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Joonweon Choi - One of the best experts on this subject based on the ideXlab platform.
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investigation of physicochemical properties of biooils produced from yellow Poplar Wood liriodendron tulipifera at various temperatures and residence times
Journal of Analytical and Applied Pyrolysis, 2011Co-Authors: Kwang Ho Kim, Ingyu Choi, Soo-min Lee, Hwanmyeong Yeo, In Yong Eom, Donha Choi, Joonweon ChoiAbstract:Abstract Fast pyrolysis of yellow Poplar Wood ( Liriodendron tulipifera ) was performed under different temperature ranges and residence times in a fluidized bed reactor to maximize the yield of biooil. In this study, the pyrolysis temperature ranged from 400 °C to 550 °C, and the residence time of pyrolysis products was controlled between 1.2 and 7.7 s by inert nitrogen gas flow. The results revealed that the distribution of thermal degradation products (biooil, biochar, and gas) from the Woody biomass was heavily influenced by pyrolysis temperature, as well as residence time. The highest yield of biooil was approximately 68.5 wt% (wet basis), with pyrolysis conditions of 500 °C and 1.9 s of residence time. Water content of the biooils produced at different temperatures was 25–30 wt%, and their higher heating values were estimated to be between 15 MJ/kg and 17 MJ/kg. Using GC/MS analysis, 30 chemical components were identified from the biooil, which were classified into 5 main groups: organic acids, aldehydes, ketones, alcohols, and phenols. In addition, biochar was produced as a co-product of fast pyrolysis of Woody biomass, approximately 10 wt%, at temperatures between 450 °C and 550 °C. The physicochemical features of the biochar, including elemental analysis, higher heating values, and morphological properties by SEM, were also determined.
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characterization of lignin rich residues remaining after continuous super critical water hydrolysis of Poplar Wood populus albaglandulosa for conversion to fermentable sugars
Bioresource Technology, 2011Co-Authors: Sunjoo Moon, Ingyu Choi, Soo-min Lee, In Yong Eom, Jaeyoung Kim, Taeseung Kim, Joonweon ChoiAbstract:Abstract Poplar Wood flour ( Populous albaglandulosa ) was treated with sub- and super-critical water (subcritical: 325, 350 °C; super-critical: 380, 400, 425 °C) for 60 s at 220 ± 10 atm. Hydrochloric acid (0.05% v/v) was added to samples as acidic catalyst. The final products were separated into water soluble fraction and undegraded solids. The yields of undegraded solids were thoroughly dependent on temperature severity and mainly composed of lignin fragments. Average molecular weights of the lignins were between 1500 and 4400 Da, which was only 1/3–1/8-fold of Poplar milled Wood lignin (13,250 Da). DFRC ( Derivatization Followed by Reductive Cleavage ) analysis revealed that C6C3 phenols (coniferyl and sinapyl alcohol) were rarely detected in the lignins, indicating occurrence of two probable lignin reactions during SCW hydrolysis: lignin fragmentation via splitting of β-O-4 linkage and loss of propane side chains. These results were also confirmed by 1 H and 13 C NMR spectroscopic analysis.
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characterization of by products from organosolv pretreatments of yellow Poplar Wood liriodendron tulipifera in the presence of acid and alkali catalysts
Journal of Industrial and Engineering Chemistry, 2011Co-Authors: Bonwook Koo, Joonweon Choi, Hwanmyeong Yeo, Nahyun Park, Hanseob Jeong, Ingyu ChoiAbstract:Abstract Characterization of by-products generated during organosolv pretreatments of yellow Poplar Wood was performed in the presence of sulfuric acid and sodium hydroxide catalysts to elucidate the effects on further biological fermentation and provide the preliminary data for utilization of organosolv lignin. Monomeric sugars contents were 2.2–7.7% in organosoluble fraction with acid catalyst, while significantly lower amount of sugars (0.2–0.3%) were determined in that of with alkali catalyst. However, the concentrations of monomeric sugars were very low to ferment directly. Therefore, the oligomeric sugars in organosoluble fraction should be recovered to improve the economic feasibility of the organosolv pretreatment. Higher concentrations of inhibitory compounds such as acetic acid, 5-HMF and furfural were determined in the organosoluble fraction with acid catalyst. However, the concentrations were lower than the minimum inhibitory concentration to the microorganism for further biological process regardless of catalyst. Thus, the compounds could not inhibit the biological fermentation of organosoluble fraction. Precipitates, solid by-products, were also characterized by diverse analytical methods and the analysis results revealed that the precipitates were mostly composed of lignin polymers regardless of catalyst. However, the structures could be slightly modified during pretreatment and mixed with come carbohydrates by chemical bonds and/or physical association.
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saccharification of lignocellulosics by supercritical water
New & Renewable Energy, 2006Co-Authors: Joonweon Choi, Hyunjin Lim, Gyusung Han, Donha ChoiAbstract:To characterize thermo-chemical feature of sugar conversion of Woody biomass, Poplar Wood () powder was treated with supercritical water system. Supercritical water treatment (SCWT) was performed for 60 seconds at different temperatures (subcritical zone 350; supercritical zone ) under two pressures as well as , respectively, using flow type system. After separation of solid residues from SCWT products, the monomeric sugars in aqueous part converted from Poplar Wood powder were quantitatively determined by high performance anionic exchange chromatography [HPAEC] equipped with PAD detector and Carbo Pac PA10 column. As the temperature treated increased, the degradation of Poplar Wood powder was enhanced and ca 83% of Woody biomass was dissolved into the water at . However, the pressure didn't help the degradation of biomass components. At subcritical temperature range, xylose was first formed by degradation of xylan, which is main hemicellulose component in hardWood species, while cellulose degradation started at the transition zone between sub and supercritical conditions and was remarkably accelerated at the supercritical temperature. In the supercritical water system the maximum yield of monomeric sugars amounts to ca. 7.3% based on oven dried Wood weight at .
Changqing Dong - One of the best experts on this subject based on the ideXlab platform.
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selective production of levoglucosenone from catalytic fast pyrolysis of biomass mechanically mixed with solid phosphoric acid catalysts
Bioenergy Research, 2015Co-Authors: Zhibo Zhang, Tipeng Wang, Xianhua Wang, Changqing DongAbstract:Solid phosphoric acid (SPA) catalysts with different carriers were prepared and used for catalytic fast pyrolysis of Poplar Wood to produce levoglucosenone (LGO), a valuable anhydrosugar derivative that can be used in various organic synthesis applications. Pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) experiments were performed to evaluate the catalytic capabilities of these catalysts under different reaction conditions. The results indicated that SPA catalyst prepared with the SBA-15 carrier exhibited the best catalytic capability for selectively producing LGO. Both the catalytic pyrolysis temperature and catalyst-to-biomass ratio affected the pyrolytic products greatly. The maximal LGO yield reached as high as 8.2 wt% from Poplar Wood, obtained at the pyrolysis temperature of 300 °C and the catalyst-to-biomass ratio of 1. The by-products during the catalytic pyrolysis process were mainly acetic acid (AA) and furfural (FF). In addition, the SPA catalyst possessed better catalytic capability than the liquid phosphoric acid (H3PO4) catalyst to produce LGO.
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catalytic fast pyrolysis of cellulose and biomass to produce levoglucosenone using magnetic so42 tio2 fe3o4
Bioresource Technology, 2014Co-Authors: Zhibo Zhang, Changqing Dong, Ying ZhangAbstract:Magnetic superacid (SO4(2-)/TiO2-Fe3O4) was prepared for catalytic fast pyrolysis of cellulose and Poplar Wood to produce levoglucosenone (LGO). Its catalytic activity was evaluated via pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) experiments, and compared with the non-magnetic SO4(2-)/TiO2, phosphoric acid (H3PO4) and sulfur acid (H2SO4) catalysts. Moreover, the LGO yield was quantitatively determined. The results indicated that the magnetic SO4(2-)/TiO2-Fe3O4 was effective to selectively produce LGO from both cellulose and Poplar Wood. Its catalytic capability was a little better than the non-magnetic SO4(2-)/TiO2 and H3PO4, and much better than the H2SO4. The maximal LGO yields from both cellulose and Poplar Wood were obtained at 300 °C with the feedstock/catalyst ratio of 1/1, reaching as high as 15.43 wt% from cellulose and 7.06 wt% from Poplar Wood, respectively.
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catalytic fast pyrolysis of biomass impregnated with k3po4 to produce phenolic compounds analytical py gc ms study
Journal of Analytical and Applied Pyrolysis, 2013Co-Authors: Zhibo Zhang, Changqing Dong, Xiaochu Yang, Xifeng ZhuAbstract:Abstract A new technique was proposed to produce phenolic-rich bio-oil from catalytic fast pyrolysis of biomass impregnated with K 3 PO 4 . In this study, analytical pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) experiments were performed to investigate the K 3 PO 4 -catalyzed biomass pyrolysis process, mainly using Poplar Wood as the feedstock. The results indicated that the presence of K 3 PO 4 would inhibit the devolatilization of holocellulose to form organic volatile compounds, and meanwhile promote the decomposition of lignin to form phenolic compounds (mainly the phenol and 2,6-dimethoxy phenol from Poplar Wood). With the increasing of the K 3 PO 4 content, the yield of the total phenolic compounds was firstly increased and then decreased, while their total content was increased steadily. The maximal phenolics yield was obtained at around 7.42 wt% K 3 PO 4 , with the peak area% of 42.8%. Whereas the maximal phenolics peak area% was over 60% at high K 3 PO 4 content.
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characteristics and mechanism study of analytical fast pyrolysis of Poplar Wood
Energy Conversion and Management, 2012Co-Authors: Changqing Dong, Zhifei Zhang, Yongping YangAbstract:Abstract Analytical pyrolysis–gas chromatography/mass spectrometry (Py–GC/MS) was applied to achieve fast pyrolysis of Poplar Wood and on-line analysis of the pyrolysis vapors. Experiments were conducted to reveal the distribution of pyrolytic products under different pyrolysis temperatures (300–1000 °C) and times (5–30 s). During the fast pyrolysis process, the Poplar Wood started decomposition to form organic volatile products at the set temperature of 300 °C, and reached the maximum volatile product yield at around 550 °C. The products included various anhydrosugars, furans, phenolic compounds, linear carbonyls, linear acids, hydrocarbons, and so on. They exhibited different formation characteristics. Based on the experimental results, we discussed the possible pyrolytic pathways for the generation of the major products.
Ingyu Choi - One of the best experts on this subject based on the ideXlab platform.
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investigation of physicochemical properties of biooils produced from yellow Poplar Wood liriodendron tulipifera at various temperatures and residence times
Journal of Analytical and Applied Pyrolysis, 2011Co-Authors: Kwang Ho Kim, Ingyu Choi, Soo-min Lee, Hwanmyeong Yeo, In Yong Eom, Donha Choi, Joonweon ChoiAbstract:Abstract Fast pyrolysis of yellow Poplar Wood ( Liriodendron tulipifera ) was performed under different temperature ranges and residence times in a fluidized bed reactor to maximize the yield of biooil. In this study, the pyrolysis temperature ranged from 400 °C to 550 °C, and the residence time of pyrolysis products was controlled between 1.2 and 7.7 s by inert nitrogen gas flow. The results revealed that the distribution of thermal degradation products (biooil, biochar, and gas) from the Woody biomass was heavily influenced by pyrolysis temperature, as well as residence time. The highest yield of biooil was approximately 68.5 wt% (wet basis), with pyrolysis conditions of 500 °C and 1.9 s of residence time. Water content of the biooils produced at different temperatures was 25–30 wt%, and their higher heating values were estimated to be between 15 MJ/kg and 17 MJ/kg. Using GC/MS analysis, 30 chemical components were identified from the biooil, which were classified into 5 main groups: organic acids, aldehydes, ketones, alcohols, and phenols. In addition, biochar was produced as a co-product of fast pyrolysis of Woody biomass, approximately 10 wt%, at temperatures between 450 °C and 550 °C. The physicochemical features of the biochar, including elemental analysis, higher heating values, and morphological properties by SEM, were also determined.
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characterization of lignin rich residues remaining after continuous super critical water hydrolysis of Poplar Wood populus albaglandulosa for conversion to fermentable sugars
Bioresource Technology, 2011Co-Authors: Sunjoo Moon, Ingyu Choi, Soo-min Lee, In Yong Eom, Jaeyoung Kim, Taeseung Kim, Joonweon ChoiAbstract:Abstract Poplar Wood flour ( Populous albaglandulosa ) was treated with sub- and super-critical water (subcritical: 325, 350 °C; super-critical: 380, 400, 425 °C) for 60 s at 220 ± 10 atm. Hydrochloric acid (0.05% v/v) was added to samples as acidic catalyst. The final products were separated into water soluble fraction and undegraded solids. The yields of undegraded solids were thoroughly dependent on temperature severity and mainly composed of lignin fragments. Average molecular weights of the lignins were between 1500 and 4400 Da, which was only 1/3–1/8-fold of Poplar milled Wood lignin (13,250 Da). DFRC ( Derivatization Followed by Reductive Cleavage ) analysis revealed that C6C3 phenols (coniferyl and sinapyl alcohol) were rarely detected in the lignins, indicating occurrence of two probable lignin reactions during SCW hydrolysis: lignin fragmentation via splitting of β-O-4 linkage and loss of propane side chains. These results were also confirmed by 1 H and 13 C NMR spectroscopic analysis.
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characterization of by products from organosolv pretreatments of yellow Poplar Wood liriodendron tulipifera in the presence of acid and alkali catalysts
Journal of Industrial and Engineering Chemistry, 2011Co-Authors: Bonwook Koo, Joonweon Choi, Hwanmyeong Yeo, Nahyun Park, Hanseob Jeong, Ingyu ChoiAbstract:Abstract Characterization of by-products generated during organosolv pretreatments of yellow Poplar Wood was performed in the presence of sulfuric acid and sodium hydroxide catalysts to elucidate the effects on further biological fermentation and provide the preliminary data for utilization of organosolv lignin. Monomeric sugars contents were 2.2–7.7% in organosoluble fraction with acid catalyst, while significantly lower amount of sugars (0.2–0.3%) were determined in that of with alkali catalyst. However, the concentrations of monomeric sugars were very low to ferment directly. Therefore, the oligomeric sugars in organosoluble fraction should be recovered to improve the economic feasibility of the organosolv pretreatment. Higher concentrations of inhibitory compounds such as acetic acid, 5-HMF and furfural were determined in the organosoluble fraction with acid catalyst. However, the concentrations were lower than the minimum inhibitory concentration to the microorganism for further biological process regardless of catalyst. Thus, the compounds could not inhibit the biological fermentation of organosoluble fraction. Precipitates, solid by-products, were also characterized by diverse analytical methods and the analysis results revealed that the precipitates were mostly composed of lignin polymers regardless of catalyst. However, the structures could be slightly modified during pretreatment and mixed with come carbohydrates by chemical bonds and/or physical association.
Bin Yang - One of the best experts on this subject based on the ideXlab platform.
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characterization of lignin derived from water only and dilute acid flowthrough pretreatment of Poplar Wood at elevated temperatures
Biotechnology for Biofuels, 2015Co-Authors: Libing Zhang, Lishi Yan, Zheming Wang, Dhrubojyoti D Laskar, Marie Swita, John R Cort, Bin YangAbstract:Flowthrough pretreatment of biomass is a critical step in lignin valorization via conversion of lignin derivatives to high-value products, a function vital to the economic efficiency of biorefinery plants. Comprehensive understanding of lignin behaviors and solubilization chemistry in aqueous pretreatment such as water-only and dilute acid flowthrough pretreatment is of fundamental importance to achieve the goal of providing flexible platform for lignin utilization. In this study, the effects of flowthrough pretreatment conditions on lignin separation from Poplar Wood were reported as well as the characteristics of three sub-sets of lignin produced from the pretreatment, including residual lignin in pretreated solid residues (ReL), recovered insoluble lignin in pretreated liquid (RISL), and recovered soluble lignin in pretreatment liquid (RSL). Both the water-only and 0.05 % (w/w) sulfuric acid pretreatments were performed at temperatures from 160 to 270 °C on Poplar Wood in a flowthrough reactor system for 2–10 min. Results showed that water-only flowthrough pretreatment primarily removed syringyl (S units). Increased temperature and/or the addition of sulfuric acid enhanced the removal of guaiacyl (G units) compared to water-only pretreatments at lower temperatures, resulting in nearly complete removal of lignin from the biomass. Results also suggested that more RISL was recovered than ReL and RSL in both dilute acid and water-only flowthrough pretreatments at elevated temperatures. NMR spectra of the RISL revealed significant β-O-4 cleavage, α-β deoxygenation to form cinnamyl-like end groups, and slight β-5 repolymerization in both water-only and dilute acid flowthrough pretreatments. Elevated temperature and/or dilute acid greatly enhanced lignin removal to almost 100 % by improving G unit removal besides S unit removal in flowthrough system. Only mild lignin structural modification was caused by flowthrough pretreatment. A lignin transformation pathway was proposed to explain the complexity of the lignin structural changes during hot water and dilute acid flowthrough pretreatment.
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enhancement of total sugar and lignin yields through dissolution of Poplar Wood by hot water and dilute acid flowthrough pretreatment
Biotechnology for Biofuels, 2014Co-Authors: Lishi Yan, Libing Zhang, Bin YangAbstract:Pretreatment is a vital but expensive step in biomass biofuel production. Overall, most of this past effort has been directed at maximizing sugar yields from hemicellulose and cellulose through trials with different chemicals, operating conditions, and equipment configurations. Flowthrough pretreatment provides a promising platform to dissolution of lignocellulosic biomass to generate high yields of fermentable sugars and lignin for biofuels productions. Dissolution of xylan, lignin, and cellulose from Poplar Wood were significantly enhanced by water-only and dilute acid (0.05% w/w, H2SO4) flowthrough pretreatment when the temperature was raised from 200°C to 280°C over a range of flow rates 10-62.5 mL/min, resulting in more than 98% solid removal. Up to 40% of original xylan was converted to xylose in the hydrolyzate and the rest xylan was solubilized into xylooligomers with negligible furfural formation. Up to 100% cellulose was removed into hydrolyzate with the highest glucose yield of 60% and low 5-hydroxymethylfurfural (5-HMF) formation. The maximal recovered insoluble lignin and soluble lignin were 98% and 15% of original lignin, respectively. In addition, enzymatic hydrolysis of pretreated whole slurries was characterized under various enzyme loadings with or without Bovine serum albumin (BSA) treatment. More than 90% glucose yield and 95% xylose yield were obtained from enzymatic hydrolysis of dilute acid pretreated whole slurries with 10 mg protein Ctec 2 with 2 mg Htec2/g glucan + xylan. Nearly complete dissolution of whole biomass was realized through water-only and dilute acid flowthrough pretreatment under tested conditions. Temperature was considered as the most significant factor for cellulose degradation. The cellulose removal significantly increased as temperature reached 240°C for water-only and 220°C for dilute acid. Dilute acid pretreatment resulted in higher yields of recovered xylan and cellulose as monomeric sugars in the hydrolyzate than that for water-only pretreatment. Enzymes readily hydrolyzed the degraded cellulose and xylooligomers in pretreatment hydrolysate. Results suggested that kinetics controlled the flowthrough pretreatment of biomass dissolution, which was also affected by flow rate to certain extent.
Runcang Sun - One of the best experts on this subject based on the ideXlab platform.
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synergistic benefits of ionic liquid and alkaline pretreatments of Poplar Wood part 1 effect of integrated pretreatment on enzymatic hydrolysis
Bioresource Technology, 2013Co-Authors: Tongqi Yuan, Wei Wang, Runcang SunAbstract:An environmentally friendly pretreatment process was developed to fractionate hemicelluloses and lignin from Poplar Wood by ionic liquid (IL) pretreatment coupled with mild alkaline extraction. Hemicellulosic and lignin fractions were obtained in high yields, amounting to 59.3% and 74.4%, respectively, which can served as raw materials for production of value-added products. The yield of glucose for the integrated pretreated Poplar Wood was 99.2%, while it was just 19.2% for the untreated material. The synergistic benefits of the removal of lignin and hemicelluloses, the increase of the cellulose surface area, and the conversion of cellulose fibers from the cellulose I to the cellulose II crystal phase resulted in the high glucose yield for the integrated pretreated substrate. Therefore, the IL based biorefining strategy proposed can integrate biofuels production into a biorefinery scheme in which the major components of Poplar Wood can be converted into value-added products.
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isolation and physico chemical characterization of lignins from ultrasound irradiated fast growing Poplar Wood
Bioresources, 2011Co-Authors: Tongqi Yuan, Shaoni Sun, Runcang SunAbstract:Ultrasonic irradiation with organic solvents and alkaline extractions were carried out on a fast-growing Poplar Wood, triploid of Populus tomentosa Carr., in an attempt to develop efficient lignin isolation procedures. Four organosolv and three alkaline lignin fractions were successively isolated and comparatively characterized by sugar analysis, alkaline nitrobenzene oxidation, gel permeation chromatography (GPC), Fourier transform infra-red spectroscopy (FT-IR), quantitative 13C, and 2D HSQC nuclear magnetic resonance (NMR) spectroscopy, as well as thermogravimetric analysis (TGA). The results showed that the ultrasonic treatments and sequential extractions with three different concentrations of NaOH led to a release of 90.9% of the original lignin. The four organosolv lignin preparations obtained under the ultrasound-assisted extractions were degraded significantly and contained more carbohydrate and non-condensed syringyl units when compared to the three alkaline lignin preparations. Furthermore, the analyses confirmed that L5, the lignin preparation with the highest yield (44.6% of the original lignin), was partially acylated at the γ-carbon of the side-chain preferentially over syringyl units. The percentage of lignin acylation of β-O-4’ linkages was about 14%. The amount of β-O-4’, β-β’, and –OCH3 were estimated to be about 0.31/Ar, 0.06/Ar, and 1.73/Ar, respectively. The ratio of S/G was calculated to be 2.0.
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ester and ether linkages between hydroxycinnamic acids and lignins from wheat rice rye and barley straws maize stems and fast growing Poplar Wood
Industrial Crops and Products, 2002Co-Authors: Runcang Sun, X F Sun, S Q Wang, W Zhu, X Y WangAbstract:Abstract Treatment of solvent extracted wheat, rice, rye, and barley straws, maize stems, and fast-growing Poplar Wood with 60% aqueous ethanol in 0.2 M HCl at 75 °C for 3 h released 51.8, 51.2, 47.2, 43.7, 54.0, and 16.7% of the original lignin, and 44.3, 50.3, 30.9, 36.1, 40.0, and 25.5% of the original hemicelluloses, respectively. It was found that the bulk of p-coumaric acid (PCA) (67.0–83.5%) was esterified at the lignin side chains, while ferulic acid (FA) is linked to lignin side chains through both ether bonds (51.6–68.3%) and ester bonds (31.7–48.4%), indicating that FA may form intra- and/or inter-molecular ester–ether bridges between lignin fragments, which is first proposed in this study. In addition to p-hydroxybenzoic acid esterified to lignins in the cell walls of wheat straw and fast-growing Poplar Wood, a small portion of ether-linked p-hydroxybenzoic acid in the lignin preparations, obtained from rice, rye, and barley straws and maize stems, was also detected. It was also detected that noticeable amounts of syringic and vanillic acids were predominantly esterified to the lignin molecules in the cell walls of the materials studied.
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fractional isolation and physico chemical characterization of alkali soluble lignins from fast growing Poplar Wood
Polymer, 2000Co-Authors: Runcang Sun, J Tomkinson, X F Sun, N J WangAbstract:Abstract This paper examines the physico-chemical properties and structural features of six alkali-soluble lignin preparations extracted with 5, 7.5, and 10% NaOH at 50°C for 4–12 h from fast-growing Poplar Wood. The pure lignin (PL) preparations were characterized using UV, FT-IR, 13 C-NMR, GPC, and alkaline nitrobenzene oxidation methods. The results showed that all the PL fractions are relatively free of associated polysaccharides and are composed of large amounts of syringyl units together with noticeable quantities of guaiacyl and fewer p -hydroxyphenyl units. Their weight-average molecular weights ranged from 4520 to 6900 g mol −1 . Noticeable amounts of esterified p -hydroxybenzoic acids, minor quantities of esterified p -coumaric acid, and traces of both ester and ether linked ferulic acids were identified in the isolated lignin preparations. The lignin fraction, extracted with 5% NaOH at 50°C for 12 h from the dewaxed fast-growing Poplar Wood, is composed mainly of β- O -4 ether bonds together with small amounts of β–β′ and β-5 carbon–carbon linkages between the lignin structural units.