Abstract: Xinyu clean coal rich in organic sulfur was chosen to study the distribution of organic sulfur with different structures in raw coal and its group components. Analysis techniques including X-ray photoelectron spectroscopy (XPS), gas chromatography/mass spectrometer (GC/MS), etc. and separation methods of extraction and stripping and fractional extraction were applied, with a focus on the occurrence of different organic sulfur in coal organic matter and its group components. The results show that there is a significant negative correlation between the occurrence ratio based on total sulfur in some group components and the structure complexity. The distribution of soluble sulfur-containing components in total dissolving-out substances is generally uniform, compared with that in each group component. Most soluble organic sulfur with conjugated structure is distributed over the dense medium component, but fewer in loose medium component, which is predominantly in the form of thiophene sulfur, and the fewest in heavy component. Soluble organic sulfur with aliphatic structure is mainly distributed over heavy component and dense medium component, but rarely in loose medium component. Evident additivity is observed in the extract yield of organic sulfur in each group component with the change of extraction time while the dissolution behaviors of soluble sulfur-containing components in the group component are mutual independence. This is consistent with the basic idea of coal inbuilt structure model. The occurrence of organic sulfur in coal follows the rule of similarity-intermiscibility.
Abstract: The Tianchi Mulei high-alkali coal gasification in a circulating fluidized bed (CFB) was conducted to study the operating characteristic and the migration of alkali metals, and the phenomenon of bed particles agglomeration was examined by some analytical technologies. The results show that the water-soluble and ammonium-acetate-soluble Na is released into gas while the insoluble Na is mainly remained in semi-char, indicating that the transformation of alkali is different for different modes of occurrence. At higher gasification temperature, both of Na existed in slag and gas become more, while the Na in fly ash declines. The condensation rate of Na in gas phase is higher than that of K with the decreasing of down stream temperature. It seems that the degree of agglomeration increases with the increase of temperature, resulting in bed temperature fluctuation. The eutectic with strong viscosity, formed by a direct reaction between alkali and mineral component of ash or SiO2 of bed material, is considered as the key factor leading to the agglomeration of particles.
Abstract: Thermogravimetric characteristics and evolution of main gaseous products during hydrogenation of two coals were studied in a thermogravimetry-gas chromatography combined system at 15℃/min, 0.1~5MPa and a final temperature of 1000℃. The results show that the hydrogenation process occurs in four stages: drying and degassing, hydropyrolysis, rapid hydrogasification, and slow hydrogasification. With increasing hydrogen pressure, hydrogenation of volatile radicals is promoted and decomposition of oxygen-containing functional groups forming carbon oxides is inhibited. During hydropyrolysis stage, the weight loss rate increases with hydrogen pressure for FG coal, while the hydrogen pressure has little influence on that for HLE coal. During the rapid hydrogasification stage, the evolution rate of CH4 increases with hydrogen pressure; for HLE coal the evolution rate of CH4 doesn't increase with hydrogen pressure any more at high pressures (3~5MPa). The HLE coal with higher oxygen content contains more active sites provided by the oxygen-containing groups in the semi-char. The FG coal with higher H/C atomic ratio is able to provide more hydrogen by itself during hydrogenation reactions. The kinetic data of the slow hydrogasification stage is k0=2.38×107 (min-1·MPa-1), E=231kJ/mol, n=1 for the FG coal and k0=2.64×103 (min-1·MPa-0.736), E=127kJ/mol, n=0.736 for the HLE coal.
Abstract: The hydrogenation of coal tar atmospheric residue (CTAR) was conducted in a slurry-bed hydrocracking pilot plant with a 3000mL loop reactor; the toluene insoluble (TI) fraction and coke were separated from CTAR and hydrogenation product, respectively. The properties of TI and coke were analyzed by means of element analysis, SEM, XRD, FT-IR and XPS; the relevance of TI structure to the coking behavior in the hydrogenation process was then investigated. The results show that the slurry-bed hydrocracking of CTAR has the features of high light oil yield, little coke, and almost no coke on the reactor surface. TI consists of carbonaceous, mineral particles and polycyclic aromatic hydrocarbons originated from the coal tar production process. O is the dominant heteroatom, whereas Ca, Si, Al, and Na are derived from minerals in CTAR. Furthermore, C and O are mainly present as C-C, C-H, C-O-C and C-OH, whereas N-containing groups appear as pyrrole and amine and S is mainly in the form of aliphatic sulfur. Obviously, TI has a layered stack structure, which can be easily broken to smaller carbonaceous and mineral particles (several microns) with larger specific surface area and adsorption capacity. These particles, together with the sulfurized catalyst, act as the coke centers, which are effective to adsorb macromolecular radicals and then reduce the opportunity of coking on the reactor surface.
Abstract: A Ni-dolomite catalyst with promoter Lanthanum was prepared by kneading method. The catalyst was used for the cracking reaction of tar model compound containing N-dodecane, cyclohexane, toluene and methylnaphthalene in an atmospheric fixed reactor. The effects of temperature, space velocity and the ratio of water and ingredient on the yield of gas products were examined. The stability test and reaction-regeneration experiments were conducted. Moreover, cracking characteristics of dust-containing tar over the catalyst and dust deposition mechanism were investigated. The results show that the optimum operating condition for the catalyst is reaction temperature 800℃, space velocity 300h-1, the ratio of water to ingredient 5:1. The optimum regeneration condition is 700℃ and 1h. XRD results show that MgO-NiO solid solution and La(NiO3) crystalline phase are converted in the modified dolomite catalyst. Different dust species depositing on the catalyst surface have different influences on the catalytic activity. CaO can improve the catalytic activity. The deposition of Fe2O3 can convert into a new crystalline phase NiFe2O4. SiO2 plays a promoting role in carbon deposition, which can significantly inhibit the catalytic activity.
Abstract: The slurryability, rheological characteristics and stability of petroleum coke water slurry (PCWS) with different particle size distribution were studied. The results show that the slurryability of petroleum coke was good, and the solid concentration was about 70%. The apparent viscosity of PCWS increases with the petroleum coke concentration increase. The PCWS with wider particle size distribution has the better close-packing and higher stacked efficiency, which results in the higher solid concentration with fewer dispersants. The PCWS behaves as a dilatant fluid with naphthalene series dispersant. The dilatability decreases with the wide distribution of particle size. The stability of PCWS is evaluated by using standing observation and Turbiscan Lab stability analyzer methods. When the particle size is larger, the stability of PCWS is worse, the drainage rate is lower, and the petroleum coke particle coalescence and hard sedimentation are easy formation. Particle coalescence is the main factor influencing the stability of PCWS.
Abstract: The palm kernel shell(PKS) chars of different conversions were prepared in a tube furnace by using CO2 as gasification agent, and the gasification reactivity of PKS chars were tested by thermogravimetry analyzer. The pore structure, degree of carbon structure ordering, mineral element content and distribution of PKS chars of different conversions were characterized by surface area measurement, Raman spectra, X-ray flourimeter(XRF), scanning electron microscopy and energy dispersive X-ray spectroscopy(SEM-EDX), respectively. The results show that the fixed carbon content of PKS chars reduces gradually, and the proportion of ordered carbon stabilizes at 0.30~0.33 during CO2 gasification. The ash content increases gradually along with the increasing of conversion, but the gasification reaction index Rs of PKS chars increases after a decreased stage. At the early stage of pore size expansion (conversion x< 23%), the change tendency of Rs of PKS chars is in accordance with the surface area. As the gasification reaction continues (23%< x< 31%), Rs has few changes. The surface area of PKS chars has a linear correlation with the conversion from 31% to 68%, and Rs increases with the increasing surface area and the catalysis of mineral elements as x> 56%. When x> 68%, the Rs of PKS chars is mainly controlled by catalysis of minerals.
Abstract: Particle agglomeration, fouling on the heating surface and other issues are closely related to the alkali metals during biomass thermo-chemical conversion. The potassium fixation ability and ash fusing characteristics in the combustion of rice straw (RS) added with ammonium dihydrogen phosphate (NH4H2PO4) were studied in a 21%O2/79%CO2 atmosphere. The reaction residue from the experiment in a drop tube furnace was analyzed with inductively coupled plasma atomic emission spectrometer (ICP-AES), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The potassium retention ratio of co-combustion of RS and NH4H2PO4 is higher than that of RS alone, especially at 900℃, and the retention ratio increases from 14.65% to 68.79%. The reaction between NH4H2PO4 and alkali metals in rice straw leads to the formation of KPO3 at 700 ℃ and K2CaP2O7 at 900℃, which is a high melting point compound. SEM analysis on residue indicates the agglomeration is inhibited, and the ash fusion temperature of RS is increased by adding NH4H2PO4. These results can be helpful to the research and development of high-alkali biomass clean utilization process.
Abstract: H-ZSM-5 was modified with gallium by the ion-exchange method and characterized with XRD, SEM, BET, NH3-TPD, Py-IR, ICP, and XPS techniques. The influences of the Si/Al mol ratios and the pretreatment conditions of the Ga-modified ZSM-5 ((Ga-H)-ZSM-5) on their acidity, gallium species state, and aromatization performance of propane were investigated. It was found that the Si/Al mol ratio had significant effects on the catalyst acidity and the interaction of non-framework Ga species with zeolite, and hence, the catalytic activity and selectivity for propane aromatization. At 550℃ and WHSV of 1.0h-1, (Ga,H)-ZSM-5 with a Si/Al mol ratio of 30 showed the highest catalytic activity. It was shown that Ga species improved the aromatics selectivity and inhibited cracking reactions. After being reduced in hydrogen, Ga2O3 was most likely transformed into Ga+ and GaH+2 species, and migrated into the zeolite channels. Subsequent air-oxidation treatment of the reduced (Ga,H)-ZSM-5 led to formation of GaO+ species, thus greatly increasing the aromatization activity.
Abstract: Nanorod-shaped La(OH)3 support was prepared by hydrothermal method, over which the supported Ni/La(III) catalysts were obtained through wet impregnation method; the influence of calcination temperature on the performance of Ni/La(III) catalyst in the hydrogenolysis of sorbitol to low-carbon glycols was then investigated by means of XRD, SEM/EDS, BET, H2-TPR-MS, CO/CO2-TPD-MS, ICP-AES and TG. The results revealed that the Ni/La(III) catalysts are highly active for sorbitol hydrogenolysis; the yield of low-carbon glycols reaches 53% after reaction at 220℃ and 4 MPa H2 for 1.5 h. The catalyst calcined at low temperature (500℃) is mainly in the form of NiO/La2O2CO3, which may transform into La2NiO4-La2O3 with the increase of calcination temperature. The basicity is a crucial factor for the hydrogenolysis activity; high calcionation temperature may enhance the basicity of the catalysts and then improve their hydrogenolysis activity, whereas the calcination temperature has little effect on the products selectivity. However, NiO/La2O2CO3 exhibits better hydrothermal stability than La2NiO4-La2O3 for sorbitol hydrogenolysis. The deactivation of catalysts can be attributed to the separation of active Ni particles from the support and the agglomeration of the active species, which may reduce the amount of the active metal sites and destroy the catalyst structure.
Abstract: The activity and selectivity to isomerization of pure n-butane and mixed butane (with different proportions of iso-butane) of Au/HZSM-5 catalysts were evaluated using a micro-scale pulse reactor. Results showed that the conversion of pure n-butane was above 7.0% and the selectivity to iso-butane could be as high as 80% on Au/HZSM-5 catalysts with 1.31% Au loading at 300℃. By contrast, the conversion of n-butane and the selectivity to iso-butane was only 0.55% and 11.67% on the HZSM-5 supporter. The conversion of n-butane increased firstly and then decreased with the increase of Au loading at a range of 0.12%~1.91%. The selectivity to iso-butane increased with increase of Au loading apparently when Au loading was at a low level. When reaction temperature was lower than 400℃, the main reaction on Au/HZSM-5 catalyst was isomerization of pure n-butane. When the temperature was higher than 400℃, the main reactions were dissociation and aromatization. 400℃ was the watershed of dissociation and aromatization under the reaction conditions of micro-scale pulse reaction. Additionally, the composition of mixed butane had certainly influence on the isomerization reaction of n-butane. But the products in the isomerization reaction of n-butane were very rare at proper reaction temperature, showing a metal-acid bifunctional catalytic character. The species of Au+ possibly played an important role in the dehydrogenation and hydrogenation reactions.
Abstract: Ag/TiO2-B2O3-Al2O3 adsorbents with different B2O3 loadings (e.g. 5%~20% (w)) were prepared by impregnation. Static adsorption tests were carried out by contacting the adsorbents with commercial diesel containing 245.36mg(S)/L sulfur at ambient conditions to investigate the adsorption desulfurization activity. The results show that Ag/TiO2-Al2O3 modified by B2O3 exhibits a great enhancement for the adsorption desulfurization activity. When B2O3 (15%) was loaded, 2%Ag/4%TiO2-15%B2O3-Al2O3 (w) could achieve the best desulfurization activity with a saturation capacity of 2.36mg(S)/g adsorbent. This is a significant achievement regarding the desulfurization efficiency, especially for commercial diesel without pretreatment. The effects of B2O3 on the textural properties, crystal structure and surface acidity properties of the adsorbent were studied by N2-physisorption, O2-chemisorption, X-ray diffraction (XRD), temperature-programmed desorption of ammonia (NH3-TPD), Fourier transform infrared spectrometer (FT-IR spectra) and 11B nuclear magnetic resonance (11B-NMR) techniques. Correlating the characterizations with the desulfurization activity, it is found that the adsorption desulfurization activity is well related with the amounts of weak acid sites on the adsorbents. B2O3 modification induces larger amounts of BO4 species and improves the surface weak acidity, resulting in a higher adsorption desulfurization activity.
Abstract: Mesoporous MoO3-ZrO2 composite oxides were prepared by sol-gel method. The influence of the mass ratio of MoO3/ZrO2 on the crystal phase, specific surface area, pore size and morphology characteristics were investigated. The synthesized composite oxides were characterized by XRD, BET, SEM and FT-IR. With FCC gasoline fraction as the raw material, the catalytic activity was evaluated by hydrodesulfurization reaction after the prevulcanization of the composite oxides. The results show that the ZrO2 containing MoO3 had less monoclinic phase than ZrO2 and mainly existed in stable tetragonal phase. The appropriate improvement of the mass ratio of MoO3/ZrO2 were beneficial to the increase of specific surface area and average pore size. The excessive mass ratio of MoO3/ZrO2 depressed the formation of mesopores and produced a new type chemical bond and a small amount of Zr(MoO4)2 crystal phase. When the mass ratio of MoO3/ZrO2 was 30%, the worm structure appeared on the surface of ZrO2, and the desulfurization rate reached its maximum. Thus, the appropriate improvement of the mass ratio of MoO3/ZrO2 could obtain a higher desulfurization rate.
Abstract: One of the thrust areas of research is to find an alternative fuel to meet the increasing demand for energy. Glucose is a good source of alternative fuel for clean energy and is easily available in abundance from both naturally occurring plants and industrial processes. Electrochemical oxidation of glucose in fuel cell requires high electro-catalytic surface of the electrode to produce the clean electrical energy with minimum energy losses in the cell. Pt and Pt based alloys exhibit high electro-catalytic properties but they are expensive. For energy synthesis at economically cheap price, non Pt based inexpensive high electro catalytic material is required. Electro synthesized ZnO-Al2O3 composite is found to exhibit high electro-catalytic properties for glucose oxidation. The Cyclic Voltammetry and Chronoamperometry curves reflect that the material is very much comparable to Pt as far as the maximum current and the steady state current delivered from the glucose oxidation are concerned. XRD image confirms the mixed oxide composite. SEM images morphology show increased 3D surface areas at higher magnification. This attributed high current delivered from electrochemical oxidation of glucose on this electrode surface.
Abstract: Bio-cathode microbial fuel cells (MFCs) were built to treat the aging landfill leachate; the effect of electrode surface area on the aging landfill leachate treatment and electrical performance of MFCs was investigated. The results show that for three sets of bio-cathode MFCs with the ratios of anode area to cathode area being 1:2, 2:2 and 2:1, the stable maximum output voltages are 408, 452 and 396mV, respectively, with the maximum electric power density of 145.73, 237.65 and 136.50mW/m3, the resistance of 350, 200 and 400Ω, and COD removal rate of 21.18%, 20.20% and 22.31%, respectively. After running for 30 days, the concentration of ammonia, nitrate and nitrite nitrogen in landfill leachate is decreased; the ammonia removal rates for the three sets of MFCs are 80.88%, 73.61% and 66.17%, respectively, which is related to the electricity generation of MFCs.
Abstract: This work briefly reveals the process of catalytic oxidation of SO2 and the influences of NH3, NO and O2 on the oxidation behavior based on FT-IR.It suggests that the process of oxidation of SO2: the absorption of SO2 on V2O5 sites occupying its O atom in the form of SO2-3; reaction between absorbed SO2 and O atom in V5+-OH to form an VOSO4-like structure;reoxidation of V4+ to V5+ by O2,promoting the transformation from VOSO4-like intermediate to SO3 and V2O5. NH3 and NO competitively absorb with SO2,suppressing its oxidation behavior. The removal of NOx and the oxidation of SO2 is the relationship of mutual inhibition.
Supervisor：Chinese Academy of Sciences
Sponsors by：Shanxi Institute of Coal Chemistry, Chinese Academy of Sciences Chinese Chemical Society
