The oxidative desulfurization of a real refinery feedstock (i.e.,non-hydrotreated kerosene with total sulfur mass content of 0.16%) with a mixture of hydrogen peroxide and acetic acid was studied.The influences of var...The oxidative desulfurization of a real refinery feedstock (i.e.,non-hydrotreated kerosene with total sulfur mass content of 0.16%) with a mixture of hydrogen peroxide and acetic acid was studied.The influences of various operating parameters including reaction temperature (T),acid to sulfur molar ratio (nacid/nS),and oxidant to sulfur molar ratio (nO/nS) on the sulfur removal of kerosene were investigated.The results revealed that an increase in the reaction temperature (T) and nacid/nS enhances the sulfur removal.Moreover,there is an optimum nO/nS related to the reaction temperature and the best sulfur removal could be obtained at nO/nS=8 and 23 for the reaction temperatures of 25 and 60°C,respectively.The maximum observed sulfur removal in the present oxidative desulfurization system was 83.3%.展开更多
Evaporating bubble column reactor (EBCR) is a kind of aerated reactor in which the reaction heat is removed by the evaporation of volatile reaction mixture. In this paper, a mathematical model that accounts for the ga...Evaporating bubble column reactor (EBCR) is a kind of aerated reactor in which the reaction heat is removed by the evaporation of volatile reaction mixture. In this paper, a mathematical model that accounts for the gas-liquid exothermic reaction and axial dispersions of both gas and liquid phase is employed to study the performance of EBCR for the process of p-xylene(PX) oxidation. The computational results show that there are remarkable concentration and temperature gradients in EBCR for high ratio of height to diameter (H/DT). The temperature is lower at the bottom of column and higher at the top, due to rapid evaporation induced by the feed gas near the bottom. The concentration profiles in the gas phase are more nonuniform than those (except PX) in the liquid phase, which causes more solvent burning consumption at high H/DT ratio. For p-xylene oxidation, theo ptimal H/DT is around 5.展开更多
Coal and coal-shale both tend to undergo spontaneous combustion under favourable atmospheric conditions. The Wits-Ehac index has been developed in South Africa since the late 1980's to test the spontaneous combust...Coal and coal-shale both tend to undergo spontaneous combustion under favourable atmospheric conditions. The Wits-Ehac index has been developed in South Africa since the late 1980's to test the spontaneous combustion liability of coal. However, in some cases, the Wits-Ehac index fails to produce tangible results when testing coal-shales. To overcome this problem, a new apparatus has been developed to test carbonaceous materials such as coal and coal-shale under chemical reactions with oxygen and an index has been obtained. This index is called the Wits-CT index. The equipment emulates the influence of oxygen adsorption on carbonaceous material for a period of 24 h without a heating system.The Wits-CT index uses the total carbon content of the sample and the temperature variations obtained from the samples during reaction with oxygen to predict the spontaneous combustion liability. Eighteen samples have been analyzed using both indices and the results are in-line. It was found that coals and coal-shales with higher values of the Wits-CT index are more liable to spontaneous combustion.Further research on different coal-shales is underway in order to establish an extensive database for coal and coal-shales, together with known incidences of self-heating.展开更多
Oxidation of coke deposited on spent catalytic cracking catalysts was compared with that of coal and coal char via the non-isothermal oxidation means, i.e. the thermal-gravimetric analysis （TGA） and the differential...Oxidation of coke deposited on spent catalytic cracking catalysts was compared with that of coal and coal char via the non-isothermal oxidation means, i.e. the thermal-gravimetric analysis （TGA） and the differential thermal analysis （DTA）. Oxidation kinetic parameters were further investigated by model-fitting methods. The test results showed that the oxidation of spent catalysts was a quite mild process, while coal and coal char experienced sharp weight loss during oxidation. The temperature for commencement and termination of oxidation increased in the following order： coal〈coal char〈spent catalysts, and the oxidation of the three tested materials displayed a self-catalytic nature, with their largest oxidation rate appearing at a weight percent of 24.96%, 34.21% and 57.93%, respectively. The oxidation of spent catalysts obeyed a random nucleation model for the first-order reaction, with Ea=206.13 kJ/mol and lgA=10.10, and the oxidation of coal could be a diffusion-controlled reaction mechanism, with Ea=161.61 kJ/mol and lgA=7.74, while the oxidation of coal char also obeyed a random nucleation model for the first-order reaction, with Ea= 149.36 k J/mol and lgA=7.89.展开更多
The pretreatment of low rank coal with nitric acid oxidation can promote its bio-liquefaction. However, the detailed mechanism of which remains an unresolved problem. In the present work, the characteristics of Fushun...The pretreatment of low rank coal with nitric acid oxidation can promote its bio-liquefaction. However, the detailed mechanism of which remains an unresolved problem. In the present work, the characteristics of Fushun coal before and after oxidation by nitric acid were investigated combined with elemental composition, pore volume and pore size, Zeta potential, FT-IR, and 13C solid NMR spectrum analysis. The results show that the inorganic substance inlaid in coal are dissolved by ni- tric acid, which results in the decrease of coal ash content and increase of pore volume and pore size. Furthermore, there exist obvious chemical reactions between nitric acid and the functional groups of coal including aromatic ring carboxylation, side chain alkyl of aromatic ring oxidation and aromatic ring nitration. Among these reactions, some led to the increase in content of carboxyl, aliphatic carbon connected with O and humic acid carbon, while others caused the reduction of aromaticity, methyl carbon, substituted aryl carbon and side chain.展开更多
Gas products from the process of coal oxidization and spontaneous combustion have been studied at different temperatures with FTI spectroscopic tests. With temperatures rising to about 30~100 ℃, water and carbon diox...Gas products from the process of coal oxidization and spontaneous combustion have been studied at different temperatures with FTI spectroscopic tests. With temperatures rising to about 30~100 ℃, water and carbon dioxide gas were formed and from about 105~150 ℃, carbon monoxide was produced. Using the DFT B3LYP method with a 6-311G basis set, the reaction system, where spontaneous combustion between coal and oxygen occurs and produces water and monoxide, has been studied, with the geometric configuration for all stagnation points on the potential reaction energy surface optimized. With a frequency analysis and an IRC method, transient formations were tested. Our results indicate that in the reaction of coal oxidization and spontaneous com-bustion producing carbon dioxide and water, oxygen molecules attack carbon atoms of the terminal of the propyl alcohol group on the lateral chain of benzene rings, which causes this propyl alcohol group to produce the acid (-CH2-CH2-COOH) group and water. This acid group continues its break up into carbon dioxide and the (-CH2-CH3) ethyl group. We have come to the conclusion that this water-and-carbon dioxide-production reaction is spontaneous, based on the observation of the energy released by the reaction.展开更多
This research presents the results of system validation tests for an SOFC power system. In the study, the system was heated up without electric device, i.e., the fuel providing the required thermal energy through an i...This research presents the results of system validation tests for an SOFC power system. In the study, the system was heated up without electric device, i.e., the fuel providing the required thermal energy through an integrated BOP （balance of plant）. The ex-situ experiments, without an SOFC stack installed in the system, were fast conducted to investigate the operability of a BOP apparatus. It was found that the BOP possessed high conversion rates for both steam reforming and water gas shift reactions. The total fuel concentration of hydrogen and carbon monoxide from the reformer was around 91.2%. The system validation tests showed that, with the natural gas as fuel, the output power from the stack reached to 1,060 W, while the fuel utilization efficiency and electrical efficiency were 67.16% and 45.0%, respectively. A steady 600-hour system operation test was carried out at an average system temperature of 694℃. Of which, a 36-cell stack was employed for the test. Meanwhile, the current, voltage and output power were 26 A, 32.3 V and 840 W, respectively, and its electrical efficiency was around 33.4%.展开更多
Coal gangue was calcinated under air, nitrogen, carbon dioxide, air-hydrogen, and hydrogen atmospheres. The effects of different calcination temperatures and atmospheres on the mineral composition of activated coal ga...Coal gangue was calcinated under air, nitrogen, carbon dioxide, air-hydrogen, and hydrogen atmospheres. The effects of different calcination temperatures and atmospheres on the mineral composition of activated coal gangue were investigated by X-ray diffraction. Moreover, the acid leaching kinetics of aluminum oxide from coal gangue was investigated with sulfuric acid. It showed that the air atmosphere promoted kaolinite decomposition during coal gangue calcination. The hydrogen atmosphere promoted the activation and decomposition of kaolinite at reaction temperatures exceeding 650℃. The carbon dioxide atmosphere eliminated the influence of residual carbon on coal gangue. When the ratio of acid/coal gangue was 1.5 and reaction temperature was 650℃, the sulfuric acid leaching rate under air, air-hydrogen, carbon dioxide, hydrogen and nitrogen atmospheres were 93.66%, 90.90%, 84.06%, 81.91% and 77.54% respectively. The acid leaching reaction process conformed to unreacted shrinking core model of particle unchanged, and was controlled by the interracial chemical reaction. The reaction kinetic equation for the leaching process was 1-（1-x）1/3=kt with an apparent activation energy of 48.97 kJ/mol.展开更多
基金Supported by the R&D center of Esfahan refinery (Esfahan,Iran)the technical supports of central laboratory of Esfahan Refinery for total sulfur analysis
文摘The oxidative desulfurization of a real refinery feedstock (i.e.,non-hydrotreated kerosene with total sulfur mass content of 0.16%) with a mixture of hydrogen peroxide and acetic acid was studied.The influences of various operating parameters including reaction temperature (T),acid to sulfur molar ratio (nacid/nS),and oxidant to sulfur molar ratio (nO/nS) on the sulfur removal of kerosene were investigated.The results revealed that an increase in the reaction temperature (T) and nacid/nS enhances the sulfur removal.Moreover,there is an optimum nO/nS related to the reaction temperature and the best sulfur removal could be obtained at nO/nS=8 and 23 for the reaction temperatures of 25 and 60°C,respectively.The maximum observed sulfur removal in the present oxidative desulfurization system was 83.3%.
基金Supported by the National Natural Science Foundation of China (No. 20076039) and SINOPEC.
文摘Evaporating bubble column reactor (EBCR) is a kind of aerated reactor in which the reaction heat is removed by the evaporation of volatile reaction mixture. In this paper, a mathematical model that accounts for the gas-liquid exothermic reaction and axial dispersions of both gas and liquid phase is employed to study the performance of EBCR for the process of p-xylene(PX) oxidation. The computational results show that there are remarkable concentration and temperature gradients in EBCR for high ratio of height to diameter (H/DT). The temperature is lower at the bottom of column and higher at the top, due to rapid evaporation induced by the feed gas near the bottom. The concentration profiles in the gas phase are more nonuniform than those (except PX) in the liquid phase, which causes more solvent burning consumption at high H/DT ratio. For p-xylene oxidation, theo ptimal H/DT is around 5.
基金conducted in the context of coal-shale spontaneous combustion in the eMalahleni coalfields, South Africa was financially sponsored by Coaltech
文摘Coal and coal-shale both tend to undergo spontaneous combustion under favourable atmospheric conditions. The Wits-Ehac index has been developed in South Africa since the late 1980's to test the spontaneous combustion liability of coal. However, in some cases, the Wits-Ehac index fails to produce tangible results when testing coal-shales. To overcome this problem, a new apparatus has been developed to test carbonaceous materials such as coal and coal-shale under chemical reactions with oxygen and an index has been obtained. This index is called the Wits-CT index. The equipment emulates the influence of oxygen adsorption on carbonaceous material for a period of 24 h without a heating system.The Wits-CT index uses the total carbon content of the sample and the temperature variations obtained from the samples during reaction with oxygen to predict the spontaneous combustion liability. Eighteen samples have been analyzed using both indices and the results are in-line. It was found that coals and coal-shales with higher values of the Wits-CT index are more liable to spontaneous combustion.Further research on different coal-shales is underway in order to establish an extensive database for coal and coal-shales, together with known incidences of self-heating.
文摘Oxidation of coke deposited on spent catalytic cracking catalysts was compared with that of coal and coal char via the non-isothermal oxidation means, i.e. the thermal-gravimetric analysis （TGA） and the differential thermal analysis （DTA）. Oxidation kinetic parameters were further investigated by model-fitting methods. The test results showed that the oxidation of spent catalysts was a quite mild process, while coal and coal char experienced sharp weight loss during oxidation. The temperature for commencement and termination of oxidation increased in the following order： coal〈coal char〈spent catalysts, and the oxidation of the three tested materials displayed a self-catalytic nature, with their largest oxidation rate appearing at a weight percent of 24.96%, 34.21% and 57.93%, respectively. The oxidation of spent catalysts obeyed a random nucleation model for the first-order reaction, with Ea=206.13 kJ/mol and lgA=10.10, and the oxidation of coal could be a diffusion-controlled reaction mechanism, with Ea=161.61 kJ/mol and lgA=7.74, while the oxidation of coal char also obeyed a random nucleation model for the first-order reaction, with Ea= 149.36 k J/mol and lgA=7.89.
基金Supported by the National Natural Science Foundation of China （50874107） the Guizhou Science and Technology Fund （Qiankehe J zi [2012]2306）+1 种基金 the Guizhou High-level Talent Special Assistant Fund （TZJF-2011-04） the Guizhou Research Laboratory Platform of Clean and Efficient Use of Coal Resources （Qianke Platform [2011] 4003）
文摘The pretreatment of low rank coal with nitric acid oxidation can promote its bio-liquefaction. However, the detailed mechanism of which remains an unresolved problem. In the present work, the characteristics of Fushun coal before and after oxidation by nitric acid were investigated combined with elemental composition, pore volume and pore size, Zeta potential, FT-IR, and 13C solid NMR spectrum analysis. The results show that the inorganic substance inlaid in coal are dissolved by ni- tric acid, which results in the decrease of coal ash content and increase of pore volume and pore size. Furthermore, there exist obvious chemical reactions between nitric acid and the functional groups of coal including aromatic ring carboxylation, side chain alkyl of aromatic ring oxidation and aromatic ring nitration. Among these reactions, some led to the increase in content of carboxyl, aliphatic carbon connected with O and humic acid carbon, while others caused the reduction of aromaticity, methyl carbon, substituted aryl carbon and side chain.
基金Financial support for this work, provided by the National Natural Science Foundation of China (No.50834002)the National Eleventh Five-year Plan Science and Technology Key Project (No. 2006BAK03B05), is gratefully acknowledged
文摘Gas products from the process of coal oxidization and spontaneous combustion have been studied at different temperatures with FTI spectroscopic tests. With temperatures rising to about 30~100 ℃, water and carbon dioxide gas were formed and from about 105~150 ℃, carbon monoxide was produced. Using the DFT B3LYP method with a 6-311G basis set, the reaction system, where spontaneous combustion between coal and oxygen occurs and produces water and monoxide, has been studied, with the geometric configuration for all stagnation points on the potential reaction energy surface optimized. With a frequency analysis and an IRC method, transient formations were tested. Our results indicate that in the reaction of coal oxidization and spontaneous com-bustion producing carbon dioxide and water, oxygen molecules attack carbon atoms of the terminal of the propyl alcohol group on the lateral chain of benzene rings, which causes this propyl alcohol group to produce the acid (-CH2-CH2-COOH) group and water. This acid group continues its break up into carbon dioxide and the (-CH2-CH3) ethyl group. We have come to the conclusion that this water-and-carbon dioxide-production reaction is spontaneous, based on the observation of the energy released by the reaction.
文摘This research presents the results of system validation tests for an SOFC power system. In the study, the system was heated up without electric device, i.e., the fuel providing the required thermal energy through an integrated BOP （balance of plant）. The ex-situ experiments, without an SOFC stack installed in the system, were fast conducted to investigate the operability of a BOP apparatus. It was found that the BOP possessed high conversion rates for both steam reforming and water gas shift reactions. The total fuel concentration of hydrogen and carbon monoxide from the reformer was around 91.2%. The system validation tests showed that, with the natural gas as fuel, the output power from the stack reached to 1,060 W, while the fuel utilization efficiency and electrical efficiency were 67.16% and 45.0%, respectively. A steady 600-hour system operation test was carried out at an average system temperature of 694℃. Of which, a 36-cell stack was employed for the test. Meanwhile, the current, voltage and output power were 26 A, 32.3 V and 840 W, respectively, and its electrical efficiency was around 33.4%.
基金supported by National Natural Science Foundation of China(51074170)Shaanxi Key Technology R&D Program(2016GY-147)+1 种基金Key Laboratory of Coal Resources Exploration and Comprehensive UtilizationMinistry of Land and Resources Open Research Topic(KF2016-3)
文摘Coal gangue was calcinated under air, nitrogen, carbon dioxide, air-hydrogen, and hydrogen atmospheres. The effects of different calcination temperatures and atmospheres on the mineral composition of activated coal gangue were investigated by X-ray diffraction. Moreover, the acid leaching kinetics of aluminum oxide from coal gangue was investigated with sulfuric acid. It showed that the air atmosphere promoted kaolinite decomposition during coal gangue calcination. The hydrogen atmosphere promoted the activation and decomposition of kaolinite at reaction temperatures exceeding 650℃. The carbon dioxide atmosphere eliminated the influence of residual carbon on coal gangue. When the ratio of acid/coal gangue was 1.5 and reaction temperature was 650℃, the sulfuric acid leaching rate under air, air-hydrogen, carbon dioxide, hydrogen and nitrogen atmospheres were 93.66%, 90.90%, 84.06%, 81.91% and 77.54% respectively. The acid leaching reaction process conformed to unreacted shrinking core model of particle unchanged, and was controlled by the interracial chemical reaction. The reaction kinetic equation for the leaching process was 1-（1-x）1/3=kt with an apparent activation energy of 48.97 kJ/mol.
