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2006, Vol. 15, No. 1　Online: 2006-03-30

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Reviews

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A history of Fischer-Tropsch Wax Upgrading at BP-from Catalyst Screening Studies to Full Scale Demonstration in Alaska John P. Collins;Joep J.H.M. Font Freide;Barry Nay 2006, 15(1): 1-10.  DOI: 摘要 ( 10131 )   PDF   Conversion of Fischer-Tropsch wax into high quality synthetic crude or finished transportation fuels such as premium diesel has been studied over the past 15 years within BP. Catalyst screening and selection was carried out in dedicated micro-reactors and pilot plants, whose designs are critical to the performance selection. Variation in catalyst composition and defining the gas to oil feed ratios with the operating temperature are a few of the parameters studied. Product selection and maximizing diesel yield combined with stability (catalyst life) were the ultimate drivers. The selected catalyst was then tested under commercial conditions in a dedicated 300 barrel per day demonstration plant. The products were also tested in engines to assess their combustion characteristics.

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Theoretical and Experimental Study on Reaction Coupling:Dehydrogenation of Ethylbenzene in the Presence of Carbon Dioxide Shuwei Chen;Zhangfeng Qin;Ailing Sun;Jianguo Wang 2006, 15(1): 11-20.  DOI: 摘要 ( 10925 )   PDF   Dehydrogenation of ethylbenzene (EB) to styrene (ST) in the presence of CO2, in which EB dehydrogenation is coupled with the reverse water-gas shift (RWGS), was investigated extensively through both theoretical analysis and experimental characterization. The reaction coupling proved to be superior to the single dehydrogenation in several respects. Thermodynamic analysis suggests that equilibrium conversion of EB can be improved greatly by reaction coupling due to the simultaneous elimination of the hydrogen produced from dehydrogenation. Catalytic tests proved that iron and vanadium supported on activated carbon or -Al2O3 with certain promoters are potential catalysts for this coupling process. The catalysts of iron and vanadium are different in the reaction mechanism, although ST yield is always associated with CO2 conversion over various catalysts. The two-step pathway plays an important role in the coupling process over Fe/Al2O3, while the one-step pathway dominates the reaction over V/Al2O3. Coke deposition and deep reduction of active components are the major causes of catalyst deactivation. CO2 can alleviate the catalyst deactivation effectively through preserving the active species at high valence in the coupling process, though it can not suppress the coke deposition.

Articles

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Synthesis Gas Production from Natural Gas on Supported Pt Catalysts Mariana M. V. M. Souza;Octavio R. Macedo Neto;Martin Schmal 2006, 15(1): 21-27.  DOI: 摘要 ( 10312 )   PDF   Auto-thermal reforming of methane, combining partial oxidation and reforming of methane with CO2 or steam, was carried out with Pt/Al2O3, Pt/ZrO2 and Pt/CeO2 catalysts, in a temperature range of 300–900 degree. The auto-thermal reforming occurs in two simultaneous stages, namely, total combustion of methane and reforming of the unconverted methane with steam and CO2, with the O2 conversion of 100% starting from 450 degree. For combination with CO2 reforming, the Pt/CeO2 catalyst showed the lowest initial activity at 800 degree, and the highest stability over 40 h on-stream. This catalyst also presented the best performance for the reaction with steam at 800 degree. The higher resistance to coke formation of the catalyst supported on ceria is due to the metal-support interactions and the higher mobility of oxygen in the oxide lattice.

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Novel MWCNT-Support for Co-Mo Sulfide Catalyst in HDS of Thiophene and HDN of Pyrrole Kunming Dong;Xiaoming Ma;Hongbin Zhang;Guodong Lin 2006, 15(1): 28-37.  DOI: 摘要 ( 9131 )   PDF   With home-made multi-walled carbon nanotubes (MWCNTs, simplified as CNTs in later text) as support, CNT-supported Co-Mo-S catalysts, denoted as x%(mass percentage)MoiCoj/CNTs, were prepared. Their catalytic performance for thiophene hydrodesulfurization (HDS) and pyrrole hydrodenitrification (HDN) reactions was studied, and compared with the reference system supported by AC. Over the 7.24%Mo3Co1/CNTs catalyst at reaction condition of 1.5 MPa, 613 K, C4H4S/H2=3.7/96.3(molar ratio) and GHSV8000 mlSTP/(g-cat·h), the specific HDS activity of thiophene reached 3.29 mmolC4H4S/(s·molMo), which was 1.32 times as high as that (2.49 mmolC4H4S/(s·molMo)) of the AC-based counterpart, and was 2.47 times as high as that (1.33 mmolC4H4S/(s·molMo)) of the catalysts supported by AC with the respective optimal Mo3Co1-loading amount, 16.90%Mo3Co1/AC. Analogous reaction-chemical behaviours were also observed in the case of pyrrole HDN. It was experimentally found that using the CNTs in place of AC as support of the catalyst caused little change in the apparent activation energy for the thiophene HDS or pyrrole HDN reaction, but led to a significant increase in the concentration of catalytically active Mo-species (Mo4+) at the surface of the functioning catalyst. On the other hand, H2-TPD measurements revealed that the CNT-supported catalyst could reversibly adsorb a greater amount of hydrogen under atmospheric pressure at temperatures ranging from room temperature to about 673 K. This unique feature would help to generate microenvironments with higher stationarystate concentration of active hydrogen-adspecies at the surface of the functioning catalyst. Both factors mentioned above were favorable to increasing the rate of thiophene HDS and pyrrole HDN reactions.

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Influence of Reaction Conditions on Methanol Synthesis and WGS Reaction in the Syngas-to-DME Process Ligang Wang;Deren Fang;Xingyun Huang;Shigang Zhang;Yue Qi;Zhongmin Liu 2006, 15(1): 38-44.  DOI: 摘要 ( 10297 )   PDF   A series of CuO-ZnO catalysts (with different Cu/Zn molar ratios) were prepared, and evaluated under the reaction conditions of syngas-to-dimethyl ether (DME) with three sorts of feed gas and different space velocity. The catalysts were characterized by X-ray diffraction (XRD) and temperatureprogrammed reduction (TPR). The experiment results showed that the reaction conditions of syngas-to- DME process greatly affected the methanol synthesis and WGS reaction. The influence caused by Cu/Zn molar ratio was quite different on the two reactions; increasing of percentage of CO2 in feed gas was unfavorable for catalyst activity, and also inhibited both reactions; enhancement of reaction space velocity heavily influenced the performance of the catalyst, and the benefits were relatively less for methanol synthesis than for the WGS reaction.

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Study on Chemisorption, Catalytic Behavior, and Stability of Supported Au Catalyst for the Propylene Epoxidation Reaction Feifei Sun;Shunhe Zhong 2006, 15(1): 45-51.  DOI: 摘要 ( 9528 )   PDF   The supported Au/TiO2 and Au/TiO2-SiO2 catalysts were prepared by deposition precipitation method. The TPD study reveals that propylene oxide competes with propylene to be adsorbed on the same adsorptive center—Tin+ site on the surface of the catalyst and that the adsorbing capacity of the catalyst for propylene oxide is larger than that for propylene. Catalytic behavior for propylene epoxidation with H2 and O2 was tested in a micro-reactor. Under typical conditions, the selectivity for propylene oxide is over 87%. The TG curves show that PO successive oxidation cause carbon deposition on the active center and deactivation of the Au catalysts. Because the amounts of Tin+ site decrease significantly, and consequently the separation between Tin+ sites increases, the Au/TiO2-SiO2 catalyst is more stable than Au/TiO2.

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Non-Oxidative Aromatization of CH4-C3H8 over La-Promoted Zn/HZSM-5 Catalysts Lihe Zheng;Dong Xuan;Jianjun Guo;Hui Lou;Xiaoming Zheng 2006, 15(1): 52-57.  DOI: 摘要 ( 9866 )   PDF   The non-oxidative aromatization of mixed CH4 with C3H8 over La-promoted Zn/HZSM-5 catalysts was studied in a fixed-bed reactor at 823 K with space velocity 600 h-1 and CH4/C3H8 (molar ratio)=5:1. The propane conversion and the aromatic selectivities were up to 99% and 60% over the catalyst respectively, while methane conversion had an induction period with the highest conversion of 30%. The structure and surface acidity of the catalysts were characterized by XRD, NH3-TPD and TG-DTA. The influences of reaction and regenerative conditions on the activity and selectivity were also investigated.

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Preparation and Characterization of Single-Phase Perovskite La0.6Sr0.4Co0.8Fe0.2O3-δ Wenhui Yuan;Xiaofang Hu;Li Li 2006, 15(1): 58-62.  DOI: 摘要 ( 8761 )   PDF   Single-phase perovskite La0.6Sr0.4Co0.8Fe0.2O3-δ has been successfully prepared by using citrate-EDTA complexation method at relatively low calcination temperature. The structure and thermal decomposition process of the complex precursor have been investigated by means of differential scanning calorimetry-thermal gravimetric analysis (DSC/TGA), X-ray diffraction (XRD), and Fourier transform infrared spectroscopic (FT-IR) measurements. The precursor decomposed completely and started to form perovskite-type oxide above 420 degree. according to the differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA) results. Single-phase perovskite La0.6Sr0.4Co0.8Fe0.2O3-δ obtained has been confirmed from the XRD pattern, and no peak of SrCO3 was found by XRD of the oxides synthesized at a relatively low temperature of 800 degree. The reducibility of La0.6Sr0.4Co0.8Fe0.2O3-δ was also characterized by the temperature programmed reduction (TPR) technique. Disk shaped dense La0.6Sr0.4Co0.8Fe0.2O3-δ membrane was prepared by the isostatical pressing method. The oxygen flux rate of dense La0.6Sr0.4Co0.8Fe0.2O3-δ membrane was (2.8–18)×10.8 mol/(cm2 ·s) in the temperature range of 800–1000 degree.

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Study on Catalytic Wet Oxidation of H2S into Sulfur on Fe/Cu Catalyst Junfeng Zhang;Zhiquan Tong 2006, 15(1): 63-69.  DOI: 摘要 ( 11038 )   PDF   A wet catalytic oxidation at room temperature was investigated with solution containing ferric, ferrous and cupric ions for H2S removal. The experiments were carried out in a two step process, and the results obtained show that the removal efficiency of H2S can always reach 100% in a 300 mm scrubbing column with four sieve plates, and the regeneration of ferric ions in 200 mm bubble column can match the consumed ferric species in absorption. Removal of H2S, production of elemental sulfur and regeneration of ferric, cupric ions can all be accomplished at the same time. No raw material is consumed except O2 in flue gas or air, the process has no secondary pollution and no problem of catalyst degradation and congestion.

Communctions

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Dehalogenation of Aryl Halides Catalyzed by Montmorillonite Immobilized Bimetal Catalyst in Aqueous System Erli Zheng;Xuezhong Zheng 2006, 15(1): 70-72.  DOI: 摘要 ( 6409 )   PDF   A novel bisupported bimetal catalyst PVP-PdCl2-FeSO4/Al-Mont-PEG600 was prepared by immobilization of PVP (poly (N-vinyl-2-pyrrolidone)) supported bimetallic catalyst using alumina pillared inartificial montmorillonite as the carrier. This catalyst has good dehalogenation activity and selectivity to aryl halides—o-chlorotoluene in aqueous system in the presence of phase transfer catalyst (PEG) and sodium formate as hydrogen source. The catalyst also shows good reusability.