Abstract: Coal hydrogasification, divided into coal pyrolysis and char hydrogasification, was studied in a fixed bed reactor.FT-IR gas analyzer, Laser Raman analyzer and XRD were applied to analyze the relationship between gas production component of coal pyrolysis and microstructure change of char, and the influence of microstructure change of char on char hydrogasification reactivity.The results show that pyrolysis temperature has an obvious effect on microstructure and hydrogasification reactivity of char.With rising temperature, the ratios of Raman band area AD1/AG, AD2/AG, AD3/AG, AD4/AG gradually rises, and the ratio of AG/AAll decreases within 400-800℃ and increases within 800-900℃.It indicates that graphitization process of char is obviously emerged due to the increase of relative amount of disordered carbon in pyrolysis.The results of XRD analysis are in accordance with those of Raman analysis.The interplanar crystal spacing d002 increases within 400-800℃.d002 decreases and L002 increases sharply within 800-900℃.By fitting the Raman area ratio formula (aAD1/G+bAD2/G+cAD3/G+dAD4/G) with hydrogasification reactivity (τ0.5), the obtained factor represents the hydrogasification reactivity of carbon microcrystal.The factor is bigger, and the reactivity of carbon microcrystal is better.
Abstract: Shengli brown coal was gasified at 800-900℃ in a simulated entrained-flow reactor, φ 80×3 000 mm.The physical structure and functional groups of char were tested by infrared spectroscopy, X-ray photoelectron spectroscopy and Raman spectroscopy while coal gas was tested by gas on-line analysis instrument in order to explore the mechanism of promoting effect of oxidation reaction on steam gasification reaction.The results show that the synergy effects can be explained by dissociated adsorption reaction mechanisms of steam gasification reaction and semi-coke pore structure features under different atmospheres.The oxidation reaction can make microspores number, specific surface area, pore volume and adsorption capacity of the char particles greatly increase and more carbon active sites expose by producing microspores, developing mesopores;it also prompts small groups as-CH3, -CH2-, ＞ C=O & ＞ C-O-fractured and generation of hydrogen free-radical and carboxyl.All these promote steam gasification reaction rate, especially at a higher water vapor content or temperature.Meanwhile, the oxidation reaction can change the relative content of CO2, CO, H2 and internal energy of steam molecules and activated carbon atoms, in favor of steam gasification reaction.
Abstract: The pyrolysis experiments of YNZX coal with 10% CaO at 800-1 200℃ were conducted in a high frequency furnace.The effects of adding CaO on the release and transformation of arsenic and sulfur during pyrolysis have been investigated with the aid of sequential chemical extraction, XRD, SEM-EDX, and XPS.The results show that CaO can inhibit the release of arsenic and sulfur significantly.The retention rate to arsenic amounts to 41.19% at 800℃, and that to sulfur reaches 39.89% at 1 000℃, there is a negative correlation between the two retention rates.The formation of As-Ca compounds and CaS accounts for the decrease of release rates of arsenic and sulfur.The sulfur is enriched on the surface of CaO, which occupies more active adsorption sites after pyrolysis and inhibits the retention of arsenic, most sulfur is presented as sulfides in char and the amount of sulfites increases after adding CaO.
Abstract: The occurrence and thermal transformation behaviors of AAEMs (alkali and alkaline earth metal species) in a typical Xinjiang coal (Wucaiwan) were systematically investigated.The raw coal sample was primarily separated to four fractions based on different densities by float-sink experiments using organic heavy solutions.Subsequently, the BSE-EDX (backscattered electron-energy dispersive X-ray detector) and XRD were employed to analyze the mineral matters in coal fractions.Moreover, the thermal transformation behaviors of minerals in coal were simulated using FactSage.The results show that the active minerals (i.e., AAEMs) in coal vary with the flotation density and exhibit quite different transformation characterizations.Samples with density of 1.40-1.50 g/cm3 are the major fraction (70%) for Wucaiwan coal.The Na and K exist principally in the lower density (-1.40 g/cm3) fraction;in contrast, the AAEMs are combined with the alumina-silicate in the high density (+1.50 g/cm3) fraction.Additionally, Ca is mainly in the form of calcite;and kaolinite and quartz are enriched in the high density fraction.Less Na could release at lower heat treatment temperature (500℃);thus the release amounts of Na in four fractions present less difference.The majority of Na is volatilized from the low density coal sample at 815℃;but for the high density coal samples the clay (mainly kaolinite) and quartz could capture Na and restrain its release.According to the FactSage calculation, the NaCl is found to be still stable in the coal ash at 550℃;it would start evaporate over 550℃ and generate NaAlSiO4.The NaCl would vanish at 620℃ and the NaAlSiO4 gradually becomes constant.Moreover, at the temperature range of 500-815℃, Ca is mainly in the form of CaSO4 and Ca-Si-Al, while Mg varies in several forms.
Abstract: Using 4 inferior residual oils as raw materials, the effect of feedstock properties on the characteristics of coke formation during initial thermal conversion process was studied.The results show that the influence for coke induction period of different oils affected by temperature can be measured with the sensitivity parameters.The shorter the coke induction period of the residue, the bigger the sensitivity parameter.The coke induction period has a higher decrease rate with the reaction temperature rising.The coke formation property generally depends on feedstock's basic properties, and the influence of various properties of inferior residual oils on coke formation is different under the same reaction conditions.Carbon residue, ash, relative molecular mass, asphaltene precipitation onset point and stability parameter have strong correlations with the coke induction period, especially for the colloidal stability of oil reflected by asphaltene precipitation onset point and stability parameter.The colloidal stability of the inferior residual oils is related to the coke formation characteristics.The worse the stability of the residue, the more likely the coke is to form.The coke forming process is a gradual destruction of the colloid system during thermal reaction.
Abstract: SBA-16 molecular sieve was synthesized by soft template method and modified with ammonia under high temperature to obtain the nitrogen-incorporated SBA-16(SBA-16-N);with SBA-16 and SBA-16-N as the supports, nickel based catalysts (Ni/SBA-16 and Ni/SBA-16-N) were prepared by the incipient impregnation method.The related supports and Ni-based catalysts were characterized by transmission electron microscope, X-ray photoelectron spectroscopy, nitrogen physisorption, carbon dioxide temperature programmed desorption, X-ray diffraction and thermogravimetric analysis;the catalytic performance of Ni/SBA-16 and Ni/SBA-16-N in the reforming of methane with carbon dioxide was comparatively investigated under 500-800℃.The results indicate that after the nitriding modification, the Ni/SBA-16-N catalyst exhibits much higher activity in methane reforming with CO2 and higher selectivity to syngas than the Ni/SBA-16 catalyst without nitridation treatment.During the nitriding modification at high temperature, O atoms in the SBA-16 skeleton are partially replaced by N atoms, which can strengthen the support basicity and the interaction between the support and the nickel nanoparticles.All these may promote the dispersion of nickel nanoparticles on SBA-16-N and the adsorption of CO2 on Ni/SBA-16-N, leading to the improvement of the activity and stability of the Ni/SBA-16-N catalysts in methane reforming with carbon dioxide.
Abstract: The template-free ZSM-5 was prepared by hydrothermal synthesis and then modified by tetramethoxysilane (TMOS).The structure, morphology, and acidity of all samples were studied by various techniques, such as XRD, SEM, 29Si MAS NMR, 27Al MAS NMR, NH3-TPD, BET and UV-vis DRS.Comparing with the zeolites synthesized by traditional method, the template-free ZSM-5 exhibited the analogical acidity, morphology and structure, but obvious difference in acid distribution.Due to the absence of the structure directing agent, the template-free ZSM-5 possessed more acid sites situated at pore channels of catalyst and less acid sites stayed at the intersection of straight and sinusoidal channels.Consequently, the shape selectivity enhanced significantly.After TMOS modification, the non-shape acid sites located at the external surface were covered by a single SiO2 layer.The template-free ZSM-5 achieved the highest total yield of ethylene and propylene, longest working life-span and lowest level of coke deposition among the studied catalysts, ascribing to the suppression of the side reactions.
Abstract: For improving the oxygen storage/release capacity of ceria-zirconia solid solution, Ce0.5Zr0.5O2-Al2O3 mixed oxides were prepared by a co-precipitation method and applied in the oxidative dehydrogenation of ethylbenzene to styrene with carbon dioxide.Ce0.5Zr0.5O2-Al2O3 mixed oxides were characterized by powder X-ray diffraction, Raman spectroscopy, N2-sorption, H2 temperature-programmed reduction, and X-ray photoelectron spectroscopy.Results show that Al2O3 acts as a diffusion barrier.The addition of Al prevents the growth of Ce0.5Zr0.5O2 crystallite size, increases the specific surface area and oxygen storage capacity of Ce0.5Zr0.5O2-Al2O3 mixed oxides.The specific surface area and oxygen storage capacity of Ce0.5Zr0.5O2-Al2O3 mixed oxides are 51.8 m2/g higher and 69.4 μmol/g more than those of Ce0.5Zr0.5O2 mixed oxides.The ethylbenzene conversion over Ce0.5Zr0.5O2-Al2O3 mixed oxides is about 10% higher than that over Ce0.5Zr0.5O2 mixed oxides after 5 h reaction.
Abstract: Three-dimensional graphene (PGO) was synthesized by spay-drying method.Pt/PGO catalyst was prepared through the improved liquid phase reduction method.The samples were characterized by XRD, BET and TEM.The results indicated that PGO was a three-dimensional crumpled structure material with 4-6 μm in length and 2.0-3.0 μm in width and the Pt nanoparticles with 4.2 nm were highly dispersed on the surface of PGO.The electro-catalytic activity and stability of the catalysts towards methanol electro-oxidation were investigated using cyclic voltammetry and chronoamperometry.The as-prepared Pt/PGO catalyst exhibits higher electro-catalytic activity and good stability during methanol electro-oxidation in comparison to Pt/GO catalysts.The enhanced catalytic performance is attributed to the high specific surface area of the 3D formation and utilization efficiency of Pt during methanol electro-oxidation.
Abstract: ZSM-5 zeolite with a SiO2/Al2O3 mol ratio of 50 as the raw material was treated either by adding tetrapropylammonium hydroxide solution for secondary crystallization after pre-treating with Na2CO3 solution or directly by Na2CO3/TPAOH mixed solution, to prepare the micro-mesoporous hierarchical HZSM-5 catalyst;the catalytic performance of resultant micro-mesoporous HZSM-5 in thiophene alkylation was then investigated.The results showed that if the raw ZSM-5 material is first pre-treated with 4 mol/L Na2CO3 and then crystallized for the second time in the presence of 0.3 mol/L TPAOH and at 170℃ for about 24 h, the resultant micro-mesoporous HZSM-5(CO32--TPA+, 0.3-24-170) has a moderate pore diameter and acidity and exhibits the highest conversion of thiophene (99.1%) in alkylation.However, if the raw ZSM-5 is treated by the mixed solution of Na2CO3 and TPAOH, the dissolved SiO2 may block the pores and channels, leading to lower acidity and smaller pores, which is not suitable for the thiophene alkylation.
Abstract: The yttrium (Y) modified unsupported Yx-Ni2P catalysts were prepared by one step method and stepwise method (x refers to mol ratio of Y to Ni), respectively.The catalysts were characterized by X-ray diffraction (XRD), N2 adsorption specific surface area measurements (BET), CO uptake and X-ray photoelectron spectroscopy (XPS).The effects of preparation methods on thehydrodesulfurization (HDS) property of the catalysts were investigated by using dibenzothiophene (DBT) as the model compound.The results show that the addition of Y can suppress the formation of Ni5P4 phase and thus promote the formation of active Ni2P phase.The addition of Y can dramatically increase the surface area and pore volume, effectively improve the HDS activity of nickel phosphide catalyst.The Yx-Ni2P catalysts prepared by these two methods with Y/Ni mol ratio of 0.10 exhibited the highest HDS activity.As compared to the stepwise method, the one step method which obtained catalysts possessed a larger specific surface area with high pore volume, a lower surface P/Ni mol ratio, a larger CO uptake and more exposed active Ni sites as compared to stepwise method.As a result, it showed a higher HDS activity.At a temperature of 340℃, a pressure of 3.0 MPa, a H2/oil volume ratio of 700 and a weight hourly space velocity (WHSV) of 1.5 h-1, the conversion of DBT over Y0.10-Ni2P catalyst prepared by one step method reached 97.7%, which was an increase of 5.4% comparing with the Y0.10-Ni2P catalyst prepared by stepwise method (92.3%).
Abstract: The catalysts of supported copper oxide were prepared by impregnation method, which were characterized by XRD, TG-MS, XPS, NO-TPD, NH3-TPD and H2-TPR and the effect of carrier on the performance of catalysts for the selective catalytic reduction of NO with NH3 at low-temperature in the presence of oxygen was investigated.The results show that the copper species exist in the form of CuO and Cu2O on carriers.The dispersion and oxidation state of copper species, the acidity and redox ability of the catalysts and the performance of adsorption/desorption are affected by the carriers.The Cu/HZSM-5 catalyst with highly dispersed copper speicies has excellent redox properties, suitable acidity and acid capacity, and good adsorption/desorption performance for reactants, which shows a good catalytic activity in the NH3-SCR denitrification reaction.The reaction temperature is lower, T50 and T90 is 137 and 165℃, respectively, and the active window temperature is wide.The temperature range for the NO conversion of over 90% is 165-358℃.
Abstract: A series of MgAPO-5 molecular sieves with a wide range of Mg/P mol ratios in the gel was synthesized by a hydrothermal process.Using MgAPO-5 as acidic supports, the bifunctional NiW/MgAPO-5 catalysts were prepared by impregnation method, and applied to the hydrocracking of tetralin to produce BTEX.The synthesized MgAPO-5 molecular sieves and NiW/MgAPO-5 samples were characterized by XRD, N2 adsorption, SEM, NH3-TPD, Py-FTIR and H2-TPR.The results exhibit that the Mg/P mol ratio has a great influence on the unit cell parameters, morphology, the Mg content and the acidity of MgAPO-5 samples, and the ion of Mg2+ is incorporated into the framework.In the hydrocracking of tetralin, with the same amount of NiW, the activity of NiW/MgAPO-5 is primarily controlled by the acidic strength of MgAPO-5.The selectivity of BTEX was determined by the combined effect of the acidity of MgAPO-5 and the (de) hydrogenation function of NiW.The highest conversion is achieved with the Mg/P mol ratio of 0.05, and the best BTEX selectivity is obtained with the Mg/P mol ratio of 0.03.
Abstract: The calcination process of precipitated iron based Fisher-Tropsch synthesis catalysts was optimized by the design of experiment (DOE) tools.And the molecular simulation model and the particle growing model were proposed.The results showed that the catalyst pore volume decreased, the bulk and skeleton density of the catalyst increased, and the attrition resistance of the catalyst improved with the calcination temperature and time increasing.The smaller the BET surface of the catalyst, the smaller the attrition of the catalyst is.The attrition and density of the catalyst have a inverse linear relationship.The bonding strength of Cu, Si with Fe by O atom and the particle size can be adjusted by calcination optimization, thus got high F-T activity and good stability.In our experiments, the optimized calcination temperature is 560℃.
Abstract: CuMnCe/TiO2-Al2O3 catalysts with different TiO2 contents were prepared by the co-impregnation method and characterized by BET, XRD, XPS and H2-TPR techniques.The catalytic performance in methane deoxidation reaction were investigated using CGK-5A fixed bed reactor.Results showed that doping some TiO2 in the Al2O3 support has no effect on the crystalline structure of the active ingredient.But it can effectively improve Al2O3 support sintering resistance and thermal stability, furthermore, it increases content of Ce3+/(Ce3++Ce4+) in the CuMnCe/Al2O3 catalysts, which improves the mobility of oxygen.Besides, the content of adsorbed oxygen Osur/(Osur+Olatt) and reducible species in the catalyst surface are increased.Thus, effectively, doping some TiO2 into the Al2O3 support improved the catalytic activity of deoxygenation catalyst for methane combustion.CuMnCe/4% TiO2-Al2O3 exhibited optimum catalytic activity and oxygen conversion rate reached 100% at 387℃.
Abstract: The kinetic and deactivation kinetic models of methane catalytic cracking were established based on the data of thermal gravimetric analyzer.The kinetic model of methane catalytic cracking was established by the data of initial hydrogen production rate under the condition of no carbon deposition.The deactivation kinetic model was established by the reduced rate of methane catalytic cracking.The experiment was carried out over Ni-Mg composite catalyst, at the temperature of 535, 585, 635℃ and the methane partial pressures were 104, 2×104, 3×104 Pa.The result shows that the reaction order and activation energy were 0.5 and 82 kJ/mol, the deactivation order and activation energy were 0.5 and 118 kJ/mol respectively.The multi-walled carbon nanotubes were all produced under the experimental conditions.
Supervisor：Chinese Academy of Sciences
Sponsors by：Shanxi Institute of Coal Chemistry, Chinese Academy of Sciences Chinese Chemical Society
