The Experts below are selected from a list of 24456 Experts worldwide ranked by ideXlab platform
Jiaofei Wang - One of the best experts on this subject based on the ideXlab platform.
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building methodology for evaluating the effects of direct Coal liquefaction using Coal Structure chemical index
Fuel, 2021Co-Authors: Zhiqiang Sun, Xing Fan, P N Kuznetsov, Bo Chen, Jiaofei WangAbstract:Abstract As a semi-theoretical and semi-empirical method, Structure-chemical index has classified the utilization of Coals with different Coalification degrees and petrographic constituents in Russia. In this work, the formulas of Structure-chemical index were simplified to building methodology for evaluating the utilization of Coals in direct Coal liquefaction (DCL). Nineteen Coals from Xinjiang, China, were characterized by ultimate analysis and thermal gravimetric analysis, and the corresponding DCL products were evaluated. After the calculation of Structure-chemical index, 12 Coals fall into the liquefaction zone, and exhibit higher H/C ratios and faster pyrolysis rates, which are helpful to Coal liquefaction reaction. Therefore, the conversion rates and oil yields are more than 85.0% and 65.0%, respectively, for Coals in the liquefaction zone, and less than 80.0% and 50.0% for Coals out of the zone.
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In Situ Analysis of Catalytic Effect of Calcium Nitrate on Shenmu Coal Pyrolysis with Pyrolysis Vacuum Ultraviolet Photoionization Mass Spectrometry
Energy & Fuels, 2018Co-Authors: Yang Zhou, Lijun Jin, Jian Zhou, Jiaofei WangAbstract:To investigate the effect of calcium mineral on the product distribution of low-rank Coal pyrolysis, a Chinese subbituminous Coal (Shenmu Coal), and samples with 5% and 10% added calcium content, were selected to study with a homemade pyrolysis vacuum ultraviolet photoionization mass spectrometry (py-VUV-PIMS) system. In this system, secondary reactions of the pyrolysis products were generally inhibited because of in situ sampling, soft ionization, and high vacuum environment, which allowed direct detection of the initial pyrolytic products. Most evolved compounds during temperature-programmed heating from 30 to 650 °C were ionized by a VUV lamp (10.6 eV). The main products include five categories: alkenes, dienes, aromatics, phenols, and dihydroxy aromatics, which were formed via homolytic scission of weak bonds in side chains and bridges between aromatic nuclei in Coal Structure. The calcium mineral additives can dramatically affect pyrolytic product distribution, especially oxygen-containing compounds....
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In Situ Analysis of Catalytic Effect of Calcium Nitrate on Shenmu Coal Pyrolysis with Pyrolysis Vacuum Ultraviolet Photoionization Mass Spectrometry
2018Co-Authors: Yang Zhou, Lijun Jin, Jian Zhou, Jiaofei WangAbstract:To investigate the effect of calcium mineral on the product distribution of low-rank Coal pyrolysis, a Chinese subbituminous Coal (Shenmu Coal), and samples with 5% and 10% added calcium content, were selected to study with a homemade pyrolysis vacuum ultraviolet photoionization mass spectrometry (py-VUV-PIMS) system. In this system, secondary reactions of the pyrolysis products were generally inhibited because of in situ sampling, soft ionization, and high vacuum environment, which allowed direct detection of the initial pyrolytic products. Most evolved compounds during temperature-programmed heating from 30 to 650 °C were ionized by a VUV lamp (10.6 eV). The main products include five categories: alkenes, dienes, aromatics, phenols, and dihydroxy aromatics, which were formed via homolytic scission of weak bonds in side chains and bridges between aromatic nuclei in Coal Structure. The calcium mineral additives can dramatically affect pyrolytic product distribution, especially oxygen-containing compounds. The main reason is that calcium mineral plays a catalytic role in deoxygenation, which prompted incorporation of oxygen-containing compounds into corresponding aromatics, and resulted in the product of BTX levels increase significantly. The decrease in relative average molecular weight indicated the conversion of heavier components into lighter species, in terms of the observed m/z of the evolved gas components
Yang Zhou - One of the best experts on this subject based on the ideXlab platform.
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In Situ Analysis of Catalytic Effect of Calcium Nitrate on Shenmu Coal Pyrolysis with Pyrolysis Vacuum Ultraviolet Photoionization Mass Spectrometry
Energy & Fuels, 2018Co-Authors: Yang Zhou, Lijun Jin, Jian Zhou, Jiaofei WangAbstract:To investigate the effect of calcium mineral on the product distribution of low-rank Coal pyrolysis, a Chinese subbituminous Coal (Shenmu Coal), and samples with 5% and 10% added calcium content, were selected to study with a homemade pyrolysis vacuum ultraviolet photoionization mass spectrometry (py-VUV-PIMS) system. In this system, secondary reactions of the pyrolysis products were generally inhibited because of in situ sampling, soft ionization, and high vacuum environment, which allowed direct detection of the initial pyrolytic products. Most evolved compounds during temperature-programmed heating from 30 to 650 °C were ionized by a VUV lamp (10.6 eV). The main products include five categories: alkenes, dienes, aromatics, phenols, and dihydroxy aromatics, which were formed via homolytic scission of weak bonds in side chains and bridges between aromatic nuclei in Coal Structure. The calcium mineral additives can dramatically affect pyrolytic product distribution, especially oxygen-containing compounds....
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In Situ Analysis of Catalytic Effect of Calcium Nitrate on Shenmu Coal Pyrolysis with Pyrolysis Vacuum Ultraviolet Photoionization Mass Spectrometry
2018Co-Authors: Yang Zhou, Lijun Jin, Jian Zhou, Jiaofei WangAbstract:To investigate the effect of calcium mineral on the product distribution of low-rank Coal pyrolysis, a Chinese subbituminous Coal (Shenmu Coal), and samples with 5% and 10% added calcium content, were selected to study with a homemade pyrolysis vacuum ultraviolet photoionization mass spectrometry (py-VUV-PIMS) system. In this system, secondary reactions of the pyrolysis products were generally inhibited because of in situ sampling, soft ionization, and high vacuum environment, which allowed direct detection of the initial pyrolytic products. Most evolved compounds during temperature-programmed heating from 30 to 650 °C were ionized by a VUV lamp (10.6 eV). The main products include five categories: alkenes, dienes, aromatics, phenols, and dihydroxy aromatics, which were formed via homolytic scission of weak bonds in side chains and bridges between aromatic nuclei in Coal Structure. The calcium mineral additives can dramatically affect pyrolytic product distribution, especially oxygen-containing compounds. The main reason is that calcium mineral plays a catalytic role in deoxygenation, which prompted incorporation of oxygen-containing compounds into corresponding aromatics, and resulted in the product of BTX levels increase significantly. The decrease in relative average molecular weight indicated the conversion of heavier components into lighter species, in terms of the observed m/z of the evolved gas components
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effect of hydrothermal treatment on Structure and liquefaction behavior of baiyinhua Coal
Fuel Processing Technology, 2017Co-Authors: Zhiwei Shi, Lijun Jin, Yang ZhouAbstract:Abstract Baiyinhua (BYH) Coal, a kind of lignite, was hydrothermally treated in an autoclave reactor at 200–350 °C for 30 min and the liquefaction behavior of the treated samples were investigated. To uncouple the complex behavior of the changes in structural characteristics and functional groups of treated samples, the structural change in BYH Coal was investigated by thermogravimetry, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Results reveal that oxygen content and volatile matter in treated sample reduce and carbon content increases. The decrease in atomic ratio of oxygen to carbon and hydrogen to carbon of treated sample indicates the improvement in Coalification degree. CO 2 and CO account for the overwhelming majority of gaseous products from hydrothermal treatment, which can be attributed to the significantly decrease of carboxyl and carbonyl content. The hydrothermal treatment involves the breakup of some weak bonds within Coal Structure, and the main Structure of BYH Coal does not change significantly. A desirable upgraded Coal was obtained by hydrothermal treatment of BYH raw Coal at 250 °C. The liquefaction behavior of Coal can be improved by hydrothermal treatment at 250 °C, and the oil yield increases from 32.9 wt% (dry ash-free basis) of raw Coal to 37.8 wt% (dry ash-free basis). This work illustrates that hydrothermal treatment is a promising approach for upgrading of low rank Coal.
Lijun Jin - One of the best experts on this subject based on the ideXlab platform.
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In Situ Analysis of Catalytic Effect of Calcium Nitrate on Shenmu Coal Pyrolysis with Pyrolysis Vacuum Ultraviolet Photoionization Mass Spectrometry
Energy & Fuels, 2018Co-Authors: Yang Zhou, Lijun Jin, Jian Zhou, Jiaofei WangAbstract:To investigate the effect of calcium mineral on the product distribution of low-rank Coal pyrolysis, a Chinese subbituminous Coal (Shenmu Coal), and samples with 5% and 10% added calcium content, were selected to study with a homemade pyrolysis vacuum ultraviolet photoionization mass spectrometry (py-VUV-PIMS) system. In this system, secondary reactions of the pyrolysis products were generally inhibited because of in situ sampling, soft ionization, and high vacuum environment, which allowed direct detection of the initial pyrolytic products. Most evolved compounds during temperature-programmed heating from 30 to 650 °C were ionized by a VUV lamp (10.6 eV). The main products include five categories: alkenes, dienes, aromatics, phenols, and dihydroxy aromatics, which were formed via homolytic scission of weak bonds in side chains and bridges between aromatic nuclei in Coal Structure. The calcium mineral additives can dramatically affect pyrolytic product distribution, especially oxygen-containing compounds....
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In Situ Analysis of Catalytic Effect of Calcium Nitrate on Shenmu Coal Pyrolysis with Pyrolysis Vacuum Ultraviolet Photoionization Mass Spectrometry
2018Co-Authors: Yang Zhou, Lijun Jin, Jian Zhou, Jiaofei WangAbstract:To investigate the effect of calcium mineral on the product distribution of low-rank Coal pyrolysis, a Chinese subbituminous Coal (Shenmu Coal), and samples with 5% and 10% added calcium content, were selected to study with a homemade pyrolysis vacuum ultraviolet photoionization mass spectrometry (py-VUV-PIMS) system. In this system, secondary reactions of the pyrolysis products were generally inhibited because of in situ sampling, soft ionization, and high vacuum environment, which allowed direct detection of the initial pyrolytic products. Most evolved compounds during temperature-programmed heating from 30 to 650 °C were ionized by a VUV lamp (10.6 eV). The main products include five categories: alkenes, dienes, aromatics, phenols, and dihydroxy aromatics, which were formed via homolytic scission of weak bonds in side chains and bridges between aromatic nuclei in Coal Structure. The calcium mineral additives can dramatically affect pyrolytic product distribution, especially oxygen-containing compounds. The main reason is that calcium mineral plays a catalytic role in deoxygenation, which prompted incorporation of oxygen-containing compounds into corresponding aromatics, and resulted in the product of BTX levels increase significantly. The decrease in relative average molecular weight indicated the conversion of heavier components into lighter species, in terms of the observed m/z of the evolved gas components
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effect of hydrothermal treatment on Structure and liquefaction behavior of baiyinhua Coal
Fuel Processing Technology, 2017Co-Authors: Zhiwei Shi, Lijun Jin, Yang ZhouAbstract:Abstract Baiyinhua (BYH) Coal, a kind of lignite, was hydrothermally treated in an autoclave reactor at 200–350 °C for 30 min and the liquefaction behavior of the treated samples were investigated. To uncouple the complex behavior of the changes in structural characteristics and functional groups of treated samples, the structural change in BYH Coal was investigated by thermogravimetry, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Results reveal that oxygen content and volatile matter in treated sample reduce and carbon content increases. The decrease in atomic ratio of oxygen to carbon and hydrogen to carbon of treated sample indicates the improvement in Coalification degree. CO 2 and CO account for the overwhelming majority of gaseous products from hydrothermal treatment, which can be attributed to the significantly decrease of carboxyl and carbonyl content. The hydrothermal treatment involves the breakup of some weak bonds within Coal Structure, and the main Structure of BYH Coal does not change significantly. A desirable upgraded Coal was obtained by hydrothermal treatment of BYH raw Coal at 250 °C. The liquefaction behavior of Coal can be improved by hydrothermal treatment at 250 °C, and the oil yield increases from 32.9 wt% (dry ash-free basis) of raw Coal to 37.8 wt% (dry ash-free basis). This work illustrates that hydrothermal treatment is a promising approach for upgrading of low rank Coal.
Jonathan P. Mathews - One of the best experts on this subject based on the ideXlab platform.
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mapping internal Structure of Coal by confocal micro raman spectroscopy and scanning microwave microscopy
Fuel, 2014Co-Authors: Alexander Tselev, Jonathan P. Mathews, Ilia N Ivanov, Nickolay V Lavrik, Alex Belianinov, Stephen Jesse, Gareth D Mitchell, Sergei V KalininAbstract:Abstract Structural complexity and variability of the chemical properties define technological applicability of Coal and demand increasing accuracy and spatial resolution from the techniques used for Coal characterization for development of new, clean, and efficient technologies of Coal utilization. Here, we combined spatially-resolved reflectometry, fluorescence, and confocal micro-Raman spectroscopy with high-resolution scanning probe microwave imaging to achieve a nondestructive sub-100-nm spatial resolution mapping of Coal Structure. It was found that this approach allows for high spatial resolution identification of individual elements in Coal architecture, thus potentially generating valuable input for knowledge-driven optimization and design of Coal utilization processes.
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Solvent swelling behavior of Permian-aged South African vitrinite-rich and inertinite-rich Coals
Fuel, 2010Co-Authors: Daniel Van Niekerk, Phillip M. Halleck, Jonathan P. MathewsAbstract:Abstract Two South African Coals similar in rank and age, but different in maceral composition, were studied using solvent swelling. Inertinite-rich Highveld Coal (dominated by semifusinite) and vitrinite-rich Waterberg Coal were evaluated for swelling extent and swelling rate using N-methylpyrrolidone (NMP) and CS 2 /NMP. A stop-motion videography method was developed to study individual particle swelling behavior. This method allowed observation of overshoot and climbing-type swelling, as well as swelling kinetics. Single-particle swelling experiments showed that both Coals exhibited overshoot-type and climbing-type swelling. The inertinite-rich Coal swelled much faster (in both solvents) than the vitrinite-rich Coal. The swelling in CS 2 /NMP was faster for both Coals. Kinetic parameters showed that solvent swelling was governed by relaxation (super-Case II relaxation) of the Coal Structure. X-ray computed tomography was conducted over a 50 h swelling period in NMP for single particles of each Coal. Anisotropic swelling was observed in all the particles (swelling greater perpendicular to the bedding plane than parallel to it). The subtle changes in molecular Structure, fine structural and physical differences resulted in significant differences in solvent swelling behavior.
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methane and carbon dioxide sorption and transport rates in Coal at in situ conditions
Energy Procedia, 2009Co-Authors: Denis J N Pone, Phillip M. Halleck, Jonathan P. MathewsAbstract:Abstract Geologic sequestration of carbon dioxide is an option for the mitigation of industrial emissions. However, considerable effort remains to shift this technology from its current status as potential solution to a safe, effective and trusted foundation to the global energy system. Characterization of gas movement and sorption capacity of Coal at in-situ conditions is required. Using the volumetric method, measurements of CH 4 and CO 2 sorption and diffusion in Coal have been made on powder and non-powder confined Coal. Results obtained, emphasized that the sorption capacity and the kinetics of gas in Coal are both influenced by the stress state of the sample. The application of 6.9 MPa confining stress contributed to about 30% and 80% of sorption capacity reduction for CO 2 and CH 4 respectively. The sorption and diffusion of CO 2 in confined Coal follow two distinct rates described with diffusion coefficients of 2.3×10 −6 m2/s and 9.4×10 −12 m2/s respectively. In contrast, the flow of methane is characterized by a continuous process with a diffusion coefficient of 3.8×10 −7 m 2 /s. These observations confirms the complex interaction of CO 2 with the Coal Structure and stressed that CH 4 and CO 2 sorption and transport in Coal should be characterized differently, specifically when dealing with non-powder confined samples. Consequently, the use of information collected on pulverized Coal samples for the simulation and prediction of long term underground sequestration and enhanced Coalbed methane is not justified.
Alan L Chaffee - One of the best experts on this subject based on the ideXlab platform.
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separation and analysis of maceral concentrates from victorian brown Coal
Fuel, 2019Co-Authors: Yuxin Yan, Marc Marshall, Roy W Jackson, Alan L ChaffeeAbstract:Abstract Four selectively mined lithotypes and a run-of-mine Coal (ROM) have been obtained from the Yallourn Coal seam in the La Trobe Valley, Victoria, Australia and a partial maceral separation of each of them has been carried out using the sink-float method with centrifugal force on a laboratory scale. The yields of liptinite-rich float fractions were between 22.5 and 2.8 wt% in the order of Pale > Light > Med-light ≈ ROM > Dark. Elemental analysis and FTIR showed that the liptinite-rich float fractions had higher H/C ratios and aliphaticities than the corresponding vitrinite-rich sink fractions and this was confirmed by solid state 13C NMR. Pyrolysis-GC-MS using a pyrolysis temperature of 650 °C showed little difference in the distribution of aliphatic peaks but dramatic changes in the relative abundance of triterpenoids between lithotypes and in some cases between float and sink fractions of a lithotype. Variations in yields with pyrolysis temperature suggested that the triterpenoids are loosely bound to the main Coal Structure.
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the effect of densification on brown Coal physical properties and its spontaneous combustion propensity
Fuel, 2017Co-Authors: Mohammad Reza Parsa, Yoshimitsu Tsukasaki, Emily L Perkins, Alan L ChaffeeAbstract:Abstract The process, where brown Coal is extruded after mechanical kneading and then allowed to air dry slowly to form a product known as ‘densified Coal’, was applied to reduce the moisture content of two Victorian brown Coals. NaOH at different concentrations (0–1.5 M) was used as an additive in the kneading step. The spontaneous combustion propensity of the densified products was evaluated and compared against multiple physical properties and morphological features of materials. The densification process reduced the moisture content of the sample from around 60% to around 12%. NaOH addition led to a progressive reduction in the CO 2 surface area, as well as the porosity determined by mercury intrusion, due to the development of a stronger electrostatic network within the Coal Structure. The reduced micropore volume limits the accessibility of O 2 to internal surfaces of the Coal leading to a significant increase in the critical ignition temperature (T cr ) measured by the wire basket test method. SEM imaging indicated that the Coal particle surface changed from spongy and porous for nitrogen dried raw Coal to very smooth and contiguous for densified Coal. These trends also correlated with progressive reduction in the CO 2 surface area, as well as the porosity determined by mercury intrusion porosimetry.