Abstract: Different mesoporous activated carbons were prepared by both chemical and physical activation processes and were examined for methane uptake in the presence of water. Methane isotherms were obtained at wet condition by wetting samples with water at mass ratio of water/carbon (R) close to 1.0. To compare, the amount of methane storage were also measured at dry situation. The maximum amount of methane stored was attained as 237 V/V at R=1.0 by hydrate formation at the methane critical pressure. In the next step, mass ratios of water/carbon were changed to investigate various amount of water for methane storage enhancement. Two other values of mass ratio of water/carbon (R=0.8 and 1.4) were selected and methane isotherms were obtained at the same conditions. Maximum values of 210 and 248 V/V were reached for methane storage, respectively. It was also observed that, in the pressure range lower than hydrate pressure, by increasing water ratio the hydrate formation pressure was decreased and methane uptake was much less than that of dry condition due to pore filling by water.
Abstract: Four biomass of rice straw (RS), rice husk (RH), wood chips (WC) and cotton straw (CS) were chosen to prepare biomass chars which characterized by nitrogen adsorption/desorption and Fourier transform infrared spectroscopy (FT-IR). The influence of biomass type and pyrolysis temperature on pore structure and surface chemical properties of the chars was investigated. Mercury adsorption experiments were carried out in a fixed-bed reactor. The results show that specific surface area, micro-pore volume and fractal dimension of the biomass chars increase firstly and then decrease with increase of the pyrolysis temperature. With the pyrolysis temperature increasing, both the quantity and sorts of the superficial functional groups on the biomass chars reduce and they are dependent greatly on the biomass sorts. Both the superficial functional groups and contents of RH600 and RS600 are more abundant than that of WC600 and CS600. It is not simply direct relationship among the mercury adsorption capacity, the micro-pore volume and the fractal dimension of the biomass chars. It is supposed that the oxygen contained functional group may have dominant effect on the mercury adsorption.
Abstract: Ten major trees that can be used as the potential raw materials of biodiesel are taken as the research objects, and the influence of their fruit or seeds’ fatty acid composition on the biodiesel was studied. The results showed that the fuel properties such as cetane number, idodine number and oxidation stability were mainly determined by the degree of unsaturation of raw oils fatty acid. When the degree of unsaturation of raw oils fatty acid was lower than 133.13, cetane number (GB/T 20828-2007) and iodine number (EN 14214) could be up to the standards. With the increase of the long chain saturated fatty acids, cold filter plugging point of the biodiesel product tended to be higher. When the chain length saturated factors less than 8.41 and 2.72, it could meet the standards of 0℃ and -10℃ of cold filter plugging point. The raw materials for high-quality biodiesel should have high content of monounsaturated fatty acids. Basis on the study of the compositions of monounsaturated, polyunsaturated and saturated methyl esters, a triangular prediction graph for biodiesel fuel properties was worked out, which could provide references for the prediction of the fuel properties of biodiesel product.
Abstract: Fe-Ca bifunctional magnetic solid base (CaO·γ-Fe2O3) was prepared via in-situ coprecipitation and used as catalyst in transesterification of rapeseed oil to produce biodiesel. The catalyst was characterized by XRD, BET, TG-DTA, SEM and VSM and the amounts of Ca and Fe leached in fatty acid methyl ester were measured through ICP-AES. The results indicated that Ca and Fe components are well composited; the CaO·γ-Fe2O3 catalyst exhibits good magnetic properties with high saturation magnetization (45.7emu/g), much higher than that of those magnetic base catalysts reported up to now. Under the mild conditions of 64℃, catalyst amount of 2.5%, methanol/oil mol ratio of 15, and reaction time of 2h, the oil conversions for first three cycles remain above 95%.
Abstract: The rare earth-promoted SO42-/ZrO2 solid super acid catalyst was prepared by the co-precipitation and impregnation method under different conditions. The catalytic properties of the samples were evaluated through transesterification of waste oil and methanol and characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and BET surface area measurement. The results showed that among all the prepared samples the one that was calcined at 600℃ with La doping 4% had the highest production rate of 64.68%. An analysis of XRD patterns revealed that the incorporation of rare earth into tetragonal zirconia stabilizes the compound, and the calcination at 600℃ increases the reactivity of the catalyst by producing a greater fraction of active tetragonal zirconia with a larger surface area. It could be seen from the FT-IR spectra that super acid structures were formed in the catalysts and the acidity was strengthened remarkably and the activated centre of the catalyst were increased.
Abstract: Porous Ce0.5Zr0.5O2 solid solution support was first prepared by a co-precipitation method. Then, different concentrations of Co (10%, 20%, and 30 %) were loaded over Ce0.5Zr0.5O2 by impregnation process. The fresh catalysts were characterized by some physicochemical characterizations such as N2 physical adsorption(BET), X-ray diffraction (XRD), temperature-programmed reduction of hydrogen (H2-TPR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The amount of deposited carbon over used catalysts was analyzed by temperature-programmed oxidation of oxygen (O2-TPO) and thermogravimetry (TG). The catalytic performance of these Co/Ce0.5Zr0.5O2 catalysts was evaluated by methane partial oxidation to produce synthesis gas. The results show that cobalt oxide is easy to be reduced to metal cobalt over Ce0.5Zr0.5O2. This series of Co/Ce0.5Zr0.5O2 catalysts show high activity and selectivity to H2 and CO. It was found that loading high concentration of Co could benefit the increase in catalytic activity and ability to resist the coke.
Abstract: Fluorine-modified Ni-Mg-Al mixed oxides (Ni/Mg/Al/O-F) prepared from thermal decomposition of hydrotalcite-type (HT) precursor was characterized by XRD, SEM, CO2-TPD, H2-TPR, and N2 sorption and used as catalyst in partial oxidation of methane (POM) to syngas. The results indicated that Ni/Mg/Al/O-F catalyst after calcination takes the mesoporous structure of periclase. Compared with the non-modified Ni-Mg-Al mixed oxides (Ni/Mg/Al/O), Ni/Mg/Al/O-F exhibits lower surface area, lower crystallinity and smaller particle size, but higher basicity of moderate and strong intensity. Ni/Mg/Al/O-F exhibits high activity and stability in POM; the activity at 1053K retains without deactivation even after 120h on stream. The presence of the F-anions can enhance the dispersion of active nickel species and their resistance to coking, which may contribute to the high performance of Ni/Mg/Al/O-F catalyst.
Abstract: Ni-based catalysts for methanation were prepared by three different precipitants:urea, ammonium carbonate,ammonia and their activities were investigated under different conditions.The characterization of the catalysts were determined by XRD,H2-TPR,BET and TPO.Based on the results,the catalysts prepared by different methods of precipitation exhibited different catalytic properties:the surface area of the catalyst prepared by using urea reached up to 223.55m2/g,which suggested an stabilized catalytic activity;the catalyst prepared by ammonium carbonate precipitant had larger size particles,non-uniform distribution and more carbon deposition;the catalyst prepared by ammonia precipitant possessed smaller particle size,stronger interaction with support,but the loss of active components was more serious especially at high temperature.It was indicated that the precipitants mainly affected the shape and inner structure of the catalyst precursors,resulting in different fields of dispersion,crystal structure and hydrogen adsorption capacity.Thus,the activities and stabilities of the catalysts were different.
Abstract: CuCo-based catalysts for the synthesis of higher alcohols from syngas were prepared by the ultrasound assisted reverse coprecipitation. The effects of rare earth La promoter on the structure and catalytic performance were investigated. The catalysts were systematically characterized by means of X-ray diffraction (XRD), N2 adsorption isotherm (BET) and temperature-programmed desorption (CO-TPD) techniques. The catalytic performance for CO hydrogenation to higher alcohols was also evaluated. The experimental results showed that with the addition of La, the crystal size of the sample was decreased, the specific surface area was increased notably, the formation of the active sites for alcohol formation was improved and the concentration of more strongly adsorbed CO-species was increased. Therefore, the catalytic activity and higher selectivity to C2+ alcohols were improved obviously, and the content of methanol in mixed alcohols was reduced significantly.
Abstract: Co-based catalyst supported on bi-modal MCM-41 molecular sieves was prepared by incipient-wetness impregnation method; the influence of reduction and oxidation pretreatment on the catalyst structure and its performance in Fischer-Tropsch synthesis (FTS) was investigated. XRD results showed that the cobalt species in the catalyst after the pretreatment is in the form of metal cobalt with face centered cubic crystal phase and the crystallite size is increased from 8.4nm to 22.6nm, compared with the untreated one; due to the increase of crystallite size, the Raman characteristic peak shows a blue shift. SEM and TEM results indicated that the cobalt species exhibits good dispersibility. H2-TPR results indicated that the reduction temperature is reduced and the interaction between metal and support is strengthened after the pretreatment. As a result, the pretreated-catalyst exhibits lower FTS activity and higher selectivity to methane than the fresh catalyst; however, the selectivity to C5~18 products over the pretreated-catalyst is improved obviously, especially, the selectivity to C5~11, which is about twice as that over the untreated one.
Abstract: This article reports the study on the effects of CS2 exposure on the Cu-Zn-Al slurry catalysts prepared by a complete liquid phase technology and characterized by X-ray diffraction(XRD), H2-TPR,and NH3-TPD. For the Cu-Zn-Al catalyst prepared by complete liquid-phase technology, low-level sulfur addition(<4mg/L)did not significantly influence the conversion of CO. But the addition of a higher-level loading of sulfur(>100mg/L)resulted in severe sulfur poisoning of the catalysts.
Abstract: Polyphenylene sulfide (PPS) filter was treated by nitric acid to form PPSN filter. By the ultrasonic method, PPSN filter was loaded on 40% manganese molar fraction of MnOx-CeO2 which was calcined at 400℃ to form MnOx-CeO2/PPSN. The activity of MnOx-CeO2/PPSN was tested in the presence of NH3 as reducing agent for selective catalytic reduction of NO. The influences of catalyst temperature, volume fraction of NH3 and O2, and catalyst loadings on the de-NO efficiency were studied too. It was found that MnOx-CeO2/PPSN filter with the catalyst loadings of 296g/m2 showed higher de-NO efficiency under the conditions of temperature 130~160℃, NH3/NO>1, and O2 5%. When the catalyst temperature, the volume fraction of NH3 and O2 are constant, de-NO efficiency of MnOx-CeO2/PPSN is higher with the catalyst loading increasing.
Abstract: The V2O5-Sb2O3-TiO2 catalyst was prepared by impregnation method. The influences of V2O5and Sb2O3 loading, pH value, and calcination temperature on the low temperature selective catalytic reduction (SCR) activities of NO with ammonia over V2O5-Sb2O3-TiO2 catalyst were studied. The performance of V2O5-Sb-TiO2 catalyst in resisting the H2O and SO2 poisoning was also discussed. The results show that the catalyst has the best SCR activity. When the V2O5 and Sb2O3 loading is 5% and 2%, respectively, the calcination temperature is 400℃, and the pH value is 4. The NO removal efficiency of 97% is obtained at the reaction temperature of 220℃. The addition of Sb2O3 not only strengthens the catalytic activity of V2O5-TiO2, but also improves the resistance to the deactivation by both H2O and SO2. The SO2 and NO adsorption transient response and TG-DTG test demonstrate that the promoting mechanism of Sb2O3is mainly to promote the catalyst adsorption of NO, and weaken the interaction between ammonium sulfate and the catalyst, which can result in the decomposition of ammonium sulfate easier.
Abstract: Urea as reducing agent supported on pitch-based spherical activated carbon (PSAC) was studied for NO2 reduction at low temperatures (30~90℃). The results showed that increasing urea loading from 8% to 30% raised the reaction probabilities of selective catalytic reduction (SCR) of NO2 by urea, which resulted in significant increase of the SCR activity; moreover, the NOx removal period was extended. In the temperature range of 30~90℃, high reaction temperature was unfavorable for NOx removal on account of the decreased NO2 adsorption on PSAC.It was found that the SCR activity was improved by increasing NO2 or O2 concentration in the feed gas. However, further increase in O2 concentration above 9% made a weak contribution to the improvement of the SCR activity. Decreasing space velocity not only increased the SCR activity but also prolonged the NOx removal period. More than 85% NOx conversion for 49 h could be achieved over PSAC with 8% urea loading at 30℃ under the condition of 0.05% NO2, 21% O2 and a space velocity of 2000h-1.
Abstract: In this paper, a series of TiO2 supported vanadium pentoxide and copper oxide catalysts were prepared by the impregnation method for selective catalytic reduction of NOx with NH3 at middle-low temperature (200~300℃). The catalysts were characterized by BET and X-ray diffraction (XRD). The results showed that 2V16Cu/TiO2 calcinated at 500℃ exhibited the best catalytic activity at middle-low temperature and quite wide temperature window. A 97.3% NOx conversion was obtained at 225℃ and a gross hourly space velocity (GHSV) of 6.0×104h-1, and it reached 100% at 250~300℃. XRD results showed that the characteristic peak of CuO gradually emerged with the increase of CuO loading. CuO was the key active component of the VCu/TiO2 catalysts, and affected the catalytic activity at middle-low temperature significantly. The BET results showed that the CuO loading had great influence on surface structure of vanadium-titanium catalyst. The test of sulfur resistance performance showed that 2V16Cu/TiO2 which was prepared by the introduction of vanadium pentoxide improved its sulfur resistance performance slightly.
Abstract: Cu/ZSM-5 catalysts were modified by adding Ce and Zr components and then characterized by O2-TPD and TG analysis. The effect of ion-exchange sequence, Ce/Zr mol ratio and reaction conditions on the catalytic performance of Ce and Zr modified Cu/ZSM-5 were investigated. The results indicated that Cu species is essential in Zr-Cu-Ce/ZSM-5 catalyst as the active sites for NO decomposition, while the modification with Ce and Zr components can significantly enhance its catalytic performance for direct decomposition of NO in the presence of oxygen and reduce the reaction temperature required for achieving the maximum conversion of NO. The Zr-Cu-Ce/ZSM-5 catalyst modified by simultaneous Ce and Zr ion-exchange with Ce/Zr mol ratio of 1 exhibits thehighest performance for NO decomposition.
Abstract: The catalytic performance of Pd/Al2O3-TiO2, V/Al2O3-TiO2 and V-Pd/Al2O3-TiO2 with different vanadium contents prepared by impregnation method for the complete oxidation of ethanol and acetaldehyde has been investigated. The result indicated that the appropriate amount of vanadium oxide (1%~3%) can modify the characters of Pd/Al2O3-TiO2 catalyst distinctly, and improve the catalytic activity of complete oxidation of ethanol and acetaldehyde. The relationship between surface characters of catalyst and the activity was studied by means of XRD, NH3-TPD, N2 adsorption. The results indicated that Pd/Al2O3-TiO2 catalyst added with proper vanadium content which showed the best catalytic performance result in the proper superficial acidity, the proper surface area and pores of the catalyst, and that has revealed a strong interactions among V, Pd and the carrier.
Abstract: The effects of W content on the performance of the Pd-SO42-/ZrO2-WO3 solid super acid catalyst was studied using n-pentane isomerization as a probe reaction and the catalysts were characterized by X-ray diffraction(XRD), FT-IR, H2-TPR, specific surface area measurements(BET), thermogravimetry-differential thermal analysis(TG-DTA) and NH3 temperature-programmed desorption(NH3-TPD). The effects of WO3 content on the acidity, surface area and crystal structure of catalyst were researched. The catalytic activity of the Pd-SO42-/ZrO2-WO3 solid super acid catalyst with a mass fraction of 13% WO3 which was calcinated at 600℃ was found to be the best. At reaction temperature of 260℃,space velocity of 1.0h-1,H2/ n-pentane mol ration of 4.0 and reaction pressure of 2.0MPa, the iso-pentane yield was 40.1%. The iso-pentane yield was stabilized in about 38% and the selectivity is higher than 95.3％within 80h .
Abstract: Heat treatment at high temperature was used to modify HZSM-5 zeolites. The HZSM-5 samples before and after heat treatments were characterized by X-ray diffraction (XRD), 27Al-MAS NMR, N2 adsorption, inductively couple plasma emission spectroscopy (ICP-AES), temperature-programmed desorption of ammonia (NH3-TPD), and Fourier transform infrared (FT-IR) spectroscopy of adsorbed pyridine. The effects of heat treatment conditions on the structure, acidity, and catalytic performance of HZSM-5 zeolites in dehydration of ethanol to ethylene were investigated. The results showed that the heat treatment leads to dealuminization from the zeolite framework and channels, which may decrease the amount of Bronsted acid sites, increase the Lewis acid sites and the pore volume, and form new mesopores. When the heat-treated HZSM-5 is used as the catalyst in ethanol dehydration, owing to its appropriate acidity and binary meso/micro porous structure, the side reaction is reduced and the selectivity to ethylene and the catalyst life time are increased significantly.
Abstract: As a support, AlMCM-41 containing aluminophosphate building units with different Si/Al molar ratio(Si/Al=30, 40, 50, 55, 60, respectively) was synthesized by microwave heating method. The supported tungsten phosphide(WP) catalysts with different Si/Al molar ratio were prepared by impregnation and H2-TPR(temperature programed reduction in hydrogen flow)method. The samples were characterized by X-ray diffraction (XRD), BET specific surface area, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) methods. The dibenzothiophene (DBT) hydrodesulfurization (HDS) activities of the catalysts were evaluated by a fixed-bed micro-reactor. Active species of WP and the structure of -Al-O-W-P, the matter with some activity, were detected on the catalysts surface. WP was the dominative active phase. The percentage of active phase WP on the catalyst surface was influenced by the Si/Al molar ratio. Catalysts with different Si/Al molar ratio exhibited different selective hydrogenation performances, and direct hydrodesulfurization(DDS) was the main DTB HDS route. Catalyst with Si/Al molar ratio of 55 was found to give a higher DDS products (PB) selectivity of 82.7% and a higher DBT HDS conversion of 93.1%, which was favor to reducing the hydrogen consumption and protecting the environment.
Abstract: A heteroatom Y zeolite (AlY) was prepared by introducing gallium atoms into the framework of Y zeolite through a secondary synthesis method (isomorphous substitution), i.e. treating Y zeolite with an aqueous solution of ammonium hexafluoro gallate. The performance of AlY in adsorptive desulfurization was investigated with various model fuels containing about 500?10-6 sulfur. The results indicated that the sulfur adsorption capacities of AlY towards thiophene, tetrahydrothiophene (THT), 4,6-dimethyldibenzothiophene (4,6-DMDBT), dibenzophiophene (DBT), benzothiophene (BT) and 4-methyldibenzothiophene (4-MDBT) are 7.0, 17.4, 14.5, 16.9, 6.9 and 5.8 mg-S/g-adsorbent, respectively. A density functional theory (DFT) calculation shows that the charges on S atom in thiophene, THT, 4,6-DMDBT, DBT, BT and 4-MDBT molecules are -0.159, -0.298, -0.214, -0.211, -0.193 and -0.188, respectively, implying that the S-M bond between the adsorption sites and thiophene molecules is much weaker than that between the adsorption sites and the molecules of THT, 4,6-DMDBT or DBT. Moreover, the sulfur removal rate of FCC gasoline on AlY is 68%.
Supervisor：Chinese Academy of Sciences
Sponsors by：Shanxi Institute of Coal Chemistry, Chinese Academy of Sciences Chinese Chemical Society
