Composition Of Bio-oil Research Articles

Pyrolysis behavior of cellulose in a fixed bed reactor: Residue evolution and effects of parameters on products distribution and bio-oil composition

Significant discrepancies of cellulose pyrolysis behavior in a micro-scale pyrolyzer and that in a large-scale reactor hinder the industrial application of those findings obtained from the former reactor. In this work, the pyrolysis behavior of cellulose in a fixed bed reactor was investigated, especially the residue evolution and the effects of temperature, material thickness and carrier gas flow rate on the products distribution and bio-oil composition. And a possible pathway for the cyclopentanones formation was proposed and competing reactions during cellulose pyrolysis with the consideration of heat and mass transfer effect were analyzed. It was found that high temperature promoted the cellulose decomposition and favored the cellulose to produce furfural, cyclopentanones and light linear compounds (such as acetic acid, hydroxy actaldehyde), and relative low temperature (<450 °C) and thicker material thickness (>2 mm) favored the dehydration of cellulose to yield levoglucosenone and furans compounds, and fast carrier gas flow rate declined the yield of most compounds but favored the recovery of levoglucosan. The findings of present study, to some extent, could provide guidance on process optimization of cellulose pyrolysis in a large-scale reactor to produce desired chemicals.

Recent advances in the catalytic pyrolysis of microalgae

Abstract The catalytic pyrolysis of microalgae offers a strategic means of increasing the value of pyrogenic products. Microalgae are a promising pyrolysis feedstock. This review summarizes the state-of-the-art catalytic pyrolysis processes to form bio-oil with a high proportion of aromatic compounds. The focus is on the current knowledge of the mechanisms to form aromatic hydrocarbon species from the catalytic pyrolysis of microalgae. In addition, that the effects of the reaction conditions and catalyst selection on the yield and composition of microalgal bio-oil are reviewed. The information shows that the catalyst and feedstock properties are closely associated with the formation of desired aromatic compounds. In addition, this review defines the technical challenges that need to be overcome and suggests future research for the further development of catalytic pyrolysis technologies for the production of aromatics from microalgae.

Volatiles reaction during pyrolysis of corn stalk – Its influence on bio-oil composition and coking behavior of volatiles

Reaction of nascent volatiles is unavoidable during biomass pyrolysis and significantly influences the product yield, bio-oil quality and coking on the reactor wall. However, experimental studies in this aspect are still very limited. This work aims to advance the knowledge in this aspect using a two-stage reactor. Volatiles were generated in-situ from pyrolysis of corn stalk at 540 °C and swept off to the second-stage reactor preheated at 440–650 °C with a residence time of 1.5–4.7 s. The bio-oil quality was evaluated using simulated distillation gaschromatography. Results show that with increasing the volatiles temperature, the bio-oil yield decreases but the quality is improved: the contents of phenols, aldehydes and monocyclic aromatics increase significantly, those of esters and alcohols increase slightly and the contents of ketones, acids and furans decreases. Effect of volatiles residence time on the bio-oil quality depends on the volatiles temperature: becoming worse at 440 °C and better at 600 °C with increasing the residence time. The volatiles reaction also generates a few tetrahydrofuran-insoluble compounds, depositing on the downstream wall of the second-stage reactor (termed coke-wall) or suspending in bio-oil (termed soot-oil). The coke-wall yield increases with increasing volatiles temperature and residence time and is generally higher than the soot-oil yield.

Microwave-assisted catalytic fast pyrolysis coupled with microwave-absorbent of soapstock for bio-oil in a downdraft reactor

Microwave-assisted pyrolysis of biomass with HZSM-5 coupled with SiC as microwave-absorbent in a downdraft reactor is a promising method for obtaining hydrocarbon-rich bio-oil. The hydrocarbon content limits the economic and commercial viability of the bio-oil produced by pyrolysis. In this study, the effects of catalytic temperature, feedstock-to-catalyst ratio, and WHSV on the yield and composition of bio-oil are studied. In addition, this study compared the influence of downdraft reaction and updraft reaction on the yield and composition of bio-oil. Furthermore, the stability of the catalyst is studied. Catalytic temperature and feedstock-to-catalyst ratio played pivotal roles in the yield and composition of bio-oil. WHSV has minimal influence on the bio-oil yield and composition within the scope of our research. Furthermore, the optimal catalytic temperature, feedstock-to-catalyst ratio and WHSV were 400 °C, 2:1, and 72 h−1, respectively. The results illustrated that the downdraft coupled with the microwave-absorbent was conducive to the formation of aromatic hydrocarbons. The HZSM-5 performed well in five replicate experimental cycles under optimal conditions in terms of bio-oil yield and aromatic hydrocarbon yield.

High-Resolution Mass Spectrometry Study of the Bio-Oil Samples Produced by Thermal Liquefaction of Microalgae in Different Solvents.

We have performed a comparative analysis of the bio-oil produced by thermal liquefaction of microalgae in different solvents using high-resolution Orbitrap mass spectrometry and GC-MS approach. Water, methanol, ethanol, butanol, isopropanol, acetonitrile, toluene, and hexane were used as solvents in which the liquefaction was performed. It was observed that all resulting oils demonstrate a considerable degree of similarity. For all samples, compounds containing 1 and 2 nitrogen atoms dominated in the positive ESI spectra, while a relative contribution of other compounds was small. In negative ESI mode, compounds having 2 to 7 oxygens were observed. Statistical analysis revealed that products can be combined in two groups depending on the solvent used for the liquefaction. To the first group, we can attribute the products obtained by using protic (alcohols) and to the second by using aprotic (acetonitrile, toluene) solvents. Nevertheless, based on our results, we concluded that solvent possesses a minor impact on molecular composition of bio-oil. We suggested that the driving force of the liquefaction reaction is the thermal dehydration of the carbohydrate in algae, resulting in water formation, which could be the trigger of the producing of bio-oil. To prove this hypothesis, we performed the reaction with the dry algae in the absence of the solvent and observed the formation of bio-oil. Graphical Abstract.

Synergistic bio-oil production from hydrothermal co-liquefaction of Spirulina platensis and α-Cellulose

Hydrothermal liquefaction (HTL) is a promising technology for the conversion of wet biomass into liquid fuels. In this study, the hydrothermal co-liquefaction (HTCL) of Spirulina platensis and α-Cellulose for bio-oil production was investigated. The bio-oil yield of HTCL was increased significantly by blending α-Cellulose with low-lipid content microalgae of Spirulina platensis in the absence of any catalysts supplementary which reduces the processing cost. The results showed that bio-oil productivity was increased drastically up to 40.33 wt % (28.53 wt % with pure Spirulina platensis and 14.47 wt % with pure α-Cellulose), with a positive synergistic effect (SE) of 16 wt % during the HTCL process. The composition of synthesized bio-oil was analyzed by GC-MS which revealed that HTCL of Spirulina platensis and α-Cellulose are to decrease of its heterocyclic compounds, increased esters and hydrocarbons contents than HTL of pure Spirulina platensis or α-Cellulose. The possible reaction pathways were derived by synthesized bio-oil composition. The maximum energy recovery rate 82% was obtained on HTCL process. The study concluded that, HTCL process is more favorable for the economic concern due to high convention of bio-oil efficiency.

Process optimization of biomass liquefaction in isopropanol/water with Raney nickel and sodium hydroxide as combined catalysts

Liquefaction co-catalyzed by Raney nickel and NaOH in isopropanol (2-PrOH)/H2O is an efficient method for transforming lignocellulosic biomass into bio-oil. The present study investigated the effect of reaction temperature, residence time, and dosage of the catalysts on the yield and composition of bio-oil. To understand the liquefaction mechanism, the transformation of lignin and cellulose at the same conditions was investigated as well. The results indicated that 240 °C was the optimum temperature in terms of bio-oil yield. It was also found that residence time had a great effect on not only the bio-oil yield but also the composition and higher heating value (HHV) of the bio-oil. Increasing the dosage of the catalysts also improved the yield and HHV of bio-oil. Most phenols in bio-oil were originated from lignin, while most ketones and hydrocarbons were produced by cellulose.

Pyrolysis of cellulose mixed with ionic liquids 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [bmim][TFSI], 1-butyl-3-methylimidazolium tetrafluoroborate [bmim][BF4], and 1-butyl-2,3-dimethylimidazolium tetrafluoroborate [bmmim][BF4

In this research, cellulose was impregnated with ionic liquid as a pretreatment and then also used as a catalyst in the subsequent pyrolysis of the cellulose to produce a bio-oil. Impregnating cellulose with ionic liquid is expected to decrease the necessary pyrolysis temperature and improve the liquid bio-oil chemical composition. [bmim][TFSI], [bmim][BF4], and [bmmim][BF4] treated cellulose samples increased liquid yields at 225 °C to ∼15% compared to untreated cellulose with a liquid yield of 4% representing a ∼400% increase in liquid yield. However, as the pyrolysis temperature is increased, the advantage of using ionic liquid to increase liquid yield diminishes. FTIR analysis of the char shows that the pyranose ring structure breaks apart at a lower temperature for the ionic liquid pretreated cellulose. GC-MS analysis shows that the ionic liquids have different effects on the liquid composition and improve the composition of the bio-oil by decreasing acids and ketones. Based on these results, reaction pathways are discussed for the different ionic liquids. In this paper, a better understanding of how ionic liquid affects cellulose pyrolysis was achieved and explains how ionic liquids increased bio-oil yields at low temperatures.

Investigating the effect of Cu/zeolite on deoxygenation of bio-oil from pyrolysis of pine wood

Pyrolysis is one of the significant technologies that can utilize lignocellulose biomass to produce different bioenergy fuels, such as bio-oil, pyrolytic gases and bio-char. The application of pyrolysis has been extensively studied to produce bio-oil, which is foreseen as the potential transportation fuel in the near future. However, the presence of oxygenated compounds, such as phenols and alcohols in bio-oil makes it highly acidic and unstable for a suitable transportation fuel. These oxygenated compounds can be converted to refinable hydrocarbons by using different catalysts. Therefore, this study aimed to prepare a catalyst that is Cu10%-zeolite and investigated its deoxygenation activity for bio-oil produced from pyrolysis of pine wood sawdust. The catalyst was prepared by a wet-impregnation method. Subsequently, the catalyst was characterized by X-ray diffraction and transmission electron microscopy. Furthermore, the catalyst was applied for in-situ (catalyst: biomass=5) and ex-situ catalytic pyrolysis (catalyst: biomass=3) and the results were compared with those from sole zeolite support. The pyrolysis process was carried out at a heating rate of 100 °C/min to a final temperature of 700 °C and the composition of bio-oil was examined by gas chromatography-mass spectroscopy. The results revealed that Cu-zeolite showed significant deoxygenation activity for bio-oil as compared to zeolite or without any catalyst. Evidently, Cu-zeolite after in-situ pyrolysis produced bio-oil with 20.9% aromatic hydrocarbons and 7.5% aliphatic hydrocarbons, which were approximately 80% and several times higher than with only zeolite, respectively. Meanwhile the concentration of alcohols was reduced from 47.5% to 5%. On the other hand, bio-oil produced from ex-situ catalytic pyrolysis was enriched with 41.6% aromatic hydrocarbons while only 1% alcohols were present in bio-oil. This promising deoxygenation activity can be ascribed to Cu-zeolite’s catalytic activity that converted phenol and alcohols to refinable hydrocarbons via various reactions, such as dehydration, decarboxylation and decarbonylation.

Conversion of Wood Waste to be a Source of Alternative Liquid Fuel Using Low Temperature Pyrolysis Method

Conversion of wood waste into bio-oil with low temperature pyrolysis method has been successfully carried out using tubular transport reactors. Pyrolysis carried out at temperatures of 250-300°C without using N2 gas. Bio-oil purified by a fractionation distillation method to remove water and light fraction compounds. The materials obtained from different types of wood waste, namely: Randu wood (Ceiba pentandra), Sengon wood (Paraserianthes falcataria), Coconut wood (Cocos nucifera), Bangkirei wood (Shorea laevis Ridl), Kruing wood (Dipterocarpus) and Meranti wood (Shorea leprosula). Bio-oil products are analyzed for their properties and characteristics, namely the nature of density, acidity, high heat value (HHV), and elements contained in bio-oil such as carbon, nitrogen and sulfur content based on SNI procedures, while bio-oil chemical compositions are investigated using Gas Chromatography Mass Spectroscopy (GC-MS). The maximum yield of bio-oil products occurs at 300°C by 40%. Bio-oil purification by fractional distillation method can produce purity of 16-31% wt. The characterization results of the chemical content of bio-oil showed that bio-oil of methyl formate, 2,6-dimetoxy phenol, 1,2,3 trimethoxy benzene, levoglucosan, 2,4-hexadienedioic acid and 1,2- benzenediol.

Role of neutral extractives and inherent active minerals in pyrolysis of agricultural crop residues and bio-oil formations

The work reports a comparative study on the pyrolysis of five agricultural crop residues (peanut straw, cotton straw, sorghum stalk, corn stalk and reed) using a gas-sweeping fixed bed reactor. The study aims at clarifying the role played by the neutral extractives and inherent active minerals in the pyrolysis characteristics, product distributions and bio-oil compositions. Among five crop residues, reed showed the highest bio-oil yield but with the highest oxygen content and the lowest HHV (higher heat value), in relation to the least alkali and alkaline earth metals (AAEMs) in it. Peanut straw had a content of neutral extractives as high as 47.4%, which contributed to the formations of a significantly higher proportion of long chain aliphatic hydrocarbons and liquid nitrogenous compounds, distinct from four other crop residues. Peanut straw was also highly enriched with AAEMs, which was responsible for a strong catalytic activity for the selective deoxygenation of bio-oil. Neutral extractives in sorghum stalk and corn stalk formed some long chain fatty oxygenates and less nitrogenous compounds. The bio-oils derived from these two biomasses contained oxygenates as dominant compounds, however, they had a lower fraction of heavy constituents, lower oxygen contents, and higher HHVs than those of reed and cotton straw. This result was attributed to the catalyzed bio-oil deoxygenation by the relatively abundant AAEMs in sorghum stalk and corn stalk.

Dioxane-based extraction process for production of high quality lignin

In the present study, lignin was extracted from debarked bamboo waste of paper industry by soxhlet extraction method with 1,4–Dioxane as main solvent (along with small quantities of catalyst and water). 10 g of biomass results in 1.5 g of lignin through soxhlet process. The purity of extracted lignin was determined, followed by structural and thermal properties using FTIR and TGA. The elemental composition and mass of lignin was determined by elemental analyser and gel permeation chromatography (GPC). The extracted lignin was found to be highly pure, with very low (0.42% w/w) ash and negligible carbohydrate content. The solubility of extracted lignin in various organic solvents like dioxane, THF, DMF, etc. makes it advantageous over lignin derived from other processes. Pyrolytic oil and char were also obtained through pyrolysis of extracted lignin. The composition of bio-oil and biochar was analysed. The results showed that pyrolytic oil was rich in aromatic content and biochar was high in carbon content.

Bio-oil upgrading with catalytic pyrolysis of biomass using Copper/zeolite-Nickel/zeolite and Copper-Nickel/zeolite catalysts

The bio-oil obtained from a general pyrolysis process contains a higher concentration of oxygenated compounds and the resultant physical and chemical properties make it an unsuitable drop-in fuel. The oxygenated compounds in the bio-oil can be converted into hydrocarbons or less oxygenated compounds with the application of catalysts. This study demonstrated the bio-oil upgrading with the application of catalysts, comparing the catalytic effect of combined mono-metallic catalysts (Cu/zeolite and Ni/zeolite) and sole bi-metallic catalyst (CuNi/zeolite) on the composition of bio-oil and pyrolytic gases. The results demonstrated that in comparison to the combined mono-metallic catalysts, the sole bi-metallic catalyst showed better deoxygenation for all the oxygenated compounds and favoured the production of aliphatic hydrocarbons, whereas the combination of mono-metallic catalysts generated higher proportion of aromatic hydrocarbons in the bio-oil. In both cases, the catalysts equally favoured decarboxylation and decarbonylation reactions, as CO2/CO of approximately 1 was obtained during the pyrolysis process.

Enhancement of light aromatics from catalytic fast pyrolysis of cellulose over bifunctional hierarchical HZSM-5 modified by hydrogen fluoride and nickel/hydrogen fluoride

Pore structure and accessible active sites of HZSM-5 (Z5) are the key factors for its catalysis. The bifunctional hierarchical Z5 were prepared with leaching agent HF and loading Ni, and their performance for catalytic fast pyrolysis (CFP) of cellulose was investigated in a drop tube quartz reactor. Z5 modified with 0.5 mol/L HF (0.5F-Z5) showed excellent light aromatics (LAs) yield, which can be attributed to the enhancement in the small mesopores (2–10 nm) and the decrease of Brønsted acid sites during dealumination. Simultaneously, the loading of a 1 wt% Ni produced more LAs than 0.5F-Z5, due to the improvement in deoxidation/hydrogenation reactions. The highest LAs yield (31.3%) was obtained over 1%Ni-0.5 mol/LHF-Z5, which increased by 44.9% compared to the parent Z5. In addition, the reaction routes over different active centers and acid-catalyzed reactions were analyzed, based upon the composition of bio-oils and catalyst characterization.

Microwave-assisted pyrolysis of vegetable oil soapstock: Comparative study of rapeseed, sunflower, corn, soybean, rice, and peanut oil soapstock

In this study, the effects of catalytic temperature and the type of soapstock on products from microwave-assisted pyrolysis were investigated. HZSM-5 was used as the catalyst to study the pyrolysis of six different soapstocks at 200°C, 300°C, and 400°C catalytic temperature. Results showed that the bio-oil yields initially increased and then decreased with the increase in catalytic temperature. When the catalytic temperature was 300°C, the bio-oil reached up to the maximum value (65.8 wt.%). Findings indicated that the composition of bio-oil was related to the degree of unsaturation of fatty acids sodium in the soapstocks. In the case of saturated fatty acid sodium, a series of alkanes was formed, whereas the pyrolysis of monounsaturated fatty acid sodium resulted mainly in cycloalkanes, the cycloalkenes obtained from bio-oil was produced by polyunsaturated fatty acid sodium. Keywords: microwave pyrolysis vegetable oil soapstock, HZSM-5, bio-oil DOI: 10.25165/j.ijabe.20191206.4599 Citation: Wang Y P, Zhang S M, Wu Q H, Duan D L, Liu Y H, Ruan R, et al. Microwave-assisted pyrolysis of vegetable oil soapstock: Comparative study of rapeseed, sunflower, corn, soybean, rice, and peanut oil soapstock. Int J Agric & Biol Eng, 2019; 12(6): 202–208.

Unravelling the catalytic influence of naturally occurring salts on biomass pyrolysis chemistry using glucose as a model compound: a combined experimental and DFT study

Alkali and alkaline-earth metal loaded biomass pyrolysis highlights that different metal ions have different effects on bio-oil composition.

Analytical Py-GC/MS of Genetically Modified Poplar for the Increased Production of Bio-aromatics

Genetic engineering is a powerful tool to steer bio-oil composition towards the production of speciality chemicals such as guaiacols, syringols, phenols, and vanillin through well-defined biomass feedstocks. Our previous work demonstrated the effects of lignin biosynthesis gene modification on the pyrolysis vapour compositions obtained from wood derived from greenhouse-grown poplars. In this study, field-grown poplars downregulated in the genes encoding CINNAMYL ALCOHOL DEHYDROGENASE (CAD), CAFFEIC ACID O-METHYLTRANSFERASE (COMT) and CAFFEOYL-CoA O-METHYLTRANSFERASE (CCoAOMT), and their corresponding wild type were pyrolysed in a Py-GC/MS. This work aims at capturing the effects of downregulation of the three enzymes on bio-oil composition using principal component analysis (PCA). 3,5-methoxytoluene, vanillin, coniferyl alcohol, 4-vinyl guaiacol, syringol, syringaldehyde, and guaiacol are the determining factors in the PCA analysis that are the substantially affected by COMT, CAD and CCoAOMT enzyme downregulation. COMT and CAD downregulated transgenic lines proved to be statistically different from the wild type because of a substantial difference in S and G lignin units. The sCAD line lead to a significant drop (nearly 51%) in S-lignin derived compounds, while CCoAOMT downregulation affected the least (7–11%). Further, removal of extractives via pretreatment enhanced the statistical differences among the CAD transgenic lines and its wild type. On the other hand, COMT downregulation caused 2-fold reduction in S-derived compounds compared to G-derived compounds. This study manifests the applicability of PCA analysis in tracking the biological changes in biomass (poplar in this case) and their effects on pyrolysis-oil compositions.

Hydrothermal processing of pine wood: effect of process variables on bio-oil quality and yield

Hydrothermal liquefaction processes (HTL) comprise complex chemical and physical transformations of biomass under the conditions of high temperature and pressure, commonly near- or supercritical water. During this processes, the components of biomass undergo various complicated chemical reactions strongly influenced by process variables. In this study, lignocellulosic biomass (pine wood) has been converted via liquefaction in subcritical water to bio-oil, water-soluble organics, gas and solid products. The process parameters (i.e. temperature and time processing) affecting the bio-oil yields and composition were comparatively studied. The chemical composition of resulting bio-oils was analyzed by means of mid-infrared spectroscopy, gel permeation chromatography, gas chromatography coupled to mass spectrometry and elemental analysis. The maximum bio-oil yield (38.35 wt.%) was obtained at 350 ºC for 10 min. The HHV of the obtained resultant bio-oils varied in the range of 24-28 MJ kg-1. Bio-oils from HTL of pine wood are complex mixtures of aromatic and cyclic compounds with numerous hydroxyl and carboxyl functional groups. The experiments exhibited that the increase in the temperature results in adeeper decomposition of biomass manifested by the higher yield of bio-oil and its gradual deoxygenation. In fact, the obtained oil products are promising, valuable intermediates, which may act as a source of many valueadded chemicals.

Biorefinery process for production of bioactive compounds and bio-oil from Camellia oleifera shell

A biorefinery process was developed in this study to obtain bioactive compounds and bio-oil from Camellia oleifera shells. Four different extraction techniques (water, ethanol, ultrasound-assisted deionized water, and ultrasound-assisted ethanol) were utilized to extract tea saponin and tannin from C. oleifera shells. Results showed that ethanol had better extraction capacity than did deionized water, and ultrasound could promote the dissolution of tannin and tea saponin in solution. The thermogravimetric curves of the samples treated under the four conditions moved toward high temperatures. This phenomenon indicated the thermal stability of the residue was significantly improved. The pretreatment showed a slight effect on the chemical compositions of bio-oil. Specifically, the samples treated with ethanol and ultrasound-assisted deionized water contained higher phenol contents (81.07% and 81.52%, respectively) than the other samples. The content of organic acid decreased with an increase in the phenol content. Keywords: Camellia oleifera shell, bio-oil, bioactive compounds, biorefinery, ultrasound-assisted extraction, pyrolysis DOI: 10.25165/j.ijabe.20191205.4593 Citation: Wang Y P, Ke L Y, Yang Q, Peng Y J, Hu Y Z, Dai L L, et al. Biorefinery process for production of bioactive compounds and bio-oil from Camellia oleifera shell. Int J Agric & Biol Eng, 2019; 12(5): 190–194.

A systematic review of the relationship between childhood maltreatment and risk of adolescent drug use

Sub/supercritical water liquefication (SCWL) is a water-based thermochemical technology as well as an environmentally friendly treatment by converting wet feedstock into bioenergy. In the present study, a systematic investigation of SCWL of lignite was carried out covering a temperature range between 320 and 440 °C when residence time increased from 5 min to 40 min. The highest bio-oil oil yield of 34.3% with solid residue of 52.7% was obtained at 440 °C for 5 min. Phenol derivatives, carboxylic acids, long chain hydrocarbons, ketones, and naphthalene were the main bio-oil composition through FTIR and GC-MS analysis. Gas yields and their exact compositions were also determined and CO2 was the dominate gas product but the percentage of CH4 became significant at severe SCWL conditions. A conclusion was drawn that fast liquefaction (e.g. 5 min) at relative higher temperature (e.g. 400 °C) which avoid excessive gasification and repolymerization reactions was an optimization strategy for high yield bio-oil production from SCWL of lignite.