Catalytic Upgrading Of Bio-oil Research Articles

Selective production of high-value fuel via catalytic upgrading of bio-oil over nitrogen-doped carbon-alumina hybrid supported cobalt catalysts

Bio-oil derived from biomass fast pyrolysis can be upgraded to gasoline and diesel alternatives by catalytic hydrodeoxygenation (HDO). Here, the novel nitrogen-doped carbon–alumina hybrid supported cobalt (Co/NCAn, n = 1, 2.5, 5) catalyst is established by a coagulation bath technique. The optimized Co/NCA2.5 catalyst presented 100 % conversion of guaiacol, high selectivity to cyclohexane (93.6 %), and extremely high deoxygenation degree (97.3 %), respectively. Therein, the formation of cyclohexanol was facilitated by stronger binding energy and greater charge transfer between Co and NC which was unraveled by density functional theory calculations. In addition, the appropriate amount of Lewis acid sites enhanced the cleavage of the C–O bond in cyclohexanol, finally resulting in a remarkable selectivity for cyclohexane. Finally, the Co/NCA2.5 catalyst also exhibited excellent selectivity (93.1 %) for high heating value hydrocarbon fuel in crude bio-oil HDO. This work provides a theoretical basis on N dopants collaborating alumina hybrid catalysts for efficient HDO reaction.

Catalytic bio-oil upgrading using Fe-Co/Al2O3 and co-processing with vacuum gas oil

The current study explores the hydrodeoxygenation (HDO) of pine sawdust derived pyrolysis bio-oil and co-processing of raw bio-oil with Vacuum Gas Oil (VGO) in a micro-activity testing (MAT) unit. The catalytic performance of mono- and bi-metallic catalysts were tested for bio-oil upgrading. Notably, FeCo (2:1)/Al2O3 catalysts exhibited superior HDO activity compared to their mono-metallic counterparts. Co-processing of raw bio-oil (2–10 wt%) with VGO led to a notable increase in gasoline yield of ∼48% with a 6 wt% blend. Maximum conversion was achieved with 8 wt% blend, further increasing the proportion, conversion decreased significantly affecting the product distribution.

Catalytic upgrading of bio-oil from halophyte seeds into transportation fuels

Because of socioeconomic considerations, wide-scale production of biofuel necessitates the utilization of nonedible biomass feedstock that does not compete for land and fresh water resources. In this regard, Salicornia bigelovii (SB) is the most investigated halophyte species. The high oil content in SB seeds has sparked mounting research that aims to utilize SB as an industrial crop in the production of bio-oil, particularly in coastal areas where these plants thrive. However, the oil extracted from the pyrolysis of raw SB seeds is largely dominated by oxygenated fatty acids, most notably 9,12-octadecadienoic acid and 9,17-octadecadienal, typical to that of other crops. The pyrolysate bio-oil of the raw SB seeds exhibited a relative yield of oxygenated compounds that decreased from 57.05 % at 200 °C to 9.81 % at 500 °C, and the relative yield of nitrogenated compounds increased from 4.86 % at 200 °C to 21.97 % at 500 °C. To improve the quality of the produced bio-oil, herein we investigated the catalytic hydrodeoxygenation (HDO) of the fragments that were produced from the thermal degradation of SB seeds. A 5 %Ni–CeO2 catalyst was prepared and characterized by a wide array of methods X-ray diffraction, X-ray photoelectron spectroscopy, temperature programmed reduction, scanning electron microscope, Brunauer-Emmett-Teller analysis, and thermogravimetric analyzer. The catalytic run was executed between 200 and 500 °C in a flow reactor. The deployed catalytic methodology displayed a profound HDO capacity. At 400 °C, for instance, the gas chromatography mass spectroscopy (GC–MS) detected loads of paraffin and aromatic compounds exists at appreciable values of 48.0 % and 28.5 %, respectively. With a total relative yield of 43.2 % (at 400 °C), C8–C15 species (i.e., jet fuel fractions) were the most abundant species in the upgraded SB bio-oil. The release of H2, CO, CO2, and CH4 was analyzed qualitatively and quantitatively using gas chromatography thermal conductivity detector and Fourier infrared spectroscopic analysis. When the Ni–CeO2 catalyst was utilized, a complete deoxygenated bio-oil was obtained from SB seeds using the surface-assisted HDO reaction. On the basis of the elemental analysis, the biochar's hydrogen and oxygen contents were found to decrease significantly. Density functional theory computations showed mechanisms for reactions that underpinned the experimentally observed hydrodeoxygenation process. Outcomes presented herein shall be instrumental toward the effective utilization of halophyte in the production of commercial transportation fuels.

Facile demineralization of biochar and its catalytic upgrading of bio-oil from fast pyrolysis of bagasse

Catalytic conversion of volatiles from biomass pyrolysis over biochar and its mechanism are important to the efficient utilization. The properties of biochar including alkali/alkaline earth metallic species (AAEMs) and pore structure exert the influence on bio-oil quality. In this work, a facile demineralization method by CO2-enhanced water leaching (CEWL) of biochar from bagasse pyrolysis was first applied to catalytic upgrading of pyrolysis bio-oil. The effect of AAEMs content and pore structures in biochar catalysts on upgrading performances was investigated. The results show that the CEWL of biochar can effectively remove most inherent AAEMs without obviously destroying pore structures. Pore structure of catalysts plays a dominant role in increasing phenols contents to 47.7% over CO2-activated biochar from 25.8% without biochar. The reaction mechanism was proposed that AAEMs enhanced the polymerization of aromatic hydrocarbons and the decarbonylation of the oxygenated compounds. High temperature is profitable to the generation of phenols and polycyclic aromatic hydrocarbons owing to easier decarbonylation of ketones and demethylation or demethoxylation of phenols.

Catalytic Upgrading of Bio-oil from Ulva lactuca using Amberlyst-15 Catalyst: Experimental and Kinetic Model

Catalytic Upgrading of Bio-oil from Ulva lactuca using Amberlyst-15 Catalyst: Experimental and Kinetic Model

Synergistic Effect of Acid Sites and a Gallium-Based Modified Meso-/Microporous Catalyst for the Pyrolysis of Biomass

Single-metal and bimetal catalysts were synthesized by the modification of a meso-/microporous composite catalyst (ZSM-5@SBA-15) with the oxides of gallium, zinc, and nickel by ion exchange (iex) and impregnation (imp), followed by their application in the catalytic upgrading of bio-oil via the pyrolysis of biomass.The results revealed that the yields of high value-added products of hydrocarbons (e.g., toluene and naphthalene) significantly catalytic pyrolysis over bimetal catalysts improved comparison with that over a non-metal modified catalyst, that is, product yield increased from 2.9 area% to 10.6 area%. Moreover, the possible mechanism for catalytic pyrolysis over the best-performing catalyst of Ga/Zn-ZSM-5@SBA-15-iex (gallium, zinc-modified meso-/microporous ZSM-5@SBA-15 by ion-exchange method) with the highest aromatic selectivity and effective reduction of carbonyl compounds (e.g., carboxides) was proposed by assuming the systematic comparison of structural features and catalytic performances of various metal/ZSM-5@SBA-15-type catalysts and fundamental investigation of the synergetic effects dominated by acidic sites, type of metal and bimetal catalysts.

Conversion of soybean soapstock into hydrocarbon fuel by microwave-assisted catalytic fast pyrolysis using MCM-41/HZSM-5 in a downdraft reactor

Microwave-assisted catalytic pyrolysis of biomass is a promising technology to obtain hydrocarbon rich fuel oil. In consideration of this method, HZSM-5 is currently recognized as a catalyst with a good effect. However, given the small pore diameter and easy coking of HZSM-5, the catalytic upgrading of bio-oil is limited to a certain extent. In this study, MCM-41 and HZSM-5 were used for joint catalysis to explore the effect of catalytic temperature, the ratio of two catalysts, and the ratio of soybean soapstock and catalysts on the pyrolysis products. The optimal reaction conditions included the following: catalytic temperature, 400 °C; MCM-41/HZSM-5 ratio, 1:1; feedstock/catalyst ratio, 2:1. The results showed that MCM-41 could effectively alleviate the coking of HZSM-5, and the use of both catalysts reduced the bio-oil yield but effectively improved the selectivity of monocyclic aromatic hydrocarbons in bio-oil, thus increasing the value of bio-oil.

Catalytic upgrading of bio-oil from bagasse: Thermogravimetric analysis and fixed bed pyrolysis

The objective of this work was to upgrade bio-oil from bagasse by pyrolysis using catalyst/biomass of three different compositions (5, 15 and 20 wt% HZSM-5 loadings). The thermal analysis and product distribution experiments were carried out in a thermogravimetric analyzer (TGA) and a fixed bed reactor, respectively. In TGA, the pyrolysis of catalytic runs shifted the thermograph curves to the lower temperatures and generated high yield residues compared to that obtained from non-catalytic run. From a fixed-bed condition, the maximum bio-oil yield from non-catalytic and catalytic runs at a temperature of 500 °C at 15% ZSM-5 catalyst concentration were 49.4% and 21.1 wt% respectively. Aromatics, phenols and oleic acids are the main chemical components deduced from gas chromatography/mass spectrometry (GC–MS) analysis of the bio-oil. Bio-oil from catalytic pyrolysis had more aromatics (desirable component) and less oleic acid (undesirable component) than the bio-oil from non-catalytic pyrolysis. The study of bio-oil from catalytic bagasse pyrolysis enhances desirable component when used as transportation fuel. Besides addition of catalyst improving the degradation mechanism of biomass also alters the product composition closer to the aromatic range hydrocarbon.

Effects of supercritical fluids in catalytic upgrading of biomass pyrolysis oil

The catalytic upgrading of biomass pyrolysis oil (bio-oil) was performed under supercritical conditions. The behaviors of solvents with MgNiMo/AC were investigated for use of methanol, ethanol, butanol, hexanol, and formic acid as supercritical fluids. The production of gases including hydrogen, carbon monoxide, carbon dioxide, and methane was analyzed, and changes in the compositions of esters, alcohols, and phenols were examined. When the catalyst dosage and temperature were increased, the production of hydrogen increased. Among the alcohols, methanol produced the highest amount of hydrogen, and butanol produced the lowest amount of hydrogen. Formic acid showed good hydrogen-production ability. After catalytic upgrading of bio-oil, there was a decrease in oxygen and moisture content and an increase in the higher heating value (HHV). With an extended reaction time, the oxygen content was lowered further. During the supercritical ethanol reaction at 340 °C under an initial 30 bar of N2 gas for 2 h the oxygen content decreased from 33.9 to 14.6 wt% and the HHV increased from 25.2 to 35.3 MJ/kg.

Catalytic upgrading of bio-oil in hydrothermal liquefaction of algae major model components over liquid acids

We selected acetic acid and sulfuric acid as liquid acid catalysts to investigate their performance on hydrothermal liquefaction (HTL) of algae major model components, including polysaccharides, proteins, lipids, and polysaccharides-proteins mixture. The aim of this study was to understand the catalytic effects of liquid acid catalysts as well as the formation process mechanisms and properties of the bio-oils from HTL of algae. We also used the two acids in HTL process of Chlorella vulgaris to estimate their catalytic performances in algae and compare this performance with the results from HTL of model components. Product distributions from different catalytic conditions were compared with blank results. Bio-oils were analyzed by elemental analysis, gas chromatography-mass spectrometry (GC–MS), and thermal gravimetric analysis (TGA). The results showed that the addition of acetic acid or sulfuric acid had no positive effect on the enhancement of bio-oil yield from HTL of individual algae major model components; however, the use of liquid acid catalysts could prevent the detrimental effect of interaction between polysaccharides and proteins on bio-oil yield. H/C ratios and higher heating values (HHVs) of bio-oils obtained from HTL of algae major model components increased significantly in the presence of acid catalysts. Sulfuric acid favored the oxygen removal process, and acetic acid reduced the nitrogen content in bio-oil from HTL of proteins. GC–MS results showed that bio-oil composition was greatly altered when adding acids. The light component proportion of catalytic upgraded bio-oils was significantly higher than that of bio-oils obtained with no catalyst. The results of HTL of Chlorella vulgaris with acid catalysts indicate that both acids favor to the hydrolysis of cellulose; therefore, the use of acid catalysts could accelerate the formation of bio-oil from cellular components. The difference between the HTL of algae major model components and real algae using acid catalysts was probably due to the complexity of algae structure.

Toward Fast Pyrolysis-Based Biorefinery: Selective Production of Platform Chemicals from Biomass by Organosolv Fractionation Coupled with Fast Pyrolysis

The heterogeneous structure of biomass causes the complex compositions of bio-oil, thereby posing huge challenges for the extraction of value-added chemicals from bio-oil and the catalytic upgrading of bio-oil in existing petroleum-refining infrastructures. In order to overcome these challenges, a new advanced biorefinery based on organosolv fractionation coupled with fast pyrolysis is first proposed. The experimental results showed that biomass can be effectively divided into cellulose-rich fractions, organosolv lignins, and xylose by organosolv fractionation, thus improving the relative yields of platform chemicals (levoglucosan (LG) and phenols) in subsequent fast pyrolysis. The relative LG yields from eucalyptus, pine, and bagasse increased from 4.8, 3.5, and 2.1 wt % to 42.1, 22.7, and 59.8 wt %, respectively. These findings provide a simple and efficient integrated process to selective production of platform chemicals, which is different from the existing processes, e.g. catalytic fast pyrolysis and...

Catalytic upgrading of bio-oil by simultaneous esterification and alkylation with azeotropic water removal

Due to the negative effects of acids and aldehydes, crude bio-oil has to be upgraded before its application as a high-graded fuel. A novel method for bio-oil upgrading by simultaneous catalytic esterification and alkylation with azeotropic water removal using n-butanol and 2-methylfuran was investigated in this work. Under the optimum upgrading conditions, water content was evidently decreased from 27.82% to 3.21%, and acid number was reduced from 41.12mg NaOH/g to 6.17mg NaOH/g. High heating value of upgraded bio-oil was more than 2 times higher than crude bio-oil and the other properties were also improved significantly. GC-MS analysis indicated that labile acids, aldehydes, ketones and lower alcohols were transformed to stable target products. The introduction of 2-methylfuran effectively suppressed acetalization reactions and the yields of more stable alkylation products were higher than acetals. In addition, oxygenated liquid fuel and sugars and their derivatives could be effectively separated from upgraded bio-oil by H2O/CH2Cl2 extraction. The main product in crude sugars part was butyl-β-D-glucopyranoside, which was formed by means of hydrolysis of levoglucosan and the following glycosidation.

Stepwise Enrichment of Sugars from the Heavy Fraction of Bio-oil

Sugars are among the main compounds in bio-oil produced by biomass pyrolysis. However, they can easily form coke, resulting in fast deactivation of the catalyst and severe blockage of the reactor during catalytic upgrading of bio-oil. Molecular distillation may be performed to retain sugars and pyrolytic lignin in the heavy fraction and thus to provide a primary stage for the subsequent sugar separation and utilization. A new method involving extraction, heat treatment, and column chromatography was introduced to separate further the aqueous phase obtained from the bio-oil heavy fraction by methanol–water extraction. Thus, monophenols and sugars were coextracted through these combined separation technologies. A fraction rich in monophenols was obtained by solvent extraction. Other impurities were further removed by heat treatment and column chromatography. An alcohol sedimentation method further separated the combined sugar-rich fraction into an ethanol-soluble fraction (SF-1) and an ethanol-insoluble fra...

Immediate catalytic upgrading of soybean shell bio-oil

The pyrolysis of soybean shell and the immediate catalytic upgrading of the bio-oil over an equilibrium FCC catalyst was studied in order to define its potential as a source for fuels and chemicals. The experiments of pyrolysis and immediate catalytic upgrading were performed at 550 °C during 7 min with different catalysts to oil relationships in an integrated fixed bed pyrolysis-conversion reactor. The results were compared under the same conditions against those from pine sawdust, which is a biomass source commonly used for the production of bio-oil. In the pyrolysis the pine sawdust produced more liquids (61.4%wt.) than the soybean shell (54.7%wt.). When the catalyst was presented, the yield of hydrocarbons increased, particularly in the case of soybean shell, which was four time higher than in the pyrolysis. The bio-oil from soybean shell produced less coke (between 3.1 and 4.3%wt.) in its immediate catalytic upgrading than that from pine sawdust (between 5 and 5.8%wt.), due to its lower content of phenolic and other high molecular weight compounds (three and five times less, respectively). Moreover, soybean shell showed a higher selectivity to hydrocarbons in the gasoline range, with more olefins and less aromatic than pine sawdust.

Catalytic Hydrogenation of Bio-oil Over RhCl(PPh3)3/MCM-41(NH2) and RuCl2(PPh3)3/MCM-41(NH2)

Homogeneous RuCl2(PPh3)3 and RhCl(PPh3)3 complexes were heterogenized on amine functionalized MCM-41. The heterogeneous ruthenium and rhodium complexes were used for catalytic upgrading of bio-oil under mild conditions (50–90°C). Both showed good activity in the hydrogenation of aldehydes and phenols with C=C side chains in bio-oil. The stability and properties of the bio-oil improved significantly. By comparison, the heterogenized rhodium catalyst was more effective than the ruthenium catalyst. Moreover, the catalysts still showed good activity after three reaction cycles. The results demonstrated that the utilization of heterogenized homogenous metal complexes was a promising treatment for upgrading bio-oil.

Biofuel production from catalytic microwave pyrolysis of Douglas fir pellets over ferrum-modified activated carbon catalyst

The presented study aims to improve the quality of bio-oils by catalytic upgrading of bio-oil from microwave pyrolysis of Douglas fir pellet using transition metal modified activated carbon (AC) catalyst. A central composite experimental design (CCD) was used to optimize the reaction conditions for high quality bio-oil production. The effects of reaction temperature and reaction time on product yields were investigated. GC/MS analysis indicated that the main chemical compounds (including furans, phenols, guaiacols, and ketones/ethers) of bio-oils were in the range of 80–87% of bio-oils for most of the samples. The ketones/ethers were mainly composed of 2-cyclopen-1-one; straight chain ethers were increased up to about 38% of bio-oil; and the phenols increased from 2.5% to about 10% of the bio-oils after upgrading accompanying with the decrease of guaiacols in comparison with raw biomass pyrolysis. The reaction mechanism of this process was analyzed.

Catalytic Upgrading of Bio-oil over Ni-Based Catalysts Supported on Mixed Oxides

Ni-Based catalysts using mixed oxides of Al2O3–SiO2, Al2O3–TiO2, TiO2–SiO2, and TiO2–ZrO2 as supports were evaluated for hydrotreatments using guaiacol as the model compound and characterized by N2...

Catalytic Upgrading of Bio-Oil by Reacting with Olefins and Alcohols over Solid Acids: Reaction Paths via Model Compound Studies

Catalytic refining of bio-oil by reacting with olefin/alcohol over solid acids can convert bio-oil to oxygen-containing fuels. Reactivities of groups of compounds typically present in bio-oil with 1-octene (or 1-butanol) were studied at 120 °C/3 h over Dowex50WX2, Amberlyst15, Amberlyst36, silica sulfuric acid (SSA) and Cs2.5H0.5PW12O40 supported on K10 clay (Cs2.5/K10, 30 wt. %). These compounds include phenol, water, acetic acid, acetaldehyde, hydroxyacetone, d-glucose and 2-hydroxymethylfuran. Mechanisms for the overall conversions were proposed. Other olefins (1,7-octadiene, cyclohexene, and 2,4,4-trimethylpentene) and alcohols (iso-butanol) with different activities were also investigated. All the olefins and alcohols used were effective but produced varying product selectivities. A complex model bio-oil, synthesized by mixing all the above-stated model compounds, was refined under similar conditions to test the catalyst’s activity. SSA shows the highest hydrothermal stability. Cs2.5/K10 lost most of its activity. A global reaction pathway is outlined. Simultaneous and competing esterification, etherfication, acetal formation, hydration, isomerization and other equilibria were involved. Synergistic interactions among reactants and products were determined. Acid-catalyzed olefin hydration removed water and drove the esterification and acetal formation equilibria toward ester and acetal products.

Effects of Feeding Rate on Catalytic Pyrolysis of Sawdust in Bubbling Fluidized Beds

Catalytic cracking of sawdust has been studied numerically in bubbling fluidized beds with in situ catalyst. The upgrading of bio-oil is one of the critical issues in applications of biomass pyrolysis products. Due to the interactions of multiphase flow dynamics coupled with chemical reaction, computational modelling of thermo-chemical processing of biomass can be quite complex. In current work, the online catalytic upgrading of bio-oil derived by sawdust pyrolysis is investigated. The Eulerian-Eulerian models coupled with the Kinetic Theory of Granular Flows are employed to model the multiphase flow in fluidized beds. The user defined functions (UDF) is developed based on the chemical kinetics to represent the decomposition of biomass and upgrading of bio-oil. The simulation results show that the heterogeneous reactions can perform significant effects on hydrodynamics of fluidized beds while different space time, the ratio of catalyst mass to tar flow rate, will vary the yield distribution of products.

Ni-based sol–gel catalysts as promising systems for crude bio-oil upgrading: Guaiacol hydrodeoxygenation study

Catalytic hydrotreatment or hydrodeoxygenation (HDO) has been researched extensively with the crude bio-oil and its model compounds over conventional sulfided Ni(Mo), Co(Mo) catalysts and supported noble metal catalysts. These types of catalysts showed themselves unsuitable for the target HDO process, which resulted in an urgent need to search for a new catalytic system meeting such requirements as low cost, stability against coke formation and leaching of active components due to adverse effect of the acidic medium (bio-oil). In the present work a series of Ni-based catalysts with different stabilizing components has been tested in the hydrodeoxygenation (HDO) of guaiacol (2-methoxyphenol), bio-oil model compound. The process has been carried out in an autoclave at 320°C and 17MPa H2. The main products were cyclohexane, 1-methylcyclohexane-1,2-diol, and cyclohexanone. The reaction scheme of guaiacol conversion explaining the formation of main products has been suggested. The catalyst activity was found to rise with an increase in the active component loading and depend on the catalyst preparation method. The most active catalysts in HDO of guaiacol were Ni-based catalysts prepared by a sol–gel method and stabilized with SiO2 and ZrO2. According to TPR, XRD, XPS, and HRTEM, the high activity of these catalysts correlates with the high nickel loading and the high specific area of active component provided by the formation of nickel oxide–silicate species. The effect of temperature on the product distribution and catalyst activity in the target process (HDO) has been investigated as well. The catalysts were shown to be very promising systems for the production of hydrocarbon fuels by the catalytic upgrading of bio-oil.