Abstract: The effect of preheating treatment (140-230 ℃) on the oxygen migration rule of Hulunbuir lignite which is pyrolyzed at 650 ℃ has been discussed by using the proximate and ultimate analyses, the Fourier transform-infrared spectroscopy, and the gas chromatography-mass spectrometry analysis. Results show that the amount of oxygen migrated to the pyrolysis water and semi-coke is decreased by 7.55% and 1.43%, respectively due to the effect of preheating at 200 ℃. Furthermore, the amount of oxygen transferred to tar and gas is increased by 6.66% and 1.61% respectively, and phenolic oxygen in tar is getting doubled. The decrease of hydrogen bonding and the increase of phenolic compounds are noted as the result of preheating process of lignite, as evidenced by in-situ infrared diffuse reflectance spectroscopy, this could be due to the dissociation of OH…π, OH…N bonds. Hydroxyl self-association hydrogen bonds have also broken down and transformed during the preheating process with the formation of free OH·, which result in the increase of phenol and cresol contents.
Abstract: Studying the evolution and transformation of different forms of nitrogen in pyrolysis under water vapor atmosphere is conducive to control formation of nitrogen oxides. X-ray photoelectron spectroscopy (XPS) was used to examine forms of nitrogen in typical bituminous coal and its char, and effects of temperature, water vapor on evolution and conversion characteristics of coal nitrogen were investigated. The results indicate that raising temperature and concentration of water vapor are conducive to evolution of char nitrogen. When concentration of water vapor reaches 30%, the char nitrogen evolution reaches a peak. The presence of water vapor facilitates the evolution of N-5 and N-6 from coal char and suppresses that of N-Q and N-X, because the gasification effect of water vapor is beneficial to breaking aromatic structure, but the conversion of N-6 to N-Q and N-X is promoted as a result of H and OH groups brought by the high concentration of water vapor.
Abstract: A degradative solvent extraction at around 350℃ for low-rank coal or biomass wastes upgrading and fractionation was proposed in our previous work. The extraction yield of low-rank coal is relatively lower than that of biomass. In this work the blends of low-rank coal and biomass were treated by this method at 350℃ to investigate the interaction between them. The results showed that the yields and elemental compositions of the extracts obtained from the blends were slight different to the calculated results, which were calculated by assuming that there was no interaction between the coal and biomass. The slight promotion of yield was judged to be caused by the catalytic action of the minerals in the coal for thermal decomposition of biomass. It was worth to note that the elemental composition, molecular weight distribution, chemical structure, thermal decomposition behavior and thermoplastic behavior of the extracts obtained from low-rank coal, biomass and their blend, were rather similar to each other, independent of the properties of the raw feedstocks. Overall, the interaction between low-rank coal and biomass during the extraction was not significant. On the other hand, the proposed degradative solvent extraction method was fit not only by single low-rank coal and biomass but also by their blends to produce the product having similar physicochemical properties. This implied that an industrial system of degradative solvent extraction can use coal, biomass or their blends as feedstock at the same time without modification or adjustment.
Abstract: Four thermal dissolution soluble fractions (TDSFs) with different thermal dissolution soluble yields (TDSYs) obtained from thermal and co-thermal dissolutions (CTDs) of a Chinese sub-bituminous Shenfu (SF) coal and lignin were characterized by elemental analysis, FT-IR and synchronous fluorescence spectrum measurements. The hydro-liquefaction properties of the four TDSFs and SF raw coal with and without catalyst were compared and the recycled use property of the catalyst in hydro-liquefaction of the TDSF from CTD of SF coal and lignin was further probed. The results suggests that the TDSF from the thermal dissolution (TD) of SF coal contained much more amount of aromatic components and polyaromatic hydrocarbons (PAHs) with 4 and more rings than those from the CTD of SF coal and lignin at the same temperature. TDSFs gave much higher liquefaction conversions and oil yields than SF raw coal in hydro-liquefaction with or without catalyst. Almost all TDSF was converted with much high yield of oil and the TDSF from CTD of SF coal and lignin gave higher yield of oil than that from the TD of SF coal in hydro-liquefaction with Ni-Mo-S/Al2O3 catalyst which demonstrated a good reusability in the hydro-liquefaction of TDSF from the CTD of SF coal and lignin. Carbon deposition was hardly observed in the 4 times recycle used catalyst.
Abstract: The pure chemicals were used to simulate the composition of typical ash deposits on heat exchanger surfaces during high-alkali coal combustion, and the thermal mechanical analysis (TMA), TG-DSC analysis and high-temperature calcination were performed to investigate the high temperature melting characteristics of the deposits with varying content of Na2SO4. Subsequently, XRD and SEM-EDS techniques were applied to investigate the reaction products and detailed mechanism. The results indicate that the melting characteristic temperature of deposits decreases significantly after blending with Na2SO4, and the transformation of Na2SO4 is closely related to the blending ratio. When the blending ratio is below 20% (mass ratio), most Na2SO4 is converted to CaSO4 and sodium aluminosilicate, while Na2SO4 would react with CaSO4 and generate sulfate double salts when the blending ratio is over 40%. Moreover, the particles of Na2SO4 enriched deposits begin to adhere at 800℃. When the temperature is elevated to 900-950℃, the low-temperature eutectics are easily formed in the presence of nepheline and albite, and the eutectics and Na-Ca sulfate double salts are gradually molten. The large amount of co-melting of akermanite and Ca-bearing minerals was observed at temperatures of 1200-1250℃, and the minerals are completely melted at temperatures over 1300℃.
Abstract: Decomposition behavior of Chlorella sp. during low-temperature hydrothermal pretreatment (HTP) were studied. Distribution of various product yields, element components, energy recovery ratio and key elements (i.e., C and N) along with temperature (125-200℃) were investigated. The results show that amounts of C and N are enriched into aqueous phase, and high content of NH3-N is detected due to deamination reaction above 175℃. During the HTP process, N distribution in oil product first increases gradually and then rapidly increases above 175℃. During the whole low-temperature HTP process, the yield and energy recovery ratio of solid residue decreases continuously. The N/C and O/C ratio of the solid residue also decreases, indicating HPT would promote property of the solid residue. The functional structure and thermal-degradation of Chlorella sp. and its solid residue are then comparatively examined by various techniques including FT-IR, XPS, TG-FTIR-MS and Py-GC/MS. The results show that functional structure of the solid residue is distinguished from that of the raw sample. The relative content of C-C bond increases while that of C-N and C-O bonds decreases. In addition to protein-N and quaternary-N, a low fraction of pyridine-N is also detected in the solid residue. Compared with these from raw material, less NH3 and HCN are released from solid residue, and less N-containing heterocyclic compounds are generated during rapid pyrolysis.
Abstract: The phenolic substances in the bio-oil fractions collected at different temperature intervals were extracted by barium ion precipitation method at different concentrations of NaOH reagent, reaction temperatures and reaction times, and the extraction effect was analyzed by GC-MS. The results show that the effect of barium ion precipitation on guaiacols separation is more outstanding. The temperature (30-50℃), concentration of NaOH (1.0-6.0 mol/L) and reaction time (10-40 min) have great influence on the extraction rate of guaiacols. The optimum reaction parameters include the NaOH solution of 5.5 mol/L, the temperature of 35℃ and the reaction time of 20 min. Under the optimum condition, the extraction rate of guaiacols in the three fractions of low temperature water, low temperature oil and high temperature are 34.1%, 33.8% and 33.5%, respectively.
Abstract: A novel carbon-based solid acid catalyst was prepared with chelates of sodium carboxymethyl cellulose and iron sulfate as a carbon precursor, and with concentrated sulfuric acid as sulfonation agent. The physical and chemical properties of prepared catalyst were characterized by Fourier transform infrared (FT-IR), X-ray diffraction (XRD), pyridine-FTIR, scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and energy dispersive spectroscopy (EDS). It was used to catalyze the esterification of oleic acid with methanol to prepare biodiesel, and the influence of different reaction conditions on the conversion of oleic acid was investigated. The results show that the catalyst is a solid acid one with both Lewis and Brønsted acid sites. The conversion of oleic acid reaches 96.8% at the reaction temperature of 70℃, the reaction time of 6 h, the molar ratio of oleic acid to methanol of 1:10, and the catalyst dosages of 7.5% based on oleic acid. In addition, the stability performance of the catalyst tested indicates that the catalyst has a good reusability and hydrophobicity.
Abstract: Two ionic liquid antioxidants ([MI] [C6H5COO], [Ch] [C6H5COO]) were designed, and synthesized, and measured by nuclear magnetic resonance spectra and Fourier infrared spectra.The effects of two ionic liquid antioxidants on the oxidation resistance, copper corrosion and oil solubility of Jatropha biodiesel were studied.The results show that ionic liquid antioxidants can effectively improve the oxidative stability of biodiesel. When the addition amount of[MI] [C6H5COO] is 0.3‰, the induction period of Jatropha biodiesel increases by 238%, exceeding the national standard (6 h). However, when the addition amount of[Ch] [C6H5COO] is 0.3‰, the induction period of Jatropha biodiesel increases by 141%, which does not meet the national standard. The order of oil solubility from large to small is[MI] [C6H5COO] > [Ch] [C6H5COO] > GA (raw material for synthesizing ionic liquid antioxidants).Moreover, the experiments show that the synthetic properties of[MI] [C6H5COO] containing lipophilic cations in the two ionic liquid antioxidants are significantly better than those containing hydrophilic cations[Ch] [C6H5COO].
Abstract: A series of H-ZSM-5 zeolites with a silicon to aluminum ratio of 50-4000 but similar crystal size were synthesized and characterized by XRD, N2 sorption, NH3-TPD and Py-FTIR; the intrinsic effect of silicon to aluminum ratio on the selectivity to propene in the conversion of methanol to propene (MTP) was investigated. The results show that a complete conversion of methanol can be initially achieved over H-ZSM-5 with a silicon to aluminum ratio from 50 to 1600 and then the initial conversion of methanol decreases progressively with further increasing the silicon to aluminum ratio. Meanwhile, the selectivity to propene increases monotonically with an increase in the silicon to aluminum ratio of H-ZSM-5 for MTP with a complete methanol conversion, suggesting that a high Si/Al ratio for H-ZSM-5 may enhance the propagation of the alkene-based methylation/cracking cycle relative to the arene-based methylation/dealkylation cycle in MTP. A critical value of acid density, viz., [AS]S, is required to achieve the maximum propene selectivity for MTP with a complete methanol conversion; this critical[AS]S value is 0.175 μmol/m2 for the H-ZSM-5 zeolite under current reaction conditions.
Abstract: A series of Cu-Ni bimetallic catalysts derived from nickel-malachite were prepared by an oriented isomorphous substitution method. The effects of the precursor structure and catalysts surface composition on the catalytic performance CO hydrogenation to ethanol were investigated in an agitated slurry autoclave reactor. The studies demonstrated that the pure (Cu, Ni)2CO3(OH)2 phase was obtained by oriented isomorphous substitution method and Ni2+ was rich on the (Cu, Ni)2CO3(OH)2 precursor surface. Uniform distribution of (Cux, Ni1-x)O solid solution were found in CuO crystal lattice. After calcination, the (Cux, Ni1-x)O solid solution dispersed in the crystal structure of CuO uniformly. Cu and Ni dispersed in the catalysts evenly to form an active interface after reduction, which promoted the synthesis of higher alcohols. Discontinuously distributed Ni-active sites prevented the carbon chain from growing further, and enhanced the selectivity of ethanol. The catalyst prepared by the feeding materials with Ni/Cu molar ratio=45:100 was found to exhibit higher activity and ethanol selectivity due to the strong interaction between (Cux, Ni1-x)O solid solution and CuO phase.
Abstract: BaZr0.9Y0.1O3 with perovskite structure was prepared by solid-phase reaction method and used as support to prepare Fe2O3 based catalysts. X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM) were used to observe the crystal phase structure and microscopic morphology of the prepared catalysts. The catalyst performance for the reverse water gas shift reaction was also investigated. The results showed that the supported catalyst has better catalytic activity when the BaZr0.9Y0.1O3 powder was calcined at 1200℃ for 5 h. BaZr0.9Y0.1O3 has an obvious catalytic effect on the reverse water gas reaction, and the Fe2O3-supported catalyst can significantly promote CO2 reduction. Moreover, loading small amount of Fe2O3 has apparent effect on the reactivity of the catalyst. When the space velocity was 1.13 h-1, the CO yield can reach 31% at 650℃. Carbon deposition on the catalyst during the CO2 reduction process was taking place in a low rate, leading to a significant increase in the CO yield in the process of cooling-down experiment. In addition, the activity of the catalyst did not significantly decrease after a long period of reaction, which proved that the activity of the prepared catalyst was relatively stable.
Abstract: It was found in recent years that inorganic semiconductor materials exhibited excellent photocatalytic performance and had broad application prospects in environmental treatment and energy conversion; in this aspect, Cu2O semiconductor has attracted extensive attention owing its superior adsorption capacity for oxygen and high photo absorption coefficient. Considering that doping in Cu2O could improve its photocatalytic efficiency in the visible region, in this work, the formation energy, electronic structure, and photocatalytic properties of Cu2O doped with different concentrations of Cr were investigated by first-principle calculation. The results indicate that intrinsic Cu2O shows semiconductor properties and the absorption of visible-light is weak; after doping with different concentrations of Cr and in different positions, the Cr-doped Cu2O system are all stable and show metallic characteristics. Compared with intrinsic Cu2O, the absorption peaks of Cr-doped Cu2O in the visible-light range are enhanced. When two Cr atoms are doped in the nearest neighbor configuration, the absorption coefficient in the visible-light region is the largest, with the strongest photocatalytic efficiency. The density of states shows that the visible-light absorption of Cr-doped Cu2O systems is mainly induced by the intra-band transition of electrons in Cr 3d states. The doping concentration and configuration influence mainly the physical properties of Cu2O in the long wavelength range, but have little effect in the short wavelength range. Therefore, an increase in the doping concentration of Cr dopants and a change in the configuration can improve its photocatalytic efficiency in the visible region, and then promote the progress of Cu2O application in photocatalysis.
Abstract: The deep eutectic solvent (DESs) of EMIES/p-TsOH was synthesized by stirring a mixture of 1-ethyl-3-methylimidazolium ethyl sulfate (EMIES) and p-toluene sulfonic acid (p-TsOH), the structure of catalysts was characterized by infrared analysis (FT-IR), hydrogen spectrum analysis (1H-NMR) and thermogravimetric analysis(TG), the desulfurization performance of model oil was investigated using EMIES/p-TsOH as a catalyst and extraction agent and using H2O2 as the oxidation, and the effects of the temperature, n(H2O2)/n(S) molar ratio, and the amount of DESs on the desulfurization activity were investigated in detail. Under the optimal conditions, the removal rate of dibenzothiophene (DBT), 4, 6-dimethyldibenzothiophene (4, 6-DMDBT) and benzothiophene (BT) can reach up to 96.2%, 92.2% and 88.8%, respectively. After five recycling runs, the removal rate of DBT can still reach 93.6%. The kinetic analysis of the desulfurization system indicates that the apparent activation energy is 66.4 kJ/mol.
Abstract: The Mn/MIL-100 (Fe) mercury removal agent loaded with 6% Mn was prepared by impregnation method using Fe-based metal organic framework (MOFs) as the support. A set of fixed bed reactor apparatus was installed and used to study the performance of Mn/MIF-100(Fe) to remove elemental mercury (Hg0) in the simulated flue gas. The materials were characterized by XRD, XPS, BET and TGA. The results showed that Mn/MIF-100 (Fe) had high efficiency in removing elemental mercury (Hg0). When the GHSV was 180000 h-1 at 250℃, the mercury removal (Hg0) efficiency was above 82%. The main mercury removal mechanism of Mn/MIF-100 (Fe) was oxidation, and the loading of Mn promoted the adsorption of mercury. With the increase of flue gas temperature, the oxidation efficiency of elemental mercury was gradually increased. O2 and NO promoted the removal of mercury while SO2 and NH3 inhibited the removal of mercury. Mn/MIL-100(Fe) had a strong adaptability to the complex flue gas as a whole.
Abstract: Using a horizontal tubular reactor together with chemical adsorption, release characteristics of corrosive gases, viz., HCl and H2S, during steam and CO2 gasification process of aged and normal refuse derived-fuels char (ARC and NRC) were investigated. Effects of gasification temperature, type and flow rate of gasification medium on their release behaviors were examined. In H2O gasification at 950℃ the carbon gasification rates, HCl and H2S yields of ARC are 66.1%, 100% and 74.9%, respectively, and those are 77.8%, 100% and 2.9% in CO2 gasification, respectively. The carbon gasification rates, HCl and H2S yields of NRC in H2O gasification are 98.8%, 100% and 53.7%, and those are 100%, 96.2% and 10.3% in CO2 gasification, respectively. The release characteristics of HCl and H2S are investigated with different flow rates of H2O and CO2 in the NRC gasification. HCl and H2S yields of NRC increase with increasing flow rate of H2O, but the promoting effect can be ignored when H2O/C is ≥ 3.3. HCl yield of NRC increases but H2S yield decreases with increasing flow rate of CO2.
Supervisor：Chinese Academy of Sciences
Sponsors by：Shanxi Institute of Coal Chemistry, Chinese Academy of Sciences Chinese Chemical Society
