COMBUSTION AND FLAME
·
2018
·
IF 4.494
Qiang Lu,Bin Hu,Zhen-xi Zhang,Yu-ting Wu,Min-shu Cui,Ding-jia Liu,Chang-qing Dong,Yong-ping Yang
Understanding the fundamental reactions and mechanisms during biomass fast pyrolysis is essential for the development of efficient pyrolysis techniques. In this work, quantum chemistry calculation, kinetic analysis and fast pyrolysis experiment were combined to reveal the cellulose pyrolysis mechanism . During cellulose pyrolysis, the indigenous interior units, reducing end (RE end) and non-reducing end (NR end) initially form various characteristic chain ends and dehydrated units which then evolve into different pyrolytic products. As the rising of the degree of polymerization (DP), reactions occurring at the interior unit and NR end are more competitive than those taking place at the RE end, resulting in distinct pyrolytic product distribution for cellulose and glucose-based carbohydrates. The reactions occurring at the three indigenous units of cellulose chain all favor the formation of levoglucosan-terminated end (LG end) and/or NR end, which then generate levoglucosan (LG). The acyclic d -glucose end (AG end), which mainly derives from the RE end, is essential for the formation of 1,6-anhydro-β- d -glucofuranose (AGF), 1,4:3,6-dianhydro-α- d -glucopyranose (DGP), furfural (FF), 5-hydroxymethyl furfural (5-HMF) and hydroxyacetaldehyde (HAA). Compared with the chain ends, the dehydrated units are not feasible to be generated, and their decomposition favors the formation of HAA.
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
·
2023
·
IF 6
Jia Liu,Shanjian Liu,An Zhao,Dongmei Bi,Di Yao,Ranran Kong
Considering the depletion of fossil fuels and the cumbersome traditional synthesis process of chemical compounds containing nitrogen, there is increased interest in direct production of nitrogenous compounds (bio-oil) from nitrogen-rich pyrolysis of biomass. In this study, a new strategy for the preparation of both nitrogen-rich bio-oil and biochar by co-pyrolysis of chitin and nitrogen carriers was proposed. Four different nitrogen carriers (urea, ammonium acetate , glutamate, and polyurethane) were selected and the thermal behavior of the mixtures as well as the synergistic competitive effects between the pyrolytic volatiles were characterized. Simultaneously, the properties of the co-pyrolysis products and the distribution of the main components in bio-oil were analyzed. The results showed that co-pyrolysis of chitin and nitrogen carriers had a synergistic effect. Glutamate had the most significant inhibitory effect on volatile gases, while only polyurethane promoted the release of volatile gases. Compared to the pyrolysis of chitin alone, the addition of urea, ammonium acetate and polyurethane effectively reduced the activation energy of the reaction. The addition of nitrogen carriers promoted the production of amines. Co-pyrolysis of urea and glutamate (40%) increased the content of nitrogenous compounds by 14.84% and 3.41%, respectively. However, the addition of ammonium acetate and polyurethane hindered the conversion of oxygenated compounds to nitrogen-containing compounds. In addition, the formation pathways of chitin pyrolysis and co-pyrolysis products were summarized. This work expanded the boundaries of high-value utilization of chitin.
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
·
2023
·
IF 6
Qingqi Zheng,Zhiyu Li,Tianyang Guo,Qingwen Fan,Song Hu,Jun Xiang,Peng Fu
To gain new insights into lignin pyrolysis, the synergistic development of carbon skeleton and pore networks in a wide temperature range of 200–800 °C was unraveled. The relative abundance of aromatic carbon structures increased exponentially with increasing temperature, as determined by 13 C NMR deconvolution. Additionally, the g-factor type of radicals changed from O-centered (g-factor <2.0030) to C-centered (g-factor >2.0040) radicals. The evolution of the char macromolecules structure from disorder to order was principally characterized by a decrease in aromatic spacing ( d 002 , 3.36→3.37 Å) an d an increase in stacking degree ( L c , 7.89→8.67 Å) and aromaticity ( f a , 75.19%→96.94%). f a h a s a strong negative linear correlation with d 002 ( R 2 = 0.965). Ternary quadratic polynomials can relate specific surface area, total pore volume, and relative carbon content to the pore fractal dimension. The hypothesized chemical reaction networks and synergistic development of carbon skeleton and pore networks are essential for lignin effective valorization by a pyrolysis-based biorefinery strategies.
✓ 已验证
产品关联
DOI
高影响因子
PROCEEDINGS OF THE COMBUSTION INSTITUTE
·
2022
·
IF 6.535
Shashank S. Nagaraja,Jinhu Liang,Bingzhi Liu,Qiang Xu,Can Shao,Goutham Kukkadapu,Haitao Lu,Zhandong Wang,Willam J. Pitz,S. Mani Sarathy,Henry J. Curran
Iso -olefins, in the C 5 –C 8 range can potentially be blended with renewable gasoline fuels to increase their research octane number (RON) and octane sensitivity (S). RON and S increase with the degree of branching in iso -olefins and this is a desirable fuel anti-knock quality in modern spark-ignited direct-injection engines. However, these iso -olefins tend to form larger concentrations of aromatic species leading to the formation of polycyclic aromatic hydrocarbons (PAHs). Thus, it is important to understand the pyrolysis chemistry of these iso -olefins. In this study, a new detailed chemical kinetic mechanism is developed to describe the pyrolysis of tetramethyl ethylene (TME), a symmetric iso -olefin. The mechanism, which includes the formation of PAHs, is validated against species versus temperature (700–1160 K) measurements in a jet-stirred reactor at atmospheric pressure and in a single-pulse shock tube at a pressure of 5 bar in the temperature range 1150–1600 K. Synchrotron vacuum ultraviolet photoionization mass spectrometer (SVUV-PIMS) and gas chromatography (GC) systems were used to quantify the species in the jet-stirred reactor and in the single-pulse shock tube, respectively. The mechanism derives its base and PAH chemistry from the LLNL PAH sub-mechanism. The predictions are accurate for most of the species measured in both facilities. However, there is scope for mechanism improvement by understanding the consumption pathways for some of the intermediate species such as isoprene. The formation of 1, 2, and 3-ring aromatic species such as benzene, toluene, naphthalene and phenanthrene measured experimentally is analyzed using the chemical kinetic mechanism. It is found that the PAH formation chemistry for TME under pyrolysis conditions is driven by both propargyl addition reactions and the HACA mechanism.
✓ 已验证
产品关联
DOI
高影响因子
ChemistrySelect
·
2022
·Vol. 7
·期 39
·e202202129
·
IF 2.307
Ting Yu,Zhenghua Qian,Lin Li,Zonghui Lu,Bin Li,Qiang Zhang,Xiaofeng Liu,Hui He,Yanbo Qiao,Guoan Ye
Graphical This is a new method of producing nuclear material. ThO 2 NPs are synthesized by pyrolysis of an undiscovered thorium-based MOF. The MOF-derived ThO 2 NPs can easily be sintered to form ThO 2 ceramics. (Twitter: @yuting0437) A new method is demonstrated for synthesizing thorium dioxide (ThO 2 ) nanoparticles (NPs) by thermal decomposition of an undiscovered thorium-based metal-organic framework (MOF). Upon heating at 520 °C, the thorium-based MOF crystals, designated Th-MTB, are converted completely to ThO 2 NPs with an average size of 150 nm. The MOF-derived ThO 2 NPs are easily sintered to form ThO 2 ceramics which have good thermal conductivity. The crystalline grains of ThO 2 grow continuously during sintering.The method for the synthesis of ThO 2 NPs could have potential applications in the production of nuclear materials.
✓ 已验证
DOI
高影响因子
JOURNAL OF ENVIRONMENTAL MANAGEMENT
·
2022
·
IF 8.91
Xuan Guo,Huili Zhang,Yunming Fang
Ambient pressure hydro-deoxygenation (HDO) of the phenolic-rich pyrolysis liquid fraction is a complex task due to the presence multiple phenolic compounds and light oxygenates. The phenolic-rich fraction differs from the overall pyrolysis liquid, known to be prone to re-polymerization and coking in the reactor or of the catalyst. In the present research, hydro-deoxygenation of oxygen-containing compounds in the phenolic fraction over Mo-based catalysts was carried out for the first time. It was found that Mo-based catalysts can successfully upgrade the phenolics into aromatics, the conversion rate was nearly 100%. The small amount of light oxygenates in the phenolic-rich fraction had no obvious effect on the hydro-deoxygenation reaction, the phenolic conversion was more than 95%. After assessing the performance for a representative phenolic model compound, the reaction was also successfully carried out on the phenolic fraction of the real pyrolysis liquid. It can be concluded that the catalysts can also be used for the HDO of the real pyrolysis liquid fraction at atmospheric pressure.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
FUEL
·
2022
·
IF 8.035
Bin Hu,An-shuai Cheng,Wen-luan Xie,Ji Liu,Yao-bing Huang,Ling-jun Zhu,Bing Zhang,Ming-xiao Li,Li Zhao,Ti-peng Wang,Qiang Lu
Pyrolysis is a promising thermal conversion technique of biomass to tackle the energy crisis and environmental pollution. Furfural (FF) is an important pyrolysis product from biomass-based materials and a crucial platform compound for energy and fuels. In the present study, we developed a new and green approach to selectively produce FF through the oxalic acid-assisted fast pyrolysis (OAFP) of corncob (CC). The FF yield was up to 16.5 wt% (based on raw CC) through the fast pyrolysis of the solid mixture of CC and OA with a ratio of 1:4 (CC/OA) at 400 °C during the micro-pyrolysis coupled with online-detection experiments. The corresponding FF selectivity was 56.5% (based on raw CC). Under similar experimental parameters, a yield of 10.0 wt% (based on raw CC) was achieved with a lab-scale setup. Experiment and density functional theory (DFT) calculation results suggested that OA played a catalyst-like role in the selective formation of FF from hemicellulose (mainly xylose units) of CC and meanwhile decomposed during the pyrolysis process. The formic acid (FA) decomposed from OA had a similar but lighter effect than OA. With the assistance of OA, the energy barriers of the FF formation reactions decrease dramatically and the competitiveness of the pathways is also altered, which contributes a lot to the FF selective generation. FF is mainly generated in a chain propagation pattern from the acyclic reducing end and unsaturated (C4 C5 bond) non-reducing end of the xylan chain.
✓ 已验证
产品关联
DOI
高影响因子
Biofuels Bioproducts & Biorefining-Biofpr
·
2022
·Vol. 17
·期 2
·355-362
·
IF 5.239
Yanqian Gu,Shasha Liu,Gang Wu,Yinlong Wu,Shoujun Zhang,Yong Huang,Shu Zhang,Hong Zhang
Biomass is the sole carbon-containing renewable resource on Earth, and has high potential for the production of platform chemicals. Phenol, one of the most important platform chemicals, is generally derived from lignin conversion. In this study, the production of phenol from co-pyrolysis of cellulose and sodium borohydride at different mass ratios is investigated in detail. The results show that even a small amount of sodium borohydride (cellulose–sodium borohydride = 10:1) could effectively promote the conversion of cellulose to phenol through cellulose-derived levoglucosan intermediates. As the mass ratio of cellulose–sodium borohydride decreased, the relative content of phenol in the products significantly increased, and could be as high as 11.0% when the ratio of cellulose to sodium borohydride was 2:1. Glycosidic bonds in cellulose were considered to play an important role in its catalytic conversion. Furthermore, the resulting solid product could be used as a B-doping carbon material, which is desirable in various research fields. This study provided a novel method for the highly efficient utilization of cellulose. © 2022 Society of Chemical Industry and John Wiley & Sons, Ltd.
✓ 已验证
产品关联
DOI
高影响因子
ENERGY
·
2022
·
IF 8.857
Yi Wei,Licong Lu,Xudong Zhang,Jianbing Ji
Cellulose was used as feedstock to investigate the effect of electrolysis on the molten salt pyrolysis process . The mechanism of cellulose transformation in the electrochemically assisted molten carbonate pyrolysis (EMCP) system was evaluated by comparison with the molten carbonate pyrolysis (MCP) system. The gas product yield from the EMCP system reached 70.5 wt%, at the expense of the liquid product and tar. The maximum H 2 yields up to 8.31 mol/kg of cellulose at low temperatures without the catalyst in the EMCP system. Cellulose decomposition was catalyzed by the molten salt to produce a large number of volatiles, where the aldehyde groups in the volatiles were electrochemically oxidized to carboxyl groups. Subsequently, the carboxyl compounds combined with alkali metal cations to release hydrogen radicals and then underwent secondary cracking, along with the volatiles having low chemical bond energies. The EMCP system follows the Shrink Cylinder model, which is dominated by the two-dimensional reaction on the surface of the graphite electrode , where the electrolysis process is the determining step.
✓ 已验证
产品关联
DOI
高影响因子
COMBUSTION AND FLAME
·
2022
·
IF 5.767
Junrui Duan,Haowei Hu,Jie Ji
In this study, arabinose was selected as the model compound of hemicellulose . The pyrolysis experiments were conducted by combined thermogravimetry-Fourier infrared spectroscopy-gas chromatography-mass spectrometry (TG-FTIR-GC–MS) technique. The evolution of functional groups was observed. Experimental results indicated that the main gas products were H 2 O, CO 2 , and CH 4 . And volatiles also contained many furan derivatives, sugar derivatives, aromatic hydrocarbon derivatives, and other trace products. In addition, the quantum chemistry calculations were utilized to reveal the formation mechanisms and pathways of the significant products from arabinose pyrolysis. Initially, arabinose prefers to undergo a ring-opening reaction to form acyclic D-arabinose with the activation energy of 177.6 kJ/mol, which is the primary source of each product. Furfural (PD) is the most abundant furan derivative. The ring-condensation reaction first of arabinose and the isomerization reaction first of D-arabinose are the favorable paths to form it in terms of energy. The C1-C2 bond scission of D-arabinose is more favorable to form furan (PA) and formic acid . The dehydration mechanism first of arabinose is the dominant path to generate 2,7-dioxabicyclo[2.2.1]heptan-5-one (PE). The formation of acetic acid (PB) is kinetically and thermodynamically favorable. Once it is formed, it is easy to decompose into CO 2 and CH 4 . The formation of 2(5H)-furanone (PC) is restricted by the decarboxylation reaction of D-arabinose, which has a high energy barrier of 384.8 kJ/mol. To conclude, a deep understanding of the pyrolysis mechanism of arabinose could be obtained through the combination of experiments and quantum chemistry calculations.
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
·
2022
·
IF 6.437
Shiyun Tang,Qiuyuan Xu,Kexin Liu,Junjiang Guo,Anjiang Tang
Coking with carbon deposition in hydrocarbon fuel (C x H y ) pyrolysis at high temperature is a serious problem to be considered. In this work, single component C x H y with different structures was used as the probe of the carbon deposition. Thirteen simple and representative of alkanes, cycloalkanes , aromatics and O-containing C x H y were selected as the model compounds to decompose and coking in microchannel continuous flow reactor under the same conditions. The distributions of gas, liquid and solid phase products formed by C x H y pyrolysis were characterized by GC, GC-MS, SEM and TPO-IR respectively. The results demonstrate that the molecular structure of C x H y has a great influence on pyrolysis and coking behavior. For all alkanes, CH 4 , C 2 H 4 , C 3 H 6 and C 4 H 8 are the most abundant in gaseous products, and their total content exceeds 70 %. For cycloalkanes, monocyclic cyclohexane pyrolysis tends to produce C 2 H 4 , C 4 H 8 and 1,3-C 4 H 6 , while bicyclic decahydronaphthalene pyrolysis tends to produce CH 4 , C 2 H 4 and C 3 H 6 . For aromatics, CH 4 and C 2 H 4 are the main products in the pyrolysis gas phase of benzene, toluene and ethylbenzene . Interestingly, in the liquid phase of the pyrolysis of O-containing C x H y (ethanol, acetone and tetrahydrofuran), most of the products are oxygenated compounds and no aromatics. SEM and TPO-IR revealed that at least three carbon species were formed by cracking of C x H y molecules with different structures, including amorphous, filamentous and granular carbon. However, due to the great and complex influence of C x H y molecular structure on the micro morphology of carbon deposition, it is difficult to classify all carbon species at present, which needs further experiments and researches.
✓ 已验证
产品关联
DOI
高影响因子
INORGANIC CHEMISTRY
·
2021
·
IF 5.165
Dehui Leng,Tingting Wang,YingFen Li,Zibin Huang,Huimin Wang,Yixin Wan,Xiaoxiao Pei,Junli Wang
Plasmonics, especially the localized surface plasmon resonance (LSPR) in non-noble metal bismuth nanoparticles (Bi NPs), and its spectral features and applications have stimulated increasing research interest in recent years. However, the lack of mature methods to prepare Bi NPs with a well-controlled size and/or shape significantly limits the experimental investigations concerning the LSPR optical properties. Herein, we realize the size-tunable synthesis of nearly monodisperse spherical Bi NPs through a thiolate pyrolysis reaction in solution. The instantaneous thermolysis of a layered molecular intermediate, bismuth dodecanethiolate [Bi(SC12H25)3], results in a classical LaMer mechanism for the nucleation and growth of Bi NPs, allowing for a precise size control from 65 to 205 nm in the average diameter. The diameter tunability enables a systematic study on the size dependence of LSPR optical properties of Bi NPs, and we observe rich ultraviolet–visible–near-infrared spectral responses arising from the LSPR absorption and scattering of Bi NPs as their size varies, which will greatly benefit the light harvesting and manipulation in the solar spectrum. Furthermore, we find that a complete oxidation occurs to Bi NPs under air flow at the temperature when they melt and accordingly generate metastable tetragonal-phase β-Bi2O3 NPs that show an optical band gap of 2.15 eV and interesting temperature-dependent β → α → δ → (γ + β) polymorphic transitions.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）