Abstract: Shendong Shangwan coal (SDR) and its inertinite concentrated(SDI)from petrographical separation were characterized by 13C-CP/MAS NMR, FT-IR and XPS and their structure unit information was obtained. Based on structure parameters and elemental analysis, macromolecular structure models of SDR and SDI were constructed and 13C chemical shift of the two models was calculated by ACD/CNMR predictor. The results indicate that naphthalene with condensation degrees of 2 is the main form of aromatic carbon in SDR, naphthalene and phenanthrene are those in SDI. The aromaticity of SDI is greater than that of SDR. For SDR and SDI, oxygen atoms are present as carbonyl groups and nitrogen atoms exist in the forms of pyridine and pyrrole. The calculated chemical shift spectrogram of model is well consistent with that of the experimental results. The structural formulas calculated for SDR and SDI are C181H136N2O24 and C186H148N2O22, respectively.
Abstract: The chemical looping combustion of coal with NiO/Al2O3 oxygen carrier was experimentally investigated in a 1 kWth interconnected fluidized bed. The carbon conversion ηC,coal, the conversion of gaseous products, the carbon capture efficiency ηC,cap and the coal combustion efficiency ηcombust were calculated and discussed. Several influencing factors including the temperature tFR, excess air coefficy α, the ratio of steam flow rate in the loopseal to the feed coal SLS/C, the ratio of steam flow rate in the fuel reactor to the feed coal SFR/C were examined. The results indicate that the increase in either tFR or SLS/C is favorable for increasing ηC,coal and the conversion of gas products from coal gasification. A larger α can also give a higher ηC,coal. With the SFR/C increasing from 0.8 to 1.6, ηC,coal first increases and then decreases with the maximum at SFR/C=1.2. ηcombust has the same trends as ηC,coal; it is mainly affected by the loss of carbon in the fly ash. Contrary to α or SLS/C, increasing TFR can give a higher ηC,cap.
Abstract: The pyrolysis of syringol as lignin model compound was investigated using density functional theory methods at B3LYP/6-31G++ (d, p) level. Three possible pyrolytic pathways were proposed and the equilibrium geometries of the reactants, transition states, intermediate and products were fully optimized. The standard kinetic parameters in each reaction pathway were calculated and the formation and evolution mechanism of main pyrolysis products were analyzed. Bond dissociation energies calculation results show that the bond dissociation energy of CH3-O of syringol is the lowest and the order of all kinds of bond dissociation energy is CH3-O < O-H < CH3O-Caromatic < CH2-H < HO-Caromatic < Caromatic-H. In reaction pathway 1 and 2, the main pyrolysis product is 3-methoxycatechol and 2-methoxy-6-methylphenol, respectively. The total energy barrier is 366.6 and 474.8 kJ/mol in pathway 1 and 2, respectively. For reaction pathway 3, the total energy barrier of o-methoxyphenol formation is as low as 21.4 kJ/mol, which shows that addition of hydrogen to the carbon atom connected with methoxyl can effectively lower the reaction energy barrier of demethoxy reaction of lignin model syringol.
Abstract: The effects of ethyl acetate addition on the stability of bio-oil from rice straw fast pyrolysis were investigated through measuring the physicochemical properties of the bio-oil during storage. The results showed that by adding ethyl acetate of 1%, 6%, 11%, 16% and 21%, the final pH values of the bio-oils are increased by 0.66%, 2.33%, 3.65%, 4.32% and 6.31%, respectively; the final water contents are decreased by 10.90%, 20.17%, 28.19%, 30.27% and 35.10%, respectively; the final viscosities are decreased by 13.69%, 39.08%, 57.99%, 66.00% and 73.58%, respectively. The FT-IR and GC-MS analyses indicated that ethyl acetate can inhibit bio-oil from some aging reactions and reduce the content of organic acids.
Abstract: The migration behavior of alkali metals during co-gasification of cornstalk and PE in a fixed bed at different temperatures was studied on the thermodynamic equilibrium calculation, the X-ray power diffraction and scanning electron microscope/energy dispersive spectrometer. The results indicat that the alkali chlorides (KCl、K2Cl2、NaCl)are the main components in gaseous. There is a large amounts of C and H in the fules with the mixed of plastic PE. The H makes the Cl prefer HCl to KCl, meanwhile, the release radio of K is lower than the cornstalk gasification cause of the C easily reacted with K than Na. Alkali metal compounds in ashes are mainly in the forms of KCl, NaCl, K2SO4, KAlSi3O8, KAlSiO4, NaAlSi3O8, NaAlSiO4. The KCl,NaCl begin to release when the reacting temperature above 800℃ and most of K,Na,Cl are easily deposited on the edge of the hole.
Abstract: The external reason of the viscosity of Binnan super heavy oil from Shengli oil field was investigated. The properties of the super heavy oil showed that the viscosity of the oil mainly depended on two factors: the total resin and asphaltene content are larger than 30%, the enhanced cohesion of asphaltene by macrocyclic compound formed by the metallic element like Ni and the heteroatoms like O,N, and S.The viscosity reducing rate reached 99.59% by using the viscosity reducer (OP-10). By comparing the change of resin and asphaltene before and after treatment, the analytical conclusions of IR and SEM, the molecular weights and the mean dipolemoments showed that: the hydrogen bond of resin and asphaltene can be weakened, the aggregation of asphaltene is partially broken up, so the molecular weights and the mean dipolemoments were decreased by the viscosity reducer (OP-10).So it is known that viscosity reducer can infiltrate and disperse into asphaltene molecules, so that the order of asphaltene molecules is lowered. At the same time, the microstructure analysis using polarization microscope of the emulsion and wax showed that the emulsion of super heavy oil from W/O were turned to O/W and the morphology of wax from fine uniform were turned to flocculating constituent of bigger size by the viscosity reducer (OP-10).
Abstract: Three inferior heavy oils from Venezuela, Liaohe and Karamay were chosen as the feedstocks, and the effect of heavy metals on the characteristics of coke formation during thermal conversion process was studied. The results indicate that the higher content of heavy metals, the shorter coke induction period. With the increasing of the content of heavy metals, the yield of coke is increased obviously; the coke particle size becomes larger. Furthermore, the analysis of product from the delayed coking process indicates that the oil with higher content of heavy metals produces a higher coke yield, but a lower yield of liquid.
Abstract: Three hydrocracking catalysts were prepared by impregnation method with different incorporation manners of Ni/W metals on HY/Al2O3 support. The effect of combination methods on acidity, hydrogenation capability of the catalysts and its hydrocracking performance on FT wax was studied. The balance between hydrogenation performance and cracking performance could be modulated by adjusting the metal-support combination methods. Ni/W pre-impregnated on HY can increase the hydrogenation capability of the catalyst and simultaneously lower the acidity of the support. The results show that the coordination of high hydrogenation capability and low acidity of catalyst can inhibit the formation of secondary cracking on some extent, and increase the selectivity of diesel. While Ni/W metals supported on HY/Al2O3 can achieve a relative balance of hydrogenation and cracking, thus the catalysts have a higher activity and the more flexible ability to modulate reaction.
Abstract: The synergetic effect between Ni2P/Al2O3 and MoS2/Al2O3 catalysts on their performance in the hydrodenitrogenation of quinoline was proved by a simplified experimental design and explained by the remote control model through a migration of hydrogen spillover. The results indicated that the synergism factor of Ni2P and MoS2 is slightly higher than that of NiSx and MoS2; it decreases with the increase of reaction temperature. Since the spillover hydrogen with Ni2P can increase the amount of hydrogenation active sites of MoS2, the hydrogenation rate of 1,2,3,4-tetrahydroquinoline and 5,6,7,8-tetrahydroquinoline to decahydroquinoline over the Ni2P/Al2O3 and MoS2/Al2O3 catalyst system is then greatly enhanced; as a result, Ni2P is a superior promoter for MoS2 catalyst for hydrodenitrogenation.
Abstract: The effect of calcination temperature on the performance of ZnCr based catalysts in isobutanol synthesis was investigated; the texture properties, bulk structure, reducibility and surface composition of the catalysts were characterized by BET, XRD, H2-TPR and XPS. The results indicate that both the activity and product selectivity of the ZnCr catalyst are greatly influenced by its calcination temperature. The catalyst calcined at low temperature shows high selectivity to methanol and isobutanol, while the product distribution over the catalyst calcined at high temperature obeys the A-S-F equation. Calcination at 300℃ is insufficient to get a complete formation of non-stoicheiometric spinel ZnxCr2/3(1-x)O, while calcination at 400℃ gives the maximum amount of non-stoichiometric spinel ZnxCr2/3(1-x)O in the ZnCr based catalyst; however, further increasing the calcination temperature may cause the decomposition of certain non-stoicheiometric spinel ZnxCr2/3(1-x)O to ZnO and Cr2O3, which will reduce its catalytic activity in isobutanol synthesis. Such results suggest that non-stoicheiometric spinel ZnxCr2/3(1-x)O is possibly the active phase of the ZnCr based catalyst in isobutanol synthesis.
Abstract: The active sites of reduced Mo/γ-Al2O3 and Co-Mo/γ-Al2O3 hydrotreating catalysts were studied by in-situ FT-IR using CO and NO as probe molecules; the results were correlated with their activity in hydrodesulfurization (HDS) and behavior in temperature programmed reduction (H2-TPR). The results indicate that there exist three main adsorption sites on the surface of Co-Mo/γ-Al2O3 catalysts. The addition of cobalt to Mo/γ-Al2O3 is able to modify Mo sites and to introduce active Co sites; an increase of the molybdenum content may also increase the number of active sites and improve the catalytic activity of Co-Mo/γ-Al2O3. FT-IR spectra of CO and NO co-adsorption is able to distinguish the spectra overlapping of different active sites, which reveals that CO and NO are actually adsorbed on different Mo active sites.
Abstract: Pt-S2O82-/ZrO2-Al2O3(Pt-SZA-X) solid superacid catalysts were prepared by microemulsion method and characterized by XRD, BET, FT-IR, TPR and TEM. The effects of calcination temperatures on the isomerization performance were studied by using n-pentane isomerization as a probe reaction. It was found that the calcination temperature has less influence on the reduction temperature of the Pt-SZA-X,but the S content over catalyst decreased with increasing calcination temperature. The O=S=O structure formed at calcination temperature range of 600 to 650℃ and the combination between of S and catalyst support was relatively stable. The pure monoclinic phase of ZrO2 were observed with sample calcined at 650℃. When the calcination temperature is higher than 650℃, the specific surface area decreases rapidly and the loss of S6+ on the surface of catalyst is seriously. Among the catalysts obtained at various calcination temperatures, the catalyst calcined at 650℃ has appropriate amount of superacid sites and surface area and the highest isomerization activity. At reaction temperature of 230℃, pressure of 2.0 MPa, hydrogen/hydrocarbon molar ratio of 4:1 and mass hourly space velocity of 1.0 h-1, the isopentane yield is 60.8%.
Abstract: A series of Ni/CeO2-Al2O3 catalysts were prepared by the methods of impregnation-precipitation, hydrothermal synthesis, co-precipitation and citric acid complexation. The effects of preparation method on the physical structures and catalytic performance of the resultant catalysts in partial oxidation of methane (POM) were investigated. The fresh and spent catalysts were characterized by N2 physical adsorption, X-ray diffraction (XRD), temperature-programmed reduction by hydrogen (H2-TPR), temperature programmed desorption of ammonia (NH3-TPD) and thermogravimetry (TG) analysis. The results show that Ni/CeO2-Al2O3 prepared by impregnation-precipitation method exhibits the lowest activity and selectivity to H2 and CO; the highest catalytic performance is achieved by the catalyst prepared through citric acid complexation. The Ni/CeO2-Al2O3 catalyst prepared by citric acid complexation has the largest specific surface area and the smallest CeO2 crystals with good dispersion. Both Ni species and NiAl2O4 spinel in Ni/CeO2-Al2O3 prepared by citric acid complexation are prone to being reduced to metal Ni, which can produce more active sites for methane partial oxidation reaction. There is more acidic sites and deposited carbon over the catalyst prepared by citric acid complexation; however, taking its high activity into account, its stability is relatively high with low carbon deposition rate.
Abstract: Zn-Fe spinel oxides were prepared by co-precipitation method and used as the catalysts in N2O decomposition in the presence of oxygen; the effects of spinel oxide composition, calcination temperature, and K doping on their catalytic activity were investigated. In addition, the Zn-Fe spinel oxides were characterized by N2 physisorption, X-ray diffraction and H2-TPR techniques. The results indicated that the Zn-Fe spinel oxides are active in N2O decomposition in the presence of oxygen; over the Zn0.8Fe0.2Fe2O4-400 catalyst with the optimized composition and calcined at 400℃, the conversions of N2O in the absence and in the presence of steam achieve 63.5% and 22.2%, respectively, after reaction at 500℃ for 10h, which are much higher than those over Fe3O4. However, the K-doped Zn-Fe spinel oxides exhibit lower activity than the bare Zn-Fe oxide, as K doping may lead to a substantial decrease of surface area and the migration of potassium crystallites to FeOx surface that will inhibit the ferric species from reduction and active oxygen species from removal from the catalyst surface.
Abstract: The RhB-P25 nanocomposites synthesized by low temperature calcination were used for visible light induced photocatalytic water splitting. It was confirmed by X-ray diffraction (XRD) and field emission scanning electron microscope(FESEM)characterization that the crystalline phase and morphology of P25 catalyst were not changed by calcination treatment. UV-visible absorption spectra and FT-IR spectra indicated that there was a strong mutual interaction between RhB and P25. PL spectra also proved that electrons could easily transfer from RhB to P25 after the low temperature calcination treatment. The highest rate of hydrogen evolution was observed for the sample calcined at 250℃,about 65.1 μmol/(g·h) under visible light irradiation, which was 1.8 times larger than that of the physical mixture of P25 and RhB.
Abstract: CuO/TiO2 composites were prepared by a simple impregnated method with Cu(NO3)2·3H2O and P25 as precursors. The characteristic of photocatalysts were analyzed by N2-physisorption, XRD, TEM, UV-vis DRS spectra. In this paper, the effects of Cu content, the scattered catalyst amount, calcination temperature of the photocatalyst and methanol concentration for the photocatalytic activity of CuO/TiO2 composites were studied. We also investigated the stability of the catalyst and proposed a mechanism of the photocatalytic process. The results suggested that the appropriate content of Cu component in CuO/TiO2 is 2.0%~7.5% and hydrogen production rate can reach 1 022 μmol/(h·g) at 2.0% of Cu content, 10% of methanol concentration, 350℃ of calcination temperature and 1.0 g/L of scattered catalyst amount. It was also demonstrated that CuO/TiO2 photocatalyst had a stable activity for H2 evolution.
Abstract: Serpentine was used as the mineral material for CO2 sequestration by direct mineral carbonation under medium and low pressure. A series number of experiments were carried out to investigate the factors that influence the conversion of carbonation reaction, such as temperature, pressure, particle size, solution composition and pretreatment. The results show that serpentine can be used to sequestrate CO2 in simulated flue gas by aqueous direct mineral carbonation under medium and low pressure. Carbonation conversion increases with increasing temperature and pressure. Decrease in mineral particle sizes and use of heat treatment before carbonation can effectively improve the conversion. The addition of NaHCO3, which has a buffering effect that kept the solution pH in a certain range, can also improve the carbonation conversion. The highest carbonation conversion of 47.7% and 36.3% was obtained in 60 min under 4 MPa and 150℃ for pure CO2 gas and simulated flue gas, respectively.
Abstract: With triethylamine (TEA) as structure directing agent, ZnSO4 as metal ion source and water as the solvent, zeolitic imidazolate framework-8 (ZIF-8) adsorbent was prepared by hydrothermal synthesis and used in the separation and enrichment of exhausted coal-bed methane. XRD, physical adsorption, dynamic adsorption equilibrium and inverse gas chromatography (IGC) methods were employed to characterize the physical structure, chemical stability, adsorption and separation performance of the ZIF-8 adsorbent; the adsorption thermodynamics of CH4 and N2 on it was also considered. The results indicated that ZIF-8 structure is stable in the acid, alkali and strongly polarized solvent. At 298 K, the separation factor of the ZIF-8 adsorbent towards CH4/N2 is up to 3.4, which is comparable to activated carbon; however, ZIF-8 should be more promising in practical application, because the adsorption heat over it is about 20% lower than that over activated carbon.
Abstract: The structure of anion-intercalated MgAl-layered double hydroxides (MgAl-LDHs) and the interaction between the anion and host layer were investigated by density functional theory (DFT); the anions considered were inorganic ones like F-, Cl-, NO3-, CO32- and SO42-, as well as organic ones like [p-(CH3)2N(C6H4)COO]-, [(C6H5)COO]-, [HO(C6H4)COO]-, [C12H25SO3]-, [C6H13SO3]- and [C3H7SO3]-. The geometric structures and interactional energies between the anions and host layer were obtained. The results showed that there is a strong supra-molecular interaction between anions and host layer of MgAl-LDHs and the interactional energy values followed the orders of CO32- > SO42- > F- > Cl- > NO3-, [p-(CH3)2N(C6H4)COO]- > [(C6H5)COO]- > [HO(C6H4)COO]-, and [C12H25SO3]- > [C6H13SO3]- > [C3H7SO3]-. In addition, the interaction mechanism between anions and host layer was considered by the natural bond orbital (NBO) analysis; the trend of stability energies calculated by the second order perturbation agrees well with that of the interactional energies.
Supervisor：Chinese Academy of Sciences
Sponsors by：Shanxi Institute of Coal Chemistry, Chinese Academy of Sciences Chinese Chemical Society
