Abstract: Extensive research has shown that coal has an extractable small molecular compound, which was associated with non-covalent bonding coal molecules. In addition, the reactivity of coal extract and residue is different. In this work, a bituminous coal was acid washed and extracted by pyridine to destroy the electrostatic interactions and hydrogen bonds. The pyrolysis behavior of the extracts and residue was studied by thermogravimetry (TG) and a fixed bed reactor. The H/C atomic ratio for the pyridine extract was significantly higher than that of raw coal, indicating hydrogen-rich components. The pyridine extract (E1) gave a higher tar yield of 44.41%, as well as more gas, while the tar yield of residue (R1) was lower than raw coal in an N2 atmosphere. However, the residue gave more than two times the amount of tar under H2 than that of N2 because developed porous structure was formed by pyridine extraction, which would facilitate hydrogen diffusion into the pore structure and reduce the polycondensation reaction.
Abstract: The integrated mild-liquefaction and carbonization experiments of Hongliulin coal were conducted at 430-600 ℃, and distributions and physico-chemical properties of the obtained products were investigated. The results show that the yields of semi-cokes, organic liquid products and n-hexane soluble organic products were up to 40.64%-53.02%, 30.89%-36.98% and 29.74%-33.28%, respectively. The increasing carbonization temperature in the relatively low temperature range was favorable for the elevated yield of n-hexane soluble organic products, while at relatively high temperature presenting an opposite one. The semi-cokes obtained at 430 ℃ presented a strong caking property, while those at 550 ℃ showed no caking property, and the content of their volatile matters decreased to about 10%. It is suggested that the produced semi-coke could be directionally utilized as blending coal in coking or smokeless fuel by adjusting carbonization temperature.
Abstract: During coal pyrolysis and gasification, the minerals in coal undergo various transformations, which affects coal conversion and characteristics of coal ash obviously. Carbothermal reduction of Si-Al-Fe-Ca quaternary system in high-silica coal under different temperature was investigated. Composition of products obtained was analyzed by X-ray diffraction (XRD) and field emission scanning electron microscope-energy dispersive spectrometer (FESEM-EDS) technology. The results show that Fe2O3 plays a positive role in carbothermal reaction of silicon-bearing minerals, which could effectively improve activity of Si. On the contrary, CaO reacts with Al2O3 and SiO2 to form dense Ca-Al-Si eutectic, mainly CaAl2Si2O8, at lower temperature, covering surface of the reactant, which hinders the carbothermal reaction of silicon-containing minerals. With increasing temperature, CaAl2Si2O8 reacts with graphite to generate SiC, CaAl4O7 and CaSiO3. The related thermodynamic calculations are in accordance with the experiment results.
Abstract: In this work, the influences of two industrial fluxes (i.e. limestone and clay) and their composite flux on ash fusion and viscosity temperature characteristics of Shanxi typical high-alumina coals were explored, respectively. The results indicated that flow temperature of coal ash decreased with increasing additive amount of flux. Moreover, limestone exhibited a better flux effect than clay, among which the flux effect of composite flux was more obvious than that of the single fluxes. It was also found that limestone could significantly reduce the tcv of coal ash slag and clay could promote the slag type transformation towards glassy slag. Compared with single fluxes, composite flux exhibited synergistic effect on both the significant reduction of tcv and the promotion of slag type transformation. For Shanxi typical high-alumina Liangdu coal, when total amount of composite flux was 4% (2% limestone+2% clay), not only the slag transformed into glassy slag, but also tcv of the slag decreased 133 and 222 ℃ compared with single flux limestone(2%) and clay (6%), respectively. Minerals analysis results confirmed the fluxing principle of different fluxes. After the addition of composite flux, Shanxi high-alumina coals could meet the requirements of industrial entrained-flow gasifier.
Abstract: The models of montmorillonite, kaolinite, calcite and gypsum as the mineral substances in oil shale were built by using Materials Studio 2017 software; the adsorption of CH4 and CO2 on these mineral substances was then simulated by the GCMC and MD method. The results illustrated that the adsorption capacity of CH4 and CO2 on four mineral substances under the same temperature and pressure follows the order of montmorillonite > kaolinite > gypsum > calcite. The adsorption of single component CH4 and CO2 is in accordance with the Langmuir isotherm and the adsorption heats for both CH4 and CO2 on four mineral models all are less than 42 kJ/mol, suggesting that the adsorption belongs to physical category. With the increase of temperature, both the adsorption capacity and adsorption heat are reduced; there is a positive correlation between the adsorption heat and adsorption capacity for the CH4 and CO2 molecules.
Abstract: Effects of atmosphere, mixing ratio and residue carbon on ash fusion characteristics of biomass and bituminous coal were investigated. The pine sawdust ash was mixed with Wuhai bituminous coal ash at different mass ratios. The ash fusion temperatures (AFTS) of the mixed ash in different atmospheres were determined by ash-melting point measuring device. X-ray diffraction ray was used to investigate the reason for AFTs variation from the perspective of minerals evolution. The result shows that AFTs of mixed ash in weak reducing atmosphere is lower than that in oxidizing one due to formation of fayalite and hercynite. In addition, the difference in AFTs under reducing and oxidizing atmosphere is related to the content of Fe in the mixed ash. The increment of pine sawdust ash favors generation of gehlenite, akermanite and leucite ect., which can be classified as low temperature eutectics and help to reduce the AFTs of mixed ash. Moreover, the AFTs of the mixed ash increase initially and decrease afterwards and then increase again with the increment of residue carbon content in coal ash, due to formation of Fe-C eutectic (FexCy), local reducing atmosphere and skeleton action of residue carbon.
Abstract: The effects of paper mill residues (delinking sludge, paper mill sludge, municipal sewage sludge) addition on slagging tendency of wheat straw were investigated using ash melting point test system, X-ray fluorescence (XRF) and powder X-ray diffraction (XRD). The differences between other 4 common additives were also discussed. The results show that addition of delinking sludge and paper mill sludge behaves better than municipal sewage sludge in blending range of 3% to 10%, while softening temperature of wheat ash tends to get the highest value when adding 5% paper mill sludge. Along with the blends increasing, Al2O3 plays an important framework structure modification role while adding paper mill sludge. While generation of feldspar such as orthoclase and anorthite takes place, the softening temperature decreases. In addition, silicon aluminum garnet is more likely to form to enhance the fusion characteristic temperate while adding delinking sludge. On the contrary, formation of high melting point material(CaSiO3)inhibits low melting silicate by adding paper mill sludge. Components analyses indicate that crystal structure of SiO2 is changed along with municipal sludge added. Sludge used as anti-slagging additives is promising.
Abstract: The modified CoMo/γ-Al2O3 catalyst was prepared by addition of ethylene diamine (EN), ethanolamine (EA), ethylene glycol (EG) or malonic acid (MA). The effect of four bidentate molecules with different coordination groups on the dibenzothiophene HDS was compared. And the catalytic activity is determined in the sequence of CoMo (EN) > CoMo (EA) > CoMo (EG)≈CoMo (MA) > CoMo. For all catalysts, the direct desulfurization route is dominated, but with the increase of reaction temperature, the desulfurization by hydrogenation route become more apparent. Chelating agents facilitate the HDS reaction through hydrogenation route. CoMo (EN) catalyst presents the highest hydrogenation ability. The catalysts were characterized by UV-vis, EA, XPS and HRTEM. The results show that NH2 group has a strong complexing interaction with Co2+. COOH group mainly has an electrostatic interaction with cobalt ion. Meanwhile, OH group hardly interacts with Co2+. It is noted that the HDS activity is directly related to the interaction between coordinating groups and Co2+. The combination of coordinating molecules with Co2+ leads to the effective formation of Co-Mo-S active center, and the carbonization of chelating decreases the interaction of the support with active phases, facilitating the formation of type Ⅱ active phases which has a higher intrinsic catalytic activity.
Abstract: The NiWO4 nanoparticles were synthesized by hydrothermal method. The supported catalysts NiWO4/g-C3N4 were prepared by a simple mixing-calcination method. XRD, FT-IR, EDS, SEM, BET and XPS were used to characterize the morphology and structure of NiWO4/g-C3N4. The prepared NiWO4/g-C3N4 was used as catalyst, hydrogen peroxide as oxidant, 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid ([BMIM]BF4) as extractant for oxidative desulfurization. The effects of catalyst loading, the amount of hydrogen peroxide, ionic liquid and catalyst, reaction temperature, reaction time, and different sulfur compounds on desulfurization efficiency were studied. The desulfurization rate can reach 97.35% at the optimum reaction conditions:5 mL of model oil, 0.2 mL of hydrogen peroxide, 1.0 mL of [BMIM] BF4, 0.03 g of NiWO4/g-C3N4, 80 ℃ of reaction temperature and 140 min of reaction time. The results showed that NiWO4/g-C3N4 had good catalytic stability, and the catalytic activity was not significantly reduced after 5 repeated reactions.
Abstract: Al-ITQ-13 zeolites with different SiO2/Al2O3 molar ratios were synthesized by using seeds in the gel and characterized by XRD, SEM, N2 physisorption, MAS NMR and NH3-TPD. The effect of SiO2/Al2O3 molar ratio on the catalytic performance of Al-ITQ-13 in the conversion of methanol to propene (MTP) was investigated in a fixed-bed micro-reactor. The results showed that the Al-ITQ-13 zeolites with different SiO2/Al2O3 molar ratios are similar in their textural properties; however, the amount and strength of acid sites decrease with the increase of SiO2/Al2O3 molar ratio. Moreover, the SiO2/Al2O3 molar ratio has a significant influence on the catalytic behavior of Al-ITQ-13 in MTP. As the hydrogen transfer and aromatization reactions were suppressed over the Al-ITQ-13 zeolite with high SiO2/Al2O3 molar ratio, with the increase of SiO2/Al2O3 molar ratio, the selectivity to propene and butene is increased at the expense of the selectivity to propene; that is, with the increase of SiO2/Al2O3 molar ratio from 137 to 309, the selectivity to propene is increased from 46.04% to 55.52% and meanwhile, the propene/ethene ratio is increased from 3.39 to 6.57.
Abstract: The effect of SO2 on the low-temperature SCR activity and the thermal reduction regeneration for holmium-modified Fe-Mn/TiO2 catalyst were investigated by activity assessment and various characterization methods. The deposition of ammonium sulfate ((NH4)2SO4) on catalyst surface and the sulfuration of active component (MnSO4) were proved to be the main causes for the deactivation in the presence of SO2. The catalyst Fe0.3Ho0.1Mn0.4/TiO2 exhibited superior SO2 durability when the concentration of SO2 was lower than 0.04%, and the catalytic activity could markedly recover with the termination of sulfur-poisoning source. The deactivation behavior was irreversible when the concentration of SO2 was increased to 0.1% but the poisoned catalyst could be regenerated after thermal reduction (350 ℃) for 60 min by 5% NH3. The microstructure and physicochemical properties could be significantly restored after the thermal reduction regeneration. Moreover, the NOx conversion could return to about 80%.
Abstract: Sol-gel and impregnation methods were used to prepare the Fe/Ag/Al2O3 catalysts supported on the monolithic cordierite with different Fe/Ag loading ratios. The catalytic performance to reduce NO with C3H6 was evaluated in a one-dimensional electrically heated temperature programmed ceramic tubular reactor in simulated flue gas atmosphere at 200-700 ℃. The results show that the NO reduction efficiency on 7.2Fe/1.9Ag/20Al2O3/CM with C3H6 is more than 90% and reaches about 100% at the temperatures of 500 ℃ and 550 ℃ respectively. Iron can effectively improve the ability of Ag/20Al2O3/CM catalysts to resist SO2 and H2O in flue gas. When SO2 and H2O are 0.02% and 8% in the flue gas, the NO reduction efficiency is almost not influenced on 7.2Fe/1.9Ag/20Al2O3/CM at 500 ℃. The 90% NO reduction efficiency is maintained during 6 h without decrease. However, the catalytic activity of 2Ag/20Al2O3/CM without iron modification is strongly influenced by SO2 and H2O in the flue gas. The NO reduction efficiency on Ag/20Al2O3/CM decreases rapidly from about 70% to 46% and 25% respectively, when the SO2 and H2O are 0.02% and 8% in the flue gas. The results of XRD and SEM of the catalyst show that AgFeO2 and Fe3+ are formed in the 7.2Fe/1.9Ag/20Al2O3/CM catalyst after the modification by iron, and the surface of the catalyst become loose and porous, forming Fe3O4-based needle-like and flaky crystals. H2-TPR results show that 7.2Fe/1.9Ag/20Al2O3/CM has better reduction properties than Ag/20Al2O3/CM in the wider temperature range. Pyridine adsorption Infrared Spectroscopy (Py-FTIR) experimental results show that Fe increases the Lewis acid sites in the catalyst surface.
Abstract: HZSM-5(core)/SAPO-11(shell) composite molecular sieves were hydrothermally synthesized by crystallization of SAPO-11 outside HZSM-5 surface. After loading 10% Cr2O3, the pore distribution, acidity, and catalytic activity of the composite supported Cr2O3 in the transformation of liquefied petroleum gas (LPG) to ethene and propene were investigated. The results showed the HZSM-5 surface was coated with SAPO-11 microcrystalline of different thicknesses. With the increase of crystallization time, the shell thickness of the composite molecular sieves is increased; the mesoporosity and acidity can then be regulated by controlling the shell thickness. The composite supported Cr2O3 exhibits superior activity in the transformation of LPG to olefins than the single molecular sieves or mechanically mixed ones. The Cr2O3 catalyst supported on the composite by crystallization for 12 h gives the highest activity and selectivity to the target products; the feed conversion and the selectivity to ethene and propene are 42.63% and 65.89%, respectively, while the selectivities to CH4 and C5+ are 6.32% and 15.48%, respectively.
Abstract: Mo/HZSM-5, Mo-W/HZSM-5 and W/HZSM-5 catalysts were prepared via a conventional impregnation method. The catalysts were characterized by means of XRD, BET, Py-FTIR, H2-TPR, XPS, TEM, NH3-TPD, TPO, TG and Raman, and were evaluated in methane non-oxidative dehydroaromatization(MDA). Compared with Mo/HZSM-5, the CH4 conversion, aromatics yield and catalytic stability were improved by W addition for Mo-W/HZSM-5 in MDA reaction. H2-TPR and XPS results indicated that the octahedral (WO6)n- groups existed in Mo-W/HZSM-5 were more easily reduced to W4+-containing species in MDA reaction in comparison with W/HZSM-5, and W4+-containing species was correlated with the high MDA activity. At the same time, it is found that graphitic-like coking is the main reason of catalyst deactivation for Mo/HZSM-5, and this coking over Mo-W/HZSM-5 catalyst can be inhibited by W addition during MDA.
Abstract: A group of multi-functional xCuyNi-ABZ catalysts supported on all-silicon Beta zeolite were prepared by an incipient wetness impregnation method. The xCuyNi-ABZ catalysts were characterized by a variety of techniques to obtain the information of their structures, the effect of different amounts of Cu and Ni active sites and understanding the reaction pathway. Compared with the traditional SiO2 supported catalyst, the 2.5Cu2.5Ni-ABZ catalyst exhibited very good catalytic performance for the ethanol steam reforming, including 100% conversion of ethanol, high 67.23% H2 selectivity (67.23%) and low by-product selectivity (CO=4.14%, CH4=5.65%) at 450 ℃ due to the synergistic effects of Ni and Cu. The Cu sites preferentially facilitate the dehydrogenation of ethanol at the initial reaction step, and the Ni metal catalyzes subsequently dissociation of the C-C bond. With increase of reaction temperature, H2 and CO2 selectivity are progressively increased together with the significant decline of CO and CH4 selectivity, which indicates that the dominant reaction is steam acetaldehyde reforming. This phenomenon suggests that there is a temperature-related competition between acetaldehyde decomposition and acetaldehyde steam reforming reaction. Moreover, the presence of Cu promoted the water-gas-shift reaction. The 2.5Cu2.5Ni-ABZ catalyst possesses good anti-sintering ability and anti-carbon deposition properties.
Abstract: Mesoporous CuCe0.75Zr0.25Ox composite was prepared by a simple sol-gel method with environmentally benign bacterial cellulose (BC) as a pore former and characterized by TG/DTG, N2 adsorption-desorption, XRD, H2-TPR, O2-TPD and Raman; its catalytic activity in the degradation of toluene at low temperature was investigated in a fixed-reactor. The results indicated that BC with ultra fine three-dimensional networks and excellent compatibility is beneficial to the formation of gel with nitrate solution, to prepare the mesoporous catalyst. The catalyst performance of CuCe0.75Zr0.25Ox composite is significantly affected by the gel-form and gelling temperature during the preparation process. Over the ACCZ-70 catalyst prepared by alcohol gelling at 70 ℃, the temperature for a complete degradation of toluene (T100) reaches 205 ℃, much lower than those reported in open literature; the excellent activity of ACCZ-70 is ascribed to its high reducibility at low temperature and high concentration of oxygen vacancies (0.81). In addition, adsorption phenomenon was observed in the range of 120-140 ℃ during the toluene degradation over WCCZ catalysts prepared by water gelling.
Supervisor：Chinese Academy of Sciences
Sponsors by：Shanxi Institute of Coal Chemistry, Chinese Academy of Sciences Chinese Chemical Society
