Upgrading of Oils from Biomass and Waste: Catalytic Hydrodeoxygenation (original) (raw)
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Catalytic Upgrading of Pyrolytic Oil via In-situ Hydrodeoxygenation
Waste and Biomass Valorization, 2019
Lignocellulosic biomass derived from non-food crops cultivated on lands that are increasingly marginal for more favoured major crops is a potential source of sustainable renewable energy. This study explores the transformation of crude organic phase pyrolytic oil derived from Napier grass biomass into high-grade biofuel precursors via hydrodeoxygenation reaction over platinum and palladium catalysts with in-situ hydrogen generation from methanol. The reaction was conducted in a high-pressure stainless steel batch reactor at 350 °C, 20 wt% methanol ratio, 2 wt% catalyst loading and 60 min reaction time. The result of physicochemical analysis showed that the higher heating value of the organic liquid products collected over the catalysts increased by 35-40% relative to the raw sample. Gas chromatography-mass spectrometry results revealed significant reductions in the oxygenated compounds such as methoxyaromatics, methoxyphenols, acids, aldehydes. The degree of deoxygenation and overall extent of upgrading observed was 50-54% and 56-60%, respectively. The gas products collected were mainly carbon monoxide, carbon dioxide, hydrogen and methane. Hydrodeoxygenation, hydrogenolysis, hydrogenation, dehydration, demethylation, hydrocracking, decarbonylation and decarboxylation were the main upgrading reactions, and a multiple reaction network was proposed.
Fuel Processing Technology, 2014
In this paper, we sought to elucidate the relationships between biomass feedstock type and the suitability of their fast-pyrolysis bio-oils for hydrodeoxygenation (HDO) upgrading. Switchgrass, Eucalyptus benthamii, and equine manure feedstocks were pyrolyzed into bio-oil using a continuous fast-pyrolysis system. We also synthesized variations of switchgrass bio-oil using catalytic pyrolysis methods (HZSM-5 catalyst or tail-gas recycle method). Bio-oil samples underwent batch HDO reactions at 320°C under~2100 psi H 2 atmosphere for 4 h, using Pt, Ru, or Pd on carbon supports. Hydrogen consumption was measured and correlated with compositional trends. The resulting organic, aqueous, and gas phases were analyzed for their chemical compositions. Mass balances indicate little coke formation. Switchgrass bio-oil over Pt/C performed the best in terms of hydrogen consumption efficiency, deoxygenation efficiency, and types of upgraded bio-oil compounds. Eucalyptus feedstocks consistently consumed more than twice the normal amount of hydrogen gas per run, primarily due to the elevated syringol content. Catalytically pyrolyzed bio-oils deoxygenated poorly over Pt/C but hydrogenated more extensively than other oils. Although the relative deoxygenation (%DO rel ) varied based on feedstock and catalyst, the absolute deoxygenation (%DO abs ) depended only on the overall yield. The total extent of upgrading (hydrogenation + deoxygenation) remained independent of feedstock and catalyst.
Upgrading of Bio Oil into High Value Hydrocarbons via Hydrodeoxygenation
American Journal of …, 2010
Problem statement: World energy consumption is forecasted to grow significantly for the foreseeable future with fossil fuel remains the governing energy source. The demand in the need to explore alternative fuel source was further triggered by the overwhelmingly inconsistent cost of gasoline. Bio-oil is an alternative energy source produced from pyrolysis of biomass. However it is undesirable as a ready alternative transportation fuel due to its unfavorable nature i.e., highly oxygenated and low octane number. To overcome these physicochemical issues, hydrodeoxygenation reaction is a possible upgrading method i.e., by partial or total elimination of oxygen and hydrogenation of chemical structures. Hence, this study aimed to investigate feasible routes and to develop the process route to upgrade the pyrolytic bio-oil from biomass into value-added chemicals for the production of transportation fuel, i.e., benzene and cyclohexane, via hydrodeoxygenation process via simulation in PETRONAS iCON software. Approach: In this study, hydrodeoxygenation of phenols and substituted phenols was used to represent the hydrodeoxygenation of the major oxygen compound in bio-oil due to their low reactivity in HDO. Results: By assuming the feedstock used was 1% of the total palm shell available in Malaysia, i.e., 2,587 kg h −1 bio-oil, the simulation predicted the production of 226 kg h −1 benzene, 236 kg h −1 cyclohexane and 7 kg h −1 cyclohexene, with the yield of 34, 81 and 3% respectively. The preliminary economic potential was calculated to be positive. It was also observed that hydrogen was the limiting reactant in the hydrogenation reaction. Conclusion/Recommendations: The simulation study indicated positive technical and economic feasibility of hydrodeoxygenation of pyrolytic bio-oil from biomass into benzene and cyclohexane for the transportation fuel industry. This potential can be explored in more details and further findings can promote the prospect of co-processing bio-oil in standard refinery units to produce chemicals and fuels.
Upgrading of pinyon-juniper catalytic pyrolysis oil via hydrodeoxygenation
Energy, 2017
In this study we discuss hydrodeoxygenation (HDO) of pinyon juniper (PJ) catalytic pyrolysis oil over Ni/SiO 2-Al 2 O 3 catalyst in a batch reactor to improve the physicochemical properties of the oil. The influence of temperature (350-500 °C), reaction time (15-90 min), and initial hydrogen pressure (3.5-10 MPa), on hydrodeoxygenation of PJ pyrolysis oil was investigated. After hydrogenation was completed, gas, coke, and a liquid product of two immiscible phases (aqueous and organic), were obtained. Maximum HDO of bio-oil was achieved at 450 ° C while the initial hydrogen pressure was 7 MPa and the reaction time was 30 minutes. Under these conditions, the H/C and O/C atomic ratios changed from 1.29 and 0.29 respectively for bio-oil to 2.36 and 0 for HDO oil respectively. The higher heating value increased from 27.64 MJ/kg of bio-oil to 45.58 MJ/kg of upgraded oil. The water content of organic liquid product was less than 0.05 wt% while it was 1.63 wt% in the feed. The viscosity of upgraded oil was 1.26 cP compared to119 cP for the crude bio-oil.
A review of catalytic upgrading of bio-oil to engine fuels
As the oil reserves are depleting the need of an alternative fuel source is becoming increasingly apparent. One prospective method for producing fuels in the future is conversion of biomass into bio-oil and then upgrading the bio-oil over a catalyst, this method is the focus of this review article. Bio-oil production can be facilitated through flash pyrolysis, which has been identified as one of the most feasible routes. The bio-oil has a high oxygen content and therefore low stability over time and a low heating value. Upgrading is desirable to remove the oxygen and in this way make it resemble crude oil. Two general routes for bio-oil upgrading have been considered: hydrodeoxygenation (HDO) and zeolite cracking. HDO is a high pressure operation where hydrogen is used to exclude oxygen from the bio-oil, giving a high grade oil product equivalent to crude oil. Catalysts for the reaction are traditional hydrodesulphurization (HDS) catalysts, such as Co–MoS 2 /Al 2 O 3 , or metal catalysts, as for example Pd/C. However, catalyst lifetimes of much more than 200 h have not been achieved with any current catalyst due to carbon deposition. Zeolite cracking is an alternative path, where zeolites, e.g. HZSM-5, are used as catalysts for the deoxygenation reaction. In these systems hydrogen is not a requirement, so operation is performed at atmospheric pressure. However, extensive carbon deposition results in very short catalyst lifetimes. Furthermore a general restriction in the hydrogen content of the bio-oil results in a low H/C ratio of the oil product as no additional hydrogen is supplied. Overall, oil from zeolite cracking is of a low grade, with heating values approximately 25% lower than that of crude oil. Of the two mentioned routes, HDO appears to have the best potential, as zeolite cracking cannot produce fuels of acceptable grade for the current infrastructure. HDO is evaluated as being a path to fuels in a grade and at a price equivalent to present fossil fuels, but several tasks still have to be addressed within this process. Catalyst development, understanding of the carbon forming mechanisms, understanding of the kinetics, elucidation of sulphur as a source of deactivation, evaluation of the requirement for high pressure, and sustainable sources for hydrogen are all areas which have to be elucidated before commercialisation of the process.
Recent Catalytic Advances in Hydrotreatment Processes of Pyrolysis Bio-Oil
Catalysts
Catalytic hydrotreatment (HT) is one of the most important refining steps in the actual petroleum-based refineries for the production of fuels and chemicals, and it will play also a crucial role for the development of biomass-based refineries. In fact, the utilization of HT processes for the upgrading of biomass and/or lignocellulosic residues aimed to the production of synthetic fuels and chemical intermediates represents a reliable strategy to reduce both carbon dioxide emissions and fossil fuels dependence. At this regard, the catalytic hydrotreatment of oils obtained from either thermochemical (e.g., pyrolysis) or physical (e.g., vegetable seeds pressing) processes allows to convert biomass-derived oils into a biofuel with properties very similar to conventional ones (so-called drop-in biofuels). Similarly, catalytic hydro-processing also may have a key role in the valorization of other biorefinery streams, such as lignocellulose, for the production of high-added value chemicals...
Renewable fuels via catalytic hydrodeoxygenation
Applied Catalysis A: General, 2011
There is considerable interest in investigating the deoxygenation process, due to the high oxygen content of the feed-stocks used for the production of renewable fuels. This review addresses studies related to the catalytic hydrodeoxygenation of two feed-stocks (a) oils with high content of triglycerides and (b) oils derived from high pressure liquefaction or pyrolysis of biomass. Future research directions that could potentially bridge the existing gaps in these areas are provided.
Application, Deactivation, and Regeneration of Heterogeneous Catalysts in Bio-Oil Upgrading
Catalysts, 2016
The massive consumption of fossil fuels and associated environmental issues are leading to an increased interest in alternative resources such as biofuels. The renewable biofuels can be upgraded from bio-oils that are derived from biomass pyrolysis. Catalytic cracking and hydrodeoxygenation (HDO) are two of the most promising bio-oil upgrading processes for biofuel production. Heterogeneous catalysts are essential for upgrading bio-oil into hydrocarbon biofuel. Although advances have been achieved, the deactivation and regeneration of catalysts still remains a challenge. This review focuses on the current progress and challenges of heterogeneous catalyst application, deactivation, and regeneration. The technologies of catalysts deactivation, reduction, and regeneration for improving catalyst activity and stability are discussed. Some suggestions for future research including catalyst mechanism, catalyst development, process integration, and biomass modification for the production of hydrocarbon biofuels are provided.
Catalytic upgrading of bio-oil via the hydrodeoxygenation of short chain carboxylic acids
2019
Petroleum is non-renewable and contributes to environmental pollution, thus bio-oil can be substituted as a potential alternative. However, bio-oil in its crude form cannot be used directly as fuel since it contains a high proportion of oxygenated, acidic and reactive compounds such as carboxylic acids. These are known to cause corrosion of vessels and pipework, instability and phase separation. The oxygen content of bio-oil can be reduced through hydrodeoxygenation of oxygenated compounds. In this study, the hydrogenation of short chain (C2-C4) carboxylic acids typical of model compounds present in bio-oil was investigated using commercial Pt supported on Al2O3, SiO2, carbon and graphite, and prepared Pt and Pt-Re on TiO2 catalysts. This study reports the preparation of 4% Pt/TiO2 and 4% Pt-4%Re/TiO2 catalysts for alcohol production, which were screened against their commercial counterparts, the reaction space explored in the following ranges temperature 80-200 °C, pressure 10-40 b...
Title: Atmospheric hydrodeoxygenation of bio-oil oxygenated model compounds: A review
Hydrodeoxygenation (HDO) of various bio oil oxygenated model compounds in low H2 pressure has been discussed in this study. Because of the high yield of aromatic mixtures in bio-oil, they carry great potential for fuel efficiency. Nevertheless, due to its high viscosity, abundance of acid, and heteroatom contaminants, the bio-oil ought to be upgraded and hydrotreated in order to be applied as an alternative fuel. A continuous low H2 pressure HDO of bio-oil is favored as it could be simply integrated with conventional pyrolysis systems, functioning at low pressures, as well as supporting a flexible plan for serial processing in respective bio-refineries. Additionally, such a process is cheaper and safer in comparison with the high pressure set ups. This review meticulously elaborates on the operation conditions, challenges, and opportunities for using this process in an industrial scale. The operating temperature, the H2 flow ratio, the active site, and the catalyst stability are some important factors to be considered when it is intended to reach a high conversion efficiency for the HDO in low H2 pressure.