Abstract: A series of pyrolysis experiments on Zhundong coal were conducted by using a pressurized tube reactor. Under different pyrolysis temperature, residence time and pressure, the release and transformation behaviors of sodium species with different occurrence modes were investigated by the method of sequential chemical extraction. The results indicate that sodium species are mainly in the form of hydrated ion and albite, and organic forms are quite less. At 500-700℃, water-soluble sodium would be combined with char matrix, forming hydrochloric acid-soluble but water-insoluble sodium. At 700-900℃, soluble sodium could react with minerals such as kaolin, forming insoluble aluminosilicate. At 1 000℃, release of sodium became intense; part of kaolin might be involved into reactions with lime, which inhibited its reactions with soluble sodium. Besides, it is found that release and transformation behaviors of sodium mainly take place at the initial stage of pyrolysis along with release of volatiles and raising pressure has negligible influence on those behaviors.
Abstract: The pyrolysis of Shengli lignite (5-8 mm) under CO2 atmosphere was investigated at the temperature from 400 to 700℃ in a fixed bed reactor, the effect of CO2 on the distribution of gas, solid and liquid phase in the product was analyzed, and the influence mechanism on the char structure under CO2 atmosphere was explored. The results indicate that the yields of tar and water from pyrolysis under CO2 atmosphere are higher than that under N2 atmosphere, with a decrease in char and gas yield. At 400℃ and 500℃, the surface area and pore volume of the char prepared under CO2 atmosphere are nearly the same as that under N2 atmosphere, while at 600 and 700℃, the surface area and pore volume of the char prepared under CO2 atmosphere are higher than that under N2 atmosphere. It maybe attributes to that CO2 can not only promote the release of volatile, but can also react with the active sites in the channels of char. The introduction of CO2 into pyrolysis can increase the aromaticity of char due to the consumption of 3-5 rings aromatic structures. The yields of H2 and CH4 obtained from pyrolysis under CO2 atmosphere are lower than that obtained under N2 atmosphere at 600 and 700℃, and the yield of CO is much higher because of the occurrence of the char-CO2 reaction.
Abstract: Based on two herb residues-herbal tea waste (HTW) and penicillin mycelial waste (PMW), characteristics of NOx precursors during their pyrolysis were investigated in a horizontal tubular reactor with the help of XPS and TGA technologies. Effects of thermal conditions and physicochemical properties of fuels were discussed and compared. The results demonstrate that protein-N is the main nitrogen form for both HTW and PMW, determining the dominance of NH3 among NOx precursors at any operational conditions. Thermal conditions would still change the ratio and total yield by intrinsically influencing their formation pathways. Subsequently, the effects could be sequenced as follows:high temperatures with rapid pyrolysis > high temperatures with slow pyrolysis > low temperatures with rapid pyrolysis ≈ low temperatures with slow pyrolysis. Moreover, at high temperatures with rapid pyrolysis, increase in particle size or decrease in moisture content would result in reduction of total yield by 5%-11% and 4%-6%, respectively. In addition, NH3 yield is produced at low temperatures or slow pyrolysis with sequence of PMW > HTW and vice versa, depending on components in the fuels. Consequently, analyses on nitrogen forms in char and nitrogen distribution indicate that total yield of 20%-45% is observed to be independent of fuel type under typical pyrolysis conditions, which may provide helpful guidance for the clean reutilization of herb residues.
Abstract: Effect of ashing temperature on sintering behavior of ashes from combustion of coal and straw blends was investigated. Blends of a Chinese anthracite, Jincheng coal, and wheat straw were burned at three different temperatures. The resulting ash samples were then subjected to the sintering temperature measurement using a pressure-drop sintering device, morphological and mineralogical characterization with scanning electron microscope (SEM) fitted with X-ray energy dispersive spectroscopy (EDS) and X-ray diffractometry analyzer (XRD), respectively. For the same coal and biomass blends but different ashing temperatures, their sintering temperatures decrease in different extent. In addition, sintering temperatures of the blends under lower ashing temperature are lower than that under the higher ashing temperature. SEM imaging show that the texture of ash samples from lower ashing temperature is irregular, loose and more fibrous. The ashes under higher ashing temperature are mostly in spherical-shape, indicating ash melting has occurred during combustion. The XRD analysis reveals that blends of ash from Jincheng coal and straw under low ashing temperature has low sintering temperature due to more fluxing minerals, like K-containing mineral. The high sintering temperature of the ash blends depends on the Ca-containing minerals like anorthite with high melting temperature.
Abstract: An olivine catalyst was tested in a fixed bed reactor in CO2 reforming of the toluene as a tar model molecule produced during biomass gasification. The olivine catalyst was characterized by XRD, SEM, BET, H2-TPR; and the effects of the operating parameters (reforming reaction temperature and CO2 concentration) and catalyst preparation parameters (calcination temperature and nickel content) on the activity and selectivity for toluene conversion were examined. The results show that the olivine catalyst can increase the toluene conversion and lower the carbon formation. The toluene conversion also increases with the reforming temperature rise. The calcined olivine reaches the highest activity when the calcination temperature is 900℃. The CO2 addition can reduce the carbon formation obviously by 17.0% when the CO2/C7H8 molar ratio is 4. Moreover, the Ni/olivine catalyst has a better performance and the toluene conversation is up to 99.4%, while the carbon formation increases a little bit.
Abstract: A 12-phosphotungstic acid (PTA)-based esterification catalyst was prepared by modifying PTA with 1, 2, 3-trizaole-4, 5-dicarboxylic acid (TDA). The obtained TDA-PTA sample was characterized with XRD, FT-IR, SEM, TG and potentiometric titration techniques, and its catalytic properties for esterification of oleic acid with methanol were studied. In addition, the effects of reaction conditions, including catalyst amount, oleic acid/alcohol molar ratio, reaction time and reaction temperature, on its catalytic performance were investigated. After modification with TDA, although the Keggin structure of PTA is kep and the sample shows strong acidity, the particle morphology changes to regular spheres. In particular, the sample exhibits high catalytic activity and stability in esterification of oleic acid with methanol. The modification of PTA by TDA effectively prevents PTA from dissolving in the reaction mixture, and thus, the TDA-PTA can be recycled at least six runs without severe loss of catalytic activity, showing that it is a good heterogeneous catalyst for esterification.
Abstract: The sulfated zirconia was prepared by directly impregnating ammonium persulphate on the crystalline zirconia and followed by the calcination temperatures of 300-500℃. The structural properties of the catalysts were characterized by X-ray diffraction (XRD), N2 adsorption-desorption, ammonia temperature programmed desorption (NH3-TPD), Fourier transform infrared spectroscopy (FT-IR) and a scanning electron microscope (SEM) equipped with an energy dispersive spectroscope (EDS). The experiment results demonstrated that the catalysts presented the tetragonal structure of zirconia and high crystallinity. The catalyst calcined at 500℃ possessed the highest sulfur content and acidic sites in the catalysts. The catalyst exhibited high catalytic activity in transesterification of soybean oil with methanol. The yield of biodiesel achieved 84.6% because of the preferable super-acid sites on the surface of the catalyst.
Abstract: Conversion of cellulose into 5-hydroxymethylfurfural (5-HMF) catalyzed by SnCl4 in ZnCl2 solution with microwave was studied. The effects of microwave power, cellulose content, concentration of ZnCl2, reaction time and the molar ratio of SnCl4 to cellulose on the yields of 5-HMF were investigated. The results showed that under the optimum reaction condition of 1.0 g cellulose dissolved in 100 mL 70% ZnCl2 solution, the molar ratio of SnCl4 to cellulose of 2:1, the microwave power of 420 W, and the reaction time of 9 min, the yield of 5-HMF reaches 39.4%.
Abstract: A series of molybdenum phosphide (MoP) catalysts for the hydrogenation of acetic acid to ethanol were successfully synthesized and identified by means of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Scanning electron microscope (SEM). The results reveal that MoP2O7 and MoO2 exist on the catalyst surface together with MoP. MoP or the synergistic effects of MoP2O7 and MoO2 species play roles in hydrogenation of acetic acid to ethanol. Phosphating temperature significantly affects the formation and dispersion of phosphide. A low phosphating temperature is not sufficient for the formation of MoP, but a high phosphating temperature leads to the agglomeration of MoP. The catalyst reduced at 650℃ has the highest hydrogenation activity and its P/Mo molar ratio is 1.0.
Abstract: A series of WO3-ZrO2 solid acids were synthesized by calcining the equilibrium adsorbed peroxotungstic acid/hydrated zirconia precursors. The influences of peroxotungstic acid concentration and calcination temperature on the composition, structure and acidity of the obtained solid acids were evaluated by using XRD, UV-vis and NH3-TPD. Pt/WO3-ZrO2 catalysts were prepared by impregnation method and characterized by BET, H2-TPR and H2-TPD. The catalytic performance in the hydroisomerization of n-pentane was investigated. It was found that under the same calcination temperature, both the support acidity and the catalyst surface area first increase and then decrease with the increase of peroxotungstic acid concentration, and are maximized when the peroxotungstic acid concentration reaches 82 mmol W/L. When the peroxotungstic acid possesses the same concentration of 59 mmol W/L, the tetragonal zirconia fraction, support acidity and the catalyst surface area decrease with the increase of calcination temperature. When the peroxotungstic acid concentration and the calcination temperature of the support are 82 mmol W/L and 700℃ respectively, the obtained catalyst shows the best catalytic performance. The yield of isopentane reaches 57.7% under the reaction condition of ambient pressure, 250℃, n(H2)/n(n-C5H12)=3 and WHSV=1.0 h-1.
Abstract: SAPO-11 molecular sieves were treated with different acids and salts and the modified Pt/SAPO-11 catalysts were prepared by loading platinum on the pre-treated SAPO-11. The catalyst samples were characterized with XRF, XRD, N2 adsorption-desorption, SEM, NH3-TPD and pyridine Py-IR to analyze their physicochemical properties. The results showed that the modification of acid and salt did not destroy the structure of SAPO-11, but improved the pore volume, pore size and specific surface area of the catalysts, meanwhile, the acidity and acid amount of the zeolite were also changed obviously. In a fixed-bed reactor, one-step hydrgenation of Jatropha curcas oil to iso-alkanes over modified Pt/SAPO-11 catalyst was carried out. Combined with catalyst characterization results, it was concluded that those parameters, such as particle size, specific surface area, pore diameter, acidity and acid amount, would affect the activity and product distribution of the catalysts. Among these modified catalysts, it is found that the Pt/SAPO-11 catalyst treated with 0.5 mol/L citric acid solution exhibited an excellent catalytic performance in one-step hydrogenation of Jatropha curcas oil, owing to its appropriate pore size, acidity, B acid and L acid distribution. The yield of bio-jet fuel components (C8-16) was 32.47% and the selectivity of isoparaffins was 53.13%.
Abstract: A mesoporous carbon containing tungsten was prepared using Na2WO4 and EDTA-2Na as the source of tungsten and carbon and characterized by XRD, FT-IR, SEM and BET. The results show that the tungsten oxide with crystal water (WO3·H2O) is formed on the surface of mesoporous carbon. Compared with pure mesoporous carbon, the total surface area of mesoporous carbon containing tungsten decreases. An extraction-catalytic oxidation desulfurization (ECODS) system was constructed using mesoporous carbon containing tungsten as catalyst, H2O2 as oxidant and ionic liquids (ILs) 1-butyl-3-methyl imidazolium tetrafluoroborate ([BMIM] [BF4]) as extraction agent. The effects of tungsten oxide loading, reaction temperature, the amount of H2O2, the amount of catalyst and ILs dosage and different types of sulfur compounds on the removal of DBT was studied. Under the optimal conditions, the removal rate of DBT reaches 98.6% for DBT, 65.6% for 4, 6-DMDBT, 61.2% for BT, 57.8% for TH and 64.3% for actual gasoline, respectively. The desulfurization rate is slightly decreased when the catalyst is reused five times.
Abstract: CuO-CeO2 monolithic catalysts supported on SiO2-Al2O3 modified glass-fiber honeycomb were prepared via co-impregnation method and their performance in the oxidation of volatile organic compounds (VOCs) such as ethyl acetate, isopropanol and toluene was evaluated. Various techniques such as N2 sorption, X-ray powder diffraction (XRD), hydrogen-temperature programmed reduction (H2-TPR), ammonia-temperature programmed desorption (NH3-TPD) and chemisorption of VOCs were employed to characterize the catalysts. The results show that the copper oxide species are highly dispersed on the CuO-CeO2 based catalysts; moreover, the size of CeO2 nanoparticles increases with the decrease of copper/ceria molar ratio. The addition of ceria oxide can evidently increase the amount of total acid sites, especially the Lewis ones, which can enhance the adsorption capacity of ethyl acetate and isopropanaol and promote the oxidation of ethyl acetate and isopropanaol. In the case of toluene combustion, the addition of large amount of CeO2 may decrease the reducibility and oxygen activation capability; as a result, it contributes little to the adsorption of toluene, resulting in a low activity in the oxidation of toluene. The catalytic activity is related both to the reactivity of surface oxygen and to the adsorption capacity of the catalyst towards VOC molecules, which are determined by the complex interactions among copper, cerium oxide and the support.
Abstract: With reduced graphene oxide (RGO) as the precursor, Fe3O4/RGO composites were synthesized via a hydrothermal method combined with annealing treatment; the crystalline phase, microstructure and component of Fe3O4/RGO composites were characterized by XRD, SEM, TEM and Raman spectra. As a new type of lithium battery electrode materials, their electrochemical performance and the corresponding performance enhanced mechanism were investigated by the CV and EIS tests. The results indicate that high loading Fe3O4/RGO anodes after charge-discharge 60 cycles show high reversible capacities of 709 mAh/g at 200 mA/g and 479 mAh/g at 600 mA/g, with a very good rate performance. Compared with the Fe3O4 electrodes, Fe3O4/RGO electrodes exhibit better electrochemical performance, which is associated with a synergy between the stable RGO matrix and its good conductivity; such a nano-sized configuration may not only facilitate the electron conduction but also help to maintain the structural integrity of active materials.
Abstract: A microbial fuel cell system was built by using the mixed solution of K3[Fe (CN)6] and NaCl as catholyte, acclimated sediment of an artificial lake as the source of microbial species, and streptomycin wastewater as anolyte; the effect of co-substrate addition on the purification effect and electricity generation ability of the microbial fuel cell was investigated. The results show that the electricity generation ability and wastewater treatment effect of microbial fuel cell with streptomycin wastewater as anolyte are quite poor and deteriorate even further with the increase of the streptomycin concentration. However, the electricity generation ability and wastewater treatment effect of the microbial fuel cell can be significantly improved by adding glucose as a co-substrate to the anode streptomycin wastewater. In case without the co-substrate, the COD removal rate is only 52% when the concentration of streptomycin is 50 mg/L, with a steady electric current density of 25 mA/m2 and a steady output voltage of 4.72 mV; by adding the co-substrate, the COD removal rate reaches 92%, with a steady electric current density of 300 mA/m2 and a steady output voltage of 54 mV.
Abstract: Cerium modified semi coke adsorbent (Ce/SC) was prepared by impregnation method and a bench-scale fixed bed reactor was used to study the effect of H2O vapor and α-Fe2O3 on elemental mercury removal efficiency over Ce/SC. Characterizations of X-ray powder diffraction (XRD), Hydrogen temperature programmed reduction (H2-TPR), and X-ray photoelectron spectroscopy (XPS) were conducted to investigate the mechanism of elemental mercury removal.The adsorption results showed that H2O had a negative effect on the oxidation activity of the adsorbent. H2O can be dissociated on the surface of CeO2 with partial lattice oxygen transformation into Ce-OH functional groups which led to the decrease of its oxidation activity and thus resulted in the inhibitory effect of mercury removal efficiency. The addition of α-Fe2O3 had no significant effect on mercury removal over Ce/SC. The mercury removal efficiency of Ce/SC was decreased when the water vapor and α-Fe2O3 existed simultaneously. However, the decrease rate was much lower than that of water vapor conditions alone mainly due to the interaction between water vapor and α-Fe2O3 increased the content of the surface chemical adsorbed oxygen and thus the oxidation activity and elemental mercury removal performance of Fe2O3were promoted.
Abstract: Modes of iodine occurrence in 4 Chinese anthracites and the combustion residues obtained at each temperature were extracted with sequential chemical extraction. The coal combustion was simulated with a tube furnace, the effects and mechanisms of heating temperature, heating time, O2 flow rate and water vapor on iodine release and transformation behavior during anthracite combustion were investigated. The results showed iodine in anthracites can present typically in three main modes of occurrence:organic matter-bound, Fe-Mn oxide-bound and water-soluble form. Temperature had a pronounced effect on iodine release and transformation. Iodine release increased with the increase of temperature, and 500-900℃ was a main stage for iodine release. Before 700℃, some forms of iodine which include water-soluble, ion-exchangeable and organic matter-bound iodine can be almost emitted completely and partly transformed into the carbonate-bound, Fe-Mn oxide-bound and residue-bound iodine. The Fe-Mn oxide-bound iodine may be mainly emitted in 700-900℃, and the residue-bound iodine was emitted partly before 1 100℃.Moreover, the iodine release from anthracite increased with the increase of heating time and O2 flow rate, and water vapor can obviously promote the iodine release. 93.8%-95.9% of iodine may be emitted in the form of HI and I2 at the given experimental condition of 1 100℃, water vapor access, O2 flow rate of 120 mL/min and combustion time of 20 min.
Supervisor：Chinese Academy of Sciences
Sponsors by：Shanxi Institute of Coal Chemistry, Chinese Academy of Sciences Chinese Chemical Society
