Abstract: The co-pyrolysis and co-liquefaction behaviors of Shenfu coal (SC) and rice straw (RS) were investigated. The synergistic interaction between SC and RS was examined by comparing the pyrolysis and liquefaction performances of each material with those of their mixtures. TG analysis suggests that the pyrolysis temperature of RS is low. Pyrolysis of RS can form free radicals at lower temperature, which can promote the pyrolysis of coal when it is co-pyrolyzed with SC, resulting in larger weight losses of their mixture compared to the arithmetic mean values from individual pyrolysis of SC and RS. Co-liquefaction results indicate that there exists an obvious synergistic effect between SC and RS, which is depend on liquefaction conditions. At high liquefaction temperature and long reaction time, the synergistic effect decreases because of the increased pyrolysis rate and lack of hydrogen donating ability, resulting in the increased retrogressive condensation reactions. The largest synergistic effect of SC and RS is obtained at 400℃ and 60min with 50% blending of RS. The liquefaction conversion and hexane soluble fraction of the co-liquefaction at this optimal condition are higher of 14.8% and 9.7% than the corresponding arithmetic mean values from the individual liquefaction of SC and RS respectively.
Abstract: Effects of feedstock on the co-pyrolysis of biomass and coal were investigated in a free fall reactor at 500℃~700℃ with biomass blending ratio of 0~100%(mass ratio). The selected coal samples were Dayan brown coal (DY) and Tiefa bituminous coal (TF), and the biomass samples were agricultural residues legume straw (LS) and woody residues pine sawdust (SD). The results indicate that the synergy can occur even in a short gas residence time during the co-pyrolysis of biomass and coal in a free-fall reactor. The product yields and the CO2 reactivity of char from the co-pyrolysis are greatly influenced by the type of feedstock. The synergy in the presence of LS with high holocellulose and ash content is more significant than that in the presence of SD. The liquid yield of high rank TF co-pyrolysis is higher than that of low rank DY coal. The char reactivity can be improved by the co-pyrolysis at specific conditions. The co-pyrolysis in presence of DY can improve the reactivity of the produced char.
Abstract: LaMnAl11O19 catalysts were prepared by co-precipitation method and characterized with XRD, BET and XPS. The conversion of NH3 at the conditions of catalytic combustion and homogeneous combustion were studied by combustion of simulated biomass gasification gas and NH3 oxidation, respectively. Moreover, the NH3 adsorption and oxidation on the surfaces of the catalyst samples were examined by in-situ DRIFT experiments. It was found that calcination of the percursors at 1200℃ led to the formation of a final monophasic materials with MP structure and high surface area, while the Mn ions were either divalent or trivalent. Under homogeneous combustion condition, NH3 at simulated biomass gasification gas started to react at 500℃, then NO was formed. Under catalytic combustion condition, the curves of NH3 oxidation with and without addition of simulated gasification gas showed no obvious differences. NH3 started to react at 310℃, and NO exhibited higher concentration in the temperature range of 350℃~800℃. However, NO2 was generated at higher temperature within a narrow temperature range. The concentration of N2O during the reaction was less than 10 ×10-6. More than 40% of the NH3 converted to NO during the experiments. The results of in-situ DRIFT indicated that the reaction of ammonia conversion followed the imide (-NH) mechanism, that is, the ammonia adsorbed on the catalyst surface was decomposed to -NH firstly, then the -NH reacted with atomic oxygen (O) to further form nitroxyl (HNO) and N2 or nitrous oxide (N2O), or -NH reacted with molecular O2 to produce nitric oxide (NO) directly.
Abstract: Three biofuels, cornstalk, wheat straw and sawdust were combusted purely and co-combusted as given mixing ratio. The specific resistance (R) of ashes was measured by DR type dust specific resistance testing instrument and chemical compositions were detected by Atomic Absorption Spectrometry (AAS). The results show that the R values of ashes from pure biomass combustion are between 108Ω·cm and 1010Ω·cm, which belongs to medium specific resistance. The R values of ashes from co-combustion are between 108Ω·cm and 1012Ω·cm. Regarding ashes from burning cornstalk and coal, mixing ratio (Rt) brings little effect on R. As for ashes from combustion of wheat and coal, when the measuring temperatures are lower than 110℃, the more the Rt is, the lower the R is. The rule is inverse when the temperatures are higher than 110℃. Co-combustion alters the fuel characteristics of burning and fusing, changes the physical characteristics and chemical components as well as contents, resulting in the specific resistance differences between ashes from co-combustion and pure combustion.
Abstract: The chemical compositions and structures of different kinds of bio-oils were compared by gas chromatography/mass spectrometry (GC/MS) and Nuclear Magnetic Resonance Spectroscopy (NMR). It was shown that contents of main kinds of compounds were significantly different in different kinds of bio-oils because of the discrepancies of chemical compositions of biomasses. Bio-oils from corncob and pine contained more aromatics, and that from straw had more anhydrosugars, aldehydes and ketones, while that from bagasse contained more organic acids, aldehydes and ketones. 13C-NMR spectra revealed that bio-oil from straw contained the most alkyl carbon and carbonyl carbons, while that from pine and bagasse contained the most aromatic carbon and carboxylic carbon, respectively. From the 1H-NMR spectra, it was observed that the most alkyl hydrogen and sugar hydroxyl hydrogen were found in bio-oil from bagasse and straw, respectively. While the most phenolic hydroxyl hydrogen and aromatic hydrogen both existed in the bio-oil from pine. The discrepancies of functional groups of different kinds of bio-oils resulted in the differences of physical properties.
Abstract: The preparation condition of silica gel column chromatography- K2CO3 loaded solid-base catalyst was studied.The catalyst was characterized by means of XRD, FT-IR and SEM. The experimental results showed that part of K2CO3 generated KHCO3 due to absorbing CO2 in the air. K2CO3 and KHCO3 dispersed on the silicon surface could enhance the catalytic activity. At the optimum conditions：catalyst preparation temperature:120℃, amount of catalyst in the fuel oil: 5%, ratio of alcohol to oil: 12∶1, reaction temperature: 70℃and reaction time: 2h, the biodiesel yield could reach up to 95.2%.
Abstract: Carbon deposition caused by reforming in micro-combustor brings catalyst deactivation and channel snarl-up. The technology of methane wet-air autothermal reforming is presented to realize methane last, steady-state combustion and to reduce carbon deposition. The effects for carbon deposition below 973K are discussed by thermodynamic analysis at 0.1MPa in this paper. Results show that temperature, air-methane ratio and steam-methane ratio contribute a lot to the carbon deposition. In micro-combustor, carbon deposition increases with temperature increasing first, then decreases; it is beneficial to reduce carbon deposition as well as to produce hydrogen with air and steam increase under lean oxygen; at the same time, autothermal reforming compared with non-steam system is superior on reducing carbon deposition in micro-combustor. When methane mass flow is 6.6g/h, air-methane ratio and steam-methane ratio are respectively 2 and 1 in micro-combustor, the carbon deposition temperature range is at 680K~850K. The largest mass fraction of carbon deposition is 0.66% and occurred at 785K, also the methane conversion rate and the mass fraction of hydrogen are approximately 53.43% and 2.37%; and that, requirements of air-methane ratio and steam-methane ratio to eliminate the carbon deposition are about 2.4 and 1.1 respectively.
Abstract: Heavy oil hydrotreating catalysts NiW/CTS were prepared by iso-volumetric impregnation method, where the catalyst support (CTS) was obtained from in-situ growth of TiO2-SiO2 oxides covering on the particles of Y zeolites. NiW/CTS catalysts were then modified by surface impregnation of phosphoric acid or co-impregnation of phosphoric acid with metal precursors. The effect of phosphoric acid modification on the physic-chemical properties and hydrotreating performance of the NiW/CTS catalysts were investigated. The results showed that the phosphoric modification causes a decrease of acid amount in NiW/CTS; surface impregnation reduces Lewis acid sites, while co-impregnation enhances the Lewis acid sites. The presence of phosphoric acid in NiW/CTS can weaken the interaction between the support and metal components and improve the dispersion of active metals on the catalyst surface. The co-impregnation method can promote the formation of metal oxide precursor with high hydrogenation activity; therefore, NiW/CTS catalysts modified by phosphoric acid co-impregnation exhibits better performance in hydro-desulfurization, hydro-denitrogenation and hydro-dearomatics.
Abstract: Oxidative desulfurization (ODS) of benzothiophene (BT), dibenzothiophene (DBT) and 4, 6-dimethyl dibenzothiophene (DMDBT) in model light oil was investigated with different oxidants over Ti-MWW catalyst. The results indicated that tert-butyl hydroperoxide (TBHP) exhibits higher reactivity with these organic sulfur-containing compounds than hydogen peroxide. In the presence of TBHP, the reactivity of these sulfur-containing compounds over Ti-MWW catalyst is in the order of DBT > DMDBT > BT, which is determined by the electron density of sulfur atom in thiophene ring as well as the steric hindrance of sulfur compounds. ODS of a commercial diesel oil was also investigated over the Ti-MWW/TBHP system. The sulfur compounds in the commercial diesel oil can be efficiently oxidized to corresponding sulfone under mild reaction conditions; by oxidation and extraction twice, the sulfur content in the commercial diesel oil is decreased from 1015μg/mL to 11μg/ mL and the sulfur removal reaches 99%.
Abstract: Properties of activated coke (AC) are very important for preparing the V2O5/AC catalysts of high activity for flue gas SO2 removal. Four ACs as the catalyst carrier are studied in this work, and the experiments include the measurements of SO2 removal activity, oxidation activity and pore structure. The ACs are found to have few sites of high oxidation activity. The loading V2O5 leads to a high oxidation activity and much increased SO2 removal activity. The well developed pore structure of the ACs is attributed to the high distribution of V2O5 and to the high oxidation activity. The SO2 removal activity of V2O5/AC mainly depends on the AC's pore structure instead of its oxidation activity.
Abstract: A series of TiO2 supported manganese oxide catalysts, MnOx/TiO2 , were prepared by wet-impregnation method for the low temperature selective catalytic reduction (SCR) of NO with ammonia. WO3 with different loadings was added to MnOx /TiO2 samples to investigate its possible influence on the catalytic activity of MnOx /TiO2 by using several characterization techniques including BET surface area, laser Raman spectroscopy (LRS), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction(XRD). The research shows that minute addition of 5% WO3 raises the catalytic performance of MnOx /TiO2 catalyst effectively by expanding the carrier’s surface area, improving its thermal resistance, increasing surface Brnsted acids and NH3 adsorption capacity, and broadening the temperature window of SCR reaction. The MnOx -WO3/TiO2 shows better SCR activity than WO3- MnOx /TiO2 in terms of impregnation sequence. The adsorption peaks of NH3 on surface of catalysts will be weakened or lost with temperature increasing, and the denitration reactivity curve of catalysts shows a maximum with the increase of temperature.
Abstract: ZSM-5/SAPO-5 composite molecular sieves of core/shell structure were synthesized by embedding method and characterized by XRD and SEM; the effect of gel composition on their structure and morphology was investigated. The composite molecular sieves synthesized exhibit a binary structure with ZSM-5 as core and SAPO-5 as shell. The crystallinity and particle morphology of the composite molecular sieves are influenced by seed crystal and solvent used during synthesis. Through adding seed crystal, the crystallinity of the composite molecular sieves increases and the particles are mainly in elliptic morphology; by using a mixture of water and alcohols as solvent during synthesis, the particle morphology is mainly of sphericity, while the crystallization rate as well as the maximum crystallinity of the composite molecular sieves decreases.
Abstract: Active carbon supported Au-Pt catalyst (Au-Pt/C) with different Pt/Au atom ratios was prepared and the effect of Pt/Au atom ratio on the electrocatalytic performance of Au-Pt/C in direct formic acid fuel cell (DFAFC) like the oxygen reduction ability and tolerance to formic acid was investigated. Comparing with Au/C catalyst, the Au-Pt/C catalyst exhibits better electrocatalytic performance towards the reduction of oxygen. With the increase of Pt/Au atom ratio from 0/50 to 2/48, Au-Pt/C catalyst shows excellent electrocatalytic ability and formic acid tolerance. However, when Pt/Au atom ratio is further raised to 3/47, the formic acid tolerance of Au-Pt/C is decreased. As a result, Au-Pt/C catalyst with a Pt/Au atom ratio of 2/48 is appropriate as the cathodic catalyst in DFAFC.
Abstract: The air gasification characteristics of five different sewage sludges were carried out in an external heated downdraft fixed-bed. The results show that the higher gasification temperature can improve the quality of product gases, and the contents of CO, CH4, H2 and the lower heating value (LHV) of the gases decrease with the increase of air flux. Anaerobic digestion process of the sewage sludge reduces the quality of the gases which is also affected by wastewater treatment of the sludges. The contents of CO, CO2 in the gases from the undigested sludge of continuous SBR process are the highest, and that of H2, CH4, CmHn are the least. There are the highest contents of H2 and CmHn in the gas from the undigested sludge of activated sludge process. The gases from the undigested sludge of A2/O process contain the least contents of CO, CO2 and the highest CH4 content. The LHV of the gases from the three sludges increase in turn.
Supervisor：Chinese Academy of Sciences
Sponsors by：Shanxi Institute of Coal Chemistry, Chinese Academy of Sciences Chinese Chemical Society
