Abstract: The raw coal and demineralized coal obtained from Yimin lignite were studied by Fourier transform infrared spectroscopy (FT-IR) with curve-fitting analysis to obtain the structure change information after demineralization. The results show that demineralization has little effect on aliphatic hydrogen and hydroxyl. The absorption intensity of CH2 asymmetric stretching vibration changed little, that of CH stretching vibration decreases, and that of CH2 symmetric stretching vibration and CH3 asymmetric stretching vibration increases. The absorption intensity of OH-N, OH-OH and OH-π hydrogen bonds decreases and that of ring hydroxyl and OH-O intensity increases. Demineralization has great effect on aromatic structures and oxygen-containing groups. Aromatic structures change from three hydrogens per ring dominating to three and four hydrogens per ring dominates. The absorption intensity of alkyl ether and aliphatic carboxylic acids decreases significantly after demineralization, which may be caused by hydrolysis reaction. The absorption intensity of phenolic hydroxyl and carboxylic acids increases greatly after demineralization.
Abstract: High purity vitrinite was separated and concentrated from New Zealand(NXL; St,ad=1.84%) and Shanxi(SX; St,ad=1.80%) coal which have similar sulfur content. The vitrinite was pyrolyzed in a tube furnace reactor under argon at 300, 500, 700 and 1 000 ℃. The effect of temperature on the functional group content and organic sulfur forms transformation was examined by Fourier transform infrared spectrum and X-ray photoelectron spectrum, respectively. The FT-IR experiments show that aliphatic hydrogen content in SX vitrinite and its reactivity is higher than those of NXL vitrinite at same temperature. The aliphatic hydrogen in both vitrinites decreases with increasing temperature. The aliphatic hydrogen content in SX and NXL vitrinite is unchanged when the temperature is above 500 and 700 ℃, respectively. The aromatic hydrogen increases first and then decreases with increasing temperature. The XPS results show that the organic sulphide, which is more thermal unstable, is richer on surface of SX vitrinite than that of NXL. It is decomposed completely below 300 and 700 ℃ for SX and NXL, respectively. The content of thiophenic compounds increases with increasing temperature, but that of sulfones compounds is just the reverse.
Abstract: A temperature-programmed tube furnace was set up to investigate the occurrence modes of mercury in coal according to its releasing temperature during pyrolysis. The fraction of mercury in each occurrence mode was determined by calculating the total released amount at different temperature ranges. The mechanism of mercury release inhabitation by CaCl2 was studied as well. The result showed that there are mainly three occurrence modes of mercury in coal: their release temperatures are 220, 300 and 400 ℃.The secondary mode released at 300 ℃ takes 54.18%, which should be HgS according to its decomposition temperature. The CaCl2 inhibited the release of mercury at 220 and 400 ℃. The inhabitation is mainly caused by mercury oxidation and adsorption. By adding CaCl2, the mercury release is focused to a certain temperature but the total release amount is hardly influenced.
Abstract: Ximeng lignite was pyrolyzed at different temperatures and different characteristics including coal property, slurry ability, rheological behavior and stability of coal water slurry made from char were investigated. Pyrolysis was conducted in absence of air. Viscosities of different density slurries were measured and the curves of rheological behavior were fit through shearing rate and apparent viscosity. Actual slurry density and stability was measured according to national standard method. The mechanism of pyrolysis for raw coal and char slurry was analyzed through the alteration of surface functional groups and pore structure. The results show that pyrolysis could reduce oxygen-containing functional groups in samples and bring down their hydrophilicity, which is benefit to the improvement of slurry density. Water slurry density shows first an increase, and then decrease with the rise of temperature. Pyrolysis seems to be unfavorable to the stability of slurry. Pore structure is changed a lot through pyrolysis due to the decomposition of oxygen-containing groups. Specific surface area and pore volume first increase, and then decrease, but average pore diameter shows a totally opposite trend.
Abstract: The CeO2/Fe2O3 oxygen carriers were prepared by co-precipitation method and their characterization was carried out using X-ray diffraction (XRD) and scanning electron microscope (SEM). The partial oxidation reforming of methane was tested in a fixed-bed at different operating conditions. The temperature programming results show that 30% CeO2-modified Fe2O3 has rather better effect than pure Fe2O3; the conversion of CH4, the selectivity of H2 and CO are greatly improved. Same results have been observed in isothermal experiments. As the reaction time is less than 1 200 s, there is no carbon deposit formed. After 15 cycles, 30% CeO2-modified Fe2O3 has the best cycling performance at 850 ℃ and the reaction time of 945 s. The conversion of CH4 reaches to 91.53%, the selectivity of H2 and CO reach to 86.36% and 85.12%, respectively and the H2/CO mol ratio in syngas is 2.03. The species of substance in oxygen carriers has no obvious change after 15 cycles.
Abstract: The effects of ash/K2CO3/Fe2O3 and their interactions on the ignition temperature and combustion rate of acid-washed anthracite were examined. The coal ashes from combustion of anthracite at different temperatures showed very different properties such as chemical compositions, color and morphology. Reactivities of demineralized anthracite with and without catalysts were measured by thermo-gravimetric analyzer (TG-DTG). The results indicate that ash itself has no catalytic effects on ignition temperature while the combustion rate is improved, especially by the ash prepared at high temperatures. The use of ash with K2CO3 (or Fe2O3) together as combustion catalysts reveals that the interactions (i.e. sintering reactions) between them have caused the reduction in combustion rate, compared with the cases when K2CO3 or Fe2O3 was employed individually. Similarly, the synergistic effect between K2CO3 and Fe2O3 was also observed to lower the combustion rate of demineralized anthracite.
Abstract: The transformation of K2CO3 in the course of Shenfu char catalytic pyrolysis under different temperatures was studied in the fixed-bed reactor; the influence of loading methods of K2CO3 and particle size on gasification reactivity was investigated in a TG-DSC analytical reactor. The results showed that with the increase of temperature, the effect of loading methods on gasification rate is weakened; K catalyst shows high dispersity by means of SEM/EDX analysis of pyrolysis residue. CO2 and CO are produced through the interaction of K2CO3 and coal char in the pyrolysis and there is a linear relation between the amount of released gas and temperature. The particle size of K2CO3 and coal char has notable impact on gasification; the gasification rate increase with a thinner particle at 650 ℃. K2CO3 shows high mobility within the coal char phase at elevated temperature, which is consistent with its catalytic activities; the effect of loading methods on gasification should be considered under a temperature below 700 ℃.
Abstract: The TG-FTIR anaylsis technology was applied to analyze the co-gasification process and gasification products of pine sawdust, lignite and their mixtures. The influence of mixing ratio, heating rate and reaction atmosphere on the co-gasification process was also studied. The results show that the pine sawdust can improve the reactivity of samples. As the mixing ratio of pine sawdust is increasing, the mass loss rate of gasification decreases, and the beginning temperature and the peak area of CO formation have a decreasing tendency. It is found that the lower heating rate is advantageous to the formation of CO and CH4. With increasing the heating rate, the DTG curves move to higher temperature ranges, the maximum weight loss rate increases, and the pine sawdust peak disappears. The effect of CO2 atmosphere on the weight loss of devolatilization is not significant. The two peaks of devolatilization are corresponding to the volatile combustion and fixed carbon combustion in air, and the coke gasification is not significant in the atmosphere of air.
Abstract: The characteristics of components of heavy oil, their interactions and effects on the wax deposition behavior of heavy oil from Yumen oil field were studied by using chromatogram separation, Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC) and optical microscope. The results indicate that the interaction between the components can inhibit the precipitation of wax crystal effectively. The behaviors of A1 with different polarity components added are quite different from that of the heavy oil. The wax-appearing temperature, the peak temperature of wax-precipitation and the percentage of precipitated wax are decreased. The optical microscope analysis shows that the addition of resin and asphaltene to A1 can increase the number of wax crystal particles and decrease their dimensions during the cooling crystallization process, which can prevent the particles from contacting and crosslinking each other to form bulk wax crystal aggregation.
Abstract: The adsorption kinetics of vanadyl etioporphyrins on Dagang (DG) asphaltene in n-pentane solvent was investigated. The FT-ICR MS and C/H/N/O element analysis results indicated that a certain amount of vanadyl porphyrins can be adsorbed by the DG asphaltene, proving the interactions present between vanadium porphyrins and DG asphaltene. The adsorption process is influenced by the dosage of asphaltene (0.010 0 and 0.020 0 g), the concentration of vanadyl porphyrins in n-pentane (10 and 15 μg/mL), and the adsorption temperature (15、20 and 25 ℃). The overall adsorption rates are fitted by the pseudo-first order, pseudo-second order, Elovich, and diffusion kinetic models, which suggests that the adsorption process can be well described by the pseudo-second order equation.
Abstract: A novel basic ionic liquid paired by 1-butyl-3-methyl-morpholine cation and morpholine anion (Im) was synthesized in two steps; the structure of ionic liquid intermediates was characterized by 1H-NMR and FT-IR. The alkaline ionic liquid was obtained through anion exchange and used as catalyst in the synthesis of biodiesel by transesterification. The results showed that the alkaline ionic liquid Im is highly active as a catalyst in the transesterification; under the optimum reaction conditions of 60 ℃, Im amount of 3%, and methanol/oil mol ratio of 6.5：1.0, the content of fatty acid methyl ester (FAME) in the product reaches 95.80% after reaction for 2 h. Moreover, the alkaline ionic liquid exhibits high catalytic stability upon reusage; it remains highly active even after being reused for five times.
Abstract: The hydroisomerization of n-heptane over the Pt/SAPO-11 and Pt/ZSM-22 catalysts prepared by the impregnation methods was systematically investigated in the presence of ethanol. The physicochemical properties, adsorption and reaction behaviors, and active acid sites were studied by X-ray diffraction, N2-adsorption, C2H5OH-TPD and C2H5OH-FTIR techniques. A negative impact of alcohol was observed; the activity and selectivity to isomers decreased with the increase of the ethanol amount. Nevertheless, the effect of ethanol on the hydroisomerization over the Pt/SAPO-11 was weaker than that over the Pt/ZSM-22, showing that Pt/SAPO-11 is more resistant to oxygenated compounds due to the presence of a large amount of P-OH groups in SAPO-11. The effect of ethanol on the isomerization of n-heptane occurs through its dehydration into water over the catalysts.
Abstract: In this research work, two 30%(Co-Mn)/TiO2 catalysts were prepared using sol-gel (catalyst A) and co-precipitation (catalyst B) methods. The activity and selectivity to C2~4 light olefins in Fischer-Tropsch synthesis (FTS) has been studied in a fixed-bed reactor under different operational conditions. These operational conditions were: temperature 220~280 ℃, and total pressure from 0.1~0.6 MPa. The optimum operating conditions were investigated after steady state. As the results shown, the catalyst A was more selective to C2~4 olefins (58.7% in 260 ℃) and catalyst B was more selective to C5+ hydrocarbons. Characterization of both catalysts was carried out by using X-ray diffraction (XRD), scanning electron microscopy (SEM) and N2 adsorption-desorption measurements methods.
Abstract: A series of Fe-Zr catalysts with different Fe2O3/ZrO2 molar ratios were prepared using ZrO(NO3)2·2H2O and Fe(NO3)3·9H2O as raw materials by means of microwave-hydrothermal method. Then,the catalysts were promoted with potassium by impregnation. The samples were characterized by XRD,SEM,TEM and N2 adsorption-desorption methods. The results showed that the catalysts prepared by microwave-hydrothermal method have a narrow particle size distribution,a lower BET specific surface area and a larger pore size compared with the traditional precipitation method. During the subsequent CO hydrogenation,it was shown that the product distribution was significantly improved with the addition of zirconium,and the suitable interaction between Fe-Zr and proper pore size were favorable for inhibiting the methane formation and enhance the olefin selectivity. With decreasing the Fe2O3/ZrO2 molar ratio,the interaction between Fe and Zr was strengthened,and the olefin selectivity and productivity first increased and then decreased. An olefin to paraffin ratio of 4.86 and light olefin productivity of 62.57 g/m3 could be obtained with a Fe2O3/ZrO2 molar ratio of 75：25 under conditions of H2/CO=2,340 ℃,1.5 MPa and 1 000 h-1.
Abstract: ZSM-5/MCM-48 micro/mesoporous composite materials were successfully prepared by using a two-step synthesis route. XRD, N2 adsorption SEM, TEM, FT-IR, and Py-FTIR were used to characterize the effects of the different crystallization time on the structure, surface acidity and reaction performance of methanol to gasoline. The results indicated that, the catalytic mechanism is the surface modification of mesoporous MCM-48 to microporous ZSM-5. Compared with the conventional ZSM-5 based catalyst, it was found that ZSM-5/MCM-48 composite catalyst had excellent low temperature activity and selectivity of gasoline fraction in MTG reaction, and significantly reduced the yield of total aromatic and durene in the oil.
Abstract: Ni-Ce/Al2O3 catalysts with different Ce contents were prepared by wet impregnation method using γ-Al2O3 as support, and their catalytic performance of CO methanation in slurry-bed reactor were evaluated. The catalysts were characterized with XRD, BET, H2-TPR, CO-TPD, and the relationship between the microstructural properties of catalysts and CO methanation in slurry-bed reactor was investigated. The results indicated that the addition of Ce into Ni/Al2O3 catalyst strengthened the interaction between Ni species and the support and enhanced the CO adsorption. With the increase of Ce content, the dispersion of Ni species on support was improved, the particle size of nickel decreased, the specific surface area and the relative content of β-NiO with stronger interaction with support increased firstly and then decreased. The catalytic performance of CO methanation in slurry-bed changed regularly with the increase of Ce content, the conversion of CO and the space-time yield (STY) of CH4 were all increased firstly and then decreased slightly. When the content of Ce reached 4%, the catalyst exhibited the best catalytic performance.
Abstract: Cu-Co spinel oxides with different compositions were prepared for N2O catalytic decomposition in the presence of oxygen. The active catalyst of Cu0.8Co0.2Co2O4 was incipiently impregnated by alkali metal salt solutions to prepare the modified catalysts. These catalysts were characterized by BET, XRD, SEM and XPS techniques, and their catalytic activity for N2O decomposition was tested. The effect of alkali metal species, potassium precursors and potassium loadings on catalytic activity was investigated. It was found that the catalytic activity of Cu0.8Co0.2Co2O4 modified by K2CO3 was much higher than that of bare oxide, while Cs/Cu0.8Co0.2Co2O4 was inferior to Cu0.8Co0.2Co2O4 for N2O decomposition. In the case of K/Cu0.8Co0.2Co2O4 with different potassium precursors, the catalyst activity was largely enhanced by the addition of K2CO3, while the doping of KNO3 and CH3COOK notably depressed the catalytic activity. Over the optimal catalyst of 0.05K/Cu0.8Co0.2Co2O4, 100% and 87.6% conversion of N2O was reached at 400 SymbolpB@ C under the atmosphere of oxygen only and oxygen-steam together, respectively. In addition, K2CO3-modified catalyst in both reaction atmospheres showed higher stability than un-modified catalyst.
Abstract: Atomic XAFS (AXAFS) originates from photoelectron scattering off electrons in bonds on the periphery of the absorber atom, the embedded-atom potential, the interstitial potential and the distribution of the absorber-atom electron density are all found to be important in determining the AXAFS intensity, hence AXAFS can be a very useful probe to monitor changes in the electronic and chemical structure of the absorber atom. In this work, we use AXAFS of Zn element to study the reaction mechanism of the calcined and the reduced adsorbent under different atmospheres, it is showed that hydrogen plays an important role in the desulfurization. In situ AXAFS of Zn element also exhibits the chemical structure evolution of Zn element during desulfurization at 350 ℃ and 3.0 MPa in the atmosphere of H2.
Abstract: The residue fluid catalytic cracking (RFCC) additives containing macropores were prepared with 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) of room temperature ionic liquid modified halloysite as matrix and the USY zeolite as base. X-ray powder diffraction and N2 adsorption-desorption were employed for characterization of the crystallinity and macroporous structure of RFCC additives. The performance of RFCC additives were carried out over a confined fluidized bed fluidized bed (ACE-MODEL R+ MM) with Jinan FCC feedstock and Jinan FCC balance catalyst. It was found that the ionic liquid strongly interacted with the surface hydroxyl of halloysite firstly during the preparation of RFCC additives, and then the strong interaction between ionic liquid and halloysite effectively prevented the binder and USY zeolite to enter the inner of nano-tube of halloysite. At last, the macropores in RFCC additives were produced when the additives were calcinated and the ionic liquid was removed at higher temperature. The resulting macroporous additive exhibited good catalytic cracking activity and high yield of gasoline.
Supervisor：Chinese Academy of Sciences
Sponsors by：Shanxi Institute of Coal Chemistry, Chinese Academy of Sciences Chinese Chemical Society
