Abstract: Xianfeng lignite (XF) was used as raw material to investigate its structural evolution during hydrothermal treatment in a 500 mL autoclave.The structure was characterized by solid state 13C nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FT-IR).The results show that the carbon contents increase and oxygen contents decrease after hydrotnermal treatment.The weak bonds in lignite are broken and the oxygen functional groups decrease gradually during hydrothermal treatment below 240℃.Hydrogen is donated from water to lignite through ionic pathway and transferred into lignite.The methyl carbon increases at 200℃ and then decreases.The methenyl carbon increases from 4.80% in XF to 13.16% in XF-240.The released gas is mainly CO2 during hydrothermal treatment.The hydrocarbon composition in released gas increases with the treated temperature.The covalent bonds are broken above 240℃.The hydrocarbon composition in released gas increases from 2.13% at 240℃ to 8.59% at 300℃.The aliphatic carbon in lignite deceases from 44.83% in XF-240 to 39.49% in XF-300.The oxygen-linked carbon in lignite decreases from 12.57% in XF-240 to 1.49% in XF-300.Hydrothermal treatment plays a role in deoxygenation and upgrading of raw lignite.The oxygen contents decrease by about 30% and the aromatic carbon increases to 60.50% at 300℃.
Abstract: The carbon atom chemical structure of three Wangqing oil shales was characterized by 13C-NMR techniques, and twelve important parameters of the carbon skeleton structure were obtained.Thermogravimetric-Fourier transform infrared spectroscopy (TG-FTIR) tests were used to obtain the formation of light gases during pyrolysis at 50℃/min and the final temperature of 600℃.The FLASHCHAIN model, which was established based on the structure of fuel, was employed to simulate the evolution of pyrolysis products and compared with the experimental tests.The results show that the model has a good simulation below 520℃, some errors occur above 520℃ due to the influence of secondary pyrolysis reactions and decomposition of minerals in the shale.The errors increase gradually with the increasing pyrolysis temperature.
Abstract: The characteristics of products from Shenfu coal pyrolysis-activation coupling reaction were investigated in a two-stage fixed bed reactor.The effect of pyrolysis temperature and activating agents (H2O (g), CO2 and H2O (g)/CO2) on the characteristics of products was analyzed.The mechanism of pyrolysis-activation coupling reaction was revealed.The results show that the pyrolysis temperature has little effect on the CO2 chemical reactivity of the chars.The tar yield of Shenfu coal pyrolysis is significantly increased by using pyrolysis-activation coupling process, and the tar yield is up to 17.8%.The effect of different activating agents on the yield of mixed coal gases (MCG) and tar is in the order of H2O (g)>H2O (g)/CO2>CO2 and the main components of tar are saturates and aromatics.The specific surface area of activated carbon can be effectively improved by using H2O (g)/CO2 as the activating agents, and the BET specific surface area reaches to 845.37 m2/g.The mechanism of pyrolysis-activation coupling process is that the synthesis gases (SG) from the activation section can provide hydrogen source for coal hydropyrolysis in pyrolysis section, and the rich hydrogen radicals can promote the reaction and change the product distribution and properties.
Abstract: The effect of iron ore on pyrolysis characteristics of a low rank coal from Hami was explored.By means of thermogravimetric analyzer (TGA), fixed bed reactor, fourier transform infrared spectroscopy (FT-IR), gas chromatograph (GC) and gas chromatography-mass spectrometer (GC-MS), the changes of pyrolysis reactivity, products distribution, the functional groups in the tar and the composition of tar of three coal samples were investigated and analyzed.The results show that when the pyrolysis temperature increases from room temperature to 150℃, the peak of weight loss rate of HM-CT and HM-JT gradually moves to high temperature.When the pyrolysis temperature is more than 450℃, the catalytic effect of different iron ores on coal pyrolysis is more obvious and in the order of specularite> the inherent minerals in HM> hematite.When the two kinds of iron ores added are up to 20%, there is a higher pyrolysis tar and gas yield.The tar yield is 7.88% for HM-JT coal sample and the yield of H2, CH4, CO2 and CO increases by 4.27%, 3.76%, 4.39% and 3.61%, respectively, compared with HM coal.For HM-CT coal sample, the tar catalytic cracking is influenced by the additive amount of iron ore.As the additive amount of specularite and hematite is increasing to 20%, the yield of tar decreases gradually, while the light tar yield rises to 6.37% and 5.34%, respectively for two iron ores, and the light tar fraction increases to 58.48% and 56.22%, respectively.Besides, the removal of oxygen in tar reaches to 43.16% and 36.89%, respectively.With the addition of iron ore, the relative content of m/p-xylene in tar decreases from 4.32% to 3.78% and 3.93%, respectively for two iron ores, and the relative content of toluene increases from 1.11% to 1.32% and 1.45%, respectively.The methyl substituents of o-cresol and m/p-xylenol molecules in tar are removed to produce phenol or cresol, and the demethylation for benzene series and phenolic compounds in tar on the specularite is stronger than that on the hematite.
Abstract: High alkali metal coal from four coal mines in Zhundong coalfield and its gasification fly ash were used to investigate the occurrence of alkali metal with five pretreatment methods including low temperature ashing,microwave digestion,national standards,cascade extraction and oxygen bomb combustion.The results show that the sodium in the high alkali metal coal exists mainly in the water soluble form,and the potassium is in the water insoluble form;The method of oxygen bomb combustion is the optimum one to determine the content of Na and K in high alkali coal and gasification fly ash,and the method of cascade extraction is also a better one to determine the content of Na.
Abstract: The influence of coal tar distillates on coke formation during the processing of Liaohe heavy crude oil with the distillates was studied.The composition of feedstock was characterized by the elemental analysis,the proton nuclear magnetic resonance spectrometry,the synchronous fluorescence spectrometry and the group analysis techniques.It has been found that the coke formation of Liaohe heavy crude oil upon heating can be reduced by co-processing with the coal tar distillates.Under the experimental conditions,the coke yields from the co-processing(0.5%-5.9%) are lower than that from the weighted calculation(3.3%-6.4%);a positive synergetic effect was observed.The extent of the synergetic effect depends on the chemical composition and content of the distillates.Saturates,1-ring aromatics and condensed 4-ring aromatics may retard the coke formation,whereas 2-ring and 3-ring aromatics as well as condensed 2-ring aromatics may retard the coke formation.
Abstract: Saudi Arabia atmospheric residue (SZAR) was subjected to supercritical fluid extraction fractionation (SFEF) and separated into four extractable fractions and an un-extractable end-cut.The SFEF subfractions were subjected to the simulated distillation analysis, gel permeation chromatography (GPC) for their molecular weight distributions, and open column liquid chromatography for their saturates, aromatics, resins, and asphaltenes (SARA) compositions, by high-temperature gas chromatography (GC).The density, carbon residue value, viscosity, and sulfur and nitrogen content along with the extraction pressure were determined.Sulfur compounds in wide fractions were converted to methylsulfonium salts, which were characterized by positive-ion electrospray ionization (ESI) and Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry (MS).The results indicated that the mass range and maximum peak intensity of the SFEF subfraction are increased as the SFEF subfraction becomes heavier.The molecules in various SFEF subfractions are separated by their polarity and molecular weight.The highest level in the various fractions is referred to S1 class species and meanwhile, benzothiophene turns to be the dominant heteroatom compounds.Compared with the lighter fractions, heavier fractions have higher contents of S1 and S2 class species, wider range, higher molecular weight, and more aromatic cores.
Abstract: The characteristics of high-sodium Zhundong coal in chemical looping combustion (CLC) as well as the migration of sodium upon combustion were investigated in a fluidized-bed reactor with natural hematite as the oxygen carrier, in order to mitigate the severe slagging and fouling problems and enhance the utilization efficiency of Zhundong coal.The results indicated that the carbon conversion and reaction rate for Zhundong coal in CLC were evidently higher than those of other coals at 850-1 000℃; aluminosilicate Na2O·Al2O3·6SiO2 of high melting point is formed in the CLC process, which is effective to mitigate the severe slagging and fouling problems.During a 10-cycle CLC test, the reactivity of hematite increases with the increase of cycle number, whereas the sodium content in the CLC fly ash is reduced.
Abstract: A kind of rotating gliding arc (RGA) argon plasma co-driven by tangential flow and magnetic field was investigated and used for hydrogen production from methane decomposition.In order to obtain insights into the physical characteristics of the RGA plasma, optical emission spectroscopy (OES) analysis was used to determine the electron temperature and electron density.In addition, the effects of feed flow rate and CH4/Ar ratio on the performance of the methane decomposition process in this RGA plasma were also investigated.Results have shown that, the RGA plasma is a kind of unique plasma between thermal and non-thermal plasma, with electron temperature of 1.0-2.0 eV and electron density of 1015 cm-3.In this system, the CH4 conversion could be 22.1%-70.2% and it increased with the increase of flow rate or CH4/Ar ratio.The H2 selectivity varied from 21.2% to 61.2%, and with the augment of flow rate, the H2 selectivity first varied slightly and then increased.A comparison of different non-thermal plasmas (e.g., microwave, radio frequency, and dielectric barrier discharge) showed that the RGA plasma could provide a relatively high CH4 conversion and H2 selectivity, as well as a relatively low energy consumption for H2 production, while maintaining a high flow rate (i.e., processing capacity) of 6-20 L/min.
Abstract: To improve the utilization of chemicals in bio-oil, recovery of phenolic compounds from high temperature bio-oil fractions by metal ion precipitation was studied.The effects of concentration of sodium hydroxide solution, reaction temperature and reaction time on the recovery of phenolic compounds by magnesium ion were examined using gas chromatography-mass spectrometry (GC-MS).The results demonstrate that the precipitation was formed instead of a salt of magnesium phenols.The optimum reaction conditions are reaction temperature of 25℃, 2.5 mol/L of sodium hydroxide solution, and reaction time of 20 min.In this case, the recovery of 4-ethylphenol from high temperature bio-oil fractions reaches 34.97%.
Abstract: A carbon material was prepared from the high temperature carbonization of waste camellia seed shell in a fluidized bed tubular reactor.The carbon material was applied as the catalyst support to prepare a new catalyst SO42-/Nd2O3/C after it was simultaneously modified by Nd3+ and sulfonated by concentrated sulfuric acid through impregnation method.The catalyst was characterized by several physical and chemical characterization methods.The catalytic activity and reusability of SO42-/Nd2O3/C were evaluated using it to catalyze the esterification of methanol and oleic acid for the synthesis of biodiesel.Results showed that the conversion of oleic acid was 96.70% when the methanol/oleic acid molar ratio was 2:1, reaction temperature was 90℃, and catalyst/reactants was 2% under reflux condensation for 120 min.After recycling of three times, the conversion of oleic acid was still 86.74%.High activity can be explained as follows:the electro-negativity of Nd is 1.14, which is smaller than O (3.44) and S (2.58), so it will provide lone electron pair to the empty 2p orbit of O and S, resulting in the formation of a stable coordination bond between Nd3+ and SO42-.In addition, S=O double bond can induce a strong electron withdrawing effect, which can increase the electrostatic field of Nd3+ when it was coordinated with SO42-.And finally, it should be noticed that H2O is a strong ligand.Hence, SO42-/Nd2O3/C exhibited a strong Br nsted acidity when H2O existed in the reaction medium.
Abstract: A series of SiO2-coated CuFe (SiO2@CuFe) catalysts with different Cu/Fe molar ratios were prepared by co-reduction and in situ coating method.The physicochemical properties of the catalysts were characterized with XRD, TEM, SEM-EDS, XPS and H2-TPR techniques and N2 sorption experiment.It was shown that well-dispersed CuFe nanoparticles were completely coated by mesoporous silica in the as-prepared catalysts.The content of Cu-Fe composite oxide in the catalyst and the selectivity of total alcohols and C2+ alcohols both exhibit a volcano trend with the decrease of Cu/Fe molar ratios.When the Cu/Fe molar ratio was 1, the largest amount of CuFe2O4 was formed, consequently, causing the strongest interaction between Cu and Fe.In addition, the obtained catalyst possessed higher BET surface area and larger BJH pore volume than the other samples.Thus, alcohol products easily diffuse into/out of its pores, thus avoiding the further hydrogenation to hydrocarbons.As a result, it shows the highest selectivity to total alcohols and C2+ alcohols.
Abstract: A series of mixed Ce, W and Ti oxides catalysts have been prepared and employed to selective catalytic reduction of NO with ammonia (NH3-SCR).It was found that Ce-W@TiO2 exhibited the optimal catalytic activity.Over 90% of NO conversion could be obtained by the surface TiO2-coated Ce-W@TiO2 catalyst at 205-515℃.The presence of SO2 leads to a decrease of low-temperature NO catalytic conversion and an increase of NO conversion above 425℃ over various catalysts, while Ce-W@TiO2 exhibits the optimal low-temperature SO2 resistance.It is noted that introducing Ti into Ce-W mixed oxide via the conventional co-precipitation method attributed to the decrease of surface W atomic abundance and acidic sites as well as inferior low-temperature NO conversion and SO2 resistance.In contrast, the surface TiO2-coated Ce-W@TiO2 catalyst prepared via a modified aqueous-phase method exhibit increased surface W atomic abundance and acidic sites as well as the superior low-temperature NO conversion and SO2 resistance.
Abstract: Effects of SO2 on performance of Mn-Ce/TiO2 catalysts were investigated in the selective catalytic reduction of NO with NH3.The catalysts were characterized by BET surface area, X-ray diffraction (XRD), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), respectively.The results show that SO2 has inhibitory effect on the selective catalytic reduction (SCR), and NOx conversion decreases from 84% to 42% at 140℃.This is mainly because the presence of SO2 results in the decrease of the specific surface area of the catalysis and the pore size distribution of 5-10 nm.SO2 can cause TiO2 transformation from anatase to rutile phase, the crystallization phenomenon of active components MnOx, and the decrease of the strong interaction between Mn and Ti.The variations of physical and chemical properties of poisoned Mn-Ce/TiO2 catalyst block the O2-→O-→O2- conversion path, which reduces the proportion of higher catalytic activity component MnO2 in MnOx, weakens oxygen storage ability of CeOx, and accumulates absorbed oxygen on the catalyst surface decreasing the adsorption and desorption of NO on active sites.Ammonium sulfate formed on the catalyst surface covers the Lewis acid sites and decreases the adsorption amount of NH3.
Abstract: A self-made experimental system was used to study the catalytic oxidation of low-concentration coal mine gases to methanol in acetic acid solution.With Pd(OAc)2 as catalyst, addition of p-benzoquinone or chloranil in the reaction system provides a beneficial environment for activation of methane, and chloranil shows a more positive effect.Chloranil amount and reaction temperature and pressure are the key factors influencing the catalytic properties.The target product yield has a positive relationship with these three factors.CH3OH is formed from the reaction of generated H2O2 and CH4.CH3COOCH3 is generated via two routes;one is direct oxidation of Pd2+ and CH4, the other is esterification of CH3OH and CH3COOH.
Abstract: An advanced hydrogenation catalyst was designed based on the good properties of encapsulated noble metal catalysts, which could be applied in the shape selectivity and hydrogen spillover reactions.Pt, sodalite zeolites and Pt (NH3)4Cl2 were selected as the active components, carriers and metal precursors, respectively.Pt/SOD zeolites encapsulated with different amounts of Pt were hydrothermal synthesized.Then benzene hydrogenation reaction was used as probe reaction to test the catalytic activity of the samples.XRD, SEM, TEM and H2-TPD were used to characterized the catalysts.The results showed that all Pt/SOD samples had good catalytic activity and excellent hydrogen spillover effect with spillover hydrogen acceptor HZSM-5.When the dosage of Pt (NH3)4Cl2 was 0.063 6 g ((Pt (NH3)4Cl2):(Si-Al gel)=0.030 g/g), the Pt/SOD sample obtained showed the highest catalytic activity for benzene hydrogenation and the benzene conversion was 54.38%.
Abstract: The modification of NaY by chromium ion was systemically studied.The modified CrY molecular sieve was characterized by X-ray diffraction (XRD), Fourier transform infrared spectrum (FT-IR) and nitrogen adsorption.The experimental results show that the optimum condition of modification are two times modification with 0.5 mol/L Cr3+at 40℃.The result of FT-IR suggested the peak disappeared at 1 147 cm-1 and the peak generated a blue shift at 1 024 cm-1, indicating that Cr3+ had exchanged Na+ in the framework of NaY molecular sieve.Static adsorption denitrification of a model fuel on CrY molecular sieve had carried out at different adsorption time and temperature.The results showed that the adsorption of quinoline on CrY molecular sieve was chemical adsorption and the adsorption type was coordination adsorption and π complex adsorption.The adsorption effect was better at room temperature for 30 min.The adsorption of quinoline over CrY molecular sieve belongs to Langmuir adsorption and Freundlich adsorption model.
Supervisor：Chinese Academy of Sciences
Sponsors by：Shanxi Institute of Coal Chemistry, Chinese Academy of Sciences Chinese Chemical Society
