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Li H.-Q.,North University of China | An C.-W.,North University of China | Du M.-Y.,Shanxi Luan Mining Group Ltd. | Wen X.-M.,North University of China | Wang J.-Y.,North University of China
Huozhayao Xuebao/Chinese Journal of Explosives and Propellants | Year: 2016

The thermal decomposition characteristics of DNTF and 2, 4, 6-trinitrotoluene (TNT) were investigated by means of differential scanning calorimetry at different heating rates. The kinetic parameters of thermal decomposition reaction, critical temperature of thermal explosion and thermodynamic parameters were calculated, contrasted and analyzed by Kissinger methed. The results show that the thermal decomposition process of DNTF is different with TNT, it occurs in two stages and the first acts as the major part. The activation energy of DNTF is 168.85kJ/mol, which is about 58kJ/mol higher than that of TNT, revealing that DNTF has a good thermal stability at low temperature. However, all the other thermodynamic parameters of DNTF are higher than those of TNT except the free energy of activation. The decomposition peak temperatures and critical temperature of thermal explosion of DNTF are lower than those of TNT. So, the thermal stability of DNTF is poorer than that of TNT. © 2016, Editorial Board of Journal of Explosives & Propellants. All right reserved. Source


Wang J.-G.,Shanxi Institute of Coal CAS Chemistry | Wang J.-G.,University of Chinese Academy of Sciences | Li D.-B.,Shanxi Institute of Coal CAS Chemistry | Huang W.,Shanxi Luan Mining Group Ltd. | And 2 more authors.
Ranliao Huaxue Xuebao/Journal of Fuel Chemistry and Technology | Year: 2012

Co-based catalyst supported on bi-modal MCM-41 molecular sieves was prepared by incipient-wetness impregnation method; the influence of reduction and oxidation pretreatment on the catalyst structure and its performance in Fischer-Tropsch synthesis (FTS) was investigated. XRD results showed that the cobalt species in the catalyst after the pretreatment is in the form of metal cobalt with face centered cubic crystal phase and the crystallite size is increased from 8.4 nm to 22.6 nm, compared with the untreated one; due to the increase of crystallite size, the Raman characteristic peak shows a blue shift. SEM and TEM results indicated that the cobalt species exhibits good dispersibility. H 2-TPR results indicated that the reduction temperature is reduced and the interaction between metal and support is strengthened after the pretreatment. As a result, the pretreated-catalyst exhibits lower FTS activity and higher selectivity to methane than the fresh catalyst; however, the selectivity to C 5~18 products over the pretreated-catalyst is improved obviously, especially, the selectivity to C 5~11, which is about twice as that over the untreated one. Source


Kong X.,Shanxi Institute of Coal CAS Chemistry | Kong X.,University of Chinese Academy of Sciences | Hou B.,Shanxi Institute of Coal CAS Chemistry | Jia L.-T.,Shanxi Institute of Coal CAS Chemistry | And 4 more authors.
Ranliao Huaxue Xuebao/Journal of Fuel Chemistry and Technology | Year: 2013

Two Al2O3-modified catalysts were prepared by urea hydrolysis method and precipitation disposition method respectively. Combined with N2 adsorption, XRD, XPS and H2-TPR, the effects of Al2O3 on the physico-chemical properties and catalytic properties for the Fischer-Tropsch synthesis were investigated. It was found that the metal-support interaction could be effectively strengthened for both catalysts. Consequently, the dispersion of the catalyst was enhanced and the Fischer-Tropsch synthesis activity was increased. The results also indicated that the modification of Co/SiC catalyst strongly depended on the preparation method. The highest CO conversion was observed on the catalyst prepared by urea hydrolysis method due to the superior dispersion and good reducibility. Besides, the catalytic stability was enhanced due to the stronger interaction between cobalt and Al2O3 prepared by precipitation disposition method. Source


Wang J.,Shanxi Institute of Coal CAS Chemistry | Wang J.,University of Chinese Academy of Sciences | Li D.,Shanxi Institute of Coal CAS Chemistry | Hou B.,Shanxi Institute of Coal CAS Chemistry | And 8 more authors.
Cuihua Xuebao/Chinese Journal of Catalysis | Year: 2011

A series of cobalt-based catalyst samples supported on double mesoporous MCM-41 for Fischer-Tropsch synthesis (FTS) were prepared using three methods, incipient-wetness impregnation (IWI), vapor-induced hydrolysis (VIH), and excessive impregnation (EI). The catalyst samples were characterized by N2 physisorption, X-ray diffraction (XRD), temperature-programmed reduction (H2-TPR) and Raman spectroscopy. The N2 physisorption results showed that the samples prepared by IWI and VIH retained the double mesoporous character, and the cobalt particles were mainly located in the pore. The FTS results showed that the reducibility and dispersion of active species of the samples prepared by IWI and EI were very high. The catalyst prepared by IWI had the smallest Co3O4 crystallite size and the highest dispersion and showed higher FTS activity, lower CH4 selectivity and higher C5+ selectivity. Source


Tian L.,Henan Polytechnic University | Cao Y.,Henan Polytechnic University | Chai X.,Shanxi Luan Mining Group Ltd. | Liu T.,Shanxi Luan Mining Group Ltd. | And 6 more authors.
Fuel | Year: 2015

Abstract Permeability and pressure are two important parameters for characterizing coal reservoirs and for evaluating coalbed methane (CBM) production potential. In this study, the reservoir pressure and permeability of six steel-cased CBM wells at Yuwu Coal Mine (Luan coal mining area, Qinshui Basin, China) were studied using new injection falloff testing (IFOT) methodology. The tested reservoir represents coal #3 of the lower Permian Shanxi Formation, the main target coal seam for coalbed methane exploration and production in Qinshui Basin. The results show that on average coal #3 has an ultra-low permeability (0.001-0.043 mD) and a low pressure gradient (4.0 kPa/m). These values are significantly lower than those of previously collected data from open holes in adjacent wells. However, the validity of the new results was confirmed using two additional lines of evidence: (1) analysis of 10 CBM production wells adjacent the current test area and; (2) data from a long-term monitoring well in an Ordovician limestone aquifer, located below coal #3. On the basis of the results, it can be concluded that (1) using the IFOT method in cased wells, in which shut-in times were extended by 7-11 times that of the injection time, provides reliable data on reservoir parameters (including pressure and permeability); (2) coal #3 is characterized by very low permeability and very low pressure; (3) the low reservoir pressure is related to the Xinan Spring Group, located on the eastern edge of the Qinshui Basin, which discharges reservoir groundwater to the surface hydrological system; and (4) low permeability may be caused by low reservoir pressure and by a cleat system filled with post-structural mineralization. These conclusions were used to further optimize stimulation design and production management for this CBM play. As a result, there has been a good production rate for these wells since 2011. © 2015 Elsevier Ltd. Source

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