Abstract: Five coking coals and 44 groups of blended coals were studied, and the coking experiments with coal cup were completed using a 40 kg small coke oven. According to the yields of heavy component, dense medium component and loose medium component (YHC, YDMC and YLMC) obtained by all-component separation as well as the FT-IR parameters of I3 and I4 which reflect hydrogen bond association, aliphatic chain length and branched degree, the prediction model for coke quality was established with the BP neural network. Then, the characteristics of the model were discussed and the coking mechanism by the new model was analyzed. The results show that using new defined coal structure parameters to predict coke quality has some advantages. The predicted and measured values of coke formation rate (CR), micro-strength (MSI), reactivity of particulate coke (PRI) and post-reaction strength (PSR) are in good agreement, and the fitting correlation coefficient of y versus x reaches 0.986, 0.982, 0.956 and 0.926, respectively. The prediction results of CR, MSI and PRI by the model are good with the mean variation of nine samples being 0.53%, 1.58% and 1.28%, respectively. However, the prediction result of (PSR) is poor with the mean variation being 12.22%. The results can provide a good foundation for the establishment of a new method for coal blending.
Abstract: Reaction behavior of Naomaohu (NMH) coal in tetralin was carried out under atmosphere of H2. Hydrogen transfer in complex multi-phase system of direct coal liquefaction were discussed. The influence of phase transition process of iron-based catalyst on liquefaction performance was investigated using X-ray diffraction, saturate magnetization and scanning electron microscope. The results show that NMH coal presents good liquefaction performance at 420℃ and 17 MPa. Active phase Fe7S8 plays catalytic role during initial reaction and changes into nonactive phase-Fe9S10 and FeS later. High hydrogenation activity of catalyst and long residence time are beneficial to hydrogenation of preasphaltene and asphaltene into light oil. Catalyst promotes the activation of H2 transferring to coal pyrolysis products and solvent. Catalyst promotes the hydrogen in solvent to transfer to coal pyrolysis products as well. The contribution to activated hydrogen from solvent is twice as that from H2 in the condition of the experiment. Hydrogen transferring from H2 to solvent changes little with temperature, pressure and time. Activated hydrogen from H2 and solvent is proportional to the conversion of coal and asphaltene to oil and gas.
Abstract: The slagging mechanism of the Jincheng coal in the ash-agglomerate fluidized bed gasification was explored. A typical Jincheng coal sampled from Shanxi, China was prepared into different particle size and the XRF, XRD, AFT, SEM and FactSageTM were employed to study the influence of particle size on the ash content, chemical and mineral composition and ash fusibility. The results indicate that the ash chemical composition and AFTs vary little with size below 6 mm. For the pulverized samples below 0.2 mm, there are apparent differences in the chemical composition and mineral composition, especially in Fe2O3. Both AFT results and SEM observations show that the sample with particle size less than 45 μm has a significantly higher melting temperature than the other three samples. The slag contents calculated with FactSageTM are consistent with the AFT results and SEM observations, which indicates that the change of ash melting behavior with particle size results from the change in chemical composition. The ternary phase diagram of SiO2-Al2O3-Fe2O3 can be used successfully to explain the mechanism of the change of ash melting behavior with particle size for Jincheng coal.
Abstract: Differences on organic/inorganic structures and fuel properties between sewage sludge-derived hydrochar and different-rank coals were investigated and compared with the help of FT-IR, XRF and XRD technologies. Meanwhile, the combustion behavior under various blending ratio and its synergistic effects was identified via TG and deviation analysis. The results demonstrates that the organic structures and combustion behaviors of hydrochar are similar to those of coals, which not only improves the combustion properties of sewage sludge, but also enhances the synergistic effects in co-combustion of hydrochar and coals. During the co-combustion process, light volatiles and (alkaline) alkaline-earth metals in hydrochar could accelerate the weight loss rate for coals, reaching 4.4%-16.1%, 1.9%-9.4% and 4.8%-12.1% for lignite, bitumite and anthracite, respectively. In general, the blends with 30% hydrochar and 70% lignite or 50% hydrochar and 50% lignite are better than other blends in terms of comprehensive combustion evolutions.
Abstract: A core-shell composite zeolite (HY/silicalite-1) was prepared by modifying HY zeolite with silicalite-1 and characterized by X-ray diffraction (XRD), Scanning electron microscope (SEM), Transmission electron microscope (TEM), N2 sorption and IR spectra of pyridine adsorption (Py-FTIR); the catalytic performance of HY/silicalite-1 composite zeolite in the hydrolysis of cellulose was then investigated in comparison with that of HY. The results show that the crystallization time has a significant influence on the crystal growth of the HY/silicalite-1 composite zeolite and the relative content of two components. With the optimum crystallization time of 16-24 h, a core-shell structure for the HY/silicalite-1 composite zeolite is achieved, where the silicalite-1 crystal grows over the surface of HY zeolite; with the prolongation of the crystallization time, the morphology of the composite zeolite changes from rough turbid to smooth and eventually to scale-like surface. The amount of Br nsted acid sites decreases first and then increases with the increase of the crystallization time, whereas the amount of Lewis acid sites changes in the opposite direction. In particular, the HY/silicalite-1 composite zeolite obtained with a crystallization time of 24 h exhibits excellent catalytic performance in the hydrolysis of cellulose to glucose; over it, the yield of glucose reaches 45.8% at 130℃, much higher than the value of 28.0% over the HY zeolite.
Abstract: A series of Pt/ZSM-22 bifunctional catalysts were prepared by using different metal precursor solvents including water, methanol, acetone and acetic acid. The phase structure, texture properties, metal properties and acidity were systematically investigated by XRD, BET, TEM, CO-chemisorption, CO-FTIR and Py-FTIR. The effect of metal precursor solvents on n-dodecane isomerization was also studied. The results indicate that the solvents with different polarities lead to different locations of Pt particles. Part of Pt particles locate on ZSM-22 when methanol, acetone and acetic acid are used as solvents, and the interaction between Pt and acid sites lead to the electron-deficient of Pt. However, the Pt particles almost locate on the Al2O3 binders when water is used as solvent, and their electronic properties are little affected. Higher activity and selectivity are achieved when Pt particles locate on ZSM-22 in the n-dodecane isomerization reactions. These results indicate that shorten the distance between acid sites and metal sites can expedite the diffusion of reactants and isomerized intermediates to proceed dehydrogenation and hydrogenation reactions.
Abstract: PtRuIn/C electrocatalysts (20% metal loading by weight) were prepared by sodium borohydride reduction process using H2PtCl6·6H2O, RuCl3·xH2O and InCl3·xH2O as metal sources, borohydride as reducing agent and Carbon Vulcan XC72 as support. The synthetized PtRuIn/C electrocatalysts were characterized by X-ray diffraction (XRD), energy dispersive analysis (EDX), transmission electron microscopy(TEM), cyclic voltammetry (CV), chronoamperommetry (CA) and polarization curves in alkaline and acidic electrolytes (single cell experiments). The XRD patterns show Pt peaks are attributed to the face-centered cubic (fcc) structure, and a shift of Pt (fcc) peaks indicates that Ru or In is incorporated into Pt lattice. TEM micrographs show metal nanoparticles with an average nanoparticle size between 2.7 and 3.5 nm. Methanol oxidation in acidic and alkaline electrolytes was investigated at room temperature, by CV and CA. PtRu/C (50:50) shows the highest activity among all electrocatalysts in study considering methanol oxidation for acidic and alkaline electrolyte. Polarization curves at 80℃ show PtRuIn/C (50:25:25) with superior performance for methanol oxidation, when compared to Pt/C, PtIn/C and PtRu/C for both electrolytes. The best performance obtained by PtRuIn/C (50:25:25) in real conditions could be associated with the increased kinetics reaction and/or with the occurrence simultaneously of the bifunctional mechanism and electronic effect resulting from the presence of Pt alloy.
Abstract: A series of hydrotalcite-like derived MgAlOx (MA) and CuMgAlOx (CMA) catalysts with various M2+/Al3+ molar ratios were prepared and evaluated by the aldol condensation reaction of formaldehyde and acetaldehyde and Guerbet reaction of methanol and ethanol, respectively. The acidity and the alkalinity as well as the surface copper species of catalysts were characterized by NH3/CO2-TPD, XPS, H2-TPR and H2-TPD techniques. The results show that the catalytic performance of Guerbet reaction of methanol and ethanol is related to the surface Cu0 species and the number of moderate basic sites. Increasing the specific surface area of Cu0 is beneficial to the dehydrogenation of methanol and ethanol to formaldehyde and acetaldehyde. The increase of the amount of moderate basic sites can promote the condensation reaction of formaldehyde and acetaldehyde.
Abstract: ZnAl-LDHs was prepared by in-situ synthesis method on the surface of γ-Al2O3, and then a series Ce/Cu/Zn-Al catalysts were prepared by ordinal wet impregnation method. All the catalysts were characterized by XRD, BET, H2-TPR and XPS to investigate the effects of calcination temperature on the surface structure of Ce/Cu/Zn-Al catalyst and its catalytic performance in methanol steam reforming. The results showed that calcination temperature mainly influenced the specific surface area of copper, surface oxygen vacancy content and the interaction between Cu and Ce. When the calcination temperature is 500℃, the specific surface area of Cu is larger, the content of oxygen vacancy is higher and the interaction between Cu and Ce is stronger. Therefore, the catalytic activity of the catalysts for methanol steam reforming is the best. When the calcination temperature rises to 700℃, the Cu species mainly exist in the form of stable CuAl2O4 spinel, which is not conducive to the reaction of methanol steam reforming, resulting in lower catalytic activity.
Abstract: Mg-La-HY-SBA-15 zeolite prepared by separate-step impregnation method was used to catalyze alkylation of phenol with methanol. The porous structure and acid property were characterized by SEM-EDS, Py-FTIR and others.The results found that Mg was successfully supported on La-HY-SBA-15 zeolite. Mg-La-HY-SBA-15 had micro-mesoporous structures. Compared with mono-mental modification, bimental modification reduced the amount of total acid and gained more total Lewis acid. At the same time, the selectivity and yield of o-cresol were increased.
Abstract: CoMo/γ-Al2O3 catalyst for hydrodesulfurization (HDS) were prepared by equal volume impregnation method with and without the presence of pulsed electronmagnetic field (PEMF). Experimental results revealed that the catalyst prepared by PEMF with a voltage of 200 V exhibited higher catalytic activity for hydrodesulfurization of thiophene, 2-methythiophene and benzothiophene than the catalyst prepared by conventional impregnation. The surface morphology and physico-chemical properties were characterized by using BET, XRD, H2-TPR and TEM techniques, respectively. The results showed that appropriate PEMF treatment promotes the active component dispersion on the γ-Al2O3 surface by interacting with the charged particles in reaction system. The interaction between the support and the active species MoO3 is weakened and thus facilitates the reduction of the catalyst and the formation of CoMoS active phase.
Abstract: Effect of Fe and point deficiency on adsorption behavior of NH3 on coke surface was studied using density functional theory and graphene model with periodic boundary conditions. The results show that the adsorption of NH3 on surface of point-defective graphene belongs to physical adsorption with binding energy of -0.381 eV. The adsorption of NH3 on surface of Fe-modified-graphene belongs to chemical adsorption with energy of -1.442 eV. The adsorption energy of NH3 in the presence of Fe atom or point defect is greater than that of NH3 on the surface of intact graphene. In addition, coexistence of Fe atom and point defect has a synergistic effect on adsorption of NH3 with binding energy of -3.538 eV, which is much higher than the sum of adsorption energy of NH3 in the presence of the two alone. There is more charge transferring among Fe atom, graphene surface and NH3 molecule, which can explain the synergistic effect of coexistence of Fe and point defect.
Abstract: A manganese and cerium oxide catalyst was prepared through sol-gel method. Effects of the concentration and type of alkali metals on performance of the Mn-Ce/TiO2 catalysts were investigated in selective catalytic reduction of NO with NH3. The cause of the alkali metal poisoning of the catalyst was studied and the influence of sodium salt deposition on the activity retention fraction under different reaction conditions was further studied. The catalysts were characterized by scanning electron microscope (SEM), BET surface area, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), respectively. The results show that alkali metals exhibited an inhibiting effect on the selective catalytic reduction (SCR), and the deactivation rate of Mn-Ce/TiO2 catalyst caused by potassium poisoning was higher than that by sodium poisoning. The NO conversion was decreased from 91.2% to 62.0% at a temperature of 160℃, when the potassium content was 2%. This is mainly because the presence of the alkali metal resulted in a reduction of the specific surface area of the catalyst, and the specific surface area of the potassium poisoning of the catalyst was reduced by 34.2%. The alkali metal poisoning could cause blockage of the micropores on the surface and the transfer from anatase to rutile phase of the catalyst. The effect of alkali metal on the retention fraction of the Mn-Ce/TiO2 catalyst indicates that the particle size of the catalyst had slight effect on its activity retention fraction. The selective catalytic reduction (SCR) activity of the Mn-Ce/TiO2 catalyst increased along with the temperature. While the content of alkali metal decreased, the retention rate of active metal increased. The inhibitory effect of Na2SO4 and NaCl on the denitrification activity of Mn-Ce/TiO2 catalyst was more significant than that of NaNO3.
Abstract: The NO removal using oxidation of free radicals produced from Fe2+ and heat synergic activation of oxone in a gas-liquid impinging stream reactor was investigated. The effects of several main process parameters (solution temperature, Fe2+ concentration, oxone concentration, solution pH value, NO inlet concentrations) on NO removal were examined. The reaction products and free radicals were also detected and analyzed. Based on the comparative study of different systems, detection of reaction products and capture of active free radicals, the mechanism and reaction pathways of NO removal process were revealed. The results indicate that the increase in oxone concentration, solution temperature or Fe2+ concentration elevates the NO removal efficiency, but the increase in the solution pH value or NO inlet concentration reduces the NO removal efficiency. A synergistic effect between Fe2+ and heat, which activates the oxone to generate sulfate radicals and hydroxyl radicals, was observed. It reveals that the sulfate radicals and hydroxyl radicals are the primary reactive oxidants, and oxone is the complementary oxidant for NO removal. The synergistic activation system of Fe2+ and heat has much higher NO removal efficiency than other systems.
Abstract: The Mg-Al hydrotalcites used as the support were prepared by precipitation method, and then the catalysts with different amount of doped potassium, (xK/MgAlO) were prepared by impregnation method. The effects of K on the structure and catalytic activity of the xK/MgAlO catalyst were investigated in SO2 containing gases. The key mechanism of K-doped (xK/MgAlO) catalysts to reduce the soot ignition temperature during the reaction was illustrated. The differences of the crystal structure between calcined and uncalcined Mg-Al hydrotalcite were studied by X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, and the transient response method. The experimental results showed that the 3R layered structure of Mg-Al hydrotalcite disappeared while the spinel phase appeared, and the layered structure collapsed into spherical particles after calcination. Potassium doping formed more oxygen vacancies that are conducive to the combustion of diesel soot, decreased the temperature of soot combustion from 380 to 253℃ though in SO2 atmosphere and significantly enhanced the conversion efficiency of NOx.
Supervisor：Chinese Academy of Sciences
Sponsors by：Shanxi Institute of Coal Chemistry, Chinese Academy of Sciences Chinese Chemical Society
