Abstract: Zhundong subbituminous coal was exhaustively extracted with isometric carbon disulfide (CDS) and acetone mixed solvent. The extract was fractionated with petroleum ether (PE) and CDS into PE-extractable portion (E1) and CDS-extractable portion (E2). E2 was sequentially eluted with PE and 30% CDS/PE mixed solvent through a silica gel-packed column. A series of long-chain normal alkanals (LCNAs, C18~27) were enriched from E2 and identified with a gas chromatography/mass spectrometer. The fractional extraction and subsequent column chromatography provide an effective approach for enriching LCNAs from middle-and low-rank coals. LCNAs could be a class of important biomarkers.
Abstract: The electro-hydrogenation of coal on Pb electrode in a mixed dimethylformamide-ethanol (DMF-EtOH) electrolyte was investigated. The hydrogenation product was in-situ extracted from the organic solvent and characterized. The electrolysis products show a significant increase in H/C ratio, indicating increased hydrogenation efficiency. IR spectroscopy shows the reduction of C=O bond and aromatic ring, as well as the cleavage of bridge bonds, such as C-O-C, are the main reactions during the electrolysis. This is also confirmed by the increase of γ-H content measured by 1H-NMR.
Abstract: Raman spectroscopy was applied to investigate the temperature dependent pyrolysis of Australian bituminous coal from 298 to 1 473 K in argon and nitrogen atmospheres. The results indicated that the pyrolysis of Australian bituminous coal can be divided into three stages: 298~873 K, precipitation and volatilization of small molecule compounds (original in coal or decomposed by heat treatment); 873~1 273 K, cracking and volatilization of macromolecular compounds; 1 273~1 473 K, graphitization of coke. After annealing at 1 473 K, the ordered carbon content of coke is significantly related to the atmosphere of nitrogen or argon; nitrogen is conducive to the pyrolysis of coal. Annealing or holding time exhibits little effect on coal pyrolysis and coke structure evolution; however, long holding time is helpful for the volatilization of small molecules at low temperature.
Abstract: By analyzing the organic sulfur content in the model compounds and the Xinyu refined coking coal, the curve fitting methods and setting parameters of XPS spectra were discussed. The results indicate that when analyzing the content of different sulfur forms in coal with XPS, the curve fitting methods of 2p3/2 and 2p1/2 splitting peaks and some other parameters are set as follows: an approximate 2:1 relative area separated by 1.18 eV with equal L-G% and FWHM level. In addition, the 2p3/2 peak of each organic sulfur is fixed as: mercaptan/thioether 162.1~163.6 eV, thiophene 164.0~164.4 eV, and sulfoxide 165.0~166.0 eV. Good reproducibility and fitting level are achieved when the curve fitting parameters are adjusted finely and dynamically within a certain range.
Abstract: An Mengdong lignite was modified by hydrothermal method. The water binding energy between the coal surface skeleton molecules and various oxygen containing functional groups was determined and analyzed by means of micro calorimeter. The results show that carboxyl and carbonyl significantly reduced with the increase of temperature, while the change of hydroxyl is complex. The order of hydrophilic ability from large to small for oxygen containing functional groups on coal surface is carboxyl, phenolic hydroxyl, carbonyl, large molecular of the coal.
Abstract: The gasification tests of Shenmu coal char were carried out in a pressured fixed bed reactor to investigate the effect of gasification agents (H2O, CO2, H2), catalyst loading, and partial pressure of hydrogen and carbon monoxide on the carbon conversion and reaction rate. The results show that the heterogeneous reaction rate is in the order of C-H2O >C-CO2>C-H2. H2 and CO inhibit the steam gasification rate to some degrees. The inhibition of CO is much greater than that of H2. The carbon conversion decreases by about 50% with the addition of only 5% CO at 700 ℃. A kinetic model is developed combined Langmuir-Hinshelwood (L-H) with the random pore model, considering the effect of catalyst loading and the partial pressure of gasification product gases. The deviation between predication and experiment value is less than 10%, indicating that the derived kinetic model is appropriate for describing the catalytic coal gasification with steam.
Abstract: On the test rig of oxygen-enriched gasification in circulating fluidized bed, the effects of oxygen concentration and equivalent ratio on gas components, gas production rate, cold gas efficiency and carbon conversion are investigated, when the gasification temperature is kept at 910 ℃ by adjusting steam flow. The results show that when oxygen concentration increases from 25% to 40%, N2 reduces from 48.82% to 33.83%, H2 increases from 21.47% to 27.59%, and CH4 changes little. Due to the influence of steam flow, CO decreases and CO2 increases when oxygen concentration is higher than 35%. Heat value of the gas with the oxygen concentration of 40% is 1.84 times of that with air gasification. Gas production rate decreases from 2.35 m3/kg to 2.13 m3/kg, and both of cold gas efficiency and carbon conversion increase with the increase in oxygen concentration. As equivalent ratio changes from 0.20 to 0.29, N2 reduces and then increases, H2 grows from 24.01% to 25.46% and then remains unchanged, CO and CH4 keeps reducing, CO2 keeps increasing, and gas production rate increases from 1.94 m3/kg to 2.29 m3/kg. Influenced by both stem flow and equivalent ratio, cold gas efficiency increases firstly and then decreases, and carbon conversion keeps increasing.
Abstract: The carbon skeleton structure of oil shales from Gansu Yaojie mine was characterized by the 13C solid-state NMR; the chemical structure parameters of cluster in the oil shales, such as average number of carbons, aromatic carbons, aliphatic carbons and aromatic rings, were determined. TG-FTIR tests were used to obtain the yields of pyrolysis products. Considering the cluster chemical structure parameters determined by 13C solid-state NMR, the release of pyrolysis products was simulated by FLASHCHAIN. The simulation results are in good agreement with the TG-FTIR tests, proving the rationality of the model proposed.
Abstract: The calcium aluminate cement as a cheap material was used to produce a novel cement-supported Fe2O3 oxygen carrier via mechanically mixing and extrusion method. The ratio of cement addition and the effect of K as additive on the CLC performance of coal were experimentally investigated in a single fluidized bed reactor. The results suggest that there is a stable product of Ca2Al2SiO7 formed in the oxygen carriers. The coal gasification rate and conversion rate are significantly accelerated by K in the oxygen carrier samples. A stable phase of K2Fe22O34 is found in the oxygen carriers. The catalytic effect of K in the coal CLC process depends on the phase transformation of K2Fe22O34 and KFeO2.
Abstract: The sequential chemical extraction (three steps) was used to examine the modes of occurrence of alkali metals in four kinds of Xinjiang coals based on the solubility in distilled water, ammonium acetate and hydrochloric acid. The water-soluble anions were analysed by ion chromatography. The contents of alkali metals in the coal ash made at different temperatures and residence times were measured respectively, and the release forms of alkali metals from coal ash were also simulated by Factsage. Results show that the most of sodium in coal is the water-soluble one and the potassium only exists in the insoluble form. Water-soluble alkali metals may exist in the form of hydrated ion of chloride. The release of alkali metals from coal is the fastest during 400~600 ℃,which are mostly water-soluble alkali metals; and the release of alkali metals mostly occurs at the later stage of combustion. Alkali metals in ash would react with the components of flue gas at high temperature, which produces chloride and hydroxide. It can be inferred that the sodium makes a great contribution to the formation of low temperature eutectoid at 700 ℃.
Abstract: Particulate matter from coal combustion is one of the most main atmospheric pollutants in urban China currently. It has caused serious damage to the environment and human health. A 3012H type automatic smoke-dust(flue-gas) monitor was used to collect PMs in front of the ESP of 1# boiler in Shajiao C power plant in Humen. The influence of boiler load and coal type on the emission characteristics of the fly ash was studied. The particle size distribution, chemical composition, mineral constituent and morphology characteristics of the fly ash were also analyzed. The results indicate that the fractions of PM1 and PM2.5 increase with the rising of boiler load, however, the concentration of the total smoke-dust decreases. The level of PM1 and PM2.5 becomes higher when the blending ratio of Yitai coal increases. The coal is easy to form coal cells containing molten spherules when burned in a high load boiler, and to form porous cenospheres when burned in a low load boiler. The mineral component of the ashes collected from different situations is similar.
Abstract: The isothermal gasification tests of 4 biomass samples were performed in CO2 atmosphere using a thermo-gravimetric analyzer at 750~1 000 ℃. The results show that the gasification reaction rate increases with increasing gasification temperature. Through the dimensionless procedure of r using r0.2, two different trends of dimensionless gasification reaction rate with carbon conversion are observed when the gasification temperature is changed. Accordingly, activation energies of the biomass chars were calculated by iso-conversion method. It is found that the activation energy of any biomass char is basically constant, not varying with the carbon conversion obviously. Activation energies of different chars are mainly affected by the inorganic mineral composition in the char and can be described in a linear function of the ratio of WC/WFC, which is E=233.9-1 005.7×(WC/WFC). It can be predicted that the intrinsic activation energy of the biomass char might tend to a certain value 234 kJ/mol if the catalytic effect of the metallic element is ignored.
Abstract: The co-gasification of rice straw with PVC was carried out in a fixed bed reactor; the transformation of K, Na and Cl elements was investigated through X-ray diffraction (XRD) and thermodynamic calculation. The results indicated that the release of chlorine is related to the operation temperature and PVC proportion in the co-gasification of rice straw and PVC. The content of PVC in the blend plays an important role in the release of Cl, especially at 800~900 ℃; the amount of Cl released in gasification of the blend with 20% PVC (11.5% Cl) is increased by 16.5%, compared with that of pure rice straw at 900 ℃. Meanwhile, the increase of Cl content in the blend also prompts the release of K and Na. When the fraction of PVC is higher than 20% (> 11.5% Cl), the presence of Cl can restrain the release of K and Na at 850 ℃, which are retained in the ash as KCl and NaCl during the co-gasification of rice straw and PVC at 850 ℃; the content of which decreased with the increase of PVC countent in the blend.
Abstract: Supercritical water oxidation (SCWO) experiments of typical alcohols such as methanol, ethanol, isopropanol were carried out by using an innovatively designed lab scale, continuous flow gas sealed wall reactor (GSWR) to explore the reaction pathways and generalities of simple alcohols. The investigation indicates that during the supercritical water oxidation reactions, methanol has a lower conversion than ethanol and isopropanol, and with the main intermediate of formaldehyde. However, the important intermediates for SCWO of ethanol and isopropanol include acetone, acetic acid, acetaldehyde and methanol. Dehydrogenation, decomposition and polymerization reactions associated with many free radicals are involved in the supercritical water oxidation processes of all three alcohols, and three kinds of products produced, which include chemicals with the increased, unaltered and decreased carbon chain compared with the reactants, but generally speaking, the tendency of decreased carbon chain orientation dominates for the SCWO reactions of alcohols, and has the terminal products of carbon dioxide and water.
Abstract: The catalytic conversion of methanol to dimethylether (DME) was studied over CuO/Al2O3, ZnO/Al2O3 and ZnO-CuO/Al2O3 nanocatalysts prepared in presence or absence of ultrasonic irradiation. The catalysts were characterized by X-ray diffraction (XRD), surface characterization method (BET), scanning electron microscope (SEM), H2-temperature programmed reduction (H2-TPR) and temperature programmed desorption of ammonia (NH3-TPD). The experimental results show that during catalytic dehydration of methanol to dimethylether, the activities of the CuO/Al2O3, ZnO/Al2O3 and ZnO-CuO/Al2O3 catalysts prepared using ultrasonic treatment are much higher than those prepared in absence of ultrasonication. SEM shows that the use of ultrasonication results in much smaller nanoparticles. BET and XRD show that the ultrasonication increases the surface area and pore volume of the catalysts. H2-TPR profiles indicated that reducibility of the sonicated nanocatalysts is carried out at lower temperatures. NH3-TPD shows that ultrasound irradiation has enhanced the acidity of the nanocatalyst and hence enhanced catalytic performance for DME formation.
Abstract: ZnO, ZnAl2O4 and Zn/Al mixed oxide catalysts were prepared by thermal decomposition of hydrotalcite-like layered precursors derived from urea precipitation at 1 073 K. Both ZnAl2O4 and ZnO phases were observed in ZAO-3 catalyst at 1 073 K from XRD patterns. The NH3-TPD and CO2-TPD results revealed that the acidity and basicity of Zn/Al mixed oxide catalysts changed with the introduction of Al. Combined with the in-situ FT-IR results of dimethyl carbonate (DMC) decomposition over ZAO-3(1 073 K), ZnAl2O4, ZnO at various temperatures, it was found that the synergistic effect between acidic and basic sites over ZAO-3(1 073 K) could stabilize DMC molecules and inhibit the decomposition of DMC.
Abstract: The effects of the support on active site formation and hydrodenitrogenation(HDN) activity of nickel phosphide catalysts were examined, using TiO2, Al2O3 and TiO2-Al2O3, composite supports. A series of TiO2-Al2O3 prepared by hydrolysis and deposition of tetrabutyl titanate on macropore Al2O3, and the supported nickel phosphide catalyst, were prepared by incipient wetness impregnation and in situ H2 reduction method. The samples were characterized by X-ray diffraction(XRD), BET surface area, transmission electron microscopy(TEM) and H2 temperature-programmed reduction(H2-TPR).Their hydrodenitrogenation(HDN) performance were evaluated on a continuous-flow fixed-bed reactor by using quinoline as the model molecules. The results showed that the TiO2-Al2O3 composite support still retained the pore properties of macropore Al2O3, and TiO2 were well dispersed on the Al2O3 surface in the form of anatase. Different supports have great influence on the reduction behaviour of the oxidic precusors and HDN activity of phosphide catalysts. The main active phase after reduction was Ni2P phase for the TiO2 and TiO2-Al2O3 supportd catalyst, but only Ni12P5 appeared for the Al2O3 supported catalyst. The order of HDN activities of nickel phosphide reduced at optimal reaction conditions was TiO2-Al2O3 > Al2O3> TiO2. TiO2-Al2O3 supported catalyst with the Ti /Al atomic ratio of 1:8 exhibited the highest HDN activity among all catalysts. The presence of TiO2 weakened the strong interaction between the Al2O3 and phosphate, and contributed to the formation of Ni2P active phase and the improvement of HDN activity.
Abstract: The influence of calcination temperature on the catalytic activity of Mn-based catalysts impregnated on TiO2 for the oxidation of NO was studied. The results showed that, relatively low calcination temperature was beneficial to promote the catalytic activity of Mn/TiO2 catalysts. The catalysts were characterized by various techniques to study the influence mechanism of calcination temperature, including X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), H2 temperature programmed reduction (H2-TPR) and O2 temperature programmed desorption (O2-TPD). It could be concluded that Mn2O3 played a dominant role in the process of NO oxidation, and the relatively lower calcination temperature could enhance the percentage of Mn2O3 in MnOx, as well as promote the dispersion of MnOx on TiO2, thus raising the catalytic activity of Mn/TiO2. When the calcination temperature was higher than 500 ℃, the agglomeration began to appear, and the crystalline phase of TiO2 was transformed from anatase to rutile, Mn2O3 was, as well, transformed from amorphous phase to crystalline phase. The test results of H2-TPR and O2-TPD showed that relatively lower calcination temperature was beneficial to the reduction ability of Mn/TiO2 catalysts and the desorption of chemisorbed O2- on catalysts surface, the interaction of the two factors resulted in good mobility of chemisorbed O2- on catalysts surface, which was good for the activity of catalysts.
Abstract: The effect of SO2 on the reduction of NO by methane over iron and iron oxides was investigated at 300~1 100 ℃ in an electrically heated ceramic tubular flow reactor in simulated flue gas and N2 atmosphere. The iron catalyst after reaction was characterized by X-ray diffraction (XRD) and the mechanism of NO reduction by methane over iron catalyst in the presence of SO2 was elucidated. The results demonstrated that methane is effective to reduce NO over iron and iron oxides and SO2 in the flue gas has little influence on the reduction of NO. In N2 atmosphere with 0.01%~0.04% SO2, metallic iron can simultaneously eliminate almost 100% of NO and SO2 at a temperature above 700 ℃. In the simulated flue gas with 0.01%~0.04% SO2, the efficiencies of NO reduction at 850 ℃ and 950 ℃ are higher than 95% and 98%, respectively; the influence of SO2 on NO reduction is insignificant. More than 95% of NO is reduced by 1.13% methane over iron at 1 000 ℃ in a durable test over 100 h in the simulated flue gas atmosphere containing 0.02% SO2.
Supervisor：Chinese Academy of Sciences
Sponsors by：Shanxi Institute of Coal Chemistry, Chinese Academy of Sciences Chinese Chemical Society
