Abstract: An experimental procedure was tested for studying the sintering and fusion characteristics of fly ash from anthracite fluidized bed gasification at the temperature approaching the ash deformation temperature (DT), and the slagging characteristic was investigated. The quantitative analysis on the composition of crystalline mineral matter and the amorphous phases in the thermal treated ash was carried out using X-ray diffraction analysis (XRD). Experimental results show that the slagging tendency of fly ash is related to the transformation of minerals. AFTs of fly ash are lower than those of original coal due to higher contents of Fe, Ca, and Mg. The formation of melting matrix causes a liquid-phase sintering at 100~200℃ below the DT, which leads to a shrinkage deformation and clinkering due to the formation and transformation of feldspar that plays a 'glue’ role in sintering. A great amount of Ca and all of Fe are found in the glass phase, which improves the amorphous phase in concentration. These fluxing components in the glass phase that do not crystalize during thermal treatment can promote the densification process of sintering and the slagging or agglomeration tendencies.
Abstract: The catalysis of potassium carbonate on the steam gasification of coals was investigated in a fixed-bed reactor. The interaction of potassium with mineral matter in ten coals was examined. The gasification residue after leaching with water was analysed by X-ray diffraction (XRD) and X-ray fluorescence (XRF). The results show that potassium aluminum silicate is the major crystallite derived from the interaction of potassium with mineral matter. As the ash is in low calcium content, the molar ratio of non-recoverable potassium to aluminum is one. However, as the ash is in high calcium content, the calcium can fix a large number of aluminum in the form of gehlenite (Ca2Al2SiO7), which would inhibit the deactivation of potassium.
Abstract: A comprehensive knowledge of the release characteristics of inorganic compounds is required by the designing of gas scrubbing and hot gas cleaning technology. The principal objective of this work was to examine the influence of pressure on the release of nitrogen during pressurized coal gasification in a pilot-scale pressurized ash agglomerating fluidized bed facility with 800 mm i.d.. Jincheng anthracite was gasified at gage pressures of 0.6, 1.0, 1.5 and 2.0 MPa with steam/O2 (3/1, volume ratio) at 1 000℃. The analysis of nitrogen content and form in hot gas and solid by-product was carried out. The quantitative analysis results show that most of nitrogen is transferred into gas phase, which is slightly changed after 1.0 MPa coupled with an enrichment of nitrogen in solid phase with the increase in pressure. The discussion on the mechanism of nitrogen release at pressure was carried out by contrast analysis of nitrogen form in the coal and bottom ash at microcosmic level.
Abstract: A series of grafted sulfonated lignin-based dispersants, GCL3J series with different molecular weight, were prepared by graft copolymerization, sulfonation and polycondensation reactions using alkali lignin as the main raw material. The effects of molecular weight of GCL3J on its adsorption behaviors and dispersion properties in coal water slurry were investigated. Rheological property investigations show that GCL3J series are better than FDN in reducing the viscosities of coal water slurry, especially for GCL3J-3 which Mw and inherent viscosity are 31 500 Da and 8.06 mL/g, respectively. Adsorption results show that all the adsorption isotherms of GCL3J on coal surface are belonging to Langmuir monolayer adsorption. With the increase of molecular weight, the adsorption amounts on coal surface decrease. Zeta potential results show that the adsorption forces between GCL3J and coal surface increase with the increase of molecular weight.
Abstract: For the poor fluidity of coal tar generated from circulating fluidized bed polygeneration system, a series of research was carried out to decrease the viscosity. Through the analysis of X-ray diffraction, the possibility that the wax crystal increases the viscosity at room temperature was excluded. The viscosity and contents between coal tar and coal tar pitch were compared, and the impact of quinoline insoluble on the softening point was also investigated. The results reveal that it is reasonable to employ the distillates to decrease the viscosity of coal tar. Four kinds of distillates were blended in the coal tar to improve the fluidity, and the composition of the distillates was gotten through the GC-MS analysis. It is concluded that the molecule which contains both hydrophilic groups and hydrophobic groups possesses a great effect on the viscosity reduction, and the more the amount, the better the viscosity reduction. Four kinds of mono-component additives were tested, and the theory was verified. For the viscosity reduction, the molecule with both groups is better than that with only hydrophobic groups.
Abstract: The combustion reaction mechanism and kinetic characteristics of pulverized anthracite coal in two phase flow were studied by micro fluidized bed kinetic analyzer, and compared with those by thermogravimetry method. The results show that the combustion reaction mechanism of pulverized coal and the composition of combustion gas product change when the temperature exceeds 850℃. When the flow rate exceeds 0.10 m/s, the effect of gas diffusion is eliminated basically, and the combustion reaction rate of pulverized coal is mainly controlled by the interface reaction. The combustion reaction rate of pulverized coal increases in a power function form with oxygen partial pressure, and the influence of oxygen partial pressure on the static combustion is more remarkable. The apparent activation energy of pulverized coal combustion in two phase flow decreases by 49 kJ/mol compared with that of static combustion, and the interfacial chemical reaction resistance of pulverized coal combustion in two phase flow is also much smaller than the results by thermogravimetry method at the same temperature.
Abstract: To investigate the changes in the structure of petroleum coke and coal after rapid pyrolysis under the condition similar to the practical coal gasifier, two kinds of petroleum cokes and one bituminous coal were pyrolyzed in a drop tube furnace at 800~1 400℃. The structure of petroleum coke and coal were characterized by using surface area porosity analyzer and XRD (X-ray diffraction) analyzer, the CO2 gasification reactivity of samples was examined by TGA (thermogravimetric analyzer). The result shows that the pore in petroleum coke is mainly micropore compared with coal; with the increase of pyrolysis temperature, the micropore surface area of petroleum coke and coal increases first and then decreases gradually. Rapid pyrolysis lowers the graphitization degree of petroleum coke and coal. The changes in the carbon crystallite structure for petroleum coke are mainly observed in the average stacking height, while the changes in the carbon crystallite structure for coal is manifested in the value of 2θ002, interlayer spacing and average stacking height. Although the gasification reactivity changing tendency of petroleum coke and coal with the increase of pyrolysis temperature is different, the gasification reactivity is closely related to the carbon crystallite structure.
Abstract: Vacuum residue from Saudi Arabia light crude oil (ALVR) was thermally reacted at 395℃ under the atmosphere of nitrogen. Thermal reaction samples were obtained by online sampling device at different reaction times, and the asphaltene aggregate size was determined by small-angle X-ray scattering (SAXS) measurements. The aggregate size of asphaltene decreases from 29~21 nm in the initial stage of coke induction period; during later stage of coke induction period, the asphaltene aggregate size increases rapidly and reaches to 43 nm when thermal reaction time reaches to 150 min. After the stage of coke induction period, the asphaltene aggregate size changes little and is in the range of 46~42 nm. In the thermal reaction process of residue, the aggregate size of asphaltene is jointly affected by the thermal cracking and association-disassociation of asphaltene, but does not show obvious relationship with asphaltene content.
Abstract: The concentrations and modes of occurrence of U and Th in 23 oil shale samples from China were studied. The concentrations of U and Th were determined by inductively coupled plasma-mass spectrometry. The occurrence of U and Th in Huadian and Luozigou oil shale was investigated using six-step sequential chemical extract method. The concentrations of U in oil shale are within 10×10-6 and average of 3.92×10-6. The concentrations of Th in oil shale are within 20×10-6 and average of 10.51×10-6. The abundances of U and Th in oil shale are slightly higher than in crust and close to sedimentary rocks. The experimental results of floating and sinking roughly equal that of the sequential chemical extraction in U and Th. The U and Th in oil shale are mainly existed in minerals.
Abstract: Cornstalk cellulose was liquefied in sub- and supercritical ethanol using an autoclave at 320℃ for 60 min. Effects of ethanol dosages on ketones formation from cellulose liquefaction were investigated. The yield of ketones was 1.25% in the absence of ethanol and then increased to 18.38% while adding 160 mL ethanol. Ethanol favored the formation of ketones from cellulose liquefaction. The liquid products at different ethanol dosages were analyzed by FT-IR and GC/MS. The results were shown as follows: (1) Cellulose was converted to active cellulose which was transformed into aliphatic ketones such as 4-hydroxy-4-methyl-2-pentanone by dehydration, decomposition, ring-opening reactions, isomerization and aldol condensation. (2) The alicyclic ketones (cyclopentenone) was formed by the cleavage of C-O-C and C-C bonds of the active cellulose under the effects of ethanol free radicals. Aromatic ketones (2-(formyloxy)-1-phenyl ethanone) were generated by cyclopentenone reaction with intermediates. (3) Aromatic ketones were decomposed to carboxylic acids and small molecule ketones under ethanol free radicals. According to the above results, the reaction network of ketones formed from cellulose in sub- and supercritical ethanol was proposed.
Abstract: An experimental study on co-pyrolysis of biomass and Pingshuo coal was performed using temperature programmed thermogravimetric analysis under atmospheric pressure in high purity nitrogen (99.999%). Sawdust and rice straw were chosen as biomass feedstocks. The final pyrolysis temperature was designed as 1 273 K and the heating rate was 10 K/min, and the mixture ratios of the biomass were 20%, 50% and 70% respectively. The results indicate that the initial temperature of volatile emission from Pingshuo coal and the temperature corresponding to the maximum pyrolysis conversion during co-pyrolysis vary with the ratio of biomass. Moreover, in co-pyrolysis there is difference between the experimental and calculated DTG curves. In addition, the method of Coats-Redfern was used to calculate the activation energy and frequency factor of pyrolysis for the coal and biomass. The results show that the activation energy and frequency factor change with the mixing ratio of the biomass, and it can be deduced that there exist the synergetic effects between the biomass and Pingshuo coal during their co-pyrolysis process.
Abstract: The straw pyrolysis chars obtained at 873, 1 073 and 1 273 K were investigated with SEM, BET and TGA to conduct the characterization. The reduction of NO by different straw chars was investigated, with considering the effects of char concentration cchar and NO concentration cNO, to analyze the effect of pyrolysis temperature on the chemical physical characteristics of biomass char. The results show that straw char obtained at 1 073 K holds the most developed pore structure and surface area, the best combustion activity, and the highest NO reduction rate. As the char concentration increases, NO reduction rate linearly increases. As the NO concentration increases, NO reduction rate decreases as a power-function relation. At the transition temperature about 1 173 K the char-NO reaction changes from dynamic-control region to diffusion-control region. In the dynamic-control region, the pyrolysis temperature affects the activation of the char-NO reaction inconspicuously. The reaction orders for NO and straw char are found to be 0.89 and 1.00, respectively.
Abstract: The hydrogenation of di-furfural-acetone for producing long-chain alkane precursors was carried out over Raney Ni catalyst; the effects of reaction temperature, pressure and time on the product distribution were investigated. The results indicated that Raney Ni exhibits excellent catalytic performance at low temperature. The hydrogenation can be enhanced by increasing temperature and pressure; at 50℃, 2.5 MPa and after 2 h reaction, the di-furfural-acetone is completely converted with 80.8% of the selectivity to the saturated hydrogenated products. However, excessive high temperature may be harmful to the hydrogenation. It was found that the hydrogenation activity towards three double bonds in di-furfural-acetone follows the order of ethylenic bond > furan ring double bond > C=O. Various solvents (water, methanol, tetrahydrofuran and cyclohexane) are also different in their effects on the catalytic performance; Raney Ni exhibits much higher hydrogenation activity in methanol than in other solvents.
Abstract: Basic ionic liquid N-methyl-N-butyl morpholine hydroxide ([Nbmm]OH) was synthesized by two-step methods with N-methyl morpholine, N-butane bromide and potassium hydroxide as the materials. The chemical structure and thermal stability of the basic ionic liquid [Nbmm]OH were characterized by FT-IR, elemental analysis and TGA; its solubility and catalytic performance in the esterification of oleic acid with methanol were investigated. The results showed that the basic ionic liquid has a good thermal stability; it is stable at a temperature above 200℃. The ionic liquid [Nbmm]OH is soluble in the solvent of strong polarity and the solution in water exhibits strong alkalinity. The basic ionic liquid performs well as a catalyst in the synthesis of methyl oleate from oleic acid and methanol; with a molar ratio of oleic acid to methanol of 1:6 and the amount of catalysts of 15%, the conversion of oleic acid reaches 93.9% after reaction under 60℃ for 10 h. Moreover, the basic ionic liquid synthesized in this work is potential for application in industry, due to its easy recyclability from the reaction system as well as the green and reusable nature.
Abstract: In this work, fullerene was modified by platinum, ruthenium, tin and tungsten nanoparticles. The material was characterized by XRD, ICP-OES and TEM micrograph. The average nanoparticle size on fullerene was 5~8 nm. The application of this material was investigated as a catalyst for methanol oxidation in direct methanol fuel cell. A glassy carbon electrode was modified by Pt/Ru/Sn/W fullerene and electrocatalytic activity of the electrode toward methanol oxidation in basic medium has been demonstrated and investigated using cyclic voltammetry. The catalyst showed good reactivity for methanol oxidation.
Abstract: Ni/SiO2 catalysts were prepared by impregnation method and treated by glow discharge plasma. The Ni/SiO2 catalysts were characterized by CO2-TPD and H2-TPR; the effects of plasma treatment on the performances of Ni/SiO2 in adsorption, reduction, and catalytic methanation of CO2 were investigated. The results showed that the plasma treatment can remarkably improve the dispersion of active components and enhance the reactivity of Ni/SiO2 catalyst. The catalytic performance of Ni/SiO2 in CO2 methanation is also enhanced by the plasma treatment; the conversion of CO2 and the space time yield of CH4 over the plasma modified catalyst are higher than those over the Ni/SiO2 catalyst obtained through conventional impregnation and calcination method.
Abstract: Alkali and acid modified HZSM-5 molecular sieves were prepared through treating with different alkali solutions together with nitric acid of different concentrations; four catalysts, i.e. H(0.2)-Na-ZSM-5, H(0.5)-Na-ZSM-5, H(0.2)-K-ZSM-5 and H(0.5)-K-ZSM-5 were obtained. These catalysts were characterized by means of XRD, NH3-TPD, ICP, FT-IR and Py-IR; their performance in the synthesis of durene from methanol was investigated in a fixed-bed down-flow reactor. The results showed that the highest selectivity to durene for methanol aromatization is achieved over the H(0.2)-K-ZSM-5 catalyst, which should be ascribed to its large pore size and abundant weak B acid sites arising from the alkali and acid modification.
Abstract: Effects of H2O on the catalyst Cu+/S2O82-/γ-Al2O3 of DMC synthesis in slurry reactor were investigated under the conditions of 120℃ and 3.0 MPa. The results showed that the introduction of water into reaction system led to quick catalyst deactivation. The catalysts were characterized by the Elemental Analysis, XRD, DTG, Py-FT-IR and NH3-TPD. The results showed that active component Cu and CuCl, loading on the surface of S2O82-/γ-Al2O3 support, reacted with O2 and H2O, then formed Cu2(OH)3Cl which was essentially inactive for oxidative carbonylation of methanol to dimethyl carbonate. The catalyst deactivation rate speeded up with increasing water injection.
Abstract: The catalytic performance of CuO/ZnO/CeO2/ZrO2 prepared by co-precipitation for methanol steam reforming was investigated using a statistical set of experiments in order to optimize the reaction conditions for obtaining minimal carbon monoxide in the reformed gas. The reaction temperature, steam to methanol ratio, methanol gas hourly space velocity (GHSV) were evaluated with a full factorial design experiment. The reaction temperature displayed much greater influence on the response (methanol conversion and CO concentration in reformed gas), GHSV has minimal influence on the CO concentration in reformed gas. At a fixed low methanol GHSV (300 h-1), a central composite rotatable design was then used to approximate the optimal conditions by simultaneously considering the methanol conversion and CO concentration. The optimum theoretical conditions were found to lie within a reaction temperature of 249~258℃ and a W/M ratio of 1.76~2.00, in close agreement with the experimental results.
Abstract: Three Mn-based catalysts of Mn/Ce-ZrO2, Mn/P25, and Mn/Al2O3 with different supports were prepared by impregnation method and were used in the selective catalytic reduction of NO with NH3 (NH3-SCR) at low temperature. The catalysts were characterized by XRD, NH3-TPD and H2-TPR and their activity at low temperature as well as the resistances towards H2O and SO2 were investigated. The results showed that Mn/Ce-ZrO2 exhibits better activity at low temperature (100~160℃) than other two catalysts, while Mn/P25 performs better at high temperature (160~220℃), which is related with the redox characteristics of the catalysts. Mn/Ce-ZrO2 is more easily to be reduced at low temperature while Mn/P25 has a larger reduction peak at higher temperature, as revealed by H2-TPR. All of the three catalysts have a good resistance to H2O; among them Mn/Ce-ZrO2 exhibits the best resistance to SO2 and H2O, which should be attributed to the abundant acid sites and the instability of ammonia sulfate formed on the surface of Mn/Ce-ZrO2.
Supervisor：Chinese Academy of Sciences
Sponsors by：Shanxi Institute of Coal Chemistry, Chinese Academy of Sciences Chinese Chemical Society
