Abstract: This study is to examine the changes in Cl volatilizations and chemical forms in NaCl-loaded Victorian brown coal during gasification in steam at 800 ℃ using Cl K-edge X-ray absorption near-edge structure (XANES) spectroscopy. The char samples were prepared in a novel one-stage fluidised-bed/fixed-bed quartz reactor at a fast heating rate. The samples were then collected and sealed in an argon-filled bag in order to minimise possible oxidation of char and Cl by air prior to analysis by XANES. Char-steam reactions were found to significantly affect the transformation of Cl, including the possible formation of chlorine-containing organic structures. On the other hand, volatile-char interactions during the gasification appeared to enhance the Cl retention and prevent the formation of organic chlorine compounds in chars.
Abstract: Ash flow temperature (FT) is an important index for coal gasification, determining the slagging model of coal-combustion and gasification process. On the basis of flow temperature of 181 coal ash samples, the FT prediction model associated with ash composition and acid/basic ratio was set up. The correlation coefficient is 0.934, indicating the FT prediction values is in good agreement with the experiment values. The liquidus temperature was calculated by FactSage software. The formula between FT and the liquidus temperature was established, and the correlation coefficient is 0.924.
Abstract: Decalin cracking over Y and ZSM-5 zeolites were conducted in a small fixed fluidised bed (FFB) reactor; the effect of temperature and catalyst/oil ratio on the opening of naphthenic ring in decalin cracking over Y zeolite was investigated. The results showed that the products of decalin cracking over zeolite catalysts by naphthenic ring opening involve non-aromatics (propane, propylene, butane, butylenes, methylpenptane, cyclopentane, cyclohexane, etc.) and monocyclic aromatics (benzene, and C1~4 alkyl benzene); polycyclic aromatics (tetrahydronaphthalene, naphthalene, alkyl naphthalene, phenanthrenes, pyrenes, etc.) and even coke may also be formed through dehydrogenation condensation reactions. The selectivity for naphthenic ring opening over ZSM-5 catalyst is higher than that over Y catalyst, due to difference in the diffusion and adsorption of naphthenic hydrocarbon on two catalysts. The relative ratio of naphthenic ring opening to dehydrogenation condensation reactions (NRO/DHC) is higher over ZSM-5 catalyst than that over Y catalyst. Under the conditions of 450~550 ℃, weight hourly space velocity of 10 h-1, and catalyst/oil mass ratio of 3~9, with the increase of the reaction temperature or the catalyst/oil ratio, the bimolecular hydrogen transfer and dehydrogenation condensation are enhanced and as a result, the selectivity to the products from naphthenic ring opening is decreased.
Abstract: Solid acid catalyst SO42-/ZrO2 modified by doping Al was prepared by co-precipitation-impregnation method and characterized by infrared spectrum. The activities of fresh, reused and regenerated catalysts were investigated by esterification with glycerol for deacidification of high-acid biodiesel feedstock. The activity of the catalyst SO42-/ZrO2 modified by 1% Al2O3, whatever the catalyst was in fresh or reused or regenerated condition, was better than that of non-modified SO42-/ZrO2. Al can increase the amount of SO42- on the catalyst, strengthen the combination between S and O, and decrease the loss of SO42- in the esterification process. The conversion of esterification was above 91% under the conditions of atmospheric pressure, 140 ℃ for 4 h, glycerol and fatty acid mole ratio of 6, and SO42-/ZrO2-Al2O3 catalyst dosage (catalyst/oil) of 7%.The acid value of the oil was reduced from 31 mgKOH/g to 2.8 mgKOH/g after esterification under above optimum conditions. This low-acid oil is suitable as the raw material of biodiesel.
Abstract: The 15%(Co-Mn)/TiO2,(Co/Mn=1/6) catalyst was prepared using fusion procedure and studied for the conversion of synthesis gas to C2~4 olefins. The effects of calcination conditions and operation conditions such as the H2/CO molar feed ratio at different temperatures, gas hourly space velocity (GHSV) and total reaction pressure on the catalytic performance of catalyst were investigated. The stability of the catalyst during 150 h at optimal operation conditions (t=250 ℃ H2/CO=2/1, GHSV=1 500 h-1 and p=0.3 MPa) has been investigated. It is found that this catalyst is high stable for production C2~4 olefins. Characterizations of both precursors and calcined catalysts by powder X-ray diffraction, scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) specific surface area measurement and thermal analysis methods such as thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC) show that the different preparation method influences the catalyst precursor structure and morphology.
Abstract: The interactions between sulfur-containing compounds of dibenzothiophene (DBT) and dibenzothiophene sulfone (DBTO2) and ionic liquids of 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM]+[PF6]-) and 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]+[BF4]-) were comparatively studied by using density functional theory. The most stable structures of [BMIM]+[PF6]-, [BMIM]+[PF6]--DBT, [BMIM]+[PF6]--DBTO2, [BMIM]+[BF4]-, [BMIM]+[BF4]--DBT, and [BMIM]+[BF4]--DBTO2 systems were obtained by natural bond orbitals (NBO) and atoms in molecules (AIM) analyses. The results indicated that DBT and [BMIM] rings of [BMIM]+[PF6]-/[BMIM]+[BF4]- are parallel to each other. There is a strong π-π interaction between them in terms of NBO and AIM analyses. The H1' and H9' involved F…H hydrogen bonding interactions may favor the formation of π-π stacking interactions. The DBTO2 preferentially locates near the C2-H2 and methyl group of [BMIM]+ to form O…H interactions. The predicted geometries and interaction energies imply the preferential adsorption of DBTO2 on [BMIM]+[PF6]-/[BMIM]+[BF4]-. The [BMIM]+[PF6]-/[BF4]- have better extracting ability to remove DBTO2 than DBT, possibly due to the larger polarity of DBTO2 and stronger interactions between [BMIM]+[PF6]-/[BF4]- and DBTO2.
Abstract: PtSn anode catalyst supported on carbon fiber was taken as the anode catalyst of the MEA. Commercial Pt/C catalyst was used in MEA as the cathode catalyst. The Nafion 115 membrane was the proton exchange membrane of the MEA. MEA was fabricated by hot-pressing. The sing flat cell was assembled with the prepared MEA. The influences of temperature, ethanol concentration, rates of liquor and O2 were studied. The results showed that the performance of the fuel was better when the concentration of ethanol was 1.0 mol/L, the rate of liquor was 1.0 mL/min, the temperature was 80 ℃, and the rate of O2 was 100 mL/min, the maximum power density of the fuel reached about 18.2 mW/cm2.
Abstract: Chitosan-carbon composite material (CHI-C) was prepared. Pt-Au catalysts supported on chitosan-modified carbon black with different Pt/Au atomic ratios were prepared by a sol immobilization method. The samples were characterized by UV-visible absorption spectroscopy, X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy. The activity and stability for methanol electrocatalytic oxidation reaction were evaluated by cyclic voltammetry and chronoamperograms, respectively. The effects of Pt/Au atomic ratios and chitosan modification on the activities and stabilities were studied. As a result, Pt1.0＾Au/C catalyst showed the best catalytic activity. Adding small amount CHI to carbon black support can improve the stability of Pt1.0＾Au/C catalyst.
Abstract: Spinel oxides of CuAl2O4, CuFe2O4 and CuCr2O4 were prepared by citrate process at 900 ℃, and their catalytic properties for methanol steam reforming was evaluated. In combination with the XRD, H2-TPR, SEM and BET data, the catalytic characteristics of spinel oxides were also discussed. The results showed that the morphology and size of the three spinel oxides were quite different and catalytic properties varied among the three spinel oxide catalysts. CuAl2O spinel showed the highest stability and lowest CO selectivity while CuFe2O4 indicated the highest CO selectivity and poor stability and CuCr2O4 encountered serious coke deposition. It has been shown, according to the long test data and results, that active Cu species were released from copper based spinel during methanol steam reforming, and their catalytic performances were influenced by both Cu sintering and coke deposition.
Abstract: Modified zirconia (ZrO2) were synthesized by high temperature calcination of ZrO(OH)2 gels digested in alkalic solution; with the modified ZrO2 as support, ruthenium catalysts for ammonia synthesis were prepared with K2RuO4 solution. The catalysts were characterized by X-ray diffraction (XRD), temperature programmed reduction of hydrogen (H2-TPR), temperature programmed desorption of CO2 (CO2-TPD), nitrogen sorption, X-ray fluorescence spectroscopy (XRF), and CO chemisorption; the relationship between the catalyst structure and its catalytic activity was especially discussed. The results revealed that the digestion either in KOH or NH4OH solution can enhance the surface area of the ZrO2 support, while digestion in KOH is able to obtain the support with high basicity, which benefits to getting the ruthenium catalyst of high activity. The strong basicity of the modified ZrO2 support, rather than the high ruthenium dispersion, plays a more important role in enhancing the activity of the supported ruthenium catalyst. For ammonia synthesis under 425 ℃, 5 MPa and a space velocity of 10 000 h-1, NH3 outlet concentration over Ru/ZrO2-KOH is 5.96%, which is 11%, 143% and 103% higher than those of K-Ru/ZrO2-NH4OH, K-Ru/ZrO2-CP and Ru/ZrO2-NH4OH, respectively.
Abstract: A series of cerium-incorporated X zeolites (Ce(IV)-X) with different Ce/Si molar ratios were prepared by in situ hydrothermal synthesis and used as adsorbents to remove thiophene from a model fuel. The synthesized Ce(IV)-X zeolites were characterized by X-ray diffraction (XRD), fourier transform infrared spectroscopy (FT-IR), diffuse reflectance ultraviolet spectroscopy (UV-vis DRS), plasma atomic emission spectrometry (ICP-AES), N2 adsorption, and NH3 temperature programmed desorption (NH3-TPD). Results reveal that the synthesized Ce(IV)-X zeolites exhibit typical structure of X zeolites and cerium (IV) ions are well dispersed in the framework of X zeolites. The acidity of Ce(IV)-X is enhanced by incorporating cerium, especially at high cerium content. The synthesised Ce(IV)-X zeolites exhibit better capability for the adsorption of thiophene from the model fuel than X zeolites; the Ce(IV)-X sample with n(Ce)/n(Si)=0.05 performs best, possessing a saturated adsorption amount of 52.541 9 mg/g. Moreover, the spent Ce(IV)-X after regeneration still has a perfect adsorption ability towards thiophene; the regenerated Ce(IV)-X sample with n(Ce)/n(Si)=0.05 has a saturated adsorption amount of 47.512 1 mg/g, i.e. 90.43％ of that for the fresh adsorbent.
Abstract: The poisoning effects of alkali metals on low-temperature selective catalytic reduction (SCR) catalyst MnOx-CeO2/ZrO2-PILC were invested by the method of impregnation in the laboratory. It was indicated that the addition of Ca/Mg would decrease the activities of the catalyst, and the poisoning effects were contacted with the amount and acidity of the doped-alkali metal. X-ray diffraction (XRD), H2-temperature programmed reduction (H2-TPR), N2 adsorption-desorption and temperature-programmed desorption of NH3 (NH3-TPD) were used to characterize the properties of the fresh and alkali earth doped catalysts. According to the results, the doped-alkali metals would inhibit the reduction properties, induce the loss in surface area and surface acidity.
Abstract: γ-Al2O3 supported catalysts with different Ni/W atomic ratios for the hydroprocessing of low temperature coal tar (LTCT) were prepared and characterized by BET, XRD, H2-TPR and TG analysis. The hydroprocessing of <350 ℃ fraction of LTCT was carried out in a fixed-bed reactor. The product distribution and composition were analyzed by distillation, GC/MS, fluorescent indicator adsorption and elementary analysis. The results show that NiO and WO3 are evenly distributed on the support surface; and low-loading NiO is difficult to reduce since the strong force is formed with the support surface. The phenol conversion, the selectivity of kerosene fraction and the content of naphthene and hydro-aromatic in the product are the highest at a Ni/W atomic ratio of 0.38, while the activities of HDS and HDN and the H/C atomic ratio in the product are also the best. It indicates that the NiW/γ-Al2O3 catalyst with an optimum Ni/W atomic ratio of 0.38 is appropriate for the hydroprocessing of LTCT.
Abstract: In an attempt to develop a novel and more effective sorbent with low-cost for the removal of gas-phase Hg0 from flue gas, the adsorption performance of semi-coke and KMnO4 solution-modified semi-coke for gas-phase Hg0 was investigated with a bench-scale fixed-bed reactor system. The experimental results suggest that the adsorption performance of semi-coke is good at low temperature but weak at higher temperature. The semi-cokes impregnated by KMnO4 solution have excellent adsorption performance for gas-phase Hg0 at 140 ℃, and can be further enhanced by heating the impregnated samples at 250 ℃. The BET analysis shows that the semi-coke has rich micro-pores but become poor after modification. The XPS results indicates that the adsorbed mercury on the surface of the modified semi-coke samples mainly exists in oxidation state (Hg2+) and these compounds (KMnO4, K2MnO4 and MnO2 ) play a key role in the oxidation reaction of gas-phase Hg0.
Abstract: The direct sulfation reaction of limestone modified by wood vinegar, a kind of waste liquid, was investigated by thermogravimetic analysis method under O2/CO2 atmosphere. The results show that the direct sulfation performance of limestone can be effectively improved by wood vinegar modifying in the experimental temperature range (1 023~1 173 K). The phase composition analysis measured by XRD shows that the major composition in the modified limestone is hydration calcium acetate. The structure of limestone modified is much looser than that of original limestone, which is conducive to the direct sulfation reaction. The direct sulfation rate constant (ks) and product-layer diffusivity (Deff) in Arrhenius expressions were calculated according to the shrinking unreacted core model. The kinetic calculation results show that the diffusion impact of limestone modified by wood vinegar on the direct sulfation process is less than that of original limestone, which means that the limestone modified by wood vinegar has a lower diffusion resistance.
Abstract: On the basis of the leaching characteristics of heavy metals in the fly ash collected from a co-combustion plant of MSW and sewage sludge, the volatilization of heavy metals (Pb, Cd, Cu and Zn) were studied at 1 000 ℃with different residence time. Meanwhile, the influence of solid additive agents (CaO, Al2O3, SiO2, kaolinite and coal ash) was studied. The results show that the contents of Zn, Pb, Mn in fly ash are high, Ni is low and Cd content reaches 29.4 mg/kg. The metals concentrations in leaching solution, changing a great with leaching solution pH and extraction time, meet the hazardous waste identification criteria (GB5085.3-1996).The volatilization of heavy metals has great differences with the order of Pb> Cd> Zn> Cu, in which the volatilization rate of Pb is higher than 80% and that of Cu is less than 30%. In the thermal disposal process, the volatilization rate is influenced by the residence time, and the volatile elements Pb and Cd are particularly evident.The volatilization of Cd reduces after adding Al2O3 and kaolinite, and that of Pb reduced after adding Al2O3. Zn evaporation rate decreases with adding SiO2, CaO, kaolinite and coal ash, while that of Cu is not changed. This is related to the high Cl content in fly ash and the competitive adsorption selectivity of the trace element compounds on the active sites of solid additives.
Supervisor：Chinese Academy of Sciences
Sponsors by：Shanxi Institute of Coal Chemistry, Chinese Academy of Sciences Chinese Chemical Society
