Abstract: The gasification reactivity of Shenhua coal char (CC) and Shenhua coal direct liquefaction residue char (RC) with CO2 and steam was studied using a fixed bed reactor. The results show that CC has a higher steam gasification activity than RC, while RC has a higher CO2 gasification activity than CC, which is due to different influencing factors for steam and CO2 gasification. For steam gasification the reactivity of char is mainly affected by coal rank, but for CO2 gasification the reactivity of char is mainly affected by the catalysis of mineral matter.
Abstract: The surface morphology, microstructure, mineral components and structural porosity of the heat treated coal ash at 1300℃and 1400℃ under reducing atmosphere in a tube furnace and the slag from an entrained-flow gasifier with membrane water wall were investigated by using XRD, SEM and EDS. It is found that the surface morphology, microstructure and compositions of the heat treated coal ash are affected remarkably by the treatment temperature and the ash fluid temperature. When the treatment temperature is higher than the ash fluid temperature about 10℃, a lot of crystalline particles are formed in the heat treated coal ash, the surface morphology becomes coarse, and the microstructure is uneven. When the treatment temperature is over the fluid temperature about 100℃, the majority of crystalline particles in the heat treated coal ash are transformed to glassy amorphous phase that is distributed uniformly in the ash. The results indicate that in a simulated reducing atmosphere of the gasifier to investigate the effect of operation temperature on the structure of slag in a tube furnace is feasible.
Abstract: A detailed thermodynamic analysis of the combined coal gasification and coal-bed methane reforming under conditions prevailing those in fluidised-beds has been performed using the Gibbs free energy minimization method. By keeping the adiabatic temperature of the reaction system to 1273K, coal gasification alone is compared with the combined coal gasification and methane reforming in terms of cold gas efficiency, oxygen consumption and product gas H2/CO ratio. The results show that increasing methane feed in the gasification system can improve the cold gas efficiency and reduce the oxygen consumption. The H2/CO ratio of the synthesis gas produced is adjustable. Methane is shown to play in part the role of steam and thus reduce the water consumption in the combined process. The findings of the present analysis testify the advantage of combined coal gasification and coal-bed methane reforming process as an alternative means of coal-bed methane utilisation and provide useful guidelines for potential practical applications.
Abstract: The understanding of sintering temperature of coal ash is of significance for the design and operation of fluidized bed combustion and gasification systems. So the ash sintering for different coal ash samples under different reaction atmospheres was studied by means of a coal ash sintering temperature measuring system based on the variation of the pressure-drop, and the effects of reaction atmosphere and ash composition on coal ash sintering behavior were discussed. The results show that the sintering temperature increases with the ratio of the acidic oxide to the basic oxide in coal ash, and an increment of iron in coal ash will decrease the sintering temperature obviously. The sintering temperature of coal ash under reducing reaction atmosphere is lower than that under oxidizing reaction atmosphere, and the sintering temperature under CO atmosphere is higher than that under H2 atmosphere because an eutectic substance of Na2S-FeS can be formed easily under H2 atmosphere for the coal ash including Fe2O3、Na2O and SO3. The coal ash sintering temperature under typical fluidized bed gasification atmosphere is between that under CO atmosphere and H2 atmosphere, which is closer to the sintering temperature under CO atmosphere.
Abstract: Nine different fusion temperature coals were selected, and the relationship between ash fusion temperature and ash mineral composition and content were studied by using XRD. The mineral transformation of typical coal ashes in reducing atmosphere was also investigayed. The results show that the mineral phases of coal ashes which are ashed at 815℃ mainly include quartz, anhydrite, hematite, portlandite, lime and potash feldspar. Higher anhydrite and hematite content and lower portlandite content would result in lower ash fusion temperature. As the heating temperature increases, the content of quartz, anhydrite and portlandite in coal ash decreases in reducing conditions and some new mineral phases are formed. Mullite is formed, which leads to higher ash fusion temperature. However, the formation of anorthite and hedenbergite at 1100℃ in the heating process is the main reason for the ash melting temperature lowing.
Abstract: Effects of coal characteristics including rank, macerals, coal ash and ash content on combustion catalyzed by CeO2 were investigated using demineralized coals and coal ash. The results show that coal rank has remarkable effect on catalytic combustion. The higher the coal rank, the more decrease in ignition temperature of its demineralized coal. There is no obvious effect of CeO2 on combustion of Shenhua coal macerals. Coal ash has some catalytic effects on combustion coal organics. The catalytic effect of mixture of ash and CeO2 is more than that of ash or CeO2 independently, showing they have interactions for catalytic anthracite combustion. Effects of ash content on catalytic combustion were investigated by synthesized coal, indicating catalytic effect was the best with 6% ash content. When coal ash content is over 18%, CeO2 has some inhibiting effects on anthracite combustion. CeO2 only has catalytic effect on combustion of higher rank coal with lower inorganic content.
Abstract: In comparison with the supreme commercial paving asphalt modifier TLA, three heavy products derived from the co-processing of coal with FCC slurry and one heavy product from a bench scale continuing coal liquefaction process have a similar modification ability to the same base asphalt (Binzhou 90#). Two modified asphalts (one by coal tar pitch and another one by the product from the co-processing) are excluded due to the dissatisfaction on ductility. FT-IR analysis shows that the addition of coal-derived heavy products does not form any new functional group, but results in a new distribution of the functional groups which can improve the behavior of the base asphalt. The addition of TLA can increase C-O and S-O functional groups, which should be favorable for the interaction of asphalt binder and limestone. The higher aromaticity of the coal tar pitch may inhibit its mixing and interaction with the base asphalt. Two unsatisfied modified asphalts have a lower colloidal index (CI). The difference between the theoretically calculated CI and the experimental CI of modified asphalt indicates that the chemical reaction may occur between the base asphalt and the additives.
Abstract: Inert solvent was selected to extract corresponding extractives from different kinds of biomass. Pyrolysis of the extractives was studied on thermogravimetric analyzer coupled with Fourier Transform Infrared spectroscopy (TG-FTIR). The influence of extractives on biomass pyrolysis was also discussed. The results show that extractives have distinct differences in composition and product distribution due to the different amount of guaiacyl and syringyl units in lignin component. Manchurian ash contains more methanol and methane caused by the decomposition of phenols at high temperature. Compared with raw biomass, extracted biomass has higher activation energy and begins to release main products earlier; the yield of water, CO2, CO and aldehydes increases, while acids and alkanes decrease.
Abstract: The present work focused on the effect of pyrolysis temperatures on the yield of bio-oil from fast pyrolysis of straw in a fluidized bed reactor. The chemical compositions of biooil, obtained at 300℃~600℃ coupling with condensation at 22℃ or －4.4℃, were examined by GC/MS and FT-IR. The results show that the highest bio-oil yield of 43.1% is obtained at 400℃. The condensation temperature significantly affects the quality of bio-oil. Lower condensation temperature facilitates increasing of its heat value and the content of organics, and consequently decreasing the concentration of water. Based on the present result, the subsequent technology could be flexibly set up to meet the objective requirements and obtain operation parameters to optimize the pyrolysis process.
Abstract: Biodiesel fuel, chemically consisted of fatty acid methylester (FAME) produced by methanolysis of natural triglycerides such as animal fats and vegetable oils, is a kind of biomass energy. KF/CaO was used as solid base catalyst for transesterification to produce biodiesel fuel with ultrasound as an auxiliary means. Compared with mechanical stirring, ultrasound treatment is an effective method to increase the yield of biodiesel and shorten the reaction time. By single factor method, the optimization of reaction conditions has been studied with ultrasound. The results show that the reaction conditions are as following. The weight ratio of catalyst to oil is 3%, and molar ratio of methanol to oil is 12. The sound frequency is 20kHz with intensity of 1.01W/cm2. Under the above conditions, the yield of biodiesl reaches 99.6% at 65℃ in 1h.
Abstract: The influence of operating severity on the heavy components of oil vapor, especially the distillate above 550℃, resin and asphaltene in the oil slurry, were investigated in a technical scale riser FCC pilot plant. A correlation between the operation severity and the distribution of heavy components and products was established. The results show that with the increase of operation severity, the content of the distillate heavier than 550℃ and the resin and asphaltene in the oil slurry are decreased obviously. Up to a certain limit, the yield of light oil changes little with the increase of the operation severity; however, it may decrease rapidly when the operation severity exceeds this limit. The operation severity correlation obtained in this work may provide proper guidance for controlling the operating condition to obtain a desirable product distribution and preventing RFCC disengager from coke formation by decreasing the content of heavy compounds in the oil vapor.
Abstract: The acid modified kaolinite and Mo supported on acid modified kaolinite were used as the adsorbents for VO-OEP in cyclohexane. The adsorption behavior as well as adsorption mechanism were investigated thermodynamically. The results show that the adsorption process follows the Langmuir′s isotherms, indicating a monolayer VO-OEP adsorbed on the modified kaolinite. The adsorption of VO-OEP on the modified kaolinite is exothermic in nature with the adsorption heat exceeding 40kJ/mol, which illustrates that chemical bonds are formed between VO-OEP and the modified kaolinite by adsorption.
Abstract: NiMoP/Al2O3 catalysts with different phosphorus contents were prepared by co-impregnation method and characterized by temperature-programmed reduction (TPR), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), and hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) tests. The effect of phosphorus content on the active phase structure of these catalysts was investigated. The TPR results indicated that with the increase of the phosphorus content in the catalysts, the amount of tetrahedral Mo species was decreased, while that of octahedral Mo species was increased. The HRTEM results showed that the number of stacking layers of MoS2 nanoparticles increased with the phosphorus content, which was effective to enhance the hydrogenation selectivity of the catalysts. The fraction of available Mo dispersion (fMo) and the number of active phases in the catalysts increased with increasing phosphorus content to P/MoO3 = 0.09; beyond that, a reverse trend was observed. High HDS and HDN activity were obtained over the catalyst with the phosphorus content of P/MoO3 = 0.09, which could be attributed to its high concentration of Mo atoms on the catalyst surface, high efficient promotion rate (PR) and high promoter ratio (Ni/Mo). However, excessive phosphorus content may deteriorate the performance of NiMoP/Al2O3 catalysts due to the aggregation of active components.
Abstract: Catalytic oxidation of carbazole (CAZ) was investigated using oil-soluble t-butyl hydroperoxide (TBHP) as oxidant and Mo(VI) complexes as catalyst. The influences of various factors on CAZ conversion were probed including ligand, supporter and other metals Ni and Co involving. The results show that without supporter molybdenum acetylacetonate (Mo(VI)) has higher activity than MoO3 because of its solubility in hydrocarbon. All supporters, Al2O3, weakly acidic cation exchange resin (D113) and weakly acidic chelating cation exchange resin (D751), can promote the activity of MoO3. Incorporation of Ni and Co metals can reduce the activity of MoO3/Al2O3. It is also found that in the presence of dibenzothiophene (DBT), TBHP/MoO3/D113 presents a higher oxidation selectivity of CAZ, while TBHP/MoO3/D751 has a similar oxidation activity to CAZ and DBT. The structure of CAZ oxidation product was speculated according to the spectrum data.
Abstract: Supported Au/TS-1 catalysts were prepared and characterized by XRD, SEM and TEM. Their performance in the catalytic oxidation of nitrogen monoxide was evaluated and the effect of reaction conditions on NO conversion was examined. The results indicated that Au granules are successfully loaded on the molecular sieve TS-1 and the catalysts Au/TS-1 obtained exhibit good crystallinity. The catalysts Au/TS-1 exhibit excellent performance in the selective catalytic oxidation of nitrogen monoxide at low temperature. Over the catalyst with an Au loading of 1.0%, with the molar fractions of NO and O2 in the feed being 1×10-3 and 0.1, respectively, and under a space velocity (GHSV) of 5000h－1, the conversion of NO reaches 55% at 180℃ and 78% at 260℃.
Abstract: The nano TiO2/ceramic supported V2O5-WO3 catalysts (V2O5-WO3/TiO2(C)) were prepared. Their poisoning by alkali metal (K, Na) impregnated and regeneration were investigated. The catalysts were characterized by XRD, FT-IR, H2-TPR, XPS measurements. The results indicated that the catalytic activity is decreased by adding alkali metals; potassium is more poisonous than sodium. FT-IR results suggested that Lewis acid sites in the catalysts are active in the de-NOx reaction. H2-TPR and XPS analysis revealed that potassium leads to a decrease of the surface redox ability, which may reduce the oxygen adsorption and the SCR activity of the catalyst. Washing with water can not get back the catalyst activity, suggesting that potassium is not physically deposited on the catalyst surface. The activity of the poisoned catalysts can be well regenerated by washing with sulfuric acid at high temperature.
Abstract: FT-IR spectra of different kinds of sulfides adsorbed on CeY zeolite were collected. Based on that, the effect of olefins (with 1-octene, 1,5-hexadiene, and cyclohexene as model compounds) in FCC gasoline on the desulfurization performance of CeY were investigated. The results revealed that a ring-opening catalytic reaction occurs after the sulfides are adsorbed. As compared with alkyl thiophenes, benzo thiophenes are more stable. The strong interactions between the double bond in alkenes with the Ce cation in CeY lead to the formation of π-complexes through the σ—π electron donations, which competes with the SM function between thiophene and CeY. The amounts of polymers formed on the CeY surface increases with the concentration of alkenes, which may occupy the active sites and clog the pores in CeY; this will reduce the adsorptive selectivity for removing thiophene from the model fuel.
Abstract: The effects of water on the stability of the catalyst and the product distribution were investigated through controlling the amount of water dehydrated from methanol or using HZSM5 pretreated by hydrothermal method at the analogous atmosphere of gasoline synthesis in two-stage process（360℃， 2MPa）. Physicochemical properties of the zeolite were characterized by XRD, BET, FT-IR, SEM, and NH3-TPD. The results showed that HZSM-5 pretreated by hydrothermal method had smaller crystal size, more mesoporous, and moderate acid sites, which in all result in the enhancement of gasoline yield and the selectivity to iso-paraffins. The steam generated during methanol dehydration led to the deactivation of strong acid over HZSM-5 zeolite.
Abstract: A fibrous CD501 methanol synthesis catalyst was prepared by a novel coprecipation method and characterized by SEM, TEM, XRD and BET. For Cu/ZnO/Al2O3/ZrO2+γ-Al2O3 bifunctional catalyst which is a mixture of CD501 and γ-Al2O3, the catalytic performance for dimethyl ether (DME) synthesis was evaluated in a slurry reactor. The characterization showed that the CD501 catalyst had a larger specific surface area and a higher Cu/Zn dispersion than those of a commercial catalyst (COM) and LP201 catalyst. For the DME synthesis in a slurry reactor using CD501+γ-Al2O catalyst, the CO conversion is twice as that on the COM+γ-Al2O3 or LP201+γ-Al2O3 catalyst. After 270h test, the CO conversion decreased from 61% to 57%, the space time yield of DME decreased from 0.54g/(g·h) to 0.48g/(g·h), respectively. Compared with COM catalyst, the stability of the present reported catalyst was much improved.When reaction temperature is 250℃, pressure 4.0MPa, space velocity 3000mL/(g·h), and H/C mol ratio 1.0, the CO conversion reached 61%, and space time yield of DME reached 0.54g/(g·h).
Abstract: Manganese oxide octahedral molecular sieves (OMS-2) were synthesized by oxidizing MnSO4 with KMnO4 and then doped with Ce. The structure and oxidation activity of the catalysts were characterized by XRD, N2 adsorptiondesorption, TEM, FT-IR, Uv-vis, O2-TPD, H2-TPR and XPS techniques. The catalytic activity for dimethyl ether (DME) combustion was also evaluated. The results showed that the highly-dispersed amorphous CeO2 exited when Ce-doping was low. However, the independent CeO2 formed when Ce-doping exceed 10%. XPS results show that the doped-Ce can improve the lattice oxygen of the catalyst. O2-TPD and H2TPR characterization show that the Ce-OMS-2 catalysts have abundant facile lattice oxygen and can be easily reduced. Ce-OMS-2 display excellent performance in DME catalytic combustion, with a start-off temperature of 160℃ and a complete temperature of 170℃. CO2 and H2O are the only reaction products detected. The used catalyst keeps the same crystalline as the fresh, and there is no carbon deposition detected over the used catalyst.
Abstract: For studying the feasibility of ethanol being used in SOFC, citric acid solgel is used to prepare the Ni-ZnO-ZrO2 catalyst and Ni-ZnO-ZrO2-YSZ（Yttria-stabilized zirconia）anode is prepared by mechanical mixing. The cells of Ni-ZnO-ZrO2-YSZ/YSZ/LSM（La0.85Sr0.15MnO3）and Ni-YSZ/YSZ/LSM are made on the YSZ electrolyte by coating method. Power generation was tested and compared between both anodes using ethanol as fuel at different conditions including various temperatures of evaporator and cell, and flow rates of ethanol vapor. The surfaces of the two electrodes were characterized by SEM after test. The results showed that the performances of the cell with Ni-ZnO-ZrO2 -YSZ anode are better than those of the cell with Ni-YSZ anode, and Ni-ZnO-ZrO2-YSZ anode has a good ability in resistance to carbon formation at anode.
Abstract: The surface structures of Fe3O4(111), (110) and (001) have been studied at the level of density functional theory. It is found that there are two most stable Fe3O4(111) surfaces in close energy and terminated with the exposed tetrahedral and octahedral iron layers. Both Fe3O4(110) and Fe3O4(001) surfaces have two surface terminations in close energy. The computed results agree well with the experiments, and explain reasonably the observed diversity and complexity of the experiments. The computed surface free energies indicate that (111) is less favourable thermodynamically than (110) and (001), and the formation of (111) should be kinetic controlled.
Supervisor：Chinese Academy of Sciences
Sponsors by：Shanxi Institute of Coal Chemistry, Chinese Academy of Sciences Chinese Chemical Society
