过刊目录

2012, Vol. 21, No. 1　Online: 2012-01-12

上一期    下一期

全全选选:

导出引用 EndNote Ris BibTeX

隐藏/显示图片

Articles

Select

Effect of alcohol solvents treated ZrO(OH)2 hydrogel on properties of ZrO2 and its catalytic performance in isosynthesis Rongjun Zhang, Dehua He* 2012, 21(1): 1-6.  DOI: 10.1016/S1003-9953(11)60324-1 摘要 ( 10273 )   A series of ZrO2 catalysts with different physicochemical properties were prepared by treating ZrO(OH)2 hydrogel with different alcohol solvents (C2--C4 alcohols) and calcining under N2 flow at 773 K for 3 h. The obtained ZrO2 catalysts were systematically characterized by the methods of N2 adsorption-desorption, powder X-ray diffraction, NH3 temperature-programmed desorption, and CO2 temperature-programmed desorption. The catalytic performance of each catalyst was evaluated in the selective synthesis ofiso-C4 (isobutene and isobutane) and light olefins (C=2~C=4) from CO hydrogenation. The specific surface area increased for the ZrO2 catalysts obtained by treating ZrO(OH)2 hydrogel with different alcohol solvents. The amounts of both acidic and basic sites on the catalyst surface increased obviously. The catalytic activity (CO conversion) of ZrO2 catalysts also increased after the treatment with different alcohol solvents. The highest activity was obtained over the catalyst which was pretreated with isopropanol. However, alcohol solvent treatment retarded the transformation of ZrO2 crystal structure from tetragonal phase to monoclinic phase, and subsequently resulted in the decrease of monoclinic phase in ZrO2, which led to the decrease of olefin selectivity in corresponding hydrocarbon products (C=2~C=4/CH).

Select

Removal of high concentration CO2 from natural gas at elevated pressure via absorption process in packed column L. S. Tan, K. K. Lau, M. A. Bustam, A. M. Shariff* 2012, 21(1): 7-10.  DOI: 10.1016/S1003-9953(11)60325-3 摘要 ( 10139 )   Carbon dioxide (CO2) removal is an essential step in natural gas (NG) processing to provide high quality gas stream products and minimize operational difficulties. This preliminary study aims to investigate the removal of CO2 at high concentration level from the mixture of CO2-NG gas stream at elevated pressure via absorption process. This is to explore the possibility of exploring high CO2 content natural gas reserves by treatment at offshore platform. A mixed amine solvent, Stonvent-II, was used for the absorption of approximately 75 vol% CO2 in CO2-NG stream at a pressure of 10 barg. The initial solvent temperature was varied in order to study the impact of initial temperature on the absorption performance. Preliminary study at temperatures of 35 ℃ and 45 ℃ indicates that Stonvent-II was able to perform almost 100% removal of CO2 under both conditions. However, the CO2 absorption effect took place faster when the initial liquid temperature was lower. This is because when the initial liquid temperature is high, the reaction heat causes the temperature increase in packing high which impacts the efficiency of absorption negatively.

Select

Preparation of porousα-Fe2O3-supported Pt and its sensing performance to volatile organic compounds Yuhong Cheng, Yanfei Kang, Liwei Wang, Yao Wang, Shurong Wang*, Yujin Li 2012, 21(1): 11-16.  DOI: 10.1016/S1003-9953(11)60326-5 摘要 ( 9697 )   Porous α-Fe2O3 was synthesized by a simple hydrothermal treatment of FeCl3 aqueous solution followed by a calcination process. In the synthesis of porous α-Fe2O3, no templates or pore-directing agents were used. The as-prepared porous α-Fe2O3 was further employed as a support for loading Pt nanoparticles. The gas sensing performance of the obtained porous α-Fe2O3-supported Pt to VOCs was investigated. The sensor presented a high response and fast response-recovery characteristic to several VOCs including acetone, ether, methanol, ethanol, butanol and hexanol. Meanwhile, it exhibited a much higher response than the pure α-Fe2O3 at the operating temperature of 260 ℃. The enhanced sensing properties may be related to the unique porous structure of the α-Fe2O3 support and the promoting effect of active Pt nanoparticles for the sensing reactions.

Select

Selective catalytic oxidation of NO with O2 over Ce-doped MnOx/TiO2 catalysts Xiaohai Li, Shule Zhang, Yong Jia, Xiaoxiao Liu, Qin Zhong* 2012, 21(1): 17-24.  DOI: 10.1016/S1003-9953(11)60327-7 摘要 ( 9958 )   A series of Ce-doped MnOx/TiO2 catalysts were prepared by impregnation method and used for catalytic oxidation of NO in the presence of excess O2. The sample with the Ce doping concentration of Ce/Mn=1/3 and calcined at 300 ℃ shows a superior activity for NO oxidation to NO2. On Ce(1)Mn(3)Ti catalyst, 58% NO conversion was obtained at 200 ℃ and 85% NO conversion at 250 ℃ with a GHSV of 41000 h-1, which was much higher than that over MnOx/TiO2 catalyst (48% at 250 ℃). Characterization results implied that the higher activity of Ce(1)Mn(3)Ti could be attributed to the enrichment of well-dispersed MnOx on the surface and the abundance of Mn3+ and Ti3+ species. The addition of Ce into MnOx/TiO2 could improve oxygen storage capacity of the catalyst and facilitate the oxygen mobility over catalyst shown by PL and ESR, which could enhance the activity of NO oxidation. The effect of H2O and SO2 on the catalyst activity was also investigated.

Select

Synthesis of glycerin triacetate over molding zirconia-loaded sulfuric acid catalyst Lian Wang, Qun Liu, Minghao Zhou, Guomin Xiao* 2012, 21(1): 25-28.  DOI: 10.1016/S1003-9953(11)60328-9 摘要 ( 9947 )   School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, Jiangsu, China 文摘: Zirconia-loaded sulfuric acid catalysts (SO2-4/ZrO2) were prepared by impregnation method, molded by punch tablet machine and characterized by X-ray diffraction. SO2-4/ZrO2 catalyst was used to obtain glycerol triacetate (GTA) directly from glycerin. The effect factors on the reusable times of catalysts and the yield of GTA, such as different temperatures of calcination and catalysts molded or not were investigated. The optimum reaction conditions were shown as follows: the reaction temperature was 403 K; the reaction time continued for 8 h; the amount of molded catalysts was 5 wt% of glycerin and the molar ratio of glycerin to acetic acid was 1 : 8. The yield of GTA was 97.93% under the optimum condition.

Select

Negative effect of Ni on PtHY in n-pentane isomerization evidenced by IR and ESR studies Muhammad Arif Ab Aziz, Nur Hidayatul Nazirah Kamarudin, Herma Dina Setiabudi 2012, 21(1): 29-36.  DOI: 10.1016/S1003-9953(11)60329-0 摘要 ( 10417 )   Ni/PtHY with different Ni loadings was prepared by impregnating HY with hexachloroplatinic acid solution and Ni2+/N, N-dimethylformamide solution. An increase in the Ni loading decreased the crystallinity, specific surface area and meso-micropores of the catalysts. Ni interacted with hydroxyl groups to produce IR absorption bands at 3740-3500 cm-1. Increasing Ni loadings resulted in a decrease in the intensities of the broad bands at 3730-3500 cm-1 and the sharp band at 3740 cm-1 with simultaneous development of new absorbance band at 3700 cm-1 that was attributed to (--OH)Ni. The acidity of the samples did not significantly change with Ni loadings up to 1.0 wt%, which indicated that Ni mostly interacts with non-acidic silanol groups (terminal- and structural-defect OH groups). The presence of Ni decreased the activity of PtHY toward the isomerization of n-pentane because of a decrease in the number of active protonic-acid sites that formed from molecular hydrogen. IR and ESR studies confirmed that Pt facilitated the formation of protonic-acid sites from molecular hydrogen, whereas Ni, even when combined with Pt, didn't exhibit such ability. The absence of protonic-acid sites from molecular hydrogen significantly decreased the yield of iso-pentane and markedly increased the cracking products.

Select

Thermal decomposition and cobalt species transformation of carbon nanotubes supported cobalt catalyst for Fischer-Tropsch synthesis Jing Lü, Chengdu Huang, Suli Bai, Yunhui Jiang, Zhenhua Li* 2012, 21(1): 37-42.  DOI: 10.1016/S1003-9953(11)60330-7 摘要 ( 13376 )   The effect of calcination condition on the cobalt species and Fischer-Tropsch synthesis (FTS) was studied. It was found that higher calcination temperature resulted in decreased FTS activities because CNTs were consumed by oxidation in air at temperature higher than 230 ℃. Cobalt species went through transformation from Co3O4 to metallic Co in Ar by autoreduction at temperature over 500 ℃. The autoreduction route might be Co3O4→CoO→Co or Co3O4→Co2C→Co. Reduction at temperature higher than 500 ℃ also resulted in decreased FTS activities as a result of CNTs methanation in hydrogen.

Select

Oxidative dehydrogenation of propane over Ni-Mo-Mg-O catalysts Lin Wang, Wei Chu, Chengfa Jiang*, Yuefeng Liu, Jie Wen, Zaiku Xie 2012, 21(1): 43-48.  DOI: 10.1016/S1003-9953(11)60331-9 摘要 ( 11531 )   In this work, a series of Ni-Mo-Mg-O catalysts with mesoporous structure prepared by sol-gel method were investigated for the oxidative dehydrogenation of propane (ODHP). The techniques of temperature-programmed reduction with H2 (H2-TPR), N2 adsorption-desorption, Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and X-ray photoelectron spectra (XPS) were employed for catalyst characterization. It is found that the activity of the catalysts for ODHP increases first and then decreases with the increase of Mo content. The catalyst with a Mo/Ni atomic ratio of 1/1 exhibits the best catalytic activity, which gives the propene selectivity of 81.4% at a propane conversion of 11.3% under 600 ℃ and maintains the good catalytic performance for 22 h on stream. This is related not only to its high reducibility and dispersion as revealed by TPR and XRD, but also to the formation of more selective oxygen species on the MoOx-NiO interface as identified by XPS.

Select

Oxidative coupling of methane over BaCl2-TiO2-SnO2 catalyst Zhonglai Wang, Guojun Zou, Xu Luo, Hua Liu, Runxiong Gao, Lingjun Chou*, Xiaola 2012, 21(1): 49-55.  DOI: 10.1016/S1003-9953(11)60332-0 摘要 ( 13881 )   The performance of BaCl2-TiO2-SnO2 composite catalysts in oxidative coupling of methane reaction has been investigated. A series of BaCl2-TiO2, BaCl2-SnO2, TiO2-SnO2, and BaCl2-TiO2-SnO2 catalysts were prepared, and characterized by BET, XRD, XPS, CO2-TPD and H2-TPR, respectively. The synergistic effect among BaCl2, SnO2 and TiO2 compositions enhances the catalytic performance. The best C2 selectivity and ethylene yield are obtained on the catalyst with the equal molar amount of the three compositions (BaCl2 : TiO2 : SnO2 molar ratio of 1 : 1 : 1). The optimal reaction condition is as follows: 800 ℃, 44 mL·min-1 for methane, 22 mL·min-1 for oxygen and a space velocity of 5000 mL·h-1·g-1. And the C2H4 yield over the catalyst is 20.1% with the CH4 conversion of 43.8% and C2 selectivity of 53.3%.

Select

Impact of impregnation pressure on desulfurization performance of Zn-based sorbents supported on semi-coke Xianrong Zheng, Weiren Bao, Qingmai Jin, Ruiyuan He, Liping Chang*, Kechang Xie 2012, 21(1): 56-60.  DOI: 10.1016/S1003-9953(11)60333-2 摘要 ( 9421 )   High-pressure impregnation, a new preparation method for sorbents to remove H2S from hot coal gas, is introduced in this paper. Semi-coke (SC) and ZnO is selected as the support and active component of sorbent, respectively. The sorbent preparation process includes high-pressure impregnation, filtration, ovendry and calcination. The aim of this research is to primarily study the effects of the impregnation pressure on physical properties and desulfurization ability of the sorbent. The desulfurization experiment was carried out in a fixed-bed reactor at 500 ℃ and the simulated coal gas was composed of CO (33 vol%), H2 (39 vol%), H2S (300 ppm in volume), and N2 (balance). Experimental results show that the pore structure of the SC support can be improved effectively and ZnO active component can be uniformly dispersed on the support, with the small particle size of 10--500 nm. Sorbents prepared using high-pressure impregnation have better desulfurization capacity and their active components have higher utilization rate. P20-ZnSC sorbent, obtained by high-pressure impregnation at 20 atm, has the best desulfurization ability with a sulfur capacity of 7.54 g S/100g sorbent and a breakthrough time of 44 h. Its desulfurization precision and efficiency of removing H2S from the middle temperature gases can reach <1 ppm and >99.7%, respectively, before sorbent breakthrough.

Select

Comparison of purification processes of natural gas obtained from three different regions in the world Tansel Koyun, Mehmet Kunduz, Hakan F. Oztop*, Ibrahim Ucgul 2012, 21(1): 61-68.  DOI: 10.1016/S1003-9953(11)60334-4 摘要 ( 9841 )    Natural gases obtained from different regions in the world as Scholen-Germany, Saudi Arabia and Iran were purified with a package code and the obtained results were compared in this study. For purification process, both natural gases flowing in a vertical pipe and monoethanolamine (MEA) flowing as a film from the internal surface of a pipe were examined together. Both fluids were flown in a vertical and laminar regime. Binary diffusion coefficients, Schmidt numbers (Sc) and dynamical viscosities were calculated individually for three types of natural gases. It is demonstrated that the chemical absorption method by MEA process is the most appropriate method at high Damköhler (Da) numbers particularly for natural gases containing high concentrations of CO2 and H2S.

Select

Surfactant-aided hydrothermal preparation of La2-xSrxCuO4 single crystallites and their catalytic performance on methane combustion Lei Zhang, Yue Zhang, Jiguang Deng, Hongxing Dai* 2012, 21(1): 69-75.  DOI: 10.1016/S1003-9953(11)60335-6 摘要 ( 10303 )   Perovskite-like oxide La2-xSrxCuO4 (x = 0, 1) single crystallites with microrod-like morphologies and tetragonal crystal structures were prepared hydrothermally at 240 ℃ with poly(ethylene glycol) (PEG) or hexadecyltrimethyl ammonium bromide (CTAB) as a surfactant and after calcination at 850 ℃. The physicochemical properties of the materials were characterized by means of XRD, BET, SEM, TEM/SAED (selected-area electron diffraction), XPS and H2-TPR techniques. It is found that doping Sr2+ to La2CuO4 lattice enhanced the catalytic activity for methane combustion and LaSrCuO4 catalyst derived from PEG performed best. It is concluded that factors, such as adsorbed oxygen species concentration, reducibility and surface area, determined the catalytic performance of such single-crystalline materials.

Select

CH4-CO2 reforming to syngas over Pt-CeO2-ZrO2/MgO catalysts: Modification of support using ion exchange resin method Min Yang*, Haijun Guo, Yansheng Li, Qiong Dang 2012, 21(1): 76-82.  DOI: 10.1016/S1003-9953(11)60336-8 摘要 ( 13733 )   Pt-CeO2-ZrO2/MgO catalysts with 0.8 wt% Pt, 3.0 wt% CeO2 and 3.0 wt% ZrO2 were prepared by wet impregnation method. Support MgO was obtained using ion exchange resin method or using commercial MgO. XRD, BET, SEM, TEM, DTA-TG and CO2-TPD were used to characterize the catalysts. CH4-CO2 reforming to synthesis gas (syngas) was performed to test the catalytic behavior of the catalysts. The catalyst Pt-CZ/MgO-IE(D) prepared using ion exchange resin exhibits more regular structure, smaller and more unique particle sizes, and stronger basicity than the catalyst Pt-CZ/MgO prepared from commercial MgO. At 1073 K and atmospheric pressure, Pt-CZ/MgO-IE(D) catalyst has a higher activity and greater stability than Pt-CZ/MgO catalyst for CH4-CO2 reforming reaction at high gas hourly space velocity of 36000 mL/(g·h) with a stoichiometric feed of CH4 and CO2. Activity measurement and characterization results demonstrate that modification of the support using ion exchange resin method can promote the surface structural property and stability, therefore enhancing the activity and stability for CH4-CO2 reforming reaction.

Select

Production of propylene from an unconventional metathesis of ethylene and 2-pentene over Re2O7/SiO2-Al2O3 catalysts Weena Phongsawat, Benjamas Netivorruksa, Kongkiat Suriye, Siraprapha Dokjampa 2012, 21(1): 83-90.  DOI: 10.1016/S1003-9953(11)60337-X 摘要 ( 10688 )   An unconventional metathesis of ethylene and 2-pentene over Re2O7/SiO2-Al2O3 catalysts has been studied as an alternative route for the production of propylene. Complete conversion of 2-pentene and propylene yield as high as 88 wt% were obtained under mild reaction conditions at 35 ℃ and atmospheric pressure. Unlike the conventional metathesis of ethylene and 2-butenes in which isomerization is a competing side reaction, the isomerization of 1-butene product from the unconventional metathesis of ethylene and 2-pentene to 2-butenes can further react with excess ethylene in the feed, resulting in additional increase in propylene yield. The secondary metathesis reaction was found to be favored under ethylene/2-pentene (E/2P) molar ratio≥3 and gas hourly space velocity (GHSV)≤1000 h-1 at the reaction temperature of 35 ℃. No catalyst deactivation was observed during the 455 min time-on-stream under the selected reaction conditions.

Select

Effect of rapidly depressurizing and rising temperature on methane hydrate dissociation Qingbai Wu*, Yingmei Wang, Jing Zhan 2012, 21(1): 91-97.  DOI: 10.1016/S1003-9953(11)60338-1 摘要 ( 8837 )   Two methods, rapidly depressurizing to 0.1 MPa at a constant temperature and rising temperature under equilibrium P, T conditions, were used to study the dissociation of pure CH4 hydrate formed below the ice point. At a constant temperature with rapidly depressurizing to 0.1 MPa, CH4 hydrate dissociated rapidly at initial dissociation and then the dissociation rate gradually decreased, and dissociation at temperatures of 261 to 266 K was much faster than that of 269 to 272 K, indicating anomalous preservation. Under an equilibrium P, T conditions, rising temperature had extensively controlling impact on dissociation of CH4 hydrate at equilibrium pressures of 2.25, 2.08 and 1.88 MPa. In this study, we report the effect of pressure on CH4 hydrate dissociation, especially the effect of equilibrium pressure on dissociation at various melting temperatures. And we find that the ice particles size of CH4 hydrate formed may dominant the CH4 hydrate dissociation. Dissociation of CH4 hydrate formed from ice particles of smaller than 250 μm may not have an anomalous preservation below the ice point, while particles larger than 250 μm may have more extensive anomalous preservation.

Select

CH4 dissociation on Co(0001): A density functional theory study Wei Huang*, Lulu Sun, Peide Han, Jinzhen Zhao 2012, 21(1): 98-103.  DOI: 10.1016/S1003-9953(11)60339-3 摘要 ( 10776 )   CH4 dissociation on Co(0001) surfaces is an important step, which has been investigated at the level of density functional theory. It is found that CH4 is unfavorable to adsorb on Co(0001), while CH4 favores to dissociate to CH3, CH2 and CH on Co(0001) surface by sequential dehydrogenation. In the whole process of CH4 dehydrogenation, CH4 dissociate to CH3 and H is the rate-determining step. The calculated results show that CH2 and CH exist mainly on Co(0001) surface, while the dehydrogenation of CH into C and H is difficult.