FUEL PROCESSING TECHNOLOGY
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2022
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IF 8.129
Weitao Wang,Yan Ma,Guoxing Chen,Cui Quan,Jale Yanik,Ningbo Gao,Xin Tu
Converting biomass into energy and fuels is considered a promising strategy for replacing the exhaustible fossil fuels. In this study, we report on a tandem process that combines cellulose pyrolysis and plasma-assisted reforming for H 2 production. The hybrid pyrolysis/plasma reforming process was carried out in a two-stage reaction system incorporating a coaxial dielectric barrier discharge (DBD) plasma reactor. The effects of discharge power, steam, reforming temperature, and catalyst on the reaction performance were investigated. The results show that low temperatures are preferred in the non-catalytic plasma reforming process, whereas high temperatures are desired to achieve a high H 2 yield and a high H 2 selectivity in the plasma-catalytic reforming system. The synergistic effect of plasma catalysis was dominant in the plasma-catalytic reforming process at 250 °C. In contrast, the catalyst, rather than the plasma, played a dominant role in the plasma-catalytic reforming at higher temperatures (550 °C). Using Ni-Co/Al 2 O 3 at a reforming temperature of 550 °C, a high H 2 yield of 26.6 mmol/g was attainted, which was more than 8 times and about 100% greater than that obtained using plasma alone and catalyst alone, respectively. This work highlights the potential of non-thermal plasmas in low-temperature biomass conversion.
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高影响因子
FUEL PROCESSING TECHNOLOGY
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2022
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IF 8.129
Lei Wang,Mengdi Liang,Yang Fang,Jun Yin,Jungang Jiang,Yifan Zhang,Haiping Yang
Understanding the pyrolysis mechanism of native lignin is essential for improving the conversion efficiency of fast pyrolysis technology. However, due to the complex and various nature of lignin interunit linkages, the pyrolysis mechanism of lignin has not been clearly revealed so far, especially for native lignin. In this work, two types of guaiacyl-dehydrogenation polymers (G-DHPs) were synthesized using two different methods in vitro , namely endwise polymerization (G-DHPs-endwise) and bulk polymerization (G-DHPs-bulk), which were used as native lignin models. The chemical structures of the synthesized G-DHPs along with natural G-lignin ( i.e., milled wood lignin, MWL) were analyzed by using 2D HSQC NMR, and their pyrolysis characteristics were investigated by using a fixed bed reactor . In comparison with G-DHPs-bulk, G-DHPs-endwise had more similar structure and pyrolysis characteristics with that of MWL, which suggested that G-DHPs-endwise was a more suitable model for G-type lignin. Further mechanical study revealed that the pyrolysis of G-DHPs-endwise underwent an end-breaking pathway, by which the branched carbon of the coniferyl alcohol structure ends were cleaved at the early stage to depolymerize into guaiacol . This study can thus enhance the understanding of the thermal depolymerization of native lignin and provide the evidence for revealing pyrolysis mechanism.
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高影响因子
Journal of Environmental Chemical Engineering
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2022
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IF 7.968
Mengjiao Fan,Chao Li,Yuewen Shao,Kai Sun,Lijun Zhang,Shu Zhang,Kuan Ding,Mortaza Gholizadeh,Xun Hu
In pyrolysis , the formed biochar is not an inert material as it could interact with of varied volatiles via distinct ways, modifying the composition of bio-oil and its own property. In this study, the pyrolysis of biomass with the biochar of the exactly same origin was conducted at 500 ºC with cellulose, lignin and poplar sawdust as the research objects, aiming to probe the potential involvement of biochar in pyrolysis. It has been demonstrated that, independent of feedstock, the presence of biochar decreased yields of newly formed biochar (41.0 % decrease for cellulose while 22.3 % for sawdust) via suppressing secondary condensation of volatiles. However, the biochar catalyst aided to form more bio-oil and gas via catalyzing the secondary cracking reactions such as decarboxylation and dehydrogenation reactions. In addition, during the volatile-char interaction, deposition of oxygen-containing species on surface of biochar was observed, which influenced the thermal stability, hydrophilicity, the crystallinity and regularity of the spatial arrangement of carbon crystals of the resulting biochar. The results from in-situ characterization showed that the biochar catalyst interfered with the dehydrogenation of the C-H, the dehydration of -OH and formation of the reaction intermediates with C O.
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高影响因子
FUEL PROCESSING TECHNOLOGY
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2022
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IF 8.129
Yuan Liu,Shiliang Wu,Huiyan Zhang,Rui Xiao
A novel valorization pathway for steam-exploded corn stalk conversion to long-chain ethers was proposed in the work. The procedure enabled the transformation of multifunctional components in catalytic fast pyrolysis (CFP) vapors using Fe-Ce mixed oxides into carbonyl compounds (ketones, aldehydes and furans with carbonyl group) suitable for preparing long-chain oxygenated fuels in a fluidized-bed/fixed-bed consolidation reactor. A series of Fe-Ce bimetallic oxides were explored and the results indicated that the catalyst with 0.3 of molar ratio of Fe to Ce (Fe/Ce(0.3)) showed highly active in converting levoglucosan and acetic acid into linear and cyclic ketones . Moreover, the conversion rate of acetic acid and levoglucosan in pyrolytic vapors was close to 100% and 90.07%, respectively. The carbon yield of carbonyl compounds (28.91%) in ex-situ CFP was achieved under optimal conditions. The continuous operation showed that Fe/Ce(0.3) remained highly active and there was little coke and carboxylates on the catalyst surface after 200 min.
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高影响因子
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
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2022
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IF 6.437
Bo Wang,Kai Li,Dong-hong Nan,Shi-yu Feng,Bin Hu,Ti-peng Wang,Qiang Lu
A new method was developed for the selective production of levoglucosenone (LGO) from catalytic pyrolysis of waste paper. Copy paper (CP) was selected as the representative waste paper and subjected to single or combined pretreatment with ethanol and HCl solutions. The influences of pretreatment method, acid concentration, and pretreatment temperature were systematically investigated to reveal their impacts on the physicochemical properties and pyrolytic characteristics of CP as well as LGO formation. The catalytic pyrolysis experiments of pretreated CP were conducted using pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) and lab-scale device under different pyrolysis temperatures and sample/catalyst ratios. The results showed that the combined ethanol-HCl pretreatment was the most conducive to LGO production, with the optimal pretreatment conditions of acid concentration of 23% and pretreatment temperature of 80 °C. With phosphoric acid-activated carbon (PAC) as the catalyst, the maximum yields of LGO reached 18.15 wt% and 14.76 wt% at 260 °C from Py-GC/MS and lab-scale experiments with sample/catalyst ratios of 4 and 5, respectively. Compared with cellulose and biomass materials, catalytic pyrolysis of pretreated CP had the advantages of high LGO yield and low production temperature.
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高影响因子
RENEWABLE ENERGY
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2022
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IF 8.634
Lingyan Zhu,Xudong Liu,Yuan Wu,Qifan Wang,Haotian Wang,Dongbing Li
Lignin-based activated carbons (LAC) were produced using thermochemical pretreatment and chemical activation with KOH. Fast pyrolysis at 550 °C in a CO 2 /N 2 atmosphere resulted in lignin char (LC) with a more developed porous structure than slow pyrolysis. The effect of activation conditions (KOH usage, temperature, and duration) on surface/physicochemical properties and electrochemical characteristics of the resulting LAC was fully studied. Using fast pyrolysis lignin char as a precursor and optimized activation conditions ( w KOH : w LC = 2, 800 °C, and 2 h), the resulting LAC featured a large surface area of 2149.5 m 2 g −1 , a total pore volume of 0.88 m 3 g −1 , and high capacitance of 300 F g −1 at 0.5 A g −1 in a 6 mol L −1 KOH electrolyte. The LAC-based symmetric supercapacitor could offer superior energy density (19.15 W h kg −1 at 250 W kg −1 power density) and a stable lifetime (98.2% of original capacity after 10,000 charge-discharge cycles). The excellent capacitor performance of LAC was attributed to its microporous-mesoporous structure developed from fast pyrolysis and subsequent chemical activation.
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高影响因子
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
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2022
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IF 6.437
Haoran Yuan,Chengyu Li,Rui Shan,Jun Zhang,Lingjun Zhu,Yong Chen
In the present study, a series of municipal sludge derived solid acids, synthesized through hydrothermal pre-carbonization coupled with secondary pyrolysis method, were developed for levoglucosenone (LGO) production via cellulose fast pyrolysis . Specific physico-chemical characterizations such as XRD, FTIR, N 2 adsorption-desorption, NH 3 -TPD, etc., were undertaken to reveal the structural properties of as-prepared solid acids. Phosphoric acid and sulfuric acid decorated municipal sludge derived carbon-based materials containing abundant Brønsted acid sites remarkably facilitated the selective formation of LGO. Particularly, high LGO yield (~20 wt%) were achieved using both phosphoric and sulfonic acid functionalized municipal sludge derived porous carbon. The as-prepared municipal sludge derived solid acids could be reused for multiple cycles in LGO preparation without significant decline in pyrolysis performance. This research will provide good reference for the resource utilization of lignocellulosic biomass and municipal sludge, particularly in the aspect of valuable chemicals manufacture.
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高影响因子
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
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2020
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IF 3.905
Qingguo Zhou,Zhongyang Luo,Guoxiang Li,Simin Li
Lignin pyrolysis is a promising method for the sustainable production of phenolic compounds from biomass. However, detailed knowledge about the radicals involved in this process and their influence during the coking is missing. Herein, we report on the pyrolysis of guaiacol, a lignin monomer at 600 °C under inert and hydrogen gas conditions. During the pyrolysis process, the formed radicals were detected by two improved electron paramagnetic resonance spectroscopy methods. Successfully observed o-phenyl semiquinone radical anion, cyclopentadienyl radical, methyl radical, hydroxyl radical, methoxy radical, phenyl radical, phenoxy radical, etc. during the pyrolysis of guaiacol, as well as the changes of related radicals in different pyrolysis stages. It was found that o-semiquinone radical anions and cyclopentadienyl radicals were the key free radicals in the generation of coke and tar during the pyrolysis process. And through hydrogenation pyrolysis experiments, it was verified that the relative content of o-semiquinone radical and the solid coke were reduced with a hydrogen supply source. Our results showed that by controlling the key free radicals in the coking process, the formation of coke can be suppressed and the conversion efficiency can be improved.
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高影响因子
MATERIALS LETTERS
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2020
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IF 3.204
Yan Zhao,Minyue Wen,Chunhu He,Changlang Liu,Zongru Li,Yin Liu
The lignin residue produced by straw fermentation or straw acid hydrolysis is used as a carbon source to synthesize graphene. After adding tetrahydrofuran as a modifier and Fe(NO 3 ) 3 as a catalyst to lignin for pretreatment, the resulting product was heat treated at 900℃ for 3 h. The prepared graphene was characterized by XRD, Raman, HRTEM, and the electrochemical properties of the prepared graphene also were tested. The results of this study open up a new way for the efficient preparation of graphene based on renewable resources lignin. The prepared lignin-based graphene was used for electrochemical testing and found to be a good electrode material for super capacitors.
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高影响因子
FUEL
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2020
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IF 5.578
Yuhan Yang,Hongyun Hu,Fu Yang,Hua Tang,Huan Liu,Baojun Yi,Xian Li,Hong Yao
This study, for the first time, investigated the volatiles emission and thermochemical conversion mechanism of bio-waste during pyrolysis in molten salts (NaNO 3 -KNO 3 -NaNO 2 ) at 300 °C. Cations of molten salts acted as catalysts while anions participated in the pyrolysis reaction. Compared with salt-free pyrolysis, more bio-waste was decomposed in molten salts, to produce more than 14 times the mass of gaseous products and twice the mass of liquid products. Furthermore, the thermochemical conversion behavior of typical biomass constituents, i.e. cellulose, hemicellulose and lignin, was also distinguished. The results suggested that lignin was most easily pyrolyzed to form numerous liquid acids, some nitrated aromatic compounds and more CO, H 2 . In contrast, the decomposition of cellulose was certainly restricted while more significant effects of anions were found in hemicellulose cracking by generating nitrogen-containing heterocyclic rings and amines. Besides, interactions among different biomass constituents were confirmed to affect the generation of bio-waste pyrolysis products.
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高影响因子
RENEWABLE ENERGY
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2020
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IF 6.274
Yalun Hu,Mingrui Li,Yunming Fang,Tianwei Tan
Ex-situ catalytic pyrolysis of lignocellulosic biomass is an intriguing technology that combines thermal deconstruction of the feedstock with upgrading of the vapour and liquid intermediates. To date, in contrast with the current fossil fuel-based industrial processes, several fundamental challenges still impede its widespread deployment to generate renewable, cost-competitive biofuels and/or value-added chemicals. Catalyst improvements and process development offer a substantial opportunity to advance the technology. In this work, a novel zeolite catalyst SiC@MZSM-5 was successfully synthesized by growing ZSM-5 on SiC nanowires . The improved thermal conductivity was envisioned to minimize adverse effects of the downstream fixed-bed temperature fluctuation resulting from strong exothermic reactions during catalytic upgrading, hence fostering product distribution regulation. Concurrently, the pyrolysis process was managed to remove the heavy fractions from pyrolysis vapours by its internal recycling and forced secondary degradation, alleviating catalyst deactivation risk and thus extending the regeneration interval. The co-optimization of catalyst and process strategy improved the catalyst lifetime, optimized fixed-bed temperature distribution , and preserved the catalytic performance.
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高影响因子
KEY ENGINEERING MATERIALS
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2012
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IF 0
Si Hui Wang,He Yun Wang,Fan Xing Meng,Ya Li Li
Abstract: The introduction of metal atoms into SiBCN network allows the development of novel high temperature ceramics and functional ceramics. In this work, cerium (Ce) containing polyborosilazane (PBSZ) is synthesized through substitution and polymerization reactions. Ce atoms are incorporated into PBSZ through the lithium replacement of H in PBSZ followed by Ce replacement of lithium. The chemical structure of the PBSZ and as-synthesized Li containing PBSZ are analyzed by Fourier transform infrared (FTIR) shows that the bands at 598 and 1183 cm-1 which can be assigned to Li-N and Si-N-Li stretching. It is suggested that lithium is incorporated into PBSZ. PBSZCe is transformed into SiBCNCe ceramic by pyrolysed in argon. Scanning electron microscope shows that the SiBCNCe ceramics are porous on the surface and corallike in the section. The chemical bondings of SiBCNCe ceramics are BN, the BN, SiC and Si3N4 characterized by X-ray photoelectron spectroscopy.
研究领域:
材料科学
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无机化学
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危险品化学品经营许可证（带存储）