Abstract: Yunnan brown coals with different moisture contents were prepared by vacuum-drying and thermostatic and humidistatic treatment, and the effects of moisture on the rheological behavior of brown coal-oil slurries were studied at atmospheric pressure and room temperature(t=19.3 ℃, p=1.01×105 Pa). It is found that the moisture contents in raw coals have influences on the rheological properties of brown coal-oil slurries. The viscosity of the slurry decreases first and then increases with the increase in moisture. The moisture content ωmin at which the lowest viscosity occurs varies with shear rates and coal loadings. ωmin is 9.20% at the shear stress less than 4.4 s-1 and 7.80% at the shear stress greater than 4.4 s-1 as the coal concentration is 45.45%. ωmin becomes 7.40% at the shear stress less than 1.32 s-1 and 10.00% at the shear stress greater than 1.32 s-1 as the coal concentration is 55.56%. The thixotropy of brown coal-oil slurries is different for different moisture contents, and is enhanced with the decrease in the moisture contents. Brown coal-oil slurries containing moisture of various contents are pseudoplastic fluid, and the moisture contents also have some effects on the parameters of the rheological model.
Abstract: This paper illustrates the occurrence and distribution of sulfur in coal from the perspective of composition and structure of the coal body. With the organic sulfur-rich Xinyu clean coking coal as the sample, and the method of separating all group components from coal through extraction and stripping process as well as X-ray photoelectron spectroscopy (XPS) and gas chromatography/mass spectrometer (GC/MS) analysis techniques, the content of inorganic sulfur and organic sulfur of different forms in raw coal and various group components isstudied and the occurrence of organic sulfur in organic matter of coal is carefully observed. The results show the distribution of inorganic sulfur is mainly dependent upon its particle size and density in coal and has less relationship with the structure of group components of coal. Thiophene sulfur is the major form of organic sulfur either in raw coal or group components. The external environment of molecules dominated by conjugated structure can decrease the electron binding energy of organic sulfur in conjugated structure, while increase that of sulfur in aliphatic structure. The distribution of organic sulfur in coal is balanced as a whole and will not be significantly influenced by structural differences of group components. However, the occurrence of organic sulfur compounds is associated with the structure of group components, showing relatively small difference. And there is only one type of small molecule organic sulfur compounds in light component, with small abundance.
Abstract: The occurrences of trace elements in Fushun, Longkou and Maoming oil shale samples were determined using float-sink test and demineralization. The results of float sink test are consistent with that from demineralization. Most trace elements occur in inorganic mineral, but there are still some differences among the 3 oil shales. The trace elements of V, Mn, Zn, Sr, Mo, Ta, Cd are found in the samples. Cr, Te in Fushun, Cd, Sn in Longkou, and Cd, Sn, Pb in Maoming are primarily associated with mineral matters. The trace elements of Cr, Te in Maoming, Cd in Fushun, and Pb in Longkou oil shale samples are primarily associated with organic mineral. Part of Co, Sn, Pb in Fushun, Co in Longkou and Maoming oil shale samples are associated with organic mineral, while most of them are associated with clay mineral.
Abstract: With sodium carbonate and sodium dodecyl benzene sulfonate used as the catalysts respectively, the steam gasification kinetic experiments of Fujian Jianxin and Chuanghong anthracites were conducted in an atmospheric thermal balance, and the effects of catalyst loading amount(0%~15%) and gasification temperature (850~950 ℃) were examined. The experimental data were fitted by shrinking core model. Meanwhile, the kinetic parameters were obtained. The results show that both sodium carbonate and sodium dodecyl benzene sulfonate can significantly increase the gasification rate and reduce the activation energy of gasification reaction of the two anthracite samples. Because the loading process of catalyst LAS can make the sodium ions being dispersed more evenly, even with low concentration of Na+, the carbon conversion can be improved significantly and the gasification reaction time is reduced too. The experiments prove that it is a new way for the application and development of LAS in catalytic steam gasification of Fujian anthracite.
Abstract: Biomass chars were prepared under different pyrolysis pressures in a pressurized fixed bed reactor. The evolution of chemical composition and physical structure of the biomass chars with the change of pyrolysis pressure were observed by BET, XRD, CHNS elemental analyzer and ICP-AES. The reactivities of biomass chars were evaluated by a thermogravimetric analyzer. The results show that the yields of biomass chars increase with increasing pyrolysis pressure, but reach a plateau above 1.0 MPa. With increasing pyrolysis pressure C content in biomass chars increases, while H content and BET surface area decrease. The degree of graphitization of corn stalk char and sawdust char increases with increasing pyrolysis pressure, while that of rice husk char shows almost no dependence on pyrolysis pressure. The average gasification rates of corn stalk char and sawdust char all decrease with increasing pyrolysis pressure, while pyrolysis pressure has little influence on the gasification rate of rice husk char. Compared the evolution of BET surface area and carbon crystallite structure of biomass chars with biomass char gasification rate, it shows that the difference of carbon crystallite structure of biomass chars, which was brought out by the change of pyrolysis pressure, mainly contributes to the difference of gasification rate of biomass chars prepared under different pyrolysis pressures.
Abstract: Calculations of reactions between biomass char and oxygen carriers CuO were conducted via the method of Gibbs free energy minimization. The effect of temperature, mass ration of oxygen carrier/biomass char and pressure on the gasification of biomass char was examined. The reactions were experimentally investigated using thermogravimetric analysis and scanning electron microscopy (SEM). The results show that when using CuO as oxygen carrier in chemical looping gasification (CLG) of biomass char, the conversion rate of biomass char is improved with increasing reaction temperature. The oxygen carrier CuO starts to sinter when the reaction temperature is above 750 ℃. The addition of oxygen carrier has the best enhancement on the CLG of biomass char with mass ratio of biomass char/CuO being 1:6. It is also found that the increase of reaction pressure would inhibit the CLG of biomass chars.
Abstract: Activated coke modified with manganese acetate (Mn-AC) was prepared through incipient impregnation and characterized by nitrogen sorption, X-ray photoelecuon spectroscopy (XPS) and X-ray diffraction (XRD). Mn-AC was used as a sorbent in the removal of elemental mercury in a simulated syngas (0.04% H2S, 20% CO, 30% H2 and balanced N2) and the various actors influencing the removal efficiency were investigated in a bench-scale fixed-bed reactor. The results indicated that Mn-AC exhibits excellent Hg0 removal capacity at 200 ℃ and 84.3% of Hg0 can be removed from the syngas. H2S present in the syngas can obviously promote the Hg0 removal efficiency at high temperature, as H2S is oxidized to elemental sulfur (Sad) that provides active adsorption sites for Hg0 to form HgS. Both H2 and CO are unfavorable to mercury removal, as H2 may deplete the active oxygen in the sorbent surface and CO may react with the active sulfur sites (forming COS). At high temperature, mercury removal is suppressed, which may be attributed to that the interaction between Hg0 and active sulfur sites is weakened and reducing capacity of H2 is strengthened, resulting in the decrease of the active sites for mercury adsorption.
Abstract: The research on the issue of material corrosion in catalytic coal gasifier was focused on, in which the potassium carbonate and the coal ash from catalytic coal gasification with high alkali content were used to test the corrosion to the corundum refractory. The corundum refractory corroded by alkali metals at different reaction atmospheres, temperatures, reaction time, and alkali metal forms was characterized by using scanning electron microscope and energy spectrum analysis(SEM-EDX), X-ray diffraction (XRD) analysis, and 27Al nuclear magnetic resonance (NMR) analysis. The results show that the corrosive behavior of alkali metals on refractory is affected by temperature, reaction atmosphere, reaction time, and alkali metal forms. Specially, the more serious corrosion of corundum refractory in air takes place due to a new phase, potassium aluminate, being formed via chemical reaction between potassium carbonate or coal ash with high alkali content and corundum refractory, and the content of potassium aluminate increases with increasing temperature and reaction time.
Abstract: Methanol conversion to DME was investigated over CuO/H-MOR nanocatalyst prepared by precipitation and/or by precipitation flowed by ultrasonic irradiation methods. BET, XRD, SEM, NH3-TPD and H2-TPR techniques were used to characterize nanocatalysts. The effective ultrasonication factors encountered during carrying out the dehydration of methanol on Cuo/H-MOR zeolite catalysts to produce dimethylether are studied in the present work. These factors include: the type of ultrasonication media, the ultrasonication time, and the fixed weight of the solid catalyst per the volume of the ultrasonication liquid media (Wcatalyst/Vliquid ratio). XRD showed that structure of H-MOR is not damaged even after it is loaded with CuO nanoparticles or with ultrasonication. H2-TPR profiles indicated that reducibility of sonicated CuO/H-MOR nanocatalyst is higher than non-sonicated catalyst. It is found that employing ultrasound energy for 60 min has the highest influence on the surface properties of nanocatalyst and its catalytic performance (activity and stability) of CuO/H-MOR catalyst. Surface morphology (SEM) of the sonicated CuO/H-MOR catalysts have clarified that methanol by itself used as an ultrasonication medium gives the best results concerning the homogeneity of particle sizes compared to the non-sonicated catalyst, where large agglomerates and non-homogeneous clusters appeared. Water used as a sonication medium showed many large agglomerates in addition to some smaller particles resulted in low catalytic activity. The different alcohols and (Wcatalyst/Vliquid) ratio were examined to give precise correlation with the catalytic activity of the sonicated CuO/H-MOR zeolite catalyst. These findings certified that ultrasonication has a deep effect on the surface morphology and hence on the catalytic behavior of the dehydration of methanol to DME. NH3-TPD shows that ultrasound irradiation has enhanced the acidity of CuO/H-MOR catalyst and hence it's catalytic performance for DME formation.
Abstract: The catalytic properties of ZnO-modified copper ferrite in water-gas shift (WGS) reaction were evaluated between 250 and 400 ℃. The Zn2.5-Cu/Fe (modified by 2.5% ZnO) showed high catalytic activity. The catalyst was characterized with XRD, SEM, H2-TPR and CO2-TPD techniques and N2 sorption experiment. It was shown that introduction of appropriate amounts of ZnO transformed the CuFe2O4 from the tetrahedral crystalline phase to the cubic, enhanced the CuFe2O4 reducibility, and increased the amount of weak and medium basic sites. As a consequence, the interaction between copper and iron species was improved and the catalytic activity was increased.
Abstract: A series of manganese oxide octahedral molecular sieves (OMS-2) were prepared by different methods for the purpose of investigating the effect of the preparation methods on their catalytic properties in selective catalytic reduction (SCR) of NOx with NH3. These samples were characterized with BET, XRD, Raman, H2-TPR, XPS and TEM techniques. It was found that all the samples showed higher NOx conversions than MnOx in the temperature range from 50 to 150 ℃ due to their easier reduction behavior, and the NOx conversion reached about 100% at 120 ℃. Nonetheless, the preparation methods have a great effect on the catalytic activity of OMS-2. The sample prepared by the solid-state method shows the highest catalytic activity. The BET, XRD, TEM and XPS results reveal that this because it has lower crystallinity but higher dispersion as result of the presence of larger amounts of surface lattice oxygen and less crystalline MnO2 species.
Abstract: The effect of FeOx and SnOx additives on the catalytic performance of MnOx-CeO2 supported on activated carbon honeycomb (MnOx-CeO2/ACH) in NO removal at low temperature was investigated. The results indicated that the addition of FeOx can improve the distribution of manganese and cerium oxides on the ACH support and enhance the resistance to SO2 poisoning in NO removal; the activity of FeOx-modified MnOx-CeO2/ACH increases with the increasing reaction temperature from 80 ℃ to 200 ℃. Meanwhile, the MnOx-CeO2/ACH catalyst modified with SnOx exhibits high NO removal activity and good resistance to SO2 poisoning at relatively high temperatures; over SnOx-modified MnOx-CeO2/ACH at 250 ℃, NO conversion decreases slightly from 98.6% in the absence of SO2 to 87.8% in 700 min upon the introduction of SO2 in the feed.
Abstract: CuO/SC catalysts were prepared by incipient wetness impregnation and characterized by BET, XRD and SEM. Their performance for NO oxidation was tested in a fixed bed reactor. The influence of CuO content, reaction temperature, space velocity, concentration of O2 and H2O on NO catalytic oxidation activity were investigated. The results show that CuO/SC with 1% CuO loading had the highest activity at 70 ℃, 5% of O2 and 1 000 h-1 of GHSV. In addition, the poisonous effect of water vapor on catalytic oxidation activity was also analyzed. When water vapor was introduced into the feed gas, breakthrough time is reduced from 15 h to 9.5 h.
Abstract: The effect of water vapor on NO reduction by methane over iron was investigated at 300~1 100 ℃ in an electrically heated ceramic tubular flow reactor in both N2 and simulated flue gas atmospheres. The iron samples before and after reaction were characterized by XRD, SEM and XPS. The results demonstrated that water vapor has a small effect on NO reduction by methane over iron. In N2 atmosphere, water vapor is involved in the oxidation of iron; compared with that in the absence of water vapor, the NO reduction efficiency is decreased slightly when 2.5%~7% water vapor is added into the reaction stream. However, the NO reduction efficiency increases with the increase of water content from 2.5% to 7%, as water vapor may promote the oxidation of iron, forming porous iron surface. Methane is involved in the reduction of the iron oxides, leading to the formation of a dense layer of Fe3O4 and FeO, which may inhabit the interaction of NO with metallic iron and then decrease the NO reduction efficiency, as compared with that without methane. In the simulated flue gas atmosphere, water vapor promotes the NO reduction by methane over iron. When the excess air ratio is 0.7 in reaction zone (SR1) and 1.2 in burnout zone (SR2), the NO reduction efficiency at 1 050 ℃ is 96.7% in the presence of 7% water vapor, compared with the value of 90.6% in the absence of water vapor. SO2 causes a slight decrease of NO reduction. Long term test results showed that over iron at 1 050 ℃ in the simulated flue gas atmosphere containing 7% H2O and 0.02% SO2, NO reduction efficiency remains higher than 90% after reaction for 50 h in the presence of 1.14% methane.
Abstract: The present paper investigated the effect of Zn modified HZSM-5 catalysts on the reaction performance of methanol to aromatics with the presence of alumina. The catalysts were characterized by BET, XRD, Py-FTIR, NH3-TPD, and H2-TPR techniques, respectively. The experimental result demonstrated that the introduction of alumina produced mesopores in the HZSM-5 catalyst and strengthened the stability of Zn species on the surface of the catalyst. The introduction of Zn species broke the structure of HZSM-5 zeolite and changed the surface acidity of the catalyst. In addition, Zn species might contribute to the dehydrogenation reaction of MTA. Meanwhile, the subsequent aromatization process of olefins was impressed. Within the scope of this study, the maximum value of aromatic yield (C6~11) reached 21.0% when the loading of Zn was 0.5%. The aromatization of methanol is at the control of coke on the catalyst. However, the regenerated catalyst exhibited a higher aromatic yield.
Abstract: A new amino-acid functionalized heteropoly tungstate ([Ala]3PW) was prepared with alanine and phosphotungstic acid as raw materials. The structure of [Ala]3PW was characterized by XRD, FT-IR. The removal of dibenzothiophene (DBT) in model oil was studied by using [Ala]3PW as catalysts, hydrogen peroxide as oxidant and imidazolium tetrafluoroborate ([HMIM]BF4) as the extractant. The influence of reaction temperature, the amount of catalysts, the molar ratio of O/S(H2O2/DBT), the amount of extractant and types of thiophene on the desulfurization efficiency were investigated. The results indicated that under the optimal reaction conditions of 10 mL model oil, 0.04 g of [Ala]3PW, O/S(mol ratio) =6, V([HMIM]BF4)/V(oil)=0.6, reaction temperature of 50 ℃ and reaction time of 180 min, removal of DBT was found to be 98.2%. The catalyst could be recycled 4 times without a significant decrease in activity.
Abstract: Nickel phosphide catalysts, supported on whiskers and anatase TiO2, were prepared by temperature programmed reduction method and solvothermal method, respectively. The catalysts were characterized by X-ray diffraction (XRD), N2-adsorption specific surface area measurements (BET), N2 adsorption-desorption,CO adsorption, X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (TEM). The effects of preparation method and support type on catalyst activity for dibenzothiophene (DBT) hydrodesulfurization (HDS) were studied. The result showed that the structures of the TiO2 support remained unchanged, and the formation of TiPO4 was suppressed in solvothermal method process, contributing to higher catalytic activity of Ni2P/TiO2 catalysts for HDS than the catalysts obtained by conventional TPR method. Compared with the catalysts supported on anatase TiO2, the catalysts supported on whiskers TiO2 displayed excellent surface properties, producing more Ni2P crystal particles with smaller size and better dispersion, and therefore possessed higher HDS activity. The HDS activity of the catalyst supported on whiskers TiO2 and made by solvothermal method was found to be the best one among the tested catalysts. The conversion of dibenzothiophene HDS was 98.2% under the selected reaction conditions of 340 ℃, 3.0 MPa, H2/oil ratio of 500 (volume ratio), and WHSV of 2.0 h-1.
Supervisor：Chinese Academy of Sciences
Sponsors by：Shanxi Institute of Coal Chemistry, Chinese Academy of Sciences Chinese Chemical Society
