of the indirect greenhouse gas emissions from energy crops-derived biofuels. In this thesis, a novel process for co-production of biogas and bio-crude oil from high-water-content wastewater sludge through hydrothermal liquefaction (HTL) treatments is developed. Hydrothermal liquefaction is a thermochemical process where raw sludge can be heat treated directly in the absence of oxygen and in the presence of water as the reaction medium mostly in subcritical or near critical conditions (T \u3c 374 oC and P \u3c 22.1 MPa). This eliminates the need to dewater/dry biomass which can be a major energy input for biofuel production via other processes such as pyrolysis or gasification. Since hydrothermal liquefaction is a promising technology for conversion of high-water-content biomass without the need of costly sludge dewatering, it could replace the conventional sludge treatment by making valuable energy products out of a waste material. Wastewater sludge was treated by two scenarios, operating at temperatures in a lower range (40-80 oC) and a higher range (200-350 oC), respectively. The low-temperature treatment was considered as sludge pre-treatment before anaerobic digestion, aiming to examine the possible relationship between increased solubilisation of the sludge as a result of the pre-treatment and its digestibility for biogas production. The high-temperature treatment scenario was performed to produce value-added products such as bio-crude oil from co-processing of wastewater sludge (more than 90% water content) with another type of lignocellulosic biomass to adjust substrate concentration to a higher level with better economics of the process, and to increase the bio-oil yield and quality. The main by-product from the high-temperature process (water-soluble product) was used as a potential feedstock for biogas production through anaerobic digestion

A review on biomass as a substitute energy source: Polygeneration influence and hydrogen rich gas formation via pyrolysis

Hydrogen rich gas production and advantages of polygeneration during biomass conversation through pyrolysis were extensively reviewed in this paper. Different innovative pyrolysis setups and the effect of reaction conditions such as pressure, temperature, catalyst type, biomass type, and reactor type on the formation of hydrogen and other value-added chemicals has been exploited. High temperatures and pressures together with application of catalysts was reported to favour the enhancement of hydrogen by promoting secondary pyrolysis reactions and hence the production of H2 gas. Compared to one-stage pyrolysis systems, pyrolysis data from two-stage pyrolysis reaction systems reported improved production of hydrogen and value-added chemicals due to the reforming of volatile matter in the second stage reactor. The polygeneration effect of biomass pyrolysis has also been reviewed, and it was observed that the polygeneration systems were significantly vital in covering the demand and supply of renewable energy

Cellulose Liquefaction : Optimization of Reaction Parameters

Tese de mestrado, Química Tecnológica, 2021, Universidade de Lisboa, Faculdade de CiênciasNeste trabalho estudou-se a optimização dos parâmetros reacionais da liquefação direta de biomassa lignocelulósica. O solvente usado foi 2-etilhexanol com um liquor ratio de 5:1 (solvente:biomassa), juntamente com o catalisador ácido p-toluenossulfónico (PTSA). Com o objectivo de obter a defnir um modelo experimental, foram efectuadas 17 reacções variando parâmetros como a temperatura, o tempo de reacção e a quantidade de catalisador. As condições ideais foram obtidas a 170 ºC, com 3 horas de reacção e 3% (m/m) de catalisador, resultando num rendimento de 84.8%. Os bio-óleos produzidos foram caracterizados por espectroscopia de infravermelhos e análise elementar tendo-se também determinado a densidade e as viscosidades cinemática e dinâmica. A avaliação dos resultados permitiu confirmar que a temperatura se trata do parâmetro reacional mais influente tendo-se concluído que abaixo dos 170 ºC não se verifica a formação de um grupo carbonilo no espectro FTIR do bio-óleo. O aumento de reacções secundárias com o aumento do tempo de reação também é verificado pela espectroscopia de infravermelhos. As propriedades químicas dos bio-óleos, como a densidade e ambos os tipos de viscosidade, aumentam com a conversão da celulose. A análise elementar permitiu estimar o HHV dos bio-óleos e dos resíduos sólidos tendo sido 30.16 MJ Kg-1 o maior valor obtido, um valor ainda distante dos derivados de combustíveis fósseis. No entanto, o HHV dos resíduos sólidos revelou-se superior ao da celulose pura potenciando a hipótese de aplicar o processo de liquefação ao resíduo sólido de liquefações posteriores.The present work studied the optimization of the reaction parameters in lignocellulosic biomass liquefaction. The solvent used was 2-ethylhexanol with a 5:1 liquor ratio (solvent:biomass) and the used catalyst was p-toluenosulfonic acid (PTSA). To understand the best reaction media for the biomass conversion, 17 reactions were performed varying the reaction temperature, reaction time and catalyst amount. The optimum conditions were 170 ºC, 3 hours and 3 wt%(m/m) of catalyst which produced the highest reported yield – 84.8%. The produced bio-oils were characterized by infrared spectroscopy and elementar analysis with the densities and viscosities, both kinematic and dynamic, also determined. The evaluation of the results confirmed that temperature is the most influential reactional parameter with the FTIR results showing that under 170 ºC no carbonyl groups are formed. The infrared spectroscopy also confirms the increase of secondary reactions with the longer reaction times. Density and viscosity values increased with the conversion of cellulose. The elementar analysis allowed to estimate the high heating value of the bio-oils and solid residues with the highest bio-oil HHV achieved being 30.16 MJ Kg-1 , a distant value from the ones derived from fossil fuels. Although, the solid-residues HHV were superior to pure cellulose’s HHV potentiating the hypothesis of reusing the solid residues for further liquefactions

Recent advances in thermochemical conversion of biomass into drop-in fuel:a review

This research article was published in the Journal of Scientific African Volume 17, September 2022The global evolutional changes towards the use of renewable energy sources for trans- portation purposes are on the increase in an attempt to mitigate the environmental haz- ard and the proposed depletion associated with fossil fuel resources. Pyrolysis and hy- drothermal processes of biomass conversion into renewable biofuels are resulted into the production of biocrude with high oxygen content due to the presence of large amount of oxygenates in biomass feedstocks. The presence of oxygen content in bio-oil causes cor- rosion, low heating value, instability and high viscosity in bio-oil. These challenges have necessitated the application of upgrading techniques such as catalytic hydrodeoxygenation process among others. The presence of several oxygenated compounds made the mech- anisms of bio-oil synthesis difficult and model bio-oil were reviewed to understand the effects of process parameters and catalysts on aromatic selectivity and conversion. The se- lectivity of aromatic hydrocarbons was affected by deactivation of catalysts’ active sites. Coke formation has been identified as one of the common and notorious causes of cata- lysts’ deactivation which is dependent on the nature of feedstock, conditions of operation and the nature of catalyst. Therefore, the need to develop, evaluate a structurally and ther- mally stable catalyst with high catalyst recovery and reusability are of importance in the quest to depict hydrodeoxygenation process as an excellent technique for bio-oil upgrad- ing

Progress in biofuel production from gasification

Biofuels from biomass gasification are reviewed here, and demonstrated to be an attractive option. Recent progress in gasification techniques and key generation pathways for biofuels production, process design and integration and socio-environmental impacts of biofuel generation are discussed, with the goal of investigating gasification-to-biofuels’ credentials as a sustainable and eco-friendly technology. The synthesis of important biofuels such as bio-methanol, bio-ethanol and higher alcohols, bio-dimethyl ether, Fischer Tropsch fuels, bio-methane, bio-hydrogen and algae-based fuels is reviewed, together with recent technologies, catalysts and reactors. Significant thermodynamic studies for each biofuel are also examined. Syngas cleaning is demonstrated to be a critical issue for biofuel production, and innovative pathways such as those employed by Choren Industrietechnik, Germany, and BioMCN, the Netherlands, are shown to allow efficient methanol generation. The conversion of syngas to FT transportation fuels such as gasoline and diesel over Co or Fe catalysts is reviewed and demonstrated to be a promising option for the future of biofuels. Bio-methane has emerged as a lucrative alternative for conventional transportation fuel with all the advantages of natural gas including a dense distribution, trade and supply network. Routes to produce H2 are discussed, though critical issues such as storage, expensive production routes with low efficiencies remain. Algae-based fuels are in the research and development stage, but are shown to have immense potential to become commercially important because of their capability to fix large amounts of CO2, to rapidly grow in many environments and versatile end uses. However, suitable process configurations resulting in optimal plant designs are crucial, so detailed process integration is a powerful tool to optimize current and develop new processes. LCA and ethical issues are also discussed in brief. It is clear that the use of food crops, as opposed to food wastes represents an area fraught with challenges, which must be resolved on a case by case basis

Recent Insights into Lignocellulosic Biomass Pyrolysis: A Critical Review on Pretreatment, Characterization, and Products Upgrading

Pyrolysis process has been considered to be an efficient approach for valorization of lignocellulosic biomass into bio-oil and value-added chemicals. Bio-oil refers to biomass pyrolysis liquid, which contains alkanes, aromatic compounds, phenol derivatives, and small amounts of ketone, ester, ether, amine, and alcohol. Lignocellulosic biomass is a renewable and sustainable energy resource for carbon that is readily available in the environment. This review article provides an outline of the pyrolysis process including pretreatment of biomass, pyrolysis mechanism, and process products upgrading. The pretreatment processes for biomass are reviewed including physical and chemical processes. In addition, the gaps in research and recommendations for improving the pretreatment processes are highlighted. Furthermore, the effect of feedstock characterization, operating parameters, and types of biomass on the performance of the pyrolysis process are explained. Recent progress in the identification of the mechanism of the pyrolysis process is addressed with some recommendations for future work. In addition, the article critically provides insight into process upgrading via several approaches specifically using catalytic upgrading. In spite of the current catalytic achievements of catalytic pyrolysis for providing high-quality bio-oil, the production yield has simultaneously dropped. This article explains the current drawbacks of catalytic approaches while suggesting alternative methodologies that could possibly improve the deoxygenation of bio-oil while maintaining high production yield