Abstract: The co-thermal dissolution (CTD) properties of Shenfu coal (SC) and rice straw (RS) in 1-methylnaphthalene (1-MN) at different temperatures were studied. It is found that RS gives much higher of thermal dissolution yield (TDY), suggesting its high thermal dissolution (TD) activity. But much amount of gas is produced in the TD process of RS, resulting in the low thermal soluble yield (TSY). For the TD of SC, although the TDYs of SC are much lower than those of RS, but the differences between TDY and TSY from the TD of SC are much smaller than those from the TD of RS. CTD of SC and RS shows that there exists synergistic effect which is the function of temperature. At 320 to 340℃, the TSYs have positive synergistic effect. The experimental results are larger than corresponding calculated weighted mean values of the individual TD of SC and RS. While at all the TD temperatures studied, TDYs give negative synergistic effect. The largest enhancements in TSY of 7.9% comparing with corresponding calculated weighted mean values of the individual TD of SC and RS are obtained at 320℃. The mechanism of synergistic effect produced in CTD was discussed based on the characterization of TD soluble fractions.
Abstract: The Fourier transform infrared (FT-IR) spectroscopy was applied to investigate the functional groups of Shuicheng lignite, and the simultaneous thermogravimetry-mass spectrometry (TG/MS) at heating rate of 10 ℃/min was used to investigate the pyrolysis behavior of coal. The instantaneous evolution of the gaseous products (H2, CH4, H2O, CO, CO2) was studied by means of temperature-programmed pyrolysis experiments. The pyrolytic generation characteristics of methane was specially analyzed. Five peaks were fitted and the kinetic parameters were calculated by the fitting of curves. By the kinetic analysis combined with structure analysis, pyrolysis characteristics and the evolution features of other volatiles during pyrolysis, it is found that the lowest temperature peak represents the desorption of adsorbed methane in coal and the other four peaks are the results of methane generation during pyrolysis, which involves four types of reactions.
Abstract: The combustion properties of 3 fine chars derived from fluidized bed gasification of coals with different rank were studied in a thermogravimetric analyzer (TGA). In addition, the influence of ash on combustion reactivity was investigated, and the processes were analyzed using three kinetic methods to obtain the kinetic parameters. The results suggest that the existence of volatile in fine char from low-rank lignite reduces its ignition temperature, while the decomposition of inherent minerals at relatively high temperature leads to a second peak in the DTG curve. The ashes of fine chars have an inhibiting influence on burn-out ability and comprehensive combustion reactivity. The kinetic analysis indicates that the activation energy increases with the increasing burnout extent. Compared with Coats-Redfern and Ozawa-Flynn-Wall methods, the Vyazovkin method fits the experiment results best.
Abstract: Mineral conversion in heating process was studied by low temperature ashing, high temperature ashing and XRD. The results show that the original minerals in Zhundong coal mainly include calcite and kaolinite. With the increase of combustion temperature, they transform into fusible minerals such as fayalite and calcium. In addition, refractory minerals, ettringite and grossular, generated in ash samples, result in higher ash melting points with the decrease in SiO2/Al2O3 ratio which was adjusted by adding kaolinite and alumina into the raw coal.
Abstract: Coal samples were activated using a γ-ray as an irradiation source. Electro spin resonance (ESR), gas chromatography (GC) and linear sweep voltammetry (LSV) were employed to investigate the effects of γ-rays radiation on the change of free radical and structure of coal. The results show that γ-rays irradiation could promote the cleavage of alkane chains and heteroatoms in coal, leading the generation of free radicals and gas with low molecular weight, such as hydrogen, methane and ethane. Radical concentration reaches the maximum at 40 kGy. The increase of free radical could improve the electro-reduction of coal. The current density is reached the maximum at 40 kGy.
Abstract: Mercury release and speciation behavior during coal pyrolysis with the addition of calcium chloride in different chlorine contents of 0.1%,0.3% and 0.5% in mass was studied in a temperature-programmed tube furnace. The concentration of gaseous mercury was monitored online with an online mercury analyzer. The results show that the temperature is a key factor for the mercury releasing during coal pyrolysis. With the rising of calcium chloride addition in coal, the percentage of Hg2+ increases, while the temperature of maximum mercury releasing and the release of total mercury decrease. The percentage of Hg2+ also increases to some degrees with the increase of O2 percentage raised. Higher heating rate can promote the mercury release in coal and enhance the proportion of Hg2+ in flue gas. The study indicates that the calcium chloride addition into the low-chlorine coal can enhance the oxidation of Hg0.
Abstract: Drying pretreatment plays an important role in the use of oil shale. Microwave drying is a rapid, efficient and energy-saving method. A microwave drying experiment system was set up by remolding the household microwave oven, by which the microwave drying characters and the influence on the pyrolysis characteristic were investigated. The result shows that the time needed for microwave drying is about 20% of the one for traditional drying, and the rate of microwave drying is much higher than that of traditional drying. The Page model is suitable for describing the process of Liushuhe oil shale microwave drying. There is no difference in the changing curves of the pyrolysis activation energy with conversion for the microwave drying oil shale, hot-air drying oil shale and the original one. The trend of the curve first rises, then falls, and at x≈0.7 appears the maximum value. The activation energy changes between 80 kJ/mol and 200kJ/mol. At the same time, the activation energy of organic matter decomposition for the microwave drying oil shale pyrolysis is increased.
Abstract: The pyrolysis behavior of 7 kinds of typical municipal solid waste (MSW) was investigated by thermogravimetric analysis(TGA). The results show that the starting pyrolysis temperature of kitchen waste is lower than that of any other MSW, which is the most reactive substance among all the typical MSWs. On the contrary, the plastics and the textiles are more difficult to decompose. The Freeman-Carroll method was used for evaluating the activation energy. 20 kinds of mechanism functions of solid-state reaction were applied to the pyrolysis behavior of each component, and then the fitting results were compared to obtain the optimum solution. The optimizing mechanism function and kinetic parameters were used to deduce the kinetic model for 7 components. The data show that the globular symmetry phase boundary reaction mechanism is suitable for the pyrolysis process of PE and wool; 3D diffusion reaction mechanism is suitable for the pyrolysis process of cabbage; and the power law is suitable for the pyrolysis process of cotton and rice.
Abstract: The effect of ultrasonic treatment on the unit structure of pre-and post-hydrotreating asphaltenes were investigated with Shengli vacuum residue and Saudi Arabia light vacuum residue as raw materials. The unit molecular structures of the asphaltenes were analyzed through simulation with the software Chem Bio Draw Ultra version 2012, combining with the data of 1H-NMR, FT-IR and structural parameters of asphaltene units. The results showed that the association number is decreased by ultrasonic treatment, as it can reinforce the ring opening and desorption of alkyl side chain of the asphaltene unit and then exhibits a significant influence on the structure of asphaltene unit after hydrotreating. The model used here can vividly reflect the influence of ultrasonic treatment on the chemical structure of pre-and post-hydrotreating asphaltene unit at molecular level.
Abstract: A series of functionalized acidic ionic liquids (ILs) were synthesized and used to remove non-basic nitrogen (indole) in model oil. The results indicate that the anions have a significant impact on the denitrification efficiency; the denitrification rate of the ionic liquids with various anions increases with their acidity, i.e. it follows the order of HSO4- > CF3COO- > H2PO4- > CH3COO-. The effects of IL/oil ratio, IL/H2O ratio, settlement time, reaction temperature and time on the denitrification efficiency of (CH3CH2)3 N (CH2)3SO3H HSO4 were well considered. The results showed that 99.12% indole nitrogen in the oil can be removed with (CH3CH2)3N(CH2)3SO3HHSO4 under the optimum condition; furthermore, the IL exhibits high stability and its denitrification activity remains almost unchanged even after being reused for six times.
Abstract: The decomposition behavior of phenylalanine, as a model compound of algal protein, in water at high temperature was investigated in a quartz mini-batch reactor. The conversion of phenylalanine at 130~190 ℃ as well as the decomposition pathways and nitrogen transition behavior in the hydrothermal process at 220~340 ℃ with a batch holding time of 5~240 min were determined. The results showed that the conversion of phenylalanine is extremely low at 130~190 ℃, which can be used as the reference temperature for extracting high value-added protein by hydrothermal liquefaction of algae. The major product at 220~280 ℃ is phenylethylamine; however, the yield of styrene is increased with the increase of reaction temperature and holding time. In water at high temperature, phenylethylamine is obtained via decarboxylation of phenylalanine, while styrene is produced via deamination of phenylethylamine under higher temperature and longer holding time; phenylethanol is further formed via the hydration of styrene. Most of nitrogen in phenylalanine is firstly transferred into phenylethylamine via the decarboxylation of phenylalanine, and then further transferred into water-soluble NH4+ via the deamination of phenylethylamine.
Abstract: The thermochemical CO2 splitting activity of NiFe2O4 and NiFe2O4/ZrO2 prepared by the conventional co-precipitation method was investigated with thermogravimetric analysis (TGA) technique. Significant sintering was observed over the two samples during cyclic reactions because of the high reaction temperature. This would lead to an incomplete re-oxidation of the reduced sample in the CO2 splitting reaction. Introduction of ZrO2 could greatly enhance the thermal stability of NiFe2O4, and hence, the cycling behavior in repeated cycles. The catalytic results of NiFe2O4/ZrO2 for cyclic splitting of CO2 in a high-temperature furnace indicate that CO productivity increased with the thermal reduction temperature, while the cycling stability severely decreased with the cyclic number.
Abstract: In this paper, La2O3/γ-Al2O3 catalysts with different La loading were prepared by incipient wetness impregnation method.This paper investigated the influence of La loading and reaction temperature on catalytic performance for the carbon dioxide reforming of DME. The catalysts were characterized by X-ray diffraction (XRD), BET surface area, transmission electron microscopy (TEM), thermogravimetry and differential thermal analysis(TG-DTA). The results showed that the La2O3/γ-Al2O3 with 15% La loading gave the best catalytic performance at 550 ℃.The selectivity of H2 and CO were 93.3% and 76.04%, and the conversion of CO2 and DME were about 85.4% and 100%, respectively, while the selectivity of byproduct CH4 is only 6.3%. This 15% La2O3/γ-Al2O3catalysts had more symmetrical distribution of particle size,larger specific surface area and more proper pore structure, and it kept stable performance during 4 h test. As a result, the catalyst average coking rate was only about 1.387 5 mg/(g·h).
Abstract: The double mesoporous Co-based catalysts were prepared by incipient-wetness impregnation method, which were characterized by the technology of XRD, BET, SEM and H2-TPR. And the influences of reduction temperature on the structure and performance of the catalysts in Fischer-Tropsch were investigated. The result showed that with the increase of reduction temperature, the active sites of catalysts increased, and the activity increased. After the activity reached a certain level, it began to decline. And the methane selectivity increased with the increase of reduction temperature. The related reactive performance might be due to the cobalt oxides on the surface of catalysts formed in the reaction, which made the water gas shift reaction become active, and the hydrocarbon products moved to low hydrocarbons.
Abstract: Non Pt based metals and alloys as electrode materials for methyl alcohol fuel cells have been investigated with an aim of finding high electrocatalytic surface property for the faster electrode reactions. Electrodes were fabricated by electrodeposition on pure Al foil, from an electrolyte of Ni, Co, Fe salts. The optimum condition of electrodeposition were found out by a series of experiments, varying the chemistry of the electrolyte, pH valve, temperature, current and cell potential. Polarization study of the coated Ni-Co or Ni-Co-Fe alloy on pure Al was found to exhibit high exchange current density, indicating an improved electro catalytic surface with faster charge-discharge reactions at anode and cathode and low overvoltage. Electrochemical impedance studies on coated and uncoated surface clearly showed that the polarization resistance and impedance were decreased by Ni-Co or Ni-Co-Fe coating. X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX) and atomic absorption spectroscopy (AAS) studies confirmed the presence of alloying elements and constituents of the alloy. The morphology of the deposits from scanning electron microscope (SEM) images indicated that the electrode surface was a three dimensional space which increased the effective surface area for the electrode reactions to take place.
Abstract: Nano PtPb anode catalyst supported on carbon fiber was prepared by the technology of electro-spinning combined with sintering; the catalyst was characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) and scanning electron microscopy (SEM). The results showed that the nano catalyst is well dispersed on the skeleton of vesicular carbon fiber with a particle size of 3.05 nm; the catalytic efficiency is significantly improved by pre-oxidation at 300 ℃and carbonization at 800 ℃. The catalyst activity in ethanol oxidation was evaluated through cyclic voltammogram (CV) and electrochemical impedance spectroscopy (EIS). The results indicated that the catalyst has better resistance against poisoning; over it, the maximum current density is 125 mA/cm2 and the charge transfer resistance is reduced by 60% in comparison with that over the catalyst carbonized at 700 ℃.
Abstract: The V2O5-WO3/TiO2 catalyst using the mesoporous support of TiO2 made by sol-gel method was prepared with two-step impregnation method and tested for the selective catalytic reduction (SCR) of NO by NH3. The characterization of the catalyst with BET, NH3-TPD, H2-TPR, SEM, activity evaluation and in-situ FT-IR was made to have a deep understanding of the structure, acidity, redox property, catalytic performance, de-NOx activity and the reaction mechanism. The mesoporous TiO2 has a surface area of 158.6 m2/g, and the prepared de-NOx catalyst has a slightly decreased surface area of 136.7 m2/g. The V2O5-WO3/TiO2 catalyst enables the NO conversions to reach to about 80% at 250~400 ℃ and φNH3/φNO = 0.8, showing the feature of wide working-temperature for the catalyst. The surface adsorption of reactants characterized by in-situ FT-IR shows that NH3 is adsorbed on both the Lewis and Brnsted acidic sites to generate a few different transformation species. The transformation from NH3 to NH2 is the rate-determining step for de-NOx reaction in NH3-SCR. It is found that the NH3-SCR reaction occurs between the adsorbed NH3 and gaseous NO, which follows the Eley-Rideal reaction mechanism.
Abstract: The influences of temperature, sulfur dioxide concentration and space velocity on the regeneration behavior of modified semi-coke supported Fe/Zn/Ce sorbent were investigated in a quartz fixed-bed reactor of 20 mm diameter. The sorbents were prepared by co-precipitation method with the Zn/Fe/Ce molar ratio of 1.0:2.0:0.6 supported on the modified semi-coke. The changes of crystalline phase and morphology of the sorbent before and after regeneration were examined by X-ray diffraction and scanning electron microscopy. The surface area and pore volume of sorbents were characterized by N2 adsorption. The results show that the sorbent can be regenerated over 600 ℃ and the elemental sulfur is produced. The optimum regeneration temperature, SO2 concentration and space velocity are 700 ℃, 12% and 5 000 h-1, respectively.
Abstract: Resin-based spherical activated carbons were prepared from four kinds of ion exchange resin(two strong basic resins D201 and D280, two weak basic resins D301G and D301R)through sulfonation, carbonization and activation treatment. The yield of the spherical activated carbons, the surface morphology and the specific surface area were characterized by thermogravimetric analysis, scanning electron microscopy and nitrogen adsorption. The adsorptive capacities of the spherical activated carbons towards CO2 were investigated. The results showed that the yield of carbonized spheres was improved after sulfonation. The four prepared spherical activated carbon samples exhibited good adsorption performance to CO2. The strong basic resin-based spherical activated carbons provided a higher CO2 adsorption capacity than the weak basic resin-based spherical activated carbons. The CO2 adsorption capacity of the spherical activated carbons obtained from strong basic resin D201 reached 2.57 mmol/g, and remained high after ten cycles.
Abstract: The Fe2O3/Al2O3 oxygen carrier decorated with 10% Cu was prepared by freezing granulation method; its reactivity and stability for chemical looping combustion was investigated in a thermogravimetric analyzer by alternately exposing the oxygen carrier to reducing and oxidizing conditions to simulate the chemical looping combustion (CLC) process. The results indicated that the Cu-decorated Fe2O3/Al2O3 oxygen carrier exhibits a good stability during the isothermal redox cycles at 850 and 900 ℃. Although the oxygen carrier is sintered slightly at the beginning of redox cycles at 950 ℃, it is stable in the later cycles. With the increase of the reaction temperature, the oxidation rate of the oxygen carrier increases monotonously, while the oxygen transport capacity and reduction rate decrease first and then increase along with the temperature. Compared with the non-decorated Fe2O3/Al2O3 oxygen carrier, the Cu-decorated Fe2O3/Al2O3 oxygen carrier exhibits higher oxygen transport capacity and reduction rate, but lower oxidation rate at 900 ℃; both of them has a good stability during the redox cycles.
Supervisor：Chinese Academy of Sciences
Sponsors by：Shanxi Institute of Coal Chemistry, Chinese Academy of Sciences Chinese Chemical Society
