Abstract: The oxidative carbonylation of methanol and ethanol to asymmetric methyl ethyl carbonate (MEC)catalyzed by CuCl coordinated with Schiff base ligands has been studied. A thermodynamic analysis of this process was carried out to discuss the possibility. The equilibrium constant of the main reaction at 298.2 K is 2.39×1080, so the possibility of this reaction is high. The effects of volume ratio of methanol to ethanol, molar ratio of 1,10-phenanthroline(phen)to N-methylimidazole(NMI), temperature, pressure on the conversion of methanol, ethanol and the yield of methyl ethyl carbonate have been investigated. CuCl/phen/NMI catalytic system was found to be active in the ox-idative carbonylation of methanol and ethanol to asymmetric methyl ethyl carbonate. When the reaction was carried out for 2 h at 393 K and 2.4 MPa (CO+O2) in the MeOH/EtOH system, with CuCl 0.20 molL-1, n(CuCl)∶n(phen)∶n(NMI) =1∶1.25∶1.25, and the ratio of vMeOH/vEtOH =2∶8, the conversion of methanol and ethanol are 44.3% and 22.3%, 17 and 9 times higher than that of CuCl system. The yield of MEC was 10.4%, which is increased about 74 times. The mechanism of synthesis of asymmetric carbonate was also discussed in detail.
Abstract: The vapor pyridine adsorption isotherms of coal were investigated using several coals and a model compound(WK11 ion exchange resin and its Na and Ca types) at the temperature of 30℃～60℃. The results indicated that pyridine could disrupt weak hydrogen bonds of original WK11 to form strong pyridine-COOH hydrogen bond, and swell WK11 structure. However, there were a very small amount of adsorption and a very low swelling ratio for Na and Ca type WK11s because of no hydrogen bond formation. There were two different kinds of pyridine adsorption behaviors at low pressure for four coals because of the difference of coal structure. The total pyridine adsorption amount of coals was not only dependent on the hydrogen bonds formed during adsorption process, but also influenced by other kind of specific interaction especially for high rank coals.
Abstract: Modes of occurrence of Pb, Cr, Co, Ni, V in Tieling raw coal and two char samples were determinedusing density fractionation, demineralization and sequential chemical extraction methods. Volatilization behaviors of Pb, Cr, Co, Ni and V were investigated during pyrolysis of Tieling coal in a fluidized-bed reactor at temperatures ranging from 500 ℃ to 900 ℃. Pb, Cr, Co, Ni, V in Tieling coal are mainly associated with mineral matters such as silicates, sulfates, sulfides, and about 40%～60% of them are associated with alumino-silicate mineral matters. Lead associated with carbonates and organic bonded ion exchangeable forms has already decomposed below 600 ℃. Forms of Pb, Cr, Co, Ni, V associated with sulfates and sulfides are unstable, whereas the transformation behaviors of them are different. Thermally stable phases of Cr and V are formed under high pyrolysis temperatures. In the temperature range studied, Pb belongs to semi-volatile elements, while Cr, Co, Ni and V belong to non-volatile elements.
Abstract: Coal reburning is a successful advanced technology for reducing NOx emissions from utility coal-fired boilers. In this work, various rank coals were employed as reburning fuel, the effects of reburning fuel ratio, reacting zone temperature, excess air, residual time and coal fineness on NOx reduction efficiency were experimentally investigated by using an one-dimension drop-tube furnace. The experimental results show that the coal with high volatile content can reduce NOx more effectively. For the same coal, in order to achieve high NOx reduction efficiency, the finer coal finess and suitable residence time of the reburning zone are required. The minimum burn-out height has been put forward to evaluate the right location of the reburning coal injection ports to get a higher carbon burn-out and higher NOx reduction efficiency.
Abstract: A series of SM (Shenmu) partially gasified chars were prepared in a micro-scale fixed-bed. The regasification kinetics of these partially gasified chars for different atmosphere was analyzed by a thermobalance. Results show that the regasification kinetic parameters of partially gasified chars are related with gasification conversion of coals. For gasification in steam, the regasification activation energy, preexponential factor and effect of the pressure of steam on the gasification rate decrease with the increase of gasification conversion, but for gasification in CO2, the regasification activation energy and preexponential factor increase, the effect of the pressure of CO2 on the gasification rate decreases. It is important to point out that the compensation effect exists between activition energy of partially gasified chars and preexponential factor during gasification regardless of atmospheres.
Abstract: This paper presents the distribution characteristics of beryllium in Chinese coals based on 1018 samples from different geological ages and regions all over the country. By means of float-sink experiments and maceral analysis for 10 Chinese coal samples and by the introduction of Solari model, the modes of occurrence of beryllium in coal are studied. The results show that there are relatively remarkable differences among distribution and occurrence of beryllium in coals from different ages and regions in China. Taking account of the differences of coal resources in different regions, the weighted average concentration of beryllium in Chinese coals is calculated. The result shows that the average content of beryllium in Chinese coals is lower than that in the world. In general, the modes of occurrences of beryllium in macerals are complex but for most coals in China, beryllium is mainly distributed in inertinite and clay minerals and the calculated content of beryllium in vitrinite is lower. It can be anticipated that beryllium in most Chinese coals is difficult to be removed during coal preparation due to its high organic affinity.
Abstract: 7 typical Chinese coal samples were extracted by NMP/CS2 system at around 90 ℃ by Soxhlet method. Compared with results from NMP, a higher coal extraction rate was acquired when NMP+CS2 solvent system was adopted. Except for anthracite, above 20% extraction rate of other coals was acquired, particularly 41% for long flame coal. By using the method of retention index of coal extracts analysis by HPLC, it is found that the polar part with less than six-carbon numbers in coal is the active site for coal reactivity, and the inert site belongs to the aromatic hydrocarbon derivation with 3 aromatic rings.
Abstract: Scrap tires were pyrolysed in a pilot-scale kiln reactor in the temperature range of 450 ℃～650 ℃ and properties of the naphtha fraction of the derived oils were analyzed. In separating the naphtha through distillation, it was found that the naphtha yield increased explicitly with increasing pyrolysis temperature and reached a maximum of 40.48% at 600 ℃, then decreased at the increased temperature of 650 ℃. Qualitative and quantitative analysis of the composition of pyrolytic naphtha was carried out on GC and GC-MS. It was shown that the pyrolytic naphtha was highly aromatic. The content of aromatic hydrocarbons kept increasing with pyrolytic temperature and amounted to over 80% in the pyrolytic naphtha with pyrolytic temperature higher than 550 ℃. BTX-aromatics, including benzene, toluene, styrene and xylenes, were the main aromatic hydrocarbons in the pyrolytic naphtha. The alphatics in the pyrolytic naphtha were predominantly unsaturated hydrocarbons. It was concluded that the pyrolytic naphtha might be used as a feedstock for BTX-aromatics.
Abstract: The aggregating characteristics variation of asphaltenes of Middle East AR (ME-AR) during thermal reaction was studied. The aggregating characteristics of asphaltenes were demonstrated by the values of critical micelle concentrations (cmc). The cmc values of asphaltenes of ME-AR,40mim and 160min thermal reacted samples were 1.35×10-3mol·L-1,1.29×10-3mol·L-1 and 1.45×10-3mol·L-1. The aggregating tendency of asphaltenes was increasing during coke-induction period as thermal reaction going on, and was decreasing after that. Furthermore, the results of cmc showed that the asphaltene molecules were aggregated during VPO MW measurement. But asphaltenes were single when the solution concentrations were less than cmc. Hence the ratio of VPO MW to that gained by surface data of asphaltene solutions can be defined as aggregating parameter. The aggregating parameter was consistent with that of cmc. This paper manifested that asphaltenes tending to aggregating preferred to aggregating and coking during thermal reaction.
Abstract: Fly ash resulted from municipal solid waste incinerator(MSWI)contains high levels of leachable heavy metals and high TEQ dioxins, and is usually classified as a hazardous waste. Thus further detoxification and stabilization treatment are necessary to MSWI fly ash before disposal. The physical and chemical characteristics of MSWI fly ash have an important influence on treatment. Eight types of MSWI fly ashes were collected from several incinerators in China and France. The composition, melting point, crystal characteristic and pore characteristic of fly ash samples were analyzed in details. The results show that the composition is affected significantly by raw material, type of furnace and the position of sampling et al. The melting point of MSWI fly ash is lower than that of coal-waste, because of different content of SiO2. The main crystalline phase for each fly ash is different. The range of inner aperture of fly ash is mainly in the size 0.3 μm～1.5 μm, and the specific surface area is about 20.5 m2/g.
Abstract: The hydrocracking of Gudao residue in supercritical water using different hydrocracking media (CO+H2/H2O, CO/H2O, H2/H2O, H2) and in situ generated hydrogen from water gas shift reaction(WGSR)in the presence of dispersed catalyst precursor phosphomlybdic acid (PMA) was investigated. The results show that catalytic hydro-con-version of Gudao residue using in situ generated hydrogen is an effective upgrading technology for heavy oil. In situ generated hydrogen from WGSR is more reactive than the supplied molecular hydrogen for residue hydro-conversion. Under the proper reaction conditions, the hydro-conversion of residue in supercritical water-syngas system is similar to hydro-conversion of residue with the supplied molecular hydrogen.
Abstract: The Russian sour crude Atmospheric Residuum (AR) FCC experiments were performed in fixed fluidized bed reactors in order to investigate its catalytic cracking characteristics and the sulfur distribution in products. The results showed that its catalytic cracking characteristics are similar to the normal AR. Reaction temperature had less effect on light oil productivity, while the light oil productivity decreased with increase of catalyst-to-oil ratio. During catalytic cracking, 40% of sulfur content in Russian sour crude AR became smaller sulfur compounds such as H2S, 25% of that distributed in diesel as thiophene and its derivatives, 10% of that distributed in coke, only 4%～6% of sulfur compounds such as sulfide and thiol distributed in gasoline. Sulfide and thiol are easy to be deprived as conversing into lighter sulfur compounds such as H2S. Hence sulfur content in gasoline decreased with increase of reaction temperature and catalyst to oil ratio, while the sulfur content in diesel showed reverse tendency because thiophene and its derivatives hardly decomposed under the cracking conditions. When the yield of light oil reached to 63.38%, sulfur concentration was 1197.82 mg/kg in gasoline and 18700.79 mg/kg in diesel oil at 520 ℃ and catalyst-to-oil ratio of 6. Therefore, it is difficult to get better desulfurization effect through optimizing the cracking conditions. The catalyst with desulfurization activity should be used to make much more sulfur content converse to smaller sulfur compounds such as H2S, and then the cleaner light oil with less sulfur could be produced.
Abstract: The water gas shift reaction over an environmental friendly iron-based shift catalyst NBC-1 was investigated in a fixed-bed plug flow microreactor at 618 K～723 K and 1.0 MPa. The microkinetics were evaluated by a power law kinetic model, which was found to give an excellent representation of the kinetic data. Comparatively, the activation energy of this catalyst is lower than that of the conventional iron-chromium for the water gas shift reaction, which has higher activity at lower temperature. The influence of H2O on the reaction rate is greater comparing with traditional ferrochrome shift catalysts, which may be resulted from the additional Ce component in this catalyst. The presence of CO2 in the reaction system results in the decrease of reaction rate greatly. It is crucial to reduce the resistance effect of the CO2 in favor of the water gas shift reaction rate. The influence of H2 on the reaction rate can be neglected.
Abstract: Binary-structured Al2O3 supports were prepared with sol-gel technique and Ni-Mo/Al2O3 catalysts were prepared by impregnation method with the modified supports. The HDS activity of the catalysts supported by sol-gel modified supports was evaluated in a fixed-bed micro-reactor under moderate-pressures. The results revealed that, the HDS activity of the catalysts on modified support with alumina sol was higher than that of catalysts on ordinary supports. The supports modified and the catalysts prepared were characterized by XRD, TEM and pyridine-IR. The XRD patterns and TEM results indicated that the alumina sol was present in phase of η-Al2O3 on the surface of supports and the η-Al2O3 particles were close to nanometer size. The pyridine-IR results indicated that the acidities (the Brönzed + Lewis) of the catalysts on modified supports are higher than those of the catalysts on ordinary supports. The HDS activities of the catalysts are increased due to the nanometer size of η-Al2O3 and the increase in acidic amounts of the catalysts.
Abstract: Hydrodesulfurization(HDS) of 4-methyldibenzothiophene(4-MDBT) and dibenzothiophene(DBT) on sulfided CoMo/γ-Al2O3 catalyst was studied. Moreover, reaction networks and mechanisms were revealed on the basis of GC and GC-MS analyses of the reaction products. It was found that the HDS of 4-MDBT on sulfided CoMo/γ-Al2O3 catalyst occurs through the direct hydrogenolysis of C-S bond of 4-MDBT and hydrogenation routes, the con-tributions of both routes being comparable. HDS of DBT on the sulfided CoMo/γ-Al2O3 catalyst occurs essentially through the direct hydrogenolysis route. The methyl group in 4-MDBT causes the spatial restraining for the “end up adsorption” of sulfur atom on the active site of the catalyst, which slows down the reaction rate of the direct hydro-genolysis route and leads to the reduction of conversion of 4-MDBT. The reaction rate of the hydrogenation routes in HDS of 4-MDBT and DBT obviously decreases with the descending of reaction pressure. Reaction pressure was also found to have smaller and opposite effects on hydrogenation routes and the direct hydrogenalysis routes in HDS of 4-MDBT and DBT, i.e., the reaction rate of the direct hydrogenalysis routes slightly ascends with the descending of reaction pressure. The effect of reaction pressure on the conversion of 4-MDBT is higher than that on DBT. Reaction temperature has obvious effect on both the direct hydrogenolysis routes and the hydrogenation routes in HDS of 4-MDBT and DBT. Moreover, effect of temperature on the direct hydrogenolysis route in HDS of DBT is lower than the hydrogenation route. However, the effect of temperature on the direct hydrogenolysis route in HDS of 4-MDBT is slightly higher than the hydrogenation route. The electron donor induction of the methyl group in 4-MDBT can promote the hydrogenation of the adjacent benzene ring.
Abstract: In a D300mm jetting fluidized bed with a three-nozzle distributor, the voidage distribution was simulated by two fluid model combined with kinetic theory of granular flow. It was found that the simulating results were in good agreement with the experimental data. Based on the model, the effects of various elevation angles on the voidage distribution in the fluidized bed were discussed. The results showed that the change of nozzle elevation angles would influence the voidage distribution in the fluidized bed.
Abstract: Cu-Mn-Zn/Y catalyst prepared by the co-precipitation impregnation method for the synthesis of DME was investigated. It was found that the molar ratio of Zn to Mn had great effect on the activity and selectivity of the catalyst. The superfluous Mn content restrained the synthesis of DME faintly. The excess content of Zn lowered the conversion of CO greatly. The zeolite Y influenced the activity of dehydrating component and the proportion of Cu-Mn-Zn content in combination of the catalyst. The surplus Y-zeolite reduced the conversion of CO and the selectivity of DME. From this results, when the ratio of n(Zn)/n(Mn) was 1/3～1/2 and the content of Y-zeolites was 33% in the Cu-Mn-Zn/Y catalyst, the CO conversion and the DME selectivity reached 66% and 68%, respectively, at the conditions of 245 ℃. 2.0 MPa, 1500 h-1 and V(H2)/V(CO)=1.5. When the CO conversion and the DME selectivity were taken into all-around account, the best reaction temperature was about 260 ℃.
Abstract: The optimum parameters as well as the ZSM-8 molecular sieve product with good properties were obtained through detailed synthesis investigation under hydrothermal conditions. Composite support, which was formed from an Amorphous Si-Al gel and ZSM-8 zeolite, was impregnated with active components to produce the non-precious metal catalyst for hydrodewaxing. The aim to increase the catalytic isomerization ability was thus realized by additional introduction of zinc and tungsten beside the main molybdenum and nickel. It has been shown that the catalytic properties are significantly influenced by both the catalyst support and the addition of the promoters. However, the addition sequence of zinc shows little effect. Compared to the β-zeolite based catalyst, the new ZSM-8 based catalyst showed a better catalytic behavior, which was characterized by an increased yield and a higher viscosity index of lube base oil product. The improvement of catalyst performance could be ascribed to the increased isomerization ability of new catalyst system.
Abstract: The CuPWTiO2 catalysts were prepared with tetrabutyl titanate hydrolysis by aqueous solutions of Cu salts of the 12-tungstophosphoric acid via sol-gel method. Chemical composition, thermal stability, chemisorption character and reaction behaviours have been studied by different techniques including X-ray diffraction, thermogravimetric analysis, infrared spectrum analysis, inductively coupled plasma atomic emission spectroscopy, temperature-programmed desorption, and microreactor. The experimental results showed that inorganic precursor polyoxotungstate was introduced on the surface of titanium dioxide and formed to the CuPW/TiO2 hybrid materials. Under temperature of 623 K, the catalyst still remains the original Keggin structure of TPA. The experimental results showed also that CO2 chemisorbs at bridging oxygen of Cu—O—W(Lewis base site) and Cu2+(Lewis acid site) to form bridged adsorption states, that propylene chemisorbs on the surface of catalyst to form molecular absorption states, and that the main reaction products of CO2 with propylene on the catalysts are MAA, with propylene conversion of 4.3% under the reaction temperature of 563 K and 1 MPa, MAA selectivity of 96%.
Abstract: The effects of catalyst preparation conditions, reaction temperature, pressure, methanol/tert-olefin molar ratio and space velocity on the titled raction were investigated over P-loaded zeolite β catalysts in a fixed-bed reactor. At optimized reaction condition, the highest conversion of tert-olefin could reach 56.91%. The result showed that P-loaded zeolite β catalysts had good activity, selectivity and stability. The catalyst could be easily regenerated after deactivation.
Abstract: The thermogravimetric analysis was used to study the pyrolysis characteristics of furfural residues. The result showed that furfural residues pyrolysis process had five distinct phases with increasing temperature. TG and DTG analysis and comparison were used to study the pyrolysis of furfural residues at different heating rate (5℃/min, 20℃/min, 50℃/min and 80℃/min) and different particle size distribution in a stream of N2. It showed that the beginning temperature of pyrolysis rose with the heating rate and particle size distribution increasing. Based on the experimental data, a pyrolysis kinetics model was proposed and the related kinetics parameters of furfural residues pyrolysis were determined. The results indicated that the pyrolysis process can be described by three-order model. These conclusions provided a theoretical foundation for further research on combustion and gasification of furfural residues.
Abstract: CuO/γ-Al2O3 and CeO2-CuO/γ-Al2O3 catalysts were prepared by impregnation. The effect of calcination temperature on C3H6-SCR of NO over CuO/γ-Al2O3 and CeO2-CuO/γ-Al2O3 catalysts CeO2 with different loadings was investigated. The results showed that calcination temperature had little effect on the activity of C3H6-SCR of NO over CuO/γ-Al2O3 when calcinated from 200 ℃ to 500 ℃. NO conversion sharply decreased when increasing the calcination temperature from 500 ℃ to 800 ℃. It could be caused by the formation of CuAl2O4, which was confirmed in XRD patterns. The activity of C3H6-SCR of NO over CuO/γ-Al2O3 catalyst could not be promoted by the addition of CeO2 calcinated at 500 ℃, while could be improved calcinated at 800 ℃. The highest NO conversion was achieved while the mole ratio of Ce to Cu was 1∶10.
Abstract: Ultrafine particles (10 nm～30 nm) of TiO2 doped with Co were prepared by titanic chloride hydrolysis. Cobaltous nitrate was used as dopant. The properties of the samples were characterized by means of XRD (X-ray dif-fraction), TEM (transmission electron microscopy) and FT-IR (Fourier transform infrared spectroscopy) techniques, and the evaluations of photocatalytic activity in gas-phase were performed, as well. It was found that after doping with Co, the temperature of transition from anatase to rutile was reduced obviously. When the dopant amounted to 4%, the phase-transition temperature dropped about 90 ℃. The effects of pH on the phase transition were also observed. The smaller the pH value was, the lower the phase-transition temperature was. The sample calcined at 500 ℃ consisted of basically rutile at pH<3. It is proved by IR analysis that the sample doped with Co has very good hygroscopicity. The effects of doping Co on catalytic activity were studied by photocatalytic reaction of benzene in a fixed-bed photoreactor. It is showed that doping Co enhanced the catalyst activity and especially was favorable to the decomposition of benzene, which is hard to decompose. Under the experimental conditions, benzene led to deactivation of the pure TiO2 after 160 min time-on-stream, but activity of Co doped catalyst is still 50%.
Abstract: The techniques such as NH3-TPD, FT-IR, XRD were used to investigate the acid properties and hydrothermal stability of zeolite Y modified with rare earth and phosphorus (P-RE-USY), and the catalyst using P-RE-USY as an active component was evaluated in a small confined fluidized bed apparatus. The results have shown that P-RE-USY has good hydrothermal stability owing to the migration of hydroxy rare earth cation from the super cages to the sodalite cages enhanced by phosphorus addition, inhibiting the framework dealumination of zeolite in the steaming condition. The acid distribution of P-RE-USY is more concentrated in the range of intermediate and strong acidity, improving the hydrogen transfer activity. The reduction of strong acid decreases the formation of coke. The catalyst containing P-RE-USY exhibits excellent performance of reducing naphtha olefins, increasing diesel yield more than 2.31%.
Abstract: The alkylation of methylnaphthalene and methanol was carried out on HZSM-5 zeolite catalyst. The characteristics of coke deposited on the catalysts under the atmospheric pressure or supercritical fluid condition were found out and coke-burning reaction apparent activation energies of the used catalysts were calculated by using the thermo gravimetric analysis technique. The results showed that compared to the catalyst used at the atmospheric pressure, coke deposition was greatly depressed and life of catalysts increased 10 times under the supercritical fluid reaction condition. The coke-burning reaction of the used catalysts mainly happened at temperature range of 420 ℃ to 580 ℃. The longer reaction time led to higher peak temperature of weight loss and to greater coke-burning reaction apparent activationenergies of the used catalysts.
Abstract: The effects of dispersed catalyst and hydrogen donor on the cracking and cracking selectivity of characteristic model compounds in residue oil, such as N-eicosane, butyl benzene and 1,6-diphenylheptane, were investigated in the thermal, hydrothermal and catalytic hydrocracking systems at 440 ℃. The three compounds had different cracking characteristics. N-eicosane had the simplest bond-scission way. The bond-scissions of butyl benzene in the thermal system were mainly β- and γ- bond-scission, while β- in hydrothermal and α- bond-scission in catalytic hydrocracking were main reactions. 1,6-diphenylheptane had more complex cracking ways, which were α-, β-, homolysis and γ-bond-scission. The bond-scissions of 1,6-diphenylheptane in thermal cracking underwent such four ways, how-ever, α- and β-bond-scission or α-bond-scission were main reactions in hydrothermal or in catalytic hydrocracking of 1,6-diphenylheptane, respectively. It seems that these three model compounds experienced the radical reaction in the single systems of model compounds or in the binary system of model compounds/tetralin for thermal, hydrothermal and catalytic hydrocracking. Molecular hydrogen as well as dispersed catalyst enhanced the cracking of model compounds, while H-donor depressed the cracking. For cracking selectivity of the three compounds, thermal and hydrothermal cracking were the basis of other processes and dispersed catalysts clearly affected the cracking selectivity of alkyl aromatics. On the other hand, hydrogen donor had influence on a certain extent on the cracking selectivity on the basis of the thermal, hydrothermal and catalytic hydrocracking systems.
Supervisor：Chinese Academy of Sciences
Sponsors by：Shanxi Institute of Coal Chemistry, Chinese Academy of Sciences Chinese Chemical Society
