Compounds In Bio-oil Research Articles

Preparation of Fe promoted MoS2 catalysts for the hydrodeoxygenation of p-cresol as a model compound of lignin-derived bio-oil

Fe promoted MoS2 catalysts were prepared by one-step hydrothermal method and then applied into the hydrodeoxygenation (HDO) of p-cresol as a model compound of lignin-derived bio-oil. The as-prepared samples had FeS2 and MoS2 phases with low crystallinity. After further hydrogen-treatment at 250 °C in dodecane, some peaks to FeS phase were observed. The surface area of Fe promoted MoS2 catalyst decreased firstly and then increased with Fe content in the catalysts increasing. In the HDO of p-cresol, the addition of Fe sulfides into MoS2 enhanced conversion and toluene selectivity. When the Fe/Mo molar ratio is 0.7:1, the conversion and deoxygenation degree reached up to 96.3% and 95.7% after reaction at 250 °C for 3 h, respectively. The high HDO activity was attributed to the synergistic effect and contact surface area between Fe sulfides and MoS2. During the HDO recycling reaction, the deactivation was observed, which resulted from the sulfur loss and the formation of Fe oxides, but its activity could be regenerated after a simple sulfuration procedure.

Microwave pyrolysis of Laminaria digitata to produce unique seaweed-derived bio-oils

Microwave pyrolysis has become an attractive form of processing technology to generate bio-oil, bio-char and syngas from different biomass feedstocks. In this study, microwave pyrolysis was performed on the UK native seaweed Laminaria digitata and its extract residue from a bio-refinery process. Pyrolysis of these two feedstocks was successfully achieved without the requirement of microwave susceptors, as pelletizing the biomass was sufficient to allow microwave pyrolysis to occur. It was found that average energy requirements as low as 1.84–2.83 kJ g−1 were required to pyrolyse 55–70% of both feedstocks and bio-oil yields of 5–8% and 10–14% for native and extraction residue L. digitata were produced, respectively. Maximum microwave pyrolysis processing times were in the order of 200 s. The bio-oil generated from both feedstocks contained no phenolic based compounds, but a greater number of nitrogen-containing compounds and compounds derived from macroalgal polysaccharides. Yields of certain compounds differed in bio-oils generated from the two L. digitata feedstocks, however it was observed that specific energy did not have a direct influence on bio-oil compound yield. Furthermore, the identification of a particular nitrogen-containing compound L-Proline, 1-methyl-5-oxo-, methylester is thought to be a unique product of microwave pyrolysis when carbon-based additives are avoided.

Upgrading Bio-Oil Produced from Corn Cobs and Cedrela odorata via Catalytic Olefination and Esterification with 3,7-Dimethyloct-1-ene and Butanol

In this study, corn cobs (CC) and Cedrela odorata (CO) sawdust which are common waste materials in Nigeria were used as raw materials in the production of bio-oil through pyrolysis at 500°C, for 2 h. The biochar produced in the process was sulfonated with concentrated sulfuric acid under reflux at 150°C for 6 h and used as a solid acid catalyst for bio-oil upgrading. The bio-oil was upgraded by simultaneous olefination and esterification using 3,7-dimethyloct-1-ene and butanol which served as a reagent and cosolvent. FT-IR spectra of the activated biochar from CC and CO raw materials showed an absorbance in the range of 1032–1180 cm−1, which is indicative of asymmetric S=O bonds, and the spectra also revealed a band between 3400 and 3700 cm−1, which indicated presence of hydrogen-bonded hydroxyl groups and thus successful activation of the biochar. This observed IR absorbance was absent in the nonactivated biochar. Proximate analysis of upgraded bio-oils revealed a significant reduction in percentage water and oxygen contents, an increase in the high heating value (HHV) and flammability. The chemical composition of the bio-oils was determined using GC-MS, and it showed significant reduction in oxygenated compounds in the upgraded bio-oil as against their high composition in raw bio-oils.

Production of Bio-hydrogen Using Bio-oil as a Potential Biomass-derived Renewable Feedstock

The bio-oil derived from pyrolysis of straw can be selectively converted into high-purity hydrogen by coupling three steps: (i) steam reforming(SR) of different bio-oils, (ii) water-gas shift(WGS), and (iii) the removal of CO2. The catalytic SR reaction over the NiLaTiAl catalyst, coupled with a low-temperature WGS reaction with the CuZnAl catalyst, promoted the conversion of various oxygen-containing organic compounds in the bio-oil into hydrogen and carbon dioxide. Under the optimized condition, light bio-oil achieved the highest conversion(99.8%, molar fraction), with a high hydrogen yield of 16.4%(mass fraction) and a H2 purity of 99.94%(volume fraction). The carbon deposition on the NiLaTiAl catalyst was the main factor caused catalyst deactivation. Production of hydrogen from different bio-oil model compounds was also investigated in detail.

Solar assisted catalytic pyrolysis of chicken-litter waste with in-situ and ex-situ loading of CaO and char

Utilisation of solar energy for thermochemical conversion of biomass can facilitate sustainable development of society by reducing greenhouse gas (GHG) emissions which originate from excessive use of conventional sources of energy. In this work, gas and liquid fuels obtained from solar assisted pyrolysis of chicken-litter waste were upgraded using CaO and char catalysts. The catalysts were loaded in the solar reactor in in-situ and ex-situ modes at different catalyst to biomass ratios. In both cases there was substantial decrease in CO2 accompanied by an increase in the formation of CO and H2 with temperature and catalyst to biomass ratio. The in-situ pyrolysis with 50% CaO loading exhibited maximum CO (63 wt%) and H2 (15 wt%) yields at 800 °C. Similarly, the in-situ pyrolysis with 50% char catalyst produced 60 wt% CO and 5 wt% H2. The addition of CaO exhibited considerable deoxygenation performance for the fatty acids. Minimum concentrations of fatty acids in the liquid product achieved with 50% CaO in the in-situ and ex-situ pyrolysis were 8% and 3%, respectively. On the other hand, the addition of char did not show significant deoxygenation difference for either the alcohols or fatty acids of the bio-oil compounds.

EVALUATION OF DISTILLATION CURVES FOR BIO-OIL OBTAINED FROM THERMAL CRACKING OF WASTE COOKING OIL

ABSTRACT Bio-oil obtained from thermal cracking of waste cooking oil (WCO) is a complex mixture of different chemical compounds and, like crude oil, it is composed mainly of hydrocarbons. The large number of compounds in bio-oil leads to complex and expensive methods for its properties determination. In this study, the distillation curves were constructed for samples of bio-oils obtained from the thermal cracking of WCO in order to predict the properties (such as molecular weight, viscosity and refractive index). Although it is not often employed for bio-oil analyses, the distillation curve method is commonly used in the petroleum industry. Atmospheric and vacuum distillations were performed according to ASTM D86 and ASTM D1160 standards, respectively, for six samples of bio-oil and one sample of crude oil. The results were converted to true boiling point (ASTM D2892) according to the API method (1997) and common petroleum refining correlations were employed. The estimated values for the properties showed little deviation in relation to the experimental data. The bio-oil and crude oil samples contained heavy compounds in their composition, and all samples studied are considered as heavy oils considering the °API range.

Comprehensive study of the liquid products from slow pyrolysis of crambe seeds: Bio-oil and organic compounds of the aqueous phase

The present work addresses the detailed structural elucidation by high resolution techniques of both liquid pyrolysis products from slow pyrolysis of crambe seeds. Bio-oil and aqueous phase were obtained at 400 °C with 32% and 15.8% (w/w) yield and were separated by density difference. Lyophilization was applied to concentrate the organic compounds present in aqueous phase (OCAP). Bio-oil and the OCAP were analyzed by comprehensive bidimensional gas chromatography coupled with time-of-flight mass spectrometry (GC×GC-TOFMS) and positive and negative-ion electrospray (ESI) high resolution Orbitrap mass spectrometry (HRMS). For the bio-oil, 1,400 analytes were identified by GC×GC-TOFMS and the most abundant classes were hydrocarbons (448.6 mg g−1) and N-containing compounds (172.2 mg g−1). In the bio-oil ESI-(+) Orbitrap HRMS data, the N2 class was the most abundant (79.9%). In the negative mode, ca. 87.6% of assigned peaks corresponded to O2 class for bio-oil. The major compounds identified by GC×GC-TOFMS in the OCAP were oxygenated (49.8%) and NO containing compounds (45.9%). ESI (−) Orbitrap HRMS analysis for OCAP presented high percentage of O2 (57.2%) and NO (28.3%) classes, while ESI (+) Orbitrap MS of N2 (51.8%) and NO (28.8%) classes. The aqueous fraction composition profile indicates a potential biological activity due to the presence of N-heterocyclic compounds and the bio-oil (38.9 MJ kg−1; 5.4% H2O) has the potential to be used as a second generation (ASTM D7544) or hydrotreated to improve fuel quality.

Influences of operating parameters on liquefaction performances of Tetra Pak in sub-/supercritical water

Liquefaction performances of waste Tetra Pak in sub-/supercritical water were evaluated in micro-batch reactors. The influences of temperature (300–420 °C), pressure (16–24 MPa), residence time (5–60 min) and feed concentration (5–40 wt%) on bio-oil yield, high heating value (HHV), and functional groups in bio-oil were investigated. The results showed that bio-oil yield firstly increased with increasing temperature and then decreased when the temperature exceeded 360 °C. Reaction time longer than 30 min gave a negative effect on bio-oil yield. The influence of pressure on bio-oil yield increased markedly from 16 MPa to 22 MPa, and then stabilized. The feed concentration higher than 20 wt% showed little influence on bio-oil yield. Maximum bio-oil yield of 35.55% was found at 360 °C, 22 MPa, 30 min and feed concentration of 20 wt%. HHV and energy recovery efficiency increased significantly with temperature, and maximum HHV of 48.747 MJ/kg and energy recovery efficiency of 46.49% were found at 420 °C, 20 MPa, 30 min and feed concentration of 20 wt%. The main compounds in bio-oil and morphology of the solid residue were also analyzed, and the possible liquefaction pathways of Tetra Pak were proposed.

Identification of Bio-oil Compound Utilizing Yeasts Through Phenotypic Microarray Screening

Biomass pyrolysis bio-oil contains a plethora of carbon sources with the potential to be utilized by microorganisms and converted into high value products. However, the majority of these compounds are either highly toxic to microorganisms or are not directly utilizable. Hence research is required to develop methods of separating microbe friendly compounds from inhibitory ones, and to also identify novel microorganisms that can utilise the principal carbon sources in pyrolysis bio-oil. This study employed a phenotypic microarray (PM) technique that measured yeast metabolic output to screen for and shortlist yeast strains able to metabolize various bio-oil carbon sources, with a focus on the anhydrosugar levoglucosan. Four strains of yeast (two Pichia spp. and two Kluyveromyces spp.) were shortlisted due to their high metabolic output (between 79.7 and 113.7 redox signal intensity) on levoglucosan from the PM assay. Under anaerobic fermentation conditions the strains were able to uptake levoglucosan (between 79 and 100% uptake efficiency) but not produce bioethanol; yet trace amounts of acetic acid were generated. This study demonstrated the application of applying the PM technique to screen for novel yeast strains with abilities to metabolize compounds present in pyrolysis bio-oil that could lead to the identification of novel levoglucosan utilization pathways.Graphical

Combined with fractional condensation to upgrade the liquid products derived from the co-pyrolysis of bio-oil distillation residue and bituminous coal

In this study, the effects of induction conditions on the distribution characteristics of graded bio-oil derived from the co-pyrolysis of bio-oil distillation residue and bituminous coal were investigated in a fixed pyrolysis reactor with a three-stage condenser. Based on the central composite design and statistical analysis, it could be found that a quadratic model was recommended to depict the total bio-oil yield, whereas the linear model was the best-fitting model for the graded bio-oil yield of different condensation stages. As for total bio-oil yield, all the combined effects of induction conditions played a negative role, and all second-order effects were advantageous. Moreover, the high percentage of distillation residue contributed to the bio-oil yield at each condenser and had the greatest impact on the bio-oil yield of the first condenser. However, high temperatures and high gas flow rates reduced the bio-oil yield of the first condenser and favored the increase in bio-oil yield of subsequent condensers. In addition, the products derived from distillation residue were more abundant than bituminous coal. And the addition of bituminous coal did not significantly increase the type of compounds in bio-oil from the blends, but disturbed the distribution of bio-oil products. The condensers with different temperatures facilitated the separation and enrichment of different compounds.

Improved conversion of stearic acid to diesel-like hydrocarbons by carbon nanotubes-supported CuCo catalysts

In this study, a novel carbon nanotube (CNT)-supported CuCo catalyst was successfully synthesized by wet impregnation. Experimental and theoretical results on catalytic deoxygenation of stearic acid, a model compound of microalgal bio-oil, revealed that the CuCo catalyst can effectively inhibit cracking reactions and promote production of diesel-like hydrocarbons. CuCo particles in the pores of CNTs were conducive to conversion of stearic acid to long-chain alkanes, featuring a high selectivity of 94.82% at 100% conversion. CuCo catalyst in oxidation state underwent fast in-situ reduction at the beginning of deoxygenation reaction, and its catalytic performance was comparable to that of reduced CuCo catalyst. The improved catalytic conversion of stearic acid to diesel-like hydrocarbons can be achieved at a high ratio of Cu0/(Cu++Cu0) and lattice Co atoms. In addition, the reduced H2 pressure and amounts of catalysts show potential for large-scale industrial applications.

Co-liquefaction of sewage sludge and rice straw/wood sawdust: The effect of process parameters on the yields/properties of bio-oil and biochar products

Liquefaction is a promising technology for the preparation of bio-oil and biochar products from sewage sludge (SS). Co-liquefaction of SS and agricultural/forestry biomass is likely a potential method for obtaining high yield/quality of bio-oil and biochar. In this work, rice straw (RS) and wood sawdust (WS) were selected as representatives of agricultural/forestry biomass and the effects of main process parameters during the co-liquefaction of SS-RS/WS on the yields/properties of bio-oil and biochar were explored in details. The proper reaction temperature, solid-liquid ratio and reaction time for the co-liquefaction of SS-RS/WS were suggested to be 280–300 °C, 0.1 g/mL and 10–30 min, respectively. Potassium/sodium salt (-OH and -CO3) catalysts could efficiently enhanced the co-liquefaction of SS-RS/WS. The introduction of RS/WS into the liquefaction of SS would reduce the contents of nitrogen and sulfur in bio-oil and enhance the formation of phenolic compounds. In addition, co-liquefaction of SS-RS could promote the percentage of lower-boil-point compounds in bio-oil. Although the thermal stability, surface area and pore volume of biochars slightly decreased, the contents of organic matters in biochars were obviously improved, suggesting higher potential in land application.

Synergistic hydrothermal liquefaction of wheat stalk with homogeneous and heterogeneous catalyst at low temperature

The effect of Na2CO3, Fe and Na2CO3 + Fe during hydrothermal liquefaction (HTL) of wheat stalk with different temperature and reaction time was investigated in this study. The results indicated that Na2CO3 + Fe can promote the cracking of wheat stalk compared with Na2CO3 or Fe. Meanwhile, higher temperature favored the decomposition of wheat stalk and formation of heavy bio-oil. The highest heavy bio-oil yield was 24.25 wt% and the maximum liquefaction conversion rate was 89.45 wt% in system of Na2CO3 + Fe at 270 °C. The analysis results indicated that longer reaction time could promote liquefaction conversion especially for heavy bio-oil with Na2CO3 + Fe during the process of HTL. GC–MS, UPLC-MS and FT-IR analysis indicated that the major organic compounds in heavy bio-oil were aromatic compounds, alcohols, ketones, alkanes, and aldehydes, among of them aromatic compounds were the most prevalent.

Thermal characteristics and product formation mechanism during pyrolysis of penicillin fermentation residue

This work studied thermal characteristics and product formation mechanism during pyrolysis of penicillin fermentation residue (PR). Results showed that PR pyrolysis proceeded in four stages. The kinetic triplet of each stage was calculated using Flynn-Wall-Ozawa, Kissinger-Akahira-Sunose, and integral master-plot methods. The kinetic model for stage 1 was the three-dimensional diffusion model, the simple reaction order model for stage 2 and stage 4, and the nucleation-growth model for stage 3. FTIR analysis suggested that the intensities of absorption peaks of NH, CO, CH, CN, and CO in chars weakened gradually with increasing temperature, corresponding to the production of CH4, CO, NH3, and HCN. GC-MS results indicated that the high protein content in PR resulted in a high fraction of nitrogenated compounds (amides and amines, nitriles, and N-heterocyclic species) in bio-oil. The formation mechanism of these compounds was discussed. Besides, bio-oil also contained large quantities of oxygenated compounds and a few hydrocarbons.

Generalized Prediction of Enthalpies of Formation Using DLPNO‐CCSD(T) Ab Initio Calculations for Molecules Containing the Elements H, C, N, O, F, S, Cl, Br

The prediction of thermochemical properties such as enthalpies of formation is of crucial importance, both in research and industrial applications, especially for systems involving not well-characterized molecules, such as biomass systems (bio-oils), or systems involving new compounds (new-generation refrigerants). It is highly desirable to obtain an efficient method by which these values can be predicted. Ab initio-based calculations can be very accurate for predicting gas phase thermochemical properties and are usually more versatile than group contribution methods. In this work, we propose a general extension of the work of Paulechka and Kazakov, using very accurate and efficient domain-based local pair natural orbital-coupled cluster theory ab initio calculations, to determine the enthalpies of formation of a broad variety of molecules. New sets of regressed atomic contributions are proposed for a larger group of elements: H, C, N, O, F, S, Cl, and Br. Excellent predictions are obtained for the most studied compounds (bio-oil compounds and refrigerants). © 2019 Wiley Periodicals, Inc.

Evaluation of bio-oil compounds of catalytic fast pyrolysis by multivariate analysis

Evaluation of bio-oil compounds of catalytic fast pyrolysis by multivariate analysis

Effect of Carbonization on CoMoS Catalyst supports in the Hydrodeoxygenation of Guaiacol as a Model Bio-Oil Compound

CoMoS/Cx/Sup Catalysts were prepared using 12-molybdophosphoric heteropolyacid and cobalt citrate. The supports were Al2O3, SiO2, nos, ZrO2, and carbonized Cr/Sup derived substrates (2 and 6 mass % carbon). The catalytic properties of these samples in the hydrodeoxygenation of guaiacol in a microflow apparatus were studied. With increasing carbon content in the supports, the length and number of MoS2 layers in the package increase in all the samples, apparently due to a decrease in the strength of the particle interaction with the more inert carbonized surface. Furthermore, the dispersion of the molybdenum particles on the catalyst surface, the content of promoter in the CoMoS active phase, and the extent of promotion of the crystallite edges differ significantly. The reasons were examined for the observed behavior and possible activity interrelationship during the hydrodeoxygenation of guaiacol with the parameters of the catalyst and active phase nanoparticles.

Pyrolysis of Crofton weed for the production of aldehyde rich bio-oil and combustible matter rich bio-gas

In this work, the properties of pyrolysis products that obtained from the pyrolysis of Crofton weed was systematically researched. The effect of the different operation factors such as pyrolysis temperature, pyrolysis time, nitrogen flow rate and heating rate on the yields of three products was studied. The results showed that pyrolysis temperature and pyrolysis time have important influence on bio-oil yield, and heating rate has a decisive effect on bio-oil quality. The optimum pyrolysis condition is pyrolysis temperature of the 600 °C, heating rate of 20 °C/min, pyrolysis time of 50 min and nitrogen flow rate of 200 ml/min. The components of bio-oil and bio-gas are characterized by GC–MS and GC under optimum pyrolysis condition, respectively. The main identified compounds of bio-oils were aldehyde, phenol and ketone, corresponding to the contents of the 28.09%, 13.04% and 15.39% of the total area, respectively. Therefore, it can be used as the potential chemical materials in the food, chemical, pharmaceutical and other industries. In addition, Bio-gas mainly contains combustible gases, which accounts for as high as 82.51%. The method of the pyrolysis realizes comprehensive utilization of the Crofton weed.

Hydrodeoxygenation of guaiacol as a model compound of lignin-derived pyrolysis bio-oil over zirconia-supported Rh catalyst: Process optimization and reaction kinetics

To explore the mechanism for hydrodeoxygenation (HDO) of bio-oil, which contains large compounds that share similar molecular structures of phenyl ring with oxygen-containing functional groups, guaiacol as a typical model compound of lignin-derived bio-oil was hydrotreated at 150–350 °C under 3–7 MPa (H2) using the synthesized zirconia-supported Rh catalyst in a batch reactor. With Rh/ZrO2 catalyst, guaiacol can be completely converted where reaction temperature plays a decisive role and significantly affects the degree of hydrogenation. HDO Process was optimized with insight into effects of different reaction parameters, including H2 pressure, reactant concentration, reaction time and temperature, on the whole process of HDO and formation of undesired oxygen-contained products. The optimum reaction conditions were 5 wt. % guaiacol, 300 °C and 7 MPa in which guaiacol could be completely deoxygenated with 87. 7 mol% oxygen-free product of cyclohexane in 3 h and the desired O/C and H/C ratios of products were obtained. A specific reaction network including three main steps: “guaiacol → 1-methyl-1,2-cyclohexanediol → cyclohexanone and cyclohexanol → completely deoxygenated compounds of cycloalkanes”, was deduced by a comprehensive study on different reaction parameters and a typical key reaction network for HDO of lignin-derived bio-oil is proposed based on model compounds studies. Kinetic model for HDO of guiaacol with the Rh/ZrO2 catalyst was proposed based on the credible pathway and it fits well to a pseudo-first-order kinetic model that the R2 values obtained for the fittings were all above 0.98 at four temperatures. At low temperature of 150 °C, the kinetically relevant step is hydrogenation of the aromatic ring, yielding 90 mol% 1-methyl-1,2-cyclohexanediol, while at high temperature (≥300 °C), the kinetically relevant step is the complete deoxygenation of oxygen-containing functional groups which mainly yields cyclohexane. These results would be helpful to further understand the HDO mechanism of lignin-derived bio-oil, and the excellent performance of Rh/ZrO2 demonstrated its potential application in bio-oil hydrodeoxygenative upgrading process.

Production of phenolic compounds using waste coir pith: Estimation of kinetic and thermodynamic parameters

The present study illustrates the production of phenolic compounds via slow pyrolysis of coir pith biomass in a bench-scale reactor. The primary objective of the study is to optimize the pyrolysis conditions to maximize the yield of bio-oil and phenolic compounds. Up to 88.14% phenolic compounds were obtained in the organic fraction of the bio-oil obtained at 350 °C. The phenolic compounds thus extracted can be used for the production of phenol-formaldehyde resins, which reduces the dependence on petroleum-based phenols for the manufacturing of resin. An independent kinetic analysis of the apparent pyrolysis reaction was also performed using thermogravimetry and isoconversional methodology. The calculated values of activation energy showed a variation from 28.41 to 200.09 kJ/mol, with the mean value being 140 kJ/mol. The thermodynamic parameters (ΔS, ΔH, and ΔG) were subsequently evaluated at different conversions using the activation energy values obtained from the kinetic analysis.