Abstract: The oil shales from Maoming (Guangdong province) and Fushun (Liaoning province) were selected for hydrochloric acid pickling. Dichloromethane and tetrahydrofuran were used to extract oil shales before and after acid pickling. The extracts were characterized and the leaching behavior of small molecules was concluded using GC-MS analysis. The results show that the treatment by hydrochloric acid pickling can improve the extraction yield. The compositions of alkanes in extracts are less influenced by the hydrochloric acid pickling than the oxygenated small molecules. The relative content of extracts or the quantity of detectable compounds changes somewhat by comparing the extracts of the same sample before and after acid pickling. The majority extracts are alkanes and oxygenated small molecules compounds from extraction with dichloromethane and tetrahydrofuran, respectively.
Abstract: Considering the form of sodium existing in coal, series of water washing and hydrothermal treatments were used to remove alkali metals from a high sodium coal from Wucaiwan. The variation of combustion characteristics of coal after pretreatment was investigated. The results show that the sodium in the coal mainly exists as water-soluble form. The Na removal ratio by water washing treatment does not reach the expectation with the characteristics of time consuming and high water consumption. The hydrothermal treatment is effective in sodium removal as high as 90.5%, and Na2O content in the ash decreases to 0.7% which belongs to the scope of low sodium level in coal ash. The burning curves of coal samples after hydrothermal treatment move to the low temperature zone, and the combustion characteristics is improved compared with raw coal.
Abstract: On the basis of 120 coal ash samples, a CSBP model based on BP(Back Propagation) Neural Network optimized by Cuckoo Search (CS) was proposed for predicting the ash deformation temperature of single coals, coals mixed with addictives and mixed coals. The thirteen chemical composition parameters and combined parameters were employed as inputs, and the ash deformation temperature was used as output of the CSBP model. The results show that whether single coal, coal mixed with additives or mixed coals, CSBP model has a better performance compared with BP model and the average relative errors are reduced to 3.11%, 4.08% and 4.22%, respectively. In addition, comparing the prediction results of three kinds of samples, both the CSBP model and BP model have higher prediction errors for coals mixed with addictives and mixed coals more than that for single coals.
Abstract: The alcoholysis of pine sawdust with acidified ethylene glycol (EG) as solvent was investigated; the influence of reaction temperature and time on the conversion of pine sawdust was examined. The alcoholysis residual was characterized by thermogravimetry (TG), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM) and X-ray diffraction (XRD), whereas the composition and properties of hexane insoluble components (HIS) and hexane soluble ones (HS) were determined by FT-IR and gas chromatography-mass spectrometry (GC-MS). The results showed that the conversion of pine sawdust reaches a maximum of 95.3% at 160 ℃ after reaction for 90 min. By the alcoholysis, the amorphous components of cellulose and lignin were decomposed and the surface structure of alcoholysis residual is destructed. The hexane insoluble components are composed of compounds with oxygen-bearing functional groups such as hydroxyl, methoxyl and ether, whereas the hexane soluble components consist of mainly phthalic acid esters, methyl stearate, 2-methyl propyl caproate, 2-methyl propionic acid, polyethylene glycol and unreacted EG. The esterification of EG with carboxylic acid, derived from pine sawdust, can improve the stability of liquid product and promote the alcoholysis of pine sawdust, whereas the self-condensation of EG, forming polyethylene glycol, may increase the consumption of EG.
Abstract: A series of Ru/Ce0.8Zr0.2O2 catalysts were prepared by the impregnation method with Ce0.8Zr0.2O2 homoprecipitated and calcined at different temperatures as supports. The supports and the catalysts were characterized with TG-DSC, BET and H2-TPR techniques. It was shown that the Ce0.8Zr0.2O2 calcined at 500 ℃ formed Ce-Zr solid solution and had a proper surface area and pore opening and a weak interaction with Ru species, leading to a significant increase in the catalytic activity. A suitable reduction methods promoted distribution of active species. The Ru/Ce0.8Zr0.2O2 prepared with the Ce0.8Zr0.2O2 calcined at 500 ℃ showed high activity after calcination at 400 ℃ and successive reduction with H2N·NH2·H2O and H2. It gave a H2 conversion of 93.57%, approaching to the equilibrium value under the conditions of 290 ℃, 0.1 MPa, 10 000 h-1 and H2/CO2 mol ratio of 3.5.
Abstract: LiMn2O4 prepared by high temperature solid state reaction, pechini, and citric acid coordination methods was applied in selective catalytic reduction (SCR) of NO with NH3. MnO2 prepared by high temperature solid state reaction method and the activity was tested as a comparsion. The catalysts were characterized by N2 adsorption-desorption, scanning electron microscopy, X-ray diffraction, H2 temperature-programmed reduction, NH3 temperature-programmed desorption, NO temperature-programmed desorption, and X-ray photoelectron spectroscopy. The results showed that high-temperature activity of SCR were improved after the introduction of Li into MnO2. NO conversion on the LiMn2O4 prepared by pechini method was above 90% in the range of 130~260 ℃; NO conversion on the LiMn2O4 by high temperature solid state reaction method could be kept above 90% in the range of 90~310 ℃; while the temperature window of MnO2 was only 140~280 ℃. Compared with MnO2, LiMn2O4 crystal structure not only keeps more manganese cations at a relatively low valence of Mn3+, but also adjusts surface active oxygen. Meanwhile, the existence of Li adjusts surface-acid sites of LiMn2O4, thus alleviates the unselective oxidation of NH3 in the high temperature, broadens the operating temperature window of NH3-SCR reaction, and improves the catalyst tolerance of SO2.
Abstract: V2O5-WO3/TiO2 catalyst for the selective catalytic reduction of NOx with NH3 (NH3-SCR) was prepared through wet impregnation and characterized by XPS, Raman spectra, H2-TPR, NH3-TPD, NH3-DRIFT, XRD and physical adsorption. The effect of the pH value of vanadium precursor solution on the catalytic performance of V2O5-WO3/TiO2 in the low temperature NH3-SCR of NOx was investigated to optimize the preparation conditions. The results indicated that with the enhancement of precursor solution acidity, more polymeric vanadium species are formed on the catalyst surface; meanwhile, the ratio of V4+(3+)/V5+, surface acidity, and quantity of active sites are increased, whereas the de-NOx performance of the V2O5-WO3/TiO2 catalyst is largely improved. As a result, a V2O5-WO3/TiO2 catalyst with high performance in de-NOx through NH3-SCR can be obtained by enhancing the precursor solution acidity in the preparation process.
Abstract: A series of MgxFe1-xFe2O4 spinel oxides were prepared and characterized by means of nitrogen physisorption, X-ray diffraction (XRD) and temperature-programmed reduction of hydrogen (H2-TPR). The effect of composition, calcination temperature, and potassium doping on the catalytic activity of the Mg-Fe mixed oxides in N2O decomposition was investigated. The results indicated that the Mg0.6Fe0.4Fe2O4 catalyst calcined at 500 ℃ exhibits highest activity in N2O decomposition. Unexpectedly, the catalyst activity is depressed by the addition of potassium, as the potassium doping may inhibit the reduction of surface iron oxides and reduce the surface area of K-modified catalysts. Long-term tests at 500 ℃ for 10 h also illustrate that Mg0.6Fe0.4Fe2O4 is superior to FeOx catalyst either in the oxygen-alone or in the oxygen-steam concomitant atmosphere.
Abstract: NO reduction by propane over iron was experimentally investigated in a one-dimensional temperature-programmed ceramic tubular reactor at 300~1 100 ℃ in N2 and simulated flue gas atmospheres. The NO reduction efficiencies by C3H8 over iron were compared to that by methane. The results show that propane can effectively reduce NO to N2 over metallic iron. In N2 atmosphere, the NO reduction efficiency by propane over metallic iron is higher than that by methane at 500~900 ℃. More than 95% of NO is reduced by propane over metallic iron when the temperature is above 900 ℃, which is very close to that by methane. In simulated flue gas atmosphere, when the excessive air ratio is lower than 1.0, NO reduction by propane over iron exceeds 90% when the temperature is above 900 ℃. There is little difference in NO reduction whether there is a burnout for propane. At same conditions, NO reduction by propane over iron is higher than that by methane. The effect of SO2 on NO reduction by propane over iron is rather small and can be ignored.
Abstract: The adsorption of NO, O2 molecules on the surface of activated carbon fibers (ACFs) were comprehensively investigated using a simplified zigzag model based on density functional theory. The ACFs model, products, stable intermediates were optimized at B3LYP/6-31G(d) level and the catalytic oxidation mechanism of NO over ACFs surface was proposed. The results revealed that O2 molecules are adsorbed on the ACFs surface, forming two simiquinones (C-O), and then the adsorbed NO(C-NO) is oxidized to -NO2 by the simiquinones. On the other hand, the active oxygen atom (O*), derived from free O2 through catalytic process on the carbon surface, reacts with the adsorbed NO, forming -NO2. However, O2 adsorption is more thermodynamically favorable than NO. Based on statistical thermodynamic analysis, the transformation of NO to NO2 was mainly attributed to the reaction between C-NO and O* generated from the free O2 in atmosphere.
Abstract: Cu(I)Y, Ce(IV)-Y and Cu(I)-Ce(IV)-Y adsorbents were successfully prepared by liquid-phase ion-exchange of Y zeolites with combined Cu and Ce ions. The adsorbents were characterized by means of X-ray diffraction (XRD) and N2-adsorption specific surface area measurements (BET). The effect of preparation conditions on the adsorptive desulfurization properties over Cu(I)-Ce(IV)-Y were studied by a static desulfurization method. The breakthrough sulfur capacities of the adsorbents were studied in a fixed-bed reactor system. Meanwhile, adsorptive desulfurization selectivities of the adsorbents were studied through model fuels, which made up of 1-octane solution of benzothiophene and thiophene, then respectively mixed with a certain amount of toluene, cyclohexene or pyridine. The results indicate that the optimum preparation conditions of Cu(I)-Ce(IV)-Y is ion-exchange time of 48 h, Cu/Ce molar ratio of 1, and calcination temperature of 550 ℃. Cu(I)-Ce(IV)-Y adsorbent exhibited the best desulfurization performance with model fuels, which contain a certain amount of toluene and cyclohexene. The effect of toluene, cyclohexene and pyridine at the same concentration, on the metal ion-exchanged Y zeolites for sulfur removal is in the order: pyridine > cyclohexene > toluene. The introduction of Cu+ can improve the desulfurization activity of adsorbent, while the introduction of Ce4+ can improve the selectivity of adsorbent. The synergistic effect of Cu+ and Ce4+ contribute to Cu(I)-Ce(IV)-Y not only has the high sulfur adsorption capacity but also has the ability of resistance to aromatics and olefins.
Abstract: Binuclear cobalt phthalocyanine was synthesized by microwave method and characterized by infrared spectroscopy, UV-visible spectroscopy and thermogravimetry; its catalytic performance in the oxidative desulfurization of dibenzothiophene (DBT) was investigated. The results showed that the binuclear cobalt phthalocyanine exhibits the highest activity among five catalysts; over it, with the catalyst amount of 0.01 g(cat)/5 mL and air flow rate of 80 mL/min, the sulfur removal rate reaches 97.17% after reaction at 40 ℃ for 1 h. The product of DBT oxidation is DBTO2, as verified by the FT-IR and mass spectrometry. The catalytic performance in the oxidation of aromatics and olefins was also investigated, which illustrates that current process using binuclear cobalt phthalocyanine as the catalyst has little influence on the quality of the oil product. Moreover, the catalyst can be reused for 5 times without significant decrease of its oxidation activity.
Abstract: Catalysts for hydroisodewaxing were prepared by SAPO-11 zeolite instead of ZSM-5 zeolite with nickel and tungsten as metal components. The catalysts were characterized by using XRD, BET and Py-IR. Using Changqing straight-run diesel oil as raw material, we evaluated the hydroisoderwaxing performance of the NiW/SAPO-11 catalysts prepared by different methods. The catalytic performance evaluation was performed on a pressurized fixed-bed microreactor. The result shows that the NiW/SAPO-11 catalyst prepared by mixing-kneading Ni first and then impregnating W active component has better hydroisodewaxing performance. At the reaction conditions of 340 ℃, 4.0 MPa, LHSV 1.0 h-1 and hydrogen to oil volume ratio of 500:1, the freezing point of the diesel oil was decreased from 0 ℃ to -28 ℃, and the diesel yield was as high as 96.0%.
Abstract: For treatment of restaurant wastewater, an experimental system of microbial fuel cell was set up, and the power generation and wastewater purification performance of microbial fuel cell system were studied. Firstly, Fe(NO3)3 solution was used as the catholyte to prove the feasibility of wastewater biodegradation and simultaneous electricity generation from restaurant wastewater. Then, NaCl solution and K3[FE(CN)6] solution are respectively used as the catholyte to conduct contrastive experiments, for studying the effect of power generation performance and wastewater purification of microbial fuel cell system in different operating environment. The results showed that the COD removal efficiency of NaCl solution and K3[FE(CN)6] solution were 30% and 22% respectively, whose average current density were 5.6 mA/m2 and 5.2 mA/m2. In the case that the wastewater dilution ratio was 2:1 and the concentration of NaCl solution was 0.4 mol/L, the generating ability and the purifying effect of the microbial fuel cell achieved the best state, whose steady current density reached at 8.8 mA/m2 and the COD removal efficiency was 33.3%.
Abstract: In order to research catalytic performance of CDPFs (catalyzed diesel particulate filters) loaded different catalysts, CDPF samples were evaluated through gas flow reactor and full-scale CDPFs tests were conducted in diesel engine bench based on AVL-SESAM(System for emission sampling and measurement) FT-IR. The results show that: the light-off temperature of CO and C3H8 decrease in turn as content of the precious metals increase. The light-off temperatures of CDPFs loaded same proportion of noble metals approximately shows linear dependence, while the difference of light-off temperature may result from different content of same proportion of noble metals. At high temperature condition, synergistic effects of content, proportion, valence state of noble metals and gaseous emission concentrations play obvious role on light-off performance of C3H8. In diesel engine bench test, full-scale CDPFs present lower light-off temperature of CO and THC. Within moderate inlet temperatures, increased Pt aids in oxidization of NO, which is speculated that PdO would help to oxidize NO. The existence of Pd may intensify thermal stability of the catalyst. The oxidized process of NO is inhibited by NO2. Meanwhile O2 concentration in the diesel exhaust also affects oxidization of NO. Higher Pd content in Al2O3 coating increase production of nitrate. With combination of Pt/Pd/Rh, the CDPF loaded lower Pd adsorbs much more SO2 on the catalysts. However, as the temperature increases, CeO2 promotes desorption of SO2 on the catalysts, which leads to the sulfur tolerance of the CDPF.
Supervisor：Chinese Academy of Sciences
Sponsors by：Shanxi Institute of Coal Chemistry, Chinese Academy of Sciences Chinese Chemical Society
