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Sample records for hydrodesulfurization hds catalysts

  1. Optimization of the synthesis of alpha-MoO3 nanoribbons and hydrodesulfurization (HDS) catalyst test.

    Science.gov (United States)

    Paraguay-Delgado, F; Albiter, M A; Huirache-Acuña, R; Verde, Y; Alonso-Nuñez, G

    2007-10-01

    An optimized process for synthesis of alpha-MoO3 nanoribbons characterized by uniform morphology and composition was carried out. The optimized process turned out to be the aging of a precursor of an aqueous solution of ammonium heptamolybdate for a week under constant stirring at 333 K; followed by hydrothermal treatment for 36 h up to 48 h at 473 K. The dimensions of the nanoribbons were between 5 and 10 microm in length and a width between 100 and 600 nm. The thickness was between 60 and 200 nm. This material was tested for hydrodesulfurization (HDS) of dibenzothiophene (DBT) by in situ activation and showed its catalytic activities to be similar to those of unsupported MoS2 catalysts. The structure and morphology of these materials was characterized by analytical transmission electron microscopy, scanning electron microscopy, and X-ray diffraction using the Rietveld method to determine the quantitative crystallographic phases. A chemical semiquantitative analysis was carried out by energy dispersive spectroscopy and a qualitative analysis was carried out by electron energy loss spectroscopy.

  2. Evaluation of phase separator number in hydrodesulfurization (HDS) unit

    Science.gov (United States)

    Jayanti, A. D.; Indarto, A.

    2016-11-01

    The removal process of acid gases such as H2S in natural gas processing industry is required in order to meet sales gas specification. Hydrodesulfurization (HDS)is one of the processes in the refinery that is dedicated to reduce sulphur.InHDS unit, phase separator plays important role to remove H2S from hydrocarbons, operated at a certain pressure and temperature. Optimization of the number of separator performed on the system is then evaluated to understand the performance and economics. From the evaluation, it shows that all systems were able to meet the specifications of H2S in the desired product. However, one separator system resulted the highest capital and operational costs. The process of H2S removal with two separator systems showed the best performance in terms of both energy efficiency with the lowest capital and operating cost. The two separator system is then recommended as a reference in the HDS unit to process the removal of H2S from natural gas.

  3. Development of New Generation Catalysts for Selective Hydrodesulfurization of FCC Naphtha

    Institute of Scientific and Technical Information of China (English)

    Chu Yang; Li Mingfeng; Li Huifeng; Qu Jinhua; Nie Hong; Li Dadong

    2009-01-01

    The influence of active metal components of catalyst, additives and catalyst preparation method on the reactiv-ity of catalyst for selective hydrodesulfurization (HDS) of FCC naphtha was investigated, and the RSDS-21 catalyst with high HDS performance and the RSDS-22 catalyst with high selectivity were developed by RIPP. The composite loading of a new series of catalysts for selective HDS of FCC gasoline has demonstrated excellent desulfurization activity and selectivity and can under conventional hydrotreating conditions manufacture clean gasoline product meeting the national Ⅳ emission standard and the Euro Ⅴ emission standard with less loss in antiknock index. The finalized new series of FCC catalysts upon being adopted for selective HDS of FCC naphtha have good adaptability to different feedstocks along with good stability.

  4. Preparation of highly active AlSBA-15-supported platinum catalyst for thiophene hydrodesulfurization

    OpenAIRE

    KANDA, Yasuharu; AIZAWA, Tomohiro; Kobayashi, Takao; UEMICHI, Yoshio; NAMBA, Seitaro; SUGIOKA, Masatoshi

    2007-01-01

    The catalytic activities of various noble metals (Pt, Pd, Rh, and Ru) supported on siliceous SBA-15 and Al-containing SBA-15 (AlSBA-15) for hydrodesulfurization (HDS) of thiophene at 350 C were investigated. AlSBA-15 was prepared by a grafting method using aluminum isopropoxide (Al(OC3H7)3) hexane solution. The HDS activity of Pt/AlSBA-15 catalyst was the highest among those of various supported noble metal catalysts, and this activity was higher than that of commercial CoMo/Al2O3 HDS catalys...

  5. Hydrodesulfurization catalyst prepared by urea-matrix combustion method

    Institute of Scientific and Technical Information of China (English)

    Dongmei Jiao; Yeyong Ma; Fahai Cao

    2012-01-01

    Co-Mo/γ-Al2O3-TiO2 hydrodesulfurization (HDS) catalyst samples prepared by a urea matrix combustion (UMxC) method,were evaluated in a stainless tubular fixed-bed reactor,with thiophene,benzothiophene and dibenzothiophene in xylene as model feedstocks.The samples were pre-sulfurized using a cyclohexane solution of 3% CS2 and then tested for the HDS reaction.The test results were compared with catalysts prepared by conventional methods involving sequential impregnation (SI) and co-impregnation (CI).The catalysts were characterized using X-ray diffraction (XRD),laser Raman spectroscopy (LRS),high resolution transmission electron microscopy (HRTEM) and N2 physisorption,showing that the UMxC catalyst had higher pore volume and surface area than those prepared by the CI and SI methods.The UMxC method increased metal loading and avoided formation of inert phase,e.g.,β-CoMoO4,for the HDS reaction,suggesting that UMxC method is superior to the conventional impregnation techniques.TiO2 promoter made particles on the catalyst surface closer and alleviated the interaction between molybdenum oxide and the support,and facilitated the formation of well-dispersed Co- and Mo-oxo species on catalyst surface,thus resulting in higher HDS catalytic activity than pure -γ-Al2O3 support without modifiers.Consequently,the addition of TiO2 obviously improved the HDS conversion of dibenzothiophene.

  6. HDS and deep HDS activity of CoMoS-mesostructured clay catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Carrado, K.A.; Castagnola, N. [Chemistry Division, 9700 S. Cass Avenue, Argonne National Laboratory, Argonne, IL 60439 (United States); Kim, J.H.; Song, C.S. [Clean Fuels and Catalysis Program, The Energy Institute and Department of Energy and Geo-Environmental Engineering, 206 Hosler Building, Pennsylvania State University, University Park, PA 16802 (United States); Marshall, C.L.; Schwartz, M.M. [Chemical Engineering Division, 9700 S. Cass Avenue, Argonne National Laboratory, Argonne, IL 60439 (United States)

    2006-09-15

    The goal of this work is to identify more promising supports from synthetic clay materials to advance hydrotreating catalyst development. Silica sol can be used as the silicon-containing starting material when creating nanoporous layered silicate catalysts with a certain portion of unreacted sol particles incorporated into the final matrix. The resulting structure then has mesoporosity and a unique morphology. Hectorite-based clays have been prepared using different silica sols in order to ascertain the importance of sol characteristics on the final matrix. Several techniques have been applied to characterize the materials, including XRD, TGA, N{sub 2} porosimetry, and TEM. For hydrodesulfurization (HDS), the conversion of dibenzothiophene (DBT) to biphenyl was examined at 400{sup o}C using CoMoS-loaded mesostructured clay supports. No hydrogenation or hydrocracking was observed with any of the clay supports. The most active clay was derived from Ludox silica sol AS-30 with an activity of 65% DBT conversion and 100% selectivity to biphenyl (BP). For comparison, a reference commercial catalyst displayed 94% BP selectivity. For deep HDS, the conversion of 4,6-dimethyldibenzothiophene was tested at 325 and 350{sup o}C. At 325{sup o}C, conversions are 92% of commercial catalysts for a CoMoS-loaded mesostructured clay derived from Ludox AM-30 silica sol. A commercially available synthetic hectorite called laponite has very low activity, indicating that the unique morphology of the mesostructured clays is important. Hydrogenolysis vs. hydrogenation pathways are compared for the deep HDS reaction. HR-TEM of the most active deep HDS catalyst revealed a multilayered MoS{sub 2} morphology. (author)

  7. Peak overlaps and corresponding solutions in the X-ray photoelectron spectroscopic study of hydrodesulfurization catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Qiu Limei [Research Institute of Petroleum Processing, SINOPEC, 18 Xue Yuan Road, 100083 Beijing (China); Xu Guangtong, E-mail: gtxu@sina.com [Research Institute of Petroleum Processing, SINOPEC, 18 Xue Yuan Road, 100083 Beijing (China)

    2010-03-15

    Al{sub 2}O{sub 3}-SiO{sub 2}-based Co(Ni)-Mo(W)-S catalysts are widely investigated hydrodesulfurization (HDS) catalysts in recent decades. XPS is a suitable technique to detect the surface properties of HDS catalysts. Typical overlapping spectra in the XPS analysis of HDS catalysts, such as Mo3d and S2s, Si2p and bremsstrahlung-induced Al KL{sub 23}L{sub 23} using nonmonochromatic AlK{alpha} source, W4f and W5p{sub 3/2}, as well as the disturbance of Auger lines on Ni2p and Co2p, are carefully studied in the present paper. Besides, effective methods to overcome the influence of peak overlaps are illustrated. These results would provide basic and important information in interpreting XPS results of HDS catalysts.

  8. On-line regeneration of hydrodesulfurization catalyst

    Science.gov (United States)

    Preston, Jr., John L.

    1980-01-01

    A hydrotreating catalyst is regenerated as it concurrently hydrotreats a hydrocarbon fuel by introducing a low concentration of oxygen into the catalyst bed either continuously or periodically. At low oxygen concentrations the carbon deposits on the catalyst are burned off without harming the catalyst and without significantly affecting the hydrotreating process. In a preferred embodiment the hydrotreating process is hydrodesulfurization, and regenerating is done periodically with oxygen concentrations between 0.1 and 0.5 volume percent.

  9. X-ray Spectroscopy and Microscopy of Cobalt and Nickel in CoMoS and CoNiMoS Hydrodesulfurization Catalysts

    NARCIS (Netherlands)

    Al Samarai, M.

    2016-01-01

    In recent years, there has been growing interest in understanding the catalysis background for the hydrodesulfurization (HDS) reaction. Strict regulations have been introduced surrounding the production of ultra-low-sulfur fuels (<10 ppm), and as a result, the HDS catalyst has become a favorite topi

  10. X-ray Spectroscopy and Microscopy of Cobalt and Nickel in CoMoS and CoNiMoS Hydrodesulfurization Catalysts

    NARCIS (Netherlands)

    Al Samarai, M.|info:eu-repo/dai/nl/345517407

    2016-01-01

    In recent years, there has been growing interest in understanding the catalysis background for the hydrodesulfurization (HDS) reaction. Strict regulations have been introduced surrounding the production of ultra-low-sulfur fuels (<10 ppm), and as a result, the HDS catalyst has become a favorite topi

  11. Nanoparticles of TiAlZr mixed oxides as supports of hydrodesulfurization catalysts: Synthesis and characterization

    Energy Technology Data Exchange (ETDEWEB)

    Kraleva, E., E-mail: ekraleva@gmail.com [Institute of Biodiversity and Ecosystems Research, Bulgarian Academy of Sciences, Sofia, Gagarin st.2 (Bulgaria); Spojakina, A. [Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria); Saladino, M.L. [Dipartimento di Chimica ' S. Cannizzaro' , Universita di Palermo and INSTM-Udr Palermo, Parco d' Orleans II Viale delle Scienze pad 17, I-90128 Palermo,Italy (Italy); Caponetti, E. [Dipartimento di Chimica ' S. Cannizzaro' , Universita di Palermo and INSTM-Udr Palermo, Parco d' Orleans II Viale delle Scienze pad 17, I-90128 Palermo,Italy (Italy); Centro Grandi Apparecchiature - UniNetLab, Universita di Palermo, Via F. Marini 14, I-90128 Palermo (Italy); Nasillo, G. [Centro Grandi Apparecchiature - UniNetLab, Universita di Palermo, Via F. Marini 14, I-90128 Palermo (Italy); Jiratova, K. [Institute of Chemical Process Fundamentals, 16502 Prague 6 (Czech Republic)

    2012-02-05

    Highlights: Black-Right-Pointing-Pointer Preparation of ternary mixed oxide by sol-gel method. Black-Right-Pointing-Pointer Catalytic properties of the three-mixed oxides. Black-Right-Pointing-Pointer Heteropolyacid H{sub 3}PMo{sub 12}O{sub 40} and its cobalt salt Co{sub 1.5}PMo{sub 12}O{sub 40} that of active components in catalytic systems for thiophene hydrodesulfurization (HDS). - Abstract: TiAlZr mixed oxides, synthesized using sol-gel method, were characterized and used as supports of hydrodesulfurization catalysts (12 wt% Mo) prepared by impregnation either with molybdenum heteropolyacid H{sub 3}PMo{sub 12}O{sub 40} or its cobalt salt Co{sub 1.5}PMo{sub 12}O{sub 40}. Structure, morphology and textural properties of oxides and catalysts were characterized using X-ray powder diffraction (XRD), Raman spectroscopy, Nitrogen adsorption porosimetry, TEM-EDS, temperature-programmed desorption (TPD) and temperature-programmed reduction (TPR) techniques. Activity of the catalytic systems was tested in thiophene hydrodesulfurization (HDS). No formation of a new oxide phase was revealed in the synthesized mixed materials. However the effect of separated oxides on the structure of ternary oxides was observed. Maximum in HDS activity of Mo containing samples was determined by optimum content of alumina in the mixed oxides. Incorporation of cobalt into the heteropolyacid increased the HDS activity about two times and masked the effect of the support composition.

  12. States of carbon nanotube supported Mo-based HDS catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Shang, Hongyan; Liu, Chenguang; Xu, Yongqiang [Key Laboratory of Catalysis, CNPC, College of Chemistry and Chemical Engineering, University of Petroleum, Dongying 257061 (China); Qiu, Jieshan [Carbon Research Laboratory, Center for Nano Materials and Science, Dalian University of Technology, 158 Zhongshan Road, P. O. Box 49, Dalian 116012 (China); Wei, Fei [Department of Chemical Engineering, Tsinghua University, Being, 100084 (China)

    2007-02-15

    As HDS catalysts, the supported catalysts including oxide state Mo, Co-Mo and sulfide state Mo on carbon nanotube (CNT) were prepared, while the corresponding supported catalysts on {gamma}-Al{sub 2}O{sub 3} were prepared as comparison. Firstly, the dispersion of the active phase and loading capacity of Mo species on CNT was studied by XRD and the reducibility properties of Co-Mo catalysts in oxide state over CNTs were investigated by TPR while the sulfide Co-Mo/CNT catalysts were characterized by XRD and LRS techniques. Secondly, the activity and selectivity of hydrodesulfurization (HDS) of dibenzothiophene with Co-Mo/CNT and Co-Mo/{gamma}-Al{sub 2}O{sub 3} were studied. It has been found that the main active molybdenum species in the oxide state MoO{sub 3}/CNT catalysts were MoO{sub 2}, rather than MoO{sub 3} as generally expected. The maximum loading before formation of the bulk phase was lower than 6%m (calculated in MoO{sub 3}). The TPR studies revealed that that active species in oxide state Co-Mo/CNT catalysts were more easily reduced at relatively lower temperatures in comparison to those in Co-Mo/{gamma}-Al{sub 2}O{sub 3}, indicating that the CNT support promoted the reduction of active species. Among 0-1.0 Co/Mo atomic ratio on Co-Mo/CNT, 0.7 has the highest reducibility. It shows that the Co/Mo atomic ratio has a great effect on the reducibility of active species on CNT and their HDS activities and that the incorporation of cobalt improved the dispersion of molybdenum species on CNT and mobilization. It was also found that re-dispersion could occur during the sulfiding process, resulting in low valence state Mo{sub 3}S{sub 4} and Co-MoS{sub 2.17} active phases. The HDS of DBT showed that Co-Mo/CNT catalysts were more active than Co-Mo/{gamma}-Al{sub 2}O{sub 3} and the hydrogenolysis/hydrogenation selectivity of Co-Mo/CNT catalyst was also much higher than Co-Mo/{gamma}-Al{sub 2}O{sub 3}. For the Co-Mo/CNT catalysis system, the catalyst with Co/Mo atomic

  13. Sulfur-33 Isotope Tracing of the Hydrodesulfurization Process: Insights into the Reaction Mechanism, Catalyst Characterization and Improvement.

    Science.gov (United States)

    Sushkevich, Vitaly L; Popov, Andrey G; Ivanova, Irina I

    2017-08-28

    The novel approach based on (33) S isotope tracing is proposed for the elucidation of hydrodesulfurization (HDS) mechanisms and characterization of molybdenum sulfide catalysts. The technique involves sulfidation of the catalyst with (33) S-isotope-labeled dihydrogen sulfide, followed by monitoring the fate of the (33) S isotope in the course of the hydrodesulfurization reaction by online mass spectrometry and characterization of the catalyst after the reaction by temperature-programmed oxidation with mass spectrometry (TPO-MS). The results point to different pathways of thiophene transformation over Co or Ni-promoted and unpromoted molybdenum sulfide catalysts, provide information on the role of promoter and give a key for the design of new efficient HDS catalysts. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. States of Carbon Nanotube Supported Mo-Based HDS Catalysts

    Institute of Scientific and Technical Information of China (English)

    Hongyan Shang; Chenguang Liu; Yongqiang Xu; Jieshan Qiu; Fei Wei

    2006-01-01

    The dispersion of the active phase and loading capacity of the Mo species on carbon nanotube (CNT) was studied by the XRD technique. The reducibility properties of Co-Mo catalysts in the oxide state over CNTs were investigated by TPR, while the sulfided Co-Mo/CNT catalysts were characterized by means of the XRD and LRS techniques. The activity and selectivity with respect to the hydrodesulfurization (HDS) performances on carbon nanotube supported Co-Mo catalysts were evaluated. It was found that the main active molybdenum species in the oxide state MoO3/CNT catalysts were MoO2, but not MoO3, as generally expected. The maximum loading before the formation of the bulk phase was lower than 6% (percent by mass, based on MoO3). TPR studies revealed that the active species in the oxide state Co-Mo/CNT catalysts were reduced more easily at relatively lower temperatures in comparison to those of the Co-Mo/γ-Al2O3 catalysts, indicating that the CNT support promoted or favored the reduction of the active species. The active species of a Co-Mo-0.7/CNT catalyst were more easily reduced than those of the Co-Mo/CNT catalysts with Co/Mo atomic ratios of 0.2, 0.35, and 0.5, respectively, suggesting that the Co/Mo atomic ratio has a great effect on the reducibility of the active species. It was found that the incorporation of cobalt improved the dispersion of the molybdenum species on the support, and a phenomenon of mobilization and re-dispersion had occurred during the sulfurization process, resulting in low valence state Mo3S4 and Co-MoS2.17 active phases. HDS measurements showed that the Co-Mo/CNT catalysts were more active than the Co-Mo/γ-Al2O3 ones for the desulfurization of DBT, and the hydrogenolysis/hydrogenation selectivity of the Co-Mo/CNT catalysts was also much higher than those of the Co-Mo/γ-Al2O3. The Co-Mo/CNT catalyst with a Co/Mo atomic ratio of 0.7 showed the highest activity, whereas the catalyst with a Co/Mo atomic ratio of 0.35 had the highest selectivity.

  15. Development of FHDS Type Catalyst for Deep Hydrodesulfurization of Diesel Fuel

    Institute of Scientific and Technical Information of China (English)

    Guo Rong; Yao Yunhai; Zhou Yong

    2005-01-01

    The FHDS type catalyst for deep hydrodesulfurization (HDS) of diesel fuel is a highactivity catalyst developed by FRIPP in order to meet the requirements of Chinese refiners for production of low-sulfur clean diesel fuel containing less than 300 ppm of sulfur. The FH-DS type catalyst has excellent HDS and HDN activity thanks to modification of alumina through incorporating additives, optimization of catalyst preparation and optimal combination of active ingredients.Under low pressure the HDS activity of this catalyst is by 50% higher than that of domestic reference catalysts available in the market and is slightly better than that of foreign reference catalyst. When this catalyst is used for manufacture of clean ultra-low sulfur diesel (containing <30 ppm of S), its volumetric relative desulfurization activity is 46% higher than that of foreign reference catalyst, and this catalyst is an excellent catalyst for manufacture of low-sulfur clean diesel fuel derived from imported high-sulfur Kuwaiti and Arabian crude oils.

  16. Deep Hydrodesulfurization of Diesel Fuel over Diatomite-dispersed NiMoW Sulifde Catalyst

    Institute of Scientific and Technical Information of China (English)

    Liu Di; Liu Chenguang

    2013-01-01

    Diatomite-dispersed NiMoW catalyst was prepared and characterized,and the activity of catalyst samples was tested during the HDS reaction of FCC diesel. Sulfur compounds in the feedstock and the hydrogenated products obtained over different catalysts were determined by GC-PFPD. The test results showed that the diatomite-dispersed NiMoW catalyst had high hydrodesulfurization activity for FCC diesel, which could be contributed to the excellent hydrogenation perfor-mance of the said catalyst. Characterization of catalyst by TEM and XRD indicated that the diatomite-dispersed NiMoW catalyst possessed higher layer stacking, larger curvature of MoS2 or WS2, and segregated Ni3S2 crystals relative to the sup-ported catalyst. This kind of structure leads to high hydrogenation activity of the diatomite-dispersed NiMoW catalyst.

  17. Mesoporous synthetic clays : synthesis, characterization, and use as HDS catalyst supports.

    Energy Technology Data Exchange (ETDEWEB)

    Bloomquist, C. A. A.; Carrado, K. A.; Marshall, C. L.; Seifert, S.; Wei, D.; Xu, L.

    1999-08-10

    Mesoporous synthetic clays (MSCs) are obtained when polymer-containing silicate gels are hydrothermally crystallized to form layered magnesium silicate hectorite clays containing polymers that are incorporated in situ. Polyvinylpyrrolidone of several average molecular weights ranging from 10K to 1.3M, in gel loadings varying from 5-30 wt%, were used. The organic polymer template molecules were removed from synthetic polymer-clay complexes via calcination. Pore radii, surface areas, and pore volumes of the resulting porous inorganic networks were then measured. For the most part there is a direct correlation between both PVP molecular weight and polymer loading on the diameter of the average pore. In addition to conventional techniques, the polymer-clay materials were also characterized by small angle x-ray scattering to ascertain the disposition of the polymeric matrix. The MSC materials after calcination were examined as potential supports for hydrodesulfurization (HDS). They were loaded with a bimetallic Co/Mo catalyst system for comparison with a commercial Co/Mo alumina catalyst. Dibenzothiophene (DBT) diluted with hexadecane (0.75 wt% S) was utilized as a liquid feed for the HDS tests. This feed was chosen as a deep HDS test of a heavy model oil. The pore diameters of the MSC catalysts were found to have a strong effect on both the HDS activity and selectivity.

  18. Highly dispersed CoMoS phase on titania nanotubes as efficient HDS catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Cortes-Jacome, M.A.; Escobar, J.; Angeles Chavez, C.; Lopez-Salinas, E.; Romero, E.; Ferrat, G.; Toledo-Antonio, J.A. [Molecular Engineering Program, Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas 152, San Bartolo Atepehuacan, G.A. Madero, 07730 Mexico, D.F. (Mexico)

    2008-01-15

    Nanotubular titania (NT) to be used as support for CoMo-based hydrodesulfurization (HDS) catalyst was synthesized and characterized by various techniques. NT annealed at 400 C (under nitrogen) was constituted by nanotubes of {proportional_to}5.5 nm (internal diameter) and retained 236 m{sup 2}/g of surface area. Mo at 3 atoms/nm{sup 2} (nominal loading) and cobalt at Co/(Co + Mo) = 0.3 were impregnated under nearly neutral, acidic or basic media. By XPS analyses of NT-supported sulfided catalysts, highly dispersed MoS{sub 2} particles of low stacking degree (1-2 slabs) aligned along the nanotubes were observed by HR-TEM in all sulfided materials. The CoMo catalysts supported on nanostructured titania had dibenzothiophene (DBT) HDS activity (in pseudo first order kinetic constant basis) values {proportional_to}1.35 and {proportional_to}1.7 times (Mo impregnated under near neutral and basic media, respectively) higher to that of a commercial reference with alumina carrier. According to shifts to higher binding energy of the Co 2p peak corresponding to sulfided cobalt (as determined by XPS), MoS{sub 2} dispersed on NT support could be efficiently promoted by Co (''CoMoS'' phase formation), opening the possibility of developing new highly active HDS catalysts. (author)

  19. New insides in the characterization of HDS industrial catalysts by HAADF-STEM

    Science.gov (United States)

    Del Angel, Paz; Ponce, Arturo; Arellano, Josefina; Yacaman, Miguel J.; Hernandez-Pichardo, Martha; Montoya, J. Ascencion; Escobar, Jose

    2015-03-01

    Hydrodesulfurization (HDS) catalysts are of great importance in the petroleum industry. Transition metal sulphides catalysts of Ni(Co)Mo(W)/Al2O3 are widely used for hydrotreating reactions, like hydrodenitrogenation and HDS. One of the main issue in these catalysts is to understand the mechanism of the reaction, where MoS2 plays the most important role in the catalytic activity. We studied an industrial NiMo/Alumina sulfide catalyst highly active by using aberration-corrected HAADF-STEM techniques. The used catalysts was a state-of- the art commercial nickel-molybdenum alumina-supported formulation, including organic agent modifier. This type of material belongs to a novel family of catalysts specially designed for ultra-low sulfur production from straight-run gas oil (SRGO), cycle oil, coker gas oil, or their combinations at operating conditions of commercial interest in hydrotreating units at industrial scale. Aberration corrected HAADF-STEM allowed to observe the nanostructure and location of MoS2 and his interaction with the alumina. The results indicate that the MoS2 is highly dispersed on the alumina, however the location of Ni is one of the task of this kind of catalyst.

  20. The functionalities of Pt/{gamma}-Al{sub 2}O{sub 3} catalysts in simultaneous HDS and HDA reactions

    Energy Technology Data Exchange (ETDEWEB)

    V.G. Baldovino-Medrano; Sonia A. Giraldo; Aristobulo Centeno [Universidad Industrial de Santander (UIS), Bucaramanga (Colombia). Centro de Investigaciones en Catalisis (CICAT)

    2008-08-15

    A Pt/{gamma}-Al{sub 2}O{sub 3} catalyst was tested in simultaneous hydrodesulfurization (HDS) of dibenzothiophene and hydrodearomatization (HDA) of naphthalene reactions. Samples of it were subjected to different pretreatments: reduction, reduction-sulfidation, sulfidation with pure H{sub 2}S and non-activation. The reduced catalyst presented the best performance, even comparable to that of Co(Ni)Mo catalysts. All catalyst samples were selective to the HDS reaction over HDA, and to the direct desulfurization pathway of dibenzothiophene HDS over the hydrogenation reaction pathway of HDS. The effect of H{sub 2}S partial pressure on the functionalities of the reduced Pt/{gamma}-Al{sub 2}O{sub 3} catalyst was studied. The results showed that an increase in H{sub 2}S partial pressure does not cause poisoning, but an inhibition effect, without changing the catalyst selectivity. Accordingly, the activity trends were ascribed to adsorption differences between the different reactive molecules over the same catalytic active site. TPR characterization along with a thermodynamics analysis showed that the active phase of reduced Pt/{gamma}-Al{sub 2}O{sub 3} is constituted by Pt{sup 0} particles. However, presulfidation of the catalyst leads to a mixture of PtS and Pt{sup 0}which has a negative effect on the catalytic performance without changing catalyst functionalities. 61 refs., 4 figs., 1 tab.

  1. Mössbauer Spectroscopy Investigation and Hydrodesulfurization Properties of Iron–nickel Phosphide Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Gaudette, Amy F.; Burns, Autumn W.; Hayes, John R.; Smith, Mica C.; Bowker, Richard H.; Seda, Takele; Bussell, Mark E.

    2010-05-25

    Unsupported and silica-supported FexNi2-xPy catalysts having a range of metal compositions (0 < x 6 2.0) were investigated using Mössbauer spectroscopy, and the results correlated with the surface and hydrodesulfurization (HDS) properties of the supported catalysts. Mössbauer spectroscopy permits determination of the relative site occupancy of Fe atoms in tetrahedral (M(1)) and pyramidal (M(2)) sites in the FexNi2-xPy materials. Fe atoms preferentially occupy M(2) sites for materials with significant Fe contents (x > ~0.60), but the Fe site preference reverses as the Fe content decreases (x < ~0.60). Similar occupation trends are observed for the unsupported and silica-supported FexNi2-xPy materials. Thiophene HDS measurements of the FexNi2-xPy/SiO2 catalysts revealed catalysts with high Fe contents (0.80 6 x 6 2.00) to have low activities, while the activities of Ni-rich catalysts increased dramatically with increased Ni content (0.03 6 x 6 0.60). The highest HDS activity was measured for a catalyst having a nominal precursor composition of Fe0.03Ni1.97P2.00/SiO2; this catalyst was 40% more active than a optimized nickel phosphide catalyst prepared from a precursor having a nominal composition of Ni2.00P1.60/SiO2. The 25 wt.% Fe0.03Ni1.97P2.00/SiO2 catalyst also had a dibenzothiophene HDS activity just over 10% higher than that of the 25 wt.% Ni2.00P1.60/SiO2 catalyst at 548 K. The trend of increasing HDS activity for the FexNi2-xPy/ SiO2 catalysts correlates with preferential Fe occupation of M(1) sites (and, therefore, Ni occupation of M(2) sites). Supported by X-ray photoelectron spectroscopy and oxygen chemisorption measurements, we conclude that the high activity of Ni-rich FexNi2-xPy/SiO2 catalysts can be traced to a high surface density of Ni in M(2) sites that are resistant to site blockage due to S incorporation.

  2. Weakening internal diffusion effect in selective hydrodesulfurization of FCC gasoline by novel designed eggshell CoMoS/Al2O3 catalysts

    Institute of Scientific and Technical Information of China (English)

    Bin Liu; Yongming Chai; Yajing Wang; Yunqi Liu; Chenguang Liu

    2012-01-01

    A simple method for preparation of presulfided eggshell CoMoS/γ-Al2O3 catalysts with sharp boundary is developed,through which the eggshell thicknesses of Co and Mo could be easily regulated by controlling the impregnation time.According to the results characterized by EDS,XRD,HRTEM and FT-IR of adsorbed CO,the active component structures,the nature and/or the amount of active sites on the eggshell catalyst are similar to these on the uniform catalyst.The evaluation results of the catalytic performance in selective hydrodesulfurization (HDS)of FCC gasoline show the presence of significant internal diffusion inhibition effect on HDS of S-compounds especially in the uniform catalyst.Compared with uniform catalyst,the eggshell catalyst could remarkably reduce such an internal diffusion inhibition effect due to a shortened diffusion path of the reactants,thus showing higher HDS activity and selectivity.

  3. Hydrodesulfurization and Hydrodenitrogenation Kinetics of a Heavy Gas Oil over NiMo/Al2O3 Catalysts

    Institute of Scientific and Technical Information of China (English)

    DUAN Ai-jun; XU Chun-ming; LIN Shi-xiong; CHUNG Keng H

    2005-01-01

    The kinetics of Athabasca bitumen derived heavy gas oil over NiMo/Al2O3 catalysts were studied in a JQ-II high-pressure microscale hydrotreator unit under different operation conditions, including temperature, pressure, H/O ratio and LHSV. The multi-parameter models of hydrodesulfurization and hydrodenitrogenation were proposed. The model parameters verify that the HDS and HDN reactions follow 1.5-order and 1.6-order kinetic rules, respectively. The kinetic activation energies of HDN and HDS over Com, Hom1 and Hom2 show that homemade catalysts exhibit higher activities in HDN than commercial catalyst. Using the multi-parameter kinetic model to predict the contents of sulfur and nitrogen in products is in good agreement with the experimental data.

  4. From biomass to fuels : hydrotreating of oxygen-containing feeds on a CoMo/Al2O3 hydrodesulfurization catalyst

    OpenAIRE

    Viljava, Tuula-Riitta

    2001-01-01

    Biomass is a renewable alternative to fossil raw materials in the production of liquid fuels and chemicals. Liquefied biomass contains an abundance of oxygen-containing molecules that need to be removed to improve the stability of the liquids. A hydrotreating process, hydrodeoxygenation (HDO), is used for the purpose. Hydrodeoxygenation is similar to the hydrodesulfurization (HDS) process used in oil refining, relying upon a presulfided CoMo/γ-Al2O3 catalyst. The stability of the sulfided cat...

  5. Dibenzothiophene hydrodesulfurization over Ru promoted alumina based catalysts using in situ generated hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Muhammad, Yaseen; Shen, Chong; Li, Chunxi [State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Lu, Yingzhou [College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029 (China)

    2011-02-15

    Catalytic hydrodesulfurization (HDS) of dibenzothiophene (DBT) was carried out in a temperature range of 320-400 C using in situ generated hydrogen coupled with the effect of selected organic additives for the first time. Four kinds of alumina based catalysts i.e. Co-Mo/Al{sub 2}O{sub 3}, Ni-Mo/Al{sub 2}O{sub 3}, Ru-Co-Mo/Al{sub 2}O{sub 3} and Ru-Ni-Mo/Al{sub 2}O{sub 3} were used for the desulfurization process, which were prepared following incipient impregnation method with fixed metal loadings (wt.%) of Co, Ni, Mo and Ru. The surface area, average pore diameter and pore volume distribution of the fresh and used catalysts were measured by N{sub 2} adsorption using BET method. Catalytic activity was investigated in a batch autoclave reactor in the complete absence of external hydrogen gas. Addition and mutual reaction of specific quantities of water and ethanol provided the necessary in situ hydrogen for the desulfurization reaction. Organic additives like diethylene glycol (DEG), phenol, naphthalene, anthracene, o-xylene, tetralin, decalin and pyridine did impinge the HDS activity of the catalysts in different ways. Liquid samples from reaction products were quantitatively analyzed by HPLC technique while qualitative analyses were made using GC-MS. Both of these techniques showed that Ni-based catalysts were more active than Co-based ones at all conditions. Moreover, incorporation of Ru to both Co and Ni-based catalysts greatly promoted desulfurization activity of these catalysts. DBT conversion of up to 84% was achieved with Ru-Ni-Mo/Al{sub 2}O{sub 3} catalyst at 380 C temperature for 11 h. Catalyst systems followed the HDS activity order as: Ru-Ni-Mo/Al{sub 2}O{sub 3}> Ni-Mo/Al{sub 2}O{sub 3}> Ru-Co-Mo/Al{sub 2}O{sub 3}> Co-Mo/Al{sub 2}O{sub 3} at all conditions. Cost effectiveness, mild operating conditions and reasonably high catalytic activity using in situ generated hydrogen mechanism proved our process to be useful for HDS of DBT. (author)

  6. Trends in hydrodesulfurization catalysis based on realistic surface models

    DEFF Research Database (Denmark)

    Moses, P.G.; Grabow, L.C.; Fernandez Sanchez, Eva

    2014-01-01

    Trends in hydrodesulfurization (HDS) activity are investigated on the basis of surface properties calculated by density functional theory for a series of HDS catalysts. It is shown that approximately linear correlations exist between HS group binding energies and activation barriers of key elemen...

  7. Influence of double promotion on HDS catalysts prepared by urea-matrix combustion synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Cortes, Sergio L. [Laboratorio de Cinetica y Catalisis, Departamento de Quimica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela); Xiao, Tian-Cun; Lin, Tsung-Wu; Green, Malcolm L.H. [Wolfson Catalysis Centre, Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR (United Kingdom)

    2006-04-11

    The stringent environmental regulations in the US, Japan and Europe are requiring significant improvement in the quality of transportation fuels. A new strategy based on urea-matrix combustion method for the synthesis of alumina-supported molybdate-based mixed oxides (i.e., bimetallic and trimetallic oxides) has been applied. This permits to control the alumina-mixed oxide interaction and therefore the HDS catalytic behaviour. The oxidic and sulfurized states of the HDS catalysts were characterized by X-ray diffraction (XRD), laser Raman spectroscopy (LRS), temperature-programmed reduction (TPR) and high resolution transmission electron microscopy (HRTEM). Catalyst performance was evaluated using a tubular fixed-bed reactor and the hydrodesulfurization of thiophene under normal pressure as model reaction. It has been found that Ni-promoted alumina-supported MoO{sub 3} catalyst precursor presented a non well-ordered structure of Ni-Mo phase supported on alumina surface. However, when cobalt was added to Ni-Mo precursor the {beta}-isomorph stability was significantly improved and the formation of alumina-supported {beta}-Co{sub 0.5}Ni{sub 0.5}MoO{sub 4} was observed. The activation treatments markedly affect the catalyst structure and hence the HDS catalytic performance. The catalyst series pretreated in H{sub 2}S-H{sub 2} was 2-3 times more active than those C{sub 4}H{sub 4}S-H{sub 2}-pretreated catalysts and ca. 2-10 times more active than the pre-reduced samples. A significantly greater HDS activity of H{sub 2}S-H{sub 2}-pretreated Co{sub 0.5}Mg{sub 0.5}MoS{sub x}/{gamma}-Al{sub 2}O{sub 3} catalyst was observed, which is attributed to the fact that both promoters are into the same network interacting directly with the molybdenum. This feature hinders not only the segregation of cobalt sulfide, but also the formation of long MoS{sub 2} slabs. (author)

  8. Thiophene hydrodesulfurization over CoMo/Al2O3-CuY catalysts: Temperature effect study

    Directory of Open Access Journals (Sweden)

    Yamina Boukoberine

    2016-09-01

    Full Text Available CoMo/γ-Al2O3-CuY catalysts are prepared by physically mixing CoMo/γ-Al2O3 catalyst with Cu-exchanged Y zeolite. The CuY zeolite is prepared by the solid state ion exchange technique. The thiophene hydrodesulfurization is performed in a fixed bed reactor at high temperature and atmospheric pressure. The results show that the presence of CuY zeolite particles in CoMo/Al2O3 catalyst can have a noticeable effect on both the conversion and product selectivities. An increasing zeolite loading in catalyst results in a decrease of the thiophene HDS activity. This decrease is probably caused by the formation of heavy compounds and the deactivation of the zeolite at high temperatures.

  9. Preparation, characterization of Mo catalysts supported on Ni- containing calcium deficient hydroxyapatite and reactivity for the thiophene HDS reaction

    Directory of Open Access Journals (Sweden)

    Cherif A.

    2013-09-01

    Full Text Available Ni-containing Calcium Hydroxyapatite (NiCaHAp; 3.31 wt.% Ni was synthesized by coprecipitation and used as catalyst support. Molybdenum was supported on NiCaHAp by impregnation using ammonium heptamolybdate. The prepared catalysts Mo(x/NiCaHAp (x: 2 to 8 wt % in Mo were characterized by elemental analysis, XRD, FT-IR, N2 adsorption-desorption and TEM-EDX. The catalysts were sulfided in-situ at 673 K under flowing H2S/H2 (15 Vol.% H2S and tested in hydrodesulfurization (HDS of thiophene at 673 K. The main XRD peaks of hydroxyapatite CaHAp phase were observed in all samples and a peak due probably to crystalline MoO3 phase was also identified from the results. However, no crystalline phase of NiO was found for the catalysts, which showed its Ni species were highly dispersed. The sulfided catalysts Mo(x/NiCaHAp presented are active in HDS of thiophene, despite the presence of some large MoO3 crystallites and incomplete sulfidation. This activity may be due to interaction of NiO and MoO3 on CaHAp resulting in the formation of Ni-Mo-S phase under flowing H2S/H2. When the molybdenum content increased the HDS activity increasead slightly, which was caused by the agglomeration of MoO3. The Mo(8/NiCaHAp catalyst is about two times less active for thiophene HDS than the commercial NiMoP/Al2O3.

  10. Effect of Chitosan on the Performance of NiMoP-Supported Catalysts for the Hydrodesulfurization of Dibenzothiophene

    Directory of Open Access Journals (Sweden)

    Guillermina Ríos-Caloch

    2016-01-01

    Full Text Available Chitosan-added NiMoP catalysts supported on alumina and alumina-titania were studied in the hydrodesulfurization (HDS of dibenzothiophene (DBT. The preparation of catalysts containing Mo (12 wt%, Ni (3 wt%, P (1.6 wt%, and chitosan/nickel = 2 (mol ratio was accomplished by sequential pore-filling impregnation varying the order of chitosan integration. Materials were characterized by DRIFTS, TPR, TG-DTA, and XPS techniques. The TG-DTA study showed that the nature of the support influences the degradation of chitosan onto the catalytic materials and also influences the HDS of DBT and the product distribution as well. The series of catalysts supported on alumina presented the most remarkable effect of chitosan, in which the OH and NH groups of the organic molecule interact with acid sites of the support weakening the interaction between alumina and deposited metal phases. In all cases, DBT was converted mainly through direct sulfur removal. The catalysts ChP3/A (alumina support impregnated with chitosan in phosphoric acid solution, prior to NiMoP deposition and ChP4/AT (alumina-titania support impregnated with NiMoP solution, prior to contacting with a solution comprising chitosan and phosphorus exhibited the best performance in HDS reactions and also showed the highest selectivity in biphenyl formation. Presence of carbonaceous residua on the catalyst’s surface, as shown by XPS, could enhance the HDS activity over the ChP4/AT sample.

  11. In situ FT-IR spectroscopy investigations of carbon nanotubes supported Co-Mo catalysts for selective hydrodesulfurization of FCC gasoline

    Institute of Scientific and Technical Information of China (English)

    Jingcheng Zhang; Wenkun Yin; Hongyan Shang; Chenguang Liu

    2008-01-01

    To better understand the nature of carbon nanotubes supported Co-Mo catalysts (Co-Mo/CNTs) for selective hy-drodesulfurization (HDS) of fluid catalytic cracking (FCC) gasoline, studies are carried out using in situ Fourier transform infrared spectroscopy (FT-IR). The catalytic performances of Co-Mo/CNTs catalysts were evaluated with a mixture of cy-clohexane, diisobutylene, cyclohexene, 1-octene (60 : 30 : 5 : 5, volume ratio) and thiophene (0.5%, ratio of total weight) as model compounds to simulate FCC gasoline. The HDS experimental results suggested that the HDS activity and selectivity of Co-Mo/CNTs catalysts were affected by Co/Mo ratio; the optimal Co/Mo atomic ratio is about 0.4, and the optimum reaction temperature is 260 ℃. The in situ FT-IR studies revealed that 1-octene can be completely saturated at 200 ℃. In the FT-IR spectra of diisobutylene, the characteristic absorption peak around 3081 cm-1 for the stretching vibration peak of=C-H bond was still clear at 320℃, indicating that diisobutylene is difficult to be hydrogenated. As for the thiophene, no characteristic absorption peak could be found around 3092 cm-1 and 835 cm-1 when the reaction temperature was raised to 280 ℃, indi-cating that thiophene had been completely hydrodesulfurized. On the basis of FT-IR results, it can be deduced that thiopbene HDS reaction occurred mainly through direct hydrogenolysis route, whereas thiophene HDS and diisobutylene hydrogenation reaction over Co-Mo/CNTs catalysts might occur on two different kinds of active sites.

  12. Advances in HDS catalysts design: relation between catalyst structure and feed composition

    NARCIS (Netherlands)

    Kagami, Narinobu

    2006-01-01

    The aim of this work is to propose a better understanding of ultra deep HDS for diesel, to contribute to the development of advanced catalysts. The characterization of catalyst structure was examined by XRD, TPR, TPS and Raman spectroscopy. The ranking of catalytic activities were tested using vario

  13. Synthesis,characterization and hydrodesulfurization activity of silica-dispersed NiMoW trimetallic catalysts

    Institute of Scientific and Technical Information of China (English)

    Di Liu; Lihua Liu; Guangci Li; Chenguang Liu

    2010-01-01

    Silica-dispersed NiMoW trimetallic hydrodesulfurization catalysts were prepared by deposition-precipitation method.For comparative purposes,bulk NiMoW trimetallic catalysts were obtained by co-precipitation.Silica was employed to disperse active metals for full utilization of active components and silica-dispersed NiMoW catalyst had high active metal content.BET analysis showed that silica-dispersed NiMoW trimetallic catalysts had a high surface area(165.1 m2/g)and pore volume(0.27 ml/g).Transmission electron microscopy results proved that active components were well dispersed.Hydrodesulfurization activity of silica-dispersed NiMoW catalysts was much higher than that of comparative catalysts and up to twice greater than those of commercial NiMo alumina-supported systems per gram of catalyst.

  14. The Hypertension in Diabetes Study (HDS): a catalyst for change.

    Science.gov (United States)

    Williams, B

    2008-08-01

    Hypertension is now established as a major risk factor for premature cardiovascular morbidity and mortality in people with Type 2 diabetes and all modern treatment guidelines recommend the routine treatment of hypertension in these patients. However, these developments have been relatively recent. Only a decade ago, outside of small studies in patients with nephropathy, there was little evidence with regard to the efficacy and safety of treating elevated blood pressure in people with Type 2 diabetes. Consequently, for many patients, elevated blood pressure remained undetected and untreated. This changed with the publication of the Hypertension in Diabetes Study (HDS) in 1998. This study revealed that hypertension was very common in people with Type 2 diabetes and demonstrated the dramatic benefits of blood pressure lowering in reducing their risk of major macrovascular and microvascular complications. The unequivocal evidence from this study provided a much-needed catalyst for change, propelling blood pressure measurement and its treatment to the forefront of risk management in these patients. Many studies have followed and many questions remain with regard to the preferred anti-hypertensive treatment strategy and optimal treatment targets for blood pressure. In the meantime, many millions of patients with Type 2 diabetes worldwide have benefited and will continue to benefit from the therapeutic insights gained from the treatment of blood pressure in the 1148 patients enrolled in the Hypertension in Diabetes Study in the UK Prospective Diabetes Study.

  15. NiMo/Al2O3 catalyst containing nano-sized zeolite Y for deep hydrodesulfurization and hydrodenitrogenation of diesel

    Institute of Scientific and Technical Information of China (English)

    Hailiang Yin; Tongna Zhou; Yunqi Liu; Yongming Chai; Chenguang Liu

    2011-01-01

    Two mixed-matrix NiMo/Al2O3 catalysts containing nano- and micro-sized zeolite Y have been prepared to explore the size effect of zeolite Y particle on the hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) activities of fluid catalytic cracking (FCC) diesel.They were characterized by SEM,BET,XRD,H2-TPR,NH3-TPD and HRTEM.The results show that the catalyst containing nano-sized zeolite Y possesses larger average pore diameter,higher pore volume,weaker and lesser acid sites,more easily reducible metal phases,shorter MoS2 slabs and more slab layers than the catalyst containing micro-sized zeolite Y.The catalysts were also evaluated with a high-pressure fixed-bed reactor using real FCC diesel as feed.The results display that the catalyst containing nano-sized zeolite Y bears higher HDS and HDN activities and exhibits higher relative rate constant for the removal of total sulfur or nitrogen than the one containing micro-sized zeolite.

  16. High Active Zn/Mg-Modified Ni–P/Al2O3 Catalysts Derived from ZnMgNiAl Layered Double Hydroxides for Hydrodesulfurization of Dibenzothiophene

    Directory of Open Access Journals (Sweden)

    Feng Li

    2017-07-01

    Full Text Available A series of ZnMgNiAl layered double hydroxides (LDHs containing 20 wt.% Ni and different Zn/Mg molar ratios were prepared by a coprecipitation method, and then were introduced with H2PO4− via a microwave-hydrothermal method. With the resulting mixtures as the precursors, Zn/Mg-modified ZnMgNi–P/Al2O3 catalysts were prepared. The Zn/Mg molar ratio affected the formation of Ni2P and Ni12P5 in nickel phosphides. The ZnMgNi–P/Al2O3 catalyst with a Zn/Mg molar ratio of 3:1 exhibits the best dibenzothiophene hydrodesulfurization (HDS activity. Compared with the Ni–P/Al2O3 catalyst prepared from the impregnation method, the ZnMgNi–P/Al2O3 catalyst shows a higher HDS activity (81.6% vs. 54.3% and promotes the direct desulfurization of dibenzothiophene.

  17. The effect of Co-promotion on MoS2 catalysts for hydrodesulfurization of thiophene: A density functional study

    DEFF Research Database (Denmark)

    Moses, Poul Georg; Hinnemann, Berit; Topsøe, Henrik

    2009-01-01

    We present density functional theory (DFT) calculations of the hydrogenation (HYD) and direct desulfurization (DDS) pathways of thiophene hydrodesulfurization (HDS) over cobalt-promoted MoS2. We find that the Co–Mo–S edge in its equilibrium state under HDS conditions is reactive toward both...... to proceed. We find that Co-promotion decreases the barrier of hydrogenation reactions and active site regeneration but increases the barrier of C–S-scission reactions. The net result of Co promotion is found to be an increase in the hydrogenation activity and also of the relative importance of the DDS...

  18. Effect of Mo and Co loading in HDS catalysts supported on solvo-thermally treated ZrO{sub 2}-TiO{sub 2} mixed oxides

    Energy Technology Data Exchange (ETDEWEB)

    Escobar, Jose; Cortes, Maria A. [Instituto Mexicano del Petroleo, Prog. de Ing. Molecular, Eje Central Lazaro Cardenas 152, Col. San Bartolo Atepehuacan, Gustavo A. Madero, Mexico, D.F. 07730 (Mexico); Barrera, Maria C. [Instituto Mexicano del Petroleo, Prog. de Ing. Molecular, Eje Central Lazaro Cardenas 152, Col. San Bartolo Atepehuacan, Gustavo A. Madero, Mexico, D.F. 07730 (Mexico); Universidad Autonoma Metropolitana-Iztapalapa, San Rafael Atlixco 186, Col. Vicentina, Iztapalapa, Mexico, D.F. 09340 (Mexico); Reyes, Jose A. De Los [Universidad Autonoma Metropolitana-Iztapalapa, San Rafael Atlixco 186, Col. Vicentina, Iztapalapa, Mexico, D.F. 09340 (Mexico); Santes, Victor [CIIEMAD-IPN, Calle 30 de Junio de 1520, Col. Barrio la Laguna Ticoman, Gustavo A. Madero, Mexico, D.F. 07340 (Mexico); Gomez, Elizabeth [Instituto de Quimica-UNAM, Circuito Exterior, Ciudad Universitaria, Mexico, D.F. 04510 (Mexico); Pacheco, Jose G. [Division Academica de Ciencias Basicas, Universidad Juarez Autonoma de Tabasco, Km. 1, Carretera Cunduacan-Jalpa de Mendez, Cunduacan, Tabasco (Mexico)

    2008-04-15

    Molybdenum (at 2.8, 3.3, 4.0 and 4.7 atoms nm{sup -2}) and cobalt (Co/(Co + Mo) ratios of 0.3, 0.4 and 0.5) were impregnated on wide-pore ZrO{sub 2}-TiO{sub 2} mixed oxides (30-70) prepared with solvo-thermal treatment (80 C, 1 day). Materials characterization comprised N{sub 2} physisorption, XRD, thermal analyses, and UV-vis DRS, Raman, and IR spectroscopies. For impregnated dried materials (non-calcined) at concentrations beyond 3.3 atom nm{sup -2} and activated by sulfiding (H{sub 2}S/H{sub 2}, 400 C) no further improvement in activity in dibenzothiophene (DBT) hydrodesulfurization (HDS) (at 5.59 MPa, T = 320 C) was observed. Thus, monolayer Mo dispersion was assumed at that content. The aforementioned formulation was chosen to be promoted by Co at different concentrations, the maximum HDS activity being found for sulfided catalyst with Co/(Co + Mo) = 0.4. Nevertheless, the promotion observed by Co addition was small (by a factor of {proportional_to}3.2). The activity trends observed in the DBT HDS were well confirmed in the hydrotreatment of a real feedstock (straight-run gasoil). Dibenzothiophene reliably represented the behavior of organo-sulfur compounds present in the middle distillate, at the reaction conditions used in this study where sterically hindered compounds remained unreacted in the hydrotreated gasoil. (author)

  19. Hydrodesulfurization on Transition Metal Catalysts: Elementary Steps of C-S Bond Activation and Consequences of Bifunctional Synergies

    Science.gov (United States)

    Yik, Edwin Shyn-Lo

    The presence of heteroatoms (e.g. S, N) in crude oil poses formidable challenges in petroleum refining processes as a result of their irreversible binding on catalytically active sites at industrially relevant conditions. With increasing pressures from legislation that continues to lower the permissible levels of sulfur content in fuels, hydrodesulfurization (HDS), the aptly named reaction for removing heteroatoms from organosulfur compounds, has become an essential feedstock pretreatment step to remove deleterious species from affecting downstream processing. Extensive research in the area has identified the paradigm catalysts for desulfurization; MoSx or WSx, promoted with Co or Ni metal; however, despite the vast library of both empirical and fundamental studies, a clear understanding of site requirements, the elementary steps of C-S hydrogenolysis, and the properties that govern HDS reactivity and selectivity have been elusive. While such a lack of rigorous assessments has not prevented technological advancements in the field of HDS catalysis, fundamental interpretations can inform rational catalyst and process design, particularly in light of new requirements for "deep" desulfurization and in the absence of significant hydrotreatment catalyst developments in recent decades. We report HDS rates of thiophene, which belongs to a class of compounds that are most resistant to sulfur removal (i.e. substituted alkyldibenzothiophenes), over a range of industrially relevant temperatures and pressures, measured at differential conditions and therefore revealing their true kinetic origins. These rates, normalized by the number of exposed metal atoms, on various SiO 2-supported, monometallic transition metals (Re, Ru, Pt), range several orders of magnitude. Under relevant HDS conditions, Pt and Ru catalysts form a layer of chemisorbed sulfur on surfaces of a metallic bulk, challenging reports that assume the latter exists as its pyrite sulfide phase during reaction. While

  20. Synthesis of Ni-Mo-W sulfide nanorods as catalyst for hydrodesulfurization of dibenzothiophene.

    Science.gov (United States)

    Paraguay-Delgado, F; García-Alamilla, R; Lumbreras, J A; Cizniega, E; Alonso-Núñez, G

    2008-12-01

    Two trimetallic sulfurs, MoWNiS and MoWSNi, were synthesized to be used as a catalyst in hydrodesulfurization reactions. The mixed oxide mesoporous nanostructured MoO3 -WO3 with an Mo:W atomic ratio of 1:1 was used as the precursor. The first catalyst was prepared by impregnating nickel in the oxide precursor and then subsequent sulfiding with an H2S/H2 mix at 400 degrees C for 2 hours. The second catalyst was prepared by sulfiding the precursor and then impregnating the nickel, and finally reducing the material with a H2/N2 at 350 degrees C. In both catalysts the Mo:W:Ni atomic ratio was maintained at 1:1:0.5. The materials obtained were characterized by physical adsorption of nitrogen, X-ray diffraction, scanning electron microscopy, transmission electron microscopy. Furthermore, the materials obtained were evaluated by a dibenzothiophene hydrodesulfuration reaction. The diffraction patterns show that both materials are polycrystalline and mainly of MoS2 and WS2 phases.

  1. Hydrodesulfurization and hydrodenitrogenation catalysts obtained from coal mineral matter

    Science.gov (United States)

    Liu, Kindtoken H. D.; Hamrin, Jr., Charles E.

    1982-01-01

    A hydrotreating catalyst is prepared from coal mineral matter obtained by low temperature ashing coals of relatively low bassanite content by the steps of: (a) depositing on the low temperature ash 0.25-3 grams of an iron or nickel salt in water per gram of ash and drying a resulting slurry; (b) crushing and sizing a resulting solid; and (c) heating the thus-sized solid powder in hydrogen.

  2. Comportamiento de Catalizadores PtMo/g-Al2O3-B2O3 en Reacciones de Hidrodesaromatización de Naftaleno e Hidrodesulfuración de Dibenzotiofeno Behavior of PtMo/g-Al2O3-B2O3 Catalysts in Naphthalene Hydrodearomatization and Dibenzothiophene Hydrodesulfurization Reactions

    Directory of Open Access Journals (Sweden)

    Víctor G Baldovino-Medrano

    2009-01-01

    Full Text Available Con el propósito de estudiar la funcionalidades de catalizadores de hidrodesulfuración (HDS, se prepararon catalizadores PtMo/g-Al2O3-B2O3, con diferentes concentraciones de Mo y B, y se ensayaron en reacciones de hidrodesaromatización (HDA de naftaleno en presencia de H2S, y HDS de dibenzotiofeno (DBT. Se observó que bajo las condiciones típicas del proceso de hidrotratamiento los catalizadores presentan un bajo desempeño en HDA y alta selectividad hacia la ruta de desulfurización directa en la reacción de HDS de DBT. El análisis del comportamiento catalítico del sistema PtMo en ambas reacciones es consistente con la hipótesis de la existencia de fases activas separadas de Pt y MoS2, donde el Pt cumple una doble función: como centro activo y como promotor de la fase MoS2.With the aim of studying the functionalities of hydrodesulfurization (HDS catalysts, a series of PtMo/g-Al2O3-B2O3 catalysts wit different concentrations of Mo and B were prepared and tested in naphthalene hidrodesaromatization HDA, under H2S atmosphere, and dibenzothiophene (DBT hydrodesulfurization reactions. It was observed that under the typical conditions of hydrotreatment processes, these catalysts present a poor HDA performance, as well as they display a high selectivity to the direct desulfurization reaction route of DBT hydrodesulfurization. An analysis of the catalytic behavior of the PtMo system in both reactions agrees well with the hypothesis of the existence of independent Pt and MoS2 active phases, where Pt is considered to act as both promoter and as an active center.

  3. Comparison of P-containing {gamma}-Al{sub 2}O{sub 3} supported Ni-Mo bimetallic carbide, nitride and sulfide catalysts for HDN and HDS of gas oils derived from Athabasca bitumen

    Energy Technology Data Exchange (ETDEWEB)

    Sundaramurthy, V.; Dalai, A.K. [Catalysis and Chemical Reaction Engineering Laboratories, Department of Chemical Engineering, University of Saskatchewan, Saskatoon, SK (Canada); Adjaye, J. [Syncrude Edmonton Research Centre, Edmonton, AB (Canada)

    2006-09-01

    Phosphorus containing {gamma}-Al{sub 2}O{sub 3} supported bimetallic Ni-Mo carbide, nitride and sulfide catalysts have been synthesized from an oxide precursor containing 12.73wt.% Mo, 2.54wt.% Ni and 2.38wt.% P and characterized by elemental analysis, pulsed CO chemisorption, surface area measurements, X-ray diffraction, temperature-programmed reduction and DRIFT spectroscopy of CO adsorption. DRIFT spectroscopy of adsorbed CO on activated catalysts showed that carbide and nitride catalysts have surface exposed sites of Mo{sup o+} (0hydrodesulfurization (HDS) activities of the bimetallic Ni-Mo carbide, nitride and sulfide catalysts were compared against commercial Ni-Mo/Al{sub 2}O{sub 3} catalyst in a trickle bed reactor using light gas oil and heavy gas oil derived from Athabasca bitumen in the temperature range 340-370 and 375-400{sup o}C respectively at 8.8MPa. The gradual transformation of Ni-Mo carbide and nitride phases into Ni-Mo sulfide phases was observed during precoking period, and the formed Ni-Mo sulfide phases enhanced the HDN and HDS activities of carbide and nitride catalysts. The {gamma}-Al{sub 2}O{sub 3} supported Ni-Mo bimetallic sulfide catalyst was found to be more active for HDN and HDS of light gas oil and heavy gas oil than the corresponding carbide and nitride catalysts on the basis of unit weight. (author)

  4. Characterization and Hydrodesulfurization Properties of Catalysts Derived from Amorphous Metal-boron Materials

    Energy Technology Data Exchange (ETDEWEB)

    Parks, Greg; Pease, Melissa; Layman, Kathryn A.; Burns, Autumn W.; Bussell, Mark E.; Wang, Xianqin; Hanson, Jonathan; Rodriguez, Jose A.

    2007-01-22

    Unsupported and silica-supported amorphous metal-boron materials (Ni-B, Mo-O-B, and Ni-Mo-O-B) were prepared by NaBH4 reduction of aqueous or impregnated metal salts. The resulting materials were characterized by a range of techniques, including conventional and time-resolved X-ray diffraction. The latter technique was used to determine the onset of crystallization of the amorphous materials during annealing in He flow and to identify the phases formed. Annealing of unsupported Ni-B resulted in the crystallization of predominantly Ni3B, followed by Ni metal, whereas Ni-B/SiO2 formed Ni and then NiO. There was no evidence for crystallization of B-containing phases for Mo-O-B or Mo-O-B/SiO2 on annealing; instead, the predominant phase formed was MoO2. In general, the phases formed for Ni-Mo-O-B and Ni-Mo-O-B/SiO2 were consistent with those formed in the monometallic materials, but at higher annealing temperatures. Catalysts prepared by sulfiding Ni-B/SiO2 and Ni-Mo-O-B/SiO2 materials had significantly higher thiophene HDS activities than conventionally prepared sulfided Ni/SiO2 and Ni-Mo/SiO2 catalysts, whereas a sulfided Mo-O-B/SiO2 catalyst had a dramatically lower HDS activity than a sulfided Mo/SiO2 catalyst.

  5. Organometallic Modeling of the Hydrodesulfurization (HDS) Process: Rhenium Carbonyl-promoted C-S Bond Cleavage and Hydrogenation of Thiophenes and Benozothiophenes

    Energy Technology Data Exchange (ETDEWEB)

    Reynolds, Michael A. [Iowa State Univ., Ames, IA (United States)

    2000-09-21

    Organometallic modeling of the HDS process at single or multiple metal centers is one approach to better understanding the mechanism that govern commercial HDS. Therefore, we have currently been investigating the use of Re2(CO)10 as a potential model system for catalytic HDS with respect to S-binding, ring-opening, and hydrogenation of thiophenes andbenzothiophenes. We have also been investigating the use of UV-light as a method for activating thiophenic molecules towards C-S and C-H bond cleavage.

  6. Catalytic activities of Co(Ni)Mo/TiO{sub 2}-Al{sub 2}O{sub 3} catalysts in gasoil and thiophene HDS and pyridine HDN: effect of the TiO{sub 2}-Al{sub 2}O{sub 3} composition

    Energy Technology Data Exchange (ETDEWEB)

    Borque, M.P.; Lopez-Agudo, A. [Instituto de Catalisis y Petroleoquimica, CSIC, Cantoblanco, 28049 Madrid (Spain); Olguin, E.; Vrinat, M. [Institut de Recherches sur la Catalyse, 2 avenue Albert Einstein, 69626 Villeurbanne Cedex (France); Cedeno, L.; Ramirez, J. [Unicat, Facultad de Quimica UNAM, Cd. Universitaria, 04510 Mexico DF (Mexico)

    1999-04-19

    The effect of the TiO{sub 2}-Al{sub 2}O{sub 3} mixed oxide support composition on the hydrodesulfurization (HDS) of gasoil and the simultaneous HDS and hydrodenitrogenation (HDN) of gasoil+pyridine was studied over two series of CoMo and NiMo catalysts. The intrinsic activities for gasoil HDS and pyridine HDN were significantly increased by increasing the amount of TiO{sub 2} into the support, and particularly over rich- and pure-TiO{sub 2}-based catalysts. It is suggested that the increase in activity be due to an improvement in reducing and sulfiding of molybdena over TiO{sub 2}. The inhibiting effect of pyridine on gasoil HDS was found to be similar for all the catalysts, i.e., was independent of the support composition. The ranking of the catalysts for the gasoil HDS test differed from that obtained for the thiophene test at different hydrogen pressures. In the case of gasoil HDS, the activity increases with TiO{sub 2} content and large differences are observed between the catalysts supported on pure Al{sub 2}O{sub 3} and pure TiO{sub 2}. In contrast, in the case of the thiophene test, the pure Al{sub 2}O{sub 3}-based catalyst appeared relatively more active than the catalysts supported on mixed oxides. Also, in the thiophene test the difference in intrinsic activity between the pure Al{sub 2}O{sub 3}-based catalyst appeared relatively more active than the catalysts supported on mixed oxides. Also in the thiophene test, the difference in intrinsic activity between the pure Al{sub 2}O{sub 3}- and pure TiO{sub 2}-based catalysts is relatively small and dependent on the H{sub 2} pressure used. Such differences in activity trend among the gasoil and the thiophene tests are due to a different sensitivity of the catalysts (by different support or promoter) to the experimental conditions used. The results of the effect of the H{sub 2} partial pressure on the thiophene HDS, and on the effect of H{sub 2}S concentration on gasoil HDS demonstrate the importance of these

  7. Characterization and Hydrodesulfurization Properties of Catalysts Derived from Amorphous Metal-Boron Materials

    Energy Technology Data Exchange (ETDEWEB)

    Parks,G.; Pease, M.; Burns, A.; Layman, K.; Bussell, M.; Wang, X.; Hanson, J.; Rodriquez, J.

    2007-01-01

    Unsupported and silica-supported amorphous metal-boron materials (Ni-B, Mo-O-B, and Ni-Mo-O-B) were prepared by NaBH{sub 4} reduction of aqueous or impregnated metal salts. The resulting materials were characterized by a range of techniques, including conventional and time-resolved X-ray diffraction. The latter technique was used to determine the onset of crystallization of the amorphous materials during annealing in He flow and to identify the phases formed. Annealing of unsupported Ni-B resulted in the crystallization of predominantly Ni{sub 3}B, followed by Ni metal, whereas Ni-B/SiO{sub 2} formed Ni and then NiO. There was no evidence for crystallization of B-containing phases for Mo-O-B or Mo-O-B/SiO{sub 2} on annealing; instead, the predominant phase formed was MoO{sub 2}. In general, the phases formed for Ni-Mo-O-B and Ni-Mo-O-B/SiO2 were consistent with those formed in the monometallic materials, but at higher annealing temperatures. Catalysts prepared by sulfiding Ni-B/SiO{sub 2} and Ni-Mo-O-B/SiO{sub 2} materials had significantly higher thiophene HDS activities than conventionally prepared sulfided Ni/SiO2 and Ni-Mo/SiO{sub 2} catalysts, whereas a sulfided Mo-O-B/SiO{sub 2} catalyst had a dramatically lower HDS activity than a sulfided Mo/SiO{sub 2} catalyst.

  8. Development of FCC Naphtha Hydrodesulfurization and Aromatization Process

    Institute of Scientific and Technical Information of China (English)

    Zhu Huaxing; Zhu Jianhua; Liu Jinlong; Sun Diancheng; Gong Xuhui

    2005-01-01

    This articles refers to the development of the technology for hydrodesulfurization (HDS) and aromatization of FCC naphtha This technology adopts a catalyst with aromatization performance, which does not reduce the octane rating of gasoline in the course of HDS of FCC naphtha. Experimental results have shown that the sulfur removal rate of FCC naphtha could reach over 85%, with the RON of gasoline increased by 0.2-0.6 units, the MON increased by 1.3-1.8 units and the antiknock index of the gasoline increased by around one unit. The total C5+ liquid yield was over 95%. The activity of regenerated catalyst could be restored to be equal to that of fresh one after coke burning on the spent catalyst.

  9. XPS Characterization of Carbon Nanotube Supported CoMo Hydrodesulfurization Catalysts

    Institute of Scientific and Technical Information of China (English)

    SHANG, Hong-Yan(商红岩); LIU, Chen-Guang(刘晨光); ZHAO, Rui-Yu(赵瑞玉); WU, Ming-Bo(吴明铂); WEI, Fei(魏飞)

    2004-01-01

    In this paper, the effect of catalytic support and sulfiding method on the chemical state of supported Co-Mo catalysts is studied by XPS. After sulfidation with in-situ method, the majority of molybdenum in CNT supported CoMo catalyst is transferred to a species with a formal chemical state Mo(Ⅳ) in MoS2 phase, and the rest to Mo(Ⅴ)which consists of Mo coordinated both to O and S, such as MoO2S22- and MoO3S2-. In case of CoMo/γ-Al2O3 catalyst sulfided with in-situ method, a fraction of molybdenum is transferred to formal state Mo(Ⅳ) in the form of MoS2, but there is still a mount of unreduced Mo(Ⅵ) phase which is difficult to be sulfided. In CoMo/CNT catalytic system sulfided with ex-situ method, Mo(Ⅳ) in the form of MoS2 is detected along with a portion of unreduced Mo(Ⅵ) phase, suggesting that not all the Mo phases are reduced and sulfided by ex-situ method. As for CoMo/γ-Al2O3, a portion of molybdenum is sulfided to intermediate reduced state Mo(Ⅴ) which consists of Mo coordinated both to O and S, such as MoO2S22- and MoO3S2-, in addition, there is still a fraction of unreduced Mo(Ⅵ)phase. XPS analyses results suggest that CNT support facilitates the reduction and sulfidation of active species to a large extent, and that alumina support strongly interacts with active species, hereby producing a fraction of phase which resists complete sulfiding. Catalytic measurements of catalysts in the HDS of dibenzothiophene (DBT) show that CoMo/CNT catalysts are of higher HDS activity and selectivity than CoMo/γ-Al2O3 catalyst, which is in good relation with the sulfiding behavior of the corresponding catalyst.

  10. Theoretical Studies in Heterogenous Catalysis: Towards a Rational Design of Novel Catalysts for Hydrodesulfurization and Hydrogen Production

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez,J.A.; Liu, P.

    2008-10-01

    important advantage of the cluster approach is that one can use the whole spectrum of quantum-chemical methods developed for small molecules with relatively minor modifications. On the other hand, the numerical effort involved in cluster calculations increases rather quickly with the size of the cluster. This problem does not exist when using slab models. Due to the explicit incorporation of the periodicity of the crystal lattice through the Bloch theorem, the actual dimension of a slab calculation depends only on the size of the unit cell. In practical terms, the slab approach is mainly useful for investigating the behavior of adsorbates at medium and high coverages. Very large unit cells are required at the limit of low to zero coverage, or when examining the properties and chemical behavior of isolated defect sites in a surface. In these cases, from a computational viewpoint, the cluster approach can be much more cost effective than the slab approach. Slab and cluster calculations can be performed at different levels of sophistication: semi-empirical methods, simple ab initio Hartree-Fock, ab initio post-Hartree-Fock (CI, MP2, etc), and density functional theory. Density-functional (DF) based calculations frequently give adsorption geometries with a high degree of accuracy and predict reliable trends for the energetics of adsorption reactions. This article provides a review of recent theoretical studies that deal with the behavior of novel catalysts used for hydrodesulfurization (HDS) reactions and the production of hydrogen (i.e. catalytic processes employed in the generation of clean fuels). These studies involve a strong coupling of theory and experiment. A significant fraction of the review is focused on the importance of size-effects and correlations between the electronic and chemical properties of catalytic materials. The article begins with a discussion of results for the desulfurization of thiophene on metal carbides and phosphides, systems which have the

  11. From biomass to fuels: hydrotreating of oxygen-containing feeds on a CoMo/Al{sub 2}O{sub 3} hydrodesulfurization catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Viljava, T.-R.

    2001-07-01

    Biomass is a renewable alternative to fossil raw materials in the production of liquid fuels and chemicals. Liquefied biomass contains an abundance of oxygen-containing molecules that need to be removed to improve the stability of the liquids. A hydrotreating process, hydrodeoxygenation (HDO), is used for the purpose. Hydrodeoxygenation is similar to the hydrodesulfurization (HDS) process used in oil refining, relying upon a presulfided CoMo/{gamma}-Al{sub 2}O{sub 2}; catalyst. The stability of the sulfided catalyst is critical in HDO because biocrudes usually do not contain the sulfur compounds needed to maintain the sulfidation of the catalyst. The aim of this work was to examine the role of sulfur in maintaining the activity of the HDO catalyst. Sulfur was introduced as an organic sulfur-containing co-reactant or as a sulfur substituent in an oxygen-containing reactant molecule as a way of simulating mixed feeds composed of biocrudes and conventional crudes, or it was introduced as a low molecular weight sulfiding agent. In addition, the stability of the sulfided catalyst against changes in the feed composition was studied to find out whether the activity of the catalyst could be maintained by carrying out HDO alternately with HDS. Simultaneous HDO and HDS was studied in a batch reactor with model compounds having a sulfur-containing (inercapto or inethylmercapto) and an oxygen-containing (hydroxyl or inethoxy) substituent in the same molecule, and with binary mixtures of mono-substituted benzene compounds. In both cases, the reactions of the oxygencontaining substituents were strongly suppressed as long as a sulfur-containing functionality was present. HDS reactions of inercapto and inethylinercapto groups were either enhanced or retarded in the presence of oxygen-containing functionality. HDS was enhanced when the oxygen-containing substituent was located in Para-position to the sulfur substituent thereby increasing the electronegativity of the sulfur atom and

  12. Developing Enzyme and Biomimetic Catalysts for Upgrading Heavy Crudes via Biological Hydrogenation and Hydrodesulfurization

    Energy Technology Data Exchange (ETDEWEB)

    Borole, A P

    2006-08-22

    The recovery and conversion of heavy oils is limited due to the high viscosity of these crudes and their high heteroatom content. Conventional technology relies on thermochemical hydrogenation and hydrodesulfurization to address these problems and is energy intensive due to the high operating temperature and pressure. This project was initiated to explore biological catalysts for adding hydrogen to the heavy oil molecules. Biological enzymes are efficient at hydrogen splitting at very mild conditions such as room temperature and pressure, however, they are very specific in terms of the substrates they hydrogenate. The goal of the project was to investigate how the specificity of these enzymes can be altered to develop catalysts for oil upgrading. Three approaches were used. First was to perform chemical modification of the enzyme surface to improve binding of other non-natural substrates. Second approach was to expose the deeply buried catalytic active site of the enzyme by removal of protein scaffolding to enable better interaction with other substrates. The third approach was based on molecular biology to develop genetically engineered systems for enabling targeted structural changes in the enzyme. The first approach was found to be limited in success due to the non-specificity of the chemical modification and inability to target the region near the active site or the site of substrate binding. The second approach produced a smaller catalyst capable of catalyzing hydrogen splitting, however, further experimentation is needed to address reproducibility and stability issues. The third approach which targeted cloning of hydrogenase in alternate hosts demonstrated progress, although further work is necessary to complete the cloning process. The complex nature of the hydrogenase enzyme structure-function relationship and role of various ligands in the protein require significant more research to better understand the enzyme and to enable success in strategies in

  13. Intensification of Deep Hydrodesulfurization Through a Two-stage Combination of Monolith and Trickle Bed Reactors

    Institute of Scientific and Technical Information of China (English)

    Min Xu; Hui Liu⁎; Shengfu Ji; Chengyue Li

    2014-01-01

    Deep hydrodesulfurization (HDS) is an important process to produce high quality liquid fuels with ultra-low sul-fur. Process intensification for deep HDS could be implemented by developing new active catalysts and/or new types of reactors. In this work, the kinetics of dibenzothiophene (DBT) hydrodesulfurization over Ni-P/SBA-15/cordierite catalyst was investigated at 340-380 °C and 3.0-5.0 MPa. The first-order reaction model with respect to both DBT and H2 was used to fit the kinetics data in a batch recycle operation system. It is found that both the activation energy and rate constant over the Ni-P monolithic catalyst under our operating conditions are close to those over conventionally used HDS catalysts. Comparative performance studies of two types of reactors, i.e., trickle bed reactor and monolithic reactor, were performed based on reactor modeling and simulation. The results indicate that the productivity of the monolithic reactor is 3 times higher than that of the trickle bed reactor on a catalyst weight basis since effective utilization of the catalyst is higher in the monolithic reactor, but the volumetric productivity of the monolithic reactor is lower for HDS of DBT. Based on simulation results, a two-reactor-in-series configuration for hydrodesulfurization is proposed, in which a monolithic reactor is followed by a tickled bed reactor so as to attain intensified performance of the system converting fuel oil of different sulfur-containing compounds. It is il ustrated that the two reactor scheme outperforms the trickle bed reactor both on reactor volume and catalyst mass bases while the content of sulfur is reduced from 200μg·g-1 to about 10μg·g-1.

  14. HDS, HDN and HDA activities of nickel-molybdenum catalysts supported on alumina

    Energy Technology Data Exchange (ETDEWEB)

    Dominguez-Crespo, M.A. [Instituto Mexicano del Petroleo, Programa de Tratamiento de Crudo Maya. Avenida Eje Central Lazaro Cardenas No.152, Col. San Bartolo Atepehuacan, 07730, Mexico D. F. (Mexico); Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada (CICATA-Altamira, IPN) Km 14.5 Carretera Tampico-puerto Industrial 89600, Altamira, Tamaulipas (Mexico); Torres-Huerta, A.M.; Ramirez-Meneses, E. [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada (CICATA-Altamira, IPN) Km 14.5 Carretera Tampico-puerto Industrial 89600, Altamira, Tamaulipas (Mexico); Diaz-Garcia, L. [Instituto Mexicano del Petroleo, Programa de Tratamiento de Crudo Maya. Avenida Eje Central Lazaro Cardenas No.152, Col. San Bartolo Atepehuacan, 07730, Mexico D. F. (Mexico); Arce-Estrada, E.M. [Instituto Politecnico Nacional, Departamento de Metalurgia y Materiales. A.P. 75-876, 07300 Mexico, D. F. (Mexico)

    2008-08-15

    In this work, NiMo-Al{sub 2}O{sub 3} catalysts were prepared by using different alumina precursors. The supports were impregnated by means of the spray at incipient wetness technique in both basic and acid media. Both the supports and fresh catalysts were characterized by the adsorption-desorption isotherms, Temperature-Programmed Reduction (TPR), Thermal Pyridine Adsorption-Desorption (TPD) and X-Ray Diffraction analyses (XRD). After sulfidation, the NiMoS metallic particles were characterized by Transmission Electron Microscopy (TEM). The initial analyses were performed in a trickle-bed reactor by using a real feedstock (Mexican heavy gas oil) and performing hydrotreating reactions (HDS, HDN and HDA) at three different temperatures: 613, 633 and 653 K; and 54 kg cm{sup -} {sup 2}. The catalytic activities are discussed in relation to the physicochemical properties of the NiMo catalysts, alumina phase and pH of the impregnating solution. The catalytic results show an increase in the conversion profiles with temperature. The sulfur conversion was increased from 89 to 99.25%, 91-99%, 90.8-97%, 83-95% and 78-96% when the crystal size of the support varied from 3 to 20 nm, respectively. The nitrogen and aromatic conversions were also increased in the range of 23-45 wt.%. It was found that the {gamma} phase reached a higher catalytic performance than the {eta} phase. The NiMo catalysts synthesized in a basic medium showed a better catalytic performance than that obtained with those prepared in acid solutions. The significance of the kinetic data to compare the catalysts is discussed. The maximum value of the catalytic activity was reached with the catalysts with the smallest particle sizes. (author)

  15. HDS for fuel cell applications

    NARCIS (Netherlands)

    Alsolami, B.H.

    2012-01-01

    The objective of this chapter is to investigate the feasibility of developing a catalytic hydrodesulfurization (HDS) process operating under low pressure and high temperature conditions to produce a near-zero sulfur content diesel suitable for fuel cell applications. As expected, it was found that d

  16. Preparation, Characterization, Hydrodesulfurization and Hydrodenitrogenation Activities of Alumina-supported Tungsten Phosphide Catalysts%WP/γ-Al2O3催化剂的制备、表征及加氢脱硫和加氢脱氮活性

    Institute of Scientific and Technical Information of China (English)

    李翠清; 孙桂大; 李成岳; 宋亚娟

    2006-01-01

    Two series of WP/Al2O3 catalyst precursors with WP mass loading in the range 18.5%-37.1% were prepared using the impregnation method and mixing method, respectively, and the catalysts were then obtained by temperature-programmed reduction of supported tungsten phosphate (precursor of WP/Al2O3 catatlysts) in H2 at 650℃ for 4h. The catalysts were characterized by XRD, BET, TG/DTA, XPS and 31p MAS-NMR. The activities of these catalysts were tested in the hydrodenitrogenation (HDN) of pyridine and hydrodesulfurization (HDS) of thiophene at 340℃ and 3.0MPa. The results showed that owing to the stronger interaction of the support with the active species, the precursor of WP/Al2O3 catalyst was more difficultly phosphided and a greater amount of W species was in a high valence state W6+ on the surface of the catalyst prepared by the impregnation method than that by the mixing method. 31p MAS-NMR results indicated that 31p shift from 85% H3PO4 of 2.55 × 10-4 for WP and 2.57 × 10-4 for WP/γ-Al2O3 catalysts prepared by mixing method. Such WP/Al2O3 catalysts showed higher HDN activities and lower HDS activities than those prepared by the impregnation method under the same loading of WP.WP/γ-Al2O3 catalysts with weak interaction between support and active species were favorable for HDN reaction while the WP/γ-Al2O3 catalysts with strong interaction were favorable for HDS reaction.

  17. HDS and deep HDS activity of Co/Mo/S-mesostructured synthetic clays.

    Energy Technology Data Exchange (ETDEWEB)

    Carrado, K. A.; Song, C.; Kim, J. H.; Castagnola, N.; Fernandez-Saavedra, R.; Marshall, C. L.; Schwartz, M. M.; Penn State Univ.; ICMM-CSIC

    2006-01-01

    The goal of this work is to identify more promising supports from synthetic clay materials to advance hydrotreating catalyst development. Silica sol can be used as the silicon-containing starting material when creating nanoporous layered silicate catalysts with a certain portion of unreacted sol particles incorporated into the final matrix. The resulting structure then has mesoporosity and a unique morphology. Hectorite-based clays have been prepared using different silica sols in order to ascertain the importance of sol characteristics on the final matrix. Several techniques have been applied to characterize the materials, including XRD, TGA, N2 porosimetry, and TEM. For hydrodesulfurization (HDS), the conversion of dibenzothiophene (DBT) to biphenyl was examined at 400 degrees C using CoMoS-loaded mesostructured clay supports. No hydrogenation or hydrocracking was observed with any of the clay supports. The most active clay was derived from Ludox silica sol AS-30 with an activity of 65% DBT conversion and 100% selectivity to biphenyl (BP). For comparison, a reference commercial catalyst displayed 94% BP selectivity. For deep HDS, the conversion of 4,6-dimethyldibenzothiophene was tested at 325 and 350 degrees C. At 325 degrees C, conversions are 92% of commercial catalysts for a CoMoS-loaded mesostructured clay derived from Ludox AM-30 silica sol. A commercially available synthetic hectorite called laponite has very low activity, indicating that the unique morphology of the mesostructured clays is important. Hydrogenolysis vs. hydrogenation pathways are compared for the deep HDS reaction. HR-TEM of the most active deep HDS catalyst revealed a multilayered MoS2 morphology.

  18. Effects of pH and chelating agent on the NiWS phase formation in NiW/γ-Al{sub 2}O{sub 3} HDS catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Santolalla-Vargas, C.E.; Suárez Toriello, V.A. [Universidad A. Metropolitana-Iztapalapa, Área de Ingeniería Química, Av. FFCC R, Atlixco 186, Vicentina, 09340 Distrito Federal (Mexico); Reyes, J.A. dos, E-mail: jarh@xanum.uam.mx [Universidad A. Metropolitana-Iztapalapa, Área de Ingeniería Química, Av. FFCC R, Atlixco 186, Vicentina, 09340 Distrito Federal (Mexico); Cromwell, D.K. [University of New Hampshire, Department of Chemical Engineering, 207 Thompson Hall, Durham, NH 03824 (United States); Pawelec, B.; Fierro, J.L.G. [Instituto de Catálisis y Petroleoquímica, CSIC, Cantoblanco, E-28049, Madrid (Spain)

    2015-09-15

    In this article, NiW/γ-Al{sub 2}O{sub 3} samples were prepared by consecutive impregnations of a W/γ-Al{sub 2}O{sub 3}-based catalyst with aqueous solution of nickel salt. The structural control of the nickel ion precursor in the impregnation solution was achieved by the addition of 1,2-cyclohexanediamine-N,N,N′,N′-tetraacetic acid (CyDTA) as a chelating agent. The influence of pH of this aqueous solution on the NiWS phase formation in the sulfided catalysts was investigated. Coordination structures of the Ni–CyDTA complexes were evaluated by FT-IR and DRS UV–Vis spectroscopies. Sulfided catalysts were characterized by X-ray photoelectron spectroscopy (XPS) and high resolution transmission electron microscopy (HRTEM) and tested in hydrodesulfurization (HDS) of 4,6-dimethyldibenzothiophene (4,6-DMDBT) carried out in a batch reactor at 593 K and total H{sub 2} pressure of 55 bar. Spectroscopic characterization by DRS UV–Vis showed the predominance of the [Ni(CyDTA)]{sup 2−} species in solution. Following the impregnation and drying steps, the [Ni(CyDTA)]{sup 2−} complex showed no apparent changes of its structure, independent of the pH value of impregnation solution. The Ni/W/γ-Al{sub 2}O{sub 3} catalysts ex [Ni(CyDTA)]{sup 2−} complex exhibited high stability. The presence of CyDTA delayed the reduction of Ni and caused a remarkable decrease of the W-support interaction, thus increasing the formation of NiWS phase upon catalyst sulfiding. The catalyst activity–structure correlation demonstrated that the catalyst activity and selectivity is linked with formation of the most active NiWS phase having single or double WS{sub 2} slab structures. The catalyst prepared with [Ni(CyDTA)]{sup 2−} complex at pH of 4.0 exhibited the largest initial HDS activity, which was approximately triple compared with the CyDTA-free counterpart. For all catalysts, the HDS reaction proceeded via hydrogenation (HYD) and direct desulfurization (DDS) reaction routes

  19. ELUCIDATION OF HYDRODESULFURIZATION AND HYDROGENATION MECHANISMS USING RADIOISOTOPE TRACER METHODS

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    To meet the specification of sulfur and aromatic contents in diesel fuel, it is necessary for refiners to develop a new catalyst with high activity of hydrodesulfurization and hydrogenation. In the present study, the properties of noble metal catalysts for hydrodesulfurization and hydrogenation in the presence of sulfur compounds have been investigated. The hydrogenation activity of phenanthrene (PHE) on single noble metal and double noble metal catalysts—Pt/Al2O3, Pd/Al2O3 and Pd-Pt/Al2O3 in the presence of dibenzothiophene (DBT) was perforrned in a fixed bed flow reactor. The Pt based catalysts revealed the similar HDS activities and higher HYD activity compared with convertional Mo based ca-talysts. The maximum activity was obtained around 320 ℃ for both catalyst types. The Pt based catalysts produced perhydrophenanthrene as a major product at the maximum activity in the hydrogenation of PHE while the Mo based catalysts produced octahydrophenanthrene.   A  35S radioisotope pulse tracer method (35S RPTM) was used to estimate the behavior of sulfur on the working catalysts and to clarity the differences between Pt and Mo based catalysts. Very little amount of labile sulfur was accumulated on the Pt and Pd catalysts in the HDS of [35S]DBT (PtS0.25 or PdS0.25). This indicates that the mechanism of DBT HDS on noble metal catalysts is significantly different from that on conventional Mo based catalysts where Mo is present as MoS2 less than 60% of which can be labile in the case of Co-Mo/Al2O3.   Another Ru-Cs/Al2O3 catalysts were also prepared and the behavior of sulfur on the working catalyst was compared with those of Mo based catalysts and Pt and Pd catalysts. The values of labile sulfur in the HDS reaction for Ru-Cs catalysts approximately correspond to RuS0.5-0.74. These amounts of labile sulfur are much higher than those for Pt and Pd catalysts. The result suggests that the oxidation state of Ru species is present between the oxidation states

  20. 柠檬酸对NiW/γ-Al2O3加氢脱硫催化剂性能的影响%Effect of Citric Acid on the Performance of NiW/γ-Al2O3 Hydrodesulfurization Catalysts

    Institute of Scientific and Technical Information of China (English)

    杨义; 杨成敏; 周勇; 郭蓉

    2012-01-01

    以柠檬酸(CA)为助剂,采用不同浸溃方法制备NiW-CA加氢脱硫催化剂,考察了不同浸渍方法对催化剂性质及其柴油加氢脱硫活性的影响;采用TPR、SEM-EDS、XRD、HRTEM等手段对催化剂进行表征.结果表明,添加柠檬酸助剂能够减弱NiW催化剂中金属组分与载体的相互作用,有利于金属组分在硫化过程中的再分散,增加金属的硫化度和WS2晶粒的堆叠,因而提高催化剂的加氢脱硫活性,活性由大到小的顺序为先浸渍柠檬酸的催化剂CA+M、共浸渍柠檬酸的催化剂CAM、后浸渍柠檬酸的催化剂M+ CA.%NiW-CA catalysts for hydrodesulfurization were prepared by different orders of impregnation with citric acid as additive. The effects of different impregnations on the properties and diesel hydrodesulfurization (HDS) activity of NiW-CA were investigated. The physical and chemical properties of the catalysts were analyzed by using TPR, SEM-EDS, XRD and HRTEM. The results showed that with citric acid as the additive for NiW-CA preparation the interaction between the metal species and support could be weaken, which was benefit for redispersion of metals on the sulfidation step and increase of the metal sulfidation degree and the stack number of WS2 particles, therefore, the HDS activity of NiW-CA catalysts could be enhanced. Among the three NiW-CA catalysts prepared by different orders of impregnation with citric acid, the CA+M prepared by first impregnation with citric acid possessed highest HDS activity, M+CA prepared by second impregnation with citric acid possessed lowest HDS activity, and the HDS activity of CAM prepared by co-impregnation with citric acid was between that of CA+M and M+CA.

  1. XAFS studies on highly dispersed Ni 2P/SiO 2 catalysts for hydrodesulfurization of 4,6-dimethyldibenzothiophene

    Science.gov (United States)

    Cho, Kye-Sung; Lee, Yong-Kul

    2010-09-01

    The Ni 2P catalysts were prepared by a new synthetic method with the use of less oxidic phosphorus precursor in order to achieve high dispersion on silica support, and their structural properties and catalytic activity in HDS of 4,6-DMDBT were studied. Comparison was made with a conventionally prepared sample which was obtained by temperature programmed reduction method. Various characterizations were conducted by BET, CO uptake, TPR, XRD and X-ray absorption spectroscopy. The amounts of CO chemisorption uptake were 64 and 20 μmol g -1 for Ni 2P/SiO 2-LT and Ni 2P/SiO 2-HT, respectively, indicating that the low temperature reduction technique led to better dispersion of Ni 2P particles on SiO 2 support. The catalytic activity in the HDS of 4,6-DMDBT followed the order, Ni 2P/SiO 2-HT(54%)HDS activity of the Ni 2P catalysts highly depend on the dispersion of the Ni 2P phase.

  2. Optimized Combination of Residue Hydrodesulfurization and Residue Fluid Catalytic Cracking

    Institute of Scientific and Technical Information of China (English)

    Chen Junwu

    2003-01-01

    @@1 Introduction Combination of residue hydrodesulfurization (HDS) and resi-due fluid catalytic cracking (RFCC) is a unique technologyfor processing high-sulfur residue. This paper discusses theoptimized combination of these two processes.

  3. SBA-15 Mesoporous Silica as Catalytic Support for Hydrodesulfurization Catalysts—Review

    Directory of Open Access Journals (Sweden)

    Eric M. Rivera-Muñoz

    2013-09-01

    Full Text Available SBA-15 is an interesting mesoporous silica material having highly ordered nanopores and a large surface area, which is widely employed as catalyst supports, absorbents, drug delivery materials, etc. Since it has a lack of functionality, heteroatoms and organic functional groups have been incorporated by direct or post-synthesis methods in order to modify their functionality. The aim of this article is to review the state-of-the-art related to the use of SBA-15-based mesoporous systems as supports for hydrodesulfurization (HDS catalysts.

  4. Simulation of hydrodesulfurization using artificial neural network

    Energy Technology Data Exchange (ETDEWEB)

    Wang, W.; Zhang, Q.; Zheng, Y. [New Brunswick Univ., Fredericton, NB (Canada). Dept. of Chemical Engineering; Ding, L. [National Centre for Upgrading Technology, Devon, AB (Canada)

    2010-10-15

    By 2011, refineries in North America will be required to reduce the sulphur content of diesel fuel to 10 ppm. In this study, an artificial neural network (ANN) was used to simulate the hydrodesulfurization (HDS) process of DBT, 4-MDBT and 4.6-DMDBT with light-cycle oil as feed and NiMo/Al2O3 as catalyst. The Langmuir-Hinshelwood kinetic mechanism was introduced into the ANN model so that it could follow the given reaction mechanisms. Both advantages of self-learning ability of ANN and the existing knowledge of HDS were taken into account. A lengthy training process was minimized by using this approach. The effects of operating temperature, pressure, and LHSV on the sulphur removal rate were investigated. The inhibition of nitrogen compounds was also considered. The study showed that nitrogen components have a negative impact on the activity of sulphur components and can significantly reduce their conversion rate, particularly in the hard sulphur component 4,6-DMDBT. 23 refs., 5 tabs., 9 figs.

  5. Synthesis of MoS(2) nanorods and their catalytic test in the HDS of dibenzothiophene.

    Science.gov (United States)

    Albiter, M A; Huirache-Acuña, R; Paraguay-Delgado, F; Rico, J L; Alonso-Nuñez, G

    2006-07-28

    Partially sulfided nanostructures were synthesized by direct sulfurization of alpha-MoO(3) nanorods using a mixture of H(2)S/H(2), 15 vol%, at several temperatures (400, 500, 600, 700, and 800 degrees C). These materials were tested as catalysts in the hydrodesulfurization (HDS) of dibenzothiophene (DBT) and characterized by specific surface areas using the expression developed by Brunauer, Emmett, and Teller (BET equation), x-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The TEM images show a gradual evolution from a smooth surface to a rough material, presenting some type of holes all over the particles, but keeping their rod-like structure throughout sulfidation. The results of evaluating the catalysts in the HDS of DBT showed that the best temperature for sulfidation is 500 degrees C. In all samples, a higher selectivity for hydrogenation over sulfur removal was observed.

  6. Atomic-scale insight into the origin of pyridine inhibition of MoS2-based hydrotreating catalysts

    DEFF Research Database (Denmark)

    Temel, Burcin; Tuxen, Anders K.; Kibsgaard, Jakob

    2010-01-01

    Basic nitrogen-containing compounds such as pyridine are well known to be inhibitors of the hydrodesulfurization (HDS) reaction for the MoS2-based catalysts. From an interplay of scanning tunneling microscopy (STM) experiments and density functional theory (DFT) calculations, atomic-scale insight...

  7. Relation between Hydrogen Evolution and Hydrodesulfurization Catalysis

    DEFF Research Database (Denmark)

    Šaric, Manuel; Moses, Poul Georg; Rossmeisl, Jan

    2016-01-01

    A relation between hydrogen evolution and hydrodesulfurization catalysis was found by density functional theory calculations. The hydrogen evolution reaction and the hydrogenation reaction in hydrodesulfurization share hydrogen as a surface intermediate and, thus, have a common elementary step......, which indicates that the same catalyst should perform well for both hydrogen evolution and hydrogenation. If that catalyst also fulfills additional criteria for breaking carbon–sulfur bonds and releasing hydrogen sulfide, it will be a good hydrodesulfurization catalyst. The hydrogen evolution reaction...... is normally performed at room temperature and standard pressure, whereas the hydrodesulfurization reaction is driven by high temperature and pressure. Owing to the very different operating conditions, the adsorption free energy of hydrogen differs between hydrodesulfurization and the hydrogen evolution...

  8. Selective recovery of molybdenum from spent HDS catalyst using oxidative soda ash leach/carbon adsorption method.

    Science.gov (United States)

    Park, Kyung Ho; Mohapatra, D; Reddy, B Ramachandra

    2006-11-16

    The petroleum refining industry makes extensive use of hydroprocessing catalysts. These catalysts contain environmentally critical and economically valuable metals such as Mo, V, Ni and Co. In the present study, a simple hydrometallurgical processing of spent hydrodesulphurization (HDS) catalyst for the recovery of molybdenum using sodium carbonate and hydrogen peroxide mixture was investigated. Recovery of molybdenum was largely dependent on the concentrations of Na2CO3 and H2O2 in the reaction medium, which in turn controls the pH of leach liquor and the presence of Al and Ni as impurities. Under the optimum leaching conditions (40 g L(-1) Na2CO3, 6 vol.% H2O2, room temperature, 1h) about 85% recovery of Mo was achieved. The leach liquor was processed by the carbon adsorption method, which selectively adsorbs Mo at pH around 0.75. Desorption of Mo was selective at 15 vol.% NH4OH. With a single stage contact, it was found possible to achieve >99%, adsorption and desorption efficiency. Using this method, recovery of molybdenum as MoO3 product of 99.4% purity was achieved.

  9. Effect of Particle Size on the HDS Activity of Molybdenum Sulfide

    Directory of Open Access Journals (Sweden)

    Carola Contreras

    2016-01-01

    Full Text Available More than half of the total world oil reserves are heavy oil, extra heavy oil, and bitumen; however their catalytic conversion to more valuable products is challenging. The use of submicronic particles or nanoparticles of catalysts suspended in the feedstock may be a viable alternative to the conversion of heavy oils at refinery level or downhole (in situ upgrading. In the present work, molybdenum sulfide (MoS2 particles with varying diameters (10000–10 nm were prepared using polyvinylpyrrolidone as capping agent. The prepared particles were characterized by DLS, TEM, XRD, and XPS and tested in the hydrodesulfurization (HDS of a vacuum gas oil (VGO. A correlation between particle size and activity is presented. It was found that particles with diameters around 13 nm show double the HDS activity compared with the material with micrometric particle sizes (diameter ≈ 10,000 nm.

  10. A new material for selective removal of nitrogen compounds from gasoils towards more efficient HDS processes.

    Science.gov (United States)

    Macaud, Mathieu; Schulz, Emmanuelle; Vrinat, Michel; Lemaire, Marc

    2002-10-21

    A selective removal of nitrogen compounds from gasoils is proposed, using a recyclable sorbent capable of forming charge-transfer complexes; the selective elimination of nitrogen compounds strongly improves the hydrodesulfurization (HDS) of denitrogenated feed.

  11. The Pore Confinement Effect of FDU-12 Mesochannels on MoS2 Active Phases and Their Hydrodesulfurization Performance

    Directory of Open Access Journals (Sweden)

    Cong Liu

    2016-01-01

    Full Text Available FDU-12 silica with highly ordered face-centered cubic mesoporous structure is developed as support to prepare Mo/FDU-12 catalysts for hydrodesulfurization (HDS of dibenzothiophene (DBT. A series of Mo/FDU-12 catalysts are synthesized by using incipient wetness impregnation method with different MoO3 loadings (6, 8, 10, 12, and 15 wt.%. The objective of this work is to explore the pore confinement effect of FDU-12 mesochannels on the MoS2 morphology with various metal loadings. It is found that, as increasing MoO3 loadings from 6 to 15 wt.%, the MoS2 nanocrystallites transform from monolayer to multilayer and the morphology changes from straight layered to curved and then to ring-like and finally to spherical-like morphology due to the restriction of cage-like pore channels of FDU-12 support. The HDS results show that the catalytic activity increases first and then decreases with the best HDS performance at the MoO3 loading of 10 wt.%. In addition, we compared the HDS activity of Mo catalyst supported on FDU-12 with that on the commercial γ-Al2O3 and SBA-15; the result exhibits that FDU-12 is superior to the other two supports due to its large pore size and ordered three-dimensional open pore channels.

  12. 氮化物对柴油加氢脱硫影响的研究进展%Study on Impacts of Nitrogen Compouds on Diesel Hydrodesulfurization

    Institute of Scientific and Technical Information of China (English)

    刘洪海; 刘继华; 宋永一; 白天忠; 王坤

    2012-01-01

    分别从催化剂,工艺条件等方面介绍了氮化物对柴油加氢脱硫反应(HDS)影响的机理。介绍了氮化物对柴油HDS反应影响的动力学研究。结果表明:氮化物对柴油HDS反应具有抑制作用;在不同催化剂活性中心上和不同的工艺条件下氮化物对柴油HDS反应的影响存在差异且符合于拟一级反应动力学。氮化物对柴油HDS的影响研究,可以指导高活性催化剂的开发,寻求最优柴油HDS反应工艺。%The mechanisms of the hydrodesulfurization(HDS) paths are specifically studied from catalysts;industry conditions etc.The kinetics of the effect of nitrogen compounds on HDS is deeply investigated.The results showed that the HDN routes are similar to the HDS paths,so the HDS of diesel fuel was inhibited by the nitrogen compounds;The nitrogen compounds had competing adsorption with the sulfur compounds on the active sites of different catalysts;The effects of nitrogen compounds on the HDS of diesel fuel existed diversities from different the industry conditions;The impacts of nitrogen compounds on the HDS of diesel fuel were accorded with the pseudo-first-order rate equation.The study on the effects of nitrogen compounds on diesel HDS could guide the development of the high-activity catalysts,and the seeking of the optimal processing conditions for the HDS of diesel fuel.

  13. Morphology tuning of CoMo catalysts: Effect of La and Fe as an additive

    Directory of Open Access Journals (Sweden)

    Yu Pei

    2016-01-01

    Full Text Available Three catalysts CoMo/γ-Al2O3, CoMo-La/γ-Al2O3, CoMo-Fe/γ-Al2O3 with different morphologies were prepared for study the effect of introduction of La and Fe on morphology properties and hydrodesulfurization (HDS activity. The morphology properties of catalysts were characterized by BET, XPS and HRTEM. In addition, the catalytic performances of catalysts were investigated. The results indicated that the introduction of La and Fe promoted the sulfidation of Mo species and made the average length and stacking layer numbers of MoS2 slabs longer and higher. These effects could improve the activity of catalysts for HDS. The present results indicated that the catalyst modified by Fe had the best HDS activity with the optimal morphology among three catalysts

  14. Monometallic Pd and Pt and Bimetallic Pd-Pt/Al2O3-TiO2 for the HDS of DBT: Effect of the Pd and Pt Incorporation Method

    Directory of Open Access Journals (Sweden)

    Reynaldo Martínez Guerrero

    2014-01-01

    Full Text Available The effect of the preparation method of monometallic Pd and Pt and bimetallic Pd-Pt/Al2O3-TiO2 catalysts on the hydrodesulfurization (HDS of dibenzothiophene (DBT was investigated in this study. The synthesis was accomplished using three methods: (A impregnation, (B metal organic chemical vapor deposition (MOCVD, and (C impregnation-MOCVD. The bimetallic Pd-Pt catalyst prepared by the impregnation-MOCVD method was most active for the HDS of DBT compared to those prepared by the single impregnation or MOCVD method due to the synergetic effect between both noble metals. The greater selectivity toward biphenyl indicated that this bimetallic Pd-Pt catalyst preferentially removes sulfur via the direct desulfurization mechanism. However, the bimetallic Pd-Pt catalyst prepared using the single MOCVD method did not produce any cyclohexylbenzene, which is most likely associated with the hydrogenation/dehydrogenation sites.

  15. Molecular metal sulfide cluster model for substrate binding to oil-refinery hydrodesulfurization catalysts.

    Science.gov (United States)

    Herbst, Konrad; Monari, Magda; Brorson, Michael

    2002-03-25

    Reaction between [(eta5-Cp')3Mo3S4]+ and [Ni(1,5-cod)2] (Cp' = methylcyclopentadienyl; 1,5-cod = 1,5-cyclooctadiene) in THF at ambient temperature yielded a coordinatively unsaturated cubane-like cluster cation, [(eta5-Cp')3Mo3S4Ni]+. The ligand sphere at the Ni atom could be saturated by coordinating dimethyl sulfide, diethyl sulfide, di(tert-butyl) sulfide, tetrahydrothiophene, thiochroman-4-ol, 1,4-dithiane, pyridine, quinoline, or 4,4'-bipyridine. The products structurally model a mode of substrate coordination on proposed binding sites of heterogeneous MoNi sulfide hydrotreating catalysts. No stable coordination compounds could be isolated for thiophene derivatives. X-ray crystal structures are reported for the ligand-bridged dicluster compounds [[(eta5-Cp')3Mo3S4Ni]2(mu-C4H4S2)][pts]2 (C4H8S2 = 1,4-dithiane) and [[(eta5-Cp')3Mo3S4Ni]2(mu-bipy)][pts]2 (bipy = 4,4'-bipyridine).

  16. RS-1100柴油加氢脱硫催化剂的研制%THE DEVELOPMENT OF RS-1100 DIESEL HYDRODESULFURIZATION CATALYST

    Institute of Scientific and Technical Information of China (English)

    王锦业; 丁石; 李会峰; 王哲

    2012-01-01

    采用合适的拟薄水铝石制备氧化铝载体,并以浸渍法制备NiMo/Al2O3催化剂,找到催化剂中适宜的Ni/(Ni+ Mo)原子比,在浸渍液中引入适量的助剂和有机络合剂可以提高NiMo/Al2O3催化剂的活性.采用拉曼光谱和紫外-可见光谱仪对浸渍液进行表征,结果表明:浸渍液中存在杂多酸阴离子[P2 Mo5 O23]6-;络合剂与Ni离子也存在相互作用.通过制备条件优化,研制出高活性加氢脱硫催化剂RS-1100.中型装置评价结果表明,RS-1100催化剂的柴油超深度加氢脱硫活性比工业参比剂RS-1000更高,采用RS-1100催化剂在合适的加氢反应条件下可以生产满足欧Ⅴ排放标准的柴油.%NiMo/A1-2O3 catalyst was prepared by impregnation method using alumina support from appropriate pseudo-boehmite. The effect of Ni/(Ni + Mo) atomic ratio on the activity of NiMo/A1-2O3catalyst was investigated and optimized ratio was acquired. The activity of NiMo/A1-2O3 catalyst could be further improved by adding optimum amount of phosphorus promoter and chelating agent into the impregnation solution. The characterization of said impregnation solution by Raman spectroscopy and UV-Vis spectrophotometer showed that phosphorus-molybdenum heteropolyanions of [P2MO5O23]6- existed in the solution, besides, some interactions between chelating agent and Ni2+cations also happened. By optimizing preparation conditions, RS-1100 hydrodesulfurization catalyst with high activity was developed. The pilot-plant test results show that the activity of RS-1100 catalyst is higher than that of commercial RS-1000 catalyst at ultra-deep hydrodesulfurization stage, whereas, the bulk density of RS-1100 catalyst is lower. Diesel oil meeting European emission standard V can be produced by RS-1100 catalyst under suitable hydrogenation reaction conditions.

  17. 加氢脱硫催化剂载体的研究进展%Recent progress in the support of hydrodesulfurization catalysts

    Institute of Scientific and Technical Information of China (English)

    仝建波; 蔺阳; 刘淑玲; 温俊涛; 刘瑛瑛

    2014-01-01

    The research status and development tendency of hydrogenation desulfurization (HDS) catalyst support was outlined regarding the issue of high sulfur content in oil products. The development of HDS catalysts was reviewed in four aspects:single-component support,mixed oxide support,molecular sieve and modified support. Single component support,which laid emphasis on Al2O3,TiO2 and carbon support,was introduced in HDS reaction. Besides,mixed oxide support, which mainly includes aluminum-based,titanium-based binary mixed oxide support and ternary mixed oxide support,was summarized. Furthermore,molecular sieve was discussed,including MCM-41, SBA-15 and KIT. Ultimately,modified support,which contains modified MCM-41,modified SBA-15, modified carbon and other modified molecular sieve,was reported emphatically. In the future,modified supports,especially modified molecular sieves,will be paid increasing attention in the field of catalyst supports for HDS.%综述了加氢脱硫催化剂载体的研究现状及其发展趋势,分别从单组分载体、复合氧化物载体、分子筛和改性载体4个方面论述了加氢脱硫催化剂载体各自的优缺点。单组分载体重点介绍了A12O3、TiO2、炭载体;复合氧化物载体主要对铝基、钛基二元复合氧化物以及三元复合氧化物载体进行了综述;并且对以 MCM-41、SBA-15和 KIT 为代表的介孔分子筛做了介绍;还描述了近年来以改性 MCM-41、SBA-15、活性炭为主要研究对象的改性的分子筛。最后指出改性载体尤其是改性分子筛将是未来研究的焦点。

  18. Hydrodesulfurization catalysis by Chevrel phase compounds

    Science.gov (United States)

    McCarty, Kevin F.; Schrader, Glenn L.

    1985-12-24

    A process is disclosed for the hydrodesulfurization of sulfur-containing hydrocarbon fuel with reduced ternary molybdenum sulfides, known as Chevrel phase compounds. Chevrel phase compounds of the general composition M.sub.x Mo.sub.6 S.sub.8, with M being Ho, Pb, Sn, Ag, In, Cu, Fe, Ni, or Co, were found to have hydrodesulfurization activities comparable to model unpromoted and cobalt-promoted MoS.sub.2 catalysts. The most active catalysts were the "large" cation compounds (Ho, Pb, Sn), and the least active catalysts were the "small" cation compounds (Cu, Fe, Ni, Co.).

  19. Preparation of highly dispersed W/Al2O3 hydrodesulfurization catalysts via a microwave hydrothermal method: Effect of oxalic acid

    Directory of Open Access Journals (Sweden)

    Hao Wang

    2016-01-01

    Full Text Available A novel microwave hydrothermal method was developed to prepare highly dispersed W/Al2O3 catalysts, in which WO3 was deposited on alumina via precipitation between tungstate and nitric acid under microwave hydrothermal environment and oxalic acid was used as an additive. Moreover, the role of oxalic acid was investigated by varying its amount and the addition method. It is found that the catalysts show higher WO3 dispersion and weaker W–Al interaction than that prepared by the conventional impregnation method. The hydrothermal period can be extremely reduced to a few minutes, and highly dispersed WO3 can be achieved even without oxalic acid. When oxalic acid was added after the formation of H2WO4, it mainly acts as a modifier for reacting with the hydroxyl groups on alumina and has little effect on WO3 dispersion. When oxalic acid was divided into two parts, one for pretreating alumina and the remains for preventing the aggregation of H2WO4, it may effectively act as both dispersant and modifier, leading to further increased WO3 dispersion and weakened W–Al interaction. The catalysts prepared by the microwave hydrothermal method show superior dibenzothiophene hydrodesulfurization activity. This method provides rapidity, convenience and cost effectiveness for preparing active hydrotreating catalysts.

  20. Al-pillared montmorillonite-based NiMo catalysts for HDS and HDN of gas oil. Influence of the method and order of Mo and Ni impregnation

    Energy Technology Data Exchange (ETDEWEB)

    Salerno, P.; Mendioroz, S.; Lopez Agudo, A. [Instituto de Catalisis y Petroleoquimica CSIC, Camino de Valdelatas, s/n. Campus Universidad Autonoma de Madrid, 28049 Cantoblanco, Madrid (Spain)

    2004-03-08

    The effect of the impregnation method (co-impregnation and sequential) and the incorporation order of the active phases, Ni and Mo, on the structure and catalytic activity of NiMo hydrotreating catalysts supported on an Al-pillared montmorillonite has been investigated. The catalysts were characterised by X-ray diffraction, N{sub 2} adsorption, thermogravimetric analysis, temperature-programmed reduction, UV-Vis diffuse reflectance, in situ laser Raman, and X-ray photoelectron spectroscopies, and their catalytic behaviour tested in the hydrodesulphurisation (HDS) and hydrodenitrogenation (HDN) of gas oil. It was found that the catalyst prepared by co-impregnation of Ni and Mo was more active than those prepared by sequential impregnation, and of the latter ones, the most active was that in which Mo was impregnated prior to Ni. Characterisation results revealed that by co-impregnation, the dispersion of the Mo phase was significantly increased due to the presence of Ni and, on the other hand, more Ni stay together to Mo on the external surface of the clay, favouring thus the formation of Ni-Mo-O interaction species, precursors of the 'Ni-Mo-S' active phase. The relatively low activity of the sequentially impregnated Mo-Ni/Al-PILC catalyst was due to the absence of synergism between Ni and Mo because most of Ni was as Ni{sup 2+} ions into the octahedral layers of the clay, separated from the Mo phase. All NiMo bimetallic catalysts exhibited initially a better selectivity towards HDN than towards HDS reaction, probably due to their acidity properties.

  1. Effect of phosphorus on the hydrodesulfurization and hydrodenitrogenation performance of presulfided NiMo/Al2O3 catalyst%磷对预硫化型NiMo/Al2O3催化剂加氢脱硫脱氮性能的影响

    Institute of Scientific and Technical Information of China (English)

    相春娥; 柴永明; 樊晶; 刘晨光

    2011-01-01

    利用等体积浸渍法制备了不同磷含量的预硫化型NiMo/Al2O3催化剂,并利用XRD、BET、TPR和HRTEM等分析方法对其进行了表征,研究了磷对其加氢脱硫脱氮性能的影响.结果表明,由于预硫化型NiMo加氢催化剂上活性组分和载体的相互作用较弱,MoS2或Ni-Mo-S相主要以TypeⅡ形式存在,磷通过增加MoS2的堆积层数、减小片晶长度提高了MoS2的分散度.TPR结果表明磷仅提高了金属硫化物中Ni-Mo-S相的比例,而对Ni-Mo-S相和体相MoS2中的金属-硫键的键合强度没有影响.NiMoP-1.2催化剂(磷负载量为1.2%)表面MoS2的分散度最高,同时也具有最高的加氢脱硫(HDS)选择性和加氢脱氮(HDN)活性;过高磷含量(NiMoP-1.8,磷负载量为1.8%)则造成MoS2分散度降低,催化剂的比表面积、孔径和孔容也减小,导致其HDS和HDN反应性能下降.%Phosphorus promoted presulfided NiMo/A12 O3 catalysts were prepared by successive incipient wemess impregnation and characterized by XRD, N2-physisorption, TPR and HRTEM. The effect of phosphorus on the hydrodesulfurization ( HDS ) hydrodenitrogenation (HDN) performance of the presulfided NiMo/Al203 catalyst was investigated. The results indicate that the main active phase is type Ⅱ MoS2 or Ni-Mo-S phase because of theft weak interaction with the support. The incorporation of phosphorus in the catalyst enhances the dispersion of MoS2 particles by increasing the stacking number and reducing the slab length.Phosphorus has no influence on the metal-sulfur bonding energies in the Ni-Mo-S phases and bulk MoS2, but it increases the proportion of Ni-Mo-S phases in the metal sulfides. NiMoP-1.2 catalyst ( containing 1.2% phosphoms) exhibits high hydrogenation (HYD) selectivity in the HDS of dibenzothiophene (DBT) and high HDN ratio of quinoline, which can be attributed to its high dispersion of the active phase. The HYD activity in HDS and HDN ratio on NiMoP-1.8 catalyst with excess phosphorus ( 1.8

  2. Probing hydrodesulfurization over bimetallic phosphides using monodisperse Ni2-xMxP nanoparticles encapsulated in mesoporous silica

    Science.gov (United States)

    Danforth, Samuel J.; Liyanage, D. Ruchira; Hitihami-Mudiyanselage, Asha; Ilic, Boris; Brock, Stephanie L.; Bussell, Mark E.

    2016-06-01

    Metal phosphide nanoparticles encapsulated in mesoporous silica provide a well-defined system for probing the fundamental chemistry of the hydrodesulfurization (HDS) reaction over this new class of hydrotreating catalysts. To investigate composition effects in bimetallic phosphides, the HDS of dibenzothiophene (DBT) was carried out over a series of Ni-rich Ni2-xMxP@mSiO2 (M = Co, Fe) nanocatalysts (x ≤ 0.50). The Ni2-xMxP nanoparticles (average diameters: 11-13 nm) were prepared by solution-phase arrested precipitation and encapsulated in mesoporous silica, characterized by a range of techniques (XRD, TEM, IR spectroscopy, BET surface area, CO chemisorption) and tested for DBT HDS activity and selectivity. The highest activity was observed for a Ni1.92Co0.08P@mSiO2 nanocatalyst, but the overall trend was a decrease in HDS activity with increasing Co or Fe content. In contrast, the highest turnover frequency (TOF) was observed for the most Co- and Fe-rich compositions based on sites titrated by CO chemisorption. IR spectral studies of adsorbed CO on the Ni2-xMxP@mSiO2 catalysts indicate that an increase in electron density occurs on Ni sites as the Co or Fe content is increased, which may be responsible for the increased TOFs of the catalytic sites. The Ni2-xMxP@mSiO2 nanocatalysts exhibit a strong preference for the direct desulfurization pathway (DDS) for DBT HDS that changes only slightly with increasing Co or Fe content.

  3. Synthesis, characterization and hydrotreating performance of supported tungsten phosphide catalysts

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Supported tungsten phosphide catalysts were prepared by temperature-programmed reduction of their precursors (supported phospho-tungstate catalysts) in H2 and characterized by X-ray diffraction (XRD),BET,temperature-programmed desorption of ammonia (NH3-TPD) and X-ray photoelectron spectroscopy (XPS).The reduction-phosphiding processes of the precursors were investigated by thermogravimetry and differential thermal analysis (TG-DTA) and the suitable phosphiding temperatures were defined.The hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) activities of the catalysts were tested by using thiophene,pyridine,dibenzothiophene,carbazole and diesel oil as the feed-stock.The TiO2,γ-Al2O3 supports and the Ni,Co promoters could remarkably increase and stabilize active W species on the catalyst surface.A suitable amount of Ni (3%-5%),Co (5%-7%) and V (1%-3%) could increase dispersivity of the W species and the BET surface area of the WP/γ-Al2O3 catalyst.The WP/γ-Al2O3 catalyst possesses much higher thiophene HDS and carbazole HDN activities and the WP/TiO2 catalyst has much higher dibenzothiophene (DBT) HDS and pyridine HDN activities.The Ni,Co and V can obviously promote the HDS activity and inhibit the HDN activity of the WP/γ-Al2O3 catalyst.The G-Ni5 catalyst possesses a much higher diesel oil HDS activity than the sulphided industrial NiW/γ-Al2O3 catalyst.In general,a support or promoter in the WP/γ-Al2O3 catalyst which can increase the amount and dispersivity of the active W species can promote its HDS and HDN activities.

  4. Effect of H{sub 2}S partial pressure on the HDS of dibenzothiophene and 4,6-dimethyldibenzothiophene over sulfided NiMoP/Al{sub 2}O{sub 3} and CoMoP/Al{sub 2}O{sub 3} catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Rabarihoela-Rakotovao, V.; Brunet, S.; Perot, G. [UMR CNRS 6503, Catalyse en Chimie Organique, Universite de Poitiers, 40 avenue du Recteur Pineau, 86022 Poitiers, Cedex (France); Diehl, F. [Institut Francais du Petrole, IFP-Lyon, Catalysis and Separation Division, Heterogeneous Catalysis Department, BP 3, 69390 Vernaison (France)

    2006-06-07

    The effect of hydrogen sulfide (H{sub 2}S) partial pressure on the hydrodesulfurization (HDS) of dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (46DMDBT) was studied over commercial NiMoP/Al{sub 2}O{sub 3} and CoMoP/Al{sub 2}O{sub 3} catalysts under conditions close to those commonly used in the hydrotreating of diesel fuels (280 or 340{sup o}C; total pressure between 2.5 and 5.5MPa). The sulfur compounds diluted in n-heptane were in proportions representative of those found in diesel fuels (0.0014MPa of DBT or 46DMDBT, 0.0058-0.1MPa of H{sub 2}S generated from dimethyldisulfide). A significant negative effect of H{sub 2}S on the HDS of the dibenzothiophenes (DBT and 46DMDBT) was observed whatever the total pressure (2.5-5.5MPa) and the catalyst used. However, the reactivity of DBT was more reduced than that of 46DMDBT. Moreover, the 'direct desulfurization pathway' (DDS) of both reactants was more inhibited by H{sub 2}S than the so-called 'hydrogenation pathway' (HYD) over the two catalysts. It was also found that the NiMoP/Al{sub 2}O{sub 3} catalyst was more sensitive to H{sub 2}S than its CoMoP/Al{sub 2}O{sub 3} counterpart whatever the experimental conditions. Several hypotheses were considered and discussed to explain these findings: specific centres for each of the two reactions (DDS and HYD) or centres being similar in nature (sulfur vacancies associated to sulfur anions) but which would differ in their acid-base properties. It was also suggested that the centres could be identical but that DDS and HYD could have different rate-limiting steps which would not involve the same part of the dual site so that their sensitivity to H{sub 2}S would be different. (author)

  5. Modification of nickel supported over ZnO for HDS of thiophene with neodymium

    Institute of Scientific and Technical Information of China (English)

    SHI Qiujie; LI Zhijun; LI Bin; HU Xuejuan

    2009-01-01

    Ni/ZnO and Ni-Nd/ZnO were prepared by impregnation method, and the catalytic activities of Ni/ZnO and Ni-Nd/ZnO for hy-drodesulfurization (HDS) of thiophene were tested. The catalysts were characterized by temperature programmed reduction(TPR), H2-TPD and NH3-TPD.The results showed that Ni-Nd/ZnO exhibited higher catalytic activity than Ni/ZnO, because the active surface area and the amount of H2 adsorption were increased by the addition of Nd. Compared with Ni/ZnO, Ni-Nd/ZnO showed more H2 adsorbing centers and stronger acid property, which were also in favor of the reaction

  6. 二苯并噻吩在分散型钼催化剂和原位产生的氢存在下的加氢脱硫Ⅲ.催化剂前身物、硫化氢、一氧化碳和水对反应的影响%HDS OF DBT USING in situ GENERATED HYDROGEN IN THE PRESENCE OF DISPERSED Mo CATALYSTS Ⅲ. Effects of Catalyst Precursors, H2S, CO and H2O

    Institute of Scientific and Technical Information of China (English)

    刘晨光; Flora T.T.Ng

    1999-01-01

    研究了水水/甲苯乳化液中二苯并噻吩(硫芴)在分散型钼酸、磷钼酸和四硫钼酸铵催化剂存在下的加氢脱硫反应.反应在高压釜中于340℃及三种不同的气氛即H2,H2/H2O和CO/H2O(CO和H2O经水煤气转换反应(WGSR)产生原位氢)的存在下进行.用GC和GC-MS鉴定、分析了气体和液体产物的组成.结果表明:对硫芴的加氢脱硫反应,在分散型四硫钼酸铵催化剂存在下,原位产生的氢的效果仅比加入的氢气稍好,而在分散型钼酸和磷钼酸催化剂存在下,原位产生的氢远比加入的氢气有效.实验结果还表明:硫化氢能显著提高分散型钼酸和磷钼酸催化剂的加氢脱硫活性,但在分散型四硫钼酸铵催化剂存在下,硫化氢能促进加氢反应而抑制氢解反应.一氧化碳和水均选择性地抑制氢解反应.%The hydrodesulfurization (HDS) of dibenzothiophene (DBT) was investigated using dispersed catalyst precursors molybdic acid (MA), phosphomolybdic acid (PMA), and ammonium tetrathiomolybdate (ATTM). The results indicated that with ATTM catalyst, in situ hydrogen was slightly more active than the externally supplied molecular H2 for HDS of DBT, but is not so active as with MA and PMA catalysts. The experimental results also indicated that H2S has a significant promotional effect on the catalytic activity of MA or PMA catalyst. While the H2 S promoted the hydrogenation pathway, inhibited the hydrogenolysis pathway with ATTM catalyst.Both CO and H2O selectively inhibited the hydrogenolysis route.

  7. On the Interaction between Co- and Mo-complexes in impregnation solutions used for the preparation of Al2O3-supported HDS catalysts: a combined Raman/UV-Vis-NIR spectroscopy study

    NARCIS (Netherlands)

    Bergwerff, J.A.; Visser, T.; Weckhuysen, B.M.

    2008-01-01

    Research has been carried out on the formation of cobalt (Co) and molybdenum (Mo) complexes in CoMo-solutions, which are used for the preparation of Al2O3-supported hydrodesulphurization (HDS) catalysts. Aim of this study was to obtain more insight into possible Co–Mo interactions and their implicat

  8. Dispersion of MoS{sub 2} on meso-porous materials: application in hydro-desulfurization; Dispersion de MoS{sub 2} sur materiaux mesoporeux: application en hydrodesulfuration

    Energy Technology Data Exchange (ETDEWEB)

    Sampieri, A.; Breysse, M.; Blanchard, J.; Fajerwerg, K.; Louis, C. [Paris-6 Univ., Lab. de Reactivite de Surface, UMR 7609 CNRS, 75 (France); Perot, G. [Poitiers Univ., Lab. de Catalyse en Chimie Organique, UMR 6.503 CNRS, 86 (France)

    2004-07-01

    Meso-porous materials are promising model catalyst supports for HDS (hydro-desulfurization) reaction. These materials have large specific surfaces which could lead to improve the dispersion of the active phase (MoS{sub 2}) compared to conventional supports. For this study, meso-porous materials purely silicic such as MCM-41 (S{sub BET}=1040 m{sup 2}g{sup -1}, {phi}{sub pore}=3.3 nm) and the SBA-15 (S{sub BET}=790 m{sup 2}g{sup -1}, {phi}{sub pore}=7.0 nm) have been synthesized and a Grace silica (S{sub BET}=320 m{sup 2}g{sup -1}, {phi}{sub pore}=13.5 nm) has been used as a reference support. The preparation conditions of these catalysts are detailed. It has been shown in particular that small MoO{sub 2} particles localized mainly in the porosity of the two meso-porous supports are formed, these particles being smaller than those observed on the Grace silica. The HDS reaction of the DBT is then carried out in a fixed bed dynamic reactor under H{sub 2} pressure (T=340 C and P{sub T}=40 bar, 13.5 mmol{sub DBT}L{sup -1} in decalin). The meso-porous catalysts have shown an activity twice higher than those observed in the catalyst prepared on the Grace silica. (O.M.)

  9. Microkinetic interpretation of HDS/HYDO selectivity of the transformation of a model FCC gasoline over transition metal sulfides

    Energy Technology Data Exchange (ETDEWEB)

    Daudin, A. [UMR CNRS 6503, Catalyse en Chimie Organique, Universite de Poitiers, Faculte des Sciences Fondamentales et Appliquees, 40 Avenue du Recteur Pineau, 86022 Poitiers Cedex (France); IFP-Lyon, Direction Catalyse et Separation, BP 3, 69390 Vernaison (France); Lamic, A.F.; Perot, G.; Brunet, S. [UMR CNRS 6503, Catalyse en Chimie Organique, Universite de Poitiers, Faculte des Sciences Fondamentales et Appliquees, 40 Avenue du Recteur Pineau, 86022 Poitiers Cedex (France); Raybaud, P. [IFP, Direction Chimie et Physico-Chimie Appliquees, 1-4 Av. de Bois Preau, 92858 Rueil Malmaison (France); IFP-Lyon, Direction Catalyse et Separation, BP 3, 69390 Vernaison (France); Bouchy, C. [IFP-Lyon, Direction Catalyse et Separation, BP 3, 69390 Vernaison (France)

    2008-01-15

    The conversion of a model FCC gasoline (composed of 2-methylthiophene (2MT), 2,3-dimethylbut-2-ene (23DMDB2N) and orthoxylene in n-heptane) under realistic hydrodesulfurization (HDS) conditions was investigated over a series of transition monometallic sulfides (Ni{sub 3}S{sub 2}, PdS, Co{sub 9}S{sub 8}, Rh{sub 2}S{sub 3}, RuS{sub 2}, PtS and MoS{sub 2}) and unsupported transition bimetallic sulfide catalysts (NiMoS and CoMoS). The results reveal for the first time that a volcano curve relationship exists between the ab initio calculated sulfur-metal bond energy, E(MS), descriptor of bulk TMS and their activities in olefin hydrogenation and in alkylthiophene desulfurization measured simultaneously. In particular, Rh{sub 2}S{sub 3} with an intermediate sulfur-metal bond energy of 119 kJ/mol is the most active catalyst in both case hydrogenation of the olefin and in HDS of a sulfur compound. Furthermore, the HDS/HYDO selectivity which is the most important parameter in the deep HDS of gasoline, presents a maximum for the NiMoS catalyst with E(MS) of 128 kJ/mol. A microkinetic model based on Broensted-Evans-Polanyi relationships and the competitive adsorption of the sulfur molecule and alkene on the catalytic site is proposed to give a rational interpretation of the experimental catalytic results. (author)

  10. Preparation of ZnNiMo/{gamma}-alumina catalysts from recycled Ni for hydrotreating reactions

    Energy Technology Data Exchange (ETDEWEB)

    Linares, Carlos F.; Lopez, Julio [Laboratorio de Catalisis y Metales de Transicion, Facultad de Ciencias y Tecnologia, Departamento de Quimica, Universidad de Carabobo, Valencia Edo Carabobo, Apartado Postal 3336 (Venezuela); Scaffidi, Adriana; Scott, Carlos E. [Centro de Catalisis, Petroleo y Petroquimica, Universidad Central de Venezuela, Facultad de Ciencias, Apartado 47102, Los Chaguaramos, Caracas (Venezuela)

    2005-09-18

    Ni, recovered from Ni-Cd cellular phone batteries, was used in the preparation of ZnNiMo/Al{sub 2}O{sub 3} catalysts. The catalysts were characterized by temperature programmed reductions (TPR), surface area determinations (BET) and chemical analysis. Vanadyl octaethyl porphyrin (VOOEP) hydrodeporphyrinization (HDP) and thiophene hydrodesulfurization (HDS) were used as catalytic tests. It was found that the addition of Zn increases the ratio between octahedral and tetrahedral Mo in ZnMo and ZnNiMo catalysts, and that Ni addition lowers the reduction temperature of Mo species. Both results induce a positive synergetic effect for HDP and HDS reactions. An activity maximum was found for the catalyst with a Zn/(Zn+Ni) atomic ratio equal to 0.29, for both reactions. Finally, the use of a possible pollutant (Ni-Cd batteries) to produce a catalyst to eliminate contaminants in fuels was shown to be feasible.

  11. Characterization of A Sulfided Mo/γ-Al2O3 Catalyst by Low Temperature FTIR Spectroscopy of Adsorbed CO and Its Thiophene HDS Activity%硫化态Mo/γ-Al2O3催化剂活性位的低温CO-FTIR方法表征及噻吩HDS活性

    Institute of Scientific and Technical Information of China (English)

    齐兴义; 徐春明; 刘植昌; 李文钊; 辛勤

    2001-01-01

    A sulfided Mo/γ-Al2O3 catalyst was characterized by low-temperature FTIR spectroscopy of adsorbed carbon monoxide, with its HDS activity being investigated with thiophene as a mold substrate. On the basis of the results here, the conclusion may be obtained that the sites for CO adsorption should be the active reaction centers of thiophene HDS.

  12. Effect of Operation Variables on Hydrodenitrogenation and Hydrodesulfurization over NiMo/Al2O3 Catalysts

    Institute of Scientific and Technical Information of China (English)

    段爱军; 徐春明; 林世雄

    2003-01-01

    Using the JQ-Ⅱ high pressure hydrogenation micro-reactor unit, the reactivity of Athabasca bitumen derived heavy gas oil was studied over commercial and homemade hydrotreating catalysts. The effects of catalyst preparation variables and the influences of operation conditions, such as pressure, temperature, hydrogen/oil ratio and space velocity were also examined. It was shown that the optimal concentrations of the active components were 5% of NiO, 20% of MoO3 and 3.5% of phosphorus (by mass), and the suitable operation conditions were determined experimentally.

  13. HDS OF DBT USING in situ GENERATED HYDROGEN IN THE PRESENCE OF DISPERSED Mo CATALYSTS Ⅰ. Product Distribution and Reaction Network%二苯并噻吩在分散型钼催化剂和原位产生的氢存在下的加氢脱硫Ⅰ.产物分布和反应网络

    Institute of Scientific and Technical Information of China (English)

    刘晨光; Flora T.T.Ng

    1999-01-01

    研究了水/甲苯乳化液中二苯并噻吩(硫芴,DBT)在分散型钼酸和磷钼酸催化剂存在下的加氢脱硫反应.反应在高压釜中于340℃及经水煤气转换反应(WGSR)产生的原位氢存在下进行.用GC和GC-MS 鉴定、分析了气体和液体产物的组成.结果表明:在反应过程中部分加氢的中间产物1,2,3,4-四氢硫芴(4H-DBT)和1,2,3,4,10,11-六氢硫芴(6H-DBT)的浓度相当高,但二联苯的浓度相对较低,说明加氢路径与氢解路径相当.提出的硫芴加氢脱硫反应网络包含两个反应途径:噻吩环先直接氢解脱硫,紧接着苯环加氢途径;苯环先加氢,然后噻吩环氢解脱硫途径.同时,还包含环烷环的异构化反应.%The hydrodesulfurization (HDS) of dibenzothiophene (DBT) in H2O/C6H5CH3 emulsion was investigated using dispersed catalyst precursors molybdic acid and phosphomolybdic acid. The HDS experiments were performed in an autoclave at 340℃ using in situ generated hydrogen from CO/H2O via the water gas shift reaction. The results indicated that the partially hydrogenated intermediates 1, 2, 3, 4-tetrahydrodibenzothiophene and 1, 2, 3, 4, 10, 11-hexahydrodibenzothiophene were present in quite high concentration, while diphenyl was present in a relatively lower concentration, so the hydrogenation route is comparable to the hydrogenolysis route.A reaction network involving two pathways, direct hydrogenolysis-hydrogenation, and hydrogenation-hydrogenolysis, as well as isomerisation of aliphatic rings was proposed.

  14. Aqueous-Phase Preparation of Model HDS Catalysts on Planar Alumina Substrates: Support Effect on Mo Adsorption and Sulfidation.

    Science.gov (United States)

    Bara, Cédric; Plais, Lucie; Larmier, Kim; Devers, Elodie; Digne, Mathieu; Lamic-Humblot, Anne-Félicie; Pirngruber, Gerhard D; Carrier, Xavier

    2015-12-23

    The role of the oxide support on the structure of the MoS2 active phase (size, morphology, orientation, sulfidation ratio, etc.) remains an open question in hydrotreating catalysis and biomass processing with important industrial implications for the design of improved catalytic formulations. The present work builds on an aqueous-phase surface-science approach using four well-defined α-alumina single crystal surfaces (C (0001), A (112̅0), M (101̅0), and R (11̅02) planes) as surrogates for γ-alumina (the industrial support) in order to discriminate the specific role of individual support facets. The reactivity of the various surface orientations toward molybdenum adsorption is controlled by the speciation of surface hydroxyls that determines the surface charge at the oxide/water interface. The C (0001) plane is inert, and the R (11̅02) plane has a limited Mo adsorption capacity while the A (112̅0) and M (101̅0) surfaces are highly reactive. Sulfidation of model catalysts reveals the highest sulfidation degree for the A (112̅0) and M (101̅0) planes suggesting weak metal/support interactions. Conversely, a low sulfidation rate and shorter MoS2 slabs are found for the R (11̅02) plane implying stronger Mo-O-Al bonds. These limiting cases are reminiscent of type I/type II MoS2 nanostructures. Structural analogies between α- and γ- alumina surfaces allow us to bridge the material gap with real Al2O3-supported catalysts. Hence, it can be proposed that Mo distribution and sulfidation rate are heterogeneous and surface-dependent on industrial γ-Al2O3-supported high-surface-area catalysts. These results demonstrate that a proper control of the γ-alumina morphology is a strategic lever for a molecular-scale design of hydrotreating catalysts.

  15. Session 4: Enhanced sulfur resistance and catalytic properties of Pd-Pt supported on TiO{sub 2} - modified Al{sub 2}O{sub 3} in the hydrogenation of biphenyl and HDS of dibenzothiophene

    Energy Technology Data Exchange (ETDEWEB)

    Nunez, S.; Montesinos, A.; Viveros, T.; Los Reyes, J.A. de [Universidad Autonoma Metropolitana-Iztapalapa (Mexico)

    2004-07-01

    In the hydrotreatment (HDT) of petroleum cuts to produce diesel, the selection of active and highly selective catalysts for hydrogenation (HYD) of aromatics is a fundamental issue in the second stage of multi-staged processes. It is well know that precious metals (Pd-Pt mainly) are suitable for this reaction. However, sulfur compounds at low concentration may poison these catalysts. Thus, this work focuses on the evaluation in the hydrogenation of an aromatic compound of Pd-Pt catalysts supported on TiO{sub 2}-modified Al{sub 2}O{sub 3} by using two reactions in presence of sulfur, the hydrogenation (HYD) of biphenyl (BP) and the hydrodesulfurization (HDS) of dibenzothiophene (DBT). The obtained experimental results are given and explained. (O.M.)

  16. Two stage leaching of activated spent HDS catalyst and solvent extraction of aluminium using organo-phosphinic extractant, Cyanex 272.

    Science.gov (United States)

    Park, Kyung Ho; Mohapatra, Debasish; Nam, Chul-Woo

    2007-09-05

    Spent catalyst generally contains valuable metals like Mo, Co, Ni on a supporting material, such as gamma-A1(2)O(3). In the present study, a two stage alkali/acid leaching process is proposed to selectively target molybdenum and cobalt/nickel separately to facilitate the downstream processing. Prior to the leaching, the spent catalyst was calcined at 500 degrees C to remove C and S; and to convert metal sulphides to metal oxides. 98% Mo, 93% Co and 90% Ni was effectively recovered by this process. The sulphuric acid leaching of spent catalyst, previously treated by alkali solutions to remove Mo, yielded a solution rich in Ni, Co and Al. In order to recover Co and Ni, the Al impurity must be eliminated. The extraction and stripping of Al has been carried out using the organo-phosphinic extractant, Cyanex 272 diluted in carbon tetrachloride. Quantitative Al extraction efficiency was achieved with 1.0M Cyanex 272 in two stages at an aqueous:organic (A:O) phase ratio of 1:1 and equilibrium pH of 3.2. Complete stripping of Al from the loaded organic was carried out using 2M H(2)SO(4) at an A:O phase ratio of 1:1. The extraction reaction proceeded via the cation exchange mechanism and the extracted species was assumed to be AlA(3).3HA. The extraction of Al was carried out in the presence of various ions to ascertain the tolerance limit of individual ions. The regenerated solvent was successfully used for 8 cycles without any significant loss of extraction efficiency, suggesting that Cyanex 272 is extremely stable under present experimental conditions.

  17. Study to improve the quality of a Mexican straight run gasoil over NiMo/{gamma}-Al{sub 2}O{sub 3} catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Dominguez-Crespo, M.A. [Instituto Politecnico Nacional, Departamento de Metalurgia y Materiales, A.P. 75-876, 07300 Mexico D.F. (Mexico)]. E-mail: adcrespo2000@yahoo.com.mx; Diaz-Garcia, L. [Instituto Mexicano del Petroleo, Avenida Eje Central Lazaro Cardenas No. 152, Col. San Bartolo Atepehuacan, 07730 Mexico D.F. (Mexico); Arce-Estrada, E.M. [Instituto Politecnico Nacional, Departamento de Metalurgia y Materiales, A.P. 75-876, 07300 Mexico D.F. (Mexico); Torres-Huerta, A.M. [Instituto Politecnico Nacional, Departamento de Metalurgia y Materiales, A.P. 75-876, 07300 Mexico D.F. (Mexico); Cortez de la Paz, M.T. [Instituto Mexicano del Petroleo, Avenida Eje Central Lazaro Cardenas No. 152, Col. San Bartolo Atepehuacan, 07730 Mexico D.F. (Mexico)

    2006-11-30

    Four NiMo catalyst supported on Al{sub 2}O{sub 3} with different textural properties have been studied in the hydrodesulfurization (HDS), hydrodenitrogenation (HDN) and hydrodearomatization (HDA) of a Mexican straight run gasoil (SRGO). All reactions were carried out at three different temperatures 613, 633, and 653 K. Alumina supports were analysed by pyridine FTIR-TPD and nitrogen physisorption in order to determine their surface acidity and textural properties, respectively. TPR studies of the NiMo catalysts were analysed to correlate their hydrogenating properties. Metallic particles were characterized (after sulfidation) using transmission electron microscopy (TEM). Catalytic activities are discussed in relation to the physicochemical properties of NiMo catalysts. The importance of textural properties on coke deposition has been emphasized. The results of catalytic activity of these materials varied depending on dispersed MoS particles and pore distribution in final catalysts. The optimum pore diameter was found around 80 A for HDS and HDN.

  18. HDS: Hierarchical Data System

    Science.gov (United States)

    Pearce, Dave; Walter, Anton; Lupton, W. F.; Warren-Smith, Rodney F.; Lawden, Mike; McIlwrath, Brian; Peden, J. C. M.; Jenness, Tim; Draper, Peter W.

    2015-02-01

    The Hierarchical Data System (HDS) is a file-based hierarchical data system designed for the storage of a wide variety of information. It is particularly suited to the storage of large multi-dimensional arrays (with their ancillary data) where efficient access is needed. It is a key component of the Starlink software collection (ascl:1110.012) and is used by the Starlink N-Dimensional Data Format (NDF) library (ascl:1411.023). HDS organizes data into hierarchies, broadly similar to the directory structure of a hierarchical filing system, but contained within a single HDS container file. The structures stored in these files are self-describing and flexible; HDS supports modification and extension of structures previously created, as well as functions such as deletion, copying, and renaming. All information stored in HDS files is portable between the machines on which HDS is implemented. Thus, there are no format conversion problems when moving between machines. HDS can write files in a private binary format (version 4), or be layered on top of HDF5 (version 5).

  19. 柠檬酸对Ni2P/TiO2-Al2O3催化剂加氢脱硫性能的影响%Effect of Citric Acid on the Hydrodesulfurization Performance of Ni2P/TiO2-Al2O3 Catalyst

    Institute of Scientific and Technical Information of China (English)

    宋华; 张永江; 宋华林; 代敏

    2012-01-01

    采用溶胶-凝胶法制备了TiO2-Al2O3复合载体,以柠檬酸(CA)为络合剂采用浸渍法制备了Ni2P负载的TiO2-Al2O3复合载体催化剂,并用X射线衍射(XRD)、N2吸附比表面积测定、H2程序升温氢还原(H2-TPR)、程序升温氧化(TPO)、X射线光电子能谱(XPS)技术对催化剂的结构和性质进行了表征,考察了CA/Ni摩尔比对在Ni2P/TiO2-Al2O3催化剂上进行的二苯并噻吩(DBT)加氢脱硫(HDS)性能的影响.结果表明:适量的CA可以丰富催化剂的孔道,提高催化剂的比表面积.当n(CA)/n(Ni)=2∶1时,催化剂的比表面积达到126.75 m2·g-1,与不加CA时相比,提高了57.05 m2·g-1.调节n(CA)/n(Ni)能够改善活性相的分布,改变活性相的种类;引入CA使Ni和P前驱体的还原温度明显降低,促进活性相Ni2P的生成,一定程度上能够抑制催化剂表面炭的形成和沉积,提高其稳定性.n(CA)/n(Ni)=2∶1时,催化剂具有最好的加氢脱硫活性,在360℃,3.0 MPa,氢油比为500(V/V),液时体积空速为2.0 h-1的条件下,二苯并噻吩转化率为99.5%,可将模拟油中硫含量由2%(w)降低到0.01%(w).%ATiO2-AI2O3 complex support was prepared by the sol-gel method. Nickel phosphide catalyst, Ni2P/TiO2-AI2O3, with citric acid (CA) as a chelating agent, was prepared by impregnation. The catalyst was characterized by X-ray diffraction (XRD), BET specific surface area measurements, H2-temperature programmed reduction (TPR) and temperature programmed oxidation (TPO), and X-ray photoelectron spectroscopy (XPS). The effects of the molar ratio of CA to Ni on catalyst activity for hydrodesulfurization (HDS) of dibenzothiophene (DBT) were studied. Addition of an appropriate amount of CA into the catalyst can change the pores of the Ni2P/TiO2-Al2O3 catalyst, increasing the surface area. The specific surface area reached 126.75 m2·g-1 for n(CA)/n(Ni) of 2/1, an improvement of 57.05 m2·g-1 compared with the catalyst without CA. Regulating n(CA)/n(Ni) can

  20. 柴油超深度加氢脱硫机理及氮化物影响的研究进展%Study on mechanism of diesel ultra-deep hydrodesulfurization and impact of nitrogen compounds

    Institute of Scientific and Technical Information of China (English)

    白天忠; 刘继华; 柳伟; 宋永一; 孙厚祥; 包洪洲

    2011-01-01

    The mechanisms of diesel ultra-deep desulfurization and impact of nitrogen compounds are introduced. The forms of nitrogen compounds, the relative reaction rate and HDS reaction route are specifically studied. The results show that the non-thiophene sulfides have a higher HDS activity, which can directly be hydrogenolyzed into hydrocarbons and H2S on the active site of hydrogenation catalysts. As the acid site of catalyst has a promoting effect on cracking reaction in hydrogenation process, the desulfurization rate and service life of catalyst should be optimally considered. The basic nitrogen compounds have a greater inhibition on HDS than non-basic nitrogen compounds. Different catalysts have different contaminant resistance performances. The impacts of nitrogen compounds on two HDS routes are different, I. E. The inhibition on HYD is greater than on DDS. The study on the mechanism of diesel ultra-deep hydrodesulfurization and inhibition of nitrogen compounds provides a good guideline for development of high-activity high-inhibition-resistance catalysts which can mitigate process conditions and extend catalyst life.%介绍了柴油超深度加氢脱硫(HDS)机理及氮化物对其的影响.介绍了硫化物存在形式、相对反应速率及其HDS反应路径.结果表明:非噻吩类硫化物HDS活性较高,在加氢催化剂活性中心上直接氢解生成相应的烃和H2S;催化剂的酸性在加氢精制工艺中对裂化反应有促进作用,必须考虑到脱硫率和催化剂寿命的最优化选择;碱性氮化物比非碱性氮化物对HDS的抑制作用强,不同催化剂的抗氮化物毒化能力不同,氮化物对HDS的两种路径影响不同,对加氢(HYD)路径的抑制作用强于直接氢解(DDS)路径;柴油馏分超深度HDS机理及氮化物对其抑制机理的研究,可以指导高活性、抗抑制剂催化剂的开发,从而缓和工艺条件,延长催化剂寿命.

  1. In situ X-ray absorption fine structure studies on the structure of nickel phosphide catalyst supported on K-USY

    CERN Document Server

    Kawai, T; Suzuki, S

    2003-01-01

    Local structure around Ni in a nickel phosphide catalyst supported on K-USY was investigated by an situ X-ray absorption fine structure (XAFS) method during the reduction process of the catalyst and the hydrodesulfurization (HDS) reaction of thiophene. In the passivated sample, Ni phosphide was partially oxidized but after the reduction, 1.1 nm diameter Ni sub 2 P particles were formed with Ni-P and Ni-Ni distances at 0.218 and 0.261 nm, respectively, corresponding to those of bulk Ni sub 2 P. In situ XAFS cleary revealed that the Ni sub 2 P structure was stable under reaction conditions and was an active structure for the HDS process.

  2. 载体的酸性和钠含量对Ni-Mo催化剂加氢脱硫性能的影响%THE EFFECT OF ACIDITY AND SODIUM CONTENT OF SUPPORT ON THE HDS PERFORMACE OF Ni-Mo CATALYSTS

    Institute of Scientific and Technical Information of China (English)

    姜凤华; 王安杰; 胡永康; 任靖

    2011-01-01

    A series of Ni-Mo HDS catalysts were prepared by using various supports including MCM-41, NaMCM-41, HY, NaY and their mechanical mixtures. The supports and the catalysts were characterized by TPR, UV-Vis, ICP-AES and IR. The HDS activities of these prepared catalysts were evaluated using dibenzothiophene (DBT) as model compound to study the effect of support acidity and sodium content on the HDS activity of catalyst. It is found that the HDS activities of these catalysts are related to the Br(o)nsted acidity and sodium contents of the supports: Br(o)nsted acidity has a positive effect on the HDS activity of the supported Ni-Mo catalysts while Na+ has a negative effect. Furthermore, it seems that some synergetic effects exist between the acid sites of support and the active components linking by spillover hydrogen as shown from the results of TPR characterization and HDS evaluation.%用MCM-41和Na交换的MCM-41(NaMCM-41)以及它们与NaY和HY沸石的机械混合物为载体负载Ni-Mo制备了加氢脱硫(HDS)催化剂,用ICP-AES、吡啶吸附红外、UV-Vis、TPR等对载体和所制备的催化剂进行了表征.以二苯并噻吩(DBT)为模型化合物评价了催化剂的HDS活性,考察了载体的酸性和Na含量对催化剂HDS活性的影响.发现Ni-Mo催化剂的HDS活性与载体的Na+含量和B酸量有关,而与L酸量关系不大.通过催化剂的HDS反应和TPR表征结果,发现在载体酸中心和活性组分之间可能存在着以溢流氢为纽带的协同作用.

  3. Regeneration of Hydrotreating and FCC Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    CM Wai; JG Frye; JL Fulton; LE Bowman; LJ Silva; MA Gerber

    1999-09-30

    Hydrotreating, hydrocracking, and fluid catalytic cracking (FCC) catalysts are important components of petroleum refining processes. Hydrotreating and hydrocracking catalysts are used to improve the yield of high-quality light oil fractions from heavier crude oil and petroleum feedstocks containing high levels of impurities. FCC catalysts improve the yield of higher octane gasoline from crude oil. Residuum hydrotreating and cracking catalysts are susceptible to irreversible deactivation caused by adsorption of sulfur and by metals impurities, such as vanadium and nickel. The gradual buildup of these impurities in a hydrotreating catalyst eventually plugs the pores and deactivates it. Nickel and vanadium adversely affect the behavior of cracking catalysts, reducing product yield and quality. Replacing deactivated catalysts represents a significant cost in petroleum refining. Equally important are the costs and potential liabilities associated with treating and disposing spent catalysts. For example, recent US Environmental Protection Agency rulings have listed spent hydrotreating and hydrorefining catalysts as hazardous wastes. FCC catalysts, though more easily disposed of as road-base or as filler in asphalt and cement, are still an economic concern mainly because of the large volumes of spent catalysts generated. New processes are being considered to increase the useful life of catalysts or for meeting more stringent disposal requirements for spent catalysts containing metals. This report discusses a collaborative effort between Pacific Northwest National Laboratory (PNNL) and Phillips Petroleum, Inc., to identify promising chemical processes for removing metals adhered to spent hydrodesulfurization (HDS, a type of hydrotreating catalyst) and FCC catalysts. This study, conducted by PNNL, was funded by the US Department of Energy's Bartlesville Project Office. Fresh and spent catalysts were provided by Phillips Petroleum. The FCC catalyst was a rare

  4. The efficient synthesis of a molybdenum carbide catalyst via H2-thermal treatment of a Mo(VI)-hexamethylenetetramine complex.

    Science.gov (United States)

    Wang, Zhi-Qiang; Zhang, Zhong-Biao; Zhang, Ming-Hui

    2011-02-07

    An efficient method for preparation of Mo(2)C catalyst is described, where Mo(2)C is obtained by the heat treatment of a single solid precursor containing (NH(4))(6)Mo(7)O(24) and hexamethylenetetramine (HMT) at 923 K in H(2) flow without conventional prolonged carbonization. The catalysts are characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), BET surface area measurement, and transmission electron microscopy (TEM). Furthermore, these catalysts are evaluated in the dibenzothiophene (DBT) hydrodesulfurization (HDS) reaction, and proved to be superior to those prepared by a temperature-programmed reduction (TPRe) method. The better catalytic performance is ascribed to higher dispersion of Mo(2)C on the support and a lower surface polymeric carbon content. This hydrogen thermal treatment (HTT) method provided a new strategy for the preparation of a highly active molybdenum carbide catalyst.

  5. Ni2P/Al-MCM-41催化剂的制备及其加氢脱硫性能%Preparation and hydrodesulfurization performance of Al-MCM-41 supported nickel phosphide catalysts

    Institute of Scientific and Technical Information of China (English)

    匡志敏; 龚建议; 杨运泉; 王威燕; 陈来福; 贺恒

    2011-01-01

    A1-MCM-41 mesoporous molecular sieves were prepared by the azeotropic distillation and ultrasonic dispersive technology using sodium silicate as silica source , aluminum sulfate as aluminum source and cetyltrimethyl ammonium bromide as structure-directing agent. By using A1-MCM-41 as support, nickel nitrate and diammonium hydrogen phosphate as raw materials, a series of supported Ni2P catalysts on A1-MCM-41 was prepared via the method of temperature-programmed reduction under ultrasonic oscillation. The catalysts were characterized by FT1R, BET, XRD and SEM.Hydrodesulfurization of thiophene catalyzed by Ni2P/Al-MCM-41 was carried out in a high pressure autoclave reactor. The experimental results showed that Al-MCM-41 prepared by ultrasonic dispersive technology had a much higher specific surface area, larger pore volume and pore diameter than that prepared by conventional mechanical mixing. The Al-MCM-41 prepared by azeotropic distillation with ultrasonic dispersive technology was also better than that using only ultrasonic dispersive technology.The Ni2P/A1-MCM-41 catalysts, hydrodesulfurization conversion of thiophene nearly reached 100% at the reaction time 5 h, reaction temperature 548 K, and reaction pressure 3.5 MPa.%以硅酸钠为硅源、硫酸铝为铝源、十六烷基三甲基溴化铵(CTAB)作模板剂,采用共沸蒸馏与超声波分散技术相结合的方法制备了介孔分子筛Al-MCM-41.以Al-MCM-41为载体,硝酸镍和磷酸氢二氨为原料,采用超声波振荡、程序升温还原法制备了Ni2P/Al-MCM-41催化剂,并对Al-MCM-41和Ni2P/Al-MCM-41进行了傅里叶变换红外光谱、比表面积测定、X射线衍射、扫描电镜表征.考察了Ni2P/Al-MCM-41催化剂对噻吩加氢脱硫的催化性能.结果表明:采用超声波制得的Al-MCM-41其比表面积,孔容和孔径明显高于常规搅拌制得的Al-MCM-41,共沸蒸馏制得的Al-MCM-41其比表面积、孔容和孔径高于未共沸蒸馏的Al-MCM-41;

  6. Investigation and development of heavy oil upgrading catalysts. 3

    Energy Technology Data Exchange (ETDEWEB)

    Lee, D.K.; Lee, I.C.; Yoon, W.L.; Lee, H.T.; Chung, H.; Hwang, Y.J.; Park, S.H. [Korea Inst. of Energy Research, Taejon (Korea, Republic of)

    1995-12-01

    This study aimed at the domestic development of HDS catalysts which are most fundamental and wide-used in the petroleum refinery. In this year, some experimental works were conducted for developing the effective utilization technology of the novel dispersed-catalysts in the hydro-desulfurization of heavy oils, and improving the reaction performance of alumina-supported Mo-based hydro-treating catalysts conventionally used in most of refineries. First, it was experimentally proved that the dispersed catalysts of Co-Mo could be employed for the hydro-desulfurization of a heavy atmospheric residual oil excluding the catalyst deactivation. The utilization of a carbon-expanded reactor in combination with this dispersed catalyst system exhibited an enhanced reaction performance and provided an efficient way for the separation and recovery of the dispersed catalytic component from oils. Second, the tungsten-incorporated WCoMo/{gamma}-Al{sub 2}O{sub 3} catalyst revealed the improved catalytic performance in the various hydro-treating reactions and in the initial deactivation rates for the high pressure hydro-treatment of a heavy oil as compared with the commercial CoMo/{gamma}-Al{sub 2}O{sub 3} catalyst. This new experimental finding for the promoting role of the monomeric WO{sub 3} species in CoMo/{gamma}-Al{sub 2}O{sub 3} catalyst may be generally applicable to the Mo-based alumina-sulfide phase, higher catalytic activity, and more extended service life. (author). 101 refs., 33 figs., 18 tabs.

  7. Unraveling the redox behavior of a CoMoS hydrodesulfurization catalyst : A scanning transmission X-ray microscopy study in the tender X-ray range

    NARCIS (Netherlands)

    Al Samarai, Mustafa; Meirer, Florian; Karunakaran, Chithra; Wang, Jian; Vogt, Eelco T C; Zandbergen, Henny W.; Weber, Thomas; Weckhuysen, Bert M.; De Groot, Frank M F

    2015-01-01

    We visualize the elemental zoning in an alumina-supported cobalt molybdenum sulfide (CoMoS) catalyst with scanning transmission X-ray microscopy (STXM). We use the Canadian Light Source beamline 10-ID's (SM) unique combination of soft X-ray and tender X-ray STXM to determine the spatial variation of

  8. Characterization of NiW and CoW Hydrotreating Catalysts

    NARCIS (Netherlands)

    Van der Meer, Y.

    2001-01-01

    While hydrodesulfurization (HDS) is a process that has already been used for over 50 years and has received large attention in the literature, the world-wide trend towards ultra clean fuels has renewed the interest in HDS catalysis research. EU regulations with respect to fuel specifications involve

  9. Egyptian heavy vacuum gas oil hydrotreating over Co-Mo/CNT and Co-Mo/γ-Al2 O3 catalysts

    Institute of Scientific and Technical Information of China (English)

    W Ahmed; Hoda S Ahmed; H S El-Sheshtawy; Nadia A Mohamed; Asmaa I Zahran

    2016-01-01

    The catalytic activity of CoMoS/CNT towards the Egyptian heavy vacuum gas oil hydrotreating was studied. The delivered CNT was functionalized with 6 mol/L HNO3. The CNT were loaded with 12% MoO3(by weight) and 0. 7 Co/Mo atomic ratio with impregnation methods. The γ-Al2 O3 catalyst was also prepared by impregnation method to compare both catalysts activities. The analysis tools such XRD, Raman spectroscopy, TEM, and BET were used to characterize the catalysts. The autoclave reactor was used to operate the hydrotreating experiments. The hydrotreating reactions were tested at various operating conditions of temperature 325-375℃, pressure 2-6 MPa, time 2-6 h, and catalyst/oil ratio (by weight) of 1:75, 1:33 and 1:10. The results revealed that the CoMoS/CNT was highly efficient for the hydrotreating more than the CoMoS/γ-Al2 O3 . Also, the hydrodesulfurization (HDS) increased with increasing catalyst/oil ratio. Additionally, results showed that the optimum condition was temperature 350℃, pressure 4 MPa, catalyst/oil ratio of 1:75 for 2 h. Furthermore, even at low CoMoS/CNT catalyst/oil ratio of 1:75, an acceptable HDS of 77. 1% was achieved.

  10. Soft sensor design for hydrodesulfurization process using support vector regression based on WT and PCA

    Institute of Scientific and Technical Information of China (English)

    Saeid Shokri; Mohammad Taghi Sadeghi; Mahdi Ahmadi Marvast; Shankar Narasimhan

    2015-01-01

    A novel method for developing a reliable data driven soft sensor to improve the prediction accuracy of sulfur content in hydrodesulfurization (HDS) process was proposed. Therefore, an integrated approach using support vector regression (SVR) based on wavelet transform (WT) and principal component analysis (PCA) was used. Experimental data from the HDS setup were employed to validate the proposed model. The results reveal that the integrated WT-PCA with SVR model was able to increase the prediction accuracy of SVR model. Implementation of the proposed model delivers the best satisfactory predicting performance (EAARE=0.058 andR2=0.97) in comparison with SVR. The obtained results indicate that the proposed model is more reliable and more precise than the multiple linear regression (MLR), SVR and PCA-SVR.

  11. 微量杂质对柴油深度加氢脱硫的影响%INFLUENCE OF TRACE IMPURITIES ON DEEP HYDRODESULFURIZATION OF DIESEL

    Institute of Scientific and Technical Information of China (English)

    张锐; 丁石; 刘清河; 牛传峰

    2016-01-01

    从柴油加氢脱硫反应过程中存在的相态出发,在中型加氢试验装置上研究了气相中的CO和原料油中携带的硅等杂质对柴油深度加氢脱硫反应的影响.结果表明:气相中的CO杂质对催化剂的脱硫活性具有抑制作用,随着CO浓度的增大,这种抑制作用加大,但是在其达到一定程度后再继续提高CO浓度,其对加氢脱硫活性的抑制作用基本不变,CO对催化剂活性的抑制是可逆的;液相中携带的含硅化合物会使催化剂中毒,使其加氢脱硫活性大幅降低,影响催化剂的使用周期,当SiO2沉积量为3.31%时,催化剂的加氢脱硫活性损失在10 ℃以上.%The influence of carbon monoxide (CO) in the gas phase and silicon (Si) in the liquid phase on diesel deep hydrodesulfurization was studied.The results show that CO inhibits the HDS performance of catalyst, and with the increase of CO concentration, the inhibition increases and then gradually becomes mild.However, the inhibition of CO is reversible.The Si in liquid phase poisons the catalyst and shortens the catalyst lifetime.It is found that when the SiO2 deposition reaches 3.31%, the activity loss of catalyst is more than 10 ℃.

  12. Effect of catalyst deactivation on vacuum residue hydrocracking

    Directory of Open Access Journals (Sweden)

    Hoda S. Ahmed

    2013-12-01

    Full Text Available Accelerated deactivation tests of the pre-sulfided Mo–W/SiO2–Al2O3 commercial catalyst were performed using heavy vacuum petroleum feedstock. High reaction temperature employed in the accelerated catalyst aging resulted in large amounts of carbonaceous deposition with high aromaticity, which was found to be the principal deactivation cause. The effect of catalyst deactivation on hydrocracking of vacuum residue was studied. Experiments were carried out in a batch reactor at 60 bar, feed to catalyst ratio 10:1 and temperature 425 °C. The duration time for a cycle-run was 4 h. On increasing the interval duration times from 4 to 20 h (i.e. five cycles, the quality of the hydrocracked products was decreased. In each cycle-run, a fresh feedstock was used with the same sulfide catalyst. The quality of distillate products, such as hydrodesulfurization (HDS was decreased from 61.50% to 39.52%, while asphaltene contents of the total liquid product were increased from 2.7% to 5.2% and their boiling ranges were increased during these duration times due to the successive catalyst deactivation during the 5 cycle-runs, caused by successive adsorption of coke formation.

  13. Hydrodesulfurization of light gas oil: Kinetic determination in a batch reactor

    Directory of Open Access Journals (Sweden)

    Skala Dejan U.

    2002-01-01

    Full Text Available The performed investigations were directed toward the analysis of the performance and activity of the fresh and regenerated Cyanamid HDS 20C catalyst in a laboratory batch reactor (2 dm3 for the HDS of the diesel fraction (light gas oil, LGO. Testing of the regenerated catalyst was performed with light gas oil (LGO of different characteristics. The determined values of the reaction rate constant were compared to some published data in the literature for the HDS of specific sulfur compounds as well as the values of the activation energy. The rates of deactivation of the fresh and regenerated catalyst actually existed compared to some other results recently published in the literature. However, such an observed differences were not sufficient to derive a relation which could be used for the determination of the rate of catalyst deactivation.

  14. Insight into thiophene hydrodesulfurization on clean and S-modified MoP(010): a periodic density functional theory study.

    Science.gov (United States)

    Li, Guixia; Zhao, Lianming; Zhu, Houyu; Liu, Xiuping; Ma, Huifang; Yu, Yanchen; Guo, Wenyue

    2017-07-05

    The hydrodesulfurization (HDS) of thiophene on clean and S-modified MoP(010) is investigated to understand the HDS mechanism as well as the surface sulfur (S) atom effect using periodic density functional theory (DFT). The results show that thiophene prefers strongly flat adsorption on both the clean and S-modified surfaces, in either the molecular state or the dissociative state breaking simultaneously one C-S bond, and the adsorption of thiophene can be slightly weakened by the surface S atom. Thermodynamic and kinetic analysis indicates that the HDS of thiophene in both the molecular and dissociative adsorption states prefers to take place along the direct desulfurization (DDS) pathway rather than hydrogenation on both the clean and S-modified MoP(010) surfaces. Surface S shows a promotion effect on the HDS catalytic activity of MoP(010), because the energy barrier/rate constant of the rate-determining step on the DDS pathway is decreased/enlarged under the S modification. Compared with the situation of MoP(001), MoP(010) should have relatively low HDS activity, since a higher energy barrier as well as weaker exothermicity is involved in the reaction on the latter surface.

  15. A 13-week dermal repeat-dose neurotoxicity study of hydrodesulfurized kerosene in rats.

    Science.gov (United States)

    Breglia, Rudolph; Bui, Quang; Burnett, Donald; Koschier, Francis; Lapadula, Elizabeth; Podhasky, Paula; Schreiner, Ceinwen; White, Russell

    2014-01-01

    A 13-week dermal repeat-dose toxicity study was conducted with hydrodesulfurized (HDS) kerosene, a test material that also met the commercial specifications for aviation turbine fuel (jet A). The objectives were to assess the potential for target organ toxicity and neurotoxicity. The HDS kerosene was applied to the shaved backs of Sprague-Dawley CD rats, 12/sex/group, 6 h/d, 5 d/wk in doses of 0 (vehicle control), 165 mg/kg (20% HDS kerosene), 330 mg/kg (40% HDS kerosene), or 495 mg/kg (60% HDS kerosene). Additional rats (12/sex) from the control and the high-dose groups were held without treatment for 4 weeks to assess recovery. Standard parameters of toxicity were investigated during the in-life phase. At necropsy, organs were weighed and selected tissues were processed for microscopic evaluation. Neurobehavioral evaluations included tests of motor activity and functional observations that were conducted pretest, at intervals during the exposure period and after recovery. No test substance-related effects on mortality, clinical observations (except dermal irritation), body weight, or clinical chemistry values were observed. A dose-related increase in skin irritation, confirmed histologically as minimal, was evident at the dosing site. The only statistically significant change considered potentially treatment related was an increase in the neutrophil count in females at 13 weeks. No test article-related effects were observed in the neurobehavioral assessments or gross or microscopic findings in the peripheral or central nervous system tissues in any of the dose groups. Excluding skin irritation, the no observed adverse effect level value for all effects was considered 495 mg/kg/d.

  16. Conversion and reaction kinetics of coke oven gas over a commercial Fe-Mo/Al2O3 catalyst

    Institute of Scientific and Technical Information of China (English)

    屈一新; 徐贺明; 赵见峰; 王志彦; 王亚涛

    2016-01-01

    Producing methanol from coke oven gas (COG) is one of the important applications of COG. Removal of sulfur from COG is a key step of this process. Conversion and reaction kinetics over a commercial Fe−Mo/Al2O3 catalyst (T-202) were studied in a continuous flow fixed bed reactor under pressures of 1.6−2.8 MPa, space time of 1.32−3.55 s and temperatures of 240−360 °C. Though the COG contains about 0.6 mol/mol H2, hydrogenation of CO and CO2 is not significant on this catalyst. The conversions of unsaturated hydrocarbons depend on their molecular structures. Diolefins and alkynes can be completely hydrogenated even at relatively low temperature and pressure. Olefins, in contrast, can only be progressively hydrogenated with increasing temperature and pressure. The hydrodesulfurization (HDS) of CS2 on this catalyst is easy. Complete conversion of CS2 was observed in the whole range of the conditions used in this work. The original COS in the COG can also be easily converted to a low level. However, its complete HDS is difficult due to the relatively high concentration of CO in the COG and due to the limitation of thermodynamics. H2S can react with unsaturated hydrocarbons to form ethyl mercaptan and thiophene, which are then progressively hydrodesulfurized with increasing temperature and pressure. Based on the experimental observations, reaction kinetic models for the conversion of ethylene and sulfur-containing compounds were proposed; the values of the parameters in the models were obtained by regression of the experimental data.

  17. TiO{sub 2} nanotubes supported NiW hydrodesulphurization catalysts: Characterization and activity

    Energy Technology Data Exchange (ETDEWEB)

    Palcheva, R., E-mail: palcheva@gmail.com [Institute of Catalysis, Bulgarian Academy of Sciences, G. Bonchev Str., Bldg. 11, 1113 Sofia (Bulgaria); Dimitrov, L. [Institute of Mineralogy and Crystallography Acad. I. Kostov, G. Bonchev Str., Bldg. 107, 1113 Sofia (Bulgaria); Tyuliev, G.; Spojakina, A. [Institute of Catalysis, Bulgarian Academy of Sciences, G. Bonchev Str., Bldg. 11, 1113 Sofia (Bulgaria); Jiratova, K. [Institute of Chemical Process Fundamentals, Academy of Sciences of the Czech Republic, 165 02 Prague 6 (Czech Republic)

    2013-01-15

    Highlights: Black-Right-Pointing-Pointer NiW catalysts supported on TiO{sub 2} nanotubes, titania and alumina. Black-Right-Pointing-Pointer The best results are obtained with NiW/TiO{sub 2} nanotubes in hydrodesulfurization (HDS) of thiophene. Black-Right-Pointing-Pointer Active phase is Ni-WO{sub x}S{sub y}. Black-Right-Pointing-Pointer Electronic promotion of W by Ti. - Abstract: High surface area TiO{sub 2} nanotubes (Ti-NT) synthesized by alkali hydrothermal method were used as a support for NiW hydrodesulphurization catalyst. Nickel salt of 12-tungstophosphoric acid - Ni{sub 3/2}PW{sub 12}O{sub 40} was applied as oxide precursor of the active components. The catalyst was characterized by S{sub BET}, XRD, UV-vis DRS, Raman spectroscopy, XPS, TPR and HRTEM. The results obtained were compared with those for the NiW catalysts prepared over high surface area titania and alumina supports. A polytungstate phase evidenced by Raman spectroscopy was observed indicating the destruction of the initial heteropolyanion. The catalytic experiments revealed two times higher thiophene conversion on NiW catalyst supported on Ti-NT than those of catalysts supported on alumina and titania. Increased HDS activity of the NiW catalyst supported on Ti-NT could be related to a higher amount of W oxysulfide entities interacting with Ni sulfide particles as consequence of the electronic effects of the Ti-NT observed with XPS analysis.

  18. Study on Residual Oil HDS Process with Mechanism Model and ANN Model

    Institute of Scientific and Technical Information of China (English)

    Ma Chengguo; Weng Huixin

    2009-01-01

    Based on the Residual Oil Hydrodesulfurization Treatment Unit (S-RHT), the n-order reaction kinetic model for residual oil HDS reactions and artificial neural network (ANN) model were developed to determine the sulfur content of hydrogenated residual oil. The established ANN model covered 4 input variables, 1 output variable and 1 hidden layer with 15 neurons. The comparison between the results of two models was listed. The results showed that the predicted mean relative errors of the two models with three different sample data were less than 5% and both the two models had good predictive precision and extrapolative feature for the HDS process. The mean relative error of 5 sets of testing data of the ANN model was 1.62%-3.23%, all of which were smaller than that of the common mechanism model (3.47%-4.13%). It showed that the ANN model was better than the mechanism model both in terms of fitting results and fitting difficulty. The models could be easily applied in practice and could also provide a reference for the further research of residual oil HDS process.

  19. Studies on Characterization of Sulfided Tertiary NiMoP/γ-Al2O3 Catalysts by TPR Technique and Their Thiophene HDS Activity%硫化态三组元NiMoP/γ-Al2O3催化剂的TPR表征及噻吩HDS活性的研究

    Institute of Scientific and Technical Information of China (English)

    齐兴义; 徐春明; 刘植昌; 李文钊; 辛勤

    2001-01-01

    A series of sulfided tertiary NiMoP/γ-Al2O3 catalysts with different contents of MoO3 were prepared by using molybdophosphoric acid of Keggin structure(H3PMo12O40) and nickel nitrate as origins of active phase components of molybdenum, phosphorus and nickel, and characterized by TPR technique, with their HDS activity being investigated with thiophene as a model substrate. For the sulfided Mo-0 catalyst containing no nickel as promoter, the only hydrogen sulfide evolution peak Ⅰ is observed at 462 K and attributed to the hydrogenation of the so-called edge sulfur atoms chemisorbed on coordinatively unsaturated(cus) Mox+ sites on the MoS2 phase(MoS2 slab). With the introduction of nickel into the active phase of the sulfided Mo-0 catalyst and with the increase of the molybdenum loading, a new hydrogen sulfide evolution peak Ⅱ gradually develops at the low temperature side of the peak Ⅰ, at the same time accompanied by both the increase of the area ratio of the peak Ⅱ to the peak Ⅰ and the shift of the hydrogen sulfide evolution maximum rate to lower temperatures, which may imply the existence of two kinds of active centers related to molybdenum and nickel respectively and the synergic action between the two centers above. It should be noted that for the sulfided NiMoP/γ-Al2O3 catalysts, the thiophene HDS rate and the quantity of hydrogen sulfide evolved during TPR process increase monotonously with the atomic ratio of molybdenum to nickel in the form of [n(Ni)+n(Mo)]/n(Ni). On the basis of the results here, the conclusion may be reached that the two kinds of vacancies can be formed on the edge of Ni-Mo-S slab due to the loss of S during TPR process and vacancies or sites related to the H2S evolution peak II should be regarded as the mainly active reaction centers of thiophene HDS.

  20. 4,6-Dimethyl-dibenzothiophene conversion over Al{sub 2}O{sub 3}-TiO{sub 2}-supported noble metal catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Nunez, Sara [Departamento de Ingenieria de Procesos e Hidraulica, Universidad Autonoma Metropolitana-Iztapalapa, San Rafael Atlixco 186, Vicentina, Iztapalapa, 09340, Mexico, D.F. (Mexico); Escobar, Jose, E-mail: jeaguila@imp.mx [Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas 152, San Bartolo Atepehuacan, Gustavo A. Madero, 07730, Mexico, D.F. (Mexico); Vazquez, Armando; Reyes, Jose Antonio de los [Departamento de Ingenieria de Procesos e Hidraulica, Universidad Autonoma Metropolitana-Iztapalapa, San Rafael Atlixco 186, Vicentina, Iztapalapa, 09340, Mexico, D.F. (Mexico); Hernandez-Barrera, Melissa [Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas 152, San Bartolo Atepehuacan, Gustavo A. Madero, 07730, Mexico, D.F. (Mexico)

    2011-03-15

    Research highlights: {yields} Al{sub 2}O{sub 3} and Al{sub 2}O{sub 3}-TiO{sub 2} (molar ratio Al/Ti = 2, AT2) mixed oxides were pore-filling impregnated to obtain Pd, Pt and Pd-Pt catalysts with {approx}1 wt% nominal metal loading. {yields} Reduced catalysts were tested in the 4,6-dimethyl-dibenzothiophene hydrodesulfurization (HDS). {yields} In Pd-containing materials, TiO{sub 2} incorporation into the alumina support was favorable to the catalytic activity of noble metal catalysts. {yields} Enhanced intrinsic activity (per exposed metallic site) was obtained in Pt-containing catalysts supported on the AT2 mixed oxide. {yields} Yield to different products over various catalysts seemed to be strongly influenced by metallic particles dispersion. - Abstract: Al{sub 2}O{sub 3} and Al{sub 2}O{sub 3}-TiO{sub 2} (molar ratio Al/Ti = 2, AT2) mixed oxides were synthesized using a low-temperature sol-gel method and were further pore-filling impregnated to obtain Pd and Pt catalysts with {approx}1 wt% nominal metal loading. Simultaneous impregnation was used to prepare bimetallic materials at Pd:Pt = 80:20. Solids characterization was carried out by N{sub 2}-physisorption, high-resolution transmission electron microscopy (HR-TEM and E-FTEM), X-ray diffraction, temperature-programmed reduction and CO-chemisorption. Reduced (350 deg. C, H{sub 2} flow) catalysts were tested in the 4,6-dimethyl-dibenzothiophene hydrodesulfurization (HDS) (in n-dodecane, at 300 deg. C and 5.5 MPa, batch reactor). In Pd-containing materials, TiO{sub 2} incorporation into the alumina support was favorable to the catalytic activity of noble metal catalysts, where bimetallic Pd-Pt with AT2 carrier had the highest organo-S compound conversion. Enhanced intrinsic activity (per exposed metallic site) was obtained in Pt-containing catalysts supported on the AT2 mixed oxide (as compared to alumina-supported ones). Yield to different products over various catalysts seemed to be strongly influenced by

  1. A review of metal recovery from spent petroleum catalysts and ash.

    Science.gov (United States)

    Akcil, Ata; Vegliò, Francesco; Ferella, Francesco; Okudan, Mediha Demet; Tuncuk, Aysenur

    2015-11-01

    With the increase in environmental awareness, the disposal of any form of hazardous waste has become a great concern for the industrial sector. Spent catalysts contribute to a significant amount of the solid waste generated by the petrochemical and petroleum refining industry. Hydro-cracking and hydrodesulfurization (HDS) catalysts are extensively used in the petroleum refining and petrochemical industries. The catalysts used in the refining processes lose their effectiveness over time. When the activity of catalysts decline below the acceptable level, they are usually regenerated and reused but regeneration is not possible every time. Recycling of some industrial waste containing base metals (such as V, Ni, Co, Mo) is estimated as an economical opportunity in the exploitation of these wastes. Alkali roasted catalysts can be leached in water to get the Mo and V in solution (in which temperature plays an important role during leaching). Several techniques are possible to separate the different metals, among those selective precipitation and solvent extraction are the most used. Pyrometallurgical treatment and bio-hydrometallurgical leaching were also proposed in the scientific literature but up to now they did not have any industrial application. An overview on patented and commercial processes was also presented.

  2. Influence of the sulfidation procedure on the performance and the selectivity of hydro-treating catalysts; Influence de la procedure de sulfuration sur la performance et la selectivite des catalyseurs d'hydrotraitement

    Energy Technology Data Exchange (ETDEWEB)

    Texier, S.

    2004-10-15

    This work is part of a general effort to reduce the sulfur content of fuels to satisfy new European regulations. The objective was to determine the influence of several activating agents during sulfidation on the activity of hydro-desulfurization (HDS) catalysts. Indeed, sulfidation is a critical step to achieve a good level of HDS activity on sulfide catalysts. Under industrial conditions, the activation by organo-sulfide compounds would be more beneficial to obtain active catalysts than the use of hydrogen sulfide. A systematic study of the various operational parameters of the activation process was thus carried out by comparing precisely activation by H{sub 2}S or by organo-sulfides. This study reveals that the recognized advantage of organo-sulfides compounds has not a 'purely chemical origin' but would be more probably related to a heating and/or thermodynamic effect which depends on the processes and on the implementation of sulfidation under the industrial conditions. (author)

  3. Analysis model of structure-HDS

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Presents the model established for Structure-HDS(hydraulic damper system) analysis on the basis of the theoretical analysis model of non-compressed fluid in the round pipe will an uniform velocity used as the basic variable, and pressure losses resulting from cross section changes of fluid route taken into consideration. Which provides necessary basis for researches on earthquake responses of a structure with a spacious first story, equipped with HDS at first floor.

  4. Characterization of the active site structure of Pd and Pd-promoted Mo sulfide catalysts by means of XAFS.

    Science.gov (United States)

    Kubota, T; Okamoto, Y

    2001-03-01

    Recently, noble metal catalysts are noted as promising candidates for new super-deep-hydrodesulfurization (HDS) catalysts. In this study, we investigated the structure of Pd particles supported on zeolite and Al2O3 under a sulfidation or reduction condition. From EXAFS analysis, it was found for sulfided Pd catalysts that small Pd sulfide clusters are formed without sintering. It was also revealed that no extensive growth of metal Pd particles occurs in Pd/NaY sulfide catalysts even after a treatment with H2 at 673 K. The dispersion of Pd metal particles is improved by H2/H2S treatment. These results indicate that in the presence of H2S, Pd shows high resistance against particle growth. A comparison of the Mo and Pd K-edge EXAFS spectra for MoS(x)/Pd-NaY and Pd-NaY catalysts revealed the existence of Mo-Pd bondings by the addition of Mo sulfide, indicating a direct interaction between Mo and Pd sulfides.

  5. Vibrational Spectroscopic Studies of Hydrogen, Carbon-Monoxide and Thiophene Adsorption on Ruthenium-Sulfide and Sulfided Ruthenium Catalysts.

    Science.gov (United States)

    Heise, William Herbert

    The "working surface" of ruthenium hydrodesulfurization (HDS) catalysts has been modeled by preadsorption of sulfur, carbon and carbon plus sulfur on Ru(0001). Adsorption and decomposition of thiophene over these surfaces have been investigated using TDS/TPRS, XPS and EELS. Thiophene is proposed to decompose via a three-step mechanism involving: (i) initial thiophene cracking at 120 K yielding surface sulfur and hydrocarbon species, (ii) hydrogen desorption near 230 K providing additional decomposition ensembles and (iii) continued decomposition to form "metallocycle -like" intermediates which retain EELS features similar to thiophene. Preadsorbed carbon or carbon plus sulfur are not as effective for passivation of the surface toward metallocycle formation as preadsorbed sulfur alone. This result is attributed to the fact that carbon deposited from butadiene annealed and decomposed at 700 K forms islands, while sulfur establishes a well-ordered superlattice on the surface. The decrease in metallocycle formation with increasing poison levels appears to explain HDS selectivity and specific activity trends observed in our laboratory from mildly sulfided (10% H_2S/H_2 , 673 K, 2h) ruthenium catalysts retaining submonolayers of sulfur. Incoherent inelastic neutron scattering (IINS) has been used to characterize hydrogen adsorption sites on ruthenium sulfide. Hydrogen resides on sulfur anions to form SH groups, yielding two non-degenerate bending modes at 600 and 710 cm^{-1}. Complementary hydrogen adsorption and H_2/D _2 exchange data suggest that the active sites for hydrogen adsorption may be coordinatively unsaturated S-S anion pairs. Comparison of CO adsorption on sulfided Ru/Al _2O_3 to sulfur precovered Ru(0001) reveals an adsorption site related to edge/corner atoms directly perturbed by sulfur, consistent with previous kinetic studies demonstrating higher specific activity for thiophene HDS over smaller ruthenium crystallites.

  6. Modeling and simulation of hydrodemetallation and hydrodesulfurization processes with transient catalytic efficiency

    Directory of Open Access Journals (Sweden)

    E.M. Matos

    2000-06-01

    Full Text Available A model is presented for the description of the concentration behavior of organometallic and sulfurated compounds in hydrodemetallation and hydrodesulfurization catalytic processes, where catalyst effectiveness decreases with time. Due to the complexity of the mixture, an approach based on pseudocomponents was adopted. The system is modeled as an isothermal tubular reactor with axial dispersion, where the gas phase (hydrogen in excess flows upward concurrently with the liquid phase (heavy oil while the solid phase (catalyst stays inside the reactor in an expanded (confined bed regime. The catalyst particles are very small and are assumed to be uniformly distributed in the reactor. The heavy oil fractions contain organometallics and sulfurated compounds, from which the metals and sulfur are to be removed, the metals as deposits in the catalyst pores and the sulfur as gas products. Simulations were carried out where the concentration profile inside the reactor was calculated for several residence times.

  7. 螯合剂对Co-Mo/Al2 O3成型加氢脱硫催化剂性能的影响%Effect of the chelating agent on the hydrodesulfurization activity of extruded Co-Mo/Al2 O3 catalysts

    Institute of Scientific and Technical Information of China (English)

    柳来栓; 裴甜婕; 安文平; 李裕; 李楠

    2014-01-01

    以拟薄水铝石为原料,添加有机溶剂,经挤条成型、干煅、焙烧制备了比表面积大、孔分布宽的柱状γ-Al2 O3载体;采用共浸渍法制备了系列Co-Mo/Al2 O3催化剂( CoO和MoO3质量分数分别为2%和8%)。利用低温氮吸附、XRD和H2-TPR技术对催化剂进行了表征,考察了螯合剂柠檬酸( CA)、草酸( OA)和乙二胺四乙酸( EDTA)对成型催化剂粗苯加氢脱硫活性的影响。结果表明,添加螯合剂后,催化剂的前驱体主要沉积在载体的3~10 nm中孔内,活性组分以无定形态高度分散在载体上。添加CA可提高催化剂的还原性,显著降低Mo6+的还原温度。在300℃、3.0 MPa、液体空速( LHSV)为2 h-1和氢油体积比为600的条件下,噻吩硫的脱除率可达到99.9%以上。%γ-Al2 O3 monolith support with high surface area and wide pore size distribution was obtained by extruding the mixture of pseudo boehmite and organic additives, as well as subsequent drying and calculation;a series of Co-Mo catalysts with ca. 8% molybdenum and 2% cobalt were prepared through co-impregnation of the support with solutions of ammonium heptamolybdate, cobalt nitrate and the chelating agent of citric acid ( CA) , oxalic acid ( OA ) and ethylenediamine tetraacetic acid ( EDTA ) . The Co-Mo/Al2 O3 catalysts were characterized by nitrogen sorption, XRD and H2-TPR; the effect of chelating agents on their textural properties and activity in hydrodesulphurisation ( HDS ) of a commercial crude benzol was investigated. The results indicated that the catalyst precursors were mostly deposited over the surface of the mesopores with a diameter between 3 and 10 nm; the addition of chelating agent results in a high dispersion of Co-Mo species on the alumina support. The H2-TPR results revealed that the addition of CA is able to improve the catalyst reducibility and shift the reduction temperature of Mo6+to lower temperature. For the HDS reaction of the real-feedstock in a

  8. Preparation and Hydrodesulfurization Performance of Ni-B Amorphous Alloy Catalyst Supported by APTS Modified SBA-15%APTS改性SBA-15负载Ni-B非晶态合金催化剂的制备及加氢脱硫性能

    Institute of Scientific and Technical Information of China (English)

    谌伟庆; 黄勇; 石秋杰

    2012-01-01

    SBA-15 was modified by APTS with covalent grafting method,and then Ni-B amorphous alloy catalysts were prepared by using APTS modified SBA-15 and unmodified SBA-15 as supports.The catalytic activities of both catalysts were characterized,and thiophene hydrodesulfurization was selected as probe reaction.The results show that thiophene conversation of Ni-B/SBA-15-APTS is 50.8%,which is higher than the one of Ni-B/SBA-15.The complexation between NH2 and Ni2+ would be benefit for dispersion of Ni-B alloy particles and reduction of Ni2+.According to ICP results,Ni-B/SBA-15-APTS show bigger quantity of Ni in support and higher content of Ni in Ni-B amorphous alloy than Ni-B/SBA-15,resulting in the higher activity.%采用共价接枝法制备APTS改性介孔分子筛SBA-15,将氨基官能团接枝到SBA-15表面.并采用化学还原法制备了Ni-B/SBA-15-APTS非晶态合金催化剂,以噻吩加氢脱硫为探针反应,研究了其催化加氢脱硫性能.结果表明,240℃时,APTS改性SBA-15所负载的Ni-B催化剂噻吩转化率达到50.8%,较未改性SBA-15所负载的催化剂噻吩转化率有显著地提高.由于氨基与Ni2+的配合作用,有助于Ni在催化剂中的分散,因而更容易被还原.ICP结果表明,在相同的制备条件下,相比未改性的SBA-15,APTS改性SBA-15使其催化剂中Ni的负载量增加,并且非晶态合金组成中Ni的含量也增大,B的含量降低,有利于提高催化剂的活性.

  9. Highly active sulfided CoMo catalysts supported on (ZrO{sub 2}–TiO{sub 2})/Al{sub 2}O{sub 3} ternary oxides

    Energy Technology Data Exchange (ETDEWEB)

    Escobar, José, E-mail: jeaguila@imp.mx [Instituto Mexicano del Petróleo, Eje Central Lázaro Cárdenas 152, Col. San Bartolo Atepehuacan, Gustavo A. Madero, México, D.F. 07730 (Mexico); De Los Reyes, José A., E-mail: jarh@xanum.uam.mx [Area de Ing. Química, UAM – Iztapalapa, San Rafael Atlixco 186, Col. Vicentina, Iztapalapa, México, D.F. 09340 (Mexico); Ulín, Carlos A. [Area de Ing. Química, UAM – Iztapalapa, San Rafael Atlixco 186, Col. Vicentina, Iztapalapa, México, D.F. 09340 (Mexico); Barrera, María C., E-mail: mcbdgavilan@gmail.com [Facultad de Ciencias Químicas, Universidad Veracruzana, Av. Universidad km. 7.5, Col. Santa Isabel, Coatzacoalcos, Veracruz, México, D.F. 96538 (Mexico)

    2013-12-16

    (ZrO{sub 2}–TiO{sub 2})/Al{sub 2}O{sub 3} ternary oxide at 20 mol% Al{sub 2}O{sub 3} (80% ZrO{sub 2}–TiO{sub 2}, in turn at 40–60 mol ratio) prepared by controlled co-precipitation (by urea thermal decomposition) of zirconium (ZrOCl{sub 2}·8H{sub 2}O) and titanium (TiCl{sub 4}) chlorides over a ground alumina substrate constitutes a promising material to be used as carrier of sulfided hydrodesulfurization (HDS) catalysts. After calcining (at 500 °C), the ternary oxide presented textural properties (S{sub g} = 387 m{sup 2} g{sup −1}, V{sub p} = 0.74 ml g{sup −1}, mean pore diameter = 7.6 nm) suitable to its utilization as carrier of catalysts applied in the oil-derived middle distillates HDS. As determined by temperature programmed-reduction and Raman and UV–vis spectroscopies ZrO{sub 2}–TiO{sub 2} deposition over alumina substrate resulted in decreased proportion of Mo{sup 6+} species in tetrahedral coordination on the oxidic impregnated material. As those species constitute hardly reducible precursors, their diminished concentration could be reflected in enhanced amount of Mo species susceptible of activation by sulfiding (H{sub 2}S/H{sub 2} at 400 °C) over our ternary carrier. Limiting the concentration of zirconia-titania (at 40–60 mol ratio) to 20 mol% in the mixed oxides support allowed the preparation of highly active promoted (by cobalt, at Co/(Co + Mo) = 0.3) MoS{sub 2} phase (at 2.8 atoms/nm{sup 2}), that formulation showing excellent properties in hydrodesulfurization (HDS) of both dibenzothiophene and highly-refractory 4,6-dimethyl-dibenzothiophene. Due to alike yields to various HDS products over CoMo/(ZrO{sub 2}–TiO{sub 2})/Al{sub 2}O{sub 3} and the corresponding Al{sub 2}O{sub 3}-supported formulation, presence of similar actives sites over those catalysts was strongly suggested. It seemed that enhanced concentration of octahedral Mo{sup 6+} over the oxidic impregnated precursor with (ZrO{sub 2}–TiO{sub 2})/Al{sub 2}O{sub 3

  10. Session 4: HDS, HDN and HYD assisted by ultrasound using formic acid as hydrogen precursor

    Energy Technology Data Exchange (ETDEWEB)

    Scott Carlos, E.; Bolivar, C.; Grobas, J. [Universidad Central de Venezuela, Centro de Catalisis Petroleo y Petroquimica, Escuela de Quimica, Facultad de Ciencias, Caracas (Venezuela)

    2004-07-01

    The study of chemical effects of ultrasound is a rapidly growing research area, and its use in heavy crude oil upgrading has been explored. In this work, hydrogenation of cyclohexene and biphenyl, hydrodesulfurization of benzothiophene and hydro-denitrogenation of quinoline, in the presence of a hydrogen precursor, a Pd/C catalyst and ultrasound irradiation was studied. It was found, that the use of formic acid as hydrogen precursor in presence of ultrasonic irradiation was an effective system to promote hydrogenation of cyclohexene (98%) and biphenyl (21%), desulfurization of benzothiophene (18%) and hydrogenation of quinoline (19%), at very mild conditions, i.e. ambient temperature and pressure. (authors)

  11. Synthesis of high-surface-area Co-O-Si complex oxide for skeletal isomerization of 1-hexene and hydrodesulfurization of thiophene%高表面积复合氧化物Co-O-Si的制备及其催化1-己烯骨架异构和噻吩加氢脱硫活性

    Institute of Scientific and Technical Information of China (English)

    赵鹬; 王俊恩; 陈慧; 张晓艳; 傅玉川; 沈俭一

    2014-01-01

    通过硝酸钴与硅酸钠共沉淀、辅以正丁醇干燥技术制备了具有原子分散度的Co-O-Si复合氧化物(Co/Si原子比≈0.65),该催化剂具有较大的比表面积(562 m2/g)和较强表面酸性.在硫化处理后,能够形成高度分散的硫化物活性组分,在模型汽油加氢处理反应中显示了较高的催化活性,在573 K时,噻吩的加氢脱硫活性可达99.4%,同时,1-己烯的骨架异构收率达到了35%.该催化剂虽然不含Mo,其加氢脱硫活性可与工业催化剂Co-Mo/γ-Al2O3相当.而在汽油深度加氢脱硫过程中,直链烯烃往往被加氢饱和,造成辛烷值损失.该催化剂则可使部分直链烯烃发生骨架异构而生成异构烷烃,可减少深度加氢脱硫过程中的辛烷值损失.%The coprecipitation of sodium silicate with cobalt nitrate, combined with an n-butanol drying pro-cess, led to the formation of a Co-O-Si complex oxide (Co/Si atomic ratio≈0.65) with atomically dispersed Co and Si atoms. The complex oxide had a high surface area (562 m2/g) and strong sur-face acidity. Sulfidation resulted in the formation of highly dispersed cobalt sulfide, which had high activity in the hydrodesulfurization (HDS) of thiophene (99.4%) and skeletal isomerization of 1-hexene (35%) at 573 K. The HDS activity was as high as that of the industrial catalyst Co-Mo/γ-Al2O3, although no Mo was present. The material could therefore be used for the skeletal isomerization of linear olefins during deep HDS of gasoline to reduce octane number loss caused by olefin saturation.

  12. Fabrication of hollow spheres by dry-gel conversion and its application in the selective hydrodesulfurization of FCC gasoline.

    Science.gov (United States)

    Zhang, Jinchang; Wang, Gang; Jin, Fengying; Fang, Xiangchen; Song, Chunshan; Guo, Xinwen

    2013-04-15

    Hollow spheres were synthesized from MCM-41 solid spheres by dry-gel conversion. It was found that water amount has a major impact on the formation of hollow spheres. Transmission electron microscopy (TEM) images revealed that the hollow spheres are between 500 and 600 nm in size with a dense shell of ca. 100 nm. The synthesized hollow sphere sample was examined as a support for hydrodesulfurization catalyst. The sulfur removal was enhanced while olefin hydrogenation of FCC gasoline was suppressed, and thus, the octane value was preserved when the hollow spheres (Na type) were loaded with Ni and Mo oxides as catalyst.

  13. Integrating principal component analysis and vector quantization with support vector regression for sulfur content prediction in HDS process

    Directory of Open Access Journals (Sweden)

    Shokri Saeid

    2015-01-01

    Full Text Available An accurate prediction of sulfur content is very important for the proper operation and product quality control in hydrodesulfurization (HDS process. For this purpose, a reliable data- driven soft sensors utilizing Support Vector Regression (SVR was developed and the effects of integrating Vector Quantization (VQ with Principle Component Analysis (PCA were studied on the assessment of this soft sensor. First, in pre-processing step the PCA and VQ techniques were used to reduce dimensions of the original input datasets. Then, the compressed datasets were used as input variables for the SVR model. Experimental data from the HDS setup were employed to validate the proposed integrated model. The integration of VQ/PCA techniques with SVR model was able to increase the prediction accuracy of SVR. The obtained results show that integrated technique (VQ-SVR was better than (PCA-SVR in prediction accuracy. Also, VQ decreased the sum of the training and test time of SVR model in comparison with PCA. For further evaluation, the performance of VQ-SVR model was also compared to that of SVR. The obtained results indicated that VQ-SVR model delivered the best satisfactory predicting performance (AARE= 0.0668 and R2= 0.995 in comparison with investigated models.

  14. Evaluation of nebulised hay dust suspensions (HDS) for the diagnosis and investigation of heaves. 1: Preparation and composition of HDS.

    Science.gov (United States)

    Pirie, R S; McLachlan, G; McGorum, B C

    2002-07-01

    Currently, heaves is investigated by exposing susceptible horses to dusty hay. Consequently, the response will be dependent on the organic dust content and composition of the hay. It was hypothesised that the use of a hay dust suspension (HDS) would reduce the variability of the challenge and therefore standardise experimental protocols. Furthermore, analysis of HDS would also permit further investigation of the organic dust components responsible for the response. Three hay dust suspensions (HDS-1, 2 and 3) were prepared for use in the diagnosis and investigation of heaves. HDS were produced from fine dust particles, comprising mostly fungal spores, collected from 3 batches of dusty hay. HDS-1 and 3 were analysed for endotoxin, beta-D-glucan and protein concentrations, general protease activity and enumeration and size distribution of particulates. Protease activity was mainly attributable to a 28 kDa serine protease and to 85 kDa and 160 kDa metalloproteases. The particulate and soluble components of HDS could be aerosolised by jet nebulisation. We therefore conclude that detailed analysis of HDS is possible, that such a challenge system provides a method of standardising experimental protocols and that all components of HDS (both soluble and particulate) can be delivered to the lung using standard nebulisation techniques. For the above reasons, nebulised HDS offers considerable advantages over conventional hay/straw challenge for the diagnosis and investigation of heaves.

  15. Comparison of Tungsten and Molybdenum Carbide Catalysts for the Hydrodeoxygenation of Oleic Acid

    NARCIS (Netherlands)

    Hollak, S.A.W.; Gosselink, R.J.A.; Es, van D.S.; Bitter, J.H.

    2013-01-01

    Group 6 (W, Mo) metal carbide catalysts are promising alternatives to hydrodesulfurization (NiMo, CoMo) catalysts and group 10 (Pd) type catalysts in the deoxygenation of vegetable fats/oils. Herein, we report a comparison of carbon nanofiber-supported W2C and Mo2C catalysts on activity, selectivity

  16. Selective Hydrodesulfurization of FCC Gasoline Using LH-07 Catalyst

    Institute of Scientific and Technical Information of China (English)

    Da Jianwen; Han Xinzhu; Liu Aihua; Xu Xinzhong

    2002-01-01

    @@ 1.Introduction Since the environmental regulations are increasingly strin gent than ever, the production of clean automobile fuel is a vital target in China, especially after China has become a WTO member. However, the sulfur content in gasoline pool of China is still very high. Over 95% of the sulfur in gaso line pool comes from FCC naphtha. It is necessary to remove sulfur in FCC naphtha.

  17. A catalytic distillation process for light gas oil hydrodesulfurization

    Energy Technology Data Exchange (ETDEWEB)

    Vargas-Villamil, F.D.; Marroquin, J.O.; Paz, C. de la; Rodriguez, E. [Prog. de Matematicas Aplicadas y Computacion, Prog. de Tratamiento de Crudo Maya, Instituto Mexicano del Petroleo, Mexico City, DF (Mexico)

    2004-07-01

    A light gas oil hydrodesulfurization process via catalytic distillation is developed and compared to a conventional process. By integrating the separation and reaction into a single unit, the catalytic distillation may produce a diesel with low concentration of sulfur compounds at a lower cost than the traditional reaction/separation process. The process proposed in this work is compared to an optimised conventional hydrodesulfurization unit which represents fairly well a plant that belongs to the National System of Refineries. During the optimisation of the conventional process, a compromise is established among the production of diesel and naphtha and the operating costs. The results show that the light gas oil hydrodesulfurization via catalytic distillation is as or more efficient than the conventional process. However, the removal of the sulfur compounds is carried out under less rigorous conditions. This design reduces the fix and operational costs. (author)

  18. Molybdenum sulfide/carbide catalysts

    Science.gov (United States)

    Alonso, Gabriel; Chianelli, Russell R.; Fuentes, Sergio; Torres, Brenda

    2007-05-29

    The present invention provides methods of synthesizing molybdenum disulfide (MoS.sub.2) and carbon-containing molybdenum disulfide (MoS.sub.2-xC.sub.x) catalysts that exhibit improved catalytic activity for hydrotreating reactions involving hydrodesulfurization, hydrodenitrogenation, and hydrogenation. The present invention also concerns the resulting catalysts. Furthermore, the invention concerns the promotion of these catalysts with Co, Ni, Fe, and/or Ru sulfides to create catalysts with greater activity, for hydrotreating reactions, than conventional catalysts such as cobalt molybdate on alumina support.

  19. Sensitivity analysis of a light gas oil deep hydrodesulfurization process via catalytic distillation

    Energy Technology Data Exchange (ETDEWEB)

    Rosales-Quintero, A.; Vargas-Villamil, F.D. [Prog. de Matematicas Aplicadas y Computacion, Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas 152, Mexico, D.F. 07330 (Mexico); Arce-Medina, E. [Instituto Politecnico Nacional, ESIQIE, Ed. 8 Col. Lindavista, Mexico, D.F. 07738 (Mexico)

    2008-01-30

    In this work, a sensitivity analysis of a light gas oil deep hydrodesulfurization catalytic distillation column is presented. The aim is to evaluate the effects of various parameters and operating conditions on the organic sulfur compound elimination by using a realistic light gas oil fraction. The hydrocarbons are modeled using pseudocompounds, while the organic sulfur compounds are modeled using model compounds, i.e., dibenzothiophene (DBT) and 4,6-dimethyl dibenzothiophene (4,6-DMDBT). These are among the most refractive sulfur compounds present in the oil fractions. A sensitivity analysis is discussed for the reflux ratio, bottom flow rate, condenser temperature, hydrogen and gas oil feed stages, catalyst loading, the reactive, stripping, and rectifying stages, feed disturbances, and multiple feeds. The results give insight into the qualitative effect of some of the operating variables and disturbances on organic sulfur elimination. In addition, they show that special attention must be given to the bottom flow rate and LGO feed rate control. (author)

  20. Evaluation of nebulised hay dust suspensions (HDS) for the diagnosis and investigation of heaves. 3: Effect of fractionation of HDS.

    Science.gov (United States)

    Pirie, R S; Dixon, P M; McGorum, B C

    2002-07-01

    To investigate the relative importance of inhaled particulates and soluble components in the response to inhaled hay dust suspension (HDS), heaves (previously termed chronic obstructive pulmonary disease; n = 7) and control (n = 6) horses were given inhalation challenges with whole and fractionated HDS. Fractionation was achieved by centrifugation to yield supernatant (SUP) and particulate debris. The particulates were then washed repeatedly in saline to produce a washed particulate (WP) fraction which comprised mainly fungal spores, and a wash fraction (WF) which comprised saline and soluble components washed from the surface of the particulates. Inhalation of HDS and SUP induced a significant airway neutrophilia in both groups, with the magnitude of the response being significantly greater in heaves horses. SUP induced significantly less airway neutrophilia than HDS in both groups, despite the endotoxin and protease content of HDS and SUP being comparable. WP and WF induced only a slight airway neutrophilia in heaves horses. However, a combined challenge with SUP and WP induced a neutrophilic response approaching the magnitude of that following HDS challenge, indicating that dust particulates contribute to the pulmonary recruitment of neutrophils in heaves. Consequently, inhalation challenge with HDS, which contains both particulates and soluble dust components, may be a more useful tool for the diagnosis and investigation of heaves than aqueous dust extracts, which contain only soluble components.

  1. Derivation of elastic stiffness formula for leaf type HDS and conceptual design of leaf type HDS of SMART FA

    Energy Technology Data Exchange (ETDEWEB)

    Song, Kee Nam; Kang, Heung Seok; Yoon, Kyung Ho; Suh, Jung Min; Lee, Jin Seok

    1997-12-01

    Based on the strain energy method and Euler beam theory, an elastic stiffness formula for the leaf type HDS, now widely used as the holddown spring for the FA of Westinghouse type PWRs, has been derived. Through comparisons with the characteristic test results of the test produced HDSs, it has been found that the derived formula is useful to reliably estimate an elastic stiffness with material properties and the geometric data of an HDS. Through sensitivity analysis of HDS`s elastic stiffness, the elastic stiffness sensitivity with respect to different design variables was identified, as well as the design variables having remarkable sensitivity. In addition, finite element analysis using surface-to-surface contact elements on the contact surface between the leaves shows that the analysis results are in good agreement with the elastic stiffness determined from the derived formula. It is therefore expected that the finite element model and the analysis method will be useful in the analysis of the elasto-plastic behavior of the leaf type HDS in the future. To both reduce the cobalt content, which is considered to be the source of radioactive contamination in the reactor core, and to design the HDS to meet the holddown requirements of the SMART FA, a conceptual design for the HDS of the SMART FA has been performed through two analyses of the elastic characteristics of the HDS : the possibility of substitution of the leaf spring`s material from Inconel 718 to Zircaloy and the effects on the HDS`s elastic characteristics according to the variation of leaf thickness and the number of leaves composing the HDS. (author). 34 refs., 33 tabs., 37 figs.

  2. Catalyst design for clean and efficient fuels

    DEFF Research Database (Denmark)

    Šaric, Manuel

    of synthesizing dimethyl carbonate electrochemically. Hydrodesulfurization is an industrial refining process in which sulfur is removed from oil in order to reduce SO2 emissions. The study on hydrodesulfurization involves determining the active sites and their atomic scale structure for the industrially used...... is to identify which sites are active towards specific molecules and in getting insight to what the ideal catalyst should look like in terms of morphology. Dimethyl carbonate is an environmentally benign compound that can be used as a solvent and precursor in chemical synthesis or as a fuel and fuel additive...

  3. Evaluation of nebulised hay dust suspensions (HDS) for the diagnosis and investigation of heaves. 2: Effects of inhaled HDS on control and heaves horses.

    Science.gov (United States)

    Pirie, R S; Collie, D D S; Dixon, P M; McGorum, B C

    2002-07-01

    To evaluate inhaled hay dust suspensions (HDS) as a tool for the diagnosis and investigation of heaves, the pulmonary inflammatory and functional consequences of inhalation challenge with 3 different HDS were determined in 6 control and 7 asymptomatic heaves horses. Heaves horses given HDS challenge developed the characteristic features of heaves, including airway neutrophilia, obstructive airway dysfunction and mucus hypersecretion. While HDS challenge induced a mild airway neutrophilia in controls, the no-response threshold for controls was greater than that of heaves horses, and there was no overlap in BALF neutrophil ratio of controls and heaves horses. Furthermore, HDS challenge did not induce airway dysfunction or mucus hypersecretion in controls. Therefore, HDS challenges enabled differentiation of control and heaves horses. Interestingly, in both groups, the airway neutrophilia was a dose-dependent response rather than an 'all or nothing' response. This study suggests that HDS challenges are of value in the diagnosis and investigation of heaves.

  4. INHIBITION EFFECTS OF QUINOLINE, INDOLE AND CARBAZOLE ON HDS OF 4,6-DMDBT OVER Ni-Mo CATALYST%喹啉、吲哚和咔唑对Ni-Mo催化剂上4,6-DMDBT HDS反应抑制作用

    Institute of Scientific and Technical Information of China (English)

    韩姝娜; 周同娜; 柴永明; 周红军; 刘晨光

    2010-01-01

    使用Ni-Mo催化剂,在固定床微型反应器上进行喹咻、吲哚和咔唑存在下的4,6-二甲基二苯并噻吩(4,6-DMDBT)加氢脱硫(HDS)反应.结果表明,含氮化合物对4,6-DMDBT HDS有强烈的抑制作用.这3种氮化物的抑制作用大小顺序是:喹啉、咔唑和吲哚.氮化物对于HDS 2条反应路径均有抑制作用,但是抑制的程度不同.喹啉对先加氢再脱硫(HYD)反应路径的影响比对直接脱硫(DDS)反应路径的强烈得多;吲哚存在下HYD反应为主要的HDS反应;咔唑对2条反应路径的抑制程度相似,使4,6-DMDBT HDS的HYD和DDS反应比例与不添加氮化物时相似.氮化物含量增加使4,6-DMDBT HDS中DDS反应比例增加.

  5. Fabrication of three-dimensional MoS2-graphene hybrid monoliths and their catalytic performance for hydrodesulfurization%3D二硫化钼/石墨烯组装体的制备及其催化脱硫性能

    Institute of Scientific and Technical Information of China (English)

    王旭珍; 刘宁; 胡涵; 王新平; 邱介山

    2014-01-01

    A simple process to synthesize three-dimensional molybdenum disulfide-graphene monolithic catalysts (3D-MoS2-G) was developed. 3D-MoS2-G hybrid monoliths were fabricated by a combined hydrothermal self-assembly and freeze-drying treat-ment, in which ammonium tetrathiomolybdate and graphite oxide were used as starting materials. The structure and morphology of the samples were characterized by X-ray diffraction, Fourier transform infrared spectrometry, Raman spectrometry, field emission scanning electron microscopy, transmission electron microscopy and nitrogen adsorption. The catalytic performance of the hybrid monoliths was investigated by evaluating the activity for the hydrodesulfurization ( HDS) of carbonyl sulfide ( COS) . In addition, the influence of microwave irradiation on the catalytic property of the 3D-MoS2-G monoliths was also investigated. It is demonstra-ted that after microwave irradiation the 3D-MoS2-G monoliths show an excellent activity for COS hydrogenation compared with the traditional MoS2/γ-Al2 O3 catalyst prepared by impregnation-sulfidation. The 3D-MoS2-G-160M monolith hydrothermally synthe-sized at 160℃ exhibits the highest COS conversion of 100% at a relatively low temperature (260℃) for the HDS reaction. The su-perior performance of the 3D-MoS2-G-160M catalyst can be ascribed to the unique hybridized structure of the MoS2 nanoparticles u-niformly dispersed on graphene sheets in the monolith.%采用水热合成法,原位一步还原硫钼酸铵/氧化石墨前驱体,得到三维的二硫化钼/石墨烯(3D-MoS2/G)组装体催化剂。通过X-射线衍射仪、傅里叶变换红外光谱仪、拉曼光谱仪、场发射扫描电镜、透射电镜以及低温氮吸附等手段对其结构和形貌进行表征。以羰基硫( COS)的催化加氢转化为评价指标,对比研究微波处理前/后组装体催化剂的加氢脱硫性能。与传统硫化法制备的MoS2/γ-Al2 O3催化剂相比,经微波处理的水热一步法构筑的3

  6. Novel, high-activity hydroprocessing catalysts: Iron group phosphides

    Science.gov (United States)

    Wang, Xianqin

    A series of iron, cobalt and nickel transition metal phosphides was synthesized by means of temperature-programmed reduction (TPR) of the corresponding phosphates. The same materials, Fe2P, CoP and NO, were also prepared on a silica (SiO2) support. The phase purity of these catalysts was established by x-ray diffraction (XRD), and the surface properties were determined by N2 BET specific surface area (Sg) measurements and CO chemisorption. The activities of the silica-supported catalysts were tested in a three-phase trickle bed reactor for the simultaneous hydrodenitrogenation (HDN) of quinoline and hydrodesulfurization (HDS) of dibenzothiophene using a model liquid feed at realistic conditions (30 atm, 370°C). The reactivity studies showed that the nickel phosphide (Ni2P/SiO2) was the most active of the catalysts. Compared with a commercial Ni-Mo-S/gamma-Al 2O3 catalyst at the same conditions, Ni2P/silica had a substantially higher HDS activity (100% vs. 76%) and HDN activity (82% vs. 38%). Because of their good hydrotreating activity, an extensive study of the preparation of silica supported nickel phosphides, Ni2P/SiO 2, was carried out. The parameters investigated were the phosphorus content and the weight loading of the active phase. The most active composition was found to have a starting synthesis Ni/P ratio close to 1/2, and the best loading of this sample on silica was observed to be 18 wt.%. Extended x-ray absorption fine structure (EXAFS) and x-ray absorption near edge spectroscopy (XANES) measurements were employed to determine the structures of the supported samples. The main phase before and after reaction was found to be Ni2P, but some sulfur was found to be retained after reaction. A comprehensive scrutiny of the HDN reaction mechanism was also made over the Ni2P/SiO2 sample (Ni/P = 1/2) by comparing the HDN activity of a series of piperidine derivatives of different structure. It was found that piperidine adsorption involved an alpha-H activation

  7. Kinetic Study on Liquid-Phase Hydrodesulfurization of FCC Diesel in Tubular Reactors

    Institute of Scientific and Technical Information of China (English)

    Li Hua; Yang Jinliang; Weng Huixin; Wang Jiming

    2015-01-01

    According to the characteristics of FCC diesel, a technology of liquid-phase hydrodesulfurization of the diesel in tubular reactors was proposed and lab-scale experiments were carried out. A kinetic model for the hydrodesulfurization pro-cess was developed and veriifed. The model was utilized to predict the sulfur content of products under different operating conditions. The effects of temperature, space velocity, pressure, and hydrogen concentration on the desulfurization rate were investigated.

  8. Development and Commercial Application of Third Generation Resid Hydrotreating Catalysts

    Institute of Scientific and Technical Information of China (English)

    Hu Dawei; Yang Qinghe; Dai Lishun; Zhao Xinqiang

    2013-01-01

    Based on the mechanism of resid hydrotreating reaction by coordinating the catalyst activity and stability, the diffusion mechanism and catalyst reactivity, the cost and catalyst performance, and the production and application re-quirements, the third-generation series catalysts for residue hydrotreating have been developed by Research Institute of Petroleum Processing, SINOPEC. The new series RHT catalysts possess higher activity for HDS, HDM and HDCCR per-formance as well as longer run length. The commercial results for application of these catalysts have demonstrated that the new catalyst system performs better than the reference ones.

  9. EFFECTS OF CATALYST MORPHOLOGY ON HYDROTREATING REACTIONS

    Directory of Open Access Journals (Sweden)

    TYE CHING THIAN

    2008-08-01

    Full Text Available Due to the new environmental regulations for fuel quality, refineries need to process cleaner fuel. This requires an improvement in performance of hydrotreating catalysts. Improvements in catalyst activity require knowledge of the relationships between catalyst morphology and activity. Molybdenum sulfide, the generally agreed catalysts that give the best performance in hydrocracking and hydrotreating was investigated for its morphology effects on hydrotreating reactions. Three types of MoS2 catalysts with different morphology were studied. They are crystalline MoS2, exfoliated MoS2 and MoS2 derived from a precursor, molybdenum naphthenate. Exfoliated MoS2 with minimal long range order, with much higher rim edges has shown relative higher hydrogenation activity. Generally, results of MoS2 catalyst activities in hydrogenation, hydrodesulfurization, hydrodenitrogenation and hydrideoxy¬gena¬tion are in agreement with the rim-edge model.

  10. Commercial Application of OCT-M Technology for Selective Hydrodesulfurization of Gasoline

    Institute of Scientific and Technical Information of China (English)

    Yi Xiqing; Li Bin; Xiao Fengliang; Zhao Leping

    2006-01-01

    This article analyzed the problems arising from retrofitting the 800 kt/a virgin diesel hydrofining unit into a 1.0 Mt/a OCT-M gasoline HDS unit at the refinery of Luoyang Petrochemical Company, and the optimized measures aimed at improvements in operation of HDS unit. The preliminary calibration results have indicated the high desulfurization rate and good selectivity of the HDS technology to fulfill the demand of Luoyang Petrochemical Company for product quality upgrading with the targets of technical revamp fully implemented.

  11. The development, validity and reliability of the Hospital in the Home Dependency Scale (HDS).

    Science.gov (United States)

    Santamaria, N; Daly, S; Addicott, R; Clayton, L

    2001-01-01

    The aim of this study was to develop and investigate the validity and reliability of the Hospital-in-the-Home (HITH) Dependency Scale (HDS). The HDS is a new instrument designed to measure the dependency of HITH patients. It calculates an overall dependency level by rating four dimensions of the provision of HITH nursing care. Specifically, these dimensions are the complexity of assessment, complexity of treatment, time taken to provide the treatment, and the frequency of treatment. The results of testing the HDS suggest that it is valid in measuring adult medical and surgical HITH patient dependency. The scale demonstrated strong stability over time in test retest procedures over a one month period (r = 0.80, p HDS is a valid, reliable instrument that is quick and easy to use in the HITH setting.

  12. Novel MoO2/carbon hierarchical nano/microcomposites: synthesis, characterization, solid state transformations and thiophene HDS activity.

    Science.gov (United States)

    Avendaño, Carlos; Briceño, Alexander; Méndez, Franklin J; Brito, Joaquín L; González, Gema; Cañizales, Edgar; Atencio, Reinaldo; Dieudonné, Philippe

    2013-02-28

    Novel MoO(2)/C nano/microcomposites were prepared via a bottom-up approach by hydrothermal carbonization of a solution of glucose as a carbon precursor in the presence of polyoxometalates (POMs: phosphomolybdic acid [H(3)PMo(12)O(40)] and ammonium heptamolybdate tetrahydrate [(NH(4))(6)Mo(7)O(24)]·4H(2)O). The structural characterization by FT-IR, XRPD, SEM and TEM analyses revealed the controlled formation of hierarchical MoO(2)/C composites with different morphologies: strawberry-like, based on carbon microspheres decorated with MoO(2) nanoparticles; MoO(2)/C core-shell composites; and irregular aggregates in combination with ring-like microstructures bearing amorphous Mo species. These composites can be fine-tuned by varying reaction time, glucose/POM ratio and type of POM precursor. Subsequent transformations in the solid state through calcinations of MoO(2)/C core-shell composites in air lead to hollow nanostructured molybdenum trioxide microspheres together with nanorods and plate microcrystals or cauliflower-like composites (MoO(2)/C). In addition, the MoO(2)/C composite undergoes a morphology evolution to urchin-like composites when it is calcined under nitrogen atmosphere (MoO(2)/C-N(2)). The MoO(2)/C strawberry-like and MoO(2)/C-N(2) composites were transformed into Mo carbide and nitride supported on carbon microspheres (Mo(2)C/C, MoN/C, and MoN/C-N(2)). These phases were tested as precursors in thiophene hydrodesulphurization (HDS) at 400 °C, observing the following trend in relation to the thiophene steady-state conversion: MoN/C-N(2) > MoN/C > Mo(2)C/C > MoO(2)/C-N(2) > MoO(2)/C. According to these conversion values, a direct correlation was observed between higher HDS activity and decreasing crystal size as estimated from the Scherrer equation. These results suggest that such composites represent interesting and promising precursors for HDS catalysts, where the activity and stability can be modified either by chemical or structural changes of the

  13. Studies on Characterization of Active Sites of Sulfided PtMo/γ-Al2O3 Catalysts by Using Low Temperature FTIR Spectroscopy of Adsorbed CO and Their Thiophene HDS Activity%硫化态PtMo/γ-Al2O3催化剂活性位的低温CO-FTIR方法表征及噻吩HDS活性的研究

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    目前, 负载型钼(钨)基双组元过渡金属硫化物[Co(Ni)Mo(W)/γ-Al2O3]被广泛应用于石油馏分油的加氢脱硫(HDS)和加氢脱氮(HDN)反应过程[1~3]. 许多研究结果表明, 硫化态Co(Ni)Mo(W)/γ-Al2O3催化剂的活性相组元钴(镍)、钼(钨)及硫形成具有二维六方点阵结构的Co(Ni)-Mo(W)-S相(slab). 其中钴(镍)和钼(钨)的主要催化功能依次是活化H2和锚定杂原子有机底物[3~5].

  14. [Cloning and prokaryotic expression analysis of HDS from Salvia miltiorrhiza bge.f.alba].

    Science.gov (United States)

    Jiang, Dan; Rong, Qi-Xian; Yuan, Qing-Jun; Zhang, Wen-Jing; Zhang, Yong-Qing; Huang, Lu-Qi

    2014-11-01

    According to the designed specific primers of gene fragment based on the Salvia miltiorrhiza transcriptome data, with the method of reverse transcription polymerase chain reaction (RT-PCR), this study cloned full-length cDNA sequence of 1-hydroxy-2-methyl-2-(E)-butenyl-4-diphosphate synthase gene from Salvia miltiorrhiza bge.f.alba, this sequence is named as SmHDS and its GenBank registration number is KJ746807. SmHDS, 2 529 bp long, contains an ORF of 2 229 bp, encodes 742 amino acids, including 5' UTR 170 bp and 3' UTR 130 bp. Using bioinformatics software, having made a homology analysis of the obtained sequence, we can have a conclusion that SmHDS have a close genetic relationship with HDS of Salvia miltiorrhiza. Analysis result of prokaryotic expression revealed that in Escherichia coli, SmHDS expressed target proteins which in size are comparable with the protein predicted. Meanwhile, the 4 factors which can influence the protein expression were optimized, the 4 factors are inducing temperature, inducing time, IPTG concentrations and density of inducing host bacterium (A600). The optimal expression conditions of SmHDS were 30 degrees C until the A600 is 0.6, and add IPTG to a final concentration of 0.2 mmol x L(-1), and the induction time of 20 h. It provides theoretical basis for the further study of the function of 1-hydroxy-2-methyl-2-(E)-butenyl-4-diphosphate synthase in the biosynthesis of tanshinone compounds.

  15. XAFS characterization of industrial catalysts: in situ study of phase transformation of nickel sulfide

    Science.gov (United States)

    Wang, J.; Jia, Z.; Wang, Q.; Zhao, S.; Xu, Z.; Yang, W.; Frenkel, A. I.

    2016-05-01

    The online sulfiding process for nickel-contained catalyst often ends up with a nickel sulfide mixture in refinery plant. To elucidate the local environment of nickel and its corresponding sulfur species, a model catalyst (nickel sulfide) and model thermal process were employed to explore the possibilities for characterization of real catalysts in industrial conditions. The present investigation shows effectiveness of in situ XANES and EXAFS measurements for studying the phase stability and phase composition in these systems, which could be used to simulate real sulfiding process in industrial reactions, such as hydrodesulfurizations of oil.

  16. KINETIKA HIDRODESULFURISASI DIBENZOTHIOPHENE (HDS DBT MENGGUNAKAN KATALIS NiMo/γ-Al2O3

    Directory of Open Access Journals (Sweden)

    Subagjo Subagjo

    2014-12-01

    Full Text Available Evaluasi kinetika reaksi hidrodesulfurisasi (HDS dibenzothiophene dan simulasi nafta hydrotreater yang berada di PT. PERTAMINA Refinery Unit II Dumai menggunakan katalis NiMo/Al2O3 hasil pengembangan telah dilakukan. Kinetika reaksi HDS DBT dilakukan dalan sistem reaktor batch dengan variasi temperatur 280-320oC dan tekanan 30 bar. Data kinetika diolah dengan persamaan hukum pangkat (law power dan persamaan kinetik mekanistik (Langmuir Hinshelwood, LH. Berdasarkan model hukum pangkat, kinetika HDS DBT menggunakan NiMo/Al2O3 hasil pengembangan merupakan  orde satu  terhadap DBT dengan konstanta Arhenius  sebesar 165633 detik-1 dan energi aktivasi 69017 J/mol (16,56 kkal/mol. Model LH yang cocok untuk reaksi HDS DBT menggunakan NiMo/Al2O3 hasil pengembangan adalah model LH yang mengilustrasikan adanya kompetisi antara reaktan DBT dan H2 pada tipe pusat aktif yang sama, dengan DBT teradsorb secara kuat sedangkan H2 teradsorpsi secara lemah. Energi aktifasi dan konstanta Arhenius berdasarkan model LH ini ini berturut-turut adalah 81409 J/mol (19,34 kkal/mol dan 1658133 s-1. Dengan menggunakan persamaan laju reaksi hukum pangkat, model memberikan hasil konversi sulfur yang sama dengan hasil keluaran reaktor nafta hydrotreater RU II-Dumai, yaitu mencapai 98%.

  17. A simpler and more accurate AUTO-HDS framework for clustering and visualization of biological data.

    Science.gov (United States)

    Campello, Ricardo J G B; Moulavi, Davoud; Sander, Jörg

    2012-01-01

    In [1], the authors proposed a framework for automated clustering and visualization of biological data sets named AUTO-HDS. This letter is intended to complement that framework by showing that it is possible to get rid of a user-defined parameter in a way that the clustering stage can be implemented more accurately while having reduced computational complexity.

  18. Investigation into the use of cement kiln dust in high density sludge (HDS) treatment of acid mine water.

    Science.gov (United States)

    Mackie, Allison L; Walsh, Margaret E

    2015-11-15

    The purpose of this study was to investigate the potential to replace lime with cement kiln dust (CKD) in high density sludge (HDS) treatment of acid mine drainage (AMD). The bench-scale study used two water samples: AMD sampled from a lead-zinc mine with high concentrations of iron (Fe), zinc (Zn), and arsenic (As) (Fe/Zn-AMD) and a synthetic AMD solution (Syn-AMD) spiked with ferric sulfate (Fe2(SO4)3). Arsenic was found to be significantly reduced with CKD-HDS treatment of Fe/Zn-AMD compared to lime-HDS treatment, to concentrations below the stringent mine effluent discharge regulation of 0.10 mg As/L (i.e., 0.04 ± 0.02 mg/L). Both CKD- and lime-HDS treatment of the two AMD samples resulted in settled water Fe concentrations above the stringent discharge guideline of 0.3 mg Fe/L. CKD addition in the HDS process also resulted in high settled water turbidity, above typical discharge guidelines of 15 mg TSS/L. CKD-HDS treatment was found to result in significantly improved settled solids (i.e., sludge) quality compared to that generated in the lime-HDS process. HDS treatment with CKD resulted in 25-88% lower sludge volume indices, 2 to 9 times higher % wet solids, and 10 to 20 times higher % dry solids compared to lime addition. XRD and XPS testing indicated that CKD-HDS sludge consisted of mainly CaCO3 and SiO2 with Fe(3+) precipitates attached at particle surfaces. XRD and XPS testing of the lime-HDS generated sludge showed that it consisted of non-crystalline Fe oxides typical of sludge formed from precipitates with a high water concentration. Increased sedimentation rates were also found for CKD (1.3 cm/s) compared to lime (0.3 cm/s). The increased solids loading with CKD addition compared to lime addition in the HDS process was suggested to both promote surface complexation of metal precipitates with insoluble CKD particles and increase compression effects during Type IV sedimentation. These mechanisms collectively contributed to the reduced water content of

  19. HDS-R在广东沿海农村老年期痴呆筛查中的应用%Application of HDS-R in Screening Senile Dementia in Coastal Rural Areas of Guangdong Province

    Institute of Scientific and Technical Information of China (English)

    沐楠; 陆泳; 冯容妹; 方少心; 周伟成; 江美娟

    2000-01-01

    目的:探讨HDS-R在老年期痴呆筛查中的应用及其影响因素.方法:本研究用改良长谷川痴呆量表(HDS-R)对广东沿海三个县中1018名世居农村,年龄≥65岁的老年人进行痴呆筛查.结果:HDS-R分为0-32.5分,平均23.50±5.80分,经逐步回归分析表明年龄、教育程度、痴呆诊断、听力、性别是影响HDS-R评分的重要因素;HDS-R界限分为17分时,敏感度95.1%,特异度为97.7%.结论:年龄、教育程度、痴呆诊断、听力、性别是影响HDS-R评分的重要因素,HDS-R因其特异度和敏感度高且易于实施、项目简便,适合在我国使用.

  20. Synthesis of carbon nanotubes by CCVD of natural gas using hydrotreating catalysts

    Directory of Open Access Journals (Sweden)

    Ahmed E. Awadallah

    2012-12-01

    Full Text Available Carbon nanotubes have been successfully synthesized using the catalytic chemical vapor deposition (CCVD technique over typical refining hydrotreating catalysts (hydrodesulfurization and hydrodenitrogenation containing Ni–Mo and Co–Mo supported on Al2O3 catalysts at 700°C in a fixed bed horizontal reactor using natural gas as a carbon source. The catalysts and the as-grown CNTs were characterized by transmission electron microscopy, HRTEM, X-ray diffraction patterns, EDX and TGA–DTG. The obtained data clarified that the Ni–Mo catalyst gives higher yield, higher purity and selectivity for CNTs compared to Co–Mo catalyst. XRD, TEM and TGA reveal also that the Ni–Mo catalyst produces mostly CNTs with different diameters whereas the Co–Mo catalyst produces largely amorphous carbon.

  1. Kinetics of hydrodesulfurization of dimethyldibenzothiophenes in a gas oil narrow-cut fraction and solvent effects

    Energy Technology Data Exchange (ETDEWEB)

    Laredo, Georgina C.; Cortes, Carlos M. [Programa de Tratamiento de Crudo Maya, Instituto Mexicano del Petroleo, Eje Central LazaroCardenas 152, Col. San Bartolo Atepehuacan, D.F. 07730 Mexico City (Mexico)

    2003-10-15

    The hydrodesulfurization kinetics of the dimethyldibenzothiophenes lump (DMDBTs) presented in a narrow-cut gas oil fraction at conditions commonly used in the hydrotreating of diesel feedstocks, has been experimentally determined. In order to obtain experimental data at different DMDBTs concentrations, octadecane was used as a solvent. During the mathematical treatment of the data, an inhibiting matrix effect due to the sulfur compounds themselves and octadecane was observed. These inhibitory effects were quantitatively represented by introducing the apparent adsorption constants K{sub D}[D] and K{sub sol}[S]{sup 2} into the denominator of a modified Langmuir-Hinshelwood type rate equation.

  2. Characterization of 1-hydroxy-2-methyl-2-(E)-butenyl-4-diphosphate synthase (HDS) gene from Ginkgo biloba.

    Science.gov (United States)

    Kim, Sang-Min; Kim, Soo-Un

    2010-02-01

    Diterpene trilactone ginkgolides, one of the major constituents of Ginkgo biloba extract, have shown interesting bioactivities including platelet-activating factor antagonistic activity. 1-Hydroxy-2-methyl-2-(E)-butenyl-4-diphosphate synthase (HDS), converting 2-C-methyl-d-erythritol-2,4-cyclodiphosphate into 1-hydroxy-2-methyl-2-(E)-butenyl-4-diphosphate, is the penultimate enzyme of the seven-step 2-C-methyl-d-erythritol 4-phosphate pathway that supplies building blocks for plant isoprenoids of plastid origin such as ginkgolides and carotenoids. Here, we report on the isolation and characterization of the full-length cDNA encoding HDS (GbHDS, GenBank accession number: DQ251630) from G. biloba. Full-length cDNA of GbHDS, 2,763 bp long, contained an ORF of 2,226 bp encoding a protein composed of 741 amino acids. The theoretical molecular weight and pI of the deduced mature GbHDS of 679 amino acid residues are 75.6 kDa and 5.5, respectively. From 2 weeks after initiation of the culture onward, transcription level of this gene in the ginkgo embryo roots increased to about two times higher than that in the leaves. GbHDS was predicted to possess chloroplast transit peptide of 62 amino acid residues, suggesting its putative localization in the plastids. The transient gene expression in Arabidopsis protoplasts confirmed that the transit peptide was capable of delivering the GbHDS protein from the cytosol into the chloroplasts. The isolation and characterization of GbHDS gene enabled us to further understand the role of GbHDS in the terpenoid biosynthesis in G. biloba.

  3. Hydrotreating of waste lube oil by rejuvenated spent hydrotreating catalyst

    Directory of Open Access Journals (Sweden)

    Sadeek A. Sadeek

    2014-03-01

    Full Text Available Large quantities of catalysts are used in the Egyptian refining industry for the purification and upgrading of various petroleum streams. These catalysts gradually lose activity through deactivation with time and the spent catalysts were usually discarded as solid waste. On the other hand, waste lube oil contains heavy metals coming from undergirded base oil and additives, these metals have carcinogenic effect and cause serious environmental problems. Studies are conducted on the reclamation of metals, rejuvenation and reuse of the spent hydrotreating catalyst (Mo–Ni/Al which have been used in re-refining of waste lube oil at Alexandria Petroleum Company. Three leaching solvents were used: oxidized oxalic acid, benzoic acid and boric acid at different concentrations (4%, 8% and 16%, different oxidizing agents (H2O2 and Fe(NO33 and different modes of addition of oxidizing agents (batch and continuous. The results indicated that 4% oxalic acid + 5% Fe(NO33 at continuous addition of oxidizing agents was the most efficient leaching solvent to facilitate metal removal and rejuvenate catalyst. The fresh catalyst was applied for re-refining of waste lube oil under different reaction temperatures (320–410 °C in order to compare the hydrodesulphurization (HDS activity with both the fresh, treated and spent catalysts. The results indicated that the rejuvenation techniques introduce a catalyst have HDS activity nearly approach to that the fresh of the same type.

  4. PROGRESS IN CATALYST AND PROCESS DEVELOPMENT FOR LOW SULFUR AND LOW AROMATICS DIESEL PRODUCTION

    Institute of Scientific and Technical Information of China (English)

    ZHOUYong; HANChong-ren

    2003-01-01

    The article includes three parts:①The development and performance of FH-DS catalyst for deep and ultra -deep distillate HDS;②The single stage HDS/HDA hydrotreating process for the production of low sulfur and low aromatics diesels from straight run and coker AGO by using highly active base metal catalyst at moderate pressure;③A two-stage aromatics saturation system utilizing noble metal catalyst in the second stage developed for production of low sulfur and low aromatics diesel from LCO.FDA catalyst developed by FRIPP has high activity for aromatics saturation together with high tolerance for sulfur and nitrogen in the feed.The process is effective in reducing density and increasing cetane number.

  5. Diverse expression patterns of LIM-homeodomain transcription factors (LIM-HDs) in mammalian inner ear development.

    Science.gov (United States)

    Huang, Mingqian; Sage, Cyrille; Li, Huawei; Xiang, Mengquig; Heller, Stefan; Chen, Zheng-Yi

    2008-11-01

    LIM-homeodomain transcription factors (LIM-HDs) are essential in tissue patterning and differentiation. But their expression patterns in the inner ear are largely unknown. Here we report on a study of twelve LIM-HDs, by their tempo-spatial patterns that imply distinct yet overlapping roles, in the developing mouse inner ear. Expression of Lmx1a and Isl1 begins in the otocyst stage, with Lmx1a exclusively in the non-sensory and Isl1 in the prosensory epithelia. The second wave of expression at E12.5 includes Lhx3, 5, 9, Isl2, and Lmx1b in the differentiating sensory epithelia with cellular specificities. With the exception of Lmx1a and Lhx3, all LIM-HDs are expressed in ganglion neurons. Expression of multiple LIM-HDs within a cell type suggests their redundant function.

  6. 高浓度泥浆法(HDS)-铁盐处理工业污酸废水半工业试验%Pilot-plant Test of Acid Waste Water Treatment by High Density Slurry(HDS) Ferrous Salt Process

    Institute of Scientific and Technical Information of China (English)

    宋文涛

    2011-01-01

    对高浓度泥浆(HDS)-铁盐法处理冶炼企业污酸工业废水进行半工业试验.结果表明,在pH=10条件下,HDS出水的Pb、Zn均可达到国家排放标准,As出水控制在10 mg/L以下,再经后续铁盐除砷工序,As排放也可达到国家排放标准.HDS产生底泥固含可达27%左右,显著高于石灰法的水平(2%以下).%The semi-industrial experiment for acid waste water treatment in nonferrous smelter was conducted via High Density Slurry (HDS)-ferrous salt process. The results indicate that, both Pb and Zn could meet the requirement of the national emission standards through the HDS-ferrous salt process at pHIO as concentration in HDS system effluent could be controlled to less than 10 mg/L. The solid content in HDS sludge is up to 27%, which is significantly higher than that in LDS sludge(<2%).

  7. Novel bimetallic dispersed catalysts for temperature-programmed coal liquefaction. Technical progress report, October 1995--December 1995

    Energy Technology Data Exchange (ETDEWEB)

    Song, C.; Cooke, W.S.; Schmidt, E.; Schobert, H.H.

    1996-02-01

    Coal liquefaction involves cleavage of methylene, dimethylene and ether bridges connecting polycyclic aromatic units and the reactions of various oxygen functional groups. Here in this quarterly, we report on the catalytic effects of several molybdenum-, cobalt-, and iron-containing compounds in the reactions of dibenzothiophene (DBT) with hydrogen under conditions related to coal liquefaction. The catalytic effects of several molybdenum-, cobalt-, and iron-containing compounds have been examined in the hydrogenation and hydrodesulfurization reactions of dibenzothiophene (DBT) under conditions related to coal liquefaction. The metal compounds are candidate catalyst precursors for direct coal liquefaction. The reactions were carried out in batch microautoclave reactors at 400{degrees}C for 30 minutes with 6.9 MPa (cold) hydrogen pressure, and tridecane solvent. A metal loading of 0.5 mol% resulted in low conversion and only hydrogenation. Addition of sulfur in 4:1 molar ratio led only to a minor increase in conversion and hydrodesulfurization. The use of a higher boiling solvent (octadecane vs. tridecane) was beneficial in providing increased conversion, hydrodesulfurization, and hydrogenation. An increase in metal compound loading to 36.2 mol% led to a dramatic increase in conversion, hydrodesulfurization, and hydrocracking. Molybdenum hexacarbonyl at 36 mol% loading, with added sulfur at 6:1 ratio and octadecane solvent, gave 100% conversion of dibenzothiophene to other products with 100% hydrodesulfurization. Ammonium tetrathiomolybdate and molybdenum(III) chloride are less active under similar conditions. A cobalt-molybdenum thiocubane complex gave unexpectedly low conversions. Iron and cobalt carbonyls also provided very low conversions, even with added sulfur.

  8. A study of peptide vaccine HDS from Streptococcus mutans glucosyltransferase- the synthesis and appraisement of peptide HDS%人工合成多肽防龋疫苗HDS的研究--Ⅰ多肽HDS序列合成和鉴定

    Institute of Scientific and Technical Information of China (English)

    丁芸; 凌均棨; 陈罕

    2003-01-01

    目的:人工合成变形链球菌葡糖基转移酶第549~567位多肽序列HDS.方法:应用固相多肽合成仪合成变形链球菌葡糖基转移酶上549~567位氨基酸序列HDS,使用基质辅助激光解吸电离飞行时间质谱法碎片结构分析技术,对合成产物进行检测.结果:准确合成了19个氨基酸的多肽序列HDS,纯度达97%.结论:成功合成变形链球菌葡糖基转移酶多肽片断为多肽防龋疫苗研究提供了基础.

  9. 包装工业用纸干增强剂HDS-5的制备和应用%The Preparation and Application of HDS-5 as The Reinforcer of The Wrapping Paper

    Institute of Scientific and Technical Information of China (English)

    贺贤璋; 朱艳

    2008-01-01

    研究了具有核壳结构聚合物干增强剂HDS-5的制备工艺、使用性能,以及HDS-5单独使用和与淀粉混用,通过表面施胶提高纸干强度的应用工艺.并验证了两者混用有很好的增强效果和协同效应.

  10. 包装工业用纸干增强剂HDS-5的制备和应用%The Preparation and Application of HDS- 5 As the Reinforcer of the Wrapping Paper

    Institute of Scientific and Technical Information of China (English)

    贺贤璋; 朱艳

    2006-01-01

    研究了具有核壳结构聚合物干增强剂HDS-5的制备工艺、使用性能,以及HDS-5单独使用和与淀粉混用,通过表面施胶提高纸干强度的应用工艺,并验证了两者混用有很好的增强效果和协同效应.

  11. The Preparation and Application of HDS-4B as the Dry Strength Additive of Industrial Paper%工业技术用纸干增强剂HDS-4B的制备及应用

    Institute of Scientific and Technical Information of China (English)

    贺贤璋; 朱艳

    2005-01-01

    研究了通过水溶液高分子聚合和接枝反应制备干增强剂HDS-4B的制备工艺,以及HDS-4B与聚酰胺环氧氯丙烷类湿强剂配合使用提高纸和纸板的干湿强度应用工艺,并验证了两者有很好的增强效果和协同效应.

  12. Confirmation of transiting Neptunes from HATNet and HATSouth using Keck/HIRES and Subaru/HDS

    Science.gov (United States)

    Bakos, Gaspar; Hartman, Joel D.; Bayliss, Daniel; Jordan, Andres; Sato, Bun'ei

    2014-02-01

    Wide-field photometric observations by the HATNet and HATSouth projects have identified ~ 1700 candidate transiting exoplanets (TEPs) around moderately bright stars (V ⪉ 14), leading to the publication of 49 TEPs, with many more confirmed planets undergoing analysis. Among the objects that we have identified are nine promising candidate transiting Neptunes. Only a handful of well- characterized Neptunes are known, and fewer still are known around bright stars, so it is imperative to confirm and characterize these candidates. Here we are proposing for 2 nights each on Keck/HIRES and Subaru/HDS (4 nights altogether) to confirm 6 of these candidate Neptunes. These are around moderately bright stars (V ≲ 13) and most have prior follow-up observations, including moderately high- precision RVs which place upper limits on the RV semiamplitudes ruling out hot Jupiters. If confirmed, these planets would represent a substantial increase in the number of well characterized Neptune-size planets with masses and radii measured to better than ~ 20% precision, and orbiting stars bright enough to permit further follow-up. We note that the HATSouth project is an equal collaboration between researchers in the US, Chile and Australia. For the Subaru/HDS component of this proposal, we request that the time allocation be split evenly between the NOAO, Chilean and Australian Gemini TACs.

  13. Influence of Si/Al Ratio on Catalytic Performance of (Co)Mo/Saponite Catalysts

    OpenAIRE

    Koningsberger, D.C.; Leliveld, R.G.; Ros, T.G.; van Dillen, A.J.; Geus, John W.

    1999-01-01

    The influence of the Si/Al ratio of the support of (Co)Mo/saponite catalysts on the performance in the hydrodesulfurisation of thiophene and hydrocracking of n-decane has been studied. The initial thiophene HDS activity of the sulfided Co catalysts increased with increasing support acidity, while with the CoMo catalysts the opposite effect was observed. The large drop in activity at lower Si/Al ratios is ascribed to the occurrence of two separate cobalt and molybdenum sulfide phases instead o...

  14. Stimulation of Water Injection Wells by Using Swelled Clay Shrinkage Agent HDS-01%缩膨剂HDS-01及其缩膨降压增注技术

    Institute of Scientific and Technical Information of China (English)

    张学锋

    2004-01-01

    研制了一种不仅能防止粘土水化膨胀,还能使已水化膨胀粘土颗粒体积收缩的阳离子聚合物即缩膨剂HDS-01,用于中原卫城、马寨油田水敏储层注水井的减压增注处理.介绍了该剂的缩膨机理.以现用防膨剂SSN-13(一种聚季铵盐)为对比剂,考察了HDS-01的应用性能:HDS-01和SSN-13的缩膨率分别为81.5%~86.2%和17.2%~18.5%;防膨率分别为84.5%~86.2%和81.5%~83.2%;储层水敏岩心在HDS-01和SSN-13溶液中的失重率分别为<7%和>60%;充填砂柱经HDS-01和SSN-13溶液处理后,冲刷出的微粒量分别为空白实验值的1.25%~2.60%和96.4%~121.9%,最终渗透率分别为初始值的98.6%~118%和12%~52%;常规酸化后岩心注水压力迅速回升到原值,缩膨处理后则稳定下降,长时间内回升趋势很小.现场使用的HDS-01溶液浓度5%~15%,处理半径1.5~2.0 m.介绍了在38口注水井进行HDS-01缩膨处理的结果:注水压力下降,注水量上升,有效期超过132天,许多对应油井增产.图4表3.

  15. Oxidation catalyst

    Science.gov (United States)

    Ceyer, Sylvia T.; Lahr, David L.

    2010-11-09

    The present invention generally relates to catalyst systems and methods for oxidation of carbon monoxide. The invention involves catalyst compositions which may be advantageously altered by, for example, modification of the catalyst surface to enhance catalyst performance. Catalyst systems of the present invention may be capable of performing the oxidation of carbon monoxide at relatively lower temperatures (e.g., 200 K and below) and at relatively higher reaction rates than known catalysts. Additionally, catalyst systems disclosed herein may be substantially lower in cost than current commercial catalysts. Such catalyst systems may be useful in, for example, catalytic converters, fuel cells, sensors, and the like.

  16. High dispersion spectroscopy of solar-type superflare stars with Subaru/HDS

    CERN Document Server

    Notsu, Yuta; Maehara, Hiroyuki; Notsu, Shota; Shibayama, Takuya; Nogami, Daisaku; Shibata, Kazunari

    2015-01-01

    We carried out spectroscopic observations with Subaru/HDS of 50 solar-type superflare stars found from Kepler data. More than half (34 stars) of the target stars show no evidence of the binary system, and we confirmed atmospheric parameters of these stars are roughly in the range of solar-type stars. We then conducted the detailed analyses for these 34 stars. First, the value of the "$v\\sin i$" (projected rotational velocity) measured from spectroscopic results is consistent with the rotational velocity estimated from the brightness variation. Second, there is a correlation between the amplitude of the brightness variation and the intensity of Ca II IR triplet line. All the targets expected to have large starspots because of their large amplitude of the brightness variation show high chromospheric activities compared with the Sun. These results support that the brightness variation of superflare stars is explained by the rotation of a star with large starspots.

  17. The Haptic Deictic System-HDS: Bringing Blind Students to Mainstream Classrooms.

    Science.gov (United States)

    Oliveira, Francisco C M B; Quek, F; Cowan, H; Bing Fang

    2012-01-01

    Mathematics instruction and discourse typically involve two modes of communication: speech and graphical presentation. For the communication to remain situated, dynamic synchrony must be maintained between the speech and dynamic focus in the graphics. In sighted people, vision is used for two purposes: access to graphical material and awareness of embodied behavior. This embodiment awareness keeps communication situated with visual material and speech. Our goal is to assist students who are blind or visually impaired (SBVI) in the access to such instruction/communication. We employ the typical approach of sensory replacement for the missing visual sense. Haptic fingertip reading can replace visual material. We want to make the SBVI aware of the deictic gestures performed by the teacher over the graphic in conjunction with speech. We employ a haptic glove interface to facilitate this embodiment awareness. We address issues from the conception through the design and implementation to the effective and successful use of our Haptic Deictic System (HDS) in inclusive classrooms.

  18. Crystal growth, Judd–Ofelt analysis and radiative properties of Nd:YAG single crystal grown by HDS

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Huaixin, E-mail: guohuaixin@gmail.com; Zhang, Mingfu, E-mail: mfzhang1@hit.edu.cn; Han, Jiecai; Nie, Ying

    2013-08-15

    Nd{sup 3+}-doped Y{sub 3}A{sub l5}O{sub 12} single crystal was successfully grown by horizontal directional solidification (HDS) method; in addition optical absorption and fluorescence spectra were measured at room temperature. Base on the Judd–Ofelt theory, the intensity parameters of Nd{sup 3+} in YAG crystal grown by HDS were determined, and then three spectroscopic parameter Ω{sub t} (t=2,4,6), radiative transition probabilities, radiative lifetime and branching ratios were obtained according to the absorption spectra and fluorescence spectra, and the results were discussed as well. Furthermore, the stimulated emission cross-section of {sup 4}F{sub 3/2}–{sup 4}I{sub 11/2} transition of Nd{sup 3+} in YAG crystal grown by the HDS technique was calculated as 17.86×10{sup −20} cm{sup 2}. In comparison with Nd:YAG crystal grown by the Czochraiski technique, those results indicated that lowly Nd{sup 3+}-doped YAG crystal grown by HDS method had highly efficient stimulated emission for laser materials. -- Highlights: ► The intensity parameters of Nd{sup 3+} in YAG crystal grown by the HDS were determined base on the Judd–Ofelt theory. ► The spectroscopic quality factor Ω{sub 4}/Ω{sub 6} was stimulated to be 0.6497. ► Radiative transition probabilities, radiative lifetime and branching ratios were estimated. ► The emission cross-section calculated for the {sup 4}F{sub 3/2}→{sup 4}I{sub 11/2} transition was 17.86×10{sup −20} cm{sup 2}.

  19. Hydrotreating of used oil; Prediction of industrial trickle-bed operation from pilot-plant data

    Energy Technology Data Exchange (ETDEWEB)

    Skala, D.U.; Saban, M.D.; Orlovie, M. (Belgrade Univ. (Yugoslavia). Tehnolosko-Metalurski Fakultet); Meyn, V.W.; Severin, D.K.; Rahimian, I.G.H. (German Inst. for Petroleum Research, 3392 Clausthal-Zellerfeld (DE)); Marjanovic, M.V. (Refinery Beograd, Pancevacki put 83, 11001 Beograd (YU))

    1991-09-01

    This paper reports on oil hydrotreating that was investigated in a pilot trickle-bed reactor (TBR) at 270-350{degrees} C, 5-7 MPa, and 1.1-4.6 liquid hourly space velocity (LHSV) and with different hydrogen/oil ratios using a commercial Co-Mo/Al{sub 2}O{sub 3} catalyst. Hydrodesulfurization (HDS), hydrodeoxygenation (HDO), and metals removal were investigated by using a modified power- law kinetic model with a power term for LHSV. It was found that the HDS and HDO reactions can be described by pseudo- first-order kinetics. The removal of metals was found to be primarily due to the physical process of deposition on the catalyst bed. With the use of the kinetic data from a pilot plant, the simulation of an industrial TBR was performed. Simulated HDS and HDO, removal of metals, and prediction of catalyst deactivation agreed well with the industrial data for three charges of catalyst.

  20. Prospective, multicenter randomized GITMO/IIL trial comparing intensive (R-HDS) versus conventional (CHOP-R) chemoimmunotherapy in high-risk follicular lymphoma at diagnosis: the superior disease control of R-HDS does not translate into an overall survival advantage.

    Science.gov (United States)

    Ladetto, Marco; De Marco, Federica; Benedetti, Fabio; Vitolo, Umberto; Patti, Caterina; Rambaldi, Alessandro; Pulsoni, Alessandro; Musso, Maurizio; Liberati, Anna M; Olivieri, Attilio; Gallamini, Andrea; Pogliani, Enrico; Rota Scalabrini, Delia; Callea, Vincenzo; Di Raimondo, Francesco; Pavone, Vincenzo; Tucci, Alessandra; Cortelazzo, Sergio; Levis, Alessandro; Boccadoro, Mario; Majolino, Ignazio; Pileri, Alessandro; Gianni, Alessandro M; Passera, Roberto; Corradini, Paolo; Tarella, Corrado

    2008-04-15

    In this randomized multicenter study of 136 patients, 6 courses of CHOP (cyclo-phosphamide/doxorubicin/vincristine/prednisone) followed by rituximab (CHOP-R) were compared with rituximab-supplemented high-dose sequential chemotherapy with autografting (R-HDS) to assess the value of intensified chemo-therapy as a first-line treatment for high-risk follicular lymphoma (FL) after the introduction of monoclonal antibodies. The analysis was intention to treat with event-free survival (EFS) as the primary endpoint. Complete remission (CR) was 62% with CHOP-R and 85% with R-HDS (P HDS patients (P HDS in 71% of cases. Salvage R-HDS had an 85% CR rate and a 68% 3-year EFS (MFU, 30 months). We conclude that (1) achieving MR is critical for effective disease control, regardless of which treatment is used; (2) R-HDS ensures superior disease control and molecular outcome than CHOP-R, but no OS improvement; and (3) CHOP-R failures have a good outcome after salvage R-HDS, suggesting that relapsed/refractory FL could be the most appropriate setting for R-HDS-like treatments. This trial was registered at www.clinicaltrials.gov as no. NCT00435955.

  1. Sulfide catalysts made of cobalt and hydroxyapatite; Catalyseurs sulfures a base de cobalt et d`hydroxyapatite

    Energy Technology Data Exchange (ETDEWEB)

    El Ouassouli, A.; Ezzemouri, S.; Ezzamarty, A.; Lakhdar, M. [Faculte des Sciences Hassan 2, Casablanca (Morocco). Lab. de Catalyse Heterogene; Leglise, J. [Centre National de la Recherche Scientifique (CNRS-ISMRA) Lab. de Catalyse et Spectrochimie, 14 - Caen (France)

    1999-07-01

    We have prepared a series of catalysts combining cobalt and a hydroxyapatite by coprecipitation in a basic medium. These sulfided solids catalyze the hydro-desulfurization of dimethyl-disulfide at 360 deg C and its hydrogenolysis int CH{sub 3}SH at 200 deg C. The coprecipitated solids are found more active than the impregnated catalysts because they exhibit a better dispersion of the active Co-S phase at higher Co content. With the precipitated catalysts, Co ions substitute for Ca ions into the apatite structure. The formation of large sulfide particles is thus more difficult as a result of sulfiding because the Co ions have to move to the surface. The apatite catalysts are intrinsically as active as their homologous Co/Al{sub 2}O{sub 3} (used in gas oils desulfurization. (authors) 20 refs.

  2. A Big Five facet analysis of a psychopath: The validity of the HDS mischievous scale of sub-clinical psychopathy.

    Science.gov (United States)

    Furnham, Adrian; Crump, John

    2016-04-01

    Around 5,700 British adults completed the NEO-PI-R, which measures the Big Five Personality factors at the Domain and the Facet level, as well as the Hogan Development Survey (HDS); measure of Anti-Social Personality Disorder called Mischievous. Previous work in this field has used clinical measures of psychopathy and either student or patient samples. This sought to validate this measure by comparing NEO facet correlational results with other studies. The Mischievous score from the HDS was the criterion variable in the correlations and multiple regressions. Mischievous people were Disagreeable, Stable, Extraverts, lacking in Conscientiousness. Facet analysis showed them high on Excitement-seeking but low of Straightforwardness, Anxiety and Deliberation. Limitations are of the study are discussed.

  3. Combining high-dispersion spectroscopy (HDS) with high contrast imaging (HCI): Probing rocky planets around our nearest neighbors

    CERN Document Server

    Snellen, Ignas; Birkby, Jayne; Brandl, Bernhard; Brogi, Matteo; Keller, Christoph; Kenworthy, Matthew; Schwarz, Henriette; Stuik, Remko

    2015-01-01

    Aims: In this work, we discuss a way to combine High Dispersion Spectroscopy and High Contrast Imaging (HDS+HCI). For a planet located at a resolvable angular distance from its host star, the starlight can be reduced up to several orders of magnitude using adaptive optics and/or coronography. In addition, the remaining starlight can be filtered out using high-dispersion spectroscopy, utilizing the significantly different (or Doppler shifted) high-dispersion spectra of the planet and star. In this way, HDS+HCI can in principle reach contrast limits of ~1e-5 x 1e-5, although in practice this will be limited by photon noise and/or sky-background. Methods: We present simulations of HDS+HCI observations with the E-ELT, both probing thermal emission from a planet at infrared wavelengths, and starlight reflected off a planet atmosphere at optical wavelengths. For the infrared simulations we use the baseline parameters of the E-ELT and METIS instrument, with the latter combining extreme adaptive optics with an R=100,...

  4. Subaru/HDS Abundances in Three Giant Stars in the Ursa Minor Dwarf Spheroidal Galaxy

    CERN Document Server

    Sadakane, K; Ikuta, C; Aoki, W; Jablonka, P; Tajitsu, A

    2004-01-01

    With the HDS (High Dispersion Spectrograph) on the Subaru telescope, we obtained high resolution optical region spectra of three red giant stars (cos 4, cos 82, and cos 347) in the Ursa Minor dwarf spheriodal galaxy. Chemical abundances in these stars have been analysed for 26 elements including alpha-, iron-peak, and neutron capture elements. All three stars show low abundances of alpha-elements (Mg, Si, and Ca) and two stars (cos 82 and cos 347) show high abundance of Mn compared to Galactic halo stars of similar metallicity. One star (cos 4) has been confirmed to be very metal deficient ([Fe/H]=-2.7) and found to show anomalously low abundances of Mn, Cu, and Ba. In another star cos 82 ([Fe/H]=-1.5), we have found large excess of heavy neutron-capture elements with the general abundance pattern similar to the scaled solar system r-process abundance curve. These observational results are rather puzzling: low abundances of alpha-elements and high abundance of Mn seem to sugggest a significant contribution of...

  5. High Resolution HDS/SUBARU chemical abundances of the young stellar cluster Palomar 1

    CERN Document Server

    Monaco, L; Correnti, M; Bonifacio, P; Geisler, D

    2010-01-01

    Context. Palomar\\,1 is a peculiar globular cluster (GC). It is the youngest Galactic GC and it has been tentatively associated to several of the substructures recently discovered in the Milky Way (MW), including the Canis Major (CMa) overdensity and the Galactic Anticenter Stellar Structure (GASS). Aims. In order to provide further insights into its origin, we present the first high resolution chemical abundance analysis for one red giant in Pal\\,1. Methods. We obtained high resolution (R=30000) spectra for one red giant star in Pal\\,1 using the High Dispersion Spectrograph (HDS) mounted at the SUBARU telescope. We used ATLAS-9 model atmospheres coupled with the SYNTHE and WIDTH calculation codes to derive chemical abundances from the measured line equivalent widths of 18 among $\\alpha$, Iron-peak, light and heavy elements. Results. The Palomar~1 chemical pattern is broadly compatible to that of the MW open clusters population and similar to disk stars. It is, instead, remarkably different from that of the Sa...

  6. DD-HDS: A method for visualization and exploration of high-dimensional data.

    Science.gov (United States)

    Lespinats, Sylvain; Verleysen, Michel; Giron, Alain; Fertil, Bernard

    2007-09-01

    Mapping high-dimensional data in a low-dimensional space, for example, for visualization, is a problem of increasingly major concern in data analysis. This paper presents data-driven high-dimensional scaling (DD-HDS), a nonlinear mapping method that follows the line of multidimensional scaling (MDS) approach, based on the preservation of distances between pairs of data. It improves the performance of existing competitors with respect to the representation of high-dimensional data, in two ways. It introduces (1) a specific weighting of distances between data taking into account the concentration of measure phenomenon and (2) a symmetric handling of short distances in the original and output spaces, avoiding false neighbor representations while still allowing some necessary tears in the original distribution. More precisely, the weighting is set according to the effective distribution of distances in the data set, with the exception of a single user-defined parameter setting the tradeoff between local neighborhood preservation and global mapping. The optimization of the stress criterion designed for the mapping is realized by "force-directed placement" (FDP). The mappings of low- and high-dimensional data sets are presented as illustrations of the features and advantages of the proposed algorithm. The weighting function specific to high-dimensional data and the symmetric handling of short distances can be easily incorporated in most distance preservation-based nonlinear dimensionality reduction methods.

  7. SUBARU HDS Observations of a Balmer-Dominated Shock in Tycho's Supernova Remnant

    CERN Document Server

    Lee, Jae-Joon; Raymond, John; Ghavamian, Parviz; Pyo, Tae-Soo; Jitsu, Akito Ta; Hayashi, Masahiko

    2007-01-01

    We present an Ha spectral observation of a Balmer-dominated shock on the eastern side of Tycho's supernova remnant using the Subaru Telescope. Utilizing the High Dispersion Spectrograph (HDS), we measure the spatial variation of the line profile between preshock and postshock gas. Our observation clearly shows a broadening and centroid shift of the narrow-component postshock Ha line relative to the Ha emission from the preshock gas. The observation supports the existence of a thin precursor where gas is heated and accelerated ahead of the shock. Furthermore, the spatial profile of the emission ahead of the Balmer filament shows a gradual gradient in the Ha intensity and line width ahead of the shock. We propose that this region (~10^16 cm) is likely to be the spatially resolved precursor. The line width increases from ~30 up to ~45 km/s, and its central velocity shows a redshift of ~5 km/s across the shock front. The characteristics of the precursor are consistent with a cosmic-ray precursor, although the pos...

  8. Subaru HDS Transmission Spectroscopy of the Transiting Extrasolar Planet HD 209458b

    CERN Document Server

    Narita, N; Winn, J N; Turner, E L; Aoki, W; Leigh, C J; Sato, B; Tamura, M; Yamada, T; Narita, Norio; Suto, Yasushi; Winn, Joshua N.; Turner, Edwin L.; Aoki, Wako; Leigh, Christopher J.; Sato, Bun'ei; Tamura, Motohide; Yamada, Toru

    2005-01-01

    We have searched for absorption in several common atomic species due to the atmosphere or exosphere of the transiting extrasolar planet HD 209458b, using high precision optical spectra obtained with the Subaru High Dispersion Spectrograph (HDS). Previously we reported an upper limit on H alpha absorption of 0.1% (3 sigma) within a 5.1\\AA band. Using the same procedure, we now report upper limits on absorption due to the optical transitions of Na D, Li, H alpha, H beta, H gamma, Fe, and Ca. The 3 sigma upper limit for each transition is approximately 1% within a 0.3\\AA band (the core of the line), and a few tenths of a per cent within a 2\\AA band (the full line width). The wide-band results are close to the expected limit due to photon-counting (Poisson) statistics, although in the narrow-band case we have encountered unexplained systematic errors at a few times the Poisson level. These results are consistent with all previously reported detections and upper limits, but are significantly more sensitive.

  9. PROGRESS IN CATALYST AND PROCESS DEVELOPMENT FOR LOW SULFUR AND LOW AROMATICS DIESEL PRODUCTION%低硫低芳烃柴油生产技术开发进展

    Institute of Scientific and Technical Information of China (English)

    周勇; 韩崇仁

    2003-01-01

    The article includes three parts: ①The development and performance of FH-DS catalyst for deep and ultra-deep distillate HDS; ②The single stage HDS/HDA hydrotreating process for the production of low sulfur and low aromatics diesels from straight run and coker AGO by using highly active base metal catalyst at moderate pressure; ③A two-stage aromatics saturation system utilizing noble metal catalyst in the second stage developed for production of low sulfur and low aromatics diesel from LCO. FDA catalyst developed by FRIPP has high activity for aromatics saturation together with high tolerance for sulfur and nitrogen in the feed. The process is effective in reducing density and increasing cetane number.

  10. Effect of MCM-41 on the physicochemical properties of Mo and NiMo catalysts and their performance in DBT conversion

    Energy Technology Data Exchange (ETDEWEB)

    Grzechowiak, Jolanta R.; Mrozinska, Karolina; Masalska, Aleksandra [Department of Chemistry and Technology of Fuel, Faculty of Chemistry, Wroclaw University of Technology, 7/9 Gdanska Str., 50-344 Wroclaw (Poland); Goralski, Jacek; Rynkowski, Jacek [Institute of General and Ecological Chemistry, Technical University of Lodz, 36 Zwirki Str., 90-924 Lodz (Poland); Tylus, Wlodzimierz [Institute of Inorganic Technology, Faculty of Chemistry, Wroclaw University of Technology, Smoluchowskiego Str., 50-353 Wroclaw (Poland)

    2006-05-15

    The influence of mesoporous materials on the properties and HDS activity of Mo and NiMo catalysts was investigated for supports containing 50wt.% of MCM-41. A series of catalysts was characterized by different techniques (S{sub BET}, TPD-NH{sub 3}, TPR, SEM, XPS) and tested in dibenzothiophene (DBT) conversion. On the surface of the catalysts containing mesoporous materials, agglomerations of the Mo oxo-species were observed. The presence of MCM-41 in the support visibly weakened the promoting effect of TiO{sub 2} on the reducibility of Mo oxides. The results of DBT HDS showed that the NiMo catalyst supported on MCM-41 was not only less efficient than that supported on Al{sub 2}O{sub 3} but also that supported on Al{sub 2}O{sub 3}-TiO{sub 2}. From the distribution of DBT HDS products we can conclude that over catalysts containing MCM-41 the desulphurization of DBT runs mostly via the DDS route. (author)

  11. Novel bimetallic dispersed catalysts for temperature-programmed coal liquefaction. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Chunshan Song; Schobert, H.H.; Parfitt, D.P. [and others

    1997-11-01

    Development of new catalysts is a promising approach to more efficient coal liquefaction. It has been recognized that dispersed catalysts are superior to supported catalysts for primary liquefaction of coals, because the control of initial coal dissolution or depolymerization requires intimate contact between the catalyst and coal. This research is a fundamental and exploratory study on catalytic coal liquefaction, with the emphasis on exploring novel bimetallic dispersed catalysts for coal liquefaction and the effectiveness of temperature-programmed liquefaction using dispersed catalysts. The primary objective of this research was to explore novel bimetallic dispersed catalysts from organometallic molecular precursors, that could be used in low concentrations but exhibit relatively high activity for efficient hydroliquefaction of coals under temperature-programmed conditions. We have synthesized and tested various catalyst precursors in liquefaction of subbituminous and bituminous coals and in model compound studies to examine how do the composition and structure of the catalytic precursors affect their effectiveness for coal liquefaction under different reaction conditions, and how do these factors affect their catalytic functions for hydrogenation of polyaromatic hydrocarbons, for cleavage of C-C bonds in polycyclic systems such as 4-(1-naphthylmethyl)bibenzyl, for hydrogenolysis of C-O bond such as that in dinaphthylether, for hydrodeoxygenation of phenolic compounds and other oxygen-containing compounds such as xanthene, and for hydrodesulfurization of polycyclic sulfur compounds such as dibenzothiophene. The novel bimetallic and monometallic precursors synthesized and tested in this project include various Mo- and Fe-based compounds.

  12. Integration of non linearities in the economic refining model. Case of the hydro-desulfurization unit; Prise en compte de non-linearites dans la modelisation economique du raffinage. Cas de l`unite d`hydrodesulfuration

    Energy Technology Data Exchange (ETDEWEB)

    Baudouin, C.

    1998-12-08

    In recent years, the modifications in oil products demand and the increased quality requirements of European specifications have driven the oil industry towards more and more complex refining schemes. This situation should become even more pronounced in the future. Under these conditions, a technical analysis of the units operation must be carried out and combined with an economic approach. The research undertaken is divided into two parts. The first part is dedicated to the study of the European refining industry and its representation by the classic linear programming model. In these models, the units` operation is represented by typical running. The technical parameters are not explicitly taken into account. Therefore, in order to meet future requirements and to represent this activity in the best way, the current model must be improved. The second part relates to an analysis with forecasts future developments in the European refining sector up to 2010 and how linear programming models themselves will be adapted. Thus, the straight run gas oil hydro-desulfurization unit is completely redefined. The operating conditions and the design parameters of this unit are introduced into the model. Depending on the feed, they determine the performances and the material balance of the unit. Some of these operating conditions are new variables and appear in non linear equations. Therefore, we need non linear programming (the augmented Lagrangians method) to solve this detailed model. The results of the second part confirm those determined by the first part. They also provide us with a better representation of the hydro-desulfurization unit (taking the optimisation of the operating conditions into account). Using these models and the analysis described above, we can develop an outline plan of the future European refining industry. This shows that sizeable investments in both conventional and deep conversion capacity will be required to meet the requirements of changes in

  13. Dispersed catalysts for co-processing and coal liquefaction

    Energy Technology Data Exchange (ETDEWEB)

    Bockrath, B.; Parfitt, D.; Miller, R. [Pittsburgh Energy Technology Center, PA (United States)

    1995-12-31

    The basic goal is to improve dispersed catalysts employed in the production of clean fuels from low value hydrocarbons. The immediate objective is to determine how the properties of the catalysts may be altered to match the demands placed on them by the properties of the feedstock, the qualities of the desired end products, and the economic constraints put upon the process. Several interrelated areas of the application of dispersed catalysts to co-processing and coal conversion are under investigation. The first involves control of the selectivity of MoS{sub 2} catalysts for HDN, HDS, and hydrogenation of aromatics. A second area of research is the development and use of methods to evaluate dispersed catalysts by means of activity and selectivity tests. A micro-flow reactor has been developed for determining intrinsic reactivities using model compounds, and will be used to compare catalysts prepared in different ways. Micro-autoclaves will also be used to develop data in batch experiments at higher partial pressures of hydrogen. The third area under investigation concerns hydrogen spillover reactions between MoS{sub 2} catalysts and carbonaceous supports. Preliminary results obtained by monitoring H{sub 2}/D{sub 2} exchange reactions with a pulse-flow microreactor indicate the presence of spillover between MoS{sub 2} and a graphitic carbon. A more complete study will be made at a later stage of the project. Accomplishments and conclusions are discussed.

  14. Facile synthesis of iron phosphide Fe{sub 2}P nanoparticle and its catalytic performance in thiophene hydrodesulfurization

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Xiang, E-mail: huangxianghd@gmail.com; Dong, Qing; Huang, He; Yue, Li; Zhu, Zhibin; Dai, Jinhui [Ocean University of China, Institute of Materials Science and Engineering (China)

    2014-12-15

    Nanosized iron phosphide (Fe{sub 2}P) was successfully synthesized under mild solvothermal conditions with environmental-friendly raw materials. The key synthetic parameters including the molar ratios of Fe/P in initial mixture, the solvothermal treatment temperature, and duration were systematically investigated, and the samples were characterized using X-ray diffraction, energy dispersive spectroscopy, and transmission electron microscopy. These measurements indicated that the nanoparticles are pure Fe{sub 2}P with an average particle size of about 20 nm. Furthermore, the catalytic performance of the as-synthesized Fe{sub 2}P/ZSM-5 in thiophene hydrodesulfurization was tested. The results showed that the desulfurization efficiency of thiophene can reach up to 88 % after 3 h with a stable catalytic activity during the whole examination process.

  15. High Dispersion Spectroscopy of Solar-Type Superflare Stars With Subaru/HDS

    Science.gov (United States)

    Notsu, Yuta; Honda, Satoshi; Maehara, Hiroyuki; Notsu, Shota; Shibayama, Takuya; Namekata, Kosuke; Nogami, Daisaku; Shibata, Kazunari

    2016-07-01

    Superflares are flares that release total energy 10-104times greater than that of the biggest solar flares ( 1032 erg). Recent Kepler-space-telescope observations found more than 1000superflares on a few hundred solar-type stars (Maehara et al. 2012, Nature; Shibayama et al. 2013, ApJS, Maehara et al. 2015 EPS).Suchsuperflare stars show quasi-periodicbrightnessvariations with the typical period of from one to a few tens of days. Such variations are thought to be caused by the rotation of the star with large starspots (Notsu et al. 2013, ApJ). However, spectroscopic observations are needed in order to confirm whether the variation is really due to the rotation and whether superflares can occur on ordinary single stars similar to our Sun.Then we have carried out spectroscopic observations for 50 solar-type superflare stars with Subaru/HDS (Notsu et al. 2015a&b, PASJ). As a result, more than half (34 stars) of the targetstars show no evidence of binarity, and the atmospheric parameters of these stars are in the range of solar-type stars.The detailed analyses for these 34 stars show that (1) the projected rotational velocities (v sin i) are consistent with the rotational velocities estimated from the brightness variations, (2)there is a correlation between the brightness variation amplitude and the intensity of Ca II IR triplet line. These results support that the brightness variation discussed above is explained bythe rotation of a star with large starspots. (The contents of this poster were already summarized in the proceeding of IAU Symposium S320 (Notsu et al. 2016 IAUS in press, arXiv:1510.08143))

  16. Hyperfine Structure in Rotational Spectra of Deuterated Molecules: the Hds and ND_3 Case Studies

    Science.gov (United States)

    Cazzoli, Gabriele; Puzzarini, Cristina

    2016-06-01

    The determination of hyperfine parameters (quadrupole-coupling, spin-spin coupling, and spin-rotation constants) is one of the aims of high-resolution rotational spectroscopy. These parameters are relevant not only from a spectroscopic point of view, but also from a physical and/or chemical viewpoint, as they might provide detailed information on the chemical bond, structure, etc. In addition, the hyperfine structure of rotational spectra is so characteristic that its analysis may help in assigning the spectra of unknown species. In astronomical observations, hyperfine structures of rotational spectra would allow us to gain information on column densities and kinematics, and the omission of taking them into account can lead to a misinterpretation of the line width of the molecular emission lines. Nevertheless, the experimental determination of hyperfine constants can be a challenge not only for actual problems in resolving hyperfine structures themselves, but also due to the lack of reliable estimates or the complexity of the hyperfine structure itself. It is thus important to be able to rely on good predictions for such parameters, which can nowadays be provided by quantum-chemical calculations. In fact, the fruitful interplay of experiment and theory will be demonstrated by means of two study cases: the hypefine structure of the rotational spectra of HDS and ND_3. From an experimental point of view, the Lamb-dip technique has been employed to improve the resolving power in themillimeter- and submillimeterwave frequency range by at least one order of magnitude, thus making it possible to perform sub-Doppler measurements as well as to resolve narrow hyperfine structures. Concerning theory, it will be demonstrated that high-level calculations can provide quantitative estimates for hyperfine parameters (quadrupole coupling constants, spin-rotation tensors, spin-spin couplings, etc.) and shown how theoretical predictions are often essential for a detailed analysis of

  17. Effect of temperature in hydrocracking of light cycle oil on a noble metal-supported catalyst for fuel production

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez, A.; Arandes, J.M.; Castano, P.; Olazar, M.; Bilbao, J. [Universidad del Pais Vasco (UPV-EHU), Departamento de Ingenieria Quimica, Bilbao (Spain); Barona, A. [Universidad del Pais Vasco (UPV-EHU), Escuela de Ingenieria, Departamento de Ingenieria Quimica y Medio Ambiente, Alda, Urkijo s/n, Bilbao (Spain)

    2012-04-15

    The effect of temperature has been studied in hydrocracking of light cycle oil (LCO), byproduct of fluidized catalytic cracking (FCC) units on a bifunctional catalyst (Pt-Pd/HY zeolite). The increase in both temperature and H{sub 2} partial pressure have an important attenuating effect on catalyst deactivation, given that they decrease sulfur equilibrium adsorption and enhance hydrocracking of coke precursors. Therefore, the catalyst maintains significant hydrodesulfurization and hydrocracking activity. As the temperature is increased, hydrocracking conversion and naphtha selectivity increase, although there is no significant dearomatization of the medium distillate fraction in the range of the studied experimental conditions. 400 C is the more suitable temperature for obtaining a high yield of naphtha with a high content of i-paraffins. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  18. Cloning and function analyses of HDS gene from Artemisia annua%黄花蒿HDS基因的克隆与功能分析

    Institute of Scientific and Technical Information of China (English)

    张祖荣; 廖志华; 彭梅芳

    2012-01-01

    目的 克隆获得黄花蒿MEP途径中必需关键酶——羟甲基丁烯基-4-磷酸合成酶基因(HDS),并进行生物信息学分析和功能互补分析研究.方法 对已知的其他种子植物HDS基因的核苷酸序列进行多重序列比对,选取保守区域设计简并引物,利用同源扩增和cDNA末端快速扩增技术从黄花蒿中获得目的基因;利用BLAST进行序列比对,ORF Finder寻找开放阅读框,并用MEGA3.0中的临位相联法构建进化树.结果 得到1条长2324 bp的HDS cDNA序列,其ORF 框长1854 bp,编码617个氨基酸残基的蛋白;生物信息学分析显示,黄花蒿HDS基因AaHDS与其他种子植物来源的HDS高度同源;功能互补分析表明,AaHDS能互补突变菌株Escherichia coli MG1655 ara<> HDS中缺失的HDS功能,使突变菌株恢复生长,证明AaHDS具有典型的HDS基因功能.结论 首次克隆获得黄花蒿HDS基因,为青蒿素的代谢工程研究提供相应的基础.%Objective To obtain the indispensable key enzyme-hydroxide methyl enylamino 4-cyclodiphosphate synthase (HDS) gene involved in the MEP pathway cloned from Artemisia annua and conduct bioinformatic and functional complementation analysis. Methods To perform multiple sequence alignment for the nucleotide acid sequence of the other reported seed plants' HDS gene, to select conservative areas for designing degenerate primers, and to gain the aim gene from A. Annua through homologous expanding and cDNA bottom speedily expanding technique. To perform sequence alignment using BLAST, to identify open reading frame (ORF) using ORF Finder, and to construct phylogenetic tree using neighbor joining (NJ) ways in MEGA3.0. Results The obtained HDS cDNA sequence was 2 324 bp containing a 1 854 bp ORF and encoding a 617-amino acid protein. Bioinformatic analysis showed that AaHDS was homologous with HDS derived from other seed plant species. Functional complementation analysis indicated that AaHDS could make up the short HDS

  19. Homogeneous catalysts

    CERN Document Server

    Chadwick, John C; Freixa, Zoraida; van Leeuwen, Piet W N M

    2011-01-01

    This first book to illuminate this important aspect of chemical synthesis improves the lifetime of catalysts, thus reducing material and saving energy, costs and waste.The international panel of expert authors describes the studies that have been conducted concerning the way homogeneous catalysts decompose, and the differences between homogeneous and heterogeneous catalysts. The result is a ready reference for organic, catalytic, polymer and complex chemists, as well as those working in industry and with/on organometallics.

  20. Novel bimetallic dispersed catalysts for temperature-programmed coal liquefaction. Technical progress report, July--September 1996

    Energy Technology Data Exchange (ETDEWEB)

    Yoneyama, Yoshiharu; Wei, B.; Reddy, K.M.; Song, C.; Schobert, H.H.

    1997-01-01

    This quarterly report describes recent work on two related subjects: (1) effect of dispersed molybdenum catalyst precursor and the influence of water addition on C-O bond cleavage, aromatic hydrogenation and hydrodeoxygenation under coal liquefaction conditions, and (2) the effect of dispersed molybdenum catalyst precursor on the molecular weight reduction and desulfurization of petroleum resids related to coal/petroleum resids coprocessing. Technical progress on the C-O bond cleavage of 2,2{prime}-dinaphthyl ether and high temperature simulated distillation GC and HDS study on catalytic upgrading of atmospheric and vacuum resids.

  1. Study on Sulifdation Degree and Morphology of MoS2 Catalyst Derived from Various Molybdate Precursors

    Institute of Scientific and Technical Information of China (English)

    Zhang Le; Li Mingfeng; Nie Hong

    2014-01-01

    The MoS2 catalysts were prepared from various molybdate precursors including inorganic and organic molybdate compounds. The sulifdation degree and morphology of active phases of MoS2 activated by various molybdate precursors in H2S/H2 stream at different temperatures were studied by X-ray photoelectron spectroscopy (XPS) and high-resolution trans-mission electron microscopy (HRTEM). The organic molybdate precursors lead to MoS2 catalysts with higher sulifdation degree and smaller active phases to demonstrate higher catalytic activity during hydrodesulfurizaiton (HDS) of 4,6-DMDBT.

  2. Circulating progenitors following high-dose sequential (HDS) chemotherapy with G-CSF: short intervals between drug courses severely impair progenitor mobilization.

    Science.gov (United States)

    Tarella, C; Caracciolo, D; Gavarotti, P; Bondesan, P; Cherasco, C; Omedè, P; Bregni, M; Siena, S; Gianni, A M; Pileri, A

    1995-08-01

    Sequential administration of high-dose chemotherapy courses possibly allows extensive in vivo purging before circulating progenitor collection for autograft. To evaluate whether progenitor cell mobilization was negatively affected by repeated high-dose chemotherapy courses, we studied 23 lymphoma patients undergoing the HDS regimen. The scheme includes the sequential administration of cyclophosphamide (CY) given at 7 g/m2 and etoposide (VP16) given at 2 g/m2, each followed by G-CSF (filgrastim) at 5 micrograms/kg/day. Eleven patients received the standard HDS sequence, with a short interval between first and second myelotoxic courses of less than 45 days (median: 30 days); the remaining 12 patients received a modified HDS where the interval between first and second high-dose course was protracted over 2 months (median: 70 days); in this latter group, 2 to 4 conventional debulking courses were delivered prior to HDS. In patients receiving the standard HDS, progenitor mobilization following the first course was consistently high (median circulating CFU-GM/ml peak value: 29,022); however, significantly lower values were observed at the second course (median CFU-GM/ml peak value 3757, P = 0.002). Circulating BFU-E and CD34+ cell values paralleled those of CFU-GM. No significant difference was observed in progenitor mobilization following either course in patients receiving HDS with extended interval (median circulating CFU-GM/ml peak value: 14,363 vs 9208, at first and second course respectively, P = 0.27). Eleven patients had their progenitor cells harvested following the second delayed course and 2-4 leucaphereses allowed very satisfactory harvests in all of them (CFU-GM/kg ranging from 39-340 x 10(4)).(ABSTRACT TRUNCATED AT 250 WORDS)

  3. New catalysts for coal processing: Metal carbides and nitrides

    Energy Technology Data Exchange (ETDEWEB)

    S. Ted Oyama; David F. Cox

    1999-12-03

    The subject of this research project was to investigate the catalytic properties of a new class of materials, transition metal carbides and nitrides, for treatment of coal liquid and petroleum feedstocks. The main objectives were: (1) preparation of catalysts in unsupported and supported form; (2) characterization of the materials; (3) evaluation of their catalytic properties in HDS and HDN; (4) measurement of the surface properties; and (5) observation of adsorbed species. All of the objectives were substantially carried out and the results will be described in detail below. The catalysts were transition metal carbides and nitrides spanning Groups 4--6 in the Periodic Table. They were chosen for study because initial work had shown they were promising materials for hydrotreating. The basic strategy was first to prepare the materials in unsupported form to identify the most promising catalyst, and then to synthesize a supported form of the material. Already work had been carried out on the synthesis of the Group VI compounds Mo{sub 2}C, Mo{sub 2}N, and WC, and new methods were developed for the Group V compounds VC and NbC. All the catalysts were then evaluated in a hydrotreating test at realistic conditions. It was found that the most active catalyst was Mo{sub 2}C, and further investigations of the material were carried out in supported form. A new technique was employed for the study of the bulk and surface properties of the catalysts, near edge x-ray absorption spectroscopy (NEXAFS), that fingerprinted the electronic structure of the materials. Finally, two new research direction were explored. Bimetallic alloys formed between two transition metals were prepared, resulting in catalysts having even higher activity than Mo{sub 2}C. The performance of the catalysts in hydrodechloration was also investigated.

  4. Catalyst mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Masel, Richard I.; Rosen, Brian A.

    2017-02-14

    Catalysts that include at least one catalytically active element and one helper catalyst can be used to increase the rate or lower the overpotential of chemical reactions. The helper catalyst can simultaneously act as a director molecule, suppressing undesired reactions and thus increasing selectivity toward the desired reaction. These catalysts can be useful for a variety of chemical reactions including, in particular, the electrochemical conversion of CO.sub.2 or formic acid. The catalysts can also suppress H.sub.2 evolution, permitting electrochemical cell operation at potentials below RHE. Chemical processes and devices using the catalysts are also disclosed, including processes to produce CO, OH.sup.-, HCO.sup.-, H.sub.2CO, (HCO.sub.2).sup.-, H.sub.2CO.sub.2, CH.sub.3OH, CH.sub.4, C.sub.2H.sub.4, CH.sub.3CH.sub.2OH, CH.sub.3COO.sup.-, CH.sub.3COOH, C.sub.2H.sub.6, O.sub.2, H.sub.2, (COOH).sub.2, or (COO.sup.-).sub.2, and a specific device, namely, a CO.sub.2 sensor.

  5. The Study of Peptide Vaccine HDS from Streptococcus mutans Glucosyltransferase%葡糖基转移酶多肽疫苗HDS免疫大鼠的实验研究

    Institute of Scientific and Technical Information of China (English)

    丁芸; 凌均棨; 陈罕

    2003-01-01

    目的动物体内研究葡糖基转移酶多肽疫苗HDS免疫原性和防龋效果.方法构建大鼠人工龋模型,分别用人工抗原HDS-KLH,多肽抗原HDS,葡糖基转移酶(GTF)免疫大鼠, 酶联免疫吸附法检测大鼠血清和唾液中抗HDS、GTF抗体;体视显微镜下观察各组大鼠磨牙龋坏情况,并用Keyes计分法计分.结果 HDS-KLH免疫组大鼠唾液、血清中抗HDS IgG和IgA水平均高于对照组(P<0.05);HDS-KLH,HDS,GTF免疫组大鼠龋Keyes计分均低于对照组(P<0.01),光滑面防龋效果最为显著.结论人工抗原HDS-KLH能刺激机体产生针对GTF的保护性免疫,并减少实验大鼠龋齿发生.

  6. Photo-oxidation catalysts

    Science.gov (United States)

    Pitts, J. Roland; Liu, Ping; Smith, R. Davis

    2009-07-14

    Photo-oxidation catalysts and methods for cleaning a metal-based catalyst are disclosed. An exemplary catalyst system implementing a photo-oxidation catalyst may comprise a metal-based catalyst, and a photo-oxidation catalyst for cleaning the metal-based catalyst in the presence of light. The exposure to light enables the photo-oxidation catalyst to substantially oxidize absorbed contaminants and reduce accumulation of the contaminants on the metal-based catalyst. Applications are also disclosed.

  7. Highly dispersed metal catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Xin; West, William L.; Rhodes, William D.

    2016-11-08

    A supported catalyst having an atomic level single atom structure is provided such that substantially all the catalyst is available for catalytic function. A process of forming a single atom catalyst unto a porous catalyst support is also provided.

  8. Catalyst Architecture

    DEFF Research Database (Denmark)

    Kiib, Hans; Marling, Gitte; Hansen, Peter Mandal

    2014-01-01

    How can architecture promote the enriching experiences of the tolerant, the democratic, and the learning city - a city worth living in, worth supporting and worth investing in? Catalyst Architecture comprises architectural projects, which, by virtue of their location, context and their combination...... of programs, have a role in mediating positive social and/or cultural development. In this sense, we talk about architecture as a catalyst for: sustainable adaptation of the city’s infrastructure appropriate renovation of dilapidated urban districts strengthening of social cohesiveness in the city development...

  9. Heterogeneous Catalysts

    NARCIS (Netherlands)

    Dakka, J.; Sheldon, R.A.; Sanderson, W.A.

    1997-01-01

    Abstract of GB 2309655 (A) Heterogeneous catalysts comprising one or more metal compounds selected from the group consisting of tin, molybdenum, tungsten, zirconium and selenium compounds deposited on the surface of a silicalite are provided. Preferably Sn(IV) and/or Mo(VI) are employed. The cat

  10. A bright side, facet analysis of histrionic personality disorder: the relationship between the HDS Colourful factor and the NEO-PI-R facets in a large adult sample.

    Science.gov (United States)

    Furnham, Adrian

    2014-01-01

    This study looks at "bright-side," Big Five Personality trait correlates of a "dark-side" Personality Disorder, namely Histrionic Personality Disorder (HPD). More than 5000 British adults completed the Neuroticism Extraversion Openness Personality Inventory-Revised (Costa & McCrae, 1985), which measures the Big Five Personality factors at the Domain (Super Factor) and the Facet (Factor) level, as well as the Hogan Development Survey (HDS; Hogan & Hogan, 2009), which has a measure of HPD, exclusively called "Colourful" in the HDS terminology. Correlation and regression results confirmed many of the associations between these "bright" and "dark" side individual difference variables. The Colourful (HPD) score from the HDS was the criterion variable in all analyses. Colourful individuals are high on Extraversion and Openness, but also Stable and disagreeable. The Facet analysis identified Assertiveness and Immodesty as particularly characteristic of that type. The study confirmed work on HPD using different population groups and different measures, showing that personality traits are predictable and correlated with various personality disorders.

  11. Study on the influence of nickel and Al{sub 2}O{sub 3} support on MoS{sub 2} as hydrodenitrogenation catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Hein, J.; Hrabar, A.; Gutierrez, O.Y.; Lercher, J.A. [Technische Univ. Muenchen, Garching (Germany). Catalysis Research Center

    2012-07-01

    Alumina-supported Mo and Ni-Mo catalysts as well as an unsupported NiMo catalyst were characterized and tested in the hydrodenitrogenation (HDN) of quinoline in the presence of dibenzothiophene (DBT). The supported catalysts had a well dispersed MoS{sub 2} phase with an average stacking degree around two and slabs length below 10 nm. The unsupported NiMo sulfide catalyst exhibited long, multistacked MoS{sub 2} slabs and contained segregated Ni{sub x}S{sub y} phases. The formation of the Ni-Mo-S phase in both Ni containing catalysts was verified by X-ray absorption spectroscopy, whereas the concentration of coordinatively unsaturated sites was higher for the supported Mo and Ni-Mo catalysts than for the unsupported one. All catalysts were active in the HDN of quinoline and hydrodesulfurization of DBT. The catalytic activity increased in the order Mo/Al{sub 2}O{sub 3} < NiMo/unsupported < Ni-Mo/Al{sub 2}O{sub 3}. Thus, the influence on the catalytic activity of the promoter metal Ni is more important than the presence of a support due to the formation of the Ni-Mo-S phase (more active than MoS{sub 2}). (orig.)

  12. NiMo/Al{sub 2}O{sub 3}-MgO (x) catalysts. The effect of the prolonged exposure to ambient air on the textural and catalytic properties

    Energy Technology Data Exchange (ETDEWEB)

    Solis, D.; Klimova, T.; Ramirez, J. [Departamento de Ingenieria Quimica, Facultad de Quimica, UNAM. Cd. Universitaria,, Coyoacan (Mexico); Cortez, T. [Instituto Mexicano del Petroleo, Tratamiento de Crudo Maya, Eje central Lazaro Cardenas 152, Col. San Bartolo Atepehuacan, C.P. (Mexico)

    2004-11-24

    In the search to obtain stable catalysts for selective elimination of sulfur from gasoline, maintaining octane number, NiMo catalysts supported on Al-Mg mixed oxides were prepared by the sol-gel method and evaluated after 6-month storage in contact with ambient air, the results were compared with the freshly prepared samples. Both, freshly prepared and aged samples were characterized by nitrogen physisorption measurements (S{sub BET}), infrared spectroscopy (FT-IR) and X-ray powder diffraction (XRD) and high-resolution electron microscopy (HREM), they were tested in the thiophene hydrodesulfurization reaction.The results indicate that the incorporation of small amounts of magnesia (5mol%) into the alumina support, leads to the catalyst with low hydrogenation function and appropriate stability during prolonged contact with ambient conditions.

  13. TiO2 nanotubes supported NiW hydrodesulphurization catalysts: Characterization and activity

    Science.gov (United States)

    Palcheva, R.; Dimitrov, L.; Tyuliev, G.; Spojakina, A.; Jiratova, K.

    2013-01-01

    High surface area TiO2 nanotubes (Ti-NT) synthesized by alkali hydrothermal method were used as a support for NiW hydrodesulphurization catalyst. Nickel salt of 12-tungstophosphoric acid - Ni3/2PW12O40 was applied as oxide precursor of the active components. The catalyst was characterized by SBET, XRD, UV-vis DRS, Raman spectroscopy, XPS, TPR and HRTEM. The results obtained were compared with those for the NiW catalysts prepared over high surface area titania and alumina supports. A polytungstate phase evidenced by Raman spectroscopy was observed indicating the destruction of the initial heteropolyanion. The catalytic experiments revealed two times higher thiophene conversion on NiW catalyst supported on Ti-NT than those of catalysts supported on alumina and titania. Increased HDS activity of the NiW catalyst supported on Ti-NT could be related to a higher amount of W oxysulfide entities interacting with Ni sulfide particles as consequence of the electronic effects of the Ti-NT observed with XPS analysis.

  14. Study of NiMo/ZrO2 Catalysts for Hydrodesulfurization%NiMo/ZrO2加氢脱硫催化剂的研究

    Institute of Scientific and Technical Information of China (English)

    贾美林; P Afanasiev; M Vrinat; 李文钊; 徐恒泳; 葛庆杰

    2005-01-01

    采用共浸法制备了未经焙烧直接硫化的NiMo/ZrO2(550)、NiMo/ZrO2(650)催化剂及550℃焙烧后再硫化的NiMo/ZrO2(550)-1催化剂,在连续流动微反装置上考察了NiMo/ZrO2系列催化剂对噻吩加氢脱硫反应的催化活性,并对催化剂进行了X射线光电子能谱(XPS)和Raman光谱表征.表征结果显示,以四方相ZrO2为载体的NiMo/ZrO2(650)催化剂,由于被硫化的更完全,催化活性高于以无定形相ZrO2为载体的NiMo/ZrO2(550)催化剂,说明载体的结构影响催化剂的催化活性;550℃焙烧后的NiMo/ZrO2(550)-1催化剂的催化活性低于未经焙烧直接硫化的NiMo/ZrO2(550)催化剂,这是由于高温焙烧增加了活性组分和载体之间的相互作用,降低了催化剂的硫化程度,进而降低了其催化活性,说明这种强相互作用不利于提高催化剂的催化活性.

  15. Synthesis and characterization of vanadium nanoparticles on activated carbon and their catalytic activity in thiophene hydrodesulphurization

    Energy Technology Data Exchange (ETDEWEB)

    Pinto, Susana [Centro de Catalisis, Petroleo y Petroquimica, Escuela de Quimica, Facultad de Ciencias, Universidad Central de Venezuela, AP, Caracas 40679 (Venezuela); Centro de Quimica Organometalica y Macromolecular, Facultad de Ciencias, Universidad Central de Venezuela, AP, Caracas 47778 (Venezuela); D' Ornelas, Lindora [Centro de Quimica Organometalica y Macromolecular, Facultad de Ciencias, Universidad Central de Venezuela, AP, Caracas 47778 (Venezuela); Betancourt, Paulino [Centro de Catalisis, Petroleo y Petroquimica, Escuela de Quimica, Facultad de Ciencias, Universidad Central de Venezuela, AP, Caracas 40679 (Venezuela)], E-mail: pbetanco@strix.ciens.ucv.ve

    2008-06-30

    Vanadium nanoparticles ({approx}7 nm) stabilized on activated carbon were synthesized by the reduction of VCl{sub 3}.3THF with K[BEt{sub 3}H]. This material was characterized by inductive coupled plasma-atomic emission spectroscopy (ICP-AES), high-resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS) analyses. The catalytic performance of the carbon-supported vanadium was studied using thiophene hydrodesulfurization (HDS) as model reaction at 300 deg. C and P = 1 atm. The catalytic activity of the vanadium carbide phase on the activated carbon carrier was more significant than that of the reference catalysts, alumina supported NiMoS. The method proposed for the synthesis of such a catalyst led to an excellent performance of the HDS process.

  16. Mo/MCM-41-Type mesoporous materials doubly promoted with Fe and Ni for hydrotreating reactions

    Energy Technology Data Exchange (ETDEWEB)

    Carlos F. Linares; Patricia Amezqueta; Carlos Scott [Universidad de Carabobo, Carabobo (Venezuela). Laboratorio de Catalisis y Metales de Transicion

    2008-09-15

    A Si-MCM-41-type material was synthesized and impregnated with a Mo solution in order to get a 15% MoO{sub 3} by weight. Then, it was doubly promoted with Ni and Fe in different proportions. Information on the structure of the precursors was revealed by XRD, TPR and surface area techniques. XRD results showed that the mesoporous materials were not affected for the successive impregnations carried out; while, their specific surface areas was partially blocked. These solids were tested for vanadyl octaethyl porphyrin hydrodeporphirinization (HDP), and individual and competitive reactions of dibenzothiophene (DBT) hydrodesulfurization (HDS) and 2-methyl naphthalene (2MN) hydrogenation (HYD). The DBT HDS activity was higher than 2MN HYD, and the presence of Fe in the catalysts did not produce a synergetic effect for this reactions. However, HDP activities of doubly promoted catalysts were superior to the monopromoted ones. 28 refs., 8 figs., 5 tabs.

  17. A density functional study of inhibition of the HDS hydrogenation pathway by pyridine, benzene, and H2S on MoS2-based catalysts

    DEFF Research Database (Denmark)

    Logadottir, A.; Moses, Poul Georg; Hinnemann, Berit

    2006-01-01

    compounds. In order to understand the observed inhibitor trends. DFT studies oil (lie adsorption of benzene which is a weaker poison than pyridine, and H2S, which has no or only a very minor influence on the HYD pathway. have also been made, We find that the adsorption of pyridine is quite strong....... Furthermore, H2S is observed not to interact strongly with these sites. The present results have also provided insight into the nitrogen compound inhibition of the direct desulturization DDS pathway. The difference in the poisoning by benzene and pyridine is observed to be related to the ease with which...

  18. Catalyst Architecture

    DEFF Research Database (Denmark)

    Kiib, Hans; Marling, Gitte; Hansen, Peter Mandal

    2014-01-01

    of programs, have a role in mediating positive social and/or cultural development. In this sense, we talk about architecture as a catalyst for: sustainable adaptation of the city’s infrastructure appropriate renovation of dilapidated urban districts strengthening of social cohesiveness in the city development...... meaningful for everyone. The exhibited works are designed by SANAA, Diller Scofidio + Renfro, James Corner Field Operation, JBMC Arquitetura e Urbanismo, Atelier Bow-Wow, Ateliers Jean Nouvel, COBE, Transform, BIG, Topotek1, Superflex, and by visual artist Jane Maria Petersen....

  19. 渣油加氢装置节能优化设计%Optimization design for residue hydrodesulfurization unit

    Institute of Scientific and Technical Information of China (English)

    马书涛

    2012-01-01

    介绍了某公司新建2.5 Mt/a渣油加氢处理装置工艺概况及原设计节能措施,从操作参数、工艺流程设置及能量综合利用等方面,介绍了汽、电、燃料和水等方面的节能优化方案,并提出以下改进措施:①降低空冷入口温度,回收低温热;②降低烟气温度,提高加热炉效率;③循环氢压缩机采用背压式汽轮机;④新氢压缩机采用常规逐 级返回流程,可选用HydroCom系统,提浓氢单独设置压缩机;⑤过滤器反冲洗油直接送催化裂化装置;⑥空冷器与加热炉风机采用变频技术;⑦优化流程,降低循环水用量;⑧优化换热流程,提高发生蒸汽品质与流量;⑨设置液力透平,回收能量;⑩调整机泵选型,选择高效机泵.节能优化设计使装置能耗比原设计低296.78 MJ/t,年经济效益约为1 000 ×104 RMB¥.%The process and the original energy-saving design of a 2.5 MM TPY residue hydrodesulfuration unit are introduced. Based on the operating parameters, the design of process flow and comprehensive energy saving optimization plans for steam saving, power saving, fuel gas saving and water saving are described respectively , and corresponding improvement measures are presented: ?air cooler inlet temperature is reduced and lower-temperature heat is recovered; ②flue gas temperature is lowered and the efficiency of furnace is improved ; ③the recycle gas compressor with backpressure turbine is adopted; ④ makeup gas compressor can use conventional sequential return flow and select HydroCom system, and bleed gas compressor is provided separately; ⑤ the sump oil of feed filter is directly sent to RFCC; ⑥the variable frequency technology is applied for the air cooler and the heater air blower; ⑦process is optimized to reduce cooling water requirement; ?the heat exchange process is optimized to improve the quality of steam and increase steam flowrate; ⑨ hydraulic turbine is installed to recovery energy

  20. High-resolution electron tomography study of an industrial Ni-Mo/gamma-Al2O3 hydrotreating catalyst.

    Science.gov (United States)

    de Jong, Krijn P; van den Oetelaar, Leon C A; Vogt, Eelco T C; Eijsbouts, Sonja; Koster, Abraham J; Friedrich, Heiner; de Jongh, Petra E

    2006-06-01

    The growing demand for high-quality transportation fuels requires their cost-effective production by hydrodesulfurization of crude oils using heterogeneous catalysts. To study the three-dimensional (3D) structure of such a commercial, sulfided Ni-Mo/gamma-Al2O3 catalyst, electron tomography was applied. The MoS2 particles form an interconnected complex structure within the mesopores of the alumina support. Spatial organization, morphology, and orientation of the MoS2 particles in the pores were resolved with sufficient accuracy to display the 6-A-spaced MoS2 crystal planes. The proximity of the MoS2 edge planes and more loosely interacting MoS2 basal planes to the alumina support showed the presence of pores smaller than 3 nm, which was confirmed by physisorption experiments. The actual shape of the MoS2 particles cannot be described by simple models as derived from studies on model catalysts. Electron tomography is a unique tool to study the actual 3D structure of complex industrial catalysts with sub-nanometer resolution.

  1. 德兴铜矿HDS底泥回用的试验研究%Experimental Study on HDS Sediment Reuse in Dexing Copper Mine

    Institute of Scientific and Technical Information of China (English)

    严思明; 兰秋平

    2015-01-01

    与石灰乳相比,采用HDS底泥调节化学硫化技术除铁工艺pH,可以提高铜回收率和三价铁离子去除率;铜回收工艺,硫氢化钠用量少,且铜总回收率也相对较高;HDS工艺,虽然石灰乳用量偏大,但是从整个工艺来看,每升酸性水少用石灰乳5~6g,并且相同的铜上清液,添加HDS底泥比不添加要少用石灰乳1g多(约减少5%的石灰乳用量)。废水处理很少采用分段法,即用后段的底泥作为碱源调节前段的pH,降低石灰用量,来达到降低处理成本的目的。这样既减少石灰用量,又使底泥得到回用,带来了良好的经济效益。%compared with the lime, the iron removal process which used HDS sediment adjusting application could increased the copper recovery rate and trivalent iron ions removal rate;, with small amount sodium hydrosulfide was used in the copper recovery process, and the general recovery rate of copper was relatively higher;In the HDS process, although large amount of lime was used, but based on the entire process, e less 5-6g acidic lime was used in each liter of water; and in the same copper supernatant, the lime consumption in HDS sediment added was 1g less than non-HDS sediment added (around 5%reduction of lime consumption). Segmentation method was seldom used wastewater treatment, which used end stage sediment to adjust the preceding pH, reduce the lime consumption, to achieve lower processing costs. This process could reduce the lime consumption, and the sediment could be reused, good economic benefits were achieved.

  2. Catalyst Architecture

    DEFF Research Database (Denmark)

    the projects as case studies, which contribute with strategic knowledge rather than generalizing from average considerations. These are ‘strategic projects’ where we have looked for the specific and the particular (Flyvbjerg 1991). According to the case studies, we use the case study method developed by Bent......’ interpretations and architectural strategies are included in the analyses. This implies that there is a large variation of empirical knowledge about the selected problems. That is the reason why we give a short introduction to the exact use of approaches and methods in the beginning of each case study. Based...... in experience? Which design qualities do the best examples of architecture as urban catalysts have, and how can we as citizens, politicians and professionals use knowledge about this in the development of our cities as good places to live? We wish to throw light on these key questions through case studies...

  3. HDS.Journal

    OpenAIRE

    2014-01-01

    Den Kern der aktuellen Ausgabe bilden die Werkstattberichte geförderter Lehr-Lern-Projekte aus der 4. Kohorte. Diese präsentieren sich enorm vielfältig – sowohl in Inhalt als auch in gewählter Darstellungsform.

  4. Electrochemical catalyst recovery method

    Science.gov (United States)

    Silva, Laura J.; Bray, Lane A.

    1995-01-01

    A method of recovering catalyst material from latent catalyst material solids includes: a) combining latent catalyst material solids with a liquid acid anolyte solution and a redox material which is soluble in the acid anolyte solution to form a mixture; b) electrochemically oxidizing the redox material within the mixture into a dissolved oxidant, the oxidant having a potential for oxidation which is effectively higher than that of the latent catalyst material; c) reacting the oxidant with the latent catalyst material to oxidize the latent catalyst material into at least one oxidized catalyst species which is soluble within the mixture and to reduce the oxidant back into dissolved redox material; and d) recovering catalyst material from the oxidized catalyst species of the mixture. The invention is expected to be particularly useful in recovering spent catalyst material from petroleum hydroprocessing reaction waste products having adhered sulfides, carbon, hydrocarbons, and undesired metals, and as well as in other industrial applications.

  5. Modeling of a three-phase reactor for bitumen-derived gas oil hydrotreating

    Directory of Open Access Journals (Sweden)

    R. Chacón

    2012-03-01

    Full Text Available A three-phase reactor model for describing the hydrotreating reactions of bitumen-derived gas oil was developed. The model incorporates the mass-transfer resistance at the gas-liquid and liquid-solid interfaces and a kinetic rate expression based on a Langmuir-Hinshelwood-type model. We derived three correlations for determining the solubility of hydrogen (H2, hydrogen sulfide (H2S and ammonia (NH3 in hydrocarbon mixtures and the calculation of the catalyst effectiveness factor was included. Experimental data taken from the literature were used to determine the kinetic parameters (stoichiometric coefficients, reaction orders, reaction rate and adsorption constants for hydrodesulfuration (HDS and hydrodenitrogenation (HDN and to validate the model under various operating conditions. Finally, we studied the effect of operating conditions such as pressure, temperature, LHSV, H2/feed ratio and the inhibiting effect of H2S on HDS and NH3 on HDN.

  6. Foundation Flash Catalyst

    CERN Document Server

    Goralski, Greg

    2010-01-01

    This book offers an introduction to Flash Catalyst for designers with intermediate to advanced skills. It discusses where Catalyst sits within the production process and how it communicates with other programs. It covers all of the features of the Flash Catalyst workspace, teaching you how to create designs from scratch, how to build application designs and add functionality, and how to master the Catalyst/Flex workflow. * Introduces Flash Catalyst * Focuses on production process * Covers the interrelation between Flash Catalyst and Photoshop/Illustrator/Flex/Flash What you'll learn Starting f

  7. Characterization of hydro-treating catalysts through model reactions and infrared spectroscopy: contribution to the understanding of the working catalyst on real feed; Caracterisation de catalyseurs d'hydrotraitement par reactions modeles et spectroscopie infrarouge: apport a la comprehension du fonctionnement sur charge reelle

    Energy Technology Data Exchange (ETDEWEB)

    Dujardin, Ch.

    2002-07-01

    The activity of commercial CoMo/(P)Al{sub 2}O{sub 3} hydro-treating catalysts for a gas-oil feed has been compared to that obtained for model molecules, thiophene and 2,6-dimethyl-aniline. Thiophene reaction at atmospheric pressure does not distinguish the catalysts with or without phosphorus. The reaction scheme for 2.6-dimethyl-aniline under hydrogen pressure has been established on a series of catalysts promoted with various cobalt contents. It presents three parallel routes: de-aromatization followed by either hydrogenation-elimination to dimethyl-cyclohexane or elimination to xylene, and disproportionation. We evidenced also a direct denitrogenation reaction contributing to the formation of xylene. This process is enhanced by phosphorus. We showed that the hydrogenation route is nicely correlated with the activity for hydro-desulfurization of the gas-oil feed on the catalysts containing or not phosphorus. Moreover: the fraction of xylene produced by direct denitrogenation can be related to the hydrogenation of the poly-aromatic compounds of the gas-oil. The catalytic sites have been identified by carbon monoxide adsorption at 100 K followed by infrared spectroscopy on the catalysts sulfided in situ under flow. The adsorption distinguishes the coordinative unsaturated sulfur sites of the un-promoted and cobalt promoted molybdenum atoms. Theses sites are responsible for the de-aromatization step of 2.6-dimethyl-aniline. The sulfided catalyst exhibits about half of the potential sites expected from the geometrical mode] of the molybdenum disulfide slabs. Post-treating the sulfide catalyst by hydrogen creates highly unsaturated sites, specifically attached to the un-promoted molybdenum atoms, and associated to the activity of the catalyst for direct denitrogenation. The phosphorus doped catalysts require high hydrogen pressure to generate theses sites. (author)

  8. Carburos de Cobalto-Molibdeno soportados sobre carbón activado: efecto del método de síntesis, velocidad de calentamiento, tipo de precursor de cobalto y agente presulfurante en la hidrodesulfuración de tiofeno/Activated carbon supported cobalt-molybdenum carbides: effect of the synthesis method, heating rate, type of cobalt precursor and presulfiding agent on thiophene hydrodesulfurization

    National Research Council Canada - National Science Library

    Esneyder Puello-Polo; Mónica V Ayala; Joaquín L Brito

    2014-01-01

      This work studied the effect of the presulfiding agent, type of precursor, synthesis method and heating rate in the hydrodesulfurization of thiophene over activated carbon supported cobalt-molybdenum carbides...

  9. Design of heterogeneous catalysts

    DEFF Research Database (Denmark)

    Frey, Anne Mette

    was inspired by a computational screening, suggesting that alloys such as Ni-Fe, Co-Ni, and Co-Fe should show superior activity to the industrially used nickel catalyst. Especially the Ni-Fe system was considered to be interesting, since such alloy catalysts should be both more active and cheaper than the Ni...... well, and the best catalyst prepared had a C5+ yield almost a factor of two higher than a standard air calcined Co catalyst. In the NH3-SCR reaction it is desirable to develop an active and stable catalyst for NOx removal in automotive applications, since the traditionally used vanadium-based catalyst...... pose an environmental risk. The focus was put on iron-containing zeolite catalysts, since these recently have shown great potential as catalysts for the process. A number of different zeolites were compared. BEA was found to be the most active, thus focus was put on this material. Different preparation...

  10. A kinetic study on non-catalytic reactions in hydroprocessing Boscan crude oil

    Energy Technology Data Exchange (ETDEWEB)

    A. Marafi; E. Kam; A. Stanislaus [Kuwait Institute for Scientific Research, Safat (Kuwait). Petroleum Refining Department, Petroleum Research and Studies Center

    2008-08-15

    Non-catalytic hydrothermal cracking reactions are known to associate with catalytic hydrocracking reactions. In a recent study on hydroprocessing of Boscan crude over a specific catalyst system containing three distinct catalysts, it was found that hydrodesulfurization (HDS) and hydrodemetallation (HDM) reactions continued even when the catalyst is severely deactivated. Since the reactor was packed with considerable amount of inert material besides the three catalysts, it will be advantage to determine if the inert materials can also facilitate hydroprocessing reactions. A series of kinetic experiments for the inert particles was undertaken under different space velocity and temperature conditions. The extent of catalytic and non-catalytic hydroprocessing reactions was assessed. Through statistical analysis, the initial reaction rate constant, reaction order and activation energy for various hydroprocessing reactions were then determined. The absolute average deviations (AAD) of the kinetics values obtained for inert materials are less than 10%. 25 refs., 7 figs., 4 tabs.

  11. Significance of the compensation effect and the definition of active centres in metal catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Bond, G.C.

    1985-01-01

    A linear correlation is often observed between the activation energy and the logarithm of the pre-exponential factor in catalysed reactions, although the root cause of this so-called compensation effect is still uncertain. Certain systems exhibit dual or multiple compensation lines, and it is argued that each line corresponds to a particular form of active centre; in monometallic systems each form is thought to have the same number of atoms in the same spatial arrangement. This concept is applied both to simple reactions yielding only one product (e.g. CO methanation, C/sub 2/H/sub 6/ hydrogenolysis) and to reactions forming a variety of products (e.g. cyclopropane hydrogenation), and also to sulphide catalysts for thiophene HDS.

  12. Pd Close Coupled Catalyst

    Institute of Scientific and Technical Information of China (English)

    Zhong Hua SHI; Mao Chu GONG; Yao Qiang CHEN

    2006-01-01

    A catalyst comprised novel high surface area alumina support was prepared to control emission of automobiles. The results showed that prepared catalyst could satisfy the requirements of a high performance close coupled catalyst for its good catalytic activity at low temperature and good stability at high temperature.

  13. Long-term remission in mantle cell lymphoma following high-dose sequential chemotherapy and in vivo rituximab-purged stem cell autografting (R-HDS regimen).

    Science.gov (United States)

    Gianni, Alessandro M; Magni, Michele; Martelli, Maurizio; Di Nicola, Massimo; Carlo-Stella, Carmelo; Pilotti, Silvana; Rambaldi, Alessandro; Cortelazzo, Sergio; Patti, Caterina; Parvis, Guido; Benedetti, Fabio; Capria, Saveria; Corradini, Paolo; Tarella, Corrado; Barbui, Tiziano

    2003-07-15

    Mantle cell lymphoma (MCL) is rarely cured with standard-dose chemotherapy. From January 1997 to February 2000, 28 previously untreated advanced-stage MCL patients younger than 61 years of age were treated at 9 Italian hematologic departments with 3 cycles of standard-dose debulking chemotherapy followed by a high-dose rituximab-supplemented sequence (R-HDS) including intravenous administration of high-dose cyclophosphamide, high-dose cytarabine, high-dose melphalan, and high-dose mitoxantrone plus melphalan. Study end points included toxicity, clinical and molecular response rates, long-term event-free survival (EFS), and overall survival (OS) rates, as well as the ability to harvest tumor-free peripheral blood stem cells. Optimal amounts of polymerase chain reaction-negative (PCR-negative) CD34+ cells were collected from all 20 informative patients. One patient died of toxicity. All 27 patients assessable for response achieved a complete response (CR), of which 24 remain in continuous complete remission (CCR) after a median follow-up of 35 months. Three patients had transient evidence of PCR-detectable disease in the bone marrow. The OS and EFS rates at 54 months were 89% and 79%, respectively. These results compare with the 42% OS rate and the 18% EFS rate observed in 35 age-matched historic controls treated with standard-dose chemotherapy at the participating centers. The use of rituximab in combination with high-dose chemotherapy represents a very effective in vivo purging method. The R-HDS regimen can be safely applied in a multicenter hematology setting and leads to long-term EFS and OS in the majority of patients with an otherwise incurable disease.

  14. El principio del BEP en la catálisis heterogénea de la reacción de HDS: caso de los sistemas catalíticos constituidos por sulfuros de metales de transición másicos

    Directory of Open Access Journals (Sweden)

    Iván Manchín

    2012-12-01

    Full Text Available A new thermodynamic parameter is defined as a descriptor of the energy of the metal-sulfide bond. This parameter enables a linear correlation with the natural logarithm of the HDS activity. The linear correlation obtained reaffirms that those descriptors that account properly for the energy of metal-sulfur bond will tend to generate higher quality linear correlations with the catalytic activity. This result supports those kinetic models where the decisive step in the HDS process is associated with the rupture of metal-sulfur bond. This study raises the conjecture of the possible existence of transient active phases responsible for the catalysis of HDS process.

  15. Kinetics and mechanism of desulfurization and denitrogenation of coal-derived liquids. Second quarterly report, September 20, 1975--December 20, 1975. [Aged CoO-MoO/sub 3/-SiO/sub 2/-Al/sub 2/O/sub 3/ catalyst pellets used in single-stage liquefaction and hydrosulfurization of coal

    Energy Technology Data Exchange (ETDEWEB)

    Katzer, J. R.; Gates, B. C.; Olson, J. H.; Kwart, H.; Stiles, A. B.

    1976-01-08

    The construction of the first high-pressure liquid-phase flow microreactor has been completed, and kinetic studies of reaction of dibenzothiophene have been started. Understanding of catalytic hydrodesulfurization and catalyst decay has been advanced by examination of the reaction rate of thiophene, tetrahydrothiophene, and butanethiol on Harshaw 0402T catalyst. Two batch autoclave reactors have been completely assembled behind appropriate safety barricades; satisfactory operation has been demonstrated; and quinoline hydrodenitrogenation studies are underway to demonstrate operating procedures providing quantitative, reproducible data. Quinoline rapidly hydrogenates to tetrahydroquinoline; the two compounds appear to be in thermodynamic equilibrium. The tetrahydroquinoline apparently undergoes slow hydrogenolysis of the nitrogen-containing ring giving n-propylaniline as an identified long-lived product. The reaction engineering of the pulsed microreactor system has been developed and compared to some laboratory data. The moments of the inlet and exit pulses show substantial effects from product adsorption.

  16. Synthesis of catalysts supported in {gamma}-alumina; Sintese de catalisadores suportados na {gamma}-alumina

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Luiza Gabriel; Silva, A.J.N.; Santos, I.M.G.; Souza, A.G. [Paraiba Univ, Joao Pessoa, PB (Brazil). Dept. de Quimica. Lab. de Termoquimica e Materiais]. E-mail: luizagaby@yahoo.com.br; Fernandes Junior, V.J.; Araujo, A.S. [Rio Grande do Norte Univ., Natal, RN (Brazil). Dept. de Quimica. Lab. de Combustiveis

    2003-07-01

    Fuels contain a great amount of undesirable pollutants as asphaltenes, metals, sulfides and nitrogen compounds. The content of sulfur in petroleum is around 1%,. When burned, fuels liberate SO{sub x}, the greatest air pollutant . The maximum sulfur quantity in diesel is {approx}350 wppm, but in agreement to European specifications, this content will fall to 50 wppm up to 2005. To remove this sulfur a deep hydrodesulfurization is necessary, requiring high performance catalysts. This way, in this work, the following catalysts were synthesized, using Pechini method: MoO{sub 3} containing Ni and/or Co supported on {gamma}-alumina, with the formulas Co{sub x}Mo{sub 1-x}O{sub 3}/Al{sub 2}O{sub 3}, Ni{sub x}Mo{sub 1-x}O{sub 3}/Al{sub 2}O{sub 3} and Ni{sub x/2}Co{sub x/2}Mo{sub 1-x}O{sub 3}/Al{sub 2}O{sub 3} where x 0,01, 0,02 and 0,03 in mol percentage. This method was proposed, due to its high stoichiometry control, purity, reproducibility and homogeneity. All catalysts were submitted to thermal treatment at 500 deg C to 700 deg C and characterized by thermogravimetry, infrared spectroscopy, X-ray diffraction. Results indicate the stabilization of the requested composition at around 622 deg C. The X-ray diffraction results indicate that secondary phase increases with dopant amount. (author)

  17. Catalyst Alloys Processing

    Science.gov (United States)

    Tan, Xincai

    2014-10-01

    Catalysts are one of the key materials used for diamond formation at high pressures. Several such catalyst products have been developed and applied in China and around the world. The catalyst alloy most widely used in China is Ni70Mn25Co5 developed at Changsha Research Institute of Mining and Metallurgy. In this article, detailed techniques for manufacturing such a typical catalyst alloy will be reviewed. The characteristics of the alloy will be described. Detailed processing of the alloy will be presented, including remelting and casting, hot rolling, annealing, surface treatment, cold rolling, blanking, finishing, packaging, and waste treatment. An example use of the catalyst alloy will also be given. Industrial experience shows that for the catalyst alloy products, a vacuum induction remelt furnace can be used for remelting, a metal mold can be used for casting, hot and cold rolling can be used for forming, and acid pickling can be used for metal surface cleaning.

  18. Resin Catalyst Hybrids

    Institute of Scientific and Technical Information of China (English)

    S. Asaoka

    2005-01-01

    @@ 1Introduction: What are resin catalyst hybrids? There are typically two types of resin catalyst. One is acidic resin which representative is polystyrene sulfonic acid. The other is basic resin which is availed as metal complex support. The objective items of this study on resin catalyst are consisting of pellet hybrid, equilibrium hybrid and function hybrid of acid and base,as shown in Fig. 1[1-5].

  19. Structure, energetics, and electronic properties of the surface of a promoted MoS{sub 2} catalyst: An ab initio local density functional study

    Energy Technology Data Exchange (ETDEWEB)

    Raybaud, P.; Hafner, J.; Kresse, G.; Kasztelan, S.; Toulhoat, H.

    2000-02-15

    The determination of the local structure of cobalt- or nickel-promoted MoS{sub 2}-based hydrodesulfurization catalysts is of interest for understanding the mechanism leading to an increased activity brought by cobalt or nickel, the so-called synergetic effect. For that reason, the authors carried out ab initio calculations using density functional theory under the generalized gradient approximation for periodic systems. The edge substitution model emerges as the most stable structure and provides an excellent agreement with local structures experimentally determined on real catalysts by in situ extended X-ray absorption fine structure. The authors studied the absorption of sulfur on the active edge surface of the promoted MoS{sub 2} catalyst and determined the equilibrium coverage under sulfiding conditions. It is demonstrated that the incorporation of promoter atoms has a strong influence on the sulfur-metal bond energy at the surface and in particular leads to a reduction of the equilibrium S coverage of the active metal sites. A comparative study on the effects of Co, Ni, and Cu atoms as promoters was performed. Detailed results on the surface electronic structure of promoted MoS{sub 2} are presented.

  20. Combustion characteristics of spent catalyst and paper sludge in an internally circulating fluidized-bed combustor.

    Science.gov (United States)

    Roh, Seon Ah; Jung, Dae Sung; Kim, Sang Done; Guy, Christophe

    2005-09-01

    Combustion of spent vacuum residue hydrodesulfurization catalyst and incineration of paper sludge were carried out in thermo-gravimetric analyzer and an internally circulating fluidized-bed (ICFB) reactor. From the thermo-gravimetric analyzer-differential thermo-gravimetric curves, the pre-exponential factors and activation energies are determined at the divided temperature regions, and the thermo-gravimetric analysis patterns can be predicted by the kinetic equations. The effects of bed temperature, gas velocity in the draft tube and annulus, solid circulation rate, and waste feed rate on combustion efficiency of the wastes have been determined in an ICFB from the experiments and the model studies. The ICFB combustor exhibits uniform temperature distribution along the bed height with high combustion efficiency (>90%). The combustion efficiency increases with increasing reaction temperature, gas velocity in the annulus region, and solid circulation rate and decreases with increasing waste feed rate and gas velocity in the draft tube. The simulated data from the kinetic equation and the hydrodynamic models predict the experimental data reasonably well.

  1. Magnetic catalyst bodies

    NARCIS (Netherlands)

    Teunissen, Wendy; Bol, A.A.; Geus, John W.

    2001-01-01

    After a discussion about the importance of the size of the catalyst bodies with reactions in the liquid-phase with a suspended catalyst, the possibilities of magnetic separation are dealt with. Deficiencies of the usual ferromagnetic particles are the reactivity and the clustering of the particles.

  2. External Catalyst Breakup Phenomena

    Science.gov (United States)

    1976-06-01

    14-18 Mesh Catalyst 127 4-12 Hot Gas Thermal Fatigue Test Results for 25-30 Mesh Catalyst 128 4-13 Hot Gas Thermal Aging Test Results 131 - 19 - LISI ...magnitude of the thermal and internal pressure solution3, These solucions siu- Li.L fti’r oir =ztcrii ad the pressure and temperature profiles of

  3. Catalyst for Ammonia Oxidation

    DEFF Research Database (Denmark)

    2015-01-01

    The present invention relates to a bimetallic catalyst for ammonia oxidation, a method for producing a bimetallic catalyst for ammonia oxidation and a method for tuning the catalytic activity of a transition metal. By depositing an overlayer of less catalytic active metal onto a more catalytic...

  4. Reducible oxide based catalysts

    Science.gov (United States)

    Thompson, Levi T.; Kim, Chang Hwan; Bej, Shyamal K.

    2010-04-06

    A catalyst is disclosed herein. The catalyst includes a reducible oxide support and at least one noble metal fixed on the reducible oxide support. The noble metal(s) is loaded on the support at a substantially constant temperature and pH.

  5. Alloy catalyst material

    DEFF Research Database (Denmark)

    2014-01-01

    The present invention relates to a novel alloy catalyst material for use in the synthesis of hydrogen peroxide from oxygen and hydrogen, or from oxygen and water. The present invention also relates to a cathode and an electrochemical cell comprising the novel catalyst material, and the process use...

  6. Bioinformatics Analysis of 4-hydroxy-3-methyl-2- buten1yl diphosphate synthase (HDS) in Populus trichocarpa%毛果杨1-羟基-2-甲基-2-(E)-丁烯基-4-二磷酸合酶(HDS)基因的生物信息学分析

    Institute of Scientific and Technical Information of China (English)

    刘立辉; 李成浩; 杨静莉; 夏德安

    2012-01-01

    [目的]研究HDS基因间的同源性及其进化关系.[方法]以毛果杨的HDS基因为研究对象,利用生物信息学软件及网站对其进行碱基分布、氨基酸组成、亲疏水性、保守区以及二级结构和三级结构的预测与分析.,并与其他10个物种的HDS基因序列进行多重比对与进化分析.[结果]毛果杨HDS基因的单链mRNA序列长1 956 bp,编码由656个氨基酸组成的蛋白质,该蛋白质相对分子质量为72 937.03,其中含量最高的是Leu,为10.50%;整个多肽中疏水性氨基酸只占39.63%,有10个亲水区和6个疏水区;与其他10个物种同源性多重比对发现同源性最高达99%.[结论]毛果杨HDS基因处于稳定状态,编码的蛋白为亲水性蛋白,在进化过程中是保守的;试验中获得的保守区段序列信息为新基因的克隆奠定了基础.%[ Objective] The aim was to study the homology and evolutionary relationship among HAD genes. [ Method] Based on HDS gene of Populus trichocarpa, bioinformatics software and website were used to predict and analyze base distribution, amino acids composition, hydrophil-city or hydrophobicity, hyperconservative region, secondary structure, and three-level structure. The results were used to compare with HDS gene sequences of other ten species and related evolution analysis was followed. [ Result ] mRNA, single chain of HDS gene of Populus trichocarpa , was 1 956 bp in length, code was made up of proteins containing amino acids of 656, and relative molecular mass of protein was 72 937.03 with Leu of 10. 50% involume; in polypeptide, hydrophobic amino acid was only of 39.63% with hydrophilc region of 10 and hy-drophobic region of 6; after many comparisons with other ten species, homology was found as high as 99%. [ Conclusion ] HDS gene of Populus trichocarpa was quite stable and coded albumen was hydrophilic protein which was quite conservative in evolution; sequence information in conservative region gained in the

  7. Chemical composition of carbon-rich, very metal-poor subgiant LP625-44 observed with the Subaru/HDS

    CERN Document Server

    Aoki, W; Honda, S; Iye, M; Izumiura, H; Kajino, T; Kambe, E; Kawanomoto, S; Noguchi, K; Okita, K; Sadakane, K; Sato, B; Shelton, I; Takada-Hidai, M; Takeda, Y; Watanabe, E; Yoshida, M

    2002-01-01

    We have obtained a high resolution (R~90,000) spectrum of the carbon- and s-process-element-rich, very metal-poor ([Fe/H]=-2.7) subgiant LP625-44, as well as that of HD140283 (a metal-poor subgiant with normal abundance ratio) for comparison, with the High Dispersion Spectrograph (HDS) for the Subaru Telescope for detailed abundance study. The oxygen abundance derived from the O I triplet around 7770A is uncertain, but the excess of oxygen in LP625-44 seems remarkable (perhaps by nearly a factor 10), in comparison with that of HD140283 derived from the same lines. The Na enhancement in LP625-44 is by about a factor 50, suggesting hydrogen burning in the 22Ne-rich layer in an asymptotic giant branch star which produces the abundance pattern of this object. In our new spectrum of LP625-44, the Pb I lambda 3683A line has been detected, as well as the Pb I lambda 4057A line which has already been studied, confirming the Pb abundance (log epsilon(Pb)~1.9) derived by the previous work. The abundance ratio of s-proc...

  8. Density functional study of the adsorption and van der Waals binding of aromatic and conjugated compounds on the basal plane of MoS2

    DEFF Research Database (Denmark)

    Moses, Poul Georg; Mortensen, Jens Jørgen; Lundqvist, Bengt;

    2009-01-01

    Accurate calculations of adsorption energies of cyclic molecules are of key importance in investigations of, e.g., hydrodesulfurization (HDS) catalysis. The present density functional theory (DFT) study of a set of important reactants, products, and inhibitors in HDS catalysis demonstrates that v...

  9. Catalysts, methods of making catalysts, and methods of use

    KAUST Repository

    Renard, Laetitia

    2014-03-06

    Embodiments of the present disclosure provide for catalysts, methods of making catalysts, methods of using catalysts, and the like. In an embodiment, the method of making the catalysts can be performed in a single step with a metal nanoparticle precursor and a metal oxide precursor, where a separate stabilizing agent is not needed.

  10. Catalyst in Basic Oleochemicals

    Directory of Open Access Journals (Sweden)

    Eva Suyenty

    2007-10-01

    Full Text Available Currently Indonesia is the world largest palm oil producer with production volume reaching 16 million tones per annum. The high crude oil and ethylene prices in the last 3 – 4 years contribute to the healthy demand growth for basic oleochemicals: fatty acids and fatty alcohols. Oleochemicals are starting to replace crude oil derived products in various applications. As widely practiced in petrochemical industry, catalyst plays a very important role in the production of basic oleochemicals. Catalytic reactions are abound in the production of oleochemicals: Nickel based catalysts are used in the hydrogenation of unsaturated fatty acids; sodium methylate catalyst in the transesterification of triglycerides; sulfonic based polystyrene resin catalyst in esterification of fatty acids; and copper chromite/copper zinc catalyst in the high pressure hydrogenation of methyl esters or fatty acids to produce fatty alcohols. To maintain long catalyst life, it is crucial to ensure the absence of catalyst poisons and inhibitors in the feed. The preparation methods of nickel and copper chromite catalysts are as follows: precipitation, filtration, drying, and calcinations. Sodium methylate is derived from direct reaction of sodium metal and methanol under inert gas. The sulfonic based polystyrene resin is derived from sulfonation of polystyrene crosslinked with di-vinyl-benzene. © 2007 BCREC UNDIP. All rights reserved.[Presented at Symposium and Congress of MKICS 2007, 18-19 April 2007, Semarang, Indonesia][How to Cite: E. Suyenty, H. Sentosa, M. Agustine, S. Anwar, A. Lie, E. Sutanto. (2007. Catalyst in Basic Oleochemicals. Bulletin of Chemical Reaction Engineering and Catalysis, 2 (2-3: 22-31.  doi:10.9767/bcrec.2.2-3.6.22-31][How to Link/DOI: http://dx.doi.org/10.9767/bcrec.2.2-3.6.22-31 || or local: http://ejournal.undip.ac.id/index.php/bcrec/article/view/6

  11. ALKALI RESISTANT CATALYST

    DEFF Research Database (Denmark)

    2008-01-01

    The present invention concerns the selective removal of nitrogen oxides (NOx) from gasses. In particular, the invention concerns a process, a catalyst and the use of a catalyst for the selective removal of nitrogen oxides in the presence of ammonia from gases containing a significant amount...... of alkali metal and/or alkali-earth compounds which process comprises using a catalyst combined of (i) a formed porous superacidic support, said superacidic support having an Hammett acidity stronger than Ho=-12, and (ii) a metal oxide catalytic component deposited on said superacidic support selected from...

  12. The role of transition metal sulfides in hydrotreatment. 3. Acidity, XPS and catalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    De Agudelo, M.M.; Reyes, L.G.; Do Campo, N.

    1987-05-15

    Although, recently, most of the research on catalysis has been devoted to hydrotreatment, attention has been paid to hydrodesulfurization (HDS) but very little has been done on hydrodemetallization (HDM). This article is part of a systematic study directed towards defining the role of transition metal sulfides in hydrotreatment reactions. Catalysts supported on silica or alumina have been considered. Acidity has been evaluated using pyridine as probe molecule. This property can be attributed to the sulfide phase of the catalysts. The alumina supported catalysts were more acid than the silica supported catalysts. Since the acidity might exclusively be of Lewis type, the pattern observed through the first row transition metal sulfides reflects the trend of the electron-acceptor character of these sulfides. The XPS results indicate that catalysts are partially sulfided (at 400 C). At the same time, the results corroborate a better Me-support interaction on alumina than on silica. The HDM and HDS intrinsic activities, using a desalphalted (DAO) Morichal as feed were evaluated normalizing conversion in terms of the surface metal sites per surface area. The intrinsic activity patterns obtained for the first row transition metal sulfides, were very similar to those mentioned of acidity, reaffirming the importance of the electronic structure of the sulfide phase on its catalytic activity. 21 refs.

  13. Catalyst for microelectromechanical systems microreactors

    Science.gov (United States)

    Morse, Jeffrey D.; Sopchak, David A.; Upadhye, Ravindra S.; Reynolds, John G.; Satcher, Joseph H.; Gash, Alex E.

    2010-06-29

    A microreactor comprising a silicon wafer, a multiplicity of microchannels in the silicon wafer, and a catalyst coating the microchannels. In one embodiment the catalyst coating the microchannels comprises a nanostructured material. In another embodiment the catalyst coating the microchannels comprises an aerogel. In another embodiment the catalyst coating the microchannels comprises a solgel. In another embodiment the catalyst coating the microchannels comprises carbon nanotubes.

  14. Epoxidation catalyst and process

    Science.gov (United States)

    Linic, Suljo; Christopher, Phillip

    2010-10-26

    Disclosed herein is a catalytic method of converting alkenes to epoxides. This method generally includes reacting alkenes with oxygen in the presence of a specific silver catalyst under conditions suitable to produce a yield of the epoxides. The specific silver catalyst is a silver nanocrystal having a plurality of surface planes, a substantial portion of which is defined by Miller indices of (100). The reaction is performed by charging a suitable reactor with this silver catalyst and then feeding the reactants to the reactor under conditions to carry out the reaction. The reaction may be performed in batch, or as a continuous process that employs a recycle of any unreacted alkenes. The specific silver catalyst has unexpectedly high selectivity for epoxide products. Consequently, this general method (and its various embodiments) will result in extraordinarily high epoxide yields heretofore unattainable.

  15. Influence of air annealing temperature and time on the optical properties of Yb:YAG single crystal grown by HDS method

    Science.gov (United States)

    Nie, Ying; Liu, Yang; Zhao, Yequan; Zhang, Mingfu

    2015-08-01

    8 at.% Yb:YAG plate single crystal with the dimension of 170 mm × 150 mm × 30 mm was grown in vacuum by Horizontal Directional Solidification method. Aimed at blue-green color centers, annealing treatments of 15 mm × 15 mm × 1 mm samples from 900 °C to 1400 °C for 5 h and at 900 °C from 5 h to 40 h in air were conducted. The absorption spectra, emission spectra, fluorescence lifetime and X-ray photoelectron spectroscopy of samples under different annealing conditions were measured at room temperature, respectively. Annealing at above 1000 °C for 5 h or at 900 °C for 40 h made the blue-green color centers disappear and the samples turned to transparent. Absorption coefficients decreased in the 300 nm-800 nm wavelength range, emission intensities increased and emission bands broadened around 486 nm and 1029 nm with increasing temperature up to 1200 °C, then varied inversely. These values decreased or increased monotonically with increasing annealing time at 900 °C. The maximal increases of fluorescence lifetime were 62.3% and 64.7%, respectively. The calculated emission cross section of 1200 °C for 5 h was up to 4.4 × 10-20 cm2. In X-ray photoelectron spectroscopy, the concentrations of oxygen vacancies reduced from 1.28% down to absence by annealing. These experiments show that color centers are detrimental to the optical properties of HDS-Yb:YAG laser crystal and optimal annealing treatments should be conducted.

  16. New Catalysts for ROMP

    Institute of Scientific and Technical Information of China (English)

    H. Berke; C. Frech; A. Lhamazares; O. Blacque; H.W. Schmalle; C. Adlhart; P. Chen

    2005-01-01

    @@ 1Introduction Ring Opening Metathesis Polymerization (ROMP) is based on the olefin metathesis reaction, which requires transition metal catalysts. Mainly molybdenum, tungsten and ruthenium based catalysts have up to now been used. The "in-between" metal rhenium was only rarely applied in olefin metathesis reactions, and not at all in ROMP processes.We have found that cationic phosphine substituted dinitrosyl rhenium complexes[1]1a and 1b effectively catalyze ROMP of norbonene, dicyclopentadiene and of cyclooctene. See Fig. 1.

  17. In-situ HRTEM study of the reactive carbide phase of Co/MoS{sub 2} catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Ramos, Manuel, E-mail: manuel.ramos@uacj.mx [Departamento de Física y Matemáticas, Instituto de Ingeniería y Tecnología, UACJ, 32310 Ciudad Juárez, México (Mexico); Materials Research and Technology Institute, UT-El Paso, El Paso, TX 79902 (United States); Ferrer, Domingo [Microelectronics Research Laboratory, UT-Austin, Austin, TX 78758 (United States); Martinez-Soto, Eduan [Departamento de Química, Universidad Metropolitana, San Juan, PR 00926-2602 (United States); Lopez-Lippmann, Hugo; Torres, Brenda [Materials Research and Technology Institute, UT-El Paso, El Paso, TX 79902 (United States); Berhault, Gilles [Institut de Recherches sur la Catalyse et l’Environnement, IRCELYON, CNRS, Université de Lyon, Villeurbanne 69100 (France); Chianelli, Russell R. [Materials Research and Technology Institute, UT-El Paso, El Paso, TX 79902 (United States)

    2013-04-15

    Hydrotreatment catalytic operations are commonly performed industrially by layered molybdenum sulfide promoted by cobalt or nickel in order to remove heteroelements (S, N, O) from fossil fuels and biofuels. Indeed, these heteroelements are responsible of the emission of pollutants when these fuels are used in vehicles. In this respect, previous studies made by our research group have shown that the active phase under steady state conditions is partially carbided while strong bending effects of MoS{sub 2} slabs were also observed. However, up to now, the morphology of the resulting Co/MoS{sub x}C{sub y} carbided catalyst has not been fully characterized. In the present study, for the first time, a chemical reaction between the carbon content of a TEM Cu/C grid and a freshly sulfide Co/MoS{sub 2} catalyst was in situ observed at 300 °C and 450 °C by HRTEM experimental techniques at ∼10 nm of resolution. Results indicate that bending of MoS{sub 2} layers occurred due to carbon addition on MoS{sub 2} edge sites, as observed in stabilized catalysts after HDS reaction. Using a silicon grid, only cracks of MoS{sub 2} slabs were observed without bending effect confirming the role of structural-carbon in this change of morphology.

  18. Light straight-run gas oil hydrotreatment over sulfided CoMoP/Al{sub 2}O{sub 3}-USY zeolite catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Marin, C.; Escobar, J.; Galvan, E.; Murrieta, F.; Zarate, R.; Vaca, H. [Instituto Mexicano del Petroleo, Tratamiento de Crudo Maya, Eje Central Lazaro Cardenas 152, Col. San Bartolo Atepehuacan, Del. G.A. Madero (Mexico)

    2005-01-25

    Al{sub 2}O{sub 3} supports were modified by integrating USY zeolites (13.6 wt.%) of various nominal SiO{sub 2}/Al{sub 2}O{sub 3} molar ratios (30-80). The obtained hybrid solids calcined at 500 {sup o}C were impregnated at incipient wetness with a Co-Mo-P solution. After sulfiding with CS{sub 2}-spiked naphtha (at 230 {sup o}C, 5.5 MPa and LHSV=3 h{sup -1}) the corresponding catalysts were tested in light straight-run gas oil hydrotreatment at industrially relevant operating conditions. The catalyst containing zeolite of the highest SiO{sub 2}/Al{sub 2}O{sub 3} molar ratio (80) showed very high hydrodesulfurization activity. Operating at 360 {sup o}C, 5.5 MPa and LHSV=2.5 h{sup -1}, ultra-low sulfur diesel (circa 50 ppm S) could be obtained over that material, from a feedstock of 10,400 ppm S. Medium-strong acidity could be playing an important role on this behaviour by promoting isomerization of sterically hindered organo-sulfur compounds to more favorable configurations. Moreover, hydrodearomatization and hydrodenitrogenation were also enhanced by addition of that high-silica zeolite.

  19. 直馏柴油催化氧化脱硫均相催化剂的制备与评价%Preparation and evaluation of desulfurization catalysts for homogeneous catalytic oxidation of straight-run diesel

    Institute of Scientific and Technical Information of China (English)

    唐晓东; 刘亮; 税蕾蕾

    2005-01-01

    Large investment, high operating cost and severe operation condition exist in the technology of diesel hydrodesulfurization, and the technology of H2O2 oxidative desulfurization of diesel has such problems as high oxidizer cost, oxidizer not regenerable, and treatment of sour water. A new catalytic oxidative desulfurization method for straight-run diesel is presented in this paper. In order to produce lowsulfur diesel, the sulfide in diesel oil was oxidized and converted into sulfone-polar sulfide with homogeneous catalysts and air oxidizer, and then removed by extractant. The homogenous catalysts were prepared by compound decomposition. The catalysts selected could dissolve in diesel at a given temperature and separate out at a lower temperature. The effects of catalytic oxidation of zinc benzoate, manganese benzoate and manganese phthalate were tested. The desulfurization effect of zinc benzoate and manganese benzoate was much better and the sulfur content of the desulfurized diesel met the standard of Eu Ⅱ diesel (<300μg·g-1 ).

  20. Supported organoiridium catalysts for alkane dehydrogenation

    Science.gov (United States)

    Baker, R. Thomas; Sattelberger, Alfred P.; Li, Hongbo

    2013-09-03

    Solid supported organoiridium catalysts, a process for preparing such solid supported organoiridium catalysts, and the use of such solid supported organoiridium catalysts in dehydrogenation reactions of alkanes is provided. The catalysts can be easily recovered and recycled.

  1. Mesoporous molecular sieve catalysts

    DEFF Research Database (Denmark)

    Højholt, Karen Thrane

    be used as solid acid catalysts but can also be used as a size-selective matrix. It was shown that it is possible to encapsulate 1-2 nm sized gold nanoparticles by silicalite-1 or ZSM-5 zeolite crystals thereby forming a sintering-stable and substrate size-selective oxidation catalyst. After carrying out...... calcination experiments, both in situ and ex situ indicated that the gold nanoparticles embedded in the crystals were highly stable towards sintering. The catalytic tests proved that the embedded gold nanoparticles were active in selective aldehyde oxidation and were only accessible through the micropores...

  2. Dynamics of Catalyst Nanoparticles

    DEFF Research Database (Denmark)

    Hansen, Thomas Willum; Cavalca, Filippo; Wagner, Jakob Birkedal

    under gas exposure, dynamic phenomena such as sintering and growth can be observed with sub-Ångstrøm resolution. Metal nanoparticles contain the active sites in heterogeneous catalysts, which are important for many industrial applications including the production of clean fuels, chemicals...... and pharmaceuticals, and the cleanup of exhaust from automobiles and stationary power plants. Sintering, or thermal deactivation, is an important mechanism for the loss of catalyst activity. In order to initiate a systematic study of the dynamics and sintering of nanoparticles, various catalytic systems have been...

  3. Aerogel derived catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Reynolds, J. G., LLNL

    1996-12-11

    Aerogels area class of colloidal materials which have high surface areas and abundant mesoporous structure. SiO{sub 2} aerogels show unique physical, optical and structural properties. When catalytic metals are incorporated in the aerogel framework, the potential exists for new and very effective catalysts for industrial processes. Three applications of these metal-containing SiO{sub 2} aerogels as catalysts are briefly reviewed in this paper--NO{sub x} reduction, volatile organic compound destruction, and partial oxidation of methane.

  4. Olefin metathesis catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Kukes, S.G.; Banks, R.L.

    1986-05-20

    A process is described for preparing a disproportionation catalyst comprising admixing a catalytically effective amount of a calcined and activated catalyst consisting essentially of at least one metal oxide selected from molybdenum oxide and tungsten oxide and a support containing a major proportion of silica or alumina with a promoting amount of a methylating agent selected from the group consisting of dimethyl sulfate, dimethylsulfoxide, trimethyloxonium tetrafluorborate, methyl iodide, and methyl bromide, and subjecting same to inert atmospheric conditions for the methylating agent to promote the activity of the calcined molybdenum and tungsten oxides for the disproportionation of olefins.

  5. Deactivation-resistant catalyst for selective catalyst reduction of NOx

    DEFF Research Database (Denmark)

    2011-01-01

    The present invention relates to a catalyst for selective catalytic reduction of NOx in alkali metal containing flue gas using ammonia as reductant, the catalyst comprising a surface with catalytically active sites, wherein the surface is at least partly coated with a coating comprising at least...... one metal oxide. In another aspect the present invention relates to the use of said catalyst and to a method of producing said catalyst. In addition, the present invention relates to a method of treating an catalyst for conferring thereon an improved resistance to alkali poisoning....

  6. Nanopore and nanoparticle catalysts.

    Science.gov (United States)

    Thomas, J M; Raja, R

    2001-01-01

    The design, atomic characterization, performance, and relevance to clean technology of two distinct categories of new nanocatalysts are described and interpreted. Exceptional molecular selectivity and high activity are exhibited by these catalysts. The first category consists of extended, crystallographically ordered inorganic solids possessing nanopores (apertures, cages, and channels), the diameters of which fall in the range of about 0.4 to about 1.5 nm, and the second of discrete bimetallic nanoparticles of diameter 1 to 2 nm, distributed more or less uniformly along the inner walls of mesoporous (ca. 3 to 10 nm diameter) silica supports. Using the principles and practices of solid-state and organometallic chemistry and advanced physico-chemical techniques for in situ and ex situ characterization, a variety of powerful new catalysts has been evolved. Apart from those that, inter alia, simulate the behavior of enzymes in their specificity, shape selectivity, regio-selectivity, and ability to function under ambient conditions, many of these new nanocatalysts are also viable as agents for effecting commercially significant processes in a clean, benign, solvent-free, single-step fashion. In particular, a bifunctional, molecular sieve nanopore catalyst is described that converts cyclohexanone in air and ammonia to its oxime and caprolactam, and a bimetallic nanoparticle catalyst that selectively converts cyclic polyenes into desirable intermediates. Nanocatalysts in the first category are especially effective in facilitating highly selective oxidations in air, and those in the second are well suited to effecting rapid and selective hydrogenations of a range of organic compounds.

  7. Heterogeneous chromium catalysts

    NARCIS (Netherlands)

    2005-01-01

    The present invention relates to a heterogeneous chromium catalyst system for the polymerisation of ethylene and/or alpha olefins prepared by the steps of: (a) providing a silica-containing support, (b) treating the silica-containing support with a chromium compound to form a chromium-based silica-c

  8. Olefin metathesis and catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Kukes, S. G.; Banks, R. L.

    1985-05-14

    Olefins are converted into other olefins having different numbers of carbon atoms by contact with a catalyst comprising an inorganic refractory oxide support containing at least one of tungsten oxide and molybdenum oxide and a promoting amount of at least one methylating agent under conditions suitable for the methylating agent compounds to promote the activity of tungsten and molybdenum oxides for the disproportionation reaction.

  9. Deactivation of Oxidation Catalysts

    Science.gov (United States)

    1991-05-01

    Levenspiel (Reference 10) have proposed an equivalent general expression of the form dS _KST (4) dtk to account for deactivation due to catalyst pore...Voorhies, A., IEC, 1954, vol. 37, p. 318. 10. Szepe, S., and 0. Levenspiel , Proc. 4th Europ. Symp. Chem. React. Eng., Pergamon Press, p. 265. 11. U.S

  10. Catalysts for Environmental Remediation

    DEFF Research Database (Denmark)

    Abrams, B. L.; Vesborg, Peter Christian Kjærgaard

    2013-01-01

    The properties of catalysts used in environmental remediation are described here through specific examples in heterogeneous catalysis and photocatalysis. In the area of heterogeneous catalysis, selective catalytic reduction (SCR) of NOx was used as an example reaction with vanadia and tungsta...

  11. Biocatalytic desulfurization (BDS) of petrodiesel fuels.

    Science.gov (United States)

    Mohebali, Ghasemali; Ball, Andrew S

    2008-08-01

    Oil refineries are facing many challenges, including heavier crude oils, increased fuel quality standards, and a need to reduce air pollution emissions. Global society is stepping on the road to zero-sulfur fuel, with only differences in the starting point of sulfur level and rate reduction of sulfur content between different countries. Hydrodesulfurization (HDS) is the most common technology used by refineries to remove sulfur from intermediate streams. However, HDS has several disadvantages, in that it is energy intensive, costly to install and to operate, and does not work well on refractory organosulfur compounds. Recent research has therefore focused on improving HDS catalysts and processes and also on the development of alternative technologies. Among the new technologies one possible approach is biocatalytic desulfurization (BDS). The advantage of BDS is that it can be operated in conditions that require less energy and hydrogen. BDS operates at ambient temperature and pressure with high selectivity, resulting in decreased energy costs, low emission, and no generation of undesirable side products. Over the last two decades several research groups have attempted to isolate bacteria capable of efficient desulfurization of oil fractions. This review examines the developments in our knowledge of the application of bacteria in BDS processes, assesses the technical viability of this technology and examines its future challenges.

  12. First-principles study of low Miller index Ni3S2 surfaces in hydrotreating conditions.

    Science.gov (United States)

    Aray, Yosslen; Vega, David; Rodriguez, Jesus; Vidal, Alba B; Grillo, Maria Elena; Coll, Santiago

    2009-03-12

    Density functional theory (DFT) calculations combined with surface thermodynamic arguments and the Gibbs-Curie-Wulff equilibrium morphology formalism have been employed to explore the effect of the reaction conditions, temperature (T), and gas-phase partial pressures (PH2 and PH2S) on the stability of nickel sulfide (Ni3S2) surfaces. Furthermore, the strength and nature of chemical bonds for selected Ni3S2 surface cuts were investigated with the quantum theory of atoms in molecules methodology. A particular analysis of the electrostatic potential within this theoretical framework is performed to study the potential activity of nickel sulfide nanoparticles as hydrodesulfurization (HDS) catalysts. The calculated thermodynamic surface stabilities and the resulting equilibrium morphology model suggest that unsupported Ni3S2 nanoparticles mainly expose (111) and (111) type surface faces in HDS conditions. Analysis of the electrostatic potential mapped onto a selected electron density isocontour (0.001 au) on those expose surface reveals a poor potential reactivity toward electron-donating reagents (i.e., low Lewis acidity). Consequently, a very low attraction between coordinatively unsaturated active sites (Lewis sites) exposed at the catalytic particles and the S atoms coming from reagent polluting molecules does inactive these kinds of particles for HDS.

  13. 非加氢脱硫技术研究进展及其在原油预脱硫中的应用展望%Progress of non-hydrodesulfurization technologies of producing clean fuels and pre-desulfurization of crude oil

    Institute of Scientific and Technical Information of China (English)

    郑凯元; 曲凤娇; 陈英杰; 刘东; 李雯; 邹京伦; 侯绪连

    2013-01-01

    综述了目前轻质油品非加氢脱硫以及原油预脱硫的相关技术,关于轻质油品非加氢脱硫技术详细叙述了氧化脱硫、吸附脱硫和溶剂萃取脱硫等技术的研究进展,简要介绍了络合脱硫、膜分离脱硫等技术,阐述了各非加氢脱硫技术的特点及脱硫效果;针对原油预脱硫技术,主要介绍了物理法原油预脱硫、超声-氧化法原油预脱硫、电化学法原油预脱硫以及微生物法原油预脱硫等技术的研究进展,指出应用能耗低、操作条件温和、脱硫效果好的非加氢脱硫手段是未来的发展趋势,同时指出综合应用非加氢脱硫技术对原油进行预脱硫处理将是未来重要的研究方向。%Research progress of several non-hydrodesulfurization technologies and processes of crude oil pre-desulfurization were reviewed. For light distillates,the non-hydrodesulfurization technologies including oxidative desulfurization,adsorptive desulfurization,solvent extraction desulfurization, extraction desulfurization and membrane separation desulfurization were introduced , and the characteristics and desulfurization effects of these non-hydrodesulfurization technologies were summarized. For crude oil,the desulfurization technologies of physical method,ultrasonic-oxidation method , electrochemical method and microorganism method were introduced. The non-hydrodesulfurization technologies with low energy consumption and mild operating conditions would be the trend of deep desulfurization,and comprehensive utilization of non-hydrodesulfurization technologies for crude oil pre-desulfurization would be an important research orientation.

  14. 噻吩在Au13和Pt13团簇上加氢脱硫的反应机理比较%Comparison of reaction mechanism of thiophene hydrodesulfurization on Au13 and Pt13 clusters

    Institute of Scientific and Technical Information of China (English)

    蒋军辉; 曹勇勇; 倪哲明; 张连阳

    2016-01-01

    采用密度泛函理论研究了噻吩在立方正八面体的M13( M=Au、Pt)团簇上的吸附和加氢脱硫行为。结果表明,噻吩以环吸附于Au13上的Hol-tri位或Pt13上的Hol-quadr位时最稳定,且Pt13上的吸附稳定性更高。在M13催化体系中,按间接加氢脱硫机理,反应可能依顺式加氢的方式进行;其中,C-S键断裂开环所需的活化能最高,是反应的限速步骤;按直接加氢脱硫机理,HS加氢所需活化能最高,是反应的限速步骤。同时该机理总体所需活化能较间接加氢脱硫机理更低,是更为合理的脱硫机理。噻吩加氢脱硫过程中,Au13体系为放热反应,而Pt13体系为吸热反应,并且Au13体系加氢所需活化能更低;因此,Au13更有利于噻吩加氢脱硫反应的进行。%The behaviors of thiophene adsorption and hydrodesulfurization on cubic octahedral M13 ( M = Au, Pt) clusters were investigated by density functional theory. The results show that the adsorption energy of thiophene on Pt13 is higher than that on Au13;on the Au13 cluster, the Hol-tri site is most stable for the thiophene adsorption with ring, whereas on the Pt13 cluster, the Hol-quadr site is most stable. By the indirect desulfurization mechanism, the desulfurization is achieved probably via the cis-hydrogenation; the removal of C-S is the rate-determining step. By the direct desulfurization mechanism, the HS hydrogenation turns to be the rate-determining step. The desulfurization is most likely via the direct desulfurization mechanism, which exhibits much lower activation energy than the indirect desulfurization mechanism. The energy change for thiophene desulfurization on the Au13 cluster is exothermic, whereas on the Pt13 cluster it is endothermic; as a result, the hydrodesulfurization on Au13 is much easier than that on Pt13 .

  15. 负载型纳米TiO2复合载体催化剂及其HDS活性研究%STUDY ON THE COMBINED SUPPORT CATALYSTS OF NANOSIZED TiO2 AND THEIR HDS ACTIVITIES

    Institute of Scientific and Technical Information of China (English)

    胡见波; 李传; 张明慧; 关乃佳; 陶克毅

    2002-01-01

    采用溶胶-凝胶法在γ-Al2O3上制备出负载型纳米TiO2,负载活性组分Co和Mo,对其进行了噻吩HDS活性评价,并与国产工业HDS催化剂T205进行比较,并提出负载型纳米TiO2为半球模型.

  16. Fluorination process using catalysts

    Science.gov (United States)

    Hochel, R.C.; Saturday, K.A.

    1983-08-25

    A process is given for converting an actinide compound selected from the group consisting of uranium oxides, plutonium oxides, uranium tetrafluorides, plutonium tetrafluorides and mixtures of said oxides and tetrafluorides, to the corresponding volatile actinide hexafluoride by fluorination with a stoichiometric excess of fluorine gas. The improvement involves conducting the fluorination of the plutonium compounds in the presence of a fluoride catalyst selected from the group consisting of CoF/sub 3/, AgF/sub 2/ and NiF/sub 2/, whereby the fluorination is significantly enhanced. The improvement also involves conducting the fluorination of one of the uranium compounds in the presence of a fluoride catalyst selected from the group consisting of CoF/sub 3/ and AgF/sub 2/, whereby the fluorination is significantly enhanced.

  17. Fluorination process using catalyst

    Science.gov (United States)

    Hochel, Robert C.; Saturday, Kathy A.

    1985-01-01

    A process for converting an actinide compound selected from the group consisting of uranium oxides, plutonium oxides, uranium tetrafluorides, plutonium tetrafluorides and mixtures of said oxides and tetrafluorides, to the corresponding volatile actinide hexafluoride by fluorination with a stoichiometric excess of fluorine gas. The improvement involves conducting the fluorination of the plutonium compounds in the presence of a fluoride catalyst selected from the group consisting of CoF.sub.3, AgF.sub.2 and NiF.sub.2, whereby the fluorination is significantly enhanced. The improvement also involves conducting the fluorination of one of the uranium compounds in the presence of a fluoride catalyst selected from the group consisting of CoF.sub.3 and AgF.sub.2, whereby the fluorination is significantly enhanced.

  18. Photo catalyst; Ko shokubai

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-07-01

    While titanium oxide is excited by the light, electrons of titanium oxide are taken away by the light energy to form positive holes. Water will be decomposed into hydrogen ion and hydroxy radical (OH) by these positive holes. This hydroxy radical is a strong reactive substance called active oxygen, it decomposes organisms. Besides this photo- catalyst function, the titanium oxide can also make surface of a substance superhydrophilic. The super hydrophilicity results in not forming water drops on the glass surface but spreading all over the surface to prevent a covering of fog on the glass surface. The published patents concerning the photo catalysts were 593 from Jan. 1998 to Jan. 1999. The applicant order is the first TOTO 143, the second Daikin Industry 19, the third Toshiba Raitech, Nitto Denko, Hitachi 17 respectively. (NEDO)

  19. High-Activity Dealloyed Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Kongkanand, Anusorn [General Motors LLC, Pontiac, MI (United States)

    2014-09-30

    Reduction of costly Pt usage in proton exchange membrane fuel cell electrodes is one of the major challenges towards development and commercialization of fuel cell vehicles. Although few have met the initial-kinetic activity requirements in a realistic fuel cell device, no catalyst material has ever met the demanding fuel cell durability targets set by DOE. In this project, a team of 4 universities and 2 companies came together to investigate a concept that appeared promising in preliminary non-fuel cell tests then to further develop the catalyst to a mature level ready for vehicle implementation. The team consists of academia with technical leadership in their respective areas, a catalyst supplier, and a fuel cell system integrator.The tightly collaborative project enabled development of a highly active and durable catalyst with performance that significantly exceeds that of previous catalysts and meets the DOE targets for the first time (Figure 1A). The catalyst was then further evaluated in full-active-area stack in a realistic vehicle operating condition (Figure 1B). This is the first public demonstration that one can realize the performance benefit and Pt cost reduction over a conventional pure Pt catalyst in a long-term realistic PEMFC system. Furthermore, systematic analyses of a range of catalysts with different performance after fuel cell testing allowed for correlation between catalyst microstructure and its electrocatalytic activity and durability. This will in turn aid future catalyst development.

  20. Olefin metathesis and catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Kukes, S. G.; Banks, R. L.

    1985-03-12

    Olefins are converted into other olefins having different numbers of carbon atoms by contact with a catalyst comprising an inorganic refractory material containing at least one of tungsten oxide and molybdenum oxide and a promoting amount of at least one treating agent selected from chlorinated silicon compounds, thionyl chloride, and sulfuryl chloride under conditions suitable for the treating agent to promote the activity of tungsten and molybdenum oxides for the disporoportionation reaction.

  1. 降低FCC汽油烯烃的措施%MEASURES FOR DECREASING OLEFINE OF FCC GASOLINE

    Institute of Scientific and Technical Information of China (English)

    郝代军

    2001-01-01

    The measures for decreasing olefin of FCC gasoline were introduced. Selecting FCC feed stock, improving FCCU process schemes, using FCC catalyst or co-catalyst which have function for decreasing FCC gasoline olefin are the effective measure to decrease olefin of FCC gasoline. Etherification of FCC light gasoline and hydrodesulfurization (HDS) of FCC heave gasoline , or hydrodesulfurization of FCC gasoline are also the effective measures for producing clean gasoline.%介绍了降低催化裂化(FCC)汽油烯烃的几项措施。从FCC技术自身来讲,优化原料结构、改善装置操作条件、选择降烯烃催化剂和使用降烯烃助剂等方法是简单易行的。如洛阳石油化工工程公司开发的LAP降低烯烃助剂可降低烯烃10个百分点,且辛烷值略有提高。另外,对FCC轻汽油进行醚化并对重汽油加氢脱硫,或者FCC汽油全馏分加氢脱硫降烯烃,也是降低FCC汽油烯烃的有效措施。

  2. Catalyst systems and uses thereof

    Science.gov (United States)

    Ozkan, Umit S.; Holmgreen, Erik M.; Yung, Matthew M.

    2012-07-24

    A method of carbon monoxide (CO) removal comprises providing an oxidation catalyst comprising cobalt supported on an inorganic oxide. The method further comprises feeding a gaseous stream comprising CO, and oxygen (O.sub.2) to the catalyst system, and removing CO from the gaseous stream by oxidizing the CO to carbon dioxide (CO.sub.2) in the presence of the oxidation catalyst at a temperature between about 20 to about 200.degree. C.

  3. Development of GREET Catalyst Module

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhichao [Argonne National Lab. (ANL), Argonne, IL (United States); Benavides, Pahola T. [Argonne National Lab. (ANL), Argonne, IL (United States); Dunn, Jennifer B. [Argonne National Lab. (ANL), Argonne, IL (United States); Cronauer, Donald C. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2015-09-01

    In this report, we develop energy and material flows for the production of five different catalysts (tar reforming, alcohol synthesis, Zeolite Socony Mobil-5 [ZSM-5], Mo/Co/ γ-Al2O3, and Pt/ γ-Al2O3) and two chemicals (olivine, dimethyl ether of polyethylene glycol [DEPG]). These compounds and catalysts are now included in the Greenhouse Gases, Regulated Emissions and Energy Use in Transportation (GREET™) catalyst module.

  4. Oxygen-reducing catalyst layer

    Energy Technology Data Exchange (ETDEWEB)

    O' Brien, Dennis P. (Maplewood, MN); Schmoeckel, Alison K. (Stillwater, MN); Vernstrom, George D. (Cottage Grove, MN); Atanasoski, Radoslav (Edina, MN); Wood, Thomas E. (Stillwater, MN); Yang, Ruizhi (Halifax, CA); Easton, E. Bradley (Halifax, CA); Dahn, Jeffrey R. (Hubley, CA); O' Neill, David G. (Lake Elmo, MN)

    2011-03-22

    An oxygen-reducing catalyst layer, and a method of making the oxygen-reducing catalyst layer, where the oxygen-reducing catalyst layer includes a catalytic material film disposed on a substrate with the use of physical vapor deposition and thermal treatment. The catalytic material film includes a transition metal that is substantially free of platinum. At least one of the physical vapor deposition and the thermal treatment is performed in a processing environment comprising a nitrogen-containing gas.

  5. Privileged chiral ligands and catalysts

    CERN Document Server

    Zhou, Qi-Lin

    2011-01-01

    This ultimate ""must have"" and long awaited reference for every chemist working in the field of asymmetric catalysis starts with the core structure of the catalysts, explaining why a certain ligand or catalyst is so successful. It describes in detail the history, the basic structural characteristics, and the applications of these ""privileged catalysts"". A novel concept that gives readers a much deeper insight into the topic.

  6. REACTOR FILLED WITH CATALYST MATERIAL, AND CATALYST THEREFOR

    NARCIS (Netherlands)

    Sie, S.T.

    1995-01-01

    Abstract of WO 9521691 (A1) Described is a reactor (1) at least partially filled with catalyst granules (11), which is intended for catalytically reacting at least one gas and at least one liquid with each other. According to the invention the catalyst granules (11) are collected in agglomerates

  7. Mechanochemistry, catalysis, and catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Butyagin, P.Yu.

    1987-07-01

    The physical basis of mechanochemistry and the reasons for the initiation and acceleration of chemical reactions upon the mechanical treatment of solids have been considered. The phenomenon of mechanical catalysis has been described in the example case of the oxidation of CO on oxide surfaces, and the nature of the active sites and the laws governing the mechanically activated chemisorption of gases on cleavage and friction surfaces of solids have been examined. The possibilities of the use of the methods of mechanochemistry in processes used to prepare catalysts have been analyzed in examples of decomposition reactions of inorganic compounds and solid-phase synthesis.

  8. In-situ characterization of heterogeneous catalysts

    CERN Document Server

    Rodriguez, Jose A; Chupas, Peter J

    2013-01-01

    Helps researchers develop new catalysts for sustainable fuel and chemical production Reviewing the latest developments in the field, this book explores the in-situ characterization of heterogeneous catalysts, enabling readers to take full advantage of the sophisticated techniques used to study heterogeneous catalysts and reaction mechanisms. In using these techniques, readers can learn to improve the selectivity and the performance of catalysts and how to prepare catalysts as efficiently as possible, with minimum waste. In-situ Characterization of Heterogeneous Catalysts feat

  9. Catalyst design for biorefining.

    Science.gov (United States)

    Wilson, Karen; Lee, Adam F

    2016-02-28

    The quest for sustainable resources to meet the demands of a rapidly rising global population while mitigating the risks of rising CO2 emissions and associated climate change, represents a grand challenge for humanity. Biomass offers the most readily implemented and low-cost solution for sustainable transportation fuels, and the only non-petroleum route to organic molecules for the manufacture of bulk, fine and speciality chemicals and polymers. To be considered truly sustainable, biomass must be derived from resources which do not compete with agricultural land use for food production, or compromise the environment (e.g. via deforestation). Potential feedstocks include waste lignocellulosic or oil-based materials derived from plant or aquatic sources, with the so-called biorefinery concept offering the co-production of biofuels, platform chemicals and energy; analogous to today's petroleum refineries which deliver both high-volume/low-value (e.g. fuels and commodity chemicals) and low-volume/high-value (e.g. fine/speciality chemicals) products, thereby maximizing biomass valorization. This article addresses the challenges to catalytic biomass processing and highlights recent successes in the rational design of heterogeneous catalysts facilitated by advances in nanotechnology and the synthesis of templated porous materials, as well as the use of tailored catalyst surfaces to generate bifunctional solid acid/base materials or tune hydrophobicity.

  10. Latent catalyst; Senzaisei shokubai

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-03-01

    Epoxy resin, an important function material to support such main industries as electric and electronic devices, automobiles, civil engineering, and building construction, is demanded of development of single liquid type resin having excellent quick hardening performance and storage stability. This requirement comes from environmental problems with an intention of saving energies and reducing resin wastes. The Company, using freely its independent phase separation technology that controls molecular structure of catalysts, developed a latent catalyst having excellent storage stability and high-temperature quick hardening performance. Its major features may be summarized as follows: (1) excellent storage stability at room temperature keeping the product stable for 2.5 months or longer (2 days in conventional products); (2) quick hardening performance hardening the resin in seven seconds at 150 degrees C (equivalent to conventional products); and (3) excellent insulation performance of hardened resin at 140 degrees C of 7 times 10 {sup 13} (ohm) (center dot) cm (2 times 10 {sup 12} (ohm) (center dot) cm in conventional products) (translated by NEDO)

  11. Transition states and modeling for Co9S8/MoS 2 catalysis

    Science.gov (United States)

    Gonzalez, Gabriel Angel

    Transition state computational studies of the sulfur removal from dibenzothiophene (DBT) molecule have herein been performed considering the Co9S8/MoS2 interface existing on unsupported Co/MoS2 catalysts. The linear synchronous transit (LST) and quadratic synchronous transit (QST) methods integrated in a density functional theory (DFT) program such as Dmol3 were used for the calculations of energy barriers of the transition states. Three different configurations present on the Co9S8/MoS2 interface have been envisaged as possible catalytic sites: sulfur-sulfur (S, S) sites, and molybdenum-sulfur (Mo, S) and molybdenum-molybdenum (Mo, Mo) edge sites. This study revealed that the (Mo, Mo) edge site is the most catalytically active site for the hydrodesulfurization (HDS) reaction followed by the (Mo, S) edge site while the (S, S) site shows almost inertness for the HDS reaction. This information allows us to propose clues to design new catalysts based on bulk Co9S8/MoS2 phases with higher efficiency by increasing the proportion of (Mo, Mo) edge sites.

  12. Stereospecific olefin polymerization catalysts

    Science.gov (United States)

    Bercaw, John E.; Herzog, Timothy A.

    1998-01-01

    A metallocene catalyst system for the polymerization of .alpha.-olefins to yield stereospecific polymers including syndiotactic, and isotactic polymers. The catalyst system includes a metal and a ligand of the formula ##STR1## wherein: R.sup.1, R.sup.2, and R.sup.3 are independently selected from the group consisting of hydrogen, C.sub.1 to C.sub.10 alkyl, 5 to 7 membered cycloalkyl, which in turn may have from 1 to 3 C.sub.1 to C.sub.10 alkyls as a substituent, C.sub.6 to C.sub.15 aryl or arylalkyl in which two adjacent radicals may together stand for cyclic groups having 4 to 15 carbon atoms which in turn may be substituted, or Si(R.sup.8).sub.3 where R.sup.8 is selected from the group consisting of C.sub.1 to C.sub.10 alkyl, C.sub.6 to C.sub.15 aryl or C.sub.3 to C.sub.10 cycloalkyl; R.sup.4 and R.sup.6 are substituents both having van der Waals radii larger than the van der Waals radii of groups R.sup.1 and R.sup.3 ; R.sup.5 is a substituent having a van der Waals radius less than about the van der Waals radius of a methyl group; E.sup.1, E.sup.2 are independently selected from the group consisting of Si(R.sup.9).sub.2, Si(R.sup.9).sub.2 --Si(R.sup.9).sub.2, Ge(R.sup.9).sub.2, Sn(R.sup.9).sub.2, C(R.sup.9).sub.2, C(R.sup.9).sub.2 --C(R.sup.9).sub.2, where R.sup.9 is C.sub.1 to C.sub.10 alkyl, C.sub.6 to C.sub.15 aryl or C.sub.3 to C.sub.10 cycloalkyl; and the ligand may have C.sub.S or C.sub.1 -symmetry. Preferred metals are selected from the group consisting of group III, group IV, group V or lanthanide group elements. The catalysts are used to prepare stereoregular polymers including polypropylene from .alpha.-olefin monomers.

  13. Ceramic catalyst materials

    Energy Technology Data Exchange (ETDEWEB)

    Sault, A.G.; Gardner, T.J. [Sandia National Laboratories, Albuquerque, NM (United States); Hanprasopwattanna, A.; Reardon, J.; Datye, A.K. [Univ. of New Mexico, Albuquerque, NM (United States)

    1995-08-01

    Hydrous titanium oxide (HTO) ion-exchange materials show great potential as ceramic catalyst supports due to an inherently high ion-exchange capacity which allows facile loading of catalytically active transition metal ions, and an ability to be cast as thin films on virtually any substrate. By coating titania and HTO materials onto inexpensive, high surface area substrates such as silica and alumina, the economics of using these materials is greatly improved, particularly for the HTO materials, which are substantially more expensive in the bulk form than other oxide supports. In addition, the development of thin film forms of these materials allows the catalytic and mechanical properties of the final catalyst formulation to be separately engineered. In order to fully realize the potential of thin film forms of titania and HTO, improved methods for the deposition and characterization of titania and HTO films on high surface area substrates are being developed. By varying deposition procedures, titania film thickness and substrate coverage can be varied from the submonolayer range to multilayer thicknesses on both silica and alumina. HTO films can also be formed, but the quality and reproducibility of these films is not nearly as good as for pure titania films. The films are characterized using a combination of isopropanol dehydration rate measurements, point of zero charge (PZC) measurements, BET surface area, transmission electron microscopy (TEM), and elemental analysis. In order to assess the effects of changes in film morphology on catalytic activity, the films are being loaded with MoO{sub 3} using either incipient wetness impregnation or ion-exchange of heptamolybdate anions followed by calcining. The MoO{sub 3} is then sulfided to form MOS{sub 2}, and tested for catalytic activity using pyrene hydrogenation and dibenzothiophene (DBT) desulfurization, model reactions that simulate reactions occurring during coal liquefaction.

  14. Development of GREET Catalyst Module

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhichao [Argonne National Lab. (ANL), Argonne, IL (United States). Energy Systems Division; Dunn, Jennifer B. [Argonne National Lab. (ANL), Argonne, IL (United States). Energy Systems Division; Cronauer, Donald C. [Argonne National Lab. (ANL), Argonne, IL (United States). Energy Systems Division

    2014-09-01

    Catalysts are critical inputs for many pathways that convert biomass into biofuels. Energy consumption and greenhouse gas (GHG) emissions during the production of catalysts and chemical inputs influence the life-cycle energy consumption, and GHG emissions of biofuels and need to be considered in biofuel life-cycle analysis (LCA). In this report, we develop energy and material flows for the production of three different catalysts (tar reforming, alcohol synthesis, Zeolite Socony Mobil-5 [ZSM-5]) and two chemicals (olivine, dimethyl ether of polyethylene glycol [DEPG]). These compounds and catalysts are now included in the Greenhouse Gases, Regulated Emissions and Energy Use in Transportation (GREET™) catalyst module. They were selected because they are consumed in existing U.S. Department of Energy (DOE) analyses of biofuel processes. For example, a thermochemical ethanol production pathway (indirect gasification and mixed alcohol synthesis) developed by the National Renewable Energy Laboratory (NREL) uses olivine, DEPG, and tar reforming and alcohol synthesis catalysts (Dutta et al., 2011). ZSM-5 can be used in biofuel production pathways such as catalytic upgrading of sugars into hydrocarbons (Biddy and Jones, 2013). Other uses for these compounds and catalysts are certainly possible. In this report, we document the data sources and methodology we used to develop material and energy flows for the catalysts and compounds in the GREET catalyst module. In Section 2 we focus on compounds used in the model Dutta et al. (2011) developed. In Section 3, we report material and energy flows associated with ZSM-5 production. Finally, in Section 4, we report results.

  15. Impeded solid state reactions and transformations in ceramic catalysts supports and catalysts

    Directory of Open Access Journals (Sweden)

    Ernő E. Kiss

    2012-12-01

    Full Text Available Impeded chemical reactions and impeded polymorphous transformation in materials are discussed, as desired effects, for stabilization of ceramic catalyst supports and ceramic based catalysts. This paper gives a short overview about the possibilities of slowing down the aging processes in ceramic catalyst supports and catalysts. Special attention is given to alumina and titania based catalysts.

  16. New hydrocracking catalysts increase throughput, run length

    Energy Technology Data Exchange (ETDEWEB)

    Huizinga, T. [Shell Internationale Petroleum Mij., The Hague (Netherlands); Theunissen, J.M.H. [Rayong Refinery Co. Ltd., Rayong (Thailand); Minderhoud, H.; Veen, R. van [Koninklijke/Shell-Lab., Amsterdam (Netherlands)

    1995-06-26

    An improved, second-stage hydrocracking catalyst has been developed by combining stabilized Y zeolites with amorphous silica alumina cracking components. A commercial application of this catalyst, along with a new, first-stage zeolitic hydrocracking catalyst, resulted in increased unit throughput and cycle length. The paper discusses the hydrocracking process, first-stage catalysts, second-stage catalysts, hydrogenation process, commercial results, and product properties.

  17. Biomass processing over gold catalysts

    CERN Document Server

    Simakova, Olga A; Murzin, Dmitry Yu

    2014-01-01

    The book describes the valorization of biomass-derived compounds over gold catalysts. Since biomass is a rich renewable feedstock for diverse platform molecules, including those currently derived from petroleum, the interest in various transformation routes has become intense. Catalytic conversion of biomass is one of the main approaches to improving the economic viability of biorefineries.  In addition, Gold catalysts were found to have outstanding activity and selectivity in many key reactions. This book collects information about transformations of the most promising and important compounds derived from cellulose, hemicelluloses, and woody biomass extractives. Since gold catalysts possess high stability under oxidative conditions, selective oxidation reactions were discussed more thoroughly than other critical reactions such as partial hydrogenation, acetalization, and isomerization. The influence of reaction conditions, the role of the catalyst, and the advantages and disadvantages of using gold are pre...

  18. The innovation catalysts.

    Science.gov (United States)

    Martin, Roger L

    2011-06-01

    A few years ago the software development company Intuit realized that it needed a new approach to galvanizing customers. The company's Net Promoter Score was faltering, and customer recommendations of new products were especially disappointing. Intuit decided to hold a two-day, off-site meeting for the company's top 300 managers with a focus on the role of design in innovation. One of the days was dedicated to a program called Design for Delight. The centerpiece of the day was a PowerPoint presentation by Intuit founder Scott Cook, who realized midway through that he was no Steve Jobs: The managers listened dutifully, but there was little energy in the room. By contrast, a subsequent exercise in which the participants worked through a design challenge by creating prototypes, getting feedback, iterating, and refining, had them mesmerized. The eventual result was the creation of a team of nine design-thinking coaches--"innovation catalysts"--from across Intuit who were made available to help any work group create prototypes, run experiments, and learn from customers. The process includes a "painstorm" (to determine the customer's greatest pain point), a "soljam" (to generate and then winnow possible solutions), and a "code-jam" (to write code "good enough" to take to customers within two weeks). Design for Delight has enabled employees throughout Intuit to move from satisfying customers to delighting them.

  19. Hydrocarbon conversion catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Hoek, A.; Huizinga, T.; Maxwell, I.E.

    1989-08-15

    This patent describes a process for hydrocracking hydrocarbon oils into products of lower average molecular weight and lower average boiling point. It comprises contacting a hydrocarbon oil at a temperature between 250{sup 0}C and 500{sup 0}C and a pressure up to 300 bar in the presence of hydrogen with a catalyst consisting essentially of a Y zeolite modified to have a unit cell size below 24.35A, a water absorption capacity (at 25{sup 0}C and a rho/rho/sub o/ value of 0.2) of at least 8% by weight of the zeolite and a pore volume of at least 0.25 ml/g wherein between 10% and 60% of the total pore volume is made up of pores having a diameter of at least 8 nm; an alumina binder and at least one hydrogenation component selected from the group consisting of a Group VI metal, a Group VIII metal and mixtures thereof.

  20. Probing topological electronic effects in catalysis: thiophene adsorption on NiMoS and CoMoS clusters

    Energy Technology Data Exchange (ETDEWEB)

    Borges Junior, Itamar; Silva, Alexander M., E-mail: itamar@ime.eb.br [Instituto Militar de Engenharia (IME), Rio de Janeiro-RJ (Brazil). Programa de Pos-Graduacao em Engenharia de Defesa

    2012-10-15

    A general two-step theoretical approach to study electronic redistributions in catalytic processes is presented. In the first step, density functional theory (DFT) is used to fully optimize two geometries: the cluster representing the catalyst and the cluster plus adsorbed molecule system. In the second step, the converged electron density is divided into multipoles centered on atomic sites according to a distributed multipole analysis which provides detailed topological information on the charge redistribution of catalyst and molecule before and after adsorption. This approach is applied to thiophene adsorption on the 10{sup -}10 metal edge of Ni(Co)MoS catalysts and compared to the same reaction on bare MoS{sub 2}. Calculated adsorption energies, geometries and multipole analysis indicate weak thiophene chemisorption on both cases. A Coulombic bond model showed that surface metal-sulfur bond strengths in Ni(Co)MoS promoted catalysts are considerably smaller than in bare MoS{sub 2}, thus confirming the origin of the enhancement of hydrodesulfurization (HDS) activity in these catalysts. (author)

  1. The role of reaction pathways and support interactions in the development of high activity hydrotreating catalysts

    DEFF Research Database (Denmark)

    Topsøe, Henrik; Hinnemann, Berit; Nørskov, Jens Kehlet

    2005-01-01

    Scanning tunneling microscopy (STM) investigations have recently provided the first atom-resolved images of reaction intermediates in the key steps of the hydrogenation (HYD) and direct desulfurization (DDS) pathways in hydrodesulfurization over MoS(2) nanoclusters. Surprisingly, special brim sites...

  2. Catalyst containing oxygen transport membrane

    Science.gov (United States)

    Christie, Gervase Maxwell; Wilson, Jamie Robyn; van Hassel, Bart Antonie

    2012-12-04

    A composite oxygen transport membrane having a dense layer, a porous support layer and an intermediate porous layer located between the dense layer and the porous support layer. Both the dense layer and the intermediate porous layer are formed from an ionic conductive material to conduct oxygen ions and an electrically conductive material to conduct electrons. The porous support layer has a high permeability, high porosity, and a high average pore diameter and the intermediate porous layer has a lower permeability and lower pore diameter than the porous support layer. Catalyst particles selected to promote oxidation of a combustible substance are located in the intermediate porous layer and in the porous support adjacent to the intermediate porous layer. The catalyst particles can be formed by wicking a solution of catalyst precursors through the porous support toward the intermediate porous layer.

  3. Catalyst containing oxygen transport membrane

    Energy Technology Data Exchange (ETDEWEB)

    Lane, Jonathan A.; Wilson, Jamie R.; Christie, Gervase Maxwell; Petigny, Nathalie; Sarantopoulos, Christos

    2017-02-07

    A composite oxygen transport membrane having a dense layer, a porous support layer and an intermediate porous layer located between the dense layer and the porous support layer. Both the dense layer and the intermediate porous layer are formed from an ionic conductive material to conduct oxygen ions and an electrically conductive material to conduct electrons. The porous support layer has a high permeability, high porosity, and a microstructure exhibiting substantially uniform pore size distribution as a result of using PMMA pore forming materials or a bi-modal particle size distribution of the porous support layer materials. Catalyst particles selected to promote oxidation of a combustible substance are located in the intermediate porous layer and in the porous support adjacent to the intermediate porous layer. The catalyst particles can be formed by wicking a solution of catalyst precursors through the porous support toward the intermediate porous layer.

  4. deNOx catalysts for biomass combustion

    DEFF Research Database (Denmark)

    Kristensen, Steffen Buus

    industrial reference catalyst, after impregnation of 225 mole potassium/g of catalyst. A catalyst plate was synthesised using 20 wt.% sepiolite mixed with nano catalyst, supported by a SiO2-fibre mesh. Realistic potassium poisoning was performed on the catalyst plate, by exposure in a potassium aerosol...... for 632 hours at 350 C. Owing to physical blocking of potassium by sepiolite fibres the composite catalyst showed a further increase in potassium resistance compared with the unsupported catalyst. Finally a refined mechanism was proposed for the nano particle SCR catalyst explaining insitu FTIR...... observation done on the system. Most importantly it indicated that the V=O bond did not break during the SCR reaction, suggesting that another oxygen is responsible for the activity of the active vanadia site....

  5. Novel Fischer-Tropsch catalysts. [DOE patent

    Science.gov (United States)

    Vollhardt, K.P.C.; Perkins, P.

    Novel compounds are described which are used as improved Fischer-Tropsch catalysts particularly for the conversion of CO + H/sub 2/ to gaseous and liquid hydrocarbons at milder conditions than with prior catalysts.

  6. Rhenium Nanochemistry for Catalyst Preparation

    Directory of Open Access Journals (Sweden)

    Vadim G. Kessler

    2012-08-01

    Full Text Available The review presents synthetic approaches to modern rhenium-based catalysts. Creation of an active center is considered as a process of obtaining a nanoparticle or a molecule, immobilized within a matrix of the substrate. Selective chemical routes to preparation of particles of rhenium alloys, rhenium oxides and the molecules of alkyltrioxorhenium, and their insertion into porous structure of zeolites, ordered mesoporous MCM matrices, anodic mesoporous alumina, and porous transition metal oxides are considered. Structure-property relationships are traced for these catalysts in relation to such processes as alkylation and isomerization, olefin metathesis, selective oxidation of olefins, methanol to formaldehyde conversion, etc.

  7. Quick Guide to Flash Catalyst

    CERN Document Server

    Elmansy, Rafiq

    2011-01-01

    How do you transform user interface designs created in Photoshop or Illustrator into interactive web pages? It's easier than you think. This guide shows you how to use Adobe Flash Catalyst to create interactive UIs and website wireframes for Rich Internet Applications-without writing a single line of code. Ideal for web designers, this book introduces Flash Catalyst basics with detailed step-by-step instructions and screenshots that illustrate every part of the process. You'll learn hands-on how to turn your static design or artwork into working user interfaces that can be implemented in Fla

  8. Modeling of a three-phase reactor for bitumen-derived gas oil hydrotreating

    Energy Technology Data Exchange (ETDEWEB)

    Chacon, R.; Canale, A.; Bouza, A. [Departamento de Termodinamica y Fenomenos de Transporte. Universidad Simon Bolivar, Caracas (Venezuela, Bolivarian Republic of); Sanchez, Y. [Departamento de Procesos y Sistemas. Universidad Simon Bolivar (Venezuela, Bolivarian Republic of)

    2012-01-15

    A three-phase reactor model for describing the hydrotreating reactions of bitumen-derived gas oil was developed. The model incorporates the mass-transfer resistance at the gas-liquid and liquid-solid interfaces and a kinetic rate expression based on a Langmuir-Hinshelwood-type model. We derived three correlations for determining the solubility of hydrogen (H{sub 2}), hydrogen sulfide (H{sub 2}S) and ammonia (NH{sub 3}) in hydrocarbon mixtures and the calculation of the catalyst effectiveness factor was included. Experimental data taken from the literature were used to determine the kinetic parameters (stoichiometric coefficients, reaction orders, reaction rate and adsorption constants for hydrodesulfuration (HDS) and hydrodenitrogenation (HDN)) and to validate the model under various operating conditions. Finally, we studied the effect of operating conditions such as pressure, temperature, LHSV, H{sub 2}/feed ratio and the inhibiting effect of H{sub 2}S on HDS and NH{sub 3} on HDN. (author)

  9. The Effects of Support and Promoter on Thiophene Hydrodesulfurization and Tetralin Hydrogenation%噻吩加氢脱硫和四氢萘催化加氢反应中载体和助剂的影响

    Institute of Scientific and Technical Information of China (English)

    季亚英; P.Afamasoev; 等

    2003-01-01

    为了更好地认识加氢脱硫和催化加氢反应中的载体影响和助剂效应,在同样的催化剂制备方法及反应条件下,研究了噻吩加氢脱硫(HDS)和四氢萘催化加氢(HYD)反应. 结果表明,对于无助剂的Mo和W催化剂,载体对催化活性的影响顺序为TiO2-Al2O3>ZrO2>Al2O3. 助剂的添加改变了催化剂活性顺序. Ni助剂催化剂的活性明显高于Co助剂催化剂. ZrO2担载的添加Ni的Mo和W催化剂分别获得了最佳的HDS和HYD活性. 然而,添加Pt的Mo和W催化剂其HDS和HYD活性仅是Pt与Mo(W)二者的加和,Pt与Mo(W)之间没有协同效应. 先将担载的Mo和W预硫化再将助剂引入体系的催化剂制备方法可以避免Ni和Co过早硫化形成类硫化镍(或硫化钴)物相,与采用螯合物分子方法制备的催化剂间有一定的相似性.

  10. Paraffin Alkylation Using Zeolite Catalysts in a slurry reactor: Chemical Engineering Principles to Extend Catalyst Lifetime

    NARCIS (Netherlands)

    Jong, K.P. de; Mesters, C.M.A.M.; Peferoen, D.G.R.; Brugge, P.T.M. van; Groot, C. de

    1996-01-01

    The alkylation of isobutane with 2-butene is carried out using a zeolitic catalyst in a well stirred slurry reactor. Whereas application of fixed bed technology using a solid acid alkylation catalyst has in the led to catalysts lifetimes in the range of minutes, in this work we report catalyst

  11. Efficient epoxidation of propene using molecular catalysts

    DEFF Research Database (Denmark)

    Markovits, Iulius I. E.; Anthofer, Michael H.; Kolding, Helene

    2014-01-01

    The epoxidation of propene is performed in homogeneous phase using various molecular catalysts and H2O2 or tert-butyl hydroperoxide as oxidants. A comparison between some molybdenum catalysts and methyltrioxorhenium (MTO) shows that the well known Re catalyst is the best among the examined...

  12. Catalysts and methods of using the same

    Energy Technology Data Exchange (ETDEWEB)

    Slowing, Igor Ivan; Kandel, Kapil

    2017-02-14

    The present invention provides a catalyst including a mesoporous silica nanoparticle and a catalytic material comprising iron. In various embodiments, the present invention provides methods of using and making the catalyst. In some examples, the catalyst can be used to hydrotreat fatty acids or to selectively remove fatty acids from feedstocks.

  13. Novel non-platinum metal catalyst material

    DEFF Research Database (Denmark)

    2014-01-01

    The present invention relates to a novel non-platinum metal catalyst material for use in low temperature fuel cells and electrolysers and to fuel cells and electrolysers comprising the novel non-platinum metal catalyst material. The present invention also relates to a novel method for synthesizing...... the novel non-platinum metal catalyst material....

  14. Preparation methods of mixed metal sulfide catalysts for deep hydrogenation of crude oils%原油深度加氢复合多金属硫化物催化剂的制备方法

    Institute of Scientific and Technical Information of China (English)

    蒋丽娟; 李来平; 张文钲

    2014-01-01

    复合多金属硫化物( MMS)催化剂主要用于原油的深度加氢,用于生产高十六烷值、低硫和低芳族化合物柴油。MMS催化剂包含NiMoS、NiWS、NiMoO、NiWO、NiMoWS和ZnMoWS催化剂等。综述MMS催化剂中二元复合金属硫化物催化剂和三元复合金属硫化物催化剂的制备方法,采用二步法即添加有机物作孔成形剂先制得催化剂前驱体,再由前驱体制得的MMS催化剂结构更松散,具有较大的比表面积(90 m2·g-1)和大孔容(大于0.3 cm3·g-1),因而具有更好的催化活性。对比不同MMS催化剂对重质柴油、焦油等的加氢裂解、加氢脱硫和加氢脱氮性能,认为NiMoW三元复合金属硫化物催化剂(50%Ni25%Mo25%W)的活性最优。%Mixed metal sulfide catalyst( MMS)catalysts are mainly used for deep hydroprocessing of refractory crudes to produce diesel oil with higher cetane number,lower sulfur and lower aromatic compounds. MMS catalysts include NiMoS,NiWS,NiMoO,NiWO,NiMoWS and ZnMoWS,etc. The preparation methods of MMS catalysts,including bi-metallic sulfide catalysts and tri-metallic sulfide catalysts,were summarized in this paper. The catalyst precursors were prepared by adding organic compounds as pore forming agents,and then the catalysts were prepared. The catalysts prepared by the two-steps method possessed dispersive structure. The attained catalyst with BET specific surface area of 90 m2·g-1 and pore volume of 0. 3 cm3 ·g-1 exhibited better catalytic activity. Compared with other several MMS catalysts,the hydrocracking,hydrodesulfurization and hydrodenitrification activities of NiMoW(50mol%Ni,25mol%Mo,25mol%W)tri-metallic sulfide catalysts for processing heavy diesel oil and tar were the best.

  15. Perovskite catalysts for oxidative coupling

    Science.gov (United States)

    Campbell, Kenneth D.

    1991-01-01

    Perovskites of the structure A.sub.2 B.sub.2 C.sub.3 O.sub.10 are useful as catalysts for the oxidative coupling of lower alkane to heavier hydrocarbons. A is alkali metal; B is lanthanide or lanthanum, cerium, neodymium, samarium, praseodymium, gadolinium or dysprosium; and C is titanium.

  16. Biodiesel production using heterogenous catalyst

    Science.gov (United States)

    The current transesterification of triacylglycerides (TAG) to produce biodiesel is based on the homogenous catalyst method using strong base such as hydroxides or methoxides. However, this method results in a number of problems: (1) acid pre-treatment is required of feedstocks high in free fatty ac...

  17. MECHANICAL STRENGTH AND RELIABILITY OF SOLID CATALYSTS

    Institute of Scientific and Technical Information of China (English)

    Yongdan Li; Dongfang Wu; Y.S. Lin

    2004-01-01

    The mechanical strength of solid catalysts is one of the key parameters for reliable and efficient performance of a fixed bed reactor. Some recent developments and their basic mechanics within this context are reviewed. The main concepts discussed are brittle fracture which leads to the mechanical failure of the catalyst pellets, measurement and statistical properties of the catalyst strength data, and mechanical reliability of the catalyst pellets and their packed bed. The scientific basis for the issues on the catalyst mechanical properties calls yet for further elucidation and advancement.

  18. Automotive Catalyst State Diagnosis Using Microwaves

    Directory of Open Access Journals (Sweden)

    Moos Ralf

    2015-01-01

    Full Text Available The state of catalysts plays a key role in automotive exhaust gas aftertreatment. The soot or ash loading of Diesel particulate filters, the oxygen loading degree in three-way catalysts, the amount of stored ammonia in SCR catalysts, or the NOx loading degree in NOx storage catalysts are important parameters that are today determined indirectly and in a model-based manner with gas sensors installed upstream and/or downstream of the catalysts. This contribution gives an overview on a novel approach to determine the catalyst state directly by a microwave-based technique. The method exploits the fact that the catalyst housing acts as a microwave cavity resonator. As “sensing” elements, one or two simple antennas are mounted inside the catalyst canning. The electrical properties of the catalyst device (ceramic honeycomb plus coating and storage material can be measured. Preferably, the resonance characteristics, e.g., the resonance frequencies, of selected cavity modes are observed. The information on the catalyst interior obtained in such a contactless manner is very well correlated with the catalyst state as will be demonstrated for different exhaust gas aftertreatment systems.

  19. Autothermal reforming catalyst having perovskite structure

    Science.gov (United States)

    Krumpel, Michael; Liu, Di-Jia

    2009-03-24

    The invention addressed two critical issues in fuel processing for fuel cell application, i.e. catalyst cost and operating stability. The existing state-of-the-art fuel reforming catalyst uses Rh and platinum supported over refractory oxide which add significant cost to the fuel cell system. Supported metals agglomerate under elevated temperature during reforming and decrease the catalyst activity. The catalyst is a perovskite oxide or a Ruddlesden-Popper type oxide containing rare-earth elements, catalytically active firs row transition metal elements, and stabilizing elements, such that the catalyst is a single phase in high temperature oxidizing conditions and maintains a primarily perovskite or Ruddlesden-Popper structure under high temperature reducing conditions. The catalyst can also contain alkaline earth dopants, which enhance the catalytic activity of the catalyst, but do not compromise the stability of the perovskite structure.

  20. Cationic ruthenium alkylidene catalysts bearing phosphine ligands.

    Science.gov (United States)

    Endo, Koji; Grubbs, Robert H

    2016-02-28

    The discovery of highly active catalysts and the success of ionic liquid immobilized systems have accelerated attention to a new class of cationic metathesis catalysts. We herein report the facile syntheses of cationic ruthenium catalysts bearing bulky phosphine ligands. Simple ligand exchange using silver(i) salts of non-coordinating or weakly coordinating anions provided either PPh3 or chelating Ph2P(CH2)nPPh2 (n = 2 or 3) ligated cationic catalysts. The structures of these newly reported catalysts feature unique geometries caused by ligation of the bulky phosphine ligands. Their activities and selectivities in standard metathesis reactions were also investigated. These cationic ruthenium alkylidene catalysts reported here showed moderate activity and very similar stereoselectivity when compared to the second generation ruthenium dichloride catalyst in ring-closing metathesis, cross metathesis, and ring-opening metathesis polymerization assays.

  1. Catalyst for Carbon Monoxide Oxidation

    Science.gov (United States)

    Davis, Patricia; Brown, Kenneth; VanNorman, John; Brown, David; Upchurch, Billy; Schryer, David; Miller, Irvin

    2010-01-01

    In many applications, it is highly desirable to operate a CO2 laser in a sealed condition, for in an open system the laser requires a continuous flow of laser gas to remove the dissociation products that occur in the discharge zone of the laser, in order to maintain a stable power output. This adds to the operating cost of the laser, and in airborne or space applications, it also adds to the weight penalty of the laser. In a sealed CO2 laser, a small amount of CO2 gas is decomposed in the electrical discharge zone into corresponding quantities of CO and O2. As the laser continues to operate, the concentration of CO2 decreases, while the concentrations of CO and O2 correspondingly increase. The increasing concentration of O2 reduces laser power, because O2 scavenges electrons in the electrical discharge, thereby causing arcing in the electric discharge and a loss of the energetic electrons required to boost CO2 molecules to lasing energy levels. As a result, laser power decreases rapidly. The primary object of this invention is to provide a catalyst that, by composition of matter alone, contains chemisorbed water within and upon its structure. Such bound moisture renders the catalyst highly active and very long-lived, such that only a small quantity of it needs to be used with a CO2 laser under ambient operating conditions. This object is achieved by a catalyst that consists essentially of about 1 to 40 percent by weight of one or more platinum group metals (Pt, Pd, Rh, Ir, Ru, Os, Pt being preferred); about 1 to 90 percent by weight of one or more oxides of reducible metals having multiple valence states (such as Sn, Ti, Mn, Cu, and Ce, with SnO2 being preferred); and about 1 to 90 percent by weight of a compound that can bind water to its structure (such as silica gel, calcium chloride, magnesium sulfate, hydrated alumina, and magnesium perchlorate, with silica gel being preferred). Especially beneficial results are obtained when platinum is present in the

  2. Biodiesel production using heterogeneous catalysts.

    Science.gov (United States)

    Semwal, Surbhi; Arora, Ajay K; Badoni, Rajendra P; Tuli, Deepak K

    2011-02-01

    The production and use of biodiesel has seen a quantum jump in the recent past due to benefits associated with its ability to mitigate greenhouse gas (GHG). There are large number of commercial plants producing biodiesel by transesterification of vegetable oils and fats based on base catalyzed (caustic) homogeneous transesterification of oils. However, homogeneous process needs steps of glycerol separation, washings, very stringent and extremely low limits of Na, K, glycerides and moisture limits in biodiesel. Heterogeneous catalyzed production of biodiesel has emerged as a preferred route as it is environmentally benign needs no water washing and product separation is much easier. The present report is review of the progress made in development of heterogeneous catalysts suitable for biodiesel production. This review shall help in selection of suitable catalysts and the optimum conditions for biodiesel production.

  3. Alternative alkali resistant deNOx catalysts

    DEFF Research Database (Denmark)

    Putluru, Siva Sankar Reddy; Kristensen, Steffen Buus; Due-Hansen, Johannes;

    2012-01-01

    Alternative alkali resistant deNOx catalysts were prepared using three different supports ZrO2, TiO2 and Mordenite zeolite. The majority of the catalysts were prepared by incipient wetness impregnation of a commercial support, with vanadium, copper or iron precursor, one catalyst was prepared...... by onepot sol–gel method. All catalysts were characterized by BET, XRPD and NH3-TPD. Initial SCR activities of 8 out of 9 catalysts showed higher NO conversion at least at one temperature in the temperature range 300–500 ◦C compared to the conventional V2O5-WO3/TiO2 catalyst. After potassium poisoning (100......–130 µmol of K/g of catalyst) the relative drop in SCR activity and acidity was lower for all the alternative catalysts compared to the industrial V2O5-WO3/TiO2 catalyst. Furthermore, Cu/MOR and Nano-V2O5/Sul-TiO2 catalysts showed 8–16 times higher SCR activities than the conventional even after high...

  4. Hydrocarbon conversion process and catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Hoek, A.; Huizinga, T.; Maxwell, I.E.

    1990-05-15

    This patent describes a catalyst composition. It comprises: a modified Y zeolite having a unit cell size below about 24.45 {angstrom}, a degree of crystallinity which is at least retained at increasing SiO{sub 2}/Al{sub 2}O{sub 3} molar ratios, a SiO{sub 2}/Al{sub 2}O{sub 3} molar ratio between about 8 to about 15, a water adsorption capacity at (25{degree}C and a p/p{sub {ital o}} value of 0.2) of between about 10--15% by weight of modified zeolite and a pore volume of at lest about 0.25 ml/g. Between about 10 to about 40% of the total pore volume is made up of pores having a diameter of at least about 8 nm; an amorphous cracking component comprising a silica-alumina containing 50--95% by weight of silica; a binder comprising alumina; from about 0.05 to about 10 percent by weight of nickel and from about 2 to about 40 percent by weight of tungsten, calculated as metals per 100 parts by weight of total catalyst. The modified Y zeolite and amorphous cracking component comprises about 60--85% by weight of the total catalyst, the binder comprises about 15--40% by weight of the total catalyst and the amount of modified Y zeolite ranges between about 10--75% of the combined amount of modified Y zeolite and amorphous cracking component.

  5. Catalysts from synthetic genetic polymers.

    Science.gov (United States)

    Taylor, Alexander I; Pinheiro, Vitor B; Smola, Matthew J; Morgunov, Alexey S; Peak-Chew, Sew; Cozens, Christopher; Weeks, Kevin M; Herdewijn, Piet; Holliger, Philipp

    2015-02-19

    The emergence of catalysis in early genetic polymers such as RNA is considered a key transition in the origin of life, pre-dating the appearance of protein enzymes. DNA also demonstrates the capacity to fold into three-dimensional structures and form catalysts in vitro. However, to what degree these natural biopolymers comprise functionally privileged chemical scaffolds for folding or the evolution of catalysis is not known. The ability of synthetic genetic polymers (XNAs) with alternative backbone chemistries not found in nature to fold into defined structures and bind ligands raises the possibility that these too might be capable of forming catalysts (XNAzymes). Here we report the discovery of such XNAzymes, elaborated in four different chemistries (arabino nucleic acids, ANA; 2'-fluoroarabino nucleic acids, FANA; hexitol nucleic acids, HNA; and cyclohexene nucleic acids, CeNA) directly from random XNA oligomer pools, exhibiting in trans RNA endonuclease and ligase activities. We also describe an XNA-XNA ligase metalloenzyme in the FANA framework, establishing catalysis in an entirely synthetic system and enabling the synthesis of FANA oligomers and an active RNA endonuclease FANAzyme from its constituent parts. These results extend catalysis beyond biopolymers and establish technologies for the discovery of catalysts in a wide range of polymer scaffolds not found in nature. Evolution of catalysis independent of any natural polymer has implications for the definition of chemical boundary conditions for the emergence of life on Earth and elsewhere in the Universe.

  6. Atomic-scale investigation of the interaction of organic molecules with MoS2-based hydrotreating model catalysts

    DEFF Research Database (Denmark)

    Salazar Moreira, Norberto José

    2017-01-01

    the presence of the reduced MoOx phase impedes the MoS2 growth and leads to rather stable amorphous oxysulfide phases. The sulfidation in H2S atmosphere of molybdenum metal and bimetallic cobalt-molybdenum clusters deposited on Au(111) facilitate instead the formation of well-dispersed MoS2 and Co-promoted Mo...... is reduced to 50%. The reduction of the nanoparticles in H2 reveals a variety of possible active sites which indicates that the catalysts are now present in their active states for HDS reactions.These active sites are shown to be reactive with some of the typical sulfur heterocyclic compounds present in real...... study of the adsorption sites for these sulfur and nitrogen-containing molecules is present in this thesis.In summary, the research in this PhD thesis elucidates some of the fundamental questions regarded to the understanding of the active structures, preferable adsorption sites and deactivation origin...

  7. Catalysts for decomposing ozone tail gas

    Institute of Scientific and Technical Information of China (English)

    LIU Chang-an; SUN De-zhi; WANG Hui; LI Wei

    2003-01-01

    The preparation of immobilizing-catalysts for decomposing ozone by using dipping method was studied. XRD, XPS and TEM were used to characterize the catalysts. The three kinds of catalysts were selected preferentially, and their catalytic activities were investigated. The results showed that the catalyst with activated carbon dipping acetate (active components are Mn: Cu = 3:2, active component proportion in catalyst is 15%, calcination temperature is 200℃ ) has the best catalytic activity for ozone decomposing. One gram of catalyst can decompose 17.6 g ozone at initial ozone concentration of 2.5 g/m3 and the residence time in reactor of 0.1 s. The experimental results also indicated that humidity of reaction system had negative effect on catalytic activity.

  8. Synthesis and characterization of mesoporous hydrocracking catalysts

    Science.gov (United States)

    Munir, D.; Usman, M. R.

    2016-08-01

    Mesoporous catalysts have shown great prospective for catalytic reactions due to their high surface area that aids better distribution of impregnated metal. They have been found to contain more adsorption sites and controlled pore diameter. Hydrocracking, in the presence of mesoporous catalyst is considered more efficient and higher conversion of larger molecules is observed as compared to the cracking reactions in smaller microporous cavities of traditional zeolites. In the present study, a number of silica-alumina based mesoporous catalysts are synthesized in the laboratory. The concentration and type of surfactants and quantities of silica and alumina sources are the variables studied in the preparation of catalyst supports. The supports prepared are well characterized using SEM, EDX, and N2-BET techniques. Finally, the catalysts are tested in a high pressure autoclave reactor to study the activity and selectivity of the catalysts for the hydrocracking of a model mixture of plastics comprising of LDPE, HDPE, PP, and PS.

  9. Organic synthesis with olefin metathesis catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Grubbs, R.H. [California Institute of Technology, Pasadena, CA (United States)

    1995-12-31

    Over the past nine years, early transition metal catalysts for the ring opening metathesis polymerization of cyclic olefins have been developed. These catalysts are simple organometallic complexes containing metal carbon multiple bonds that in most cases polymerize olefins by a living process. These catalysts have been used to prepare a family of near monodispersed and structurally homogeneous polymers. A series of group VII ROMP catalysts that allow a wide range of functionality to be incorporated into the polymer side chains have been prepared. The most important member of this family of complexes are the bisphosphinedihalo-ruthenium carbene complexes. These polymerization catalysts can also be used in the synthesis of fine chemicals by ring closing (RCM) and vinyl coupling reactions. The availability of the group VII catalysts allow metathesis to be carried out on highly functionalized substrates such as polypeptides and in unusual environments such as in aqueous emulsions.

  10. Methane Tri-reforming over nickel catalysts

    OpenAIRE

    García Vargas, José Manuel

    2014-01-01

    The present work is part of a research program carried out in the Department of Chemical Engineering at the University of Castilla-La Mancha, focused in the preparation, characterization and evaluation of catalysts that can be applied in industrially relevant reactions. In this way, the PhD work reported here was aimed to study and improve nickel catalysts applied to the tri-reforming process, evaluating the role of support, precursor and promoter and optimizing the catalyst preparation. Furt...

  11. Manufacture of Catalyst Systems for Ammonia Conversion

    Institute of Scientific and Technical Information of China (English)

    GAKH S.V.; SAVENKOV D.A.

    2012-01-01

    Platinum catalyst gauzes have been in use since the moment of development of the process of catalyst oxidation of ammonia for production of nitric acid or hydrocyanic acid.Catalyst gauzes are usually made of platinum or its alloys with rhodium and palladium.These precious metals have remarkable properties that make them ideal catalysts for acceleration of the ammonia/oxygen reaction.In 2008,OJSC "SIC ‘Supermetal’" and Umicore AG&Co.KG launched a production line for Pt-alloy-based catalyst systems to be used for ammonia oxidation in the production of weak nitric acid.Catalyst systems consist of a pack of catalyst gauzes and a pack of catchment gauzes,which are made using flat-bed knitting machines and wire-cloth looms.Today,up-to-date catalyst systems MKSpreciseTM are being manufactured,the basic advantages of which are an individual structure of gauzes and composition of the material,which allows to define precisely the position of each gauze in the catalyst pack,a high activity of the catalyst pack,direct catching of platinum and rhodium in the catalyst system,and a reasonable combination of single- and multilayer types of gauzes.This makes it possible to vary the configuration of the catalyst and select an optimum composition of the system to ensure the maximum efficiency of the ammonia oxidation process.We also produce the catchment systems that allow to find the best decision from the economic point view for each individual case.

  12. Oxidation catalysts on alkaline earth supports

    Science.gov (United States)

    Mohajeri, Nahid

    2017-03-21

    An oxidation catalyst includes a support including particles of an alkaline earth salt, and first particles including a palladium compound on the support. The oxidation catalyst can also include precious metal group (PMG) metal particles in addition to the first particles intermixed together on the support. A gas permeable polymer that provides a continuous phase can completely encapsulate the particles and the support. The oxidation catalyst may be used as a gas sensor, where the first particles are chemochromic particles.

  13. Oxidation catalysts on alkaline earth supports

    Energy Technology Data Exchange (ETDEWEB)

    Mohajeri, Nahid

    2017-03-21

    An oxidation catalyst includes a support including particles of an alkaline earth salt, and first particles including a palladium compound on the support. The oxidation catalyst can also include precious metal group (PMG) metal particles in addition to the first particles intermixed together on the support. A gas permeable polymer that provides a continuous phase can completely encapsulate the particles and the support. The oxidation catalyst may be used as a gas sensor, where the first particles are chemochromic particles.

  14. Molecular catalysts structure and functional design

    CERN Document Server

    Gade, Lutz H

    2014-01-01

    Highlighting the key aspects and latest advances in the rapidly developing field of molecular catalysis, this book covers new strategies to investigate reaction mechanisms, the enhancement of the catalysts' selectivity and efficiency, as well as the rational design of well-defined molecular catalysts. The interdisciplinary author team with an excellent reputation within the community discusses experimental and theoretical studies, along with examples of improved catalysts, and their application in organic synthesis, biocatalysis, and supported organometallic catalysis. As a result, readers wil

  15. POLYMER-SUPPORTED LEWIS ACID CATALYSTS. VI. POLYSTYRENE-BONDED STANNIC CHLORIDE CATALYST

    Institute of Scientific and Technical Information of China (English)

    RAN Ruicheng; FU Diankui

    1991-01-01

    A polystyrene-bonded stannic chloride catalyst was synthesized by the method of lithium polystyryl combined with stannic chloride. This catalyst is a polymeric organometallic compound containing 0.25 mmol Sn(IV)/g catalyst. The catalyst showed sufficient stability and catalytic activity in organic reaction such as esterification, acetalation and ketal formation, and it could be reused many times without losing its catalytic activity.

  16. Silica deactivation of bead VOC catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Libanati, C.; Pereira, C.J. [Research Division, W. R. Grace and Co., Columbia, MD (United States); Ullenius, D.A. [Grace TEC Systems, De Pere, WI (United States)

    1998-01-15

    Catalytic oxidation is a key technology for controlling the emissions of Volatile Organic Compounds (VOCs) from industrial plants. The present paper examines the deactivation by silica of bead VOC catalysts in a flexographic printing application. Post mortem analyses of field-aged catalysts suggest that organosilicon compounds contained in the printing ink diffuse into the catalyst and deposit as silica particles in the micropores. Laboratory activity evaluation of aged catalysts suggests that silica deposition is non-selective and that silica masks the noble metal active site

  17. Nanoparticular metal oxide/anatase catalysts

    DEFF Research Database (Denmark)

    2010-01-01

    The present invention concerns a method of preparation of nanoparticular metal oxide catalysts having a narrow particle size distribution. In particular, the invention concerns preparation of nanoparticular metal oxide catalyst precursors comprising combustible crystallization seeds upon which...... the catalyst metai oxide is co-precipitated with the carrier metal oxide, which crystallization seeds are removed by combustion in a final calcining step. The present invention also concerns processes wherein the nanoparticular metal oxide catalysts of the invention are used, such as SCR (deNOx) reactions...

  18. The development of aqueous transfer hydrogenation catalysts.

    Science.gov (United States)

    Robertson, Andrew; Matsumoto, Takahiro; Ogo, Seiji

    2011-10-28

    This review discusses the development of aqueous phase, homogeneous, transfer hydrogenation catalysis. Transfer hydrogenation catalysts, based on Ru, Ir and Rh, reduce organic substrates in water by assisting the transfer of hydrogen from simple donor species. These catalysts are expected to have significant benefits when compared with organic phase catalysts, including greater activity, greater selectivity and smaller environmental impact. They will therefore be expected to make a significant contribution to homogeneous catalysis and 'green chemistry'. Here, we comprehensively examine these catalysts, paying special attention to structural features.

  19. Nitrogen oxides storage catalysts containing cobalt

    Science.gov (United States)

    Lauterbach, Jochen; Snively, Christopher M.; Vijay, Rohit; Hendershot, Reed; Feist, Ben

    2010-10-12

    Nitrogen oxides (NO.sub.x) storage catalysts comprising cobalt and barium with a lean NO.sub.x storage ratio of 1.3 or greater. The NO.sub.x storage catalysts can be used to reduce NO.sub.x emissions from diesel or gas combustion engines by contacting the catalysts with the exhaust gas from the engines. The NO.sub.x storage catalysts can be one of the active components of a catalytic converter, which is used to treat exhaust gas from such engines.

  20. New Trends in Gold Catalysts

    Directory of Open Access Journals (Sweden)

    Leonarda F. Liotta

    2014-07-01

    Full Text Available Gold is an element that has fascinated mankind for millennia. The catalytic properties of gold have been a source of debate, due to its complete chemical inertness when in a bulk form, while it can oxidize CO at temperatures as low as ~200 K when in a nanocrystalline state, as discovered by Haruta in the late 1980s [1]. Since then, extensive activity in both applied and fundamental research on gold has been initiated. The importance of the catalysis by gold represents one of the fasted growing fields in science and is proven by the promising applications in several fields, such as green chemistry and environmental catalysis, in the synthesis of single-walled carbon nanotubes, as modifiers of Ni catalysts for methane steam and dry reforming reactions and in biological and electrochemistry applications. The range of reactions catalyzed by gold, as well as the suitability of different supports and the influence of the preparation conditions have been widely explored and optimized in applied research [2]. Gold catalysts appeared to be very different from the other noble metal-based catalysts, due to their marked dependence on the preparation method, which is crucial for the genesis of the catalytic activity. Several methods, including deposition-precipitation, chemical vapor deposition and cation adsorption, have been applied for the preparation of gold catalysts over reducible oxides, like TiO2. Among these methods, deposition-precipitation has been the most frequently employed method for Au loading, and it involves the use of tetrachloroauric (III acid as a precursor. On the other hand, the number of articles dealing with Au-loaded acidic supports is smaller than that on basic supports, possibly because the deposition of [AuCl4]− or [AuOHxCl4−x]− species on acidic supports is difficult, due to their very low point of zero charge. Despite this challenge, several groups have reported the use of acidic zeolites as supports for gold. Zeolites

  1. Off-gas catalyst. Abgaskatalysator

    Energy Technology Data Exchange (ETDEWEB)

    Saris, L.; Kloeck, H.

    1987-02-19

    The invention deals with a waste gas catalyst with a thermo-resistant SiO{sub 2} and Al{sub 2}O{sub 3} containing carrier of snarled ceramic fibres which form between themselves the flow paths for the waste gas to be purified and which are coated with platinum, palladium and/or rhodium. The ceramic fibres forming the carrier consist of SiO{sub 2} and Al{sub 2}O{sub 3} and have a diameter of 1 to 10 {mu}m. (orig./RB).

  2. Thermodynamic Properties of Supported Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Gorte, Raymond J.

    2014-03-26

    The goals of this work were to develop Coulometric Titration as a method for characterizing the thermodynamic redox properties of oxides and to apply this technique to the characterization of ceria- and vanadia-based catalysts. The redox properties of ceria and vanadia are a major part of what makes these materials catalytically active but their properties are also dependent on their structure and the presence of other oxides. Quantifying these properties through the measurement of oxidation energetics was the goal of this work.

  3. Process development for the separation and recovery of Mo and Co from chloride leach liquors of petroleum refining catalyst by solvent extraction

    Energy Technology Data Exchange (ETDEWEB)

    Banda, Raju [Department of Advanced Material Science and Engineering, Mokpo National University, Chonnam 534-729 (Korea, Republic of); Sohn, Seong Ho [Korea Institute of Industrial Technology, Incheon Technology Service Centre, 7-47, Songdo-dong, Incheon 406-840 (Korea, Republic of); Lee, Man Seung, E-mail: mslee@mokpo.ac.kr [Department of Advanced Material Science and Engineering, Mokpo National University, Chonnam 534-729 (Korea, Republic of)

    2012-04-30

    Highlights: Black-Right-Pointing-Pointer Separation of Mo and Co from HCl solution was investigated by solvent extraction. Black-Right-Pointing-Pointer The solution was synthetic leaching solution of spent HDS catalysts. Black-Right-Pointing-Pointer Extraction with TOPO led to complete separation of Mo. Black-Right-Pointing-Pointer Alamine 308 can separate Co from the Mo free raffinate. Black-Right-Pointing-Pointer Recovery percentage of both metals was higher than 99%. - Abstract: The separation and recovery of Mo and Co from the synthetic chloride leach liquors of petroleum refining catalyst has been investigated by employing TOPO and Alamine 308 as extractants. The synthetic leach liquor contained Mo 394 mg/L, Al 1782 mg/L, Co 119 mg/L in 3 M HCl. The separation of Mo from Co and Al was achieved with 0.05 M TOPO in Escaid 110 and complete stripping of Mo was attained with combination of 0.1 M NH{sub 4}OH and 0.05 M (NH{sub 4}){sub 2}CO{sub 3}. After separation of molybdenum, cobalt can be selectively extracted by Alamine 308 from Mo free raffinate after adjusting the concentration of chloride ion to 5 M by adding AlCl{sub 3}. The back-extraction of cobalt was obtained easily from loaded Alamine 308 with acidified water (pH = 1.0). McCabe-Thiele diagrams were constructed from the extraction and stripping experiments of each element (Mo and Co). From the batch simulation of the counter-current extraction and stripping experiments, it was confirmed that Mo and Co recovery of 99.4% and 99.1% respectively was obtained from the synthetic leach liquor of the chloride solutions. Finally a hydrometallurgical process flow sheet was developed.

  4. European workshop on spent catalysts. Book of abstracts

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-07-01

    In 1999 and 2002 two well attended workshops on recycling, regeneration, reuse and disposal of spent catalysts took place in Frankfurt. This series has been continued in Berlin. The workshop was organized in collaboration with DGMK, the German Society for Petroleum and Coal Science and Technology. Contributions were in the following areas of catalyst deactivation: recycling of spent catalysts in chemical and petrochemical industry, recycling of precious metal catalysts and heterogenous base metal catalysts, legal aspects of transboundary movements, catalyst regeneration, quality control, slurry catalysts, commercial reactivation of hydrotreating catalysts. (uke)

  5. Catalyst, Volume 9, Number 3, Winter 2008

    Science.gov (United States)

    Ryan, Barbara E., Ed.

    2008-01-01

    The U.S. Department of Education's Higher Education Center for Alcohol and Other Drug Abuse and Violence Prevention publishes "Catalyst," a newsletter covering current Alcohol and Other Drug Abuse and Violence (AODV) prevention issues at institutions of higher education. "Catalyst" discusses emerging issues and highlights innovative efforts on…

  6. Catalyst, Volume 10, Number 1, Spring 2008

    Science.gov (United States)

    Ryan, Barbara E., Ed.

    2008-01-01

    The U.S. Department of Education's Higher Education Center for Alcohol and Other Drug Abuse and Violence Prevention publishes "Catalyst," a newsletter covering current Alcohol and Other Drug Abuse and Violence (AODV) prevention issues at institutions of higher education. "Catalyst" discusses emerging issues and highlights innovative efforts on…

  7. NEW REFORMING CATALYST DEVELOPED BY RIPP

    Institute of Scientific and Technical Information of China (English)

    PUZhong-ying

    2003-01-01

    To meet the demands for high-octane gasoline and aromatics,catalytic reforming process has been advancing quickly in China.The reforming catalysts developed by RIPP have been used in more than 80% capacity of domestic CCR and SR units.This paper introduces the properties of PSVI CCR catalyst developed by RIPP in recent years and also the result from commercial units.The PS-VI catalyst has high activity and good selectivity,under the same reaction conditions,the carbon on catalyst was lowered by 26% in mass as compared with that of the reference catalyst.Among the SR reforming catalysts,the new type of PRT series catalysts have excellent performance at low reaction pressure compared with the ref.Cat A.The aromatics and reformate mass yields of PRT catalyst were 2%-3% and 3%,respectively ,higher than those of Cat A,and the run length was 30%-40% longer as well,which exhibits good prospect of application.

  8. Catalyst, Volume 10, Number 2, Fall 2008

    Science.gov (United States)

    Ryan, Barbara E., Ed.

    2008-01-01

    The U.S. Department of Education's Higher Education Center for Alcohol and Other Drug Abuse and Violence Prevention publishes "Catalyst," a newsletter covering current Alcohol and Other Drug Abuse and Violence (AODV) prevention issues at institutions of higher education. "Catalyst" discusses emerging issues and highlights innovative efforts on…

  9. Ligand iron catalysts for selective hydrogenation

    Science.gov (United States)

    Casey, Charles P.; Guan, Hairong

    2010-11-16

    Disclosed are iron ligand catalysts for selective hydrogenation of aldehydes, ketones and imines. A catalyst such as dicarbonyl iron hydride hydroxycyclopentadiene) complex uses the OH on the five member ring and hydrogen linked to the iron to facilitate hydrogenation reactions, particularly in the presence of hydrogen gas.

  10. Magnetically retrievable catalysts for organic synthesis

    Science.gov (United States)

    The use of magnetic nanoparticles (MNPs) as a catalyst in organic synthesis has become a subject of intense investigation. The recovery of expensive catalysts after catalytic reaction and reusing it without losing its activity is an important feature in the sustainable process de...

  11. Olefin polymerization over supported chromium oxide catalysts

    NARCIS (Netherlands)

    Weckhuysen, B.M.; Schoonheydt, R.A.

    1999-01-01

    Cr/SiO2 or Phillips-type catalysts are nowadays responsible for a large fraction of all polyethylene (HDPE and LLDPE) worldwide produced. In this review, several key-properties of Cr/SiO2 catalysts will be discussed in relation to their polymerization characteristics. It will be shown how the polyol

  12. Chemical engineering design of CO oxidation catalysts

    Science.gov (United States)

    Herz, Richard K.

    1987-01-01

    How a chemical reaction engineer would approach the challenge of designing a CO oxidation catalyst for pulsed CO2 lasers is described. CO oxidation catalysts have a long history of application, of course, so it is instructive to first consider the special requirements of the laser application and then to compare them to the characteristics of existing processes which utilize CO oxidation catalysts. All CO2 laser applications require a CO oxidation catalyst with the following characteristics: (1) active at stoichiometric ratios of O2 and CO, (2) no inhibition by CO2 or other components of the laser environment, (3) releases no particulates during vibration or thermal cycling, and (4) long lifetime with a stable activity. In all applications, low consumption of power is desirable, a characteristic especially critical in aerospace applications and, thus, catalyst activity at low temperatures is highly desirable. High power lasers with high pulse repetition rates inherently require circulation of the gas mixture and this forced circulation is available for moving gas past the catalyst. Low repetition rate lasers, however, do not inherently require gas circulation, so a catalyst that did not require such circulation would be favorable from the standpoint of minimum power consumption. Lasers designed for atmospheric penetration of their infrared radiation utilize CO2 formed from rare isotopes of oxygen and this application has the additional constraint that normal abundance oxygen isotopes in the catalyst must not exchange with rare isotopes in the gas mixture.

  13. Immobilized Ruthenium Catalyst for Carbon Dioxide Hydrogenation

    Institute of Scientific and Technical Information of China (English)

    Ying Min YU; Jin Hua FEI; Yi Ping ZHANG; Xiao Ming ZHENG

    2006-01-01

    Three kinds of cross linked polystyrene resin (PS) supported ruthenium complexes were developed as catalysts for the synthesis of formic acid from carbon dioxide hydrogenation. Many factors, such as the functionalized supports, solvents and ligands, could influence their activities and reuse performances greatly. These immobilized catalysts also offer the industrial advantages such as easy separation.

  14. Magnetically retrievable catalysts for organic synthesis

    Science.gov (United States)

    The use of magnetic nanoparticles (MNPs) as a catalyst in organic synthesis has become a subject of intense investigation. The recovery of expensive catalysts after catalytic reaction and reusing it without losing its activity is an important feature in the sustainable process de...

  15. Method for reactivating catalysts and a method for recycling supercritical fluids used to reactivate the catalysts

    Science.gov (United States)

    Ginosar, Daniel M.; Thompson, David N.; Anderson, Raymond P.

    2008-08-05

    A method of reactivating a catalyst, such as a solid catalyst or a liquid catalyst. The method comprises providing a catalyst that is at least partially deactivated by fouling agents. The catalyst is contacted with a fluid reactivating agent that is at or above a critical point of the fluid reactivating agent and is of sufficient density to dissolve impurities. The fluid reactivating agent reacts with at least one fouling agent, releasing the at least one fouling agent from the catalyst. The at least one fouling agent becomes dissolved in the fluid reactivating agent and is subsequently separated or removed from the fluid reactivating agent so that the fluid reactivating agent may be reused. A system for reactivating a catalyst is also disclosed.

  16. New catalysts for clean environment

    Energy Technology Data Exchange (ETDEWEB)

    Maijanen, A.; Hase, A. [eds.] [VTT Chemical Technology, Espoo (Finland)

    1996-12-31

    VTT launched a Research Programme on Chemical Reaction Mechanisms (CREAM) in 1993. The three-year programme (1993-1995) has focused on reaction mechanisms relevant to process industries and aimed at developing novel catalysts and biocatalysts for forest, food, and specialty chemicals industries as well as for energy production. The preliminary results of this programme have already been presented in the first symposium organized in Espoo in September 1994. To conclude the programme the second symposium is organized in Otaniemi, Espoo on January 29 - 30, 1996. Papers by 19 speakers and 17 poster presentations of the 1996 Symposium are included in this book. The Symposium consists of four sessions: Biotechnology for Natural Fibers Processing, New Biocatalysts, Catalysts for Clean Energy, and New Opportunities for Chemical Industry. The CREAM programme has tried to foresee solutions for the problems challenged by the public concern on environmental aspects, especially dealing with industrial processes and novel use of raw materials and energy. The programme has followed the basic routes that can lead to natural and simple solutions to develop processes in the fields of forest, food fine chemicals, and energy industry. This symposium presents the results of the programme to learn and further discuss together with the international experts that have been invited as keynote speakers. (author)

  17. Nanostructured Basic Catalysts: Opportunities for Renewable Fuels

    Energy Technology Data Exchange (ETDEWEB)

    Conner, William C; Huber, George; Auerbach, Scott

    2009-06-30

    This research studied and developed novel basic catalysts for production of renewable chemicals and fuels from biomass. We focused on the development of unique porous structural-base catalysts zeolites. These catalysts were compared to conventional solid base materials for aldol condensation, that were being commercialized for production of fuels from biomass and would be pivotal in future biomass conversion to fuels and chemicals. Specifically, we had studied the aldolpyrolysis over zeolites and the trans-esterification of vegetable oil with methanol over mixed oxide catalysts. Our research has indicated that the base strength of framework nitrogen in nitrogen substituted zeolites (NH-zeolites) is nearly twice as strong as in standard zeolites. Nitrogen substituted catalysts have been synthesized from several zeolites (including FAU, MFI, BEA, and LTL) using NH3 treatment.

  18. Sulphur condensation influence in Claus catalyst performance.

    Science.gov (United States)

    Mora, R L

    2000-12-01

    The Claus process is an efficient way of removing H(2)S from acid gas streams and this is widely practised in industries such as natural gas processing, oil refining and metal smelting. Increasingly strict pollution control regulations require maximum sulphur recovery from the Claus unit in order to minimise sulphur-containing effluent. The most widely used Claus catalyst in sulphur recovery units is non-promoted spherical activated alumina. Properties associated with optimum non-promoted Claus catalyst performance include high surface area, appropriate pore size distribution and enhanced physical properties. The objective of this paper is to outline a procedure in order to estimate Claus catalyst effectiveness after pore plugging due to sulphur condensation. Catalyst deactivation due to pore plugging by sulphur is modelled employing a Bethe lattice and its corresponding performance is described by means of a modified effectiveness factor. Model results show an improvement in the modified effectiveness factor due to modifications in catalyst porous structure.

  19. Theoretical investigations of olefin metathesis catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Cundari, T.R.; Gordon, M.S. [North Dakota State Univ., Fargo, ND (United States)

    1992-01-01

    An ab initio analysis of the electronic structure of high-valent, transition-metal alkylidenes as models for olefin metathesis catalysts is presented. The catalyst models studied fall into three categories: {open_quotes}new{close_quotes} metathesis catalyst models-tetrahedral M(OH){sup 2}(XH)(CH{sub 2}) complexes; {open_quotes}old{close_quotes} metathesis catalyst models-tetrahedral MCl{sub 2}(Y)(CH{sub 2}) complexes and alkylidene-substituted Mo metathesis catalysts, Mo(OH){sub 2}(NH)(=C(H)Z). The effect on the bonding caused by modification of either the metal, ligands, or alkylidene substitutents is considered. 21 refs., 2 figs., 5 tabs.

  20. MMC-High Propylene Selectivity DCC Catalyst

    Institute of Scientific and Technical Information of China (English)

    Li Zheng; Xie Chaogang; Luo Yibin; Zhao Liuzhou; Shu Xingtian

    2007-01-01

    RIPP has developed the third generation novel DCC catalysts aimed at increasing the propylene yield, named as the MMC series catalysts. This catalyst is of the MFI structure composed of the ZSP zeolite as the main active component, which has higher capability for producing low-carbon olefins, in particular the propylene. The commercial application of this catalyst at SINOPEC Anqing Petrochemical Company has revealed that the adoption of the MMC-2 catalyst has resulted in a 1.6-4.0 percentages increase in propylene yield under basically similar conditions in terms of the feedstock property and process operating regime coupled with reduction in gasoline olefin content and increase in aromatic content to improve the gasoline quality.

  1. Testing commercial catalysts in recycle reactors

    Energy Technology Data Exchange (ETDEWEB)

    Berty, J.M.

    1979-01-01

    Recycle reactors for quality control of catalyst production and for testing new catalysts for known or new processes have the following advantages over tubular reactors: they can reproduce the physical and chemical regime which surrounds the catalyst in a commercial reactor; they can achieve high mass and heat transfer; they exhibit uniform coke deposit; and they provide independence of mass velocity and space velocity. Their disadvantage is the unconventional specification of experiments in terms of discharge concentration which derives from the implicit nature of the basic mathematical relationships. Recycle reactor test methods are outlined for quality control and for testing catalysts, e.g., supported nickel from different manufacturers, for processes whose chemistry is well known. Approaches for testing catalysts for new processes are discussed. The standard recycle reactor developed at Union Carbide Corp. and manufactured by Autoclave Engineers, and several of its modifications are described.

  2. Catalysts for complete oxidation of gaseous fuels

    Energy Technology Data Exchange (ETDEWEB)

    Neyestanaki, A.K.

    1995-12-31

    This thesis presents a study on the complete oxidation of propane, natural gas and the conversion of car exhaust gases over two types of catalysts: (a) knitted silica-fibre supported catalysts and (b) metal-modified ZSM zeolite catalysts. A hybrid textile made up of an organic-inorganic hybrid fibre containing 70 % cellulose and 30 % silicic acid was used as the raw material for preparation of the fibre support for combustion catalysts. The hybrid textile was burnt to obtain a knitted silica-fibre. The changes in the surface area, pore volume and the crystallinity of the obtained support were studied as a function of burning temperature. The stability of the support in steam-rich atmospheres was tested. The knitted silica-fibre obtained by burning the hybrid textile at 1223 K was found to have sufficient strength and high BET specific surface area (140 m{sub 2}/g) to be used as a catalyst support. A series of knitted silica-fibre supported metal oxides (oxides of Co, Ni, Mn, Cr and Cu) and combinations of them, platinum-activated metal oxides (Pt-Co{sub 3}O{sub 4}, Pt-NiO, Pt-MnO{sub 2} and Pt-Cr{sub 2}O{sub 3}) as well as noble metal (Pt, Pd) catalysts were prepared. The location of the metal oxides on the catalyst was studied by SEM equipped with EDXA. The metal oxide was found to be located mostly inside the pores rather than on the exterior surface of the silica-fibre. The catalysts were characterized by XRD, N{sub 2}-physisorption, O{sub 2}-TPD and the chemisorption of propane, carbon monoxide and hydrogen. The activity of the catalysts was tested in the combustion of propane, natural gas and in the conversion of automobile exhaust gases. The effect of residence time and stoichiometry on the conversion behaviour of the catalysts was studied

  3. Catalysts, Protection Layers, and Semiconductors

    DEFF Research Database (Denmark)

    Chorkendorff, Ib

    2015-01-01

    Hydrogen is the simplest solar fuel to produce and in this presentation we shall give a short overview of the pros and cons of various tandem devices [1]. The large band gap semiconductor needs to be in front, but apart from that we can chose to have either the anode in front or back using either...... acid or alkaline conditions. Since most relevant semiconductors are very prone to corrosion the advantage of using buried junctions and using protection layers offering shall be discussed [2-4]. Next we shall discuss the availability of various catalysts for being coupled to these protections layers...... and how their stability may be evaluated [5, 6]. Examples of half-cell reaction using protection layers for both cathode and anode will be discussed though some of recent examples under both alkaline and acidic conditions. Si is a very good low band gap semiconductor and by using TiO2 as a protection...

  4. Fundamental investigations of catalyst nanoparticles

    DEFF Research Database (Denmark)

    Elkjær, Christian Fink

    fundamental understanding of catalytic processes and our ability to make use of that understanding. This thesis presents fundamental studies of catalyst nanoparticles with particular focus on dynamic processes. Such studies often require atomic-scale characterization, because the catalytic conversion takes...... place on the molecular and atomic level. Transmission electron microscopy (TEM) has the ability to image nanostructures with atomic resolution and reveal the atomic configuration of the important nanoparticle surfaces. In the present work, TEM has been used to study nanoparticles in situ at elevated...... different topics, each related to different aspects of nanoparticle dynamics and catalysis. The first topic is the reduction of a homogeneous solid state precursor to form the catalytically active phase which is metal nanoparticles on an inert support. Here, we have reduced Cu phyllosilicate to Cu on silica...

  5. Catalysts derived from waste slag for transesterification

    Institute of Scientific and Technical Information of China (English)

    Xiaowei Zhang; Wei Huang

    2011-01-01

    MgO-CaO/SiO2 solid catalysts derived from waste slag (WS) of metal magnesium plant were prepared.The catalytic performances were evaluated in the transesterification of rapeseed oil with methanol to biodiesel in a 500 mL three-necked reactor under atmospheric pressure.The basic strengh of the catalyst reached 22.0 measured by indicators accroding to Hammett scale.The results show that the MgO-CaO/SiO2 is an excellent catalyst for transesterification, and the conversion of rapeseed oil reach 98% under the optimum condition.

  6. Characterization of three-way automotive catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Kenik, E.A.; More, K.L. [Oak Ridge National Laboratory, TN (United States); LaBarge, W. [General Motors-AC Delco Systems, Flint, MI (United States)] [and others

    1995-05-01

    This has been the second year of a CRADA between General Motors - AC Delco Systems (GM-ACDS) and Martin Marietta Energy Systems (MMES) aimed at improved performance/lifetime of platinum-rhodium based three-way-catalysts (TWC) for automotive emission control systems. While current formulations meet existing emission standards, higher than optimum Pt-Rh loadings are often required. In additionk, more stringent emission standards have been imposed for the near future, demanding improved performance and service life from these catalysts. Understanding the changes of TWC conversion efficiency with ageing is a critical need in improving these catalysts.

  7. Oxide catalysts for oxidation of xylene

    Directory of Open Access Journals (Sweden)

    Kusman Dossumov

    2013-09-01

    Full Text Available Polioxide granulated catalysts based on transition and rare earth metals for oxidative conversion of xylene by oxygen have been investigated. It was defined the effect of the composition and concentration of the active phase of oxide catalysts: Cu-Mn-Ln; Cu-Mn-Ce and Cu-Mn-Nd on the o-xylene oxidation. It was found that the Cu-Mn-Ce catalyst has the highest activity at the concentrations of metals: copper – 3.0%; manganese – 3.0%; cerium – 1.0%.

  8. LC-finer catalyst testing. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Garg, D.; Bronfenbrenner, J.C.

    1983-09-01

    The activity and aging rate of modified Shell 324 Ni-Mo-Al catalyst were studied in ICRC's process development unit (PDU) under SRC-I Demonstration Plant hydroprocessing conditions. The studies determined variations in SRC conversion, hydrocarbon gas production, hydrogen consumption, and heteroatom removal at both constant and increasing reaction temperatures. Samples of spent catalyst were analyzed to ascertain the reasons for catalyst deactivation. Finally, the PDU hydroprocessing results were compared with those generated at Lummus and Wilsonville pilot plants. 14 references, 25 figures, 16 tables.

  9. 40 CFR 90.427 - Catalyst thermal stress resistance evaluation.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Catalyst thermal stress resistance... Gaseous Exhaust Test Procedures § 90.427 Catalyst thermal stress resistance evaluation. (a) The purpose of... catalyst conversion efficiency for Phase 1 engines. The thermal stress is imposed on the test catalyst...

  10. High pressure CO hydrogenation over bimetallic Pt-Co catalysts

    DEFF Research Database (Denmark)

    Christensen, Jakob Munkholt; Medford, Andrew James; Studt, Felix

    2014-01-01

    The potential of bimetallic Pt-Co catalysts for production of higher alcohols in high pressure CO hydrogenation has been assessed. Two catalysts (Pt3Co/SiO2 and PtCo/SiO2) were tested, and the existing literature on CO hydrogenation over Pt-Co catalysts was reviewed. It is found that the catalyst...

  11. Efficient Nd Promoted Rh Catalysts for Vapor Phase Methanol Carbonylation

    Institute of Scientific and Technical Information of China (English)

    Shu Feng ZHANG; Qing Li QIAN; Ping Lai PAN; Yi CHEN; Guo Qing YUAN

    2005-01-01

    A Nd promoted-Rh catalysts supported on polymer-derived carbon beads for vapor-phase methanol carbonylation was developed. Rh-Nd bimetallic catalysts obviously have higher activity than that of supported Rh catalyst under similar reaction condition. The difference between the activity of above two catalyst systems is clearly caused by the intrinsic properties generated by the introduction of Nd.

  12. Supported catalyst systems and method of making biodiesel products using such catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Manhoe; Yan, Shuli; Salley, Steven O.; Ng, K. Y. Simon

    2015-10-20

    A heterogeneous catalyst system, a method of preparing the catalyst system and a method of forming a biodiesel product via transesterification reactions using the catalyst system is disclosed. The catalyst system according to one aspect of the present disclosure represents a class of supported mixed metal oxides that include at least calcium oxide and another metal oxide deposited on a lanthanum oxide or cerium oxide support. Preferably, the catalysts include CaO--CeO.sub.2ZLa.sub.2O.sub.3 or CaO--La.sub.2O.sub.3/CeO.sub.2. Optionally, the catalyst may further include additional metal oxides, such as CaO--La.sub.2O.sub.3--GdOxZLa.sub.2O.sub.3.

  13. Synthesis of Organic Compounds over Selected Types of Catalysts

    Directory of Open Access Journals (Sweden)

    Omar Mohamed Saad Ismail

    2011-05-01

    Full Text Available This study provides an overview for the utilization of different catalytic material in the synthesis of organic compounds for important reactions such as heck reaction, aldol reaction, Diels- Alder and other reactions. Comparisons between multiple catalysts for the same reaction and justifications for developing new catalyzed materials are discussed. The following topics are introduced in this work; (1 solid base catalysts, (2 clay catalysts, (3 palladium catalysts, and (4 catalysts to produce organic compound from CO2. The features of these catalysts a long with the conjugated reactions and their selectivity are explained in details, also, some alternatives for toxic or polluting catalysts used in industry are suggested.

  14. Enhancement of water-gas shift reaction efficiency: catalysts and the catalyst bed arrangement

    Energy Technology Data Exchange (ETDEWEB)

    Baronskaya, Natal' ya A; Minyukova, Tat' yana P; Khassin, Aleksandr A; Yurieva, Tamara M; Parmon, Valentin N [G.K. Boreskov Institute of Catalysis, Siberian Branch of the Russian Academy of Sciences, Novosibirsk (Russian Federation)

    2010-12-29

    The results of studies devoted to the search for catalysts of water-gas shift (WGS) reaction that are highly active in a wide temperature interval are generalized. New compositions based on traditional and alternative, as regards the chemical composition, catalysts of high- and low-temperature WGS reaction are considered in detail. The single-stage arrangement of WGS reaction ensuring small temperature gradients in the radial direction of the catalyst bed are discussed.

  15. Propene metathesis over silica-supported tungsten oxide catalyst-catalyst induction mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Basrur, A.G.; Patwardhan, S.R.; Vyas, S.N. (Indian Inst. of Tech., Bombay (India))

    1991-01-01

    The propene metathesis reaction was studied from the point of view of elucidating the mechanism of catalyst induction and establishing conditions for maximum activity. Instrumental techniques such as ESR, IR, and TPD were used to study the various aspects. During catalyst induction, trace quantities of acetone and acetaldehyde were detected in the product stream, indicating that lattice oxygen from tungsten oxide might be responsible for these products. Induction appeared to proceed via two steps since pretreatment of the catalyst with nitrogen and hydrogen yielded a decreased amount of acetone in the latter case whereas acetaldehyde remained unaffected. ESR studies indicated some interaction between tungsten oxide and silica at the catalyst preparatory stage as well as stabilization of reduced tungsten species on the catalyst after its use and regeneration. Catalyst activity appeared to depend on conditions of pretreatment. Change in nitrogen pretreatment temperature from 500 to 600{sup o}C resulted in transition from strong to negligible external mass transfer behavior of the catalyst. TPD studies in this context showed possible loss of lattice oxygen from tungsten oxide under the above-mentioned conditions of catalyst pretreatment. ESR studies indicated the reduction of WO{sub 3} to a nonstoichiometric oxidation state. Hence catalytic activity appears to be related to the nonstoichiometric state of tungsten oxide, which may be WO{sub 2.9} (as deduced from the blue-violet color of the used catalyst).

  16. Reactivity of pi-complexes of Ti, V, and Nb towards dithioacetic acid: Synthesis and structure of novel metal sulfur-containing complexes

    Science.gov (United States)

    Duraj, Stan A.; Andras, Maria T.; Hepp, Aloysius F.

    1990-01-01

    In order to use sulfur-containing resources economically and with minimal environmental damage, it is important to understand the desulfurization processes. Hydrodesulfurization, for example, is carried out on the surface of a heterogeneous metal sulfide catalyst. Studies of simple, soluble inorganic systems provide information regarding the structure and reactivity of sulfur-containing compounds with metal complexes. Further, consistent with recent trends in materials chemistry, many model compounds warrant further study as catalyst precursors. The reactivity of low-valent organometallic sandwich pi-complexes toward dithiocarboxylic acids is described. For example, treatment of bisbenzene vanadium with CH3CSSH affords a divanadium tetrakis(dithioacetate) complex. The crystallographically determined V-V bond distance, 2.800(2), is nearly the same as the V-V bond distance in a V(mu-nu squared-S2)2V' unit in the mineral patonite (VS4)n. The stability of the V2S4 core in the dimer is demonstrated by evidence of V2S4(+) in the mass spectrum (70 eV, solid probe) of the vanadium dimer. Several other systems relevant to HDS catalysis are also discussed.

  17. FCC Catalysts to Meet Demand of New Era

    Institute of Scientific and Technical Information of China (English)

    Yu Daping

    2008-01-01

    The CGP series FCC catalysts for manufacture of clean gasoline and propylene and the catalyst RSC-2006 for processing inferior residuum with high yield of light distillates are novel catalysts jointly developed by Qilu Catalyst Branch Company of SINOPEC Corp. and the Research Institute of Petroleum Processing (RIPP). The results of commercial application of these catalysts have revealed that they can satisfactorily meet the requirements for environmental protection, good economic benefits and capability for processing inferior FCC feed under new circumstances.

  18. Assessment on Commercial Application of Novel S-RHT Catalysts

    Institute of Scientific and Technical Information of China (English)

    Bian Fengming; Wen Huixin

    2004-01-01

    This article refers to the commercial application assessment of the novel S-RHT catalysts.The application outcome has shown that the catalysts loading was reduced with its performance kept at the original level at the initial and middle stages of operation. The performance of catalysts at the end of operation was analyzed, and factors affecting the performance of the novel catalysts at the end of run were identified to facilitate further improvement of the said catalysts.

  19. Preparative characteristics of hydrophobic polymer catalyst for the tritium removal

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Hee Suk; Choi, H. J.; Lee, H. S.; Ahn, D. H.; Kim, K. R.; Paek, S. W.; Kim, J. G.; Chung, H. S

    2001-05-01

    The optimum method for the fabrication of hydrophobic catalyst was selected and the apparatuses for the preparation of catalyst support with high yield was developed for the large scale production. Also, we summarized the method of improving the physical property of the catalyst support, the loading characteristics of Pt metal as a catalyst, and the characteristics of the apparatus for the fabrication of the catalysts on a large scale.

  20. Mordenite - Type Zeolite SCR Catalysts with Iron or Copper

    DEFF Research Database (Denmark)

    2012-01-01

    Cu/mordenite catalysts were found to be highly active for the SCR of NO with NH3 and exhibited high resistance to alkali poisoning. Redox and acidic properties of Cu/mordenite were well preserved after poisoning with potassium unlike that of vanadium catalysts. Fe-mordenite catalysts also reveale...... to be essential requirements for the high alkali resistance. Mordenite-type zeolite based catalysts could therefore be attractive alternatives to conventional SCR catalysts for biomass fired power plant flue gas treatment....

  1. Highly sensitive silicon microreactor for catalyst testing

    DEFF Research Database (Denmark)

    Henriksen, Toke Riishøj; Olsen, Jakob Lind; Vesborg, Peter Christian Kjærgaard;

    2009-01-01

    by directing the entire gas flow through the catalyst bed to a mass spectrometer, thus ensuring that nearly all reaction products are present in the analyzed gas flow. Although the device can be employed for testing a wide range of catalysts, the primary aim of the design is to allow characterization of model...... catalysts which can only be obtained in small quantities. Such measurements are of significant fundamental interest but are challenging because of the low surface areas involved. The relationship between the reaction zone gas flow and the pressure in the reaction zone is investigated experimentally......, it is found that platinum catalysts with areas as small as 15 mu m(2) are conveniently characterized with the device. (C) 2009 American Institute of Physics. [doi:10.1063/1.3270191]...

  2. Synthesis and Understanding of Novel Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Stair, Peter C. [Northwestern University

    2013-07-09

    The research took advantage of our capabilities to perform in-situ and operando Raman spectroscopy on complex systems along with our developing expertise in the synthesis of uniform, supported metal oxide materials to investigate relationships between the catalytically active oxide composition, atomic structure, and support and the corresponding chemical and catalytic properties. The project was organized into two efforts: 1) Synthesis of novel catalyst materials by atomic layer deposition (ALD). 2) Spectroscopic and chemical investigations of coke formation and catalyst deactivation. ALD synthesis was combined with conventional physical characterization, Raman spectroscopy, and probe molecule chemisorption to study the effect of supported metal oxide composition and atomic structure on acid-base and catalytic properties. Operando Raman spectroscopy studies of olefin polymerization leading to coke formation and catalyst deactivation clarified the mechanism of coke formation by acid catalysts.

  3. Nanostructured hydrotreating catalysts for electrochemical hydrogen evolution.

    Science.gov (United States)

    Morales-Guio, Carlos G; Stern, Lucas-Alexandre; Hu, Xile

    2014-09-21

    Progress in catalysis is driven by society's needs. The development of new electrocatalysts to make renewable and clean fuels from abundant and easily accessible resources is among the most challenging and demanding tasks for today's scientists and engineers. The electrochemical splitting of water into hydrogen and oxygen has been known for over 200 years, but in the last decade and motivated by the perspective of solar hydrogen production, new catalysts made of earth-abundant materials have emerged. Here we present an overview of recent developments in the non-noble metal catalysts for electrochemical hydrogen evolution reaction (HER). Emphasis is given to the nanostructuring of industrially relevant hydrotreating catalysts as potential HER electrocatalysts. The new syntheses and nanostructuring approaches might pave the way for future development of highly efficient catalysts for energy conversion.

  4. Heterogeneous Metal Catalysts for Oxidation Reactions

    Directory of Open Access Journals (Sweden)

    Md. Eaqub Ali

    2014-01-01

    Full Text Available Oxidation reactions may be considered as the heart of chemical synthesis. However, the indiscriminate uses of harsh and corrosive chemicals in this endeavor are threating to the ecosystems, public health, and terrestrial, aquatic, and aerial flora and fauna. Heterogeneous catalysts with various supports are brought to the spotlight because of their excellent capabilities to accelerate the rate of chemical reactions with low cost. They also minimize the use of chemicals in industries and thus are friendly and green to the environment. However, heterogeneous oxidation catalysis are not comprehensively presented in literature. In this short review, we clearly depicted the current state of catalytic oxidation reactions in chemical industries with specific emphasis on heterogeneous catalysts. We outlined here both the synthesis and applications of important oxidation catalysts. We believe it would serve as a reference guide for the selection of oxidation catalysts for both industries and academics.

  5. Environmentally benign catalysts for clean organic reactions

    CERN Document Server

    Patel, Anjali

    2013-01-01

    Heterogeneous catalysis attracts researchers and industry because it satisfies most of green chemistry's requirements. Emphasizing the development of third generation catalysts, this book surveys trends and opportunities in academic and industrial research.

  6. Brazilian experience using high-dose sequential therapy (HDS followed by autologous hematopoietic stem cell transplantation (ASCT for malignant lymphomas Experiência brasileira utilizando terapia sequencial de alta dose seguido de transplante autólogo de célula-tronco hematopoética para linfomas malignos

    Directory of Open Access Journals (Sweden)

    Cármino A. de Souza

    2009-08-01

    Full Text Available Using the overall survival (OS, disease free survival (DFS and progression free survival (PFS, as well as associated toxicity, the purpose of this work was to evaluate the effectiveness of HDS followed by ASCT as salvage therapy. A retrospective analysis was performed of 106 patients with high grade non-Hodgkin lymphoma receiving HDS followed by ASCT, between 1998 and 2006. Median age was 45 years (Range: 8-65, with 66 (62% men. Histopathological classification was: 78% DLBCL patients, 12% T and anaplastic and 9% Mantle cell lymphomas; 87% had B cell and 12% T cell lymphomas; 83% were stage III-IV (Ann Arbor Staging, 63% had B symptoms, 32% had bone marrow involvement, 62% bulky disease and 42% high-intermediate or high risk IPI. After HDCY, 9 patients died, 7 from toxicity and 2 from sepsis. Eighty patients underwent ASCT, 47% were in complete remission (CR and 15% died, all from toxicity. Their OS was 45% over 8 years. During the follow-up, another 35 patients died [4 CR, 1 partial response (PR, 2 relapsed disease (RD and 28 disease progression (DP], 11 (31% had not performed ASCT. OS was 37%; DFS was 49% and PFS 28%. OS by diagnosis was 42% for DLBCL, 40% for T-cell (8 y and 20% for Mantle Cell (6 y (P=NS. OS by B symptom patients was 22% vs. 58% (P=0.002 and PFS was 23% vs. 37% (P=0.03. Patients who achieved CR after HDCY (38 had significantly better OS and PFS (38% and 17% than patients who remained in DP (PA proposta deste trabalho foi avaliar a eficácia da HDS seguida do transplante autólogo como terapia de salvamento através da sobrevida global, livre de doença e livre de progressão bem como sua toxicidade. Realizou-se estudo retrospectivo com 106 pacientes com LNH de alto grau de malignidade entre 1998 e 2006. A mediana de idade foi 45 anos (8-65; 62% homens; DLBCL, 78%; 12%, T e anaplásico e 9%, linfoma da zona do manto; 87%, células B; 83% estádios III-IV; 63% com sintomas B; 32% com infiltração da medula óssea ao diagn

  7. Bifunctional Catalysts for CO2 Reduction

    Science.gov (United States)

    2014-09-30

    dioxide reduction catalysis . (SA 1 – Catalyst candidate synthesis) As outlined in the original proposal, ligand platforms have been synthesized to...was limited to outer-sphere electron transfer (necessary oxidation potentials for catalysis > –2.1 V vs. [Cp2Fe] +/0). Thus, we pursued two...to heterogeneous Fischer-Tropsch13 catalysts. This reactivity must also be compared with mononuclear early transition metal ligands that require

  8. Atomistic Processes of Catalyst Degradation

    Energy Technology Data Exchange (ETDEWEB)

    None

    2004-11-27

    The purpose of this cooperative research and development agreement (CRADA) between Sasol North America, Inc., and the oak Ridge National Laboratory (ORNL) was to improve the stability of alumina-based industrial catalysts through the combination of aberration-corrected scanning transmission electron microscopy (STEM) at ORNL and innovative sample preparation techniques at Sasol. Outstanding progress has been made in task 1, 'Atomistic processes of La stabilization'. STEM investigations provided structural information with single-atom precision, showing the lattice location of La dopant atoms, thus enabling first-principles calculations of binding energies, which were performed in collaboration with Vanderbilt University. The stabilization mechanism turns out to be entirely due to a particularly strong binding energy of the La tom to the {gamma}-alumina surface. The large size of the La atom precludes incorporation of La into the bulk alumina and also strains the surface, thus preventing any clustering of La atoms. Thus highly disperse distribution is achieved and confirmed by STEM images. la also affects relative stability of the exposed surfaces of {gamma}-alumina, making the 100 surface more stable for the doped case, unlike the 110 surface for pure {gamma}-alumina. From the first-principles calculations, they can estimate the increase in transition temperature for the 3% loading of La used commercially, and it is in excellent agreement with experiment. This task was further pursued aiming to generate useable recommendations for the optimization of the preparation techniques for La-doped aluminas. The effort was primarily concentrated on the connection between the boehmitre-{gamma}-Al{sub 2}O{sub 3} phase transition (i.e. catalyst preparation) and the resulting dispersion of La on the {gamma}-Al{sub 2}O{sub 3} surface. It was determined that the La distribution on boehmite was non-uniform and different from that on the {gamma}-Al{sub 2}O{sub 3} and thus

  9. Deactivation and poisoning of fuel cell catalysts

    Science.gov (United States)

    Ross, P. N., Jr.

    1985-06-01

    The deactivation and poisoning phenomena reviewed are: the poisoning of anode (fuel electrode) catalyst by carbon monoxide and hydrogen sulfide; the deactivation of the cathode (air electrode) catalyst by sintering; and the deactivation of the cathode by corrosion of the support. The anode catalyst is Pt supported on a conductive, high area carbon black, usually at a loading of 10 w/o. This catalyst is tolerant to some level of carbon monoxide or hydrogen sulfide or both in combination, the level depending on temperature and pressure. Much less is known about hydrogen sulfide poisoning. Typical tolerance levels are 2% CO, and 10 ppM H2S. The cathode catalyst is typically Pt supported on a raphitic carbon black, usually a furnace black heat-treated to 2700 C. The Pt loading is typically 10 w/o, and the dispersion (or percent exposed) as-prepared is typically 30%. The loss of dispersion in use depends on the operational parameters, most especially the cathode potential history, i.e., higher potentials cause more rapid decrease in dispersion. The mechanism of loss of dispersion is not well known. The graphitic carbon support corrodes at a finite rate that is also potential dependent. Support corrosion causes thickening of the electrolyte film between the gas pores and the catalyst particles, which in turn causes increased diffusional resistance and performance loss.

  10. Germanium nanowires grown using different catalyst metals

    Energy Technology Data Exchange (ETDEWEB)

    Gouveia, R.C., E-mail: riama@ifsp.edu.br [Departamento de Física – NanO Lab, Universidade Federal de São Carlos, Rod. Washington Luís, Km 235 – SP 310, São Carlos, CEP 13565-905 (Brazil); Área de Ciências, Instituto Federal de Educação Ciência e Tecnologia de São Paulo, Rua Américo Ambrósio, 269, Jd. Canaã, Sertãozinho, CEP 14169-263 (Brazil); Kamimura, H.; Munhoz, R.; Rodrigues, A.D. [Departamento de Física – NanO Lab, Universidade Federal de São Carlos, Rod. Washington Luís, Km 235 – SP 310, São Carlos, CEP 13565-905 (Brazil); Leite, E.R. [Departamento de Química – LIEC, Universidade Federal de São Carlos, São Carlos, CEP 13565-905 (Brazil); Chiquito, A.J. [Departamento de Física – NanO Lab, Universidade Federal de São Carlos, Rod. Washington Luís, Km 235 – SP 310, São Carlos, CEP 13565-905 (Brazil)

    2016-11-01

    Germanium nanowires have been synthesized by the well known vapor-liquid-solid growth mechanism using gold, silver, cooper, indium and nickel as catalyst metals. The influence of metal seeds on nanowires structural and electronic transport properties was also investigated. Electron microscopy images demonstrated that, despite differences in diameters, all nanowires obtained presented single crystalline structures. X-ray patterns showed that all nanowires were composed by germanium with a small amount of germanium oxide, and the catalyst metal was restricted at the nanowires' tips. Raman spectroscopy evidenced the long range order in the crystalline structure of each sample. Electrical measurements indicated that variable range hopping was the dominant mechanism in carrier transport for all devices, with similar hopping distance, regardless the material used as catalyst. Then, in spite of the differences in synthesis temperatures and nanowires diameters, the catalyst metals have not affected the composition and crystalline quality of the germanium nanowires nor the carrier transport in the germanium nanowire network devices. - Highlights: • Ge nanowires were grown by VLS method using Au, Ag, Cu, In and Ni as catalysts. • All nanowires presented high single crystalline quality and long range order. • Devices showed semiconducting behavior having VRH as dominant transport mechanism. • The metal catalyst did not influence structural properties or the transport mechanism.

  11. Catalysts for the Selective Oxidation of Methanol

    Directory of Open Access Journals (Sweden)

    Catherine Brookes

    2016-06-01

    Full Text Available In industry, one of the main catalysts typically employed for the selective oxidation of methanol to formaldehyde is a multi-component oxide containing both bulk Fe2(MoO43 and excess MoO3. It is thought that the excess MoO3 primarily acts to replace any molybdenum lost through sublimation at elevated temperatures, therefore preventing the formation of an unselective Fe2O3 phase. With both oxide phases present however, debate has arisen regarding the active component of the catalyst. Work here highlights how catalyst surfaces are significantly different from bulk structures, a difference crucial for catalyst performance. Specifically, Mo has been isolated at the surface as the active surface species. This leaves the role of the Fe in the catalyst enigmatic, with many theories postulated for its requirement. It has been suggested that the supporting Fe molybdate phase enables lattice oxygen transfer to the surface, to help prevent the selectivity loss which would occur in the resulting oxygen deficit environment. To assess this phenomenon in further detail, anaerobic reaction with methanol has been adopted to evaluate the performance of the catalyst under reducing conditions.

  12. Carbon-based metal-free catalysts

    Science.gov (United States)

    Liu, Xien; Dai, Liming

    2016-11-01

    Metals and metal oxides are widely used as catalysts for materials production, clean energy generation and storage, and many other important industrial processes. However, metal-based catalysts suffer from high cost, low selectivity, poor durability, susceptibility to gas poisoning and have a detrimental environmental impact. In 2009, a new class of catalyst based on earth-abundant carbon materials was discovered as an efficient, low-cost, metal-free alternative to platinum for oxygen reduction in fuel cells. Since then, tremendous progress has been made, and carbon-based metal-free catalysts have been demonstrated to be effective for an increasing number of catalytic processes. This Review provides a critical overview of this rapidly developing field, including the molecular design of efficient carbon-based metal-free catalysts, with special emphasis on heteroatom-doped carbon nanotubes and graphene. We also discuss recent advances in the development of carbon-based metal-free catalysts for clean energy conversion and storage, environmental protection and important industrial production, and outline the key challenges and future opportunities in this exciting field.

  13. Hydrocarbon conversion process and catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Hoek, A.; Huizinga, T.; Maxwell, I.E.

    1989-08-15

    This patent describes a process for hydrocracking hydrocarbon oils into products of lower average molecular weight and lower average boiling point. It comprises contacting hydrocarbon oil at a temperature between 250{sup 0}C and 500{sup 0}C and a pressure up to 300 bar in the presence of hydrogen with a catalyst consisting essentially of a Y zeolite modified to have a unit cell size below 24.40 A, a water adsorption capacity (at 25{sup 0}C and a rho/rho/sub o/ value of 0.2) of between 10% and 15% by weight of the zeolite and a pore volume of at least 0.25 ml/g wherein between 10% and 60% of the total pore volume is made up of pores having a diameter of at least 8 nm; am amorphous cracking component, a binder and at least one hydrogenation component selected from the group consisting of a Group VI metal, a Group VIII metal and mixtures thereof.

  14. CO methanation over supported bimetallic Ni-Fe catalysts: From computational studies towards catalyst optimization

    DEFF Research Database (Denmark)

    Kustov, Arkadii; Frey, Anne Mette; Larsen, Kasper Emil

    2007-01-01

    DFT calculations combined with a computational screening method have previously shown that bimetallic Ni-Fe alloys should be more active than the traditional Ni-based catalyst for CO methanation. That was confirmed experimentally for a number of bimetallic Ni-Fe catalysts supported on MgAl2O4. He...

  15. The capacity of modified nickel catalysts derived from discharged catalyst of fertilizer plants for NOx treatment

    Science.gov (United States)

    Ha, T. M. P.; Luong, N. T.; Le, P. N.

    2016-11-01

    In Vietnam for recent years, a large amount of hazardous waste containing nickel (Ni) derived from discharged catalyst of fertilizer plants has caused environmental problems in landfill overloading and the risk of soil or surface water sources pollution. Taking advantage of discharged catalyst, recycling Ni components and then synthesizing new catalysts apply for mono-nitrogen oxides (NOx) treatments is an approach to bring about both economic and environmental benefits. This study was carried out with the main objective: Evaluate the performance of modified catalysts (using recovered Ni from the discharged RKS-2-7H catalyst of Phu My Fertilizer Plant) on NOx treatment. The catalysts was synthesized and modified with active phases consist of recovered Ni and commercial Barium oxide (BaO), Manganese dioxide (MnO2) / Cerium (IV) oxide (CeO2) on the support Aluminium oxide (γ-Al2O3). The results show that the modified catalysts with Ni, Ba, Ce was not more beneficial for NOx removal than which with Ni, Ba, Mn. 98% NOx removal at 350°C with the start temperature at 115°C and the T60 value at 307°C can be obtained with 10Ni10Ba10Mn/Al catalyst.

  16. Catalytic Transformation of Ethylbenzene over Y-Zeolite-based Catalysts

    KAUST Repository

    Al-Khattaf, Sulaiman

    2008-11-19

    Catalytic transformation of ethylbenzene (EB) has been investigated over ultrastable Y (USY)-zeolite-based catalysts in a novel riser simulator at different operating conditions. The effect of reaction conditions on EB conversion is reported. The USY catalyst (FCC-Y) was modified by steaming to form a significantly lower acidity catalyst (FCC-SY). The current study shows that the FCC-SY catalyst favors EB disproportionation more than cracking. A comparison has been made between the results of EB conversion over the lowly acidic catalyst (FCC-SY) and the highly acidic catalyst (FCC-Y) under identical conditions. It was observed that increase in catalyst acidity favored cracking of EB at the expense of disproportionation. Kinetic parameters for EB disappearance during disproportionation reaction over the FCC-SY catalyst were calculated using the catalyst activity decay function based on time on stream (TOS). © 2008 American Chemical Society.

  17. Development of Novel Resid Hydrometallization Catalyst RDM-3

    Institute of Scientific and Technical Information of China (English)

    Hu Dawei; Niu Chuanfeng; Yang Qinghe; Liu Tao

    2007-01-01

    Based on the reaction mechanism of resid hydrodemetallization,a new catalyst carrier was designed and prepared.As compared with the similar type of catalyst carder,the said new carrier featured a higher pore volume,a larger pore diameter and a weaker surface acidity,which could improve the diffusion performance and stable reaction performance of the catalyst.The active metal components were loaded on the said carrier by a new technique for better metal dispersion,thus the impurity removal rate of the new catalyst,RDM-3,was improved significantly.The commercial test of the RDM-3 catalyst showed that the process of catalyst preparation was stable,the catalyst performance was slightly better than the catalyst prepared in the lab,therefore,the catalyst could be manufactured in commercial scale.

  18. Interaction between Nafion ionomer and noble metal catalyst for PEMFCs

    DEFF Research Database (Denmark)

    Andersen, Shuang Ma

    The implement of polymer impregnation in electrode structure (catalyst layer) decreasing the noble metal catalyst loading by a factor of ten , , is one of the essential mile stones in the evolution of Proton Exchange Membrane Fuel Cells’ development among the application of catalyst support...... and electrode deposition etc. In fuel cell reactions, both electrons and protons are involved. Impregnation of Nafion ionomer in catalyst layer effectively increases the proton-electron contact, enlarge the reaction zone, extend the reaction from the surface to the entire electrode. Therefore, the entire...... catalyst layer conducts both electrons and protons so that catalyst utilization in the layer is improved dramatically. The catalyst layer will in turn generate and sustain a higher current density. One of the generally adapted methods to impregnate Nafion into the catalyst layer is to mix the catalysts...

  19. Towards the Rational Design of Nanoparticle Catalysts

    Science.gov (United States)

    Dash, Priyabrat

    This research is focused on development of routes towards the rational design of nanoparticle catalysts. Primarily, it is focused on two main projects; (1) the use of imidazolium-based ionic liquids (ILs) as greener media for the design of quasi-homogeneous nanoparticle catalysts and (2) the rational design of heterogeneous-supported nanoparticle catalysts from structured nanoparticle precursors. Each project has different studies associated with the main objective of the design of nanoparticle catalysts. In the first project, imidazolium-based ionic liquids have been used for the synthesis of nanoparticle catalysts. In particular, studies on recyclability, reuse, mode-of-stability, and long-term stability of these ionic-liquid supported nanoparticle catalysts have been done; all of which are important factors in determining the overall "greenness" of such synthetic routes. Three papers have been published/submitted for this project. In the first publication, highly stable polymer-stabilized Au, Pd and bimetallic Au-Pd nanoparticle catalysts have been synthesized in imidazolium-based 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM]PF6) ionic liquid (Journal of Molecular Catalysis A: Chemical, 2008, 286, 114). The resulting nanoparticles were found to be effective and selective quasi-homogeneous catalysts towards a wide-range of hydrogenation reactions and the catalyst solution was reused for further catalytic reactions with minimal loss in activity. The synthesis of very pure and clean ILs has allowed a platform to study the effects of impurities in the imidazolium ILs on nanoparticle stability. In a later study, a new mode of stabilization was postulated where the presence of low amounts of 1-methylimidazole has substantial effects on the resulting stability of Au and Pd-Au nanoparticles in these ILs (Chemical Communications, 2009, 812). In further continuation of this study, a comparative study involving four stabilization protocols for nanoparticle

  20. Methanol conversion to hydrocarbons using modified clinoptilolite catalysts. Investigation of catalyst lifetime and reactivation

    Energy Technology Data Exchange (ETDEWEB)

    Hutchings, G.J.; Themistocleous, T.; Copperthwaite, R.G.

    1988-10-17

    A study of the deactivation and reactivation of modified clinoptilolite catalysts for methanol conversion to hydrocarbons is reported. Clinoptilolite catalysts, modified by either ammonium ion exchange or hydrochloric acid treatment, exhibit a short useful catalyst lifetime for this reaction (ca. 2-3 h) due to a high rate of coke deposition (3-5.10/sup -3/ g carbon/g catalyst/h). A comparative study of reactivation using oxygen, nitrous oxide and ozone/oxygen as oxidants indicated that nitrous oxide reactivation gives improved catalytic performance when compared to the activity and lifetime of the fresh catalyst. Both oxygen and ozone/oxygen were found to be ineffective for the reactivation of clinoptilolite. Initial studies of in situ on-line reactivation are also described. 3 figs., 15 refs., 4 tabs.

  1. Optimal catalyst curves: Connecting density functional theory calculations with industrial reactor design and catalyst selection

    DEFF Research Database (Denmark)

    Jacobsen, C.J.H.; Dahl, Søren; Boisen, A.

    2002-01-01

    For ammonia synthesis catalysts a volcano-type relationship has been found experimentally. We demonstrate that by combining density functional theory calculations with a microkinetic model the position of the maximum of the volcano curve is sensitive to the reaction conditions. The catalytic...... ammonia synthesis activity, to a first approximation, is a function only of the binding energy of nitrogen to the catalyst. Therefore, it is possible to evaluate which nitrogen binding energy is optimal under given reaction conditions. This leads to the concept of optimal catalyst curves, which illustrate...... the nitrogen binding energies of the optimal catalysts at different temperatures, pressures, and synthesis gas compositions. Using this concept together with the ability to prepare catalysts with desired binding energies it is possible to optimize the ammonia process. In this way a link between first...

  2. Sites and reactivity of sulfides in hydro-treatment catalysis: theoretical ab-initio study; Sites et reactivite des sulfures en catalyse d`hydrotraitement: etude theorique ab-initio

    Energy Technology Data Exchange (ETDEWEB)

    Raybaud, P.

    1998-10-28

    Ab-initio calculations within the DFT and GGA have been carried out in an attempt to understand better which property sets the activity of transition metal sulfides (TMS) in the hydro-desulfurization reaction (HDS), a most important step in the refining of crude oil. A systematic study of the structural cohesive and electronic properties of more than thirty bulk TMS has allowed us to find a new simple relationship between the experimental catalytic activities known in HDS, and the properly defined sulfur-metal (S-M) bond energy. On this volcano curve reminiscent of the Sabatier principles, ionic metallic sulfides (as Ni{sub 3}S{sub 2}, Ci{sub 9}S{sub 8}) exhibit the weakest bonds whereas ion-covalent semi-conductors (as MoS{sub 2}) exhibit the strongest bonds: the highest activities correspond to intermediate bond strengths (RuS{sub 2}). Our study of the electronic structure of the MoS{sub 2} edge surfaces has revealed acceptor surface states localized on Coordinatively Unsaturated Mo ions and the significance of those states for the activation of hetero-aromatic molecules like thiophene. On such surfaces, the energetic profiles we establish for the thiophene HDS reaction point out the surface anionic vacancy regeneration steps as rate determining. We have calculated the optimal positions of Co (Ni) in decoration on the MoS{sub 2} edge planes, in excellent agreement with available EXAFS data on real catalysts. Introducing the promoter Co (Ni) induces a lower optimal sulfur coverage and a lower surface S-M bond strength in proportion of the Co (Ni) coverage, and lower for Ni than for Co. Simplified energy profiles for the thiophene HDS reactions on promoted (101-bar 0) surfaces show that the C-S scission step is likely to become rate determining. Our results show altogether that bulk and surface S-M strengths in TMS systems show similar trends, insofar as they are primarily determined by the local electronic structure. (author)

  3. Synthesis H-Zeolite catalyst by impregnation KI/KIO3 and performance test catalyst for biodiesel production

    Science.gov (United States)

    Widayat, W.; Rizky Wicaksono, Adit; Hakim Firdaus, Lukman; Okvitarini, Ndaru

    2016-02-01

    The objective of this research is to produce H-catalyst catalyst that was impregnated with KI/KIO3. The catalyst was analyzed about surface area, X-Ray Diffraction (XRD) and performance test of catalyst for biodiesel production. An H-Zeolite catalyst was synthesized from natural zeolite with chemical treatment processing, impregnation KI/KIO3 and physical treatment. The results shows that the surface area of the catalyst by 27.236 m2/g at a concentration of 5% KI. XRD analysis shows peak 2-θ at 23.627o indicating that KI was impregnated on H-zeolite catalyst. The catalyst was tested in production of biodiesel using palm oil with conventional methods for 3 hour at temperature of 70-80 oC. The result for conversion Fatty Acid Methyl Ester (FAME) reached maximum value on 87.91% under production process using catalyst 5% KIO3-H zeolite.

  4. Development and Application of CDOS Series Catalysts for Bottoms Cracking

    Institute of Scientific and Technical Information of China (English)

    Wang Mingjin; Xu Mingde; Zhu Yuxia

    2013-01-01

    Development of CDOS catalyst for bottoms cracking is based on DOSY zeolite, which is characterized by high metal tolerance. The results of DOSY tests have shown that the catalyst has better activity retention at high metal content in the feed. The performance of catalyst tested in the bench scale was superior over that of the reference catalyst. The results of catalyst application have shown that the CDOS series catalysts have better bottoms cracking activity, high metal tolerance, excellent dry gas selectivity, and enhanced liquid yield.

  5. Catalyst and electrode research for phosphoric acid fuel cells

    Science.gov (United States)

    Antoine, A. C.; King, R. B.

    1987-01-01

    An account is given of the development status of phosphoric acid fuel cells' high performance catalyst and electrode materials. Binary alloys have been identified which outperform the baseline platinum catalyst; it has also become apparent that pressurized operation is required to reach the desired efficiencies, calling in turn for the use of graphitized carbon blacks in the role of catalyst supports. Efforts to improve cell performance and reduce catalyst costs have led to the investigation of a class of organometallic cathode catalysts represented by the tetraazaannulenes, and a mixed catalyst which is a mixture of carbons catalyzed with an organometallic and a noble metal.

  6. Characterization of three-way automotive catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Kenik, E.A.; More, K.L. [Oak Ridge National Lab., TN (United States); LaBarge, W. [Delphi Automotive Systems, Flint, MI (United States)] [and others

    1997-04-01

    The CRADA between Delphi Automotive Systems (Delphi; formerly General Motors - AC Delco, Systems) and Lockheed Martin Energy Research (LMER) on automotive catalysts was completed at the end of FY96, after a ten month, no-cost extension. The CRADA was aimed at improved performance and lifetime of noble metal based three-way-catalysts (TWC), which are the primary catalytic system for automotive emission control systems. While these TWC can meet the currently required emission standards, higher than optimum noble metal loadings are often required to meet lifetime requirements. In addition, more stringent emission standards will be imposed in the near future, demanding improved performance and service life from these catalysts. Understanding the changes of TWC conversion efficiency with ageing is a critical need in improving these catalysts. Initially in a fresh catalyst, the active material is often distributed on a very fine scale, approaching single atoms or small atomic clusters. As such, a wide range of analytical techniques have been employed to provide high spatial resolution characterization of the evolving state of the catalytic material.

  7. New catalysts for exhaust gas cleaning

    Energy Technology Data Exchange (ETDEWEB)

    Haerkoenen, M. [Kemira Metalkat Oy, Oulu (Finland)

    1996-12-31

    Major challenge for future catalyst systems was to develop thermally more stable washcoats for close coupled operating conditions and for engines operating under high speed and load conditions. To design these future emission systems extensive research and development was undertaken to develop methods to disperse and stabilize the key catalytic materials for operation at much higher temperatures. Second priority was to design catalysts that are more effective under low temperature exhaust conditions and have improved oxygen storage properties in the washcoats. Incorporating new materials and modified preparation technology a new generation of metallic catalyst formulations emerged, those being trimetallic K6 (Pt:Pd:Rh and bimetallic K7) (Pd+Pd:Rh). The target was to combine the best property of Pt:Rh (good NO{sub x} reduction) with that of the good HC oxidation activity of Pd and to ensure that precious metal/support interactions were positively maintained. Both K6 and K7 concepts contain special catalyst structures with optimized washcoat performance which can be brick converter configuration. Improvement in light-off, thermal stability and transient performance with these new catalyst formulations have clearly been shown in both laboratory and vehicle testing. (author) (20 refs.)

  8. Thermally Stable, Latent Olefin Metathesis Catalysts

    Science.gov (United States)

    Thomas, Renee M.; Fedorov, Alexey; Keitz, Benjamin K.

    2011-01-01

    Highly thermally stable N-aryl,N-alkyl N-heterocyclic carbene (NHC) ruthenium catalysts were designed and synthesized for latent olefin metathesis. These catalysts showed excellent latent behavior toward metathesis reactions, whereby the complexes were inactive at ambient temperature and initiated at elevated temperatures, a challenging property to achieve with second generation catalysts. A sterically hindered N-tert-butyl substituent on the NHC ligand of the ruthenium complex was found to induce latent behavior toward cross-metathesis reactions, and exchange of the chloride ligands for iodide ligands was necessary to attain latent behavior during ring-opening metathesis polymerization (ROMP). Iodide-based catalysts showed no reactivity toward ROMP of norbornene-derived monomers at 25 °C, and upon heating to 85 °C gave complete conversion of monomer to polymer in less than 2 hours. All of the complexes were very stable to air, moisture, and elevated temperatures up to at least 90 °C, and exhibited a long catalyst lifetime in solution at elevated temperatures. PMID:22282652

  9. Chemical interactions in multimetal/zeolite catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Sachtler, W.M.H.

    1992-12-21

    Research is proposed on two groups of zeolite based catalysts that contain two transition elements. In one group both metals are fully reduced, in the other group one element is left as a positive ion; it can act as a chemical anchor'', or as a catalyst promoter for the reduced metal. The objective is to explore the potential of such materials for designing superior catalysts for synthesis and conversion of hydrocarbons and other energy carriers. ENDOR, EXAFS, CO-FTIR and TPD will be used to identify the interaction of Mn[sup 2+] ions with Rh[sub n] particles in the same zeolite cage. EXAFS at the Kedge of Fe and Pd, FTIR and Moessbauer spectroscopy will be used to characterize Fe ions and alloyed Fe atoms in PdFe/NaHY. The catalysts will be probed with CO hydrogenation and conversion of hydrocarbons. Methods Which proved successful in our study of Y supported bimetal systems will be applied to identify the state of Pt and Cu in ZSM-5, a catalyst system holding large promise for NO abatement, even in the presence of oxygen.

  10. Thermal decomposition of supported lithium nitrate catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz, Maria Lucia [INTEQUI (CONICET-UNSL), 25 de Mayo 384, V. Mercedes, 5730, San Luis (Argentina); Lick, Ileana Daniela [CINDECA (CONICET-UNLP), Calle 47 No 257, La Plata, 1900, Buenos Aires (Argentina); Ponzi, Marta Isabel [INTEQUI (CONICET-UNSL), 25 de Mayo 384, V. Mercedes, 5730, San Luis (Argentina); Castellon, Enrique Rodriguez; Jimenez-Lopez, Antonio [Departamento de Quimica Inorganica, Cristalografia y Mineralogia. Facultad de Ciencias, Universidad de Malaga, Campus de Teatinos, 29071 Malaga (Spain); Ponzi, Esther Natalia, E-mail: eponzi@quimica.unlp.edu.ar [CINDECA (CONICET-UNLP), Calle 47 No 257, La Plata, 1900, Buenos Aires (Argentina)

    2010-02-20

    New catalysts for soot combustion were prepared by impregnation of different supports (SiO{sub 2}, ZrO{sub 2} and ZrO{sub 2}.nH{sub 2}O) with a LiNO{sub 3} solution and then characterized by means of FTIR, XPS, TGA and UV-vis spectroscopy, whereby the presence of lithium nitrate in the prepared catalysts was identified and quantified. The soot combustion rate using this series of catalysts (LiNO{sub 3}/support) was compared with the activity of a series of impregnated catalysts prepared using LiOH (Li{sub 2}O/supports). Catalysts prepared using LiNO{sub 3} are found to be more active than those prepared using LiOH. The catalytic performance was also studied with a NO/O{sub 2} mixture in the feed, demonstrating that NO increases the combustion rate of soot, probably as a consequence of lithium oxide forming an 'in situ' nitrate ion.

  11. Protein Scaffolding for Small Molecule Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Baker, David [Univ. of Washington, Seattle, WA (United States)

    2014-09-14

    We aim to design hybrid catalysts for energy production and storage that combine the high specificity, affinity, and tunability of proteins with the potent chemical reactivities of small organometallic molecules. The widely used Rosetta and RosettaDesign methodologies will be extended to model novel protein / small molecule catalysts in which one or many small molecule active centers are supported and coordinated by protein scaffolding. The promise of such hybrid molecular systems will be demonstrated with the nickel-phosphine hydrogenase of DuBois et. al.We will enhance the hydrogenase activity of the catalyst by designing protein scaffolds that incorporate proton relays and systematically modulate the local environment of the catalyticcenter. In collaboration with DuBois and Shaw, the designs will be experimentally synthesized and characterized.

  12. Polypropylene obtained through zeolite supported catalysts

    Directory of Open Access Journals (Sweden)

    Queli C. Bastos

    2004-01-01

    Full Text Available Propylene polymerizations were carried out with f2C(Flu(CpZrCl2 and SiMe2(Ind2ZrCl2 catalysts supported on silica, zeolite sodic mordenite (NaM and acid mordenite (HM. The polymerizations were performed at different temperatures and varying aluminium/zirconium molar ratios ([Al]/[Zr]. The effect of these reaction parameters on the catalyst activity was investigated using a proposed statistical experimental planning. In the case of f2C(Flu(CpZrCl2, SiO2 and NaM were used as support and the catalyst performance evaluated using toluene and pentane as polymerization solvent. The molecular weight, molecular weight distribution, melting point and crystallinity of the polymers were examined. The results indicate very high activities for the syndiospecific heterogeneous system. Also, the polymers obtained had superior Mw and stereoregularity.

  13. Pyrochlore catalysts for hydrocarbon fuel reforming

    Science.gov (United States)

    Berry, David A.; Shekhawat, Dushyant; Haynes, Daniel; Smith, Mark; Spivey, James J.

    2012-08-14

    A method of catalytically reforming a reactant gas mixture using a pyrochlore catalyst material comprised of one or more pyrochlores having the composition A2B2-y-zB'yB"zO7-.DELTA., where y>0 and z.gtoreq.0. Distribution of catalytically active metals throughout the structure at the B site creates an active and well dispersed metal locked into place in the crystal structure. This greatly reduces the metal sintering that typically occurs on supported catalysts used in reforming reactions, and reduces deactivation by sulfur and carbon. Further, oxygen mobility may also be enhanced by elemental exchange of promoters at sites in the pyrochlore. The pyrochlore catalyst material may be utilized in catalytic reforming reactions for the conversion of hydrocarbon fuels into synthesis gas (H2+CO) for fuel cells, among other uses.

  14. Heterogeneous Catalyst Deactivation and Regeneration: A Review

    Directory of Open Access Journals (Sweden)

    Morris D. Argyle

    2015-02-01

    Full Text Available Deactivation of heterogeneous catalysts is a ubiquitous problem that causes loss of catalytic rate with time. This review on deactivation and regeneration of heterogeneous catalysts classifies deactivation by type (chemical, thermal, and mechanical and by mechanism (poisoning, fouling, thermal degradation, vapor formation, vapor-solid and solid-solid reactions, and attrition/crushing. The key features and considerations for each of these deactivation types is reviewed in detail with reference to the latest literature reports in these areas. Two case studies on the deactivation mechanisms of catalysts used for cobalt Fischer-Tropsch and selective catalytic reduction are considered to provide additional depth in the topics of sintering, coking, poisoning, and fouling. Regeneration considerations and options are also briefly discussed for each deactivation mechanism.

  15. Photocatalytic Denitrogenation over Modiifed Waste FCC Catalyst

    Institute of Scientific and Technical Information of China (English)

    Zheng Liuping; Lin Mei; Huang Yingying; Yan Guiyang; Zheng Binquan; Li Ling

    2013-01-01

    The strontium modiifed waste FCC catalyst was prepared by magnetic stirring method and characterized by X-ray diffractometry (XRD), UV-Vis diffuse relfectance spectrometry (DRS), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). Meanwhile, its photocatalytic denitrogenation performance was evaluated in terms of its ability to degrade the N-containing simulation oil under visible light. A mixture of strontium nitrate solution (with a concentration of 0.5 mol/L) and waste FCC catalyst was calcined at 400℃for 5 h prior to taking part in the photocatalytic denitrogenation reaction. The test results showed that the photocatalytic degradation rate of pyridine contained in simulation oil in the presence of the strontium modiifed FCC catalyst could reach 92.0%under visible light irradiation for 2.5 h.

  16. Examining the surfaces in used platinum catalysts

    Directory of Open Access Journals (Sweden)

    Trumić B.

    2009-01-01

    Full Text Available For the purpose of finding more advanced platinum catalyst manufacturing technologies and achieving a higher degree of ammonia oxidation, metallographic characterization has been done on the surface of catalyst gauzes and catalyst gripper gauzes made from platinum and palladium alloys. For the examined samples of gauzes as well as the cross section of the wires, a chemical analysis was provided. The purpose of this paper is the metallographic characterization of examined alloys carried out by way of electronic microscopic scanning, X-rays as well as chemical assays which contributed greatly to a better understanding of the surface deactivation, in other words a better consideration of structural changes occurring on the wire surface.

  17. Homogeneous and heterogenized iridium water oxidation catalysts

    Science.gov (United States)

    Macchioni, Alceo

    2014-10-01

    The development of an efficient catalyst for the oxidative splitting of water into molecular oxygen, protons and electrons is of key importance for producing solar fuels through artificial photosynthesis. We are facing the problem by means of a rational approach aimed at understanding how catalytic performance may be optimized by the knowledge of the reaction mechanism of water oxidation and the fate of the catalytic site under the inevitably harsh oxidative conditions. For the purposes of our study we selected iridium water oxidation catalysts, exhibiting remarkable performance (TOF > 5 s-1 and TON > 20000). In particular, we recently focused our attention on [Cp*Ir(N,O)X] (N,O = 2-pyridincarboxylate; X = Cl or NO3) and [IrCl(Hedta)]Na water oxidation catalysts. The former exhibited a remarkable TOF whereas the latter showed a very high TON. Furthermore, [IrCl(Hedta)]Na was heterogenized onto TiO2 taking advantage of the presence of a dandling -COOH functionality. The heterogenized catalyst maintained approximately the same catalytic activity of the homogeneous analogous with the advantage that could be reused many times. Mechanistic studies were performed in order to shed some light on the rate-determining step and the transformation of catalysts when exposed to "oxidative stress". It was found that the last oxidative step, preceding oxygen liberation, is the rate-determining step when a small excess of sacrificial oxidant is used. In addition, several intermediates of the oxidative transformation of the catalyst were intercepted and characterized by NMR, X-Ray diffractometry and ESI-MS.

  18. Highly Durable Catalysts for Ignition of Advanced Monopropellants Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Monopropellants are readily ignited or decomposed over a bed of solid catalyst. A serious limitation of existing catalysts in the ignition of advanced...

  19. Method of performing sugar dehydration and catalyst treatment

    Science.gov (United States)

    Hu, Jianli [Kennewick, WA; Holladay, Johnathan E [Kennewick, WA; Zhang, Xinjie [Burlington, MA; Wang, Yong [Richland, WA

    2010-06-01

    The invention includes a method of treating a solid acid catalyst. After exposing the catalyst to a mixture containing a sugar alcohol, the catalyst is washed with an organic solvent and is then exposed to a second reaction mixture. The invention includes a process for production of anhydrosugar alcohol. A solid acid catalyst is provided to convert sugar alcohol in a first sample to an anhydrosugar alcohol. The catalyst is then washed with an organic solvent and is subsequently utilized to expose a second sample. The invention includes a method for selective production of an anhydrosugar. A solid acid catalyst is provided within a reactor and anhydrosugar alcohol is formed by flowing a starting sugar alcohol into the reactor. The acid catalyst is then exposed to an organic solvent which allows a greater amount of additional anhydrosugar to be produced than would occur without exposing the acid catalyst to the organic solvent.

  20. Mordenite - Type Zeolite SCR Catalysts with Iron or Copper

    DEFF Research Database (Denmark)

    2012-01-01

    Cu/mordenite catalysts were found to be highly active for the SCR of NO with NH3 and exhibited high resistance to alkali poisoning. Redox and acidic properties of Cu/mordenite were well preserved after poisoning with potassium unlike that of vanadium catalysts. Fe-mordenite catalysts also reveale...... to be essential requirements for the high alkali resistance. Mordenite-type zeolite based catalysts could therefore be attractive alternatives to conventional SCR catalysts for biomass fired power plant flue gas treatment.......Cu/mordenite catalysts were found to be highly active for the SCR of NO with NH3 and exhibited high resistance to alkali poisoning. Redox and acidic properties of Cu/mordenite were well preserved after poisoning with potassium unlike that of vanadium catalysts. Fe-mordenite catalysts also revealed...

  1. Dearomatization of jet fuel on irradiated platinum-supported catalyst

    Science.gov (United States)

    Múčka, V.; Ostrihoňová, A.; Kopernický, I.; Mikula, O.

    The effect of ionizing radiation ( 60Co γ-rays) on Pt-supported catalyst used for the dearomatization of jet fuel with distillation in the range 395-534 K has been studied. Pre-irradiation of the catalyst with doses in the range 10 2-5 × 10 4 Gy leads to the partial catalyst activation. Irradiation of the catalyst enhances its resistance to catalyst poisons, particularly to sulphur-compounds, and this is probably the reason for its catalytic activity being ˜60-100% greater than that of un-irradiated catalyst. Optimum conditions for dearomatization on the irradiated catalyst were found and, by means of a rotary three-factorial experiment, it was shown that these lie at lower temperatures and lower pressures than those for un-irradiated catalyst.

  2. Advanced Aqueous Phase Catalyst Development using Combinatorial Methods Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The use of combinatorial methods is proposed to rapidly screen catalyst formulations for the advanced development of aqueous phase oxidation catalysts with greater...

  3. Enhancement of alkylation catalysts for improved supercritical fluid regeneration

    Science.gov (United States)

    Ginosar, Daniel M.; Petkovic, Lucia

    2009-09-22

    A method of modifying an alkylation catalyst to reduce the formation of condensed hydrocarbon species thereon. The method comprises providing an alkylation catalyst comprising a plurality of active sites. The plurality of active sites on the alkylation catalyst may include a plurality of weakly acidic active sites, intermediate acidity active sites, and strongly acidic active sites. A base is adsorbed to a portion of the plurality of active sites, such as the strongly acidic active sites, selectively poisoning the strongly acidic active sites. A method of modifying the alkylation catalyst by providing an alkylation catalyst comprising a pore size distribution that sterically constrains formation of the condensed hydrocarbon species on the alkylation catalyst or by synthesizing the alkylation catalyst to comprise a decreased number of strongly acidic active sites is also disclosed, as is a method of improving a regeneration efficiency of the alkylation catalyst.

  4. Asymmetric synthesis of polypiperylene on a lanthanide-containing catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Monakov, Yu.B.; Marina, N.G.; Kozlova, O.I.; Kanzafarov, F.Ya.; Tolstikov, G.A.

    1987-07-01

    The authors study the polymerization of piperylene and subsequent synthesis of polypiperylene on a neodymium chloride catalyst containing a sulfoxide and an aluminium complex. Specifics of the catalyst preparation and activity are given.

  5. Application of Ion Beam Processing Technology in Production of Catalysts

    Directory of Open Access Journals (Sweden)

    Mykola G. Bannikov, Javed A. Chattha

    2012-08-01

    Full Text Available In this paper, the applicability of Ion Beam Processing Technology for making catalysts has been inves-tigated. Ceramic substrates of different shapes and metal fibre tablets were implanted by platinum ions and tested in nitrogen oxides (NOx and carbon monoxide (CO conversion reactions. Effectiveness of the implanted catalysts was compared to that of the commercially produced platinum catalysts made by impregnation. Platinum-implanted catalyst having fifteen times less platinum content showed the same CO conversion efficiency as the commercially pro-duced catalyst. It was revealed that the effectiveness of the platinum-implanted catalyst has complex dependence on the process parameters and the optimum can be achieved by varying the ions energy and the duration of implantation. Investigation of the pore structure showed that ion implantation did not decrease the specific surface area of the catalyst.Key Words: Catalyst, Ion Implantation, Noble metals.

  6. Resin catalysts and method of preparation

    Science.gov (United States)

    Smith, L.A. Jr.

    1986-12-16

    Heat stabilized catalyst compositions are prepared from nuclear sulfonic acid, for example, macroporous crosslinked polyvinyl aromatic compounds containing sulfonic acid groups are neutralized with a metal of Al, Fe, Zn, Cu, Ni, ions or mixtures and alkali, alkaline earth metals or ammonium ions by contacting the resin containing the sulfonic acid with aqueous solutions of the metals salts and alkali, alkaline earth metal or ammonium salts. The catalysts have at least 50% of the sulfonic acid groups neutralized with metal ions and the balance of the sulfonic acid groups neutralized with alkali, alkaline earth ions or ammonium ions.

  7. Catalysis by nonmetals rules for catalyst selection

    CERN Document Server

    Krylov, Oleg V

    1970-01-01

    Catalysis by Non-metals: Rules of Catalyst Selection presents the development of scientific principles for the collection of catalysts. It discusses the investigation of the mechanism of chemosorption and catalysis. It addresses a series of properties of solid with catalytic activity. Some of the topics covered in the book are the properties of a solid and catalytic activity in oxidation-reduction reactions; the difference of electronegativities and the effective charges of atoms; the role of d-electrons in the catalytic properties of a solid; the color of solids; and proton-acid and proton-ba

  8. Crotonaldehyde hydrogenation on Rh supported catalysts

    OpenAIRE

    Reyes, P; Aguirre, Mª del Carmen; Pecchi, Gina; García Fierro, José Luis

    2000-01-01

    The vapor-phase hydrogenation of crotonaldehyde on Rh supported catalysts has been studied. The effect of some variables of preparation in catalysts prepared by the sol-gel and impregnation methods on the surface and catalytic properties were analyzed. It was found, that the porosity of the support has a small effect on the selectivity to the unsaturated alcohol and the presence of partially reducible supports such as ZrO2 and TiO2, may increase the selectivity to crotyl alcohol via an enhanc...

  9. Ruthenium-Aryloxide Catalysts for Olefin Metathesis

    Science.gov (United States)

    Monfette, Sebastien; Blacquiere, Johanna M.; Conrad, Jay C.; Beach, Nicholas J.; Fogg, Deryn E.

    : Advances in design of ruthenium aryloxide catalysts for olefin metathesis are described. The target complexes are accessible on reaction of RuCl2(NHC)(py)2 (CHPh) (NHC - N-heterocyclic carbene) with electron-deficient, monodentate aryl- oxides, or aryloxides that yield small, rigid chelate rings. The best of these catalysts offer activity comparable to or greater than that of the parent chloride (Grubbs) systems in ring-closing metathesis (RCM). Preliminary studies of the electronic nature of the Ru-X bond suggest that the metal center is more electropositive in the aryloxide complexes than in the Grubbs systems.

  10. Sintering of nickel steam reforming catalysts

    DEFF Research Database (Denmark)

    Sehested, Jens; Larsen, Niels Wessel; Falsig, Hanne;

    2014-01-01

    . In this paper, particle migration and coalescence in nickel steam reforming catalysts is studied. Density functional theory calculations indicate that Ni-OH dominate nickel transport at nickel surfaces in the presence of steam and hydrogen as Ni-OH has the lowest combined energies of formation and diffusion...... compared to other potential nickel transport species. The relation between experimental catalyst sintering data and the effective mass diffusion constant for Ni-OH is established by numerical modelling of the particle migration and coalescence process. Using this relation, the effective mass diffusion...

  11. Preliminary toxicological study of Silastic 386 catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Smith, D.M.; Drake, G.A.; Holland, L.M.; Jackson, D.E.; London, J.E.; Prine, J.R.; Thomas, R.G.

    1978-06-01

    The calculated acute oral LD/sub 50//sup 30/ values for Silastic 386 catalyst were 1225 mg/kg in mice and 4350 mg/kg in rats. According to classical guidelines, the compound would be slightly to moderately toxic in both species. Skin application studies in the rabbit demonstrated the compound to be mildly irritating. The eye irritation study disclosed the compound to be a severe irritant causing conjunctivitis, photophobia, corneal edema, corneal ulceration, anterior uveitis, and keratitis. The sensitization study in the guinea pig did not show Silastic 386 catalyst to be deleterious in this regard.

  12. Ruthenium-based olefin metathesis catalysts bearing pH-responsive ligands: External control of catalyst solubility and activity

    Science.gov (United States)

    Balof, Shawna Lynn

    2011-12-01

    Sixteen novel, Ru-based olefin metathesis catalysts bearing pH responsive ligands were synthesized. The pH-responsive groups employed with these catalysts included dimethylamino (NMe2) modified NHC ligands as well as N-donor dimethylaminopyridine (DMAP) and 3-(o-pyridyl)propylidene ligands. These pH-responsive ligands provided the means by which the solubility and/or activity profiles of the catalysts produced could be controlled via acid addition. The main goal of this dissertation was to design catalyst systems capable of performing ring opening metathesis (ROMP) and ring closing metathesis (RCM) reactions in both organic and aqueous media. In an effort to quickly gain access to new catalyst structures, a template synthesis for functionalized NHC ligand precursors was designed, in addition to other strategies, to obtain ligand precursors with ancillary NMe2 groups. Kinetic studies for the catalysts produced from these precursors showed external control of catalyst solubility was afforded via protonation of the NMe2 groups of their NHC ligands. Additionally, this protonation afforded external control of catalyst propagation rates for several catalysts. This is the first known independent external control for the propagation rates of ROMP catalysts. The incorporation of pH-responsive N-donor ligands into catalyst structures also provided the means for the external control of metathesis activity, as the protonation of these ligands resulted in an increased initiation rate based on their fast and irreversible dissociation from the metal center. The enhanced external control makes these catalysts applicable to a wide range of applications, some of which have been explored by us and/or through collaboration. Three of the catalysts designed showed remarkable metathesis activity in aqueous media. These catalysts displayed comparable RCM activity in aqueous media to a class of water-soluble catalysts reported by Grubbs et al., considered to be the most active catalyst for

  13. Deactivation of platinum catalysts by oxygen 2. Nature of the catalyst deactivation

    Energy Technology Data Exchange (ETDEWEB)

    Dijkgraaf, P.J.M.; Duisters, H.A.M.; Kuster, B.F.M.; van der Wiele, K. (Univ. of Technology, Eindhoven (Netherlands))

    1988-08-01

    The effect of different start-up procedures on the deactivation of a 5% Pt/C catalyst used for the oxidation of D-gluconate has been investigated. Results have been obtained both in a stirred tank reactor for batch experiments and in an apparatus for continuous oxidation processes. The deactivation of the catalyst is not explicable by formation of platinum oxides. A model is proposed for the deactivation of platinum catalysts by oxygen, based on penetration of oxygen atoms into the platinum lattice.

  14. Sulfur Tolerance of CeO2 Promoted Pd/Al2O3 Catalyst on Hydrodesulfurization Reaction%CeO2改性的Pd/Al2O3催化剂在加氢脱硫反应中的抗硫性能

    Institute of Scientific and Technical Information of China (English)

    鲁勋; 罗来涛; 程新孙

    2008-01-01

    采用浸渍法制备CeO2改性的Pd/Al2O3催化剂,以噻吩加氢脱硫为探针反应,考察了Pd/Al2O3 和Pd-CeO2/Al2O3催化剂的活性和抗硫性能,并运用CO吸附、FT-IR、TG等分析测试技术研究表征了催化剂性质. 结果表明,Pd-CeO2/Al2O3催化剂比Pd /Al2O3催化剂具有较低的硫化度. 在连续反应中,Pd-CeO2/Al2O3催化剂的抗硫失活能力较强. CeO2的加入导致了Pd-S键能的减弱,在Pd-CeO2/Al2O3催化剂上H2S主要吸附在CeO2上而不是Pd原子上. Pd-CeO2/Al2O3抗硫能力的提高是由于Pd-Ce结合导致Pd缺电子状态,减少了Pd的硫化失活而引起. CeO2对H2S的竞争吸附造成与CeO2结合作用的Pd处于较低的H2S分压,减少了Pd失活的几率.

  15. 溶胶-凝胶法制备体相型Mo-Ni复合氧化物催化剂及其加氢脱硫性能研究%SYNTHESIS OF Mo-Ni BULK CATALYST BY SOL-GEL METHOD AND ITS HYDRODESULFURIZATION PERFORMANCE

    Institute of Scientific and Technical Information of China (English)

    张大龙; 徐永卫; 李孟华; 侯凯湖

    2016-01-01

    采用溶胶-凝胶法制备了体相型Mo-Ni复合氧化物加氢脱硫催化剂,并对其进行XRD,BET,NH3-TPD等表征,以二苯并噻吩质量分数2%的正辛烷溶液为原料,在连续固定床反应装置上对催化剂的加氢脱硫性能进行评价,考察催化剂焙烧温度、溶胶凝胶过程中溶液pH以及淀粉的加入量等对催化剂性质和性能的影响.结果表明:在500℃以上高温焙烧后的氧化态催化剂中主要存在α-NiMoO4和β-NiMoO4晶相,硫化态催化剂中则存在MoS2和Ni2S3晶相;焙烧温度的升高有利于氧化态催化剂形成α-NiMoO4晶相,溶液碱性的增加则有利于形成β-NiMoO4晶相,二者均导致催化剂的总酸量显著降低;淀粉的加入对氧化态催化剂的晶相影响很小,但有利于提高活性组分的分散性,适量淀粉的加入可提高催化剂的比表面积和孔体积;在焙烧温度为600℃、溶液pH为2和淀粉加入量为15 g/mol的条件下所制备的催化剂具有较高的加氢脱硫活性,在反应温度为260℃、反应压力为2.5 MPa、体积空速为2h-1和氢油体积比为300的条件下,对于硫质量分数为3 480μg/g的原料,加氢脱硫率高达98.3%,二苯并噻吩的反应以加氢脱硫路径占优势,加氢脱硫路径与氢解脱硫路径反应的比值约为1.23.

  16. Thief carbon catalyst for oxidation of mercury in effluent stream

    Science.gov (United States)

    Granite, Evan J.; Pennline, Henry W.

    2011-12-06

    A catalyst for the oxidation of heavy metal contaminants, especially mercury (Hg), in an effluent stream is presented. The catalyst facilitates removal of mercury through the oxidation of elemental Hg into mercury (II) moieties. The active component of the catalyst is partially combusted coal, or "Thief" carbon, which can be pre-treated with a halogen. An untreated Thief carbon catalyst can be self-promoting in the presence of an effluent gas streams entrained with a halogen.

  17. Palladium–tin catalysts on conducting polymers for nitrate removal

    OpenAIRE

    Dodouche, Ibrahim; Barbosa, Danns Pereira; Varela, Maria do Carmo Rangel Santos; Epron, Florence

    2009-01-01

    Trabalho completo: acesso restrito, p. 50–55 Palladium–tin catalysts were prepared by successive impregnation or co-impregnation onto polyaniline and polypyrrole. The catalytic tests showed that this type of catalyst is active for nitrate reduction. The use of polymer support improves the selectivity of the catalyst toward nitrogen formation compared to a classical support, and avoids the apparition of intermediate nitrite. These better performances of the catalysts supported on electroact...

  18. Catalyst deactivation. Is it predictable? What to do?

    Energy Technology Data Exchange (ETDEWEB)

    Moulijn, J.A.; Van Diepen, A.E.; Kapteijn, F. [Department of Chemical Process Technology, Section of Industrial Catalysis, Faculty of Applied Sciences, Delft University of Technology, Julianalaan 136, 2628 BL Delft (Netherlands)

    2001-04-30

    Catalyst deactivation is usually inevitable, although the rate at which it occurs varies greatly. This article discusses the causes of deactivation and the influence on reaction rate. Methods for minimising catalyst deactivation, by tailoring catalyst properties and/or process operations, are presented, as well as reactor configurations suitable for the regeneration of deactivated catalysts. Alkane dehydrogenation is used as an example to demonstrate the variety of engineering solutions possible.

  19. Tethered catalysts for the hydration of carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Valdez, Carlos A; Satcher, Jr., Joe H; Aines, Roger D; Wong, Sergio E; Baker, Sarah E; Lightstone, Felice C; Stolaroff, Joshuah K

    2014-11-04

    A system is provided that substantially increases the efficiency of CO.sub.2 capture and removal by positioning a catalyst within an optimal distance from the air-liquid interface. The catalyst is positioned within the layer determined to be the highest concentration of carbon dioxide. A hydrophobic tether is attached to the catalyst and the hydrophobic tether modulates the position of the catalyst within the liquid layer containing the highest concentration of carbon dioxide.

  20. Fries Rearrangement of Phenyl Acetate over Solid Acid Catalyst

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A silica-supported zirconium based solid acid (ZS) has been used as catalyst for the Fries rearrangement of phenyl acetate (PA). The catalyst showed a higher PA conversion activity and a much higher selectivity for o-hydroxyacetophenone (o-HAP) than for strongly acidic zeolite catalysts. The supported catalyst was characterized by XRD, IR, XPS, pyridine-TPD and the surface area measurements. The catalytic properties were influenced significantly by pretreatment temperature.

  1. Fries Rearrangement of Phenyl Acetate over Solid Acid Catalyst

    Institute of Scientific and Technical Information of China (English)

    CanXiongGUO; YanLIU; 等

    2002-01-01

    A silica-supported zirconium based solid acid (ZS) has been used as catalyst for the Fries rearrangement of phenyl acetate (PA). The catalyst showed a higher PA conversion activity and a much higher selectivity for o-hydroxyacetophenone (o-HAP) than for strongly acidic zeolite catalysts. The supported catalyst was characterized by XRD,IR,XPS,pyridine-TPD and the surface area measurements. The catalytic properties were influenced significantly by pretreatment temperature.

  2. Nano Catalysts for Diesel Engine Emission Remediation

    Energy Technology Data Exchange (ETDEWEB)

    Narula, Chaitanya Kumar [ORNL; Yang, Xiaofan [ORNL; Debusk, Melanie Moses [ORNL; Mullins, David R [ORNL; Mahurin, Shannon Mark [ORNL; Wu, Zili [ORNL

    2012-06-01

    The objective of this project was to develop durable zeolite nanocatalysts with broader operating temperature windows to treat diesel engine emissions to enable diesel engine based equipment and vehicles to meet future regulatory requirements. A second objective was to improve hydrothermal durability of zeolite catalysts to at least 675 C. The results presented in this report show that we have successfully achieved both objectives. Since it is accepted that the first step in NO{sub x} conversion under SCR (selective catalytic reduction) conditions involves NO oxidation to NO{sub 2}, we reasoned that catalyst modification that can enhance NO oxidation at low-temperatures should facilitate NO{sub x} reduction at low temperatures. Considering that Cu-ZSM-5 is a more efficient catalyst than Fe-ZSM-5 at low-temperature, we chose to modify Cu-ZSM-5. It is important to point out that the poor low-temperature efficiency of Fe-ZSM-5 has been shown to be due to selective absorption of NH{sub 3} at low-temperatures rather than poor NO oxidation activity. In view of this, we also reasoned that an increased electron density on copper in Cu-ZSM-5 would inhibit any bonding with NH{sub 3} at low-temperatures. In addition to modified Cu-ZSM-5, we synthesized a series of new heterobimetallic zeolites, by incorporating a secondary metal cation M (Sc{sup 3+}, Fe{sup 3+}, In{sup 3+}, and La{sup 3+}) in Cu exchanged ZSM-5, zeolite-beta, and SSZ-13 zeolites under carefully controlled experimental conditions. Characterization by diffuse-reflectance ultra-violet-visible spectroscopy (UV-Vis), X-ray powder diffraction (XRD), extended X-ray absorption fine structure spectroscopy (EXAFS) and electron paramagnetic resonance spectroscopy (EPR) does not permit conclusive structural determination but supports the proposal that M{sup 3+} has been incorporated in the vicinity of Cu(II). The protocols for degreening catalysts, testing under various operating conditions, and accelerated aging

  3. Biomass Conversion over Heteropoly Acid Catalysts

    KAUST Repository

    Zhang, Jizhe

    2015-04-01

    Biomass is a natural resource that is both abundant and sustainable. Its efficient utilization has long been the focus of research and development efforts with the aim to substitute it for fossil-based feedstock. In addition to the production of biofuels (e.g., ethanol) from biomass, which has been to some degree successful, its conversion to high value-added chemicals is equally important. Among various biomass conversion pathways, catalytic conversion is usually preferred, as it provides a cost-effective and eco-benign route to the desired products with high selectivities. The research of this thesis is focused on the conversion of biomass to various chemicals of commercial interest by selective catalytic oxidation. Molecular oxygen is chosen as the oxidant considering its low cost and environment friendly features in comparison with commonly used hydrogen peroxide. However, the activation of molecular oxygen usually requires high reaction temperatures, leading to over oxidation and thus lower selectivities. Therefore, it is highly desirable to develop effective catalysts for such conversion systems. We use kegging-type heteropoly acids (HPAs) as a platform for catalysts design because of their high catalytic activities and ease of medication. Using HPA catalysts allows the conversion taking place at relatively low temperature, which is beneficial to saving production cost as well as to improving the reaction selectivity. The strong acidity of HPA promotes the hydrolysis of biomass of giant molecules (e.g. cellulose), which is the first as well as the most difficult step in the conversion process. Under certain circumstances, a HPA combines the merits of homogeneous and heterogeneous catalysts, acting as an efficient homogeneous catalyst during the reaction while being easily separated as a heterogeneous catalyst after the reaction. We have successfully applied HPAs in several biomass conversion systems. Specially, we prepared a HPA-based bi-functional catalyst

  4. 40 CFR 91.427 - Catalyst thermal stress resistance evaluation.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Catalyst thermal stress resistance... Procedures § 91.427 Catalyst thermal stress resistance evaluation. (a)(1) The purpose of the evaluation procedure specified in this section is to determine the effect of thermal stress on catalyst...

  5. Enhanced gasification of wood in the presence of mixed catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Weber, S. L.; Mudge, L. K.; Sealock, Jr., L. J.; Robertus, R. J.; Mitchell, D. E.

    Experimental results obtained in laboratory investigations of steam gasification of wood in the presence of mixed catalysts are presented. These studies are designed to test the technical feasibility of producing specific gaseous products from wood by enhancing its reactivity and product specificity through the use of combined catalysts. The desired products include substitute natural gas, hydrocarbon synthesis gas and ammonia synthesis gas. The gasification reactions are controlled through the use of specific catalyst combinations and operating parameters. A primary alkali carbonate gasification catalyst impregnated into the wood combined with specific commercially available secondary catalysts produced the desired products. A yield of 50 vol % methane was obtained with a randomly mixed combination of a commercial nickel methanation catalyst and silica-alumina cracking catalyst at a weight ratio of 3:1 respectively. Steam gasification of wood in the presence of a commercial Si-Al cracking catalyst produced the desired hydrocarbon synthesis gas. Hydrogen-to-carbon monoxide ratios needed for Fischer-Tropsch synthesis of hydrocarbons were obtained with this catalyst system. A hydrogen-to-nitrogen ratio of 3:1 for ammonia synthesis gas was achieved with steam-air gasification of wood in the presence of catalysts. The most effective secondary catalyst system employed to produce the ammonia synthesis gas included two commercially prepared catalysts formulated to promote the water-gas shift reaction.

  6. Moessbauer study of function of magnesium in iron oxide catalysts

    Institute of Scientific and Technical Information of China (English)

    YangJie-Xin; MaoLian-Sheng; 等

    1997-01-01

    Moessbauer spectroscopy has been utilized for studying the action of Mg element in iron oxide catalysts used for the dehydrogenation of ethylbenzene to sytrene.The experimental results show that the presence of opportune amount of Mg can enhance the stability and dispersion of catalysts,i.e.Mg is an sueful structure promoter in this kind of catalysts.

  7. Methanol Steam Reforming Catalysts for Fuel Cell Driven Electric Vehicles

    Institute of Scientific and Technical Information of China (English)

    Yongfeng Li; Xinfa Dong; Weiming Lin

    2003-01-01

    Cu/ZnAlO catalysts derived from hydroxycarbonate precursors containing hydrotalcite-likelayered double hydroxides (LDHs) were studied. The influence on the performance of the catalysts wasalso studied when the Al in the Cu/ZnAlO catalyst was partly or completely replaced by Zr or Ce.

  8. The Immobilization of a Transfer Hydrogenation Catalyst on Colloidal Particles

    NARCIS (Netherlands)

    van Ravensteijn, Bas G P; Schild, Dirk Jan; Kegel, Willem K.; Klein Gebbink, Robertus J M

    2017-01-01

    In this paper, we report a new synthetic procedure to immobilize a transfer hydrogenation catalyst on the surface of colloidal polystyrene particles. Using supports of colloidal dimensions allows for combining a relatively high surface area for catalyst binding, mobility of the catalyst, and facile

  9. Hydrogenation of cottonseed oil with nickel, palladium and platinum catalysts

    Science.gov (United States)

    A number of commercial catalysts have been used to study hydrogenation of cottonseed oil, with the goal of minimizing trans fatty acid (TFA) content. Despite the different temperatures used, catalyst levels, and reaction times, the data from each catalyst type fall on the same curve when the TFA le...

  10. Monte Carlo simulation of the PEMFC catalyst layer

    Institute of Scientific and Technical Information of China (English)

    WANG Hongxing; CAO Pengzhen; WANG Yuxin

    2007-01-01

    The performance of the polymer electrolyte membrane fuel cell (PEMFC) is greatly controlled by the structure of the catalyst layer.Low catalyst utilization is still a significant obstacle to the commercialization of the PEMFC.In order to get a fundamental understanding of the electrode structure and to find the limiting factor in the low catalyst utilization,it is necessary to develop the mechanical model on the effect of catalyst layer structure on the catalyst utilization and the performance of the PEMFC.In this work,the structure of the catalyst layer is studied based on the lattice model with the Monte Carlo simulation.The model can predict the effects of some catalyst layer components,such as Pt/C catalyst,electrolyte and gas pores,on the utilization of the catalyst and the cell performance.The simulation result shows that the aggregation of conduction grains can greatly affect the degree of catalyst utilization.The better the dispersion of the conduction grains,the larger the total effective area of the catalyst is.To achieve higher utilization,catalyst layer components must be distributed by means of engineered design,which can prevent aggregation.

  11. A One-Bead-One-Catalyst Approach to Aspartic Acid-Based Oxidation Catalyst Discovery

    Science.gov (United States)

    Lichtor, Phillip A.; Miller, Scott J.

    2011-01-01

    We report an approach to the high-throughput screening of asymmetric oxidation catalysts. The strategy is based on application of the one-bead-one-compound library approach, wherein each of our catalyst candidates is based on a peptide scaffold. For this purpose we rely on a recently developed catalytic cycle that employs an acid-peracid shuttle. In order to implement our approach, we developed a compatible linker and demonstrated that the library format is amenable to screening and sequencing of catalysts employing partial Edman degradation and MALDI mass spectrometry analysis. The system was applied to the discovery (and re-discovery) of catalysts for the enantioselective oxidation of a cyclohexene derivative. The system is now poised for application to unprecedented substrate classes for asymmetric oxidation reactions. PMID:21417485

  12. Covalent anchoring of a racemization catalyst to CALB-beads: towards dual immobilization of DKR catalysts

    NARCIS (Netherlands)

    Wieczorek, B.; Träff, A.; Krumlinde, P.; Dijkstra, H.P.; Egmond, M.R.; van Koten, G.; Bäckvall, J.-E.; Klein Gebbink, R.J.M.

    2011-01-01

    The preparation of a heterogeneous bifunctional catalytic system, combining the catalytic properties of an organometallic catalyst (racemization) with those of an enzyme (enantioselective acylation) is described. A novel ruthenium phosphonate inhibitor was synthesized and covalently anchored to a

  13. Conversion of dimethyl ether on zeolite catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Abramova, A.V.; Kulumbegov, R.V.; Khadzhiev, S.N. [Russian Academy of Sciences, Moscow (Russian Federation). A.V. Topchiev Inst. of Petrochemical Synthesis

    2006-07-01

    Catalytic conversion of dimethyl ether to hydrocarbons was investigated using zeolite catalyst ZSM-5 type. 2% MexOy - 60% HZVM(analogue of ZSM-5)/Al{sub 2}O{sub 3}, (Me = Zn, Ga, Fe, Co, V, Ni) catalyst samples have been obtained. The reaction was carried out in a fixed bed reaction set-up at 350-400 C, pressure 3 MPa, gas mix (% vol.): 24 DME, 76 N{sub 2}, WHSV=1300 l/l-{sub kat.}h. Most effective catalysts of DME conversion are pentasil based catalysts with promoter metals zinc, iron and cobalt by totality DME-conversion, gas and liquid hydrocarbon selectivity, ethylene and propylene content in gas. The best work temperatures are 350 and 375 C, thereupon increasing of temperature to 400 C leads to considerable growth of methane in hydrocarbon gas. Liquid hydrocarbons have high content of aromatics and iso-paraffins. Liquid hydrocarbon product is characterized by high octane number (RON) 90-98. (orig.)

  14. Nitrated metalloporphyrins as catalysts for alkane oxidation

    Science.gov (United States)

    Ellis, Jr., Paul E.; Lyons, James E.

    1992-01-01

    Alkanes are oxidized by contact with oxygen-containing gas in the presence as catalyst of a metalloporphyrin in which hydrogen atoms in the porphyrin ring have been replaced with one or more nitro groups. Hydrogen atoms in the porphyrin ring may also be substituted with halogen atoms.

  15. Hydrodeoxygenation of Levulinic Acid over Supported Catalysts

    NARCIS (Netherlands)

    Luo, Wenhao

    2014-01-01

    Levulinic acid (LA), which can be produced from the sugar fractions of lignocellulosic biomass, is a promising sustainable platform molecule that can play a major role in future biorefineries. The work described was aimed at the development of heterogeneous catalysts for the selective conversion of

  16. Catalyst system of the structured type

    NARCIS (Netherlands)

    Jansen, J.C.; Legein, C.H.; Calis, H.P.A.; Van Bekkum, H.; Gerritsen, A.W.; Van den Bleek, M.

    1994-01-01

    The invention relates to a catalyst system of the structured type, in which a structured support is covered with a layer of molecular sieve crystals and/or modifications thereof. These crystals have substantially the same orientation relative to the support surface. The invention further relates to

  17. Catalyst Activity Comparison of Alcohols over Zeolites

    Energy Technology Data Exchange (ETDEWEB)

    Ramasamy, Karthikeyan K.; Wang, Yong

    2013-01-01

    Alcohol transformation to transportation fuel range hydrocarbon on HZSM-5 (SiO2 / Al2O3 = 30) catalyst was studied at 360oC and 300psig. Product distributions and catalyst life were compared using methanol, ethanol, 1-propanol or 1-butanol as a feed. The catalyst life for 1-propanol and 1-butanol was more than double compared to that for methanol and ethanol. For all the alcohols studied, the product distributions (classified to paraffin, olefin, napthene, aromatic and naphthalene compounds) varied with time on stream (TOS). At 24 hours TOS, liquid product from 1-propanol and 1-butanol transformation primarily contains higher olefin compounds. The alcohol transformation process to higher hydrocarbon involves a complex set of reaction pathways such as dehydration, oligomerization, dehydrocyclization, and hydrogenation. Compared to ethylene generated from methanol and ethanol, oligomerization of propylene and butylene has a lower activation energy and can readily take place on weaker acidic sites. On the other hand, dehydrocyclization of propylene and butylene to form the cyclic compounds requires the sits with stronger acid strength. Combination of the above mentioned reasons are the primary reasons for olefin rich product generated in the later stage of the time on stream and for the extended catalyst life time for 1 propanol and 1 butanol compared to methanol and ethanol conversion over HZSM-5.

  18. Pt/C Fuel Cell Catalyst Degradation

    DEFF Research Database (Denmark)

    Zana, Alessandro

    This thesis investigates the degradation behavior of Pt/C catalysts under simulated automotive conditions. By using the “tool box” synthesis method the Pt loading has been changed from low to high Pt loadings, therefore permitting to study the role of Pt on the degradation of high surface area (H...

  19. Theoretical Studies of Homogeneous Catalysts Mimicking Nitrogenase

    Directory of Open Access Journals (Sweden)

    Alessandra Magistrato

    2011-01-01

    Full Text Available The conversion of molecular nitrogen to ammonia is a key biological and chemical process and represents one of the most challenging topics in chemistry and biology. In Nature the Mo-containing nitrogenase enzymes perform nitrogen ‘fixation’ via an iron molybdenum cofactor (FeMo-co under ambient conditions. In contrast, industrially, the Haber-Bosch process reduces molecular nitrogen and hydrogen to ammonia with a heterogeneous iron catalyst under drastic conditions of temperature and pressure. This process accounts for the production of millions of tons of nitrogen compounds used for agricultural and industrial purposes, but the high temperature and pressure required result in a large energy loss, leading to several economic and environmental issues. During the last 40 years many attempts have been made to synthesize simple homogeneous catalysts that can activate dinitrogen under the same mild conditions of the nitrogenase enzymes. Several compounds, almost all containing transition metals, have been shown to bind and activate N2 to various degrees. However, to date Mo(N2(HIPTN3N with (HIPTN3N= hexaisopropyl-terphenyl-triamidoamine is the only compound performing this process catalytically. In this review we describe how Density Functional Theory calculations have been of help in elucidating the reaction mechanisms of the inorganic compounds that activate or fix N2. These studies provided important insights that rationalize and complement the experimental findings about the reaction mechanisms of known catalysts, predicting the reactivity of new potential catalysts and helping in tailoring new efficient catalytic compounds.

  20. Improving performance of catalysts for water electrolysis

    DEFF Research Database (Denmark)

    Frydendal, Rasmus

    This Ph.D. thesis presents work on non-noble metal oxide catalysts for the oxygen evolution reaction, OER. This reaction is currently a bottleneck in electrolyzer technologies, which are promising for energy storage purposes. In particular, Polymer Electrolyte Membrane, PEM, cells are attractive ...

  1. Overview of Support Effects in Hydrotreating Catalysts

    Institute of Scientific and Technical Information of China (English)

    Michèle Breysse

    2004-01-01

    @@ Industrial hydrotreating (HDT) catalysts are composed of a molybdenum sulfide (or tungsten sulfide) phase promoted by cobalt or nickel and usually supported on alumina. The origin of the almost exclu1sive use of alumina as support has to be ascribed to its outstanding textural and mechanical properties and its relatively low cost[1].

  2. SOME PRELIMINARY INFORMATION ON SYNDIOTACTIC POLYSTYRENE CATALYSTS

    Institute of Scientific and Technical Information of China (English)

    Adolfo Zambelli; Claudio Pellecchia; Leone Oliva; HAN Shimin

    1988-01-01

    Syndiotactic specific polymerization of styrene has been investigated by 13C NMR analysis and isotopic labelling methods. The value of the activation energy involved in the sterie control has been determined. Some information of the number of the active sites and on the life of the catalysts is reported.

  3. Pt/C Fuel Cell Catalyst Degradation

    DEFF Research Database (Denmark)

    Zana, Alessandro

    This thesis investigates the degradation behavior of Pt/C catalysts under simulated automotive conditions. By using the “tool box” synthesis method the Pt loading has been changed from low to high Pt loadings, therefore permitting to study the role of Pt on the degradation of high surface area (H...

  4. Catalysts by Design: The Power of Theory

    Energy Technology Data Exchange (ETDEWEB)

    Hammes-Schiffer, Sharon

    2017-03-21

    Theoretical design of effective catalysts, in conjunction with the identification of guiding design principles and strategies, is a Holy Grail in Chemistry. Although further progress will benefit from additional computational advances, theoretical studies have already enhanced the design of molecular electrocatalysts, photocatalysts, and enzymes.

  5. On the degradation of fuel cell catalyst. From model systems to high surface area catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Arenz, M. [Copenhagen Univ. (Denmark). Dept. of Chemistry

    2010-07-01

    In the presented work, as an alternative accelerated degradation tests in the form of half-cell measurements combined with identical location transmission electron microscopy (IL-TEM){sup 10,} {sup 11} are presented. It is demonstrated that for different catalysts the degradation mechanism can be scrutinized in detail. Thus this approach enables the systematic investigation of fuel cell catalyst degradation in a reduced period of time. (orig.)

  6. Optimal catalyst curves: Connecting density functional theory calculations with industrial reactor design and catalyst selection

    DEFF Research Database (Denmark)

    Jacobsen, C.J.H.; Dahl, Søren; Boisen, A.

    2002-01-01

    For ammonia synthesis catalysts a volcano-type relationship has been found experimentally. We demonstrate that by combining density functional theory calculations with a microkinetic model the position of the maximum of the volcano curve is sensitive to the reaction conditions. The catalytic ammo......-principle quantum mechanical calculations of gas-surface interactions, reactor design, and catalyst selection has been established for the first time....

  7. Commercializable power source using heterogeneous hydrino catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Mills, R.L.; Akhtar, K.; Zhao, G.; Chang, Z.; He, J.; Hu, X.; Chu, G. [BlackLight Power, Inc., 493 Old Trenton Road, Cranbury, NJ 08512 (United States)

    2010-01-15

    Using Maxwell's equations, the structure of the electron was derived by Mills as a boundary-value problem wherein the electron comprises the source current of time-varying electromagnetic fields during transitions with the constraint that the bound n = 1 state electron cannot radiate energy. A reaction predicted by the solution involves a resonant, nonradiative energy transfer from otherwise stable atomic hydrogen to a catalyst capable of accepting the energy. Specifically, a catalyst comprises a chemical or physical process with an enthalpy change equal to an integer multiple m of the potential energy of atomic hydrogen, 27.2 eV. The product is H (1/p), fractional Rydberg states of atomic hydrogen called ''hydrino atoms'' wherein n=1/2,1/3,1/4,..,1/p (p {<=} 137 is an integer) replaces the well-known parameter n = integer in the Rydberg equation for hydrogen excited states. The reaction step of a nonradiative energy transfer of an integer multiple of 27.2 eV from atomic hydrogen to the catalyst results in an ionized catalyst and free electrons that may cause the reaction to rapidly cease due to charge accumulation. Li, K, and NaH served as the catalysts to form hydrinos at a rapid rate when a high-surface-area conductive support doped with an oxidant was added to speed up the rate limiting step, the removal of electrons from the catalyst as it is ionized by accepting the nonradiative resonant energy transfer from atomic hydrogen to form hydrinos. The concerted electron-acceptor reaction from the catalyst to oxidant via the support was also exothermic to heat the reactants and enhance the rates. Using water-flow, batch calorimetry, the measured power and energy gain from these heterogeneous catalyst systems were up to over 10 W/cm{sup 3} (reactant volume) and a factor of over six times the maximum theoretical, respectively. The reaction scaled linearly to 580 kJ that developed a power of about 30 kW. Solution {sup 1}H NMR on samples

  8. Carbon-supported Pd-Ir catalyst as anodic catalyst in direct formic acid fuel cell

    Science.gov (United States)

    Wang, Xin; Tang, Yawen; Gao, Ying; Lu, Tianhong

    It was reported for the first time that the electrocatalytic activity of the Carbon-supported Pd-Ir (Pd-Ir/C) catalyst with the suitable atomic ratio of Pd and Ir for the oxidation of formic acid in the direct formic acid fuel cell (DFAFC) is better than that of the Carbon-supported Pd (Pd/C) catalyst, although Ir has no electrocatalytic activity for the oxidation of formic acid. The potential of the anodic peak of formic acid at the Pd-Ir/C catalyst electrode with the atomic ratio of Pd and Ir = 5:1 is 50 mV more negative than that and the peak current density is 13% higher than that at the Pd/C catalyst electrode. This is attributed to that Ir can promote the oxidation of formic acid at Pd through the direct pathway because Ir can decrease the adsorption strength of CO on Pd. However, when the content of Ir in the Pd-Ir/C catalyst is too high the electrocatalytic activity of the Pd-Ir/C catalyst would be decreased because Ir has no electrocatalytic activity for the oxidation of formic acid.

  9. Crystal structure of a DNA catalyst.

    Science.gov (United States)

    Ponce-Salvatierra, Almudena; Wawrzyniak-Turek, Katarzyna; Steuerwald, Ulrich; Höbartner, Claudia; Pena, Vladimir

    2016-01-14

    Catalysis in biology is restricted to RNA (ribozymes) and protein enzymes, but synthetic biomolecular catalysts can also be made of DNA (deoxyribozymes) or synthetic genetic polymers. In vitro selection from synthetic random DNA libraries identified DNA catalysts for various chemical reactions beyond RNA backbone cleavage. DNA-catalysed reactions include RNA and DNA ligation in various topologies, hydrolytic cleavage and photorepair of DNA, as well as reactions of peptides and small molecules. In spite of comprehensive biochemical studies of DNA catalysts for two decades, fundamental mechanistic understanding of their function is lacking in the absence of three-dimensional models at atomic resolution. Early attempts to solve the crystal structure of an RNA-cleaving deoxyribozyme resulted in a catalytically irrelevant nucleic acid fold. Here we report the crystal structure of the RNA-ligating deoxyribozyme 9DB1 (ref. 14) at 2.8 Å resolution. The structure captures the ligation reaction in the post-catalytic state, revealing a compact folding unit stabilized by numerous tertiary interactions, and an unanticipated organization of the catalytic centre. Structure-guided mutagenesis provided insights into the basis for regioselectivity of the ligation reaction and allowed remarkable manipulation of substrate recognition and reaction rate. Moreover, the structure highlights how the specific properties of deoxyribose are reflected in the backbone conformation of the DNA catalyst, in support of its intricate three-dimensional organization. The structural principles underlying the catalytic ability of DNA elucidate differences and similarities in DNA versus RNA catalysts, which is relevant for comprehending the privileged position of folded RNA in the prebiotic world and in current organisms.

  10. Catalysts for Efficient Production of Carbon Nanotubes

    Science.gov (United States)

    Sun, Ted X.; Dong, Yi

    2009-01-01

    Several metal alloys have shown promise as improved catalysts for catalytic thermal decomposition of hydrocarbon gases to produce carbon nanotubes (CNTs). Heretofore almost every experiment on the production of carbon nanotubes by this method has involved the use of iron, nickel, or cobalt as the catalyst. However, the catalytic-conversion efficiencies of these metals have been observed to be limited. The identification of better catalysts is part of a continuing program to develop means of mass production of high-quality carbon nanotubes at costs lower than those achieved thus far (as much as $100/g for purified multi-wall CNTs or $1,000/g for single-wall CNTs in year 2002). The main effort thus far in this program has been the design and implementation of a process tailored specifically for high-throughput screening of alloys for catalyzing the growth of CNTs. The process includes an integral combination of (1) formulation of libraries of catalysts, (2) synthesis of CNTs from decomposition of ethylene on powders of the alloys in a pyrolytic chemical-vapor-decomposition reactor, and (3) scanning- electron-microscope screening of the CNTs thus synthesized to evaluate the catalytic efficiencies of the alloys. Information gained in this process is put into a database and analyzed to identify promising alloy compositions, which are to be subjected to further evaluation in a subsequent round of testing. Some of these alloys have been found to catalyze the formation of carbon nano tubes from ethylene at temperatures as low as 350 to 400 C. In contrast, the temperatures typically required for prior catalysts range from 550 to 750 C.

  11. Process of activation of a palladium catalyst system

    Science.gov (United States)

    Sobolevskiy, Anatoly; Rossin, Joseph A.; Knapke, Michael J.

    2011-08-02

    Improved processes for activating a catalyst system used for the reduction of nitrogen oxides are provided. In one embodiment, the catalyst system is activated by passing an activation gas stream having an amount of each of oxygen, water vapor, nitrogen oxides, and hydrogen over the catalyst system and increasing a temperature of the catalyst system to a temperature of at least 180.degree. C. at a heating rate of from 1-20.degree./min. Use of activation processes described herein leads to a catalyst system with superior NOx reduction capabilities.

  12. Ionic-liquid-supported (ILS) catalysts for asymmetric organic synthesis.

    Science.gov (United States)

    Ni, Bukuo; Headley, Allan D

    2010-04-19

    The asymmetric synthesis of compounds that contain new C-C and C-O bonds remains one of the most important types of synthesis in organic chemistry. Over the years, many different types of catalysts have been designed and used effectively to carry out such transformations. Ionic-liquid-supported (ILS) catalysts represent a new and very effective class of catalysts that are used to facilitate the asymmetric synthesis of such compounds. There are many advantages to using ILS catalysts; they are nontoxic, environmentally benign, and, most important, recyclable. An overview of the design, synthesis, mode of action, and effectiveness of this class of catalysts is reported.

  13. In situ Transmission Electron Microscopy of catalyst sintering

    DEFF Research Database (Denmark)

    DeLaRiva, Andrew T.; Hansen, Thomas Willum; Challa, Sivakumar R.

    2013-01-01

    Recent advancements in the field of electron microscopy, such as aberration correctors, have now been integrated into Environmental Transmission Electron Microscopes (TEMs), making it possible to study the behavior of supported metal catalysts under operating conditions at atomic resolution. Here......, we focus on in situ electron microscopy studies of catalysts that shed light on the mechanistic aspects of catalyst sintering. Catalyst sintering is an important mechanism for activity loss, especially for catalysts that operate at elevated temperatures. Literature from the past decade is reviewed...

  14. An improved method of preparation of nanoparticular metal oxide catalysts

    DEFF Research Database (Denmark)

    2014-01-01

    The present invention concerns an improved method of preparation of nanoparticular vanadium oxide/anatase titania catalysts having a narrow particle size distribution. In particular, the invention concerns preparation of nanoparticular vanadium oxide/anatase titania catalyst precursors comprising...... combustible crystallization seeds upon which the catalyst metal oxide is coprecipitated with the carrier metal oxide, which crystallization seeds are removed by combustion in a final calcining step.......The present invention concerns an improved method of preparation of nanoparticular vanadium oxide/anatase titania catalysts having a narrow particle size distribution. In particular, the invention concerns preparation of nanoparticular vanadium oxide/anatase titania catalyst precursors comprising...

  15. Steam Reforming of Glycerol for Hydrogen Production over Catalyst

    OpenAIRE

    Sadanandam, G.; Sreelatha, N.; Phanikrishna Sharma, M. V.; Kishta Reddy, S.; B. Srinivas; K. Venkateswarlu; T. Krishnudu; Subrahmanyam, M; Durga Kumari, V.

    2012-01-01

    The performance of Ni/SiO2 catalyst for glycerol reforming has been investigated in fixed-bed reactor using careful tailoring of the operational conditions. In this paper, a commercial Engelhard catalyst has been sized and compared to gas product distribution versus catalyst size, water-to-carbon ratio, and stability of the catalyst system. Ni/SiO2 catalysts of three sizes (2×2, 2×4, and 3×5 mm) are evaluated using glycerol: water mixture at 600°C to produce 2 L H2 g−1 cat h−1. The results in...

  16. Reduced ternary molybdenum and tungsten sulfides and hydroprocessing catalysis therewith

    Science.gov (United States)

    Hilsenbeck, Shane J.; McCarley, Robert E.; Schrader, Glenn L.; Xie, Xiaobing

    1999-02-16

    New amorphous molybdenum/tungsten sulfides with the general formula M.sup.n+.sub.2x/n (L.sub.6 S.sub.8)S.sub.x, where L is molybdenum or tungsten and M is a ternary metal, has been developed. Characterization of these amorphous materials by chemical and spectroscopic methods (IR, Raman, PES) shows that the (M.sub.6 S.sub.8).sup.0 cluster units are present. Vacuum thermolysis of the amorphous Na.sub.2x (Mo.sub.6 S.sub.8)S.sub.x .multidot.yMeOH first produces poorly crystalline NaMo.sub.6 S.sub.8 by disproportionation at 800.degree. C. and well-crystallized NaMo.sub.6 S.sub.8 at .gtoreq. 900.degree. C. Ion-exchange of the sodium material in methanol with soluble M.sup.2+ and M.sup.3+ salts (M=Sn, Co, Ni, Pb, La, Ho) produces the M.sup.n+.sub.2x/n (Mo.sub.6 S.sub.8)S.sub.x .multidot.yMeOH compounds. Additionally, the new reduced ternary molybdenum sulfides with the general formula M.sup.n+.sub.2x/n Mo.sub.6 S.sub.8+x (MeOH).sub.y ›MMOS! (M=Sn, Co, Ni) is an effective hydrodesulfurization (HDS) catalyst both as-prepared and after a variety of pretreatment conditions. Under specified pretreatment conditions with flowing hydrogen gas, the SnMoS type catalyst can be stabilized, and while still amorphous, can be considered as "Chevrel phase-like" in that both contain Mo.sub.6 S.sub.8 cluster units. Furthermore, the small cation NiMoS and CoMoS type pretreated catalyst showed to be very active HDS catalysts with rates that exceeded the model unpromoted and cobalt-promoted MoS.sub.2 catalysts.

  17. Alkali resistivity of Cu based selective catalytic reduction catalysts

    DEFF Research Database (Denmark)

    Putluru, Siva Sankar Reddy; Jensen, Anker Degn; Riisager, Anders;

    2012-01-01

    The deactivation of V2O5–WO3–TiO2, Cu–HZSM5 and Cu–HMOR plate type monolithic catalysts was investigated when exposed to KCl aerosols in a bench-scale reactor. Fresh and exposed catalysts were characterized by selective catalytic reduction (SCR) activity measurements, scanning electron microscope...... catalysts revealed that the potassium salt not only deposited on the catalyst surface, but also penetrated into the catalyst wall. Thus, the K/M ratio (M = V or Cu) was high on V2O5–WO3–TiO2 catalyst and comparatively less on Cu–HZSM5 and Cu–HMOR catalysts. NH3-TPD revealed that the KCl exposed Cu–HZSM5...

  18. New catalysts improves heavy feedstock hydro-cracking

    Energy Technology Data Exchange (ETDEWEB)

    Hoek, A.; Huizinga, T.; Esener, A.A.; Maxwell, I.E.; Stork, W. (Koninklijke/Shell Laboratorium, Amsterdam (NL)); van de Meerakker, F.J. (Shell Internationale Petroleum Maatschappij BV, The Hauge (NL)); Sy, O. (Shell Canada Ltd., Oakville, Ontario (CA))

    1991-04-22

    A new zeolite-Y-based second-stage hydrocracking catalyst, designated S-703, has been developed by Shell. Laboratory testing and commercial use show it has significantly improved performance with respect to gas make and middle-distillate selectivity in processing heavy feedstocks when compared to a Shell catalyst, S-753, developed earlier. Further, the new catalyst exhibits enhanced stability. Extensive laboratory testing of the S-703 catalyst has been carried out under single-stage, stacked- bed, two-stage-flow, and series-flow conditions. Commercial experience with the new catalyst has now been obtained in several units. To date, the commercial results have confirmed the laboratory results in terms of the superior, heavy- feedstock processing performance of the new catalyst in all respects. Because the trend toward heavier feedstocks is expected to continue, it is likely that catalysts such as S- 703 will find increasing applications in hydrocrackers in the future.

  19. Near Critical Catalyst Reactant Branching Processes with Controlled Immigration

    CERN Document Server

    Budhiraja, Amarjit

    2012-01-01

    Near critical catalyst-reactant branching processes with controlled immigration are studied. The reactant population evolves according to a branching process whose branching rate is proportional to the total mass of the catalyst. The bulk catalyst evolution is that of a classical continuous time branching process; in addition there is a specific form of immigration. Immigration takes place exactly when the catalyst population falls below a certain threshold, in which case the population is instantaneously replenished to the threshold. Such models are motivated by problems in chemical kinetics where one wants to keep the level of a catalyst above a certain threshold in order to maintain a desired level of reaction activity. A diffusion limit theorem for the scaled processes is presented, in which the catalyst limit is described through a reflected diffusion, while the reactant limit is a diffusion with coefficients that are functions of both the reactant and the catalyst. Stochastic averaging principles under ...

  20. Phosphine-Free EWG-Activated Ruthenium Olefin Metathesis Catalysts

    Science.gov (United States)

    Grela, Karol; Szadkowska, Anna; Michrowska, Anna; Bieniek, Michal; Sashuk, Volodymyr

    Hoveyda-Grubbs catalyst has been successfully fine-tuned by us in order to increase its activity and applicability by the introduction of electron-withdrawing groups (EWGs) to diminish donor properties of the oxygen atom. As a result, the stable and easily accessible nitro-substituted Hoveyda-Grubbs catalyst has found a number of successful applications in various research and industrial laboratories. Some other EWG-activated Hoveyda-type catalysts are commercially available. The results described herewith demonstrate that the activity of ruthenium (Ru) metathesis catalysts can be enhanced by introduction of EWGs without detriment to catalysts stability. Equally noteworthy is the observation that different Ru catalysts turned out to be optimal for different applications. This shows that no single catalyst outperforms all others in all possible applications.

  1. FY 1997 report on the development of excellent catalysts for creation of new industries. New frontier catalyst 21; 1997 nendo chosa hokokusho (shinsangyo sosei no tame no excellence catalyst no kaihatsu). New frontier catalyst 21

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-03-01

    Survey was made for establishment of an effective fast search technique of practical catalysts. Catalyst technology is an important basic technology for industrial fields such as energy and environment fields. In many cases, catalysts have been developed by trial and error consuming a long time and huge research cost. Study was made on efficient analysis and measurement techniques, and systematic production technique of advanced catalysts based on these techniques. This survey was effective in finding a guidance for improving catalysts used in the previous processes, and facilitating searches for fields previously slow in development of catalysts. Advanced catalysts possible to actively selectively produce target products under high pressure/temperature conditions are much in demand. Recently in-situ analysis technology for observing molecules and material surfaces under ultrahigh-pressure/temperature conditions has been studied. Observational study was made on catalytic behavior under catalytic reaction condition using partial oxidation, selective hydrogenation and isomerization as model reactions. 111 refs., 103 figs., 9 tabs.

  2. Kinetic modelling of hydro-treatment reactions by study of different chemical groups; Modelisation cinetique des reactions d`hydrotraitement par regroupement en familles chimiques

    Energy Technology Data Exchange (ETDEWEB)

    Bonnardot, J.

    1998-11-19

    Hydro-treatment of petroleum shortcuts permits elimination of unwanted components in order to increase combustion in engine and to decrease atmospheric pollution. Hydro-desulfurization (HDS), Hydro-denitrogenation (HDN) and Hydrogenation of aromatics (HDA) of a LCO (Light Cycle Oil)-Type gas oil have been studied using a new pilot at a fixed temperature with a NiMo/Al{sub 2}O{sub 3} catalyst. A hydrodynamic study showed that reactions occurring in the up-flow fixed bed reactor that has been used during the experiments, were governed exclusively by chemical reaction rates and not by diffusion. Through detailed chemical analysis, height chemical groups have been considered: three aromatics groups, one sulfided group, one nitrogenized and NH{sub 3}, H{sub 2}S, H{sub 2}. Two Langmuir-Hinshelwood-type kinetic models with either one or two types of sites have been established. The model with two types of site - one site of hydrogenation and one site of hydrogenolysis - showed a better fit in the modeling of the experimental results. This model enables to forecast the influence of partial pressure of H{sub 2}S and partial pressure of H{sub 2} on hydro-treatment reactions of a LCO-type gas oil. (author) 119 refs.

  3. Controlling Proton Delivery through Catalyst Structural Dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Cardenas, Allan Jay P. [Center for Molecular Electrocatalysis, Pacific Northwest National Laboratory, P.O. Box 999, K2-57 Richland WA 99352 USA; 221 Science Center, State University of New York at Fredonia, Fredonia NY 14063 USA; Ginovska, Bojana [Center for Molecular Electrocatalysis, Pacific Northwest National Laboratory, P.O. Box 999, K2-57 Richland WA 99352 USA; Kumar, Neeraj [Center for Molecular Electrocatalysis, Pacific Northwest National Laboratory, P.O. Box 999, K2-57 Richland WA 99352 USA; Hou, Jianbo [Center for Molecular Electrocatalysis, Pacific Northwest National Laboratory, P.O. Box 999, K2-57 Richland WA 99352 USA; Raugei, Simone [Center for Molecular Electrocatalysis, Pacific Northwest National Laboratory, P.O. Box 999, K2-57 Richland WA 99352 USA; Helm, Monte L. [Center for Molecular Electrocatalysis, Pacific Northwest National Laboratory, P.O. Box 999, K2-57 Richland WA 99352 USA; Appel, Aaron M. [Center for Molecular Electrocatalysis, Pacific Northwest National Laboratory, P.O. Box 999, K2-57 Richland WA 99352 USA; Bullock, R. Morris [Center for Molecular Electrocatalysis, Pacific Northwest National Laboratory, P.O. Box 999, K2-57 Richland WA 99352 USA; O' Hagan, Molly [Center for Molecular Electrocatalysis, Pacific Northwest National Laboratory, P.O. Box 999, K2-57 Richland WA 99352 USA

    2016-09-27

    The fastest synthetic molecular catalysts for production and oxidation of H2 emulate components of the active site of natural hydrogenases. The role of controlled structural dynamics is recognized as a critical component in the catalytic performance of many enzymes, including hydrogenases, but is largely neglected in the design of synthetic molecular cata-lysts. In this work, the impact of controlling structural dynamics on the rate of production of H2 was studied for a series of [Ni(PPh2NC6H4-R2)2]2+ catalysts including R = n-hexyl, n-decyl, n-tetradecyl, n-octadecyl, phenyl, or cyclohexyl. A strong correlation was observed between the ligand structural dynamics and the rates of electrocatalytic hydrogen production in acetonitrile, acetonitrile-water, and protic ionic liquid-water mixtures. Specifically, the turnover frequencies correlate inversely with the rates of ring inversion of the amine-containing ligand, as this dynamic process dictates the positioning of the proton relay in the second coordination sphere and therefore governs protonation at either catalytically productive or non-productive sites. This study demonstrates that the dynamic processes involved in proton delivery can be controlled through modifications of the outer coordination sphere of the catalyst, similar to the role of the protein architecture in many enzymes. The present work provides new mechanistic insight into the large rate enhancements observed in aqueous protic ionic liquid media for the [Ni(PPh2NR2)]2+ family of catalysts. The incorporation of controlled structural dynamics as a design parameter to modulate proton delivery in molecular catalysts has enabled H2 production rates that are up to three orders of magnitude faster than the [Ni(PPh2NPh2)]2+complex. The observed turnover frequencies are up to 106 s-1 in acetonitrile-water, and over 107 s-1 in protic ionic liquid-water mixtures, with a minimal increase in overpotential. This material is based upon work supported as part of

  4. Novel Attrition-Resistant Fischer Tropsch Catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Weast, Logan, E.; Staats, William, R.

    2009-05-01

    There is a strong national interest in the Fischer-Tropsch synthesis process because it offers the possibility of making liquid hydrocarbon fuels from reformed natural gas or coal and biomass gasification products. This project explored a new approach that had been developed to produce active, attrition-resistant Fischer-Tropsch catalysts that are based on glass-ceramic materials and technology. This novel approach represented a promising solution to the problem of reducing or eliminating catalyst attrition and maximizing catalytic activity, thus reducing costs. The technical objective of the Phase I work was to demonstrate that glass-ceramic based catalytic materials for Fischer-Tropsch synthesis have resistance to catalytic deactivation and reduction of particle size superior to traditional supported Fischer-Tropsch catalyst materials. Additionally, these novel glass-ceramic-based materials were expected to exhibit catalytic activity similar to the traditional materials. If successfully developed, the attrition-resistant Fischer-Tropsch catalyst materials would be expected to result in significant technical, economic, and social benefits for both producers and public consumers of Fischer-Tropsch products such as liquid fuels from coal or biomass gasification. This program demonstrated the anticipated high attrition resistance of the glass-ceramic materials. However, the observed catalytic activity of the materials was not sufficient to justify further development at this time. Additional testing documented that a lack of pore volume in the glass-ceramic materials limited the amount of surface area available for catalysis and consequently limited catalytic activity. However, previous work on glass-ceramic catalysts to promote other reactions demonstrated that commercial levels of activity can be achieved, at least for those reactions. Therefore, we recommend that glass-ceramic materials be considered again as potential Fischer-Tropsch catalysts if it can be

  5. Catalyst Kinetics Analytical Method Study of Ruthenium

    Institute of Scientific and Technical Information of China (English)

    Kou ming-ze; Zhan hui-ying; Kou zong-yan

    2004-01-01

    Color reactions are used to determine ruthenium utilizing spectrophotometer, but the process need high temperature, long time pyrogenation and miscellaneous extraction and it contaminates the enviroment. As the sensitive degree and simple apparatus of catalyst kinetics analytical method, it was extensively attentcd. The fundmental principle means to determinn a certain chemistry reaction rate accelerated by homogeneous catalyst and determine substantial content using the function of the numerical value of of its and the catalyst concentration. Color acid double azo-reagents (chloro-phosphor group, arsenic group and carboxylic acid group) are sensitive color reagent determining uranium and thorium of lanthanon, but the report is few that it is used to determine ruthenium. Since 1990s, the author studied that the ruthenium was possessed evident catalysis to the fade reaction of oxidant (KIO4, KBrO3) oxidating color acid double azo-reagent in acitidy medium and provided the catalyst kinetics analytical method to determine trace ruthenium.sensitive degree was increased 1 ~2 amount than color reaction. The reaction as:The original concentration of color acid double azo-reagents is A. The instantaneous absorbency after t reaction time is At. In homogeneous catalyst reaction: log(A0/At) = KCRu3+t. Reaction time t is invarible, so log(A0/At) = K' CRu3+t.Color acid double azo-reagents, such as: chlor-azochlorphosphor(CPA-TC),bromic-azochlorphosphor (CPA-TB), DBS-azochlorphosphor(DBS-CPA), DBC-azochlorphosphor (DBC-CPA), DBOK-azochlorpho sphor (DBOK-CPA), p-iodineazochlorphosphor(CPA-PI),p-acetylazochlorphosphor (CPA-PA), azochlorpho sphorⅢ(CPAⅢ), chlor-azoarsenic (TC-AsA),bromic-azoarsenic (TB-AsA), DBS-azoarsenic(DCS-AsA), DCS-azoarsenic(DCS-AsA),azoarsenicⅢ(AsAⅢ), bromicnityrlazoarsenic (DBN-AsA), P-acetylcarboxy lazo-p,P-acetylcarboxylazo, were utilized in catalyst kinetics system. The author obtains the satisfactory results that color acid double azo-rea gents

  6. Catalyst for reduction of nitrogen oxides

    Science.gov (United States)

    Ott, Kevin C.

    2010-04-06

    A Selective Catalytic Reduction (SCR) catalyst was prepared by slurry coating ZSM-5 zeolite onto a cordierite monolith, then subliming an iron salt onto the zeolite, calcining the monolith, and then dipping the monolith either into an aqueous solution of manganese nitrate and cerium nitrate and then calcining, or by similar treatment with separate solutions of manganese nitrate and cerium nitrate. The supported catalyst containing iron, manganese, and cerium showed 80 percent conversion at 113 degrees Celsius of a feed gas containing nitrogen oxides having 4 parts NO to one part NO.sub.2, about one equivalent ammonia, and excess oxygen; conversion improved to 94 percent at 147 degrees Celsius. N.sub.2O was not detected (detection limit: 0.6 percent N.sub.2O).

  7. Relating FTS Catalyst Properties to Performance

    Science.gov (United States)

    Ma, Wenping; Ramana Rao Pendyala, Venkat; Gao, Pei; Jermwongratanachai, Thani; Jacobs, Gary; Davis, Burton H.

    2016-01-01

    During the reporting period June 23, 2011 to August 31, 2013, CAER researchers carried out research in two areas of fundamental importance to the topic of cobalt-based Fischer-Tropsch Synthesis (FTS): promoters and stability. The first area was research into possible substitute promoters that might be used to replace the expensive promoters (e.g., Pt, Re, and Ru) that are commonly used. To that end, three separate investigations were carried out. Due to the strong support interaction of ?-Al2O3 with cobalt, metal promoters are commonly added to commercial FTS catalysts to facilitate the reduction of cobalt oxides and thereby boost active surface cobalt metal sites. To date, the metal promoters examined have been those up to and including Group 11. Because two Group 11 promoters (i.e., Ag and Au) were identified to exhibit positive impacts on conversion, selectivity, or both, research was undertaken to explore metals in Groups 12 - 14. The three metals selected for this purpose were Cd, In, and Sn. At a higher loading of 25%Co on alumina, 1% addition of Cd, In, or Sn was found to-on average-facilitate reduction by promoting a heterogeneous distribution of cobalt consisting of larger lesser interacting cobalt clusters and smaller strongly interacting cobalt species. The lesser interacting species were identified in TPR profiles, where a sharp low temperature peak occurred for the reduction of larger, weakly interacting, CoO species. In XANES, the Cd, In, and Sn promoters were found to exist as oxides, whereas typical promoters (e.g., Re, Ru, Pt) were previously determined to exist in an metallic state in atomic coordination with cobalt. The larger cobalt clusters significantly decreased the active site density relative to the unpromoted 25%Co/Al2O3 catalyst. Decreasing the cobalt loading to 15%Co eliminated the large non-interacting species. The TPR peak for reduction of strongly interacting CoO in the Cd promoted catalyst occurred at a measurably lower temperature

  8. Catalyst Deactivation: Control Relevance of Model Assumptions

    Directory of Open Access Journals (Sweden)

    Bernt Lie

    2000-10-01

    Full Text Available Two principles for describing catalyst deactivation are discussed, one based on the deactivation mechanism, the other based on the activity and catalyst age distribution. When the model is based upon activity decay, it is common to use a mean activity developed from the steady-state residence time distribution. We compare control-relevant properties of such an approach with those of a model based upon the deactivation mechanism. Using a continuous stirred tank reactor as an example, we show that the mechanistic approach and the population balance approach lead to identical models. However, common additional assumptions used for activity-based models lead to model properties that may deviate considerably from the correct one.

  9. Catalytic Acylation of Ethylidenecyclohexane over Zeolite Catalysts

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Some environmentally friendly catalysts such as HY and H-β zeolites,various cation-exchanged β zeolites,and some other solids have been used in the acylation reaction of ethylidenecyclohexane with acetic anhydride at room temperature to synthesize 3-(1-cyclohexenyl)-2-butanone instead of conventional catalysts.The effect of the amount of HY zeolite used on the acylation reaction was investigated.The yield of the acylated product was 72% in the case of n(ethylidenecyclohexane)∶n(acetic anhydride)∶m(HY zeolite)=1 mmol∶10 mmol∶0.100 g,reaction temperature:25 ℃,and reaction time:2 h.The regenerated HY zeolite showed almost the same catalytic activity as the fresh zeolite.

  10. Carbon Xerogel Catalyst for NO Oxidation

    Directory of Open Access Journals (Sweden)

    Manuel F. R. Pereira

    2012-10-01

    Full Text Available Carbon xerogels were prepared by the polycondensation of resorcinol and formaldehyde using three different solution pH values and the gels were carbonized at three different temperatures. Results show that it is possible to tailor the pore texture of carbon xerogels by adjusting the pH of the initial solution and the carbonization temperature. Materials with different textural properties were obtained and used as catalysts for NO oxidation at room temperature. The NO conversions obtained with carbon xerogels were quite high, showing that carbon xerogels are efficient catalysts for NO oxidation. A maximum of 98% conversion for NO was obtained at initial concentration of NO of 1000 ppm and 10% of O2. The highest NO conversions were obtained with the samples presenting the highest surface areas. The temperature of reaction has a strong influence on NO oxidation: the conversion of NO decreases with the increase of reaction temperature.

  11. Manipulating the reactivity of nanoscale catalysts

    DEFF Research Database (Denmark)

    Conradsen, Christian Nagstrup

    . A volcano shaped curve of the activity is found as a function of the copper overlayer thickness. The volcano has an optimum at a copper overlayer thickness of 2 Å corresponding to a coverage of 0.78 ML. The Cu/Ru system is deployed to a real catalyst on a high surface area support. The catalyst also proved...... to the single crystal by sputtering. The defects improve the activity of the single crystal by a factor of 8 for the methanation reaction. CO desorption is studied on both a ruthenium single crystal and on ruthenium nanoparticles. In an collaborative project relating CO desorption, a crossover in CO desorption....... Equally, the desorption profile of a flat ruthenium single crystal can be obtained by annealing a thinfilm of nanoparticles to 900 K for 10 min. In the second project it is found that forming a pseudomorphic overlayer of copper on ruthenium enhances the activity compared to both copper and ruthenium...

  12. Synthesis of Anchored Bimetallic Catalysts via Epitaxy

    Directory of Open Access Journals (Sweden)

    Jiaxin Liu

    2016-06-01

    Full Text Available The development of thermodynamically stable supported bimetallic catalysts for high-temperature reaction is significant and highly desirable but remains a grand challenge. In this work, we report a novel approach that relies on the interaction of metal nanoparticles with the support material to form unique bimetallic nanoparticles, which epitaxially anchor onto the support surface. Such unique nanostructured systems are catalytically active and ultrastable during selected catalytic reactions. In this paper, we describe the synthesis processes of ultrastable PtZn nanoparticles epitaxially anchored onto ZnO nanowires, which primarily consist of {10−10} nanoscale facets. Such anchored PtZn nanoparticles demonstrated good stability during high temperature treatments and selected catalytic reactions. The synthesis approach reported in this work provides a new strategy to develop thermodynamically stable supported bimetallic catalysts.

  13. Asymmetric pair distribution functions in catalysts

    DEFF Research Database (Denmark)

    Clausen, B. S.; Nørskov, Jens Kehlet

    2000-01-01

    The structural parameters, i.e., coordination numbers, bond distances and disorder obtained from the analysis of EXAFS spectra may sometimes be significantly influenced by errors introduced due to the inadequacy of the analysis method applied. Especially in the case of heterogeneous catalysts...... it has been realized that often there is a need to use an improved EXAFS data analysis compared to the simple harmonic approach which works well for well-defined bulk structures. This is due to the fact that catalysts contain highly dispersed or disordered structures with pair distribution functions......, will be described. The method is based on an analysis of the pair distribution functions derived from molecular dynamics simulations of small metal particles and its reliability is demonstrated by comparing structural parameters obtained from independent X-ray diffraction experiments....

  14. Carbon Fiber Composite Monoliths as Catalyst Supports

    Energy Technology Data Exchange (ETDEWEB)

    Contescu, Cristian I [ORNL; Gallego, Nidia C [ORNL; Pickel, Joseph M [ORNL; Blom, Douglas Allen [ORNL; Burchell, Timothy D [ORNL

    2006-01-01

    Carbon fiber composite monoliths are rigid bodies that can be activated to a large surface area, have tunable porosity, and proven performance in gas separation and storage. They are ideal as catalyst supports in applications where a rigid support, with open structure and easy fluid access is desired. We developed a procedure for depositing a dispersed nanoparticulate phase of molybdenum carbide (Mo2C) on carbon composite monoliths in the concentration range of 3 to 15 wt% Mo. The composition and morphology of this phase was characterized using X-ray diffraction and electron microscopy, and a mechanism was suggested for its formation. Molybdenum carbide is known for its catalytic properties that resemble those of platinum group metals, but at a lower cost. The materials obtained are expected to demonstrate catalytic activity in a series of hydrocarbon reactions involving hydrogen transfer. This project demonstrates the potential of carbon fiber composite monoliths as catalyst supports.

  15. Carbon Fiber Composite Monoliths for Catalyst Supports

    Energy Technology Data Exchange (ETDEWEB)

    Contescu, Cristian I [ORNL; Gallego, Nidia C [ORNL; Pickel, Joseph M [ORNL; Blom, Douglas Allen [ORNL; Burchell, Timothy D [ORNL

    2006-01-01

    Carbon fiber composite monoliths are rigid bodies that can be activated to a large surface area, have tunable porosity, and proven performance in gas separation and storage. They are ideal as catalyst supports in applications where a rigid support, with open structure and easy fluid access is desired. We developed a procedure for depositing a dispersed nanoparticulate phase of molybdenum carbide (Mo2C) on carbon composite monoliths in the concentration range of 3 to 15 wt% Mo. The composition and morphology of this phase was characterized using X-ray diffraction and electron microscopy, and a mechanism was suggested for its formation. Molybdenum carbide is known for its catalytic properties that resemble those of platinum group metals, but at a lower cost. The materials obtained are expected to demonstrate catalytic activity in a series of hydrocarbon reactions involving hydrogen transfer. This project demonstrates the potential of carbon fiber composite monoliths as catalyst supports.

  16. Pursuing DNA catalysts for protein modification.

    Science.gov (United States)

    Silverman, Scott K

    2015-05-19

    Catalysis is a fundamental chemical concept, and many kinds of catalysts have considerable practical value. Developing entirely new catalysts is an exciting challenge. Rational design and screening have provided many new small-molecule catalysts, and directed evolution has been used to optimize or redefine the function of many protein enzymes. However, these approaches have inherent limitations that prompt the pursuit of different kinds of catalysts using other experimental methods. Nature evolved RNA enzymes, or ribozymes, for key catalytic roles that in modern biology are limited to phosphodiester cleavage/ligation and amide bond formation. Artificial DNA enzymes, or deoxyribozymes, have great promise for a broad range of catalytic activities. They can be identified from unbiased (random) sequence populations as long as the appropriate in vitro selection strategies can be implemented for their identification. Notably, in vitro selection is different in key conceptual and practical ways from rational design, screening, and directed evolution. This Account describes the development by in vitro selection of DNA catalysts for many different kinds of covalent modification reactions of peptide and protein substrates, inspired in part by our earlier work with DNA-catalyzed RNA ligation reactions. In one set of studies, we have sought DNA-catalyzed peptide backbone cleavage, with the long-term goal of artificial DNA-based proteases. We originally anticipated that amide hydrolysis should be readily achieved, but in vitro selection instead surprisingly led to deoxyribozymes for DNA phosphodiester hydrolysis; this was unexpected because uncatalyzed amide bond hydrolysis is 10(5)-fold faster. After developing a suitable selection approach that actively avoids DNA hydrolysis, we were able to identify deoxyribozymes for hydrolysis of esters and aromatic amides (anilides). Aliphatic amide cleavage remains an ongoing focus, including via inclusion of chemically modified DNA

  17. Process for Functionalizing Biomass using Molybdenum Catalysts

    DEFF Research Database (Denmark)

    2015-01-01

    The present invention concerns a process for converting biomass into useful organic building blocks for the chemical industry. The process involves the use of molybdenum catalysts of the formula Aa+a(MovXxR1yR2zR3e)a*3-, which may be readily prepared from industrial molybdenum compounds.......The present invention concerns a process for converting biomass into useful organic building blocks for the chemical industry. The process involves the use of molybdenum catalysts of the formula Aa+a(MovXxR1yR2zR3e)a*3-, which may be readily prepared from industrial molybdenum compounds....

  18. Alternative deNOx catalysts and technologies

    DEFF Research Database (Denmark)

    Due-Hansen, Johannes

    in the formation of acid rain and photochemical smog. Some basic concepts and reactions regarding the formation and removal of NOx are presented in chapter 1 and 2. Two approaches are undertaken in the present work to reduce the emission of NOx: by means of catalytic removal, and by NO absorption in ionic liquids...... a catalyst less susceptible to the poisons present in the flue gas, a number of catalysts have been synthesized and tested in the present work, all based on commercially available supports. A highly acidic support consisting of sulfated zirconia was chosen based on preliminary studies. A number of different...... permolecule ionic liquid. However, [BMIM]OTf exhibited promising behavior due to its reversible absorption/desorption properties. This in principle allows recycling of the ionic liquid as well as harvesting the NO. The accumulated NO could hereby be used in e.g. the synthesis of nitric acid allowing...

  19. Characterization of fundamental catalytic properties of MoS2/WS2 nanotubes and nanoclusters for desulfurization catalysis - a surface temperature study

    Energy Technology Data Exchange (ETDEWEB)

    U. Burghaus

    2012-07-05

    The prior project consisted of two main project lines. First, characterization of novel nanomaterials for hydrodesulfurization (HDS) applications. Second, studying more traditional model systems for HDS such as vapor-deposited silica-supported Mo and MoSx clusters. In the first subproject, we studied WS2 and MoS2 fullerene-like nanoparticles as well as WS2 nanotubes. Thiophene (C4H4S) was used as the probe molecule. Interestingly, metallic and sulfur-like adsorption sites could be identified on the silica-supported fullerene-particles system. Similar structures are seen for the traditional system (vapor-deposited clusters). Thus, this may be a kinetics fingerprint feature of modern HDS model systems. In addition, kinetics data allowed characterization of the different adsorption sites for thiophene on and inside WS2 nanotube bundles. The latter is a unique feature of nanotubes that has not been reported before for any inorganic nanotube system; however, examples are known for carbon nanotubes, including prior work of the PI. Although HDS has been studied for decades, utilizing nanotubes as nanosized HDS reactors has never been tried before, as far as we know. This is of interest from a fundamental perspective. Unfortunately, the HDS activity of the nanocatalysts at ultra-high vacuum (UHV) conditions was close to the detection limit of our techniques. Therefore, we propose to run experiments at ambient pressure on related nanopowder samples as part of the renewal application utilizing a now-available GC (gas chromatograph) setup. In addition, Ni and Co doped nanocatalyts are proposed for study. These dopants will boost the catalytic activity. In the second subproject of the prior grant, we studied HDS-related chemistry on more traditional supported cluster catalysts. Mo clusters supported by physical vapor deposition (PVD) on silica have been characterized. Two reaction pathways are evident when adsorbing thiophene on Mo and MoSx clusters: molecular adsorption and

  20. Novel Anode Catalyst for Direct Methanol Fuel Cells

    Directory of Open Access Journals (Sweden)

    S. Basri

    2014-01-01

    Full Text Available PtRu catalyst is a promising anodic catalyst for direct methanol fuel cells (DMFCs but the slow reaction kinetics reduce the performance of DMFCs. Therefore, this study attempts to improve the performance of PtRu catalysts by adding nickel (Ni and iron (Fe. Multiwalled carbon nanotubes (MWCNTs are used to increase the active area of the catalyst and to improve the catalyst performance. Electrochemical analysis techniques, such as energy dispersive X-ray spectrometry (EDX, X-ray diffraction (XRD, field emission scanning electron microscopy (FESEM, and X-ray photoelectron spectroscopy (XPS, are used to characterize the kinetic parameters of the hybrid catalyst. Cyclic voltammetry (CV is used to investigate the effects of adding Fe and Ni to the catalyst on the reaction kinetics. Additionally, chronoamperometry (CA tests were conducted to study the long-term performance of the catalyst for catalyzing the methanol oxidation reaction (MOR. The binding energies of the reactants and products are compared to determine the kinetics and potential surface energy for methanol oxidation. The FESEM analysis results indicate that well-dispersed nanoscale (2–5 nm PtRu particles are formed on the MWCNTs. Finally, PtRuFeNi/MWCNT improves the reaction kinetics of anode catalysts for DMFCs and obtains a mass current of 31 A g−1 catalyst.